AVS 49th International Symposium
    Plasma Science Monday Sessions
       Session PS-MoM

Paper PS-MoM6
Deposition of Silicon Oxychloride Films on Chamber Walls during Cl@sub 2@/O@sub 2@ Plasma Etching of Si

Monday, November 4, 2002, 10:00 am, Room C-105

Session: Conductor Etch I
Presenter: S.J. Ullal, Lam Research Corporation
Authors: S.J. Ullal, Lam Research Corporation
H. Singh, Lam Research Corporation
V. Vahedi, Lam Research Corporation
E.S. Aydil, University of California, Santa Barbara
Correspondent: Click to Email
Chlorine plasma etching of silicon is widely used in gate etching and shallow trench isolation. During etching, the silicon chloride etch products react with oxygen present in the plasma to deposit a glassy silicon oxychloride film on the chamber walls. The chemical nature and deposition rate of the silicon oxychloride films deposited on the chamber walls during Cl@sub 2@/O@sub 2@ plasma etching of Si were investigated using multiple total internal reflection Fourier transform infrared (MTIR-FTIR) spectroscopy. The differences in the infrared spectra of films deposited under different etching conditions were quantified through the Si-O and OSi-Cl absorption band intensities and positions to determine the growth rate and composition of these films. The changes in the film's deposition rate and composition with rf bias power and O@sub 2@ flow rate gave insight into the deposition mechanism. Based on our experimental observations, we propose that the silicon oxychloride film is deposited through oxidation of SiCl@sub x@ (0@<=@x@<=@4) molecules adsorbed on the reactor walls and suggest a kinetic expression for the film deposition rate. This kinetic expression may also be used judiciously for describing the silicon oxychloride deposition on the sidewalls of etched features in gate etching and shallow trench isolation.