LOW-VOLTAGE BACKSCATTERED ELECTRON COLLECTION FOR PACKAGE SUBSTRATES AND INTEGRATED-CIRCUIT INSPECTION

A low voltage backscattered electron collection technique has been developed. This technique collects low energy backscattered electrons in a sequential retarding field environment. This collection approach provides most of the desirable features for insulating package substrates and passivated integrated circuit (IC) devices inspection. These features are (1) high current and resolution, (2) high detector gain at low voltage, (3) good signal immunity from sample surface charging, and (4) on-line topographical and compositional information at low voltage. In this paper, various details of the technique; such as detector arrangement, signal collection efficiency, sample charging immunity, beam current and resolution, image distortion and its comparison with conventional low voltage scanning electron microscopy inspection for insulating package substrate, and passivated IC inspection will be discussed.