WO2019203021A1

WO2019203021A1 - Workpiece processing sheet

Info

Publication number: WO2019203021A1
Application number: PCT/JP2019/015091
Authority: WO
Inventors: 由希森田; 茂之山下
Original assignee: リンテック株式会社
Priority date: 2018-04-18
Filing date: 2019-04-05
Publication date: 2019-10-24
Also published as: JP7325403B2; TW202004876A; TWI797309B; KR20200144090A; JPWO2019203021A1; CN111989764A

Abstract

A workpiece processing sheet 1 provided with at least a base material 2 and an adhesive agent layer 3 stacked on a first surface side of the base material 2, wherein: the base material 2 on a second surface thereof has an arithmetic-mean coarseness (Ra) of not less than 0.01 μm and not more than 0.4 μm; the base material 2 has on the second surface thereof a maximum height coarseness (Rz) of not less than 0.01 μm and not more than 2.5 μm; and the base material 2 has a light transmittance of not less than 40% with respect to wavelength of 532 nm. The workpiece processing sheet 1 has excellent laser marking property and resistance to laser light.

Description

Work sheet

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

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

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

In addition, said dicing sheet itself is equipped with the base material and the adhesive layer provided in the single side | surface. As the pressure-sensitive adhesive for 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 at the time of picking up the semiconductor chip with a protective film.

The above protective film is usually printed in order to display the product number of the semiconductor chip. As the printing method, a laser marking method in which a protective film is irradiated with laser light has become common. When laser marking is performed on the protective film, the protective film is irradiated with laser light through the dicing sheet of the protective film forming and dicing sheet.

The protective film is generally composed of a black resin composition. When laser marking is applied to such a protective film, the protective film is generally good even if the laser output is relatively weak. Can be printed.

JP 2006-140348 A

In recent years, it has been proposed to apply laser marking to a semiconductor wafer or glass plate as a workpiece. As described above, when laser marking is performed on an inorganic material, printing cannot be performed satisfactorily, and the formed printing becomes rough, so that the problem of low printing accuracy tends to occur.

In addition, when laser marking is performed on an inorganic material as described above, it is necessary to relatively increase the output of the laser, which makes it easy to burn the base material of the dicing sheet. If it becomes so, the light transmittance of the burned part will fall and it will become impossible to visually recognize the print formed on the work. In addition, when the pressure-sensitive adhesive layer of the dicing sheet is UV curable, when the pressure-sensitive adhesive layer is UV-cured, the UV transmittance at the burned portion of the substrate is deteriorated. As a result, the pressure-sensitive adhesive layer of the portion However, there is a problem of adhesive residue that cannot be cured sufficiently and the adhesive is attached to the picked-up chip.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a workpiece processing sheet that is excellent in laser marking properties and resistant to laser light.

In order to achieve the above object, first, the present invention is a workpiece processing sheet comprising at least a base material and an adhesive layer laminated on the first surface side of the base material, The arithmetic average roughness (Ra) on the second surface of the substrate is 0.01 μm or more and 0.4 μm or less, and the maximum height roughness (Rz) on the second surface of the substrate is 0.00. Provided is a workpiece processing sheet characterized by having a light transmittance at a wavelength of 532 nm of the substrate of not less than 01 μm and not more than 2.5 μm and not less than 40% (Invention 1).

In the said invention (invention 1), since the physical property of a base material is as above, the laser beam used for laser marking, especially a laser beam with a wavelength of 532 nm is easy to permeate | transmit a base material and by extension, the workpiece | work sheet | seat. It will be a thing. Thereby, printing by laser marking can be performed satisfactorily on the workpiece, and high-precision printing can be formed. In addition, it is difficult for the substrate to absorb the energy of the laser beam, and the substrate is prevented from being burned and printed. Therefore, there is no decrease in light transmittance due to the burning of the base material, and the print formed on the work can be satisfactorily viewed through the work processing sheet.

In the above invention (Invention 1), it is preferable that the light transmittance at a wavelength of 400 nm of the substrate is 40% or more (Invention 2).

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

The work processing sheet according to the above invention (Inventions 1 to 3) is preferably used for an application including a step of performing laser marking on 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 workpiece 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 is excellent in laser marking properties and resistant to laser light.

It is sectional drawing of the sheet | seat for workpiece | work processing which concerns on one Embodiment of this invention. It is sectional drawing which shows the usage example of the workpiece | 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 workpiece processing sheet according to an embodiment of the present invention. As shown in FIG. 1, a workpiece processing sheet 1 according to the present embodiment includes a base material 2, a pressure-sensitive adhesive layer 3 laminated on the first surface side (upper side in FIG. 1) of the base material 2, And a release sheet 6 laminated on the pressure-sensitive adhesive layer 3. The release sheet 6 is peeled and removed when the workpiece processing sheet 1 is used, and protects the pressure-sensitive adhesive layer 3 until that time, and may be omitted from the workpiece processing sheet 1 according to the present embodiment. Here, the surface of the base material 2 on the pressure-sensitive adhesive layer 3 side is referred to as a “first surface”, and the opposite surface (the lower surface in FIG. 1) is referred to as a “second surface”.

As an example, the workpiece processing sheet 1 according to the present embodiment is used to hold a workpiece in a laser marking step and a dicing step on a semiconductor wafer or a glass plate as a workpiece, but is not limited thereto. .

The laser marking in the present embodiment is also applicable to a member made of an organic material such as a protective film, an adhesive layer, or a surface layer of a package, as well as a member made of an inorganic material such as a semiconductor wafer or a glass plate. It becomes.

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

1. Components for Workpiece Processing Sheet (1) Substrate (1-1) Physical Properties Arithmetic average roughness (Ra) on the second surface of the substrate 2 (hereinafter sometimes referred to as “back surface of the substrate 2”) 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 substrate 2 at a wavelength of 532 nm is 40% or more. The arithmetic average roughness (Ra) and the maximum height roughness (Rz) in this specification are measured based on JIS B0601: 1999. The light transmittance in this specification is measured by a direct light receiving method using a spectrophotometer as a measuring instrument. In either case, details of the measurement method are as shown in the test examples described later.

When the arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the second surface of the substrate 2 are in the above range, and the light transmittance at a wavelength of 532 nm of the substrate 2 is as described above, Laser light used for laser marking, in particular laser light having a wavelength of 532 nm, can easily pass through the base material 2 and thus the workpiece processing sheet 1. Thereby, it is possible to satisfactorily perform printing by laser marking on the workpiece, and to form highly accurate printing. Further, it is difficult for the substrate 2 to absorb the energy of the laser beam, and it is suppressed that the substrate 2 is burned 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 viewed well 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 through the substrate 2, the ultraviolet light reaches the pressure-sensitive adhesive layer 3 without any problem. The pressure-sensitive adhesive layer 3 is cured well. For this reason, it is difficult for the adhesive residue to adhere to the picked-up chip. That is, the workpiece processing sheet 1 according to the present embodiment is excellent in laser marking properties and resistant to laser light.

Furthermore, when the base material 2 satisfies the above-described physical properties, the transmittance of the laser beam used in stealth dicing is improved, and the stealth dicing processability is excellent.

In addition, since the arithmetic average roughness (Ra) and the maximum height roughness (Rz) of the second surface of the substrate 2 are in the above ranges, blocking of the workpiece processing sheet 1 can also be suppressed. That is, it is possible to satisfactorily feed the workpiece processing sheet 1 from the winding body, and it is difficult to cause peeling at an unintended interface during feeding.

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

Also, the maximum height roughness (Rz) on the back surface of the substrate 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 substrate 2 prevents 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.

Since the pressure-sensitive adhesive layer 3 is laminated on the first surface of the base material 2 (hereinafter sometimes referred to as “the front surface of the base material 2”), the unevenness on the front surface of the base material 2 is filled with the pressure-sensitive adhesive layer 3. The arithmetic average roughness (Ra) and the maximum height roughness (Rz) of the front surface of the substrate 2 are not particularly limited. However, since the unevenness | corrugation of the front surface of the base material 2 may not be filled with the adhesive layer 3 when those values are too large, arithmetic mean roughness (Ra) of the front surface of the base material 2 is set as an upper limit. The thickness is preferably 2.5 μm or less. The lower limit value of the arithmetic average roughness (Ra) of the front surface of the substrate 2 is not particularly limited, but is usually 0.01 μm or more in view of the film forming method. For the above reason, the maximum height roughness (Rz) of the front surface of the substrate 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 substrate 2 is not particularly limited, but is usually 0.01 μm or more in terms of the film forming method.

As described above, the light transmittance of the substrate 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 laser light (especially laser light with a wavelength of 532 nm) mainly used in laser marking is absorbed by the base material 2 and the base material 2 is easily burnt. Become. In addition, the upper limit of the light transmittance at a wavelength of 532 nm is not particularly limited, and may be 100%.

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

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

(1-2) Thickness The thickness of the substrate 2 is not particularly limited as long as it can function properly in each process in which the workpiece processing sheet 1 is used. Specifically, the thickness of the substrate 2 is preferably 20 μm or more, particularly preferably 25 μm or more, and more preferably 50 μm or more. Further, the thickness of the substrate 2 is preferably 450 μm or less, particularly preferably 400 μm or less, and more preferably 350 μm or less. The workability of a workpiece | work and the transmittance | permeability of a laser beam can be favorably maintained because the thickness of the base material 2 exists in the said range.

(1-3) Material The substrate 2 is preferably composed of a resin film. Specific examples of the resin film constituting the substrate 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. Polyolefin films such as copolymer film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film; ethylene-vinyl acetate copolymer film, ethylene- (meth) acrylic acid copolymer Polymer films, ethylene copolymer films such as ethylene- (meth) acrylate copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films ; Polyurethane film; polyimide film; polystyrene films; polycarbonate film, polyethylene terephthalate film, a polyester film such as polyethylene terephthalate and polybutylene terephthalate film and a fluorine resin film. In addition, 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 or different types of the above films are laminated. In addition, “(meth) acrylic acid” in the present specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

Among these, polyolefin film, polyvinyl chloride film and ethylene copolymer film are preferable. Among the polyolefin-based films, a polyethylene film is preferable, and a low density polyethylene (LDPE) film is particularly preferable. Further, among the polyvinyl chloride films, a polyvinyl chloride film is particularly preferable, and among the ethylene copolymer films, an ethylene- (meth) acrylic acid copolymer film is particularly preferable. According to these resin films, the above-described physical properties are easily satisfied. These resin films are also preferable from the viewpoints of expandability, work stickability, chip peelability, and the like.

For the purpose of improving the adhesiveness with the pressure-sensitive adhesive layer 3 laminated on the surface of the resin film, one surface or both surfaces may be subjected to a surface treatment such as an oxidation method or a concavo-convex method or a primer treatment as 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, ultraviolet irradiation treatment, and the like. Examples include a thermal spraying method.

In addition, the base material 2 may contain various additives, such as a coloring agent, a flame retardant, a plasticizer, an antistatic agent, a lubricant, a filler, in the said resin film.

(1-4) Manufacturing Method The resin film constituting the substrate 2 can be manufactured by a manufacturing method corresponding to the type of the resin film, but is mainly manufactured by an extrusion T-die method. In order to produce a resin film having the arithmetic average roughness (Ra), maximum height roughness (Rz), and light transmittance described above, it is necessary to prevent air (bubbles) from being involved when the resin film is formed. There is. For example, by performing extrusion molding under reduced pressure, under vacuum, or the like, the entrainment of such air can be suppressed and a resin film having no bubble trace can be produced. Moreover, the resin film without a bubble trace can be manufactured also by adjusting the surface roughness of each process rolls, such as a cooling roll at the time of film forming. However, the method for producing the resin film having the arithmetic average roughness (Ra), the maximum height roughness (Rz), and the light transmittance described above is not limited thereto.

(2) Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 3 included in the workpiece processing sheet 1 according to the present embodiment may be formed of an active energy ray non-curable pressure sensitive adhesive or may be formed of an active energy ray curable pressure sensitive adhesive. May be. As the active energy ray non-curable adhesive, those having desired adhesive strength and removability are preferable. For example, acrylic adhesive, rubber adhesive, silicone adhesive, urethane adhesive, polyester adhesive An agent, a polyvinyl ether adhesive, etc. can be used. Among these, an acrylic pressure-sensitive adhesive that can effectively prevent the workpiece or workpiece from falling off in a dicing step or the like is preferable.

On the other hand, since the adhesive strength of the active energy ray-curable adhesive is reduced by irradiation with the active energy ray, it is easy to irradiate the active energy ray when it is desired to separate the workpiece or the workpiece and the work processing sheet 1. Can be separated. In the present embodiment, the active energy ray-curable adhesive is preferably an ultraviolet curable adhesive. Thereby, the adhesive residue suppression effect mentioned above will be actualized and 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 curability, or a polymer having no active energy ray curability and an active energy ray. The main component may be a mixture of a curable polyfunctional monomer and / or oligomer.

The case where the active energy ray-curable pressure-sensitive adhesive is mainly composed of a polymer having active energy ray-curability 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 in the side chain (A) It is preferably “active energy ray-curable polymer (A)”. This active energy ray-curable polymer (A) includes 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. ) Is preferably obtained.

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. It is preferable that

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 may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1) include alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group, cycloalkyl (meth) acrylates, and benzyl (meth) acrylates. Is used. Among these, particularly preferred are alkyl (meth) acrylates having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate. 2-ethylhexyl (meth) acrylate or the like is used.

The acrylic copolymer (a1) usually contains 3 to 100% by mass, preferably 5 to 40% by mass of a structural unit derived from the functional group-containing monomer, and is a (meth) acrylic acid ester monomer or its The structural unit derived from the derivative is usually contained in a proportion 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 in a conventional manner. 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 an unsaturated group-containing compound (a2) having a substituent bonded to the functional group, an active energy ray-curable polymer ( A) is obtained.

The substituent of the unsaturated group-containing compound (a2) can be appropriately selected according to the type of 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 an amino group, a carboxyl group or an aziridinyl group. preferable.

In addition, the unsaturated group-containing compound (a2) contains 1 to 5, preferably 1 to 2 active energy ray polymerizable carbon-carbon double bonds per molecule. Specific examples of such unsaturated group-containing compound (a2) include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1- ( Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, polyol compound, and 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.

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), depending on the combination of the functional group and the substituent, the reaction temperature, pressure, solvent, time, presence of catalyst, catalyst Can be selected as appropriate. As a result, the functional group present in the acrylic copolymer (a1) reacts with the substituent in the unsaturated group-containing compound (a2), so that the unsaturated group is contained in the acrylic copolymer (a1). Introduced into the side chain, an active energy ray-curable polymer (A) is obtained.

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 1,500,000, and more preferably 200,000 to 1,000,000. Preferably there is. In addition, the weight average molecular weight (Mw) in this specification is the value of polystyrene conversion measured by the gel permeation chromatography method (GPC method).

Even when the active energy ray-curable pressure-sensitive adhesive is mainly composed of a polymer having active energy ray-curability, the active energy ray-curable pressure-sensitive adhesive is an active energy ray-curable monomer and / or 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 or the like can be used.

Examples of the active energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, 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 Polyfunctional acrylic acid esters such as glycol di (meth) acrylate, dimethyloltricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo ( Data) acrylate, and the like.

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. The content is preferably mass%, particularly preferably 20 to 60 mass%.

Here, when using an ultraviolet ray as an active energy ray for curing the active energy ray-curable resin composition, it is preferable to add a photopolymerization initiator (C). By use, 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, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4 6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-me Le-1- [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more.

The photopolymerization initiator (C) is an active energy ray-curable polymer (A) (when an active energy ray-curable monomer and / or oligomer (B) is blended, the active energy ray-curable polymer (A) ) And the active energy ray-curable monomer and / or oligomer (B) in a total amount of 100 parts by mass) A quantity in the range of 0.1 to 10 parts by weight, in particular 0.5 to 6 parts by weight with respect to 100 parts by weight. Is preferably used.

In the active energy ray-curable pressure-sensitive adhesive, in addition to the above components, other components may be appropriately blended. Examples of other components include a polymer component or oligomer component (D) that does not have active energy ray curability, and a crosslinking agent (E).

Examples of the polymer component or oligomer component (D) having no active energy ray curability include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and have a weight average molecular weight (Mw) of 3,000 to 2.5 million. Polymers or oligomers are preferred.

As the crosslinking agent (E), a polyfunctional compound having reactivity with the 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, A reactive phenol resin etc. can be mentioned.

By blending these other components (D) and (E) in the active energy ray-curable pressure-sensitive adhesive, tackiness and peelability before curing, strength after curing, adhesion to other layers, 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, the case where the active energy ray-curable pressure-sensitive adhesive is mainly composed of a mixture of a polymer component having no active energy ray curability and an active energy ray-curable polyfunctional monomer and / or oligomer will be described below. .

As the polymer component having no active energy ray curability, for example, the same components 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 more preferably 30 to 80% by mass.

As the active energy ray-curable polyfunctional monomer and / or oligomer, the same one as the above-mentioned component (B) is selected. The blending ratio of the polymer component having no active energy ray curability and the active energy ray curable polyfunctional monomer and / or oligomer is 10 to 150 mass parts of the polyfunctional monomer and / or oligomer with respect to 100 parts by mass of the polymer component. Part is preferable, and in particular, 25 to 100 parts by weight is preferable.

Also in this case, the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately blended as described above.

The thickness of the pressure-sensitive adhesive layer 3 is not particularly limited as long as it can function properly in each process in which the workpiece processing sheet 1 is used. Specifically, the thickness 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 other layers (such as a die bonding film) are laminated on the pressure-sensitive adhesive layer 3, The release sheet 6 may be laminated on the other layer.

The configuration of the release sheet 6 is arbitrary, and examples include a plastic film that has been subjected to a release treatment 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, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, a silicone-based material that is inexpensive and provides stable performance 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 workpiece processing sheet 1 according to the present embodiment, an adhesive layer is laminated on the surface of the pressure-sensitive adhesive layer 3 opposite to the substrate 2 (hereinafter sometimes referred to as “pressure-sensitive surface”). May be. In this case, the workpiece processing sheet 1 according to the present embodiment can be used as a dicing die bonding sheet by including the adhesive layer. In such a dicing die-bonding sheet, a workpiece is attached to the surface of the adhesive layer opposite to the pressure-sensitive adhesive layer, and the adhesive layer separated into individual pieces is obtained by dicing the adhesive layer together with the workpiece. Stacked chips can be obtained. The chip can be easily fixed to an object on which the chip is mounted by the separated adhesive layer. As a 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-cured) thermosetting adhesive component, or the like is used. It is preferable.

Further, in the workpiece 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 workpiece 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, the workpiece was applied to the surface of the protective film forming layer opposite to the pressure-sensitive adhesive layer, and the protective film forming layer was diced together with the workpiece. A chip on which a protective film forming layer is laminated can be obtained. As the material to be cut, one having a circuit formed on one side is preferably used. 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 individual protective film forming layers are cured at a predetermined timing (preferably before the dicing step), whereby a protective film having sufficient durability can be formed on the workpiece 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 workpiece itself but the adhesive layer or the protective film. However, even in these cases, the excellent effects of laser marking and laser light resistance described above can be obtained.

2. Manufacturing method of work processing sheet In order to manufacture the work processing sheet 1, as an example, a pressure-sensitive adhesive containing a pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3 on the release surface of the release sheet 6 and, if desired, a solvent. A pressure-sensitive adhesive layer 3 is formed by applying a layer coating agent and drying it. Then, the base material 2 is crimped | bonded to the exposed surface of the adhesive layer 3, and the workpiece | work process sheet 1 which consists of the base material 2, the adhesive layer 3, and the peeling sheet 6 is obtained.

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. Thereby, the adhesive force with respect to jigs, such as a ring frame, can be maintained highly.

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 shape corresponding to a workpiece (semiconductor wafer). In this case, an excess portion generated by the half cut may be removed as appropriate.

3. Method for Using Workpiece Processing Sheet The workpiece processing sheet 1 according to this embodiment is preferably used for dicing. Examples of the dicing include blade dicing, stealth dicing, plasma dicing, laser dicing, and water dicing. Among these, blade dicing and stealth dicing are preferable. Examples of the work include, but are not limited to, a semiconductor wafer made of an inorganic material, a glass plate, and various packages.

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

First, the wound roll-shaped workpiece processing sheet 1 is fed out while peeling the release sheet 6, and as shown in FIG. 2, the semiconductor wafer 7 and the ring frame are placed on the adhesive layer 3 of the workpiece processing sheet 1. 8 is pasted. Thereby, a laminated structure (hereinafter sometimes referred to as “laminated structure L”) having a configuration in which the semiconductor wafer 7 and the ring frame 8 are laminated on the surface of the workpiece processing sheet 1 on the pressure-sensitive adhesive layer 3 side is obtained. .

Next, the laminated structure L is subjected to a laser marking process. Specifically, using a laser irradiation apparatus for laser marking, the semiconductor wafer 7 is irradiated with laser light through the workpiece processing sheet 1 to perform desired printing on the semiconductor wafer 7. As the laser light, laser light having a wavelength of 532 nm is mainly used.

In the workpiece processing sheet 1 according to this embodiment, since the physical properties of the base material 2 are set as described above, the laser beam is easily transmitted, and thus the printing by laser marking is favorably performed on the workpiece. It is possible to perform printing with high accuracy. Moreover, since the energy of the laser beam is hardly absorbed in the base material 2, it is suppressed that the base material 2 is 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 viewed well through the work processing sheet 1.

Next, the laminated structure L is subjected to a dicing process. In the case of blade dicing, chips are obtained by cutting and dividing the semiconductor wafer 7 using a dicing blade. Thereafter, by performing an expanding process for extending the workpiece processing sheet 1, the interval between the chips is widened so that it can be easily picked up in the next pickup process.

On the other hand, in the case of stealth dicing, a laser beam is irradiated to the semiconductor wafer 7 via the workpiece processing sheet 1 using a laser beam splitting apparatus (laser dicer) for dividing the semiconductor wafer 7. A modified layer is formed on the substrate. In addition, since the physical properties of the base material 2 are set as described above, the laser light transmittance by the laser dicer is also excellent. Thereafter, an expanding process for extending the workpiece processing sheet 1 is performed to apply a force (tensile force in the main surface direction) to the semiconductor wafer 7. As a result, the semiconductor wafer 7 adhered to the workpiece processing sheet 1 is divided to obtain chips.

Next, a chip is picked up from the workpiece processing sheet 1 using a pickup device. Here, when the adhesive layer 3 of the work processing sheet 1 is made of an active energy ray-curable adhesive, the active energy ray is applied to the adhesive layer 3 via the base material 2 before the pickup. Is preferably irradiated. Thereby, the adhesive force of the adhesive layer 3 can be reduced, and the chip can be easily picked up. As the active energy ray, an ultraviolet ray, an electron beam or the like is usually used, and an ultraviolet ray that is easy to handle is 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. Further, the amount of ultraviolet light is preferably 2000 mJ / cm ² or less, particularly preferably 1000 mJ / cm ² or less, and more preferably 500 mJ / cm ² or less.

As described above, since the burning of the base material 2 due to laser marking is suppressed, the pressure-sensitive adhesive layer 3 is excellent even when the adhesive layer 3 is irradiated with ultraviolet rays through the base material 2 as described above. Harden. For this reason, it is difficult for the adhesive residue to adhere to the picked-up chip.

The embodiment described above is described for facilitating understanding of the present invention, and is 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, other layers may be provided between the base material 2 and the pressure-sensitive adhesive layer 3 in the workpiece 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 more specifically 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) Fabrication of base material A low-density polyethylene resin composition was extruded by a small T-die extruder (product name “Labo Plast Mill”, manufactured by Toyo Seiki Seisakusho Co., Ltd.) and formed from a resin film having a thickness of 80 μm. A material was prepared. When 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, it was as shown in Table 1.

(2) Preparation of coating agent for pressure-sensitive adhesive layer To a copolymer obtained by copolymerizing 72 parts by mass of butyl acrylate and 28 parts by mass of 2-hydroxyethyl acrylate (HEA), methacryloyloxyethyl isocyanate (MOI) was added. The active energy ray-curable acrylic polymer (weight average molecular weight 500,000) having an active energy ray-polymerizable group in the side chain was obtained by reacting 80 mol% with respect to the copolymer HEA.

With respect to 100 parts by mass of the above active energy ray-curable acrylic polymer (solid content concentration; hereinafter the same), 3.0 parts by mass of a photopolymerization initiator (manufactured by BASF, product name “Irgacure 184”) and an isocyanate compound (Tosoh Corporation make, product name "Coronate L") 1.0 mass part was mix | blended, and the coating agent for adhesive layers was obtained by diluting with a solvent.

(3) Manufacture of Workpiece Processing Sheet A release sheet (product name “SP-PET381031”, manufactured by Lintec Corporation) having a silicone release agent layer formed on one side of a 38 μm thick polyethylene terephthalate film was prepared. On the release surface of the release sheet, the aforementioned adhesive layer coating agent was applied with a knife coater and dried to form an adhesive layer having a thickness of 10 μm. On the pressure-sensitive adhesive layer, the front surface of the base material prepared above was stacked and bonded together to obtain a laminate composed of the base material (80 μm) / pressure-sensitive adhesive layer (10 μm) / release sheet.

The above-obtained laminate 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 using a small T-die extruder (product name “Lab Plast Mill”, manufactured by Toyo Seiki Seisakusho Co., Ltd.) to prepare a substrate made of a resin film having a thickness of 80 μm. When 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, it 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 resin composition of an ethylene- (meth) acrylic acid copolymer is extruded by a small T-die extruder (product name “Lab Plast Mill”, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and is formed of a resin film having a thickness of 80 μm. A material was prepared. When 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, it was as shown in Table 1.

[Comparative Example 1]
A resin composition of an ethylene- (meth) acrylic acid copolymer is extruded by a small T-die extruder (product name “Lab Plast Mill”, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and is formed of a resin film having a thickness of 80 μm. A material was prepared. When 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, it was as shown in Table 1.

[Comparative Example 2]
The polyethylene resin composition was extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “Laboplast Mill”) to prepare a substrate made of a resin film having a thickness of 110 μm. When 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, it was as shown in Table 1.

[Comparative Example 3]
The resin composition of low density polyethylene was extruded using 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. When 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, it was as shown in Table 1.

[Test Example 1] <Measurement of surface roughness of substrate>
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 were measured using a contact surface roughness meter (product name, manufactured by Mitutoyo Corporation). "SV3000S4") was measured according to JIS B0601: 1999 under the following measurement conditions. The results are shown in Table 1.
[Measurement condition]
Evaluation length: 10mm
Standard length: 2.5mm
Scanning speed: 1.0mm / sec
Cut-off value: 0.25mm

[Test Example 2] <Measurement of light transmittance>
About the base material produced in the Example and the comparative example, the light transmittance was measured by a direct light receiving method using an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, product name “UV-3600”). The light transmittance (%) at 400 nm, 532 nm and 800 nm was extracted. The results are shown in Table 1.

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

Using a laser marker (EO TECHNICS, product name “CSM300M”), a silicon wafer is irradiated with laser light having a wavelength of 532 nm through a workpiece processing sheet, and printing is performed on the silicon wafer by laser marking (character size: 0) 2 mm × 0.3 mm, character spacing: 0.3 mm, number of characters: 20 characters).

Thereafter, the workpiece processing sheet was peeled from the silicon wafer, and the print formed on the silicon wafer was confirmed using a digital microscope (manufactured by Keyence Corporation, product name “Digital Microscope VHX-1000”, magnification: 100 ×). . As a result, the print had no roughness and was formed with high accuracy ◎, the print had a slight roughness, but the print was formed with a certain degree of accuracy ◯, the print was rough and the accuracy Was 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 workpiece processing sheet, and printing was performed on the silicon wafer. Thereafter, the workpiece processing sheet was peeled from the silicon wafer, and it was visually confirmed whether or not the substrate of the workpiece processing sheet was burned (printed) by laser light. As a result, the case where the substrate was not burned (printed) was evaluated as ◯, and the case where the substrate was burned (printed) was evaluated as x. The results are shown in Table 1.

As can be seen from Table 1, the work processing sheets obtained in the examples were excellent in laser marking properties and resistant to laser light.

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

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

Claims

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