The tight overlay budgets required for 45nm and beyond makes overlay control a very important topic. High order overlay control (HOC) is becoming an essential methodology to remove the immersion induced overlay signatures. However, to implement the high order control into dynamic APC system requires FA infrastructure modification and a stable mass production environment. How to achieve the overlay requirement before the APC-HOC system becomes available is important for RD environment and for product early ramp up phase. In this paper authors would like to demonstrate a field-by-field correction (FxFc) or correction per exposure (CPE) methodology to improve high order overlay signature without changing current APC-linear control system.

Date Published: 1 April 2010
PDF: 8 pages
Proc. SPIE 7638, Metrology, Inspection, and Process Control for Microlithography XXIV, 76382K (1 April 2010); doi: 10.1117/12.846569

Published in SPIE Proceedings Vol. 7638:
Metrology, Inspection, and Process Control for Microlithography XXIV
Christopher J. Raymond, Editor(s)