Measuring instrument and measuring method

A method of measuring an electrostatic capacitance by using a measuring instrument in a chamber of a processing system,

• wherein the processing system includes:
• a process module having a chamber body for providing the chamber;
• a transfer unit configured to transfer the measuring instrument into the chamber;
• an electrostatic chuck provided in the chamber and on which the measuring instrument is mounted;
• and
• an edge ring disposed so as to surround a peripheral edge of the electrostatic chuck;
• wherein the measuring instrument includes:
• a disc-shaped base board;
• at least one sensor chip on the base board;
• and a circuit board on the base board,
• wherein the at least one sensor chip includes a sensor unit including a signal electrode having a front surface intersecting the base board in a radial direction, a guard electrode disposed on a rear side of the signal electrode while being spaced apart from the signal electrode and extending along the signal electrode, and a first ground electrode disposed on a rear side of the guard electrode,
• the circuit board includes
• a radio frequency oscillator configured to apply a radio frequency signal to each of the signal electrode and the guard electrode, and
• a C/V conversion circuit configured to generate a voltage signal according to an electrostatic capacitance formed by the signal electrode,
• the C/V conversion circuit has an amplifier circuit including an operational amplifier,
• the radio frequency oscillator is connected to a non-inversion input terminal of the operational amplifier so that the radio frequency signal applied to the guard electrode is input to the non-inversion input terminal, and is connected to an inversion input terminal of the operational amplifier so that the radio frequency signal applied to the signal electrode is input to the inversion input terminal,
• the at least one sensor chip includes a second ground electrode extending along a lower surface of the sensor unit,
• the signal electrode, the guard electrode, and the first ground electrode of the sensor unit all extend to a lower end of the sensor unit, and
• a space between the second ground electrode and the sensor unit is filled with a material having insulating properties
• wherein the method comprises:
• transferring the measuring instrument onto the electrostatic chuck using the transfer unit;
• and
• generating at least one measurement value representing electrostatic capacitance by applying a radio frequency signal to the electrode in a state where the measuring instrument is placed on the electrostatic chuck;
• wherein, in the generating the at least one measurement value, the signal electrode is shielded from a rear by the guard electrode and the first ground electrode, and is shielded from a lower part by the ground electrode.