Thermal challenges in IC’s: Hot spots — passive cooling ...meptec.org/Resources/04 Honeywell...

Thermal challenges in IC’s: Hot spots — passive cooling and beyond

Devesh Mathur, Ph.D.Andy Delano, Ph.D.

Honeywell Electronic MaterialsSpokane, WA, USAFebruary 15, 2007

2 Devesh Mathur & Andy Delano HONEYWELL – CONFIDENTIAL 2/15/2007 MEPTEC

Overview

• Motivation

• Where are the thermally challenged IC’s?

• Cooling IC’s today

• Cooling IC’s in the future

• How do we get there?

• Conclusions


Microprocessor Applications

IC’s are pervasive in various applications


All Rely on Chips

10 billion square inches of silicon forecast for 2009


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Putting the Heat Flux Challenge into Perspective

Sunlight on a Tropical Beach


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1 Megaton at 1 mile


Shuttle Re-entry


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Rocket Nozzle Throat

1 Megaton at 1 mile


Shuttle Re-entry


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Rocket Nozzle Throat

1 Megaton at 1 mile


Shuttle Re-entry

Tomorrow’s Microprocessors

The thermal challenge in an IC is a truly daunting problem


Most heat leaves through center 15% of the spreader’s surface area

Motivation: CPU Heat Flux is High

IR image of an actual processor


ITRS Power Predictions

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2002 2004 2006 2008 2010 2012 2014 2016 2018Year

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130 nm 90 nm 65 nm 45 nm 32 nm

Motivation: CPU Power is Steadily Increasing

Flux at the core continues to rise despite design innovation


Central Processor Unit(s)

ChipsetWhere are the thermally challenged IC’s?

AMB Memory

Graphics Processor Unit (GPU)Picture of a Workstation

Thermal solutions are required for the CPU and ASIC’s


Memory: AMB IC

• IC: Bare die• Power: 4-8 Watts• Airflow: System dependent,

usually compromised- Sometimes cards are

perpendicular to flow- In servers and workstations,

many cards are packed densely together

• Thermal Solution: TIM and a heat spreader

AMB IC is HOT

Up to16 Memory Cards

Memory cards require thermal solutions and system level attention


The Most Critical Heat Pathways

Heat Spreader

Thermal Interface Material

The highest heat fluxes travel through 0.20 C/W of the total budget


Typical Thermal Budget

TIM 1, 0.050

Heat Spreader, 0.100

TIM2, 0.050

Heat Sink Base, 0.100

Heat Sink Fins, 0.100

Pre Heat, 0.100

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{


Classical Packaging Limits

• Classical Package consists of:- TIM1- Heat Spreader- TIM2

• Typical limitations- TIM1

Heat Spreader FlatnessHeat Spreader Surface

- Heat SpreaderSpreading ResistanceCTE mismatch

- TIM2Heat Spreader FlatnessHeat Spreader Surface

θ junction to heat sinkwhere we are vs. best in class

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Typical Modeled Best in Class

˚C/W

Room to improve classical package with improved technology


Materials Roadmap for Critical Heat Pathways

Heat Spreader


HEM produces and develops products for critical heat pathwaysThe products control at least 0.20 C/W of the total budget


-2004------------------------ 2006---------------------------2008+


Memory Module Heat Sink: Thermal Modeling

Actual Memory Heat Sink

3D CAD Model for Mechanical FEA Analysis

Is TIM1 important to the AMB?


FEA results predict >10 ˚C reduction on AMB chip, allowing superior performance

Honeywell PCM45 Competitor’s MaterialTIM 1 Performance: Memory Module


Honeywell’s TIM’s*

HEM representative products cover a wide performance range to help address thermal challenges

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PCM45F- PadPCM45F-SP PCM- Next Generation

APS Indium- Combo

(Polymer Filled) (Polymer Filled)

(Advanced Polymer Solder) (Pb Free- Metallic)

*Actual Data may vary in application. ASTM D-5470


Collaboration is key to Innovation

IndustryAcademia

People

External Forces Competition

Rapid and fundamental innovation requires increased collaboration


• Products - Optimized particle TIMS- CNT TIMS- Advanced Heat Spreaders

Collaboration: example CTRC• Path

- Attend bi-annual CTRC meetings to review work

- Determine and support relevant technologies

- Productize

• Purpose: Long term research and development in the area of high-performance heat removal from compact spaces

- NSF Industry/ University cooperative research center at Purdue University

• Progress- Member since 2002- Hired CTRC graduate

Boiling Research

Particulate TIM ModelsSource: CTRC, Purdue. Used with permission.

Industry issues worked on fundamentally to address challenges


Nextreme’s eTEC for Hotspot Cooling

Thermoelectrics: example Nextreme Active Cooling

• Thin film thermoelectric device operates between the heat spreader and IC

• Hot spots are addressed with refrigeration- Heat flux into heat spreader

increases, however, hot spot temperature is reduced

- Some additional power is required

• Challenges- Improving TE materials- Understanding Reliability

Source: Nextreme, used with permission.

With improved materials and reliability, thermoelectric devices could revolutionize hot spot cooling


Improving the Heat Spreader Improves the performance of everything downstream

• Standard Heat Spreader• Tmax = 81.2 ˚C

• Enhanced Heat Spreader• Tmax = 63.4 ˚C

New: Honeywell’s Active Heat Spreader

Significant (17.8°C) reduction over current technology


Other Innovations

• Power limitations for chip architects

• Software and threading innovation

• Data center power balancing

• Discrete device computing

• Multi die and multi core

• Feedback loops, throttling, and thermal shutdown

Smart chip & system design can also address thermal challenges


Thermal Management at the IC Level

• This technique is currently used in:- mobile computers- CPU’s- AMB’s (DIMMs)

Power management can improve thermals, but will reduce performance

IC T

empe

ratu

re

Shutdown

Power rationing

Fan speed control

Permanent thermal damage

!!Computing errors!!

Reduced performance and reliability

In-spec performance and reliability

Low dB acoustics


Summary

• Thermally Challenged IC’s found throughout modern computers- CPU- ASIC’s

GPUMemoryChipsets

• Overall Heat Flux and Hot Spots are pushing the limits of today’s products

• Some of today’s cutting-edge products address the thermal challenge today

• Next generation products offer hope. Collaboration is key.

Innovation in thermal management will enable better performance

Thermal challenges in IC’s: Hot spots — passive cooling ...meptec.org/Resources/04 Honeywell...

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