Thickness Measurement Technology for Thin Films on Sapphire Substrate

Silicon-on-sapphire (SOS) integrated circuits are attracting attention due to their high speed performance and low power consumption. An important aspect of the SOS fabrication process that must be verified to maximize yield is the thickness of the thin films deposited on the sapphire substrate. However, due to the transparent nature of sapphire, current optical metrology tools are not applicable. Advanced Cooling Technologies, Inc. (ACT) proposes a Small Business Technology Transfer (STTR) Phase I program to develop and demonstrate an easy-to-use, non-contact and non-destructive, high resolution instrument for performing thin film and thin film stack thickness measurements for SOS devices. The proposed novel technique uses an alternative spectrographic technique to quickly and accurately determine thin film thicknesses with sub-nm accuracy. In the Phase I program, the feasibility of this technique will be proved through laboratory demonstration. In the Phase II program, the technique will be packaged into an instrument that can be integrated into an SOS wafer fabrication process.