Experimental Verification of Water Ingress in a Void by Quick Diffusion at High Reflow Temperature Available to Purchase

The pop-corning failure is known to result from high vapor pressure generation inside cavities at defective interfaces of the electronic package. In order to study the phenomenon, vapor pressure inside a void at high temperature is measured using a specific specimen configuration developed for this purpose. The specimen incorporates a volume-controllable cavity at a polymer-metal interface. A pressure sensor is used to monitor pressure evolution inside the void at high temperature. An underfill material used in the configuration is characterized in terms of hygroscopic properties. The phenomenon is also simulated on a finite element model based on these properties and specimen geometry. The prediction by the numerical model well matches the measurement by pressure sensor. This corroborates the validity of the hypothesis of high vapor pressure employed in numerous existing studies that simulated the pop-corning failure.