METAL-INSULATOR-METAL CAPACITOR IN COPPER

A parallel plate capacitor in copper technology is formed in an area that has no copper below it (within 0.3 mum) with a bottom etch stop layer, a composite bottom plate having an aluminum layer below a TiN layer, an oxide capacitor dielectric, and a top plate of TiN; in a process that involves etching the top plate to leave a capacitor area, etching the bottom plate to a larger bottom area having a margin on all sides; depositing an interlayer dielectric having a higher material quality below the top surface of the capacitor top plate; opening contact apertures to the top and bottom plates and to lower interconnect to a two step process that partially opens a nitride cap layer on the lower interconnect and the top plate while penetrating the nitride cap layer above the bottom plate, then cutting through the capacitor dielectric and finishing the penetration of the nitride cap layer.