Etching method of metal wire

The invention provides a metal wire etching method which is applicable on a plasma etching device which is provided with an etching cavity and a tripping cavity. A holder platform for placing a wafer and a lifting and supporting mechanism for lifting and supporting the wafer are arranged inside the stripping cavity. In prior art, the wafer is placed on the holder platform all the time during the process of stripping the optical resistor, so active chlorine at the surface of the wafer is not totally removed, which results in erosion to the metal wire. In the method of the invention, chlorine is firstly fed into the etching cavity to etch the wafer; then the etched wafer is placed on the holder platform and the stripping cavity is heated until the temperature reaches the preset temperature; after that, the stripping cavity is driven to a stable state and the wafer is passivated for the first time; the optical resistor is stripped; the stripping chamber is driven to a stable state and the wafer is passivated for