AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS+MS-TuM

Paper PS+MS-TuM3
Coupled Diagnostic Studies of Plasma Etch Byproducts

Tuesday, November 5, 2002, 9:00 am, Room C-105

Session: Plasma Diagnostics and Sensors
Presenter: M.T. Radtke, University of California Berkeley
Authors: M.T. Radtke, University of California Berkeley
D.B. Graves, University of California Berkeley
J.W. Coburn, University of California Berkeley
Correspondent: Click to Email
Plasmas used for etching invariably include species that originate at surfaces. Etch byproducts commonly play a major role in plasma composition, in addition to influencing etch rate, anisotropy, critical dimension control, and selectivity. Etch byproducts often deposit on chamber walls, altering wall chemistry such as radical recombination reactions, and leading to the formation of particles. Chamber wall cleaning and conditioning protocols can play an important role in etch tool cost-of-ownership. For new high-k and low-k dielectrics and metal gate electrode materials, the etch characteristics and etch byproducts are usually not known. In addition to posing a challenge for feature critical dimension control and other etch objectives, the unknown etch byproducts may pose environmental, health and safety hazards. We reports studies using an inductively coupled plasma reactor equipped with a cooled, rf-biased chuck, a downstream FTIR spectrometer, a quartz crystal microbalance, a Langmuir probe, an ion flux wall probe, an ion mass spectrometer, a separate threshold ionization mass spectrometer for neutral radical detection, and optical emission spectroscopy. We have employed this system to measure etch byproducts and etch byproduct transport for a range of new high-k and low-k dielectric materials as well as candidates for metal gate electrodes. We illustrate the use of coupled plasma diagnostics for ZrO@sub 2@/Cl@sub 2@, SiO@sub 2@/CF@sub 4@, RuO@sub 2@/O@sub 2@, HfO@sub 2@/Cl@sub 2@, and Si/Cl@sub 2@/O@sub 2@. In particular, detection and identification of low volatility byproducts can be challenging, and often require combining information from the ion mass spectrometer, the neutral mass spectrometer, film composition measurements on the quartz microbalance, optical emission spectroscopy, and the downstream gas composition.