TW201602303A - 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 0.2[mu]m or more and the arithmetic average roughness (Ra2) of the second surface of the supporting film 4 after heating the supporting film 4 at 130 CDE G for two hours is 0.25[mu]m or less.

Description

Composite film for forming a protective film

The present invention relates to a composite sheet for forming a protective film, which is capable of forming a protective film on a workpiece such as a semiconductor wafer or a processed article (for example, a semiconductor wafer) obtained by processing the workpiece.

The present application claims priority based on Japanese Patent Application No. 2014-106757, filed on May 23, 2014, and the content of which is incorporated herein.

In recent years, semiconductor devices have been fabricated by 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 inner surface side of the semiconductor wafer in which the circuit is not formed is exposed is formed.

Therefore, in order to protect the semiconductor wafer, a protective film containing a thermosetting organic material is formed on the inner surface side of the semiconductor wafer. Usually, the protective film is printed on the surface of the semiconductor wafer to indicate the article number or the like. At this time, the printing method generally uses a laser marking method (laser printing) for irradiating the protective film with laser light.

Each of Patent Documents 1 to 3 discloses a protective film forming/cutting integrated sheet (a composite sheet for forming a protective film) in which a protective film forming layer (protective film forming film) capable of forming the protective film is formed on an adhesive sheet. In the protective film forming/cutting integrated sheet, the protective film forming film is cured by heat treatment to form the protective film. In other words, the semiconductor wafer can be diced by the protective film forming/cutting integrated sheet, and a protective film for the semiconductor wafer can be formed to obtain a semiconductor wafer with a protective film.

In addition, when a workpiece including a sheet of a semiconductor wafer or the like is produced from a workpiece such as a semiconductor wafer, a workpiece for which a workpiece is sprayed for cleaning or the like is generally used, and the workpiece is cut by a rotary blade to obtain a sheet. Tool cutting processing. However, in recent years, invisible laser wafer cutting (STEALTH DICING (registered trademark); the same below) which can be dry-divided into sheets has been used (patent document 3).

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

(previous technical literature)

(Patent Literature)

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

Patent Document 2: JP-A-2012-33637

Patent Document 3: JP-A-2011-151362

Patent Document 4: Japanese Patent No. 3762409

Patent Document 5: JP-A-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 needs to have laser light transmittance.

Further, in order to protect the protective film forming film, the release sheet is often laminated on the opposite side of the adhesive sheet of the protective film forming film in the composite sheet for forming a protective film. When the composite sheet for forming a protective film is pulled out from the roll state, the surface on the opposite side of the protective film forming film of the wound adhesive sheet and the surface on the opposite side of the protective film forming film of the release sheet are adhered to each other to cause adhesion ( Blocking) causes a defect that is pulled out by the roller, or the adhesive sheet is transferred to the wound release sheet and cannot be attached to the workpiece.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a composite sheet for forming a protective film, which is capable of suppressing adhesion when a composite sheet for forming a protective film is pulled out in a state of being wound into a roll, and when irradiating laser light. Laser light wear Excellent permeability.

In order to achieve the above object, a first aspect of the present invention provides a composite sheet for forming a protective film (Invention 1), comprising a support sheet and a protective film forming film laminated on the first surface side of the support sheet, the support sheet The arithmetic mean roughness (Ra1) of the second surface is 0.2 μm or more, and after the support sheet is heated at 130 ° C for 2 hours, the arithmetic mean roughness (Ra2) of the second surface of the support sheet is 0.25 μm or less. Further, in the present specification, the "slice" includes the concept of, for example, a long strip.

According to the 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, a protective film forming film is provided) When the release sheet is a release sheet, when the release sheet is not provided, it is a protective film formation film or the like, and it is difficult to adhere to each other, and when the composite sheet for forming a protective film is pulled out from the wound roll, adhesion is less likely to occur. Further, when the laser light is irradiated from the second surface side of the support sheet, the laser light is not scattered by the unevenness of the second surface of the support sheet and penetrates the support sheet, so that the protection film can be efficiently formed to be cured. Films or workpieces (semiconductor wafers) have excellent laser light penetration.

In the above invention (Invention 1), it is preferable that the arithmetic mean roughness (Ra2) after the heating of the second surface of the support sheet is smaller than the arithmetic mean roughness (Ra1) (Invention 2).

In the above invention (Inventions 1 and 2), it is preferable that the support sheet includes a base material and an adhesive layer which is one side of the base material and is laminated on the first surface side of the support sheet; or the support The film system includes a substrate (Invention 3).

In the above invention (Invention 3), it is preferred that the base material has a melting point of 90 to 180 ° C (Invention 4).

In the above invention (Inventions 3 and 4), it is preferred that the substrate has a storage modulus at 130 ° C of 1 to 100 MPa (Invention 5).

In the above invention (Inventions 3 to 5), it is preferred that the substrate has a light transmittance of 40% or more at a wavelength of 1064 nm after the heating (Invention 6).

In the above invention (Inventions 3 to 6), it is preferred that the substrate has a light transmittance of 40% or more at a wavelength of 532 nm after the heating (Invention 7).

In the above invention (Inventions 3 to 7), the substrate is preferably a film composed of a copolymer of ethylene and propylene (Invention 8).

In the above-mentioned invention (Inventions 1 to 8), it is preferable that the composite sheet for forming a protective film has an adhesive layer for a jig, and the adhesive layer for the jig is laminated on the side opposite to the side of the support sheet in the protective film forming film. Edge portion (Invention 9).

In the above invention (Inventions 1 to 9), it is preferable to have a release sheet, and the release sheet is laminated on the protective film formation film (Invention 10).

In the above invention (Inventions 1 to 10), it is preferable that the protective film forming film is a layer formed on a semiconductor wafer or a semiconductor wafer obtained by cutting a semiconductor wafer to form a protective film (Invention 11).

The composite sheet for forming a protective film of the present invention can suppress the adhesion generated when the composite sheet for forming a protective film is pulled out from the state of the wound roll, and has excellent laser light transmittance when irradiated with laser light.

1‧‧‧Protective film forming film

101‧‧‧round

3, 3A‧‧‧Composite film for protective film formation

4‧‧‧Support tablets

41‧‧‧Substrate

42‧‧‧Adhesive layer

401‧‧‧round

402‧‧‧Arc

403‧‧‧ Straight line

5‧‧‧Adhesive adhesive layer

6‧‧‧ peeling film

7‧‧‧Semiconductor wafer

8‧‧‧Ring frame

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

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

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

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

Embodiments of the present invention will be described below.

Fig. 1 is a cross-sectional view showing a composite sheet for forming a protective film according to an embodiment of the present invention. As shown in Fig. 1, the composite film 3 for forming a protective film of the present embodiment has a support sheet 4 and a protective film forming film 1 which is laminated on one side of the support sheet 4 ("first surface" to be described later". The upper side of FIG. 1 and the adhesive layer 5 for the jig are 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 a jig is used to laminate the composite sheet 3 for forming a protective film to a layer of a jig such as a ring frame. Moreover, the composite sheet 3 for forming a protective film of the present embodiment has the release sheet 6 on the protective film forming film 1 and the adhesive layer 5 for the jig (on the side opposite to the supporting sheet 4). This release sheet 6 is peeled off when the composite sheet 3 for forming a protective film is used, and is not an essential component in the composite sheet 3 for forming a protective film.

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

For example, the composite sheet 3 for forming a protective film according to the present embodiment is for holding a semiconductor wafer while cutting 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. The support sheet 4 of the composite sheet 3 for protective film formation at this time is generally called a dicing sheet.

The composite sheet 3 for forming a protective film of the present embodiment is usually wound into a long roll shape and used in a roll-to-roll manner.

Support piece

The support sheet 4 of the composite sheet 3 for forming a protective film of the present embodiment has a base material 41 and an adhesive layer 42 which is laminated on the surface side of the substrate 41 (the protective film forming film 1 side; Fig. 1) The upper side) In the present specification, the surface on the side of the protective film forming film 1 in the support sheet 4 is the "first surface", and the surface on the opposite side (the lower surface in FIG. 1) is 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 substrate 41 opposite to the adhesive layer 42 (hereinafter referred to as "the back surface of the substrate 41". The back surface of the substrate 41 is the second surface of the support sheet 4) has an arithmetic mean roughness (Ra1) of 0.2. More than μm. After the substrate 41 was heated at 130 ° C for 2 hours and then cooled to room temperature (hereinafter referred to as "after heating"), the arithmetic mean roughness (Ra 2 ) of the back surface of the substrate 41 was 0.25 μm or less. Moreover, the arithmetic mean roughness (Ra1) of the back surface of the base material 41 is the arithmetic mean roughness of the back surface of the base material 41 before heating at 130 ° C for 2 hours, and is hereinafter referred to as "arithmetic average roughness (Ra1) before heating" . The arithmetic mean roughness (Ra1) before heating and the arithmetic mean roughness (Ra2) after heating are measured in accordance with JIS B0601:2001, and the detailed measurement method is as shown in the test example described later.

In addition, the conditions of the heat treatment (130 ° C, 2 hours) are usually heat treatment conditions for thermally curing the protective film forming film 1 , and heating is performed when the wound roll-shaped protective film forming composite sheet 3 is pulled out. In the past, it is heated when irradiated with laser light for laser printing or stealth laser wafer cutting. However, the heat 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 heat treatment may be performed.

When the arithmetic mean roughness (Ra1) before heating of the back surface of the base material 41 is 0.2 μm or more, the back surface of the base material 41 and the surface opposite to the protective film forming film 1 in the release sheet 6 in the wound state are obtained. The two are not easy to connect. Thereby, adhesion is hard to occur when the wound roll-form protective film formation composite sheet 3 is pulled out. Therefore, it is possible to suppress the pull-out failure caused by the adhesion, or to suppress the case where the support sheet 4 is transferred to the wound release sheet 6 and cannot be attached to the workpiece.

From the above viewpoint, the arithmetic mean roughness (Ra1) before heating on the back surface of the substrate 41 is preferably 0.25 μm or more, and more preferably 0.30 μm or more.

Here, the upper limit of the arithmetic mean roughness (Ra1) before heating of the back surface of the substrate 41 is preferably 1.0 μm or less, more preferably 0.8 μm or less, still more preferably 0.7 μm or less. When the arithmetic mean roughness (Ra1) before heating exceeds 1.0 μm, it is difficult to achieve the above-described arithmetic mean roughness (Ra2) after heating.

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

Further, by subjecting the back surface of the substrate 41 to the above-described conditions, the arithmetic mean roughness (Ra2) after heating is 0.25 μm or less, when the laser light is irradiated from the back side of the substrate 41, the laser light is not caused by the substrate. The unevenness on the back surface of the 41 surface is scattered and penetrates the support sheet 4, and the protective film or the workpiece (semiconductor wafer) formed by curing the protective film forming film 1 can be efficiently obtained, and has excellent laser light transmittance. Therefore, in addition to the excellent laser printing performance and the ability to form highly recognizable prints, the workpiece segmentation of the invisible laser wafer is also excellent.

From the above viewpoint, the arithmetic mean roughness (Ra2) after heating of the back surface of the substrate 41 is preferably 0.20 μm or less, more preferably 0.10 μm or less.

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

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

Further, in the base material 41, the arithmetic mean roughness (Ra2) after heating obtained on the back surface of the base material 41 under the above conditions is preferably smaller than the arithmetic mean roughness (Ra1) before heating. By setting in this way, both the adhesion suppression effect before heating and the laser light penetration after heating can be excellent.

The method of adjusting the arithmetic mean roughness (Ra1) before heating on the back surface of the substrate 41 is not particularly limited, but generally, the surface roughness and blasting of the roller used in film formation by changing the resin film constituting the substrate 41 can be changed. It is adjusted by processing, or by heating and melting, and blending a flattened filler.

Further, in the method of adjusting the arithmetic mean roughness (Ra2) after heating on the back surface of the substrate 41, it is preferable that the substrate 41 is composed of a resin film (a film mainly composed of a resin material) having a melting point within a specific range. More preferably, it is composed of a resin film having a melting point within a specific range and a storage modulus of 130 ° C in a specific range.

The melting point of the substrate 41 is preferably from 90 to 180 ° C, more preferably from 100 to 160 ° C, still more preferably from 110 to 150 ° C. By setting the melting point of the base material 41 within the above range, the arithmetic mean roughness (Ra2) after heating of the back surface of the base material 41 is easily adjusted to the above range. When the melting point of the base material 41 is less than 90 ° C, the base material 41 is completely melted during heat curing. On the other hand, when the melting point of the base material 41 exceeds 180 ° C, the arithmetic mean roughness of the back surface of the base material 41 does not change after heating at 130 ° C for 2 hours. Further, the melting point is measured in accordance with JIS K7121 (ISO3146), and the detailed measurement method is as shown in the test examples described later.

The method of adjusting the melting point of the substrate 41 is not particularly limited, but is generally adjusted by the melting point of the resin material mainly used. Also, by mixing the melting point The substrate 41 can be adjusted to any melting point by different plural resin materials or by copolymerizing a plurality of monomers.

The storage elastic modulus of the substrate 41 at 130 ° C is preferably from 1 to 100 MPa, more preferably from 2 to 80 MPa, still more preferably from 5 to 50 MPa. By setting the storage elastic modulus of the base material 41 at 130 ° C to the above range, the arithmetic mean roughness (Ra 2 ) after heating of the back surface of the base material 41 is easily adjusted to the above range. When the storage elastic modulus at 130 ° C of the base material 41 is less than 1 MPa, the base material 41 is largely deformed during the heat treatment, and the workpiece cannot be maintained. Further, when the storage elastic modulus of the substrate 41 at 130 ° C exceeds 100 MPa, there is no change in the arithmetic mean roughness of the back surface of the substrate 41 after heating at 130 ° C for 2 hours. Moreover, the measuring method of the storage elastic modulus is as shown in the test example mentioned later.

The method of adjusting the storage modulus of the substrate 41 at 130 ° C is not particularly limited, but is generally adjusted by the storage modulus of the resin material mainly used. Further, in general, even if the chemical structure is the same, the storage modulus tends to be high when the molecular weight is high, and the storage modulus tends to be high by cross-linking or narrow molecular weight distribution (concentration of molecular weight distribution). The base material 41 can be adjusted to an arbitrary storage modulus according to these tendency.

When laser light having a wavelength of 1064 nm is used in stealth laser wafer cutting or the like, the light transmittance of the substrate 41 after heating at a wavelength of 1064 nm is preferably 40% or more, more preferably 50% or more, and still more preferably 60%. the above. By making The light transmittance at a wavelength of 1064 nm after heating of the substrate 41 is in the above range, and the workpiece separation of the stealth laser wafer is excellent. In the present embodiment, the light transmittance can be achieved by setting the arithmetic mean roughness (Ra2) after heating of the back surface of the substrate 41 within the above range. Further, the higher the light transmittance of the substrate 10 after heating at a wavelength of 1064 nm, the better, but the achievable light transmittance is at most about 99%.

Further, when laser light having a wavelength of 532 nm such as a laser mark is used for the protective film, the light transmittance at a wavelength of 532 nm after heating of the substrate 41 is preferably 40% or more, more preferably 50% or more, and still more preferably 60. %the above. The light transmittance at a wavelength of 532 nm after heating the substrate 41 is in the above range, and the laser printing property is excellent. In the present embodiment, the light transmittance can be achieved by the arithmetic mean roughness (Ra2) after heating of the back surface of the substrate 41 within the above range. Further, the light transmittance at a wavelength of 532 nm after heating of the substrate 41 is as high as possible, but the achievable light transmittance is at most about 99%.

Specific examples of the resin film constituting the substrate 41 include a polyethylene film such as a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, or a high density polyethylene (HDPE) film; a polypropylene film; a polyolefin film such as an ethylene/propylene copolymer film, a polybutene film, a polybutadiene film, a polymethylpentene film, an ethylene/norbornene copolymer film, a norbornene resin film; ethylene/vinyl acetate Vinyl copolymer film, ethylene/(meth)acrylic copolymer film, vinyl copolymer film such as ethylene/(meth)acrylate copolymer film; polyvinyl chloride film, vinyl chloride Polyvinyl chloride film such as copolymer film; polyester film such as polyethylene terephthalate film or polybutylene terephthalate film; polyurethane film; polyimine film; polyphenylene A vinyl film; a polycarbonate film; a fluororesin film or the like. Further, a modified film such as a crosslinked film or an ionic polymer film may be used. Further, a laminated film in which a plurality of layers are laminated may be used for the film. Moreover, "(meth)acrylic acid" as used herein means both acrylic acid and methacrylic acid. Other similar terms are the same.

In the case of the laminated film, for example, a film having a change in arithmetic mean thickness before and after heating is disposed on the back side of the substrate 41, and heat resistance is applied to the adhesive layer 42 side of the substrate 41, and the high temperature is not deformed. membrane.

Among the foregoing, a polyolefin film is preferable, and a polyethylene film, a polypropylene film, and an ethylene/propylene copolymer film are more preferable, and an ethylene/propylene copolymer film is more preferable. These resin films are easy to satisfy the above physical properties, and in particular, the ethylene/propylene copolymer film can easily satisfy the above physical properties by adjusting the copolymerization ratio of the ethylene monomer to the propylene monomer. Moreover, these resin films are also preferable from the viewpoint of workability and wafer peelability.

In order to enhance the adhesion between the resin film and the adhesive layer 42 laminated on the surface, the resin film may be subjected to surface treatment such as oxidation or embossing or undercoating on one or both sides as needed. . Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), fire treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. Further, the embossing method may, for example, be a sand blast method or a spray treatment method.

Further, 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 resin film.

The thickness of the substrate 41 is not particularly limited as long as it has an appropriate function in each step of using the composite sheet 3 for forming a protective film, but is preferably 20 to 450 μm, more preferably 25 to 400 μm, still more preferably 50 to 50. 350μm.

1-2. Adhesive layer

The adhesive layer 42 of the support sheet 4 of the composite sheet for forming a protective film of the present embodiment may be composed of a non-energy line curable adhesive, or may be composed of an energy ray-curable adhesive. The non-energy line curable adhesive preferably has the desired adhesive strength and removability. For example, an acrylic adhesive, a rubber adhesive, an anthrone adhesive, an urethane adhesive, or a polyester can be used. Adhesive, polyvinyl ether adhesive, etc. Among these, an acrylic adhesive which is highly adhesive to the protective film forming film 1 and which can effectively suppress the fall of a workpiece or a workpiece in a cutting step or the like is preferable.

On the other hand, since the energy ray-curable adhesive lowers the adhesive force by the irradiation of the energy ray, it is possible to easily separate the workpiece or the workpiece from the support sheet 4 by irradiating the energy ray.

When the adhesive layer 42 is formed of an energy ray-curable adhesive, it is preferably The adhesive layer 42 in the composite sheet 3 for protective film formation is cured. The material formed by the curing of the energy ray-curable adhesive generally has a high modulus of elasticity and a high surface smoothness. Therefore, when the protective film forming film 1 which is in contact with the hardened portion composed of the above material is cured to form a protective film, the protective film is formed. The surface which is in contact with the hardened portion has high surface smoothness (gloss) and is excellent in appearance as a wafer protective film. Further, if the protective film having a high surface smoothness is subjected to laser printing, the print visibility can be improved.

The energy ray-curable adhesive constituting the adhesive layer 42 may be an energy ray-curable polymer as a main component, or may be a non-energy ray-curable polymer and an energy ray-curable polyfunctional monomer and/or oligo. A mixture of polymers is used as a main component.

Hereinafter, the case where the energy ray-curable adhesive has an energy ray-curable polymer as a main component will be described.

The energy ray-curable polymer is preferably a (meth) acrylate (co)polymer (A) in which an energy ray-curable functional group (energy ray-curable group) is introduced into a side chain (hereinafter referred to as "energy ray hardening 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). A monomer unit having a functional group, and the unsaturated group-containing compound (a2) has a substituent bonded to the above functional group.

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

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

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

The (meth) acrylate monomer constituting the acrylic copolymer (a1) is an alkyl (meth)acrylate, a cycloalkyl (meth)acrylate, or a (meth) group having an alkyl group having 1 to 20 carbon atoms. Benzyl acrylate. Among these, an alkyl (meth)acrylate having an alkyl group having 1 to 18 carbon atoms is preferred, and for example, methyl (meth)acrylate, ethyl (meth)acrylate, or propyl (meth)acrylate may be used. N-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like.

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

The acrylic copolymer (a1) is obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylate monomer or a derivative thereof by a usual method, but in addition to the monomers, Copolymerization of dimethyl methacrylate, vinyl formate, vinyl acetate, styrene, and the like.

The acrylic copolymer (a1) having the above-mentioned functional group-containing monomer unit and the unsaturated group-containing compound (a2) having a substituent bonded to the above functional group are reacted, whereby energy ray hardening is obtained. Type polymer (A).

The substituent having 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 of the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amine group or a substituted amine 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 amine group, a carboxyl group or an aziridine group.

Further, the energy-polymerizable carbon-carbon double bond contained in the unsaturated group-containing compound (a2) is preferably from 1 to 5, more preferably from 1 to 2, per molecule. Specific examples of the unsaturated group-containing compound (a2) include, for example, 2-methylpropenyloxyethyl isocyanate, iso-isopropene-α, α-dimethyl Benzyl ester, methacrylic acid isocyanate, propylene isocyanate, 1,1-(bispropenyloxymethyl)ethyl isocyanate; diisocyanate compound or polyisocyanate compound and (meth)acrylic acid a propylene oxime monoisocyanate compound obtained by reacting hydroxyethyl ester; a propylene oxime monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth) acrylate; ) Glycidyl acrylate; (meth)acrylic acid, 2-(1-aziridine)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2 - isopropenyl-2-oxazoline or the like.

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

When the acrylic copolymer (a1) is reacted with the unsaturated group-containing compound (a2), the reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and a catalyst type can be appropriately selected depending on the combination of the functional group and the substituent. Thereby, the functional group present in the acrylic copolymer (a1) is reacted with a 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 line hardening type 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 from 150,000 to 1,500,000, still more preferably from 200,000 to 1,000,000. In addition, the weight average molecular weight (Mw) of this specification is a polystyrene conversion value measured by gel permeation chromatography (GPC method).

When the energy ray-curable adhesive contains the energy ray-curable polymer as a main component, 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 polyhydric alcohol and a (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 isodecyl (meth)acrylate; and trimethylolpropane; Tris (meth) acrylate, neopentyl alcohol tri (meth) acrylate, neopentyl alcohol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butyl Diol (meth) acrylate, 1,6-hexanediol di(meth) acrylate, polyethylene glycol di(meth) acrylate, dimethylol tricyclodecane di(methyl) Polyfunctional acrylates such as acrylate; polyester oligo (meth) acrylate, polyurethane oligo (meth) acrylate, and the like.

When the energy ray-curable monomer and/or oligomer (B) is blended, the energy ray-hardenable monomer and/or the energy ray-curable adhesive are combined with respect to the total mass of the 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, ultraviolet rays are used as the energy ray-curable resin. When the energy line of the object is hardened, it is preferred to add a photopolymerization initiator (C), and the polymerization hardening time and the amount of light irradiation can be reduced by using the photopolymerization initiator (C).

Specific examples of the photopolymerization initiator (C) include diphenyl ketone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid methyl ester, Benzoin dimethyl ketal, 2,4-diethylthioxanthen, 1-hydroxycyclohexyl benzophenone, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide ( Tetramethylthiuram monosulfide), azobisisobutyronitrile, diphenylethylenedione, dibenzyl ether, diethyl hydrazine, β-chloropurine, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2, 2-Dimethoxy-1,2-diphenylethane-1-one and the like. These may be used alone or in combination of two or more.

100 parts by mass of the energy ray-curable copolymer (A) (when the energy ray-curable monomer and/or oligomer (B) is blended, the energy ray-curable copolymer (A) and the energy ray hardening The photopolymerization initiator (C) is preferably used in an amount of 0.1 to 10 parts by mass, more preferably 0.5 to 6 parts by mass, based on 100 parts by mass of the monomer and/or oligomer (B).

In addition to the above components, the energy ray-curable adhesive may be appropriately blended with other components. Non-energy line hardening polymerization Component or oligomer component (D), crosslinking agent (E), and the like.

The non-energy-curable polymer component or the oligomer component (D) may, for example, be a polyacrylate, a polyester, a polyurethane, a polycarbonate, a polyolefin or the like, and preferably has a weight average molecular weight (Mw). It is a polymer or oligomer of 3,000 to 2.5 million.

A polyfunctional compound can be used as the crosslinking agent (E), and the polyfunctional compound has reactivity with a functional group contained in the energy ray-curable copolymer (A) or the like. Examples of such a polyfunctional compound include an isocyanate compound, an epoxy compound, an amine compound, a melamine compound, an aziridine compound, a hydrazine compound, an aldehyde compound, an oxazoline compound, a metal alkoxide compound, a metal chelate compound, and a metal salt. , ammonium salt, reactive phenol resin, and the like.

By blending the other components (D) and (E) with the energy ray-curable adhesive, the adhesiveness and peeling property of the adhesive layer 42 before curing, the strength after hardening, and the subsequent layers can be improved. Sex, preservation stability, etc. The blending amount of the other components is not particularly limited, and can be appropriately determined within a range of from 0 to 40 parts by mass based on 100 parts by mass of the energy ray-curable copolymer (A).

Next, the energy ray-curable adhesive is a case where a mixture of a non-energy-curable polymer component and an energy ray-curable polyfunctional monomer and/or an oligomer is used as a main component.

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

The energy ray-curable polyfunctional monomer and/or oligomer may be the same as the above component (B). The blend ratio of the non-energy-curable polymer component to the energy ray-curable polyfunctional monomer and/or oligomer is preferably 100 parts by mass of the polyfunctional monomer and/or oligomer relative to the polymer component. 10 to 150 mass points, more preferably 25 to 100 mass points.

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

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

2. Protective film forming film

The protective film forming film 1 is a person who forms a protective film for a workpiece obtained by processing a workpiece or a workpiece. This protective film is formed of a protective film 1 Preferably, it is comprised by the cured protective film formation film 1. The workpiece may be, for example, a semiconductor wafer, and the workpiece obtained by processing the workpiece may be, for example, a semiconductor wafer. However, the present invention is not limited thereto. Further, when the workpiece is a semiconductor wafer, the protective film is formed on the inner surface side of the semiconductor wafer (on the side where no electrode such as a bump is formed).

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

The protective film forming film 1 is preferably formed of an uncured hardenable adhesive. At this time, after the protective film forming film 1 is laminated with a workpiece such as a semiconductor wafer, the protective film forming film 1 is cured, whereby the protective film can be firmly adhered to the workpiece, and a durable protective film can be formed on the wafer or the like.

The protective film forming film 1 preferably has adhesiveness at normal temperature or adhesiveness by heating. Thereby, when the workpiece of the semiconductor wafer or the like is laminated as 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 cured.

The curable adhesive which constitutes the protective film forming film 1 having the above characteristics preferably contains a curable component and a binder polymer component. As the curable component, a thermosetting component, an energy ray curable component or a mixture thereof can be used, but a thermosetting component is preferably used. That is, the protective film forming film 1 It is preferably composed of a thermosetting adhesive.

Examples of the thermosetting component include an epoxy resin, a phenol resin, a melamine resin, a urea resin, a polyester resin, a urethane resin, an acrylic resin, a polyimide resin, a benzooxazine resin, and the like. a mixture of such. Among them, the thermosetting component is preferably an epoxy resin, a phenol resin, and a mixture thereof.

The epoxy resin has a property of being three-dimensionally reticulated after being heated and forming a strong film. Although various known epoxy resins can be used as the epoxy resin, it is usually preferred that the number average molecular weight is about 300 to 2,000, and more preferably the number average molecular weight is from 300 to 500. More preferably, the epoxy resin having a number average molecular weight of 330 to 400 and a normal state is mixed with an epoxy resin having a number average molecular weight of 400 to 2,500, preferably a number average molecular weight of 500 to 2,000 and a solid temperature at room temperature. Form use. Further, the epoxy resin preferably has an epoxy equivalent of from 50 to 5,000 g/eq. Further, the number average molecular weight of the epoxy resin can be determined by a method using GPC.

Specific examples of the epoxy resin include phenolic glycidyl ethers such as bisphenol A, bisphenol F, resorcin, phenylnovolac, and cresol novolac; butylene glycol and polyethylene glycol; a glycidyl ether of an alcohol such as polypropylene glycol; a glycidyl ether of a carboxylic acid such as phthalic acid, isophthalic acid or tetrahydrophthalic acid; and a nitrogen atom such as an aniline trimeric isocyanate Epoxypropyl or alkyl epoxide Base type epoxy resin; such as dicyclohexene oxide cyclohexane, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, and 2-(3,4-epoxy group) a cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane or the like which is introduced into an epoxy group, for example, a lipid, by a carbon-carbon double bond in the molecule by oxidation. Cyclic epoxide. Further, an epoxy resin having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton or the like can also be used.

Among these, the epoxy resin is preferably a bisphenol epoxy propylene epoxy resin, an o-cresol novolak epoxy resin, and a phenol novolak epoxy resin. These epoxy resins may be used alone or in combination of two or more.

When an epoxy resin is used, it is preferred to use a thermally active latent epoxy resin hardener as an auxiliary agent. The heat-activatable latent epoxy resin hardener is a hardener which does not react with an epoxy resin at room temperature but which is activated by heating to a certain temperature or higher and reacts with an epoxy resin. The method for activating a heat-active latent epoxy resin hardener has the following methods: a method of generating an active species (anion, a cation) by a chemical reaction by heating; and stably dispersing in an epoxy resin at a temperature near a room temperature, at a high temperature A method of dissolving, dissolving, and starting a hardening reaction with an epoxy resin; a method of dissolving at a high temperature and starting a hardening reaction by a hardener containing a molecular sieve type; a method of using a microcapsule, and the like.

Specific examples of the thermally active latent epoxy resin hardener include, for example, various onium salts, diazironic acid diterpene compounds, and dicyanoquinone. A high melting point active hydrogen compound such as an amine, an amine adduct hardener or an imidazole compound. These thermally active latent epoxy resin hardeners may be used alone or in combination of two or more. The use ratio of the above-mentioned thermally active latent epoxy resin hardener is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, still more preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the epoxy resin. Minute.

As the phenol resin, a polycondensate of a phenol such as an alkylphenol, a polyhydric phenol or a naphthol and an aldehyde can be used, and it is not particularly limited. Specifically, for example, a phenol novolak resin, an o-cresol novolak resin, a p-cresol novolak resin, a third butyl phenol novolak resin, a dicyclopentadiene cresol resin, a poly-p-phenol resin, a double can be used. a phenol type A novolak resin, or the like, or the like.

The phenolic hydroxyl group contained in the phenol resin can be easily reacted with the epoxy group of the epoxy resin by heating to form a cured product having high punching resistance. Therefore, an epoxy resin and a phenol resin can be used together as a thermosetting component.

The binder polymer component can impart appropriate adhesion to the protective film forming film 1 and improve the workability of the protective film forming composite sheet 3. The weight average molecular weight of the binder polymer is usually from 50,000 to 2,000,000, preferably from 100,000 to 1.5 million, more preferably from 200,000 to 1,000,000. 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, it is compatible with other components. As a result, the film cannot be formed uniformly. As the binder polymer, for example, an acrylic polymer, a polyester resin, a phenoxy resin, a urethane resin, an anthrone resin, a rubber-based polymer or the like can be used, and an acrylic polymer is preferable.

The acrylic polymer may, for example, be a (meth) acrylate copolymer composed of a constituent unit derived from a (meth) acrylate monomer and a (meth) acrylic acid derivative. Here, the (meth) acrylate monomer is preferably an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate or ethyl (meth) acrylate, Methyl) propyl acrylate, butyl (meth) acrylate, and the like. Further, examples of the (meth)acrylic acid derivative include (meth)acrylic acid, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

In the above, when glycidyl methacrylate or the like is used as a constituent unit and the epoxy propyl group is introduced into the acrylic polymer, the compatibility with the epoxy resin as the thermosetting component is improved, and the protective film is provided. The glass transition temperature (Tg) after the film 1 is hardened becomes high, and the heat resistance is improved. In addition, when hydroxyethyl acrylate or the like is used as a constituent unit and a hydroxyl group is introduced into the acrylic polymer, adhesion to the workpiece and adhesive properties can be controlled.

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

The blending ratio of the thermosetting component to the binder polymer component is preferably 50 to 1500 parts by weight, more preferably 70 to 1000 parts by weight, more preferably 100 parts by weight of the thermosetting component of the binder polymer component. It is blended for 80 to 800 parts by weight. By blending the thermosetting component and the binder polymer component in the above ratio, it is possible to exhibit an appropriate viscosity before curing and to perform a bonding operation stably, and to obtain a protective film excellent in film strength after curing.

The protective film forming film 1 preferably contains a coloring agent and/or a filling agent, and more preferably contains both a coloring agent and a filling agent.

A known inorganic pigment, an organic pigment, an organic dye, or the like can be used as the colorant. However, from the viewpoint of improving the light transmittance controllability, the colorant preferably contains an organic colorant. The coloring agent preferably contains a pigment from the viewpoint of improving the chemical stability of the coloring agent (specifically, for example, the ease of elution, the ease of occurrence of the transfer, and the degree of change over time).

Examples of the filler include cerium oxide such as crystalline cerium oxide, molten cerium oxide, and synthetic cerium oxide; and inorganic fillers such as alumina and glass spheres. Among these, the filler is preferably cerium oxide, more preferably synthetic cerium oxide, and is most suitably a synthetic cerium oxide of a type that can effectively remove the line source of the alpha line, which is caused by malfunction of the semiconductor device. Main cause. The shape of the filler may be spherical, needle-shaped, amorphous, etc., but is preferably spherical, and more Jia is really spherical. If the filler is spherical or true spherical, the light is not easily diffused and the spectral spectrum of the light transmittance of the protective film forming film 1 is easily controlled.

Further, the protective film forming film 1 may also contain a coupling agent. By containing the coupling agent, after the protective film forming film 1 is cured, the adhesion and adhesion of the protective film to the workpiece can be improved without impairing the heat resistance of the protective film, and the water resistance (humidity resistance) can be improved. The coupling agent is preferably a decane coupling agent in consideration of its versatility and cost advantage.

The decane coupling agent may, for example, be γ-glycidoxypropyltrimethoxydecane, γ-glycidoxypropyldiethoxydecane, β-(3,4-epoxycyclohexyl)ethyltrimethyl. Oxydecane, γ-(methacryloxypropyl)trimethoxynonane, γ-aminopropyltrimethoxydecane, N-6-(aminoethyl)-γ-aminopropyltrimethyl Oxydecane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxydecane, N-phenyl-γ-aminopropyltrimethoxydecane, γ-ureidopropyl Triethoxy decane, γ-mercaptopropyltrimethoxydecane, γ-mercaptopropylmethyldimethoxydecane, bis(3-triethoxydecylpropyl)tetrasulfane (bis(3-ethoxysilylpropyl) Tetrasulfane), methyltrimethoxydecane, methyltriethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, imidazolium, and the like. The decane coupling agent may be used alone or in combination of two or more.

In order to adjust the cohesive force before hardening, the protective film forming film 1 may contain A crosslinking agent such as a polyisocyanate compound, an organic polyimine compound, or an organometallic chelate compound. Further, in order to suppress static electricity and improve the signal reliability of the wafer, the protective film forming film 1 may contain an antistatic agent. Further, in order to improve the flame retardancy of the protective film and the reliability as a package, the protective film forming film 1 may contain a flame retardant such as a phosphoric acid compound, a bromine compound or a phosphorus compound.

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

3. Fixing adhesive layer

The adhesive constituting the adhesive layer 5 for the jig preferably has the desired adhesive force and re-peelability. For example, an acrylic adhesive, a rubber adhesive, an anthrone adhesive, or an urethane adhesive can be used. Agent, polyester adhesive, polyvinyl ether adhesive, and the like. The adhesive layer 5 for the jig is preferably an acrylic adhesive, and has high adhesion to a jig such as a ring frame, and can effectively suppress the composite film 3 for forming a protective film from being ring-shaped in a dicing step or the like. The rack is peeled off. Further, a base material as a core material may be interposed in the thickness direction of the adhesive layer 5 for a jig.

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

4. Stripping sheet

The release sheet 6 of the present embodiment protects the protective film forming film 1 and the adhesive layer 5 for the jig until the composite sheet 3 for forming a protective film is used.

The structure of the release sheet 6 is arbitrary, and the plastic film is peeled off by a peeling agent etc., for example. 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, an anthrone type, a fluorine type, a long-chain alkane type or the like can be used, but among these, an anthrone type which is inexpensive and stable in performance is preferable. The thickness of the release sheet 6 is not particularly limited, but is usually about 20 to 250 μm.

5. Method for producing a composite sheet for forming a protective film

It is preferable to form the first laminate including the protective film forming film 1 and the second laminate including the support sheet 4, and then laminate the protective film forming film 1 and the support sheet 4 by using the first laminate and the second laminate. Thus, the composite sheet 3 for forming a protective film can be produced, but the invention is not limited thereto.

In the production of the first layered product, the protective film forming film 1 is formed on the peeling surface of the first release sheet. Specifically, the coating agent for a protective film forming film is prepared, and the coating agent for a protective film forming film contains a curable adhesive constituting the protective film forming film 1 and may further contain a solvent if necessary, and further a roll coater or a knife. A coater such as an applicator, a roll coater, an air knife coater, a die coater, a bar coater, a gravure coater, or a curtain coater is applied onto the peeling surface of the first release sheet and dried to form a protective film forming film 1 . Connect The peeling surface of the second release sheet is pressed against the exposed surface of the protective film forming film 1 to obtain a laminated body (first laminated body) in which the protective film forming film 1 is sandwiched between two peeling sheets.

In the first layered product, a half cut line may be applied from the side of the first release sheet or the second release sheet by cutting or laser irradiation to form the protective film forming film 1 (and the second release sheet). For the shape sought, for example, a circle or the like. At this time, the excess portion of the protective film forming film 1 and the second peeling sheet which are generated by the half tangential line can be appropriately removed.

In the production of the second layered product, the coating agent for the pressure-sensitive adhesive layer is applied to the release surface of the third release sheet, and the coating agent for the pressure-sensitive adhesive layer contains the adhesive constituting the pressure-sensitive adhesive layer 42 and may be further contained if necessary. The solvent is dried to form an adhesive layer 42. Thereafter, the substrate 41 is pressed against the exposed surface of the adhesive layer 42 to obtain a laminate (second laminate) including the support sheet 4 and the third release sheet, and 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 may be irradiated with an energy ray and the adhesive layer 42 may be cured at this stage, or may be hardened and adhered after lamination with the protective film forming film 1. Agent layer 42. Moreover, when the adhesive layer 42 is hardened after laminating with the protective film forming film 1, the adhesive layer 42 can be hardened before the dicing step, and the adhesive layer 42 can be hardened after the dicing step.

The energy rays usually use ultraviolet rays, electron wires, and the like. The amount of irradiation of the energy ray varies depending on the type of the energy ray. For example, the amount of ultraviolet light is preferably 50 to 1000 mJ/cm ² , more preferably 100 to 500 mJ/cm ² . Further, the electronic wire is preferably about 10 to 1000 krad.

When the first laminate and the second laminate are obtained as described above, the second release sheet in the first laminate is peeled off, and the third release sheet in the second laminate is peeled off, and the first laminate is exposed. The film formation layer 1 and the adhesive layer 42 of the support sheet 4 in which the second laminate is exposed are superposed and pressed. The support sheet 4 is subjected to a half tangent as needed, and may be formed into a circular shape having a desired shape, for example, a diameter larger than that of the protective film forming film 1. At this time, the excess portion of the support sheet 4 produced by the half tangent can be appropriately removed.

Thus, the composite sheet 3 for forming a protective film is obtained by including a support sheet 4 in which an adhesive layer 42 is laminated on a substrate 41, a protective film forming film 1 laminated on the side of the adhesive layer 42 of the support sheet 4, and a laminate. The first release sheet on the side opposite to the support sheet 4 in the protective film forming film 1. After the first release sheet is peeled off, the adhesive layer 5 for the jig is formed on the edge portion of the protective film formation film 1 on the side opposite to the support sheet 4. The adhesive layer 5 for a jig can be formed by coating in the same manner as the above-described adhesive layer 42.

6. Method of using composite sheet for forming a protective film

It is used as one of the composite sheets 3 for forming a protective film in the present embodiment. For example, a method of manufacturing a wafer having a protective film from a semiconductor wafer as a workpiece will be described below.

First, the wound-sheet-formed composite film 3 for protective film formation is pulled out, and as shown in FIG. 2, the protective film forming film 1 of the composite sheet for protective film formation 3 is attached to the semiconductor wafer 7, and the jig is adhered. The agent layer 5 is attached to the annular frame 8.

In the composite sheet 3 for forming a protective film of the present embodiment, the arithmetic mean roughness (Ra1) before heating of the back surface of the substrate 41 is 0.2 μm or more, and adhesion is less likely to occur during the drawing, and the stretching can be suppressed. A bad occurrence occurs and it cannot be attached to the workpiece.

After that, the protective film forming film 1 is cured to form a protective film, and a laminated structure (hereinafter referred to as "stacked structure L") having a protective film laminated on the surface of the support sheet 4 on the side of the adhesive layer 42 is obtained. In the semiconductor wafer 7, the support sheet 4 has a function as an extensible dicing sheet. The laminated structure L shown in Fig. 2 further includes an adhesive layer 5 for a jig and an annular 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 a suitable period of time. Moreover, when the protective film forming film 1 is not a thermosetting adhesive, another heat treatment is performed.

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

As described above, the laminated structure L including the semiconductor wafer 7 having the protective film is obtained, and then the protective film is irradiated with laser light so as to penetrate the supporting sheet 4, and laser printing is performed.

Next, the laminated structure L is subjected to a stealth laser wafer cutting step. Specifically, the laminated structure L is placed in the laser irradiation device for division processing, and after the surface position of the semiconductor wafer 7 covered by the protective film 1 is found, the semiconductor wafer 7 is penetrated by the support sheet 4 . The laser beam is irradiated to form a modified layer in the semiconductor wafer 7. Thereafter, the support sheet 4 having the function as a dicing sheet is stretched by performing the stretching step, and the semiconductor wafer 7 having the protective film is biased (the pulling force in the main surface direction). As a result, the semiconductor wafer 7 having the protective film attached to the support sheet 4 is divided to obtain a wafer having a protective film (having a protective film wafer). Thereafter, the wafer having the protective film is taken out from the support sheet 4 by using the take-up device.

In the composite sheet 3 for forming a protective film of the present embodiment, the arithmetic mean roughness (Ra2) after heating of the back surface of the substrate 41 is 0.25 μm or less, and the laser light transmittance is excellent. In the step of printing a word, it is possible to form a printing which is excellent in laser printing and has high visibility. Moreover, in the stealth laser wafer cutting step, the workpiece segmentation by the stealth laser wafer is excellent.

7. Other Embodiments of Composite Sheet for Forming Protective Film

Fig. 3 is a cross-sectional view showing a composite sheet for forming a protective film according to another embodiment of the present invention. As shown in FIG. 3, the composite sheet 3A for protective film formation of the present embodiment has a support sheet 4 composed of an area-layer adhesive layer 42 laminated on one side of the 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 peeling sheet 6 laminated on the side opposite to the supporting sheet 4 of the protective film forming film 1 are formed. The protective film forming film 1 of the present embodiment is formed such that the surface direction thereof 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 which is not laminated with the protective film forming film 1 can be attached to a jig such as an annular frame.

The material and thickness of each member of the composite sheet 3A for forming a protective film of the present embodiment are the same as the material and thickness of each member of the composite sheet 3 for forming a protective film. When the adhesive layer 42 is formed of an energy ray-curable adhesive, it is preferred that the energy ray-curable adhesive in the portion of the adhesive layer 42 that is in contact with the protective film forming film 1 is hardened, and the energy of other portions is not made. The wire hardenable adhesive hardens. Thereby, the smoothness (gloss) of the protective film of the cured protective film forming film 1 can be improved, and the high adhesion force to the jig such as the ring frame can be maintained.

Further, in the adhesive layer 42 of the support sheet 4 of the protective film-forming composite sheet 3A, the edge portion on the side opposite to the base material 41 may be provided with an adhesive for the jig of the protective film-forming composite sheet 3 Layer 5 is the same With adhesive layer.

Further, the support sheet 4 of the present embodiment may be composed of the base material 41 without the adhesive layer 42. At this time, the surface of the base material 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 base material 41 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 the adhesive layer 5 for a jig as shown in Fig. 1 at the edge portion on the opposite side of the base material 41 (support sheet 4) in the protective film forming film 1.

The embodiments described above are based on the ease of understanding of the invention and are not intended to limit the invention. Therefore, each element disclosed in the above-described embodiments includes all design changes and equivalents in the technical scope of the present invention.

For example, in the support sheet 4, other layers may be present between the substrate 41 and the adhesive layer 42. Further, the other layer of the first area layer of the support sheet 4 composed of the base material 41 can be used.

Further, in the composite sheet for forming a protective film of the present invention, the arithmetic mean roughness (Ra1) before heating of the back surface of the substrate 41 is about 0.51 to 0.65 μm, and the arithmetic mean roughness after heating at 130 ° C for 2 hours. (Ra2) is about 0.08 to 0.22, and the storage elastic modulus of the substrate 41 at 130 ° C is about 13 to 20 MPa, so that the light transmittance after heating is 532nm is about 73~91%, and it is about 77~91% at 1064nm, which can make the adhesion resistance, laser printing and cutting and segmentation more excellent.

(Example)

Hereinafter, the present invention will be specifically described by way of Examples and the like, but the scope of the present invention is not limited to the Examples.

[Example 1]

In the first embodiment, the composite sheet 3 for forming a protective film shown in Figs. 3 and 4 was produced in the following manner.

(1) Making a first layered body containing a protective film forming film

The following components were mixed in a blending ratio (converted to a solid content), and diluted with methyl ethyl ketone to have a solid content concentration of 61% by mass to prepare a coating agent for a protective film forming film.

(A) Adhesive polymer: 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) The acrylate copolymer (weight average molecular weight: 800,000, glass transition temperature: -1 ° C) was 100 mass parts.

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

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

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

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

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

(E) cerium oxide filler (SC2050MA, manufactured by Admatech Co., Ltd., average particle diameter: 0.5 μm) was 320 mass%.

(F) Colorant: Soot (#MA650, manufactured by Mitsubishi Chemical Corporation, average particle diameter: 28 nm) 0.6 mass%.

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

First, the coating film for a protective film forming film was applied by a knife coater so that the thickness of the finally obtained protective film forming film was 25 μm on the peeling surface of the first release sheet (SP-PET 3811, thickness: 38 μm, manufactured by Lintec Co., Ltd.). The film was formed by drying at 120 ° C for 2 minutes to form a protective film. Then, the peeling surface of the second release sheet (SP-PET381031 manufactured by Lintec Co., Ltd., thickness: 38 μm) was superposed on the protective film forming film, and the two were bonded together to obtain a first release sheet (the release sheet 6 in FIGS. 3 and 4). The protective film forming film (the protective film forming film 1 in FIGS. 3 and 4) and the laminated body composed of the second peeling sheet. This laminated system is elongated and rolled into a roll to form a wound.

The wound body of the long laminated body obtained as described above was cut 300 mm in the width direction (shown by w ₁ in Fig. 4). Then, the layered body is continuously circularly formed on the second peeling sheet side in the center portion in the width direction of the laminated body so that the second peeling sheet and the protective film forming film are cut (diameter d ₁ : 220 mm; FIG. 4 The half tangent of the symbol 101). Thereafter, the second release sheet and the protective film forming film which are present on the outer side of the circle formed by the half tangential line are removed. In this way, the first layered product is obtained, and a circular protective film forming film is laminated on the peeling surface of the first peeling sheet, and a circular second peeling sheet is laminated on the circular protective film forming film. .

(2) Making a second layered body containing a support sheet

The following components (H) and (I) were mixed and diluted with methyl ethyl ketone to have a solid content concentration of 30% by mass to prepare a coating agent for an adhesive layer.

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

(I) Crosslinking agent: 10 parts by mass of an aromatic polyisocyanate compound (TAKENATE D110N manufactured by Mitsui Chemicals, Inc.).

Next, the arithmetic mean roughness (Ra1) before heating (the back surface of the base material (the second surface of the support sheet)) and the arithmetic mean roughness (Ra2) after heating (130 ° C, 2 hours), The melting point and the storage modulus of 130 ° C were adjusted to form an ethylene/propylene copolymer film as shown in the following Table 1, and the other side of the film was subjected to corona treatment as a substrate. Further, the arithmetic mean roughness (Ra1) before the 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 at the time of film formation of the substrate. Further, the arithmetic mean roughness (Ra2) after the heating was adjusted by adjusting the copolymerization ratio of ethylene and propylene of the ethylene/propylene copolymer constituting the substrate.

A release sheet (SP-PET381031 manufactured by Lintec Co., Ltd.) having a ketone-based release agent layer formed on one surface of a PET film having a thickness of 38 μm was prepared, and the thickness of the resulting protective film-forming film was 10 μm on the release surface of the release sheet. In the manner, the coating agent for an adhesive layer is applied by a knife coater, and dried to form an adhesive layer. Thereafter, the corona-treated surface of the base material is superposed on the adhesive layer, and the two are bonded to each other to obtain a second laminate. The second laminate system includes a support sheet (support sheet 4 of FIGS. 3 and 4) and a release sheet. The support sheet includes a substrate (substrate 41 of FIG. 3) and an adhesive layer (adhesive layer 42 of FIG. 3). The laminated body was elongated, and was wound into a wound body and then cut 300 mm in the width direction (shown by w ₁ in Fig. 4).

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

The first laminate obtained by the above (1) is peeled off from the circular second release sheet to expose a circular protective film formation film. On the other hand, the second laminate obtained in the above (2) is peeled off from the release sheet to expose the adhesive layer. The first laminate and the second laminate are bonded to each other so that the protective film forming film contacts the pressure-sensitive adhesive layer, thereby obtaining a support sheet, a protective film forming film, and a first peeling layer which are composed of a base material and an adhesive layer. The third layer Laminated body.

Next, in the third laminate, a half tangent is applied so as to cut the support sheet (base material and adhesive layer) from the substrate side. Specifically, as shown in FIG. 4, a circular circle having a concentric circle larger than the circular protective film forming film (diameter d ₁ : 220 mm) is formed (diameter d ₂ : 270 mm; symbol 401 in FIG. 4; The support piece is formed, and an arc having a 20 mm interval (shown by w ₂ in Fig. 4) is formed outside the circular shape (symbol 402 in Fig. 4). Further, two straight lines (symbol 403 in FIG. 4) parallel to the end portions in the width direction of the third layered body are formed between the adjacent two circles, and the adjacent arcs are connected to the straight line.

Thereafter, the portion between the circular support piece and the arc and the portion of the two straight lines are removed, and a composite sheet for forming a protective film as shown in Figs.

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

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

[Test Example 1] <Measurement of arithmetic mean roughness of substrate>

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

Here, the arithmetic mean roughness (Ra2) after heating is in a state in which the composite sheet for forming a protective film of the examples and the comparative examples having the above-mentioned substrate is fixed to an annular frame, and is 130 ° C in an atmosphere in an oven. After heating for 2 hours, it was allowed to stand and the value after cooling to room temperature was measured. During the heat treatment, the measurement surface (the back surface of the substrate) does not contact the inner wall and the bottom of the oven.

[Test Example 2] <Measurement of melting point of substrate>

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

[Test Example 3] <Measurement of storage elastic modulus of substrate>

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

Measuring device: TA Instruments Brake modulus measuring device "DMA Q800".

Test start temperature: 0 °C.

End temperature of test: 200 ° C.

Heating rate: 3 ° C / min.

Frequency: 11Hz.

Amplitude: 20 μm.

[Test Example 4] <Measurement of light transmittance>

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

[Test Example 5] <Evaluation of Adhesion Resistance>

The first release sheet was peeled off from the composite sheet for forming a protective film produced in the examples and the comparative examples. Using the sticking device (RAD-2700F/12 manufactured by Lintec Co., Ltd.), the obtained composite sheet for forming a protective film was adhered to a tantalum wafer by a roll-to-roll method at 70 ° C (outer diameter: 8 吋, Thickness: 100 μm) and ring frame (made of stainless steel). At this time, 10 sheets of the sticking operation were 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 adhered without problems (no adhesion at all).

B: Although the base material is in close contact with the release sheet portion on the back side of the substrate, the partial release sheet is peeled off by the adhesive layer or the protective film formation film when the composite sheet for forming a protective film is pulled out.

C: A peeling sheet in which at least one sheet is transferred to the back side of the substrate, or a sheet in which the protective film is formed cannot be pulled out, and the adhesion is poor (cohesion occurs).

[Test Example 6] <Evaluation of Laser Printing Ability>

The first release sheet was peeled off from the composite sheet for forming a protective film produced in the examples and the comparative examples. The obtained composite sheet for forming a protective film was adhered to a tantalum wafer (outer diameter: 8 Å, thickness: 100 μm) and a ring shape at 70 ° C using a sticking device (RAD-2700 F/12 manufactured by Lintec). Rack (stainless steel). Thereafter, the film was heat-treated at 130 ° C for 2 hours to thermally cure the protective film forming film to form a protective film.

Next, using a printing device (MD-T1000 manufactured by Keyence Corporation), the protective film was irradiated with laser light having a wavelength of 532 nm through the support sheet, and the protective film was subjected to laser printing under the following conditions.

Condition 1...Text size: 0.4mm×0.5mm, text interval: 0.3mm, number of characters: 20 characters

Condition 2...Text size: 0.2mm×0.5mm, text interval: 0.3mm, number of characters: 20 characters

The visibility of the laser-printed characters formed on the protective film by the protective film (laser printing property) was evaluated according to the following criteria. The results are shown in Table 1 below.

A: All the words of conditions 1 and 2 can be read smoothly.

B: Condition 2 has an unclear part, but can read condition 1 smoothly. All the text.

C: Both conditions 1 and 2 have unclear parts.

[Test Example 7] <Evaluation of cutting and segmentation>

The first release sheet was peeled off from the composite sheet for forming a protective film produced in the examples and the comparative examples. The obtained composite sheet for forming a protective film was adhered to a tantalum wafer (outer diameter: 8 Å, thickness: 100 μm) and a ring shape at 70 ° C using a sticking device (RAD-2700 F/12 manufactured by Lintec). Rack (stainless steel). Thereafter, the film was heat-treated at 130 ° C for 2 hours to thermally cure the protective film forming film to form a protective film.

Next, for the obtained wafer having the protective film, a laser cutter (DFL 7360 manufactured by DISCO Corporation) was used to perform the slitting process of the stealth laser wafer cutting, and the above-described stealth laser wafer cutting system includes the following steps.

(Step 1) The specific position of the laser cutter is set so that the enamel wafer and the ring frame of the composite sheet for forming a protective film of the embodiment and the comparative example can be irradiated with laser light from the side of the support sheet (the back side of the substrate). .

(Step 2) After detecting the surface position of the germanium wafer covered by the protective film, set the focus position of the laser light of the laser cutter to form a wafer body of 9 mm × 9 mm on the wafer with the protective film, along the way A predetermined line is cut, and 10 times of laser light having a wavelength of 1064 nm derived from a laser cutter is irradiated from the side of the protective film to form a modified layer in the germanium wafer.

(Step 3) The crucible wafer and the ring frame to which the composite film for protective film formation is adhered are placed on a wafer divider (DDS2300 manufactured by DISCO Corporation). The speed is 100 mm/sec and the extension is 10 mm for extension.

By the above steps, at least a part of the germanium wafer in which the reforming layer is formed is divided along the dividing line to obtain a plurality of wafers having a protective film. According to the division ratio (= (the number of wafers actually divided/the number of wafers to be divided) × 100) (%) at this time, the cut splitting property was evaluated on the basis of the following criteria. The results are shown in Table 1.

A: The wafer division ratio is 100% (excellent segmentation).

B: The wafer division ratio is 90% or more and less than 100% (with acceptable segmentation).

C: The wafer division ratio is 80% or more and less than 90% (with acceptable segmentation).

D: The wafer division rate is less than 80% (does not have acceptable segmentation).

As is clear from Table 1, the arithmetic mean roughness (Ra1) before heating on the back surface of the substrate was 0.2 μm or more, and the arithmetic flat after heating at 130 ° C for 2 hours on the back surface of the substrate The composite sheet for forming a protective film of the example having a uniform thickness (Ra2) of 0.25 μm or less is excellent in adhesion resistance, and is excellent in laser printing property and cutting property.

(industry availability)

The composite sheet for forming a protective film of the present invention is suitable for use in a case including a step of irradiating laser light by penetrating a substrate, such as laser printing and stealth laser wafer cutting.

1‧‧‧Protective film forming film

3‧‧‧Composite film for protective film formation

4‧‧‧Support tablets

41‧‧‧Substrate

42‧‧‧Adhesive layer

5‧‧‧Adhesive adhesive layer

6‧‧‧ peeling film

Claims (11)

A composite sheet for forming a protective film, comprising a support sheet and a protective film forming film laminated on the first surface side of the support sheet; and an arithmetic mean roughness (Ra1) of the second surface of the support sheet is 0.2 μm or more; After the support sheet was heated at 130 ° C for 2 hours, the arithmetic mean roughness (Ra 2 ) of the second surface of the support sheet was 0.25 μm or less. The composite sheet for forming a protective film according to claim 1, wherein the arithmetic mean roughness (Ra2) after the heating of the second surface of the support sheet is smaller than the arithmetic mean roughness (Ra1). The composite sheet for forming a protective film according to claim 1, wherein the support sheet comprises a base material and an adhesive layer which is one side of the base material and is laminated on the first surface side of the support sheet; or The aforementioned support sheet comprises a substrate. The composite sheet for forming a protective film according to claim 3, wherein the base material has a melting point of 90 to 180 °C. The composite sheet for forming a protective film according to claim 3, wherein the substrate has a storage modulus at 130 ° C of 1 to 100 MPa. The composite sheet for forming a protective film according to claim 3, 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 3, wherein the substrate has a light transmittance of 40% or more at a wavelength of 532 nm after the heating. The composite sheet for forming a protective film according to claim 3, wherein the substrate is a film composed of a copolymer of ethylene and propylene. The composite sheet for forming a protective film according to any one of claims 1 to 8, wherein the composite sheet for forming a protective film has an adhesive layer for a jig, and the adhesive layer for the jig is laminated on the protective film. An edge portion of the film opposite to the side of the support sheet. The composite sheet for forming a protective film according to any one of claims 1 to 8, which has a release sheet, and the release sheet is laminated on the protective film formation film. The composite sheet for forming a protective film according to any one of the preceding claims, wherein the protective film forming film is a layer formed on a semiconductor wafer or a semiconductor wafer obtained by cutting a semiconductor wafer to form a protective film.