Stability of Embedded Solder Joints’ Electrical Resistance

This paper focuses on the electrical resistance’s stability of the embedded solder joints. Solder joints are an inseparable part of every printed circuit board, and the stability of its electrical properties is a key element of the reliability of printed circuit boards. This paper includes a comparison study of the electrical resistance’s stability of solder joints realized on the surface, and embedded solder joints. Three different solder pastes were used for this research (Sn96.5Ag3Cu0.5 SAC305, Sn96.5Ag3.5, and Sn89.2Ag3.5Bi0.5In6Cu0.8). The stability of electrical resistance was analyzed during the thermal shocks. The temperature range of thermal shocks was from $-45^{\circ} \mathrm{C}$ to $125^{\circ} \mathrm{C}$ and 1000 thermal shocks were realized. Measuring of electrical resistance was realized using the 4-point probe method (Milliohmmeter Agilent 4338B). The measurement of electrical resistance was realized before thermal shocks as well as after every 100 thermal shocks.