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Thread: General BGA package reliability questions

  1. #1

    Default General BGA package reliability questions

    The question therein may not belong in Non-flashlight Electronics, however I decided that it may be appropriate here as it wouldn't really pertain to the flashlight even though I am in the process of picking the parts for a prototype intelligent LED driver.

    Regarding shock impact from the flashlight or even the smartphone being dropped, how reliable is the BGA package? The reason I ask is because I am looking at Silicon Labs EFM32 Tiny Gecko microcontroller in PBGA-48 package so I can use all the analog to digital converter for sensor functions. Reliability takes priority here, obviously - serious enough to warrant swap out Quartz oscillator with MEMS oscillator (the brand of MEMS oscillator I use is SiTime, BTW), if I must use it.

    I also would like to hear about the experience of reliability and homemade electronic project using QFN and / or BGA packaged chips.
    ****** Custom filtered blacklight flashlight based on both Nichia NVSU233A-U365 and Convoy S2 flashlight host (Pictured in avatar icon) ******

  2. #2
    Flashaholic*
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    Pleasanton (Bay Area), CA, USA
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    Default Re: General BGA package reliability questions

    Surprisingly (at least to me) one of the most reliable packages even today for shock type applications are thu hole types. That is pretty limiting though.

    That being said, BGA is well regarded and the failure rates are fairly low. I have done some crude shock testing to compare various materials and methods in the past. While not as sophisticated as some the industry standardized tests, it seemed to work well enough to separate out good / bad / better. I would mount the parts and then test them by throwing them up in the air as high as I can and let them fall down on a concrete driveway. The heights reached were greater than 20 ft but I don't know just how high.

    Alternatively, I used to pitch baseball and would hurl them against a stone wall, sometimes at room temperature, sometimes fresh out of the freezer, and sometimes from a cooler with dry ice. I am guessing that the parts were traveling around 50 mph at impact.

    My own experience building DIY electronics (and I am not an expert at all) has been:
    - Cleaning matters more than just about anything else. I have had good luck with 90% pharmacy grade rubbing alcohol (such as from Target or similar)
    - Bonding and soldering materials with a little bit of flex outperformed more rigid materials that had higher mechanical specs
    - Potting the board with a flexible potting material helps immensely. In an ideal world, the adhesive should penetrate well underneath the package and board interface.
    - If you can, use lead based solder vs pure tin solder. I think (but cannot remember for sure) that Bi also helps.
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  3. #3
    Flashaholic
    Join Date
    Oct 2016
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    457

    Default Re: General BGA package reliability questions

    With rare exception for SMT, reducing mass increasing reliability w.r.t. shock.

    I would care more about the PCB flexing than the specific part package. That is usually the underlying failure mechanism.

    In general SMT is more reliable than through-hole.

  4. #4

    Default Re: General BGA package reliability questions

    Sorry about being absent for a while, I had to do something with life. I am back. The reason I asked is because some microcontrollers and sensors come in that package. However how you describe the failure mechanism regarding the circuit board is pretty much what I thought. So I think I will stick with QFN as there are plentiful of switchmode LED drivers using this type of package and I surmise the failure rate is a bit lower than with BGA package. That indeed cut the work out for me a bit but hey, I can work around it.
    ****** Custom filtered blacklight flashlight based on both Nichia NVSU233A-U365 and Convoy S2 flashlight host (Pictured in avatar icon) ******

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