M. Kawano et al., CONTINUOUS WRITING METHOD FOR HIGH-SPEED ELECTRON-BEAM DIRECT WRITINGSYSTEM HL-800D, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 11(6), 1993, pp. 2323-2326
Hitachi has developed a new e-beam direct writing system named HL-800D
[Y. Sakitani, H. Yoda, Y. Shibata, T. Yamazaki, and K. Ohbitu, J. Vac
. Sci. Technol. B 10, 2759 (1992)]. This system has been developed for
mass production of ultra-large scale integrated circuits such as a 25
6M-DRAM manufactured with high accuracy and high throughput. To achiev
e a productive level of throughput, this system employs a continuous w
riting method with variable stage speed. In the method, an e-beam trac
es a moving wafer stage accurately using deflections during continuous
writing, and the wafer stage moves with the most suitable speed depen
ding on the writing pattern density. The continuous writing method mak
es considerable improvement in throughput compared with a conventional
''step and repeat'' stage moving method. Stitching accuracy is confir
med by test writing.