Issue link: https://iconnect007.uberflip.com/i/1535414
30 PCB007 MAGAZINE I MAY 2025 Reducing Defects in Circuit Board Production We all agree that in any manufacturing pro- cess, reducing defects in your product induced during manufacture (aka increasing yields) is a good thing. Doing so, however, can be a source of contention and frustration. I don't pretend to be an expert in this field, because most of my work involves feasibility studies for new con- cepts or testing improvements made to exist- ing equipment. High yields were usually not a factor; it's simply about having enough data to prove or disprove a concept or seeing whether improvements to equipment design actually work. However, here are some observations I made visiting quality shops where high produc- tion at high yields was important. I witnessed The Chemical Connection Feature Column by Don Ball, CHEMCUT common steps they all used in their campaigns to reduce defects and increase yields. e first thing most shops did was study the process steps in the production line—from incoming materials to outgoing packaging— and how to optimize each step. During the etching process, they looked in detail at sur- face preparation, etch resists, resist applica- tion, phototools, resist exposure, develop- ing, and etching. By this, I mean they analyzed roller temperatures for dry film lamination, exposure times and intensities, developer con- centrations, etc., to determine the most effi- cient and cost-effective ways to produce their high-density circuits.