Patent ID: 7811720

Claim:
A photomask set for forming a single pattern in a device level of a semiconductor device, said photomask set comprising: a first mask usable to form a first pattern that is transferable to a device layer; and a second mask usable to form a second pattern that is transferable to said device layer and alignable with said first pattern to combine to form said single pattern that includes at least one substantially orthogonal corner formed of a first edge defined by said first pattern and a substantially orthogonal second edge defined by said second pattern, wherein said first mask is usable to form said first pattern in a first photoresist film that is transferable by a pattern transfer operation into said device layer and said second mask is usable to form a second pattern in a second photoresist film that is transferable by said pattern transfer operation into said device layer, said first photoresist film and said second photoresist film being the same photoresist film type, said photoresist film type being one of positive and negative.