Cleaning method of etching cavity

The invention provides a method for cleaning an etching cavity, which comprises the following steps of: providing an etching machine table and a wafer group comprising a plurality of wafers, selecting N wafers, forming metal interconnection structures on the wafers, and enabling the etching cavity in the etching machine table to comprise an electrostatic chuck which is provided with a plurality of air holes; sequentially fixing the first wafer to the (N-1) th wafer to the electrostatic chuck for etching, introducing first cleaning gas into the etching cavity in a time period between etching of the two wafers, and forming a first plasma cleaning etching cavity by ionization of the first cleaning gas; and the Nth wafer is moved to the electrostatic chuck for etching, then first cleaning gas is introduced into the etching cavity, and first plasma is formed by ionization of the first cleaning gas to clean the etching cavity. According to the invention, gas causing damage to the electrostatic chuck in wafer-free a