Linnik microscope imaging of integrated circuit structures

Experimental one-dimensional intensity and phase images of thick (>200 nm) oxide lines on silicon are presented together with profiles predicted from the waveguide model. Experimental results were obtained with a purpose-built Linnik interference microscope that makes use of phase-shifting interferometry for interferogram analysis. Profiles have been obtained for both TE and TM polarizations for a wide range of focal positions and in both bright-field [type 1(a)] scanning and confocal modes of microscope operation. The results show extremely good agreement despite several simplifying assumptions incorporated into the theoretical model to reduce computing times.