Evaluation of automated spectroscopic ellipsometry for in-line process control - ESPRIT semiconductor equipment assessment (SEA) project 'IMPROVE'

The performance of an automatic spectroscopic ellipsometer, the SOPRA Multi-layer Monitor (MLM) has been evaluated over a 1-year period on representative CMOS/Bipolar wafer structures supplied by IC manufacturers. Precision, stability, throughput, and accuracy where possible, have been assessed for ONO, OPO, oxide, Si/SiGe and PECVD oxide/metal wafers. Examples are given to illustrate the ability of the MLM to discriminate variations due to intrinsic and deliberately-induced process changes, as well as cross-wafer uniformity. Crown Copyright (C) 1998 Published by Elsevier Science S.A.