MICROBEAM SYSTEM FOR STUDY OF SINGLE EVENT UPSET OF SEMICONDUCTOR-DEVICES

A high energy heavy ion microbeam system has just been installed on a beam line of the 3 MV tandem electrostatic accelerator mainly for analysis of single event upset (SEU) of LSI memories in spacecraft. This system was designed for precise beam positioning at a desired microscopic area of the microcircuit, to experimentally evaluate of actual SEU sensitive area, and also to allow single ion hits for observing a transient charge pulse from an SEU. For these purposes, a fair amount of target beam current is required for beam positioning at the desired area. The system is equipped with two lens systems: one to control the target beam current in a wide range down to an extremely low current without any change of the beam optics, and the other to focus heavy ion beams within a spot size of 1-mu-m. The final goal is to hit a microscopic target area with a single 15 MeV nickel ion.