Real Time Analysis of Remote Oxygen and Hydrogen Plasma Cleaning using Mass Spectroscopy

Abstract

The plasma cleaning technologies have been attracting a great attention due to the demands of the compatible process with the most cluster tool and of the enviromentally safe process. The photo resist (PR) ashing and PR strip process are generally followed the silicon etching process to remove the PR and polymerized residues, respectively, during integrated circuit fabrication. However, the PR strip is the wet chemical process and causes environmental problems. Especially, the polymerized residues formed at the contact and via holes during the photo resist (PR) ashing and PR strip processes must be removed prior to the metal contact. In this study, we continuosly monitored and systematically analyzed the volatile gases from the oxidized PR molecules during the low temperature remote plasma cleaning process. Mass spectroscopy (QMS200) was used for the real time monitoring of the volatile gases containg carbon and fluorine. In-situ Auger electron microscopy, X-ray photoelectron spectroscopy, atomic force microscope analysis systems were used to evaluate the cleaning effects and to avoid recontamination such as carbon absoption in the air. The surface morphologies of the samples before and after plasma cleaning were also observed using scanning electron microscope. This paper will present the oxygen and hydrogen remote plasma cleaning efficiency and its chemical reaction mechanisms.