AVS 45th International Symposium
    Plasma Science and Technology Division Tuesday Sessions
       Session PS2-TuM

Paper PS2-TuM1
Very Uniform and High Aspect Ratio Anisotropy SiO@sub2@ Etching Process in Magnetic Neutral Loop Discharge Plasma

Tuesday, November 3, 1998, 8:20 am, Room 318/319/320

Session: Oxide Etching
Presenter: W. Chen, ULVAC Japan Ltd.
Authors: W. Chen, ULVAC Japan Ltd.
T. Hayashi, ULVAC Japan Ltd.
M. Itoh, ULVAC Japan Ltd.
Y. Morikawa, ULVAC Japan Ltd.
K. Sugita, Tokai University, Japan
H. Shindo, Tokai University, Japan
T. Uchida, ULVAC Japan Ltd.
Correspondent: Click to Email
Magnetic Neutral Loop Discharge (NLD) plasma@footnote 1@ is a new plasma source for dry etching process, and characterized by a well coupling of the input electric field to the electron motion near the Magnetic Neutral Loop (NL) region. Therefore a dense plasma can be produced and controlled spatially by changing the position of the NL.@footnote 2@] As an evidence, uniform SiO@sub 2@ etching was successfully carried out in several kind of gases and/or those mixture by setting the suitable NL positions.@footnote 3@ Three topics are reported here, which are very uniform etching process by temporal and spatial NL control, high aspect ratio etching for nano-scale pattern in a CHF@sub 2@@super +@ rich plasma and effect of a simple parallel antenna structure for NLD plasma production. In the uniformity control, the deviation of SiO@sub 2@ etch rate was obtained within 3.0% (3 @sigma@) on 200mm diameter wafer, by changing the radius of NL temporally during the etching where the magnetic coil current was varied sinusoidally from a constant value with the repetition frequency of 0.1Hz. Meanwhile the etched profiles of the 0.4 micrometer hole pattern with about 2 micrometer in depth were almost vertical (about 89-90 degrees) at the wafer center and edge. In nano-scale pattern etching process, we found that CHF2+ ions played an important role in a very high aspect ratio profile etching. In a CHF@sub 2@@super +@ ion rich plasma ZEP photo-resist patterned 20nm space was successfully etched with 800nm in depth at the pressure of about 0.3Pa, where CH@sub 2@F@sub 2@, C@sub 4@F@sub 8@, O@sub 2@ gases were used. For plasma production, we proposed a parallel turn antenna, which is characterized in low inductance and larger volume plasma heating in comparison with a conventional single turn antenna. Therefore a high density, low electron temperature plasma with a large diameter of about 0.5m can be produced by 13.56MHz as well as 27MHz power supplies. @FootnoteText@ @Footnote 1@T. Uchida, Jpn. J. Appl. Phys., 33 (1994) L43 @Footnote 2@T. Uchida, AVS 44th National Meeting (1997) ID#98, Conf. Paper #PS1-TuM1 @Footnote 3@W. Chen, M. Itoh, T. Hayashi and T. Uchida, ibid ID#207, Conf. Paper #PS2-WeM1