Natsuyo Morioka

In-situ process monitoring in metal deposition processes

Process monitoring is now receiving more serious attention than ever before in an effort to increase the efficiency of equipment utilization and the stability of process quality in VLSI production lines. The objectives and effects of process monitoring are discussed in this article. The function of various process monitoring tools are also classified and examined in an effort to replace current PQC or inspection procedures. Several of the monitoring technologies developed by our research group are reviewed in detail. Stabilization of the metal deposition processes is thought to be effective in stabilizing the subsequent etching and photo processes. A sputter monitoring system in which essential process parameters are sensed in-situ is shown to be sensitive enough to detect process variations. W-CVD can be monitored by using quadruple mass spectroscopy (QMS) to provide real-time information about the onset of deposition reactions, etc. Simple time control of the deposition is not sufficient to control the process since the metal CVD reaction is susceptible to the surface state. Process tools can still be improved by the development and application of monitoring technology. However, on overall improvement in production efficiency should be attained through a good combination of process monitoring tools and a line control system.