LPP source system development for HVM

Laser produced plasma (LPP) systems have been developed as a viable approach for the EUV scanner light source for optical imaging of circuit features at sub-32nm and beyond nodes on the ITRS roadmap. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from leading scanner manufacturers. We present the latest results on power generation, stable and efficient collection, and clean transmission of EUV light through the intermediate focus. We report on measurements taken using a 5sr collector optic on a production system. Power transmitted to intermediate focus (IF) is shown. The lifetime of the collector mirror is a critical parameter in the development of extreme ultraviolet LPP lithography sources. Deposition of target material as well as sputtering of the multilayer coating or implantation of incident particles can reduce the reflectivity of the mirror coating during exposure. Debris mitigation techniques are used to inhibit damage from occuring, the results of these techniques are shown. We also report on the fabrication of 5sr collectors and MLM coating reflectivity, and on Sn droplet generators with droplet size down to 30μm diameter.