ROUTE60™: a new vertical probing technology

Raffaele Vallauri
STMicroelectronics
ROUTE60: a new
vertical probing
technology
June 3-6, 2007
San Diego, CA USA

Authors
R. Vallauri – STMicroelectronics
M. Gervasoni – STMicroelectronics
R. Crippa – Technoprobe
S. Lazzari – Technoprobe
June 3-6, 2007
IEEE SW Test Workshop
2

Table of contents
ROUTE60 Technology Introduction
Qualification on a 80 μm linear pitch, automotive
product at three temperatures
Production results on 65 μm linear pitch devices
Scrub depth analysis at ROOM T and at +125°C
Evaluations of probing on pad over active areas
Conclusions
Follow-On Work
June 3-6, 2007
IEEE SW Test Workshop
3

Technology Introduction - Needles
Buckling Beam style: higher possibility to control
the gram force
Needle section equivalent to 3 mils ∅ wire:
Robust mechanics
High current capability
Flattened section of needles
allows fine Pitch applications
down to 60μm
Patented
June 3-6, 2007
IEEE SW Test Workshop
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Technology Introduction - Design
Gram Force adjustable between 5 to 8 g
Small scrub action proportional to OD
Tight Alignment: ±10 μm
Planarity range : 40 μm
Temperature range: -45 ÷ +150°C
Hard Ceramic:
CTE 3.3 ppm/°C close to Silicon
Low needles friction
Needles Assembly: no template required, easy tip
replacement
June 3-6, 2007
IEEE SW Test Workshop
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Qualification on a 80μm pitch product
Embedded Flash Microcontroller for automotive
market
Small pad opening (65μm × 70μm)
Up to 4 EWS Tests, 3 testing temps – KGD flow
Small probing process margins with present
Epoxy probe cards mainly @ HOT temp:
Passivation breakage
Large scrub marks impacted area
Benchmark with Epoxy probe cards
June 3-6, 2007
IEEE SW Test Workshop
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Product test flow description
Package Flow:
EWST1 @ Room T -
Vertical //32
Bake (24 h)
EWST2 @ Room T -
Vertical //32
EWST3 @ Room T -
Epoxy //4
KGD Flow:
EWST1 @ Room T -
Vertical //32
Bake (24 h)
EWST2 @ + 125°C -
Vertical //16
EWST3 @ + 125°C -
Epoxy //4
EWST4 @ - 40°C -
Epoxy //4
June 3-6, 2007
IEEE SW Test Workshop
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Probe Cards Pictures
Epoxy
Vertical
ROUTE60
June 3-6, 2007
IEEE SW Test Workshop
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Electrical results @ ROOM T (EWS3)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
88,8% 88,9%
1,4% 2,4%
0,1% 0,9%
ROUTE60
Epoxy
Retest rate: -1.0%
Gain rate: -0.8%
Yield
Retest
Gain
June 3-6, 2007
IEEE SW Test Workshop
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Electrical results @ +125°C (EWS3)
100%
90%
80%
70%
95,3%
95,1%
60%
50%
40%
30%
Yield
Retest
Gain
20%
10%
0%
2,0% 3,6%
0,6%
1,5%
ROUTE60
Epoxy
Retest rate: -1.6%
Gain rate: -0.9%
June 3-6, 2007
IEEE SW Test Workshop
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Electrical results @ -40°C (EWS4)
100%
90%
80%
70%
97,8%
96,2%
60%
50%
40%
30%
Yield
Retest
Gain
20%
10%
0%
1,3% 0,6%
3,0%
ROUTE60
Epoxy
2,0%
Retest rate: -1.7%
Gain rate: -1.4%
June 3-6, 2007
IEEE SW Test Workshop
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Mechanical Results @ +125°C: ROUTE60
CENTER
SCRUB
VITRIF
X
Y
L
W
L
W
TIME 0
AGEING
UL N/A N/A 32,5 32,5 N/A N/A
LL N/A N/A 10 10 2 2
AVE 33,0 36,0 13,7 14,5 29,4 26
STDEV 4,6 2,5 1,5 1,1 2,8 3,5
C P N/A N/A 2,5 3,4 N/A N/A
C PK
AVE 32 34,3 13,8 14,1 27,6 24,9
STDEV 3,2 2,4 1,6 1,5 2,8 3,4
C P N/A N/A 2,3 2,5 N/A N/A
C PK
N/A N/A N/A N/A 3,3 2,3
N/A N/A N/A N/A 3,0 2,2
June 3-6, 2007
IEEE SW Test Workshop
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Scrub mark pictures @ +125°C
Epoxy
Damaged Area: 9.4%
ROUTE60
Damaged Area: 4.1%
PAD DAMAGE is largely reduced using vertical
probe cards: more than 50% of reduction
June 3-6, 2007
IEEE SW Test Workshop
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65μm Pitch Product Vehicle Results
Small pad opening (58μm × 71μm)
Up to 2 EWS Tests, ROOM T, //8
Small probing process margins with Epoxy
probe cards :
Passivation breakage
Large scrub marks impacted area
Contact issues
Benchmark with Epoxy probe cards
June 3-6, 2007
IEEE SW Test Workshop
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Electrical results after EWS1 and EWS2
100%
95%
Yield% (EWS1+EWS2)
90%
85%
80%
75%
70%
1
3
5
7
9
June 3-6, 2007
EPOXY
11
13
15
17
19
Lots
ROUTE60
Epoxy: 88%
ROUTE60: 96%
IEEE SW Test Workshop
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23
25
27
29
31
33
Yield
Avg
15

Scrub mark pictures
ROUTE60 on 58×65 μm pads
at 65 μm pitch
June 3-6, 2007
IEEE SW Test Workshop
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Mechanical Results
Alignment:
Planarity:
Align (μm)
16
14
12
10
8
6
4
2
0
0 kTD 130 kTD
Plan (μ m)
25
20
15
10
5
0
-5
-10
-15
-20
-25
0 KTD 130 KTD
June 3-6, 2007
IEEE SW Test Workshop
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Evaluations on pads over active areas
14
12
Gram Force Cobra vs. ROUTE60
Gram Force
10
8
6
4
2
0
Cobra 2.5 mils
Cobra 3 mils
Route60 (Fmax=5.5g)
Route60 (Fmax=6.5g)
Route60 (Fmax=8g)
0 50 100 150 200
OD (μm)
Gram Force adjustable between 5 to 8 g
June 3-6, 2007
IEEE SW Test Workshop
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Scrub depth analysis @ ROOM T – 1TD
0,8
0,7
Scrub depth (µm)
0,6
0,5
0,4
0,3
0,2
0,1
0
1 TD – 8g PH
50 60 70 80 90 100 110 120 130
Overdrive (µm)
June 3-6, 2007
IEEE SW Test Workshop
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Scrub depth analysis @ +125°C – 9 TDs
6.5 g PH – Average scrub depth : 1.30 µm
5 g PH – Average scrub depth : 1.15 µm
June 3-6, 2007
IEEE SW Test Workshop
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6M2T pad over active
Bonding
point
Probing
point
C
O
B
E
D
G
E
M6
M5
M4
M3
M2
M1
BPO: 59 x 123µm
No cracks observed till 125 μm X 6 TDs @ ROOM T
with both 8g and 6.5g probe heads
June 3-6, 2007
IEEE SW Test Workshop
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3M0T pad over active area
Bonding
point
Probing
point
BPO
65μm x 108μm
M3 pad
Alucap
M3 rails
No cracks observed with 8 g probe head till:
100 μm OD × 9 TDs (6 @ ROOM T + 3 @ +150°C)
125 μm OD × 6 TDs (4 @ ROOM T + 2 @ +150°C)
June 3-6, 2007
IEEE SW Test Workshop
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Conclusions
ROUTE60 is the first vertical probing
technology successfully released to production
in ST, down to 65 μm pitch
The benchmark with Epoxy probe cards showed:
Better electrical contact
Lower pad area damage
The possibility to probe on active areas playing on the
gram force
This technology seems very promising to probe
at 60 μm pitch and on low-k dielectrics
June 3-6, 2007
IEEE SW Test Workshop
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Follow-on work
1. Probing:
Automotive products, with up to 3 EWS Test
and up to + 125°C / + 150°C
Copper metals and Low-k dielectrics
Probing area down to 50 × 50 μm
2. Evaluations at lower pitch, down to 60μm:
Life test in progress on test cards at +125 °C
3. On-line cleaning optimization
June 3-6, 2007
IEEE SW Test Workshop
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Acknowledgements
A special thanks to:
ST Castelletto EWS Engineering Team
ST Rousset EWS Engineering Team
ST FTM EWS Europe Organization
ST FTM R&D Agrate
ST Automotive Product Group
ST Corporate Package Automation
June 3-6, 2007
IEEE SW Test Workshop
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