Cleaning sheet and method of cleaning substrate treatment apparatus using the same

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a sheet for cleaning various substrate processing devices and a method for cleaning the substrate processing device using the same, for example, a substrate that dislikes foreign substances such as a manufacturing device such as a semiconductor, a flat panel display, and a printed circuit board, and an inspection device. Regarding the cleaning sheet and cleaning method of the processing device.

【0002】

[Conventional technology]

Various substrate processing devices convey each transfer system while physically contacting the substrate. At that time, if foreign matter adheres to the substrate or the transport system, the subsequent substrates will be contaminated one after another, and it is necessary to periodically stop the apparatus and perform the cleaning process. For this reason, there are problems that the operating rate is lowered and a large amount of labor is required. In order to solve these problems, a method of cleaning and removing foreign substances adhering to the substrate processing apparatus by transporting a substrate to which an adhesive substance is fixed (Japanese Patent Laid-Open No. 10-154686), transporting a plate-shaped member. A method of removing foreign matter adhering to the back surface of the substrate (Japanese Patent Laid-Open No. 11-87458), a method of using a dummy wafer charged by corona charge (Japanese Patent Laid-Open No. 2000-260671), and the like have been proposed.

【0003】

[Problems to be Solved by the Invention]

A method of cleaning and removing the adhered foreign matter in the substrate processing apparatus by transporting a substrate on which an adhesive substance is adhered is an effective method for overcoming the above-mentioned problems. However, in this method, the adhesive substance and the contact portion of the device may be strongly adsorbed and may not be peeled off, and the substrate may not be reliably conveyed. In particular, when a vacuum suction mechanism is used for the chuck table of the substrate, the risk is great. Further, the method of removing the foreign matter by transporting the plate-shaped member can be carried out without any trouble, but there is a problem that the essential dust removing property is inferior. Further, the method of using a dummy wafer charged by corona charge is an effective method of removing foreign matter in the vicinity of the wafer, but if the surface potential thereof is to be increased, the corona generation potential must be increased, and the present invention has no choice but to increase the corona generation potential. When such a cleaning sheet is used, depending on the constituent material, the corona treatment conditions cannot be strengthened due to holes, etc., and the surface potential cannot be obtained. Therefore, the corona method can only charge several tens of V, and foreign matter. Suction was still inadequate. In light of these circumstances, an object of the present invention is to provide a cleaning sheet capable of reliably transporting a substrate into a substrate processing apparatus and easily and reliably removing foreign substances adhering to or floating in the apparatus. There is.

【0004】

[Means for solving problems]

As a result of diligent studies in order to achieve the above object, the present inventors clean the adhering or floating foreign matter in the substrate processing apparatus by cleaning or transporting a transport member such as a substrate to which this sheet is fixed. We have found that by using a cleaning sheet having a surface potential of a sheet having a cleaning layer exceeding 10 KV, foreign matter can be easily and surely peeled off and removed without causing the above-mentioned problems, and the present invention has been completed. Tsuta.

【0005】

That is, the present invention is characterized in that the surface potential of the sheet having the cleaning layer exceeds 10 KV (claim 1), and the cleaning layer is converted into an electric stone (electlet) by the thermal electlet method. The cleaning sheet according to claim 1 (claim 2), the cleaning sheet according to claim 1 or 2, wherein the cleaning layer does not have substantially adhesiveness, and the tensile strength of the cleaning layer. The cleaning sheet (claim 4) according to any one of claims 1 to 3, wherein an adhesive layer is provided on one side of the cleaning layer. The cleaning sheet (claim 5), the cleaning sheet according to any one of claims 1 to 4, wherein a cleaning layer is provided on at least one side of the support (claim 6), and a cleaning layer is provided on one side of the support. The present invention relates to the cleaning sheet (claim 7) according to any one of claims 1 to 4, wherein an adhesive layer is provided on the other surface.

【0006】

BEST MODE FOR CARRYING OUT THE INVENTION

In the cleaning sheet of the present invention, the surface potential of the cleaning layer (hereinafter, including the cleaning sheet alone, the laminated sheet, or the laminated sheet with the support) may be in the range of more than 10 KV, and is usually 10 About 50 KV is preferable, and in the present invention, since the cleaning layer has a surface potential in such a specific range, an electric field is formed around the cleaning layer even when the cleaning layer has substantially no adhesiveness as described later. Therefore, it has a strong adsorption force, and it is considered that the dust removal effect can be obtained due to the adsorption force. The method for maintaining such a surface potential is not particularly limited, but for example, various polymers are electretized (hereinafter referred to as electretization) by a thermal electret method or the like, a material having a high volume resistivity is selected, and a current flowing through the substance is selected. There are methods such as making it smaller and making it difficult to discharge.

【0007】

The material of such a polymer is not limited as long as it can be made into an electlet, and for example, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyvinylidene chloride, vinylidene chloride, vinylidene trifluoride, polytetrafluoroethylene and the like can be used. Examples thereof include polymers and curable pressure-sensitive adhesive compositions in which the cross-linking reaction and curing are promoted by an active energy source such as ultraviolet rays or heat, which will be described later.

【0008】

It is preferable that the cleaning layer of the present invention does not have substantially adhesiveness. Here, the fact that there is substantially no adhesiveness means that there is no pressure-sensitive tack that represents the function of adhesiveness when the essence of adhesiveness is friction, which is resistance to slippage. This pressure-sensitive tack develops in the elastic modulus of the sticky substance up to 1 MPa according to, for example, Dahlquist's standard. Therefore, in the present invention, transport troubles occur by designing the tensile strength of the cleaning layer within a specific range, that is, within a range of 1 to 3000 MPa, preferably 100 to 2000 MPa so that the elastic modulus of the cleaning layer becomes larger than 1 MPa. Foreign matter can be removed without doing so. Here, the tensile strength is measured according to the test method JIS K7127.

【0009】

The cleaning layer is preferably one in which the cross-linking reaction and curing are promoted by an active energy source such as ultraviolet rays or heat, and the tensile strength thereof can be increased. Further, it is preferable that it does not easily get wet with the part to be cleaned in the device. If it gets wet easily, the cleaning sheet may come into close contact with the part to be cleaned during transportation, which may cause transportation trouble. The thickness of the cleaning layer is not particularly limited, but is usually about 5 to 100 μm.

【0010】

As a specific example of such a cleaning layer, for example, a pressure-sensitive adhesive polymer containing at least a compound having one or more unsaturated double bonds in the molecule and a polymerization initiator is subjected to a polymerization curing reaction by active energy. Examples thereof include those in which the adhesiveness is substantially eliminated. Examples of such pressure-sensitive adhesive polymers include acrylic polymers containing (meth) acrylic acid and / or (meth) acrylic acid ester selected from acrylic acid, acrylic acid ester, methacrylic acid, and methacrylic acid ester as main monomers. Be done. In synthesizing this acrylic polymer, a compound having two or more unsaturated double bonds in the molecule is used as the 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 by chemically bonding it in a reaction between functional groups, the polymer itself can be involved in the polymerization curing reaction by active energy. You can also.

【0011】

Here, the compound having one or more unsaturated double bonds in the molecule (hereinafter referred to as a polymerizable unsaturated compound) is preferably a low molecular weight compound that is non-volatile and has a weight average molecular weight of 10,000 or less. In particular, it preferably has a molecular weight of 5000 or less so that the cleaning layer can be efficiently reticulated during curing.

【0012】

The polymerization initiator added to the cleaning layer is not particularly limited, and known ones can be used. For example, when heat is used as the active energy source, thermal polymerization initiation of benzoyl peroxide, azobisisobutyronitrile, or the like can be used. When using an agent or light, benzoyl, benzoin ethyl ether, cibenzyl, isopropylbenzoin ether, benzophenone, Michler's ketone chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxycyclohiki Photopolymerization initiators such as sylphenyl ketone, 2-hydroxydimethylphenyl propane, and 2,2-dimethoxy-2-phenylacetophenone can be mentioned.

【0013】

The present invention provides a cleaning sheet (claim 5) in which an adhesive layer is provided on one side of the specific cleaning layer, and the specific cleaning layer is provided on one side of the support and adheres to the other surface. A cleaning sheet provided with a sex layer (claim 7) is also provided. The material of this adhesive layer is not particularly limited as long as it satisfies the adhesive function, and an ordinary adhesive (for example, acrylic type, rubber type, etc.) can be used. With such a configuration, the cleaning sheet is attached to various substrates and other transport members such as tape sheets by this adhesive layer, and is transported into the apparatus as a transport member with a cleaning function (claim 8). It can be cleaned by contacting it with the part to be cleaned (claim 9).

【0014】

In the present invention, when the substrate is peeled from the adhesive layer after cleaning in order to reuse the transport member such as the substrate, the adhesive strength of the adhesive layer is 180 ° peeling with respect to the silicon wafer (mirror surface). When the adhesive strength is 0.20 to 0.98N / 10mm, particularly about 0.40 to 0.98N / 10mm, it is preferable because it does not peel off during transportation and can be easily peeled off after cleaning.

【0015】

The support of the cleaning sheet (claims 6 and 7) in which the cleaning layer is provided on at least one surface of the support is not particularly limited, but for example, polyethylene, polyethylene terephthalate, acetyl cellulose, polycarbonate, polypropylene, polyamide, polyimide, etc. Examples thereof include plastic films such as polycarbodiimide. Its thickness is usually about 10 to 100 μm.

【0016】

The transport member to which the cleaning sheet is attached is not particularly limited, and examples thereof include semiconductor wafers, substrates for flat panel displays such as LCDs and PDPs, and substrates such as compact discs and MR heads.

【0017】

[Example]

Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto. In the following, the term "part" means a part by weight. Example Dipentaerythrolhexa with respect to 100 parts of an acrylic polymer (weight average molecular weight 700,000) obtained from a monomer mixture consisting of 75 parts of -2-ethylhexyl acrylate, 20 parts of methyl acrylate, and 5 parts of acrylic acid. 150 parts of acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd .: trade name UV1700B), 5 parts of benzyl dimethyl ketal, and 3 parts of diphenylmethane diisosianate were uniformly mixed to prepare an ultraviolet curable adhesive solution.

【0018】

On the other hand, a polyethylene terephthalate having a width of 250 mm, a thickness of 70 μm, and a tensile strength of 250 MPa was dried on one side of the support film by applying a pressure-sensitive adhesive solution obtained in the same manner as above except that benzyl dimethyl ketal was removed from the above-mentioned pressure-sensitive adhesive. After that, it was applied so as to have a thickness of 10 μm to provide a normal adhesive layer, and a polyester-based release film having a thickness of 38 μm was attached to the surface thereof. The above-mentioned ultraviolet curable pressure-sensitive adhesive solution was applied to the other surface side of the support film so that the thickness after drying was 40 μm to provide a cleaning layer, and a similar release film was attached to the surface thereof. Ultraviolet rays with a central wavelength of 365 nm are applied to this sheet from the cleaning layer side.²After irradiation, the release film on the cleaning layer side is peeled off, inserted between the electrodes in the atmosphere using the thermal electret method, a voltage of 20 KV is applied at 100 ° C, and then cooled to 40 ° C with the voltage applied. After that, the voltage application was finished and the electret was formed. The surface potential was measured at an electrode-sample distance of 20 mm with an electrostatic measuring instrument (Model FMX002 manufactured by Simco Japan) under the conditions of 25 ° C and 55% RH, and it was 15 KV. Further, the surface of the cleaning layer had substantially no adhesiveness, and the tensile strength of the cleaning layer after UV curing was 1980 MPa. In addition, the normal adhesive layer on the other side was attached to the mirror surface of the silicon wafer with a width of 10 mm, and the 180 ° peeling adhesive strength to the silicon wafer was measured according to JIS Z 0237. As a result, it was 0.25 N / 10 mm. ..

【0019】

The release film on the normal adhesive layer side of the obtained cleaning sheet was peeled off and attached to the back surface (mirror surface) of an 8-inch silicon wafer with a hand roller to prepare a transport cleaning wafer with a cleaning function.

【0020】

On the other hand, when the foreign matter of 0.2 μm or more on the mirror surface of two new 8 inch silicon wafers was measured with a laser type foreign matter measuring device, the first one was 11 and the second was 10. After transporting these wafers to a substrate processing device having separate electrostatic adsorption mechanisms with the mirror surface facing downward, the mirror surface was measured with a laser-type foreign matter measuring device. There were 32004 and 25632.

【0021】

Next, the release film on the cleaning layer side of the transport cleaning wafer obtained above was peeled off, and the film was transported into a substrate processing apparatus having a wafer stage to which the above 32004 foreign substances had adhered, and the transfer was successful. After that, a new 8 inch silicon wafer containing 10 foreign substances of 0.2 μm or more was conveyed with the mirror surface facing downward, and the foreign substances of 0.2 μm or more were measured with a laser type foreign matter measuring device. This process was performed 5 times and the results are shown in Table 1.

【0022】

Comparative example In the cleaning sheet of the example, the same as in the example except that 20 parts of an additive (manufactured by Mitsubishi Chemical Corporation, product name V-SQ-S6) having a quaternary ammonium salt having a conductive function in the side chain was added to the cleaning layer. I got a cleaning sheet. The surface potential of the cleaning layer measured after irradiation with ultraviolet rays was 0.04 KV and the tensile strength was 1720 MPa as in the examples.

【0023】

The cleaning wafer for transfer prepared from this cleaning sheet by the same method as in the example was transferred into a substrate processing apparatus having a wafer stage to which 25632 foreign substances were attached 5 times in the same manner as in the example, and the result was obtained. It is shown in Table 1.

【0024】

[table 1]

<img file="JP2002192084A_D0001.tif" />【0025】

[Effect of the invention]

As described above, according to the cleaning sheet of the present invention, it is possible to reliably convey the inside of the substrate processing apparatus and to easily and surely remove the foreign matter adhering to or floating in the apparatus.