| 摘要 |
PURPOSE:To enable to perform a high-speed patterning by a method wherein, using the clock having fixed frequency, the optimum irradiating time for an electron beam is approximated by the integer-fold clocks. CONSTITUTION:In the method wherein an electron beam is formed by a slit and a patterning is performed by increasing or decreasing the beam irradiating time for every shot, first, beam current density is measured, and a reference irradiation time TS is determined. When basic clock frequency t is 5ns, for example, if the reference irradiation time TS is 100ns, the reference irradiation time TS becomes the integral time of the clock frequency t, and as the dividing width 5% of the amount of variation of the irradiation time is coincided with the clock frequency, the irradiation time can be controlled accurately. When the reference irradiation time TS is 111.1ns, for example, which is not an integral multiple of the clock frequency t, the beam irradiation time is controlled by having the reference irradiation time TS and the amount of variation approximated by integrally multiplying the clock frequency t. |
