Contact structure for reducing gate resistance and method of making the same

摘要

A semiconductor device having a gate on a substrate with source/drain (S/D) regions adjacent to the gate. A first dielectric layer overlays the gate and the S/D regions, the first dielectric layer having first contact holes over the S/D regions with first contact plugs formed of a first material and the first contact plugs coupled to respective S/D regions. A second dielectric layer overlays the first dielectric layer and the first contact plugs. A second contact hole formed in the first and second dielectric layers is filled with a second contact plug formed of a second material. The second contact plug is coupled to the gate and interconnect structures formed in the second dielectric layer, the interconnect structures coupled to the first contact plugs. The second material is different from the first material, and the second material has an electrical resistance lower than that of the first material.

主权项

1. A semiconductor device, comprising:
a gate structure on a semiconductor substrate; source/drain regions laterally adjacent to the gate structure in the semiconductor substrate; a first dielectric layer overlying the gate structure and the source/drain regions, wherein the first dielectric layer has first contact holes over the source/drain regions; first contact plugs formed of a first conductive material filling the first contact holes, wherein the first contact plugs are electrically coupled to the respective source/drain regions; a second dielectric layer overlaying the first dielectric layer and the first contact plugs; a second contact hold formed in the first and the second dielectric layers; a second contact plug formed of a second conductive material filling the second contact hole at least in the first dielectric layer, wherein the second contact plug is electrically coupled to the gate structure; and interconnect structures formed substantially in the second dielectric layer, the interconnect structures electrically couple to the first contact plugs; wherein the second conductive material is different from the first conductive material, and the second conductive material has an electrical resistance lower than that of the first conductive material; wherein the second contact hole and the second contact plug formed of the second conductive material extend continuously from the first dielectric layer to the second dielectric layer.