Semi-empirical Material Removal Model with Modified Real Contact Area for CMP

Abstract

Chemical mechanical polishing (CMP) is essential in semiconductor processing and has recently widened its scope of application. However, the study on its mechanisms is still in progress. Understanding the CMP process requires an understanding of the various physical and chemical reactions that occur at the pad-wafer interface. Moreover, understanding the real contact area (RCA) between the polishing pad and the wafer in the CMP process is essential for predicting the material removal rate (MRR) and understanding the overall process. In this study, a modified mathematical model for the RCA was developed and validated experimentally. The model of the RCA proposed in this study was used to establish the MRR model and predict the MRR under various pressure values and the effect of abrasive particle size and its distribution. Specifically, the experimentally obtained values were compared with the values obtained by the model and the comparison results were analyzed. Thereby, it was found that the RCA model and the MRR model proposed in this study were in good agreement with the experimental results, which shows that the MRR can be predicted by a mathematical model using the measurement of the RCA.