JP2014019790A - Adhesive composition, adhesive tape, and wafer processing method - Google Patents

Abstract

An adhesive having an initial adhesive force necessary and sufficient for fixing an adherend and capable of being easily peeled off without being left behind even after a high temperature processing process of 200 ° C. or higher. An adhesive composition, an adhesive tape using the adhesive composition, and a wafer processing method using the adhesive composition are provided.
A pressure-sensitive adhesive composition containing a silicone pressure-sensitive adhesive and fumed silica having an average particle size of 0.05 to 3 μm.
[Selection figure] None

Description

The present invention has an initial adhesive force necessary and sufficient for fixing an adherend, and can be easily peeled off without being left behind even after a high temperature processing process of 200 ° C. or higher. The present invention relates to an adhesive composition, an adhesive tape using the adhesive composition, and a wafer processing method using the adhesive composition.

In the manufacture of semiconductors, a semiconductor processing tape is applied to facilitate handling of the semiconductor during processing and prevent damage. For example, when a thick film wafer cut from a high-purity silicon single crystal or the like is ground to a predetermined thickness to form a thin film wafer, a double-sided adhesive tape is used to bond and reinforce the thick film wafer to a support plate. Used. An adhesive tape called a dicing tape is also used when dicing a thin film wafer ground to a predetermined thickness into individual IC chips.

The tape for semiconductor processing is required to have high adhesiveness capable of firmly fixing the semiconductor during the processing step and to be able to be peeled off after the step without damaging the semiconductor. On the other hand, Patent Document 1 discloses a pressure-sensitive adhesive tape using a photo-curing pressure-sensitive adhesive that is cured by irradiating light such as ultraviolet rays to reduce adhesive strength. Such an adhesive tape can reliably fix the semiconductor during the processing step and can be easily peeled off by irradiating with ultraviolet rays or the like.
Even if it is an adhesive tape using such a photocurable adhesive, when it is used at the time of processing of a semiconductor having a heating process, even if it is irradiated with ultraviolet rays, the adhesive force is not sufficiently lowered and cannot be peeled off. There was a problem that there was something. This is considered to be because the adhesive strength of the pressure-sensitive adhesive is increased by heating.

In recent years, an increasing number of semiconductor processing requires a high-temperature processing process of 200 ° C. or higher, such as a CVD process or a solder reflow process. After passing through such a high temperature processing process, even if it is the photocurable adhesive described in Patent Document 1, the adhesive is burned on the adherend, making it difficult to peel off, and after peeling The adhesive remains on the body. Such a problem of adhesive residue is particularly remarkable when unevenness such as a circuit is formed on the adherend surface.

JP-A-5-32946

The present invention has an initial adhesive force necessary and sufficient for fixing an adherend, and can be easily peeled off without being left behind even after a high temperature processing process of 200 ° C. or higher. It is an object of the present invention to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition, and a wafer processing method using the pressure-sensitive adhesive composition.

The present invention is a pressure-sensitive adhesive composition containing a silicone pressure-sensitive adhesive and fumed silica having an average particle size of 0.05 to 3 μm.
The present invention is described in detail below.

The inventor examined the cause of the adhesive remaining on the adherend when peeling was performed after a high temperature processing process of 200 ° C. or higher. As a result, it was found that the cause of the adhesive residue is the (meth) acrylic adhesive compounded as an adhesive component. The (meth) acrylic pressure-sensitive adhesive has high adhesiveness and can be imparted with various properties by selecting a monomer component as a raw material, so that it is particularly suitably used as a pressure-sensitive adhesive for semiconductor processing. However, (meth) acrylic pressure-sensitive adhesive, particularly when applied to a semiconductor with an uneven surface such as a circuit formed on the adherend surface and subjected to a high-temperature processing process of 200 ° C. or higher, increases the adhesive force. , Detachment from the adherend becomes difficult. Even when a photo-curing (meth) acrylic pressure-sensitive adhesive as described in Patent Document 1 is used, it is difficult to peel off without leaving adhesive residue. This is presumably because the (meth) acrylic pressure-sensitive adhesive follows the unevenness of the adherend surface and increases the adhesion by increasing the temperature.

This inventor examined using a silicone adhesive instead of the conventional (meth) acrylic adhesive. Silicone pressure-sensitive adhesives have excellent heat resistance and little increase in adhesion even when heated to high temperatures, so they can be easily peeled off without leaving any adhesive even when subjected to a high-temperature processing process at 200 ° C or higher. It was done. However, when a silicone pressure-sensitive adhesive is used, there is a problem that the adhesive strength at a high temperature is reduced, and often peels off from the adherend during a high-temperature processing process of 200 ° C. or higher.
As a result of further intensive studies, the present inventor, by blending fumed silica having a specific average particle diameter with a silicone adhesive, has high heat resistance that does not peel off even at a high temperature processing process of 200 ° C. or higher, and adhesive residue. The present invention has been completed by finding that it is possible to achieve both releasability that can be easily peeled off without being carried out.

The pressure-sensitive adhesive composition of the present invention contains a silicone pressure-sensitive adhesive.
Silicone pressure-sensitive adhesives have relatively low adhesive strength, and even when subjected to a high-temperature processing process of 200 ° C. or higher, there is almost no increase in adhesive strength. it can. On the other hand, the necessary and sufficient adhesive force can be maintained even during a high temperature processing process of 200 ° C. or higher by using a specific fumed silica described later.
In the present specification, the silicone pressure-sensitive adhesive means a pressure-sensitive adhesive containing as a main component a polymer having a siloxane bond (Si—O—Si bond) in the main chain or side chain.

Among the silicone pressure-sensitive adhesives, a pressure-sensitive adhesive containing a polymer having a siloxane bond in the main chain as a main component has a particularly low initial adhesive force, and even when a high-temperature processing process of 200 ° C. or higher is performed, the adhesion force is increased. Since there is almost no peeling after the end of the process.
Examples of the polymer having a siloxane bond in the main chain include silicone oil, silicone rubber, and silicone adhesive.

Examples of commercially available silicone pressure-sensitive adhesives mainly composed of a polymer having a siloxane bond in the main chain include X-40-3229, X-40-3270, X-40-3240, and KR3700 (all of which are Shin-Etsu Chemical Industry Co., Ltd.).

Examples of the polymer having a siloxane bond in the side chain among the silicone pressure-sensitive adhesive include, for example, a copolymer of (meth) acrylic monomer and silicone (meth) acrylate (hereinafter referred to as “(meth) acrylic-silicone copolymer”). Also referred to as "union"). The (meth) acryl-silicone copolymer can impart high adhesiveness or photocurability with (meth) acryl, together with high releasability due to the silicone component. In particular, when a (meth) acryl-silicone copolymer having photocurability is used, a relatively high initial adhesive strength can be secured, while the adhesive strength can be reduced by irradiating light during peeling. Due to the synergistic effect with the silicone component of the chain, it is possible to perform peeling without leaving any adhesive residue.

The photo-curing (meth) acryl-silicone copolymer is, for example, a (meth) acrylic polymer having a silicone component and a functional group in the molecule (hereinafter referred to as silicone component / functional group-containing (meth) acrylic). Polymer) is synthesized in advance and obtained by reacting with a compound having a functional group that reacts with the above functional group in the molecule and a radical polymerizable unsaturated bond (hereinafter referred to as a functional group-containing unsaturated compound). Can do.

The silicone component / functional group-containing (meth) acrylic polymer is an adhesive polymer at room temperature, as in the case of a general (meth) acrylic polymer, and the alkyl group usually has 2 to 18 carbon atoms. Other modifying monomers which can be copolymerized with a silicone compound having a functional group-containing monomer and a (meth) acrylic group as a main monomer, the alkyl acrylate and / or methacrylic acid alkyl ester in Can be obtained by copolymerizing with a conventional method. The weight average molecular weight of the silicone component / functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.

Examples of the functional group-containing monomer include a carboxyl group-containing monomer such as acrylic acid and methacrylic acid; a hydroxyl group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate; and an epoxy group containing glycidyl acrylate and glycidyl methacrylate. Monomers; Isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate; and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.

Examples of the silicone compound having a (meth) acryl group include X-22-164, X-22-164AS, X-22-164A, X-22-164B, and X-22-164C manufactured by Shin-Etsu Chemical Co., Ltd. , A silicone compound having methacrylic groups at both ends such as X-22-164E, and a methacrylic group at one end such as X-22-174DX, X-22-2426, X-22-2475 manufactured by Shin-Etsu Chemical Co., Ltd. Silicone compounds having acrylic groups such as EBECRYL350 and EBECRYL1360 manufactured by Daicel Cytec, silicone compounds having acrylic groups such as AC-SQ TA-100 and AC-SQ SI-20 manufactured by Toagosei Co., Ltd. MAC-SQ TM-100, MAC-SQ SI-20, MA manufactured by Toagosei Co., Ltd. Silicone compounds having a methacryl group such -SQ HDM like.

Examples of other modifying monomers that can be copolymerized include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

The functional group-containing unsaturated compound to be reacted with the silicone component / functional group-containing (meth) acrylic polymer is the same as the functional group-containing monomer described above according to the functional group of the functional group-containing (meth) acrylic polymer. Things can be used. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used, and when the functional group is an amino group, an epoxy group-containing monomer is used.

The (meth) acryl-silicone copolymer having photocurability may be used in combination with a polyfunctional oligomer or monomer.
The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5, so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by heating or light irradiation. 000 or less and the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20. Examples of such more preferable polyfunctional oligomers or monomers include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate. Or the above-mentioned methacrylates etc. are mentioned. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and methacrylates similar to those described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

When the (meth) acryl-silicone copolymer having photocurability is used as the pressure-sensitive adhesive component, the pressure-sensitive adhesive composition of the present invention preferably contains a photopolymerization initiator.
Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such a photopolymerization initiator include acetophenone derivative compounds such as methoxyacetophenone. Benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether; ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal; phosphine oxide derivative compounds; bis (η5-cyclopentadienyl) titanocene derivative compounds, benzophenone, Michler's ketone Chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenyl pro Examples thereof include photo radical polymerization initiators such as bread. These photoinitiators may be used independently and 2 or more types may be used together.

When the photo-curing (meth) acryl-silicone copolymer is used as the pressure-sensitive adhesive component, the pressure-sensitive adhesive composition of the present invention further comprises the photo-curing (meth) acryl-silicone copolymer and It is preferable to contain a silicone compound having a crosslinkable functional group (hereinafter also simply referred to as “silicone compound A”).
Since the silicone compound is excellent in heat resistance, the adhesive is prevented from being burnt even after a high temperature processing process of 200 ° C. or higher, and at the time of peeling, it bleeds out to the adherend interface to facilitate peeling. Since the silicone compound has a functional group capable of cross-linking with the pressure-sensitive adhesive component, it is incorporated into the pressure-sensitive adhesive component by chemically reacting with the pressure-sensitive adhesive component by light irradiation at the time of peeling. The compound will not adhere and contaminate. In addition, when one of the adherends is a support plate made of a glass plate, by adding a silicone compound having a functional group capable of crosslinking with the above-mentioned pressure-sensitive adhesive component, the affinity for the support plate is improved. The effect of preventing adhesive residue on the skin is also exhibited.

The silicone skeleton of the silicone compound A is not particularly limited, and may be either D-form or DT-form.
The silicone compound A preferably has the functional group at the side chain or terminal of the silicone skeleton.
In particular, the use of a silicone compound having a D-form silicone skeleton and having a functional group capable of crosslinking with the above-mentioned pressure-sensitive adhesive component at the end achieves both high initial adhesive strength and peeling strength after a high-temperature processing process. It is preferable because it is easy.

As the functional group of the silicone compound A, an appropriate one is selected and used according to the pressure-sensitive adhesive component. For example, when the pressure-sensitive adhesive component is a photocurable pressure-sensitive adhesive mainly composed of a (meth) acrylic acid alkyl ester-based polymerizable polymer having a radical polymerizable unsaturated bond in the molecule, (meth) A functional group capable of crosslinking with an acrylic group is selected.
The functional group capable of crosslinking with the (meth) acryl group is a functional group having an unsaturated double bond, and specific examples include a vinyl group, a (meth) acryl group, an allyl group, and a maleimide group. .

The functional group equivalent of the silicone compound A is not particularly limited, but the preferred lower limit is 1, and the preferred upper limit is 20. When the functional group equivalent is less than 1, the silicone compound A is not sufficiently taken into the pressure-sensitive adhesive component when the resulting pressure-sensitive adhesive composition is cured, and the adherend is contaminated or exhibits sufficient peelability. If it exceeds 20, sufficient adhesive strength may not be obtained. A more preferred upper limit of the functional group equivalent is 10, a more preferred lower limit is 2, and a more preferred upper limit is 6.

The molecular weight of the silicone compound A is not particularly limited, but a preferred lower limit is 300 and a preferred upper limit is 50000. If the molecular weight is less than 300, the resulting pressure-sensitive adhesive composition may have insufficient heat resistance, and if it exceeds 50,000, mixing with the pressure-sensitive adhesive component may be difficult. The more preferable lower limit of the molecular weight is 400, the more preferable upper limit is 10,000, the still more preferable lower limit is 500, and the more preferable upper limit is 5000.

The method of synthesizing the silicone compound A is not particularly limited. For example, by reacting a silicone resin having a SiH group and a vinyl compound having a functional group capable of crosslinking with the pressure-sensitive adhesive component, by a hydrosilylation reaction, Examples thereof include a method of introducing a functional group capable of crosslinking with the pressure-sensitive adhesive component into the silicone resin, and a method of causing a condensation reaction between the siloxane compound and a siloxane compound having a functional group capable of crosslinking with the pressure-sensitive adhesive component.

Examples of commercially available silicone compounds A include X-22-164, X-22-164AS, X-22-164A, X-22-164B, and X-22-164C manufactured by Shin-Etsu Chemical Co., Ltd. , A silicone compound having methacrylic groups at both ends such as X-22-164E, and a methacrylic group at one end such as X-22-174DX, X-22-2426, X-22-2475 manufactured by Shin-Etsu Chemical Co., Ltd. Silicone compounds having acrylic groups such as EBECRYL350 and EBECRYL1360 manufactured by Daicel Cytec, silicone compounds having acrylic groups such as AC-SQ TA-100 and AC-SQ SI-20 manufactured by Toagosei Co., Ltd. MAC-SQ TM-100, MAC-SQ SI-20, MAC-S manufactured by Toagosei Co., Ltd. Silicone compounds having a methacryl group such as HDM and the like.

Among these, the silicone compound A has particularly high heat resistance and high polarity, so that bleeding out from the pressure-sensitive adhesive composition is easy. Therefore, the following general formula (I), general formula (II), and general formula A silicone compound represented by (III) having a (meth) acryl group in the siloxane skeleton is preferred.

In the formula, X and Y represent an integer of 0 to 1200 (except when X and Y are both 0), and R represents a functional group having an unsaturated double bond.

Of the silicone compounds having a (meth) acryl group in the siloxane skeleton represented by the above general formula (I), general formula (II), or general formula (III), commercially available products are, for example, manufactured by Daicel Cytec Co., Ltd. EBECRYL350, EBECRYL1360 (both of which R is an acrylic group) and the like.

The content of the silicone compound A is preferably 0.5 parts by weight with respect to 100 parts by weight of the (meth) acryl-silicone copolymer having photocurability, and 40 parts by weight. When the content of the silicone compound A is less than 0.5 parts by weight, the adhesive strength may not be sufficiently reduced even when irradiated with light, and may not be peeled off from the adherend. May cause body contamination. The more preferable lower limit of the content of the silicone compound A is 1 part by weight, and the more preferable upper limit is 30 parts by weight.

The pressure-sensitive adhesive composition of the present invention contains fumed silica.
By blending fumed silica, the heat resistance of the pressure-sensitive adhesive composition of the present invention is remarkably improved, and the adherend is not peeled even during a high-temperature processing process at 200 ° C. or higher.

The lower limit of the average particle diameter of the fumed silica is 0.05 μm, and the upper limit is 3 μm. When the average particle size of the fumed silica is within this range, even when subjected to a high-temperature processing process of 200 ° C. or higher, high heat resistance that does not cause floating and the like after undergoing a high-temperature processing process of 200 ° C. or higher Even when peeled, it can exhibit high non-glue residue that does not leave glue. The preferable lower limit of the average particle diameter of the fumed silica is 0.06 μm, the preferable upper limit is 2 μm, the more preferable lower limit is 0.07 μm, and the more preferable upper limit is 1 μm.
In addition, in this specification, the average particle diameter of fumed silica is determined by using any of the laser scattering / diffraction method or the dynamic light scattering method, methyl ethyl ketone, methyl ethyl ketone / toluene (60:40) solution before blending, or the like. The particle diameter of fumed silica dispersed in the medium is measured.

As for the compounding quantity of the said fumed silica, the preferable minimum with respect to 100 weight part of said silicone adhesives is 10 weight part, and a preferable upper limit is 40 weight part. When the blended amount of the fumed silica is within this range, high heat resistance that does not cause floating even when subjected to a high temperature processing process of 200 ° C. or higher, and peeling after undergoing a high temperature processing process of 200 ° C. or higher In particular, a high non-glue remaining property that does not leave a glue residue can be exhibited. The more preferred lower limit of the amount of fumed silica blended is 15 parts by weight, the more preferred upper limit is 38 parts by weight, the still more preferred lower limit is 20 parts by weight, and the still more preferred upper limit is 35 parts by weight.

The pressure-sensitive adhesive composition of the present invention preferably contains a urethane acrylate oligomer.
By blending the urethane acrylate oligomer, the tensile strength of the pressure-sensitive adhesive composition of the present invention is remarkably improved. For this reason, even after passing through the high temperature processing process of 200 degreeC or more, it can peel without the adhesive being fractured | ruptured by the stress at the time of peeling, and an adhesive residue remaining.
The urethane acrylate oligomer means an oligomer having a weight average molecular weight of 1,000 to 100,000 in terms of polystyrene and having a plurality of (meth) acrylate groups in one molecule.
In addition, the weight average molecular weight by polystyrene conversion can be obtained by performing GPC measurement using column LF-804 (made by Showa Denko KK) as a column, for example.

Examples of the urethane acrylate oligomer include UN5500, UN1225, UN9200A manufactured by Negami Kogyo Co., Ltd., UF8001G manufactured by Kyoeisha Chemical Co., U200PA, UA4200 manufactured by Shin-Nakamura Chemical Co., Ltd., and the like.

As for the compounding quantity of the said urethane acrylate oligomer, the preferable minimum with respect to 100 weight part of said silicone adhesives is 1 weight part, and a preferable upper limit is 50 weight part. When the blended amount of the urethane acrylate oligomer is within this range, high heat resistance that does not cause floating even when subjected to a high temperature processing process of 200 ° C. or higher, and peeling after passing through a high temperature processing process of 200 ° C. or higher In particular, a high non-glue remaining property that does not leave a glue residue can be exhibited. The more preferable lower limit of the blending amount of the urethane acrylate oligomer is 5 parts by weight, the more preferable upper limit is 40 parts by weight, the still more preferable lower limit is 10 parts by weight, and the still more preferable upper limit is 30 parts by weight.

The pressure-sensitive adhesive composition of the present invention may appropriately contain various polyfunctional compounds that are blended with general pressure-sensitive adhesives such as isocyanate compounds, melamine compounds, and epoxy compounds for the purpose of adjusting the cohesive force. Moreover, well-known additives, such as an antistatic agent, a plasticizer, resin, surfactant, and wax, can also be added. Furthermore, you may mix | blend a heat stabilizer and antioxidant in order to improve stability of an adhesive.

The pressure-sensitive adhesive composition of the present invention may further contain a gas generating agent that generates gas when irradiated with light. When light is applied to the pressure-sensitive adhesive composition containing such a gas generating agent, the photocurable pressure-sensitive adhesive component is cross-linked and cured to increase the elastic modulus of the entire pressure-sensitive adhesive, and in such a hard pressure-sensitive adhesive. The generated gas is released from the pressure-sensitive adhesive to the bonding interface and peels at least a part of the bonding surface, so that peeling can be facilitated.
Although the said gas generating agent is not specifically limited, For example, an azide compound, an azo compound, a ketoprofen, a tetrazole compound etc. are mentioned. Of these, salts of tetrazole compounds having excellent heat resistance are preferred.

The pressure-sensitive adhesive composition of the present invention has an initial pressure-sensitive adhesive force necessary for fixing an adherend, but can be easily peeled off. In particular, even after a high-temperature processing process of 200 ° C. or higher, it can be peeled without any adhesive residue. Therefore, the pressure-sensitive adhesive composition of the present invention is a high-temperature treatment at 200 ° C. or higher, such as fixing a wafer to a support plate in a TSV manufacturing process, or temporarily fixing a wafer or chip to a support plate when passing through a reflow furnace. It can use suitably for the use which performs.

The pressure-sensitive adhesive composition of the present invention can be used for various adhesive products.
The adhesive product is, for example, an adhesive, a pressure-sensitive adhesive, a paint, a coating agent, a sealing agent or the like using the pressure-sensitive adhesive composition of the present invention as a binder resin, or the pressure-sensitive adhesive composition of the present invention as a pressure-sensitive adhesive. Examples thereof include adhesive tapes such as single-sided adhesive tape, double-sided adhesive tape, and non-support tape (self-supporting tape). Among them, a support plate fixing tape at high temperature processing, a fixing tape for both high temperature processing and back grinding, a fixing tape for high temperature processing and dicing, and used for further high temperature processing of individual semiconductor chips. It is suitable for a semiconductor chip temporary fixing tape or the like.

An adhesive tape having an adhesive layer made of the adhesive composition of the present invention on at least one surface of the substrate is also one aspect of the present invention.
The base material is, for example, a sheet made of a transparent resin such as acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, urethane, polyimide, or a network structure. And a sheet having a hole and the like.

The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, a conventionally known method such as coating the above-mentioned pressure-sensitive adhesive or the like on a base material using a doctor knife, a spin coater or the like can be used. .

The pressure-sensitive adhesive composition of the present invention is an adhesive for fixing a wafer to a support plate in order to facilitate handling of the wafer and prevent damage during processing of a wafer including a high-temperature processing process of 200 ° C. or higher. Suitable as an agent.
Although the high temperature processing process should just be 200 degreeC or more, the minimum temperature of a preferable high temperature processing process is 220 degreeC, and the more preferable minimum temperature is 230 degreeC. The upper limit of the high temperature processing process is not particularly limited, but is 300 ° C. or less, the preferable upper limit temperature is 280 ° C., and the more preferable upper limit temperature is 260 ° C.

A support plate fixing step of fixing the wafer to the support plate via the pressure-sensitive adhesive composition of the present invention, a wafer processing step of subjecting the surface of the wafer fixed to the support plate to a treatment involving heating at 200 ° C. A wafer processing method is also one aspect of the present invention, which includes a support plate peeling step of irradiating the processed wafer with light, curing the pressure-sensitive adhesive composition, and peeling the support plate from the wafer.

The said support plate is not specifically limited, For example, a glass plate, a quartz glass plate, a stainless steel plate etc. are mentioned.
A process involving heating at 200 ° C. or higher on the surface of the wafer fixed to the support plate is not particularly limited, and examples thereof include chemical vapor deposition (CVD), reflow, and reactive ion etching (RIE).

According to the present invention, it has an initial adhesive force necessary and sufficient for fixing an adherend, and can be easily peeled off without being left behind even after a high temperature processing process of 200 ° C. or higher. It is possible to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition, and a wafer processing method using the pressure-sensitive adhesive composition.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Examples 1-7, Comparative Examples 1-4)
According to the composition shown in Table 1, X-40-3229, X-40-3270, X-40-3240, KR3700 (all manufactured by Shin-Etsu Chemical Co., Ltd.) as silicone resins, and UN5500 (Negami) as urethane acrylate oligomers Kogyo Co., Ltd.) was blended to obtain a resin mixture. Methyl ethyl ketone and fumed silica (manufactured by Tokuyama, MT10) were blended into the obtained resin mixture, and fumed silica was dispersed to the average particle size shown in Table 1 using a homogenizer to prepare an adhesive composition.

A doctor knife so that the ethyl acetate solution of the obtained pressure-sensitive adhesive composition has a dry film thickness of 30 μm on the corona-treated surface of a transparent polyethylene naphthalate film having a thickness of 50 μm that has been corona-treated on one side. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Evaluation)
About the adhesive composition and adhesive tape obtained by the Example and the comparative example, it evaluated by the following method.
The results are shown in Table 1.

(1) Evaluation of initial adhesive force before heat treatment of adhesive tape An adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer (circuit wafer) having a thickness of 700 μm on which a circuit having a diameter of 20 cm and a step of about 5 μm was formed. . A glass plate having a diameter of 20 cm and a thickness of 1 mm was attached to the surface opposite to the surface attached to the silicon wafer.
For initial adhesion evaluation, after placing the silicon wafer on the suction table so that the glass is on the top surface, the glass edge can be pulled with a suction cup and the glass cannot be peeled at all. The case where the film was peeled off with almost no resistance was evaluated as “×”.

(2) Evaluation of heat resistance The adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer (circuit wafer) having a thickness of 700 μm on which a circuit having a diameter of 20 cm and a step of about 5 μm was formed. In this state, it was heated at 260 ° C. for 10 minutes. The adhesive surface between the heated adhesive tape and the silicon wafer was visually observed, and “◎” indicates that no lifting was observed over the entire surface, and “0.3” indicates that the lifting was less than 3% of the entire area. The case where the float was 3% or more and less than 10% of the entire area was evaluated as “Δ”, and the case where the float was 10% or more of the entire area was evaluated as “X”.

(3) Evaluation of peelability An adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer (circuit wafer) having a thickness of 700 μm on which a circuit having a diameter of 20 cm and a step of about 5 μm was formed. In this state, it was heated at 260 ° C. for 10 minutes.
After heating, pasting a dicing tape on the side of the surface not adhering to the adhesive tape of the silicon wafer, adsorbed and fixed, illuminance 254nm using an extra-high pressure mercury lamp from the Tempax glass side, the light intensity 70 mW / cm ² Irradiated for 150 seconds. Thereafter, the glass was peeled off and the adhesive tape was peeled off. When the surface of the silicon wafer from which the adhesive tape has been peeled is visually observed, “◎” indicates that no adhesive residue is present, and “◯” indicates that the adhesive residue is less than 2% of the total area. The case where the remainder was less than 5% of the entire area was evaluated as “Δ”, and the case where it was 5% or more of the entire area of the adhesive remaining was evaluated as “x”.
In Comparative Examples 1, 2, and 3, since peeling was observed in 10% or more of the entire area when heated at 260 ° C. for 10 minutes, the peelability evaluation was not performed.

(Examples 8 to 10, Comparative Example 5)
(1) Preparation of photocurable (meth) acryl-silicone copolymer A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared. In this reactor, 74 parts by weight of 2-ethylhexyl acrylate, acrylic 1 part by weight of acid, 5 parts by weight of 2-hydroxyethyl acrylate, 20 parts by weight of silicone methacrylate, 0.01 part by weight of lauryl mercaptan and 80 parts by weight of ethyl acetate were added, and the reactor was heated to start refluxing. Subsequently, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator in the reactor, and polymerization was started under reflux. It was. Next, after 1 hour and 2 hours from the start of polymerization, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added, and the polymerization was started. 4 hours later, 0.05 part by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. Then, 8 hours after the start of polymerization, an acrylic copolymer having a solid content of 55% by weight and a weight average molecular weight of 700,000 was obtained.

(2) Production of pressure-sensitive adhesive composition and pressure-sensitive adhesive tape For the photocurable (meth) acryl-silicone copolymer obtained, EBECRYL350 (manufactured by Daicel Cytec, acrylic equivalent 2) as a silicone oligomer, and As a urethane acrylate oligomer, UN5500 (manufactured by Negami Kogyo Co., Ltd.) was blended according to the composition shown in Table 2 to obtain a resin mixture. Methyl ethyl ketone and fumed silica (manufactured by Tokuyama, MT10) were blended into the obtained resin mixture, and fumed silica was dispersed to the average particle size shown in Table 2 using a homogenizer to prepare an adhesive composition.

A doctor knife so that the ethyl acetate solution of the obtained pressure-sensitive adhesive composition has a dry film thickness of 30 μm on the corona-treated surface of a transparent polyethylene naphthalate film having a thickness of 50 μm that has been corona-treated on one side. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Examples 11 to 16, Comparative Examples 6, 9, and 10)
(1) Preparation of photocurable (meth) acryl-silicone copolymer A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared. In this reactor, 54 parts by weight of 2-ethylhexyl acrylate, acrylic After adding 1 part by weight of acid, 5 parts by weight of 2-hydroxyethyl acrylate, 40 parts by weight of silicone methacrylate, 0.01 part by weight of lauryl mercaptan, and 80 parts by weight of ethyl acetate, the reactor was heated to start refluxing. Subsequently, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator in the reactor, and polymerization was started under reflux. It was. Next, after 1 hour and 2 hours from the start of polymerization, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added, and the polymerization was started. 4 hours later, 0.05 part by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. And 8 hours after the start of polymerization, an acrylic copolymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.

(2) Production of pressure-sensitive adhesive composition and pressure-sensitive adhesive tape For the photocurable (meth) acryl-silicone copolymer obtained, EBECRYL350 (manufactured by Daicel Cytec, acrylic equivalent 2) as a silicone oligomer, and As a urethane acrylate oligomer, UN5500 (manufactured by Negami Kogyo Co., Ltd.) was blended according to the composition shown in Table 2 to obtain a resin mixture. Methyl ethyl ketone and fumed silica (manufactured by Tokuyama, MT10) were blended into the obtained resin mixture, and fumed silica was dispersed to the average particle size shown in Table 2 using a homogenizer to prepare an adhesive composition.

A doctor knife so that the ethyl acetate solution of the obtained pressure-sensitive adhesive composition has a dry film thickness of 30 μm on the corona-treated surface of a transparent polyethylene naphthalate film having a thickness of 50 μm that has been corona-treated on one side. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Comparative Examples 7 and 8)
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared. In this reactor, 94 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of acrylic acid, 5 parts by weight of 2-hydroxyethyl acrylate, 0.01% lauryl mercaptan After adding parts by weight and 80 parts by weight of ethyl acetate, the reactor was heated to start refluxing. Subsequently, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator in the reactor, and polymerization was started under reflux. It was. Next, after 1 hour and 2 hours from the start of polymerization, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added, and the polymerization was started. 4 hours later, 0.05 part by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. And 8 hours after the start of polymerization, an acrylic copolymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.

To the obtained acrylic polymer, methyl ethyl ketone and fumed silica (manufactured by Tokuyama, MT10) are blended, and the fumed silica is dispersed to the average particle size shown in Table 2 using a homogenizer, and an adhesive composition is prepared. Prepared.

A doctor knife so that the ethyl acetate solution of the obtained pressure-sensitive adhesive composition has a dry film thickness of 30 μm on the corona-treated surface of a transparent polyethylene naphthalate film having a thickness of 50 μm that has been corona-treated on one side. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Evaluation)
About the adhesive composition and adhesive tape obtained by the Example and the comparative example, it evaluated by the method similar to the above.
The results are shown in Table 2.
In Comparative Examples 5, 6, 7, and 9, since peeling was observed in 10% or more of the entire area when heated at 260 ° C. for 10 minutes, the peelability evaluation was not performed.

According to the present invention, it has an initial adhesive force necessary and sufficient for fixing an adherend, and can be easily peeled off without being left behind even after a high temperature processing process of 200 ° C. or higher. It is possible to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition, and a wafer processing method using the pressure-sensitive adhesive composition.

Claims (10)

A pressure-sensitive adhesive composition comprising a silicone pressure-sensitive adhesive and fumed silica having an average particle size of 0.05 to 3 μm. The pressure-sensitive adhesive composition according to claim 1, wherein the silicone pressure-sensitive adhesive is a copolymer of a (meth) acrylic monomer and a silicone (meth) acrylate. The pressure-sensitive adhesive composition according to claim 2, wherein the copolymer of the (meth) acrylic monomer and the silicone (meth) acrylate has photocurability. The pressure-sensitive adhesive composition according to claim 3, further comprising a photopolymerization initiator. The pressure-sensitive adhesive composition according to claim 3, comprising a photo-curable (meth) acrylic monomer and silicone (meth) acrylate copolymer and a silicone compound having a crosslinkable functional group. The pressure-sensitive adhesive composition according to claim 1, comprising a urethane acrylate oligomer. The pressure-sensitive adhesive composition according to claim 1, comprising a gas generating agent that generates gas when irradiated with light. The pressure-sensitive adhesive composition according to claim 7, wherein the gas generating agent is a salt of a tetrazole compound. A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition according to claim 1, 2, 3, 4, 5, 6, 7, or 8 on at least one surface of a substrate. A support plate fixing step for fixing a wafer to a support plate through the pressure-sensitive adhesive composition of the pressure-sensitive adhesive composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8, and fixing to the support plate A wafer processing step for subjecting the surface of the wafer to a treatment involving heating at 200 ° C. or more; and a support for irradiating the processed wafer with light to cure the pressure-sensitive adhesive composition and peeling the support plate from the wafer. A wafer processing method comprising: a plate peeling step.