Extreme ultraviolet lithography
Extreme ultraviolet lithography (also known as EUV or EUVL) is a next-generation lithography technology using an extreme ultraviolet (EUV) wavelength, currently expected to be 13.5 nm. EUV is currently targeted for possible future use below 15 nm resolution after the 7 nm node, in 2018-2019. The primary EUV tool maker, ASML, projects EUV at 5 nm node to require a higher numerical aperture than currently available and multiple patterning to a greater degree than immersion lithography at 20 nm node. It was first targeted for 100 nm conventional patterning. While source power is the chief concern due to its impact on productivity, significant changes in mask infrastructure, including blanks, pellicles and inspection, are also under study. Particle contamination would be prohibitive if pellicles were not stable above 200 W, i.e., the targeted power for manufacturing. Without pellicles, particle adders would reduce yield, which has not been an issue for conventional optical lithography with 193 nm light and pellicles.