1. How to Develop
Qualification Programs
for Lead Free Products
by
Mike Silverman
Managing Partner
Ops A La Carte
mikes@opsalacarte.com
www.opsalacarte.com
(408) 472-3889

2. Abstract
There are significant reliability uncertainties around
Lead-Free Solder.
Even if your product does not need to be compliant,
the materials and processes that make up your
product are changing.
As one major consumer product team concluded,
“doing nothing would double the field failure rate of
the electronics.”
This implies that we must do more than just change
solder and components when transitioning in order to
achieve good reliability. We must also review the
design.

3. Abstract
During this time of rapid transition, there is a
significant new body of knowledge to
understand in order to determine the areas
of greatest risk to the reliability of your
product.
Once we understand the risks, we must then
incorporate this new knowledge into the
redesign of the product.

4. Abstract
In this presentation, we will highlight a few of
these significant risk areas and show how
techniques such as HALT and ALT can
assure that the transition has been
accomplished successfully from the
perspective of Reliability.

5. Risks from Temperature
-55 to 125C,
Effects of Temperature Cycling on Long- 70 minute cycle
Term Reliability of Pb-Free Solder Joints
♦ Can we predict time to failure for Pb-
free solder joints? YES
♦ So, when should you be concerned?
Components highly susceptible to
solder joint fatigue
• Large chip resistors,
• Ceramic BGAs,
10
SAC life / SnPb life
• Leadless ceramic chip carriers,
• Non-underfilled CSPs, 8
• Etc.
Max solder joint temperature greater 6 2512 Resistor on FR4 (25 - 80C)
than 80ºC with dwell times greater
4
than 4 hours
At least one thermal cycle per day and 2
Ceramic BGA on FR4 (0 - 100C)
a desired lifetime of more than 10
years 0
0 100 200 300 400 500
This slide provided courtesy of DfR Solutions Dwell Time (min)

6. Risks from Mechanical Loading
(Effects of Board Flexing, Shock, and Vibration)
♦ Post-reflow handling
Increased risk of failure? Conflicting
results
• Sensitive to time after reflow
Some companies moving to restrict board-
level strain
• From 1000 to 750 to 500 microstrain
♦ Shock and Drop
Some degradation in performance 3.0E-03
Board plating seems to play a large role 2.5E-03
SnPb
PWB surface strain
(SnNi weaker than SnCu) SnAgCu
2.0E-03
♦ Vibration 1.5E-03
SAC worse under low-cycle fatigue, where
1.0E-03
most failures occur
5.0E-04
0.0E+00
1,000 100,000 10,000,000
Cycles to Failure
This slide provided courtesy of DfR Solutions

7. HALT for RoHS at
HALT and HASS Labs
Pb-Free Results at

8. Results
♦ 10 Products went through A-B Comparison of Lead
vs. Pb-Free at HALT & HASS Labs
♦ In all cases, both solder and components were
changed to Pb Free. Boards went through design
review and changes to deal with RoHS issues.
♦ Comparison was between products using Pb
Solder and Pb Components vs. products using Pb
Free Solder and Pb Free Components. We did not
include mixed assemblies in this study (if we had,
conclusions would be different - mixed assemblies have proven to
produce weaker solder joints, especially with certain package types)

9. Results
SUMMARY OF FINDINGS:
♦ No Significant Differences in Limits achieved !!
Two Notes of Caution with this statement
1) In all cases, customers had gone through some level of Design
Review and Design Changes before the HALT – you cannot expect
same results by just changing components
2) A change of limits from HALT does not always mean a change of
reliability because acceleration factor is different between Lead &
Pb-Free. HALT is a means of giving you a good approximation as to
the change in reliability, but to know the exact change (in terms of
MTBF), you must conduct a lower acceleration ALT.

10. Results
Once we have redesigned the product and
re-qualified it using HALT, we can then use
this knowledge to write guidelines for future
products.
There are some generic lead-free design
guidelines that exist, but because this is new
and because of the many variables involved,
most companies are developing their own
and very little public info is available.

11. HALT for RoHS at
National Instruments
Pb-Free HALT Results at

12. RoHS Prototype Builds
♦All real test and measurement products (not
test vehicles)
Prototypes to evaluate RoHS impact on design
and process
All assemblies HALT tested to failure, inspected,
and cross-sectioned
Split builds with RoHS and non-RoHS
Assemblies for comparison
Design and process changes made to increase
robustness
No new RoHS failure modes but earlier onset of
failures seen

13. RoHS Process Highlights
♦Lead-Free Solder used: SAC305 alloy, no
clean
♦Immersion Silver, RoHS-designed PCBs
♦Max Temperatures Reached: ~ 255C
♦Incoming XRF validation on all parts

14. RoHS HALT Failure Analysis
♦ Cracked Solder ♦ PCB Laminate
Joint: BGA ball to Cracks – BGA, also
BGA substrate called “pad
cratering”

15. RoHS HALT Failure Analysis
♦ Cracked traces to ♦ BGA pads
BGA pads – outer separated from PCB
rows

16. RoHS HALT Failure Analysis
♦ Cracks in BGA ♦ Laminate Cracks -
Laminate Repair

17. RoHS Prototypes: HALT
Failure Analysis
♦Changes made as a result of FA:
Enhanced ICT (In Circuit Test) Strain Test
Process
• Reduced allowable strain from 1000 to 500 uE
Restricted choice of PCB laminates
Widened BGA traces, tear-dropped pads where
feasible
Restricted # and types of repair allowed
Modified receiving processes: Added checks,
XRF
Modified manufacturing processes

18. HALT for RoHS at
Xantrex
Pb-Free HALT Results at

19. Objectives
♦HALT products in the following order:
Consumer product specifications: 0°C to +40°C (<$100).
Residential product specifications: 0°C to +40°C.
Portable/Towable product specifications: -10°C to +60°C.
Programmable product specifications: 0°C to +50°C.
Vehicle/Distributed product specifications: -25°C to +65°C.
♦Determine robustness of RoHS products.
♦Comparisons done on identical designs.
♦Design issues will be resolved later.
Note: All HALTs done on a QualMark OVS2.5xLF
and OVS3 Typhoon chambers.

20. HALT Results for
175Watt Inverter
♦ Four each Pb-based and RoHS units were compared.
♦ The Pb units died at 5, 15, and 25Grms.
Lead RoHS
Cold -40°C -30°C
Hot 100°C 90°C
Rapid -50°C/80°C -50°C/80°C
Vibration 18Grms 22Grms
Must Meet -30°C/80°C -30°C/80°C
# Units 4 4

21. HALT Results for
100-200Watt Inverters
Lead Lead Lead Lead RoHS
Cold -50°C -50°C -20°C -20°C -20°C
Hot 90°C 90°C 70°C 79°C 65°C
Rapid -50°C/80°C -50°C/80°C -20°C/70°C -10°C/75°C -20°C/60°C
Vibration 6Grms Not done 5Grms Not done 23Grms
Must Meet -30°C/80°C -30°C/80°C -30°C/80°C -30°C/80°C -30°C/100°C
# Units 4 4 4 4 4

22. HALT Results for 1KW Residential
Inverter/Charger
Lead RoHS
Cold -20°C -30°C
Hot 70°C 70°C
Rapid -20°C/60°C -20°C/60°C
Vibration 28Grms 25Grms
Must Meet -30°C/80°C -30°C/80°C
# Units 4 4

23. HALT Results for 1KW Residential
Inverter/Charger
Lead RoHS
Cold -35°C -50°C
Hot 110°C 100°C
Rapid -40°C/95°C -40°C/90°C
Vibration >22Grms >24Grms
Must Meet -30°C/80°C -30°C/80°C
# Units 22 2

24. Some Questions…
♦Any cost increase of RoHS vs Pb parts?
Less than 5%.
♦Should HALT dwell times change with RoHS?
No. The air exchange rates are very high.
♦With RoHS, can I use the Pb HASS profile?
This is dependant on the OL and DL encountered.
If the same, then yes. If not, then investigate root
cause and make determination. Recommend
rerunning life portion of POS.

25. Next Steps
1) Determine if you are going to transition to
RoHS
2) Review your environment and assess the
risks
3) Develop a customized test plan to mitigate
the risks
4) Carry out the testing and feed the results
back into the design process
…and of course, we can help you with all of these.

26. ANNUAL RELIABILITY SYMPOSIUM
May 7-11, 2007
Santa Clara, CA
1) Design for Reliability (DfR) - Learn the building block tools for reliability during the concept
and design phase. May 7-8
2) Design for Manufacturability (DfM) - Learn what tools are needed to produce great products
with high quality. May 9
3) Design for Warranty Cost Reduction (DfW) - Introduces a proven warranty event cost model
that helps identify warranty cost red. Solutions. May 10
4) Design of Experiments (DoE) - Includes basic statistics behind a DOE as well as a workshop in
which we perform a DOE on a specific product. May 9-10
5) Best Accelerated Reliability Test Methods: HALT, ALT, and RDT – This course will review
each of the best Accelerated Test Methods and show when to use each. Great for those already
familiar with the concepts of HALT as well as those that are newcomers to the field. May 7-8
6) Fundamentals of Climatic Testing - Review the different types of climatic tests—temperature,
humidity, altitude, rain, solar, salt/fog, & more. May 9-10
7) Software Reliability - Highlights “best practices” in S/W Reliability and explains their
application & positive impact to each of the development life cycle phases: Concept, Design,
Implementation, & Testing. May 11

27. NEW TEST LAB
Ops A La Carte LLC is proud to announce that we now own and operate
HIGHLIGHTS ABOUT
• Tested over 500 products in over 50 different industries
• Second oldest HALT facility in the world, established in 1995 (originally owned by QualMark)
• Most experienced staff with over 50 years of combined experience in HALT and HASS
• We only use degreed engineers to run all our HALT.
• HALT equipment has all latest technology – only lab in region
• Our HALT/HASS services are fully integrated with our other consulting services.
• We provide HALT/HASS services on a world-wide basis, using partner labs for tests outside California.
990 Richard Ave., Suite 101
Santa Clara, CA 95050
(408) 654-0499
HALT and HASS Labs www.haltandhasslabs.com Ph: (408) 654-0499 Fx: (408) 255-5789
990 Richard Ave., Suite 101, Santa Clara, CA 95050

28. TEST LAB CAPABILITIES
HALT & HASS Labs adds two more pieces of Reliability Test equipment.
In addition to our two HALT chambers, we now have an electro-dynamic
shaker capable of doing two axis sine and random, and we also have a
Combined Temperature/Humidity chamber. Both chambers add versatility
to the types of reliability tests we can perform.
HERE IS A LIST OF SOME OF THE SPECS WE CAN TEST TO:
• DO160
• IEC
• IEEE
• ISTA/ASTM
• JEDEC
• MIL-STD-810
• SAE
• SEMI
• Telcordia
• and more
HALT and HASS Labs www.haltandhasslabs.com Ph: (408) 654-0499 Fx: (408) 255-5789
990 Richard Ave., Suite 101, Santa Clara, CA 95050