Formation of a thin oxide protection layer at poly sidewall and area

Abstract

A new method for forming polysilicon lines using a SiON anti-reflective coating during photolithography wherein a thin oxide protection layer is formed over the polysilicon sidewalls and active area surfaces after etching to prevent damage caused by removal of the SiON in the fabrication of integrated circuits is achieved. A gate oxide layer is provided on the surface of a silicon substrate. A polysilicon layer is deposited overlying the gate oxide layer. A SiON anti-reflective coating layer is deposited overlying the polysilicon layer. A photoresist mask is formed over the SiON anti-reflective coating layer. The SiON anti-reflective coating layer, polysilicon layer, and gate oxide layer are etched away where they are not covered by the photoresist mask to form polysilicon lines. The polysilicon lines and the silicon substrate are oxidized to form a protective oxide layer on the sidewalls of the polysilicon lines and on the surface of the silicon substrate. The SiON anti-reflective coating layer is removed wherein the protective oxide layer protects the polysilicon lines and the silicon substrate from damage to complete fabrication of polysilicon lines in the manufacture of an integrated circuit device.