ELECTRODE PLATE FOR PLASMA ETCHING DEVICE

PURPOSE:To get a plasma etching device which withstands long-term use and besides has wide use property without polluting a silicon wafer by using silicon carbide silicified of vitreous carbon as an electrode plate. CONSTITUTION:Many holes 0.8mm in diameter are opened at intervals of 3mm in a carbon plate 1.5g/cm in density, 200mm in diameter, and 3mm in length, and then it is put in a silicifying furnace, and is heated to 1700 deg.C, thus it is silicified while passing SiO gas for three hours. The thickness of the silicified electrode plate obtained is 1.5mm, and it silicifies most of vitreous carbon, and the shrinkage area in diametrical direction is 0.09mm, and the density is 2.5g/cm , and the flexural strength is 2k/mm . When this electrode plate is installed in a plasma etching device, and the plasma etching of a silicon wafer is executed while passing CF4 gas, the silicon wafer is not polluted, and extremely equal etching can be performed. What is more, corrosion is hardly found in the electrode plate.