The novel improvement of low dielectric constant methylsilsesquioxane by N2O plasma treatment

The organic silsesquioxane, methylsilsesquioxane (MSQ), has a low dielectri c constant because of its lower film density compared to thermal oxide. How ever. the quality of MSQ film is degraded by the damage of oxygen plasma an d hygroscopic behavior during photoresist stripping. In this work, we studi ed the N2O plasma treatment for improving the quality of MSQ. The leakage c urrent of MSQ decreases as the N2O plasma treatment time is increased. The dielectric constant of N2O plasma-treated sample remains constant (similar to 2.7). In addition, the thermal stability of MSQ film can be enhanced. Th e role of N2O plasma is to convert the surface layer of organic MSQ into in organic type by decomposition of the alkyl group and thus form a passivatio n layer. The inert passivation layer enhances the resistance to moisture up take and O-2 plasma attack. Therefore, N2O plasma-treatment greatly improve s the quality of low k MSQ film and removes the issue of photoresist stripp ing in the integrated process. (C) 1999 The Electrochemical Society. S0013- 4651(98)10-071-X. All rights reserved.