Patent ID: 6121149
Filing Date: 2000-09-19
Classification: H01L

Abstract:
A method of forming a layer of an electrically conductive material filling at least one high aspect ratio recess formed in a surface of a workpiece, which method comprises the sequential steps of:forming a dielectric layer on a surface of a substrate comprising said workpiece, said dielectric layer comprising a first, lower portion of first thickness in contact with said substrate surface and a second, upper portion of second thickness on said first, lower portion; wherein the second, upper portion comprises a dielectric material having a greater lateral etch rate than said first, lower portion when subjected to a preselected etching process;forming at least one high aspect ratio recess in the exposed surface of said dielectric layer by said preselected etching process, said recess comprising:(a) a mouth surface portion at the upper end thereof comprising an opening having a width profile tapering from a first, wider width at said dielectric layer surface to a second, narrower width at a first depth below said dielectric layer surface substantially equal to said second thickness of said second, upper portion of said dielectric layer, said mouth surface portion bordering an adjacent, non-recessed portion of said dielectric layer surface;(b) an interior wall surface portion of said second, narrower width extending at a substantially constant width from said first depth to a second depth below said dielectric layer surface and terminating within said first, lower portion of said dielectric layer; and(c) a bottom surface portion at said second depth;forming an electrically conductive nucleation/seed layer over recess surface portions (a), (b), and (c), wherein formation of overhanging portions of said nucleation/seed layer at said mouth surface portion (a) is substantially prevented due to the first, wider width of said recess at the dielectric layer surface and the inwardly tapered width profile thereof;filling said recess with a layer of an electrically conductive material by electroplating said layer on the nucleation/seed layer over recess surface portions (a), (b), and (c);whereby at least one of occlusion and pinching off of the recess mouth surface portion (a) during said electroplating due to formation thereon of overhanging portions of said conductive material layer on overhanging portions of said nucleation/seed layer is prevented.