Characterisation of mirror-polished Si wafers and advanced Si substrate structures using the magic mirror method

Abstract

Makyoh, the magic mirror method, has proven to be one of only a few production-worthy surface characterisation tools. This technique, very simple and non-destructive, transforms latent damage, scratches, waviness and other flaws on mirror-like surfaces into visual images. It has recently been used to characterise highly finished, mirror-polished, large-diameter Si wafers for ultralarge-scale integration (ULSI) applications and III-V compound semiconductor wafers, replacing the laborious, unstable, naked-eye wafer inspection line. The authors studies have shown that the technique is also very useful for optimising various wafering processes and monitoring various process steps required to manufacture advanced substrate structures such as silicon-on-insulator, silicon-germanium alloy-on-silicon, etc for future devices. It has been successfully applied to characterise various Si wafers used in ULSI applications with the highest finish. This paper describes the recent development of the method, reviewing some of the results obtained in the evaluation of mirror-polished Si and compound semiconductor wafers and of complex substrate structures for ULSI device fabrication processes.