Published online by Cambridge University Press: 17 March 2011
Porous methylsilsesquioxane (p-MSQ) films (JSR LKD 5109) were treated withalkyldimethylmonochlorosilanes having chain lengths of one, four, and eightcarbon atoms dissolved in supercritical carbon dioxide at 150-300 atm and50-60°C to repair oxygen ashing damage. Fourier transform infrared (FTIR)spectroscopy showed that trimethylchlorosilane (TMCS),butyldimethylchlorosilane (BDMCS), and octyldimethylchlorosilane (ODMCS)reacted with silanol groups on the surfaces of the pores producing covalentSi-O-Si bonds. Selfcondensation between alkylsilanols produced a residue onthe surface, which was partially removed using a pure scCO2rinse. The hydrophobicity of the blanket p-MSQ surface was recovered aftersilylation treatment as shown by contact angles >85°. The initialdielectric constant of 2.4 ± 0.1 increased to 3.5 ± 0.1 after oxygen plasmaashing and was reduced to 2.6 ± 0.1 by TMCS, 2.8 ± 0.1 by BDMCS, and 3.2 byODMCS.