Abstract: A calibration device applied for a test apparatus with at least a first probe and a second probe, the calibration device comprising: a first testing region and a second testing region, the first testing region and the second testing region divides into n×n sensing units respectively, the first testing region for generating n×n average electricity corresponding to a contact degree of the first probe contacted with the calibration device, and the second testing region for generating another n×n average electricity corresponding to a contact degree of the second probe contacted with the calibration device, and the pitch is the distance between the center of the first testing region to the center of the second testing region that is the same as that of the center of the first probe to the center of the second probe.

Abstract: A method for characterizing line width roughness of printed features is provided. A wafer having thereon a plurality of gratings formed within a test key region is prepared. The wafer is transferred to a spectroscopic ellipsometry tool having a light source, a detector and a computer. A polarized light beam emanated from the light source is directed onto the gratings. Spectrum data of reflected light is measured and recorded. The spectrum data is compared to a library linked to the computer in real time. The library contains a plurality of contact-hole model based spectra created by incorporating parameter values that describes the line width roughness. The spectrum data is matched with the contact-hole model based spectra, thereby determining the parameter values.