Effects of double bonding configurations on thermal stability of low-hydrogen concentration fluorinated amorphous carbon thin-films with low dielectric constant prepared by sputtering with hydrogen dilution

摘要

The thermal stability of low hydrogen concentration fluorinated amorphous carbon (a-C : F) thin films with low dielectric constants, prepared by magnetron sputtering with H{sub}2 gas dilution into CF{sub}4 gas was investigated. No changes in the dielectric constant and thickness were observed for the film with a fluorine concentration of 50 at% after annealing at 300℃, indicating that the thermal stability of the film was comparable to that of a film prepared by plasma chemical-vapor deposition. However, an increase in dielectric constant and a decrease in thickness were observed after annealing at 400℃. Infrared absorption spectra of the sputtered films showed the vibration modes due to F{sub}2C=C <, F{sub}2C=CF, HFC=C < and/or H{sub}2C=C < bonding configurations. The effects of these bonding configurations on thermal stability are discussed.