ASML Holding N.V.
Etch variation tolerant optimization

Abstract:

A method to improve a lithographic process for imaging a portion of a design layout onto a substrate using a lithographic projection apparatus and for transferring the imaged portion of the design layout to the substrate by an etching process, which method includes: determining a value of at least one evaluation point of the lithographic process for each of a plurality of variations of the etching process; computing a multi-variable cost function of a plurality of design variables that are characteristics of the lithographic process, wherein the multi-variable cost function is a function of deviation from the determined values of the at least one evaluation point; and reconfiguring the characteristics of the lithographic process by adjusting the design variables until a termination condition is satisfied. This method may reduce the need of repeated adjustment to the lithographic process when the etching process varies.