Effect of plasma treatments on ultra low-k material properties

The physical properties and stability of surface modified PECVD SiOC(H) ultra low k (ULK) films were studied. Various stacks exposed to different plasma treatments, such as H2-, NH3-, He- and O2-based chemistry, were evaluated. Ellipsometric measurements, TOF-SIMS analysis, FTIR spectroscopy, adhesion tests and dielectric constant measurement were performed to evaluate the impact of each process on the ULK properties and to determine the best plasma treatments to apply. Mechanisms are proposed to explain the mode of both adhesion and compositional modification. Treatments were identified which enhance adhesion without degrading the dielectric constant integrity, thereby enabling the ULK integration for C065 technologies and beyond.