Apparatus for controlling etch rate when using consumable electrodes during plasma etching

摘要

A method and apparatus to improve process control during plasma etching of semiconductor substrates. Improvements are directed towards controlling the rate of etching when using consumable electrodes. Consumable electrode materials are used to increase selectivity in certain plasma etching processes as in via. contact. or in SOG etch. A consumable electrode material has a significant effect on processing time due to changing gap dimension between electrodes. This invention teaches how to adjust for process variables by using feedback from two strategically placed pressure manometers.