Issue link: https://iconnect007.uberflip.com/i/1509873
26 PCB007 MAGAZINE I OCTOBER 2023 Much of our current focus is on the U.S. CHIPS Act, and for the future of PCB fab- rication and assembly, this is appropriate. I started my career in manufacturing thin-film RF (sapphire) substrates, as well as conven- tional multilayers and HDI. I have researched and built IC substrates for the past 50 years. I know we depend on the technologies that trickle down from semiconductor and RF substrates. Panel size is an important aspect of PCB productivity, yields, and cost. If a fabricator or assembler can process larger panels, then their productivity increases and their cost per board drops—provided that yields are not affected. Yields are an important process parameter, as they affect all costs and performance mea- sures; they are driven by defect density, and that affects considerations of larger panel siz- ing. Defect density is not oen talked about in PCB fabrication, unlike wafer processing, where it is a driving factor. e Poisson Model is used as the defect den- sity model to predict yields in semiconductor fabrication. I use the reciprocal of this equa- tion to calculate a PCB's first pass yield: FPY = 100/exp[(log CI/A)^B] 1 Where: FPY = first-pass yield (%) CI = PCB complexity index A, B = Fabrication capability coefficients Large Panel Processing Happy's Tech Talk #23 by Happy Holden, I-CONNECT007