Abstract

A high resolution scanned laser microscope has been developed for integrated circuit metrology. This technology permits accurate measurement of the submicron features encountered in today’s VLSI devices. The dependence of measurement data on variables such as substrate layer type, topography, and reflectivity is typically a severe problem in conventional systems. The system described is entirely under computer control. In particular, it is possible to control focus in such a way that the high degree of surface topography encountered in IC devices causes no degradation of the measurement performance. This level of automation allows measurements which would be impossible in a purely manual machine. Results are presented that show how specimen reflectivity and surface topography may be separately determined. Measurements obtained from both test structures and production wafers are presented.

© 1985 Optical Society of America