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106 I-CONNECT007 I REAL TIME WITH... IPC APEX EXPO 2021 SHOW & TELL MAGAZINE other suppliers estimated a 5–15% yield loss and we think that there are opportunities to even improve that as well. In the long term, there are more advancements that need to be made to minimize layer-to-layer misregistra- tion such as better modeling of scale factors to improve prediction of movement of the layers during lamination. Another potential avenue is expanding the use of tack welding during layup to improve layer alignment. Holden: Were you limited to North American fabricators? IBM is worldwide so they could virtually use anybody in the world to examine? Czaplewski: Correct. We looked at several dif- ferent geographies. It was not limited to North America. ere were North American as well as Asian fabricators polled. Johnson: With that information, and what you learned from the testing, what's the payoff ? By effecting these sorts of changes, tightening the tolerances and making sure that you can deliver on them, what does that afford you as a design team? Czaplewski: Our recommendations were to move from five to four mil layer-to-layer mis- registration and reduce the antipad from 30 to 28 mils on a 10-mil finished PTH. e registra- tion aspect gives us about four to six percent improvement in signal-to-crosstalk ratio, and then the reduced antipad diameter aspect can provide about another seven to eleven percent improvement. at's the initial estimated ben- efit that we're receiving from it, and we'll be evaluating that with the specific designs as they become more mature. Johnson: Is there something about the research or about your research process that came as a surprise? Czaplewski: e great story here is that this was a cross-functional effort within IBM. It was brought together people from the signal integ- rity team, the hardware development team, and supply chain engineering team so that we can be more proactive about understanding our supplier capability and what we need for the next generation or products so that we can better deliver on the needs of our clients. Johnson: Sarah, have you submitted papers to IPC APEX before? Czaplewski: is was my first one to IPC APEX. Johnson: What was your experience like? Czaplewski: It's been good. It's been interesting because the conference was virtual this year instead of being in person. It was different to pre-record my presentation, but I think IPC has made the most of the virtual platform. Holden: You need to prepare something for next year so you can go to San Diego with the rest of us. Czaplewski: I'm in the second year of the Emerging Engineers program, actually. Last year was my first time at IPC APEX, and I got to go to San Diego; I have one more year in the program, so I will be there next year, for sure, and hopefully with another paper. Johnson: Sarah, thanks! Czaplewski: You're welcome. S&T