A probe technology for 110+ ghz integrated circuits with aluminum pads

There is a growing interest in probing Sibased RFICs and test structures with aluminum pads. Probing RFICs with aluminum pads is significantly more difficult than probing ICs with gold pads. This is because a thin layer of aluminum oxide (about 60 angstroms thick) naturally forms on the aluminum surface that impairs the electrical contact between the tips of the probes and the aluminum pads. Any measurement that is sensitive to a series resistance will be affected by contact resistance variations. Such measurements include inductor Q measurements and long characterization tests that require repeatable device contact for time periods beyond a few minutes.