Variable transmittance phase shifter to compensate for side lobe problem on rim type attenuating phase shifting masks

A method of exposing a pattern in a layer of photosensitive dielectric material, comprising:

• providing a phase shifting mask having a first pattern comprising a first number of transparent first holes having a first width;
• said first number of first rims surrounding each of said first holes, wherein each of said first rims is formed of a first attenuating phase shifting material having a first transmittance and provides a first phase shift to light passing through said first rims relative to light passing through said first holes;
• a second number of transparent second holes having a second width;
• said second number of second rims surrounding each of said second holes, wherein each of said second rims is formed of a second attenuating phase shifting material having a second transmittance and provides said first phase shift to light passing through said second rims relative to light passing through said second holes;
• and opaque material formed on those regions of the mask not covered by said first holes, said first rims, said second holes, or said second rims;
• providing a photolithographic exposure system comprising a wafer holder, a mask holder, and an illumination system having a numerical aperture and a sigma;
• providing a wafer having a layer of photosensitive dielectric material formed thereon;
• exposing said pattern on said layer of photosensitive dielectric material with light from said illumination system using said mask and said photolithographic exposure system;
• and
• developing said photosensitive dielectric material.

A phase shifting mask, comprising:

• a first number of transparent first holes having a first width, wherein said first holes have a first duty ratio wherein said first duty ratio is equal to the distance between the outer perimeter of adjacent said first holes divided by said first width;
• said first number of first rims surrounding each of said first holes, wherein each of said first rims is formed of a first attenuating phase shifting material having a first transmittance and providing a first phase shift to light passing through said first rims relative to light passing through said first holes;
• a second number of transparent second holes having a second width, wherein said second holes have a second duty ratio wherein said second duty ratio is equal to the distance between the outer perimeter of adjacent said second holes divided by said second width;
• said second number of second rims surrounding each of said second holes, wherein each of said second rims is formed of a second attenuating phase shifting material having a second transmittance and providing a second phase shift to light passing through said second rims relative to light passing through said second holes;
• and
• opaque material formed on those regions of the mask not covered by said first holes, said first rims, said second holes, or said second rims.