EVALUATION OF THE WARPAGE BEHAVIOR OF SMD-PACKAGES AND PRINTED CIRCUIT BOARDS DURING SOLDERING

摘要

The coplanarity between the printed circuit board or substrate and the SMD-package is a very important characteristic. This coplanarity depends on the warpage of board and package. An insufficient coplanarity can lead to open solder joints and/or shorts between solder joints. Additional mechanical stress especially in z-direction inside the solder joints may also occur. The warpage of packages and boards changes during a soldering process. TherMoire and an in-situ X-Ray measurements give the possibility to examine the warpage under soldering conditions. The IPC-bow and -twist as well as an adapted coplanarity are characteristics to evaluate the warpage of printed circuit boards. New limits for an acceptable warpage behavior during soldering will be offered. The paper presents first results of the public funded research project (WARPAGE_ZUV) at the Technische Universitat Dresden.