New probe tip fabricated by MEMS (LIGA process) for no ...June 3, 2003 2. 2003 Southwest Test...
Transcript of New probe tip fabricated by MEMS (LIGA process) for no ...June 3, 2003 2. 2003 Southwest Test...
2003 Southwest Test Workshop
New probe tip fabricated by MEMS (LIGA process) for no-cleaning test
Tsuyoshi Tsuyoshi HagaHaga,, K.Okada, J.Yorita, Y.Hirata, S.Shimada*
Harima R&D Department Osaka R&D Laboratories*Analysis Technology Research Center
Sumitomo Electric Industries, LTD.
June 3, 2003 1
2003 Southwest Test Workshop
OutlineMEMS probe background Introduction of micro contact-probe fabricated using LIGA process
Benefits of no-cleaning test
Analysis of scrubbing motion
Design of cleaning-free shape
Sharpening of LIGA probe tip
Verification of no-cleaning operation
ConclusionsJune 3, 2003 2
2003 Southwest Test Workshop
Background of MEMS probe<Requirements>
・Fine pitch capability (Down to 50µm or less?)・Multi test (64DUT → 128DUT → wafer level?)・High frequency test (at speed testing GHz)・Low cost testing ・High reliability
・Limit of conventional machiningAccuracy,Shape,etc.
・Increase of conventional machining cost
LIGA(MEMS)LIGA(MEMS)・・High accuracy,high aspect ratio MEMS technologyHigh accuracy,high aspect ratio MEMS technology・・Mass production process based on XMass production process based on X--ray lithographyray lithography
High accuracymicro spring
Low contact force probe tip
June 3, 2003 3
2003 Southwest Test WorkshopAbout LIGA process
<Process flow (LIGA)>(LiLithographie-GGalbvanoformung-AAbformung) <Advantages>
2)Electroforming
Irradiation
Development
Electroforming
Removal of resist
SR(X-ray)
X-ray Mask
Resist
Metal
1)X-ray Lithography
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・High accuracy: ±0.4mm・Good perpendicularly:
0.1µm/100µm・High aspect ratio: 10 or more・High resolution/sharp edge Tip R:< 1µm・Multi material
(metal,plastic,ceramics)
・Mass production process
2003 Southwest Test Workshop
LIGA probePOGO type probe
For array(C4), LCD etc.
Scrub type probe
For Al electrode pad
New material : Ni-Mn alloy Controlled grain size & crystal orientationHigh hardness (HV 600 or more)High toughness
Good electrical resistivity(1.3x10-7Ωm)
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2003 Southwest Test Workshop
Benefits of no-cleaning TestIC Test Profile
Yie
ld
Number of Touchdowns
Conventional probe
Cleaning Cleaning Cleaning
Loss
Adhesion and accumulation of debris at the probe tip
No-cleaning
1)1) Improve yield & throughputImprove yield & throughput2)2) Reduce costReduce cost
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Simulation of scrub action2003 Southwest Test Workshop
Why do adhesion and accumulation of debris occur?Al contact wiping action of truncated pyramid tip(Conventional MEMS probe tip fabricated by Si micro machining)
BackwardForward
4µm
Initial adhesion of Al debris occurs at backward scrub actionat backward scrub action.→ Al debris increase the debris adhesion at next contact.
Backward scrub action is useless for electrical contact.June 3, 2003 7
2003 Southwest Test Workshop
Analysis of scrub motion
1.2mm
1.3m
m
0.06m
m
SEM chamber
Al/Cu coatedSi wafer
Stage(Actuator)
Camera
e-GUN
LIGA probe
Tester
Test condition
Temp. : R.T.Pad material : Al-CuSubstrate : Si
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2003 Southwest Test Workshop
Basic characteristics of LIGA probe
0 20 40 60 80 100 120 140
Contact force (mN)
140
120
100
80
60
40
20
0
Ove
rdri
ve (S
trok
e) (µ
m) 140
120
100
80
60
40
20
0
Len
gth
of sc
rub
(µm
)
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2003 Southwest Test Workshop
Analysis of scrub action
Adhesion!!
⑥⑤Backward ④
③
Electric contact
②Forward ①
Probe Tip : Pillar-shaped structure imitated truncated pyramid tip
June 3, 2003 10
Simulation of no-cleaning shape2003 Southwest Test Workshop
New Type Probe Tip
Forward
Backward
June 3, 2003 11
Design of no-cleaning shape2003 Southwest Test Workshop
55°
55°
R10 µm
R2 µm
R5 µm 45°
22.5°59.35°
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2003 Southwest Test Workshop
No-cleaning shape Fabricated by LIGA
Tip shape
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Sharpening of LIGA probe tip2003 Southwest Test Workshop
Probe Tip
Discharge electrode
Oil
Combination of LIGA and Micro Electro Discharge Machining
Forward
20µm
48µm
Shaving
Scrub Mark
Probe tip
SEM micrograph of discharge scarJune 3, 2003 14
2003 Southwest Test Workshop
Hardness variation of the EDMed surfaces EDMed surface profile
Element density in the depth direction of the recast layer (the recast layer ):C, :Ni, :W, ×:Ti, :O
C Ni
Spattering time (min.)
Inte
nsity
(%)
Depth
(1µm)
Discharge voltage60V
AnnealingAnnealing Carburizing Carburizing
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672±96
After machining(60V)
540±68
After machining(110V)
616±20
Before machining
Hardness(HV)
(Discharge Voltage)
Verification of no-cleaning operation2003 Southwest Test Workshop
Forward ① ③②
Backward ④ ⑤ ⑥
Probe Tip : No cleaning shape
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Verification of no-cleaning operation2003 Southwest Test Workshop
After 10,000 touchdownsBefore touchdownForward side Backward side
Accumulated aluminum
Conventional(trapezoidal) tip
Newly designed(no-cleaning) tipsharpened by µ-EDM
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2003 Southwest Test Workshop
Conclusions
Micro contact probe fabricated by LIGA process (MEMS).
Probe tip sharpening using the LIGA and µ-EDM combination.
New probe tip shape for cleaning free test.
To realize cleaning-free test:
Aluminum debris generation phenomena were analyzed by dynamic SEM.
The scrub simulation technology by applying cutting simulation technology was developed.
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2003 Southwest Test Workshop
Spare
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Cutting tool simulation technology2003 Southwest Test Workshop
3D Machining simulation
Cutting Tool
Tool
IGETARROY
3mm
ToolDebris(Shaving)
For cutting tool shape design & cutting condition analysis
Scrub simulationScrub simulation20June 3, 2003
2003 Southwest Test Workshop
Basic characteristics of LIGA probe
Four terminal method
Substrate
Test ConditionTemp. : R.T.Pad : Al-Cu
0
1
2
3
4
0 20 40 60 80 100 120 140
Con
tact
resi
stan
ce (Ω
)
0
25
50
75
100
Scr
ub le
ngth
(µm
)
ResistanceScrub
OD (µm)
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2003 Southwest Test Workshop
Grain TEM photographNi Grain Size Control
1μm
Conventional Material
Miniaturization of grain sizeHigh hardness: up to Hv600
Good uniformity
Grain size uniformity along thickness
XRD Measurement(Wilson method)
New Material
0.1μm
New Material
Hardness:Hv620
Ave
rage
gra
in si
ze (n
m)
Seed layer side Thickness (µm) Top
Hardness:Hv400-500
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2003 Southwest Test Workshop
Crystal orientation controlCrystal orientation distribution
New material Old material
Seed layer side Thickness (µm) Top Seed layer side Thickness (µm) Top
Control of the seed layerFitting current condition and additive agent
Good uniformity of grain size and crystal orientation along thicGood uniformity of grain size and crystal orientation along thicknessknessJune 3, 2003 23
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Alloy design
High heat resistance Ni alloySuppress NiS,SOx generation
Ni + S → NiS (Very brittle)S + O2 → SOx (brittle)
Sulfur
20nm20nm
NiS,SOxNiS,SOx
Sの添加量を減らす
Sの析出をトラップする
Sulfur
Mn (Trap)
Mn + S → MnS
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1
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
トラップ材に求められる機能トラップ材に求められる機能
Niより強いSとの結合
電析可能である
0
NaMg
Al Ti
MnMn
Mo NiCu
FeSn
Ag
Co
-200 -150 -100 -50
Sta
ndar
d el
ectro
de p
oten
tial (
V)
Electrolysis of water
Electroforming is possible
Free Energy of metal sulfide⊿G(Kcal/gmolS2)
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