1. The first external publication describing a practical x-ray lithography system was from D.L. Spears and H.I. Smith, Electron. Lett. 8, 102 (1972). They succeeded in fabricating devices using the technique. Inside IBM, experiments using x-ray lithography were performed by R. Feder around 1969 using a Cr target x-ray tube with two kinds of x-ray masks: Be substrate-Au absorber, and Si substrate-Au absorber. The experiments were documented by Feder (while an employee at IBM East Fishkill, N.Y.) in an unpublished IBM internal Memorandum No. TR 22.1065 dated Aug. 28, 1970, in which a relatively comprehensive proposal for x-ray lithography was described.
2. J. R. Maldonado, M. E. Poulsen, T. E. Saunders, F. Vratnyand A. Zacharias, J. Vac. Sci. Technol.16, 1942 (1979).
3. J. M. Warlaumont and J. R. Maldonado, J. Vac. Sci. Technol.19 (1981).
4. R. R. Mclntoshet al, SPIE632, 156 (1986).
5. M. Lepselteret al, Proc. IEEE71, (1983).