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

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 (pV<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>D<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>) a low-dielectric constant polymer (k=2.2), used in Cu/polymer hybrid structures. By employing initiated Chemical Vapor Deposition (iCVD) high purity, pV<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>D<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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.