Patent ID: 8187774
Filing Date: 2012-05-29
Classification: B82Y,G03F

Abstract:
1. A mask for extreme ultra violet (EUV) lithography, comprising: a mirror layer that reflects EUV light incident on a substrate; an absorber pattern formed on the mirror layer to expose a first region and a second region in the mirror layer; a first groove formed by recessing a third region in the first region of the mirror layer by a first depth and a second groove formed by recessing a fourth region in the second region of the mirror layer by a second depth, which is deeper than the first depth whereby the first groove has a step with a surface of an exposed-edge portion of the first region, wherein the third region has a narrower width than the first region; and a second groove formed by recessing a fourth region in the second region of the mirror layer by a second depth whereby the second groove has a step with a surface of an exposed-edge portion of the second region, wherein the second groove is deeper than the first depth and the fourth region has a narrower width than the second region.