Patent ID: 12222379

DETAILED DESCRIPTION

Hereinafter, various exemplary embodiments will be described.

In one exemplary embodiment, a measuring instrument is provided. 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. 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. A space between the second ground electrode and the sensor unit is filled with an insulating material.

In the measuring instrument of the above embodiment, a rear side of the signal electrode is shielded by the guard electrode and the first ground electrode, and a lower side of the signal electrode is shielded by the second ground electrode. Therefore, according to the at least one sensor chip, it is possible to measure the electrostatic capacitance with high directivity in a specific direction, that is, in a direction in which a front surface of the signal electrode faces. In addition, since ESD for the guard electrode is suppressed, the ESD suppresses the operational amplifier from being broken via the guard electrode.

In one exemplary embodiment, the guard electrode constituting the sensor unit may not include a portion extending along the lower surface of the sensor unit.

In one exemplary embodiment, 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 may be all curved surfaces in parallel to a curved surface along an outer periphery of the base board.

In one exemplary embodiment, the at least one sensor chip may include a first flexible board extending along the lower surface of the sensor unit and including the second ground electrode.

In one exemplary embodiment, the at least one sensor chip may include a second flexible board extending along an upper surface of the sensor unit.

In one exemplary embodiment, the front surface of the signal electrode may be covered with an insulating material having insulating properties.

In one exemplary embodiment, the insulating material covering the front surface of the signal electrode may be made of borosilicate glass or quartz.

Hereinafter, various embodiments will be described in detail with reference to the drawings. The same reference numerals will be given to the same or corresponding parts in each drawing.

The measuring instrument according to one exemplary embodiment can be transported by a processing system1that has a function as a transport system S1. First, a processing system that includes a processing device for processing a workpiece and a transport device for transporting the workpiece to the processing device will be described.FIG.1is a diagram illustrating a processing system. The processing system1includes tables2ato2d, containers4ato4d, a loader module LM, an aligner AN, a load lock modules LL1and LL2, a process modules PM1to PM6, a transfer module TF, and a controller MC. The number of tables2ato2d, the number of containers4ato4d, the number of load lock modules LL1and LL2, and the number of process modules PM1to PM6are not limited, and any number of equal to or greater than one can be used.

The tables2ato2dare arranged along one edge of the loader module LM. The containers4ato4dare mounted on the tables2ato2d, respectively. Each of the containers4ato4dis, for example, a container called a front opening unified pod (FOUP). Each of the containers4ato4dcan be configured to accommodate the workpiece W. The workpiece W has a substantially disc shape like a wafer.

Inside of the loader module LM, there is a chamber wall that defines a transport space under atmospheric pressure. A transport device TU1is provided in this transport space. The transport device TU1is, for example, an articulated robot and is controlled by the controller MC. The transport device TU1is configured to transport the workpiece W between the containers4ato4dand the aligner AN, between the aligner AN and the load lock modules LL1to LL2, and between the load lock modules LL1to LL2and the containers4ato4d.

The aligner AN is connected to the loader module LM. The aligner AN is configured to adjust the position of the workpiece W (calibrate the position).FIG.2is a perspective view illustrating an aligner. The aligner AN includes a support stand6T, a drive device6D, and a sensor6S. The support stand6T is a stand that can rotate around the axis extending in the vertical direction. The support stand6T is configured to support the workpiece W. The support stand6T is rotated by the drive device6D. The drive device6D is controlled by the controller MC. When the support stand6T is rotated due to the power from the drive device6D, the workpiece W placed on the support stand6T is also rotated.

The sensor6S is an optical sensor. The sensor6S detects the edge of the workpiece W while the workpiece W is rotated. From the result of detecting the edge, the sensor6S detects an amount of deviation of an angle position of a notch WN (or another marker) of the workpiece W with respect to a reference angle position and an amount of deviation of a center position of the workpiece W with respect to the reference position. The sensor6S outputs the amount of deviation of the angle position of the notch WN and the amount of deviation of the center position of the workpiece W to the controller MC. The controller MC calculates an amount of rotation of the support stand6T for correcting the angle position of the notch WN to the reference angle position based on the amount of deviation of the angle position of the notch WN. The controller MC controls the drive device6D to rotate the support stand6T as much as the amount of rotation. In this way, the angle position of the notch WN can be corrected to the reference angle position. In addition, the controller MC controls a position of an end effector of the transport device TU1when receiving the workpiece W from the aligner AN based on the amount of deviation of the center position of the workpiece W. In this way, the center position of the workpiece W coincides with the predetermined position on the end effector of the transport device TU1.

Returning toFIG.1, each of the load lock module LL1and the load lock module LL2is provided between the loader module LM and the transfer module TF. Each of the load lock module LL1and the load lock module LL2provides a preliminary decompression chamber.

The transfer module TF is air-tightly connected to the load lock module LL1and the load lock module LL2via a gate valve. The transfer module TF provides a decompression chamber capable of reducing pressure. A transport device TU2is provided in this decompression chamber. The transport device TU2is, for example, an articulated robot having a transport arm TUa. The transport device TU2is controlled by the controller MC. The transport device TU2is configured to transport the workpiece W between the load lock modules LL1to LL2and the process modules PM1to PM6, and between any two process modules of the process modules PM1to PM6.

The process modules PM1to PM6are air-tightly connected to the transfer module TF via the gate valve. Each of the process modules PM1to PM6is a processing device configured to perform a dedicated process such as plasma processing on the workpiece W.

A series of operations when the processing on the workpiece W is performed in the processing system1will be illustrated as follows. The transport device TU1of the loader module LM takes out the workpiece W from any of the containers4ato4dand transports the workpiece W to the aligner AN. Subsequently, the transport device TU1takes out the position adjusted workpiece W from the aligner AN, and transports the workpiece W to one of the load lock module LL1and the load lock module LL2. Next, one load lock module reduces the pressure in the preliminary decompression chamber to a predetermined pressure. Next, the transport device TU2of the transfer module TF takes out the workpiece W from one of the load lock modules and transports the workpiece W to any of the process modules PM1to PM6. Then, one or more process modules among the process modules PM1to PM6perform processing on the workpiece W. Then, the transport device TU2transports the processed workpiece W from the process module to one of the load lock module LL1and the load lock module LL2. Next, the transport device TU1transports the workpiece W from one of the load lock modules to any of the containers4ato4d.

This processing system1includes the controller MC as described above. The controller MC can be a computer including a processor, a storage device such as a memory, a display device, an input/output device, a communication device, and the like. The series of operations of the processing system1described above are realized by controlling each part of the processing system1by the controller MC according to the program stored in the storage device.

FIG.3is a diagram illustrating an example of a plasma processing device that can be adopted as any of the process modules PM1to PM6. A plasma processing device10illustrated inFIG.3is a capacitance-coupling type plasma etching device. The plasma processing device10includes a chamber body12having a substantially cylindrical shape. The chamber body12is formed of, for example, aluminum, and the inner wall surface thereof may be anodized. This chamber body12is grounded for security.

A support portion14having a substantially cylindrical shape is provided on a bottom portion of the chamber body12. The support portion14is formed of, for example, an insulating material. The support portion14is provided in the chamber body12. The support portion14extends upward from the bottom portion of the chamber body12. In addition, a stage ST is provided in a chamber S provided by the chamber body12. The stage ST is supported by the support portion14.

The stage ST includes a lower electrode LE and an electrostatic chuck ESC. The lower electrode LE includes a first plate18aand a second plate18b. The first plate18aand the second plate18bare formed of a metal such as aluminum, and have a substantially disc shape. The second plate18bis provided on the first plate18aand is electrically connected to the first plate18a.

The electrostatic chuck ESC is provided on the second plate18b. The electrostatic chuck ESC has a structure in which an electrode, which is a conductive film, is disposed between a pair of insulating layers or insulating sheets, and has a substantially disc shape. A DC power supply22is electrically connected to the electrode of the electrostatic chuck ESC via a switch23. This electrostatic chuck ESC adsorbs the workpiece W by an electrostatic force such as a Coulomb force generated by a DC voltage from the DC power supply22. In this way, the electrostatic chuck ESC can hold the workpiece W.

An edge ring ER is provided on a peripheral edge of the second plate18b. This edge ring ER is provided to surround the edge of the workpiece W and the electrostatic chuck ESC. The edge ring ER has a first part P1and a second part P2(refer toFIG.7). The first part P1and the second part P2have an annular plate shape. The second part P2is a portion outside the first part P1. The second part P2has a larger thickness in the height direction than the first part P1. An inner edge P2iof the second part P2has a diameter larger than a diameter of an inner edge P1iof the first part P1. The workpiece W is mounted on the electrostatic chuck ESC so that the edge region is positioned on the first part P1of the edge ring ER. The edge ring ER can be formed of any of various materials such as silicon, silicon carbide, and silicon oxide.

A refrigerant flow path24is provided inside the second plate18b. The refrigerant flow path24constitutes a temperature control mechanism. Refrigerant is supplied to the refrigerant flow path24from a chiller unit provided outside the chamber body12via a pipe26a. The refrigerant supplied to the refrigerant flow path24is returned to the chiller unit via the pipe26b. As described above, the refrigerant is circulated between the refrigerant flow path24and the chiller unit. The temperature of the workpiece W supported by the electrostatic chuck ESC is controlled by controlling the temperature of this refrigerant.

A plurality of (for example, three) through holes25penetrating the stage ST are formed in the stage ST. The plurality of through holes25are formed inside the electrostatic chuck ESC in a plan view. A lift pin25ais inserted into each of the through holes25. InFIG.3, one through hole25into which one lift pin25ais inserted is drawn. The lift pin25ais provided to be vertically movable in the through hole25. When the lift pin25arises, the workpiece W supported on the electrostatic chuck ESC rises.

In the stage ST, a plurality of (for example, three) through holes27penetrating the stage ST (lower electrode LE) are formed at a position outside the electrostatic chuck ESC in a plan view. The lift pin27ais inserted into each of these through holes27. InFIG.3, one through hole27into which one lift pin27ais inserted is drawn. The lift pin27ais provided to be vertically movable in the through hole27. When the lift pin27arises, the edge ring ER supported on the second plate18brises.

In addition, a gas supply line28is provided in the plasma processing device10. The gas supply line28supplies heat transfer gas from a heat transfer gas supply mechanism, such as He gas, to a place between the upper surface of the electrostatic chuck ESC and the back surface of the workpiece W.

In addition, the plasma processing device10includes an upper electrode30. The upper electrode30is disposed above the stage ST to face the stage ST. The upper electrode30is supported on the upper portion of the chamber body12via an insulating shielding member32. The upper electrode30can include a top plate34and a support36. The top plate34faces the chamber S. The top plate34is provided with a plurality of gas discharge holes34a. The top plate34can be formed of silicon or quartz. Alternatively, the top plate34may be configured by forming a plasma resistant film such as yttrium oxide on the surface of the aluminum base material.

The support36detachably supports the top plate34. The support36may be formed of a conductive material such as aluminum. The support36can have a water-cooled structure. A gas diffusion chamber36ais provided inside the support36. A plurality of gas flow holes36bcommunicating with the gas discharge hole34aextend downward from this gas diffusion chamber36a. In addition, a gas introduction port36cfor guiding the processing gas into the gas diffusion chamber36ais formed in the support36. A gas supply pipe38is connected to the gas introduction port36c.

A gas source group40is connected to the gas supply pipe38via a valve group42and a flow rate controller group44. The gas source group40includes a plurality of gas sources for a plurality of types of gases. The valve group42includes a plurality of valves, and the flow rate controller group44includes a plurality of flow rate controllers such as mass flow controllers. The plurality of gas sources of the gas source group40are connected to the gas supply pipe38via the corresponding valve of the valve group42and the corresponding flow rate controller of the flow rate controller group44, respectively.

In addition, in the plasma processing device10, a depot shield46is detachably provided along the inner wall of the chamber body12. The depot shield46is also provided on the outer periphery of the support portion14. The depot shield46prevents etching by-products (depots) from adhering to the chamber body12. The depot shield46can be configured by covering an aluminum material with ceramics such as yttrium oxide.

An exhaust plate48is provided on the bottom portion side of the chamber body12, and between the support portion14and the side wall of the chamber body12. The exhaust plate48can be configured, for example, by covering an aluminum material with ceramics such as yttrium oxide. In the exhaust plate48, a plurality of holes penetrating in the thickness direction are formed. An exhaust port12eis provided below the exhaust plate48and on the chamber body12. An exhaust device50is connected to the exhaust port12evia an exhaust pipe52. The exhaust device50includes a vacuum pump such as a pressure regulating valve and a turbo molecular pump. The exhaust device50can reduce the pressure of the space in the chamber body12to a desired degree of vacuum. In addition, the side wall of the chamber body12is provided with a carry-inlet/outlet12gfor the workpiece W. The carry-inlet/outlet12gcan be opened and closed by a gate valve54.

In addition, the plasma processing device10further includes a first radio frequency power supply62and a second radio frequency power supply64. The first radio frequency power supply62is a power supply that generates a first radio frequency for the plasma generation. The first radio frequency power supply62generates, for example, a radio frequency having a frequency of 27 to 100 MHz. The first radio frequency power supply62is connected to the upper electrode30via a matcher66. The matcher66includes a circuit for matching an output impedance of the first radio frequency power supply62with an input impedance of the load side (upper electrode30side). The first radio frequency power supply62may be connected to the lower electrode LE via the matcher66.

The second radio frequency power supply64is a power supply that generates a second radio frequency for drawing ions into the workpiece W. The second radio frequency power supply64generates, for example, a radio frequency with a frequency in the range of 400 kHz to 13.56 MHz. The second radio frequency power supply64is connected to the lower electrode LE via a matcher68. The matcher68includes a circuit for matching an output impedance of the second radio frequency power supply64with an input impedance of the load side (lower electrode LE side).

In the plasma processing device10, gas from one or more gas sources selected from the plurality of gas sources is supplied to the chamber S. In addition, the pressure in the chamber S is set to a predetermined pressure by the exhaust device50. Further, the gas in the chamber S is excited by the first radio frequency from the first radio frequency power supply62. As a result, the plasma is generated. Then, the workpiece W is processed by the generated active species. If necessary, ions may be drawn into the workpiece W by a bias based on the second radio frequency from the second radio frequency power supply64.

The measuring instrument will be described below.FIG.4is a plan view illustrating an example of a measuring instrument as viewed from a top surface side.FIG.5is a plan view illustrating an example of the measuring instrument as viewed from a bottom surface side. The measuring instrument100illustrated inFIGS.4and5includes a base board102. The base board102is formed of, for example, silicon, and has a shape similar to a shape of the workpiece W, that is, a substantially disc shape. A diameter of the base board102is, for example, 300 mm, which is the same size as the diameter of the workpiece W. The shape and dimensions of the measuring instrument100are defined by the shape and dimensions of this base board102. Therefore, the measuring instrument100has a shape similar to the shape of the workpiece W and has the same dimensions as the workpiece W. In addition, a notch102N (or another marker) is formed on an edge of the base board102.

A plurality of first sensors104A to104C are provided on the base board102for measuring an electrostatic capacitance. The plurality of first sensors104A to104C are arranged at equal intervals along the edge of the base board102, for example, all around the edge. Specifically, each of the plurality of first sensors104A to104C is provided along the edge on the top surface side of the base board102. The front end surfaces of each of the plurality of first sensors104A to104C are along the side surface of the base board102.

In addition, a plurality of second sensors105A to105C for measuring an electrostatic capacitance are provided on the base board102. The plurality of second sensors105A to105C are arranged at equal intervals along the edge of the base board102, for example, all around the edge. Specifically, each of the plurality of second sensors105A to105C is provided along the edge on the bottom surface side of the base board. The signal electrode161of each of the plurality of second sensors105A to105C is along the bottom surface of the base board102. In addition, the second sensors105A to105C and the first sensors104A to104C are alternately arranged at intervals of 60° in the circumferential direction.

A circuit board106is provided in the center of the upper surface of the base board102. Wiring groups108A to108C are provided between the circuit board106and the plurality of first sensors104A to104C for electrically connecting each other. In addition, wiring groups208A to208C are provided between the circuit board106and the plurality of second sensors105A to105C for electrically connecting each other. The circuit board106, the wiring groups108A to108C, and the wiring groups208A to208C are covered with a cover103.

Hereinafter, the first sensor will be described in detail.FIG.6is a perspective view illustrating an example of the sensor.FIG.7is a sectional view taken along the line VII-VII inFIG.6.FIG.8is a sectional view of the first sensor, taken along the line VIII-VIII inFIG.7.FIG.9is a sectional view of the first sensor, taken along the line IX-IX inFIG.7.FIG.10is a sectional view of the first sensor, taken along the line X-X inFIG.7.

The first sensor (sensor chip)104is a sensor used as a plurality of first sensors104A to104C of the measuring instrument100, and is configured as a chip-shaped component. In the description below, the XYZ rectangular coordinate system will be referred to as appropriate. The X-direction indicates a front direction of the first sensor104, the Y-direction indicates a direction orthogonal to the X-direction and indicates the width direction of the first sensor104, and the Z-direction indicates a direction orthogonal to the X-direction and the Y-direction, and indicates an upward direction of the first sensor104.FIG.7illustrates the edge ring ER together with the first sensor104.

The first sensor104includes a sensor body140(sensor unit), a first flexible board146, and a second flexible board149. The sensor body140includes a signal electrode141, a guard electrode142, and a first ground electrode143. In one example, the sensor body140may be a micro electro mechanical system (MEMS) chip manufactured using a MEMS technology. For example, the signal electrode141, the guard electrode142, and the first ground electrode143can be formed of conductive materials such as copper and silicon.

The signal electrode141has a front surface141aintersecting a radial direction of the base board101. That is, the front surface141aof the signal electrode141in the measuring instrument100refers to a surface outside the base board in the radial direction. In one example, the front surface141aof the signal electrode141is curved along an outer periphery of the measuring instrument100. For example, the front surface141aof the signal electrode141has a constant curvature at any position of the front surface141a, and the curvature is a reciprocal number of a distance between the central axis AX100of the measuring instrument100and the front surface141a. A pad151electrically connected to the signal electrode141is provided on an upper end of a sensor body140.

The guard electrode142is disposed on a rear side of the signal electrode141while being spaced apart from the signal electrode141. In addition, the guard electrode142extends along the signal electrode141. As an example illustrated in the drawings, the guard electrode142includes an inner surface portion142acurved along the signal electrode141and a side edge portion142bsurrounding an edge of the signal electrode141in a width direction. An inner surface portion142aof the guard electrode142is curved like the signal electrode141. For example, the inner surface portion142aof the guard electrode142has a constant curvature at any position of the inner surface portion142a, and the curvature is a reciprocal number of a distance between the central axis AX100of the measuring instrument100and the inner surface portion142a. The side edge portions142bof the guard electrode142protrude forward from both ends of the inner surface portion142ain a width direction, respectively. The side edge portion142bis formed along the edge while being spaced apart from the edge of the signal electrode141in the width direction. A pad152electrically connected to the guard electrode142is provided on an upper end of the sensor body140.

The first ground electrode143is disposed on a rear side of the guard electrode142while being spaced apart from the guard electrode142. In addition, a front surface143aof the first ground electrode143extends along the guard electrode142. That is, the front surface143aof the first ground electrode143is curved parallel to the guard electrode142. For example, the front surface143aof the first ground electrode143has a constant curvature at any position of the front surface143a, and the curvature is a reciprocal number of a distance between the central axis AX100of the measuring instrument100and the front surface143a. In addition, the first ground electrode143includes a side edge portion143bsurrounding the side edge portion142bof the guard electrode142. The side edge portions143bof the first ground electrode143protrude forward from both ends of the front surface143ain a width direction, respectively. The side edge portion143bis formed along the side edge portion142bwhile being spaced apart from the side edge portion142bof the guard electrode142. A pad153electrically connected to the first ground electrode143is provided on an upper end of the sensor body140.

In addition, an insulating material145having electrical insulating properties is disposed between each of the signal electrode141, the guard electrode142, and the first ground electrode143, which are spaced apart from each other. As shown in the drawing, the insulating material145includes a front surface portion145a, a first intermediate portion145b, and a second intermediate portion145c. The front surface portion145aconstitutes the front surface of the sensor body140. That is, the front surface portion145acovers the front surface141aof the signal electrode141, a front portion of the side edge portion142bof the guard electrode142, and a front portion of the side edge portion143bof the first ground electrode143. The first intermediate portion145bis disposed between the signal electrode141and the guard electrode142. In the illustrated example, the first intermediate portion145bis also disposed between the pad151connected to the signal electrode141and the pad152connected to the guard electrode142. The second intermediate portion145cis disposed between the guard electrode142and the first ground electrode143. In the illustrated example, the second intermediate portion145cis also disposed between the pad152connected to the guard electrode142and the pad153connected to the first ground electrode143. The insulating material145may be made of, for example, borosilicate glass, quartz, or the like.

As described above, in a plan view, the front surface141aof the signal electrode141, the front surface (inner surface portion142a) of the guard electrode142, and the front surface143aof the first ground electrode143are all curved surfaces in parallel to a curved surface along an outer periphery of the base board101. In addition, the signal electrode141, the guard electrode142, and the first ground electrode143all extend from an upper end to a lower end of the sensor body140. The signal electrode141, the guard electrode142, and the first ground electrode143are disposed to be spaced apart from each other because the insulating material145extending from the upper end to the lower end of the sensor body140is interposed therebetween.

The first flexible board146extends along the lower surface of the sensor body140having a column shape. For example, the first flexible board146is fixed to the lower surface of the sensor body140by an adhesive member such as an adhesive having electrical insulating properties or an adhesive sheet. Thus, the lower surface of the sensor body140is electrically insulated from the outside. In addition, the first flexible board146includes a region having a planar shape similar to that of the sensor body140, and a terminal region146aprotruding from the center of the rear end of the region to the rear side. An example of the first flexible board146includes a board body147and a second ground electrode148. The board body147is formed of, for example, polyimide or the like having electrical insulating properties. The second ground electrode148is formed in a plate shape slightly smaller than the board body147and is covered with the board body147. That is, the upper surface, lower surface and side surfaces of the second ground electrode148are all covered with the board body147. The second ground electrode148may be formed of, for example, a conductive metal such as copper.

The second ground electrode148extends along the lower surface of the sensor body140. Therefore, a space between the second ground electrode148and the sensor body140is filled only with the board body147having electrical insulating properties. The terminal region146ais formed with an opening147ain the board body147, and has a part of the second ground electrode148exposed as a pad148a. In addition, the terminal region146ais formed with a pad146cand a pad146dcorresponding to the signal electrode141and the guard electrode142, respectively.

The second flexible board149has a planar shape similar to that of the sensor body140and extends along the upper surface of the sensor body140. An example of the second flexible board149is formed of, for example, polyimide or the like having electrical insulating properties. Openings149acorresponding to the pads151to153are formed in the second flexible board149, so that the pads151to153are exposed to the outside. The second flexible board149may be fixed to the upper surface of the sensor body140by an adhesive member such as an adhesive having electrical insulating properties or an adhesive sheet. In this case, the upper surface of sensor body140is electrically insulated from the outside.

When the first sensor104is used as a sensor of the measuring instrument100, as will be described later, the signal electrode141is connected to a wiring181, the guard electrode142is connected to a wiring182, and the first ground electrode143is connected to a wiring183. In one example, the wiring connected to the pad151of the signal electrode141may be connected to the wiring181via the pad146c. In addition, the wiring connected to the pad152of the guard electrode142may be connected to the wiring182via the pad146d. In addition, the wiring connected to the pad153of the first ground electrode143may be connected to the wiring183via the pad148aof the second ground electrode148.

Hereinafter, the second sensor will be described in detail. FIG.11is a partially enlarged view ofFIG.5, and illustrates one second sensor. The second sensor105includes a signal electrode161. An edge of the signal electrode161has partially an arc shape. That is, the signal electrode161has a planar shape defined by an inner edge161aand an outer edge161b, which are two arcs having different radii with the central axis AX100as a center. The outer edge161bat the outside in the radial direction of each signal electrode161of the plurality of second sensors105A to105C extends on a common circle. In addition, the inner edge161aat the inner side in the radial direction of each signal electrode161of the plurality of second sensors105A to105C extends on another common circle. The curvature of a part of the edge of the signal electrode161coincides with the curvature of the edge of the electrostatic chuck ESC. In an exemplary embodiment, the curvature of the outer edge161bforming the edge at the outside in the radial direction of the signal electrode161coincides with the curvature of the edge of the electrostatic chuck ESC. The center of curvature of the outer edge161b, that is, the center of the circle on which the outer edge161bextends, shares the central axis AX100.

In an exemplary embodiment, the second sensor105further includes a guard electrode162that surrounds the signal electrode161. The guard electrode162has a frame shape and surrounds the signal electrode161over the entire circumference. The guard electrode162and the signal electrode161are spaced apart from each other so that an insulating region164is interposed therebetween. In addition, in an exemplary embodiment, the second sensor105further includes an electrode163that surrounds the guard electrode162at the outside of the guard electrode162. The electrode163has a frame shape and surrounds the guard electrode162over the entire circumference. The guard electrode162and the electrode163are spaced apart from each other so that an insulating region165is interposed therebetween.

Hereinafter, the configuration of the circuit board106will be described.FIG.12is a diagram illustrating a configuration of a circuit board of the measuring instrument. The circuit board106includes a radio frequency oscillator171, a plurality of C/V conversion circuits172A to172C, a plurality of C/V conversion circuits272A to272C, A/D converter173, a processor174, a storage device175, a communication device176, and a power supply177. In an example, the arithmetic device is configured with the processor174, the storage device175, and the like. In addition, the circuit board106includes a temperature sensor179. The temperature sensor179outputs a signal corresponding to the measured temperature to the processor174. For example, the temperature sensor179can acquire the temperature of the environment around the measuring instrument100.

Each of the plurality of first sensors104A to104C is connected to the circuit board106via the corresponding wiring group among the plurality of wiring groups108A to108C. In addition, each of the plurality of first sensors104A to104C is connected to the corresponding C/V conversion circuit among the plurality of C/V conversion circuits172A to172C via a couple of wirings included in the corresponding wiring group. Each of the plurality of second sensors105A to105C is connected to the circuit board106via the corresponding wiring group among the plurality of wiring groups208A to208C. In addition, each of the plurality of second sensors105A to105C is connected to the corresponding C/V conversion circuit among the plurality of C/V conversion circuits272A to272C via a couple of wirings included in the corresponding wiring group. Hereinafter, one first sensor104having the same configuration as each of the first sensors104A to104C, one wiring group108having the same configuration as each of the wiring groups108A to108C, and one C/V conversion circuit172having the same configuration as each of the C/V conversion circuits172A to172C, will be described. In addition, one second sensor105having the same configuration as each of the second sensors105A to105C, one wiring group208having the same configuration as each of the wiring groups208A to208C, and one C/V conversion circuit272having the same configuration as each of C/V conversion circuits272A to272C, will be described.

The wiring group108includes wirings181to183. One end of the wiring181is electrically connected to the pad151connected to the signal electrode141, and the other end of the wiring181is connected to the C/V conversion circuit172. In addition, one end of the wiring182is electrically connected to the pad152connected to the guard electrode142, and the other end of the wiring182is connected to the C/V conversion circuit172. In addition, one end of the wiring183is electrically connected to the pad153which is electrically connected to the first ground electrode143and the second ground electrode148. The wiring183is connected to a ground potential line GL connected to a ground G of the circuit board106. The wiring183may be connected to the ground potential line GL via a switch SWG.

The wiring group208includes wirings281to283. In addition, one end of the wiring281is electrically connected to the signal electrode161, and the other end of the wiring281is connected to the C/V conversion circuit272. In addition, one end of the wiring282is electrically connected to the guard electrode162, and the other end of the wiring282is connected to the C/V conversion circuit272. In addition, one end of the wiring283is connected to the electrode163. The wiring283is electrically connected to the ground potential line GL connected to the ground GC of the circuit board106. The wiring283may be connected to the ground potential line GL via the switch SWG.

The radio frequency oscillator171is connected to the power supply177such as a battery, and is configured to receive power from the power supply177to generate a radio frequency signal. The power supply177is also connected to the processor174, the storage device175, and the communication device176. The radio frequency oscillator171includes a plurality of output lines. The radio frequency oscillator171applies the generated radio frequency signal to the wiring181and the wiring182, and to the wiring281and the wiring282via the plurality of output lines. Therefore, the radio frequency oscillator171is electrically connected to the signal electrode141and the guard electrode142of the first sensor104, and the radio frequency signal from the radio frequency oscillator171is applied to the signal electrode141and the guard electrode142. In addition, the radio frequency oscillator171is electrically connected to the signal electrode161and the guard electrode162of the second sensor105, and the radio frequency signal from the radio frequency oscillator171is applied to the signal electrode161and the guard electrode162.

The wiring181connected to the pad151and the wiring182connected to the pad152are connected to the input of the C/V conversion circuit172. That is, the guard electrode142and the signal electrode141of the first sensor104are connected to the input of the C/V conversion circuit172. In addition, each of the signal electrode161and the guard electrode162is connected to the input of the C/V conversion circuit272. The C/V conversion circuit172and the C/V conversion circuit272are configured to generate a voltage signal having an amplitude corresponding to the potential difference at the input, and output the voltage signal. The C/V conversion circuit172generates a voltage signal corresponding to the electrostatic capacitance formed by the corresponding first sensor104. That is, as the electrostatic capacitance of the signal electrode connected to the C/V conversion circuit172increases, the magnitude of the voltage of the voltage signal output from the C/V conversion circuit172increases. Similarly, as the electrostatic capacitance of the signal electrode connected to the C/V conversion circuit272increases, the magnitude of the voltage of the voltage signal output from the C/V conversion circuit272increases.

Connections between the radio frequency oscillator171and the wiring181and between the wiring182and the C/V conversion circuit172will be described in more detail.FIG.11is a circuit diagram illustrating connections between the radio frequency oscillator171and the wiring181and between the wiring182and the C/V conversion circuit172. As illustrated inFIG.13, a resistor171ais connected between the radio frequency oscillator171and the wiring182. A phase adjustment circuit171dincluding a variable resistor171band a variable capacitor171cis connected between the radio frequency oscillator171and the wiring181. The C/V conversion circuit172has an amplifier circuit172aincluding an operational amplifier and a resistor as part thereof. In the amplifier circuit172a, the wiring181is input to an inversion input of the operational amplifier, and the wiring182is input to a non-inversion input of the operational amplifier. In addition, the non-inversion input and the output of the operational amplifier are connected via the resistor. The amplifier circuit172aamplifies a potential difference between the signal from the signal electrode141input to the C/V conversion circuit172and the signal from the guard electrode142.

The radio frequency oscillator171and the wiring281and the wiring282and the C/V conversion circuit272are connected in the same manner as the radio frequency oscillator171and the wiring181and the wiring182and the C/V conversion circuit172, respectively. That is, a resistor is connected between the radio frequency oscillator171and the wiring282. A variable impedance circuit including a variable resistor and a variable capacitor is connected between the radio frequency oscillator171and the wiring281. The C/V conversion circuit272has an amplifier circuit including an operational amplifier and a resistor as part thereof. In the amplifier circuit, the wiring281is input to the inversion input of the operational amplifier, and the wiring282is input to the non-inversion input of the operational amplifier. In addition, the non-inversion input and the output of the operational amplifier are connected via the resistor.

In the circuit configuration as described above, the amplitude of the signal from the signal electrode141can be changed by changing a resistance value of the variable resistor171bof the phase adjustment circuit171d. In addition, the phase of the signal from the signal electrode141can be changed by changing an electrostatic capacitance value of the variable capacitor171cof the phase adjustment circuit171d. In one exemplary embodiment, the processor174adjusts (controls) the resistance value of variable resistor171band the electrostatic capacitance value of the variable capacitor171cto adjust an admittance of the phase adjustment circuit171d.

For example, as so-called zero point adjustment, the processor174may adjust the resistance value of the variable resistor171band the capacity of the variable capacitor171cin the phase adjustment circuit171dso that the voltage signal output from the C/V conversion circuit172becomes zero. In addition, the resistance value of the variable resistor171band the capacity of the variable capacitor171cin the phase adjustment circuit171dmay be adjusted so that the voltage signal output from the C/V conversion circuit272becomes zero.

The outputs of the C/V conversion circuit172and the C/V conversion circuit272are connected to the input of the A/D converter173. In addition, the A/D converter173is connected to the processor174. The A/D converter173is controlled by the control signal from the processor174, converts the output signal (voltage signal) of the C/V conversion circuit172and the output signal (voltage signal) of the C/V conversion circuit272into digital values, and outputs the results to the processor174as detection values.

The storage device175is connected to the processor174. The storage device175is a storage device such as a volatile memory, and is configured to store measurement data, for example. In addition, another storage device178is connected to the processor174. The storage device178is a storage device such as a non-volatile memory, and stores, for example, a program read and executed by the processor174.

The communication device176is a communication device compliant with any wireless communication standard. For example, the communication device176is compliant with Bluetooth®. The communication device176is configured to wirelessly transmit the measurement data stored in the storage device175.

The processor174is configured to control each part of the measuring instrument100by executing the program described above. For example, the processor174controls the supply of the radio frequency signals from the radio frequency oscillator171to the guard electrode142, the signal electrode141, the signal electrode161, and the guard electrode162. In addition, the processor174controls the supply of the power from the power supply177to the storage device175, the supply of the power from the power supply177to the communication device176, and the like. Furthermore, the processor174acquires the measurement value of the first sensor104and the measurement value of the second sensor105based on the detection value input from the A/D converter173by executing the program described above. In an embodiment, when the detection value output from the A/D converter173is X, in the processor174, the measurement value is acquired based on the detection value such that the measurement value becomes proportional to (a·X+b). Here, a and b are constants that change depending on the state of the circuit, and the like. The processor174may have, for example, a predetermined arithmetic expression (function) such that the measurement value becomes a value proportional to (a·X+b).

In the measuring instrument100as described above, in a state in which the measuring instrument100is disposed in a region surrounded by the edge ring ER, a plurality of signal electrodes141and the guard electrodes142face an inner edge of the edge ring ER. The measurement value generated based on the potential difference between the signal of the signal electrode141and the signal of the guard electrode142represents the electrostatic capacitance that reflects the distance between each of the plurality of signal electrodes141and the edge ring ER. The electrostatic capacitance C is represented by C=εS/d. ε is a dielectric constant of a medium between the front surface141aof the signal electrode141and the inner edge of the edge ring ER, S is an area of the front surface141aof the signal electrode141, and d is a distance between the front surface141aof the signal electrode141and the inner edge of the edge ring ER.

Therefore, according to the measuring instrument100, measurement data that reflects the relative positional relationship between the measuring instrument100imitating the workpiece W and the edge ring ER can be obtained. For example, the plurality of measurement values acquired by the measuring instrument100become smaller as the distance between the front surface141aof the signal electrode141and the inner edge of the edge ring ER becomes larger. Therefore, an amount of deviation of each signal electrode141in each radial direction of the edge ring ER can be obtained based on the measurement value representing the electrostatic capacitance of each signal electrode141of the first sensors104A to104C. Then, an error of the transport position of the measuring instrument100can be obtained from the amount of deviation of each signal electrode141of the first sensors104A to104C in each radial direction.

In addition, in a state in which the measuring instrument100is mounted on the electrostatic chuck ESC, a plurality of signal electrodes161and the guard electrodes162face the electrostatic chuck ESC. As described above, the electrostatic capacitance C is represented by C=εS/d. ε is a dielectric constant of a medium between the signal electrode161and the electrostatic chuck ESC, d is a distance between the signal electrode161and the electrostatic chuck ESC, and S is an area in which the signal electrode161and the electrostatic chuck ESC overlap each other in a plan view. The area S changes depending on a relative positional relationship between the measuring instrument100and the electrostatic chuck ESC. Therefore, according to the measuring instrument100, the measurement data that reflects the relative positional relationship between the measuring instrument100imitating the workpiece W and the electrostatic chuck ESC can be obtained.

In an example, when the measuring instrument100is transported to a predetermined transport position, that is, a position on the electrostatic chuck ESC where the center of the electrostatic chuck ESC coincides with the center of the measuring instrument100, the outer edge161bof the signal electrode161and the edge of the electrostatic chuck ESC may coincide with each other. In this case, for example, since the transport position of the measuring instrument100is deviated from the predetermined transport position, when the signal electrode161is deviated outward in the radial direction with respect to the electrostatic chuck ESC, the area S decreases. That is, the electrostatic capacitance measured by the signal electrode161becomes smaller than the electrostatic capacitance when the measuring instrument100is transported to the predetermined transport position. Therefore, the amount of deviation of each signal electrode161of the electrostatic chuck ESC in each radial direction can be obtained based on the measurement value representing the electrostatic capacitance of each signal electrode161of the second sensors105A to105C. Then, an error of the transport position of the measuring instrument100can be obtained from the amount of deviation of each signal electrode161of the second sensors105A to105C in each radial direction.

As described above, the measuring instrument100includes the disc-shaped base board101, the first sensor104provided on the base board101, and the circuit board106provided on the base board101. The first sensor104has the sensor body140including the signal electrode141, the guard electrode142, and the first ground electrode143. The signal electrode141has the front surface intersecting the base board101in the radial direction. The guard electrode142is disposed on the rear side of the signal electrode141while being spaced apart from the signal electrode141, and extends along the signal electrode141. The first ground electrode143is disposed on the rear side of the guard electrode142. The circuit board106includes the radio frequency oscillator171provided to apply the radio frequency signal to each of the signal electrode141and the guard electrode142, and the C/V conversion circuit172configured to generate the voltage signal according to the electrostatic capacitance formed by the signal electrode141. The C/V conversion circuit172has the amplifier circuit172aincluding the operational amplifier. The radio frequency oscillator171is connected to the non-inversion input terminal of the operational amplifier so that the radio frequency signal applied to the signal electrode141is input to the non-inversion input terminal. In addition, the radio frequency oscillator171is connected to the inversion input terminal of the operational amplifier so that the radio frequency signal applied to the signal electrode141is input to the inversion input terminal. The first sensor104includes the second ground electrode148extending along the lower surface of the sensor body140. The signal electrode141, the guard electrode142, and the first ground electrode143of the sensor body140all extend to the lower end of the sensor body140. The space between the second ground electrode148and the sensor body140is filled with the insulating material. The space may be filled only with the insulating material.

In the measuring instrument100of the above embodiment, the rear side of the signal electrode141is shielded by the guard electrode142and the first ground electrode143, and the lower side of the signal electrode141is shielded by the second ground electrode148. Therefore, according to the first sensor104, it is possible to measure the electrostatic capacitance with high directivity in a specific direction, that is, in the direction in which the front surface of the signal electrode141faces.

For example, it is conceivable to dispose the guard electrode on the lower side of the sensor body140in order to increase the shielding performance against the lower side of the sensor body140. However, when the guard electrode extends along the lower surface of the sensor body140, the operational amplifier may be broken by the ESD via the guard electrode. In one exemplary embodiment, no guard electrode is disposed on the lower side of the sensor body140, and the guard electrode142constituting the sensor body140does not include a portion extending along the lower surface of the sensor body140. That is, since the space between the second ground electrode148and the sensor body140is filled only with the insulating material, the ESD suppresses the operational amplifier from being broken via the guard electrode.

In one exemplary embodiment, in a plan view, the front surface of the signal electrode141, the front surface of the guard electrode142, and the front surface of the first ground electrode143may be all curved surfaces in parallel to a curved surface formed by the outer periphery of the base board101. In this configuration, each of the signal electrode, guard electrode, and first ground electrode is also disposed in parallel to the edge ring. Therefore, it is possible to obtain a measurement value showing an accurate distance from the edge ring.

In one exemplary embodiment, the first sensor104may include the first flexible board146having insulating properties, extending along the lower surface of the sensor body140, and including the second ground electrode148. With this configuration, the second ground electrode148can be easily disposed on the lower side of the sensor body140.

In one exemplary embodiment, the first sensor104may include the second flexible board149having insulating properties and extending along the upper surface of the sensor body140. With this configuration, insulating properties on the upper surface of the sensor body140can be secured.

In one exemplary embodiment, the front surface141aof the signal electrode141is covered with the insulating material145having electrical insulating properties. In this configuration, the ESD suppresses the operational amplifier from being broken via the signal electrode141.

From the foregoing description, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the aspects following claims.