Advancing Electrolytic Copper Plating for AI-driven Package Substrates

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Editor’s note: The following technical paper, originally titled “Cutting-Edge Pulse Plating Solutions for Uniform Deposition of Copper with Enhanced Reliability in State-of-the-Art Server Technology,” was first presented at IPC APEX EXPO 2025’s Technical Conference, with original work published within the conference proceedings.

The rise of artificial intelligence (AI) applications has become a pivotal force driving growth in the server industry. Its challenging requirements for high-frequency and high-density computing are leading to an increasing demand for development of advanced manufacturing methods of package substrates with finer features, higher hole densities, and denser interconnects. These requirements are essential for modern multilayer board (MLB) designs, which play a critical role in AI hardware. However, these intricate designs introduce considerable manufacturing complexities.

The Critical Role of Electrolytic Copper Plating

Electrolytic copper plating is a key process in package substrate manufacturing, significantly impacting subsequent stages such as etching. A major challenge in electrolytic plating is ensuring uniform copper distribution across the entire panel, whether in areas with a high density of holes or more isolated sections. Such high hole-density regions are integral to modern multilayer board (MLB) designs, despite introducing several manufacturing complexities. Traditional plating methods often result in inconsistent copper thickness across regions with varying hole densities, leading to discrepancies known as the “surface thickness gap.” This can lead to inconsistencies in etching and overall circuit performance. Moreover, achieving high throwing power is crucial to ensure sufficient copper is deposited within through-holes without excessive surface copper.

To continue reading this article, which originally appeared in the July 2025 issue of PCB007 Magazine, click here.