Improved Chemical-Mechanical Polishing Slurry Composition and Method to Improve Polishing of Metals and Non-metals Using Cerium Oxide Nanoparticles

Reducing manufacturing time, cost, and labor by employing chemistry to transform a two-step process into an easily controlled single-step.
Background: Integrated circuits are built of many layers. Each layer must be perfectly flat so that connections line up between layers and electricity flows properly throughout. Conventional CMP systems consist of three main components: 1. a polishing pad, 2. the polishing slurry, and 3. the surface to be polished (e.g., wafer or optical lens). Manufacturers currently achieve flatness or planarization through a conventional two-step process. The first step coarsely planes the surface using large abrasive particles suspended in a liquid slurry to provide a high removal rate of the desired material, which leaves a rough surface with many grooves or scratches etched by the large particles. The second step polishes the surface using smaller particles and slower rates of abrasion for a fine finish. The slurry must be changed between steps, costing manufacturing time and expense. Technology Overview: This invention describes a one-step process that breaks through this trade-off, offering both fast removal and excellent surface quality simultaneously, reducing manufacturing time, cost and labor. This technology provides an improved chemical-mechanical polishing slurry including ceria nanoparticles and methods of polishing materials using a single CMP slurry.

The technology provides a single-step process that smooths any roughness on the treated surface and does not create scratches in the same way as mechanical polishing. The inventors have modified the CMP slurry and method of polishing by reducing the role of mechanical abrasion and increasing the role of chemical polishing, to improve surface polish without compromising material removal rates. The optimized chemical activity of the slurry is accomplished by processing the ceria nanoparticles before use to enhance their chemical activity and interactivity with and increasing the removal rate of the surface to be polished. The slurry's chemical makeup creates more reactive cerium oxide (i.e., ceria) particles, using significantly less material than comparable silicon oxide particles used in mechanical and conventional CMP polishing.

This invention reduces manufacturing time and costs, minimizes surface scratches to ultimately improve device performance, and generates less environmental pollution and water waste. It can also be tailored to specific products being manufactured, e.g. dielectrics, lenses, and integrated circuits. Advantages:

Applications:

Intellectual Property Summary: Patent application submitted, U.S. patent application number 17/069608 [Publication US 20210108107] Stage of Development: Technology Readiness Level (TRL): 4. Licensing Potential: Development partner, Commercial partner, Licensing Licensing Status: This technology is available for licensing.   https://suny.technologypublisher.com/files/sites/adobestock_64157049.jpeg