JP2003105279A - Photosensitive double-sided self-adhesive tape/sheet and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive double-sided self-adhesive tape/sheet having a good adhesive basic property such as an initial adhesive power and a holding power, and capable of easily peeling from a material to be adhered by ultraviolet irradiation, and to provide a production method therefor. SOLUTION: The photosensitive double-sided self-adhesive tape/sheet is obtained by coating a photosensitive adhesive composed of an acrylic adhesive monomer having a photosensitive group, a thermal crosslinking agent and a photopolymerization initiator on both sides of a base material having a permeability to ultraviolet rays, wherein a weight average molecular weight of the acrylic adhesive monomer is 200,000-1,500,000, a content of the photosensitive group is 0.1-1.0 milliequiv/g, and a hydroxyl value is 10-100 mg KOH/g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-sensitive double-sided pressure-sensitive adhesive tape / sheet which can be easily peeled off from an adherend by irradiation of ultraviolet rays at any time after sticking, and a method for producing the same.

[0002]

2. Description of the Related Art Recently, in industries such as electric and electronic fields,
Along with the high performance, high functionality, and multi-product variety of products, there are increasing demands for adhesives and adhesives used for joining parts to have high heat resistance, high adhesiveness, and high reliability. In particular, from the viewpoint of improving workability efficiency and working environment, various components are often joined using a tape-shaped or sheet-shaped adhesive instead of the liquid adhesive.

In particular, it is strongly demanded that an adhesive tape for processing used when polishing or cutting various electronic parts also has a function of easily peeling from an adherend after use.

Conventionally, adhesives and waxes have been used for fixing during such processing, but (1) it takes a long time for the peeling work, (2) the parts are damaged when peeling, ( 3) Adhesive tapes and sheets are often used from the viewpoint that cleaning of parts is essential.

On the other hand, the adhesive tape has been widely used for various purposes such as packaging, packing, and curing. In recent years, from the viewpoint of environmental protection, resource saving, etc., the recycling of various daily necessities such as consumables has been sought after, and it is strongly demanded that adhesive tapes can be peeled without damaging the adherend when peeling. is there. Specifically, for adhesive tapes used for various surface protection and masking applications, labels and sealing applications, bundling applications, fixing of articles during transportation and movement, etc., at the same time as having excellent initial adhesive properties, It is required to have the property of easily peeling from the adherend at any time.

That is, it is desired to develop an adhesive tape having excellent basic adhesive properties as an adhesive tape such as initial adhesive strength and holding power, which can be easily peeled from an adherend when it is desired to peel it.

For example, it is attached to a semiconductor wafer, dicing (cutting into diced shapes), expanding (expanding from all sides), etc., if necessary, and then the cut semiconductor wafer chip is used for picking up. As an adhesive tape for semiconductor wafer processing, use a tape that has an adhesive layer that cures when exposed to ultraviolet light applied to a substrate that is transparent to ultraviolet light, and irradiates the adhesive layer with ultraviolet light after dicing. Then, the adhesive layer is subjected to a curing reaction to reduce the adhesive force to the semiconductor wafer,
A method of picking up a semiconductor wafer chip is known.

For example, in JP-A-60-196956 and JP-A-60-223139, trimethylolpropane triacrylate, pentaerythritol triacrylate, polyethylene glycol are used as the photopolymerizable monomer constituting the adhesive layer. It has been proposed to use an acrylic compound having at least two carbon-carbon double bonds having UV-polymerizability in the molecule, such as diacrylate and oligoester diacrylate.

Further, JP-A-62-153376 proposes to use a polyfunctional urethane acrylate oligomer having a molecular weight of about 3,000 to 10,000.

Further, in Japanese Patent Laid-Open No. 6-49420,
In order to prevent deterioration due to heat or light, the molecular weight is 15,000 to 5
There has been proposed a pressure-sensitive adhesive layer containing various polyfunctional urethane acrylate oligomers, a plasticizer, and a photopolymerization initiator as essential components.

[0011]

However, JP-A-60-
In the pressure-sensitive adhesive layer using the compounds described in 196956 and JP-A-60-223139, JP-A-10-1998
As described in JP-A-310748, since the viscosity of the compound is low, the viscosity of the entire pressure-sensitive adhesive layer is lowered, and the cohesive force becomes insufficient, and as a result, chipping (chip chipping) occurs during dicing. It also had the drawback that chips could easily scatter.

Further, because of the high polymerizability of the above compounds, the polymerization reaction proceeds due to heat and light applied during use, the adhesive force to the wafer is reduced, chips are scattered during dicing, and further, ultraviolet irradiation is performed. There is also a drawback that it becomes difficult to pick up the chip because the adhesive strength afterwards is not sufficiently reduced.

In the pressure-sensitive adhesive layer using a polyfunctional urethane acrylate oligomer having a molecular weight in the range described in JP-A-62-153376, the pressure-sensitive adhesive at the dicing point peels off to contaminate the chip, Since the cohesive force of the pressure-sensitive adhesive layer is insufficient, in this case as well, there were problems such as chipping during dicing and chip scattering.

Further, in the method described in JP-A-6-49420, when a plasticizer is used as an essential component, the adhesive properties before and after irradiation with ultraviolet rays may not be sufficiently exhibited depending on the type and blending amount of the plasticizer. There is a problem that the adhesive component remains on the wafer (adhesive remains), which is not preferable.

For example, if the adhesive remains on the semiconductor adhered surface,
Due to that, the reliability of the semiconductor element is lowered, which is not preferable in practical use. Therefore, there is a strong demand for the adhesive tape for semiconductor substrate processing that after the adhesive tape is peeled off after being irradiated with ultraviolet rays, no adhered matter such as an adhesive remains on the peeled surface.

An object of the present invention is to solve the problems of the above-mentioned conventional materials and techniques, to provide good basic adhesive properties such as initial adhesive force and holding force, and to remove after adhesion. An object of the present invention is to provide a light-sensitive adhesive tape / sheet that can be easily peeled off from an adherend and a method for manufacturing the same.

[0017]

In order to achieve the above object, the present invention has a structure as described in the claims.

That is, a light-sensitive adhesive obtained by applying a light-sensitive adhesive composed of an acrylic pressure-sensitive adhesive polymer having a photoactive functional group, a thermal crosslinking agent, and a photopolymerization initiator on both sides of the substrate. In the double-sided pressure-sensitive adhesive tape / sheet, the weight average molecular weight of the acrylic pressure-sensitive adhesive polymer is 200,000 to 1,500,000,
The content of the photoactive functional group is 0.1 to 1.0 meq /
g and the hydroxyl value is 10 to 100 mgKOH / g.

In this case, as the base material, a non-halogenated stretchable polymer film which is transparent to ultraviolet rays is used.

In this case, a non-halogen-based non-stretchable polymer film which is transparent to ultraviolet rays is used as the base material.

In the method for producing the light-sensitive double-sided pressure-sensitive adhesive tape / sheet, the light-sensitive pressure-sensitive adhesive is applied to both surfaces of the base material in a thickness of 5 to 50 μm to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive is formed. The pressure-sensitive adhesive layer is cured by heating and drying the agent layer.

[Detailed Description of the Invention] In order to achieve the above object, the present inventors have studied various materials and processes for producing a light-sensitive double-sided adhesive tape / sheet, and as a result, To
A double-sided adhesive tape / sheet prepared by applying a photosensitive adhesive consisting of an acrylic adhesive high molecular weight polymer having a photoactive functional group, a thermal cross-linking agent, and a photopolymerization initiator has an initial adhesive strength and holding power. Adhesive basic characteristics such as
It was confirmed that a light-sensitive double-sided pressure-sensitive adhesive tape / sheet that can be easily peeled off from an adherend by irradiation with light when desired to be peeled off.

By using such materials and processes, both of the light-sensitive surfaces which are excellent in initial adhesive properties and can be easily peeled off from the adherend without leaving an adhesive residue on the adherend by light irradiation. It was confirmed that it could be an adhesive tape / sheet.

In particular, the acrylic adhesive high molecular weight product having a photoactive functional group used in the present invention has a functional group which is crosslinked by a photoradical reaction in a polymer side chain or the like, and is peeled by irradiation with light. In addition, it was confirmed that the cohesive force of the pressure-sensitive adhesive increases due to curing shrinkage due to the photo-crosslinking reaction, the interface peels off, and the pressure-sensitive adhesive does not remain on the adherend when peeled from the adherend.

Hereinafter, the light-sensitive double-sided adhesive tape of the present invention
The sheet and the manufacturing method thereof will be described.

The acrylic pressure-sensitive adhesive polymer having a photoactive functional group used in the present invention is used for imparting easy peelability at the time of light irradiation peeling of the pressure-sensitive adhesive tape / sheet, and at the same time, has an initial pressure-sensitive adhesive property, It is also used to improve workability such as coating properties. The acrylic pressure-sensitive adhesive polymer having a photoactive functional group has a weight average molecular weight of 200,000 to 1,500,000 and a photoactive functional group content of 0.1.
Is about 1.0 meq / g and has a hydroxyl value of 10
It is preferably 100 mgKOH / g.

As a method for introducing the above-mentioned photoactive functional group into an acrylic adhesive high molecular weight substance, an isocyanate compound having a (meth) acryloyloxy group as a hydroxyl group in the side chain of the acrylic high molecular weight substance is usually used (for example, Two
-Methacryloyloxyethyl isocyanate, etc.). In this way, (meta)
An acrylic adhesive high molecular weight product having an active functional group such as an acryloyloxy group can be obtained. However, the introduction method is not particularly limited. The acrylic pressure-sensitive adhesive polymer having a photoactive functional group is usually used by dissolving it in a general-purpose organic solvent such as ethyl acetate or toluene, and applied on a substrate.

When the weight average molecular weight of the acrylic adhesive high molecular weight product having a photoactive functional group is less than 200,000, the initial adhesive properties are not sufficient, and when peeled off after irradiation with ultraviolet rays, it is considered as an adherend. Contamination such as residual adhesive may be observed on the resulting substrate, which is not preferable.

When the weight average molecular weight is more than 1,500,000, there is no particular problem in the characteristics of the adhesive tape,
It is not preferable because it is difficult to mass-produce the acrylic adhesive high molecular weight product having a photoactive functional group.

Further, when the content of the photoactive functional group of the acrylic adhesive high molecular weight product having the photoactive functional group is less than 0.1, it is not preferable because the photosensitivity to ultraviolet rays is insufficient. When the content of the photoactive functional group is larger than 1.0 meq / g, the characteristics of the adhesive tape
Although there is no particular problem, it is not preferable because it is difficult to mass-produce the acrylic polymer with good storage stability and in mass production.

If the hydroxyl value of the acrylic pressure-sensitive adhesive polymer having a photoactive functional group is less than 10 mgKOH / g, the reaction with the thermal crosslinking agent is not sufficient.
The initial tackiness is not sufficient, and the hydroxyl value is 10
Even when it is more than 0 mgKOH / g, it is difficult to sufficiently exhibit the initial tackiness, and in any case, it is not preferable in practice.

The main component of the acrylic adhesive high molecular weight compound having a photoactive functional group is usually a copolymer of a (meth) acrylic acid alkyl ester monomer and a polar group-containing monomer, for example, A copolymer of 2-ethylhexyl acrylate and acrylic acid, a copolymer of isooctyl acrylate and 2-hydroxyethyl methacrylate, acrylic acid 2
A terpolymer such as -ethylhexyl, acrylic acid, and 2-hydroxyethyl methacrylate is used, but the terpolymer is not particularly limited thereto.

Examples of the above-mentioned (meth) acrylic acid alkyl ester monomer include ethyl group, propyl group,
Usually, it has a carbon number of 20 represented by butyl group, pentyl group, hexyl group, 2-ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group and the like.
Examples thereof include esters of (meth) acrylic acid having the following alkyl groups. The above-mentioned (meth) acrylic acid alkyl ester is used alone or in combination of two or more kinds.

The above polar group-containing monomer includes acrylic acid, methacrylic acid, itaconic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl acrylate, acrylonitrile, methacrylonitrile. , N-vinyl-2-pyrrolidone and the like, and polymerizable unsaturated monomers having a polar group such as a carboxyl group, a hydroxyl group and an amino group in the molecule.

When the pressure-sensitive adhesive composed of the above-mentioned acrylic pressure-sensitive adhesive polymer having a photoactive functional group is coated on a substrate, the above-mentioned acrylic pressure-sensitive adhesive polymer having a photoactive functional group is treated with ethyl acetate, It is preferable to use it after dissolving it in an organic solvent such as toluene.

The photopolymerization initiator used in the present invention is a general photopolymerization initiator generally used for radical photopolymerization of vinyl group or (meth) acryloyloxy group, or used for curing an ultraviolet curable resin. Radical photopolymerization initiators can be used. For example, compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, trichloroacetophenone, benzophenone and benzyl can be used.

Further, the following photopolymerization initiators sold by Ciba Specialty Chemicals can also be used. For example, benzyl dimethyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure 651 manufactured by Ciba Specialty Chemicals), 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals). Irgacure 184), 2-hydroxy-2-methyl-1
-Phenylpropan-1-one (Darocur 1173 manufactured by Ciba Specialty Chemicals, Ltd.) and other α-hydroxyketone compounds, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1
(Ciba Specialty Chemicals Irgacure 369) and other α-aminoketone compounds, bis (2,
Bisacylphosphine oxide compounds such as 4,6-trimethylbenzoyl) phenylphosphine oxide (Irgacure 819 from Ciba Specialty Chemicals), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl A 1: 3 mixture of bisacylphosphine oxide such as phosphine oxide and Darocur 1173 (Irgacure 1700 from Ciba Specialty Chemicals), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine. 1: 1 mixture of bisacylphosphine oxide such as fin oxide and Irgacure 184 (Irgacure 1850 from Ciba Specialty Chemicals), benzoin ethyl ether,
Examples thereof include benzoin ether compounds such as benzoin isopropyl ether.

The photopolymerization initiator is not limited to those listed here, but may be diethanolamine or N-.
It may be used together with a photocuring accelerator such as methyl dimethylaminobenzoate.

These photopolymerization initiators are preferably used in a proportion of 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic tacky polymer having a photoactive functional group. If the amount used is less than 0.1 parts by weight, it is difficult to sufficiently complete the photo-curing reaction, and if the amount used is more than 5 parts by weight, the adhesive properties of the adhesive tape may deteriorate. However, there is a risk of contamination of the substrate, which is not preferable.

The thermal crosslinking agent used for the pressure-sensitive adhesive comprising the acrylic pressure-sensitive adhesive polymer having a photoactive functional group is generally an isocyanate compound-based crosslinking agent used as a crosslinking agent for acrylic pressure-sensitive adhesives. Epoxy compound-based cross-linking agents, aluminum chelate compound-based cross-linking agents and the like are used, but isocyanate compound-based cross-linking agents are particularly preferable.

For example, polyisocyanate cross-linking agents (trade name: L-45 etc.), epoxy compound cross-linking agents (trade name: E-AX etc.), aluminum chelate compound cross-linking agents (commodity) sold by Soken Chemical Industry Co., Ltd. (Name: M-5A, etc.) and the like can be used, but the invention is not limited to those listed here.

These thermal cross-linking agents are added to 100 parts by weight of the acrylic polymer having a photoactive functional group.
It is preferably used in a proportion of 0.1 to 5 parts by weight. If the amount used is less than 0.1 parts by weight or more than 5 parts by weight, sufficient adhesive properties cannot be obtained in any case, which is not preferable.

The pressure-sensitive adhesive solution of the present invention is in a liquid state, coated on a substrate such as a polyolefin film or a polyester film by a roll coater, a die coater or the like, heated and dried to form a thickness of 5 to 50 μm. Is preferred. The thickness of the base material is not particularly limited, but a thickness of 5 μm to 150 μm is usually used.

A silicone-based release agent is used for the release agent layer of the base material, but a non-silicone-based release agent can also be used from the viewpoint of stain resistance and the like. For example, a long-chain alkyl ester of polyvinyl alcohol (for example, On the other hand, examples include Pyrroyl 1010 manufactured by Sekiyu Yushi Kogyo Co., Ltd.), vinylcarbazole compounds, aminoalkyd resins and the like. These release agents are usually used by coating them on a substrate in a thickness of 0.1 to 3 μm.

When the substrate to be processed / cut is a relatively thick and brittle ceramic substrate or crystal substrate, the adhesive tape is not pulled in all directions when picking up the chip of the processed / cut substrate. A non-halogen-based non-stretchable polymer film (for example, a polyester film) which is less likely to generate dioxin or the like during burning is used as the base material of the adhesive tape.

When the substrate to be processed / cut is a relatively thin silicon wafer or glass substrate, the adhesive tape is stretched in all directions when picking up the cut chip, so that it has elasticity. Polymer films are used. In particular, in the present invention, a non-halogenated polyolefin-based stretchable polymer film (for example, polyethylene-based or polypropylene-based) which is less likely to generate dioxin during combustion is used.

The semiconductor substrate to which the present invention is applied includes
Examples include silicon wafers and gallium-arsenic substrates, examples of thin film substrates include alumina substrates, crystal substrates, and various printed wiring boards such as glass fiber reinforced epoxy substrates.

Usually, when the light-sensitive double-sided pressure-sensitive adhesive tape of the present invention is prepared, a toluene solution of the light-sensitive pressure-sensitive adhesive is used to coat a film base material with a comma coater or the like and heat-curing it. Thus, a light-sensitive double-sided adhesive tape is obtained.

In this case, the coating thickness of the photosensitive adhesive is preferably in the range of 5 to 50 μm.
When the thickness of the photosensitive adhesive is less than 5 μm, it is difficult to obtain stable adhesive properties, and
When the thickness of the photosensitive adhesive is larger than 50 μm, when the substrate is cut, a shift is likely to occur, and the substrate is likely to be chipped, which is not preferable.

The light-sensitive double-sided pressure-sensitive adhesive tape produced in this manner has excellent adhesiveness at the time of joining, can fix an adherend, and can be peeled off by irradiating with ultraviolet rays to give an adhesive force. Is reduced, and it can be easily peeled off from the substrate to be an adherend.

As the pedestal to which the light-sensitive double-sided adhesive tape is attached, a plate having transparency to ultraviolet rays such as glass, acrylic, polyester, polypropylene is used.

For UV irradiation, a usual UV irradiation light source can be used. For example, a high pressure mercury lamp, a metal halide lamp, a black light, a low pressure mercury lamp, etc. are used. Further, radiation such as electron beam or soft X-ray can be used instead of ultraviolet light.

As described above, the light-sensitive double-sided pressure-sensitive adhesive tape of the present invention has excellent initial pressure-sensitive adhesive properties for various semiconductor substrates and thin film substrates, and has excellent chipping resistance during dicing, and A light-sensitive double-sided adhesive tape with excellent storage stability.

Adhesive tapes for processing semiconductor substrates, thin film substrates, printed wiring boards and the like are used for dicing the substrates and washing with cold water (normally, water pressure: about 200).
kPa) has a large adhesive force that can fix the cut chips sufficiently, and a small adhesive force that can be easily peeled off when picking up the cut chips after UV irradiation and does not cause adhesive residue. Is required,
The light-sensitive double-sided pressure-sensitive adhesive tape of the present invention sufficiently satisfies the demand.

A pressure-sensitive adhesive composition which is reduced in adhesive strength by UV irradiation and can be peeled is usually a system in which a monomer or oligomer having ultraviolet-reactivity is added to an adhesive composition having no ultraviolet-reactivity. However, in the system in which the reactive monomer or the reactive oligomer is added, there is a risk of contamination of the cut chips, whereas in the composition of the present invention, the above-mentioned contamination is caused because the photosensitive high molecular weight component is the main component. There are no worries.

The light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention and the method for producing the same will be specifically described below. However,
The light-sensitive double-sided pressure-sensitive adhesive tape sheet of the present invention is not limited to the one produced by this method.

First, the acrylic adhesive polymer having the photoactive functional group, the thermal cross-linking agent, the photopolymerization initiator and the organic solvent are mixed in a predetermined amount and sufficiently stirred to obtain a uniform adhesive. Get a solution. At this time, the viscosity of the pressure-sensitive adhesive at 25 ° C. is preferably 1,000 to 10,000 cP for coating. The viscosity is adjusted according to the film thickness required for the adhesive tape / sheet and the coating method.

The pressure-sensitive adhesive solution thus prepared is coated on a sheet base material with a roll coater, a die coater or the like, and then dried by heating at 40 to 100 ° C. to give a light-sensitive double-sided adhesive tape having a thickness of 5 to 50 μm.・ A sheet is obtained.

The light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention is thus obtained, and is excellent when the light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention is attached to an adherend such as an electric / electronic component. It also exhibits initial adhesive properties and easy peelability after UV irradiation.

[0060]

EXAMPLES The light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention and the method for producing the same will be specifically described with reference to Examples. However, the light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention and the method for producing the same are not limited thereto. In addition, "parts" in the description of the examples represent parts by weight.

The methods for measuring various adhesive properties are shown below. (1) Adhesive force: 90 ° with respect to a stainless plate or a silicon wafer according to the method of JIS Z 0237-1991
Peel force was measured using a tensile tester. (Measurement condition: 23 ° C./65% RH, tape pressure bonding condition: use a metal roll of 2 kg.) (2) Tack: according to the method of JIS Z 0237, 2
The ball tack at an angle of 30 ° was measured at 3 ° C / 65% RH (J. DOW method).

Example 1 Weight average molecular weight of 800,000, active functional group content of 0.59 meq / g, hydroxyl value of 5
Polyisocyanate thermal cross-linking agent L-45 was added to 100 parts of an adhesive solution having a solid content of 30% by weight, which was prepared by dissolving an acrylic adhesive high molecular weight polymer having 6 mgKOH / g of 2-ethylhexyl acrylate as a main component in ethyl acetate. (Manufactured by Soken Chemical Co., Ltd.) 0.15 parts and photopolymerization initiator Irgacure 651
(Ciba Specialty Chemicals Co., Ltd.) 0.2 parts was added and mixed uniformly to obtain a photosensitive adhesive coating liquid.

This photosensitive adhesive coating solution is a corona-treated stretchable polyolefin film (hereinafter abbreviated as PE / PP / PE-based polyolefin film) having a three-layer structure of polyethylene / polypropylene / polyethylene having a thickness of 90 μm. ) Apply a comma coater on the base material and apply 100
It was dried by heating at ° C / 5 minutes to obtain a light-sensitive adhesive tape having an adhesive layer with a thickness of 10 µm. Further, the opposite surface of the PE / PP / PE-based polyolefin film substrate was similarly coated to give a double-sided adhesive tape. This photosensitive double-sided pressure-sensitive adhesive tape was left at room temperature for 1 week to age the pressure-sensitive adhesive layer.

The initial adhesive force of this light-sensitive double-sided adhesive tape was 3.1 N / 10 mm (800 gf / 25 mm, against stainless steel substrate), 2.9 N / 10 mm (750 gf / 2).
5 mm, silicon wafer), and the ball tack was 4.

Ultraviolet rays (ultraviolet ray intensity at 365 nm:
The adhesive force after irradiating (75 mW / cm ² ) for 4 seconds is
0.2 N / 10 mm (50 gf / 25 mm) (against a stainless steel substrate and a silicon wafer), and the ball tack was less than 3. As a result, the light-sensitive double-sided pressure-sensitive adhesive tape of the present invention has excellent adhesive force to the adherend in the normal state, the adhesive force is significantly reduced after ultraviolet irradiation, and can be easily peeled from the adherend. It was confirmed.

Further, a silicon substrate is diced using the above-mentioned light-sensitive double-sided adhesive tape, and then a silicon chip is picked up, and the back surface of the chip (portion where the adhesive is in contact) is digital microscope VH-6200.
As a result of observation with (manufactured by Keyence Corporation), no adhesive residue was observed on the back surface of the chip, and it was confirmed that the chip had excellent heat peelability.

As described above, the light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention has both good initial pressure-sensitive adhesiveness and easy peelability after irradiation with ultraviolet rays.
It was confirmed that it also functions as a seat.

Example 2 A weight average molecular weight of 800,000,
To 100 parts of a 30% by weight ethyl acetate solution of an acrylic adhesive high molecular weight polymer having an active functional group content of 0.40 meq / g and a hydroxyl value of 80 mgKOH / g as a main component of 2-ethylhexyl acrylate. , Polyisocyanate thermal cross-linking agent L-45 (manufactured by Soken Chemical Industry Co., Ltd.) 0.2 part and photopolymerization initiator Irgacure 819 (Ciba Specialty.
Chemicals Co., Ltd.) 0.3 part was added and mixed well,
A pressure-sensitive adhesive solution having a viscosity at 3000C of 3,000 cP was obtained.

This photosensitive adhesive coating liquid was applied on a 125 μm thick corona-treated non-stretchable polyester base material by comma coating and dried at 100 ° C. for 5 minutes to form an adhesive layer having a thickness of 20 μm. A photosensitive adhesive tape of was obtained. Further, it was similarly coated on the opposite surface of the above-mentioned corona-treated non-stretchable polyester substrate. The light-sensitive double-sided pressure-sensitive adhesive tape thus obtained was left at room temperature for 1 week to age the pressure-sensitive adhesive layer.

The initial adhesive force of this light-sensitive double-sided adhesive tape is 3.9 N / 10 mm (1000 gf / 25 mm, against stainless steel substrate) 3.7 N / 10 mm (950 gf / 950 gf /
25mm, silicon wafer), ball tack is 4
Met.

A black light was applied to the light-sensitive double-sided pressure-sensitive adhesive tape to emit ultraviolet light (ultraviolet intensity at 365 nm:
3 mW / cm ² ) after 30 seconds of irradiation, the adhesive force is
0.16 N / 10 mm (40 gf / 25 mm) (against stainless steel substrate and silicon wafer), and the ball tack was less than 3. As a result, the light-sensitive double-sided pressure-sensitive adhesive tape of the present invention has excellent adhesive force to the adherend in the normal state, the adhesive force is significantly reduced after ultraviolet irradiation, and can be easily peeled from the adherend. It was confirmed.

A 2 mm-thick crystal substrate was diced using the above-mentioned light-sensitive double-sided adhesive tape, and then a crystal chip was picked up, and the back surface of the chip (the part where the adhesive was in contact) was digital microscope VH. -620
When observed with 0 (manufactured by KEYENCE CORPORATION), no adhesive residue was observed on the back surface of the chip, and it was confirmed that excellent heat peelability was exhibited.

As described above, the light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention has both good initial pressure-sensitive adhesiveness and easy peelability after irradiation with ultraviolet rays.
It was confirmed that it also functions as a seat.

[Examples 3 to 10] In the same manner as in Examples 1 and 2, light-sensitive double-sided pressure-sensitive adhesive tapes and sheets were produced under the composition and production conditions shown in Table 1. In Table 1, 100 parts by weight of the acrylic pressure-sensitive adhesive high molecular weight substance having a photoactive functional group is shown only by the solid content containing no solvent. Further, before measuring the adhesive strength and the like, this light-sensitive double-sided adhesive tape / sheet was left to stand at room temperature for 1 week to be aged.

Further, the ultraviolet irradiation dose was high pressure water.
300mJ / cm using a silver lamp ^TwoIrradiate the ultraviolet rays of
It was

Table 2 shows the results of observing the initial adhesive strength of these light-sensitive double-sided adhesive tapes / sheets to a stainless steel plate and a silicon wafer, the adhesive strength after ultraviolet irradiation, and the adhesive residue on an adherend. As can be seen from the table, it was confirmed that all of the pressure-sensitive adhesive tapes exhibited good initial pressure-sensitive adhesive properties and easy peelability after irradiation with ultraviolet rays, and also had a function as a light-sensitive double-sided pressure-sensitive adhesive tape.

[0077]

[Table 1]

[0078]

[Table 2]

As described above, the light-sensitive double-sided pressure-sensitive adhesive tape / sheet of the present invention comprises an acrylic pressure-sensitive adhesive polymer having a photoactive functional group on both sides of a substrate, a heat-crosslinking agent, and In the light-sensitive adhesive tape / sheet obtained by applying a light-sensitive adhesive comprising a photopolymerization initiator, the acrylic adhesive high molecular weight polymer has a weight average molecular weight of 200,000 to 150.
The content of the photoactive functional group is 0.1 to 1.0 meq / g, and the hydroxyl value is 10 to 100 mgKOH / g.
Therefore, the above light-sensitive double-sided adhesive tape / sheet is
It has good basic adhesive properties such as adhesive strength and holding power, and can be easily peeled off from the adherend after ultraviolet irradiation.

In this case, since the base material is a non-halogenated stretchable polymer film having transparency to ultraviolet rays, when the substrate to be processed / cut is a relatively thin silicon wafer or glass substrate, When picking up the chip of the cut substrate, the adhesive tape can be pulled in all directions, and there is little concern that dioxin or the like will be generated during combustion, which is environmentally safe.

Further, in this case, since the base material is a non-halogen-based non-stretchable polymer film having transparency to ultraviolet rays, the substrate to be processed / cut is relatively thick, and is made of a brittle ceramic substrate or quartz plate. In this case, it is possible to pick up the processed / cut substrate chip without pulling the adhesive tape in all directions, and there is little concern that dioxin or the like will be generated during combustion, which is environmentally safe.

Further, in the method for producing the light-sensitive double-sided pressure-sensitive adhesive tape / sheet, the light-sensitive pressure-sensitive adhesive is applied to both surfaces of the substrate to a thickness of 5 to 50 μm to form a pressure-sensitive adhesive layer, which is dried by heating. To cure the pressure-sensitive adhesive layer,
A stable adhesive property can be obtained, and when the substrate is cut, a shift is unlikely to occur and the substrate is unlikely to be chipped.

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Claims (4)

[Claims] 1. A light-sensitive adhesive obtained by applying a light-sensitive adhesive consisting of an acrylic adhesive polymer having a photoactive functional group, a thermal cross-linking agent and a photopolymerization initiator on both sides of a substrate. In the double-sided pressure-sensitive adhesive tape / sheet, the acrylic pressure-sensitive adhesive polymer has a weight average molecular weight of 200,000 to 1,500,000, and the content of the photoactive functional group is 0.1 to 1.0 meq / g. Further, a photosensitive double-sided pressure-sensitive adhesive tape / sheet having a hydroxyl value of 10 to 100 mgKOH / g. 2. The light-sensitive double-sided pressure-sensitive adhesive tape sheet according to claim 1, wherein the base material is a non-halogen stretchable polymer film having transparency to ultraviolet rays. 3. The light-sensitive double-sided pressure-sensitive adhesive tape sheet according to claim 1, wherein the base material is a non-halogen-based non-stretchable polymer film having transparency to ultraviolet rays. 4. A pressure-sensitive adhesive layer according to claim 1, which is applied to the substrate to a thickness of 5 to 50 .mu.m to form a pressure-sensitive adhesive layer, which is then dried by heating to cure the pressure-sensitive adhesive layer. A method for producing a light-sensitive double-sided pressure-sensitive adhesive tape / sheet, comprising: