Wireless capacitive gapping sensor with unibody substrate and process of implementing the same

Abstract

A wafer-shaped capacitive gapping sensor that may include one or more capacitance sensors and a monolithic housing body, an active shield, and / or a controller that is configured to drive a first one of the capacitance sensors either simultaneously with or differently from a second one of the capacitance sensors. The monolithic housing body may be configured to separate analog circuitry of the one or more capacitance sensors and a digital or other electrical component (e.g., a controller and / or a battery) from one another. For example, the analog circuitry may be disposed within a front facing cavity and the controller and battery may be disposed within a rear facing cavity or separated from the front facing cavity by a stiffening rib. The active shield may include an active shield member that defines a non-circular inner perimeter that that a respective one of the one or more capacitance sensors is disposed within.

Description

WIRELESS CAPACITIVE GAPPING SENSOR WITH UNIBODY SUBSTRATE ANDPROCESS OF IMPLEMENTING THE SAMECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 657,632, filed June 7, 2024, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The disclosure relates generally to proximity sensors and semiconductor processing tools, more particularly, wafer-shaped non-contact capacitive gapping sensor systems that may be configured to measure spacing and / or orientation of a semiconductor processing tool (e.g., a showerhead of a semiconductor processing apparatus).BACKGROUND

[0003] Semiconductor processing systems often require clean environments and precise semiconductor wafer movement. Often, high-precision robotic systems and / or front opening unified pods (FOUP) are utilized to move substrates, such as semiconductor wafers, between various processing stations within a semiconductor processing system with requisite cleanliness and precision.

[0004] Some wafer-like sensors in the form of a wafer can be moved through the semiconductor processing system to wirelessly convey information within the semiconductor system. As used herein, “wafer-like” is intended to mean a sensor in the form of a semiconductor wafer. Of these wireless wafer-like sensors, some of which include additional types of detectors, allow the wafer-like sensors to measure a host of internal conditions within the processing environment of the semiconductor processing system.

[0005] Wireless wafer-like sensors enable measurements to be made at various points throughout the processing environment with reduced disruption of the internal environment as well as reduced disturbance of the wafer handling mechanisms and fabrication processes (e.g., baking, etching, physical vapor deposition, chemical vapor deposition, coating, rinsing, drying, etc.). For example, the wireless wafer-like sensor does not require that a vacuum chamber be vented or pumped down; nor does it pose any higher contamination risk to an ultra-clean environment than is otherwise suffered during normal processing. The wireless wafer-like sensor form factor enables measurements of process conditions with minimal observational uncertainty.

[0006] For example, CyberOptics’s WaferSense® Auto Gapping System™ (AGS) provides a wireless wafer-shaped sensor. The CyberOptics’s WaferSense® AGS measures gaps using capacitive sensing technology to measure a distance to a target object (e.g., a conductive electrode, such as a showerhead) to return real-time gap measurements that display in numerical and graphical form on a laptop or PC. Since the gapping tool is wireless and wafer-like, it can be handled automatically to speed up equipment setup and maintenance. More accurate measurements may provide for improved uniformity and accurate positioning of the showerhead, which is a critical factor in the uniformity7of many dielectric films. For example, showerheads that are not parallel to the wafer platen yield non-uniform deposition films. Non-uniform deposition can lead to reduced yield depending on the application and device.

[0007] The wafer-shaped sensors may require significant weight and thickness to meet appropriate strength and / or rigidity7requirements for calibrating of a showerhead. Moreover, the sensitivity and precision of the capacitance sensors may be limited relative to larger capacitance proximity sensors that are too large or otherwise not suitable for a semiconductor environment (e.g., due to the shape and size requirements of the wafer-shaped sensors).SUMMARY

[0008] The present application provides for a wafer-shaped capacitive gapping sensor that may include one or more capacitance sensors and a monolithic housing body, an active shield, and / or a controller that is configured to drive a first one of the capacitance sensors either simultaneously with or differently from a second one of the capacitance sensors. The monolithic housing body may be configured to separate analog circuitry of the one or more capacitance sensors and a digital or other electrical component (e.g., a controller and / or a battery) from one another. For example, the analog circuitry7may be disposed within a front facing cavity and the controller and battery7may be disposed within a rear facing cavity7or separated from the front facing cavity by a stiffening rib. The active shield may include an active shield member that defines a non-circular inner perimeter that that a respective one of the one or more capacitance sensors is disposed within.

[0009] The single-piece monolithic design may provide for minimizing of the number of parts required to assemble, streamlining assembly, reducing manufacturing complexity7, reducing weight, reducing overall thickness, and / or the like. The monolithic housing body may provide for shielding sensitive analog components of the capacitance sensors from digital electronics, which may7thus minimize electrical interference, lower a noise floor, increase signal integrity7, and / or the like.

[0010] The controller may be configured to operate in one or more of several modes. For example, in a first mode the controller may be configured to drive the first one of the capacitance sensors simultaneously with at least a second one of the capacitance sensors. Driving two or more capacitance sensors simultaneously may provide for increased sensitivity compared to driving only one sensor at a time. In the first mode, the controller may be configured to drive every capacitance sensor of a capacitive gapping sensor system.

[0011] In a second mode, the controller may be configured to drive the first one of the capacitance sensors differently from at least the second one of the capacitance sensors. For example, the controller may be configured to drive two of the capacitance sensors simultaneously in the same phase, while driving another one of the capacitance sensors in a different phase (e.g., phase shifted by 180°). Driving in a different phase may provide for reducing external influences, such as electrical noise, from measurements made by the capacitance sensors.

[0012] The one or more capacitance sensors may include three or more capacitance sensors. The controller may be configured to operate three or more sensors (or sets of sensors), such that an orientation of the target object may be determined.

[0013] In the first or second modes, the controller may be configured to operate in several stages. For example, during a first stage the controller may be configured to drive a first pair of the capacitance sensors simultaneously in the same phase, while driving another of the capacitance sensors differently (e.g., at 0 V). During a second stage, the controller may be configured to drive a second pair of the capacitance sensors simultaneously in the same phase, while driving one of the capacitance sensors of the first pair of the capacitance sensors differently (e.g., at 0 V). During a third stage, the controller may be configured to drive a second pair of the capacitance sensors simultaneously in the same phase, while driving one of the capacitance sensors of the first pair of the capacitance sensors differently (e.g., at 0 V).

[0014] If more than three capacitance sensors are provided, additional stages may be utilized. Additionally or alternatively, sets of more than two capacitance sensors may be driven simultaneously during respective phases and / or more than one capacitance sensor may be driven differently.

[0015] Thus, the capacitance sensors can be electrically driven utilizing various schemes based on the application and required performance optimization criteria. For example, a push-pull mode and / or a simultaneous mode (utilizing more than one probe or sensor for measurement) that may increase sensitivity. Also, the controller may adapt driving characteristics for the capacitance sensors and / or the active shield based on measurementconditions, anywhere from 0 V to the probe’s and / or active shield’s maximum amplitude. For example, each capacitance probe may have its own capacitance sensor driver and receiver circuitry including an analog-to-digital converter mounted directly underneath the capacitance probe.

[0016] According to an embodiment of the present disclosure, a non-contact capacitive gapping sensor system may comprise a housing that includes a monolithic housing body that defines a front end and a rear end that is offset from the front end. The non-contact capacitive gapping sensor system may comprise a capacitance sensor that comprises a capacitive sensor plate that is configured to emit a first electric field, wherein the monolithic housing body defines a sensor cavity at the front end, and wherein the capacitance sensor is disposed within the sensor cavity such that the capacitance sensor is directed along a forward direction away from the front end and the rear end.

[0017] According to another embodiment of the present disclosure, a non-contact capacitive gapping sensor system may comprise a housing and a capacitance sensor. The capacitance sensor may comprise a capacitive sensor plate configured to emit a first electric field upon being driven at a first amplitude. The non-contact capacitive gapping sensor system may comprise an active shield member that is configured to emit a second electric field such that first electric field is directed toward a target object upon the active shield member being driven at a second amplitude, wherein the active shield member defines a space that the capacitive sensor plate is disposed within. The non-contact capacitive gapping sensor system may comprise a controller that is configured to drive the active shield member and the capacitive sensor plate, wherein the controller is configured to drive the active shield member at the second amplitude and is configured to drive the capacitive sensor plate at the first amplitude, and wherein the controller is configured to adjust the second amplitude relative to the first amplitude.

[0018] According to another embodiment of the present disclosure, a non-contact capacitive gapping sensor system may comprise a housing and a first capacitance sensor. The first capacitance sensor may comprise a first capacitive sensor plate configured to emit a first electric field upon being driven. The non-contact capacitive gapping sensor system may comprise a second capacitance sensor. The second capacitance sensor may comprise a second capacitive sensor plate configured to emit a second electric field upon being driven. The noncontact capacitive gapping sensor system may comprise a controller that in a first mode is configured to drive the first capacitive sensor plate differently from the second capacitive sensor plate.

[0019] According to another embodiment of the present disclosure, a non-contact capacitive gapping sensor system may comprise a housing and a first capacitance sensor. The first capacitance sensor may comprise a first capacitive sensor plate configured to emit a first electric field upon being driven. The non-contact capacitive gapping sensor system may comprise a second capacitance sensor. The second capacitance sensor may comprise a second capacitive sensor plate configured to emit a second electric field upon being driven. The noncontact capacitive gapping sensor system may comprise a controller that in a first mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously.

[0020] Features of any of the above embodiments may be combinable with one another in their entirety or in part. For example, a capacitance gapping sensor system may include the monolithic housing body, the active shield member, the controller that is configured to operate a capacitive sensor plate differently from another capacitive sensor plate in one mode, and / or the controller that is configured to operate multiple capacitive sensor plates simultaneously in another mode.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The foregoing summary, as well as the following detailed description of illustrative embodiments of the capacitive gapping sensor system of the present application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the capacitive gapping sensor system of the present application, there is shown in the drawings illustrative embodiments. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0022] Fig. 1 is a schematic view of a capacitive gapping sensor system and a target object.

[0023] Fig. 2 is a schematic view of one of the capacitive gapping sensors of the capacitive gapping sensor system of Fig. 1.

[0024] Fig. 3 is a schematic view of circuitry of the capacitive gapping sensor of Fig. 2.

[0025] Fig. 4 is a schematic view of a push-pull driving mode for the capacitive gapping sensor system of Fig. 1.

[0026] Fig. 5 is a schematic view of a simultaneous driving mode for at least two capacitive gapping sensors of the capacitive gapping sensor system of Fig. 1.

[0027] Fig. 6 is an oblique front view of the capacitive gapping sensor system of Fig. 1 .

[0028] Fig. 7 is a front elevation view of the capacitive gapping sensor system of Fig.

[0029] Fig. 8 is an oblique rear view of the capacitive gapping sensor system of Fig. 6.

[0030] Fig. 9 is a side elevation view of the capacitive gapping sensor system of Fig. 6.

[0031] Fig. 10 is an oblique front cross-sectional view of the capacitive gapping sensor system of Fig. 6.

[0032] Fig. 11 is an oblique front view of one of the capacitive gapping sensors of the capacitive gapping sensor system of Fig. 6.

[0033] Fig. 12 is a front elevation view of the capacitive gapping sensor of Fig. 11.

[0034] Fig. 13 is a rear elevation view of the capacitive gapping sensor of Fig. 11.

[0035] Fig. 14 is a front view of another embodiment of the capacitive gapping sensor system in a partially assembled form, with only two of three capacitive gapping sensors assembled.

[0036] Fig. 15 is a rear view of the capacitive gapping sensor system of Fig. 14, in which a battery and a controller are visible, without a rear cover assembled.

[0037] Fig. 16 is an oblique front view of another embodiment of the capacitive gapping sensor system.

[0038] Fig. 17 is an oblique front cross-sectional view of the capacitive gapping sensor system of Fig. 16.

[0039] Fig. 18 is another oblique front cross-sectional view of the capacitive gapping sensor system of Fig. 16.

[0040] Fig. 19 is an oblique rear view of the capacitive gapping sensor system of Fig.16.

[0041] Fig. 20 is a side elevation view of the capacitive gapping sensor system of Fig. 16.

[0042] Fig. 21 is an oblique front view of another embodiment of the capacitive gapping sensor system.

[0043] Fig. 22 is an oblique rear view of another embodiment of the capacitive gapping sensor system of Fig. 21.

[0044] Fig. 23 is an oblique rear cross-sectional view of the capacitive gapping sensor system of Fig. 22.

[0045] Fig. 24 is an oblique front view of another embodiment of the capacitive gapping sensor system.

[0046] Fig. 25 is front elevation view of the capacitive gapping sensor of Fig. 24.

[0047] Fig. 26 is an oblique rear view of the capacitive gapping sensor system of Fig. 24.

[0048] Fig. 27 is a side elevation view of the capacitive gapping sensor system of Fig. 24.

[0049] Fig. 28 is an oblique front cross-sectional view of the capacitive gapping sensor system of Fig. 24.

[0050] Fig. 29 is an oblique front view of a front opening unified pod (FOUP) and a robotic arm that is configured to move the capacitive gapping sensor systems into and / or out of the FOUP.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0051] The present disclosure can be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specific devices, methods, applications, conditions or parameters described and / or shown herein, and that the terminology7used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the scope of the present disclosure. Also, as used in the specification including the appended claims, the singular forms “a,” "an." and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0052] The term “plurality”, as used herein, means more than one. When a range of values is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0053] Fig. 1 illustrates one embodiment of a capacitive gapping sensor system 40 that is configured to sense a target object 42 to measure one or more gaps Gi, G2, or G3 between the capacitive gapping sensor system 40 and the target object 42. The measurement may be made without the capacitive gapping sensor system 40 contacting any part of the target object 42.

[0054] The capacitive gapping sensor system 40 may include three capacitance sensors 50a, 50b, and 50c that are each configured to detect the respective gap Gi, G2, or G3. As discussed below, the capacitance sensors 50a, 50b, and 50c may each define a non-circular perimeter, such as an annular sector or a kidney shape. In an embodiment, the capacitivegapping sensor system includes more than three capacitance sensors. In an embodiment, the capacitive gapping sensor system includes one or two capacitance sensors.

[0055] The capacitive gapping sensor system 40 may include a controller 52 that is operably coupled to each of the capacitance sensors 50a, 50b, and 50c. The controller 52 may include a memory 54, a processor 56, a transceiver 58 (e.g.. a wireless transceiver), and / or the like. The transceiver 58 may be configured to communicate with a separate computer system (not shown) that may provide instructions to the controller 52 and may receive measurement data of each of the capacitance sensors 50a, 50b, and 50c from the controller 52.

[0056] The capacitive gapping sensor system 40 may include a power supply (e.g., a battery 60) that is operably coupled to the each of the capacitance sensors 50a, 50b, and 50c (e.g., via the controller 52).

[0057] The capacitive gapping sensor system 40 may include a driver 62 that is operably coupled to the each of the capacitance sensors 50a, 50b, and 50c. The driver 62 may be configured to provide a drive voltage to each of the capacitance sensors 50a, 50b. and 50c. The driver 62 may be configured to provide an independent drive voltage to each of the capacitance sensors 50a, 50b, and 50c, and / or configured to provide the same drive voltage to each of the capacitance sensors 50a, 50b, and 50c. In an embodiment, the capacitance gapping sensor system includes more than one driver (e.g., a separate driver for each capacitance sensor). In an embodiment, the drive voltage is an alternating current (AC) voltage.

[0058] The driver 62 may include a radio frequency (RF) energy source, and a capacitance measurement circuit that is operably coupled to the capacitance sensors 50a, 50b, and 50c (e.g.. via various switches and / or components. Circuitry for measuring capacitance is well known, and may include known analog-to-digital converters as well as suitable excitation and / or driver circuitry.

[0059] Turning to Fig. 2, the capacitance sensor 50a is schematically represented. The capacitance sensor 50a may include similar features as those disclosed for the capacitance sensor of U.S. Patent No. 7,804.306 entitled "Capacitive distance sensing in semiconductor processing tools’’ and granted September 28, 2010, which is hereby incorporated by reference in its entirety. For example, the capacitance sensor 50a may include a probe 64 that is configured to emit an electric field upon the capacitance sensor 50a receiving a drive voltage. The capacitance sensor 50a may include an active shield 68 that is configured to guide the electric field emitted by the probe 64 to the target object. For example, the active shield 68 may be configured to direct the effective electric field along a forward direction Di along a longitudinal axis X toward the target object 42.

[0060] The capacitance sensor 50a may include circuitry 66, such as measurement circuitry, which is operably coupled to the probe 64, as schematically represented with dashed lines.

[0061] Each of the capacitance sensors 50a, 50b, and 50c may be identical to one another. In an embodiment, one or more of the capacitance sensors is not identical to one or more of the others.

[0062] Turning to Fig. 3, the circuitry 66 may include a receiver 80 that is operably coupled to the probe 64 (shown in Fig. 2) and the controller 52 (shown in Fig. 1). For example, the receiver 80 may be configured to communicate sensed capacitance changes to the controller 52.

[0063] The circuitry 66 may include a phase shifter 82 that is configured to phase shift a received drive voltage. For example, the phase shifter 82 may be configured to phase shift a received AC drive voltage (e.g., phase shift by 180°). For example, the circuitry 66 may be configured to selectively direct the drive voltage through the phase shifter 82. In an embodiment, the controller 52 is configured to selectively direct the drive voltage through the phase shifter 82. Phase shifting the drive voltage may provide for reduced sensitivity to stray electric fields and or electrical interferences.

[0064] For example, the capacitance sensor 50a may be driven at a drive voltage that is shifted relative to the drive voltage of one or more adjacent capacitance sensors 50b and 50c. The drive voltage of the capacitance sensor 50a may be provided by an alternating current that is phase shifted 180° relative to another alternating current that provides the drive voltage of the adjacent capacitance sensor 50b and / or the adjacent capacitance sensor 50c. In an embodiment, an alternating current is provided to one capacitance sensor that is different from an alternating current provided to another capacitance sensor, as discussed below.

[0065] The circuitry 66 may include a driver 84 that is configured to provide a drive voltage. The driver 84 may be operably coupled to the probe 64, such that the driver 84 is configured to selectively drive the probe 64 with a drive voltage. For example, the driver 84 may be configured to selectively drive the probe 64 with the drive voltage. The driver 84 may be configured to selectively provide the drive voltage to the phase shifter 82, such that the probe receives a shifted drive voltage (e.g., as discussed above).

[0066] The controller 52 may be configured to operate in a non-uniform mode in which the controller 52 is configured to dnve at least one of the capacitance sensors 50a, 50b, and 50c differently from at least one of the other capacitance sensors 50a, 50b, and 50c. For example, in a first non-uniform mode, the controller 52 may be configured to operate the driver 62 and / or thedriver 84 such that the capacitance sensor 50a is driven at the drive voltage, while none of the adjacent capacitance sensors 50b and 50c are driven. Similarly, the controller 52 may be configured to operate the driver 62 and / or the driver 84 such that the capacitance sensor 50b is driven at the drive voltage, while none of the adjacent capacitance sensors 50a and 50c are driven. Also, the controller 52 may be configured to operate the driver 62 and / or the driver 84 such that the capacitance sensor 50c is driven at the drive voltage, while none of the adjacent capacitance sensors 50a and 50b are driven.

[0067] Driving only one of the capacitance sensors 50a, 50b, and 50c at a time mayincrease the sensitivity of the capacitive gapping sensor system 40 compared to modes that drive several of the capacitive sensors 50a, 50b, and 50c at the same time. In an embodiment, the capacitive gapping sensor system 40 includes n-number of separate capacitance sensors, and only one is operated during a given stage during the first non-uniform mode. In an embodiment, each capacitive sensor has its own driving circuitry, and thus when one capacitance sensor is driven and the controller 52 operates the other capacitance sensors in a high impedance state to isolate disabled drivers from interfering with the measurement of the capacitance sensor that is being driven.

[0068] The controller 52 may be configured to cycle through each of the capacitive sensors 50a, 50b. and 50c to receive measurements from each of the capacitive sensors 50a, 50b. and 50c. The orientation of the target object 42 may be determined based on the measurements from all capacitive sensors 50a, 50b, and 50c that are taken at different times.

[0069] In a second non-uniform mode, the controller 52 may be configured to operate the driver 62 and / or the driver 84 such that the capacitance sensor 50a is driven at the drive voltage that is shifted relative to the drive voltage of one or more adjacent capacitance sensors 50b and 50c.

[0070] Driving different capacitance sensors 50a, 50b, and 50c at a phase shift (e.g., 180°) from one another may provide for reducing external influences, such as noise errors, from measurements. The phase shifted AC drive signals may provide for less sensitivity to some external influences, such as noise errors, thereby reducing some error that may otherwise occur in the gap measurement of the respective capacitance sensors 50a, 50b, and 50c.

[0071] The second non-uniform mode may be referred to as a push-pull mode. For example, as shown in Fig. 4, when the capacitance sensor 50a is pushing a first electric field Fi, the capacitance sensor 50b is pulling a second electric field F2.

[0072] The controller 52 may be configured to drive the first capacitive sensor plate with a first alternating current voltage and drive the second capacitive sensor plate with a secondalternating current voltage, and the controller is configured to swing the first alternating current voltage and the second alternating current voltage relative to a predetermined voltage. For example, the capacitance sensor 50a may be driven with a first alternating current voltage and the capacitance sensor 50b may be driven with a second alternating current voltage.

[0073] Both the first alternating current voltage and the second alternating current voltage may swing relative to a predetermined voltage. For example, the first alternating current voltage and the second alternating current voltage may swing relative to 0 volts (V) such that the first alternating current voltage is at 100% of the max voltage (e.g., 1.0 V) when the second alternating current voltage is at -100% of the max voltage (e.g., -1.0 V). In some embodiments, the first alternating current voltage and the second alternating current voltage may swing relative to 50% of a max voltage (e.g., 0.5 V) such that the first alternating current voltage is at 100% of the max voltage (e.g., 1.0 V) when the second alternating current voltage is at 0% of the max voltage (e.g., 0 V).

[0074] The first and second voltages being out of phase with one another may provide for reduced sensitivity to stray electric fields and interferences, which may provide for sensing a distance to an electrically floating target.

[0075] Referring again to Fig. 3, in a third non-uniform mode, the controller 52 may be configured to respectively operate the driver 62 and / or the driver 84 such that the capacitance sensor 50a is driven simultaneously with the capacitance sensor 50b and at the same drive voltage (e.g., at the same amplitude) as one another, while the capacitance sensor 50c is not driven (e.g., at an amplitude of 0 V).

[0076] In the third non-uniform mode, the controller 52 may be configured to operate in multiple different stages. For example, in a first stage, the controller 52 may be configured to respectively operate the driver 62 and / or the driver 84 such that the capacitance sensor 50a is driven simultaneously with the capacitance sensor 50b and at the same drive voltage as one another, while the capacitance sensor 50c is not driven. In a second stage, the controller 52 may be configured to respectively operate the driver 62 and / or the driver 84 such that the capacitance sensor 50b is driven simultaneously with the capacitance sensor 50c and at the same drive voltage as one another, while the capacitance sensor 50a is not driven. In a third stage, the controller 52 may be configured to respectively operate the driver 62 and / or the driver 84 such that the capacitance sensor 50a is driven simultaneously with the capacitance sensor 50c and at the same drive voltage as one another, while the capacitance sensor 50d is not driven.

[0077] The controller 52 may be configured to transition between stages, which may provide for measuring a gap between the target object 42 and respective sets of the capacitancesensors 50a, 50b. and 50c. Thus, the controller 52 may determine the onentation of the target object 42 (e.g., the incline) relative to the capacitive gapping sensor system 40. For example, the controller 52 may be configured to transition from the first stage to the second stage, from the second stage to the third stage, and / or from the third stage to another stage or the first stage.

[0078] In an embodiment, the controller is configured to selectively operate in any one of the non-uniform operating modes. In another embodiment, the controller is configured to operate in only one of the non-uniform operating modes. In an embodiment, the capacitive gapping sensor system includes only two capacitance sensors, each of which is driven differently from the other. In another embodiment, the capacitive gapping sensor system 40 includes four or more capacitance sensors, where at least two of the capacitance sensors are driven differently from at least one of the others (e.g., in the first non-uniform operating mode, or during each stage of the second non-uniform operating mode).

[0079] The controller 52 may be configured to transition between modes. For example, between any of the first non-uniform mode, the second non-uniform mode, the third non-uniform mode, and / or another mode (e.g., a simultaneous mode discussed below with reference to Figs. 1 and 5).

[0080] With reference to Fig. 1, the controller 52 may be configured to transition to the simultaneous mode. In the simultaneous mode, the controller 52 may be configured to drive each one of the capacitance sensors 50a, 50b, and 50c (e.g., the probes 64, as discussed below) simultaneously at the same amplitude, as discussed below with reference to Fig. 5. Driving multiple of the capacitance sensors 50a, 50b, and 50c simultaneously in the simultaneous mode may provide for increasing an effective sensing surface area beyond that of an individual one of the capacitance sensors 50a, 50b, or 50c. The increased effective surface area may provide for increased measurement sensitivity (e.g., sensing of the target object 42 that is 50 mm away, as opposed to being 15 mm to 25 mm away for a single one of the capacitance sensors 50a, 50b, or 50c).

[0081] Turning to Fig. 5. in the simultaneous mode the controller 52 (shown in Fig. 1) may be configured to operate the driver 84 such that each of the capacitance sensors 50a, 50b, and 50c are driven at the same drive voltage (e.g., at the same amplitude) as one another. For example, each of the probes 64 may be driven at the same drive voltage (e.g., at the same amplitude) as one another. The respective active shield 68 may be driven at a different drive voltage, as discussed below. In an embodiment, the active shield may be driven at the same drive voltage.

[0082] As represented with the ellipses “ . . ” between capacitance sensors 50b and 50c and with capacitance sensor 50c being labeled number “n,” the capacitive gapping sensor system 40 may include “n” number of capacitance sensors. In an embodiment, the capacitive gapping sensor system includes four or more capacitive sensors that are each driven at the same drive voltage (e.g., at the same amplitude) as one another when in the simultaneous mode. In another embodiment, the capacitive gapping sensor system 40 includes two capacitive sensors that are each driven at the same drive voltage (e.g., at the same amplitude) as one another when in the simultaneous mode.

[0083] The controller 52 may be configured to send and / or receive signals to receive information from or direct operation of the capacitance sensors 50a, 50b, and 50c and each of the other components of the capacitive gapping sensor system 40 (e.g., the transceiver 58 and the driver 62). For example, the controller 52 may be configured to receive data (e.g., voltage output) from the capacitance sensors 50a, 50b. and 50c and / or an external electronic device (e.g., wirelessly via a transceiver 58). The controller 52 may be configured to store information received from the capacitance sensors 50a, 50b, and 50c and / or an external electronic device, for example, in the memory' 172.

[0084] The controller 52 may include, or be operatively connected to, one or more of the capacitance sensors 50a, 50b, and 50c, the driver 62, the circuitries 66, the active shields 68, the probes 64, the drivers 84, the phase shifters 82, the receivers 90, and / or an external electronic device.

[0085] The processor 56 may be configured to connect with and communicate with the memory’ 54, which may be configured to receive and store the measured values and / or the operating modes. The memory’ 54 may include a random access memory (RAM) and / or a computer-readable storage medium, such as a read-only memory (ROM) or non-volatile RAM (NVRAM), for storing basic routines for starting and / or operating the processor 56, which maybe configured as a controller, and / or another component of the capacitive gapping sensor system 40 and to transfer information between the various components and devices of the capacitive gapping sensor system 40. The memory 54 may also store other software components necessary for the operation of the processor 56 and / or other components of the capacitive gapping sensor system 40 including an operating system, software implementing a cleaning method as described herein, and / or the like. The processor 56 may include, or may be connected to, or otherwise in communication with, computer-readable storage media to store and retrieve information, such as program modules, data structures, or other data. It should be appreciated by those skilled in the art that computer-readable storage media may be any available media that provides for thestorage of non-transitory data and that may be accessed by the processor 56. By way of nonlimiting example, the computer-readable storage media may include volatile and non-volatile storage media, transitory7computer-readable storage media, non-transitor ' computer-readable storage media, and removable and non-removable media implemented in any method or technology. Computer-readable storage media includes, but is not limited to, RAM, ROM, erasable programmable ROM ('‘EPROM”), electrically erasable programmable ROM (“EEPROM”), flash memory7or other solid-state memory technology, compact disc ROM (“CD- ROM”), digital versatile disk (“ DVD”), hrgh definition DVD (“HD-DVD”), BLU-RAY, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, other magnetic storage devices, or any other medium that may be used to store the desired information in a non- transitory7fashion.

[0086] Turning to Figs. 6-10, the capacitive gapping sensor system 40 is illustrated in an assembled state. The capacitive gapping sensor system 40 may define a wafer shape such that the capacitive gapping sensor system 40. The wafer shape of the capacitive gapping sensor system 40 may provide for placement of the capacitive gapping sensor system 40 in a Front Opening Universal Pod (FOUP) 86 (e.g., as shown in Fig. 29) or semiconductor processing system (not shown) in place of a wafer that would be processed. The FOUP 86 may be, for example, as disclosed in U.S. Patent Publication No. 2008 / 0228430, entitled “Wireless sensor for semiconductor processing systems” and published on August 17, 2010, which is incorporated by reference in its entirety. As shown in Fig. 29, a robotic arm 88 may be configured to move the capacitive gapping sensor system 40 into and / or out of the FOUP 86 while in a clean environment. The robotic arm 88 may be configured to move the capacitive gapping sensor system 40 into the semiconductor processing system (not shown) while in the clean environment, to measure the target object 42 (e g., a showerhead), such as measuring a gapping and / or an orientation.

[0087] Referring again to Figs. 6-10, the wafer shape may define a circle in aZ-Y axis and may be thin along the longitudinal axis X. The longitudinal axis X may be perpendicular to both a first lateral axis Y and a second lateral axis Z (extending into the page of Fig. 6, and shown in Fig. 7). The first lateral axis Y may be perpendicular to the second lateral axis Z.

[0088] The capacitive gapping sensor system 40 may include a housing 100 that defines a front end 100a that is offset from a rear end 100b along the longitudinal axis X. The housing 100 may include a monolithic housing body 102 that defines a circular outer perimeter. For example, the monolithic housing body 102 may define a wafer shape.

[0089] The monolithic housing body 102 may be made of an electrically conductive material. For example, the monolithic housing body 102 may be a single-piece that is entirely made of carbon fiber. The carbon fiber may provide for the housing 100 having a thinner profile compared to wafer shaped gapping sensor systems that are made from other materials, such as aluminum, while reducing weight and maintaining sufficient strength for the housing 100. In conjunction with the stiffening ribs 112a, 112b, 112c, and 1 12d, the fiberglass material may provide for a significant size reduction compared to compared to different wafer shaped gapping sensor systems that have aluminum housings. In an embodiment, a multi-piece housing body is provided in place of the monolithic housing body.

[0090] The housing 100 may include a cover, such as a rear cover 104 (shown in Figs. 8 and 10), that may be configured to be flush with the monolithic housing body 102 to together define a planar end. For example, the rear cover 104 and monolithic housing body 102 may be contiguous such that the rear cover 104 and monolithic housing body 102 together form the rear end 100b, which may be planar.

[0091] Referring to Figs. 6, 7, and 10, the housing 100 may define one or more sensor cavities 110a, 110b, and 110c that are configured to receive a respective one of the capacitance sensors 50a, 50b, or 50c. The sensor cavities 110a, 110b, and 110c may each define non-circular shaped outer perimeter that matches the shape of the outer perimeter of the respective capacitance sensor 50a, 50b, or 50c. For example, each outer perimeter of the sensor cavities 110a, 110b, and 110c may define an annular sector or kidney shape.

[0092] The capacitance sensors 50a, 50b, and 50c may attach to the housing 100. For example, the capacitance sensors 50a, 50b, and 50c may each be attached to the housing 100 with fasteners (not shown) or in another suitable manner. The capacitance sensors 50a, 50b. and 50c may be at least partially conductively coupled to the housing 100 (e.g., electrically coupled to the monolithic housing body 102). For example, electrically conductive fasteners may attach to at least a portion of the capacitance sensors 50a, 50b, and 50c to the monolithic housing body 102.

[0093] The monolithic housing body 102 may define protrusions 130 (e.g., in a similar manner as show n in Fig. 14) that may be configured to abut a rear surface of a respective one of the capacitance sensors 50a, 50b, or 50c. For example, the protrusions 130 may include an electrically conductive material (e.g., carbon fiber or a metal insert) that are configured to electrically couple a portion of the respective one of the capacitance sensors 50a, 50b, or 50c to the monolithic housing body 102 and / or another component (e.g., to the controller 52, the driver 62, and / or another electronic component).

[0094] The capacitance sensors 50a. 50b, and 50c may be disposed at least partially within a respective one of the sensor cavities 110a, 110b, and 110c and attached to a portion of the housing 100 that defines the respective sensor cavity 110a, 110b, or 110c. As discussed above, each of the capacitance sensors 50a, 50b, or 50c may define a non-circular outer perimeter, such as an annular sector or kidney shape. For example, each of the capacitance sensors 50a, 50b, or 50c may each include a plate shaped body that defines the respective noncircular outer perimeter, as discussed further below. Thus, the shape of the outer perimeter of the capacitance sensors 50a, 50b, or 50c may complement or match the shape of the inner perimeter defined by the respective sensor cavity 110a, 110b, or 110c.

[0095] The non-circular shaping of the capacitance sensors 50a, 50b, or 50c may provide for increased surface sensing area compared to a circular sensor. For example, the capacitance sensors 50a, 50b, or 50c may be coplanar. Also, the housing 100 may define a circular or wafer shaped outer perimeter. Thus, arranging the capacitance sensors 50a, 50b, or 50c within the housing 100 may provide for a larger effective sensing area compared to circular shaped sensors that are arranged within a circular or wafer shaped housing.

[0096] The monolithic housing body 102 may form one or more stiffening ribs 112a, 112b, 112c, and 112d. Each of the stiffening ribs 112a, 112b, 112c, and 112d may extend along a Z-Y plane and be non-parallel with one another.

[0097] Each sensor cavity 110a, 110b, and 110c may be at least partially defined by respective stiffening ribs 112a, 112b, 112c, and 112d. For example, the sensor cavity’ 110a may be circumscribed by the stiffening ribs 112a, 112b, and 112d. The sensor cavity 110b may be circumscribed by the stiffening ribs 112b, 112c, and 112d. The sensor cavity 110c may be circumscribed by the stiffening ribs 112a, 112c, and 112d.

[0098] The stiffening ribs 112a, 112b, and 112c may extend radially. For example, a radially inner end of each of the stiffening ribs 112a, 112b, and 112c may converge together at a central portion of the monolithic housing body 102. The radially inner ends of the stiffening ribs 112a. 112b, and 112c may together define a circular portion.

[0099] The stiffening ribs 112a, 112b, and 112c may each extend along a respective angularly offset axis Ri, R2, or R3 (identified in Fig. 7) that extends along the Z-Y plane. Each angularly offset axis Ri, R2, or R3 may be angularly offset from one another by an acute angle. For example, the acute angle may be the acute angle may be 60° and each angularly offset axis Ri, R2, and R3 may extend to a common point at a central portion of the monolithic housing body 102. In an embodiment, the acute angle may be anywhere from 15° to 75°, 25° to 70°, 35° to 70°, 45° to 65°, or 55° to 65°.

[0100] The stiffening rib 112d may extend annularly. For example, the stiffening rib 112d may converge with a radially outer end of each of the stiffening ribs 112a, 112b, and 112c.

[0101] In an embodiment, the monolithic housing body may implement three or less stiffening ribs that each extend along the Z-Y plane. In another embodiment, the housing bodyforms more than four stiffening ribs that each extend along the Z-Y plane.

[0102] Each sensor cavity 110a, 110b, and 1 10c may be identically shaped and sized. For example, each sensor cavity 110a, 110b, and 110c may be identical and arranged circumferentially spaced from each adjacent sensor cavity 110a, 110b, or 110c. Each sensor cavity 110a, 110b, and 110c may be circumferentially equidistant from one another along the Z- Y axis.

[0103] Referring to Figs. 8 and 10, each of the stiffening ribs 112a, 112b, 112c, and 112d may define a respective rear cavity 120a, 120c, 120c, or 120d that faces along a rearw ard direction away from the forward direction Di. For example, each of the rear cavities 120a, 120b, and 120c may extend along the respective stiffening rib 112a. 112b. or 112c (and / or the respective angularly offset axis Ri, R2, or R3) along the Z-Y plane. The radially inner ends of the rear cavities 120a, 120b, and 120c may converge to together to define a circular cavity portion.

[0104] The controller 52, the battery 60, the driver 62, and / or another electronic component may be disposed within the rear cavities 120a. 120b, 120c, and 120d. For example, the controller 52 may be disposed in the rear cavity 120c and disposed in the circular cavity portion defined by the rear cavities 120a, 120b, and 120c (e.g., in a similar manner as shown in Fig. 15). The battery 60 may be disposed in the rear cavity- 120c (e.g., in a similar manner as shown in Fig. 15). The driver 62 may be disposed in the rear cavity 120b (e.g., in a similar manner as shown in Fig. 15). In an embodiment, the controller 52, the battery 60, the driver 62, and / or the another electronic component is disposed in a different one of the rear cavities. In an embodiment, the controller 52, the battery- 60, the driver 62, and / or the another electronic component are electrically coupled to the capacitive sensors and / or the housing via electrical wiring or other electrical conduits that extend within or through the housing. For example, electrical wiring may extend through holes in the stiffening ribs or another part of the housing.

[0105] The annular rear cavity 120d may converge with a radially outer end of each of the rear cavities 120a, 120b, and 120c.

[0106] The rear cover 104 may be configured to be disposed within the rear cavities 120a, 120b, 120c, and 120d. For example, the rear cover 104 may be configured to attach to the monolithic housing body' 102 such that the rear cover 104 and the monolithic housing body 102together define the rear end 100b. The rear cover 104 may be attached to the monolithic housing body 102 with fasteners (not shown) or in another suitable manner.

[0107] Referring to Fig. 9, the monolithic housing body 102 may have a major surface that extends along the Z-Y plane, and an extent of the entire monolithic housing body 102 along the longitudinal axis X that is perpendicular to the Z-Y plane may be a thickness T of 3.5 millimeters (mm). In an embodiment, the thickness T is anywhere from 1 millimeter (mm) to 10 mm, 2 mm to 10 mm, 2 mm to 9 mm, 2 mm to 8 mm, 2 mm to 7 mm, 2 mm to 6 mm, 2 mm to 5 mm, 2 mm to 4.5 mm, 2 mm to 4 mm, or 3 mm to 4 mm.

[0108] For example, the extent of the entire monolithic housing body 102 along the longitudinal axis X may be equal to or less than 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, or 4 mm, and / or may be equal to or greater than 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 7.5 mm.

[0109] An outermost diameter OD of the monolithic housing body 102 may be 200 mm, 300 mm, or 450 mm. In an embodiment, the outermost diameter OD is anywhere from 50 mm to 500 mm, 100 mm to 400 mm, 150 mm to 450 mm, 150 mm to 350 mm, or 200 mm to 300 mm.

[0110] A single plane (e.g.. that is parallel to the Z-Y plane) may extend through each sensor cavity 110a. 110b, and 110c and each rear cavity 120a. 120b, 120c, and 120d. For example, the sensor cavities 110a, 110b, and 1 10c and the rear cavities 120a, 120b, 120c, and 120d may overlap along a circumferential direction that the sensor cavities 110a, 110b, and 110c and the rear cavities 120a, 120b, 120c, and 120d are spaced apart along.[OHl] Briefly referring to Fig. 10, the cross-sectional thickness of the monolithic housing body 102 may be constant. Thus, each portion of the monolithic housing body 102 may be formed by a material of constant thickness, which may provide for a compact profile that reduces waste and a total package thickness.

[0112] Turning to Figs. 12 and 13, the capacitance sensor 50a (also shown in Fig. 11) may include a capacitive sensor plate 140 (also referred to as a sensing pad, which may be a part of the probe 64 of Fig. 2). The capacitive sensor plate 140 may be formed of an electrically conductive material, such as a metal (e.g., gold).

[0113] The capacitive sensor plate 140 may define an annular sector shape. In an embodiment, the capacitive sensor plate may form a kidney shape or another non-circular shape.

[0114] The capacitance sensor 50a may include a grounding plate 142 (e.g., of the probe 64 of Fig. 2) that defines an outer periphery that has a similar shape as the capacitive sensor plate 140. For example, the outer periphery of the grounding plate 142 may have anannular sector shape. The grounding plate 142 may define an inner periphery that also defines an annular sector shape that the capacitive sensor plate 140 is disposed within.

[0115] The capacitance sensor 50a may include an electrically insulative material 146 between the inner periphery of the grounding plate 142 and the outer periphery of the capacitive sensor plate 140. For example, the electrically insulative material 146 may circumscribe the outer periphery of the capacitive sensor plate 140 to electrically separate the grounding plate 142 from the capacitive sensor plate 140. The electrically insulative material 146 may define a shape (e.g., an annular sector) that fills a space that is between the capacitive sensor plate 140 and the grounding plate 142.

[0116] The active shield 68 may include an active shield member 144 that defines an outer periphery that has a similar shape as the capacitive sensor plate 140. For example, the outer periphery' of the active shield member 144 may have an annular sector shape. The active shield member 144 may define an inner periphery that also defines an annular sector shape that the grounding plate 142 (and the capacitive sensor plate 140) is disposed within.

[0117] The capacitance sensor 50a may include an electrically insulative material 148 between the inner periphery of the active shield member 144 and the outer periphery of the grounding plate 142. For example, the electrically insulative material 148 may circumscribe the outer periphery of the grounding plate 142 to electrically separate the active shield member 144 from the grounding plate 142. The electrically insulative material 148 may define a shape (e.g., an annular sector) that fills a space that is between the grounding plate 142 and the active shield member 144.

[0118] Referring to Figs. 1, 2, and 13, the active shield 68 may include active shield circuitry 150 that is disposed on a read end of the active shield member 144. The active shield circuitry 150 may be configured to electrically couple with the controller 52, the driver 62, and / or the circuitry' 66. For example, the controller 52 may be configured to operate the active shield member via the driver 62, the circuitry' 66, and / or the active shield circuitry' 150.

[0119] The outer perimeter of the active shield member 144 in the Z-Y plane may be concentric with the inner perimeter of the sensor cavity 110a in the Z-Y plane. For example, the outer perimeter of the active shield member 144 may be complementarily shaped with the noncircular inner perimeter defined by the respective sensor cavity' 110a in the Z-Y plane (or a parallel plane). The interior perimeter of the active shield member 144 may be complementarily shaped with the non-circular outer perimeter of the grounding plate 142 in the Z-Y plane (or a parallel plane).

[0120] As discussed above, each of the capacitance sensors 50a. 50b, and 50c may be identical to one another.

[0121] The monolithic housing body 102 may be configured to shield the active shield circuitry' 150 circuitry' and / or the circuitry 66 from electrical interference (e g., a stray electric field) from the controller 52. the battery, and / or the driver 62. For example, the active shield circuitry 150 circuitry and / or the circuitry 66 may be provided inside a respective one of the sensor cavities 110a, 110b, or 110c (e.g., between the monolithic housing body 102 and a rear side of the capacitive sensor plate 140, the grounding plate 142, and the active shield member). This configuration may provide for a reduced trace length of the drive circuitry, yvhich may minimize electrical interferences, thereby increasing measurement stability. Also, the controller 52 may include voltage conditioning circuitry.

[0122] In an embodiment, the monolithic housing body 102 is configured to shield analog circuitry components that are disposed on the front of the monolithic housing body 102 from digital components (e.g., of the controller) that are disposed on the rear of the monolithic housing body 102 (see e.g.. Figs. 14 and 15). In an embodiment, the monolithic housing body 102 is configured to shield analog circuitry' components that are disposed on the front of the monolithic housing body 102 from digital components (e.g., of the controller) that are also disposed on the front of the monolithic housing body 102 (see e.g., Figs. 17 and 18).

[0123] The controller 52 may be configured to drive each active shield member 144 and respective capacitive sensor plate 140 at different amplitudes from one another. For example, the controller 52 may be configured to drive one or more of the probes 64 (e.g., by driving the respective capacitive sensor plate 142) at a first amplitude, and the controller 52 may be configured to drive one or more of the active shield members 144 at a second amplitude that is different from the first amplitude. For example, the active shield members 144 can be driven anywhere from 0 V to the active shield’s maximum amplitude (e.g., adjusting the drive in a stepless manner). Adjusting of the drive of the shield members 144 may provide for adapting to external conditions to improve a sensitivity curve for the particular target object 42.

[0124] The controller 52 may be configured to adjust the second amplitude relative to the first amplitude and / or adjust the first amplitude relative to the second amplitude. Adjusting the second amplitude, for example, may provide for tuning of the active shield member 144. Thus, controller 52 may tune the active shield member 144 depending on the first amplitude and / or a desired sensitivity of the probe 64. The first amplitude and / or the second amplitude may thus be adjusted to provide for maximizing of the respective probe 64.

[0125] For example, the controller 52 may be configured to tune each active shield member 144 by adjusting the second amplitude such that the respective probe 64 has a sensitivity above a predetermined threshold.

[0126] Referring also to Fig. 6, the active shield member 144 may be electrically coupled to the monolithic housing body 102 such that the active shield member 144 and the monolithic body 102 together form the active shield 68 of Fig. 2. For example, the controller 52 may be configured to drive the active shield member 144 via the monolithic housing body 102 such that the monolithic housing body 102 and the active shield member 144 may direct the electric fields emitted by each respective probe 64 to the target object 42. The stiffening ribs 112a, 112b, 1 12c, and 112d may form a portion of the active shield 68 (e.g., comprising another active shield member) that may be driven along with the active shield members 144 to direct the electric fields emitted by the probes 64 to the target object 42.

[0127] The controller 52 is configured to drive each respective active shield member 144 independently of the other active shield members 144. For example, each active shield member 144 may be driven based on the driving amplitude of the respective probe 64 and / or a desired sensitivity for the respective probe 64.

[0128] During use, each probe 64 may be driven at a respective first amplitude to emit a respective first electric field toward the target object 42. For example, the controller 52 may drive each capacitive sensor plate 140 based on the mode of operation as discussed above.

[0129] Each probe 64 may sense a capacitance between the respective capacitive sensor plate 140 and the target object 42. Thus, based on the sensed capacitance, the controller 52 may determine a respective gap Gi, G2, or G3 between the respective capacitive sensor plate 140 and the target object 42 based on the respective sensed capacitance. In an embodiment, an external device determines the respective gap Gi, G?, or G3 based on the sensed capacitance.

[0130] The transceiver 58 may wirelessly transmit sensing data that is based on each sensed capacitance to an external device (not shown). For example, the controller 52 may operate the transceiver 58 to wirelessly transmit the sensed data, including sensed capacitances and / or the gaps gap Gi, G2, or Gy to the external device. In an embodiment, the transmission is not wireless.

[0131] Referring now to Figs. 14 and 15. a second embodiment of the capacitive gapping sensor system is shown. It is to be appreciated that the second embodiment can be similar to the first embodiment of the capacitive gapping sensor system 40 shown in Figs. 1-13. Accordingly, the same reference numbers used above with reference to the first embodiment can be also used with a "prime" notation in reference to the second embodiment. It is also to beappreciated that, unless otherwise set forth below, the components (and features thereof) of the capacitive gapping sensor system 40’ of the second embodiment can be similar to those of the first embodiment.

[0132] The capacitive gapping sensor system 40’ (shown with one capacitance sensor and a rear cover removed) may include a monolithic housing body 102’. The monolithic housing body 102’ may include the sensor cavities 110a, 1 10b, and 110c and rear cavities 120a’, 120c’, and 120c’. The capacitive gapping sensor system 40’ may include an electrical connector 160 that is configured to electrically couple the controller 52, the battery' 60, the driver 62 and / or another electronic to the capacitance sensors 50a, 50b. and 50c (capacitance sensor 50c is represented in Fig. 6) and / or the monolithic housing body 102’.

[0133] The radially outer portions of the rear cavities 120a’, 120c’, and 120c’ may define a respective arcuate portion 162a, 162b, or 162c that does not extend to any of the adjacent arcuate portions 162a, 162b, or 162c.

[0134] Referring now to Figs. 16-20. a third embodiment of the housing is shown. It is to be appreciated that the third embodiment can be similar to the first embodiment of the housing show n in Figs. 6-10 and the second embodiment of the housing show n in Figs. 14 and 15. Accordingly, the same reference numbers used above with reference to the first embodiment or the second embodiment can be also used with a “double prime” notation in reference to the third embodiment. It is also to be appreciated that, unless otherwise set forth below, the components (and features thereof) of the housing 100” of the third embodiment can be similar to those of the first embodiment and / or the second embodiment. Moreover, unless otherwise set forth below', the capacitive gapping sensor system of the first embodiment or the second embodiment may include the housing 100” instead of the other housings discussed above. For example, corresponding components, such as the capacitance sensors, the controller, the battery, the driver, and / or another electronic component, may be disposed in respective cavities of the housing 100”. Moreover, capacitance sensors may define a shape that is complementary with a respective sensor cavity of the housing, such that each capacitance sensor may be similarly disposed in the respective sensor cavity.

[0135] The housing 100” may define a first end 100a” and a second end 100b”. The housing 100” may include a monolithic housing body 102’ that defines a circular outer perimeter. For example, the monolithic housing body 102’ may define a wafer shape.

[0136] The monolithic housing body 102’ may form one or more stiffening ribs 112a”, 112b”, 112c”, 112d”, and 200. For example, the stiffening ribs 112a”, 112b”, and 112c” may extend radially from the stiffening rib 200, which may define an annular shape that is coaxialwith an outer perimeter of the monolithic housing body. The stiffening ribs 112a”, 112b”, and 112c” may extend radially to the stiffening rib 112d”, which may define an annular shape that is coaxial with the stiffening rib 200 and the outer perimeter of the monolithic housing body.

[0137] Referring to Figs. 17 and 18, the stiffening ribs 112a” may be parallel to one another and circumferentially spaced apart such that a front cavity’ 120a” that faces along a forward direction Di is defined. The stiffening ribs 112b” may be parallel to one another and circumferentially spaced apart such that a front cavity 120b” that faces along the forward direction Di is defined. The stiffening ribs 112c” may be parallel to one another and circumferentially spaced apart such that a front cavity 120c” that faces along the forward direction Di is defined. The stiffening rib 200 may define a front cavity 200a that defines an annular shape.

[0138] Thus, the controller 52, the battery’ 60, the driver 62, and / or another electronic component discussed with reference to Figs. 14 and 15, for example, may be disposed within the front cavities 120a”. 120b”. 120c”. and / or 200a in a similar manner as shown in Figs. 14 and 15.

[0139] Referring to Figs. 16 and 17, the housing 100” may include a front cover 104”. The front cover 104” may be configured to be disposed within the front cavities front cavities 120a”, 120b”, 120c”, and / or 200a. For example, the front cover 104” may be configured to attach to the monolithic housing body 102” such that the front cover 104” and the monolithic housing body 102” together define the front end 100b”. The front cover 104” may be attached to the monolithic housing body 102b” with fasteners (not shown) or in another suitable manner.

[0140] Referring to Figs. 19 and 20, the rear end 100b” may define a rear planar surface. For example, the monolithic housing body 102” may define the entire rear planar surface.

[0141] Referring now to Figs. 21-23, a fourth embodiment of the housing is shown. It is to be appreciated that the fourth embodiment can be similar to the first, second, or third embodiments of the housing discussed above. Accordingly, the same reference numbers used above with reference to the first embodiment, the second embodiment, or the third embodiment can be also used with a “triple prime” notation in reference to the fourth embodiment. It is also to be appreciated that, unless otherwise set forth below, the components (and features thereof) of the housing 100”’ of the fourth embodiment can be similar to those of the first embodiment, the second embodiment, and / or the third embodiment. Moreover, unless otherwise set forth below, the capacitive gapping sensor system of the first embodiment or the second embodiment may include the housing 100”’ instead of the other housings (or monolithic housing bodies)discussed above. For example, corresponding components, such as the capacitance sensors, the controller, the battery, the driver, and / or another electronic component, may be disposed in respective cavities of the housing 100”’. Moreover, capacitance sensors may define a shape that is complementary with a respective sensor cavity of the housing, such that each capacitance sensor may be similarly disposed in the respective sensor cavity.

[0142] The housing 100’” may include a monolithic housing body 102”’. In this embodiment, the rear cover 104 may not be included or the monolithic housing body 102’” may replace any of the monolithic housing bodies discussed above.

[0143] The monolithic housing body 102’” may form one or more stiffening ribs 112a”’, 112b’”, 112c”’, and 112d’”. The monolithic housing body 102’” may define one or more sensor cavities 110a’”, 110b’”, and 110c’” that are configured to receive a respective one of the capacitance sensors 50a, 50b, or 50c (shown in Fig. 6). Each of the stiffening ribs 112a”’, 112b”', 112c’”, and 112d” ' may define a respective rear cavity 120a’”, 120c'”, 120c”’, or 120d’”.

[0144] None of the sensor cavities 1 10a”’, 110b’”, and 1 10c”’ or the rear cavities 120a”’, 120c’”, 120c’”, and 120d’” include a protrusion for supporting a respective capacitance sensor or other component.

[0145] Referring now to Figs. 24-28. a fifth embodiment of the housing is shown. It is to be appreciated that the fifth embodiment can be similar to the first, second, third, or fourth embodiments of the housing discussed above. Accordingly, the same reference numbers used above with reference to the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment can be also used with a ‘"quadruple prime” notation in reference to the fifth embodiment. It is also to be appreciated that, unless otherwise set forth below, the components (and features thereof) of the housing 100”” of the fifth embodiment can be similar to those of the first embodiment, the second embodiment, the third embodiment, and / or the fourth embodiment. Moreover, unless otherwise set forth below; the capacitive gapping sensor system of the first embodiment or the second embodiment may include the housing 100”” instead of the other housings (or monolithic housing bodies) discussed above. For example, corresponding components, such as the capacitance sensors, the controller, the battery, the driver, and / or another electronic component, may be disposed in respective cavities of the housing 100””. Moreover, capacitance sensors may define a shape that is complementary with a respective sensor cavity of the housing, such that each capacitance sensor may be similarly disposed in the respective sensor cavity.

[0146] The housing 100’ ’ ” may include a monolithic housing body 102””. In this embodiment, the rear cover 104 may not be included.

[0147] The monolithic housing body 102”” may define a stiffening portion 112””. The monolithic housing body 102”” may define one or more sensor cavities 110a””, 110b””, and 110c”” that are configured to receive a respective one of the capacitance sensors 50a, 50b, or 50c (shown in Fig. 6). For example, the sensor cavities 110a””, 1 10b””, and 1 10c”” may be formed in the stiffening portion 112””.

[0148] The sensor cavities 110a””, 110b””, and 110c”” may be kidney shaped. For example, the sensor cavities 110a””, 110b””, and 110c”” may be each be configured to receive kidney shaped capacitance sensors (not shown). In an embodiment, the sensor cavities are shaped differently from one another to receive differently shaped capacitance sensors.

[0149] The stiffening portion 112”” may be circular except for the sensor cavities 110a””, 110b””, and 110c””. Also, the monolithic housing body 102”” may define a rear cavity 120”” behind the stiffening portion 112””. The rear cavity 120”” may be circular except for kidney shaped portions that define the sensor cavities 1 10a””, 1 10b””, and 1 10c””.

[0150] The following are a number of nonlimiting EXAMPLES of aspects of the disclosure.

[0151] In one general aspect, a non-contact capacitive gapping sensor system may include a housing that includes a monolithic housing body that defines a front end and a rear end that is offset from the front end. The non-contact capacitive gapping sensor system may also include a capacitance sensor that comprises a capacitive sensor plate that is configured to emit a first electric field, where the monolithic housing body defines a sensor cavity at the front end, and where the capacitance sensor is disposed within the sensor cavity such that the capacitance sensor is directed along a forward direction away from the front end and the rear end. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0152] Implementations may include one or more of the following features. The noncontact capacitive gapping sensor system where the sensor cavity is at least partially defined by one or more stiffening ribs. The non-contact capacitive gapping sensor system where the one or more stiffening ribs include at least two stiffening ribs that each extend along a first plane and are non-parallel with one another. The non-contact capacitive gapping sensor system where the at least two stiffening ribs each extend along a respective one of at least two angularly offset axis that extend along the first plane and are angularly offset from one another by an acute angle.The non-contact capacitive gapping sensor system where the sensor cavity is a first sensor cavity, and where the at least two stiffening ribs includes three stiffening ribs that extend axially and together define a portion of the first sensor cavity, a second sensor cavity, and a third sensor cavity, each facing along the forward direction. The non-contact capacitive gapping sensor system where the first sensor cavity, the second sensor cavity, and the third sensor cavity are each identical shaped and sized, and where the first sensor cavity, the second sensor cavity, and the third sensor cavity are each circumferentially spaced from one another by a respective one of the three stiffening ribs. The non-contact capacitive gapping sensor system where the at least two stiffening ribs includes an annularly extending stiffening rib that converges with a radially outer end of each of the three stiffening ribs. The non-contact capacitive gapping sensor system, where each of the one or more stiffening ribs define a rear cavity that faces along a rearward direction opposite the forward direction. The non-contact capacitive gapping sensor system further including a battery, a controller, and / or electronic device disposed within the rear cavity. The non-contact capacitive gapping sensor system, further including at least two additional stiffening ribs that are each parallel to and circumferentially offset from a respective one of the at least two stiffening ribs. The non-contact capacitive gapping sensor system may include a first circuitry that is mounted underneath the capacitive sensor plate. The non-contact capacitive gapping sensor system, where the monolithic housing body defines a rear facing cavity. The non-contact capacitive gapping sensor system, where the capacitance sensor defines a noncircular outer perimeter. The non-contact capacitive gapping sensor system where the noncircular outer perimeter, in a first plane, is concentric with a non-circular inner perimeter defined by the sensor cavity in the first plane. The non-contact capacitive gapping sensor system where the non-circular outer perimeter and the non-circular inner perimeter each define an annular sector shape or each define a kidney bean shape. The non-contact capacitive gapping sensor system, where the capacitance sensor includes an active shield member that is disposed within the sensor cavity and defines an interior space that the capacitance sensor plate is disposed within. The non-contact capacitive gapping sensor system, where the monolithic housing body defines a circular outer perimeter. The non-contact capacitive gapping sensor system, where the monolithic housing body defines a major surface that extends along a first plane, and an extent of an entirety of the monolithic housing body along an axis that is perpendicular to the first plane is anywhere from 1 millimeter (mm) to 10 mm, 2 mm to 10 mm, 2 mm to 9 mm, 2 mm to 8 mm, 2 mm to 7 mm, 2 mm to 6 mm, 2 mm to 5 mm, 2 mm to 4.5 mm, 2 mm to 4 mm, or 3 mm to 4 mm. The non-contact capacitive gapping sensor system, further including a cover coupled to the rear end of the monolithic housing body, where the cover defines a planar surface that forms aplanar rear end of the capacitive gapping sensor system. The non-contact capacitive gapping sensor system, where the monolithic housing body is configured to shield circuitry of the capacitance sensor from a controller of the capacitive gapping sensor system. The non-contact capacitive gapping sensor system, may include at least one active shield member that is configured to emit a second electric field such that the first electric field is directed toward a target object upon the at least one active shield member being driven, where the at least one active shield member defines a space that the capacitive sensor plate is disposed within; where the controller is configured to drive the capacitive sensor plate at a first amplitude, where the controller is configured to drive the at least one active shield member at a second amplitude, and where the controller is configured to adjust the second amplitude relative to the first amplitude. The non-contact capacitive gapping sensor system, where the capacitive sensor plate is a first capacitive sensor plate, and where the non-contact capacitive gapping sensor system further comprises: a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven; and a controller that in a first mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously and / or in a second mode is configured to drive the first capacitive sensor plate differently from the second capacitive sensor plate. Method, having: driving first capacitive sensor plate at the first amplitude to emit the first electric field toward a target object; sensing a first capacitance between the first capacitive sensor plate and the target object; and determining a gap between the first capacitive sensor plate and the target obj ect based on the first capacitance. Method may include: wirelessly transmitting sensing data, that is based on the sensed first capacitance, to an external device. Implementations of the described techniques may include hardware, a method or process, or a computer tangible medium.

[0153] In one general aspect, non-contact capacitive gapping sensor system may include a housing. The non-contact capacitive gapping sensor system may also include a capacitance sensor that comprises: a capacitive sensor plate configured to emit a first electric field upon being driven at a first amplitude; and an active shield member that is configured to emit a second electric field such that first electric field is directed toward a target object upon the active shield member being driven at a second amplitude, where the active shield member defines a space that the capacitive sensor plate is disposed within. System may furthermore include a controller that is configured to drive the active shield member and the capacitive sensor plate, where the controller is configured to drive the active shield member at the second amplitude and is configured to drive the capacitive sensor plate at the first amplitude, and where the controller is configured to adjust the second amplitude relative to the first amplitude. Otherembodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0154] Implementations may include one or more of the following features. The noncontact capacitive gapping sensor system where the second amplitude is different from the first amplitude. The non-contact capacitive gapping sensor system where the housing is wafershaped such that the capacitive gapping sensor system is wafer-shaped. The non-contact capacitive gapping sensor system, where the controller is configured to tune the active shield member by adjusting the second amplitude such that the capacitance sensor has a sensitivity above a predetermined threshold. The non-contact capacitive gapping sensor system, where the controller is configured to drive the active shield member based on the first amplitude and / or a predetermined desired sensitivity level of the capacitance sensor. The non-contact capacitive gapping sensor system, where the active shield member comprises defines a non-circular inner perimeter in a plane that is parallel and offset from a major surface of the capacitive sensor plate. The non-contact capacitive gapping sensor system, where the capacitive sensor plate forms a sensing pad. The non-contact capacitive gapping sensor system, where the housing is electrically coupled to the active shield member such that the housing and the active shield member form an active shield that directs the first electric field to the target. The non-contact capacitive gapping sensor system, where the capacitance sensor is a first capacitive sensor, and where the capacitive gapping sensor further includes a second capacitive sensor and / or a third capacitive sensor. The non-contact capacitive gapping sensor system, where the housing is formed by a monolithic body. The non-contact capacitive gapping sensor system, where the capacitive gapping sensor comprises a wireless transceiver. The non-contact capacitive gapping sensor system, where the capacitive gapping sensor comprises a controller. Implementations of the described techniques may include hardware, a method or process, or a computer tangible medium.

[0155] In one general aspect, non-contact capacitive gapping sensor system may include a housing. The non-contact capacitive gapping sensor system may also include a first capacitance sensor that comprises: a first capacitive sensor plate configured to emit a first electric field upon being driven. System may furthermore include a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven. System may in addition include a controller that in a first mode is configured to drive the first capacitive sensor plate differently from the second capacitive sensor plate. Other embodiments of this aspect include corresponding computer systems, apparatus, and computerprograms recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0156] Implementations may include one or more of the following features. The noncontact capacitive gapping sensor system where the housing is wafer-shaped such that the capacitive gapping sensor system is wafer-shaped. The non-contact capacitive gapping sensor system where the capacitive sensor plate defines a non-circular outer perimeter. The non-contact capacitive gapping sensor system may include a first circuitry that is mounted underneath the first capacitive sensor plate, and a second circuitry that is mounted underneath the second capacitive sensor plate. The non-contact capacitive gapping sensor system, where in the first mode the controller is configured to drive the first capacitive sensor plate with a first electric current, while the second capacitive sensor plate is not driven. The non-contact capacitive gapping sensor system may include a third capacitance sensor that comprises a third capacitive sensor plate that is configured to emit a third electric field upon being driven, where in the first mode the controller is configured to drive only one of the first capacitive sensor plate, the capacitive sensor plate, or the third capacitive sensor plate at a time at a first amplitude, and drive the others of the first capacitive sensor plate, the capacitive sensor plate, or the third capacitive sensor plate at 0 volts. The non-contact capacitive gapping sensor system, where in the first mode the controller is configured to drive the first capacitive sensor plate with a first electric current that is out of phase with a second electric current that drives the second capacitive sensor plate. The non-contact capacitive gapping sensor system, where in the first mode the controller is configured to drive the first capacitive sensor plate with a first alternating cunent voltage and drive the second capacitive sensor plate with a second alternating current voltage, where the controller is configured to swing the first alternating current voltage and the second alternating current voltage relative to a predetermined voltage. The non-contact capacitive gapping sensor system, where in a second mode the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously at a first amplitude. The non-contact capacitive gapping sensor system, may include a third capacitance sensor that comprises a third capacitive sensor plate that is configured to emit a third electric field upon being driven, where in the first mode the controller is configured to drive the first capacitive sensor plate and the third capacitive sensor plate simultaneously at a first amplitude, and drive the second capacitive sensor plate at a second amplitude that is different from the first amplitude. The non-contact capacitive gapping sensor system where in the first mode, the second amplitude is 0 volts. The non-contact capacitive gapping sensor system where in the first mode the controller is configured transition from a first stage, where the controller is configuredto simultaneously driving the first capacitive sensor plate and the third capacitive sensor plate at the first amplitude, to a second stage where the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate at a third amplitude, and drive the third capacitive sensor plate at a fourth amplitude that is different from the third amplitude. The non-contact capacitive gapping sensor system where the third amplitude is equal to the first amplitude, and the fourth amplitude is equal to the second amplitude. The non-contact capacitive gapping sensor system where in the first mode the controller is configured transition from the second stage to a third stage where the controller is configured to drive the second capacitive sensor plate and the third capacitive sensor plate at a fifth amplitude, and drive the first capacitive sensor plate at a sixth amplitude that is different from the fifth amplitude. The non-contact capacitive gapping sensor system where the fifth amplitude is equal to the first amplitude, and the sixth amplitude is equal to the second amplitude. The non-contact capacitive gapping sensor system may include at least one additional capacitance sensor that is configured to emit at least a third electric field upon being driven. The non-contact capacitive gapping sensor system, may include at least one active shield member that is configured to emit a third electric field such that the first electric field and / or the second electric field is directed toward a target object upon the at least one active shield member being driven, where the at least one active shield member defines a space that at least one of the first capacitive sensor plate and the second capacitive is disposed within; where the controller is configured to drive the first capacitive sensor plate at a first amplitude, where the controller is configured to drive the second capacitive sensor plate at a second amplitude, where the controller is configured to drive the at least one active shield member at a third amplitude, and where the controller is configured to adjust the third amplitude relative to the first amplitude and the second amplitude. Implementations of the described techniques may include hardware, a method or process, or a computer tangible medium.

[0157] In one general aspect, non-contact capacitive gapping sensor system may include a housing. The non-contact capacitive gapping sensor system may also include a first capacitance sensor that comprises: a first capacitive sensor plate configured to emit a first electric field upon being driven. System may furthermore include a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven. System may in addition include a controller that in a first mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously. Other embodiments of this aspect include corresponding computer systems, apparatus, andcomputer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0158] Implementations may include one or more of the following features. The noncontact capacitive gapping sensor system where the housing is wafer-shaped such that the capacitive gapping sensor system is wafer-shaped. The non-contact capacitive gapping sensor system where the capacitive sensor plate defines a non-circular outer perimeter. The non-contact capacitive gapping sensor system may include a first circuitry that is mounted underneath the first capacitive sensor plate, and a second circuitry that is mounted underneath the second capacitive sensor plate. The non-contact capacitive gapping sensor system, where the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously at a first amplitude. The non-contact capacitive gapping sensor system, where the controller in a second mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate, where the first capacitive sensor plate is driven with a first electric current that is out of phase with a second electric current that drives the second capacitive sensor plate. The non-contact capacitive gapping sensor system may include at least one additional capacitance sensor that is configured to emit a third electric field upon being driven. The non-contact capacitive gapping sensor system where the controller is configured to drive each of the first capacitance sensor, the second capacitance sensor, and the additional capacitance sensor with the same driver at the same amplitude. The non-contact capacitive gapping sensor system, may include at least one active shield member that is configured to emit a third electric field such that the first electric field and / or the second electric field is directed toward a target object upon the at least one active shield member being driven, where the at least one active shield member defines a space that at least one of the first capacitive sensor plate and the second capacitive sensor plate is disposed within; where the controller is configured to drive the first capacitive sensor plate at a first amplitude, where the controller is configured to drive the second capacitive sensor plate at a second amplitude, where the controller is configured to drive the at least one active shield member at a third amplitude, and where the controller is configured to adjust the third amplitude relative to the first amplitude and the second amplitude. Implementations of the described techniques may include hardware, a method or process, or a computer tangible medium.

[0159] Certain terminology is used in the following description for convenience only and is not limiting. The words "right7’, "left”, "low er” and "upper” designate directions in the drawings to which reference is made. The w ords “inner”, "internal”, and “interior” refer to directions tow ards the geometric center of the capacitive gapping sensor system 40, while thewords “outer”, “external”, and “exterior” refer to directions away from the geometric center of the capacitive gapping sensor system 40. The terminology includes the above-listed words, derivatives thereof and words of similar import.

[0160] Although the disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Additionally, any of the embodiments disclosed herein can incorporate features disclosed with respect to any of the other embodiments disclosed herein. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments described in the specification. As one of ordinary skill in the art will readily appreciate from that processes, machines, manufacture, composition of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure.

[0161] For example, although Fig. 6 illustrates an embodiment of the capacitive gapping sensor system 40 that includes three capacitance sensors 50a, 50b, and 50c that are arranged in a circumferentially spaced manner about a longitudinal axis, the capacitance sensors 50a, 50b, and 50c could alternatively be shaped and / or arranged (e.g., in different non-circular shapes, in a different pattern, and / or in number fewer than three or greater than three). The various aspects and features described herein may be used alone or in any combination depending on the needs of the user. The disclosure in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.

Claims

What is Claimed:

1. A non-contact capacitive gapping sensor system, comprising: a housing that includes a monolithic housing body that defines a front end and a rear end that is offset from the front end; and a capacitance sensor that comprises a capacitive sensor plate that is configured to emit a first electric field, wherein the monolithic housing body defines a sensor cavity at the front end, and wherein the capacitance sensor is disposed within the sensor cavity such that the capacitance sensor is directed along a forward direction away from the front end and the rear end.

2. The non-contact capacitive gapping sensor system of claim 1, wherein the sensor cavity is at least partially defined by one or more stiffening ribs.

3. The non-contact capacitive gapping sensor system of claim 2, wherein the one or more stiffening ribs include at least two stiffening ribs that each extend along a first plane and are non-parallel with one another.

4. The non-contact capacitive gapping sensor system of claim 3, wherein the at least two stiffening ribs each extend along a respective one of at least two angularly offset axis that extend along the first plane and are angularly offset from one another by an acute angle.

5. The non-contact capacitive gapping sensor system of any one of claims 3 or 4, wherein the sensor cavity is a first sensor cavity, and wherein the at least two stiffening ribs includes three stiffening ribs that extend axially and together define a portion of the first sensor cavity, a second sensor cavity, and a third sensor cavity, each facing along the forward direction.

6. The non-contact capacitive gapping sensor system of claim 5, wherein the first sensor cavity7, the second sensor cavity', and the third sensor cavity are each identical shaped and sized, and wherein the first sensor cavity, the second sensor cavity, and the third sensor cavity- are each circumferentially spaced from one another by a respective one of the three stiffening ribs.

7. The non-contact capacitive gapping sensor system of any one of claims 5 or 6, wherein the at least two stiffening ribs includes an annularly extending stiffening rib that converges with a radially outer end of each of the three stiffening ribs.

8. The non-contact capacitive gapping sensor system of any one of claims 2 to 7, wherein each of the one or more stiffening ribs define a rear cavity that faces along a rearw ard direction opposite the forward direction.

9. The non-contact capacitive gapping sensor system of claim 8, further including a battery, a controller, and / or electronic device disposed within the rear cavity.

10. The non-contact capacitive gapping sensor system of any one of claims 2 to 9, further including at least two additional stiffening ribs that are each parallel to and circumferentially offset from a respective one of the at least two stiffening ribs.

11. The non-contact capacitive gapping sensor system of any one of claims 1 to 10, further comprising a first circuitry that is mounted underneath the capacitive sensor plate.

12. The non-contact capacitive gapping sensor system of any one of claims 1 to 11, wherein the monolithic housing body defines a rear facing cavity.

13. The non-contact capacitive gapping sensor system of any one of claims 1 to 12, wherein the capacitance sensor defines a non-circular outer perimeter.

14. The non-contact capacitive gapping sensor system of claim 13, wherein the noncircular outer perimeter, in a first plane, is concentric with a non-circular inner perimeter defined by the sensor cavity in the first plane.

15. The non-contact capacitive gapping sensor system of claim 14, wherein the non- circular outer perimeter and the non-circular inner perimeter each define an annular sector shape or each define a kidney bean shape.

16. The non-contact capacitive gapping sensor system of any one of claims 1 to 15. wherein the capacitance sensor includes an active shield member that is disposed within the sensor cavity and defines an interior space that the capacitance sensor plate is disposed within.

17. The non-contact capacitive gapping sensor system of any one of claims 1 to 16. wherein the monolithic housing body defines a circular outer perimeter.

18. The non-contact capacitive gapping sensor system of any one of claims 1 to 17, wherein the monolithic housing body defines a major surface that extends along a first plane, and an extent of an entirety of the monolithic housing body along an axis that is perpendicular to the first plane is anywhere from 1 millimeter (mm) to 10 mm, 2 mm to 10 mm, 2 mm to 9 mm, 2 mm to 8 mm, 2 mm to 7 mm, 2 mm to 6 mm, 2 mm to 5 mm, 2 mm to 4.5 mm, 2 mm to 4 mm, or 3 mm to 4 mm.

19. The non-contact capacitive gapping sensor system of any one of claims 1 to 18, further including a cover coupled to the rear end of the monolithic housing body, wherein the cover defines a planar surface that forms a planar rear end of the capacitive gapping sensor system.

20. The non-contact capacitive gapping sensor system of any one of claims 1 to 19, wherein the monolithic housing body is configured to shield circuitry of the capacitance sensor from a controller of the capacitive gapping sensor system.

21. The non-contact capacitive gapping sensor system of any one of claims 1 to 20, further comprising at least one active shield member that is configured to emit a second electric field such that the first electric field is directed toward a target object upon the at least one active shield member being driven, wherein the at least one active shield member defines a space that the capacitive sensor plate is disposed within; wherein the controller is configured to drive the capacitive sensor plate at a first amplitude, wherein the controller is configured to drive the at least one active shield member at a second amplitude, and wherein the controller is configured to adjust the second amplitude relative to the first amplitude.

22. The non-contact capacitive gapping sensor system of any one of claims 1 to 21. wherein the capacitive sensor plate is a first capacitive sensor plate, and wherein the non-contact capacitive gapping sensor system further comprises: a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven; and a controller that in a first mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously and / or in a second mode is configured to drive the first capacitive sensor plate differently from the second capacitive sensor plate.

23. A method of using the non-contact capacitive gapping sensor system of any one of claims 1 to 22, comprising: driving first capacitive sensor plate at the first amplitude to emit the first electric field toward a target object; sensing a first capacitance between the first capacitive sensor plate and the target object; and determining a gap between the first capacitive sensor plate and the target object based on the first capacitance.

24. The method of claim 23, further comprising: wirelessly transmitting sensing data, which is based on the sensed first capacitance, to an external device.

25. A non-contact capacitive gapping sensor system, comprising: a housing; a capacitance sensor that comprises: a capacitive sensor plate configured to emit a first electric field upon being driven at a first amplitude; and an active shield member that is configured to emit a second electric field such that first electric field is directed toward a target object upon the active shield member being driven at a second amplitude, wherein the active shield member defines a space that the capacitive sensor plate is disposed within; and a controller that is configured to drive the active shield member and the capacitive sensor plate, wherein the controller is configured to drive the active shield member at the secondamplitude and is configured to drive the capacitive sensor plate at the first amplitude, and wherein the controller is configured to adjust the second amplitude relative to the first amplitude.

26. The non-contact capacitive gapping sensor system of claim 25, wherein the second amplitude is different from the first amplitude.

27. The non-contact capacitive gapping sensor system of any one of claims 25 or 26, wherein the housing is wafer-shaped such that the capacitive gapping sensor system is wafershaped.

28. The non-contact capacitive gapping sensor system of any one of claims 25 to 27, wherein the controller is configured to tune the active shield member by adjusting the second amplitude such that the capacitance sensor has a sensitivity above a predetermined threshold.

29. The non-contact capacitive gapping sensor system of any one of claims 25 to 28, wherein the controller is configured to drive the active shield member based on the first amplitude and / or a predetermined desired sensitivity level of the capacitance sensor.

30. The non-contact capacitive gapping sensor system of any one of claims 25 to 29, wherein the active shield member comprises defines a non-circular inner perimeter in a plane that is parallel and offset from a major surface of the capacitive sensor plate.

31. The non-contact capacitive gapping sensor system of any one of claims 25 to 30, wherein the capacitive sensor plate forms a sensing pad.

32. The non-contact capacitive gapping sensor system of any one of claims 25 to 31, wherein the housing is electrically coupled to the active shield member such that the housing and the active shield member form an active shield that directs the first electric field to the target object.

33. The non-contact capacitive gapping sensor system of any one of claims 25 to 32, wherein the capacitance sensor is a first capacitive sensor, and wherein the capacitive gapping sensor further includes a second capacitive sensor and / or a third capacitive sensor.

34. The non-contact capacitive gapping sensor system of any one of claims 25 to 33, wherein the housing is formed by a monolithic body.

35. The non-contact capacitive gapping sensor system of any one of claims 25 to 34, wherein the capacitive gapping sensor comprises a wireless transceiver.

36. The non-contact capacitive gapping sensor system of any one of claims 25 to 35, wherein the capacitive gapping sensor comprises a controller.

37. A non-contact capacitive gapping sensor system, comprising: a housing; a first capacitance sensor that comprises: a first capacitive sensor plate configured to emit a first electric field upon being driven; a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven; and a controller that in a first mode is configured to drive the first capacitive sensor plate differently from the second capacitive sensor plate.

38. The non-contact capacitive gapping sensor system of any one of claim 37, wherein the housing is wafer-shaped such that the capacitive gapping sensor system is wafershaped.

39. The non-contact capacitive gapping sensor system of any one of claims 37 or 38, wherein the first capacitive sensor plate defines a non-circular outer perimeter.

40. The non-contact capacitive gapping sensor system of any one of claims 37 to 39, further comprising a first circuitry that is mounted underneath the first capacitive sensor plate, and a second circuitry that is mounted underneath the second capacitive sensor plate.

41. The non-contact capacitive gapping sensor system of any one of claims 37 to 40, wherein in the first mode the controller is configured to drive the first capacitive sensor plate with a first electric current, while the second capacitive sensor plate is not driven.

42. The non-contact capacitive gapping sensor system of claim 41, further comprising a third capacitance sensor that comprises a third capacitive sensor plate that is configured to emit a third electric field upon being driven, wherein in the first mode the controller is configured to drive only one of the first capacitive sensor plate, the second capacitive sensor plate, or the third capacitive sensor plate at a time at a first amplitude, and drive others of the first capacitive sensor plate, the second capacitive sensor plate, or the third capacitive sensor plate at 0 volts.

43. The non-contact capacitive gapping sensor system of any one of claims 37 to 42, wherein in the first mode the controller is configured to drive the first capacitive sensor plate with a first electric current that is out of phase with a second electric current that drives the second capacitive sensor plate.

44. The non-contact capacitive gapping sensor system of any one of claims 37 to 43, wherein in the first mode the controller is configured to drive the first capacitive sensor plate with a first alternating current voltage and drive the second capacitive sensor plate with a second alternating current voltage, wherein the controller is configured to swing the first alternating cunent voltage and the second alternating current voltage relative to a predetermined voltage.

45. The non-contact capacitive gapping sensor system of any one of claims 37 to 44, wherein in a second mode the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously at a first amplitude.

46. The non-contact capacitive gapping sensor system of any one of claims 37 to 45, further comprising a third capacitance sensor that comprises a third capacitive sensor plate that is configured to emit a third electric field upon being driven, wherein in the first mode the controller is configured to drive the first capacitive sensor plate and the third capacitive sensor plate simultaneously at a first amplitude, and drive the second capacitive sensor plate at a second amplitude that is different from the first amplitude.

47. The non-contact capacitive gapping sensor system of claim 46, wherein in the first mode, the second amplitude is 0 volts.

48. The non-contact capacitive gapping sensor system of any one of claims 46 or 47, wherein in the first mode the controller is configured transition from a first stage, wherein the controller is configured to simultaneously driving the first capacitive sensor plate and the third capacitive sensor plate at the first amplitude, to a second stage wherein the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate at a third amplitude, and drive the third capacitive sensor plate at a fourth amplitude that is different from the third amplitude.

49. The non-contact capacitive gapping sensor system of claim 48, wherein the third amplitude is equal to the first amplitude, and the fourth amplitude is equal to the second amplitude.

50. The non-contact capacitive gapping sensor system of any one of claims 48 or 49, wherein in the first mode the controller is configured transition from the second stage to a third stage wherein the controller is configured to drive the second capacitive sensor plate and the third capacitive sensor plate at a fifth amplitude, and drive the first capacitive sensor plate at a sixth amplitude that is different from the fifth amplitude.

51. The non-contact capacitive gapping sensor system of claim 50, wherein the fifth amplitude is equal to the first amplitude, and the sixth amplitude is equal to the second amplitude.

52. The non-contact capacitive gapping sensor system of any one of claims 37 to 51, further comprising at least one additional capacitance sensor that is configured to emit at least a third electric field upon being driven.

53. The non-contact capacitive gapping sensor system of any one of claims 37 to 52, further comprising at least one active shield member that is configured to emit a third electric field such that the first electric field and / or the second electric field is directed toward a target obj ect upon the at least one active shield member being driven, wherein the at least one active shield member defines a space that at least one of the first capacitive sensor plate and the second capacitive sensor plate is disposed within; wherein the controller is configured to drive the first capacitive sensor plate at a first amplitude, wherein the controller is configured to drive the second capacitive sensor plate at asecond amplitude, wherein the controller is configured to drive the at least one active shield member at a third amplitude, and wherein the controller is configured to adjust the third amplitude relative to the first amplitude and the second amplitude.

54. A non-contact capacitive gapping sensor system, comprising: a housing: a first capacitance sensor that comprises: a first capacitive sensor plate configured to emit a first electric field upon being driven; a second capacitance sensor that comprises: a second capacitive sensor plate configured to emit a second electric field upon being driven; and a controller that in a first mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously.

55. The non-contact capacitive gapping sensor system of claim 54, wherein the housing is wafer-shaped such that the capacitive gapping sensor system is wafer-shaped.

56. The non-contact capacitive gapping sensor system of any one of claims 54 or 55, wherein the first capacitive sensor plate and / or the second capacitive sensor plate are configured with a non-circular outer perimeter.

57. The non-contact capacitive gapping sensor system of any one of claims 54 to 56, further comprising a first circuitry that is mounted underneath the first capacitive sensor plate, and a second circuitry that is mounted underneath the second capacitive sensor plate.

58. The non-contact capacitive gapping sensor system of any one of claims 54 to 57, wherein the controller is configured to drive the first capacitive sensor plate and the second capacitive sensor plate simultaneously at a first amplitude.

59. The non-contact capacitive gapping sensor system of any one of claims 54 to 58, wherein the controller in a second mode is configured to drive the first capacitive sensor plate and the second capacitive sensor plate, wherein the first capacitive sensor plate is driven with afirst electnc current that is out of phase with a second electric current that drives the second capacitive sensor plate.

60. The non-contact capacitive gapping sensor system of any one of claims 54 to 59, further comprising at least one additional capacitance sensor that is configured to emit a third electric field upon being driven.

61. The non-contact capacitive gapping sensor system of claim 60, wherein the controller is configured to drive each of the first capacitance sensor, the second capacitance sensor, and the additional capacitance sensor with a same driver at a same amplitude.

62. The non-contact capacitive gapping sensor system of any one of claims 54 to 61, further comprising at least one active shield member that is configured to emit a third electric field such that the first electric field and / or the second electric field is directed toward a target object upon the at least one active shield member being driven, wherein the at least one active shield member defines a space that at least one of the first capacitive sensor plate and the second capacitive sensor plate is disposed within; wherein the controller is configured to drive the first capacitive sensor plate at a first amplitude, wherein the controller is configured to drive the second capacitive sensor plate at a second amplitude, wherein the controller is configured to drive the at least one active shield member at a third amplitude, and wherein the controller is configured to adjust the third amplitude relative to the first amplitude and the second amplitude.

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