1. The document discusses challenges with reballing BGA packages from lead-free to tin-lead metallurgy. It provides an overview of reballing processes and test results. 2. Testing showed that reballed parts performed similarly to original parts in terms of ball shear strength and thermal cycling. However, some reballers showed poorer vibration and shock resistance. 3. Customer surveys found that reballing is an acceptable option for repair and upgrading older electronics. Qualification remains important to ensure quality and reliability.

1. © 2004 -–2200011070
BGA REBALLING FROM
PB-FREE TO SN-PB METALLURGY
MDA PMAP Meeting
March 21, 2011 Huntsville, MD
Greg Caswell
DfR Solutions, College Park, MD, USA
gcaswell@dfrsolutions.com
Joelle Arnold,
DFR Solutions, College Park, MD, USA
jarnold@dfrsolutions.com

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Computer
53%
Consumer
17%
Communications
15%
Industrial
9%
Auto
5%
Military
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Semiconductor International Association

4. Reballing Option For Lead-free Risk Management
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(See Mil/Aero Lead-free Electronics Research Phase 1 report at:
http://www.navyb2pcoe.org/b2p_news.html)

8. Reballing Challenges
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18. BGAs are complex packages
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20. SBIR Tasks
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21. Reballing Customer Survey
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Large void
Missing Ball

28. Ball Shear
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• Ball shear force
distributions
• Relatively equal
average strength
• Native SnPb balls have
greater standard
deviation
• May indicate that
initial balling may be
lacking sufficient
process controls

29. Thermal Cycling
© 2004 - 200107
On Board Thermocouple Measurements
150
130
110
90
70
50
30
10
90000 90050 90100 90150 90200 90250 90300 90350 90400
Time (m)
T (°C)
Reballer A
Reballer B
Reballer C
Reballer D
Reballer E
Native
SnPb
SAC305
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31. Vibration
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BAE Systems- activity
Reballing Process:
•Flowing wave ball removal
•Convection SMT attachment
© 2004 - 200107
Ball
Dia.
Ball
Pitch
Ball
Extents
(LxW)
Die
Size
M90 13x10x0.65 0.45 0.8 11.2 x 6.4 7.53x6.79
L256 17x17x1.25 0.5 1.0 15 x 15 4.28x3.94
F473 19x19x1.12 0.4 0.8 17.6 x 17.6 6.23x5.68
X1148 35x35x 2.8 0.6 1.0 33 x 33 19.3x13.6
(mm)
BGA
Pkg
Dims.
(LxWxT)

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L256
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125
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-125
-150
25 100 125 150 175 183 200 220 230 245 230 220 200 183 175 150 100 25
Temperature (°C)
Warpage (microns)
#1 As Received
#5 As Recevied
#4 Reballed
#6 Reballed
M90
150
125
100
75
50
25
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-25
-50
-75
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-125
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25 100 125 150 175 183 200 220 230 245 230 220 200 183 175 150 100 25
Temperature (°C)
Warpage (microns)
#1 As Received
#5 As Recevied
#6 Reballed
#8 Reballed
F473
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125
100
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50
25
0
-25
-50
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-125
-150
25 100 125 150 175 183 200 220 230 245 230 220 200 183 175 150 100 25
Temperature (°C)
Warpage (microns)
#1 As Received
#7 As Recevied
#6 Reballed
#8 Reballed
X1148
150
125
100
75
50
25
0
-25
-50
-75
-100
-125
-150
25 100 125 150 175 183 200 220 230 245 230 220 200 183 175 150 100 25
Temperature (°C)
Warpage (microns)
#27 As Received
#31 As Recevied
#21Reballed
#22 Reballed
Postive
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PNoegsaittiivvee

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Temperature (deg C)
Warpage (micron)
Pb-Free #1 Pb-Free #7
Model (95% filled, 100C Tg) Model (94% filled, 100C Tg)

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Time (min)
Maximum Relative Stress
240
200
160
120
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40
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Temperature (deg C)
SMT Reflow Stress Actual Ball Removal Profile Stress
Higher Temp. Ball Removal Stress SMT Reflow Die Temp.
Actual Ball Removal Profile Die Temp. Higher Temp. Ball Removal Die Temp.

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