Corrosion of Aluminum Integrated Circuit Interconnect Passivated with Polyimide

Polyimides are among the most important class of polymers being considered for use as inner-layer dielectrics in multi-level metal systems or as organic passivation layers. These applications require that polyimides adhere well to the substrate and resist the diffusion of water. Deficiencies in these properties may result in corrosion of the underlying metal, often aluminum. Thus, we have studied the corrosion of Al test patterns under specific polyimides. Under the conditions of the test (85C, 85% RH, with electrical bias) the Al corroded readily.