High Temperature Wafer Probing of Power Devices
Masatomo TakahashiACCRETECH
Georg FranzT.I.P.S Messtechnik GmbH
OverviewGeorg Franz
1. Introduction to Power Devices2. Testing Requirements3. Probe Card SolutionMasatomo Takahashi
4. Prober Chuck Improvement5. Experiment: Chuck Thermal Stability6. Conclusion, Follow-On Work
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Power Devices - Applications• Power supplies• Air Condition• Electric Vehicles• Industrial Automation• Trains, Wind Turbines,
Photovoltaic• Power Transmission
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image source: Tsunenobu Kimoto, Japanese Journal of Applied Physics 54, 040103, 2015
Power Devices - Applications in HEV/EV• Rectifiers
Grid AC -> DC charger
• InvertersDC 800V -> AC motor winding
• ConvertersDC 24V -> HV busGenerator -> HV bus
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image source: ST Microelectronics
Power Devices - Types• Si-based devices:– PIN, SBD– IGBT– GTO
• SiC/GaN-based devices:– MOSFET– BJT– JFET
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image source: Littelfuse
image source: ABB
PowerDevices – Wide Band Gap• Silicon Carbide• Gallium Nitride
• Smaller Devices• Higher Efficiency• Less Cooling Effort
• Higher Operating Voltage!• Higher Operating Temperature!
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image source: ST Microelectronics
Test Requirements - Overview• Reverse Voltage (Breakdown Voltage)
-> Up to several kV
• Reverse Voltage (Leakage Current)• Forward Current (On-state resistance)
-> Up to several kA
• UIS – Unclamped Inductive Switching (max power dissipation)
-> Up to several kA / kV
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image source: Wolfspeed,
SiC-MOSFET
image source: ABB, 6.5kV-
600A Si-IGBT
Wafer Test• Current test applications:
– Bare Die– Engineering/Characterization
• Potential test applications:– Tri-Temp Automotive– Move from package to wafer test– Reduce test cost by 50%
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$
High Voltage Wafer Test• Vertical Device• Wafer Bulk on HV• Flash-over risk to
dicing frame!
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C
E G E G
Floating (HV) GND
HV
6 kVDUT2 DUT1
Example: Vertical Device, IGBT (Insulated Gate Bipolar Transistor)
Flash-Over SuppressionApproaches:
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Liquid Inert Gas high breakdown
strength possible
immersion necessary
not useful for wafer test
flushing prober at ambient pressure
pure SF : 3-fold breakdown strengthof ambient air
high cost, greenhouse gas
Pressure linear increase of
breakdown voltage with pressure
works with any gas
compressed air
Flash-Over Suppression - Solution• Air under higher pressure (Paschen)
– whole prober under pressure– whole wafer under pressure– chip-scale chamber– contactless chip-scale chamber
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C
E G E G
Floating (HV) GND
HV
6 kVDUT2 DUT1
Contactless chip scale pressure chamber
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Contactless Seal Operation
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HV-HT Probe Card• Hot compressed
air supply• Dual hot-cold
air streamto protect probe card
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hot compressed air inlet
hot chuck
probe needles
wafer
pressure chamber
gap
PCB moveable Lupo seal ring
cold air flow
hot airflow
150°C
150°C
25°C
High Voltage – High Temperature• Hot air has lower density
-> reduced breakdown strength • Pressure must be increased
to get same breakdown strength• At 125°C -> 36% higher
pressure needed!
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50%
60%
70%
80%
90%
100%
25 75 125 175 225Temperature [°C]
Relative Breakdown Strength
HV-HT Probe Card• production wafer sort• hot wafer chuck 150°C• hot compressed air 150°C• non-contact Lupo seal
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High Temperature Pressurized Air Supply• Electrical heater• Heats cold compressed air to 150°C• closed-loop temperature control• temperature sensor in probe card• fast settling, stable operation• integrated air cooling for probe card
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High temperature testConventional high temperature test condition.
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Chuck Top
Wafer
Blow ambient air
Heater & Temp. Sensor(High temp.)
Probe Card
Chuck (wafer) temperature goes down !
Current issue and improvements
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105
110
115
120
125
130
135
140
145
150
155
0 500 1000 1500 2000 2500 3000 3500 4000
Chuc
k te
mp(
deg)
Time(sec)
Condition: set temp.=150℃/0.5MPa/Die size=2.5㎜/Test time=1000msAir blow start
Probing
Waiting temp. stability
Stronger heater with some sensors
Original heater witha sensor
Original heater with some sensors
High temperature test with Hot air controller
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Prober:UF2000
Hot air controller: LMH150
Probe card: ACTP001-HT
High temperature test enhancementBlow hot air into probe card instead ambient air.
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Chuck Top
Wafer
Blow hot air
Heater & Temp. Sensor(High temp.)
Probe Card
better Temperaturestability
Experiments• Temp. test-1 :
– Chuck temperature stability time after hot air blow start.
• Temp. test-2 : – Chuck temperature variation during probing.
by changing compressed air pressure, Die size, Testing time, etc.
• Flash-over spark test : – With compressed hot air & T.I.P.S. HV demo wafer.
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Temp. test-1– Chuck temperature stability time after air blow start.– Result: Return to chuck set temperature (150℃) within 3min using LMH150
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135
137
139
141
143
145
147
149
151
153
155
0 200 400 600 800 1000 1200Time(sec)
Chuck temperature after air blow
A:High temp air blow Room temp air brow
Air blow start(0.5Mpa)
Approx. 3minStandard probe card (ACTP001) with room temp. air blow.
ACTP001-HT with hot air blow.
Temp. test-2– Chuck temp. during probing with different conditions
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Chuck Temp.(℃)
Pressure(MPa) Chip size(㎜)
Test time(msec)
100 0.3 5.0 300
100 0.5 5.0 1000
150 0.3 5.0 300
150 0.5 5.0 300
150 0.5 5.0 1000
150 0.5 2.5 1000
Temp. test-2– Chuck temp. variation during probing-1– Condition: Set temp.=100℃/0.3MPa/Die size=5㎜/Test time=300ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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85
87
89
91
93
95
97
99
101
103
105
0 200 400 600 800 1000 1200 1400 1600Time(sec)
Chuck temperature during probing
Room temp air brow High temp air blow
Air blow start
Waiting temp. stability Probing
85
87
89
91
93
95
97
99
101
103
105
0 500 1000 1500 2000 2500Tim(sec)
Chuck temperature during probing
Room temp air blow High temp air blow
Temp. test-2– Chuck temp. variation during probing-2– Condition: Set temp.=100℃/0.5MPa/Die size=5㎜/Test time=1000ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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Waiting temp. stability Probing
Air blow start
Temp. test-2– Chuck temp. variation during probing-3– Condition: Set temp.=150℃/0.3MPa/Die size=5㎜/Test time=300ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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135
137
139
141
143
145
147
149
151
153
155
0 200 400 600 800 1000 1200 1400 1600Time(sec)
Chuck temperature during probing
Room temp air blow High temp air blow
Air blow start
Waiting temp. stability Probing
Temp. test-2– Chuck temp. variation during probing-4– Condition: Set temp.=150℃/0.5MPa/Die size=5㎜/Test time=300ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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135
137
139
141
143
145
147
149
151
153
155
0 200 400 600 800 1000 1200 1400 1600
Time(sec)
Chuck temperature during probing
Room temp air blow High temp air blow
Air blow start
Waiting temp. stability Probing
Temp. test-2– Chuck temp. variation during probing-5– Condition: Set temp.=150℃/0.5MPa/Die size=5㎜/Test time=1000ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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135
137
139
141
143
145
147
149
151
153
155
0 500 1000 1500 2000 2500
Chuck temperature during probing
Room temp air blow High temp air blow
Air blow start
Waiting temp. stability Probing
Temp. test-2– Chuck temp. variation during probing-6– Condition: Set temp.=150℃/0.5MPa/Die size=2.5㎜/Test time=1000ms– Result: Chuck temp. is very stable. (Set temp. ±1℃ during probing)
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135
137
139
141
143
145
147
149
151
153
155
0 1000 2000 3000 4000 5000 6000 7000
Chuck temperature during probing
Room temp air blow High tep air blow
Probing
Waiting temp stability
Air blow start
Temp. test-2– Chuck temp. during probing – Test result summary
• Summary:– When using standard probe card with ambient air at 150 ℃, the variation of chuck temp. is +5 to -14℃
max. It is mostly related to air pressure value, not to test time and die size. If using LMH150 with ACTP001-HC, the variation is +/-1℃ under all above conditions.
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Chuck Temp.(℃)
Pressure(Mpa) Chip size(㎜)
Test time(ms) Result
100 0.3 5.0 300 +/-1℃100 0.5 5.0 1000 +/-1℃150 0.3 5.0 300 +/-1℃150 0.5 5.0 300 +/-1℃150 0.5 5.0 1000 +/-1℃150 0.5 2.5 1000 +/-1℃
Flash-Over Spark TestHigh voltage at 100°C
If the test area temp. (inside of Lupo-Ring) is going up, the flash-over voltage is dropped. In case of ACTP001 with ambient air even if chuck temp. is 100℃, the test area temp. must be lower. So the flash-over voltage is just a little bit dropped.
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1
1,5
2
2,5
3
3,5
0 0,1 0,2 0,3 0,4 0,5 0,6
Flas
h-ov
er V
olta
ge (k
V)
Compress Air (MPa)
Flash-over voltage comparison
Drop flash-over voltage approx. 25 %.
Chuck=AmbientCard=ACTP001Air=Ambient
Chuck=100℃Card=ACTP001Air=Ambient
Chuck=100℃Card=ACTP001-HTAir=100℃
Graph1
0.30.30.3
0.40.40.4
0.50.50.5
ambient
100℃
100℃(高温カード)
Compress Air (MPa)
Flash-over Voltage (kV)
Flash-over voltage comparison
2.56
2.44
1.92
2.96
2.82
2.16
3.32
3
2.34
Sheet1
再現が少し悪い サイゲンスコワル
120-137121-137122-137123-137124-137120-137121-137122-137123-137124-137125-137126-137127-137128-137129-137
201808151回目 カイメ0.53.43.333.13.10.222.42.12.12.12.22.32.62.62.7
0.43.22.82.933.10.32.72.42.52.22.72.32.52.52.12.1
0.32.52.82.22.42.70.42.832.833.12.62.832.82.6
0.22.12.42.22.32.40.53.53.43.13.33.23.13.13.33.13
2回目 カイメ0.53.23.33.13.22.90.22.12.42.322.52.222.222
0.42.82.92.92.63.10.32.22.42.72.62.62.42.42.42.32.7
0.32.32.32.32.72.70.43.23.12.92.92.62.92.832.62.9
0.22.22.322.42.20.53.43.33.33.23.23.33.13.33.33.3
500uA
2.2
ウェーハ再クリーニング サイ2.5
20180816120-137121-137122-137123-137124-1373.2
1回目 カイメ222.52.12.22.33.4
0.32.52.62.32.32.7
0.432.92.82.92.6
0.53.33.33.23.13.2
2回目 カイメ0.22.12.52.12.22.4
0.32.52.82.52.62.6
0.42.63.232.82.9
0.53.53.43.23.23.2
20180816120-137121-137122-137123-137124-137AVE
28℃1回目 カイメ0.32.42.62.72.42.72.56
0.42.82.93.12.93.12.96
0.53.43.53.13.13.53.32
2回目 カイメ0.32.72.92.62.42.5
0.42.932.83.13
0.53.43.43.43.43.5
20180816120-137121-137122-137123-137124-137
100℃1回目 カイメ0.32.32.72.12.62.52.44
0.43.12.82.82.92.52.82
0.53.2332.92.93
2回目 カイメ0.3
0.4
0.5
20180817120-137121-137122-137123-137124-137
100℃1回目 カイメ0.32.52.32.12.62.3
42%0.42.92.92.72.82.5
0.53.33333.1
2回目 カイメ0.32.12.42.52.32.6
0.42.832.52.52.9
0.53.43.12.933
20180817120-137121-137122-137123-137124-137
150℃1回目 カイメ0.3
42%0.4
0.5
2回目 カイメ0.3
0.4
0.5
20180817120-137121-137122-137123-137124-137
室温(再) シツオンサイ1回目 カイメ0.32.62.72.62.52.72.62
劣化確認 レッカカクニン0.42.92.62.92.932.86
40%0.53.43.63.13.23.43.34
2回目 カイメ0.32.52.52.62.72.8
0.4333.13.23.3
0.53.53.53.43.43.7
高温カード コウオン
20180820120-137121-137122-137123-137124-137
100℃1回目 カイメ0.321.91.91.91.91.92
0.42.222.12.22.32.16
0.52.32.32.42.32.42.34
2回目 カイメ0.3221.91.91.9
0.42.32.12.22.22.3
0.52.72.42.52.42.5
温度上昇後、厚さ合わせ出来ず。セラミックの反り?
Sheet1
室温(従来カード)
100℃(従来カード)
100℃(高温カード)
気圧(MPa)
スパーク電圧(KV)
高温でのスパーク電圧比較
Sheet2
Sheet3
Flash-Over Spark TestHigh voltage at 100°C
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Test wafer Check flash-over by camera & monitor.
Conclusion & Follow-On WorkConclusion
– Proven Solution for High-Temperature High- Voltage Wafer Test– Achieved the improvement by chuck design change and using hot air
controller.
Follow-On Work– More field test– Integrate hot air controller into prober– Extend Temperature Range
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Thank you for your attention!
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For questions, please contact:
Masatomo Takahashi
ACCRETECH
+81 426 42 0381
For questions, please contact:
Georg FRANZ
T.I.P.S. Messtechnik GmbH
+43 4242 319 720 19
High Temperature Wafer Probing of Power DevicesOverviewPower Devices - ApplicationsPower Devices - Applications in HEV/EVPower Devices - TypesPowerDevices – Wide Band GapTest Requirements - OverviewWafer TestHigh Voltage Wafer TestFlash-Over SuppressionFlash-Over Suppression - SolutionContactless chip scale pressure chamberContactless Seal OperationHV-HT Probe CardHigh Voltage – High TemperatureHV-HT Probe CardHigh Temperature Pressurized Air SupplyHigh temperature testCurrent issue and improvementsHigh temperature test with Hot air controllerHigh temperature test enhancementExperimentsTemp. test-1Temp. test-2Temp. test-2Temp. test-2Temp. test-2Temp. test-2Temp. test-2Temp. test-2Temp. test-2Flash-Over Spark TestFlash-Over Spark TestConclusion & Follow-On WorkThank you for your attention!