RF measurement from transmission line sensors

Abstract

Embodiments disclosed herein include a sensor, in one embodiment, that includes a board with an aperture formed therethrough, a current loop passing through the board so as to wrap around the aperture, and a voltage ring around the aperture and on an inner circumference of the current loop, the voltage ring including an inner ring, an insulating ring around the inner ring, and an outer ring around the insulating ring.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Patent Application No. 17 / 737,682, filed on May 5, 2022, the entire content of which is incorporated herein by reference.

[0002] Embodiments relate to the field of semiconductor manufacturing, and more particularly, to sensors for measuring voltage and current within a semiconductor tool.

Background Art

[0003] In plasma processing tools, plasma is ignited by a cathode coupled to a process gas within a chamber. In most tools, the power supply is coupled to the cathode via an impedance matching network (sometimes simply referred to as a "matcher"). The matcher enables adjustment of the system impedance for matching with the impedance of the load to which the cathode is coupled. The load has a wide range of impedances defined by parameters such as processing conditions and chamber structure. Impedance matching is important for efficient power transfer from the power supply to the load.

[0004] RF coupling sensors are used to change an impedance variation device and provide feedback for changing the impedance of the matcher. However, current sensors have problems. One problem is that the parasitic effects are not well - controlled, so the effective operating frequency is limited. Additionally, the parasitics of the sensor and the mutual coupling of ports degrade the dynamic range of the sensor due to mutual coupling. Yet another problem is that multiple sensors built on a common printed circuit board (PCB) may cause coupling between the sensors, thereby degrading the sensor measurements in some cases.

Summary of the Invention

[0005] Embodiments disclosed herein include sensors. In one embodiment, the sensor comprises a board formed through which an aperture passes, a current loop passing through the board so as to wrap around the aperture, and a voltage ring located around the aperture and on the inner circumference of the current loop, wherein the voltage ring comprises an inner ring, an insulating ring around the inner ring, and an outer ring around the insulating ring.

[0006] In additional embodiments, a sensor is described. In one embodiment, the sensor is a board through which an aperture is provided; a current loop around the aperture, comprising a current loop having an inner pair of vias, an outer pair of vias, and a plurality of conductive traces, each conductive trace connecting a via from the inner pair of vias to a via from the outer pair of vias, with the plurality of conductive traces alternately arranged on the top surface of the board and the bottom surface of the board; and a voltage ring on the inner circumference of the current loop, comprising an inner ring, an insulating ring around the inner ring, and an outer ring around the insulating ring.

[0007] In one embodiment, a processing tool is described. In one embodiment, the processing tool comprises a power supply, an impedance matching network connected to the power supply, a cathode, the power supply being configured to supply power to the cathode via the impedance matching network, a processing module communicatively connected to the cathode, a first sensor located upstream of the impedance matching network, and a second sensor located downstream of the impedance matching network, wherein the first sensor and the second sensor each comprise a board formed such that an aperture passes through it, a current loop passing through the board so as to wrap around the aperture, and a voltage ring located around the aperture and on the inner circumference of the current loop, the voltage ring comprising an inner ring, an insulating ring around the inner ring, and an outer ring around the insulating ring. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a plasma processing tool including a central control architecture according to an embodiment. [Figure 2A] This is a plan view of the sensor's current loop according to the embodiment. [Figure 2B] This is a plan view of the voltage ring of the sensor according to the embodiment. [Figure 3A] This is a plan view of a sensor having a current loop, a voltage ring, and a protective ring according to an embodiment. [Figure 3B] This is a plan view of a printed circuit board having a pair of sensors according to an embodiment. [Figure 4A] This is a plan view of a sensor having a plurality of baluns connected to a current loop, according to an embodiment. [Figure 4B] This is a circuit diagram of a balun that may be used in a sensor according to this embodiment. [Figure 5A] This is a perspective view of the sensor according to this embodiment. [Figure 5B] This is a perspective view of a grounding plate having a cutout for a sensor according to an embodiment. [Figure 5C] This is a perspective view of a sensor inserted into a grounding plate according to an embodiment. [Figure 6A] This is a plan view of a grounding plate for a symmetric cathode including a notch for a sensor, according to an embodiment. [Figure 6B] This is a plan view of a grounding plate having a sensor inserted into a notch, according to an embodiment. [Figure 7] A block diagram of an exemplary computer system that may be used in conjunction with a processing tool, according to one embodiment, is shown. [Modes for carrying out the invention]

[0009] The systems described herein include sensors for measuring voltage and current in semiconductor tools from transmission line sensors. Numerous specific details are presented in the following description to provide a comprehensive understanding of the embodiments. Those skilled in the art will see that embodiments can be carried out without these specific details. In other cases, well-known embodiments are not described in detail to avoid unnecessarily obscuring the embodiments. Furthermore, it should be understood that the various embodiments shown in the accompanying figures are illustrative and not necessarily drawn to scale.

[0010] As described above, existing sensor devices have limitations. Therefore, impedance matching networks do not operate under ideal conditions. Accordingly, embodiments disclosed herein include sensors with improved performance. As used herein, a sensor may refer to a sensor capable of measuring current and / or voltage along a coaxial transmission line section. In certain embodiments, the sensor includes an aperture through which a conductive device (e.g., an RF cable) having concentrically arranged electrical insulating material passes. Features on the sensor are capable of picking up current and voltage passing along the transmission line. For example, a current loop picks up current and a voltage ring detects voltage. The current and voltage measurements can be used as sensor measurement feedback to direct changes in the impedance of the impedance matching network.

[0011] In certain embodiments, the sensors described herein exhibit a reduction in parasitic coupling between pickup elements. This allows for a larger dynamic range over a wider operating frequency range. In some embodiments, a balun is included along the current loop. This allows for increased magnetic field coupling and amplification of current loop induction. In yet another embodiment, isolation between sensor pickup elements (for current and voltage) reduces mutual coupling between sensor supports. This allows for a larger dynamic range over a wider operating frequency range. Some embodiments may include multiple sensors on a single printed circuit board (PCB). In such embodiments, protective rings may be provided around each sensor to eliminate mutual coupling between concentric sensor elements. This allows for high-fidelity measurement and accuracy over a wider dynamic range, while simultaneously extending the frequency range.

[0012] In certain embodiments, the sensors described herein are part of a plasma processing tool. Generally, a plasma processing tool includes a chamber having a cathode. A power architecture supplies power to the cathode. For example, the power architecture includes one or more power supplies and impedance matching networks. The sensors described herein may be located upstream and / or downstream of the impedance matching network. The sensors may supply feedback to a processing power processing module that controls the bulk and sheath voltages of the plasma and the power supplies connected to the impedance matching network.

[0013] Referring now to Figure 1, a more detailed schematic diagram of a plasma processing tool 100 according to an embodiment is shown. In one embodiment, the plasma processing tool 100 includes a plasma chamber 120. The plasma chamber 120 includes a cathode 122 for coupling the received power to one or more gases flowing into the plasma chamber 120. In one embodiment, the plasma chamber 120 may be suitable for any plasma processing typical of a semiconductor manufacturing environment. For example, the plasma chamber 120 may be a plasma etching chamber, a plasma deposition chamber, a plasma processing chamber, etc. In a particular embodiment, the plasma chamber 120 may be a plasma chemical vapor deposition (PECVD) chamber, a physical vapor deposition (PVD) chamber, or a plasma-enhanced atomic layer deposition (PEALD) chamber.

[0014] In one embodiment, the plasma chamber 120 may be connected to a power supply architecture. For example, the power supply architecture may consist of one or more power supplies 1321-132 n This may include. In the illustrated embodiments, multiple power supplies 132 are shown. However, it should be understood that in some embodiments, a single power supply 132 may be used. In one embodiment, power supply 132 may include any type of power supply. For example, power supply 132 may be an RF power supply, a microwave power supply, a direct current (DC) power supply, a pulsed DC power supply, etc. Transmission line sensors with an expanded dynamic range and widened operating frequency response enable plasma drive power supplies for a wider corpus.

[0015] In one embodiment, the power supply 132 may be connected to the cathode 122 via an impedance matching network 130. The impedance matching network 130 adjusts the impedance of the power supply architecture to match the load within the chamber 120. Due to changes in processing conditions (e.g., gas flow rate, pressure, temperature, etc.), the impedance of the load may vary. Therefore, the impedance matching network 130 is used to match the varying impedance in order to provide an efficient and optimal (i.e., in a state where there is no or minimal reflected power) power supply to the coupled plasma within the chamber.

[0016] In one embodiment, sensors 151 and 152 may be provided on both sides of the impedance matching network 130. For example, sensor 1511 - 151 n may be on the upstream side of the impedance matching network 130, and sensor 152 may be on the downstream side of the impedance matching network 130. The "upstream" side refers to the input side of the impedance matching network 130, and the "downstream" side refers to the output side of the impedance matching network 130. As shown in the figure, multiple sensors 1511 - 151 n are provided on the upstream side of the impedance matching network 130. The number of sensors 151 may be equal to the number of power supplies 132. That is, each power supply 132 has a dedicated sensor 151. The downstream side of the impedance matching network 130 may have a single sensor 152. However, it should be understood that if there are more than one output from the matching network 130, additional sensors 152 may exist. For example, if there are two outputs (e.g., for the center of the chamber 120 and the end of the chamber 120), there may be two sensors 152.

[0017] When there are multiple sensors 151, the multiple sensors 151 1-ncan be manufactured on a single PCB. That is, a single module can include multiple sensors. A more detailed description of embodiments of multiple sensors is provided below. Generally, the embodiments described herein include an electrical shielding technique that limits the mutual coupling between sensors on a single PCB.

[0018] In FIG. 1, sensors 151 and 152 are generally shown as blocks. However, it should be understood that sensors 151 and 152 can be similar to any of the sensor architectures described in more detail below. For example, each sensor 151 and / or 152 can be a voltage and current (i.e., V / I) sensor. The voltage can be detected by an embedded voltage ring, and the current can be detected by a current loop. Each sensor has an aperture through which a conductive device (e.g., an RF cable) having concentric electrical insulating material passes.

[0019] In one embodiment, sensors 151 and 152 can be communicatively coupled to a processing module 134. As shown, a general-purpose processing power control module 134 is provided in FIG. 1. However, it should be understood that the processing module can be a microwave processing module 134, a DC processing module, an RF processing module, etc., depending on the type of power supply 132 included in tool 100. In one embodiment, sensors 151 and 152 supply voltage and / or current to processing module 134. In one embodiment, processing power control module 134 can have external connections for various physical layers and protocols, such as standard industrial connections like Ethernet (ENET) and EtherCAT.

[0020] In one embodiment, the processing module 134 may be connected to an impedance matching network. The processing module 134 may be capable of transmitting control signals to the impedance matching network 130. For example, the control signals may be used to adjust the capacitance of a variable capacitor in the impedance matching network 130. Furthermore, the processing module 134 may be connected to a power supply 132. Thus, the processing module 134 is capable of coordinated impedance adjustment.

[0021] Referring now to Figure 2A, a partial plan view of the sensor 250 according to an embodiment is shown. In one embodiment, the sensor 250 may include a PCB 253. The PCB 253 may include two or more routing layers. Each routing layer may be separated from one another by a dielectric layer. In one embodiment, vias may pass through the dielectric layer to provide electrical coupling between the routing layers.

[0022] In one embodiment, the sensor 250 may include a current loop 254. The current loop 254 may include one or more conductive windings that surround the aperture 260 through the PCB 253. In the particular embodiment shown in Figure 2A, the current loop 254 includes two windings. However, it should be understood that in other embodiments, a single winding or more than two windings may be used. In one embodiment, each winding consists of a trace 257 (solid line) on the top surface of the PCB 253 and a trace 256 (dashed line) on the bottom surface of the PCB 253. Transitions through the PCB 253 may be provided by vias 255. As shown, a first concentric ring of via 255A and a second concentric ring of via 255B are provided around the aperture 260. Each via 255 is paired with via 255B. In some cases, via 255A may be called an outer via and via 255B may be called an inner via.

[0023] As shown in the figure, the windings are alternately implemented as traces 256 on the top surface of PCB253 and as traces 257 on the bottom surface of PCB253. Furthermore, each winding is alternately arranged between the inner vias 255B and the outer vias 255A. In addition, the windings intersect with each other. For example, between a first pair of vias 255A and 255B and an adjacent second pair of vias 255A and 255B, the first winding may pass along the top surface of PCB253 as trace 256, and the second winding may pass along the bottom surface of PCB253 as trace 257.

[0024] In one embodiment, the first end of the current loop 254 may be connected to the pad 2591 by a trace 258. Similarly, the second end of the current loop 254 may be connected to the pad 2592 by a trace 258. In one embodiment, the first end and the second end of the current loop 254 may be located on the same plane of the PCB 253. For example, in Figure 2A, the pads 2591 and 2592 are located on the upper surface of the PCB 253.

[0025] In the illustrated embodiment, 16 inner vias 255B and 16 outer vias 255A (32 vias 255 in total) are shown. However, it should be understood that more or fewer vias 255 may be used depending on the various embodiments. In certain embodiments, there may be 24 inner vias 255B and 24 outer vias 255 (48 vias 255 in total). In some cases, increasing the number of vias 255 can increase the degree of coupling with the magnetic field of the cable through the aperture 260. This can improve the performance of the sensor.

[0026] Referring now to Figure 2B, a partial plan view of the sensor 250 according to the embodiment is shown. In one embodiment, the sensor 250 in Figure 2B shows a voltage pickup structure. For example, an embedded voltage ring 265 may be inserted within a PCB 253 surrounding an aperture 260. More specifically, it should be noted that the voltage ring 265 is physically inserted within the PCB 253 and is not etched from the conventional PCB material. This allows for the fabrication of a 3D type PCB assembly. Although shown as separate sensors 250 for clarity, it will be understood that the current loop 254 and the voltage ring 265 may be mounted on a single PCB 253. In such embodiments, the voltage ring 265 may be provided around the aperture 260 within the inner circumference of the current loop 254.

[0027] In one embodiment, the voltage ring 265 may include a first conductive ring 266 and a second conductive ring 268. In one embodiment, an insulating ring 267 may be provided between the first conductive ring 266 and the second conductive ring 268. In certain embodiments, the first conductive ring 266 and the second conductive ring 268 may be made of copper or another conductive material. The first conductive ring 266 and the second conductive ring 268 may be concentric rings. The thickness of the first conductive ring 266 and the second conductive ring 268 may be substantially equal to the thickness of the PCB 253.

[0028] In one embodiment, the first ring 266 may be used as a voltage pickup surface. The second ring 268 may be grounded; that is, the second ring 268 may be connected to electrical ground. Although not shown, it will be understood that tabs connected to either the first ring 266 and / or the second ring 268 may be folded over the top and / or bottom surfaces of the insulating ring 267. In one embodiment, the embedded voltage ring 265 is concentric with respect to the aperture 260 that penetrates the PCB 253. In one embodiment, the embedded voltage ring 265 is fitted into the aperture 260. In other embodiments, the embedded voltage ring is embedded internally within the base structure of the PCB 253.

[0029] Referring now to Figure 3A, a plan view of the sensor 350 according to the embodiment is shown. As shown, the sensor 350 is fabricated on a PCB 353. The sensor 350 may include a current loop 354 and a voltage ring 365 within the current loop 354. The current loop 354 and the voltage ring 365 may penetrate the PCB 353 and surround an aperture 360.

[0030] In one embodiment, the current loop 354 may include an inner via 355B and an outer via 355A. The vias 355 may be connected to each other by traces 356 on the top surface of the PCB 353 and by traces 357 on the bottom surface of the PCB 353. In the illustrated embodiment, the current loop 354 includes a pair of windings around the aperture 360. In one embodiment, the current loop 354 may be substantially similar to the current loop 254 described in more detail above.

[0031] In one embodiment, the voltage ring 365 may include an inner conductive ring 366 and an outer conductive ring 368. An insulating ring 367 may be provided between the inner ring 366 and the outer ring 368. The inner ring 366 may be a voltage pickup surface, and the outer ring 368 may be grounded. In one embodiment, the inner ring 366 may define the outer circumference of the aperture 360. The voltage ring 365 may be substantially similar to the voltage ring 265 described in more detail above.

[0032] In one embodiment, the sensor 350 may further include a protective ring 370 surrounding the outer circumference of the current loop 354. In one embodiment, the protective ring 370 may be grounded. The protective ring 370 may include vias (not shown) that connect the protective ring 370 to a ring on the bottom surface of a PCB 353 having a similar size and shape. Thus, an electrical shielding barrier is provided around the pickup component of the sensor 350. This can improve sensor performance.

[0033] In one embodiment, the voltage ring 365 may be connected to a pickup circuit 381 on the PCB 353. The pickup circuit 381 in Figure 3 is schematically shown as a dashed box. However, it should be understood that the pickup circuit 381 may include features such as filters and amplifiers. In one embodiment, a pad 383 is provided. The pad 383 may be suitable for mounting a connector (not shown) to feed back voltage information to a processing module (e.g., a processing module described in more detail above).

[0034] In one embodiment, the current loop 354 may be connected to a pickup circuit 382 on the PCB 353. The pickup circuit 382 in Figure 3A is schematically shown as a dashed box. However, it should be understood that the pickup circuit 382 may include features such as filters and amplifiers. In one embodiment, a pad 384 is provided. The pad 384 may be suitable for mounting a connector (not shown) to feed back current information to a processing module (e.g., a processing module described in more detail above).

[0035] In one embodiment, pickup circuit 381 is electrically isolated from pickup circuit 382. The two sets of pickup circuits 381 and 382 allow for reduced interconnection between the two circuits, thereby improving the performance of the sensor 350. In one embodiment, electrical isolation can be achieved by a conductive strip 385 provided between the two sets of pickup circuits 381 and 382. In one embodiment, the conductive strip 385 may be grounded. In some embodiments, the conductive strip 385 is electrically connected to a protective ring 370. The conductive strip 385 may be provided on the top surface of the PCB 353. In other embodiments, vias may be provided below the strip 385 to extend the electrical isolation through the thickness of the PCB 353.

[0036] Referring now to Figure 3B, a plan view of sensor 350 according to an additional embodiment is shown. In the embodiment shown in Figure 3B, sensor 350 may include a pair of apertures 3601 and 3602. Each aperture 360 ​​may be surrounded by a current loop 354 and a voltage ring 365. For example, a current loop 3541 and a voltage ring 3651 are around aperture 3601, and a current loop 3542 and a voltage ring 3652 are around aperture 3602. Similarly, a first protection ring 3701 may be around current loop 3541, and a second protection ring 3702 may be around current loop 3542. Although two sets of pickup elements are shown, it will be understood that any number of apertures 360 and corresponding current loops 354, voltage rings 365, and protection rings 370 may be included on PCB 353. The current loop 354 and voltage ring 365 may be substantially similar to the current loop 254 and voltage ring 265 described in more detail above.

[0037] As shown in Figure 3B, the protective ring 370 includes vias 371. Via 3711 is located below protective ring 3701, and via 3712 is located below protective ring 3702. In one embodiment, the positions of vias 3711 and 3712 may be rotated relative to each other. Rotation of the orientation of via 371 may result in greater electrical isolation between the two sets of pickup elements.

[0038] In one embodiment, the voltage ring 3651 may be connected to the pickup circuit 3811 and pad 3831, and the current loop 3541 may be connected to the pickup circuit 3821 and pad 3841. Similarly, the voltage ring 3652 may be connected to the pickup circuit 3812 and pad 3832, and the current loop 3542 may be connected to the pickup circuit 3822 and pad 3842. The pickup circuits 381 / 382 may be substantially similar to the pickup circuits described in more detail above.

[0039] Conductive strips 3851 and 3852 may be provided to provide electrical isolation between the various instances of the pickup circuits 381 / 382. Conductive strip 386 may be provided to provide electrical isolation between pickup circuits 3821 and 3812. Conductive strips 385 and 386 may be on the upper surface of PCB 353. In another embodiment, vias below conductive strip 385 can extend the electrical isolation through the thickness of PCB 353. In one embodiment, conductive strips 385 and 386 can be grounded.

[0040] Referring now to Figure 4A, a plan view of a sensor 450 according to an embodiment is shown. In one embodiment, the sensor 450 may comprise a PCB 453 having an aperture 460. In one embodiment, the pickup element may include a current loop 454 and a voltage ring 465. The current loop 454 and voltage ring 465 may be substantially similar to the current loop and voltage ring described in more detail above. In one embodiment, the sensor 450 may further comprise a protective ring 470 surrounding the outer circumference of the current loop 454.

[0041] In one embodiment, the current loop 454 may be electrically connected to one or more baluns 475. In Figure 4, the balun 475 is shown to be installed in a notch within a protective ring 475. However, it should be understood that the baluns 475 may be installed in any convenient location on the PCB 453. In the illustrated embodiment, four baluns 475 are provided. However, it should be understood that any number of baluns 475 may be used. The presence of baluns 475 can increase the signal-to-noise ratio and improve the performance of the sensor. In certain embodiments, each balun 475 can double the current. In one embodiment, transformers are evenly distributed in each loop, and each transformer is geometrically positioned 180 degrees opposite its pair. For example, four transformers are arranged with one pair per loop, and the pairs are 180 degrees apart circumferentially from each other.

[0042] Referring now to Figure 4B, an electrical circuit of a balun 475 according to an embodiment is shown. In one embodiment, the balun 475 may include a transformer-based circuit. While Figure 4B shows a specific architecture of the balun 475, it should be understood that the circuit of the balun 475 may include any suitable structure that provides the function of a balun.

[0043] Referring now to Figure 5A, a plan view of the sensor 550 according to an embodiment is shown. In one embodiment, the sensor 550 may include an approximately circular end 547 and a rectangular end 548. The circular end 547 may include an aperture 560 through which cables and the like pass. In one embodiment, a current loop and a voltage ring (neither of which are shown for simplicity) are provided around the aperture 560. In one embodiment, the rectangular end 548 may be used to support a pickup circuit and a connector.

[0044] Referring now to Figure 5B, a plan view of a grounding plate 590 of a fixed cathode device according to an embodiment is shown. As shown, the grounding plate 590 may include a notch 591 that substantially conforms to the shape of the sensor 550. The notch 591 may have a depth that substantially conforms to (or greater than) the thickness of the sensor 550. In one embodiment, the notch 591 covers an aperture 561 that penetrates the grounding plate 590. The aperture 561 may be a location where an electrical cable (e.g., an RF cable) passes through the grounding plate 590.

[0045] Referring now to Figure 5C, a plan view of the grounding plate 590 after the sensor 550 has been inserted, according to the embodiment. As shown, the aperture 560 within the sensor 550 is aligned with the aperture 561, allowing the cable to pass through. The cable triggers the detection of current and voltage by the sensor's pickup surface (e.g., current loop and voltage ring), and this current and voltage are fed back to the processing power processing module. For example, this feedback may be used in part to control an impedance matching network or processing power that contributes to the plasma density and / or plasma sheath voltage.

[0046] Referring now to Figure 6A, a plan view of a grounding plate 695 for a symmetric cathode according to the embodiment is shown. Similar to the embodiments described in Figures 5A to 5C, the grounding plate 695 may include a notch 691 sized to receive the sensor.

[0047] Referring now to Figure 6B, the grounding plate 695 after the sensor 650 has been inserted into the notch 691 according to the embodiment is shown. As shown, the aperture 660 of the sensor 650 is positioned to receive a cable. The voltage and current of the cable can be measured by the sensor 650.

[0048] While two examples of sensor integration into plasma tools are shown, it should be understood that embodiments are not limited to such configurations. For example, other plasma tool architectures may require moving sensors to various locations other than the grounding plate. Furthermore, as described in more detail above, similar sensor architectures may be used to measure current and voltage in front of an impedance matching network. That is, embodiments generally include sensors that measure current and voltage through the use of current loops and voltage rings formed concentrically around the aperture.

[0049] Referring here to Figure 7, a block diagram of an exemplary computer system 700 of a processing tool is shown according to an embodiment. In one embodiment, the computer system 700 is connected to a processing tool and controls the processing within the processing tool. The computer system 700 may be connected to (e.g., networked) other machines in a local area network (LAN), intranet, extranet, or internet. In a client-server network environment, the computer system 700 may operate as a server or a client machine, or in a peer-to-peer (or distributed) network environment, it may operate as a peer machine. The computer system 700 may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile phone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or different) that specify the actions performed by that machine. Furthermore, although only a single machine is shown as computer system 700, the term “machine” should be further interpreted to include any collection of machines (e.g., computers) that individually or in conjunction execute a set (or set) of instructions in order to carry out any one or more of the methods described herein.

[0050] The computer system 700 may include a computer program product or software 722 having a non-transient machine-readable medium on which instructions are stored, and these instructions may be used to program the computer system 700 (or other electronic device) to perform processing according to the embodiment. The machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, the machine-readable (e.g., computer-readable) medium includes machine (e.g., computer)-readable storage media (e.g., read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.), machine (e.g., computer)-readable transmission media (in the form of electrical, optical, acoustic, or other propagating signals (e.g., infrared signals, digital signals, etc.)), etc.

[0051] In one embodiment, the computer system 700 includes a system processor 702, main memory 704 (e.g., read-only memory (ROM), flash memory, synchronous DRAM (SDRAM), or rhombus DRAM (RDRAM) or other dynamic random access memory (DRAM)), static memory 706 (e.g., flash memory, static random access memory (SRAM), etc.), and secondary memory 718 (e.g., a data storage device), all of which communicate with each other via a bus 730.

[0052] The system processor 702 represents one or more general-purpose processing devices, such as a microsystem processor or a central processing unit. More specifically, the system processor may be a composite instruction set arithmetic (CISC) microsystem processor, a reduced instruction set arithmetic (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor that executes other instruction sets, or a system processor that executes a combination of instruction sets. The system processor 702 may also be one or more special-purpose processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal system processor (DSP), or a network system processor. The system processor 702 is configured to execute processing logic 726 for performing the operations described herein.

[0053] The computer system 700 may further include a system network interface device 708 for communicating with other devices or machines. The computer system 700 may further include a video display unit 710 (e.g., a liquid crystal display (LCD), a light-emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 712 (e.g., a keyboard), a cursor control device 714 (e.g., a mouse), and a signal generation device 716 (e.g., a speaker).

[0054] The secondary memory 718 may include a machine-accessible storage medium 732 (or, more specifically, a computer-readable storage medium) storing one or more sets of instructions (e.g., software 722) that embody any one or more of the methods or functions described herein. The software 722 may also reside, all or at least partially, in the main memory 704 and / or the system processor 702 while being executed by the computer system 700, and the main memory 704 and the system processor 702 may also constitute a machine-readable storage medium. The software 722 may be further transmitted and received over the network 720 via the system network interface device 708. In one embodiment, the network interface device 708 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

[0055] Although the machine-accessible storage medium 732 is shown as a single medium in one exemplary embodiment, the term “machine-readable storage medium” should be interpreted to include one or more mediums (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. Furthermore, the term “machine-readable storage medium” should be interpreted to include any medium capable of storing or encoding a set of instructions executed by a machine, and causing the machine to execute one or more of these methods. Therefore, the term “machine-readable storage medium” should be interpreted to include, but not be limited to, solid memory, optical media, and magnetic media.

[0056] The above specification describes specific exemplary embodiments. It will be apparent that various modifications can be made to these exemplary embodiments without departing from the scope of the following claims. Therefore, this specification and the drawings should be considered illustrative, not limiting.

Claims

1. It is a sensor, A board formed so that an aperture penetrates through it. A current loop passing through the board, wrapped around the aperture, A voltage ring located around the aperture and on the inner circumference of the current loop, The inner ring, An insulating ring around the aforementioned internal ring, The outer ring around the aforementioned insulating ring and A voltage ring equipped with A protective ring around the current loop, and One or more baluns in each of the notches in the protective ring, one or more baluns electrically connected to the current loop, A sensor equipped with this feature.

2. The sensor according to claim 1, wherein the current loop comprises a first winding and a second winding.

3. The sensor according to claim 1, wherein the current loop comprises 16 or more vias that penetrate the board.

4. The sensor according to claim 1, comprising a total of four baluns along the current loop.

5. The sensor according to claim 1, wherein a set of pickup circuits for the current loop is electrically isolated from a set of pickup circuits for the voltage ring.

6. The sensor according to claim 5, wherein the insulating feature between the set of pickup circuits for the current loop and the set of pickup circuits for the voltage ring includes a ground via that penetrates the board.

7. The sensor according to claim 1, wherein the internal ring is an electric field pickup surface and the external ring is grounded.

8. A second aperture penetrating the aforementioned board, The second current loop around the second aperture, and The second voltage ring located on the inner circumference of the second current loop The sensor according to claim 1, further comprising:

9. The protective ring around the current loop, and Second protective ring around the second current loop The sensor according to claim 8, further comprising:

10. The sensor according to claim 9, wherein the position of the second via of the second protective ring is rotated relative to the position of the first via of the protective ring.

11. It is a sensor, A board that is designed so that the aperture penetrates through it. A current loop around the aperture, A pair of beers inside, A pair of beers on the outside, A plurality of conductive traces, wherein each conductive trace connects a via from an inner pair of vias to a via from an outer pair of vias, and the plurality of conductive traces are alternately arranged on the top surface and the bottom surface of the board. A current loop equipped with A voltage ring located on the inner circumference of the current loop, The inner ring, An insulating ring around the aforementioned internal ring, The outer ring around the aforementioned insulating ring and A voltage ring equipped with A protective ring around the current loop, and One or more baluns in each of the notches in the protective ring, one or more baluns electrically connected to the current loop, A sensor equipped with this feature.

12. The sensor according to claim 11, wherein the number of the inner pair of vias is equal to the number of the outer pair of vias.

13. The sensor according to claim 11, wherein a set of pickup circuits for the current loop is electrically isolated from a set of pickup circuits for the voltage ring.

14. It is a processing tool, power supply, An impedance matching network connected to the aforementioned power supply, A cathode, wherein the power supply is configured to supply power to the cathode via the impedance matching network. A processing module that is communicably connected to the aforementioned power supply and the aforementioned impedance matching network, A first sensor provided upstream of the impedance matching network, and a second sensor provided downstream of the impedance matching network, wherein the first sensor and the second sensor are each, A board formed so that an aperture penetrates, A current loop passing through the board so as to wrap around the aperture, A voltage ring located around the aperture and on the inner circumference of the current loop, Internal ring, The insulating ring around the aforementioned internal ring, and Outer ring around the aforementioned insulating ring A voltage ring equipped with A first sensor and a second sensor, A protective ring around the current loop, and One or more baluns in each of the notches in the protective ring, one or more baluns electrically connected to the current loop, A processing tool equipped with these features.

15. The processing tool according to claim 14, wherein the current loop comprises a first winding and a second winding.

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