Using the Surface Potential Decay Method to probe electrical conduction in epoxy resins used for packaging

Abstract

ABSTRACTIn this work we discuss the usefulness of the Surface Potential Decay (SPD) method to investigate electrostatic charges deposited on epoxy resins which are used for electronic packaging. Corona discharges were applied on epoxy resins with different degrees of Post Mold Curing (PMC). SPD studies were conducted at room temperature under a relative humidity of about 45%. In the first part of this study we analyze the flow of electrostatic charges as a function of time. Using the SPD method we evidence that 10% of the electrical charge is still present at the surface three hours after the corona discharge has been applied. We find that the surface potential decay is more important for samples with longer PMC duration. In the second part of this work we provide a physical interpretation of the surface charge decay. We suggest that it is related to polarization mechanisms within the bulk of the material.