Etchback and desmear serve many purposes. The first purpose of etchback is to assure the copper is clean. Assuring the copper is clean will then help form a metallurgical bond with the plating. The last purpose of etchback is to form a three-point contact around the inner layer. Why are each of these processes so important? Below we will go in more depth as to how each process effects the overall goal of etchback.
Flexible circuits were first introduced as a replacement for wire harnesses. The earliest versions date back to World War II. Today, flex and rigid flex circuits are filling an important role across multiple industries, include applications in the medical, automotive, and telecom fields.
Today we are being asked by OEMs, particularly in the high-frequency space, for ways to minimize the amount of surface roughness to provide for enhanced electrical properties. Of course, when you minimize roughness you also run the risk of compromising the optimum adhesion of the smoothed material – especially if you don’t do any surface prep.