JP2017008255A - Composite sheet for forming protective film, tip with protective film and manufacturing method of tip with protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite sheet for forming a protective film capable of manufacturing a tip with the protective film high in suppression effect on phenomenon that cutting water is infiltrated between a film for forming the protective film (protection film) and an adhesive layer when used during dicing of work such as a wafer.SOLUTION: There is provided a composite sheet for forming a protective film having an adhesive sheet with a substrate and an adhesive layer and a film for forming the protective film directly laminated on the adhesive layer, where the adhesive layer is formed from an adhesive composition containing an energy ray curable acryl copolymer, the energy ray curable acryl copolymer is an acryl copolymer obtained by reacting an acrylic polymer (X) containing a constitutional unit derived from a functional group-containing monomer (x2) of 35 mass% or less with a polymerizable compound (Y) having an energy ray polymerizable group and having the energy ray polymerizable group introduced and a value of α calculated from the formula (2) of the energy ray curable acryl copolymer of 28 or less. Formula (2):α=[P]×[Q]×[R]/100.SELECTED DRAWING: None

Description

  The present invention can form a protective film on the back surface of a workpiece such as a semiconductor wafer or semiconductor chip, and can improve the manufacturing efficiency of the semiconductor chip, and can form the protective film 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 then 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 the liquid resin in this way is not sufficient, there is often a problem that the yield of the obtained chip with the protective film is lowered.

  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 formed of 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 can be noticeable. 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, the 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 the productivity is remarkably improved.
In the method described 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 dicing sheet in which a protective film-forming film such as the protective film-forming layer described above is laminated on the adhesive layer of the adhesive sheet, including the protective film-forming and dicing sheet having the above-described configuration, When dicing the wafer to which the sheet is attached, there is a problem that cutting water enters between the protective film-forming film (protective film) and the pressure-sensitive adhesive layer, thereby contaminating the manufactured chip with the protective film. .

  INDUSTRIAL APPLICABILITY The present invention can manufacture a chip with a protective film that is highly effective in suppressing the phenomenon that cutting water enters between a protective film-forming film (protective film) and an adhesive layer when used when dicing a workpiece such as a wafer. It is an object to provide a composite sheet for forming a protective film, a chip with a protective film, and a method for manufacturing a chip with a protective film.

  The present inventors form the pressure-sensitive adhesive layer of the composite sheet for forming a protective film from a pressure-sensitive adhesive composition containing an energy ray-curable acrylic polymer having specific characteristics into which an energy ray polymerizable group is introduced. Thus, the inventors have found that the above problems can be solved and completed the present invention.

That is, the present invention provides the following [1] to [12].
[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, wherein the pressure-sensitive adhesive layer is an energy ray curable type An acrylic polymer, which is a layer formed from a pressure-sensitive adhesive composition containing an acrylic copolymer, wherein the energy ray-curable acrylic copolymer contains a functional group-containing monomer-derived structural unit (x2) of 35% by mass or less. (X) is an acrylic copolymer into which an energy beam polymerizable group is introduced, obtained by reacting a polymerizable compound (Y) having an energy beam polymerizable group, of the energy beam curable acrylic copolymer The composite sheet for protective film formation whose value of (alpha) computed from following formula (2) is 28 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 an equivalent amount of the polymerizable compound (Y) with respect 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). ]
[2]. The composite sheet for forming a protective film according to [1], wherein the acrylic polymer (X) contains 10% by mass or more of a structural unit (x1) derived from methyl methacrylate.
[3]. For forming a protective film according to [1] or [2], 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.
[4]. The composite sheet for forming a protective film according to any one of [1] to [3], wherein the energy ray polymerizable group is a (meth) acryloyl group.
[5]. The composite sheet for forming a protective film according to any one of [1] to [4], wherein the film for forming a protective film includes (A) a polymer component and (B) a curable component.
[6]. (B) The protective film-forming composite sheet according to [5], wherein the curable component comprises (B1) a thermosetting component.
[7]. 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 film according to any one of [1] to [6], wherein when the protective film is cured to form a protective film, the protective film has a gloss value of 40 or more. Composite sheet.
[8]. The composite sheet for forming a protective film according to any one of [1] to [7], wherein the base material is a base material containing polypropylene.
[9]. The chip | tip with a protective film which has a protective film formed by hardening | curing the protective film formation film of the composite sheet for protective film formation as described in any one of [1]-[8] on the back surface of a chip | tip.
[10]. The chip with protective film according to [9], wherein the gloss value of the protective film measured from the side opposite to the side with the chip of the chip with protective film is 40 or more.
[11]. The manufacturing method of the chip | tip with a protective film which has following process (1)-(4).
Process (1): The process of sticking the composite sheet for protective film formation as described in any one of [1]-[8] to the back surface of a work process (2): The process of dicing a work process (3): The process of hardening the film for protective film formation, without peeling the adhesive sheet of the said composite sheet for protective film formation Process (4): The dicing workpiece | work with a protective film obtained through steps (1)-(3) Step of picking up and obtaining a chip with a protective film [12]. [11] A chip with a protective film obtained by the manufacturing method according to [11], wherein the gloss value of the protective film measured from the opposite side of the chip with the protective film is 40 or more Chip.

  By using the composite sheet for forming a protective film of the present invention at the time of dicing a workpiece such as a wafer, the effect of suppressing the phenomenon that cutting water enters between the protective film-forming film (protective film) and the adhesive layer is obtained. A chip with a high protective film can be manufactured.

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.

〔上記式（１）中、Ｗ_１、Ｗ_２、Ｗ_３、Ｗ_４・・・は、樹脂を構成するモノマー成分の質量分率（質量％）を示し、Ｔｇ_１、Ｔｇ_２、Ｔｇ_３、Ｔｇ_４・・・は、樹脂を構成するモノマー成分のホモポリマーの絶対温度（Ｋ）表示のガラス転移温度を示す。〕

[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”) is a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, and a protective film-forming film directly laminated on the pressure-sensitive adhesive layer; It is what has.
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 includes the protective film-forming film 20 having substantially the same shape as the workpiece such as a semiconductor wafer or the entire shape of the workpiece when viewed in plan from the protective film-forming film 20 side. It may be configured as a composite sheet 1b adjusted to a shape that can be used, and is configured as a composite sheet 1a that is laminated on a pressure-sensitive adhesive sheet 10 that is larger than the protective film-forming film 20. Also good.

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 a position where at least the protective film-forming film 20 of the pressure-sensitive adhesive layer 12 is laminated, and the entire region of the pressure-sensitive adhesive layer 12 is cured, so that the entire region in the pressure-sensitive adhesive layer 12 is A hardened region may be formed over the entire area.

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 used in chip production 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.

The cured region 12a preferably has the same shape as the protective film forming film 20 in plan view, but is larger than the protective film forming film 20 and includes the entire protective film forming film 20. May be.
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 it is particularly preferable that the curing is complete.
Irradiation of energy rays may be performed from the substrate 11 side, or may be performed from the protective film forming film 20 side, and energy beam irradiation is performed before the protective film forming film 20 and the adhesive sheet are bonded together. Alternatively, it may be performed from the side of the surface to be bonded to the protective film forming film 20.
Further, as in the composite sheet 1d in FIG. 1D, an energy ray shielding layer 13 is provided by printing or the like at a part of the boundary between the base material 11 and the pressure-sensitive adhesive layer 12, and energy rays are applied 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.

Further, 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.
Further, in the composite sheet 2b of FIG. 2B, the protective film-forming film 20 and the pressure-sensitive adhesive sheet 10 have the same shape in plan view, and a jig is formed on the outer peripheral portion of the surface of the protective film-forming film 20. The adhesive layer 31 is provided. 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, the composite sheet 2a in FIG. 2A and the composite sheet 2b in FIG. 2B also form a cured region at a position where at least the protective film forming film 20 of the pressure-sensitive adhesive layer 12 is laminated for the above-described reason. It is preferable that the entire region of the pressure-sensitive adhesive layer 12 is cured, and a cured region may be formed over the entire region in the pressure-sensitive adhesive layer 12.

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.
Further, as the pressure-sensitive adhesive used for forming the jig bonding layer 31, according to the classification according to the function of the pressure-sensitive adhesive, for example, an energy ray curable pressure-sensitive adhesive, a pressure-sensitive adhesive, a thermally expandable pressure-sensitive adhesive, etc. According to the classification based on the main resin in the pressure-sensitive adhesive, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a vinyl ether-based pressure-sensitive adhesive, 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 is separated from the pressure-sensitive adhesive layer 12 between the base material 11 and the pressure-sensitive adhesive layer 12, in addition to the pressure-sensitive adhesive layer 12 directly laminated with the protective film forming film 20. The jig adhesive pressure-sensitive adhesive layer 41 is provided. That is, the composite sheet 2c has a pressure-sensitive adhesive sheet 10a in which a base material 11, a jig bonding pressure-sensitive adhesive layer 41, and a pressure-sensitive adhesive layer 12 are laminated in this order.
By providing the jig bonding pressure-sensitive adhesive layer 41, the area where the pressure-sensitive adhesive layer 12 is not present and the jig such as a ring frame are bonded to each other when the jig bonding pressure-sensitive adhesive layer 41 is viewed in plan. In doing so, 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, it is preferable that the composite sheet 2c of FIG.2 (c) also has the hardening area | region formed in the position which the film 20 for protective film formation of the adhesive layer 12 laminates | stacks for the above-mentioned reason. The whole area | region of this may be hardened | cured and the hardening area | region may be formed over the whole area | region in the adhesive layer 12. FIG.

Examples of the pressure-sensitive adhesive that forms the jig-bonding pressure-sensitive adhesive layer 41 include the same pressure-sensitive adhesive as that used to form the jig-bonding layer 31 described above. An adhesive 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 exposed without being laminated, the surface of the jig adhesive layer 31, and the adhesive A release sheet may be further provided on the surface of the pressure-sensitive adhesive layer 41 for jig bonding that is exposed without the 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, for example.
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 thermoset before being peeled off from the pressure-sensitive adhesive sheet, by using a resin film having excellent heat resistance as the 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 layer formed from a pressure-sensitive adhesive composition containing an energy ray curable acrylic copolymer. And the said energy-beam curable acrylic copolymer is a polymeric compound (Y which has an energy-beam polymerizable group in acrylic polymer (X) which contains 35 mass% or less of structural units (x2) derived from a functional group containing monomer. ) Is introduced, and an energy beam polymerizable group is introduced.

  In addition to the energy ray curable acrylic copolymer, the pressure-sensitive adhesive composition preferably contains a photopolymerization initiator from the viewpoint of efficiently proceeding a curing reaction in a short time. 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.

  Note that 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 as in the configuration of the composite sheets 1c and 1d shown in FIGS. 1 (c) and (d). Is preferred.

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 a polymerizable compound having an energy ray polymerizable group in an acrylic polymer (X) containing 35% by mass or less of a structural unit (x2) derived from a functional group-containing monomer ( It is an acrylic copolymer into which an energy ray polymerizable group is introduced, obtained by reacting Y).
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 ray polymerizable group may be directly bonded to the acrylic polymer (X), or the acrylic polymer (X) via a linking group such as an alkylene group, an alkyleneoxy group, or a polyalkyleneoxy group. ).

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, particularly preferably 400,000 to 80. It is ten thousand.
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 1.5 million or less, the adhesiveness between the pressure-sensitive adhesive layer and the protective film-forming film is further improved, and cutting water enters between the pressure-sensitive adhesive layer and the protective film-forming film during dicing. The phenomenon can be suppressed to a higher degree.

  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%, Most preferably, it is 90-98 mass%.

  In the energy ray curable acrylic copolymer, the acrylic polymer (X) and the group possessed by the polymerizable compound (Y) react to form a polymer on the main chain and / or side chain of the acrylic polymer (X). An energy beam polymerizable group possessed by the conductive compound (Y) is introduced. Hereinafter, the acrylic polymer (X) and the polymerizable compound (Y) will be described.

(Acrylic polymer (X))
The acrylic polymer (X) contains 35 mass% or less of the structural unit (x2) derived from the functional group-containing monomer.
By using the acrylic polymer (X) containing 35% by mass or less of the structural unit (x2) derived from the functional group-containing monomer, good adhesion between the formed pressure-sensitive adhesive layer and the protective film-forming film can be maintained. it can. As a result, when the obtained composite sheet is used for chip manufacture, it is possible to suppress a phenomenon in which cutting water enters between the protective film-forming film (protective film) and the adhesive layer during dicing.

The functional group that the structural unit (x2) has reacts with the group that the polymerizable compound (Y) has.
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 (a group having a nitrogen atom as an atom constituting a ring skeleton), and an alkoxysilyl group. Etc.

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-containing monomer. Examples include a monomer having a 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 group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl. Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylate and 4-hydroxybutyl (meth) acrylate; 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, itaconic acid, and the like.

Examples of the epoxy group-containing monomer include epoxy group-containing (meth) acrylic acid esters and non-acrylic epoxy group-containing monomers.
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 mass%, more preferably 5 to 35 mass%, still more preferably 7 with respect to the total structural units (100 mass%) of the acrylic polymer (X). It is -33 mass%, Most preferably, it is 10-33 mass%. And the upper limit of the said content rate of a structural unit (x2) can also be selected from either 27 mass%, 25 mass%, 23 mass%, etc., for example.
If the said content rate of a structural unit (x2) is 1 mass% or more, the reactive point with the polymeric compound (Y) of acrylic polymer (X) will increase, and the additional amount of polymeric compound (Y) will be increased. Can be increased. As a result, a pressure-sensitive adhesive layer with higher curability can be formed.
On the other hand, if the said content rate of a structural unit (x2) is 35 mass% or less, it will suppress that the hydrophilic degree of the adhesive layer formed becomes large too much, and an adhesive layer and the film for protective film formation ( It is possible to prevent the phenomenon that cutting water enters between the protective film and the protective film. Moreover, sufficient pot life can be ensured in the step of applying the solution of the pressure-sensitive adhesive composition as a coating solution to form the pressure-sensitive adhesive layer.

  In addition to the structural unit (x2) derived from the functional group-containing monomer, the acrylic polymer (X) may further include a structural unit (x1) derived from methyl methacrylate. That is, 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 acrylic copolymer obtained by making the polymeric compound (Y) to have may react.

When the acrylic polymer (X) includes the structural unit (x1), the content ratio of the structural unit (x1) is preferably 10 masses with respect to all the structural units (100% by mass) of the acrylic polymer (X). % Or more, more preferably 10 to 80% by mass, further preferably 15 to 75% by mass, particularly preferably 20 to 70% by mass, particularly preferably 25 to 65% by mass, and most preferably 27 to 60% by mass.
When the content of the structural unit (x1) is 10% by mass or more, the flowability during heating is kept low for the pressure-sensitive adhesive layer to be formed, and the pressure-sensitive adhesive is used when the protective film-forming film is heat-cured. The smoothness of the surface of the layer can be maintained, and the gloss value of the 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 production, 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.

The acrylic polymer (X) is derived from an alkyl (meth) acrylate other than methyl methacrylate from the viewpoint of improving the adhesiveness of the adhesive layer and further improving the adhesion between the adhesive layer and the protective film-forming film. It is preferable that the structural unit (x3) is included.
The alkyl (meth) acrylate constituting the structural unit (x3) is not particularly limited as long as it is a monomer copolymerizable with the functional group-containing monomer and methyl methacrylate, and may be, for example, methyl acrylate. From the viewpoint of improving the adhesiveness of the adhesive layer and further improving the adhesion between the adhesive layer and the protective film-forming film, it has an alkyl (meth) acrylate having a C 2-18 alkyl group, or a cyclic skeleton. (Meth) acrylate is preferred, and alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms is more preferred. In the present specification, the “alkyl group” of the “alkyl (meth) acrylate” means an alkyl group constituting an alkyl ester unless otherwise specified.
Carbon number of the alkyl group which alkyl (meth) acrylate has becomes like this. 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, pentyl (meth) acrylate, hexyl (meth) acrylate, Heptyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl ( (Meth) acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (medium) ) Acrylate, hexadecyl (meth) acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (stearyl (meth) acrylate), isooctadecyl (meth) acrylate (isostearyl (meth) acrylate), etc. Is mentioned.
Examples of the (meth) acrylate having a cyclic skeleton include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyl. Examples thereof include oxyethyl (meth) acrylate and imide acrylate.
These monomers may be used independently and may be used in combination of 2 or more type.
Among these, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable from the viewpoint of improving the adhesiveness of the adhesive layer and further improving the adhesion between the adhesive layer and the protective film-forming film. 2-Ethylhexyl (meth) acrylate is more preferred.

  The content ratio of the structural unit (x3) is preferably 10 to 85% by mass, more preferably 15 to 85% by mass, still more preferably 20 to 83% by mass, with respect to all the structural units of the acrylic polymer (X). Most preferably, it is 25-83 mass%. And the upper limit of the said content rate of a structural unit (x3) can also be selected from either 75 mass%, 70 mass%, 65 mass%, 60 mass%, etc., for example.

The acrylic polymer (X) may contain other structural units other than the structural units (x1) to (x3).
Monomers from which other structural units are derived include monomers such as 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.

  In addition, the glass transition temperature (Tg) of the acrylic polymer (X) adjusts the tackiness of the pressure-sensitive adhesive layer to an appropriate range and further improves the adhesion between the formed pressure-sensitive adhesive layer and the protective film-forming film. From the viewpoint that it can be made, it is preferably −66 to 10 ° C., more preferably −64 to 10 ° C., and further preferably −62 to 10 ° C. And the lower limit of the glass transition temperature (Tg) of acrylic polymer (X) can also be selected from -50 degreeC, -40 degreeC, -30 degreeC, etc., for example. If the said lower limit is -50 degreeC or more, pick-up suitability can also be kept favorable, improving the adhesiveness of an adhesive layer and the film for protective film formation more.

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 thickeners, wetting agents, leveling agents, and antifoaming agents 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.
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 group that reacts with the functional group of the acrylic polymer (X) and contains 1 to 5 polymerizable groups containing energy beam polymerizable carbon-carbon double bonds per molecule. It is preferable that it is a compound which has.
Examples of the group that reacts with the functional group of the acrylic polymer (X) include an isocyanate group, a carboxy group, and an epoxy group, and an isocyanate group is preferable.
Examples of the polymerizable group containing an energy beam polymerizable carbon-carbon double bond include a (meth) acryloyl group and a vinyl group, and 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, the viewpoint that it has a preferable isocyanate group as a group that reacts with the functional group of the acrylic polymer (X), and the distance between the acrylic polymer (X) and the polymerizable group is appropriate. Therefore, (meth) acryloyloxyethyl isocyanate is preferable.

  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, ethyl acetate or the like can be used. Examples thereof include a method in which a reaction such as dibutyltin laurate is performed in an organic solution at a temperature of about room temperature and a 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 is more preferably 30 to 95 equivalents, still more preferably 40 to 90 equivalents, and particularly preferably 55 to 85 equivalents.

  The compounding amount of the polymerizable compound (Y) with respect to 100 parts by mass of the acrylic polymer (X) is preferably from the viewpoint of further improving the adhesion between the pressure-sensitive adhesive layer and the protective film-forming film (protective film). 1-40 mass parts, More preferably, it is 5-37 mass parts, More preferably, it is 10-35 mass parts, Most preferably, it is 14-33 mass parts. And the upper limit of the said compounding quantity of polymeric compound (Y) can also be selected from either 30 mass parts, 25 mass parts, etc., for example. If the said upper limit is 30 mass parts or less, the laser marking aptitude of the protective film formed using a composite sheet will improve.

In the present invention, the value of α calculated from the following formula (2) is 28 or less with respect to the relationship between the blending amounts of the acrylic polymer (X) and the polymerizable compound (Y).
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 an equivalent amount of the polymerizable compound (Y) with respect 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 28 or less, preferably 25 or less, more preferably 23 or less, further preferably 20 or less, particularly preferably 18 or less, particularly preferably 17 or less, and most preferably 16 or less. Further, from the viewpoint of improving pick-up suitability, the value of α is preferably 1 or more, more preferably 5 or more. In addition, as described above, by using an energy ray-curable acrylic copolymer containing a predetermined amount of the structural unit derived from methyl methacrylate (x1), even if the value of α is low, the pickup suitability is further improved. Become.

[Photopolymerization initiator]
The pressure-sensitive adhesive composition used in the present invention preferably further contains a photopolymerization initiator. When the pressure-sensitive adhesive composition contains a photopolymerization initiator, when the pressure-sensitive adhesive layer is irradiated with energy rays to cure the pressure-sensitive adhesive layer, the polymerization curing time is shortened and the amount of light irradiation is reduced. In addition, the curing of the pressure-sensitive adhesive layer can proceed to form a cured 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 amount of the photopolymerization initiator in the pressure-sensitive adhesive composition is such that the energy ray curable acrylic copolymer 100 can be used from the viewpoint of sufficiently proceeding the curing reaction, improving pickup suitability, and suppressing the formation of residues. Preferably it is 0.1-10 mass parts with respect to a mass part, 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. When the pressure-sensitive adhesive composition contains a cross-linking agent, the cross-linking reaction with the functional group of the acrylic polymer (X) forms a network structure, and the cohesive force of the formed pressure-sensitive adhesive layer is improved, and the adhesive strength Can be controlled.
Examples of the crosslinking agent include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, organic polyvalent imine compounds, and the like.

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

  Specific organic polyvalent isocyanate compounds include, for example, tolylene diisocyanate compounds such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate Diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane -2,4'-diisocyanate; lysine isocyanate; and these polyhydric alcohol adducts (polyhydric alcohol adducts).

  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 compounding amount of the crosslinking agent in the pressure-sensitive adhesive composition is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0 with respect to 100 parts by mass of the acrylic copolymer. 3 to 5 parts by mass.

[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 the tackifying resin include rosin resin, hydrogenated rosin resin, terpene resin, hydrogenated terpene resin, C5 petroleum resin obtained by copolymerizing C5 fraction, and hydrogen of C5 petroleum resin. And C9 petroleum resin obtained by copolymerization of C9 fraction, hydrogenated petroleum resin of C9 petroleum resin, 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 on a base material by a well-known method, forming a coating film, drying the said coating film, and forming an adhesive layer.
Moreover, 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 this case, when the pressure-sensitive adhesive sheet is used, the release sheet is removed, and a protective film-forming film is laminated on the exposed pressure-sensitive 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 15-70 mass%, More preferably, it is 20-65 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, the pressure-sensitive adhesive layer may be cured by irradiating energy rays such as ultraviolet rays from the release sheet side or the substrate side.
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, these components may be referred to as “component (A) to component (F)” corresponding to the reference numerals).
Hereinafter, the components (A) to (F) contained in the protective film-forming film will be described.

[(A) Polymer component]
“(A) 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, Most 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. Especially 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. More preferably, it is 150,000 to 1,200,000, particularly 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 particularly 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 independently and may be used in combination of 2 or more type.
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, hexyl (meth) acrylate, and heptyl (meth). Acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, Dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, tetradecyl (meth) acrylate (myristyl (meth) acrylate), pentadecyl (meth) acrylate Relate, hexadecyl (meth) acrylate (palmityl (meth) acrylate), heptadecyl (meth) acrylate, octadecyl (meth) acrylate (stearyl (meth) acrylate), isooctadecyl (meth) acrylate (isostearyl (meth) acrylate), etc. Can be mentioned.
These alkyl (meth) acrylates may be used alone or in combination of two or more.

Among these, 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, the alkyl (meth) acrylate constituting the structural unit (a1) is carbon. An alkyl (meth) acrylate having an alkyl group of 4 or more is preferred, an alkyl (meth) acrylate having an alkyl group having 4 to 6 carbon atoms is more preferred, and butyl (meth) acrylate is still more preferred.
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 the 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 comprises a structural unit (a1) has a C1-C3 alkyl group. Alkyl (meth) acrylate is preferred, and methyl (meth) acrylate is more preferred.
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 the 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, and still more preferably 55 to 90% by mass, based on all the structural units of the (A1) acrylic polymer. Especially preferably, it is 60-80 mass%.

(Structural unit (a2))
Examples of the functional group-containing monomer constituting the structural unit (a2) include the same functional group-containing monomers as those constituting the structural unit (x2). For example, a hydroxy group-containing monomer, a carboxy group-containing monomer, an epoxy Examples thereof include a group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer, a monomer having a nitrogen atom-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 group-containing monomer include those exemplified as the hydroxy group-containing monomer constituting the structural unit (x2), and 2-hydroxyethyl (meth) acrylate is preferable.

As a carboxy group containing monomer, what was illustrated as a carboxy group containing monomer which comprises a structural unit (x2) is mentioned.
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) curable component mentioned later, since the carboxy group and the epoxy group in an epoxy-type thermosetting component will react, it originates in a carboxy-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. 10 mass%, More preferably, it is 0-5 mass%, More preferably, it is 0-2 mass%, Most preferably, it is 0 mass%.

  Examples of the epoxy group-containing monomer include those exemplified as the epoxy 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 all the structural units of the (A1) acrylic polymer. Especially 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 polymer)
The protective film-forming film may contain (A2) a non-acrylic polymer as a resin component other than the above-described (A1) acrylic polymer, if necessary.
Examples of (A2) non-acrylic polymers include polyesters, phenoxy resins, polycarbonates, polyethers, polyurethanes, polysiloxanes, rubber polymers, and the like.
(A2) A non-acrylic polymer may be used independently and may be used in combination of 2 or more type.

  (A2) The weight average molecular weight of the non-acrylic polymer 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 polymer may be used alone, but it can be easily separated from the pressure-sensitive adhesive sheet and the protective film-forming film by using in combination with the above-mentioned (A1) acrylic polymer. And generation of voids can be suppressed.
When the (A2) non-acrylic polymer is used in combination with the above-described (A1) acrylic polymer, the mass ratio of (A2) non-acrylic polymer 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 a protective film-forming film to form a hard protective film, and is a compound having a weight average molecular weight of less than 20000.
(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. Epoxy compounds having two or more functional groups in a molecule such as cyclopentadiene type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin, etc. Can be mentioned.
These epoxy compounds (B11) may be used alone or in combination of two or more.

  In the protective film-forming film, the content of the epoxy compound (B11) is preferably 1 to 500 parts by mass, more preferably 3 to 300 parts by mass, and still more preferably 10 to 100 parts by mass of the component (A). 150 parts by mass, particularly preferably 20 to 120 parts by mass.

(Thermosetting agent (B12))
The thermosetting agent (B12) functions as a curing agent for the epoxy compound (B11).
As a thermosetting agent, the compound which has 2 or more of functional groups which can react with an epoxy group in 1 molecule is preferable.
Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and a group in which an acid group has been anhydrideized. Among these, a phenolic hydroxyl group, an amino group, or a group in which an acid group has been anhydrideized is preferable, a phenolic hydroxyl group or an amino group is more preferable, and an amino group is still more preferable.

Examples of the phenol-based thermosetting agent having a phenolic hydroxyl group include polyfunctional phenol resins, biphenols, novolac-type phenol resins, dicyclopentadiene-type phenol resins, zyloc-type phenol resins, and aralkyl phenol resins.
Examples of the amine-based thermosetting agent having an amino group include dicyandiamide (DICY).

  A thermosetting agent (B12) may be used independently and may be used in combination of 2 or more type.

  In the protective film-forming film, the content of the thermosetting agent (B12) is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, with respect to 100 parts by mass of the epoxy compound (B11). is there.

(Curing accelerator (B13))
The protective film-forming film may contain a curing accelerator (B13) in order to adjust the rate of thermal curing. 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.

  In the protective film-forming film, the content of the curing accelerator (B13) is selected from the viewpoints of improving the adhesion of the protective film formed from the protective film-forming film, and the chip with the protective film manufactured using the composite sheet From the viewpoint of improving the reliability of the epoxy compound (B11) and the thermosetting agent (B12), the total amount of 100 parts by mass is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 6 parts by mass. Part, more preferably 0.3 to 4 parts by weight.

(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 100-30000, More preferably, it is 300-10000.

  In the protective film-forming film, 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 the photopolymerization initiator (B22) together with the energy ray-reactive compound (B21) described above, 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.
As a photoinitiator (B22), the same thing as the photoinitiator in the said adhesive composition is mentioned.
In the protective film-forming film, the content of the photopolymerization initiator (B22) is based on 100 parts by mass of the energy ray-reactive compound (B21) from the viewpoint of sufficiently promoting the curing reaction and suppressing the formation of a residue. The amount is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass.

(B) Content of a sclerosing | hardenable component becomes like this. Preferably it is 5-50 mass% with respect to the whole quantity (100 mass%) of the film for protective film formation, More preferably, it is 8-40 mass%, More preferably, it is 10-30. % By mass, particularly preferably 12 to 25% by mass.
In addition, content of (B) curable component is the thermosetting component (B1) containing the above-mentioned epoxy compound (B11), thermosetting agent (B12), and hardening accelerator (B13), and energy beam reaction. It is the total content of the energy ray-curable component (B2) including the functional compound (B21) and the photopolymerization initiator (B22).

[(C) Colorant]
The protective film-forming film preferably further contains (C) a colorant.
The protective film-forming film contains the colorant (C), so that when a semiconductor chip having a protective film formed from the protective film-forming film is incorporated in a device, it shields infrared rays generated from surrounding devices. It is possible to prevent malfunction of the semiconductor chip.

(C) As the colorant, organic or inorganic pigments and dyes can be used.
Examples of the dye include acid dyes, reactive dyes, direct dyes, disperse dyes, and cationic dyes.
The pigment is not particularly limited and can be appropriately selected from known pigments.
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, these (C) coloring agents may be used independently and may be used in combination of 2 or more type.

  The content of (C) the colorant is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, and still more preferably based on the total amount (100% by mass) of the protective film-forming film. It is 1.0-15 mass%, Most preferably, it is 1.2-5 mass%.

[(D) Coupling agent]
The protective film-forming film preferably further includes (D) a coupling agent.
When the protective film-forming film contains (D) a coupling agent, the polymer component in the protective film-forming film is bonded to the surface of the semiconductor chip or the filler, which is the adherend, so that adhesion or aggregation Can be improved. 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 100-15000, more preferably 150-10000, still more preferably 200-5000, particularly preferably 250-3000, most preferably 350-2000.

  (D) The content of the coupling agent is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, and still more preferably based on the total amount (100% by mass) of the protective film-forming film. Is 0.10 to 4% by mass, particularly preferably 0.15 to 2% by mass.

[(E) Inorganic filler]
The protective film-forming film preferably further contains (E) an inorganic filler.
When the protective film-forming film contains the inorganic filler (E), 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 it is cured to the semiconductor chip. The reliability of the semiconductor device can be improved by optimizing the thermal expansion coefficient of the subsequent protective film. 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, as the (E) inorganic filler, 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.

  (E) The content of the inorganic filler is preferably 25 to 80% by mass, more preferably 30 to 70% by mass, and still more preferably 40 to 65% with respect to the total amount (100% by mass) of the protective film-forming film. % By mass, particularly preferably 45 to 60% by mass.

[(F) General-purpose additive]
In addition to the above, the protective film-forming film may contain various (F) general-purpose additives as required.
(F) General-purpose additives include crosslinking agents, leveling agents, plasticizers, antistatic agents, antioxidants, ion scavengers, gettering agents, chain transfer agents, and the like.

<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 coating solution is formed on the release sheet by a known coating method to form a coating film. Then, this coating film can be dried, and the film for protective film formation can be formed and manufactured on a peeling sheet.

Examples of the organic solvent to be used include toluene, ethyl acetate, methyl ethyl ketone and the like.
The solid content concentration of the raw material composition solution 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 layers.
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, The total thickness is preferably in the above 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.

Further, the composite sheet of the present invention can be used as a sheet for fixing a workpiece such as a semiconductor wafer (ie, a dicing sheet) when blade dicing, and it is not necessary to separately dice the dicing sheet and dice the semiconductor device. The manufacturing process can be simplified.
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.

  When the protective film-forming composite sheet of the present invention is used, after the protective film-forming film of the protective film-forming composite sheet is attached to a workpiece, the protective film-forming film is removed from the protective film-forming composite sheet. The protective film formed by curing the protective film-forming film under the conditions of 130 ° C. and 2 hours without peeling off has, for example, a gloss value of 30 or more. In the present invention, the protective film having a higher gloss value can be formed. For example, the gloss value of the protective film can be preferably 40 or more, more preferably 44 or more.

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

About the chip | tip with a protective film of this invention, the gross value of the protective film measured from the opposite side to the chip | tip side of the chip | tip with a protective film is 30 or more, for example, Preferably it is 40 or more, More preferably, it is 44 or more. Yes, and preferably 90 or less. When the gloss value is 40 or more, a chip with a protective film that is particularly 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 semiconductor device can be manufactured by mounting the chip with a protective film on a substrate or the like by a face-down method. Further, the semiconductor device can be manufactured by adhering the chip with the protective film on another member (on the 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, regardless of the order of process (2) and (3), it is protective film in order of process (1), (2), (3), (4). A chip with a protective film may be manufactured, or a chip with a protective film may be manufactured in the order of steps (1), (3), (2), and (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, for example, a compound semiconductor wafer such as gallium / arsenic. In addition, the semiconductor wafer may have a circuit formed on the front surface thereof and the back surface appropriately ground or the like to have 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 with the film for protective film formation obtained through the process (1) may be sufficient as the workpiece | work which is the target object which carries out a dicing at this process, and after a process (1), a process (3) is preceded. 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 for example, as described above, a protective film having a gloss value of 40 or more can be formed.

The protective film-forming film can be cured by heating, irradiation with energy rays, or both depending on the type of the curable component contained therein. However, it is preferable to cure at least by heating 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.
When curing is performed by heating, the curing temperature is preferably 100 to 150 ° C., and the curing time is preferably 1 to 3 hours.
Moreover, the curing 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 separated 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. On the other hand, in the method for producing a chip with a protective film of the present invention, by forming a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition containing a specific energy ray-curable acrylic copolymer, the pickup suitability becomes good, The productivity of the chip with protective film can also be improved.

Since the chip with a protective film obtained by the production method of the present invention can increase the gloss value of the protective film, it can be a chip with a protective film excellent in laser marking suitability.
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 the chip | tip with a protective film is 30 or more, for example, Preferably it is 40 or more, more Preferably it is 44 or more.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
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 described 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” (all 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 solid content concentration of 61% by mass is protected. A solution of the raw material composition of the film 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%), weight average molecular weight: 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 (manufactured by DIC Corporation, 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) Coupling agent>
Silane coupling agent (Nihon Unicar Co., Ltd., trade name “A-1110”): 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 A solution of the prepared raw material composition 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 to 5, Comparative Example 1]
(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>
Addition of methacryloyloxyethyl acrylate to the acrylic polymer derived from the raw material monomers of the types and proportions shown in Table 1 in the blending amounts shown in Table 1, ethyl acetate is added to form an ethyl acetate solution, and dibutyltin laurate is used as a catalyst. Acrylic copolymers A1 to A6 synthesized by reaction at 25 ° C. and 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 acrylic copolymers A1 to A6 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.

(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, is dried at 100 ° C. for 1 minute, forms an adhesive layer on the release sheet, and has a thickness of 100 μm as a base material on the adhesive layer. (Mitsubishi Resin Co., Ltd., brand name "CT265") was laminated.
Then, from the release sheet side, an ultraviolet irradiation device (product name “RAD-20, manufactured by Lintec Corporation”).
00m / 12 "was irradiated with ultraviolet rays (illuminance 140 mW / cm ² , light amount 510 mJ / cm ² ) to cure the entire surface of the pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer including a cured region was produced.

(3) Preparation of protective sheet-forming composite sheet The release sheet of the produced pressure-sensitive adhesive sheet was removed to expose the pressure-sensitive adhesive layer. Furthermore, in the protective film-forming film produced in Production Example 1, one of the sandwiched two release sheets was removed to expose the protective film-forming film. Then, after directly laminating the exposed protective film-forming film on the cured area of the adhesive layer exposed on the adhesive sheet, the remaining release sheet is also removed to further display the protective film-forming film. I made it come out.
On the other hand, in a double-sided pressure-sensitive adhesive tape having a release sheet on both sides of the pressure-sensitive adhesive layer (product name “Adwill G-01DF”, manufactured by Lintec Corporation) One release sheet was removed, and the adhesive layer was exposed. And this adhesive layer was laminated | stacked on the surface of said exposed film for protective film formation, and the jig | tool adhesion layer stuck on a ring frame part was formed.
Furthermore, in accordance with the outer diameter (diameter 270 mm) of the margin for the ring frame, the laminated body obtained above is die-cut in a circular shape so as to be concentric with the circular part extracted from the double-sided adhesive tape, A composite sheet for forming a protective film having the configuration shown in FIG.

  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, polished surface of silicon wafer subjected to # 2000 polishing, and protective film of protective film forming composite sheet prepared in Examples and Comparative Examples The film for formation was stuck while heating to 70 ° C. using an adhesive sheet sticking device (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 a size.
Then, it was observed visually whether there was infiltration of cutting water between a protective film and an adhesive layer from a cutting part.
Table 2 shows the number of wafers in which the above operation was performed on 30 wafers and the above cutting water did not enter.

(2) Gloss value Adhesive sheet pasting the polished surface of # 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 taken as the gloss value of the protective film.

(3) Laser marking suitability A thickness of 200 μm, a diameter of 8 inches, a polished surface of a silicon wafer subjected to # 2000 polishing, and a protective film forming film of a composite sheet for forming a protective film prepared in Examples and Comparative Examples, Using an adhesive sheet sticking device (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 the chip | tip with a protective film using the composite sheet for protective film formation of Examples 1-5, the penetration | invasion of cutting water was not seen between the protective film and the adhesive layer at the time of dicing.
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 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 protective film manufactured using the composite sheet for forming a protective film of Examples 1 to 3 is high, the chip with protective film is It is considered that the laser marking suitability is also 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 Example 1, intrusion of cutting water was observed between the protective film and the adhesive layer.

  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 ... Composite sheet for forming a protective film (composite sheet)
DESCRIPTION OF SYMBOLS 10,10a ... Adhesive sheet 11 ... Base material 12 ... Adhesive layer 12a ... Curing area 13 ... Energy ray shielding layer 20 ... Film for protective film formation 31 ... Jig Adhesive layer 41 ... Jig adhesive adhesive layer

Claims (12)

A protective film-forming composite sheet comprising a pressure-sensitive adhesive sheet having a substrate and a pressure-sensitive adhesive layer, and a protective film-forming film laminated directly on the pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer is a layer formed from a pressure-sensitive adhesive composition containing an energy ray curable acrylic copolymer,
The above-mentioned energy ray-curable acrylic copolymer is prepared by adding a polymerizable compound (Y) having an energy ray-polymerizable group to an acrylic polymer (X) containing 35% by mass or less of a functional group-containing monomer-derived structural unit (x2). It is an acrylic copolymer into which an energy beam polymerizable group is introduced, obtained by reaction,
The composite sheet for protective film formation whose value of (alpha) computed from following formula (2) of the said energy-beam curable acrylic copolymer is 28 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 an equivalent amount of the polymerizable compound (Y) with respect 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 composite sheet for forming a protective film according to claim 1, wherein the acrylic polymer (X) contains 10 mass% or more of a structural unit (x1) derived from methyl methacrylate.   3. The composite sheet for forming a protective film according to claim 1, wherein at least a part of the pressure-sensitive adhesive layer forms a cured region, and the protective film-forming film is directly laminated on the cured region. .   The composite sheet for protective film formation as described in any one of Claims 1-3 whose said energy-beam polymeric group is a (meth) acryloyl group.   The composite sheet for protective film formation as described in any one of Claims 1-4 in which the said film for protective film formation contains (A) polymer component and (B) sclerosing | hardenable component.   The composite sheet for forming a protective film according to claim 5, 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 any one of claims 1 to 6, 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 7, wherein the base material is a base material containing polypropylene.   The chip | tip with a protective film which has a protective film formed by hardening | curing the protective film formation film of the composite sheet for protective film formation as described in any one of Claims 1-8 on the back surface of a chip | tip.   The chip | tip with a protective film of Claim 9 whose gloss value of the protective film measured from the opposite side to the chip | tip side with the chip | tip with the said protective film is 40 or more. The manufacturing method of the chip | tip with a protective film which has following process (1)-(4).
Process (1): The process of sticking the composite sheet for protective film formation as described in any one of Claims 1-8 on the back surface of a workpiece | work Process (2): The process of dicing a work process (3): Said protection Step of curing the protective film-forming film without peeling off the adhesive sheet of the film-forming composite sheet Step (4): Picking up the diced workpiece with the protective film obtained through the steps (1) to (3) , Process for obtaining chip with protective film   It is a chip | tip with a protective film obtained by the manufacturing method of Claim 11, Comprising: The gross value of the protective film measured from the opposite side to the chip | tip side of the said chip | tip with a protective film is 40 or more. Chip.

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