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

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 degreesC should be avoided. For a specified reliability goal, how to choose proper reflow time and temperature is discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.