Just Ask Happy: Monitoring Via Reliability on a Lot-by-Lot Basis

I-Connect007 Editorial Team | 07-29-2020

We asked for you to send in your questions for Happy Holden, and you took us up on it! The questions you've posed run the gamut by covering technology, the worldwide fab market, and everything in between. Enjoy.

Q: What is the best way to monitor microvia reliability on a lot-by-lot basis for high-volume production?

A: What I recommend, and practice, is this: Do a thorough qualification of a fabricator using a HATS Qualification Panel (an IPC PCQRR-like panel) that includes an IPC D coupon resized for the runner on your SMT panel. Run these panel coupons through IPC-TM-650-2.6.27B and then TM-650-2.6.7.2 thermal cycles for 500 cycles. This is your baseline.

Then, by incorporating this smaller D coupon on all your boards’ assembly runners—requiring each lot to have a plating process control coupon for X number of solder float tests at 288°C and then microsections to look at TH quality—you have a way of comparing that lot’s performance to your initial qualification for that vendor. This should be redone each year and kept for records on each lot in case needed later.

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