Catalytic Surface Oxidation of Wide Band Gap (WBG) Substrates for Enhanced Chemical Mechanical Planarization (CMP) Performance

The number of chips on an integrated circuit (IC) must double every two years to fulfill the next generation power and computing capabilities according to Moore’s Law. Wide band gap (WBG) substrates (i.e., silicon carbide and diamond) are emerging as the front runner materials to meet the computing demands of upcoming technologies. These substrates, known for their intrinsic abilities (i.e., high capacitance, thermal stability, and wear resistance), allow for smaller, more powerful devices to be created. For effective production of IC devices, each layer of substrate must be atomically flat. In combination with aggressive chemistries and high sheer force, chemical mechanical planarization (CMP) is used to achieve desired material removal rates (MRR) and a flat surface. Harsh oxidizers (i.e., potassium permanganate) are the current industry standard as they achieve a desirable MRR, but their usage comes at the expense of high surface defects and damage to the environment. Catalyst-activated hydrogen peroxide-based slurries prove to be a promising alternative. The addition of the catalyst allows for the generation of reactive oxygen species (ROS). ROS enhance the oxidizing capacities of the slurry, giving way to comparable MRR while maintaining the integrity of the surface.