a semiconductor device is made up of a first insulating layer having a through hole ; a first interconnection which comprises a first conductive layer , a first barrier layer , and a first main interconnection , and a second interconnection connected to one of the first conductive layer and the first barrier layer . accordingly , the semiconductor device can avoid a problem so that the cu of the first main interconnection transfers from a portion connected to the second interconnection due to cause electromigration , the connected portion becomes a void , and the first interconnection is disconnected to the second interconnection .