Innovative Techniques for Thermal …Innovative Techniques for Thermal Characterization and...
Transcript of Innovative Techniques for Thermal …Innovative Techniques for Thermal Characterization and...
Innovative Techniques for Thermal Characterization and Inline-Capable
Thermography-Based Failure Analysis
27 June 2019
Tobias von Essen
Origin
» Founded in 2004 as Fraunhofer spin-off
» Continuous refining of expertise from general reliability to focus on thermal management and thermal characterization
» Today partner of major European electronic industries and full-scale provider for thermal characterization and reliability analyses
» Creative, flexible and multidisciplinary team of physicists, mathematicians, programmers and engineers
» Member and co-founder of the Joint Lab Berlin for Technical Safety
Tobias von Essen
27 June 2019
Nanotest in numbers
» 15 years experience
» 20 research projects
» 20 employees
» 2 laboratory sites
Portfolio Overview
Thermal Analysis Services
» Materials & compounds characterization
» System and package analysis
» Failure detection & localization
» Reliability investigation
Thermal Measurement Equipment
» Thermal conductivity & diffusivity
» Solids to liquids
» Material aging investigation
» Measurement & calibration equipment
Research & Development
» Joint and bilateral research projects
» Non-standard measurement tasks
» Novel method deployment
» Customer-specific solutions
» Thermal consulting & training
» Regular publications and tutorials
Tobias von Essen
27 June 2019
Serv
ices
Pro
du
cts
Develo
pm
en
t
Chip #5, 3.2 kJ, pulse length <9,8 ms
http://www.ti.com/lsds/ti/applications/industrial
Motivation
» Reliability in electronics is
less or more important
» Irreliability often more
expensive than reliability
» Thermal performance is
vital to reliability
» Subject to reliability testing:
› Materials
› Systems
› Processes
» Knowledge is key
27 June 2019
Tobias von Essen
Motivation
27 June 2019
Tobias von Essen
Reliable and contextually valid material data is
required
» Evaluation for material development
» Material selection in electronics development
» Input data for simulation
» Datasheets
» Quality assessment
Electronic components and systems contain
» Semiconductors SiC, GaN, Si, different doping
» Metals cooler, heat spreaders, metallization
» Substrates ceramics, polymers, composites
» Die attaches solders, sinter materials, adhesives
» TIMs silicone-based, metal-based, carbon-based
Substrate
Underfill
Cu
Si Cu
Si
TIM1 TIM1
Solder
Our vision: in one minute to thermal conductivity
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Tobias von Essen
Sample
3ω from lab to
industrial level
Results in
< 1 min
Measurement Principle Schematic
Quick Thermal Material Characterization with Minimum Effort
Feasible Samples
» Liquids
» Gels
» Pastes
» Solids
Material Parameters
» Bulk thermal conductivity
» Thermal diffusivity
TOCS® Three Omega Characterization System
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Tobias von Essen
Sample material is simply applied on the test
chip and measured with a mere button press.
Amplitude of temperature oscillation at the sensor vs. electrical frequency
3ω-measurements of TIM materials
27 June 2019
Tobias von Essen
Sarcon SPG-
30A
silicone compd.
Wacker® P12
silicone paste
Dow Corning®
TC-4525 gap
filler
Dow Corning®
340 heat sink
compd.
Thermal conductivity of epoxy during curing
Tobias von Essen
27 June 2019
→ Thermal conductivity increases from (0.124±0.004) W/(m·K) directly after mixing to
(0.191±0.004) W/(m·K) after 24 hours of curing.
12 mm
epoxy
Curing at RT
Linear Fit of Rth over BLT
ASTM D 5470
Tobias von Essen
27 June 2019
𝑅𝑡ℎ𝑒𝑓𝑓 =Δ𝑇
𝑄
𝑅𝑡ℎ𝑒𝑓𝑓 = 𝑅𝑡ℎ𝑏𝑢𝑙𝑘 + 𝑅𝑡ℎ0
0
1RthBLT
ARth
bulk
eff +
=
Rth
BLT
bulk
1~
The linear fit over BLT bears information about bulk thermal
conductivity and the effective thermal interface resistance
𝑄 =∆𝑇𝑅𝐵
𝑙𝑅𝐵𝐴𝑅𝐵 𝜆𝑅𝐵
Heater
Cooler
sample
T1
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T3
T4
T5
T6
Up
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heat
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(\textit{$\Delta$T}) T3
T4
Rth0.1
Rthbulk
Rth0.2
TIMA®Thermal Interface Material Analyzer
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Tobias von Essen
examples of feasible material samples
selection of available test heads
Material Parameters
» Conform to ASTM-D5470 standard
» Effective and bulk thermal conductivity
» Thermal effective and interface resistance
» Compact all-in-one system
Feasible Samples
» Thermal interface
materials
» Die attach materials
» Underfill materials
» Molding compound
» Substrates
» Foils
» Multilayer samples
test chip for application-related studies
Unique Selling Points of TIMA®
» Conformity to standard ASTM D5470 for TIM characterization
» Characterization under application-related or any other customer-specific conditions
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Tobias von Essen
Heater
Cooler
sample
T1
T2
T3
T4
T5
T6
Up
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ce b
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TTV
Cooler
sample
T4
T5
T6
Lo
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T0
Measurement between
silicon and metal surfaces• real application case for TIM1
• Using In-house developed
Thermotest module with
integrated heater and
temperature sensors
Application of different
metals as contacting surface
material
In-situ investigation of aging
behavior of TIM
Preparation of cured samples
in desired bond line thickness
Application-specific definition
of contacting surface finishing
F F
Thermal characterization of thermal grease
Highly filled polymer
» Eff. thermal resistance over bond line thickness
→ Bulk thermal conductivity and contact resistance
» Thickness range 25 to 200 µm
» 60°C sample temperature
Tobias von Essen
27 June 2019
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0 50 100 150 200
Rth
[cm
²K/W
]
Thickness [µm]
R² = 0.99902
λbulk = ± 0.11 W/mK; Interface resistance Rth,0=5.05 0.015 ± 0.002 cm²K/W
Thermal characterization of gap filler
Tobias von Essen
27 June 2019
non-cured
cured for 1 hour at 150°C
0,0
0,5
1,0
1,5
2,0
2,5
0 200 400 600 800 1000
Rth
[K/W
]
BLT [µm]
data points
linear fit
R² = 0.99991
λbulk = 2.97 ± 0.08 W/mK
Rth,0 = 0.14 ± 0.01 K/W
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
0 100 200 300 400 500 600 700
Rth
[K
/W]
BLT [µm]
data points
linear fit
R² = 0.99981
λbulk = 3.03 ± 0.09 W/mK
Rth,0 = 0.12 ± 0.01 K/WHeater
Cooler
sample
T1
T2
T3
T4
T5
T6
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ow
Gap filler Assembly tool
TIM under test in TIMA
TIM layer after test
Some Gap Filler measured at cured and non-cured state
Thickness [µm]
Thickness [µm]
» Mechanical or thermal cycling
» Combined loading
» In-situ measurement of BLT and pressure
» In-situ measurement of thermal resistance
» Computer-controlled long term testing
Ageing investigations with TIMA®
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Tobias von Essen
2
2,5
3
3,5
4
4,5
5
5,5
6
6,5
7
0 500 1000
therm
al re
sist
an
ce [
K/W
]
cycle count
Step 1
Step 2
RB
expansion
compression
⇅ RB
RB
⇅ RB
Step 1 Step 2
T
timeΔporΔd
Mechanical loading
Thermal loading
Co
mb
ined
load
ing
TIM
RB
expansion
compression
⇅ RB
TIM
RB
TIM
RB
⇅ RB
Exa
mp
le Two-component gap filler» initial thickness 300 µm
» 10 % expansion at 80°C
» +90% Rth increase after 1000 cycles
https://linustechtips.com
aged thermal grease layer
LaTIMA® Lateral Thermal Interface Materials Analyzer
» In-plane thermal conductivity measurement of high thermally conductive materials
27 June 2019
Tobias von Essen
sample
sample
sampleQ
TRth
=
Cooler
T4
T5
T6
Heater
T3
T2
T1
1stre
fere
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bo
dy
2n
dre
fere
nce
bo
dy
IR
ΔT
Heat flow Q
L
Sample
Heater
Cooler
sample
T1
T2
T3
T4
T5
T6
Up
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refe
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ce b
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wer
refe
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ce b
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transform
LaTIMA®Lateral Thermal Interface Material Analyzer
27 June 2019
Tobias von Essen
Material Characterization of Highly Conductive Materials
Feasible Samples
» Metals & alloys
» Substrates & ceramics
» Solder
» Sintered material
» Semiconductors
Material Parameters
» In-plane thermal conductivity
» Thermal diffusivity
(available with TIMA™wave add-on module)
Processing-Structure-Property Correlations of Sintered Silver
27 June 2019
sample, L=20 mm,
W=5 mm, T=150
µm
Samples
preparation,
variation of sinter
parameters
Structure analysis by FIB and SEM
Measurement of thermal
conductivity by LaTIMA
Thermal conductivities as
function of sintering parameters
Thermal conductivity as function of porosity
Tobias von Essen
TIMA®wave
Measurement of in-plane thermal diffusivity of substrate (e.g. AlN, Al2O3, Si3N4 etc.), die attach (e.g. solder, sinter Ag, sinter Cu etc.), metals and alloys
27 June 2019
I
R
Lock-in
processing
Amplitude
and phase
informatio
n𝑇 𝑡 = 𝐴 ∙ sin(𝜔𝑡)
Laser
driver
Power
supply
Sample
Temperature stage
Thermal isolating
Induction
heater
IR cam
Sample
Laser
Inducti
on
heater
x
Amplitude Image
Phase Image
𝑘𝑎𝑚𝑝
𝑘𝑝ℎ𝑎
𝑘𝑎𝑚𝑝
𝑘𝑝ℎ𝑎
Am
pli
tud
e
x
Ph
ase
Tobias von Essen
Thermal diffusivity results
» metals and metals alloys
» ceramics
» semiconductors
27 June 2019
5 mm
Cu
Cu
Zn
Ag
Al
Si Si Si Si
CeramicsMetalsSemiconductors
Thermal diffusivity of different materials at room temperaturesThermal diffusivity of low and high doped Si at different
temperatures
Tobias von Essen
Thermal characterization of carbon fiber reinforced polymer
Carbon fiber composite panel
Material
T700 Toray unidirectional carbon fiber, EPIKOTE Resin MGS
L135, EPIKURE Curing Agent MGS H137; hand layup with
vacuum bagging at 100%, 50% and 0% of full vacuum to
vary void content [1]
[1] I. Hakim, D. May, M. Abo Ras, N. Meyendorf, S. Donaldson, Quantifying voids effecting delamination in
carbon/epoxy composites: static and fatigue fracture behaviour, Proc.SPIE 9806, 9806H1 (2016).
Vacuum bagging
Sample cutting
2 mm0.2 mm
InitialAfter preparation
Tobias von Essen
27 June 2019
Characterization with LaTIMA® 24
Dan R. Wargulski
30. Jan. 2019
Cooler
T4
T5
T6
Heater
T3
T2
T1
1stre
fere
nce
bo
dy
2n
dre
fere
nce
bo
dy
IR
ΔT
Heat flow Q
L
Sample
Sample Thermal
conductivity
[W/(m∙K)]
Error
[W/(m∙K)]
CFRP_x 6.2 ±1.5
CFRP_y 4.5 ±1.5
x
zy
sample
Linear Fit of Rth over BLT
TIMA® ASTM D 5470 Conformity
Tobias von Essen
27 June 2019
𝑅𝑡ℎ𝑒𝑓𝑓 =Δ𝑇
𝑄
𝑅𝑡ℎ𝑒𝑓𝑓 = 𝑅𝑡ℎ𝑏𝑢𝑙𝑘 + 𝑅𝑡ℎ0
0
1RthBLT
ARth
bulk
eff +
=
Rth
BLT
bulk
1~
The linear fit over BLT bears information about bulk thermal
conductivity and the effective thermal interface resistance
𝑄 =∆𝑇𝑅𝐵
𝑙𝑅𝐵𝐴𝑅𝐵 𝜆𝑅𝐵
Heater
Cooler
sample
T1
T2
T3
T4
T5
T6
Up
per
refe
ren
ce b
od
yLo
wer
refe
ren
ce b
od
y
heat
flo
w
(\textit{$\Delta$T}) T3
T4
Rth0.1
Rthbulk
Rth0.2
Thermal characterization of substrates
High surface roughness → high interface resistance
→ interface resistance dominates
Use of thermal interface material or liquid metal in contact
areas
→ elimination of the interface resistance
Heat sink
TTC
refe
rence
sock
et
T3
T2
T1
DUT
Liquid metal
20 40 60 80 100
12
14
16
18
20
22
24
26
28
30
Rth
[m
m²K
/W]
BLT [µm]
Km
W
sbulk ==
2,13,8
1
Hot plate
Coldplate
Substrate
Rth0,1
Rth0,2
RthsubRtheff
voids
Hot plate
Coldplate
Substrate
Rth0,1 ~0
Rth0,2 ~0
RthsubRtheff
Liquid metal
Liquid metal
(61.0Ga/25.0In/13.0Sn/1.0Zn)
Heater
Cooler
sample
T1
T2
T3
T4
T5
T6
Up
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refe
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refe
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ce b
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Liquid metal
Tobias von Essen
27 June 2019
Carbon fiber reinforced polymer
50 %Vacuum 100
% 0 %
» Thermal conductivity increases as the vacuum level increases, due to
decreasing void content
𝜆 = 0.75 W/mK 𝜆 = 0.69 W/mK 𝜆 = 0.64 W/mK
Direction Bulk thermal conductivity
W/mK for vacuum 100%
Longitudinal (fiber direction) > 4.5 ± 0.02
Transverse (90o to fiber
direction)
0.80 ± 0.02
Cross-plane 0.75 ± 0.02
Tobias von Essen
27 June 2019
IR-thermography for void detection
27 June 2019
Tobias von Essen
50% vacuum level
PPT-amplitude image 50%_#26_T
PPT-phase image 50%_#26_T
PT- image 50%_#26_T
PPT-amplitude image 100%_#16_B
PPT-phase image 100%_#16_B
PT- image 100%_#16_B
100% vacuum level
Vacuum Level Void volume fraction
0 % 3.7 %
50 % 3.1 %
100 % 1.3 %
» Defects visible in amplitude and phase images.
27 June 2019
Tobias von Essen
Basic principle of thermal imaging based FA
cam
good
bad
Lab scale equipment
27 June 2019
Tobias von Essen
IR
camera
funnel
attachment
Fresnel lens
attachment
Trigger and
synchronization unit
molded APC
samples
DEMO TRT#1, delamination die attach
DEMO APC#1, void in molded QFN
→Successful detection of failure: delam. and void
Comparison high-end and low-cost Camera
SAM PIRT (high-end) PIRT (low-budget)
X1_1_1
Tobias von Essen
→Flash IR pulsed experiment on DEMO APC#1 also successfully
→Low-cost provide good results at much lower form factor and lower costs
→Enables cost efficient FA systems
27 June 2019
INFAS - Modular building kit for in-line quality assessment
27 June 2019
Tobias von Essen
Range of detectable defects
🞂 Voids and material inclusions
🞂 Delamination
🞂 Cracks and lift-offs
🞂 Compact form factor
🞂 Contact-less measurement
🞂 Results within seconds
🞂 Complete solution in hard- and software
🞂 Open and flexible system design
🞂 Adaptable to special customer needs
Unique selling points
Voids in solder die attach layer
Voids in carbon fiber reinforced
polymerVoids in molding compound
Delamination in sintered power
module
IRca
m
conveyor belt
Sinter layer
delamination
Void in mold
compound
INFAS - Modular building kit for in-line quality assessment
27 June 2019
Tobias von Essen
Excitation sources Thermal imaging systems
€€
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Co
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en
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Pro
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lin
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FAS
Computation
exc
ita
tio
n
resp
onse
Failure analysis hardware | custom fusion of
excitation and imaging hardware
Analysis software
image processing,
defect localization
and decision making
based on
machine learning
Conclusion
» Reliability is greatly about thermal performance
» It begins with the ingredients, it ends with the process
» Different material requires different approaches
» Flaws and defects may be anywhere
» We offer full-range support for thermal questions
27 June 2019
Tobias von Essen
Thanks for Your attention
nanotest.eu
27 June 2019
Tobias von Essen