Challenges and Impact of Surface Properties on Wafer-level Hybrid Bonding Process for Industrial Application

(23:14 + Q&A) Dr. Vikas Dubey, senior scientist, Fraunhofer ENAS
Presented at the 2026 IEEE Hybrid Bonding Symposium, Jan 21-22, 2026 in Silicon Valley.  More information below.

Summary: Wafer-level hybrid bonding is critical for achieving high-density 3D heterogeneous integration in advanced electronic packaging, meeting the industry’s rising demand for performance and miniaturization. However, successful industrial implementation relies on overcoming process sensitivities to surface topography, via pitch, dishing, roughness, chemistry, and contamination, which directly influence yield and reliability. This study investigates hybrid bonding from two industrially relevant perspectives: the impact of pattern pitch size and via depth on bondfront propagation, and the effect of dielectric type on bond uniformity and strength. Controlling bondfront speed is vital to ensure high bond strength while preventing voids, optimizing for robust mechanical and electrical properties across volume manufacturing. We systematically compare industrial-grade dielectrics (PECVD SiO2, SiON, SiN, ICP SiO) under varying surface treatments (RCA clean, N plasma, Ar plasma, O plasma) to identify process windows that balance throughput and defect minimisation. Preliminary results on aluminium integration as an interconnect alternative to copper are also presented, addressing CMOS compatibility of the process. Our findings deliver practical guidelines for scalable, reliable hybrid bonding processes, supporting industry efforts toward next-generation 3D integration and advanced packaging.
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Bio: Dr. Vikas Dubey is a senior scientist at Fraunhofer ENAS, where he has been contributing to the System Packaging department since 2021. With over a decade of experience in advanced system packaging, Dr. Dubey currently leads research initiatives in hybrid bonding, collective die-to-wafer bonding, and other wafer-level bonding technologies focused on MEMS/NEMS integration. In addition to his technical leadership, he is actively responsible for project acquisition and the management of both publicly funded and industrial projects in advanced system integration, hybrid wafer bonding, and assembly. Before joining Fraunhofer ENAS, Dr. Dubey served as Technology Manager at the National Nanofabrication Centre (NNFC) at the Indian Institute of Science, Bangalore. He also gained extensive experience at APTIV Services in Hungary, where he managed multiple Six Sigma projects that resulted in significant financial benefits, generating millions of euros in earnings. Dr. Dubey holds a PhD in Materials Engineering from KU Leuven, where he conducted his doctoral research at imec. His career is distinguished by a strong commitment to innovation in wafer-level packaging and system integration technologies, bridging academic research with industrial impact.

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