Infrared spectroscopy for process control and fault detection of advanced semiconductor processes

Abstract

Fourier transform infrared (FTIR) spectroscopy has emerged as an attractive sensor for in-situ monitoring and control of semiconductor fabrication processes. New applications are being enabled by advances in FTIR hardware and software that provide for: compact size, fast measurements with exceptional stability and signal to noise, and intelligent model based algorithms for thin film and gas analysis. In previously reported work, FTIR instrumentation with automated spectral analysis software was demonstrated as a novel sensor for monitoring layer properties such as thickness, composition and temperature. Recent work has emphasized applications to practical problems in modem semiconductor manufacturing. In this paper we will report pioneering results on: 1) Run-to-run closed loop control of a single wafer epitaxial silicon process using integrated infrared thickness and doping profiling metrology, 2) Fault detection during cluster tool plasma etching using real-time infrared exhaust gas analysis, and 3) oxygen implantation process monitoring during the formation of silicon on insulator (SOI) wafers using infrared reflectometry.