Patent ID: 6265780
Filing Date: 2001-07-24
Classification: H01L

Abstract:
A dual damascene structure for electrically interconnection to a base metal interconnect structure formed in a semiconductor substrate, which comprises:a first dielectric layer formed from a low-K inorganic dielectric material selected from a group consisting essentially of silicon dioxide, fluorosilicate glass, fluorosilicate oxide, and hydrogen silsesquioxane, over the substrate to cover the exposed surface of the base metal interconnect structure;an etch-stop layer formed from a low-K organic dielectric material selected from a group consisting essentially of Flare, SILK, benzocyclobutene (BCB) and Parylene, over the first dielectric layer; a second dielectric layer formed from a second low-K inorganic dielectric material selected from a group consisting essentially of silicon dioxide, fluorosilicate glass, fluorosilicate oxide, and hydrogen silsesquioxane, over the etch-stop layer;a protective layer formed between the etch-stop layer and the second dielectric layer, wherein the dielectric constant K of the protective layer and the dielectric constant K of the etch-stop layer are different; anda pair of metal plugs including a first metal plug and a second metal plug, the first metal plug penetrating through the second dielectric layer, the protective layer, the etch-stop layer, and the first dielectric layer to come into electrical contact with the base metal interconnect structure in the substrate, and the second metal plug penetrating through the second dielectric layer and the protective layer to come into contact with the etch-stop layer; anda hard mask layer formed over the second dielectric layer, wherein the protective layer includes an inorganic dielectric material selected from a group consisting essentially of silicon oxide, silicon-oxy-nitride and silicon-nitride.