A FLUORINE-RELATED PASSIVATION LAYER ON ETCHED AL-CU (1-PERCENT) ALLOY SURFACES ON SILICON AFTER SF6 PLASMA TREATMENTS

After etching AI-Cu alloy films on Si using a SiCl4/Cl-2/He/CHF3 plasm a, a corrosion phenomenon on the metal surface was studied. In the AI- Cu alloy system, corrosion occurs rapidly on the etched surface by res idual chlorine atoms. To prevent the corrosion, an SF6 plasma treatmen t subsequent to etching has been carried out. A passivation layer is f ormed by fluorine-related compounds on the etched AL-Cu surface after the SF6 treatment, and the layer effectively suppresses the corrosion on the surface as the SF6 treatment pressure increases. The corrosion could be successfully suppressed with the SF6 treatment at a total pre ssure of 300 mTorr. (C) 1998 Elsevier Science B.V. All rights reserved .