Measurement of capacitance or impedance of load in high voltage dc power supply

Abstract

The invention provides a power supply comprising a current sensor for measuring an oscillating current through a load connected to the power supply; the voltage sensor is used for measuring oscillation voltage on the load; and the source conductor is used for transmitting the sine voltage generated by the sine wave oscillator. The microcontroller is connected with the current sensor, the voltage sensor and the source conductor. The microcontroller calculates the impedance or capacitance of the load using digital data generated by the three sensors.

Description

Technical Field

[0001] This disclosure generally relates to power supplies suitable for generating direct current (DC) high voltage, which are capable of monitoring the impedance or capacitance of a load connected to the power supply. More specifically, this disclosure relates to such power supplies suitable for use with electrostatic chucks. Background Technology

[0002] In the manufacturing process of semiconductors and LCD panels, vacuum chucks and mechanical chucks have traditionally been used to hold substrates for processing. However, due to the effects of adsorption and deformation, as well as increased reliability requirements, electrostatic chucks are now widely used in semiconductor equipment to overcome these limitations.

[0003] An electrostatic chuck (“e-chuck”) consists of a clamping plate with surface electrodes. A high-voltage bias is applied to the surface electrodes to establish an electrostatic force between the clamping plate and the wafer. There are two types of electrostatic chucks: Coulomb and Johnsen-Rahbek (“JR”) types. They differ in their dielectric properties, and therefore in how the clamping force is generated. A Coulomb chuck functions similarly to a conventional dielectric capacitor. The JR type has a large but finite resistance, so when the surfaces are in close contact and a voltage is applied, current flows through it and the substrate. Charge accumulates at the interface between the substrate and the dielectric, thus providing the clamping force.

[0004] Furthermore, different configurations of the electrodes (or poles) on the chuck can be used to obtain different characteristics. Depending on the application, single-pole, bipolar, and multi-pole chucks (including 6-phase six-pole types) are available.

[0005] The power supply is known to be suitable for all types of electronic chucks. The power supply has the following characteristics:

[0006] High-voltage bipolar output (positive / negative);

[0007] Output polarity reversal function facilitates wafer clamping / unclamping;

[0008] The wafer condition can be detected by capacitance measurement (coulomb chuck) or current measurement (JR chuck); and / or

[0009] Analog and digital interfaces facilitate integration into various systems.

[0010] For example, Figure 1 illustrates a known power supply suitable for a coulomb chuck. In this example, the power supply is bipolar, comprising two terminals 26a and 26b. A load 10 (e.g., a coulomb-type electrostatic chuck) is shown connected between the two terminals 26a and 26b. In use, each of generators 12a and 12b generates a high-voltage direct current (DC) applied to the load 10.

[0011] The power supply shown in Figure 1 includes a sinusoidal oscillator 16. In use, the sinusoidal oscillator 16 generates a sinusoidal voltage at a predetermined frequency. The sinusoidal oscillator 16 is connected to the first lead of capacitor 18, and the second lead of capacitor 18 is connected to terminal 26a. The sinusoidal voltage applied to the first lead of capacitor 18 causes an oscillating current to flow out from ground. A first portion of this oscillating current can flow back to ground via blocking inductor 14a and generator 12a. A second portion of this oscillating current can flow back to ground via load 10, capacitor 22, and current-to-voltage converter 20. A third portion of this oscillating current can flow back to ground via load 10, blocking inductor 14b, and generator 12b.

[0012] The first part of the oscillating current is ideally negligible compared to the second part. Conversely, the second part of the oscillating current is almost equal to the alternating current (AC) flowing through the load. Similarly, the third part of the oscillating current is also ideally negligible compared to the second part.

[0013] Because the load 10, the blocking inductor 14a, and the coupling capacitor 18 are connected in parallel, an oscillating potential is generated on one lead of the load 10. Similarly, because the load 10, the blocking inductor 14b, and the coupling capacitor 22 are connected in parallel, an oscillating potential is generated on the other lead of the load 10.

[0014] The power supply shown in Figure 1 includes a first sensor for measuring the amplitude of a second portion of the oscillating current, which, as previously described, is approximately equal to the alternating current flowing through load 10. The first sensor includes a current-to-voltage converter 20, a full-wave rectifier, a low-pass filter, and one channel of an analog-to-digital converter ADC 24a. The first sensor cannot measure phase.

[0015] The power supply shown in Figure 1 includes a second sensor for measuring the amplitude of the sinusoidal voltage generated by the sinusoidal oscillator 16. The second sensor comprises a full-wave rectifier, a low-pass filter, and one channel of the ADC24a. The second sensor also cannot measure phase.

[0016] The power supply shown in Figure 1 cannot directly measure the voltage at terminal 26, so only the oscillating voltage generated by the first and second parts of the oscillating current flowing through capacitor 18 can be estimated.

[0017] The power supply shown in Figure 1 includes a microcontroller 24, which is programmed to estimate the capacitance of load 10 based on the digitized amplitude of the sinusoidal voltage, the amplitude of the alternating current flowing through load 10 (approximately the amplitude of the second part of the oscillating current), and the values ​​of capacitors 18 and 22. However, in some cases, the estimation of the capacitance of load 10 may not be accurate and / or precise enough.

[0018] The power supply shown in Figure 2 is bipolar. It has terminals A+ and B-, each connected to a load 10. It includes generators 12a and 12b and a monitor 34.

[0019] In this example, monitor 34 includes a sinusoidal oscillator 16a and a transformer 16b for injecting sinusoidal signals differentially through capacitors 18a and 18b. It is important to note that the circuit consisting of the sinusoidal oscillator 16a and transformer 16b can itself be considered as forming a sinusoidal oscillator: it generates two voltage signals at the leads of the two secondary coils of transformer 16b and a third voltage signal R (e.g., a reference signal) between two resistors connected in series with the two secondary coils. Blocking inductors 14a and 14b are used to increase the impedance of generators 12a and 12b at the frequency of the sinusoidal oscillator 16a.

[0020] Due to the combined action of the sine wave oscillator (composed of sine wave oscillator 16a and transformer 16b), capacitors 18a and 18b, and blocking inductors 14a and 14b, a first small portion of the alternating current (i.e., without a DC component) flows through the sine wave oscillators 16a / 16b (including through resistor 20a), capacitor 18a, blocking inductor 14a, generators 12a and 12b, blocking inductor 14b, capacitor 18b, and returns to the sine wave oscillators 16a / 16b. A second, larger portion of the alternating current flows through the sine wave oscillators 16a / 16b (including through resistor 20a), capacitor 18a, load 10, capacitor 18b, and returns to the sine wave oscillators 16a / 16b.

[0021] A floating sensor 21 is used to measure the alternating current flowing through load 10, which measures the voltage drop across resistor 20a. Sensor 21 includes a voltage follower, a differential amplifier, and filters (a bandpass filter connected to signal I*GI and circuit 32 and / or a bandpass filter connected to signal I*GI and circuit 33 via a multiplexer). This estimate can be used as the current flowing through load 10 when the first and third portions of the alternating current are sufficiently small compared to the second portion, such that the voltage drop across resistor 20a is primarily caused by the alternating current flowing through load 10 (i.e., the second portion of the alternating current).

[0022] Terminal A + The AC component of the voltage at point B is measured by a floating sensor 28, which includes a feedback capacitor, a voltage follower, a differential amplifier, and a filter (either connected to the signal V*GV and the bandpass filter of circuit 32 via a multiplexer, or connected to the signal V*GV and the bandpass filter of circuit 33 via a multiplexer). Assume the AC component of the voltage at point B is related to the voltage at point A. + The AC components of the terminal voltage are opposite.

[0023] The voltage V*GV, source S, and current I*GI signals are fed to demodulator 32, which provides an accurate method for calculating the phase of the current and voltage. In this example, demodulator 32 includes a pair of analog multipliers, each connected in series with a low-pass filter. Using the analog signals V*GV, I*GI, and S, demodulator 32 generates two analog signals: 1 / 2|V*GV|·|S|x COSφ(V*GV / S) and 1 / 2|I*GI|·|S|x COSφ(I*GI / S).

[0024] In this example, the monitor 34 also includes a rectifier 33, which generates one of three analog signals based on the state of the multiplexer after low-pass filtering: |V*GV|, |I*GI|, and |S|.

[0025] Microcontroller 24 digitizes the two analog signals generated by demodulator 32 and the three analog signals generated by rectifier 33. Known equations are programmed into microcontroller 24's firmware to calculate the capacitance / impedance of load 10 based on the digital data. However, in some cases, injecting sinusoidal signals differentially through capacitors 18a and 18b in a bipolar system may limit the power supply's flexibility and make it unsuitable for use with certain types of electronic chucks.

[0026] The power supply shown in Figure 3 represents one phase of a multi-pole system. It has terminal 26 connected to load 10. It includes generator 12 and monitor 34.

[0027] In this example, monitor 34 includes a sinusoidal oscillator 16 for adding a sinusoidal signal via a transformer 19 connected in series with the load. An RLC circuit 15 resonating at the sinusoidal signal frequency provides a very low impedance ground path for the injected alternating current.

[0028] Under the combined action of the sinusoidal oscillator 16, transformer 19, and RLC circuit 15, a small portion of alternating current (i.e., without DC component) first flows through the HV generator 12. The second, larger portion of alternating current is supplied from ground by the current-to-voltage converter 20, flows through the RLC circuit 15, the secondary coil of the voltage transformer 19, the load 10, and returns to ground.

[0029] A sensor comprising a current-to-voltage converter 20 and filters (a 90-degree hysteresis filter connected to signal I*GI and circuit 32 and / or a bandpass filter connected to signal I*GI and circuit 33) is used to estimate the alternating current flowing through load 10. This estimate can be used as the current flowing through load 10 when the first portion of the alternating current is sufficiently small compared to the second portion.

[0030] The AC component of the voltage at the terminals of load 10 is estimated by sensor 28, which is adapted to measure the voltage drop across the primary coil of voltage transformer 19. Voltage sensor 28 includes an amplifier and filters (a 90-degree hysteresis filter connected to signal V*GV and circuit 32 and / or a bandpass filter connected to signal V*GV and circuit 33). This estimation can be used as the AC component of the voltage at the terminals of load 10 by using the voltage transformation ratio of voltage transformer 19 (e.g., 1:1).

[0031] The voltage V*GV, source S, and current I*GI signals are fed to demodulator 32, which provides an accurate method for calculating the phase of the current and voltage. In this example, demodulator 32 includes a pair of analog multipliers, each connected in series with a low-pass filter. Using the analog signals V*GV, I*GI, and S, demodulator 32 generates two analog signals: 1 / 2|V*GV|·|S|x COSφ(V*GV / S) and 1 / 2|I*GI|·|S|x COSφ(I*GI / S).

[0032] In this example, the monitor 34 also includes a rectifier 33, which generates three analog signals after low-pass filtering: |V*GV|, |I*GI|, and |S|.

[0033] Microcontroller 24 digitizes the two analog signals generated by demodulator 32 and the three analog signals generated by rectifier 33. Known equations are programmed into microcontroller 24's firmware to calculate the capacitance / impedance of load 10 based on the digital data.

[0034] In view of the above, there is a need in the art for a power supply capable of monitoring the impedance or capacitance of a load connected to the power supply. Summary of the Invention

[0035] This disclosure describes a power supply capable of monitoring the impedance or capacitance of a load connected to the power supply. The power supply includes a current sensor adapted to generate a first alternating signal representing an oscillating current through the load; a voltage sensor adapted to generate a second alternating signal representing an oscillating voltage across the load; and a source conductor adapted to transmit a third alternating signal representing a sinusoidal voltage generated by a sinusoidal oscillator. A microcontroller is coupled to the first, second, and third alternating signals. The microcontroller is adapted to calculate the impedance or capacitance of the load using digital data obtained from the first, second, and third alternating signals.

[0036] This invention can have various modifications and alternatives, specific embodiments of which are shown by way of example in the accompanying drawings and description. However, it should be understood that the drawings and description are not intended to limit the invention to the specific forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives available to those skilled in the art. Attached Figure Description

[0037] To describe embodiments of this disclosure in more detail, reference will now be made to the accompanying drawings, in which:

[0038] Figure 1 is a schematic diagram of a known bipolar power supply suitable for use with a coulomb chuck;

[0039] Figure 2 is a schematic diagram of a known bipolar power supply suitable for use with a coulomb chuck;

[0040] Figure 3 is a schematic diagram of one or more phases of a known power source suitable for use with a coulomb chuck; and

[0041] Figure 4 This is a schematic diagram of one or more phases of a power supply suitable for use with a coulomb chuck. Detailed Implementation

[0042] Figure 4 A preferred embodiment of a power supply with a monitor is shown, which is capable of inducing voltage oscillations on a load connected to the power supply and inducing current-voltage oscillations in the load from a predetermined sinusoidal signal. The monitor is also capable of accurately or approximately measuring:

[0043] Sine wave signal;

[0044] The voltage caused by a sinusoidal signal and its amplitude and phase shift relative to the sinusoidal signal; and

[0045] The current caused by a sinusoidal signal has its amplitude and phase shift relative to the sinusoidal signal.

[0046] The monitor calculates the capacitance or impedance of the load based on the measurement results.

[0047] Compared to the power supply shown in Figures 1-3, the preferred embodiment can provide a simpler and more efficient method for calculating the capacitance or impedance of the load.

[0048] Figure 4 The power supply shown is either unipolar or multiphase. It has terminal 26 connected to load 10. It includes generator 12 and monitor 34.

[0049] In this example, monitor 34 includes a sine wave oscillator 16 for injecting a sinusoidal signal through capacitor 18. Blocking inductor 14 is used to increase the impedance of generator 12 at the frequency of sine wave oscillator 16.

[0050] Due to the combined action of the sinusoidal oscillator 16, capacitor 18, and blocking inductor 14, a first small portion of the alternating current (i.e., without a DC component) flows through the sinusoidal oscillator 16, capacitor 18, blocking inductor 14, generator 12, and returns to ground. A second, larger portion of the alternating current flows through the sinusoidal oscillator 16, capacitor 18, load 10, and returns to ground. A third small portion of the alternating current flows through the sinusoidal oscillator 16, capacitor 18, sensor 28, and returns to ground.

[0051] The second portion of the alternating current is measured using sensor 21, which includes a current transformer (also providing high-voltage insulation), an amplifier, and a filter. The second portion of the alternating current is the precise alternating component of the current flowing through load 10.

[0052] The AC component of the voltage at terminal 26 is measured by sensor 28, which includes a capacitor, a voltage divider, an amplifier, and a filter. Since the voltage difference caused by the primary coil of the current transformer of sensor 21 is negligible, the measurement result can be used as the AC component of the voltage at terminal 26.

[0053] The voltage V, source S, and current I signals are fed to a quadrature demodulator 32, which provides an accurate method for calculating the amplitude and phase of the current and voltage. Using the analog V, I, and S signals, the demodulator 32 generates four analog signals: |V|·COSφ(V / S), |V|·SINφ(V / S), |I|·COSφ(I / S), and |I|·SINφ(I / S).

[0054] Microcontroller 24 uses ADC 24a to digitize four signals. Known equations are programmed into microcontroller 24's firmware to calculate the capacitance / impedance of load 10 based on the digital data.

[0055] Multiple monitors 34 can be used to have... Figure 4 In a multi-pole power supply with a similar architecture to the one shown, each monitor measures the capacitance / impedance to ground at multiple terminals. In this case, differential capacitance / impedance can also be calculated, for example, by using a combination of different sensors at different terminals.

[0056] In addition to the foregoing, this disclosure also considers at least the following embodiments 1-14. It should be noted that any element in these embodiments may also include details relating to that element disclosed in the paragraphs or figures describing preferred embodiments, but not details of other elements disclosed in the same or other paragraphs or figures.

[0057] Example 1

[0058] Example 1 is a power supply capable of monitoring the impedance or capacitance of a load connected to the power supply.

[0059] The power supply includes at least one first terminal that can be connected to a load. The power supply also includes at least one generator that generates a direct current (DC) high voltage between the first terminal and the second terminal.

[0060] If only one generator is used, the power supply is a single-pole power supply. In this case, the first terminal of the generator is connected to the first terminal of the power supply, and the second terminal of the generator is connected to ground.

[0061] If two generators are used, the power supply can be bipolar. In this case, the power supply also includes a second terminal. The first terminal of the first generator is again connected to the first terminal of the power supply, and the second terminal of the first generator is again connected to ground. Furthermore, the first terminal of the second generator can be connected to ground, and the second terminal of the second generator is connected to the second terminal of the power supply.

[0062] The power supply is characterized by having a monitor, which includes an injection circuit, a boost circuit, and a sine wave oscillator. When the power supply is bipolar, the monitor may include another boost circuit.

[0063] The injection circuit is used to allow oscillating current to flow between the first and second terminals. The first terminal of the injection circuit is connected to the first terminal of the power supply, and the second terminal of the injection circuit is connected to ground, or the second terminal of the power supply (if present). Therefore, the injection circuit is connected in parallel with the generator and the load.

[0064] The boost circuit is used to generate an oscillating voltage between the first and second terminals. The first terminal of the boost circuit is connected to the first terminal of the first generator, and the second terminal of the boost circuit is connected to the first terminal of the power supply. Another boost circuit (if any) may be connected between the second terminal of the second generator and the second terminal of the power supply. Therefore, the boost circuit is connected in series with the generator and the load.

[0065] A sinusoidal oscillator is used to generate a sinusoidal voltage at a predetermined frequency. Compared to voltages with different frequencies, sinusoidal voltages are more suitable for situations where the load impedance is frequency-dependent, such as the impedance of a capacitive circuit (like an electronic chuck). Therefore, the load's response to a sinusoidal signal at a predetermined frequency is easier to interpret. However, a sinusoidal oscillator can also be used to sequentially generate a sinusoidal voltage at a first predetermined frequency, then a second sinusoidal voltage at a different predetermined frequency, and so on. The sinusoidal oscillator is coupled to either an injection circuit or a boost circuit. When the sinusoidal oscillator is coupled to the injection circuit, it drives an oscillating current that flows through the load. The boost circuit passively generates the oscillating voltage, thereby offsetting the oscillating current and reducing the oscillating current flowing through the generator. When the sinusoidal oscillator is coupled to the boost circuit, it drives an oscillating voltage and applies it to the load. The injection circuit passively generates an oscillating current, thereby offsetting the oscillating current generated by the oscillating voltage in the load and reducing the oscillating current flowing through the generator.

[0066] Another feature of the power supply is that it has a current sensor, a voltage sensor, and a source conductor, each of which generates an alternating signal, which is used by the microcontroller to calculate the impedance or capacitance of the load.

[0067] Current sensors are used to generate a first alternating signal indicating an oscillating current. Generally, current sensors can be used to convert current flowing through the first terminal of an injection circuit or power supply into voltage.

[0068] A voltage sensor is used to generate a second alternating signal indicating the oscillating voltage. Generally, a voltage sensor may be insensitive to the high DC voltage generated by a generator.

[0069] The source conductor is suitable for transmitting a third alternating signal indicating the sinusoidal voltage generated by the sinusoidal wave generator.

[0070] The microcontroller can be integrated with the power supply or provided as a separate module. The microcontroller is coupled to a first alternating signal, a second alternating signal, and a third alternating signal. The microcontroller can be coupled to the first, second, and third signals sequentially via a multiplexer. Alternatively, the microcontroller can be coupled to these signals simultaneously. The coupling between the microcontroller and the signals can be direct digital communication between the three alternating signals and the microcontroller, or indirect digital communication from other signals derived from the three alternating signals to the microcontroller. For example, these other signals can be obtained through analog demodulation, rectification, filtering (e.g., bandpass filtering at a predetermined frequency), or combinations thereof.

[0071] Furthermore, the microcontroller is adapted to calculate the impedance or capacitance of the load based on digital data derived from the first, second, and third alternating signals. Typically, the microcontroller can be programmable, and the calculation of the load impedance or capacitance can be pre-programmed to implement mathematical formulas well-known in the art.

[0072] It is worth noting that, typically in the presence of noise at DC high voltage, using a third alternating signal or an alternating signal derived from a third alternating signal can advantageously improve the accuracy and / or precision of load impedance or capacitance calculations.

[0073] Example 2

[0074] Example 2 is a power supply as described in Example 1, wherein:

[0075] (i) The injection circuit includes a coupling capacitor, one lead of which is connected to the first terminal of the power supply;

[0076] (ii) The boost circuit includes a blocking inductor and an optional bypass resistor;

[0077] (iii) The sinusoidal oscillator has a first terminal connected to another lead of the coupling capacitor and a second terminal connected to either the power supply or ground; and

[0078] (iv) A blocking inductor is connected between the first terminal of the electric generator and the coupling capacitor.

[0079] Example 3

[0080] Example 3 is a power supply as described in Example 1, wherein:

[0081] (i) The injection circuit includes an LC circuit resonating at a predetermined frequency, or alternatively, an RLC circuit resonating at a predetermined frequency, wherein the injection circuit has a first terminal connected to a first terminal of a power supply, and wherein the injection circuit has a second terminal connected to a second terminal of a power supply or ground.

[0082] (ii) The step-up circuit includes a transformer having a secondary winding connected between a first terminal of the generator and a first terminal of the power supply;

[0083] (iii) A sinusoidal oscillator is connected to the primary winding of the transformer; and

[0084] (iv) The first terminal of the RLC circuit is connected between the first terminal of the generator and the secondary winding of the transformer.

[0085] Example 4

[0086] Example 4 is a power supply as described in any one of Examples 1 to 3, wherein the monitor further includes an analog demodulator.

[0087] The analog demodulator has inputs coupled to a current sensor, a voltage sensor, and a source conductor. The analog demodulator also has outputs coupled to a microcontroller.

[0088] The analog demodulator is configured to perform analog demodulation of the first and second alternating signals relative to a third alternating signal. In other words, the output of the analog demodulator is an analog signal with constant polarity and amplitude, indicating the phase difference between the first and third alternating signals, or between the second and third alternating signals. For example, the output of the analog demodulator may have an amplitude proportional to the cosine or sine of the phase difference between the first and third signals, or between the second and third signals. It is worth noting that using an analog demodulator simplifies the digitization process before the microcontroller uses the signal.

[0089] Optionally, the monitor may also include one or more rectifiers whose inputs are coupled to a first alternating signal, a second alternating signal, and / or a third alternating signal.

[0090] Typically, the output of an analog demodulator and one or more rectifiers is low-pass filtered and digitized by a converter (i.e., ADC). The digitized signal is then transmitted to a microcontroller.

[0091] Example 5

[0092] Example 5 is a power supply as described in Example 4, wherein the analog demodulator includes a secondary demodulator.

[0093] The secondary demodulator is configured to generate four output signals:

[0094] (i) The amplitude of the first alternating signal is multiplied by the cosine of the phase of the first alternating signal relative to the third alternating signal;

[0095] (ii) The amplitude of the first alternating signal multiplied by the sine of the phase of the first alternating signal relative to the third alternating signal;

[0096] (iii) The amplitude of the second alternating signal multiplied by the cosine of the phase of the second alternating signal relative to the third alternating signal; and

[0097] (iv) The amplitude of the second alternating signal multiplied by the sine of the phase of the second alternating signal relative to the third alternating signal.

[0098] In this embodiment, one or more rectifiers may be omitted.

[0099] Example 6

[0100] Example 6 is a power supply as described in Example 4, wherein the analog demodulator includes a first analog multiplier, a first low-pass filter connected in series with the first analog multiplier, a second analog multiplier, and a second low-pass filter connected in series with the second analog multiplier.

[0101] The first analog multiplier is configured to generate the product of a first alternating signal and a third alternating signal. Similarly, the second analog multiplier is configured to generate the product of a second alternating signal and a third alternating signal.

[0102] In this embodiment, the monitor further includes one or more rectifiers, each connected in series with a corresponding low-pass filter. The one or more rectifiers may be connected to one or more of the first alternating signal, the second alternating signal, and the third alternating signal (e.g., directly connected or connected via a multiplexer).

[0103] Example 7

[0104] Example 7 is a power supply as described in any of Examples 1 to 6, wherein the current sensor includes a current transformer, the primary coil of which is connected in series between the boost circuit and the first terminal of the power supply, and the secondary coil is connected to a resistor and the input of an operational amplifier. The operational amplifier is configured as an inverting or non-inverting operational amplifier with fixed gain. As used herein, "inverting operational amplifier" and "non-inverting operational amplifier" are technical terms referring to well-known configurations.

[0105] Example 8

[0106] Example 8 is a power supply as described in any of Examples 1 to 6, wherein the injection circuit includes a resistor through which an oscillating current flows, and wherein a current sensor is adapted to monitor the voltage drop across the resistor. Typically, the current sensor includes a first operational amplifier having an input connected to the high end of the resistor and wired as a voltage follower, and a second operational amplifier having an input connected to the output of the first operational amplifier and wired as a differential amplifier. As used herein, "voltage follower" and "differential amplifier" refer to well-known technical terms for this configuration.

[0107] Example 9

[0108] Example 9 is a power supply as described in any of Examples 1 to 6, wherein the current sensor includes an operational amplifier whose input is connected in series in the injection circuit, and the operational amplifier is wired as a current-to-voltage converter. As used herein, "current-to-voltage converter" is a technical term referring to a well-known configuration.

[0109] Example 10

[0110] Example 10 is a power supply as described in any of Examples 1 to 9, wherein the voltage sensor includes a low-pass or band-pass filter connected to a first terminal of the power supply and ground, and an inverting or non-inverting operational amplifier having an input connected to the low-pass or band-pass filter. Preferably, the low-pass or band-pass filter has a high impedance (i.e., an impedance much higher than that of the injection circuit), so that the current of the voltage sensor is negligible.

[0111] For example, a voltage sensor may include a feedback capacitor connected to the first terminal of a power supply, and an operational amplifier whose input is connected directly or indirectly to the feedback capacitor via a resistor. Typically, the operational amplifier is configured as an inverting or non-inverting operational amplifier with fixed gain. As used herein, "inverting operational amplifier" and "non-inverting operational amplifier" refer to well-known configurations. Furthermore, the input of the operational amplifier may be connected to ground via another resistor.

[0112] Example 11

[0113] Example 11 is a power supply as described in any of Examples 1 to 9, wherein the voltage sensor includes a feedback capacitor connected to a first terminal of the power supply, a first operational amplifier connected to the feedback capacitor and wired as a voltage follower, and a second operational amplifier connected to the output of the first operational amplifier and wired as a differential amplifier. The terms "voltage follower" and "differential amplifier" as used herein are well-known technical terms in the art and refer to a familiar configuration.

[0114] Example 12

[0115] Example 12 is a power supply as described in any one of Examples 1 to 9, wherein the boost circuit includes a transformer having a secondary coil and a primary coil connected in series between the injection circuit and a first terminal of the power supply, wherein the voltage sensor

[0116] Suitable for monitoring voltage drop across the primary coil. Typically, voltage sensors include an operational amplifier, either an inverting or non-inverting operational amplifier with fixed gain. As used herein, "inverting operational amplifier" and "non-inverting operational amplifier" refer to well-known technical terms for these configurations.

[0117] For example, the transformer could be a 1:1 transformer. In this case, the ratio of the oscillating voltage to the voltage monitored by the voltage sensor before the amplifier gain is applied is 1:1.

[0118] Example 13

[0119] Example 13 is a method for monitoring the impedance or capacitance of a load connected to a power source. The method includes the following steps: providing a power source according to any one of Examples 1 to 12, and causing a monitor to display or store digital data representing the impedance or capacitance of the load.

[0120] Example 14

[0121] Example 14 is the method as described in Example 13, wherein the load is a coulomb-type electrostatic chuck. The method further includes clamping a semiconductor or liquid crystal panel by applying a direct current (DC) high voltage to the chuck via a power supply.

Claims

1. A power supply capable of monitoring the impedance or capacitance of a load connected to the power supply, characterized in that, The power source includes: The first terminal is connected to the load; A generator, adapted to generate a DC high voltage between a first terminal and a second terminal, wherein the first terminal of the generator is connected to a first terminal of the power supply, and the second terminal of the generator is connected to ground; and Monitor, The monitor includes: An injection circuit for flowing oscillating current between a first terminal and a second terminal, wherein the first terminal of the injection circuit is connected to the first terminal of the power supply, and the... The second terminal of the injection circuit is connected to ground or the second terminal of the power supply. A boost circuit is used to generate an oscillating voltage between a first terminal and a second terminal, wherein the first terminal of the boost circuit is connected to the first terminal of the generator, and the second terminal of the boost circuit is connected to the first terminal of the power supply. A sinusoidal oscillator for generating a sinusoidal voltage at a predetermined frequency, wherein the sinusoidal oscillator has terminals coupled to one of an injection circuit and a boost circuit; A current sensor is used to generate a first alternating signal indicating the oscillating current; The current sensor includes a transformer, which has the following characteristics: The primary coil is connected in series between the boost circuit and the first terminal of the power supply; and The secondary coil is connected to the input terminal of the inverting or non-inverting operational amplifier; A voltage sensor is used to generate a second alternating signal representing the oscillating voltage; The source conductor is used to transmit a third alternating signal representing a sinusoidal voltage; and A microcontroller is coupled to the first alternating signal, the second alternating signal, and the third alternating signal; The microcontroller is adapted to calculate the impedance or capacitance of the load using digital data derived from the first alternating signal, the second alternating signal, and the third alternating signal.

2. The power supply according to claim 1, characterized in that, The injection circuit includes a coupling capacitor, one lead of which is connected to a first terminal of the power supply. The sinusoidal oscillator, wherein a first end of the sinusoidal oscillator is connected to the other end of the coupling capacitor, and a second end of the sinusoidal oscillator is connected to ground or the second end of the power supply; and The boost circuit includes a blocking inductor; and The blocking inductor is connected between the first terminal of the generator and the coupling capacitor.

3. The power supply according to claim 1, characterized in that, Also includes: An analog demodulator having an input coupled to the current sensor, the voltage sensor, and the source conductor; The analog demodulator has an output coupled to the microcontroller; The analog demodulator is configured to perform analog demodulation of the first alternating signal and the second alternating signal relative to the third alternating signal.

4. The power supply according to claim 3, characterized in that, The analog demodulator includes a secondary demodulator configured to generate four output signals: The amplitude of the first alternating signal is multiplied by the cosine of the phase of the first alternating signal relative to the third alternating signal; The amplitude of the first alternating signal is multiplied by the sine value of the phase of the first alternating signal relative to the third alternating signal; The amplitude of the second alternating signal multiplied by the cosine of the phase of the second alternating signal relative to the third alternating signal; and The amplitude of the second alternating signal is multiplied by the sine value of the phase of the second alternating signal relative to the third alternating signal.

5. The power supply according to claim 1, characterized in that, The voltage sensor includes: A low-pass or band-pass filter is connected to the first terminal of the power supply and the ground; and An inverting or non-inverting operational amplifier whose input is connected to the low-pass or band-pass filter.

6. A method for monitoring the impedance or capacitance of a load connected to a power source, characterized in that, The power source includes a first terminal connectable to the load, and a generator adapted to generate a direct current (DC) high voltage between the first and second terminals, wherein the first terminal of the generator is connected to the first terminal of the power source, and the second terminal of the generator is connected to ground, the method comprising: Provide a monitor for the power supply; and The monitor displays or stores digital data representing the impedance or capacitance of the load. The monitor mentioned above includes: An injection circuit is provided for flowing an oscillating current between a first terminal and a second terminal, wherein the first terminal of the injection circuit is connected to a first terminal of the power supply, and the second terminal of the injection circuit is connected to ground or a second terminal of the power supply. A boost circuit is used to generate an oscillating voltage between a first terminal and a second terminal, wherein the first terminal of the boost circuit is connected to the first terminal of the generator, and the second terminal of the boost circuit is connected to the first terminal of the power supply. A sinusoidal oscillator for generating a sinusoidal voltage at a predetermined frequency, wherein the sinusoidal oscillator has terminals coupled to one of the injection circuit and the boost circuit; A current sensor is used to generate a first alternating signal indicating the oscillating current; The current sensor includes a transformer, which has the following characteristics: The primary coil is connected in series between the boost circuit and the first terminal of the power supply; and The secondary coil is connected to the input terminal of the inverting or non-inverting operational amplifier; A voltage sensor is used to generate a second alternating signal representing the oscillating voltage; The source conductor is used to transmit a third alternating signal representing a sinusoidal voltage; and A microcontroller is coupled to the first alternating signal, the second alternating signal, and the third alternating signal; The microcontroller is adapted to calculate the impedance or capacitance of the load using digital data derived from the first alternating signal, the second alternating signal, and the third alternating signal.

7. The method according to claim 6, characterized in that, The injection circuit includes a coupling capacitor, one lead of which is connected to a first terminal of the power supply. The sinusoidal oscillator, wherein a first end of the sinusoidal oscillator is connected to the other end of the coupling capacitor, and a second end of the sinusoidal oscillator is connected to ground or the second end of the power supply; and The boost circuit includes a blocking inductor; and The blocking inductor is connected between the first terminal of the generator and the coupling capacitor.

8. The method according to claim 6, characterized in that, Also includes: An analog demodulator has an input coupled to the current sensor, the voltage sensor, and the source conductor; The analog demodulator has an output coupled to the microcontroller; The analog demodulator is configured to perform analog demodulation of the first alternating signal and the second alternating signal relative to the third alternating signal.

9. The method according to claim 8, characterized in that, The analog demodulator includes a secondary demodulator configured to generate four output signals: The amplitude of the first alternating signal is multiplied by the cosine of the phase of the first alternating signal relative to the third alternating signal; The amplitude of the first alternating signal is multiplied by the sine value of the phase of the first alternating signal relative to the third alternating signal; The amplitude of the second alternating signal multiplied by the cosine of the phase of the second alternating signal relative to the third alternating signal; and The amplitude of the second alternating signal is multiplied by the sine value of the phase of the second alternating signal relative to the third alternating signal.

10. The method according to claim 6, characterized in that, The voltage sensor includes: A low-pass or band-pass filter is connected to the first terminal of the power supply and ground; and An inverting or non-inverting operational amplifier whose input is connected to the low-pass or band-pass filter.

11. The method according to claim 6, characterized in that, The load is a coulomb electrostatic chuck, and the method further includes applying a high DC voltage to the chuck via a power supply to clamp a semiconductor or liquid crystal panel.

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