Process for manufacturing a product of glassy carbon

Details Process for manufacturing a product of glassy carbon Process for manufacturing a product of glassy carbon

1999-05-17

2001-06-12

Hendrickson, Stuart L. (Department: 1754)

Chemistry of inorganic compounds

Carbon or compound thereof

Elemental carbon

C423S460000

Reexamination Certificate

active

06245313

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a process for manufacturing a product of glassy carbon, and more specifically to a method of manufacturing a structural member of glassy carbon used in a semiconductor manufacturing apparatus under elevated temperature of 500° C. or higher.
Structural members made of glassy carbon are excellent in chemical stability and mechanical strength, and therefore they are used in portions of, for example, a semiconductor manufacturing apparatus, which are exposed to high temperature and require high mechanical strength.
The conventional process for manufacturing a structural member of glassy carbon will now be briefly described. First, a raw material resin is polymerized in a mold, and cured, thus obtaining a semi-processed piece having a predetermined shape. Then, the piece is baked. The baked piece is subjected to machining and grinding, and thus a product of a final shape is obtained. The obtained product is subjected to ultrasonic cleaning in pure water, and lastly, it is inspected of dimensions, shape and surface defection.
In the conventional manufacturing process, as described above, after baking of the molded piece, machining process is carried out to obtain a product to have a final shape. However, during the machining process, fine cracks or scratches (to be called as micro-cracks hereinafter) may be created.
When cyclic stress is applied at elevated temperature onto to such a glassy carbon material, or when thermal stress by exposure to temperature changes is applied thereto, micro cracks grow to become fatigue cracks. As a result, the glassy carbon product is broken after relatively short time.
BRIEF SUMMARY OF THE INVENTION
The present invention has been proposed in consideration of the drawbacks of the glassy carbon product manufactured by the conventional manufacturing process, and the object thereof is to provide a process for manufacturing a product of glassy carbon having an endurance strength to fatigue at elevated temperature, and to thermal fatigue.
Therefore, according to the present invention, there is provided a process for manufacturing a product of glassy carbon, which includes the steps of:
preparing a piece made of glassy carbon by curing a raw material resin in a mold and baking the cured resin;
machining the piece into a predetermined shape;
impregnating the raw material resin into a surface of the piece machined; and
transforming the resin into glassy carbon by baking the piece to which the resin has been impregnated.
According to the present invention, the resin is impregnated to the surface of the piece which has been machined, and then the resultant piece is baked. Thus, micro-cracks created on the surface of the piece are filled with the resin, and therefore it becomes possible to obtain a glassy carbon product having less surface defects. Consequently, the fatigue strength at elevated temperature and thermal fatigue strength of the glassy carbon product can be improved.
It should be noted that as the resin, a material prepared by polymerizing furan-based material such as furfural or imide-based material can be used.
The impregnation of the resin into the surface of the piece after the machining process can be carried out by coating, or dip coating carried out under a reduced pressure atmosphere or high pressure atmosphere.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.


REFERENCES:
patent: 3632385 (1972-01-01), Schmitt et al.
patent: 3927186 (1975-12-01), Vinton et al.
patent: 45-11004 (1970-04-01), None
patent: 2-173269 (1990-07-01), None
patent: 7-22385 (1995-01-01), None

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