Fine Pitch Wafer-to-Wafer Hybrid Bonding for Three-Dimensional Integration

Abstract

As the demand for advanced semiconductor packaging technology continues to rise, achieving precise control of the wafer bonding process becomes increasingly critical for optimal performance. This research paper focuses on the development of a fine-pitch hybrid wafer bonding technique specifically designed for heterogeneous integration applications. The objective is to enable high-density interconnections and enhance electrical performance through the bonding of Cu and SiO 2 wafers featuring 15μm spaced Cu pads. The experimental section provides a comprehensive account of the study, covering various aspects such as layout design, preparation, and the bonding process. This includes the fabrication of Cu pads and SiO 2 passivation layers, chemical mechanical polishing (CMP), and alignment bonding. Furthermore, the research also investigates Cu-Cu die-to-die bonding utilizing a (100)-oriented single-crystal Cu top die paired with a Si substrate. Microstructure analysis demonstrates a well-fused bonding interface characterized by a highly preferred (100)-oriented Cu film. The insights obtained from this study contribute to the advancement of wafer-level hybrid bonding techniques for three-dimensional integration technology. This research serves as a valuable contribution to the ongoing development and refinement of advanced semiconductor packaging methods.