Method for forming micro-lens array and photomask therefor

A method for forming a micro-lens array comprising:

• forming a hard-mask layer
• performing a lithography process on the hard-mask layer by a photomask to form a first pattern and a plurality of second patterns, and
• reflowing the first pattern and the plurality of second patterns to form a first lens structure and a plurality of second lens structures respectively,
• wherein the photomask comprises:
• a first transparent region;
• a first pattern segment corresponding to the first pattern;
• and
• a plurality of second pattern corresponding to the plurality of second patterns respectively,
• wherein the first pattern segment and the plurality of second pattern segments are separated by a plurality of portions of the first transparent region, the plurality of second pattern segments surround the first pattern segment, and a shape of the first pattern segment is different from a shape of each of the plurality of second pattern segments.