Improving semiconductor yields by varying silicon substrate parameters

An experiment to determine the impact on wafer probe and fabrication yields of systematically varying silicon substrate parameters within current specification ranges is discussed. The effect of parametric splits of three relevant silicon parameters on device probe yields were investigated. The parameters that were chosen were resistivity, interstitial oxygen content, and backside condition of p-type silicon wafers with a (100) orientation. The results are used to highlight ranges within the current specifications where improved yield could be expected. Yield benefits are then evaluated against the new costs of silicon substrates on this product. The experiment has shown that the effects of raw materials can play a significant role in impacting such key variables as device and fabrication yields