COMPARISON OF SURFACE MOUNT YIELDS FOR TIN-BISMUTH LOW TEMPERATURE SOLDER VS. SAC IN AN AGGRESSIVE MOTHERBOARD DESIGN

摘要

As the consumer electronics industry begins to assess the feasibility of converting from Tin-Silver-Copper (SAC) solder pastes to lower melting point Tin-Bismuth (Sn-Bi) based solders for electronics manufacturing, questions of cost and reliability must be analyzed to inform the decision. One key variable in understanding cost and reliability performance is the component yields and resulting solder joint quality of the Surface Mount Technology (SMT) process. If overall SMT yields decline when implementing low temperature solders, cost advantages gained with lower electricity usage and reduced BGA package warpage could be partially or fully off-set. In this paper, component yield results will be compared between SAC and Sn-Bi solder pastes for a functional motherboard design using aggressive printed circuit board (PCB) design rules. In addition, information will be included regarding any Bill of Materials (BOM), PCB design, or manufacturing set-up changes that were necessary to enable the conversion from SAC to Sn-Bi solder paste.