Foundry and Assembly Partnerships Move the Industry Forward in TSV Technology

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Foundry and Assembly Partnerships Move the Industry Forward in TSV Technology

By E. Jan Vardaman, TechSearch International, Inc.

Performance requirements such as increased bandwidth, reduced latency, and lower power are driving the adoption of 3D ICs designed with through silicon vias (TSVs). The relationships between the foundry and the semiconductor assembly and test (OSAT) service providers are becoming increasingly critical as the industry moves toward 3D integration. While the business model for 3D TSV assembly is still evolving, process responsibilities as well as the metrics and success criteria for selection of the optimum process flow and cost structure are critical to successful technology adoption. Moving forward will require greater cooperation between foundry and OSAT and will expedite virtual integration of the supply chain.

An interim solution to full 3D integration is the use of a silicon interposer. Some companies call this a 2.5D approach that may be commercialized prior to the industry moving to full 3D adoption. The concept of a silicon interposer is not an entirely new idea, but commercialization today requires key strategic partnerships. Today, research activities for silicon interposers or prototype development are taking place at a number of companies including ALLVIA, Amkor, ASE, Dai Nippon Printing, Ibiden, IBM, IPDIA (formerly NXP), NEPES, Shinko Electric, Silex Microsystems, STATS ChipPAC, and TSMC.

Xilinx Test Part




Source: Xilinx, Inc. 

While many companies have contemplated the design of structures with silicon interposers, the industry infrastructure and supply base for the widespread adoption of the technology has been a concern. The recent announcement from Xilinx in partnership with TSMC and Amkor is an example of the cooperation that is moving the industry forward. Xilinx has announced the development of FPGA slices fabricated by TSMC that sit in a side-by-side configuration and are connected with micro bumps to a passive silicon interposer. The interposer, fabricated by TSMC, uses 65 nm generation silicon technology and has four conventional metal layers to connect each FPGA slice. The silicon interposer with through silicon via is mounted with flip chip interconnect on a conventional flip chip organic substrate supplied by Ibiden. The structure offers a 2X density improvement and provides a lower latency, and a high yield solution.

Engineering samples are planned for mid-2011 and devices will be fabricated on 28nm node silicon technology. This technology development benefited from collaboration with leading industry organizations including IMEC, SEMATECH, and SEMI, as well as equipment manufacturers, fabs, and OSATs. A robust supply chain enabled by close partnerships — among Xilinx for FPGA, interposer and package design plus final package test, TSMC for 28nm FPGA and interposer fabrication, Amkor for micro bumping, die singulation, chip-on-chip attach, and assembly, and Ibiden for package substrate — clearly shows the importance of virtual integration in moving from R&D projects into commercialization. According to Xilinx, other important factors in commercializing this technology include known good die (KGD) and the promotion of standards.

This year, SEMICON Japan (December 1-3 in Chiba) will provide an excellent opportunity to learn some of the new developments from equipment, material, and test suppliers that will enable the commercialization of new technologies such as TSV and silicon interposers. SEMICON provides a unique venue for discussions and a place to set standards that will enable closer partnering between foundry and assembly players.

For more information on SEMICON Japan 2010, please visit

TechSearch International, Inc. was founded in Austin, Texas, in 1987 by E. Jan Vardaman as a technology licensing and consulting firm specializing in the electronics industry. Today it is recognized around the world as a leading consulting company in the field of advanced semiconductor packaging technology. Its goal is to enable clients to compete more effectively by providing accurate, relevant, and timely information on technology trends and market developments. E. Jan Vardaman can be reached at

November 2, 2010