Japans ASET researches EUV litho

11/01/1998

Japan`s ASET researches EUV litho

In a move that may suggest a broadening of enthusiasm for extreme UV lithography technology, Japan`s government-funded Advanced Semiconductor Equipment Technology (ASET) organization has begun a program that will bring a group of about 30 researchers together to concentrate on EUV. Stepper vendor Nikon will be a leading participant.

Heading the program will be Shinji Okazaki, a widely respected lithography specialist from Hitachi. Research headquarters will be at ASET`s Atsugi Research Center, Atsugi, about 50 miles west of Tokyo. Branch facilities will be set up at Nikon`s Sagamihara Works, where advanced steppers are designed and built, and at Himeji Institute of Technology, one of Japan`s national colleges.

Participating firms in the first stage will be Hitachi, Fujitsu, Sharp, Toshiba, NEC, Matsushita, Sony, and Nikon, all of whom will provide research personnel. Additional companies, including Mitsu-bishi, Oki, and others, are expected to join next April, at the beginning of the new fiscal year. The total research staff will number about 30.

Most of Japan`s post-optical efforts have until now been focused on x-ray and e-beam. ASET has conducted a feasibility study of lithography techniques, and come to the following conclusions:

193-nm ArF. Best for 0.13 ?m. Possibly applicable for 0.1 ?m by revising production engineering.

157-nm F2. OK for 0.1 ?m and possibly to 0.08 ?m. No good for 0.07 ?m, so can be applicable for only one generation.

146-nm Kr2. No good for 0.07 ?m as is, but may be usable with more research.

134-nm ArKr. OK to 0.07 ?m.

121-nm Ar2. OK to 0.07 ?m, but not practical because laser is not available.

13-nm EUV. OK and only possible candidate for 0.05 ?m.

No conclusion has been made about which will be used during the era between ArF and EUV.

The ASET group conducted a significant and successful 193-nm lithography research effort, fruits of which were transferred to the industry-funded Selete 300-mm evaluation and development consortium. Selete has now begun a three-year project to bring 193-nm (which uses an ArF excimer laser light source) into practical volume production. Work includes efforts in maskmaking, and development of e-beam direct write lithography. In the third year, the group plans to study mix-and-match use of 193 nm and e-beam. Selete is scheduled to receive the first Nikon 193-nm scanning stepper in November.

- P.N.D.