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Synthesis and Characterization of Low‐Dielectric Silica Aerogel Films
Author(s) -
Hyun Sang H.,
Kim Joong J.,
Park Hyung H.
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01230.x
Subject(s) - aerogel , materials science , sol gel , dielectric , wafer , spin coating , supercritical drying , thin film , composite material , supercritical fluid , chemical engineering , chemical mechanical planarization , silicon , coating , nanotechnology , layer (electronics) , optoelectronics , organic chemistry , chemistry , engineering
Thin films of silica aerogel on a silicon wafer have been synthesized via supercritical drying of wet gel films that were obtained by spin coating the polymeric silica sol, followed by aging in an isopropanol (IPA) or tetraethoxysilane/isopropanol (TEOS/IPA) solution. The viscosity of the sol and the spin rate required to form uniform coating layers were optimized. The film thickness and microstructures could be controlled by adjusting the concentration of the sol, the spin rate, and the aging conditions. The porosities and the dielectric constants of the thin films were in the range of 76%–90% (densities of 0.59–0.22 g/cm 3 ) and 2.0–1.5, respectively. The degree of planarization in the aerogel thin film was ∼100%, and the gap‐filling capability on a 0.2 μm tungsten patterning wafer was excellent. In particular, aging the wet gel film in the TEOS/IPA solution was very effective in improving the properties of the aerogel films.