Beam current measuring device and apparatus using the same

摘要

A beam current measuring device (BMD) capable of measuring beam current while radiating the beam on a target, such as a semiconductor wafer. The BMD at least includes: (a) a detecting section for detecting or collecting a magnetic field corresponding to the beam current; and (b) measuring section including (i) a SQUID sensitive to magnetic flux, and (ii) a feedback coil for carrying feedback current to cancel out a change in the magnetic flux penetrating through the SQUID. With finite beam current except zero penetrating through the detecting section, the SQUID is locked. A BMD of the present invention can be incorporated and used in an ion-implantation apparatus, electron beam exposure apparatus, accelerator, and the like.