JPWO2018181766A1 - Method for manufacturing semiconductor device and double-sided pressure-sensitive adhesive sheet - Google Patents

Abstract

A method for producing a semiconductor device using a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer, a substrate containing expandable particles, a non-tacky substrate, and a second pressure-sensitive adhesive layer in this order, A method for manufacturing a semiconductor device, comprising steps (1) to (4), and a double-sided pressure-sensitive adhesive sheet used in the method. Step (1): a step of attaching a hard support to the adhesive surface of the second adhesive layer Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the first adhesive layer (3) ): The semiconductor chip and the peripheral portion of the semiconductor chip on the adhesive surface of the first adhesive layer are covered with a sealing material, and the sealing material is cured to cure and seal the semiconductor chip. Step (4) of obtaining a cured sealing body sealed with a material: a step of expanding the expandable particles and peeling the double-sided pressure-sensitive adhesive sheet from the cured sealing body. In this case, it is possible to suppress the occurrence of misalignment of the semiconductor chip in the manufacturing process of the package, and it is excellent in productivity, and excellent in the flatness of the rewiring layer forming surface of the obtained semiconductor device.

Description

  The present invention relates to a method for manufacturing a semiconductor device and a double-sided pressure-sensitive adhesive sheet.

In recent years, electronic devices have been reduced in size, weight, and functionality, and accordingly, semiconductor devices mounted on electronic devices have also been required to be smaller, thinner, and denser.
A semiconductor chip may be mounted on a package close to its size in some cases. Such a package is sometimes called a CSP (Chip Scale Package). Examples of the CSP include a WLP (Wafer Level Package) that is completed by processing to a package final step in a wafer size, and a PLP (Panel Level Package) that is processed and completed by a panel size larger than the wafer size to a package final step. .

  WLP and PLP are classified into a fan-in type and a fan-out type. In a fan-out type WLP (hereinafter, also referred to as “FOWLP”) and a PLP (hereinafter, also referred to as “FOLP”), a semiconductor chip is covered with a sealing material so as to have an area larger than the chip size. Is formed, and the rewiring layer and the external electrodes are formed not only on the circuit surface of the semiconductor chip but also on the surface region of the sealing material.

By the way, FOWLP and FOPLP are, for example, a mounting step of mounting a plurality of semiconductor chips on a temporary fixing adhesive sheet (hereinafter also referred to as a “temporary fixing sheet”), and a sealing material provided with fluidity. Covering step, a curing step of thermally curing the sealing material, a peeling step of peeling the temporary fixing sheet from the sealing body, and forming a rewiring layer on the exposed surface of the semiconductor chip side. It is manufactured through a rewiring layer forming step.
In the temporary fixing sheet used in the above step, no misalignment of the semiconductor chip occurs between the coating step and the curing step (hereinafter, also referred to as “sealing step”), and the semiconductor chip Adhesiveness to the extent that the sealing material does not enter the adhesive interface between the sheet and the temporary fixing sheet is required. After the sealing step, releasability that can be easily removed without adhesive residue is required. That is, the temporary fixing sheet used in the production of FOWLP and FOPLP is required to have both the adhesive property at the time of use and the peelability after use.

  For example, Patent Document 1 discloses a method for manufacturing FOWLP, in which a sealing step is performed on a temporary fixing sheet having a substrate made of a polyimide film and an adhesive layer made of a silicone-based adhesive provided on the surface of the substrate. And then peeling off the temporary fixing sheet while bending it by hand. However, the step of peeling the temporary fixing sheet by hand or the like is complicated, and from the viewpoint of improving productivity, it is required that the temporary fixing sheet can be peeled with a smaller external force.

  As a temporary fixing sheet having excellent releasability, for example, Patent Literature 2 discloses that a heat-expandable adhesive layer containing heat-expandable microspheres is provided on at least one surface of a base material, and is temporarily fixed when cutting electronic components. A heat-peelable pressure-sensitive adhesive sheet is disclosed. In the production of FOWLP and FOPLP, it is conceivable to use the heat-peelable pressure-sensitive adhesive sheet described in Patent Document 2.

JP 2015-32646 A Japanese Patent No. 3594853

However, according to the study of the present inventors, when the heat-peelable pressure-sensitive adhesive sheet described in Patent Document 2 is used as a temporary fixing sheet in the production of FOWLP and FOPLP, the elastic modulus of the heat-expandable pressure-sensitive adhesive layer is low. It has been found that, during the placing step and the sealing step, the placed semiconductor chip sinks into the adhesive sheet side or the semiconductor chip is displaced. As a result, a step is formed between the surface of the semiconductor chip and the surface of the encapsulant on the surface of the semiconductor chip after removing the adhesive sheet after the sealing step (hereinafter, also referred to as the “rewiring layer forming surface”). As a result, the flatness is inferior and the positional accuracy of the semiconductor chip is reduced. Such a decrease in flatness of the surface on which the rewiring layer is formed and a decrease in the positional accuracy of the semiconductor chip lead to a decrease in the rewiring accuracy.
Also, when removing the pressure-sensitive adhesive sheet, even if it is heated to expand the heat-expandable pressure-sensitive adhesive layer, the semiconductor chip has sinked into the pressure-sensitive adhesive sheet side, so it can be peeled off without a certain amount of external force. Can be difficult.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can suppress the occurrence of misalignment of a semiconductor chip in a process of manufacturing a fan-out type package. An object of the present invention is to provide a method for manufacturing a semiconductor device having excellent flatness of a formation surface, and a double-sided pressure-sensitive adhesive sheet used in the method.

The present inventors have solved the above-mentioned problems by using a double-sided pressure-sensitive adhesive sheet having a specific layer configuration including a base material that is non-tacky, including expandable particles, in a manufacturing process of a fan-out type package. I found that I got it.
That is, the present invention relates to the following [1] to [10].
[1] A method for manufacturing a semiconductor device using a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer, a non-adhesive base material containing expandable particles, and a second pressure-sensitive adhesive layer in this order. hand,
A method for manufacturing a semiconductor device, comprising the following steps (1) to (4).
Step (1): a step of attaching a hard support to the adhesive surface of the second adhesive layer Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the first adhesive layer Step (3) ): The semiconductor chip and the peripheral portion of the semiconductor chip on the adhesive surface of the first adhesive layer are covered with a sealing material, and the sealing material is cured to cure and seal the semiconductor chip. Step of obtaining a cured sealing body sealed with a material Step (4): a step of expanding the expandable particles and peeling the double-sided pressure-sensitive adhesive sheet from the cured sealing body [2] Further, the following steps ( 5) The method for manufacturing a semiconductor device according to the above [1], which includes 5).
Step (5): Step of forming a rewiring layer on the cured sealing body from which the double-sided pressure-sensitive adhesive sheet has been peeled off [3] The expandable particles are heat-expandable particles; The production of the semiconductor device according to the above [1] or [2], wherein the step of heating the pressure-sensitive adhesive sheet expands the thermally expandable particles and peels the double-sided pressure-sensitive adhesive sheet from the cured sealing body. Method.
[4] The method for manufacturing a semiconductor device according to the above [3], wherein the expansion start temperature (t) of the thermally expandable particles is 120 to 250 ° C.
[5] The method for manufacturing a semiconductor device according to the above [4], wherein the base material satisfies the following requirements (1) and (2).
-Requirement (1): The storage elastic modulus E '(100) of the base material at 100 ° C is 2.0 × 10 ⁵ Pa or more.
-Requirement (2): The storage elastic modulus E '(t) of the base material at the expansion start temperature (t) of the thermally expandable particles is 1.0 × 10 ⁷ Pa or less.
[6] The pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the expandable particles have an average particle size before expansion at 23 ° C. of 3 to 100 μm.
[7] The method according to [1] to [6], wherein the storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer at 23 ° C. is 1.0 × 10 ^{4 to} 1.0 × 10 ⁸ Pa. A method for manufacturing a semiconductor device according to any one of the above.
[8] The above-mentioned [1] to [7], wherein the ratio of the thickness of the base material to the thickness of the first pressure-sensitive adhesive layer (base material / first pressure-sensitive adhesive layer) at 23 ° C. is 0.2 or more. The method for manufacturing a semiconductor device according to any one of the above.
[9] The material according to any one of [1] to [8] above, wherein the thickness of the substrate at 23 ° C. is 10 to 1000 μm, and the thickness of the first pressure-sensitive adhesive layer is 1 to 60 μm. A method for manufacturing a semiconductor device.
[10] The method for manufacturing a semiconductor device according to any one of [1] to [9], wherein a probe tack value on a surface of the base material is less than 50 mN / 5 mmφ.
[11] A double-sided pressure-sensitive adhesive sheet used in the method for manufacturing a semiconductor device according to any one of [1] to [10], which includes a first pressure-sensitive adhesive layer and expandable particles, and is non-tacky. A double-sided pressure-sensitive adhesive sheet having a base material and a second pressure-sensitive adhesive layer in this order.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the semiconductor device which can suppress generation | occurrence | production of the displacement of a semiconductor chip in the manufacturing process of a fan-out type package, is excellent in productivity, and is excellent in the flatness of the rewiring layer formation surface of the obtained semiconductor device , And a double-sided pressure-sensitive adhesive sheet used in the production method can be provided.

It is a sectional view of a double-sided pressure sensitive adhesive sheet showing an example of composition of a double-sided pressure sensitive adhesive sheet concerning this embodiment. FIG. 4 is a cross-sectional view illustrating an example of the manufacturing method according to the embodiment. FIG. 3 is a sectional view illustrating an example of the manufacturing method according to the embodiment, following FIG. 2; FIG. 4 is a sectional view illustrating an example of the manufacturing method according to the embodiment, following FIG. 3;

In the present invention, the “active ingredient” refers to a component excluding a diluting solvent among components contained in a target composition.
The mass average molecular weight (Mw) is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and specifically, a value measured based on the method described in Examples.

In the present invention, for example, “(meth) acrylic acid” indicates both “acrylic acid” and “methacrylic acid”, and the same applies to other similar terms.
Further, regarding a preferable numerical range (for example, a range of content and the like), the lower limit and the upper limit described stepwise can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", "preferable lower limit (10)" and "more preferable upper limit (60)" are combined to obtain "10 to 60". You can also.

[Method of Manufacturing Semiconductor Device]
The method for manufacturing a semiconductor device according to the present embodiment uses a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer, a non-tacky base material containing expandable particles, and a second pressure-sensitive adhesive layer in this order. A method for manufacturing a semiconductor device by using the following method (1) to (4).
Step (1): a step of attaching a hard support to the adhesive surface of the second adhesive layer Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the first adhesive layer Step (3) ): The semiconductor chip and the peripheral portion of the semiconductor chip on the adhesive surface of the first adhesive layer are covered with a sealing material, and the sealing material is cured to cure and seal the semiconductor chip. Step of obtaining a cured sealing body sealed with a material Step (4): a step of expanding the expandable particles to peel off the double-sided pressure-sensitive adhesive sheet from the cured sealing body A double-sided pressure-sensitive adhesive sheet used in the method for manufacturing a semiconductor device will be described, and then each manufacturing step including steps (1) to (4) will be described.

<Double-sided adhesive sheet>
The double-sided pressure-sensitive adhesive sheet according to the present embodiment includes a first pressure-sensitive adhesive layer, a non-tacky base material containing expandable particles (hereinafter, also referred to as “expandable base material”), and a second pressure-sensitive adhesive layer. , In this order, is not particularly limited.
The shape of the double-sided pressure-sensitive adhesive sheet can take any shape such as a sheet shape, a tape shape, and a label shape.

(Configuration of double-sided adhesive sheet)
FIG. 1A is a cross-sectional view of the double-sided pressure-sensitive adhesive sheet 10 according to the present embodiment.
As shown in FIG. 1A, the double-sided pressure-sensitive adhesive sheet 10 according to the present embodiment has a configuration in which a base material 11 is sandwiched between a first pressure-sensitive adhesive layer 121 and a second pressure-sensitive adhesive layer 122.
The double-sided pressure-sensitive adhesive sheet according to the present embodiment further includes a release material 131 on the pressure-sensitive adhesive surface 121a of the first pressure-sensitive adhesive layer 121 like the double-sided pressure-sensitive adhesive sheet 10a illustrated in FIG. A release material 132 may be further provided on the adhesive surface 122a of the agent layer 122.
In the double-sided pressure-sensitive adhesive sheet 10a shown in FIG. 1B, the peeling force of the release material 131 from the first pressure-sensitive adhesive layer 121 and the peeling force of the release material 132 from the second pressure-sensitive adhesive layer 122 are substantially the same. In such a case, when the two release materials are pulled outward to separate them, a phenomenon occurs in which the first pressure-sensitive adhesive layer 121 and the second pressure-sensitive adhesive layer 122 are separated and peeled with the two release materials. There is. From the viewpoint of suppressing such a phenomenon, it is preferable that the two release materials 131 and 132 use two types of release materials designed so that the release forces from the adhesive layers adhered to each other are different. The release materials 131 and 132 are appropriately removed when the double-sided pressure-sensitive adhesive sheet 10a is used in the method for manufacturing a semiconductor device according to the present embodiment.
Another double-sided pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet 10a shown in FIG. It may be a double-sided pressure-sensitive adhesive sheet having a configuration in which a laminate of materials is wound in a roll shape.
Here, the double-sided pressure-sensitive adhesive sheet according to the present embodiment has a configuration in which another layer is provided between the expandable base material and the first pressure-sensitive adhesive layer, and between the expandable base material and the second pressure-sensitive adhesive layer. There may be.
However, from the viewpoint of a double-sided pressure-sensitive adhesive sheet that can be easily peeled off with a small force, the base material 11, the first pressure-sensitive adhesive layer 121, and the base material, as shown in the double-sided pressure-sensitive adhesive sheet shown in FIGS. 11 and the second pressure-sensitive adhesive layer 122 preferably have a configuration in which they are directly laminated.

  Hereinafter, the expandable base material, the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the release material used as necessary, which are included in the double-sided pressure-sensitive adhesive sheet according to the present embodiment, will be described in order.

(Expandable substrate)
An intumescent substrate is a substrate that contains intumescent particles and is non-tacky.
In general, a heat-expandable pressure-sensitive adhesive layer such as the pressure-sensitive adhesive sheet described in Patent Document 2 contains a pressure-sensitive adhesive having a low elastic modulus as a main component and a sufficient amount of expandable particles. Thickness is required. As a result, a misalignment of the semiconductor chip occurs between the mounting step and the sealing step of the semiconductor chip, and the semiconductor chip sinks into the adhesive sheet side, thereby causing a problem that the surface on which the rewiring layer is formed cannot be flattened. obtain.
On the other hand, in the double-sided pressure-sensitive adhesive sheet according to the present embodiment, since the expandable particles are contained in the non-adhesive resin having a high elastic modulus, the thickness of the first pressure-sensitive adhesive layer on which the semiconductor chip is mounted is adjusted, the adhesive strength, The degree of freedom in design, such as control of the viscoelastic modulus, is improved. As a result, the occurrence of displacement of the semiconductor chip can be suppressed, and the semiconductor chip can be prevented from sinking into the double-sided pressure-sensitive adhesive sheet, so that the rewiring layer forming surface having excellent flatness can be formed.
Furthermore, when the double-sided pressure-sensitive adhesive sheet according to the present embodiment is used, since the semiconductor chip is placed on the pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer, the expandable base material and the surface on which the rewiring layer is formed may be in direct contact. Absent. Thereby, the residue derived from the expandable particles and a part of the greatly deformed pressure-sensitive adhesive layer adhere to the surface on which the rewiring layer is formed, or the uneven shape formed on the heat-expandable pressure-sensitive adhesive layer is transferred to the surface on which the rewiring layer is formed. As a result, a decrease in smoothness is suppressed, and a rewiring layer forming surface excellent in cleanliness and smoothness is obtained.

The thickness of the expandable base material is preferably 10 to 1000 μm, more preferably 20 to 500 μm, further preferably 25 to 400 μm, and still more preferably 30 to 300 μm.
In the present specification, the thickness of the expandable base material means a value measured by the method described in Examples.

The expandable base material of the pressure-sensitive adhesive sheet is a non-sticky base material.
In the present invention, the determination as to whether the substrate is a non-adhesive substrate is performed when the probe tack value measured according to JIS Z0237: 1991 with respect to the surface of the target substrate is less than 50 mN / 5 mmφ. The substrate is determined to be a “non-tacky substrate”.
Here, the probe tack value on the surface of the expandable base material used in the present embodiment is usually less than 50 mN / 5 mmφ, preferably less than 30 mN / 5 mmφ, more preferably less than 10 mN / 5 mmφ, and still more preferably 5 mN / mmφ. It is less than 5 mmφ.
In the present specification, a specific method of measuring the probe tack value on the surface of the expandable base material is based on the method described in Examples.

The intumescent base material of the pressure-sensitive adhesive sheet of the present embodiment contains a resin and expandable particles. .
Further, the expandable base material can be formed from a resin composition (y) containing a resin and expandable particles.
Hereinafter, each component contained in the resin composition (y) which is a material for forming the expandable base material will be described.

<Resin>
The resin contained in the resin composition (y) is not particularly limited as long as the expandable base material is non-adhesive, and may be a non-adhesive resin or an adhesive resin. .
That is, even if the resin contained in the resin composition (y) is an adhesive resin, the adhesive resin undergoes a polymerization reaction with the polymerizable compound in the process of forming the expandable base material from the resin composition (y). It suffices if the obtained resin becomes a non-adhesive resin and the expandable base material containing the resin becomes non-adhesive.

The weight average molecular weight (Mw) of the resin contained in the resin composition (y) is preferably 1,000 to 1,000,000, more preferably 1,000 to 700,000, and still more preferably 1,000 to 500,000.
When the resin is a copolymer having two or more types of structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer. It may be.

  The content of the resin is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and still more preferably 65 to 90% by mass relative to the total amount (100% by mass) of the active ingredient of the resin composition (y). %, More preferably 70 to 85% by mass.

The resin contained in the resin composition (y) preferably contains at least one selected from an acrylic urethane-based resin and an olefin-based resin.
The following resin (U1) is preferable as the acrylic urethane-based resin.
-An acrylic urethane resin (U1) obtained by polymerizing a urethane prepolymer (UP) and a vinyl compound containing a (meth) acrylate.

[Acrylic urethane resin (U1)]
Examples of the urethane prepolymer (UP) serving as the main chain of the acrylic urethane-based resin (U1) include a reaction product of a polyol and a polyvalent isocyanate.
The urethane prepolymer (UP) is preferably obtained by further performing a chain extension reaction using a chain extender.

Examples of the polyol serving as a raw material of the urethane prepolymer (UP) include an alkylene type polyol, an ether type polyol, an ester type polyol, an ester amide type polyol, an ester ether type polyol, and a carbonate type polyol.
These polyols may be used alone or in combination of two or more.
The polyol used in the present embodiment is preferably a diol, more preferably an ester diol, an alkylene diol and a carbonate diol, and further preferably an ester diol and a carbonate diol.

Examples of the ester diol include alkane diols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol; ethylene glycol, propylene glycol, One or more selected from diols such as alkylene glycols such as diethylene glycol and dipropylene glycol; and phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, and diphenylmethane-4. , 4'-dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, heptic acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, hexa Hydrophthalic acid, Condensed polymers of dicarboxylic acids such as hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid, and one or more selected from anhydrides thereof are exemplified.
Specifically, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene hexamethylene adipate diol, Polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol and polyneo And pentyl terephthalate diol.

  Examples of the alkylene type diol include alkane diols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol; ethylene glycol, propylene glycol, Alkylene glycols such as diethylene glycol and dipropylene glycol; polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol; polyoxyalkylene glycols such as polytetramethylene glycol;

  Examples of the carbonate type diol include 1,4-tetramethylene carbonate diol, 1,5-pentamethylene carbonate diol, 1,6-hexamethylene carbonate diol, 1,2-propylene carbonate diol, and 1,3-propylene carbonate diol. , 2,2-dimethylpropylene carbonate diol, 1,7-heptamethylene carbonate diol, 1,8-octamethylene carbonate diol, 1,4-cyclohexane carbonate diol, and the like.

Examples of the polyvalent isocyanate used as a raw material of the urethane prepolymer (UP) include an aromatic polyisocyanate, an aliphatic polyisocyanate, and an alicyclic polyisocyanate.
These polyvalent isocyanates may be used alone or in combination of two or more.
These polyvalent isocyanates may be a modified trimethylolpropane adduct, a modified buret reacted with water, or a modified isocyanurate containing an isocyanurate ring.

  Among these, as the polyvalent isocyanate used in the present embodiment, diisocyanate is preferable, and 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), and 2,6-triisocyanate One or more selected from range isocyanate (2,6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate are more preferable.

  Examples of the alicyclic diisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, and 1,4-cyclohexane. Examples thereof include diisocyanate, methyl-2,4-cyclohexane diisocyanate, and methyl-2,6-cyclohexane diisocyanate, and isophorone diisocyanate (IPDI) is preferable.

In the present embodiment, the urethane prepolymer (UP) serving as the main chain of the acrylic urethane resin (U1) is a reaction product of a diol and a diisocyanate, and is a linear urethane prepolymer having an ethylenically unsaturated group at both terminals. Polymers are preferred.
As a method for introducing an ethylenically unsaturated group into both terminals of the linear urethane prepolymer, a NCO group at a terminal of the linear urethane prepolymer obtained by reacting a diol with a diisocyanate compound, and a hydroxyalkyl (meth) acrylate And a method of reacting

  Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy. Butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like.

The vinyl compound serving as a side chain of the acrylic urethane resin (U1) contains at least a (meth) acrylate.
As the (meth) acrylic acid ester, one or more selected from alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate are preferable, and it is more preferable to use the alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate together.

  When the alkyl (meth) acrylate and the hydroxyalkyl (meth) acrylate are used in combination, the mixing ratio of the hydroxyalkyl (meth) acrylate to 100 parts by mass of the alkyl (meth) acrylate is preferably 0.1 to 100 parts by mass, Preferably it is 0.5 to 30 parts by mass, more preferably 1.0 to 20 parts by mass, even more preferably 1.5 to 10 parts by mass.

  The carbon number of the alkyl group of the alkyl (meth) acrylate is preferably 1 to 24, more preferably 1 to 12, further preferably 1 to 8, and still more preferably 1 to 3.

  Examples of the hydroxyalkyl (meth) acrylate include the same hydroxyalkyl (meth) acrylate used for introducing an ethylenically unsaturated group into both ends of the above-mentioned linear urethane prepolymer.

Examples of vinyl compounds other than (meth) acrylic acid esters include, for example, aromatic hydrocarbon-based vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl acetate and vinyl propionate , (Meth) acrylonitrile, N-vinylpyrrolidone, polar group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, and meth (acrylamide).
These may be used alone or in combination of two or more.

  The content of the (meth) acrylic acid ester in the vinyl compound is preferably 40 to 100% by mass, more preferably 65 to 100% by mass, and still more preferably the total amount (100% by mass) of the vinyl compound. It is 80 to 100% by mass, more preferably 90 to 100% by mass.

  The total content of the alkyl (meth) acrylate and the hydroxyalkyl (meth) acrylate in the vinyl compound is preferably from 40 to 100% by mass, more preferably from 65 to 100% by mass, based on the total amount (100% by mass) of the vinyl compound. It is 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass.

The acrylic urethane resin (U1) used in the present embodiment is obtained by mixing a urethane prepolymer (UP) and a vinyl compound containing a (meth) acrylate and polymerizing both.
In the polymerization, it is preferable to further add a radical initiator.

  In the acrylic urethane resin (U1) used in the present embodiment, the content ratio of the structural unit (u11) derived from the urethane prepolymer (UP) to the structural unit (u12) derived from the vinyl compound [(u11) / (U12)] is preferably 10/90 to 80/20, more preferably 20/80 to 70/30, further preferably 30/70 to 60/40, and still more preferably 35/65 by mass ratio. ５５55/45.

(Olefin resin)
The olefin-based resin suitable as the resin contained in the resin composition (y) is a polymer having at least a structural unit derived from an olefin monomer.
The olefin monomer is preferably an α-olefin having 2 to 8 carbon atoms, and specific examples include ethylene, propylene, butylene, isobutylene, 1-hexene and the like.
Among these, ethylene and propylene are preferred.

Specific olefinic resins, for example, ultra low density polyethylene (VLDPE, density: 880 kg / ^{m 3} or more 910 kg / ^m less than ^3), low density polyethylene (LDPE, density: 910 kg / ^{m 3} or more 915 kg / ^m less than ³ ), medium density polyethylene (MDPE, density: 915 kg / ^{m 3} or more 942kg / ^m less than ^3), high density polyethylene (HDPE, density: 942kg / ^{m 3} or higher), polyethylene resins such as linear low density polyethylene; polypropylene resin (PP); polybutene resin (PB); ethylene-propylene copolymer; olefin-based elastomer (TPO); poly (4-methyl-1-pentene) (PMP); ethylene-vinyl acetate copolymer (EVA); -Vinyl alcohol copolymer (EVOH); ethylene-propylene Olefin-based terpolymers such as-(5-ethylidene-2-norbornene);

  In the present embodiment, the olefin-based resin may be a modified olefin-based resin further subjected to at least one modification selected from acid modification, hydroxyl group modification, and acrylic modification.

For example, as the acid-modified olefin resin obtained by subjecting the olefin resin to acid modification, a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or an anhydride thereof to the above-mentioned unmodified olefin resin. Is mentioned.
Examples of the unsaturated carboxylic acids or anhydrides thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth) acrylic acid, maleic anhydride, and itaconic anhydride , Glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride and the like.
The unsaturated carboxylic acids or anhydrides may be used alone or in combination of two or more.

The acrylic-modified olefin-based resin obtained by subjecting the olefin-based resin to an acrylic modification includes a modification obtained by graft-polymerizing an alkyl (meth) acrylate as a side chain to the unmodified olefin-based resin as a main chain. Polymers.
The alkyl group of the alkyl (meth) acrylate preferably has 1 to 20, more preferably 1 to 16, and still more preferably 1 to 12 carbon atoms.
Examples of the above-mentioned alkyl (meth) acrylate include the same compounds as the compounds that can be selected as the monomer (a1 ′) described below.

Examples of the hydroxyl group-modified olefin resin obtained by subjecting the olefin resin to hydroxyl group modification include a modified polymer obtained by graft-polymerizing a hydroxyl group-containing compound to the above-mentioned unmodified olefin resin as a main chain.
Examples of the hydroxyl-containing compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl. Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylate and 4-hydroxybutyl (meth) acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

(Resin other than acrylic urethane resin and olefin resin)
In the present embodiment, the resin composition (y) may contain a resin other than the acrylic urethane-based resin and the olefin-based resin as long as the effects of the present invention are not impaired.
Examples of such a resin include vinyl resins such as polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; and acrylonitrile-butadiene-styrene copolymer. Polycarbonate; Polyether ether ketone; Polyether sulfone; Polyphenylene sulfide; Polyimide resin such as polyetherimide and polyimide; Polyamide resin; Acrylic resin; Fluorinated resins and the like can be mentioned.
The content ratio of the resin other than the acrylic urethane-based resin and the olefin-based resin is preferably less than 30 parts by mass, more preferably 20 parts by mass, based on 100 parts by mass of the total amount of the resin contained in the resin composition (y). Less than 10 parts by weight, more preferably less than 5 parts by weight, even more preferably less than 1 part by weight.

<Expandable particles>
The expandable particles are not particularly limited as long as they can form irregularities in the first pressure-sensitive adhesive layer by expanding themselves by an external stimulus, and can reduce the adhesive force with the adherend.
Examples of the expandable particles include, for example, thermally expandable particles that expand by heating, energy-ray expandable particles that expand by irradiation with energy rays, and the like, and from the viewpoint of versatility and handleability, are heat-expandable particles. Is preferred.

The thermally expandable particles are preferably particles whose expansion start temperature (t) is adjusted to 120 to 250 ° C.
In this specification, the expansion start temperature (t) of the thermally expandable particles means a value measured based on the following method.
[Measurement method of expansion start temperature (t) of thermally expandable particles]
To an aluminum cup having a diameter of 6.0 mm (5.65 mm inner diameter) and a depth of 4.8 mm, 0.5 mg of the thermally expandable particles to be measured are added, and an aluminum lid (5.6 mm in diameter, 0.3 mm in thickness) is placed on the aluminum cup. 1 mm) is prepared.
Using a dynamic viscoelasticity measuring device, the height of the sample is measured from the upper part of the aluminum lid while a force of 0.01 N is applied to the sample by a pressurizer. Then, with the force of 0.01 N applied by the pressurizer, the heater is heated from 20 ° C. to 300 ° C. at a rate of 10 ° C./min, and the displacement of the pressurizer in the vertical direction is measured. Let the displacement start temperature be the expansion start temperature (t).

As the heat-expandable particles, a microencapsulated foaming agent comprising an outer shell made of a thermoplastic resin, and an inner component encapsulated in the outer shell and vaporized when heated to a predetermined temperature. Preferably, there is.
Examples of the thermoplastic resin constituting the outer shell of the microencapsulated foaming agent include a vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

Examples of the components included in the outer shell include propane, butane, pentane, hexane, heptane, octane, nonane, decane, isobutane, isopentane, isohexane, isoheptane, isooctane, isononane, isodecane, cyclopropane, cyclobutane, and cyclopentane. , Cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isododecane, cyclotridecane, hexylcyclohexane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nanodecane, isotridecane, 4-methyldodecane, isotetradecane, isopentadecane, iso Hexadecane, 2,2,4,4,6,8,8-heptamethylnonane, isoheptadecane, isooctadecane, isonanodecane, , 6,10,14-tetramethylpentadecane, cyclotridecane, heptylcyclohexane, n-octylcyclohexane, cyclopentadecane, nonylcyclohexane, decylcyclohexane, pentadecylcyclohexane, hexadecylcyclohexane, heptadecylcyclohexane, octadecylcyclohexane and the like. .
These inclusion components may be used alone or in combination of two or more.
The expansion start temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of the inclusion component.

  The volume maximum expansion rate of the thermally expandable particles used in the present embodiment when heated to a temperature equal to or higher than the thermal expansion start temperature (t) is preferably 1.5 to 100 times, more preferably 2 to 80 times, and still more preferably. Is 2.5 to 60 times, more preferably 3 to 40 times.

The average particle diameter of the expandable particles before expansion at 23 ° C. used in the present embodiment is preferably 3 to 100 μm, more preferably 4 to 70 μm, further preferably 6 to 60 μm, and still more preferably 10 to 50 μm. .
The average particle diameter of the expandable particles before expansion is a volume median particle diameter (D ₅₀ ), which is measured by a laser diffraction type particle size distribution analyzer (for example, product name “Master Sizer 3000” manufactured by Malvern). In the particle distribution of the expandable particles before expansion measured as used herein, it means a particle diameter corresponding to 50% of the cumulative volume frequency calculated from the smaller particle diameter of the expandable particles before expansion.

The 90% particle diameter (D ₉₀ ) of the expandable particles before expansion at 23 ° C. used in the present embodiment is preferably 10 to 150 μm, more preferably 20 to 100 μm, still more preferably 25 to ₉₀ μm, and still more preferably. Is 30 to 80 μm.
The 90% particle diameter (D ₉₀ ) of the expandable particles before expansion is measured using a laser diffraction type particle size distribution analyzer (for example, product name “Master Sizer 3000” manufactured by Malvern). Means the particle size corresponding to 90% of the cumulative volume frequency calculated from the smaller particle size of the expandable particles before expansion in the particle distribution of the expandable particles.

  The content of the expandable particles is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, and still more preferably 10 to 10% by mass based on the total amount (100% by mass) of the active ingredient of the resin composition (y). It is 30% by mass, more preferably 15 to 25% by mass.

<Additive for base material>
The resin composition (y) used in the present embodiment may contain a base material additive contained in a base material of a general pressure-sensitive adhesive sheet as long as the effect of the present invention is not impaired.
Examples of such an additive for a substrate include an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, and a coloring agent.
These additives for base materials may be used alone or in combination of two or more.
When these base material additives are contained, the content of each base material additive is preferably 0.0001 to 20 parts by mass with respect to 100 parts by mass of the resin in the resin composition (y). And more preferably 0.001 to 10 parts by mass.

<Solvent-free resin composition (y1)>
As one mode of the resin composition (y) used in the present embodiment, an oligomer having an ethylenically unsaturated group having a mass average molecular weight (Mw) of 50,000 or less, an energy ray polymerizable monomer, and the above-described expandable particles are blended. And a solvent-free resin composition (y1) containing no solvent.
In the solventless resin composition (y1), a solvent is not blended, but the energy ray-polymerizable monomer contributes to the improvement of the plasticity of the oligomer.
By irradiating the coating film formed from the solvent-free resin composition (y1) with an energy ray, an expandable base material can be obtained.

  The type, shape, and blending amount (content) of the expandable particles blended in the solventless resin composition (y1) are as described above.

  The mass average molecular weight (Mw) of the oligomer contained in the solvent-free resin composition (y1) is 50,000 or less, preferably 1,000 to 50,000, more preferably 2,000 to 40,000, still more preferably 3,000 to 35,000, More preferably, it is 4000 to 30,000.

The oligomer may be any of the resins contained in the resin composition (y) described above, as long as the resin has an ethylenically unsaturated group having a mass average molecular weight (Mw) of 50,000 or less. Polymers (UP) are preferred.
In addition, as the oligomer, a modified olefin resin having an ethylenically unsaturated group or the like may be used.

  The total content of the oligomer and the energy ray-polymerizable monomer in the solvent-free resin composition (y1) is preferably 50 to the total amount (100% by mass) of the solvent-free resin composition (y1). To 99% by mass, more preferably 60 to 95% by mass, still more preferably 65 to 90% by mass, and still more preferably 70 to 85% by mass.

Examples of the energy beam polymerizable monomer include isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, and adamantane ( Alicyclic polymerizable compounds such as meth) acrylate and tricyclodecane acrylate; aromatic polymerizable compounds such as phenylhydroxypropyl acrylate, benzyl acrylate and phenol-ethylene oxide-modified acrylate; tetrahydrofurfuryl (meth) acrylate, morpholine acrylate, N- Heterocyclic polymerizable compounds such as vinylpyrrolidone and N-vinylcaprolactam.
These energy ray polymerizable monomers may be used alone or in combination of two or more.

  In the solvent-free resin composition (y1), the content ratio of the oligomer and the energy ray-polymerizable monomer (the oligomer / the energy ray-polymerizable monomer) is preferably 20/80 to 90 / by mass ratio. 10, more preferably 30/70 to 85/15, even more preferably 35/65 to 80/20.

In the present embodiment, it is preferable that the solventless resin composition (y1) further contains a photopolymerization initiator.
By containing the photopolymerization initiator, the curing reaction can be sufficiently advanced even by irradiation with relatively low energy energy rays.

Examples of the photopolymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, and azobisisobutyrol Examples include nitrile, dibenzyl, diacetyl, 8-chloranthraquinone and the like.
These photopolymerization initiators may be used alone or in combination of two or more.

  The amount of the photopolymerization initiator is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 4 parts by mass, based on the total amount (100 parts by mass) of the oligomer and the energy ray-polymerizable monomer. Preferably it is 0.02 to 3 parts by mass.

<Storage modulus of substrate>
The storage elastic modulus E ′ (23) at 23 ° C. of the expandable base material of the pressure-sensitive adhesive sheet of this embodiment is preferably 1.0 × 10 ⁶ Pa or more, more preferably 5.0 × 10 ^{6 to} 5.0. × 10 ¹² Pa, more preferably 1.0 × 10 ^{7 to} 1.0 × 10 ¹² Pa, still more preferably 5.0 × 10 ^{7 to} 1.0 × 10 ¹¹ Pa, and still more preferably 1.0 × 10 ¹¹ Pa. a ^{10 8} ~1.0 × 10 10 Pa. By using an expandable base material having a storage elastic modulus E ′ (23) within the above range, it is possible to prevent the semiconductor chip from being displaced and prevent the semiconductor chip from sinking into the first pressure-sensitive adhesive layer. You can also.
For example, the semiconductor chip is placed so that its circuit surface is covered with the adhesive surface of the adhesive layer. A known device such as a flip chip bonder or a die bonder may be used for mounting the semiconductor chip. When the semiconductor chip is placed on the adhesive layer of the adhesive sheet by using the flip chip bonder or the die bonder in the above procedure, a force for pushing the semiconductor chip in the thickness direction of the adhesive sheet is applied. There is a possibility that the agent layer will sink excessively in the thickness direction of the agent layer. In addition, when a semiconductor chip is placed on an adhesive sheet using a flip chip bonder or a die bonder, a force for moving the semiconductor chip in the horizontal direction of the adhesive sheet is also applied, so that the semiconductor chip is positioned in the horizontal direction of the adhesive layer. There is a risk of displacement. However, these problems can also be solved by using an expandable base material that satisfies the storage elastic modulus E ′ (23).
In the present specification, the storage elastic modulus E ′ of the expansible base material at a predetermined temperature means a value measured by the method described in Examples.

Furthermore, it is preferable that the expandable base material of the pressure-sensitive adhesive sheet of the present embodiment has a storage elastic modulus satisfying the following requirement (1).
-Requirement (1): The storage elastic modulus E '(100) of the expandable base material at 100 ° C is 2.0 × 10 ⁵ Pa or more.
By having the expandable base material satisfying the requirement (1), the flow of the expandable particles can be moderately suppressed even in the temperature environment of the sealing step in the manufacturing process of FOWLP and FOPLP. The adhesive surface of the first adhesive layer is less likely to be deformed. As a result, the position of the semiconductor chip can be prevented from being shifted, and the semiconductor chip can be prevented from sinking into the first pressure-sensitive adhesive layer.

In view of the above, the storage elastic modulus E ′ (100) of the expandable base material is more preferably 4.0 × 10 ⁵ Pa or more, further preferably 6.0 × 10 ⁵ Pa or more, and still more preferably 8.0. × 10 ⁵ Pa or more, more preferably 1.0 × 10 ⁶ Pa or more.
Further, in the sealing step, from the viewpoint of effectively suppressing the displacement of the semiconductor chip, the storage elastic modulus E ′ (100) of the expandable base material is preferably 1.0 × 10 ¹² Pa or less, more preferably. The pressure is 1.0 × 10 ¹¹ Pa or less, more preferably 1.0 × 10 ¹⁰ Pa or less, and still more preferably 1.0 × 10 ⁹ Pa or less.

When the expandable base material of the pressure-sensitive adhesive sheet of the present embodiment contains thermally expandable particles as expandable particles, the storage elastic modulus preferably satisfies the following requirement (2).
Requirement (2): The storage elastic modulus E ′ (t) of the expandable base material at the expansion start temperature (t) of the thermally expandable particles is 1.0 × 10 ⁷ Pa or less.
By having the expandable base material satisfying the requirement (2), the expandable base material easily deforms following the volume expansion of the thermally expandable particles at the temperature at which the thermally expandable particles expand, and the first pressure-sensitive adhesive It becomes easy to form irregularities on the adhesive surface of the layer. Thereby, it can be separated from the object by a small external force.

From the above viewpoint, the storage elastic modulus E ′ (t) of the expandable base material is more preferably 9.0 × 10 ⁶ Pa or less, further preferably 8.0 × 10 ⁶ Pa or less, and still more preferably 6.0. × 10 ⁶ Pa or less, more preferably 4.0 × 10 ⁶ Pa or less.
In addition, from the viewpoint of suppressing the flow of the expanded thermally expandable particles, improving the shape retention of the unevenness formed on the adhesive surface of the first adhesive layer, and further improving the releasability, the storage of the expandable base material is improved. The elastic modulus E ′ (t) is preferably 1.0 × 10 ³ Pa or more, more preferably 1.0 × 10 ⁴ Pa or more, and still more preferably 1.0 × 10 ⁵ Pa or more.

(First adhesive layer)
The first pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet of the present embodiment may be any as long as it contains a pressure-sensitive resin. It may contain additives.
The first pressure-sensitive adhesive layer is preferably a non-expandable pressure-sensitive adhesive layer from the viewpoint of preventing the mounted semiconductor chip from sinking into the first pressure-sensitive adhesive layer due to heating in the sealing step.

In the pressure-sensitive adhesive sheet of this embodiment, the pressure-sensitive adhesive force of the pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer at 23 ° C. before the expandable particles expand is preferably 0.1 to 10.0 N / 25 mm, more preferably 0.1 to 10.0 N / 25 mm. It is 2 to 8.0 N / 25 mm, further preferably 0.4 to 6.0 N / 25 mm, and still more preferably 0.5 to 4.0 N / 25 mm.
When the adhesive force is 0.1 N / 25 mm or more, the semiconductor chip can be sufficiently fixed to such an extent that the positional displacement of the semiconductor chip in the sealing step can be prevented.
On the other hand, if the adhesive strength is 10.0 N / 25 mm or less, when peeling from the adherend, it can be easily peeled off with a slight external force.
In addition, the said adhesive force means the value measured by the method described in the Example.

In the pressure-sensitive adhesive sheet of the present embodiment, the storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer at 23 ° C. is preferably 1.0 × 10 ^{4 to} 1.0 × 10 ⁸ Pa, more preferably. ^{5.0 × 10 4 ~5.0 × 10 7} Pa, more preferably ^{1.0 × 10 5 ~1.0 × 10 7} Pa.
In the case of a pressure-sensitive adhesive sheet having a plurality of pressure-sensitive adhesive layers, the pressure-sensitive adhesive layer to which the semiconductor chip is attached preferably has a storage shear modulus G ′ (23) within the above range, and the semiconductor chip has a greater thickness than the expandable base material. It is preferable that the storage shear modulus G ′ (23) of all the pressure-sensitive adhesive layers on the side where is adhered be within the above range.
When the storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer is 1.0 × 10 ⁴ Pa or more, it is possible to prevent the semiconductor chip from being displaced and to prevent the semiconductor chip from being displaced. Can be prevented from sinking.
On the other hand, when the storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer is 1.0 × 10 ⁸ Pa or less, the surface of the first pressure-sensitive adhesive layer is expanded due to expansion of the expandable particles in the expandable base material. Irregularities are easily formed on the surface, and as a result, it can be easily peeled off with a small force.
In the present specification, the storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer means a value measured by the method described in Examples.

  The thickness of the first pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment is based on the viewpoint of developing excellent adhesive strength, and on the surface of the first pressure-sensitive adhesive layer due to the expansion of the expandable particles in the expandable base material. From the viewpoint of easily forming irregularities, the thickness is preferably 1 to 60 μm, more preferably 2 to 50 μm, further preferably 3 to 40 μm, and still more preferably 5 to 30 μm.

In the pressure-sensitive adhesive sheet of the present embodiment, the ratio of the thickness of the expandable base material to the thickness of the first pressure-sensitive adhesive layer at 23 ° C. (expandable base material / first pressure-sensitive adhesive layer) is defined as a rewiring layer forming surface. Is preferably 0.2 or more, more preferably 0.5 or more, further preferably 1.0 or more, and still more preferably 5.0 or more, from the viewpoint of flattening and preventing misalignment of the semiconductor chip. In addition, from the viewpoint of forming a pressure-sensitive adhesive sheet that can be easily peeled off with a slight force when peeling off, it is preferably 1,000 or less, more preferably 200 or less, still more preferably 60 or less, and still more preferably 30 or less.
The thickness of the first pressure-sensitive adhesive layer means a value measured by the method described in Examples.

The first pressure-sensitive adhesive layer can be formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin.
Hereinafter, each component contained in the pressure-sensitive adhesive composition which is a material for forming the first pressure-sensitive adhesive layer will be described.

<Adhesive resin>
The adhesive resin used in the present embodiment is preferably a polymer having adhesiveness by itself and a weight average molecular weight (Mw) of 10,000 or more.
The weight average molecular weight (Mw) of the adhesive resin used in the present embodiment is more preferably 10,000 to 2,000,000, further preferably 20,000 to 1.5,000,000, and still more preferably 30,000, from the viewpoint of improving the adhesive strength. ~ 1,000,000.

Examples of the adhesive resin include rubber resins such as acrylic resins, urethane resins, and polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins.
These adhesive resins may be used alone or in combination of two or more.
When these adhesive resins are copolymers having two or more types of constituent units, the form of the copolymer is not particularly limited, and a block copolymer, a random copolymer, and a graft copolymer may be used. Any of polymers may be used.

The adhesive resin used in the present embodiment may be an energy-ray-curable adhesive resin having a polymerizable functional group introduced into a side chain of the adhesive resin.
Examples of the polymerizable functional group include a (meth) acryloyl group and a vinyl group.
Examples of the energy ray include an ultraviolet ray and an electron beam, and an ultraviolet ray is preferable.

The content of the pressure-sensitive adhesive resin is preferably 30 to 99.99% by mass, more preferably 40 to 99.95% by mass, and still more preferably the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition. It is 50 to 99.90% by mass, more preferably 55 to 99.80% by mass, still more preferably 60 to 99.50% by mass.
In the following description of the present specification, "the content of each component with respect to the total amount of the active ingredients of the pressure-sensitive adhesive composition" is "the content of each component in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition" Is synonymous with

In the present embodiment, from the viewpoint of developing excellent adhesive strength, and from the viewpoint of easily forming irregularities on the surface of the formed pressure-sensitive adhesive layer by the expansion of the expandable particles in the expandable base material due to the heat treatment, The adhesive resin preferably contains an acrylic resin.
The content of the acrylic resin in the adhesive resin is preferably from 30 to 100% by mass, more preferably from 50 to 100% by mass, based on the total amount (100% by mass) of the adhesive resin contained in the adhesive composition. %, More preferably 70 to 100% by mass, even more preferably 85 to 100% by mass.

(Acrylic resin)
In the present embodiment, examples of the acrylic resin that can be used as the adhesive resin include, for example, a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, and a cyclic structure. A polymer containing a structural unit derived from (meth) acrylate is exemplified.

  The weight average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1.5 million, more preferably 200,000 to 1.3 million, further preferably 350,000 to 1.2 million, and still more preferably 500,000 to 1.1 million.

  Examples of the acrylic resin include a structural unit (a1) derived from an alkyl (meth) acrylate (a1 ′) (hereinafter, also referred to as “monomer (a1 ′)”) and a functional group-containing monomer (a2 ′) (hereinafter, referred to as “monomer (a)”). Acrylic copolymer (A1) having structural unit (a2) derived from (a2 ′)) is more preferable.

The number of carbon atoms in the alkyl group of the monomer (a1 ′) is preferably from 1 to 24, more preferably from 1 to 12, still more preferably from 2 to 10, and even more preferably from 4 to 8, from the viewpoint of improving adhesive properties. It is.
The alkyl group of the monomer (a1 ′) may be a straight-chain alkyl group or a branched-chain alkyl group.

Examples of the monomer (a1 ′) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and tridecyl ( (Meth) acrylate, stearyl (meth) acrylate and the like.
These monomers (a1 ′) may be used alone or in combination of two or more.
As the monomer (a1 ′), butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.

  The content of the structural unit (a1) is preferably from 50 to 99.9% by mass, more preferably from 60 to 99.0% by mass based on all the structural units (100% by mass) of the acrylic copolymer (A1). %, More preferably 70 to 97.0% by mass, even more preferably 80 to 95.0% by mass.

Examples of the functional group of the monomer (a2 ′) include a hydroxyl group, a carboxy group, an amino group, and an epoxy group.
That is, examples of the monomer (a2 ′) include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer.
These monomers (a2 ′) may be used alone or in combination of two or more.
Among these, as the monomer (a2 ′), a hydroxyl group-containing monomer and a carboxy group-containing monomer are preferable.

  Examples of the hydroxyl group-containing monomer include, for example, the same as the above-mentioned hydroxyl group-containing compound.

  Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; and ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and anhydrides thereof. , 2- (acryloyloxy) ethyl succinate, 2-carboxyethyl (meth) acrylate and the like.

  The content of the structural unit (a2) is preferably from 0.1 to 40% by mass, more preferably from 0.5 to 35% by mass, based on all the structural units (100% by mass) of the acrylic copolymer (A1). %, More preferably 1.0 to 30% by mass, even more preferably 3.0 to 25% by mass.

The acrylic copolymer (A1) may further have a structural unit (a3) derived from another monomer (a3 ′) other than the monomers (a1 ′) and (a2 ′).
In the acrylic copolymer (A1), the content of the structural units (a1) and (a2) is preferably 70% based on all the structural units (100% by mass) of the acrylic copolymer (A1). To 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass.

  Examples of the monomer (a3 ′) include olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene and chloroprene; cyclohexyl (meth) acrylate; It has a cyclic structure such as benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and imide (meth) acrylate. (Meth) acrylate; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmo Holin, N- vinylpyrrolidone and the like.

Further, the acrylic copolymer (A1) may be an energy ray-curable acrylic copolymer having a polymerizable functional group introduced into a side chain.
The polymerizable functional group and the energy ray are as described above.
The polymerizable functional group is an acrylic copolymer having the above-mentioned structural units (a1) and (a2), and a substituent capable of bonding to the functional group of the structural unit (a2) of the acrylic copolymer. And a compound having a polymerizable functional group.
Examples of the compound include (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, and glycidyl (meth) acrylate.

<Crosslinking agent>
In the present embodiment, when the pressure-sensitive adhesive composition contains a pressure-sensitive resin having a functional group such as the above-mentioned acrylic copolymer (A1), it is preferable that the pressure-sensitive adhesive composition further contains a crosslinking agent.
The crosslinking agent reacts with the adhesive resin having a functional group, and crosslinks the adhesive resins with the functional group as a crosslinking starting point.

Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent.
These crosslinking agents may be used alone or in combination of two or more.
Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoint of increasing the cohesive force to improve the adhesive strength and from the viewpoint of easy availability.

  The content of the crosslinking agent is appropriately adjusted depending on the number of functional groups of the adhesive resin, preferably 0.01 to 10 parts by mass, based on 100 parts by mass of the adhesive resin having a functional group. It is more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 to 5 parts by mass.

<Tackifier>
In the present embodiment, the pressure-sensitive adhesive composition may further contain a tackifier from the viewpoint of further improving the adhesive strength.
In the present specification, the “tackifier” is a component that assists in improving the adhesive strength of the above-mentioned adhesive resin, and refers to an oligomer having a mass average molecular weight (Mw) of less than 10,000, It is distinguished from the conductive resin.
The weight average molecular weight (Mw) of the tackifier is preferably from 400 to 10,000, more preferably from 500 to 8,000, and still more preferably from 800 to 5,000.

  As the tackifier, for example, a rosin-based resin, a terpene-based resin, a styrene-based resin, a pentene produced by the thermal decomposition of petroleum naphtha, a copolymer of a C5 fraction such as isoprene, piperine, and 1,3-pentadiene are obtained. C5 petroleum resin obtained, a C9 petroleum resin obtained by copolymerizing a C9 fraction such as indene and vinyltoluene generated by thermal decomposition of petroleum naphtha, and a hydrogenated resin obtained by hydrogenating these.

The softening point of the tackifier is preferably from 60 to 170C, more preferably from 65 to 160C, and still more preferably from 70 to 150C.
In addition, in this specification, the "softening point" of a tackifier means the value measured based on JISK2531.
The tackifiers may be used alone or in combination of two or more having different softening points, structures, and the like.
When two or more tackifiers are used, the weighted average of the softening points of the tackifiers preferably falls within the above range.

  The content of the tackifier is preferably 0.01 to 65% by mass, more preferably 0.05 to 55% by mass, and still more preferably the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition. It is 0.1 to 50% by mass, more preferably 0.5 to 45% by mass, and still more preferably 1.0 to 40% by mass.

<Photopolymerization initiator>
In this embodiment, when the pressure-sensitive adhesive composition includes an energy-ray-curable pressure-sensitive adhesive resin as the pressure-sensitive resin, it is preferable that the pressure-sensitive adhesive composition further contains a photopolymerization initiator.
By making the pressure-sensitive adhesive composition containing an energy ray-curable pressure-sensitive adhesive resin and a photopolymerization initiator, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition can be irradiated with relatively low-energy energy rays, It is possible to sufficiently advance the curing reaction and adjust the adhesive strength to a desired range.
In addition, as a photopolymerization initiator, the same thing as what is mix | blended with the above-mentioned solventless resin composition (y1) is mentioned.

  The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the energy ray-curable adhesive resin. 05 to 2 parts by mass.

<Adhesive additive>
In the present embodiment, the pressure-sensitive adhesive composition that is a material for forming the first pressure-sensitive adhesive layer is a pressure-sensitive adhesive that is used as a general pressure-sensitive adhesive, in addition to the above-described additives, as long as the effects of the present invention are not impaired. May be contained.
Examples of such additives for pressure-sensitive adhesives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), and ultraviolet absorbers.
These pressure-sensitive adhesive additives may be used alone or in combination of two or more.

  When these adhesive additives are contained, the content of each adhesive additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001 part by mass, based on 100 parts by mass of the adhesive resin. To 10 parts by mass.

The pressure-sensitive adhesive composition, which is a material for forming the pressure-sensitive adhesive layer, may contain expandable particles as long as the effects of the present invention are not impaired.
However, as described above, the first pressure-sensitive adhesive layer is preferably a non-expandable pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive composition that is a material for forming the pressure-sensitive adhesive layer is preferably as small as possible in the content of the expandable particles.
The content of the expandable particles is preferably less than 5% by mass, more preferably less than 1% by mass, and still more preferably less than 0.1% by mass, based on the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition. , Even more preferably less than 0.01% by mass, particularly preferably less than 0.001% by mass.

(Second adhesive layer)
The second pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet of the present embodiment may be any as long as it contains a pressure-sensitive resin, and if necessary, a pressure-sensitive adhesive such as a crosslinking agent, a tackifier, a polymerizable compound, or a polymerization initiator. It may contain additives.
Preferred embodiments of the composition and form of the second pressure-sensitive adhesive layer are the same as those of the first pressure-sensitive adhesive layer. However, the compositions of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be the same or different. Further, the forms of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be the same or different.
The storage shear modulus G ′ (23) of the second pressure-sensitive adhesive layer is preferably from 1.0 × 10 ^{4 to} 1.0 × 10 ⁸ Pa, from the viewpoint of improving the adhesion to a support or the like. preferably ^{3.0 × 10 4 ~5.0 × 10 7} Pa, more preferably from ^{5.0 × 10 4 ~1.0 × 10 7} Pa.

(Release material)
As in the pressure-sensitive adhesive sheet 10a of FIG. 1B, the pressure-sensitive adhesive sheet of the present embodiment may further have a release material on the pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer.
As the release material, a release sheet that has been subjected to a double-sided release treatment, a release sheet that has been subjected to a single-sided release treatment, or the like is used.

  Examples of the base material for the release material include papers such as high-quality paper, glassine paper, and kraft paper; polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; polypropylene resins; and polyethylene resins. And plastic films such as olefin resin films.

  Examples of the release agent include a rubber-based elastomer such as a silicone-based resin, an olefin-based resin, an isoprene-based resin, and a butadiene-based resin, a long-chain alkyl-based resin, an alkyd-based resin, and a fluorine-based resin.

  The thickness of the release material is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 170 μm, and still more preferably 35 to 80 μm.

(Production method of adhesive sheet)
The method for producing the double-sided pressure-sensitive adhesive sheet according to this embodiment is not particularly limited, and includes, for example, a production method (a) having the following steps (1a) to (4a).
Step (1a): On the release-treated surface of the release material, apply a resin composition (y), which is a material for forming the expansive base material, to form a coating film, and then dry or UV cure the coating film. And a step of peeling the release material from the obtained expandable base material.
Step (2a): forming a coating by applying a pressure-sensitive adhesive composition that is a material for forming the first pressure-sensitive adhesive layer on a release-treated surface of a release material different from step (1a); Drying to form a first pressure-sensitive adhesive layer.
Step (3a): A pressure-sensitive adhesive composition, which is a material for forming the second pressure-sensitive adhesive layer, is applied on a release-treated surface of a release material different from the steps (1a) and (2a) to form a coating film. Drying the coating film to form a second pressure-sensitive adhesive layer.
Step (4a): a step of attaching a first adhesive layer to one surface of the expandable base material formed in step (1a) and attaching a second adhesive layer to the other surface.

As another method for producing the double-sided pressure-sensitive adhesive sheet according to the present embodiment, a production method (b) having the following steps (1b) to (3b) is exemplified.
Step (1b): A coating composition is formed by applying a pressure-sensitive adhesive composition that is a material for forming the first pressure-sensitive adhesive layer on the release-treated surface of the release material, and the coating film is dried, and the first pressure-sensitive adhesive is dried. Forming a layer;
Step (2b): A resin composition (y), which is a material for forming an expandable base material, is applied on the surface of the formed first pressure-sensitive adhesive layer to form a coating film, and the coating film is dried or UV-coated. Curing and forming an expandable substrate.
Step (3b): A pressure-sensitive adhesive composition as a material for forming a second pressure-sensitive adhesive layer is applied on the surface of the formed expandable base material to form a coating film, and the coating film is dried. 2 Step of forming an adhesive layer.

In the above production methods (a) and (b), the resin composition (y) and the pressure-sensitive adhesive composition may be further mixed with a diluting solvent to form a solution.
Examples of the coating method include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.

  The drying or UV irradiation for forming the intumescent substrate from the coating film in the step (1a) of the production method (a) and the step (1b) in the production method (b) may be performed under conditions where the intumescent particles do not expand. It is preferable to select and carry out. For example, when drying the resin composition (y) containing the heat-expandable particles to form an expandable substrate, the drying is preferably performed at a temperature lower than the expansion start temperature (t) of the heat-expandable particles.

<Each manufacturing process of the semiconductor device according to the present embodiment>
Next, each step of the method for manufacturing a semiconductor device according to the present embodiment will be described.
The method for manufacturing a semiconductor device according to this embodiment is a method for manufacturing a semiconductor device using the double-sided pressure-sensitive adhesive sheet, and includes the following steps (1) to (4).
Step (1): a step of attaching a hard support to the adhesive surface of the second adhesive layer Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the first adhesive layer Step (3) ): The semiconductor chip and the peripheral portion of the semiconductor chip on the adhesive surface of the first adhesive layer are covered with a sealing material, and the sealing material is cured to cure and seal the semiconductor chip. Step of obtaining a cured sealing body sealed with a material Step (4): a step of expanding the expandable particles and peeling the double-sided pressure-sensitive adhesive sheet from the cured sealing body Each step of the method for manufacturing a semiconductor device according to the embodiment will be described.

(Step (1))
FIG. 2A is a cross-sectional view illustrating a step (1) of attaching the hard support 20 to the adhesive surface 122a of the second adhesive layer 122 of the double-sided adhesive sheet 10.
When the double-sided pressure-sensitive adhesive sheet 10 has the release material 132, the release material 132 is peeled in advance.

The rigid support 20 is attached to the adhesive surface 122a of the second adhesive layer 122, and is used for the purpose of obtaining a cured sealing body having excellent flatness in the steps (2) and (3). It is.
From the viewpoint of fulfilling the above-mentioned purpose, it is preferable that the rigid support 20 is attached to the entire surface of the adhesive surface 122 (a) as shown in FIG. Therefore, the hard support 20 is preferably plate-shaped, and the area of the surface on the side to be attached to the adhesive surface 122a is preferably equal to or greater than the area of the adhesive surface 122a.
The material of the hard support 20 may be appropriately determined in consideration of mechanical strength, heat resistance, and the like. For example, a metal material such as SUS; a nonmetallic inorganic material such as glass and silicon wear; a polyimide and a polyamideimide; Resin materials; composite materials such as glass epoxy resin, etc .; and among them, SUS, glass, silicon wafer, and the like are preferable.
The thickness of the hard support 20 may be appropriately determined in consideration of mechanical strength, handleability, and the like, and is, for example, 100 μm to 50 mm.

(Step (2))
FIG. 2B is a cross-sectional view illustrating a step (2) of mounting the semiconductor chip CP on a part of the adhesive surface 121a of the first adhesive layer 121.
When the double-sided pressure-sensitive adhesive sheet 10 has the release material 131, the release material 131 is peeled in advance.
A conventionally known semiconductor chip CP can be used. In the semiconductor chip CP, an integrated circuit including circuit elements such as transistors, resistors, and capacitors is formed on the circuit surface W1.
The semiconductor chip CP is placed, for example, such that the circuit surface W1 is covered with the adhesive surface 121a. For mounting the semiconductor chip CP, a known device such as a flip chip bonder or a die bonder can be used.
The layout of the semiconductor chips CP, the number of the semiconductor chips CP, and the like may be determined as appropriate according to the form of the target package, the number of products to be manufactured, and the like.
Here, the method for manufacturing a semiconductor device according to the present embodiment covers the semiconductor chip CP with an encapsulant in a region larger than the chip size, such as FOWLP, FOPLP, etc. Instead, the present invention is suitably applied to a package in which a rewiring layer is formed even in the surface region of the sealing material. Therefore, the semiconductor chip CP is placed on a part of the adhesive surface 121a of the first adhesive layer 121, and the plurality of semiconductor chips CP are aligned at regular intervals and are arranged on the adhesive surface 121a. It is more preferable that the plurality of semiconductor chips CP are mounted on the adhesive surface 121a in a state of being arranged in a matrix of a plurality of rows and a plurality of columns at a predetermined interval. The distance between the semiconductor chips CP may be appropriately determined according to the intended form of the package and the like.
By placing the semiconductor chip CP on a part of the adhesive surface 121a of the first adhesive layer 121, the peripheral portion 30 of the semiconductor chip CP is formed on the adhesive surface 121a of the first adhesive layer 121. . In FIG. 2B, the peripheral portion 30 of the semiconductor chip CP is the adhesive surface 121a of the first adhesive layer 121 corresponding to the gap between the adjacent semiconductor chips CP among the plurality of semiconductor chips CP.

(Step (3))
2C and 2D, the semiconductor chip CP and the peripheral portion 30 of the semiconductor chip CP in the adhesive surface 121a of the first adhesive layer 121 are covered with a sealing material 40. A cross-sectional view illustrating a step (3) of curing the stopper 40 to obtain a cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41 is shown.
Hereinafter, the step of covering the semiconductor chip CP and the peripheral portion 30 of the semiconductor chip CP in the adhesive surface 121a of the first adhesive layer 121 with the sealing material 40 may be referred to as a “covering step”. The step of curing the sealing material 40 to obtain a cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41 may be referred to as a “curing step”.

  As shown in FIG. 2C, in the covering step, first, the semiconductor chip CP and the peripheral portion 30 of the semiconductor chip CP on the adhesive surface 121 a of the first adhesive layer 121 are sealed with the sealing material 40. Cover. The sealing material 40 covers the entire exposed surface of the semiconductor chip CP and also fills a gap between the plurality of semiconductor chips CP.

The sealing material 40 has a function of protecting the semiconductor chip CP and its associated components from the external environment.
The sealing material 40 is not particularly limited, and any material can be appropriately selected from those conventionally used as semiconductor sealing materials.
The sealing material 40 has curability from the viewpoint of mechanical strength, heat resistance, insulation properties, and the like, and examples thereof include a thermosetting resin composition and an energy ray-curable resin composition.
Hereinafter, in the present embodiment, description will be made assuming that the sealing material 40 is a thermosetting resin composition.

Examples of the thermosetting resin contained in the thermosetting resin composition as the sealing material 40 include an epoxy resin, a phenol resin, and a cyanate resin. In view of the above, an epoxy resin is preferable.
The thermosetting resin composition, in addition to the thermosetting resin, if necessary, a phenolic resin-based curing agent, a curing agent such as an amine-based curing agent, a curing accelerator, an inorganic filler such as silica, An additive such as an elastomer may be contained.
The sealing material 40 may be solid or liquid at room temperature. The form of the sealing material 40 that is solid at room temperature is not particularly limited, and may be, for example, a granular form, a sheet form, or the like.

As a method of covering the semiconductor chip CP and the peripheral portion 30 with the sealing material 40, any method can be appropriately selected from the methods conventionally applied to the semiconductor sealing step and applied. For example, a roll laminating method, a vacuum pressing method, a vacuum laminating method, a spin coating method, a die coating method, a transfer molding method, a compression molding method, and the like can be applied.
In these methods, usually, the sealing material 40 is heated at the time of coating to impart fluidity in order to enhance the filling property of the sealing material 40.

As shown in FIG. 2D, after performing the covering step, the sealing material 40 is cured to obtain a cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41.
Here, as described above, the double-sided pressure-sensitive adhesive sheet 10 used in the present embodiment contains expandable particles that expand due to heat, energy rays, and the like. In step (4) described below, the expandable particles are used. Is expanded to reduce the adhesive strength between the adhesive surface 121a and the cured sealing body 50, and the double-sided adhesive sheet 10 is peeled from the cured sealing body 50. Therefore, in the covering step and the curing step, it is preferable to appropriately select conditions under which the expandable particles do not expand, and to cover and cure the sealing material 40.
For example, when the expandable particles contained in the double-sided pressure-sensitive adhesive sheet 10 are heat-expandable particles, the heating conditions (heating temperature and heating time) in the coating step and the curing step are determined by the double-sided pressure-sensitive adhesive sheet caused by the expansion of the heat-expandable particles. Heating conditions in which the rate of increase in thickness of 10 is 10% or less are preferable, heating conditions in which the rate of increase is 5% or less are more preferable, and heating conditions in which the rate of increase is 0% (that is, the heat-expandable particles). Is preferable, under which heating does not expand. The rate of increase in the thickness of the double-sided pressure-sensitive adhesive sheet 10 can be determined, for example, by measuring the thickness of the double-sided pressure-sensitive adhesive sheet 10 before and after heating under predetermined conditions according to JIS K6783, Z1702, and Z1709. It can be calculated based on the following formula by measuring using Teklock product name “PG-02”).
Rate of increase in thickness (%) = (thickness after heating−thickness before heating) × 100 / thickness before heating The coating step and the curing step may be performed separately. When heating the sealing material 40, the heating may cure the sealing material 40 as it is. That is, in that case, the coating step and the curing step may be performed simultaneously.

  In the present embodiment, a mode is described in which the thermosetting resin composition is used as the sealing material 40 and the heat-expandable particles are used as the expandable particles. Is an expandable resin composition, in which the expandable particles are thermally expandable particles, and in which the sealing material 40 is an energy ray-curable resin composition, and the expandable particles are energy ray expandable particles. Also in these embodiments, it is preferable that the rate of increase in the thickness of the double-sided PSA sheet 10 in the coating step and the curing step satisfies the above-described range.

Specific examples of the temperature at which the thermosetting resin composition is heated in the coating step vary depending on the type of the sealing material 40 used, the type of the expandable particles, and the like. 170 ° C is preferable, and 70 to 150 ° C is more preferable. The heating time is, for example, 5 seconds to 60 minutes, preferably 10 seconds to 45 minutes, and more preferably 15 seconds to 30 minutes.
In the curing step, a specific example of the temperature at which the sealing material 40 is cured varies depending on the type of the sealing material 40 to be used, the type of the expandable particles, and the like, but is, for example, 80 to 240 ° C and 90 to 200 ° C. C is preferable, and 100 to 170C is more preferable. The heating time is, for example, 10 to 180 minutes, preferably 20 to 150 minutes, and more preferably 30 to 120 minutes.

In the present embodiment, it is preferable to perform the covering step and the curing step using a sheet-shaped sealing material (hereinafter, also referred to as “sheet-shaped sealing material”).
In the method using a sheet-shaped sealing material, the semiconductor chip CP and its peripheral portion 30 are covered with the sealing material 40 by placing the sheet-shaped sealing material so as to cover the semiconductor chip CP and its peripheral portion 30. . At this time, it is preferable to perform heating and pressure bonding by a vacuum laminating method or the like while appropriately reducing the pressure so that a portion in which the sealing material 40 is not filled does not occur in a gap between the semiconductor chips CP. Preferred embodiments of the conditions of reduced pressure, heating and pressure bonding are as described above. Thereafter, the laminated sealing material 40 is heated and cured. Preferred embodiments of the curing temperature are as described above.
The sheet-shaped sealing material may be a laminated sheet supported by a resin sheet such as polyethylene terephthalate. In this case, the resin sheet may be peeled off from the sealing material after the laminated sheet is placed so that the sheet-shaped sealing material covers the semiconductor chip CP and the peripheral portion 30 thereof.

  By the step (3), the cured sealing body 50 in which the plurality of semiconductor chips CP separated by the predetermined distance are embedded in the cured sealing material 41 is obtained.

(Step (4))
FIG. 2E is a cross-sectional view illustrating a step (4) of expanding the expandable particles and peeling the double-sided pressure-sensitive adhesive sheet 10 from the cured sealing body 50.
Specifically, the expandable particles are expanded by heat, energy rays, or the like in accordance with the type of the expandable particles to form irregularities on the adhesive surface 121a of the first adhesive layer 121. The adhesive strength with the cured sealing body 50 is reduced, and the double-sided adhesive sheet 10 is peeled off.
At this time, according to the manufacturing method according to the present embodiment, since the hard support 20 is attached to the adhesive surface 122a of the second adhesive layer 122, the unevenness is formed on the adhesive surface 122a side of the second adhesive layer 122. Is suppressed, whereby unevenness can be efficiently formed on the adhesive surface 121a side of the first adhesive layer 121, and excellent peelability can be obtained.
The method of expanding the expandable particles may be appropriately selected according to the type of the expandable particles.
When the expandable particles are thermally expandable particles, they may be heated to a temperature equal to or higher than the expansion start temperature (t). Here, the “temperature equal to or higher than the expansion start temperature (t)” is preferably equal to or higher than “expansion start temperature (t) + 10 ° C.” and equal to or lower than “expansion start temperature (t) + 60 ° C.”. (t) + 15 ° C. ”or more and“ expansion start temperature (t) + 40 ° C. ”or less. Specifically, the particles may be expanded by heating, for example, in the range of 120 to 250 ° C. according to the type of the thermally expandable particles.

  After expanding the expandable particles, the double-sided pressure-sensitive adhesive sheet 10 is peeled off from the cured sealing body 50. Since the double-sided pressure-sensitive adhesive sheet 10 according to the present embodiment has excellent peelability, it can be peeled with a smaller external force than a conventional temporary fixing sheet. The method of peeling is not particularly limited, and for example, a method of peeling from the cured sealing body 50 from the double-sided pressure-sensitive adhesive sheet 10 using a debonder is exemplified.

  In the manufacturing method according to this embodiment, in step (4), before or after peeling the double-sided pressure-sensitive adhesive sheet 10 from the cured sealing body 50, if necessary, the thickness of the cured sealing body 50 is reduced. In order to do so, a grinding step may be included.

(Step (5))
The manufacturing method according to the present embodiment preferably includes a step (5) of forming a rewiring layer on the cured sealing body 50 from which the double-sided pressure-sensitive adhesive sheet 10 has been peeled off.
FIG. 3A is a cross-sectional view of the cured sealing body 50 after the double-sided pressure-sensitive adhesive sheet 10 has been peeled off.
In this step, the rewiring connecting to the circuits W2 of the plurality of exposed semiconductor chips CP is formed on the circuit surface W1 and on the surface 50a of the cured sealing body 50 corresponding to the area outside the semiconductor chip CP. .

FIG. 3B is a cross-sectional view illustrating a step of forming the first insulating layer 61 on the circuit surface W1 of the semiconductor chip CP and the surface 50a of the cured sealing body 50.
A first insulating layer 61 containing an insulating resin is formed on the circuit surface W1 and the surface 50a so as to expose the circuit W2 of the semiconductor chip CP or the internal terminal electrode W3 of the circuit W2. Examples of the insulating resin include a polyimide resin, a polybenzoxazole resin, and a silicone resin. The material of the internal terminal electrode W3 is not limited as long as it is a conductive material, and examples thereof include metals such as gold, silver, copper, and aluminum, and alloys including these metals.

FIG. 3C is a cross-sectional view illustrating a step of forming a rewiring 70 electrically connected to the semiconductor chip CP sealed in the cured sealing body 50.
In the present embodiment, the rewiring 70 is formed following the formation of the first insulating layer 61. The material of the rewiring 70 is not limited as long as it is a conductive material, and examples thereof include metals such as gold, silver, copper, and aluminum, and alloys including these metals. The rewiring 70 can be formed by a known method such as a subtractive method or a semi-additive method.

FIG. 4A is a cross-sectional view illustrating a step of forming a second insulating layer 62 that covers the rewiring 70.
The rewiring 70 has an external electrode pad 70A for an external terminal electrode. An opening or the like is provided in the second insulating layer 62 to expose the external electrode pad 70A for the external terminal electrode. In the present embodiment, the external electrode pads 70A are located inside and outside the region (the region corresponding to the circuit surface W1) of the semiconductor chip CP of the cured sealing body 50 (the region corresponding to the surface 50a on the cured sealing body 50). It is exposed to. The rewiring 70 is formed on the surface 50a of the cured sealing body 50 so that the external electrode pads 70A are arranged in an array. In the present embodiment, since the external electrode pad 70A is exposed outside the region of the semiconductor chip CP of the cured sealing body 50, FOWLP or FOPLP can be obtained.

(Connection process with external terminal electrode)
FIG. 4B is a cross-sectional view illustrating a step of connecting the external terminal electrode 80 to the external electrode pad 70A.
An external terminal electrode 80 such as a solder ball is mounted on the external electrode pad 70A exposed from the second insulating layer 62, and the external terminal electrode 80 and the external electrode pad 70A are electrically connected by soldering or the like. The material of the solder ball is not particularly limited, and examples thereof include lead-containing solder and lead-free solder.

(Dicing process)
FIG. 4C is a cross-sectional view illustrating a step of separating the cured sealing body 50 to which the external terminal electrode 80 is connected.
In this step, the cured sealing body 50 is divided into individual semiconductor chips CP. The method for separating the cured sealing body 50 into individual pieces is not particularly limited, and can be implemented by a cutting means such as a dicing saw.
By dividing the cured sealing body 50 into individual pieces, the semiconductor device 100 for each semiconductor chip CP is manufactured. As described above, the semiconductor device 100 in which the external terminal electrode 80 is connected to the external electrode pad 70A fanned out of the area of the semiconductor chip CP is manufactured as FOWLP, FOPLP, or the like.

(Mounting process)
In the present embodiment, it is also preferable to include a step of mounting the singulated semiconductor device 100 on a printed wiring board or the like.

  The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples. The physical properties in the following Production Examples and Examples are values measured by the following methods.

<Mass average molecular weight (Mw)>
Using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020"), the value was measured under the following conditions, and the value measured in terms of standard polystyrene was used.
(Measurement condition)
-Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", "TSK gel G1000HXL" (all manufactured by Tosoh Corporation)-Column temperature: 40 ° C
・ Developing solvent: tetrahydrofuran ・ Flow rate: 1.0 mL / min

<Measurement of thickness of each layer>
The thickness was measured using a constant-pressure thickness measuring instrument (model number: “PG-02J”, standard: JIS K6783, Z1702, Z1709) manufactured by TECLOCK Co., Ltd.

<Average particle diameter (D ₅₀ ), 90% particle diameter (D ₉₀ ) of thermally expandable particles>
The particle distribution of the thermally expandable particles before expansion at 23 ° C. was measured using a laser diffraction type particle size distribution analyzer (for example, product name “Master Sizer 3000” manufactured by Malvern).
The particle diameters corresponding to 50% and 90% of the cumulative volume frequency calculated from the smaller particle diameter of the particle distribution are referred to as “average particle diameter of thermally expandable particles (D ₅₀ )” and “thermally expandable particles,” respectively. 90% particle size (D ₉₀ ).

<Storage modulus E ′ of expansive substrate>
When the measurement object was a non-adhesive expandable base material, the expandable base material had a size of 5 mm in length × 30 mm in width × 200 μm in thickness, and a test sample was obtained by removing the release material.
Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments Co., Ltd., product name "DMAQ800"), the test start temperature is 0 ° C., the test end temperature is 300 ° C., the heating rate is 3 ° C./min, the frequency is 1 Hz, and the amplitude is 20 μm. The storage elastic modulus E 'of the test sample at a predetermined temperature was measured under the following conditions.

<Storage shear modulus G ′ of pressure-sensitive adhesive layer, storage modulus E ′ of expansive pressure-sensitive adhesive layer>
When the measurement object is an expandable pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer having tackiness, the expandable pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer have a diameter of 8 mm x a thickness of 3 mm, and a sample from which the release material has been removed is used as a test sample. .
Using a viscoelasticity measuring device (manufactured by Anton Paar, device name "MCR300"), a test start temperature of 0 ° C, a test end temperature of 300 ° C, a heating rate of 3 ° C / min, and a frequency of 1 Hz were used for a torsional shear method. The storage shear modulus G ′ of the test sample at a predetermined temperature was measured.
Then, the value of the storage elastic modulus E ′ was calculated from the approximate expression “E ′ = 3G ′” based on the measured value of the storage shear modulus G ′.

<Probe tack value>
After cutting the expandable base material or the expandable pressure-sensitive adhesive layer to be measured into a square having a side of 10 mm, the cut was allowed to stand at 23 ° C. and 50% RH (relative humidity) for 24 hours to remove the light release film. These were used as test samples.
In an environment of 23 ° C. and 50% RH (relative humidity), a light-peeling film was removed using a tacking tester (manufactured by Nippon Tokusiki Co., Ltd., product name “NTS-4800”), and the surface was exposed. The probe tack value on the surface of the test sample was measured according to JIS Z0237: 1991.
Specifically, after a stainless steel probe having a diameter of 5 mm was brought into contact with the surface of the test sample for 1 second at a contact load of 0.98 N / cm ² , the probe was brought into contact with the test sample at a speed of 10 mm / sec. The force required to separate from the surface was measured. Then, the measured value was used as the probe tack value of the test sample.

The details of the adhesive resin, additives, thermally expandable particles, and release material used in the following production examples are as follows.
<Adhesive resin>
Acrylic copolymer (i): having a structural unit derived from a raw material monomer composed of 2-ethylhexyl acrylate (2EHA) / 2-hydroxyethyl acrylate (HEA) = 80.0 / 20.0 (mass ratio). A solution containing an acrylic copolymer having a mass average molecular weight (Mw) of 600,000. Diluent solvent: ethyl acetate, solid content concentration: 40% by mass.
Acrylic copolymer (ii): n-butyl acrylate (BA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) / acrylic acid = 86.0 / 8.0 / 5.0 / 1. A solution containing an acrylic copolymer having a mass average molecular weight (Mw) of 600,000 and having a constitutional unit derived from a raw material monomer having a mass ratio of 0 (mass ratio). Diluent solvent: ethyl acetate, solid content concentration: 40% by mass.
<Additives>
-Isocyanate crosslinking agent (i): manufactured by Tosoh Corporation, product name "Coronate L", solid content concentration: 75% by mass.
-Photopolymerization initiator (i): manufactured by BASF, product name "Irgacure 184", 1-hydroxy-cyclohexyl-phenyl-ketone.
<Thermal expandable particles>
Thermal expansion particles (i): Kureha Corporation, product name “S2640”, expansion start temperature (t) = 208 ° C., average particle diameter (D ₅₀ ) = 24 μm, 90% particle diameter (D ₉₀ ) = 49 μm .
<Release material>
-Heavy release film: manufactured by Lintec Co., Ltd., product name "SP-PET382150", a polyethylene terephthalate (PET) film provided with a release agent layer formed of a silicone release agent on one surface, thickness: 38 m.
-Light release film: manufactured by Lintec Co., Ltd., product name "SP-PET381031", a PET film provided with a release agent layer formed of a silicone release agent on one surface, thickness: 38 m.

Production Example 1 (Formation of First Adhesive Layer (X-1))
100 parts by mass of the solid content of the acrylic copolymer (i), which is an adhesive resin, was mixed with 5.0 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i), and diluted with toluene. By stirring uniformly, a composition (x-1) having a solid content concentration (active ingredient concentration) of 25% by mass was prepared.
Then, the prepared composition (x-1) is applied on the surface of the release agent layer of the heavy release film to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to have a thickness of 10 μm. Of the first pressure-sensitive adhesive layer (X-1) was formed.
In addition, the storage shear elastic modulus G ′ (23) of the first pressure-sensitive adhesive layer (X-1) at 23 ° C. was 2.5 × 10 ⁵ Pa.

Production Example 2 (formation of second pressure-sensitive adhesive layer (X-2))
0.8 part by mass (solid content ratio) of the isocyanate-based cross-linking agent (i) is mixed with 100 parts by mass of the solid content of the acrylic copolymer (ii), which is an adhesive resin, and diluted with toluene, The composition was uniformly stirred to prepare a composition (x-2) having a solid content concentration (active ingredient concentration) of 25% by mass.
Then, on the surface of the release agent layer of the light release film, the prepared composition (x-2) is applied to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to have a thickness of 10 μm. Of the second pressure-sensitive adhesive layer (X-2).
The storage shear modulus G ′ (23) of the second pressure-sensitive adhesive layer (X-2) at 23 ° C. was 9.0 × 10 ⁴ Pa.

Production Example 3 (Formation of expandable base material (Y-1))
(1) Preparation of composition (y-1) Ester-type diol and terminal isocyanate urethane prepolymer obtained by reacting isophorone diisocyanate (IPDI) are reacted with 2-hydroxyethyl acrylate to obtain a mass average molecular weight ( Mw) 5000 bifunctional acrylic urethane-based oligomer was obtained.
Then, 40% by mass (solids ratio) of isobornyl acrylate (IBXA) and 40% by mass (solids ratio) of acryl urethane-based oligomer (solid content ratio) and phenylhydroxypropyl acrylate (HPPA) as energy ray polymerizable monomers were synthesized. ) 20% by mass (solid content ratio), and based on 100 parts by mass of the total amount of the acrylic urethane-based oligomer and the energy ray-polymerizable monomer, 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF; 2.0 parts by mass (solid content ratio) of a product name "Irgacure 184") and 0.2 parts by mass (solid content ratio) of a phthalocyanine pigment as an additive were prepared to prepare an energy ray-curable composition. .
Then, the heat-expandable particles (i) were blended with the energy ray-curable composition to prepare a solvent-free composition (y-1) containing no solvent.
The content of the thermally expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the composition (y-1).

(2) Formation of expandable base material (Y-1) The prepared composition (y-1) was applied on the surface of the release agent layer of the light release film to form a coating film.
Then, using an ultraviolet irradiation device (product name “ECS-401GX” manufactured by Eye Graphics Co., Ltd.) and a high-pressure mercury lamp (product name “H04-L41” manufactured by Eye Graphics Co., Ltd.), illuminance 160 mW / cm ² , light amount 500 mJ / The coating film was cured by irradiating ultraviolet rays under the condition of cm ² to form an expandable base material (Y-1) having a thickness of 50 μm. The above-mentioned illuminance and light amount at the time of ultraviolet irradiation are values measured using an illuminance / light amount meter (product name “UV Power Pack II” manufactured by EIT).

Production Example 4 (Formation of expandable base material (Y-2))
(1) Synthesis of urethane prepolymer In a reaction vessel under a nitrogen atmosphere, isophorone diisocyanate (IPDI) was mixed with carbonate based on 100 parts by mass (solid content ratio) of a carbonate-type diol having a mass average molecular weight (Mw) of 1,000. The hydroxyl group of the type diol and the isocyanate group of isophorone diisocyanate were blended such that the equivalent ratio became 1/1, and 160 parts by mass of toluene was further added. Under a nitrogen atmosphere, the isocyanate group concentration was reduced to the theoretical amount while stirring. The reaction was carried out at 80 ° C. for 6 hours or more until the temperature reached.
Next, a solution prepared by diluting 1.44 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA) in 30 parts by mass of toluene was added, and the mixture was further heated at 80 ° C. until the isocyanate groups at both ends disappeared. The reaction was carried out for 6 hours to obtain a urethane prepolymer having a mass average molecular weight (Mw) of 29,000.

(2) Synthesis of acrylic urethane resin In a reaction vessel under a nitrogen atmosphere, 100 parts by mass (solid content ratio) of the urethane prepolymer obtained in the above (1), 117 parts by mass of methyl methacrylate (MMA) (solid content ratio) , 2-hydroxyethyl methacrylate (2-HEMA) 5.1 parts by mass (solids ratio), 1-thioglycerol 1.1 parts by mass (solids ratio), and toluene 50 parts by mass were added, and the mixture was stirred. The temperature was raised to ° C.
Then, a solution obtained by further diluting 2.2 parts by mass (solid content ratio) of a radical initiator (manufactured by Nippon Finechem Co., Ltd., product name “ABN-E”) with 210 parts by mass of toluene at 105 ° C. in the reaction vessel. It dripped over 4 hours, maintaining.
After completion of the dropwise addition, the mixture was reacted at 105 ° C. for 6 hours to obtain a solution of an acrylic urethane-based resin having a weight average molecular weight (Mw) of 105,000.

(3) Formation of expandable base material (Y-2) Based on 100 parts by mass of the solid content of the solution of the acrylic urethane-based resin obtained in (2) above, 6.3 parts by mass of the isocyanate-based crosslinking agent (i). (Solid content ratio), 1.4 parts by mass of dioctyltin bis (2-ethylhexanoate) as a catalyst (solid content ratio), and the thermally expandable particles (i) were blended, diluted with toluene, and uniformly mixed. The mixture was stirred to prepare a composition (y-2) having a solid content concentration (active ingredient concentration) of 30% by mass.
The content of the heat-expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the active ingredients in the obtained composition (y-2).
Then, on the surface of the release agent layer of the light release film, the prepared composition (y-2) is applied to form a coating film, and the coating film is dried at 100 ° C. for 120 seconds to have a thickness of 50 μm. Of the expandable base material (Y-2).

Production Example 5 (Formation of expandable pressure-sensitive adhesive layer (Y-3))
To 100 parts by mass of the solid content of the acrylic copolymer (ii), which is an adhesive resin, 6.3 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i) and the thermally expandable particles ( i) was blended, diluted with toluene, and uniformly stirred to prepare a composition (y-3) having a solid content concentration (active ingredient concentration) of 30% by mass.
In addition, the content of the thermally expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the active ingredients in the obtained composition (y-3).
Then, the prepared composition (y-3) is applied on the surface of the release agent layer of the light release film to form a coating film, and the coating film is dried at 100 ° C. for 120 seconds to have a thickness of 50 μm. Of the expandable pressure-sensitive adhesive layer (Y-3).

  The expandable base materials (Y-1) to (Y-2) formed in Production Examples 3 and 4 and the expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5 were prepared based on the above-mentioned method. The storage elastic modulus E 'and the probe tack value were measured at 200 ° C., 100 ° C., and 208 ° C., which is the expansion start temperature of the thermally expandable particles used. Table 1 shows the results.

Example 1
The surfaces of the first pressure-sensitive adhesive layer (X-1) formed in Production Example 1 and the expandable base material (Y-1) formed in Production Example 3 are attached to each other to form an expandable base material (Y-1). The light release film on the side was removed, and the second pressure-sensitive adhesive layer (X-2) formed in Production Example 2 was attached to the surface of the exposed expansive substrate (Y-1).
Thereby, the pressure-sensitive adhesive sheet in which light release film / second pressure-sensitive adhesive layer (X-2) / expandable substrate (Y-1) / first pressure-sensitive adhesive layer (X-1) / heavy release film is laminated in this order (1) was produced.

Example 2
Light release film / second pressure-sensitive adhesive layer ( X-2) / expandable substrate (Y-2) / first pressure-sensitive adhesive layer (X-1) / heavy release film was laminated in this order to produce pressure-sensitive adhesive sheet (2).

Comparative Example 1
The surfaces of the second pressure-sensitive adhesive layer (X-2) formed in Production Example 2 and the expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5 were bonded to each other. Then, the light release film on the side of the expandable pressure-sensitive adhesive layer (Y-3) is removed, and the first pressure-sensitive adhesive layer formed in Production Example 1 is formed on the surface of the exposed expandable pressure-sensitive adhesive layer (Y-3). (X-1) was bonded.
Thereby, the light release film / second pressure-sensitive adhesive layer (X-2) / expandable pressure-sensitive adhesive layer (Y-3) / first pressure-sensitive adhesive layer (X-1) / heavy release film was laminated in this order. Sheet (3) was produced.

Comparative Example 2
The surface of the second pressure-sensitive adhesive layer (X-2) formed in Production Example 2 and the surface of the expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5 are bonded to each other, and a light release film / second pressure-sensitive adhesive layer is bonded. (X-2) / expandable pressure-sensitive adhesive layer (Y-3) / light release film were laminated in this order to prepare pressure-sensitive adhesive sheet (4).

  The following measurements were performed on the prepared pressure-sensitive adhesive sheets (1) to (4). Table 2 shows the results.

<Evaluation of misalignment of semiconductor chip during sealing process>
The light release film on the side of the second pressure-sensitive adhesive layer (X-2) of the prepared pressure-sensitive adhesive sheets (1) to (3) is removed, and the exposed pressure-sensitive adhesive surface of the second pressure-sensitive adhesive layer (X-2) is hardened. A SUS plate (thickness 1 mm, size: 200 mmφ) as a support was stuck.
Then, the heavy release films of the adhesive sheets (1) to (3) are removed, and a semiconductor chip (chip size: 6.4 mm × 6.4 mm) is placed on the exposed adhesive surface of the first adhesive layer (X-1). And a chip thickness of 200 μm (♯2000)) were placed at necessary intervals so that the adhesive surface and the circuit surface of the semiconductor chip were in contact with each other. Further, the light release film on the side of the expandable pressure-sensitive adhesive layer (Y-3) of the pressure-sensitive adhesive sheet (4) was removed, and the pressure-sensitive adhesive sheet (1) was placed on the exposed pressure-sensitive adhesive surface of the expandable pressure-sensitive adhesive layer (Y-3). ) To (3), a semiconductor chip was mounted.
Thereafter, a sealing resin film (sealing material) is laminated on the adhesive surface and the semiconductor chip, and the first adhesive layer is formed using a vacuum heating and pressurizing laminator (“7024HP5” manufactured by ROHM and HAAS). The adhesive surface of (X-1) and the semiconductor chip were covered with a sealing material, and the sealing material was cured to produce a cured sealing body. The sealing conditions are as follows.
・ Preheating temperature: 100 ° C for both table and diaphragm
・ Evacuation: 60 seconds ・ Dynamic press mode: 30 seconds ・ Static press mode: 10 seconds ・ Sealing temperature: 180 ° C. (Temperature lower than 208 ° C., which is the expansion start temperature of thermally expandable particles)
・ Sealing time: 60 minutes

After the sealing, the pressure-sensitive adhesive sheets (1) to (4) are heated at 240 ° C., which is equal to or higher than the expansion start temperature (208 ° C.) of the thermally expandable particles, for 3 minutes, and the cured sheets are sealed from the pressure-sensitive adhesive sheets (1) to (4). The stationary body was separated, and the semiconductor chip on the surface of the separated cured sealing body (the surface on which the rewiring layer was formed) was visually observed and observed with a microscope to confirm the presence / absence of misalignment of the semiconductor chip and evaluated according to the following criteria. .
A: No semiconductor chip was displaced by 25 μm or more before sealing.
F: A semiconductor chip having a displacement of 25 μm or more before sealing was observed.

<Evaluation of the flatness of the surface on the semiconductor chip side after the sealing step>
Using the pressure-sensitive adhesive sheets (1) to (4), a cured sealing body was produced in the same procedure as in the above “Evaluation of misalignment of the semiconductor chip in the sealing step”, and separated from the pressure-sensitive adhesive sheet.
The surface on the semiconductor chip side (the surface on which the rewiring layer is formed) of each of the prepared cured encapsulants is measured with a contact-type surface roughness meter (“SV3000” manufactured by Mitutoyo Corporation) and evaluated according to the following criteria. did.
A: No portion having a step of 2 μm or more was observed.
-F: The part where the level | step difference of 2 micrometers or more was produced was confirmed.

<Measurement of adhesive strength of adhesive sheet before and after heating>
The light release film on the side of the second pressure-sensitive adhesive layer (X-2) included in the prepared pressure-sensitive adhesive sheets (1) to (3) is removed, and the exposed pressure-sensitive adhesive surface of the second pressure-sensitive adhesive layer (X-2) is removed. And a 50 μm-thick polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name “Cosmo Shine A4100”) to form an adhesive sheet with a base material.
Then, the heavy release films of the pressure-sensitive adhesive sheets (1) to (3) are also removed, and the exposed pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer (X-1) is coated with a stainless steel plate (SUS304 No. 360 polishing) as an adherend. And left for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity) to obtain a test sample. Further, the light release film on the side of the expandable pressure-sensitive adhesive layer (Y-3) of the pressure-sensitive adhesive sheet (4) was removed, and the pressure-sensitive adhesive sheet (1) was applied to the exposed pressure-sensitive adhesive surface of the expandable pressure-sensitive adhesive layer (Y-3). A test sample was prepared in the same procedure as in (3) to (3).
Then, using the test sample described above, in an environment of 23 ° C. and 50% RH (relative humidity), at a pulling rate of 300 mm / min and a temperature of 23 ° C. by a 180 ° peeling method based on JIS Z0237: 2000. The adhesive strength was measured.
Further, the test sample is heated on a hot plate at 240 ° C., which is equal to or higher than the expansion start temperature (208 ° C.) of the thermally expandable particles, for 3 minutes. ), And the adhesive strength after heating at a temperature equal to or higher than the expansion start temperature was measured by a 180 ° peeling method at a tensile speed of 300 mm / min based on JIS Z0237: 2000.
In addition, when it was difficult to measure the adhesive strength so that it could not be attached to the stainless steel plate as the adherend, it was determined to be "measurable" and the adhesive strength was 0 (N / 25 mm).

From Table 2, according to the manufacturing method using the pressure-sensitive adhesive sheets (1) and (2) of Examples 1 and 2, the semiconductor chip has a high effect of suppressing sinking of the semiconductor chip during heating in the sealing step. No positional shift was observed, and the surface on the semiconductor chip side (the surface on which the rewiring layer was formed) after the sealing step was flat.
In addition, the adhesive sheets (1) and (2) have good adhesive strength before heating, but the adhesive strength has decreased to such a degree that measurement becomes impossible after heating at or above the expansion start temperature. Occasionally, the results confirm that the film can be easily peeled off with a small force.

  On the other hand, the pressure-sensitive adhesive sheet (3) of Comparative Example 1 and the pressure-sensitive adhesive sheet (4) of Comparative Example 2 have an expandable pressure-sensitive adhesive layer instead of an expandable base material. Of the semiconductor chip, the position of the semiconductor chip was displaced, and a step was observed on the surface on the semiconductor chip side (the surface on which the rewiring layer was formed) after the sealing step. Therefore, for example, it is considered that it is not suitable for use in a sealing step when manufacturing FOWLP and FOPLP.

DESCRIPTION OF SYMBOLS 10 Double-sided adhesive sheet 11 Base material 121 First adhesive layer 121a Adhesive surface 122 Second adhesive layer 122a Adhesive surface 131, 132 Release material 20 Hard support 30 Out of the adhesive surface of the first adhesive layer, around the semiconductor chip Part 40 sealing material 41 hardened sealing material 50 hardened sealing body 50a surface 61 first insulating layer 62 second insulating layer 70 rewiring 70A external electrode pad 80 external terminal electrode 100 semiconductor device CP semiconductor chip W1 circuit surface W2 circuit W3 Internal terminal electrode

Claims (11)

A method for manufacturing a semiconductor device using a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer, a non-tacky base material containing expandable particles, and a second pressure-sensitive adhesive layer in this order,
A method for manufacturing a semiconductor device, comprising the following steps (1) to (4).
Step (1): a step of attaching a hard support to the adhesive surface of the second adhesive layer Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the first adhesive layer Step (3) ): The semiconductor chip and the peripheral portion of the semiconductor chip on the adhesive surface of the first adhesive layer are covered with a sealing material, and the sealing material is cured to cure and seal the semiconductor chip. Step of obtaining a cured sealing body sealed with a material Step (4): a step of expanding the expandable particles and peeling the double-sided pressure-sensitive adhesive sheet from the cured sealing body The method for manufacturing a semiconductor device according to claim 1, further comprising the following step (5).
Step (5): a step of forming a rewiring layer on the cured sealing body from which the double-sided pressure-sensitive adhesive sheet has been peeled off   The expandable particles are heat-expandable particles, and in the step (4), the heat-expandable particles are expanded by heating the double-sided pressure-sensitive adhesive sheet, and the double-sided pressure-sensitive adhesive sheet is sealed with the cured sealing body. The method of manufacturing a semiconductor device according to claim 1, wherein the method is a step of separating the semiconductor device from the semiconductor device.   The method according to claim 3, wherein an expansion start temperature (t) of the thermally expandable particles is 120 to 250 ° C. 5. The method according to claim 4, wherein the base material satisfies the following requirements (1) and (2).
-Requirement (1): The storage elastic modulus E '(100) of the base material at 100 ° C is 2.0 × 10 ⁵ Pa or more.
-Requirement (2): The storage elastic modulus E '(t) of the base material at the expansion start temperature (t) of the thermally expandable particles is 1.0 × 10 ⁷ Pa or less.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the expandable particles have an average particle size before expansion at 23 ° C of 3 to 100 µm. The storage shear modulus G ′ (23) of the first pressure-sensitive adhesive layer at 23 ° C. is 1.0 × 10 ^{4 to} 1.0 × 10 ⁸ Pa, according to any one of claims 1 to 6. Of manufacturing a semiconductor device.   The ratio according to any one of claims 1 to 7, wherein the ratio of the thickness of the base material to the thickness of the first pressure-sensitive adhesive layer (base material / first pressure-sensitive adhesive layer) at 23 ° C is 0.2 or more. The manufacturing method of the semiconductor device described in the above.   The manufacturing of the semiconductor device according to any one of claims 1 to 8, wherein at 23 ° C, the thickness of the base material is 10 to 1000 µm, and the thickness of the first pressure-sensitive adhesive layer is 1 to 60 µm. Method.   The method for manufacturing a semiconductor device according to claim 1, wherein a probe tack value on a surface of the base material is less than 50 mN / 5 mmφ. It is a double-sided pressure-sensitive adhesive sheet used in the method for manufacturing a semiconductor device according to any one of claims 1 to 10, wherein the first pressure-sensitive adhesive layer, a base material containing expandable particles, and non-adhesive, And a second pressure-sensitive adhesive layer in this order.

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