Wafer probing system

11/01/1996

Wafer probing systems

The Summit line of probe stations consists of four systems with 0-300?C measurement capability, incorporating an ultralow-noise electrical chuck. These manual and semiautomatic probing systems are well-suited to wafer-level-reliability (WLR) tests and IC lifetime tests. WLR tests, made at high temperatures, allow design engineers to accelerate semiconductor stress factors and trigger common failure mechanisms. Many WLR measurements require temperatures in excess of 250?C. The thermal chuck solves many of the problems that affect existing 300?C systems. Noise is reduced to <50 fA, even at 300?C; chuck capacitance is reduced 25? over existing systems, allowing shorter settling times and reducing the risk of test-equipment oscillation; and the system permits femtoamp-level measurements to be made with the thermal unit on. Most temperature units must be cycled off to make low-leakage measurements. These systems can also be used to detect mobile ionic impurities, to accelerate data-charge-loss-rate at high temperatures, to accelerate electromigration using both high current and high temperatures, and to characterize special high-temperature devices. Cascade Microtech Inc., Beaverton, OR; ph 503/626-8245, fax 503/626-6023.