RELIABILITY OF ELECTRICAL DEVICES DUE TO WARPAGE BEHAVIOR OF SMD-PACKAGES AND BOARDS DURING SOLDERING

摘要

Based on a government founded project there was implemented a test procedure for analyzing pcbs and SMD components because of warpage during reflow. Different and several components and pcbs has been analyzed by TherMoire-measurement and the results gave an indication for an internal stress after soldering. Especially an interaction in between components and pcb can have an negative effect, that means field failure or low untypically reliability results were implemented in this test. As an worst case scenario, a test pcb was created, the Warpage analyzed and there was also made reliability test (TCT) to see, what influence could have lead free alloys like SAC and Innolot, means are there improvements of reliability, although an initial stress will implemented by soldering. In summary the following points will be discussed: · Examples of components and pcb · Untypically reliability issue after stress (examples compared to standard) · Analyses by moire · FEM · Test Board and comparison results SAC and IL · Definition of limits · Discussion.