Computational Corrosion Analysis for Design of Microelectronic Components Under Conditions of Atmospheric Corrosion

摘要

The PWB's of current combat system electronics experience a variety of in-service and environmental situations owing to thermal cycling, shock loading, and humid atmospheres. Temperature cycling in a humid environment provides the condensation conditions necessary for atmospheric (thin-film) corrosion of the components of the boards and also causes deflections sufficient to crack conformal coatings or disbond them from the solder joints. This results in corrosion of surface components and diffusion of moisture into the porous dielectric layers, allowing corrosion and electrodeposition between copper film conducting layers. Numerical corrosion analysis capability is extended to applications of thin electrolytes (atmospheric condensates) on multimetallic and multipotential electronic components. Dissolution or electrodeposition rates are predicted for the metal components on printed wiring boards. Guidelines for printed wiring board spatial design are projected from the results of these analyses. Keywords: Computational corrosion analysis; Corrosion; Electronic components; Electronic packing; Finite element analysis. (kt)