JP2919601B2 - Wafer processing film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wafer processing film for use in polishing a silicon wafer or the like for preventing damage.

[Conventional technology]

Semiconductor integrated circuits (ICs) are usually manufactured by slicing high-purity silicon single crystals or the like into wafers, incorporating the integrated circuits by etching, etc., and dicing into chips. In order to prevent breakage of wafers such as silicon, and to facilitate processing,
2. Description of the Related Art A wafer processing film that is adhered to a wafer surface via an adhesive layer is used.

At this time, in general, after the wafer processing film is used for wafer processing, cleaning is performed to remove deposits on the wafer surface.

The adhesive generally includes a solvent-based adhesive and an aqueous emulsion adhesive.

When using a film with a solvent-based adhesive,
Hydrophobic deposits remain, water cannot be removed completely by washing, and organic solvent washing is performed, but it takes time and effort,
There are also problems in terms of safety and hygiene.

In order to solve these problems, Japanese Patent Publication No. 1-51511 discloses a processing film in which a surfactant is added to an aqueous emulsion pressure-sensitive adhesive, and JP-A-62-1101678 discloses that a surfactant is added to a solvent-based pressure-sensitive adhesive. The proposed processing film has been proposed, and after use, deposits are removed by washing with water.

However, after the wafer processing film is used for wafer processing, it is necessary to perform cleaning to remove contamination on the wafer surface, which is troublesome and induces secondary contamination in the cleaning and drying processes. There were drawbacks.

[Problems to be solved by the invention]

In view of the above, an object of the present invention is to provide a wafer processing film that does not require cleaning.

[Means for solving the problem]

The present inventors have conducted intensive studies on the pressure-sensitive adhesive in order to achieve the above object. As a result, in the pressure-sensitive adhesive using a normal surfactant, the surfactant is present on the pressure-sensitive adhesive surface, and after being attached to the wafer, the wafer surface is The surfactant is transferred to the surface of the wafer, but in the case of the reactive surfactant, since the surfactant is incorporated into the molecular chains of the resin, the surfactant is not present only on the surface of the adhesive. The present inventors have found that the surfactant does not transfer to the wafer surface even after attaching to the substrate, and completed the present invention.

That is, the present invention provides a film for wafer processing in which an adhesive layer is provided on one side of a base film, wherein an aqueous emulsion adhesive using a reactive surfactant is used as a surfactant during polymerization of the adhesive. Characteristic film for wafer processing.

The wafer to be used for the film for wafer processing of the present invention includes not only silicon but also wafers of germanium, gallium-arsenic, gallium-phosphorus, gallium-arsenic-aluminum and the like.

The water-based emulsion pressure-sensitive adhesive referred to in the present invention is not particularly limited, and known ones such as acrylic and sesame can be used.

The acrylic pressure-sensitive adhesive referred to herein includes, for example, acrylic acid such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, butyl methacrylate, etc., esters such as methacrylic acid, acrylic acid, methacrylic acid, acrylic 2-hydroxyethyl acid, acrylamide, methacrylamide, acryl having a functional group such as acrylonitrile, a monomer such as a methacrylic compound or the like, a reactive surfactant, ion-exchanged water or pure water, and a polymerization initiator are added. Is an adhesive that has been emulsion polymerized.

The selection of the monomer composition can be appropriately selected according to the required adhesive strength.

Further, as the reactive surfactant at the time of polymerization used in the present invention, any one having a vinyl group in the molecule can be appropriately selected.

For example, a compound in which an allyl group is added to the benzene ring of polyoxyethylene alkyl phenyl ether, a compound in which an allyl group is added to the benzene ring of polyoxyethylene alkyl phenyl ether sulfate, a higher alcohol to maleic acid And a compound obtained by adding a sulfate to a compound obtained by adding an allyl group.

Preferably, it is a nonionic surfactant or an anionic surfactant which is an ammonium salt.

In the case of the anionic surfactants of soda salt and potassium salt, sodium ions and potassium ions remaining in the adhesive may cause corrosion of the wafer.

Further, the amount of the surfactant to be added is 0.05 to 10.0 parts by weight based on 100 parts by weight of the monomer.

 More preferably, the amount is 0.1 to 5.0 parts by weight.

If the amount is less than 0.05 part by weight, stability during polymerization is poor, many aggregates are generated, and the yield is poor.

If the amount exceeds 10.0 parts by weight, the resulting adhesive film absorbs water, resulting in poor water resistance.

The wafer processing film of the present invention is obtained by applying a pressure-sensitive adhesive to a base film, drying the film, and then adhering a separator to the pressure-sensitive adhesive layer.

As the base film used in the present invention, a film made of a synthetic resin or natural or synthetic rubber can be appropriately selected.

If exemplified as the composition of the base film, thermoplastic elastomers such as ethylene-vinyl acetate copolymer, polybutadiene, soft vinyl chloride resin, polyolefin, polyester, polyamide, and the like, and diene, nitrile, silicone, acrylic, etc. Of synthetic rubber.

The thickness of the base film is appropriately determined depending on conditions such as the shape and surface state of the wafer to be protected, the polishing method, and the like, and is usually preferably 10 μm to 2000 μm.

The thickness of the pressure-sensitive adhesive provided on the surface of the base film is appropriately determined depending on the surface condition, shape, polishing method, and the like of the wafer, and is usually 2 μm to 100 μm. Preferably it is 5 μm to 50 μm.

As a method of applying the pressure-sensitive adhesive to the base film surface, a conventionally known coating method, for example, a roll coater method, a gravure roll method, a bar coating method, or the like can be adopted, and the pressure-sensitive adhesive can be applied to one entire surface of the base film.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

 The evaluation in this example was performed by the following method.

Contamination degree of wafer surface As a standard wafer, a 4-inch mirror wafer was used whose surface area ratio of oxygen and carbon peaks was 0.10 when the surface was analyzed by ESCA.

When the wafer surface is contaminated with the adhesive, the carbon content increases, the ratio of the peak area values of carbon and silicon becomes larger than 0.10, and the degree of contamination can be measured.

 The degree of contamination was measured at this ratio.

 ESCA measurement equipment and measurement conditions.

Equipment: ESCA LAB MK II manufactured by VACUUNGENERATOR X-ray source: Mg kα ray X-ray output: 300 W Measurement vacuum degree: 1 × 10 ^-9 mbar or less Number of foreign particles on wafer surface Laser surface inspection system HLD- manufactured by Hitachi Electronics Engineering Co., Ltd. The number of foreign substances on the wafer surface was examined using 300B.

The film of the pressure-sensitive adhesive prepared on the water-resistant glass plate was immersed in water, and the time until the film was whitened was measured.

Example 1 A flask equipped with a thermometer, a reflux condenser, a dropping funnel, a nitrogen inlet and a stirrer was charged with 150 parts by weight of ion-exchanged water,
As a surfactant, 2 parts by weight of a compound obtained by adding an allyl group to a benzene ring of polyoxyethylene nonylphenyl ether (ethylene oxide 20 mol) was added, and the temperature was raised to 70 ° C. while stirring under a nitrogen atmosphere.

Next, as a polymerization initiator, ammonium peroxide 0.5
100 parts by weight of a monomer mixture consisting of 70 parts by weight of 2-ethylhexyl acrylate, 25 parts by weight of methyl methacrylate, 3 parts by weight of methacrylic acid, and 2 parts by weight of 2-hydroxyethyl acrylate were added in 4 hours by weight. Continuous dropping was carried out, and polymerization was continued with stirring for 3 hours after the completion of dropping to obtain an acrylic emulsion-based pressure-sensitive adhesive having a solid content of about 40% by weight.

Next, 10 parts by weight of diethylene glycol monobutyl ether was added to 100 parts by weight of the pressure-sensitive adhesive to prepare a coating solution, and applied to a corona-treated one side of a 150 μm-thick ethylene-vinyl acetate copolymer film by a roll coater,
After drying at 105 ° C., a film for processing a wafer having an acrylic pressure-sensitive adhesive layer having a coating thickness of 20 μm was obtained.

The wafer processing film thus obtained was attached to a mirror wafer, left for 24 hours, and then the film was peeled off.
The contamination degree on the wafer surface and the number of foreign particles on the wafer surface were measured. Further, 1 g of an adhesive was dropped on glass to form a film, immersed in water, and the time until whitening was measured. The results are shown in Table 1.

Example 2 The same method as in Example 1 except that 0.5 parts by weight of a compound obtained by adding an allyl group to a benzene ring of ammonium salt of polyoxyethylene nonyl phenyl ether sulfate (ethylene oxide 10 mol) was used as a surfactant. The film for processing a wafer obtained by carrying out in
Was evaluated in the same manner as described above. The results are shown in Table 1.

Example 3 Example 2 except that the amount of surfactant added was 0.05 parts by weight.
The wafer processing film obtained by the same method as in Example 1 was evaluated by the same method as in Example 1. The results are shown in Table 1.

Example 4 Example 1 except that 10 parts by weight of the surfactant was used.
The wafer processing film obtained by the same method as in Example 1 was evaluated by the same method as in Example 1. The results are shown in Table 1.

Example 5 The surfactant was sodium salt of polyoxyethylene nonylphenyl ether sulfate (ethylene oxide).
Except for the compound having an allyl group added to the benzene ring (10 mol), a film for processing a wafer obtained in the same manner as in Example 2 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6 A wafer processed by the same method as in Example 2 except that the surfactant is a compound obtained by adding a sodium sulfate to a compound obtained by adding a higher alcohol and an allyl group to maleic acid. The film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7 The surfactant was potassium salt of polyoxyethylene nonyl phenyl ether sulfate (ethylene oxide 10
(Mol), a wafer processing film obtained by the same method as in Example 2 except that the compound had an allyl group added to the benzene ring was evaluated by the same method as in Example 1. The results are shown in Table 1.

Comparative Example 1 A film for processing a wafer obtained by the same method as in Example 1 except that 2.0 parts by weight of polyoxyethylene nonylphenyl ether (ethylene oxide 50 mol) was used as a surfactant, Evaluation was performed in the same manner. The results are shown in Table 1.

Comparative Example 2 A wafer processing film obtained in the same manner as in Example 1 except that 5.0 parts by weight of polyoxyethylene nonyl phenyl ether (ethylene oxide 50 mol) was used as a surfactant, Evaluation was performed in the same manner. The results are shown in Table 1.

Comparative Example 3 A wafer processing film obtained in the same manner as in Example 1 except that 0.5 parts by weight of ammonium salt of polyoxyethylene nonylphenyl ether sulfate (ethylene oxide 10 mol) was used as a surfactant. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 A wafer processing film obtained in the same manner as in Example 1 except that 0.05 parts by weight of ammonium salt of polyoxyethylene nonylphenyl ether sulfate (ethylene oxide 10 mol) was used as a surfactant. To
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 5 A wafer processing film obtained in the same manner as in Example 1 except that 0.5 parts by weight of sodium salt of polyoxyethylene nonylphenyl ether sulfate (ethylene oxide 10 mol) was used as a surfactant. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 6 An adhesive was obtained in the same manner as in Example 1, except that 2.0 parts by weight of polyoxyethylene nonylphenyl ether (ethylene oxide 50 mol) was used as a surfactant.

Next, 10 parts by weight of diethylene glycol monobutyl ether and 2.0 parts by weight of polyoxyethylene nonylphenyl ether (50 moles of ethylene oxide) were added to 100 parts by weight of this adhesive.
A coating solution was prepared by adding parts by weight, and applied to a corona-treated one surface of an ethylene-vinyl acetate copolymer film having a thickness of 150 μm by a roll coater, and dried at 105 ° C. to obtain a coating thickness of 2
A film for wafer processing having an acrylic pressure-sensitive adhesive layer of 0 μm was obtained.

The obtained wafer processing film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 7 Using the same apparatus as in Example 1, under the same conditions as in Example 1, 80 parts by weight of butyl acrylate, 15 parts by weight of acrylonitrile, 5 parts by weight of acrylic acid, and 200 parts by weight of ethyl acetate were subjected to benzoyl peroxide. The solution was polymerized using 1 part by weight to obtain an adhesive.

Next, 10 parts by weight of a melamine-based cross-linking agent and 1.0 part by weight of polyethylene glycol oleyl ether of HLB15 were added to 100 parts by weight of the adhesive to prepare a coating solution, and a 150 μm-thick ethylene-vinyl acetate copolymer film was prepared. One surface of the corona-treated film was coated with a roll coater and dried at 105 ° C. to obtain a film for wafer processing having an acrylic pressure-sensitive adhesive layer having a coating thickness of 20 μm.

The obtained wafer processing film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 8 The wafer processing film used in Comparative Example 1 was attached to a mirror wafer, left for 24 hours, and then peeled off.
After cleaning the wafer surface with pure water, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Reference Example 1 The degree of contamination on the wafer surface of the mirror wafer and the number of foreign particles on the wafer surface were measured.

〔The invention's effect〕

The wafer processing film of the present invention exhibits an excellent effect of not contaminating the wafer by using an adhesive using a reactive surfactant as a surfactant during polymerization.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/304 C09J 7/02

Claims (3)

(57) [Claims] 1. A wafer processing film having a pressure-sensitive adhesive layer provided on one side of a base film, wherein an aqueous emulsion pressure-sensitive adhesive using a reactive surfactant is used as a surfactant during polymerization of the pressure-sensitive adhesive. Characteristic film for wafer processing. 2. The wafer processing film according to claim 1, wherein the amount of the reactive surfactant added during the polymerization of the pressure-sensitive adhesive is 0.05 to 10.0 parts by weight based on 100 parts by weight of the polymerized monomer. 3. The wafer processing film according to claim 1, wherein the reactive surfactant is a nonionic surfactant or an anionic surfactant which is an ammonium salt.