Patent ID: 6274281
Filing Date: 2001-08-14
Classification: G03F

Abstract:
A contact hole mask, comprising:a transparent mask substrate having a first number of first contact hole regions and a second number of second contact hole regions wherein each of said first contact hole regions have a first width and a first outer perimeter and each of said second contact hole regions have a second width and a second outer perimeter;a first thickness of light absorbing material formed on that part of said transparent mask substrate not covered by said first number of first contact hole regions and said second number of second contact hole regions, wherein said first thickness of said light absorbing material has a first transmittance;a second thickness of said light absorbing material formed on each of said first contact hole regions of said transparent mask substrate, wherein said second thickness of said light absorbing material has a second transmittance; anda third thickness of transparent phase shifting material formed on said first thickness of said light absorbing material covering that part of said transparent mask substrate not covered by said first number of first contact hole regions and said second number of second contact hole regions, wherein said third thickness of said transparent phase shifting material produces a phase shift of 180.degree..