| 摘要 |
PURPOSE:To provide an electrode plate for plasma etching use which can perform a stable etching for a long period by forming many small through holes through a highly pure vitreous carbon plate by electric discharge machining. CONSTITUTION:After molding a phenol resin solution into a discoid shape, the molded product is put in an electric furnace maintained in an inert atmosphere and the resin is carbonized by baking the resin at about 800 deg.C. Then the baked body is shifted to a graphitizing furnace and graphitized at about 3,000 deg.C. Thereafter, the vitreous carbon plate is set in an electric discharge machine and a group of small through holes of about 0.8mm in diameter are bored at intervals of about 2mm by using copper electrodes under such a condition that the number of electric discharge repeating times is controlled to about 15,000 times/sec. After boring, the vitreous carbon plate is shifted to an ashing furnace which subjects the carbon plate to high-purity ashing by heating the carbon plate while a chlorine gas is made to flow in the furnace. Therefore, an electrode plate for plasma etching which can perform a highly accurate stable etching for a long time without causing any trouble through the etching process can be obtained. |
