Automatic electron beam adjustment when producing submicron structures - where scanning marks on substrate provide signals for electronic processing

An electron beam is rapidly and automatically adjusted with high accuracy in a processing plant w.r.t. reference marks provided on an object sensitive to radiation. When the marks are scanned by the beam, signals are emitted measuring the deviation of the object from its desired position. The improvement is that the deviations are measured in five dimensions (x,y,z,Qx, Qy,), and the scale deviations of the beam deflection are also measured in two directions (x,y); and all the measurements are corrected. For measuring the deviations in position, a number of marks is pref. scanned by the beam and subjected to electronic processing, esp. using one mark for adjustment and the second mark to confirm the correct position and provide data w.r.t. the beam focus. The electronic circuit pref. includes one or two low-pass filters; a peak value meter for storing the max. signal value; a converter providing digital signals; and a digital computer. Continuous, automatic compensation for drift etc. is achieved when using an electron beam to produce structures in the sub-micron range, where one structure can be exactly aligned above another, e.g. in microcircuits.