DESIGN OF HIGH-VACUUM TEST STATION FOR RAPID EVALUATION OF VACUUM MICROELECTRONIC DEVICES

To facilitate rapid testing of several individual or different vacuum microelectronic devices during one pump-down, a high-vacuum test station has been designed and built. The system consists of a turbo-pumped vacuum chamber reaching a base pressure, at room temperature, of 3 x 10(-9) torr. Devices which are fabricated on silicon or fused silica substrates are placed on a copper base which is part of a cold finger cryostat. Test temperatures can be varied from 20 to 500 K. Access to the electrode pads is accomplished by four tungsten probes which are connected to high-vacuum XYZ manipulators. Devices positioned within a 6-cm2 area can be reached by each of the probes. Probe placement is monitored through a zoom microscope/video camera system with a magnification on the video screen ranging from 50 to 400 x. Baking of the devices can be accomplished by thin-film heating elements integrated onto the substrates or by heating coils placed inside the chamber. Cleaning of electrode surfaces can be performed via an argon ion gun system and/or by electron bombardment. Performance of the system will be demonstrated for a Spindt emitter array.