Solder wire die bond technology is well established and widely used in high power microelectronics devices. A growing market in semiconductors is expected with high demand especially from the automotive sector. Accordingly, the demand for an improvement in product quality is also expected to grow with more reliable and better manufacturability. Solder joints' long-term reliability is an ultimate requirement for electronics packaging. Solder joint reliability under normal operating conditions is usually influenced by its geometric properties: the bondline thickness, the adhesion strength, voids under the die-attach layer and the material's mechanical properties also affect the joint behaviour. The solder joint failure mechanism is very complex. One of the many basic failure processes in this technology is solder thermal fatigue, This paper presents the interactions between equipment critical parameters, solder alloys composition and the metallization of the substrates that affect the solder wire bond characteristics. The solder alloy's characteristics under study include 65% Sn 25% Ag 10% Sb (J-Alloy), 95% Pb 2.5% In 2.5% Ag, 95.5% Pb 2.5% Ag 2% Sn, and 95% Pb 5% Sn. The substrate metallization is plated with Nickel and Silver. Many people believe that, to avoid solder thermal fatigue failure in high power devices operating under thermal cycling test, we need to achieve a minimum of 1 mils bondline thickness between die backmetal and substrates metallization. However, the phenomenon is not applicable in this device under study. In addition, the reliability results also proved that the minimum of 1 mils bondline solder thickness is not a must to have a reliable solder joint structure.