Patent ID: 8626328
Filing Date: 2014-01-07
Classification: G03F,G05B,H01L

Abstract:
1. A method for dynamically controlling variation during an exposure step of a patterning process using an exposure tool comprising: measuring a set of one or more pattern attributes at a set of discrete locations on a substrate, the substrate having two or more fields and at least one field having two or more of the set of discrete locations; selecting a first set of basis functions representing a first variation of the set of one or more pattern attributes over a first set of discrete locations within a first field, and selecting a second set of basis functions representing a second variation of the set of one or more pattern attributes over a second set of discrete locations within a second field; defining a first set of reference locations within a field; defining a second set of reference locations over the substrate; constructing a first orthogonal set of functions from the first set of basis functions on the first set of reference locations and constructing a second orthogonal set of functions from the second set of basis function on the second set of reference locations; and constructing a third orthogonal set of basis functions comprised of the first set of basis functions and the second set of basis functions and the product of each of the first set of basis functions with each of the second set of basis functions; fitting the third orthogonal set of functions to the measured set of one or more pattern attributes at the set of discrete locations; determining, as a result of said fitting, a set of coefficients of the third orthogonal set of functions; and minimizing a variation in the one or more pattern attributes by adjusting the exposure tool or the patterning process according to one or more said determined set of coefficients.