Achieving highly accurate profile control by applying a multi-zone polish head for 200mm thin-film SOI CMP

The specification for the total thickness variation (TTV) of the top Si layer of silicon on insulator (SOI) wafers is getting tightened for the future application [1] [2]. Therefore, the current Chemical Mechanical Polishing (CMP) process cannot meet the flatness requirement, especially at wafer edge, which could cause up to 5% yield loss. This paper describes how an Applied Materials Mirra^® CMP configured with a multi-zone polish head was introduced to develop a new thin film SOI polishing process. The resulting TTV improvements demonstrated by the CMP step generates a competitive and effective method for achieving the best possible profile control.