ABSTRACT
On-wafer test of radio frequency (RF) devices is almost an ideal measurement environment. Test interface technologies exist to support vector or scalar measurements. RF on-wafer testing was used only for the s-parameter test, for two port devices up to 18 GHz. Until 1985 the standard approach to characterize at microwave frequencies and qualify a semiconductor wafer before shipping was to dice it up, select a few devices, typically one in each quadrant, assemble them, and then test them in a fixture, recording s-parameters or power levels. Any system requiring full parametric measurement necessitates a complex RF matrix scheme to integrate all capabilities into a single function platform. Traditional RF probes convert a coax transmission line into coplanar signal and ground probe points. Wafer level RF testing using coplanar probing techniques can easily be accomplished provided the constraints of the RF probe design are incorporated into the circuit layout.
