Issue link: https://iconnect007.uberflip.com/i/1050827
62 PCB007 MAGAZINE I NOVEMBER 2018 Interview by Barry Matties and Happy Holden I-CONNECT007 Dock Brown of DfR Solutions gave a key- note speech at SMTAI, "Requirements for Both Cleaning and Coating to Building Medi- cal Hardware." Barry Matties and Happy Hold- en sat down with Dock to discuss the current trends he sees in failure analysis, the concept of "rules versus tools," and how predictive en- gineering software used early in the design cy- cle can help predict failures in components and microvias and drive cost down. Barry Matties: Dock, can you just tell us a little bit about what DfR Solutions does? Dock Brown: DfR Solutions is an international reliability consulting firm. There are basically three aspects to the technical portion of our business. We do 1,200–1,300 failure analyses a year. The value proposition that we offer to our clients is that we have a whole suite of on- staff Ph.D. material science folks. These peo- ple are experts in chemistry, physics, and met- als. What we try to do first is to understand the customer's problem because most of the time, they don't just want a quick cross-section in a picture—they want us to get to the root cause of the root cause of the root cause. We first try to thoroughly understand the problem or set of problems the customer is fac- ing, and then when we acquire the samples, we treat those very gingerly. We make sure that we have damaged and exemplary sam- ple because oftentimes, you want to do an A/B comparison between the two. Then, we do a very careful disassembly or cross-section; we do non-destructive kinds of things first. Usu- ally, you can see the issue there, and even if you can't see the problem non-destructively, it will help you focus in on it. For example, if you have a 600-ball ball grid array (BGA) with an issue, we can't afford to cross-section every single one of those little guys; we have to fo- cus on the ones that are most likely to be prob- lematic. Once we get down to the failure in the BGA ball, where is that fracture occurring—is it in the metallization or the ball itself, or is it even a pad cratering kind of issue? The second part of our business is that we sell a software package called Sherlock that does reliability physics analysis. We're apply- ing mathematical modeling to all the various complex material structures that are involved in any kind of electronics applications. You have, in the case of a circuit board, polymers, metals, ceramics, etc. All of these materials Dock Brown on Succeeding at Failure Analysis