Perspectives From the Leading Edge

Many of you will have already seen the press release that Dresden will be the site of a Fraunhofer 3-D silicon research institute. I decided to dig a little deeper, so I contacted colleagues in Berlin and Munich to learn more.

The newest Fraunhofer center, All Silicon System Integration Dresden (ASSID), will report into old friend Herbert Reichl, head of Fraunhofer IZM, which has branches in Berlin and Munich. The focus of the new center will be on prior-to-BEOL (vias middle) TSV, silicon interposers, thin die integration and 3-D stack formation. The center's goals include:

• TSV in passive and active semiconductor wafers.
• Silicon interposer technologies for high-density wiring and the integration of passive components, antennas, optical components and cooling techniques.
• Die-to-wafer and wafer-to-wafer interconnect formation.
• Low-temperature bonding and wafer-level assembly technologies.
• Wafer-thinning technologies for bumped and partially assembled wafers.
• Thin-wafer handling and bond/de-bond technologies.
• Reliability models for 3-D silicon integration.
• Characterization, testing of 3-D systems.

According to M. Juergen Wolf, project manager and program coordinator, Munich will continue process development on its 200 mm line, and Berlin will continue process development on assembly processes and thin wafer handling. Munich will further develop its core competencies in silicon-based 3-D integration on its 200 mm CMOS line — focusing on TSV technology, metal bonding (e.g. SLID) and thin wafer/die handling, including innovative concepts such as electrostatic carriers (e-chucks), according to Peter Ramm of IZM-Munich. Processing developed by the Fraunhofer IZM research groups in Berlin and Munich will be transferred to the 300 mm line in Dresden. When complete, this will become the first complete 300 mm line for prototype fabrication of 3-D integrated devices, Ramm said.

ASSID is intended to function as a competence center for all-silicon system integration throughout Germany and Europe. This includes working together with industry to analyze existing and develop new research roadmaps and strategies. This center is to develop a global perspective, taking future product areas directly into technology development goals.

The research institute is scheduled to launch its activities in December in a Fraunhofer-owned cleanroom facility of memory chipmaker Qimonda. They will use already-installed 300 mm equipment capable of wafer-level back-end processing such as redistribution. Additional new equipment required for a complete 300 mm 3-D integration pilot line, which includes 300 mm TSV etching, filling, thin wafer handling and bonding equipment, will come from the investment of €49 million coming to the center from the German government and the state of Saxony. A second-phase site expansion is possible, which would bring the center to full functional capability over two phases in ~1.5 years.

Semiconductor companies located in Dresden include AMD (now GlobalFoundries), Infineon, ZMD, X Fab and the recently failed Qimonda. Institute partner companies will have the option of using the center at night for prototype manufacturing, thereby being able to directly transfer the gained research results and developments into products.

There is reported interest from GlobalFoundries for the services of ASSID. The GlobalFoundries spinout of AMD intends to offer early access to volume chip production using leading-edge technologies. The foundry has announced that it is proceeding with plans to expand its Dresden manufacturing lines by bringing a second 300 mm manufacturing facility with bulk silicon capabilities online in late 2009. The Dresden cluster will initially be focused on production of high-performance 45 nm silicon-on-insulator (SOI) technology in Module 1. Module 2 will transition to 32 nm bulk silicon capabilities.

Fraunhofer IZM is a partner in the EMC-3D Consortium, a network of nine international companies and research institutes, where it is responsible for process integration. The center will be able to offer these companies collaborative, product-oriented process development capabilities, including prototype fabrication in the 300 mm ASSID 3-D line.

Best of luck to this much needed enterprise. I’m sure we will be talking more about it in the future.

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