Influence of type of reflow technology and type of surface finish on tomb stone effect

Surface mount technology has many problems during production. One of them is a problem called tombstone effect. Tombstone effect is a well known phenomenon, when one end of the component (commonly small passive devices such as resistor or capacitor), rises up out of the solder pad and breaks conductive contact. It happens, when the solder alloy starts wetting earlier at the one end of the component. This article focus on the problem with tombstone effect, in concrete in this article we studied the influence of type of reflow technology and type of surface finish on tomb stone effect. In our experiments three types of reflow technologies (hot air soldering, IR soldering and vapor phase soldering), three sizes of SMD components (0805, 0603 and 0402), one type of solder paste Sn 96,5Ag3,0Cu 0,5 and three types of surface finishes (lead free H.A.L., passivated copper and ENIG) were used.