Study of mask structure for 45-nm node based on manufacturability and lithographic performance

As design rule has decreased, blank type or photo resist, which meets requirement of resolution, has been developed. HT PSM mainly used to pattern small line width has no longer advantages for immersion wafer process. It makes binary mask to be gradually used for mask production. Comparing to HT PSM, the production of binary mask has a relatively simple process. However, we may consider optical density, PR or Cr thickness, etch selectivity, and ID bias related to linearity for applying binary mask below sub-45nm. In this paper, we will compare and analyze difference between actual manufacture and theoretical optic level such as optical density. Finally, based on our experiment, optimal combination of photoresists and blanks which can realize sub-45nm node will be discussed.