Low dielectric constant Parylene-F-like films for intermetal dielectric applications

We report on the dielectric properties and thermal stability of thin polyme r films that art: suitable candidates for replacing silicon dioxide as the intermetal dielectric material in integrated circuits. Parylene-F-Iike film s, (-CF2-C6H4-CF2-)(n), were produced by plasma deposition from a mixture o f Ar and 1,4-bis(trifluoromethyl)benzene (CF3-C6H4-CF3) discharges and char acterized using infrared absorption spectroscopy, spectroscopic ellipsometr y, and capacitance measurements. The dielectric constant and the magnitude of the electronic and ionic contributions to the dielectric constant were d etermined through capacitance measurements and Kramers-Kronig analysis of t he infrared absorption data. The film's dielectric constant ranges between 2 and 2.6 depending on the deposition conditions and the largest contributi on to the dielectric constant is electronic. The films deposited at 300 deg rees C are stable above 400 degrees C and further optimization could push t his limit to as high as 500 degrees C. (C) 1999 American Institute of Physi cs. [S0003-6951(99)04304-1].