JPH11307620A - Surface protective tape for semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold down the contamination due to components of an adhesive layer to an extremely low level by forming the adhesive layer on a base film from an acrylic adhesive, including a fluorocarbon surface active agent made of polyoxyethylene alkylester fluoride. SOLUTION: On a release-type film, a fluorocarbon surface active agent made of polyoxyethylene alkylester fluoride having the number average molecular weight of 4,000-10,000 and the weight average molecular weight of 5,000-20,000 is impregnated with an acrylic copolymer made by copolymerizing a monomer, such as methyl acrylate, methyl methacrylate, ethyl acrylate, and ethyl methacrylate and a monomer having a functional group reactive with a hardener and with an acrylic adhesive including a hardener as an indispensable component. An adhesive layer made by applying and drying the solution of the acrylic adhesive is transferred onto the base film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protection tape for a semiconductor used for protecting a surface of a semiconductor wafer on which a circuit pattern is formed in a process of manufacturing a semiconductor integrated circuit chip.

[0002]

2. Description of the Related Art In a process of manufacturing a semiconductor integrated circuit chip, usually, a back surface of a wafer on which a circuit pattern is formed is ground so as to be adjusted to a thickness according to a use. When grinding the back surface of the wafer, a method of attaching a surface protection tape to the circuit pattern forming surface is known to prevent the wafer from being damaged and the circuit pattern forming surface from being contaminated.

[0003] Surface protection tapes for semiconductors are generally formed by providing an adhesive layer on a base film, and have sufficient adhesive strength to protect the circuit pattern surface during use.
In addition, there is a demand for a property that the wafer is not contaminated by the adhesive layer component after peeling. Therefore, various methods for improving the characteristics of the pressure-sensitive adhesive layer have been proposed.

[0004]

However, in recent years, as the density and performance of semiconductor integrated circuits have increased, the control of contamination on the circuit surfaces of semiconductor wafers and semiconductor chips has become stricter, and has not been a problem in the past. Foreign matter of a size is also being managed. For this reason, surface protection tapes for semiconductors are required to have a higher level of low contamination than ever before.

The present invention has been made to meet such a demand, and an object of the present invention is to provide a surface protection tape for semiconductors in which contamination due to an adhesive layer component generated on the back surface of a wafer after peeling is suppressed to a very low level. .

[0006]

That is, according to the present invention, in a surface protection tape for semiconductor comprising an adhesive layer provided on a substrate film, the adhesive layer is made of a fluorine-containing polyoxyethylene fluorinated alkyl ester. A surface protective tape for a semiconductor, comprising an acrylic pressure-sensitive adhesive containing a surfactant, is provided.

Conventionally, a pressure-sensitive adhesive tape, label or sheet containing a fluorine-containing surfactant in a pressure-sensitive adhesive composition for the purpose of facilitating release from a release paper (JP-A-5-25450) ) Has been proposed. However, even if a fluorinated surfactant is simply blended, the performance is insufficient for the purpose of sticking to a circuit pattern forming surface of a semiconductor wafer as in the present invention.

The present inventors have studied various fluorine-based surfactants, and as a result, have found that a fluorine-based surfactant comprising a polyoxyethylene fluorinated alkyl ester is effective, and have accomplished the present invention.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surface protection tape for semiconductors of the present invention is obtained, for example, by applying a solution of an acrylic pressure-sensitive adhesive containing a fluorine-based surfactant comprising a polyoxyethylene fluorinated alkyl ester onto a release film. It can be manufactured by transferring an adhesive layer obtained by drying onto a substrate film.

The fluorinated surfactant comprising a polyoxyethylene fluorinated alkyl ester used in the present invention has a number average molecular weight (Mn) of 4,000 to 100.
00, weight average molecular weight (Mw) 5,000 to 20,000
Are preferred. Specifically, Sumitomo 3M
Brand name Florard FC-430, Florard FC-43
Commercial products such as No. 1 can be used.

The compounding amount is the pressure-sensitive adhesive polymer 10 described later.
0.1 to 2.0 parts by weight, more preferably 0.5 to 1.0 parts by weight, based on 0 parts by weight. If the amount is less than 0.1 part by weight, the effect of reducing the amount of foreign matter adhering detected on the wafer surface is not recognized. If it exceeds 2.0 parts by weight, the effect of reducing the amount of foreign particles detected on the wafer surface is not recognized, and the amount of foreign particles attached increases rather.

Fluorinated surfactants other than polyoxyethylene fluorinated alkyl esters, for example, RfSO ₂ N
(R) C ₂ H ₄ OH or RfSO ₂ N (R) (C ₂ H
_{When 4} O) ₂₀ H (Rf: perfluoroalkyl group, R: alkyl group) is used, the amount of foreign matter attached becomes extremely large.

The acrylic pressure-sensitive adhesive contains a (meth) acrylic copolymer and a curing agent as essential components.

The (meth) acrylic copolymer is obtained by copolymerizing a monomer (1) such as an alkyl acrylate and a monomer (2) having a functional group capable of reacting with a curing agent described later.

Examples of the monomer (1) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate and the like. These may be used alone or as a mixture of two or more.

As the monomer (2), acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid,
Examples include fumaric acid, maleic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. These may be used alone or as a mixture of two or more.

The (meth) acrylic copolymer can be obtained by copolymerizing the above monomers (1) and (2) by a conventional solution polymerization method.

The curing agent is used for adjusting the adhesive force and cohesive force by reacting with the functional group of the (meth) acrylic copolymer. For example, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N-diglycidylaminomethyl) toluene, 1,3-bis (N, N-diglycidylaminomethyl) B.) Benzene, N, N, N ', N'-tetraglycidyl-m-xylenediamine and the like epoxy compounds having two or more epoxy groups in a molecule, 2,4-tolylenediisocyanate, 2,6-tolylene Diisocyanate, 1,3-xylylene diisocyanate, 1,4
-Xylene diisocyanate, diphenylmethane-4,
An isocyanate compound having two or more isocyanate groups in a molecule such as 4′-diisocyanate, tetramethylol-tri-β-aziridinylpropionate,
Trimethylol-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-
Aziridine compounds having two or more aziridinyl groups in the molecule, such as (2-methylaziridine) propionate, are exemplified.

The amount of the curing agent to be added may be adjusted according to the desired adhesive strength, and is suitably from 0.1 to 5.0 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.

The adhesive strength is measured according to JIS Z 0237 (199).
The value measured according to 1) (90 ° peeling method, peeling speed: 50 mm / min, test plate: silicon wafer) is 0.
It is preferably about 2 to 1.3 N / 25 mm.

Examples of the solvent for the acrylic pressure-sensitive adhesive include ethyl acetate, toluene, xylene, acetone, methyl ethyl ketone, n-hexane and cyclohexane.

The material of the base film is polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, ethylene-vinyl acetate copolymer, ethylene-
Ethyl acrylate copolymer, α-olefin homopolymer or copolymer such as ionomer, engineering plastics such as polyethylene terephthalate, polycarbonate, polymethyl methacrylate, or polyurethane, styrene-ethylene-butene or pentene copolymer, etc. Thermoplastic elastomers.
Alternatively, a mixture of two or more selected from these groups may be used, and it can be arbitrarily selected depending on the adhesiveness to the pressure-sensitive adhesive layer. The thickness of the base film is 30 to 300
μm is appropriate.

[0023]

EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 100 parts by weight of a copolymer of 2-ethylhexyl acrylate and acrylic acid were mixed with a curing agent and a fluorinated surfactant at the compounding ratio shown in Table 1, and ethyl acetate was added to obtain a solid content. Was adjusted to be 29% to prepare an adhesive coating solution. The prepared pressure-sensitive adhesive coating liquid was applied to a silicone release-treated polyethylene terephthalate tape (thickness: 38 μm) at a linear velocity of 2 m / min using a comma coater, and passed through a hot air drying oven set at 110 ° C. to perform corona treatment. Laminated film of ethylene vinyl acetate / polyethylene / ethylene vinyl acetate
m) to prepare a surface protection tape for semiconductors with a release film having a coating thickness of 30 μm after drying.

(Examples 2 to 4) (Comparative Examples 1 to 4) Surface protective tapes for semiconductors in the same procedure as in Example 1 using the pressure-sensitive adhesive polymer, curing agent and fluorine-based surfactant shown in Table 1. Was prepared.

Regarding the obtained surface protection tape, (1)
The adhesive force and (2) the state of foreign matter remaining on the silicon wafer surface after the tape was peeled were examined as follows.

(1) Adhesive strength A surface protection tape cut into a strip having a width of 25 mm is adhered to a mirror surface (5 inches φ) of a silicon wafer.
0237 (1991), 90 ° peeling method,
The adhesive strength was measured at a peeling speed of 50 mm / min.

(2) Foreign matter remaining state A surface protection tape was adhered to a mirror surface (6 inches φ) of a silicon wafer whose surface was washed, left for 24 hours, and then the surface protection tape was peeled off. The number of foreign substances remaining on the surface of the wafer to which the surface protection tape has been adhered is determined using a laser surface inspection device (Surfscan 6420: KLA Tencor).
(Manufactured by K.K.). The obtained results were determined based on the following evaluation criteria. ◎: less than 20 ○: 20 or more and less than 90 △: 90 or more and less than 200 ×: 200 or more

[0028]

[Table 1]

In Comparative Example 1, foreign substances remained because no fluorine-based surfactant comprising a polyoxyethylene fluorinated alkyl ester was added. In Comparative Example 2, a fluorine-based surfactant different from polyoxyethylene fluorinated alkyl ester was blended in the pressure-sensitive adhesive layer.
Although the foreign matter having a size of 30 μm or more was excellent, the content of 0.
Many foreign substances of 15 μm or more remained. In Comparative Example 3, a fluorine-based surfactant different from polyoxyethylene fluorinated alkyl ester was blended in the pressure-sensitive adhesive layer,
The foreign matter having a size of 0.30 μm or more was very good, but a large amount of foreign matter having a size of 0.15 μm or more remained. Comparative Example 4
In this example, the adhesive strength is almost the same as that of Example 1 because a larger amount of the curing agent is blended than in Comparative Example 1. However, the fluorine-based surfactant composed of polyoxyethylene fluorinated alkyl ester in the adhesive layer Was not blended, so that foreign matter remained. In Examples 1 to 4, the fluorine-based surfactant composed of polyoxyethylene fluorinated alkyl ester was contained in the pressure-sensitive adhesive layer, so that a very small amount of foreign matter of 0.30 μm remained, and a foreign matter of 0.15 μm or more. Was also trace amount.

[0030]

According to the surface protection tape for semiconductors of the present invention, since the pressure-sensitive adhesive layer contains a fluorine-based surfactant composed of polyoxyethylene fluorinated alkyl ester, the surface protection tape adheres when the surface protection tape is peeled off. It has the property that the foreign matter due to the adhesive layer component is extremely small on the tape release surface of the body, and can be suitably used for protecting the surface of a wafer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toyohiro Matsumura 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd.

Claims (2)

[Claims] 1. An acrylic pressure-sensitive adhesive comprising a fluorine-containing surfactant comprising a polyoxyethylene fluorinated alkyl ester, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive layer provided on a substrate film. A surface protection tape for semiconductors, comprising: 2. The polyoxyethylene fluorinated alkyl ester has a number average molecular weight (Mn) of 4,000 to 1,000.
The surface protection tape for semiconductors according to claim 1, wherein the weight average molecular weight (Mw) is 5,000 to 20,000.