Translator Disclaimer
14 June 1999 Understanding optical end of line metrology
Author Affiliations +
Optical end of line metrology, OELM, is a new method to measure relative line shortening effects using conventional optical overlay instruments. In this technique, a frame which has two adjacent sides that are constructed of lines and spaces is imaged onto a wafer. Since sub 0.5 micrometers gratings cannot be resolved using conventional optics,the alignment tool sees the sides compared of lines and spaces as solid edges. The purpose of this paper is to characterize errors implicit with this approach. First we show a general error analysis for determining best focus using OELM measurements. From this, we introduce the concept of local image quality as the inverse of the minimum lien shortening, and curvature of line shortening with focus.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David H. Ziger and Pierre Leroux "Understanding optical end of line metrology", Proc. SPIE 3677, Metrology, Inspection, and Process Control for Microlithography XIII, (14 June 1999);

Back to Top