SAN JOSE, Calif. -- Elpida Memory Inc., Powertech Technology Inc. and United
Microelectronics Corp. (UMC) have formed an alliance to speed up the development
of three-dimensional (3-D) chips at the 28-nm node as well as other processes.
The 3-D devices will be based on through-silicon-vias (TSVs). This
collaboration will leverage the strengths of Elpida's DRAM technology,
Powertech's assembly, and UMC's foundry logic technologies to develop 3-D
devices. This includes devices that integrate logic and DRAM.
It's unclear which company will actually make the 3-D devices. The companies
also did not announce a timetable.
A plethora of companies, including ASE, Elpida, IBM, Intel, Samsung, Toshiba,
TSMC and others, are exploring the possibly of stacking current devices in a 3-D
Experts define a true 3-D package as one that stacks various chips vertically
and then connects them by deploying TSVs. The aim is to shorten the
interconnections between the chips, reduce die sizes and boost device
So far, chip makers are shipping limited 3-D devices based on TSVs, mainly
CMOS image sensors, MEMS, and, to some degree, power amplifiers. Elpida claims
to have devised a DRAM based on TSVs.
There are several problems with TSV technology: Lack of EDA design tools;
complexity of designs; integration of assembly and test; cost; and lack of
But close integration of DRAM and logic technologies using TSV technology are
expected to deliver the performance for a new class of chips. The
UMC/Powertech/Elpida collaboration will facilitate the development of a total
solution that includes logic/DRAM interface design, TSV formation, wafer
thinning, testing and chip stacking assembly for customers.
"Last year Elpida was the first to successfully develop an 8-gigabit DRAM
based on TSV technology," said Takao Adachi, director and chief technology
officer of Japan's Elpida Memory, in a statement.
"The big advantage of this technology is that it enables a large number of
I/O connections between logic and DRAM devices. This can massively increase the
data transfer rate and reduce power consumption, making possible completely new
kinds of high-performance devices,'' he said.
''However, we need a solid partnership with a logic foundry to make this
happen. The joint development that we now plan with UMC means that we can use
the most advanced TSV integration technology to bring together our advanced DRAM
technology and UMC's leading-edge logic foundry technology including experience
in providing SoC solutions such as advanced microprocessors,'' he said. ''Our
plan now is to speed up development in a way that supports ultimate system
solutions that will be made possible by freely joining together all kinds of
devices through TSV integration."