PLASMA-ETCHING OF SUBMICRON DEVICES - IN-SITU MONITORING AND CONTROL BY MULTIWAVELENGTH ELLIPSOMETRY

We show that the use of in situ multi-wavelength ellipsometry allows e ndpoint detection during the plasma etching of submicron devices in a high-density plasma reactor. In addition, a quantitative model is pres ented to understand the ellipsometry traces obtained while etching pat terned wafers. It allows one to determine the thickness of a film in r eal-time as it is etched. Knowing the thickness in real-time allows gr eater process control, as it enables one to stop or change the process at a specified remaining film thickness. This is extremely useful in the context of device fabrication, since processing conditions can be adjusted in real-time. (C) 1998 Published by Elsevier Science S.A.