JP7688508B2 - Workpiece processing sheet, dicing die bonding sheet, composite sheet for forming back surface protective film, and method for manufacturing workpiece - Google Patents

Description

The present invention relates to a workpiece processing sheet, a dicing die bonding sheet comprising the workpiece processing sheet, a composite sheet for forming a back surface protective film comprising the workpiece processing sheet, and a method for manufacturing a workpiece.

A dicing sheet used as a workpiece processing sheet is constructed with an adhesive layer on a base film, and is attached to a workpiece such as a semiconductor wafer using the adhesive layer, and is used in this state for dicing. After dicing, if necessary, the adhesive strength of the adhesive layer is reduced by curing it through exposure to energy rays such as ultraviolet light, and the processed workpiece such as a semiconductor chip is picked up. Dicing sheets with various configurations have been proposed so far depending on the purpose.

In the dicing process of workpieces such as semiconductor wafers, a dicing die bonding sheet is sometimes used, which is a combination of a film adhesive for bonding semiconductor elements to lead frames or organic substrates and a dicing sheet. In addition, a composite sheet for forming a back surface protective film, which is a combination of a protective film forming film and a dicing sheet, is also used to protect the back surface of the workpiece of a semiconductor device that uses a mounting method known as the face down method.

On the other hand, in recent years, semiconductor chips (semiconductor wafers) have become thinner as electronic devices become more multifunctional and highly integrated. There is also a demand for providing inexpensive semiconductor chips by dicing using a blade dicer, which is an inexpensive general-purpose product. When such thin semiconductor wafers are used, chipping, which occurs when dicing, is likely to occur on the outer edge of the chip (see, for example, Patent Documents 1 and 2).

JP 2008-103655 A JP 2009-035717 A

For example, Patent Documents 1 and 2 also explain that when a semiconductor wafer is blade diced using a dicing sheet, chips (i.e., chipping) occur on the dicing lines of the cut chips. Patent Document 1 explains that chipping of 30 to 150 μm in size occurs, while Patent Document 2 explains that chipping of 15 μm or more, or 10 μm or more in size does not occur.
However, after starting dicing with a new blade, the size of chipping tends to gradually increase as the number of blade dicing operations increases. If the size of chipping is large, it may cause failure of the semiconductor device itself.

The present invention aims to provide a workpiece processing sheet that can suppress an increase in chipping size even when blade dicing is repeated in the dicing process of a workpiece such as a semiconductor wafer, a dicing die bonding sheet that includes the workpiece processing sheet, a composite sheet for forming a back surface protective film that includes the workpiece processing sheet, and a method for manufacturing a workpiece.

In order to solve the above problems, the inventors conducted extensive research and discovered that by incorporating a metal soap into the adhesive layer, an increase in chipping size can be suppressed even if the number of workpieces, such as semiconductor wafers, to be blade diced is increased after starting dicing with a new blade, and thus the present invention was completed.

The present invention has the following aspects.
[1] A pressure-sensitive adhesive sheet comprising a base film and a pressure-sensitive adhesive layer provided on the base film,
The pressure-sensitive adhesive layer contains a metal soap,
A workpiece processing sheet, wherein the metal content per area of the adhesive layer is 0.0004 μg/ ^cm2 or more.
[2] The workpiece processing sheet according to [1], wherein the metal soap is a fatty acid zirconium salt, a fatty acid zinc salt, a fatty acid aluminum salt or a fatty acid nickel salt.
[3] The workpiece processing sheet according to [1] or [2], wherein the carbon number of the fatty acid of the fatty acid metal salt as the metal soap is 5 to 20.
[4] The workpiece processing sheet according to any one of [1] to [3],
A dicing die bonding sheet comprising a film-like adhesive on a first surface of the pressure-sensitive adhesive layer opposite the base film.
[5] The workpiece processing sheet according to any one of [1] to [3],
The composite sheet for forming a back surface protective film comprises a film for forming a protective film on a first surface of the pressure-sensitive adhesive layer opposite to the base film.
[6] A step of attaching the workpiece processing sheet according to any one of [1] to [3] to the back surface of a workpiece;
and a dicing step of blade dicing the work to obtain a work piece.

According to the present invention, there are provided a workpiece processing sheet that can suppress an increase in chipping size even when blade dicing is repeated in a dicing process for a workpiece such as a semiconductor wafer, a dicing die bonding sheet that includes the workpiece processing sheet, a composite sheet for forming a back surface protective film that includes the workpiece processing sheet, and a method for manufacturing a workpiece.

1 is a cross-sectional view showing a schematic diagram of one embodiment of a workpiece processing sheet of the present invention. FIG. 2 is a cross-sectional view showing a schematic diagram of another embodiment of the workpiece processing sheet of the present invention. 1 is a cross-sectional view showing a schematic diagram of one embodiment of a dicing-die bonding sheet of the present invention. 1 is a cross-sectional view showing a schematic diagram of one embodiment of a composite sheet for forming a back surface protective film of the present invention. 1 is a cross-sectional view showing a schematic diagram of one embodiment of a method for manufacturing a workpiece according to the present invention;

<<Work processing sheets>>

The workpiece processing sheet of the present invention will be described with reference to the drawings. Note that the drawings used in the following description may show the main parts enlarged for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

FIG. 1 is a cross-sectional view showing a schematic diagram of one embodiment of the workpiece processing sheet of the present invention.
The workpiece processing sheet 101 shown here is a dicing sheet having an adhesive layer 12 on a base film 11, and the adhesive layer 12 contains metal soap.

In the workpiece processing sheet 101, an adhesive layer 12 is laminated on one surface 11a (hereinafter sometimes referred to as the "first surface") of the base film 11.

The workpiece processing sheet 101 shown in FIG. 1 is used by attaching the first surface 12a of the adhesive layer 12 opposite the base film 11 to the surface of a workpiece (not shown) such as a semiconductor wafer, opposite the surface on which the circuit is formed.

Here, the term "workpiece" refers to a wafer or a semiconductor device panel.
Examples of the "wafer" include semiconductor wafers made of elemental semiconductors such as silicon, germanium, and selenium, and compound semiconductors such as GaAs, GaP, InP, CdTe, ZnSe, and SiC; and insulator wafers made of insulators such as sapphire and glass.
The term "semiconductor device panel" refers to an assembly of two or more semiconductor devices, each having one or more electronic components sealed with a sealing resin layer, arranged side by side in a plane.
A circuit is formed on one surface of each of these workpieces, and in this specification, the surface of the workpiece on which the circuit is formed is referred to as the "circuit surface," and the surface of the workpiece opposite to the circuit surface is referred to as the "rear surface."
The work is divided by means of dicing or the like to become workpieces. In this specification, as in the case of the work, the surface of the workpiece on which a circuit is formed is referred to as the "circuit side," and the surface of the workpiece opposite to the circuit side is referred to as the "rear side."
Both the circuit surface of the workpiece and the circuit surface of the workpiece are provided with protruding electrodes such as bumps, pillars, etc. The protruding electrodes are preferably made of solder.

In the workpiece processing sheet 101, the metal content per area of the adhesive layer 12 is 0.0004 μg/cm ² or more. The metal content per area (μg/cm ² ) of the adhesive layer 12 is calculated by the following formula.
Metal content per area of adhesive layer 12 (μg/cm ² )
= Metal content of adhesive layer 12 (μg) / Area of first surface of adhesive layer 12 (cm ² )

In the process of dicing a workpiece using the workpiece processing sheet 101, since the adhesive layer 12 contains metal soap, even if the number of workpieces to be blade diced is increased after starting dicing using a new blade, an increase in chipping size can be suppressed.
It is believed that the metal soap contained in the adhesive layer prevents the adhesive from adhering to the blade, and the blade surface is kept clean, resulting in a clean cut surface, and chipping is suppressed even when the number of diced sheets increases through repeated blade dicing of the workpiece. Also, the metal content per area of the adhesive layer 12 affects the effect of suppressing chipping.

When the workpiece processing sheet 101 is viewed in plan from above the adhesive layer 12 side, the adhesive layer 12 has a shape such as a circle.

The workpiece processing sheet of the present invention is not limited to the workpiece processing sheet 101 shown in FIG. 1, and some of the configuration shown in FIG. 1 may be changed, deleted, or added within the scope that does not impair the effects of the present invention.

For example, the adhesive layer 12 may be one layer (single layer) or two or more layers. FIG. 2 is a cross-sectional view showing a schematic diagram of another embodiment of the work processing sheet of the present invention. The work processing sheet 101' shown here is a dicing sheet having an adhesive layer 12 on a base film 11. In FIG. 2 and subsequent figures, components that are the same as those shown in the figures already described are given the same reference numerals as in the figures already described, and detailed descriptions thereof are omitted.

In the workpiece processing sheet 101', an adhesive layer 12 is laminated on one surface (hereinafter sometimes referred to as the "first surface") 11a of the base film 11, and the adhesive layer 12 is composed of a first adhesive layer 121 on the side opposite the base film 11 and a second adhesive layer 122 on the base film 11 side, and the first adhesive layer 121 contains a metal soap.

The workpiece processing sheet 101' shown in FIG. 2 is used by attaching the first surface 12a of the adhesive layer 12 opposite the base film 11 to the back surface of a workpiece (not shown) such as a semiconductor wafer, opposite the circuit surface.

Below, we will explain each layer that makes up the dicing sheet as the workpiece processing sheet of the present invention.

[Base film]
The material of the base film is preferably various resins, and specifically, for example, polyethylene (sometimes abbreviated as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE, etc.)), polypropylene, polybutene, polybutadiene, polymethylpentene, styrene-ethylenebutylene-styrene block copolymer, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate (sometimes abbreviated as PET), polybutylene terephthalate, polyurethane, polyurethane acrylate, polyimide, ethylene vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, polystyrene, polycarbonate, fluororesin, water additive, modified product, crosslinked product or copolymer of any of these resins, etc. are mentioned. From the viewpoint of cutting chip suppression and expandability, low density polyethylene (LDPE) film, ethylene-methacrylic acid (EMAA) copolymer film, ethylene-(meth)acrylate (EMMA) copolymer film are preferable.

In this specification, "(meth)acrylic acid" is a concept that includes both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid. For example, "(meth)acrylate" is a concept that includes both "acrylate" and "methacrylate," and "(meth)acryloyl group" is a concept that includes both "acryloyl group" and "methacryloyl group."

The resin constituting the base film may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be selected arbitrarily.

The base film may be made of one layer (i.e., a single layer) or may be made of two or more layers. When the base film is made of multiple layers, these layers may be the same or different from each other. That is, all layers may be the same, all layers may be different, or only some layers may be the same. When the layers are different from each other, the combination of these layers is not particularly limited as long as it does not impair the effect of the present invention. Here, the layers being different from each other means that at least one of the material and thickness of each layer is different from each other.
In this specification, not only in the case of a base film, "multiple layers may be the same or different" means "all layers may be the same, all layers may be different, or only some layers may be the same", and further, "multiple layers are different" means "at least one of the constituent materials and thicknesses of each layer is different from each other".

The thickness of the substrate film can be appropriately selected depending on the purpose, but is preferably from 20 μm to 200 μm, more preferably from 25 μm to 150 μm, and particularly preferably from 30 μm to 100 μm.
Here, the "thickness of the base film" means the thickness of the entire base film, and for example, the thickness of a base film consisting of multiple layers means the total thickness of all layers constituting the base film. Note that, as a method for measuring the thickness of the base film, for example, a method of measuring the thickness at any five points using a contact thickness meter and calculating the average of the measured values can be mentioned.

In order to improve adhesion to other layers, such as a pressure-sensitive adhesive layer, provided thereon, the substrate film may be subjected to a surface treatment such as sandblasting, solvent treatment, embossing, or an oxidation treatment such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone/ultraviolet radiation treatment, flame treatment, chromic acid treatment, or hot air treatment.
The surface of the base film may be treated with a primer.
The base film may also have an antistatic coating layer, a layer that prevents the base film from adhering to other sheets or to an adsorption table when the film-like adhesive composite sheet is stacked and stored, and the like.
Of these, it is preferable for the substrate film to have its surface subjected to electron beam irradiation treatment in order to prevent the generation of fragments of the substrate film due to friction of the blade when dicing the workpiece, whereas it is preferable for the substrate film not to have been subjected to electron beam irradiation treatment in order to facilitate pick-up.

[Adhesive layer]
The pressure-sensitive adhesive layer contains a metal soap, and the metal content per area of the pressure-sensitive adhesive layer is 0.0004 μg/cm ² or more.

The pressure-sensitive adhesive layer contains metal as metal soap. In the dicing process of the workpiece, even if the number of workpieces to be diced with the blade is increased after starting dicing with a new blade, the increase in chipping size can be suppressed, so that the metal content per area of the pressure-sensitive adhesive layer is 0.0004 μg/ ^cm2 or more, preferably 0.001 μg/ ^cm2 or more, more preferably 0.003 μg/ ^cm2 or more, and particularly preferably 0.005 μg/ ^cm2 or more.

The metal content per area of the pressure-sensitive adhesive layer is preferably 100,000 μg/ ^cm2 or less, more preferably 1,000 μg/ ^cm2 or less, even more preferably 100 μg/ ^cm2 or less, still more preferably 10 μg/ ^cm2 or less, and may be 1 μg/ ^cm2 or less, 0.5 μg/ ^cm2 or less, or may be 0.2 μg/ ^cm2 or less. By having the metal content per area be equal to or less than the upper limit, corrosion of a device in contact with the pressure-sensitive adhesive layer can be prevented.

The thickness of the pressure-sensitive adhesive layer can be appropriately selected depending on the purpose, but is preferably 1 to 100 μm, more preferably 1 to 60 μm, and particularly preferably 1 to 30 μm.
Here, the "thickness of the adhesive layer" means the thickness of the entire adhesive layer, and for example, the thickness of an adhesive layer consisting of multiple layers means the total thickness of all layers constituting the adhesive layer. The thickness of the adhesive layer can be measured, for example, by measuring the thickness at any five points using a contact thickness meter and calculating the average of the measured values.

The cutting depth of the blade into the dicing sheet by the blade dicing of the workpiece is often set to 0 to 30 μm from the first surface 12a of the adhesive layer 12. When the thickness of the adhesive layer is less than 20 μm, the metal content per area of the adhesive layer is 0.0004 μg/cm ² or more, preferably 0.001 μg/cm ² or more, more preferably 0.003 μg/cm ² or more, and particularly preferably 0.005 μg/cm ² or more. When the thickness of the adhesive layer is 20 μm or more, the metal content per area up to 20 μm in the vicinity of the first surface of the adhesive layer is preferably 0.0004 μg/cm ² or more, more preferably 0.001 μg/cm ² or more, even more preferably 0.003 μg/cm ² or more, and particularly preferably 0.005 μg/cm ² or more. For example, when the adhesive layer is composed of a first adhesive layer on the side opposite to the base film 11 and a second adhesive layer on the side of the base film 11, the thickness of the first adhesive layer is less than 20 μm, and the metal content per area of the first adhesive layer is preferably 0.0004 μg/ ^cm2 or more, more preferably 0.001 μg/ ^cm2 or more, even more preferably 0.003 μg/ ^cm2 or more, and particularly preferably 0.005 μg/ ^cm2 or more.

The metal content per area of the first pressure-sensitive adhesive layer is preferably 100,000 μg/ ^cm2 or less, more preferably 1,000 μg/cm2 or less, even more preferably 100 μg/ ^cm2 or ^less , and still more preferably 10 μg/cm2 or ^less , and may be 1 μg/ ^cm2 or less, 0.5 μg/ ^cm2 or less, or may be 0.2 μg/cm2 or ^less . By having the metal content per area be equal to or less than the upper limit, corrosion of a device in contact with the pressure-sensitive adhesive layer can be prevented.

The adhesive layer can be formed using an adhesive composition containing various components for constituting the adhesive layer. The ratio of the contents of the components in the adhesive composition that do not vaporize at room temperature is usually the same as the ratio of the contents of the components in the adhesive layer. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples of such temperatures include temperatures of 15 to 30°C.

When the adhesive layer contains an energy ray curable component, the adhesive layer can be irradiated with energy rays to reduce its adhesiveness, making it easier to pick up the workpiece. The process of irradiating the adhesive layer with energy rays to reduce its adhesiveness may be performed after the workpiece processing sheet is attached to the adherend, or may be performed in advance before attaching the workpiece processing sheet to the adherend.

In the present invention, the term "energy ray" refers to electromagnetic waves or charged particle beams that have an energy quantum, and examples of such beams include ultraviolet rays and electron beams.
The ultraviolet light can be irradiated by using, for example, a UV-LED, a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, etc. as an ultraviolet light source. The electron beam can be generated by an electron beam accelerator or the like.
In the present invention, "energy ray curable" means a property of being cured by irradiation with energy rays, and "non-energy ray curable" means a property of not being cured even when irradiated with energy rays.

Preferred examples of the pressure-sensitive adhesive composition include those containing an acrylic polymer and an energy ray-polymerizable compound (hereinafter sometimes abbreviated as "pressure-sensitive adhesive composition (i)"), and those containing an acrylic polymer having a hydroxyl group and a polymerizable group on the side chain (for example, having a hydroxyl group and a polymerizable group on the side chain via a urethane bond) and an isocyanate-based crosslinking agent (hereinafter sometimes abbreviated as "pressure-sensitive adhesive composition (ii)"). Those that further contain a solvent are preferred.

[Adhesive composition (i)]
The pressure-sensitive adhesive composition (i) is a raw material for producing the pressure-sensitive adhesive layer, and contains the acrylic polymer and the energy ray-polymerizable compound as essential components.
Each component will be described below.

(Acrylic polymer)
A preferred example of the acrylic polymer in the pressure-sensitive adhesive composition (i) is a (meth)acrylic acid ester copolymer obtained by polymerizing a (meth)acrylic acid ester as a monomer and a non-(meth)acrylic acid ester that is used as needed.
Examples of the (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and the like. (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), isooctadecyl cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate; cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate; imide (meth)acrylates; glycidyl group-containing (meth)acrylates such as glycidyl (meth)acrylate; and hydroxyl group-containing (meth)acrylates such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

The non-(meth)acrylic acid ester is a monomer other than a (meth)acrylic acid ester, and preferred examples include (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

The monomers constituting the acrylic polymer, such as the (meth)acrylic acid ester and the non-(meth)acrylic acid ester, may be one type or two or more types.

The pressure-sensitive adhesive composition (i) may contain only one type of acrylic polymer, or two or more types.

The content of the acrylic polymer in the adhesive composition (i) is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total amount of all components other than the solvent in the adhesive composition (i). The content of the acrylic polymer in the adhesive composition (i) is preferably 99% by mass or less, more preferably 91% by mass or less, based on the total amount of all components other than the solvent in the adhesive composition (i).

(Energy Ray Polymerizable Compound)
The energy ray-polymerizable compound is a compound that is polymerized and cured by irradiation with energy rays such as ultraviolet rays and electron beams, and has an energy ray-curable double bond in the molecule.
Examples of the energy ray-polymerizable compound include low molecular weight compounds (monofunctional or polyfunctional monomers and oligomers) having an energy ray-polymerizable group. More specific examples include acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, and 1,6-hexanediol diacrylate; cyclic aliphatic skeleton-containing acrylates such as dicyclopentadiene dimethoxy diacrylate; and acrylate-based compounds such as polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy modified acrylate, polyether acrylate, and itaconic acid oligomer.
The energy ray polymerizable compound preferably has a molecular weight of 100 to 30,000, and more preferably 300 to 10,000.

The pressure-sensitive adhesive composition (i) may contain only one type of energy ray-polymerizable compound, or two or more types.

The content of the energy ray polymerizable compound in the pressure-sensitive adhesive composition (i) is preferably 1 to 125 parts by mass, and more preferably 10 to 125 parts by mass, per 100 parts by mass of the acrylic polymer.

(Photopolymerization initiator)
The pressure-sensitive adhesive composition (i) may contain a photopolymerization initiator in addition to the acrylic polymer and the energy ray-polymerizable compound.
The photopolymerization initiator may be a known one, and specifically, examples of the photopolymerization initiator include α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; and ketal compounds such as benzyl dimethyl ketal. aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; and acylphosphonates.

The pressure-sensitive adhesive composition (i) may contain only one type of photopolymerization initiator, or two or more types.

When a photopolymerization initiator is used, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition (i) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the energy ray-polymerizable compound. When the content of the photopolymerization initiator is equal to or greater than the lower limit, the effect of using the photopolymerization initiator can be sufficiently obtained. Furthermore, when the content of the photopolymerization initiator is equal to or less than the upper limit, the generation of by-products from excess photopolymerization initiator is suppressed, and the curing of the pressure-sensitive adhesive layer proceeds more smoothly.

(Crosslinking Agent)
The pressure-sensitive adhesive composition (i) may contain a crosslinking agent in addition to the acrylic polymer and the energy ray-polymerizable compound.
Examples of the crosslinking agent include an organic polyvalent isocyanate compound and an organic polyvalent imine compound.

Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and trimers, isocyanurates, and adducts of these compounds, as well as terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with polyol compounds. The adducts refer to the reaction products of the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil.

Specific examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; a compound in which either or both of tolylene diisocyanate and hexamethylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, etc.

Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinyl propionate, tetramethylolmethane-tri-β-aziridinyl propionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine, etc.

When an isocyanate compound is used as the crosslinking agent, it is preferable to use a hydroxyl group-containing polymer as the acrylic polymer. When the crosslinking agent has an isocyanate group and the acrylic polymer has a hydroxyl group, a crosslinked structure can be easily introduced into the adhesive layer by the reaction between the isocyanate group and the hydroxyl group.

The pressure-sensitive adhesive composition (i) may contain only one type of crosslinking agent, or two or more types.

When a crosslinking agent is used, the content of the crosslinking agent in the pressure-sensitive adhesive composition (i) is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 16 parts by mass, per 100 parts by mass of the acrylic polymer.

(Metal soap)
The metal soap contained in the pressure-sensitive adhesive composition (i) can be appropriately selected from known metal soaps. The metal soap refers to a fatty acid metal salt in which a fatty acid such as myristic acid, palmitic acid, stearic acid, oleic acid, lauric acid, ricinoleic acid, or octylic acid is combined with a metal such as zirconium, aluminum, nickel, calcium, magnesium, cobalt, manganese, bismuth, potassium, neodymium, lead, zinc, copper, or iron.

Specific examples of the metal soap include metal stearates such as zirconium stearate, zinc stearate, aluminum stearate, nickel stearate, lead stearate, bismuth stearate, cobalt stearate, manganese stearate, potassium stearate, neodymium stearate, lithium stearate, magnesium stearate, calcium stearate, and barium stearate; metal laurates such as zirconium laurate, zinc laurate, aluminum laurate, nickel laurate, calcium laurate, and barium laurate; metal ricinoleates such as zirconium ricinoleate, zinc ricinoleate, aluminum ricinoleate, nickel ricinoleate, calcium ricinoleate, and barium ricinoleate; metal octylates such as zirconium octylate, zinc octylate, aluminum octylate, and nickel octylate; and fatty acid zirconium salts bonded to fatty acids such as zirconium 2-ethylhexanoate and zirconium oxide (2-ethylhexanoate).
The metal soap may be one or more of the above metal soaps. Metal soaps commercially available under the trade name "DICNATE (registered trademark)" (manufactured by DIC Corporation) may be used.

Among the metal soaps, fatty acid zirconium salts, fatty acid zinc salts, fatty acid aluminum salts, and fatty acid nickel salts are preferred, and fatty acid zirconium salts and fatty acid zinc salts are more preferred.

The number of carbon atoms in the fatty acid of the fatty acid metal salt as the metal soap is preferably 5 to 20, more preferably 6 to 18, and particularly preferably 7 to 16.

When the metal soap is present in the adhesive layer (i) in the form of a filler, it is more preferable that the average particle size of the filler-like metal soap is 50 nm or less, or that the metal soap is dissolved in the adhesive layer (i), in order to prevent wear and chipping of the blade. It is preferable that the metal soap is uniformly dispersed in the adhesive layer (i). When the adhesive layer (i) is composed of a first adhesive layer on the side opposite to the base film 11 and a second adhesive layer on the side of the base film 11, it is preferable that the metal soap is uniformly dispersed in the first adhesive layer.

(solvent)
The pressure-sensitive adhesive composition (i) preferably further contains a solvent in addition to the acrylic polymer and the energy ray-polymerizable compound.
The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.
The pressure-sensitive adhesive composition (i) may contain only one type of solvent, or two or more types of solvents.

When the adhesive composition (i) contains a solvent, the content of the solvent is preferably 40 to 90 mass %, and more preferably 50 to 80 mass %.

(Other ingredients)
The pressure-sensitive adhesive composition (i) may contain, in addition to the acrylic polymer and the energy ray-polymerizable compound, other components that do not fall under the category of a photopolymerization initiator, a crosslinking agent, and a solvent, within a range that does not impair the effects of the present invention.
The other components may be known ones and may be arbitrarily selected depending on the purpose, and are not particularly limited. Preferred examples of the other components include various additives such as dyes, pigments, antidegradants, antistatic agents, flame retardants, silicone compounds, and chain transfer agents.
The pressure-sensitive adhesive composition (i) may contain only one type of other component, or two or more types of other components.

[Adhesive composition (ii)]
The pressure-sensitive adhesive composition (ii) is also a raw material for producing the pressure-sensitive adhesive layer, and contains, as essential components, an acrylic polymer having a hydroxyl group and a polymerizable group on a side chain (for example, an acrylic polymer having a hydroxyl group and a polymerizable group on a side chain via a urethane bond) and an isocyanate-based crosslinking agent.
When the pressure-sensitive adhesive composition (ii) is used, the acrylic polymer has a polymerizable group on the side chain, and therefore the adhesive layer has reduced adhesion after the polymerization reaction (curing) and the peelability from the adherend is improved, and the pick-up ability of the workpiece is improved, compared to the case of the pressure-sensitive adhesive composition (i), in which an energy ray-polymerizable compound is used and polymerization reaction is carried out by irradiation with energy rays.
In this specification, the term "acrylic polymer" in the pressure-sensitive adhesive composition (ii) means "an acrylic polymer having a polymerizable group in the side chain", unless otherwise specified.

(Acrylic polymer)
An example of an acrylic polymer having the above-mentioned polymerizable group in a side chain can be one obtained by copolymerizing a (meth)acrylic acid ester as a monomer with a hydroxyl group-containing compound such as a hydroxyl group-containing (meth)acrylate, and reacting the hydroxyl group of the obtained hydroxyl group-containing copolymer with an isocyanate group of a compound having an isocyanate group and a polymerizable group to form a urethane bond.

Examples of the (meth)acrylic acid ester include the same (meth)acrylic acid esters as those in the pressure-sensitive adhesive composition (i) other than the hydroxyl group-containing (meth)acrylates.
Examples of the hydroxyl group-containing compound include the same compounds as the hydroxyl group-containing (meth)acrylates in the pressure-sensitive adhesive composition (i).
The (meth)acrylic acid ester and the hydroxyl group-containing compound constituting the acrylic polymer may be of one kind or of two or more kinds.

Examples of the compound having an isocyanate group and a polymerizable group include isocyanate group-containing (meth)acrylic acid esters such as 2-methacryloyloxyethyl isocyanate.
The compound having an isocyanate group and a polymerizable group that constitutes the acrylic polymer may be of only one type or of two or more types.

The pressure-sensitive adhesive composition (ii) may contain only one type of acrylic polymer, or two or more types.

The content of the acrylic polymer in the adhesive composition (ii) is preferably 80% by mass or more, more preferably 90% by mass or more, based on the total amount of all components other than the solvent in the adhesive composition (ii). The content of the acrylic polymer in the adhesive composition (ii) is preferably 99% by mass or less, more preferably 97% by mass or less, based on the total amount of all components other than the solvent in the adhesive composition (ii).

(Isocyanate-based crosslinking agent)
Examples of the isocyanate-based crosslinking agent include the same organic polyisocyanate compounds as the crosslinking agent in the pressure-sensitive adhesive composition (i).

The pressure-sensitive adhesive composition (ii) may contain only one type of isocyanate-based crosslinking agent, or two or more types.

The mole number of the isocyanate group of the isocyanate crosslinking agent in the adhesive composition (ii) is preferably 0.2 times or more the mole number of the hydroxyl group of the acrylic polymer in the adhesive composition (ii).By doing so, the peelability from the adherend is improved due to the decrease in the adhesiveness of the adhesive layer after curing, and the pick-up property of the workpiece is improved.
In addition, the number of moles of isocyanate groups in the isocyanate crosslinking agent in the pressure-sensitive adhesive composition (ii) is preferably 3 times or less the number of moles of hydroxyl groups in the acrylic polymer in the pressure-sensitive adhesive composition (ii). By doing so, the generation of by-products between the isocyanate crosslinking agents can be further suppressed.

The content of the isocyanate-based crosslinking agent in the pressure-sensitive adhesive composition (ii) may be adjusted as appropriate so that the number of moles of isocyanate groups falls within the range described above. With these conditions satisfied, the content is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.3 to 10 parts by mass, relative to 100 parts by mass of the acrylic polymer.

(Photopolymerization initiator)
The pressure-sensitive adhesive composition (ii) may contain a photopolymerization initiator in addition to the acrylic polymer and the isocyanate-based crosslinking agent.
Examples of the photopolymerization initiator include the same ones as those in the pressure-sensitive adhesive composition (i).
The pressure-sensitive adhesive composition (ii) may contain only one type of photopolymerization initiator, or may contain two or more types of photopolymerization initiators.

When a photopolymerization initiator is used, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition (ii) is preferably 0.05 to 20 parts by mass relative to 100 parts by mass of the acrylic polymer. When the content of the photopolymerization initiator is equal to or greater than the lower limit, the effect of using the photopolymerization initiator can be sufficiently obtained. Furthermore, when the content of the photopolymerization initiator is equal to or less than the upper limit, the generation of by-products from excess photopolymerization initiator is suppressed, and the curing of the pressure-sensitive adhesive layer proceeds more smoothly.

(Metal soap)
Examples of the metal soap contained in the pressure-sensitive adhesive composition (ii) include the same as those in the pressure-sensitive adhesive composition (i).

When the metal soap is present in the adhesive layer (ii) in the form of a filler, it is more preferable that the average particle size of the filler-like metal soap is 50 nm or less, or that the metal soap is dissolved in the adhesive layer, in order to prevent wear and chipping of the blade. It is preferable that the metal soap is uniformly dispersed in the adhesive layer (ii). When the adhesive layer (ii) is composed of a first adhesive layer on the side opposite to the base film 11 and a second adhesive layer on the side of the base film 11, it is preferable that the metal soap is uniformly dispersed in the first adhesive layer.

(solvent)
The pressure-sensitive adhesive composition (ii) preferably further contains a solvent in addition to the acrylic polymer and the isocyanate-based crosslinking agent.
Examples of the solvent include the same ones as those in the pressure-sensitive adhesive composition (i).
The pressure-sensitive adhesive composition (ii) may contain only one type of solvent, or two or more types of solvents.

When the adhesive composition (ii) contains a solvent, the content of the solvent is preferably 40 to 90 mass %, and more preferably 50 to 80 mass %.

(Other ingredients)
The pressure-sensitive adhesive composition (ii) may contain, in addition to the acrylic polymer and the isocyanate-based crosslinking agent, other components that do not fall under the category of a photopolymerization initiator and a solvent, within the range that does not impair the effects of the present invention.
Examples of the other components include the same as those in the pressure-sensitive adhesive composition (i).
The pressure-sensitive adhesive composition (ii) may contain only one type of other component, or two or more types of such other components.

The pressure-sensitive adhesive compositions such as the pressure-sensitive adhesive composition (i) and the pressure-sensitive adhesive composition (ii) can be obtained by blending an acrylic polymer with a component other than the acrylic polymer.
The order of addition of the components is not particularly limited, and two or more components may be added simultaneously.
The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blade, a method of mixing using a mixer, a method of mixing by applying ultrasound, etc.
The temperature and time during addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. The temperature is preferably 15 to 30°C.

The adhesive layer may be formed by adjusting, for example, the number of polymerizable groups such as (meth)acryloyl groups in each component such as the acrylic polymer blended in the adhesive composition, the type and amount of the crosslinking agent, the type of monomer constituting the acrylic polymer, etc., and, in the case of adhesive composition (i) only, the molecular weight of the energy ray-polymerizable compound and the ratio of the amount of the energy ray-polymerizable compound to the amount of the acrylic polymer, etc., so that the elastic modulus after curing by energy ray irradiation falls within a predetermined range.

The pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive composition to the surface of the base film and drying it.
At this time, if necessary, the applied pressure-sensitive adhesive composition may be heated for crosslinking. The heating conditions may be, for example, but are not limited to, 100 to 130° C. for 1 to 5 minutes.
Alternatively, the adhesive layer can be formed on the base film by applying the adhesive composition to the release-treated surface of a release film, drying the adhesive composition to form an adhesive layer, bonding the resulting adhesive layer to the surface of the base film, and removing the release film as necessary.

The adhesive composition may be applied to the surface of the substrate film or the release layer surface of the release material by a known method, such as a method using various coaters, such as an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Mayer bar coater, or kiss coater.

<Release film>
The release film is not particularly limited, and commercially available release films can be used, such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Crosslinked films of these films can also be used. Furthermore, laminated films of these films can also be used.

The surface tension of the release film on the surface in contact with the adhesive layer is preferably 40 mN/m or less, more preferably 37 mN/m or less, and particularly preferably 35 mN/m or less. The lower limit is usually about 25 mN/m. A release film with such a relatively low surface tension can be obtained by appropriately selecting the material, or by applying a release agent to the surface of the release film and carrying out a release treatment.

Releasers used in the peeling process include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, wax-based, and rubber-based release agents, but alkyd-based, silicone-based, and fluorine-based release agents are particularly preferred because they are heat resistant.

To use the above release agents to perform a release treatment on the surface of a film or other material that will serve as the base of the release film, the release agent can be applied directly without solvent, or diluted with a solvent or made into an emulsion, using a gravure coater, Mayer bar coater, air knife coater, roll coater, or the like, and the release film to which the release agent has been applied can be left at room temperature or under heat, or cured with an electron beam to form a release agent layer.

The surface roughness (Ra) of the release film is preferably 10 to 100 nm, more preferably 15 to 60 nm, and even more preferably 20 to 50 nm.

<<Method of manufacturing workpiece processing sheet>>
The workpiece processing sheet can be manufactured by laminating the above-mentioned layers in order so that they are in the corresponding positional relationship. The method of forming each layer is as described above.

For example, the above-mentioned adhesive composition can be applied to a base film and dried as necessary to form an adhesive layer on the base film, which can be used as a work processing sheet. Furthermore, a release-treated surface of a release film can be attached to the exposed surface of the adhesive layer to form a work processing sheet. The release film can be removed as necessary when using the work processing sheet.

The above-mentioned adhesive composition can be applied to a release film and dried as necessary to form an adhesive layer on the release film, and the exposed surface of the adhesive layer can be bonded to one surface of a base film to form a workpiece processing sheet. In this case, the adhesive composition is preferably applied to the release-treated surface of the release film. The release film can be removed as necessary after the workpiece processing sheet is formed.

<<Dicing die bonding sheet>>
3 is a cross-sectional view showing an embodiment of the dicing die bonding sheet of the present invention. The dicing die bonding sheet 102 shown here has an adhesive layer 12 laminated on one surface 11a of a base film 11, and further has a film-like adhesive 13 on a first surface 12a of the adhesive layer 12 opposite to the base film 11. The back surface of a workpiece is attached to the film-like adhesive 13 when in use.
The workpiece processing sheet of the present invention can also be applied to the dicing die bonding sheet 102.

All layers other than the base film that make up the dicing die bonding sheet can be formed in advance on a release film and laminated by laminating it to the surface of the desired layer, so the dicing die bonding sheet can be manufactured by appropriately selecting the layers that will undergo this process as necessary.

<Film adhesive>
The film-like adhesive is not particularly limited as long as it does not impair the effects of the present invention, and any known adhesive can be used as appropriate.

The film-like adhesive is curable, preferably thermosetting, and more preferably pressure-sensitive. A film-like adhesive having both thermosetting and pressure-sensitive adhesive properties can be applied to various adherends by lightly pressing it against them in an uncured state. The film-like adhesive may also be softened by heating so that it can be applied to various adherends. The film-like adhesive eventually becomes a cured product with high impact resistance when cured, and this cured product can retain sufficient adhesive properties even under harsh conditions of high temperature and high humidity.

The film-like adhesive may consist of one layer (single layer) or may consist of two or more layers. When the film-like adhesive consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention.

The thickness of the film-like adhesive is not particularly limited, but is preferably 1 to 50 μm, and more preferably 3 to 40 μm. By having the thickness of the film-like adhesive be equal to or greater than the lower limit, a higher adhesive strength can be obtained with respect to the adherend (a workpiece such as a semiconductor chip). On the other hand, by having the thickness of the film-like adhesive be equal to or less than the upper limit, the film-like adhesive can be cut more easily in the dicing step described below, and the amount of cutting waste generated during dicing using a dicing blade can be further reduced.
Here, "thickness of the film-like adhesive" means the thickness of the entire film-like adhesive; for example, the thickness of a film-like adhesive consisting of multiple layers means the total thickness of all layers that make up the film-like adhesive.

A preferred film-like adhesive is, for example, one that contains a polymer component (a) and an epoxy-based thermosetting resin (b). The epoxy-based thermosetting resin (b) is, for example, one that is composed of an epoxy resin (b1) and a thermosetting agent (b2).
In addition, in order to improve various physical properties, the film adhesive may contain other components other than the polymer component (a) and the epoxy thermosetting resin (b) as necessary. Preferable examples of the other components include curing accelerators (c), fillers (d), coupling agents (e), crosslinking agents (f), energy ray curable resins (g), photopolymerization initiators (h), and general-purpose additives (i). The general-purpose additives (i) may be known and can be selected arbitrarily according to the purpose, and are not particularly limited. Preferable examples include plasticizers, antistatic agents, antioxidants, colorants (dyes, pigments), gettering agents, and the like.

The film-like adhesive can be formed using an adhesive composition containing its constituent materials. For example, the adhesive composition can be applied to the surface on which the film-like adhesive is to be formed, and then dried as necessary to form the film-like adhesive at the desired site. The composition and manufacturing method of the adhesive composition, and the manufacturing method of the film-like adhesive using the adhesive composition can be carried out with reference to the examples described in JP 2016-135856 A, WO 2016/140248, etc.

The dicing die bonding sheet can also be manufactured as a roll of multiple sheets, with multiple pieces of film adhesive arranged at predetermined intervals on a long sheet, by precutting the film adhesive so that it can be fixed to a ring frame of known shape.

<<Composite sheet for forming back surface protective film>>
4 is a cross-sectional view showing an embodiment of the composite sheet for forming a back surface protective film of the present invention. The composite sheet for forming a back surface protective film 103 shown here has an adhesive layer 12 laminated on one surface 11a of a base film 11, and further has a protective film forming film 14 on a first surface 12a of the adhesive layer 12 opposite to the base film 11. The composite sheet is used by attaching the back surface of a work to the protective film forming film 14.
The workpiece processing sheet of the present invention can also be applied to the composite sheet 103 for forming a back surface protective film.

The composition and manufacturing method of the protective film-forming film, and the manufacturing method of the composite sheet for forming a back surface protective film that includes the protective film-forming film can be implemented by referring to the examples described in JP 2016-015456 A and JP 2016-141749 A, etc.

<<Method of manufacturing workpiece>>
The method for manufacturing a workpiece of the present invention includes a step of attaching the workpiece processing sheet to a workpiece, and a step of dicing the workpiece to obtain a workpiece. The workpiece processing sheet includes a base film and an adhesive layer provided on the base film, and the adhesive layer contains a metal soap. Therefore, even if blade dicing is repeated in the dicing step of the workpiece, an increase in chipping size can be suppressed.

For example, FIG. 5 is a cross-sectional view showing a schematic diagram of one embodiment of the method for manufacturing a workpiece of the present invention. In the method for manufacturing a workpiece of this embodiment, the workpiece processing sheet 101 is a dicing sheet having an adhesive layer 12 on a base film 11. The method for manufacturing a workpiece of this embodiment includes a step (a) of attaching the adhesive layer 12 of the workpiece processing sheet 101 to the back surface 9b of the workpiece 9, and a dicing step (b) of blade dicing the workpiece 9 to obtain a workpiece 9'. Since the adhesive layer 12 contains metal soap, an increase in chipping size can be suppressed even if the blade dicing is repeated when the workpiece 9 is blade diced.

In another embodiment of the method for manufacturing a workpiece of the present invention, a dicing die bonding sheet is used, which comprises a workpiece processing sheet having an adhesive layer laminated on one surface of a base film, and a film-like adhesive on a first surface of the adhesive layer opposite the base film. The method for manufacturing a workpiece of this embodiment includes a step of attaching the workpiece processing sheet to the back surface of a workpiece via the film-like adhesive, and a dicing step of blade dicing the workpiece to obtain a workpiece with the film-like adhesive. Since the adhesive layer contains metal soap, an increase in chipping size can be suppressed even if blade dicing is repeated in the workpiece dicing step.

In another embodiment of the method for manufacturing a workpiece of the present invention, a composite sheet for forming a back surface protective film is used, which comprises a workpiece processing sheet having an adhesive layer laminated on one surface of a base film, and a protective film forming film on a first surface of the adhesive layer opposite the base film. The method for manufacturing a workpiece of this embodiment includes a step of attaching the workpiece processing sheet to the back surface of a workpiece via the protective film forming film, and a dicing step of blade dicing the workpiece to obtain a workpiece with a back surface protective film. Since the adhesive layer contains metal soap, an increase in chipping size can be suppressed even if blade dicing is repeated in the workpiece dicing step.

The present invention will be explained in more detail below using examples of dicing sheets as workpiece processing sheets. However, the present invention is not limited to the examples shown below.

[Example 1]
(Dicing sheet)
A pressure-sensitive adhesive composition was applied to the release-treated surface of a release film (SP-PET381031, manufactured by Lintec) and dried to form an ultraviolet-curable pressure-sensitive adhesive layer (thickness 5 μm). The exposed surface of the pressure-sensitive adhesive layer was then bonded to a base film (a polypropylene film having a thickness of 80 μm, manufactured by Mitsubishi Plastics, Inc.) to obtain a dicing sheet of Example 1.
The adhesive composition contained 33.6 parts by mass (solid content) of an acrylic copolymer (Mw: 800,000) obtained by copolymerizing 91 parts by mass of butyl acrylate and 9 parts by mass of acrylic acid, 40 parts by mass (solid content) of a penta- to 9-functional pentaerythritol-based urethane acrylate (product name "Seikabeam (registered trademark) 14-29B", manufactured by Dainichiseika Chemicals Mfg. Co., Ltd., Mw = 2,300, ratio of Mw/energy ray curable group = 328 to 460) as an ultraviolet curing resin, 5.625 parts by mass (solid content) of a tolylene diisocyanate-based crosslinking agent ("Coronate L", manufactured by Tosoh Corporation), and 1-hydroxy-cyclohexyl-phenyl-ketone (product name "OMNIRAD184", manufactured by IGM) as a photopolymerization initiator. The composition contained 1.008 parts by mass (solid content) of a metal soap containing 24.0% by mass of zirconium (trade name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation), and 0.06 parts by mass (solid content) of a metal soap containing 24.0% by mass of zirconium (trade name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation), and the solid content concentration was adjusted to 30% by mass using a mixed solvent of methyl ethyl ketone, toluene and ethyl acetate.
In the dicing sheet of Example 1, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.1058 μg/ ^cm2 .

[Example 2]
In Example 1, 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation) used in the adhesive composition was changed to 0.03 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation). A dicing sheet of Example 2 was obtained in the same manner as in Example 1.
In the dicing sheet of Example 2, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.0529 μg/ ^cm2 .

[Example 3]
In Example 1, 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation) used in the adhesive composition was changed to 0.01 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation). A dicing sheet of Example 3 was obtained in the same manner as in Example 1.
In the dicing sheet of Example 2, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.0176 μg/ ^cm2 .

[Example 4]
A dicing sheet of Example 4 was obtained in the same manner as in Example 1, except that 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation) used in the pressure-sensitive adhesive composition in Example 1 was changed to 0.07 parts by mass (solid content) of the metal soap containing 20% by mass of Zn (product name "Zn-OCTOATE 20% T" manufactured by DIC Corporation).
In the dicing sheet of Example 4, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.1029 μg/ ^cm2 .

[Example 5]
In Example 1, 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation) used in the adhesive composition was changed to 0.36 parts by mass (solid content) of the metal soap containing 4.0% by mass of Al (product name "DICNATE (registered trademark) Al-100" manufactured by DIC Corporation). A dicing sheet of Example 5 was obtained in the same manner as in Example 1.
In the dicing sheet of Example 5, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.1054 μg/ ^cm2 .

[Example 6]
A dicing sheet of Example 6 was obtained in the same manner as in Example 1, except that 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation) used in the pressure-sensitive adhesive composition in Example 1 was changed to 0.14 parts by mass (solid content) of the metal soap containing 10.0% by mass of Ni (product name "Ni-OCTOATE 10% H" manufactured by DIC Corporation).
In the dicing sheet of Example 6, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.1028 μg/ ^cm2 .

[Example 7]
In Example 1, 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation) used in the adhesive composition was changed to 0.0005 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation). A dicing sheet of Example 7 was obtained in the same manner as in Example 1.
In the dicing sheet of Example 7, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.0009 μg/ ^cm2 .

[Comparative Example 1]
A dicing sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that 0.06 parts by mass (solid content) of a metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%" manufactured by DIC Corporation) used in the adhesive composition in Example 1 was not used.
In the dicing sheet of Comparative Example 1, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.0000 μg/ ^cm2 .

[Comparative Example 2]
In Example 1, 0.06 parts by mass (solid content) of the metal soap containing 24.0% by mass of zirconium (product name "DICNATE (registered trademark) Zr 24%", manufactured by DIC Corporation) used in the adhesive composition was changed to 0.2 parts by mass (solid content) of aluminum monoacetylacetonate bis(ethylacetoacetate) (product name "Aluminum Chelate D", manufactured by Kawaken Fine Chemicals Co., Ltd.). A dicing sheet of Comparative Example 2 was obtained in the same manner as in Example 1.
In the dicing sheet of Comparative Example 2, the metal content per ^cm2 of the adhesive layer (thickness 5 μm) is 0.0698 μg/ ^cm2 .

[Evaluation of chipping during dicing]
Ten laminates were prepared by attaching the dicing sheet of Example 1 to the following workpieces (adherends), and a new blade was attached to a dicing device (DISCO Corporation, DFD-6361) and diced under the following conditions to obtain chips (i.e., workpieces).
Work (adherend): #2000 polished wafer (work size: 12 inch diameter, 200 μm thickness)
Dicing blade: Disco 27HECC
Blade rotation speed: 30,000 rpm
Dicing speed: 50 mm/s
-Cutting depth: Cut the base film to a depth of 20 μm from the interface with the adhesive layer -Dicing size: 3 mm x 3 mm

Next, after irradiating the base film with ultraviolet light (160 mJ/cm ² ), a transfer tape ("ADWILL D-210" manufactured by Lintec Corporation) was attached to the side of the workpiece on which the dicing sheet was not attached, and the workpiece was transferred from the dicing sheet to the transfer tape.
Next, the workpiece was observed from the side where the dicing sheet of the workpiece was attached using an optical microscope, and the presence or absence and size of chipping were evaluated. More specifically, among the laminates in which a new blade was attached and diced, the length of the largest chipping (chipping) occurring on the vertical and horizontal dicing lines was measured using a digital microscope (Keyence Corporation, VE-9800) for 400 pieces of workpiece transferred from the third laminate and 400 pieces of workpiece transferred from the tenth laminate. The measurement results are shown in Table 1.

For the laminates in which the dicing sheets of Examples 2 to 7 and Comparative Examples 1 and 2 were attached to the workpiece (adherend), dicing was performed using a new blade under the above dicing conditions, and similarly to the above, ultraviolet light was irradiated, the workpiece was peeled off, and the length of the largest chipping was measured. The measurement results are shown in Tables 1 to 3.

Based on the above measurement results, chipping resistance was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

<Results>
⊚: Dicing was started using a new blade, and the increase rate of the maximum chipping length of the tenth wafer (workpiece) relative to the maximum chipping length of the third wafer (workpiece) after dicing was less than 5%.
◯: Dicing was started using a new blade, and the increase rate of the maximum chipping length of the tenth wafer (workpiece) relative to the maximum chipping length of the third wafer (workpiece) was less than 15%.
Δ: Dicing was started using a new blade, and the increase rate of the maximum chipping length of the tenth wafer (workpiece) relative to the maximum chipping length of the third wafer (workpiece) was 15% or more and less than 30%.
×: Dicing was started using a new blade, and the increase rate of the maximum chipping length of the tenth wafer (workpiece) relative to the maximum chipping length of the third wafer (workpiece) after dicing was 30% or more.

As shown in Tables 1 to 3, the dicing sheet as a workpiece processing sheet of the present invention comprises a base film and an adhesive layer provided on the base film, the adhesive layer contains metal soap, and the metal content per area of the adhesive layer is 0.0004 μg/ ^cm2 or more. Therefore, it can be seen that, in the workpiece dicing process, even if dicing is started using a new blade and then blade dicing is repeated, an increase in chipping size can be suppressed.

The workpiece processing sheet of the present invention, the dicing die bonding sheet comprising the workpiece processing sheet, and the composite sheet for forming a back surface protective film comprising the workpiece processing sheet can be used for manufacturing semiconductor devices. The workpiece processing sheet of the present invention can also be used as a back grinding tape.

101, 101': Workpiece processing sheet (dicing sheet), 102: Dicing die bonding sheet, 103: Composite sheet for forming backside protective film, 11: Base film, 11a: First surface of base film, 12: Adhesive layer, 12a: First surface of adhesive layer, 13: Film-like adhesive, 14: Film for forming protective film, 9: Workpiece, 9a: Circuit surface of workpiece, 9b: Backside of workpiece, 9': Workpiece processed product, 9a': Circuit surface of workpiece processed product

Claims (6)

A substrate film and a pressure-sensitive adhesive layer provided on the substrate film,
The pressure-sensitive adhesive layer contains a metal soap,
A workpiece processing sheet, in which the metal content per area of the adhesive layer is 0.0004 μg/ ^cm2 or more (excluding those in which the adhesive layer contains spherical adhesive) . The workpiece processing sheet according to claim 1, wherein the metal soap is a fatty acid zirconium salt, a fatty acid zinc salt, a fatty acid aluminum salt, or a fatty acid nickel salt. The workpiece processing sheet according to claim 1 or 2, wherein the number of carbon atoms of the fatty acid in the fatty acid metal salt as the metal soap is 5 to 20. The workpiece processing sheet according to any one of claims 1 to 3,
A dicing die bonding sheet comprising a film-like adhesive on a first surface of the pressure-sensitive adhesive layer opposite the base film. The workpiece processing sheet according to any one of claims 1 to 3,
A composite sheet for forming a back surface protective film, comprising a film for forming a protective film on a first surface of the pressure-sensitive adhesive layer opposite the base film. A step of attaching the workpiece processing sheet according to any one of claims 1 to 3 to the back surface of a workpiece;
and a dicing step of blade dicing the work to obtain a work piece.

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