Metal wire of semiconductor device and manufacturing method of metal wire

The invention provides a metal wire of a semiconductor device and a manufacturing method of the metal wire. The manufacturing method of the metal wire comprises the following steps: providing a semiconductor structure of which the upper surface layer comprises an interlayer dielectric layer and a metal layer which are stacked in sequence; forming a buffer dielectric layer with a preset thickness on the upper surface of the metal layer, and forming a dielectric anti-reflection layer covering the upper surface of the buffer dielectric layer; forming a photoresist layer covering the upper surface of the dielectric anti-reflection layer, and patterning the photoresist layer; a groove penetrating through the dielectric anti-reflection layer, the buffer dielectric layer and the metal layer is formed based on the patterned photoresist layer, and the remaining part of the metal layer after the groove is formed serves as a metal wire; an isolation dielectric layer filling the trench is formed. According to the inventi