Digital Twin Concept in Copper Electroplating Process Performance

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Editor’s Note: This is an excerpt from a technical paper presented at the inaugural Pan European Design Conference in January 2025. It is reflected as originally presented with minor edits for grammar. There is a link to access the full paper at the conclusion of this excerpt.

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 on the outer layers. The purpose of the process is to provide a uniform distribution of copper across the outer layers to make the plating current density 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 up front 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.

To read the entire paper, which appeared in the June 2025 issue of PCB007 Magazine, click here.