Comparison of effects from wafer backside films on temperature uniformity in dual side lamp heated production RTP systems

This paper compares the temperature uniformity of the AST2000 (with and without HotLiner) and the Mattson 2900 6" production RTP tools. The vehicle for this evaluation is boron implanted poly pilot wafers with different backside stacks that are typical for CMOS IC fabrication. Differences and variations in the wafer backsides is a critical issue that has to be effectively dealt with in a production fab environment. Effects in wafer backside variations manifests in two ways. The first case is the effect that variations in monochromatic emissivity have on accuracy in pyrometry temperature measurement. The second case is the broadband emissivity effects on across wafer temperature uniformity. Data is presented on how the selected backside layers affect both of the above stated cases. Additional data is provided on the 2900 uniformity and repeatability.