Soft X-Ray Microscopy and EUV Lithography: Imaging in the 20-40 nm Regime

Advances in short wavelength optics, covering the range from 1 to 14 nanometers (nm), are providing new results and new opportunities. Zone plate lenses[1] for soft x-ray microscopy[2,3] are now made to high accuracy with demonstrated resolution of 23 nm with proper illumination and stability. These permit important advances in the study of protein specific transport and structure in the life sciences[4], and the study of magnetic materials[5] with elemental sensitivity at the resolution of individual domains.

Major corporations[6] are now preparing the path for the fabrication of future computer chips, in the years 2007 and beyond, using multilayer coated reflective optics, which achieve reflectivities of 70% in the 11-14 nm region[7,8]. These coated optics are to be incorporated in EUV print cameras, known as "steppers". Electronic patterns with features in the range of 40-70 nm have been printed. The first alpha tool stepper recently demonstrated all critical technologies[9] needed for EUV lithography. Pre-production beta tools are targeted for delivery by leading suppliers[10] in 2005, with high volume production tools available for manufacturing in 2007.

New results in these two areas will be discussed in the context of the synergy of science and technology.

[1] E. Anderson et al., J. Vac. Sci. Tech. B, 18, 2970 (2000)

[2] G. Denbeaux, SRI-2000, Berlin.

[3] W. Chao, SPIE 4146, 171 (2000).

[4] C. Larabell, private communication. W. Meyer-Ilse et al., J. Microsc.

201, 395 (2001).

[5] P. Fischer et al., J. Synchr. Rad. 8, 325 (2001).

[6] Members of the EUV Limited Liability Company are Intel, Motorola,

AMD, Micron, Infineon, and IBM.

[7] T. Barbee et al., Appl. Optics 24, 883 (1985).

[8] S. Bajt, private communication (2002)

[9] D. Tichenor et al., SPIE 4343, 19(2001).

[10] ASML, the Netherlands, at the SPIE Microlithography conference, Santa Clara, CA; March 2001.

This work was supported by the DOE, Office of Basic Energy Sciences, DARPA, and the EUV Limited Liability Company.