TWI797309B - Laser marking method and sheet for workpiece processing - Google Patents

Abstract

A workpiece processing sheet 1, which is a workpiece processing sheet 1 having at least a substrate 2 and an adhesive layer 3 laminated on the first surface side of the substrate 2, wherein the second surface of the substrate 2 The arithmetic average roughness (Ra) of the substrate 2 is not less than 0.01 μm and not more than 0.4 μm, and the maximum height roughness (Rz) on the second surface of the substrate 2 is not less than 0.01 μm and not more than 2.5 μm. The light rate is above 40%. Such a workpiece processing sheet 1 is not only excellent in laser marking properties, but also resistant to laser light.

Description

Laser marking method and sheet for workpiece processing

The present invention relates to a sheet for workpiece processing, and particularly relates to a sheet for workpiece processing suitable for laser marking of a workpiece.

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

Therefore, there are many cases in which a protective film made of a hard organic material for protecting the semiconductor wafer is formed on the inner surface side of the semiconductor wafer. Then, for example, Patent Document 1 discloses a sheet for protective film formation and dicing 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 and dicing sheet, after forming a protective film on a semiconductor wafer, dicing can be continued to obtain a semiconductor wafer with a protective film.

Moreover, the said dicing sheet itself has a base material and the adhesive layer provided in one surface. As the adhesive of the adhesive layer, in order to improve the releasability of the semiconductor wafer with a protective film when picking up (pick up), it is possible to use an ultraviolet curable adhesive that reduces the adhesive force by ultraviolet irradiation.

Usually, the said protective film is printed in order to display the product number etc. of this semiconductor wafer. This printing method is generally a laser marking method in which a protective film is irradiated with laser light. When laser marking is performed on a protective film, laser light is irradiated to a protective film through the dicing sheet of the sheet|seat for protective film formation and dicing.

The above-mentioned protective film is generally made of a black resin composition. When laser marking is performed on such a protective film, generally speaking, even if the laser output is weak, the protective film can be well printed. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2006-140348

[Problem to be solved by the invention]

In recent years, there have been proposals to perform laser marking on semiconductor wafers, glass plates, etc., which are workpieces. In the case of performing laser marking on such an inorganic material, there are likely to be problems in that printing cannot be performed satisfactorily, the formed printed characters become rough, and the precision of printed characters decreases.

In addition, when laser marking is performed on an inorganic material as described above, the output of the laser needs to be large, so the base material of the dicing sheet is easily burnt. Then, the light transmittance of the scorched portion decreases, so that the printed characters formed on the workpiece cannot be seen well. In addition, when the adhesive layer of the dicing sheet is ultraviolet curable, when the adhesive layer is cured by ultraviolet light, the ultraviolet transmittance of the burnt part of the base material becomes poor, and as a result, the adhesive layer of this part cannot be fully cured. , resulting in the problem that the adhesive adheres to the residual paste residue of the picked-up wafer.

The present invention is made in view of the above-mentioned actual situation, and an object of the present invention is to provide a sheet for workpiece processing that is excellent in laser marking properties and resistant to laser light. [Technical means to solve the problem]

In order to achieve the above object, first, the present invention provides a sheet for workpiece processing, which is a sheet for workpiece processing having at least a base material and an adhesive layer laminated on the first surface side of the base material, characterized in that , 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 0.01 μm or more and 2.5 μm or less , The light transmittance of the substrate at a wavelength of 532 nm is 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, especially the laser light with a wavelength of 532 nm, easily passes through the base material and even the workpiece processing sheet. Therefore, it is possible to satisfactorily perform laser marking on the workpiece, and to form highly precise printed characters. In addition, the energy of the laser light is hardly absorbed in the base material, and it is possible to prevent the base material from being scorched and printed. Therefore, there is no reduction in light transmittance due to burning of the base material, and the printed characters formed on the workpiece can be seen favorably through the workpiece processing sheet.

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

In the above inventions (Inventions 1 and 2), it is preferable that the light transmittance of the substrate at a wavelength of 800 nm is 45% or more (Invention 3).

The workpiece processing sheet in the above inventions (Inventions 1 to 3) is preferably used in a use including a step of laser marking a workpiece through the workpiece processing sheet (Invention 4).

The sheet for workpiece processing in the above inventions (Inventions 1 to 4) is preferably used for cutting (Invention 5).

The sheet for workpiece processing in the above invention (Invention 5) is preferably used for stealth dicing (Invention 6). [Effect of Invention]

The workpiece processing sheet of the present invention not only has excellent laser marking properties, but also has resistance to laser light.

Embodiments of the present invention will be described below. Fig. 1 is a cross-sectional view of a sheet for workpiece processing according to an embodiment of the present invention. As shown in FIG. 1, the workpiece processing sheet 1 of this embodiment has a base material 2, an adhesive layer 3 laminated on the first surface side of the base material 2 (upper side in FIG. 1 ), and a laminated layer. The release sheet 6 on the adhesive layer 3 is formed. The peeling sheet 6 is to be peeled and removed when the workpiece processing sheet 1 is used to protect the adhesive layer 3 until then, and it can also be omitted in the workpiece processing sheet 1 of this embodiment. Here, the surface on the side of the adhesive layer 3 in the base material 2 is referred to as a "first surface", and the surface on the opposite side (the lower surface in FIG. 1 ) is referred to as a "second surface".

The workpiece processing sheet 1 of the present embodiment is used as an example to maintain the workpiece in the laser marking step and cutting step of the semiconductor wafer, glass plate, etc. as the workpiece, but is not limited to this.

In addition, in the laser marking of the present embodiment, in addition to members made of inorganic materials such as semiconductor wafers and glass plates, the protective film, adhesive layer, etc., or the surface layer of the package, etc., are laminated. Components made of organic materials can also be objects.

The workpiece processing sheet 1 of this embodiment is usually formed into a long strip and rolled into a roll, and used in a roll-to-roll manner.

1. Constituent members of sheets for workpiece processing (1) Substrate (1-1) Physical properties The arithmetic mean roughness (Ra) of the second surface of the base material 2 (hereafter 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 More than μm and less than 2.5 μm. In addition, the light transmittance of the substrate 2 at a wavelength of 532 nm is 40% or more. The arithmetic mean roughness (Ra) and the maximum height roughness (Rz) in this specification are those measured based on JISB0601:1999. In addition, the light transmittance in this specification is measured by the direct light receiving method using a spectrophotometer as a measuring instrument. The details of any of the measurement methods are shown in the test examples described later.

The arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the second surface of the substrate 2 are within the above-mentioned range, and the light transmittance of the substrate 2 at a wavelength of 532 nm is within the above-mentioned range. The laser light used, especially the laser light with a wavelength of 532 nm, easily passes through the substrate 2 and even the sheet 1 for workpiece processing. Therefore, it is possible to satisfactorily perform laser-marked printing on the workpiece, and to form highly precise printed characters. In addition, the energy of the laser light in the base material 2 is hardly absorbed, and it is possible to suppress the base material 2 from being scorched and printed. Therefore, there is no decrease in translucency due to burning of the base material 2 , and the printed characters formed on the workpiece can be visually recognized through the workpiece processing sheet 1 well. Furthermore, when the adhesive layer 3 is composed of an ultraviolet curable adhesive, when ultraviolet rays are irradiated to the adhesive layer 3 through the substrate 2, the ultraviolet rays reach the adhesive layer 3 without any problem, and the adhesive layer 3 Well hardened. Therefore, the problem that the adhesive adheres to the residual paste of the picked-up wafer hardly occurs. That is, the workpiece processing sheet 1 of this embodiment is excellent in laser marking property and has tolerance to laser light.

In addition, when the base material 2 satisfies the above-mentioned physical properties, the transmittance of laser light used in stealth dicing becomes good, and the processability of stealth dicing becomes excellent.

In addition, when the arithmetic average roughness (Ra) and the maximum height roughness (Rz) of the second surface of the base material 2 are in the above-mentioned ranges, blocking of the workpiece processing sheet 1 can also be suppressed. That is, the sheet 1 for workpiece processing can be unwound well, and unintended peeling at the interface is less likely to occur during unwinding.

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

Also, the maximum height roughness (Rz) on the back surface of the substrate 2 is, as described above, 2.5 μm or less, preferably 1.5 μm or less, particularly preferably 0.5 μm or less. When the maximum height roughness (Rz) exceeds 2.5 μm, the irregularities on the back surface of the substrate 2 hinder the transmission of laser light. On the other hand, the lower limit of the maximum height roughness (Rz) is at least 0.01 μm, preferably at least 0.013 μm, particularly preferably at least 0.1 μm, from the viewpoint of preventing blocking.

The adhesive layer 3 is laminated on the first surface of the base material 2 (hereinafter referred to as "the front surface of the base material 2"). The arithmetic mean roughness (Ra) and the maximum height roughness (Rz) of the front surface are not particularly limited. However, once these values are too large, the unevenness on the front side of the base material 2 may not be filled by the adhesive layer 3. The upper limit of the arithmetic mean roughness (Ra) of the front side of the base material 2 is set to It is better to be below 2.5 μm. The lower limit of the arithmetic average roughness (Ra) of the front surface of the base material 2 is not particularly limited, but is usually 0.01 μm or more in terms of a thin film forming method. Also, for the above reasons, the upper limit of the maximum height roughness (Rz) of the front surface of the substrate 2 is preferably 2.5 μm or less. The lower limit of the maximum height roughness (Rz) of the front surface of the base material 2 is not particularly limited, but is generally 0.01 μm or more in terms of a method of forming a thin film.

The light transmittance of the substrate 2 at a wavelength of 532 nm, as described above, is 40% or more, preferably 50% or more, particularly preferably 60% or more, and more preferably 75% or more. When the light transmittance at a wavelength of 532 nm is less than 40%, the energy of the laser light mainly used in laser marking (especially laser light with a wavelength of 532 nm) is absorbed by the substrate 2, and burning of the substrate 2 tends to occur. Also, the upper limit of the light transmittance at a wavelength of 532 nm is not particularly limited, and may be 100%.

In addition, the light transmittance of the substrate 2 at a wavelength of 400 nm is preferably at least 40%, more preferably at least 45%, particularly preferably at least 50%, and more preferably at least 75%. Since the light transmittance at a wavelength of 400 nm is 40% or more, it is easy to transmit visible light. Therefore, through the substrate 2 and even the sheet 1 for workpiece processing, the printed characters formed on the workpiece can be more clearly recognized.

Furthermore, the light transmittance of the substrate 2 at a wavelength of 800 nm is preferably at least 45%, more preferably at least 55%, especially preferably at least 65%, and more preferably at least 75%. Since the light transmittance at a wavelength of 800 nm is 45% or more, it is easy to transmit visible light. Therefore, through the substrate 2 and even the sheet 1 for workpiece processing, the printed characters formed on the workpiece can be more clearly recognized.

(1-2) Thickness The thickness of the base material 2 is not particularly limited as long as it functions appropriately in each step of using the workpiece processing sheet 1 . Specifically, the thickness of the substrate 2 is preferably at least 20 μm, especially preferably at least 25 μm, and more preferably at least 50 μm. Also, the thickness of the substrate 2 is preferably not more than 450 μm, particularly preferably not more than 400 μm, and more preferably not more than 350 μm. When the thickness of the base material 2 is in the above-mentioned range, the processability of the workpiece and the transmittance of laser light can be maintained well.

(1-3) Materials The substrate 2 is preferably made of a resin film. Specific examples of the resin film constituting the substrate 2 include, for example, polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films, Polyolefin films such as polypropylene film, ethylene-propylene copolymer film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norcamphene resin film; Ethylene-based copolymer films such as ethylene-vinyl acetate copolymer films, ethylene-(meth)acrylic acid copolymer films, and ethylene-(meth)acrylate copolymer films; polyvinyl chloride films, vinyl chloride copolymer films, etc. Polyvinyl chloride films; polyester films such as polyethylene terephthalate films and polybutylene terephthalate films; polyurethane films; polyimide films; Styrene film; polycarbonate film; fluororesin film, etc. In addition, modified membranes such as these crosslinked membranes and ionomer membranes can also be used. Furthermore, it may be a laminated film obtained by laminating multiple layers of the above-mentioned films of the same type or different types. In addition, "(meth)acrylic acid" in this specification shows 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 preferred. Among polyolefin films, polyethylene films are preferred, and low-density polyethylene (LDPE) films are particularly preferred. Furthermore, among polyvinyl chloride-based films, polyvinyl chloride films are particularly preferred, and among ethylene-based copolymer films, ethylene-(meth)acrylic acid copolymer films are particularly preferred. According to such a resin film, it is easy to satisfy the said physical property. In addition, these resin films are also preferable from the viewpoints of ductility, workpiece attachability, wafer peelability, and the like.

The above-mentioned resin film may be subjected to surface treatment such as oxidation or embossing or primer treatment on one or both surfaces for the purpose of improving the adhesiveness of the adhesive layer 3 laminated on the surface. Examples of the above-mentioned oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet method), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. , for example, sandblasting, spray processing, etc.

In addition, 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 among the above-mentioned resins.

(1-4) Manufacturing method The resin film constituting the base material 2 can be produced by a production method determined according to the type of the resin film, but it is mainly produced by the T-die method of extrusion molding. In order to manufacture a resin film having the above-mentioned arithmetic mean roughness (Ra), maximum height roughness (Rz) and light transmittance, it is necessary not to entrain air (bubbles) during film formation of the resin film. For example, by extrusion molding under reduced pressure, under vacuum, etc., the above-mentioned air entrainment can be suppressed, and a resin film without traces of air bubbles can be produced. In addition, by adjusting the surface roughness of rolls in each step such as a cooling roll during film formation, a resin film free from bubble marks can also be produced. However, the manufacturing method of the resin film which has said arithmetic mean roughness (Ra), maximum height roughness (Rz), and light transmittance is not limited to these.

(2) Adhesive layer The adhesive layer 3 included in the workpiece processing sheet 1 of this embodiment may be composed of an active energy ray non-curable adhesive or an active energy ray curable adhesive. As active energy ray non-hardening adhesives, those with desired adhesive force and re-peelability are preferable, and acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, etc. can also be used. Ethyl ester adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, an acrylic adhesive that can effectively suppress peeling of workpieces or processed objects in cutting steps and the like is preferable.

On the other hand, since active energy ray-curable adhesives are irradiated with active energy rays, their adhesive force decreases. Therefore, when it is desired to separate the workpiece or processed product from the sheet 1 for workpiece processing, it can be irradiated with active energy rays. easy to separate. In this embodiment, the above-mentioned active energy ray curable adhesive is preferably an ultraviolet curable adhesive. Thereby, the suppression effect of the said residual sludge can be made notable and exhibited.

The active energy ray-curable adhesive constituting the adhesive layer 3 may be a polymer having an active energy ray-curable property as a main component, or may be a polymer that does not have an active energy ray-curable property and an active energy ray-curable adhesive. A mixture of permanent multifunctional monomers and/or oligomers as the main component.

The case where the active energy ray-curable adhesive has an active energy ray-curable polymer as a main component will be described below.

A polymer having active energy ray curability is a (meth)acrylate (co)polymer (A) having an active energy ray curable functional group (active energy ray curable group) introduced into a side chain It is preferably referred to as "active energy ray-curable polymer (A)"). The active energy ray-curable polymer (A) is a (meth)acrylic copolymer (a1) having a functional group-containing monomer unit, and a (meth)acrylic copolymer (a1) having a substituent bonded to the functional group. Those obtained by reacting the base compound (a2) are preferred.

The acrylic copolymer (a1) is composed of a structural unit introduced from a functional group-containing monomer and a structural unit introduced from a (meth)acrylate 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 in the molecule, and a functional group such as a hydroxyl group, an amino group, a substituted amino group, an epoxy group, or the like. good.

As more specific examples of the above-mentioned functional group-containing monomers, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (methyl) ) acrylate, 4-hydroxybutyl (meth)acrylate, etc., these may be used alone or in combination of two or more.

As the (meth)acrylate monomer constituting the acrylic copolymer (a1), alkyl (meth)acrylates, cycloalkyl (meth)acrylates, benzyl base (meth)acrylate. Among these, it is particularly preferable to use an alkyl (meth)acrylate having an alkyl group having 1 to 18 carbon atoms, for example, methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid Propyl ester, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.

The acrylic copolymer (a1) contains the structural unit introduced from the above-mentioned functional group-containing monomer in a ratio of usually 3 to 100 mass%, preferably 5 to 40 mass%, usually 0 to 97 mass%, preferably 60 mass%. The proportion of ~95% by mass contains the structural unit introduced from the (meth)acrylate monomer or its derivative.

The acrylic copolymer (a1) can be obtained by copolymerizing the above-mentioned functional group-containing monomers and (meth)acrylate monomers or their derivatives by the usual method, but other than these monomers, it is also possible to copolymerize Dimethacrylamide, vinyl formate, vinyl acetate, styrene, etc.

The active energy ray-curable type is obtained by reacting the acrylic copolymer (a1) having the above-mentioned functional group-containing monomer unit and the unsaturated group-containing compound (a2) having a substituent bonded to the functional group. Polymer (A).

The substituent which the unsaturated group containing compound (a2) has can be selected suitably according to the kind of the functional group of the functional group containing monomeric unit which acrylic type copolymer (a1) has. For example, when the functional group is a hydroxyl group, an amine 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 amine group, carboxyl group or aziridine group. Aziridinyl is preferred.

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 an unsaturated group-containing compound (a2) include, for example, 2-methacryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, formazan Acryl isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; by diisocyanate compound or polyisocyanate compound (polyisocyanate compound) and hydroxyethyl (meth)acrylic acid The acryl monoisocyanate compound obtained by the reaction of ester; the acryl monoisocyanate compound obtained by the reaction of diisocyanate compound or polyisocyanate compound, polyol (polyol) compound, and hydroxyethyl (meth)acrylate Isocyanate compounds; glycidyl (metha) acrylate (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl) ethyl (meth)acrylate, 2-vinyl- 2-oxazoline (2-vinyl-2-oxazoline), 2-isopropenyl-2-oxazoline, etc.

The unsaturated group-containing compound (a2) is used in a ratio of usually 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 reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and the presence or absence of a catalyst can be appropriately selected according to the combination of functional groups and substituents. type. Therefore, the functional group present in the acrylic copolymer (a1) reacts with the substituent in the unsaturated group-containing compound (a2) to introduce the unsaturated group into the side chain of the acrylic copolymer (a1) to obtain active energy Line hardening type polymer (A).

The weight average molecular weight of the active energy ray-curable polymer (A) thus obtained is preferably at least 10,000, particularly preferably 150,000 to 1.5 million, and more preferably 200,000 to 1 million. In addition, the weight average molecular weight (Mw) in this specification is a polystyrene conversion value measured by colloid permeation chromatography (GPC method).

Even in the case where the active energy ray-curable adhesive contains an active energy ray-curable polymer as a main component, the active energy ray-curable adhesive may further contain an active energy ray-curable monomer and/or an oligosaccharide. Polymer (B).

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

Examples of such active energy ray-curable monomers and/or oligomers (B) include monofunctional acrylic acid such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. Esters, Trimethylolpropane Tri(meth)acrylate, Neopentylthritol Tri(meth)acrylate, Neopentylthritol Tetra(meth)acrylate, Dineopentylthritol Hexa(meth)acrylate Acrylates, 1,4-Butanediol Di(meth)acrylate, 1,6-Hexanediol Di(meth)acrylate, Polyethylene Glycol Di(meth)acrylate, Dimethylol Tris Polyfunctional acrylates such as cyclodecyl di(meth)acrylate, polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate (polyurethane oligo (meth) acrylate), etc.

When preparing the active energy ray-curable monomer and/or oligomer (B), content of the active energy ray-curable monomer and/or oligomer (B) in the active energy ray-curable adhesive , preferably 5-80% by mass, especially 20-60% by mass.

Here, in the case of using ultraviolet rays as the active energy rays for curing the active energy ray-curable resin composition, it is preferable to add a photopolymerization initiator (C), by which the photopolymerization initiator ( The use of C) can reduce the polymerization hardening time and the amount of light exposure.

As the photopolymerization initiator (C), for example, benzophenone (benzophenone), acetophenone (acetophenone), benzoin (benzoin), benzoin methyl ether (benzoin methyl ether), benzoin Benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid methyl Esters (benzoin methyl benzoate), benzoin dimethyl ketal (benzoin dimethyl ketal), 2,4-diethyl thioxanthone (2,4-diethyl thioxanthone), 1-hydroxycyclohexyl phenyl ketone ( 1-hydroxycyclohexyl phenyl ketone), benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, diphenyl ethanedione ( benzil), bibenzyl (dibenzil), diacetyl (diaacetyl), β-chloroanthraquinone (β-chloroanthraquinone), (2,4,6-trimethylbenzyldiphenyl) phosphine oxide ((2, 4,6-trimethylbenzyldiphenyl) phosphine oxide), 2-benzothiazole-N,N-diethyldithiocarbamate (2-benzothiazole-N, N-diethyldithiocarbamate), oligo{2-hydroxy-2-methyl Base-1-[4-(1-propenyl)phenyl]propanone} (oligo {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl] propanone}), 2,2-di Methoxy-1,2-diphenylethane-1-one (2,2-dimethoxy-1,2-diphenylethane-1-one), etc. These may be used individually or in combination of 2 or more types.

The photopolymerization initiator (C), with respect to the active energy ray-curable polymer (A) (in the case of formulating an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable The total amount of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass), 0.1 to 10 parts by mass, especially 0.5 to 6 parts by mass It is better to use the amount in the range.

In the active energy ray-curing adhesive, other components may be appropriately compounded in addition to the above-mentioned components. Examples of other components include, for example, a polymer component or oligomer component (D) that does not have active energy ray curability, a crosslinking agent (E), and the like.

Examples of the polymer component or oligomer component (D) that does not have active energy ray hardening properties include polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, etc., in terms of weight average Polymers or oligomers with a molecular weight (Mw) of 30 million to 2.5 million are preferred.

As the crosslinking agent (E), polyfunctional compounds having reactivity with functional groups contained in the active energy ray-curable polymer (A) and 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, (oxazoline) compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, reactive phenolic resins, etc.

By blending these other components (D) and (E) into the active energy ray-curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesion to other layers, and the storage stability can be improved sex etc. The compounding quantity of these other components is not specifically limited, It can determine suitably within the range of 0-40 mass parts with respect to 100 mass parts of active energy ray hardening type polymers (A).

Next, the case where the active energy ray-curable adhesive contains a mixture of a non-active energy ray-curable polymer component and an active energy ray-curable polyfunctional monomer and/or oligomer as a main component will be described below. .

As the polymer component not having active energy ray curability, for example, the same components as those of the above-mentioned acrylic copolymer (a1) can be used. The content of the non-active energy ray-curable polymer component in the active energy ray-curable resin composition is preferably 20 to 99.9% by mass, particularly preferably 30 to 80% by mass.

As the active energy ray-curable polyfunctional monomer and/or oligomer, the same ones as those of the above-mentioned component (B) can be selected. The compounding ratio of the non-active energy ray-curable polymer component and the active energy ray-curable polyfunctional monomer and/or oligomer is such that, with respect to 100 parts by mass of the polymer component, the polyfunctional monomer and/or oligomer It is preferably 10-150 parts by mass, especially 25-100 parts by mass.

Even in this case, a photopolymerization initiator (C), a crosslinking agent (E), and the like can be appropriately prepared in the same manner as above.

The thickness of the adhesive layer 3 is not particularly limited as long as it can play an appropriate role in each step of using the workpiece processing sheet 1 . Specifically, it is preferably 1-50 μm, particularly preferably 2-30 μm, and more preferably 3-20 μm.

(3) Peeling sheet The release sheet 6 in this embodiment protects the adhesive layer 3 until the workpiece processing sheet 1 is used. In this embodiment, the release sheet 6 is directly laminated on the adhesive layer 3, but it is not limited thereto, and other layers (such as a die-bonding film) may be laminated on the adhesive layer 3, and The release sheet 6 is laminated on this other layer.

The structure of the peeling sheet 6 is arbitrary, and for example, one obtained by peeling a plastic film with a peeling agent or the like can be exemplified. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. membrane. As the release agent, silicones, fluorines, long-chain alkyls, etc. can be used, but among these, silicones that are inexpensive and can provide stable performance are preferable. The thickness of the release sheet is not particularly limited, and is usually about 20 to 250 μm.

(4) Other components In the workpiece processing sheet 1 of this embodiment, an adhesive layer may be laminated on the surface of the adhesive layer 3 opposite to the substrate 2 (hereinafter sometimes referred to as "adhesive surface"). In this case, the workpiece processing sheet 1 of this embodiment can be used as a dicing·die bonding sheet by having the above-mentioned adhesive layer. In such a dicing/die-bonding sheet, a workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer, and the workpiece and the adhesive layer are cut at the same time, thereby obtaining a wafer in which the adhesive layer is stacked into individual pieces. . The chip can be easily fixed to the object on which the chip is mounted by the singulated adhesive layer. As the material constituting the adhesive layer, one containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, or one containing a B-stage (semi-hardened) thermosetting adhesive component, or the like is preferably used.

In addition, in the workpiece processing sheet 1 of the present embodiment, a protective film forming layer may be formed on the adhesive surface of the adhesive layer 3 . In this case, the workpiece processing sheet 1 of this embodiment can be used as a protective film forming and cutting sheet. In such a protective film forming and dicing sheet, a workpiece is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the workpiece and the protective film forming layer are cut at the same time, thereby obtaining a laminated and individualized protective film. Layers are formed on the wafer. As the cut object, it is preferable to use one on which a circuit is formed on one surface. In this case, a protective film forming layer is usually formed on the surface opposite to the surface on which the circuit is formed. The singulated protective film-forming layer is hardened at a predetermined point of time (preferably before the dicing step), whereby a protective film having sufficient durability can be formed on the workpiece or wafer. The protective film forming layer is preferably composed of an uncured curable adhesive.

In the above case, the object of laser marking is not the workpiece itself, but the adhesive layer or protective film. However, even in these cases, the above-mentioned effects of excellent laser marking and laser light resistance can be obtained similarly.

2. Manufacturing method of sheet for workpiece processing As an example of manufacturing the sheet 1 for workpiece processing, the adhesive constituting the adhesive layer 3 and, if necessary, a coating agent for the adhesive layer that further contains a solvent can be coated on the release surface of the release sheet 6, and the resulting The coating agent dries to form the adhesive layer 3 . Thereafter, the base material 2 is pressure-bonded to the exposed surface of the adhesive layer 3 to obtain the workpiece processing sheet 1 composed of the base material 2 , the adhesive layer 3 , and the peeling sheet 6 .

The adhesive layer 3 in this embodiment is preferably one that can be attached to a mold such as a lead frame. In this case, when the adhesive layer 3 is composed of an active energy ray-curable adhesive, it is preferable not to harden the active energy ray-curable adhesive. Thereby, the adhesive force to the die|die, such as a lead frame, can be maintained at a high level.

The laminated body of the base material 2 and the adhesive layer 3 can also be half-cut as required to form a desired shape, for example, a shape corresponding to a circle of the workpiece (semiconductor wafer). In this case, the residual portion produced by half-cutting can be properly removed.

3. How to use the sheet for workpiece processing The workpiece processing sheet 1 of this embodiment is preferably used for cutting. The type of dicing includes, for example, blade dicing, stealth dicing, plasma dicing, laser cutting, water jet cutting, etc. Among these, blade dicing and stealth dicing are preferable. Examples of the workpiece include, for example, semiconductor wafers made of inorganic materials, glass plates, and various packages, but are not limited thereto.

An example of a method of manufacturing wafers from a semiconductor wafer as a workpiece by blade dicing or stealth dicing using the workpiece processing sheet 1 of this embodiment will be described below.

First, the workpiece processing sheet 1 that has been wound into a roll is released one after another while peeling off the release sheet 6, and as shown in FIG. 2, a semiconductor wafer 7 is attached to the adhesive layer 3 of the workpiece processing sheet 1. and lead frame 8. Thereby, a laminated structure having a structure in which the semiconductor wafer 7 and the lead frame 8 are layered on the side of the adhesive layer 3 of the workpiece processing sheet 1 (hereinafter sometimes referred to as "laminated structure L") is obtained.

Then, 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 workpiece processing sheet 1 to perform desired printing on the semiconductor wafer 7 . As the laser light, laser light with a wavelength of 532 nm is mainly used.

In the workpiece processing sheet 1 of this embodiment, since the physical properties of the base material 2 are set as described above, the laser light can easily pass through, so laser marking can be performed well on the workpiece, and high-precision printing can be formed. In addition, since the energy of the laser light is hardly absorbed in the base material 2, burning of the base material 2 can be suppressed. Therefore, there is no decrease in translucency due to burning of the base material 2 , and the printed characters formed on the workpiece can be seen favorably through the workpiece processing sheet 1 .

Then, the laminated structure L is subjected to a cutting step. In the case of blade dicing, the semiconductor wafer 7 is cut and divided using a dicing blade to obtain wafers. Thereafter, a stretching step of stretching the workpiece processing sheet 1 is performed to make it easy to pick up in the subsequent picking up step, thereby widening the gap between wafers.

On the other hand, in the case of stealth dicing, using a laser irradiation device (laser cutter) for dividing processing, laser light is irradiated to the above-mentioned semiconductor wafer 7 through the sheet 1 for workpiece processing, and a modification is formed in the semiconductor wafer 7. stratum. In addition, since the physical properties of the substrate 2 are set as described above, the laser light transmittance of the laser cutting machine is also excellent. Thereafter, by performing an elongation step of elongating the workpiece processing sheet 1 , an acting force (pull force in the main plane inward direction) is applied to the semiconductor wafer 7 . As a result, the semiconductor wafer 7 bonded to the workpiece processing sheet 1 is divided to obtain wafers.

Then, a wafer is picked up from the workpiece processing sheet 1 using a pick-up device. Here, when the adhesive layer 3 of the workpiece processing sheet 1 is composed of an active energy ray-curable adhesive, it is preferable to irradiate the adhesive layer 3 with active energy through the substrate 2 before the above-mentioned pickup. Wire. Thereby, the adhesive force of the adhesive layer 3 can be reduced, and a wafer can be picked up easily. The above-mentioned active energy rays are usually ultraviolet rays, electron rays, etc., and ultraviolet rays, which are easily available, are particularly preferred.

The above-mentioned irradiation of ultraviolet rays can be carried out by means of high-pressure mercury lamps, fusion lamps, xenon lamps, LEDs, etc., and the irradiation amount of ultraviolet rays is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. The amount of ultraviolet light is preferably at least 50 mJ/cm ² , particularly preferably at least 80 mJ/cm ² , and more preferably at least 100 mJ/cm ² . Also, the amount of ultraviolet light is preferably not more than 2000 mJ/cm ² , particularly preferably not more than 1000 mJ/cm ² , and more preferably not more than 500 mJ/cm ² .

As described above, since burning of the base material 2 caused by laser marking is suppressed, the adhesive layer 3 can be cured satisfactorily even when the base material 2 is irradiated with ultraviolet rays to the adhesive layer 3 as described above. Therefore, the problem that residual paste of the adhesive adheres to the picked-up wafer is less likely to occur.

The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Therefore, the requirements disclosed in the above embodiments also include all design changes or equivalents within the technical scope of the present invention.

For example, another layer may be provided between the substrate 2 and the adhesive layer 3 in the workpiece processing sheet 1 , or on the surface of the substrate 2 opposite to the adhesive layer 3 . [Example]

Hereinafter, the present invention will be more specifically described by way of 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 with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a base material composed of a resin film with a thickness of 80 μm. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

(2) Preparation of coating agent for adhesive layer Copolymerize 72 parts by mass of butyl acrylate and 28 parts by mass of 2-hydroxyethyl acrylate (HEA), and make the resulting copolymer and methacryloxyethyl isocyanate (MOI) relative to the copolymer 80 mol% of HEA was reacted 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 a photopolymerization initiator (manufactured by BASF, product name "Irgacure 184") and an isocyanate compound (Tosoh Corp. made, product name "Coronate L") 1.0 parts by mass, and diluted with a solvent to obtain a coating agent for an adhesive layer.

(3) Manufacture of sheets for workpiece processing Prepare a release sheet (manufactured by Lintech, product name "SP-PET 381031") with a silicone-based release agent layer formed on one side of a polyethylene terephthalate film with a thickness of 38 μm. The above-mentioned coating agent for the adhesive layer was applied with a knife coater, and dried to form an adhesive layer with a thickness of 10 μm. On this adhesive layer, the front surface of the base material prepared above was aligned and laminated to obtain a laminate consisting of base material (80 μm)/adhesive layer (10 μm)/release sheet.

The laminate obtained above was half-cut from the base material side to cut the laminate of the base material and the adhesive layer to form a circular workpiece processing sheet with a diameter of 370 mm.

[Example 2] The polyvinyl chloride resin composition was extruded with a small T-shaped extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a base material composed of a resin film with a thickness of 80 μm. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

Except for using the above-mentioned base material, the rest is the same as in Example 1, and a sheet for workpiece processing is produced.

[Example 3] The resin composition of ethylene-(meth)acrylic acid copolymer was extruded with a small T-shaped extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a substrate composed of a resin film with a thickness of 80 μm. material. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

Except for using the above-mentioned base material, the rest is the same as in Example 1, and a sheet for workpiece processing is produced.

[Comparative example 1] The resin composition of ethylene-(meth)acrylic acid copolymer was extruded with a small T-shaped extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a substrate composed of a resin film with a thickness of 80 μm. material. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

Except for using the above-mentioned base material, the rest is the same as in Example 1, and a sheet for workpiece processing is produced.

[Comparative example 2] A polyethylene resin composition was extruded with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a base material composed of a resin film with a thickness of 110 μm. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

Except for using the above-mentioned base material, the rest is the same as in Example 1, and a sheet for workpiece processing is produced.

[Comparative example 3] A low-density polyethylene resin composition was extruded with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") to produce a base material composed of a resin film with a thickness of 80 μm. The surface roughness (arithmetic average roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and is shown in Table 1.

Except for using the above-mentioned base material, the rest is the same as in Example 1, and a sheet for workpiece processing is produced.

[Test Example 1] >Measurement of Surface Roughness of Substrate> For the arithmetic mean roughness (Ra; unit μm) and the maximum height roughness (Rz; unit μm) of the backside of the substrates produced in Examples and Comparative Examples, a contact surface roughness meter (manufactured by Mitutoyo, product name "SV3000S4") was measured in accordance with JIS B0601:1999 under the following measurement conditions. The results are shown in Table 1. [measurement conditions] Evaluation length: 10 mm Base length: 2.5 mm Scanning speed: 1.0mm/sec Cutoff value: 0.25mm

[Test example 2] >Measurement of light transmittance> For the substrates prepared 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"), with an extraction wavelength of 400 nm , 532 nm and 800 nm transmittance. The results are shown in Table 1.

[Test Example 3] >Evaluation of Laser Marking> Using a tape mounter (manufactured by Lintech, 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 attached to The grinding surface of a silicon wafer (diameter: 12 inches, thickness: 350 μm) after #2000 grinding. At the same time, attach the exposed adhesive layer to the lead frame.

Using a laser marking machine (manufactured by EO TECHNICS, product name "CSM300M"), the silicon wafer is irradiated with laser light with a wavelength of 532 nm through the sheet for workpiece processing, and the lettering (text) by laser marking is performed on the silicon wafer. Size: 0.2 mm×0.3 mm, character spacing: 0.3 mm, number of characters: 20 characters).

Thereafter, the workpiece processing sheet was peeled off from the silicon wafer, and the printed characters formed on the silicon wafer were checked 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 the precision was high, and the maker rated it as ◎, the print was a little rough, but the precision was high to a certain extent, and the maker rated it as ○, and the print was rough and the precision was low, and it was rated as ◎. The creator rated it as ╳. The results are shown in Table 1.

[Test Example 4] >Evaluation of Laser Light Resistance> As in Experiment 3, the silicon wafer was irradiated with laser light having a wavelength of 532 nm through the workpiece processing sheet to print on the silicon wafer. Thereafter, the workpiece processing sheet was peeled off from the silicon wafer, and whether or not there was burning (printing) on the base material of the workpiece processing sheet due to laser light was checked visually. As a result, the case where the base material was not burnt (printed) was evaluated as ○, and the case where the base material was burnt (printed) was evaluated as ╳. The results are shown in Table 1.

[Table 1]

As can be seen from Table 1, the workpiece processing sheets obtained in Examples are excellent in laser marking properties and have tolerance to laser light. [Industrial availability]

The workpiece processing sheet of the present invention is suitable for applications including a step of performing laser marking on a workpiece such as a semiconductor wafer or a glass plate through the workpiece processing sheet.

1‧‧‧Sheets for workpiece processing 2‧‧‧Substrate 3‧‧‧adhesive layer 6‧‧‧Peeling sheet 7‧‧‧semiconductor wafer 8‧‧‧Lead frame

Fig. 1 is a cross-sectional view of a sheet for workpiece processing according to an embodiment of the present invention. Fig. 2 is a usage example of the workpiece processing sheet according to an embodiment of the present invention, specifically showing a cross-sectional view of a laminated structure.

1: Sheet for workpiece processing

2: Substrate

3: Adhesive layer

6: Peel off sheet

Claims (6)

A laser marking method for performing laser marking on a workpiece through a workpiece processing sheet, wherein the workpiece processing sheet has at least a base material and a substrate laminated on the first surface side of the base material. The adhesive layer has an arithmetic average roughness (Ra) of 0.01 μm or more and 0.4 μm or less on the second surface of the substrate, and a maximum height roughness (Rz) of 0.01 μm or more on the second surface of the substrate, 2.5 μm or less, the light transmittance of the substrate at a wavelength of 532 nm is 40% or more, and the laser marking is performed using laser light with a wavelength of 532 nm. The laser marking method described in claim 1, wherein the light transmittance of the substrate at a wavelength of 400 nm is above 40%. The laser marking method as described in claim 1, wherein the light transmittance of the base material at a wavelength of 800 nm is 45% or more. The laser marking method as described in any one of items 1 to 3 of the scope of application, wherein the sheet for workpiece processing is used for cutting. The laser marking method described in item 4 of the scope of the patent application, wherein the workpiece processing sheet is used for stealth cutting. A workpiece processing sheet having at least a base material and an adhesive layer laminated on the first surface side of the base material, characterized in that the arithmetic mean of the second surface of the base material The roughness (Ra) is 0.01 μm or more and less than 0.1 μm, the maximum height roughness (Rz) on the second surface of the substrate is 0.01 μm or more and 2.5 μm or less, and the light transmittance of the substrate at a wavelength of 532 nm more than 40%.

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