WO2024225161A1

WO2024225161A1 - Film adhesive agent with dicing film, electronic component using same and manufacturing method therefor

Info

Publication number: WO2024225161A1
Application number: PCT/JP2024/015428
Authority: WO
Inventors: 小雪坂井
Original assignee: 古河電気工業株式会社
Priority date: 2023-04-28
Filing date: 2024-04-18
Publication date: 2024-10-31

Abstract

This film adhesive agent with a dicing film has: a dicing film having a base and an adhesive layer; and a film adhesive agent disposed on the adhesive layer. A storage elastic modulus E1 (MPa) of the film adhesive agent at 60°C and a storage elastic modulus E2 (MPa) of the dicing film at 60°C satisfy E1 × E2 ≥ 7.0, and the light transmittance of the cured product of the film adhesive agent is 60% or greater.

Description

Film-like adhesive with dicing film, electronic components using same, and manufacturing method thereof

The present invention relates to a film-like adhesive with a dicing film, electronic components using the same, and a method for manufacturing the same.

Photographing devices such as digital still cameras and digital video cameras incorporate image sensors (imaging elements) such as CMOS (Complementary Metal Oxide Semiconductor) image sensors and CCD (Charge Coupled Device) image sensors. In the image sensor, incident light is photoelectrically converted by a photodiode to convert it into an electrical signal, and a digital image is formed through signal processing. A color filter, a microlens, etc. are arranged on the surface of the photodiode as necessary, and a transparent protective film such as a glass plate is usually arranged on the surface. Such a transparent protective film is fixed via a film-like adhesive or the like. The adhesive used for bonding and fixing the transparent protective film of the image sensor is required to have transparency that allows sufficient light to pass through at least after a curing reaction.
Film-like adhesives themselves are known in various compositions and are widely used not only in image sensors but also in the manufacture of electronic devices and their components, etc. For example, in the manufacturing process of semiconductor chips, film-like adhesives are used as die attach films.

It has been proposed to use a film-like adhesive that exhibits sufficiently high transparency at least after a curing reaction as a laminated structure with a dicing film (film-like adhesive with a dicing film) for the manufacture of electronic components. For example, Patent Document 1 describes a method for manufacturing electronic components, which includes a first step of obtaining a laminate in which a transparent film-like member, a film-like adhesive that exhibits sufficiently high transparency after a curing reaction, and a dicing film are laminated in this order, a second step of obtaining a transparent film-like chip with an adhesive layer on the dicing film by dicing the transparent film-like member and the film-like adhesive together, a third step of removing the dicing film from the adhesive layer, and thermocompressing the transparent film-like chip with the adhesive layer and other members constituting the electronic component via the adhesive layer, and a fourth step of thermosetting the adhesive layer. Examples of the transparent film-like member include a glass substrate and a transparent resin, and the transparent film-like chip with an adhesive layer obtained by dicing the transparent film-like member into a desired shape as described above can be incorporated into an electronic component via the cured product of the adhesive layer, for example, as a protective film for a photodiode.
In addition, the above-mentioned film-like adhesive with dicing film can also be used as a dicing die attach film in the semiconductor chip manufacturing process, for dicing a semiconductor wafer and applying adhesive to the semiconductor chips separated by dicing.

International Publication No. 2023/026584

In the above-mentioned dicing process, a phenomenon (chip flying) in which the chips separated by dicing peel off from the film-like adhesive during dicing can occur to a considerable extent. After extensive research, the present inventors have found that when the amount of particulate additive such as a filler is reduced in order to increase the transparency of the film-like adhesive, chip flying during the dicing process becomes more likely to occur.
The present invention aims to provide a film-like adhesive with a dicing film, which exhibits sufficiently high transparency at least after a curing reaction and can effectively suppress chip flying during a dicing process. Another object of the present invention is to provide a method for manufacturing electronic components using this film-like adhesive with a dicing film.

The above object of the present invention is achieved by the following means.
[1]
A dicing film having a substrate and a pressure-sensitive adhesive layer, and a film-like adhesive disposed on the pressure-sensitive adhesive layer,
the storage modulus E1 (MPa) of the film-like adhesive at 60° C. and the storage modulus E2 (MPa) of the dicing film at 60° C. satisfy E1×E2≧7.0,
A film-like adhesive with a dicing film, wherein the light transmittance of the cured product of the film-like adhesive is 60% or more.
[2]
The film-like adhesive with a dicing film according to [1], wherein the film-like adhesive contains an epoxy resin and a phenoxy resin.
[3]
The film-like adhesive with a dicing film according to [1] or [2], wherein the film-like adhesive contains a filler and the content of the filler is 10 mass% or less of the total solid content of the film-like adhesive.
[4]
The film-like adhesive with a dicing film according to [3], wherein the average particle size (d50) of the filler is 500 nm or less.
[5]
The film-like adhesive with a dicing film according to any one of [1] to [4], wherein the film-like adhesive contains a curing agent, and the curing agent is a thermal cationic polymerization initiator.
[6]
The film-like adhesive with a dicing film according to any one of [1] to [5], wherein E1 is 0.1 to 1.0 MPa and E2 is 10 to 70 MPa.
[7]
A method for manufacturing an electronic component, comprising:
A first step of obtaining a laminate in which a transparent film-like member and a film-like adhesive with a dicing film according to any one of items [1] to [6] are laminated in this order;
a second step of dicing the transparent film-like member and the film-like adhesive together to obtain a transparent film-like chip with an adhesive layer on the dicing film;
a third step of removing the dicing film from the adhesive layer and thermocompression bonding the transparent film-like chip with the adhesive layer and other members constituting an electronic component via the adhesive layer;
a fourth step of thermally curing the adhesive layer;
A method for manufacturing an electronic component comprising the steps of:
[8]
The method for manufacturing an electronic component according to claim 7, wherein the electronic component is an image sensor.
[9]
The method for manufacturing an electronic component according to [8], wherein the electronic component has a structure in which the transparent film-like chip is incorporated as a protective film for a photodiode.

In the present invention, the numerical range expressed using "to" means a range including the numerical values before and after "to" as the lower and upper limits.
In the present invention, the term "compound having a skeleton" refers to a compound having a skeleton. For example, a "dicyandiamide compound" refers to not only dicyandiamide itself, but also a form in which at least a portion of the hydrogen atoms of dicyandiamide have been substituted.

The film-like adhesive with dicing film of the present invention exhibits sufficiently high transparency at least after the curing reaction, and can effectively suppress chip flying when applied to the dicing process. Furthermore, according to the manufacturing method of electronic components of the present invention, chip flying of the transparent film-like chip obtained in the dicing process can be effectively suppressed, and as a result, electronic components in which a transparent film-like chip is incorporated via a transparent cured product of the film-like adhesive can be obtained with high productivity.

FIG. 1 is a cross-sectional view showing a schematic structure of a film-like adhesive with a release film prepared in the Examples.

[Film-type adhesive with dicing film]
The film-like adhesive with dicing film of the present invention comprises a dicing film having a substrate and a pressure-sensitive adhesive layer, and a film-like adhesive disposed on the pressure-sensitive adhesive layer, wherein the storage modulus E1 (MPa) of the film-like adhesive at 60° C. and the storage modulus E2 (MPa) of the dicing film at 60° C. satisfy E1×E2≧7.0, and the light transmittance of the film-like adhesive after curing is 60% or more.
By satisfying the above relationship between the storage moduli E1 and E2, the rigidity of the entire film-like adhesive with the dicing film of the present invention is guaranteed even when the film-like adhesive with the dicing film of the present invention is locally heated by the frictional heat of the blade during dicing (it can be heated to about 60 ° C.), chip flying can be effectively suppressed, and since it shows high transparency after the curing reaction, it shows excellent optical properties as an adhesive when incorporating a transparent film-like member into an electronic component, etc. In order to control the integrated storage modulus of the dicing film and the film-like adhesive, even if a film-like adhesive layer with a relatively small storage modulus is used by reducing the amount of the fine particle additive, it is considered that the storage modulus of the dicing film as a whole can be appropriately controlled, and vibration during dicing can be suppressed.

In the present invention, the storage modulus E1 (MPa) of the film-like adhesive at 60°C and the storage modulus E2 (MPa) of the dicing film at 60°C are preferably E1 x E2 ≥ 10.0, more preferably E1 x E2 ≥ 11.0, even more preferably E1 x E2 ≥ 12.0, and particularly preferably E1 x E2 ≥ 15.0, from the viewpoint of suppressing chip flying. The upper limit is not particularly limited, and is usually 50.0 ≥ E1 x E2, with 40.0 ≥ E1 x E2 being practical. Therefore, 50.0 ≥ E1 x E2 ≥ 7.0 is preferred, 50.0 ≥ E1 x E2 ≥ 10.0 is more preferred, 50.0 ≥ E1 x E2 ≥ 11.0 is even more preferred, 50.0 ≥ E1 x E2 ≥ 12.0 is even more preferred, and 40.0 ≥ E1 x E2 ≥ 15.0 is particularly preferred.

The storage modulus E1 of the film-like adhesive at 60° C. is not particularly limited as long as the relationship between E1 and E2 is satisfied. E1 is preferably 0.1 to 1.5 MPa, more preferably 0.1 to 1.0 MPa, even more preferably 0.2 to 1.0 MPa, even more preferably 0.3 to 0.9 MPa, and even more preferably 0.3 to 0.8 MPa.
The storage modulus E2 of the dicing film at 60° C. is not particularly limited as long as it satisfies the relationship between E1 and E2. E2 is preferably 10 to 80 MPa, more preferably 10 to 70 MPa, even more preferably 20 to 70 MPa, even more preferably 25 to 60 MPa, and even more preferably 30 to 50 MPa.

The storage modulus E1 of the above-mentioned film-like adhesive at 60° C. can be controlled by the types and contents of the components (resin, curing agent, filler, etc.) that make up the film-like adhesive.
The storage modulus E2 of the dicing film at 60°C can be controlled by the type and content of the components (resins constituting the adhesive layer and the substrate) constituting the dicing film, the thickness of the adhesive layer and the substrate, etc. Since the substrate usually has a greater thickness than the adhesive layer, E2 tends to be greatly affected by the characteristics of the substrate. From this viewpoint, the storage modulus E3 of the substrate of the dicing film at 60°C is preferably 10 to 80 MPa, more preferably 10 to 70 MPa, even more preferably 20 to 70 MPa, even more preferably 30 to 60 MPa, and even more preferably 30 to 50 MPa.
The storage modulus E1 of the film-like adhesive at 60° C. and the storage modulus E2 of the dicing film at 60° C. can be determined by the method described in the Examples. The storage modulus E3 of the substrate at 60° C. can also be determined in accordance with the method for determining the storage modulus E2 of the dicing film at 60° C.

The film-like adhesive constituting the film-like adhesive with dicing film of the present invention has a light transmittance of 60% or more after curing. By having a transmittance of 60% or more after curing, transparency can be ensured after curing, and optical properties suitable for bonding transparent film-like members and the like can be exhibited. Here, in the present invention, "light transmittance of 60% or more" means that the light transmittance at a wavelength of 400 nm is 60% or more. The light transmittance at a wavelength of 400 nm represents the light transmittance at all wavelengths in the visible light range.
"Cured film adhesive" means a cured film adhesive cured by treating the film adhesive at 150°C for 1 hour. In the present invention and the specification, when the term "film adhesive" is used to describe the properties of the film adhesive, it means the film adhesive before thermal curing. Specifically, it means a film adhesive that has not been exposed to a temperature equal to or higher than the temperature at which the epoxy resin is thermally cured after preparation of the film adhesive. Preferably, the film adhesive has not been exposed to a temperature condition of 25°C or higher after preparation of the film adhesive. The above description is intended to clarify the properties of the film adhesive, and the film adhesive with dicing film of the present invention is not limited to a film adhesive that has not been exposed to a temperature condition of 25°C or higher.
The light transmittance of the cured product of the film-like adhesive is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. The light transmittance of the cured product of the film-like adhesive is preferably 70 to 95%, more preferably 80 to 92%, and even more preferably 85 to 90%.
The light transmittance of the cured film-like adhesive is determined by the method described in the Examples.
The light transmittance of the cured product of the film-like adhesive can be controlled by the type and content of the components of the film-like adhesive (resin, curing agent, filler, etc.). Not only the content but also the particle size of the filler can affect the light transmittance.
The transparency of the film-like adhesive before curing is not limited, and it may be transparent or opaque. Therefore, the light transmittance of the film-like adhesive before curing at a wavelength of 400 nm may be 60% or more, or may be less than 60%.

The film-like adhesive with dicing film of the present invention will be described in more detail below.

<Dicing film>
The dicing film constituting the film-like adhesive with dicing film of the present invention has a substrate and a pressure-sensitive adhesive layer.
There are no particular limitations on the materials and compositions of the substrate and pressure-sensitive adhesive layer as long as they satisfy the above E1 and E2 when laminated to form a dicing film and then combined with a film-like adhesive.

- Substrate -
The substrate can be made of various resin materials. Among them, those made of a resin material selected from polyolefin resin and polyvinyl chloride resin are preferable. It is also preferable that these resin materials have a crosslinked structure. The bond that contributes to the formation of the crosslinked structure may be a covalent bond, a bond based on ionic interaction, or a hydrogen bond.

The above polyolefin resins include polyethylene, polypropylene, ethylene-propylene copolymers, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid alkyl ester copolymers (ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-methyl methacrylate copolymers, etc.), ethylene-(meth)acrylic acid copolymers, ionomer resins, and other α-olefin homopolymer or copolymer resins, or mixtures of these.

In particular, ionomer resins, which are synthetic resins that utilize the cohesive force of metal ions to form polymer aggregates, are preferred, and examples thereof include ionomer resins in which an ethylene-(meth)acrylic acid binary copolymer or an ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester terpolymer is crosslinked with a metal ion. These are suitable for the expanding process in terms of uniform expandability. The metal ions contained in the ionomer resins are not particularly limited, but examples include zinc ions and sodium ions. Zinc ions are preferred in terms of low elution and low contamination.
In general, ionomer resins have a greater restoring force against tension than resins without metal ions, and experience a greater shrinkage stress when heat is applied to the stretched state after the expanding step. Therefore, ionomer resins are preferable in that they can be used in a heat shrink step in which the slack generated in the tape after the expanding step is removed by thermal shrinkage and the tape is tensioned to stably maintain the spacing between the individual wafer chips.

In addition to the above ionomer resins, thermoplastic crosslinked resins obtained by crosslinking a resin selected from low-density polyethylene having a specific gravity of 0.910 or more and less than 0.930, ultra-low-density polyethylene having a specific gravity of less than 0.910, and ethylene-vinyl acetate copolymer are also suitable.
As a method of crosslinking, a method of irradiating the resin with energy rays such as electron beams can be mentioned. Such a thermoplastic crosslinked resin has a certain degree of uniform extensibility because crosslinked and non-crosslinked sites coexist in the resin. In addition, such a thermoplastic crosslinked resin contains almost no chlorine atoms in the molecular chain structure, so that even if the tape that is no longer needed after use is incinerated, it does not generate chlorinated aromatic hydrocarbons such as dioxins and their analogues, and the environmental load is small. By appropriately adjusting the amount of energy rays irradiated to the polyethylene or ethylene-vinyl acetate copolymer, a resin having sufficient uniform extensibility can be obtained.

The substrate may be a single layer or a multi-layer substrate.
The substrate is preferably an ionomer resin of an ethylene-(meth)acrylic acid copolymer.

There are no particular limitations on the thickness of the substrate, but a thickness of 50 to 200 μm is preferred, 60 to 160 μm is more preferred, and 70 to 150 μm is even more preferred.

- Adhesive layer -
The adhesive layer constituting the adhesive tape of the present invention is not particularly limited, so long as it has the retention properties to prevent peeling between the laminate of the transparent film-like member (adherend) described below and the film-like adhesive during the dicing process, and the properties that enable peeling from the adhesive-attached transparent film-like chip when picked up.
The adhesive constituting the adhesive layer is not particularly limited as long as it exhibits the above-mentioned characteristics, and general adhesives used in dicing film applications, such as acrylic adhesives and rubber adhesives, can be used as appropriate. Among them, energy ray curable adhesives are preferred. If the energy ray curable adhesive is cured before the pick-up step, pick-up becomes easier. Here, the energy ray refers to light rays such as ultraviolet rays, or ionizing radiation such as electron beams.
The adhesive constituting the adhesive layer may be any ordinary adhesive used as an adhesive for dicing adhesive tapes without any particular limitations. For the components, characteristics, and manufacturing method of the adhesive, reference may be made to, for example, paragraphs [0039] to [0076] of Japanese Patent No. 6928852, paragraphs [0033] to [0052] of Japanese Patent No. 6989561, and paragraphs [0031] to [0057] of Japanese Patent Laid-Open No. 2023-13022.

The adhesive constituting the adhesive layer is preferably an acrylic adhesive containing a (meth)acrylic resin as a base polymer, and more preferably an acrylic adhesive containing at least one of a (meth)acrylic acid alkyl ester and (meth)acrylic acid as a constituent. The (meth)acrylic acid alkyl ester preferably further has a radiation-curable group introduced into the side chain, and more preferably has a (meth)acrylic acid ester having an isocyanate group added thereto. The adhesive may further contain a radiation-curable oligomer, for example, a urethane (meth)acrylate oligomer.

The pressure-sensitive adhesive layer may contain a curing agent. Examples of the curing agent include a polyisocyanate compound.
The pressure-sensitive adhesive layer may also contain a photopolymerization initiator.

There are no particular limitations on the thickness of the adhesive layer, but a thickness of 2 to 35 μm is preferred, 5 to 30 μm is more preferred, and 5 to 20 μm is even more preferred.

<Film-type adhesive>
The film-like adhesive constituting the film-like adhesive with dicing film of the present invention will be described.
Any conventional film-like adhesive can be used as long as it satisfies E1 and E2 above when combined with a dicing film and the cured product of the film-like adhesive has a light transmittance of 60% or more.
The film-like adhesive preferably contains an epoxy resin and a polymer component, more preferably contains an epoxy resin and a urethane resin or an epoxy resin and a phenoxy resin, and even more preferably contains an epoxy resin and a phenoxy resin.
The film-like adhesive may contain a filler. However, from the viewpoint of improving light transmittance, when the film-like adhesive contains a filler, the content of the filler is preferably 30 mass % or less of the total solid content of the film-like adhesive, more preferably 20 mass % or less, even more preferably 10 mass % or less, and even more preferably 5 mass % or less.
The film adhesive usually contains a curing agent.
In a preferred embodiment of the present invention, the film adhesive preferably contains an epoxy resin, a polymer component, and a curing agent. In this case, as described above, a filler may be contained. Each component will be described below.

-Epoxy resin-
The epoxy resin is a thermosetting resin having an epoxy group, and has an epoxy equivalent of 1000 g/eq or less. The epoxy resin may be liquid, solid, or semi-solid. In the present invention, the term "liquid" refers to a resin having a softening point of less than 25°C, the term "solid" refers to a resin having a softening point of 60°C or more, and the term "semi-solid" refers to a resin having a softening point between the softening points of the liquid and the solid (25°C or more and less than 60°C). The epoxy resin used in the present invention preferably has a softening point of 100°C or less, from the viewpoint of obtaining a film-like adhesive that can reach a low melt viscosity in a suitable temperature range (for example, 60 to 120°C). In the present invention, the softening point is a value measured by a softening point test (ring and ball method) method (measurement conditions: in accordance with JIS-K7234 1986).

In the epoxy resin used in the present invention, from the viewpoint of increasing the crosslink density of the thermoset, the epoxy equivalent is preferably 150 to 800 g/eq. In the present invention, the epoxy equivalent refers to the number of grams (g/eq) of a resin containing 1 gram equivalent of epoxy groups.
The weight average molecular weight of the epoxy resin is usually preferably less than 10,000, and more preferably not more than 5,000. There is no particular restriction on the lower limit, but a value of 300 or more is practical.
The weight average molecular weight is a value determined by GPC (Gel Permeation Chromatography) analysis.

Examples of the epoxy resin skeleton include phenol novolac type, orthocresol novolac type, cresol novolac type, dicyclopentadiene type, biphenyl type, fluorene bisphenol type, triazine type, naphthol type, naphthalene diol type, triphenylmethane type, tetraphenyl type, bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type, and trimethylolmethane type. Of these, triphenylmethane type, bisphenol A type, cresol novolac type, and orthocresol novolac type are preferred from the viewpoint of obtaining a film-like adhesive with low resin crystallinity and good appearance. These may be used alone or in combination of two or more types, and a combination of triphenylmethane type and bisphenol A type is preferred.

The content of the epoxy resin is preferably 25 to 80 parts by mass, more preferably 30 to 80 parts by mass, even more preferably 30 to 70 parts by mass, and even more preferably 40 to 70 parts by mass, per 100 parts by mass of the total content of the components constituting the film-like adhesive (specifically, the components other than the solvent, i.e., the solid content). By setting the content within the above preferred range, storage stability and transparency can be improved. Furthermore, by setting the content below the above preferred upper limit, the generation of oligomer components can be suppressed, and changes in the film state (film tackiness, etc.) due to slight temperature changes can be made less likely.
The content of the epoxy resin is preferably 30 to 70 parts by mass, and more preferably 30 to 60 parts by mass, per 100 parts by mass of the total content of the epoxy resin and the polymer component.

- Polymer components -
The polymer component may be any component that, when a film-like adhesive is formed, suppresses film tackiness (the property of film state being easily changed even by a slight change in temperature) at room temperature (25°C) and imparts sufficient adhesiveness and film-forming properties (film-forming properties). Examples of the polymer component include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as 6-nylon and 6,6-nylon, phenoxy resin, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyamideimide resin, fluororesin, polyurethane resin, etc. These polymer components may be used alone or in combination of two or more. As the polymer component, at least one of phenoxy resin and polyurethane resin is preferable.

The weight average molecular weight of the polymer component is at least 10,000. There is no particular upper limit, but a value of 5,000,000 or less is practical.
The weight average molecular weight of the polymer component is a value determined by GPC (gel permeation chromatography) in terms of polystyrene. Hereinafter, the weight average molecular weight of a specific polymer component has the same meaning.
The glass transition temperature (Tg) of the polymer component is preferably less than 100° C., and more preferably less than 90° C. The lower limit is preferably 0° C. or higher, and more preferably 10° C. or higher. Therefore, the glass transition temperature (Tg) of the polymer component is preferably 0° C. or higher and less than 100° C.
The glass transition temperature of the polymer component is a glass transition temperature measured by a differential scanning calorimeter (DSC) at a temperature increase rate of 0.1°C/min. More specifically, the temperature was increased from -100°C to 100°C at a temperature increase rate of 0.1°C/min, and the extrapolated glass transition onset temperature according to JIS K7121:2012 "Method for measuring transition temperature of plastics" was used as the glass transition temperature. Hereinafter, the glass transition temperature value of a specific polymer component has the same meaning.
In the present invention, among the epoxy resins and polymer components, resins that may have an epoxy group, such as phenoxy resins, are classified as follows: resins having an epoxy equivalent of 1000 g/eq or less are classified as epoxy resins, and resins having an epoxy equivalent of more than 1000 g/eq are classified as polymer components.

(Phenoxy resin)
Phenoxy resin is preferred as a polymer component because it has a similar structure to epoxy resin and is therefore compatible with epoxy resin. When phenoxy resin is contained, it can also exhibit excellent adhesive properties.
The phenoxy resin can be obtained by a conventional method, for example, by reacting a bisphenol or biphenol compound with an epihalohydrin such as epichlorohydrin, or by reacting a liquid epoxy resin with a bisphenol or biphenol compound.

The weight average molecular weight of the phenoxy resin is preferably 10,000 or more, and more preferably 10,000 to 100,000.
The amount of epoxy groups remaining in the phenoxy resin in small amounts is preferably 5,000 g/eq or more in terms of epoxy equivalent.

The glass transition temperature (Tg) of the phenoxy resin is preferably less than 100°C, and more preferably less than 90°C. The lower limit is preferably 0°C or higher, and more preferably 10°C or higher. Therefore, the glass transition temperature (Tg) of the phenoxy resin is preferably 0°C or higher and less than 100°C.

(Polyurethane resin)
The polyurethane resin is a polymer having a urethane (carbamic acid ester) bond in the main chain. The polyurethane resin has a structural unit derived from a polyol and a structural unit derived from a polyisocyanate, and may further have a structural unit derived from a polycarboxylic acid. The polyurethane resin may be used alone or in combination of two or more kinds.
The Tg of the polyurethane resin is usually 100° C. or less, preferably 60° C. or less, more preferably 50° C. or less, and also preferably 45° C. or less.

There are no particular restrictions on the weight-average molecular weight of the polyurethane resin, but those in the range of 5,000 to 500,000 are usually used.

Polyurethane resins can be synthesized by standard methods and are also available on the market. Commercially available products that can be used as polyurethane resins include Dynaleo VA-9320M, Dynaleo VA-9310MF, and Dynaleo VA-9303MF (all manufactured by Toyochem Co., Ltd.).

The content of the polymer component relative to 100 parts by mass of the epoxy resin is preferably 1 to 250 parts by mass, more preferably 10 to 180 parts by mass, and even more preferably 40 to 150 parts by mass. By setting the content within such a range, it is possible to adjust the rigidity and flexibility of the film-like adhesive before curing. The film condition becomes good (film tackiness is reduced), and film brittleness can also be suppressed.
The content of the polymer component is preferably 30 to 70 parts by mass, and more preferably 40 to 70 parts by mass, per 100 parts by mass of the total content of the epoxy resin and the polymer component.

- Hardener -
The curing agent is a component that affects the control of the light transmittance defined in the present invention. It is preferable to select the curing agent in consideration of the control of the light transmittance.

Examples of the curing agent include amines, acid anhydrides, and polyhydric phenols. From the viewpoint of storage stability of the film-like adhesive, it is preferable to use a latent curing agent. Examples of the latent curing agent include dicyandiamide compounds, imidazole compounds, curing catalyst composite polyhydric phenol compounds, hydrazide compounds, boron trifluoride-amine complexes, amine imide compounds, polyamine salts, and modified products and microcapsule-type products thereof, which may be used alone or in combination of two or more. Among them, it is preferable to use at least one of dicyandiamide compounds, imidazole compounds, and hydrazide compounds.
The latent curing agent may be a thermal cationic polymerization initiator, and more preferably a thermal cationic polymerization initiator having a sulfonium cation as the cationic component and SbF ₆ ^- or PF ₆ ^- as the anionic component.

The content of the curing agent per 100 parts by mass of the epoxy resin is preferably 0.5 to 50 parts by mass, more preferably 1 to 40 parts by mass, even more preferably 1 to 30 parts by mass, even more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, from the viewpoint of exhibiting a sufficient curing speed and ensuring transparency after curing.

-Filling material-
As the filler, any filler that can be normally used in a film-like adhesive can be used without any particular limitation, so long as the above-mentioned light transmittance can be achieved. The filler is preferably an inorganic filler.
Examples of inorganic fillers include ceramics such as silica, clay, gypsum, calcium carbonate, barium sulfate, alumina (aluminum oxide), beryllium oxide, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, and boron nitride; metals or alloys such as aluminum, copper, silver, gold, nickel, chromium, lead, tin, zinc, palladium, and solder; and carbons such as carbon nanotubes and graphene. Examples of inorganic fillers include various inorganic powders.
The filler is preferably silica.

The particle size (d50) of the filler is not particularly limited, but from the viewpoint of increasing light transmittance, it is preferably 500 nm or less. The particle size is preferably 1 to 500 nm, more preferably 10 to 500 nm, even more preferably 10 to 499 nm, even more preferably 10 to 450 nm, even more preferably 10 to 350 nm, even more preferably 10 to 200 nm, and even more preferably 10 to 100 nm. The particle size (d50) is the so-called median diameter, and refers to the particle size at which the particle size distribution is measured by a laser diffraction/scattering method, and the cumulative distribution is 50% when the total volume of the particles is 100%.

-Other ingredients-
In addition to the epoxy resin, the curing agent, the polymer component, and the filler, the film-like adhesive may further contain an ion trapping agent (ion capture agent), a curing catalyst, a viscosity modifier, an antioxidant, a flame retardant, a colorant, etc., within a range that does not impair the effects of the present invention. For example, it may contain other additives described in WO 2017/158994.
From the viewpoint of adhesive reliability, it is preferable that the film adhesive does not contain a colorant such as a dye or pigment, and it is also preferable that the film adhesive does not contain a filler.
The total content of the epoxy resin and polymer component contained in the film-like adhesive is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more.

-Thickness of film adhesive-
The thickness of the film-like adhesive is not particularly limited and can be appropriately set depending on the purpose. The thickness of the film-like adhesive can be, for example, 1 to 30 μm, preferably 1 to 25 μm, preferably 1 to 20 μm, preferably 2 to 20 μm, preferably 3 to 20 μm, and preferably 4 to 20 μm. The thickness of the film-like adhesive can be measured by a contact linear gauge method (desktop contact thickness measuring device).

<Production of film-like adhesive with dicing film>
The method for producing the film-like adhesive with a dicing film is not particularly limited as long as it can provide a structure in which a dicing film and a film-like adhesive are laminated together.
For example, a coating liquid containing an adhesive is applied onto a release-treated release liner, dried to form an adhesive layer, and then the adhesive layer and a substrate are laminated together to obtain a laminate in which the substrate, adhesive layer, and release liner are laminated in order. Separately, a film-like adhesive forming composition is applied onto a release film (synonymous with release liner, but for convenience, the expression is changed here), and dried to form a film-like adhesive on the release film. Next, the release liner is peeled off to expose the adhesive layer, and the dicing film and the film-like adhesive are bonded together to obtain a film-like adhesive with a dicing film in which the substrate, adhesive layer, film-like adhesive, and release film are laminated in order.
The above-mentioned dicing film and die attach film are preferably bonded together under pressure.
In the above-mentioned lamination of the dicing film and the film-like adhesive, the shape of the dicing film is not particularly limited as long as it can cover the opening of the ring frame, and is preferably circular. The shape of the film-like adhesive is also not particularly limited as long as it can cover the back surface of the wafer, and is preferably circular. The dicing film is preferably larger than the film-like adhesive, and has a shape having a portion where the pressure-sensitive adhesive layer is exposed around the adhesive layer. In this way, it is preferable to laminate the dicing film and the film-like adhesive cut into the desired shape.
When the film-like adhesive with a dicing film produced as described above is used, the release film is peeled off.

The formation of the film-like adhesive will now be described in further detail.
The film-like adhesive can be obtained by forming a film using a composition (film-like adhesive-forming composition (varnish)) in which each component constituting the film-like adhesive is mixed at a temperature at which the epoxy resin does not actually cure by heat. The order of mixing is not particularly limited. For example, resin components such as epoxy resin and polymer component may be mixed together with a solvent as necessary, and then a curing agent may be mixed. In this case, mixing in the presence of the curing agent may be performed at a temperature at which the epoxy resin does not actually cure by heat, and mixing of the resin components in the absence of the curing agent may be performed at a higher temperature.
A film can be formed using the above-mentioned film-like adhesive-forming composition, for example, by applying the film-like adhesive-forming composition onto a release-treated substrate (also called a release film or peeling film) and drying it as necessary.
The release film may be any film that functions as a cover film for the resulting film-like adhesive, and any conventional film may be appropriately used. Examples of the release film include release-treated polypropylene (PP), release-treated polyethylene (PE), and release-treated polyethylene terephthalate (PET).
As the coating method, a conventional method can be appropriately adopted, and examples thereof include methods using a roll knife coater, a gravure coater, a die coater, and a reverse coater.
Drying may be performed by removing the organic solvent from the film-like adhesive-forming composition without substantially curing the epoxy resin to obtain a film-like adhesive, and may be performed, for example, by maintaining the composition at a temperature of 80 to 150°C for 1 to 20 minutes.

The film-like adhesive can be in a form in which the above-mentioned release film or the like is laminated to at least one surface. In this case, the release film does not constitute the film-like adhesive, but is considered to be laminated to the film-like adhesive. In other words, when describing the thickness of a film-like adhesive in a form in which the above-mentioned release film or the like is laminated to at least one surface of the film-like adhesive, the thickness does not include the thickness of the release film or the like. In other words, the thickness of the film-like adhesive in this invention is the thickness of the layer derived from the film-like adhesive-forming composition.

In order to more reliably suppress the thermal curing of the epoxy resin, it is preferable to store the film adhesive at a temperature of 10°C or less before use.

The film-like adhesive with a dicing film of the present invention may further be laminated with a release film or the like.
By forming the film-like adhesive with dicing film of the present invention into such a laminated film, a transparent film-like member (adherend) such as a transparent protective film is adhered to the film-like adhesive side of the laminated film, and the transparent film-like member is fixed via a dicing film, and the transparent film-like member can be cut (diced) to a desired size together with the film-like adhesive. As a result, a transparent film-like chip with an adhesive layer cut to a desired size can be obtained on the dicing film. Next, the transparent film-like chip with the adhesive layer is peeled off from the dicing film, and the transparent film-like chip can be incorporated into an electronic component via the adhesive layer. This incorporation into the electronic component is performed by thermocompression bonding or the like, and then the adhesive layer is thermally cured, and the transparency of the adhesive can be increased by, for example, reacting with a solid curing agent in association with the curing reaction.
The thermocompression bonding is carried out at a temperature at which the epoxy resin is not substantially cured, for example at about 70° C. and a pressure of about 0.3 MPa.
The above-mentioned heat curing reaction may be carried out at a temperature equal to or higher than the heat curing initiation temperature of the film-like adhesive. The heat curing initiation temperature varies depending on the type of epoxy resin, polymer component, and epoxy curing agent used, and cannot be generally stated, but for example, 100 to 180°C is preferable, and from the viewpoint of realizing curing in a short time, 140 to 180°C is more preferable. If the temperature is lower than the heat curing initiation temperature, the heat curing reaction does not proceed sufficiently, and the strength of the adhesive layer tends to decrease. On the other hand, if the temperature of the curing reaction is too high, the curing agent and additives in the film-like adhesive tend to volatilize during the curing reaction and foam easily. In addition, the time of the curing treatment is preferably, for example, 10 to 120 minutes.
In relation to the above-described embodiment, the present invention provides the following method for manufacturing an electronic component.

A method for manufacturing an electronic component, comprising:
A first step of obtaining a laminate in which a transparent film-like member and a film-like adhesive with a dicing film of the present invention are laminated in this order;
a second step of dicing the transparent film-like member and the film-like adhesive together to obtain a transparent film-like chip with an adhesive layer on the dicing film;
a third step of removing the dicing film from the adhesive layer and thermocompression bonding the transparent film-like chip with the adhesive layer and other members constituting an electronic component via the adhesive layer;
a fourth step of thermally curing the adhesive layer;
A method for manufacturing an electronic component comprising the steps of:

The electronic component obtained by the above-mentioned manufacturing method has a structure in which a transparent film-like chip is incorporated in the electronic component via a thermoset of the film-like adhesive.
In the present invention, the term "transparent film chip" refers to a transparent film processed into a desired shape. Typically, a transparent film member such as a glass substrate or transparent resin is cut into a desired shape for incorporation into an electronic component.

An example of the electronic component is an image sensor (imaging element). In this case, the transparent film-like chip incorporated in the electronic component is preferably a protective film for a photodiode.

The above describes a preferred embodiment of the transparent film-like member, and the present invention is not limited to these embodiments except as specified in the present invention. For example, preferred examples of the electronic components include optical lenses, optical fibers, optical waveguides, optical isolators, and members used in optical devices such as semiconductor lasers.

The present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following embodiments.
In the following description, room temperature means 25° C. Additionally, “MEK” is methyl ethyl ketone, and “PET” is polyethylene terephthalate.

For each example and comparative example, a film-like adhesive with a release film as shown in Figure 1 was prepared.

[Preparation of dicing film]
<Preparation of substrate>
(Substrate X)
A zinc ionomer resin of ethylene-methacrylic acid copolymer (product name: Himilan 1855, manufactured by DuPont-Mitsui Chemical Co., Ltd.) was melted at 200° C. and used in an extruder to prepare a substrate X having a thickness of 90 μm. One side of the substrate X was subjected to a corona treatment.
(Substrate Y)
A zinc ionomer resin of ethylene-methacrylic acid copolymer (product name: Himilan AM7326, manufactured by DuPont-Mitsui Chemical Co., Ltd.) was melted at 200° C. and used in an extruder to prepare a substrate Y having a thickness of 90 μm. One side of the substrate Y was subjected to a corona treatment.
(Substrate Z)
An ethylene-methacrylic acid copolymer (product name: Nucrel N0200H, manufactured by DuPont-Mitsui Chemical Co., Ltd.) was melted at 200° C. and used in an extruder to prepare a substrate Z having a thickness of 90 μm. One side of the substrate Z was subjected to a corona treatment.

<Dicing film A>
65 parts by mass of butyl acrylate, 25 parts by mass of 2-hydroxyethyl acrylate, and 10 parts by mass of acrylic acid were radically polymerized, and further reacted while adding 2-isocyanatoethyl methacrylate dropwise to obtain an acrylic copolymer having a weight average molecular weight of 800,000. 3 parts by mass of polyisocyanate as a curing agent and 1 part by mass of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator were added to 100 parts by mass of this acrylic copolymer and mixed to obtain a pressure-sensitive adhesive layer composition.
Next, the pressure-sensitive adhesive layer composition was applied to a release-treated release liner so as to give a dry film thickness of 10 μm, and dried for 3 minutes at 120° C. to obtain a pressure-sensitive adhesive layer. This pressure-sensitive adhesive layer was attached to the corona-treated surface of substrate X to produce dicing film A having a substrate and a pressure-sensitive adhesive layer with a release liner.

<Dicing film B>
Dicing film B was produced in the same manner as dicing film A, except that the substrate used was changed to substrate Y.

<Dicing film C>
Dicing film C was produced in the same manner as dicing film A, except that the substrate Z was used instead.

[Preparation of film-like adhesive with dicing film]
The components used in preparing the film adhesive are shown below.
<Materials used>
(Epoxy resin)
828 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 190 g/eq, specific gravity 1.17)
・ST-3000 (hydrogenated bisphenol A epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd.)
YDCN-703 (cresol novolac type epoxy resin, manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 210 g/eq, molecular weight 1200, softening point 80° C.)
(Phenoxy resin)
1256 (phenoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 7500 g/eq)
(urethane resin)
Dynaleo VA-9320M (urethane resin solution, weight average molecular weight: 120,000, Tg: 39°C, room temperature elastic modulus: 594 MPa, solvent: MEK/IPA mixed solvent, manufactured by Toyochem Co., Ltd.) (referred to as VA-9320M in the table)
(Acrylic resin)
SG-P3 (acrylic resin, Nagase ChemteX Corporation, weight average molecular weight 850,000, glass transition temperature 10°C)
(Hardening agent)
・2PHZ-PW (imidazole-based hardener, manufactured by Shikoku Kasei Co., Ltd.)
SI-150 (thermal cationic polymerization initiator, manufactured by Sanshin Chemical Industry Co., Ltd.)
(Phenol resin)
Milex XLC-LL (phenolic resin, manufactured by Mitsui Chemicals, Inc., hydroxyl equivalent: 175 g/eq)
(Filling material)
RY-200 (nanosilica filler, manufactured by Nippon Aerosil Co., Ltd., particle size (d50): 12 nm, Mohs hardness: 7 Mohs, thermal conductivity: 1 W/mK)
S0-C2 (silica filler, manufactured by ADMAFINE Co., Ltd., specific gravity 2.2 g/cm ³ , Mohs hardness: 7 Mohs, particle size (d50) 500 nm, specific surface area 6.0 m ² /g)

Example 1
(Preparation of film-like adhesive)
50 parts by mass of epoxy resin (product name: 828, manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent 190 g/eq, specific gravity 1.17) and 50 parts by mass of phenoxy resin (product name: 1256, manufactured by Mitsubishi Chemical Corporation, bisphenol A type phenoxy resin, epoxy equivalent 7500 g/eq) were heated and stirred with MEK in a 1000 ml separable flask at a temperature of 110° C. for 2 hours to obtain a resin varnish. Next, this resin varnish was transferred to another flask container, and 1 part by mass of a curing agent (product name: 2PHZ-PW, imidazole type curing agent, manufactured by Shikoku Kasei Co., Ltd.) was added, and the mixture was stirred and mixed at room temperature for 1 hour, and then vacuum degassed to obtain a mixed varnish. The resulting mixed varnish was then applied onto a 38 μm-thick release-treated PET film (release film) and dried by heating at 130° C. for 10 minutes to form a film-like adhesive layer with a length of 300 mm, a width of 300 mm, and a thickness of 20 μm. The resulting film-like adhesive with release film was stored at 10° C. or lower. After the drying, the epoxy resin was not cured (the same applies to other examples and comparative examples unless otherwise specified below).
(Preparation of film-like adhesive with dicing film)
Next, the dicing film B with the release liner was cut into a circular shape that could be attached to cover the opening of the ring frame. Also, the film-like adhesive with the release film was cut into a circular shape that could cover the back surface of the wafer.
The dicing film B cut as described above with the release liner was peeled off to expose the dicing film B, and the film-like adhesive with the release film cut as described above was laminated together using a roll press under conditions of a load of 0.4 MPa and a speed of 1.0 m/min to produce a film-like adhesive with a dicing film in which a substrate, a pressure-sensitive adhesive layer, a film-like adhesive, and a release film are laminated in this order. In this film-like adhesive with a dicing film, the film-like adhesive is formed on the pressure-sensitive adhesive layer of the dicing film having a substrate and a pressure-sensitive adhesive layer. In addition, in this film-like adhesive with a dicing film, the dicing film is larger than the film-like adhesive, and the dicing film has an exposed portion around the film-like adhesive.

Example 2
In preparing the film-like adhesive of Example 1, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 1, except that 1 part by mass of SI-150 was used instead of 2PHZ-PW as the curing agent, and 3 parts by mass of RY-200 was added to the mixed varnish as a filler.

Example 3
A film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 1, except that in preparing the film-like adhesive of Example 1, 11 parts by mass of RY-200 was added to the mixed varnish as a filler.

Example 4
In preparing the film-like adhesive of Example 2, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 2, except that 5 parts by mass of S0-C2 was added to the mixed varnish instead of RY-200 as a filler.

Example 5
In producing the film-like adhesive with a dicing film of Example 2, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 2, except that dicing film A was used as the dicing film.

Example 6
In producing the film-like adhesive with a dicing film of Example 3, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 3, except that dicing film A was used as the dicing film.

Example 7
In producing the film-like adhesive with a dicing film of Example 4, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 4, except that dicing film A was used as the dicing film.

Example 8
A film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 5, except that in preparing the film-like adhesive of Example 5, 150 parts by mass of a urethane resin solution (VA-9320M) (including 50 parts by mass of urethane resin) was used instead of the phenoxy resin (1256) as the polymer component, the curing agent in the mixed varnish was 1 part by mass of 2PHZ-PW, and 35 parts by mass of RY-200 was added as a filler.

<Example 9>
In preparing the film-like adhesive of Example 5, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 5, except that 50 parts by mass of ST-3000 was used instead of 828 as the epoxy resin.

Example 10
In preparing the film-like adhesive of Example 5, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 5, except that 20 parts by mass of RY-200 was added to the mixed varnish as a filler.

Example 11
In preparing the film-like adhesive of Example 5, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 5, except that the amount of 828 in the resin varnish was 30 parts by mass and the amount of 1256 was 70 parts by mass.

Example 12
In preparing the film-like adhesive of Example 2, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 2, except that the amount of 828 in the resin varnish was 60 parts by mass and the amount of 1256 was 40 parts by mass.

<Comparative Example 1>
In producing the film-like adhesive with a dicing film of Example 1, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 1, except that dicing film A was used as the dicing film.

<Comparative Example 2>
In preparing the film-like adhesive of Comparative Example 1, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Comparative Example 1, except that 80 parts by mass of S0-C2 was added to the mixed varnish as a filler.

<Comparative Example 3>
In preparing the film-like adhesive of Example 1, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 1, except that 18 parts by mass of YDCN-703 was used instead of 828 as the epoxy resin, 100 parts by mass of acrylic resin (SG-P3) was used instead of phenoxy resin (1256) as the polymer component, and 1 part by mass of 2PHZ-PW and 15 parts by mass of Milex XLC-LL were used as the curing agent.

<Comparative Example 4>
In preparing the film-like adhesive of Comparative Example 3, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Comparative Example 3, except that the amount of YDCN-703 blended was 50 parts by mass, the amount of SG-P3 blended was 250 parts by mass, 50 parts by mass of Milex XLC-LL was used as the curing agent without blending 2PHZ-PW, and 35 parts by mass of S0-C2 was added to the mixed varnish as a filler.

<Comparative Example 5>
In producing the film-like adhesive with a dicing film of Example 2, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 2, except that dicing film C was used as the dicing film.

<Comparative Example 6>
In producing the film-like adhesive with a dicing film of Example 3, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 3, except that dicing film C was used as the dicing film.

<Comparative Example 7>
In producing the film-like adhesive with a dicing film of Example 4, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 4, except that dicing film C was used as the dicing film.

<Comparative Example 8>
In preparing the film-like adhesive with a dicing film of Example 8, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 8, except that dicing film C was used as the dicing film.

<Comparative Example 9>
In preparing the film-like adhesive with a dicing film of Example 9, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 9, except that dicing film C was used as the dicing film.

<Comparative Example 10>
In preparing the film-like adhesive with a dicing film of Example 10, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 10, except that dicing film C was used as the dicing film.

<Comparative Example 11>
In preparing the film-like adhesive with a dicing film of Example 11, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 11, except that dicing film C was used as the dicing film.

<Comparative Example 12>
In preparing the film-like adhesive with a dicing film of Example 12, a film-like adhesive with a release film and a film-like adhesive with a dicing film were obtained in the same manner as in Example 12, except that dicing film C was used as the dicing film.

For the film-like adhesive with release film and dicing films A to C obtained in each of the above examples and comparative examples, the storage modulus of the film-like adhesive at 60°C and the storage modulus of the dicing film at 60°C were determined as follows.

[Measurement of storage modulus of film-like adhesive]
The release film was peeled off from the film-like adhesive with release film obtained in each Example and Comparative Example, and the film-like adhesive was laminated to a thickness of 0.5 mm at 70 ° C. using a laminator. This laminate was cut into a width of 5 mm to be used as a measurement sample. Using a dynamic viscoelasticity measuring device RSAIII (manufactured by TA Instruments), the viscoelastic behavior of the film-like adhesive was measured when it was heated from 25 ° C. to 80 ° C. at a heating rate of 5 ° C. / min under tensile conditions of a chuck distance of 20 mm and a frequency of 10 Hz, and the storage modulus E1 at 60 ° C. was calculated.

[Measurement of storage modulus of dicing film]
Each of the dicing films A to C was cut into a width of 5 mm to prepare a measurement sample. Using a dynamic viscoelasticity measuring device RSAIII (manufactured by TA Instruments), the viscoelastic behavior of the dicing film was measured when the temperature was increased from 25° C. to 80° C. at a heating rate of 5° C./min under tension conditions of a chuck distance of 20 mm and a frequency of 10 Hz, and the storage modulus E2 at 60° C. was calculated.
When the storage modulus of the substrate alone was measured at 60° C., it was found to be approximately the same as that of the dicing film.

The film-like adhesive with dicing film obtained in each of the above examples and comparative examples was evaluated for light transmittance and chipping after the film-like adhesive had hardened as follows.

[Measurement of light transmittance of cured film adhesive]
The film-like adhesive with the dicing film was heated and cured at 150°C for 1 hour, and then the dicing film was peeled off. The parallel ray transmittance of the film-like adhesive alone was measured using a spectrophotometer (Hitachi High-Technologies Corporation, Spectrophotometer U-4100 Solid Sample Measurement System) in the wavelength range of 200 to 1100 nm, and evaluated using the parallel ray transmittance at a wavelength of 400 nm.

[Chip flying evaluation]
The film-like adhesive with dicing film obtained in each Example and Comparative Example was first bonded to one side of a glass wafer (material D263, 10 cm square, thickness 100 μm) using a manual laminator (product name: FM-114, manufactured by Technovision) at a temperature of 70° C. and a pressure of 0.3 MPa so that the film-like adhesive layer was in contact with the surface. Then, using the same manual laminator, a dicing frame (product name: DTF2-8-1H001, manufactured by DISCO) was bonded to the area of the film-like adhesive to which the glass wafer was not bonded at room temperature and a pressure of 0.3 MPa. Next, dicing was performed from the glass wafer side to a size of 2 mm x 2 mm using a dicing machine (product name: DFD-6340, manufactured by DISCO) equipped with a two-axis dicing blade (Z1: NBC-ZH2050 (27HEDD), manufactured by DISCO; Z2: NBC-ZH127F-SE (BC), manufactured by DISCO). This dicing yielded 2500 chips. In the samples after dicing, the number of chips that had chipped (peeled off) was counted, and the chipping occurrence rate relative to the total number of chips (number of chips that had chipped/total number of chips x 100) was calculated. The obtained chipping occurrence rate was evaluated according to the following evaluation criteria.

-Evaluation criteria-
AA: Chip flying rate is 0%
A: The chip skipping rate is less than 1% of all chips. B: The chip skipping rate is 1% or more and less than 3% of all chips. C: The chip skipping rate is 3% or more of all chips.

The above results are summarized in the table below. In the table below, the values indicating the amounts of epoxy resin, polymer component, hardener, and filler are in parts by mass. A blank space indicates that the component is not contained. The "Filler content" column indicates the amount of filler contained in the total solid content of the film adhesive.

The film-like adhesive with a dicing film of Comparative Example 1 does not satisfy the storage modulus relationship E1×E2≧7.0 In the film-like adhesive with a dicing film of Comparative Example 1, chip flying occurred during dicing.
The film-like adhesive with dicing film of Comparative Examples 2 to 4 had a light transmittance of 35% or less for the cured product of the film-like adhesive, and did not exhibit sufficient transparency. One of the reasons for this is thought to be that the amount of filler in Comparative Example 2 was too large, and that in Comparative Examples 3 and 4, the acrylic resin was not compatible with the epoxy resin.
The film-like adhesives with dicing films of Comparative Examples 5 to 12 did not satisfy the storage modulus relationship E1×E2≧7.0 The film-like adhesives with dicing films of Comparative Examples 5 to 12 caused chip flying during dicing.
In contrast, the film-like adhesives with dicing films of Examples 1 to 12, which satisfied the provisions of the present invention, satisfied E1×E2≧7.0 and had a light transmittance of 60% or more after the curing of the film-like adhesive. It can be seen that the use of these film-like adhesives with dicing films makes it possible to effectively prevent chip flying during the dicing process, and also shows sufficiently high transparency after the curing reaction.

Although the present invention has been described in conjunction with its embodiments, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the appended claims should be interpreted broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

This application claims priority to Japanese Patent Application No. 2023-074875, filed on April 28, 2023, the contents of which are incorporated herein by reference as part of the present specification.

10 Dicing film 11 Substrate 12 Adhesive layer 20 Film-like adhesive

Claims

A dicing film having a substrate and a pressure-sensitive adhesive layer, and a film-like adhesive disposed on the pressure-sensitive adhesive layer,
the storage modulus E1 (MPa) of the film-like adhesive at 60° C. and the storage modulus E2 (MPa) of the dicing film at 60° C. satisfy E1×E2≧7.0,
A film-like adhesive with a dicing film, wherein the light transmittance of the cured product of the film-like adhesive is 60% or more.
The film-like adhesive with dicing film according to claim 1, wherein the film-like adhesive contains an epoxy resin and a phenoxy resin.
The film-like adhesive with dicing film according to claim 1 or 2, wherein the film-like adhesive contains a filler, and the content of the filler is 10 mass % or less of the total solid content of the film-like adhesive.
The film-like adhesive with dicing film according to claim 3, wherein the particle size (d50) of the filler is 500 nm or less.
The film-like adhesive with dicing film according to any one of claims 1 to 4, wherein the film-like adhesive contains a curing agent, and the curing agent is a thermal cationic polymerization initiator.
The film-like adhesive with dicing film according to any one of claims 1 to 5, wherein E1 is 0.1 to 1.0 MPa and E2 is 10 to 70 MPa.
A method for manufacturing an electronic component, comprising:
A first step of obtaining a laminate in which a transparent film-like member and the film-like adhesive with a dicing film according to any one of claims 1 to 6 are laminated in this order;
a second step of dicing the transparent film-like member and the film-like adhesive together to obtain a transparent film-like chip with an adhesive layer on the dicing film;
a third step of removing the dicing film from the adhesive layer and thermocompression bonding the transparent film-like chip with the adhesive layer and other members constituting an electronic component via the adhesive layer;
a fourth step of thermally curing the adhesive layer;
A method for manufacturing an electronic component comprising the steps of:
The method for manufacturing an electronic component according to claim 7, wherein the electronic component is an image sensor.
The method for manufacturing an electronic component according to claim 8, wherein the electronic component has a structure in which the transparent film-like chip is incorporated as a protective film for a photodiode.