Prevention of Cu Electrolytic Migration Defects on RDL by a Cu-Selective Passivation to Enhance Reliability

Copper (Cu) is the metal of choice for redistribution layer (RDL) to facilitate fast I/O communication in an integrated circuit (IC). Cu can electrochemically migrate (ECM) between array electrodes under bias, electrolyte, and moisture. IC packages fail miserably when exposed various ion impurities at anode dissolves form Cu+1, +2 ions. As anodic dissolution continues, concentration copper increases. These anions deposit on cathode leading dendrite formation. To achieve near zero ppb defectivity goal, elimination defects packaged devices critical. This work discusses development a novel Cu-selective passivation method accelerate reliability testing. A hydrophobic with minimum stress package proposed this work. The new coating thermally stable, strongly adheres Cu, corrosion resistant, low cost shows good potential prevent ECM defects. coated were tested by accelerated PEG drop test (PDT) explore its prevention capabilities.