Sol-gel derived mesoporous silica films used as low dielectric constant materials

This paper presents the results of fabrication and characterization of mesoporous silica films used as intermetal dielectrics (IMD). The films were fabricated via sol-gel process using tetraethyl orthosilicate (TEOS) and methyltriethoxysilane (MTES) as precursors with acid and base as catalysts. Various surface modifications were conducted to remove the surface silanol groups and maintain the dielectric constant of the films low. The film characterization results show that the microstructure of the films such as pore size and porosity can be tailored by controlling the molar ratio of TEOS and MTES. An ultralow dielectric constant of around 2.0 was realized for about 56% porosity in the silica film with pore sizes less than 10 nm. Preliminary results of the silica films prepared here present a very positive prospective to IMD applications.