SITE-SPECIFIC ANALYSIS OF ADVANCED PACKAGING ENABLED BY FOCUSED ION BEAMS (FIB)
Authors: Richard J. Young, Chad Rue, Michael Schmidt, Ruud Schampers and David Wall Company: FEI Company Date Published: 10/11/2010
IWLPC (Wafer-Level Packaging)
Abstract: The focused ion beam (FIB) has become an invaluable tool in many aspects of semiconductor process development, circuit edit, low yield analysis, and failure analysis. Its key attributes are the ability to create highly site-specific crosssections and transmission electron microscope samples, and to perform circuit re-wire and debug. Newer packaging technologies, such as, through-silicon-via, redistribution layer fan-in and fan-out, wafer-to-wafer and multi-chip stacks, also require site-specific sectioning as part of process development, testing and failure analysis. These samples require much larger volumes of material to be removed than in the case with traditional FIB applications (e.g. milled volumes in the order of 100 x 100 x 100 = 106 µm3 and larger, rather than say 30 x 30 x 10 ~ 104 µm3), so they are generally seen as being prohibitively time consuming for the FIB. New FIB capabilities are overcoming these limitations and enabling the benefits of localized FIB sectioning to be applied to advanced packaging. These improvements include both the use of larger ion beam currents and the use of highly-enhanced gas-assisted etching.
Key words: Packaging, cross-section, site specific, focused ion beam, FIB