JPWO2019203021A1 - Work sheet - Google Patents

Abstract

A work processing sheet 1 including at least a base material 2 and an adhesive layer 3 laminated on the first surface side of the base material 2, and has an arithmetic mean roughness on the second surface of the base material 2. (Ra) is 0.01 μm or more and 0.4 μm or less, and the maximum height roughness (Rz) on the second surface of the base material 2 is 0.01 μm or more and 2.5 μm or less, and the base material 2 A work sheet 1 having a light transmittance of 40% or more at a wavelength of 532 nm. The work processing sheet 1 is excellent in laser marking property and has resistance to laser light.

Description

The present invention relates to a work processing sheet, and more particularly to a work processing sheet suitable when the work is laser-marked.

In recent years, semiconductor devices have been manufactured by a mounting method called a face-down method. In this method, when mounting a semiconductor chip having a circuit surface on which electrodes such as bumps are formed, the circuit surface side of the semiconductor chip is joined to a chip mounting portion such as a lead frame. Therefore, the structure is such that the back surface side of the semiconductor chip on which the circuit is not formed is exposed.

Therefore, in order to protect the semiconductor chip, a protective film made of a hard organic material is often formed on the back surface side of the semiconductor chip. Therefore, for example, Patent Document 1 discloses a protective film forming / dicing sheet in which a protective film forming layer capable of forming the above protective film is formed on a dicing sheet. According to this protective film forming / dicing sheet, after forming a protective film on a semiconductor wafer, dicing can be subsequently performed, so that a semiconductor chip with a protective film can be obtained.

The dicing sheet itself includes a base material and an adhesive layer provided on one side thereof. As the pressure-sensitive adhesive of the pressure-sensitive adhesive layer, an ultraviolet-curable pressure-sensitive adhesive whose adhesive strength is reduced by ultraviolet irradiation may be used in order to improve the peelability of the semiconductor chip with a protective film at the time of picking up.

The protective film is usually printed in order to display the product number or the like of the semiconductor chip. As the printing method, a laser marking method of irradiating a protective film with a laser beam is generally used. When laser marking is applied to the protective film, the protective film is irradiated with laser light through the dicing sheet of the protective film forming / dicing sheet.

The protective film is generally made of a black resin composition, and when laser marking is applied to the protective film, the protective film is generally good even if the laser output is relatively weak. Can be printed on.

Japanese Unexamined Patent Publication No. 2006-140348

By the way, in recent years, it has been proposed to apply laser marking to a semiconductor wafer or a glass plate as a work. When laser marking is applied to an inorganic material in this way, printing cannot be performed satisfactorily, the formed printing becomes rough, and there tends to be a problem that the printing accuracy is lowered.

Further, when laser marking is applied to an inorganic material as described above, it is necessary to increase the laser output relatively, which makes it easy for the base material of the dicing sheet to burn. In that case, the light transmittance of the burnt portion decreases, and the print formed on the work cannot be visually recognized well. Further, when the pressure-sensitive adhesive layer of the dicing sheet is UV-curable, when the pressure-sensitive adhesive layer is UV-cured, the transparency of ultraviolet rays in the burnt portion of the base material is deteriorated, and as a result, the pressure-sensitive adhesive layer of the portion is deteriorated. However, the adhesive cannot be sufficiently cured, and the adhesive remains on the picked-up chip, which causes a problem of adhesive residue.

The present invention has been made in view of the above-mentioned actual conditions, and an object of the present invention is to provide a work processing sheet having excellent laser marking properties and resistance to laser light.

In order to achieve the above object, firstly, the present invention is a work processing sheet including at least a base material and an adhesive layer laminated on the first surface side of the base material. The arithmetic mean roughness (Ra) on the second surface of the base material is 0.01 μm or more and 0.4 μm or less, and the maximum height roughness (Rz) on the second surface of the base material is 0. Provided is a work processing sheet characterized by having a light transmittance of 01 μm or more and 2.5 μm or less and having a wavelength of 532 nm of the base material of 40% or more (Invention 1).

In the above invention (Invention 1), since the physical properties of the base material are as described above, the laser light used for laser marking, particularly the laser light having a wavelength of 532 nm, easily passes through the base material and the work processing sheet. It becomes a thing. As a result, printing by laser marking can be performed satisfactorily on the work, and printing with high accuracy can be formed. In addition, it is difficult for the base material to absorb the energy of the laser light, and it is possible to prevent the base material from being burnt and printed. Therefore, there is no decrease in light transmittance due to burning of the base material, and the print formed on the work can be satisfactorily visually recognized through the work processing sheet.

In the above invention (Invention 1), the light transmittance of the base material at a wavelength of 400 nm is preferably 40% or more (Invention 2).

In the above inventions (Inventions 1 and 2), the light transmittance of the base material at a wavelength of 800 nm is preferably 45% or more (Invention 3).

The work processing sheet according to the above inventions (Inventions 1 to 3) is preferably used for applications including a step of laser marking the work through the work processing sheet (Invention 4).

The work processing sheet according to the above inventions (Inventions 1 to 4) is preferably used for dicing (Invention 5).

The work processing sheet according to the above invention (Invention 5) is preferably used for stealth dicing (Invention 6).

The work processing sheet according to the present invention has excellent laser marking properties and is resistant to laser light.

It is sectional drawing of the work processing sheet which concerns on one Embodiment of this invention. It is sectional drawing which shows the use example of the work processing sheet which concerns on one Embodiment of this invention, specifically, a laminated structure.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a cross-sectional view of a work processing sheet according to an embodiment of the present invention. As shown in FIG. 1, the work processing sheet 1 according to the present embodiment includes a base material 2, an adhesive layer 3 laminated on the first surface side (upper side in FIG. 1) of the base material 2. It is configured to include a release sheet 6 laminated on the pressure-sensitive adhesive layer 3. The release sheet 6 is peeled off and removed when the work processing sheet 1 is used to protect the pressure-sensitive adhesive layer 3 until then, and may be omitted from the work processing sheet 1 according to the present embodiment. Here, the surface of the base material 2 on the adhesive layer 3 side is referred to as a "first surface", and the surface on the opposite side (lower surface in FIG. 1) is referred to as a "second surface".

The work processing sheet 1 according to the present embodiment is used, for example, for holding a work in a laser marking step and a dicing step on a semiconductor wafer or a glass plate as a work, but is not limited thereto. ..

Further, the laser marking in the present embodiment is intended not only for members made of inorganic materials such as semiconductor wafers and glass plates, but also for members made of organic materials such as protective films and adhesive layers laminated on them, or the surface layer of packages. It becomes.

The work processing sheet 1 according to the present embodiment is usually formed into a long length, wound into a roll shape, and used in a roll-to-roll manner.

1. 1. Components of Work Sheet (1) Base Material (1-1) Physical Properties The arithmetic mean roughness (Ra) on the second surface of the base material 2 (hereinafter sometimes referred to as the "back surface of the base material 2") is , 0.01 μm or more and 0.4 μm or less, and the maximum height roughness (Rz) is 0.01 μm or more and 2.5 μm or less. Further, the light transmittance of the base material 2 at a wavelength of 532 nm is 40% or more. The arithmetic mean roughness (Ra) and maximum height roughness (Rz) in the present specification are measured based on JIS B0601: 1999. Further, the light transmittance in the present specification is measured by a direct light receiving method using a spectrophotometer as a measuring instrument. In each case, the details of the measurement method are as shown in the test examples described later.

The arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the second surface of the base material 2 are in the above ranges, and the light transmittance of the base material 2 at a wavelength of 532 nm is as described above. The laser light used for laser marking, particularly the laser light having a wavelength of 532 nm, easily passes through the base material 2 and thus the work processing sheet 1. As a result, printing by laser marking can be performed satisfactorily on the work, and printing with high accuracy can be formed. Further, it is difficult for the base material 2 to absorb the energy of the laser light, and it is possible to prevent the base material 2 from being burnt and printed. Therefore, there is no decrease in light transmittance due to the burning of the base material 2, and the print formed on the work can be satisfactorily visually recognized through the work processing sheet 1. Further, when the pressure-sensitive adhesive layer 3 is composed of an ultraviolet curable pressure-sensitive adhesive, when the pressure-sensitive adhesive layer 3 is irradiated with ultraviolet rays via the base material 2, the ultraviolet rays reach the pressure-sensitive adhesive layer 3 without any problem. However, the pressure-sensitive adhesive layer 3 cures well. Therefore, the problem of adhesive residue that the adhesive adheres to the picked-up chip is unlikely to occur. That is, the work processing sheet 1 according to the present embodiment is excellent in laser marking property and has resistance to laser light.

Further, when the base material 2 satisfies the above physical properties, the transparency of the laser light used in the stealth dicing becomes good, and the processability of the stealth dicing becomes excellent.

Further, when the arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the second surface of the base material 2 are within the above ranges, blocking of the work processing sheet 1 can also be suppressed. That is, the work processing sheet 1 can be satisfactorily unwound from the wound body, and unintended peeling at the interface is unlikely to occur at the time of unwinding.

The upper limit of the arithmetic mean roughness (Ra) on the back surface of the base material 2 is 0.4 μm or less, preferably 0.2 μm or less, and particularly preferably less than 0.1 μm as described above. When the arithmetic mean roughness (Ra) exceeds 0.4 μm, the unevenness on the back surface of the base material 2 hinders the transmission of laser light. On the other hand, the lower limit of the arithmetic mean roughness (Ra) is 0.01 μm or more, preferably 0.015 μm or more, from the viewpoint of preventing blocking.

The maximum height roughness (Rz) on the back surface of the base material 2 is 2.5 μm or less, preferably 1.5 μm or less, and particularly preferably 0.5 μm or less as described above. When the maximum height roughness (Rz) exceeds 2.5 μm, the unevenness on the back surface of the base material 2 hinders the transmission of laser light. On the other hand, the lower limit of the maximum height roughness (Rz) is 0.01 μm or more, preferably 0.013 μm or more, and particularly preferably 0.1 μm or more, from the viewpoint of preventing blocking.

The pressure-sensitive adhesive layer 3 is laminated on the first surface of the base material 2 (hereinafter, may be referred to as "the front surface of the base material 2"), and the unevenness of the front surface of the base material 2 is filled with the pressure-sensitive adhesive layer 3. The arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the front surface of the base material 2 are not particularly limited. However, if these values are too large, the unevenness on the front surface of the base material 2 may not be filled by the pressure-sensitive adhesive layer 3, so the arithmetic mean roughness (Ra) on the front surface of the base material 2 is set as an upper limit value. , 2.5 μm or less is preferable. The lower limit of the arithmetic mean roughness (Ra) on the front surface of the base material 2 is not particularly limited, but is usually 0.01 μm or more due to the film forming method. Further, for the above reason, the maximum height roughness (Rz) of the front surface of the base material 2 is preferably 2.5 μm or less as an upper limit value. The lower limit of the maximum height roughness (Rz) of the front surface of the base material 2 is not particularly limited, but is usually 0.01 μm or more due to the film forming method of the film.

As described above, the light transmittance of the base material 2 at a wavelength of 532 nm is 40% or more, preferably 50% or more, particularly preferably 60% or more, and further preferably 75% or more. When the light transmittance at a wavelength of 532 nm is less than 40%, the energy of the laser light (particularly the laser light having a wavelength of 532 nm) mainly used for laser marking is absorbed by the base material 2, and the base material 2 is likely to be burnt. Become. The upper limit of the light transmittance at a wavelength of 532 nm is not particularly limited and may be 100%.

The light transmittance of the base material 2 at a wavelength of 400 nm is preferably 40% or more, more preferably 45% or more, particularly preferably 50% or more, and further preferably 75% or more. Is preferable. When the light transmittance at a wavelength of 400 nm is 40% or more, visible light is easily transmitted, and therefore, the printing formed on the work through the base material 2 and the work processing sheet 1 is better. It can be visually recognized.

Further, the light transmittance of the base material 2 at a wavelength of 800 nm is preferably 45% or more, more preferably 55% or more, particularly preferably 65% or more, and further preferably 75% or more. Is preferable. When the light transmittance at a wavelength of 800 nm is 45% or more, visible light is easily transmitted, and therefore, the printing formed on the work through the base material 2 and the work processing sheet 1 is better. It can be visually recognized.

(1-2) Thickness The thickness of the base material 2 is not particularly limited as long as it can function appropriately in each process in which the work processing sheet 1 is used. Specifically, the thickness of the base material 2 is preferably 20 μm or more, particularly preferably 25 μm or more, and further preferably 50 μm or more. The thickness of the base material 2 is preferably 450 μm or less, particularly preferably 400 μm or less, and further preferably 350 μm or less. When the thickness of the base material 2 is within the above range, the workability of the work and the transparency of the laser beam can be well maintained.

(1-3) Material The base material 2 is preferably composed of a resin film. Specific examples of the resin film constituting the base material 2 include polyethylene films such as low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, and high-density polyethylene (HDPE) film, polypropylene film, and ethylene-propylene. Polyethylene-based films such as copolymer films, polybutene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, norbornene resin films; ethylene-vinyl acetate copolymer films, ethylene- (meth) acrylic acid Ethylene-based copolymer films such as polymer films and ethylene- (meth) acrylic acid ester copolymer films; polyvinyl chloride-based films such as polyvinyl chloride films and vinyl chloride copolymer films; polyethylene terephthalate films and polybutylene terephthalates. Polyester-based films such as films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; fluororesin films and the like can be mentioned. Further, modified films such as these crosslinked films and ionomer films are also used. Further, it may be a laminated film in which a plurality of the same type or different types of the above films are laminated. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

Among the above, polyolefin-based films, polyvinyl chloride-based films, and ethylene-based copolymer films are preferable. Among the polyolefin-based films, polyethylene films are preferable, and low-density polyethylene (LDPE) films are particularly preferable. Further, among the polyvinyl chloride-based films, the polyvinyl chloride-based film is particularly preferable, and among the ethylene-based copolymer films, the ethylene- (meth) acrylic acid copolymer film is particularly preferable. According to these resin films, it is easy to satisfy the above-mentioned physical properties. Further, these resin films are also preferable from the viewpoints of expandability, work stickability, chip peeling property and the like.

For the purpose of improving the adhesion to the pressure-sensitive adhesive layer 3 laminated on the surface of the resin film, one or both sides thereof may be subjected to surface treatment or primer treatment by an oxidation method, an unevenness method or the like, if desired. it can. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment, and examples of the unevenness method include sandblasting and sandblasting. Examples include a thermal spraying method.

The base material 2 may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler in the resin film.

(1-4) Manufacturing Method The resin film constituting the base material 2 can be manufactured by a manufacturing method according to the type of the resin film, but is mainly manufactured by the extrusion molding T-die method. In order to produce a resin film having the above-mentioned arithmetic mean roughness (Ra), maximum height roughness (Rz) and light transmittance, it is necessary to prevent air (air bubbles) from being entrained during the formation of the resin film. There is. For example, by extrusion molding under reduced pressure, vacuum, or the like, it is possible to suppress the entrainment of such air and produce a resin film having no bubble traces. Further, by adjusting the surface roughness of each process roll such as a cooling roll at the time of film formation, a resin film having no bubble marks can be produced. However, the method for producing a resin film having the above-mentioned arithmetic mean roughness (Ra), maximum height roughness (Rz) and light transmittance is not limited to this.

(2) Adhesive Layer The pressure-sensitive adhesive layer 3 included in the work processing sheet 1 according to the present embodiment may be composed of an active energy ray non-curable pressure-sensitive adhesive or an active energy ray-curable pressure-sensitive adhesive. You may. The active energy ray non-curable pressure-sensitive adhesive preferably has desired adhesive strength and removability, and is, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, or a polyester-based pressure-sensitive adhesive. Agents, polyvinyl ether adhesives and the like can be used. Among these, an acrylic pressure-sensitive adhesive that can effectively suppress the dropping of the work or the work piece in the dicing step or the like is preferable.

On the other hand, since the adhesive strength of the active energy ray-curable pressure-sensitive adhesive is lowered by irradiation with active energy rays, it is easy to separate the work or work piece from the work sheet 1 by irradiating with active energy rays. Can be separated into. In the present embodiment, the active energy ray-curable pressure-sensitive adhesive is preferably an ultraviolet-curable pressure-sensitive adhesive. As a result, the above-mentioned effect of suppressing adhesive residue becomes apparent and is exhibited.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3 may be mainly composed of a polymer having active energy ray-curable property, or a polymer having no active energy ray-curable property and an active energy ray. It may be mainly composed of a mixture with a curable polyfunctional monomer and / or an oligomer.

The case where the active energy ray-curable pressure-sensitive adhesive contains a polymer having active energy ray-curability as a main component will be described below.

The polymer having active energy ray curability is a (meth) acrylic acid ester (co) polymer (A) in which a functional group having active energy ray curability (active energy ray curable group) is introduced into the side chain (hereinafter referred to as “A)”. It may be referred to as "active energy ray-curable polymer (A)"). This active energy ray-curable polymer (A) is a (meth) acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a substituent bonded to the functional group. ), It is preferable that it is obtained by reacting with.

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

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

More specific examples of the functional group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like. These are used alone or in combination of two or more.

The (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1) includes alkyl (meth) acrylate, cycloalkyl (meth) acrylate, and benzyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms. Is used. Among these, alkyl (meth) acrylates in which the alkyl group has 1 to 18 carbon atoms are particularly preferably methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate. , 2-Ethylhexyl (meth) acrylate and the like are used.

The acrylic copolymer (a1) contains a structural unit derived from the functional group-containing monomer in a proportion of usually 3 to 100% by mass, preferably 5 to 40% by mass, and is a (meth) acrylic acid ester monomer or a component thereof. The structural unit derived from the derivative is usually contained in an amount of 0 to 97% by mass, preferably 60 to 95% by mass.

The acrylic copolymer (a1) can be obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof by a conventional method, but in addition to these monomers, Dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like may be copolymerized.

By reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a substituent bonded to the functional group, an active energy ray-curable polymer (a2). A) is obtained.

The substituent contained in the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of functional group of the functional group-containing monomer unit contained in 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 an amino group, a carboxyl group or an aziridinyl group. preferable.

The unsaturated group-containing compound (a2) contains 1 to 5 active energy ray-polymerizable carbon-carbon double bonds, preferably 1 to 2 per molecule. Specific examples of such an unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(. Bisacryloyloxymethyl) ethyl isocyanate; Acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, polyol compound, hydroxyethyl (meth) Acryloyl monoisocyanate compound obtained by reaction with acrylate; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl- 2-Oxazoline and the like can be mentioned.

The unsaturated group-containing compound (a2) is usually used in a proportion of 10 to 100 mol%, preferably 20 to 95 mol%, based on the functional group-containing monomer of the acrylic copolymer (a1).

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the temperature, pressure, solvent, time, presence / absence of catalyst, and catalyst of the reaction depend on the combination of the functional group and the substituent. The type of can be appropriately selected. As a result, the functional group present in the acrylic copolymer (a1) reacts with the substituent in the unsaturated group-containing compound (a2), and the unsaturated group is contained in the acrylic copolymer (a1). It is introduced into the side chain to obtain an active energy ray-curable polymer (A).

The weight average molecular weight of the active energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 to 1.5 million, and further 200,000 to 1,000,000. It is preferable to have it. The weight average molecular weight (Mw) in the present specification is a polystyrene-equivalent value measured by a gel permeation chromatography method (GPC method).

Even when the active energy ray-curable pressure-sensitive adhesive contains a polymer having active energy ray-curable as a main component, the active energy ray-curable pressure-sensitive adhesive is an active energy ray-curable monomer and / or an oligomer (B). ) May be further contained.

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

Examples of the active energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic acid esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethyl propantri (meth) acrylate, and the like. Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene Examples thereof include polyfunctional acrylic acid esters such as glycol di (meth) acrylate and dimethylol tricyclodecandi (meth) acrylate, polyester oligo (meth) acrylate, and polyurethane oligo (meth) acrylate.

When the active energy ray-curable monomer and / or oligomer (B) is blended, the content of the active energy ray-curable monomer and / or oligomer (B) in the active energy ray-curable pressure-sensitive adhesive is 5 to 80. It is preferably mass%, and particularly preferably 20 to 60 mass%.

Here, when ultraviolet rays are used as the active energy rays for curing the active energy ray-curable resin composition, it is preferable to add a photopolymerization initiator (C), and the photopolymerization initiator (C) By using it, the polymerization curing time and the amount of light irradiation can be reduced.

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, methyl benzoin benzoate, and benzoin dimethyl ketal. 2,4-Diethylthioxanthone, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4) 6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1- [4- (1-propenyl) phenyl] propanone}, 2, Examples thereof include 2-dimethoxy-1,2-diphenylethane-1-one. These may be used alone or in combination of two or more.

When the photopolymerization initiator (C) contains the active energy ray-curable polymer (A) (active energy ray-curable monomer and / or oligomer (B), the active energy ray-curable polymer (A) ) And 100 parts by mass of the total amount of the active energy ray-curable monomer and / or oligomer (B)) 0.1 to 10 parts by mass, particularly in the range of 0.5 to 6 parts by mass. It is preferable to be used in.

In the active energy ray-curable pressure-sensitive adhesive, other components may be appropriately added in addition to the above components. Examples of other components include a polymer component or an oligomer component (D) having no active energy ray curability, a cross-linking agent (E), and the like.

Examples of the polymer component or oligomer component (D) having no active energy ray curability include polyacrylic acid ester, polyester, polyurethane, polycarbonate, and polyolefin, and the weight average molecular weight (Mw) is 3000 to 2.5 million. Polymers or oligomers are preferred.

As the cross-linking agent (E), a polyfunctional compound having reactivity with a functional group of the active energy ray-curable polymer (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 alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, etc. Reactive phenolic resins and the like can be mentioned.

By blending these other components (D) and (E) with the active energy ray-curable pressure-sensitive adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesiveness with other layers, and the storage stability. Etc. can be improved. The blending amount of these other components is not particularly limited, and is appropriately determined in the range of 0 to 40 parts by mass with respect to 100 parts by mass of the active energy ray-curable polymer (A).

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

As the polymer component having no active energy ray curability, for example, the same component as the acrylic copolymer (a1) described above can be used. The content of the polymer component having no active energy ray curability in the active energy ray-curable resin composition is preferably 20 to 99.9% by mass, and particularly preferably 30 to 80% by mass.

As the active energy ray-curable polyfunctional monomer and / or oligomer, the same component (B) as described above is selected. The blending ratio of the polymer component having no active energy ray curability and the polyfunctional monomer and / or oligomer having active energy ray curability is 10 to 150 mass by mass of the polyfunctional monomer and / or oligomer with respect to 100 parts by mass of the polymer component. It is preferably parts, and particularly preferably 25 to 100 parts by mass.

In this case as well, the photopolymerization initiator (C) and the cross-linking agent (E) can be appropriately blended in the same manner as described above.

The thickness of the pressure-sensitive adhesive layer 3 is not particularly limited as long as it can function appropriately in each step in which the work processing sheet 1 is used. Specifically, it is preferably 1 to 50 μm, particularly preferably 2 to 30 μm, and further preferably 3 to 20 μm.

(3) Release sheet The release sheet 6 in the present embodiment protects the pressure-sensitive adhesive layer 3 until the work processing sheet 1 is used. The release sheet 6 in the present embodiment is directly laminated on the pressure-sensitive adhesive layer 3, but is not limited to this, and another layer (die bonding film or the like) is laminated on the pressure-sensitive adhesive layer 3. The release sheet 6 may be laminated on the other layer.

The structure of the release sheet 6 is arbitrary, and examples thereof include a plastic film peeled with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, a silicone type, a fluorine type, a long chain alkyl type or the like can be used, but among these, a silicone type that can obtain stable performance at low cost is preferable. The thickness of the release sheet is not particularly limited, but is usually about 20 to 250 μm.

(4) Other Members In the work processing sheet 1 according to the present embodiment, the adhesive layer is laminated on the surface of the adhesive layer 3 opposite to the base material 2 (hereinafter, may be referred to as “adhesive surface”). It may have been done. In this case, the work processing sheet 1 according to the present embodiment can be used as a dicing / die bonding sheet by providing the adhesive layer. In such a dicing / die bonding sheet, a work is attached to the surface of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the work to obtain an individualized adhesive layer. Stacked chips can be obtained. The individualized adhesive layer allows the chip to be easily fixed to the object on which the chip is mounted. As the material constituting the adhesive layer, a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, a material containing a B stage (semi-curable) thermosetting adhesive component, or the like is used. Is preferable.

Further, in the work processing sheet 1 according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer 3. In this case, the work processing sheet 1 according to the present embodiment can be used as a protective film forming and dicing sheet. In such a protective film forming and dicing sheet, a work is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the protective film forming layer is diced together with the work to be individualized. A chip in which a protective film forming layer is laminated can be obtained. As the object to be cut, it is preferable to use one having a circuit formed on one side, and in this case, a protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. .. The individualized protective film forming layer is cured at a predetermined timing (preferably before the dicing step), so that a protective film having sufficient durability can be formed on the work or the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

In the above case, the target of laser marking is not the work itself but the adhesive layer or the protective film. However, even in these cases, the above-mentioned excellent laser marking property and laser light resistance effect can be obtained as well.

2. Method for Manufacturing Work Processing Sheet In order to produce the work processing sheet 1, as an example, an adhesive containing an adhesive constituting the pressure-sensitive adhesive layer 3 and, if desired, a solvent on the release surface of the release sheet 6. The coating agent for the layer is applied and dried to form the pressure-sensitive adhesive layer 3. After that, the base material 2 is pressure-bonded to the exposed surface of the pressure-sensitive adhesive layer 3 to obtain a work processing sheet 1 composed of the base material 2, the pressure-sensitive adhesive layer 3, and the release sheet 6.

It is preferable that the pressure-sensitive adhesive layer 3 in the present embodiment can be attached to a jig such as a ring frame. In this case, when the pressure-sensitive adhesive layer 3 is made of an active energy ray-curable pressure-sensitive adhesive, it is preferable not to cure the active energy ray-curable pressure-sensitive adhesive. As a result, the adhesive force to the jig such as the ring frame can be maintained high.

The laminate of the base material 2 and the pressure-sensitive adhesive layer 3 may be half-cut if desired, and may have a desired shape, for example, a circular shape corresponding to a work (semiconductor wafer). In this case, the excess portion generated by the half cut may be appropriately removed.

3. 3. How to use the work processing sheet The work processing sheet 1 according to the present embodiment is preferably used for dicing. Examples of the type of dicing include blade dicing, stealth dicing, plasma dicing, laser dicing, water dicing and the like, and among them, blade dicing and stealth dicing are preferable. Examples of the work include, but are not limited to, semiconductor wafers made of inorganic materials, glass plates, and various other packages.

A method of manufacturing a chip by blade dicing or stealth dicing from a semiconductor wafer as a work as an example using the work processing sheet 1 according to the present embodiment will be described below.

First, the rolled roll-shaped workpiece processing sheet 1 is unwound while peeling off the release sheet 6, and as shown in FIG. 2, the semiconductor wafer 7 and the ring frame are formed on the adhesive layer 3 of the workpiece processing sheet 1. 8 is pasted. As a result, a laminated structure having a structure in which the semiconductor wafer 7 and the ring frame 8 are laminated on the surface of the work processing sheet 1 on the adhesive layer 3 side (hereinafter, may be referred to as “laminated structure L”) is obtained. ..

Next, the laminated structure L is subjected to a laser marking step. Specifically, a laser irradiation device for laser marking is used to irradiate the semiconductor wafer 7 with laser light through the work processing sheet 1 to print the semiconductor wafer 7 as desired. As the laser light, a laser light having a wavelength of 532 nm is mainly used.

In the work processing sheet 1 according to the present embodiment, since the physical properties of the base material 2 are set as described above, laser light is easily transmitted, and therefore, printing by laser marking on the work is satisfactorily performed. This can be done, and highly accurate printing can be formed. Further, since it is difficult for the base material 2 to absorb the energy of the laser light, it is possible to prevent the base material 2 from being burnt. Therefore, there is no decrease in light transmittance due to the burning of the base material 2, and the print formed on the work can be satisfactorily visually recognized through the work processing sheet 1.

Next, the laminated structure L is subjected to a dicing step. In the case of blade dicing, a chip is obtained by cutting and dividing the semiconductor wafer 7 using a dicing blade. After that, by carrying out an expanding step of extending the work processing sheet 1, the interval between the chips is widened so that the work sheet 1 can be easily picked up in the next pick-up step.

On the other hand, in the case of stealth dicing, the semiconductor wafer 7 is irradiated with laser light through the workpiece processing sheet 1 by using a laser irradiation device for division processing (laser dicing), and the inside of the semiconductor wafer 7 is radiated. A modified layer is formed in. Since the physical properties of the base material 2 are set as described above, the transmission of laser light by the laser dicer is also excellent. After that, a force (tensile force in the main surface inward direction) is applied to the semiconductor wafer 7 by carrying out an expanding step of extending the work processing sheet 1. As a result, the semiconductor wafer 7 to be attached to the work processing sheet 1 is divided to obtain chips.

Next, the insert is picked up from the work processing sheet 1 using the pickup device. Here, when the pressure-sensitive adhesive layer 3 of the work processing sheet 1 is made of an active energy ray-curable pressure-sensitive adhesive, the active energy rays are directed to the pressure-sensitive adhesive layer 3 via the base material 2 before the pickup. It is preferable to irradiate. As a result, the adhesive strength of the pressure-sensitive adhesive layer 3 can be reduced, and the chips can be easily picked up. As the active energy ray, ultraviolet rays, electron beams and the like are usually used, and ultraviolet rays that are easy to handle are particularly preferable.

Irradiation of the ultraviolet rays, a high-pressure mercury lamp, Fusion lamps, can be performed by a xenon lamp, LED, etc., the dose of ultraviolet ray is illuminance 50 mW / cm ² or more, and preferably 1000 mW / cm ² or less. Quantity of ultraviolet light is preferably at 50 mJ / cm ² or more, particularly preferably at 80 mJ / cm ² or more, and further preferably not 100 mJ / cm ² or more. The amount of ultraviolet light is ^{preferably 2000 mJ / cm 2} or less, particularly preferably 1000 mJ / cm ² or less, and further preferably 500 mJ / cm ² or less.

As described above, since the burning of the base material 2 due to the laser marking is suppressed, the pressure-sensitive adhesive layer 3 is good even if the pressure-sensitive adhesive layer 3 is irradiated with ultraviolet rays through the base material 2 as described above. Hardens. Therefore, the problem of adhesive residue that the adhesive adheres to the picked-up chip is unlikely to occur.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer may be provided between the base material 2 and the pressure-sensitive adhesive layer 3 on the work processing sheet 1, or on the surface of the base material 2 opposite to the pressure-sensitive adhesive layer 3.

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

[Example 1]
(1) Preparation of base material A base made of a resin film having a thickness of 80 μm by extruding a low-density polyethylene resin composition with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “Laboplast Mill”). The material was prepared. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

(2) Preparation of Coating Agent for Adhesive Layer A methacryloyloxyethyl isocyanate (MOI) is added to a copolymer obtained by copolymerizing 72 parts by mass of butyl acrylate and 28 parts by mass of 2-hydroxyethyl acrylate (HEA). , 80 mol% of the copolymer was reacted with HEA to obtain an active energy ray-curable acrylic polymer (weight average molecular weight 500,000) having an active energy ray-polymerizable group in the side chain.

3.0 parts by mass of photopolymerization initiator (manufactured by BASF, product name "Irgacure 184") and isocyanate compound with respect to 100 parts by mass (solid content concentration; the same applies hereinafter) of the above active energy ray-curable acrylic polymer. (Manufactured by Toso Co., Ltd., product name "Coronate L") 1.0 part by mass was blended and diluted with a solvent to obtain a coating agent for a pressure-sensitive adhesive layer.

(3) Manufacture of Work Sheet A release sheet (manufactured by Lintec Corporation, product name "SP-PET381031") in which a silicone-based release agent layer is formed on one side of a 38 μm-thick polyethylene terephthalate film is prepared. The above-mentioned coating agent for an adhesive layer was applied on the peeling surface of the release sheet with a knife coater and dried to form an adhesive layer having a thickness of 10 μm. The front surface of the base material produced above was overlapped on the pressure-sensitive adhesive layer, and both were bonded to each other to obtain a laminate composed of a base material (80 μm) / a pressure-sensitive adhesive layer (10 μm) / a release sheet.

The laminate obtained above was half-cut from the substrate side so as to cut the laminate of the substrate and the pressure-sensitive adhesive layer to form a circular workpiece processing sheet having a diameter of 370 mm.

[Example 2]
The polyvinyl chloride resin composition was extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill") to prepare a base material made of a resin film having a thickness of 80 μm. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

A work processing sheet was produced in the same manner as in Example 1 except that the above base material was used.

[Example 3]
A base consisting of a resin film having a thickness of 80 μm, which is formed by extruding a resin composition of an ethylene- (meth) acrylic acid copolymer with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “Laboplast Mill”). The material was prepared. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

A work processing sheet was produced in the same manner as in Example 1 except that the above base material was used.

[Comparative Example 1]
A base consisting of a resin film having a thickness of 80 μm, which is formed by extruding a resin composition of an ethylene- (meth) acrylic acid copolymer with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “Laboplast Mill”). The material was prepared. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

A work processing sheet was produced in the same manner as in Example 1 except that the above base material was used.

[Comparative Example 2]
The polyethylene resin composition was extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill") to prepare a base material made of a resin film having a thickness of 110 μm. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

A work processing sheet was produced in the same manner as in Example 1 except that the above base material was used.

[Comparative Example 3]
The resin composition of low-density polyethylene was extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill") to prepare a base material made of a resin film having a thickness of 80 μm. The surface roughness (arithmetic mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method described later and was as shown in Table 1.

A work processing sheet was produced in the same manner as in Example 1 except that the above base material was used.

[Test Example 1] <Measurement of surface roughness of base material>
The arithmetic average roughness (Ra; unit μm) and maximum height roughness (Rz; unit μm) of the back surface of the base material prepared in Examples and Comparative Examples are measured by a contact type surface roughness meter (manufactured by Mitutoyo Co., Ltd., product name). Using "SV3000S4"), the measurement was performed in accordance with JIS B0601: 1999 under the following measurement conditions. The results are shown in Table 1.
[Measurement condition]
Evaluation length: 10 mm
Reference length: 2.5 mm
Scanning speed: 1.0 mm / sec
Cut-off value: 0.25 mm

[Test Example 2] <Measurement of light transmittance>
For the base materials produced in Examples and Comparative Examples, the light transmittance was measured by the direct light receiving method using an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, product name "UV-3600"), and the wavelength was measured. Light transmittances (%) of 400 nm, 532 nm and 800 nm were extracted. The results are shown in Table 1.

[Test Example 3] <Evaluation of laser marking property>
Using a tape mounter device (manufactured by Lintec Corporation, product name "RAD-2700F / 12"), the release sheet was peeled off from the workpiece processing sheets of Examples and Comparative Examples, and the exposed adhesive layer was polished to # 2000. It was attached to the polished surface of a silicon wafer (diameter: 12 inches, thickness: 350 μm). At the same time, the exposed adhesive layer was attached to the ring frame.

Using a laser marker (manufactured by EO TECHNICS, product name "CSM300M"), a silicon wafer is irradiated with a laser beam having a wavelength of 532 nm through a work processing sheet, and the silicon wafer is printed by laser marking (character size: 0). .2 mm × 0.3 mm, character spacing: 0.3 mm, number of characters: 20 characters).

After that, the work processing sheet was peeled off from the silicon wafer, and the printing formed on the silicon wafer was confirmed using a digital microscope (manufactured by KEYENCE, product name "Digital Microscope VHX-1000", magnification: 100 times). .. As a result, the print was not rough and was formed with high accuracy ◎, the print was slightly rough, but the print was formed with a certain degree of accuracy 〇, the print was rough and accurate. Those with a low value were evaluated as x. The results are shown in Table 1.

[Test Example 4] <Evaluation of laser light resistance>
In the same manner as in Test Example 3, the silicon wafer was irradiated with laser light having a wavelength of 532 nm through the work processing sheet, and printing was performed on the silicon wafer. Then, the work processing sheet was peeled off from the silicon wafer, and it was visually confirmed whether or not the base material of the work processing sheet was burnt (printed) by laser light. As a result, those having no burning (printing) on the base material were evaluated as ◯, and those having burning (printing) on the base material were evaluated as x. The results are shown in Table 1.

As can be seen from Table 1, the workpiece processing sheet obtained in the examples was excellent in laser marking property and resistant to laser light.

The work processing sheet according to the present invention is suitably used for applications including a step of laser marking a work such as a semiconductor wafer or a glass plate through the work processing sheet.

1 ... Work sheet 2 ... Base material 3 ... Adhesive layer 6 ... Release sheet 7 ... Semiconductor wafer 8 ... Ring frame

Claims (6)

A work processing sheet including at least a base material and an adhesive layer laminated on the first surface side of the base material.
The arithmetic mean roughness (Ra) on the second surface of the base material is 0.01 μm or more and 0.4 μm or less.
The maximum height roughness (Rz) on the second surface of the base material is 0.01 μm or more and 2.5 μm or less.
A work processing sheet characterized in that the light transmittance of the base material at a wavelength of 532 nm is 40% or more. The work processing sheet according to claim 1, wherein the light transmittance of the base material at a wavelength of 400 nm is 40% or more. The work processing sheet according to claim 1 or 2, wherein the light transmittance of the base material at a wavelength of 800 nm is 45% or more. The work processing sheet according to any one of claims 1 to 3, wherein the work is used for an application including a step of performing laser marking on the work through the work processing sheet. The work processing sheet according to any one of claims 1 to 4, wherein the work sheet is used for dicing. The work processing sheet according to claim 5, which is used for stealth dicing.

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