The progress and prospects for fabrication of integrated circuits with x ray lithography are reviewed. Present technology of masks, alignment, resist, and x-ray sources is examined and found to be adequate to produce IC's with 1-to 5 μm design rules. The exposure time is under 5 minutes and the result is reproducible resolution and high yield due to the off-contact exposure process. Fabrication of IC's with sub-micron dimensions is more difficult because precision alignment to 0.1 μm is not yet available and there is not a ready source of intense collimated x rays. High-resolution lithography can be accomplished using special mask-wafer contact methods with some sacrifice in yield. Synchrotron radiation shows the greatest promise for volume production of IC's with submicron patterns, but the application must be proved to justify investment in the costly facilities.
John H. McCoy, John H. McCoy,
"X-Ray Lithography For Integrated Circuits - A Review", Proc. SPIE 0100, Developments in Semiconductor Microlithography II, (8 August 1977); doi: 10.1117/12.955368; https://doi.org/10.1117/12.955368