Patent ID: 9563117
Date: 2017-02-07
CPC Classifications: G03F

Claim:
1. A mask assembly for performing double exposure on a negative-type development photoresist layer, the mask assembly comprising: a first mask comprising a plurality of first main features parallel to each other, a plurality of first sub-resolution assistant features, and a plurality of second sub-resolution assistant features, wherein the second sub-resolution assistant features are disposed separately from each other at one side of the first main features, the first sub-resolution assistant features are disposed separately from each other between the first main features and the second sub-resolution assistant features, and an extension direction of the first main features is parallel to an extension direction of the second sub-resolution assistant features; and a second mask comprising a plurality of second main features parallel to each other, wherein the second main features intersect with the first main features, and the second main features overlap with the first sub-resolution assistant features when the first mask and the second mask are placed at a predetermined position above the negative-type development photoresist layer for performing exposure respectively.