One of the most dramatic effects that one encounters when attempting tI optical imaging of 0.5k1 ASIC gate levels is the truncation or shortening of transistor geometries. This reduces the wafer process latitude and in some cases even eliminates the level..to-level overlay margin. We investigate a number of techniques, including varic*is complexities of mask cxnpensaüon and modified illumination to mitigate this phenomenon in manners sufficiently general to accommodate ASIC layouts.

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A field experiment has been installed near Firebaugh in the San Joaquin Valley of California to test submergence of drains as a means of denitrification of ground water. Laboratory and field experiments have shown that denitrification occurs in saturated soil where there is ample organic carbon available for bacterial metabolism. Denitrification and dilution of high nitrate ground water were accomplished in the field.