Electron beam drift correction method for semiconductor microlithography, by periodically correcting drift, and correcting whenever value of interference factor exceeds predetermined level

摘要

The method involves periodically correcting the drift of the electron beam once per time period while varying the length of the time period. In addition to the correction per time period, the drift of the electron beam is corrected irrespective of the elapsed time period, whenever a change occurs in the value of an interference factor that is greater or equal to a predetermined level. The interference factor may be a value of the external air pressure, temperature, magnetic field, vibration, coolant flow rate or power supply voltage. Independent claims are included for methods of writing on a workpiece using electron beams.