PROXIMITY EFFECT CORRECTION FOR 1/1 X-RAY MASK FABRICATION

This article describes the improvement of a sell-consistent proximity effect correction to fabricate 1:1 X-ray masks. The present method has two features; the first is the change of sampling point from pattern edges to the center. This is effictive in saving on the calculation time, and it is theoretically shown that the deposited energy intensity at the edge is equal to that obtained with the conventional method. The other is to combine the pattern shape and additional dose modulations for finer patterns less than or equal to 4 beta(f), beta(f) is the forward scattering range of electrons) with the ordinary dose modulation method. The algorithm is verified by experiments and simulations, and is found to be effective in reproducing 0.1 mu m patterns with high accuracy.