Microvias allow signal and power transmission between layers in high density interconnection printed circuit boards. Presence of voiding in filled microvias due to defective manufacturing process has raised concerns in industry. Voids can vary widely in shape and size and have been observed in both stacked and single-level microvias. IPC standards have addressed the presence of voids in microvias using void size as the acceptance criterion. The purpose of this study is to determine how voiding affects the degradation of microvias; if void size is the only parameter that needs to be taken into consideration or void shape is important as well. Voided as well as non-voided microvias were tested using liquid-to-liquid thermal shock to understand the difference between behavior of voided and non-voided microvias under thermo-mechanical stresses.