IFTLE 134 SEMI 3D European Summit – Is the Wide IO Driver Dead ?
SEMI European 3D Summit
SEMI Europe held their first European 3D TSV Summit in Grenoble in late January with a
theme of “On the Road towards TSV Manufacturing”. Yann Guillou of Semi reports 320 attendees from 20 countries, 4 keynotes speakers, 22 invited speakers and 22 exhibitors were in attendance.
ST Micro
ST Micro presented their strategy for bringing 3D to manufacturing. An interesting slide compared yields with and without TSV.

They discussed digital / analog partitioning and memory on application processors as driving applications.
ST Ericsson
Kimmich of ST Ericsson discussed the application of 3D integration to smartphones. They were hyping fully depleated SOI technology (FD SOI) as being a faster, cooler and simpler solution.

He reported successful results from their WIOMING 3D application processor [ see IFTLE 86, “ 3D Headlines at the RTI 3D ASIP part Deux” and IFTLE 130 “3D-ASIP part 3,Wioming⦔]
A cross section of the device is shown above ( STM wide IO memory on applications processor). The goal is to offer the same bandwidth as a quad channel 32 bit LPDDR2 interface but with half the power consumption. These are 10um dia TSV on 40 um pitch with AR = 8. The Cu pillar connections are 20um dia on 40 um pitch . ST Ericsson reports there are still business issues concerning the wide IO business model.
An interesting chart on Memory Options shows wide IO bandwidth capability the same as LPDDR3 although the DDR memory takes a significant hit in power efficiency.

Another interesting conclusion is that PoP memory solutions offer better thermal performance since the thinned Si die in the 3D configuration result in poor lateral heat distribution.

In fact, Kimmich concludes that although 3D TSV technology appears ready for mass production, wide IO technology is not yet a fit for mainstream smartphones. LPDDR3 and LPDDR4 will be used in this application due to better thermal performance and lower cost.
GolbalFoundries
Greenwood of GF reitereated their recent theme of global collaboration enabling the global supply chain. Of interest was his slide outlining the production at various GF sites.

When it comes to 2.5/3D, GF is certainly well engaged across the world. The Fraunhoffer ASSID being on the same campus as Fab 1 Dresden is strategically aligned to GF collaboration. This co location insures “â¦an intensive and frequent knowledge exchange at the engineering level”.
AS IFTLE has reported previously see IFTLE 125, “2012 GaTech Interposer Conference, part I”, Fab 8 in NY is responsible for 3D solutions and Fab 7 in Singapore is responsible for 2.5D solutions.
Several 2.5D test structures were shown that were collaborations with Amkor.


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