PROTOTYPE-TEST This Cascade Microtech semiconductor test system is shown undergoing shop tests at Cascade’s offices. Cascade prefers to build and test prototypes and avoids customer site tests. (Source: Cascade Microtech)

“We generally build prototypes,” says Brad Froemke, mechanical engineer with Cascade Microtech in Beaverton, Ore. Cascade builds probes and probing systems for the semiconductor industry. These machines measure electrical parameters in extremely small increments down to attoamps—10-18 amps—and at very high frequencies up to hundreds of gigahertz. Verifying these types of measurements through simulation is virtually impossible.

Electrical parameters and features such as grounding methods, EMI/RFI, PWM rise times and current leakage are primary factors in vendor evaluations. “We have found that the only effective way to evaluate these parameters is to install vendor components in a prototype and test,” adds Froemke. Cascade also uses test equipment from vendors such as Agilent, Keithley, NASA and JPL that are NIST-traceable to make electrical measurements. “We also keep a couple of Ph.D. physicists and EE types in a cage for some of the more esoteric measurements,” chuckles Froemke. “In many applications our machines are used to verify other machines’ measurements.”

Read June's cover story Will The Machine Work? to find the best test methods for proving your machine operation.