Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
2002-12-13
2004-11-23
Buttner, David J. (Department: 1712)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S041500, C428S041800, C428S041900, C428S343000, C428S352000
Reexamination Certificate
active
06821620
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a sheet for cleaning various devices, a cleaning sheet for a substrate processing equipment that is very susceptive to influences from the foreign matter, for example, a manufacturing system, a test system, etc. for a semiconductor device, a flat panel display, a printed substrate, etc., and a conveying member using the same, and a substrate processing equipment cleaning method using them.
BACKGROUND ART
Various substrate processing equipments convey the substrate while physically contacting the substrate to respective conveying systems. At that time, if the foreign matter is stuck to the substrate and the conveying system, subsequent substrates are contaminated sequentially, and thus the equipment must be stopped periodically and subjected to the cleaning process. For this reason, there is the problem such that the reduction in the rate of operation is caused and the great labor is needed. In order to overcome these problems, the method of cleaning/removing the foreign matter adhered to the inside of the substrate processing equipment by conveying the substrate to which the adhesive substance is adhered (For example, Unexamined Japanese Patent Publication 10-154686), the method of removing the foreign matter adhered to the back surface of the substrate by conveying the plate-like member (Unexamined Japanese Patent Publication 11-87458), the method of employing the dummy wafer charged by the corona charge (Unexamined Japanese Patent Publication 2000-260671), etc. were proposed.
The method of cleaning/removing the foreign matter adhered to the inside of the substrate processing equipment by conveying the substrate to which the adhesive substance is adhered is the effective method to overcome the above subjects. However, there is such a possibility that the adhesive substance is not released because the adhesive substance and the equipment contact portion are too strongly adhered not to release, so that there is such a possibility that the substrate cannot be surely conveyed. Particularly, if the low pressure sucking mechanism is employed in the chuck table of the table, such possibility is great. Also, the method of removing the foreign matter by conveying the plate-like member can execute the conveyance without hindrance, but there is the problem that the vital dust removing characteristic is inferior. Also, the method of employing the dummy wafer charged by the corona charge is the effective method that can also remove the foreign matter in the neighborhood of the wafer, but the corona generation potential must be set higher if the surface potential is tried to increase. Thus, if the cleaning sheet is employed as in the present invention, the corona processing conditions are not strongly set because the holes are opened depending on the constituent material, and also the surface potential cannot be increased. Therefore, the surface potential can be charged up to only several tens V by the corona method and thus the suction of the foreign matter is not sufficient yet.
DISCLOSURE OF INVENTION
The present invention has been made in light of such circumstances, and it is an object of the present invention to provide a cleaning sheet that makes it possible to convey the substrate in the substrate processing equipment without fail and also to simply reduce the foreign matters adhered to the equipment.
In order to achieve the above object, as the result of the earnest study, it was found that a cleaning sheet or a conveying member can be conveyed in the substrate processing equipment without fail and foreign matters can be simply and certainly removed by conveying the cleaning sheet or the conveying member having the cleaning sheet such as a substrate to remove foreign matters away from the interior of a substrate processing equipment, wherein an adhesive layer as a cleaning layer has a surface resistivity not less than a specific value, or has a relative dielectric constant or a surface potential not less than a specific value, or has a surface free energy not less than a specific value, to thereby achieve the present invention.
That is, the present invention relates to a cleaning sheet having a cleaning layer whose surface resistivity is not less than 1×10
13
&OHgr;/□. The cleaning sheet may be provided with a base material. The cleaning layer set forth may be provided on one surface of a base material and an ordinary adhesive layer may be provided on another surface thereof. A relative dielectric constant of the cleaning layer is preferably larger than 2.0. A surface free energy of the cleaning layer is preferably not less than 30 mJ/m2. A surface potential of the cleaning layer preferably exceeds 10 kV. The cleaning layer may be formed as an electret by a thermal electret method. The above cleaning sheets may be further modified from other aspects.
Features and advantages of the invention will be evident from the following detailed description of the exemplary embodiments.
Exemplary Embodiments for Carrying Out the Invention
The cleaning sheet of the present invention has a cleaning layer (including the cleaning layers as modes such as a cleaning sheet single body, a laminated sheet, a laminated sheet of the cleaning sheet and a base material, or the like hereinafter) whose surface resistivity is not less than 1×10
13
&OHgr;/□, preferably not less than 1×10
14
&OHgr;/□. In the present invention, since the cleaning layer is formed as close to the insulator as possible by designing the surface resistivity of the cleaning layer to exceed a specific value, there can be achieved such an advantage that the foreign matters caused by not only the adhesion but also the static electricity can be caught and adsorbed. Accordingly, in case the surface resistivity is set below 1×10
13
&OHgr;/□, the capture/adsorption effect of the foreign matters caused by such static is remarkably lowered.
Further, it is desirable that the above cleaning layer should be formed of material whose relative dielectric constant measured under following conditions is larger than 2.0, preferably not less than 2.1 and more preferably from 2.1 to 10. In the present invention, since the cleaning layer is formed close to the high-dielectric material as much as possible by designing the relative dielectric constant of the cleaning layer to exceed such specific value, there can be achieved such an advantage that the foreign matters caused by the static electricity can be caught and adsorbed.
The relative dielectric constant signifies the magnitude of the electrical energy stored when the electric field is applied to the material by using a ratio to the dielectric constant in a vacuum, and measured based on JIS K6911.
The material, the design method, etc. of such cleaning layer is not particularly limited inasmuch as the relative dielectric constant is set within the above range. In the present invention, it is preferable that the organic material that does not contain conductive material such as the additive having the electrically conducting function should be employed. As particular examples, for example, in addition to the material obtained by causing the compound, that has one unsaturated double bond or more in the molecule, to contain into the pressure-sensitive adhesive polymer, there may be employed preferably rubbers, natural resins, synthetic resins such as polyethylene terephthalate, phenol resin, polyester resin, alkyd resin, epoxy resin, polycarbonate, cellulose nitrate, poly(vinylidene fluoride), polypropylene, polyimide, nylon 6, nylon 66, poly(methyl methacrylate), methyl methacrylate/styrene copolymer, ethylene fluoride/propylene copolymer, etc.
Also, it is desired that the surface free energy of the cleaning layer should be not less than 30 mJ/m
2
, preferably from 40 to 60 mJ/m
2
. In the present invention, the surface free energy of the cleaning layer (solid state) signifies the surface free energy value of the solid state that is obtained by measuring contact angles of the water and the methylene
Namikawa Makoto
Terada Yoshio
Toyoda Eiji
Buttner David J.
Keehan Christopher
Nitto Denko Corporation
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