Method of etching aluminium-based layer

摘要

An Al-based metal layer (10) is formed on the semiconductor body (11) and then coated with a layer (25) of photoresist. A resist pattern is then formed in the layer (25) of photoresist by means of lithography. The resulting semiconductor substrate (21) is placed in the reaction chamber of ICP (Inductively Coupled Plasma) equipment. A mixed gas containing HCl and BCl3 is introduced into the reaction chamber to etch the metal layer (10) using the photoresist layer (25) as a mask, thereby forming interconnect lines. The etching is effected by Cl ions or Cl active species disassociated from either HCl or BCl3. In this etch process, the Cl ions or Cl active species react with the photoresist to thereby form a sidewall protection film (26) consisting of Al2O3 at sidewalls of the lines of interconnect. <IMAGE>