Electron beam scanning method for mark detection

Abstract

Abstract PURPOSE:To make positioning using constant generation of secondary electrons caused by scanning by a method wherein beam length is made constant in the direction of beam scanning and charged in the direction of mark edge depending on the speed of scanning. CONSTITUTION:If the speed of scanning is increased in mark scanning area to facilitate resist removal, then secondary electron generation per unit time is reduced to cause mark detection to become impossible. If beam size is expanded to increase the amount of secondary electron generation, the difference between electrons from the mark and those from other area becomes small to cause detection to be difficult. Thus, the beam size BM1 in the direction of mark scanning is made constant, and the size BM2 at right angle is increased. This allows constant secondary electron generation if marking speed is increased. Because the beam size is not changed in the direction of mark scanning, mark detection accuracy is kept constant. In this manner, mark detection can be performed without causing detection accuracy decrease and resist removal difficulty.

Inventors

• 👤 Junichi Kai
• 👤 Nobuyuki Yasutake
• 👤 Toru Funayama

Bibliographic Details