Advance on molecular dynamics simulations of precision polishing of SiC

【Background】SiC has high hardness, brittleness, and chemical stability, making it exceptionally difficult to perform ultra-precision processing on its surface. This results in high processing costs, severely limiting the application and development of SiC in high-end devices. Chemical mechanical polishing (CMP) is a key technology for the planarization of SiC substrates. Currently, there is a large amount of research on CMP polishing processes, but the interaction mechanism between abrasives and chemicals in the solvent and the SiC surface is not clear. Molecular dynamics (MD) simulation, based on Newton's motion law and quantum mechanics principles, is a simulation method used to reveal the interaction between microstructure and properties of substances. It is widely used in the study of the removal mechanism of SiC surfaces.
【Content】The article first summarizes the current mainstream chemical mechanical polishing methods and their enhancement methods. Then, it analyzes the commonly used potential functions in MD simulations of SiC precision polishing, and summarizes their application areas in SiC chemical mechanical polishing based on the characteristics of potential functions. Finally, the existing research on MD simulation of SiC chemical mechanical polishing is integrated and analyzed, summarizing the removal behavior of abrasives on the SiC surface and the mechanism of adsorption and oxidation of solutes and solvents in the polishing liquid on the SiC surface, and prospects for future research directions in SiC chemical mechanical polishing.
【Current Status】The results indicate that mature simulation methods have been developed for mechanical behaviors in SiC CMP MD simulations, particularly in simulating abrasive-SiC surface interaction mechanisms and mechanical properties. The Tersoff potential, as the most classical description of the interaction between silicon and carbon atoms, can well describe the mechanical behavior of SiC and is used to study the mechanical properties and structural changes of SiC. The ABOP potential function is suitable for describing the atomic interactions of SiC materials.The Vashishta potential function is mainly used to simulate the deformation of 3C-SiC ionic bonds and covalent bonds. ReaxFF reactive force field, because it can support the formation and fracture of chemical bonds, is often used to study the chemical reactions and adsorption behavior of SiC surfaces. MD simulation of SiC substrate precision polishing is mainly divided into three categories: SiC material properties, abrasive grinding, and SiC surface chemical reactions. At present, most research focuses on the mechanical behavior between abrasives and SiC surfaces, with relatively few studies on chemical reaction mechanisms.
【Prospects】Currently, there are still many unclear issues in the CMP mechanism of SiC materials. Molecular dynamics simulations can be used to study the interaction mechanisms between liquids, oxides, and surfaces in chemical mechanical polishing, such as charge transfer and surface adsorption. In the future, the focus of research will be on using ReaxFF reactive force fields to study the reaction mechanisms of SiC under various conditions through molecular dynamics simulations, building more potential functions to adapt to different polishing conditions, and establishing comprehensive models considering the effects of multiple factors on surface interactions.