Patent ID: 6294295
Filing Date: 2001-09-25
Classification: G03F

Abstract:
A method of forming an attenuating phase shifting mask, comprising:providing a transparent mask substrate having a layer of attenuating phase shifting material formed on said transparent mask substrate and a layer of opaque material formed on said layer of attenuating phase shifting material, wherein said layer of attenuating phase shifting material has a first transmittance and provides a first phase shift;forming a first number of first holes and a second number of second holes in said layer of opaque material and said layer of attenuating phase shifting material;removing that part of said opaque material within a first width of the outer perimeter of said first holes and within a second width of the outer perimeter of said second holes, thereby exposing a first region of said attenuating phase shifting material surrounding each of said first holes and a second region of said attenuating phase shifting material surrounding each of said second holes;treating said second region of said attenuating phase shifting material with a first solution for a first time, thereby changing the transmittance of said attenuating phase shifting material in said second region to a second transmittance and the phase shift provided by said attenuating phase shifting material in said second region to a second phase shift; andtreating said second region of attenuating phase shifting material with a second solution for a second time, after treating said second region of attenuating phase shifting material with said first solution for said first time, thereby changing the transmittance of said attenuating phase shifting material in said second region to a third transmittance and the phase shift provided by said attenuating phase shifting material in said second region to said first phase shift.