Wafer monitoring method for metal CMP, CMP equipment and computer storage medium

Abstract

The embodiment of the invention provides a wafer monitoring method for metal CMP, CMP equipment and a computer storage medium, and the method comprises the steps: obtaining at least one first image collected by an image collector in a process that the CMP equipment carries out the chemical mechanical polishing of a metal layer of a wafer, the CMP equipment comprises a polishing head, a polishing pad and a liquid supply arm, the polishing head is used for driving the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used for providing polishing liquid for the polishing surface, and the polishing pad is used for driving the wafer to abut against the polishing surface of the polishing pad. The image collector is used for collecting images of bow waves formed by the polishing liquid at the position, close to the polishing head, of the polishing pad; and determining whether the wafer slides relative to the polishing head or not according to the width of the bow wave in the at least one first image and the wafer signal. According to the scheme, the monitoring result of monitoring the wafer slip sheet is more accurate.

Description

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

[0002] The embodiments of the present application relate to the technical field of wafer polishing, and in particular, to a wafer monitoring method for metal CMP, a CMP device, and a computer storage medium. Background Art

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

[0004] The CMP device includes a polishing head and a polishing pad. An optical sensor is provided on the polishing head. During the CMP process of the wafer by the CMP device, the polishing head drives the wafer to abut against the polishing pad, and drives the wafer to rotate and translate relative to the polishing pad supplied with polishing liquid on the surface to polish the wafer. The optical sensor is used to monitor whether the wafer has a slip (a slip means that the wafer is separated from the polishing head). For example, when a slip occurs, the wafer slides out from under 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 by the polishing pad to the laser reflected by the wafer. At this time, it can be determined that the wafer has had a slip.

[0005] However, when the wafer has a slip, the light collected by the optical sensor will return to the laser reflected by the polishing pad after the wafer passes through the monitoring optical path of the optical sensor. Furthermore, the time when the light collected by the optical sensor is the laser reflected by the wafer when the wafer has a slip is relatively short, so it is easy to have false alarms and missed alarms during the monitoring of the wafer slip. Therefore, the monitoring result of the wafer slip is relatively inaccurate. Summary of the Invention

[0006] In view of this, the embodiments of the present application provide a wafer monitoring method for metal CMP, a CMP device, and a computer storage medium to at least partially solve the above problems.

[0007] According to the first aspect of the embodiments of the present application, a wafer monitoring method for metal CMP is provided, including: during the chemical mechanical polishing of the metal layer of the wafer by a CMP device, acquiring at least one first image collected by an image collector, and a wafer signal collected by an eddy current sensor when the eddy current sensor faces 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 collector is used to collect an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad; determining whether the wafer has slipped relative to the polishing head according to the width of the bow wave in the at least one first image and the wafer signal.

[0008] According to the second aspect of the embodiments of the present application, a wafer monitoring method for non-metal CMP is provided, including: during the chemical mechanical polishing of the non-metal layer of the wafer by a CMP device, acquiring at least one first image collected by an image collector, 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 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 collector is used to collect an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad, and the driving member is used to control the rotation of the polishing pad or the polishing head; determining whether the wafer has slipped relative to the polishing head according to the width of the bow wave in the at least one first image and the at least one torque value.

[0009] According to the third aspect of the embodiments of the present application, a wafer monitoring method for chemical mechanical polishing is provided, including: during the chemical mechanical polishing of the wafer by a CMP device, acquiring at least one first image collected by an image collector, 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 collector is used to collect 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 the second slipping condition, determining that the wafer has slipped relative to the polishing head.

[0010] According to a fourth aspect of the embodiments of the present application, a CMP device is provided, including: a polishing platen, a polishing head, a liquid supply arm, an image collector, an eddy current sensor, and a controller; a polishing pad is provided on one side of the polishing platen; the polishing head is configured to drive a wafer to abut against the polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is configured to supply polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is configured to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the eddy current sensor is configured to collect a wafer signal when the eddy current sensor faces the wafer in a direction perpendicular to the polishing pad; the controller is configured to execute the method of the first aspect above.

[0011] According to a fifth aspect of the embodiments of the present application, a CMP device is provided, including: a polishing platen, a polishing head, a liquid supply arm, an image collector, a driving member, and a controller; a polishing pad is provided on one side of the polishing platen; the polishing head is configured to drive a wafer to abut against the polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is configured to supply polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is configured to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the driving member is configured to control the rotation of the polishing pad or the polishing head; the controller is configured to execute the method of the second aspect above.

[0012] According to a sixth aspect of the embodiments of the present application, a CMP device is provided, including: a polishing platen, a polishing head, a liquid supply arm, an image collector, and a controller; a polishing pad is provided on one side of the polishing platen; the polishing head is configured to drive a wafer to abut against the polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is configured to supply polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is configured to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the controller is configured to execute the method of the third aspect above.

[0013] According to a seventh aspect of the embodiments of the present application, a computer storage medium is provided, on which a computer program is stored, and the program is executed by a processor to perform the method of the first aspect, the second aspect, or the third aspect above.

[0014] According to an eighth aspect of the embodiments of the present application, a computer program product is provided, including computer instructions, and the computer instructions instruct a computing device to execute the method of the first aspect, the second aspect, or the third aspect above.

[0015] According to the wafer monitoring solution for metal CMP provided by the embodiments of the present application, during the process of chemically mechanical polishing the metal layer of the wafer by the CMP device, at least one first image collected by the image collector is obtained, and the wafer signal collected by the eddy current sensor when the eddy current sensor faces the wafer in the direction perpendicular to the polishing pad is obtained. Then, according to 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. Thus, compared with monitoring the wafer slip by the relatively short change of the laser collected by the optical sensor, in the embodiments of the present application, it is to monitor whether the wafer slips by the width of the bow wave near the polishing head on the polishing pad and the wafer signal. When the wafer slips, the width of the aforementioned bow wave is almost always stable at a relatively small state, and the signal intensity of the wafer signal is basically always stable at 0 after rapidly decreasing to 0, reducing the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring result of monitoring the wafer slip is more accurate. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram of a CMP device according to an embodiment of the present application;

[0018] Figure 2 It is a schematic diagram of a wafer signal according to an embodiment of the present application;

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

[0020] Figure 4 It is a schematic diagram of a signal intensity change curve according to an embodiment of the present application;

[0021] Figure 5 It is a flowchart of determining whether the second slip condition is met according to an embodiment of the present application;

[0022] Figure 6 It is a schematic diagram of a first sub-curve graph and a second sub-curve graph according to an embodiment of the present application;

[0023] Figure 7 It is a flowchart of determining whether the second slip condition is met according to another embodiment of the present application;

[0024] Figure 8 It is a flowchart for determining whether the second slider condition is met in another embodiment of the present application;

[0025] Figure 9 It is a flowchart for determining whether the second slider condition is met in yet another embodiment of the present application;

[0026] Figure 10 It is a flowchart of a wafer monitoring method for non-metallic CMP in an embodiment of the present application;

[0027] Figure 11 It is a flowchart of a wafer monitoring method for chemical mechanical polishing in an embodiment of the present application.

[0028] Explanation of reference numerals:

[0029] 1, polishing platen; 11, polishing pad; 2, polishing head support; 3, polishing head; 4, image collector. Detailed implementation manners

[0030] The embodiment of the present application provides a wafer monitoring method for metal CMP. This wafer monitoring method for metal CMP can be applied to CMP equipment, etc., and the embodiment of the present application does not limit this.

[0031] Figure 1 It is a schematic diagram of a CMP device in an embodiment of the present application. As Figure 1As shown, w is a wafer, and the CMP device is used for chemically mechanical polishing of the wafer, specifically for chemically mechanical polishing of the metal layer of the wafer. The CMP device includes: a polishing platen 1, a polishing head support 2, a polishing head 3, a liquid supply arm, an image collector 4 (such as a high-speed camera, etc.), an eddy current sensor, and a controller; a circular pad-shaped polishing pad 11 is provided on one side of the polishing platen 1. The polishing platen 1 is used to drive the polishing pad 11 to rotate around the axis of the polishing pad 11. The side of the polishing pad 11 away from the polishing platen 1 is the polishing surface; the polishing head support 2 is connected to the polishing head 3. The polishing head 3 is located between the polishing head support 2 and the polishing pad 11. The polishing head support 2 is used to drive the polishing head 3 to press the wafer against the polishing surface, specifically to press the metal layer to be polished on the wafer against the polishing surface, and drive the polishing head 3 to drive the wafer to rotate around the axis of the wafer relative to the polishing pad 11, and also drive the polishing head 3 to drive the wafer to reciprocate along the radial direction of the polishing surface on the polishing surface to perform chemically mechanical polishing on the wafer; the liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemically mechanical polishing of the wafer; the image collector 4 is connected to the polishing head support 2. The collecting lens of the image collector 4 faces the area on the polishing pad 11 close to the polishing head 3. The image collector 4 is used to collect the image of the bow wave formed by the polishing liquid at the area on the polishing pad 11 close to the polishing head 3; the eddy current sensor is arranged in the polishing platen 1. For example, an installation groove for installing the eddy current sensor can be opened on the side of the polishing platen 1 close to the polishing pad 11. During the chemically mechanical polishing process, the eddy current sensor rotates with the polishing platen 1, so that the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad for part of the time during the chemically mechanical polishing process, and the eddy current sensor is not opposite to the wafer in the direction perpendicular to the polishing pad at other times. The eddy current sensor is used to collect the wafer signal when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad; the controller is used to execute the wafer monitoring method for metal CMP.

[0032] Optionally, the outer shapes of the polishing head 3 and the polishing head support 2 can both be set to be cylindrical. The image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head support 2. During the chemically mechanical polishing process, since the axes of the polishing head support 2, the polishing head 3, and the wafer coincide, and the reciprocating movement of the wafer is realized by driving the polishing head support 2 to reciprocate by an external force, the polishing head 3 will rotate around the axis of the wafer itself relative to the image collector 4, but the relative position between the polishing head 3 and the image collector 4 will not change, so that the image collector 4 can stably collect the image of the bow wave at the area on the polishing pad 11 close to the polishing head 3, specifically, can stably collect the image of the bow wave at the area on the polishing pad 11 close to the bottom edge of the polishing head 3.

[0033] It should be noted that, as Figure 2As shown, when the eddy current sensor faces the metal object, an induced magnetic field (effective magnetic field) will be generated on the metal object, enabling the eddy current sensor to collect signals. Furthermore, when the eddy current sensor is opposite the wafer in the direction perpendicular to the polishing pad, the eddy current sensor can collect wafer signals.

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

[0035] Figure 3 It is a flowchart of the wafer monitoring method for metal CMP according to an embodiment of the present application. As Figure 3 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 device, obtain at least one first image collected by the image collector, and when the eddy current sensor is opposite the wafer in the direction perpendicular to the polishing pad, obtain the wafer signal collected by the eddy current sensor.

[0037] In a specific implementation, during the chemical mechanical polishing of the wafer by the CMP device, the image collector can be controlled to periodically collect images of the bow wave near the bottom edge of the polishing head on the polishing pad, and all the collected images are used as the first images. Additionally, when the eddy current sensor is opposite the wafer in the direction perpendicular to the polishing pad, the wafer signal collected by the eddy current sensor can be obtained. Herein, the present application embodiment does not limit the image collection period of the image collector. For example, the image collector can be controlled to collect the first image at a shutter speed of 0.02 s and an image collection frequency of 5 Hz.

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

[0039] During the chemical mechanical polishing process, whether the wafer slips will directly affect the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer does not slip, the polishing head presses the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near the first value. When the wafer slips, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another, causing the width of the bow wave in the first image collected at this time to change, for example, stabilizing near the second value. Since after the wafer slides 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 pressed between the polishing head and the polishing pad decreases, resulting in an increase in the flow rate of the polishing liquid between the polishing head and the polishing pad, and a decrease in the amount of polishing liquid accumulated near the bottom edge of the polishing head on the polishing pad. Therefore, compared with the first image collected when the wafer does not slip, the width of the bow wave in the first image collected when the wafer slips is generally smaller, that is, the second value is generally less than the first value. For example, the first value is 8 mm and the second value is 5 mm, or the first value is 12 mm and the second value is 8 mm, etc.

[0040] It should be noted that during the chemical mechanical polishing process, due to the fact that the flowing polishing liquid itself has certain fluctuations and the polishing head will drive the wafer to reciprocate along the radial direction of the polishing pad, etc., the width of the bow wave will regularly show large fluctuations whether the wafer slips or not. In addition, the width of the bow wave will be stable near different values when the wafer does not slip and when the wafer slips respectively. Therefore, the above-mentioned first value and second value are both approximate values of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0041] During the chemical mechanical polishing process, whether the wafer slips will directly affect the wafer signal. Specifically, when the wafer does not slip, as the chemical mechanical polishing progresses, the metal layer being polished will gradually become thinner until the thickness of the metal layer reaches the requirement, causing the signal intensity of the wafer signal to gradually decrease to a certain value greater than 0. When the wafer slips, the wafer detaches from the polishing head, resulting in the eddy current sensor and the wafer being almost not opposite or opposite for a very short time in the direction perpendicular to the polishing pad. As a result, the eddy current sensor cannot detect the metal layer or can only detect the metal layer for a very short time. Therefore, the signal intensity of the wafer signal will rapidly decrease to 0. Therefore, compared with the wafer signal when the wafer does not slip, the signal intensity of the wafer signal when the wafer slips will decrease to a smaller value faster.

[0042] Based on this, in a specific embodiment, after collecting the above 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 at least one collected first image is small and the signal intensity of the wafer signal decreases rapidly to a small value, 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, realizing the monitoring of wafer slipping.

[0043] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or 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 collector. In the embodiments of the present application, the specific determination method of the width of the bow wave in the image is not limited.

[0044] In the embodiments of the present application, during the chemical mechanical polishing of the metal layer of the wafer by the CMP device, at least one first image collected by the image collector is obtained, and the wafer signal collected by the eddy current sensor when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad is obtained. Then, according to 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. Thus, compared with monitoring wafer slipping through the relatively short-term change of the laser collected by the optical sensor, in the embodiments of the present application, it is through the width of the bow wave near the polishing head on the polishing pad and the wafer signal to monitor whether the wafer slips. When the wafer slips, the width of the foregoing bow wave is almost always stable at a small state, and the signal intensity of the wafer signal is basically always stable at 0 after rapidly decreasing to 0, reducing the possibility of false alarms and missed alarms when monitoring wafer slipping, making the monitoring result of wafer slipping more accurate.

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

[0046] The above step 302 can be implemented by at least the following two implementation manners.

[0047] In a possible implementation manner, the above step 302 includes the following specific processing: If the wafer signal meets the first slip condition and 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.

[0048] In the embodiment of the present application, compared with the next implementation manner in which, on the basis that the wafer signal meets the first 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, in the embodiment of the present application, the order of determining whether the first sliding condition is met and determining whether the second sliding condition is met is not limited, and the two can also be carried out simultaneously, improving the efficiency of determining whether the wafer has slid relative to the polishing head.

[0049] In another possible implementation manner, 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, and if so, 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 the embodiment of the present application, compared with the previous implementation manner in which the order of determining whether the first sliding condition is met and determining whether the second sliding condition is met is not limited, in the embodiment of the present application, on the basis that the wafer signal meets the first 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, and then when the wafer signal does not meet the first sliding condition, there is no need to determine whether the width of the bow wave in the at least one first image meets the second sliding condition, saving computing resources.

[0051] In one possible implementation manner, the wafer monitoring method for metal CMP further includes the following processing: If the signal intensity of the wafer signal is less than the intensity threshold, or the absolute value of the signal intensity slope of the wafer signal is greater than the slope threshold, then determine that the wafer signal meets the first sliding condition, otherwise, determine that the wafer signal does not meet the first sliding condition.

[0052] Among them, both the intensity threshold and the slope threshold can be set according to actual needs, and the embodiment of the present application 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 metal layer reaches the target thickness calibrated in advance. The target thickness is the thickness of the metal layer when chemical mechanical polishing is normally completed and set in advance.

[0053] In a specific example, as Figure 4 shown, Figure 4 the conventional curve inFigure 4 The abnormal curve in is the signal intensity change curve of the wafer signal before and after the wafer slip occurs. It can be seen that the wafer slips around the turning point of the abnormal curve. At any position after the turning point of the abnormal curve, the signal intensity of the wafer signal can satisfy being less than the intensity threshold, or the absolute value of the signal intensity slope of the wafer signal is greater than the slope threshold. Furthermore, it can be determined that the wafer signal corresponding to the abnormal curve meets the first wafer slip condition. However, at any position in this normal curve, the signal intensity of the wafer signal does not satisfy being less than the intensity threshold, nor does the absolute value of the signal intensity slope of the wafer signal satisfy being greater than the slope threshold. Therefore, it can be determined that the wafer signal corresponding to the normal curve does not meet the first wafer slip condition.

[0054] In a possible implementation, the image collector is used to collect an image of the bow wave at the target part on the polishing pad near the polishing head, and the target part is the part of the polishing head close to the liquid supply arm.

[0055] In a specific embodiment, in the direction parallel to the polishing pad, the image collector can be located between the liquid supply arm and the polishing head, and the lens of the image collector faces the target part on the polishing pad near the polishing head. Thus, the image collector can collect the bow wave as close as possible to the position of the liquid supply arm. Furthermore, the width of the collected bow wave is larger, the collected bow wave is more obvious, and it can make the monitoring result of the wafer slip monitoring more accurate.

[0056] Optionally, an air jet assembly for cleaning the image collector can also be connected to the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0057] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for combined collection; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-shielded environment, and an ultraviolet lamp is added to the environment to make the bow wave in the image collected by the image collector clearer.

[0058] The method for determining whether the width of the bow wave in the above at least one first image meets the second wafer slip condition can be as follows: Determine whether the width of the bow wave in the above at least one first image meets the second wafer slip condition according to at least one of the first bow wave width, the first change data, the second change data, and the comparison result of the first change data, where the first bow wave width is the width obtained according to the width of the bow wave in the above at least one first image, the first change data is used to indicate the change situation of the width of the bow wave in the first image with the time when the first image is collected during the monitoring time period, and the second change data is used to indicate the change situation of the width of the bow wave in the second image collected by the image collector with the time when the second image is collected during the control time period when 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 the at least one first image meets the second slider condition. Figure 5 It is a flowchart for determining whether it meets the second slider condition in an embodiment of the present application. As Figure 5 shown, determining whether the width of the bow wave in the at least one first image meets the second slider condition according to at least one of the first bow wave width, the first change data, the second change data, and the comparison result of the first change data may include the following steps:

[0060] Step 501: Determine the first bow wave width according to the width of the bow wave in the at least one first image.

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

[0062] In a specific embodiment, during the chemical mechanical polishing of the metal layer of the wafer by the CMP device, a first curve graph can be drawn according to the width of the bow wave in the collected first image, and the first curve graph is synchronously updated as more first images are collected. The vertical axis of the first curve graph represents the width of the bow wave, and the horizontal axis of the first curve graph represents the duration of collecting the first image. Based on this, a first sub-curve graph corresponding to the monitoring time period is determined in the first curve graph, and a relatively stable part of the width represented is determined in the first sub-curve graph, and then the first bow wave width is determined according to this part; after determining the first bow wave width, if the first bow wave width is less than the first width threshold, it is determined that the width of the bow wave in the at least one first image meets the second slider condition, otherwise, it is determined that the width of the bow wave in the at least one first image does not meet the second slider condition. Among them, the first width threshold can be set according to actual polishing conditions, and it is generally set at about 5 mm - 10 mm. For example, the first width threshold can be set to 5 mm or 8 mm, etc.

[0063] For example, in Figure 6 it, the dotted curve (i.e., Figure 6a) in it is the first sub-curve graph corresponding to the monitoring time period (0s to 20s). The images collected by the image collector during the monitoring time period are the above-mentioned at least one first image. By observing this first sub-curve graph, it can be known that the time periods of 0s to 1s, 2s to 6s, 8s to 12s, 13s to 17s, and 19s to 20s in the detection time period are all parts with relatively stable widths shown in the first sub-curve graph. It can be clearly seen from the graph that the widths represented by this part are all about 5mm. Therefore, it can be determined that the first bow wave width is 5mm. Then, according to the fact that the first bow wave width 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 slider condition.

[0064] In the embodiment of the present application, when the first bow wave width determined according to the width of the bow wave in the above-mentioned at least one first image is small enough, it can be determined that the width of the bow wave in the above-mentioned at least one first image meets the second slider condition, which can make the judgment logic relatively simple and save computing 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 device, obtaining at least one third image collected by the image collector when the wafer does not undergo slider relative to the polishing head; determining the second bow wave width according to the width of the bow wave in the above-mentioned at least one third image; determining the first width threshold according to the second bow wave width, where the first width threshold is less than or equal to the second bow wave width.

[0066] In a specific embodiment, during the chemical mechanical polishing of the metal layer of the wafer by the CMP device, when the wafer does not undergo slider relative to the polishing head, a second curve graph can be drawn according to the width of the bow wave in the collected third image, and this second curve graph is synchronously updated as more third images are collected. Based on this, the vertical axis of the second curve graph represents the width of the bow wave, the horizontal axis of the second curve graph represents the duration of collecting the third image. Determine the second sub-curve graph corresponding to the control time period in the second curve graph, and determine the part with relatively stable width shown in the second sub-curve graph, and then determine the second bow wave width according to this part; after determining the second bow wave width, a value less than or equal to this second bow wave width can be used as the first width threshold.

[0067] For example, in Figure 6 the solid curve (i.e., Figure 6In b) of , it is the second sub-curve graph. The images captured by the image collector during the comparison time period are the above-mentioned at least one third image. By observing this second sub-curve graph, it can be known that from 0s to 1s, 3s to 6s, 8s to 12s, 14s to 17s, and 19s to 20s in the detection time period are all parts with relatively stable widths represented in the second sub-curve graph. It can be clearly seen from the graph that the widths represented by this part are all about 8mm. Therefore, it can be determined that the width of the second bow wave is 8mm. Then, according to the first width threshold being 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 the embodiment of the present application, the first width threshold being less than or equal to the width of the second bow wave can make the width of the first bow wave less than the first width threshold also less than the width of the second bow wave. Since the width of the bow wave is generally stable at less than the width of the second bow wave when the wafer slides, therefore, when the width of the first bow wave is less than the width of the second bow wave, determining that the above-mentioned at least one first image meets the second sliding condition can make the result of determining whether it meets the second sliding condition more accurate.

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

[0070] Figure 7 It is a flowchart for determining whether it meets the second sliding condition in another embodiment of the present application. As Figure 7 shown, based on the above-mentioned at least one first image being multiple first images captured by the image collector during the monitoring time period, determining whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data, and the comparison result of the first change data can include the following steps:

[0071] Step 701: Determine the first change data according to multiple first images.

[0072] Step 702: Determine whether the width of the bow wave in multiple first images meets the second sliding condition according to the first change data.

[0073] Among them, the first change data can be a curve graph, a mapping function, a mapping table, etc., and the embodiment of the present application does not limit this.

[0074] In a specific embodiment, the first change data can be a curve graph of the width of the bow wave in the first image changing with the time when the first image is captured during the monitoring time period. For example Figure 6For the dashed curve in [the figure], according to the first variation data, the overall variation of the width of the bow wave in the first image acquired by the image collector during the monitoring time period can be determined. Based on this, it can be determined whether the width of the bow wave in multiple first images meets the second sliding piece condition.

[0075] In the embodiments of the present application, when determining whether the width of the bow wave in multiple first images meets the second sliding piece condition according to the first variation data, the variation of the width of the bow wave during the monitoring time period is considered, so that the result of determining whether it meets the second sliding piece condition is more accurate.

[0076] Optionally, the above step 702 includes the following specific processing: The monitoring time period is divided into multiple consecutive unit time periods, where the duration of each unit time period is the same, and the duration of the unit time period can be set according to actual needs, such as 1 s, 0.5 s, or 0.06 s, etc., and the embodiments of the present application do not limit this; According to the first variation data, the characteristic value corresponding to each unit time period is determined, where the characteristic value corresponding to the unit time period is used to indicate the variation amount of the bow wave width corresponding to the unit time period, that is, the greater the variation amount of the bow wave width in any unit time period in the first variation data, the greater the characteristic value corresponding to the unit time period, and the smaller the variation amount of the bow wave width in any unit time period in the first variation data, the smaller the characteristic value corresponding to the unit time period; According to the characteristic values corresponding to multiple unit time periods, it is determined whether the width of the bow wave in multiple first images meets the second sliding piece condition.

[0077] In an example, the first variation data is a curve graph of the width of the bow wave in the first image changing with the time when the first image is acquired during the monitoring time period. Based on this, after dividing the unit time into multiple consecutive unit time periods, for each unit time period, multiple sampling points can be randomly selected from the part corresponding to the unit time period in the first variation data, and the variance of the widths represented by the multiple sampling points is determined as the characteristic value corresponding to the unit time period, and then according to the characteristic 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 piece condition.

[0078] In another example, the first variation data is a curve graph of the width of the bow wave in the first image changing with the time when the first image is acquired during the monitoring time period. Based on this, after dividing the unit time into multiple consecutive unit time periods, for each unit time period, the difference between the maximum value and the minimum value of the part corresponding to the unit time period in the first variation data can be determined as the characteristic value corresponding to the unit time period, and then according to the characteristic 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 piece condition.

[0079] In the embodiment of the present application, when determining whether the width of the bow wave in multiple first images meets the second sliding piece condition according to the first change data, the change of the width of the bow wave in each unit time period is considered, that is, the overall change of the width of the bow wave in the monitoring time period is considered, so as to make the result of determining whether it meets the second sliding piece condition more accurate.

[0080] Optionally, determining whether the width of the bow wave in multiple first images meets the second sliding piece condition according to the characteristic values corresponding to multiple unit time periods includes the following specific processing: determining whether there is a target time period in the monitoring time period according to the characteristic values corresponding to multiple unit time periods, where the target time period includes a continuous target number of unit time periods, and the sum of the characteristic values corresponding to the target number of unit time periods exceeds the first threshold; if there is a target time period in the monitoring time period, and the sum of the characteristic 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 according to at least part of the first change data after the target time period is less than the second width threshold, it is determined that the width of the bow wave in multiple first images meets the second sliding piece condition.

[0081] Among them, the target number, 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 number, and the second threshold is positively correlated with the number of unit time periods before the target time period. The specific values of the target number, the first threshold, and the second threshold are not limited in the embodiment of the present application.

[0082] In a specific embodiment, when determining whether the width of the bow wave in multiple first images meets the second sliding vane condition according to the characteristic values of multiple unit time periods, it is possible to determine whether there is a target time period within the monitoring time period. If so, it indicates that there is a first part in the first change data that indicates a drastic change in the width. Furthermore, the second threshold can be determined according to the number of unit time periods before the target time period, and it can be determined whether the sum of the characteristic 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 before the first part that indicates a relatively stable width. The third bow wave width can also be determined according to the relatively stable part of the width indicated in the first change data after the target time period (for example, for the relatively stable part of the width indicated in the first change data after the target time period, if the width indicated by this part is about 5 mm, then the third bow wave width is equal to 5 mm), and it can be determined whether the third bow wave width is 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, and the embodiments of the present application do not make a limitation on this comparison). If so, it indicates that there is a third part in the first change data after the first part that indicates a relatively small and stable width. Therefore, if there is a target time period within the monitoring time period, and the sum of the characteristic values corresponding to the unit time periods before the target time period is less than the second threshold, and the third bow wave width determined according to at least part of the first change data after the target time period is less than the second width threshold, it indicates that the width of the bow wave indicated by the first change data is first stable, then changes drastically, and then stabilizes at a smaller state. Furthermore, at this time, it can be determined that the width of the bow wave in multiple first images meets the second sliding vane condition. Otherwise, it is determined that the width of the bow wave in multiple first images does not meet the second sliding vane condition.

[0083] In the embodiments of the present application, it is determined that the width of the bow wave in multiple first images meets the second sliding vane condition when there is a target time period within the monitoring time period, and the sum of the characteristic values corresponding to the unit time periods before the target time period is less than the second threshold, and the third bow wave width determined according to at least part 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 that the width of the indicated bow wave is first stable, then changes drastically, and then stabilizes near a smaller value, it is determined that the width of the bow wave in multiple first images meets the second sliding vane condition. Compared with only considering the change in the width of the bow wave after the sliding vane, the embodiments of the present application take into account the change in the width of the bow wave before and after the sliding vane, which can make the result of determining whether it meets the second sliding vane condition more accurate.

[0084] Figure 8 It is a flowchart for determining whether it meets the second sliding vane condition in another embodiment of the present application. As Figure 8As shown, based on the above at least one first image being a plurality of first images acquired by an image collector during a monitoring time period, determining whether the width of the bow wave in the above at least one first image meets the second slider condition according to at least one of the first bow wave width, the first change data, the second change data, and the comparison result of the first change data may include the following steps:

[0085] Step 801, during the process of chemical mechanical polishing of the metal layer of the wafer by a CMP device, obtain a plurality of second images acquired by an image collector during a control time period when the wafer does not experience slider relative to the polishing head.

[0086] Step 802, determine the second change data according to the plurality of second images.

[0087] Step 803, determine the first change data according to the plurality of first images.

[0088] Step 804, compare the second change data and the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slider condition.

[0089] In a specific example, both the first change data and the second change data can be curve graphs. Based on this, it can be determined whether the curve similarity between the second change data and the first change data exceeds a similarity threshold. If it exceeds, it means that the gap between the second change data and the first change data is large, that is, the gap between the actual bow wave width change and the calibrated bow wave width change is large. At this time, it can be determined that the width of the bow wave in the plurality of first images meets the second slider condition. Otherwise, it means that the gap between the second change data and the first change data is small, that is, the gap between the actual bow wave width change and the calibrated bow wave width change is small. At this time, it can be determined that the width of the bow wave in the plurality of first images does not meet the second slider condition. Among them, the similarity threshold can be set according to actual needs, such as 80%-90%, etc. The embodiments of the present application do not limit this.

[0090] In the embodiments of the present application, it is determined whether the width of the bow wave in the plurality of first images meets the second slider condition by comparing the second change data and the first change data. Compared with directly making a logical judgment on the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slider condition, the embodiments of the present application 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 slider condition more accurate, it can also achieve a relatively simple determination of whether it meets the second slider condition.

[0091] Figure 9 It is a flowchart of determining whether it meets the second slider condition in another embodiment of the present application. As Figure 9As shown, based on the above at least one first image being a plurality of first images acquired by an image collector during a monitoring time period, and based on the first change data being a change curve, determining whether the width of the bow wave in the at least one first image meets the second slider condition according to at least one of the first bow wave width, the first change data, the second change data, and the comparison result of the first change data may include the following steps:

[0092] Step 901: Determine a change curve in a coordinate system according to the plurality of first images.

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

[0094] Step 903: Obtain a plurality of superimposed waveforms from the transform result.

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

[0096] Among them, the specific values of the first peak value and the second peak value can be set according to actual needs, and the embodiments of the present application do not limit this. For example, the first peak value is equal to 10 mm and the second peak value is equal to 5 mm.

[0097] In a specific implementation manner, fitting the width of the bow wave in the plurality of first images can obtain a change curve in a coordinate system. The vertical axis of the coordinate system can indicate the width of the bow wave in the first image, and the horizontal axis of the coordinate system can indicate the time when the image collector acquires the first image. After obtaining the change curve, convert the change curve to the time domain and then perform a Fourier transform to obtain a transform result, and then extract a plurality of superimposed waveforms from the transform result. If the peak value of the waveform with the largest peak value among the plurality of waveforms is less than the first peak value, and the peak value of the waveform with the smallest peak value among the plurality of waveforms is less than the second peak value, determine that the width of the bow wave in the plurality of first images meets the second slider condition; otherwise, determine that the width of the bow wave in the plurality of first images does not meet the second slider condition.

[0098] In the embodiments of the present application, by transforming the change curve determined according to the width of the bow wave in the plurality of first images, a transform result can be obtained, and then according to the transform result, it can be determined whether the width of the bow wave in the plurality of first images meets the second slider condition, without obtaining more curves, which is convenient for operation.

[0099] In a possible implementation manner, the wafer monitoring method for metal CMP further includes the following specific processing:

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

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

[0102] During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, it is determined whether the time end of the chemical mechanical polishing has been reached based on the wafer signal collected by the eddy current sensor when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad; if the time end of the chemical mechanical polishing has been reached, the chemical mechanical polishing is terminated.

[0103] In a specific embodiment, during the process of CMP equipment performing chemical mechanical polishing on the metal layer of the wafer, 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 time of the chemical mechanical polishing.

[0104] In the embodiment of the present application, chemical mechanical polishing is automatically terminated through a wafer signal, thereby reducing the possibility of over-polishing the wafer or insufficiently polishing the wafer.

[0105] In a possible implementation, during the process of the CMP device performing chemical mechanical polishing on the metal layer of the wafer, the time when the image collector collects the first image is the same as the time when the eddy current sensor starts to collect wafer signals.

[0106] Therefore, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, the acquisition of the first image and the acquisition of the wafer signal start almost at the same time, which can avoid the situation where the acquisition of the first image starts too early than the acquisition of the wafer signal, or the acquisition of the wafer signal starts too early than the acquisition of the first image, thereby reducing the waste of resources such as equipment, manpower or electricity.

[0107] The embodiment of the present application also provides a wafer monitoring method for non-metallic CMP. The wafer monitoring method for non-metallic CMP can be applied to CMP equipment, etc., and the embodiment of the present application is not limited to this.

[0108] The difference from the above-mentioned embodiment is that the CMP equipment in this embodiment includes a driving member (such as a motor, etc.) for controlling the rotation of the polishing pad or the polishing head. During the chemical mechanical polishing process, the friction between the wafer and the polishing pad will change. At this time, the driving member will automatically adjust its own torque so that the polishing pad or the polishing head controlled by it can maintain a relatively constant rotation speed. Therefore, at least one torque value of the driving member can be measured for judging the slide; the controller is used to execute the wafer monitoring method for non-metallic CMP.

[0109] The wafer monitoring method for non-metal CMP is described in detail below through multiple embodiments.

[0110] Figure 10 It is a flowchart of the wafer monitoring method for non-metal CMP according to an embodiment of the present application. As Figure 10 shown, the wafer monitoring method for non-metal CMP includes the following steps:

[0111] Step 1001, during the chemical mechanical polishing of the non-metal layer of the wafer by the CMP equipment, obtain at least one first image collected by the image collector and at least one torque value of the driving member.

[0112] In a specific implementation, during the chemical mechanical polishing of the wafer by the CMP equipment, the image collector can be controlled to periodically collect images of the bow wave near the bottom edge of the polishing head on the polishing pad, and the collected images are all used as the first images. The torque value of the driving member can also be collected periodically. Among them, the present application embodiment does not limit the image collection period of the image collector. For example, the image collector can be controlled to collect the first image at a shutter speed of 0.02 s and an image collection frequency of 5 Hz. The present application embodiment also does not limit the period of collecting the torque value of the driving member.

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

[0114] During the chemical mechanical polishing process, whether the wafer slips will directly affect the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer does not slip, the polishing head presses the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near the first value. When the wafer slips, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another steady state, so that the width of the bow wave in the first image collected at this time changes, for example, it is stable near the second value. Since after the wafer slides out from under the polishing head, other polishing conditions are 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 pressed between the polishing head and the polishing pad decreases, so that the flow rate of the polishing liquid between the polishing head and the polishing pad becomes larger, and the amount of polishing liquid accumulated near the bottom edge of the polishing head on the polishing pad becomes smaller. Therefore, compared with the first image collected when the wafer does not slip, the width of the bow wave in the first image collected when the wafer slips is generally smaller, that is, the second value is generally less than the first value. For example, the first value is 8 mm and the second value is 5 mm, or the first value is 12 mm and the second value is 8 mm, etc.

[0115] It should be noted that during the chemical mechanical polishing process, due to the inherent volatility of the flowing polishing liquid and the reciprocating movement of the polishing head driving the wafer along the radial direction of the polishing pad, the width of the bow wave will fluctuate significantly in a regular pattern regardless of whether the wafer slides. In addition, the width of the bow wave will stabilize around different values before and after the wafer slides. Therefore, both the above-mentioned first value and second value are approximate values of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0116] During the chemical mechanical polishing process, whether the wafer slides will directly affect the torque value of the driving component. Specifically, when the wafer does not slide, the polishing head presses the wafer against the polishing pad, and at this time, the frictional force between the wafer and the polishing pad is relatively large, resulting in a relatively large torque value of the driving component; when the wafer slides, the wafer disengages from the polishing head, and at this time, the polishing head and the polishing pad do not contact or have a relatively small frictional force when they contact each other, resulting in a relatively small torque value of the driving component. Therefore, compared with the torque value of the driving component when the wafer does not slide, the torque value of the driving component when the wafer slides is generally smaller.

[0117] Based on this, in a specific embodiment, after collecting the above-mentioned at least one first image and the above-mentioned 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 at least one of the collected first images is small and at least some of the at least one torque value is small, it can be determined whether the wafer has slid relative to the polishing head; otherwise, it is determined that the wafer has not slid relative to the polishing head, thus realizing the monitoring of wafer sliding.

[0118] Optionally, the width of the bow wave in the image can be obtained by performing binary processing on the image, or 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. The specific determination method of the width of the bow wave in the image in the embodiments of the present application is not limited.

[0119] In the embodiment of the present application, during the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device, at least one first image collected by the image collector and at least one torque value of the driving member are obtained, and then whether the wafer has slipped relative to the polishing head is determined according to the width of the bow wave in the at least one first image and the at least one torque value. Thus, compared with monitoring the wafer slip by the relatively short-term change of the laser collected by the optical sensor, in the embodiment of the present application, whether the wafer slips is monitored by the width of the bow wave near the polishing head on the polishing pad and the torque value of the driving member. After the wafer slips, the width of the foregoing bow wave is almost always stable at a smaller state, and the torque value of the driving member is also almost always smaller, reducing the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring result of monitoring the wafer slip is more accurate.

[0120] Further, when determining whether the wafer has slipped relative to the polishing head, a dual judgment is made through the width of the bow wave near the polishing head on the polishing pad and the torque value of the driving member, which can make the monitoring result of monitoring the wafer slip more accurate.

[0121] The above step 1002 can be implemented by at least the following two implementation manners.

[0122] In a possible implementation manner, the above step 1002 includes the following specific processing: if the at least one torque value meets the third slip condition and 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; otherwise, it is determined that the wafer has not slipped relative to the polishing head. In the embodiment of the present application, compared with the next implementation manner in which, on the basis that the at least one torque value meets the third slip condition, it is further determined whether the width of the bow wave in the at least one first image meets the second slip condition, in the embodiment of the present application, the order of determining whether the third slip condition is met and determining whether the second slip condition is met is not limited, and the two can also be carried out simultaneously, improving the efficiency of determining whether the wafer has slipped relative to the polishing head.

[0123] In another possible implementation, step 1002 described above includes the following specific processing: If at least one of the torque values meets the third slider condition, determine whether the width of the bow wave in at least one of the first images meets the second slider condition; If the width of the bow wave in at least one of the first images meets the second slider condition, determine that the wafer has slided relative to the polishing head. Specifically, it can be first determined whether at least one of the torque values meets the third slider condition; If at least one of the torque values meets the third slider condition, determine whether the width of the bow wave in at least one of the first images meets the second slider condition. If so, determine that the wafer has slided relative to the polishing head, otherwise, determine that the wafer has not slided relative to the polishing head; If at least one of the torque values does not meet the third slider condition, determine that the wafer has not slided relative to the polishing head.

[0124] In the embodiment of the present application, compared with the previous implementation where the order of determining whether to meet the third slider condition and whether to meet the second slider condition is not limited, in the embodiment of the present application, on the basis that at least one of the torque values meets the third slider condition, it is further determined whether the width of the bow wave in at least one of the first images meets the second slider condition. Furthermore, when at least one of the torque values does not meet the third slider condition, there is no need to determine whether the width of the bow wave in at least one of the first images meets the second slider condition, saving computing resources.

[0125] In a possible implementation, the wafer monitoring method for non-metallic CMP further includes the following processing: Determine a target torque value according to at least one torque value; If the target torque value is less than the torque threshold, determine that at least one of the torque values meets the third slider condition.

[0126] In a specific implementation, at least one of the torque values can be all the torque values collected during the chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device. Based on this, the last torque value among at least one of the torque values can be determined as the target torque value, and the average value of the last few torque values among at least one of the torque values can also be determined as the target torque value, etc.; After determining the target torque value, if the target torque value is less than the torque threshold, determine that at least one of the torque values meets the third slider condition, otherwise, determine that at least one of the torque values does not meet the third slider condition. Among them, the torque threshold can be set according to actual needs, and the embodiment of the present application does not limit this.

[0127] In a possible implementation, the image collector is used to collect an image of the bow wave at the target part on the polishing pad close to the polishing head, and the target part is the part of the polishing head close to the liquid supply arm.

[0128] In a specific embodiment, in the direction parallel to the polishing pad, the image collector can be located between the liquid supply arm and the polishing head, and the lens of the image collector faces the target portion on the polishing pad close to the polishing head. Thus, the image collector can collect the bow wave as close as possible to the position of the liquid supply arm, and further, the width of the collected bow wave is larger, the collected bow wave is more obvious, and the monitoring result of monitoring the wafer sliding can be made more accurate.

[0129] Optionally, a jet component for cleaning the image collector can also be connected to the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0130] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for combined collection; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-shielded environment, and an ultraviolet lamp is added to the environment to make the bow wave in the image collected by the image collector clearer.

[0131] The method for determining whether the width of the bow wave in the at least one first image meets the second slide condition has been described in the foregoing embodiments of the wafer monitoring method for metal CMP, and will not be elaborated herein in the embodiments of the present application.

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

[0133] In a possible implementation manner, 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 device, according to the torque value of the driving member, it is determined whether the time end point of the chemical mechanical polishing has been reached; if the time end point of the chemical mechanical polishing has been reached, the chemical mechanical polishing is ended.

[0134] The torque monitoring method is applicable to the end point judgment during the chemical mechanical polishing of the non-metallic layer of the wafer, especially applicable to the end point judgment during the chemical mechanical polishing of the outermost non-metallic layer among two adjacent non-metallic layers of the wafer. Since the materials of these two non-metallic layers are different, the frictional forces between these two non-metallic layers and the polishing pad during the chemical mechanical polishing process are also different. Furthermore, the torque difference of the driving member during the contact between these two non-metallic layers and the polishing pad during the chemical mechanical polishing process is relatively large. When the outermost non-metallic layer is polished and removed, the other non-metallic layer contacts the polishing pad, and the torque value of the driving member will become larger. Thus, the monitoring of the polishing end point can be achieved by monitoring the torque.

[0135] Based on this, in a specific embodiment, when the CMP equipment performs mechanical chemical polishing on the non-metallic layer of the wafer, it is determined whether it enters the first preset moment (the first preset moment can be the moment when the torque value starts to rise). If so, multiple groups of torque values ​​are continuously collected at each preset time interval (for example, 1s), each group of torque values ​​includes at least one torque value, and the torque mean of each group of torque values ​​is obtained, and it is determined whether the absolute error between the torque mean and the first torque value in the next group of torque values ​​is less than the first preset value (for example, ±0.05%). If so, the maximum moment of the motor torque value is obtained, and it is determined whether the difference between the torque mean values ​​of two groups of torque values ​​adjacent to the torque mean value is greater than the second preset value (for example, 0.1%). If so, it means that the non-metallic layer to be polished has almost been polished. At this time, the current time can be determined as the time end point, and the chemical mechanical polishing is terminated. In addition, if the difference between the current time and the maximum moment of the motor torque value is greater than the protection time, the chemical mechanical polishing can also be terminated.

[0136] In the embodiment of the present application, chemical mechanical polishing is automatically terminated by monitoring the torque of the driving member, thereby reducing the possibility of over-polishing the wafer or insufficiently polishing the wafer.

[0137] In a possible implementation, during the process of chemical mechanical polishing of a non-metallic layer of a wafer by a CMP device, the time when the image collector captures the first image is the same as the time when the first torque value of the driving member is acquired.

[0138] Therefore, during the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, the acquisition of the first image and the acquisition of the torque value are started almost at the same time, which can avoid the situation where the acquisition of the first image starts too early than the acquisition of the torque value, or the acquisition of the torque value starts too early than the acquisition of the first image, thereby reducing the waste of resources such as equipment, manpower or electricity.

[0139] The embodiment of the present application also provides a wafer monitoring method for chemical mechanical polishing. The wafer monitoring method for chemical mechanical polishing can be applied to CMP equipment, etc., and the embodiment of the present application is not limited to this.

[0140] It should be noted that the width of the bow wave is greatly affected by the rotation speed of the polishing disk, the rotation speed of the polishing head, the liquid supply speed of the liquid supply arm, the ratio of the polishing liquid, the image acquisition position, etc. during the chemical mechanical polishing process. Therefore, the time values ​​or bow wave width values ​​in this application are all examples and are not used to limit the scope of protection of this application. Technical personnel in this field can make changes according to the actual process scenarios, which are all within the scope of protection of this application.

[0141] Figure 1 Schematic diagram of a CMP device according to an embodiment of the present application. Figure 1As shown, w is a wafer, and the CMP device is used for chemically mechanical polishing of the wafer, specifically for chemically mechanical polishing of the metal layer or non-metal layer of the wafer. The CMP device includes: a polishing platen 1, a polishing head support 2, a polishing head 3, a liquid supply arm, an image collector 4 (such as a high-speed camera, etc.), and a controller; a circular pad-shaped polishing pad 11 is arranged on one side of the polishing platen 1. The polishing platen 1 is used to drive the polishing pad 11 to rotate around the axis of the polishing pad 11. The side of the polishing pad 11 away from the polishing platen 1 is the polishing surface; the polishing head support 2 is connected to the polishing head 3. The polishing head 3 is located between the polishing head support 2 and the polishing pad 11. The polishing head support 2 is used to drive the polishing head 3 to drive the wafer to abut against the polishing surface, specifically to drive the metal layer or non-metal layer to be polished on the wafer to abut against the polishing surface, and drive the polishing head 3 to drive the wafer to rotate around the axis of the wafer relative to the polishing pad 11, and also drive the polishing head 3 to drive the wafer to reciprocate along the radial direction of the polishing surface on the polishing surface to perform chemically mechanical polishing on the wafer; the liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemically mechanical polishing of the wafer; the image collector 4 is connected to the polishing head support 2, and the acquisition lens of the image collector 4 faces the position on the polishing pad 11 close to the polishing head 3. The image collector 4 is used to acquire an image of the bow wave formed by the polishing liquid at the position on the polishing pad 11 close to the polishing head 3; the controller is used to execute the wafer monitoring method for chemically mechanical polishing.

[0142] Optionally, the outer shapes of both the polishing head 3 and the polishing head support 2 can be set to be cylindrical. The image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head support 2. During the chemically mechanical polishing process, since the axes of the polishing head support 2, the polishing head 3, and the wafer coincide, and the reciprocating movement of the wafer is realized by driving the polishing head support 2 to reciprocate by an external force, the polishing head 3 will rotate around the axis of the wafer itself relative to the image collector 4, but the relative position between the polishing head 3 and the image collector 4 will not change, so that the image collector 4 can stably acquire an image of the bow wave at the position on the polishing pad 11 close to the polishing head 3, specifically, can stably acquire an image of the bow wave at the position on the polishing pad 11 close to the bottom edge of the polishing head 3.

[0143] The following will detail the wafer monitoring method for chemically mechanical polishing through multiple embodiments.

[0144] Figure 11 is a flowchart of the wafer monitoring method for chemically mechanical polishing in an embodiment of the present application. As Figure 11 shown, the wafer monitoring method for chemically mechanical polishing includes the following steps:

[0145] Step 1101: During the process of the CMP device performing chemically mechanical polishing on the wafer, obtain at least one first image acquired by the image collector.

[0146] In a specific embodiment, during the chemical mechanical polishing (CMP) of a wafer by a CMP device, an image collector can be controlled to periodically collect images of the bow wave near the bottom edge of the polishing head on the polishing pad, and the collected images are all used as first images. Herein, the embodiment of the present application does not limit the image collection period of the image collector. For example, the image collector can be controlled to collect the first images at a shutter speed of 0.02 s and an image collection frequency of 5 Hz.

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

[0148] During the chemical mechanical polishing process, whether the wafer slides will directly affect the width of the bow wave near the bottom edge of the polishing head on the polishing pad. Specifically, when the wafer does not slide, the polishing head presses the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near a first value. When the wafer slides, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another, causing the width of the bow wave in the first image collected at this time to change. For example, the width of the bow wave in the first image collected at this time is stable near a second value. Since after the wafer slides out from under the polishing head, other polishing conditions are almost unchanged, but the space between the polishing head and the polishing pad increases, the deformation of the polishing pad caused by the wafer pressed between the polishing head and the polishing pad decreases, causing the flow rate of the polishing liquid between the polishing head and the polishing pad to increase, and the amount of polishing liquid accumulated near the bottom edge of the polishing head on the polishing pad to decrease. Therefore, compared with the first image collected when the wafer does not slide, the width of the bow wave in the first image collected when the wafer slides is generally smaller, that is, the second value is generally less than the first value. For example, the first value is 8 mm and the second value is 5 mm, or the first value is 12 mm and the second value is 8 mm, etc.

[0149] It should be noted that during the chemical mechanical polishing process, due to the fact that the flowing polishing liquid itself has certain fluctuations and the polishing head drives the wafer to reciprocate along the radial direction of the polishing pad, etc., the width of the bow wave will regularly show large fluctuations whether the wafer slides or not. In addition, the width of the bow wave will be stable near different values when the wafer does not slide and when the wafer slides. Therefore, the above first value and second value are both approximate values of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0150] Based on this, in a specific embodiment, after collecting the above 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 at least one collected first image is small (for example, less than a certain threshold), it is determined that the width of the bow wave in the above at least one first image meets the second slider condition, and then it is determined that the wafer has slided relative to the polishing head. Otherwise, it is determined that the width of the bow wave in the above at least one first image does not meet the second slider condition, and then it is determined that the wafer has not slided relative to the polishing head, realizing the monitoring of wafer sliding.

[0151] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or 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 collector. In the embodiments of the present application, the specific determination method of the width of the bow wave in the image is not limited.

[0152] In the embodiments of the present application, during the chemical mechanical polishing of the wafer by the CMP device, at least one first image collected by the image collector is obtained. If the width of the bow wave in the above at least one first image meets the second slider condition, it is determined that the wafer has slided relative to the polishing head. Thus, compared with monitoring wafer sliding through the relatively short change of the laser collected by the optical sensor, in the embodiments of the present application, it is to monitor whether the wafer slides by the width of the bow wave near the polishing head on the polishing pad. When the wafer slides, the width of the foregoing bow wave is almost always stable at a small state, so that the width of the bow wave in the at least one first image collected at most times when the wafer slides meets the second slider condition, reducing the possibility of false alarms and missed alarms when monitoring wafer sliding, and making the monitoring result of wafer sliding more accurate.

[0153] In a possible implementation manner, the image collector is used to collect an image of the bow wave at the target part on the polishing pad near the polishing head, and the target part is the part of the polishing head close to the liquid supply arm.

[0154] In a specific embodiment, in the direction parallel to the polishing pad, the image collector can be located between the liquid supply arm and the polishing head, and the lens of the image collector faces the target part on the polishing pad near the polishing head. Thus, the image collector can collect the bow wave as close as possible to the position of the liquid supply arm, and then the width of the collected bow wave is larger and the collected bow wave is more obvious, which can make the monitoring result of wafer sliding more accurate.

[0155] Optionally, an air jet assembly for cleaning the image collector can also be connected to the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0156] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for collection in cooperation; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed and light-shielded environment, and an ultraviolet lamp should be added to the environment so that the bow wave in the image collected by the image collector is clearer.

[0157] The method for determining whether the width of the bow wave in at least one of the above first images meets the second slider condition has been described in the foregoing embodiments of the wafer monitoring method for metal CMP, and will not be elaborated herein in the embodiments of the present application.

[0158] Corresponding to the foregoing embodiments of the wafer monitoring method for metal CMP, as Figure 1 shown, the CMP device includes: a polishing platen 1, a polishing head 3, a liquid supply arm, an image collector 4, an eddy current sensor, and a controller;

[0159] A polishing pad 11 is provided on one side of the polishing platen 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] The liquid supply arm is used to supply a polishing liquid to the polishing pad 11 during the chemical mechanical polishing of the wafer;

[0162] The image collector 4 is used to collect an image of a bow wave formed by the polishing liquid near the polishing head 3 on the polishing pad 11;

[0163] The eddy current sensor is used to collect a wafer signal when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad 11;

[0164] The controller is used to execute the foregoing wafer monitoring method 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 elaborated herein.

[0166] Corresponding to the foregoing embodiments of the wafer monitoring method for non-metal CMP, as Figure 1 shown, the CMP device includes: a polishing platen 1, a polishing head 3, a liquid supply arm, an image collector 4, and a controller;

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

[0168] A polishing head 3, which is used to drive a wafer to abut against the polishing surface of a polishing pad 11 and drive the wafer to move relative to the polishing pad 11 so as to perform chemical mechanical polishing on the wafer;

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

[0170] An image collector 4, which is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3;

[0171] A driving member, which is used to control the rotation of the polishing pad or the polishing head;

[0172] A controller, which is used to execute the above-mentioned wafer monitoring method for non-metallic CMP.

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

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

[0175] Corresponding to the above-mentioned embodiment of the wafer monitoring method for chemical mechanical polishing, as Figure 1 shown, the CMP device includes: a polishing platen 1, a polishing head 3, a liquid supply arm, an image collector 4 and a controller;

[0176] A polishing pad 11 is arranged on one side of the polishing platen 1;

[0177] A polishing head 3, which is used to drive a wafer to abut against the polishing surface of a polishing pad 11 and drive the wafer to move relative to the polishing pad 11 so as to perform chemical mechanical polishing on the wafer;

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

[0179] An image collector 4, which is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3;

[0180] A controller, which is used to execute the above-mentioned wafer monitoring method for chemical mechanical polishing.

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

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

[0183] This application also provides a computer-readable storage medium storing instructions for causing a machine to execute the wafer monitoring method for metal CMP, the wafer monitoring method for non-metal CMP, or the wafer monitoring method for chemical mechanical polishing as described herein. Specifically, a system or device equipped with a storage medium can be provided, on which software program code for implementing the functions of any one of the above embodiments is stored, and the computer (or CPU or MPU) of the system or device is caused to read and execute the program code stored in the storage medium.

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

[0185] Examples of the storage medium for providing the 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, the program code can be downloaded from a server computer via a communication network.

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

[0187] It should be noted that the information related to users (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data for training a model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of this application are all information and data that have been authorized by the users or fully authorized by all parties, and the collection, use, and processing of the relevant data need to comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding operation entrances are provided for users to select authorization or rejection.

[0188] It should be pointed out that, according to the needs of implementation, each component / step described in the embodiments of this application can be split into more components / steps, or two or more components / steps or partial operations of a component / step can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0189] The method according to the embodiments of the present application can be implemented in hardware, firmware, or be implemented 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 be implemented as computer code originally stored in a remote recording medium or a non-transitory machine-readable medium and downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (such as RAM, ROM, flash memory, etc.) that can store or receive software or computer code. When the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0190] It should be noted that the information related to users (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data for training a model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data that have been authorized by the users or fully authorized by all parties. And the collection, use, and processing of the relevant data need to comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding operation entrances are provided for users to select to authorize or refuse.

[0191] Those of ordinary skill in the art can realize that the units and method steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for a specific application, but such implementation should not be considered to exceed the scope of the embodiments of the present application.

[0192] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant technical fields can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The patent protection scope of the embodiments of the present application shall be defined by the claims.

Claims

1. A wafer monitoring method for metal CMP, characterized in that: include: During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, at least one first image acquired by the image collector and a wafer signal acquired by the eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad are acquired, wherein the CMP device comprises 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 provide polishing liquid to the polishing surface, and the image collector is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; If the signal strength of the wafer signal is less than the strength threshold, or the absolute value of the signal strength slope of the wafer signal is greater than the slope threshold, it is determined that the wafer signal meets the first sliding condition; If the wafer signal meets the first slide condition, determining whether the width of the bow wave in the at least one first image meets the second slide 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; if it is determined that the wafer has slipped relative to the polishing head, the chemical mechanical polishing is terminated.

2. The method according to claim 1, characterized in that The method further comprises: Determine whether the width of the bow wave in the at least one first image meets the second sliding condition based on at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data, wherein the first bow wave width is a 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 how the width of the bow wave in the first image changes with the time when the first image is collected during a monitoring time period, and the second change data is used to indicate how the width of the bow wave in the second image acquired by the image acquirer changes with the time when the second image is collected during a control time period when the wafer does not slip relative to the polishing head.

3. The method according to claim 2, characterized in that The determining whether the width of the bow wave in the at least one first image meets the second slide condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first bow wave width based on the width of the bow wave in the at least one first image; 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 slide condition.

4. The method according to claim 3, characterized in that The method further comprises: During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, acquiring at least one third image acquired by the image acquisition device when the wafer does not slip relative to the polishing head; determining a second bow wave width based on the width of the bow wave in the at least one third image; The first width threshold is determined according to 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 collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first change data according to the plurality of first images; It is determined whether the width of the bow wave in the plurality of first images meets the second slide condition according to the first change data.

6. The method according to claim 5, characterized in that The step of determining, according to the first change data, whether the width of the bow wave in the plurality of first images meets the second slide condition comprises: Dividing the monitoring time period into a plurality of continuous unit time periods, wherein the length of each unit time period is the same; determining a characteristic value corresponding to each of the unit time periods according to the first change data, wherein the characteristic value corresponding to the unit time period is used to indicate a change amount of the bow wave width corresponding to the unit time period; It is determined whether the width of the bow waves in the plurality of first images meets the second sliding sheet condition according to the characteristic values ​​corresponding to the plurality of unit time periods.

7. The method according to claim 6, characterized in that The determining, according to the characteristic values ​​corresponding to the plurality of unit time periods, whether the width of the bow waves in the plurality of first images meets the second slide condition comprises: Determining whether there is a target time period within the monitoring time period according to the characteristic values ​​corresponding to the multiple unit time periods, wherein the target time period includes a continuous target number of unit time periods, and the sum of the characteristic 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 characteristic values ​​corresponding to the unit time periods before the target time period is less than a second threshold, and a third bow wave width determined based on at least part of the first change data after the target time period is less than a second width threshold, it is determined that the width of the bow wave in the multiple first images meets the second slide 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 collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, a plurality of second images acquired by the image acquisition device during a control time period in which the wafer does not slip relative to the polishing head; determining the second change data according to the plurality of second images; determining the first change data according to the plurality of first images; The second change data is compared with the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slide condition.

9. 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 collector within a monitoring time period, and 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 sliding condition according to at least one of the first bow wave width, the first change data, the second change data and a comparison result of the first change data comprises: Determining the variation curve in a coordinate system according to the plurality of first images; The change curve is converted into the time domain and subjected to Fourier transformation to obtain a transformation result; Acquire multiple superimposed waveforms from the transformation results; If the peak value of the waveform with the largest peak value among the multiple waveforms is smaller than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is smaller than the second peak value, it is determined that the width of the bow wave in the multiple first images meets the second slide condition, wherein the first peak value is larger than the second peak value.

10. The method according to claim 1, characterized in that During the process of the CMP equipment performing chemical mechanical polishing on the metal layer of the wafer, the time when the image collector collects the first first image is the same as the time when the eddy current sensor starts to collect the wafer signal.

11. A CMP device, characterized in that: include: Polishing disc, polishing head, liquid supply arm, image collector, eddy current sensor 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 drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; The liquid supply arm is used to supply polishing liquid to the polishing pad during chemical mechanical polishing of the wafer; The image collector is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; The eddy current sensor is used to collect wafer signals when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad; The controller is used to execute the wafer monitoring method for metal CMP as described in any one of claims 1-10.

12. A computer storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the wafer monitoring method for metal CMP as described in any one of claims 1 to 10 is implemented.

13. A computer program product, characterized in that The invention comprises computer instructions, wherein the computer instructions instruct a computing device to execute the wafer monitoring method for metal CMP according to any one of claims 1 to 10.

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