Galvanic corrosion behavior of Ag-filled electrically conductive adhesive on Sn-plated of surface mount chip resistor

The present paper investigated the corrosion behavior of electrically conductive adhesives (ECAs) on tin (Sn)-plated surface mount chip resistors with epoxy mold compound (EMC)in integrated circuit (IC) packaging. Test samples were assembled by a chip resistor with Tin plating outer terminal attached by Ag-filled electrically conductive adhesive then encapsulated by EMC. Three stimulants temperature, moisture and electrical bias were applied during reliability testing (Moisture Sensitivity Level, Temperature Humidity Bias, Unbiased Highly Accelerated Stress Test ) to accelerate galvanic corrosion. As long as no delamination after MSL was observed, no tin corrosion/oxidation was observed after THB and UHST. The resistance value after UHST 400hrs was comparable with unstressed samples. The overall results show that galvanic corrosion could be avoided by assembling the product without any internal delamination. Currently, IC packaging uses optimized process parameters and state of the art materials which increase product robustness (no delamination) avoiding the formatting of local electrolytes that enables the migration of ions from higher to lower electron potential, causing corrosion