TWI741336B - Composite sheet for forming protective film - Google Patents

Abstract

A composite sheet for forming a protective film of the invention is a composite sheet for forming a protective film 3 including a supporting sheet 4 and a protection layer forming film 1 which is laminated on a first surface of the supporting sheet 4, wherein the arithmetic average roughness (Ra1) of a second surface of the supporting film 4 is 0.2µm or more and the arithmetic average roughness (Ra2) of the second surface of the supporting film 4 after heating the supporting film 4 at 130C° for two hours is 0.25µm or less.

Description

Composite sheet for forming protective film

The present invention is a composite sheet for forming a protective film, which can form a protective film on a workpiece such as a semiconductor wafer, or a processed product (for example, a semiconductor wafer) obtained by processing the aforementioned workpiece.

This case claims priority based on Japanese Patent Application No. 2014-106757 filed on May 23, 2014, and its content is used here.

In recent years, semiconductor devices have been manufactured by a mounting method called a face-down method. In this method, when mounting a semiconductor wafer having a circuit surface on which electrodes such as bumps are formed, the circuit surface side of the semiconductor wafer is bonded to a chip mounting portion such as a lead frame. Therefore, a structure in which the inner surface side of the semiconductor wafer where no circuit is formed is exposed to the outside.

Therefore, in order to protect the semiconductor wafer, a protective film containing a thermosetting organic material is formed more than the inner surface side of the semiconductor wafer. Usually, in order to indicate the product number of the aforementioned semiconductor chip, etc., characters are printed on this protective film. The printing method at this time generally uses the laser marking method (laser printing) in which the protective film is irradiated with laser light.

Patent Document 1 to Patent Document 3 respectively disclose a protective film forming/cutting integrated sheet (composite sheet for protective film formation) in which a protective film forming layer (protective film forming film) capable of forming the aforementioned protective film is formed on an adhesive sheet. In these protective film forming/cutting integrated sheets, the protective film forming film is cured by heat treatment to form the aforementioned protective film. That is, with the aforementioned protective film forming/dicing integrated sheet, semiconductor wafers can be diced and a protective film can be formed for the semiconductor chip, thereby obtaining a semiconductor chip with a protective film.

In addition, when manufacturing processed objects including semiconductor wafers and other sheet-like objects from workpieces such as semiconductor wafers, conventionally, while spraying liquid for cleaning, etc. on the workpiece, the workpiece is cut with a rotating blade to obtain the sheet-like objects. The cutter cutting process. However, in recent years, invisible laser wafer dicing (STEALTH DICING (registered trademark); the same applies below) processing that can be dry-divided into slices has been adopted (Patent Document 3).

For example, Patent Document 4 discloses an invisible laser wafer dicing method, in which a laminated adhesive sheet (the adhesive sheet composed of a base material and an adhesive layer is laminated with two layers) is attached to an extremely thin semiconductor wafer, and the laminated adhesive sheet side The semiconductor wafer is irradiated with laser light through the aforementioned laminated adhesive sheet, and the modified portion is formed inside the semiconductor wafer to expand the adhesive sheet, thereby dividing the semiconductor wafer along the cutting line to produce the semiconductor wafer.

[Prior Technical Literature]

[Patent Literature]

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

Patent Document 2: Japanese Patent Application Publication No. 2012-33637.

Patent Document 3: Japanese Patent Application Publication No. 2011-151362.

Patent Document 4: Japanese Patent No. 3762409.

Patent Document 5: Japanese Patent Laid-Open No. 2007-123404.

When the workpiece is irradiated with laser light as described above, since the laser light needs to penetrate the adhesive sheet to reach the protective film or the workpiece, the adhesive sheet must have laser light penetration.

In addition, in order to protect the aforementioned protective film formation film, a release sheet is often laminated on the opposite side of the adhesive sheet of the protective film formation film in the composite sheet for protective film formation. When the aforementioned composite sheet for protective film formation is pulled out from the roll state, the wound adhesive sheet is on the opposite side of the protective film formation film The protective film of the release sheet and the two sides of the opposite side of the film formed by the release sheet will be closely adhered to produce blocking and cause defects to be pulled out by the roller, or the adhesive sheet will be transferred to the wound release sheet and cannot be attached to the workpiece. .

The present invention was researched in view of the foregoing circumstances, and the purpose of the present invention is to provide a composite sheet for forming a protective film, which can suppress adhesion when the composite sheet for forming a protective film is pulled out from the state of being wound into a roll, and when irradiating laser light The laser light has excellent penetrability.

In order to achieve the foregoing object, the first embodiment of the present invention provides a composite sheet for forming a protective film (Invention 1), which has a support sheet and a protective film forming film laminated on the first surface side of the support sheet. The arithmetic mean roughness (Ra1) of the second surface of the support sheet is 0.2μm or more. After heating the support sheet at 130°C for 2 hours, the arithmetic mean roughness (Ra2) of the second surface of the support sheet is 0.25μm or less. Preferably, the storage elastic modulus of the substrate at 130° C. is 1 MPa to 100 MPa, and it is preferable that the arithmetic average roughness (Ra2) of the second surface of the support sheet after heating is smaller than the arithmetic average roughness (Ra1). In addition, in this specification, "sheet" includes concepts such as long strips.

According to the aforementioned invention (Invention 1), when the composite sheet for forming a protective film is wound into a roll shape, the second surface of the support sheet and the member contacting the second surface of the support sheet (for example, the protective film forming film is provided with If the peeling sheet is a peeling sheet, if the peeling sheet is not provided, it is a protective film forming film, etc.) It is not easy to adhere, and when the protective film forming composite sheet is pulled out from the wound roll shape, it is not easy to cause adhesion. In addition, when the laser light is irradiated from the second surface side of the support sheet, the laser light will not be scattered by the unevenness of the second surface of the support sheet and penetrate the support sheet, and can efficiently reach the protection formed by the hardening of the protective film. Films or workpieces (semiconductor wafers) have excellent laser light penetration.

In the aforementioned invention (Invention 1), it is preferable that the support sheet includes a substrate and an adhesive layer laminated on the first surface side of the substrate on the side of one side of the substrate; or the support sheet Including substrate (Invention 2).

In the aforementioned invention (Invention 2), it is preferable that the storage elastic modulus of the aforementioned substrate at 130°C is 1 MPa to 100 MPa (Invention 3).

In the aforementioned inventions (Invention 2 to Invention 3), it is preferable that the substrate has a light transmittance of 40% or more at a wavelength of 1064 nm after the heating (Invention 4).

In the aforementioned inventions (Inventions 2 to 4), it is preferable that the substrate has a light transmittance of 532 nm after heating of 40% or more (Invention 5).

In the aforementioned inventions (Inventions 2 to 5), it is preferable that the aforementioned substrate is a film composed of a copolymer of ethylene and propylene (Invention 6).

In the aforementioned inventions (Inventions 1 to 6), it is preferable that the composite sheet for forming a protective film has an adhesive layer for a jig, and the adhesive layer for a jig is laminated on the protective film forming film opposite to the side of the support sheet. Side edge part (Invention 7).

In the aforementioned inventions (Invention 1 to Invention 7), it is preferable to have a release sheet, and the release sheet is laminated on the protective film forming film (Invention 8).

In the aforementioned inventions (Inventions 1 to 8), it is preferable that the aforementioned protective film forming film is a layer in which a protective film is formed on a semiconductor wafer or a semiconductor wafer obtained by dicing a semiconductor wafer (Invention 9).

The composite sheet for forming a protective film of the present invention can suppress adhesion that occurs when the composite sheet for forming a protective film is pulled out from a rolled state, and has excellent laser light penetration when irradiated with laser light.

1: Protective film forming film

101: round

3. 3A: Composite sheet for forming protective film

4: Support film

41: Substrate

42: Adhesive layer

401: round

402: Arc

403: straight line

5: Adhesive layer for jigs

6: Peel off sheet

7: Semiconductor wafer

8: Ring frame

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 use example of a composite sheet for forming a protective film according to an embodiment of the present invention, and specifically is a cross-sectional view showing a laminated structure.

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

Fig. 4 is a plan view of a composite sheet for forming a protective film produced in the embodiment.

Hereinafter, embodiments of the present invention will be described.

Fig. 1 is a cross-sectional view of a composite sheet for forming a protective film according to an embodiment of the present invention. As shown in FIG. 1, the composite sheet 3 for forming a protective film of the present embodiment is composed of: a support sheet 4; 1) side; and the jig adhesive layer 5, which is laminated on the edge portion of the protective film forming film 1 on the opposite side of the support sheet 4. The adhesive layer 5 for jigs is a layer for adhering the composite sheet 3 for forming a protective film to jigs such as a ring frame. In addition, the composite sheet 3 for forming a protective film of the present embodiment has a release sheet 6 on the protective film forming film 1 and the adhesive layer 5 for jigs (on the opposite side of the support sheet 4). This peeling sheet 6 is peeled and removed when the composite sheet 3 for forming a protective film is used, and it is not an essential component of the composite sheet 3 for forming a protective film.

The composite sheet 3 for forming a protective film of the present embodiment is used to adhere to the work while processing the work to maintain the work, and to form a protective film on the work or a processed product obtained by processing the work. The aforementioned protective film is composed of a protective film forming film 1, preferably a cured protective film forming film 1.

For example, the composite sheet 3 for forming a protective film of this embodiment is used to hold the semiconductor wafer when the semiconductor wafer as a workpiece is cut, and to cut the resulting semiconductor wafer The protective film is formed on the semiconductor wafer, but it is not limited to this. The support sheet 4 of the composite sheet 3 for forming a protective film at this time is generally called a dicing sheet.

The composite sheet 3 for forming a protective film of this embodiment is usually wound in a long roll shape, and is used in a roll-to-roll system.

1. Support film

The structure of the support sheet 4 of the composite sheet 3 for forming a protective film of this embodiment includes a base material 41; In the upper side). In this specification, the surface on the side of the protective film forming film 1 in the support sheet 4 is referred to as the "first surface", and the surface on the opposite side (the lower surface in FIG. 1) is referred to as the "second surface". In the support sheet 4, the adhesive layer 42 is laminated on the first surface side of the support sheet 4, and the base material 41 is laminated on the second surface side of the support sheet 4.

1-1. Substrate

The surface of the base material 41 on the opposite side of the adhesive layer 42 (hereinafter referred to as "the back surface of the base material 41." The back surface of the base material 41 is the second surface of the support sheet 4.) has an arithmetic average roughness (Ra1) of 0.2 Above μm. After the base material 41 is heated at 130°C for 2 hours and then cooled to room temperature (hereinafter referred to as "after heating"), the arithmetic average roughness (Ra2) of the back surface of the base material 41 is 0.25 μm or less. In addition, the arithmetic average roughness (Ra1) of the back surface of the substrate 41 is the arithmetic average roughness of the back surface of the substrate 41 before heating at 130°C for 2 hours, and is hereinafter referred to as "arithmetic average roughness before heating (Ra1)" . The arithmetic average roughness (Ra1) before heating and the arithmetic average roughness (Ra2) after heating are measured in accordance with JIS B0601:2001, and the detailed measurement method is shown in the test example described later.

In addition, the conditions of the aforementioned heat treatment (130°C, 2 hours) are usually the heat treatment conditions for thermally curing the protective film forming film 1, which is heating when the rolled composite sheet 3 for protective film formation is drawn out. Before, it is heated after being irradiated with laser light for laser printing or invisible laser wafer cutting. However, the aforementioned heating treatment is not necessarily a treatment for thermally curing the protective film forming film 1. For example, when the protective film forming film 1 is energy ray curable, another heating treatment may be performed.

By setting the arithmetic mean roughness (Ra1) of the back surface of the base material 41 before heating to 0.2 μm or more, in the wound state, the back surface of the base material 41 and the surface of the release sheet 6 on the opposite side of the protective film forming film 1 The two are not easy to connect closely. Thereby, when the composite sheet 3 for forming a roll-shaped protective film which is wound is pulled out, it is difficult to produce adhesion|attachment. Therefore, poor pull-out caused by adhesion can be suppressed, or the support sheet 4 can be prevented from sticking to the wound release sheet 6 and unable to stick to the workpiece.

From the foregoing viewpoint, the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating is preferably 0.25 μm or more, and more preferably 0.30 μm or more.

Here, the upper limit of the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating is preferably 1.0 μm or less, more preferably 0.8 μm or less, and still more preferably 0.7 μm or less. If the arithmetic average roughness (Ra1) before heating exceeds 1.0 μm, it may be difficult to achieve the aforementioned arithmetic average roughness (Ra2) after heating.

That is, the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating is preferably 0.25 μm to 1.0 μm, more preferably 0.30 μm to 0.7 μm.

In addition, by making the arithmetic mean roughness (Ra2) of the back surface of the substrate 41 after heating obtained under the aforementioned conditions to be 0.25 μm or less, when the laser light is irradiated from the back side of the substrate 41, the laser light will not be affected by the substrate 41. The irregularities on the back of 41 are scattered and penetrate the support sheet 4, which can efficiently reach the protective film or workpiece (semiconductor wafer) formed by the hardening of the protective film forming film 1, and has excellent laser light penetration. Therefore, in addition to the excellent laser printability and the formation of highly recognizable prints, the invisible laser wafer dicing also has excellent work piece separation.

From the foregoing viewpoints, the arithmetic average roughness (Ra2) of the back surface of the substrate 41 after heating is preferably 0.20 μm or less, and more preferably 0.10 μm or less.

Here, the lower limit of the arithmetic average roughness (Ra2) after heating on the back surface of the base material 41 is not particularly limited as long as it satisfies the arithmetic average roughness (Ra1) before heating. However, it is usually 0.001 μm or more, preferably 0.01 μm or more.

That is, the arithmetic average roughness (Ra2) of the back surface of the substrate 41 after heating is preferably 0.001 μm to 0.20 μm, more preferably 0.01 μm to 0.10 μm.

In addition, in the base material 41, the arithmetic average roughness (Ra2) after heating of the back surface of the base material 41 under the aforementioned conditions is preferably smaller than the arithmetic average roughness (Ra1) before heating. By setting in this way, both the adhesion suppression effect before heating and the laser light penetration after heating are excellent.

The method of adjusting the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating is not particularly limited, but it can generally be achieved by changing the surface roughness of the roller used in the film formation of the resin film constituting the base material 41 and sandblasting. It is adjusted by processing, or by heating and melting and blending a flattening filler.

In addition, as a method of adjusting the arithmetic mean roughness (Ra2) of the heated back surface of the base material 41, it is preferable that the base material 41 is composed of a resin film (a film made of a resin-based material as the main material) whose melting point is within a specific range. It is more preferable to be composed of a resin film with a melting point in a specific range and a storage elastic modulus of 130°C in a specific range.

The melting point of the substrate 41 is preferably 90°C to 180°C, more preferably 100°C to 160°C, and still more preferably 110°C to 150°C. By setting the melting point of the base material 41 within the aforementioned range, it is easy to adjust the arithmetic mean roughness (Ra2) of the back surface of the base material 41 after heating to the aforementioned range. If the melting point of the base material 41 is less than 90°C, the base material 41 may be completely melted during heat curing. On the other hand, if the melting point of the base material 41 exceeds 180°C, the arithmetic average roughness of the back surface of the base material 41 may not change even after heating at 130°C for 2 hours. In addition, the aforementioned melting point is measured in accordance with JIS K7121 (ISO3146), and the detailed measurement method is as shown in the test example described later.

The method of adjusting the melting point of the base material 41 is not particularly limited, but it is generally adjusted by the melting point of the resin material mainly used. In addition, the base material 41 can be adjusted to an arbitrary melting point by mixing plural resin materials having different melting points or copolymerizing plural monomers.

The storage elastic modulus of the base material 41 at 130° C. is preferably 1 MPa to 100 MPa, more preferably 2 MPa to 80 MPa, and still more preferably 5 MPa to 50 MPa. By making the base material 41 of 130 The storage elastic modulus at °C is within the aforementioned range, and the arithmetic mean roughness (Ra2) of the back surface of the base material 41 after heating is easily adjusted to the aforementioned range. If the storage elastic modulus of the base material 41 at 130° C. is less than 1 MPa, the base material 41 will be greatly deformed during the heat treatment, and the workpiece may not be able to be maintained. In addition, if the storage elastic modulus of the base material 41 at 130° C. exceeds 100 MPa, there is a possibility that the arithmetic average roughness of the back surface of the base material 41 remains unchanged after heating at 130° C. for 2 hours. In addition, the method for measuring the aforementioned storage elastic modulus is as shown in the test example described later.

The method of adjusting the 130°C storage elastic modulus of the base material 41 is not particularly limited, but it is generally adjusted by the storage elastic modulus of the resin material mainly used. In addition, in general, even if the chemical structure is the same, the storage elastic modulus tends to increase when the molecular weight is high, and the storage elastic modulus tends to increase due to cross-linking or narrow molecular weight distribution (concentrated molecular weight distribution). According to these tendencies, the base material 41 can be adjusted to an arbitrary storage elastic modulus.

When using laser light with a wavelength of 1064nm in invisible laser wafer cutting, etc., the light transmittance of the substrate 41 at a wavelength of 1064nm after heating is preferably 40% or more, more preferably 50% or more, and even more preferably 60% above. By making the light transmittance of the 1064nm wavelength of the substrate 41 within the aforementioned range after the substrate 41 is heated, the invisible laser wafer dicing has excellent work piece separation. In this embodiment, the aforementioned light transmittance can be achieved by setting the arithmetic average thickness (Ra2) of the back surface of the base material 41 after heating within the aforementioned range. Furthermore, the higher the light transmittance of the 1064nm wavelength after the substrate 41 is heated, the better, but the achievable light transmittance is about 99% at the maximum.

In addition, when using laser light with a wavelength of 532nm such as a laser mark for the protective film, the light transmittance at a wavelength of 532nm after the substrate 41 is heated is preferably 40% or more, more preferably 50% or more, and still more preferably 60 %above. By making the light transmittance of the 532 nm wavelength of the substrate 41 within the aforementioned range after heating, the laser printability is excellent. In this embodiment, since the arithmetic average thickness (Ra2) of the back surface of the base material 41 after heating is in the aforementioned range, the aforementioned light transmittance can be achieved. again, After the substrate 41 is heated, the light transmittance at a wavelength of 532 nm is the same as the above, the higher the better, but the maximum achievable light transmittance is about 99%.

Specific examples of the resin film constituting the base material 41 include polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films; polypropylene films, Polyolefin films such as ethylene/propylene copolymer film, polybutene film, polybutadiene film, polymethylpentene film, ethylene/norbornene copolymer film, norbornene resin film; ethylene/vinyl acetate Copolymer films, ethylene/(meth)acrylic acid copolymer films, ethylene/(meth)acrylate copolymer films and other ethylene copolymer films; polyvinyl chloride films, vinyl chloride copolymer films and other polyvinyl chloride films; poly Polyester film such as ethylene terephthalate film and polybutylene terephthalate film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; fluororesin film Wait. In addition, modified membranes such as crosslinked membranes and ionomer membranes can also be used. Furthermore, it may be a laminated film in which plural layers of the aforementioned film are laminated. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms.

In the case of a laminated film, it is preferable to arrange, for example, a film whose arithmetic average thickness changes before and after heating on the back side of the base material 41, and arrange on the adhesive layer 42 side of the base material 41 a heat-resistant and high-temperature non-deformable film. membrane.

Among the foregoing, a polyolefin-based film is preferred, a polyethylene film, a polypropylene film, and an ethylene/propylene copolymer film are more preferred, and an ethylene/propylene copolymer film is still more preferred. These resin films easily satisfy the aforementioned physical properties, and in particular, ethylene/propylene copolymer films can easily satisfy the aforementioned physical properties by adjusting the copolymerization ratio of ethylene monomer and propylene monomer. In addition, these resin films are also preferable from the viewpoints of work adhesion and wafer peelability.

The aforementioned resin film has the purpose of improving its adhesion to the adhesive layer 42 laminated on the surface, and can be subjected to surface treatment by oxidation or embossing method, or primer treatment on one or both sides according to needs. . The foregoing oxidation method may include, for example, corona discharge treatment, plasma discharge treatment, Chromium oxidation treatment (wet type), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, etc., and the unevenness method includes, for example, a sandblasting method, a spray treatment method, and the like.

In addition, the base material 41 may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler in the aforementioned resin film.

The thickness of the base material 41 is not particularly limited as long as it has appropriate functions in each step using the protective film forming composite sheet 3, but it is preferably 20 μm to 450 μm, more preferably 25 μm to 400 μm, and more preferably 50 μm to 350μm.

1-2. Adhesive layer

The adhesive layer 42 of the support sheet 4 of the composite sheet 3 for forming a protective film of this embodiment may be composed of a non-energy-ray curable adhesive or may be composed of an energy-ray curable adhesive. The non-energy-ray-curable adhesive preferably has the required adhesion and releasability. For example, acrylic adhesives, rubber-based adhesives, silicone-based adhesives, urethane-based adhesives, and polyesters can be used. Adhesives, polyvinyl ether adhesives, etc. Among them, an acrylic adhesive that has high adhesion to the protective film forming film 1 and can effectively suppress the peeling of the workpiece or the processed product in the cutting step or the like is preferable.

On the other hand, the energy ray curable adhesive reduces the adhesive force due to energy ray irradiation. Therefore, when separating the workpiece or the processed object from the support sheet 4, it can be easily separated by irradiating energy ray.

When the adhesive layer 42 is formed from an energy-ray curable adhesive, it is preferable to harden the adhesive layer 42 in the composite sheet 3 for forming a protective film. The material formed by the hardening of the energy-ray curable adhesive usually has a high elastic modulus and a high surface smoothness. Therefore, if the protective film forming film 1 contacting the hardened part made of the aforementioned material is hardened to form a protective film, the protective film is The surface in contact with the hardened portion has high smoothness (gloss) and excellent aesthetics as a wafer protective film. In addition, if laser printing is performed on a protective film with high surface smoothness, the visibility of printing can be improved.

The energy-ray-curable adhesive that constitutes the adhesive layer 42 may be one with energy-ray-curable polymer as the main component, or it may be composed of a non-energy-ray-curable polymer and an energy-ray-curable polyfunctional monomer and/or oligomer. A mixture of polymers as the main component.

The following describes the case where the energy ray curable adhesive has an energy ray curable polymer as the main component.

The energy-ray-curable polymer is preferably a (meth)acrylate (co)polymer (A) (hereinafter referred to as "energy-ray-curable type" Polymer (A)”). The energy ray-curable polymer (A) is preferably one obtained by reacting a (meth)acrylic copolymer (a1) with an unsaturated group-containing compound (a2), and the (meth)acrylic copolymer (a1) ) Has a functional group-containing monomer unit, and the aforementioned unsaturated group-containing compound (a2) has a substituent bonded to the aforementioned functional group.

The acrylic copolymer (a1) is composed of a structural unit derived from a monomer containing a functional group and a structural unit derived from a (meth)acrylate monomer or a derivative thereof.

The functional group-containing monomer as a structural unit of the acrylic copolymer (a1) is preferably a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, an amino group, a substituted amino group, and an epoxy group in the molecule.

Specific examples of the aforementioned functional group-containing monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth) 4-hydroxybutyl acrylate and the like can be used alone or in combination of two or more kinds.

The (meth)acrylate monomer constituting the acrylic copolymer (a1) uses alkyl (meth)acrylate, cycloalkyl (meth)acrylate, and (meth) Benzyl acrylate. Among them, alkyl (meth)acrylates having an alkyl group of 1 to 18 carbon atoms are preferred. For example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, N-Butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.

In the acrylic copolymer (a1), relative to the total mass of the acrylic copolymer (a1), the content of the structural unit derived from the functional group-containing monomer is usually 3% by mass to 100% by mass, preferably 4% to 80% by mass, more preferably 5% to 40% by mass, relative to the total mass of the acrylic copolymer (a1), derived from the constituent units of the (meth)acrylate monomer or its derivative The content ratio is usually 0% by mass to 97% by mass, preferably 60% by mass to 95% by mass.

Acrylic copolymer (a1) can be obtained by copolymerizing the aforementioned functional group-containing monomers with (meth)acrylate monomers or their derivatives by conventional methods, but in addition to these monomers, it is also possible to Copolymerization of dimethyl acrylamide, vinyl formate, vinyl acetate, styrene, etc.

The acrylic copolymer (a1) having the aforementioned functional group-containing monomer unit and the unsaturated group-containing compound (a2) having a substituent bonded to the aforementioned functional group are reacted to obtain energy ray hardening Type polymer (A).

The substituent having the unsaturated group-containing compound (a2) can be appropriately selected according to the type of the functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amino group or a substituted amino group, the substituent is preferably an isocyanate group or an epoxy group, and when the functional group is an epoxy group, the substituent is preferably an amino group, a carboxyl group or an aziridinyl group.

In addition, the energy-beam polymerizable carbon-carbon double bonds contained in the unsaturated group-containing compound (a2) are preferably 1 to 5, and more preferably 1 to 2 per molecule. Specific examples of such an unsaturated group-containing compound (a2) include, for example, 2-methacryloxyethyl isocyanate, isopropylene-α,α-dimethylbenzyl isocyanate, methyl isocyanate Acrylic acid ester, propylene isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; a monomer obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate Acrylic isocyanate compound; Acrylic monoisocyanate compound obtained by reacting diisocyanate compound or polyisocyanate compound and polyol compound with hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (Meth)acrylic acid, (A 2-(1-aziridine) ethyl acrylate, 2-vinyl-2-oxazoline (2-vinyl-2-oxazoline), 2-isopropenyl-2-oxazoline, etc.

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

When the acrylic copolymer (a1) is reacted with the unsaturated group-containing compound (a2), the reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst can be appropriately selected in accordance with the combination of functional groups and substituents. Thereby, the functional group present in the acrylic copolymer (a1) is reacted with the substituent in the unsaturated group-containing compound (a2), and the unsaturated group is introduced into the side chain in the acrylic copolymer (a1), The energy ray hardening polymer (A) is obtained.

The weight average molecular weight of the energy ray curable polymer (A) thus obtained is preferably 10,000 or more, more preferably 150,000 to 1.5 million, and still 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 gel permeation chromatography (GPC method).

When the energy-ray-curable adhesive has an energy-ray-curable polymer as the main component, the energy-ray-curable adhesive may further contain energy-ray-curable monomers and/or oligomers (B).

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

Examples of the aforementioned energy-ray curable monomer and/or oligomer (B) include monofunctional acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; trimethylolpropane Tri(meth)acrylate, neopentaerythritol tri(meth)acrylate, neopentaerythritol tetra(meth)acrylate, dineopentaerythritol hexa(meth)acrylate, 1,4-butane Glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tricyclodecane Multifunctional acrylates such as di(meth)acrylate; polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate, etc.

When blending energy ray curable monomers and/or oligomers (B), relative to the total mass of the energy ray curable adhesive, the energy ray curable monomer and/or energy ray curable adhesive The content of the oligomer (B) is preferably from 5 to 80% by mass, more preferably from 20 to 60% by mass.

Here, when ultraviolet rays are used as the energy ray for curing the energy ray curable resin composition, it is preferable to add a photopolymerization initiator (C). The use of the photopolymerization initiator (C) can reduce polymerization hardening. Time and amount of light exposure.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, Benzoin dimethyl ketal, 2,4-diethylthioxanthen (2,4-diethylthioxanthen), 1-hydroxycyclohexyl phenone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide ( tetramethylthiuram monosulfide), azobisisobutyronitrile, diphenylethylenedione, dibenzyl ether, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligomer {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]acetone}, 2, 2-Dimethoxy-1,2-diphenylethane-1-one, etc. These can be used individually or in combination of 2 or more types.

Relative to 100 mass points of energy-ray-curable copolymer (A) (when energy-ray-curable monomers and/or oligomers (B) are blended, it is energy-ray-curable copolymer (A) and energy-ray-curable The total amount of the monomer and/or oligomer (B) (B) is 100 mass parts), the usage amount of the photopolymerization initiator (C) is preferably 0.1 to 10 mass parts, more preferably 0.5 to 10 mass parts 6 quality points.

In addition to the aforementioned components, other components may be appropriately blended in the energy ray curable adhesive. Examples of other components include non-energy-ray curable polymer components or oligomer components (D), crosslinking agents (E), and the like.

Examples of non-energy-ray curable polymer components or oligomer components (D) include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc. The weight average molecular weight (Mw) is preferred. It is a polymer or oligomer in the range of 3,000 to 2.5 million.

As the crosslinking agent (E), a polyfunctional compound can be used, and the aforementioned polyfunctional compound has reactivity with a functional group contained in the energy ray curable copolymer (A) or the like. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxy compounds, metal chelate compounds, and metal salts. , Ammonium salt, reactive phenol resin, etc.

By blending these other components (D) and (E) into the energy ray curable adhesive, the adhesiveness and peelability of the adhesive layer 42 before curing, the strength after curing, and the adhesion to other layers can be improved Performance, preservation stability, etc. The blending amount of these other components is not particularly limited, and can be appropriately determined in the range of 0 to 40 parts by mass relative to 100 parts by mass of the energy ray curable copolymer (A).

Next, the case where the energy-ray-curable adhesive is mainly composed of a mixture of a non-energy-ray-curable polymer component and an energy-ray-curable polyfunctional monomer and/or oligomer will be described.

For the non-energy-ray curable polymer component, for example, the same components as the aforementioned acrylic copolymer (a1) can be used. Relative to the total mass of the energy ray curable resin composition, the content of the non-energy ray curable polymer component in the energy ray curable resin composition is preferably 20% by mass to 99.9% by mass, more preferably 30% by mass to 80% by mass.

The energy ray-curable polyfunctional monomer and/or oligomer can be selected from the same as the aforementioned component (B). Non-energy-ray-curable polymer components and energy-ray-curable polyfunctional monomers and/or oligomers The blending ratio of the polymer is preferably 10 parts by mass to 150 parts by mass relative to 100 parts by mass of the polymer component of the polyfunctional monomer and/or oligomer, and more preferably 25 parts by mass to 100 parts by mass.

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

When it has an appropriate function in each step of using the composite sheet 3 for forming a protective film, the thickness of the adhesive layer 42 is not specifically limited. Specifically, the thickness of the adhesive layer 42 is preferably 1 μm to 50 μm, more preferably 2 μm to 30 μm, and still more preferably 3 μm to 20 μm.

2. Protective film forming film

The protective film forming film 1 is for forming a protective film on a workpiece or a processed product obtained by processing the aforementioned workpiece. This protective film is composed of a protective film forming film 1, preferably a cured protective film forming film 1. The workpiece may be, for example, a semiconductor wafer, and the processed product obtained by processing the foregoing workpiece may be, for example, a semiconductor wafer, but the present invention is not limited to these. In addition, when the workpiece is a semiconductor wafer, the protective film is formed on the inner surface side of the semiconductor wafer (the side where the bumps and other electrodes are not formed).

The protective film forming film 1 may be composed of a single layer or a plurality of layers, but considering the ease of controlling the light transmittance and the manufacturing cost, it is preferably composed of a single layer.

The protective film forming film 1 is preferably formed of an uncured curable adhesive. In this case, the protective film forming film 1 is hardened after stacking a work such as a semiconductor wafer on the protective film forming film 1, whereby the protective film can be firmly adhered to the work, and a durable protective film can be formed for wafers and the like.

The protective film forming film 1 preferably has adhesiveness at room temperature or exhibits adhesiveness by heating. Thereby, when a work such as a semiconductor wafer is laminated on the protective film forming film 1 described above, the two can be bonded together. Therefore, the position can be surely determined before the film 1 is formed by curing the protective film.

The curable adhesive constituting the protective film forming film 1 having the aforementioned characteristics preferably contains a curable component and a binder polymer component. The hardening component can be made with thermosetting It is a component, an energy ray curable component, or a mixture of these, but it is preferable to use a thermosetting component. That is, the protective film forming film 1 is preferably composed of a thermosetting adhesive.

Examples of thermosetting components include epoxy resins, phenol resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, polyimide resins, benzooxazine resins, etc. And other mixtures. Among them, the thermosetting component preferably uses epoxy resin, phenol resin and a mixture of these.

Epoxy resin has the property of being three-dimensional network after being heated and forming a firm film. Although various known epoxy resins can be used as the aforementioned epoxy resin, it is usually preferably one with a number average molecular weight of about 300 to 2000, and more preferably one with a number average molecular weight of 300 to 500. It is more preferable to mix an epoxy resin having a number average molecular weight of 330 to 400 and a liquid state in normal state with an epoxy resin having a number average molecular weight of 400 to 2500, preferably a number average molecular weight of 500 to 2000, and which is solid at room temperature. Form use. In addition, the epoxy equivalent of the epoxy resin is preferably 50 g/eq to 5000 g/eq. In addition, the number average molecular weight of the epoxy resin can be obtained by the method using GPC.

Specific examples of the aforementioned epoxy resin include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenylnovolac, and cresol novolac; butylene glycol, polyethylene glycol , Glycidyl ether of alcohols such as polypropylene glycol; glycidyl ether of carboxylic acids such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, etc.; bonding the nitrogen atom of aniline isocyanate, etc. Epoxy propyl or alkyl glycidyl type epoxy resin in which the active hydrogen is substituted by glycidyl group; such as diepoxyethylene cyclohexane, 3,4-epoxycyclohexylmethyl-3 ,4-Dicyclohexane carboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, etc., for example When an epoxy group is introduced into the carbon-carbon double bond in the molecule by oxidation, that is, an alicyclic epoxide. In addition, epoxy resins having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, and the like can also be used.

Among them, the epoxy resin is preferably a bisphenol-based glycidyl type epoxy resin, an o-cresol novolak type epoxy resin, and a phenol novolak type epoxy resin. These epoxy resins can be used individually by 1 type or in combination of 2 or more types.

When an epoxy resin is used, it is preferable to use a thermally active latent epoxy resin hardener as an auxiliary agent in combination. Thermally active latent epoxy resin hardener is a type of hardener that does not react with epoxy resin at room temperature, but is activated and reacts with epoxy resin when heated to a certain temperature or higher. The activation method of the thermally active latent epoxy resin hardener includes the following methods: the method of generating active species (anions, cations) by the chemical reaction of heating; stable dispersion in the epoxy resin near room temperature, at high temperature The method of dissolving with epoxy resin, dissolving and starting the hardening reaction; the method of dissolving out at high temperature by containing the hardener of molecular sieve type and starting the hardening reaction; the method of using microcapsules, etc.

Specific examples of thermally active latent epoxy resin hardeners include various onium salts, diprotic acid dihydrazine compounds, dicyandiamine, amine adduct hardeners, imidazole compounds, etc. Active hydrogen compounds, etc. These thermally active latent epoxy resin hardeners can be used individually by 1 type or in combination of 2 or more types. Relative to 100 parts by weight of epoxy resin, the use ratio of the aforementioned thermally active latent epoxy resin hardener is preferably 0.1 parts by weight to 20 parts by weight, more preferably 0.2 parts by weight to 10 parts by weight, and still more preferably 0.3 weight points to 5 weight points.

As the phenol resin, polycondensates of phenols and aldehydes, such as alkylphenols, polyhydric phenols, and naphthols, can be used, and they are not particularly limited. Specifically, for example, phenol novolak resin, ortho-cresol novolak resin, p-cresol novolak resin, tertiary butylphenol novolak resin, dicyclopentadiene cresol resin, poly(p-cresol) Phenolic novolac resins, or their modified products, etc.

By heating, the phenolic hydroxyl group contained in the phenol-based resin can easily undergo an addition reaction with the epoxy group of the aforementioned epoxy resin to form a cured product with high impact resistance. Therefore, an epoxy resin and a phenol resin can be used together as a thermosetting component.

The binder polymer component can impart appropriate viscosity to the protective film forming film 1 and improve the operability of the protective film forming composite sheet 3. The weight average molecular weight of the binder polymer is usually 50,000 to 2 million, preferably 100,000 to 1.5 million, and more preferably 200,000 to 1 million. If the molecular weight is too low, the film formation of the protective film forming film 1 is insufficient, and if it is too high, the compatibility with other components deteriorates, and as a result, the film cannot be uniformly formed. As the binder polymer, for example, acrylic polymer, polyester resin, phenoxy resin, urethane resin, silicone resin, rubber polymer, etc. can be used, and acrylic polymer is preferred.

Examples of the acrylic polymer include (meth)acrylate copolymers composed of structural units derived from (meth)acrylate monomers and (meth)acrylic acid derivatives. Here, the (meth)acrylate monomer is preferably an alkyl (meth)acrylate with an alkyl group of 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, ( Propyl meth)acrylate, butyl (meth)acrylate, etc. In addition, the (meth)acrylic acid derivative includes, for example, (meth)acrylic acid, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

Among the foregoing, if glycidyl methacrylate or the like is used as a structural unit and a glycidyl group is introduced into the acrylic polymer, the compatibility with the epoxy resin as the thermosetting component mentioned above will be improved and the protective film The glass transition temperature (Tg) of the formed film 1 after hardening becomes higher, and the heat resistance is improved. In addition, in the foregoing, if hydroxyethyl acrylate or the like is used as a structural unit and a hydroxyl group is introduced into the acrylic polymer, the adhesion to the workpiece and the adhesive properties can be controlled.

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

The blending ratio of the thermosetting component and the binder polymer component is preferably 50 parts by weight to 1500 parts by weight relative to 100 parts by weight of the binder polymer component, more preferably 70 parts by weight to 1000 parts by weight , And more preferably blended from 80 to 800 parts by weight. By blending the thermosetting component and the binder polymer component in the aforementioned ratio, it can exhibit moderate viscosity before hardening and can perform the sticking operation stably, and after hardening, a protective film with excellent film strength can be obtained.

The protective film forming film 1 preferably contains a colorant and/or a filler, and more preferably contains both a colorant and a filler.

As the coloring agent, known inorganic pigments, organic pigments, organic dyes, etc. can be used, but from the viewpoint of improving light transmittance controllability, the coloring agent preferably contains an organic coloring agent. From the viewpoint of improving the chemical stability of the colorant (specifically, for example, the ease of elution, the ease with which migration occurs, and the degree of change over time), the colorant preferably contains a pigment.

The filler can include, for example, silica such as crystalline silica, fused silica, and synthetic silica; and inorganic fillers such as alumina and glass balls. Among them, the filler is preferably silicon dioxide, more preferably synthetic silicon dioxide, and is most suitable for the type of synthetic silicon dioxide that can effectively remove the line source of the alpha line. The aforementioned alpha line is the cause of the malfunction of the semiconductor device. The main reason. The shape of the filler may include a spherical shape, a needle shape, an amorphous shape, etc., but a spherical shape is preferable, and a true spherical shape is more preferable. If the filler is spherical or true spherical, the light is not easily diffused reflection, and it is easy to control the spectrum of the light transmittance of the protective film forming film 1.

In addition, the protective film forming film 1 may contain a coupling agent. By containing the coupling agent, after the protective film forming film 1 is cured, the adhesion and adhesion between the protective film and the workpiece can be improved without impairing the heat resistance of the protective film, and the water resistance (humid heat resistance) can be improved. Considering its versatility and cost advantages, the coupling agent is preferably a silane coupling agent.

The silane coupling agent includes, for example, γ-glycidoxy propyl trimethoxy silane, γ-glycidoxy propyl methyl diethoxy silane, β-(3,4-epoxycyclohexyl) ethyl trimethyl Oxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethyl Oxysilane, N-6-(aminoethyl)-γ-aminopropylmethyl diethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, γ-ureidopropyl Triethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl) tetrasulfane (bis(3-ethoxysilylpropyl) ) tetrasulfane), methyl trimethoxy silane, methyl triethoxy silane, vinyl trimethoxy silane, vinyl triacetoxy silane, imidazole silane, etc. The silane coupling agent can be used singly or as a mixture of two or more.

In order to adjust the cohesive force before curing, the protective film forming film 1 may contain a cross-linking agent such as an organic polyvalent isocyanate compound, an organic polyvalent imine compound, and an organometallic chelate compound. In addition, in order to suppress static electricity and improve the reliability of the wafer, the protective film forming film 1 may contain an antistatic agent. Furthermore, in order to improve the flame retardancy of the protective film and the reliability of packaging, the protective film forming film 1 may contain flame retardants such as phosphoric acid compounds, bromine compounds, and phosphorus compounds.

In order to effectively function as a protective film, the thickness of the protective film forming film 1 is preferably 3 μm to 300 μm, more preferably 5 μm to 200 μm, and still more preferably 7 μm to 100 μm.

3. Adhesive layer for jig

The adhesive constituting the adhesive layer 5 for jigs preferably has the required adhesiveness and releasability. For example, acrylic adhesives, rubber-based adhesives, silicone-based adhesives, and urethane-based adhesives can be used. Adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among them, the adhesive layer 5 for jigs is preferably an acrylic adhesive. Since it has high adhesion with jigs such as ring frames, it can effectively prevent the composite sheet 3 for forming the protective film from being ringed during the cutting step. The rack is peeled off. In addition, a base material as a core material may be interposed in the thickness direction of the adhesive layer 5 for jigs.

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

4. Peel off sheet

The peeling sheet 6 of this embodiment protects the protective film formation film 1 and the adhesive layer 5 for jigs until the composite sheet 3 for protective film formation is used.

The configuration of the release sheet 6 is arbitrary, and, for example, the plastic film is peeled off 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, for example, silicone-based, fluorine-based, lanthanide-based, etc. can be used, but among these, a silicone-based, which is inexpensive and has stable performance, is preferred. The thickness of the release sheet 6 is not particularly limited, but is usually about 20 μm to 250 μm.

5. Manufacturing method of composite sheet for protective film formation

It is preferable to separately prepare the first laminate containing the protective film forming film 1 and the second laminate containing the support sheet 4, and then use the first laminate and the second laminate to laminate the protective film forming film 1 and the support sheet 4 The composite sheet 3 for forming a protective film can be manufactured by this, but it is not limited to this.

In the manufacture of the first laminate, the protective film forming film 1 is formed on the peeling surface of the first peeling sheet. Specifically, a coating agent for forming a protective film is prepared first. The aforementioned coating agent for forming a protective film contains a curable adhesive that constitutes the protective film forming film 1 and optionally a solvent. Coaters such as coaters, roll knife coaters, air knife coaters, die coaters, bar coaters, gravure coaters, curtain coaters, etc. are applied to the release surface of the first release sheet and dried to form a protective film to form a film 1 . Next, the release surface of the second release sheet was laminated and pressed on the exposed surface of the protective film forming film 1 to obtain a laminate (first laminate) in which the protective film forming film 1 was sandwiched by two release sheets.

In this first laminate, if necessary, a half cut may be applied from the side of the first release sheet or the second release sheet with a cutting blade or laser irradiation to form a protective film into a film 1 (and a second release sheet). The sheet) is formed into a desired shape, such as a circle. At this time, the excess portions of the protective film forming film 1 and the second release sheet generated by the half-cut line can be appropriately removed.

In addition, in the production of the second laminate, the adhesive layer coating agent is applied to the release surface of the third release sheet. The adhesive layer coating agent contains the adhesive constituting the adhesive layer 42 and may further contain The solvent dries to form the adhesive layer 42. After that, the substrate 41 is pressed on the exposed surface of the adhesive layer 42 to obtain a laminate (second laminate) including the support sheet 4 and the third release sheet. The support sheet 4 includes the substrate 41 and the adhesive layer 42 .

Here, when the adhesive layer 42 is formed of an energy-ray curable adhesive, the adhesive layer 42 can be irradiated with energy rays at this stage to harden the adhesive layer 42, or the adhesive layer 42 can be hardened and adhered after being laminated with the protective film to form the film 1剂层42。 Agent layer 42. In addition, when the adhesive layer 42 is hardened after the film 1 is laminated with the protective film, the adhesive layer 42 may be hardened before the cutting step, or the adhesive layer 42 may be hardened after the cutting step.

The energy line usually uses ultraviolet rays, electron beams, etc. The irradiation amount of the energy ray varies with the type of the energy ray. For example, the amount of ultraviolet light is preferably 50 mJ/cm ² to 1000 mJ/cm ² , more preferably 100 mJ/cm ² to 500 mJ/cm ² . In addition, the electron beam is preferably about 10 krad to 1000 krad.

The first laminate and the second laminate are obtained in the above manner, the second release sheet in the first laminate is peeled off, and the third release sheet in the second laminate is peeled off, and then the first laminate is exposed to the protective film The forming film 1 and the adhesive layer 42 of the supporting sheet 4 exposed by the second laminate are laminated and pressed. The support sheet 4 is half-cut as necessary, and can be formed into a desired shape, for example, a circle having a larger diameter than the protective film forming film 1. At this time, the redundant part of the support sheet 4 produced by the half-cut line can be appropriately removed.

In this way, a composite sheet 3 for forming a protective film is obtained, which includes a support sheet 4 formed by laminating an adhesive layer 42 on a substrate 41, a protective film forming film 1 laminated on the adhesive layer 42 side of the support sheet 4, and a laminated layer The first on the side opposite to the support sheet 4 in the protective film forming film 1 Peel off the piece. Finally, after peeling the first release sheet, the adhesive layer 5 for jigs is formed on the edge portion of the protective film forming film 1 on the opposite side to the support sheet 4. The adhesive layer 5 for jigs can be formed by applying the same method as the adhesive layer 42 described above.

6. How to use the composite sheet for forming a protective film

As an example of use of the composite sheet 3 for forming a protective film in this embodiment, a method of manufacturing a wafer with a protective film from a semiconductor wafer as a workpiece will be described below.

First, pull out the protective film forming composite sheet 3 in the form of a winding roll. As shown in FIG. 2, the protective film forming film 1 of the protective film forming composite sheet 3 is attached to the semiconductor wafer 7, and the jig is adhered The agent layer 5 is attached to the ring frame 8.

In the composite sheet 3 for forming a protective film of the present embodiment, by setting the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating to 0.2 μm or more, adhesion is not likely to occur during the aforementioned pulling out, and pulling can be suppressed. The occurrence of defects and the inability to attach to the workpiece.

After that, the protective film forming film 1 is cured to form a protective film to obtain a laminated structure (hereinafter referred to as "laminated structure L"). The aforementioned laminated structure system has a protective film laminated on the adhesive layer 42 side of the support sheet 4 For the semiconductor wafer 7, the aforementioned support sheet 4 has a function as an extensible dicing sheet. The laminated structure L shown in FIG. 2 further has an adhesive layer 5 for jigs and a ring frame 8. When the protective film forming film 1 is a thermosetting adhesive, the protective film forming film 1 can be heated at a specific temperature for an appropriate time. In addition, when the protective film forms the film 1 as a non-thermosetting adhesive, another heat treatment is performed.

The aforementioned heating temperature is 50°C to 200°C, preferably 90°C to 150°C, and the heating time is 0.1 hour to 10 hours, preferably 1 hour to 3 hours. The composite sheet 3 for forming a protective film of the present embodiment can be heat-treated so that the arithmetic mean roughness (Ra2) of the back surface of the base material 41 can be 0.25 μm or less.

The laminated structure L provided with the semiconductor wafer 7 having the protective film is obtained as described above, and then the protective film is irradiated with laser light to penetrate the support sheet 4 as necessary to perform laser printing.

Next, a stealth laser wafer dicing step is performed on the laminated structure L. Specifically, the laminated structure L is set in a laser irradiation device for dividing and processing, and after finding the surface position of the semiconductor wafer 7 covered by the protective film 1, the semiconductor wafer 7 is penetrated through the support sheet 4. The laser light is irradiated to form a modified layer in the semiconductor wafer 7. After that, the support sheet 4 having the function as a dicing sheet is stretched by performing an extension step, and a force is applied to the semiconductor wafer 7 having a protective film (a pulling force in the direction of the main surface). As a result, the semiconductor wafer 7 with a protective film attached to the support sheet 4 is divided, and a wafer with a protective film (a wafer with a protective film) is obtained. Then, the wafer with the protective film is taken out from the support sheet 4 using the take-out device.

In the composite sheet 3 for forming a protective film of the present embodiment, the heated arithmetic average thickness (Ra2) of the back surface of the base material 41 is 0.25 μm or less, and thus has excellent laser light penetration. In the printing step, printing with excellent laser printing and high visibility can be formed. In addition, in the aforementioned invisible laser wafer dicing step, the work piece separation by the invisible laser wafer dicing is excellent.

7. Other embodiments of the composite sheet for forming a protective film

Fig. 3 is a cross-sectional view of a composite sheet for forming a protective film according to another embodiment of the present invention. As shown in FIG. 3, the composition of the composite sheet 3A for forming a protective film of this embodiment has: a support sheet 4 composed of an adhesive layer 42 laminated on one side of a base material 41, and an adhesive on the support sheet 4 The protective film forming film 1 laminated on the side of the layer 42 and the release sheet 6 laminated on the side opposite to the supporting sheet 4 of the protective film forming film 1 are laminated. The protective film forming film 1 of this embodiment is formed so that the surface direction is almost the same as or slightly larger than the workpiece, and is formed so that the surface direction is smaller than the support sheet 4. The adhesive layer 42 of the portion where the protective film is not laminated to form the film 1 can be attached to a jig such as a ring frame.

The material and thickness of each member of the composite sheet 3A for forming a protective film of this embodiment are the same as the material and thickness of each member of the composite sheet 3 for forming a protective film described above. However, when the adhesive layer 42 is formed of an energy-ray-curable adhesive, it is preferable to harden the energy-ray-curable adhesive in the part of the adhesive layer 42 that is in contact with the protective film forming film 1 without causing the energy of other parts to be hardened. The linear hardening adhesive hardens. Thereby, the smoothness (gloss) of the protective film of the hardened protective film forming film 1 can be improved, and high adhesion to jigs such as ring frames can be maintained.

In addition, in the adhesive layer 42 of the support sheet 4 of the protective film forming composite sheet 3A, the edge portion on the opposite side to the base material 41 may be provided with an adhesive for jigs that is the same as the aforementioned protective film forming composite sheet 3 Adhesive layer for jigs with the same layer 5.

In addition, the support sheet 4 of this embodiment may not have the adhesive layer 42 but may be composed of the base material 41 (only). At this time, the surface of the substrate 41 on the side of the protective film forming film 1 is the first surface of the support sheet 4, and the surface of the substrate 41 on the side opposite to the side of the protective film forming film 1 is the second surface of the support sheet 4.

When the support sheet 4 is composed of the base material 41, it is preferable to provide an adhesive layer 5 for jigs as shown in FIG.

The embodiments described above are intended to facilitate the understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the foregoing embodiment includes all design changes and equivalents within the technical scope of the present invention.

For example, in the support sheet 4, there may be other layers between the base material 41 and the adhesive layer 42. In addition, other layers may be layered on the first area of the support sheet 4 composed of the base material 41.

In addition, in the composite sheet for forming a protective film of the present invention, except that the arithmetic average roughness (Ra1) of the back surface of the base material 41 before heating is about 0.51 μm to 0.65 μm, the arithmetic average roughness after heating at 130°C for 2 hours In addition to the degree (Ra2) of about 0.08 to 0.22, the storage elasticity of the base material 41 at 130°C is about 13 MPa to 20 MPa, so that the light transmittance even after heating It is about 73% to 91% at 532nm, and about 77% to 91% at 1064nm, which can make it more excellent in adhesion resistance, laser printability, and cutting and splitting.

(Example)

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

[Example 1]

In Example 1, the composite sheet 3 for forming a protective film as shown in FIGS. 3 and 4 was manufactured in the following view.

(1) Fabrication of the first laminate containing the protective film forming film

The following components were mixed at the following blending ratio (converted as solid content), and diluted with methyl ethyl ketone so that the solid content concentration was 61% by mass, to prepare a coating agent for forming a protective film.

(A) Binder polymer: a copolymer of 10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate (methyl ) 100 mass minutes of acrylic ester copolymer (weight average molecular weight: 800,000, glass transition temperature: -1°C).

(B-1) Bisphenol A type epoxy resin (jER828 manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 184 g/eq to 194 g/eq) 60 mass parts.

(B-2) Bisphenol A type epoxy resin (jER1055 manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 800 g/eq to 900 g/eq) 10 mass parts.

(B-3) Dicyclopentadiene epoxy resin (EPICLON HP-7200HH manufactured by DIC Corporation, epoxy equivalent 255 g/eq to 260 g/eq) 30 mass parts.

(C) Thermally active latent epoxy resin hardener: dicyandiamine (ADEKA HARDENER EH-3636AS manufactured by ADEKA, active hydrogen amount 21 g/eq) 2 parts by mass.

(D) Hardening accelerator: 2-phenyl-4,5-dimethylolimidazole (CUREZOL 2PHZ manufactured by Shikoku Kasei Kogyo Co., Ltd.) 2 parts by mass.

(E) 320 mass parts of silica filler (SC2050MA manufactured by Admatechs, average particle size 0.5 μm).

(F) Coloring agent: soot (#MA650 manufactured by Mitsubishi Chemical Corporation, average particle size 28 nm) 0.6 mass parts.

(G) Silane coupling agent: γ-glycidoxypropyltrimethoxysilyloxy (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd., methoxy equivalent: 12.7 mmol/g, molecular weight: 236.3) 0.4 mass parts.

First, on the peeling surface of the first peeling sheet (SP-PET3811, made by Lindeke), the thickness of the protective film forming film obtained at the end is 25 μm, and the protective film forming film is coated with a knife coater. The coating agent was dried at 120°C for 2 minutes to form a protective film forming film. After that, the release surface of the second release sheet (SP-PET381031 made by Lindeke Co., Ltd.) was superimposed on the protective film to form a film, and the two were bonded together to obtain the first release sheet (the release sheet in Figures 3 and 4). 6) A laminate composed of a protective film forming film (protective film forming film 1 in Figs. 3 and 4) and a second release sheet. This laminated system is a long strip, and it is rolled into a roll to become a roll.

Long will the laminate obtained was cut in the winding direction 300mm width (w ₁ shown in FIG. 4). Next, for the laminate, a second release sheet and a protective film were cut to form a film, and a circular shape (diameter d ₁ : 220 mm; Fig. 4 The symbol 101) in the half tangent. Then, the second release sheet and the protective film forming film existing on the outer side of the circle formed by the half-cut line are removed. Thereby, a first laminate is obtained. The first laminate system laminates a circular protective film forming film on the release surface of the first release sheet, and laminates a circular second release sheet on the circular protective film forming film. .

(2) Making the second laminate with supporting sheet

The following components (H) and (I) were mixed, diluted with methyl ethyl ketone so that the solid content concentration was 30% by mass, and the coating agent for the adhesive layer was prepared.

(H) Adhesive main agent: (meth)acrylate copolymer (copolymer obtained by copolymerization of 40 mass parts of butyl acrylate, 55 mass parts of 2-ethylhexyl acrylate, and 5 mass parts of 2-hydroxyethyl acrylate , Weight average molecular weight: 600,000) 100 mass points.

(I) Crosslinking agent: Aromatic polyisocyanate compound (Takenate D110N manufactured by Mitsui Chemicals Co., Ltd.) for 10 parts by mass.

Next, the arithmetic average roughness (Ra1) of one side (the back surface of the substrate (the second surface of the support sheet)) before heating and the arithmetic average roughness (Ra2) after heating (130°C, 2 hours), The melting point and the storage modulus of 130°C were adjusted as shown in Table 1 below to produce an ethylene/propylene copolymer film, and corona treatment was applied to the other side of the film, and this was used as a base material. In addition, the arithmetic average roughness (Ra1) before heating can be adjusted by changing the arithmetic surface roughness of the surface of the metal roll wound on the back side of the substrate during film formation of the substrate. In addition, by adjusting the copolymerization ratio of ethylene and propylene of the ethylene/propylene copolymer constituting the base material, the arithmetic average roughness (Ra2) after heating is adjusted.

Prepare a release sheet (SP-PET381031 made by Lindeco) on one side of a PET film with a thickness of 38μm. In a method of 10 μm, the aforementioned adhesive layer coating agent was applied with a knife coater, and dried to form an adhesive layer. After that, the corona-treated surface of the aforementioned base material is superimposed on the adhesive layer and the two are bonded together to obtain a second laminate. The aforementioned second laminate system includes a support sheet (support sheet 4 in Figures 3 and 4) and a release sheet The aforementioned supporting sheet includes a base material (base material 41 in FIG. 3) and an adhesive layer (adhesive agent layer 42 in FIG. 3). The laminate is elongated, which is wound after the winding direction of the web was cut 300mm (w ₁ shown in FIG. 4).

(3) Making a composite sheet for forming a protective film

The circular second release sheet was peeled off from the first laminate obtained in (1) above, and the circular protective film was exposed to form a film. On the other hand, the second laminate obtained from the above (2) peeled off the release sheet, and exposed the adhesive 着剂层。 The agent layer. The first laminate and the second laminate are bonded so that the protective film forming film is in contact with the adhesive layer to obtain a support sheet composed of a base material and an adhesive layer, a protective film forming film, and a first release The third layered body formed by layered layers.

Next, the third layered body is applied with half cuts by cutting the support sheet (the base material and the adhesive layer) from the aforementioned base material side. Specifically, the system shown in Figure 4, is formed over the protective film to form a film circular (diameter d _1: 220mm) of larger concentric circular (diameter d _2: 270mm; symbol 401 in the FIG. 4; round -Shaped supporting piece), and an arc (symbol 402 in FIG. 4) with an interval of 20 mm (shown by w _{2 in FIG. 4) is formed on the outer side of the aforementioned circle.} In addition, two straight lines (code 403 in FIG. 4) parallel to the widthwise ends of the third laminate are formed between two adjacent circles, and the adjacent arcs are connected to the straight lines.

Then, the part between the circular support sheet and the arc and the part sandwiched by the two straight lines are removed, and a composite sheet for forming a protective film as shown in FIGS. 3 and 4 is obtained.

[Example 2 to Example 5 and Comparative Example 1 to Comparative Example 3]

Except that the arithmetic average roughness before heating (Ra1) and the arithmetic average roughness after heating (Ra2), melting point, and storage elastic modulus at 130°C on the back surface of the base material were changed to those shown in Table 1 below, the same as in the examples 1. In the same manner, the composite sheets for forming protective films of Examples 2 to 5 and Comparative Examples 1 to 3 were produced.

[Test Example 1] <Measure the arithmetic mean roughness of the base material>

Using a contact surface roughness meter (SURFTEST SV-3000 manufactured by Mitutoyo), the cut value λc is 0.8mm, the evaluation length Ln is 4mm, and the back surface of the substrate used in the examples and comparative examples is measured according to JIS B0601:2001 before heating The arithmetic average roughness (Ra1: μm) and the arithmetic average roughness after heating (Ra2: μm). The results are shown in Table 1 below.

Here, the arithmetic mean roughness (Ra2) after heating is in the state where the protective film forming composite sheet of the embodiment and the comparative example with the aforementioned base material is fixed on the ring frame, in the oven After heating at 130°C for 2 hours in an atmospheric environment, it was left to stand and the value after cooling to room temperature was measured. During this heat treatment, the measurement surface (the back surface of the substrate) does not touch the inner wall and bottom of the oven.

[Test Example 2] <Measurement of the melting point of the base material>

Using a differential scanning calorimeter (Q2000 manufactured by TA Instruments), the melting peak temperature of the substrates used in the examples and comparative examples was determined in accordance with JIS K7121 (ISO3146). Specifically, the substrate is heated from 23°C to 200°C at 10°C per minute, and a DSC curve is drawn. The melting peak temperature (°C) was obtained from the obtained DSC curve at the time of heating. The results are shown in Table 1 below.

[Test Example 3] <Measure the storage elasticity of the base material>

The 130°C storage elastic modulus of the substrates used in the examples and comparative examples was measured with the following equipment and conditions. The results are shown in Table 1 below.

Measuring device: TA Instruments' brake elastic modulus measuring device "DMA Q800".

Test start temperature: 0℃.

The end temperature of the test: 200℃.

Heating rate: 3°C/min.

Frequency: 11Hz.

Amplitude: 20μm.

[Test Example 4] <Measurement of light transmittance>

The substrates used in the Examples and Comparative Examples were heated at 130°C for 2 hours as shown in Test Example 1, and then measured with an ultraviolet-visible spectrophotometer (UV-3101PC manufactured by Shimadzu Corporation, without integrating sphere). The light transmittance of the material with a wavelength of 200nm to 1200nm, read the measured values at wavelengths of 532nm and 1064nm. The results are shown in Table 1 below.

[Test Example 5] <Evaluation of Adhesion Resistance>

The first release sheet was peeled from the composite sheet for forming a protective film produced in the Examples and Comparative Examples. Using an adhesive device (RAD-2700 F/12 made by Lindeco), the resulting protective film was formed into a composite sheet In a roll-to-roll method, the silicon wafer (outer diameter: 8 inches, thickness: 100μm) and ring frame (made of stainless steel) are pasted at 70°C. At this time, the sticking operation of 10 sheets was continuously performed, and the adhesion resistance was evaluated according to the following criteria. The results are shown in Table 1 below.

A: It can be pasted without any problems (there is no bonding at all).

B: Although it can be pasted, the base material is partly in close contact with the release sheet on the back side of the base material, and when the protective film forming composite sheet is pulled out, part of the release sheet is peeled off by the adhesive layer or the protective film forming film.

C: At least one support sheet is transferred to the release sheet on the back side of the base material, or the composite sheet for forming the protective film cannot be pulled out.

[Test Example 6] <Evaluation of Laser Printability>

The first release sheet was peeled from the composite sheet for forming a protective film produced in the Examples and Comparative Examples. Using a bonding device (RAD-2700 F/12 made by Lindeco), the obtained composite sheet for forming a protective film was bonded to a silicon wafer (outer diameter: 8 inches, thickness: 100 μm) at 70°C and Ring frame (made of stainless steel). Then, it heat-processed at 130 degreeC for 2 hours, heat-hardened the protective film formation film, and formed the protective film.

Next, a printing device (MD-T1000 manufactured by KEYENCE) was used to penetrate the support sheet to irradiate the protective film with laser light having a wavelength of 532 nm, and perform laser printing on the protective film under the following conditions.

Condition 1: Character size: 0.4mm×0.5mm, character interval: 0.3mm, number of characters: 20 characters

Condition 2: Character size: 0.2mm×0.5mm, character interval: 0.3mm, number of characters: 20 characters

The recognizability of the laser-printed characters formed on the protective film through the support sheet (laser-printability) was evaluated according to the following criteria. The results are shown in Table 1 below.

A: You can read all the text of Conditions 1 and 2 smoothly.

B: Although condition 2 has unclear parts, all the text of condition 1 can be read smoothly.

C: Both conditions 1 and 2 have unclear parts.

[Test Example 7] <Evaluation of Cutting and Dividability>

The first release sheet was peeled from the composite sheet for forming a protective film produced in the Examples and Comparative Examples. Use a bonding device (RAD-2700 F/12 manufactured by Lindeco) to bond the obtained composite sheet for forming a protective film to a silicon wafer (outer diameter: 8 inches, thickness: 100 μm) and Ring frame (made of stainless steel). Then, it heat-processed at 130 degreeC for 2 hours, and heat-hardened the protective film formation film, and formed the protective film.

Next, for the obtained silicon wafer with protective film, a laser cutter (DFL7360 made by DISCO) is used to perform the dicing process of the invisible laser wafer dicing. The above-mentioned invisible laser wafer dicing system includes the following steps.

(Step 1) Set the specific position of the laser cutter so that the silicon wafer and the ring frame of the composite sheet for forming the protective film of the embodiment and the comparative example can be irradiated with laser light from the support sheet side (the back side of the base material) .

(Step 2) After detecting the surface position of the silicon wafer covered by the protective film, set the focus position of the laser light of the laser cutter to form a 9mm×9mm chip body on the silicon wafer with the protective film. Along the cutting line, 1064nm laser light from the laser cutter is irradiated from the side of the protective film 10 times to form a modified layer in the silicon wafer.

(Step 3) The silicon wafer with the protective film forming composite sheet and the ring frame are set on the chip divider (DDS2300 manufactured by DISCO), and the pull-down speed is 100mm/sec, and the extension is 10mm.

Through the above steps, at least a part of the silicon wafer in which the modified layer is formed is divided along the predetermined dividing line to obtain a plurality of chips with protective films. Based on the dividing rate at this time (=(the number of wafers actually divided/the number of chips to be divided)×100)(%), the dicing and dividing properties were evaluated based on the following criteria. The results are shown in Table 1.

A: The wafer splitting rate is 100% (excellent splitting).

B: The wafer split rate is 90% or more but less than 100% (with acceptable splitting).

C: The wafer division rate is 80% or more but less than 90% (with acceptable division).

D: The wafer splitting rate is less than 80% (not having acceptable splitting).

It can be seen from Table 1 that the arithmetic average roughness (Ra1) of the back surface of the substrate before heating is 0.2μm or more, and the arithmetic average roughness (Ra2) of the back surface of the substrate is 0.25μm or less after heating at 130°C for 2 hours. The composite sheet for protective film formation is excellent in adhesion resistance, and also excellent in laser printing and cutting and dividing properties.

(Industrial availability)

The composite sheet for forming a protective film of the present invention is suitable for situations including a step of irradiating laser light through a substrate, such as laser printing and invisible laser wafer cutting.

1‧‧‧Protection film forming film

3‧‧‧Composite sheet for forming protective film

4‧‧‧Support film

41‧‧‧Substrate

42‧‧‧Adhesive layer

5‧‧‧Adhesive layer for fixture

6‧‧‧Peeling sheet

Claims (7)

A composite sheet for forming a protective film, which has a support sheet and a protective film forming film laminated on the first surface side of the support sheet; a film composed of a copolymer of ethylene and propylene having a base material; the aforementioned support sheet It includes the substrate and an adhesive layer laminated on the side of one side of the substrate and is the first side of the support sheet; or the support sheet is composed of a substrate; the second surface of the support sheet The arithmetic mean roughness (Ra1) is 0.2μm or more; after heating the support sheet at 130°C for 2 hours, the arithmetic mean roughness (Ra2) of the second surface of the support sheet is 0.25μm or less; the substrate is at 130°C The storage elastic modulus of 1 MPa to 100 MPa; the arithmetic average roughness (Ra2) of the second surface of the support sheet after heating is less than the arithmetic average roughness (Ra1). The composite sheet for forming a protective film according to claim 1, wherein the melting point of the base material is 90°C to 180°C. The composite sheet for forming a protective film according to claim 1 or 2, wherein the substrate has a light transmittance of 40% or more at a wavelength of 1064 nm after the heating. The composite sheet for forming a protective film according to claim 1 or 2, wherein the light transmittance of the base material at a wavelength of 532 nm after the heating is 40% or more. The composite sheet for forming a protective film according to claim 1 or 2, wherein the composite sheet for forming a protective film has an adhesive layer for a jig, and the adhesive layer for a jig is laminated in the protective film forming film and The supporting sheet side is the edge portion on the opposite side. The composite sheet for forming a protective film as described in claim 1 or 2, which has a release sheet, and the release sheet is laminated on the protective film forming film. The composite sheet for forming a protective film as described in claim 1 or 2, wherein the aforementioned protective The film forming film is a layer that forms a protective film on a semiconductor wafer or a semiconductor wafer obtained by dicing a semiconductor wafer.

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