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76 DESIGN007 MAGAZINE I JULY 2020 pitch—here's some kind of an RS232 connector, and here's some memory. We invented a way to connect these little cir- cuit board blocks together. Generally, it was well- received. But the problem we found was that people could no longer hand solder these parts onto the boards as they could a few years ago. When the pitch was a 1.27 millime- ter, they could do that, but when pitches started getting down to 0.65, 0.5, and 0.4, and they could no longer hand solder it. We asked ourselves, "Is there a way for us to make it where people could now solder these new parts the way they used to with older technology?" We worked for two years and went through many differ- ent ideas. We finally came up with the idea of significantly raising the solder mask, letting the parts fall in, and then the solder mask turns into walls in between the legs. It then became much easier to solder—even a 0.4-millimeter pitch IC—and the products quickly went into Fry's, Digi-Key, and Mouser and Arrow, for example. Today, our products are sold to a "who's who" of companies. Andrew Yaung: One of the hardest things for someone to do when hand soldering a surface- mount IC onto a PCB is to position the legs. We brought up the solder mask a little bit higher and ended up achieving two things during the process. One is that the chips then dropped into what we call canals, and second, the sol- der mask became protective barriers for shorts between each leg. If you were to look at the current product lines that do the prototyping for people with hand soldering, you would see canals—the traces are long so that they can use a soldering iron and push the solder through inside that canal. That was done on purpose so that they don't necessarily have to use outside solder, although if they use outside solder, it's better for them. We always thought that someday, eventu- ally, if this technology were to be polished, it could get much better usage. We started talk- ing to folks from the aerospace industry, such as Lockheed Martin and NASA. We discov- ered one of the biggest prob- lems that they have is these joints get broken in a very high-pressure and high-vibra- tion environment. The idea for using this technology is that, if you can imagine, each of those legs sits inside a pocket or a nest. Then, the whole leg will be covered with solder during the solder reflow pro- cess. This will make the joint not only stronger but also not crackable anymore. It's almost like a through-hole technology—and perhaps even better than through-hole—because the whole leg or nest is surrounded with solder. The idea that we are taking into the next phase is to have this be used in the volume production environ- ment for reliability purposes. The other thing that we also discovered was that during the manufacturing process today in high-volume products—because compo- nents are becoming smaller and smaller and smaller—when they go through the reflow oven, they have to bring up the temperature as high as possible and then cool it down by blowing air into it. During that process, many tiny components get shifted. That's why, in a production assembly line, you'll see a sepa- rate station called final inspection for boards. They're inspecting by eye whether a compo- nent gets shifted and which one they have to rework. This technology will also improve that. You can imagine that the component legs will be sitting inside the pocket so that it will not come up. That's the whole idea behind this. Dr. Ephraim Suhir, a Ph.D. who worked for Bell Laboratory, mathematically proved that this would be 10 times more reliable than the current way of doing things. Greenberg: This also works for things like QFN and BGA and any of the modern components. Neal Greenberg

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