KR20210075876A - Pressure-sensitive adhesive sheet for processing wafer - Google Patents

Abstract

(Project) The adhesive sheet for a wafer process which can suppress the stick-slip phenomenon at the time of peeling is provided.
(Solution) By the present application, there is provided a pressure-sensitive adhesive sheet for processing a wafer including a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface. ^{The pressure-sensitive adhesive sheet has a stick-slip degree [10 -3} N/10 mm] of 30 or less measured by a predetermined method using a sample for evaluation prepared by affixing the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet to a silicon wafer as an adherend. to be.

Description

Adhesive sheet for wafer processing {PRESSURE-SENSITIVE ADHESIVE SHEET FOR PROCESSING WAFER}

The present invention relates to an adhesive sheet for wafer processing.

In the manufacturing process of a semiconductor device, the process of grinding, cutting, etc. to a wafer (typically a semiconductor wafer) having a circuit formation surface is generally performed in a state in which an adhesive sheet is affixed to the circuit formation surface side. do. As an adhesive sheet, the thing of the form in which the adhesive layer was formed in at least single side|surface of a base material is normally used. For example, when grinding (back grinding) the back surface of a semiconductor wafer, a back grind tape is used to protect the circuit formation surface (outer surface) of the semiconductor wafer and to hold the semiconductor wafer (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2017-212441 Japanese Laid-Open Patent Publication No. 2014-003199

In recent years, with the miniaturization, thickness reduction, and high integration of a semiconductor device, the request|requirement of the thickness reduction of a wafer is increasing. However, when processing a thin wafer, damage to the wafer is more likely to occur. For example, if the wafer is back-grinded until it becomes thinner, the wafer is easily damaged by the load at the time of peeling the back grind tape, resulting in a decrease in yield and a decrease in productivity due to careful peeling operation. etc. may occur. In particular, as described in Patent Document 2, in a wafer (so-called TAIKO (registered trademark) wafer) in which the inner side of the annular convex portion is back-ground as a concave portion, the annular convex portion is adsorbed to fix the wafer, the concave portion supports the back surface Since it will be in a non-existent state, the damage at the time of peeling back grind tape especially tends to occur.

When peeling an adhesive sheet from a wafer as a to-be-adhered body, the stick-slip phenomenon of an adhesive sheet is mentioned as one of the factors by which a wafer is damaged. The stick-slip phenomenon is a combination of a plurality of peeling modes, such as interfacial peeling from the surface (peelable surface) of the adherend, and cohesive failure inside the adhesive, when the pressure-sensitive adhesive sheet is peeled off from the adherend and periodically occurs, resulting in intermittent peeling is an ongoing phenomenon. When the stick-slip phenomenon occurs, the peel force greatly vibrates with the progress of peeling, so that the load applied to the adherend at the time of peeling becomes larger, which may cause damage to the adherend.

The present invention was created in view of the above circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive sheet for wafer processing capable of reducing the load applied to an adherend by suppressing the stick-slip phenomenon at the time of peeling.

According to this specification, the adhesive sheet for wafer processing containing the adhesive layer which comprises an adhesive surface is provided. Here, the said adhesive sheet uses the evaluation sample produced by sticking the said adhesive surface of the said adhesive sheet to a silicon wafer as a to-be-adhered body, The peeling rate by at least any method of the following method A, method B, and method C ^{The stick-slip degree [10 -3} N/10 mm] measured under the condition of 300 mm/min is 30 or less.

(Method A) An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the sample for evaluation, and then the degree of stick-slip when the pressure-sensitive adhesive sheet is peeled from the adherend is measured.

(Method B) The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and then the stick-slip degree when the pressure-sensitive adhesive sheet is peeled from the adherend is measured.

(Method C) After irradiating an active energy ray to the sample for evaluation from the side opposite to the adherend of the adhesive sheet, and supplying an aqueous peeling solution to the interface between the adhesive sheet and the adherend, the adhesive The stick-slip degree when the sheet is peeled from the adherend is measured.

Since the stick-slip phenomenon at the time of peeling is suppressed in such an adhesive sheet for wafer processing, the load given to the to-be-adhered body at the time of peeling can be reduced, and damage to a to-be-adhered body can be suppressed.

In some preferred embodiments of the technology disclosed herein, the pressure-sensitive adhesive sheet has a peel force of 0.10 N/10 measured by at least any of the following methods E, F, and G using the evaluation sample. mm or less.

(Method E) An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the evaluation sample, and then the peeling force at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.

(Method F) The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and then the peeling force at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.

(Method G) After irradiating the sample for evaluation with an active energy ray from the side opposite to the adherend of the adhesive sheet, and supplying an aqueous peeling solution to the interface between the adhesive sheet and the adherend, the adhesive The peeling force at the time of peeling a sheet|seat from the said to-be-adhered body is measured.

Such a pressure-sensitive adhesive sheet for wafer processing can be peeled off with a light peeling force in the peeling step from the adherend, so that the burden on the adherend at the time of peeling can be reduced.

In one preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive sheet is peeled when the pressure-sensitive adhesive sheet is peeled from the adherend without irradiating the sample for evaluation with an active energy ray using the evaluation sample. The force is 0.20 N/10 mm or more. The said adhesive sheet for a wafer process is a state which is not irradiated with an active energy ray WHEREIN: It is easy to show high adhesive force. For this reason, it is easy to suppress that an adhesive sheet peels from a to-be-adhered body in the process (for example, back grinding process) of processing a to-be-adhered body in the state which stuck the said adhesive sheet to a to-be-adhered body.

In a preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive layer is an active energy ray-curable pressure-sensitive adhesive layer. According to such an adhesive sheet, since peeling force falls easily after irradiating an active energy ray, peeling force changes large before and behind irradiation of an active energy ray. For this reason, in the said adhesive sheet, the adhesive force in a processing process (for example, back grinding process), and light peeling in a peeling process are compatible, and it is easy to achieve. Moreover, according to the said adhesive sheet, since the stick-slip degree after irradiation with an active energy ray falls easily, the burden given to the to-be-adhered body at the time of peeling tends to be suppressed, and it is easy to suppress damage to the to-be-adhered body at the time of peeling. .

In one preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive sheet has a stick-slip degree [10 ^-3 N measured by at least one of method B and method C under conditions of a peeling rate of 300 mm/min. /10 mm] is 10 or less. Since the stick-slip phenomenon at the time of peeling is further suppressed in such an adhesive sheet for a wafer process, the load given to a to-be-adhered body can be reduced more and damage to a to-be-adhered body can be suppressed more.

In one preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive sheet has a stick-slip degree [10 ^-3 N/ 10 mm] is less than 3. Since the stick-slip phenomenon at the time of peeling is especially suppressed in such an adhesive sheet for a wafer process, the load given to a to-be-adhered body can be reduced more and damage to a to-be-adhered body can be suppressed more.

In one preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive sheet has a peeling force of less than 0.050 N/10 mm measured by at least one of the method F and the method G using the evaluation sample. The said adhesive sheet for wafer processing WHEREIN: In a peeling process from a to-be-adhered body, especially remarkable light peeling can be achieved.

In addition, the suitably combining each element mentioned above can also be included in the scope of the invention for which protection by a patent is requested|required by this patent application.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically one structural example of the adhesive sheet for a wafer process.
2 : is sectional drawing which shows typically another structural example of the adhesive sheet for a wafer process.
3 : is sectional drawing which shows typically another structural example of the adhesive sheet for a wafer process.
4 : is sectional drawing which shows typically another one structural example of the adhesive sheet for a wafer process.
5 : is sectional drawing which shows typically another structural example of the adhesive sheet for a wafer process.
6 : is sectional drawing which shows typically another one structural example of the adhesive sheet for a wafer process.
7 : is a graph (x-axis: peeling distance, y-axis: peeling force) which shows typically the peeling force from the to-be-adhered body of the adhesive sheet for a wafer process.

Hereinafter, preferred embodiments of the present invention will be described. In addition, matters necessary for the implementation of the present invention other than those specifically mentioned in this specification can be understood by those skilled in the art based on the teachings for the implementation of the invention described in this specification and the technical common sense at the time of filing. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field. In addition, in the following drawings, the same code|symbol may be attached|subjected to the member and site|part which show the same action, and description may be given, and overlapping description may be abbreviate|omitted or simplified. In addition, embodiment described in the drawing is modeled in order to demonstrate this invention clearly, and does not necessarily show exactly the size and scale of the actually provided product.

In this specification, the polymer main chain refers to a chain structure constituting the skeleton of the polymer. In addition, the side chain of a polymer shall refer to the group (pendant, a side group) couple|bonded with the said main chain, or a molecular chain which can be regarded as a pendant.

In this specification, the term "acrylic polymer" refers to a polymer derived from a monomer raw material containing more than 50% by weight of an acrylic monomer (preferably more than 70% by weight, for example, more than 90% by weight). The said acrylic monomer means the monomer which has at least 1 piece(s) of (meth)acryloyl group in 1 molecule. In addition, in this specification, "(meth)acryloyl" is the meaning which points out acryloyl and methacryloyl comprehensively. Similarly, "(meth)acrylate" refers to acrylate and methacrylate, and "(meth)acryl" refers to acryl and methacryl inclusively, respectively.

In addition, in this specification, "active energy ray" is a concept including light such as ultraviolet rays, visible rays, and infrared rays, and radiation such as α-rays, β-rays, γ-rays, electron beams, neutron rays, and X-rays.

<Characteristics of the adhesive sheet>

The adhesive sheet for a wafer process disclosed herein preferably suppresses the stick-slip phenomenon which arises at the time of peeling from a to-be-adhered body. Here, in this specification, the degree of the stick-slip phenomenon which arises when peeling an adhesive sheet from a to-be-adhered body is called "stick-slip degree." In one preferable aspect of the adhesive sheet disclosed herein, the stick-slip degree is suppressed as low as below a predetermined value. In such a pressure-sensitive adhesive sheet, since the stick-slip phenomenon occurring at the time of peeling from the adherend is preferably suppressed, vibrations due to the peeling force accompanying the progress of the peeling are suppressed, and the burden on the adherend can be reduced. . For this reason, according to the adhesive sheet with a low stick-slip degree, it is easy to suppress the damage to the to-be-adhered body at the time of peeling.

The measuring method of the "stick slip degree" in this specification is demonstrated, referring FIG. 7 is a graph (x-axis is peeling distance, y-axis is peeling force) of a general peeling force curve of an adhesive sheet. The stick-slip degree SS of the pressure-sensitive adhesive sheet is obtained by the following general formula (1) when the peel force curve is expressed as y = f(x), and only the reference length L is extracted from the peel force curve in the direction of the average line. becomes Here, since the peeling behavior of the pressure-sensitive adhesive sheet is not in a stable state in many cases in the initial stage of peeling from the time the pressure-sensitive adhesive sheet starts to be peeled from the adherend until it reaches a predetermined peeling behavior, the stick-slip degree measurement is It is preferable to start from the place where the peeling of the pressure-sensitive adhesive sheet from the adherend was advanced to a predetermined distance. In addition, what is necessary is just to set the reference length L suitably according to the peeling behavior of an adhesive sheet, etc. ^{The stick-slip degree [10 -3} N/10 mm] of the pressure-sensitive adhesive sheet described herein is specifically measured by the method described in Examples described later.

The pressure-sensitive adhesive sheet disclosed herein uses a sample for evaluation produced by affixing the pressure-sensitive adhesive sheet to a silicon wafer as an adherend, and uses at least any one of the following methods A, B, and C with a peeling rate of 300 mm/ ^{The stick-slip degree [10 -3} N/10 mm] measured under the condition of 1 minute is kept low below a predetermined value. According to such an adhesive sheet, since the stick-slip phenomenon is suppressed, the damage to the to-be-adhered body at the time of peeling is suppressed easily.

^{In one preferred aspect of the pressure-sensitive adhesive sheet disclosed herein, the degree of stick slip [10 -3} N/10 mm] measured under the condition of a peeling rate of 300 mm/min by at least one of the following method B and the following method C is , is kept low below a predetermined value. According to such an adhesive sheet, since the stick-slip phenomenon at the time of peeling is suppressed more, there exists a tendency for the damage to the to-be-adhered body at the time of peeling to be suppressed more. ^{From the same viewpoint, the adhesive sheet in which the stick-slip degree [10 -3} N/10 mm] measured by the following method C under the conditions of a peeling rate of 300 mm/min is suppressed low below a predetermined value is preferable.

Method A: An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the sample for evaluation, and thereafter, the stick-slip degree SSw0 is measured when the pressure-sensitive adhesive sheet is peeled from the adherend.

Method B: The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and thereafter, the stick-slip degree SSd1 at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.

Method C: After irradiating the sample for evaluation with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and supplying an aqueous peeling solution to the interface between the pressure-sensitive adhesive sheet and the adherend, the pressure-sensitive adhesive sheet The stick-slip at the time of peeling from the said to-be-adhered body also measures SSw1.

In one preferred aspect of the pressure-sensitive adhesive sheet disclosed herein, the stick-slip degree SSw0 (hereinafter also referred to as “unirradiated water peeling stick-slip degree SSw0”) measured by the method A may be approximately 150 or less. From the viewpoint of suppressing damage to the adherend at the time of peeling, in some aspects, the unirradiated water peeling stick slip SSw0 may be, for example, 100 or less, 50 or less, preferably 30 or less, and more Preferably it is 25 or less, and 22 or less may be sufficient. The lower limit of the unirradiated water peeling stick slip SSw0 is not particularly limited, but from the viewpoint of balancing the adhesive properties, for example, may be 0.5 or more, 1 or more, 5 or more, 10 or more, 15 or more. may be In addition, the unirradiated water peeling stick slip degree SSw0 is, when the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is an active energy ray-curable pressure-sensitive adhesive layer, in the sample for evaluation in which the pressure-sensitive adhesive sheet is not irradiated with active energy rays, the pressure-sensitive adhesive sheet A value measured when water is peeled from an adherend is adopted.

In one preferred aspect of the pressure-sensitive adhesive sheet disclosed herein, the stick-slip degree SSd1 (hereinafter also referred to as "normal peel-off stick-slip degree SSd1 after irradiation") measured by the method B above may be approximately 100 or less. From the viewpoint of suppressing damage to the adherend during peeling, in some embodiments, the normal peeling stick slip after irradiation SSd1 may be, for example, 50 or less, preferably 30 or less, and more preferably 20 or less. and more preferably 15 or less (for example, 10 or less). Normal peeling stick slip after irradiation The lower limit of SSd1 is not particularly limited, but from the viewpoint of balancing the adhesive properties, for example, may be 0.10 or more, 0.50 or more, 1.0 or more, 1.50 or more, or 2.0 or more. may be

In one preferred aspect of the pressure-sensitive adhesive sheet disclosed herein, the stick-slip degree SSw1 (hereinafter also referred to as “water peeling stick-slip degree SSw1 after irradiation”) measured by the method C above may be approximately 100 or less. From the viewpoint of suppressing damage to the adherend during peeling, in some embodiments, the water peeling stick slip degree SSw1 after irradiation may be, for example, 50 or less, preferably 30 or less, more preferably 20 or less , more preferably 10 or less (for example, less than 3), and may be less than 1. The lower limit of the water peeling stick slip SSw1 after irradiation is not particularly limited, but may be, for example, 0.01 or more, 0.10 or more, 0.20 or more, or 0.25 or more from the viewpoint of balancing the adhesive properties.

In addition, using the evaluation sample, the pressure-sensitive adhesive sheet is normally peeled from the adherend without irradiating the pressure-sensitive adhesive sheet with active energy rays (that is, peeled without using a peeling solution such as an aqueous peeling solution). The stick-slip degree SSd0 (hereinafter also referred to as "unirradiated normal peeling stick-slip degree SSd0") is not specifically limited. From the viewpoint of balancing the adhesive properties, the unirradiated normal peeling stick slip degree SSd0 is usually preferably 1.0 or more and 200 or less, 5.0 or more and 150 or less, 10 or more and 100 or less, and 15 or more and 50 or less. , 15 or more and 30 or less may be sufficient, and 15 or more and 25 or less may be sufficient.

In a preferred aspect of the technology disclosed herein, the pressure-sensitive adhesive sheet has a peeling force measured by at least any of the following methods E, F, and G using the evaluation sample, which is lower than a predetermined value or less. is suppressed. According to such an adhesive sheet, since light peeling can be implement|achieved in a peeling process, the damage to a to-be-adhered body at the time of peeling is suppressed easily. The peeling force of an adhesive sheet is specifically measured by the method as described in the Example mentioned later.

In one preferable aspect of the adhesive sheet disclosed herein, the peeling force measured by at least one of the following method F and the following method G is suppressed low below a predetermined value. According to such an adhesive sheet, since lighter peeling can be implement|achieved in a peeling process, damage to a to-be-adhered body at the time of peeling is suppressed easily. From a similar viewpoint, the adhesive sheet by which the peeling force measured by the following method G is suppressed low below a predetermined value is more preferable.

Moreover, in one preferable aspect of the technique disclosed herein, the peeling force of the said adhesive sheet measured by the following method H using the said sample for evaluation is a predetermined value or more. Such an adhesive sheet is easy to exhibit the adhesive force suitable for an adhesive sheet in processing processes, such as a back grinding process.

Method E: An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the sample for evaluation, and then the peeling force Fw0 at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.

Method F: The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and then the peeling force Fd1 at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.

Method G: After irradiating the sample for evaluation with an active energy ray from the side opposite to the adherend of the adhesive sheet, and supplying an aqueous peeling solution to the interface between the adhesive sheet and the adherend, the adhesive sheet was removed The peeling force Fw1 at the time of peeling from the said to-be-adhered body is measured.

Method H: The peeling force Fd0 at the time of peeling the said adhesive sheet from the said to-be-adhered body is measured without irradiating an active energy ray to the said sample for evaluation.

In one preferred aspect of the technology disclosed herein, the peeling force Fw0 (hereinafter also referred to as "unirradiated water peeling force Fw0") measured by the method E above is usually 5.0 N/10 mm or less. , Preferably it is 2.0 N/10 mm or less, More preferably, it is 1.0 N/10 mm or less, More preferably, it is 0.50 N/10 mm or less (for example, 0.10 N/10 mm or less). Although the lower limit in particular of the peeling force Fw0 of unirradiated water is not restrict|limited, From the viewpoint of improving the adhesiveness to a to-be-adhered body, in some aspects, Preferably it is 0.01 N/10 mm or more, For example, 0.02 N/10 mm or more. 0.03 N/10 mm or more may be sufficient, 0.05 N/10 mm or more may be sufficient, 0.075 N/10 mm or more may be sufficient, and 0.08 N/10 mm or more may be sufficient as it. In addition, the said unirradiated water peeling force Fw0 is, when the adhesive layer of an adhesive sheet is an active energy ray-curable adhesive layer, in the sample for evaluation before an active energy ray is irradiated to the said adhesive sheet. The value measured when making water peeling is employ|adopted.

In one preferred aspect of the technology disclosed herein, the peel force Fd1 (hereinafter also referred to as "normal peel force Fd1 after irradiation") measured by the method F above is usually preferably 1.0 N/10 mm or less, and , Preferably it is 0.10 N/10 mm or less, More preferably, it is 0.08 N/10 mm or less, More preferably, it is 0.05 N/10 mm or less (for example, 0.03 N/10 mm or less). The lower limit of the normal peeling force Fd1 after irradiation is not particularly limited, but from the viewpoint of taking a balance with the adhesive performance, in some embodiments, 0.001 N/10 mm or more, 0.002 N/10 mm or more, 0.004 N/10 mm or more 10 mm or more may be sufficient.

In one preferred aspect of the technology disclosed herein, the peeling force Fw1 (hereinafter also referred to as "water peeling force Fw1 after irradiation") measured by the method G above is usually preferably 1.0 N/10 mm or less, and , Preferably it is 0.10 N/10 mm or less, More preferably, it is 0.05 N/10 mm or less, More preferably, it is 0.01 N/10 mm or less (for example, 0.008 N/10 mm or less). Although the lower limit in particular of the water peeling force Fw1 after irradiation is not restrict|limited, From a viewpoint of taking a balance with adhesive performance, in some aspects, it may be 0.0005 N/10 mm or more, it may be 0.001 N/10 mm or more, It may be 0.002 N/ 10 mm or more may be sufficient.

In one preferred aspect of the technology disclosed herein, the peeling force Fd0 (hereinafter also referred to as "unirradiated normal peeling force Fd0") measured by the method H is usually 0.05 N/10 mm or more. , Preferably it is 0.10 N/10 mm or more, More preferably, it is 0.20 N/10 mm or more, More preferably, it is 0.30 N/10 mm or more. From the viewpoint of improving the adhesion with the adherend at the time of wafer (typically a semiconductor wafer) processing, in some aspects, the unirradiated normal peeling force Fd0 is preferably 0.50 N/10 mm or more, more preferably is 1.0 N/10 mm or more, more preferably 1.50 N/10 mm or more (for example, 2.0 N/10 mm or more). Although the upper limit of the unirradiated normal peeling force Fd0 is not specifically limited, From a viewpoint of achieving light peeling at the time of peeling, it is usually appropriate that it is about 15 N/10 mm or less, Preferably it is 10 N/10 mm or less. , More preferably, it is 5.0 N/10 mm or less, 3.0 N/10 mm or less may be sufficient, and 1.0 N/10 mm or less may be sufficient.

As a tensile tester used to measure the normal peeling stick slip degrees SSd0, SSd1 and water peeling stick slip degrees SSw0, SSw1, a precision universal testing machine manufactured by Kyowa Interface Science Co., Ltd. "Model: VPA-3" or an equivalent product may be used. can In a measurement, an appropriate backing material (For example, PET film with a thickness of about 25 micrometers) can be affixed and reinforced on the adhesive sheet of a measurement object as needed.

As a tensile tester used for the measurement of the normal peeling forces Fd0, Fd1 and water peeling forces Fw0, Fw1, a precision universal testing machine manufactured by TOMSI "Model: DT9503-1000N" or an equivalent thereof can be used. In a measurement, an appropriate backing material (For example, PET film with a thickness of about 25 micrometers) can be affixed and reinforced on the adhesive sheet of a measurement object as needed.

As a silicon wafer as an adherend used to prepare the sample for evaluation, the same or equivalent product as in the examples described later can be used. In addition, the adhesive sheet disclosed here is not limited to what is used for the same wafer as the silicon wafer used for producing the said sample for evaluation. That is, the use of the pressure-sensitive adhesive sheet disclosed herein is not limited to processing a silicon wafer as an adherend used for measurement of stick-slip degree and/or peeling force, and can also be used for processing other wafers.

<Structural example of an adhesive sheet>

The adhesive sheet for a wafer process disclosed here is equipped with an adhesive layer. This pressure-sensitive adhesive layer typically constitutes at least one surface of the pressure-sensitive adhesive sheet. The PSA sheet may be an PSA sheet having a PSA layer on one side or both surfaces of a base material (support) attached thereto, or may be a PSA sheet (substrateless PSA sheet) without a base material.

The concept of the adhesive sheet referred to herein may include what is called an adhesive tape, an adhesive label, an adhesive film, or the like. In addition, although the said adhesive layer is typically formed continuously, it is not limited to this form, For example, the adhesive layer formed in regular or random patterns, such as a dotted form and stripe shape, may be sufficient. In addition, roll shape may be sufficient as the adhesive sheet provided by this specification, and sheet shape may be sufficient as it. Alternatively, the pressure-sensitive adhesive sheet may be further processed into various shapes.

The pressure-sensitive adhesive sheet disclosed herein may have, for example, a cross-sectional structure schematically shown in FIGS. 1 to 6 . Among these, FIG. 1 and FIG. 2 are structural examples of the adhesive sheet with a single-sided adhesive base material (single-sided adhesive sheet with a base material). As for the adhesive sheet 1 shown in FIG. 1, the adhesive layer 21 is formed on one surface 10A (non-peelable) of the base material 10, The surface (adhesive surface) 21A of the adhesive layer 21 is , at least the side of the pressure-sensitive adhesive layer is protected by a release liner 31 serving as a release surface. The adhesive sheet 2 shown in FIG. 2 has the structure in which the adhesive layer 21 was formed in 1 surface 10A (non-peelability) of the base material 10. In this pressure-sensitive adhesive sheet 2, the other surface 10B of the base material 10 is a release surface, and when the pressure-sensitive adhesive sheet 2 is wound, the pressure-sensitive adhesive layer 21 is brought into contact with the other surface 10B, The surface (adhesive surface) 21A of the pressure-sensitive adhesive layer is protected by the other surface 10B of the base material 10 .

3 and 4 are structural examples of a double-sided adhesive type pressure-sensitive adhesive sheet with a base material (double-sided pressure-sensitive adhesive sheet with a base material). The adhesive sheet 3 shown in FIG. 3 is an adhesive layer (1st adhesive layer) 21, an adhesive layer on the 1st surface 10A and the 2nd surface 10B (both non-peelable) of the base material 10. (2nd adhesive layer) 22 are formed, respectively, The surface (1st adhesive surface) of the 1st adhesive layer 21 and the surface (2nd adhesive surface) of the 2nd adhesive layer 22 are at least the adhesive It has a structure in which the layer side was protected by the release liners 31 and 32 each serving as a release surface. The adhesive sheet 4 shown in FIG. 4 is on the 1st surface 10A and the 2nd surface 10B (both non-peelable) of the base material 10, respectively, the 1st adhesive layer 21, the 2nd adhesive layer ( 22) is formed, and the surface (first adhesive surface) of the 1st adhesive layer 21 among them has the structure protected by the release liner 31 whose both surfaces become a peeling surface. The pressure-sensitive adhesive sheet 4 is wound by winding the pressure-sensitive adhesive sheet 4 to bring the surface (second pressure-sensitive adhesive surface) of the second pressure-sensitive adhesive layer 22 into contact with the back surface of the release liner 31, whereby the second pressure-sensitive adhesive surface is also peeled off. It can be set as the structure protected by the liner 31.

5 and 6 are structural examples of a base material-less double-sided adhesive adhesive sheet (base-less double-sided adhesive sheet). As for the adhesive sheet 5 shown in FIG. 5, one surface (1st adhesive surface) 21A and the other surface (2nd adhesive surface) 21B of the base material-less adhesive layer 21 are at least the adhesive It has a structure in which the layer side was protected by the release liners 31 and 32 each serving as a release surface. The pressure-sensitive adhesive sheet 6 shown in FIG. 6 has a configuration in which one surface (first adhesive surface) 21A of the pressure-sensitive adhesive layer 21 is protected by a release liner 31 on both surfaces of which is a release surface, , when this is wound, the other surface (second adhesive surface) 21B of the pressure-sensitive adhesive layer 21 abuts against the back surface of the release liner 31, so that the other surface 21B is also protected with the release liner 31 It can be done with the configured configuration.

A base materialless or double-sided adhesive sheet with a base material can be used as a single-sided adhesive sheet with a base material by bonding a non-peelable base material together to one adhesive surface.

The pressure-sensitive adhesive sheet before use (before sticking to an adherend) may be in the form of a pressure-sensitive adhesive sheet with a release liner in which the pressure-sensitive adhesive surface is protected with a release liner, as shown, for example, in FIGS. 1 to 6 . The release liner is not particularly limited, and for example, a release liner in which the surface of a liner substrate such as a resin film or paper is subjected to a release treatment, a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin-based resin (polyethylene, polypropylene) etc.), a release liner made of a low-adhesive material can be used. For the said peeling treatment, for example, a peeling agent, such as a silicone type and a long-chain alkyl type, can be used. In some embodiments, a resin film subjected to a release treatment can be preferably employed as a release liner.

When the pressure-sensitive adhesive sheet disclosed herein is in the form of a double-sided pressure-sensitive adhesive sheet having a substrate attached thereto or a substrate-less double-sided pressure-sensitive adhesive sheet, the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive surface (first pressure-sensitive adhesive) and the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive surface (second pressure-sensitive adhesive sheet) The same composition may be sufficient as an adhesive), and a different composition may be sufficient as it. A substrate-less double-sided pressure-sensitive adhesive sheet having a different composition on the first pressure-sensitive adhesive surface and the second pressure-sensitive adhesive surface can be realized by, for example, a multi-layered pressure-sensitive adhesive layer in which two or more pressure-sensitive adhesive layers having different compositions are directly laminated (without interposing a base material). can

Some aspects of the adhesive sheet disclosed herein WHEREIN: The adhesive sheet has the adhesive surface comprised by the adhesive layer (active energy ray-curable adhesive layer) which has active energy ray sclerosis|hardenability. The adhesive sheet which concerns on some other aspect has the adhesive surface comprised with the adhesive layer (inactive energy ray-curable adhesive layer) which does not have active energy ray sclerosis|hardenability. In the case of a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive surface and a second pressure-sensitive adhesive surface, the first pressure-sensitive adhesive surface and the second pressure-sensitive adhesive surface may be both an active energy ray-curable pressure-sensitive adhesive layer and an inactive energy ray-curable pressure-sensitive adhesive layer. The adhesive surface comprised by may be sufficient, one may be the adhesive surface comprised by the active energy ray-curable adhesive layer, and the adhesive surface comprised by the other inactive energy ray-curable adhesive layer may be sufficient. The pressure-sensitive adhesive sheet disclosed herein is a single-sided pressure-sensitive adhesive sheet with a substrate having at least one pressure-sensitive adhesive surface constituted by an active energy ray-curable pressure-sensitive adhesive layer or an inactive energy ray-curable pressure-sensitive adhesive layer, a double-sided pressure-sensitive adhesive sheet with a substrate, or a substrate-less double-sided It may be preferably implemented in the form of an adhesive sheet. Especially, the single-sided adhesive sheet with a base material which has an adhesive surface comprised by an active energy ray-curable adhesive layer or an inactive energy ray-curable adhesive layer is preferable.

<Adhesive layer>

The pressure-sensitive adhesive layer (for example, the active energy ray-curable pressure-sensitive adhesive layer) constituting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet disclosed herein is an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive (a natural rubber type, a synthetic rubber type, a mixture thereof, etc.), It may be a pressure-sensitive adhesive layer comprising one or two or more types of pressure-sensitive adhesives selected from known various pressure-sensitive adhesives such as polyester pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyether-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, and fluorine-based pressure-sensitive adhesives. Here, an acrylic adhesive means the adhesive which uses an acrylic polymer as a base polymer. It has the same meaning also about a rubber-type adhesive and other adhesive.

In addition, in this specification, the "base polymer" of an adhesive means the main component of the polymer contained in the adhesive. In addition, in this specification, a "main component" refers to a component contained in excess of 50 weight%, unless otherwise specified.

(Acrylic adhesive layer)

In some aspects of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer may be an acrylic pressure-sensitive adhesive layer including an acrylic pressure-sensitive adhesive as a main component. The adhesive sheet provided with an acrylic adhesive layer WHEREIN: The adhesive characteristic suitable for a wafer process, and the light-peelability by water peeling can be compatible preferably. An acrylic adhesive layer is preferable also from a viewpoint of being easy to provide the active energy ray sclerosis|hardenability mentioned later.

As an acrylic adhesive, it is preferable to contain as a base polymer the acrylic polymer which is a polymer of a monomer raw material containing an alkyl (meth)acrylate, or a modified|denatured product by its chemical modification, etc., for example. As a structural component of the said monomer raw material, the alkyl (meth)acrylate which has a C1-C20 linear or branched alkyl group at the ester terminal can be used preferably. Hereinafter, an alkyl (meth)acrylate having an alkyl group having X or more Y or less at the ester terminal is _{sometimes referred to as "C X -Y} alkyl (meth) acrylate." Since adhesive properties suitable for wafer processing applications are easily obtained, the C _1-20 alkyl (meth)acrylate _{is preferably a C 1-14} (eg C _1-12 ) alkyl (meth)acrylate. In addition, as the C _1-20 alkyl acrylate, a C _1-20 (eg, C _1-14 , typically C _1-12 ) alkyl acrylate is preferable.

Non-limiting examples of C _1-20 alkyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, Isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, etc. are mentioned. These alkyl (meth)acrylates can be used individually by 1 type or in combination of 2 or more type. Preferred alkyl (meth)acrylates include ethyl acrylate (EA), n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), and lauryl acrylate (LA). In some embodiments, the monomer raw material preferably includes at least one of EA, BA, 2EHA and LA, more preferably includes at least one of EA, BA, and 2EHA, and at least one of BA and 2EHA It is more preferable to include one.

Since it is easy to balance the characteristics, in some embodiments, _{the proportion of C 1-20} alkyl (meth) acrylate in the monomer raw material is usually 40% by weight or more, and more than 50% by weight. It is preferable, for example, 55 weight% or more may be sufficient, 60 weight% or more may be sufficient, 65 weight% or more may be sufficient, and 70 weight% or more may be sufficient. For the same reason, the _{ratio of C 1-20} alkyl (meth)acrylate in the monomer raw material is usually preferably 99.9 wt% or less, and may be 99 wt% or less, or 98 wt% or less. From the viewpoint of facilitating formation of an adhesive sheet suitable for light peeling by supplying an aqueous peeling solution to a peeling wire from an adherend, in some embodiments, C _1-20 alkyl (meth) in the monomer raw material The ratio of the acrylate may be, for example, 95 weight% or less, 85 weight% or less, less than 80 weight%, and 70 weight% or less may be sufficient as it.

In some preferred embodiments, the alkyl (meth) acrylate is an alkyl (meth) acrylate A1 (ie, C _1-9 alkyl (meth) acrylate) having an alkyl group having 9 or less carbon atoms at the ester terminal. include Alkyl (meth)acrylate A1 can be used individually by 1 type or in combination of 2 or more type. According to the structure in which the length of the side chain alkyl group is limited in this way, there exists a tendency for the high cohesive force which can prevent an adhesive residue to a high degree to be acquired. For example, in a configuration having a carbon-carbon double bond in the side chain (typically at the end of the side chain) of the polymer, the length of the side chain alkyl group is limited, so that the reaction of the carbon-carbon double bond during curing treatment This can go smoothly. Moreover, since the length of a side chain alkyl group is restrict|limited, the adhesive sheet provided with the adhesive layer containing the polymer obtained from the said monomer is a peeling method of supplying aqueous peeling liquid, such as water, to the peeling wire from a to-be-adhered body. It can peel efficiently from the to-be-adhered body.

The proportion of the alkyl (meth)acrylate A1 in the whole monomer raw material is suitably about 30% by weight or more, and preferably about 40% by weight from the viewpoint of better expressing the action of the alkyl (meth)acrylate A1. % or more, more preferably about 55% by weight or more. In some aspects, the proportion of the alkyl (meth)acrylate A1 may be, for example, approximately 65% by weight or more, approximately 75% by weight or more, or approximately 80% by weight or more. In some other embodiments, the proportion of the alkyl (meth)acrylate A1 may be, for example, approximately 85% by weight or more, approximately 90% by weight or more, or approximately 95% by weight or more. The upper limit of the ratio of the alkyl (meth)acrylate A1 in the monomer raw material is not particularly limited, and it is usually suitable to be 99.5% by weight or less, for example, it can be 99% by weight or less. In some embodiments, for example, in the pressure-sensitive adhesive layer comprising a polymer having a carbon-carbon double bond, from the viewpoint of preferably expressing the action of the carbon-carbon double bond, the alkyl ( The proportion of meth)acrylate A1 is preferably approximately 95% by weight or less, more preferably approximately 90% by weight or less, may be approximately 85% by weight or less, may be approximately 75% by weight or less, and may be approximately 70% by weight or less. may be

The proportion of the alkyl (meth) acrylate A1 in the total alkyl (meth) acrylate is suitably about 50 wt% or more, and from the viewpoint of preferably expressing the action of the alkyl (meth) acrylate A1, it is preferably about 70% by weight or more, more preferably approximately 80% by weight or more, may be approximately 90% by weight or more, may be approximately 95% by weight or more, or may be approximately 99% by weight or more. The upper limit of the ratio of the alkyl (meth)acrylate A1 to the whole alkyl (meth)acrylate is 100 weight%.

In some embodiments, the alkyl (meth) acrylate A1 may include one or more alkyl (meth) acrylates A3 having an alkyl group having less than 7 carbon atoms at the ester terminal thereof. A pressure-sensitive adhesive containing a polymer obtained from a monomer raw material containing alkyl (meth)acrylate A3 is easy to provide a pressure-sensitive adhesive sheet that is efficiently peeled off by a peeling method in which a peeling solution such as water is supplied to a peeling wire from an adherend. Moreover, in the active energy ray-curable adhesive containing the polymer obtained from the monomer raw material containing alkyl (meth)acrylate A3, the hardening reaction by irradiation of an active energy ray can advance suitably. From such a viewpoint, the number of carbon atoms of the alkyl group in the alkyl (meth)acrylate A3 is preferably 6 or less, more preferably 4 or less, and may be 3 or less or 2 or less. Moreover, 1 or more may be sufficient as the carbon atom number of the alkyl group in alkyl (meth)acrylate A3, and it is preferable that it is 2 or more from a viewpoint of adhesiveness with respect to a to-be-adhered body.

In the aspect in which the said monomer raw material contains alkyl (meth)acrylate A3, the ratio of the alkyl (meth)acrylate A3 to the whole monomer raw material may be, for example, about 1 weight% or more, and is usually about It is suitably 5 wt% or more, and from the viewpoint of preferably expressing the action of the alkyl (meth)acrylate A3, preferably about 20 wt% or more, more preferably about 30 wt% or more, still more preferably about 40 wt% or more. % by weight or more, particularly preferably about 50% by weight or more, for example, may be 60% by weight or more, may be approximately 70% by weight or more, may be approximately 80% by weight or more, or may be approximately 90% by weight or more. The upper limit of the ratio of the alkyl (meth)acrylate A3 to the whole monomer raw material is not specifically limited, Usually, it is suitable to set it as about 99 weight% or less, for example, it can be set as 90 weight% or less. In some embodiments, for example, in the pressure-sensitive adhesive layer comprising a polymer having a carbon-carbon double bond, from the viewpoint of preferably expressing the action of the carbon-carbon double bond, alkyl (meth ) The proportion of acrylate A3 is preferably about 80% by weight or less, more preferably about 70% by weight or less, still more preferably about 60% by weight or less. The above aspect may be, for example, an aspect in which a reactive group for curing treatment or a functional group serving as a crosslinking point is introduced into the polymer.

The proportion of the alkyl (meth) acrylate A3 in the total alkyl (meth) acrylate is suitably about 5 wt% or more, and from the viewpoint of preferably expressing the action of the alkyl (meth) acrylate A3, it is preferably about 20% by weight or more, more preferably about 35% by weight or more, still more preferably about 45% by weight or more, particularly preferably about 55% by weight or more, for example about 65% by weight or more, and about 75% by weight or more. % or more may be sufficient, about 85 weight% or more may be sufficient, and about 90 weight% or more may be sufficient. The upper limit of the ratio of the alkyl (meth)acrylate A3 to the whole said alkyl (meth)acrylate is 100 weight%, and is good also as about 98 weight% or less, for example. In some embodiments, for example, when using an alkyl (meth) acrylate A2 described later in combination with an alkyl (meth) acrylate A3, from the viewpoint of preferably expressing the action, the alkyl (meth) acrylate The proportion of the alkyl (meth)acrylate A3 in the whole may be, for example, approximately 90% by weight or less, approximately 85% by weight or less, approximately 75% by weight or less, approximately 60% by weight or less, and approximately 45 weight% or less may be sufficient, about 30 weight% or less may be sufficient, and about 15 weight% or less may be sufficient. It is not necessary to use the alkyl (meth)acrylate A3.

In some embodiments, the alkyl (meth) acrylate is an alkyl (meth) acrylate A2 having an alkyl group having 7 or more carbon atoms at the ester terminal, as the alkyl (meth) acrylate A1, or an alkyl (meth) It can be included as a monomer different from the acrylate A1. Using the alkyl (meth)acrylate A2 can be advantageous, for example, from the viewpoint of adhesion to an adherend. The number of carbon atoms of the alkyl group in the alkyl (meth)acrylate A2 is preferably 8 or more, and may be 9 or more. In addition, from the viewpoint of adhesive properties such as adhesive strength, the number of carbon atoms in the alkyl group in the alkyl (meth)acrylate A2 is preferably 14 or less, more preferably 12 or less, still more preferably 10 or less, For example, it is 9 or less, and may be less than 9.

In the aspect in which the said monomer raw material contains alkyl (meth)acrylate A2, the ratio of the alkyl (meth)acrylate A2 to the whole monomer raw material may be, for example, about 1 weight% or more, and is usually about It is suitable that it is 5 wt% or more, and from the viewpoint of more favorably expressing the action of the alkyl (meth)acrylate A2, it is preferably about 20 wt% or more, more preferably about 30 wt% or more, still more preferably about 40% by weight or more, particularly preferably about 50% by weight or more, for example, may be 60% by weight or more, may be approximately 70% by weight or more, may be approximately 80% by weight or more, or may be approximately 90% by weight or more. The upper limit of the ratio of the alkyl (meth)acrylate A2 to the whole of the monomer raw material is not particularly limited, and it is usually suitable to be set to about 99.5 wt% or less, for example, it can be set to about 99 wt% or less. In some embodiments, for example, in the pressure-sensitive adhesive layer comprising a polymer having a carbon-carbon double bond, from the viewpoint of preferably expressing the action of the carbon-carbon double bond, the alkyl ( The proportion of meth)acrylate A2 is preferably approximately 95% by weight or less, approximately 90% by weight or less, approximately 85% by weight or less, approximately 75% by weight or less, or approximately 70% by weight or less. .

The ratio of the alkyl (meth) acrylate A2 to the total alkyl (meth) acrylate contained in the monomer raw material is suitably about 5 wt % or more, and from the viewpoint of favorably expressing the action of the alkyl (meth) acrylate A2 preferably at least about 20 wt%, more preferably at least about 35 wt%, still more preferably at least about 45 wt%, for example at least about 55 wt%, or at least about 65 wt% , may be approximately 75% by weight or more, approximately 85% by weight or more, approximately 90% by weight or more, or approximately 95% by weight or more. The upper limit of the ratio of the alkyl (meth)acrylate A2 to the entire alkyl (meth)acrylate is 100% by weight. In some embodiments, for example, in the case of using alkyl (meth) acrylate A3 in combination with alkyl (meth) acrylate A2, from the viewpoint of preferably expressing the action, in the entire alkyl (meth) acrylate The proportion of the alkyl (meth)acrylate A2 occupied is, for example, approximately 95% by weight or less, approximately 90% by weight or less, approximately 80% by weight or less, approximately 70% by weight or less, or approximately 60% by weight. % or less, approximately 45 weight% or less, approximately 30 weight% or less, approximately 20 weight% or less, approximately 10 weight% or less, or approximately 5 weight% or less. It is not necessary to use the alkyl (meth)acrylate A2.

The monomer raw material used for the synthesis of the acrylic polymer may further include a parent monomer having copolymerizability with the alkyl (meth)acrylate as described above. The parent monomer may be helpful to introduce a crosslinking point to the acrylic polymer or to increase the cohesive force of the acrylic polymer. In addition, for example, in the monomer raw material used for the synthesis of a polymer having a carbon-carbon double bond, a functional group capable of reacting with a functional group (hereinafter also referred to as "functional group B") of a carbon-carbon double bond-containing monomer described later ( Hereinafter, it is preferable to employ|adopt the monomer which has a "functional group A") as a parent monomer.

As a parent monomer, the following functional group containing monomers can be used individually by 1 type or in combination of 2 or more type, for example.

Hydroxyl group-containing monomer: For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate , hydroxyalkyl (meth)acrylates such as (4-hydroxymethylcyclohexyl)methyl (meth)acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; Ether compounds, such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

Carboxylic group-containing monomer: For example, ethylenically unsaturated monocarboxylic acids, such as acrylic acid (AA), methacrylic acid (MAA), a crotonic acid, and isocrotonic acid; Ethylenically unsaturated dicarboxylic acids, such as maleic acid, a fumaric acid, itaconic acid, and a citraconic acid.

Acid anhydride group-containing monomers: for example, maleic anhydride and itaconic anhydride.

Monomers having a nitrogen atom-containing ring: for example N-vinyl-2-pyrrolidone, methyl-N-vinylpyrrolidone, vinylpyridine, vinylpyrazine, vinylpyrimidine, N-vinylpiperidone, N-vinylpiperidone Razine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1 ,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisooxazole, N-vinylthiazole, N-vinylisothiazole, N-( meth)acryloylmorpholine, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine and the like.

Amide group-containing monomer: For example, (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N, N,N-dialkyl (meth)acrylamide, such as N-di(n-butyl)(meth)acrylamide and N,N-di(t-butyl)(meth)acrylamide; N-alkyl (meth)acrylamide, such as N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; N-vinyl carboxylic acid amides, such as N-vinyl acetamide; Monomers having a hydroxyl group and an amide group, for example, N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl) (meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide , N-hydroxyalkyl (meth)acrylamide, such as N-(4-hydroxybutyl) (meth)acrylamide; Monomers having an alkoxy group and an amide group, for example, N-alkoxyalkyl (such as N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide) meth)acrylamide; N,N-dialkylaminoalkyl (meth)acrylamide, such as N,N-dimethylaminopropyl (meth)acrylamide, etc.;

Amino group-containing monomers: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.

Monomers having a succinimide skeleton: for example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryl Royl-8-oxyhexamethylenesuccinimide and the like.

Maleimides: For example, N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide, etc.

Itaconimides: For example, N-methylitaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itacon mide, N-cyclohexyl itaconimide, N-lauril itaconimide, and the like.

Epoxy group-containing monomers: For example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.

Cyano group-containing monomers: for example, acrylonitrile, methacrylonitrile.

Keto group-containing monomers: for example, diacetone (meth) acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate.

Alkoxysilyl group-containing monomer: for example, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3- Alkoxysilyl group-containing (meth)acrylates, such as (meth)acryloxypropylmethyldiethoxysilane, alkoxysilyl group-containing vinyl compounds, such as vinyl trimethoxysilane and vinyl triethoxysilane, etc.

Amino group-containing monomers: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.

A monomer having an epoxy group: For example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.

Monomers containing a sulfonic acid group or a phosphoric acid group: For example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloylphosphate, and the like.

Isocyanate group-containing monomers: for example, 2-isocyanatoethyl (meth)acrylate, (meth)acryloyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate.

The amount of the functional group-containing monomer may be appropriately selected so as to realize a desired cohesive force, and is not particularly limited. Usually, from the viewpoint of making cohesive force and other properties (eg, adhesiveness) compatible in good balance, the amount of the functional group-containing monomer (when two or more kinds of functional group-containing monomers are used, their total amount) is usually the monomer. It is suitable to set it as 0.1 weight% or more of the whole raw material, Preferably it is 0.3 weight% or more, for example, 1 weight% or more. In addition, the amount of the functional group-containing monomer may be, for example, 50 wt% or less of the whole monomer raw material, preferably 40 wt% or less, for example, 35 wt% or less, 30 wt% or less, 25 wt% or less may be sufficient, and 20 weight% or less may be sufficient as it.

In some embodiments, the monomer raw material may include a hydroxyl group-containing monomer as the functional group-containing monomer. The amount used in the case of using a hydroxyl-containing monomer is not particularly limited, and for example, may be 0.01 wt% or more, 0.1 wt% or more, 0.5 wt% or more, or 1 wt% of the whole monomer raw material. or more may be sufficient, 5 weight% or more, or 10 weight% or more may be sufficient. In some embodiments, the amount of the hydroxyl group-containing monomer to be used can be, for example, 50% by weight or less of the entire monomer raw material, and from the viewpoint of suppressing the absorption of the pressure-sensitive adhesive, it is usually suitable to be 40% by weight or less. , may be 30% by weight or less, may be 25% by weight or less, or may be 20% by weight or less. Moreover, in some aspects, the usage-amount of a hydroxyl-containing monomer is good also as 15 weight% or less of the whole monomer raw material, good also as 10 weight% or less, and good also as 5 weight% or less. Alternatively, it is not necessary to use a hydroxyl group-containing monomer.

In some embodiments, the monomer raw material may include a carboxyl group-containing monomer as the functional group-containing monomer. The ratio of the carboxyl group-containing monomer in the whole monomer raw material used for the synthesis of the acrylic polymer may be, for example, 15% by weight or less, or 10% by weight or less, from the viewpoint of suppression of absorption of the pressure-sensitive adhesive layer during wafer processing It is preferably 7 wt% or less, 5 wt% or less, 3 wt% or less, 2 wt% or less, 1 wt% or less, 0.5 wt% or less, or 0.1 wt% or less . The monomer raw material does not need to contain a carboxyl group-containing monomer substantially. Here, the fact that the carboxyl group-containing monomer is not substantially contained means that the carboxyl group-containing monomer is not used at least intentionally. For example, in the monomer raw material used for preparation of the polymer which has a carbon-carbon double bond in a side chain, the structure in which the ratio of a carboxyl group monomer was restrict|limited as mentioned above is employable preferably.

In some embodiments, the monomer raw material may include a monomer having a nitrogen atom as the functional group-containing monomer. By use of the monomer which has a nitrogen atom, moderate polarity can be provided to an adhesive. This can be advantageous for realization of a pressure-sensitive adhesive sheet suitable for light peeling by supplying an aqueous peeling solution such as water. As one preferred example of the monomer having a nitrogen atom, a monomer having a nitrogen atom-containing ring is exemplified. Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-type compounds (such as N-vinyl cyclic amide) and N-(meth)acryloyl, such as N-vinyl-2-pyrrolidone, from the viewpoint of compatibility and the like. An N-(meth)acryloyl type compound, such as ilmorpholine, can be employ|adopted preferably.

The amount used in the case of using a monomer having a nitrogen atom is not particularly limited, and for example, may be 1 wt% or more, 2 wt% or more, 3 wt% or more, 5 wt% or more of the whole monomer raw material. % or more may be sufficient, and 7 weight% or more may be sufficient as it. From a viewpoint of obtaining a higher effect, in some aspects, the usage-amount of the monomer which has a nitrogen atom may be 10 weight% or more of the whole monomer raw material, 15 weight% or more may be sufficient, and 20 weight% or more may be sufficient as it. In addition, from the viewpoint of facilitating the balance of characteristics, the amount of the monomer having a nitrogen atom to be used is usually, for example, 40% by weight or less of the entire monomer raw material, and may be 35% by weight or less, and 30% by weight or less. It is good also as weight% or less, and is good also as 25 weight% or less. In some embodiments, the amount of the monomer having a nitrogen atom to be used is, for example, 20 wt% or less, 15 wt% or less, 10 wt% or less, or 5 wt% or less of the whole monomer raw material. can be done with Alternatively, a monomer having a nitrogen atom may not be used.

When the monomer raw material is used for the preparation of a polymer having a carbon-carbon double bond, as a parent monomer, a functional group capable of reacting with a functional group (functional group B) of a compound having a carbon-carbon double bond described later (functional group A) It is preferable to use a functional group-containing monomer having In this case, the kind of the functional group-containing monomer is determined by the kind of the compound. As the parent monomer having the functional group A, for example, a hydroxyl group-containing monomer, a carboxy group-containing monomer, an epoxy group-containing monomer, and an isocyanate group-containing monomer are preferable, and a hydroxyl group-containing monomer is particularly preferable. By using a hydroxyl group-containing monomer as the parent monomer, the acrylic polymer has a hydroxyl group. In contrast, by using an isocyanate group-containing monomer as a compound having a carbon-carbon double bond, the hydroxyl group (functional group A) of the acrylic polymer and the isocyanate group (functional group B) of the compound react, and carbon-derived from the compound- A carbon double bond is introduced into the acrylic polymer.

In addition, when using the parent monomer for the purpose of reaction with a compound having a carbon-carbon double bond, the amount of the parent monomer (preferably a hydroxyl group-containing monomer) is, from the viewpoint of making it easy to obtain a pressure-sensitive adhesive layer suitable for water peeling. , It is suitably set to about 1 wt% or more of the total monomer raw material, preferably about 5 wt% or more, more preferably about 10 wt% or more, still more preferably about 12 wt% or more, for example about 14 wt% or more weight % or more. In addition, from the viewpoint of maintaining good adhesion properties such as adhesiveness, the amount of the parent monomer is suitably set to about 40% by weight or less of the total monomer raw materials, preferably about 30% by weight or less, more preferably It is about 20 weight% or less, for example, about 15 weight% or less may be sufficient.

The monomer raw material used for the preparation of the acrylic polymer may contain parent monomers (hereinafter also referred to as copolymerizable monomers) other than the functional group-containing monomers described above for the purpose of increasing the cohesive force of the acrylic polymer.

As a non-limiting example of the said copolymerizable monomer, the following are mentioned.

Alkoxy group-containing monomers: For example, alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, and 2-ethoxyethyl (meth)acrylate ( alkoxyalkyl (meth)acrylate); Alkoxy (poly) alkylene glycol (meth) acrylates, such as methoxy ethylene glycol (meth) acrylate, a methoxy polyethylene glycol (meth) acrylate, and a methoxy polypropylene glycol (meth) acrylate.

Vinyl esters: For example, vinyl acetate, vinyl propionate, etc.

Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compounds: For example, styrene, α-methylstyrene, vinyltoluene and the like.

Olefins: For example, ethylene, butadiene, isoprene, isobutylene, etc.

(meth)acrylic acid ester having an alicyclic hydrocarbon group: For example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (meth)acrylates containing an alicyclic hydrocarbon group such as damantyl (meth)acrylate.

Aromatic ring-containing (meth)acrylate: For example, aryl(meth)acrylate such as phenyl(meth)acrylate, aryloxyalkyl(meth)acrylate such as phenoxyethyl(meth)acrylate, benzyl(meth)acrylate ) arylalkyl (meth)acrylates such as acrylates.

In addition, heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylic acid, halogen atom-containing monomers such as vinyl chloride and fluorine atom-containing (meth)acrylate, and organo such as silicone (meth)acrylate (meth)acrylic acid esters obtained from siloxane chain-containing monomers, terpene compound derivative alcohols, and the like.

Such a copolymerizable monomer can be used individually by 1 type or in combination of 2 or more type. The amount of these other copolymerizable monomers may be appropriately selected depending on the purpose and use, and is not particularly limited, but for example, 20 wt% or less (for example, 2 to 20 wt%, typically 2 to 20 wt%) in the total monomer raw material of the acrylic polymer. 3 to 10% by weight) is preferable.

In a preferred embodiment, the monomer raw material, from the viewpoint of suppression of gelation, it is preferable that the total ratio of alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate is limited to less than 20% by weight. . The total ratio of the alkoxyalkyl (meth)acrylate and the alkoxypolyalkylene glycol (meth)acrylate is more preferably less than 10% by weight, still more preferably less than 3% by weight, particularly preferably less than 1% by weight. and, in one embodiment, the monomer raw material does not substantially include alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate (content 0 to 0.3% by weight).

Similarly, in one embodiment, the monomer raw material may include or not contain an alkoxy group-containing monomer in a ratio of less than 20 wt%. The amount of the alkoxy group-containing monomer in the monomer raw material is preferably less than 10 wt%, more preferably less than 3 wt%, still more preferably less than 1 wt%, and in a particularly preferred embodiment, the monomer raw material is alkoxy Substantially free from group-containing monomers (content 0 to 0.3% by weight).

The method for polymerizing the monomer raw material is not particularly limited, and various polymerization methods known as methods for synthesizing the acrylic polymer, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, can be appropriately employed. For example, a solution polymerization method can be preferably employed. As a monomer supply method at the time of solution polymerization, a batch injection system which supplies all the monomer raw materials at once, a continuous supply (dropping) system, a divided supply (dropping) system, etc. can be employ|adopted suitably. The solvent (polymerization solvent) used for solution polymerization can be suitably selected from conventionally well-known organic solvent. For example, aromatic compounds, such as toluene (typically aromatic hydrocarbons); esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1,2-dichloroethane; Lower alcohols, such as isopropyl alcohol (For example, C1-C4 monohydric alcohol); ethers such as tert-butyl methyl ether; Ketones, such as methyl ethyl ketone; Any 1 type of solvent selected from etc., or 2 or more types of mixed solvent can be used. The polymerization temperature can be appropriately selected according to the type of the monomer and solvent to be used, the type of the polymerization initiator, and the like, and can be, for example, about 20°C to 120°C (typically 40°C to 80°C). According to the solution polymerization, a polymerization reaction solution in the form in which a polymer of a monomer raw material is dissolved in a polymerization solvent is obtained. The pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer can be preferably prepared using the polymerization reaction solution. The preparation of the pressure-sensitive adhesive composition using the polymerization reaction solution may include, for example, chemical modification such as introduction of a carbon-carbon double bond to the polymer included in the polymerization reaction solution.

In superposition|polymerization, a well-known or customary thermal polymerization initiator and a photoinitiator can be used according to a polymerization method, a polymerization aspect, etc. Examples of the thermal polymerization initiator may include an azo polymerization initiator, a peroxide initiator, a redox initiator using a combination of a peroxide and a reducing agent, a substituted ethane initiator, and the like. Examples of the photopolymerization initiator include α-ketol-based photoinitiator, acetophenone-based photoinitiator, benzoin ether-based photoinitiator, ketal-based photoinitiator, aromatic sulfonylchloride-based photoinitiator, photoactive oxime-based photoinitiator, and benzophenone-based photoinitiator. A photoinitiator, a thioxanthone type photoinitiator, an acyl phosphinoxide type photoinitiator, etc. are mentioned. A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

The usage-amount of a polymerization initiator may just be a normal usage-amount, For example, it can select in the range of about 0.005-1 weight part (typically 0.01-1 weight part) with respect to 100 weight part of total monomer raw materials. In addition, when using a polymerization initiator also as a photoinitiator, the usage-amount of a polymerization initiator can be set taking it into consideration.

For the polymerization, if necessary, various conventionally known chain transfer agents (which may also be regarded as molecular weight regulators or polymerization degree regulators) can be used. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid and α-thioglycerol can be used. Alternatively, a chain transfer agent containing no sulfur atom (non-sulfur chain transfer agent) may be used. Specific examples of the non-sulfur chain transfer agent include anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenoids such as α-pinene and terpinolene; styrenes such as α-methylstyrene and α-methylstyrene dimer; compounds having a benzylidenyl group such as dibenzylideneacetone, cinnamyl alcohol, and cinnamylaldehyde; hydroquinones such as hydroquinone and naphthohydroquinone; quinones such as benzoquinone and naphthoquinone; olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol, and allyl alcohol; benzyl hydrogens such as diphenylbenzene and triphenylbenzene; and the like.

A chain transfer agent can be used individually by 1 type or in combination of 2 or more type. When using a chain transfer agent, the usage-amount can be made into about 0.01-1 weight part about with respect to 100 weight part of monomer raw materials, for example. The technique disclosed herein can be preferably implemented even in an embodiment in which a chain transfer agent is not used.

The molecular weight of the acrylic polymer is not particularly limited and may be set in an appropriate range according to the required performance. The weight average molecular weight (Mw) of the acrylic polymer is usually about 10 × 10 ⁴ or more (for example, 20 × 10 ^{4 or more), and is more than 30 × 10 4} from the viewpoint of achieving both cohesive force and adhesive force in good balance. It is suitable, and it ^{is preferably about 40×10 4} or more, and may be about 50×10 ⁴ or more, and may be about 55×10 ⁴ or more. The upper limit of Mw of an acrylic polymer is not specifically limited. From a viewpoint of the coatability of an adhesive composition, ^{it is suitable that Mw of an acrylic polymer is usually about 500 x 10 4} or less, for example, about 150 x 10 ⁴ or less may be sufficient, and about 75 x 10 ⁴ or less may be sufficient as it. Said Mw may be Mw of the acrylic polymer in any in an adhesive layer in an adhesive composition.

Here, Mw means the value in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As a GPC apparatus, model name "HLC-8320GPC" (column: TSKgelGMH-H(S), Tosoh Corporation make) can be used, for example. It is the same also in the Example mentioned later.

The acrylic adhesive layer may further contain polymers other than an acrylic polymer as a subpolymer as needed. Preferred examples of the subpolymer include those other than the acrylic polymer among the various polymers exemplified as polymers that can be included in the pressure-sensitive adhesive layer. When the pressure-sensitive adhesive layer disclosed herein is an acrylic pressure-sensitive adhesive layer containing a subpolymer in addition to the acrylic polymer, the content of the subpolymer is suitably less than 100 parts by weight based on 100 parts by weight of the acrylic polymer, and 50 parts by weight. The following is preferable, 30 weight part or less is more preferable, and 10 weight part or less is still more preferable. The content of the subpolymer may be 5 parts by weight or less or 1 part by weight or less with respect to 100 parts by weight of the acrylic polymer. The technique disclosed herein can be preferably implemented in an embodiment in which 99.5 to 100% by weight of the polymer contained in the pressure-sensitive adhesive layer is an acrylic polymer.

(Adhesive layer other than acrylic type)

In the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface may be a pressure-sensitive adhesive layer using a polymer other than an acrylic polymer as a base polymer, that is, an adhesive layer other than an acryl-type pressure-sensitive adhesive layer. In addition to the base polymer, the adhesive layer other than an acryl type may further contain subpolymers other than the base polymer as needed. In this case, content of the subpolymer in the adhesive layer other than an acrylic type can be selected from the said content illustrated as content of the subpolymer in an acrylic adhesive layer. The pressure-sensitive adhesive layer other than the acrylic may be a pressure-sensitive adhesive layer containing an acrylic polymer as a subpolymer.

(Glass Transition Temperature)

It is preferable that the glass transition temperature (Tg) of the base polymer (for example, acrylic polymer) of the adhesive layer which comprises an adhesive surface is 15 degrees C or less. In some embodiments, the Tg is preferably 10°C or less, preferably 0°C or less, from the viewpoint of adhesion to an adherend (for example, followability to the surface shape of the adherend) and the like, and -10 C or lower may be sufficient, and -20 deg. C or lower may be sufficient. In addition, from the viewpoint of the cohesiveness of the pressure-sensitive adhesive or the ease of light peeling by water peeling, the Tg of the base polymer may be, for example, -75°C or higher, -60°C or higher, or -50°C or higher. Some aspects WHEREIN: Tg of a base polymer may be -45 degreeC or more, and -40 degreeC or more may be sufficient as it.

Here, the glass transition temperature (Tg) of a polymer in this specification means the glass transition temperature calculated|required by the formula of Fox based on the composition of the monomer raw material which comprises the polymer. The expression of Fox is a relational expression between Tg of the copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.

1/Tg = Σ(Wi/Tgi)

In addition, in the formula of Fox, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on weight), Tgi is the homo of the monomer i The glass transition temperature (unit: K) of the polymer is shown.

As the glass transition temperature of the homopolymer used for calculation of Tg, the value described in known materials shall be used. For example, for the monomers illustrated below, the following values are used as the glass transition temperature of the homopolymer of the monomer.

2-ethylhexyl acrylate -70 ℃

n-Butyl acrylate -55 ℃

Isostearyl acrylate -18 ℃

Methyl methacrylate 105 °C

Methyl acrylate 8 °C

N-vinyl-2-pyrrolidone 54 °C

N-acryloylmorpholine 145 °C

2-hydroxyethyl acrylate -15 °C

4-hydroxybutyl acrylate -40 ℃

Acrylic acid 106 ℃

methacrylic acid 228 ℃

For glass transition temperatures of homopolymers of monomers other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd ed., John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value is employed.

For monomers for which the glass transition temperature of the homopolymer is not described in the Polymer Handbook, a value obtained by the following measurement method is used (see Japanese Patent Application Laid-Open No. 2007-51271). Specifically, 100 parts by weight of a monomer, 0.2 parts by weight of azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as a polymerization solvent were introduced into a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux cooling tube, and nitrogen gas was introduced into the reactor. Agitate for 1 hour while circulating. After removing oxygen in a polymerization system in this way, it heats up at 63 degreeC and makes it react for 10 hours. Then, it cools to room temperature, and obtains the homopolymer solution with a solid content concentration of 33 weight%. Next, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 2 mm. This test sample is punched out in the shape of a disk with a diameter of 7.9 mm, inserted into a parallel plate, and subjected to shear deformation at a frequency of 1 Hz using a viscoelasticity tester (ARES, manufactured by Rheometrics) in a temperature range of -70 to 150°C. , the viscoelasticity is measured in shear mode at a temperature increase rate of 5°C/min, and the peak top temperature of tan δ is taken as Tg of the homopolymer.

(Surfactants)

In some preferred embodiments, the pressure-sensitive adhesive layer may include a surfactant. According to the adhesive layer containing surfactant, the fall effect of the peeling force by supplying an aqueous peeling liquid to the peeling interface with a to-be-adhered body can be expressed suitably. Although the reason is not specifically limited analysis, Surfactant has a hydrophilic area|region, and by it, it is unevenly distributed on the surface of an adhesive layer, and when contacting with an aqueous peeling liquid, it is thought that peeling force is effectively reduced. As the surfactant, one type or two or more types of known surfactants can be used without particular limitation. It is preferable that surfactant is typically contained in an adhesive layer in a free form. As surfactant, a liquid thing at normal temperature (about 25 degreeC) is used preferably from the point of adhesive composition preparation property.

HLB of surfactant is not specifically limited. The HLB of the surfactant may be, for example, 1 or more or 3 or more. It is preferable that HLB of surfactant may be 5 or more, 6 or more may be sufficient as it, 8 or more may be sufficient, and 9 or more may be sufficient as it. Thereby, there exists a tendency for water releasability to express favorably. The HLB of the surfactant is more preferably 10 or more, still more preferably 11 or more, still more preferably 12 or more, particularly preferably 13 or more, and may be 14 or more, 15 or more, and further 16 or more. do. According to the surfactant which has HLB of the said range, the light-peelability by water peeling can be expressed more effectively. The upper limit of the said HLB is 20 or less, for example, 18 or less may be sufficient. In some aspects, for example, from a compatibility viewpoint, HLB of surfactant may be 16 or less, for example, 15 or less may be sufficient as it.

In addition, HLB in this specification is a Hydrophile-Lipophile Balance by Griffin, it is a value which shows the degree of affinity for water and oil of a surfactant, and the ratio of hydrophilicity and lipophilicity is expressed with a numerical value between 0-20. will be. HLB is defined by W. C. Griffin: J. Soc. Cosmetic Chemists, 1,311 (1949) Na, Koshitami Takahashi, Yoshiro Namba, Motoo Koike, and Masao Kobayashi, "Surfactant Handbook", 3rd edition, published by Kogaku Books, November 25, Showa 47, p179 to 182 and the like. The surfactant having HLB can be selected based on the technical common knowledge of those skilled in the art, for example, taking into consideration the aforementioned references as necessary.

As surfactant, well-known nonionic surfactant, anionic surfactant, cationic surfactant, etc. can be used. Especially, nonionic surfactant is preferable. Surfactant can be used individually by 1 type or in combination of 2 or more type.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; polyoxyethylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate, and polyoxyethylene monooleate; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, and sorbitan monooleate; Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan triisostearate, polyoxyethylene sorbate polyoxyethylene sorbitan fatty acid esters such as bitan monooleate and polyoxyethylene sorbitan trioleate; polyoxyethylene glyceryl ether fatty acid ester; polyoxyethylene-polyoxypropylene block copolymers; and the like. The nonionic surfactant is a reactive surfactant having a radically polymerizable functional group such as a propenyl group, a (meth)allyl group, a vinyl group, and a (meth)acryloyl group (for example, polyoxyethylene nonylpropenylphenyl ether, etc.) , a nonionic reactive surfactant). These nonionic surfactants can be used individually by 1 type or in combination of 2 or more type. From viewpoints of performance stability of an adhesive sheet, etc., the (non-reactive) nonionic surfactant which does not have the above-mentioned radically polymerizable functional group can be employ|adopted preferably.

Examples of the anionic surfactant include alkyl sulfates such as lauryl sulfate and octadecyl sulfate; fatty acid salts; Alkylbenzenesulfonates, such as a nonylbenzenesulfonate and a dodecylbenzenesulfonate; naphthalenesulfonates such as dodecylnaphthalenesulfonate; Alkyl diphenyl ether disulfonate, such as a dodecyl diphenyl ether disulfonate; polyoxyethylene alkyl ether sulfates such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate; polyoxyethylene alkylphenyl ether sulfates such as polyoxyethylene lauryl phenyl ether sulfate; polyoxyethylene styrenated phenyl ether sulfate; sulfosuccinates such as lauryl sulfosuccinate and polyoxyethylene lauryl sulfosuccinate; polyoxyethylene alkyl ether phosphate; polyoxyethylene alkyl ether acetate; and the like. When the anionic surfactant forms a salt, the salt may be, for example, a metal salt (preferably a monovalent metal salt) such as a sodium salt, a potassium salt, a calcium salt, or a magnesium salt, an ammonium salt, an amine salt, or the like. have. These anionic surfactants can be used individually by 1 type or in combination of 2 or more type.

The usage-amount of surfactant is not specifically limited, It can set so that the peeling force fall by supply of an aqueous peeling liquid may express effectively. In some embodiments, the amount of the surfactant used may be, for example, about 5 parts by weight or less with respect to 100 parts by weight of the base polymer, and from the viewpoint of bonding reliability to the adherend, it is suitable to be about 3 parts by weight or less. and preferably less than 2 parts by weight, more preferably less than 1 part by weight, may be less than 0.8 parts by weight, may be less than 0.6 parts by weight, may be less than 0.4 parts by weight, may be less than 0.2 parts by weight, may be less than 0.1 parts by weight It may be less than a part. A surfactant with a high HLB (eg, 5 or more) tends to exhibit good water releasability even when added in a small amount. In addition, from the viewpoint of exhibiting the effect of adding the surfactant, in some embodiments, the amount of the surfactant relative to 100 parts by weight of the base polymer can be, for example, 0.001 parts by weight or more, and by supplying the aqueous stripper From a viewpoint of expressing the peeling force lowering effect with better uniformity, it is usually suitable to set it as 0.01 weight part or more, Preferably it is 0.03 weight part or more (for example, 0.1 weight part or more). In a composition that emphasizes water releasability, the amount of the surfactant relative to 100 parts by weight of the base polymer may be 0.3 parts by weight or more (eg, 0.5 parts by weight or more).

(crosslinking agent)

For the pressure-sensitive adhesive layer (which may be an active energy ray-curable pressure-sensitive adhesive layer), a crosslinking agent may be used as needed for the purpose of adjusting cohesive force or the like. A crosslinking agent may be contained in an adhesive layer in the form after a crosslinking reaction, and may be contained in the form before a crosslinking reaction. The type of the crosslinking agent is not particularly limited, and among conventionally known crosslinking agents, for example, depending on the composition of the pressure-sensitive adhesive composition, the crosslinking agent may be selected so as to exhibit an appropriate crosslinking function in the pressure-sensitive adhesive layer. Examples of the crosslinking agent that can be used include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide-based crosslinking agent, a melamine-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, and a metal salt. A crosslinking agent, a hydrazine type crosslinking agent, an amine type crosslinking agent, etc. can be illustrated. These can be used individually by 1 type or in combination of 2 or more type. In some preferred embodiments, at least an isocyanate-based crosslinking agent is used as the crosslinking agent. You may use combining an isocyanate type crosslinking agent and another crosslinking agent (for example, an epoxy type crosslinking agent).

As an isocyanate-type crosslinking agent, the polyfunctional isocyanate compound more than bifunctional can be used. For example, Aromatic isocyanate, such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris (p-isocyanatophenyl) thiophosphate, and diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; Aliphatic isocyanate, such as hexamethylene diisocyanate; and the like. As a commercial item, Trimethylolpropane/tolylene diisocyanate trimer adduct (Tosoh Corporation make, brand name "Colonate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (Tosoh Corporation make, brand name "Colonate HL") ') and isocyanate adducts such as isocyanurate forms of hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade name "Colonate HX"), etc. can be illustrated.

As the epoxy-based crosslinking agent, those having two or more epoxy groups in one molecule can be used without particular limitation. The epoxy-type crosslinking agent which has 3-5 epoxy groups in 1 molecule is preferable. Specific examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc. are mentioned. Commercially available epoxy crosslinking agents include "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi Gas Chemical, "Epiclon CR-5L" manufactured by DIC, and "Denacol EX" manufactured by Nagase Chemtex. -512", the Nissan Chemical Industry Co., Ltd. brand name "TEPIC-G", etc. are mentioned.

As the oxazoline-based crosslinking agent, one having at least one oxazoline group in one molecule may be used without particular limitation.

Examples of the aziridine-based crosslinking agent include trimethylolpropanetris[3-(1-aziridinyl)propionate], trimethylolpropanetris[3-(1-(2-methyl)aziridinylpropionate)], etc. can be heard

As the carbodiimide-based crosslinking agent, a low-molecular compound or a high-molecular compound having two or more carbodiimide groups can be used.

The metal chelate-based crosslinking agent may typically have a structure in which a polyvalent metal is covalently bonded or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Ba, Mo, La, Sn, Ti, and the like. Especially, Al, Zr, and Ti are preferable. Examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound. The metal chelate-based crosslinking agent may be typically a compound having a structure in which an oxygen atom in the organic compound is bonded to the polyvalent metal (covalent bond or coordination bond).

In some embodiments, a peroxide may be used as the crosslinking agent. Examples of the peroxide include di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t- Hexyl peroxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, dibenzoyl peroxide, etc. can be heard Among these, di(4-t-butylcyclohexyl)peroxydicarbonate, dilauroyl peroxide, dibenzoyl peroxide, etc. are mentioned as a peroxide especially excellent in crosslinking reaction efficiency. In addition, when a peroxide is used as the polymerization initiator, it is also possible to use the peroxide remaining without being used in the polymerization reaction for the crosslinking reaction. In that case, the residual amount of the peroxide is quantified, and when the ratio of the peroxide does not reach the predetermined amount, if necessary, the peroxide may be added so as to become a predetermined amount. Quantification of the peroxide can be performed by the method described in Japanese Patent No. 4971517.

The usage-amount of a crosslinking agent (when using two or more crosslinking agents, their total amount) is not specifically limited, It can set suitably so that the desired use effect may be acquired. From the viewpoint of adhesion to an adherend and bonding reliability during wafer (typically a semiconductor wafer) processing, the amount of the crosslinking agent to be used with respect to 100 parts by weight of the base polymer (eg, acrylic polymer) is usually about 15 parts by weight It is suitable to be less than or equal to about 12 parts by weight, preferably about 12 parts by weight or less, more preferably about 10 parts by weight or less, may be less than 7.0 parts by weight, may be less than 5.0 parts by weight, may be less than 4.0 parts by weight, may be 3.0 Less than a weight part may be sufficient, less than 2.0 weight part may be sufficient, and less than 1.0 weight part may be sufficient, and less than 0.5 weight part may be sufficient.

Further, for example, in the pressure-sensitive adhesive sheet having an adhesive surface constituted by an active energy ray-curable pressure-sensitive adhesive layer, from the viewpoint of exhibiting appropriate cohesiveness before curing treatment with an active energy ray, 100 weight of the base polymer (eg, acrylic polymer) The amount of the crosslinking agent to be used per part is usually preferably about 0.005 parts by weight or more, preferably about 0.01 parts by weight or more, may be about 0.05 parts by weight or more, may be about 0.1 parts by weight or more, and about 0.2 parts by weight or more. A weight part or more may be sufficient. In some embodiments, the amount of crosslinking agent used relative to 100 parts by weight of the base polymer is preferably greater than 0.3 parts by weight, more preferably greater than 0.5 parts by weight, greater than 1.0 parts by weight, or greater than 1.5 parts by weight, It may be more than 2.0 weight part, may exceed 3.0 weight part, and may exceed 4.0 weight part. In a pressure-sensitive adhesive sheet that can be used in an aspect in which water is peeled off after curing treatment with an active energy ray, when the amount of the cross-linking agent is increased, deformation due to curing shrinkage tends to be maintained until supply of the aqueous peeling solution, so that the water peeling method The effect of light peeling by application can be exhibited more favorably.

In the aspect of using an isocyanate-based crosslinking agent as a crosslinking agent, the amount of the isocyanate-based crosslinking agent used relative to 100 parts by weight of the base polymer is usually about 0.005 parts by weight or more from the viewpoint of exhibiting adequate cohesiveness before curing treatment, and , preferably about 0.01 parts by weight or more, about 0.05 parts by weight or more, about 0.1 parts by weight or more, about 0.2 parts by weight or more, more than 0.3 parts by weight, more than 0.5 parts by weight, 1.0 It may be more than a weight part, may exceed 1.5 weight part, may exceed 2.0 weight part, may exceed 3.0 weight part, and may exceed 4.0 weight part. In the pressure-sensitive adhesive sheet that can be used in an aspect in which water is peeled off after curing treatment with active energy rays, the effect of light peeling by application of the water peeling method can be better exhibited by increasing the amount of the isocyanate-based crosslinking agent used. have.

In addition, the usage-amount of an isocyanate-type crosslinking agent with respect to 100 weight part of base polymers is normally about 15 weight part or less, and it is suitable, and the adhesiveness and bonding to the to-be-adhered body at the time of wafer (typically a semiconductor wafer) processing. From a viewpoint of reliability etc., Preferably it is about 12 weight part or less, More preferably, it is about 10 weight part or less, may be less than 7.0 weight part, may be less than 5.0 weight part, may be less than 4.0 weight part, may be less than 4.0 weight part, 3.0 weight part Less than may be sufficient, less than 2.0 weight part may be sufficient, and less than 1.0 weight part may be sufficient, and less than 0.5 weight part may be sufficient.

In order to advance a crosslinking reaction more effectively, you may use a crosslinking catalyst. Examples of the cross-linking catalyst include metal-based cross-linking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, nashem ferric, butyl tin oxide, and dioctyl tin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyltin dilaurate are preferable. The amount of the crosslinking catalyst used is not particularly limited. The amount of the crosslinking catalyst used relative to 100 parts by weight of the base polymer may be, for example, approximately 0.0001 parts by weight or more and 1 part by weight or less, 0.001 parts by weight or more and 0.1 parts by weight or less, and 0.005 parts by weight or more and 0.5 parts by weight or less.

(polyfunctional monomer)

A polyfunctional monomer may be used for the adhesive layer as needed. A polyfunctional monomer may be used instead of or in combination with a crosslinking agent as described above, and may be helpful for purposes such as adjustment of cohesive force. As a polyfunctional monomer, the compound which has two or more carbon-carbon double bonds (For example, ethylenically unsaturated groups, such as a (meth)acryloyl group) can be used. The polyfunctional monomer may be contained in the pressure-sensitive adhesive layer in an unreacted form, or may be contained in the pressure-sensitive adhesive layer after the reaction (after crosslinking). The pressure-sensitive adhesive layer containing the unreacted polyfunctional monomer may be an active energy ray-curable pressure-sensitive adhesive layer capable of forming a crosslinked structure by reacting the polyfunctional monomer by irradiating the pressure-sensitive adhesive layer with active energy rays such as ultraviolet rays.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol Di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6 -Hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate , vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, hexyldiol di (meth)acrylate, and the like. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more type.

In the case of using the polyfunctional monomer, the appropriate amount to be used varies depending on the molecular weight, the number of functional groups, etc., but usually 0.01 part by weight to 3.0 parts by weight based on 100 parts by weight of the base polymer (eg, acrylic polymer). It is appropriate to set it to a certain range. In some embodiments, the amount of the polyfunctional monomer used relative to 100 parts by weight of the base polymer may be, for example, 0.02 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1.0 parts by weight or more, or 2.0 parts by weight or more. It may be more than There exists a tendency for higher cohesion force to be obtained by increase of the usage-amount of a polyfunctional monomer. On the other hand, from the viewpoint of avoiding a decrease in adhesion during wafer processing due to excessive cohesion improvement or a decrease in storage stability of the pressure-sensitive adhesive sheet, the amount of the polyfunctional monomer used relative to 100 parts by weight of the base polymer may be, for example, 10 parts by weight or less, 5.0 weight part or less may be sufficient and 3.0 weight part or less may be sufficient. Alternatively, a polyfunctional monomer may not be used. For example, the pressure-sensitive adhesive layer comprising a polymer having a structure (carbon-carbon double bond, benzophenone structure, etc.) that causes a crosslinking reaction upon irradiation with an active energy ray is substantially free of unreacted polyfunctional monomer. It may be a layer or a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition substantially free of a polyfunctional monomer. Here, that the pressure-sensitive adhesive composition substantially does not contain the polyfunctional monomer means that the amount of the polyfunctional monomer is less than 0.05 parts by weight (for example, less than 0.01 parts by weight) with respect to 100 parts by weight of the base polymer.

(Other optional ingredients)

To the pressure-sensitive adhesive layer (which may be an active energy ray-curable pressure-sensitive adhesive layer), if necessary, a tackifying resin (for example, a tackifying resin such as rosin-based, petroleum-based, terpene-based, phenol-based, or ketone-based), a viscosity modifier ( For example, thickeners), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, antioxidants, and various additives common in the field of pressure-sensitive adhesives, such as antioxidants, can be included as other optional components. have. As for such various additives, conventionally known ones can be used by a conventional method, and since the present invention is not particularly characterized, detailed description thereof is omitted.

From the viewpoint of achieving good balance between adhesion to an adherend during wafer processing and releasability upon removal from the adherend (eg, peelability due to water peeling), in some aspects, the pressure-sensitive adhesive The content of the tackifying resin in the layer may be, for example, less than 5 parts by weight, further less than 3 parts by weight, may be less than 1 part by weight, or less than 0.5 parts by weight with respect to 100 parts by weight of the base polymer. You may do it, and it is good also as less than 0.1 weight part. The adhesive layer which does not contain tackifying resin substantially (for example, content of the adhesive layer with respect to 100 weight part of base polymers is 0-0.05 weight part) may be sufficient. Thus, limiting content of tackifying resin may become advantageous also from a viewpoint of the sclerosis|hardenability improvement in an active energy ray-curable adhesive layer, for example.

In some preferred embodiments, the pressure-sensitive adhesive layer may have a composition in which the content of a polymer (typically a base polymer) accounts for approximately 80% by weight or more of the total weight of the pressure-sensitive adhesive layer. Thereby, the effect of applying water peeling to lower the peeling force (light peeling effect) can be realized preferably. From such a viewpoint, it is preferable that content of the said polymer is about 85 weight% or more of the total weight of an adhesive layer, It is more preferable that it is about 90 weight% or more, It may be about 92 weight% or more, and may be about 95 weight% or more. .

(Active energy ray-curable adhesive layer)

Some aspects WHEREIN: It is preferable that the adhesive layer which comprises an adhesive surface is the adhesive layer comprised with the active energy ray-curable adhesive (active energy ray-curable adhesive layer). The pressure-sensitive adhesive sheet having such a pressure-sensitive adhesive layer is irradiated with an active energy ray after sticking to an adherend to cure the active energy ray-curable pressure-sensitive adhesive layer, and then peeled by supplying an aqueous peeling solution such as water to the peeling wire from the adherend. By carrying out (water peeling), the peeling force from the said to-be-adhered body can be reduced especially effectively. As the reason, it is not interpreted particularly limitedly, but when an active energy ray is irradiated to an active energy ray-curable pressure-sensitive adhesive layer in a state affixed to an adherend, microscopic lifting from the adherend due to rapid curing shrinkage of the pressure-sensitive adhesive layer may occur. It is thought that when the aqueous peeling solution is supplied in this state, the penetration of the aqueous peeling solution into the interface between the adhesive layer and the adherend proceeds rapidly, and the peeling force is effectively reduced. do. By peeling the pressure-sensitive adhesive sheet configured such that the pressure-sensitive adhesive layer is cured by irradiation with an active energy ray and the peeling force is lowered by the water peeling method after irradiation with an active energy ray, a decrease in the peeling force due to curing of the pressure-sensitive adhesive layer and rapid curing described above Due to the synergistic effect of lowering the water peeling force due to shrinkage, a particularly remarkable light peeling effect can be exhibited.

In some aspects, it is preferable that an active energy ray-curable adhesive layer is comprised so that the peeling force from the said to-be-adhered body may fall compared with before irradiation by irradiating an active energy ray after sticking to an adherend and hardening. The pressure-sensitive adhesive sheet having such an active energy ray-curable pressure-sensitive adhesive layer has good bonding reliability to the adherend before irradiation with active energy rays, and remarkably reduces the peeling force by peeling with an aqueous peeling solution after irradiation with active energy rays. can

As one preferable example of an active energy ray-curable adhesive layer, what exhibits sclerosis|hardenability by including a carbon-carbon double bond in the adhesive layer is mentioned. The carbon-carbon double bond is chemically stable without reacting with moisture or acidity in the air in a typical storage environment that can be industrially applied. On the other hand, when radicals are generated by irradiating an active energy ray, it reacts (for example, a polymerization reaction or a crosslinking reaction) and hardens. As an active energy ray preferable from a viewpoint of handling easiness, etc., light (for example, ultraviolet-ray) is mentioned.

The adhesive layer which exhibits sclerosis|hardenability by including a carbon-carbon double bond WHEREIN: The existence form of the carbon-carbon double bond in this adhesive layer is not specifically limited. The carbon-carbon double bond is, for example, a polymer having a carbon-carbon double bond (eg, a base polymer) or a monomer having a carbon-carbon double bond (eg, unreacted as described above). polyfunctional monomer) and the like, and may be included in the pressure-sensitive adhesive layer. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The form of the carbon-carbon double bond contained in a polymer and the form of the carbon-carbon double bond contained in a monomer are not specifically limited. For example, carbon-carbon double bonds may be present in the polymer or monomer in the form of ethylenically unsaturated groups. Examples of the ethylenically unsaturated group include a (meth)acryloyl group, a vinyl group, an allyl group, and a methallyl group. A (meth)acryloyl group is preferable from a reactive viewpoint.

(Polymers with carbon-carbon double bonds)

Some aspects WHEREIN: It is preferable that an active-energy-ray-curable adhesive layer contains the polymer which has a carbon-carbon double bond. Hereinafter, a polymer having a carbon-carbon double bond is also referred to as a “polymer (PD)”. For example, polymers (PD) having a carbon-carbon double bond in the form of an ethylenically unsaturated group are preferred. In some preferred embodiments, the polymer (PD) may be contained in the active energy ray-curable pressure-sensitive adhesive layer as a base polymer of the pressure-sensitive adhesive layer. In some other aspects, the polymer (PD) may be included in the active energy ray-curable pressure-sensitive adhesive layer as a subcomponent used in addition to the carbon-carbon double bond-free base polymer. An active energy ray-curable pressure-sensitive adhesive layer containing a polymer (PD) as a base polymer and further containing a monomer having a carbon-carbon double bond (eg, unreacted polyfunctional monomer) as a subcomponent may be used.

The form of the carbon-carbon double bond which the polymer (PD) has is not specifically limited. The polymer which has a carbon-carbon double bond in a side chain may be sufficient as a polymer (PD), and the polymer which has in a principal chain may be sufficient as it. Here, having a carbon-carbon double bond in the main chain includes the presence of a carbon-carbon double bond in the main chain skeleton of the polymer (PD) and the presence of a carbon-carbon double bond at the end of the main chain. The polymer (PD) which has a carbon-carbon double bond in a side chain from a reactive viewpoint of a carbon-carbon double bond is employable preferably. A method for including a carbon-carbon double bond in the polymer (PD) is not particularly limited, and an appropriate method may be selected from methods known to those skilled in the art.

It does not specifically limit as a polymer (PD), A suitable polymer can be selected and used in consideration of the characteristic etc. of an adhesive layer. As the polymer (PD), a carbon-carbon double bond is introduced by a method such as chemical modification to a polymer (primary polymer) that does not contain a carbon-carbon double bond or has a small content of carbon-carbon double bond compared to the target product. One (secondary polymer) can be preferably used.

As a specific example of the method of introducing a carbon-carbon double bond into the primary polymer, a primary polymer in which a monomer having a functional group (functional group A) is copolymerized is prepared, and in the primary polymer, the functional group A and A method of reacting a compound having a reactive functional group (functional group B) and a carbon-carbon double bond (hereinafter also referred to as "functional group B-containing unsaturated compound") is reacted so that the carbon-carbon double bond is not lost. It is preferable that reaction of the functional group A and the functional group B is a reaction without radical generation|occurrence|production, such as a condensation reaction and an addition reaction.

Examples of the combination of the functional group A and the functional group B include a combination of a carboxy group and an epoxy group, a combination of a carboxy group and an aziridyl group, and a combination of a hydroxyl group and an isocyanate group. Especially, the combination of a hydroxyl group and an isocyanate group is preferable from a viewpoint of reaction traceability. In addition, if the combination of the functional groups A and B is a combination in which a polymer having a carbon-carbon double bond is obtained, one functional group in the combination may be referred to as a functional group A, and the other may be referred to as a functional group B, or The functional group may be referred to as a functional group B, and the other may be referred to as a functional group A. For example, if described with a combination of a hydroxyl group and an isocyanate group, the functional group A may be a hydroxyl group (in that case, the functional group B becomes an isocyanate group) or an isocyanate group (in that case, the functional group B becomes a hydroxyl group). Especially, the combination in which a primary polymer has a hydroxyl group and the said compound has an isocyanate group is preferable. This combination is particularly preferable when the primary polymer is an acrylic polymer.

In addition, a vinyl alcohol-based polymer (typically polyvinyl alcohol) is used as the primary polymer, and vinyl bromide or the like is added to the vinyl alcohol-based polymer (typically, a carbon-carbon double bond-free vinyl alcohol-based polymer). A method of reacting an allyl halide such as vinyl halide or allyl bromide is also mentioned as a preferred example of a method for obtaining a polymer having a carbon-carbon double bond. In this method, the said reaction is performed on suitable basic conditions, and the vinyl alcohol-type polymer containing a vinyl group in a side chain is obtained by the reaction. Moreover, you may employ|adopt the method of preparing the polymer which has a carbon-carbon double bond using the microorganism which produces a polymer as disclosed in Japanese Patent No. 4502363, for example. In this method, various conditions, such as the type of microorganism and the conditions for culturing microorganisms, may be set by adopting the conditions described in the above-mentioned patent publication or by appropriately modifying the conditions within the technical common sense of those skilled in the art.

The molar ratio (M _A / M _B) of the molar (M _A) and the molar (M _B) of the functional groups B of the functional group A is, in terms of both reactivity and typically is suitably not less than 0.2, and even 0.5 or more and 0.7 or more may be sufficient, and 1.0 or more may be sufficient as it. In some embodiments, the molar ratio is even greater than (M _A / M _B) is 1.0, and even greater than 1.5, or may be greater than 2.0. For example, in the case of using a functional group A on the other reaction (cross-linking reaction with a cross-linking agent, etc.), it is preferred that the molar ratio (M _A / M _B) to greater than 1.0. The molar ratio (M _A / M _B) may be, for example, 20 or less. In some aspects, the adhesiveness to the adherend before light irradiation and the peelability from the to-be-adhered body after light irradiation (for example, peelability by water peeling) are compatible in a good balance from a viewpoint, the molar ratio (M _a / M _B) is 10 or less and is even preferred, more than 5.0 that, and even more than 2.5, and even below 1.8, 1.5 or less is even.

Functional groups B and the carbon-amount (hereinafter also referred to as "functional group B-containing unsaturated compound") compound having a carbon-carbon double bond is in the range satisfying the above-mentioned molar ratio (M _A / M _B), 1 having a functional group A With respect to 100 parts by weight of the tea polymer, for example, it may be 1.0 parts by weight or more, may be 3.0 parts by weight or more, may be 5.0 parts by weight or more, or may be 7.0 parts by weight or more. From the viewpoint of making the adhesion before light irradiation and the releasability after light irradiation (eg, releasability by water peeling) compatible at a higher level, in some embodiments, functional group B-containing unsaturated unsaturated with respect to 100 parts by weight of the primary polymer The amount of the compound used is preferably 9.0 parts by weight or more, more preferably 10 parts by weight or more, and may be 12 parts by weight or more, 14 parts by weight or more, or 16 parts by weight or more. In addition, the amount of the functional group B-containing unsaturated compound used relative to 100 parts by weight of the primary polymer may be, for example, less than 40 parts by weight, and usually less than 35 parts by weight is suitable, and less than 30 parts by weight. It is preferable, and less than 25 weight part may be sufficient and less than 20 weight part may be sufficient. In some embodiments, the amount of the functional group B-containing unsaturated compound used relative to 100 parts by weight of the primary polymer may be less than 18 parts by weight, may be less than 16 parts by weight, may be less than 13 parts by weight, or may be less than 10 parts by weight. and less than 7 parts by weight may be sufficient.

As a preferable example of the polymer having a carbon-carbon double bond, for example, an acrylic polymer in which a (meth)acryloyl group is introduced into a side chain may be mentioned. Such an acrylic polymer is, for example, an acrylic primary polymer into which a hydroxyl group (functional group A) is introduced by copolymerization, and a compound having a carbon-carbon double bond and an isocyanate group (functional group B), wherein the carbon-carbon double bond is It can be obtained by making it react so as not to lose|disappear.

The polymer having a carbon-carbon double bond may be, for example, a diene-based polymer (typically a conjugated diene-based polymer). A diene-based polymer (typically a conjugated diene-based polymer) is a polymer obtained by polymerizing or copolymerizing a diene (typically a conjugated diene). Examples of the diene-based polymer (typically a conjugated diene-based polymer) include butadiene-based polymers such as polybutadiene and styrene-butadiene copolymer; isoprene-based polymers such as polyisoprene and styrene-isoprene copolymer; chloroprene-based polymers such as polychloroprene; and the like.

As another example of an active energy ray-curable adhesive layer, the adhesive layer containing the polymer which has structures other than a carbon-carbon double bond as a structure which raise|generates a crosslinking reaction by irradiation of an active energy ray is mentioned. For example, the adhesive containing the polymer which has a benzophenone structure in a side chain can express active energy ray sclerosis|hardenability by photocrosslinking using the said benzophenone structure. As a polymer which has a benzophenone structure in a side chain, the acryl-type polymer which has a benzophenone structure in a side chain is employable preferably.

(photoinitiator)

When using an ultraviolet-ray as an active energy ray for hardening an active energy ray-curable adhesive layer, it is preferable to contain a photoinitiator in the said adhesive layer from a viewpoint of reaction acceleration|stimulation or improvement of the utilization efficiency of light energy.

The photoinitiator includes, for example, a benzoin ether-based photoinitiator, an acetophenone-based photoinitiator, an α-hydroxyketone-based photoinitiator, an aromatic sulfonylchloride-based photoinitiator, a photoactive oxime-based photoinitiator, and a benzoin-based photoinitiator. Initiators, benzyl-based photoinitiators, benzophenone-based photoinitiators, ketal-based photoinitiators, thioxanthone-based photoinitiators, α-aminoketone-based photoinitiators, acylphosphine oxide-based photoinitiators, and the like may be mentioned. A photoinitiator can be used individually by 1 type or in combination of 2 or more type.

As a benzoin ether type photoinitiator, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2 -diphenylethan-1-one, anisolemethyl ether, etc. are mentioned. As the acetophenone-based photoinitiator, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenylketone, 4-phenoxydichloro Acetophenone, 4-t- butyl- dichloroacetophenone, etc. are mentioned. As the α-hydroxyketone-based photoinitiator, for example, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl] -2-hydroxy-2-methyl-1-propan-1-one and the like. As an aromatic sulfonyl chloride type|system|group photoinitiator, 2-naphthalenesulfonyl chloride etc. are mentioned, for example. Examples of the photoactive oxime-based photoinitiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. As a benzoin type photoinitiator, benzoin etc. are mentioned, for example. As a benzyl type photoinitiator, benzyl etc. are mentioned, for example. Examples of the benzophenone-based photoinitiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenylketone. As a ketal-type photoinitiator, benzyl dimethyl ketal etc. are mentioned, for example. Examples of the thioxanthone-based photoinitiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and 2,4- Dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, etc. are mentioned. Examples of the α-aminoketone-based photoinitiator include 2-methyl-1-[4-(methylthio)phenyl”-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino- 1-(4-morpholinophenyl)-butanone-1 etc. are mentioned. As an acylphosphine oxide type|system|group photoinitiator, 2,4,6- trimethylbenzoyl diphenyl phosphine oxide, bis(2,4,6- trimethylbenzoyl)-phenylphosphine oxide, etc. are mentioned, for example.

As said photoinitiator, you may use a commercial item. For example, "Omnirad 651", "Omnirad 184", "Omnirad 2959", "Omnirad 907", "Omnirad 369", "Omnirad 1173", "Omnirad TPO" manufactured by IGM Regins. ' and the like.

In some embodiments, as the photoinitiator, a photoinitiator that is difficult to decompose or generate radicals by heating may be used. For example, as the photoinitiator, a heat-resistant photoinitiator having a 10 wt% reduction temperature of 200°C or higher can be used. By using such a heat-resistant photoinitiator, even if it exposes to high temperature before a hardening process, the effect that the fall effect of the peeling force by hardening process with an active energy ray is hard to be impaired can be exhibited. In addition, the 10 wt% reduction temperature means that the photoinitiator is placed in a nitrogen atmosphere, and when the environmental temperature is raised from 23 °C to 300 °C at a temperature increase rate of 2 °C/min, the weight of the photoinitiator is 10 with respect to the weight before temperature increase It means the environmental temperature at the time when weight % decreased (that is, the weight of photoinitiator became 90 weight% with respect to the weight before temperature rise). The 10 wt% reduction temperature of the photoinitiator is more preferably 210°C or higher, still more preferably 220°C or higher. As a photoinitiator whose 10 weight% reduction|decrease temperature is such a range, For example, IGM Regins company make brand name "Omnirad 369", "Omnirad 127", "Omnirad 379", "Omnirad 819"; BASF Japan company make brand name "irgacure OXE02"; Lamberti company make brand names "Esacure one", "Esacure 1001m"; Asahi Electric Co., Ltd. brand names "Adeka Optomer N-1414", "Adeka Optomer N-1606", "Adeka Optomer N-1717", etc. are mentioned.

The adhesive layer containing a photoinitiator can be formed using the adhesive composition containing this photoinitiator. The method of making an adhesive composition contain a photoinitiator is not specifically limited. For example, it is preferable to add and mix a photoinitiator to the polymer (polymerization complete polymer) containing liquid typically in an adhesive composition. In this method, a photoinitiator may be added in the composition together with other additive components (eg, a crosslinking agent, etc.). As another method, a method of adding a polymerization initiator capable of functioning as a photoinitiator during polymerization of the polymer is exemplified. In this method, a polymerization initiator is added so that a predetermined amount may remain|survive after superposition|polymerization. The residual amount of the polymerization initiator (existence amount of the photoinitiator) can be adjusted by not only the addition amount of the polymerization initiator but also the polymer polymerization conditions, drying conditions at the time of forming the pressure-sensitive adhesive layer, curing conditions, and the like.

When an adhesive layer contains a photoinitiator, content of the photoinitiator in the adhesive layer is not specifically limited, It can set so that a desired effect may be exhibited suitably. In some embodiments, the content of the photoinitiator may be, for example, about 0.05 parts by weight or more, preferably about 0.1 parts by weight or more, and more preferably about 0.5 parts by weight or more with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer. desirable. By increase in content of a photoinitiator, the active energy ray sclerosis|hardenability of an adhesive layer improves. In some aspects, the content of the photoinitiator with respect to 100 parts by weight of the base polymer may be, for example, about 1.0 part by weight or more, about 2.0 parts by weight or more, or about 2.5 parts by weight or more. In addition, the content of the photoinitiator with respect to 100 parts by weight of the base polymer can be, for example, about 20 parts by weight or less, and usually it is suitable to be about 10 parts by weight or less, and it is about 8 parts by weight or less. Preferably, it is good also as about 6 weight part or less, and good also as about 4 weight part or less. It is preferable from a viewpoint of the storage stability (for example, the performance which suppresses the performance change by preserving the adhesive sheet before use) that there is not too much content of a photoinitiator.

<Formation of the pressure-sensitive adhesive layer>

The pressure-sensitive adhesive layer (eg, active energy ray-curable pressure-sensitive adhesive layer) of the pressure-sensitive adhesive sheet disclosed herein is formed from a pressure-sensitive adhesive composition including a base polymer (eg, an acrylic polymer) and, if necessary, other optional components. It may be an adhesive layer. The pressure-sensitive adhesive composition is a solvent-type pressure-sensitive adhesive composition containing a pressure-sensitive adhesive (adhesive component) in an organic solvent, an active energy ray-curable pressure-sensitive adhesive composition prepared so as to form a pressure-sensitive adhesive by curing with active energy rays such as ultraviolet rays or radiation, the pressure-sensitive adhesive It may be in various forms, such as a water-dispersible pressure-sensitive adhesive composition dispersed in water, a hot-melt pressure-sensitive adhesive composition that is coated in a heat-melted state to form a pressure-sensitive adhesive when cooled to near room temperature. In addition, the active energy ray-curable pressure-sensitive adhesive composition typically exhibits a degree of fluidity that can be applied at room temperature (generally 0° C. to 40° C., for example, about 25° C.), and is cured by irradiation with an active energy ray to the pressure-sensitive adhesive ( It is a liquid composition which forms a viscoelastic body).

The adhesive sheet which concerns on some aspect may be a structure which has the adhesive layer formed using a solvent-type adhesive composition or an active energy ray-curable adhesive composition. As an adhesive composition for forming an active energy ray-curable adhesive layer, a solvent-type adhesive composition is employable preferably from viewpoints, such as the easiness of control of active energy ray sclerosis|hardenability.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein can be formed by applying (eg, applying) the pressure-sensitive adhesive composition to an appropriate surface, and then appropriately performing curing treatment (drying, crosslinking, polymerization, etc.). When performing 2 or more types of hardening processes, these can be implemented simultaneously or over multiple steps. The adhesive layer of the multilayer structure of two or more layers can be produced by bonding together the previously formed adhesive layers. Or an adhesive composition may be apply|coated on the 1st adhesive layer formed previously, the adhesive composition may be hardened, and a 2nd adhesive layer may be formed.

Application|coating of an adhesive composition can be performed using conventional coaters, such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, and a spray coater, for example. In the pressure-sensitive adhesive sheet of the form having a support, as a method of forming the pressure-sensitive adhesive layer on the support, a direct method in which the pressure-sensitive adhesive composition is directly applied to the support to form the pressure-sensitive adhesive layer may be used, and the pressure-sensitive adhesive layer formed on the release surface is applied to the support body You may use the transcription method which transcribe|transfers to .

The adhesive sheet disclosed herein WHEREIN: The thickness of an adhesive layer is not specifically limited, According to the objective, it can select suitably. Usually, about 5-200 micrometers is suitable for the thickness of an adhesive layer, From a viewpoint of adhesiveness etc., Preferably it is about 10 micrometers or more (for example, 15 micrometers or more), 25 micrometers or more may be sufficient, and it is preferable It is preferably about 150 µm or less, more preferably 100 µm or less, still more preferably about 80 µm or less (for example, 60 µm or less, typically 40 µm or less), and may be 35 µm or less or less than 30 µm. When the adhesive sheet disclosed herein is a double-sided adhesive sheet provided with an adhesive layer on both surfaces of a base material, the thickness of each adhesive layer may be same or different.

<Additional adhesive layer>

Some aspects of the adhesive sheet disclosed herein WHEREIN: The structure in which the additional adhesive layer was laminated|stacked on the back side (opposite side to an adhesive surface) of the adhesive layer which comprises the adhesive surface may be sufficient as the adhesive sheet. The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface and the additional pressure-sensitive adhesive layer are preferably laminated in direct contact with each other. That is, it is preferable that a separator layer (for example, a resin film such as a polyester film) that completely blocks both pressure-sensitive adhesive layers is not interposed between the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface and the additional pressure-sensitive adhesive layer. The additional pressure-sensitive adhesive layer is, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive (natural rubber-based, synthetic rubber-based, a mixture thereof, etc.), a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, polyether-based pressure-sensitive adhesive, polyamide-based pressure-sensitive adhesive, It may be a pressure-sensitive adhesive layer comprising one or two or more types of pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as fluorine-based pressure-sensitive adhesives. From viewpoints of transparency, weather resistance, etc., in some aspects, an acrylic adhesive can be employ|adopted preferably as a constituent material of an additional adhesive layer. For other matters of the additional pressure-sensitive adhesive layer, the same structure as that of the above-described pressure-sensitive adhesive layer can be adopted, or an appropriate structure can be adopted according to the use or purpose based on publicly known or conventional techniques and common technical knowledge. , a detailed description is omitted here.

<mentioned>

In the adhesive sheet with a single-sided adhesive type or double-sided adhesive type base material, the base material for supporting (backing) the pressure-sensitive adhesive layer is, for example, a resin film, paper, cloth, rubber sheet, foam sheet, metal foil, or a composite thereof. Various sheet-like base materials, such as these, can be used. A single layer may be sufficient as the said base material, and the laminated body of the same type or different types of base materials may be sufficient as it. In addition, in this specification, a single|mono layer means the layer which consists of the same composition, and the thing of the form in which the layer which consists of the same composition was laminated|stacked is included.

In one preferred aspect, a base material having a resin sheet as a main component (resin film base material) can be used. Examples of the resin constituting the base material include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homo polypropylene, polybutene, poly Methylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer polyolefin resins such as coalescing; Polyurethane ; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonate; polyimide; polyether ether ketone; polyetherimide; polyamides such as aramid and wholly aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; Cellulose resin; silicone resin; and the like. The said resin can be used for formation of all or part (for example, any layer in the base material of a laminated structure of two or more layers) of a base material individually by 1 type or in combination of 2 or more types. When the adhesive layer which comprises an adhesive surface is an active energy ray-curable adhesive layer, it is preferable that a base material has active energy ray permeability|transmittance. Some aspects WHEREIN: The base material whose ultraviolet transmittance in wavelength 365nm is 40% - 100% (more preferably 60% - 100%) is employable preferably. When a substrate with high permeability is used, the pressure-sensitive adhesive layer can be easily cured.

Various additives such as fillers (inorganic fillers, organic fillers, etc.), antioxidants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, and colorants (pigments, dyes, etc.) may be blended with the substrate as needed.

The substrate can be produced by any suitable method. For example, it can manufacture by well-known methods, such as a calendering method, a casting method, an inflation extrusion method, and the T-die extrusion method. Moreover, you may manufacture by performing an extending|stretching process as needed.

On the surface of the pressure-sensitive adhesive layer side of the substrate, for the purpose of improving adhesion with the pressure-sensitive adhesive layer and the retention of the pressure-sensitive adhesive layer, for example, corona discharge treatment, plasma treatment, sand matting treatment, ozone exposure treatment, flame exposure treatment, high-pressure electric shock physical treatment such as exposure treatment and ionizing radiation treatment; chemical treatment such as acid treatment, alkali treatment, and chromic acid treatment; Easy adhesion treatment with a coating agent (base coat agent); A well-known or customary surface treatment of these etc. may be given. In addition, for the purpose of providing antistatic ability, etc., you may form the electroconductive vapor deposition layer containing a metal, an alloy, these oxides, etc. on the base material surface.

In some preferred embodiments, an undercoat layer is formed on the pressure-sensitive adhesive layer side surface of the substrate. In other words, an undercoat layer may be disposed between the substrate and the pressure-sensitive adhesive layer. The material for forming the undercoating layer is not particularly limited, and urethane (polyisocyanate)-based resin, polyester-based resin, acrylic resin, polyamide-based resin, melamine-based resin, olefin-based resin, polystyrene-based resin, epoxy-based resin, phenol One type, or two or more types, such as a system resin, an isocyanurate type resin, a polyvinyl acetate type resin, can be used. In the case where an acrylic pressure-sensitive adhesive layer is formed on a resin film substrate through an undercoating layer, a polyester-based, urethane-based, or acrylic undercoating layer is preferable. When the acrylic pressure-sensitive adhesive layer is formed on a polyester-based substrate such as a PET film with an undercoating layer interposed therebetween, the polyester-based undercoating layer is particularly preferable. The thickness of the undercoating layer is not particularly limited, and may generally be in the range of approximately 0.1 µm to 10 µm (eg, 0.1 µm to 3 µm, typically 0.1 µm to 1 µm). The undercoat layer may be formed using a known or customary coater such as a gravure roll coater or a reverse roll coater.

When the adhesive sheet disclosed herein is a single-sided adhesive adhesive sheet in which an adhesive layer is formed on one side of a base material, the adhesive layer non-formed side (back side) of the base material may be subjected to peeling treatment with a peeling agent (back side treating agent). . The back treatment agent that can be used in the formation of the back treatment layer is not particularly limited, and silicone-based back treatment agents, fluorine-based back treatment agents, long-chain alkyl-based back treatment agents, and other known or conventional treatment agents can be used depending on the purpose or use. .

The thickness of the substrate is not particularly limited and may be appropriately selected depending on the purpose, but may be generally about 3 µm to 800 µm. From the viewpoint of workability and handleability of the pressure-sensitive adhesive sheet (for example, workability at the time of sticking or peeling to an adherend), etc., the thickness of the substrate is suitably 5 µm or more, and preferably 10 µm or more, From a viewpoint of improving the protection property of the to-be-adhered body in wafer processing, it is preferable that it is 20 micrometers or more, 30 micrometers or more may be sufficient, and 40 micrometers or more may be sufficient. In some embodiments in which protection is more important, the thickness of the substrate may be, for example, 55 μm or more, 75 μm or more, or 90 μm or more. In addition, from the viewpoint of reducing the load on the adherend at the time of peeling from the adherend, the thickness of the substrate is usually preferably 300 µm or less, preferably 200 µm or less, and may be 150 µm or less. , 125 µm or less may be sufficient, 80 µm or less may be sufficient, and 60 µm or less may be sufficient.

The total thickness of the pressure-sensitive adhesive sheet disclosed herein (which may include an adhesive layer and a base material, but does not include a release liner) is not particularly limited, and is preferably in the range of approximately 10 µm to 1000 µm. It is preferable to set it as the range of about 15 micrometers - 300 micrometers in consideration of adhesiveness and handleability, and, as for the total thickness of an adhesive sheet, it is more preferable to set it as the range of about 20 micrometers - 200 micrometers. In addition, from the viewpoint of improving the protection properties of the adherend during wafer processing, the total thickness of the pressure-sensitive adhesive sheet is advantageously about 30 µm or more, preferably about 40 µm or more, and about 50 µm or more (for example, 60 µm). above) is more preferable. Some aspects in which protection is more important WHEREIN: The total thickness of an adhesive sheet may exceed 65 micrometers, may exceed 80 micrometers, and may exceed 100 micrometers.

<Use>

The pressure-sensitive adhesive sheet disclosed herein can be used for processing various wafers. For example, the adhesive sheet disclosed herein can be used for processing of various semiconductor wafers. The semiconductor wafer may be, for example, a compound semiconductor wafer such as a silicon wafer, a silicon carbide (SiC) wafer, a nitride semiconductor wafer (such as silicon nitride (SiN), gallium nitride (GaN), etc.), a gallium arsenide wafer, and the like. In the process of manufacturing a semiconductor element (for example, a semiconductor chip) from such a semiconductor wafer, the adhesive sheet disclosed herein is typically bonded to the said semiconductor wafer which was circuit-formed by the pre-process, It can be preferably used as an adhesive sheet for wafer processing for protecting and/or fixing the semiconductor wafer at the time of processing the said semiconductor wafer. Examples of the processing that can be applied to the semiconductor wafer after the pressure-sensitive adhesive sheet disclosed herein is pasted together until the pressure-sensitive adhesive sheet is peeled off includes, but is not limited to, back grind processing and dicing processing. In addition, the adhesive sheet disclosed herein can also be used for wafer processing of non-semiconductors such as glass and resin. In addition, in this specification, when the shape of the wafer (typically a semiconductor wafer) to be processed is changed by processing (for example, all or part thinning by back grind processing, piece by piece by dicing processing, etc.) Edo, the article after processing is continuously referred to as a wafer (typically a semiconductor wafer) in some cases.

The bonding to the wafer (typically a semiconductor wafer) of the adhesive sheet disclosed here can be performed by arbitrary appropriate methods. The temperature at the time of bonding an adhesive sheet together may be around room temperature (for example, 10 degreeC - 35 degreeC), and a temperature higher than the room temperature range (for example, more than 35 degreeC, Preferably 60 degreeC - 90 degreeC) may be sufficient as it. Bonding the pressure-sensitive adhesive sheet at a temperature higher than the room temperature region may be advantageous from the viewpoint of improving the adhesion of the pressure-sensitive adhesive sheet to the wafer. After bonding the pressure-sensitive adhesive sheets in the room temperature region, a temperature higher than the room temperature region (eg 40°C to 90°C, preferably 40°C to 60°C) and a pressure higher than atmospheric pressure (eg 1.5 to 10 atm, preferably 3 to 7 atm) may be subjected to a heat pressurization treatment. The time for performing the heat and pressurization treatment is not particularly limited, and can be set so that an appropriate treatment effect can be obtained. Some aspects WHEREIN: In consideration of the balance of the stability of a process effect, and productivity, the time for performing the said heat pressurization process can be made into 3 minutes - 1 hour (for example, 5 minutes - 30 minutes).

When the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet disclosed herein is an active energy ray-curable pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet is preferably bonded to an adherend, and then subjected to active energy ray irradiation and water peeling. can be used The irradiation conditions of an active energy ray are not specifically limited, It can set so that hardening of an active energy ray-curable adhesive layer can advance suitably. A person skilled in the art can set appropriate irradiation conditions without undue burden on the basis of common technical knowledge in the art, and therefore detailed description thereof will be omitted. As an example, when using an ultraviolet-ray as an active energy ray, the irradiation conditions of the ultraviolet-ray are the range of 50 mJ/cm<2> - 5000 mJ/cm<2>, and about 50 mJ/cm<2> - 2000 mJ/cm<2> of irradiation integrated light quantity, for example. or approximately 100 mJ/cm 2 to 2000 mJ/cm 2 , and the irradiation time may be approximately 1 second to 30 minutes.

<Semiconductor element manufacturing method>

One Embodiment of the semiconductor element manufacturing method using the said adhesive sheet for a wafer process is demonstrated below. The semiconductor element manufacturing method of this embodiment comprises the process (1) of bonding the adhesive surface of the adhesive sheet for a wafer process to the circuit formation surface side of the semiconductor wafer which has a circuit formation surface, To the said semiconductor wafer to which the said adhesive sheet was bonded, The process (2) which processes from the opposite side to the adhesive sheet, and the process (3) of peeling the said adhesive sheet from the semiconductor wafer after the said process are included.

Here, it is preferable to perform the said process (3) by supplying an aqueous|water-based peeling liquid to the peeling wire of the said adhesive sheet from the semiconductor wafer (to-be-adhered body) after a process. Thereby, an adhesive sheet can be made light-peelable, and the load given to a to-be-adhered body (semiconductor wafer after a process) at the time of peeling can be reduced. Therefore, the said adhesive sheet can be peeled efficiently, avoiding damage to a to-be-adhered body. In some aspects, the said process (3) can be performed suitably by the adhesive sheet peeling method mentioned later.

In addition, as the aqueous peeling solution in the technology disclosed by this specification (including the pressure-sensitive adhesive sheet for wafer processing, the pressure-sensitive adhesive composition, the semiconductor element manufacturing method, the pressure-sensitive adhesive sheet peeling method, etc.), water or a mixture containing water as a main component What made the solvent contain a small amount of additives as needed can be used. As a solvent other than water constituting the mixed solvent, a lower alcohol (eg, ethyl alcohol), a lower ketone (eg, acetone), etc. which can be uniformly mixed with water can be used. As said additive, well-known surfactant, a pH adjuster, etc. can be used. From the viewpoint of avoiding contamination of the adherend, in some embodiments, an aqueous peeling solution substantially free of additives can be preferably used. From the viewpoint of environmental hygiene, it is particularly preferable to use water as the aqueous stripper. The water is not particularly limited, and can be used, for example, distilled water, ion-exchanged water, tap water, etc. in consideration of the purity and availability that can be obtained depending on the use.

When the adhesive layer which comprises the said adhesive surface is an active energy ray-curable adhesive layer, before peeling an adhesive sheet, the process which irradiates an active energy ray and hardens the said active energy ray-curable adhesive layer is performed. Typically, the peeling force of an adhesive sheet is reduced by the said hardening process. By peeling the adhesive sheet with water after such hardening process, the load given to a to-be-adhered body (semiconductor wafer after a process) at the time of peeling can be reduced more effectively. From a viewpoint of making the adhesion reliability with respect to the to-be-adhered body in a process (2) compatible with the light-peelability in a process (3), it is preferable to perform the said hardening process after a process (2).

In some embodiments, the process (2) may be a back grind process. In this case, the adhesive sheet for wafer processing is used as a back grind tape. The back grind process may be performed by any suitable method. The back grinding process may be a process of thinning the semiconductor wafer to which the adhesive sheet was pasted until the thickness of the semiconductor wafer becomes 150 micrometers or less, 100 micrometers or less, 50 micrometers or less, or 30 micrometers or less, for example. In such an aspect to be thinned, the effect by applying the technique disclosed herein can be preferably exhibited. In addition, the back grinding process may be implemented so that the inside of an annular convex part may become a recessed part (that is, so that a TAIKO (trademark) wafer may be obtained). In this case, the thickness of the thinned semiconductor wafer means the thickness of the said recessed part. Moreover, although it does not specifically limit, The thickness of the semiconductor wafer before back grinding may be about 500 micrometers - 1000 micrometers, for example.

The semiconductor device manufacturing method disclosed herein may further include any suitable process. Examples of such optional processes include, but are not limited to, an etching process, a photolithography process, an ion implantation process, a dicing process, a die bonding process, a wire bonding process, a packaging process, and the like. Each of the steps illustrated above may be performed in the step (2), after the step (2), before the step (3), or after the step (3).

<Adhesive sheet peeling method>

According to this specification, the adhesive sheet peeling method of peeling the adhesive sheet affixed to a to-be-adhered body from the to-be-adhered body is provided. In the method, in the peeling wire of the pressure-sensitive adhesive sheet from the adherend, in a state where an aqueous peeling solution exists at the interface between the adherend and the pressure-sensitive adhesive sheet, it follows the movement of the peeling wire to release the aqueous peeling solution. It may include a water peeling process of peeling the pressure-sensitive adhesive sheet from the adherend while proceeding to enter the interface. Here, the peeling front refers to a point at which the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet starts to come off from the adherend when peeling the pressure-sensitive adhesive sheet from the adherend is carried out. According to the said water peeling process, an adhesive sheet can be peeled from a to-be-adhered body using the said aqueous|water-based peeling liquid effectively. The peeling method can be preferably carried out, for example, in an embodiment in which any pressure-sensitive adhesive sheet disclosed herein is peeled from the adherend.

The adherend in the peeling method disclosed herein may be various semiconductor wafers exemplified above. The semiconductor wafer may be a circuit-formed semiconductor wafer. The peeling method disclosed here can be used suitably as a method of peeling from the said circuit formation surface the adhesive sheet affixed to the circuit formation surface of the semiconductor wafer with a circuit formation.

The adhesive sheet peeled from a to-be-adhered body by the said peeling method contains the adhesive layer which comprises an adhesive surface, and the said adhesive layer is comprised by the adhesive. As the pressure-sensitive adhesive sheet, any pressure-sensitive adhesive sheet disclosed herein can be preferably used. Therefore, the said peeling method is preferable as a peeling method of any adhesive sheet disclosed herein.

In some embodiments, the peeling method comprises: forming an initial peeling wire by forcibly lifting the adhesive sheet from the adherend at one end of the outer edge of the adhesive sheet affixed to the adherend; supplying an aqueous peeling solution to the electric wire, and peeling the adhesive sheet from the adherend while advancing the entry of the aqueous peeling solution into the interface between the adhesive sheet and the adherend following the movement of the peeling wire It can be preferably implemented in an aspect. Formation of the peeling wire in the initial stage is performed, for example, by inserting the tip of a jig such as a cutter knife or needle into the interface between the pressure-sensitive adhesive sheet and the adherend, scraping the pressure-sensitive adhesive sheet with a claw or claw, and lifting the pressure-sensitive adhesive sheet. It can be carried out in such a way that the tip of the adhesive sheet is lifted by attaching a strongly adhesive adhesive tape, sucker, or the like to the back surface of the plate. In this way, after forming an initial peeling wire, supplying an aqueous stripping liquid to the peeling wire and starting water peeling can supply the aqueous stripping liquid to the said peeling wire efficiently. In addition, in this peeling method and the pressure-sensitive adhesive sheet used in the peeling method, good water releasability after an operation of forcibly forming an initial peeling wire is performed to create a starting point of peeling, and when such an operation is not performed The high water-resistance reliability in this is preferably compatible.

In some embodiments, in the peeling method, after supplying an aqueous stripping solution to the initial peeling wire (that is, supplying an aqueous stripping solution at the start of water peeling), supplying a new aqueous stripping solution It can carry out preferably from the aspect which advances peeling of an adhesive sheet without doing it. Alternatively, if the aqueous peeling solution that follows the movement of the peeling wire and enters the interface between the pressure-sensitive adhesive sheet and the adherend in the middle of water peeling is likely to be depleted or insufficient, intermittently or continuously after the start of the water peeling. may be supplied additionally. For example, when the length of the peeling wire increases with the progress of peeling (for example, when water peeling is advanced in the radial direction of the circle from one end of the outer edge of the disk-shaped adherend), or In the case where the aqueous stripping solution tends to remain on the surface, an aspect in which the aqueous stripping solution is additionally supplied after the start of the water peeling can be preferably adopted. In addition, one location may be sufficient as the position which supplies an aqueous|water-based peeling liquid, and multiple locations may be sufficient as it. When the aqueous stripping solution is additionally supplied after the start of the water peeling, the number of positions to which the aqueous stripping solution is supplied after the start of the water peeling may be increased or decreased.

Example

Hereinafter, some examples related to the present invention will be described, but it is not intended to limit the present invention to those shown in these examples. In addition, in the following description, "part" and "%" are based on weight unless otherwise indicated.

<Measurement of stick slip degree>

1. Measurement of unirradiated normal peeling stick slip degree SSd0

A test piece is prepared by cutting the non-UV-irradiated adhesive sheet to be measured into a strip shape with a width of 10 mm. In an environment of 23° C. and 50% RH, the adhesive surface of the test piece is bonded to the mirror surface of a 6-inch silicon wafer (manufactured by Shin-Etsu Chemical Co., Ltd., 6-inch N<100>-100) as an adherend with a hand roller, to prepare a sample for evaluation by allowing it to stand for 30 minutes.

Thereafter, in an environment of 23° C. and 50% RH, a cutter knife is inserted into the interface between the test piece and the adherend of the sample for evaluation, and one end in the longitudinal direction of the test piece is peeled from the adherend, according to JIS Z0237: 2009 「10. 4. 1 Method 1: 180° Peel Adhesion to Test Plate”, specifically, at a test temperature of 23° C., using a tensile tester (device name “tensile compression tester, VPA-3” manufactured by Kyowa Interfacial Science Co., Ltd.), peeling rate Data of peel force is acquired for every 0.25 mm of peeling distance, peeling until a peeling distance becomes 100 mm on the conditions of 300 mm/min and 180 degree|times of peeling angles. Among the obtained peeling forces, the stick-slip degree of an adhesive sheet is computed using the data of the peeling force in 30-70 mm of peeling distances. All measurements of the stick-slip degree are performed three times, and the average value thereof is defined as the unirradiated normal peeling stick-slip degree SSd0 [10 ^-3 N/10 mm]. The measurement of the stick-slip degree is performed so that peeling of the test piece affixed to a to-be-adhered body may advance from bottom to top.

2. Measurement of unirradiated water peeling stick slip degree SSw0

In the sample for evaluation of non-UV irradiation, 20 µl of distilled water is supplied to the point at which the test piece starts to fall from the adherend (peel interface) during peeling of the test piece from the adherend, and the stick after supplying the distilled water Measure the slip. All measurements of the stick-slip degree are performed three times, and the average value thereof is set as the unirradiated water peeling stick-slip degree SSw0 [10 ^-3 N/10 mm].

3. Measurement of normal peel stick slip degree SSd1 after irradiation

The unirradiated normal peeling stick slip of the non-irradiated evaluation sample prepared in the same manner as in the measurement of SSd0 was placed on the substrate side of the pressure-sensitive adhesive sheet (measured on the adhesive side of the adhesive surface under the following conditions in an environment of 23°C and 50%RH). From the opposite side (hereinafter also referred to as “rear side”), using a UV irradiator manufactured by Nitto Seiki Co., Ltd., trade name “NEL SYSTEM UM810” (high pressure mercury lamp light source), illuminance of 60 mW/cm 2 and integrated light quantity of 500 mJ/cm 2 Irradiating UV light as a condition.

Thereafter, in an environment of 23° C. and 50% RH, a cutter knife is inserted into the interface between the test piece for evaluation after UV irradiation and the adherend, and one end in the longitudinal direction of the test piece is peeled from the adherend, and the micro Irradiation Normal peeling stick-slip degree It carries out similarly to the measurement of SSd0, and measures a stick-slip degree. The measurement is performed three times, and the average value thereof is usually taken as the peeling stick-slip degree SSd1 [10 ^-3 N/10 mm] after irradiation.

4. Measurement of water peeling stick slip degree SSw1 after irradiation

The normal peeling stick slip after irradiation is also carried out similarly to the measurement of SSd1, and the sample for evaluation after UV irradiation is produced. In the sample for evaluation after UV irradiation, 20 μl of distilled water is supplied to the point at which the test piece starts to fall from the adherend (peel interface) while the test piece is peeled from the adherend, and the distilled water is supplied and the stick slip measure the degree All measurements of the stick-slip degree are performed three times, and the average value thereof is set as the water peeling stick-slip degree SSw1 [10 ^-3 N/10 mm] after irradiation.

<Measurement of Peeling Force>

1. Measurement of unirradiated normal peel force Fd0

A test piece is prepared by cutting the non-UV-irradiated adhesive sheet to be measured into a strip shape with a width of 10 mm. In an environment of 23° C. and 50% RH, the adhesive surface of the test piece is bonded to the mirror surface of a 6-inch silicon wafer (manufactured by Shin-Etsu Chemical Co., Ltd., 6-inch N<100>-100) as an adherend with a hand roller, to prepare a sample for evaluation by allowing it to stand for 30 minutes.

Thereafter, in an environment of 23° C. and 50% RH, a cutter knife is inserted into the interface between the test piece and the adherend of the sample for evaluation, and one end in the longitudinal direction of the test piece is peeled from the adherend, according to JIS Z0237: 2009 「10. 4. 1 Method 1: 180° Peel Adhesion to Test Plate”, specifically, at a test temperature of 23° C., using a tensile tester (device name “DT9503-1000N” manufactured by TOMS), peeling rate 300 mm/min, peeling The peel force is measured under the condition of an angle of 180 degrees. A measurement is performed three times, and let the average value be unirradiated normal peeling force Fd0 [N/10mm]. The measurement of peeling force is performed so that peeling of the test piece affixed to a to-be-adhered body may advance from bottom to top.

2. Measurement of peel force Fw0 of unirradiated water

In the sample for evaluation without UV irradiation, 20 µl of distilled water is supplied to the point at which the test piece starts to fall from the adherend (peel interface) during peeling of the test piece from the adherend, and peeling after supplying the distilled water measure the force. The measurement of the peeling force is all performed three times, and let their average value be the unirradiated water peeling force Fw0 [N/10mm].

3. Measurement of normal peel force Fd1 after irradiation

To the sample for evaluation of non-UV irradiation prepared in the same manner as in the measurement of the unirradiated normal peel force Fd0, the substrate side of the pressure-sensitive adhesive sheet (opposite side of the measurement pressure-sensitive adhesive surface. Hereinafter, “ from the back side"), using a UV irradiator manufactured by Nitto Seiki Co., Ltd., trade name "NEL SYSTEM UM810" (high pressure mercury lamp light source), irradiating ultraviolet rays under the conditions of illuminance of 60 mW/cm2 and accumulated light quantity of 500 mJ/cm2 .

Thereafter, in an environment of 23° C. and 50% RH, a cutter knife is inserted into the interface between the test piece for evaluation after UV irradiation and the adherend, and one end in the longitudinal direction of the test piece is peeled from the adherend, and the micro Irradiation Normal It carries out similarly to the measurement of peeling force Fd0, and measures a peeling force. The measurement is performed three times, and the average value thereof is taken as normal peeling force Fd1 [N/10 mm] after irradiation.

4. Measurement of water peel force Fw1 after irradiation

After the irradiation, a sample for evaluation after UV irradiation is prepared in the same manner as in the measurement of the normal peel force Fd1. In the sample for evaluation after UV irradiation, 20 µl of distilled water is supplied to the point where the test piece starts to fall from the adherend (peel interface) during peeling of the test piece from the adherend, and the peeling force after supplying the distilled water measure The measurement is performed three times, and the average value thereof is taken as the water peeling force Fw1 [N/10 mm] after irradiation.

<Example 1>

(Preparation of adhesive composition)

In a reaction vessel equipped with a Liebig condenser, a nitrogen introduction tube, a thermometer and a stirring device, 100 parts of 2-ethylhexylacrylate (2EHA) as a monomer raw material, 25.5 parts of acryloylmorpholine (ACMO) and 2-hydroxylethylacryl A solution of polymer P1a was obtained by pouring 18.5 parts of the rate (HEA), toluene as a polymerization solvent, and 0.3 parts of benzoyl peroxide (BPO) as a polymerization initiator to carry out solution polymerization in a nitrogen atmosphere. The weight average molecular weight (Mw) of the polymer P1a was 900,000. The glass transition temperature (Tg) of the polymer P1a based on the composition of the monomer raw material is -42.7°C.

After cooling the solution of the polymer P1a to room temperature, 12.3 parts of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Co., Ltd., trade name "Karenz MOI") is added, and further dibutyltin (IV) dilau A solution of polymer P1 having a carbon-carbon double bond was obtained by adding 0.1 parts of a rate (manufactured by Wako Pure Chemical Industries, Ltd.) and stirring the mixture at 50°C for 24 hours in an air atmosphere to react the polymer P1a with MOI.

To the solution of the polymer P1, per 100 parts of the polymer P1 in the solution, the isocyanate-based crosslinking agent A1 (trimethylolpropane/tolylene diisocyanate trimer adduct, manufactured by Tosoh Corporation, trade name “Colonate L”, solid content concentration of 75 wt% ) was added 5 parts based on solid content, and also 1 part of photoinitiators (the IGM Regins company make, brand name "Omnirad 369") was added and mixed by adding 1 part, and the adhesive composition C1 was prepared.

(Production of adhesive sheet)

A pressure-sensitive adhesive composition C1 was applied to the release surface of a release film R1 (Mitsubishi Resin Co., Ltd., MRF38) having a thickness of 38 µm, in which one side of the polyethylene terephthalate (PET) film is a release surface by silicone treatment, and 2 at 140 ° C. It dried for minutes and formed the 20-micrometer-thick adhesive layer. After bonding the said adhesive layer to the easily bonding surface of the easily bonding process PET film (50 micrometers in thickness) as a base material, aging for 2 days was performed at 50 degreeC, and the adhesive sheet which concerns on this example was obtained.

<Example 2>

To the solution of the above-mentioned polymer P1, per 100 parts of the polymer P1 in the solution, a surfactant (polyoxyethylene sorbitan monolaurate, sorbitan fatty acid ester manufactured by Kao Corporation, trade name "Leodol TW-L 120", ethylene oxide Additional moles 20, HLB 16.7) 0.5 parts were further added. Except for the above-mentioned point, it carried out similarly to preparation of the adhesive composition C1, and prepared the adhesive composition C2. Except having used this adhesive composition C2, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

In addition, the surfactant, in the form of an ethyl acetate solution, was used so that the above amount was added based on the solid content. Similarly to the pressure-sensitive adhesive compositions C4 and C7, the following amount of surfactant was added to the polymer solution in the form of an ethyl acetate solution on a solid basis.

<Example 3>

(Preparation of adhesive composition)

100 parts of n-butyl acrylate (BA), 78 parts of ethyl acrylate (EA) and 2-hydroxylethyl acrylate (HEA) as monomer raw materials in a reaction vessel equipped with a Liebig condenser, a nitrogen inlet tube, a thermometer and a stirring device ) 40 parts and toluene as a polymerization solvent, 0.3 parts of benzoyl peroxide (BPO) as a polymerization initiator, and solution polymerization were performed under nitrogen atmosphere to obtain a solution of polymer P3a. The weight average molecular weight (Mw) of the polymer P3a was 500,000. The glass transition temperature (Tg) of the polymer P3a based on the composition of the monomer raw material is -37.2°C.

After cooling the solution of the polymer P3a to room temperature, 43.6 parts of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Co., Ltd., trade name "Karenz MOI") is added, and further, dibutyltin (IV) dilau A solution of polymer P3 having a carbon-carbon double bond was obtained by adding 0.2 parts of a rate (manufactured by Wako Pure Chemical Industries, Ltd.) and stirring the mixture at 50°C for 24 hours in an air atmosphere for an addition reaction of MOI to the polymer P3a.

To the solution of the polymer P3, per 100 parts of the polymer P3 in the solution, the isocyanate-based crosslinking agent A1 (trimethylolpropane/tolylene diisocyanate trimer adduct, manufactured by Tosoh Corporation, trade name “Colonate L”, solid content concentration of 75 wt% ) was added 5 parts on a solid content basis, and 1 part of photoinitiators (the IGM Regins company make, brand name "Omnirad 369") was further added and mixed by adding 1 part, and the adhesive composition C3 was prepared. Except having used this adhesive composition C3, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

<Example 4>

To the solution of the above polymer P3, per 100 parts of the polymer P3 in the solution, a surfactant (polyoxyethylene sorbitan monolaurate, sorbitan fatty acid ester manufactured by Kao Corporation, trade name "Leodol TW-L 120", ethylene oxide Added mole number 20, HLB 16.7) 0.5 part was further added. Except for the above-mentioned point, it carried out similarly to preparation of the adhesive composition C3, and prepared the adhesive composition C4. Except having used this adhesive composition C4, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

<Example 5>

To the solution of the polymer P3, per 100 parts of the polymer P3 in the solution, the isocyanate-based crosslinking agent A1 (trimethylolpropane/tolylene diisocyanate trimer adduct, manufactured by Tosoh Corporation, trade name “Colonate L”, solid content concentration of 75 wt% ) was added on the basis of the solid content, and 1 part of a photoinitiator (manufactured by IGM Regins, trade name "Omnirad 369") was further added and mixed to prepare an adhesive composition C5. Except having used this adhesive composition C5, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

<Example 6>

(Preparation of adhesive composition)

In a reaction vessel equipped with a Liebig condenser, a nitrogen introduction tube, a thermometer and a stirring device, 75 parts of 2-ethylhexylacrylate (2EHA) as a monomer raw material, 25 parts of acryloylmorpholine (ACMO), 3 parts of acrylic acid (AA) and 0.1 parts of 2-hydroxylethyl acrylate (HEA), ethyl acetate as a polymerization solvent, and 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and solution polymerization in a nitrogen atmosphere By carrying out, the solution of polymer P6 was obtained. The weight average molecular weight (Mw) of polymer P6 was 1.2 million. The glass transition temperature (Tg) of the polymer P6 based on the composition of the monomer raw material is -37.4°C.

To the solution of the polymer P6, per 100 parts of the polymer P6 in the solution, the isocyanate-based crosslinking agent A1 (trimethylolpropane/tolylene diisocyanate trimer adduct, manufactured by Tosoh Corporation, trade name “Colonate L”, solid content concentration of 75 wt% ) on a solid content basis and 0.7 parts of an epoxy-based crosslinking agent A2 (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") on a solid content basis by adding and mixing 0.7 parts, thereby preparing an adhesive composition C6. Except having used this adhesive composition C6, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

<Example 7>

0.5 part of surfactant (polyoxyethylene sorbitan monolaurate, sorbitan fatty acid ester manufactured by Kao Corporation, trade name "Leodol TW-L 120", ethylene oxide added mole number 20, HLB 16.7) is added to the solution of the polymer P6 was added with Except for the above-mentioned point, it carried out similarly to preparation of the adhesive composition C6, and prepared the adhesive composition C7. Except having used this adhesive composition C7, it carried out similarly to preparation of the adhesive sheet which concerns on Example 1, and obtained the adhesive sheet which concerns on this example.

<Performance evaluation>

For the pressure-sensitive adhesive sheets according to each example, unirradiated normal peeling stick slip degree SSd0, unirradiated water peeling stick slip degree SSw0, post irradiation normal peeling stick slip degree SSd1 and post irradiation water peeling stick slip degree SSw1 were measured. Moreover, about the adhesive sheet which concerns on each example, unirradiated normal peeling force Fd0, unirradiated water peeling force Fw0, after irradiation normal peeling force Fd1, and irradiated water peeling force Fw1 were measured. A result is shown in Table 1.

As shown in Table 1, all the adhesive sheets of Examples 1-5 were able to reduce the stick-slip degree by performing UV irradiation. In addition, all of the adhesive sheets of Examples 1-7 were able to reduce the stick-slip degree by performing water peeling. In particular, as for the adhesive sheets of Examples 1-5 and 7, the fall of the remarkable stick-slip degree was confirmed by performing at least any of water peeling and UV irradiation. Moreover, the fall of the especially remarkable stick-slip degree was confirmed by performing water peeling, after the adhesive sheet of Examples 1-5 performed UV irradiation.

In addition, all of the adhesive sheets of Examples 1-5 were able to reduce peeling force significantly by performing UV irradiation. In addition, all of the adhesive sheets of Examples 1-7 were able to reduce peeling force by performing water peeling. Especially, the fall of the especially remarkable peeling force was confirmed by performing water peeling after all the adhesive sheets of Examples 1-5 performed UV irradiation.

As mentioned above, although the specific example of this invention was demonstrated in detail, these are only an illustration and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples exemplified above.

1, 2, 3, 4, 5, 6; Adhesive sheet for wafer processing
10 ; materials
10A; side 1
10B; 2nd side
21, 22; adhesive layer
21A; first adhesive side
21B; 2nd adhesive side
31, 32; release liner
x ; peel distance
y ; peel force
SS ; stick slip diagram
L ; standard length

Claims (7)

A pressure-sensitive adhesive sheet for wafer processing comprising a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface,
Using a sample for evaluation produced by affixing the adhesive surface of the pressure-sensitive adhesive sheet to a silicon wafer as an adherend, at least any of the following methods A, B, and C, at a peeling rate of 300 mm/min. The measured stick-slip degree [10 ^-3 N/10 mm] is 30 or less.
Method A: An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the sample for evaluation, and then the stick-slip degree at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.
Method B: The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and then the stick-slip degree when the pressure-sensitive adhesive sheet is peeled off from the adherend is measured.
Method C: After irradiating the sample for evaluation with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and supplying an aqueous peeling solution to the interface between the pressure-sensitive adhesive sheet and the adherend, the pressure-sensitive adhesive sheet The stick-slip degree at the time of peeling from the said to-be-adhered body is measured. The method of claim 1,
The adhesive sheet whose peeling force measured by at least any method of the following method E, method F, and method G using the said sample for evaluation is 0.10 N/10 mm or less.
Method E: An aqueous peeling solution is supplied to the interface between the pressure-sensitive adhesive sheet and the adherend in the sample for evaluation, and then the peeling force at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.
Method F: The sample for evaluation is irradiated with an active energy ray from the side opposite to the adherend of the pressure-sensitive adhesive sheet, and then the peeling force at the time of peeling the pressure-sensitive adhesive sheet from the adherend is measured.
Method G: After irradiating the sample for evaluation with an active energy ray from the side opposite to the adherend of the adhesive sheet, and supplying an aqueous peeling solution to the interface between the adhesive sheet and the adherend, the adhesive sheet was removed The peeling force at the time of peeling from the said to-be-adhered body is measured. 3. The method according to claim 1 or 2,
The adhesive sheet whose peeling force at the time of peeling the said adhesive sheet from the said to-be-adhered body using the said sample for evaluation without irradiating an active energy ray to the sample for evaluation is 0.20 N/10 mm or more. 4. The method according to any one of claims 1 to 3,
The pressure-sensitive adhesive layer is an active energy ray-curable pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet. 5. The method according to any one of claims 1 to 4,
^{The stick-slip degree [10 -3} N/10 mm] measured by at least one of the method B and the method C under the condition of a peeling rate of 300 mm/min using the evaluation sample is 10 or less. Sheet. 6. The method according to any one of claims 1 to 5,
^{The adhesive sheet whose stick-slip degree [10 -3} N/10 mm] measured by the said method C on the conditions of 300 mm/min of peeling rate using the said sample for evaluation is less than 3. 7. The method according to any one of claims 2 to 6,
The adhesive sheet whose peeling force measured by the at least one method of the said method F and the said method G using the said sample for evaluation is less than 0.050 N/10mm.

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