Wafer monitoring method for non-metal cmp, cmp apparatus, computer storage medium

Abstract

This application provides a wafer monitoring method, CMP equipment, and computer storage medium for non-metallic CMP. The method includes: during the chemical mechanical polishing of the metal layer of a wafer by the CMP equipment, acquiring at least one first image captured by an image acquisition device, and a wafer signal acquired by an eddy current sensor when the eddy current sensor is relative to the wafer in a direction perpendicular to the polishing pad. The CMP equipment includes a polishing head, a polishing pad, and a liquid supply arm. The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used to supply polishing liquid to the polishing surface, and the image acquisition device is used to acquire an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad. Based on the width of the bow wave in the at least one first image and the wafer signal, it is determined whether the wafer has slipped relative to the polishing head. This solution can make the monitoring results of wafer slippage more accurate.

Description

[0001] This application is a divisional application of the invention patent application filed on December 23, 2024, with application number 2024118982573. Technical Field

[0002] This application relates to the field of wafer polishing technology, and more particularly to a wafer monitoring method, CMP equipment, and computer storage medium for non-metallic CMP. Background Technology

[0003] During wafer manufacturing, chemical mechanical polishing (CMP) is used to planarize the metal layers on the wafer surface.

[0004] CMP equipment includes a polishing head and a polishing pad. The polishing head is equipped with an optical sensor. During the CMP process, the polishing head moves the wafer to press against the polishing pad and rotates and translates the wafer relative to the polishing pad, whose surface is supplied with polishing fluid, to polish the wafer. The optical sensor is used to monitor whether the wafer has slipped (slipping refers to the wafer detaching from the polishing head). For example, when slipping occurs, the wafer slides off the polishing head and passes through the monitoring optical path of the optical sensor, so that the light collected by the optical sensor changes from the laser reflected from the polishing pad to the laser reflected from the wafer. At this time, it can be determined that the wafer has slipped.

[0005] However, when wafer slippage occurs, the light collected by the optical sensor after passing through the monitoring optical path will revert to the laser reflected by the polishing pad. Therefore, the time when the wafer slippage occurs is relatively short, and false alarms and missed alarms are prone to occur when monitoring wafer slippage. As a result, the monitoring results of wafer slippage monitoring are relatively inaccurate. Summary of the Invention

[0006] In view of this, embodiments of this application provide a wafer monitoring method, CMP equipment, and computer storage medium for non-metallic CMP, to at least partially solve the above-mentioned problems.

[0007] According to a first aspect of the present application, a wafer monitoring method for metal CMP is provided, comprising: during the chemical mechanical polishing of the metal layer of a wafer by a CMP device, acquiring at least one first image acquired by an image acquisition device, and a wafer signal acquired by an eddy current sensor when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad, wherein the CMP device includes a polishing head, a polishing pad, and a liquid supply arm, the polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used to supply polishing liquid to the polishing surface, and the image acquisition device is used to acquire an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad; and determining whether the wafer has slipped relative to the polishing head based on the width of the bow wave in the at least one first image and the wafer signal.

[0008] According to a second aspect of the present application, a wafer monitoring method for non-metallic CMP is provided, comprising: during the chemical mechanical polishing of a non-metallic layer of a wafer by a CMP device, acquiring at least one first image acquired by an image acquisition device and at least one torque value of a driving member, wherein the CMP device includes a polishing head, a polishing pad, and a liquid supply arm, the polishing head being used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm being used to supply polishing liquid to the polishing surface, the image acquisition device being used to acquire an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad, and the driving member being used to control the rotation of the polishing pad or the polishing head; determining whether the wafer has slipped relative to the polishing head based on the width of the bow wave in the at least one first image and the at least one torque value.

[0009] According to a third aspect of the embodiments of this application, a wafer monitoring method for chemical mechanical polishing (CMP) is provided, comprising: acquiring at least one first image acquired by an image acquisition device during the CMP process of a wafer, wherein the CMP device includes a polishing head, a polishing pad, and a liquid supply arm, the polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used to supply polishing liquid to the polishing surface, and the image acquisition device is used to acquire an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad; if the width of the bow wave in the at least one first image meets a second slip condition, it is determined that the wafer has slipped relative to the polishing head.

[0010] According to a fourth aspect of the embodiments of this application, a CMP apparatus is provided, comprising: a polishing pad, a polishing head, a liquid supply arm, an image acquisition unit, an eddy current sensor, and a controller; a polishing pad is disposed on one side of the polishing pad; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad and to drive the wafer to move relative to the polishing pad, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing fluid to the polishing pad during the chemical mechanical polishing of the wafer; the image acquisition unit is used to acquire an image of the bow wave formed by the polishing fluid near the polishing head on the polishing pad; the eddy current sensor is used to acquire wafer signals when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad; and the controller is used to execute the method of the first aspect described above.

[0011] According to a fifth aspect of the embodiments of this application, a CMP apparatus is provided, comprising: a polishing pad, a polishing head, a liquid supply arm, an image acquisition unit, a drive unit, and a controller; a polishing pad is disposed on one side of the polishing pad; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad and to drive the wafer to move relative to the polishing pad, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing fluid to the polishing pad during the chemical mechanical polishing of the wafer; the image acquisition unit is used to acquire an image of the bow wave formed by the polishing fluid near the polishing head on the polishing pad; the drive unit is used to control the rotation of the polishing pad or the polishing head; and the controller is used to execute the method of the second aspect described above.

[0012] According to a sixth aspect of the embodiments of this application, a CMP apparatus is provided, comprising: a polishing pad, a polishing head, a liquid supply arm, an image acquisition device, and a controller; a polishing pad is disposed on one side of the polishing pad; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad and to drive the wafer to move relative to the polishing pad, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing fluid to the polishing pad during the chemical mechanical polishing of the wafer; the image acquisition device is used to acquire an image of the bow wave formed by the polishing fluid near the polishing head on the polishing pad; and the controller is used to execute the method of the third aspect described above.

[0013] According to a seventh aspect of the embodiments of this application, a computer storage medium is provided, on which a computer program is stored, the program being executed by a processor using the methods of the first aspect, the second aspect, or the third aspect described above.

[0014] According to an eighth aspect of the embodiments of this application, a computer program product is provided, including computer instructions that instruct a computing device to perform the methods of the first aspect, the second aspect, or the third aspect described above.

[0015] According to the wafer monitoring scheme for metal CMP provided in this application embodiment, during the chemical mechanical polishing of the metal layer of a wafer by a CMP device, at least one first image is acquired by an image acquisition device, and a wafer signal is acquired by an eddy current sensor when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad. Based on the width of the bow wave in the at least one first image and the wafer signal, it is determined whether the wafer has slipped relative to the polishing head. Therefore, compared to detecting wafer slippage by detecting the relatively short-lived changes in laser light acquired by an optical sensor, this application embodiment monitors wafer slippage by the width of the bow wave near the polishing head on the polishing pad and the wafer signal. When wafer slippage occurs, the width of the aforementioned bow wave remains almost consistently small, and the signal strength of the wafer signal, after rapidly decreasing to 0, also remains essentially stable at 0. This reduces the possibility of false alarms and missed alarms when monitoring wafer slippage, making the monitoring results more accurate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of a CMP device according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of wafer signals according to an embodiment of this application;

[0019] Figure 3 This is a flowchart of a wafer monitoring method for metal CMP according to an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the signal strength variation curve according to an embodiment of this application;

[0021] Figure 5 This is a flowchart illustrating the determination of whether the second sliding plate condition is met, according to one embodiment of this application.

[0022] Figure 6 This is a schematic diagram of the first and second sub-curve graphs according to an embodiment of this application;

[0023] Figure 7 This is a flowchart illustrating the determination of whether the second sliding plate condition is met, according to another embodiment of this application.

[0024] Figure 8 This is a flowchart illustrating the determination of whether the second sliding plate condition is met, according to yet another embodiment of this application.

[0025] Figure 9 This is a flowchart illustrating the determination of whether the second sliding plate condition is met in another embodiment of this application;

[0026] Figure 10 This is a flowchart of a wafer monitoring method for non-metallic CMP according to an embodiment of this application;

[0027] Figure 11 This is a flowchart of a wafer monitoring method for chemical mechanical polishing according to an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Polishing disc; 11. Polishing pad; 2. Polishing head holder; 3. Polishing head; 4. Image acquisition device. Detailed Implementation

[0030] This application provides a wafer monitoring method for metal CMP, which can be applied to CMP equipment, etc., and this application does not limit it.

[0031] Figure 1 This is a schematic diagram of a CMP device according to an embodiment of this application. Figure 1As shown, w represents a wafer. The CMP equipment is used to perform chemical mechanical polishing on the wafer, specifically on the metal layers of the wafer. The CMP equipment includes: a polishing disc 1, a polishing head holder 2, a polishing head 3, a liquid supply arm, an image acquisition device 4 (e.g., a high-speed camera), an eddy current sensor, and a controller. A circular polishing pad 11 is provided on one side of the polishing disc 1. The polishing disc 1 drives the polishing pad 11 to rotate around its axis. The side of the polishing pad 11 away from the polishing disc 1 is the polishing surface. The polishing head holder 2 is connected to the polishing head 3, which is located between the polishing head holder 2 and the polishing pad 11. The polishing head holder 2 drives the polishing head 3 to bring the wafer abutting against the polishing surface, specifically bringing the metal layers on the wafer to be polished against the polishing surface. It also drives the polishing head 3 to make the wafer rotate relative to the polishing pad 11 around its axis and to make the wafer reciprocate radially along the polishing surface to perform chemical mechanical polishing on the wafer. The system includes: a light source; a liquid supply arm for supplying polishing fluid to the polishing pad 11 during chemical mechanical polishing (CMP); an image acquisition unit 4 connected to the polishing head support 2, with its lens facing the polishing pad 11 near the polishing head 3, for acquiring images of the bow wave formed by the polishing fluid near the polishing head 3 on the polishing pad 11; an eddy current sensor housed within the polishing disk 1, for example, a mounting slot for the eddy current sensor can be provided on the side of the polishing disk 1 near the polishing pad 11; during CMP, the eddy current sensor rotates with the polishing disk 1 so that for part of the CMP process, the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad, and at other times, the eddy current sensor is not opposite to the wafer in a direction perpendicular to the polishing pad; and a controller for executing a wafer monitoring method for metal CMP.

[0032] Optionally, both the polishing head 3 and the polishing head support 2 can be cylindrical in shape. The image acquisition device 4 can be detachably or fixedly connected to the bottom edge of the polishing head support 2. During the chemical mechanical polishing process, since the axes of the polishing head support 2, the polishing head 3, and the wafer are all coincident, and the reciprocating movement of the wafer is achieved by external force driving the polishing head support 2 to reciprocate, the polishing head 3 will rotate around the wafer's own axis relative to the image acquisition device 4. However, the relative position between the polishing head 3 and the image acquisition device 4 will not change, so that the image acquisition device 4 can more stably acquire the bow wave image on the polishing pad 11 near the polishing head 3. Specifically, it can more stably acquire the bow wave image on the polishing pad 11 near the bottom edge of the polishing head 3.

[0033] It should be noted that, as Figure 2As shown, when the eddy current sensor is facing a metal object, it will generate an induced magnetic field (effective magnetic field) on the metal object, so that the eddy current sensor can collect signals. Thus, when the eddy current sensor is facing the wafer in a direction perpendicular to the polishing pad, it can collect wafer signals.

[0034] The wafer monitoring method for metal CMP is described in detail below through several embodiments.

[0035] Figure 3 This is a flowchart of a wafer monitoring method for metal CMP according to one embodiment of this application. Figure 3 As shown, the wafer monitoring method for metal CMP includes the following steps:

[0036] Step 301: During the chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, acquire at least one first image acquired by the image acquisition device, and the wafer signal acquired by the eddy current sensor when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad.

[0037] In one specific embodiment, during the chemical mechanical polishing (CMP) process of a wafer, an image acquisition unit can be controlled to periodically acquire images of the bow wave near the bottom edge of the polishing head on the polishing pad, and all acquired images can be used as the first image. Furthermore, the wafer signal acquired by the eddy current sensor when it is positioned perpendicular to the polishing pad and relative to the wafer can also be obtained. In this embodiment, the image acquisition period of the image acquisition unit is not limited; for example, the image acquisition unit can be controlled to acquire the first image at a shutter speed of 0.02s and an image acquisition frequency of 5Hz.

[0038] Step 302: Determine whether the wafer has slipped relative to the polishing head based on the width of the bow wave in at least one first image and the wafer signal.

[0039] During chemical mechanical polishing (CMP), whether the wafer slips directly affects the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer is not slipping, the polishing head holds the wafer against the polishing pad, and a liquid film of polishing fluid exists between the wafer and the polishing pad. In this case, the width of the bow wave in the first image is stable around a first value. When the wafer slips, the space below the polishing head changes abruptly, and the polishing fluid switches from one steady state to another, causing the width of the bow wave in the first image to change, for example, stabilizing around a second value, because the wafer slips out from under the polishing head. Afterwards, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the wafer pressure between the polishing head and the polishing pad decreases, so the flow rate of the polishing fluid between the polishing head and the polishing pad increases, and the amount of polishing fluid accumulated on the polishing pad near the bottom edge of the polishing head decreases. Therefore, compared with the first image acquired when the wafer is not slid, the width of the bow wave in the first image acquired when the wafer is slid is generally smaller, that is, the second value is generally smaller than the first value. For example, the first value is 8mm and the second value is 5mm, or the first value is 12mm and the second value is 8mm, etc.

[0040] It should be noted that during chemical mechanical polishing, due to the inherent volatility of the flowing polishing fluid and the reciprocating movement of the polishing head along the radial direction of the polishing pad, the bow wave width will exhibit relatively regular and large fluctuations regardless of whether the wafer is being slid. In addition, the bow wave width will stabilize around different values ​​when the wafer is not being slid and when it is being slid. Therefore, the first and second values ​​mentioned above are approximate values ​​of the bow wave width in the first image acquired when the bow wave is relatively stable.

[0041] During chemical mechanical polishing (CMP), whether the wafer slips directly affects the wafer signal. Specifically, when the wafer is not slipped, as CMP progresses, the polished metal layer gradually thins until the required thickness is achieved, causing the wafer signal strength to gradually decrease to a value greater than 0. When the wafer slips, it detaches from the polishing head, resulting in the eddy current sensor being almost not in contact with the wafer or only in contact for a very short time in the direction perpendicular to the polishing pad. Consequently, the eddy current sensor cannot detect the metal layer or detects it for a very short time, causing the wafer signal strength to rapidly decrease to 0. Therefore, compared to the wafer signal when it is not slipped, the wafer signal strength decreases to a smaller value much faster when it is slipped.

[0042] Based on this, in one specific embodiment, after acquiring at least one first image and the wafer, the width of the bow wave in each first image can be determined. When the width of the bow wave in the acquired at least one first image is small and the signal strength of the wafer signal decreases to a small value quickly, it can be determined whether the wafer has slipped relative to the polishing head. Otherwise, it is determined that the wafer has not slipped relative to the polishing head, thus realizing the monitoring of wafer slip.

[0043] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or it can be calculated by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head in the image acquisition area of ​​the image acquisition device. In this embodiment, the specific method for determining the width of the bow wave in the image is not limited.

[0044] In this embodiment, during the chemical mechanical polishing (CMP) process of the metal layer of a wafer, at least one first image is acquired by an image acquisition device, and a wafer signal is acquired by an eddy current sensor when the eddy current sensor is relative to the wafer in a direction perpendicular to the polishing pad. Based on the width of the bow wave in the at least one first image and the wafer signal, it is determined whether the wafer has slipped relative to the polishing head. Therefore, compared to detecting wafer slippage through the relatively short-lived changes in laser light acquired by an optical sensor, this embodiment detects wafer slippage by measuring the width of the bow wave near the polishing head on the polishing pad and the wafer signal. When wafer slippage occurs, the width of the aforementioned bow wave remains almost consistently small, and the signal strength of the wafer signal, after rapidly decreasing to 0, also remains essentially stable at 0. This reduces the possibility of false alarms and missed alarms when monitoring wafer slippage, making the monitoring results more accurate.

[0045] Furthermore, when determining whether the wafer has slipped relative to the polishing head, a dual judgment is made based on the width of the bow wave on the polishing pad near the polishing head and the wafer signal, which can make the monitoring results of wafer slipping more accurate.

[0046] The above step 302 can be implemented in at least the following two ways.

[0047] In one possible implementation, step 302 includes the following specific processing: if the wafer signal meets the first sliding condition and the width of the bow wave in at least one first image meets the second sliding condition, then it is determined that the wafer has slipped relative to the polishing head.

[0048] In this embodiment, compared to the next implementation where the width of the bow wave in at least one first image is determined to meet the second sliding condition after the wafer signal meets the first sliding condition, this embodiment does not limit the order of determining whether the first sliding condition and the second sliding condition are met. The two can be performed simultaneously, which improves the efficiency of determining whether the wafer has slipped relative to the polishing head.

[0049] In another possible implementation, step 302 includes the following specific processing: if the wafer signal meets the first sliding condition, then determine whether the width of the bow wave in the at least one first image meets the second sliding condition; if the width of the bow wave in the at least one first image meets the second sliding condition, then determine that the wafer has slid relative to the polishing head. Specifically, it can be first determined whether the wafer signal meets the first sliding condition; if the wafer signal meets the first sliding condition, then determine whether the width of the bow wave in the at least one first image meets the second sliding condition; if yes, then determine that the wafer has slid relative to the polishing head; otherwise, determine that the wafer has not slid relative to the polishing head; if the wafer signal does not meet the first sliding condition, then determine that the wafer has not slid relative to the polishing head.

[0050] In this embodiment, compared to the previous implementation which did not specify the order of determining whether the first sliding condition and the second sliding condition are met, this embodiment determines whether the width of the bow wave in the at least one first image meets the second sliding condition after the wafer signal meets the first sliding condition. Thus, if the wafer signal does not meet the first sliding condition, it is not necessary to determine whether the width of the bow wave in the at least one first image meets the second sliding condition, saving computational resources.

[0051] In one possible implementation, the wafer monitoring method for metal CMP further includes the following processing: if the signal strength of the wafer signal is less than the strength threshold, or the absolute value of the slope of the wafer signal is greater than the slope threshold, then the wafer signal is determined to meet the first sliding condition; otherwise, the wafer signal is determined not to meet the first sliding condition.

[0052] The intensity threshold and slope threshold can be set according to actual needs. This application embodiment does not limit this. The intensity threshold is greater than or equal to 0 and less than the target signal intensity. The target signal intensity is the signal intensity of the wafer signal when the pre-calibrated metal layer reaches the target thickness. The target thickness is the thickness of the metal layer when the pre-set chemical mechanical polishing is completed normally.

[0053] In a specific example, such as Figure 4 As shown, Figure 4 The standard curve in the figure represents the signal intensity change curve of the wafer signal when no slippage occurs. Figure 4 The abnormal curve in the figure represents the signal intensity change curve of the wafer signal before and after slippage. It can be seen that the wafer slippage occurs around the inflection point of the abnormal curve. At any position after the inflection point of the abnormal curve, the signal intensity of the wafer signal is less than the intensity threshold, or the absolute value of the slope of the wafer signal is greater than the slope threshold. Therefore, it can be determined that the wafer signal corresponding to the abnormal curve meets the first slippage condition. However, at any position in the normal curve, the signal intensity of the wafer signal is not less than the intensity threshold, nor is the absolute value of the slope of the wafer signal greater than the slope threshold. Therefore, it can be determined that the wafer signal corresponding to the normal curve does not meet the first slippage condition.

[0054] In one possible implementation, an image acquisition device is used to acquire an image of the bow wave on the polishing pad near the target portion of the polishing head, the target portion being the part of the polishing head near the supply arm.

[0055] In one specific embodiment, the image acquisition unit can be located between the liquid supply arm and the polishing head in a direction parallel to the polishing pad. The lens of the image acquisition unit is directed towards the target portion of the polishing pad near the polishing head. As a result, the image acquisition unit can acquire the bow wave as close as possible to the liquid supply arm, thereby acquiring a wider bow wave and a more obvious bow wave, which can make the monitoring results of wafer slip monitoring more accurate.

[0056] Optionally, the image acquisition unit may also be connected to an air jet assembly for cleaning the image acquisition unit, in order to reduce the impact of polishing fluid splashed onto the image acquisition unit on the clarity of the images acquired by the image acquisition unit.

[0057] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing solution for image acquisition. If a fluorescent dye is added to the polishing solution, the chemical mechanical polishing process should be carried out in a closed, light-protected environment, and an ultraviolet lamp should be added to the environment to make the bow waves in the image acquired by the image acquisition device clearer.

[0058] The method for determining whether the width of the bow wave in at least one of the first images meets the second sliding condition can be as follows: Based on at least one of the first bow wave width, first change data, second change data, and the comparison result of the first change data, determine whether the width of the bow wave in at least one of the first images meets the second sliding condition. The first bow wave width is the width obtained based on the width of the bow wave in the at least one first image. The first change data indicates how the width of the bow wave in the first image changes with the time the first image is acquired during the monitoring period. The second change data indicates how the width of the bow wave in the second image acquired by the image acquisition device changes with the time the second image is acquired during a control period in which the wafer does not slip relative to the polishing head.

[0059] Based on this, there are at least three specific ways to determine whether the width of the bow wave in at least one of the first images meets the second slider condition. Figure 5 This is a flowchart illustrating the determination of whether the second sliding condition is met, according to one embodiment of this application. Figure 5 As shown, determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data may include the following steps:

[0060] Step 501: Determine the width of the first bow wave based on the width of the bow wave in at least one of the first images.

[0061] Step 502: If the width of the first bow wave is less than the first width threshold, then it is determined that the width of the bow wave in at least one of the first images meets the second slider condition.

[0062] In one specific implementation, during the chemical mechanical polishing (CMP) process of the wafer's metal layer, a first curve can be plotted based on the width of the bow wave in the acquired first image. This first curve is updated synchronously as more first images are acquired. The vertical axis of the first curve represents the bow wave width, and the horizontal axis represents the duration of the first image acquisition. Based on this, a first sub-curve corresponding to the monitoring time period is determined in the first curve, and a portion with a relatively stable width is identified within the first sub-curve. The first bow wave width is then determined based on this portion. After determining the first bow wave width, if the first bow wave width is less than a first width threshold, it is determined that the bow wave width in at least one of the first images meets the second sliding condition; otherwise, it is determined that the bow wave width in at least one of the first images does not meet the second sliding condition. The first width threshold can be set according to the actual polishing conditions, typically around 5mm-10mm, for example, it can be set to 5mm or 8mm.

[0063] For example, in Figure 6 In the middle, the dashed curve (i.e. Figure 6a) in the figure is the first sub-curve corresponding to the monitoring time period (0s to 20s). The image acquired by the image acquisition device during the monitoring time period is the above-mentioned at least one first image. By observing the first sub-curve, it can be seen that 0s to 1s, 2s to 6s, 8s to 12s, 13s to 17s and 19 to 20s in the detection time period are all parts with relatively stable widths represented by the first sub-curve. It can be clearly seen from the figure that the width represented by this part is about 5mm. Therefore, it can be determined that the width of the first bow wave is 5mm. Based on the fact that the width of the first bow wave is less than the first width threshold (the first width threshold is set to 8mm), it is determined that the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition.

[0064] In this embodiment of the application, when the width of the first bow wave determined based on the width of the bow wave in the at least one first image is sufficiently small, it can be determined that the width of the bow wave in the at least one first image meets the second slider condition, which can simplify the judgment logic and save computational resources.

[0065] Optionally, the wafer monitoring method for metal CMP further includes the following processing: during the chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, acquiring at least one third image captured by an image acquisition device when the wafer does not slip relative to the polishing head; determining a second bow wave width based on the bow wave width in the at least one third image; and determining a first width threshold based on the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

[0066] In one specific implementation, during the chemical mechanical polishing (CMP) process of the wafer's metal layer, when the wafer does not slip relative to the polishing head, a second curve can be plotted based on the width of the bow wave in the acquired third image. This second curve is updated synchronously as more third images are acquired. Based on this, the vertical axis of the second curve represents the width of the bow wave, and the horizontal axis represents the duration of acquiring the third image. A second sub-curve corresponding to the reference time period is determined in the second curve, and a portion of the width that is relatively stable is identified in the second sub-curve. The second bow wave width is then determined based on this portion. After determining the second bow wave width, a value less than or equal to the second bow wave width can be used as a first width threshold.

[0067] For example, in Figure 6 In the middle, the solid line curve (i.e. Figure 6b) in the figure represents the second sub-curve. The image acquired by the image acquisition device during the control time period is at least one of the third images mentioned above. By observing the second sub-curve, it can be seen that 0s to 1s, 3s to 6s, 8s to 12s, 14s to 17s, and 19 to 20s in the detection time period are all relatively stable parts represented by the second sub-curve. It can be clearly seen from the figure that the width represented by this part is about 8mm. Therefore, it can be determined that the width of the second bow wave is 8mm. Based on the fact that the first width threshold is less than or equal to the width of the second bow wave, it can be determined that the first width threshold is 8mm.

[0068] In this embodiment, the first width threshold is less than or equal to the second bow wave width, which can make the first bow wave width, which is less than the first width threshold, also less than the second bow wave width. Since the width of the bow wave is generally stable at less than the second bow wave width when the wafer is sliding, determining that at least one of the above-mentioned first images meets the second sliding condition when the first bow wave width is less than the second bow wave width can make the result of determining whether the second sliding condition is met more accurate.

[0069] Optionally, the first width threshold is positively correlated with the second bow wave width. For example, when the second bow wave width is 8mm, the first width threshold can be 5mm; when the second bow wave width is 12mm, the first width threshold can be 8mm.

[0070] Figure 7 This is a flowchart illustrating the determination of whether the second sliding condition is met, according to another embodiment of this application. Figure 7 As shown, based on the fact that the at least one first image is a plurality of first images acquired by the image acquisition device during the monitoring period, determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data can include the following steps:

[0071] Step 701: Determine the first change data based on multiple first images.

[0072] Step 702: Based on the first change data, determine whether the width of the bow wave in the multiple first images meets the second slider condition.

[0073] The first change data can be a curve, a mapping function, or a mapping table, etc., and this application embodiment does not limit it.

[0074] In one specific implementation, the first change data can be a curve showing the change in the width of the bow wave in the first image over the monitoring period as a function of the time it takes for the first image to be acquired. For example... Figure 6The dashed curve in the image can be used to determine the overall change in the width of the bow wave in the first image acquired by the image acquisition device during the monitoring period based on the first change data. Based on this, it can be determined whether the width of the bow wave in multiple first images meets the second slider condition.

[0075] In this embodiment of the application, when determining whether the width of the bow wave in a plurality of first images meets the second sliding condition based on the first change data, the change of the bow wave width during the monitoring time period is taken into account, so as to make the result of determining whether the second sliding condition is met more accurate.

[0076] Optionally, step 702 above includes the following specific processing: dividing the monitoring time period into multiple consecutive unit time periods, wherein each unit time period has the same duration, and the duration of each unit time period can be set according to actual needs, such as 1s, 0.5s, or 0.06s, etc., which is not limited in this embodiment; determining the feature value corresponding to each unit time period based on the first change data, wherein the feature value corresponding to each unit time period is used to indicate the bow wave width change corresponding to that unit time period, that is, the larger the bow wave width change of any unit time period in the first change data, the larger the feature value corresponding to that unit time period, and the smaller the bow wave width change of any unit time period in the first change data, the smaller the feature value corresponding to that unit time period; determining whether the bow wave width in multiple first images meets the second sliding condition based on the feature values ​​corresponding to multiple unit time periods.

[0077] In one example, the first change data is a curve showing the change in the width of the bow wave in the first image over the monitoring period as the time of first image acquisition changes. Based on this, after dividing the unit time into multiple consecutive unit time periods, for each unit time period, multiple sampling points can be taken in a relatively dispersed manner from the part of the first change data corresponding to that unit time period. The variance of the width represented by the multiple sampling points is determined as the feature value corresponding to that unit time period. Then, based on the feature value corresponding to each unit time period, it is determined whether the width of the bow wave in the multiple first images meets the second sliding condition.

[0078] In another example, the first change data is a curve showing the change in the width of the bow wave in the first image over the monitoring period as the time of first image acquisition changes. Based on this, after dividing the unit time into multiple consecutive unit time periods, for each unit time period, the difference between the maximum and minimum values ​​of the part of the first change data corresponding to that unit time period can be determined as the feature value corresponding to that unit time period. Then, based on the feature value corresponding to each unit time period, it is determined whether the width of the bow wave in multiple first images meets the second sliding condition.

[0079] In this embodiment of the application, when determining whether the width of the bow wave in multiple first images meets the second sliding condition based on the first change data, the changes in the width of the bow wave within each unit time period are taken into account, that is, the overall changes in the width of the bow wave within the monitoring time period are taken into account, so as to make the result of determining whether the second sliding condition is met more accurate.

[0080] Optionally, the above-mentioned determination of whether the width of the bow wave in multiple first images meets the second sliding condition based on the feature values ​​corresponding to multiple unit time periods includes the following specific processing: determining whether a target time period exists within the monitoring time period based on the feature values ​​corresponding to multiple unit time periods, wherein the target time period includes a consecutive target number of unit time periods, and the sum of the feature values ​​corresponding to the target number of unit time periods exceeds a first threshold; if a target time period exists within the monitoring time period, and the sum of the feature values ​​corresponding to the unit time periods before the target time period is less than a second threshold, and the width of the third bow wave determined based on at least a portion of the first change data after the target time period is less than the second width threshold, then it is determined that the width of the bow wave in multiple first images meets the second sliding condition.

[0081] The target quantity, the first threshold, and the second threshold can all be set according to actual needs. The first threshold can be positively correlated with the target quantity, and the second threshold can be positively correlated with the quantity of a unit time period before the target time period. In this embodiment, the specific values ​​of the target quantity, the first threshold, and the second threshold are not limited.

[0082] In one specific implementation, when determining whether the width of the bow wave in multiple first images meets the second sliding condition based on the feature values ​​of multiple unit time periods, it can be determined whether a target time period exists within the monitoring time period. If it does, it indicates that there is a first part in the first change data where the indicated width changes drastically. Then, a second threshold can be determined based on the number of unit time periods before the target time period, and it can be determined whether the sum of the feature values ​​corresponding to the unit time periods before the target time period is less than the second threshold. If so, it indicates that there is a second part in the first change data where the indicated width is relatively stable before the first part. Furthermore, the third bow wave width can be determined based on the part of the first change data where the indicated width is relatively stable after the target time period (for example, if the indicated width of the part of the first change data where the indicated width is relatively stable after the target time period is approximately 5mm, then the third bow wave width...). The width of the third bow wave is determined to be less than the second width threshold (the second width threshold can be set according to the actual situation, for example, the second width threshold can be equal to the first width threshold, which is not limited in the comparison of the embodiments of this application). If so, it means that there is a third part with a stable and smaller width after the first part in the first change data. Therefore, if there is a target time period in the monitoring time period, and the sum of the feature values ​​corresponding to the unit time period before the target time period is less than the second threshold, and the width of the third bow wave determined according to at least part of the first change data after the target time period is less than the second width threshold, it means that the bow wave width indicated by the first change data is first stable, then changes drastically, and then stabilizes in a smaller state. Then, it can be determined that the width of the bow wave in the multiple first images meets the second sliding condition. Otherwise, it is determined that the width of the bow wave in the multiple first images does not meet the second sliding condition.

[0083] In this embodiment, the bow wave width in multiple first images is determined to meet the second sliding condition when a target time period exists within the monitoring time period, the sum of the feature values ​​corresponding to the unit time period before the target time period is less than a second threshold, and the third bow wave width determined based on at least a portion of the first change data after the target time period is less than the second width threshold. That is, when the first change data satisfies the indicated bow wave width to first stabilize, then change drastically, and then stabilize near a smaller value, the bow wave width in multiple first images is determined to meet the second sliding condition. Compared to only considering the change in bow wave width after sliding, this embodiment takes into account the change in bow wave width before and after sliding, which can make the result of determining whether the second sliding condition is met more accurate.

[0084] Figure 8 This is a flowchart illustrating the determination of whether the second sliding condition is met, according to yet another embodiment of this application. Figure 8As shown, based on the fact that the at least one first image is a plurality of first images acquired by the image acquisition device during the monitoring period, determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data can include the following steps:

[0085] Step 801: During the chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, acquire multiple second images acquired by the image acquisition device during the control time period when the wafer does not slip relative to the polishing head.

[0086] Step 802: Determine the second change data based on multiple second images.

[0087] Step 803: Determine the first change data based on multiple first images.

[0088] Step 804: Compare the second change data with the first change data to determine whether the width of the bow wave in the multiple first images meets the second slider condition.

[0089] In a specific example, both the first and second change data can be curves. Based on this, it can be determined whether the curve similarity between the second and first change data exceeds a similarity threshold. If it does, it indicates that the difference between the second and first change data is large, that is, the difference between the actual bow wave width change and the calibrated bow wave width change is large. In this case, it can be determined that the bow wave width in multiple first images meets the second sliding condition. Otherwise, it indicates that the difference between the second and first change data is small, that is, the difference between the actual and calibrated bow wave width change is small. In this case, it can be determined that the bow wave width in multiple first images does not meet the second sliding condition. The similarity threshold can be set according to actual needs, such as 80%-90%, etc. This application embodiment does not limit this.

[0090] In this embodiment, the width of the bow wave in multiple first images is determined by comparing the second change data and the first change data to see if it meets the second sliding condition. Compared with directly performing logical judgment on the first change data to determine whether the width of the bow wave in multiple first images meets the second sliding condition, this embodiment can reduce the process of designing the judgment logic and the process of verifying and adjusting the designed judgment logic. Therefore, while making the result of determining whether it meets the second sliding condition more accurate, it can also achieve a simpler way to determine whether it meets the second sliding condition.

[0091] Figure 9 This is a flowchart illustrating the determination of whether the second sliding condition is met in another embodiment of this application. Figure 9As shown, based on the fact that at least one first image is a plurality of first images acquired by an image acquisition device within a monitoring time period, and based on the fact that the first change data is a change curve, determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data can include the following steps:

[0092] Step 901: Determine the change curve in the coordinate system based on multiple first images.

[0093] Step 902: After converting the change curve to the time domain and performing a Fourier transform, the transformation result is obtained.

[0094] Step 903: Obtain the superimposed waveforms from the transformation results.

[0095] Step 904: If the peak value of the waveform with the largest peak value among multiple waveforms is less than the first peak value, and the peak value of the waveform with the smallest peak value among multiple waveforms is less than the second peak value, then it is determined that the width of the bow wave in the multiple first images meets the second slider condition, wherein the first peak value is greater than the second peak value.

[0096] The specific values ​​of the first peak and the second peak can be set according to actual needs. This application embodiment does not limit this. For example, the first peak is equal to 10mm and the second peak is equal to 5mm.

[0097] In one specific implementation, the width of the bow wave in multiple first images is fitted to obtain a change curve in a coordinate system. The vertical axis of the coordinate system indicates the width of the bow wave in the first image, and the horizontal axis indicates the time when the image acquisition device acquired the first image. After obtaining the change curve, the change curve is converted to the time domain and then subjected to Fourier transform to obtain the transformation result. Multiple superimposed waveforms are then extracted from the transformation result. If the peak value of the waveform with the largest peak value among the multiple waveforms is less than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is less than the second peak value, then it is determined that the width of the bow wave in the multiple first images meets the second slider condition; otherwise, it is determined that the width of the bow wave in the multiple first images does not meet the second slider condition.

[0098] In this embodiment of the application, by transforming the change curve determined based on the width of the bow wave in multiple first images, a transformation result can be obtained. Based on the transformation result, it can be determined whether the width of the bow wave in multiple first images meets the second slider condition. This eliminates the need to obtain more curves and facilitates operation.

[0099] In one possible implementation, the wafer monitoring method for metal CMP also includes the following specific processing:

[0100] If it is determined that the wafer has slipped relative to the polishing head, the polishing anomaly can be recorded, and the chemical mechanical polishing process can be terminated.

[0101] In one possible implementation, the wafer monitoring method for metal CMP also includes the following specific processing:

[0102] During the chemical mechanical polishing (CMP) process of the metal layer of a wafer, the wafer signal collected by the eddy current sensor when it is in a direction perpendicular to the polishing pad and is relative to the wafer is used to determine whether the time end point of the CMP process has been reached; if the time end point of the CMP process has been reached, the CMP process is terminated.

[0103] In one specific implementation, during the chemical mechanical polishing of the metal layer of a wafer by a CMP device, it can be determined whether the signal strength of the wafer signal is equal to or less than the target signal strength. If so, it is determined that the current time has reached the end point of the chemical mechanical polishing time.

[0104] In the embodiments of this application, the chemical mechanical polishing is automatically terminated by a wafer signal, reducing the possibility of over-polishing or under-polishing of the wafer.

[0105] In one possible implementation, during the chemical mechanical polishing of the wafer's metal layers by the CMP equipment, the time when the image acquisition unit acquires the first image is the same as the time when the eddy current sensor begins acquiring wafer signals.

[0106] Therefore, during the chemical mechanical polishing of the metal layer of the wafer by CMP equipment, the acquisition of the first image and the acquisition of the wafer signal start almost simultaneously. This can minimize the occurrence of situations where the acquisition of the first image starts too early or the acquisition of the wafer signal starts too early, thereby reducing the waste of resources such as equipment, manpower, or electricity.

[0107] This application also provides a wafer monitoring method for non-metallic CMP. This wafer monitoring method for non-metallic CMP can be applied to CMP equipment, etc., and this application does not limit it.

[0108] The difference from the above embodiments is that the CMP equipment in this embodiment includes a drive unit (e.g., a motor) for controlling the rotation of the polishing pad or polishing head. During the chemical mechanical polishing process, the friction between the wafer and the polishing pad will change. At this time, the drive unit will automatically adjust its own torque so that the polishing pad or polishing head it controls can maintain a relatively constant rotation speed. Thus, at least one torque value of the drive unit can be measured to determine the slip. The controller is used to execute the wafer monitoring method for non-metallic CMP.

[0109] The following describes in detail the wafer monitoring method for non-metallic CMP through several embodiments.

[0110] Figure 10 This is a flowchart of a wafer monitoring method for non-metallic CMP according to one embodiment of this application. Figure 10 As shown, the wafer monitoring method for non-metallic CMP includes the following steps:

[0111] Step 1001: During the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, acquire at least one first image acquired by the image acquisition device, and at least one torque value of the drive component.

[0112] In one specific embodiment, during the chemical mechanical polishing (CMP) process of a wafer, an image acquisition device can be controlled to periodically acquire images of the bow wave near the bottom edge of the polishing head on the polishing pad, and all acquired images are used as the first image. The torque value of the driving component can also be periodically acquired. In this embodiment, the image acquisition period of the image acquisition device is not limited; for example, the image acquisition device can be controlled to acquire the first image at a shutter speed of 0.02s and an image acquisition frequency of 5Hz. Similarly, the period for acquiring the torque value of the driving component is not limited.

[0113] Step 1002: Determine whether the wafer has slipped relative to the polishing head based on the width of the bow wave in at least one first image and at least one torque value.

[0114] During chemical mechanical polishing (CMP), whether the wafer slips directly affects the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer is not slipping, the polishing head holds the wafer against the polishing pad, and a liquid film of polishing fluid exists between the wafer and the polishing pad. In this case, the width of the bow wave in the first image is stable around a first value. When the wafer slips, the space below the polishing head changes abruptly, and the polishing fluid switches from one steady state to another, causing the width of the bow wave in the first image to change, for example, stabilizing around a second value, because the wafer slips out from under the polishing head. Afterwards, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the wafer pressure between the polishing head and the polishing pad decreases, so the flow rate of the polishing fluid between the polishing head and the polishing pad increases, and the amount of polishing fluid accumulated on the polishing pad near the bottom edge of the polishing head decreases. Therefore, compared with the first image acquired when the wafer is not slid, the width of the bow wave in the first image acquired when the wafer is slid is generally smaller, that is, the second value is generally smaller than the first value. For example, the first value is 8mm and the second value is 5mm, or the first value is 12mm and the second value is 8mm, etc.

[0115] It should be noted that during chemical mechanical polishing, due to the inherent volatility of the flowing polishing fluid and the reciprocating movement of the polishing head along the radial direction of the polishing pad, the width of the bow wave will fluctuate significantly and regularly, regardless of whether the wafer is sliding. In addition, the width of the bow wave will stabilize around different values ​​before and after wafer sliding. Therefore, the first and second values ​​mentioned above are approximate values ​​of the bow wave width in the first image acquired when the bow wave is relatively stable.

[0116] In chemical mechanical polishing (CMP), whether the wafer slips directly affects the torque value of the drive unit. Specifically, when the wafer is not slipping, the polishing head presses the wafer against the polishing pad. At this time, the friction between the wafer and the polishing pad is relatively large, resulting in a larger torque value for the drive unit. When the wafer slips, the wafer detaches from the polishing head. At this time, the polishing head and the polishing pad are not in contact or are in contact but the friction is relatively small, resulting in a smaller torque value for the drive unit. Therefore, the torque value of the drive unit when the wafer slips is generally smaller than the torque value when the wafer is not slipping.

[0117] Based on this, in one specific embodiment, after acquiring at least one first image and at least one torque value, the width of the bow wave in each first image can be determined. When the width of the bow wave in the acquired at least one first image is small and at least some of the torque values ​​in the at least one torque value are small, it can be determined whether the wafer has slipped relative to the polishing head. Otherwise, it is determined that the wafer has not slipped relative to the polishing head, thus realizing the monitoring of wafer slippage.

[0118] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or it can be calculated by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head in the image acquisition area of ​​the image acquisition device. In this embodiment, the specific method for determining the width of the bow wave in the image is not limited.

[0119] In this embodiment, during the chemical mechanical polishing of the non-metallic layer of a wafer using CMP equipment, at least one first image acquired by an image acquisition device and at least one torque value of a driving component are obtained. Based on the width of the bow wave in the at least one first image and the at least one torque value, it is determined whether the wafer has slipped relative to the polishing head. Therefore, compared to detecting wafer slippage through the relatively short-lived changes in laser light acquired by an optical sensor, this embodiment detects wafer slippage by measuring the width of the bow wave near the polishing head on the polishing pad and the torque value of the driving component. After wafer slippage occurs, the width of the bow wave remains almost consistently small, and the torque value of the driving component also remains almost consistently small, reducing the possibility of false alarms and missed alarms when monitoring wafer slippage, thus making the monitoring results more accurate.

[0120] Furthermore, when determining whether the wafer has slipped relative to the polishing head, a dual judgment is made based on the width of the bow wave on the polishing pad near the polishing head and the torque value of the drive component, which can make the monitoring results of wafer slipping more accurate.

[0121] The above step 1002 can be implemented in at least the following two ways.

[0122] In one possible implementation, step 1002 includes the following specific processing: if the at least one torque value meets the third sliding condition, and the width of the bow wave in the at least one first image meets the second sliding condition, then it is determined that the wafer has slipped relative to the polishing head; otherwise, it is determined that the wafer has not slipped relative to the polishing head. In this embodiment, compared to the next implementation where, based on the at least one torque value meeting the third sliding condition, it is further determined whether the width of the bow wave in the at least one first image meets the second sliding condition, this embodiment does not limit the order of determining whether the third sliding condition and the second sliding condition are met; both can be performed simultaneously, improving the efficiency of determining whether the wafer has slipped relative to the polishing head.

[0123] In another possible implementation, step 1002 includes the following specific processing: if the at least one torque value meets the third sliding condition, then determine whether the width of the bow wave in the at least one first image meets the second sliding condition; if the width of the bow wave in the at least one first image meets the second sliding condition, then determine that the wafer has slid relative to the polishing head. Specifically, it can be first determined whether the at least one torque value meets the third sliding condition; if the at least one torque value meets the third sliding condition, then determine whether the width of the bow wave in the at least one first image meets the second sliding condition; if yes, then determine that the wafer has slid relative to the polishing head; otherwise, determine that the wafer has not slid relative to the polishing head; if the at least one torque value does not meet the third sliding condition, then determine that the wafer has not slid relative to the polishing head.

[0124] In this embodiment, compared to the previous implementation which did not specify the order of determining whether the third slider condition and the second slider condition are met, this embodiment determines whether the width of the bow wave in the at least one first image meets the second slider condition based on the fact that at least one torque value meets the third slider condition. Thus, if at least one torque value does not meet the third slider condition, it is not necessary to determine whether the width of the bow wave in the at least one first image meets the second slider condition, saving computational resources.

[0125] In one possible implementation, the wafer monitoring method for non-metallic CMP further includes the following processing: determining a target torque value based on at least one torque value; if the target torque value is less than a torque threshold, determining that the at least one torque value meets a third sliding condition.

[0126] In one specific embodiment, the aforementioned at least one torque value can be any total torque value collected during the chemical mechanical polishing (CMP) process of the non-metallic layer of the wafer. Based on this, the last torque value among the aforementioned at least one torque value can be determined as the target torque value, or the average of the last few torque values ​​among the aforementioned at least one torque value can be determined as the target torque value, etc. After determining the target torque value, if the target torque value is less than a torque threshold, it is determined that the aforementioned at least one torque value meets the third sliding condition; otherwise, it is determined that the aforementioned at least one torque value does not meet the third sliding condition. The torque threshold can be set according to actual needs, and this embodiment does not limit it.

[0127] In one possible implementation, an image acquisition device is used to acquire an image of the bow wave on the polishing pad near the target portion of the polishing head, the target portion being the part of the polishing head near the supply arm.

[0128] In one specific embodiment, the image acquisition unit can be located between the liquid supply arm and the polishing head in a direction parallel to the polishing pad. The lens of the image acquisition unit is directed towards the target portion of the polishing pad near the polishing head. As a result, the image acquisition unit can acquire the bow wave as close as possible to the liquid supply arm, thereby acquiring a wider bow wave and a more obvious bow wave, which can make the monitoring results of wafer slip monitoring more accurate.

[0129] Optionally, the image acquisition unit may also be connected to an air jet assembly for cleaning the image acquisition unit, in order to reduce the impact of polishing fluid splashed onto the image acquisition unit on the clarity of the images acquired by the image acquisition unit.

[0130] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing solution for image acquisition. If a fluorescent dye is added to the polishing solution, the chemical mechanical polishing process should be carried out in a closed, light-protected environment, and an ultraviolet lamp should be added to the environment to make the bow waves in the image acquired by the image acquisition device clearer.

[0131] The method for determining whether the width of the bow wave in at least one of the first images meets the second slider condition has been described in the previous embodiment of the wafer monitoring method for metal CMP, and will not be repeated here in the embodiments of this application.

[0132] In one possible implementation, the wafer monitoring method for non-metallic CMP further includes the following specific processing: if it is determined that the wafer has slipped relative to the polishing head, the polishing anomaly can be recorded and the chemical mechanical polishing can be terminated.

[0133] In one possible implementation, the wafer monitoring method for non-metallic CMP further includes the following specific processing: during the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, it is determined whether the time endpoint of chemical mechanical polishing has been reached based on the torque value of the drive component; if the time endpoint of chemical mechanical polishing has been reached, the chemical mechanical polishing is terminated.

[0134] Torque monitoring is suitable for determining the endpoint of chemical mechanical polishing (CMP) of non-metallic layers on wafers, especially for determining the endpoint of CMP of the outermost non-metallic layer among two adjacent non-metallic layers on a wafer. Because the materials of these two non-metallic layers are different, the frictional forces when these two non-metallic layers contact the polishing pad during CMP are also different. Consequently, the torque of the drive component differs significantly when these two non-metallic layers contact the polishing pad during CMP. When the outermost non-metallic layer is polished away, the other non-metallic layer contacts the polishing pad, and the torque value of the drive component increases. Therefore, the endpoint of polishing can be monitored by monitoring the torque.

[0135] Based on this, in one specific embodiment, when the CMP equipment performs mechanical and chemical polishing on the non-metallic layer of the wafer, it is determined whether a first preset time has been reached (the first preset time can be the start time of torque value rise). If so, multiple sets of torque values ​​are continuously collected at preset time intervals (e.g., 1 second). Each set of torque values ​​includes at least one torque value, and the torque average of each set of torque values ​​is obtained. It is determined whether the absolute error between the torque average and the first torque value in the next set of torque values ​​is less than the first preset value (e.g., ±0.05%). If so, the moment when the motor torque value is at its maximum is obtained, and it is determined whether the difference between the torque average values ​​of the two sets of torque values ​​adjacent to the torque average is greater than the second preset value (e.g., 0.1%). If so, it indicates that the non-metallic layer to be polished has been almost polished. At this time, the current time can be determined as the time end point, and the chemical mechanical polishing is ended. In addition, if the difference between the current time and the moment when the motor torque value is at its maximum is greater than the protection time, the chemical mechanical polishing can also be ended.

[0136] In this embodiment, chemical mechanical polishing is automatically terminated by monitoring the torque of the drive component, reducing the possibility of over-polishing or under-polishing of the wafer.

[0137] In one possible implementation, during the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, the time when the image acquisition device acquires the first first image is the same as the time when the first torque value of the drive is acquired.

[0138] Therefore, during the chemical mechanical polishing of the non-metallic layer of a wafer by CMP equipment, the acquisition of the first image and the acquisition of the torque value start almost simultaneously. This can minimize the occurrence of situations where the acquisition of the first image starts too early or the acquisition of the torque value starts too early, thereby reducing the waste of resources such as equipment, manpower, or electricity.

[0139] This application also provides a wafer monitoring method for chemical mechanical polishing (CMP). This wafer monitoring method for CMP can be applied to CMP equipment, etc., and this application does not limit it.

[0140] It should be noted that the bow wave width is greatly affected by the rotation speed of the polishing disc, the rotation speed of the polishing head, the liquid supply speed of the liquid supply arm, the ratio of polishing liquid, and the image acquisition position during chemical mechanical polishing. Therefore, the time values ​​or bow wave width values ​​in this application are just examples and are not intended to limit the scope of protection of this application. Those skilled in the art can make changes according to the actual process scenario, and all of them are within the scope of protection of this application.

[0141] Figure 1 This is a schematic diagram of a CMP device according to an embodiment of this application. Figure 1As shown, w represents a wafer. CMP equipment is used for chemical mechanical polishing of wafers, specifically for the chemical mechanical polishing of the metal or non-metal layers of the wafer. This CMP equipment includes: a polishing disc 1, a polishing head holder 2, a polishing head 3, a liquid supply arm, an image acquisition device 4 (e.g., a high-speed camera), and a controller. A circular polishing pad 11 is provided on one side of the polishing disc 1. The polishing disc 1 drives the polishing pad 11 to rotate around its axis. The side of the polishing pad 11 away from the polishing disc 1 is the polishing surface. The polishing head holder 2 is connected to the polishing head 3, which is located between the polishing head holder 2 and the polishing pad 11. The polishing head holder 2 drives the polishing head 3 to bring the wafer into contact with the polishing surface. Specifically... The polishing head 3 drives the metal or non-metal layer on the wafer to be polished to abut against the polishing surface, and drives the wafer to rotate relative to the polishing pad 11 around the wafer's axis. It also drives the polishing head 3 to move the wafer back and forth along the radial direction of the polishing surface to perform chemical mechanical polishing on the wafer. The liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing process. The image acquisition device 4 is connected to the polishing head support 2, and the acquisition lens of the image acquisition device 4 is facing the polishing pad 11 near the polishing head 3. The image acquisition device 4 is used to acquire the image of the bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3. The controller is used to execute the wafer monitoring method for chemical mechanical polishing.

[0142] Optionally, both the polishing head 3 and the polishing head support 2 can be cylindrical in shape. The image acquisition device 4 can be detachably or fixedly connected to the bottom edge of the polishing head support 2. During the chemical mechanical polishing process, since the axes of the polishing head support 2, the polishing head 3, and the wafer are all coincident, and the reciprocating movement of the wafer is achieved by external force driving the polishing head support 2 to reciprocate, the polishing head 3 will rotate around the wafer's own axis relative to the image acquisition device 4. However, the relative position between the polishing head 3 and the image acquisition device 4 will not change, so that the image acquisition device 4 can more stably acquire the bow wave image on the polishing pad 11 near the polishing head 3. Specifically, it can more stably acquire the bow wave image on the polishing pad 11 near the bottom edge of the polishing head 3.

[0143] The following describes in detail the wafer monitoring method for chemical mechanical polishing through several embodiments.

[0144] Figure 11 This is a flowchart of a wafer monitoring method for chemical mechanical polishing according to one embodiment of this application. Figure 11 As shown, the wafer monitoring method for chemical mechanical polishing includes the following steps:

[0145] Step 1101: During the chemical mechanical polishing of the wafer by the CMP equipment, acquire at least one first image acquired by the image acquisition device.

[0146] In one specific embodiment, during the chemical mechanical polishing of a wafer using CMP equipment, an image acquisition device can be controlled to periodically acquire images of the bow wave near the bottom edge of the polishing head on the polishing pad, and all acquired images are used as the first image. In this embodiment, the image acquisition period of the image acquisition device is not limited; for example, the image acquisition device can be controlled to acquire the first image at a shutter speed of 0.02s and an image acquisition frequency of 5Hz.

[0147] Step 1102: If the width of the bow wave in at least one of the first images meets the second slip condition, then it is determined that the wafer has slipped relative to the polishing head.

[0148] During chemical mechanical polishing (CMP), whether the wafer slips directly affects the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer is not slipping, the polishing head holds the wafer against the polishing pad, and a liquid film of polishing fluid exists between the wafer and the polishing pad. At this time, the width of the bow wave in the first image is stable near a first value. When the wafer slips, the space below the polishing head changes abruptly, and the polishing fluid switches from one steady state to another, causing a change in the width of the bow wave in the first image. For example, if the width of the bow wave in the first image is stable near a second value, due to the wafer slipping... After sliding out from under the polishing head, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases. The deformation of the polishing pad caused by the wafer pressure between the polishing head and the polishing pad decreases, which increases the flow rate of the polishing fluid between the polishing head and the polishing pad. The amount of polishing fluid accumulated on the polishing pad near the bottom edge of the polishing head decreases. Therefore, compared with the first image acquired when the wafer is not sliding, the width of the bow wave in the first image acquired when the wafer is sliding is generally smaller. That is, the second value is generally smaller than the first value. For example, the first value is 8mm and the second value is 5mm, or the first value is 12mm and the second value is 8mm, etc.

[0149] It should be noted that during chemical mechanical polishing, due to the inherent volatility of the flowing polishing fluid and the reciprocating movement of the polishing head along the radial direction of the polishing pad, the bow wave width will exhibit relatively regular and large fluctuations regardless of whether the wafer is being slid. In addition, the bow wave width will stabilize around different values ​​when the wafer is not being slid and when it is being slid. Therefore, the first and second values ​​mentioned above are approximate values ​​of the bow wave width in the first image acquired when the bow wave is relatively stable.

[0150] Based on this, in one specific embodiment, after acquiring at least one first image, the width of the bow wave in each first image can be determined. When the width of the bow wave in the acquired at least one first image is small (e.g., less than a certain threshold), it is determined that the width of the bow wave in the acquired at least one first image meets the second slip condition, thereby determining that the wafer has slipped relative to the polishing head. Otherwise, it is determined that the width of the bow wave in the acquired at least one first image does not meet the second slip condition, thereby determining that the wafer has not slipped relative to the polishing head, thus realizing the monitoring of wafer slip.

[0151] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or it can be calculated by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head within the image acquisition area of ​​the image acquisition device. In this embodiment, the specific method for determining the width of the bow wave in the image is not limited.

[0152] In this embodiment, during the chemical mechanical polishing (CMP) process of a wafer, at least one first image is acquired by an image acquisition device. If the width of the bow wave in the at least one first image meets the second slip condition, it is determined that the wafer has slipped relative to the polishing head. Therefore, compared to detecting wafer slippage by detecting the relatively short-lived changes in laser light acquired by an optical sensor, this embodiment detects wafer slippage by measuring the width of the bow wave near the polishing head on the polishing pad. When wafer slippage occurs, the width of the aforementioned bow wave remains almost consistently small, ensuring that the width of the bow wave in the at least one first image acquired most of the time during wafer slippage meets the second slip condition. This reduces the possibility of false alarms and missed alarms when monitoring wafer slippage, making the monitoring results more accurate.

[0153] In one possible implementation, an image acquisition device is used to acquire an image of the bow wave on the polishing pad near the target portion of the polishing head, the target portion being the part of the polishing head near the supply arm.

[0154] In one specific embodiment, the image acquisition unit can be located between the liquid supply arm and the polishing head in a direction parallel to the polishing pad. The lens of the image acquisition unit is directed towards the target portion of the polishing pad near the polishing head. As a result, the image acquisition unit can acquire the bow wave as close as possible to the liquid supply arm, thereby acquiring a wider bow wave and a more obvious bow wave, which can make the monitoring results of wafer slip monitoring more accurate.

[0155] Optionally, the image acquisition unit may also be connected to an air jet assembly for cleaning the image acquisition unit, in order to reduce the impact of polishing fluid splashed onto the image acquisition unit on the clarity of the images acquired by the image acquisition unit.

[0156] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing solution for image acquisition. If a fluorescent dye is added to the polishing solution, the chemical mechanical polishing process should be carried out in a closed, light-protected environment, and an ultraviolet lamp should be added to the environment to make the bow waves in the image acquired by the image acquisition device clearer.

[0157] The method for determining whether the width of the bow wave in at least one of the first images meets the second slider condition has been described in the previous embodiment of the wafer monitoring method for metal CMP, and will not be repeated here in the embodiments of this application.

[0158] Corresponding to the above embodiments of wafer monitoring methods for metal CMP, such as Figure 1 As shown, the CMP equipment includes: a polishing disc 1, a polishing head 3, a liquid supply arm, an image acquisition unit 4, an eddy current sensor, and a controller;

[0159] A polishing pad 11 is provided on one side of the polishing disc 1;

[0160] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11 and drive the wafer to move relative to the polishing pad 11 to perform chemical mechanical polishing on the wafer.

[0161] A liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing of the wafer;

[0162] Image acquisition device 4 is used to acquire images of the bow wave formed by the polishing fluid on the polishing pad 11 near the polishing head 3;

[0163] An eddy current sensor is used to acquire wafer signals when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad 11.

[0164] The controller is used to execute the wafer monitoring method described above for metal CMP.

[0165] It should be noted that the CMP device in this embodiment is used to implement the corresponding wafer monitoring method for metal CMP in the foregoing method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0166] Corresponding to the above embodiments of wafer monitoring methods for non-metallic CMP, such as Figure 1 As shown, the CMP equipment includes: a polishing disc 1, a polishing head 3, a liquid supply arm, an image acquisition unit 4, and a controller;

[0167] A polishing pad 11 is provided on one side of the polishing disc 1;

[0168] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11 and drive the wafer to move relative to the polishing pad 11 to perform chemical mechanical polishing on the wafer.

[0169] A liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing of the wafer;

[0170] Image acquisition device 4 is used to acquire images of the bow wave formed by the polishing fluid on the polishing pad 11 near the polishing head 3;

[0171] Drive components are used to control the rotation of the polishing pad or polishing head;

[0172] The controller is used to execute the wafer monitoring method described above for non-metallic CMP.

[0173] In one specific embodiment, the CMP device can be the CMP device described in the above embodiments of the wafer monitoring method for non-metallic CMP, and the controller is used to execute the above wafer monitoring method for non-metallic CMP.

[0174] It should be noted that the CMP device in this embodiment is used to implement the corresponding wafer monitoring method for non-metallic CMP in the aforementioned method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0175] Corresponding to the above embodiments of the wafer monitoring method for chemical mechanical polishing, such as Figure 1 As shown, the CMP equipment includes: a polishing disc 1, a polishing head 3, a liquid supply arm, an image acquisition unit 4, and a controller;

[0176] A polishing pad 11 is provided on one side of the polishing disc 1;

[0177] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11 and drive the wafer to move relative to the polishing pad 11 to perform chemical mechanical polishing on the wafer.

[0178] A liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing of the wafer;

[0179] Image acquisition device 4 is used to acquire images of the bow wave formed by the polishing fluid on the polishing pad 11 near the polishing head 3;

[0180] The controller is used to execute the wafer monitoring method described above for chemical mechanical polishing.

[0181] In one specific embodiment, the CMP device can be the CMP device described in the above embodiments of the wafer monitoring method for chemical mechanical polishing, and the controller is used to execute the above wafer monitoring method for chemical mechanical polishing.

[0182] It should be noted that the CMP equipment in this embodiment is used to implement the corresponding wafer monitoring method for chemical mechanical polishing in the foregoing method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0183] This application also provides a computer-readable storage medium storing instructions for causing a machine to perform wafer monitoring methods as described herein for metal CMP, non-metal CMP, or chemical mechanical polishing. Specifically, a system or apparatus equipped with a storage medium storing software program code that implements the functions of any of the embodiments described above, and causing the computer (or CPU or MPU) of the system or apparatus to read and execute the program code stored in the storage medium.

[0184] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of this application.

[0185] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0186] This application also provides a computer program product, including computer instructions that instruct a computing device to perform any corresponding operation in the above-described plurality of method embodiments.

[0187] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used for training the model, data used for analysis, stored data, displayed data, etc.) involved in the embodiments of this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0188] It should be noted that, depending on the implementation needs, the various components / steps described in the embodiments of this application can be broken down into more components / steps, or two or more components / steps or parts of the operation of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0189] The methods described in the embodiments of this application can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD-ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code downloaded over a network that is originally stored in a remote recording medium or a non-transitory machine-readable medium and will be stored in a local recording medium. Thus, the methods described herein can be processed by software stored on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that the computer, processor, microprocessor controller, or programmable hardware includes storage components (e.g., RAM, ROM, flash memory, etc.) capable of storing or receiving software or computer code that, when accessed and executed by the computer, processor, or hardware, implements the methods described herein. Furthermore, when a general-purpose computer accesses code used to implement the methods shown herein, the execution of the code transforms the general-purpose computer into a dedicated computer for executing the methods shown herein.

[0190] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used for training the model, data used for analysis, stored data, displayed data, etc.) involved in the embodiments of this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0191] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for specific applications, but such implementations should not be considered beyond the scope of the embodiments of this application.

[0192] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A wafer monitoring method for non-metallic CMP, characterized in that, include: During the chemical mechanical polishing of the non-metallic layer of a wafer using a CMP device, at least one first image is acquired by an image acquisition device, and at least one torque value of a driving component is obtained. The CMP device includes a polishing head, a polishing pad, and a liquid supply arm. The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad. The liquid supply arm is used to supply polishing liquid to the polishing surface. The image acquisition device is used to acquire an image of the bow wave formed by the polishing liquid near the polishing head on the polishing pad. The driving component is used to control the rotation of the polishing pad or the polishing head. Based on the at least one torque value, a target torque value is determined; if the target torque value is less than a torque threshold, then the at least one torque value is determined to meet the third slider condition. If the at least one torque value meets the third slider condition, then determine whether the width of the bow wave in the at least one first image meets the second slider condition; If the width of the bow wave in the at least one first image meets the second slip condition, it is determined that the wafer has slipped relative to the polishing head; wherein, a first bow wave width is determined based on the width of the bow wave in the at least one first image, and if the first bow wave width is less than a first width threshold, it is determined that the width of the bow wave in the at least one first image meets the second slip condition. If it is determined that the wafer has slipped relative to the polishing head, the chemical mechanical polishing process is terminated.

2. The method according to claim 1, characterized in that, The method further includes: Based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data, it is determined whether the width of the bow wave in the at least one first image meets the second slip condition. The first bow wave width is the width obtained based on the width of the bow wave in the at least one first image. The first change data is used to indicate the change in the width of the bow wave in the first image as the time of acquisition of the first image is within the monitoring period. The second change data is used to indicate the change in the width of the bow wave in the second image acquired by the image acquisition device as the time of acquisition of the second image is within the control period when the wafer does not slip relative to the polishing head.

3. The method according to claim 2, characterized in that, Determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data includes: The width of the first bow wave is determined based on the width of the bow wave in the at least one first image; If the width of the first bow wave is less than the first width threshold, then it is determined that the width of the bow wave in the at least one first image meets the second slider condition.

4. The method according to claim 3, characterized in that, The method further includes: During the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, at least one third image is acquired by the image acquisition device when the wafer does not slip relative to the polishing head; The width of the second bow wave is determined based on the width of the bow wave in the at least one third image; The first width threshold is determined based on the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

5. The method according to claim 2, characterized in that, The at least one first image is a plurality of first images acquired by the image acquisition device within the monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data includes: The first change data is determined based on the plurality of first images; Based on the first change data, determine whether the width of the bow wave in the plurality of first images meets the second slider condition.

6. The method according to claim 5, characterized in that, The step of determining whether the width of the bow wave in the plurality of first images meets the second slider condition based on the first change data includes: The monitoring time period is divided into multiple consecutive unit time periods, wherein each unit time period has the same duration. Based on the first change data, the characteristic value corresponding to each unit time period is determined, wherein the characteristic value corresponding to the unit time period is used to indicate the bow width change corresponding to the unit time period; Based on the feature values ​​corresponding to the multiple unit time periods, determine whether the width of the bow wave in the multiple first images meets the second slider condition.

7. The method according to claim 6, characterized in that, The step of determining whether the width of the bow wave in the multiple first images meets the second sliding condition based on the feature values ​​corresponding to the multiple unit time periods includes: Based on the feature values ​​corresponding to the multiple unit time periods, it is determined whether there is a target time period within the monitoring time period, wherein the target time period includes a consecutive number of unit time periods, and the sum of the feature values ​​corresponding to the number of unit time periods exceeds a first threshold. If a target time period exists within the monitoring time period, and the sum of the feature values ​​corresponding to the unit time period before the target time period is less than the second threshold, and the third bow wave width determined based on at least a portion of the first change data after the target time period is less than the second width threshold, then it is determined that the width of the bow wave in the plurality of first images meets the second sliding condition.

8. The method according to claim 2, characterized in that, The at least one first image is a plurality of first images acquired by the image acquisition device within the monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data includes: During the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, multiple second images are acquired by the image acquisition device during a control time period in which the wafer does not slip relative to the polishing head. The second change data is determined based on the plurality of second images; The first change data is determined based on the plurality of first images; By comparing the second change data and the first change data, it is determined whether the width of the bow wave in the plurality of first images meets the second slider condition.

9. The method according to claim 2, characterized in that, The at least one first image refers to multiple first images acquired by the image acquisition device within the monitoring time period, and the first change data refers to a change curve; determining whether the width of the bow wave in the at least one first image meets the second slider condition based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data includes: Based on the plurality of first images, the change curve is determined in a coordinate system; After converting the change curve to the time domain and performing a Fourier transform, the transformation result is obtained; Multiple superimposed waveforms are obtained from the transformation result; If the peak value of the waveform with the largest peak value among multiple waveforms is less than the first peak value, and the peak value of the waveform with the smallest peak value among multiple waveforms is less than the second peak value, then it is determined that the width of the bow wave in the multiple first images meets the second slider condition, wherein the first peak value is greater than the second peak value.

10. The method according to claim 1, characterized in that, During the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, the time when the image acquisition device acquires the first first image is the same as the time when the first torque value of the drive component is acquired.

11. A CMP device, characterized in that, include: Polishing disc, polishing head, liquid supply arm, image acquisition unit, drive unit and controller; A polishing pad is provided on one side of the polishing disc; The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad and to drive the wafer to move relative to the polishing pad in order to perform chemical mechanical polishing on the wafer. The liquid supply arm is used to supply polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; The image acquisition device is used to acquire an image of the bow wave formed by the polishing fluid on the polishing pad near the polishing head; The drive component is used to control the rotation of the polishing pad or the polishing head; The controller is configured to perform a wafer monitoring method for non-metallic CMP as described in any one of claims 1-10.

12. A computer storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the wafer monitoring method for non-metallic CMP as described in any one of claims 1-10.

13. A computer program product, characterized in that, Includes computer instructions that instruct a computing device to perform a wafer monitoring method for non-metallic CMP as described in any one of claims 1-10.

Images