Study of the effect of reflow time and temperature on Cu-Sn intermetallic compound layer reliability

Abstract In terms of various reflow time and temperature, an analysis of Cu–Sn intermetallic compound (IMC) layer reliability is presented in this paper. Temperature cycling test data reported in existing publications for the solder paste material of 63Sn/37Pb eutectic alloy is used to model the probability distribution functions of solder joint lifetime due to the IMC layer fatigue. The relationship of the IMC layer thickness as a function of reflow time and temperature is studied. A reliability and mean time to failure function of the IMC layer in terms of various reflow time and temperature are presented. Calculation suggests that to achieve a higher IMC layer reliability, a shorter reflow time and a lower reflow temperature should be used, while lowering reflow temperature may be more efficient than controlling reflow time. In general, a reflow temperature ranged by 240–280 °C should be avoided. For a specified reliability goal, how to choose proper reflow time and temperature is discussed.