Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1997-04-23
2001-01-09
Henderson, Christopher (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S200000, C525S326300
Reexamination Certificate
active
06172162
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a sealing composition and a sealant, and more particularly to the sealant which is used preferably for an etching apparatus which is used in the field of semiconductor and liquid crystal display devices.
With the miniaturization and high integration of semiconductor devices and with the increase in the size of liquid crystal display devices and sophistication thereof, dry etching is used as a key technology for miniaturizing the semiconductor devices and sophisticating the liquid crystal display devices. That is, replacing wet etching, dry etching has become increasingly important as a technique of processing fine lines and thin film transistors of the liquid crystal display devices.
Dry etching is classified into reactive plasma etching which is performed, utilizing only chemical reactions of active particles in plasma generated by applying a high-frequency electric field to gas introduced into a chamber; unreactive ion etching which is performed, utilizing only sputtering action caused by ions accelerated by an electric field; reactive sputtering etching which is performed in combination of the reactive plasma etching and the unreactive ion etching. In order to perform the above etching method, the following etching apparatuses have been developed: a plasma etching apparatus, a reactive ion etching apparatus, a reactive ion beam etching apparatus, a sputtering etching apparatus, and an ion beam etching apparatus. Further, a multi-chamber system for successive processing has been developed.
In the etching process which is carried out using the above-described etching apparatuses, there occur V
th
shifts, leaks, increase in the resistance of contacts, corrosion of Al wiring all due to the presence of heavy metals and contamination due to the adherence of polymer to parts of the etching apparatuses, thus causing the deterioration in the quality of semiconductor devices, substrates of liquid crystal display devices, and the deterioration in the yield of product.
Therefore, in order to maintain the quality of the semiconductor devices and that of the substrates of liquid crystal display device, the etching apparatuses are checked and repaired periodically. Normally, the checking and repairing time is determined by the characteristics, strength, and the like of sealants such as a gate valve sealant and a peripheral sealing material. That is, metal ions eluted from sealants affects the yield greatly. This tendency is outstanding in the ion etching apparatus required to be operated in pressure-reduced atmosphere.
The following sealing compositions are known.
A copolymer consisting of tetrafluoroethylene, perfluoromethylperfluorovinyl ether, and monomer having curing portions (disclosed in Examined Japanese Patent Public No. Hei4-81609); and a copolymer containing at least one kind of unsaturated compounds having the property of ethylene and fluorovinyl ether (disclosed in Examined Japanese Patent Publication No. Hei5-63482).
Sealants such as O-rings, peripheral sealants, and the like formed by molding the above-described copolymers containing fluoroalkyl vinyl ether type do not have the high strength requirements of the etching apparatus. It is possible to improve the strength of the above-described copolymers by adding carbon black thereto, but the sealants formed thereof are electrically conductive and thus cracked in the plasma etching apparatus. In order to solve the above-described problems, a sealant containing silica powder used as a filler has been developed. But a lot of a content of metals, especially, a lot of a content of barium is eluted from the sealant, which necessitates checking/repairing of the etching apparatus at short intervals. Thus, the yield of semiconductor devices and substrates of liquid crystal display devices cannot be improved.
Further, the conventional sealant has a problem that it is in capable of maintaining its initial characteristics for a long time when it is used in a high energy-consuming environment, with the recent remarkable progress in the performance of the etching apparatus.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described problems. Accordingly, it is an object of the present invention to provide a sealing composition which is formed into a sealant and maintains its strength and initial characteristic even though the sealant formed thereof is used in a high energy-consuming environment and which can be reduced the elution of metal.
It is another object of the present invention to provide the sealant which is used for an etching apparatus and capable of maintaining its strength and can be reduced the elution of metal.
The sealing composition on the present invention comprises a fluorine-containing elastomer comprising a repeating unit derived from a fluoroolefin and a repeating unit derived from a perfluoroalkyl vinyl ether and 5-50 percent by weight of a fluororesin powder, wherein a content of metal eluted from the sealing composition after curing is not more than 8 ppb.
The fluorine-containing elastomer consists essentially of a repeating unit derived from a tetrafluoroethylene, a perfluoroalkyl vinyl ether, and a fluoroolefin excluding the tetrafluoroethylene or a olefin.
The fluororesin powder is selected from at least one powder of the group consisting of a polytetrafluoroethylene, a tetrafluoroethylene and hexafluoropropylene copolymer, a tetrafluoroethylene and perfluoroalkoxy copolymer, a ethylene and the tetrafluoroethylene copolymer, a ethylene and chlorotrifluoroethylene copolymer, a polychlorotrifluoroethylene, a polyvinylidene fluoride, a polyvinyl fluoride and a vinylidene fluoride type copolymer, and wherein the average diameter of the fluororesin powder have 0.2-50 &mgr;m.
Another sealing composition on the present invention comprises an elastomer and 5-50 percent by weight of the fluororesin powder, wherein the elastomer comprises 100 parts by weight of the fluorine-containing elastomer comprising a repeating unit derived from a fluoroolefin and a perfluoroalkyl vinyl ether and 5-200 parts by weight of a polymer which is selected from at least one of the group consisting of a vinylidene fluoride and hexafluoropropylene copolymer, a vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene copolymer, a propylene and tetrafluoroethylene copolymer, and a fluorosilicone polymer.
The content of metal eluted from the composition is not more than 8 ppb. The fluororesin powder consists of the above-described fluororesin powder.
The sealant for etching apparatus of the present invention is obtained by molding the above-described sealing composition which comprises the fluorine-containing elastomer having a repeating unit derived from a fluoroolefin and a perfluoroalkyl vinyl ether, and 5-50 percent by weight of the fluororesin powder. The content of metal eluted from the sealant after curing is not more than 8 ppb. The hardness is in a range of 50-90°.
Another sealant of the present invention is obtained by molding the above-described another sealing composition. The hardness of the sealant is in a range of 50-90°. The content of metal eluted from the sealant after curing is not more than 8 ppb.
Because the sealing composition of the present invention consists of the above-described substances and does not contain the conventional inorganic filler, it maintains the strength and does not allow the elution of much content of metal after curing. Therefore, the composition can be preferably used as a sealant of semiconductor devices and liquid crystal display devices, thus contributing to the production of quality-improved substrates of ULSI, VLSI, TFTLCD.
The sealant for etching apparatus of the present invention allows the checking/repairing of the etching apparatus to be made at long intervals, thus improving the yield of semiconductor devices and substrates of liquid crystal display device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The fluorine-containing elastomer of the present invention contains
Hedman, Gibson & Costigan, P.C.
Henderson Christopher
Morisei Kako Co., Ltd.
LandOfFree
Fluorine containing elastomeric sealing composition and sealant does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fluorine containing elastomeric sealing composition and sealant, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluorine containing elastomeric sealing composition and sealant will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2445618