We quantitatively evaluate Nuflare’s latest resist charging effect correction (CEC) model for advanced photomask production using e-beam lithography. Functionality of this CEC model includes the simulation of static and timedependent charging effects together with an improved calibration method. CEC model calibration is performed by polynomial fitting of image placement distortions induced by various beam scattering effects on a special test design with writing density variations. CEC model parameters can be fine tuned for different photomask blank materials facilitating resist charging compensation maps for different product layers. Application of this CEC model into production yields a significant reduction in photomask image placement (IP), as well as improving photomask overlay between critical neighbouring layers. The correlations between IP improvement facilitated by this CEC model and single mask parameters are presented and discussed. The layer design specifics, resist and blank materials, coupled with their required exposure parameters are observed to be the major influences on CEC model performance.

Date Published: 8 October 2014
PDF: 11 pages
Proc. SPIE 9235, Photomask Technology 2014, 92350Z (8 October 2014); doi: 10.1117/12.2066126

Published in SPIE Proceedings Vol. 9235:
Photomask Technology 2014
Paul W. Ackmann; Naoya Hayashi, Editor(s)