Investigating the tribochemical corrosion effects during simulated p-CMP cleaning with various metal substrates

Chemical Mechanical Planarization (CMP) is a crucial step in producing defect-free planar surfaces utilizing a combination of abrasive slurries, cleaning chemistry, PVA brushes, and polyurethane pads. Despite various refinement methods, defects such as etching, scratching, and corrosion are still an integral concern in current post CMP processes. To understand this phenomenon better, an investigation into the tribochemical corrosion effects of various metal substrates (e.g., Cu, Mo, etc.) in a simulated cleaning environment was conducted to explore the dynamics at the 3-body interface (brush, substrate, chemistry). The macroenvironment was studied by varying experimental conditions, including dissolved oxygen level, mechanical force, and cleaning chemistry to determine the process conditions that induce corrosion or modulate passivation at the three-body interface. Preliminary data indicates a decrease in the oxidation rate of the substrate with reduced oxygen saturation in the cleaning solution.