Patent ID: 6660653
Filing Date: 2003-12-09
Classification: G03F,Y10S

Abstract:
A method for fabricating a dual-trench alternating phase shift mask (PSM) comprising:patterning an opaque layer over a transparent layer of the PSM according to a semiconductor design; first dry etching a first plurality of times the transparent layer through a first photoresist layer applied over the opaque layer and patterned according to the deep trenches of the alternating PSM design by using beam writing, to initially form deep trenches of the PSM; and, second dry etching a second plurality of times the transparent layer through a second photoresist layer applied over the opaque layer and patterned according to the shallow trenches and the deep trenches of the alternating PSM design by using backside exposure, to completely form shallow trenches and the deep trenches of the PSM.