Abstract

A method of using scatterometric techniques to control stepper process is disclosed. In one illustrative embodiment, the method comprises providing a library of optical characteristic traces, each of which corresponds to a grating structure comprised of a plurality of photoresist features having a known profile, and forming at least one grating structure in a layer of photoresist, wherein the formed grating structure is comprised of a plurality of photoresist features having an unknown profile. The method further comprises illuminating the formed grating structure, measuring light reflected off of the formed grating structure to generate an optical characteristic trace for the formed grating structure, comparing the generated optical characteristic trace to at least one optical characteristic trace from the library, and modifying at least one parameter of a stepper exposure process to be performed on at least one subsequently processed wafer based upon the comparison of the generated optical characteristic trace and the optical characteristic trace from the library. In another embodiment, the generated optical characteristic trace for the grating structure is compared to a target optical characteristic trace for the grating structure, and at least one parameter of an exposure process to be performed on a layer of photoresist formed on a subsequently processed wafer may be determined or modified based upon this comparison.