Issue link: https://iconnect007.uberflip.com/i/1426508
40 DESIGN007 MAGAZINE I NOVEMBER 2021 they can improve the yield by some amount, and they have less product coming back as a field return. at's one way to do cost justifica- tion. I don't know if that totally answers your question, but it's a discussion that we have and we've been able to lead EMS providers to see the light with that type of a discussion, whereas an OEM is typically easier. ey have an easier time understanding that they're going to get a benefit from DFT and test strategy simulation right away. Johnson: Is there a point where an EMS com- pany can require this pre-work of their cus- tomer? Webb: Yes. We've seen them say, "We don't want to accept the board design to build, unless it's been qualified." If proper DFT and test coverage analysis hasn't been done, then they know that's going to cause them trouble, it's going to cause their engineers more time, and it's going to be a more difficult product for them to build. ey may not necessarily be able to charge more money to their customer, just because it's more difficult for them to build. Andy Shaughnessy: How does that soware work? Webb: Essentially, the TestWay tool allows you to close the feedback loop from your design clear through your manufacturing and pro- duction phase. In the old days, the designers operated in a silo. ey would oen throw the design over to the test engineers when they were done with routing/layout. Test engineers then reviewed the design, and maybe found some potential issues and possible improve- ments. However, in many cases it was too late to fix these problems. ere was no continuous feedback loop built into the process. TestWay allows you to quickly analyze the design, even early in pre-layout phase, and give feedback to the board designers about what they could do with the design to make it more testable, and where you need (or don't need) the test points because, perhaps, you're going to test that cir- cuitry with some other method. en as you go into manufacturing, you can extract and examine the failure data. And you can have a better understanding of your DPMO. It can help you the next time you look at designs so that you're continually driving improvement. Now, rather than test operating just at one point, you have a nice, continuous feedback loop clear from the design through DFT, test strategy estimation, test program creation, test program measurements, and even field returns. Because you need to under- stand what your field returns are, you can ask, "Are we getting these back because we're miss- ing some test coverage? Is there some test cov- erage that's really not where it should be?" at helps you get better and drive improvement. Johnson: Where should a soware tool like this be utilized? Because both parties, OEM and EMS, benefit from this. Webb: at's right. It's something we've thought about and refined so we could have those discussions when an EMS provider or William Webb