EBL resist heating error and its correction

The temperature during electron-beam lithography (EBL) rises locally by a few tens or hundreds of degrees, causing change of resist sensitivity and leading to variation of critical dimensions. A method to increase the throughput of writing without causing additional linewidth error is necessary to reduce the cost of a mask. Two methods of correction were examined. In the first method, the exposure doses for individual flashes were adjusted so that the heating error was suppressed. The second correction method took into account the fact that the adjustment of exposure doses for individual flashes corrects for heating; however, it also changes proximity effects. In turn, dose modulation in proximity correction leads to different temperature increases. Both effects were taken into account simultaneously. The exposure doses of flashes were determined to correct for both effects.