solving heat management issues with thermally conductive plastics

SOLVING HEAT MANAGEMENT ISSUES

IN ELECTRONICS APPLICATIONS

USING THERMALLY CONDUCTIVE PLASTICS

06.17.2015 Copyright © 2015 Momentive Performance Materials Inc. All rights reserved.

Webinar

PRESENTED BY:

ALLISON HOWARD YESKE DR. CHANDRA RAMAN

GLOBAL MARKETING MANAGER GLOBAL TECHNOLOGY LEADER

Copyright © 2015 Momentive Performance Materials Inc. All rights reserved.


• Review the basics of heat transfer

• Share simplified models of heat dissipation from chips in three electronic

devices

• Show how thermally conductive plastics can be used to create more

favorable operating conditions

• Present specific benefits of BN-based thermally conductive plastics in

electronics applications

AGENDA

3 Copyright © 2015 Momentive Performance Materials Inc. All rights reserved.


Mega-Trends

• Increasing miniaturization with more functionality

• Reducing weight

• Introducing more complex designs with easier assembly

4

Thermally conductive plastics (TCP)

containing boron nitride (BN) can

help solve today’s challenges





devices





AGENDA



Basics of Heat Transfer

Three Modes of Heat Transfer

6

TH

TC

𝑄 = 𝑘𝐴(𝑇𝐻 − 𝑇𝑐)

𝑙 Conduction

𝑄 = 𝑕𝐴(𝑇𝐻 − 𝑇𝑐) Convection TH

TC

𝑄 = 𝜖𝜍𝐴(𝑇𝐻4 − 𝑇𝐶

4) Radiation TH

TC


7


Theoretical Solution of Heat Transfer

Heat transfer equation


Bottom view

Top view

Element Model Inputs

Heat Source 2.4 W

Heat transfer

coefficient (h) 4.7 W/m2K

Emissivity e = 1

Plastic plate with heater

Top and bottom surfaces dissipate heat

by convection and radiation

𝜌𝐶𝑝𝜕𝑇

𝜕𝑡= 𝛻 ∙ 𝑘𝑖𝛻𝑇

Boundary conditions

−𝑘𝑖𝜕𝑇

𝜕𝑥𝑖= 𝑕 𝑇 − 𝑇∞ + 𝜍𝜖 𝑇4 − 𝑇∞

4

8

Temp

(oC) Predicted Actual

Heater 125 124

Top

surface 119 110

Neat resin – 0.35 W/mK


Plastic Plate Case

Heat transfer calculations closely reflect reality


9

Temp

(oC) Predicted Actual

Heater 93 96

Top

surface 83 80


Plastic Plate Case


TCP housing: 2 W/mK (X-Z); 0.6 W/mK (Y)

Heat transfer calculations closely reflect reality



devices





AGENDA



Set top box



Three application case studies

Mobile phone Wireless router


MOBILE PHONE CASE STUDY

Chip 1

Chip 2

Chip 3

Battery

Boundary conditions


Battery 0.1 W

Chip 1 0.5 W

Chip 2 0.2 W

Chip 3 0.2 W

Bottom face (image above)

3.8 W/m2K, e = 1.0



Max Temp (oC) Predicted

Chip 1 67

Chip 2 72

Chip 3 72

Baseline case: unfilled plastic housing (0.2 W/mK)


SET TOP BOX CASE STUDY

Boundary conditions


Heat Source 3 W

Wall thickness 2 mm

Heat transfer coefficient

5 W/m2K

Emissivity e = 0.9

Box dimensions 50 mm x 50 mm x 100 mm

Heat

source

Steel heat

spreader

Plastic

housing




Chip 94

Bottom surface 82

Baseline case: unfilled plastic housing (0.2 W/mK)


WIRELESS ROUTER CASE STUDY

Element Heat input

Chip 1 8 W

Chip 2 3 W

Chip 3 3 W

RAM 1 2 W

RAM 2 2 W

Total 18 W

Chip 3

Chip 2

Chip 1

RAM 1

RAM 2

Chips could be mounted on either

• Steel heat spreader (TC = 60 W/mK)

• Aluminum heat spreader (TC = 100 W/mK)


Heat transfer coefficient

5 W/m2K

Emissivity e = 0.9

Box

dimensions 230 mm x 150 mm x 35 mm



Chip 3

Chip 2

Chip 1

RAM 1

RAM 2

Steel heat spreader (TC = 60 W/mK) with

unfilled plastic housing (TC = 0.2 W/mK)

Aluminum heat spreader (TC = 100 W/mK)

with unfilled plastic housing (TC = 0.2 W/mK)

Element Temperature (oC)

Chip 1 89

Chip 2 82

Chip 3 82

RAM 1 80

RAM 2 80

Bottom face 80


Chip 1 99

Chip 2 86

Chip 3 86

RAM 1 84

RAM 2 84

Bottom face 88

DO YOU CONSIDER THE DEVICE

HOUSING TO BE PART OF THE

OVERALL THERMAL MANAGEMENT

SOLUTION?

Tell Us What You Think!



OPTIONS – Pick One

• Yes

• No

• Sometimes

Share your

input now!

Do you and your

peers have the

same opinion?



devices





AGENDA






TCP housing: 3 W/mK (X-Z) ; 0.9 W/mK (Y)


Wide range of TCP

formulations possible

HOW MUCH OF A TEMPERATURE

CHANGE DO YOU EXPECT TO SEE

MOVING TO A THERMALLY

CONDUCTIVE PLASTIC SOLUTION?





• < 10 oC

• 10 - 20 oC

• > 20 oC

Share your

input now!

Do you and your

peers have the

same opinion?



Max Temp

(oC)

Baseline

Neat Plastic

0.2 W/mK

TCP

2 W/mK

TCP

3 W/mK

TCP

5 W/mK

Chip 1 67 49 46 43

Chip 2 72 46 43 40

Chip 3 72 43 37 40

-18o

-26o

-29o

-21o

-29o

-35o -32o

-32o

-24o

Thermally conductive plastics can effectively lower operating

temperatures and potentially reduce failure rates

Note: Test data. Actual results may vary




Chip 1 42

Chip 2 42

Chip 3 40

Aluminum housing (TC = 100 W/mK)

Disadvantages of Al:

• Weight

• Painting required

• Interference with

wireless signals

Very similar to 5 W/mK TCP




Chip 72

Bottom surface 67

-12o

-15o


Thermally conductive plastics can effectively lower operating

temperatures and potentially reduce failure rates




Chip 3

Chip 2

Chip 1

RAM 1

RAM 2

Steel heat spreader (TC = 60 W/mK) with

TCP housing 2 W/mK (X-Z), 0.6 W/mK (Y)

Aluminum heat spreader (TC = 100 W/mK)

with TCP housing 2 W/mK (X-Z), 0.6 W/mK (Y)


Chip 1 77

Chip 2 70

Chip 3 70

RAM 1 68

RAM 2 68

Bottom face 73


Chip 1 87

Chip 2 75

Chip 3 74

RAM 1 72

RAM 2 71

Bottom face 82

-12o

-11o

-12o

-12o

-13o

-6o

-12o

-12o

-12o

-12o

-13o

-7o

Lower

operating

temperatures

with TCP




devices





AGENDA



Various Material Solutions for Thermal Management

Die-Cast Aluminum

Graphite-loaded Plastic

BN- / CoolFX* hybrid filler-

loaded Plastic

Heat Transfer OS OK OK

Electrical Insulation X X EX

Electro-magnetic Interference X X EX

Design Freedom / Parts Integration X OK EX

Light Weight OK EX EX

Mechanical Properties EX OK OK

Color/Aesthetics X X EX

Mass Production Capability X EX EX

Process ability (low abrasion, wear, ease) X** OK OK

Price OK EX OK

** If high volume (100k shots = lifetime of tool)

EX = excellent OK = sufficient X = not sufficient OS = overshot


BN-based plastics offer unique benefits

in thermal management applications

*CoolFX is a trademark of Momentive Performance Materials Inc.

IS ELECTRICAL INSULATION

IMPORTANT FOR THE DEVICE

HOUSING?





• Yes

• No

• Sometimes

Share your

input now!

Do you and your

peers have the

same requirements?

With the proliferation of wireless connectivity, more devices are

transmitting and receiving wireless signals (= electromagnetic waves)

Electrically conductive materials interfere with electromagnetic waves

PRIMER ON EMI & SHIELDING


𝑆 = 20 𝑙𝑜𝑔10𝐸𝑖𝑛𝑐𝐸𝑡𝑟𝑎𝑛𝑠

Incident

Field (Einc)

Absorbed (A)

Reflected (R)

Transmitted Field (Etrans)

(MR)

Where:

• EMI = electromagnetic interference

• MR = multiple reflections

• S = shielding (in decibels)


𝑆 = 20 𝑙𝑜𝑔𝜂0 + 𝜂 2

4𝜂0𝜂+ 20 𝑙𝑜𝑔 1 −

𝜂0 − 𝜂

𝜂0 + 𝜂

2

𝑒−2𝑡

𝛿 𝑒−𝑗𝛽𝑡 + 20𝑙𝑜𝑔 𝑒𝑡𝛿

𝑆 = 𝑅 +𝑀𝑅 + 𝐴

𝑅 𝑀𝑅 𝐴

𝜂 =𝑗𝜔𝜇

𝜎+𝑗𝜔𝜖

𝛿 =1

𝜋𝑓𝜇𝜍

Where:

• 0 is the impedance of free space (~377 )

• is the complex impedance of the medium

• d is the skin depth

• b is the phase constant of the shield material

• S is shielding (in decibels)

CALCULATING SHIELDING

Electrical (volume) resistivity

EMI IMPACT ON SIGNAL STRENGTH


1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E-07 1.0E-05 1.0E-03 1.0E-01 1.0E+01 1.0E+03 1.0E+05

To

tal S

hie

ldin

g (

dB

)

r (-cm)

8.3 dB

30 dB


Housing thickness

2 mm

Frequency 1 GHz

@ 20 dB: signal power reduced

by a factor of 100

Final signal is 1% of

original

@ 10 dB: signal power reduced

by a factor of 10

Final signal is 10% of

original

Thermally conductive and electrically insulating plastics

offer unique benefits in thermal management applications

Typical TCP formulations containing graphite/carbon fiber (30-50 wt%)

WOULD YOU CONSIDER THE

DEVICE HOUSING TO BE PART OF

THE OVERALL THERMAL

MANAGEMENT SOLUTION?





• Yes

• No

• Sometimes

Share your

input now!

Do you and your

peers have the

same opinion?


SUMMARY


• Demands for performance and functionality keep increasing in electronic devices

• Thermally conductive plastics can effectively lower operating temperatures and potentially reduce failure rates

• As number of wireless communication devices grows, potential for signal interference is increasing

• BN-based thermally conductive and electrically insulating plastics offer unique benefits, including strong signal transmission

• BN-based plastics are also lightweight and enable color and design freedom

• Momentive can help solve your thermal management issues and

accelerate new developments

34

Coatings

Follow Momentive on SpecialChem for the latest news about BN-

based thermally conductive plastics and TCP applications

http://polymer-additives.specialchem.com/centers/thermally-conductive-plastics--tcp--containing-boron-nitride



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*CoolFX is a trademark of Momentive Performance Materials Inc.

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solving heat management issues with thermally conductive plastics

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