thermal control of electronics: perspectives and...
TRANSCRIPT
Thermal Control of Electronics: Perspectives and Prospects
Dr. Robert Hannemann
Rohsenow Symposium on Future Trends in Heat Transfer
Massachusetts Institute of Technology16 May 2003
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Introduction
Thermal control of electronics is posing significant challenges (again)
New, or re-invented technologies will be needed
Moore’s Law is the iconic driver of electronics progress – but it will continue until physics gets in the way (cooling!)
Research and development is needed as never before
Note: what follows is computer-centric, but…
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Perspective on microelectronic heat fluxH
eat
Flu
x (
W/
cm2)
T, K
Hannemann, Bar-Cohen, and Oktay, ca. 1986
Current Chips
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Technology generations
Timeframe Generation Representative Product Chip Power Module Power Density Rack Power
1945-1955 Historic Specialty Computers
1955 - 1965 Transistor Early Mainframe
1965 - 1975 SSI Mainframe
1975 - 1985 MSI Minicomputer
1985 - 1990 LSI Microcomputer
1990 - 2000 VLSI PC, Notebook, Portables
2000 - ULSI Micro-based Server
Trouble Design care Ignore
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What’s old is new again…
Heroic measures to maintain air cooling…
Heat pipe concepts…
Two-phase system cooling…
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Design / technology drivers
Performance Cost
ReliabilitySize
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Cost of cooling
Cost of cooling a microprocessor, Intel
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Intel’s inflection
X86 power dissipation
0
10
20
30
40
50
60
70
80
90
100
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Year of Introduction
Chi
p Po
wer
(W)
486 PentiumPentium 3
Pentium 4
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Chip power trends
High Performance Chip Power (W)
0
50
100
150
200
250
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Year of Release
W
SIA 1993NTRS 1999NTRS 2002
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Heat flux trends at chip level
Chip Heat Flux
0
10
20
30
40
50
60
70
80
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Year of Introduction
W/c
m2 SIA 1993
NTRS 1999NTRS 2002
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A new problem: machine-room heat density
Data from Amdahl, Compaq, Dell, HP, IBM, SGI, Sun, Unisys, Lucent, Nortel, and Cisco
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Key challenges: large systems
Solutions for very high chip powers (100 – 200W)
High reliability / availability
Rack-level cooling
Machine-room cooling
Cost management
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Key challenges: office systems
Cost / performance microprocessors will reach 80 – 100W within 2 years
Air cooling must be optimized
Acoustics
Reduced cost
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Other challenges
Telecom systems: central offices already stretching power limits
Photonic components provide very serious cooling challengeThermal control at heat fluxes ~ 2 x 103 W/cm2
Performance very sensitive to temperature
Harsh environmentsAutomotive
Telecom
Military
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Research areas
Optimized fluids for liquid coolingMaterials for package construction / thermal spreadingPhase change materials for transient applications
High static pressure, low acoustic noise blowersMicro heat pipe structuresTwo-phase cooling approachesMEMS components for liquid / two phase cooling
Small-footprint liquid cooling systemsPackage-scale jet impingement / spray cooling Advanced, integrated thermal design toolsFrame and rack coolersEquipment room thermal design
Materials
Devices
Design
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Conclusion
The importance of thermal management in electronics devices and systems has waxed and waned over the past 50 years
Current technologies and applications are once again providing aserious challenge – perhaps show-stopping – to heat transfer engineers
Breakthroughs are needed in advanced cooling technologies (and pragmatic design!) at all levels