advances in vertical probe material for 200 wafer test applications · 2019. 6. 16. · advances in...
TRANSCRIPT
Advances in Vertical Probe Materialfor 200℃ Wafer Test Applications
Author & presenter, Mitsuhiro MoriyamaCo-Author, Stephane Denarnaud
Co-Author, Hiroyuki IchiwaraSV TCL KK, JAPAN
introduction• Application for automobile require test temperatures of 180℃ and
above.• Our B2 vertical standard cards can address the pitch and pin counts for
such devices and has been used up to 150℃
2
B2 probe card SoC / Automotive / 150℃ Fine pitch
Agenda• Current B2 probe at 200℃.• Development of a new material.
– Discoloration– Wire breakage– Wire softening
• Probe material evaluation results.– Head design– General characterization– Durability test
3
First test at 200℃
Probe tip discoloration.The darker tip results in prober alignment errors!
4
Wire sample Probe tip as viewed on the prober
Initial
Afterheating
STD
Other common probe materials
5
We considered most common materials:
STD AgPdCu Rh Ir W
Chemical Discolor NG! OK OK OK OK
MechanicalStiffness OK OK OK NG! NG!
Drawing thin wire OK OK OK NG! OK
ElectricalCCC OK NG! OK OK OK
Cres at high temp OK OK NG! not clear NG!
No suitable material is readily available, we will develop our own!
Process and effective factor
6
1. Alloy Composition
3. Drawing to wirewith some heat treatment
2. Mixing and MeltingCasting to ingot
4. Making probe at Φ35um
Discoloration
Resistivity
Stiffness
Hardness
Strength
Improvement for discoloration at 200℃
7
STDComposition changes
Test1 Test2 Test3 Test4 Test5
We after several composition changes we resolved the discoloration problem
AcceptableAcceptableAcceptable
Process and effective factor
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1. Alloy Composition
3. Drawing to wirewith some heat treatment
2. Mixing and MeltingCasting to ingot
4. Making probe at Φ35um
Impurity
Segregation
Brittleness
Internal defects
Broken wire
Broken wire in drawing process
9
Impurity defect Wire drawing Probe processing
After several attempts and process improvement breaking wire issues were solved
Process and effective factor
10
1. Composition and additives
3. Drawing to wirewith some heat treats
2. Mixing and MeltingCasting to ingot
4. Making probe at Φ35um
softening
Bending
Heat resistance
5. Probe Evaluation
Softening and Bending under heat • Probed remained bent after OD and high temp.• Hardness changed after prolonged exposure.
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Bending
0 2 4 6 8 10 12
hard
ness
time(hour)
Vickers hardness degradation
Recrystallization
12
• Recrystallization occurs way below the melting point, typically for pure metals at around 30 to 50% of the melting temperature.
• Coarsened crystals will results in a decrease of hardness and strength.
300℃30分加熱後
After 0.5h at 300℃BeforeTest 4
Summary the alloys tested
13
Wire evaluation Probe evaluation
Alloy Discolor Broken in wire work
Softening under heat
Bending under heat
Test 1 NG - - -Test 2 NG - - -Test 3 OK NG - -Test 4 OK OK NG NG Test 5 OK NG - -
EH OK OK OK OK
Finally we get results!
Evaluation of EH(Extremely High Temp)
probe material
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LGP
UGP
Wafer
Specification of evaluation probe head
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Probe
unit EH STD AgPdCu
Probe diameter um 35 35 35
Wire length mm 50 50 50
Probe force gf 2.2 2.7 2.4
Tip shape - Round Round Round
Probe Tip
Evaluation items• Characterization:
– Discoloration (200℃)– Deformation with long contact (200℃)– Contact resistance (-40 ℃, RT, 200℃)– Probe marks (-40 ℃, RT, 200℃)– Current carrying capacity
• Durability test – 1 Million TD (200℃)
16Author
DiscolorationEH color hardly changes, it does not cause alignment error
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initial 200℃ 5min 200℃ 10min 200℃ 60min
STD
EH
AgcuPd
Acceptable
Acceptable
Deformation with long contactMethod• Apply OD for 20 minutes• Check for probe deformation and measure
probe force
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EHSTD AgPdCu
ConditionsChuck Temp:200℃Over drive:100umContact time:20min
LGP
UGP
LGP
UGP
WaferWafer
without OD with OD
Probe
Initial
Deformation with long contact/ResultContact at very high temperature results in deformed probe for the standard material and AgPdCu alloy.
EH probe material shows slight deformation only, it provides superior heat resistance to other materials.
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EHSTD AgPdCuEHSTD AgPdCu
AfterBefore
EH
0
1
2
3
0 20 40 60 80 100
Forc
e (gf
)
OD(um)
Probe force
Before After
Recrystallization
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After 300℃ 0.5hBeforeEH EH
• EH probe material composition results in fine crystals even when exposed to high temperatures.
Test 4 Test 4
02468
10
0 100 200 300 400 500
R(Ω)
CRes (no cleaning) LT
02468
10
0 100 200 300 400 500
R(Ω)
CRes (no cleaning) RT
Contact resistance at room and low temperature
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EH RTConditionsUF3000EXBlank AL Wafer 8 Inch (Thickness: 1µm)
Impressed Current: 10mATemperature: RT/-40℃OD: 50umTD: 500n=10No cleaning
EH -40℃
The contact resistance is stable at room temperature and low temperature.
02468
10
0 100 200 300 400 500R(
Ω)
CRes (no cleaning) HT
02468
10
0 100 200 300 400 500
R(Ω)
CRes (no cleaning) HT
02468
10
0 100 200 300 400 500
R(Ω)
CRes (no cleaning) HT
Contact resistance at 200℃
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STD
EH
AgPdCu
ConditionsUF3000EXBlank AL Wafer 8 Inch (Thickness: 1µm)
Impressed Current: 10mATemperature: 200℃OD: 50umTD: 500n=10
Cleaning: No cleaning
02468
10
0 200 400 600 800 1000
R(Ω)
CRes (with cleaning) HT
02468
10
0 200 400 600 800 1000R(
Ω)
CRes (with cleaning) HT
02468
10
0 200 400 600 800 1000
R(Ω)
CRes (with cleaning) HT
Contact resistance at 200℃
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STD
EH
AgPdCu
ConditionsUF3000EXBlank AL Wafer 8 Inch (Thickness: 1µm)
Impressed Current: 10mATemperature: 200℃OD: 50umTD: 1000n=10
Cleaning: each 200TDSheet type: WA6000-SWEOD: 60umTD: 20
Probe mark
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RT 200℃ -40℃
Probe mark
Width(um) 7.5 7.1 7.9 8.7 7.1 71
Length(um) 6.5 5.9 7.8 7.4 6.1 6.2
Depth(um) 0.37 0.49 0.46 0.41 0.28 0.35
Small and shallow probe marksBlank AL Wafer 8 Inch (Thickness: 1µm)OD: 50um
Current Carrying Capacity (CCC)
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ConditionsTemperature: RTOD : 80umTime: 2minn=3 EH
AgPdCu
STD
20%DOWN
CC
C 600m
A
-15
-10
-5
0
5
10
15
-15 -10 -5 0 5 10 15
Initial
-15
-10
-5
0
5
10
15
-15 -10 -5 0 5 10 15
TD 1000k
Durability (1000 kTD)
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ConditionsUF3000EXBlank AL Wafer 8 Inch (Thickness: 1µm)
Temperature: 200℃OD 80umTD 1millionn=35Cleaning: each 200TD
DY(um)
DX(um)
DY(um)
DX(um)
Probe Tip
Initial 1000 kTD
02468
10
0k 200k 400k 600k 800k 1000k
Plan
arity
(um
)
Planarity
Durability (1000 kTD)
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After 1000 k TD
ConditionsUF3000EXBlank AL Wafer 8 Inch (Thickness: 1µm)
Impressed Current: 10mATemperature: 200℃OD: 50umTD: 1000n=20
Cleaning: each 200TDSheet type: WA6000-SWEOD: 60umTD: 20
02468
10
0 200 400 600 800 1000
R(Ω)
CRes (with cleaning) HT
02468
10
0 200 400 600 800 1000
R(Ω)
CRes (with cleaning) HT
Initial
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Item Supporting temperature Result
Discoloration 200℃ Good
Deformation 200℃ Superior
Contact resistance -40℃~200℃ Superior
Probe mark -40℃~200℃ Good
CCC RT 600mA
Durability test 200℃ 1000 kTD
EH probe performance summary
Conclusion
EH probe material is a solution for test up to 200℃
• EH probes provide superior mechanical stability at high temperature.
• EH probe is not subject to discoloration, this prevents prober set-up issue.
• EH provides superior contact resistance stability.
• EH probe low resistivity results in higher CCC than common AgPdCu alloys.
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• Special thanks to our material and wire drawing suppliers for their partnership and relentless efforts and perseverance .
Acknowledgements
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• Special thanks to the high temperatureprobe project team at Nidec SV TCL for theirhard work & dedication in preparingdata used in this paper:
• Special thanks to management at Nidec SVTCL for their invaluable inputs regardingtopic selection & review of this paper:
– Koji Ogiwara
– Daisuke Miyamoto– Engineering team
– MFG team
Thank you