a gate structure on a substrate and including a gate electrode;

a gate contact connected to the gate electrode;

a source/drain pattern on a side surface of the gate electrode;

a source/drain contact connected to the source/drain pattern;

a first etching stop film structure on the source/drain contact and the gate structure, the first etching stop film structure including a first lower etching stop film and a silicon nitride film on the first lower etching stop film; and

a first via plug placed inside the first etching stop film structure and connected to the source/drain contact;

a second via plug in the first etching stop film structure and contacting an upper surface of the gate contact,

wherein the source/drain contact is between the source/drain pattern and the first via plug,

wherein the first lower etching stop film includes aluminum, and

wherein an upper surface of the silicon nitride film is on a same plane as an upper surface of the first via plug.