A method of forming an interconnect structure for an integrated circuit device is provided. The method includes forming a conductive line layer over a semiconductor substrate. The conductive line layer includes a metal line. The method also includes forming a conductive pillar on and in contact with the metal line. The method further includes depositing a dielectric layer over the conductive line layer to cover the conductive pillar, and etching the dielectric layer to form a trench. The conductive pillar is exposed through the trench. In addition, the method includes filling the trench with a conductive material to form a conductive line.