GEORGETOWN, Massachusetts, July 12, 2011 /PRNewswire/ --
- FD-SOI Determined to Be More Economical ThanPlanarBulk Silicon CMOS Processing
Research firm IC Knowledge LLC has completed a comprehensive
cost analysis that determines fully depleted silicon-on-insulator
(FD-SOI) wafers offer the global semiconductor industry the most
cost effective solution compared to bulk silicon for processing
semiconductor devices at the next-generation 22 nm technology node
"FD-SOI offers the potential for significant process
simplification, making it cost competitive while simultaneously
offering performance improvements over bulk silicon," said Scotten
W. Jones, president of IC Knowledge. "The ability to use fewer
steps enables FD-SOI's greater cost efficiency."
In particular, FD-SOI processing dramatically decreases the
number of implant masks and implant steps needed. Although
implant-related costs are relatively low, FD-SOI's fewer total
processing steps offers a simpler overall process flow.
"Fully depleted SOI is the key," Jones added.
In conducting its analysis, IC Knowledge worked with a
wafer-processing consultant and Soitec, the world leader in SOI
wafer manufacturing, to define three sample process flows
representative of state-of-the-art industry practices for the 22 nm
node: one planar bulk CMOS and two versions of FD-SOI - with
implanted source/drain or with in-situ doped source/drain.
All process flows assumed three threshold voltages, dual gate
oxides and suitability for system-on-a-chip (SOC) applications. The
bulk CMOS process assumed a suite of mobility-enhancing stressors.
The two FD-SOI process flows, on top of relevant mobility-enhancing
stressors, also assumed multiple features such as n+ and p+
back-gates and n-well and p-well implants under the buried oxide
(BOx) layer, access to the n-well and p-well, two shallow-trench
isolation depths and electro-static discharge (ESD) devices in a
bulk area. The same gate integration schemes (gate-last
high-k metal gate) and number of metal layers (eight) were
assumed in all scenarios. For SOI, a volume pricing of $500 per
starting wafer was added. For bulk silicon, an aggressive price of
$130 per (epi) starting wafer was selected.
IC Knowledge then utilized its Strategic Cost Model to evaluate
how each process flow would perform in a Taiwanese wafer fab
producing 30,000 wafers per month in the 2012 timeframe. The
scenario generator considered the costs of starting wafers, direct
and in-direct labor, depreciation of the wafer fab, equipment
maintenance, monitor wafers, facilities such as electricity, and
consumables such as reticle sets, gases and chemicals. Calculations
of the cost per wafer yielded used in the model have been validated
by IC Knowledge using wafer cost data collected from fabs
throughout the semiconductor industry.
The Strategic Cost Model's analysis determined that the most
economical yielded-wafer cost was achieved by FD-SOI processing
with in-situ doped source/drain, at approximately $3,000 per wafer.
Furthermore, both versions of FD-SOI were determined to be
extremely cost competitive compared to bulk CMOS. The study found
only about one percent difference in the cost of yielded processed
wafers produced by the second FD-SOI option - with implanted
source/drain - and bulk CMOS.
Because this analysis is strictly based on costs, IC Knowledge's
findings do not address FD-SOI's superiority to bulk silicon in
producing semiconductors with lower leakage and faster processing
speeds or compare the performance of SOI and bulk silicon in
processing multi-gate transistors at the 22 nm node and beyond.
The report is available on:
IC Knowledge is the world leader in cost modeling for the
semiconductor and MEMS industries. In addition to custom projects
IC Knowledge offers a variety of cost modeling tools as well as
reports, databases and forecasts. IC Knowledge's customers include
leading semiconductor and MEMS companies, OEMs, fabless design
houses, system manufacturers, industry analysts and many others.
For more information please visit http://www.icknowledge.com
Scotten W. Jones
IC Knowledge LLC
Ph: +1(978)352 - 7610
SOURCE IC Knowledge