Two sensor techniques and a data analysis algorithm have been investigated, to assess their suitability for in-situ process monitoring and integrated metrology in semiconductor manufacture. The first sensor is a prototype system which uses two laser beams of different wavelength to module the surface temperature of a wafer. The ratio of detected thermal radiances at the two wavelengths is ideally independent of wafer emissivity. Initial measurements on differently-processed silicon wafers in the temperature range 620 - 1000 degree(s)C show systematic errors of the order 10 degree(s)C. The second sensor is a spectroscopic ellipsometry system fully integrated onto a low pressure chemical vapor deposition reactor for monitoring and controlling growth of silicon-germanium (SiGe) alloys. Algorithms for determining alloy composition and film thicknesses during growth are discussed. The use of a sample-based particle filter based on Bayesian statistics for tracking a semiconductor process is described for the first time.

Date Published: 23 April 1999
PDF: 7 pages
Proc. SPIE 3742, Process and Equipment Control in Microelectronic Manufacturing, (23 April 1999); doi: 10.1117/12.346246

Published in SPIE Proceedings Vol. 3742:
Process and Equipment Control in Microelectronic Manufacturing
Kevin Yallup; Murali K. Narasimhan, Editor(s)