Investigating the Role of Fluid Dynamics on Cut Width Accuracy in Wet Bevel Cleaning Techniques

In this paper, we investigate the role of fluid dynamics on cut width accuracy in wet bevel cleaning techniques. As integrated circuit (IC) manufacturers scale down technology nodes, defects from the wafer edge result in significant yield loss. The two main wet bevel cleaning techniques, backside center dispense spin (BCS) and bevel nozzle dispense spin (BVS), have not been thoroughly compared. Computational fluid dynamics (CFD) models were developed to study the liquid flow. BCS generates non-axisymmetric backside flow, leading to non-uniform cut width profiles. BVS produces a stable circular flow, resulting in a more uniform cut width profile. The cut width profile after BCS is influenced by wafer surface properties, hindering etching of hydrophobic bevel films. BVS is less affected by surface properties, making it easier to achieve the target cut width. The CFD model can be utilized as a digital twin to optimize BVS conditions based on film material properties. This study advances the understanding of fluid dynamics in wet bevel cleaning for improved wafer yield near the edge.