Interaction of metal with underlying dielectric films in multilevel interconnect systems

The authors report the interaction of an aluminium film with its underlying LPCVD dielectric film. The LPCVD film absorbs moisture in the atmospheric environment and causes severe degradation in subsequently deposited metal films. The addition of phosphorus appears to have two competing effects: enhancement of water absorption and densification of the film. The authors have identified deposition temperature, plasma power density, and ion bombardment as parameters for improving dielectric film stability. Modifying the oxide network by doping the glass and/or providing energy during oxide deposition improves the dielectric integrity, and this type of stable dielectric film is very essential for a multilevel interconnect system.<>