JP6334197B2 - Composite sheet for forming protective film, chip with protective film, and method for manufacturing chip with protective film - Google Patents

Description

  The present invention is capable of forming a protective film on the back surface of a workpiece such as a semiconductor wafer or semiconductor chip, and capable of improving the manufacturing efficiency of the semiconductor chip, and forming the protective film of the composite sheet on the back surface of the semiconductor chip. The present invention relates to a chip with a protective film having a protective film formed by curing a film for use, and a method for producing a chip with a protective film.

  In recent years, semiconductor devices have been manufactured using a so-called face-down mounting method. In the face-down method, a semiconductor chip (hereinafter simply referred to as “chip”) having electrodes such as bumps on a circuit surface is used, and the electrodes are bonded to a substrate. For this reason, the surface (chip back surface) opposite to the circuit surface of the chip may be exposed.

  The exposed back surface of the chip is protected by a protective film made of an organic material and may be taken into the semiconductor device as a chip with a protective film. In general, this chip with a protective film is formed by applying a liquid resin to the back surface of the wafer by spin coating or the like to form a coating film, and drying and curing the coating film to form a protective film on the back surface of the wafer. It can be obtained by cutting the protective film together with the wafer.

However, the above-described chip manufacturing method increases the number of processes and increases the product cost.
In addition, since the thickness of the protective film formed from a liquid resin in this way is not sufficient, there is often a problem of a decrease in the yield of the resulting chip with the protective film.

  As means for solving the above problems, Patent Document 1 discloses a chip protection film having a release sheet, and a protective film forming layer comprising an energy ray curable component and a binder polymer component formed on the release sheet. Is disclosed.

Now that semiconductor chips are becoming thinner and more dense, even when exposed to harsh temperature conditions, semiconductor devices equipped with chips with protective films are required to have higher reliability. Has been.
According to the study by the present inventors, the chip protective film described in Patent Document 1 may shrink when the protective film forming layer is cured, which may cause a problem that the semiconductor wafer is warped. In particular, in the case of an ultra-thin semiconductor wafer, the above problem is remarkably generated. If the semiconductor wafer is warped, the wafer may be damaged or the marking (printing) accuracy on the protective film may be reduced.

In order to solve such a problem, the present applicant has, in Patent Document 2, a substantially circular region composed of a protective film forming layer and an annular region composed of a re-peeling adhesive surrounding the region on the upper surface. A sheet for protective film formation and dicing consisting of a sheet is proposed.
If a semiconductor wafer is placed on the protective film forming layer of the protective film forming and dicing sheet and laser marking is performed with the peripheral edge of the sheet fixed by a ring frame, the warpage of the wafer is corrected. Since it is maintained, printing accuracy is improved.
Further, since the sheet also serves as a dicing sheet, it is not necessary to prepare a separate dicing sheet, and productivity is significantly improved.
In Patent Document 2, a wafer is fixed on a protective film forming and dicing sheet, and the protective film forming layer is heated and cured in a state where the wafer is fixed, thereby forming a protective film on the wafer.

JP 2009-138026 A JP 2006-140348 A

However, in the protective film forming and dicing sheet having the above configuration, when the protective film forming film corresponding to the protective film forming layer is peeled off after heat curing, the surface of the protective film formed from the protective film forming film is printed in the laser printing process. There was room for improvement in the visibility of the part. There is also a need for further compatibility between wafer stickability and pick-up suitability after thermosetting.
Moreover, in the dicing sheet in which the protective film-forming film is laminated on the adhesive layer of the adhesive sheet, the protective film-forming film (protective film) and the adhesive layer are used when dicing the wafer to which the dicing sheet is attached. In the meantime, there is a problem that the cutting water enters and the manufactured chip with a protective film is contaminated.

  The present invention is highly effective in suppressing the phenomenon that cutting water enters between the protective film-forming film (protective film) and the adhesive layer when used when dicing a workpiece such as a wafer, and is suitable for pick-up during chip manufacturing. A protective film-forming composite sheet, a chip with a protective film, and a method for producing a chip with a protective film, which can manufacture a chip with a protective film that is excellent in visibility of the laser-printed portion on the surface of the protective film Objective.

  For the pressure-sensitive adhesive layer of the composite sheet for forming a protective film, the inventors include an energy ray-curable acrylic polymer containing a structural unit derived from methyl methacrylate at a predetermined content and having an energy ray polymerizable group introduced therein. The present invention has been completed by finding that the above-mentioned problems can be solved by forming from the pressure-sensitive adhesive composition.

That is, the present invention provides the following [1] to [13].
[1] A protective film-forming composite sheet comprising a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, and a protective film-forming film laminated directly on the pressure-sensitive adhesive layer,
The pressure-sensitive adhesive composition containing an energy ray-curable acrylic copolymer in which the pressure-sensitive adhesive layer introduces an energy ray-polymerizable group into an acrylic polymer (X) containing 10% by mass or more of a structural unit (x1) derived from methyl methacrylate. A composite sheet for forming a protective film, which is a layer formed from a product.
[2] For forming a protective film according to [1], wherein a cured region in which at least a part of the pressure-sensitive adhesive layer is cured is formed, and the protective film-forming film is directly laminated on the cured region. Composite sheet.
[3] The composite sheet for forming a protective film according to the above [1] or [2], wherein the energy beam polymerizable group is a (meth) acryloyl group.
[4] The energy ray-curable acrylic copolymer is added to an acrylic polymer (X) containing a structural unit (x1) derived from methyl methacrylate and a structural unit (x2) derived from a functional group-containing monomer. The composite sheet for forming a protective film according to any one of the above [1] to [3], which is an acrylic copolymer obtained by reacting a polymerizable compound (Y) containing
[5] The composite sheet for forming a protective film according to [4], wherein the value of α calculated from the following formula (2) of the energy ray-curable acrylic copolymer is 20 or less.
Formula (2): α = [P] × [Q] × [R] / 100
[In Formula (2), [P] shows the content rate of the structural unit (x2) derived from a functional group containing monomer with respect to 100 mass parts of all the structural units of acrylic polymer (X). [Q] represents the equivalent of the polymerizable compound (Y) to 100 equivalents of the functional group derived from the functional group-containing monomer of the acrylic polymer (X). [R] represents the number of energy ray polymerizable groups of the polymerizable compound (Y). ]
[6] The protective film-forming composite sheet according to any one of [1] to [5], wherein the protective film-forming film contains (A) a polymer component and (B) a curable component. .
[7] The composite sheet for forming a protective film according to [6], wherein the (B) curable component includes (B1) a thermosetting component.
[8] After affixing the protective film-forming film of the protective film-forming composite sheet to a workpiece, without peeling the protective film-forming film from the protective film-forming composite sheet, at 130 ° C. for 2 hours The protective film-forming composite sheet according to [7], wherein the protective film has a gloss value of 40 or more when the protective film-forming film is cured under conditions to form a protective film.
[9] The composite sheet for forming a protective film according to any one of [1] to [8], wherein the base material is a base material containing polypropylene.
[10] A chip with a protective film having a protective film formed by curing the protective film-forming film of the composite sheet for protective film formation according to any one of [1] to [9] on the back surface of the chip .
[11] The chip with protective film according to [10], wherein the gloss value of the protective film measured from the side opposite to the side where the chip is provided is 40 or more.
[12] A method for producing a chip with a protective film, comprising the following steps (1) to (4).
Step (1): Step of attaching the composite sheet for forming a protective film according to any one of claims 1 to 9 to the back surface of the workpiece Step (2): Step of dicing the workpiece Step (3): The protection Step of curing the protective film-forming film without peeling off the adhesive sheet of the composite sheet for film formation (4): Picking up the diced workpiece with protective film obtained through the steps (1) to (3) Step 13 for obtaining chip with protective film [13] Chip with protective film obtained by the manufacturing method according to [12], wherein the protective film is measured from the side opposite to the side where the chip is present A chip with a protective film having a gloss value of 40 or more.

  The composite sheet for forming a protective film of the present invention has a high effect of suppressing the phenomenon that cutting water enters between the protective film-forming film (protective film) and the adhesive layer when used when dicing a workpiece such as a wafer. It is possible to manufacture a chip with a protective film that is excellent in pick-up property at the time of chip manufacture and excellent in the visibility of the laser printing portion on the surface of the protective film.

It is sectional drawing of the composite sheet for protective film formation which shows the 1st-4th structure of the composite sheet for protective film formation of this invention. It is sectional drawing of the composite sheet for protective film formation which shows the 5th-7th structure of the composite sheet for protective film formation of this invention.

  In the following description of the present specification, the value of the weight average molecular weight (Mw) of the resin is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method, and specifically described in the examples. It is a value measured based on the method.

Moreover, the value of the glass transition temperature (Tg) of the resin is a value obtained by converting the glass transition temperature (Tg _K ) of the absolute temperature (unit: K) calculated by the following formula (1) into the Celsius temperature (unit: ° C.). It is.
[In the above formula _{(1), W 1, W} 2, W 3, W 4 ··· shows the mass fraction of the monomer components constituting the resin _{(mass%), Tg 1, Tg 2} , Tg 3, Tg ₄ ... Indicates the glass transition temperature in terms of absolute temperature (K) of the homopolymer of the monomer component constituting the resin. ]

Further, in the present application, for example, “(meth) acrylate” is used as a term indicating both “acrylate” and “methacrylate”, and the same applies to other similar terms.
In the present application, examples of the “energy beam” include ultraviolet rays or electron beams, and ultraviolet rays or electron beams are preferable.

[Composite sheet for protective film formation]
The protective film-forming composite sheet of the present invention (hereinafter also simply referred to as “composite sheet”) comprises a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, and a protective film-forming film laminated directly on the pressure-sensitive adhesive layer. I have it.
1 and 2 are cross-sectional views of a composite sheet showing an example of the configuration of the composite sheet of the present invention.
The composite sheet of the present invention may be in the form of a long tape or a single-leaf label.

As 1st-4th structure of the composite sheet of this invention, composite sheet 1a, 1b, 1c, 1d as shown to Fig.1 (a)-(d) is mentioned.
As the composite sheet of the present invention, as in the composite sheet 1a of FIG. 1 (a), a pressure-sensitive adhesive sheet 10 having a pressure-sensitive adhesive layer 12 on a substrate 11, and a protective layer directly laminated on a part of the pressure-sensitive adhesive layer 12 The thing of the structure which has the film 20 for film formation is mentioned. The size of the pressure-sensitive adhesive sheet 10 included in the composite sheet 1a may be any shape that can include the protective film-forming film 20.
In the composite sheet 1a, the portion of the pressure-sensitive adhesive layer 12 that is exposed without the protective film-forming film 20 being laminated holds adhesiveness, and thus a jig such as a ring frame can be fixed.

In addition, the composite sheet of the present invention may have a configuration in which the protective film forming film 20 is directly laminated on the entire surface of the pressure-sensitive adhesive layer 12 as in the composite sheet 1b of FIG.
In the composite sheet 1b, the protective film-forming film 20 and the pressure-sensitive adhesive sheet 10 have the same shape.

  The composite sheet of the present invention has a configuration like the composite sheet 1b in which the protective film-forming film 20 is adjusted to a shape that can substantially include the shape of the workpiece such as a semiconductor wafer or the like. Alternatively, it may be configured as a composite sheet 1a laminated on the pressure-sensitive adhesive sheet 10 having a size larger than that of the protective film-forming film 20.

Further, the composite sheet of the present invention forms a cured region 12a in which at least a part of the pressure-sensitive adhesive layer 12 is cured, as in the composite sheet 1c of FIG. 1C, and is used for forming a protective film on the cured region 12a. It is good also as what has the structure which the film 20 laminated | stacked directly.
The cured region 12a is a region in a plan view where the pressure-sensitive adhesive layer 12 is cured on at least the surface of the pressure-sensitive adhesive layer 12.
The cured region 12a is preferably formed at least at the position where the protective film forming film 20 is laminated, and is formed over the entire region in the adhesive layer 12 by curing the entire region of the adhesive layer 12. Also good.

The composite sheet having a configuration like the composite sheet 1c in FIG. 1 (c) has excellent pick-up suitability when used during chip manufacture, and the protective film formed from the protective film-forming film has a high gloss value. A chip with a protective film excellent in visibility of the laser-printed portion on the film surface can be produced.
The reason why the composite sheet obtained is excellent in pick-up suitability when the chip is manufactured is that the formed cured region 12a is less fluid than the portion of the pressure-sensitive adhesive layer 12 other than the cured region 12a. This is probably because of this.
In addition, the reason why the gloss value of the protective film formed using the composite sheet is improved is that the cured region 12a is kept low in fluidity during heating, so that the protective film formed directly on the cured region 12a is formed. This is considered to be because the smoothness of the surface of the cured region 12a can be maintained even in the process of forming the protective film by heat curing the protective film.

Although it is preferable that the hardening area | region 12a is the same shape as the protective film formation film 20, the shape larger than the shape of the protective film formation film 20 and including the protective film formation film 20 may be sufficient.
Moreover, although the adhesiveness of the hardening area | region 12a falls, it is preferable that the surface of the adhesive layer 12 other than the hardening area | region 12a has high adhesiveness.

Since the pressure-sensitive adhesive layer 12 is a layer formed from a pressure-sensitive adhesive composition containing an energy ray-curable acrylic copolymer, the cured region 12a irradiates at least a part of the pressure-sensitive adhesive layer 12 with energy rays to It can be formed by curing part or all of the agent layer.
The degree of progress of the curing reaction of the pressure-sensitive adhesive layer in the cured region 12a is preferably 50% or more, more preferably 70% or more, still more preferably 90% or more, and still more preferably completely cured.
Irradiation of energy rays may be performed from the substrate 11 side, may be performed from the protective film forming film 20 side, or energy beam irradiation is performed before the protective film forming film 20 and the adhesive sheet are bonded together. May be performed from the side of the surface to be bonded to the protective film-forming film 20.
In addition, as in the composite sheet 1d of FIG. 1D, by providing the energy ray shielding layer 13 by printing or the like at a part of the boundary between the base material 11 and the pressure-sensitive adhesive layer 12, energy rays are emitted from the base material 11 side. By irradiating, the cured region 12a and the uncured and highly adhesive pressure-sensitive adhesive layer 12 can be easily formed separately.

Furthermore, when the composite sheet of the present invention is bonded to a jig such as a ring frame, the outer periphery of the composite sheet is improved as shown in FIGS. It is good also as a structure which provided the jig | tool adhesion layer 31 in the part.
The composite sheet 2a of FIG. 2A has a configuration in which a protective film-forming film 20 is laminated on a part of the pressure-sensitive adhesive layer 12, and a jig adhesive layer 31 is further provided. This composite sheet 2a has a pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer 12 is cured to form a cured region and the adhesive strength is reduced, or in order to facilitate peeling of the pressure-sensitive adhesive sheet 10 after the protective film is formed. Even in a case where the adhesive strength is reduced, the adhesive strength with the jig can be improved by providing the jig adhesive layer 31 on the pressure-sensitive adhesive layer 12.
2B, the protective film-forming film 20 and the pressure-sensitive adhesive sheet 10 have the same shape, and a jig adhesive layer 31 is provided on the outer periphery of the surface of the protective film-forming film 20. It has a configuration. The protective film forming film 20 does not have an adhesive force enough to bond the jig, and the adhesive force with the jig can be improved by providing the jig adhesive layer 31.
In addition, also in the composite sheet 2a of FIG. 2 (a) and the composite sheet 2b of (b), the adhesive layer 12 of the position which the protective film formation film 20 laminate | stacks is hardened for the above-mentioned reason, and a hardening area | region is. It is preferable to have a formed configuration.

The jig adhesion layer 31 can be formed of a double-sided pressure-sensitive adhesive sheet having a base material (core material) or a layer composed of a single layer of pressure-sensitive adhesive.
As a base material (core material) used for forming the jig | tool adhesion layer 31, the same thing as the base material 11 mentioned later can be used, for example, a polyester film, a polypropylene film, a polycarbonate film, a polyimide film, a fluororesin A film, a liquid crystal polymer film, etc. are mentioned, A polypropylene film is preferable.
The pressure-sensitive adhesive used to form the jig adhesive layer 31 includes energy ray-curable pressure-sensitive adhesives, pressure-sensitive adhesives, and heat-expandable pressure-sensitive adhesives according to the classification of the pressure-sensitive adhesive functions. According to the classification based on the main resin in the adhesive, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, vinyl ether adhesives and the like can be mentioned.
The thickness of the jig | tool adhesion layer 31 becomes like this. Preferably it is 1-80 micrometers, More preferably, it is 5-60 micrometers, More preferably, it is 10-40 micrometers.

Moreover, as shown in FIG.2 (c), the composite sheet 2c which has the adhesive layer in which the several layer was laminated | stacked as a composite sheet of this invention may be sufficient.
That is, the composite sheet 2c in FIG. 2C has a cured region 12a, and in addition to the adhesive layer 12 directly laminated with the protective film forming film 20, between the base material 11 and the adhesive layer 12, In addition to the pressure-sensitive adhesive layer 12, a jig bonding pressure-sensitive adhesive layer 41 is provided.
By providing the jig bonding adhesive layer 41, when bonding the area where the pressure sensitive adhesive layer 12 does not exist and the jig such as the ring frame among the areas of the jig bonding adhesive layer 41 in plan view. In addition, the adhesiveness at the interface between the protective film-forming film 20 and the pressure-sensitive adhesive layer 12 can be controlled while improving the adhesiveness to the jig. As a result, when manufacturing a chip using this composite sheet, the workability of picking up a chip with a protective film can be improved.
In addition, also in the composite sheet 2c of FIG.2 (c), it is preferable for the above-mentioned reason that it has the structure by which the adhesive layer 12 of the position which the film 20 for protective film formation laminates was hardened, and the hardening area | region was formed. .

Examples of the pressure-sensitive adhesive forming the jig bonding pressure-sensitive adhesive layer 41 include the same pressure-sensitive adhesive as that forming the jig bonding layer 31 described above, but a pressure-sensitive adhesive that expresses higher adhesiveness than the pressure-sensitive adhesive layer 12. Is preferred.
The thickness of the pressure-sensitive adhesive layer 41 for jig bonding is preferably 1 to 50 μm, more preferably 3 to 40 μm, and still more preferably 3 to 30 μm.

  In the composite sheet of the present invention, the surface of the protective film forming film 20, the surface of the pressure-sensitive adhesive layer 12 that is exposed without being laminated, the surface of the jig adhesive layer 31, and A release sheet may be further provided on the surface of the pressure-sensitive adhesive layer 41 for jig adhesion that is exposed without the pressure-sensitive adhesive layer 12 being laminated.

Examples of the release sheet include those obtained by applying a release agent to at least one surface of the release sheet substrate and performing a release treatment.
As a base material for peeling sheets, the same thing as the resin film which comprises the below-mentioned base material is mentioned.
Examples of the release agent include alkyd release agents, silicone release agents, fluorine release agents, unsaturated polyester release agents, polyolefin release agents, and wax release agents. Among these, alkyd release agents, silicone release agents, and fluorine release agents are preferable from the viewpoint of heat resistance.
Although there is no restriction | limiting in particular in the thickness of a peeling sheet, Preferably it is 10-500 micrometers, More preferably, it is 15-300 micrometers, More preferably, it is 20-200 micrometers.

  Hereinafter, the details of the base material, the pressure-sensitive adhesive layer, and the protective film-forming film constituting the composite sheet of the present invention will be described.

<Base material>
Examples of the base material for the pressure-sensitive adhesive sheet used in the present invention include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, and polyethylene naphthalate. Film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid ester copolymer film, polystyrene film, Examples of the resin film include polycarbonate films, polyimide films, and fluororesin films.
These resin films may be crosslinked films.
Moreover, as a base material, the single layer film which consists of 1 type of resin films may be sufficient, and the multilayer film which laminated | stacked 2 or more types of resin films may be sufficient. In addition, a colored resin film may be used as the substrate.

Among these, a resin film excellent in heat resistance is preferable.
Even when the protective film-forming film is thermosetting and the protective film-forming film is heat-cured before being peeled off from the pressure-sensitive adhesive sheet, by using a resin film having excellent heat resistance as a base material, It is possible to suppress damage due to heat of the semiconductor device and to prevent occurrence of defects in the semiconductor device manufacturing process.
Furthermore, as a base material, it has excellent heat resistance and has appropriate flexibility so that it has expandability, and when a composite sheet is used for manufacturing a chip, good pickability is easily maintained. Therefore, a base material including a polypropylene film is preferable.
In addition, as a structure of the base material containing a polypropylene film, the single layer structure which consists only of a polypropylene film may be sufficient, and the multilayer structure which consists of a polypropylene film and another resin film may be sufficient.

  The thickness of the substrate is preferably 10 to 500 μm, more preferably 15 to 300 μm, and still more preferably 20 to 200 μm.

<Adhesive layer>
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive composition containing an energy ray-curable acrylic copolymer in which an energy ray polymerizable group is introduced into an acrylic polymer (X) containing 10% by mass or more of a structural unit derived from methyl methacrylate (x1). It is a layer formed from.
The pressure-sensitive adhesive composition preferably contains and is formed of a photopolymerization initiator from the viewpoint of allowing the curing reaction to proceed efficiently in a short time in addition to the energy ray-curable acrylic copolymer. From the viewpoint of improving the cohesive strength and adhesive strength of the pressure-sensitive adhesive layer, it is preferable to contain a crosslinking agent.

  In addition, like the structure of the composite sheets 1c and 1d shown in FIGS. 1C and 1D, at least a part of the pressure-sensitive adhesive layer 12 of the pressure-sensitive adhesive sheet 10 used in the present invention includes a cured region 12a. preferable.

The thickness of an adhesive layer becomes like this. Preferably it is 1-100 micrometers, More preferably, it is 3-50 micrometers, More preferably, it is 5-25 micrometers.
Hereinafter, each component contained in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer will be described in detail.

[Energy ray curable acrylic copolymer]
The energy ray curable acrylic copolymer used in the present invention is an acrylic copolymer in which an energy ray polymerizable group is introduced into an acrylic polymer (X) containing 10% by mass or more of a structural unit (x1) derived from methyl methacrylate. .
By containing an energy ray-curable acrylic copolymer in the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer, when producing a chip by sticking a composite sheet to a workpiece such as a wafer, the pressure-sensitive adhesive is irradiated with energy rays. Since the adhesive strength of the layer can be reduced, the pickup property can be improved. In addition, a cured region can be formed in the pressure-sensitive adhesive layer.

The energy ray polymerizable group introduced into the acrylic polymer (X) is a group containing an energy ray polymerizable carbon-carbon double bond, and examples thereof include a (meth) acryloyl group and a vinyl group. Among these, a (meth) acryloyl group is preferable from the viewpoint of easy introduction of the energy beam polymerizable group.
The energy beam polymerizable group may be introduced into the main chain of the acrylic polymer (X) or may be introduced into the side chain.
The energy beam polymerizable group may be bonded to the acrylic polymer (X) via an alkylene group, an alkyleneoxy group, a polyalkyleneoxy group, or the like.

The weight average molecular weight (Mw) of the energy ray curable acrylic copolymer is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,200,000, still more preferably 300,000 to 1,000,000, still more preferably 400,000 to 800,000.
If Mw is 100,000 or more, a protective film having a high gloss value can be formed. In addition, the phenomenon that the pressure-sensitive adhesive layer is transferred to the surface of the protective film-forming film and contaminates the surface of the protective film-forming film can be suppressed.
On the other hand, if Mw is 1,500,000 or less, the adhesiveness between the pressure-sensitive adhesive layer and the protective film-forming film is good, and the cutting water enters between the pressure-sensitive adhesive layer and the protective film-forming film during dicing. Can be suppressed.

  The blending amount of the energy ray curable acrylic copolymer with respect to all active ingredients (100% by mass) of the pressure-sensitive adhesive composition is preferably 60 to 100% by mass, more preferably 70 to 99.9% by mass, and still more preferably. It is 80-99 mass%, More preferably, it is 90-98 mass%.

The energy ray curable acrylic copolymer is preferably an acrylic copolymer obtained by reacting an acrylic polymer (X) and a polymerizable compound (Y) having an energy ray polymerizable group. The acrylic polymer It is more preferable that (X) includes a structural unit (x1) derived from methyl methacrylate and a structural unit (x2) derived from a functional group-containing monomer.
Energy ray polymerization of the polymerizable compound (Y) in the main chain and / or side chain of the acrylic polymer (X) by the reaction between the acrylic polymer (X) and the substituent in the polymerizable compound (Y). By introducing a functional group, an energy ray curable acrylic copolymer is obtained.
Hereinafter, the acrylic polymer (X) and the polymerizable compound (Y) will be described.

(Acrylic polymer (X))
The acrylic polymer (X) contains 10% by mass or more of the structural unit (x1) derived from methyl methacrylate.
By using the acrylic polymer (X) containing 10 mass% or more of the structural unit derived from methyl methacrylate (x1), the fluidity at the time of heating is kept low with respect to the pressure-sensitive adhesive layer to be formed. When heat-curing, the smoothness of the surface of an adhesive layer can be maintained and the gloss value of a protective film can be improved. Moreover, the adhesiveness of the adhesive layer formed and the film for protective film formation can be maintained favorable. As a result, when the resulting composite sheet is used for chip manufacture, the pickup is performed while suppressing the phenomenon that cutting water enters between the protective film-forming film (protective film) and the adhesive layer during dicing. The property can be maintained well.

  From the above viewpoint, the content of the structural unit (x1) is preferably 10 to 80% by weight, more preferably 15 to 75% by weight, based on the total structural unit (100% by weight) of the acrylic polymer (X). More preferably, it is 20-70 mass%, More preferably, it is 25-65 mass%, More preferably, it is 30-60 mass%.

The acrylic polymer (X) preferably contains a structural unit (x2) derived from a functional group-containing monomer together with the structural unit (x1).
The functional group of the structural unit (x2) reacts with the substituent of the polymerizable compound (Y).
Examples of the functional group include a hydroxy group, a carboxy group, an epoxy group, an amino group, a cyano group, a keto group, a nitrogen atom-containing cyclic group, and an alkoxysilyl group.

Examples of the functional group-containing monomer constituting the structural unit (x2) include a hydroxy group-containing monomer, a carboxy group-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer, and a nitrogen atom. Examples thereof include a monomer having a containing ring and an alkoxysilyl group-containing monomer.
These functional group-containing monomers may be used alone or in combination of two or more.
Of these, hydroxy group-containing monomers are preferred.

Examples of the hydroxy-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl (meth) ) Hydroxyalkyl (meth) acrylates such as acrylate and 4-hydroxybutyl (meth) acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.
Among these, 2-hydroxyethyl (meth) acrylate is preferable.

  Examples of the carboxy group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid.

Examples of the epoxy-containing monomer include an epoxy group-containing (meth) acrylic acid ester and a non-acrylic epoxy group-containing monomer.
Examples of the epoxy group-containing (meth) acrylic acid ester include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, (3,4-epoxycyclohexyl) methyl (meth) acrylate, and 3-epoxycyclo-2- Hydroxypropyl (meth) acrylate etc. are mentioned.
Examples of the non-acrylic epoxy group-containing monomer include glycidyl crotonate and allyl glycidyl ether.
These functional group-containing monomers may be used alone or in combination of two or more.

The content ratio of the structural unit (x2) is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, still more preferably 7 to 27% by mass, with respect to all the structural units of the acrylic polymer (X). More preferably, it is 10-25 mass%.
If the content rate of a structural unit (x2) is 1 mass% or more, the reactive point with polymeric compound (Y) will increase, and the additional amount of polymeric compound (Y) can be increased. As a result, a pressure-sensitive adhesive layer with higher curability can be formed.
On the other hand, if the content ratio of the structural unit (x2) is 35% by mass or less, a sufficient pot life is ensured in the step of applying the adhesive composition solution as a coating liquid and forming the adhesive layer. Can do. Moreover, the degree of hydrophilicity of the pressure-sensitive adhesive layer to be formed is prevented from becoming excessively large, and the phenomenon that cutting water enters between the pressure-sensitive adhesive layer and the protective film-forming film (protective film) is prevented. Can do.

The acrylic polymer (X) is a structural unit derived from an alkyl (meth) acrylate (x3) from the viewpoint of improving the adhesiveness of the adhesive layer and improving the adhesion between the adhesive layer and the protective film-forming film. It is preferable to contain.
The alkyl (meth) acrylate constituting the structural unit (x3) is not particularly limited as long as it is a monomer that can be copolymerized with the functional group-containing monomer and methyl methacrylate. From the viewpoint of improving the adhesion between the agent layer and the protective film-forming film, an alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms or a (meth) acrylate having a cyclic skeleton is preferable, and the number of carbon atoms is 2 to 2. More preferred are alkyl (meth) acrylates having 18 alkyl groups.
In addition, as carbon number of the alkyl group which alkyl (meth) acrylate has, Preferably it is 2-18, More preferably, it is 2-12, More preferably, it is 4-10.

Examples of the alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth). Examples include acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, and the like.
Examples of the (meth) acrylate having a cyclic skeleton include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, and imide acrylate. Etc.
These monomers may be used alone or in combination of two or more.
Among these, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable from the viewpoint of improving the adhesiveness of the adhesive layer and improving the adhesion between the adhesive layer and the protective film-forming film. -Ethylhexyl (meth) acrylate is more preferred.

  The content ratio of the structural unit (x3) is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, and still more preferably 20 to 65% by mass with respect to all the structural units of the acrylic polymer (X). More preferably, it is 25-60 mass%.

The acrylic polymer (X) may contain other structural units other than the structural units (x1) to (x3).
Examples of monomers from which other structural units are derived include monomers such as methyl acrylate, acrylonitrile, and styrene.

  The form of copolymerization of the acrylic polymer (X) is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

  The weight average molecular weight (Mw) of the acrylic polymer (X) is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,200,000, still more preferably 300,000 to 1,000,000.

  Moreover, the glass transition temperature (Tg) of acrylic polymer (X) adjusts the adhesiveness of an adhesive layer to an appropriate range, and improves the adhesiveness of the adhesive layer formed and the film for protective film formation. However, from the viewpoint of maintaining good pickup suitability, it is preferably −50 to 10 ° C., more preferably −40 to 10 ° C., and further preferably −30 to 10 ° C.

A method for synthesizing the acrylic polymer (X) is not particularly limited. For example, a solution polymerization method in the presence of a solvent, a polymerization initiator, a chain transfer agent, an emulsifier, a polymerization initiator, or a chain transfer agent is used. , And a method of emulsion polymerization in an aqueous system in the presence of a dispersant or the like. In the polymerization method, additives such as a thickener, a wetting agent, a leveling agent, and an antifoaming agent may be added as necessary.
The polymerization reaction is preferably performed at a temperature of 60 to 100 ° C. for 2 to 8 hours.
The density | concentration of the raw material monomer at the time of superposition | polymerization is 30-70 mass% normally, Preferably it is 40-60 mass%.

Examples of the polymerization initiator used in the polymerization include persulfates such as potassium persulfate and ammonium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4- Azo compounds such as dimethylvaleronitrile), peroxides such as hydrogen peroxide, benzoyl peroxide, lauryl peroxide, redox polymerization initiators composed of a combination of ammonium persulfate and sodium sulfite, acidic sodium sulfite, etc. Can be mentioned.
The addition amount of the polymerization initiator is preferably 0.2 to 2 parts by mass, more preferably 0.3 to 1 part by mass with respect to 100 parts by mass of the total amount of raw material monomers.

Examples of the chain transfer agent used in the polymerization include alkyl mercaptans such as octyl mercaptan, nonyl mercaptan, decyl mercaptan, dodecyl mercaptan, octyl thioglycolate, nonyl thioglycolate, 2-ethylhexyl thioglycolate, Examples include thioglycolic acid esters such as β-mercaptopropionic acid-2-ethylhexyl, 2,4-diphenyl-4-methyl-1-pentene, 1-methyl-4-isopropylidene-1-cyclohexene, and the like.
Among these, thioglycolic acid esters, 2,4-diphenyl-4-methyl-1-pentene, and 1-methyl-4-isopropylidene-1-cyclohexene are preferable.
The addition amount of the chain transfer agent is preferably 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers.

(Polymerizable compound (Y))
The polymerizable compound (Y) is a compound having a polymerizable group containing an energy beam polymerizable carbon-carbon double bond, which reacts with the acrylic polymer (X) to form a main chain of the acrylic polymer (X) and It is a compound that can introduce the polymerizable group into the side chain.
The polymerizable compound (Y) has a substituent capable of reacting with the functional group of the acrylic polymer (X) and 1 to 1 polymerizable group containing an energy ray polymerizable carbon-carbon double bond per molecule. A compound having 5 is preferable.
As a substituent which reacts with the functional group which acrylic polymer (X) has, an isocyanate group, a carboxyl group, an epoxy group etc. are mentioned, for example, An isocyanate group is preferable.
Moreover, (meth) acryloyl group, a vinyl group, etc. are mentioned as a polymeric group containing an energy-beam polymerizable carbon-carbon double bond, A (meth) acryloyl group is preferable.

Specific examples of the polymerizable compound (Y) include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, Examples include (meth) acrylic acid.
These polymerizable compounds (Y) may be used alone or in combination of two or more.
Among these, it has a preferred isocyanate group as a substituent that reacts with the functional group of the acrylic polymer (X), and the distance between the acrylic polymer (X) and the polymerizable group is a suitable compound. From the viewpoint, (meth) acryloyloxyethyl isocyanate is preferred.

  As a method for synthesizing the energy ray curable acrylic copolymer, for example, when introducing a polymerizable compound (Y) having an isocyanate group into an acrylic polymer (X) having a hydroxy group, in an organic solution such as ethyl acetate. And a method of using a catalyst such as dibutyltin laurate at room temperature and normal pressure for about 24 hours.

  The blending amount of the polymerizable compound (Y) with respect to 100 equivalents of the functional group of the acrylic polymer (X) is preferably 20 to 100 from the viewpoint of improving the laser marking suitability of the protective film formed using the composite sheet. The equivalent amount, more preferably 30 to 95 equivalents, still more preferably 40 to 90 equivalents, and still more preferably 55 to 85 equivalents.

  Moreover, the compounding quantity of the polymeric compound (Y) with respect to 100 mass parts of acrylic polymers (X) is the laser marking aptitude of the protective film formed using a composite sheet, and the adhesive layer and the protective film-forming film ( From the viewpoint of improving the adhesion to the protective film, the amount is preferably 1 to 40 parts by mass, more preferably 5 to 35 parts by mass, still more preferably 10 to 30 parts by mass, and still more preferably 14 to 25 parts by mass. .

In addition, about the relationship of the compounding quantity of acrylic polymer (X) and polymeric compound (Y), it is preferable that the value of (alpha) calculated from following formula (2) is 20 or less.
Formula (2): α = [P] × [Q] × [R] / 100
In said formula (2), [P] shows the content rate of the structural unit (x2) derived from a functional group containing monomer with respect to 100 mass parts of all the structural units of acrylic polymer (X). [Q] represents the equivalent of the polymerizable compound (Y) to 100 equivalents of the functional group derived from the functional group-containing monomer of the acrylic polymer (X). [R] represents the number of energy ray polymerizable groups of the polymerizable compound (Y).

The value of α calculated from the formula (2) is an index of adhesion between the pressure-sensitive adhesive layer to be formed and the protective film-forming film (protective film). The smaller the value, the higher the adhesion, The effect of suppressing the phenomenon that cutting water enters between the protective film-forming film (protective film) and the adhesive layer during dicing of the workpiece is high.
The value of α is preferably 20 or less, more preferably 18 or less, still more preferably 17 or less, and more preferably 16 or less. Moreover, from a viewpoint of making pick-up suitability favorable, Preferably it is 1 or more, More preferably, it is 5 or more.

On the other hand, in general, when the adhesiveness between the pressure-sensitive adhesive layer and the protective film-forming film (protective film) increases, the pickup suitability often decreases.
However, in the present invention, by using an energy ray curable acrylic copolymer containing a predetermined amount of the structural unit (x1) derived from methyl methacrylate, even if the value of α is low, it has excellent pickup suitability.
In addition, in the present invention, by using an energy ray curable acrylic copolymer containing a predetermined amount of the structural unit (x1) derived from methyl methacrylate, the fluidity during heating of the pressure-sensitive adhesive layer to be formed is kept low. When the protective film-forming film is cured by heating, the smoothness of the surface of the pressure-sensitive adhesive layer can be maintained, and the gloss value of the protective film can be improved.

[Photopolymerization initiator]
By compounding a photopolymerization initiator, when the pressure-sensitive adhesive layer is irradiated with energy rays to cure the pressure-sensitive adhesive layer, the curing of the pressure-sensitive adhesive layer is shortened even if the polymerization curing time is shortened and the amount of light irradiation is small. Can proceed to form a hardened region.

Examples of the photopolymerization initiator include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds and peroxide compounds, and photosensitizers such as amines and quinones. .
Specific photopolymerization initiators include, for example, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, Examples include dibenzyl, diacetyl, β-chloranthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
These photopolymerization initiators may be used alone or in combination of two or more.

  The blending amount of the photopolymerization initiator is preferably 0.1 to 100 parts by mass of the acrylic copolymer from the viewpoint of sufficiently proceeding the curing reaction, improving the pickup suitability, and suppressing the generation of the residue. 10 mass parts, More preferably, it is 1-7 mass parts, More preferably, it is 2-5 mass parts.

[Crosslinking agent]
The pressure-sensitive adhesive composition used in the present invention preferably further contains a crosslinking agent.
By containing the cross-linking agent, the cross-linking reaction with the functional group of the acrylic polymer (X) forms a network structure, thereby improving the cohesive force of the formed pressure-sensitive adhesive layer and controlling the adhesive force. be able to.
Examples of the crosslinking agent include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, organic polyvalent imine compounds, and the like.

  Examples of the organic polyvalent isocyanate compound include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and organic polyvalent isocyanate compounds. Examples thereof include terminal isocyanate urethane prepolymers obtained by reacting an isocyanate compound with a polyol compound.

  Specific examples of organic polyvalent isocyanate compounds include tolylene diisocyanate compounds such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylene diisocyanate. Xylene diisocyanate compounds such as diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane Examples include -2,4'-diisocyanate, lysine isocyanate, and polyhydric alcohol adducts thereof.

  Examples of the organic polyvalent epoxy compound include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, and ethylene glycol diester. Examples thereof include glycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine and the like.

  Examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane- Examples include tri-β-aziridinyl propionate and N, N′-toluene-2,4-bis (1-aziridinecarboxamide) triethylenemelamine.

  The blending amount of the crosslinking agent is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and further preferably 0.3 to 5 parts by mass with respect to 100 parts by mass of the acrylic copolymer. is there.

[Other additives]
The pressure-sensitive adhesive composition used in the present invention may contain other additives such as a tackifier resin, an antioxidant, a stabilizer, a softener, a filler, a pigment, and a dye.
Examples of tackifying resins include rosin resins, hydrogenated rosin resins, terpene resins, hydrogenated terpene resins, C5 petroleum resins obtained by copolymerizing C5 fractions, and hydrogenation of C5 petroleum resins. Examples thereof include petroleum resins, C9 petroleum resins obtained by copolymerizing C9 fractions, hydrogenated petroleum resins of C9 petroleum resins, and the like.

<Method for producing adhesive sheet>
There is no restriction | limiting in particular as a manufacturing method of an adhesive sheet. For example, an organic solvent is added to each component described above to prepare a solution of the pressure-sensitive adhesive composition. And it can manufacture by apply | coating the solution of this adhesive composition by a well-known method on a base material, forming a coating film, drying the said coating film, and forming an adhesive layer.
In addition, the said adhesive solution is apply | coated on the above-mentioned peeling sheet, an adhesive layer is formed on a peeling sheet, a base material is laminated | stacked on the said adhesive layer, and it is good also as an adhesive sheet with a peeling sheet. . In addition, at the time of use of an adhesive sheet, the said peeling sheet is removed and the film for protective film formation is laminated | stacked on the exposed adhesive layer.

  Examples of the organic solvent include toluene, ethyl acetate, methyl ethyl ketone, and the like. Moreover, as solid content concentration of the solution of an adhesive composition, Preferably it is 10-80 mass%, More preferably, it is 25-70 mass%, More preferably, it is 45-65 mass%.

  Examples of the method for applying the solution of the pressure-sensitive adhesive composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

In addition, when forming a hardening area | region in the formed adhesive layer, there is no restriction | limiting in particular as a formation method of the said hardening area | region. For example, in the above-described method for producing a pressure-sensitive adhesive sheet, it is sufficient to irradiate energy rays such as ultraviolet rays from the release sheet side or the substrate side to cure the pressure-sensitive adhesive layer.
As the irradiation energy ray, ultraviolet rays are preferable.
Illuminance of the irradiated ultraviolet ray is preferably 100~250mW / cm ^2, light quantity of the ultraviolet rays is preferably 350~700mJ / cm ^2.

<Protective film-forming film>
Although there is no restriction | limiting in particular as a film for protective film formation, It is preferable that (A) polymer component and (B) sclerosing | hardenable component are included, and also (C) coloring agent, (D) coupling agent, (E ) An inorganic filler and (F) a general-purpose additive.
Hereinafter, the components (A) to (G) contained in the protective film-forming film will be described.

[(A) Polymer component]
The “polymer component” means a compound having a weight average molecular weight of 20,000 or more and having at least one repeating unit. By containing the polymerizable component (A) in the protective film-forming film, it is possible to mainly impart flexibility and film-forming property to the protective film-forming film and to improve the sheet property maintaining property. .
(A) As a weight average molecular weight (Mw) of a polymer component, Preferably it is 20,000 or more, More preferably, it is 20,000-3 million, More preferably, it is 50,000-2 million, More preferably, it is 100,000-1.5 million. .

  The content of the component (A) is preferably 5 to 50% by mass, more preferably 8 to 40% by mass, and further preferably 10 to 30% by mass with respect to the total amount (100% by mass) of the protective film-forming film. More preferably, it is 12 to 25% by mass.

(A) As the polymer component, (A1) an acrylic polymer is preferable. Other than the component (A1), (A2) such as polyester, phenoxy resin, polycarbonate, polyether, polyurethane, polysiloxane, rubber polymer, etc. A non-acrylic polymer may be used.
These polymer components may be used alone or in combination of two or more.

((A1) acrylic polymer)
(A1) The weight average molecular weight (Mw) of the acrylic polymer is preferably 20,000 to 3,000,000, more preferably 100,000 to 150, from the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film. 10,000, more preferably 150,000 to 1,200,000, still more preferably 250,000 to 1,000,000.

  (A1) The glass transition temperature (Tg) of the acrylic polymer is that the protective film formed from the protective film-forming film has a protective film manufactured using a composite sheet and a viewpoint of adhesion to the adherend. From the viewpoint of improving the reliability of the chip, it is preferably −60 to 50 ° C., more preferably −50 to 40 ° C., still more preferably −40 to 30 ° C., and still more preferably −35 to 20 ° C.

(A1) As an acrylic polymer, the polymer which has alkyl (meth) acrylate as a main component is mentioned, Specifically, the structural unit derived from the alkyl (meth) acrylate which has a C1-C18 alkyl group. An acrylic polymer containing (a1) is preferable, and an acrylic copolymer containing the structural unit (a2) derived from the functional group-containing monomer together with the structural unit (a1) is more preferable.
(A1) A component may be used individually or in combination of 2 or more types.
When the component (A1) is a copolymer, the form of the copolymer may be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer.

(Structural unit (a1))
The number of carbon atoms of the alkyl group of the alkyl (meth) acrylate constituting the structural unit (a1) is preferably 1 to 18, more preferably from the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film. Is 1-12, more preferably 1-8.

Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl ( Examples include meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.
In addition, you may use these alkyl (meth) acrylates individually or in combination of 2 or more types.

Among these, alkyl (meth) acrylates having an alkyl group having 4 or more carbon atoms are preferred from the viewpoint of increasing the gloss value of the protective film formed from the protective film-forming film and improving the laser marking suitability of the protective film. Alkyl (meth) acrylate having an alkyl group having 4 to 6 carbon atoms is more preferable, and butyl (meth) acrylate is more preferable.
From the above viewpoint, the content ratio of the structural unit derived from the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms is preferably 1 to 70% by mass with respect to all structural units of the (A1) acrylic polymer, More preferably, it is 5-65 mass%, More preferably, it is 10-60 mass%.

Moreover, from a viewpoint of the reliability improvement of the chip | tip with a protective film manufactured using the composite sheet of this invention, the alkyl (meth) acrylate which has a C1-C3 alkyl group is preferable, and methyl (meth) acrylate is more. preferable.
From the above viewpoint, the content ratio of the structural unit derived from the alkyl (meth) acrylate having an alkyl group having 1 to 3 carbon atoms is preferably 1 to 60% by mass with respect to all structural units of the (A1) acrylic polymer. More preferably, it is 3-50 mass%, More preferably, it is 5-40 mass%.

  The content ratio of the structural unit (a1) is preferably 50% by mass or more, more preferably 50 to 99% by mass, still more preferably 55 to 90% by mass, based on the total structural unit of the (A1) acrylic polymer. More preferably, it is 60-80 mass%.

(Structural unit (a2))
Examples of the functional group-containing monomer constituting the structural unit (a2) include a hydroxy group-containing monomer, a carboxy group-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer, and a nitrogen atom. Examples thereof include a monomer having a containing ring and an alkoxysilyl group-containing monomer.
These functional group-containing monomers may be used alone or in combination of two or more.
Of these, hydroxy group-containing monomers are preferred.

  Although what was illustrated as a functional group containing monomer which comprises a structural unit (x2) as a hydroxy containing monomer is mentioned, 2-hydroxyethyl (meth) acrylate is preferable.

Examples of the carboxy group-containing monomer include those exemplified as the functional group-containing monomer constituting the structural unit (x2).
By using a carboxy group-containing monomer, when a carboxyl group is introduced into the (A1) acrylic polymer and the protective film-forming film contains an energy ray curable component as the (B) curable component, ( The compatibility between the component (B) and the component (A) is improved.

In addition, when using an epoxy-type thermosetting component as (B) sclerosing | hardenable component mentioned later, since the epoxy group in an epoxy-type thermosetting component will react, it originates in a carboxyl group-containing monomer. The content of structural units is preferably small.
(B) When using an epoxy thermosetting component as the curable component, the content of the structural unit derived from the carboxy group-containing monomer is preferably 0 to the total structural unit of the (A1) acrylic polymer. It is 10 mass%, More preferably, it is 0-5 mass%, More preferably, it is 0-2 mass%, More preferably, it is 0 mass%.

  Examples of the epoxy-containing monomer include those exemplified as the functional group-containing monomer constituting the structural unit (x2). Epoxy group-containing (meth) acrylic acid esters are preferable, and glycidyl (meth) acrylate is more preferable.

(A1) When the structural unit constituting the acrylic polymer contains a structural unit derived from an epoxy group-containing monomer, the gloss value of the protective film formed from the protective film-forming film can be increased. The laser marking aptitude can be improved.
The content ratio of the structural unit derived from the epoxy group-containing monomer is good in terms of increasing the gloss value of the protective film formed from the protective film-forming film and the reliability of the chip obtained by using the composite sheet of the present invention. (A1) Preferably it is 1-30 mass% with respect to all the structural units of an acryl-type polymer, More preferably, it is 5-27 mass%, More preferably, it is 10-24 mass%.

  The content of the structural unit (a2) is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, and still more preferably 10 to 40% by mass with respect to the total structural unit of the (A1) acrylic polymer. More preferably, it is 20-40 mass%.

(Constitutional units derived from other monomers)
In addition, (A1) acrylic polymer may have structural units derived from other monomers other than the structural units (a1) and (a2) as long as the effects of the present invention are not impaired.
Examples of other monomers include vinyl acetate, styrene, ethylene, α-olefin and the like.

((A2) non-acrylic resin)
If necessary, the protective film-forming film may contain (A2) a non-acrylic resin as a resin component other than the above-described (A1) acrylic polymer.
Examples of (A2) non-acrylic resins include polyesters, phenoxy resins, polycarbonates, polyethers, polyurethanes, polysiloxanes, rubber polymers, and the like.
These resins may be used alone or in combination of two or more.

  (A2) The weight average molecular weight of the non-acrylic resin is preferably 20,000 or more, more preferably 20,000 to 100,000, and still more preferably 20,000 to 80,000.

(A2) The non-acrylic resin may be used alone, but by using it together with the above-mentioned (A1) acrylic polymer, the delamination between the pressure-sensitive adhesive sheet and the protective film-forming film can be easily performed. And generation of voids and the like can be suppressed.
When (A2) non-acrylic resin is used in combination with the above-mentioned (A1) acrylic polymer, the mass ratio of (A2) non-acrylic resin to (A1) acrylic polymer (A1) [(A2) / (A1)] is preferably 1/99 to 60/40, more preferably 1/99 to 30/70, from the above viewpoint.

  In addition, the (A1) acrylic polymer and the phenoxy resin having an epoxy group in the case where the structural unit constituting the (A1) acrylic polymer includes a structural unit derived from an epoxy group-containing monomer has thermosetting properties. However, these are not (B) curable components, but are included in the concept of (A) polymer components.

[(B) Curing component]
(B) The curable component plays a role of curing the protective film-forming film to form a hard protective film, and is a compound having a weight average molecular weight of less than 20,000.
(B) It is preferable to use a thermosetting component (B1) and / or an energy ray curable component (B2) as the curable component, and from the viewpoint of suppressing coloring of the protective film formed from the protective film-forming film, curing It is more preferable to use at least the thermosetting component (B1) from the viewpoint of sufficiently proceeding the reaction and from the viewpoint of cost reduction.
The thermosetting component (B1) preferably contains at least a compound having a functional group that reacts by heating.
The energy ray-curable component (B2) contains a compound (B21) having a functional group that reacts by irradiation with energy rays, and is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams.
Curing is realized by the functional groups of these curable components reacting to form a three-dimensional network structure.
(B) The weight average molecular weight (Mw) of the curable component is used in combination with the component (A), thereby suppressing the viscosity of the composition forming the protective film-forming film and improving the handleability. Therefore, it is preferably less than 20,000, more preferably 10,000 or less, and still more preferably 100 to 10,000.

(Thermosetting component (B1))
As the thermosetting component (B1), an epoxy thermosetting component is preferable.
As the epoxy thermosetting component, it is preferable to use a combination of a thermosetting agent (B12) together with a compound (B11) having an epoxy group.

Examples of the compound having an epoxy group (B11) (hereinafter, also referred to as “epoxy compound (B11)”) include polyfunctional epoxy resins, bisphenol A diglycidyl ether and hydrogenated products thereof, orthocresol novolac epoxy resins, diesters. Examples include cyclopentadiene type epoxy resins, biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenylene skeleton type epoxy resins, and other epoxy compounds having two or more functional groups.
These epoxy compounds (B11) may be used alone or in combination of two or more.

  The content of the epoxy compound (B11) is preferably 1 to 500 parts by weight, more preferably 3 to 300 parts by weight, still more preferably 10 to 150 parts by weight, and still more preferably, with respect to 100 parts by weight of the component (A). Is 20-120 parts by mass.

(Thermosetting agent (B12))
The thermosetting agent (B12) functions as a curing agent for the epoxy compound (B11).
As the thermosetting agent, a compound having two or more functional groups capable of reacting with an epoxy group in one molecule is preferable.
Examples of the functional group include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and acid anhydrides. Among these, a phenolic hydroxyl group, an amino group, or an acid anhydride is preferable, a phenolic hydroxyl group or an amino group is more preferable, and an amino group is still more preferable.

Examples of the phenolic thermosetting agent having a phenol group include polyfunctional phenolic resins, biphenols, novolac type phenolic resins, dicyclopentadiene type phenolic resins, zylock type phenolic resins, and aralkylphenolic resins.
Examples of the amine-based thermosetting agent having an amino group include dicyandiamide (DICY).
These thermosetting agents (B12) may be used alone or in combination of two or more.

  Content of a thermosetting agent (B12) becomes like this. Preferably it is 0.1-500 mass parts with respect to 100 mass parts of epoxy compounds (B11), More preferably, it is 1-200 mass parts.

(Curing accelerator (B13))
In order to adjust the speed of thermal curing of the protective film-forming film, a curing accelerator (B13) may be used. The curing accelerator (B13) is preferably used in combination with the epoxy compound (B11) as the thermosetting component (B1).

Examples of the curing accelerator (B13) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, Imidazoles such as 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; tributylphosphine, diphenylphosphine, triphenylphosphine, etc. Organic phosphines; tetraphenyl boron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.
These curing accelerators (B13) may be used alone or in combination of two or more.

  Content of a hardening accelerator (B13) is a viewpoint of the improvement of the adhesiveness of the protective film formed from the film for protective film formation, and a viewpoint of the reliability improvement of the chip | tip with a protective film manufactured using a composite sheet. To 100 parts by mass of the total amount of the epoxy compound (B11) and the thermosetting agent (B12), preferably 0.01 to 10 parts by mass, more preferably 0.1 to 6 parts by mass, and still more preferably 0.00. 3-4 parts by mass.

(Energy ray curable component (B2))
As the energy ray-curable component (B2), the compound (B21) having a functional group that reacts by irradiation with energy rays may be used alone, but the photopolymerization initiator (B22) is combined with the compound (B21). It is preferable to use it.

(Compound (B21) having a functional group that reacts upon irradiation with energy rays)
Examples of the compound (B21) having a functional group that reacts upon irradiation with energy rays (hereinafter, also referred to as “energy ray-reactive compound (B21)”) include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate. , Dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy acrylate, polyether acrylate, itacon Examples include acid oligomers.
These energy beam reactive compounds (B21) may be used alone or in combination of two or more.
In addition, the weight average molecular weight (Mw) of an energy-beam reactive compound (B21) becomes like this. Preferably it is 100-30,000, More preferably, it is 300-10,000.

  The content of the energy ray-reactive compound (B21) is preferably 1 to 1500 parts by mass, more preferably 3 to 1200 parts by mass with respect to 100 parts by mass of the component (A).

(Photopolymerization initiator (B22))
By using together with the above-mentioned energy ray-reactive compound (B21) and the photopolymerization initiator (B22), the curing of the protective film-forming film is advanced even if the polymerization curing time is shortened and the amount of light irradiation is small. be able to.
The above-mentioned thing is mentioned as a photoinitiator (B22).
The content of the photopolymerization initiator (B22) is preferably 0.1 with respect to 100 parts by mass of the energy ray-reactive compound (B21) from the viewpoint of sufficiently proceeding the curing reaction and suppressing the formation of a residue. -10 parts by mass, more preferably 1-5 parts by mass.

The content of the component (B) is preferably 5 to 50% by mass, more preferably 8 to 40% by mass, and still more preferably 10 to 30% by mass with respect to the total amount (100% by mass) of the protective film-forming film. More preferably, it is 12 to 25% by mass.
In addition, in content of (B) component, the above-mentioned epoxy compound (B11), thermosetting agent (B12), thermosetting component (B1) containing a hardening accelerator (B13), and energy beam reactivity It is the total content of the energy ray-curable component (B2) including the compound (B21) and the photopolymerization initiator (B22).

[(C) Colorant]
It is preferable that the protective film-forming film further contains (C) a colorant.
(C) A colorant is contained in the protective film-forming film, so that when a semiconductor chip having a protective film formed from the protective film-forming film is incorporated into a device, infrared rays generated from surrounding devices are shielded. Thus, malfunction of the semiconductor chip can be prevented.

(C) As the colorant, organic or inorganic pigments and dyes can be used.
As the dye, for example, any dye such as an acid dye, a reactive dye, a direct dye, a disperse dye, and a cationic dye can be used.
Moreover, it does not restrict | limit especially as a pigment, It can select from a well-known pigment suitably and can be used.
Among these, black pigments are preferable from the viewpoints of good shielding properties against electromagnetic waves and infrared rays, and further improving the discriminability by the laser marking method.
Examples of the black pigment include carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, and the like. From the viewpoint of improving the reliability of the semiconductor chip, carbon black is preferable.
In addition, you may use these (C) coloring agents individually or in combination of 2 or more types.

  The content of the component (C) is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, and still more preferably 1 with respect to the total amount (100% by mass) of the protective film-forming film. It is 0.0-15 mass%, More preferably, it is 1.2-5 mass%.

[(D) Coupling agent]
It is preferable that the protective film-forming film further contains (D) a coupling agent.
(D) By including the coupling agent, the polymer component in the protective film-forming film can be bonded to the surface of the semiconductor chip or the filler, which is the adherend, to improve adhesion and cohesion. it can. Moreover, water resistance can also be improved without impairing the heat resistance of the protective film formed from the protective film-forming film.

(D) As a coupling agent, the compound which reacts with the functional group which (A) component and (B) component have is preferable, and a silane coupling agent is more preferable.
Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxy). Propyl) trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N -Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltri Methoxysilane , Methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like.
These (D) coupling agents may be used alone or in combination of two or more.

(D) As a coupling agent, an oligomer type coupling agent is preferable.
The molecular weight of the (D) coupling agent including the oligomer type coupling agent is preferably 100 to 15000, more preferably 150 to 10,000, more preferably 200 to 5000, still more preferably 250 to 3000, and still more preferably. Is 350-2000.

  The content of the component (D) is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, and still more preferably 0 with respect to the total amount (100% by mass) of the protective film-forming film. 10 to 4% by mass, more preferably 0.15 to 2% by mass.

[(E) Inorganic filler]
It is preferable that the protective film-forming film further contains (E) an inorganic filler.
(E) By including an inorganic filler, it becomes possible to adjust the thermal expansion coefficient in the protective film after curing of the protective film-forming film to an appropriate range, and the heat of the protective film after curing with respect to the semiconductor chip. The reliability of the semiconductor device can be improved by optimizing the expansion coefficient. Moreover, it becomes possible to reduce the moisture absorption rate of the protective film after hardening.

Examples of the inorganic filler (E) include powders such as silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, and boron nitride, beads formed by spheroidizing them, single crystal fibers, and glass fibers. Can be mentioned.
These (E) inorganic fillers may be used alone or in combination of two or more.
Among these, silica or alumina is preferable.

(E) The average particle size of the inorganic filler is preferably 0.3 to 50 μm, more preferably 0.5 to 30 μm, from the viewpoint of improving the gloss value of the protective film formed from the protective film-forming film. More preferably, it is 0.7-10 micrometers.
In the present invention, the average particle diameter of the (E) inorganic filler means a value measured using a laser diffraction / scattering particle size distribution analyzer.

  The content of the component (E) is preferably 25 to 80% by mass, more preferably 30 to 70% by mass, and further preferably 40 to 65% by mass with respect to the total amount (100% by mass) of the protective film-forming film. More preferably, it is 45-60 mass%.

[(F) General-purpose additive]
In addition to the above, various additives may be added to the protective film-forming film as necessary.
Examples of the various additives include a crosslinking agent, a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion scavenger, a gettering agent, and a chain transfer agent.

<Method for producing protective film-forming film>
There is no restriction | limiting in particular as a manufacturing method of the film for protective film formation, It can manufacture by a well-known method. For example, an organic solvent is added to the raw material composition containing the above-described components to form a raw material composition solution, and the solution is applied onto the release sheet by a known coating method to form a coating film. Thereafter, the film can be dried to form a protective film-forming film on the release sheet.

Examples of the organic solvent to be used include toluene, ethyl acetate, methyl ethyl ketone and the like.
The solid concentration of the solution of the composition for forming a protective film when an organic solvent is blended is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, and still more preferably 30 to 65% by mass.
Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

The protective film-forming film of the composite sheet of the present invention may be a single layer or a multilayer structure of two or more types.
The thickness of the protective film-forming film is not particularly limited, but is preferably 3 to 300 μm, more preferably 5 to 250 μm, still more preferably 7 to 200 μm, and even when the protective film forming film has a multilayer structure, It is preferable that the total thickness is in this range.

[Physical properties and application of composite sheet for protective film formation]
The composite sheet of this invention can be manufactured by bonding the adhesive layer of the above-mentioned adhesive sheet and the protective film-forming film.

  The protective film-forming film of the composite sheet of the present invention is cured to become a protective film for the adherend. The protective film-forming film is affixed to the back side of a workpiece such as a semiconductor wafer or semiconductor chip for a face-down chip and cured by an appropriate means to replace the sealing resin. It has a function to protect the back surface. For example, when affixed to a semiconductor wafer, the protective film has a function of reinforcing the wafer, so that damage to the wafer can be prevented.

In addition, the composite sheet of the present invention can be used as a sheet for fixing a workpiece such as a semiconductor wafer during blade dicing, eliminating the need for dicing by separately attaching a dicing sheet and simplifying the manufacturing process of the semiconductor device. Can be
In addition, the composite sheet of the present invention is formed by a so-called tip dicing method (a groove deeper than the thickness of the chip to be obtained is formed on the semiconductor wafer from the circuit surface side, and is thinned from the back surface side of the semiconductor wafer at least until the groove is reached. Can be used in a method of obtaining a chip group by carrying out the separation process, or may be used by being attached to a chip group separated into individual pieces.

  The protective film-forming composite sheet of the present invention does not peel off the protective film-forming film from the protective film-forming composite sheet after affixing the protective film-forming film of the protective film-forming composite sheet to a workpiece. Furthermore, when the protective film-forming film is cured under the conditions of 130 ° C. and 2 hours to form the protective film, the gloss value of the protective film is high. The gloss value of the protective film is preferably 40 or more, more preferably 44 or more.

[Chip with protective film]
The chip with a protective film of the present invention has a protective film formed by bonding the composite sheet of the present invention to the surface of a chip such as a semiconductor chip and curing the protective film-forming film of the composite sheet.
The protective film of the chip with a protective film of the present invention may be completely cured, or may be partially cured, but is preferably completely cured.

About the protective film which the chip | tip with a protective film of this invention has, the gross value of the protective film measured from the opposite side to the chip | tip side with the chip | tip with a protective film becomes like this. Preferably it is 40 or more, More preferably, it is 44 or more, , Preferably 90 or less. If the gloss value is 40 or more, a chip with a protective film excellent in laser marking suitability can be obtained.
In addition, you may measure the gloss value of the protective film of the chip | tip with a protective film using the workpiece | work with the protective film before dicing which performed the hardening process and formed the protective film like the below-mentioned Example.
Protecting workpieces with protective film measured from the side opposite to the side with the protective film tip, measured from the side opposite to the side with the protective film. The gross value of the film is considered to be almost the same.

  A chip with a protective film can be mounted on a substrate or the like by a face-down method to manufacture a semiconductor device. Moreover, a semiconductor device can also be manufactured by adhere | attaching the chip | tip with a protective film on other members (on a chip mounting part), such as a die pad part or another semiconductor chip.

[Method of manufacturing chip with protective film]
Although there is no restriction | limiting in particular as a manufacturing method of the chip | tip with a protective film of this invention, For example, the method by a blade dicing which has the following process (1)-(4) is preferable.
Step (1): Step of attaching the composite sheet for forming a protective film of the present invention to the back surface of the work Step (2): Step of dicing the work Step (3): Peeling the adhesive sheet of the composite sheet for forming the protective film Step (4) of curing the protective film forming film without picking up: Picking up the diced workpiece with protective film obtained through steps (1) to (3) to obtain a chip with protective film

  In addition, in the manufacturing method of the chip | tip with a protective film of this invention, the order of process (1), (2), (3), (4) may be sufficient regardless of the order of process (2) and (3), You may manufacture a chip | tip with a protective film in order of process (1), (3), (2), (4).

<Step (1)>
In the step (1), the protective film-forming film of the composite sheet of the present invention is attached to the back surface of the work such as a semiconductor wafer to obtain a work with the protective film-forming film.
Here, the semiconductor wafer may be a silicon wafer or a compound semiconductor wafer such as gallium / arsenic. Further, the semiconductor wafer may have a circuit formed on the front surface thereof, the back surface thereof appropriately ground or the like, and a thickness of about 50 to 500 μm.

<Step (2)>
In the step (2), the work is diced, the circuit formed on the work surface is diced, and the work is processed into chips.
In addition, the workpiece | work which is the target object which carries out dicing at this process may be a workpiece | work with the film for protective film formation obtained through the process (1), and after a process (1), a process (3) previously. It may be a workpiece with a protective film obtained through.
The workpiece dicing can be performed by a known method.

  In this step, the composite sheet of the present invention is excellent in adhesion between the pressure-sensitive adhesive layer and the protective film-forming film (protective film), and therefore between the pressure-sensitive adhesive layer and the protective film-forming film (protective film). In addition, the phenomenon that the cutting water enters can be effectively suppressed. Therefore, according to the method for manufacturing a chip with a protective film of the present invention, it is possible to manufacture a chip with a protective film in which the protective film is not contaminated with cutting water while improving the productivity.

Here, after this step (1), when this step is performed, a diced workpiece with a protective film-forming film is obtained, and in the next step (3), the protective film-forming film is cured, The workpiece with a protective film is diced.
On the other hand, when the step (3) is passed after the step (1), the workpiece with the protective film obtained in the step (3) is diced in this step to obtain a diced workpiece with the protective film.

<Step (3)>
Step (3) is a step of forming a cured protective film by curing the protective film-forming film without peeling off the adhesive sheet of the protective film-forming composite sheet.
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the protective film-forming composite sheet attached to the work is kept low in fluidity during heating.
Therefore, in the production method of the present invention, the pressure-sensitive adhesive of the pressure-sensitive adhesive sheet can be cured even if heat is applied by curing the film for forming a protective film without peeling off the pressure-sensitive adhesive sheet of the composite sheet for forming a protective film attached to the workpiece. The smoothness of the surface of the layer is maintained, and a protective film having a gloss value of 40 or more can be formed.

Curing of the protective film-forming film can be performed by heating, irradiation with energy rays, or both depending on the type of curable component contained in the protective film-forming film. However, from the viewpoint of suppressing coloring of the protective film formed from the protective film-forming film, from the viewpoint of sufficiently proceeding the curing reaction, and from the viewpoint of cost reduction, it is preferable to perform at least heating.
As the conditions for curing by heating, the curing temperature is preferably 100 to 150 ° C., and the curing time is preferably 1 to 3 hours.
Moreover, conditions for curing by irradiation with energy rays are appropriately set depending on the type of energy rays to be used. For example, when ultraviolet rays are used, the illuminance is preferably 170~250mw / cm ^2, light quantity is preferably 600~1000mJ / cm ^2.

<Process (4)>
In step (4), the diced workpiece with protective film obtained through steps (1) to (3) is picked up by a general-purpose means such as a collet to obtain a chip with protective film.
By passing through this process, the individualized semiconductor chip (chip with a protective film) which has a protective film on the back surface is obtained.
In general, when this step is performed after thermosetting in step (3), pickup tends to be difficult. In contrast, the method for producing a chip with a protective film of the present invention has a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition containing a specific energy ray-curable acrylic copolymer, so that pick-up suitability is improved, and the protective film The productivity of the attached chip can be improved.

The chip with a protective film obtained by the production method of the present invention can be a chip with a protective film having excellent laser marking suitability because the gloss value of the protective film is high.
About the chip | tip with a protective film obtained by the manufacturing method of this invention, the gross value of the protective film measured from the opposite side to the chip | tip side of a chip | tip with a protective film becomes like this. Preferably it is 40 or more, More preferably, it is 44 or more.

  In the following description, the weight average molecular weight (Mw) and glass transition temperature (Tg) of each component are values measured or calculated by the method shown below.

<Weight average molecular weight (Mw)>
Using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name “HLC-8220GPC”), measurement was performed under the following conditions, and values measured in terms of standard polystyrene were used.
(Measurement condition)
・ Column: “TSK guard column HXL-H” “TSK gel GMHXL (× 2)” “TSK gel G2000HXL” (both manufactured by Tosoh Corporation)
-Column temperature: 40 ° C
・ Developing solvent: Tetrahydrofuran ・ Flow rate: 1.0 mL / min

<Glass transition temperature (Tg)>
The value calculated by the above equation (1) was used.

Production Example 1 (Preparation of protective film-forming film)
(1) Preparation of solution of raw material composition for protective film-forming film The following components (A) to (F) are added in the amounts shown below, diluted with methyl ethyl ketone, and a protective film having a solid content concentration of 61% by mass. A raw material composition solution of a forming film was prepared.
<(A) Polymer component>
An acrylic copolymer (BA / MMA / GMA / HEA = 55/10/20) composed of n-butyl acrylate (BA), methyl methacrylate (MMA), glycidyl methacrylate (GMA), and 2-hydroxyethyl acrylate (HEA) / 15 (mass%), Mw: 900,000, Tg: -28 ° C): 100 parts by mass (solid content ratio).
<(B) Curing component>
-Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name “jER828”, epoxy equivalent: 180 to 200, molecular weight: 370 (compound having a weight average molecular weight of less than 20,000)): 50 parts by mass (solid content ratio) ).
-Dicyclopentadiene type epoxy resin (Dainippon Ink Chemical Co., Ltd., trade name "Epicron HP-7200HH", compound having a weight average molecular weight of less than 20,000): 50 parts by mass (solid content ratio).
Dicyandiamide (trade name “ADEKA HARDNER 3636AS” manufactured by ADEKA Corporation, amine-based curing agent): 2.8 parts by mass (solid content ratio).
-2-Phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name “Cureazole 2PHZ”, curing accelerator): 2.8 parts by mass (solid content ratio).
<(C) Colorant>
Carbon black: 10 parts by mass (solid content ratio).
<(D) Silane coupling agent>
A-1110 (trade name, manufactured by Nippon Unicar Co., Ltd.): 1 part by mass (solid content ratio).
<(E) Inorganic filler>
-Fused silica (average particle size 8 μm): 300 parts by mass (solid content ratio).

(2) Production of protective film-forming film The prepared raw material composition solution was dried on the release-treated surface of a release sheet (trade name “SP-PET3811”, thickness: 38 μm, manufactured by Lintec Corporation). Was applied to a thickness of 25 μm and dried at 120 ° C. for 2 minutes to form a protective film-forming film on the release sheet.
Then, on this formed film for forming a protective film, a release treatment surface of another release sheet (product name “SP-PET381031”, thickness: 38 μm, manufactured by Lintec Corporation) is bonded, and sandwiched between two release sheets. A film for forming a protective film having a thickness of 25 μm was prepared.

Examples 1-3, Comparative Examples 1-4
(1) Preparation of solution of pressure-sensitive adhesive composition Each component of the type and blending amount shown in Table 2 was added and diluted with ethyl acetate to prepare a pressure-sensitive adhesive composition solution having a solid content concentration of 24% by mass. Details of each component are as follows.

<Acrylic copolymer>
Methacryloyloxyethyl acrylate is added to the acrylic polymer derived from the raw material monomer in the types and proportions shown in Table 1 at a blending amount shown in Table 1, and 25 ° C. using dibutyltin laurate as a catalyst under an ethyl acetate solution. Acrylic copolymers A1 to A7 synthesized by reacting at normal pressure for 24 hours were used.
In Table 1, Tg is the glass transition temperature of the acrylic polymer, and Mw is the weight average molecular weight of the acrylic copolymer obtained by reacting with methacryloyloxyethyl acrylate. The acrylic copolymers A1 to A6 are energy ray curable acrylic copolymers having a methacryloyl group.

<Photopolymerization initiator>
Irgacure 184: trade name (“Irgacure” is a registered trademark), manufactured by BASF, 1-hydroxycyclohexyl phenyl ketone.
<Crosslinking agent>
BHS-8515: trade name, manufactured by Toyo Ink Manufacturing Co., Ltd., a tolylene diisocyanate compound.
<Polymerizable composition>
UV-5806: a polymerizable composition containing a trade name, manufactured by Nippon Synthetic Chemical Co., Ltd., 10 functional urethane acrylate (Mw: 1740) and a photopolymerization initiator.

(2) Preparation of pressure-sensitive adhesive sheet A solution of the prepared pressure-sensitive adhesive composition was applied onto the release-treated surface of a release sheet (trade name “SP-PET3811”, thickness: 38 μm, manufactured by Lintec Corporation) and the coating amount after drying was It is applied so as to be 10 g / m ² , dried at 100 ° C. for 1 minute to form an adhesive layer on the release sheet, and a 100 μm-thick polypropylene as a base material on the adhesive layer A film (trade name “CT265” manufactured by Mitsubishi Plastics, Inc.) was laminated.
Then, ultraviolet rays (illuminance 140 mW / cm ² , light amount 510 mJ / cm ² ) are irradiated from the release sheet side using an ultraviolet irradiation device (product name “RAD-2000m / 12” manufactured by Lintec Corporation), and the pressure-sensitive adhesive layer The entire surface was cured to produce an adhesive sheet having an adhesive layer including a cured region.

(3) Production of Composite Sheet for Protective Film Formation A protective film sandwiched between the two release sheets produced in Production Example 1 on the cured region of the pressure-sensitive adhesive layer that was exposed by removing the release sheet from the produced adhesive sheet. After the protective film-forming film that had been exposed by removing one release sheet of the forming film was directly laminated, the remaining release sheet was also removed to expose the protective film-forming film.
A double-sided pressure-sensitive adhesive tape having a release sheet on both sides (trade name “Adwill G” manufactured by Lintec Co., Ltd.) is used as a member for forming a jig adhesive layer to be affixed to the ring frame portion on the surface of the protective film-forming film. −01DF ”), one release sheet of the double-sided pressure-sensitive adhesive sheet extracted into a circular shape having a diameter of 245 mm was removed, and the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet and the protective film forming layer were laminated. Further, in accordance with the outer diameter (diameter 270 mm) of the margin for the ring frame, it was die-cut in a circular shape so as to be concentric with the circular portion extracted from the double-sided adhesive tape, as shown in FIG. A composite sheet for forming a protective film having a configuration was prepared.

  The composite film for forming a protective film produced as described above was evaluated by the following method. The evaluation results are shown in Table 2.

(1) Intrusion of cutting water during dicing Thickness 200 μm, diameter 8 inches, polishing surface of silicon wafer subjected to # 2000 polishing, and protective film formation of composite sheet for protective film formation produced in Examples and Comparative Examples The film for application was attached while being heated to 70 ° C. using an adhesive sheet attaching apparatus (product name “Adwill RAD2700” manufactured by Lintec Corporation). At the same time, a ring frame was also attached.
And the wafer which stuck the composite sheet for protective film formation was thrown into the 130 degreeC heating oven for 2 hours, the film for protective film formation was hardened, and the protective film was formed.
Then, using a dicer (manufactured by Disco Corporation, product name “DFD651”), the base material of the composite sheet for protective film formation was cut to a depth of 15 μm at a blade speed of 40 mm / sec. The wafer was diced into chips of the size.
Then, it was observed visually whether there was intrusion of cutting water between a protective film and an adhesive layer from a cutting part.
Table 2 shows the number of wafers in which cutting water does not enter due to insufficient sticking to the wafer after the above operation is performed on 30 wafers.

(2) Pickup suitability After using a 3 mm × 3 mm size chip prepared in the evaluation of “(1) Presence or absence of water intrusion during dicing” as a sample obtained by dicing a wafer and performing an expansion with a withdrawal amount of 3 mm, Using a die bonder (product name “Bestem-D02” manufactured by Canon Machinery Inc.), 50 chips were picked up.
Table 2 shows the number of picked up chips for 50 chips.

(3) Gloss value Adhesive sheet pasting the polished surface of a # 2000 polished silicon wafer (diameter 200 mm, thickness 280 μm) and the protective film forming film of the protective film forming composite sheet prepared in Examples and Comparative Examples Using an apparatus (product name “Adwill RAD-2700”, manufactured by Lintec Corporation), it was attached while heating to 70 ° C.
Then, the wafer with the protective film-forming composite sheet attached is placed in a heating oven at 130 ° C. for 2 hours to cure the protective film-forming film, form a protective film, and attach the adhesive sheet on the formed protective film. Removed to make a test sample.
Then, using a gloss meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name “VG 2000”), according to JIS Z 8741, the surface of the protective film is 60 degrees from the side opposite to the side where the silicon wafer is present. The specular gloss was measured, and the measured value was defined as the gloss value of the protective film.

(4) Applicability to laser marking Adhesion of the polished surface of a silicon wafer having a thickness of 200 μm, a diameter of 8 inches, and # 2000 polishing to the protective film-forming film of the composite sheet for protective film formation prepared in Examples and Comparative Examples Using a sheet sticking apparatus (product name “Adwill RAD2700” manufactured by Lintec Corporation), the sticking was performed while heating to 70 ° C. At the same time, a ring frame was also attached.
And the wafer which stuck the composite sheet for protective film formation was thrown into the 130 degreeC heating oven for 2 hours, the film for protective film formation was hardened, and the protective film was formed.
Next, using a laser marker (manufactured by Hitachi Construction Machinery Finetech Co., Ltd., product name “YAG Laser Marker LM5000”), characters of 400 μm length and 200 μm width were printed on the protective film from the base material side of the adhesive sheet. .
And after removing the adhesive sheet of the composite sheet for protective film formation, the characters printed on the protective film were observed with the naked eye and evaluated according to the following criteria.
A: Characters are clear.
F: Characters are unclear.

When manufacturing a chip with a protective film using the composite sheet for forming a protective film in Examples 1 to 3, no cutting water entered between the protective film and the adhesive layer during dicing, and the pickup suitability is also good. Met.
Moreover, the gross value of the protective film measured from the opposite side to the wafer side of the wafer with the protective film manufactured using the composite sheet for forming the protective film of Examples 1 to 3 was high. Therefore, the gloss value of the protective film measured from the side opposite to the side where the chip of the chip with the protective film manufactured using the composite sheet for forming the protective film of Examples 1 to 3 is high is also high. The laser marking aptitude is considered excellent.
On the other hand, when a chip with a protective film was manufactured using the composite sheet for forming a protective film of Comparative Examples 1, 2, and 4, although no penetration of cutting water was observed between the protective film and the adhesive layer, the pickup The result was inferior in suitability. Moreover, when a chip with a protective film was produced using the composite sheet for forming a protective film of Comparative Example 3, the penetration of cutting water was observed between the protective film and the adhesive layer, although the pickup suitability was good. .
Furthermore, the gross value of the protective film measured from the opposite side of the wafer with the protective film manufactured using the protective film-forming composite sheets of Comparative Examples 1 to 4 is higher than that of Examples 1 to 3. The result was low. Therefore, it is thought that the laser marking aptitude of the chip with a protective film manufactured using the composite sheet for forming a protective film of Comparative Examples 1 to 4 is inferior.

  The composite sheet for forming a protective film of the present invention is suitable as a protective film forming material for protecting the back surface of the semiconductor chip.

1a, 1b, 1c, 1d, 2a, 2b, 2c Protective film forming composite sheet (composite sheet)
DESCRIPTION OF SYMBOLS 10, 10a Adhesive sheet 11 Base material 11a Base material side 12 Adhesive layer 12a Curing area 13 Energy ray shielding layer 20 Protective film forming film 31 Jig adhesion layer 41 Jig adhesion adhesive layer

Claims (10)

A protective film-forming composite sheet comprising a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, and a protective film-forming film laminated directly on the pressure-sensitive adhesive layer,
The pressure-sensitive adhesive composition containing an energy ray-curable acrylic copolymer in which the pressure-sensitive adhesive layer introduces an energy ray-polymerizable group into an acrylic polymer (X) containing 10% by mass or more of a structural unit (x1) derived from methyl methacrylate. Ri layer der made formed from the object,
A composite sheet for forming a protective film, which is used by being affixed to the back surface of a workpiece, which is the surface opposite to the circuit surface of the workpiece .   The composite sheet for protective film formation of Claim 1 which has the structure which formed the hardening area | region which at least one part of the said adhesive layer hardened | cured, and the said film for protective film formation was directly laminated | stacked on the said hardening area | region.   The composite sheet for forming a protective film according to claim 1 or 2, wherein the energy beam polymerizable group is a (meth) acryloyl group.   Polymerization in which the energy ray curable acrylic copolymer has an energy ray polymerizable group in an acrylic polymer (X) containing a structural unit (x1) derived from methyl methacrylate and a structural unit (x2) derived from a functional group-containing monomer. The composite sheet for protective film formation as described in any one of Claims 1-3 which is an acrylic copolymer obtained by making a reactive compound (Y) react. The composite sheet for forming a protective film according to claim 4, wherein the value of α calculated from the following formula (2) of the energy ray curable acrylic copolymer is 20 or less.
Formula (2): α = [P] × [Q] × [R] / 100
[In Formula (2), [P] shows the content rate of the structural unit (x2) derived from a functional group containing monomer with respect to 100 mass parts of all the structural units of acrylic polymer (X). [Q] represents the equivalent of the polymerizable compound (Y) to 100 equivalents of the functional group derived from the functional group-containing monomer of the acrylic polymer (X). [R] represents the number of energy ray polymerizable groups of the polymerizable compound (Y). ]   The protective film-forming composite sheet according to any one of claims 1 to 5, wherein the protective film-forming film comprises (A) a polymer component and (B) a curable component.   The composite sheet for forming a protective film according to claim 6, wherein the (B) curable component comprises (B1) a thermosetting component.   After affixing the protective film-forming film of the protective film-forming composite sheet to a workpiece, without peeling the protective film-forming film from the protective film-forming composite sheet, at 130 ° C. for 2 hours. The protective film-forming composite sheet according to claim 7, wherein when the protective film is cured to form a protective film, the protective film has a gloss value of 40 or more.   The composite sheet for protective film formation according to any one of claims 1 to 8, wherein the base material is a base material containing polypropylene. The manufacturing method of the chip | tip with a protective film which has following process (1)-(4).
Step (1): Step of attaching the composite sheet for forming a protective film according to any one of claims 1 to 9 to the back surface of the workpiece Step (2): Step of dicing the workpiece Step (3): The protection Step of curing the protective film-forming film without peeling off the adhesive sheet of the composite sheet for film formation (4): Picking up the diced workpiece with protective film obtained through the steps (1) to (3) , Process for obtaining chip with protective film