Wafer probes operates to 220 GHz
Staff -- Test & Measurement World, 11/1/2006
Cascade Microtech has announced enhancements to its line of Infinity probes, supporting finer pitches (down to 50 microns) and smaller contact areas (with pads as small as 25 x 25 microns) while extending the operating frequency range to 220 GHz.
The probes serve in semiconductor process characterization and can probe mixed-signal MOS devices used in wireless-communication applications. In addition, they can test high-frequency interconnects and devices such as amplifiers, mixers, oscillators, multipliers, and switches used in automotive collision-avoidance systems, satellite telecommunications, radio astronomy, spectroscopy, surveillance, and medical imaging.
The Infinity probe combines the vendor’s proprietary thin-film technology with coaxial technology to optimize return loss, attenuation, and crosstalk specifications. Cascade Microtech reports that the microstrip transmission lines on the Infinity probe’s thin-film tips confine fringing fields more tightly than conventional flexible coplanar tips, and the company adds that the resulting improved field confinement reduces unwanted couplings to nearby devices or other probe tips, thus increasing RF measurement accuracy.
The probes are also designed to optimize precision RF connections to aluminum pads on a wafer—a task that’s more difficult than connection to gold pads. The Infinity probe’s performance on aluminum pads, the company reports, is achieved by optimizing the key probe factors that affect contact resistance: tip contact area, force applied, tip metallurgy, and scrub. The force delivery of the Infinity probe is such that only a small horizontal motion (scrub) is necessary to break through the aluminum oxide to make contact with the pad. This, coupled with the Infinity probe’s non-oxidizing tips, ensures minimal pad damage and superior contact on silicon devices with pads as small as 25x25 microns.
The Infinity probe is available in versions operating to 40, 50, 67, 110, 140, 170, or 220 GHz. Pitch sizes include 50, 75, 100, 125, 150, 200, and 250 microns.
Base price: $895. Cascade Microtech, www.cascademicrotech.com.
