JPS6421927A - Method and apparatus for judging end point of etching and usage thereof - Google Patents

Abstract

PURPOSE:To improve the reproducibility of plasma etching of a sample and to expand the freedom in juding the end point of the plasma etching of the sample, by detecting the intermediate change in amount of light after the decrease or increase in amount of the light against a light emitting time when the plasma etching is yielded. CONSTITUTION:After the decrease or increase in amount of light against the plasma etching time (b) with light, which is emitted during the plasma etching of a sample, the intermediate change in amount of the light is detected. Thereafter, the change after the intermediate change in amount of the light is detected. Thus the end point of the etching of the sample is judged. For example, when a pattern density is coarse and dense, light emitting intensity (a) starts to decrease gradually at a time point, when a time t0 has elapsed from the start of the etching. Thereafter, at a time point when a time t1 is reached, the light emitting intensity becomes a constant intensity once. Thereafter, the light emitting intensity starts to decrease again at time point when a time t2 is reached. At a time t3 in the decreasing step, the etching is finished. In this way, the etching at a part, where the pattern density is coarse, is almost finished at the time t1 when the step phenomenon in light emission starts to appears. The etching remains at a part, where the pattern dinsity is dense.