The strong smoothing effect resulting from recent progress in multilayer deposition technology has a great influence on the imaging characteristics of mask blank defects. The imaging characteristics of such defects were investigated through accurate simulations employing the FDTD method; and the effect of multilayer smoothing on the aerial image was examined. Strong smoothing was found to suppress the degradation in the aerial image due to phase defects while at the same time giving rise to phase defects that are undetectable iwth a visible-light inspection tool. 3-dimensional simulations also indicated the existence of such defects. Moreover, the aerial image of phase defects after repair with an electron beam was also investigated. Repair was found to be effective when there was no smoothing, but not so effective when there was strong smoothing. Experimental verification of these results will be attempted in the near future.

Date Published: 20 May 2004
PDF: 11 pages
Proc. SPIE 5374, Emerging Lithographic Technologies VIII, (20 May 2004); doi: 10.1117/12.534692

Published in SPIE Proceedings Vol. 5374:
Emerging Lithographic Technologies VIII
R. Scott Mackay, Editor(s)