Improvement in throughput of silicon epitaxial process by using in-line moisture monitoring

In epitaxial process, halide and hydrogen halide gases are used as a source gas or chamber cleaning gas. These gases are very corrosive in the presence of moisture. Hence, metal contamination will be very severe problem, if moisture get into epitaxial process. So we investigated the behavior of moisture gotten into the epitaxial process chamber and the relationship between moisture concentration and metal contamination. As a result, they became clear that moisture in the process chamber is promptly adsorbed on the inner surface of the process chamber and it does not leave easily except for HCl gas atmosphere, and that metal contamination level relates to moisture concentration. Therefore, the moisture monitoring and controlling can reduce the frequency of ex-situ metal inspection such as SIMS, SPV and DLTS. The improvement of the throughput is also expected because of inspection time reduction and quick startup after maintenance. The moisture monitoring with spectrometer could be very effective on both cost and quality.