Patent ID: 6094256
Filing Date: 2000-07-25
Classification: G03F

Abstract:
A method of forming a critical dimension test structure (CDTM) image comprising:providing an exposure system having an image plane and an object plane;providing an image forming layer overlying a substrate disposed in said image plane, said image forming layer requiring a nominal exposure energy to form an image;providing a first feature disposed in said object plane wherein said first feature has a first orientation and a first critical dimension;projecting said first feature onto said image forming layer at a first exposure energy less than the nominal exposure energy; andproviding a second feature disposed in said object plane wherein said second feature has a second orientation and a second critical dimension;projecting said second feature onto said imaging forming layer at a second exposure energy less than the nominal energy wherein a doubly exposed region in said image forming layer is formed where said first feature and said second feature overlap, said doubly exposed region being exposed with a total exposure energy approximately equal to the nominal exposure energy; andforming said CDTM image in said image forming layer, the CDTM image comprising said doubly exposed region, and having a dimension representative of the average of the first critical dimension and the second test critical dimension.