Integrated circuit devices including metal wires and methods of forming the same

An integrated circuit device comprising:

• a first insulating layer and a second insulating layer that are sequentially stacked;
• a lower etch stop layer extending between the first insulating layer and the second insulating layer;
• and
• a plurality of metal wires on the first insulating layer and in the second insulating layer, the plurality of metal wires comprising a first metal wire and a second metal wire,
• wherein the lower etch stop layer extends on a sidewall of the first metal wire from a lower surface to an upper surface of the first metal wire, and the second metal wire extends through the lower etch stop layer.

A method of forming an integrated circuit device, the method comprising:

• forming a first metal wire on a first insulating layer, the first metal wire comprising a first lower surface that faces the first insulating layer;
• forming a second insulating layer on the first metal wire and the first insulating layer;
• forming an opening extending through the second insulating layer;
• and
• forming a second metal wire in the opening, the second metal wire comprising a second lower surface that faces the first insulating layer and is coplanar with the first lower surface.