Chip falling detection method and device for polishing head

Abstract

The embodiment of the invention discloses a wafer falling detection method and device of a polishing head, the wafer falling detection of the polishing head can comprise a light ray detection mechanism and a controller, the light ray detection mechanism is used for collecting surface light ray information of the side, away from a rotating shaft, of the polishing head in the process that the polishing head moves a wafer to make contact with a polishing pad, and the controller is used for controlling the surface light ray information of the side, away from the rotating shaft, of the polishing head; the controller is used for determining the wafer adsorption state of the polishing head according to the surface light information.

Description

Technical Field

[0001] The disclosed embodiments relate to the field of semiconductor manufacturing technology, and more particularly to a method and device for detecting wafer drop of a polishing head. Background Art

[0002] In the field of semiconductor manufacturing, chemical mechanical polishing (CMP) technology is a key process to achieve wafer surface flatness. CMP technology combines chemical corrosion and mechanical friction to polish the wafer surface to achieve the required flatness.

[0003] Traditional polishing equipment lacks effective detection means when loading wafers. There is only a sensor installed inside the loading tray to detect whether the wafer has fallen off the loading tray. However, when the polishing head is loading the wafer and transferring the wafer to contact the polishing pad, if there is a deviation in the wafer loading position or an abnormality in the adsorption pad, the wafer may fall after loading. Since the polishing head itself has no detection device, it cannot detect the wafer falling in time, which may cause the equipment to grind in vain, affect the life of the adsorption pad and polishing pad, and even cause equipment damage and production capacity loss. Summary of the invention

[0004] In view of this, the embodiments of the present disclosure are intended to provide a method and device for detecting wafer drop of a polishing head, which can solve the technical problem in the prior art that wafer drop detection of a polishing head cannot be performed.

[0005] The technical solution of the embodiment of the present disclosure is implemented as follows: In a first aspect, an embodiment of the present disclosure provides a wafer drop detection device for a polishing head, comprising: A light detection mechanism, used to collect surface light information on the side of the polishing head away from the rotating shaft when the polishing head moves the wafer to contact the polishing pad; The controller is used to determine the adsorption state of the polishing head to the wafer according to the surface light information.

[0006] In some examples, the light detection mechanism includes a light sensor, which is disposed on a side of the polishing head away from the rotating shaft, and whose orthographic projection along the central axis of the rotating shaft does not overlap with the polishing head.

[0007] In some examples, the polishing head includes a vacuum adsorption device; The controller is connected to the vacuum adsorption device of the polishing head and is used to control the working state of the vacuum adsorption device according to the adsorption state.

[0008] In some examples, the adsorption state includes adsorption and non-adsorption; The controller is used for controlling the vacuum adsorption device to stop working when the adsorption state is non-adsorption.

[0009] In some examples, the detection device further includes: The alarm mechanism is used to send out an alarm signal when the adsorption state is not adsorbed.

[0010] In some examples, the controller is used to determine the adsorption state based on wavelength information collected in the light information.

[0011] In some examples, the detection device further includes: a telescopic mechanism connected between the controller and the light detection mechanism, and used for moving the light detection mechanism away from the polishing pad when the distance between the polishing head and the polishing pad is less than a preset distance; The preset distance is the minimum distance at which the light collection mechanism can collect the surface light information.

[0012] In a second aspect, an embodiment of the present disclosure provides a method for detecting chip drop of a polishing head, which is applied to a controller and includes: When the polishing head moves the wafer to contact the polishing pad, obtaining surface light information of the side of the polishing head away from the rotating shaft; The adsorption state of the polishing head to the wafer is determined according to the surface light information.

[0013] In some examples, determining the adsorption state of the polishing head to the wafer according to the surface light information further includes: Obtaining the collected wavelength information in the light information and the calibrated wavelength information reflected by the wafer; When the acquisition wavelength information is different from the calibration wavelength information, it is determined that the adsorption state is not adsorbed.

[0014] In some examples, the polishing head includes a vacuum adsorption device and an alarm mechanism; the method further includes: When the adsorption state is non-adsorption, the vacuum adsorption device is controlled to stop working, and the alarm mechanism is controlled to send out an alarm signal.

[0015] The disclosed embodiment provides a method and device for detecting wafer drop of a polishing head; light information on the surface of the polishing head is collected by a light detection mechanism, and a controller determines the adsorption state of the polishing head to the wafer according to the surface light information, and monitors the adsorption state of the polishing head in real time. Once wafer drop is found, the operation of the polishing head can be stopped in time, thereby avoiding equipment damage and production capacity loss caused by wafer drop, while also reducing the time and resources lost due to equipment maintenance and cleaning, and improving overall production capacity and efficiency. The device enhances the intelligence level of CMP equipment through automated light detection and control, reduces manual intervention, and improves the convenience and reliability of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a polishing head transferring a load tray to a polishing pad.

[0017] Figure 2 A schematic diagram of a wafer drop detection device for a polishing head provided in an embodiment of the present disclosure.

[0018] Figure 3 A schematic diagram of a projection direction provided by an embodiment of the present disclosure.

[0019] Figure 4 An exemplary diagram of another wafer drop detection device for a polishing head provided in an embodiment of the present disclosure.

[0020] Figure 5 This is an example diagram of another wafer drop detection device for a polishing head provided in an embodiment of the present disclosure.

[0021] Figure 6 This is an exemplary diagram of another wafer drop detection device for a polishing head provided in an embodiment of the present disclosure.

[0022] Figure 7 An exemplary diagram of another wafer drop detection device for a polishing head provided in an embodiment of the present disclosure.

[0023] Figure 8 A schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure.

[0024] The above drawings show clear embodiments of the present disclosure, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present disclosure in any way, but to illustrate the concepts of the present disclosure to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0027] CMP is a technique used for planarization or polishing of semiconductor components. It combines chemical and mechanical processes to smooth the semiconductor surface using a combination of physical grinding and chemical etching. The key components of CMP include polishing pad 3, abrasive slurry and polisher 1. Polishing pad 3 is a polymer pad against which the wafer rubs during the CMP process. Abrasive slurry typically contains colloidal nanoabrasives, soluble chemicals (polymers, surfactants, oxidants, inhibitors, passivators, chelating agents) and pH adjusters.

[0028] Reference Figure 1 As shown, the polishing machine may include a rotating shaft and a polishing head 12. Before starting polishing, the wafer (wafer) will be placed in a loading tray called Load Tray 2. This tray is used to temporarily store the wafer. The polishing head 12 is provided with a vacuum adsorption function for adsorbing and fixing the wafer from Load Tray 2.

[0029] Specifically, the polishing head 12 moves to the top of the Load Tray 2 and lifts the wafer from the tray by vacuum adsorption. Once the wafer is successfully adsorbed, the polishing head 12 will carry the wafer from the Load Tray 2 to the polishing position. During this movement, the polishing head 12 needs to accurately control its movement path and speed to ensure the smooth transfer of the wafer.

[0030] The polishing head 12 continues to move until the wafer contacts the polishing pad 3. At this point, the polishing head 12 will lower, allowing the wafer to lie flat on the polishing pad 3, and the polishing process will begin. During the polishing process, the polishing head 12 will polish the wafer at a specific pressure and speed to achieve the required surface flatness. After polishing is completed, the polishing head 12 will lift up and take the polished wafer off the polishing pad, and then move back to the Load Tray 2 area to release the wafer, completing the entire polishing process.

[0031] When the polishing head 12 is loading the wafer, if the wafer loading position is deviated or the adsorption pad is abnormal, the wafer may fall off during the process of moving the wafer from the Load Tray area to the contact with the polishing pad. When the wafer falls off during the loading process of the polishing head 12, and the equipment fails to detect this situation, the polishing head 12 may continue to polish without a wafer, which is the so-called "empty grinding". Empty grinding not only affects the life of the polishing pad 3, but may also cause equipment damage and increase maintenance costs. Since the wafer cannot be detected in time, the equipment may need to stop running after the problem is found, and clean and maintain it, which will cause production interruption and cause capacity loss. Long-term empty grinding and the inability to detect the wafer falling off in time will accelerate the wear of the polishing head 12 and the polishing pad, affect the stability and life of the equipment, and increase production costs.

[0032] Based on the above shortcomings, the present disclosure provides a chip drop detection device for the polishing head 12, referring to Figure 2 The detection device may include a light detection mechanism 4 and a controller 5, wherein the light detection mechanism 4 is used to collect surface light information of the polishing head 12 away from the rotating shaft when the polishing head 12 moves the wafer to contact the polishing pad, and the controller 5 is used to determine the adsorption state of the polishing head 12 to the wafer based on the surface light information.

[0033] The wafer drop detection device for the polishing head 12 provided in the embodiment of the present disclosure collects the surface light information of the polishing head 12 through the light detection mechanism 4, and the controller 5 determines the adsorption state of the polishing head 12 to the wafer according to the surface light information, and monitors the adsorption state of the polishing head 12 in real time. Once the wafer drop is found, the operation of the polishing head 12 can be stopped in time, thereby avoiding equipment damage and production capacity loss caused by wafer drop, and also reducing the time and resources lost due to equipment maintenance and cleaning, thereby improving the overall production capacity and efficiency. The device enhances the intelligence level of CMP equipment through automated light detection and control, reduces manual intervention, and improves the convenience and reliability of operation.

[0034] Reference Figure 2, the light detection mechanism 4 is arranged on the side of the polishing head 12 away from the rotating shaft. This layout allows the light detection mechanism 4 to effectively collect light information on the surface of the side of the polishing head 12 away from the rotating shaft when the polishing head 12 moves the wafer to contact the polishing pad, where the side away from the rotating shaft is the side for loading the wafer. And the projection of the light detection mechanism 4 in the direction of the central axis of the rotating shaft does not overlap with the polishing head 12, that is, in Figure 3 The projection of the polishing head 12 in the first direction does not coincide with the projection of the polishing head 12 in the first direction.

[0035] The light detection mechanism 4 collects surface light information of the side of the polishing head 12 away from the rotating shaft through a light sensor. The surface light information can be used to detect the adsorption state of the polishing head 12 to the wafer. Specifically, when the polishing head 12 adsorbs the wafer, the light detection mechanism 4 collects the surface light information reflected by the wafer. When the wafer falls, the surface light information reflected by the surface of the polishing head 12 is collected. Since different materials reflect different light information, the adsorption state of the polishing head 12 to the wafer can be judged based on the above surface light information. Optionally, the adsorption state can include adsorption and non-adsorption.

[0036] In some examples, the light detection mechanism 4 is communicatively connected with the controller 5 to transmit the surface light information collected by the light detection mechanism 4 to the controller 5. Optionally, the light sensor in the light detection mechanism 4 can convert the collected surface light information into electrical signals, which are directly transmitted to the controller 5 via wires. In some embodiments, the light detection mechanism 4 may use a digital signal output method to send the surface light information to the controller 5 in the form of a digital signal. This method can reduce signal interference and improve the accuracy and reliability of data transmission. In some cases, the communication between the light detection mechanism 4 and the controller 5 can be achieved wirelessly, such as using a Bluetooth or Wi-Fi module. This method can reduce the complexity of wiring. The method of transmitting the surface light information to the controller 5 can also be customized according to user needs, which will not be repeated in this example.

[0037] The controller 5 can be used to determine the adsorption state of the polishing head 12 on the wafer according to the surface light information. Specifically, the controller 5 can have a built-in data processing algorithm, which can perform real-time analysis on the surface light information collected by the light detection mechanism 4. The surface light information can include the intensity, wavelength distribution and other related optical properties of the light, which will not be described in detail here. The controller 5 can determine whether the polishing head 12 has correctly adsorbed the wafer by comparing the collected light information with the preset parameters.

[0038] If the collected light information matches the light characteristics of the wafer in the normal adsorption state, the controller 5 will determine the adsorption state as "adsorption"; conversely, if the light information matches the characteristics when the wafer is not adsorbed, the controller 5 will determine the adsorption state as "non-adsorption". This judgment logic can effectively detect whether the wafer has fallen off during the movement process.

[0039] For instance, taking wavelength as an example, the controller 5 may have built-in calibrated wavelength information corresponding to the light information reflected by the wafer, wherein the calibrated wavelength information may include wavelength ranges corresponding to different types of wafers. When the wavelength of the received surface light information is within the above wavelength range, the adsorption state of the polishing head 12 to the wafer is determined to be "adsorbed"; when the wavelength of the received surface light information is outside the above wavelength range, the adsorption state of the polishing head 12 to the wafer is determined to be "not adsorbed".

[0040] The controller 5 determines the adsorption state of the polishing head 12 to take corresponding response measures. Figure 4 The polishing head 12 may be provided with a vacuum adsorption device 6. If the controller 5 determines that the adsorption state is "adsorption", the controller 5 will maintain the current working state of the polishing head 12 and continue the wafer handling or polishing operation. If it is determined to be "non-adsorption", the controller 5 will immediately take measures, such as stopping the movement of the polishing head 12, releasing the vacuum adsorption device 6 in the polishing head 12, that is, controlling the vacuum adsorption device 6 to stop working, and sending an alarm signal to the operator to prevent the polishing head 12 from continuing to operate without a wafer, thereby avoiding equipment damage and production accidents.

[0041] Optionally, the vacuum adsorption device 6 is disposed inside the polishing head 12 to complete the adsorption of the wafer by means of negative pressure.

[0042] Optionally, the alarm signal may be issued by an alarm mechanism 51 , which is connected to the controller 5 and is used to issue an alarm signal. The alarm signal may be in the form of sound, light, etc., which will not be elaborated in this example implementation.

[0043] In some examples, the controller 5 is connected in communication with the vacuum adsorption device 6 . The communication connection method can refer to the communication connection between the light detection mechanism 4 and the controller 5 , which will not be described in detail here.

[0044] In some examples, reference Figure 4 The controller 5 is independent of the polishing head 12 and is supported by other supporting structures on the side of the optical head close to the rotating shaft. For example, the controller 5 is fixed on a mechanical arm connected to the polishing head 12 (not shown). It can also be a supporting structure outside the polishing machine, which is not specifically limited here. Figure 5The controller 5 may also be installed on the rotating shaft, which will not be described in detail in this example implementation.

[0045] In some examples, the light detection mechanism 4 is fixed to the controller 5 through a connection structure, and when the controller 5 is supported by other supporting structures, the light detection mechanism 4 will not rotate with the rotation of the polishing head 12. When the controller 5 is fixed to the shaft, when the shaft rotates, the light sensor will be driven to rotate through the controller 5.

[0046] In some examples, the light detection mechanism 4 may also be directly connected to the rotating shaft, or to a mechanical arm (not shown) for supporting the controller 5, which is not described in detail in this example implementation.

[0047] In some examples, reference Figure 6 The detection device may also be provided with a telescopic mechanism 7 for controlling the position of the light detection mechanism 4, specifically, for controlling the position of the light detection mechanism 4 in the direction of the central axis of the rotating shaft. The telescopic mechanism 7 may be the above-mentioned connection structure for fixing the light detection mechanism 4 on the controller 5.

[0048] Specifically, the telescopic mechanism 7 can be used to move the light detection mechanism 4 away from the polishing head 12 when the distance between the polishing head 12 and the polishing pad is less than a preset distance; wherein the preset distance is the minimum distance at which the light collection mechanism can collect surface light information, so as to prevent the light detection mechanism 4 from causing damage to the polishing pad.

[0049] In some examples, reference Figure 6 The light detection mechanism 4 can be rotatably installed on the telescopic mechanism 7. When the controller 5 detects that the light information collected by the light detection mechanism 4 is not accurate enough, it can control the telescopic mechanism 7 to drive the light detection mechanism 4 to move, and control the light detection mechanism 4 to rotate, so as to collect more accurate light information and improve the detection accuracy of the polishing head 12 falling off.

[0050] Optional, see Figure 7 A distance sensor 8 can be set on the retaining piece on the side of the polishing head 12 to collect the distance between the polishing head 12 and the polishing pad. At the same time, the distance sensor 8 can also detect whether there is a wafer flying out of the polishing head 12 during the polishing process. Specifically, during the polishing process, the distance between the polishing head 12 and the polishing pad can be detected in real time. When the distance suddenly changes, it is caused by the flying of wafer fragments, so it can be determined whether flying wafers occur during the polishing process.

[0051] The movement of the telescopic mechanism 7 can be controlled by the controller 5, which can receive the distance information transmitted by the distance sensor 8, and when the distance in the distance information is less than the preset distance, control the telescopic mechanism 7 to move the light detection mechanism 4 away from the polishing pad.

[0052] It should be noted that the light collected by the light detection mechanism 4 is natural light reflected by the surface of the wafer or the polishing head away from the rotating shaft. In some examples, a light source can also be set to irradiate the side of the polishing head 12 away from the rotating shaft to reduce the difficulty of light collection by the light detection mechanism 4. The setting position of the light source can be customized according to user needs and will not be elaborated in this example implementation.

[0053] The wafer drop detection device of the polishing head 12 provided by the embodiment of the present disclosure collects the surface light information of the polishing head 12 through the light detection mechanism 4, and the controller 5 can monitor the adsorption state of the polishing head 12 to the wafer in real time. Once the wafer is detected to fall off, the controller 5 can quickly stop the operation of the polishing head 12, avoiding equipment damage and production capacity loss caused by the wafer falling off, reducing the time and resources lost due to equipment maintenance and cleaning, and improving the overall production capacity and efficiency. Through automated light detection and control, the intelligence level of the CMP equipment is enhanced, manual intervention is reduced, and the convenience and reliability of operation are improved. By setting the telescopic mechanism 7, the position of the light detection mechanism 4 can be dynamically adjusted according to the distance between the polishing head 12 and the polishing pad, ensuring that the light sensor is always within the effective working range, and improving the detection accuracy. The design of the light detection mechanism 4 enables it to adapt to different changes in the distance between the polishing head 12 and the polishing pad, improving the adaptability and flexibility of the detection device. When the wafer falls off, the controller 5 will stop the movement of the polishing head 12 and release the vacuum adsorption device 6 to avoid empty grinding and flying wafers, thereby preventing the polishing head 12 from continuing to operate without a wafer, avoiding equipment damage and production accidents. The design of the telescopic mechanism 7 can move the light sensor to a safe position when the distance between the polishing head 12 and the polishing pad is too close, so as to avoid collision between the light sensor and the polishing pad and protect the light sensor and the polishing pad from damage.

[0054] The present disclosure also provides a method for detecting chip drop of the polishing head 12, referring to Figure 8 As shown, applied to the above-mentioned controller 5, the chip drop detection method may include steps S810 to S820.

[0055] In step S810, when the polishing head 12 moves the wafer to contact the polishing pad, surface light information on the side of the polishing head 12 away from the rotating shaft is obtained; The controller 5 is used to obtain the surface light information of the polishing head 12 away from the rotating shaft when the polishing head 12 moves the wafer to contact the polishing pad. The surface light information is sent by the light detection mechanism 4. The specific sending process has been described in detail above, so it will not be repeated here.

[0056] In step S820, the adsorption state of the polishing head 12 to the wafer is determined according to the surface light information.

[0057] The controller 5 can determine the adsorption state of the polishing head 12 on the wafer according to the surface light information. Specifically, the controller 5 can have a built-in data processing algorithm, which can perform real-time analysis on the surface light information collected by the light detection mechanism 4. The surface light information may include the intensity, wavelength distribution and other related optical properties of the light, which will not be described in detail here. The controller 5 can determine whether the polishing head 12 has correctly adsorbed the wafer by comparing the collected light information with the preset parameters.

[0058] If the collected light information matches the light characteristics of the wafer in the normal adsorption state, the controller 5 will determine the adsorption state as "adsorption"; conversely, if the light information matches the characteristics when the wafer is not adsorbed, the controller 5 will determine the adsorption state as "non-adsorption". This judgment logic can effectively detect whether the wafer has fallen off during the movement process.

[0059] For instance, taking wavelength as an example, the controller 5 may have built-in calibrated wavelength information corresponding to the light information reflected by the wafer, wherein the calibrated wavelength information may include wavelength ranges corresponding to different types of wafers. When the wavelength of the received surface light information is within the above wavelength range, the adsorption state of the polishing head 12 to the wafer is determined to be "adsorbed"; when the wavelength of the received surface light information is outside the above wavelength range, the adsorption state of the polishing head 12 to the wafer is determined to be "not adsorbed".

[0060] The controller 5 determines the adsorption state of the polishing head 12, and it will take corresponding response measures. Figure 4 If it is judged as "adsorption", the controller 5 will maintain the current working state of the polishing head 12 and continue the wafer handling or polishing operation. If it is judged as "non-adsorption", the controller 5 will immediately take measures, such as stopping the movement of the polishing head 12, releasing the vacuum adsorption device 6 in the polishing head 12, that is, controlling the vacuum adsorption device 6 to stop working, and sending an alarm signal to the operator to prevent the polishing head 12 from continuing to operate without a wafer, thereby avoiding equipment damage and production accidents.

[0061] In the above embodiments, the description of each embodiment has its own emphasis. For the part not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the inventions claimed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not claimed in the present disclosure.

[0063] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A chip drop detection device for a polishing head, characterized in that: include: A light detection mechanism, used to collect surface light information on the side of the polishing head away from the rotating shaft when the polishing head moves the wafer to contact the polishing pad; The controller is used to determine the adsorption state of the polishing head to the wafer according to the surface light information.

2. The detection device according to claim 1, characterized in that: The light detection mechanism comprises a light sensor, which is located at a side of the polishing head away from the rotating shaft, and whose orthographic projection along the central axis direction of the rotating shaft does not overlap with the polishing head.

3. The detection device according to claim 1, characterized in that: The polishing head includes a vacuum adsorption device; The controller is connected to the vacuum adsorption device of the polishing head and is used to control the working state of the vacuum adsorption device according to the adsorption state.

4. The detection device according to claim 3, characterized in that: The adsorption state includes adsorption and non-adsorption; The controller is used for controlling the vacuum adsorption device to stop working when the adsorption state is non-adsorption.

5. The detection device according to claim 4, characterized in that: The detection device also includes: The alarm mechanism is used to send out an alarm signal when the adsorption state is not adsorbed.

6. The detection device according to claim 1, characterized in that: The controller is used to determine the adsorption state according to the collected wavelength information in the light information.

7. The detection device according to claim 1, characterized in that: The detection device also includes: a telescopic mechanism connected between the controller and the light detection mechanism, and used for moving the light detection mechanism away from the polishing pad when the distance between the polishing head and the polishing pad is less than a preset distance; The preset distance is the minimum distance at which the light collection mechanism can collect the surface light information.

8. A method for detecting chip drop of a polishing head, characterized in that: Applicable to controllers, including: When the polishing head moves the wafer to contact the polishing pad, obtaining surface light information of the side of the polishing head away from the rotating shaft; The adsorption state of the polishing head to the wafer is determined according to the surface light information.

9. The method according to claim 8, characterized in that The adsorption state includes adsorption and non-adsorption; Determining the adsorption state of the polishing head to the wafer according to the surface light information also includes: Obtaining the collected wavelength information in the light information and the calibrated wavelength information reflected by the wafer; When the acquisition wavelength information is different from the calibration wavelength information, it is determined that the adsorption state is not adsorbed.

10. The method according to claim 9, characterized in that The polishing head includes a vacuum adsorption device and an alarm mechanism; the method also includes: When the adsorption state is non-adsorption, the vacuum adsorption device is controlled to stop working, and the alarm mechanism is controlled to send out an alarm signal.

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