IMPROVING THE PCB ASSEMBLY MANUFACTURING PROCESS BY UTILIZING AN ALTERNATIVE SOLDER PASTE: A STATISTICAL EVALUATION

摘要

To address the requirements of component miniaturization, high-density board designs and ever-increasing throughput and yield, solder paste technology is evolving. Not only must next-generation solder materials offer meaningful improvements in process performance, but also provide more manufacturing flexibility by expanding the process window. The ability to effectively accommodate manufacturing environments where assembly processes are interrupted, where the luxury of long start-up times are nonexistent and where materials are often handled non-optimally, materials capabilities in the modern age of manufacturing are critical. Results from an investigation that studied and characterized a novel lead-free solder paste as compared to traditional solder materials will be presented. As basis for the analysis, solder materials were exposed to harsh environments to understand if the new solder paste technology is capable of withstanding the realities of modern manufacturing processes for fine pitch components (0.3 mm CSPs and 01005/0201 passives). Evaluation of solder paste printing performance was a primary focus of the investigation, taking into consideration numerous common board finishes and stencil aperture designs. Paste volume measurements acquired by SPI were used to verify solder paste volume on pads to quantify performance. Challenging manufacturing processes were simulated by aging the pastes at room versus elevated temperatures and then printing at defined time intervals. Simulated extended continuous printing was also examined. A detailed statistical analysis identifies the relationship between the condition of the solder paste and the paste volume on the pad of a given component type.