METHOD AND APPARATUS FOR JUDGING ETCHING TERMINAL POINT AND METHOD FOR ETCHING INSULATION FILM USING THEREOF

摘要

PURPOSE: A method and apparatus for judging an etching terminal point are provided which can detect the etching terminal point of a semiconductor wafer stably, only with a semiconductor wafer with a low aspect ratio. CONSTITUTION: A method for judging an etching terminal point in a dry etching includes the steps of: reducing noise of an input signal waveform by a first digital filter(18); calculating differential coefficients(first or second order) of the signal waveform by differential calculus by an operational circuit(19); calculating a smoothing differential coefficient value by reducing the noise component of the time-series differential coefficient waveform by a second digital filter(20); and judging the etching terminal point by comparing the smoothing differential coefficient with the established value by a discrimination part(22).