Incorporation of dielectric layers in a semiconductor
First Claim
1. A process for forming a composite dielectric sandwich in an integrated circuit through the use of inorganic dielectric layers comprising the steps of:
- (a) forming a first inorganic dielectric layer over at least one underlying layer of said integrated circuit that has sufficient strength to protect said underlying layer by distributing stress from subsequently formed metal features that are deposited on said first inorganic dielectric layer;
(b) forming first metal features on said first inorganic dielectric layer;
(c) forming a polymer layer over said first inorganic dielectric layer and said first metal features of said integrated circuit, said polymer layer being substantially uniformly distributed to provide a substantially planarized surface;
(d) depositing a second inorganic dielectric layer in said integrated circuit over said polymer layer that provides sufficient strength to protect said polymer layer by distributing stress from subsequently formed second metal features that are deposited on said second inorganic dielectric layer;
(e) forming a mask on said second inorganic dielectric layer;
(f) etching said second inorganic dielectric layer using said mask as a masking pattern to form an inorganic dielectric mask and to provide a protective layer for etching of any subsequently deposited polymer layers;
(g) etching said polymer layer using said inorganic dielectric mask as a masking pattern to essentially remove all polymer unmasked by said inorganic dielectric mask between said inorganic dielectric mask and said first inorganic dielectric layer such that said first inorganic dielectric layer functions as a protective layer and etch stop for said underlying layers wherever said etching of said polymer layer continues after all of said unmasked polymer has been removed to fully expose any existing external contact surfaces of said first metal features;
(h) maintaining said second inorganic dielectric layer as an insulating layer that, together with said polymer layer, forms said composite dielectric sandwich that has sufficient strength to distribute stress from subsequently formed second metal features and that remains in said integrated circuit as an etch stop layer for subsequently formed layers in a multilayer integrated circuit;
(i) forming said second metal features on said second inorganic dielectric layer an in vias formed by etching said polymer layer.
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Accused Products
Abstract
A system for integrating a composite dielectric layer in an integrated circuit to facilitate fabrication of a high density multi-level interconnect with external contacts. The composite dielectric layer comprises of a polymer layer which normally comprises a polyimide that is deposited using conventional spin-deposit techniques to form a planarized surface for deposition of an inorganic layer typically comprising silicon dioxide or silicon nitride. The inorganic layer is etched using standard photoresist techniques to form an inorganic mask for etching the polymer layer. A previously deposited inorganic layer functions as an etch stop to allow long over etches to achieve full external contacts which, in turn, allows high density interconnect systems on multiple levels.
108 Citations
9 Claims
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1. A process for forming a composite dielectric sandwich in an integrated circuit through the use of inorganic dielectric layers comprising the steps of:
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(a) forming a first inorganic dielectric layer over at least one underlying layer of said integrated circuit that has sufficient strength to protect said underlying layer by distributing stress from subsequently formed metal features that are deposited on said first inorganic dielectric layer; (b) forming first metal features on said first inorganic dielectric layer; (c) forming a polymer layer over said first inorganic dielectric layer and said first metal features of said integrated circuit, said polymer layer being substantially uniformly distributed to provide a substantially planarized surface; (d) depositing a second inorganic dielectric layer in said integrated circuit over said polymer layer that provides sufficient strength to protect said polymer layer by distributing stress from subsequently formed second metal features that are deposited on said second inorganic dielectric layer; (e) forming a mask on said second inorganic dielectric layer; (f) etching said second inorganic dielectric layer using said mask as a masking pattern to form an inorganic dielectric mask and to provide a protective layer for etching of any subsequently deposited polymer layers; (g) etching said polymer layer using said inorganic dielectric mask as a masking pattern to essentially remove all polymer unmasked by said inorganic dielectric mask between said inorganic dielectric mask and said first inorganic dielectric layer such that said first inorganic dielectric layer functions as a protective layer and etch stop for said underlying layers wherever said etching of said polymer layer continues after all of said unmasked polymer has been removed to fully expose any existing external contact surfaces of said first metal features; (h) maintaining said second inorganic dielectric layer as an insulating layer that, together with said polymer layer, forms said composite dielectric sandwich that has sufficient strength to distribute stress from subsequently formed second metal features and that remains in said integrated circuit as an etch stop layer for subsequently formed layers in a multilayer integrated circuit; (i) forming said second metal features on said second inorganic dielectric layer an in vias formed by etching said polymer layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification