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.