For achieving more accurate overlay measurement of optical metrology system, this paper shows a new approach from the viewpoint of measured data correlation between before and after etching. From this comparison, two new methodologies are proposed. One method does not require measurement after etching to optimize measurement algorithms. The superiority of this approach is also discussed compared to the criteria of measurement repeatability and TIS. Using the new methodologies, measurement algorithms are optimized for many kinds of processed wafers, including high temperature sputtered aluminum, with a grainier surface than conventionally sputtered aluminum.

Date Published: 4 August 1993
PDF: 11 pages
Proc. SPIE 1926, Integrated Circuit Metrology, Inspection, and Process Control VII, (4 August 1993); doi: 10.1117/12.148968

Published in SPIE Proceedings Vol. 1926:
Integrated Circuit Metrology, Inspection, and Process Control VII
Michael T. Postek, Editor(s)