EVALUATION OF GAS CHEMISTRY EFFECTS ON WIRE BOND INTEGRITY AND PACKAGE INTERFACIAL ADHESION IN THE BGA PACKAGE
Author: Michael Leoni Company: Motorola Semiconductor Date Published: 11/1/2000
Abstract: This report includes results found in experiments evaluating several gas mixtures used for plasma cleaning at wafer and die level. Wafer level plasma is performed to clean contaminants off wafers after fabrication and shipment to assembly sites. Die level plasma is performed before wire bond for improved bondability to different pad metallizations and geometries. Analysis results will be presented showing which gas chemistry results in optimal cleaning of bond pads for optimized adhesion which reduces thermal sonic energy required to wire bond. Surface chemistry results are provided which show how the plasma gas mixtures effect various polyimides. This is correlated to interfacial adhesion performance of packaged parts subjected to elevated reflow temperatures and various JEDEC moisture sensitivity levels. And finally, a discussion of different mold compound properties and their effect on overall adhesion performance is also covered.