Deposition of silicon dioxide films on amorphous carbon films by plasma enhanced chemical vapor deposition for low dielectric constant interlayer dielectrics

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.