IDENTIFICATION FOR COMPLICATED SHAPE OBJECTS BY USING STOCHASTIC FRACTAL VARIABLES - CATEGORIZING DUST PARTICLES ON LSI WAFER SURFACE

Improving the yield and stability of LSI wafer production requires tha t the number of dust particles during every process of the production be decreased. To do this, we must develop a method of identifying dust particles. However, the current method of inspecting LSI wafers depen ds on human judgment; this makes it difficult to develop an algorithm to identify dust particles with complex shapes because mathematical mo dels of dust particles have not been created. With this study, we prop ose the so-called ''stochastic fractal variable'' to make the mathemat ical model and identify the dust particles by using the maximum-likeli hood method. Furthermore, we confirm the effectiveness of the identifi cation method we propose by categorizing actual data.