Forming wide dielectric-filled planarized isolation trenches in semiconductors

A process for forming a wide dielectric filled isolation trench in the surface of a semi-conductor substrate comprising the steps of: forming a wide trench in the surface of the substrate; conformally forming a layer of dielectric material on the surface of the substrate including in said trench the top surface of which layer of dielectric material extends above the plane of the surface of the substrate; conformally forming a layer of etch resistant material on said layer of dielectric material which etch resistant material will mask said dielectric material from reactive ion etching; selectively removing only those portions of said etch resistant material that extend above the surface of the dielectric material by physical polishing and not removing any etch resistant material disposed below the surface of said dielectric material, such that the only remaining portion of the etch resistant material resides within the width of said trench; forming a dielectric plug above said trench by anisotropically reactive ion etching said layer of dielectric material which is not masked by said etch resisting material down to the top of said trench; and removing said dielectric plug to obtain a dielectric-filled trench having an upper surface in substantial planarity with the upper surface of said substrate.

A process for forming a filled wide trench in the surface of a substrate comprising the steps of: forming a wide trench in the surface of the substrate; conformally forming a layer of filling material on the surface of the substrate including in said trench the top surface of which filling material extends above the plane of the surface of the substrate; conformally forming a layer of etch-resistant material on said layer of filling material which etch resistant material will mask said filling material from reactive ion etching; selectively removing only those portions of said etch resistant material that extend above the surface of the filling material by physical polishing and not removing any etch resistant material disposed below the surface of said filling material, such that the only remaining portion of the etch resistant material resides within the width of said trench; forming a plug above said trench by anisotropically etching said layer of filling material which is not masked by said etch resisting material down to the top of said trench; and removing said plug to obtain a filled trench having an upper surface in substantial planarity with the upper surface of said substrate.