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December 5, 2017

Moisture Sensitive Components in Flooded Storage Facility

A storage facility was flooded and 10.000 packages of SMD/SMT electronic components and materials were exposed to moisture over 85% RH for several days. For high quality reasons the plan is to discard all these components. Is this the best solution? Do we have any alternatives?

R.K.

Experts Comments

Short answer, there are probably alternatives. Whether they are worth it depends on the value of the components, including their logistical value (may be low cost, but long leadtime). If stored properly in MBB (Moisture Barrier Bags) the high RH over the short term should have no impact on the components inside the bags. Biggest concern would be fungal growth on any outer packaging.

If not stored in MBBs, that's another matter. For parts that have MSL > 1, either they need to be baked, or discarded. Baking may have an impact on solderability particularly if the solderability was marginal to begin with. The high moisture environment can also encourage oxidation (micro-layers of water are present on surfaces at humidities > 85%). If the part cost is low enough and replacements can be obtained, then it's probably best to discard and replace any parts not stored in MBBs.

I'd take the approach of assigning risk level based on part cost/availability and MSL, recover what is easily recoverable with low risk, and also attempt recovery of components that are very high cost and/or difficult to replace, then discard the remainder.

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Fritz Byle
Process Engineer
Astronautics
Fritz's career in electronics manufacturing has included diverse engineering roles including PWB fabrication, thick film print & fire, SMT and wave/selective solder process engineering, and electronics materials development and marketing. Fritz's educational background is in mechanical engineering with an emphasis on materials science. Design of Experiments (DoE) techniques have been an area of independent study. Fritz has published over a dozen papers at various industry conferences.
I would ask the component manufacture. I know you can bake a lot of the different components in a convection standalone oven to remove the moisture. This is a common practice for some components. The amount of time and temperature used should be described by the manufacture of the part(s). In some cases, this might not be required. The component manufacture would have to provide this information.
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Michael Kaminsky
Sr Fiald Applications Support Engineer
Kester Inc.
Mr. Kaminsky has 30+ years of circuit board soldering assembly experience along with a patent for wave solder VOC flux process.
A possible solution is to bake the components in an nitrogen atmosphere at 100 deg. C for about 2 hours. Then run some of the components in their reflow process and see if they will survive the reflow regime.
Gregory Arslanian
Global Segment Manager
Air Products & Chemicals, Inc.
Mr. Arslanian has been involved in electronics packaging processing and equipment since 1981 including flipchip, TAB, wirebonding and die attach. Current responsiblities include R&D, applications, marketing and customer interaction.
Depending on the MSL level, they could be baked out. This bake would take dedicated ovens potentially many weeks. This would reset the clock for floor life, but still would not address potential corrosion / oxidation issues. You will need to decide if the cost of the components outweighs the cost of baking and potential solderability issues in the future.
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Mark Waterman
Engineer / Trainer
Electronic Controls Design, Inc. (ECD)
Mark Waterman is a trainer and field engineer with 17 years experience in service and applications specialties. Intimate knowledge of soldering processes and measurement systems. Six sigma and statistical process control generalist.

Unless the moisture exposure has damaged the component or the packaging mechanically or aesthetically, or there was direct contact between the component and the water that may have contaminated or oxidized the components leads, they can be "recovered" per the IPC.

J-Std-033 has a provision for "baking" the moisture from components whose exposure has exceeded the "floor life" time, which is a function of the component's Moisture Sensitive Level (MSL). The bake times and temperatures are listed in Table 4-1 of the standard, and it varies from hours to weeks, depending on the MSL of the component and the chosen bake temperature.

Now the value of the component, and the cost in time, effort and energy needed to "bake" them should be considered as well. It simply may not be worth the cost to bake some of the components. And since oxides have likely started on some of the component's leads, even after baking to clear the moisture from their interior, care should be take when soldered to make sure soldering is not affected, which may be as simple as using a different (more aggressive) flux/paste.
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Paul Austen
Senior Project Engineer
Electronic Controls Design Inc
Paul been with Electronic Controls Design Inc. (ECD) in Milwaukie, Oregon for over 34 years as a Senior Project Engineer. He has seen and worked with the electronic manufacturing industry from many points of view, including: technician, designer, manufacture, and customer. His focus has been the design and application of thermal process measurement tools used to improve manufacturing processes like: mass reflow and wave soldering, bread baking, paint and powder curing, metal heat treatment and more.

It's unfortunate this happened. The safest way is to discard these components to avoid any quality concerns. If you need to try to use them, there are industry standards and best practices available to inspect, test, and qualify the devices. If these components are stored in vacuum MBB (Moisture Barrier Bag) with HIC (Humidity Indicator Card), it's not impossible for them to survive this incident.

It's what's inside the MBB that really matters. MBB is supposed to keep moisture out indifinitely even the room is humid. You can refer to JEP-160 and J-STD-033 on information pertaining to storage, testing, and use. Hope you come to a good resolution on this matter.

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Jerry Liu
Sr. Manager, Obsolescence Management
Cymer, Obsolescence Biz Experts
20+ years in the Semiconductor Capital Equipment industry. Served in various capacities including applications, product marketing, product lifecycle management, business operations, and program management in KLA-Tencor and Cymer. Founded Obsolescence Biz Experts to encourage collaboration across industries.

The best thing to do would be to contact the component manufacturers for their recommendation.

If they do not provide a solution, you can try baking the components. But that would be quite a task to bake 10000 components.

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Eric Bastow
Senior Technical Support Engineer
Indium Corporation
Eric is an SMTA-certified process engineer (CSMTPE) and has earned his Six Sigma Green Belt from the Thayer School of Engineering at Dartmouth College. He is also a certified IPC-A-600 and 610D Specialist. He has an associate's degree in Engineering Science from the State University of New York and has authored several technical papers and articles.

Component use after plant is flooded and parts are over the 60 RH limit for 36-48 hours is usually the specification most abide to. As long as the components are not soaked in water humidity is still an issue yes but is usually fixed by drying in a vacuum drying oven for 24 hours at 125c or 36 hours for 36 hours. These are sold by oven manufacturers or failure analysis labs usually have them and can offer that service. Humidity when related to rework.

When Pcb's which are built come back to united states to be reworked at rework contractors or OEM's. these Pcbs are subject to similar issues if from Asia or Mexico. Asia humidity can be similar up to 90% at certain times of the year or Pcbs are stuck in trucks or in sea freight waiting to be shipped.

These are commonly dried to 100c for 8 ours but components are soldered to PCBS so slightly different specification as they can also be shipped in desiccator protected bags. Drying these parts should be Ok but tested by functional tester such as burn in tester to be sure its safe is my recommendation.

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Paul Wood
Advanced Applications Manager
OK International
Mr. Wood has been with OK International for 35 years and has been involved in the design of all rework products. He is a global expert in circuit board and electronics rework and has travel world wide supporting customer applications .

OK, so we know that these components were exposed to excessive moisture for an extended period of time. My belief has always been rather be safe than sorry.

I cannot imagine how much baking time would be required to bring these components to a safety level acceptable to either your client, if you are a CM, or to your own spec if you are an OEM.

Hopefully you were fully insured because my opinion is take the money & run!

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Jerry Karp
President
JSK Associates
Based in. Northern California since 1971. Founded JSK Associates in 1979. Actively involved in soldering, cleaning, chemistries. 30 years experience in EOS/ESD control.

As the material were not stored in ambient condition for several days, It's always advised to discard such components, as those components will have observed too much moisture, which could lead to internal cracks, oxidation problem effecting solderability & reliability of product at later stage.

When a material exposure time exceeds the time stated on the Humidity Control Card, most industry refer J-STD-022 & J-STD-033 standard, but in this case the components are stored and packed in good conditions. Also, whether to use it or not will all depend on the application you use.

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Swaroop Pawar
PCBA Industrialization
Schneider Electric
Have 18 years of experience in electronic Industrialization. Specialties in PCB Design & manufacturing process, PCBA Process Development and Continuous Improvement.
Don't discard. If they were in desiccant bags, you should expect no impact. And then there is option of baking. It is a little complicated subject but discarding these components should be considered only after you have explored some other options.
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Ray Prasad
President
Ray Prasad Consultancy Group
Ray Prasad is the founder of Ray Prasad Consultancy Group which provides teaching, consulting and technical expert services in tin-lead and lead free technologies using SMT, BGA, BTC, fine pitch and through hole components. Mr. Prasad is a long time member of IPC, and is currently the chairman of BGA committee IPC-7095 "Design and Assembly Process Implementation for BGA" and Co-Chairman of recently created IPC-7093 "Design and Assembly Process Implementation for Bottom Terminations" surface mount Components (BTCs) such as QFN, DFN and MLF.

From your question it appears that the components were not submerged with the flood waters. If this is the case then they may be salvaged by washing in a mild alkaline soap if no corrosion is present.

I have been contacted by companies over the years that have tried to salvage complete PCB assemblies that have had flood damage. Most of the time it is an exercise in futility.

Flood waters are filled with many types of pollutants. The enormous amount of storm water will overwhelm treatment facilities, washing chemicals and toxic substances into the mix, including raw sewage, crude oil, and pesticides. Personally if I were in your situation I would settle with the insurance company and discard them.
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Charlie Pitarys
Technical Expert Sales Support
Kyzen Corporation
Charlie Pitarys has over thirty years of industry experience and has been with KYZEN for twenty-one years. Charlie is a former Marine and a retired Sargent First Class in the Army Reserves. His previous employers include Hollis and Electrovert. Charlie continues to use his expertise on cleaning processes and machine mechanics to help KYZEN customers and partners improve their cleaning operations.
If the parts were flooded (e.g., exposed to 100%RH for several days via immersion under water) then my recommendation is to discard/destroy the parts permanently. A component risk mitigation strategy to salvage these compromised parts contradicts your "high quality" statement .
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Mark Northrup
VP of Advanced Technical Operations
IEC Electronics
Mark has over 25 years' experience in electronics fabrication, quality and reliability while working for IEC Electronics, GE, Motorola, ORS, etc. He has most recently established Dynamic Research and Testing Laboratories, LLC now rebranded as IEC Electronics Analysis and Testing Laboratory, LLC in Albuquerque, NM for electronics and material analysis testing in the military, medical, and industrial industries. His area of expertise includes PCB, PCBA, components, analytical and electrical analysis techniques.

Your recommendation to discard the components is the best solution from my perspective. Exposure to high moisture will impact the solderability of the component, and will also be detrimental to the functionality of the components. The porosity of the component body may have been compromised and moisture within the component body would create problems during the reflow process.

This was found and documented during the introduction to the surface mount process back in the 80s. Depending upon the construction materials of the components, the moisture would change phases from a liquid to a gas, increasing the pressure within the component and during reflow process and would blow the bottoms (i.e. destroy) of the components reducing their reliability to another degree.

Using analogies, I would not buy a used car from Houston anytime in the near future and I would not buy those components. I would also suggest getting in touch with your insurance company as these may be covered under one or your company riders.
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Leo Lambert
Vice President, Technical Director
EPTAC Corporation
At EPTAC Corporation, Mr. Lambert oversees content of course offerings, IPC Certification programs and provides customers with expert consultation in electronics manufacturing, including RoHS/WEEE and lead free issues. Leo is also the IPC General Chairman for the Assembly/Joining Process Committee.
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