Using NH3 plasma pretreatment to improve the characteristics of organic spin-on low-k materials for copper metallization

Abstract

Organic low-k materials have got more attention for reducing integrated circuits RC delay time. A serious problem, in degradation of organic low-k materials is induced by ashing step, In this study, an NH3 plasma-treated spin-on low-k material was used as a dielectric layer for Cu metalization. After NH3 plasma treatment for 10 min, the low dielectric constant films can prevent ashing damage without changing their original dielectric constant. An extra advantage of blocking copper diffusion was achieved after NH3 plasma treatment. The improvement of low dielectric constant films was due to an oxynitride film formed on the surface of low dielectric constant film. This oxynitride film also prevents the Cu diffusion/migration into the underlying dielectric and plays a role of passive diffusion barriers.