Should Intermetallic Thickness Measurements Be Needed To Determine Solder Joint Reliability
Authors: Scott K Buttars, Chonglun Fan, and Raiyo F. Aspandiar Company: Intel Corporation Date Published: 10/31/2012
Abstract: The presence of Intermetallic Compound (IMC) at the solder-to-land interfaces of a solder joint is one of the attributes used to indicate proper formation of a solder joint. Detecting and measuring IMC thickness requires cross-sectioning and is difficult, time consuming and destroys the sample. There is a desire to correlate IMC thickness to various surface mount processes and to characterize the solder joints acceptability to reduce failure analysis efforts. Experiments were designed to determine the IMC thicknesses after various board assembly processes and to correlate this to solder joint reliability. This paper describes these designed experiments using boards with an Organic Surface Preservative (OSP) surface finish and the ranges of IMC thicknesses generated by various reflow and rework process conditions. Factors that contribute to the growth of IMC will be discussed, reliability data from thermal cycling and shock are covered and recommendation for future socket programs is given.