Inspired by mortise–tenon structure: 3D interlocking design for direct Cu bonding of cu arrays without solder

The mortise-tenon structure, a quintessential technique in traditional Chinese carpentry, achieves robust jointing through the precise interlocking of convex and concave components without nails or adhesives. Inspired by this “interlocking via concavo-convex geometry” principle, this study explores the feasibility of realizing direct Cu bonding for Cu arrays through 3D structural design, eliminating the need for solder. Using a one-step selective electrodeposition process, Cu pillar arrays and Cu dendritic arrays were fabricated. The study systematically investigates the effects of thermocompression bonding and cold pressure bonding on the bonding performance of joints, revealing the intrinsic relationship between bonding processes and microstructural interlocking mechanisms. This low-temperature interconnection method, with an operational temperature range of 100–250 °C, based on 3D mechanical interlocking and free from solder, presents an innovative solution for high-density, high-reliability packaging of power electronic devices. It highlights the potential of integrating traditional craftsmanship’s wisdom with modern micro–nanomanufacturing technologies to enable direct Cu bonding without intermediate phases.