| 摘要 |
PURPOSE:To contact a wafer and a mask quickly, stably and closely without holding and confining a gas between the wafer and the mask, by aligning many small holes, which are arranged on a wafer mounting surface of an X-Y table, along radial lines, which are set on the wafer mounting surface. CONSTITUTION:Grooves 9f, 9g and 9e are arranged along respective radial lines R1-R8. Small holes 2f, 2g and 2e are provided at the end parts close to the centers of the respective grooves 9f, 9g and 9e. By using a sucking pad constituted in this way, a wafer 3 is sucked and held. Then, the wafer 3 is pushed up with N2 gas. The gas jetting parts are quickly expanded from the central small hole 2d to the peripheral small holes 9e in sequence. Since the many small holes 2f, 2g and 2e are provided along the respective radial lines R1-R8, stable, close contact effect can be obtained without holding the N2 gas. Since the radial grooves are provided, the pressure of the N2 gas is symmetrically distributed in a polar coordinate with respect to the central point as shown by a constant-pressure line P1 indicated by an imaginary line, the gas is not held when the close contact is made to progress from the central part to the peripheral part in sequence. |
