Abstract: A semiconductor device includes a power transfer network layer on a lower surface of a substrate, a source/drain pattern being on the substrate, and including a first pattern and a second pattern spaced apart from each other in a first direction parallel to an upper surface of the substrate, a backside power rail extending along the first direction under the source/drain pattern, a backside conductive structure between the backside power rail and the first pattern of the source/drain pattern, an active contact on an upper surface of the second pattern of the source/drain pattern, a first interlayered insulating layer covering an upper surface of the source/drain pattern, and a conductive pad penetrating the first interlayered insulating layer along a direction vertical to the first direction, and connected to the backside power rail. The active contact is shifted from the first pattern of the source/drain pattern in the first direction.