ACTIVE VIBRATION CORRECTION IN ELECTRON-BEAM LITHOGRAPHY SYSTEM

In an electron beam (EB) lithography system, beam positional vibration is one of the most influential factors of positioning accuracy degrad ation. We propose a new correction method for improving this accuracy and investigate its effectiveness by applying it to a nanometer EB sys tem. In our method, first, the correction signal is detecting the beam positional vibration as the variation of tile backscattered or the tr ansmitted electron signal and then extracting one period of this signa l. Then, the correction signal is added to that of the beam deflection control. The effectiveness of this correction is evaluated by measuri ng beam positional vibration and stitching accuracy of the delineated pattern between subfields with size of 8 mu m x 8 mu m. As a result, b oth an amplitude of the beam vibration of less than 10 nm and a stitch ing accuracy of less than 8 nm (3 sigma) are achieved, which confirms that the beam vibration has been actively corrected, and the positioni ng accuracy has been improved. The above results indicate that this co rrection method is very valuable for the EB lithography system.