Three-Dimensional Numerical Simulation on the Effects of a Rotating Brush on Liquid Film Flow and Chemical Distribution over a Rotating Disk Using OpenFOAM

抄録

This study numerically computes the interaction between the flow of the cleaning solution and a roller brush on a rotating disk and investigates the effects of brush rotation on the agitation and concentration distribution of the solution for post-chemical mechanical planarization cleaning. The solution flow is handled by applying a previously developed method for solving concentration distribution to a solver for gas–liquid two-phase flows provided by OpenFOAM. The brush is treated as a rigid body; the interference caused by its rotation is simulated using either an overset or a sliding mesh, depending on the conditions. When the nodules of the roller brush interfere with the flowing liquid film, those moving against the flow agitate the solution in the vertical direction of the disk, whereas those moving in the same direction as the flow agitate the solution in the horizontal direction of the disk. At a low flow rate, the entire disk exhibits difficulty getting wet. Initially covering the disk with a liquid film helps mitigate this issue; however, achieving a uniform distribution of the liquid film is still difficult. The effects of the roller brush on the liquid-film formation and solution distribution on the rotating disk confirm that brush rotation promotes the wetting spread of the liquid film and reach of the solution to the disk top surface. Enhancing the delivery and homogenizing the distribution of chemical solutions are expected to contribute to uniform and efficient cleaning processes that utilize chemical reactions, especially when the chemical-reaction timescale is shorter than that of fluid transport.