Copolymer of Pyrrole and 1,4-Butanediol Diglycidyl as an Efficient Additive Leveler for Through-Hole Copper Electroplating

Electroplated Copper Additives for Advanced Packaging: A Review

Acid copper electroplating stands as a core technology in advanced packaging processes, facilitating the realization of metal interconnects, bumps, vias, and substrate wiring between transistors. The deposition quality of copper interconnect materials has a crucial impact on the final performance of chips, directly influencing their yield, reliability, and stability. In this intricate process, additives play a pivotal role in regulating the deposition quality and behavior of metal copper. This mini-review comprehensively summarizes the recent research progress in the field of electroplating copper additives for advanced packaging, both domestically and internationally, delving into the types and mechanisms of various additive molecules, including accelerators, inhibitors, and leveling agents. Through in-depth research on these additives, we gain a profound understanding of their specific roles in the electroplating process and the intricate interaction mechanisms among them, providing theoretical support for optimizing the electroplating process. Furthermore, this mini-review also delves into a thorough analysis of the current issues and challenges facing acid copper electroplating, exploring the key factors that constrain the further development of electroplating copper technology. Based on this analysis, we propose several potential solutions and research directions, offering crucial references for the development and application of electroplating copper additives in advanced packaging. In conclusion, this mini-review aims to provide a comprehensive perspective and profound understanding of the development and application of electroplating copper additives through a review and analysis of recent research progress, ultimately aiming to promote the further advancement of advanced packaging technology.

Influence of PUB2 on the Leveling Effect of Chip Copper Connection Electroplating: Mechanism and Applications

The copper connectivity technique is essential for achieving electrical interconnection in wafer level packaging (WLP), system in packaging (SiP), and 3D packaging. The essential processing material for copper connectivity is a copper sulfate electroplating solution in which organic additives play a crucial role in the regularity of copper electrodeposition. In this study, electrochemical tests, X-ray diffraction, 3D profiling, and scanning electron microscopy were used to investigate the leveling effect and mechanism of polyquaternary ammonium urea-containing polymer (PUB2) in the process of copper electrodeposition on-chip copper connections. PUB2 has excellent polarization ability on the target surface, remains unaffected by the sulfur additive SPS and poly(ethylene glycol), and displays a strong ability to regulate the copper deposition rate of through-holes and surface wiring. The waviness of the wafer surface wiring was reduced from 130 to approximately 70 nm after optimizing the PUB2 concentration, and the surface roughness was reduced from 10 to approximately 7 nm. The coating was dispersed evenly, and the rate of through-hole filling was improved by 57%. This study not only examined PUB2 leveling performance and mechanisms but also devised a research method and system for electroplating additives to facilitate the development and application of new electroplating additives.