Paul van Gerven
23 February

This week at the 2021 SPIE Advanced Lithography Conference, Imec and ASML present several papers that demonstrate the ultimate single-exposure patterning capability of today’s most advanced 0.33 NA EUV scanner, the NXE:3400. Process optimizations have enabled the patterning of dense 28nm pitch line/spaces in one single exposure, which corresponds with critical metal layers at the 5nm node. “This brings the NXE:3400 scanner very close to its resolution limit for high-volume manufacturing,” says Kurt Ronse, advanced patterning director at Imec.

Imec 28nm pitch
28nm pitch single-exposure patterning on a 0.33NA EUV full-field scanner after Ru metallization.

The partners also implemented source optimizations to print the smallest pitch possible with the current NXE:3400 model: 24nm pitch line/spaces and 28nm pitch contact holes. Reaching this extreme resolution will “provide the Imec patterning ecosystem with the opportunity to develop resist, metrology and etch processes to accelerate the introduction of the next-generation EUVL system, ie the high-NA EXE:5000,” comments CEO Andrew Grenville of Inpria, the company that supplied the resist for the challenging exposures.

Previously, also to get a head start on high-NA patterning, Imec reported printing a 20nm pitch line/space pattern using high-NA interference lithography. The research institute expects to be able to go down to 8nm pitch with this technique.