Planar wafer transport and positioning on an air film using a viscous traction principle

In this paper a new contactless transport system for thin, flat products, such as silicon wafers, is introduced. The product is carried on a thin aerostatic film between the product and the transport system and transported along the system using viscous traction on the product surface. This viscous traction is the result of pressure driven air flow in an array of actuator cells. Several possible industrial applications are discussed, followed by an explanation of the operating principles. Furthermore an analytical model of the system is presented, together with computational results. Numerical modeling using FEA, solving for the incompressible Navier–Stokes equations, shows results that are in good agreement with the described analytical model and some experimental results. The maximum acceleration and vertical bearing stiffness that can be obtained for the considered actuator geometry meet the requirements for the considered industrial applications.