In this work, an Amphibian XIS interference mini-stepper is used to synthesize the aerial image of 90nm dense line/space pattern produced by an ASML TWINSCAN /1150i immersion scanner, using a second single beam exposure to demodulate the first 100% modulated interference exposure. The experimental data from the scanner and the demodulated interference exposure have near identical exposure latitude and LER (line edge roughness). Whilst the synthetic defocus data also shows a good degree of correlation with the projection data, the level of agreement is a little lower. Overall agreement is good, suggesting that the use of the synthetic aerial image approach is a useful screening tool for photoresists prior to testing on full field scanner system. This technique can be used to predict the performance of future projection tools, allowing cycles of learning in resist development prior to scanner availability.
Date of creation, presentation, or exhibit
Department, Program, or Center
Microelectronic Engineering (KGCOE)
Robertson, Stewart; Leonard, Joanne; Smith, Bruce; and Bourov, Anatoly, "Comparison of immersion lithography from projection and interferometric exposure tools" (2006). Accessed from
RIT – Main Campus