Issue link: https://iconnect007.uberflip.com/i/1525004
72 DESIGN007 MAGAZINE I AUGUST 2024 is manufacturing step involves a chemical deposition of copper. Specifically, it is a chem- ical-catalyzed deposition of copper, mainly to the epoxy inside the holes. Electroless differs from electrolytic in that electrolytic deposi- tion relies on electricity. However, there is too much insulating material in the different layers of the PCB for electrolytic processes to work in through-holes. Without electroless copper deposi- tion, boards later end up with voided copper holes in the manufacturing process. Understandably, this pre- paratory step is critical for the man- ufacturer to get right. When done correctly, it creates a very fine layer of copper that makes the connection from top to bottom through the through-hole. Since this thin layer of copper is conduc- tive, it allows a later electrolytic pro- cess to deposit a more thorough layer of copper. Preparing for Electroless Copper is step isn't simply spraying a bit of copper in the holes. It is a multi-chemical process that involves many chemical baths, rinses, and other processes. To prepare for this step, the manufac- turer first needs to clean up the residue le behind by the drilling process. Roll up your sleeves because it's time to get messy. In a recent episode of I-Connect007's On the Line with… podcast, we discussed elec- troless copper deposition. is process depos- its a copper layer into the through-holes and vias of what will eventually be a PCB. Electroless copper deposition feels like a black box to many people. It sort of looks like a black box, too. e boards go in one side, come out the other, and emerge differently. So, let's crack open that black box and look inside. Designing for Reality: Electroless Copper Connect the Dots by Matt Stevenson, ASC SUNSTONE CIRCUITS 72 DESIGN007 MAGAZINE I AUGUST 2024