US Patent 11764149 Semiconductor device

A semiconductor device includes transistors on a substrate, a first interlayer insulating layer on the transistors, a lower interconnection line in an upper portion of the first interlayer insulating layer, an etch stop layer on the first interlayer insulating layer and the lower interconnection line, a second interlayer insulating layer on the etch stop layer, an upper interconnection line in the second interlayer insulating layer, the upper interconnection line including a via portion penetrating the etch stop layer to contact the lower interconnection line, and an etch stop pattern on the etch stop layer and in contact with a first sidewall of the via portion. The second interlayer insulating layer extends on the etch stop pattern and a top surface of the etch stop layer free of the etch stop pattern. A dielectric constant of the etch stop pattern is higher than a dielectric constant of the etch stop layer.