Transient Thermal Analysis of Wave Soldering Process for an Optical Encoder Module

摘要

Severe delamination at the interfaces of leadframe/mold compound and leadframe/die attach epoxy has been observed right after the wave soldering process for an optical encoder package. During wave soldering process, package is heated up by the hot ambient and the molten solder. As temperature increases, package is more prone to delamination due to degradation of adhesion strength. Finite Element Analysis (FEA) has been conducted to model the wave soldering process using the measured lead temperature as thermal boundary condition. Convective heating and cooling are considered. The dynamic temperature response of the package has been captured and analyzed. Several approaches inclusive of changing leadframe material, removing housing and altering mounting configuration, have been examined to obtain the best design that yield lowest package temperature. Experiment is conducted and the experimental results have been compared with the numerically predicted data and the agreement is good.