Transcript Improve your Yield with AOI and X-Ray

Improve your Yield
with AOI and X-Ray
NEW Show SA March 2010
Keith Bryant
Chairman SMART Group UK
Benefits of Implementing
AOI and X-Ray
Advantage
against MVI
SPC and
Traceability
Cost
Performance
• Approx. 96% Fault
Coverage (AOI)
• Reduction in labour
cost
• High level of SPC
data produced
• High throughput
• Operator cost/
operator training cost
• Real time control and
feedback
• Rework time and cost
• Insurance for supplier
and customer design/
quality issues
• Some things you
cannot see
• Accuracy
• 24/7 Consistency
• Field failure and
customer reputation
BENEFITS
YIELD IMPROVEMENT
COST REDUCTION and IMPROVED QA /QC
AOI at Different Stages
Printer
Reflow
Pick and Place
Measuring the
height and volume
of Solder Paste
Solder Paste
Inspection
• 70% of SMT defects
are caused by poor
print conditions
Placement
inspection
before reflow
Pre Reflow
Inspection
• Defect prevention
• Reducing rework time
and cost
• Controlling height and
• Quality Control
volume of solder paste
contribute greatly to
line quality
Optical
inspection after
reflow
Post Reflow
Inspection
• Defect detection
• Preventing field
failure
• Quality Assurance
SPC management: Analysis and
Implementation
YIELD IMPROVEMENT
2D Composite Color Image Processing
Ordinary Blank & White Image
Composite Color Image
Combines color 2D image and 3D image to obtain high precision paste
measurement under varying PCB surface color, silk print, pad colour conditions.
The zero point is measured from each pad, allowing a wide tolerance against
PCB warpage. The 2D/3D methodology allows for accurate measurements of
insufficient solder, scratches and solder splash and damage on golden fingers.
High accuracy by 2D & 3D combined measurement process
2D inspection
3D Inspection
Measure Solder Deposition Area
Recognize ZERO height on Black area
2D inspection detects lands, silk points, via holes, and traces in order to recognize
precise solder height. Also it measures solder deposition shape. Then calculates the
solder height and volume by 3D Phase shape inspection.
Copyright (C)2008 Saki Corporation. All Rights Reserved.
Variance due to the squeeze direction
Pad shapes may vary by the squeeze direction
Front to Rear
Rear to Front
Squeegee Direction
Squeegee Direction
Min Height : 132um
Max Height : 199um
Difference : 67um
Min Height : 138um
Max Height : 168um
Difference : 30um
Confidential
Interesting AOI statistics
Defect analysis historic example
Detection rating (example)
Defect type
Solder defect
30%
Missing Component 25%
Short
20%
Wrong Type
5%
Polarity error
5%
Thombstone
5%
Other
5%
Lifted Lead
3%
Offset
2%
Coplanarity error
1%
Total
AOI type1 AOI type 2 AOI Type3
70%
90%
95%
85%
95%
95%
80%
90%
95%
70%
95%
70%
95%
95%
90%
70%
80%
95%
90%
90%
90%
75%
75%
90%
95%
95%
99%
10%
10%
50%
AOI Type 1 ~ Correlation
AOI Type 2 ~ Synthetic Imaging
AOI Type 3 ~ Vector Imaging
Results
AOI type1 AOI type 2 AOI Type3
21%
27%
29%
21%
24%
24%
16%
18%
19%
4%
5%
4%
5%
5%
5%
4%
4%
5%
5%
5%
5%
2%
2%
3%
2%
2%
2%
0%
0%
1%
79%
91%
94%
What does this mean
• Type 1, Pure pixel by pixel comparison
• Type 2, Basic shape and feature
recognition software. Comparison
based
• Type 3, Intelligent Raster and
Algorithm based recognition system.
Two cameras or clever lighting
Coaxial Lighting
Much light comes with much shadow...
Standard System
Koaxiale Beleuchtung
CCD camera
Lighting
Lighting
CCD camera
Semi permeable
mirror
Capacitor
Shadow
Capacitor
CCD
Telecentric lens
Telecentric optic eliminates
parallax distortion.
Leading Edge Innovative Design
5 Megapixel Camera
Side Angle Cameras
Illumination
Fusion Lighting
Raising the bar in
defect detection!
•600 high intensity
LED’s
•3 layers of illumination
•4 colours
•Red
•Green
•Blue
•White
YTV Fusion Lighting
Camera Lens
Fusion Advantage
Filters
Real time SPC for Yield Improvement
Copyright (C)2009 Saki Corporation. All Rights Reserved.
Link Between SPI and AOI
Even better systems are coming
Where do you place an AOI System?
 In-Line (for sure if you can afford it)

To check Solder Paste (2.5 or 3D)

To check Part Placement

To check solder post reflow
Solder Paste
Placement
Parts &
Solder fillets
Requirements
of an X-ray machine
70 degree angled view for BGA/CSP’s
High resolution digital image
Good greyscale definition
Large image on screen
Easy to use and program
Produce accurate feedback on faults
Link with rework stations
Why X-ray Inspect?
Why X-ray Inspect?
Lead-free sample
Do I really need X-Ray?
X-ray
ERSA Scope
• Missing ellipse could
indicate open joints
• Very subtle greyscale
differences
• Location of void with
respect to interface is
very clear
Lead-free CSP X-ray Image
Open Connection
What do you think??
Popcorning in
BGAs
Pin-in-Hole Fill %
Calculation
 IPC 610-D requires Class 3
pin-in-hole reflow to have a
minimum of 75% fill
100% Fill
 Good software allows you to
easily measure this
 The cursor automatically
adjusts as you change angle
and magnification
< 75% Fill
Details of example company
T/O €3.8m and making 15% profit
Privately owned and funded
Invested in AOI (in-line)and 2D x-ray (off-line)
Mid volume, medium mix assembly
Reasonable level of Statistical Process Control
Reputation for Quality Products
The results
Yield Comparison: Before and After
Implementation of AOI & X-Ray
8 9 .7 6 %
8 8 .4 3 %
Yield
97.46% 9 9 .5 2 %
97.00%
100.00%
8 5 .9 3 %
80.00%
After
Soldering
After
Placing
60.00%
MVIB
AOI
Before Automation Implementation
MVIP
FCT
After Implementation
of in-line AOI pre reflow
and off-line 2D X-Ray
FQC
Before AOI and X-Ray
Faults were removed within the process
Feedback was patchy and inaccurate
Faults were being produced by
inspection
WIP was high due to rework
The quality reputation of the
company was being maintained at a
huge hidden cost
After the change
• It scared the sh*t out of them
Accurate and consistent feedback on faults
Effective SPC data for each hour worked
Key problem areas highlighted
Changes were made in many areas and to
many procedures
Quality built in, not faults inspected out
Some tangible and intangible
benefits of AOI and X-Ray
Consistent quality 24/7
High level of SPC data produced
Platform for growth, the more hours it is used
the faster the return on investment
Gives customers a warm safe feeling
Insurance against supplier and customer
design/quality issues
Ideal for Continuous Improvement Programs
The “true” cost of remakes
 Considered opinion is that it costs 5.5 times the
original cost, here are some reasons:
 cost of increasing all the component orders
 fast track purchasing and delivery
 rescheduling production to remake the boards
 paying extra set-up and labour costs
 small batch production penalties
 Loss of real production while making it twice
Thank You Very Much
For Your
Time and Attention
Keith Bryant
Chairman SMART UK