Development of the Vacuum Spark as an EUV Source for Next Generation Lithography

Abstract

Extreme ultraviolet lithography (EUVL) which requires a radiation in a 2% wavelength band around 13.5 nm is expected to be the next generation lithography (NGL) system. A 13.5 nm EUV source is needed to satisfy the demand for the production of semiconductor chips with critical dimensions of 50 nm and below. Nowadays, plasma based EUV sources such as laser produced plasmas and gas discharges are considered internationally by many as the practical light sources. Recently, much progress has been made in vacuum spark discharges as they seem to offer an alternative with much higher conversion efficiency into EUV photons. The vacuum spark (UMVS-III) being a compact pulsed plasma discharge has been investigated in this laboratory as a possible EUV source. An extension of the earlier research work on X-ray production by the vacuum spark to the EUV region is carried out.