A semiconductor device having a via chain circuit including a plurality of fine interconnections and an extension interconnection wider than the fine interconnections, having a first end connected to one or more of the fine interconnections and a second end located in an area of the semiconductor device external to the via chain circuit. One or more of the fine interconnections becomes wider gradually towards the connection to the extension interconnection. The extension interconnection is formed in a same layer as the one or more of the fine interconnections connected to the extension interconnection. The one or more of the fine interconnections connected to the extension interconnection is connected to the extension interconnections at a position where the fine interconnections become wider.