Method of filling of contact openings and vias by self-extrusion of overlying compressively stressed matal layer

A process for filling openings in an insulating layer on an integrated circuit structure with metal to provide an electrical connection between one or more structures beneath the insulating layer and one or more metal contacts above the insulating layer which comprises:

• (a) forming over an integrated circuit structure a layer of insulating material having one or more openings therein extending from an upper surface of said insulating layer to said integrated circuit structure underlying said insulating layer;
• (b) forming a barrier layer over said insulating layer and exposed surfaces within said one or more openings;
• (c) forming over said barrier layer and over the top of said one or more openings therein a metal layer formed with a compressive stress level which will permit said metal layer to extrude into said openings when said metal layer is subsequently heated;
• (d) then forming, over said metal layer, previously formed with a compressive stress level, a capping layer of a tensile stressed material having a tensile strength which will prevent said metal layer from extruding upwardly when said metal layer is subsequently heated whereby compressive stress is formed in said metal layer prior to forming said capping layer;
• and
• (e) then heating said structure to a temperature which will permit said metal layer to extrude into said one or more openings to completely fill said one or more openings in said insulating layer with metal from said metal layer.

In the formation of integrated circuit structures, a process for filling with metal openings in an insulating layer formed over underlying integrated circuit structure using a metal layer initially formed over said insulation layer which comprises:

• (a) providing an insulating layer having one or more openings therethrough;
• (b) forming a compressively stressed metal layer over said insulation layer having a thickness which will cover said one or more openings therein;
• (c) then forming a capping layer over said compressively stressed metal layer, previously formed, said capping layer having a tensile strength level which will resist upward movement of said compressively stressed metal layer during subsequent heating of the structure whereby compressive stress is formed in said compressively stressed metal layer prior to forming said capping layer;
• and
• (d) subsequently heating said structure to a temperature which will cause said compressively stressed metal layer to extrude into and fill said one or more openings without, however, melting said compressively stressed metal layer.