Features Articles

Mike Buetow

FPGAs are a multibillion-dollar business, characterized by suppliers like Xilinx, MicroChip, Texas Instruments and Cypress Semiconductor. So why are they reliant on a single source for copper-wrapped solder column attachment?

And not just any source. Six Sigma is a small, founder-run Silicon Valley-based company. For more than 30 years, it has performed a variety of third-party services, including solder dipping, BGA reballing, and solderability testing. It also happens to be the sole supplier of copper-wrapped solder column attachment services to the major FPGA vendors. And according to industry watchers, that leaves the supply chain in something of a pickle.

The risk with any sole source is something happens that affects their ability to make deliveries. Such an outcome would spell disaster for the high-rel companies that use column grid arrays (CGAs). And loss of access to the unique copper-wrapped columns used in key programs, including military and space, would put those applications at severe risk.

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Peter Bigelow

As veteran engineers know, sometimes less is more, and a lot faster.

Our industry is noted for spectacular new technology that eclipses everything around it at breathtaking speed. As exciting and noteworthy as those technologies may seem, however, success more often moves in ways and at speeds akin to the proverbial turtle. Patience pays.

The virtue of patience struck me while attending a regional industry event. The afternoon included technical presentations and a tour of an advanced manufacturing facility. The tour was conducted by energetic, sharp, intelligent young engineers who were excited and proud to show off the fruits of their labors. The facility did not have the latest equipment, but these innovative young bucks set up the equipment to take full advantage of the latest in holistic ergonomic advances, lean material logistics, and had a connected digital ecosystem that would make any Industry 4.0 proponent proud.

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Greg Papandrew

Automation and faster amortization should mean lower costs.

PCB manufacturers often include nonrecurring engineering (NRE) and electrical test (ET) charges in quotes, in addition to the piece price. During my training sessions for board buyers, I am frequently asked how to avoid those charges.

It’s a good question.

When I started in this industry some – ahem – 30 years ago, NRE charges were approximately $100 per conductive layer, meaning a 4-layer PCB was $400; a 6-layer PCB was $600, and so on. Back then, it took a lot of labor hours to create manufacturing files from a piece of original artwork, as nothing was as digital as it is today.

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Bob Willis

Measuring BGA joints can reveal process problems.

This month we show variation in the size of the solder joints on a section of a BGA. Measuring variation on solder ball size after reflow is useful. Even better is when measurements are taken automatically with an x-ray system, as this provides a good comparison tool between NPI and production builds.

Measuring NPI build, and saving the measurement data, provides a good point of reference when problems are seen on a build. It is also useful when moving between contractors or in the event of changes due to other process modifications.


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Sue Mucha

Workers need to understand the “why” of manufacturing and how to manage processes.

The pace of technological change continues to increase. Products are getting smaller and more challenging to build. The increased levels of automation needed to build those products are driving a need to rethink the role of the personnel associated with those machines. The worker who fills those new jobs needs to understand the “why” of manufacturing and have the critical thinking skills to manage processes rather than just run machines.

One example of this role rethinking is happening at Burton Industries, an electronics manufacturing services (EMS) provider whose primary manufacturing facility is in Michigan’s Upper Peninsula.

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Clive Ashmore

Achieving printing nirvana is largely dependent on solder paste material, print speed and deposit release.

Ahhhhh … screen printing utopia. We process engineers strive for this existence. In a perfect process, printed solder paste would emerge from the stencil as exact replicas of the aperture shape: nice, flat, brick-like deposits. And, while modern printers and advanced materials get us close, solder paste is still, well, solder paste. The materials are not inks; they have a grain structure that is getting smaller in size and distribution and is suspended in flux. Try as we might, with these particles, there will be material undulation at best, and flat paste surfaces will likely never be a certainty.

With printing, we must be pragmatic. It’s not a digital process, and many variables come into play. The goal, of course, is to fill all the apertures on the stencil fully with solder paste to obtain the best deposit shape and volume possible. This is easier said than done, as the range of aperture sizes across a stencil can be broad, with 1mm square, 300µm and 200µm openings next to one another. Each of those apertures – from the very large to the very small – must be filled. Since printing with different thickness stencils is a nonstarter (generally and practically speaking), compromise is required, and that challenges our utopian ideal. Squeegee pressure, stencil thickness, print speed and separation speed must be balanced to accommodate variations in required deposit sizes. When all inputs aren’t optimized and in perfect balance, solder deposit shape differences can have the potential to introduce process problems. Known in the printing world as “dog ears” on square or rectangular deposits and “witch hats” on circular deposits (FIGURE 1), these solder paste deposit peaks may be defect bugbears, especially in the world of high-density, miniaturized assemblies.

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