SYNCHROTRON-RADIATION LITHOGRAPHY FOR MANUFACTURING INTEGRATED-CIRCUITS BEYOND 100 NM

Extreme ultraviolet lithography is a powerful tool for printing featur es of 0.1 mu m and below; in Japan and the USA there is a growing tend ency to view it as the wave of the future. With Schwarzschild optics, replication of a 0.05 mu m pattern has been demonstrated in a 25 mu m square area. With a two-aspherical-mirror system, a 0.15 mu m pattern has been replicated in a ring slit area of 20 mm x 0.4 mm; a combinati on of this system with illumination optics and synchronized mask and w afer stages has enabled the replication of a 0.15 mu m pattern in an a rea of 10 mm x 12.5 mm. Furthermore, in the USA, the Sandia National L aboratory has succeeded in fabricating a fully operational NMOS transi stor with a gate length of 0.1 mu m. The most challenging problem is t he fabrication of mirrors with the required figure error of 0.28 nm. H owever, owing to advances in measurement technology, mirrors can now b e made to a precision that almost satisfies this requirement. Therefor e, it is time to move into a rapid development phase in order to obtai n a system ready for practical use by the year 2004. In this paper the status of individual technologies is discussed in light of this situa tion, and future requirements for developing a practical system are co nsidered.