A method of forming a contact in an integrated circuit between a first
metalization layer and a silicon substrate. In one embodiment the method
comprises forming a premetal dielectric layer over the silicon substrate,
etching a contact hole through the premetal dielectric layer and then
forming a thin silicon nitride layer on an outer surface of the contact
hole. The silicon nitride layer reduces overetching that may otherwise
occur when oxidation build-up is removed from the silicon interface within
the contact hole by a preclean process. After the preclean process, the
contact hole is then filled with one or more conductive materials. In
various embodiments the silicon nitride layer is formed by exposing the
contact hole to a nitrogen plasma, depositing the layer by a chemical
vapor deposition process and depositing the layer by an atomic layer
deposition process. In other embodiments, the method is applicable to the
formation of vias through intermetal dielectric layers.