| 摘要 |
<p>PROBLEM TO BE SOLVED: To measure a precise wafer potential in real time and without being subjected to the influence of peripheral structures and to quickly detect a charging-up phenomenon in an ion implantation apparatus by which a wafer is irradiated with an ion beam. SOLUTION: In an electrostatic chuck device 41, electrodes 43, 44 are buried inside a mounting base 42 composed of a dielectric material, attraction currents are supplied to the electrodes 43, 44 from power supplies 46, 47 for attraction, and a wafer 29 is attracted. In the electrostatic chuck device, a wafer 29a for a sample is placed in advance, a variable voltage Vps is applied from a DC power supply 58, and values of attraction currents Iesc+, Iesc- by ampere meters 51, 52 with reference to a wafer potential Vwafer at this time are found. When the wafer 29 is irradiated actually with an ion beam 59, the wafer potential is found on the basis of the measured attraction currents.</p> |
