AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoA

Paper PS-MoA9
Plasma and Surface Diagnostics in Cl@sub 2@/O@sub 2@ Discharges in Transformer Coupled Plasma Reactors

Monday, October 25, 1999, 4:40 pm, Room 609

Session: Plasma Diagnostics I
Presenter: E. Edelberg, Lam Research Corporation
Authors: E. Edelberg, Lam Research Corporation
S. Ullal, University of California, Santa Barbara
A. Godfrey, University of California, Santa Barbara
V. Vahedi, Lam Research Corporation
J.E. Daugherty, Lam Research Corporation
N. Benjamin, Lam Research Corporation
A. Perry, Lam Research Corporation
D. Cooperberg, Lam Research Corporation
R. Gottscho, Lam Research Corporation
E.S. Aydil, University of California, Santa Barbara
Correspondent: Click to Email
Plasma etching with high density transformer coupled plasma (TCP) reactors has become a ubiquitous process in microelectronics because of its ability to transfer patterns from a mask onto an underlying film with precision unequaled by any of the other etching methods. TCP reactors are operated at low pressures where the mean free paths of species are comparable to reactor dimensions. Thus, the role of walls and surface reactions has increased over the role of gas phase reactions in determining the plasma properties and etching behavior. This is most apparent when a stack of thin films of different materials must be etched sequentially in the same reactor using different gases. Chemicals used for etching one material adsorb onto the walls and contaminate the plasma in the following steps and may have deleterious effects on etching of other materials in the stack. In this study, we have explored the effects of wall adsorbates on the plasma properties. The objective is to understand how chemicals adsorbed on walls during one etching step affect the plasma properties in the following steps. Silicon trench isolation using Cl@sub 2@/O@sub 2@ plasmas is taken as a model process and plasma properties and their dependence on the wall conditions were studied through multiple plasma and surface diagnostics including, downstream Fourier transform infrared spectroscopy, in situ multiple total internal reflection Fourier transform infrared spectroscopy, optical emission actinometry, and Langmuir probe.