Case Analysis on PTH Fracture Caused by Twin Copper

Abstract

An actual case of PTH fracture after soldering process was studied. By means of cross section analysis using metallography microscope and SEM, together with thermal analysis results, root cause of PTH fracture was concluded that a high density of twin copper weakened the mechanical strength so seriously that PTHs could not undergo thermal stress from soldering process, and higher CTE was attributed to an accelerative factor. Moreover, it is recommended to enhance current density properly and make sure the effectiveness of electroplating additives to prevent twin copper by theoretical analysis.