In the very competitive international IC-market, companies are driven towards producing increasingly complex IC-designs at a constantly decreasing cost-per-function. This has been one of the major driving forces behind the continuous scaling down of the minimum device dimensions. Despite the increase in density obtained by this, the chip size has grown dramatically over the last years. Due to this trend, an economically feasible production could only be obtained by a continuous decrease in the defect density and process variability in order to obtain high process yields. Improvements in the Si-wafer quality, lowering of the process-induced contamination level and a tighter process control have, therefore, been key issues over the last years for companies in order to stay ahead of the competition. There is no doubt that the availability of better wafers and cleaner process materials (such as chemicals, DI water, and process gases) significantly contributed to the success and continuous growth of this industry.
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