An insufficient bond between copper layers can lead to electrical test failure.
Delamination of printed circuit boards is typically associated with large blisters or bubbles in the board after soldering, but there are different examples of this phenomenon. The examples in FIGUREs 1a and b show via popping after reflow soldering, also known as “copper via rivet.”
In the images, the through via has elongated as the board expanded during heating. As layers in the multilayer board delaminated, further strain was placed on the copper plating until failure occurred. The board did fail electrical test, but the only problem visible on the surface of the board was the cracking of the solder mask, which can clearly be seen.
Quality is a must. Endless inspections are not.
I sometimes get this overwhelming feeling some things are heading backward. Some of that could be age, but regrettably there are times and situations decidedly not related to age, but highlighted by the experiences that have made me age.
Such is the trend currently taking place of customers who insist on verification and validation protocols that seem to accomplish only one thing: increasing the headcount at any and every company that supplies that verification and validation-gone-crazy customer.
Don’t get me wrong. I am all for producing quality product. Earlier in my career I was with a company whose owner early on embraced TQM (Total Quality Management) and all that went with it. The lessons of Deming, Shingo and the concepts of Kaizen, FMEA, value stream mapping, poka-yoke, Kanban, and Lean became our obsession. The result: reducing staff by 25% – mostly by attrition – while increasing sales 30%, mostly via shorter lead times and better quality. Oh, and costs went down too, way down. Yes, two of our organization’s three goals were delivering quality on time. Third and most important, however, was delivering maximum value to customers so we could be more competitive and, therefore, secure increased levels of business from existing and new customers. Continually improving quality and service required an organization to be Lean, efficient, and to reduce unnecessary and non-value-add processes.
For years I’ve resisted the calls (and occasional) urge to expand our vehicles for delivering information to voice or video. There are a number of reasons why.
For one, I felt – and still feel – a large percentage of our subscribers actually like the activity of reading. (After all, you are reading this, right?) This has been borne out by the fact that we maintain a subscriber base of more than 60,000 designers and engineers. That’s a lot of eyeballs, and it doesn’t begin to take into account the thousands and thousands more who aren’t subscribers and read the magazine online.
I also recognize that for many in our industry, work is all-consuming. Seriously, when outside the office, how often do you check your email, or log in to see how your factory is running? Frequently, I imagine. The tools that allow us to physically escape the office have the ironic capability to keep us tethered to it. Health experts advise that when you have a chance to disconnect, you should take it and not look back. Easier said than done.
I sat with Irene Sterian at the SMTAI technical committee recognition dinner in September. (As an aside, if you’ve never had the pleasure of speaking with Irene, you really should find the time. She could make rubber chicken seem interesting.) Amid conversation on IoT, islands of St. Bernards, Quebec City, Elon Musk and cats, we got to talking about disruptive technology.
It was one of those conversations where you completely abandon the good manners your mother taught you, as you keep interrupting the other party out of excitement about the topic.
To be clear, I believe “disruption” is often an inflated term. Most of what we call disruptive is really just “painful to a certain segment of people or business.” Take ride-sharing, for instance. Type in “Uber” or “Lyft” and “disruptive,” and a Google search returns a combined 850,000 results. But what have those businesses truly changed? We still use what is essentially 100-year-old technology – cars – to get from Point A to Point B. Ride-sharing may have altered the value of the municipal taxi, but it certainly did not change the transportation industry.
Picking the right tool for electrochemical contamination at the rework bench.
A half-dozen versions of the same scenario occurred in the past month, all having to do with materials and processes used in post-op/rework applications. This step of the production process often escapes the attention of engineers because there’s no cool machinery or any real engineering that takes place. Most hand-solder operators are highly proficient and have developed techniques that get the job done, which can lull a supervisor or production manager into a false sense of security. Electrochemical contamination doesn’t normally appear until it has become a dreaded field failure. In fact, if the issue is contamination/corrosion/leakage-related, the first place I look is the rework bench, and eight times out of 10 that’s where the trouble spots lie.
Manual soldering applications have different requirements than upstream processes, and it’s worth detailing these differences to understand the importance of materials selection and proper usage.