Etching end point judging method, etching end point judging device, and insulating film etching method using these methods

摘要

Etching end point judging method that includes the following steps in a dry etching end point judging method having a step of reducing noise of input signal waveforms using first digital filter, a step of obtaining a differential coefficient (primary or secondary) of a signal waveform from differential processing by operation circuit, a step of obtaining a smoothed differential coefficient value by reducing the noise components of the time series differential coefficient waveform that was obtained in the previous step, using the second digital filter, and a step of judging an etching end point by comparing the smoothed differential coefficient value and a preset value using discrimination method.