high voltage power igbt modules
TRANSCRIPT
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High Power Density IGBT Module High Power Density IGBT Module for High Reliability Applications for High Reliability Applications
D.J. Chamund, L. Coulbeck, D.R. Newcombe, P.R. Waind
Presented by: Peter Waind Peter Waind
High Power Density IGBT Module High Power Density IGBT Module for High Reliability Applications for High Reliability Applications
D.J. Chamund, L. Coulbeck, D.R. Newcombe, P.R. Waind
Outline
Ø Ø Introduction Introduction
Ø Ø Basic IGBT Module Structure Basic IGBT Module Structure
Ø Ø Module Reliability Module Reliability
Ø Ø Technologies for increased power density
Ø Ø Conclusion
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Basic IGBT Module Structure Basic IGBT Module Structure
Technologies for increased power density
Objective
Ø Ø Quantify Quantify a a range range of of technology technology
Increase Increase power power density density without without
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technology technology solutions solutions to to: :
without without adversely adversely effecting effecting reliability reliability
IGBT Module 4
G
E
C
Schematic of Construction
Epoxy
Heat Sink
Heat Sink Compound
Base plate
Solder Copper
Ceramic Copper Track
Silicon
Silicone Gel Temp gradient
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Schematic of Construction
Epoxy
Heat Sink
Heat Sink Compound
Base plate
Solder
Copper
Ceramic
Silicone Gel
Reliability Constraints
Failure Failure Mechanisms Mechanisms Ø Ø Random Random Failures Failures
• • Latent Latent defects defects
• • Cosmic Cosmic Rays Rays
Ø Ø Wear Wear Out Out failures failures
• • Wire Wire bond bond lifting lifting
• • solder solder cracking cracking
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− =
stress use
a
T T k E AF 1 1 exp
B
j T A N
∆ =
Arrhenius equation
Internally derived model
Coffin‐Manson equation
Examples of wear out failures
Wire Bond failure
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Examples of wear out failures
Solder joint failure
5 µm
Failure Produced in RAPSDRA programme
Example of Random Failure Example of Random Failure
Cosmic ray failure site Cosmic ray failure site
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Failure Produced in RAPSDRA programme
Example of Random Failure Example of Random Failure
Summary for maintenance of reliability
Ø Ø For random failures For random failures – – maintain or reduce the maximum junction temperature maintain or reduce the maximum junction temperature
Ø Ø For wear out For wear out – – maintain or reduce the delta T maintain or reduce the delta T
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Summary for maintenance of reliability
maintain or reduce the maximum junction temperature maintain or reduce the maximum junction temperature
maintain or reduce the delta T maintain or reduce the delta T
Increase Power Density Increase Power Density
Ø Ø Application specific device characteristics Application specific device characteristics
Ø Ø Increased current rating per silicon chip Increased current rating per silicon chip
Ø Ø Increased Increased junction junction temperature temperature
Ø Ø Advanced Advanced cooling cooling
Ø Ø Increased Increased active active silicon silicon area area
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Increase Power Density Increase Power Density
Application specific device characteristics Application specific device characteristics
Increased current rating per silicon chip Increased current rating per silicon chip
temperature temperature
area area
Application specific device characteristics 11
Application specific device characteristics
Increase current rating per chip Increase current rating per chip
NPT
Vertical structures
p Electric field
n
Doping Profile
Soft Punch Through enables reduction in silicon thickness
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Increase current rating per chip Increase current rating per chip
SPT
Vertical structures
p
Electric field
n
Buffer
n p
Soft Punch Through enables reduction in silicon thickness
Increased current rating per chip Increased current rating per chip
0
20
40
60
80
100
120
0
Collector current, Ic
Optimised emitter design, such as trench gate, can also reduce on‐state losses allowing for increased current rating
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Increased current rating per chip Increased current rating per chip
3.3kV IGBT Forward Characteristics, 125°C, single chip
1 2 3 4 5 6
Collectoremitter voltage Vce
Trench SPT DMOS SPT
Optimised emitter design, such as trench gate, can also state losses allowing for increased current rating
Increased current rating per chip Increased current rating per chip • • Effect of Switching Frequency Effect of Switching Frequency
– – Headline current rating is a DC rating Headline current rating is a DC rating
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3.3kV Modules
Increased current rating per chip Increased current rating per chip Effect of Switching Frequency Effect of Switching Frequency
Headline current rating is a DC rating Headline current rating is a DC rating
Increased Tj
Although increase in Tj will increase power density
This is against criteria to maintain reliability
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Although increase in Tj will increase power density
This is against criteria to maintain reliability
Advanced cooling
Ø Ø Eliminate layers to reduce overall thermal resistance Eliminate layers to reduce overall thermal resistance
Ceramic substrates mounted directly onto heat
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Eliminate layers to reduce overall thermal resistance Eliminate layers to reduce overall thermal resistance
Ceramic substrates mounted directly onto heat‐sink
Advanced cooling
Construction Thermal Resistance
(junction –heat sink) Standard 21°C/kW
Integrated heat sink
7°C/kW
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Thermal Resistance
(junction –heat sink)
DC Current (∆Tj = 45°C)
C/kW 657 A
C/kW 1302 A
Increase active silicon area
EPD 500A 3.3kV chopper module
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Increase active silicon area
EPD 500A 3.3kV chopper module
Std. subst
EPD subst
EPD 2 subst
Increase active silicon area: R
Module Construct
IGBT Rth jn. to case (°C/kW)
Rth case to heatsink (°C/kW)
Standard 12 8
EPD 9.6 8
EPD 2 8 8
Rth of a 140mm x 130mm 3.3kV single IGBT Rth of a 140mm x 130mm 3.3kV single IGBT module module
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Increase active silicon area: R th benefit
Rth case to heatsink C/kW)
Rth jn. to heatsink (°C/kW) 20
17.6
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Rth of a 140mm x 130mm 3.3kV single IGBT Rth of a 140mm x 130mm 3.3kV single IGBT module module
Increased active silicon area Increased active silicon area
Frequency rating
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Increased active silicon area Increased active silicon area
Wear out life of EPD
Increased active silicon area Increased active silicon area
Inductive switching
• • Typical EPD switching waveforms for a 500A Typical EPD switching waveforms for a 500A 3.3kV chopper module @125 3.3kV chopper module @125
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Increased active silicon area Increased active silicon area
Short circuit test
Typical EPD switching waveforms for a 500A Typical EPD switching waveforms for a 500A 3.3kV chopper module @125 3.3kV chopper module @125° °C. C.
Conclusion
• • Techniques for increasing current density have been discussed Techniques for increasing current density have been discussed
• • Data Data sheet continuous current rating does not include switching sheet continuous current rating does not include switching losses and hence current de losses and hence current de rating should be considered when rating should be considered when operating in switch mode operating in switch mode
• • We have demonstrated that better utilisation of module area is We have demonstrated that better utilisation of module area is an effective way of increasing power density an effective way of increasing power density
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Techniques for increasing current density have been discussed Techniques for increasing current density have been discussed
sheet continuous current rating does not include switching sheet continuous current rating does not include switching rating should be considered when rating should be considered when
We have demonstrated that better utilisation of module area is We have demonstrated that better utilisation of module area is an effective way of increasing power density an effective way of increasing power density