TW202004876A - Workpiece processing sheet - Google Patents

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 [mu]m and not more than 0.4 [mu]m; the base material 2 has on the second surface thereof a maximum height coarseness (Rz) of not less than 0.01 [mu]m and not more than 2.5 [mu]m; 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

Workpiece processing sheet

The present invention relates to a sheet for workpiece processing, and particularly to a sheet for workpiece processing that is 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 wafer 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 people who form a protective film made of a hard organic material for protecting the semiconductor wafer on the inner surface side of the semiconductor wafer. 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 above protective film is formed on a dicing sheet. According to this sheet for forming a protective film and dicing, after forming a protective film on a semiconductor wafer, dicing can be continued to obtain a semiconductor wafer with a protective film.

In addition, the dicing sheet itself has a base material and an adhesive layer provided on one side thereof. In order to improve the peelability of a semiconductor film with a protective film during pick-up, the adhesive of the adhesive layer may use an ultraviolet-curable adhesive whose adhesive strength is reduced by ultraviolet irradiation.

The protective film is usually printed in order to display the product number of the semiconductor wafer or the like. This printing method is generally a laser marking method in which a protective film is irradiated with laser light. In the case of laser marking the protective film, the protective film is formed by irradiating the protective film with laser light through the cutting sheet of the protective film forming and cutting sheet.

The above-mentioned protective film is generally composed of a black resin composition. In the case of performing laser marking on such a protective film, in general, even if the laser output is weak, it can be well printed on the protective film. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2006-140348

[Problems to be solved by the invention]

In recent years, there have been proposals to perform laser marking on semiconductor wafers, glass plates, etc. as workpieces. In the case of performing laser marking on such an inorganic material, problems such as poor printing cannot be performed, the formed printing becomes coarse and messy, and the precision of the printing becomes low.

In addition, in the case of performing laser marking on an inorganic material as described above, the laser output needs to be large, and therefore, the base material of the dicing sheet is easily burnt. As a result, the light transmittance of the burnt portion is reduced, so that the printing formed on the workpiece cannot be well recognized. In addition, when the adhesive layer of the dicing sheet is ultraviolet-curable, when the adhesive layer is ultraviolet-cured, the ultraviolet transmittance of the scorched portion of the substrate becomes poor, and as a result, the adhesive layer of this portion cannot be sufficiently cured , There is a problem that the adhesive adheres to the residual paste residue of the picked up wafer.

The present invention is formed in view of the above-mentioned actual situation, and aims to provide a sheet for workpiece processing excellent in laser marking property 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 stacked 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 this 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 substrate 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 substrate or even the sheet for processing a workpiece. Therefore, the laser-engraved printing can be performed well on the workpiece, and high-precision printing can be formed. In addition, in the base material, the energy of the laser light is difficult to be absorbed, and the base material can be prevented from being burnt and printed. Therefore, there is no decrease in light transmittance caused by scorching of the base material, and the printing formed on the workpiece can be well recognized by the sheet for processing the workpiece.

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

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

The sheet for workpiece processing in the above inventions (Inventions 1 to 3) is preferably used for the purpose of including the step of laser marking the workpiece via the sheet for workpiece processing (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 sheet for workpiece processing of the present invention not only has excellent laser marking performance, but also has resistance to laser light.

The embodiment 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 the present embodiment includes a substrate 2, an adhesive layer 3 laminated on the first surface side (upper side in FIG. 1) of the substrate 2, and a laminate The release sheet 6 is formed on the adhesive layer 3. The peeling sheet 6 is peeled and removed when the sheet 1 for workpiece processing is used, and the adhesive layer 3 is protected until then, and it may be omitted in the sheet 1 for workpiece processing of the present embodiment. Here, the surface on the adhesive layer 3 side of 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 sheet 1 for workpiece processing of the present embodiment can be exemplified as a user who maintains the workpiece in the laser marking step and the dicing step performed on the semiconductor wafer, glass plate, etc. as the workpiece, but it is not limited to this.

In addition, in the laser marking of the present embodiment, in addition to a member made of an inorganic material such as a semiconductor wafer or a glass plate, a protective film, an adhesive layer, etc., or a surface layer of a package, etc. are laminated Components made of organic materials can also be targeted.

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

1. Constituent members of the sheet for workpiece processing (1) Base material (1-1) Physical properties The arithmetic average roughness (Ra) in the second surface of the base material 2 (hereinafter 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 Above μm, below 2.5 μm. In addition, the light transmittance of the substrate 2 at a wavelength of 532 nm is 40% or more. The arithmetic average roughness (Ra) and maximum height roughness (Rz) in this specification are measured according to JIS B0601:1999. In addition, in this specification, the light transmittance is measured by a direct light receiving method using a spectrophotometer as a measuring instrument. The detailed method of any measurement method is shown in the test example described later.

The arithmetic average roughness (Ra) and the maximum height roughness (Rz) of the second surface of the substrate 2 are within the above range, and the light transmittance of the substrate 2 at a wavelength of 532 nm is within the above range, whereby the laser marking The laser light used, especially the laser light with a wavelength of 532 nm, easily passes through the base material 2 and even the sheet 1 for workpiece processing. Therefore, the workpiece can be well printed with laser marking, and high-precision printing can be formed. In addition, the energy of the laser light in the base material 2 is difficult to be absorbed, and the base material 2 can be prevented from being burnt and printed. Therefore, there is no decrease in the light transmittance caused by the scorching of the base material 2, and the printing formed on the workpiece can be well recognized by the sheet 1 for workpiece processing. Furthermore, in the case where the adhesive layer 3 is composed of an ultraviolet curable adhesive, when the adhesive layer 3 is irradiated with ultraviolet rays through the base material 2, the ultraviolet rays reach the adhesive layer 3 without any problem, and the adhesive layer 3 Good hardening. Therefore, it is difficult for the adhesive to adhere to the residual paste residue of the picked up wafer. That is, the sheet 1 for workpiece processing of the present embodiment is excellent in laser marking ability and resistant to laser light.

In addition, when the base material 2 satisfies the above physical properties, the transparency of laser light used for stealth dicing also becomes good, and it becomes excellent in the workability of stealth dicing.

In addition, the arithmetic average roughness (Ra) and the maximum height roughness (Rz) of the second surface of the base material 2 are in the above-described range, and blocking of the sheet 1 for workpiece processing can also be suppressed. That is, unwinding from the wound body of the sheet 1 for workpiece processing can be performed satisfactorily, and unintentional peeling at the interface hardly occurs at the time of unwinding.

The upper limit of the arithmetic average 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, and particularly preferably less than 0.1 μm. When the arithmetic average roughness (Ra) exceeds 0.4 μm, irregularities on the back surface of the base material 2 hinder 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.

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

The 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"), and the unevenness of the front surface of the base material 2 is buried by the adhesive layer 3, so the The arithmetic mean roughness (Ra) and maximum height roughness (Rz) of the front side are not particularly limited. However, if these values are too large, it may happen that the irregularities on the front surface of the substrate 2 are not buried by the adhesive layer 3, and the upper limit of the arithmetic average roughness (Ra) of the front surface of the substrate 2 is 2.5 μm or less is preferred. The lower limit of the arithmetic mean roughness (Ra) of the front surface of the base material 2 is not particularly limited, but it is usually 0.01 μm or more in the method of forming a thin film. For the above reasons, the upper limit of the maximum height roughness (Rz) of the front surface of the base material 2 is preferably 2.5 μm or less. The lower limit value of the maximum height roughness (Rz) of the front surface of the base material 2 is not particularly limited, but in the film forming method of the thin film, it is usually 0.01 μm or more.

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 still 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 (especially the laser light at a wavelength of 532 nm) mainly used in laser marking is absorbed by the substrate 2 and scorching is likely to occur at the substrate 2. In addition, 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 40% or more, more preferably 45% or more, particularly preferably 50% or more, and further preferably 75% or more. Since the light transmittance at a wavelength of 400 nm is 40% or more, it is easy for visible light to pass through. Therefore, the substrate 2 or the workpiece processing sheet 1 can more clearly recognize the printing formed on the workpiece.

Furthermore, the light transmittance of the substrate 2 at a wavelength of 800 nm is preferably 45% or more, more preferably 55% or more, particularly preferably 65% or more, and further preferably 75% or more. Since the light transmittance at a wavelength of 800 nm is 45% or more, it is easy for visible light to pass through. Therefore, the substrate 2 and the sheet 1 for processing a workpiece can more clearly recognize the printing formed on the workpiece.

(1-2) Thickness The thickness of the base material 2 is not particularly limited as long as it can properly function in each step of using the work processing sheet 1. Specifically, the thickness of the base material 2 is preferably 20 μm or more, particularly preferably 25 μm or more, and further preferably 50 μm or more. The thickness of the substrate 2 is preferably 450 μm or less, particularly 400 μm or less, and more preferably 350 μm or less. When the thickness of the base material 2 is within the above range, the workability of the workpiece and the laser light transmittance can be maintained well.

(1-3) Materials The base material 2 is preferably composed of a resin film. Specific examples of the resin film constituting the base material 2 include polyethylene films such as low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, and high density polyethylene (HDPE) films. Polyolefin film such as polypropylene film, ethylene-propylene 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 film, ethylene-(meth)acrylic acid ester copolymer film and other ethylene-based copolymer films; polyvinyl chloride film, vinyl chloride copolymer film, etc. Polyvinyl chloride film; Polyester film such as polyethylene terephthalate film, polybutylene terephthalate film; Polyurethane film; Polyimide film; Poly Styrene film; polycarbonate film; fluororesin film, etc. In addition, a modified membrane such as such a cross-linked membrane or an ionic polymer membrane can also be used. In addition, it may be a laminated film formed by laminating plural layers of the same type or different types of the above-mentioned films. In addition, in this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same is true for other similar terms.

Among the above, polyolefin-based films, polyvinyl chloride-based films, and ethylene-based copolymer films are preferred. Among the polyolefin-based films, a polyethylene film is preferred, and a low density polyethylene (LDPE) film is particularly preferred. Among the polyvinyl chloride-based films, polyvinyl chloride films are particularly preferred, and among the ethylene-based copolymer films, ethylene-(meth)acrylic acid copolymer films are particularly preferred. According to these resin films, the aforementioned physical properties are easily satisfied. In addition, these resin films are also preferable from the viewpoints of ductility, work attachment property, wafer peelability, and the like.

For the purpose of improving the adhesiveness of the adhesive layer 3 deposited on the surface of the resin film, the surface treatment or the primer treatment using an oxidation method, a bumping method, or the like may be performed on one surface or both surfaces as necessary. Examples of the oxidation method include, for example, corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet type), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. For example, sand blasting method, spraying method, etc.

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

(1-4) Manufacturing method The resin film constituting the base material 2 can be manufactured by a manufacturing method determined according to the type of resin film, but it is mainly manufactured by a T-die method of extrusion molding. In order to produce a resin film having the above-mentioned arithmetic average roughness (Ra), maximum height roughness (Rz), and light transmittance, it is necessary not to involve air (bubble) during the film formation of the resin film. For example, by extrusion molding under reduced pressure, vacuum, or the like, the above-mentioned air entrapment can be suppressed, and a resin film without traces of bubbles can be manufactured. In addition, by adjusting the surface roughness of the roller in each step such as a cooling roller during film formation, a resin film free of traces of air bubbles can also be produced. However, the method of manufacturing the resin film having the above-described arithmetic average 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 the present embodiment may be composed of an active energy ray non-curable adhesive or an active energy ray curable adhesive. As an active energy ray non-hardening adhesive, it is preferable to have a desired adhesive strength and re-peelability, and it can also be used, for example, acrylic adhesive, rubber adhesive, silicone adhesive, amino acid Ethyl ester adhesive, polyester adhesive, polyvinyl ether adhesive, etc. Among these, acrylic adhesives that can effectively suppress the shedding of workpieces or workpieces in cutting steps and the like are preferred.

On the other hand, the active energy ray-curable adhesive has reduced adhesion due to the irradiation of the active energy ray. Therefore, when it is desired to separate the workpiece or the workpiece and the sheet 1 for workpiece processing, the active energy ray can be irradiated through the active energy ray. Easy to separate. In this embodiment, the active energy ray-curable adhesive is preferably an ultraviolet-curable adhesive. Thereby, the above-mentioned residual paste suppression effect can be made prominent and exerted.

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

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

Active energy ray-curable polymer, a (meth)acrylate (co)polymer (A) with a functional group (active energy ray-curable group) having active energy ray hardening introduced into the side chain (there are also below) It is better to call it "active energy ray hardening polymer (A)"). This active energy ray-curable polymer (A) is such that the (meth)acrylic copolymer (a1) having a monomer unit containing a functional group and the substituent having a bond with the functional group contain unsaturation It is preferable that the base compound (a2) is reacted.

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.

As a functional group-containing monomer as a structural unit of the acrylic copolymer (a1), a monomer having a polymerizable double bond in the molecule and functional groups such as a hydroxyl group, an amine group, a substituted amine group, and an epoxy group is good.

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

As the (meth)acrylate monomer constituting the acrylic copolymer (a1), an alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group, a cycloalkyl (meth)acrylate, benzyl can be used Based (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 functional group-containing monomer at a ratio of usually 3 to 100% by mass, preferably 5 to 40% by mass, usually 0 to 97% by mass, preferably 60 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 monomer and the (meth)acrylate monomer or its derivative by a conventional method, but in addition to these monomers, copolymerization is also possible Dimethacrylamide, vinyl formate, vinyl acetate, styrene, etc.

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

The substituent contained in the unsaturated group-containing compound (a2) can be appropriately selected according to the type of the functional group of the functional group-containing monomer unit included in the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amine group, or a substituted amine group, the substituent is preferably an isocyanate group or an epoxy group, and when the functional group is an epoxy group, the substituent is an amine group, a carboxyl group, or aziridine 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, methyl Acryloyl cyanoisocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl) ethyl isocyanate; by diisocyanate compound or polyisocyanate compound and hydroxyethyl (meth) acrylic acid Acryloyl monoisocyanate compound obtained by reaction of ester; Acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with polyol compound and hydroxyethyl (meth)acrylate Isocyanate compounds; glycidyl (metha)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl- 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, etc.

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

In the reaction of the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the reaction temperature, pressure, solvent, time, presence or absence of catalyst, and catalyst can be appropriately selected according to the combination of functional groups and substituents species. 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 in the acrylic copolymer (a1) to obtain active energy Linear hardening polymer (A).

The weight average molecular weight of the active energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly 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 the value converted from the polystyrene measured by the colloidal permeation chromatography method (GPC method).

Even when the active energy ray-curable adhesive is a polymer having active energy ray-curable as a main component, the active energy ray-curable adhesive may further contain active energy ray-curable monomers and/or oligomers Polymer (B).

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

Examples of such active energy ray-curable monomers and/or oligomers (B) include, for example, monofunctional acrylics such as cyclohexyl (meth)acrylate and isobranched (meth)acrylate. Esters, trimethylolpropane tri(meth)acrylate, neopentaerythritol tri(meth)acrylate, neopentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth) Acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethylol tris Multifunctional acrylates such as cyclodecyl di(meth)acrylate, polyester oligo (meth)acrylate, polyurethane oligo(meth)acrylate (polyurethane oligo (meth)acrylate), etc.

In the case of formulating active energy ray-curable monomers and/or oligomers (B), the content of active energy ray-curable monomers and/or oligomers (B) in the active energy ray-curable adhesive , Preferably 5 to 80% by mass, especially 20 to 60% by mass.

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

Examples of the photopolymerization initiator (C) include, for example, benzophenone, acetophenone, benzoin, benzoin methyl ether, and benzoin Benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid, benzoin benzoic acid Ester (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, diphenylethanedione ( benzil), dibenzil, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide ((2, 4,6-trimethylbenzyldiphenyl) phosphine oxide), 2-benzothiazole-N, N-diethyldithiocarbamate, oligo(2-hydroxy-2-methyl Yl-1-[4-(1-propenyl)phenyl]acetone} (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 alone or in combination of two or more.

Photopolymerization initiator (C), relative to active energy ray-curable polymer (A) (in the case of formulating active energy ray-curable monomers and/or oligomers (B), active energy ray-curable type The total weight of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass) 100 parts by mass, 0.1 to 10 parts by mass, especially 0.5 to 6 parts by mass The amount of range is preferably used.

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

Examples of the polymer component or oligomer component (D) having no active energy ray-curable property include, for example, polyacrylate, polyester, polyurethane, polycarbonate, polyolefin, etc. A polymer or oligomer with a molecular weight (Mw) of 30 to 2.5 million is preferred.

As the crosslinking agent (E), polyfunctional compounds can be used, and these polyfunctional compounds have reactivity with functional groups possessed by the active energy ray-curable polymer (A) and the like. Examples of such multifunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, and oxazolines. (oxazoline) compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, reactive phenol resins, etc.

By blending these other components (D) and (E) in an active energy ray-curable adhesive, the adhesion and peelability before curing, the strength after curing, the adhesion to other layers, and storage stability can be improved Sex and so on. The formulation amount of these other components is not particularly limited, and can be appropriately determined within a range of 0 to 40 parts by mass relative to 100 parts by mass of the active energy ray-curable polymer (A).

Then, in the case where the active energy ray-curable adhesive has a mixture of a polymer component that is not active energy ray-curable and an active energy ray-curable polyfunctional monomer and/or oligomer as the main component, the following description .

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

As the active energy ray-curable polyfunctional monomer and/or oligomer, the same as the aforementioned component (B) can be selected. The blending ratio of the polymer component without active energy ray hardening and the polyfunctional monomer and/or oligomer with active energy ray hardening is, based on 100 parts by mass of the polymer component, the polyfunctional monomer and/or oligomer The object is preferably 10 to 150 parts by mass, especially 25 to 100 parts by mass.

Even in this case, as in the above, the photopolymerization initiator (C), crosslinking agent (E), etc. can be appropriately prepared.

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 work processing sheet 1. Specifically, it is preferably 1-50 μm, particularly 2-30 μm, and more preferably 3-20 μm.

(3) Peel off piece In the present embodiment, the release sheet 6 protects the adhesive layer 3 until the work 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 to this, and other layers (die bonding film, etc.) may be laminated on the adhesive layer 3, and in The peeling sheet 6 is laminated on this other layer.

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

(4) Other components In the sheet 1 for workpiece processing of the present embodiment, an adhesive layer may be stacked on the surface of the adhesive layer 3 opposite to the base material 2 (hereinafter referred to as "adhesive surface"). In this case, the sheet 1 for workpiece processing of the present embodiment can be used as a dicing die bonding sheet by having the above-mentioned adhesive layer. In this cutting, the die bonding sheet 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 with a laminated adhesive layer . This wafer can be easily fixed to the object on which the wafer is mounted by singulation of the adhesive layer. As a material constituting the adhesive layer, those containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, or those containing a B-stage (semi-cured) thermosetting adhesive component, or the like are preferably used.

In addition, in the sheet 1 for workpiece processing of the present embodiment, a protective film may be formed on the adhesive area of the adhesive layer 3. In this case, the sheet 1 for workpiece processing of this embodiment can be used as a sheet for forming and cutting a protective film. In such a sheet for forming and cutting a protective film, a work piece is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the work piece and the protective film forming layer are cut at the same time, whereby a laminated protective film can be obtained Layered wafers. As the object to be cut, it is preferable to use a circuit formed on one surface. In this case, a protective film forming layer is usually formed on an area opposite to the surface on which the circuit is formed. The monolithic protective film forming layer is hardened at a set time point (preferably before the dicing step), whereby a protective film with 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 situation, the object of laser marking is not the workpiece itself, but the adhesive layer or protective film. However, even in these cases, the effects of excellent laser marking property and laser light resistance described above can also be obtained.

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

In the adhesive layer 3 of this embodiment, a mold that can attach a lead frame or the like is preferable. 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. With this, the adhesion force to the mold of the lead frame or the like can be maintained to a high level.

The laminate of the base material 2 and the adhesive layer 3 may be half-cut according to requirements to form a desired shape, for example, a shape corresponding to the circular shape of the workpiece (semiconductor wafer). In this case, the residual portion produced by half-cutting can be appropriately removed.

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

A method of manufacturing a wafer from a semiconductor wafer that is a workpiece by blade cutting or stealth cutting using the sheet 1 for processing a workpiece of the present embodiment will be described below as an example.

First, the sheet 1 for workpiece processing wound into a roll shape is successively released while peeling off the peeling sheet 6, and as shown in FIG. 2, the semiconductor wafer 7 is attached to the adhesive layer 3 of the sheet 1 for workpiece processing And wire frame 8. Thereby, a laminated structure having the structure of the area layer semiconductor wafer 7 and the lead frame 8 on the side of the adhesive layer 3 of the workpiece processing sheet 1 is obtained (hereinafter, referred to as a “laminated structure L”).

Then, the laminated structure L is subjected to a laser marking step. Specifically, using a laser irradiation device for laser marking, the semiconductor wafer 7 is irradiated with laser light through the work 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 sheet 1 for workpiece processing of the present embodiment, since the physical properties of the base material 2 are set as described above, the laser light is easily transmitted. Therefore, the laser-engraved printing 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, the base material 2 can be suppressed from scorching. Therefore, there is no decrease in the light transmittance caused by the scorching of the base material 2, and the printing formed on the workpiece can be well recognized by the sheet 1 for workpiece processing.

Then, the laminated structure L is subjected to a cutting step. In the case of blade dicing, a dicing blade is used to cut the semiconductor wafer 7 and divide it, thereby obtaining a wafer. After that, an extension step for extending the workpiece processing sheet 1 is performed so as to be easily picked up in the subsequent pickup step, and the interval between the wafers is enlarged.

On the other hand, in the case of invisible dicing, a laser irradiation device (laser dicing machine) for division processing is used to irradiate the semiconductor wafer 7 with the laser light through the work processing sheet 1 to form a reformation in the semiconductor wafer 7. Quality layer. In addition, since the physical properties of the base material 2 are set as described above, the laser light transmission of the laser cutter is also excellent. After that, by performing a stretching step to extend the sheet 1 for workpiece processing, a force (pulling force in the main surface direction) is applied to the semiconductor wafer 7. As a result, the semiconductor wafer 7 adhered to the sheet 1 for workpiece processing is divided to obtain a wafer.

Then, using a pickup device, the wafer is picked up from the workpiece processing sheet 1. Here, in the case where 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 line. Thereby, the adhesive force of the adhesive layer 3 can be reduced, and the wafer can be easily picked up. The above-mentioned active energy rays generally use ultraviolet rays, electron rays, etc., and particularly preferably ultraviolet rays that are easily available.

The irradiation of the above-mentioned ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion lamp, a xenon lamp, an LED, etc. The irradiation amount of the ultraviolet rays is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. The amount of ultraviolet light is preferably 50 mJ/cm ² or more, particularly 80 mJ/cm ² or more, and more preferably 100 mJ/cm ² or more. In addition, the amount of ultraviolet light is preferably 2000 mJ/cm ² or less, particularly preferably 1000 mJ/cm ² or less, and further preferably 500 mJ/cm ² or less.

As described above, since the scorching of the substrate 2 caused by laser marking is suppressed, even if the adhesive layer 3 is irradiated with ultraviolet rays through the substrate 2 as described above, the adhesive layer 3 can be cured well. Therefore, the problem that residual paste residue of the adhesive adheres to the wafer after pickup is less likely to occur.

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

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

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

(2) Preparation of coating agent for adhesive layer 72 parts by mass of butyl acrylate and 28 parts by mass of 2-hydroxyethyl acrylate (HEA) were copolymerized, and the resulting copolymer and methacryl oxyethyl isocyanate (MOI) were compared with the copolymer. 80 mol% of HEA was reacted to obtain an active energy ray-curable acrylic polymer (weight average molecular weight of 500,000) having an active energy ray polymerizable group in the side chain.

To 100 parts by mass of the active energy ray-curable acrylic polymer (solid content concentration; the same below), 3.0 parts by mass of a photopolymerization initiator (manufactured by BASF, product name "Irgacure184") and an isocyanate compound (Tosoh Corporation) Manufactured, product name "Coronate L") 1.0 parts by mass, and diluted with a solvent, thereby obtaining a coating agent for an adhesive layer.

(3) Manufacture of sheets for workpiece processing Prepare a peeling sheet (product name "SP-PET 381031" manufactured by Lintech Corporation) with a silicone-based peeling agent layer on one side of a 38 μm thick polyethylene terephthalate film. Here, the peeling surface of the peeling sheet The coating agent for the adhesive layer described above 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 substrate prepared above was aligned and bonded together to obtain a laminate composed of a substrate (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 having a diameter of 370 mm.

[Example 2] The polyvinyl chloride resin composition was extruded by a small T-shaped die extruder (manufactured by Toyo Seiki 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 mean roughness (Ra) and maximum height roughness (Rz)) of the back surface of the obtained base material was measured by the method mentioned later, and it is shown in Table 1.

The sheet for workpiece processing was produced in the same manner as in Example 1, except that the above-mentioned substrate was used.

[Example 3] The resin composition of the ethylene-(meth)acrylic copolymer is extruded by a small T-shaped die extruder (manufactured by Toyo Seiki Co., Ltd., product name "LABO PLASTOMILL") to produce a base composed of a resin film with a thickness of 80 μm material. 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 mentioned later, and it is shown in Table 1.

The sheet for workpiece processing was produced in the same manner as in Example 1, except that the above-mentioned substrate was used.

[Comparative Example 1] The resin composition of the ethylene-(meth)acrylic copolymer is extruded by a small T-shaped die extruder (manufactured by Toyo Seiki Co., Ltd., product name "LABO PLASTOMILL") to produce a base composed of a resin film with a thickness of 80 μm material. 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 mentioned later, and it is shown in Table 1.

The sheet for workpiece processing was produced in the same manner as in Example 1, except that the above-mentioned substrate was used.

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

The sheet for workpiece processing was produced in the same manner as in Example 1, except that the above-mentioned substrate was used.

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

The sheet for workpiece processing was produced in the same manner as in Example 1, except that the above-mentioned substrate was used.

[Test Example 1] >Measurement of surface roughness of substrate> For the arithmetic average roughness (Ra; unit μm) and maximum height roughness (Rz; unit μm) of the back surface of the substrates prepared in Examples and Comparative Examples, a contact surface roughness meter (manufactured by Mitutoyo Corporation, product name) was used "SV3000S4"), measured according to JIS B0601: 1999 under the following measurement conditions. The results are shown in Table 1. [Measurement conditions] Evaluation length: 10 mm Reference length: 2.5 mm Scanning speed: 1.0 mm/sec Cutoff value: 0.25 mm

[Test Example 2] >Measurement of light transmittance> For the substrates prepared in the examples and comparative examples, an ultraviolet-visible-near infrared spectrophotometer (manufactured by Shimadzu Corporation, product name "UV-3600") was used, and the light transmittance was measured by the direct light receiving method, and the wavelength was 400 nm. , 532 nm and 800 nm transmittance. The results are shown in Table 1.

[Test Example 3] >Evaluation of laser marking property> Using a tape mounter device (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 Polished surface of silicon wafer (diameter: 12 inches, thickness: 350 μm) after #2000 grinding. At the same time, the exposed adhesive layer is attached to the lead frame.

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

After that, the workpiece processing sheet was peeled from the silicon wafer, and the printing formed on the silicon wafer was confirmed using a digital microscope (manufactured by KEYENCE, product name "DigitalMicroscope VHX-1000, magnification: 100 times"). As a result, the printing was not rough and the precision was high, and was evaluated as ◎, the printing was a little rough, but the precision was somewhat high, and the former was rated as ○, and the printing was rough and low in precision. Former evaluation is ╳. The results are shown in Table 1.

[Test Example 4] >Evaluation of laser light tolerance> In the same way as in Test Example 3, the silicon wafer was irradiated with laser light with a wavelength of 532 nm through the workpiece processing sheet, and printing was performed on the silicon wafer. After that, the sheet for workpiece processing is peeled from the silicon wafer, and it is visually confirmed whether the substrate of the sheet for workpiece processing is burnt (printed) due to laser light. As a result, those with no scorching (printing) on the substrate were evaluated as ○, and those with scorching (printing) on the substrate were evaluated as ╳. The results are shown in Table 1.

[Table 1]

As can be seen from Table 1, the sheet for workpiece processing obtained in Examples is excellent in laser marking property and resistant to laser light. [Industry availability]

The sheet for workpiece processing of the present invention is suitable for applications that include a workpiece for semiconductor wafers, glass plates, etc., and the step of performing laser marking through the sheet for workpiece processing.

1‧‧‧Working sheet 2‧‧‧ Base material 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 cross-sectional view showing a use example of a workpiece processing sheet according to an embodiment of the present invention, specifically showing a laminated structure.

1‧‧‧Working sheet

2‧‧‧ Base material

3‧‧‧Adhesive layer

6‧‧‧ peeling sheet

Claims (6)

A sheet for workpiece processing, which is a sheet for workpiece processing having at least a base material and an adhesive layer stacked 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, 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. The sheet for workpiece processing as described in item 1 of the patent application scope, in which the light transmittance of the substrate at a wavelength of 400 nm is more than 40%. The sheet for workpiece processing as described in item 1 of the patent application scope, in which the light transmittance of the substrate at a wavelength of 800 nm is more than 45%. The sheet for workpiece processing as described in item 1 of the scope of the patent application is used for the purpose of including the step of laser marking the workpiece through the sheet for workpiece processing. The sheet for workpiece processing as described in any one of items 1 to 4 of the patent application scope is used for cutting. The sheet for workpiece processing as described in item 5 of the patent application scope is used for invisible cutting.

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