Microwave Hybrid Heating (MHH) is a novel approach for material joining that is gaining attention due to its ability to achieve selective and uniform heating compared to conventional methods. In this experimental study, we prepared and characterized Sn-3.0Ag-0.5Cu nanoparticles. We investigated the interface morphology, phase composition, and mechanical properties of joints fabricated using the nano-Sn-3.0Ag-0.5Cu soldering paste and MHH technique with varying exposure times. Additionally, a reliability assessment was performed on these joints. This research investigated the impact of varying exposure times, ranging from 165 s to 420 s, on both the microstructure and strength of the joints. The joints were successfully produced under conditions of 900 W and 195 s using the MHH technique. Analysis was conducted to assess the joint morphology and mechanical properties of the after undergoing thermal shock tests, aiming to assess the reliability of joints manufactured through the MHH technique. The experimental findings revealed that the shear strength attained its peak value of 44.8 MPa when subjected to a microwave power of 900 W and an exposure time of 195 s. Moreover, the shear strength of MHH joints exhibited a 24.4% decrease after 1200 thermal shocks. Fracture analysis consistently indicated ductile fracture during thermal shocks, with no alteration in fracture mode observed.