In this paper we address keystone error, a significant parameter when diagnosing the misalignment of projection optics in maskless lithography systems. Tilting of either the object or image planes of an optical system results in keystone error. In this experiment, we measure the position of a 15×15 beam spot array with an accuracy of 100 nm. We numerically fit the measured position of the beam spot array into a theoretical model to determine the keystone error of the projection optics in a maskless lithography system. Using this method, we align the optical system to minimize the keystone error to 0.01% with a 1.5×1.5 mm2 square object. We also analyze the influence of the keystone error on the stitch error.
|Number of pages
|International Journal of Precision Engineering and Manufacturing
|Published - 2015 Feb
Bibliographical notePublisher Copyright:
© 2015, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Industrial and Manufacturing Engineering
- Electrical and Electronic Engineering