A Study on PMD(Pre-Metal Dielectric) Structure to Prevent Device Degradation Induced by CMP Process

It is very important to select superior Inter-layer PMD(Pre Metal Dielectric) materials which can act as a penetration barrier to various impurities created by CMP processes. In this paper, hot carrier degradation and device characteristics were studied with various PMD-1 layers, such as LP-TEOS SR-Oxide, PE-Oxynitride, PE-Nitride, and PE-TEOS films. The oxynitride and nitride deposited using plasma were greatly degraded the device after hot carrier test compared with silicon oxide. Consequently, silicon oxide turned out to be the better PMD-1 material than PE-oxynitride or PE-nitride. Also, LP-TEOS film was the best PMD-1 material among the silicon oxides.