Issue link: https://iconnect007.uberflip.com/i/1536435
24 PCB007 MAGAZINE I JUNE 2025 butes ("prettiness") of sections from a few via structures, some are also floated on a solder pot before microsectioning. We are meant to believe those few floated via struc- tures will demonstrate the PCB's ability to survive the component attachment process. While a single wave solder process may have been the norm many years ago, we now pri- marily attach components with convection reflow. Today's component attachment pro- cess may also include replacement of compo- nents, attachment of connectors, and hand soldering of various parts and wires, which ultimately exposes the PCB to several solder- ing temperature cycles before truly begin- ning its life in the field. is is something that is not being captured in today's solder float and microsection process. e cost and time necessary to evaluate the prettiness of two points on a few via structures exposed to a single wave solder simulation have begun to out- weigh the value received for the effort, which heralds the eventual slow death of the microsection for assessing PCB qual- ity and reliability. We've held on to the micro- section for so long, and it's so ingrained in our industry that it's hard to bury it. Still, the truth is that a small sampling of prettiness does not directly equate to PCB via structure quality and reliability. e microsection will always have a place in failure analysis and R&D, but its usefulness for evaluating the quality, reli- ability, and robustness of today's via structures is almost at an end. Yet, until recently, we haven't had much of an alternative. As is always the case, need has driven the high reliability sector of the electron- ics industry to create a methodology for expos- ing daisy-chains of PCB via structures (IPC "D" coupons) to multiple simulated convection reflow cycles while monitoring the electrical integrity of the structures. is is subsequently followed by 100 cycles of thermal shock. is more than 24-hour process gives an understanding of the PCB's ability to survive the convection reflow component attachment process and whether early reliability issues will arise in the field aer assembly. A lot less faith is required when you can empirically demonstrate solder process survivability and some level of reliability cycling on hundreds of via structures from a production panel. In anticipation of the slow and painful death of the microsection, I have spent the past several years developing the HATS2 test system, which performs convection reflow simulation and rapid thermal shock cycling on multiple IPC daisy-chain coupons at once. I encourage you to read my recent interview with Barry Matties, which goes into detail. So, don't fret about the death of the micro- section. As is so oen the case, when one window closes, a door opens. e death of the microsection makes way for the birth of a methodology that empirically and directly evaluates via structure quality, reliability, robustness, and convection reflow process survivability to help you improve your build. PCB007 Bob Neves is chair and CTO of Reliability Assessment Solutions Inc. Bob Neves " As is so oen the case, when one window closes, a door opens. "