Electrodeposition Fabrication and Mechanical Properties Study of Ag-Zn Solid Solution Films

Ag-Zn exhibits an exceptionally high post-yield plastic deformation capacity, making it a key material for low-temperature, low-pressure solid-state bonding in electronic packaging. Solid-state bonding normally requires metal films thicker than 5 μm to provide enough deformability. Electrodeposition is the preferred method to deposit such films onto chip micro-bumps. We investigated the Ag-Zn electrodeposition process using electrochemical polarization theory. By adjusting bath composition and deposition parameters, we fabricated Ag-Zn films containing 13.83 wt.% Zn. High-resolution STEM analysis revealed Guinier-Preston (GP) zones enriched in Zn within the Ag matrix. Compared with pure Ag films, the Ag-Zn solid-solution coatings showed substantially improved compressive plastic deformability, enabling reliable solid-state bonding of micro-bumps at low pressures.