Speculation on the EUV photoresist behavior at different dose and pitch

Abstract

Strong challenge on EUV photoresist includes overcoming the stochastic effect caused by the lack of photons. At the different dose range, the relationship of LCDU and dose moves differently. This ‘breaking point’ in the relationship of LCDU and dose is measured at different pitches with photoresists and masks with different uniformity. Smaller pitch patterning requires more dose, whereas photoresist and mask does not affect the ‘breaking point.’ Combining these speculations show the limitation of the EUV at the low dose process, which is critical for high volume manufacturing.