Thermosciences DivisionMechanical Engineering Department

Stanford University

Ken Goodson

Microscale Thermal Engineering of Electronic Systems

Key Points

3. Microscale Technologies for Heat and Power Management

2. Nanothermal Devices for Information Technology

IBM

1. Self Heating of Transistors and Interconnects

15 µm

silicon

Solid-state EO

pump

IBM Zurich / Stanford

Microprocessor Thermal Challenges

Siemens

1 µm

ESDMetal 1 (AlCu)

W-plug

TiNThermaldamage

n+ Silicon Diffusion Region0.2 µm

Silicon Dioxide

Metal HeatingTexas Instruments

IBM

Novel Materials

Strained Silicon / Si Ge

Novel Geometries

UC Berkeley/AMD

NanotransistorsGate

Source Drain

Tbody

Thin Body SOI

Source Drain

Gate

SiO2

Si substrate

Classic Bulk FET

Lch

Gate

Strained-Si FET

DrainSource

Si substrate

Graded SiGe

Relaxed SiGe

Strained-Sichannel

GateSource Drain

Gate

Gate

Double-Gate SOI(Purdue, IBM)

FinFET(UC Berkeley, AMD, IBM)

Source

DrainTbody

Transistor Electrothermal Physics

IBM

225 nm

Material boundary with roughness η

electron

d

lattice wave

phononωh=E

λ

Λ

dopantatom phonon

intense electron-phonon

scattering

High ElectricField

Hot Electrons(Energy E)

Acoustic PhononsAcoustic Phonons

τ ~ 0.5psE < 50 meV

Optical PhononsOptical Phonons

τ ~ 10 ps

τ ~ 0.1psE > 50 meV

High ElectricField

Hot Electrons(Energy E)

Hot Electrons(Energy E)

Heat Transferto Package

Heat Transferto Package

Heat to Package

Acoustic PhononsAcoustic Phonons

τmeV

Optical PhononsOptical Phonons

τ ~

τ ~ 0.1psmeV

∆T In

crea

se (K

)

Power Q

’ (µW/µm

)

Channel Length L (nm)

Approximate Impact of DeviceScaling on Peak Phonon

Temperatures

Pop, Banerjee, Dutton, Goodson,Proc. IEDM 2001

field

Transistor Simulation Regime Map

Drif

t Diff

usio

n

BTE

Mom

ents

Mon

te C

arlo

& B

TE

Mon

te C

arlo

with

Qua

ntum

Mod

els

Stratto

n (1962)

Bloetekjaer (1970)

Baccarani (1985)

Rudan (1986)Jacoboni (1983)

Fischetti (1988)

Electrons Full

Qua

ntum

Nanotransistor Regime

~1 nm~5 nmλ

~100 nm~5 nmMFP

phononselectrons

Datta,

Lundstrom (1995)In progress

Latti

ce

Isothermal

Atomistic

Diffusion

BTE or Monte Carlo

BTE withWave models

much work

Wachutka

(1994) Shur (1990)

Apanovich (1995)

Sverdrup, Ju,

Goodson (2000)

Lai, Majumdar

(1995) Research needs for the future

Electron Drift& PhononGenerationat 40kV/cm

• Monte Carlo, 300 electrons at 300 K• Electric Field starts at 0.5 ps• Eavg jumps from 39 meV to 290 meV

Thesis work ofEric Pop, 2003

Phonon Emission

Interconnect Thermal Management

Temperature Contour Plot (50 nm technology node)

209 °C209 °CGlobal WiresGlobal Wires

The temperature rise in interconnects is small now, but compounding trends in the ITRS roadmap lead to a tremendous increase at the 70 nm node beyond

low-k dielectric materialsincreasing current densities and aspect ratiosincreasing number of interconnect layers

0 2 4 6 8 10

120

140

160

180

200

220

Tem

pera

ture

[o C]

Distance from Substrate [µm]

35 nm

50 nm

70 nm

100 nm

130 nm

180 nm

Student: Sungjun Im. Sponsor – MARCO 7.1

ILD

ILDMETMET

2 Nkdd j~ ηρPeak ∆T

Tem

pera

ture

Ris

e (o C

)

0

100

50

IBM Zurich: Vettiger, Binnig Stanford: King, Kenny, Goodson.See King et al., Applied Physics Letters 78, 1300 (2001)

Stanford University Micro- and NanoMechanicsZurich Research Laboratory

Nanoscale Thermal Data Storage

Ibias

Data Reading

“0”∆T ~ 5 K

Ibias

“1”∆T reduced

Ibias

Data Writing

∆T ~ 300 K

Cantilever Array100 nm

Microrocessor Thermal Management

Microprocessor heat sinks are 3000 times larger and heavier than the chip

Power Delivery~1 cm3

ASICs~1 cm3

Heat Sinks,Heat Pipes,Vapor Chambers

~ 102 cm3

~10-1 cm3

RAM~10-1 cm3

Video~10-1 cm3

They crowd away power delivery components, ASICs, RAM, and Video

HOTSPOTS

Interdisciplinary Grand Challenge:Integrated Power Delivery & Heat RemovalGroups of Goodson, Kenny, Santiago, Saraswat, Stanford Mechanical Engineering

Groups of Thompson & Troxel, MIT Materials and Electrical Engineering

Thermofluidic Module with Solid-State Pump (Sponsors: Intel & DARPA)

Thermofluidic Mixed-Signal Power Module (Sponsors: SRC/MARCO & DARPA)

Mixed Signal Chip

Fluidic I/OPhotonic I/O RF

Integrated MEMSSensing

ElectricalConnections

Fluidic Cooling

Mixed Signal Chip

Fluidic I/OPhotonic I/O RF

Integrated MEMSSensing

ElectricalConnections

Fluidic Cooling

Fluid

Mixed Signal Chip

ElectricalConnections

Integrated EOPump/controller

targeted, on-demandmicrochannel cooling

Free I/OSurface

ElectroOsmotic Microchannel Cooler Sponsors: DARPA, Intel, AMD, Apple. Trans CPMT (2002). Best Paper SemiTherm 2001

Heat Rejector

Micro Heat Sink

2002: Apple Dual Processor Demo2001: 30 W Demo, 1 cm2 (Intel)2002: 100 W Demo, 1 cm2 (Intel)

2003: AMD Demo2002: 150 W Demo, 4 cm2 (Intel)

2002: Laptop Demo

EO Pump

ElectroOsmotic Pump

Microchannel Heat Sink

Stanford/Intel 100 W DemoEO Pump Flowrate ~ 20 ml/min

PIs: Goodson, Santiago, Kenny, Stanford ME

+ +++++

Silicondioxide

wall

Chargedouble-layer Charge Double

Layer

+ -High-PressureLiquid Pumping

~ 50 nm

Pyrex seal

ChannelsIn silicon

Si chip

Thermalattach

ElectroOsmotic Pumps With groups of Santiago and Kenny, Stanford Mechanical EngineeringSponsor: SRC/MARCO, DARPA

1 cm1 cm

Vd

p 2max32εζ

=∆

µ−

−µεζ

=)ra(

dxdpE)r(u

22

lVAQ

µεζ

=max•Very high volume to flowrate ratio

•Stanford pump performance (Feb 2002)

Pmax ~ 2 atm, Qmax ~ 40 ml/min, Vol. ~ 2 cm3

EOF

+ + + +++ ++ ++ + +++ ++

Glass or fused-silica capillary wall

Charge double-layer

Deprotonated silanolgroups

+ -

Idealized pore channel:

Free-standing pump

• Founded in 2001 by Stanford Profs. Ken Goodson, Tom Kenny, Juan Santiago, Mechanical Engineering

• 24 employees (Feb 2003) with engineering expertise including chemical, mechanical, packaging, thermal, & fluidic specialties

• Experienced management and directors drawn from Intel, Dell, Corning, Silicon Light Machines.

• Focussing on reliability demonstration, product implementation, collaboration with computer manufacturers

2370 CharlestonMountain View, CA 94043

www.cooligy.com

Cooligy develops thermal management components based on electro-osmotic pumps and novel microscale heat exchangers

Heat Rejector

Micro Heat Sink EO Pump

Concluding Remarks• The next decade of IC research & development will bring

solutions to “secondary” challenges associated with Moore’s Law, such as power delivery, heat removal, and package integration.

• IC thermal management problems will have lengthscalesspanning six orders of magnitude, from 10 nm in nanotransistors to more than 10 cm at the package level.

• Novel materials and geometries are increasing micro/nanoscale on-chip thermal resistances, leading to hotspots in metallization and interconnects.

• Circuit design focuses computation on the chip, yielding mm-scale hotspots that dramatically increase the thermal resistance from the chip to the package.

Alumni (1999-2002)Prof. Mehdi Asheghi Carnegie Mellon University (ME)Prof. Dan Fletcher UC Berkeley (Bioengineering)Prof. Bill King Georgia Tech (ME)Prof. Katsuo Kurabayashi University of Michigan (ME)Prof. Sungtaek Ju UCLA (ME) – with IBM until Fall 2003Prof. Kaustav Banerjee UC Santa Barbara (EE)Dr. Uma Srinivasan XeroxDr. Per Sverdrup Intel Dr. Peng Zhou CooligyDr. Maxat Touzelbaev AMD

Goodson Microscale Heat Transfer GroupThermosciences Division, Mechanical Engineering Department, Stanford

Current Students and Post-Docs (AY 2002/2003)Dachen Chu (Physics) Monikka Mann (ME) Xuejiao Hu (ME) Sanjiv Sinha (ME)Sungjun Im (Materials Science) Evelyn Wang (ME)Kevin Ness (ME) Ankur Jain (ME)Jae-Mo Koo (ME)Yue Liang (ME) Dr. Linan JiangAngie McConnell (ME) Dr. Abdullahel BariEric Pop (Electrical Engineering) Dr. Samuel Graham (Visitor from SNL)