LAUSR

Abstract The cleaning of copper surface after chemical mechanical polishing (CMP) process is the necessary step since the surface could become contaminated by a large amount of defects. In this study, the adhesion forces between silica particles and copper surfaces have been investigated in citric acid based cleaning solution during post-Cu CMP cleaning process. Potassium hydroxide (KOH) and tetra methyl ammonium hydroxide (TMAH) were used to adjust the pH and Triton X-100 was used as a surfactant. The adhesion forces as well as the zeta potentials decreased with the addition of pH adjustors and surfactant as the concentration of citric acid was 0.5 wt%. By measuring the zeta potentials of silica particles and copper surfaces, the interaction forces between them were calculated based on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory which verified the experimental results. It was also demonstrated that silica particles could be removed efficiently by the proposed solution under cleaning process experiments.