Tadashi Ohtaka

Highly accurate CD measurement with a micro standard

Accurate measurement with CD-SEMs requires the use of a calibrated standard. A new standard, micro-scale was developed using laser interferometer lithography and anisotropic chemical etching on Si-material and was reported previously. In this paper, we report on a method to control measurement accuracy of CD-SEMs using the micro-scale. We have studied various factors for measurement errors and have estimated the 95 percent confidence level. We have carried out 3-pitch measurement of the micro-scale in a fully automated mode and estimated the 95 percent confidence level. Then, we compared two 95 percent confidence levels and concluded that the estimation expected from the measurement errors was reasonable.