| 摘要 |
<p>PURPOSE:To provide a substrate retainer, in which attraction applied from electrostatic chuck to substrate can be kept constant even if the surface condition of the substrate and an ambient atmosphere change. CONSTITUTION:A sensor 22 for measuring attraction applied from electrostatic chuck 2 to substrate 10 and for outputting a measurement signal S2 corresponding to the attraction is attached to the rear side of the electrostatic chuck 2. Also, the difference between the measurement signal S2 and set value K2 is obtained and an attraction control circuit 26 for controlling voltages +V, -V outputted from an attraction power supply 12a is provided so that the difference approaches 0.</p> |
