Electrostatic chuck and electrostatic chuck control method

Abstract

The application relates to the technical field of semiconductors, and provides an electrostatic chuck and an electrostatic chuck control method. The electrostatic chuck comprises a chuck main body and a dielectric layer, the chuck main body is connected with the dielectric layer, one end of the chuck main body is provided with a first region, a second region, a third region and a fourth region, the second region surrounds the outer side edge of the first region, the third region surrounds the outer side edge of the second region, the fourth region surrounds the outer side edge of the third region, a first electrode unit group is arranged in the first region, a second electrode unit group is arranged in the second region, a third electrode unit group is arranged in the third region, and a fourth electrode unit group is arranged in the fourth region; and a sensor array is arranged in the chuck main body. Through the above structure, different electric fields can be generated for different sizes of wafers, and electrostatic forces of different sizes can be generated for different sizes of wafers.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an electrostatic chuck and an electrostatic chuck control method. Background Art

[0002] In the semiconductor manufacturing process, stable wafer fixation is crucial for ensuring processing accuracy and quality. The electrostatic chuck (E-Chuck), a non-mechanical fixture, holds the wafer to the chuck surface through electrostatic attraction, avoiding particle contamination and wafer damage that can occur with mechanical clamping.

[0003] Electrostatic chucks typically use a bipolar design, generating an electric field between positive and negative electrodes that induce opposite charges on the wafer surface, thereby achieving electrostatic adsorption and fixation. The electrode configuration of an electrostatic chuck is often fixed and is typically designed based on the wafer size. Common wafer diameters include 150mm, 200mm, and 300mm.

[0004] However, as technology advances, wafer sizes are becoming increasingly diverse, and traditional electrostatic chucks lack adaptability. For example, when securing a 300mm wafer, more electrodes are required to ensure a uniform electric field distribution. When securing a 200mm wafer, too many electrodes will result in an overly strong electric field or energy waste. Large wafers require higher voltages to generate sufficient electrostatic force, but this also increases the risk of dielectric breakdown or arc discharge between electrodes. If dielectric breakdown or arc discharge occurs, it will greatly affect the lifespan and reliability of the chuck. In existing technologies, switching wafer sizes often requires replacing the chuck and adjusting related hardware, increasing equipment cost and operational complexity. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to provide an electrostatic chuck and an electrostatic chuck control method. By distributing electrodes in different regions, the present invention enables flexible adaptation to wafers of varying sizes. A sensor array and a forced discharge switch are used to improve the stability and reliability of the chuck when adhering to various wafers, neutralize residual charge, and thus extend the life of the electrostatic chuck. The present invention aims to address the technical problems of prior art electrostatic chucks, which have the difficulty of adapting to a variety of wafer sizes and the risk of dielectric breakdown or arc discharge between electrodes.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] An electrostatic chuck comprises a chuck body and a dielectric layer, wherein one side of the chuck body is connected to the dielectric layer, and a first region, a second region, a third region, and a fourth region are arranged at one end of the chuck body facing the dielectric layer, the second region is arranged around the outer edge of the first region, the third region is arranged around the outer edge of the second region, and the fourth region is arranged around the outer edge of the third region; a first electrode unit group is arranged in the first region, a second electrode unit group is arranged in the second region, a third electrode unit group is arranged in the third region, and a fourth electrode unit group is arranged in the fourth region; the first electrode unit group, the second electrode unit group, the third electrode unit group, and the fourth electrode unit group are all electrically connected to a power supply and a forced discharge switch; a sensor array is arranged in the end of the chuck body facing away from the dielectric layer, and the sensor array is used to monitor whether the electric field on the dielectric layer is uniform.

[0008] Compared with the prior art, the beneficial effects of the present invention are: by setting the first area, the second area, the third area and the fourth area, and making multiple areas surround layer by layer to adapt to various wafer sizes, the electrode unit group is set for each area in a targeted manner, which is beneficial to generate different electric fields for wafers of different sizes, and generate electrostatic forces of adapted sizes for wafers of different sizes to form a stable adsorption and fixation of the wafers; by setting the forced discharge switch, it is beneficial to release residual charges. When a larger wafer needs to be adsorbed, even if a larger voltage is provided to generate a larger electrostatic force, the residual charges can be released in time to prevent the dielectric layer from being punctured or arc discharge between electrodes; by setting the sensor array, whether the electric field is uniform when adsorbing the wafer is monitored, which is beneficial to timely make voltage adjustments to ensure that the adsorption of the wafer is sufficiently stable.

[0009] Furthermore, the first electrode unit group includes a first positive electrode unit and a first negative electrode unit, the second electrode unit group includes a second positive electrode unit and a second negative electrode unit, the third electrode unit group includes two third positive electrode units and two third negative electrode units, and the fourth electrode unit group includes three fourth positive electrode units and three fourth negative electrode units.

[0010] Furthermore, the first area is circular, and the second area, the third area, and the fourth area are annular shapes concentric with the first area.

[0011] Furthermore, one end of the forced discharge switch is connected to the ground end, the other end of the forced discharge switch is connected to the output relay, the end of the output relay facing away from the forced discharge switch is connected to the radio frequency filter, the end of the radio frequency filter facing away from the output relay is connected to the output end, and the output end is used to connect the first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group.

[0012] Furthermore, one end of the power supply is connected to the ground end, and the other end of the power supply is connected to an end of the forced discharge switch away from the ground end, and the power supply is used to apply a forward voltage or a reverse voltage.

[0013] Furthermore, the first positive electrode unit and the first negative electrode unit are symmetrically arranged along the center of the circle, the second positive electrode unit and the second negative electrode unit are symmetrically arranged along the center of the circle, the third positive electrode unit and the third negative electrode unit are symmetrically arranged along the center of the circle, and the fourth positive electrode unit and the fourth negative electrode unit are symmetrically arranged along the center of the circle.

[0014] Furthermore, the suction cup body includes a positive pole portion and a negative pole portion that are arranged opposite to each other, and the first positive electrode unit, the second positive electrode unit, the two third positive electrode units and the three fourth positive electrode units are all located in the positive pole portion, and the first negative electrode unit, the second negative electrode unit, the two third negative electrode units and the three fourth negative electrode units are all located in the negative pole portion.

[0015] Furthermore, the sensor array includes a first sensor group, a second sensor group, a third sensor group and a fourth sensor group, the first sensor group corresponds to the first area position, the first sensor group includes two first sensors, the second sensor group corresponds to the second area position, the second sensor group includes two second sensors, the third sensor group corresponds to the third area position, the third sensor group includes four third sensors, the fourth sensor group corresponds to the fourth area position, and the fourth sensor group includes six fourth sensors.

[0016] Furthermore, the projection of the third sensor in the third area is located between two adjacent third positive electrode units, between two adjacent third negative electrode units, or between adjacent third positive electrode units and the third negative electrode unit, and the projection of the fourth sensor in the fourth area is located between two adjacent fourth positive electrode units, between two adjacent fourth negative electrode units, or between adjacent fourth positive electrode units and the fourth negative electrode unit.

[0017] A method for controlling an electrostatic chuck, applied to the electrostatic chuck according to the above technical solution, comprises the following steps:

[0018] Placing a wafer on a surface of an electrostatic chuck, wherein the electrostatic chuck includes a chuck body and a dielectric layer connected to the chuck body, wherein the dielectric layer abuts against the wafer, and wherein the chuck body has a first region, a second region, a third region, and a fourth region disposed on one end thereof facing the dielectric layer;

[0019] selecting an adsorption electrode unit group from the first electrode unit group in the first area, the second electrode unit group in the second area, the third electrode unit group in the third area, and the fourth electrode unit group in the fourth area according to the diameter of the wafer, and turning on the adsorption electrode unit group by power to adsorb the wafer for processing;

[0020] determining whether the electric field on the dielectric layer is uniform by means of a sensor array in an end of the chuck body facing away from the dielectric layer; if the electric field on the dielectric layer is uniform, processing the wafer; and if the electric field on the dielectric layer is non-uniform, adjusting the power supply until the electric field on the dielectric layer is uniform;

[0021] After the processing is completed, the power supply is turned off and the forced discharge switch is turned on to eliminate the residual charge and separate the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the electrostatic chuck in the first embodiment of the present invention;

[0023] Figure 2 A schematic diagram of a portion of the structure of an electrostatic chuck according to a first embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the structure of the electrostatic chuck main body in the first embodiment of the present invention;

[0025] Figure 4 Schematic diagram of the power supply and forced discharge switch in the electrostatic chuck in the first embodiment of the present invention;

[0026] Description of main component symbols:

[0027] 100. Suction cup body; 101. Positive electrode portion; 102. Negative electrode portion; 110. First region; 111. First positive electrode unit; 112. First negative electrode unit; 120. Second region; 121. Second positive electrode unit; 122. Second negative electrode unit; 130. Third region; 131. Third positive electrode unit; 132. Third negative electrode unit; 140. Fourth region; 141. Fourth positive electrode unit; 142. Fourth negative electrode unit; 200. Dielectric layer; 310. Power supply; 320. Forced discharge switch; 330. Ground terminal; 340. Output relay; 350. RF filter; 360. Output terminal; 400. Sensor array; 410. First sensor; 420. Second sensor; 430. Third sensor; 440. Fourth sensor; 500. Wafer.

[0028] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] See also Figures 1 to 4The electrostatic chuck in the first embodiment of the present invention includes a chuck body 100 and a dielectric layer 200. One surface of the chuck body 100 is connected to the dielectric layer 200. A first region 110, a second region 120, a third region 130, and a fourth region 140 are provided on one end of the chuck body 100 facing the dielectric layer 200. The second region 120 is provided around the outer edge of the first region 110, the third region 130 is provided around the outer edge of the second region 120, and the fourth region 140 is provided around the outer edge of the third region 130. The first region 110 is circular, and the second region 120, the third region 130, and the fourth region 140 are annular shapes concentric with the first region 110. A first electrode unit group is provided in the first region 110, a second electrode unit group is provided in the second region 120, a third electrode unit group is provided in the third region 130, and a fourth electrode unit group is provided in the fourth region 140. Preferably, the diameter of the first area 110 is adapted to a wafer with a diameter of 150 mm, the outer diameter of the second area 120 is adapted to a wafer with a diameter of 200 mm, the outer diameter of the third area 130 is adapted to a wafer with a diameter of 300 mm, and the outer diameter of the fourth area 140 is adapted to a wafer with a diameter of 450 mm. The suction cup body 100 is made of a ceramic material with high thermal conductivity, specifically, made of aluminum nitride, to provide good thermal conductivity and electrical insulation properties. The first electrode unit group can be used to fix a wafer with a diameter of 150 mm, the second electrode unit group and the first electrode unit group can be used together to fix a wafer with a diameter of 200 mm, the third electrode unit group, the second electrode unit group and The first electrode unit group can be used together to fix a wafer with a diameter of 300 mm. The fourth electrode unit group, the third electrode unit group, the second electrode unit group and the first electrode unit group can be used together to fix a wafer with a diameter of 450 mm. The dielectric layer 200 is made of a high dielectric constant material, specifically, zirconium oxide. The dielectric layer 200 is used to enhance the electric field strength and prevent breakdown between electrodes. Nano-scale grooves are designed on the surface of the dielectric layer 200 to reduce the contact area between the wafer and the electrostatic suction cup and reduce the accumulation of residual charge. The diameter of the suction cup body 100 is 500 mm, the thickness of the suction cup body 100 is 10 mm, and the thickness of the dielectric layer 200 is 0.5 mm.

[0033] The first electrode unit group includes a first positive electrode unit 111 and a first negative electrode unit 112, the second electrode unit group includes a second positive electrode unit 121 and a second negative electrode unit 122, the third electrode unit group includes two third positive electrode units 131 and two third negative electrode units 132, the fourth electrode unit group includes three fourth positive electrode units 141 and three fourth negative electrode units 142, the first positive electrode unit 111 and the first negative electrode unit 112 are symmetrically arranged along the center of the circle, the second positive electrode unit 121 and the second negative electrode unit 122 are symmetrically arranged along the center of the circle, the third positive electrode unit 131 and The third negative electrode unit 132 is symmetrically arranged along the center of the circle, and the fourth positive electrode unit 141 and the fourth negative electrode unit 142 are symmetrically arranged along the center of the circle. The suction cup body 100 includes a positive electrode portion 101 and a negative electrode portion 102 that are relatively arranged. The first positive electrode unit 111, the second positive electrode unit 121, the two third positive electrode units 131 and the three fourth positive electrode units 141 are all located in the positive electrode portion 101, and the first negative electrode unit 112, the second negative electrode unit 122, the two third negative electrode units 132 and the three fourth negative electrode units 142 are all located in the negative electrode portion 102. Preferably, a voltage of 500V~1000V is applied to the positive electrode unit and the negative electrode unit to form an electric field between the positive electrode part 101 and the negative electrode part 102, inducing opposite charges on the surface of the wafer, thereby adsorbing the wafer on the surface of the suction cup. Specifically, for example, when processing a wafer with a diameter of 300mm, a voltage of 800V is applied to the electrode units in the first area 110, the second area 120 and the third area 130 to form an adsorption force of 100kPa on the wafer. It can be understood that the symmetry of the positive electrode unit and the negative electrode unit relative to the center of the circle is beneficial to generating a uniform adsorption force. Starting the electrode units in different areas can make the electrostatic suction cup adapt to wafers of various sizes. The number of electrodes is set for each area according to the size of the wafer, and voltages of different sizes are applied, which is beneficial to generating electrostatic forces adapted to the size of the wafer, and wafers of different sizes can be stably adsorbed and fixed.

[0034] The first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group are electrically connected to a power supply 310 and a forced discharge switch 320, one end of the forced discharge switch 320 is connected to a ground terminal 330, the other end of the forced discharge switch 320 is connected to an output relay 340, the output relay 340 away from the one end of the forced discharge switch 320 is connected to a radio frequency filter 350, the radio frequency filter 350 away from the one end of the output relay 340 is connected to an output terminal 360, the output terminal 360 is used to connect the first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group, one end of the power supply 320 is connected to the ground terminal 330, the other end of the power supply 310 is connected to the other end of the forced discharge switch 320 away from the ground terminal 330, and the power supply 310 is used to apply a forward voltage or a reverse voltage. Preferably, the forward voltage of the power supply 310 is 500V-1000V, and the reverse voltage is specifically a reverse pulse voltage, the frequency of the reverse pulse voltage is 50Hz, the size of the reverse pulse voltage is 200V, the reverse voltage is beneficial to quickly eliminate residual charges, the forced discharge switch 320 can force the charges to be grounded, which is beneficial to quickly eliminate the residual charges on the electrostatic chuck and the wafer, and can ensure the safety of the operator, can prevent the wafer from being difficult to separate from the electrostatic chuck due to the influence of residual charges, the output relay 340 is used to cut off or connect the voltage output between the power supply 310 and the chuck electrode, when the output relay 340 is opened, it can prevent the electrostatic chuck from voltage drop when conveying the wafer to the next process, which is beneficial to ensure the stability of the wafer fixation, the radio frequency filter 350 is used to filter high-frequency noise, ensure the stability and purity of the output voltage, prevent noise interference, maintain the stability of wafer fixation, and improve the accuracy of wafer processing. It can be understood that when a larger size wafer needs to be adsorbed, even if a larger voltage is provided to generate a larger electrostatic force, the phenomenon of dielectric layer breakdown or electrode arc discharge can be prevented by timely releasing residual charges.

[0035] A sensor array 400 is disposed within one end of the suction cup body 100 facing away from the dielectric layer 200. The sensor array 400 is used to monitor whether the electric field on the dielectric layer 200 is uniform. The sensor array 400 includes a first sensor group, a second sensor group, a third sensor group, and a fourth sensor group. The first sensor group corresponds to the first area 110 and includes two first sensors 410. The second sensor group corresponds to the second area 120 and includes two second sensors 420. The third sensor group corresponds to the third area 130 and includes four third sensors 430. The fourth sensor group corresponds to the position of the fourth area 140, and the fourth sensor group includes six fourth sensors 440. The projection of the third sensor 430 in the third area 130 is located between two adjacent third positive electrode units 131, between two adjacent third negative electrode units 132, or between adjacent third positive electrode units 131 and third negative electrode units 132. The projection of the fourth sensor 440 in the fourth area 140 is located between two adjacent fourth positive electrode units 141, between two adjacent fourth negative electrode units 142, or between adjacent fourth positive electrode units 141 and fourth negative electrode units 142. Preferably, the sensor array 400 is embedded in the suction cup body 100 for real-time monitoring of the electric field distribution to obtain the wafer adsorption state. The output of the power supply 310 can be adjusted according to the feedback of the sensor array 400, thereby applying a uniform and stable adsorption force to the wafer. The projection of the first sensor 410 in the first area 110 is adjacent to the first positive electrode unit 111 or the first negative electrode unit 112, and the projection of the second sensor 420 in the second area 120 is adjacent to the second positive electrode unit 121 or the second negative electrode unit 122.

[0036] A second embodiment of the present invention provides an electrostatic chuck control method, which is applied to the electrostatic chuck described in the first embodiment, comprising the following steps:

[0037] Step S10: placing a wafer on a surface of an electrostatic chuck, wherein the electrostatic chuck includes a chuck body and a dielectric layer connected to the chuck body, the dielectric layer abutting the wafer, and the chuck body having a first region, a second region, a third region, and a fourth region disposed on one end of the chuck body facing the dielectric layer;

[0038] Preferably, see Figure 1 , the wafer 500 is adsorbed on the surface of the dielectric layer 200 .

[0039] Step S20: according to the diameter of the wafer, select the adsorption electrode unit group from the first electrode unit group in the first area, the second electrode unit group in the second area, the third electrode unit group in the third area and the fourth electrode unit group in the fourth area, and turn on the adsorption electrode unit group by the power supply to adsorb the wafer for processing;

[0040] Preferably, if the diameter of the wafer 500 is 150mm, the first electrode unit group is the adsorption electrode unit group, and the first positive electrode unit group is turned on to adsorb the wafer 500; if the diameter of the wafer 500 is 200mm, the adsorption electrode unit group is composed of the first electrode unit group and the second electrode unit group; if the diameter of the wafer 500 is 300mm, the adsorption electrode unit group is composed of the first electrode unit group, the second electrode unit group and the third electrode unit group; if the diameter of the wafer 500 is 450mm, the adsorption electrode unit group is composed of the first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group.

[0041] Further, taking the wafer 500 with an adsorption diameter of 300mm as an example, the main voltage is the forward voltage, and the first positive electrode unit 111, the first negative electrode unit 112, the second positive electrode unit 121, the second negative electrode unit 122, the two third positive electrode units 131 in the third area 130 and the two third negative electrode units 132 in the third area 130 are applied with a forward voltage of 800V by the power supply 310, forming an adsorption force of 100kPa.

[0042] Step S30: determine whether the electric field on the dielectric layer is uniform through the sensor array in the end of the chuck body away from the dielectric layer, if the electric field on the dielectric layer is uniform, process the wafer, if the electric field on the dielectric layer is not uniform, adjust the power supply until the electric field on the dielectric layer is uniform;

[0043] Preferably, the electric field uniformity error is less than 5%, which is determined as uniform electric field, which is beneficial to apply stable and uniform adsorption force to the wafer 500, and ensures the accuracy of wafer processing.

[0044] Step S40: after processing, turn off the power supply and turn on the forced discharge switch to eliminate residual charge and make the wafer separate.

[0045] Preferably, turning off the power supply 310 is conducive to the rapid disappearance of the charge. In addition to turning off the power supply 310, the power supply 310 can also apply a reverse voltage. The frequency of the reverse voltage is 50Hz, the magnitude of the reverse voltage is 200V, and the detachment time of the wafer 500 is 1 second to 2 seconds. It can be understood that the method of forced discharge and applying reverse voltage can quickly eliminate residual charge, which is beneficial to the rapid and smooth detachment of the wafer 500.

[0046] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0047] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An electrostatic chuck, characterized in that: The invention comprises a suction cup body and a dielectric layer, wherein one side of the suction cup body is connected to the dielectric layer, and a first area, a second area, a third area and a fourth area are arranged at one end of the suction cup body facing the dielectric layer, the second area is arranged around the outer edge of the first area, the third area is arranged around the outer edge of the second area, and the fourth area is arranged around the outer edge of the third area. A first electrode unit group is arranged in the first area, a second electrode unit group is arranged in the second area, a third electrode unit group is arranged in the third area, and a fourth electrode unit group is arranged in the fourth area. The first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group are all electrically connected to a power supply and a forced discharge switch. A sensor array is arranged in the end of the suction cup body facing away from the dielectric layer, and the sensor array is used to monitor whether the electric field on the dielectric layer is uniform. The first electrode unit group includes a first positive electrode unit and a first negative electrode unit, the second electrode unit group includes a second positive electrode unit and a second negative electrode unit, and the third electrode unit group includes two third positive electrode units and two third negative electrode units. The fourth electrode unit group includes three fourth positive electrode units and three fourth negative electrode units. The sensor array includes a first sensor group, a second sensor group, a third sensor group, and a fourth sensor group. The first sensor group corresponds to the first area. The first sensor group includes two first sensors. The second sensor group corresponds to the second area. The second sensor group includes two second sensors. The third sensor group corresponds to the third area. The third sensor group includes four third sensors. The fourth sensor group corresponds to the fourth area. The fourth sensor group includes six fourth sensors. The projection of the third sensor in the third area is located between two adjacent third positive electrode units, between two adjacent third negative electrode units, or between the adjacent third positive electrode unit and the third negative electrode unit. The projection of the fourth sensor in the fourth area is located between two adjacent fourth positive electrode units, between two adjacent fourth negative electrode units, or between the adjacent fourth positive electrode unit and the fourth negative electrode unit.

2. The electrostatic chuck according to claim 1, wherein The first area is circular, and the second area, the third area, and the fourth area are annular shapes concentric with the first area.

3. The electrostatic chuck according to claim 1, wherein One end of the forced discharge switch is connected to the ground end, the other end of the forced discharge switch is connected to the output relay, the end of the output relay facing away from the forced discharge switch is connected to the radio frequency filter, the end of the radio frequency filter facing away from the output relay is connected to the output end, and the output end is used to connect the first electrode unit group, the second electrode unit group, the third electrode unit group and the fourth electrode unit group.

4. The electrostatic chuck according to claim 3, wherein: One end of the power supply is connected to the ground end, and the other end of the power supply is connected to an end of the forced discharge switch away from the ground end. The power supply is used to apply a forward voltage or a reverse voltage.

5. The electrostatic chuck according to claim 2, wherein: The first positive electrode unit and the first negative electrode unit are symmetrically arranged along the center of the circle, the second positive electrode unit and the second negative electrode unit are symmetrically arranged along the center of the circle, the third positive electrode unit and the third negative electrode unit are symmetrically arranged along the center of the circle, and the fourth positive electrode unit and the fourth negative electrode unit are symmetrically arranged along the center of the circle.

6. The electrostatic chuck according to claim 1, wherein: The suction cup body includes a positive pole portion and a negative pole portion arranged opposite to each other, the first positive electrode unit, the second positive electrode unit, the two third positive electrode units and the three fourth positive electrode units are all located in the positive pole portion, and the first negative electrode unit, the second negative electrode unit, the two third negative electrode units and the three fourth negative electrode units are all located in the negative pole portion.

7. A method for controlling an electrostatic chuck, applied to the electrostatic chuck according to any one of claims 1 to 6, characterized in that: The following steps are involved: Placing a wafer on a surface of an electrostatic chuck, wherein the electrostatic chuck includes a chuck body and a dielectric layer connected to the chuck body, wherein the dielectric layer abuts against the wafer, and wherein the chuck body has a first region, a second region, a third region, and a fourth region disposed on one end thereof facing the dielectric layer; selecting an adsorption electrode unit group from the first electrode unit group in the first area, the second electrode unit group in the second area, the third electrode unit group in the third area, and the fourth electrode unit group in the fourth area according to the diameter of the wafer, and turning on the adsorption electrode unit group by power to adsorb the wafer for processing; determining whether the electric field on the dielectric layer is uniform by means of a sensor array in an end of the chuck body facing away from the dielectric layer; if the electric field on the dielectric layer is uniform, processing the wafer; and if the electric field on the dielectric layer is non-uniform, adjusting the power supply until the electric field on the dielectric layer is uniform; After the processing is completed, the power supply is turned off and the forced discharge switch is turned on to eliminate the residual charge and separate the wafer.

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