| 摘要 |
The charging voltage measuring device includes a measuring electrode for forming an electrostatic capacity Cs with a substrate disposed on a substrate holding unit, a measuring capacitor, which has an electrostatic capacity Cm, being connected between the measuring electrode and a ground potential portion, and, a voltage measuring unit for measuring a measuring voltage Vm across the measuring capacitor, and a calculating unit. The calculating unit 22 calculates the charging voltage Vs on the surface of the substrate at time t 1 in accordance with the following numerical expression on the basis of the measuring voltage Vm(t 1 ) at time t 1 , an inverse K of a voltage dividing ratio and a resistance value Rm of a resistor disposed in parallel to the measuring capacitor 18 , when the measurement time is t 1. <?in-line-formulae description="In-line Formulae" end="lead"?>Vs=K[Vm(t 1 )+{1/(Cm.Rm∫<SUB>0</SUB><SUP>t1</SUP>Vm(t)dt]<?in-line-formulae description="In-line Formulae" end="tail"?> where K=(Cs+Cm)/Cs or K=Cm/Cs (if Cm>>Cs)
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