Ultralow dielectric constant pSiCOH films prepared with tetramethylcyclotetrasiloxane as skeleton precursor

Abstract

Ultralow dielectric constant pSiCOH films have been prepared using tetramethylcyclotetrasiloxane (TMCTS) as the skeleton precursor and two different porogen precursors. The porogen has been removed from the deposited films by thermal annealing at 400°C, obtaining films with dielectric constants down to 1.95. The films have been investigated by Fourier transform infrared spectroscopy, and n&k optical measurements of the refractive index (n) and the electrical characteristics have been measured on metal-insulator-semiconductor structures. It was found that the properties of the annealed films depend on the deposition temperature and used porogen, different concentrations of porogens in the plasma feed being required to obtain the same final dielectric constant. The efficiency of porogen incorporation in the films prepared from TMCTS was very low and was dependent on the selected porogen precursor. © 2008 American Institute of Physics.