| 摘要 |
PURPOSE:To prevent the generation of treatment nonuniformity and defects, and improve yield and productivity, by installing a ring-type means to uniformly restrain an ascending air flow generated by the rotation of an object to be treated. CONSTITUTION:Between the periphery of a straightening plate 7 and a cup 5, a ring-type means to restrain uniformly an ascending air flow generated by the rotation of a wafer 1 is installed. A ring-type porous member 8 whose upper surface is horizontal, for example, is used as the above mentioned means. As the result of rotation of wafer 1, rotating air flow of about several m/sec proportional to the number of revolution is generated. In the case where the shape of the cup 5 is nonsymmetric with respect to the rotation center, that is, an annular bottom of the cup 5 is inclined, a part of the rotating air flow is turned into an ascending component as the result of volume changing. Thereby, the following phenomena can be prevented; fine mist of resist wast liquor scattered from the wafer 1 surface is again carried to the wafer 1 and attached to the surface, and treatment nonuniformity and defects of the wafer 1 are generated. |
