November 2011 Nanotechnology Supplement Cover Picture and Story
Cover Story
3D integration is an important new development in semiconductor enabling devices to be more efficiently stacked together to improve performance and reduce power consumption. The ability to physically characterize the through-silicon vias (TSVs) and mechanical bonds used in 3D integration is essential for developing robust manufacturing processes and fabricating reliable products. Focused ion beam (FIB)
systems have long provided physical analysis in the manufacture of integrated circuits, but conventional FIB cannot remove material fast enough to analyze these relatively large structures used in 3D integration.
The launch of a new plasma-based FIB system (VionTM PFIB from FEI Company) now provides the speed and precision needed to develop and deploy these exciting new technologies. The 3D integrated reliability test chip shown on the cover is a 3-level-stack with a modular layout (courtesy Fraunhofer EMFT, Munich). It is designed to permit evaluation of assembly processes between two initial layers and, subsequently, the
effects of adding a third layer. The PFIB can mill a cross section through the entire three layer stack showing critical details of both upper and lower bonding regions and the complete TSV through the middle layer (upper left image).
The three detailed images show (clockwise): chip-chip bonding (using Cu-Sn solid-liquid-interdiffusion bonding process); top of tungsten TSV; bottom of TSV. The sectioning and imaging was all accomplished within the same PFIB system, showing the benefits of fast, precise sectioning followed by high-resolution ion imaging to display details of the interconnections.
For further information contact:
FEI Company
Tel: +1 503 726 7500
Email: info@fei.com
Web: www.fei.com
