Enabling chemically amplified resists towards tight pitch EUV patterning by directed self-assembly (Invited Paper)

Moving into the era of EUV lithography, it is becoming increasingly difficult for traditional chemically amplified resist materials to meet the patterning requirements. In view of this, there is growing interest in alternative resist platforms or auxiliary patterning techniques such as directed self-assembly (DSA). By combining EUV lithography with DSA, dense line/space or hexagonal contact hole patterns can be rectified. As such, DSA can enable the use of CAR materials at increasingly tight pitch and acceptable EUV dose. In this talk, we will firstly discuss the rectification of pitch 24 nm line/space patterns. It will be shown how line edge roughness can be minimized by optimizing the etch and stack. Furthermore, we will touch upon the use of high-chi DSA materials for further roughness reduction. Finally, efforts to control the pattern placement error for pitch 30 nm hexagonal contact hole arrays will be presented.