Electron beam pattern transfer system having an autofocusing mechanism

摘要

An electron beam pattern transfer system is disclosed which includes a photoelectric transducing mask disposed within a vacuum container and adapted to transfer a photoelectron beam pattern corresponding to a pattern of the mask onto a sample according to an amount of an incident light, a DC voltage generator connected to vary a voltage applied between the mask and the sample, and a focusing coil of a superconductive magnet for creating a magnetic field of a predetermined intensity between the mask and the sample. When a mask-to-sample distance and/or magnetic field intensity varies undesirably, the variation is electrically detected by detectors. In order to compensate for the defocusing of the photoelectron beam pattern on the sample due to the above-mentioned variation, a microprocessor automatically calculates an amount of correction with respect to the intensity of the electric field between the mask and the sample, on a real-time basis and supplies its control signal to the DC voltage generator.