Stress control of Si-based PECVD dielectrics

Abstract

The Si-based dielectric films, silicon dioxide (SiO 2) and silicon nitride (SiN x) prepared by plasma-enhanced chemical vapor deposition (PECVD), are used in device fabrication throughout the microelectronics and optoelectronics industries, The stress of these films can affect the electrical and optical characteristics as well as the integrity and reliability of the devices, In this paper, results are presented on a study of different techniques for stress control of these films. This includes discussion of a simple stress control method and the mechanism involved for SiN x achieved by addition of He to the standard SiH 4, NH 3, and N 2 plasma chemistry. A designed experiment has been used to optimize a low stress SiN x process based on this method on a commercial PECVD reactor developed for volume GaAs manufacturing.