Ion implantation system and monitoring circuit for use therewith

Abstract

A monitoring circuit including a pickup circuit to monitor a voltage applied to a chamber of a linear accelerator is disclosed, and more specifically, an ion implantation system and a monitoring circuit for use therewith are disclosed. The monitoring circuit is electrically isolated from the linear accelerator and is also electrically isolated from a controller that receives input from the circuit and controls the linear accelerator. In some embodiments, the monitoring circuit also includes an energy harvester to capture energy without any physical connection to the controller. For example, this can be achieved using light energy or electromagnetic energy. In some embodiments, the monitoring circuit includes an analog / digital converter to convert a signal received from the pickup circuit into a digital value. In other embodiments, the monitoring circuit transmits an analog voltage to the controller. The output from the monitoring circuit may include the amplitude and phase of the voltage being applied to the corresponding chamber.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to systems for detecting voltage and / or current of a linear accelerator resonator element and transmitting the voltage or current to a controller, and more particularly to an ion implantation system and monitoring circuit for use therewith. Background Art

[0002] The fabrication of semiconductor devices involves multiple discrete and complex processes. In some of these processes, ions are accelerated toward a workpiece. These ions can be accelerated in several ways. For example, electric fields are often used to attract and accelerate positively charged ions.

[0003] In some embodiments, a linear accelerator (LINAC) may be used to accelerate the ions. In some embodiments, the LINAC includes multiple radio frequency (RF) chambers, each of which is used to further accelerate the ions passing therethrough. The LINAC may operate optimally when each of the RF chambers is powered at its respective resonant frequency.

[0004] Although linear accelerators are used to accelerate ions, there are challenges associated with the use of linear accelerators. For example, in some embodiments, the chamber may be powered at voltages of millions of volts. In addition, glitches or other anomalies may occur in the linear accelerator, which can affect the quality of the beam.

[0005] Thus, it can be difficult to monitor the voltage being applied to each chamber of a linear accelerator due to the potential for both ground loops and false signals.

[0006] Therefore, it would be advantageous if there was a system that could reliably measure voltages associated with a linear accelerator. It would be beneficial if the system was electrically isolated from the linear accelerator and electrically isolated from the controller. Summary of the invention

[0007] A monitoring circuit is disclosed that includes a pickup loop to monitor a voltage applied to a chamber of a linear accelerator. The monitoring circuit is electrically isolated from the resonator chamber and is also electrically isolated from a controller that receives input from the circuit and controls the linear accelerator. In some embodiments, the monitoring circuit also includes an energy harvester to capture energy without any physical connection to the controller. For example, this can be achieved using light energy or electromagnetic energy. In some embodiments, the monitoring circuit includes an analog / digital converter to convert a signal received from the pickup loop into a digital value. In other embodiments, the monitoring circuit passes an analog voltage to the controller. The output from the monitoring circuit may include the amplitude and phase of the voltage being applied to the corresponding chamber.

[0008] According to one embodiment, an ion implantation system is disclosed. The ion implantation system includes: an ion source for generating ions; a linear accelerator for accelerating the ions toward a workpiece, wherein the linear accelerator includes one or more chambers; a controller; and a monitoring circuit, including a pickup loop disposed near one of the one or more chambers, and a transceiver for transmitting and receiving information from the controller; wherein the monitoring circuit is electrically isolated from the controller and the linear accelerator. In some embodiments, the ion implantation system also includes: a radio frequency generator in communication with the controller; and an excitation coil and a resonator coil disposed in each chamber, wherein the radio frequency generator supplies an excitation voltage to the excitation coil. In some embodiments, the pickup loop receives an induction signal from the one of the one or more chambers, and information about the induction signal is transmitted from the monitoring circuit to the controller without a physical electrical connection. In some embodiments, the controller uses the information from the monitoring circuit to control the radio frequency generator. In some embodiments, the information includes the amplitude and phase of the induction signal. In some embodiments, the ion implantation system further comprises a tuner blade disposed in each chamber, wherein the controller controls the position of the tuner blade in each of the one or more chambers based on information from the monitoring circuit. In some embodiments, the monitoring circuit detects false signals on the pickup loop. In some embodiments, the monitoring circuit comprises an energy harvesting circuit, wherein the energy harvesting circuit is used to provide power to the monitoring circuit without a physical electrical connection. In some embodiments, the controller comprises an energy source, wherein energy from the energy source is wirelessly transmitted to the energy harvesting circuit. In some embodiments, the transceiver comprises a fiber optic transceiver. In some embodiments, the monitoring circuit and the controller are disposed on a printed circuit board having separate ground and power planes.

[0009] According to another embodiment, a monitoring circuit for use with an ion implantation system is disclosed. The monitoring circuit includes: an energy harvesting circuit for providing power; a pickup loop on which a voltage or current is sensed; an amplifier for amplifying a signal from the pickup loop; an analog-to-digital converter (ADC) for converting the signal into a digital representation; and a transceiver for transmitting the digital representation to a controller; wherein the monitoring circuit is electrically isolated from the controller. In certain embodiments, the energy harvesting circuit includes a transducer, a conversion circuit, and an energy storage circuit. In some embodiments, the transducer includes a photoelectric sensor. In some embodiments, the transceiver includes a fiber optic transceiver.

[0010] According to another embodiment, a monitoring circuit for use with an ion implantation system is disclosed. The monitoring circuit includes: an energy harvesting circuit for providing power; a pickup loop on which a voltage or current is induced; an amplifier for amplifying a signal from the pickup loop; an amplitude detection circuit; a phase detection circuit; an analog multiplexer that takes as inputs an output of the amplitude detection circuit and an output of the phase detection circuit; and a transceiver for transmitting the output from the analog multiplexer to a controller; wherein the monitoring circuit is electrically isolated from the controller. In some embodiments, the controller uses the transceiver to transmit a master clock signal to the monitoring circuit, and the master clock signal is used by the phase detection circuit. In some embodiments, the controller uses the transceiver to transmit a control signal to the monitoring circuit, and the control signal is used by the analog multiplexer to select one of the inputs. In some embodiments, the transceiver includes a fiber optic transceiver. In some embodiments, the energy harvesting circuit includes a transducer, a conversion circuit, and an energy storage circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a better understanding of the present disclosure, reference is made to the accompanying drawings which are incorporated herein by reference, and wherein:

[0012] Figure 1 A block diagram of an ion implantation system utilizing a linear accelerator (or LINAC) is shown according to one embodiment.

[0013] Figure 2 A monitoring circuit according to one embodiment is shown.

[0014] Figure 3 A monitoring circuit according to a second embodiment is shown.

[0015] Figure 4 A block diagram of an ion implantation system according to another embodiment is shown. DETAILED DESCRIPTION

[0016] As described above, a linear accelerator may be used to accelerate ions toward a workpiece. Figure 1An ion implantation system 1 is shown. The ion implantation system 1 includes an ion source 10. The ion source 10 may be any suitable ion source, such as, but not limited to, an indirectly heated cathode (IHC) source, a Bernas source, a capacitively coupled plasma source, an inductively coupled plasma source, or any other suitable device. The ion source 10 has an orifice through which ions may be extracted from the ion source 10. The ions may be extracted from the ion source 10 by applying a negative voltage to one or more electrodes 20 disposed outside the ion source 10 near the extraction orifice. The electrodes 20 may be pulsed so that ions leave at a particular time. The group of ions that leave may be referred to as a bunch.

[0017] The ions may then enter a mass analyzer 30, which may be a magnet that allows ions with a specific mass to charge ratio to pass through. This mass analyzer 30 is used to separate only the desired ions. The desired ions then enter a linear accelerator 40.

[0018] The linear accelerator 40 includes one or more chambers 41. In some embodiments, there may be between one and sixteen chambers 41 in the linear accelerator 40. Each chamber 41 includes a resonator coil 42, which can be powered by an electromagnetic field formed by an excitation coil 45. The excitation coil 45 is disposed in the chamber 41 together with the corresponding resonator coil 42. The excitation coil 45 is powered by an excitation voltage, which can be a radio frequency signal. The corresponding radio frequency generator 44 can supply the excitation voltage. In other words, the excitation voltage applied to each excitation coil 45 can be independent of the excitation voltage supplied to any other excitation coil 45. Each excitation voltage is preferably modulated to be at the resonant frequency of its corresponding chamber 41. The controller 200 in communication with the radio frequency generator 44 can determine and change the magnitude and phase of the excitation voltage. By arranging the resonator coil 42 in the chamber 41, the magnitude of the excitation voltage can be increased or the phase of the excitation voltage can be shifted while keeping the amplitude of the excitation voltage the same.

[0019] Within each chamber 41 there may be a corresponding tuner blade 46. The tuner blade 46 may be in communication with an actuator to modify the position of the tuner blade 46 within the chamber 41. The position of the tuner blade 46 may affect the resonant frequency of the chamber 41. The actuator may be controlled by the controller 200.

[0020] When an excitation voltage is applied to the excitation coil 45, a voltage is induced on the resonator coil 42. As a result, the resonator coil 42 in each chamber 41 is driven by a sinusoidal voltage. Each resonator coil 42 may be in electrical communication with a corresponding accelerator electrode 43. Ions pass through an aperture in each accelerator electrode 43.

[0021] The time that the beam enters a particular accelerator electrode 43 is timed so that the potential of the accelerator electrode 43 is negative when the beam approaches, but switches to positive when the beam passes through the accelerator electrode 43. In this way, the beam is accelerated when it enters the accelerator electrode 43, and the beam is repelled when it leaves. This causes the beam to accelerate. This process is repeated for each accelerator electrode 43 in the linear accelerator 40. Each accelerator electrode increases the acceleration of the ions and can be measured.

[0022] As the beam leaves the linear accelerator 40 , the beam is implanted into the workpiece 50 .

[0023] Of course, the ion implantation system 1 may include other components, such as an electrostatic scanner for forming a ribbon beam, a quadrupole element, additional electrodes for accelerating or decelerating the beam, and other elements.

[0024] In some embodiments, the ion implantation system 1 further includes a monitoring circuit 100 and a controller 200. In some embodiments, each chamber 41 has a separate monitoring circuit 100. Figure 1 Only a single monitoring circuit 100 and controller 200 are shown. However, these components may be repeated in each chamber 41. For example, each chamber 41 may be associated with a respective RF generator 44, monitoring circuit 100, and controller 200.

[0025] The monitoring circuit 100 includes a pickup loop 101 that is disposed near or within one of the chambers 41. The electromagnetic field near or within the chamber 41 induces a sinusoidal voltage on the pickup loop 101. The monitoring circuit 100 receives this sinusoidal voltage from the pickup loop 101 and provides some signal processing. The monitoring circuit 100 transmits these processed signals to the controller 200 without any electrical connection, as described below. The pickup loop 101 may be just a loop-shaped wiring.

[0026] The controller 200 includes a processing unit 220 and an associated storage device 225. The storage device 225 contains instructions that, when executed by the processing unit 220, enable the controller 200 to perform the functions described herein. The processing unit 220 may be a microprocessor, a signal processor, a custom field programmable gate array (FPGA), or another suitable unit. The storage device 225 may be a non-volatile memory, such as a flash read only memory (FLASH read only memory, FLASH ROM), an electrically erasable ROM, or other suitable device. In other embodiments, the storage device 225 may be a volatile memory, such as a random access memory (RAM) or a dynamic random access memory (DRAM).

[0027] A global controller 90 is also shown. The global controller 90 may be in communication with a plurality of monitoring circuits 100 and the controller 200. The global controller 90 may form a master clock used by the rest of the ion implantation system 1. The global controller 90 may include a processing unit 91 and a storage device 92. The processing unit 91 may be a microprocessor, a signal processor, a custom field programmable gate array (FPGA), or another suitable unit. This storage device 92 may be a non-volatile memory, such as a flash ROM, an electrically erasable ROM, or other suitable device. In other embodiments, the storage device 92 may be a volatile memory, such as a RAM or DRAM. The storage device 92 contains instructions that enable the global controller 90 to perform the tasks described herein.

[0028] Figure 2 A first embodiment of a monitoring circuit 100a and a controller 200a is shown.

[0029] The monitoring circuit 100a includes a preamplifier 110. The preamplifier 110 is used to amplify the sinusoidal signal sensed on the pickup loop 101. For example, the output of the preamplifier 110 may be a voltage between 0 volts and 10 volts or between +5 volts and -5 volts. In other embodiments, the output of the preamplifier 110 may have a different voltage range. In other embodiments, the output of the pickup loop 101 may be a current.

[0030] In some embodiments, the output of the preamplifier 110 is used as an input to a glitch detection circuit 120. The glitch detection circuit 120 is used to determine when a glitch occurs on the signal sensed on the pickup loop 101. In some embodiments, this information can be transmitted directly to the global controller 90 via an optical fiber connection (not shown) to maintain electrical isolation. If an event occurs, the global controller 90 can make a decision about the appropriate action. In other embodiments, the information from the glitch detection circuit 120 can be transmitted to the controller 200a. In some embodiments, the controller 200a can adjust the resonant frequency as desired. This adjustment can be made by actuating the tuner blade 46.

[0031] The output of the preamplifier 110 may also be used as an input to an analog-to-digital converter (ADC) 130. The ADC 130 samples the analog voltage received from the preamplifier 110 and generates a digital representation of the analog voltage. In some embodiments, the digital representation may be an 8-bit, 12-bit, or 16-bit representation. The ADC 130 may sample the analog voltage periodically or at regular intervals.

[0032] To periodically sample the analog voltage, the monitoring circuit 100a also includes a clock generation and control circuit 140. The clock generation and control circuit 140 is responsible for forming a clock signal used in the monitoring circuit 100a. In one embodiment, the clock generation and control circuit 140 may be connected to a crystal that oscillates at a fixed frequency. This fixed frequency can be used to generate a clock signal used by the ADC 130. In another embodiment, the controller 200a may supply a control signal 181 to the monitoring circuit 100a. One of these control signals may be a master clock signal. The clock generation and control circuit 140 may receive this master clock signal as an input and use this master clock signal to generate a clock signal used by the ADC 130. The specific implementation for generating a clock signal for the ADC 130 is not limited by the present disclosure.

[0033] The output from ADC 130 may enter data conditioning circuit 170. Data conditioning circuit 170 may be used to condition the digital representation before transmitting it to controller 200a. Data conditioning circuit 170 may be a logarithmic amplifier that may be used to automatically adjust the gain, or simply a preamplifier. In other embodiments, the output from ADC 130 may enter transceiver 150 directly.

[0034] The output of the data conditioning circuit 170 enters the transceiver 150 where the data 182 is transmitted to the controller 200a. The transceiver 150 communicates with the controller 200a without using any physical electrical connections.

[0035] In one embodiment, the transceiver 150 is a fiber optic transceiver. In this embodiment, the transceiver 150 can condition and encode the data 182 into light pulses. These light pulses travel through the fiber 180 to the controller 200a.

[0036] The controller 200a includes a corresponding transceiver 250 that interfaces with the transceiver 150. In the case of fiber optics, a glass fiber 180 is used to connect the two transceivers.

[0037] In addition to receiving data 182 from monitoring circuit 100a, controller 200a can also send control signals 181 to monitoring circuit 100a. As described above, clock generation and control circuit 140 can use control signals 181 to generate the signals needed to sample the incoming signals.

[0038] Therefore, the monitoring circuit 100a and the controller 200a are able to transmit data 182 and control signals 181 between each other without any physical electrical connection. In this way, there is no common ground and no potential ground loop.

[0039] To further isolate the monitoring circuit 100a from the controller 200a, the monitoring circuit 100a further includes an energy harvesting circuit 160. The energy harvesting circuit 160 is used to supply power to the monitoring circuit 100a. The energy harvesting circuit 160 includes a transducer 161, a conversion circuit 162, and an energy storage circuit 163. The transducer 161 receives input and converts the input into electrical energy. In one embodiment, the transducer 161 may be a photoelectric sensor that receives light and converts the light into electrical energy. In another embodiment, the transducer 161 may be a thermoelectric transducer that converts heat into electrical energy. In another embodiment, the transducer 161 may be a piezoelectric device that converts vibration or movement into electrical energy. In another embodiment, the transducer 161 may be an RF transducer that converts RF energy into electrical energy. In yet another embodiment, the transducer 161 may be an inductive transducer that converts a magnetic field into electrical energy. Note that in each of these embodiments, the energy harvesting circuit 160 receives input energy without any physical electrical connection.

[0040] The conversion circuit 162 conditions the electrical energy generated by the transducer 161. The conversion circuit 162 is used to collect the energy output by the transducer 161 and convert the energy into a desired voltage, such as 3.3V, 5V, or some other voltage. The output from the conversion circuit 162 is then stored in the energy storage circuit 163. In some embodiments, the energy storage circuit 163 includes one or more capacitors and supporting circuits.

[0041] The output of the energy storage circuit 163 may be used to supply power to the remainder of the monitoring circuit 100a.

[0042] In some embodiments, the controller 200a cooperates with the monitoring circuit 100a to provide energy to the energy harvesting circuit 160. For example, the controller 200a may include an energy source 260. In one embodiment, this energy source 260 includes a light source, such as a light-emitting diode (LED) or a laser. This light source can be directed toward a photoelectric sensor disposed on the monitoring circuit 100a to maximize the energy harvesting efficiency. In another embodiment, the energy source 260 can be a coil driven by an alternating current to form an electric field, which can be received by an inductive transducer. In another embodiment, the energy source 260 can be an RF generator that emits RF energy, which is captured by an RF transducer. Of course, other energy sources can also be used.

[0043] In some embodiments, the controller 200a and the monitoring circuit 100a may be disposed on physically different printed circuit boards. In another embodiment, the controller 200a and the monitoring circuit 100a may be disposed on a single printed circuit board in which the power plane and the ground plane are physically separated. For example, the ground layer may include two separate ground planes that are physically separated from each other.

[0044] In operation, the controller 200a may activate the energy source 260. This provides energy to the energy harvesting circuit 160. After a while, enough power may be stored in the energy storage circuit 163 so that the remaining components on the monitoring circuit 100a can receive power. Therefore, at this point, the monitoring circuit 100a is fully operational. It should also be noted that there is no physical electrical connection between the controller 200a and the monitoring circuit 100a. Once powered on, the monitoring circuit 100a may receive a sinusoidal signal from the pickup loop 101. In some embodiments, the controller 200a uses the transceiver 250 to provide control signals 181 to the monitoring circuit 100a. These control signals 181 from the controller 200a are used to determine the sampling rate of the ADC 130. The digital representation of the output from the ADC 130 is then transmitted to the controller 200a using the transceiver 150. The transceiver 250 receives these values ​​and transmits them to the processing unit 220. The information received by the processing unit 220 can be used to maintain resonance and control the RF generator 44 accordingly. Processing unit 220 may use this information in a number of different ways, as described below.

[0045] Figure 3 Another embodiment of the monitoring circuit 100b and the controller 200b is shown. In this embodiment, the monitoring circuit 100b does not include an analog / digital converter. Instead, the monitoring circuit 100b transmits an analog signal to the controller 200b.

[0046] Therefore, as regards Figure 2As described above, the sinusoidal voltage induced on the pickup loop 101 is the input to the preamplifier 310. The output of the preamplifier 310 can be one of several inputs to the analog multiplexer 360.

[0047] In some embodiments, the sinusoidal voltage sensed on the pickup loop 101 may also be an input to the glitch detection circuit 320. Figure 2 Same as described.

[0048] The sinusoidal voltage induced on the pickup loop 101 can also be used to perform other functions. For example, in one embodiment, the amplitude of the sinusoidal signal induced on the pickup loop 101 is determined using the amplitude detection circuit 330. The output of the amplitude detection circuit 330 can be an analog voltage representing the amplitude of the sinusoidal signal. The amplitude detection circuit 330 can be an envelope detector or another type of circuit. The output of the amplitude detection circuit 330 can be another input to the analog multiplexer 360.

[0049] Additionally, the sinusoidal voltage induced on the pickup loop 101 can be used as an input to the phase detection circuit 340. The phase detection circuit 340 compares the phase of the incoming sinusoidal signal to a fixed reference and outputs a voltage representing the phase difference between the two signals. In some embodiments, this fixed reference can be the master clock signal 383 received from the controller 200b. The output of the phase detection circuit 340 can be another input to the analog multiplexer 360.

[0050] Analog multiplexer 360 may have multiple inputs. Figure 3 Three inputs are shown, but the number of inputs is not limited by the present disclosure. In addition, the monitoring circuit 100b may not include all the circuits described above (ie, the amplitude detection circuit 330 and the phase detection circuit 340).

[0051] One or more control signals 381 from controller 200b may be used to select one of the multiple inputs to be passed to the output of analog multiplexer 360. This output from analog multiplexer 360 is then transmitted via transceiver 350 to controller 200b.

[0052] The transceiver 350 transmits the output from the analog multiplexer 360 as data 382 and the data 382 is received by the transceiver 390. As described above, the transceiver may be a fiber optic transceiver utilizing the fiber 380. An analog / digital converter (ADC) 370 disposed on the controller 200b samples the received data 382. The output of the ADC 370 may then be provided to the processing unit 220.

[0053] Figure 3 The energy harvesting circuit 160 of the monitoring circuit 100b is similar to the Figure 2 The energy harvesting circuit 160 of the controller 200b is the same as that described above. Figure 2 The contents described are the same.

[0054] As described above, in both embodiments, the monitoring circuit 100 is configured to supply data to the controller 200 regarding the voltage being applied to the chamber 41 of the linear accelerator 40. The controller 200 can use this information in several ways.

[0055] First, the processing unit 220 may vary the frequency of the excitation voltage applied to the chamber 41 in an attempt to induce a resonant state. In other words, when the frequency of the excitation voltage applied to the excitation coil 45 matches the natural resonant frequency of the resonator coil 42 and the natural resonant frequency of the chamber 41, the amplitude of the voltage induced by the pickup circuit 101 will reach its maximum value. Therefore, the processing unit 220 may select a specific frequency for the excitation voltage, instruct the RF generator 44 to apply the excitation voltage to the excitation coil 45, and obtain feedback from the monitoring circuit 100 indicating the relative amplitude of the induced voltage.

[0056] exist Figure 1 In the monitoring circuit 100a of FIG. 1 , the controller 200a may obtain multiple samples from the ADC 130 to determine the peak amplitude. Figure 3 In the monitoring circuit 100b, the controller 200b can control the analog multiplexer 360 to select the output of the amplitude detection circuit 330. The analog voltage received from the amplitude detection circuit 330 represents the amplitude of the sensing signal. Then, the processing unit 220 samples the analog / digital converter (ADC) 370 once to determine the amplitude of the sensing voltage.

[0057] The controller 200 may then modify the frequency of the excitation voltage by instructing the RF generator 44 to modify the output frequency of the excitation voltage. The controller 200 may then obtain an indication of the amplitude of the induced signal, as described above. The controller 200 may repeat this process until a maximum induced voltage has been achieved.

[0058] By varying the frequency of the excitation voltage applied to the excitation coil 45 , the processing unit 220 may be able to optimize the performance of the linear accelerator 40 by ensuring that each chamber 41 operates at its resonant frequency.

[0059] In some embodiments, it may be desirable for all chambers 41 to have the same resonant frequency. Therefore, in this embodiment, the controller 200 may repeat the sequence described above, but instead of changing the frequency applied by the RF generator 44, the controller 200 changes the position of the tuner blade 46 in the chamber 41 until a predetermined resonant frequency is obtained.

[0060] In addition, the controller 200 may also control the phase of the voltage being generated by the resonator coil 42. As described above, the time at which the beam enters a particular accelerator electrode 43 is timed so that the potential of the accelerator electrode 43 is negative when the beam approaches, but switches to positive when the beam passes through the accelerator electrode 43. In this way, the beam is accelerated when entering the accelerator electrode 43, and the beam is repelled when leaving. To maximize this effect, the phase of each accelerator electrode 43 is appropriately correlated.

[0061] exist Figure 1 In the monitoring circuit 100a of FIG. 1 , the controller 200a may obtain multiple samples from the ADC 130 to determine the phase of the sensed voltage. For example, the signal reconstructed from the multiple samples from the ADC 130 may be compared with the master clock signal to determine the phase. Figure 3 In the monitoring circuit 100b, the controller 200b can control the analog multiplexer 360 to select the output of the phase detection circuit 340. The analog voltage received from the phase detection circuit 340 represents the phase of the sensing signal. Then, the processing unit 220 samples the analog / digital converter (ADC) 370 once to determine the phase of the sensing voltage.

[0062] The global controller 90 may instruct each controller 200 of the desired phase. The controller 200 then attempts to achieve this phase. For example, the controller 200 may utilize a phase lock loop that temporarily increases the frequency if the phase is lagging and temporarily decreases the frequency if the phase is leading. In another embodiment, the controller 200 may modify the position of the tuner blade 46 in the chamber 41 to adjust the phase of the induced voltage.

[0063] Therefore, the processing unit 220 passes Figure 2 The monitoring circuit 100a monitors the digital representation of the induced voltage and determines the amplitude and phase of the induced voltage. This can be done by sampling the induced voltage at a sampling frequency that is at least twice the frequency of the excitation voltage. Based on the processing unit 220 determining the amplitude and phase, the processing unit 220 can optimize the frequency and phase of the excitation voltage.

[0064] about Figure 3 , the monitoring circuit 100b includes circuits that provide analog voltages that represent the voltage and phase of the induced signal. The processing unit 220 can then sample these analog voltages using the ADC 370. Based on the amplitude and phase determined by the processing unit 220, the processing unit 220 can optimize the frequency and phase of the excitation voltage that keeps the resonator coil resonant.

[0065] The above disclosure describes normal operation. However, other factors may also be considered. For example, in the event of a glitch, the glitch detection circuit 120 provides information to the global controller 90. The global controller 90 may instruct the controller 200 to recalibrate the chamber 41 or take some other action.

[0066] Additionally, temperature changes and vibrations may affect the natural resonant frequency of the chamber 41. The controller 200 may continuously monitor the amplitude of the sensed signal. A decrease in the maximum amplitude of the sensed signal may indicate that the natural resonant frequency has drifted. The controller 200 may initiate corrective action. For example, in one embodiment, the controller 200 may move the tuner blade 46 in the chamber 41 to regain the resonant frequency. The controller 200 may report any changes in the resonant frequency to the global controller 90. The global controller 90 may then instruct the controller 200 to take some corrective action.

[0067] Although the above disclosure describes the use of the monitoring circuit with the linear accelerator 40, the present disclosure is not limited to this embodiment. The present monitoring circuit can be used in any environment where electrical isolation from both the system being monitored and the controller is required. For example, the monitoring circuit described herein can be used to measure current in an ion implantation system.

[0068] For example, Figure 4 An ion implantation system 401 is shown that includes a current measuring device (e.g., a Faraday device). The ion implantation system 401 includes an ion source 410. The ion source 410 can be any suitable ion source, such as, but not limited to, an indirect heated cathode (IHC) source, a Berners source, a capacitively coupled plasma source, an inductively coupled plasma source, or any other suitable device. The ion source 410 has an orifice through which ions can be extracted from the ion source 410. The ions can be extracted from the ion source 410 by applying a negative voltage to one or more electrodes 420 disposed outside the ion source 410 near the extraction orifice.

[0069] The ions may then enter a mass analyzer 430, which may be a magnet that allows ions with a specific mass-to-charge ratio to pass through. This mass analyzer 430 is used to separate only the desired ions. The desired ions then enter one or more acceleration / deceleration stages 440. The ions leaving the acceleration / deceleration stages 440 may then be transformed into a ribbon ion beam 451 by using an electrostatic scanner 450. The ribbon ion beam 451 is then directed toward a workpiece 460. To measure the actual beam current, a current measuring device 470, such as a Faraday cup, may be disposed near the workpiece 460. The current measuring device 470 may be in communication with an actuator to move in and out of the path of the beam. To measure the current, the workpiece 460 is moved away so that the ribbon ion beam 451 strikes the Faraday cup.

[0070] The output of the Faraday cup replaces the pickup loop 101 in the monitoring circuit 100. The remainder of the monitoring circuit is exactly as described above with respect to 100. However, in this case, instead of measuring voltage, current is monitored by the monitoring circuit 100. However, similar to the other embodiments, the monitoring circuit 100 is electrically isolated from both the ion implantation system 401 and the controller 200.

[0071] The present system has many advantages. The ability to monitor parameters in a high voltage system is very advantageous. However, there are often problems with monitoring high voltage systems using conventional measurement devices. Specifically, the high voltage system may have a different ground reference than the controller. In addition, these high voltage systems may form arcs or false signals, which may affect the ground plane of the system. If a typical controller is connected to the same ground plane, the controller may be damaged by these arcs or false signals. The present system overcomes these disadvantages by introducing a monitoring circuit that is electrically isolated from both the system being monitored and the controller. In addition, because the monitoring circuit is electrically isolated, the accuracy of voltage monitoring is improved.

[0072] The scope of the present disclosure is not limited by the specific embodiments described herein. In fact, by reading the above description and drawings, various other embodiments of the present invention and various modifications to the present invention in addition to the embodiments and modifications described herein will also be apparent to those of ordinary skill in the art. Therefore, these other embodiments and modifications are intended to be within the scope of the present disclosure. In addition, although the present disclosure has been set forth in the context of a specific embodiment in a specific environment for a specific purpose, a person of ordinary skill in the art will recognize that the utility of the present disclosure is not limited thereto and the present disclosure can be beneficially implemented in any number of environments for any number of purposes. Therefore, the above-mentioned claims should be understood in view of the full scope and spirit of the present disclosure described herein.

Claims

1. An ion implantation system comprising: an ion source for generating ions; a linear accelerator for accelerating the ions toward a workpiece, wherein the linear accelerator comprises one or more chambers, an excitation coil and a resonator coil being disposed in each of the one or more chambers of the chambers, the resonator coil being powered by an electromagnetic field formed by the excitation coil, and the excitation coil being powered by an excitation voltage supplied by a radio frequency generator; Controller; as well as Monitoring circuit, including: a pickup circuit disposed proximate to one of the one or more chambers to receive an induction signal from the one of the one or more chambers, wherein the induction signal is induced by an electromagnetic field within or near one or more of the chambers; A transceiver is used to transmit and receive information from the controller; wherein the monitoring circuit is electrically isolated from the controller and the linear accelerator.

2. The ion implantation system of claim 1, wherein the RF generator is in communication with the controller.

3. The ion implantation system of claim 2, wherein information about the sense signal is transmitted from the monitoring circuit to the controller without a physical electrical connection.

4. The ion implantation system of claim 3, wherein said controller uses said information from said monitoring circuit to control said RF generator.

5. The ion implantation system of claim 4, wherein the information comprises an amplitude and a phase of the sensing signal.

6. The ion implantation system of claim 3 , further comprising a tuner vane disposed in each of the one or more chambers, wherein the controller controls a position of the tuner vane in each of the one or more chambers based on information from the monitoring circuit.

7. The ion implantation system of claim 1, wherein the monitoring circuit comprises an energy harvesting circuit for providing power to the monitoring circuit without a physical electrical connection.

8. The ion implantation system of claim 7, wherein the controller comprises an energy source, wherein energy from the energy source is wirelessly transmitted to the energy harvesting circuit.

9. The ion implantation system of claim 1 wherein said monitoring circuit and said controller are disposed on a printed circuit board having separate ground and power planes.

10. The ion implantation system of any one of claims 1-9, wherein the monitoring circuit further comprises: Energy harvesting circuit for providing power; an amplifier, used to amplify the signal from the pickup circuit; as well as an analog-to-digital converter (ADC) for converting the signal into a digital representation; Wherein the transceiver transmits the digital representation to the controller.

11. The ion implantation system of claim 10, wherein the energy harvesting circuit comprises a transducer, a conversion circuit, and an energy storage circuit.

12. The ion implantation system of claim 11, wherein the transducer comprises a photosensor.

13. The ion implantation system of any one of claims 1 to 9, wherein the monitoring circuit further comprises: Energy harvesting circuit for providing power; an amplifier, used to amplify the signal from the pickup circuit; Amplitude detection circuit; Phase detection circuit; as well as an analog multiplexer having as input the output of the amplitude detection circuit and the output of the phase detection circuit; The transceiver transmits the output from the analog multiplexer to the controller.

14. The ion implantation system of claim 13, wherein the controller transmits a master clock signal to the monitoring circuit using the transceiver, and the master clock signal is used by the phase detection circuit.

15. The ion implantation system of claim 13, wherein the controller transmits a control signal to the monitoring circuit using the transceiver, and the control signal is used by the analog multiplexer to select one of the inputs.

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