An interconnection is provided with a dummy interconnection connected to an interconnection body, and the dummy interconnection is provided with a stress concentration portion in which tensile stress higher than that of the interconnection body is generated. In proximity to the stress concentration portion, an insulating film formed by high-density plasma CVD is provided, and the tensile stress is generated in the stress concentration portion by the insulating film. With this structure, the occurrence of a void can be prevented at any position in the interconnection body.