JP3701881B2 - Cleaning sheet and method for cleaning substrate processing apparatus using the same - Google Patents

Description

【００２９】
上記の結果より、クリーニング層のセパレータ（保護フィルム）として、熱劣化防止剤と滑剤との合計量がポリエチレン系樹脂１００部に対して０．０１部未満となるクリーニング層保護フィルムを用いた実施例１，２のクリーニングシートは、クリーニング層面に対する剥離力が０．５Ｎ／５０ｍｍ幅以下と小さく、クリーニング層組成の一部脱落などの支障をきたさずに容易に剥離できた。しかもシリコンウェハへの付着異物数が少ないため、これらクリーニングウェハを用いれば基板処理装置への汚染を大幅に低減でき、高い異物除去性をもつことがわかった。これに対して、上記の合計量が本発明の範囲外となる比較例１、２のクリーニングシートや従来のシリコーン処理されたポリエステルフィルムを用いた比較例３のクリーニングシートでは、シリコンウェハへの付着異物が多く、その結果これらクリーニングウェハを用いると装置への逆汚染が生じてしまうことで異物除去性が悪く、利用できないことがわかった。
【００３０】
【発明の効果】
以上のように、本発明では、クリーニングシートのクリーニング層表面保護フィルム（セパレータ）を、離型処理を施さないポリオレフィン系樹脂で構成し、かつこれに含まれる熱劣化防止剤と滑剤との量を特定値以下に抑えたことにより、基板処理装置内の搬送部位などの付着異物の除去方法に適用し、保護フィルムに起因した装置への汚染の問題を回避でき、高い異物除去性を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet for cleaning an apparatus, for example, a cleaning sheet and a cleaning method for a substrate processing apparatus that dislikes foreign matters such as a semiconductor or flat panel display manufacturing apparatus and a semiconductor or flat panel display inspection apparatus.
[0002]
[Prior art]
The substrate processing apparatus transports each transport system and the substrate in physical contact. At this time, if foreign substances adhere to the substrate or the transport system, subsequent substrates are contaminated one after another, and it is necessary to periodically stop the apparatus and perform a cleaning process. For this reason, there existed a problem that an operation rate fall and a great effort were required. In order to solve these problems, a method of cleaning and removing adhered foreign substances in the substrate processing apparatus by conveying a substrate to which an adhesive substance is fixed (Japanese Patent Laid-Open No. 10-154686) or a plate-like member is conveyed. A method (Japanese Patent Laid-Open No. 11-87458) for removing foreign substances adhering to the back surface of the substrate has been proposed.
[0003]
[Problems to be solved by the invention]
The method of cleaning and removing the adhered foreign matter in the substrate processing apparatus by transporting the substrate to which the adhesive substance is fixed is an effective method for overcoming the above-described problems. However, in this method, since an adhesive substance is used as the cleaning layer, there is a fear that the substrate contact portion is too strongly adhered and cannot be peeled off, and the substrate cannot be reliably conveyed. This is particularly a problem when a vacuum suction mechanism is used for the chuck table of the apparatus.
Moreover, although the method of removing a foreign material by conveying a plate-like member can perform the conveyance without any problem, there is a problem that it is inferior in the essential dust removing property.
Further, in the cleaning sheet used for cleaning and removing these foreign substances, it is desirable to have a cleaning layer composition that does not contaminate the transported portion in the substrate processing apparatus. However, the same consideration is necessary. That is, in order to protect the surface of the cleaning layer and to improve the handleability, the cleaning sheet is usually provided with a separator attached to the surface of the cleaning layer. In many cases, the mold is treated with silicone or wax.
However, in use, when the separator is peeled off, the release agent such as silicone and wax moves and transfers to the cleaning layer, and the cleaning sheet is conveyed into the substrate processing apparatus to remove foreign matters. Then, there exists a problem that said transfer and the transferred mold release processing agent adhere to the conveyance site | part etc. in an apparatus, and contaminate an apparatus.
Therefore, instead of the separator, a cleaning layer surface protective film made of a polyolefin resin has been conventionally used. This type of film exhibits sufficient peelability by itself without being subjected to a mold release treatment with silicone, wax or the like, so that contamination of the apparatus can be avoided. However, when the cleaning sheet is used in an apparatus at about 80 ° C., various additives added at the time of film formation of the polyolefin resin migrate to the cleaning layer, which gasifies or reacts with the residual gas in the apparatus. This is a problem because the inside of the apparatus may still be contaminated.
In light of such circumstances, an object of the present invention is to provide a cleaning sheet that can be reliably transported in a substrate processing apparatus and can easily and reliably remove adhering foreign matter.
[0004]
[Means for Solving the Problems]
As a result of diligent investigations for the above object, the present inventors have carried out a cleaning sheet or a substrate to which the sheet is fixed to remove the adhered foreign matter in the manufacturing apparatus by cleaning. As a protective film, a protective film made of a polyolefin resin and not subjected to release treatment is bonded as a separator, and the total amount of the thermal deterioration inhibitor and the lubricant contained in the protective film is a polyolefin resin. It is found that the contamination of the device due to the separator can be reliably avoided by making it less than 0.01 parts by weight per 100 parts by weight, and the foreign matter can be easily and reliably peeled without causing the above problems, The present invention has been completed.
[0005]
That is, the present invention provides a protective film made of a polyolefin resin and not subjected to a release treatment on at least one surface of a cleaning layer having a 180 ° peel-off adhesive strength to a silicon wafer (mirror surface) of 0.20 N / 10 mm or less. A cleaning sheet characterized in that the total amount of the thermal degradation inhibitor and the lubricant contained in the protective film is less than 0.01 parts by weight per 100 parts by weight of the polyolefin-based resin. 1) A protective film made of polyolefin resin and not subjected to mold release treatment is attached as a separator on one side of the cleaning layer with a 180 ° peel adhesion to the silicon wafer (mirror surface) of 0.20 N / 10 mm or less. Of the heat deterioration inhibitor and lubricant contained in the protective film. The total amount is less than 0.01 parts by weight per 100 parts by weight of the polyolefin-based resin, and a normal pressure-sensitive adhesive layer is provided on the other surface (claim 2), at least one side of the support In addition , a cleaning layer having a 180 ° peel-off adhesive strength with respect to the silicon wafer (mirror surface) of 0.20 N / 10 mm or less is provided, and the surface of the cleaning layer is made of a polyolefin resin and is not subjected to a release treatment. A cleaning sheet wherein the film is bonded as a separator, and the total amount of the thermal degradation inhibitor and the lubricant contained in the protective film is less than 0.01 parts by weight per 100 parts by weight of the polyolefin-based resin ( claim 3), one side of a support, 180-degree peel adhesion to a silicon wafer (mirror surface) .20N / 10 mm or less the cleaning layer is provided, it normal adhesive layer is provided on the other surface, the protective film not subjected to it and releasing treatment of a polyolefin resin at least on the surface of the cleaning layer is a separator And a total amount of the heat deterioration preventing agent and the lubricant contained in the protective film is less than 0.01 part by weight per 100 parts by weight of the polyolefin resin. ) .
Further, the present invention provides the cleaning sheet according to any one of claims 1 to 4, wherein the protective film does not contain a thermal degradation inhibitor and a lubricant (claim 5), or claim 2 or 4. A transport member with a cleaning function, wherein the cleaning sheet is provided on the transport member via a normal adhesive layer (Claim 6) , the cleaning sheet according to Claim 1 or 3, or protection of the transport member according to Claim 6. The present invention relates to a cleaning method for a substrate processing apparatus (Claim 7) , in which the film is peeled off and the cleaning sheet or the transport member is transported into the substrate processing apparatus .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the cleaning sheet of the present invention, a separator made of polyolefin resin and having a thickness of usually 25 to 100 μm is used as a protective film protecting the surface of the cleaning layer. Examples of the polyolefin resin include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer. This type of film exhibits a low critical surface tension and can be set to have a small peeling force with respect to the surface of the cleaning layer without being subjected to a release treatment with silicone or wax as in the case of a polyester film. In addition, in a film made of soft polyvinyl chloride, a large amount of plasticizer contained in the film moves to the surface of the cleaning layer, causing problems of contamination to the substrate processing apparatus, or to an apparatus using hydrogen chloride liberated from polyvinyl chloride. However, there is no such problem with polyolefin resins.
[0007]
Such a cleaning layer surface protective film is produced by adding various additives to the polyolefin resin and processing the film into a film using a film forming apparatus such as an extruder or a calendar. In the present invention, among the above additives, the thermal deterioration inhibitor and the lubricant are not included at all, or even when added, the total amount of both is less than 0.01 parts by weight with respect to 100 parts by weight of the polyolefin resin. It is characterized by being restricted to a slight amount.
[0008]
Examples of the heat deterioration inhibitor include phenolic, aromatic amine, organic sulfur, organic phosphorus, and metal compound types. The lubricant includes higher aliphatic alcohols, fatty acid esters, and fatty acid amides. When the total amount of these thermal deterioration inhibitors and lubricants is 0.01 parts by weight or more with respect to 100 parts by weight of the polyolefin-based resin, transfer of these additives to the surface of the cleaning layer causes them to enter the substrate processing apparatus. It becomes difficult to reliably prevent contamination.
In addition, since the protective film made of the polyolefin resin must be able to withstand a heat drying process at the time of applying an adhesive formed as a cleaning layer, the polyolefin resin as a film forming material has a heat deformation temperature. It is desirable that the load (in accordance with JIS K7207, load 0.45 MPa) is 80 ° C. or higher. Further, such a protective film is not subjected to release treatment.
[0009]
The material of the cleaning layer is not particularly limited. However, the cleaning layer is preferably one that has been cured by an active energy source such as ultraviolet light or heat to have a three-dimensional network structure and a reduced adhesive force, such as a silicon wafer (mirror surface). 180 degree peeling adhesive strength to 0.20 N / 10 mm or less, preferably about 0.010 to 0.10 N / 10 mm. If this adhesive strength exceeds 0.20 N / 10 mm, it may adhere to a non-cleaning part in the apparatus during transportation, resulting in a transportation trouble.
[0010]
As a specific example of such a cleaning layer, for example, a pressure-sensitive adhesive polymer containing a compound having at least one unsaturated double bond in the molecule is preferable.
Such pressure-sensitive adhesive polymers include, for example, acrylic polymers mainly composed of (meth) acrylic acid and / or (meth) acrylic acid ester selected from acrylic acid, acrylic acid ester, methacrylic acid, and methacrylic acid ester. Is mentioned. In synthesizing the acrylic polymer, a compound having two or more unsaturated double bonds in the molecule is used as a copolymerization monomer, or a compound having an unsaturated double bond in the molecule is used in the synthesized acrylic polymer. By introducing an unsaturated double bond into the molecule of the acrylic polymer, such as by a chemical bond between the functional groups, this polymer itself can also participate in the polymerization curing reaction by active energy. it can.
Here, the compound having one or more unsaturated double bonds in the molecule (hereinafter referred to as a polymerizable unsaturated compound) is preferably a non-volatile low molecular weight substance having a weight average molecular weight of 10,000 or less, In particular, it is preferable that the adhesive layer has a molecular weight of 5000 or less so that the three-dimensional network of the adhesive layer can be efficiently formed at the time of curing.
[0011]
The polymerization initiator added to the pressure-sensitive adhesive is not particularly limited and known ones can be used. For example, when heat is used as an active energy source, thermal polymerization initiation of benzoyl peroxide, azobisisobutyronitrile, etc. Benzoyl, benzoin ethyl ether, cibenzyl, isopropyl benzoin ether, benzophenone, Michler's ketone chlorothioxanthone, dodecylthioxanthone, cymethylthioxanthone, acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxycyclohexyl Examples include photopolymerization initiators such as phenyl ketone, 2-hydroxymethylphenylpropane, and 2,2-dimethoxy-2-phenylacetophenone.
The thickness of the cleaning layer is not particularly limited, but is usually about 5 to 100 μm.
[0012]
The present invention also provides a cleaning sheet in which the above-mentioned specific cleaning layer is provided on one side of a support and a normal pressure-sensitive adhesive layer is provided on the other side. In this case, in order to surely avoid the problem of contamination of the substrate processing apparatus, at least the protective film on the cleaning layer side is made of a polyolefin resin and is not subjected to release treatment, and is included in this protective film. It is necessary to use a protective film in which the total amount of the heat degradation inhibitor and the lubricant is less than 0.01 parts by weight per 100 parts by weight of the polyolefin resin.
[0013]
The material of the pressure-sensitive adhesive layer on the other side is not particularly limited as long as it satisfies the pressure-sensitive adhesive function, and a normal pressure-sensitive adhesive (for example, acrylic or rubber) can be used. The thickness is usually about 5 to 100 μm. In the present invention, when the substrate is peeled off from the adhesive after cleaning in order to reuse the conveying member such as the substrate, the adhesive force of the normal adhesive layer is peeled off by 180 ° from the silicon wafer (mirror surface). Is preferably about 0.01 to 10.0 N / 10 mm, particularly about 0.1 to 5.0 N / 10 mm, because it can be easily peeled off after cleaning without peeling during transportation.
[0014]
The protective film used for the pressure-sensitive adhesive layer on the other side is not particularly limited. For example, polyester, polypropylene, and the like that have been subjected to release treatment with a silicone-based, long-chain alkyl-based, fluorine-based, fatty acid amide-based, silica-based release agent, Polyolefins such as polybutene, polybutadiene, and polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene vinyl acetate copolymer, ionomer resin, ethylene (meth) acrylic acid copolymer And a plastic film made of ethylene / (meth) acrylic acid ester copolymer, polystyrene, polycarbonate and the like. The thickness is usually about 10 to 100 μm.
[0015]
The support for the cleaning layer is not particularly limited, and examples thereof include plastic films such as polyethylene, polyethylene terephthalate, acetyl cellulose, polycarbonate, polypropylene, polyimide, polyamide, polycarbodiimide, and nylon film. The thickness of the support film is usually about 10 μm to 100 μm.
[0016]
The transport member to which the cleaning sheet is affixed is not particularly limited, and examples thereof include flat panel display substrates such as semiconductor wafers, LCDs, and PDPs, and other substrates such as compact disks and MR heads.
[0017]
Hereinafter, although the present invention is explained based on an example, the present invention is not limited to this. In the following, “part” means part by weight.
Example 1
To 100 parts of low density polyethylene resin manufactured by Asahi Kasei Co., Ltd., without adding any thermal degradation inhibitor and lubricant, flat film manufacturing equipment (manufactured by Modern Machinery Co., Ltd.) was used. The film was formed at 4 m / min to obtain a cleaning layer surface protective film A having a thickness of 100 μm.
[0018]
Polyethylene glycol 200 dimethacrylate (Shin Nakamura) with respect to 100 parts of an acrylic polymer (weight average molecular weight 700,000) obtained from a monomer mixture composed of 75 parts of 2-ethylhexyl acrylate, 20 parts of methyl acrylate, and 5 parts of acrylic acid Chemical: 50 parts by trade name: Nk ester 4G, 50 parts by urethane acrylate (manufactured by Shin-Nakamura Chemical: trade name: UN-01), 3 parts by polyisocyanate compound (manufactured by Nippon Polyurethane Industry: trade name: Coronate L) , And 3 parts of benzyl dimethyl ketal (manufactured by Ciba Specialty Chemicals: trade name: Irgacure 651) as a photopolymerization initiator were uniformly mixed to prepare an ultraviolet curable adhesive solution. On the other hand, the pressure-sensitive adhesive solution obtained in the same manner as above except that benzyldimethylketanol was removed from the pressure-sensitive adhesive had a thickness of 10 μm after drying on one side of a polyester support film having a width of 250 mm and a thickness of 25 μm. Thus, a normal pressure-sensitive adhesive layer was provided, and a polyester protective film having a thickness of 38 μm was stuck on the surface. Next, the UV curable pressure-sensitive adhesive solution was applied to the other surface so that the thickness after drying was 40 μm to provide a pressure-sensitive adhesive layer as a cleaning layer, and the protective film A prepared above was bonded to the surface. .
The cleaning sheet A of the present invention was obtained by irradiating this sheet with ultraviolet light having a central wavelength of 365 nm and an integrated light quantity of 2000 mJ / cm ² . The tensile modulus after UV curing of the pressure-sensitive adhesive layer of the cleaning layer of this cleaning sheet A was 55 MPa.
Here, the tensile modulus was measured according to the test method JIS K7127.
The pressure-sensitive adhesive layer on the cleaning layer side was affixed to the mirror surface of the silicon wafer with a width of 10 mm, and the 180 ° peel-off adhesive strength to the silicon wafer was measured according to JIS Z0237. As a result, it was 0.029 N / 10 mm.
Moreover, as a result of measuring 180 degree peeling adhesive force with respect to the silicon wafer (mirror surface) of the normal adhesive layer of the other surface side similarly to the above, it was 0.10 N / 10mm.
[0019]
The protective film on the normal adhesive side of the cleaning sheet A was peeled off and attached to the back surface (mirror surface) of an 8 inch silicon wafer with a hand roller to prepare a cleaning wafer A for transport with a cleaning function.
[0020]
Example 2
A cleaning layer protective film B was obtained by adding 0.009 part of a fatty acid ester-based lubricant to 100 parts of a low-density polyethylene resin manufactured by Asahi Kasei Co., Ltd. and forming a film in the same manner as in Example 1. A cleaning sheet B and a transport cleaning wafer B with a cleaning function were produced in the same manner as in Example 1 except that the cleaning layer surface protective film B was used as a separator for the cleaning layer.
[0021]
Comparative Example 1
To 100 parts of a low-density polyethylene resin manufactured by Asahi Kasei Co., Ltd., 0.01 part of a phenol-based thermal deterioration inhibitor and 0.01 part of a fatty acid ester-based lubricant are added, and the film is processed in the same manner as in Example 1 to form a cleaning layer A surface protective film C was obtained. A cleaning sheet C and a transport cleaning wafer C with a cleaning function were produced in the same manner as in Example 1 except that the cleaning layer protective film C was used as a separator for the cleaning layer.
[0022]
Comparative Example 2
To 100 parts of a low density polyethylene resin manufactured by Asahi Kasei Co., Ltd., 0.1 part of a phenol-based thermal degradation inhibitor and 0.1 part of a fatty acid ester lubricant are added, and the film is processed in the same manner as in Example 1 to form a cleaning layer. A surface protective film D was obtained. A cleaning sheet D and a transport cleaning wafer D with a cleaning function were produced in the same manner as in Example 1 except that the cleaning layer protective film D was used as a separator for the cleaning layer.
[0023]
Comparative Example 3
A polyester film having a thickness of 50 μm subjected to silicone treatment was used as the cleaning layer surface protective film E. A cleaning sheet E and a transport cleaning wafer E with a cleaning function were produced in the same manner as in Example 1 except that this cleaning layer protective film E was used as a separator for the cleaning layer.
[0024]
Regarding the cleaning sheets A to E of Examples 1 and 2 and Comparative Examples 1 to 3 described above, the peeling force when the separator (cleaning layer surface protective film) was peeled from the cleaning layer surface was examined. Moreover, the contamination test with respect to the semiconductor wafer of these cleaning sheets A-E and the foreign material removal test in the substrate processing apparatus by the cleaning wafers A-E with a cleaning function were done by the following method. These results were as shown in Table 1.
[0025]
<Wafer contamination assessment>
The cleaning layer of the cleaning sheet was attached to the entire mirror surface of the 8-inch silicon wafer with a hand roller while peeling the separator (protective film). Thereafter, the cleaning sheet was peeled off from the wafer, and foreign matter having a size of 0.2 μm or more adhering to the mirror surface was counted by a laser surface inspection apparatus.
[0026]
<Foreign matter removal test>
Using a laser surface inspection device, foreign matters of 0.2 μm or more on the mirror surface of five new 8-inch silicon wafers were measured and found to be 10, 8, 3, 5, and 11, respectively. After these wafers were transferred to a substrate processing apparatus having separate electrostatic attraction mechanisms with the mirror surface facing downward, the mirror surface was measured with a laser surface inspection apparatus. In the area of 8 inch wafer size, 33156 respectively. , 38945, 32144, 37998, 31327.
[0027]
Next, the protective film on the cleaning layer side of the transport cleaning wafers A to E obtained above was peeled off and transported by a substrate processing apparatus having a wafer stage to which the above foreign matter had adhered, and transported without problems. Thereafter, a new 8-inch silicon wafer was transported with the mirror surface facing downward, and foreign matter of 0.2 μm or more was measured with a laser foreign matter inspection apparatus. This operation was performed 5 times.
[0028]

[0029]
From the above results, as the cleaning layer separator (protective film), an example using a cleaning layer protective film in which the total amount of the thermal degradation inhibitor and the lubricant is less than 0.01 parts with respect to 100 parts of the polyethylene resin. The cleaning sheets 1 and 2 had a peeling force with respect to the cleaning layer surface as small as 0.5 N / 50 mm width or less, and could be easily peeled without causing problems such as partial removal of the cleaning layer composition. In addition, since the number of foreign particles adhering to the silicon wafer is small, it has been found that the use of these cleaning wafers can greatly reduce the contamination of the substrate processing apparatus and has high foreign particle removal properties. On the other hand, in the cleaning sheet of Comparative Examples 1 and 2 where the total amount is outside the scope of the present invention and the cleaning sheet of Comparative Example 3 using a conventional polyester film treated with silicone, the adhesion to the silicon wafer It has been found that there are many foreign substances, and as a result, when these cleaning wafers are used, back-contamination of the apparatus occurs, so that the foreign substance removal property is poor and cannot be used.
[0030]
【The invention's effect】
As described above, in the present invention, the cleaning layer surface protective film (separator) of the cleaning sheet is composed of a polyolefin-based resin that is not subjected to a release treatment, and the amounts of the thermal degradation inhibitor and the lubricant contained therein are determined. By suppressing to a specific value or less, it can be applied to a method for removing adhered foreign matter such as a conveyance part in a substrate processing apparatus, avoiding the problem of contamination of the apparatus caused by a protective film, and obtaining high foreign matter removal properties. it can.

Claims (7)

A protective film made of polyolefin resin and not subjected to a release treatment is bonded as a separator on at least one surface of a cleaning layer having a 180 ° peel-off adhesive strength to a silicon wafer (mirror surface) of 0.20 N / 10 mm or less. And a total amount of the thermal degradation inhibitor and the lubricant contained in the protective film is less than 0.01 parts by weight per 100 parts by weight of the polyolefin resin. A protective film made of polyolefin resin and not subjected to a release treatment is bonded as a separator to one side of a cleaning layer having a 180 degree peeling adhesion to a silicon wafer (mirror surface) of 0.20 N / 10 mm or less. In addition, the total amount of the thermal degradation inhibitor and the lubricant contained in the protective film is less than 0.01 parts by weight per 100 parts by weight of the polyolefin resin, and a normal pressure-sensitive adhesive layer is provided on the other surface. A characteristic cleaning sheet. At least one surface of the support is provided with a cleaning layer having a 180 ° peel-off adhesive strength to the silicon wafer (mirror surface) of 0.20 N / 10 mm or less. The surface of the cleaning layer is made of a polyolefin resin and is released from the mold. A protective film that is not subjected to treatment is bonded as a separator, and the total amount of the thermal degradation inhibitor and the lubricant contained in the protective film is less than 0.01 part by weight per 100 parts by weight of the polyolefin resin. And a cleaning sheet. On one side of the support is provided a cleaning layer having a 180 ° peel adhesion to the silicon wafer (mirror surface) of 0.20 N / 10 mm or less, and a normal adhesive layer is provided on the other side. A protective film made of polyolefin resin and not subjected to release treatment is bonded to the surface of the cleaning layer as a separator, and the total amount of the thermal degradation inhibitor and lubricant contained in this protective film is 100 weight of polyolefin resin. A cleaning sheet characterized by being less than 0.01 parts by weight per part. The cleaning sheet according to claim 1, wherein the protective film does not contain a thermal degradation inhibitor and a lubricant. A conveying member with a cleaning function, wherein the cleaning sheet according to claim 2 or 4 is provided on the conveying member via a normal adhesive layer. A cleaning method for a substrate processing apparatus, wherein the cleaning sheet according to claim 1 or 3 or the protective film of the transport member according to claim 6 is peeled off and the cleaning sheet or the transport member is transported into the substrate processing apparatus.