SBIR Phase I: Chemically Impregnated Nanoparticles for Use in Copper Chemical Mechanical Planarization Slurry

This Small Business Innovation Research Phase I project is focused on the development of a copper chemical mechanical planarization (CMP) slurry containing chemically impregnated nanoparticles. The CMP process consists of a polishing pad and an aqueous slurry containing chemicals and abrasive nanoparticles. The wafer surface to be planarized is rotated against the polishing pad which is continuously supplied with slurry. The synergistic combination of mechanical abrasion and chemical etching creates high material removal rates (MRR) and rapid planarization. Currently, copper CMP slurry solutions require a complexing agent, such as glycine, to maintain an adequate MRR, which at the same time, also causes static etching and dissolution (i.e. corrosion) of the wafer surface which is difficult to control. If the exposure of the complexing agent to the copper surface could be controlled so that only the abraded areas were affected, then static etching and dissolution could be reduced or eliminated. Therefore, the focus of this proposal is to significantly improve copper CMP slurry technology by combining the complexing agent into the abrasive nanoparticle, so that mechanical and chemical actions of the slurry are localized and simultaneous, thus improving processing efficiency and tolerances. The broader impact/commercial potential of this project includes advancing the state-of-the-art in CMP slurry formulation and opening the door for functionalized nanoparticles in the CMP slurry market. Specific impacts of the proposed project on copper CMP slurry technology include: increasing planarization efficiency (ratio of step height reduction and removed layer thickness) by decreasing static etching, eliminating a majority of the chemical additives that are currently required in copper CMP slurries, and reducing particle agglomeration by improving the dispersion stability. These advantages will ultimately lead to a reduction in the cost of CMP processing while also improving processing tolerances. Additionally, an enormous opportunity exists to exploit functionalized nanoparticles to improve CMP slurries. Successful implementation of this product will most certainly lead to derivative technologies for other CMP processes.