The reaction of octyldimethylchlorosilane (ODMCS) dissolved in supercritical carbon dioxide (scCO 2) at 160-200 atm and 54-60°C with oxygen plasma ashed porous methylsilsesquioxane (p-MSQ) films (JSR LKD 5109) was studied using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, and electrical measurements. The FTIR results showed that ODMCS reacted with silanol groups on the surface of the pores producing covalent Si-O-Si bonds. Self-condensation between ODMCS produced a physisorbed residue, which was partially removed by rinsing with pure scCO 2. XPS results showed no Cl was left on the surface after processing. The hydrophobicity of the oxygen plasma treated p-MSQ surface was recovered, and the dielectric constant of 2.4 for nonashed, blanket p-MSQ surface was restored. With increasing concentration of ODMCS from 32 to 156 ppm, the contact angle increased from 77° to 94°, yet the dielectric constant measured on metal-insulator-semiconductor capacitors was approximately constant in the range 2.3-2.4. ODMCS dissolved in scCO 2 restored the dielectric constant and surface properties of mesoporous p-MSQ and is a candidate for pore sealing.
ASJC Scopus subject areas
- Chemical Engineering(all)