Multi-scale simulation and flow field characteristics of polishing pad groove structures

The polishing pad is a key consumable in chemical–mechanical planarization (CMP), and its groove structure significantly regulates the slurry transport capacity and debris removal efficiency. This study establishes a Computational Fluid Dynamics model to systematically analyze, for the first time, the flow field characteristics of radial groove (RG), concentric groove, and eccentric groove (EG) polishing pads (with different eccentricity distances). The effects of groove structure on process performance are further investigated experimentally. Furthermore, based on mixed lubrication theory, the mechanisms by which groove width, depth, and spacing affect flow field characteristic parameters are revealed, thereby clarifying the dimensional optimization directions for different groove structures. The results indicate that the EG pad exhibits the highest slurry saturation degree; the periodic fluctuation in its flow field helps optimize the slurry distribution state, thereby improving global planarity. Appropriately increasing the groove width can improve the problem of low slurry saturation degree. The RG pad exhibits a higher slurry mass flow rate, which enhances the chemical corrosion effect and improve debris removal efficiency. Appropriately increasing the groove spacing can ameliorate the problem of low slurry saturation degree. By constructing a multi-scale correlation model, this study reveals the intrinsic relationship between polishing pad structure and its flow field characteristics, along with the parameter regulation rules, providing theoretical support for optimizing polishing pad structure design and enhancing CMP process controllability.