JP2009001773A - Tape for semiconductor processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tape for semiconductor processing which is attached to a semiconductor for protecting the same at semiconductor processing, provided that semiconductor processing comprises a vacuum heat treatment step. <P>SOLUTION: The tape for semiconductor processing has an adhesive layer on at least one side of a substrate, provided that the adhesive layer contains 5-20 pts.wt. fumed silica having an average particle size of from 7 nm to 2 μm based on 100 pts.wt. photocurable adhesive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a semiconductor processing tape for attaching to a semiconductor and protecting it during processing of a semiconductor having a vacuum heating process.

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.

However, when an adhesive tape using such a photo-curable adhesive is used when processing a semiconductor having a step of heating under vacuum such as a thin film forming step or a sputtering step by a chemical vapor deposition method (CVD) method Even before the irradiation with ultraviolet rays or the like, there has been a problem that peeling may occur during the heating process. Such peeling was particularly noticeable when irregularities such as circuits were formed on the non-contact surface.
JP-A-5-32946

An object of this invention is to provide the tape for semiconductor processing for sticking to a semiconductor and protecting this at the time of the processing of the semiconductor which has a vacuum heating process.

The present invention is a semiconductor processing tape for protecting and protecting a semiconductor during processing of a semiconductor having a vacuum heating process, and is provided with 100 parts by weight of a photocurable adhesive on at least one surface of a substrate. Is a tape for semiconductor processing having an adhesive layer containing 5 to 20 parts by weight of fumed silica having an average particle diameter of 7 nm to 2 μm.
The present invention is described in detail below.

When sticking an adhesive tape on the surface of a semiconductor, the sticking process is usually performed under reduced pressure so as not to bite bubbles or the like. However, it is extremely difficult to completely prevent bubbles from being caught. In particular, when unevenness such as a circuit is formed on the non-contact surface, it is inevitable that bubbles remain in the vicinity of the unevenness. Although such bubbles are not a problem in the normal process, they expand when placed under vacuum in a process such as a thin film formation process by chemical vapor deposition (CVD) or a heating process such as a sputtering process. , Pressure to try to peel. On the other hand, the pressure-sensitive adhesive generally tends to decrease in adhesive strength as the temperature increases. The cause of peeling when a pressure-sensitive adhesive tape using a conventional photo-curing type adhesive is used when processing a semiconductor having a vacuum heating process is due to the high temperature against the peeling pressure generated by expansion of bubbles by vacuum heating. It was thought that the adhesive with reduced adhesive strength could not be resisted.
As a result of intensive studies, the inventors have used a fumed silica having a specific average particle size in a specific ratio in the pressure-sensitive adhesive layer, thereby being used when processing a semiconductor having a vacuum heating step. Has also found that the occurrence of peeling can be effectively suppressed, and has led to the completion of the present invention.

According to the conventional concept, it has been thought that the adhesive strength of the pressure-sensitive adhesive layer containing silica increases rather than the elastic modulus (E ′ or G ′) increases (hardens). Surprisingly, however, the pressure-sensitive adhesive layer containing fumed silica has a remarkably improved peel strength at high temperature, and does not peel easily even when a peel pressure generated by the expansion of bubbles is applied. Although the reason for this is not clear, it is considered that the fluid component maintains the adhesive force while the sea-island structure, which is pseudo-crosslinking, maintains the structure at a high temperature.

The tape for semiconductor processing of the present invention has an adhesive layer on at least one surface of a substrate.
The semiconductor processing tape of the present invention may be a single-sided adhesive tape having an adhesive layer formed on only one side, or a double-sided adhesive tape having an adhesive layer formed on both sides.

Although it does not specifically limit as said base material, It is preferable that it is what permeate | transmits or passes light, For example, transparent, such as an acryl, an olefin, a polycarbonate, vinyl chloride, ABS, a polyethylene terephthalate (PET), nylon, urethane, a polyimide And a sheet made of a simple resin, a sheet having a network structure, a sheet having holes, and the like.

The pressure-sensitive adhesive layer contains a photocurable pressure-sensitive adhesive and fumed silica.
It does not specifically limit as said photocurable adhesive, A conventionally well-known thing can be used. Specifically, for example, a (meth) acrylic acid alkyl ester-based polymerizable polymer having a radical polymerizable unsaturated bond in the molecule and a radical polymerizable polyfunctional oligomer or monomer as main components are necessary. The thing using the photocurable adhesive which contains a photoinitiator according to it, etc. are mentioned.
The pressure-sensitive adhesive layer made of such a photo-curable pressure-sensitive adhesive is uniformly and rapidly polymerized and integrated by light irradiation, so that the elastic modulus increases significantly due to polymerization and curing. Adhesive strength is greatly reduced.

The polymerizable polymer is prepared by, for example, previously synthesizing a (meth) acrylic polymer having a functional group in the molecule (hereinafter referred to as a functional group-containing (meth) acrylic polymer) and reacting with the functional group in the molecule. It can obtain by making it react with the compound (henceforth a functional group containing unsaturated compound) which has a functional group to perform and a radically polymerizable unsaturated bond.

The functional group-containing (meth) acrylic polymer is an acrylic having an alkyl group usually in the range of 2 to 18 as a polymer having adhesiveness at room temperature, as in the case of a general (meth) acrylic polymer. By copolymerizing an acid alkyl ester and / or methacrylic acid alkyl ester as a main monomer, a functional group-containing monomer, and, if necessary, another modifying monomer copolymerizable therewith by a conventional method It is obtained. The weight average molecular weight of the 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 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 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. it can. 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 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. As such more preferred polyfunctional oligomers or monomers, for example, 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.

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.

The lower limit of the average particle diameter of the fumed silica is 7 nm, and the upper limit is 2 μm. Fumed silica of less than 7 μm is not practically available, and if it exceeds 2 μm, fine dispersion, which is a characteristic of the pressure-sensitive adhesive, cannot be made before the evaluation of physical properties. A preferred lower limit is 15 μm and a preferred upper limit is 1 μm.

The blending amount of the fumed silica is such that the lower limit with respect to 100 parts by weight of the photocurable pressure-sensitive adhesive is 5 parts by weight and the upper limit is 20 parts by weight. If it is less than 5 parts by weight, the effect of preventing peeling under vacuum heating is insufficient, and if it exceeds 20 parts by weight, an adhesive at room temperature can be applied on the film, and the adhesive strength is appropriate. It is difficult to release the fumed silica and the fumed silica cannot be kneaded into the adhesive. A preferred lower limit is 8 parts by weight and a preferred upper limit is 15 parts by weight.

The pressure-sensitive adhesive layer may contain a gas generating agent that generates gas when irradiated with light. When the pressure-sensitive adhesive layer containing such a gas generating agent is irradiated with light, the photo-curing pressure-sensitive adhesive is cross-linked and cured, and the elastic modulus of the entire pressure-sensitive adhesive layer increases, and is generated in such a hard pressure-sensitive adhesive layer. Since the released gas is released from the pressure-sensitive adhesive layer to the adhesive interface and peels at least a part of the adhesive surface, the pressure-sensitive adhesive tape can be peeled off more easily.

Although it does not specifically limit as said gas generating agent, For example, an azide compound, an azo compound, etc. are mentioned. Among these, considering that the semiconductor processing tape of the present invention is used when processing a semiconductor having a vacuum heating step, an azide compound having excellent heat resistance is preferable.
The azide compound is not particularly limited. For example, 3-azidomethyl-3-methyloxetane, terephthalazide, p-tert-butylbenzazide; glycidyl obtained by ring-opening polymerization of 3-azidomethyl-3-methyloxetane Examples thereof include a polymer having an azide group such as an azide polymer (GAP).

The pressure-sensitive adhesive layer may appropriately contain various polyfunctional compounds that are blended in a general pressure-sensitive adhesive such as an isocyanate compound, a melamine compound, and an epoxy compound for the purpose of adjusting the cohesive force as the pressure-sensitive adhesive. In addition, known additives such as an antistatic agent, a plasticizer, a resin, a surfactant, a wax, and a fine particle filler can be added. Furthermore, you may mix | blend a heat stabilizer and antioxidant in order to improve stability of an adhesive.

The method for producing the semiconductor processing tape of the present invention is not particularly limited, and for example, a conventionally known method such as coating the above-mentioned pressure-sensitive adhesive or the like on a substrate using a doctor knife, a spin coater or the like is used. be able to.

The tape for semiconductor processing of the present invention can be suitably used for sticking to a semiconductor and protecting it during processing of the semiconductor having a vacuum heating step. The tape for semiconductor processing of the present invention has a high adhesive strength to a semiconductor at room temperature, and can maintain a sufficiently high adhesive strength even when heated under vacuum. Therefore, in a process of heating under vacuum such as a thin film forming process or a sputtering process by a chemical vapor deposition method (CVD) method, peeling pressure is generated due to expansion of bubbles remaining on the non-attached surface by being placed under vacuum. However, it does not easily peel off.

ADVANTAGE OF THE INVENTION According to this invention, the semiconductor processing tape for sticking to a semiconductor and protecting this at the time of the process of the semiconductor which has a vacuum heating process can be provided.

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.

(Example 1)
(1) Preparation of photocurable pressure-sensitive adhesive The following compounds are dissolved in ethyl acetate, polymerized by irradiation with ultraviolet rays, and an ethyl acetate solution of a photocurable pressure-sensitive adhesive made of an acrylic copolymer having a weight average molecular weight of 700,000. Got.
Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-hydroxyethyl acrylate 5 parts by weight Photopolymerization initiator 0.2 part by weight (Irgacure 651, 50% ethyl acetate solution)
Lauryl mercaptan 0.01 parts by weight

(2) Preparation of composition solution for pressure-sensitive adhesive layer The reaction was conducted by adding 3.5 parts by weight of 2-isocyanatoethyl methacrylate to 100 parts by weight of the resin solid content of the obtained ethyl acetate solution of the photocurable pressure-sensitive adhesive. Furthermore, 10 parts by weight of fumed silica (manufactured by Tokuyama, MT10: average particle size 15 nm), 100% by weight of the resin solid content of the ethyl acetate solution after the reaction, 0.1% of the photopolymerization initiator (Irgacure 651). 2 parts by weight and 0.5 parts by weight of polyisocyanate were mixed to prepare an adhesive layer composition solution.

(3) Manufacture of semiconductor processing tape The thickness of the dried film on the corona treatment of a 75 μm-thick transparent polyethylene terephthalate (PET) film obtained by subjecting the obtained composition solution for pressure-sensitive adhesive layer to corona treatment on one side Was applied with a doctor knife so as to be about 15 μm, and heated at 110 ° C. for 5 minutes to dry the coating solution. The pressure-sensitive adhesive layer after drying showed adhesiveness in a dry state. Next, a PET film that was subjected to a release treatment was attached to the surface of the pressure-sensitive adhesive layer. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain a semiconductor processing tape.

(Examples 2-5, Comparative Examples 1-5)
A composition solution for a pressure-sensitive adhesive layer was prepared in the same manner as in Example 1 except that the type and blending amount of fumed silica were as shown in Table 1, and a semiconductor processing tape was produced using the same.

(Evaluation)
About the tape for semiconductor processing manufactured in Examples 1-5 and Comparative Examples 1-5, evaluation was performed with the following method.
The results are shown in Table 1.

(Evaluation of resistance to vacuum heating)
The obtained semiconductor processing tape was used as a back surface grinding tape, and was affixed to a silicon wafer having a thickness of 200 μm on which a circuit was formed in a room temperature vacuum. Subsequently, it left still in a vacuum bonding machine and was vacuum-heat-processed for 20 minutes on 100 Pa and 130 degreeC conditions.
The test was carried out 10 times for each semiconductor processing tape, and the number where peeling did not occur during processing was determined.

ADVANTAGE OF THE INVENTION According to this invention, the semiconductor processing tape for sticking to a semiconductor and protecting this at the time of the process of the semiconductor which has a vacuum heating process can be provided.

Claims (2)

A semiconductor processing tape for attaching to and protecting a semiconductor during processing of a semiconductor having a vacuum heating process,
It has an adhesive layer containing 5 to 20 parts by weight of fumed silica having an average particle diameter of 7 nm to 2 μm with respect to 100 parts by weight of the photocurable adhesive on at least one surface of the substrate. Features semiconductor processing tape. The pressure-sensitive adhesive layer further contains a gas generating agent, and is a tape for semiconductor processing.