Abstract
EUV lithography will be used as high volume manufacturing of semiconductor devices after 2020, where the half pitch of the devices is 10 nm. EUV interference lithography (EUV-IL) has been developed for the EUV resist evaluation with 10-nm and below patterning. The transmission grating is a key component for EUV-IL. The pitch size of the interference fringes are half size of the absorber pattern of the transmission grating. In this paper, diffraction grating pattern with 20-nm line-and-space pattern with very high aspect of 90-nm carbon layer was fabricated using the dry development rinse (DDR) process with spin-on-carbon under-layer. The diffraction efficiency of the grating is expected to be 6%, which is enough for EUV-IL. In the DDR process, the DDR material replaced the exposed and developed part. The DDR process with dry development is to prevent pattern collapse perfectly because there is no surface tension at the dry development process. As the results, 20-nm L/S pattern with high-aspect-ratio of 5.9 was fabricated, which can be applied for the 10-nm EUV resist evaluation by EUV-IL.
