Particle contamination control technology in electron beam mask writing system for next-generation mask fabrication

Electron beam mask writing is one of the most promising technologies for reliable fine mask patterning in present and future optical lithography. To establish a high performance mask writing system, not only the development of breakthrough technologies for improvement in mask accuracy of CD and image placement of the mask pattern but also the development of contamination control technologies should be pursued. To meet these requirements, the mask blanks upper surface scatter meter for EB writer (MUSE) system has been newly developed. MUSE can evaluate and measure the particles on the mask in vacuum environments and can be attached to the EB system. By using MUSE, not only the investigation of the origin of dust production in the EB system but also productive control of the EB system can be accomplished. This paper describes the MUSE system and the results of particle measurement in the EB mask writing system. The performance of the EB system with respect to particles is presented and discussed.