Fast, reliable mechanical probing of submicron features a new tool that combines gas-assisted FIB and mechanical probing

Progress in electron-beam prober technology [1] has not eliminated the need for mechanical probing of ICs. Analog circuits, recent advancement of mixed signal and low voltage digital designs all often require high accuracy, low noise signal acquisition. While not providing the capabilities of an e-beam, mechanical probes offer some significant advantages over non-contact measurement techniques: DC accuracy, small signal AC accuracy, single-shot measurements, low noise and high voltage (V>+/-10V) as well as the ability to inject a known signal into a specific circuit element. Mechanical probes have, however, been plagued by several drawbacks. These difficulties are primarily associated with the limitations of optical microscopy - relatively low magnification (compared to charged particle Seam microscopes), poor spatial resolution and, above all else, small depth-of-focus. This paper describes a new tool which combines the capabilities of FIB, as a large depth-of-focus, high resolution microscope, and a piezoelectric stage technology for sub-micron mechanical probe positioning in the vacuum chamber (MPC). Several novel applications are presented.