Progress report on the spherical pinch and the vacuum spark EUV/X-ray radiation sources

Summary form only given. The field of EUV/X-ray lithography sources is an evolving one in which the technologies competing to complement the multiple beam synchrotrons as radiation sources are mainly plasma based. There are several of these plasma technologies: laser-produced plasmas, dense plasma focus, Z-pinch, X-pinch, vacuum spark, spherical pinch, etc. The radiation wavelength to be used in microlithography can either be in the EUV or soft X-ray regions. In both cases, the plasma sources are well positioned to complement the synchrotron because of their granularity and flexibility to adapt to various work environments. For a number of years now the company Advanced Laser and Fusion Technology, Inc. (ALFT) has chosen two plasma technologies for development as point sources of radiation for microlithography. They are the vacuum spark technology, and the spherical pinch technology. Both have a long history of previous research to support the contention that they are well qualified to be converted into technological tools for the manufacturing of next generation of chips. The vacuum spark is essentially a miniature discharge capable of emitting EUV/soft X-ray radiation. Because the radiation is emitted in small dose in each spark, it is necessary to repeat the phenomenon at high repetition frequency, of the order of several kilohertz, in order to meet the requirements of microlithography. Quite to the contrary, the spherical pinch is a high dose plasma radiation source for each discharge, and the repetition frequency can be contained within one hertz or so.