Abstract: A semiconductor device includes a first substrate having a first surface and a second opposite surface, a first lower interlayer insulating layer on the second surface, a first active pattern including a first lower pattern contacting the first surface, a plurality of first sheet patterns spaced apart from the first lower pattern in a second direction, a first gate structure on the first lower pattern, a first source/drain pattern on a side of the first gate structure, a second lower interlayer insulating layer including a third surface and a fourth opposite surface, a second active pattern including a second lower pattern contacting the third surface, a plurality of second sheet patterns spaced apart from the second lower pattern in the second direction, a second gate structure on the second lower pattern, wherein the first lower pattern has a first height, and the second lower pattern has a second different height.

Abstract: A driving device includes a motor, and first and second gears having gear teeth engaged with each other. At least one of the first gear and the second gear includes a crowning portion formed at a tooth surface of each of the gear teeth such that the center of the tooth surface is more convex than both ends of the tooth surface in a tooth width direction. A height of the crowning portion is determined to effectively compensate for misalignment between the first gear and the second gear.

Abstract: A driving device includes a motor, and first and second gears having gear teeth engaged with each other. At least one of the first gear and the second gear includes a crowning portion formed at a tooth surface of each of the gear teeth such that the center of the tooth surface is more convex than both ends of the tooth surface in a tooth width direction. A height of the crowning portion is determined to effectively compensate for misalignment between the first gear and the second gear.