System and method for testing and fault isolation of high density

Abstract

Apparatus and method are disclosed for performing testing and fault isolation of high density passive boards and substrates. Using a small number of moving probes, simultaneous network resistance and network capacitance measurements may be performed. Thus, test time is minimized by eliminating the need for electrical switching and/or excessive probe movement during the test of a normal circuit board network. Simultaneous network capacitance and network leakage measurement are also achieved using phase-sensitive detection. Dual-frequency measurement techniques allow the measurement of both the capacitance value and resistance value of a leakage path between a network being measured and an unknown network. Any leakage resistance between a network under test and ground or power planes within the circuit board may also be determined from the measurements. Simultaneous independent net-to-plane capacitance characterization is also achieved using signals of mutually independent frequencies accompanied by minimal signal processing. Thus, improved defect detection capabilities are obtained.