Liquid-metal-jet X-ray technology for nanoelectronics characterization and metrology

Abstract

Front end X-ray metrology applications based on diffraction, scattering or fluorescence such as HRXRD, XRR, CD-SAXS or μXRF rely heavily on the x-ray source brightness for metrology throughput and accuracy. Similarly, high end X-ray imaging applications such as X-ray microscopy (XRM) normally applied in the back end of line also share the same fundamental limitation from the x-ray source. Traditional x-ray sources use static or rotating solid anodes and are therefore typically limited in brightness by when the e-beam power density melts the anode. The invention of the liquid-metal-jet technology has recently overcome this limitation by using an anode that is already in the molten state. The unprecedented brightness achievable by MetalJet sources, which is in the range of one order of magnitude above current state-of-the art solid sources, enable these sources to be readily introduced into high-end metrology applications. This communication will review the status of the metal-jet x-ray source technology specifically in terms of stability, lifetime, flux and brightness relating to specific SEMI metrology applications. It will also discuss details of the liquid-metal-jet technology with a focus on scalability and future improvements.