A method for fabricating semiconductor device includes the steps of first forming a first inter-metal dielectric (IMD) layer on a substrate, patterning the first IMD layer to form first IMD patterns on the substrate, a trench surrounding the first IMD patterns, and a second IMD pattern surrounding the trench, forming a metal layer in the trench to surround the first IMD patterns, forming a second IMD layer on the first IMD patterns, the metal layer, and the second IMD pattern, and forming via conductors in the second IMD layer. Preferably, the via conductors not overlapping the first IMD patterns.