IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Monday Sessions
       Session PS2-MoM

Paper PS2-MoM1
Optical Emission Spectroscopy of Exhaust Stream Gases for Improved Process Control

Monday, October 29, 2001, 9:40 am, Room 104

Session: Diagnostics I
Presenter: G. Powell, Lightwind Inc.
Authors: G. Powell, Lightwind Inc.
C.T. Gabriel, Advanced Micro Devices
Correspondent: Click to Email
Traditional optical emission spectroscopy uses the processing plasma as the light source, limiting the application of OES to when the plasma is on. Another drawback occurs when OES is used in a plasma with a varying magnetic field, which induces signal variations that must be filtered out. We introduce here a new OES technique, where a small secondary plasma is added just downstream of the process chamber to provide a continuous OES light source. The secondary plasma generates emissions characteristic of gases flowing through the chamber or being emitted by the chamber walls, enabling continuous monitoring of species in the chamber. The monitoring can be carried out whether the main chamber plasma is on or off, giving an indication of chamber condition prior to processing a wafer. Signal oscillations from a moving magnetic field are completely removed by monitoring gases downstream of the chamber, simplifying data collection and interpretation for endpointing. Data from using the technique in a MERIE dielectric etch tool are given.