Knights Technology, Inc.

Tsen-Shau Yang

Ger-Chih Chou

Fu-Chieh Hsu

Kuang-Hua Ken Huang

Christopher Yih

A system for testing integrated circuits is disclosed which uses a mechanical microprobe and the integrated circuit's CAD database. The system is integrated with the CAD database in such a manner that after an initial alignment operation between the CAD database and the integrated circuit being tested, the microprobe can be moved automatically to any spot on the circuit by choosing a point in the CAD database and placing a cursor on that spot. The microprobe is then automatically moved to the point so indicated. A contact sensing circuit allows the probe to be driven into the actual circuit to take measurements or inject test signals without fear of damaging the integrated circuit. The system can operate in numerous modes, each of which provide a different way of visualizing the circuit being tested.

CAD driven microprobe integrated circuit tester

A technique for detecting whether electrical contact between a probe tip and a device under test ('DUT') has been established. A contact sensing circuit has a ground that is isolated from the ground of the DUT (and remaining portions of the test equipment) during contact sensing. The contact sensing circuit has elements that operate to apply a characteristic signal to one of the DUT terminals, such as its ground terminal. This causes virtually all the DUT circuit traces to track the applied signal (relative to the contact sensing ground). The contact sensing circuit further includes elements, coupled to the probe, that operate to detect the presence of the characteristic signal (relative to the contact sensing ground) on the probe. Once electrical contact has been established, the characteristic signal output is disconnected from the DUT, the test equipment ground is connected to the contact sensing circuit ground, and the probe output is coupled to the relevant portions of the test equipment circuitry.

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Cupertino, CA, United States of America

Tsen-Shau Yang