Comparing rapid thermal process and low-temperature furnace annealed poly test wafers by SIMS and FTIR

Abstract

As the poly deposition process monitor, poly test wafers (TWS) run with production wafers are generally annealed using the rapid thermal process (RTP) to achieve fast, stable results. But real production wafers often receive an extended, low-temperature furnace thermal process after poly deposition. For this reason, there is always a question about whether or not RTP effectively simulates the thermal budget the device wafers receive during the whole process. During this study, the same processed poly films, both n-type and p-type, go through the RTP furnace for 8 hours at 600/spl deg/C. Comparing the secondary ion mass spectrometry (SIMS) profile and Fourier transform infrared spectroscopy (FTIR) of the Si-H bond led us to question whether the RTP process is reliable enough to be used as the poly deposition process monitor.