Vacuum spark discharge soft x-ray source

The vacuum spark X-ray source is a device operating at high frequency, of the order of several kilohertz, where the X- rays are emitted in small dose in each pulse. At ALFT, we are developing such X-ray sources for lithography in a series of models called VSX. Continuous operation at 10 kHz, full voltage (14~15 kV) for more than 9 hours has been routinely obtained with a carefully designed trigger and a movable anode. The X-ray output is 275 (mu) J/pulse at the source with a capacitance of 13 nF. An extendibility study has been carried out focused mainly on debris management and heat dissipation. The study evaluated the possibility of extending the machine to the 150 W X-ray output level required by the semiconductor industry within the operating regime of 40 kHz and anode moving at speed up to 11.2 m/sec.