Microchip with cap layer for redistribution circuitry and method of manufacturing the same

Abstract

A microchip includes a passivation layer formed over underlying circuitry, a redistribution layer formed over the passivation layer, and a cap layer formed over the redistribution conductors of the redistribution layer and in contact with the passivation layer. The passivation layer and the cap layer have one or more compatibilities that provide sufficient adhesion between those two layers to prevent metal migration from the conductors of the redistribution layer between the interfaces of the passivation and cap layers. In one embodiment, the passivation and cap layers are each formed from an inorganic oxide (e.g., SiO) using a process (e.g., PECVD) that provides substantially-uniform step coverage by the cap layer in trench and via regions of underlying circuitry. The invention increases the reliability of the microchip, because it eliminates metal migration, and the electrical shorting caused therefrom, in the redistribution layer.