This paper presents the result of a new algorithm designed to improve the success rate, precision and accuracy of the measurements for low contrast targets produced by STI. The paper will also review the algorithm and discuss the result of target design optimization. Results will be provided from multiple lots with multiple wafer analysis demonstrating the effectiveness of the algorithm. Measurement yields improve from the 35 percent-50 percent success rate using current algorithms to 99 percent-100 percent success rate using the new algorithm. Precision was improved from 10nm to 3nm, and as low as 1.2 nanometers 3(sigma) . The true success of the algorithm is not just the improved measurement success, precision and accuracy; but it is in the verification that the edges are detected and measured accurately. Many current algorithms are giving estimates.

Date Published: 14 June 1999
PDF: 7 pages
Proc. SPIE 3677, Metrology, Inspection, and Process Control for Microlithography XIII, (14 June 1999); doi: 10.1117/12.350798

Published in SPIE Proceedings Vol. 3677:
Metrology, Inspection, and Process Control for Microlithography XIII
Bhanwar Singh, Editor(s)