Effect of O₂ plasma treatment on physical, electrical, and reliability characteristics of low dielectric constant materials

The degradation induced by oxygen (O₂) plasma irradiation to the various low dielectric constant materials (low-k; k = 3.0–2.5) has been investigated in this study. The dielectric constant was observed to increase upon O₂ plasma treatment due to carbon atom depletion and Si-OH bond formation, which is strongly influenced by the bonding structure or strength of the low-k materials, and less related to the porosity. Moreover, the O₂ damage can be suppressed by densifying the low-k film's surface induced by He/H₂ remote plasma treatment. Additionally, the role of ions, photons, and radicals in the plasma in inducing the low-k material degradation was clarified by using a special designed structure. The experimental results showed that all components in the plasma have contributions in degrading the electrical and reliability performance of low-k film. Moreover, the synergy between the radicals, the photons, and the ions enhanced the damage. - Highlights: • Effect of O₂ plasma irradiation on the various low-k films • Role of ions, radicals, and photons in inducing plasma damage to porous low-k films • O₂ plasma damage on low-k films can be suppressed by performing He/H₂ remote plasma treatment. • Synergy between the radicals, the photons, and the ions enhanced the damage