Patent ID: 7274472

Claim:
A resolution enhanced optical metrology system to examine a structure formed on a side of a semiconductor wafer, the system comprising: a source configured to direct an incident beam at the structure, wherein the incident beam has a wavelength; a coupling element configured to be disposed between the source and the structure with the coupling element facing the side of the semiconductor wafer on which the structure is formed, wherein a gap, having a gap height, is defined between the coupling element and the structure when the coupling element is disposed between the source and the structure, and wherein the wavelength of the incident beam is greater than the gap height; and a diffractive element configured to disperse the incident beam, wherein the diffractive element is disposed between the coupling element and the structure, wherein the diffractive element has a pitch, wherein the structure has a pitch, and wherein the pitch of the diffractive element is adapted to the pitch of the structure.