JP2006036834A - Adhesive tape for processing semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive tape for processing semiconductor wafers which involves only a small transfer of an adhesive (remaining adhesive) to the tip at the time of pickup. <P>SOLUTION: The adhesive tape for processing semiconductor wafers is prepared by coating an adhesive comprising a base resin, a radiation polymerizable compound, a radiation polymerization initiator and a crosslinking agent on the surface of a soft polyvinyl chloride resin film substrate having permeability to ultraviolet rays and/or electron beams, wherein the surface of the soft polyvinyl chloride resin film to be coated with the adhesive is subjected to plasma treatment, and the surface has a wetting index as defined by JIS K6768 of 40 mN/m or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive tape for processing a semiconductor wafer used when processing a semiconductor wafer such as silicon or gallium arsenide.

  Conventionally, as an adhesive tape for processing semiconductor wafers used for pasting, pasting, dicing, expanding, etc. on a semiconductor wafer, then picking up the chip from the semiconductor wafer and mounting it, it is permeable to ultraviolet rays and / or electron beams A pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer that undergoes a polymerization and curing reaction with ultraviolet rays and / or an electron beam is applied onto a substrate having UV light, and after the dicing, the pressure-sensitive adhesive layer is irradiated with ultraviolet rays and / or electron beams. A method is known in which a chip is picked up by causing a polymerization and curing reaction to reduce the adhesive force.

  In recent years, with the progress of miniaturization and high performance of electronic devices, it is required to expand the distance between chips by expanding and to easily pick up. Usually, 5 to 10% expand is common, but 20 to 40% expand may occur. At this time, when the base material does not follow the expansion of the expand, there is a problem that the chip interval after the expansion is not opened.

  For this reason, as disclosed in Patent Documents 1 and 2, as a resin film substrate corresponding to the expand, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, A single layer or laminated sheet of polyurethane, ethylene vinyl acetate copolymer, ionomer, ethylene / (meth) acrylic acid copolymer, or ethylene / (meth) acrylic acid ester copolymer has been used.

Among them, a film made of a soft vinyl chloride resin is particularly well stretched when expanded and used to widen the chip interval. However, when expanded, there is a problem in the adhesion between the base material and the adhesive, and the adhesive is difficult when picked up. There was a problem that the adhesive peeled off from the base material and the adhesive was transferred to the chip (adhesive residue).
In general, in order to increase the adhesion with the base material, the wettability index defined in JISK6768 is increased and improved by performing corona treatment or electron beam irradiation on the base material as described in Patent Documents 3 to 4. May be seen.
However, in the case of soft vinyl chloride resin, there was no change in the wetting index defined by JISK6768 before and after treatment, and no effect was seen. Therefore, in the case of soft vinyl chloride resin, there has been a demand for a tape that does not peel off the adhesive from the base material during expansion, and has no adhesive remaining during pickup.

JP-A-3-66772 JP 2001-72947 A JP-A-1-49754 Japanese Patent Laid-Open No. 5-21234

  An object of the present invention is to provide a pressure-sensitive adhesive tape for processing a semiconductor wafer with little transfer (adhesive residue) of the pressure-sensitive adhesive to the chip during pick-up.

  The present invention provides a pressure-sensitive adhesive comprising a base resin, a radiation-polymerizable compound, a radiation-polymerizable polymerization initiator, and a cross-linking agent on the surface of a soft vinyl chloride resin film substrate having transparency to ultraviolet rays and / or electron beams. An adhesive tape for processing semiconductor wafers, which is applied to a surface of a soft vinyl chloride resin film to which an adhesive is applied, and the wetting index of the film surface defined by JIS K6768 is 40 mN / m or more. A pressure-sensitive adhesive tape for processing semiconductor wafers.

  The adhesive tape for processing a semiconductor wafer according to the present invention reduces the transfer (adhesive residue) of the adhesive to the chip after pickup. As a result, the adhesion between the chip and the substrate is improved, the yield is improved, and the reliability of the semiconductor product composed of the chips is improved.

Hereinafter, the present invention will be described in detail.
The resin used for the soft vinyl chloride resin film substrate of the present invention refers to all polymers having a group represented by CH ₂ -CHCl, such as a vinyl chloride homopolymer and an ethylene-vinyl chloride copolymer. Copolymers of vinyl chloride and polymerizable monomers, chlorinated vinyl chloride copolymers, etc., and modified copolymers, and chlorination similar to vinyl chloride resins in structure such as chlorinated polyethylene Includes polyethylene. These vinyl chloride resins preferably have a number average degree of polymerization of 300 to 3000, and more preferably 500 to 2000. These vinyl chloride resins can be used alone or in combination of two or more.

  The stabilizer of the soft vinyl chloride resin used in the present invention is not particularly specified, but any stabilizer may be used as long as it is used as a stabilizer for ordinary soft vinyl chloride resins. For example, a lead type, a barium-zinc type, a calcium-zinc type, a tin type, etc. are mentioned. The addition amount of the stabilizer is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. When the added amount of the stabilizer is less than 1 part by weight, the effect of the soft vinyl chloride resin as a stabilizer is small, and when it exceeds 10 parts by weight, there is a problem of bloom or choking.

Examples of the plasticizer of the soft vinyl chloride resin that is the base material of the present invention include phthalates such as DOP, n-DOP, DINP, and DIDP mixed alkyl phthalate, and fragrances such as trioctyl trimellitate and trioctyl pyromellitate. Aliphatic carboxylic acid esters, fatty acid dibasic esters such as DOA, DOZ, DOS, epoxy soybean oil, epoxidized linseed oil, chlorinated paraffin, polyester, etc. Can be used in combination.
The addition amount of the plasticizer is 20 to 45 parts by weight, preferably 25 to 40 parts by weight, and more preferably 30 to 38 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. When the amount of the plasticizer exceeds 45 parts by weight, the plasticizer migrates to the pressure-sensitive adhesive layer, which causes a decrease in adhesive strength, which is not preferable.

  The soft vinyl chloride resin that is the base material of the present invention may contain a lubricant, a colorant, and the like that are generally blended in this type of resin composition. Although these additions are optional, it is necessary to make this film transparent when ultraviolet rays are used as the irradiation radiation of the film, so these should not significantly impair the transparency of the film. Don't be.

  As a method for producing the soft vinyl chloride resin composition of the present invention, a general method used for producing ordinary resin compositions and rubber compositions can be employed. Basically, it is a mechanical melt kneading method, and for these, a single screw extruder, a twin screw extruder, a Banbury mixer, various kneaders, a brabender, a roll or the like is used. At this time, there is no restriction on the order of adding each component. In this case, the melt kneading temperature can be suitably selected from 140 ° C to 200 ° C.

  The soft vinyl chloride resin film substrate used in the present invention is produced by molding the above-described vinyl chloride resin composition, and this may be performed by general molding methods such as extrusion molding, calendar molding, and inflation molding. . The thickness of the film thus produced is preferably in the range of 50 to 300 mm.

  Or you may add a pigment, an antistatic agent, antioxidant, etc. to such an extent that the physical property of these base materials and a chip | tip back surface are not affected.

The plasma treatment performed in the present invention is not particularly specified by a method or the like, but the processing gas includes oxygen gas, argon gas, nitrogen gas, etc., but nitrogen gas is preferred. The reason for using nitrogen gas is that the N ₃ radical generated by the plasma breaks the C—C bond in the PVC base material and is released into the air after the plasma treatment, or oxygen in the air or the PVC base material. It reacts with oxygen (O ₂ ) contained therein, and C—OH. There is an effect of attaching a C-OOH group.
The wetting index specified by JIS K6768 of the soft PVC film before the plasma treatment is 30 to 35 mN / m, but the wetting index specified by JIS K6768 of the surface of the plasma treated is 40 mN / m or more. If it exists, the adhesive force with an adhesive will rise and an adhesive will not peel at the time of pick-up.

  By performing the plasma treatment, the physical properties other than the wetting index defined in JIS K6768 of the base material are not changed, and it can be handled in the same manner as a normal soft vinyl chloride film.

  When the corona treatment and electron beam irradiation treatment shown in Reference 3.4 are performed and the wetting index specified by JIS K6768 is increased, the surface modified by the treatment tries to return to the state before the treatment, and the room temperature is 6 months. When the product is stored for a long period of time, the wetting index specified in JIS K6768 may return to the state of the wetting index before processing. In the present invention, even when stored at room temperature for 6 months, There is no change in the prescribed wetting index.

  The radiation-polymerizable compound used in the present invention has a sufficient adhesive force to the semiconductor wafer before the curing reaction with ultraviolet rays and / or electron beams, and the adhesive force is reduced after the curing reaction, so that the chip can be easily picked up. In order to maintain a high cohesive force, a bifunctional urethane acrylate having a molecular weight of 5000 or more, preferably 8000 or more, more preferably 10,000 or more and a pentafunctional or more acrylate having a molecular weight of 500 or more and 1000 or less. It may be a mixture of monomers. Moreover, the pentafunctional or higher acrylate monomer having a molecular weight of 500 or more and 1000 or less may be used in combination of two types of pentafunctional or higher acrylate monomers.

The bifunctional urethane acrylate in the radiation-polymerizable compound used in the present invention is a compound synthesized with diisocyanate, polyol and hydroxy (meth) acrylate, and preferably urethane acrylate having two acryloyl groups. Used. Examples of the diisocyanate include toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, dicyclohexylmethane diisocyanate, xylene diisocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate. Examples of the polyol include ethylene glycol, propylene glycol, butanediol, hexanediol and the like. Examples of the hydroxy (meth) acrylate include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate.
Examples of the pentafunctional or higher acrylate monomer in the radiation-polymerizable compound include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and the like. Can do.

  Examples of the radiation-polymerizable polymerization initiator include 2-2-dimethoxy-1,2-diphenylethane-1-one, benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, Tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone and the like can be mentioned.

  Specific examples of the crosslinking agent include polyisocyanate polyisocyanate compounds and polyisocyanate compound trimers, terminal isocyanate compound trimers obtained by reacting the above polyisocyanate compounds and polyol compounds, and terminal isocyanate urethane prepolymers. Examples thereof include blocked polyisocyanate compounds in which a polymer is blocked with phenol, oximes or the like.

  Specific examples of the polyvalent isocyanate include, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4-4′-diisocyanate. , Diphenylmethane-2-4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4-4'-diisocyanate, dicyclohexylmethane-2-4'-diisocyanate, lysine isocyanate, etc. can give. Moreover, what added polyhydric alcohol to those isocyanate may be used.

  The pressure-sensitive adhesive of the present invention includes a rosin resin, a terpene resin, a coumarone resin, a phenol resin, a styrene resin, an aliphatic petroleum resin, an aromatic petroleum resin, and an aliphatic aromatic copolymer petroleum to increase the cohesive force. You may add tackifiers, such as resin.

  Furthermore, an antistatic agent can be added to the above-mentioned pressure-sensitive adhesive. By adding an antistatic agent, static electricity generated at the time of expanding or picking up can be suppressed, so that the reliability of the chip may be improved. Specific examples of the antistatic agent include anionic, cationic, nonionic, and amphoteric surfactants, carbon black, silver, nickel, antimony-doped tin oxide, tin-doped indium oxide. Such powder is used. The antistatic agent is preferably used in the pressure-sensitive adhesive in the range of 0 to 30 parts by weight, particularly 0 to 20 parts by weight.

In the present invention, the thickness of the pressure-sensitive adhesive layer is 5 to 30 μm, preferably 10 to 20 μm. If the thickness is less than the lower limit, there is a problem that the adhesive force is not sufficient and the chips are scattered during dicing, and if the thickness exceeds the upper limit, it becomes difficult to pick up the chips.
In the present invention, in order to produce the pressure-sensitive adhesive layer on the substrate and produce a pressure-sensitive adhesive tape for processing a semiconductor wafer, the components constituting the pressure-sensitive adhesive layer are dissolved as they are or with an appropriate organic solvent, and then a comma coater , A gravure coater, a die coater, a reverse coater, etc., which are coated on a substrate by coating or spraying to an appropriate thickness according to a generally known method, and dried by, for example, heat treatment at 80 to 100 ° C. for about 30 seconds to 10 minutes. Can be obtained.

  In order to use the semiconductor wafer processing adhesive tape of the present invention, a known method can be used. For example, after adhering the semiconductor wafer processing adhesive tape to the semiconductor wafer and fixing it, the semiconductor wafer is formed into a chip with a rotating round blade. Disconnect. Then, after irradiating ultraviolet rays and / or an electron beam from the substrate side of the processing adhesive tape, and then expanding the wafer processing adhesive tape radially using a dedicated jig to spread the chips at regular intervals. Is picked up by a method such as suction with a vacuum collet, air tweezers, etc.

Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these.
Example 1
10 parts by weight of copolymer (A) having a weight average molecular weight of 500,000 obtained by copolymerization of 70 parts by weight of butyl acrylate and 30 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of 2-ethylhexyl acrylate and vinyl acetate Bifunctional urethane acrylate (C) having a molecular weight of 11,000 as a radiation polymerization compound with respect to 100 parts by weight of a base resin comprising 90 parts by weight of a copolymer (B) having a weight average molecular weight of 300,000 obtained by copolymerization with 70 parts by weight ), 30 parts by weight of pentafunctional acrylate monomer (D) having a molecular weight of 700, 5 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as a radiation-polymerizable polymerization initiator (E), polyisocyanate type A 38 μm-thick polyester film obtained by subjecting a resin solution to be an adhesive layer containing 6 parts by weight of a crosslinking agent (F) to a release treatment The thickness after drying Tel film coated as (adhesive thickness) is 10 [mu] m, and dried 80 ° C. 5 min.
A soft vinyl chloride resin film (Mitsubishi Chemical MKV Altron) with a thickness of 80 μm, which had been plasma-treated in nitrogen gas for 1 second (wetting index: 50 mN / m), was laminated to produce an adhesive tape for semiconductor processing.

Example 2 A sample was prepared and evaluated in the same manner as in Example 1 except that a soft vinyl chloride resin film (wet index: 42 mN / m) plasma-treated in nitrogen gas for 0.3 seconds was laminated. .
Example 3 A sample was prepared and evaluated in the same manner as in Example 1 except that a soft vinyl chloride resin film (wetting index: 60 mN / m) that was plasma-treated in nitrogen gas for 2 seconds was laminated.
Comparative Example 1 A sample was prepared and evaluated in the same manner as in Example 1 except that a soft vinyl chloride resin film (wetting index: 32 mN / m) not subjected to plasma treatment was laminated.
Comparative Example 2 A sample was prepared in the same manner as in Example 1 except that a soft vinyl chloride resin film (wetting index: 32 mN / m) subjected to corona treatment at a current of 8 A and a line speed of 6 m / min was laminated. evaluated.
Comparative Example 3 A sample was prepared and evaluated in the same manner as in Example 1 except that a soft vinyl chloride resin film (wetting index: 32 mN / m) subjected to an electron beam irradiation treatment at 100 kGy was laminated.
Comparative Example 4 A sample was prepared and evaluated in the same manner as in Example 1 except that a soft vinyl chloride resin film (wetting index: 36 mN / m) plasma-treated in nitrogen gas for 0.1 seconds was laminated. .

In addition, evaluation of Examples 1-3 and Comparative Examples 1-4 performed the presence or absence of the transcription | transfer of an adhesive according to JISK5400. The evaluation criteria are as follows.
○: Adhesive is not peeled off (no transfer of adhesive)
X: The adhesive is peeled off from the substrate (there is an adhesive transfer)
The above results are summarized in Table 1.

  According to the present invention, there is no limit on the amount of expand when processing a semiconductor wafer, and there is excellent processability in that the chip interval can be widened, and the adhesion force between the substrate and the adhesive is on the chip and the adhesive. Compared with this, an adhesive tape for processing a semiconductor wafer with little adhesive residue at the time of pick-up can be obtained, so that it can be suitably used for dicing electronic components such as IC chips and discretes.

Claims (1)

  An adhesive composed of a base resin, a radiation-polymerizable compound, a radiation-polymerizable polymerization initiator, and a cross-linking agent is applied on the surface of a soft vinyl chloride resin film substrate that is transparent to ultraviolet rays and / or electron beams. A pressure-sensitive adhesive tape for processing semiconductor wafers, characterized in that a soft vinyl chloride resin film surface to which an adhesive is applied is subjected to plasma treatment, and the wetting index of the film surface defined by JIS K6768 is 40 mN / m or more. Adhesive tape for semiconductor wafer processing.