Effect of multiple reflow cycles on intermetallic compound creation

This paper deals with the effect of the solder profile and multiple reflow cycles on intermetallic compound (IMC) creation. Soldered joints between PCB and 1206 size chip resistors were made from SAC 305 or SnBi solder alloy. Samples were reflowed one to six times with one of the two different soldering profiles for each soldering alloys. The thickness and composition of IMC layers were measured and observed with a scanning electron microscope. The growing of IMC layers thickness was observed. The results are presented depending on greater value of heating factor and number of reflow cycles. The shear forces for the components were measured and the fracture interfaces were inspected.