KR20230138861A - Adhesive sheet and method of manufacturing semiconductor device - Google Patents

Abstract

(Problem) To provide an adhesive sheet that is capable of holding a workpiece satisfactorily and is capable of separating the workpiece satisfactorily without requiring irradiation of active energy rays.
(Solution) A pressure-sensitive adhesive sheet for handling a workpiece, comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer is an inert adhesive composition containing at least an acrylic polymer and a tackifier. An adhesive sheet made of an energy-ray curable adhesive, wherein the tackifier is an alkylene glycol-modified rosin ester.

Description

Manufacturing method of adhesive sheet and semiconductor device {ADHESIVE SHEET AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE}

The present invention relates to an adhesive sheet for handling workpieces such as semiconductor wafers and semiconductor chips, and particularly to an adhesive sheet that can be suitably used for sorting, inspecting, rearranging, storing, shipping, and transporting the workpieces. will be.

Semiconductor wafers such as silicon and gallium arsenide and semiconductor packages made of semiconductor components encapsulated in resin are manufactured in a large diameter state, cut into chips (diced), peeled (picked up), and then It is moved to the mount process. At this time, the work such as a semiconductor wafer or semiconductor package is laminated on an adhesive sheet equipped with a base material and an adhesive layer, and is subjected to back-grinding, dicing, cleaning, drying, expanding, pickup, mounting, etc. Processing is carried out.

In the above-described adhesive sheet, the adhesive layer may be made of an adhesive having active energy ray curability. In this case, by irradiating the adhesive layer with active energy rays, the adhesive force of the adhesive layer to the work can be reduced, thereby making it possible to easily separate (for example, pick up) the work from the adhesive sheet. It becomes. Patent Documents 1 and 2 disclose examples of such adhesive sheets.

Japanese Patent No. 6782237 Japanese Patent No. 5032740

In recent years, in order to sort out workpieces such as semiconductor chips, the workpieces may be temporarily attached to an adhesive sheet. In this case, for example, only those of excellent quality are selected from a plurality of semiconductor chips stacked on one adhesive sheet and transferred to another adhesive sheet. Accordingly, it becomes possible to ship, store, etc. only semiconductor chips of excellent quality.

The adhesive sheet used for the above sorting purpose has the ability to sufficiently retain workpieces such as semiconductor chips and the ability to easily separate the workpiece to be separated (hereinafter referred to as “easy peelability”). Yes) is required.

Here, the adhesive sheet in which the adhesive layer is composed of the adhesive having active energy ray curability described above can also be used for the above-described screening purpose. However, the adhesive sheet requires irradiation of active energy rays to the adhesive layer when separating the work, which increases the number of steps during handling and increases manufacturing costs. In addition, it is realistically difficult to irradiate active energy rays with a pin point to the position of the work to be separated, and therefore, it is not suitable for use such as separating only a part of the work and leaving the other work on the adhesive sheet.

The present invention has been made in consideration of such actual conditions, and its purpose is to provide an adhesive sheet that is capable of holding a work satisfactorily and is capable of separating the work well without requiring irradiation of active energy rays.

In order to achieve the above object, firstly, the present invention is an adhesive sheet for handling a work, comprising a base material and an adhesive layer laminated on one side of the base material, wherein the adhesive layer contains an acrylic polymer and a tackifier. An adhesive sheet is provided, which is made of an inert energy ray-curable adhesive formed from an adhesive composition containing at least and wherein the tackifier is an alkylene glycol-modified rosin ester (invention 1).

In the adhesive sheet according to the invention (invention 1), the adhesive layer is made of an inert energy ray-curable adhesive formed from the adhesive composition described above, and in particular, by using an alkylene glycol-modified rosin ester as a tackifier, the workpiece is maintained in good condition. In addition to being able to maintain the workpiece, the desired workpiece can be easily separated without requiring irradiation of active energy rays.

In the above invention (invention 1), the content of the alkylene glycol modified rosin ester as the tackifier in the adhesive composition is preferably 0.01 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the acrylic polymer ( Invention 2).

In the above inventions (inventions 1 and 2), the adhesive composition contains a crosslinking agent, and the content of the crosslinking agent in the adhesive composition is preferably 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the acrylic polymer. Do (Invention 3).

In the above inventions (inventions 1 to 3), the adhesive force to the mirror surface of the silicon wafer is preferably 200 mN/25 mm or more and 3000 mN/25 mm or less (invention 4).

In the above inventions (inventions 1 to 4), for a 10 mm When removing the silicon chip from the adhesive sheet by sucking the silicon chip with a vacuum collet measuring 9.9 mm × 9.9 mm while pushing the silicon chip up using a needle, the push-up required for the removal The minimum height is preferably 750 ㎛ or less (invention 5).

Secondly, the present invention includes a process of attaching one or a plurality of works to the surface of the adhesive sheet (inventions 1 to 5) on the adhesive layer side, separating at least one of the works from the adhesive sheet, A method for manufacturing a semiconductor device is provided, which includes a step of mounting it on a predetermined object (invention 6).

The adhesive sheet according to the present invention is capable of holding the work satisfactorily and is capable of separating the work well without requiring irradiation of active energy rays.

Hereinafter, embodiments of the present invention will be described.

The adhesive sheet according to this embodiment includes a base material and an adhesive layer laminated on one side of the base material. In the adhesive sheet according to the present embodiment, the adhesive layer is made of an inert energy ray-curable adhesive formed of an adhesive composition containing at least an acrylic polymer and a tackifier. Additionally, the tackifier is an alkylene glycol-modified rosin ester.

As described above, the pressure-sensitive adhesive sheet according to the present embodiment can exhibit sufficient adhesive strength to the workpiece because the pressure-sensitive adhesive layer is made of an adhesive formed of an adhesive composition containing at least an acrylic polymer and a tackifier. Therefore, for example, even when a plurality of works such as semiconductor chips are laminated on the side of the adhesive layer opposite to the base material (hereinafter sometimes referred to as “adhesive side”), detachment occurs. By preventing misalignment, each workpiece can be sufficiently maintained.

On the other hand, in the adhesive sheet according to the present embodiment, the work to be separated can be easily separated from the adhesive sheet by using alkylene glycol-modified rosin ester as the tackifier. And this easy peeling property can be achieved without irradiation of active energy rays. Therefore, the adhesive sheet according to the present embodiment can easily separate the intended workpiece without increasing the equipment or processes for irradiating active energy rays.

As described above, the adhesive sheet has both excellent adhesive strength and easy peelability, so that, for example, when multiple semiconductor chips are attached to the adhesive sheet, adjacent chips do not fall off or become misaligned. , only certain chips can be separated well. Therefore, according to the adhesive sheet according to this embodiment, it becomes possible to selectively pick up a predetermined thing from a plurality of semiconductor chips.

In addition, the adhesive sheet according to the present embodiment can maintain the above-mentioned easy peelability even after a long period of time has elapsed since the work is attached. In particular, according to the adhesive sheet according to the present embodiment, excellent easy peelability can be achieved without irradiation of active energy rays even after a long period of time has elapsed since the work is attached. Therefore, the adhesive sheet according to this embodiment is also suitable for uses such as storing a plurality of semiconductor chips in an attached state, for example.

1. Description

The base material in this embodiment is not particularly limited as long as it exhibits the desired function when using the adhesive sheet. In particular, it is preferable that the base material is a resin film based on a resin-based material. Specific examples thereof include polyolefin-based films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; Polyester-based films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; Ethylene-vinyl acetate copolymer film; Ethylene-based copolymer films such as ethylene-(meth)acrylic acid copolymer film, ethylene-methyl (meth)acrylate copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; Polyvinyl chloride-based films such as polyvinyl chloride film and vinyl chloride copolymer film; (meth)acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; A fluororesin film, etc. can be mentioned. Additionally, modified films such as these crosslinked films and ionomer films are also used. In addition, the base material may be a laminated film formed by laminating multiple films described above. In this laminated film, the materials constituting each layer may be of the same type or may be of different types. In addition, “(meth)acrylic acid” in this specification means both acrylic acid and methacrylic acid. The same goes for other similar terms. In addition, “polymer” in this specification also includes the concept of “copolymer.”

The base material may contain various additives such as a flame retardant, a plasticizer, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet ray absorber, and an ion trap. The content of these additives is not particularly limited, but is preferably within a range that allows the base material to exhibit the desired function. In addition, the base material in this embodiment may contain an antistatic agent, but it is also preferable not to contain an antistatic agent.

The surface of the substrate on which the adhesive layer is laminated may be subjected to surface treatment such as primer treatment, corona treatment, or plasma treatment in order to increase adhesion to the adhesive layer.

The thickness of the base material can be appropriately set depending on the method in which the adhesive sheet is used, but for example, it is preferably 200 μm or less, and especially preferably 150 μm or less. Additionally, the thickness of the base material is preferably 10 μm or more, and particularly preferably 25 μm or more.

2. Adhesive layer

As described above, the adhesive layer in this embodiment is made of an adhesive formed from an adhesive composition containing at least an acrylic polymer and a tackifier. It is also preferable that the adhesive composition further contains a crosslinking agent.

(1) Acrylic polymer

As the acrylic polymer, a conventionally known acrylic polymer can be used. The acrylic polymer may be a homopolymer formed from one type of acrylic monomer, a copolymer formed from multiple types of acrylic monomers, or a copolymer formed from one type or multiple types of acrylic monomer and a monomer other than the acrylic monomer.

From the viewpoint that the adhesive sheet according to the present embodiment can easily exhibit the desired adhesive strength, the acrylic polymer includes, as monomer units constituting the polymer, an alkyl (meth)acrylate ester, a monomer having a polar group (polar group-containing monomer), It is preferable to include a monomer having a functional group (functional group-containing monomer).

The acrylic polymer can easily achieve the desired adhesive strength by containing the above-mentioned (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer. As the (meth)acrylic acid alkyl ester, those in which the alkyl group has 1 to 18 carbon atoms are preferable, and those in which the alkyl group has 1 to 8 carbon atoms are particularly preferable. Specific examples of the above (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, and n-(meth)acrylate. -hexyl, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, (meth)acrylate ) Stearyl acrylate, etc. can be mentioned. These may be used individually, or two or more types may be used in combination.

The acrylic polymer preferably contains 70% by mass or more of alkyl (meth)acrylate as the monomer unit constituting the polymer, particularly preferably 75% by mass or more, and more preferably 80% by mass or more. do. In addition, the acrylic polymer preferably contains 97% by mass or less of alkyl (meth)acrylate as a monomer unit constituting the polymer, particularly preferably 95% by mass or less, and more preferably 92% by mass. It is preferable to contain the following. When the content of (meth)acrylic acid alkyl ester is within the above range, it becomes easy to achieve the desired adhesive strength.

The acrylic polymer is a monomer unit constituting the polymer, and by containing the above-described polar group-containing monomer, the polarity of the resulting pressure-sensitive adhesive is improved, making it easy to achieve sufficient adhesion when using a silicon wafer as a workpiece. Examples of polar group-containing monomers include methyl methacrylate, acryloylmorpholine, isobornyl acrylate, vinyl acetate, benzyl acrylate, and glycidyl methacrylate. Among these, methyl methacrylate is particularly used. It is desirable to do so.

When the acrylic polymer contains a polar group-containing monomer as a monomer unit constituting the polymer, the acrylic polymer preferably contains 1% by mass or more of the polar group-containing monomer, and especially preferably contains 3% by mass or more. It is preferable to contain 5% by mass or more. In addition, the acrylic polymer preferably contains 30% by mass or less of a polar group-containing monomer as a monomer unit constituting the polymer, especially preferably 20% by mass or less, and more preferably 15% by mass or less. It is desirable to contain it. When the content of the polar group-containing monomer is within the above range, the pressure-sensitive adhesive layer easily exhibits the desired polarity.

The acrylic polymer contains the functional group-containing monomer as the monomer unit constituting the polymer, and reacts with a cross-linking agent described later through the functional group derived from the functional group-containing monomer to form a cross-linked structure (three-dimensional network structure). there is. Accordingly, an adhesive having the desired cohesive strength is obtained.

The functional group-containing monomer is preferably a monomer that has a polymerizable double bond and a functional group such as a hydroxy group, carboxyl group, amino group, substituted amino group, or epoxy group in the molecule. Among these, from the viewpoint of excellent reactivity with a crosslinking agent, monomers having a hydroxy group in the molecule (monomer containing a hydroxy group), monomers having a carboxyl group in the molecule (monomer containing a carboxyl group), monomers having an amino group in the molecule (monomer containing an amino group), etc. It is desirable to use

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, Examples include 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., and these are used individually or in combination of two or more types.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used individually, or two or more types may be used in combination.

The acrylic polymer preferably contains 3% by mass or more of a functional group-containing monomer as the monomer unit constituting the polymer, particularly preferably 4% by mass or more, and more preferably 5% by mass or more. In addition, the acrylic polymer preferably contains 30% by mass or less of functional group-containing monomer as the monomer unit constituting the polymer, especially preferably contains 25% by mass or less, and more preferably contains 20% by mass or less. It is desirable to do so. When the content of the functional group-containing monomer is within the above range, the resulting adhesive tends to have the desired cohesive force.

The acrylic polymer may contain other monomers in addition to the above-mentioned (meth)acrylic acid alkyl ester, polar group-containing monomer, and functional group-containing monomer as monomer units constituting the polymer.

Examples of the other monomers include alkoxyalkyl group-containing (meth)acrylic acid esters such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate. ; (meth)acrylic acid esters having an aliphatic ring such as cyclohexyl (meth)acrylate; (meth)acrylic acid esters having an aromatic ring such as phenyl (meth)acrylate; Monomers having nitrogen-containing heterocycles such as N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, and N-(meth)acryloylpyrrolidone; Non-crosslinkable acrylamides such as (meth)acrylamide and N,N-dimethyl (meth)acrylamide; (meth)acrylic acid esters having a non-crosslinkable tertiary amino group such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; Vinyl acetate; Styrene, etc. can be mentioned.

The polymerization mode of the acrylic polymer may be a random copolymer or a block copolymer. In addition, the polymerization method is not particularly limited, and polymerization can be performed according to a general polymerization method, for example, a solution polymerization method.

The weight average molecular weight (Mw) of the acrylic polymer is preferably 300,000 or more, particularly preferably 400,000 or more, and more preferably 500,000 or more. Furthermore, the weight average molecular weight (Mw) is preferably 1.5 million or less, especially 1.2 million or less, and more preferably 1 million or less. When the weight average molecular weight (Mw) of the acrylic polymer is within the above range, an adhesive having an excellent balance between adhesive strength and easy peelability can be easily obtained. In addition, the weight average molecular weight (Mw) in this specification is a standard polystyrene conversion value measured according to the gel permeation chromatography method (GPC method).

(2) Tackifier

As described above, the tackifier in this embodiment is alkylene glycol-modified rosin ester. The alkylene glycol-modified rosin ester is not particularly limited, but is preferably obtained by, for example, esterifying rosins, polyalkylene glycol monoalkyl ethers, polyhydric alcohols, and α,β-unsaturated carboxylic acids.

Additionally, as the alkylene glycol-modified rosin ester, it is preferable to use one whose softening point is 50°C or lower, especially preferably 20°C or lower, and even more preferably 0°C or lower. When the softening point is 50°C or lower, the alkylene glycol-modified rosin ester has higher fluidity and the desired adhesive strength can be easily achieved. Moreover, the lower limit of the softening point is not particularly limited, and is preferably -100°C or higher, especially preferably -70°C or higher, and more preferably -40°C or higher.

In addition, as the alkylene glycol-modified rosin ester, it is preferable to use one whose weight average molecular weight is 1000 or more, particularly preferably 2000 or more, and even more preferably 3000 or more. When the weight average molecular weight is 1000 or more, the compatibility of the alkylene glycol-modified rosin ester with other components in the adhesive composition tends to decrease moderately, making it easy to achieve the desired adhesive strength. Moreover, from the viewpoint of compatibility with the adhesive composition, the upper limit of the weight average molecular weight is preferably 1 million or less, more preferably 100,000 or less, especially 50,000 or less, and further preferably 8,000 or less.

The content of alkylene glycol-modified rosin ester as a tackifier in the adhesive composition is preferably 0.01 parts by mass or more, particularly preferably 0.1 parts by mass or more, and more preferably 0.2 parts by mass or more, based on 100 parts by mass of the acrylic polymer. desirable. When the content is 0.01 parts by mass or more, it becomes easy to achieve more excellent easy peeling properties. Furthermore, the content is preferably 5.0 parts by mass or less, especially 4.0 parts by mass or less, and more preferably 3.0 parts by mass or less, based on 100 parts by mass of the acrylic polymer. When the content is 5.0 parts by mass or less, it is easy to achieve excellent adhesive strength.

(3) Cross-linking agent

The crosslinking agent may be one that reacts with the functional group of the acrylic copolymer, for example, isocyanate crosslinking agent, epoxy crosslinking agent, amine crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent. Crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, and ammonium salt-based crosslinking agents can be mentioned. Moreover, the crosslinking agent can be used individually or in combination of two or more types.

Here, when the acrylic copolymer contains a hydroxy group-containing monomer as a constituent monomer unit, it is preferable to use an isocyanate-based cross-linking agent having excellent reactivity with hydroxy groups as the cross-linking agent.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. Alicyclic polyisocyanates such as isocyanates, and their biuret and isocyanurate forms, as well as reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. A duct body, etc. can be mentioned. Among them, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates, especially trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate, are preferable.

The compounding amount of the crosslinking agent is preferably 0.1 part by mass or more, particularly preferably 1 part by mass or more, and more preferably 3 parts by mass or more, based on 100 parts by mass of the acrylic copolymer. Additionally, the amount of the crosslinking agent mixed is preferably 20 parts by mass or less, particularly preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, based on 100 parts by mass of the acrylic copolymer. When the compounding amount of the crosslinking agent is within the above range, an adhesive having a predetermined adhesive force and a crosslinking density suitable for pick-up properties is obtained.

(4) Other

The adhesive composition in the present embodiment may contain desired additives, such as silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, Softeners, fillers, refractive index adjusters, etc. can be added. In addition, the polymerization solvent and dilution solvent described later are not included in the additives constituting the adhesive composition.

(5) Method for preparing adhesive composition

The adhesive composition in this embodiment can be produced by producing an acrylic copolymer and mixing the obtained acrylic copolymer, a tackifier, and, if desired, a crosslinking agent and other components.

Acrylic copolymers can be produced by polymerizing a mixture of monomers constituting the polymer using a normal radical polymerization method. The polymerization is preferably carried out according to the solution polymerization method using a polymerization initiator as desired. Examples of polymerization solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc., and two or more types may be used in combination.

Examples of polymerization initiators include azo-based compounds and organic peroxides, and two or more types may be used in combination. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexane 1-carbon). tril), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl2,2'- Azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'- Azobis[2-(2-imidazoline-2-yl)propane] etc. can be mentioned.

Organic peroxides include, for example, benzoyl peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, and di(2-ethoxyethyl)peroxydicarbonate. , t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide, etc.

Additionally, in the polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by mixing a chain transfer agent such as 2-mercaptoethanol.

Once the acrylic copolymer is obtained, an active energy ray-curable component, a tackifier, and, if desired, a crosslinking agent, other components, and a diluting solvent are added to the solution of the acrylic copolymer, and thoroughly mixed to form a coating liquid of the adhesive composition. can be obtained. In addition, when using any of the above components in solid form, or when precipitation occurs when mixed with other components in an undiluted state, the component must be dissolved or diluted individually in a diluting solvent beforehand. , may be mixed with other ingredients.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, butanol, and 1-mer. Alcohols such as toxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolve solvents such as ethyl cellosolve, etc. This is used.

The concentration and viscosity of the coating liquid prepared in this way are not particularly limited as long as it is within a range that can be coated, and can be appropriately selected depending on the situation. For example, the adhesive composition is diluted so that the concentration is 10% by mass or more and 60% by mass or less. In addition, in obtaining the coating liquid, addition of a diluting solvent, etc. is not a necessary condition, and if the adhesive composition has a coatingable viscosity, etc., it is not necessary to add a diluting solvent. In this case, the adhesive composition becomes a coating liquid in which the polymerization solvent of the acrylic copolymer is used as a dilution solvent.

(6) Thickness of adhesive layer

The thickness of the adhesive layer in this embodiment is preferably 1 μm or more, particularly preferably 2 μm or more, and more preferably 3 μm or more. When the thickness of the adhesive layer is 1 μm or more, it becomes easy for the adhesive sheet to achieve good adhesive strength. Additionally, the thickness is preferably 50 μm or less, particularly preferably 30 μm or less, and more preferably 20 μm or less. When the thickness of the adhesive layer is 20 μm or less, it becomes easy for the adhesive sheet to achieve good easy peelability.

3. Other configurations

(1) Release sheet

In the adhesive sheet according to this embodiment, a release sheet may be laminated on the adhesive surface for the purpose of protecting the adhesive surface of the adhesive layer until the adhesive surface is attached to the work. The configuration of the release sheet is arbitrary, and an example is one in which a plastic film has been subjected to a release treatment using a release agent or the like. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based releasers, etc. can be used, and among these, a silicone-based releaser is preferable as it is inexpensive and provides stable performance. There is no particular limitation on the thickness of the release sheet, but it is usually 20 μm or more and 250 μm or less.

(2) Adhesive layer

In the adhesive sheet according to this embodiment, an adhesive layer may be laminated on the side of the adhesive layer opposite to the base material. In this case, the adhesive sheet according to this embodiment can be used as a dicing/die bonding sheet. In the above sheet, a chip in which the separated adhesive layers are laminated can be obtained by attaching a work to the side of the adhesive layer opposite to the adhesive layer and dicing the adhesive layer together with the work. The chip can be easily fixed to the object on which the chip is mounted by this separate adhesive layer. As the material constituting the above-mentioned adhesive layer, it is preferable to use a material containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material containing a B stage (semi-cured burn) thermosetting adhesive component.

(3) Protective film cambium layer

In addition, in the adhesive sheet according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the adhesive sheet according to this embodiment can be used as a sheet for forming a protective film and for dicing. In such a sheet, a chip in which the separate protective film forming layers are laminated can be obtained by attaching a work to the side of the protective film forming layer opposite to the adhesive layer and dicing the protective film forming layer together with the work. As the work, it is preferable to use one on which a circuit is formed on one side, and in this case, a protective film forming layer is usually laminated on the side opposite to the side on which the circuit is formed. By curing the separated protective film forming layer at a predetermined timing, a protective film with sufficient durability can be formed on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

4. Physical properties

(1) Minimum push-up height

In the adhesive sheet according to the present embodiment, a 10 mm When removing the silicon chip from the adhesive sheet by suctioning it with a vacuum collet measuring 9.9 mm It is preferable that it is 550 μm or less, and even more preferably 500 μm or less. According to the adhesive sheet according to the present embodiment, the above-mentioned minimum push-up height can be achieved by using alkylene glycol-modified rosin ester as a tackifier. And, when the minimum push-up height is within the above range, it becomes easy to separate the work. Additionally, the lower limit of the minimum push-up height is not particularly limited, and may be, for example, 50 μm or more.

In addition, in the adhesive sheet according to the present embodiment, a 10 mm When removing the silicon chip from the adhesive sheet by suctioning it with a vacuum collet measuring 9.9 mm It is preferably 750 μm or less, especially 550 μm or less, and even more preferably 500 μm or less. According to the adhesive sheet according to the present embodiment, by using alkylene glycol-modified rosin ester as a tackifier, the above-mentioned minimum push-up height can be achieved even after a long period of 3 months has elapsed from sticking. And, when the minimum push-up height is within the above range, it becomes easy to separate the work. Additionally, the lower limit of the minimum push-up height is not particularly limited, and may be, for example, 50 μm or more.

In addition, the details of the method for measuring the above-mentioned minimum push-up height are as described in the test example described later.

(2) Adhesion

In the adhesive sheet according to this embodiment, the adhesive force to the mirror surface of the silicon wafer is preferably 200 mN/25 mm or more, particularly preferably 300 mN/25 mm or more, and more preferably 400 mN/25 mm or more. When the adhesive force is 200 mN/25 mm or more, it becomes easy to maintain the work well on the adhesive sheet. Additionally, the adhesive force is preferably 3000 mN/25 mm or less, especially 2000 mN/25 mm or less, and more preferably 1500 mN/25 mm or less. When the adhesive force is 3000 mN/25 mm or less, it becomes easy to achieve the minimum push-up height mentioned above. In addition, the details of the method for measuring the adhesive force are as described in the test examples described later.

5. Manufacturing method of adhesive sheet

The manufacturing method of the pressure-sensitive adhesive sheet according to this embodiment is not particularly limited, and is preferably manufactured by laminating a pressure-sensitive adhesive layer on one side of the substrate.

Lamination of the adhesive layer on one side of the substrate can be performed according to a known method. For example, it is preferable to transfer the adhesive layer formed on the release sheet to one side of the substrate. In this case, a coating liquid further containing the adhesive composition constituting the adhesive layer and a solvent or dispersion medium as desired is prepared, and applied on the peeled surface of the release sheet (hereinafter sometimes referred to as “release surface”), An adhesive layer can be formed by applying the coating liquid using a die coater, curtain coater, spray coater, slit coater, knife coater, applicator, etc. to form a coating film, and drying the coating film. The coating liquid is not particularly limited in its properties as long as it can be applied, and may contain components for forming an adhesive layer as a solute or as a dispersoid. The release sheet in this laminate may be peeled off as a process material, or may be used to protect the adhesive surface of the adhesive layer until the adhesive sheet is attached to the adherend.

When the coating solution for forming the adhesive layer contains a crosslinking agent, a crosslinking reaction between the acrylic copolymer in the coating film and the crosslinking agent is achieved by changing the above drying conditions (temperature, time, etc.) or by providing a separate heat treatment. This may be carried out to form a crosslinked structure at the desired density within the adhesive layer. In order to sufficiently advance this crosslinking reaction, after laminating an adhesive layer on a base material by the method described above, etc., the obtained adhesive sheet is left to stand in an environment of, for example, 23°C and 50% relative humidity for several days. You may perform curing.

Instead of transferring the adhesive layer formed on the release sheet as described above to one side of the substrate, the adhesive layer may be formed directly on the substrate. In this case, the coating liquid for forming the adhesive layer described above is applied to one side of the substrate to form a coating film, and the coating film is dried to form the adhesive layer.

6. How to use the adhesive sheet

The adhesive sheet according to this embodiment can be used for handling workpieces such as semiconductor chips. Specifically, it can be used for selection, rearrangement, inspection, storage, shipping, and return of workpieces such as semiconductor chips.

For example, when selecting works, generally only works that meet a predetermined standard are transferred from one adhesive sheet to another adhesive sheet, but the adhesive sheet according to the present embodiment includes the one adhesive sheet and the adhesive sheet according to the present embodiment. Any of the other adhesive sheets mentioned above can be used. Additionally, the works can also be rearranged by laminating the works laminated on the adhesive sheet or the like in a predetermined arrangement on the adhesive sheet according to the present embodiment. Additionally, with the work being laminated on the adhesive sheet according to this embodiment, the work can be inspected, stored, shipped, transported, etc.

Additionally, the adhesive sheet according to this embodiment can also be used for processing workpieces such as semiconductor wafers. That is, after attaching the adhesive surface of the adhesive sheet according to this embodiment to the work, the work can be processed on the adhesive sheet. According to the above processing, the adhesive sheet according to this embodiment is used as a backgrinding sheet, dicing sheet, expand sheet, pickup sheet, etc.

In addition, when the adhesive sheet according to this embodiment is provided with the adhesive layer described above, the adhesive sheet can be used as a dicing/die-bonding sheet. Additionally, when the adhesive sheet according to the present embodiment is provided with the protective film forming layer described above, the adhesive sheet can be used as a protective film forming and dicing sheet.

What can be used as a work in the adhesive sheet according to this embodiment is not particularly limited, and examples include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

When using the above-described semiconductor member as a work, the adhesive sheet according to this embodiment is also preferably used in a semiconductor device manufacturing method. The manufacturing method includes, for example, a step of attaching one or a plurality of works to the surface on the adhesive layer side of the adhesive sheet according to the present embodiment, separating at least one of the works from the adhesive sheet, A process for positioning a device on a predetermined target is provided. In addition, known methods can be used for the above-mentioned attachment and separation.

The embodiments described above are described to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, another layer may be provided between the substrate and the adhesive layer, or on the surface of the substrate opposite to the adhesive layer.

[Example]

Hereinafter, the present invention will be described in more detail through examples, etc., but the scope of the present invention is not limited to these examples.

[Example 1]

(1) Production of acrylic polymer

78 parts by mass of 2-ethylhexyl acrylate, 12 parts by mass of methyl acrylate, and 10 parts by mass of 2-hydroxyethyl acrylate were polymerized according to a solution polymerization method to obtain an acrylic polymer. The weight average molecular weight (Mw) of this acrylic polymer was 800,000.

(2) Production of tackifier

711 g of gum rosin, 107 g of glycerin, 189 g of fumaric acid, 2,100 g of polypropylene glycol with a weight average molecular weight of 1,000, and 150 g of xylene were added to the flask, purged with nitrogen, and heated at 280°C for 13 hours while stirring. Afterwards, xylene was removed under reduced pressure at 200°C for 20 minutes. Next, the contents were taken out from the flask, cooled to room temperature, and solidified to obtain alkylene glycol-modified rosin ester as a tackifier.

(3) Preparation of adhesive composition

100 parts by mass of the acrylic polymer obtained in (1) above (solid content conversion value; the same below), 0.075 parts by mass of alkylene glycol-modified rosin ester as a tackifier obtained in (2) above, and trimethylolpropane-modified tolylenedi as a crosslinking agent. 4.69 parts by mass of isocyanate (manufactured by TOSOH CORPORATION, product name "Colonate L") was mixed in a solvent to obtain a coating liquid of an adhesive composition with a solid content concentration of 30% by mass.

(4) Formation of adhesive layer

A coating liquid of the adhesive composition prepared in (3) above on the peeling surface of a release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") in which a silicone-based release agent layer is formed on one side of a polyethylene terephthalate film with a thickness of 38 μm. was applied using a comma coater and dried by heating at 100°C for 1 minute to form an adhesive layer with a thickness of 5 μm on the release sheet.

(5) Production of adhesive sheet

After attaching the exposed side of the adhesive layer formed in (4) above and one side of the ethylene-methacrylic acid copolymer film with a thickness of 80 μm as a substrate, the mixture is left to stand for one week in an environment of 23° C. and 50% relative humidity. An adhesive sheet was obtained.

Here, the weight average molecular weight (Mw) described above is the weight average molecular weight in terms of standard polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.

<Measurement conditions>

·GPC measuring device: manufactured by TOSOH CORPORATION, HLC-8320

·GPC column (passed in the following order): manufactured by TOSOH CORPORATION

TSK gel superH-H

TSK gel superHM-H

TSK gel superH2000

·Measurement solvent: tetrahydrofuran

·Measurement temperature: 40℃

[Examples 2 to 10 and Comparative Examples 1 to 7]

An adhesive sheet was obtained in the same manner as in Example 1, except that the composition of the adhesive composition was changed as shown in Tables 1 and 2.

In addition, details such as abbreviations shown in Table 1 and Table 2 are as follows.

2EHA: 2-ethylhexyl acrylate

MMA: Methyl methacrylate

HEA: 2-hydroxyethyl acrylate

BA: Butyl acrylate

Alcon M-90: Hydrogenated petroleum resin (manufactured by Arakawa Chemical Industries, Ltd., product name “Alcon M-90”)

YS Polystar K125: Terpene phenol resin (manufactured by YASUHARA CHEMICAL CO., LTD., product name “YS Polystar K125”)

YS Polystar U115: Terpene phenol resin (manufactured by YASUHARA CHEMICAL CO., LTD., product name “YS Polystar U115”)

Ester gum AA-G: Rosin ester (manufactured by Arakawa Chemical Industries, Ltd., product name “Ester gum AA-G”)

Pinecrystal KE-100: Super light-colored rosin ester (manufactured by Arakawa Chemical Industries, Ltd., product name “Pinecrystal KE-100”)

[Test Example 1] (Evaluation of easy peelability)

The release sheet was peeled from the adhesive sheets prepared in Examples and Comparative Examples to expose the adhesive layer. Then, the exposed surface of the adhesive layer exposed as described above was attached to the polished surface of the #2000 polished silicon wafer using a tape mounter (“Adwill RAD2510F/12” manufactured by LINTEC Corporation). Next, a ring frame for dicing was attached to the peripheral portion of the exposed surface of the adhesive sheet (a position that does not overlap with the silicon wafer). Additionally, the adhesive sheet was cut to fit the outer diameter of the ring frame.

After that, using a dicing device (manufactured by DISCO CORPORATION, product name "DFD6362"), the silicon wafer was diced on the adhesive sheet under the following conditions, and was divided into individual silicon chips of 10 mm x 10 mm in size.

<Dicing conditions>

Wafer thickness: 150㎛

Blade: ZH05-SD2000-N1-90 CC

Blade rotation speed: 35000rpm

Feed speed: 50㎜／min

Blade height: 0.06mm

Cutting water volume: 1.0L/min

Cutting water temperature: 20℃

At the point when 24 spans have elapsed after attaching a silicon wafer to the adhesive sheet, a pick-up device (manufactured by Canon Machinery Inc., product name “BESTEM D-510”) is used for one chip located near the center of the adhesive sheet when viewed from the top. "), at room temperature, using four push-up pins, the push-up speed is set to 20 mm/sec, the holding time is set to 0.1 msec, and the push-up amount is changed in the range of 300 to 1000 ㎛, and the chip A push-up was performed. Simultaneously with the above pushing up, an attempt was made to remove the chip from the adhesive sheet using a vacuum collet with a size of 9.9 mm x 9.9 mm. The minimum value of the push-up height (㎛) when these chips can be picked up three times in a row without abnormalities by repeating the push-up and removal with a collet while changing the push-up amount in stages. saved. The above minimum values are shown in Tables 1 and 2 as the minimum push-up height (μm) 24 hours after sticking.

In addition, when 3 months had passed since the silicon wafer was attached to the adhesive sheet, the minimum push-up height (μm) was measured in the same manner as above. This is shown in Tables 1 and 2 as the minimum push-up height (μm) three months after sticking.

Moreover, in either case, 24 hours after sticking or 3 months after sticking, when the minimum push-up height is 650 μm or less, even if pickup can be easily performed, easy peelability is excellent.

[Test Example 2] (Measurement of adhesive force)

The adhesive sheets manufactured in Examples and Comparative Examples were cut into strips with a width of 25 mm. A 2 kg rubber roller was applied to the mirror surface of a silicon wafer obtained by peeling off the release sheet from the obtained single-layer adhesive sheet and mirror-finishing the exposed adhesive surface of the adhesive layer, under an environment of a temperature of 23°C and a relative humidity of 50%. It was attached using , left to stand for 20 minutes, and used as a sample for measurement.

For the obtained measurement sample, an adhesive sheet was peeled from a silicon wafer using a universal tensile tester (manufactured by Orientec Inc., product name "Tensilon UTM-4-100") at a peeling speed of 300 mm/min and a peeling angle of 180°. It was peeled, and the adhesive force (mN/25 mm) to the silicon wafer was measured according to the 180° peel method according to JIS Z0237:2009. The results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

As can be seen from Tables 1 and 2, it was found that the adhesive sheets obtained in the examples exhibited sufficient adhesive force to the silicon wafer and exhibited excellent easy peelability. In particular, it was found that in the adhesive sheet obtained in the examples, the work could be easily peeled off even after 3 months from sticking.

The adhesive sheet of the present invention can be suitably used for work selection, inspection, rearrangement, storage, shipment, and return.

Claims (6)

An adhesive sheet for handling work, comprising a base material and an adhesive layer laminated on one side of the base material,
The adhesive layer is made of an inert energy ray-curable adhesive formed of an adhesive composition containing at least an acrylic polymer and a tackifier,
An adhesive sheet, characterized in that the tackifier is an alkylene glycol-modified rosin ester. According to paragraph 1,
An adhesive sheet, characterized in that the content of the alkylene glycol-modified rosin ester as the tackifier in the adhesive composition is 0.01 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the acrylic polymer. According to paragraph 1,
The adhesive composition contains a crosslinking agent,
An adhesive sheet, characterized in that the content of the crosslinking agent in the adhesive composition is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the acrylic polymer. According to paragraph 1,
An adhesive sheet, characterized in that the adhesive force to the mirror surface of a silicon wafer is 200 mN/25 mm or more and 3000 mN/25 mm or less. According to paragraph 1,
For a 10 mm When the silicon chip is removed from the adhesive sheet by sucking the silicon chip with a vacuum collet of 9.9 mm It is an adhesive sheet. A step of attaching one or more works to the surface of the adhesive sheet according to any one of claims 1 to 5 on the adhesive layer side;
A method of manufacturing a semiconductor device, comprising the step of separating at least one of the works from the adhesive sheet and placing it on a predetermined object.