METHOD FOR PLASMA ETCH CHEMISTRY OF SEMICONDUCTOR WAFERS

摘要

A method for plasma etch chemistry of semiconductor wafers consists in realization of etching in plasma formed by electric discharge in a vacuum chamber with puffing and degassing actuation gas. Control of plasma etch chemistry process end is fulfilled with two electrical probes, which are brought in charging zone, a first one is located near semiconductor wafer from degassing side, a second one from side of actuation gas puffing at the same distance from wafers. Values of floating voltage, which are registered by the first and second electrical probes, are transformed into electrical frequency signals, frequency of which is dependent from value of plasma floating voltage. Frequency signals are compared one with another, by difference value, a moment of plasma etch chemistry process end is determined.