Fabrication of nc-Si Electron Emitter Array Integrated with Active-Matrix Driving LSI for Massively Parallel EB Lithography

摘要

Nanoscale lithographic technologies have been intensely studied for next generation semiconductor manufacturing. Up to the present, mask-less/direct write electron-beam (EB) lithography remains as a candidate to address upcoming 16 nm node and beyond. However, it still remains challenged to provide an acceptable throughput in mass production. Massive parallelism is suggested as a potential solution for this roadblock, and many innovative concepts on the multiple EB imaging have been proposed. If any superior progress in this technology demonstrates a commercially available throughput, it can potentially reduce the cost of manufacturing photomasks for the next generation ULSI devices as well. In addition, it could allow us to realize timely response in making diversified photomasks for MEMS devices where high-mix low-volume production is required. From the aspect of these industrial advantages, we are currently working on the development of massively parallel direct write EB system targeting practical throughput comparable with an existing optical stepper. Electron source used in this system is nanocrystalline Si (nc-Si) ballistic surface electron emitter where 1:1 projection of electron beam has been demonstrated to resolve patterns of 30 nm in width in our previous work. Array of microminiaturized nc-Si electron emitters are integrated with an active-matrix driving LSI, and the beamlets simultaneously exposing pixels are switched on and off by changing CMOS-compatible voltage. This paper presents our designed and prototyped structure of nc-Si electron emitter array compatible with the active-matrix driving LSI, and the validation result of its performance will be discussed.