Issue link: https://iconnect007.uberflip.com/i/1529411
36 PCB007 MAGAZINE I NOVEMBER 2024 Over the past several months, we have received a lot of questions from our customers about cupric chloride etching—mostly about how to improve etch quality, but also about process problems. Most of them were easily dealt with, but the questions arose because the people involved in running the etching process were not aware of the finer nuances involved in using cupric chloride as the primary etchant. (ey don't have courses on etching in most colleges and trade schools.) I thought this might be a good time to summarize some things I have learned in my 50 years of experi- ence with cupric chloride etching and clear up some of the confusion. When I started in the industry (1974), the mantra was speed, speed, speed. e main goal was the ability to process as many square feet of product as possible in the shortest amount of time. State-of-the-art was 10-mil (250 µm) lines and spaces and double-sided panels, so etch quality was not of prime importance. e etched lines just had to carry the proper amount of current with enough space between them to prevent shorts and crosstalk. Chem- istry-wise, the best etch rate was attained at Getting the Best from Your Cupric Chloride Etchant The Chemical Connection by Don Ball, CHEMCUT