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From Fit for Standard to Fit for Application
Eckhard Wolfgang, ECPE e.V.
Nuremberg, Germany
eckhard.wolfgang@ecpe.com
Acknowledgements: Guenter Engel (CeraCap Engel KG)
Uwe Scheuermann (Semikron)
Werner Kanert (former Infineon)
Nando Kaminski (Univ Bremen)
Martin Rittner (Bosch)
Markus Thoben (Infineon)
Johann Kolar (ETHZ)
1
The Basic Question
3
Is our product
"sufficiently reliable"
in the application?
Have I passed my
qualification tests
according to the
standard?
Fit for use
Fit for standard
RV – A Knowledge-Based Approach
4
material
process
design
temperature
humidity
V, I others
mission profile
failure mechanisms
system components
RV is a knowledge-based approach:
Knowledge of the conditions of use (mission profile)
Knowledge of the failure mechanisms and failure modes
Knowledge of acceleration models for the failure mechanisms
Outline
Introduction
AECQ Standards
Robustness Validation
Mission Profile
Estimation of Lifetime
ECPE Guidelines AQG 324 for Power Module Qualification
Qualification of DC-link Capacitors for Automotive Use (ZVEI)
Power Electronics Integration
Paradigm Shift
Summary
5
AECQ Standards
6
AEC - Q101 - Rev – D1
September 6, 2013
FAILURE MECHANISM BASED
STRESS TEST QUALIFICATION
FOR
DISCRETE SEMICONDUCTORS
IN AUTOMOTIVE APPLICATIONS
Zero Failure out of 77 samples means:
The probability is 90% that the accepted lot contains
up to 0.14% = 1.400 ppm faulty parts
This criterion does not fit to the needed automotive
low ppm-level of todays applications
Appendix 7: Guidance on Relationship of Robustness Validation to AEC-
Q101
A qualification method has recently been developed with the intent of
addressing application specific operations. Called Robustness Validation,
this method considers the specific environmental and operational
application conditions and the customer lifetime requirements to calculate
the minimum required set of qualification test conditions, durations
and sample sizes. Ref [ 1 ]
Robustness Validation
The new 'test to fail' qualification approach
(instead of a 'test-to-pass'), is a paradigm shift from
'Fit for Standard' to 'Fit for Application'.
Robustness Validation generates knowledge on
the relevant component failure mechanisms that
may occur at the boundaries of the specification
limits.
9 3D-PEIM June 27. 2018
Mission Profile
A Mission Profile is a simplified representation of relevant conditions to
which the Device/ Component production population will be exposed in
all of their intended application throughout the full life cycle of the
component.
10 Ref [4 ]
Mission Profile: A Gordian Knot
11
1st and 2nd Tier OEM
Mission Profile
- Drive profiles
- Relevant
stresses
-Type of EM
- Power Module
- Cooler
- Zth
Lifetime Model
of Power Module
1) What is the lifetime of your
Power module? 2) What is your Mission Profile?
3) I cannot tell you because it
is confidential! 4) Then I cannot tell you!
N
∆T
Mission Profile: How to cut the Gordian Knot
12
1st and 2nd Tier OEM
Mission Profile
- Drive profiles
- Relevant
stresses
-Type of EM
- Power Module
- Cooler
- Zth
Lifetime Model
of Component
N
∆T
OEMs calculate the number of
Power Cycles using the
„confidential“ Mission Profile
Bond wire lift-off
Robustness Margin
14
Consolidated Results after Rainflow Counting
0
5
10
15
20
25
30
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Supplier A 2K
Supplier B 2k
Academic A 2K
Supplier C 2k corr.
Supplier D
Supplier E
Delta T
Time
T
Num
ber
ECPE Guideline AQG 324
15
Scope This document defines requirements, test conditions and tests for
validating properties, including the lifetime of power electronics
modules and equivalent special designs based on discrete
devices, for use in power electronics converter units (PCUs) of
motor vehicles up to 3.5t gross vehicle weight.
.
Qualification of Power Modules for Use in Power Elec-
tronics Converter Units (PCUs) in Motor Vehicle
The described tests concern the module design as well as the
qualification of devices on module level (i.e.the assembly),
but not the qualification of semiconductor chips or manufacturing
processes
Ref [ 5, 6 ]
Power cycling reliability of IGBT4
Power Cycling target IGBT5
1.E+04
1.E+05
1.E+06
1.E+07
40 60 80 100 120
delta Tj (K)
no
of
cycle
s
Ref IGBT 4 Tvj 150°C
Page 16
Ref [ 7 ]
PCsec Test Conditions
17
Forward voltage IGBT: UCE,sat MOSFET: UDS Diode: UF
+ 5 % a
Increase in virtual junction temperature swing
∆Tvj
+ 20%
Failure Criteria
18
Power Cycle Test Results with Different
Control Strategies
Source: U.Scheuermann, ESREF 2010
1. Constant timing
2. Constant ΔTbaseplate
3. Constant power dissipation
4. Constant ΔTjunction
Failure criteria
3D-PEIM June 27. 2018 Ref [ 8 ]
Lifetime Models for a certain IGBT module technology showing the
impact of power cycle ton times at a given aspect ratio of the bond loop
Life Time Model/ Reliability Curve
19
Semikron
3D-PEIM June 27. 2018 Ref [ 9 ]
Part of Power Module Test Matrix
Thermal Shock
Contactability
Vibration
UGE,th Gate-Emitter-Threshold Voltage
UGS,th Gate-Source-Threshold Voltage
21
Vibration
Electrical Characterisation E-01 … E-05
Mechanical Characterisation M-01, M-02
High
humidity, T
High
temp.
Charge,
discharge
Mechanical Characterisation M-01, M-02
T-shock
Electrical Characterisation E-01 … E-04
6 capacitors are tested for each of the 4 groups
Short
circuit
DC-link film C: Testplan
24 Ref [ 11 ]
Integrated DC-link Capacitor Systems for HP IGBT Modules
26
SBE - Infineon
From Top:
- Control board
- IGBT module
- Liquid cold plate
- Film capacitors
EPCOS - Infineon Ref [ 13 ]
Ref [ 14 ]
28
Paradigm Shifts
Paradigm shifts Industry needs
Power
devices
SiC and GaN will become more
and more qualified for several
subsystems, like 48 V board net
and LED headlight
Learning curve for WBG-
devices: optimizing special
properties
Packaging &
Substrates
For SiC- and GaN- devices RF
compatible packages and
low inductive interconnects are
necessary. This calls for new CAD
tools as well.
Learn about:
RF interconnections
New materials
Smaller geometries
Testing capabilities (RF,
size)
Power
modules
Low inductive arrangement of
multichip modules
New module designs
with precautions
regarding attachment to
RF PCB and
heat sinks 3D-PEIM June 27. 2018
29
Cooling Two-phase cooling will become
more important as well as double-
side and immersion cooling
Integrated systems are
needed to avoid TIM
interfaces as much as
possible
Reliability From "Fail safe" to "Fail operation"
by using Fault tolerant designs
Intensive use of "by-
wire" systems
48 V board
net
The many more electronic
subsystems consume more power
Adequate connectors
and
test fixtures
Sensors High reliable and for automotive
qualified sensors for many (new)
functions
Placing and wiring of
EMI compatible
sensors
calibration of sensors
Testing More and better lifetime models for
accelerated testing
New RF capable test
equipment
3D-PEIM June 27. 2018
Summary 1
30
German car makers, 1st and 2nd Tiers developed a guide line for
“Qualification of Power Modules for Use in Power Electronics
Converter Units in Motor Vehicles”
The original idea was to be able to compare “apples with apples”
The Robustness Validation Process was the basis for the guideline
It is a knowledge based process
Conditions of use (Mission Profile)
Physics of failure
Acceleration models for failure mechanisms
It is difficult to get mission profiles
The solution is an active cooperation between OEMs and Tiers
Standardized tools for modeling and simulation are prerequisites
Summary 2
31
A similar approach was chosen for the guideline on
“Qualification of DC-link Capacitors for Automotive Use”
The sample size for tests is 6 only
End-of-life tests should be used whenever it is possible
Beside the use of WBG power devices – SiC and GaN – integration
is the most promising goal in future
An data sheet is proposed as well as a Delta-qualification matrix
Both guidelines can be downloaded by ECPE (PM) and ZVEI (DC-link)
There will be quite a few paradigm shifts in future which will have
great impact on reliability and manufacturing
References/ 1
32
[ 1 ] http://www.aecouncil.com/Documents/AEC_Q101_Rev_D1_Base_Document.pdf
[ 2 ] Handbook for Robustness Validation of Automotive Electrical/Electronic
Modules
http://standards.sae.org/j1211_201211/ and
https://www.zvei.org/en/subjects/mobility/robustness-validation-general/
[ 3 ] E.Wolfgang, Ten years of Robustness Validation Applied to Power Electronics
Components, IWIPP 2017
http://ewh.ieee.org/soc/cpmt/presentations/cpmt1704a.pdf
[ 4 ] M. Thoben, K. Mainka, R. Bayerer, I. Graf, M. Münzer, From vehicle drive
cycle to reliability testing of Power Modules for hybrid vehicle inverter
https://pdfs.semanticscholar.org/fc43/
763c8dcbbed39496a925aa18f29424ae8f57.pdf
[ 5 ] M. Rittner, M. Thoben,K.Kriegel, Automotive: Qualification Routines
for Power Electronics Components in Electrified Powertrains,
CIPS 2018 (will be available on IEEE Xplore)
[ 6 ] AQG 324: ww.ecpe.org/news-projects/network-news/current/details/
?tx_ttnews[tt_news]=502&cHash=ed72de196165af05572467c04f03de87
References/ 2
33
[ 7 ] Bayerer, R.: Advanced packaging yields higher per formance and reliability
in power electronics, Microelectronics Reliability 50 (2010) 1715-1719
[ 8 ] Scheuermann, U., Schuler, S.: Power cycling results for different control
strategies, Microelectronics Reliability 50 (2010) 1203-1209; IEEE Xplore
[ 9 ] U.Scheuermann, R.Schmidt, A New Lifetime Model for Advanced Power
Modules with SinteredChips and Optimized Al Wire Bonds, PCIM Europe 2013
[ 10 ]Reliability of Power Electronic Converter Systems, Ed. by H. S. Chung,
H. Wang, F. Blaabjerg and M. Pecht; IET Power and Energy Series 80,
ISBN 978-1-84919-902-5 (PDF)
[ 11 ] Qualification of DC-link Capacitors for Automotive Use:
tps://www.zvei.org/fileadmin/user_upload/Presse_und_Medien/Publikationen/
2017/Juli/Qualification_KFZ-DC-Link-Capacitors/
ZVEI-Qualification_KFZ-DC-Link-Capacitors_V2_2017.pdf
[ 12 ] https://en.tdk.eu/download/1530392/fdf3adf69e5de3da18240716dd985ca2/
ceralink-kondensatoren-pb.pdf
[ 13 ] https://en.tdk.eu/tdk-en/373562/tech-library/articles/applications---cases/
applications---cases/space-saving-dc-link-solution/171874
References/ 3
34
[ 14 ] SBE- DC Link system for the Infineon HP Drive 6 Pack
http://www.sbelectronics.com/products/infineon-hp-drive-6-pack-compatible-
test-kits/
[ 15 ] https://www.pes-publications.ee.ethz.ch/uploads/tx_ethpublications/
__CIPS_18_Keynote_FINALFINAL_270318.pdf
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