The new evaluation method has been developed for the practical resolution of reduction optics by applying the quantitative value of resolution index and the accurate evaluation results are obtained. The quantitative value of Resolution Index is defined as the controllability of critical dimension and this value for the arbitrary pattern represents the resolution of reduction optics. The critical dimension of the resist pattern is altered by the focus position and exposure dose and the characteristic curve is obtained by this relationship. This characteristic curve will also express the allowable range to the defocusing and exposure dose for the critical dimension control and this range is determined by the resolution capability of given optics. The concept of this method is that the exposure and focus tolerance are simultaneously determined by defining allowable CD tolerance of the arbitrary pattern and the Resolution Index is obtained by calculating the defined area on the two dimensional coordinate of focus-exposure dose plane. The calculation of Resolution Index is very simple because the relationship of focus-exposure dose is expressed by the simplified equation. In this paper, the basic concept of this quantitative evaluation method; characterization of CD curves; application to the full exposure field; detail of the calculation procedure for the resolution index; practical resolution limit will be discussed.

Date Published: 25 July 1989
PDF: 12 pages
Proc. SPIE 1088, Optical/Laser Microlithography II, (25 July 1989); doi: 10.1117/12.953141

Published in SPIE Proceedings Vol. 1088:
Optical/Laser Microlithography II
Burn Jeng Lin, Editor(s)