Patent ID: 8288064

Claim:
A method for examining at least one wafer with regard to a contamination limit, comprising: examining a contamination potential of a resist of the wafer, which resist outgasses contaminating substances, in an examining location; transferring the wafer from the examining location directly to an exposure location if the contamination potential falls below the contamination limit; and exposing the wafer at the exposure location in a projection exposure system that operates in an extreme ultraviolet wavelength range, wherein said examining comprises: arranging the wafer in a vacuum chamber comprising the examining location, evacuating the vacuum chamber, and measuring the contamination potential of the contaminating substances outgassed from the resist in the evacuated vacuum chamber, heating the wafer to an elevated temperature only if the contamination potential exceeds a contamination limit; further measuring the contamination potential of the contaminating substances outgassed from the resist during said heating; and maintaining the wafer at at least the elevated temperature until, based on said further measuring, the contamination potential falls below the contamination limit.