New photolithographic method for small dimension. Direct step and repeat technique (silicon repeater)

The direct step and repeat technique was investigated with a silicon repeater, designed for mask as well as slice illumination. The testing of this machine in connection with slice technology is emphasized, especially as to the automatic alignment system. The excellent optical performance and the high positioning and alignment accuracy were demonstrated with different semiconductor technologies. The automatic alignment system performs mask to wafer alignments within + or - 01 micron and overlays of different mask levels within + or - 0.25 micron. For the process evaluation, a comparison was made with a projection aligner.