TWI662103B - Composite sheet for forming protective film - Google Patents

Abstract

The present invention relates to a composite sheet for forming a protective film, comprising: an adhesive sheet formed by laminating an adhesive layer on one side of a substrate; and a protective film forming film laminated on the adhesive layer side of the adhesive sheet; When a load of 0.1 g / mm is applied to the aforementioned substrate, and the substrate is heated at 130 ° C for 2 hours and cooled to 23 ° C, the expansion ratio of the aforementioned substrate to the MD direction and CD direction before heating are both 95% to 103 %, And the tensile elastic modulus in the MD direction and the CD direction of the substrate at 23 ° C are both 100 MPa to 700 MPa.

Description

Composite sheet for protective film formation

The present invention relates to a composite film for forming a protective film, which is then attached to a workpiece such as a semiconductor wafer and can process (e.g., cut) the workpiece in this state, and can process the workpiece (such as a semiconductor) Wafer) to form a protective film.

In recent years, a semiconductor device has been manufactured using a mounting method called a face-down method. In this method, when a semiconductor wafer having a circuit surface on which electrodes such as bumps are formed is mounted, the circuit surface side of the semiconductor wafer is bonded to a wafer mounting portion such as a lead frame. Therefore, a structure in which the back side of the semiconductor wafer on which the circuit is not formed is formed is formed.

Therefore, in order to protect the semiconductor wafer, a protective film containing a hard organic material is formed more than the back side of the semiconductor wafer. Therefore, Patent Document 1 discloses a sheet for protective film formation and dicing having a thermosetting protective film forming layer capable of forming the protective film. Formed and cut by this protective film Sheet, both the dicing of the semiconductor wafer and the formation of a protective film on the semiconductor wafer can be performed, and a semiconductor wafer with a protective film can be obtained.

When using the protective film to form and cut a sheet, a peripheral portion of the sheet is attached to a ring frame, a protective film forming layer is attached to a semiconductor wafer, and a heating step is performed in this state. , And then proceed to the cooling step. By going through these steps, the protective film forming layer system is thermally hardened to form a protective film.

However, the conventional protective film forming and dicing sheet may cause a problem that when the heating step is performed while supporting the protective film forming and dicing sheet with a ring-shaped frame, the protection may be caused by the weight of the semiconductor wafer. The film-forming and dicing sheet is slack and does not recover even after the cooling step. If the protective film formation and dicing sheet is loosened as described above, a defect may occur when it is stored in the box during transportation, or the vacuum adsorption of the sheet may not be smoothly performed on the adsorption table, which is further outside than the corresponding part of the wafer, and Defects such as wrinkles occur in the sheet, or defects occur because the sheet is already stretched during stretching.

In addition, Patent Document 1 discloses a configuration in which a protective film forming layer is directly laminated on a supporting film as a protective film forming and dicing sheet (FIG. 1). However, if there is no adhesive layer between the supporting film and the protective film forming layer, the following problems will occur: Then, the force is too strong to pick up the wafer, or the adhesion force between the support film and the protective film forming layer is too weak, and the wafer falls off during dicing.

Patent Document 2 discloses a dicing sheet with a protective film forming layer having the same structure as the protective film forming and dicing sheet of Patent Document 1. This Patent Document 2 mentions relaxation during heat curing, but does not consider restoration in the cooling step.

Furthermore, Patent Document 3 discloses a method for manufacturing a semiconductor device using a film for semiconductor back surface as a protective film forming layer and a dicing tape, respectively. In the method of Patent Document 3, the dicing is performed in a state where the film for semiconductor back surface is not hardened, and after the wafer is picked up, the film for semiconductor back surface is thermally cured, so that the problems caused by the relaxation described above are not caused. .

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2006-140348

Patent Document 2: WO2013 / 047674

Patent Document 3: Japanese Patent Laid-Open No. 2012-156377

The present invention has been made in view of the facts described above, and an object thereof is to provide a protective film-forming composite sheet that can effectively suppress slackening of a sheet that has undergone a heating step and a cooling step, and can perform pick-up well.

To achieve the above object, the present invention includes the following aspects.

(1) A composite sheet for forming a protective film is provided, comprising: an adhesive sheet formed by laminating an adhesive layer on one side of a substrate; and a protective film forming film laminated on the adhesive layer side of the adhesive sheet ; When a load of 0.1 g / mm is applied to the substrate and heated at 130 ° C. for 2 hours and cooled to 23 ° C., the expansion ratio of the substrate after the heating relative to the MD direction and the CD direction before the heating are both 95% ~ 103%, and the tensile elastic modulus in the MD direction and the CD direction of the substrate at 23 ° C are 100 MPa to 700 MPa.

Furthermore, in this specification, "sheet" includes the concept of a tape.

In one aspect of the present invention, the composite sheet for forming a protective film includes a substrate, an adhesive layer, and a protective film-forming film, and the substrate, the adhesive layer, and the protective film-forming film are sequentially laminated to the substrate. When a load of 0.1 g / mm is applied and heated at 130 ° C. for 2 hours and cooled to 23 ° C., the aforementioned substrates have an expansion and contraction rate of 95% to 103% relative to the MD direction and CD direction before the heating, In addition, the tensile elastic modulus in the MD direction and the CD direction of the substrate at 23 ° C. are both 100 MPa to 700 MPa.

In another aspect of the present invention, the adhesive sheet is a laminated body formed by layering the adhesive layer on an area of the substrate.

According to the aspect (1), by making the base material have physical properties related to the above-mentioned stretch ratio, it is possible to effectively suppress the slackness of the protective film-forming composite sheet after the heating step and the cooling step. Furthermore, by making the base material have physical properties related to the above-mentioned tensile elastic modulus, the adhesive sheet has moderate flexibility, and can be stretched (if necessary) and picked up after cutting well.

(2) In the aspect (1), the substrate is preferably a polypropylene film.

(3) In the aspect of (1) or (2), the thickness of the aforementioned substrate is preferably 50 μm to 200 μm.

(4) In any one of the aspects (1) to (3), the composite sheet for forming a protective film is preferably provided with an adhesive layer for a jig, and the adhesive layer for the jig is laminated on the protective film. The peripheral edge portion of the film is opposite to the side of the adhesive sheet.

(5) In any one of aspects (1) to (4), it is preferable to include a release sheet laminated on the protective film forming film.

(6) In any one of aspects (1) to (5), the protective film forming film is preferably a layer for forming a protective film on a semiconductor wafer or a semiconductor wafer obtained by dicing the semiconductor wafer.

(7) In any of the aspects (1) to (6), it is preferable that the substrate is heated to 130 ° C at a temperature increase rate of 10 ° C / min, and maintained at the temperature for 2 hours. At the time point, it has a weight reduction rate of 0.01% or more and 2% or less, more preferably 0.9% or less, and still more preferably 0.5% or less.

(8) In any of the aspects (1) to (4), (6), and (7), it is preferable that the composite sheet for forming a protective film forms the composite sheet for forming a protective film at a temperature increase rate of 10 ° C. The time when the temperature is raised to 130 ° C per minute and maintained at this temperature for 2 hours, it has a value of 0.01% or more and 6.0% or less, more preferably 3.0% or less, still more preferably 2.5% or less, and even more preferably 1.2% or less. Weight reduction rate.

(9) In any of the aspects (1) to (8), the melting point of the aforementioned substrate is preferably 130 ° C or higher, more preferably 130 ° C to 170 ° C, and still more preferably 130 ° C to 160 ° C, especially It is preferably 131 ° C to 156 ° C.

According to the composite sheet for forming a protective film according to the present invention, the slackness of the sheet after the heating step and the cooling step is effectively suppressed, and the pick-up can be performed well.

1, 10‧‧‧ composite sheet for protective film formation

2‧‧‧ adhesive sheet

21‧‧‧ substrate

22‧‧‧ Adhesive layer

3‧‧‧ protective film forming film

4‧‧‧ Adhesive layer for jig

5‧‧‧ semiconductor wafer

6‧‧‧ ring frame

7‧‧‧ peeling sheet

FIG. 1 is a cross-sectional view of a composite sheet for forming a protective film according to an embodiment of the present invention.

FIG. 2 is a plan view of a protective film-forming composite sheet in a state of being attached to a workpiece.

Fig. 3 is a cross-sectional view showing an example of use of a protective film-forming composite sheet according to an embodiment of the present invention.

4 is a cross-sectional view of a composite sheet for forming a protective film according to an embodiment of the present invention.

An embodiment of the present invention will be described below.

FIG. 1 is a cross-sectional view of a protective film-forming composite sheet according to an embodiment of the present invention, and FIG. 2 is a plan view of the protective film-forming composite sheet in a state of being attached to a workpiece. As shown in FIG. 1, the protective film-forming composite sheet 1 of this embodiment is configured to include: an adhesive sheet 2 formed of an adhesive layer 22 on an area of a substrate 21; and a protective film-forming film 3 formed of an adhesive layer The adhesive layer 22 side of the sheet 2 and the adhesive layer 4 for the jig are laminated on the peripheral edge portion of the protective film forming film 3 opposite to the adhesive sheet 2 side. It should be noted that the protective film-forming composite sheet 1 according to this embodiment refers to a person who has not yet attached the protective film-forming film 3 to a workpiece.

In this embodiment, as shown in FIGS. 1 and 2, the base material 21 and the adhesive layer 22 of the adhesive sheet 2 and the protective film-forming film 3 are formed in the same size and shape, and are circular in a plan view. It is not limited to this. E.g, The adhesive sheet 2 and the protective film forming film 3 may have different sizes or shapes, or may be a polygon or a shape including a combination of an arc and a straight line in a plan view.

In addition, in this embodiment, as shown in FIGS. 1 and 2, the adhesive layer 4 for a jig is formed in a ring shape, and its outer periphery is the same as the outer periphery of the adhesive sheet 2 and the protective film-forming film 3 in plan view. Location, but the invention is not limited to this. For example, the adhesive layer 4 for a jig may not be ring-shaped and may be broken in the middle, and the outer peripheral edge may be different from the outer peripheral edge of the adhesive sheet 2 or the protective film-forming film 3 in a plan view.

The protective film-forming composite sheet 1 according to the embodiment is used for attaching and holding a workpiece while processing the workpiece, and for forming a protective film on the workpiece or a wafer obtained from the workpiece. In this embodiment, the protective film is formed by thermally curing the protective film forming film 3. As an example, the composite film 1 for forming a protective film according to the embodiment is used for holding a semiconductor wafer during dicing of a semiconductor wafer as a workpiece and forming a protective film on the semiconductor wafer obtained by dicing, but it is not limited to this. this.

Adhesive sheet

The adhesive sheet 2 of the protective film-forming composite sheet 1 of this embodiment includes a base material 21 and an adhesive layer 22 laminated on one surface of the base material 21.

1-1. Substrate

The base material 21 of the protective film-forming composite sheet 1 of this embodiment has the following physical properties: When a load of 0.1 g / mm is applied to the base material 21 and heated at 130 ° C. for 2 hours and cooled to 23 ° C., the heating is relative to the heating. The previous MD (Machine Direction) direction and CD (Cross Direction) direction expansion ratio (hereinafter referred to as "load expansion ratio") are 95% ~ 103%. In this specification, "physical properties" means chemical or physicochemical properties. The method for measuring the load expansion ratio is shown in the test examples described later. Here, the MD direction refers to a production line direction for manufacturing the substrate 21, and the CD direction refers to a direction orthogonal to the MD direction, that is, a width direction for manufacturing the substrate 21.

By providing the base material 21 with the above-mentioned physical properties, it is possible to effectively suppress the slackness of the protective film-forming composite sheet 1 after the heating step and the cooling step. Therefore, the protective film-forming composite sheet 1 of this embodiment is less likely to hinder the steps after the heating and cooling steps.

If the above-mentioned load expansion and contraction ratio is less than 95%, the shrinkage amount of the protective film-forming composite sheet 1 is large, and the workpiece may be damaged due to large internal stress, and the protective film-forming composite sheet 1 may be self-ring The frame and other fixtures may fall off. On the other hand, if the above-mentioned load expansion and contraction ratio exceeds 103%, the slack of the protective film-forming composite sheet 1 is large, and there is a great concern that the hindrance caused by the slack occurs in each step. From the above viewpoint, the above-mentioned load expansion ratio is preferably 96% to 101%, and particularly preferably 97% to 100%.

Here, when no load is applied to the substrate 21 and it is heated at 130 ° C. for 2 hours and cooled to 23 ° C., the expansion ratio after heating with respect to the MD direction and the CD direction before heating (hereinafter referred to as “no load expansion ratio”). ) Is preferably 93% to 100%, more preferably 95% to 100%, still more preferably 97% to 100%, and even more preferably 98% to 100%. The method for measuring the no-load expansion and contraction rate is shown in the test examples described later.

When the workpiece (semiconductor wafer) is extremely thin in the actual manufacturing process, if the no-load expansion ratio is more than 93%, the shrinkage of the protective film-forming composite sheet 1 is small, which can suppress the workpiece from generating large internal stress and causing damage to the workpiece. Happening. In addition, the composite sheet 1 for forming a protective film can be prevented from falling off from a jig such as a ring frame. On the other hand, if the no-load expansion ratio is 100% or less, the slack of the protective film-forming composite sheet 1 becomes small, and the possibility of occurrence of obstacles due to slack in each step can be reduced.

In addition, the tensile elastic modulus (Young's modulus) in the MD direction and the CD direction of the base material 21 of the protective film-forming composite sheet 1 of this embodiment are both 100 MPa to 700 MPa. The measuring method of this tensile elasticity modulus is as shown in the test example mentioned later.

By making the base material 21 have the above-mentioned physical properties, the adhesive sheet 2 has moderate flexibility, and can be stretched (if necessary) and picked up after cutting well. Furthermore, in the general picking step, the adhesive sheet 2 holding the diced wafer is pressed against the jack pin, but by making the adhesive sheet 2 soft The adhesive sheet 2 pressed by the jacking pin pushes the wafer up, thereby the wafer is easily peeled off from the adhesive sheet 2 and therefore the pick-up property is good. The pickup force (the measurement method is shown in a test example described later) is preferably 5N or less, particularly preferably 4N or less, and even more preferably 3N or less.

When the above-mentioned tensile elastic modulus exceeds 700 MPa, the flexibility of the adhesive sheet 2 decreases, and the above-mentioned excellent effects cannot be obtained. On the other hand, if the above-mentioned tensile elastic modulus is less than 100 MPa, the adhesive sheet 2 becomes too soft and cannot be cut well. From the viewpoint described above, the tensile elastic modulus is preferably 120 MPa to 600 MPa, and particularly preferably 150 MPa to 500 MPa.

The substrate 21 preferably has a temperature of 10 ° C./minute to 130 ° C. at a temperature rising rate of 10 ° C./minute, and is held at the temperature for 2 hours, and has a content of 0.01% or more and 2% or less. A weight reduction rate of 0.9%, and more preferably 0.5% or less (the measurement method is shown in the test example described later). That is, the aforementioned weight reduction rate of the base material monomer constituting the base material 21 is preferably 0.01% or more and 2% or less, more preferably 0.01% or more and less than 0.9%, and still more preferably 0.01% or more and 0.5% or less. . By keeping the aforementioned weight reduction rate of the base material monomer constituting the base material 21 within the above range, the base material 21 is not easily deformed when heated, and the base material 21 has the use of a composite sheet for forming a protective film suitable for the embodiment of the present invention. The purpose is excellent heat resistance. In addition, when the aforementioned weight reduction rate of the base material monomer constituting the base material 21 is within the above range, when the composite sheet for forming a protective film according to the embodiment of the present invention is heated, it almost becomes impossible. No gas is generated from the substrate 21, and the deterioration of the protective sheet-forming composite sheet can be suppressed.

The melting point of the substrate 21 is preferably 130 ° C or higher, more preferably 130 ° C to 170 ° C, still more preferably 130 ° C to 160 ° C, and more specifically, 131 ° C to 156 ° C. When the melting point of the base material 21 is within the above range, it is easy to satisfy the aforementioned load expansion ratio and tensile elastic modulus.

In the present specification, "thickness" refers to a cut surface obtained by arbitrarily cutting in the thickness direction of an object, and a thickness is measured at five arbitrary positions using a contact thickness meter, and the value is an average value.

The thickness of the substrate 21 is preferably 50 μm to 200 μm, more preferably 50 μm to 120 μm, and still more preferably 60 μm to 100 μm. When the thickness is less than 50 μm, the load expansion ratio of the substrate 21 tends to increase. On the other hand, if the thickness exceeds 200 μm, the picking property may be reduced.

The material constituting the base material 21 may be any material as long as it has the physical properties described above, and may be appropriately selected from, for example, resin films shown below.

Specific examples of the resin film include a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, and a high-density polyethylene , HDPE) film, such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene Film, polyolefin film such as ethylene / norbornene copolymer film, norbornene resin film; ethylene / vinyl acetate copolymer film, ethylene (/ (meth) acrylic copolymer film, ethylene (/ (methyl) Vinyl copolymer films such as acrylic copolymer films; Polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; Polyethylene films such as polyethylene terephthalate films and polybutylene terephthalate films Polyester film; Polyurethane film; Polyimide film; Polystyrene film; Polycarbonate film; Fluororesin film, etc. In addition, these crosslinked films and ionic polymer films can also be used. The above-mentioned substrate 21 may be a film formed of one of these films, or may be a laminated film in which two or more of these films are combined. Furthermore, in this specification, "(Meth) acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms.

Among the above, a polypropylene film is preferred. The polypropylene film has moderate heat resistance and flexibility according to its type, and easily meets the aforementioned load expansion and contraction modulus and tensile elastic modulus.

In order to improve the adhesiveness with the adhesive layer 22 laminated on the surface of the resin film, the resin film may be subjected to a surface treatment using an oxidation method, a bumping method, or the like, or a primer treatment, if necessary, on one or both sides. Examples of the oxidation method include a corona discharge treatment, a plasma discharge treatment, a chromium oxidation treatment (wet type), a flame treatment, a hot air treatment, ozone, and an ultraviolet irradiation treatment. Examples of the unevenness method include: : Sand blasting, spraying, etc.

The substrate 21 may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler in the resin film.

1-2. Adhesive layer

The adhesive sheet 2 of the protective film-forming composite sheet 1 of this embodiment is provided with an adhesive layer 22 on one surface of the substrate 21. Since the adhesive layer 22 is present, by controlling the adhesive force of the adhesive layer 22, the protective film-forming film 3 can be firmly fixed during dicing, and moderate peeling can be performed to the extent that the wafer obtained by dicing can be easily picked up. Sex. If the non-adhesive layer 22 is used, the following problems occur: the adhesion between the substrate 21 and the protective film-forming film 3 is too strong to pick up the wafer, or the adhesion between the substrate 21 and the protective film-forming film 3 is too weak. , And the wafer comes off during cutting.

The adhesive layer 22 may be formed of a single layer, or may include multiple layers of two or more layers. In the case of multiple layers, the same material (adhesive) or different materials (adhesives) may be included.

The adhesive constituting the adhesive layer 22 may be either a non-hardening adhesive or a hardening adhesive. The hardening adhesive may be in a state before curing or a state after curing. When the adhesive layer 22 includes multiple layers, a non-hardening adhesive and a hardening adhesive may be combined. Examples of the non-hardening adhesive include an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, and a polyvinyl ether adhesive. Among these, an acrylic adhesive is preferable. Examples of the curable adhesive include energy ray curable adhesives and thermosetting adhesives. Among them, energy ray curable adhesives are preferred, and acrylic energy ray curable adhesives are particularly preferred.

When the adhesive layer 22 is composed of an energy ray-curable adhesive, the energy ray-curable adhesive may be uncured or cured when the protective film-forming composite sheet 1 is attached to the adherend. .

As the energy rays, ultraviolet rays, electron beams, and the like are generally used. The irradiation amount of the energy ray varies according to the type of the energy ray. For example, in the case of ultraviolet rays, it is preferably 50 mJ / cm ² to 1000 mJ / cm ² in terms of light amount, particularly preferably 100 mJ / cm ² to 500 mJ / cm ² . In the case of the electron beam, it is preferably about 10 krad to 1000 krad.

The energy ray-curable adhesive constituting the adhesive layer 22 can include a polymer having energy ray-hardenability as a main component, and a polymer having no energy ray-hardenability and a polyfunctional monomer having energy ray-hardenability and A mixture of oligomers is used as the main component.

Hereinafter, a case where the energy ray curable adhesive contains a polymer having energy ray curability as a main component will be described.

In addition, the "main component" here means 60 mass% or more with respect to the total mass of an energy ray hardening adhesive.

The energy ray-curable polymer is preferably a (meth) acrylate (co) polymer (A) (hereinafter referred to as a methacrylic acid (co) polymer) having a functional group (that is, an energy ray-curable group) having energy ray-curable properties introduced into its side chain "Energy ray hardening polymer (A)"). The energy ray-curable polymer (A) is preferably an unsaturated group containing a (meth) acrylic copolymer (a1) having a functional unit-containing monomer unit and a substituent having a bond with the functional group. Obtained by reacting a base compound (a2).

The acrylic copolymer (a1) includes at least a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth) acrylate monomer or a derivative thereof.

The functional group-containing monomer forming a structural unit derived from the functional group-containing monomer preferably has a polymerizable double bond and a hydroxyl group, an amine group, a substituted amine group, an epoxy group, and a carboxyl group in the molecule. Isofunctional monomers.

More specific examples of the functional group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, ( 4-hydroxybutyl meth) acrylate, glycidyl (meth) acrylate, acrylic acid, etc. can be used individually or in combination of 2 or more types.

As the (meth) acrylate monomer, an alkyl (meth) acrylate having 1 to 20 carbon atoms and an alkyl having 3 to 11 carbon atoms can be used. Cycloalkyl (meth) acrylate, benzyl (meth) acrylate. Among these, particularly preferred are alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid. Propyl ester, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like.

The acrylic copolymer (a1) contains the above-mentioned functional group at a ratio of usually 3% to 100% by mass, preferably 5% to 40% by mass, with respect to the total mass of the acrylic copolymer (a1). A structural unit derived from a monomer based on a base, and contains a structure derived from a (meth) acrylate monomer or a derivative thereof in a ratio of usually 0% to 97% by mass, preferably 60% to 95% by mass. unit.

That is, the acrylic copolymer (a1) preferably contains a structural unit derived from the functional group-containing monomer at a ratio of 3% by mass to 100% by mass relative to the total mass of the acrylic copolymer (a1), and The structural unit derived from the (meth) acrylate monomer or a derivative thereof is usually contained in a ratio of 0% to 97% by mass; more preferably, the functional group is contained in a ratio of 5% to 40% by mass. The structural unit derived from a monomer includes a structural unit derived from a (meth) acrylate monomer or a derivative thereof at a ratio of usually 60% to 95% by mass.

In addition, the total mass of the structural unit derived from the functional group-containing monomer and the structural unit derived from the (meth) acrylate monomer or a derivative thereof does not exceed 100% by mass.

The acrylic copolymer (a1) is obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof by a common method, except for these monomers. Dimethacrylamide, vinyl formate, vinyl acetate, styrene, etc. are also copolymerized.

By making the acrylic copolymer (a1) having the above-mentioned functional unit-containing monomer unit (i.e., a structural unit derived from the functional group-containing monomer) and the unsaturated group containing a substituent that will be bonded to the functional group unsaturated The base compound (a2) is reacted to obtain an energy ray-curable polymer (A).

The substituent contained in the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of the functional group of the functional group-containing monomer unit in the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amine group, or a substituted amine group, as the substituent, an isocyanate group or an epoxy group is preferred, and when the functional group is an epoxy group, the substituent is preferably an amine group. , A carboxyl group, or an aziridinyl group, and when the functional group is a carboxyl group, the substituent is preferably an epoxy group.

In addition, the unsaturated group-containing compound (a2) contains one to five, preferably one to two, energy-polymerizable carbon-carbon double bonds per molecule. Specific examples of such an unsaturated group-containing compound (a2) include, for example, 2-methacryloxyethyl isocyanate and m-isopropenyl-α, α-dimethylbenzyl isocyanate. Ester, methacryl isocyanate, allyl isocyanate, 1,1- (bispropenyloxymethyl) ethyl isocyanate; by diisocyanate Acrylic fluorenyl monoisocyanate compound obtained by reacting an ester compound or a polyisocyanate compound with hydroxyethyl (meth) acrylate; by making a diisocyanate compound or a polyisocyanate compound, a polyol compound, and a (meth) acrylic hydroxyl group Acrylic fluorenyl monoisocyanate compound obtained by reaction of ethyl ester; glycidyl (meth) acrylate; 2- (1-aziridinyl) ethyl (meth) acrylic acid, (meth) acrylic acid; or 2- Alkenyl oxazoline compounds such as 2-Vinyl-2-oxazolin and 2-isopropenyl-2-oxazoline.

Among the above, 2-methacryloxyethyl isocyanate is preferred.

The unsaturated group-containing compound (a2) is a ratio of usually 10 equivalents to 100 equivalents, preferably 20 equivalents to 95 equivalents per 100 equivalents of the functional group-containing monomer of the acrylic copolymer (a1). use.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the temperature, pressure, solvent, time, presence or absence of the catalyst, and catalyst can be appropriately selected according to the combination of the functional group and the substituent. Of kind. Thereby, the functional group existing in the acrylic copolymer (a1) reacts with the substituent in the unsaturated group-containing compound (a2) to introduce the unsaturated group into the side chain in the acrylic copolymer (a1), and An energy ray-curable polymer (A) was obtained.

The weight-average molecular weight of the energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 to 1.5 million, and even more preferably 200,000 to 1 million. In addition, the weight average molecular weight (Mw) in this specification is a polystyrene conversion value measured by the gel permeation chromatography method (GPC method).

That is, when the energy-ray-curable adhesive is mainly composed of a polymer having energy-ray-curable properties, the energy-ray-curable adhesive may further contain an energy-ray-curable monomer and / or oligomer (B).

As the energy ray-curable monomer and / or oligomer (B), for example, an ester of a polyol and (meth) acrylic acid can be used.

Examples of the energy ray-curable monomer and / or oligomer (B) include monofunctional acrylates such as cyclohexyl (meth) acrylate and isofluorenyl (meth) acrylate, and trihydroxy Methylpropane tri (meth) acrylate, neopentaerythritol tri (meth) acrylate, neopentaerythritol tetra (meth) acrylate, dinepentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dimethylol tricyclodecane di ( Polyfunctional acrylates such as meth) acrylates, polyester oligo (meth) acrylates, polyurethane oligo (meth) acrylates, and the like.

Among the above, preferred are polyfunctional acrylates and polyurethane oligo (meth) acrylates.

When blending the energy ray-curable monomer and / or oligomer (B), the content of the energy ray-curable monomer and / or oligomer (B) in the energy ray-curable adhesive is relative to the aforementioned energy. The total mass of the linear hardening adhesive is preferably 5 mass% to 80 mass%, and particularly preferably 20 mass% to 60 mass%.

Here, when ultraviolet rays are used as the energy rays for curing the energy ray-curable resin composition, it is preferable to further add a photopolymerization initiator (C), and by using the photopolymerization initiator (C), Can reduce polymerization hardening time and light exposure.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, and benzoin. Methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azo Diisobutyronitrile, diphenylenedione, bisdiphenylenedione, diethylpyrene, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzene Benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1- [4- (1-propenyl) phenyl] acetone}, 2,2- Dimethoxy-1,2-diphenylethane-1-one and the like. These can be used alone or in combination of two or more.

When the energy ray-curable copolymer (A) (when blending an energy ray-curable monomer and / or oligomer (B), the energy ray-curable copolymer (A) and the energy ray-curable monomer are blended. And / or the total amount of oligomer (B) is set as When 100 parts by mass) is used as 100 parts by mass, the photopolymerization initiator (C) is preferably used in an amount in the range of 0.1 to 10 parts by mass, especially 0.5 to 6 parts by mass.

In the energy ray-curable adhesive, in addition to the above-mentioned components, other appropriate components may be blended. Examples of the other components include a polymer component and an oligomer component (D) which do not have energy ray curability.

Examples of the polymer component or oligomer component (D) having no energy ray curability include polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, and the like, and weight average is preferred. Polymers or oligomers with a molecular weight (Mw) of 3,000 to 2.5 million.

In addition, the energy ray-curable adhesive may form a crosslinked structure by a crosslinker (E).

That is, one form of the energy ray-curable adhesive includes the energy ray-curable copolymer (A) and at least one component selected from the group consisting of an energy ray-curable monomer and At least one component (B) in the group formed by the oligomer, the photopolymerization initiator (C), the polymer component or oligomer component (D) having no energy ray hardening property, and the crosslinking agent (E ).

As the crosslinking agent (E), a polyfunctional compound having reactivity with a functional group possessed by the energy ray-curable copolymer (A) and the like can be used. Examples of such a polyfunctional compound include an isocyanate compound Compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxides, metal chelates, metal salts, ammonium salts, reactive phenol resins, and the like.

By using these other components (D) and (E), it is possible to improve the adhesion and peelability before hardening, the strength after hardening, adhesion to other layers, storage stability, and the like. The use amount of these other components is not particularly limited, and may be appropriately determined within a range of 0 to 40 parts by mass based on 100 parts by mass of the energy ray-curable copolymer (A).

Next, a case where the energy ray-curable adhesive contains a mixture of a polymer component having no energy ray curability and a energy-curable polyfunctional monomer and / or oligomer as a main component will be described below.

As the polymer component having no energy ray hardening property, for example, the same component as the aforementioned acrylic copolymer (a1) can be used, or a functional group-containing monomer is not used as a structural unit, and a (meth) acrylate alone can be used. Body or its derivative is an acrylic copolymer or the like having a structural unit. The content of the polymer component having no energy ray curability in the energy ray curable resin composition is preferably 20% to 99.9% by mass, and more preferably 30% relative to the total mass of the energy ray curable resin composition. Mass% to 80% by mass.

As the energy-ray-curable polyfunctional monomer and / or oligomer, the same as the component (B) can be selected. About non-energy ray hardening aggregates The blending ratio of the polymer component and the energy ray-curable polyfunctional monomer and / or oligomer is 100 parts by mass relative to the polymer component having no energy ray-curable polymer component. It is preferably 10 parts by mass to 150 parts by mass, and particularly preferably 25 parts by mass to 100 parts by mass.

In this case, a photopolymerization initiator (C) or a crosslinking agent (E) may be appropriately used in the same manner as described above.

That is, one form of the energy ray hardening adhesive includes a polymer component having no energy ray hardening property, at least one component selected from the group consisting of energy ray hardening polyfunctional monomer and oligomer, and The required one is at least one component selected from the group consisting of a photopolymerization initiator (C) and a crosslinking agent (E).

On the other hand, when an acrylic pressure-sensitive adhesive is used as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 22, the acrylic pressure-sensitive adhesive may be, for example, the same component as the acrylic copolymer (a1) described above, or may not contain a functional group. Acrylic copolymers, etc. whose monomer is a structural unit and whose (meth) acrylate monomer or its derivative is a structural unit. In this case, the acrylic pressure-sensitive adhesive may also have a crosslinked structure by the same crosslinking agent as the aforementioned crosslinking agent (E).

When an acrylic adhesive is used as the adhesive constituting the adhesive layer 22, the adhesive layer 22 may further contain an epoxy resin. When the adhesive layer 22 is composed of an acrylic adhesive, the following cases may occur: The hardening adhesive of the protective film-forming film 3 adjacent to the adhesive layer 22 migrates to the adhesive layer 22 and causes the physical properties of the adhesive layer 22 to change. However, by including an epoxy resin in the adhesive layer 22, it is possible to prevent physical changes caused by the migration of the hardening adhesive.

In the above-mentioned case, the content of the epoxy resin in the adhesive layer 22 is preferably more than 0 parts by mass and 20 parts by mass or less, and particularly preferably 1 to 17 parts by mass relative to 100 parts by mass of the acrylic copolymer. .

The thickness of the adhesive layer 22 in this embodiment is preferably 2 μm to 50 μm, more preferably 2 μm to 40 μm, and even more preferably 3 μm to 30 μm. When the thickness of the adhesive layer 22 is 2 μm or more, excellent adhesive force can be sufficiently exerted, and when the thickness of the adhesive layer 22 is 50 μm or less, processability is improved.

2. Protective film formation film

The protective film forming film 3 may be the same size and shape as a workpiece such as a semiconductor wafer, or may be a size or shape smaller than the workpiece, or may be a size or shape larger than the workpiece.

The protective film-forming film 3 preferably contains an uncured hardening adhesive. In this case, by laminating a workpiece such as a semiconductor wafer on the protective film forming film 3 and curing the protective film forming film 3, the protective film can be firmly adhered to the workpiece, and a protective film having durability can be formed. Formed on wafers, etc. on. The protective film-forming film 3 can be printed well by laser light irradiation at a stage where the curable adhesive is uncured or at a stage after curing.

That is, in one aspect of the present invention, the protective film-forming composite sheet includes a protective film-forming film formed of an uncured hardening material.

The protective film forming film 3 preferably has adhesiveness at room temperature or exhibits adhesiveness by heating. Thereby, when a workpiece such as a semiconductor wafer is superposed on the protective film forming film 3 as described above, the two can be bonded together. Therefore, positioning can be surely performed before the protective film forming film 3 is hardened, and the rationality of the protective film forming composite sheet 1 can be easily made.

The curable adhesive constituting the protective film-forming film 3 having the characteristics described above preferably contains a curable component and an adhesive polymer component. As the curable component, a thermosetting component, an energy ray-curable component, or a mixture thereof may be used. In consideration of the curing method of the protective film-forming film 3 or heat resistance after curing, it is particularly preferable to use the thermosetting component. .

Examples of the thermosetting component include epoxy resin, phenol resin (low molecular weight), melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, and benzo. Benzoxazine resins and the like and mixtures thereof. Among these, epoxy resins, phenol resins, and mixtures thereof can be preferably used. As the thermosetting component, a molecular weight of about 300 to 10,000 is generally used.

The epoxy resin has the property of forming a strong film by three-dimensional network formation after being heated. As such an epoxy resin, various conventionally known epoxy resins can be used, and generally, a molecular weight of about 300 to 2500 is preferable. It is more preferably used in the form of blending an epoxy resin having a molecular weight of 300 to 500 at a normal temperature as a liquid, and an epoxy resin having a molecular weight of 400 to 2500, especially a solid at a temperature of 500 to 2000. The epoxy equivalent of the epoxy resin is preferably 50 g / eq to 5000 g / eq.

Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; butanediol, polyethylene glycol Glycidyl ethers of alcohols such as alcohols and polypropylene glycols; Glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; aniline isocyanurate and other nitrogen-bonding activity Glycidyl or alkyl glycidyl epoxy resins with hydrogen substituted by glycidyl groups; vinyl cyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexane Carboxylic acid ester, 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane, etc. The carbon-carbon double bond undergoes, for example, oxidation, and a so-called alicyclic epoxide into which an epoxy group is introduced. In addition, an epoxy resin having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, or the like can also be used.

Among these, bisphenol-based glycidyl epoxy resin, o-cresol novolac epoxy resin, and phenol novolac epoxy resin can be preferably used. fat. These epoxy resins may be used individually by 1 type, and may be used in combination of 2 or more type.

When an epoxy resin is used, it is preferable to use a heat active type latent epoxy resin hardener in combination as an auxiliary agent. The so-called "thermally active latent epoxy resin hardener" is a type of hardener that does not react with epoxy resin at room temperature and is activated by heating above a certain temperature and reacts with epoxy resin. The activation methods of thermally active latent epoxy resin hardeners are: a method of generating active materials (anions, cations) by a chemical reaction by heating; stably dispersed in epoxy resin near room temperature, and at high temperature with Epoxy resins are dissolved and melted to start the hardening reaction; methods that use molecular sieve-encapsulated hardeners to dissolve at high temperatures to start the hardening reaction; methods that use microcapsules.

Specific examples of the heat-active latent epoxy resin hardener include various onium salts, or diacid dihydrazine compounds, dicyandiamine, amine adduct hardeners, and high-melting-point active hydrogens such as imidazole compounds. Compounds etc. These thermally active latent epoxy resin hardeners can be used alone or in combination of two or more. Such a thermally active latent epoxy resin hardener is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and still more preferably 0.3 to 100 parts by weight of the epoxy resin. Use at a ratio of 5 parts by weight to 5 parts by weight.

As the phenol resin, a polymer having a phenolic hydroxyl group, such as a condensate of a phenol and an aldehyde, such as an alkylphenol, polyphenol, and naphthol, can be used without particular limitation. Specifically, phenol novolac resin, o-cresol novolac resin, p-cresol novolac resin, third butylphenol novolac resin, dicyclopentadiene cresol resin, poly-p-vinylphenol resin, Bisphenol A novolac resin, or modified products thereof.

The phenolic hydroxyl group contained in these phenol-based resins easily undergoes an addition reaction with the epoxy group of the epoxy resin by heating, and a hardened product having high impact resistance can be formed. Therefore, an epoxy resin and a phenol resin may be used together.

Examples of the energy ray-curable component include at least one component selected from the group consisting of an energy ray-curable polymer and an energy ray-curable monomer and oligomer in the adhesive layer 22 (B ).

The adhesive polymer component is formulated for the purpose of imparting moderate viscosity to the protective film-forming film 3 or improving the operability of the protective film-forming composite sheet 1. The weight average molecular weight of the binder polymer is usually in the range of 30,000 to 2 million, preferably 50,000 to 1.5 million, and particularly preferably 100,000 to 1 million. When the molecular weight is 30,000 or more, the film formation of the protective film formation film 3 is sufficient. When the molecular weight is 2 million or less, the compatibility with other components can be maintained well, and the film of the protective film formation film 3 can be uniformly performed. form. As such a binder polymer, for example, an acrylic polymer, poly Ester resins, phenoxy resins, urethane resins, silicone resins, rubber-based polymers, and the like, and acrylic polymers are particularly preferably used.

Examples of the acrylic polymer include a (meth) acrylate copolymer including a (meth) acrylate monomer and a structural unit derived from a (meth) acrylic acid derivative. Here, as the (meth) acrylate monomer, preferred are alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group, and more specifically, methyl (meth) acrylate, (Meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid derivative include (meth) acrylic acid, glycidyl (meth) acrylate, and hydroxyethyl (meth) acrylate.

In the above, if glycidyl group is introduced into an acrylic polymer using glycidyl methacrylate or the like as a structural unit, compatibility with the epoxy resin as the thermosetting component is improved, and after the protective film forming film 3 is hardened The glass transition temperature (Tg) becomes higher, and the heat resistance is improved. In addition, in the above, if a hydroxyl group is introduced into an acrylic polymer using a hydroxyethyl acrylate or the like as a structural unit, the adhesion to the workpiece or the adhesive physical properties can be controlled. When a glycidyl group is introduced into an acrylic polymer using glycidyl methacrylate or the like as a structural unit, the acrylic polymer or a phenoxy resin having an epoxy group has thermosetting properties. However, such a polymer having a thermosetting property corresponds to a polymer component of a binder in this embodiment, and is not a thermosetting component.

When an acrylic polymer is used as the binder polymer, the weight average molecular weight of the polymer is preferably 100,000 or more, particularly preferably 150,000 to 1 million. The glass transition temperature of the acrylic polymer is usually below 20 ° C, preferably about -70 ° C to 0 ° C, and has adhesiveness at normal temperature (23 ° C).

Regarding the blending ratio of the thermosetting component and the binder polymer component, when the binder polymer component is 100 parts by weight, the blending amount of the thermosetting component is preferably 50 parts by weight to 1500 parts by weight, and more preferably 70 to 1000 parts by weight, and more preferably 80 to 800 parts by weight. If a thermosetting component and an adhesive polymer component are blended in such a ratio, a moderate viscosity is exhibited before curing, a stable attaching operation can be performed, and a protective film having excellent film strength after curing can be obtained.

The protective film forming film 3 preferably contains a filler and / or a colorant. When the protective film forming film 3 contains a filler, the hardness of the cured protective film can be maintained high, and the moisture resistance can be improved. In addition, the gloss of the surface on which the protective film is to be formed may be adjusted to a desired value. Furthermore, the thermal expansion coefficient of the cured protective film can be made close to the thermal expansion coefficient of the semiconductor wafer, thereby reducing the warpage of the semiconductor wafer during processing. On the other hand, if the protective film-forming film 3 contains a filler and / or a colorant, laser printing with excellent visibility can also be realized.

Examples of the filler include silicon dioxide such as crystalline silicon dioxide, fused silicon dioxide, and synthetic silicon dioxide; or inorganic fillers such as alumina and glass balls. Among them, synthetic silicon dioxide is preferred, and in particular, the type of synthetic silicon dioxide that removes as much as possible the source of the α-rays, which is the main cause of malfunction of the semiconductor device, is the most suitable. The shape of the filler may be any of a spherical shape, a needle shape, and an irregular shape.

In addition, as the filler to be added to the protective film-forming film 3, a functional filler may be blended in addition to the inorganic filler described above. Examples of the functional filler include conductive fillers made of gold, silver, copper, nickel, aluminum, stainless steel, carbon, ceramics, or silver and nickel or aluminum for the purpose of imparting antistatic properties; Thermally conductive fillers such as gold, silver, copper, nickel, aluminum, stainless steel, silicon, germanium and other metal materials or alloys for the purpose of thermal conductivity.

As the colorant, known pigments such as inorganic pigments, organic pigments, and organic dyes can be used.

Examples of the inorganic pigments include carbon black, cobalt-based pigments, iron-based pigments, chromium-based pigments, titanium-based pigments, vanadium-based pigments, zirconium-based pigments, molybdenum-based pigments, ruthenium-based pigments, platinum-based pigments, and ITO ( Indium Tin Oxide (Indium Tin Oxide) based pigments, ATO (Antimony Tin Oxide) based pigments and the like.

Examples of the organic pigments and organic dyes include ammonium-based pigments, cyanine-based pigments, merocyanine-based pigments, ketoacid-based pigments, squaraine-based pigments, azulenium-based pigments, and polyoxine. Methyl-based pigments, naphthoquinone-based pigments, pyranium-based pigments, phthalocyanine-based pigments, naphthalocyanine-based pigments, naphtholide-based pigments, azo-based pigments, condensed azo-based pigments, indigo-based pigments, purple Cyclic ketone pigment, hydrazone pigment, dioxazine pigment, quinacridone pigment, isoindolinone pigment, quinoline yellow pigment, pyrrole pigment, thioindigo pigment, metal complex pigment (Metal salt dyes), dithiol metal complex pigments, indole phenol pigments, triallyl methane pigments, anthraquinone pigments, dioxazine pigments, naphthol pigments, methylimine Pigments, benzimidazolone pigments, dermatanone pigments, reducing pigments, and the like. In order to adjust the target light transmittance, these pigments or dyes can be appropriately mixed and used.

From the viewpoint of printability by laser light irradiation, it is preferable to use a pigment among the above, and it is more preferable to use an inorganic pigment. Among the inorganic pigments, carbon black is particularly preferred. Carbon black is usually black, and the portion removed by laser light irradiation appears white, so the contrast difference becomes large, so the visibility of the printed portion by laser is very good.

The blending amounts of the filler and the coloring agent in the protective film-forming film 3 may be appropriately adjusted so as to exert a desired effect. Specifically, the blending amount of the filler is generally preferably 40% to 80% by mass, and particularly preferably 50% to 70% by mass, relative to the total mass of the protective film forming film. In addition, colorants The blending amount is generally preferably 0.001% to 5% by mass, more preferably 0.01% to 3% by mass, and even more preferably 0.1% to 2.5% by mass relative to the total mass of the protective film-forming film.

The protective film forming film 3 may contain a coupling agent. By containing a coupling agent, the heat resistance of the protective film is not impaired after the protective film-forming film 3 is cured, and the adhesiveness and adhesion between the protective film and the workpiece can be improved, and the water resistance (humidity and heat resistance) can be improved. . As the coupling agent, a silane coupling agent is preferred in terms of its versatility and cost advantages.

Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) Ethyltrimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-amino group Propyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ- Ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, imidazolesilane, etc. These can be used individually by 1 type or in mixture of 2 or more types.

In order to adjust the cohesive force before hardening, the protective film-forming film 3 may contain a crosslinking agent such as an organic polyisocyanate compound, an organic polyimide compound, and an organic metal chelate compound. In addition, in order to suppress static electricity and improve the reliability of the wafer, the protective film forming film 3 may contain an antistatic agent. Furthermore, in order to improve the flame retardancy of the protective film and improve the reliability as a package, the protective film-forming film 3 may also contain flame retardants such as a phosphoric acid compound, a bromine compound, and a phosphorus-based compound.

That is, one form of the protective film-forming film 3 includes a group consisting of a hardening component, an adhesive polymer component, and a colorant, a filler, a coupling agent, a cross-linking agent, an antistatic agent, and a flame retardant, if necessary. At least one of the ingredients.

In order to effectively function as a protective film, the thickness of the protective film-forming film 3 is preferably 3 μm to 300 μm, more preferably 5 μm to 250 μm, and even more preferably 7 μm to 200 μm.

Here, when the protective film-forming film 3 is hardened to form a protective film while being in contact with the adhesive layer 22 in the adhesive sheet 2, the gloss value of the surface on the side of the adhesive sheet 2 in the protective film is preferably 25 or more. , Especially preferably 30 or more. The gloss value in this specification is a value measured using a gloss meter at a measurement angle of 60 ° in accordance with JIS Z8741. The gloss value formed on the surface of the protective film formed on the wafer is in the above-mentioned range, and the appearance is excellent, and the printability formed by laser printing is excellent.

3. Adhesive layer for fixture

The protective film-forming composite sheet 1 of this embodiment is provided with a jig adhesive layer 4 on a peripheral edge portion of the protective film-forming film 3 on the side opposite to the side of the adhesive sheet 2. By having the adhesive layer 4 for a jig as described above, it is possible to attach the protective sheet forming composite sheet 1 to a jig such as a ring frame without fixing the adhesive force of the protective film forming film 3 and securely fix it.

The adhesive layer 4 for jigs in this embodiment is formed in a ring shape, and may be formed of a single layer or may include multiple layers of two or more layers. In the case of multiple layers, a core material is preferably located in the middle.

From the viewpoint of the adhesive force to a jig such as a ring frame, the adhesive constituting the jig adhesive layer 4 is preferably made of a non-energy-ray-curable adhesive. As the non-energy-ray-curable adhesive, those having desired adhesion and re-peelability are preferred. For example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, or a urethane adhesive can be used. Adhesives, polyester-based adhesives, polyvinyl ether-based adhesives, etc. are preferably acrylic adhesives that are easy to control the adhesion and re-peelability.

As the core material, a resin film is generally used. Among them, a polyvinyl chloride-based film such as a polyvinyl chloride film and a vinyl chloride copolymer film is preferred, and a polyvinyl chloride film is particularly preferred. The polyvinyl chloride film has a property of being easily restored upon cooling even when softened by heating. The thickness of the core material is preferably 2 μm to 200 μm, and particularly preferably 5 μm to 100 μm.

From the viewpoint of adhesion to a jig such as a ring frame, the thickness of the jig adhesive layer 4 is preferably 5 μm to 200 μm, and more preferably 10 μm to 100 μm.

4. Release sheet

The protective film-forming composite sheet 1 may have a release sheet on the protective film-forming film 3 and the adhesive layer 4 for the jig (upper side in FIG. 1). A protective film-forming composite sheet 10 according to an embodiment of the present invention having a release sheet is shown in FIG. 4. With this release sheet 7, the protective film-forming film 3 and the jig adhesive layer 4 can be protected until the protective film-forming composite sheet 1 is used.

The configuration of the release sheet 7 is arbitrary, and examples thereof include those obtained by peeling a plastic film with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and polyolefin films such as polypropylene and polyethylene. . As the release agent, polysiloxane-based, fluorine-based, long-chain alkyl-based and the like can be used. Among these, polysiloxane based on inexpensive and stable performance is preferred. The thickness of the release sheet is not particularly limited, but is usually about 20 μm to 250 μm.

It is preferable that the composite sheet for forming a protective film is heated to a temperature of 10 ° C / min to 130 ° C at a temperature increase rate of 10 ° C / minute, and the temperature is maintained for 2 hours at a temperature of 0.01% or more and 6.0% or less. , The weight reduction rate is more preferably 3.0% or less, still more preferably 2.5% or less, and even more preferably 1.2% or less (the measurement method is shown in a test example described later). That is, the weight reduction rate of the composite sheet for forming a protective film is preferably 0.01% or more and 6.0% or less, more preferably 0.01% or more and 3.0% or less, still more preferably 0.01% or more and 2.5% or less, and particularly preferably It is 0.01% or more and 1.2% or less. Here, the composite sheet for forming a protective film is a composite sheet for forming a protective film which includes a base material, an adhesive layer, and a protective film forming film, and sequentially laminates the base material, the adhesive layer, and the protective film forming film. And it is set as the thing which does not contain a peeling sheet and an adhesive layer for jigs. By setting the weight reduction rate of the composite sheet for protective film formation to be within the above range, the composite sheet for protective film formation is not easily deformed when heated, and the composite sheet for protective film formation has excellent heat resistance suitable for the purpose for which it is used. . In addition, since the weight reduction rate of the composite film for forming a protective film is within the above range, when the composite sheet for forming a protective film is heated, almost no gas is generated from the composite sheet for forming a protective film, so that it can be suppressed. Deterioration of the composite sheet for forming a protective film. In addition, when the weight reduction rate of the protective film-forming composite sheet is within the above range, the adhesion between the protective film-forming film and the workpiece is unlikely to decrease.

5. Manufacturing method of composite sheet for forming protective film

The protective film-forming composite sheet 1 can be preferably produced by preparing a first laminated body including the protective film forming film 3, a second laminated body including the adhesive sheet 2, and an adhesive for a jig. After the third laminate of layer 4, a protective film is formed using the first laminate and the second laminate. The film 3 and the adhesive sheet 2 are laminated, and a third laminated body is further used to laminate the adhesive layer 4 for a jig, but it is not limited to this.

When manufacturing a 1st laminated body, the protective film formation film 3 is formed in the peeling surface (surface which has peelability; usually the surface which carried out the peeling process, but is not limited to this) of the 1st peeling sheet. Specifically, a coating agent for a protective film-forming film containing a curable adhesive constituting the protective film-forming film 3 and, if necessary, a solvent is further prepared, and a roll coater, a knife coater, and a roll knife are used. Coater, air knife coater, die coater, bar coater, gravure coater, curtain coater and other coaters, apply the aforementioned to the release surface of the first release sheet The coating agent is dried, and a protective film-forming film 3 is formed on the release surface of the first release sheet. Next, the exposed surface of the protective film forming film 3 is laminated on the exposed surface of the second release sheet and pressure-bonded to obtain a laminated body (first laminated body) in which the protective film forming film 3 is sandwiched between the two release sheets.

When manufacturing the second laminated body, the peeling surface of the third peeling sheet is coated with an adhesive containing the adhesive layer 22 and, if necessary, a coating agent for an adhesive layer further containing a solvent, and dried. 3 An adhesive layer 22 is formed on the release surface of the release sheet. Thereafter, the substrate 21 is pressure-bonded on the exposed surface of the adhesive layer 22 to obtain a laminated body (a second laminated body) including the adhesive sheet 2 and the release sheet containing the substrate 21 and the adhesive layer 22.

Here, when the adhesive layer 22 contains an energy ray-curable adhesive, the energy layer may be irradiated with the energy ray to harden the energy ray-curable adhesive. In addition, when the adhesive layer 22 includes a plurality of layers, and the layer in contact with the protective film forming film 3 includes an energy ray-curable adhesive, the contact layer may be irradiated with energy rays to harden the energy ray-curable adhesive.

As the energy rays, ultraviolet rays, electron beams, and the like are generally used. The irradiation amount of the energy ray varies according to the type of the energy ray. For example, in the case of ultraviolet rays, it is preferably 50 mJ / cm ² to 1000 mJ / cm ² in terms of light amount, particularly preferably 100 mJ / cm ² to 500 mJ / cm ² . In the case of the electron beam, it is preferably about 10 krad to 1000 krad.

When the adhesive layer 4 for a jig is a single layer, when manufacturing a 3rd laminated body, the adhesive layer 4 for a jig is formed on the peeling surface of a 1st release sheet. Specifically, the coating agent containing the adhesive agent which comprises the adhesive layer 4 for jigs, and the adhesive agent layer which further contains a solvent as needed is prepared, and it coats on the peeling surface of a 1st release sheet, and makes it Dry to form an adhesive layer 4 for a jig. Next, the exposed surface of the adhesive layer 4 for a jig is overlapped with the release surface of the second release sheet and pressure-bonded to obtain a laminated body (the third laminate) in which two release sheets sandwich the adhesive layer 4 for the jig. body).

When the adhesive layer 4 for a jig has a core material, when the third laminated body is produced, for example, a first adhesive layer for a jig is formed on the peeling surface of the first release sheet, and the first adhesive for the jig is formed. Core material is laminated on top of each other. In addition, The release surface of the 2 release sheet forms a second adhesive layer for a jig. Then, the second adhesive layer for the jig and the core material on the first adhesive layer for the jig were overlapped, and the two laminated bodies were pressed together. Thereby, a laminated body (third laminated body) obtained by sandwiching the adhesive layer 4 for a jig having a core material with two release sheets is obtained.

After the first laminated body, the second laminated body, and the third laminated body are obtained in this manner, the second release sheet in the first laminated body is peeled off, and the release sheet in the second laminated body is peeled off to expose the first laminated body. The protective film-forming film 3 and the adhesive layer 22 of the adhesive sheet 2 exposed in the second laminated body are overlapped and crimped (the fourth laminated body).

On the other hand, in the third laminated body, the first release sheet is retained and the inner peripheral edges of the second release sheet and the adhesive layer 4 for a jig are half-cut. The second peeling sheet and the adhesive layer 4 for jigs which are unnecessary portions (round portions) generated by half cutting may be appropriately removed. Then, the 1st peeling sheet is peeled from a 4th laminated body, and the exposed protective film formation film 3 and the adhesive agent layer 4 for jigs exposed in a 3rd laminated body are overlapped, and are pressure-bonded. After that, the first release sheet in the third laminated body was retained, and the outer peripheral edge of the protective film-forming composite sheet 1 was half-cut.

In this way, a protective film-forming composite sheet 10 having a release sheet 7 laminated on the protective film-forming composite sheet 1 is obtained. The protective film-forming composite sheet 1 includes: an adhesive sheet 2, and an adhesive layer is laminated on a substrate 21. 22; the protective film forms a film 3, which is laminated on the adhesive layer 22 side of the adhesive sheet 2; And the adhesive layer 4 for jigs is laminated on the peripheral edge portion of the protective film forming film 3 on the side opposite to the adhesive sheet 2. At this time, the release sheet 7 is laminated on the opposite side to the protective film forming film 3 in the jig adhesive layer 4.

The protective film-forming composite sheet 1 having such a configuration can make the protective film-forming film 3 and the pressure-sensitive adhesive sheet 2 the same size and shape. Therefore, the number of half-cutting steps can be reduced compared to the case where the size or shape is different. Simple manufacturing.

In addition, in the composite film 1 for forming a protective film having such a configuration, the outer periphery of the adhesive layer 4 for a jig for protrusions can be positioned at the same position as the entire outer periphery of the composite film 1 for forming a protective film. When a plurality of long stripped sheets (step films) of the protective film-forming composite sheet 1 according to this embodiment are wound and carried, there is an advantage that it is difficult to form so-called curl marks.

6. How to use the protective sheet forming composite sheet

Hereinafter, a method of manufacturing a wafer with a protective film from the semiconductor wafer as a work using the composite film 1 for forming a protective film according to this embodiment will be described as an example. First, as shown in FIG. 3, a protective film forming film 3 is attached to a semiconductor wafer 5, and a jig adhesive layer 4 is attached to a ring frame 6. When the protective film-forming film 3 is attached to the semiconductor wafer 5, the protective film-forming film 3 may be heated as needed to develop the adhesiveness.

Next, the protective film forming film 3 is cured to form a protective film. When the protective film-forming film 3 is a thermosetting adhesive, the protective film-forming film 3 is heated at a specific temperature for a suitable time and then cooled. In this case, since the composite sheet 1 for forming a protective film according to this embodiment can effectively suppress sag, it does not hinder subsequent steps.

If necessary, laser printing may be performed on the protective film-forming film 3 before curing or the protective film-forming film 3 (protective film) after curing. After that, the semiconductor wafer 5 is cut according to a conventional method to obtain a wafer having a protective film (wafer with a protective film). Then, if necessary, the adhesive sheet 2 is extended in a planar direction, and a wafer with a protective film is picked up from the adhesive sheet 2. Since the composite sheet 1 for forming a protective film according to this embodiment has an adhesive layer 22, it is possible to suppress wafer bounce during the dicing. In addition, since the adhesive sheet 2 of the protective film-forming composite sheet 1 of this embodiment has moderate flexibility, it can be stretched or picked up well.

The embodiments described above are described for easier understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiments also includes all design changes or equivalents belonging to the technical scope of the present invention.

For example, the adhesive layer 4 for a jig may be composed of two layers including a substrate and an adhesive layer. In this case, it is preferred that the protective film-forming film 3 exhibiting adhesiveness be adhered to the above-mentioned base material, and be used in a jig such as a ring frame. It is configured by attaching the above-mentioned adhesive layer. The adhesive sheet 4 for a jig may be omitted from the composite sheet 1 for forming a protective film. At this time, the protective film-forming film 3 is preferably formed to have a smaller diameter than the adhesive sheet 2 so that the adhesive layer 22 of the adhesive sheet 2 is exposed, and the exposed adhesive layer 22 is attached to a ring frame or the like. With.

[Example]

Hereinafter, the present invention will be described more specifically using examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

In Example 1, a composite sheet 1 for forming a protective film as shown in FIG. 1 was produced as follows.

(1) Production of a first laminated body including a protective film forming film

The following components (a) to (g) were mixed and diluted with methyl ethyl ketone so that the solid content concentration became 50% by mass to prepare a coating agent for a protective film forming film.

(a) Binder polymer: (meth) acrylate copolymer (10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 2-hydroxyethyl acrylate 15 parts by mass of a copolymer obtained by copolymerization, weight average molecular weight: 800,000, glass transition temperature: -1 ° C) 150 parts by mass (in terms of solid content, the same applies hereinafter)

(b-1) Thermosetting component: 60 parts by mass of bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER828", epoxy equivalent: 184 g / eq to 194 g / eq)

(b-2) Thermosetting component: 10 parts by mass of bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER1055", epoxy equivalent of 800 g / eq to 900 g / eq)

(b-3) Thermosetting component: Dicyclopentadiene epoxy resin (manufactured by Dainippon Ink Chemical Industry Co., Ltd., product name "Epiclon HP-7200HH", epoxy equivalent is 255g / eq ~ 260g / eq 30 parts by mass

(c) 2 parts by mass of thermally active latent epoxy resin hardener: dicyandiamine (manufactured by ADEKA Co., Ltd .: Adeka Hardener EH3636AS, active hydrogen content: 21 g / eq)

(d) Hardening accelerator: 2 parts by mass of 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., product name "Curezol 2PHZ")

(e) Filler: 320 parts by mass of silicon dioxide filler (manufactured by Admatechs Co., Ltd., product name "SC2050MA", average particle diameter: 0.5 μm)

(f) Colorant: 1.2 parts by mass of carbon black (manufactured by Mitsubishi Chemical Corporation, product name "# MA650", average particle diameter: 28 nm)

(g) Silane coupling agent: (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name "KBM-403") 2 parts by mass

A first release sheet (manufactured by LINTEC Co., Ltd. under the product name "SP-PET381031" was prepared by forming a silicone-based release agent layer on one side of a polyethylene terephthalate (PET) film having a thickness of 38 µm. "), And a second release sheet (manufactured by LINTEC Corporation, product name" SP-PET381130 ") formed by forming a polysiloxane-based release agent layer on one side of a PET film having a thickness of 38 µm.

First, on the release surface of the first release sheet, the protective coating film-forming coating agent is applied and dried using a knife coater so that the thickness of the finally obtained protective film-forming film becomes 25 μm. A protective film is formed. Thereafter, the release surface of the second release sheet was superposed on the protective film-forming film, and the two were bonded together to obtain a laminated body including the first release sheet, the protective film-forming film (thickness: 25 μm), and the second release sheet. The laminated body is a long strip, and is wound to form a rolled body.

(2) Production of the second laminated body including the adhesive sheet

The following components (h) and (i) were mixed and diluted with methyl ethyl ketone so that the solid content concentration became 25% by mass to prepare a coating agent for an adhesive layer.

(h) Adhesive base agent: (meth) acrylate copolymer (copolymerized 60 parts by mass of 2-ethylhexyl acrylate, 30 parts by mass of methyl methacrylate, and 10 parts by mass of 2-hydroxyethyl acrylate The obtained copolymer has a weight average molecular weight: 600,000) 100 parts by mass

(i) Crosslinking agent: 20 parts by mass of trimethylolpropane xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., product name "Takenate D110N")

As a release sheet, a release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") was prepared by forming a polysiloxane-based release agent layer on one side of a PET film having a thickness of 38 µm.

In addition, as the base material, the load expansion and contraction ratio is 98.6% in the MD direction and 99.1% in the CD direction, the loadless expansion and contraction ratio is 99.0% in the MD direction and 98.8% in the CD direction, and the tensile elastic modulus is 320 MPa in the MD direction and 290 MPa in the CD direction. And a polypropylene film (thickness: 80 μm) having a melting point of 156 ° C. The methods for measuring the load expansion and contraction, no load expansion and contraction, tensile elastic modulus, and melting point are as shown in the test examples described later (the same applies hereinafter).

First, on the release surface of the release sheet, a knife coater was used to coat the aforementioned coating agent for an adhesive layer so that the thickness of the finally obtained adhesive layer became 5 μm, and dried to form an adhesive. Floor. After that, the substrate is bonded to the adhesive layer to obtain a second laminated body including an adhesive sheet and a release sheet. The adhesive sheet contains the substrate and the adhesive layer. The laminate is long. Thereafter, the laminated body is wound to form a rolled body.

(3) Production of the third laminated body including the adhesive layer 4 for jigs

The following components (j) and (k) were mixed and diluted with toluene so that the solid content concentration became 15% by mass to prepare a coating agent for an adhesive layer.

(j) Adhesive base agent: (meth) acrylate copolymer (copolymer obtained by copolymerizing 69.5 parts by mass of butyl acrylate, 30 parts by mass of methyl acrylate, and 0.5 parts by mass of 2-hydroxyethyl acrylate, weight Average molecular weight: 500,000) 100 parts by mass

(k) Cross-linking agent: 5 parts by mass of toluene diisocyanate-based cross-linking agent (manufactured by Toyochem Co., Ltd., product name "BHS8515")

A first release sheet and a second release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") formed by forming a polysiloxane-based release agent layer on one side of a PET film having a thickness of 38 μm, and prepared as A polyvinyl chloride film for the core material (manufactured by Okamoto Co., Ltd., thickness: 50 μm).

First, on the peeling surface of the first peeling sheet, a knife coater was used to coat the coating agent for the adhesive layer so that the thickness of the finally obtained adhesive layer became 5 μm, and dried to form The first adhesive layer. Thereafter, the core material is bonded to the first adhesive layer to obtain a laminated body A including the core material, the first adhesive layer, and the first release sheet. The laminated body A is a long strip, and is wound to form a rolled body.

Next, on the release surface of the second release sheet, a knife coater was used to apply the coating agent for the adhesive layer so that the thickness of the finally obtained adhesive layer became 5 μm, and dried to form The second adhesive layer. Then, the exposed surface of the core material in the laminated body A is bonded to the second adhesive layer to obtain the first release sheet / first adhesive layer / core material / second adhesive layer / second release sheet. The third laminated body. The laminated body is a long strip, and is wound to form a rolled body.

(4) Production of the fourth laminated body

The second release sheet was peeled from the first laminate obtained in the above (1), and the protective film-forming film was exposed. On the other hand, the peeling sheet was peeled from the 2nd laminated body obtained by said (2), and the adhesive layer was exposed. The first laminated body and the second laminated body were bonded such that the protective film-forming film contacted the adhesive layer to obtain an adhesive sheet, a protective film-forming film, and a first release sheet including a base material and an adhesive layer. The fourth laminated body.

(5) Fabrication of composite sheet for protective film formation

The second release sheet was peeled from the third laminate obtained in the above (3), and the first peeling sheet was retained, and the inner peripheral edge of the adhesive layer for the jig was cut in half to remove the inner circular portion. At this time, the diameter of the inner peripheral edge of the adhesive layer for jigs was set to 170 mm.

The first release sheet was peeled from the fourth laminated body obtained in the above (4), and the exposed protective film-forming film was adhered to the fixture exposed in the third laminated body. The agent layers are overlapped and crimped. After that, the first release sheet in the third laminated body was retained, and the outer peripheral edge of the composite sheet for forming a protective film was cut in half to remove the outer part. At this time, the diameter of the outer peripheral edge of the protective film-forming composite sheet was 205 mm.

In this way, a composite sheet for forming a protective film is obtained, which includes: an adhesive sheet formed by laminating an adhesive layer (thickness: 5 μm) on a base material; a protective film forming film, which is laminated on the adhesive layer side of the adhesive sheet; a ring The adhesive layer for a jig is layered on the peripheral edge portion on the side opposite to the adhesive sheet in the protective film-forming film; and the release sheet is layered on the opposite side of the protective film-forming film in the adhesive layer for the jig. .

[Example 2]

As the base material, the load expansion and contraction ratio is 96.3% in the MD direction and 99.6% in the CD direction, the loadless expansion and contraction ratio is 98.8% in the MD direction and 99.0% in the CD direction, the tensile elastic modulus is 190 MPa in the MD direction and 170 MPa in the CD direction, and the melting point is A protective film-forming composite sheet was produced in the same manner as in Example 1 except for a polypropylene film (thickness: 80 μm) at 154 ° C.

[Example 3]

As the base material, the load expansion and contraction ratio is 99.7% in the MD direction and 102.8% in the CD direction, the loadless expansion and contraction ratio is 99.3% in the MD direction and 99.4% in the CD direction, and the tensile elastic modulus is 490 MPa in the MD direction and 450 in the CD direction. Except for a polypropylene film (thickness: 80 μm) having a MPa and a melting point of 131 ° C., a composite sheet for forming a protective film was produced in the same manner as in Example 1.

[Example 4]

As the substrate, a load expansion and contraction rate of 101.4% in the MD direction and 100.4% in the CD direction, a loadless expansion and contraction rate of 99.6% in the MD direction and 99.6% in the CD direction, a tensile elastic modulus of 630MPa in the MD direction and 620MPa in the CD direction, and a melting point of Except for a polypropylene film (thickness: 80 μm) at 163 ° C., a composite sheet for forming a protective film was produced in the same manner as in Example 1.

[Comparative Example 1]

As a base material, a load expansion and contraction rate of 155.0% in the MD direction / 195.0% in the CD direction, a loadless expansion and contraction rate of 97.0% in the MD direction and 97.8% in the CD direction, a tensile elastic modulus of 220 MPa in the MD direction and 210 MPa in the CD direction, and a melting point of Except for a polypropylene film (thickness: 80 μm) at 118 ° C., a composite sheet for forming a protective film was produced in the same manner as in Example 1.

[Comparative Example 2]

As the base material, a load expansion ratio of 93.9% in the MD direction / 129.8% in the CD direction, a load expansion ratio of 94.0% in the MD direction / 97.3% in the CD direction, and a tensile elastic modulus of 130 MPa in the MD direction and 120 in the CD direction are used. A protective film-forming composite sheet was produced in the same manner as in Example 1 except that a polypropylene film (thickness: 80 μm) having a MPa and a melting point of 124 ° C. was used.

[Test Example 1] <Measurement of Load Stretch Ratio>

The substrates used in the examples and comparative examples were cut into a size of 22 mm short side and 110 mm long side so that the short side became the CD direction and the long side became the MD direction, and this was set as a test piece in the MD direction. The test piece was marked by setting 100 mm of the central portion in the longitudinal direction of the length of 110 mm as the measurement pitch, and a holder having a mass of 2.2 g was mounted on both ends of the test piece in the longitudinal direction (5 mm portion of the end portion). .

Using a holder, the test piece was suspended in an oven. The load on the test piece at this time is the mass portion of the lower holder, that is, 0.1 g / mm. After heating in the oven at 130 ° C. and 30% RH for 2 hours, the test piece was taken out of the oven and cooled to 23 ° C. After that, the measurement pitch marked on the test piece was measured again, and the load expansion and contraction (%) of the substrate was calculated according to the following formula. The results are shown in Table 1.

Load expansion and contraction (%) = (measurement interval after heating / measurement interval before heating) × 100

In addition, the substrates used in the examples and comparative examples were cut into a size of 22 mm short side and 110 mm long side so that the short side became the MD direction and the long side became the CD direction, and this was used as a test piece in the CD direction. for In this test piece in the CD direction, the load expansion ratio (%) was also calculated in the same manner as described above. The results are shown in Table 1.

[Experiment 2] <Measurement of no-load expansion and contraction>

In the above-mentioned measurement of load elongation (Test Example 1), except that the lower clamp was not attached to the test piece, the elongation (%) was calculated in the same manner as in Test Example 1, and this was set to no load. Stretch ratio. The results are shown in Table 1.

[Test Example 3] <Measurement of Tensile Elastic Modulus>

The substrates used in the examples and comparative examples were cut into 15 mm × 140 mm test pieces, and the tensile elastic modulus (Young's modulus) at 23 ° C. was measured in accordance with JIS K7127: 1999. Specifically, the test piece was pulled at a speed of 200 mm / min in a tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N") after setting the chuck pitch to 100 mm. Tensile test to determine the tensile elastic modulus (MPa). The measurement of the tensile elastic modulus was performed on both the MD direction and the CD direction of the substrate. The results are shown in Table 1.

[Test Example 4] <Measurement of Melting Point>

Using a thermogravimetric measuring device (manufactured by PerkinElmer, product name "Pyris1"), the melting points of the substrates used in the examples and comparative examples were measured. Specifically, the substrate is heated from 50 ° C at 10 ° C to 250 ° C per minute, and DSC (Differential Scanning Calorimetry, Differential scanning calorimetry) measurement, and the temperature at which the endothermic peak was observed was set as the melting point. The results are shown in Table 1.

[Test Example 5] <Relaxation Evaluation>

The release sheet was peeled from the protective film-forming composite sheet manufactured in the examples and comparative examples, and the obtained protective film-forming composite sheet was attached to a polysiloxane wafer (# 2000 polishing, outer periphery) as shown in FIG. 3. Diameter: 6 inches, thickness: 350 μm, mass: 14 g) and ring frame (made of stainless steel, inner diameter 195 mm). In this state, the protective film-forming film was hardened by heating in an environment of 130 ° C for 2 hours, and then cooled to room temperature.

Then, the difference between the height of the lower end surface of the protective film forming composite sheet on the lower side of the ring frame and the height of the lower end surface of the protective film forming composite sheet on the lower side of the semiconductor wafer (sink amount; mm ) And evaluated as slack. The evaluation criteria are as follows. The results are shown in Table 1.

A: Less than 0.5mm

B: 0.5mm or more and less than 2.0mm

C: 2.0mm or more

Among the results described above, the protective sheet-forming composite sheet systems of Comparative Examples 1 and 2 were evaluated as B or C. Since the slack was large, the pick-up force was not evaluated.

[Test Example 6] <Evaluation of Suitability of Cutting Device>

The composite sheet for forming a protective film with a polysiloxane wafer and a ring frame (after the hardening step) produced in the above Test Example 5 was adsorbed on an adsorption table of a cutting device (manufactured by DISCO Corporation, product name "DFD651") . At this time, it is judged whether or not a poor adsorption occurs due to the slackness of the protective film-forming composite sheet, and the suitability of the cutting device is evaluated using the following criteria. The results are shown in Table 1.

A: Adsorption without problems, fully fixed and cuttable

B: Poor adsorption occurs and cutting cannot be performed

[Test Example 7] <Pickup Force Evaluation>

The polysiloxane wafer with a protective film for forming a protective film with a polysiloxane wafer and a ring frame evaluated as A in the above Test Example 5 was cut into a wafer size of 5 mm × 5 mm to obtain a protective film. Wafer. Then, from the base material side of the composite sheet for forming a protective film, a needle is used for top-up, and the wafer with the protective film is picked up. At this time, the force (N) required for pickup was measured using a push-pull meter (manufactured by Aikoh Engineering Co., Ltd., product name "RX-1"). The pick-up force (N) was set as the average value of the measured values of 20 wafers, and the pick-up force was evaluated by the following criteria. The results are shown in Table 1.

A: Below 4.0N

B: More than 4.0N and 5.0N or less

C: more than 5.0N

[Test Example 8] <Evaluation of weight reduction rate of base material>

Using a thermogravimetric analysis device (manufactured by Shimadzu Corporation: DTG-60), the time taken to raise the base material used in the examples and comparative examples to 130 ° C at a temperature increase rate of 10 ° C / min and hold at this temperature for 2 hours was measured. Point weight reduction rate. This weight reduction rate can be calculated | required by the following calculation formula.

Weight reduction rate [%] = [(weight before heating-weight after heating) / weight before heating] × 100

The results are shown in Table 1.

[Test Example 9] <Evaluation of weight reduction rate of composite sheet for protective film formation>

Using a thermogravimetric analysis device (manufactured by Shimadzu Corporation: DTG-60), the following protective film-forming composite sheets were produced according to the examples and comparative examples, which consisted of a substrate, an adhesive layer, and a protective film-forming film, and were sequentially laminated. The substrate, the adhesive layer, and the protective film are formed into a film, and the release sheet and the adhesive layer for a jig are not included. The weight reduction rate was measured at the time point when the composite sheet for forming a protective film was heated to 130 ° C. at a temperature increase rate of 10 ° C./minute and maintained at the temperature for 2 hours. This weight reduction rate can be calculated | required by the following calculation formula.

Weight reduction rate [%] = [(weight before heating-weight after heating) / weight before heating] × 100

The results are shown in Table 1.

According to Table 1, it can be seen that the composite sheet for forming a protective film produced in the examples hardly relaxes after being subjected to the heating and cooling steps, and can be well cut and picked up.

[Industrial availability]

The composite film for forming a protective film of the present invention is suitably used for manufacturing a wafer having a protective film from a semiconductor wafer.

Claims (6)

A composite sheet for forming a protective film includes: an adhesive sheet formed by laminating an adhesive layer on one side of a substrate; and a protective film forming film laminated on the adhesive layer side of the adhesive sheet; When a load of 0.1g / mm is applied to the material and heated at 130 ° C for 2 hours and cooled to 23 ° C, the longitudinal and transverse expansion and contraction ratios of the aforementioned substrate with respect to the aforementioned before and after heating are both 95% to 103% The tensile elastic modulus of the aforementioned substrate at 23 ° C in the longitudinal direction and the transverse direction are 100 MPa to 700 MPa. The protective film-forming composite sheet according to claim 1, wherein the substrate is a polypropylene film. The protective film-forming composite sheet according to claim 1 or 2, wherein the thickness of the substrate is 50 μm to 200 μm. The protective film-forming composite sheet according to claim 1 or 2, further comprising an adhesive layer for a jig, which is laminated on a peripheral edge portion of the protective film-forming film opposite to the side of the adhesive sheet. The protective film-forming composite sheet according to claim 1 or 2, comprising a release sheet laminated on the protective film-forming film. The protective film-forming composite sheet according to claim 1 or 2, wherein the protective film-forming film is a layer formed on a semiconductor wafer or a semiconductor wafer formed by dicing the semiconductor wafer.