Paper MS-ThA7
Wafer-level Process Sampling, Metrology and Testing for MEMS and Solar Photovoltaic Applications

Thursday, November 12, 2009, 4:00 pm, Room C3

As MEMS (Micro-Electro-Mechanical Systems) devices further proliferate many industrial and consumer products, the need for fast characterization becomes critical to production process support and time-to-answer in failure analysis. For example, a Dual-Beam can be used to characterize the MEMS fabrication processes by cross-sectioning the area of interest using a focused ion beam and imaging the uncovered feature of interest for metrology and process evaluation using a scanning electron beam or via the ion beam itself. The ion-beam can also be used to weld and cross-section fragile suspended features without additional process steps such as resist backfilling. Most MEMS components, however, are very large on the order of 10s-100s microns, which can lead to long sample preparation times. Furthermore, localized gas chemistry injection on the micron-level at the point of beam-sample interaction further enhance milling rate to support wafer-level multi-site sampling for near-production process support. FA work in MEMS packaging and TSV development for MEMS-CMOS integration also have demonstrated benefits from the gas-enhanced FIB de-processing.

In addition to sample preparation throughput, it is possible to use a micromanipulator probe to remove specific components of the device for characterization. This work also demonstrates that A FIB system configured with such an in-situ sample lift-out probe can remove specific components at their attachment points and lifting them out to characterize their etch profile, rather than attempting to ion mill a large area away to enable access. Both gas-enhanced and lift-out approaches can significantly reduce the amount of time required for a cross-section of the device, and improve the quality of data obtained.