STATISTIC CORRELATION ANALYSIS OF POST CMP PLANARITY WITH POLISHING PAD PROPERTIES

摘要

With the aid of Statistic Correlation and Grey Correlation analysis, a post CMP step height regression model which precisely fitted the experiment results was developed successfully in our study. Key polishing pad properties, which were highly corresponding to the post CMP planarity, were first identified by the Statistic Correlation and Grey Correlation Analysis methods. Once these key factors were decided, the Multiple Regression Analysis method was applied to build up a model correlating post CMP step height with pad properties. According to this regression model, we can get a clear picture about the influence of pad properties on post CMP step height. We find that stacked pad deflection and hardness are two major pad properties governing the post CMP planarity according to the analysis results. By checking the correlation of stacked hardness and deflection, these two properties are not independent to each other and the correlation is not low. This explains the model built with deflection and stacked thickness yield better fitness than the model built with stacked hardness and deflection on both Mirra and STRASBAUGH 6DS polishers.