Moisture absorption of molding compound and organic substrate

The moisture absorption experiments of 8 kinds of molding compound and two kinds of organic substrate at 30°C/60% RH was performed to evaluate the moisture absorption performance. Organic substrate absorbed more moisture than molding compound, which provides validation of baking process before die attach during assembly, and possible cause of inter-layer popcorn during ball attach or solder reflow of some laminated substrate device. Influence of resin type and filler content on moisture absorption of molding compound was analyzed. Occurrence of moisture in condensed state is assumed to be cause of non-Fickian diffusion of moisture, and simulation result with corrected diffusion coefficient showed good explanation to the experimental absorption curve.