Insights into HF-Last Processes and Particle Performance in a Single Wafer Spin Cleaning Tool

摘要

Single wafer cleaning technology has gained increasing attention in semiconductor manufacturing for the requirements of cycle time, flexibility, and cost-of-ownership in fab operations. Although many of the theories and fundamental concepts of wet wafer surface preparation may remain similar, the change from a batch immersion platform to single wafer spin processing tool has led to challenges in some applications such as HF-last processes. Unlike fully surrounded with HF and DI water in an immersion wet bench, sensitive silicon substrate can be exposed to the atmospheric environment in a single wafer spin tool once the Si wafer turns to hydrophobic surface through HF etching. High counts of particles and watermarks are typically seen in this circumstance. It has been addressed [3-5] that the environment (rinse water and airflow field) in which the wafers are processed is critical in preventing watermarks. However, very little data of particle performance on HF-last by single wafer spin tools were reported.