On the Opportunity of Liquid Metal Rotated Anode for High Brightness X-Ray Source

Abstract

The new generation compact X-ray source for semiconductor metrology requires a brilliance that is higher than existing technology can offer. In this article, we propose a new X-ray source anode where an electron beam is focused on a rotating liquid metal layer. We assume that high brilliance emission can be achieved with power densities in the range of 1–10 MW/mm2 in the focal spot. The liquid tin layer is formed on top of the rotating anode disk electrode which is partially immersed in liquid tin. This scheme has recently been implemented in the plasma-discharge-based 13.5-nm extreme UV source of the EBL-2 beamline system at TNO. The existing technology of liquid tin circulation can provide cooling of up to 10 kW of input power with peak power densities up to 5 MW/mm2. An opportunity to use a liquid metal layer with the thickness of several tens of micrometers on the fast-rotating metal disk is discussed.