| abstract |
An apparatus includes an electronic component mounted on a substrate and metal conductors electrically connecting the electronic component. A conformal coating overlies the metal conductors and comprises a polymer into which a phosphine compound is impregnated and/or covalently bonded. Accordingly, the conformal coating is able to protect the metal conductors from corrosion caused by sulfur components (e.g., elemental sulfur, hydrogen sulfide, and/or sulfur oxides) in the air. That is, the phosphine compound in the polymer reacts with any corrosion inducing sulfur component in the air and prevents the sulfur component from reacting with the underlying metal conductors. Preferably, the phosphine compound in the polymer does not react with other components in the air (e.g., carbon dioxide) which would otherwise deplete its availability for the target reaction. The phosphine compound may be rendered completely non-volatile by covalently bonding it directly into the polymer backbone. |