Patent ID: 6458495
Filing Date: 2002-10-01
Classification: G03F

Abstract:
A method of fabricating a phase-shifting mask for use with a light at a wavelength comprising:a substrate formed from a transparent material, said substrate having a first thickness, said substrate comprising a first region, a second region, and a third region, forming an opaque layer on said substrate, using a first etch to remove said opaque layer in said first region and said second region, using a second etch to form a trench in said first region, said trench having an upper width and a lower width, and using a third etch to make said lower width larger than said upper width and to reduce said substrate in said first region to a second thickness, such that said light at said wavelength transmitted through said first region is shifted in phase by 180 degrees relative to said light at said wavelength transmitted through said second region.