An integrated circuit device includes a wiring structure, first and second inter-wiring insulating layers, redistributions patterns and a cover insulating layer. The wiring structure includes wiring layers having a multilayer wiring structure and via plugs. The first inter-wiring insulating layer that surrounds the wiring structure on a substrate. The second inter-wiring insulating layer is on the first inter-wiring insulating layer, and redistribution via plugs are connected to the wiring structure through the second inter-wiring insulating layer. The redistribution patterns includes pad patterns and dummy patterns on the second inter-wiring insulating layer. Each patterns has a thickness greater than a thickness of each wiring layer. The cover insulating layer covers some of the redistribution patterns. The dummy patterns are in the form of lines that extend in a horizontal direction parallel to the substrate.