The role of the digital twin concept in assessing and optimizing copper electroplating process performance (PEDC 2025)

Aga Franczak; Robrecht Belis, Elsyca NV.

Abstract

PCB manufacturing involves transforming a design into a physical board while meeting specific requirements. Understanding these design specifications is crucial, as they directly impact the PCB's fabrication process, performance, and yield rate. One key design specification is copper thieving - the addition of “dummy” pads across the surface that are plated along with the features designed onto the outer layers. The purpose of the process is to provide a uniform distribution of copper across the outer layers to make plating current and plating in the holes more uniform. Copper electroplating is crucial in PCB manufacturing, primarily because it reduces ground line impedance and voltage drop. The performance of the electroplating process directly affects the quality of the copper layer and related mechanical properties. In acid copper plating, achieving proper thickness distribution and surface uniformity without compromising metallurgical properties like elongation and tensile strength is challenging. Lowering the current density can help equalize copper thickness but significantly increases plating time, adversely affecting PCB throughput. Therefore, controlling process performance and the quality of the electroplated copper layer are vital aspects of PCB plating, which remains challenging even for experienced PCB manufacturers. Recognizing plating process performance in terms of copper layer coverage and thickness upfront adds significant value to process design and control. This paper explores the concept of automated copper thieving and the digital twin of the copper plating process in PCB manufacturing. These modern CAE tools facilitate the rapid assessment and mitigation of copper under- and over-plated surface areas, aligning closely with the principles of smart manufacturing.