| Summary: | 碩士 === 國立交通大學 === 電子工程學系 === 85 === Interconnect delay is a performance-liming factor for ULSI
circuits when feature size is scaled into the deep submicron
region. Using low dielectric constant material for the
interlayer insulator is an effective way to solve the
problem. We study three kinds of low dielectric
constant material, including fluorine doped oxide(
SiOF), methylsilsesquioxane spin on polymer and hydrogen
silsesquioxane spin on glass. PECVD fluorine doped oxide(
SiOF) is a popular way to reduce the dielectric constant,
but it is reported that SiOF film with high level of fluorine
incorporation have been shown to be unstable because of moisture
absorption. In this work, NH3 plasma post-treatment are applied
to as-deposited SiOF films. Moisture resistance and dielectric
constant stability are investigated. We found that NH3 plasma
post-treatment is quite efficient to enhance the capability of
moisture absorption resistance of SiOF. In addition, two novel
SOG material with permittivity lower than silicon dioxide
interlevel dielectric have been developed. Those SOG can offer
a k of less than 3.0. Two kinds of low k SOG are investigated,
one is organic material-methylsilsesquioxane, the other is
inorganic-hydrogen silsesquioxane. These spin on glass can offer
low dielectric constant (~2.7) on the optimal conditions. The
intrinsic properties and thermal stability of these spin on
glass are investigated. We found that the thermal stability
of methylsilsesquioxane is good because of Si-C
bone in the film, and the thermal processing of hydrogen
silsesquioxaone must be done carefully to attain the
lowest dielectric constant.
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