Advanced Polymer Dry Etching Processes for Enhanced Cu/Polymer Hybrid Bonding

Abstract

As semiconductor devices continue to demand higher performance and density, Cu/polymer hybrid structures have gained significant attention due to their potential to replace conventional SiO₂ dielectrics. In this study, we explore the optimization of dry etching processes for 1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane (p $\text {V}_{{3}}\text {D}_{{3}}$ ) a low-dielectric constant polymer ( $k =2.2$ ), used in Cu/polymer hybrid structures. By employing initiated chemical vapor deposition (iCVD) high purity, p $\text {V}_{{3}}\text {D}_{{3}}$ thin films with a thickness of 200 nm were deposited. Various gas mixtures, including O₂, CF₄, and Ar, were used for dry etching to evaluate the optimal etching conditions. Results show that the most anisotropic etching occurred with an O₂/Ar gas mixture, achieving an etching depth of 200 nm and near-vertical sidewalls. Detailed analysis of the etching mechanism was conducted using Gibbs free energy calculations and X-ray photoelectron spectroscopy (XPS). The findings of this study provide valuable insights into the fabrication of high-density, high-performance Cu/polymer hybrid structures for next-generation semiconductor devices.