A high‐speed, high‐precision electron beam lithography system (electron optics)

A variably shaped electron beam exposure system HL‐600 has been developed for both direct wafer writing and mask making. It was designed as a high‐throughput tool to cover lithography requirements down to a 0.5 μm linewidth. To achieve this high‐throughput capability, many newly developed techniques were adopted in the electron optics and in the control electronic circuits. The simplified electron beam column consists of only four magnetic lenses. The magnetic deflection for main field scanning was enlarged so as to reach up to 6.5 mm sq in order to reduce the overhead time associated with work stage movement. In addition, the design of an objective lens system with a small aberration, and an algorithm for deflection aberration correction were developed. Automatic measurement of defocusing and astigmatism aberrations at a number of sample points were performed by taking through focusing, and the third order polynomial correction function of deflection was determined. As a result, the edge resolution for t...