An integrated circuit device includes a double-humped protrusion protruding from a surface of an inter-device isolation region. To manufacture the integrated circuit device, a plurality of grooves are formed in the inter-device isolation region of a substrate, a recess is formed by partially removing a surface of the substrate between the plurality of grooves, at least one fin-type active area is formed in a device region by etching the substrate in the device region and the inter-device isolation region, and the double-humped protrusion is formed from the surface of the substrate in the inter-device isolation region.