JP2008244377A - Sheet and adhesive tape for processing semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin adhesive tape excellent in anti-static property for processing semiconductor wafer with less scraps produced during dicing. <P>SOLUTION: The sheet used as a base of adhesive tape for processing a semiconductor wafer contains high molecular type anti-static agent of 5-30 wt.%, polyolefin based resin of 30-85 wt.%, and rubber-state elastic body of 10-40 wt.%. In the polyolefin based adhesive tape for processing the semiconductor wafer, this sheet is used as a base and an adhesion layer is applied to one face of the sheet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet and an adhesive tape for processing a semiconductor wafer.

  In the process of manufacturing a semiconductor device, an adhesive tape for processing a semiconductor wafer is used when cutting a semiconductor wafer, a package, or the like. This adhesive tape is used for picking up semiconductor elements obtained by affixing, dicing, expanding, etc. on a semiconductor wafer, package, etc., and cutting the semiconductor wafer, package, etc.

Such an adhesive tape is comprised by the base material sheet and the adhesive layer provided in the single side | surface of the base material sheet.
As the base sheet, a polyvinyl chloride (PVC) resin sheet has been mainly used. However, due to environmental problems with the use of PVC resins and the possibility of contamination of semiconductor elements due to bleeding of additives such as plasticizers used in PVC resins, recently, polypropylene sheets, ethylene vinyl alcohol sheets and ethylene methacrylic acid have been used. A base sheet using a polyolefin-based material such as an acrylate-based sheet has been developed (see, for example, Patent Document 1).

  In recent years, miniaturization and thinning of semiconductor elements have progressed, and the problem of device destruction due to static electricity, which has not been a problem until now, has become apparent. In particular, there is a problem of adhesion of chips (whisker-like cut residue extending from the cut line of the base material sheet) to the device in an ethylene vinyl alcohol sheet or ethylene methacrylate acrylate sheet. Therefore, in the adhesive tape for semiconductor wafer processing, there is an increasing demand for a polyolefin-based sheet having excellent antistatic performance and less generation of chips.

JP 09-008111 A

  An object of the present invention is to provide a polyolefin-based sheet having excellent antistatic properties and less generation of chips during dicing and an adhesive tape for processing a polyolefin-based semiconductor wafer using the same as a base sheet.

The present invention
(1) A sheet used as a base material for an adhesive tape for processing a semiconductor wafer, wherein the polymer type antistatic agent is 5 to 30% by weight, the polyolefin resin is 30 to 85% by weight, and the rubber-like elastic body is 10 to 40%. % By weight, sheet characterized by inclusion,
(2) The sheet according to item (1), wherein the polymer antistatic agent is an ion conductive antistatic agent;
(3) The sheet according to (1) or (2), wherein the polymer-type antistatic agent has a polyether polyolefin copolymer as a main component,
(4) The sheet according to any one of (1) to (3), wherein the polyolefin resin is a homopolypropylene resin,
(5) Forcibly charged to 5000 V in the MD direction of the sheet in an environment of 23 ° C.-50% RH, and thereafter the time for the charged voltage to decay to 0 V is 0.5 seconds or less (1) to (4) ) The sheet according to any one of items
(6) An adhesive tape for processing a semiconductor wafer, wherein an adhesive layer is provided on one side of the sheet according to any one of (1) to (5),
It is.

  According to the present invention, by using the obtained polyolefin-based sheet as a base material, it is possible to provide a pressure-sensitive adhesive tape for processing semiconductor wafers that has excellent antistatic properties and generates less chips during dicing.

 Hereinafter, the present invention will be described in more detail. The present invention relates to a polyolefin-based sheet used as a base material for an adhesive tape for processing a semiconductor wafer, in which a polymer-type antistatic agent is 5 to 30% by weight, a polyolefin-based resin is 30 to 85% by weight, and a rubber-like elastic body is The sheet is characterized by being contained in an amount of 10 to 40% by weight.

A typical low molecular weight antistatic agent having an antistatic property by imparting a polar group such as a hydroxyl group to the surface of the sheet base material and bonding with moisture in the air by being embedded in the sheet base material is low. A polymer type antistatic agent can be preferably used because there is a problem in that the performance under humidity is deteriorated or the antistatic property is deteriorated due to bleeding out of the antistatic component or washing with water.
Examples of the polymer antistatic agent include polyether ester amide and polyether / polyolefin block polymer.
Among these, an ion conductive antistatic agent using a polyether polyolefin copolymer can be particularly preferably used.
The ionic conduction type antistatic agent using the polyether polyolefin copolymer has a conductive mechanism by the polyether part and the ionic part and has an antistatic property, and the olefin part copolymerized with the polyether part allows other polyolefins to be used. Excellent kneadability with resin.

  The compounding amount of the polymer type antistatic agent is 5 to 30% by weight, preferably 10 to 20% by weight. If the compounding amount of the polymer type antistatic agent is less than the lower limit value, sufficient antistatic performance of the base sheet cannot be obtained, and if it exceeds the upper limit value, the amount of chip of the base sheet increases or the sheeting property of the base sheet Cause a decline.

  As the polyolefin resin, a polypropylene resin is particularly preferable from the viewpoint of mechanical strength. Furthermore, among polypropylene resins, homopolypropylene resins are less likely to generate chips during adhesive tape dicing.

  The compounding quantity of polyolefin resin is 30 to 85 weight%, Preferably it is 40 to 60 weight%. When the blending amount of the polyolefin resin is less than the lower limit value, sufficient mechanical strength cannot be obtained, and when the upper limit value is exceeded, the expandability is deteriorated.

 Rubber-like elastic bodies are natural and synthetic polymer resins that exhibit elasticity at room temperature. The rubber-like elastic body in the sheet used as the base material of the semiconductor wafer processing adhesive tape is not particularly defined, but heat such as styrene butadiene copolymer resin or styrene isoprene copolymer resin mainly composed of butadiene or isoprene. A plastic elastomer is preferred. Moreover, in order to improve heat resistance and weather resistance, you may use what hydrogenated the double bond part. The more the rubber component in the rubber-like elastic body, the better the resilience is. However, problems such as the rubber-like elastic body blocking and difficult to handle occur, so the rubber component content in the rubber-like elastic body is 50 to 50%. 95% by weight is preferred. Moreover, you may use the rubber-like elastic body which added the blocking inhibitor.

 The compounding amount of the rubber-like elastic body is 10 to 40% by weight, preferably 20 to 30% by weight. If the blending amount is less than the lower limit, the expandability of the base sheet is lowered. Moreover, when the upper limit is exceeded, chips of the base sheet increase and sheeting properties of the base sheet deteriorate.

  In a 23 ° C.-50% RH environment, the sheet is forcibly charged to 5000 V in the MD direction and then decays to a charged voltage of 0 V for 0.5 seconds or less, preferably 0.1 seconds or less, more preferably 0. .05 seconds or less. If the decay time exceeds 0.5 seconds, the antistatic property is deteriorated, and there is a risk of destruction of the device or adhesion of dust due to the generated static electricity.

  Various resins, additives, and the like can be added to the sheet in accordance with the purpose as long as the characteristics are not impaired.

  When using the adhesive tape for semiconductor wafer processing which used the sheet | seat of this invention as the base material layer, it is necessary to provide an adhesive layer to the single side | surface of a base material layer. The adhesive layer is not particularly defined here, but characteristics such as adhesive strength can be selected according to the purpose.

  Regarding the generation of chips (beard cut residue extending from the cut line of the base sheet), it tends to increase and become worse when an antistatic agent and a rubber-like elastic body are added. However, antistatic properties are necessary to prevent wafer breakage, etc., and rubbery elastic is used to prevent loosening of the adhesive tape when storing the adhesive tape after the expansion process or picking up the device. The body is essential. Therefore, by using polyolefin-based resins, especially propylene-based resins, and among them, homopolypropylene resins, it is excellent in antistatic properties and generates less chips, and an adhesive tape for processing semiconductor wafers using the same. Can be provided. In addition, it is from a base material sheet, and it does not generate | occur | produce from a base material, although the chip which becomes a problem (beard-like cutting residue extended from the cut line of the base material sheet) generate | occur | produces.

  The substrate sheet thickness when used as a dicing tape is 30 to 300 μm, preferably 50 to 200 μm, more preferably 70 to 150 μm. Moreover, as thickness of the adhesion layer, it is 3-50 micrometers, Preferably, it is 5-30 micrometers, More preferably, it is 5-20 micrometers.

The present invention will be described in more detail by way of examples, but this is merely an example, and the present invention is not limited thereby.
<Preparation of base sheet>
The following raw materials were used at the compounding ratios shown in Table 1 to obtain a sheet having a thickness of 100 μm.
・ Polymer type antistatic agent Polymer type antistatic agent 1 Pelestat 230 (manufactured by Sanyo Chemical Industries, Ltd.)
Polymeric antistatic agent 2 Sanconol TBX-310 (manufactured by Sanko Chemical Co., Ltd.)
・ Polyolefin resin Homopolypropylene 1 Nobrene FS2016 (manufactured by Sumitomo Chemical Co., Ltd.)
(MFR: 2.1 g / 10 min Tensile modulus: 1300 MPa)
Homo polypropylene 2 Novatec EA7A (Nippon Polypro Co., Ltd.)
(MFR: 1.4 g / 10 min Tensile modulus: 1500 MPa)
Homo polypropylene 3 Novatec SA4L (Nippon Polypro Co., Ltd.)
(MFR: 5.3 g / 10 min Tensile modulus: 2050 MPa)
Random polypropylene Prime polypro F327 (manufactured by Prime Polymer Co., Ltd.)
(MFR: 7.0 g / 10 min Tensile elastic modulus: 850 MPa)
Block polypropylene Sun Allomer PB270A (manufactured by Sun Allomer Co., Ltd.)
(MFR: 0.7 g / 10 min Tensile modulus: 950 MPa)
Low density polyethylene Sumikasen F238-1 (manufactured by Sumitomo Chemical Co., Ltd.)
(MFR: 2.0 g / 10 min Tensile modulus: 200 MPa)
Linear low density polyethylene Sumikasen EFV202 (manufactured by Sumitomo Chemical Co., Ltd.)
(MFR: 1.9 g / 10 min Tensile modulus: 310 MPa)
・ Rubber elastic body Styrene isoprene copolymer Hibler 7125 (manufactured by Kuraray Co., Ltd.)
Styrene butadiene copolymer Toughprene 125 (manufactured by Asahi Kasei Chemicals Corporation)
Styrene ethylene propylene copolymer Septon 2007 (manufactured by Kuraray Co., Ltd.)
Olefin-based thermoplastic elastomer XELAS 7053 (Mitsubishi Chemical Corporation)

<Preparation of adhesive layer>
A base resin having a weight average molecular weight of 150,000 was obtained by solution polymerization of 30% by weight of 2-ethylhexyl acrylate, 70% by weight of vinyl acetate and 1% by weight of 2-hydroxyethyl methacrylate in a toluene solvent.
Addition of 100 parts by weight of bifunctional urethane acrylate as an energy ray curable resin (Mitsubishi Rayon Co., Ltd., weight average molecular weight of 11,000) and addition of polyhydric alcohol of tolylene diisocyanate as a crosslinking agent to 100 parts by weight of this base resin 15 parts by weight of a body (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and 5 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as an energy ray polymerization initiator were dissolved in ethyl acetate, and then a release-treated polyester film (thickness) The thickness after drying was 10 μm and dried at 80 ° C. for 5 minutes to obtain an adhesive layer.

<Production of adhesive tape>
The above-mentioned adhesive layer was laminated on a sheet having a thickness of 100 μm obtained at a blending ratio shown in Table 1 using a laminate roll at 30 ° C. to obtain an adhesive tape for semiconductor wafer processing.

The obtained adhesive tape was evaluated on the following items.
<1> Chip dicing conditions Dicing blade: NBC-ZH2050-SE 27HEDD (manufactured by DISCO Corporation)
Blade rotation speed: 40000 rpm
Cutting speed: 100mm / sec
Blade height: 60μ
Blade cooler: 2L / min
The adhesive tape for semiconductor wafer processing with the silicon mirror wafer attached (mirror surface attachment) was allowed to stand for 20 minutes after wafer attachment, and was diced to 5 mm □ under the above dicing conditions. The tape after dicing was irradiated with UV, the wafer was peeled off, and the cut line was observed with a microscope. Chips on each side of an arbitrary adjacent 10 chip (5 × 2) dicing line were observed. When the maximum length of the chips is 15 μm or less, “◎”, when 15 μm to 30 μm, “◯”, when 30-50 μm, “Δ”, and when longer than 50 μm, “×”. And the thing of the length of the chip of 50 micrometers or less was considered as the pass.

<2> Decay time Using STATIC DECAY METER MODEL 406C (manufactured by electro-tech systems, Inc.), the charge decay time was measured in an environment of 23 ° C. to 50% RH. Set in the machine so that voltage is applied in the MD direction of the adhesive tape, forcibly charge to 5000V, and then measure the time for the charged voltage to decay to 0V. Those having a second to 0.1 seconds were marked with ◯, those having a time between 0.1 seconds and 0.5 seconds were marked with Δ, and those having a time longer than 0.5 seconds were marked with ×. And the thing whose decay time was 0.5 second or less was made into the pass.

<3> Expandability Adhesive tape for semiconductor wafer processing is affixed to a 6-inch ring, and when the expander MODEL HS-1010 / 190 (manufactured by Hugle Electronics Co., Ltd.) is expanded 20 mm, the tape is not torn and the tape is torn. The thing was made into x.

  By using the polyolefin-based sheet of the present invention as a base material, it is possible to provide a pressure-sensitive adhesive tape for processing a polyolefin-based semiconductor wafer that has excellent antistatic properties and generates less chips.

Claims (6)

  A sheet used as a base material for an adhesive tape for processing a semiconductor wafer, wherein the polymer antistatic agent is 5 to 30% by weight, the polyolefin resin is 30 to 85% by weight, the rubbery elastic body is 10 to 40% by weight, A sheet characterized by being included.   The sheet according to claim 1, wherein the polymer type antistatic agent is an ion conduction type antistatic agent. The sheet according to claim 1 or 2, wherein the polymer-type antistatic agent has a polyether polyolefin copolymer as a main component.   The sheet according to any one of claims 1 to 3, wherein the polyolefin resin is a homopolypropylene resin.   5. The time when the charged voltage is forcibly charged to 5000 V in the MD direction of the sheet in an environment of 23 ° C.-50% RH and thereafter the voltage is attenuated to 0 V is 0.5 seconds or less. 6. Sheet.   A pressure-sensitive adhesive tape for processing a semiconductor wafer, wherein a pressure-sensitive adhesive layer is provided on one side of the sheet according to claim 1.