Accuracy and resolution of scanning electron microscopy and an electron-beam lithography system directly depend on beam diameter; it should be monitored and tuned frequently. A technique is described to determine beam size using an automatic procedure. In the developed method, a specially designed and fabricated test pattern is scanned using an e-beam. A spectrum of the signal is analyzed; beam diameter is automatically determined using a software program. Results of design, fabrication, and analysis of the beam calibration test pattern are presented. (c) 2006 American Vacuum Society.