Patent ID: 6304326
Filing Date: 2001-10-16
Classification: G01B,G01J,G01N

Abstract:
An apparatus for evaluating characteristics of a semiconductor test sample comprising:a measurement device module including a light source for generating a probe beam directed to reflect off the test sample and wherein the probe beam is focused so that rays within the probe beam strike the sample at a plurality of different angels of incidence and further including a detector for monitoring the changes in the intensity of the reflected probe beam as a function of angle of incidence;a processor for evaluating the test sample based on the measured changes of the probe beam; anda calibration module including a reference sample and an off-axis ellipsometer having a wavelength stable, narrowband light source for measuring the reference sample and wherein said apparatus is arranged so that the reference sample is also measured by the measurement device module and wherein the processor utilizes the measurements of the reference sample by both the off-axis ellipsometer and the measurement device module to calibrate the measurement device module for subsequent measurements of test samples.