Deposition of silicon dioxide films on fluorinated amorphous carbon films (a-C:F) for low dielectric constant interlayer dielectrics was investigated. Both SiO2 and a-C:F films were deposited by helicon wave plasma enhanced chemical vapor deposition with C4F8 for a-C:F and SiH4+O2 mixtures for SiO2. The SiO2 films on the a-C:F films peeled off soon after deposition. However, the peeling was suppressed by inserting a thin a-C:H buffer layer grown from CH4 between them. The adhesion between the films was increased by making the stoichiometry of SiO2 Si-rich. It was found that the Si-C bonds formed at the interface increased the adhesion.