Heterodyne electrostatic force microscopy used as a new non-contact test technique for integrated circuits

In this paper a new high-resolution non-contact scanned probe voltage measurement technique for integrated circuits is presented. Voltages are extracted by sensing the localized electrostatic force between an energized probe and a point on the circuit being tested. Using a nulling method, the technique is capable of accurate magnitude measurements of high frequency signals without complex calibration requirements. An instrument based on the developed technique has been constructed and RF vector waveform measurement of a GaAs MMIC at 1 GHz as well as arbitrary waveform sampling of a CMOS circuit is demonstrated.