Jpn. J. Appl. Phys. 44 (2005) pp. 2971-2975 |Previous Article| |Next Article| |Table of Contents|
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Effect of CHF3 Addition on Reactive Ion Etching of Aluminum Using Inductively Coupled Plasma
1Graduate School of Science and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 273-0035, Japan
2Corporate Manufacturing Engineering Center, Toshiba Corporation, 33 Shin-isogo-cho, Isogo-Ward, Yokohama 235-0017, Japan
(Received April 20, 2004; accepted February 10, 2005; published May 10, 2005)
The role of CHF3 gas addition in reactive ion etching (RIE) processes using inductively coupled plasma for aluminum wirings were investigated. With increasing of the amount of CHF3 gas addition to the etching gas, the pattern profile changed from reverse to ordinary taper and the pattern width increased. It was considered that by adding CHF3 to the main etching gas, a larger amount of passivation layer deposited on the sidewall of the resist and Al pattern, which suppressed side etching of the pattern. To clarify the role of CHF3 addition, XPS, FT-IR and TDS analyses were carried out to study the structure of the passivation layer. Consequently, it is considered that the pattern sidewall is composed of AlF3, an organic polymerized film and a passivation layer including ammonium salt and B oxide. Due to the addition of CHF3 gas into the etching gas, AlF3 is additionally formed, which is deposited on the pattern sidewall, resulting in the change of the etched pattern profile and width.
KEYWORDS:plasma, etching, aluminum, anisotropic, pattern profile
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