Measuring instrument and measuring method

Patent metadata

Field	Value
Publication number	US-12222379-B2
Application number	US-202218145663-A
Country	US
Kind code	B2
Filing date	Dec 22, 2022
Priority date	Dec 27, 2021
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A measuring instrument according to an exemplary embodiment includes a base board, at least one sensor chip provided on the base board, and a circuit board provided on the base board. 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, and a first ground electrode disposed on a rear side of the guard electrode. The at least one sensor chip includes a second ground electrode extending along a lower surface of the sensor unit. A space between the second ground electrode and the sensor unit is filled with an insulating material.

First claim

What is claimed is:

1. A measuring instrument comprising: 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.

2. The measuring instrument according to claim 1 ,
wherein the space between the second ground electrode and the sensor unit is filled only with the material having insulating properties.

3. The measuring instrument according to claim 1 ,
wherein the guard electrode constituting the sensor unit does not include a portion extending along the lower surface of the sensor unit.

4. The measuring instrument according to claim 1 ,
wherein in a plan view, the front surface of the signal electrode, a front surface of the guard electrode, and a front surface of the first ground electrode are curved surfaces in parallel to a curved surface along an outer periphery of the base board.

5. The measuring instrument according to claim 1 ,
wherein the at least one sensor chip includes a first flexible board having insulating properties, extending along the lower surface of the sensor unit, and including the second ground electrode.

6. The measuring instrument according to claim 1 ,
wherein the at least one sensor chip includes a second flexible board having insulating properties and extending along an upper surface of the sensor unit.

7. The measuring instrument according to claim 1 ,
wherein the front surface of the signal electrode is covered with an insulating material.

8. The measuring instrument according to claim 7 ,
wherein the insulating material covering the front surface of the signal electrode is made of borosilicate glass or quartz.

9. The measuring instrument according to claim 1 ,
wherein the at least one sensor chip is a plurality of sensors, and
the plurality of sensors is arranged at equal intervals along an edge of the base board all around the edge.

10. The measuring instrument according to claim 1 ,
wherein the at least one sensor chip is a plurality of sensors, and
the plurality of sensors is provided along an edge on a top surface of the base board.

11. The measuring instrument according to claim 1 ,
wherein the at least one sensor chip is a plurality of sensors, and
a front end surface of each of the plurality of sensors is along a side surface of the base board.

12. The measuring instrument according to claim 1 further comprising:
a plurality of bottom sensors provided along an edge on a bottom surface of the base board.

13. The measuring instrument according to claim 12 ,
wherein the at least one sensor chip is a plurality of sensors, and
each of the plurality of sensors and each of the plurality of bottom sensors are alternately arranged at intervals of 60° in a circumferential direction.

14. 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.

Assignees

• Tokyo Electron Ltd

Inventors

• Hatanaka Takayuki
• Yokoyama Kimihiro

Classifications

• H01J37/32917 Primary

  Plasma diagnostics · CPC title

• H01J2237/24564

  Measurements of electric or magnetic variables, e.g. voltage, current, frequency · CPC title

• G01B7/30

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• G01B7/001

  Constructional details of gauge heads (G01B7/012 takes precedence) · CPC title

• G01R29/12

  Measuring electrostatic fields {or voltage-potential} · CPC title