Method of aligning a mask in photolithographic process

A method for aligning a mask in a photolithographic process, comprising the steps of:

• (1) providing the mask with an opaque frame having four corners;
• (2) forming a plurality of alignment patterns on a platform where the mask is to be placed, said alignment patterns including:
• a plurality of parallel-spaced first bars and a plurality of parallel-spaced second bars disposed on the platform and oriented in a first direction, wherein at least two of said first bars and two of said second bars are separated by a distance equal to the width of said opaque frame, allowing the mask to be positioned by alignment therebetween;
• and
• a plurality of parallel-spaced third bars and a plurality of parallel-spaced fourth bars disposed on the platform and oriented in a second direction at a right angle with respect to the first direction, wherein at least two of said third bars and two of said fourth bars are separated by a distance equal to the width of said opaque frames allowing the mask to be positioned by alignment therebetween;
• and
• (3) performing an alignment of the mask by visually checking for misalignment of the mask with reference to the alignment patterns on the platform.

A method for aligning a mask in a photolithographic process comprising the steps of:

• (1) providing the mask with an opaque frame having four corners;
• (2) forming a plurality of alignment patterns on a platform where the mask is to be placed, said alignment patterns including:
• at least two parallel spaced first bars and at least two parallel spaced second bars disposed on the platform in oriented in a first direction, wherein in the at least two said first bars and the at least two said second bars are separated by a distance equal to the width of said opaque frame, allowing the mask to be positioned by alignment between two of the first bars and two of the second bars;
• and
• (3) performing an alignment of the mask by visually checking for misalignment of the mask with reference to the alignment patterns of the platform.