Roles and mechanistic analysis of adenine as a green inhibitor in chemical mechanical polishing

In the process of multilayer copper wiring CMP (chemical mechanical polishing), electrochemical corrosion will occur due to the contact between slurries and metal interface. Inhibitors are added to slurries to reduce the degree of corrosion reactions. In this paper, a new reagent, adenine (AD), was introduced as a corrosion inhibitor. Electrochemical experiments showed that solutions containing AD obtained a higher potential and a more stable OCP curve than solutions without AD. Potentiodynamic polarization tests showed that the corrosion current density decreased with the addition of a 0.1 wt% AD solution. In addition, an increase in AD led to an increase in corrosion potential, and the Tafel slope indicated the anodic corrosion inhibition of AD. AFM (atomic force microscopy) and SEM (scanning electron microscopy) images of the copper surface showed that the addition of AD could improve the surface morphology of copper and reduce the number of corrosion pits. Static etch tests and polishing experiments proved that AD was an effective inhibitor. The inhibitory mechanism of AD was verified through XPS (X-ray photoelectron spectroscopy) and UV-Vis spectrophotometry experiments, which showed that AD under alkaline conditions mainly depended on the adsorption of AD molecules on the surface of Cu to form an adsorption film. In addition, XPS experiments also proved that AD covered the copper surface and was easier to clean than BTA. [GRAPHICS]

Automated summary

The study introduced a new reagent adenine (AD) as a corrosion inhibitor in the chemical mechanical polishing process of copper. The results showed that AD could reduce the corrosion current density, increase the corrosion potential, and decrease the number of corrosion pits on the copper surface.