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Voiding in Electronics Assemblies: Causes & Mitigation

Phil Zarrow: This video is for engineers working to overcome voiding issues. It will discuss how to reduce voiding through the use of proper process and materials.
Dr. Lee, what are some of the problems that voids cause in solder joint?
Dr. Ning-Cheng Lee: Voids actually cause a lot of conductivity in the solder joint and that causes a local hot spot within solder joint, which in turn, causes directly the rapidity trouble, not to mention mechanically, of what also reduces mechanical strength. Those are the major reasons why the void causes problem.
Phil Zarrow: What are some of the causes of voiding in solder joints?
Dr. Ning-Cheng Lee: The voiding actually is directly caused by the outgassing within the solder joint when a solid is in a molten state. This, I'm guessing, is one source, but many things can contribute and aggravate that. Normally, when looking to the problem of the voiding, you can have source as material, you can have the cause as the process and the profile, and you can also have the design. Those can all contribute to the voiding, so when you try to eliminate the voiding, you cannot just come at one angle to solve the problem. You have to understand what other cause can come from and you have to look at all of them.
Phil Zarrow: You've done a lot of work with regard to void mitigation via the reflow profile. Discuss that a little bit.
Dr. Ning-Cheng Lee: Yes. When we try to design the material to eliminate the voiding problem for the industry, basically we tried to look into it first from our material angle. How to design a material which will not contribute to the voiding? It's two factors on that. One is if you can design material – flux – which will not have outgassing at the higher temperature, you cut out the source of the voiding. Second thing is if you design the flux, which is very good at wetting, then the flux can not hide inside the molten solder joint. Now the angle, you can solve the problem of the voiding. We designed the flux based on those two angles, from a material side. Then, actually, another thing we also helped our customer about, how should they set up their process and also how should they design their device that can minimize the voiding from their angle. That's how we do it.
Phil Zarrow: Very good. Dr. Lee, where can we find more information on how to Avoid the Void?
Dr. Ning-Cheng Lee: We have a compared a bunch of the documents and created and published papers on our website and you can find the help from there. We tried to be very helpful to the industry. That's one we thing we can tell best.
Phil Zarrow: Very good. Dr. Lee, thank you very, very much.
Dr. Ning-Cheng Lee: You're welcome.

Keywords: Phil Zarrow, Dr Lee, voiding, avoid the void, solder, solder joints, semiconductor, void mitigation, solder flux