Method of patterning

A method of patterning to obtain a prescribed pattern in a substrate, the prescribed pattern having one or more first edges in a first direction and one or more second edges in a second direction, the first edges and the second edges forming corners of the prescribed pattern, the method comprising:

• dividing the prescribed pattern into a first pattern forming one or more of the first edges and a second pattern forming one or more of the second edges;
• forming a first mask layer over the substrate;
• forming a second mask layer over the first mask layer;
• forming the second pattern over the second mask layer;
• removing a first portion of the second mask layer using the second pattern;
• forming the first pattern over the first mask layer, at least a portion of the second pattern overlapping the first pattern to form the corners of the prescribed pattern;
• removing a portion of the first mask layer exposed through the second mask layer to expose a portion of the substrate;
• and
• etching the substrate exposed through the first mask layer and the second mask layer to obtain the prescribed pattern.

A method of reducing corner rounding during patterning of a substrate to form a prescribed pattern comprising a corner, the method comprising:

• dividing the prescribed pattern into a first pattern and a second pattern, the first pattern forming a first edge of the corner and the second pattern forming a second edge of the corner, wherein at least a portion of the second pattern overlaps the first pattern such that the first edge intersects with the second edge to form a first corner of the prescribed pattern;
• forming the first pattern in a first mask layer disposed over a substrate to expose the substrate;
• forming the second pattern in the first mask layer to expose the substrate;
• and
• etching the substrate exposed through the first mask layer to obtain the prescribed pattern.