Drying and functionalization of triethoxyfluorosilane-based low-k dielectrics in CO2

To minimize the deleterious effects of water on the electrical properties of porous low-k dielectrics in integrated circuits, these materials are chemically treated to create a hydrophobic surface group. Typically, this process is slow and involves a large concentration of organic solvents and silylation agents. We report a method of drying and chemical surface modification of triethoxyfluorosilane-based low-k dielectrics using liquid and supercritical (SC) CO2 as a solvent. CO2 is an environmentally friendly, recyclable solvent, and the use of SC-CO2 allows for full surface modification in less than 5 min with hydrophobic chemical reagent volumes one-thousandth those previously used in bulk chemical modifications. (C) 2003 The Electrochemical Society.