AVS 51st International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS1-TuM

Paper PS1-TuM1
Polymer Formation in Fluorocarbon Etch Plasmas

Tuesday, November 16, 2004, 8:20 am, Room 213A

Session: Dielectric Etching
Presenter: B. Ji, Air Products and Chemicals, Inc.
Authors: B. Ji, Air Products and Chemicals, Inc.
S. Dheandhanoo, Air Products and Chemicals, Inc.
S.A. Motika, Air Products and Chemicals, Inc.
P.R. Badowski, Air Products and Chemicals, Inc.
J.R. Stets, Air Products and Chemicals, Inc.
E.J. Karwacki, Air Products and Chemicals, Inc.
Correspondent: Click to Email
Recent investigations have shown fluorocarbon (FC) polymers play several key roles in dielectric etch plasmas. A steady state FC film is a key ingredient for etching silicon under ion bombardment. For anisotropic dielectric etching, FC films protect the photoresist mask and passivate the feature sidewalls. In recent years, the semiconductor industry have adopted heavier molecular weight and lower fluorine to carbon ratio gases, such as c-C@sub 4@F@sub 8@, C@sub 5@F@sub 8@, and C@sub 4@F@sub 6@ for anisotropic dielectric etching. In this study, we investigate the correlation between fluorocarbon molecular structure and FC film property. We employ mass spectrometry to determine electron impact fragmentation patterns of various fluorocarbon molecules. We use Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy to characterize the FC polymer structure. We investigate a series of novel dielectric etch gases such as c-C@sub 4@F@sub 8@, C@sub 4@F@sub 8@O, C@sub 3@F@sub 6@, C@sub 3@F@sub 6@O, C@sub 5@F@sub 8@, C@sub 4@F@sub 6@, and C@sub 6@F@sub 6@ etc. The results demonstrate that FC film properties depend not only on the atomic fluorine to carbon ratios, but also on the bonding structures in the molecules. Finally, we correlate the molecular fragmentation patterns and FC film properties to anisotropic dielectric etch performances of various gases.