Semicon Japan 2013 press

Time-Resolved Thermoreflectance Imaging
for Thermal Testing and Analysis
Dr. Mo Shakouri
Chairman
Microsanj, LLC., Silicon Valley USA
[email protected]
Applications
APPLICATIONS FOR MICROSANJ NANOTHERM-SERIES THERMOREFLECTANCE THERMAL IMAGING SYSTEMS
Thermal
Characterization &
Thermal Profiling
Time-Dependent
Thermal Analysis
0.5ms
0.7ms
0.9ms
0.95ms
1.0ms
3.0ms
Flip Chip Thermal
Analysis
Hot Spot Detection &
Failure Analysis
500 nm HotSpot
·
·
·
·
Key Benefits
2D and 3D images
Spatial resolution to 300 nm
Time resolution to 800 ps
Temperature resolution to
0.5 °C
·
·
Key Benefits
Characterize high speed
logic circuits
Transient analysis in ns to ps
range
·
·
·
·
Key Benefits
In SITU thru-the-substrate
imaging
Heat sinking integrity
Thermal time delay pinpoints thermal source
link emission & thermal
images
SEMICON JAPAN 2013 - MICROSANJ
Key Benefits
Find & analyze:
· Short circuits
· Oxide defects
· Junction defects
· High resistance vias
· Processing defects
· etc
Outline
1.
2.
3.
4.
5.
6.
Motivation
Instrumentation
Lock-in mechanism
Imaging through silicon (near IR)
Diffusion length
Examples
Small hotspot / Logic circuitry / Emission /
Depth in metal layers
7. Summary
SEMICON JAPAN 2013 - MICROSANJ
Challenges on thermal
characterization
General challenges for electronics devices
• Small features: 10s nm – 100s microns – difficult to contact
• High speed response due to the small thermal mass
• Highly non-uniform
Additional challenges for photonics and power devices
• Light emission (photonics)
• High heat density
• Heat sinks requirement (power devices)
SEMICON JAPAN 2013 - MICROSANJ
Thermoreflectance imaging setup
Console box
Microscope setup
CCD
Sig. gen.
Temp. contl.
LED
Control box.
Objective lens
DUT
SEMICON JAPAN 2013 - MICROSANJ
How it works - thermoreflectance
LED driver
Power
LED
GP-IB
GP-IB
PC
Computer
Detector
Detector
CCD, InGaAs
InGaAs
CCD,
Light
I
R1
Beam
splitter
Pulse generator & power amp
Microscope
Objective
Device
Device
Pulse generator
& power amp
 R  1 R 

 T  T
R  R T 
Thermal bed
bed
Thermal
System diagram
Thermoreflectance
coefficient
SEMICON JAPAN 2013 - MICROSANJ
Lock-in signals
Timing chart
4ms @ 25% Duty Cycle
Device
Excitation
1ms
CCD
exposure
33ms @ 30Hz
LED
pulse
t0
100ms
t0
delay
t1
t1
Temperature
Acquisition timing (shifting by cycle)
Temperature data point along the bias cycle
SEMICON JAPAN 2013 - MICROSANJ
Through silicon and emission
InGaAs CCD
Top view
1300 nm
LED
Objective
Substrate
Flip Chip DUT
% Transmittance
Transmittance vs Wavelength, Si
(Image from http://www.janis.com)
Bottom view
resolution
1.0
10.0
Wavelength, mm
SEMICON JAPAN 2013 - MICROSANJ
Defects and signature of potential failure
Emission – sign of high density of electron collisions
Thermal hotspot – location of potential long-term reliability
Thermal foot print  irregular local energy spot
k  AT / Tref  e  Ea /  RT 
n
Arrhenius's law
Transient irregular timing - potential of logic/operation failure
Near Infrared (NIR) wavelength provide a capability of both
thermal signal and emission simultaneously.
LED options: 1050, 1200, 1300, and 1500 nm
SEMICON JAPAN 2013 - MICROSANJ
Resolution and sensitivity
Temperature
SNR  n
Spatial resolution
d

2n sin  
n : number of averaging
due to the weak signal (Cth ~ 10-4 order)
Visible wavelengths, d ≈ 250-300 nm
NIR d ≈ 500 nm
d ≈ /2
Time resolution
t 
0.02

x2
As scaling smaller, time resolution must
be smaller due to thermal diffusion.
t : 100ns for our setup.
(for 1% error in
temperature)
Emission
InGaAs uncooled camera effective
sensitivity of one pixel for emission
~ 30 mW/mm2
SEMICON JAPAN 2013 - MICROSANJ
Examples - Small hotspot
a)
1.4
onMOSFET
MOSFET
1.4mm
mm gate
gate on
b)
Temperature (a.u.)
(a.u.)
Temperature
70
60
60
50
50
40
40
40
30
30
20
20
10
10
00
00
22
66
88
Distance(mm)
(μm)
Distance
44
SEMICON JAPAN 2013 - MICROSANJ
10
10
12
12
Transient Behavior of IC Latch-Up
Movie1
- Potential timing failure 0.5 ms
75
0.7 ms
0.9 ms
1.0 ms
3.0 ms
37.5
0
Y
X
The latch-up location is circled in yellow
SEMICON JAPAN 2013 - MICROSANJ
Thermal and emission overlay images
5x
Thermal signals
Through silicon
substrate, 450 mm thick.
LED  = 1300nm and
InGaAs camera (640 x 512)
50x
Emission signals
44 mW
25µm
SEMICON JAPAN 2013 - MICROSANJ
Diffusion time/depth estimations
m: depth of heat source
: thermal diffusivity [m2/s]
m  2 t
t: time to reach observing surface
m2
t
 3125 m 2 (for Si)
4
Diffusion time estimations
SiO2
Si
Cu
Al
Ag
Au
Thermal diffusivity: α (m²/s) 8.30E-07 8.80E-05 1.11E-04 8.42E-05 1.55E-04 1.27E-04
thickness (µm)
diffusion time (µs)
1
0.301
0.003
0.002
0.003
0.002
0.002
5
7.53
0.07
0.06
0.07
0.040
0.05
10
30.1
0.3
0.2
0.3
0.162
0.2
25
188
1.8
1.4
1.9
1.011
1.2
50
753
7.1
5.6
7.4
4.045
4.9
100
3,012
28.4
22.5
29.7 16.181
19.7
SEMICON JAPAN 2013 - MICROSANJ
Examples - Through silicon, deep
under the 6th metal layer
Thermal imaging
Flip chip side view
M1
M7
2.0 msec
0.97V, ~12mA, ~12mW 20% duty cycle
10 minutes of averaging (repeating)
SEMICON JAPAN 2013 - MICROSANJ
Movie2
Time delay to reach to the surface
Normalized Temperature
Precise time resolution is a key to find the response.
1.2
1
0.8
0.6
~75 µs
delay
0.4
PolyResistor
resistor (top layer)
Poly
Short
(under
6 layers)
140
Ohm
Short
0.2
0
0
200
Time (µs)
400
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600
Microsanj, a technology leader in
thermal imaging field
 Founded by a team of PhDs from CalTech, Stanford, and UCSC in 2007
 More than 30 papers published to date
Major Customers
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Collaborative Research Activities
Chip Test Solutions
Design Engineering Inc. (DEI)
Infinera
Instituto de Microelectronica de
Barcelona (CSIC)
Intel Corporation
Nanyang Technological University
Purdue University
Raytheon
Silicon Image
University of California Santa Barbara
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A*Star Singapore
Altera Corporation
Birck Nanotechnology Center at Purdue
University
Nvidia
Philips Electronics
Qualcomm
Silicon Frontline
Si-Ware Systems
ST Microelectronics
Texas Instruments (National
Semiconductor)
University of California at Santa Cruz
SEMICON JAPAN 2013 - MICROSANJ
Summary
High speed time-resolved thermoreflectance imaging is
introduced.
NIR illumination provides a through Si and electron emission
Lock-in thermography and EMMI are compared.
Examples demonstrated:
Hotspots ~ 1mm, emission and thermal overlay,
and a hotspot underneath 6 metal layers
SEMICON JAPAN 2013 - MICROSANJ
Microsanj社の開発した熱画像解析装置、Nanothermシリーズは、これまでのIRによるサーモグラ
フィー装置とは全く異なった温度測定技術を用いたシステムです。測定物のIR放射を測定するのでは
なく、測定物に非常に短時間の光を照射し、その反射光を計測することにより温度分布を測定するた
め、測定物に全く影響を与えること無く、IRでは難しかった広い温度範囲を非接触にて測定することが
可能となりました。測定は金属を含むあらゆるものが可能で、測定物を熱したり、表面に特別な処理を
行う必要が有りません。また、薄いシリコン基板は光を透過することから、flip-chip等の、シリコン基板
上の半導体の熱画像を裏面から観測することが可能です。また、Nanothermシステムの最大の特徴
として、オプションにてバイアス電源と信号源を追加することにより、熱画像の過渡特性を、最速では
0.8nsec間隔で測定することができます。Nanothermシステムにより、温度上昇、熱集中の状況をリア
ルタイムに観察することで、半導体そのものや半導体回路の最適な熱設計を行うこと、また故障解析、
不良解析を行うことが可能です。測定物の大きさは最小300nm、温度分解能は最小0.2℃、測定温度
範囲-265～500℃に対応します。
ATN Japan
1-35-16 Nakagawa-Chuo
Tsuzuki, Yokohama, Kanagawa, 224-0003 JAPAN
Website: www.atnjapan.com
E-mail: [email protected]
SEMICON JAPAN 2013 - MICROSANJ
Transient thermal/emission imaging
Resolution
x(mm)
T (K)
Imagt (sec) ing?
m Thermocouple
50
0.01
0.1-10
No
Contact method
IR Thermography
3-10
0.02-1
1m
Yes
Emissivity dependent
Lock-in Thermog.
3-10
1m
NA
Yes
Need cycling
Method
Notes
Liquid Crystal
Thermography
2-5
0.5
100
Yes
Only near phase
transition (aging
issues)
Thermoreflectance
0.30.5
0.08
800p0.1m
Yes
Need cycling
Optical scanning
Interferometry
0.5
100m
6n0.1m
Scan
Indirect measurement
(expansion)
Micro Raman
0.5
1
10n
Scan
3D T-distribution
Scanning thermal
microscopy (SThM)
0.05
0.1
10100m
Scan
Contact method
surface morphology
Emission
Microscopy (EMMI)
0.25
-
Op
lock-in
Yes
Emitted Photon
density
s.im.lens
SEMICON JAPAN 2013 - MICROSANJ

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