Patterned implant metrology

摘要

A method (40) for nondestructively characterizing a doped region (24) of a semiconductor wafer (22) in order to determine the acceptability of a pattern transfer process. Of particular interest is the determination of the lateral profile of the implanted structure. An incident beam (28) of radiation is directed upon the wafer surface (26) and the properties of the resulting refracted beam (30) are measured as a function of wavelength. The spectrally-resolved diffraction characteristics of the refracted beam are directly related to the shape and scale characteristics of the doped region. A library (44) of calculated diffraction spectra is established by modeling a full range of expected variations in the doped region structures. The spectra resulting from the inspection of an actual doped region (46) is compared against the library to identify a best fit (48) in order to characterize the actual implant (50). The results of the comparison may be used as an input for upstream and/or downstream process control (52).