AVS 53rd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS2-TuA

Paper PS2-TuA3
Plasma Confinement in Multi-frequency Plasma Process Chamber

Tuesday, November 14, 2006, 2:40 pm, Room 2011

Session: Etch for Advanced Interconnect II
Presenter: K. Bera, Applied Materials, Inc.
Authors: K. Bera, Applied Materials, Inc.
D.J. Hoffman, Applied Materials, Inc.
M. Kutney, Applied Materials, Inc.
Correspondent: Click to Email
A production-worthy plasma process chamber needs to confine plasma to minimize chamber contamination, to reduce cleaning time and cost, and to minimize process drift. The process chamber needs to achieve high flow rate at low pressure for critical etch applications. One method to confine plasma can be the use of slotted confinement ring. However, a slotted confinement ring generates significant pressure gradient that prohibits low pressure high flow operation. In addition, ignition of plasma in the peripheral region can lead to process drift that is detrimental to process performance. An annular confinement ring design confines plasma for both VHF and HF operating conditions. The annular ring design is optimized using plasma and flow simulations to ensure plasma confinement and enhance flow conductance. Higher flow conductance leads to lower pressure on the wafer enhancing operating window that allows us to achieve desired process characteristics for critical etch processes. The annular confinement ring avoids parasitic plasma improving productivity. To further enhance plasma confinement, an innovative concept of impedance confinement has been analyzed using plasma simulation. An impedance parameter has been defined, and optimized so as to achieve highly confined plasma. The optimized design of confinement ring with impedance confinement is implemented and verified experimentally for both VHF and HF operating conditions. Annular confinement ring design with impedance confinement not only confines plasma to minimize chamber contamination, reduce cleaning time and cost, but also avoids parasitic plasma to improve productivity, and increases flow conductance to enhance operational window.