Vlsi device with global planarization

Abstract

A new method of fabricating an integrated circuit which maintains global planarization throughout the process flow is achieved. Trenched isolation regions are formed within a silicon substrate. Trenched polysilicon gate electrodes are formed within the silicon substrate and within the trenched isolation regions. Source and drain regions are formed within the silicon substrate wherein the top surfaces of the trenched isolation regions, the trenched polysilicon gate electrodes, and source and drain regions form a planarized top surface of the silicon substrate. A pre-metal dielectric layer is deposited over the planarized top surface. Contact openings are formed by etching through the dielectric to the trenched polysilicon gate electrodes and to the source and drain regions. The contact openings are filled with tungsten plugs wherein the top surfaces of the pre-metal dielectric and the tungsten plugs form a planarized top surface of the silicon substrate. A first metal layer is deposited over the planarized top surface. Oxygen ions are implanted into the first metal layer whereby the first metal layer is transformed into an insulator layer except where the layer is covered by photoresist wherein the top surface of the first metal layer forms a planarized top surface of the silicon substrate. The inter-metal dielectric layer and second metal layer are deposited, patterned, and planarized as for the pre-metal dielectric and first metal layers. A passivation layer completes fabrication of the integrated circuit.