Yield improvement in silicon epitaxy through gas purity analysis and control at the wafer

The characterization of an Applied Materials 7600 silicon epi reactor using a reactor analysis system is described. By analyzing gaseous impurities such as oxygen, moisture (H₂O), and particulates, contaminations introduced by machine design and operation are shown to far outweigh the impurities contained in the inlet materials. The actual testing and analysis involves production epi systems at the materials wafer fab at Harris Semiconductor in Palm Bay, Florida. A case study is presented which shows how, through systematic use of the Linde reactor analysis, contamination levels can be reduced by varying operating parameters such as load time, temperature and housing purge flow rate. Epitaxial film defects and process yield are significantly improved