Japan Starts EUV Development Project

Kenji Tsuda, Asia Contributing Editor -- Semiconductor International, 5/22/2008 5:36:00 AM

A new alliance for extreme ultraviolet (EUV) lightsource development has started in Japan after the completion of EUV exposure basic technology development in the Extreme Ultraviolet Lithography System Development Association (EUVA, Kawasaki, Japan), which concluded in March 2008. In May, the consortium held the final conference to report results of EUV lightsource development. Major results showed 60 W EUV power at the intermediate focus point with laser-produced plasma (LPP) and 20 W EUV power at the intermediate focus point with discharge-produced plasma (DPP). The previous project ended in March was supported by the Ministry of Economy, Trade and Industry (METI) in Japan with $125M for five years.

The results of the EUV lightsource, however, are not enough for commercialization, where the source target is set at over 115 W, which corresponds to a throughput of 100 300 mm wph. The new alliance includes Usio Inc. (Tokyo) and Komatsu Ltd. (Tokyo) for EUV lightsource development, and Nikon Corp. (Tokyo) and Canon Inc. (Tokyo) for EUV lithography equipment development, along with a two-year contract to the New Energy and Industrial Technology Development Organization (NEDO), a subsidiary of METI. The contract can help the new alliance use the previous EUVA project facility.

The largest challenge in developing EUV lightsources is to suppress debris, dust or contamination from the sputtered wall by the plasma atmosphere. Without debris suppression, the lightsource may rapidly deteriorate. Preventing the contamination of mirrors and photomasks is essential for normal operation of the EUV source.

In an application to NEDO, the EUVA proposed a new proposal regarding the cleaning technology of EUV sources, which includes contamination evaluation techniques of masks and mirrors of a EUV source to be used in the 32 nm half-pitch era and cleaning techniques for a focused beam system. The new proposal is expected to be accepted by late May. The EUVA expects the new contract may start this year for a span of three years.

Nikon, Canon and ASML (Veldhoven, Netherlands) now also provide alpha machines to R&D centers, but their EUV power is still so small that they cannot be applied for mass production of <32 nm chip manufacturing. More powerful EUV lightsource development is emerging.