Abstract: As photolithography technology advances into submicronregime, the requirement for alignment accuracy alsobecomes much tighter. The alignment accuracy is afunction of the strength of the alignment signal.Therefore, a detailed alignment signal intensitysimulation for 0.8 $mu@m EPROM poly-1 layer on ASMstepper was done based on the process of record in thefab to reduce misalignment and improve die yield. Oxidethickness variation did not have significant impact onthe alignment signal intensity. However, poly-1thickness was the most important parameter to affectoptical alignments. The real alignment intensity dataversus resist thickness on production wafers wascollected and it showed good agreement with thesimulated results. Similar results were obtained forONO dielectric layer at a different fab.!7
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