Issue link: https://iconnect007.uberflip.com/i/1530610
16 PCB007 MAGAZINE I DECEMBER 2024 As technology advances, our substrates become increasingly smaller, and chip tech- nology has progressed to where HDI and UHDI are household terms. Ten years ago, this new design architecture would strike fear in the hearts of any plating engineer. Unfortu- nately, North American and European manu- facturing has lagged due to excessive offshor- ing of commercial and some high-reliability product lines. Fortunately, most of the mili- tary and aerospace product has remained con- trolled. But in doing so, the designs utilized by the mil/aero and medical sectors' reliabil- ity lines were corralled into the manufacturing capabilities of the North American and Euro- pean providers. is is changing with some of the more advanced PCB manufacturers now revamping lines and increasing capabilities to embrace HDI and UHDI substrates. One of the leading defect pareto bars has always been related to plating, specifically drilled holes and microvias. Plating anomalies in the via barrel or bonding in the microvias will, many times, not be detected during a stan- dard continuity test. resholds in the stan- dard electrical test adhere to manufacturing specifications such as IPC-9252, Requirements for Electrical Testing of Unpopulated Printed Boards. Continuity test requirements here are 10 ohms continuity for Class 3/C boards. e problem here is that minute changes in the copper thickness in a plated barrel or micro- via bond will not change to the extent that the 10-ohm continuity threshold will be violated. Feature Article by Todd Kolmodin GARDIEN SERVICES USA The Effects of Copper on a Transmission Line