Oxidation of copper leadframe

Delamination of the oxide film from copper alloy leadframes is considered a serious reliability problem for microelectronics packages. In an effort to identify the factors which may lead to the formation of brittle and/or poorly adhering oxides, kinetics of oxidation of leadframes in air was investigated by measuring the oxide thickness as a function of time at temperatures ranging from 200 to 300/spl deg/C. The oxidation was found to occur fairly rapidly in this temperature range. Analysis of the data indicates a logarithmic growth law in the 100-1400 nm thickness range, and an activation energy which is much smaller than that reported for the oxidation of unalloyed copper by a diffusion mechanism. The results of this investigation is presented here indicating the important role of defects in the oxidation of leadframe.