| Summary: | 碩士 === 長庚大學 === 化工與材料工程研究所 === 93 === In semiconductor manufacturing, chemical mechanical polishing (CMP) is the key technology to carry out global planarization at integrated circuit. In CMP, lots of factors result in process variations. Therefore, how to effectively decrease or eliminate the variation sources is an important issue. This study uses the popular Preston equation to modify process models. The empirical parameters of the mechanical mechanism are considered in the modified model. Due to the uncertain effects of the chemical mechanism, parameters for these chemical effects are combined with the Preston’s constants. The obtained analytical model can provide more effective description between removal thickness and over polish time than empirical model.
In this work, we collect lots of on-line CMP data from fab and adopt practical operation, then introduce run-to-run (R2R) control scheme to handle CMP process. The results show that the suitable recipe input is provided to overcome the unknown disturbances. One can use the modified double EWMA control to adjust over polish time, and to make the nitride thickness achieve the process target.
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