AVS 49th International Symposium
    Plasma Science Thursday Sessions
       Session PS-ThA

Paper PS-ThA1
Etching Reaction Mechanism of Organic Low-k Dielectric Employing High-Density Plasmas and Multi-Beams

Thursday, November 7, 2002, 2:00 pm, Room C-103

Session: Dielectric Etch II
Presenter: M. Hori, Nagoya University, Japan
Authors: M. Hori, Nagoya University, Japan
H. Nagai, Nagoya University, Japan
M. Hiramatsu, Meijo University, Japan
T. Goto, Nagoya University, Japan
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An organic film, FLARE, is one of the most prospective candidates for interlayer insulating films with lower dielectric constant (low-k). N@sub 2@/H@sub 2@ and N@sub 2@/NH@sub 3@ gas plasmas have been used for etching organic low-k film without degrading the film quality and etch profile. The organic low-k film etching has been studied in ultrahigh frequency (UHF) plasma and inductively coupled plasma (ICP) employing N@sub 2@/H@sub 2@ and N@sub 2@/NH@sub 3@ gases. The absolute densities of H and N radicals were measured using the vacuum ultraviolet absorption spectroscopy (VUVAS) employing micro-plasma as a light source. N and H radical densities were estimated on the order of 10@super 11@ - 10@super 12@ cm@super -3@ and 10@super 12@ - 10@super 13@ cm@super -3@, respectively. The behavior of etch rate corresponded to that of H radical density. Therefore, H radicals were found to be important species for organic low-k film etching, while N radicals never etched without ion bombardments. To investigate the roles of radicals and ions from view point of fundamental reactions, the organic low-k film etching reaction was investigated using radical and ion beams. H and N radicals (@>=@ 10@super 10@ cm@super -3@) were injected with changing the density under the irradiation of each ion (Ar@super +@, N@sub 2@@super +@, NH@sub 4@@super +@, H@sub 3@@super +@) with an energy of 500 eV. The etch rate of organic low-k film was linearly increased with increasing H radical density, while suppressed drastically by N radical injection. The etched subsurface reactions of radicals were investigated by in-situ X-ray photoelectron spectroscopy (XPS) and fourier transform-infrared attenuated total reflection (FT-IR ATR). The etching reaction mechanism is discussed on the basis of results in plasma and multi-beam etching.