Integrated circuit structure with thin dielectric between at least local interconnect level and first metal interconnect level, and process for making same

Abstract

An integrated circuit structure is provided with a local interconnect layer and a first metal interconnect layer which are both capable of bridging over underlying conductive regions. The structure comprises a first dielectric layer formed to a height or thickness equal to or preferably exceeding the height of the highest conductive regions of the underlying integrated circuit devices; a second dielectric layer formed above the first dielectric layer; one or more local interconnects formed in the second dielectric layer; and a thin third dielectric layer formed over the second dielectric layer and the local interconnects therein. The thin third dielectric layer has a thickness not exceeding about 2000 Å, and preferably ranging from about 1000 Å to about 1500 Å. A first layer of metal interconnects is formed over the thin third dielectric layer. Conventionally formed filled contact openings extend from the substrate through the first dielectric layer to either filled vias or a local interconnect in the second dielectric layer. The metal interconnects are electrically connected to either filled vias or one or more local interconnects in the second dielectric layer by filled shallow vias in the thin third dielectric layer. The shallow vias in the thin third dielectric layer are preferably filled with the same metals used to form the first layer of metal interconnects.