As lead-free solders gain prominence in electronic packaging, Sn-Cu lead-free solder has emerged as a focal point due to its commendable performance and cost-effectiveness. Relative to Sn-Pb solders, Sn-Cu variants exhibit a higher melting point. In this study, zinc alloys are explored as an alternative alloy. The investigation employs the Micro Vickers Hardness test alongside comprehensive analysis of intermetallic compounds (IMC) and microstructures using an optical microscope. The Micro Vickers Hardness test evaluates the solder’s resistance to indentation, offering quantitative insights into its hardness. Examination of IMC aims to discern the bonding nature between the added zinc alloy and the base Sn0.7Cu solder. This scrutiny extends to microstructural observations, leveraging the optical microscope to examine solder details. The study’s findings deepen our understanding of how the introduction of zinc alloy impacts the mechanical properties and microstructural attributes of Sn0.7Cu solder. Sn0.7Cu samples, infused with zinc additions of 0.2%, 0.4%, and 0.6%, undergo a reflow process at 200 ℃ before hardness testing, IMC and microstructure analysis. Results indicate that increased zinc addition correlates with heightened hardness, refined microstructure, and reduced growth layer of IMC. Such insights are pivotal for refining solder formulations, ensuring superior performance in practical applications, and advancing soldering technology.