TWI705116B - Composite sheet for forming protective film and method for producing the same - Google Patents

Abstract

The present invention provides a composite sheet for forming a protective film, including: a base material, an adhesive layer, and a protective film-forming film, wherein the adhesive layer is provided on the base material, and the protective film -forming film is provided on the adhesive layer; the adhesive sheet includes a (meth)acrylic acid alkyl ester copolymer at least in a layer which is in contact with the protective film-forming film, wherein the (meth)acrylic acid alkyl ester copolymer includes a structural unit derived from (meth)acrylic acid alkyl ester having 8 or more carbon atoms of an alkyl group which forms alkyl ester; and the composite sheet for forming the protective film is a sheet for use in manufacturing a semiconductor chip having a productive film, the manufacturing method including adhering the composite sheet for forming the protective film by the protective film-forming film on the back surface of a semiconductor wafer, forming the protective film by heat-curing the protective film-forming film, making the semiconductor chip by dicing the semiconductor wafer on which the protective film is formed, and after curing the adhesive layer by irradiating with an active energy ray, picking up the semiconductor chip together with the protective film which is adhered to the back surface thereof.

Description

Composite sheet for forming protective film and manufacturing method thereof

The present invention relates to a composite sheet for forming a protective film for forming a protective film on the back surface of a semiconductor wafer.

This application claims priority based on Japanese Patent Application No. 2015-114714 filed in Japan on June 5, 2015, and the content is cited herein.

In recent years, the industry has used a mounting method called a so-called face down method to manufacture semiconductor devices. In the flip-chip method, a semiconductor wafer having electrodes such as bumps on the circuit surface is used to join the electrodes to the substrate. Therefore, there are cases where the back surface of the chip opposite to the circuit surface is exposed.

Sometimes a resin film made of an organic material is formed as a protective film on the backside of the bare chip, which is formed into a semiconductor chip with a protective film and then assembled into a semiconductor device. The purpose of using the protective film is to prevent the chip from cracking after the dicing step or packaging, or to use Then, the obtained wafer is attached to the die pad portion or other semiconductor wafers and other components.

On the other hand, such a protective film is formed using a composite sheet for forming a protective film as described below. That is, the composite sheet for forming a protective film is provided with an adhesive layer on a base material and provided on the adhesive layer Film for forming protective film. Among the aforementioned composite sheets for forming a protective film, the film for forming a protective film has the function of forming a protective film, and the laminated structure of the substrate and the adhesive layer functions as a dicing sheet, which can be called a film for forming a protective film A composite sheet for forming a protective film integrated with the dicing sheet.

Such a composite sheet for forming a protective film is used as follows, for example. That is, after the composite sheet for protective film formation is attached to the back surface of the semiconductor wafer (the surface opposite to the electrode formation surface) through the protective film formation film, the semiconductor wafer is cut into semiconductor wafers. Then, the active energy rays are irradiated to harden the adhesive layer, the semiconductor wafer is peeled from the adhesive layer, and the semiconductor wafer is picked up. On the other hand, the protective film forming film is picked up together with the semiconductor wafer, and finally exists as a cured protective film on the back surface of the semiconductor wafer. As such a composite sheet for forming a protective film, there is disclosed a composite sheet for forming a protective film that is used in the following manner: when picking up a semiconductor wafer, the protective film forming film is brought into an uncured or partially cured state to bond the semiconductor wafer When the sealing material is cured (bonding), the uncured or partially cured protective film forming film is simultaneously made into a completely or substantially completely cured state (see Patent Document 1).

[Prior Technical Literature]

[Patent Literature]

Patent Document 1: JP 2011-228450 A.

However, the conventional composite sheet for forming a protective film as disclosed in Patent Document 1 has the following problem: under certain usage conditions, especially after the adhesive layer is hardened, the adhesive layer and the protective film forming film peel off If the force is too large, cracks or nicks are generated when picking up semiconductor wafers.

The present invention is made in view of the above circumstances. The subject of the present invention is to provide a composite sheet for forming a protective film for forming a protective film on the back of a semiconductor wafer, and having an adhesive layer on the substrate, on the adhesive layer Equipped with the protective film formation film, the peeling force of the adhesive layer and the protective film formation film or the protective film after the protective film formation film is cured is large enough before the adhesive layer is cured, and it can be cut stably. After the agent layer is hardened, it is small enough to pick up semiconductor wafers stably.

In order to solve the above-mentioned problems, the present invention provides a composite sheet for forming a protective film, which is provided with an adhesive layer on a substrate, a protective film forming film is provided on the adhesive layer, and the adhesive layer has active energy ray curability. The protective film forming film has thermosetting properties; the protective film forming composite sheet is used to manufacture a semiconductor wafer with a protective film, and the protective film forming composite sheet is attached to the semiconductor wafer through the protective film forming film. After the back of the circle is formed, the protective film forming film is cured by heating to form a protective film, then the semiconductor wafer is cut to form a semiconductor wafer, the adhesive layer is cured by irradiating active energy rays, and then the The semiconductor chip is picked up together with the protective film attached to the back surface of the semiconductor chip, thereby manufacturing the semiconductor chip with the protective film; the adhesive layer contains (methyl) in at least the layer in contact with the protective film forming film ) Alkyl acrylate copolymer, the aforementioned alkyl (meth)acrylate copolymer has a structural unit derived from an alkyl (meth)acrylate having an alkyl group of 8 or more carbon atoms.

In the composite sheet for forming a protective film of the present invention, it is preferable that the film for forming a protective film contains an epoxy resin, a thermosetting agent and imidazoles, and the thermosetting agent is dissolved by heating and exhibits curing activity on the epoxy resin.

The composite sheet for forming a protective film of the present invention preferably has 11 to 18 carbon atoms in the alkyl group constituting the alkyl ester.

That is, the present invention includes the following aspects.

[1] A composite sheet for forming a protective film, comprising an adhesive layer on a substrate, a protective film forming film on the adhesive layer, the adhesive layer having active energy ray curability, and the protective film forming The film has thermosetting properties; the composite sheet for forming a protective film is used to manufacture semiconductor wafers with a protective film, and the protective film is formed by the film for forming a protective film. After the composite sheet is attached to the back surface of the semiconductor wafer, the protective film forming film is hardened by heating to form a protective film, then the semiconductor wafer is cut to form a semiconductor chip, and then the adhesive is irradiated with active energy rays The agent layer is cured, and then the semiconductor chip is picked up together with the protective film attached to the back surface of the semiconductor chip, thereby manufacturing a semiconductor chip with a protective film; the adhesive layer is in contact with at least the protective film forming film The layer contains an alkyl (meth)acrylate copolymer; the aforementioned alkyl (meth)acrylate copolymer has an alkyl (meth)acrylate with a carbon number of 8 or more that constitutes the alkyl group of the alkyl ester Derived structural unit.

[2] The composite sheet for forming a protective film as described in [1], wherein the film for forming a protective film contains an epoxy resin, a thermosetting agent, and imidazoles, and the thermosetting agent is dissolved by heating and reacts to the ring Oxygen resin shows hardening activity.

[3] The composite sheet for forming a protective film as described in [1] or [2], wherein the number of carbon atoms in the alkyl group constituting the alkyl ester is 11 to 18.

According to the present invention, there is provided a composite sheet for forming a protective film, for forming a protective film on the back of a semiconductor wafer, and having an adhesive layer on a substrate, a protective film forming film on the adhesive layer, and the adhesive The peeling force between the layer and the protective film forming film or the protective film after the protective film forming film is cured (ie, the protective film as the cured product of the protective film forming film) is sufficient before the adhesive layer is cured Large enough for stable dicing, and small enough after the adhesive layer is hardened to pick up the semiconductor wafer stably.

1, 2, 3, 4: Composite sheet for forming protective film

10: Support film

11: Substrate

11a: The surface of the substrate

12, 32, 42: Adhesive layer

12a, 32a, 42a: the surface of the adhesive layer

120a: Area on the side of the protective film formation film

13, 23: Film for forming protective film

13a, 23a: Surface of protective film formation film

130a: Area on the side of the adhesive layer

14: peeling film

15: Adhesive layer for fixture

15a: Surface of adhesive layer for fixture

150a: Area on the side of the protective film formation film

230a: Area on the side of the adhesive layer for fixtures

321, 421: first adhesive layer

322, 422: 2nd adhesive layer

322a, 422a: The surface of the second adhesive layer

Fig. 1 is a cross-sectional view schematically showing one embodiment of the composite sheet for forming a protective film of the present invention.

Fig. 2 is a cross-sectional view schematically showing another embodiment of the composite sheet for forming a protective film of the present invention.

Fig. 3 is a cross-sectional view schematically showing another embodiment of the composite sheet for forming a protective film of the present invention.

4 is a cross-sectional view schematically showing another embodiment of the composite sheet for forming a protective film of the present invention.

"Composite sheet for protective film formation"

The composite sheet for forming a protective film of the present invention is provided with an adhesive layer on a substrate, a film for forming a protective film on the adhesive layer, the adhesive layer has active energy ray curability, and the film for forming a protective film has Thermosetting: The composite sheet for forming a protective film is used to manufacture a semiconductor chip with a protective film. After the composite sheet for forming a protective film is attached to the back surface of the semiconductor wafer by the protective film forming film, Heating to harden the protective film forming film as a protective film, and then dicing the semiconductor wafer to form a semiconductor wafer, then irradiating active energy rays to harden the adhesive layer, and then attaching the semiconductor wafer together with the semiconductor wafer The protective film on the back of the semiconductor chip is picked up together to manufacture a semiconductor chip with a protective film; the adhesive layer is at least combined with the protective film The layer in contact with the forming film contains an alkyl (meth)acrylate copolymer, and the aforementioned alkyl (meth)acrylate copolymer has a (methyl) group consisting of an alkyl group with a carbon number of 8 or more. Structural unit derived from alkyl acrylate.

That is, one embodiment of the composite sheet for forming a protective film of the present invention includes a substrate, an adhesive layer, and a film for forming a protective film; the adhesive is laminated on the substrate, and the film for forming the protective film is laminated On the adhesive layer; the adhesive layer has active energy ray curability, and contains an alkyl (meth)acrylate copolymer in at least the layer in contact with the film for forming the protective film; the (meth)acrylic acid The alkyl ester copolymer is a copolymer having a structural unit derived from an alkyl (meth)acrylate having 8 or more carbon atoms constituting the alkyl group of the alkyl ester; the aforementioned protective film forming film has thermosetting properties; the aforementioned The composite sheet for forming a protective film is used to manufacture a semiconductor chip with a protective film, and includes the following steps: attaching the composite sheet for forming a protective film to the back of the semiconductor wafer by the film for forming a protective film; Harden the film for forming a protective film in the composite sheet for forming a protective film to be attached to form a protective film; cut the semiconductor wafer on which the protective film is formed to form a semiconductor wafer; and irradiate active energy rays to make the film The adhesive layer is hardened, and then the semiconductor chip is picked up together with the protective film attached to the back surface of the semiconductor chip. In addition, in this specification, the laminated structure of a base material and an adhesive layer may be called a "support sheet." In addition, with regard to the composite sheet for forming a protective film, as long as it maintains the laminated structure of the base material, the adhesive layer or its cured product, and the protective film, the protective film is hardened by heating to form a protective film. Composite sheet, or after curing the aforementioned adhesive layer by irradiating active energy rays The composite sheet is also called a composite sheet for forming a protective film.

In the composite sheet for forming a protective film of the present invention, the layer in contact with the film for forming a protective film in the adhesive layer contains the alkyl (meth)acrylate copolymer in the specified range as described above, whereby the adhesive layer Before the agent layer is cured, the peeling force between the adhesive layer and the cured protective film forming film (i.e., protective film) is large enough to firmly and stably fix the semiconductor wafer, so wafer spatter during dicing of the semiconductor wafer is suppressed. It can cut stably.

In addition, when the composite sheet for forming a protective film is used, the protective film may be attached to the back surface of the semiconductor wafer. The protective film is irradiated with a laser beam, and printing is performed on the surface of the protective film (hereinafter, sometimes referred to as "laser printing"). At this time, along with laser printing, gas is generated from the protective film irradiated part by the laser beam due to the decomposition of the protective film. However, since the peeling force between the adhesive layer and the protective film is sufficiently large as described above, even if the generated The pressure of the gas, the peeling of the adhesive layer and the protective film are also suppressed, and the occurrence of gas retention is suppressed. As a result, not only can cutting be stably performed as described above, but also the printing applied on the protective film can be clearly visually recognized through the substrate and the adhesive layer.

On the other hand, in the composite sheet for forming a protective film of the present invention, the layer in contact with the film for forming a protective film in the adhesive layer contains the alkyl (meth)acrylate copolymer in the specific range as described above, and So, in the adhesive After the layer is cured, the peeling force between the cured product of the adhesive layer and the protective film is small enough to stably and easily pick up the semiconductor chip with the protective film, and the cracks or chipping of the chip during picking is suppressed.

Hereinafter, each structure of the composite sheet for forming a protective film of the present invention will be described in detail.

<Substrate>

The material of the substrate is preferably various resins. Specific examples thereof include polyethylene (low-density polyethylene (sometimes abbreviated as LDPE), linear low-density polyethylene (sometimes abbreviated as LLDPE), and high-density polyethylene. Ethylene (sometimes referred to as HDPE, etc.)), polypropylene, ethylene-propylene copolymer, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride film, vinyl chloride copolymer, polyterephthalic acid Ethylene glycol, polyethylene naphthalate, polybutylene terephthalate, polyurethane, polyacrylate urethane, polyimide, ethylene-vinyl acetate copolymer, ionic polymer Resin, ethylene-(meth)acrylic copolymer, ethylene-(meth)acrylate copolymer, polystyrene, polycarbonate, fluororesin, hydrogenated product, modified product, crosslinked product of any of these resins Copolymer etc.

Furthermore, in this specification, the concept of "(meth)acrylic acid" includes both "acrylic acid" and "methacrylic acid".

The thickness of the substrate can be appropriately selected according to the purpose, and is preferably 50 μm to 300 μm, more preferably 60 μm to 100 μm. By making the thickness of the base material within the above range, the flexibility of the composite sheet for forming a protective film and the impact of the semiconductor The adhesion of bulk wafers or semiconductor chips is further improved.

The "thickness" in this manual can be obtained by the method specified in JIS K 7130: 1999 (ISO 4593: 1993).

The base material may be composed of one layer (single layer), or may be composed of two or more layers. When the base material is composed of multiple layers, these multiple layers may be the same or different from each other. That is, all the layers may be the same, all the layers may be different, or only a part of the layers may be the same. In addition, when the plural layers are different from each other, the combination of these plural layers is not particularly limited. Here, the term that the plural layers are different from each other means that at least one of the material and thickness of each layer is different from each other.

In addition, when the substrate is composed of a plurality of layers, the total thickness of each layer may be the above-mentioned preferable substrate thickness.

The surface of the substrate can also be subjected to the following treatments to improve the adhesion with the adhesive layer provided on the substrate: uneven treatment by sandblasting, solvent treatment, etc.; corona discharge treatment, electron beam irradiation treatment, Plasma treatment, ozone/ultraviolet radiation treatment, flame treatment, chromic acid treatment, hot air treatment and other oxidation treatments. In addition, the surface of the substrate may also be subjected to primer treatment.

<Adhesive layer>

The adhesive layer has active energy ray curability, and contains an alkyl (meth)acrylate copolymer in at least the layer in contact with the film for forming the protective film. Among them, the aforementioned (meth)acrylic acid alkyl ester copolymer has A structural unit derived from an alkyl (meth)acrylate having 8 or more carbon atoms in the alkyl group constituting the alkyl ester.

The so-called "derivatization" refers to changes in chemical structure due to polymerization.

In addition, in this specification, the term "active energy rays" means those having energy quantum in electromagnetic waves or charged particle beams, and examples thereof include ultraviolet rays, electron beams, and the like.

The ultraviolet light can be irradiated using, for example, a high-pressure mercury lamp, a fusion H-type lamp, or a xenon lamp as an ultraviolet source. The electron beam can be irradiated with an electron beam generated by an electron beam accelerator or the like.

The thickness of the adhesive layer can be appropriately selected according to the purpose, and is preferably 1 μm to 100 μm, more preferably 1 μm to 60 μm, particularly preferably 1 μm to 30 μm.

The adhesive layer is formed of an adhesive composition containing the aforementioned alkyl (meth)acrylate copolymer or the like. The content ratio of the components that do not vaporize at room temperature in the adhesive composition is usually the same as the content ratio of the aforementioned components in the adhesive layer. Furthermore, in this specification, the "normal temperature" refers to a temperature that is not particularly cold or particularly hot, that is, a normal temperature, for example, a temperature of 15°C to 25°C, etc.

Next, the adhesive composition containing the alkyl (meth)acrylate copolymer, the adhesive composition and the components contained in the adhesive will be described.

[Adhesive composition]

((Meth)acrylic acid alkyl ester copolymer)

The aforementioned alkyl (meth)acrylate copolymer has a structural unit derived from an alkyl (meth)acrylate having 8 or more carbon atoms constituting the alkyl group of the alkyl ester. In addition, in this specification, unless otherwise specified, the abbreviation "(meth)acrylate alkyl ester" refers to the above-mentioned "(meth)acrylic acid with 8 or more carbon atoms constituting the alkyl ester. Alkyl ester".

The alkyl (meth)acrylate having 8 or more carbon atoms may be linear, branched, or cyclic. When it is cyclic, it may be monocyclic or polycyclic. One kind, but preferably linear or branched.

The number of carbon atoms in the alkyl group constituting the aforementioned alkyl ester may be 8 or more, and for example, it may be 11 or more. In addition, the number of carbon atoms in the alkyl group constituting the aforementioned alkyl ester is preferably 18 or less. That is, in the carbon number of the alkyl group constituting the aforementioned alkyl ester, a preferable range can be 8 to 18, and 11 to 18 can be mentioned as an example. The alkyl (meth)acrylate having 19 or more carbon atoms constituting the alkyl ester has problems such as low solubility and is difficult to handle. That is, if the carbon number of the alkyl group constituting the alkyl ester is 18 or less, the solubility is good and handling is easy.

In addition, by using the aforementioned alkyl (meth)acrylate copolymer having 8 or more carbon atoms constituting the alkyl ester, and using the aforementioned alkyl (meth)acrylate copolymer having less than 7 carbon atoms Compared with the situation, the polarity of the adhesive layer is low. Therefore, for example, when the protective film formation film contains a high-polarity material such as epoxy resin, the high-polarity material can be suppressed in the composite sheet for the protective film formation Transfer from the film for forming a protective film to the adhesive layer. As a result, it is possible to effectively suppress a decrease in the thermosetting properties of the protective film forming film. In addition, the thermal curing degree of the protective film forming film hardened by heating is improved, so the pick-up of the semiconductor wafer with the protective film described later is improved.

Among the aforementioned alkyl (meth)acrylates having 8 or more carbon atoms, preferred ones include n-octyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylic acid. -2-ethylhexyl ester, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, (meth)acrylic acid Lauryl ester (also known as lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (also known as nutmeg (meth)acrylate) Ester), pentadecyl (meth)acrylate, cetyl (meth)acrylate (also known as palmetyl (meth)acrylate), heptadecyl (meth)acrylate, (meth) Base) stearyl acrylate (also known as stearyl (meth)acrylate), isostearyl (meth)acrylate (also known as isostearyl (meth)acrylate), etc. The aforementioned alkyl group is a chain-like alkyl (meth)acrylate; cycloalkyl (meth)acrylate such as isobornyl (meth)acrylate and dicyclopentyl (meth)acrylate.

Among the above, preferred are 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and isostearyl (meth)acrylate.

Examples of the aforementioned (meth)acrylic acid alkyl ester copolymer include active energy ray polymerizable copolymers that are polymerized by irradiation with active energy rays. Among such copolymers, preferred ones include, for example, having hydroxyl groups and side chains having poly Binding groups (for example, (meth)acrylic group, ethenyl group, allyl (2-propenyl), etc., preferably (meth)acrylic group) copolymers; Among them, a copolymer having a hydroxyl group and having a polymerizable group in a side chain via a urethane bond is more preferable. Such an alkyl (meth)acrylate copolymer is crosslinked by, for example, reacting the hydroxyl group it has with the isocyanate group in the isocyanate-based crosslinking agent described later. In addition, since this alkyl (meth)acrylate copolymer has a polymerizable group in the side chain, for example, a low molecular weight active energy ray polymerizable compound is used separately, and the polymerization reaction proceeds by irradiating the active energy ray. Compared with the situation, the polymerization reaction can be carried out without using such a compound separately. By this, the adhesive layer after the polymerization reaction is peeled off from the protective film due to the decrease in adhesiveness, and the releasability of the protective film can be easily picked up. The pick-up is improved. In addition, since it is not necessary to use a low molecular weight active energy ray polymerizable compound separately, it is possible to suppress the transfer of such low molecular weight active energy ray polymerizable compound from the adhesive layer to the protective film forming film, and it is possible to suppress the film for forming the protective film. The characteristics have changed.

The above-mentioned preferred alkyl (meth)acrylate copolymer is obtained, for example, by the following method: using a composition containing alkyl (meth)acrylate and hydroxyl-containing monomers, polymerizing these monomers is obtained After the copolymer (hereinafter, sometimes referred to as "precopolymer"), the hydroxyl group of the copolymer (precopolymer) is reacted with the isocyanate group of the compound having an isocyanate group and a polymerizable group.

Among the aforementioned (meth)acrylic acid alkyl ester copolymers, more preferred ones include, for example, copolymers obtained by using the aforementioned (meth)acrylic acid alkyl esters and hydroxyl group-containing (meth)acrylates. As an essential monomer, the hydroxyl group of the pre-copolymer obtained by copolymerizing these monomers reacts with the isocyanate group of the compound having an isocyanate group and a polymerizable group.

Examples of the hydroxyl group-containing (meth)acrylate include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and the like.

Examples of the compound having an isocyanate group and a polymerizable group include: 2-(meth)acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, and methacrylic acid Isocyanate compounds such as methyl isocyanate and allyl isocyanate; among these, 2-methacryloxyethyl isocyanate is preferred.

The above-mentioned preferred (meth)acrylic acid alkyl ester copolymer may be obtained by reacting any other compound in addition to the above-mentioned essential monomers and compounds. Any of the foregoing compounds may be monomers or It can be a compound formed by copolymerization of monomers. Examples of monomers as any of the aforementioned compounds include: (meth)acrylate, (meth)acrylic acid, itaconic acid, non-(meth)acrylic acid, which does not correspond to the aforementioned alkyl (meth)acrylate and does not contain a hydroxyl group. Acrylic monomers, etc.

Examples of (meth)acrylates containing no hydroxyl groups include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, ( Alkyl (meth)acrylates such as amyl methacrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, etc. The alkyl group constituting the alkyl ester in these alkyl (meth)acrylates is Straight-chain or branched chain with carbon number of 1 to 7; aralkyl (meth)acrylates such as benzyl (meth)acrylate; (meth)acrylic rings such as dicyclopentenyl (meth)acrylate Alkenyl ester; (meth) cyclopentenyloxy ethyl acrylate and other cycloalkenyloxy alkyl esters; (meth) acryl imine; (meth) glycidyl acrylate, etc. Glycidyl (meth)acrylate etc.

As said non-(meth)acrylic-type monomer, vinyl acetate, acrylonitrile, styrene, N-methylol acrylamide etc. are mentioned, for example.

The aforementioned alkyl (meth)acrylates, hydroxyl-containing (meth)acrylates, compounds having isocyanate groups and polymerizable groups, and any of the aforementioned compounds are used to prepare the aforementioned alkyl (meth)acrylate copolymers Any of the components (that is, the constituent components of the aforementioned copolymer) may be only one type or two or more types.

The ratio of the alkyl (meth)acrylate having 8 or more carbon atoms in the aforementioned alkyl group is as follows: relative to the total mass of all monomers used in the preparation of the aforementioned alkyl (meth)acrylate copolymer, it is preferably 30 Mass% or more, more preferably 35% by mass or more.

In other words, the content of the structural unit derived from the alkyl (meth)acrylate having 8 or more carbon atoms in the above-mentioned alkyl group is as follows: relative to the total mass of all structural units constituting the aforementioned alkyl (meth)acrylate copolymer , Preferably 30% by mass or more, more preferably 35% by mass or more.

On the other hand, the upper limit of the content of the structural unit derived from the alkyl (meth)acrylate having 8 or more carbon atoms in the above-mentioned alkyl group is not particularly limited. The total mass of all the structural units of the copolymer can be any content selected from, for example, 85% by mass, 90% by mass, and 95% by mass, and it can also be 100% by mass.

That is, the ratio of the alkyl (meth)acrylate having 8 or more carbon atoms in the above-mentioned alkyl group is as follows: relative to the total mass of all monomers used in the preparation of the aforementioned alkyl (meth)acrylate copolymer, It may be 30% by mass or more and 100% by mass or less, and may be 30% by mass or more and 95% by mass or less, or 30% by mass or more and 90% by mass or less, or 30% by mass or more and 85% by mass or less.

On the other hand, the above content may be 35 mass% or more and 100 mass% or less, or 35 mass% or more and 95 mass% or less, or 35 mass% or more and 90 mass% or less, or 35 mass% or more. 85% by mass or less.

As yet another aspect, the aforementioned content may be 40% by mass or more and 80% by mass or less.

As yet another aspect, the content of structural units derived from the alkyl (meth)acrylate having 8 or more carbon atoms in the alkyl group is as follows: relative to all the structural units constituting the aforementioned alkyl (meth)acrylate copolymer Total mass , It may be 30% by mass or more and 100% by mass or less, or 30% by mass or more and 95% by mass or less, 30% by mass or more and 90% by mass or less, or 30% by mass or more and 85% by mass or less.

As yet another aspect, the above content may be 35 mass% or more and 100 mass% or less, or 35 mass% or more and 95 mass% or less, or 35 mass% or more and 90 mass% or less, or 35 mass% or more. 85% by mass or less.

As yet another aspect, the aforementioned content may be 40% by mass or more and 80% by mass or less.

The aforementioned alkyl (meth)acrylate copolymer contained in the adhesive layer may be only one type or two or more types.

The content of the aforementioned alkyl (meth)acrylate copolymer relative to the total mass of the adhesive layer is preferably 75% by mass or more, and more preferably 80% by mass or more. In addition, in order to form such an adhesive layer, the content of the alkyl (meth)acrylate copolymer in the adhesive composition is lower than the total mass of all components in the adhesive composition except the solvent. It is preferably 75% by mass or more, and more preferably 80% by mass or more.

On the other hand, the upper limit of the content of the aforementioned alkyl (meth)acrylate copolymer in the adhesive layer is not particularly limited. It may be 100% by mass relative to the total mass of the adhesive layer, but it is considered As described later, other components are generally used together, and the upper limit is preferably 97% by mass, and more preferably 95% by mass.

That is, the content of the aforementioned alkyl (meth)acrylate copolymer relative to the total mass of the adhesive layer may be 75% by mass or more and 100% by mass or less, preferably 75% by mass or more and 97% by mass or less, and more Preferably, it is 80% by mass or more and 95% by mass or less.

On the other hand, the content of the alkyl (meth)acrylate copolymer in the adhesive composition is 75% by mass or more and 100% by mass relative to the total mass of all components except the solvent in the adhesive composition % Or less, preferably 75% by mass or more and 97% by mass or less, more preferably 80% by mass or more and 95% by mass or less.

When the alkyl (meth)acrylate copolymer has a hydroxyl group and further has a polymerizable group in the side chain, the preferred adhesive composition includes, for example, in addition to the alkyl (meth)acrylate copolymer In addition to the product, a composition further containing an isocyanate-based crosslinking agent and a photopolymerization initiator.

(Isocyanate-based crosslinking agent)

The aforementioned isocyanate-based crosslinking agent is not particularly limited as long as it is a crosslinking agent having an isocyanate group (-N=C=O). Preferred examples include: 2,4-toluene diisocyanate; 2,6-toluene diisocyanate ; 1,3-xylene diisocyanate; 1,4-xylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyl Diphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; p-three All or part of the hydroxyl groups of polyols such as methylol propane , Addition of at least one compound of toluene diisocyanate, hexamethylene diisocyanate and xylylene diisocyanate; lysine diisocyanate, etc.

The isocyanate-based crosslinking agent contained in the aforementioned adhesive composition may be only one type or two or more types.

The content of the isocyanate-based crosslinking agent in the adhesive composition is as follows: When the content of the alkyl (meth)acrylate copolymer is 100 parts by mass, the content of the isocyanate-based crosslinking agent is preferably 0.01 mass Parts to 20 parts by mass, more preferably 0.1 parts by mass to 10 parts by mass.

(Photopolymerization initiator)

The aforementioned photopolymerization initiator may be a known photopolymerization initiator. Specifically, for example, 4-(2-hydroxyethoxy)-phenyl-(2-hydroxy-2-propyl)ketone, α-Hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1-{4-[4-(2 -Hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one and other α-keto alcohol compounds; methoxyacetophenone, 2,2-di Methoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- Acetophenone-based compounds such as 1-ketone; Benzoin ether-based compounds such as ethyl benzoin, isopropyl benzoin, and methyl anisin; ketal compounds such as benzil dimethyl ketal; 2-naphthalenesulfonyl chloride Aromatic sulfonyl chloride compounds; 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime and other optically active oxime compounds ; Benzophenone compounds such as benzophenone, benzoic acid and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone Ketone, 2-Methylthioxanthone, 2,4-Dimethylthioxanthone, Isopropylthioxanthone, 2,4-Dichlorothioxanthone, 2,4-Diethylthioxanthone, 2 , 4-Diisopropylthioxanthone and other thioxanthone compounds; camphorquinone; halogenated ketones; phosphine oxides; phosphonates/esters, etc.

The content of the photopolymerization initiator in the adhesive composition is as follows: When the content of the alkyl (meth)acrylate copolymer is 100 parts by mass, it is preferably 0.05 to 20 parts by mass.

(Solvent)

The aforementioned adhesive composition preferably further contains a solvent in addition to the aforementioned (meth)acrylic acid alkyl ester copolymer.

The aforementioned solvent is not particularly limited. Preferred solvents include, for example, hydrocarbons with 7 to 9 carbon atoms such as toluene and xylene; methanol, ethanol, 2-propanol, isobutanol (also known as 2-methylpropane- 1-alcohol), 1-butanol and other C1-C6 alcohols; ethyl acetate and other esters; acetone, methyl ethyl ketone and other ketones; tetrahydrofuran and other ethers; dimethylformamide, N-methylpyrrole Amide such as pyridone (that is, a compound having an amide bond) and the like.

Among the above, methyl ethyl ketone, toluene, and ethyl acetate are preferred.

The solvent contained in the aforementioned adhesive composition may be only one type or two or more types.

The content of the solvent when the adhesive composition contains a solvent is preferably such that the solid content concentration of the composition is 10 to 50% by mass relative to the total mass of the composition.

(Other ingredients)

In addition to the aforementioned (meth)acrylic acid alkyl ester copolymer, the aforementioned adhesive composition may also contain a crosslinking agent that does not belong to the aforementioned isocyanate-based crosslinking agent, photopolymerization initiator, and Any other component of the solvent.

The aforementioned other components may be well-known components, which can be arbitrarily selected according to the purpose and are not particularly limited. Preferred examples include: dyes, pigments, anti-deterioration agents, antistatic agents, flame retardants, polysiloxanes, chain transfer Additives and other additives.

The aforementioned adhesive layer may be composed of one layer (single layer), or may be composed of two or more layers. When the adhesive layer is composed of plural layers, these plural layers may be the same or different from each other. That is, all the layers may be the same, all the layers may be different, or only a part of the layers may be the same. In addition, when the plural layers are different from each other, the combination of these plural layers is not particularly limited. Here, the so-called "a plurality of layers are different from each other" has the same meaning as the aforementioned base material.

Wherein, when the adhesive layer is composed of one layer (single layer), the adhesive layer must be a layer containing the aforementioned alkyl (meth)acrylate copolymer obtained by using the aforementioned adhesive composition. In addition, the adhesive layer is composed of multiple layers At the time of formation, among these plural layers, at least the layer in contact with the aforementioned protective film formation film (that is, the layer farthest from the substrate in the thickness direction of the adhesive layer, hereinafter sometimes referred to as the uppermost layer) must be used A layer containing the aforementioned alkyl (meth)acrylate copolymer obtained from the adhesive composition. When the adhesive layer is composed of multiple layers, all layers other than the layer in contact with the protective film forming film may be layers containing the aforementioned (meth)acrylic acid alkyl ester copolymer, or all of them may not contain the aforementioned ( The layer of the alkyl meth)acrylate copolymer may be only a part of the layer containing the aforementioned alkyl (meth)acrylate copolymer.

When the adhesive layer is composed of a single layer, the structure of the composite sheet for forming a protective film is simplified, which has an advantage that it can be manufactured at low cost.

On the other hand, when the adhesive layer is composed of a plurality of layers, as described above, the layer (that is, the uppermost layer) in contact with the protective film forming film of the plurality of layers contains the (meth)acrylic alkyl group. The layer of ester copolymer can obtain the effect of the present invention. Furthermore, by making the layer in contact with the aforementioned substrate among these plural layers (that is, the layer adjacent to the substrate in the thickness direction of the adhesive layer, hereinafter sometimes referred to as the lowermost layer), for example, In a layer with particularly high adhesiveness, the stability during use of the composite sheet for forming a protective film is further improved. In this way, by making the aforementioned adhesive layer a laminated body composed of a plurality of layers, there is an advantage that the adhesive layer can be adjusted to a layer having two or more characteristics as a whole.

When the adhesive layer is composed of multiple layers, it does not contain the aforementioned (meth)acrylate The adhesive layer of the base ester copolymer may be the same layer as the previous adhesive layer, for example.

When the adhesive layer is composed of a plurality of layers, the total thickness of each layer may be the thickness of the above-mentioned preferable adhesive layer.

<Film for forming protective film>

The above-mentioned protective film formation film has thermosetting properties and may also have pressure-sensitive adhesive properties, or may be softened by heating to be able to be attached to various adherends. After the protective film formation film is thermally cured, it finally becomes a protective film with high impact resistance. The protective film is excellent in shear strength and maintains sufficient adhesive properties even under severe high temperature and high humidity conditions.

The thickness of the protective film formation film is not particularly limited, but is preferably 1 μm to 100 μm, more preferably 5 μm to 75 μm, and particularly preferably 5 μm to 50 μm. By making the thickness of the protective film forming film more than the aforementioned lower limit, the adhesive force to the adherend, that is, the semiconductor wafer and the semiconductor wafer becomes greater. In addition, by setting the thickness of the protective film forming film to the aforementioned upper limit or less, the protective film as the cured product can be cut more easily by shearing force when picking up the semiconductor wafer.

The film for forming a protective film is not particularly limited as long as it is a film having thermosetting properties.

As a preferable film for forming a protective film, for example: A film of material component (A) and thermosetting component (B). The polymer component (A) can be regarded as a component formed by the polymerization reaction of a polymerizable compound.

In addition, the thermosetting component (B) is a component that can undergo a curing (polymerization) reaction by heat. Furthermore, the polymerization reaction in the present invention also includes a polycondensation reaction.

[Composition for forming protective film]

The protective film formation film can be formed of a protective film formation composition containing components for constituting the protective film formation film. The content ratio of the components that do not vaporize at room temperature in the protective film formation composition is usually the same as the content ratio of the aforementioned components of the protective film formation film.

As a preferable composition for forming a protective film, for example, a composition containing a polymer component (A) and a thermosetting component (B) is mentioned, and it is more preferable to contain a polymer component (A) and a thermosetting component (B). ) And hardening accelerator (C). Hereinafter, the components contained in the composition for forming a protective film and the film for forming a protective film will be described.

(Polymer component (A))

The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, or the like to the protective film forming film. The polymer component (A) may also be a thermosetting component (B).

For example, phenoxy resin, acrylic resin having an epoxy group in the side chain, etc. belong to the polymer component (A), and sometimes also belong to the thermosetting component (B). Such a component can be treated as the polymer component (A).

The polymer component (A) can be used singly, or two or more can be used simultaneously use.

As the polymer component (A), for example, acrylic resin, polyester, polyurethane, acrylic urethane resin, polysiloxane resin, rubber-based polymer, phenoxy resin, etc. may be mentioned; preferably It is an acrylic resin.

As the aforementioned acrylic resin, a known acrylic polymer can be used.

The weight average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000. By setting the weight average molecular weight of the acrylic resin to be equal to or higher than the aforementioned lower limit, the adhesion between the protective film described later and the adhesive layer after curing is suppressed, and the pick-up of the semiconductor wafer with the protective film is further improved.

In addition, by making the weight average molecular weight of the acrylic resin below the aforementioned upper limit, the protective film forming film can easily follow the uneven surface of the adherend, thereby further suppressing the generation of gaps between the adherend and the protective film forming film. .

In addition, unless otherwise specified in this specification, the so-called "weight average molecular weight" refers to a polystyrene conversion value measured by a gel permeation chromatography (GPC, Gel Permeation Chromatography) method.

The glass transition temperature (Tg) of the acrylic resin is preferably -60°C to 70°C, more preferably -30°C to 50°C. By making the Tg of the acrylic resin more than the aforementioned lower limit, the protective film described later and the aforementioned adhesive layer after curing The peeling force becomes smaller, and the pick-up of semiconductor wafers with protective film is further improved. In addition, by setting the Tg of the acrylic resin to be equal to or lower than the aforementioned upper limit value, the adhesive force between the protective film forming film and the semiconductor wafer is increased, and the semiconductor wafer can be more stably fixed.

Examples of monomers constituting acrylic resins include: (meth)acrylic acid alkyl esters whose alkyl groups constituting alkyl esters are in a chain shape and have a carbon number of 1 to 18, (meth)acrylate, (meth) Base) ethyl acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-(meth)acrylate Octyl ester, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (Lauryl (meth)acrylate), Tridecyl (meth)acrylate, Myristyl (meth)acrylate (Myristyl (meth)acrylate), Pentadecane (meth)acrylate Base ester, cetyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, stearyl (meth)acrylate ((meth)acrylic acid) Stearyl ester) etc.; (meth)acrylate with cyclic skeleton, cycloalkyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, (meth) Dicyclopentyl acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, (meth)acrylimide, etc.; hydroxyl-containing (meth)acrylate , Hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.; (meth)acrylate containing glycidyl groups, (methyl) ) Glycidyl acrylate, etc.

In addition, acrylic resins can also be acrylic, methacrylic, or clothing Co-polymerized monomers such as aconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylol acrylamide.

The monomer constituting the acrylic resin may be only one type or two or more types.

Acrylic resins may also have functional groups such as vinyl groups, (meth)acrylic groups, amino groups, hydroxyl groups, carboxyl groups, and isocyanate groups that can be bonded to other compounds. The aforementioned functional group may be bonded to other compounds via the crosslinking agent (F) described later, or may be directly bonded to other compounds without the crosslinking agent (F). By bonding the acrylic resin to other compounds using the aforementioned functional groups, there is a tendency to improve the reliability of packaging of semiconductor devices obtained by using a composite sheet for forming a protective film.

When the composition for forming a protective film contains acrylic resin as the polymer component (A), the content of the acrylic resin in the composition for forming a protective film is relative to all the components in the composition for forming a protective film except the solvent The total mass is preferably 5 to 50% by mass. By setting the content of the acrylic resin in the above range, the peeling force between the protective film and the adhesive layer after curing becomes small, and the pick-up of the semiconductor wafer with the protective film is further improved.

In this way, when the protective film forming film contains acrylic resin as the polymer component (A), the content of the acrylic resin in the protective film forming film is preferably from 5 mass% to the total mass of the protective film forming film 50% by mass.

In the present invention, with regard to the following aspects, by reducing the adhesive force (sometimes referred to as peeling force) between the protective film and the cured adhesive layer, the pick-up of the semiconductor chip with the protective film is further improved , Or to make the protective film forming film easy to follow the uneven surface of the adherend, thereby further suppressing the gap between the adherend and the protective film forming film, etc., as the polymer component (A), it can be used alone Thermoplastic resins other than acrylic resins (hereinafter sometimes referred to as "thermoplastic resins") may also be used together with acrylic resins.

The weight average molecular weight of the aforementioned thermoplastic resin is preferably 1,000 to 100,000, more preferably 3,000 to 80,000.

The glass transition temperature (Tg) of the aforementioned thermoplastic resin is preferably -30°C to 150°C, more preferably -20°C to 120°C.

As said thermoplastic resin, polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, polystyrene, etc. are mentioned, for example.

The aforementioned thermoplastic resin may be used singly or in combination of two or more kinds.

(Thermosetting component (B))

The thermosetting component (B) is used to harden the protective film forming film to form It is a component of a hard protective film. The thermosetting component (B) may also belong to the polymer component (A), and this component is treated as the polymer component (A).

The thermosetting component (B) may be used alone or in combination of two or more kinds.

Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimide resins, polyurethanes, unsaturated polyesters, silicone resins, etc.; preferably Epoxy-based thermosetting resin.

‧Epoxy-based thermosetting resin

The epoxy-based thermosetting resin is composed of an epoxy resin (B11) and a thermosetting agent (B12).

Epoxy-based thermosetting resins may be used singly or in combination of two or more.

As the epoxy resin (B11), known ones can be mentioned, for example, the following bifunctional or more epoxy compounds: polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydrogenated products, o-methyl Phenolic novolac epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenylene skeleton epoxy resin, etc. Among the above, bisphenol A type epoxy resin and dicyclopentadiene type epoxy resin are preferable.

The epoxy resin (B11) can also use epoxy resins with unsaturated hydrocarbon groups.

As an epoxy resin having an unsaturated hydrocarbon group, for example, a compound in which a part of the epoxy group of a polyfunctional epoxy resin is replaced with an unsaturated hydrocarbon group-containing group is mentioned.

The number average molecular weight of the epoxy resin (B11) is not particularly limited, but it is preferably 100 to 20,000 from the viewpoint of the curability of the protective film forming film, and the strength and heat resistance of the protective film after curing.

The "number average molecular weight" referred to here is a polystyrene conversion value measured by gel permeation chromatography (GPC).

The epoxy equivalent of the epoxy resin (B11) is preferably 100 g/eq to 1100 g/eq, more preferably 150 g/eq to 1000 g/eq.

The epoxy resin (B11) may be used individually by 1 type, and may use 2 or more types together.

The thermal hardener (B12) functions as a hardener for the epoxy resin (B11).

As a thermosetting agent (B12), the compound which has 2 or more functional groups which can react with an epoxy group in 1 molecule is mentioned, for example. Examples of the aforementioned functional groups include: phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, acid groups formed by anhydrides, etc.; preferably, phenolic hydroxyl groups, amino groups, or acid groups formed by anhydrides The group is more preferably a phenolic hydroxyl group or an amino group, and particularly preferably an amino group.

Among the thermosetting agents (B12), as a phenolic curing agent with phenolic hydroxyl group, For example, polyfunctional phenol resin, biphenol, novolak type phenol resin, dicyclopentadiene type phenol resin, aralkyl phenol resin, etc. are mentioned.

In the thermosetting agent (B12), examples of the amine-based curing agent having an amine group include dicyandiamine (hereinafter, abbreviated as "DICY") and the like.

The thermosetting agent (B12) may have an unsaturated hydrocarbon group.

As the thermosetting agent (B12) having an unsaturated hydrocarbon group, for example, a compound in which a part of the hydroxyl group of a phenol resin is substituted with a group having an unsaturated hydrocarbon group; the aromatic ring of the phenol resin is directly bonded to the one having an unsaturated hydrocarbon group Compounds etc.

The aforementioned unsaturated hydrocarbon group in the thermosetting agent (B12) is the same as the aforementioned unsaturated hydrocarbon group in the epoxy resin having an unsaturated hydrocarbon group.

The thermosetting agent (B12) may be used alone or in combination of two or more.

The thermal hardener (B12) is preferably solid at room temperature and does not show hardening activity to epoxy resin (B11). On the other hand, it is dissolved by heating and shows hardening activity to epoxy resin (B11). Hardener (hereinafter sometimes referred to as "solid dispersion type latent hardener"). That is, the film for forming a protective film preferably contains an epoxy resin (B11) and the aforementioned solid dispersion type latent curing agent as a thermosetting agent (B12).

The aforementioned solid dispersion type latent curing agent is stably dispersed in the epoxy resin (B11) in the protective film formation film at room temperature, but it is The epoxy resin (B11) is compatible and reacts with the epoxy resin (B11). By using the solid dispersion type latent curing agent, the storage stability of the composite sheet for forming a protective film is significantly improved. For example, it is possible to suppress the transfer of the curing agent from the film for forming a protective film to the adjacent adhesive layer, and it is possible to effectively suppress a decrease in the thermosetting properties of the film for forming a protective film. In addition, the degree of thermal curing of the protective film forming film by heating is further improved, so the pick-up of the semiconductor wafer with a protective film described later is further improved.

Examples of the aforementioned solid dispersion type latent curing agent include onium salts, dibasic acid hydrazine, dicyandiamine, and amine adducts of curing agents.

The content of the thermosetting agent (B12) in the protective film forming composition and the protective film forming film is as follows: When the content of the epoxy resin (B11) is 100 parts by mass, it is preferably 0.1 to 500 parts by mass , More preferably 1 part by mass to 200 parts by mass. By making the said content of a thermosetting agent (B12) more than the said lower limit, the hardening of the film for protective film formation becomes more easy.

In addition, by making the aforementioned content of the thermosetting agent (B12) below the aforementioned upper limit value, the moisture absorption rate of the protective film formation film is reduced, and the packaging reliability is further improved.

The content of the thermosetting component (B) in the protective film forming composition and the protective film forming film is as follows: when the content of the polymer component (A) is 100 parts by mass, it is preferably 1 part by mass to 100 parts by mass Parts, more preferably 1.5 parts by mass to 85 parts by mass, particularly preferably 2 parts by mass to 70 parts by mass. By hardening the heat The aforementioned content of the chemical component (B) is within the aforementioned range, the adhesive force (peeling force) of the protective film and the cured adhesive layer is further reduced, and the pick-up of the semiconductor wafer with the protective film is further improved.

(Hardening accelerator (C))

The curing accelerator (C) is a component for adjusting the curing speed of the protective film forming composition.

As a preferable hardening accelerator (C), for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol can be cited; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5- Imidazoles such as hydroxymethylimidazole (that is, imidazoles in which at least one hydrogen atom is replaced by a group other than hydrogen); organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine (at least one hydrogen atom is Phosphine substituted with organic groups); tetraphenyl boron salts such as tetraphenyl phosphonium tetraphenyl borate, triphenyl phosphine tetraphenyl borate, etc.

Among the above, 2-phenyl-4,5-dimethylolimidazole is preferred.

The hardening accelerator (C) may be used alone or in combination of two or more kinds.

In particular, when the composition for forming a protective film contains the aforementioned solid dispersion type latent curing agent as a thermosetting agent (B12), it is preferable to contain the aforementioned imidazole as a curing accelerator (C). That is, the film for forming a protective film preferably contains an epoxy resin (B11) and the aforementioned solid dispersion type as a thermosetting agent (B12) Latent hardeners, and imidazoles as hardening accelerators (C).

That is, one aspect of the film for forming a protective film contains a polymer component (A), an epoxy resin (B11), the aforementioned solid dispersion type latent curing agent as a thermosetting agent (B12), and a curing accelerator (C ) Of imidazoles.

When the curing accelerator (C) is used, the content of the curing accelerator (C) in the protective film forming composition and the protective film forming film is as follows: When the content of the thermosetting component (B) is 100 parts by mass, It is preferably 0.01 parts by mass to 10 parts by mass, more preferably 0.1 parts by mass to 4 parts by mass. By setting the aforementioned content of the hardening accelerator (C) within the above range, the protective film forming film has excellent adhesion properties even under high temperature and high humidity conditions, and can be achieved even when exposed to severe reflow soldering conditions High package reliability. By setting the aforementioned content of the hardening accelerator (C) to be at least the aforementioned lower limit value, a more remarkable effect by using the hardening accelerator (C) can be obtained. In addition, although the hardening accelerator (C) usually has a high polarity, by making the content of the hardening accelerator (C) below the upper limit, it is possible to suppress the hardening accelerator (C) under high temperature and high humidity conditions. ) Precipitating at the bonding interface with the adherend in the protective film forming film, thereby improving the reliability of the package.

In order to improve the various physical properties of the protective film forming film, the protective film forming film may also contain in addition to the polymer component (A), the thermosetting component (B) and the curing accelerator (C), if necessary, other components that do not belong to these The other components of the protective film formation composition.

Contained as a protective film forming composition and a protective film forming film Examples of the aforementioned other components include filler (D), coupling agent (E), crosslinking agent (F), and general-purpose additives (G).

(Filling material (D))

Generally, by containing the filler (D), it becomes easy to adjust the thermal expansion coefficient of the protective film forming composition. Therefore, by using such a protective film forming composition, the thermal expansion coefficient of the cured protective film is optimized for the semiconductor wafer, and the reliability of the package can be improved.

In addition, generally, by using the protective film forming composition containing the filler (D), the moisture absorption rate of the cured protective film can also be reduced.

The filling material (D) may be any one of an organic filling material and an inorganic filling material, preferably an inorganic filling material.

As preferred inorganic fillers, for example, powders such as silica, alumina, talc, calcium carbonate, titanium dioxide, iron oxide, silicon carbide, boron nitride, etc. can be cited; The beads; these single crystal fibers such as silicon dioxide; glass fibers, etc.

Among them, the inorganic filler material is preferably silica filler or alumina filler.

The filler (D) may be used alone or in combination of two or more.

When the filler (D) is used, it will be removed from the protective film forming composition In consideration of the total mass of components other than the solvent, the content of the filler (D) (that is, the content of the filler (D) in the protective film forming film) is preferably 5 mass% to 80 mass%, more preferably 7 mass% To 60% by mass. By setting the content of the filler (D) within the above range, it becomes easier to adjust the above thermal expansion coefficient.

(Coupling agent (E))

By using a compound having a functional group that reacts with an inorganic compound or an organic compound as the coupling agent (E), the adhesion and adhesion of the film for forming a protective film to the adherend can be improved. In addition, by containing the coupling agent (E), the water resistance of the protective film obtained by curing the protective film forming film is improved without impairing heat resistance.

The coupling agent (E) is preferably a compound having a functional group that reacts with the functional group possessed by the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.

As a preferred silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-ring Oxycyclohexyl) ethyl trimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)-γ- Aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyl diethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureido Propyl triethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl) tetrasulfide, methyl Trimethoxysilane, methyl triethyl Oxysilane, vinyl trimethoxysilane, vinyl triacetoxysilane, imidazole silane, etc.

The coupling agent (E) may be used singly or in combination of two or more kinds.

When the coupling agent (E) is used, the content of the coupling agent (E) in the protective film forming composition and the protective film forming film is as follows: Set the total content of the polymer component (A) and the thermosetting component (B) When it is 100 parts by mass, it is preferably 0.03 parts by mass to 20 parts by mass, more preferably 0.05 parts by mass to 10 parts by mass, and particularly preferably 0.1 parts by mass to 5 parts by mass. By making the aforementioned content of the coupling agent (E) more than the aforementioned lower limit, more significant effects brought about by the use of the coupling agent (E) can be obtained, and by making the aforementioned content of the coupling agent (E) the aforementioned upper limit Below the limit, the outgassing can be further suppressed.

(Crosslinker (F))

When using the above-mentioned acrylic resin having functional groups capable of bonding with other compounds, for example, vinyl, (meth)acrylic, amino, hydroxyl, carboxyl, isocyanate and other functional groups as the polymer component (A), In order to bond this functional group to another compound and cause crosslinking, a crosslinking agent (F) can be used. By using the crosslinking agent (F) to cause crosslinking, the initial adhesive force and cohesive force of the protective film formation film can be adjusted.

As a crosslinking agent (F), an organic polyvalent isocyanate compound, an organic polyvalent imine compound, etc. are mentioned, for example.

As the aforementioned organic polyvalent isocyanate compounds, for example, aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, and trimers of these compounds, isocyanurate bodies, and adducts (with ethyl Diol, propylene glycol, neopentyl glycol, trimethylolpropane or castor oil and other reaction products containing low molecular active hydrogen compounds, such as trimethylolpropane xylylene diisocyanate adduct, etc.), or A terminal isocyanate urethane prepolymer obtained by reacting an organic polyisocyanate compound and a polyol compound, etc.

As the aforementioned organic polyvalent isocyanate compound, for example, 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylene diisocyanate; diphenyl Methane-4,4'-Diisocyanate; Diphenylmethane-2,4'-Diisocyanate; 3-Methyldiphenylmethane Diisocyanate; Hexamethylene Diisocyanate; Isophorone Diisocyanate; Bicyclic Hexylmethane-4,4'-diisocyanate; Dicyclohexylmethane-2,4'-diisocyanate; All or part of the hydroxyl groups of polyols such as trimethylolpropane, adding toluene diisocyanate and hexamethylene diisocyanate Any one of isocyanate or a compound of both; lysine diisocyanate, etc.

As the aforementioned organic polyimine compound, for example, N,N'-diphenylmethane-4,4'-bis(1-aziridine methamide), trimethylolpropane-tri-β-nitrogen Propidinyl propionate, tetramethylolmethane-tris-β-aziridinyl propionate, N,N'-toluene-2,4-bis(1-aziridinylmethamine) triethylene Melamine Wait.

When an isocyanate-based crosslinking agent is used as the crosslinking agent (F), the acrylic resin as the polymer component (A) is preferably a hydroxyl-containing polymer. When the crosslinking agent (F) has an isocyanate group and the acrylic resin has a hydroxyl group, the crosslinking structure can be easily introduced into the protective film formation film by the reaction between the crosslinking agent (F) and the acrylic resin .

When the crosslinking agent (F) is used, the content of the crosslinking agent (F) of the composition for forming a protective film is as follows: When the content of the polymer component (A) is 100 parts by mass, it is preferably 0.01 to 20 parts by mass Parts by mass, more preferably 0.1 parts by mass to 10 parts by mass, particularly preferably 0.5 parts by mass to 5 parts by mass.

(General additives (G))

As a general-purpose additive (G), well-known plasticizers, antistatic agents, antioxidants, pigments, dyes, getters, etc. are mentioned, for example.

(Solvent)

The composition for forming a protective film has improved operability by dilution, so it is preferable to further contain a solvent.

The solvent contained in the composition for forming a protective film may be the same as the solvent in the above-mentioned adhesive composition.

The solvent contained in the composition for forming a protective film may be only one type or two or more types.

When the composition for forming a protective film contains a solvent, the solvent content is preferably: relative to the total mass of the composition for forming a protective film, the solid content concentration of the composition for forming a protective film is 35% by mass to 75% by mass the amount.

That is, another aspect of the composition for forming a protective film includes a polymer component (A), a thermosetting component (B), a curing accelerator (C), and if necessary, a solvent, filler (D), At least one component in the group consisting of coupling agent (E), crosslinking agent (F) and general additives (G).

Another aspect of the film for forming a protective film includes a polymer component (A), a thermosetting component (B), a hardening accelerator (C), and if necessary, a filler (D), a coupling agent (E), At least one component in the group consisting of crosslinking agent (F) and general additives (G).

Furthermore, it is preferable that the said thermosetting component (B) contains an epoxy resin (B11), the said solid dispersion type latent hardening agent as a thermosetting agent (B12), and the said hardening accelerator (C) contains an imidazole.

The composition for forming a protective film can be obtained by blending the above-mentioned components to constitute the composition. For example, it can be obtained by the same method as the above-mentioned adhesive composition except for the difference in the blending components.

When a solvent is used, the solvent can be mixed with any compounding component other than the solvent and the compounding component can be pre-diluted and used, or the solvent can be mixed with these compounding components and used without pre-diluting any one other than the solvent Blending ingredients.

The composite sheet for forming a protective film may be provided with a release film on exposed surfaces such as the surface of the film for forming a protective film or the surface of an adhesive layer. When using the composite sheet for protective film formation, what is necessary is just to peel (remove) the said peeling film.

Fig. 1 is a cross-sectional view schematically showing one embodiment of the composite sheet for forming a protective film of the present invention.

The composite sheet 1 for forming a protective film shown here is formed with an adhesive layer 12 on a base material 11 and a protective film forming film 13 on the adhesive layer 12, and has an adhesive on the support sheet 10 The layer 12 is provided with a film 13 for forming a protective film. In addition, the composite sheet 1 for forming a protective film further includes a release film 14 on the film 13 for forming a protective film. The adhesive layer 12 in contact with the protective film forming film 13 is a layer containing the aforementioned alkyl (meth)acrylate copolymer, and the aforementioned alkyl (meth)acrylate copolymer has an alkyl group consisting of an alkyl ester. A structural unit derived from alkyl (meth)acrylate with a carbon number of 8 or more.

In the composite sheet 1 for forming a protective film, the adhesive layer 12 is laminated on the surface 11 a of the base material 11, and the film 13 for forming a protective film is laminated on a part of the surface 12 a of the adhesive layer 12. In addition, on the surface 12a of the adhesive layer 12, the exposed surface on which the protective film forming film 13 is not laminated, and the surface 13a (upper surface and side surface) of the protective film forming film 13, the release film 14 is laminated.

Furthermore, on the peeling film 14, and the surface 12a of the adhesive layer 12 or the protective film There may be voids between the surfaces 13a of the forming film 13. For example, the area indicated by the symbol 130a on the surface 13a of the protective film formation film 13 (the area on the side of the adhesive layer 12) and the area indicated by the symbol 120a on the surface 12a of the adhesive layer 12 (the area on the surface 12a of the adhesive layer 12 Between the region on the side of the film 13) and the release film 14, the aforementioned voids are likely to occur. That is, the region located near the boundary between the protective film forming film 13 and the adhesive layer 12 and in contact with the release film 14 is likely to have voids.

The composite sheet 1 for forming a protective film shown in FIG. 1 is a state in which the release film 14 is removed, and the back surface of a semiconductor wafer (not shown) is attached to the surface 13a of the film 13 for forming a protective film, and further, The exposed surface on which the protective film forming film 13 is not laminated on the surface 12a of the adhesive layer 12 is attached to a jig such as a ring frame for use.

Fig. 2 is a cross-sectional view schematically showing another embodiment of the composite sheet for forming a protective film of the present invention. In addition, in FIG. 2, the same elements as those shown in FIG. 1 are assigned the same reference numerals as in FIG. 1, and detailed descriptions are omitted. The same is true for the figures below Figure 3.

In the protective film forming composite sheet 2 shown here, a protective film forming film 23 is layered on the entire surface 12a of the adhesive layer 12, and a jig is layered on a part of the surface 23a of the protective film forming film 23 Adhesive layer 15, on the surface 23a of the protective film forming film 23, the exposed surface where the jig adhesive layer 15 is not laminated, and the surface 15a (upper and side) of the jig adhesive layer 15 with a release film laminated 14. In addition, it is the same as the protection shown in Figure 1 The composite sheet 1 for film formation is the same. The adhesive layer 12 in contact with the protective film forming film 23 contains the aforementioned alkyl (meth)acrylate copolymer, and the aforementioned alkyl (meth)acrylate copolymer has a carbon number consisting of an alkyl group constituting the alkyl ester It is a structural unit derived from alkyl (meth)acrylate of 8 or more.

That is, one aspect of the composite sheet for forming a protective film of the present invention includes a substrate, an adhesive layer, a film for forming a protective film, an adhesive layer for a clip, and a release film; the adhesive is laminated on the substrate; The protective film forming film is layered on the entire surface area of the adhesive layer; the jig adhesive layer is laminated on a part of the surface of the protective film forming film; and the protective film forming film is not laminated on the surface The exposed surface of the adhesive layer for jigs and the upper and side surfaces of the adhesive layer for jigs are laminated with the release film; the adhesive layer in contact with the protective film forming film contains the (meth)acrylic acid alkyl A base ester copolymer, and the aforementioned alkyl (meth)acrylate copolymer has a structural unit derived from an alkyl (meth)acrylate whose alkyl group constituting the alkyl ester has a carbon number of 8 or more and 18 or less.

The adhesive layer 15 for jigs may have, for example, a single-layer structure containing an adhesive component, or may have a multiple-layer structure in which layers containing adhesive components are layered on two areas of a sheet as a core material.

In addition, there may be voids between the release film 14 and the surface 23a of the protective film forming film 23 or the surface 15a of the adhesive layer 15 for jigs. For example, the area (area on the side of the protective film forming film 23) on the surface 15a of the jig adhesive layer 15 and the protective film forming film 23 Between the area (area on the side of the adhesive layer 15 for clamps) and the release film 14 shown by the symbol 230a on the surface 23a of, the aforementioned voids are likely to occur.

That is, it is located in the vicinity of the boundary between the adhesive layer 15 for a jig and the film 23 for forming a protective film, and the area|region contacting the peeling film 14 is easy to produce a void part.

The composite sheet 2 for forming a protective film shown in FIG. 2 is a state in which the release film 14 is removed, and the back surface of a semiconductor wafer (not shown) is attached to the surface 23a of the film for forming a protective film 23. Further, The upper surface of the surface 15a of the adhesive layer 15 for jigs is attached to jigs, such as a ring frame, and is used.

Fig. 3 is a cross-sectional view schematically showing another embodiment of the composite sheet for forming a protective film of the present invention.

The composite sheet 3 for forming a protective film shown here is provided with an adhesive layer 32 of a double-layer structure instead of the adhesive layer 12, and the adhesive layer 32 of the aforementioned double-layer structure is sequentially laminated from the base material 11 side with a first adhesive layer 321 and the second adhesive layer 322, except that they are the same as the composite sheet 1 for forming a protective film shown in FIG.

When the composite sheet 3 for forming a protective film is viewed from above, the area of the second adhesive layer 322 is the same as that of the film 13 for forming a protective film, and is arranged such that the peripheral portion overlaps with the film 13 for forming a protective film. The film 13 for forming a protective film is provided on the surface 32a (that is, the surface 322a of the second adhesive layer 322) of the adhesive layer 32 which is the side opposite to the base material side. In addition, the first adhesive layer 321 is provided so as to cover the entire surface 11 a of the base material 11, and the area of the first adhesive layer 321 is larger than the second adhesive layer 322 when viewed from above as described above.

In the protective film forming composite sheet 3, the second adhesive layer 322 in contact with the protective film forming film 13 contains the aforementioned alkyl (meth)acrylate copolymer, and the aforementioned alkyl (meth)acrylate copolymer has A structural unit derived from an alkyl (meth)acrylate having 8 or more carbon atoms in the alkyl group constituting the alkyl ester. In addition, the first adhesive layer 321 that is not in contact with the protective film forming film 13 may contain the aforementioned alkyl (meth)acrylate copolymer or may not contain the aforementioned alkyl (meth)acrylate copolymer.

That is, one aspect of the composite sheet for forming a protective film of the present invention includes a substrate, a first adhesive layer, a second adhesive layer, a film for forming a protective film, an adhesive layer for a jig, and a release film; the first The adhesive layer is provided on the substrate in such a manner as to cover the upper surface of the substrate; the second adhesive layer is provided on the first adhesive layer; the protective film forming film has a peripheral portion and the second adhesive layer The superposition method is provided on the second adhesive layer; the release film is laminated on the upper and side surfaces of the protective film forming film, the side of the second adhesive layer, and the first adhesive layer is not laminated with The surface of the second adhesive layer; when viewed from above and in a plan view, the area of the second adhesive layer is the same as the protective film forming film, and the area of the first adhesive layer is larger than that of the second adhesive Layer; The second adhesive layer contains the alkyl (meth)acrylate copolymer, and the alkyl (meth)acrylate copolymer has the carbon number of the alkyl group constituting the alkyl ester of 8 or more 18 The structural unit derived from alkyl (meth)acrylate.

Fig. 4 schematically shows the composite sheet for forming a protective film of the present invention A cross-sectional view of another embodiment of.

The composite sheet 4 for forming a protective film shown here is provided with an adhesive layer 42 of a two-layer structure instead of the adhesive layer 12, and the adhesive layer 42 of the two-layer structure is laminated in order from the base material 11 side with a first adhesive layer. 421 and the second adhesive layer 422, except that they are the same as the composite sheet 2 for forming a protective film shown in FIG.

When the composite sheet 4 for forming a protective film is viewed from above, the area of any one of the first adhesive layer 421 and the second adhesive layer 422 is the same as that of the film 23 for forming a protective film.

The protective film formation film 23 is provided on the surface 42a of the adhesive layer 42 (that is, the surface 422a of the second adhesive layer 422).

In the protective film forming composite sheet 4, the second adhesive layer 422 in contact with the protective film forming film 23 contains the aforementioned alkyl (meth)acrylate copolymer, and the aforementioned alkyl (meth)acrylate copolymer has A structural unit derived from an alkyl (meth)acrylate having 8 or more carbon atoms in the alkyl group constituting the alkyl ester. In addition, the first adhesive layer 421 that is not in contact with the protective film forming film 23 may contain the aforementioned alkyl (meth)acrylate copolymer or may not contain the aforementioned alkyl (meth)acrylate copolymer.

That is, one aspect of the composite sheet for forming a protective film of the present invention includes a substrate, a first adhesive layer, a second adhesive layer, a film for forming a protective film, an adhesive layer for a jig, and a release film; the first The adhesive layer is laminated on the substrate; the second adhesive layer is laminated on the first adhesive layer; the protective film forming film is laminated on the second adhesive layer; A part of the surface of the protective film forming film is laminated with the adhesive layer for jigs; the exposed surface of the adhesive layer for jigs and the upper surface of the adhesive layer for jigs are not laminated on the surface of the protective film forming film And on the side surface, the release film is laminated; when viewed from above and in a plan view, the area of the first adhesive layer, the second adhesive layer 422, and the protective film forming film 23 are the same; and the protective film The second adhesive layer in contact with the forming film contains the alkyl (meth)acrylate copolymer, and the alkyl (meth)acrylate copolymer has an alkyl group constituting the alkyl ester with a carbon number of 8 Structural units derived from alkyl (meth)acrylates above 18 and below.

The composite sheet for forming a protective film of the present invention is not limited to those shown in FIGS. 1 to 4, and may be a composite sheet for forming a protective film shown in FIGS. 1 to 4 within a range that does not impair the effects of the present invention. Part of the composition of the sheet is changed or deleted, or the composite sheet for forming a protective film described above is further added with another composition.

For example, in the composite sheet 3 for forming a protective film shown in FIG. 3, when the composite sheet 3 for forming a protective film is viewed from above, the area of the second adhesive layer 322 is the same as that of the film 13 for forming a protective film. And is smaller than the area of the first adhesive layer 321, but the area of the second adhesive layer 322 may be different from that of the protective film forming film 13, for example, it may be larger than the area of the protective film forming film 13. In this case, the second adhesive layer The area of the agent layer 322 may be the same as that of the first adhesive layer 321.

In addition, the composite sheet 3 for forming a protective film shown in FIG. 3 and shown in FIG. 4 In the composite sheet 4 for forming a protective film, the adhesive layer has a two-layer structure, but the adhesive layer may also have a laminated structure of three or more layers. At this time, among the three or more adhesive layers, the layer in contact with the protective film forming film (that is, the uppermost layer farthest from the substrate in the thickness direction of the adhesive layer) contains the aforementioned (meth)acrylic alkyl group The other layer may contain the aforementioned alkyl (meth)acrylate copolymer or not contain the aforementioned alkyl (meth)acrylate copolymer.

As described in the following examples, for the aforementioned composite sheet for forming a protective film with a size of 25mm×150mm, the adhesive layer before curing is subjected to the conditions of a peeling angle of 180°, a temperature of 23°C, and a stretching speed of 300mm/min The peeling force measured in the form of the load when peeling off the protective film (hereinafter, sometimes referred to as "peel force before hardening of the adhesive layer") is preferably 2000 mN/25mm or more, more preferably 2200 mN/25mm or more.

Similarly, as described in the following examples, for the aforementioned composite sheet for forming a protective film with a size of 25mm×150mm, the cured adhesive layer was peeled at a peeling angle of 180°, a temperature of 23°C, and a stretching speed of 300mm/ The condition of min. The peeling force measured from the form of the load when the protective film is peeled off (hereinafter, sometimes referred to as the "peel force after curing of the adhesive layer") is preferably 2000mN/25mm or less, for example, 1700mN/25mm Below, 1200mN/25mm or less, 700mN/25mm or less, etc.

In the present invention, regarding the composite sheet for forming a protective film with the size of 25mm×150mm, the peeling force of the adhesive layer before curing is relative to that of the adhesive The ratio of the peeling force after the adhesion and curing ([the peeling force before the adhesive layer is cured]/[the peeling force after the adhesive layer is cured]) is preferably 1.5 or more, for example, 3 or more, 6 or more, 12 or more.

<Method for manufacturing composite sheet for forming protective film>

The composite sheet for forming a protective film of the present invention can be manufactured by, for example, forming an adhesive layer from the adhesive composition on a substrate, and forming a protective film on the adhesive layer with the composition for forming a protective film. Film for film formation.

The adhesive layer can be formed by applying an adhesive composition to the surface of the substrate (the surface 11a of the substrate 11 in FIGS. 1 and 2) and drying it. At this time, if necessary, the applied adhesive composition can be heated to generate crosslinking. The heating condition is preferably 100°C to 130°C for 1 minute to 5 minutes, but is not limited to this. In addition, the adhesive layer can also be formed by the following method: the adhesive composition is applied to the surface of the release layer of the release material and dried to attach the adhesive layer to the surface of the substrate, and then the release material is removed .

The adhesive composition may be applied to the surface of the substrate or the surface of the release layer of the release material by a known method. For example, methods using the following various coaters: air knife coater, knife coater, Bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Meyer bar coater , Contact Coating machine etc.

The protective film formation film can be formed from the protective film formation composition by the same method as the adhesive layer formed on the substrate as described above, but it is generally difficult to directly coat the protective film formation composition on the adhesive layer. Therefore, it is preferable to first form a protective film forming film by another method and attach the protective film forming film to the surface of the adhesive layer. For example, apply the protective film forming composition to the surface of the release layer of the release material The protective film forming film formed by drying the product is attached to the surface of the adhesive layer, and then the aforementioned peeling material is removed.

In addition to the above method, the composite sheet for forming a protective film of the present invention can also be formed by, for example, forming an adhesive layer from the adhesive composition, and forming a protective film from the composition for forming a protective film. After using the film, the adhesive layer and the protective film forming film are overlapped to form a laminate, and the laminate is pasted on the surface of the adhesive layer (the surface of the adhesive layer on which the protective film forming film is not provided)合 substrate.

At this time, the formation conditions of the adhesive layer and the protective film formation film are the same as the above-mentioned method.

For example, when manufacturing a composite sheet for forming a protective film as shown in FIG. 1, when looking down from above and looking down on a composite sheet for forming a protective film, the surface area of the film for forming a protective film is smaller than that of the adhesive layer, and then manufacturing as described above In the method, as long as the protective film forming film is cut into a specific size and shape in advance, Just put it on the adhesive layer.

<How to use the composite sheet for forming a protective film>

The method of using the composite sheet for forming a protective film of the present invention is as follows.

That is, first, the back surface of the semiconductor wafer is attached to the protective film formation film of the protective film formation composite sheet, and the protective film formation composite sheet is fixed to the dicing device.

Next, the protective film is formed by heating (for example, heating at 130°C for 2 hours) to harden the protective film. When a back polishing tape is attached to the surface (electrode formation surface) of a semiconductor wafer, the back polishing tape is usually removed from the semiconductor wafer to form a protective film.

Next, the semiconductor wafer is cut to form a semiconductor wafer. After the protective film is formed until the cutting is performed, the protective film may be irradiated with a laser beam from the base material side of the protective film forming composite sheet, and printing may be performed on the surface of the protective film. At this time, as explained above, since the peeling force between the adhesive layer and the protective film before curing is sufficiently large, even if gas is generated by laser printing, the peeling of the adhesive layer and the protective film is suppressed, and gas is generated The accumulation is suppressed. In addition, since the semiconductor wafer can be firmly and stably fixed to the composite sheet for forming a protective film, splashing of the wafer during dicing is suppressed, and dicing can be performed stably. Furthermore, in the case of laser printing, since the peeling of the adhesive layer and the protective film is suppressed as described above, and the generation of air volume is also suppressed, the substrate and the adhesive layer are interposed The printing applied on the protective film can be clearly recognized visually.

Then, the adhesive layer is cured by irradiating active energy rays (for example, ultraviolet rays, electron beams, etc.), and the cured adhesive layer is peeled off the semiconductor chip together with the protective film attached to the back of the semiconductor chip and picked up , Thereby obtaining a semiconductor chip with a protective film. At this time, since the peeling force between the cured adhesive layer and the protective film is sufficiently small, the semiconductor wafer with the protective film can be picked up stably and easily, and the chip cracks or chipping during pickup can be suppressed.

For example, when using the protective film forming composite sheet 1 shown in FIG. 1, the back surface of the semiconductor wafer is attached to the protective film forming film 13 of the protective film forming composite sheet 1, and the exposed adhesive layer 12 is attached Attach it to a cutting jig (not shown) such as a ring frame, and fix the protective film forming composite sheet 1 in the cutting device. Next, after curing the protective film forming film 13 to form a protective film, it is cut, and then the area of the adhesive layer 12 except the part attached to the jig is cured by irradiating active energy rays, and the pick-up is protected. Film semiconductor wafers are sufficient. In this way, when using the composite sheet 1 for forming a protective film, it is necessary to adjust so that the specific area of the adhesive layer 12 does not harden to prevent the composite sheet 1 for forming a protective film from peeling off the jig. On the other hand, when the composite sheet 1 for forming a protective film is used, it is not necessary to separately provide a structure for attaching the composite sheet 1 for forming a protective film to the jig.

On the other hand, when the composite sheet 2 for forming a protective film shown in FIG. 2 is used, The back surface of the semiconductor wafer is attached to the protective film forming film 23 of the protective film forming composite sheet 2, and the jig adhesive layer 15 is attached to a dicing jig (not shown) such as a ring frame to protect The composite sheet 2 for film formation is fixed in a cutting device. Next, after curing the protective film forming film 23 to form a protective film, dicing is performed, and the adhesive layer 12 is cured by irradiating active energy rays to pick up the semiconductor wafer with the protective film. In this way, when the composite sheet 2 for forming a protective film is used, unlike when the composite sheet 1 for forming a protective film is used, it is not necessary to adjust so that the specific area of the adhesive layer 23 does not harden. On the other hand, unlike the composite sheet 1 for forming a protective film, the composite sheet 2 for forming a protective film must be provided with an adhesive layer 15 for a jig. By providing the adhesive layer 15 for jigs, the adhesive layer 12 can be selected from a wide range of composition layers according to the purpose.

As described above, the composite sheet for forming a protective film of the present invention is suitable for the case of curing the adhesive layer after curing the protective film forming film to form the protective film, and when cutting and picking up semiconductor wafers , The protective film forming film is completely or almost completely cured. In addition, the composite sheet for forming a protective film of the present invention exerts the effect that the peeling force between the adhesive layer and the protective film changes significantly before and after the adhesive layer is cured. This effect is caused by the adhesive layer containing the alkyl (meth)acrylate copolymer in a specific range as an essential component.

On the other hand, for example, the conventional composite sheet for forming a protective film described in the document "Japanese Patent Application Laid-Open No. 2011-228450" (Patent Document 1) described above, when picking up a semiconductor wafer, a film for forming a protective film When stopping in the uncured or partially cured state, the semiconductor wafer is bonded and the sealing material is cured, and the uncured or partially cured protective film forming film is completely or substantially cured. That is, when the conventional composite sheet for forming a protective film is used, the characteristics of the film attached to the wafer and the back surface of the wafer during the dicing of the semiconductor wafer and the pickup of the semiconductor wafer are the same as those of the present invention. The membrane is completely different. In addition, in this document, there is no disclosure about the composition of the adhesive layer and the protective film formation film suitable for curing the protective film formation film before cutting.

Another aspect of the composite sheet for forming a protective film of the present invention includes a substrate, an adhesive layer, and a film for forming a protective film; the adhesive is laminated on the substrate, and the film for forming a protective film is laminated on the adhesive On the layer; the adhesive layer has active energy ray curability, and at least the layer in contact with the protective film formation film contains (meth)acrylic acid alkyl ester copolymer; the aforementioned (meth)acrylic acid alkyl ester copolymer The material is a copolymer having structural units derived from alkyl (meth)acrylates with a carbon number of 8 or more and 18 or less that constitute the alkyl group of the alkyl ester; the film for forming the protective film has thermosetting properties; After the composite sheet for film formation was cut into a size of 25mm×150mm, it was attached to a silicon wafer at 70°C, and then the composite sheet for protective film formation was heated at 130°C for 2 hours to make the film for protective film formation When curing to form a protective film, under the conditions of a peeling angle of 180°, a measuring temperature of 23°C, and a stretching speed of 300mm/min, the peeling force of the adhesive layer and the protective film before curing (the peeling force of the adhesive layer before curing) ) Is 2000mN/25mm or more, preferably 2300mN/25mm or more and 6300mN/25mm or less.

Furthermore, regarding the composite sheet for forming a protective film, when the composite sheet for forming a protective film is irradiated with ultraviolet rays under conditions of an illuminance of 220 mW/cm ² and a light quantity of 190 mJ/cm ^{2 to} harden the adhesive layer, the peeling angle is 180° , Under the conditions of measuring temperature 23℃ and stretching speed 300mm/min, the peeling force of the adhesive layer and the protective film after curing (the peeling force of the adhesive layer after curing) is below 2000mN/25mm, preferably 500mN /25mm or more, 1500mN/25mm or less.

Another aspect of the composite sheet for forming a protective film of the present invention includes a substrate, an adhesive layer, and a film for forming a protective film; the adhesive is laminated on the substrate, and the film for forming a protective film is laminated on the adhesive On the layer; the adhesive layer has active energy ray curability, and at least the layer in contact with the protective film forming film contains an alkyl (meth)acrylate copolymer, and the alkyl (meth)acrylate copolymer contains Alkyl (meth)acrylate copolymer, isocyanate-based crosslinking agent, photopolymerization initiator, solvent, and other components as necessary; the aforementioned alkyl (meth)acrylate copolymer is composed of alkyl ester A copolymer of structural units derived from alkyl (meth)acrylate whose alkyl group has a carbon number of 8 or more and 18 or less, preferably selected from the group consisting of 2-ethylhexyl acrylate, lauryl methacrylate and isoacrylate At least one of the group consisting of stearyl esters; the content of the structural unit derived from the alkyl (meth)acrylate having 8 or more carbon atoms in the aforementioned alkyl group is relative to that of the aforementioned alkyl (meth)acrylate The total mass of all structural units of the base ester copolymer is 30% by mass to 100% by mass, preferably 35% to 85% by mass, more preferably 40% to 80% by mass; the aforementioned protective film is formed The film has thermosetting properties and contains a polymer component (A), a thermosetting component (B), a hardening accelerator (C), and if necessary, selected from solvents, fillers (D), coupling agents (E), At least one of the crosslinking agent (F) and general additives (G); the polymer component (A) is preferably selected from acrylic resins, polyesters, polyurethanes, and acrylic amines At least one of the group consisting of formate resin, silicone resin, rubber-based polymer, and phenoxy resin is more preferably an acrylic polymer; the thermosetting component (B) is preferably a ring Oxygen resin (B11) and thermosetting agent (B12), more preferably selected from polyfunctional epoxy resin, biphenyl compound, bisphenol A diglycidyl ether and its hydride, o-cresol novolac epoxy resin, Dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin, and epoxy compounds with more than two functions At least one of the group consisting of, and at least one selected from the group consisting of onium salt, dibasic acid hydrazine, dicyandiamine, and amine adduct of hardener, and more preferably At least one selected from the group consisting of bisphenol A type epoxy resin and dicyclopentadiene type epoxy resin, and dicyandiamine; the hardening accelerator (C) is preferably 2-phenyl -4,5-Dimethylolimidazole; The composite sheet for forming the protective film is cut into a size of 25mm×150mm, and then attached to the silicon wafer at 70°C, and then the composite sheet for forming the protective film is When heating at 130°C for 2 hours to harden the protective film forming film to form a protective film, under the conditions of a peeling angle of 180°, a measuring temperature of 23°C, and a stretching speed of 300mm/min, the adhesive layer before curing The peeling force of the aforementioned protective film (peeling force before the adhesive layer is cured) is 2000 mN/25mm or more, preferably 2300 mN/25mm or more and 6300 mN/25mm or less.

Furthermore, regarding the composite sheet for forming a protective film, when the composite sheet for forming a protective film is irradiated with ultraviolet rays under conditions of an illuminance of 220 mW/cm ² and a light quantity of 190 mJ/cm ^{2 to} harden the adhesive layer, the peeling angle is 180° , Under the conditions of measuring temperature 23℃ and stretching speed 300mm/min, the peeling force of the adhesive layer and the protective film after curing (the peeling force of the adhesive layer after curing) is below 2000mN/25mm, preferably 500mN /25mm or more, 1500mN/25mm or less.

Another aspect of the present invention is a use of the composite sheet for forming a protective film as described above for manufacturing a semiconductor wafer with a protective film; the composite sheet for forming a protective film includes a substrate, an adhesive layer, and a protective film for forming The adhesive layer is laminated on the substrate, the protective film forming film is laminated on the adhesive layer; the adhesive layer has active energy ray curability, and is at least in contact with the protective film forming film The layer contains an alkyl (meth)acrylate copolymer; the aforementioned alkyl (meth)acrylate copolymer has an alkyl (meth)acrylate with a carbon number of 8 or more and 18 or less that constitutes the alkyl group of the alkyl ester A copolymer of structural units derived from base ester; the aforementioned protective film formation film has thermosetting properties; the aforementioned protective film formation composite sheet is cut into a size of 25mm×150mm and then attached to a silicon wafer at 70°C, Next, heat the composite sheet for forming a protective film at 130°C for 2 hours to harden the film for forming a protective film to form a protective film, under the conditions of a peeling angle of 180°, a measurement temperature of 23°C, and a stretching speed of 300 mm/min Next, the peeling force of the adhesive layer and the protective film before curing (the peeling force of the adhesive layer before curing) is 2000mN/25mm or more, preferably 2300mN/25mm or more , Below 6300mN/25mm.

Furthermore, regarding the composite sheet for forming a protective film, when the composite sheet for forming a protective film is irradiated with ultraviolet rays under conditions of an illuminance of 220 mW/cm ² and a light quantity of 190 mJ/cm ^{2 to} harden the adhesive layer, the peeling angle is 180° , Under the conditions of measuring temperature 23℃ and stretching speed 300mm/min, the peeling force of the adhesive layer and the protective film after curing (the peeling force of the adhesive layer after curing) is below 2000mN/25mm, preferably 500mN /25mm or more, 1500mN/25mm or less.

A method for manufacturing a semiconductor wafer with a protective film, the manufacturing method comprising the steps of: attaching a composite sheet for forming a protective film to the back of the semiconductor wafer by a film for forming a protective film; and attaching the foregoing by heating In the composite sheet for forming a protective film, the protective film forming film is cured to form a protective film; the semiconductor wafer on which the protective film is formed is cut to form a semiconductor chip; and the protective film is formed by irradiating active energy rays The adhesive layer in the composite sheet is hardened, and then the semiconductor chip is picked up together with the protective film attached to the back of the semiconductor chip; and the protective film forming composite sheet includes a substrate, the adhesive layer, and The protective film formation film, the adhesive layer is laminated on the substrate, the protective film formation film is laminated on the adhesive layer; the adhesive layer has active energy ray curability, and is at least compatible with the protective film The layer in contact with the forming film contains an alkyl (meth)acrylate copolymer; the aforementioned alkyl (meth)acrylate copolymer has a carbon number of 8 or more and 18 or less ( Structural unit derived from alkyl meth)acrylate Yuan copolymer; the aforementioned protective film formation film has thermosetting properties.

[Example]

Hereinafter, the present invention will be explained in more detail with specific examples. However, the present invention is not limited at all by the examples shown below.

[Example 1]

<Production of composite sheet for protective film formation>

A composite sheet for forming a protective film having the configuration shown in Fig. 1 was produced. More specifically, it is as follows.

[Manufacturing of Support Sheet (Formation of Adhesive Layer)]

The adhesive composition was coated on one surface of a polypropylene film (thickness 80 μm, manufactured by Mitsubishi Plastics Corporation) as a base material and dried to form an ultraviolet-curable adhesive layer (thickness 10 μm) to obtain a support sheet. The aforementioned adhesive composition is the following composition: containing 100 parts by mass of an alkyl (meth)acrylate copolymer (solid content), a trifunctional xylylene diisocyanate crosslinking agent (Mitsui Takeda Chemicals, Inc. The manufactured "Takenate D110N") 6.6 parts by mass (solid content) and the photopolymerization initiator ("Irgacure 127" manufactured by BASF) 3.0 parts by mass (solid content), and methyl ethyl ketone and toluene are used The mixed solvent of ethyl acetate and the solid content is adjusted to 30% by mass. In addition, the aforementioned (meth)acrylic acid alkyl ester copolymer is an ultraviolet curable acrylic copolymer with a weight average molecular weight of 1.100000 obtained by the following method: Acrylic acid-2-ethylhexyl A pre-copolymer obtained by copolymerizing 80 parts by mass of ester (hereinafter sometimes referred to as "2EHA") and 20 parts by mass of 2-hydroxyethyl acrylate (hereinafter sometimes referred to as "HEA"), and further with 2- Methacryloxyethyl isocyanate (-2-isocyanoxyethyl methacrylate, hereinafter sometimes referred to as "MOI") 21.4 parts by mass (in 2-methacryloxyethyl isocyanate The total molar number of isocyanate groups is 0.8 times the total molar number of hydroxyl groups in the HEA) for the reaction. Table 1 shows the blending amounts of monomer components when producing the alkyl (meth)acrylate copolymer. In addition, in Table 1, the column of the monomer component is described as "-", which means that the monomer component is not formulated.

[Manufacturing of composite sheet for protective film formation (formation of protective film formation film)]

Coat the peeling treatment surface of the peeling film ("SP-PET381031" made by Lintec Corporation, thickness 38μm) after peeling off one side of the polyethylene terephthalate film by silicone treatment The protective film formation composition was dried to form a protective film formation film (thickness 25 μm). The composition for forming the protective film is the following composition: the following components are blended in the amounts shown in Table 2 (solid content), and the solids are prepared using a mixed solvent of methyl ethyl ketone, toluene and ethyl acetate The component concentration is adjusted to 55% by mass.

Next, the protective film formation film is bonded to the surface of the adhesive layer of the support sheet obtained in the above, thereby obtaining a protective film formation composite sheet, which is applied to the protective film formation film The surface on the side opposite to the side where the adhesive layer is provided is provided with the aforementioned release film.

(Polymer component (A))

(A)-1: An acrylic polymer obtained by copolymerizing 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight 370,000, glass transition temperature 6°C)

(Thermosetting component (B))

‧Epoxy resin (B11)

(B11)-1: Bisphenol A epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 184g/eq to 194g/eq)

(B11)-2: Bisphenol A epoxy resin ("jER1055" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 800g/eq to 900g/eq)

(B11)-3: Dicyclopentadiene epoxy resin ("Epiclon HP-7200HH" manufactured by DIC, epoxy equivalent 255g/eq to 260g/eq)

‧Thermal hardener (B12)

(B12)-1: Dicyandiamide (solid dispersion type latent hardener, "Adeka Hardener EH-3636AS" manufactured by ADEKA, active hydrogen content 21g/eq)

(Hardening accelerator (C))

(C)-1: 2-Phenyl-4,5-Dihydroxymethylimidazole ("Curezol 2PHZ" manufactured by Shikoku Chemical Industry Co., Ltd.)

(Filling material (D))

(D)-1: Silica filler ("SC2050MA" from Admatechs, average particle size 0.5μm)

(Coupling agent (E))

(E)-1: Silane coupling agent ("A-1110" manufactured by Japan Uny)

(General additives (G))

(G)-1: Carbon black (colorant, "#MA650" manufactured by Mitsubishi Chemical Corporation, average particle size 28nm)

<Evaluation of composite sheet for forming protective film>

[Suppression of chip splash during cutting]

After removing the release film from the protective film forming composite sheet obtained above, the exposed protective film forming film was attached to the dry polishing surface of a silicon wafer (diameter 6 inches, thickness 100 μm) at 70°C, and The exposed adhesive layer is attached to the ring frame and left for 30 minutes.

Next, the composite sheet for forming a protective film was heated at 130° C. for 2 hours to harden the film for forming a protective film to form a protective film.

Then, using a cutting device, the silicon wafer is cut into a size of 5mm×5mm to obtain a wafer. At this time, visually confirm whether there is chip spatter, and evaluate the case where there is no chip splash as "A", and the case where there is more than one chip splash as "B". The results are shown in Table 3.

[Pickup]

After removing the release film from the protective film forming composite sheet obtained above, the exposed protective film forming film was attached to the dry polishing surface of a silicon wafer (diameter 6 inches, thickness 100 μm) at 70°C, and Attach the exposed adhesive layer to the ring frame and let it stand for 30 minutes.

Next, the composite sheet for forming a protective film was heated at 130°C for 2 hours to make The protective film formation film is cured to form a protective film.

Then, using a cutting device, the silicon wafer is cut into a size of 5mm×5mm to obtain a wafer. Then, using an ultraviolet irradiation device (“RAD2000m/8” manufactured by Lintec Corporation), with an illuminance of 220mW/cm ² and a light quantity of 190mJ/cm ² , a high-pressure mercury lamp was used as a light source to irradiate the protective film forming composite sheet from the substrate side The ultraviolet rays harden the adhesive layer.

Then, use a die bonder ("BESTEM-D02" manufactured by Canon Machinery Inc.) to pick up 20 chips, and evaluate the situation where no chip has cracks or nicks as "A", and there will be more than one chip with cracks or The situation of the gap is evaluated as "B". The results are shown in Table 3.

[Peeling force of adhesive layer and protective film before curing]

After cutting the composite sheet for forming a protective film obtained above into a size of 25mm×150mm, remove the release film, and use a laminator ("LAMIPACKER LPD3214" manufactured by Fuji) to expose the exposed film for forming a protective film Attach it to the dry polished surface of a silicon wafer (6 inches in diameter and 500 μm thick) at 70°C.

Next, the composite sheet for forming a protective film was heated at 130°C for 2 hours to harden the film for forming a protective film to form a protective film, and a test piece (1) was produced.

For this test piece (1), a precision universal testing machine (Autograph AG-IS manufactured by Shimadzu Corporation) was used to perform a tensile test under the conditions of a peeling angle of 180°, a measurement temperature of 23°C, and a tensile speed of 300 mm/min. The support sheet (the laminate of the adhesive layer and the base material before curing) peels off from the protective film, and the load at this time is measured as the peeling force of the adhesive layer and the protective film before curing (Peeling force of the adhesive layer before curing). In addition, as the measured value of the aforementioned load, among the measured values when the support sheet was peeled off with a length of 100 mm, the values at the initial peel length of 10 mm and the final peeled length of 10 mm were excluded from the effective values.

The results are shown in Table 3. The value of "Before Adhesive Layer Hardening" in the "Peeling Force (mN/25mm)" column in Table 3 is the corresponding result.

[Peeling force of adhesive layer and protective film after curing]

Make the same test piece as above (1).

Next, using an ultraviolet irradiation device (“RAD2000m/8” manufactured by Lintec Corporation), with an illuminance of 220mW/cm ² and a light quantity of 190mJ/cm ² , a high-pressure mercury lamp was used as a light source to irradiate the protective film forming composite sheet from the substrate side Ultraviolet rays harden the adhesive layer to prepare a test piece (2).

The test piece (2) was subjected to a tensile test in the same manner as the above-mentioned test piece (1), that is, the support sheet (the laminate of the cured adhesive layer and the base material) was peeled from the protective film as the cured The peeling force of the adhesive layer and the protective film (the peeling force of the adhesive layer after curing). The results are shown in Table 3. The value of "After the adhesive layer is hardened" in the column of "Peeling Force (mN/25mm)" in Table 3 is the corresponding result.

<Production and Evaluation of Composite Sheets for Forming Protective Films>

[Example 2]

When forming the adhesive layer, use an ultraviolet curable acrylic copolymer with a weight average molecular weight of 500,000 instead of the above weight average molecular weight 1.100000 was used as an alkyl (meth)acrylate copolymer, except that the same method as in Example 1 was used to produce and evaluate a composite sheet for forming a protective film. Among them, the ultraviolet curable acrylic with a weight average molecular weight of 500,000 The copolymer was obtained in the following manner: as shown in Table 1, a prepolymer obtained by copolymerizing 40 parts by mass of 2EHA, 40 parts by mass of vinyl acetate (hereinafter, sometimes referred to as "VAc"), and 20 parts by mass of HEA The copolymer was further reacted with 21.4 parts by mass of MOI (the total number of moles of isocyanate groups in MOI is 0.8 times the total number of moles of hydroxyl groups in HEA). The results are shown in Table 3.

[Example 3]

When forming the adhesive layer, a UV curable acrylic copolymer with a weight average molecular weight of 600,000 was used instead of the above-mentioned weight average molecular weight of 1.100000 as the alkyl (meth)acrylate copolymer, except that it was the same as in Example 1. The method of manufacturing and evaluating a composite sheet for forming a protective film, wherein the ultraviolet curable acrylic copolymer with a weight average molecular weight of 600,000 is obtained as follows: as shown in Table 1, lauryl methacrylate (hereinafter, there are (Hereinafter referred to as "LMA") 80 parts by mass and 20 parts by mass of HEA are copolymerized to obtain a pre-copolymer, and 21.4 parts by mass of MOI (the total molar number of isocyanate groups in MOI is the total molar number of hydroxyl groups in HEA). 0.8 times the number of ears) for the reaction. The results are shown in Table 3.

[Example 4]

When forming the adhesive layer, use an ultraviolet curable acrylic copolymer with a weight average molecular weight of 600,000 instead of the above weight average molecular weight 1.100000 was used as an alkyl (meth)acrylate copolymer, except that the composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1. Among them, the ultraviolet curable acrylic type with a weight average molecular weight of 600,000 The copolymer was obtained as follows: as shown in Table 1, a pre-copolymer obtained by copolymerizing 80 parts by mass of isostearyl acrylate (hereinafter, referred to as "ISTA") and 20 parts by mass of HEA , And further reacted with MOI 21.4 parts by mass (the total molar number of isocyanate groups in MOI is 0.8 times the total molar number of hydroxyl groups in HEA). The results are shown in Table 3.

[Comparative Example 1]

When forming the adhesive layer, a UV curable acrylic copolymer with a weight average molecular weight of 600,000 was used instead of the above-mentioned weight average molecular weight of 1.100000 as the alkyl (meth)acrylate copolymer, except that it was the same as in Example 1. The method of manufacturing and evaluating a composite sheet for forming a protective film, wherein the ultraviolet curable acrylic copolymer with a weight average molecular weight of 600,000 is obtained as follows: as shown in Table 1, butyl acrylate (hereinafter, sometimes referred to as It is a pre-copolymer obtained by copolymerizing 40 parts by mass of "BA"), 40 parts by mass of VAc, and 20 parts by mass of HEA, and 21.4 parts by mass of MOI (the total molar number of isocyanate groups in MOI is the hydroxyl group in HEA 0.8 times the total number of moles) for the reaction. The results are shown in Table 3.

[Comparative Example 2]

When forming the adhesive layer, use an ultraviolet curable acrylic copolymer with a weight average molecular weight of 600,000 instead of the above weight average molecular weight 1.100000 was used as an alkyl (meth)acrylate copolymer, except that the composite sheet for forming a protective film was produced and evaluated in the same manner as in Example 1. Among them, the ultraviolet curable acrylic type with a weight average molecular weight of 600,000 The copolymer was obtained as follows: as shown in Table 1, 40 parts by mass of BA, 40 parts by mass of methyl methacrylate (hereinafter, sometimes referred to as "MMA"), and 20 parts by mass of HEA were copolymerized. The pre-copolymer is further reacted with MOI 21.4 parts by mass (the total molar number of isocyanate groups in MOI is 0.8 times the total molar number of hydroxyl groups in HEA). The results are shown in Table 3.

[Table 2]

When using the composite sheet for forming a protective film of Examples 1 to 4, in the sheet, the alkyl (meth)acrylate copolymer has a carbon number of 8 or more (former (Base) a structural unit derived from alkyl acrylate, whereby the peeling force between the adhesive layer and the protective film before curing is sufficiently large, It can be diced stably, and the peeling force between the cured adhesive layer and the protective film is small enough to pick up semiconductor wafers stably.

Regarding the ratio of the peeling force before and after curing of the adhesive layer ([Peeling force before adhesive layer hardening]/[Peeling force after adhesive layer hardening]), it was 4.6 in Example 1, 4.2 in Example 2, and Example 3 Medium is 14.3, Example 4 is 1.8, Examples 1 to 3 are particularly large, and Example 3 is significantly larger, suggesting that when the carbon number of the alkyl group constituting the aforementioned alkyl ester is about 12 and 12 When the value is higher, the effect of the present invention is particularly high.

In contrast, when the composite sheet for forming a protective film of Comparative Examples 1 to 2 is used, in the sheet, the alkyl (meth)acrylate copolymer does not have the carbon number of the alkyl group constituting the alkyl ester. 8 or more structural units derived from alkyl (meth)acrylates, whereby the peeling force between the adhesive layer and the protective film before curing is large enough for stable cutting, but the adhesive layer and protective film after curing The peeling force has not become small enough to pick up semiconductor wafers stably.

(Industrial availability)

The present invention can be used to manufacture semiconductor chips whose back surface is protected by a protective film, etc., and therefore is extremely useful in industry.

1: Composite sheet for protective film formation

10: Support film

11: Substrate

11a: The surface of the substrate

12: Adhesive layer

12a: The surface of the adhesive layer

120a: Area on the side of the protective film formation film

13: Film for forming protective film

13a: Surface of protective film formation film

130a: Area on the side of the adhesive layer

14: peeling film

Claims (6)

A composite sheet for forming a protective film is provided with an adhesive layer on a substrate, a protective film forming film is provided on the adhesive layer, the adhesive layer has active energy ray curability, and the protective film forming film has heat Curability: The composite sheet for forming a protective film is used to manufacture a semiconductor chip with a protective film. After the composite sheet for forming a protective film is attached to the back surface of the semiconductor wafer by the protective film forming film, it is heated The protective film forming film is cured as a protective film, the semiconductor wafer is then cut to form a semiconductor chip, the adhesive layer is cured by irradiating active energy rays, and then the semiconductor chip is attached to the semiconductor The protective film on the back of the wafer is picked up together to manufacture a semiconductor chip with a protective film; the adhesive layer contains an alkyl (meth)acrylate copolymer in at least the layer in contact with the protective film forming film; The aforementioned alkyl (meth)acrylate copolymer has a structural unit derived from an alkyl (meth)acrylate having an alkyl group of 8 or more carbon atoms; in the composite sheet for forming a protective film, The protective film is formed by heating the protective film forming film at 130°C for 2 hours to form a protective film. The adhesive layer before curing is self-protected under the conditions of a peeling angle of 180°, a temperature of 23°C, and a stretching speed of 300mm/min. The peeling force before curing of the adhesive layer at the time of film peeling is 2000mN/25mm or more. In the composite sheet for forming a protective film, the protective film is cured by heating the film for forming a protective film at 130°C for 2 hours to form a protective film. Under the conditions of illuminance 220mW/cm ² and light quantity 190mJ/cm ² , the adhesive layer is irradiated with ultraviolet rays to harden the adhesive layer, and the cured adhesive layer is stretched at a peeling angle of 180°, a temperature of 23°C, and The peeling force after curing of the adhesive layer when peeling from the protective film at a speed of 300mm/min is 2000mN/25mm or more, and the ratio of the peeling force before curing of the adhesive layer to the peeling force after curing of the adhesive layer is 1.5 or more. The composite sheet for forming a protective film according to claim 1, wherein the film for forming a protective film contains an epoxy resin, a thermosetting agent, and imidazoles, and the thermosetting agent is dissolved by heating and hardens the epoxy resin active. The composite sheet for forming a protective film as described in claim 1 or 2, wherein the number of carbon atoms in the alkyl group constituting the alkyl ester is 11 to 18. The composite sheet for forming a protective film according to claim 1 or 2, wherein the film for forming the protective film contains acrylic resin, epoxy resin, and a thermosetting agent, and the monomer constituting the acrylic resin is: The alkyl group of the base ester is a chain-like alkyl (meth)acrylate with a carbon number of 1 to 18, and a hydroxyl-containing (meth)acrylate; the aforementioned thermosetting agent is a curing agent for the aforementioned epoxy resin; In the film for forming a protective film, when the content of the acrylic resin is 100 parts by mass, the total content of the epoxy resin and the thermosetting agent is 1 part by mass to 100 parts by mass. The composite sheet for forming a protective film as described in claim 1 or 2, wherein the adhesive layer contains 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanyl)- Benzyl]phenyl}-2-methyl-propan-1-one is used as a photopolymerization initiator. A method for manufacturing a semiconductor chip with a protective film, which uses the composite sheet for forming a protective film as described in any one of claims 1 to 5 to manufacture a semiconductor chip with a protective film; formed by the aforementioned protective film After the composite sheet for forming a protective film is attached to the back surface of a semiconductor wafer with a film, the film for forming a protective film is cured by heating to form a protective film, and then the semiconductor wafer is cut to form a semiconductor wafer. Active energy rays are irradiated to harden the adhesive layer, and then the semiconductor chip is picked up together with the protective film attached to the back surface of the semiconductor chip, thereby obtaining a semiconductor chip with a protective film.

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