Development of massively parallel electron beam direct write lithography using active-matrix nanocrystalline-silicon electron emitter arrays

Nanoscale lithographic technologies have been intensively studied for the development of the next generation of semiconductor manufacturing practices. While mask-less/direct-write electron beam (EB) lithography methods serve as a candidate for the upcoming 10-nm node approaches and beyond, it remains difficult to achieve an appropriate level of throughput. Several innovative features of the multiple EB system that involve the use of a thermionic source have been proposed. However, a blanking array mechanism is required for the individual control of multiple beamlets whereby each beamlet is deflected onto a blanking object or passed through an array. This paper reviews the recent developments of our application studies on the development of a high-speed massively parallel electron beam direct write (MPEBDW) lithography. The emitter array used in our study includes nanocrystalline-Si (nc-Si) ballistic electron emitters. Electrons are drifted via multiple tunnelling cascade transport and are emitted as hot electrons. The transport mechanism allows one to quickly turn electron beamlets on or off. The emitter array is a micro-electro-mechanical system (MEMS) that is hetero-integrated with a separately fabricated active-matrix-driving complementary metal-oxide semiconductor (CMOS) large-scale integration (LSI) system that controls each emitter individually. The basic function of the LSI was confirmed to receive external writing bitmap data and generate driving signals for turning beamlets on or off. Each emitted beamlet (10 × 10 μm² ) is converged to 10 × 10 nm² on a target via the reduction electron optic system under development. This paper presents an overview of the system and characteristic evaluations of the nc-Si emitter array. We examine beamlets and their electron emission characteristics via a 1:1 exposure test.