High-resolution X-ray

MASER Engineering is pleased to announce that the paper on "High-resolution X-ray computed tomography of through silicon vias for RF MEMS integrated passive device applications" has been published as Microelectronics Reliability paper online. This paper has also been submitted submitted to ESREF 2015.

High-resolution X-ray computed tomography of through silicon vias for RF MEMS

P.J. de Veen @, C. Bos @, D.R. Hoogstede @, C.Th.A. Revenberg @, J. Liljeholm ẞ, T. Ebefors ẞ

@ MASER Engineering B.V., Capitool 56, 7521 PL Enschede, The Netherlands
ẞ Silex Microsystems AB, Bruttovägen 1, SE-175 26 Järfälla, Stockholm, Sweden

Abstract
This paper presents our exploration of microfocus and high-resolution X-ray computed tomography (CT) on open high-aspect ratio through Silicon via (TSV) test structures, the interior wall covered with a ~10 μmthick conformal Cu plating, using state-of-the-art and commercially available X-ray systems. Goal of our research is to better understand the physical failure mechanisms of defective open TSVs, in order to further improve the yield of TSV production for integrated passive devices (IPD) to be used in radio frequency microelectromechanical system (RF MEMS) applications.
Micrometer-sized defects were non-destructively identified in some of the open TSVs (i.e. Cu plating thickness deviations, incomplete plating and large voids) using microfocus X-ray CT, which were then verified by destructive mechanical cross-sectioning.With high-resolution X-ray CT, which has almost an order ofmagnitude better resolution, (sub) micron-sized defects in TSVs were directly non-destructively identified and localized, without the need for further destructive inspection techniques for confirmation. The Cu plating thickness variations, in TSVs all connected to a large-area redistribution layer, were found to be design related; based on these failure analysis findings, a new electroplating procedure has been established.

Keywords
Through silicon vias, RF MEMS, Integrated passive devices, Reliability, Failure analysis, Non-destructive physical analysis, X-ray microscopy, High-resolution X-ray computed tomography.

For more information on this paper, please contact Mr. Kees Revenberg or Mr. Wilhelm Niessen.