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

• 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.

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 SiOH 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.