Low-temperature 193-nm resist reflow process for 100-nm generation contact patterning

Manufacturable process windows for the small contact dimensions of the 100 nm lithography generation are well beyond the capability of current 193 nm resist and exposure tool processes. Even with next generation very high NA (>0.7) 193 nm exposure tools, simulations indicate that these contact sizes are not obtainable with standard processing techniques. Therefore, we have investigated the feasibility of using a 193 nm resist reflow technique to obtain small contact hole sizes. We have chosen the Thin Imaging System 2000 (TIS2000) of ARCH Chemicals for investigation. This resist provides good process latitudes and excellent etch selectivity and has a much lower Tg compared to single layer 193 nm resists. This work will show the impact of resist flow on Focus-Exposure windows, proximity and proximity-uniformity, CD-uniformity over the wafer and mask error factor. Additional experimental results will highlight profiles after oxide etch as well as process windows achievable with a 6% attenuated phase shift mask.