Voltage control circuit and system for a bipolar electrostatic chuck

Abstract

This application discloses a voltage control circuit and system for a bipolar electrostatic chuck. The voltage control circuit includes a reference circuit, a voltage output circuit, a positive sampling adjustment circuit, a negative sampling adjustment circuit, and a selection control circuit. The positive sampling adjustment circuit samples the positive output voltage to generate a first sampling voltage, and generates a first adjustment signal when the sum of the first sampling voltage and the reference voltage is not equal to zero. The negative sampling adjustment circuit samples the negative output voltage to generate a second sampling voltage, and generates a second adjustment signal when the sum of the second sampling voltage and the reference voltage is not equal to zero. The selection control circuit selects between the first and second adjustment signals and outputs a target adjustment signal, so that the voltage output circuit adjusts the positive or negative output voltage based on the target adjustment signal. This voltage control circuit improves the stability of the output voltage through closed-loop control of sampling, comparison, and adjustment, thereby improving the adsorption effect of the bipolar electrostatic chuck.

Description

Technical Field

[0001] This application relates to the field of voltage control technology for bipolar electrostatic chucks, specifically to a voltage control circuit and system for a bipolar electrostatic chuck. Background Technology

[0002] Bipolar electrostatic chucks are widely used in the processing of semiconductor wafers, precision glass substrates and other devices. Their adsorption and fixation effect depends entirely on the stability of the bipolar high voltage output of the power supply. Stable high voltage output is the core prerequisite for ensuring that the adsorption force of the electrostatic chuck meets the standard and avoiding device displacement and detachment during processing. If the output voltage of the power supply fluctuates or drifts, it will directly lead to insufficient adsorption capacity of the electrostatic chuck, which will seriously affect the device processing accuracy and production yield.

[0003] However, the power supply of existing bipolar electrostatic chucks is prone to instability in actual operation, such as output voltage deviation, excessive ripple, and voltage sudden change when switching polarity. It cannot continuously provide the electrostatic chuck with a stable high voltage that meets the requirements, which leads to the decay of the electrostatic chuck's adsorption capacity and the instability of the adsorption effect, making it difficult to meet the high requirements of precision device processing. Summary of the Invention

[0004] This application provides a voltage control circuit and system for a bipolar electrostatic chuck, which can improve the stability of the output voltage of the bipolar electrostatic chuck and enhance its adsorption effect.

[0005] To address the aforementioned technical problems, the embodiments of this application provide the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a voltage control circuit for a bipolar electrostatic chuck, the voltage control circuit comprising: a reference circuit, a voltage output circuit, a positive sampling adjustment circuit, a negative sampling adjustment circuit, and a selection control circuit;

[0007] The input terminal of the reference circuit is used to connect to a set voltage, and the output terminal of the reference circuit is connected to the second input terminal of the positive sampling adjustment circuit and the second input terminal of the negative sampling adjustment circuit. The reference circuit is used to convert the input set voltage into a reference voltage.

[0008] The first output terminal of the voltage output circuit is used to output a positive output voltage, and the second output terminal of the voltage output circuit is used to output a negative output voltage.

[0009] The first input terminal of the positive sampling adjustment circuit is connected to the first output terminal of the voltage output circuit and is used to receive the positive output voltage of the voltage output circuit. The second input terminal of the positive sampling adjustment circuit is used to receive the reference voltage. The output terminal of the positive sampling adjustment circuit is connected to the first input terminal of the selection control circuit. The positive sampling adjustment circuit is used to sample the positive output voltage, generate a first sampling voltage, compare the first sampling voltage with the reference voltage, and generate a first adjustment signal in response to the result that the sum of the first sampling voltage and the reference voltage is not equal to zero.

[0010] The first input terminal of the negative sampling adjustment circuit is connected to the second output terminal of the voltage output circuit for receiving the negative output voltage of the voltage output circuit. The second input terminal of the negative sampling adjustment circuit is used to receive the reference voltage. The output terminal of the negative sampling adjustment circuit is connected to the second input terminal of the selection control circuit. The negative sampling adjustment circuit is used to sample the negative output voltage, generate a second sampling voltage, compare the second sampling voltage with the reference voltage, and generate a second adjustment signal in response to the result that the sum of the second sampling voltage and the reference voltage is not equal to zero.

[0011] The output terminal of the selection control circuit is connected to the input terminal of the voltage output circuit, and is used to select the first adjustment signal and the second adjustment signal to output a target adjustment signal, so that the voltage output circuit adjusts the positive output voltage or the negative output voltage based on the target adjustment signal, wherein the target adjustment signal is the first adjustment signal or the second adjustment signal.

[0012] In some embodiments, the positive sampling adjustment circuit includes a first sampling unit and a positive feedback adjustment unit;

[0013] The first terminal of the first sampling unit is connected to the first output terminal of the voltage output circuit, the second terminal of the first sampling unit is grounded, and the third terminal of the first sampling unit is connected to the first input terminal of the positive feedback adjustment unit. The first sampling unit is used to sample the positive output voltage and generate a first sampling voltage.

[0014] The second input terminal of the positive feedback adjustment unit is used to connect to the reference voltage, and the output terminal of the positive feedback adjustment unit is connected to the first input terminal of the selection control circuit. The positive feedback adjustment unit is used to compare the first sampled voltage with the reference voltage, and in response to the result that the sum of the first sampled voltage and the reference voltage is not equal to zero, outputs the first adjustment signal.

[0015] In some embodiments, the positive feedback adjustment unit includes a first superposition unit and a first comparison unit;

[0016] The first end of the first superposition unit is connected to the third end of the first sampling unit, the second end of the first superposition unit is used to connect to the reference voltage, the third end of the first superposition unit is connected to the first input end of the first comparison unit, and the first superposition unit is used to superimpose the first sampled voltage and the reference voltage to generate a first total voltage.

[0017] The second input terminal of the first comparison unit is grounded, and the output terminal of the first comparison unit is connected to the first input terminal of the selection control circuit. The first comparison unit is used to compare the first total voltage and the zero potential, and outputs the first adjustment signal in response to the result that the first total voltage and the zero potential are not equal.

[0018] In some embodiments, the negative sampling adjustment circuit includes a second sampling unit and a negative feedback adjustment unit;

[0019] The first terminal of the second sampling unit is connected to the second output terminal of the voltage output circuit, the second terminal of the second sampling unit is grounded, and the third terminal of the second sampling unit is connected to the first input terminal of the negative feedback adjustment unit. The second sampling unit is used to sample the negative output voltage and generate a second sampling voltage.

[0020] The second input terminal of the negative feedback adjustment unit is used to connect to the reference voltage, and the output terminal of the negative feedback adjustment unit is connected to the second input terminal of the selection control circuit. The negative feedback adjustment unit is used to compare the second sampled voltage with the reference voltage, and in response to the result that the sum of the second sampled voltage and the reference voltage is not equal to zero, outputs the second adjustment signal.

[0021] In some embodiments, the negative feedback adjustment unit includes an inverting unit, a second superposition unit, and a second comparison unit;

[0022] The negative input terminal of the inverting unit is connected to the third terminal of the second sampling unit, the positive input terminal of the inverting unit is grounded, and the output terminal of the inverting unit is connected to the first terminal of the second superposition unit. The inverting unit is used to invert the second sampling voltage to generate the inverted second sampling voltage.

[0023] The second end of the second superposition unit is used to connect to the reference voltage, and the third end of the second superposition unit is connected to the first input end of the second comparison unit. The second superposition unit is used to superimpose the inverted second sampled voltage with the reference voltage to generate a second total voltage.

[0024] The second input terminal of the second comparison unit is grounded, and the output terminal of the second comparison unit is connected to the second input terminal of the selection control circuit. The second comparison unit is used to compare the second total voltage and the zero potential, and outputs the second adjustment signal in response to the result that the second total voltage and the zero potential are not equal.

[0025] In some embodiments, the selection control circuit includes a first diode and a second diode;

[0026] The anode of the first diode is connected to the output terminal of the positive sampling adjustment circuit, the anode of the second diode is connected to the output terminal of the negative sampling adjustment circuit, and the cathodes of the first diode and the second diode are connected together to the input terminal of the voltage output circuit.

[0027] In some embodiments, the voltage output circuit includes a driving circuit and an output circuit;

[0028] The input terminal of the driving circuit is connected to the output terminal of the selection control circuit, the output terminal of the driving circuit is connected to the input terminal of the output circuit, the first output terminal of the output circuit is connected to the first input terminal of the positive sampling adjustment circuit, and the second output terminal of the output circuit is connected to the first input terminal of the negative sampling adjustment circuit.

[0029] The driving circuit is used to adjust the positive or negative output voltage of the output circuit according to the target adjustment signal.

[0030] In some embodiments, the driving circuit includes a driving unit, a switching unit, a protection unit, and an absorption unit;

[0031] The input terminal of the driving unit is connected to the output terminal of the selection control circuit, and the output terminal of the driving unit is connected to the control terminal of the switching unit. The driving unit is used to drive the switching unit to turn on and off according to the target adjustment signal, so as to adjust the positive output voltage or negative output voltage of the output circuit.

[0032] The absorption unit is connected to the switching unit and is used to absorb the reverse turn-off voltage generated by the switching unit during the turn-off process.

[0033] The protection unit is connected to the switching unit and is used to absorb the high-frequency ringing signal generated by the switching unit during the turn-off process.

[0034] In some embodiments, the output circuit includes an energy conversion unit and a polarity conversion unit;

[0035] The primary side of the energy conversion unit is connected to the switching unit and the input power supply respectively, and the secondary side of the energy conversion unit is connected to the polarity conversion unit. The energy conversion unit is used to convert the DC signal output by the input power supply into an AC signal during the switching unit's on and off process. The polarity conversion unit is used to output a positive output voltage and a negative output voltage based on the AC signal.

[0036] In a second aspect, embodiments of this application provide a voltage control system for a bipolar electrostatic chuck, the voltage control system comprising a bipolar electrostatic chuck and a voltage control circuit as described above.

[0037] Compared to conventional technologies, the voltage control circuits provided in the various embodiments of this application include a reference circuit, a voltage output circuit, a positive sampling adjustment circuit, a negative sampling adjustment circuit, and a selection control circuit. The first input terminal of the positive sampling adjustment circuit is connected to the first output terminal of the voltage output circuit; the second input terminal of the positive sampling adjustment circuit is connected to the output terminal of the reference circuit; the output terminal of the positive sampling adjustment circuit is connected to the first input terminal of the selection control circuit; the first input terminal of the negative sampling adjustment circuit is connected to the second output terminal of the voltage output circuit; the second input terminal of the negative sampling adjustment circuit is connected to the output terminal of the reference circuit; the output terminal of the negative sampling adjustment circuit is connected to the second input terminal of the selection control circuit; and the output terminal of the selection control circuit is connected to the input terminal of the voltage output circuit.

[0038] The reference circuit converts the input set voltage into a reference voltage. The first terminal of the voltage output circuit outputs a positive output voltage, and the second terminal outputs a negative output voltage. The positive sampling adjustment circuit samples the positive output voltage to generate a first sampled voltage and compares it with the reference voltage. When the sum of the first sampled voltage and the reference voltage is not equal to zero, the positive sampling adjustment circuit generates a first adjustment signal. The negative sampling adjustment circuit samples the negative output voltage to generate a second sampled voltage and compares it with the reference voltage. When the sum of the second sampled voltage and the reference voltage is not equal to zero, the negative sampling adjustment circuit generates a second adjustment signal. The selection control circuit selects between the first and second adjustment signals and outputs a target adjustment signal, causing the voltage output circuit to adjust either the positive or negative output voltage based on the target adjustment signal, where the target adjustment signal is either the first or the second adjustment signal.

[0039] This voltage control circuit achieves precise control of the positive and negative output voltages through closed-loop control of sampling, comparison, and adjustment. This avoids voltage fluctuations caused by changes in the adsorption state of the bipolar electrostatic chuck, improves the stability of the positive and negative output voltages, and thus enhances the adsorption effect of the bipolar electrostatic chuck. Attached Figure Description

[0040] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0041] Figure 1 This is a schematic diagram of the structure of a voltage control circuit provided in an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the structure of a voltage control circuit provided in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of the structure of a voltage control circuit provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of a voltage output circuit provided in an embodiment of this application;

[0045] Figure 5 This is a schematic diagram of the circuit structure of a reference circuit, a positive sampling adjustment circuit, and a negative sampling adjustment circuit provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of the circuit structure of a driving unit provided in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of the circuit structure of a voltage output circuit provided in an embodiment of this application. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0050] Please see Figure 1 , Figure 1 This is a schematic diagram of the voltage control circuit for a bipolar electrostatic chuck provided in an embodiment of the present invention. Figure 1As shown, the voltage control circuit 100 includes a reference circuit 10, a voltage output circuit 20, a positive sampling adjustment circuit 30, a negative sampling adjustment circuit 40, and a selection control circuit 50. The first input terminal of the positive sampling adjustment circuit 30 is connected to the first output terminal of the voltage output circuit 20, the second input terminal of the positive sampling adjustment circuit 30 is connected to the output terminal of the reference circuit 10, the output terminal of the positive sampling adjustment circuit 30 is connected to the first input terminal of the selection control circuit 50, the first input terminal of the negative sampling adjustment circuit 40 is connected to the second output terminal of the voltage output circuit 20, the second input terminal of the negative sampling adjustment circuit 40 is connected to the output terminal of the reference circuit 10, the output terminal of the negative sampling adjustment circuit 40 is connected to the second input terminal of the selection control circuit 50, and the output terminal of the selection control circuit 50 is connected to the input terminal of the voltage output circuit 20.

[0051] The input terminal of the reference circuit 10 is used to connect a set voltage. The reference circuit 10 converts the input set voltage into a reference voltage. In this embodiment, the set voltage is a positive voltage, and the reference voltage is a negative voltage. The first terminal of the voltage output circuit 20 outputs a positive output voltage, and the second terminal of the voltage output circuit 20 outputs a negative output voltage.

[0052] The positive sampling adjustment circuit 30 samples the positive output voltage to generate a first sample voltage and compares the first sample voltage with a reference voltage. If the sum of the first sample voltage and the reference voltage is not equal to zero, the positive sampling adjustment circuit 30 generates and outputs a first adjustment signal. If the sum of the first sample voltage and the reference voltage is equal to zero, the positive sampling adjustment circuit 30 does not generate a first adjustment signal.

[0053] The negative sampling adjustment circuit 40 samples the negative output voltage to generate a second sampling voltage and compares the second sampling voltage with the reference voltage. If the sum of the second sampling voltage and the reference voltage is not equal to zero, the negative sampling adjustment circuit 40 generates and outputs a second adjustment signal. If the sum of the second sampling voltage and the reference voltage is equal to zero, the negative sampling adjustment circuit 40 no longer outputs a second adjustment signal.

[0054] If the selection control circuit 50 receives the first adjustment signal, it outputs the target adjustment signal, so that the voltage output circuit 20 adjusts the positive output voltage based on the target adjustment signal, wherein the target adjustment signal is the first adjustment signal.

[0055] If the selection control circuit 50 receives the second adjustment signal, it outputs the target adjustment signal, causing the voltage output circuit 20 to adjust the negative output voltage based on the target adjustment signal, wherein the target adjustment signal is the second adjustment signal.

[0056] If the selection control circuit 50 receives both the first adjustment signal and the second adjustment signal, it selects between them and outputs a target adjustment signal. If the target adjustment signal is the first adjustment signal, the voltage output circuit 20 adjusts the positive output voltage based on the target adjustment signal. If the target adjustment signal is the second adjustment signal, the voltage output circuit 20 adjusts the negative output voltage based on the target adjustment signal.

[0057] When the positive output voltage fails to reach the preset positive output voltage, or when the negative output voltage fails to reach the preset negative output voltage, the bipolar electrostatic chuck's adsorption force is insufficient, resulting in poor adsorption performance. Therefore, in this embodiment, the voltage control circuit 100 samples the positive output voltage through the positive sampling adjustment circuit 30 to generate a first sampling voltage. If the positive output voltage fails to reach the preset positive output voltage, the sum of the first sampling voltage and the reference voltage is not equal to zero. The voltage output circuit 20 then generates a first adjustment signal and adjusts the positive output voltage based on this signal until the positive output voltage reaches the preset positive output voltage. At this point, the sum of the first sampling voltage and the reference voltage equals zero, and the voltage output circuit 20 no longer generates the first adjustment signal.

[0058] Similarly, in this embodiment, the voltage control circuit 100 also samples the negative output voltage through the negative sampling adjustment circuit 40 to generate a second sampling voltage. If the negative output voltage does not reach the negative preset output voltage, the sum of the second sampling voltage and the reference voltage is not equal to zero. Then, the voltage output circuit 20 generates a second adjustment signal and adjusts the negative output voltage based on the second adjustment signal until the negative output voltage reaches the negative preset output voltage. At that point, the sum of the second sampling voltage and the reference voltage is equal to zero, and the voltage output circuit 20 no longer generates a second adjustment signal.

[0059] If the positive output voltage does not reach the preset positive output voltage, the positive sampling adjustment circuit 30 outputs the first adjustment signal. If the negative output voltage does not reach the preset negative output voltage, the negative sampling adjustment circuit 40 outputs the second adjustment signal. The selection control circuit 50 selects between the first and second adjustment signals and outputs the target adjustment signal, so that the voltage output circuit 20 adjusts the positive or negative output voltage based on the target adjustment signal.

[0060] It should be noted that the value of the set voltage can be determined based on the magnitude of the positive preset output voltage. If the positive preset output voltage increases (the negative preset output voltage decreases), the set voltage will increase accordingly. If the positive preset output voltage decreases (the negative preset output voltage increases), the set voltage will decrease accordingly.

[0061] The set voltage can adjust the magnitude of the positive preset output voltage. If it is necessary to increase the positive preset output voltage, the set voltage can be increased, and the absolute value of the reference voltage will increase accordingly, so that the sum of the adjusted reference voltage and the first sampling voltage is not equal to zero. The positive sampling adjustment circuit 30 outputs a first adjustment signal, and the output circuit adjusts the positive output voltage based on the first adjustment signal until the positive output voltage reaches the increased positive preset output voltage, or, so that the sum of the adjusted reference voltage and the second sampling voltage is not equal to zero. The negative sampling adjustment circuit 40 outputs a second adjustment signal, and the output circuit adjusts the negative output voltage based on the second adjustment signal until the negative output voltage reaches the decreased negative preset output voltage.

[0062] Therefore, the voltage control circuit 100 achieves precise control of the positive and negative output voltages through closed-loop control of sampling, comparison, and adjustment, avoiding the influence of output voltage fluctuations of the bipolar electrostatic chuck on the adsorption state, improving the stability of the positive and negative output voltages, and thus improving the adsorption effect of the bipolar electrostatic chuck.

[0063] Please see Figure 2 , Figure 2 This is a schematic diagram of a voltage control circuit provided in an embodiment of this application, as shown below. Figure 2 As shown, the positive sampling adjustment circuit 30 includes a first sampling unit 31 and a positive feedback adjustment unit 32. The first end of the first sampling unit 31 is connected to the first output end of the voltage output circuit 20, the second end of the first sampling unit 31 is grounded, the third end of the first sampling unit 31 is connected to the first input end of the positive feedback adjustment unit 32, the second input end of the positive feedback adjustment unit 32 is used to connect to the reference voltage, and the output end of the positive feedback adjustment unit 32 is connected to the first input end of the selection control circuit 50.

[0064] The first sampling unit 31 samples the positive output voltage to generate a first sampling voltage. The positive feedback adjustment unit 32 compares the first sampling voltage with the reference voltage. When the sum of the first sampling voltage and the reference voltage is not equal to zero, the positive feedback adjustment unit 32 outputs a first adjustment signal.

[0065] In some embodiments, the negative sampling adjustment circuit 40 includes a second sampling unit 41 and a negative feedback adjustment unit 42. The first terminal of the second sampling unit 41 is connected to the second output terminal of the voltage output circuit 20, the second terminal of the second sampling unit 41 is grounded, the third terminal of the second sampling unit 41 is connected to the first input terminal of the negative feedback adjustment unit 42, the second input terminal of the negative feedback adjustment unit 42 is used to connect to a reference voltage, and the output terminal of the negative feedback adjustment unit 42 is connected to the second input terminal of the selection control circuit 50.

[0066] The second sampling unit 41 samples the negative output voltage to generate a second sampling voltage. The negative feedback adjustment unit 42 compares the second sampling voltage with the reference voltage. When the sum of the second sampling voltage and the reference voltage is not equal to zero, the negative feedback adjustment unit 42 outputs a second adjustment signal.

[0067] Therefore, in this embodiment, sampling is performed by a sampling unit (first sampling unit or second sampling unit), and adjustment is performed by a feedback adjustment unit (positive feedback adjustment unit or negative feedback adjustment unit). This achieves decoupling of sampling and adjustment functions and independent design of positive and negative voltage sampling, reduces signal crosstalk, improves sampling accuracy and the effectiveness of adjustment signals, thereby improving the stability of the output voltage.

[0068] In some embodiments, please refer to Figure 3 The first sampling unit 31 includes a first voltage divider unit 311 and a first buffer unit 312. The first end of the first voltage divider unit 311 is connected to the first output end of the voltage output circuit 20, the second end of the first voltage divider unit 311 is grounded, and the first buffer unit 312 is connected between the third end of the first voltage divider unit 311 and the first input end of the positive feedback adjustment unit 32.

[0069] The first voltage divider unit 311 divides the positive output voltage to generate the first sampling voltage. The first buffer unit 312 outputs the first sampling voltage to the first input terminal of the positive feedback adjustment unit 32. The first buffer unit 312 is used to reduce the input impedance to the positive feedback adjustment unit 32.

[0070] Therefore, in this embodiment, the first voltage divider unit 311 achieves accurate voltage division sampling of the positive output voltage, converting the high voltage into a low voltage signal that can be recognized by subsequent circuits. The first buffer unit 312 isolates and buffers the sampling signal, effectively reducing the impedance influence of the subsequent circuits on the sampling stage, reducing signal transmission loss and interference, improving the accuracy and stability of the first sampling voltage, and providing an accurate signal basis for subsequent feedback adjustment.

[0071] Please continue reading. Figure 3 The positive feedback adjustment unit 32 includes a first superposition unit 321 and a first comparison unit 322. The first end of the first superposition unit 321 is connected to the third end of the first sampling unit 31. The second end of the first superposition unit 321 is used to connect to a reference voltage. The third end of the first superposition unit 321 is connected to the first input end of the first comparison unit 322. The second input end of the first comparison unit 322 is grounded. The output end of the first comparison unit 322 is connected to the first input end of the selection control circuit 50.

[0072] The first superposition unit 321 superimposes the first sampled voltage and the reference voltage to generate a first total voltage. The first comparison unit 322 compares the first total voltage with the zero potential. When the first total voltage is not equal to the zero potential, the first comparison unit 322 generates and outputs a first adjustment signal. When the first total voltage is equal to the zero potential, the first comparison unit 322 no longer outputs the first adjustment signal.

[0073] In this embodiment, the zero point is used as the judgment benchmark to realize the intuitive detection of the deviation between the first sampled voltage and the reference voltage. When there is a deviation between the two, the first total voltage deviates from the zero potential. At this time, the first comparison unit 322 generates and outputs the first adjustment signal in a timely manner. When the deviation is eliminated, the output stops. In this way, the accurate and fast judgment of the deviation of the positive output voltage and the on-demand generation of the adjustment signal are realized, providing a direct and reliable signal basis for the subsequent accurate adjustment of the positive output voltage, and ensuring the timeliness and accuracy of voltage adjustment.

[0074] Please continue reading. Figure 3 The second sampling unit 41 includes a second voltage divider unit 411 and a second buffer unit 412. The first end of the second voltage divider unit 411 is connected to the second output end of the voltage output circuit 20, and the second end of the second voltage divider unit 411 is grounded. The second buffer unit 412 is connected between the third end of the second voltage divider unit 411 and the second input end of the negative feedback adjustment unit 42.

[0075] The second voltage divider unit 411 divides the negative output voltage to generate the second sampling voltage. The second buffer unit 412 outputs the second sampling voltage to the second input terminal of the negative feedback adjustment unit 42. The second buffer unit 412 is used to reduce the input impedance to the negative feedback adjustment unit.

[0076] In this embodiment, the second voltage divider unit 411 achieves accurate voltage division sampling of the negative output voltage, converting the high voltage into a low voltage signal that can be recognized by subsequent circuits. The second buffer unit 412 isolates and buffers the sampling signal, effectively reducing the impedance influence of the subsequent circuit on the sampling stage, reducing signal transmission loss and interference, improving the accuracy and stability of the second sampling voltage, and providing an accurate signal basis for subsequent feedback adjustment.

[0077] Please continue reading. Figure 3The negative feedback adjustment unit 42 includes an inverting unit 421, a second superposition unit 422, and a second comparison unit 423. The negative input terminal of the inverting unit 421 is connected to the third terminal of the second sampling unit 41, the positive input terminal of the inverting unit 421 is grounded, the output terminal of the inverting unit 421 is connected to the first terminal of the second superposition unit 422, the second terminal of the second superposition unit 422 is used to connect to the reference voltage, the third terminal of the second superposition unit 422 is connected to the first input terminal of the second comparison unit 423, the second input terminal of the second comparison unit 423 is grounded, and the output terminal of the second comparison unit 423 is connected to the second input terminal of the selection control circuit.

[0078] The inverting unit 421 inverts the second sampled voltage to generate the inverted second sampled voltage. The second superposition unit 422 superimposes the inverted second sampled voltage with the reference voltage to generate the second total voltage. The second comparison unit 423 compares the second total voltage with the zero potential. When the second total voltage is not equal to the zero potential, the second comparison unit 423 generates and outputs a second adjustment signal. When the second total voltage is equal to the zero potential, the second comparison unit 423 no longer outputs the second adjustment signal.

[0079] In this embodiment, the zero point is used as the judgment benchmark to realize the intuitive detection of the deviation between the second sampling voltage and the reference voltage. When there is a deviation between the two, the second total voltage deviates from the zero potential. At this time, the second comparison unit 423 generates and outputs the second adjustment signal in a timely manner. When the deviation is eliminated, the output stops. This realizes the accurate and rapid judgment of the negative output voltage deviation and the on-demand generation of the adjustment signal, providing a direct and reliable signal basis for the subsequent accurate adjustment of the negative output voltage, and ensuring the timeliness and accuracy of voltage adjustment.

[0080] Please see Figure 4 , Figure 4 This is a schematic diagram of the circuit structure of a voltage control circuit provided in an embodiment of this application, as shown below. Figure 4 As shown, the voltage output circuit 20 includes a drive circuit 21 and an output circuit 22. The input terminal of the drive circuit 21 is connected to the output terminal of the selection control circuit 50, the output terminal of the drive circuit 21 is connected to the input terminal of the output circuit 22, the first output terminal of the output circuit 22 is connected to the first input terminal of the positive sampling adjustment circuit 30, and the second output terminal of the output circuit 22 is connected to the first input terminal of the negative sampling adjustment circuit 40.

[0081] If the drive circuit 21 receives the target adjustment signal, it adjusts the positive or negative output voltage of the output circuit 22 according to the target adjustment signal.

[0082] If the target adjustment signal is the first adjustment signal, the drive circuit 21 adjusts the positive output voltage of the output circuit 22 according to the first adjustment signal until the positive output voltage is adjusted to the positive preset output voltage.

[0083] If the target adjustment signal is the second adjustment signal, the drive circuit 21 adjusts the negative output voltage of the output circuit 22 according to the second adjustment signal until the negative output voltage is adjusted to the negative preset output voltage.

[0084] In this embodiment, the voltage output circuit 20 is divided into a drive circuit 21 and an output circuit 22, realizing independent design of drive control and energy conversion output, and reducing interference.

[0085] In some embodiments, please continue reading Figure 4 The driving circuit 21 includes a driving unit 211, a switching unit 212, a protection unit 213, and an absorption unit 214. The input terminal of the driving unit 211 is connected to the output terminal of the selection control circuit 50, and the output terminal of the driving unit 211 is connected to the control terminal of the switching unit 212.

[0086] The output circuit 22 includes an energy conversion unit 221 and a polarity conversion unit 222. The primary side of the energy conversion unit 221 is connected to the switching unit 212 via the protection unit 213. The primary side of the energy conversion unit 221 is also connected to the input power supply 200. The secondary side of the energy conversion unit 221 is connected to the polarity conversion unit 222.

[0087] The drive unit 211 receives the target adjustment signal and outputs a corresponding drive signal based on the target adjustment signal. The drive signal drives the switch unit 212 to turn on and off. During the process of the switch unit 212 turning on and off, the energy conversion unit 221 converts the DC signal output from the input power supply 200 into an AC signal, and the polarity conversion unit 222 converts the polarity of the AC signal, outputting a positive output voltage and a negative output voltage.

[0088] During the adjustment of the positive and negative output voltages, when the switching unit 212 is turned off, a reverse turn-off voltage and a high-frequency ringing signal are generated. These signals can cause electromagnetic interference (EMI) to surrounding devices, affecting their normal operation. Furthermore, the reverse turn-off voltage and high-frequency ringing signal can cause significant losses in the MOSFET, potentially leading to its burnout or breakdown.

[0089] For the reasons stated above, in this embodiment, the absorption unit 214 is connected to the switching unit 212 to absorb the reverse turn-off voltage generated during the turn-off process of the switching unit 212. The protection unit 213 is connected to the switching unit 212 to absorb the high-frequency ringing signal generated during the turn-off process of the switching unit 212.

[0090] Therefore, in this embodiment of the application, when adjusting the positive or negative output voltage, the absorption unit 214 absorbs the reverse turn-off voltage generated during the turn-off process of the switch unit 212, and the protection unit 213 absorbs the high-frequency ringing signal generated during the turn-off process of the switch unit 212, thereby reducing interference, improving the control accuracy of voltage adjustment, and thus improving the stability of the output voltage.

[0091] Please refer to the following: Figures 5-7 ,like Figure 5 As shown, the first voltage divider unit 311 includes resistors R43, R42, R22, R21, R23 and VR1; the first buffer unit 312 includes a first follower U5 and a first capacitor C33; the first superposition unit 321 includes resistors R20 and R26; and the first comparison unit 322 includes a first comparator U6, resistor R39 and resistor R41.

[0092] Resistors R43 to R21 are connected in series. One end of resistor R43 is connected to the first output terminal of voltage output circuit 20. One end of resistor R21 is connected to one end of resistor 23, one end of resistor R20, one end of first capacitor C33, and the non-inverting input terminal of first follower U5. The other end of resistor R23 is connected to one end of resistor VR1, and the other end of resistor VR1 is grounded. The other end of first capacitor C33 is grounded. The inverting input terminal of first follower U5 is connected to the output terminal of first follower U5 and one end of resistor R20.

[0093] In some embodiments, the first voltage divider unit 311 further includes capacitors C31 and C32. One end of capacitor C31 is connected to one end of resistor R42 and one end of resistor R22, respectively, and the other end of capacitor C31 is connected to the non-inverting input terminal of the first follower U5. One end of capacitor C32 is connected to one end of resistor R43, and the other end of capacitor C32 is connected to one end of capacitor C31, one end of resistor R42, and one end of resistor R22, respectively.

[0094] The other end of resistor R20 is connected to one end of resistor R26 and the inverting input of the first comparator U6. The non-inverting input of the first comparator U6 is grounded. The output of the first comparator U6 is connected to one end of resistor R39. The other end of resistor R39 is connected to one end of resistor R41 and the first input of the selection control circuit. The other end of resistor R41 is grounded.

[0095] The first comparison unit 322 also includes resistors R17 to R19, and capacitors C29 and C30. Resistor R17 is connected in parallel between the inverting input terminal and the output terminal of the first comparator U6. One end of resistor R18 is connected to the output terminal of the first comparator U6 and one end of resistor R19. The other end of resistor R18 is connected to one end of capacitor C29, the other end of resistor R19 and one end of capacitor C30. The other end of capacitor C29 is connected to the other end of capacitor C30 and the inverting input terminal of the first comparator U6.

[0096] The second voltage divider unit 411 includes resistors R45, R44, R35, R34, R37 and a second variable resistor VR2; the inverting unit 421 includes resistors R33, R31 and a second comparator U8; the second superposition unit 422 includes resistors R36 and R40; the second comparison unit 423 includes a third comparator U9, resistors R46 and R47; and the second buffer unit 412 includes a second follower U10 and a second capacitor C38.

[0097] Resistors R45, R44, R35, and R34 are connected in series. One end of resistor R45 is connected to the second output terminal of voltage output circuit 20. One end of resistor R34, one end of resistor R37, and one end of second capacitor C38 are connected to the non-inverting input terminal of second follower U10. The other end of resistor R37 is connected to one end of second variable resistor VR2. The other end of second variable resistor VR2 is grounded, and the other end of second capacitor C38 is grounded.

[0098] The inverting input of the second follower U10 is connected to its output. The output of the second follower U10 is connected to one end of resistor R33. The other end of resistor R33 is connected to one end of resistor R31 and the inverting input of the second comparator U8. The non-inverting input of the second comparator U8 is grounded. The other end of resistor R31 is connected to the output of the second comparator U8 and one end of resistor R36.

[0099] The other end of resistor R36 is connected to one end of resistor R40 and the inverting input of the third comparator U9. The non-inverting input of the third comparator U9 is grounded. The output of the third comparator U9 is connected to one end of resistor R46. The other end of resistor R46 is connected to one end of resistor R47 and the second input of the selection control circuit.

[0100] In some embodiments, the second voltage divider unit 411 further includes capacitors C36 and C37. One end of capacitor C36 is connected to one end of resistor R35 and one end of resistor R44, respectively, and the other end of capacitor C36 is connected to the non-inverting input terminal of the second follower U10. One end of capacitor C37 is connected to one end of resistor R45, and the other end of capacitor C37 is connected to one end of capacitor C36, one end of resistor R35, and one end of resistor R44, respectively.

[0101] The second comparison unit 423 also includes resistors R29 to R32, and capacitors C34 and C35. Resistor R29 is connected in parallel between the inverting input terminal and the output terminal of the second comparator U9. One end of resistor R30 is connected to the output terminal of the second comparator U9 and one end of resistor R32. The other end of resistor R30 is connected to one end of capacitor C34, the other end of resistor R32, one end of capacitor C34, and one end of capacitor C35. The other end of capacitor C34 is connected to the other end of capacitor C35 and the inverting input terminal of the second comparator U9.

[0102] The reference circuit 10 includes resistors R27, R25, and R24, and a fourth comparator U7. One end of resistor R27 is connected to one end of resistor R25 and is used to input the set voltage VSET. The other end of resistor R27 is grounded. The other end of resistor R25 is connected to one end of resistor R24 ​​and the inverting input of the fourth comparator U7. The non-inverting input of the fourth comparator U7 is grounded. The other end of resistor R24 ​​is connected to the output of the fourth comparator U7, resistor R26, and resistor R40. The output of the fourth comparator U7 is used to output the reference voltage -VSET.

[0103] like Figure 6 As shown, the selection control circuit 50 includes a first diode D4 and a second diode D5. The anode of the first diode D4 is connected to resistors R39 and R41, respectively. The anode of the second diode D5 is connected to resistors R46 and R47, respectively. The cathodes of the first diode D4 and the second diode D5 are connected to the input terminal of the drive unit 211.

[0104] The preset output voltage, set voltage, and reference voltage can be set as needed. In this embodiment, the preset output voltage is 1500V, the set voltage VSET is +10V, and the reference voltage -VSET is -10V.

[0105] The first variable resistor VR1 can adjust the ratio of the positive output voltage +VOUT to the first sampling voltage. For example, if the positive output voltage is 1400V and the voltage division ratio is 1:150, then the first voltage division is +9.3V. This voltage division ratio can also be adjusted according to the actual situation.

[0106] The first voltage divider then outputs a first sampling voltage via the first follower U5, which is +9.3V. If the set voltage VSET is +10V and the reference voltage -VSET is -10V, then there is a first total voltage between resistors R20 and R26 (point N1), which is -0.7V. Since this first total voltage is not equal to zero potential, the first comparator U6 outputs a first adjustment signal +Verror to the anode of the first diode D4, resulting in a positive voltage. For example, if the power supply to the first comparator U6 is 15V, then the first adjustment signal +Verror will be a +15V voltage signal. Optionally, the magnitude of the first adjustment signal +Verror can be set proportionally to the voltage at point N1, meaning the magnitude of the first adjustment signal +Verror can be adjusted according to different proportions based on the voltage at point N1.

[0107] The first adjustment signal +Verror is output to the input terminal of the drive unit 211 via the first diode D4. When the drive unit 211 receives the first adjustment signal +Verror, it outputs the corresponding control signal to control the switching unit 212 to turn on and off, thereby increasing the positive output voltage until the positive output voltage is adjusted to the preset output voltage.

[0108] Similarly, the second variable resistor VR2 can adjust the ratio between the negative output voltage -VOUT and the second sampling voltage. For example, if the negative output voltage -VOUT is -1400V, and the voltage division ratio is 1:150, then the second voltage division is -9.3V. This voltage division ratio can also be adjusted according to the actual situation.

[0109] The second voltage divider outputs a second sampled voltage, -9.3V, after passing through the second follower U10. This second sampled voltage is then inverted by the second comparator U8, outputting an inverted second sampled voltage, which is +9.3V.

[0110] If the set voltage VSET is +10V and the reference voltage -VSET is -10V, then a second total voltage exists between resistors R36 and R40 (point N2), which is -0.7V. Since this second total voltage is not equal to zero potential, the third comparator U9 outputs a second adjustment signal -Verror to the anode of the second diode D5, resulting in a negative voltage. For example, if the power supply to the third comparator U9 is 15V, then the second adjustment signal -Verror will be a +14V voltage signal. Similarly, the magnitude of the second adjustment signal -Verror can be set proportionally to the voltage at point N2; that is, the magnitude of the second adjustment signal -Verror can be adjusted according to different proportions based on the voltage at point N2.

[0111] The second adjustment signal -Verror is output to the input terminal of the drive unit 211 via the second diode D5. When the drive unit 211 receives the second adjustment signal -Verror, it outputs the corresponding control signal to control the switching unit 212 to turn on and off, thereby reducing the negative output voltage -VOUT until the negative output voltage -VOUT is adjusted to the negative preset output voltage.

[0112] If the first adjustment signal +Verror is output to the anode of the first diode D4 and the second adjustment signal -Verror is output to the anode of the second diode D5, then only one adjustment signal is valid. For example, if the positive output voltage VOUT is 1400V, the negative output voltage -VOUT is -1300V, and the preset output voltage is ±1500V, the first adjustment signal +Verror is a positive signal, and the second adjustment signal -Verror is a positive signal. If the voltage of the first adjustment signal +Verror is less than the voltage of the second adjustment signal -Verror, then the second diode D5 is turned on. The drive unit 211 receives the second adjustment signal -Verror and adjusts the negative output voltage until the negative output voltage is adjusted to the negative preset output voltage.

[0113] For example, if the positive output voltage is 1400V, the negative output voltage -VOUT is -1450V, the preset output voltage is ±1500V, the first adjustment signal +Verror is a positive signal, the second adjustment signal -Verror is a positive signal, if the voltage of the first adjustment signal +Verror is greater than the voltage of the second adjustment signal -Verror, then the first diode D4 is turned on, the drive unit 211 receives the first adjustment signal +Verror, and then adjusts the positive output voltage +VOUT until the positive output voltage +VOUT is adjusted to the positive preset output voltage.

[0114] like Figure 6 and Figure 7 As shown, the driving unit 211 includes a driving chip U3 and a driving chip U1. The cathodes of the first diode D4 and the second diode D5 are connected to the +ERROR pin of the driving chip U3. The OUTA pin of the driving chip U3 is connected to the INA pin of the driving chip U1. The OUTB pin of the driving chip U3 is connected to the INB pin of the driving chip U1. The OUTA pin of the driving chip U1 is connected to the gate of the MOSFET Q1 via resistor R2. The OUTB pin of the driving chip U1 is connected to the gate of the MOSFET Q2 via resistor R4.

[0115] The source of MOSFET Q1 is grounded, and the drain of MOSFET Q1 is connected to both the absorption unit 214 and the protection unit 213. Specifically, the absorption unit 214 includes a resistor R14, a capacitor C24, and a diode D7. The protection unit 213 includes an inductor T2 and a magnetic ring. The anode of diode D7 is connected to the drain of MOSFET Q1 and one end of the primary winding of inductor T2. The cathode of diode D7 is connected to one end of resistor R14 and one end of capacitor C24. The other ends of resistor R14 and capacitor C24 are connected to a +24V power supply.

[0116] A magnetic ring is fitted onto the other end of the primary coil of inductor T2, and the other end of the primary coil of inductor T2 is also connected to one end of the primary side of the energy conversion circuit. The other end of the primary side of the energy conversion circuit is connected to one end of the secondary coil of inductor T2, and the magnetic ring is fitted onto one end of the secondary coil of inductor T2. The other end of the secondary coil of inductor T2 is connected to the drain of MOSFET Q2.

[0117] The absorption unit 214 also includes a resistor R15, a capacitor C25, and a diode D9. The anode of the diode D9 is connected to the drain of the MOSFET Q2, and the cathode of the diode D9 is connected to one end of the resistor R15 and one end of the capacitor C25. The other end of the resistor R15 and the other end of the capacitor C25 are connected to the +24V power supply.

[0118] When driver chip U3 receives the target adjustment signal, it forwards the target adjustment signal to driver chip U1. Driver chip U1 generates a corresponding control signal based on the target adjustment signal. The control signal is a PWM signal, which controls the turn-on and turn-off of MOSFETs Q1 and Q2 respectively. The duty cycle of the PWM signal determines the turn-on and turn-off time of MOSFETs Q1 and Q2, thereby determining the conversion of the DC signal output from the input power supply VIN by the energy conversion circuit.

[0119] The energy conversion circuit includes a transformer T1. The DC signal output from the input power supply VIN is a +24V signal. The +24V signal is filtered by capacitors C5, C20, C21, C3 and C4 before being output to the primary side of transformer T1.

[0120] The secondary side of transformer T1 is connected to a polarity reversal circuit, which includes capacitor C28, a first branch, and a second branch. The first branch includes capacitor C1, Zener diodes D1A, D1B, D2A, and D2B, capacitor C2, bidirectional diode D1, capacitor C39, inductor L1, and capacitor C40. Capacitor C28 is connected in parallel across the secondary winding of transformer T1. One end of capacitor C1 is connected to one end of the secondary winding of transformer T1, and the other end of capacitor C1 is connected to the anode of Zener diode D1B and the cathode of Zener diode D2A. The cathode of Zener diode D1B is connected to the anode of Zener diode D1A. The cathode of Zener diode D1A is connected to one end of capacitor C2 and one end of inductor L1. The other end of inductor L1 is connected to one end of capacitor C40 and is used to output a positive output voltage +VOUT. The anode of Zener diode D2A is connected to the cathode of Zener diode D2B. The anode of Zener diode D2B, the other end of capacitor C2, and the other end of capacitor C40 are all grounded to HGND. Capacitor C39 is connected in parallel with inductor L1. Bidirectional diode D1 is connected in parallel with inductor L1.

[0121] Similarly, the second branch includes capacitor C8, Zener diodes D4A, D4B, D5A, D5B, capacitor C6, bidirectional diode D2, capacitor C27, inductor L2, and capacitor C26. One end of capacitor C8 is connected to one end of the secondary winding of transformer T1. The other end of capacitor C8 is connected to the anode of Zener diode D4B and the cathode of Zener diode D5A. The cathode of Zener diode D4B is connected to the anode of Zener diode D4A. The anode of Zener diode D5A is connected to the cathode of Zener diode D5B. The anode of Zener diode D5B is connected to one end of capacitor C6 and one end of inductor L2. The other end of inductor L2 is connected to one end of capacitor C26 and is used to output a negative output voltage -VOUT. The cathode of Zener diode D4A, the other end of capacitor C6, and the other end of capacitor C26 are all grounded to HGND. Capacitor C27 is connected in parallel with inductor L2, and bidirectional diode D2 is connected in parallel with inductor L2.

[0122] During the turn-on and turn-off process of MOSFETs Q1 and Q2, transformer T1 converts the DC signal (such as a +24V DC signal) output from the input power supply VIN into an AC signal. This AC signal outputs a positive output voltage +VOUT (e.g., +1500V) through the first branch and a negative output voltage -VOUT (e.g., -1500V) through the second branch.

[0123] It should be noted that the positive output voltage +VOUT and the negative output voltage -VOUT can be determined by the set voltage VSET and the resistance value of the voltage divider resistor in the voltage divider unit (i.e., the scaling ratio). With the resistance value unchanged, the amplitude of the positive output voltage +VOUT and the negative output voltage -VOUT can be adjusted by adjusting the set voltage VSET. For example, the positive output voltage +VOUT can be adjusted to +2000V and the negative output voltage -VOUT can be adjusted to -2000V.

[0124] During the turn-off process of MOSFET Q1, both MOSFETs Q1 and Q2 generate high reverse turn-off voltages and high-frequency ringing signals. Capacitor C24, resistor R14, and diode D7 absorb the reverse turn-off voltage, reducing it and preventing damage to MOSFET Q1. Inductor T2 and the magnetic ring absorb the energy of the high-frequency ringing signal, thus reducing its intensity. Similarly, capacitor C25, resistor R15, and diode D9 absorb the reverse turn-off voltage generated by MOSFET Q2, reducing it and preventing damage to MOSFET Q2. Inductor T2 and the magnetic ring absorb the energy of the high-frequency ringing signal, thus reducing its intensity.

[0125] In summary, this voltage control circuit achieves precise control of the positive and negative output voltages through closed-loop control of sampling, comparison, and adjustment. This avoids the influence of output voltage fluctuations of the bipolar electrostatic chuck on the adsorption state, improves the stability of the positive and negative output voltages, and thus enhances the adsorption effect of the bipolar electrostatic chuck.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A voltage control circuit for a bipolar electrostatic chuck, characterized in that, The voltage control circuit includes: a reference circuit, a voltage output circuit, a positive sampling adjustment circuit, a negative sampling adjustment circuit, and a selection control circuit; The input terminal of the reference circuit is used to connect to a set voltage, and the output terminal of the reference circuit is connected to the second input terminal of the positive sampling adjustment circuit and the second input terminal of the negative sampling adjustment circuit. The reference circuit is used to convert the input set voltage into a reference voltage. The first output terminal of the voltage output circuit is used to output a positive output voltage, and the second output terminal of the voltage output circuit is used to output a negative output voltage. The first input terminal of the positive sampling adjustment circuit is connected to the first output terminal of the voltage output circuit and is used to receive the positive output voltage of the voltage output circuit. The second input terminal of the positive sampling adjustment circuit is used to receive the reference voltage. The output terminal of the positive sampling adjustment circuit is connected to the first input terminal of the selection control circuit. The positive sampling adjustment circuit is used to sample the positive output voltage, generate a first sampling voltage, compare the first sampling voltage with the reference voltage, and generate a first adjustment signal in response to the result that the sum of the first sampling voltage and the reference voltage is not equal to zero. The first input terminal of the negative sampling adjustment circuit is connected to the second output terminal of the voltage output circuit for receiving the negative output voltage of the voltage output circuit. The second input terminal of the negative sampling adjustment circuit is used to receive the reference voltage. The output terminal of the negative sampling adjustment circuit is connected to the second input terminal of the selection control circuit. The negative sampling adjustment circuit is used to sample the negative output voltage, generate a second sampling voltage, compare the second sampling voltage with the reference voltage, and generate a second adjustment signal in response to the result that the sum of the second sampling voltage and the reference voltage is not equal to zero. The output terminal of the selection control circuit is connected to the input terminal of the voltage output circuit, and is used to select the first adjustment signal and the second adjustment signal to output a target adjustment signal, so that the voltage output circuit adjusts the positive output voltage or the negative output voltage based on the target adjustment signal, wherein the target adjustment signal is the first adjustment signal or the second adjustment signal; The selection control circuit includes a first diode and a second diode; The anode of the first diode is connected to the output terminal of the positive sampling adjustment circuit, the anode of the second diode is connected to the output terminal of the negative sampling adjustment circuit, and the cathodes of the first diode and the second diode are connected together to the input terminal of the voltage output circuit.

2. The voltage control circuit for the bipolar electrostatic chuck according to claim 1, characterized in that, The positive sampling adjustment circuit includes a first sampling unit and a positive feedback adjustment unit; The first terminal of the first sampling unit is connected to the first output terminal of the voltage output circuit, the second terminal of the first sampling unit is grounded, and the third terminal of the first sampling unit is connected to the first input terminal of the positive feedback adjustment unit. The first sampling unit is used to sample the positive output voltage and generate a first sampling voltage. The second input terminal of the positive feedback adjustment unit is used to connect to the reference voltage, and the output terminal of the positive feedback adjustment unit is connected to the first input terminal of the selection control circuit. The positive feedback adjustment unit is used to compare the first sampled voltage with the reference voltage, and in response to the result that the sum of the first sampled voltage and the reference voltage is not equal to zero, outputs the first adjustment signal.

3. The voltage control circuit according to claim 2, characterized in that, The positive feedback adjustment unit includes a first superposition unit and a first comparison unit; The first end of the first superposition unit is connected to the third end of the first sampling unit, the second end of the first superposition unit is used to connect to the reference voltage, the third end of the first superposition unit is connected to the first input end of the first comparison unit, and the first superposition unit is used to superimpose the first sampled voltage and the reference voltage to generate a first total voltage. The second input terminal of the first comparison unit is grounded, and the output terminal of the first comparison unit is connected to the first input terminal of the selection control circuit. The first comparison unit is used to compare the first total voltage and the zero potential, and outputs the first adjustment signal in response to the result that the first total voltage and the zero potential are not equal.

4. The voltage control circuit according to claim 1, characterized in that, The negative sampling adjustment circuit includes a second sampling unit and a negative feedback adjustment unit; The first terminal of the second sampling unit is connected to the second output terminal of the voltage output circuit, the second terminal of the second sampling unit is grounded, and the third terminal of the second sampling unit is connected to the first input terminal of the negative feedback adjustment unit. The second sampling unit is used to sample the negative output voltage and generate a second sampling voltage. The second input terminal of the negative feedback adjustment unit is used to connect to the reference voltage, and the output terminal of the negative feedback adjustment unit is connected to the second input terminal of the selection control circuit. The negative feedback adjustment unit is used to compare the second sampled voltage with the reference voltage, and in response to the result that the sum of the second sampled voltage and the reference voltage is not equal to zero, outputs the second adjustment signal.

5. The voltage control circuit according to claim 4, characterized in that, The negative feedback adjustment unit includes a reverse unit, a second superposition unit, and a second comparison unit; The negative input terminal of the inverting unit is connected to the third terminal of the second sampling unit, the positive input terminal of the inverting unit is grounded, and the output terminal of the inverting unit is connected to the first terminal of the second superposition unit. The inverting unit is used to invert the second sampling voltage to generate the inverted second sampling voltage. The second end of the second superposition unit is used to connect to the reference voltage, and the third end of the second superposition unit is connected to the first input end of the second comparison unit. The second superposition unit is used to superimpose the inverted second sampled voltage with the reference voltage to generate a second total voltage. The second input terminal of the second comparison unit is grounded, and the output terminal of the second comparison unit is connected to the second input terminal of the selection control circuit. The second comparison unit is used to compare the second total voltage and the zero potential, and outputs the second adjustment signal in response to the result that the second total voltage and the zero potential are not equal.

6. The voltage control circuit according to claim 1, characterized in that, The voltage output circuit includes a driving circuit and an output circuit; The input terminal of the driving circuit is connected to the output terminal of the selection control circuit, the output terminal of the driving circuit is connected to the input terminal of the output circuit, the first output terminal of the output circuit is connected to the first input terminal of the positive sampling adjustment circuit, and the second output terminal of the output circuit is connected to the first input terminal of the negative sampling adjustment circuit. The driving circuit is used to adjust the positive or negative output voltage of the output circuit according to the target adjustment signal.

7. The voltage control circuit according to claim 6, characterized in that, The driving circuit includes a driving unit, a switching unit, a protection unit, and an absorption unit; The input terminal of the driving unit is connected to the output terminal of the selection control circuit, and the output terminal of the driving unit is connected to the control terminal of the switching unit. The driving unit is used to drive the switching unit to turn on and off according to the target adjustment signal, so as to adjust the positive output voltage or negative output voltage of the output circuit. The absorption unit is connected to the switching unit and is used to absorb the reverse turn-off voltage generated by the switching unit during the turn-off process. The protection unit is connected to the switching unit and is used to absorb the high-frequency ringing signal generated by the switching unit during the turn-off process.

8. The voltage control circuit according to claim 7, characterized in that, The output circuit includes an energy conversion unit and a polarity conversion unit; The primary side of the energy conversion unit is connected to the switching unit and the input power supply respectively, and the secondary side of the energy conversion unit is connected to the polarity conversion unit. The energy conversion unit is used to convert the DC signal output by the input power supply into an AC signal during the switching unit's on and off process. The polarity conversion unit is used to output a positive output voltage and a negative output voltage based on the AC signal.

9. A voltage control system for a bipolar electrostatic chuck, characterized in that, The voltage control system includes a bipolar electrostatic chuck and a voltage control circuit as described in any one of claims 1-8.

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