POLYSILICON RTCVD PROCESS OPTIMIZATION FOR ENVIRONMENTALLY-CONSCIOUS MANUFACTURING

In the semiconductor manufacturing industry, optimization of advanced equipment and process designs must include both manufacturing metrics (such as cycle time, consumables cost, and product quality) and enviro nmental consequences (such as reactant utilization and by-product emis sion), We have investigated the optimization of rapid thermal chemical vapor deposition (RTCVD) of polysilicon from SiH(4)as a function of p rocess parameters using a physically-based dynamic simulation approach , The simulator captures essential time-dependent behaviors of gas flo w, heat transfer, reaction chemistry, and sensor and control systems, and is validated by our experimental data, Significant improvements in SiH4 utilization (up to 7x) and process cycle time (up to 3x can be a chieved by changes in 1) timing for initiating wafer heating relative to starting process gas dow; 2) process temperature (650-750 degrees C ); and 3) gas flow rate (100-1000 seem). Enhanced gas utilization effi ciency and reduced process cycle time provide benefits for both enviro nmental considerations and manufacturing productivity (throughput), Dy namic simulation proves to be a versatile and powerful technique for i dentifying optimal process parameters and for assessing tradeoffs betw een various manufacturing and environmental metrics.