• Article
Published in January/February 2008 issue of Chip Design Magazine
EDA Is Stepping Up to Meet New DFM Demands
"Smaller, faster, and cheaper” has been the mantra of the
semiconductor industry for over 40 years. But the latest
45- and 32-nm technology nodes have many in the semiconductor
industry crying “uncle.” Efforts to deliver technology on the timeline
demanded by Moore’s Law have collided head-on with the economic
realities of semiconductor manufacturing. It’s just too costly. Students
of “techonomics” (the interdependency of technology and economics)
have one heck of a case study on their hands.
By 2011, semiconductor content in electronic products is predicted
to reach its highest peak ever at 24.5% (IC Insights). Fueling this
growth is the complexity associated with the burgeoning consumerelectronics
market including 3G, 4G, Wi-Fi, Auto, Flash, and Hi-
Def. To meet consumers’ insatiable demands, capital spending is
expected to grow from over $50 billion in 2006 to over $80 billion
in 2011 (IC Insights). At the same time, the semiconductorindustry
business environment is changing dramatically. Many
integrated-device manufacturers have adopted a “fab lite” model.
Or they’re getting out of leading-edge development altogether and
relying on foundries instead.
Electronic design automation (EDA) can only grow stronger
as a result. Although it was traditionally all about automation
and simulation, EDA is now being called upon to enable the
integration, sharing, and analysis of complex information from
design to manufacturing. In fact, changes within the semiconductor
manufacturing sector are providing the biggest opportunity for the
EDA industry since its inception in the early 1980s.
Initially, EDA companies provided an automated means to lay out
and connect the components of an integrated circuit. It sounds
simple today, but it was revolutionary for that time. The industry
subsequently grew to handle timing closure, power, verification,
and signal integrity. Still, EDA remained somewhat disconnected
from the ultimate manufacturing process.
Over the past several years, this disconnect became untenable. With the growing complexity of chips, narrowing market windows, and increasing expectations to meet required return on investment (ROI) with the first lot off the line, the industry demanded another look at how far down the flow design should reach. Design for manufacturability or “DFM” was coined to describe a wide range of processes—most importantly, the ability to place manufacturingrelevant information into design tools to improve accuracy, decrease TAT, and improve yield.
Doing DFM correctly requires expertise in both design and
manufacturing. Tools and flows must ensure that the right
information is provided in the right place at the right time. A portal
or common platform must be provided to carry the information from
manufacturing up into design. For example, a DRC-clean design
could result in lithographic hot spots for a given process that—worst
case—will reduce yield. If such hot spots were discovered earlier, you
could make corrections to the design automatically and save a great
deal of time. While much of DFM’s focus is currently on lithography
simulation, consideration must be given to chemical mechanical
polishing (CMP), stress, and etch. Eventually, cost, complexity, and
TAT issues will dictate that all key unit processes be simulated.
Ultimately, the value of DFM to the customer lies in providing a
predictive environment. Such an environment would allow designers to
accommodate the constraints and variability of a manufacturing process
in order to optimize performance, power, yield, and cost. The result
would be greater assurance that the costly semiconductor manufacturing
facilities would remain as efficient and productive as possible.
Where does this leave DFM’s future? By building on what we’re
developing today, a virtual manufacturing environment can be created.
Such an environment would allow designers to run potential designs
through a virtual process, automatically optimizing the design before
it is ever committed to the expensive silicon manufacturing process.
The elimination of even one silicon run or the gain of just one yield
percentage point can have enormous impact on the value chain.
Techonomics will demand such an environment.
Building this environment isn’t a trivial task. Close relationships must be formed with equipment manufacturers. In addition, integrated flows must be created and fab data has to be correlated. Physics-based models also must be generated. What EDA companies have always done very well is tackle complex problems and provide software to automate the necessary tasks for an accurate, timely result. For over 20 years, EDA has been training to address the challenges that we’re finally facing today. We are up to the task.
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