RBS measurement of the thickness of nanometer oxide layers: Adhesion strength between copper leadframe and molding compound correlated with the oxide layer thickness

The thickness of the oxide layer on a copper die pad strongly influences the adhesion to the molding compound in an electronic device, and is an important parameter for the device reliability. We directly measured the oxide layer thickness between leadframe and molding compound using Rutherford backscattering spectroscopy and correlated these values with the adhesion strength in pull tests. We also examined the oxidation during post mold curing.