TWI706023B - Sheet for forming protective film and method of manufacturing tip having protective film - Google Patents

Abstract

A sheet for forming a protective film which includes a first supporting sheet and a film for forming a protective film laminated on a first surface side of the first supporting sheet, wherein the film for forming the protective film is composed of a curable material and has following properties: when the film for forming the protective film is cured to form the protective film, the breaking strain of the protective film at 50℃ is 20% or less and the breaking stress of the protective film at 50℃ is 2.0×10⁷Pa or less.

Description

Sheet for forming protective film and method for manufacturing wafer with protective film

The present invention relates to a sheet for forming a protective film, which can form a protective film on a workpiece such as a semiconductor wafer or a processed object (such as a semiconductor wafer) that can be processed on the aforementioned workpiece.

This case is based on Japanese Patent Application No. 2014-169266 and Japanese Patent Application No. 2014-169267 filed in Japan on August 22, 2014, and claims priority, and the content is quoted herein.

In recent years, semiconductor devices have been manufactured using 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, it is a structure in which the back surface side of the semiconductor wafer on which the circuit is not formed is exposed.

Patent Documents 1 and 2 disclose a protective film forming/cutting integrated sheet (that is, a protective film forming sheet) in which a protective film forming layer (that is, a protective film forming film) capable of forming the above protective film is formed on an adhesive sheet. In this protective film forming/cutting integrated sheet, the protective film forming film is cured by heat treatment to form the protective film. That is, with the above-mentioned protective film forming/dicing integrated sheet, both the dicing of the semiconductor wafer and the formation of the protective film on the semiconductor wafer can be performed, and the semiconductor wafer with the protective film can be obtained.

On the other hand, when manufacturing processed objects including semiconductor wafers and other flakes from workpieces such as semiconductor wafers, conventionally, knife cutting is usually performed. While blowing liquid for cleaning purposes on the workpiece, it is cut with a rotary knife. The workpiece is broken to obtain a flake. However, in recent years, stealth dicing (registered trademark; the same below) processing that can be divided into slices in a dry manner has been adopted.

For example, Patent Document 3 discloses the following invisible dicing method: a laminated adhesive sheet (comprising two layers of an adhesive sheet including a base material and an adhesive layer) is attached to an extremely thin semiconductor wafer, and the laminated adhesive is self-adhesive The sheet side passes through the laminated adhesive sheet to irradiate the semiconductor wafer with laser light, and after forming a modified portion inside the semiconductor wafer, the adhesive sheet is extended to divide the semiconductor wafer along the cutting line and produce the semiconductor wafer.

[Previous technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2012-33637

Patent Document 2: Japanese Patent Laid-Open No. 2011-151362

Patent Document 3: Japanese Patent No. 3762409

The above-mentioned invisible dicing is to extend the adhesive sheet to divide the semiconductor wafer. Therefore, it is also preferable to divide the components between the adhesive sheet and the semiconductor wafer in the same manner as the semiconductor wafer. When such a member is a protective film forming film, in order to realize proper division, the protective film forming film may be cooled.

The object of the present invention is to provide a protective film forming sheet with a protective film forming film, which is used in invisible dicing, when the member located between the adhesive sheet and a workpiece such as a semiconductor wafer is a protective film formed by the protective film forming film When extending the adhesive sheet, the protective film can be divided appropriately. In addition, as another aspect, an object of the present invention is to provide a method of manufacturing a processed product such as a semiconductor wafer with a protective film using the protective film forming sheet.

The present invention provided in order to achieve the above object includes the following aspects.

(1) A sheet for forming a protective film comprising a first support sheet and a protective film forming film laminated on the first surface side of the first support sheet, the protective film forming film includes a curable material, and the protective film forming film The hardened protective film has a breaking strain of 20% or less at 50°C, and a breaking stress of 2.0×10 ⁷ Pa or less at 50°C.

(2) The protective film forming sheet as described in (1) above, wherein the storage modulus of the protective film at 25°C is 3.0×10 ⁹ Pa or more.

(3) The sheet for forming a protective film as described in (1) or (2) above, wherein the loss tangent of the protective film at 25°C is 0.4 or less.

(4) The sheet for forming a protective film as described in any one of (1) to (3) above, wherein the protective film has a light transmittance of 40% or more at a wavelength of 1064 nm.

(5) The protective film forming sheet as described in any one of (1) to (4) above, which includes a second support sheet laminated on the protective film forming film and facing the first support sheet The opposite side of the face.

(6) A method of manufacturing a wafer with a protective film, comprising: an attaching step of making the protective film included in the protective film forming sheet described in any one of (1) to (5) above The surface of the formed film opposite to the surface facing the first support sheet is exposed, and the surface is attached to one surface of the workpiece to obtain a first laminate including the protective film forming sheet and the workpiece; The curing step is to harden the protective film forming film of the protective film forming sheet of the first laminate to obtain the protective film; the first dividing step is to obtain the protective film after passing through the first curing step. While the temperature of the protective film included in the protective film forming sheet of the laminate is maintained in the range of 40°C to 70°C, the first support sheet included in the protective film forming sheet is extended to extend the The protective film is divided together with the work piece to obtain a second layered body. The second layered system is provided with a plurality of layers of the work piece and the protective film divided on one surface of the first support sheet. Film wafers; and the first picking step is to separate the plurality of protective film-attached wafers provided in the second laminate from the first support sheet to obtain the protective film-attached wafers as processed objects ; And before starting the first dividing step, a modified layer forming step is performed, which is to irradiate laser light in the infrared region to focus on the focal point set inside the workpiece, and the modified layer is formed inside the workpiece.

(7) A method for manufacturing a wafer with a protective film, comprising: a lamination step of forming the protective film included in the protective film forming sheet described in any one of (1) to (5) above The surface of the film opposite to the surface facing the first support sheet is exposed, the surface is attached to one surface of the workpiece, and the first support sheet of the protective film forming sheet is formed into a film from the protective film Peel off to obtain a third laminate including the workpiece and the protective film forming film; the second curing step is to harden the protective film forming film of the third laminate to obtain the protective film; second attachment The step is to combine the surface on the third adhesive layer side of the processing sheet with the third substrate and the third adhesive layer laminated on one surface side of the third substrate, and the surface of the processing sheet that has undergone the second curing step. The surface of the third layered body on the side of the protective film is bonded to obtain a fourth layered body including the processing sheet and the third layered body; the second dividing step is to assemble the aforementioned fourth layered body with While maintaining the temperature of the protective film in the range of 40°C to 70°C, the processing sheet included in the fourth laminate is extended, and the protective film is divided together with the workpiece to obtain a fifth laminate, The fifth layered system is provided with a plurality of protective film-attached wafers formed by dividing the workpiece and the layered body of the protective film on one surface of the processing sheet; and the second pick-up step is to layer the fifth The plurality of protective film-attached wafers included in the body are respectively separated from the processing sheet to obtain the protective film-attached wafer as a processed product; and the modified layer forming step is performed before the second division step is started In the step of forming the modified layer, laser light in the infrared region is irradiated to focus on the focal point set inside the workpiece to form the modified layer inside the workpiece.

That is, the present invention includes the following aspects.

[1] A protective film forming sheet comprising a first support sheet and a protective film forming film laminated on the first surface side of the first support sheet; the protective film forming film includes a curable material; and the protective film is formed The film has the following characteristics: when the protective film is hardened to become a protective film, the breaking strain at 50°C of the protective film is 20% or less, and the breaking stress at 50°C is 2.0×10 ⁷ Pa or less.

[2] The protective film forming sheet as described in [1], wherein the protective film forming film further has the following characteristics: the storage modulus of the protective film at 25° C. is 3.0×10 ⁹ Pa or more.

[3] The protective film forming sheet as described in [1] or [2], wherein the protective film forming film further has the following characteristics: the loss tangent of the protective film at 25°C is 0.4 or less.

[4] The protective film forming sheet as described in any one of [1] to [3], wherein the protective film forming film further has the following characteristics: the protective film has a wavelength of 1064 nm and a light transmittance of 40% the above.

[5] The sheet for forming a protective film as described in any one of [1] to [4], wherein the sheet for forming a protective film further includes a second support sheet, which is laminated on the protective film forming film and faces the The surface side opposite to the surface of the first support piece.

[6] A method for manufacturing a wafer with a protective film, comprising: an attaching step of forming a film of the protective film included in the protective film forming sheet described in any one of [1] to [5] The surface opposite to the surface facing the first support sheet is exposed, and the exposed surface is attached to one surface of the workpiece to obtain a first laminate including the protective film forming sheet and the workpiece; 1 Curing step, which is to obtain the protective film by curing the protective film forming film in the first layered body; the first dividing step is to obtain the protective film in the first layered body that has undergone the first curing step While the temperature of the protective film is kept in the range of 40°C to 70°C, the first support sheet is extended, and the protective film is divided together with the workpiece to obtain a second laminate. The second laminate system is A plurality of protective film-attached wafers formed by dividing the laminate of the workpiece and the protective film in the thickness direction are arranged on one surface of the first support sheet; and the first picking step is Separating the plurality of protective film-attached wafers included in the second layered body from the first support sheet to obtain the protective film-attached wafer as a processed product; and further comprising a modified layer forming step, Before starting the first dividing step, laser light in the infrared region is irradiated to focus on a focal point set inside the workpiece to form a modified layer inside the workpiece.

[7] A method of manufacturing a wafer with a protective film, comprising: a lamination step of forming a film of the protective film included in the protective film forming sheet described in any one of [1] to [5] The surface opposite to the surface facing the first support sheet is exposed, the exposed surface is attached to one surface of the work, and the first support sheet is peeled from the protective film forming film to obtain The third layered body of the work and the protective film forming film; the second curing step is to obtain the protective film by curing the protective film forming film of the third layered body; the second attaching step is In a processing sheet comprising a third base material and a third adhesive layer laminated on one side of the third base material, the surface on the side where the third adhesive layer is laminated, and the surface that has undergone the second curing step The surface of the protective film side of the third laminate is bonded to obtain a fourth laminate including the processing sheet and the third laminate; the second dividing step is to combine the fourth laminate with While maintaining the temperature of the protective film in the range of 40°C to 70°C, the processing sheet included in the fourth laminate is extended, and the protective film is divided together with the workpiece to obtain the fifth A laminated body in which the fifth laminated system is provided with a plurality of protective film-attached wafers formed by dividing the laminated body of the workpiece and the protective film on one surface of the processing sheet such that a cut surface is generated in the thickness direction ; And the second picking step is to separate the plurality of protective film-attached wafers provided in the fifth laminate from the processing sheet to obtain the protective film-attached wafer as a processed product; and further includes The step of forming the modified layer is to irradiate laser light in the infrared region to focus on the focal point set inside the workpiece before starting the second dividing step to form the modified layer inside the workpiece.

According to the protective film forming sheet of the present invention, even the member in which the protective film formed by the protective film forming film is located between the adhesive sheet and the workpiece such as a semiconductor wafer can be appropriately divided when the adhesive sheet is extended during stealth dicing Protective film. Therefore, a semiconductor wafer with a protective film can be manufactured stably.

1‧‧‧Protection film forming film

3, 3A, 3B‧‧‧Protection film forming sheet

4‧‧‧Support sheet

41‧‧‧Substrate

42‧‧‧Adhesive layer

5‧‧‧Adhesive layer for fixture

6‧‧‧Release sheet

7‧‧‧Semiconductor wafer

8‧‧‧Ring frame

9‧‧‧Chip with protective film

10‧‧‧Layer 1

11, 20‧‧‧Layer 2

12‧‧‧Layer 3

13‧‧‧Processing film

131‧‧‧The third adhesive layer

132‧‧‧The third substrate

14‧‧‧Layer 4

R‧‧‧Ring member

P‧‧‧ jacking pin

C‧‧‧Vacuum suction collet

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

Fig. 2 is a cross-sectional view conceptually showing a state after the release sheet is peeled off from the protective film forming sheet according to the embodiment of the present invention.

3 is a cross-sectional view conceptually showing the first laminate obtained through the first attaching step included in the method of manufacturing a chip with a protective film according to an embodiment of the present invention.

4 is a cross-sectional view conceptually showing a second laminate obtained through the first dividing step included in the method for manufacturing a wafer with a protective film according to an embodiment of the present invention.

Fig. 5 is a cross-sectional view conceptually showing a state in which the first pick-up step included in the method of manufacturing a wafer with a protective film according to an embodiment of the present invention is implemented.

Fig. 6 is a cross-sectional view conceptually showing a sheet for forming a protective film according to another embodiment of the present invention.

7 is a cross-sectional view conceptually showing a third laminate obtained through the lamination steps included in the method of manufacturing a wafer with a protective film according to another embodiment of the present invention.

8 is a cross-sectional view conceptually showing a fourth laminate obtained through the second attaching step included in the method for manufacturing a chip with a protective film according to another embodiment of the present invention.

9 is a cross-sectional view conceptually showing a fifth laminate obtained through the second dividing step included in the method of manufacturing a wafer with a protective film according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view conceptually showing a state in which the second pickup step included in the method of manufacturing a chip with a protective film according to another embodiment of the present invention is implemented.

Fig. 11 is a cross-sectional view conceptually showing a sheet for forming a protective film according to another embodiment of the present invention.

The embodiments of the present invention will be described below.

Fig. 1 is a cross-sectional view of a protective film forming sheet according to an embodiment of the present invention. As shown in FIG. 1, the protective film forming sheet 3 of this embodiment is configured to include: a first support sheet 4; a protective film forming film 1, which is laminated on one surface of the first support sheet 4 ("the first surface" described later) 1 is the upper surface) side; and the jig adhesive layer 5, which is laminated in the protective film forming film 1 and the surface facing the first support sheet 4 on the opposite side of the peripheral edge. The adhesive layer 5 for jigs is a layer for adhering the sheet 3 for forming a protective film to jigs such as a ring frame. In addition, the protective film forming sheet 3 of this embodiment includes a peeling sheet 6 on the protective film forming film 1 and the jig adhesive layer 5 (on the opposite side to the first support sheet 4). The peeling sheet 6 is a sheet to be peeled and removed when the sheet 3 for forming a protective film is used, and is not an essential constituent element in the sheet 3 for forming a protective film.

That is, one form of the protective film forming sheet according to an embodiment of the present invention includes: a first support sheet 4; a protective film forming film 1 laminated on one side of the first support sheet 4; and an adhesive layer 5 for jigs , Is laminated on the periphery of the protective film forming film 1 and the surface facing the first support sheet 4 on the opposite side; and if necessary, the peeling sheet 6 is laminated on the protective film forming film 1 and the adhesive for jigs剂层5上。 Agent layer 5.

The protective film forming sheet 3 of this embodiment is used for attaching to the workpiece and holding the workpiece when processing the workpiece, and forming a protective film on the workpiece or the processed product obtained by processing the workpiece. The protective film is composed of a cured protective film forming film 1.

As an example, the protective film forming sheet 3 of this embodiment is used to hold a semiconductor wafer during the dicing process of a semiconductor wafer as a work, and to form a protective film on the semiconductor wafer obtained by dicing, but it is not limited Here.

The sheet 3 for forming a protective film of the present embodiment is generally formed in a long strip shape and wound into a roll shape, and is used in a roll to roll method.

1. Support sheet

The first support sheet 4 of the protective film forming sheet 3 of one embodiment of the present invention is provided with a base material 41 and laminated on one surface side of the base material 41 (that is, the side of the laminated protective film forming film 1; the upper side in FIG. 1 ) Is composed of an adhesive layer 42. Here, the surface on the side of the laminated protective film forming film 1 of the first 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 first support sheet 4, the adhesive layer 42 is laminated on the first surface side of the first support sheet 4, and the base material 41 is laminated on the second surface side of the first support sheet 4.

1-1. Substrate

The base material 41 of the protective film forming sheet 3 of one embodiment of the present invention is not particularly limited as long as it is a base material generally used as a base material of an adhesive sheet for stealth dicing. The base material 41 may have a single-layer structure or a multilayer structure. The protective film forming film 1 is a film in which a protective film is formed by heating. When the protective film forming film 1 is heated in order to form the protective film, the substrate 41 is also heated. It is required that the substrate 41 is heated after the heating. Appropriate use (for example, a substrate that can be stretched appropriately, etc.) is used.

From this viewpoint, 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.

The method of adjusting the melting point of the base material 41 is not particularly limited, and usually can be adjusted mainly by using the melting point of the resin material used. In addition, it is also possible to adjust to an arbitrary melting point by mixing a plurality of resin materials with different melting points or copolymerizing a plurality of monomers.

The storage modulus of the base material 41 at 130° C. is preferably 1 MPa-100 MPa. By setting the storage modulus at 130° C. within the above range, the heat resistance of the base material 41 can be ensured, and the possibility of defects when the first support sheet 4 is stretched is reduced. From the viewpoint of both improving the heat resistance of the base material 41 and facilitating the extension of the first support sheet 4, the storage modulus of the base material 41 at 130°C is more preferably 2 MPa to 80 MPa, and particularly preferably 5 MPa to 50 MPa. In addition, the measurement method of the above-mentioned storage modulus is as shown in the test example described later.

The method of adjusting the storage modulus of the base material 41 at 130° C. is not particularly limited, and the storage modulus of the resin material used can usually be used for adjustment. In addition, even with the same chemical structure, the storage modulus tends to increase if the molecular weight is high, and the storage modulus tends to increase due to crosslinking or narrow molecular weight distribution. It can be adjusted to any storage modulus based on this tendency.

When laser light with a wavelength of 1064nm is used in invisible cutting, etc., the light transmittance of the substrate 41 at a wavelength of 1064nm after heating is preferably 40% or more and 100% or less, more preferably 50% or more and 99.9% or less, especially Preferably, it is 60% or more and 99.5% or less. By setting the light transmittance of the substrate 41 with a wavelength of 1064 nm after heating in the above-mentioned range, the work piece by invisible cutting can be separated well.

In addition, in the case of using laser light with a wavelength of 532nm to perform laser marking on the protective film, the light transmittance of the substrate 41 at a wavelength of 532nm after heating is preferably 0% or more and 40% or less, more preferably It is 0.01% or more and 35% or less, more preferably 0.05% or more and 30% or less. The light transmittance at a wavelength of 532 nm after heating of the substrate 41 is within the above range, so that the laser printability is excellent.

Specific examples of the resin film constituting the base material 41 include: Low-Density Polyethylene (LDPE) film, Linear Low-Density Polyethylene (LLDPE) film, High-density polyethylene (High-Density Polyethylene, HDPE) films such as polyethylene film, polypropylene film, ethylene/propylene copolymer film, polybutene film, polybutadiene film, polymethylpentene film, ethylene/norbornene copolymer Films, norbornene resin films and other polyolefin films; ethylene/vinyl acetate copolymer films, ethylene/(meth)acrylic acid copolymer films, ethylene/(meth)acrylate copolymer films and other ethylene copolymer films; Polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; polyester films such as polyethylene terephthalate film and polybutylene terephthalate film; polyurethane film; Polyimide film; polystyrene film; polycarbonate film; fluororesin film, etc. In addition, modified membranes such as these crosslinked membranes and ionomer membranes can also be used. Furthermore, it may be a laminated film formed by laminating a plurality of the above-mentioned films.

In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. Other similar terms are also the same.

Among the above, polyolefin-based films are preferred; polyethylene films, polypropylene films, and ethylene/propylene copolymer films are more preferred; and ethylene/propylene copolymer films are particularly preferred. These resin films can easily satisfy the aforementioned physical properties, especially in the case of ethylene/propylene copolymer films, by adjusting the copolymerization ratio of ethylene monomer and propylene monomer, the aforementioned physical properties can be easily satisfied. In addition, these resin films are also preferable from the viewpoint of work attachment property or wafer peelability.

In order to improve the adhesiveness of the above-mentioned resin film with the adhesive layer 42 laminated on the surface, surface treatment by oxidation or unevenness or primer treatment may be performed on one or both surfaces as necessary. Examples of the above-mentioned oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. In addition, as the roughening method, for example, a sandblasting method, a spraying method, etc. can be cited.

Furthermore, 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 above-mentioned resin film.

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

The so-called "thickness" is the value measured by the contact thickness meter at any 5 locations and expressed in average.

1-2. Adhesive layer

The adhesive layer 42 provided in the first support sheet 4 of the protective film forming sheet 3 of one embodiment of the present invention may be composed of an energy ray non-curable adhesive or may be composed of an energy ray curable adhesive. As an energy-ray non-curable adhesive, it is preferable to have the required adhesive strength and releasability. For example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives can be used Adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, an acrylic adhesive with high adhesion to the protective film forming film 1 is preferable.

On the other hand, the energy-ray curable adhesive decreases the adhesive force by energy-ray irradiation. Therefore, if an energy ray curable adhesive is used, when a workpiece or a processed object is to be separated from the first support sheet 4, it can be easily separated by irradiating energy ray.

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

When the adhesive layer 42 contains an energy-ray curable adhesive, the adhesive layer 42 in the protective film forming sheet 3 is preferably hardened. 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 of the material is hardened to form a protective film, The smoothness (macro) of the surface of the protective film in contact with the hardened portion of the adhesive layer 42 becomes higher, and it is excellent in aesthetics as a protective film for chips. In addition, if laser printing is performed on a protective film with high surface smoothness, the visibility of the printing improves.

The energy-ray curable adhesive constituting the adhesive layer 42 can be an adhesive mainly composed of a polymer with energy-ray curability; it can also be a polymer without energy-ray curability, and one selected from energy-ray curable A mixture of at least one component of the group consisting of polyfunctional monomers and oligomers is the main component of the adhesive.

Hereinafter, the case where the energy-ray curable adhesive is mainly composed of a polymer having energy-ray curability will be described.

In addition, the "main component" referred to here refers to the content of 60% by mass or more with respect to the total mass of the energy ray curable adhesive.

The energy-ray-curable polymer is preferably a (meth)acrylate (co)polymer (A) (hereinafter referred to as "Energy ray hardening polymer (A)"). The energy-ray-curable polymer (A) is preferably a (meth)acrylic copolymer (a1) having a functional group-containing monomer unit, and an unsaturated-containing copolymer having a substituent bonded to the functional group The base compound (a2) is reacted to obtain a polymer.

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

As the functional group-containing monomer in the structural unit derived from the above-mentioned functional group-containing monomer, it is preferable to have a polymerizable double bond in the molecule, as well as a hydroxyl group, an amino group, a substituted amino group, and an epoxy group Monomers with functional groups.

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

As the above-mentioned (meth)acrylate monomers, alkyl (meth)acrylates with a carbon number of 1 to 20 in the alkyl group, cycloalkyl (meth)acrylates with a carbon number of 3 to 11 in the alkyl group, Benzyl (meth)acrylate and the like. Among these, alkyl (meth)acrylates having an alkyl group of 1 to 18 carbon atoms are preferred. Examples include methyl (meth)acrylate, ethyl (meth)acrylate, and propylene (meth)acrylate. Ester, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.

The acrylic copolymer (a1) is based on the total mass of the acrylic copolymer (a1) and contains the functional group at a ratio of usually 3% to 100% by mass, preferably 5% to 40% by mass. The structural unit derived from the monomer, and contains the structural unit derived from the (meth)acrylate monomer or its derivative at a ratio of usually 0% to 97% by mass, preferably 60% to 95% by mass Become.

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

Furthermore, the total mass of the structural unit derived from the above-mentioned functional group-containing monomer and the structural unit derived from the (meth)acrylate monomer or its derivative does not exceed 100% by mass.

The acrylic copolymer (a1) can be obtained by copolymerizing the above-mentioned functional group-containing monomers with (meth)acrylate monomers or derivatives thereof by a conventional method, and can also be copolymerized in addition to these monomers Dimethacrylamide, vinyl formate, vinyl acetate, styrene, etc.

The acrylic copolymer (a1) having the above-mentioned functional group-containing monomer unit (that is, the structural unit derived from the functional group-containing monomer) and the unsaturated-containing copolymer having a substituent bonded to the functional group The radical compound (a2) reacts to obtain an energy ray hardening polymer (A).

The substituent of 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 , Carboxyl or aziridinyl (aziridinyl).

In addition, the unsaturated group-containing compound (a2) contains 1 to 5, preferably 1 to 2 energy ray polymerizable carbon-carbon double bonds per molecule. As specific examples of the unsaturated group-containing compound (a2), for example, 2-methacryloxyethyl isocyanate, m-isopropenyl isocyanate-α,α-dimethylbenzyl Ester, methacrylic isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; by diisocyanate compound or polyisocyanate compound and (meth)acrylic acid Acrylic monoisocyanate compound obtained by the reaction of hydroxyethyl; Acrylic monoisocyanate compound obtained by the reaction of a diisocyanate compound or polyisocyanate compound, a polyol compound and hydroxyethyl (meth)acrylate; Glycidyl meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate; or 2-vinyl-2-oxazoline, 2-isopropenyl- Alkenyl oxazoline compounds such as 2-oxazoline.

Among the above, 2-methacryloxyethyl isocyanate is preferred.

The unsaturated group-containing compound (a2) is based on 100 equivalents of the functional group-containing monomer of the above-mentioned acrylic copolymer (a1), and is usually 10 equivalents to 100 equivalents, preferably 20 equivalents to 95 equivalents Ratio use.

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

The weight average molecular weight of the energy ray hardening polymer (A) thus obtained is preferably 10,000 or more, more preferably 150,000 to 1.5 million, and particularly 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).

Even when the energy ray curable adhesive is mainly composed of a polymer having energy ray curability, the energy ray curable adhesive may further contain energy ray curable monomers and oligomers. At least one component (B).

As at least one component (B) selected from the group consisting of energy-ray curable monomers and oligomers, for example, esters of polyhydric alcohols and (meth)acrylic acid can be cited.

As the at least one component (B) selected from the group consisting of energy-ray curable monomers and oligomers, for example, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, etc. Monofunctional acrylic esters; trimethylolpropane tri(meth)acrylate, neopentylerythritol tri(meth)acrylate, neopentylerythritol tetra(meth)acrylate, dineopentaerythritol six (Meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, two Multifunctional acrylates such as hydroxymethyl tricyclodecane di(meth)acrylate; polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate, etc.

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

When at least one component (B) selected from the group consisting of energy-ray curable monomers and oligomers is formulated, the content of the component (B) in the energy-ray curable adhesive is relative to the aforementioned energy line The total mass of the hardening adhesive is preferably 5 mass% to 80 mass%, more preferably 20 mass% to 60 mass%.

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

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, and benzoin Methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone (2,4-diethylthioxanthone), 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethyl monosulfide Kethiuram, azobisisobutyronitrile, benzil, dibenzyl, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide, 2-Benzothiazole-N,N-diethyldithiocarbamate, oligomeric {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.

When the energy ray curable copolymer (A) (in the case of blending at least one component (B) selected from the group consisting of energy ray curable monomers and oligomers, the energy ray curable copolymer (A) and at least one component selected from the group consisting of energy-ray curable monomers and oligomers (B) is set to 100 parts by mass. When it is set to 100 parts by mass, the photopolymerization starts The agent (C) is preferably used in an amount in the range of 0.1 parts by mass to 10 parts by mass, especially 0.5 parts by mass to 6 parts by mass.

In the energy ray curable adhesive, other components may be appropriately formulated in addition to the above-mentioned components. As other components, for example, a polymer component or an oligomer component (D), a crosslinking agent (E), etc. which do not have energy ray curability can be cited.

That is, one form of the energy ray curable adhesive includes an energy ray curable copolymer (A) and optionally at least one component selected from the group consisting of energy ray curable monomers and oligomers ( B) At least one component selected from the group consisting of a photopolymerization initiator (C), a polymer component or oligomer component (D) without energy ray curability, and a crosslinking agent (E).

Examples of the polymer component or oligomer component (D) that does not have energy ray curability include polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, etc., and weight average A polymer or oligomer with a molecular weight (Mw) of 3,000 to 2.5 million.

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

By blending these other components (D) and (E) into the energy-ray curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesion to other layers, and the storage stability can be improved Wait. 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 with respect to 100 parts by mass of the energy ray curable copolymer (A).

Next, it is explained below that the energy-ray curable adhesive is a mixture of a polymer component that does not have energy-ray curability and at least one selected from the group consisting of energy-ray curable polyfunctional monomers and oligomers. The main component of the situation.

As a polymer component that does not have energy ray curability, for example, the same component as the aforementioned acrylic copolymer (a1) can be used. The content of the polymer component that does not have energy ray curable properties in the energy ray curable resin composition is preferably 20% by mass to 99.9% by mass relative to the total mass of the aforementioned energy ray curable resin composition, and more preferably 30% to 80% by mass.

As at least one component selected from the group consisting of energy-ray curable polyfunctional monomers and oligomers, the same as the aforementioned component (B) can be selected. The blending ratio of a polymer component that does not have energy ray hardenability and at least one component selected from the group consisting of energy ray hardenable polyfunctional monomers and oligomers will be a polymer that does not have energy ray hardenability When the component is 100 parts by mass, at least one component selected from the group consisting of multifunctional monomers and oligomers is preferably 10 parts by mass to 150 parts by mass, more preferably 25 parts by mass to 100 parts by mass.

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

That is, one form of the energy ray curable adhesive includes at least one component selected from the group consisting of a polymer component that does not have energy ray curability, a polyfunctional monomer and oligomer with energy ray curability, and Optionally, at least one component selected from the group consisting of a photopolymerization initiator (C) and a crosslinking agent (E).

The thickness of the adhesive layer 42 is not particularly limited as long as it can function appropriately in each step of using the protective film forming sheet 3. Specifically, it 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 a film for forming a protective film on a workpiece or a processed product obtained by processing the aforementioned workpiece. The protective film is composed of a cured protective film forming film 1. Examples of the workpiece include semiconductor wafers, and examples of the processed products obtained by processing the aforementioned workpiece include semiconductor wafers, but the present invention is not limited to these. Furthermore, when the workpiece is a semiconductor wafer, the protective film is formed on the back side of the semiconductor wafer (the side where the bumps and other electrodes are not formed).

The protective film forming film 1 may be a film including a single layer or a film including a plurality of layers. In terms of the ease of control of light transmittance and the manufacturing cost, it is preferable to include a single layer.

The protective film forming film 1 preferably contains a curable material, and as a specific example of such a material, an uncured curable adhesive can be cited. In this case, after the protective film forming film 1 is overlapped with a workpiece such as a semiconductor wafer, the protective film forming film 1 is cured, thereby allowing the protective film composed of the cured protective film forming film 1 to be firmly attached to the workpiece, and A durable protective film can be formed on a wafer or the like.

That is, one aspect of the protective film forming sheet of one embodiment of the present invention includes a protective film forming film formed of an uncured curable material.

The protective film forming film 1 preferably has adhesiveness at normal temperature, or exhibits adhesiveness by heating. Thereby, when the protective film formation film 1 overlaps with the workpiece|work, such as a semiconductor wafer, as mentioned above, both can be bonded. Therefore, it is possible to reliably perform positioning before curing the protective film forming film 1.

The curable adhesive constituting the protective film forming film 1 having such 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 of these can be used, and it is particularly 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, and benzoxazines. Resins, etc. and their mixtures. Among them, epoxy resins, phenol resins, and mixtures of these can be preferably used.

Epoxy resin has the property of being heated to form a three-dimensional network to form a strong film. As such an epoxy resin, conventionally known various epoxy resins can be used, and generally the molecular weight (formula weight) is preferably about 300 to 2000, and the molecular weight is more preferably 300 to 500. It is more preferable to blend an epoxy resin with a molecular weight of 330 to 400 that is liquid at room temperature, and an epoxy resin with a molecular weight of 400 to 2500, especially 500 to 2000, which is solid at room temperature. In addition, the epoxy equivalent of the epoxy resin is preferably 50 g/eq to 5000 g/eq.

As such epoxy resins, specifically, glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; butylene glycol, polyethylene Glycidyl ethers of alcohols such as glycols and polypropylene glycols; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid and tetrahydrophthalic acid; aniline isocyanurate, etc. bonded to nitrogen atoms Glycidyl or alkyl glycidyl epoxy resin with active hydrogen substituted by glycidyl; vinyl cyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexyl Alkyl carboxylate, 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, etc., by making the carbon in the molecule- The carbon double bond is oxidized, for example, to introduce a so-called alicyclic epoxide with an epoxy group. In addition, epoxy resins having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, etc. may also be used.

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

When an epoxy resin is used, it is preferable to use a thermoactive latent epoxy resin hardener as an auxiliary agent. The so-called "thermally active latent epoxy resin hardener" is a type of hardener that does not react with epoxy resin at room temperature, but is activated by heating above a certain temperature and reacts with epoxy resin. The activation method of the thermally active latent epoxy resin hardener is: the method of generating active substances (anions, cations) by the chemical reaction of heating; stably dispersed in the epoxy resin near room temperature, and at high temperature The method of dissolving and dissolving with epoxy resin to start the hardening reaction; the method of using molecular sieve-enclosed hardener to dissolve at high temperature to start the hardening reaction; the method of using microcapsules.

Specific examples of thermally active latent epoxy resin hardeners include various onium salts, or dibasic acid dihydrazine compounds, dicyandiamine, amine adduct hardeners, imidazole compounds and other high melting point active hydrogens. Compound etc. These thermally active latent epoxy resin hardeners may be used alone or in combination of two or more kinds. The 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 more preferably 0.3 parts by weight relative to 100 parts by weight of epoxy resin Use in the ratio of parts to 5 parts by weight.

As the phenol resin, condensation products of phenols and aldehydes, such as alkylphenols, polyphenols, and naphthols, can be used without particular limitation. Specifically, phenol novolak resin, ortho-cresol novolak resin, p-cresol novolak resin, tertiary butylphenol novolak resin, dicyclopentadiene cresol resin, poly(p-vinylphenol) resin, Bisphenol A-type novolac resins, or these modified products, etc.

The phenolic hydroxyl group contained in these phenolic resins easily undergo an addition reaction with the epoxy group of the epoxy resin by heating, and can form a cured product with high impact resistance. Therefore, an epoxy resin and a phenol resin can also be used together.

As the energy ray curable component, at least one component (B) selected from the group consisting of energy ray curable polymers in the adhesive layer 42 or energy ray curable monomers and oligomers can be cited Listed ingredients.

The binder polymer component imparts moderate viscosity to the protective film forming film 1 and can improve the handling of the protective film forming sheet 3. The weight average molecular weight of the binder polymer is usually in the range of 50,000 to 2 million, preferably 100,000 to 1.5 million, and particularly preferably 200,000 to 1 million. If the weight average molecular weight is too low, the film formation of the protective film forming film 1 will become insufficient, and if it is too high, the compatibility with other components will deteriorate, and as a result, uniform film formation will be hindered. That is, if the weight average molecular weight is more than the above lower limit, the film formation of the protective film forming film 1 is sufficient, and if it is less than the above upper limit, the compatibility with other components is good, and as a result, a uniform film can be formed. As such a binder polymer, for example, acrylic polymers, polyester resins, phenoxy resins, urethane resins, silicone resins, rubber polymers, etc. can be used, and acrylic polymers can be used particularly preferably. polymer.

Examples of acrylic polymers include (meth)acrylate copolymers containing (meth)acrylate monomers and structural units derived from (meth)acrylic acid derivatives. Here, as the (meth)acrylate monomers, alkyl (meth)acrylates having an alkyl group of 1 to 18 carbon atoms can be preferably cited, specifically, methyl (meth)acrylate, Ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, etc. In addition, examples of (meth)acrylic acid derivatives include (meth)acrylic acid, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

In the above, if glycidyl methacrylate or the like is used as a structural unit and a glycidyl group is introduced into an acrylic polymer, the compatibility with the epoxy resin as the thermosetting component is improved, and the protective film forming film 1 is cured Afterwards, the glass transition temperature (Tg) becomes higher and the heat resistance improves. In addition, in the above, if hydroxyethyl acrylate or the like is used as a structural unit and a hydroxyl group is introduced into the acrylic polymer, it is possible to control the adhesion to the workpiece or the adhesion properties.

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, and particularly preferably 150,000 to 1 million. The glass transition temperature of acrylic polymer is usually below 20°C, preferably around -70°C to 0°C, and has adhesiveness at normal temperature (23°C).

Regarding the blending ratio of the thermosetting component and the binder polymer component, when the binder polymer component is set to 100 parts by weight, the blending amount of the thermosetting component is preferably 50 parts by weight to 1500 parts by weight, more preferably 70 parts by weight to 1000 parts by weight, particularly preferably 80 parts by weight to 800 parts by weight. If the thermosetting component and the adhesive polymer component are blended at such a ratio, it will show a moderate viscosity before curing, can stably perform the sticking operation, and obtain a protective film with excellent film strength after curing.

The protective film forming film 1 may further contain at least one component selected from the group consisting of a colorant and a filler.

As the coloring agent, for example, well-known coloring agents such as inorganic pigments, organic pigments, and organic dyes can be used. From the viewpoint of improving the controllability of light transmittance, the coloring agent preferably contains an organic coloring agent. From the viewpoint of improving the chemical stability of the coloring agent (specifically, the properties of hardly eluted, hard to cause color shift, and little change over time), the coloring agent is preferably a coloring agent containing a pigment.

Examples of the filler include silica such as crystalline silica, fused silica, and synthetic silica, or inorganic fillers such as alumina and glass balls. Among them, silicon dioxide is preferable, and synthetic silicon dioxide is more preferable, and particularly preferable is a type of synthetic silicon dioxide that removes as much as possible the line source of the alpha line which is the main cause of the malfunction of the semiconductor device. As the shape of the filler, spherical, needle-like, amorphous, etc. can be cited, and spherical is preferred, and spherical is particularly preferred. If the filler is spherical or spherical, it is not easy to produce diffuse reflection of light, and it is easy to control the light transmittance spectrum of the protective film forming film 1.

The content of at least one component selected from the group consisting of colorants and fillers is preferably 5% by mass to 75% by mass relative to the mass of the entire protective film forming film.

The average particle size of the filler is preferably 0.005 μm to 20 μm.

In addition, the protective film forming film 1 may contain a coupling agent. By containing the coupling agent, after the curing of the protective film forming film 1, the heat resistance of the protective film will not be impaired, and the adhesion and adhesion between the protective film and the workpiece can be improved, and the water resistance (resistant Humidity) improves. As the coupling agent, a silane coupling agent is preferred in terms of its versatility and cost advantage.

As the silane coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl) Ethyl trimethoxysilane, γ-(methacryloxypropyl) trimethoxysilane, γ-aminopropyl trimethoxysilane, N-6-(aminoethyl)-γ-amino Propyl trimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyl diethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ- Ureapropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl) tetrasulfide, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, imidazolesilane, etc. Among them, γ-glycidoxypropyltrimethoxysilane is preferred. These can be used individually by 1 type, or in mixture of 2 or more types.

In the case where the protective film forming film 1 contains a binder polymer component and a curable component, when the total mass parts of the binder polymer component and the curable component is 100 parts by mass, the content of the coupling agent is preferably 0.1 Parts by mass ~ 5 parts by mass.

In order to adjust the cohesive force before curing, the protective film forming film 1 may also contain a crosslinking agent such as an organic polyisocyanate compound, an organic polyimine compound, and an organic metal chelate compound. In addition, in order to suppress static electricity and improve the reliability of the wafer, the protective film forming film 1 may contain an antistatic agent. In addition, in order to improve the flame retardancy of the protective film and improve the reliability as a package, the protective film forming film 1 may also contain flame retardants such as phosphoric acid compounds, bromine compounds, and phosphorus compounds.

That is, one form of the protective film forming film 1 includes a curable component, a binder polymer component, and optionally at least one component selected from the group consisting of a colorant and a filler, a coupling agent, a crosslinking agent, At least one component selected from the group consisting of antistatic agents and flame retardants.

In order to effectively perform the 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 particularly preferably 7 μm to 100 μm.

3. Protective film

The protective film formed by the protective film forming film 1 of one embodiment of the present invention has the following characteristics.

The breaking strain of the protective film at 50°C is 0.1% or more and 20% or less. By setting the breaking strain to 20% or less, when the first support sheet 4 is stretched (stretched) under the conditions described below, the protective film included in the first support sheet 4 can be appropriately divided. If the breaking strain at 50°C exceeds 20%, the division of the protective film is likely to become inappropriate. Specifically, the material forming the protective film is likely to be partially filamentous in the divided part without being divided (referred to in this specification) Is the "drawing phenomenon"). From the viewpoint of achieving proper division of the protective film more stably, the breaking strain at 50°C of the protective film is preferably 0.2% or more and 15% or less, more preferably 0.3% or more and 13% or less, and particularly preferably 0.5% Above and below 10%.

The breaking stress of the protective film at 50°C is 1.0×10 ³ Pa or more and 2.0×10 ⁷ Pa or less. By setting the breaking stress to 2.0×10 ⁷ Pa or less, when the first support sheet 4 is extended (stretched) under the conditions described below, the protective film provided in the first support sheet 4 can be appropriately divided. From the viewpoint of achieving the proper division of the protective film more stably, the breaking stress at 50°C of the protective film is preferably 5.0×10 ³ Pa or more and 1.9×10 ⁷ Pa or less, more preferably 8.0×10 ³ Pa or more and 1.8×10 ⁷ Pa or less, particularly preferably 1.0×10 ⁴ Pa or more and 1.7×10 ⁷ Pa or less.

In addition, the "breaking strain at 50°C" and the "breaking stress at 50°C" of the protective film can be measured by the method described in the test example described later.

The storage modulus of the protective film at 25°C is preferably 3.0×10 ⁹ Pa or more and 5.0×10 ¹¹ Pa or less, and more preferably 5.0×10 ⁹ Pa or more and 1.0×10 ¹¹ Pa or less. By setting the storage modulus of the protective film at 25° C. to be 3.0×10 ⁹ Pa or more, when the semiconductor chip with the protective film is separated from the first support sheet 4, it is not easy to cause defects in the protective film.

The loss tangent of the protective film at 25°C is preferably 0.01 or more and 0.4 or less. By setting the loss tangent of the protective film at 25°C to 0.4 or less, when the semiconductor chip with the protective film is separated from the first support sheet 4, the defect of the protective film is less likely to occur. The loss tangent of the protective film at 25°C is more preferably 0.03 or more and 0.3 or less, and particularly preferably 0.05 or more and 0.2 or less.

Furthermore, the "storage modulus at 25°C" and the "loss tangent at 25°C" of the protective film can be measured by the method described in the test example described later.

The light transmittance of the protective film with a wavelength of 1064 nm is preferably 40% or more and 100% or less. By making the light transmittance of the protective film with a wavelength of 1064nm above 40%, the laser light used for invisible cutting can efficiently reach the semiconductor wafer and other workpieces. From the viewpoint of stably allowing the laser light to reach the semiconductor wafer efficiently, the light transmittance of the protective film having a wavelength of 1064 nm is preferably 50% or more and 99.9% or less, more preferably 60% or more and 99.5% or less.

The peak temperature T1 of the loss tangent of the protective film is in the range of 25°C to 60°C. By keeping the peak temperature T1 of the loss tangent within the above-mentioned range, under the conditions described below (specifically, the temperature of the protective film when the first support sheet 4 is stretched in the first division step is kept within the range of 40°C to 70°C) When the first support sheet 4 is extended (stretched) downward, the protective film included in the first support sheet 4 can be appropriately divided. When the temperature T1 is too low, the protective film will soften, and the breaking strain of the protective film at 50°C will easily exceed 20%. When the temperature T1 is too high, the protective film hardens, and it is difficult to properly divide the protective film when the first support sheet 4 is stretched. From the viewpoint of achieving the proper division of the protective film more stably, the temperature of the protective film when the first support sheet 4 is extended in the first division step is preferably equal to or higher than the peak temperature T1 of the loss tangent.

Furthermore, the "peak temperature of loss tangent" of the protective film can be measured by the method described in the test example described later.

That is, one form of the protective film forming sheet of the present invention has the aforementioned protective film forming film, and the aforementioned protective film forming film has the following characteristics: breaking strain at 50°C of 0.2% to 20%, and breaking at 50°C The stress is 5.0×10 ³ Pa or more and 2.0×10 ⁷ Pa or less.

The aforementioned protective film forming film may further have at least one of the following characteristics: the storage modulus at 25°C is 3.0×10 ⁹ Pa or more and 5.0×10 ¹¹ Pa or less; the loss tangent at 25°C is 0.01 or more and 0.4 or less; and the wavelength is 1064nm The light transmittance is above 40% and below 100%; the peak temperature T1 of the loss tangent is in the range of 25℃ to 60℃.

Furthermore, the so-called "characteristics" here refer to the chemical properties or physicochemical properties of the protective film forming film.

4. Adhesive layer for jig

As the adhesive constituting the adhesive layer 5 for jigs, an adhesive having the required adhesive force and releasability is preferable. For example, acrylic adhesives, rubber-based adhesives, silicone-based adhesives, Urethane-based adhesives, polyester-based adhesives, polyvinyl ether-based adhesives, etc. Among these, it is preferable that the adhesiveness with a jig such as a ring frame is high, and it is an acrylic adhesive that can effectively prevent the protective film forming sheet 3 from peeling off the ring frame or the like in a cutting step or the like. Furthermore, it can also be used as a base material of the core material interposed in the thickness direction of the jig adhesive layer 5.

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

In addition, the "thickness of the adhesive layer for jigs" refers to a value obtained by measuring the thickness at any 5 locations in a cut surface arbitrarily cut in the thickness direction and expressing it as an average.

5. Peel off sheet

The peeling sheet 6 of the protective film forming sheet 3 of one embodiment of the present invention protects the protective film forming film 1 and the adhesive layer 5 for jigs until the protective film forming sheet 3 is used.

The configuration of the release sheet 6 is arbitrary, and a sheet obtained by peeling a plastic film with a release agent or the like can be exemplified. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and polyolefin films such as polypropylene or polyethylene. . As the release agent, a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, etc. can be used. Among these, a silicone-based release agent that is inexpensive and can obtain stable performance is preferred. The thickness of the release sheet 6 is not particularly limited, but is usually about 20 μm to 250 μm.

6. Manufacturing method of protective film forming sheet

The sheet 3 for forming a protective film is preferably made of a laminate including the protective film forming film 1 (referred to as "layer 1" in this specification) and a layer including the first support sheet 4 (referred to as "laminate 1" in this specification). After the body II"), the layered body I and the layered body II are used to laminate the protective film forming film 1 and the first support sheet 4, but the manufacturing is not limited to this.

When manufacturing the laminated body I, the protective film formation film 1 is formed on the peeling surface of the 1st peeling sheet. Specifically, a coating agent for a protective film forming film containing a curable adhesive constituting the protective film forming film 1 and a solvent further containing a coating agent for the protective film forming film is prepared using a roll coater, a knife coater, and a roll knife Coater, air knife coater, die coater, bar coater, gravure coater, curtain coater and other coating machines, apply the aforementioned on the release surface of the first release sheet The coating agent is applied and dried to form the protective film forming film 1 on the release surface of the first release sheet. Next, the peeling surface of the second peeling sheet is superimposed on the exposed surface of the protective film forming film 1 and pressure-bonded to obtain a laminate (layered product I) in which the protective film forming film 1 is sandwiched by two peeling sheets.

The layered body I may be subjected to a half cut as necessary to make the protective film forming film 1 (and the second release sheet) into a desired shape, such as a circular shape. In this case, the excess parts of the protective film forming film 1 and the second release sheet generated by the half-cutting may be appropriately removed.

On the other hand, when the laminated body II is produced, the release surface of the third release sheet is coated with an adhesive that constitutes the adhesive layer 42 and, if necessary, a coating agent for the adhesive layer that further contains a solvent. After drying, the adhesive layer 42 is formed on the release surface of the third release sheet. After that, the substrate 41 is pressure-bonded to the exposed surface of the adhesive layer 42 to obtain a laminate (layered product II) including the first support sheet 4 including the substrate 41 and the adhesive layer 42 and the third release sheet.

Here, when the adhesive layer 42 contains an energy-ray curable adhesive, the adhesive layer 42 may be irradiated with energy rays at this stage to harden the adhesive layer 42, or the energy ray may be irradiated after the laminated protective film is formed to form the film 1. The adhesive layer 42 is hardened. In addition, when the adhesive layer 42 is hardened after the protective film is laminated to form the film 1, the adhesive layer 42 may be hardened before the cutting step, or the adhesive layer 42 may be hardened after the cutting step.

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

After the laminate I and the laminate II are obtained in this way, the second release sheet in the laminate I is peeled off, and the third release sheet in the laminate II is peeled, and the protective film forming film 1 and the laminate are exposed from the laminate I The adhesive layer 42 of the first supporting sheet 4 exposed by II is overlapped and crimped. The first supporting sheet 4 can also be half-cut as needed to become a desired shape, such as a circle having a larger diameter than the protective film forming film 1. In this case, the excess part of the first support sheet 4 produced by half-cutting can be appropriately removed.

Thus, a protective film forming sheet 3 is obtained, which includes: a first support sheet 4 formed by laminating an adhesive layer 42 on a base material 41; and a protective film forming film 1 formed by laminating an adhesive layer on the first support sheet 4 The side of the adhesive layer 42; and the first release sheet, which is laminated in the protective film forming film 1 and the surface facing the first support sheet 4 on the opposite side. Finally, after the first release sheet is peeled off, the surface of the protective film forming film 1 opposite to the surface facing the first support sheet 4 is formed on the peripheral edge portion of the surface opposite to the surface facing the first support sheet 4 to form the jig adhesive layer 5. The adhesive layer 5 for jigs can also be formed by applying the same method as the adhesive layer 42 described above.

7. How to use the protective film forming sheet

Hereinafter, as an example, a method of manufacturing a protective film-attached wafer from a semiconductor wafer as a workpiece using the protective film forming sheet 3 according to an embodiment of the present invention will be described.

(1) The first attachment step

First, the surface of the protective film forming film 1 included in the protective film forming sheet 3 of the one embodiment of the present invention that is opposite to the surface facing the first support sheet 4 is exposed. The protective film forming sheet 3 shown in FIG. 1 is as shown in FIG. 2, and the release sheet 6 may be peeled off.

Next, the exposed surface is attached to one surface of the semiconductor wafer 7 as a work, specifically to the surface (back surface) opposite to the circuit formation surface, to obtain a protective film forming sheet 3 and The first laminate 10 of the work 1 (FIG. 3). The first laminated body 10 shown in FIG. 3 further includes an adhesive layer 5 for jigs and a ring frame 8. As mentioned above, the adhesive layer 5 for jigs is an essential element of the protective film forming sheet 3. In the first attaching step, the protective film forming film 1 of the protective film forming sheet 3 is attached to the semiconductor crystal. In the case of circle 7, the jig adhesive layer 5 of the protective film forming sheet 3 may be attached to the ring frame 8.

That is, one aspect of the first attaching step includes exposing the surface of the protective film forming film included in the protective film forming sheet of one embodiment of the present invention that is opposite to the surface facing the first support sheet; and The exposed surface is attached to one surface of the workpiece to obtain a first laminate including the sheet for forming a protective film and the workpiece.

(2) The first curing step

The protective film forming film 1 included in the protective film forming sheet 3 of the first laminate 10 obtained by the first bonding step is cured to obtain a protective film. The curing conditions for obtaining the protective film are appropriately set according to the material constituting the protective film forming film 1. When the protective film forming film 1 is a thermosetting adhesive, the protective film forming film 1 may be heated at a specific temperature for an appropriate time. In addition, when the protective film forming film 1 is not a thermosetting adhesive, heat treatment is separately performed.

That is, one aspect of the first curing step includes obtaining a protective film by curing the protective film forming film in the first laminate.

The heating time and the heating temperature vary according to the material constituting the film, and it is preferably, for example, heating at 90°C to 170°C for 0.5 hour to 5 hours.

(3) The first division step

The temperature of the protective film included in the protective film forming sheet 3 of the first laminate 10 after the first curing step is maintained in the range of 40°C to 70°C, and the protective film forming sheet 3 The provided first support sheet 4 is extended (stretched), and the protective film is divided together with the semiconductor wafer 7. As a result, as shown in FIG. 4, a second laminated body 20 is obtained. The laminated body of the semiconductor wafer 7 and the protective film is arranged on one surface of the first support sheet 4 to be divided so as to produce a cut surface in the thickness direction. A plurality of (for example, 2~20,000) chips 9 with protective film.

That is, one aspect of the first dividing step includes: maintaining the temperature of the protective film in the first laminate after the first curing step in the range of 40°C to 70°C, and making the first support The sheet is stretched, and the laminate of the work and the protective film is divided, thereby obtaining a second laminate in which a plurality of wafers with protective films are arranged on one surface of the first support sheet.

The method of extending the first support sheet 4 is not limited. As shown in FIG. 4, the ring-shaped member R can be pressed from the side of the first support piece 4 opposite to the surface facing the ring frame 8, and the ring frame 8 and the ring-shaped member R can be made of lead The relative position in the vertical direction changes, thereby extending the first support piece 4. That is, the stress generated in the support sheet 4 by the aforementioned elongation includes a vector in the horizontal direction or a direction parallel to the back surface of the semiconductor wafer 7.

Generally, when the first supporting sheet 4 is extended, the member located between the first supporting sheet 4 and the semiconductor wafer 7 is the protective film forming film 1. The protective film forming film 1 is generally composed of a material that can form a protective film by curing, that is, a curable material, and a typical example thereof is an uncured curable adhesive. When such a material is given a tensile force, the amount of deformation (breaking strain) before breaking is large, and the first support sheet 4 may be stretched (stretched) without being divided. Therefore, when the first support sheet 4 is stretched, the protective film forming film 1 is cooled to about 0°C to -20°C (specifically, it is usually achieved by cooling the first layered body 10). The breaking strain of the protective film forming film 1 is reduced. However, generally compared with heating, cooling requires relatively expensive cooling equipment, and the energy required for cooling is greater than that for heating. Therefore, cooling the protective film forming film 1 usually means cooling the first layered body 10, which increases the initial investment and operating costs in the method of manufacturing a wafer with a protective film.

In contrast, in the method of manufacturing a chip with a protective film according to an embodiment of the present invention, when the first support sheet 4 is extended, the member located between the first support sheet 4 and the semiconductor wafer 7 is a protective film. Since the protective film is obtained by curing the protective film forming film 1, its breaking strain is lower than that of the protective film forming film 1. Therefore, it is not easy to produce segmentation failure due to fracture strain. However, since the protective film is a hardened material, the fracture stress may increase, and there may be a possibility of poor segmentation due to the high fracture stress. Therefore, in the method of manufacturing a wafer with a protective film according to an embodiment of the present invention, when the first support sheet 4 is stretched, the temperature of the protective film is maintained in the range of 40°C to 70°C.

That is, by performing hot stretching in contrast to the conventional cold stretching, the possibility of defective division of the protective film is reduced. If the protective film is heated to about 40°C, the fracture stress decreases significantly compared to the room temperature (23°C) state, and the effect due to thermal extension (reduction of poor division) can be stably obtained. On the other hand, if the temperature of the protective film during the stretching of the first support sheet 4 exceeds 70°C, the breaking strain of the protective film increases, and the mechanical properties of the first support sheet 4 change (the Young’s modulus decreases and the softening Etc.) The possibility of malfunctions (specific examples, such as the decrease of the extension amount, the fusion of the first support sheet 4 to the stage, etc.) caused by the operation becomes obvious. Therefore, by setting the temperature of the protective film when the first support sheet 4 is stretched to 70° C. or lower, the possibility of defects in the production of the protective film-attached chip can be stably reduced. From the viewpoint of reducing the possibility of such failures more stably, the temperature of the protective film during the stretching of the first support sheet 4 is preferably 42°C or higher and 65°C or lower, and more preferably 43°C or higher and 60°C or lower, particularly preferably 45°C or higher and 55°C or lower.

(4) The first picking step

In the first pick-up step, the plurality of protective film-attached wafers 9 included in the second laminate 20 obtained by performing the first division step are separated from the first support sheet 4 to obtain individual protected wafers. The film wafer 9 is used as a processed object. The separation method is not limited. As shown in Figure 5, the jacking pin P and the vacuum suction collet C can be used. In this way, a chip 9 with a protective film can be obtained.

That is, one form of the first pickup step includes obtaining the protective film-attached wafers by separating the plurality of protective film-attached wafers included in the second laminate from the first support sheet, respectively. Processed objects.

(5) Steps for forming modified layer

Before starting the first dividing step, a reforming layer forming step is performed. The laser light in the infrared region (for example, 1064nm) is irradiated to the focal point set in the semiconductor wafer 7 (workpiece). 7 A modified layer is formed inside. In the first division step, the semiconductor wafer 7 is divided at the planned division line by extending the first support sheet bonded to the semiconductor wafer 7 after the reforming layer forming step.

That is, one aspect of the reforming layer forming step includes irradiating laser light in the infrared region to focus on the focal point set inside the workpiece before starting the first dividing step, and forming the reforming layer inside the workpiece.

8. Other embodiments of the protective film forming sheet

(1) When the first support sheet does not have an adhesive layer for jigs

Fig. 6 is a cross-sectional view of a protective film forming sheet according to another embodiment of the present invention. As shown in FIG. 6, the protective film forming sheet 3A of the present embodiment is configured to include: a first support sheet 4 formed by layering an adhesive layer 42 on one area of a base material 41; and a protective film forming film 1, which is laminated The side where the adhesive layer 42 is laminated in the first support sheet 4; and the release sheet 6, which is laminated in the protective film forming film 1 on the opposite side to the surface facing the first support sheet 4. The protective film forming film 1 in the embodiment is formed so as to be substantially the same as or slightly larger than the workpiece in the surface direction, and is formed so as to be smaller than the first support sheet 4 in the surface direction. The adhesive layer 42 in the portion where the protective film forming film 1 is not laminated can be attached to a jig such as a ring frame.

The material and thickness of each member of the protective film forming sheet 3A of this embodiment are the same as the material and thickness of each member of the protective film forming sheet 3 described above. However, when the adhesive layer 42 contains an energy-ray-curable adhesive, it is preferable to harden the energy-ray-curable adhesive in the part of the adhesive layer 42 to be in contact with the protective film forming film 1, and the other parts are not Harden the energy ray curable adhesive. Thereby, the smoothness (macro) of the protective film formed by curing the protective film forming film 1 can be improved, and the adhesive force to jigs such as a ring frame can be maintained high.

Furthermore, in the adhesive layer 42 of the first support sheet 4 of the protective film forming sheet 3A, the peripheral edge portion opposite to the base material 41 may be separately provided with an adhesive for jigs with the aforementioned protective film forming sheet 3 Adhesive layer for jigs with the same agent layer 5.

(2) When the first support sheet does not have an adhesive layer

As shown in FIG. 11, the 1st support sheet with which the sheet 3B for protective film formation which is one of other embodiments of the present invention is equipped may not have an adhesive layer, and may consist of a base material (only). In this case, the surface of the base material on the side where the protective film is formed corresponds to the first surface of the first support sheet.

When the first support sheet is composed of a base material, it is preferable that the peripheral part of the surface opposite to the surface facing the base material (the first support sheet) in the protective film formation film is provided with the treatment shown in FIG. The adhesive layer for jigs is the same as the adhesive layer 5 for jigs.

(3) When the first support sheet is a release sheet

The first support sheet provided in the protective film forming sheet of one of the other embodiments of the present invention may be a release sheet having a release surface. In this case, the peeling surface corresponds to the first surface of the first support sheet. The specific structure of the release sheet is not limited.

(4) With the second support sheet

The sheet for forming a protective film according to another embodiment of the present invention may include a second supporting sheet, which is laminated on the side of the protective film forming film opposite to the surface facing the first supporting sheet. The second support sheet may be a peeling sheet, and is arranged such that the peeling surface faces the protective film forming film.

(5) When the first support sheet is peeled from the protective film forming film

As shown in FIGS. 2 to 5, in the manufacturing method of the protective film-attached wafer 9 of one embodiment of the present invention, after the protective film is formed from the protective film forming film 1 in the first curing step, it is picked up in the first In the step, the protective film is separated from the first support sheet 4, specifically, the division of the protective film that is a part of the protective film-attached wafer 9 is separated.

In the manufacturing method of a wafer with a protective film which is one of the other embodiments of the present invention, the protective film forming film is peeled from the first support sheet and then cured to become a protective film. An example of such a manufacturing method is as follows.

That is, one mode of the manufacturing method of the present embodiment is shown in FIGS. 7 to 10, and includes a layering step of making the protective film forming film 1 included in the protective film forming sheet of one embodiment of the present invention and the surface The surface of the first support sheet is exposed on the opposite side, the exposed surface is attached to one surface of the workpiece 7 such as a semiconductor wafer, and the first support sheet of the protective film forming sheet is peeled from the protective film forming film , Thereby obtaining a third layered body 11 having the workpiece 7 and the protective film forming film 1; the second curing step is to harden the protective film forming film of the third layered body 11 to obtain a protective film ; The second attaching step is to include the third substrate 132 and the third adhesive layer 131 laminated on one surface side of the third substrate in the processing sheet 13 on the surface of the third adhesive layer side 131, It is bonded to the surface of the protective film side of the third laminate 11 that has undergone the second curing step, thereby obtaining a fourth laminate 12 having the processing sheet 13 and the third laminate 11; The dividing step is to extend the processing sheet 13 included in the fourth laminate 12 while maintaining the temperature of the protective film included in the fourth laminate 12 in the range of 40°C to 70°C. The protective film is divided together with the work 7 to obtain a fifth laminate 14. The fifth laminate 14 is arranged on one surface of the processing sheet 13 with a laminate of the work 7 and the protective film. A plurality of (for example, 2 to 20,000) wafers 9 with a protective film, which are divided into a cut surface in the thickness direction; and the second pick-up step, is to attach the plurality of chips of the fifth laminate 14 with The protective film wafers 9 are respectively separated from the aforementioned processing sheet 13 to obtain the protective film-attached wafer 9 as a processed product; and further include a modified layer forming step, which is started from the second dividing step Previously, laser light in the infrared region was irradiated to focus on the focal point set inside the workpiece 7 to form a modified layer inside the workpiece 7.

Here, the third base 132 included in the processing sheet 13 may have the same characteristics as the base 41 included in the support sheet 4. In addition, the third adhesive layer 131 included in the processing sheet 13 may have the same characteristics as the adhesive layer 42 included in the support sheet 4.

In addition, the temperature of the protective film included in the fourth laminate 12 in the second dividing step is preferably the temperature T1 or higher.

The embodiments described above are described in order to facilitate the understanding of the present invention, and do not limit the present invention. Therefore, the requirements disclosed in the above-mentioned embodiments also include all design changes or equivalents belonging to the technical scope of the present invention.

For example, another layer may be interposed between the base material 41 and the adhesive layer 42 in the first support sheet 4. In addition, other layers of the first area layer of the first support sheet 4 including the base material 41 may be used. As other layers, for example, a layer for adjusting the adhesiveness between the base material 41 and the adhesive layer 42 such as a primer layer, and a layer for adjusting the adhesiveness between the support sheet 4 and the protective film forming film 1 can be cited.

The aforementioned method for manufacturing a wafer with a protective film can also use a protective film forming film other than the protective film forming film of the embodiment of the present invention.

That is, another aspect of the method of manufacturing a wafer with a protective film as an embodiment of the present invention includes: an attaching step of including a first support sheet and layering on the first surface side of the first support sheet In the protective film forming sheet of the protective film forming film (the protective film forming film other than the protective film forming film of the embodiment of the present invention), the surface of the protective film forming film is opposite to the surface facing the first support sheet The surface is exposed, and the exposed surface is attached to one surface of the workpiece to obtain a first laminate including the protective film forming sheet and the workpiece; the first curing step is to make the protective film in the first laminate The formed film is cured to obtain a protective film; the first division step is to maintain the temperature of the protective film in the first laminate after the first curing step in the range of 40°C to 70°C, and make the The first support sheet is stretched, and the protective film is divided together with the work to obtain a second laminate. The second laminate system is provided with a laminate of the work and the protective film on one surface of the first support sheet A plurality of protective film-attached wafers divided in such a way that a cut surface is generated in the thickness direction; and the first pick-up step is to separate the plurality of protective film-attached wafers provided in the second laminate from the foregoing The first support sheet is separated to obtain the aforementioned wafer with a protective film as a processed object; and further includes a modified layer forming step, which is before the start of the first dividing step to focus on the setting The focal point inside the workpiece irradiates laser light in the infrared region to form a modified layer inside the workpiece.

In addition, it is preferable that the temperature of the protective film provided in the first laminate in the first dividing step is the temperature T1 or higher.

In addition, another aspect of the method of manufacturing a wafer with a protective film, which is an embodiment of the present invention, includes a lamination step including a first support sheet and a protective film laminated on the first surface of the first support sheet In the protective film forming sheet of the protective film forming film (the protective film forming film other than the protective film forming film of the embodiment of the present invention), the surface of the protective film forming film opposite to the surface facing the first support sheet is exposed, Attach the exposed surface to one surface of the workpiece, and peel off the first support sheet from the protective film forming film, thereby obtaining a third laminate having the workpiece and the protective film forming film; a second curing step, The protective film is obtained by curing the protective film forming film of the third layered body; the second attaching step is to attach the third substrate with the third substrate and the third layer laminated on one side of the third substrate The surface on the side of the third adhesive layer laminated in the processing sheet of the agent layer and the surface on the protective film side of the third laminate after the second curing step are bonded together to obtain the processing Sheet and the fourth layered body of the third layered body; the second dividing step is to maintain the temperature of the protective film of the fourth layered body in the range of 40°C to 70°C, and make the fourth layer The processing sheet of the laminated body is stretched, and the protective film is divided together with the workpiece to obtain a fifth laminated body. The fifth laminated system is provided with the workpiece and the protective film on one side of the processing sheet The laminated body is divided into a plurality of protective film-attached wafers in a manner that produces a cut surface in the thickness direction; and the second picking step is to combine the plurality of protective film-attached wafers provided in the fifth laminated body Separate from the processing sheet to obtain a wafer with a protective film as a processed product; and further include a modified layer forming step, which is before the start of the second dividing step to focus on the setting The focal point inside the workpiece irradiates laser light in the infrared region to form a modified layer inside the workpiece.

In addition, it is preferable that the temperature of the protective film included in the fourth laminate in the second dividing step is the temperature T1 or higher.

(Example)

Hereinafter, the present invention will be explained in more detail with examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

The following ingredients were mixed at the blending ratio (in terms of solid content) shown in Table 1, and methyl ethyl was used so that the solid content concentration was 50% by mass relative to the total mass of the coating agent for forming a protective film. The base ketone is diluted to prepare a coating agent for forming a protective film.

(A-1) Binder 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 ( Meth)acrylate copolymer (weight average molecular weight: 400,000, glass transition temperature: -1°C)

(A-2) Binder polymer: (meth)acrylate copolymer copolymerized by 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 400,000, glass transfer Temperature: -6℃)

(A-3) Binder polymer: copolymerized by 55 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 20 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate ( Meth)acrylate copolymer (weight average molecular weight: 800,000, glass transition temperature: -28°C)

(B-1) Bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER828, epoxy equivalent is 184g/eq~194g/eq)

(B-2) Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER1055, epoxy equivalent 800g/eq~900g/eq)

(B-3) Dicyclopentadiene epoxy resin (manufactured by DIC, Epiclon HP-7200HH, epoxy equivalent 255g/eq~260g/eq)

(B-4) Cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN-104, epoxy equivalent 220g/eq)

(C) Thermally active latent epoxy resin hardener: dicyandiamine (manufactured by ADEKA, Adeka Hardener EH-3636AS, active hydrogen content is 21g/eq)

(D) Hardening accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., Curezol 2PHZ)

(E-1) Epoxy modified spherical silica filler (manufactured by Admatechs, SC2050MA, average particle size 0.5μm)

(E-2) Vinyl modified spherical silica filler (manufactured by Admatechs, YA050C-MJA, average particle size is 0.05μm)

(E-3) Unshaped silica filler (manufactured by Longsen, SV-10, average particle size 8μm)

(F) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403, methoxy equivalent: 12.7 mmol/g, molecular weight: 236.3)

On a release sheet (made by LINTEC Corporation, SP-PET381031) formed by forming a silicone-based release agent layer on one side of a polyethylene terephthalate (PET) film, use a knife coater to The protective film forming film finally obtained was coated with the aforementioned coating agent for protective film forming film so that the thickness of the protective film forming film became 25 μm, and then dried in an oven at 120° C. for 2 minutes to form a protective film forming film. Then, on the protective film forming film, overlap the peeling surface of the peeling sheet (manufactured by LINTEC Corporation, SP-PET251130) formed by forming a polysiloxane-based release agent layer on one side of the PET film, and stick the two together, and A sheet for forming a protective film was obtained.

[Example 2]

The following coating agent for protective film forming film was prepared by setting the type and blending amount of each component constituting the protective film forming film to the composition shown in Example 2 of Table 1, and the solid content concentration was 50 The protective film formation sheet was produced in the same manner as in Example 1 except for diluting with methyl ethyl ketone as %.

[Comparative Example 1]

The coating agent for the protective film forming film was prepared by setting the types and blending amounts of the components constituting the protective film forming film to the composition shown in the column of Comparative Example 1 in Table 1, and the solid content concentration was 50 The protective film formation sheet was produced in the same manner as in Example 1 except for diluting with methyl ethyl ketone as %.

[Comparative Example 2]

The coating agent for protective film forming film was prepared by setting the type and blending amount of each component constituting the protective film forming film to the composition shown in the column of Comparative Example 2 in Table 1, and the solid content concentration was 50 The protective film formation sheet was produced in the same manner as in Example 1 except for diluting with methyl ethyl ketone as %. In addition, (E-3) Unshaped silica filler (SV-10) was prepared by dispersing in methyl ethyl ketone for 24 hours using a bead mill.

[Test Example 1] <Measurement of Viscoelasticity>

(1) Production of hardened samples

The two release sheets of the protective film forming sheet produced in the examples and comparative examples were peeled off, and the obtained protective film forming film was laminated so that the thickness became 200 μm. The obtained protective film forming layer was heated at 130°C for 2 hours in an oven (under the atmospheric environment) to obtain a protective film with a thickness of 200 μm as a cured product sample.

(2) Measurement of fracture strain and fracture stress at 50℃ after hardening

The obtained cured product sample was cut to prepare a test piece with a width of 5 mm × a length of 20 mm × a thickness of 200 μm. Using a dynamic mechanical analysis device (manufactured by TA Instruments, DMA Q800), a tensile test of the test piece (chuck distance: 5 mm) was performed. After maintaining for 1 minute in an environment with a temperature of 50°C, a tensile test was performed while increasing the load at a constant rate of increase of 1N/min. From the result, the fracture stress and fracture strain are obtained. The results are shown in Table 2.

(3) Measurement of the storage modulus and loss tangent of the cured product sample at 25℃

Cut the hardened sample to prepare a test piece with a width of 4.5 mm × a length of 20 mm × a thickness of 200 μm. Using a dynamic mechanical analysis device (manufactured by TA Instruments, DMA Q800), the storage modulus and loss modulus were measured under the following conditions.

Measurement mode: stretch mode

Measurement start temperature: 0℃

Measurement end temperature: 300°C

Heating rate: 3℃/min

Frequency: 11Hz

Measurement environment: atmosphere

Calculate the loss tangent (tanδ) based on the obtained storage modulus and loss modulus, and find the storage modulus at 25°C and the loss tangent at 25°C. The results are shown in Table 2.

(4) Determination of the peak temperature of the loss tangent of the hardened sample

The loss tangent (tanδ) is calculated from the storage modulus and loss modulus obtained under the above conditions, and the temperature at which this value becomes the maximum is set as the peak temperature of the loss tangent. As a result, it was 52°C in Example 1, 27°C in Example 2, 39°C in Comparative Example 1, and 88°C in Comparative Example 2.

[Test Example 2] <Evaluation of Severability>

On a workpiece composed of a silicon wafer with a thickness of 100μm and an outer diameter of 8 inches, use a sticking device (manufactured by LINTEC, RAD-3600F/12) at 70℃ to stick and cut it into the same shape as the silicon wafer. After the film is formed into a film, it is heated at 130°C for 2 hours in an oven (in an atmospheric environment) to harden, and a wafer with a protective film is produced.

Using an attaching device (manufactured by LINTEC, RAD-2700F/12), a dicing tape for invisible dicing (manufactured by LINTEC, Adwill D-821HS) is attached to the protective film surface of the wafer with the protective film. At this time, the cutting tape is attached to the ring frame.

A laser irradiation device is used to irradiate the laser (wavelength: 1064nm) condensed inside the wafer through the dicing tape and the protective film. At this time, scan and irradiate along the planned cutting line set to form a 5mm x 5mm wafer body.

Then, using an extension device (manufactured by DISCO, DDS2300), the dicing tape attached to the wafer with the protective film was extended at a speed of 100 mm/sec and an extension amount of 10 mm at a temperature of 50°C.

As a result, when the protective film is divided as well as the wafers that are divided at all the planned cutting lines, set the protective film separability to good ("A" in Table 2), and check the divided protective film In the case of wire drawing phenomenon ("B" in Table 2), or in the case where the protective film is not divided ("C" in Table 2), it is judged as defective. The results are shown in Table 2.

[Test Example 3] <Evaluation of Strength of Protective Film>

After evaluating the severability in Test Example 2, using the above-mentioned extension device and using an IR (Infrared) furnace with the heat source set to 550°C, the wafers to be divided and the protective film (ie, a plurality of The laminate of the protective film) and the laminate of the dicing tape (the fourth laminate) are heated for 5 minutes to correct the slack of the dicing tape generated when the dicing tape is stretched. Then, using a die bonder (manufactured by Canon Machinery, Bestem-D02), in a state of 3mm extension, the side of the dicing tape is pressed against the side opposite to the side facing the divided wafer and the protective film Lift the pin, and use the vacuum suction collet to pull up the chip with the protective film that has been ejected, thereby picking up the chip with the protective film.

Observe the picked-up chip with protective film, and judge that the trace of the pin pressed against the protective film is not confirmed as good ("A" in Table 2), and the trace of the pin with no problem will be confirmed The situation is judged as pass ("B" in Table 2), and the situation where traces of sales are confirmed is judged as bad ("C" in Table 2). The results are shown in Table 2. In addition, regarding this evaluation, since the protective film of Comparative Example 2 was not properly divided in Test Example 2, only the protective film provided with Examples 1 and 2 and Comparative Example 1 (the evaluation object is set as part of the cut) The fourth laminate of the film was subjected to this evaluation.

According to Table 2, it can be seen that the protective film forming sheet of the example having a protective film with a breaking strain of 20% or less at 50°C and a breaking stress of 2.0×10 ⁷ Pa or less at 50°C has excellent partitioning properties and the strength of the protective film Also excellent.

[Industrial availability]

The sheet for forming a protective film of the present invention is suitable for use in a case including a step of heating and dividing the protective film, and therefore is extremely useful in industry.

1‧‧‧Protection film forming film

3‧‧‧Sheet for forming protective film

4‧‧‧Support sheet

41‧‧‧Substrate

42‧‧‧Adhesive layer

5‧‧‧Adhesive layer for fixture

6‧‧‧Release sheet

Claims (8)

A sheet for forming a protective film, comprising a first support sheet and a protective film forming film laminated on the first surface side of the first support sheet; the protective film forming film is composed of a curable material; the curable material contains Curable component and binder polymer component; the aforementioned curable component is a thermosetting component, an energy ray curable component, or a mixture of these; the aforementioned thermosetting component is epoxy resin, phenol resin, melamine resin, urea Resins, polyester resins, urethane resins, acrylic resins, polyimide resins, benzoxazine resins, or mixtures thereof; the aforementioned energy-ray curable components are polymers with energy-ray curability, Or at least one component selected from the group consisting of energy-ray curable monomers and oligomers; the aforementioned binder polymer component is acrylic polymer, polyester resin, phenoxy resin, urethane Resin, silicone resin, or rubber-based polymer; when the aforementioned binder polymer component is set to 100 parts by weight, the content of the aforementioned thermosetting component is 50 parts by weight to 1500 parts by weight; and the aforementioned protective film forms a film It has the following characteristics: when the protective film forming film is hardened to become a protective film, the breaking strain of the protective film at 50°C is 20% or less, and the breaking stress at 50°C is 2.0×10 ⁷ Pa or less; the wavelength of the protective film is The transmittance of 1064nm is above 40%. The sheet for forming a protective film according to claim 1, wherein the curable material contains a filler; the filler is silica; the average particle size of the filler is 0.005 μm to 20 μm, and is relatively The total mass of the protective film forming the film, and the content of the aforementioned filler is 5 mass% to 75 mass %. The sheet for forming a protective film according to claim 2, wherein the average particle size of the filler is 0.005 μm to 0.5 μm. A sheet for forming a protective film, comprising a first support sheet and a protective film forming film laminated on the first surface side of the first support sheet; the protective film forming film is composed of a curable material; the curable material contains Curable component, binder polymer component, and filler; the aforementioned curable component is a thermosetting component, an energy-ray curable component, or a mixture of these; the aforementioned thermosetting component is an epoxy resin, a phenol resin, and a melamine resin , Urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, benzoxazine resin, or a mixture of these; the aforementioned energy-ray curable component is a polymer with energy-ray curability Material, or at least one component selected from the group consisting of energy-ray curable monomers and oligomers; the aforementioned binder polymer component is acrylic polymer, polyester resin, phenoxy resin, urethane Ester resin, silicone resin, or rubber-based polymer; when the aforementioned binder polymer component is set to 100 parts by weight, the content of the aforementioned thermosetting component is 50 parts by weight to 1500 parts by weight; the aforementioned filler is two Silicon oxide; the average particle size of the aforementioned filler is 0.005μm to 0.5μm, and the content of the aforementioned filler is 5 mass% to 75% by mass relative to the mass of the entire protective film forming film; and the aforementioned protective film forming film has the following Characteristics: When the protective film forming film is cured into a protective film, the breaking strain at 50°C of the protective film is 20% or less, and the breaking stress at 50°C is 2.0×10 ⁷ Pa or less. The sheet for forming a protective film according to claim 4, wherein the curable material further contains a silane coupling agent; the silane coupling agent does not contain an oligomer type silane coupling agent; when the polymer component of the binder and the curable When the total mass parts of the components is 100 parts by mass, the content of the aforementioned silane coupling agent is 0.1 parts by mass to 5 parts by mass. A sheet for forming a protective film, comprising a first support sheet and a protective film forming film laminated on the first surface side of the first support sheet; the protective film forming film is composed of a curable material; the curable material contains The curable component, the binder polymer component, and the silane coupling agent; the aforementioned curable component is a thermosetting component, an energy-ray curable component, or a mixture of these; the aforementioned thermosetting component is epoxy resin, phenol resin, Melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, polyimide resin, benzoxazine resin, or a mixture of these; the aforementioned energy ray curable component has energy ray curability The polymer or at least one component selected from the group consisting of energy-ray curable monomers and oligomers; the aforementioned binder polymer components are acrylic polymers, polyester resins, phenoxy resins, and amines Carbamate resin, silicone resin, or rubber-based polymer; when the aforementioned binder polymer component is set to 100 parts by weight, the content of the aforementioned thermosetting component is 50 parts by weight to 1500 parts by weight; the aforementioned silane The coupling agent does not contain an oligomer type silane coupling agent; when the total mass parts of the aforementioned binder polymer component and the aforementioned hardening component are set to 100 parts by mass, the content of the aforementioned silane coupling agent is 0.1 to 5 parts by mass Parts; and the protective film forming film has the following characteristics: when the protective film forming film is cured to become a protective film, the breaking strain at 50°C of the protective film is 20% or less, and the breaking stress at 50°C is 2.0×10 ⁷ Pa the following. A method of manufacturing a chip with a protective film, comprising: an attaching step of making the protective film forming film included in the protective film forming sheet described in any one of claims 1 to 6 face the aforementioned The surface of the first support sheet is exposed on the opposite side, and the exposed surface is attached to one surface of the workpiece to obtain a first laminate including the sheet for forming the protective film and the workpiece; the first curing step is performed by The protective film is obtained by curing the protective film forming film in the first laminate; the first dividing step is to maintain the temperature of the protective film provided in the first laminate after the first curing step In a state in the range of 40°C to 70°C, the first support sheet is stretched, and the protective film is divided together with the workpiece to obtain a second laminate. The second laminate system is in the first support sheet A plurality of wafers with a protective film are arranged on one side of the laminated body of the work and the protective film so as to produce a cut surface in the thickness direction; and the first pick-up step is to laminate the second laminate The plurality of protective film-attached wafers included in the body are respectively separated from the first support sheet to obtain the protective film-attached wafer as a processed product; further comprising a modified layer forming step, the modified layer forming step is Before starting the first dividing step, laser light in the infrared region is irradiated to focus on the focal point set inside the workpiece to form a modified layer inside the workpiece. A method for manufacturing a wafer with a protective film, comprising: a layering step of making the protective film forming film included in the protective film forming sheet described in any one of claims 1 to 6 face the aforementioned first 1 The surface of the support sheet is exposed on the opposite side, the exposed surface is attached to one surface of the workpiece, and the first support sheet is peeled from the protective film forming film, thereby obtaining the workpiece and the protective film forming The third layered body of the film; the second curing step is to obtain the protective film by curing the protective film forming film provided in the third layered body; the second attaching step is to include a third substrate and In the processing sheet laminated on the third adhesive layer on the side of the third base material, the layer on the side of the third adhesive layer and the protection in the third layered body after the second curing step The surface of the film side is attached to obtain a fourth laminate including the processing sheet and the third laminate; the second division step is to maintain the temperature of the protective film provided on the fourth laminate at 40 In the state in the range of ℃ to 70℃, the processing sheet included in the fourth laminate is extended, and the protective film is divided together with the workpiece to obtain a fifth laminate. The fifth laminate is A plurality of wafers with a protective film are arranged on one surface of the processing sheet by dividing the laminate of the workpiece and the protective film in a thickness direction to produce a cut surface; and the second pick-up step is to The plurality of protective film-attached wafers included in the fifth layered body are respectively separated from the processing sheet to obtain the protective film-attached wafer as a processed product; further comprising a modified layer forming step, the modified layer The forming step is to irradiate laser light in the infrared region in a manner focused on the focal point set inside the workpiece before starting the second dividing step to form a modified layer inside the workpiece.

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