An optical linewidth measurement station for quality control of wafer production with respect to critical dimension and overlay registration measurements is described. An automatic wafer handler with slit scan photometer, fast scanning stage and pattern align ment module provide fast lot throughput with minimal contamination. A personal computer controls the system and stores measurement recipes and data Linewidths are extracted from high resolution optical intensity profiles using various line edge definitions. Automatic run data on a nominally 0.8 um wide and 2 um high Y-shaped structure of a stepped test pattern for various process levels such as resist on nitride, resist on metal and resist on silicide, are presented to demanstrate instrument positioning and measurement repeatability. The effect of a defined interlayer focus variation (steps from top to bottom of a structure) with a high speed focusing device is correlated to the measurenent results: Data from different types of measuring instruments is compared by linear regression analysis.

Date Published: 1 January 1988
PDF: 6 pages
Proc. SPIE 0921, Integrated Circuit Metrology, Inspection, and Process Control II, (1 January 1988); doi: 10.1117/12.968385

Published in SPIE Proceedings Vol. 0921:
Integrated Circuit Metrology, Inspection, and Process Control II
Kevin M. Monahan, Editor(s)