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

Abstract

The embodiment of the application provides a wafer monitoring method for metal CMP, a CMP device and a computer storage medium, the method comprising: acquiring at least one first image collected by an image collector during chemical mechanical polishing of a metal layer of a wafer by the CMP device, and acquiring a wafer signal collected by an eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to a polishing pad, wherein the CMP device comprises a polishing head, the polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a polishing surface of the polishing pad, the liquid supply arm is used to provide a 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; and according to a width of the bow wave in the at least one first image and the wafer signal, it is determined whether wafer slip has occurred relative to the polishing head. The scheme can make the monitoring result of wafer slip monitoring more accurate.

Description

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

[0002] 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

[0003] In the wafer manufacturing process, the metal layer on the wafer surface will be subjected to planarization treatment by chemical mechanical polishing (CMP).

[0004] The CMP device includes a polishing head and a polishing pad, and the polishing head is provided with an optical sensor. 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, so as to polish the wafer. The optical sensor is used to monitor whether the wafer slips (slipping refers to the wafer being separated from the polishing head). For example, when the wafer slips, the wafer slides out from the polishing head and passes through the monitoring light 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 slipped.

[0005] However, when the wafer slips, the light collected by the optical sensor after the wafer passes through the monitoring light path of the optical sensor will recover to the laser reflected by the polishing pad, and then the time for the light collected by the optical sensor to be the laser reflected by the wafer when the wafer slips is relatively short. Therefore, false positives and false negatives are prone to occur when monitoring the wafer slip, and thus the monitoring result of the wafer slip is relatively inaccurate. SUMMARY

[0006] Therefore, 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 a first aspect of the embodiments of the present application, a wafer monitoring method for metal CMP is provided, including: obtaining at least one first image collected by an image collector during chemical mechanical polishing of a metal layer of a wafer by a CMP device, and a wafer signal collected by an eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to a polishing pad, wherein the CMP device includes a polishing head, the polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a 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 on the polishing pad close to the polishing head; and determining whether the wafer has slipped relative to the polishing head according to a width of the bow wave in the at least one first image and the wafer signal.

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

[0009] According to a third aspect of the embodiments of the present application, a wafer monitoring method for chemical mechanical polishing is provided, including: obtaining at least one first image collected by an image collector during chemical mechanical polishing of a wafer by a CMP device, 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 a 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 on the polishing pad close to the polishing head; and determining that the wafer has slipped relative to the polishing head if a width of the bow wave in the at least one first image meets a second wafer slip condition.

[0010] According to a fourth aspect of the embodiments of the present application, a CMP device is provided, comprising: a polishing disc, a polishing head, a liquid supply arm, an image collector, an eddy current sensor and a controller; the polishing disc is provided with a polishing pad on one side; the polishing head is used to drive a wafer to abut on a polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to supply polishing liquid to the polishing pad during the chemical mechanical polishing on the wafer; the image collector is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad close to the polishing head; 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; and the controller is used to execute the method of the first aspect.

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

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

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

[0014] According to an eighth aspect of the embodiments of the present application, a computer program product is provided, comprising 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.

[0015] According to the wafer monitoring scheme for metal CMP provided in the embodiments of the present application, at least one first image collected by an image collector is acquired during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, and a wafer signal collected by an eddy current sensor when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad, 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 wafer signal. Thus, compared with the short-term change of the laser collected by the optical sensor, the wafer slip is monitored 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 bow wave is almost always stable at a small state, and the signal strength of the wafer signal is also basically always stable at 0 after the signal strength is rapidly reduced to 0, which reduces the possibility of false alarm and missed alarm when monitoring the wafer slip, so as to make the monitoring result of the wafer slip more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the embodiments of the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

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

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

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

[0020] Figure 4 is a schematic diagram of a signal strength change curve of an embodiment of the present application;

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

[0022] Figure 6 is a schematic diagram of a first subgraph and a second subgraph of an embodiment of the present application;

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

[0024] Figure 8 is a flow chart of determining whether to meet the second sliding sheet condition according to another embodiment of the present application;

[0025] Figure 9 is a flow chart of determining whether to meet the second sliding sheet condition according to another embodiment of the present application;

[0026] Figure 10 is a flow chart of a wafer monitoring method for non-metal CMP according to an embodiment of the present application;

[0027] Figure 11 is a flow chart of a wafer monitoring method for chemical mechanical polishing according to an embodiment of the present application.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] 1, polishing disc; 11, polishing pad; 2, polishing head support; 3, polishing head; 4, image collector. DETAILED DESCRIPTION

[0030] Embodiments of the present application provide a wafer monitoring method for metal CMP, which can be applied to a CMP device and the like, and the present application is not limited thereto.

[0031] Figure 1 is a schematic diagram of a CMP device according to an embodiment of the present application. As shown in FIG. 1, the CMP device includes a polishing disc 11, a polishing pad 12, a polishing head support 2, a polishing head 3, and an image collector 4. Figure 1As shown, w is a wafer, the CMP device is used for chemical mechanical polishing of the wafer, specifically chemical mechanical polishing of a metal layer of the wafer, and the CMP device comprises: a polishing disc 1, a polishing head support 2, a polishing head 3, a liquid supply arm, an image collector 4 (for example, a high-speed camera or the like), an eddy current sensor, and a controller; the polishing disc 1 is provided with a circular pad-shaped polishing pad 11 on one side, the polishing disc 1 is used to drive the polishing pad 11 to rotate around the axis of the polishing pad 11, and the side of the polishing pad 11 away from the polishing disc 1 is a polishing surface; the polishing head support 2 is connected with 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 on the polishing surface, specifically to drive the metal layer to be polished on the wafer to abut on 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 on the polishing surface along the radial direction of the polishing surface, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing of the wafer; the image collector 4 is connected to the polishing head support 2, the collection lens of the image collector 4 faces the polishing pad 11 close to the polishing head 3, and the image collector 4 is used to collect the image of the bow wave formed by the polishing liquid on the polishing pad 11 close to the polishing head 3; the eddy current sensor is arranged in the polishing disc 1, for example, a mounting groove for mounting the eddy current sensor can be formed on the side of the polishing disc 1 close to the polishing pad 11, and during the chemical mechanical polishing, the eddy current sensor rotates with the polishing disc 1, so that part of the time during the chemical mechanical polishing, the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad, and the other time, the eddy current sensor is not opposite to the wafer in the direction perpendicular to the polishing pad, and 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; and the controller is used to execute the wafer monitoring method for metal CMP.

[0032] Optionally, the polishing head 3 and the polishing head support 2 can both be provided in a cylindrical shape, and the image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head support 2, and during the chemical mechanical polishing, since the axis of the polishing head support 2, the axis of the polishing head 3 and the axis of the wafer all coincide, and the reciprocating movement of the wafer is achieved by driving the polishing head support 2 to reciprocate through an external force, therefore the polishing head 3 rotates relative to the image collector 4 around the axis of the wafer itself, but the relative position between the polishing head 3 and the image collector 4 does not change, so that the image collector 4 can more stably collect the image of the bow wave on the polishing pad 11 close to the polishing head 3, specifically, the image collector 4 can more stably collect the image of the bow wave on the polishing pad 11 close to the bottom edge of the polishing head 3.

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

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

[0035] Figure 3 The flowchart of the wafer monitoring method for metal CMP is an embodiment of the present application. As shown, the wafer monitoring method for metal CMP includes the following steps: Figure 3

[0036] Step 301, during chemical mechanical polishing of a metal layer of a 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 is opposite the wafer in a direction perpendicular to a polishing pad.

[0037] In one specific embodiment, during chemical mechanical polishing of a wafer by a CMP device, the image collector can be controlled to periodically collect images of bow waves near the edge of the bottom surface of the polishing head on the polishing pad, and the collected images are all first images. The wafer signal collected by the eddy current sensor when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad can also be acquired. The image collection period of the image collector is not limited in the embodiments of the present application. For example, the image collector can be controlled to collect first images at a shutter speed of 0.02 s and an image collection frequency of 5 Hz.

[0038] Step 302, determining whether a slip has occurred in the wafer relative to the polishing head according to the width of the bow wave in the at least one first image and the wafer signal.

[0039] ​In the process of chemical mechanical polishing, whether the wafer slips or not will directly affect the width of the bow wave on the polishing pad close to the edge of the bottom surface of the polishing head. Specifically, when the wafer does not slip, the polishing head abuts the wafer on 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 around a first value. When the wafer slips, the space below the polishing head changes suddenly, and the polishing liquid changes from one steady state to another. Therefore, the width of the bow wave in the first image collected at this time changes, for example, and is stable around a second value. After the wafer slips out from below the polishing head, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the wafer 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 increases, and the amount of polishing liquid accumulated on the polishing pad close to the edge of the bottom surface of the polishing head decreases. 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 smaller 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, in the process of chemical mechanical polishing, due to the inherent volatility of the flow-based polishing liquid and the reciprocating movement of the wafer along the radial direction of the polishing pad driven by the polishing head, the width of the bow wave will fluctuate regularly regardless of whether the wafer slips or not. In addition, the width of the bow wave will be stable around different values when the wafer does not slip and when the wafer slips. Therefore, the first value and the second value described above are approximate values of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0041] In the process of chemical mechanical polishing, whether the wafer slips or not will directly affect the wafer signal. Specifically, when the wafer does not slip, as the chemical mechanical polishing progresses, the polished metal layer will gradually thin out until the thickness of the metal layer meets the requirements, so that the signal intensity of the wafer signal will gradually decrease to a certain value greater than 0. When the wafer slips, the wafer is separated from the polishing head, so that the eddy current sensor is almost not opposite to the wafer or opposite to the wafer for a very short time in the direction perpendicular to the polishing pad, and thus the eddy current sensor cannot detect the metal layer or detects 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 more quickly to a smaller value.

[0042] Based on this, in one specific embodiment, after the at least one first image and the wafer are collected, the width of the bow wave in each first image can be determined, and when the width of the bow wave in the collected at least one first image is smaller and the signal strength of the wafer signal decreases to a smaller value more quickly, it can be determined whether the wafer has slipped relative to the polishing head, otherwise, it is determined that the wafer has not slipped relative to the polishing head, thereby achieving monitoring of wafer slip.

[0043] Alternatively, 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, which can be the arc length of the polishing head within the image collection area of the image collector. The specific determination method of the width of the bow wave in the image is not limited in the embodiments of the present application.

[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 when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad, the wafer signal collected by the eddy current sensor, and 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 short-lived changes of the laser collected by the optical sensor, in the embodiments of the present application, the width of the bow wave near the polishing head on the polishing pad and the wafer signal are used to monitor whether the wafer has slipped, and when the wafer slips, the width of the aforementioned bow wave is almost always stable at a small state, and after the signal strength of the wafer signal decreases to 0 more quickly, it is also basically always stable at 0, thereby reducing the possibility of false positives and false negatives when monitoring the wafer slip, so as to make the monitoring result of monitoring the wafer slip more accurate.

[0045] Further, when it is determined whether the wafer has slipped relative to the polishing head, the width of the bow wave near the polishing head on the polishing pad and the wafer signal are used for double judgment, which can make the monitoring result of monitoring the wafer slip more accurate.

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

[0047] In one 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, the width of the bow wave in the at least one first image is determined whether it meets the second slide condition on the basis that the wafer signal meets the first slide condition. The present embodiment does not limit the order of determining whether it meets the first slide condition and determining whether it meets the second slide condition, and both can be performed at the same time, which improves the efficiency of determining whether the wafer has occurred slide relative to the polishing head.

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

[0050] In the embodiment of the present application, compared with the previous implementation, the width of the bow wave in the at least one first image is determined whether it meets the second slide condition on the basis that the wafer signal meets the first slide condition. In this way, when the wafer signal does not meet the first slide condition, it is not necessary to determine whether the width of the bow wave in the at least one first image meets the second slide condition, thereby saving computing resources.

[0051] In a possible implementation, the wafer monitoring method for metal CMP further includes the following processing: if the signal intensity of the wafer signal is less than an intensity threshold value, or the absolute value of the signal intensity slope of the wafer signal is greater than a slope threshold value, it is determined that the wafer signal meets the first slide condition, otherwise, it is determined that the wafer signal does not meet the first slide condition.

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

[0053] In a specific example, as shown in FIG. 6, the conventional curve in the wafer signal is the signal intensity change curve of the wafer signal when no slide occurs. Figure 4 Figure 4 In a specific example, as shown in FIG. 6, the conventional curve in the wafer signal is the signal intensity change curve of the wafer signal when no slide occurs.​Figure 4 The abnormal curve in the figure is a signal intensity change curve of the wafer signal before and after the wafer slip, and it can be seen that the wafer slip occurs 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 is less than the intensity threshold, or the absolute value of the slope of the signal intensity of the wafer signal is greater than the slope threshold, and thus it can be determined that the wafer signal corresponding to the abnormal curve meets the first wafer slip condition. At any position in the normal curve, the signal intensity of the wafer signal is not less than the intensity threshold, nor is the absolute value of the slope of the signal intensity of the wafer signal greater than the slope threshold, and thus 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 configured to collect an image of the bow wave at a target portion on the polishing pad close to the polishing head, the target portion being a portion of the polishing head close to the liquid supply arm.

[0055] In a specific embodiment, in a direction parallel to the polishing pad, the image collector can be located between the liquid supply arm and the polishing head, and a lens of the image collector faces the target portion on the polishing pad close to the polishing head. In this way, the image collector can collect a bow wave close to the liquid supply arm, and thus the collected bow wave has a greater width and is more obvious, which can make the monitoring result of wafer slip more accurate.

[0056] Optionally, the image collector can be further connected with a jetting assembly for cleaning the image collector, so as to reduce the influence of the polishing liquid splashed onto the image collector on the definition of the image collected by the image collector.

[0057] Optionally, inert dyes or inert fluorescent dyes can be added to the polishing liquid for cooperation with the collection. If the fluorescent dyes are added to the polishing liquid, the chemical mechanical polishing process should be carried out in a closed and light-proof environment, and an ultraviolet lamp is added to the environment, so that the bow wave in the image collected by the image collector is clearer.

[0058] The manner of determining whether the width of the bow wave in the at least one first image meets the second wafer slip condition can be as follows: determining whether the width of the bow wave in the at least one first image meets the second wafer slip condition according to at least one of a first bow wave width, first change data, second change data and a comparison result of the first change data, wherein the first bow wave width is a width obtained according to the width of the bow wave in the at least one first image, the first change data is used to indicate a change of the width of the bow wave in the first image with time in a monitoring time period, and the second change data is used to indicate a change of the width of the bow wave in a second image collected by the image collector with time in a control time period in which the wafer does not slip relative to the polishing head.

[0059] Based on this, there are at least three specific ways to determine whether the width of the bow wave in the at least one first image meets the second slide condition. Figure 5 is a flowchart of determining whether the second slide condition is met according to an embodiment of the present application. As shown in Figure 5 , the determination of 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 can 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, it is determined that the width of the bow wave in the at least one first image meets the second slide condition.

[0062] In one 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 updated synchronously 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 time length 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 part with a relatively stable width is determined in the first sub-curve graph. Then, the first bow wave width is determined according to the part. After the first bow wave width is determined, 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 slide condition, otherwise, it is determined that the width of the bow wave in the at least one first image does not meet the second slide condition. The first width threshold can be set according to the actual polishing conditions, and is generally set to about 5mm-10mm, for example, the first width threshold can be set to 5mm or 8mm, etc.

[0063] For example, in Figure 6 , the curve of the dashed line (i.e. Figure 6The a) in the figure is a first subgraph corresponding to a monitoring time period (0s to 20s). The images collected by the image collector in the monitoring time period are the at least one first image. By observing the first subgraph, it can be found that 0s to 1s, 2s to 6s, 8s to 12s, 13s to 17s and 19s to 20s in the monitoring time period are relatively stable parts represented by the width of the first subgraph. It can be seen from the figure that the width represented by these parts is about 5mm. Therefore, it can be determined that the first hump width is 5mm. According to the fact that the first hump width is less than the first width threshold (the first width threshold is set to 8mm), it can be determined that the width of the hump in the at least one first image meets the second slide condition.

[0064] In the embodiments of the present application, when the first hump width determined according to the width of the hump in the at least one first image is small enough, it can be determined that the width of the hump in the at least one first image meets the second slide condition. This can make the judgment logic 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, at least one third image collected by the image collector when the wafer does not slide relative to the polishing head is obtained; a second hump width is determined according to the width of the hump in the at least one third image; and a first width threshold is determined according to the second hump width, wherein the first width threshold is less than or equal to the second hump width.

[0066] In one specific embodiment, during the chemical mechanical polishing of the metal layer of the wafer by the CMP device, when the wafer does not slide relative to the polishing head, a second graph can be drawn according to the width of the hump in the collected third image, and the second graph is updated synchronously as more third images are collected. Based on this, the vertical axis of the second graph represents the width of the hump, and the horizontal axis of the second graph represents the time length of collecting the third image. A second subgraph corresponding to a control time period is determined in the second graph, and a relatively stable part represented by the second subgraph is determined. Then, the second hump width is determined according to the part. After the second hump width is determined, a value less than or equal to the second hump width can be used as the first width threshold.

[0067] For example, in the case of Figure 6 In the figure, the solid curve (i.e. Figure 6b) is a second sub-graph, the image collected by the image collector in the control time period is the at least one third image, by observing the second sub-graph, it can be known that 0s to 1s, 3s to 6s, 8s to 12s, 14s to 17s and 19s to 20s in the detection time period are relatively stable parts represented by the width of the second sub-graph, it can be obviously seen from the graph that the width represented by this part is about 8mm, and thus it can be determined that the second bow wave width is 8mm, and according to that the first width threshold is less than or equal to the second bow wave width, it can be determined that the first width threshold is 8mm.

[0068] In the embodiment of the present application, the first width threshold is less than or equal to the second bow wave width, which can make the first bow wave width less than the first width threshold also less than the second bow wave width, and since the width of the bow wave is generally stable at less than the second bow wave width when the wafer is being lapped, determining that the at least one first image meets the second lapping condition when the first bow wave width is less than the second bow wave width can make the result of determining whether the second lapping condition is met more accurate.

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

[0070] Figure 7 is a flowchart of determining whether the second lapping condition is met according to another embodiment of the present application. As shown in Figure 7 Based on that the at least one first image is a plurality of first images collected by the image collector in the monitoring time period, the step of determining whether the width of the bow wave in the at least one first image meets the second lapping 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, determining the first change data according to the plurality of first images.

[0072] Step 702, determining whether the width of the bow wave in the plurality of first images meets the second lapping condition according to the first change data.

[0073] The first change data can be a graph, a mapping function or a mapping table, and the embodiments of the present application do not limit this.

[0074] In a specific embodiment, the first change data can be a graph of the change of the width of the bow wave in the first image with the time when the first image is collected in the monitoring time period, for example Figure 6According to the curve of the dashed line in the first change data, the overall change of the width of the bow wave in the first images collected by the image collector in the monitoring time period can be determined, and based on this, whether the width of the bow wave in the plurality of first images meets the second slide condition can be determined.

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

[0076] Optionally, the step 702 includes the following specific processing: dividing the monitoring time period into a plurality of continuous unit time periods, wherein the lengths of the unit time periods are the same, and the length of the unit time period can be set according to actual needs, for example, 1s, 0.5s or 0.06s, etc., which is not limited in the embodiments of the present application; determining the characteristic value corresponding to each unit time period according to the first change data, wherein the characteristic value corresponding to the unit time period is used to indicate the bow wave width change amount corresponding to the unit time period, that is, the greater the bow wave width change amount of any unit time period in the first change data, the greater the characteristic value corresponding to the unit time period, and the smaller the bow wave width change amount of any unit time period in the first change data, the smaller the characteristic value corresponding to the unit time period; determining whether the width of the bow wave in the plurality of first images meets the second slide condition according to the characteristic values corresponding to the plurality of unit time periods.

[0077] In one example, the first change data is a curve graph of the change of the width of the bow wave in the first image with the time of collecting the first image in the monitoring time period, and based on this, after dividing the unit time into a plurality of continuous unit time periods, for each unit time period, a plurality of sampling points can be taken from the relatively dispersed part corresponding to the unit time period in the first change data, and the variance of the width represented by the plurality of sampling points is determined as the characteristic value corresponding to the unit time period, and then whether the width of the bow wave in the plurality of first images meets the second slide condition is determined according to the characteristic value corresponding to each unit time period.

[0078] In another example, the first change data is a curve graph of the change of the width of the bow wave in the first image with the time of collecting the first image in the monitoring time period, and based on this, after dividing the unit time into a plurality of continuous 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 change data is determined as the characteristic value corresponding to the unit time period, and then whether the width of the bow wave in the plurality of first images meets the second slide condition is determined according to the characteristic value corresponding to each unit time period.

[0079] In the embodiments of the present application, when determining whether the width of the bow wave in the plurality of first images meets the second slide 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 that the result of determining whether the second slide condition is met is more accurate.

[0080] Optionally, the above determining whether the width of the bow wave in the plurality of first images meets the second slide condition according to the feature values corresponding to the plurality of unit time periods comprises the following specific processing: determining whether there is a target time period in the monitoring time period according to the feature values corresponding to the plurality of unit time periods, wherein the target time period comprises a target number of continuous unit time periods, and the sum of the feature values corresponding to the target number of unit time periods exceeds a first threshold value; if there is a target time period in the monitoring time period, the sum of the feature values corresponding to the unit time periods before the target time period is less than a second threshold value, and a third bow wave width determined according to at least part of the first change data after the target time period is less than a second width threshold value, it is determined that the width of the bow wave in the plurality of first images meets the second slide condition.

[0081] Wherein, the target number, the first threshold value and the second threshold value can be set according to actual needs, the first threshold value can be positively correlated with the target number, and the second threshold value is positively correlated with the number of unit time periods before the target time period, and the specific values of the target number, the first threshold value and the second threshold value are not limited in the embodiments of the present application.

[0082] In one specific implementation, when determining whether the width of the bow wave in the plurality of first images meets the second slide condition according to the characteristic values of the plurality of unit time periods, it can be determined whether there is a target time period in the monitoring time period, and if so, it indicates that there is a first part in the first change data indicating a sharp change in width. Then, the second threshold value can be determined according to the number of unit time periods before the target time period, and it is 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 value. If so, it indicates that there is a second part in the first change data before the first part, which indicates that the width is relatively stable. In addition, a third bow wave width can be determined according to the part of the first change data after the target time period indicating that the width is relatively stable (for example, for the part of the first change data after the target time period indicating that the width is relatively stable, the width indicated by this part is about 5mm, and the third bow wave width is equal to 5mm), and it is determined whether the third bow wave width is less than the second width threshold value (the second width threshold value can be set according to actual conditions, for example, the second width threshold value can be equal to the first width threshold value, and the application embodiments are not limited in comparison). If so, it indicates that there is a third part in the first change data after the first part, which indicates that the width is stable and small. Therefore, if there is a target time period in 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 value, 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 value, it indicates that the bow wave width indicated by the first change data is stable first, then changes sharply, and then stabilizes at a smaller state. Therefore, at this time, it can be determined that the width of the bow wave in the plurality of first images meets the second slide condition, otherwise, it is determined that the width of the bow wave in the plurality of first images does not meet the second slide condition.

[0083] In the embodiments of the present application, the width of the bow wave in the plurality of first images is determined to meet the second slide condition when there is a target time period in the monitoring time period, the sum of the characteristic values corresponding to the unit time periods before the target time period is less than the second threshold value, 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 value. That is, when the first change data meets the bow wave width indicated by the first change data first stable, then changes sharply, and then stabilizes around a smaller value, it is determined that the width of the bow wave in the plurality of first images meets the second slide condition. Compared with only considering the change of the bow wave width after the slide, the application embodiments consider the change of the bow wave width before and after the slide, which can make the result of determining whether to meet the second slide condition more accurate.

[0084] Figure 8 is a flowchart of another embodiment of the present application for determining whether to meet the second slide condition. As Figure 8As shown, based on the plurality of first images collected by the image collector in the monitoring time period, the determination of whether the width of the bow wave in the at least one first image meets the second 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 can include the following steps:

[0085] Step 801, in the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, a plurality of second images collected by the image collector in a control time period in which the wafer does not slip relative to the polishing head are obtained.

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

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

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

[0089] In one specific example, the first change data and the second change data can both be a curve diagram, based on which it can be determined whether the curve similarity of the second change data and the first change data exceeds a similarity threshold value, if it does, it means that the actual bow wave width change and the calibrated bow wave width change have a large difference, at this time it can be determined that the width of the bow wave in the plurality of first images meets the second slip condition, otherwise, it means that the actual bow wave width change and the calibrated bow wave width change have a small difference, 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 slip condition, wherein the similarity threshold value can be set according to actual needs, for example, 80%-90% and the like, which is not limited in the embodiment of the present application.

[0090] In the embodiment of the present application, the determination of whether the width of the bow wave in the plurality of first images meets the second slip condition is made 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 slip condition, the embodiment of the present application can reduce the process of designing the judgment logic and the process of verifying and adjusting the designed judgment logic, thus making the result of determining whether it meets the second slip condition more accurate, and also realizing a relatively simple determination of whether it meets the second slip condition.

[0091] Figure 9 is the flow chart of the embodiment of the present application for determining whether it meets the second slip condition. As shown in the figure, Figure 9As shown, based on the at least one first image being a plurality of first images collected by the image collector in the monitoring time period, and based on the first change data being a change curve, 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 can include the following steps:

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

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

[0094] Step 903, obtaining a plurality of superimposed waveforms from the transform result.

[0095] Step 904, if the peak value of the waveform with the largest peak value in the plurality of waveforms is less than a first peak value, and the peak value of the waveform with the smallest peak value in the plurality of waveforms is less than a second peak value, it is determined that the width of the bow wave in the plurality of first images meets the second slide condition, wherein the first peak value is greater than the second peak value.

[0096] 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 one specific embodiment, the width of the bow wave in the plurality of first images is fitted to 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 collects the first image. After obtaining the change curve, the change curve is converted to a time domain and then Fourier transformed to obtain a transform result, and then a plurality of superimposed waveforms are extracted from the transform result. If the peak value of the waveform with the largest peak value in the plurality of waveforms is less than a first peak value, and the peak value of the waveform with the smallest peak value in the plurality of waveforms is less than a second peak value, it is determined that the width of the bow wave in the plurality of first images meets the second slide condition, otherwise, it is determined that the width of the bow wave in the plurality of first images does not meet the second slide 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 slide condition, without obtaining more curves, facilitating operation.

[0099] In one possible implementation, 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 ended.

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

[0102] In the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, whether the time end point of the chemical mechanical polishing is reached is determined according to 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 point of the chemical mechanical polishing is reached, the chemical mechanical polishing is ended.

[0103] In a specific embodiment, in the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, whether the signal strength of the wafer signal is equal to or less than the target signal strength can be determined, and if yes, it is determined that the current time has reached the time end point of the chemical mechanical polishing.

[0104] In the embodiments of the present application, the chemical mechanical polishing is automatically ended through the wafer signal, and the possibility of over-polishing the wafer or insufficient polishing of the wafer is reduced.

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

[0106] Therefore, in the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, the acquisition of the first image and the acquisition of the wafer signal start almost at the same time, and the situation that 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 can be avoided as much as possible, and thus the waste of resources such as equipment, labor or power can be reduced.

[0107] The embodiments of the present application also provide a wafer monitoring method for non-metal CMP, which can be applied to a CMP device and the like, and the present application is not limited thereto.

[0108] The difference between the above embodiments and the present embodiment is that the CMP device in the present embodiment includes a driving member (for example, a motor or the like) for controlling the rotation of the polishing pad or the polishing head. In the process of chemical mechanical polishing, the friction between the wafer and the polishing pad changes, at which time the driving member automatically adjusts the torque of itself so that the polishing pad or the polishing head controlled by the driving member can maintain a relatively constant rotating speed. Therefore, at least one torque value of the driving member can be measured for judging the slip. The controller is used to execute the wafer monitoring method for non-metal CMP.

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

[0110] Figure 10 The flow chart of the wafer monitoring method for non-metal CMP is an embodiment of the present application. As shown in the figure, the wafer monitoring method for non-metal CMP comprises the following steps: Figure 10

[0111] Step 1001, during the chemical mechanical polishing of the non-metal 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.

[0112] In one specific embodiment, 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 edge of the bottom surface of the polishing head on the polishing pad, and the collected images are all first images. The torque value of the driving member can also be periodically collected. In the present embodiment, the image collection period of the image collector is not limited, 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 period for collecting the torque value of the driving member is also not limited in the present embodiment.

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

[0114] During the chemical mechanical polishing, whether the wafer slips will directly affect the width of the bow wave near the edge of the bottom surface of the polishing head on the polishing pad. Specifically, when the wafer does not slip, the polishing head abuts the wafer on 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 collected first image is stable around a first value. When the wafer slips, the space below the polishing head changes suddenly, and the polishing liquid switches from one steady state to another, so that the width of the bow wave in the collected first image changes, for example, it is stable around a second value. Since the wafer slips out from below the polishing head, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the wafer abutting 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 increases, and the amount of polishing liquid accumulated on the polishing pad near the edge of the bottom surface of the polishing head decreases. 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, i.e., the second value is generally smaller 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, in the chemical mechanical polishing process, the polishing liquid based on flow itself has certain fluctuation, and the polishing head drives the wafer to move reciprocatingly along the radial direction of the polishing pad, and for these reasons, the width of the bow wave will have relatively large fluctuations regularly, whether the wafer is sliding or not. In addition, the width of the bow wave before and after the wafer slides will be stable around different values, therefore, the first value and the second value described above are the approximate values of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0116] In the process of chemical mechanical polishing, whether the wafer slides directly affects the torque value of the driving part. Specifically, when the wafer is not sliding, the polishing head abuts the wafer against the polishing pad, at this time, the friction between the wafer and the polishing pad is large, so that the torque value of the driving part is large; when the wafer slides, the wafer is separated from the polishing head, at this time, the polishing head and the polishing pad are not in contact or in contact with each other but the friction is small, so that the torque value of the driving part is small, therefore, compared with the torque value of the driving part when the wafer is not sliding, the torque value of the driving part when the wafer slides is generally smaller.

[0117] Based on this, in one specific embodiment, after the at least one first image and the at least one torque value are collected, 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 first image collected is small and at least part 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, thereby achieving monitoring of wafer sliding.

[0118] Alternatively, 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 collection area of the image collector. The specific determination method of the width of the bow wave in the image is not limited in the embodiments of the present application.

[0119] In the embodiment of the present application, at least one first image collected by the image collector and at least one torque value of the driving member are obtained during the chemical mechanical polishing of the non-metal layer of the wafer by the CMP device, 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 short-lived change of the laser collected by the optical sensor, the width of the bow wave near the polishing head on the polishing pad and the torque value of the driving member are used to monitor whether the wafer has slipped in the embodiment of the present application. After the wafer slips, the width of the bow wave is almost always stable at a smaller state, and the torque value of the driving member is also almost always smaller, which reduces the possibility of false positives and false negatives 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, the width of the bow wave near the polishing head on the polishing pad and the torque value of the driving member are used for double judgment, which can make the monitoring result of monitoring the wafer slip more accurate.

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

[0122] In one 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 whether the width of the bow wave in the at least one first image meets the second slip condition is determined on the basis that the at least one torque value meets the third slip condition, the order of determining whether it meets the third slip condition and determining whether it meets the second slip condition is not limited in the embodiment of the present application, and both can be performed at the same time, which improves the efficiency of determining whether the wafer has slipped relative to the polishing head.

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

[0124] In the embodiment of the present application, compared with the previous implementation mode in which the order of determining whether the third slide condition is met and determining whether the second slide condition is met is not limited, in the embodiment of the present application, it is determined whether the width of the bow wave in the at least one first image meets the second slide condition on the basis that the at least one torque value meets the third slide condition, and then it is determined that the at least one torque value does not meet the third slide condition, so that it is not necessary to determine whether the width of the bow wave in the at least one first image meets the second slide condition, thereby saving the computing resources.

[0125] In a possible implementation, the wafer monitoring method for non-metal CMP further comprises the following process: determining a target torque value according to the at least one torque value; and if the target torque value is less than a torque threshold, determining that the at least one torque value meets the third slide condition.

[0126] In a specific embodiment, the at least one torque value can be all the torque values collected in the process of performing chemical mechanical polishing on the non-metal layer of the wafer by the CMP device, based on which the last torque value in the at least one torque value can be determined as the target torque value, the average of the last several torque values in the at least one torque value can be determined as the target torque value, and the like; after the target torque value is determined, if the target torque value is less than the torque threshold, it is determined that the at least one torque value meets the third slide condition, otherwise, it is determined that the at least one torque value does not meet the third slide condition. 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 configured to collect the image of the bow wave at a target portion of the polishing pad close to the polishing head, and the target portion is a portion of the polishing head close to the liquid supply arm.

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

[0129] Optionally, the image collector can be further connected with a jet component for cleaning the image collector, so as to reduce the influence of the polishing liquid splashed to the image collector on the definition of the image collected by the image collector.

[0130] Optionally, inert dyes or inert fluorescent dyes can be added to the polishing liquid for cooperation with the collection; if the fluorescent dyes are added to the polishing liquid, the chemical mechanical polishing process should be in a closed and light-proof environment, and an ultraviolet lamp is added to the environment, so that the bow wave in the image collected by the image collector is clearer.

[0131] The way of determining whether the width of the bow wave in the at least one first image meets the second slip sheet condition has been described in the foregoing embodiment of the wafer monitoring method for metal CMP, and will not be described here again.

[0132] In one possible implementation, the wafer monitoring method for non-metal CMP further includes the following specific processing: 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 is ended.

[0133] In one possible implementation, the wafer monitoring method for non-metal CMP further includes the following specific processing: during the chemical mechanical polishing of the non-metal layer of the wafer by the CMP device, it is determined whether the time endpoint of the chemical mechanical polishing has been reached according to the torque value of the driving member; if the time endpoint of the chemical mechanical polishing has been reached, the chemical mechanical polishing is ended.

[0134] The torque monitoring method is suitable for endpoint judgment during the chemical mechanical polishing of the non-metal layer of the wafer, and is especially suitable for endpoint judgment during the chemical mechanical polishing of the outer non-metal layer of the two adjacent non-metal layers of the wafer. Since the materials of the two non-metal layers are different, the friction forces when the two non-metal layers contact the polishing pad during the chemical mechanical polishing are also different, and the torque values of the driving member when the two non-metal layers contact the polishing pad during the chemical mechanical polishing are different. When the outer non-metal layer is polished and removed, the other non-metal layer contacts the polishing pad, and the torque value of the driving member becomes larger, so that the polishing endpoint can be monitored by monitoring the torque.

[0135] Based on this, in one specific embodiment, when the CMP device is mechanically and chemically polishing the non-metal layer of the wafer, it is determined whether to enter the first preset time (the first preset time can be the time when the torque value starts to rise), if yes, a plurality of groups of torque values are continuously collected every preset time (for example, 1s), each group of torque values includes at least one torque value, the torque average of each group of torque values is obtained, and it is determined whether the absolute error between the torque average and the first torque value in the next group of torque values is less than the first preset value (for example, ±0.05%), if yes, the time when the motor torque value is maximum is obtained, and it is determined whether the difference between the torque averages of the two groups of torque values adjacent to the torque average is greater than the second preset value (for example, 0.1%), if yes, it indicates that the non-metal layer to be polished has been almost polished, at this time, the current time can be determined as the time endpoint, and the chemical mechanical polishing is ended. In addition, if the difference between the current time and the time when the motor torque value is maximum is greater than the protection time, the chemical mechanical polishing can also be ended.

[0136] In the embodiments of the present application, the chemical mechanical polishing is automatically ended by monitoring the torque of the driving member, and the possibility of over-polishing the wafer or insufficient polishing of the wafer is reduced.

[0137] In one possible implementation, in the process of chemical mechanical polishing of the non-metal layer of the wafer by the CMP device, the time when the first first image is collected by the image collector is the same as the time when the first torque value of the driving member is obtained.

[0138] Therefore, in the process of chemical mechanical polishing of the non-metal layer of the wafer by the CMP device, the acquisition of the first image and the acquisition of the torque value almost start at the same time, and the situation that 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 can be avoided as much as possible, and the waste of resources such as equipment, labor or power can be reduced.

[0139] The embodiments of the present application also provide a wafer monitoring method for chemical mechanical polishing, which can be applied to a CMP device and the like, and the present application is not limited thereto.

[0140] It should be noted that the width of the bow wave is greatly affected by the rotation speed of the polishing disc, the rotation speed of the polishing head, the liquid supply speed of the liquid supply arm, the ratio of the polishing liquid, the image acquisition position and the like in the chemical mechanical polishing process, and therefore the time value or the bow wave width value and the like in the present application are examples and are not used to limit the protection scope of the present application. Those skilled in the art can change them according to the actual process scene, and all changes are within the protection scope of the present application.

[0141] Figure 1 is a schematic diagram of the CMP device of one embodiment of the present application. As shown in Figure 1As shown in the figure, w is a wafer, the CMP device is used for chemical mechanical polishing of the wafer, specifically chemical mechanical polishing of a metal layer or a non-metal layer of the wafer, and the CMP device comprises a polishing disc 1, a polishing head support 2, a polishing head 3, a liquid supply arm, an image collector 4 (for example, a high-speed camera or the like) and a controller; the polishing disc 1 is provided with a circular pad-shaped polishing pad 11 on one side, the polishing disc 1 is used to drive the polishing pad 11 to rotate around the axis of the polishing pad 11, and the side of the polishing pad 11 away from the polishing disc 1 is a polishing surface; the polishing head support 2 is connected with 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 on the polishing surface, specifically to drive the polishing head 3 to drive the metal layer or the non-metal layer to be polished on the wafer to abut on 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 move reciprocatingly on the polishing surface along the radial direction of the polishing surface, so as to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to supply polishing liquid to the polishing pad 11 in the process of performing chemical mechanical polishing on the wafer; the image collector 4 is connected to the polishing head support 2, the collecting lens of the image collector 4 faces the polishing pad 11 close to the polishing head 3, and the image collector 4 is used to collect the image of a bow wave formed by the polishing liquid on the polishing pad 11 close to the polishing head 3; and the controller is used to execute the wafer monitoring method for chemical mechanical polishing.

[0142] Optionally, the polishing head 3 and the polishing head support 2 can both be provided in a cylindrical shape, and the image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head support 2, in the process of chemical mechanical polishing, since the axis of the polishing head support 2, the axis of the polishing head 3 and the axis of the wafer all coincide, and the reciprocating movement of the wafer is achieved by driving the polishing head support 2 to move reciprocatingly through an external force, therefore the polishing head 3 will rotate relative to the image collector 4 around the axis of the wafer itself, but the relative position between the polishing head 3 and the image collector 4 will not change, so that the image collector 4 can more stably collect the image of the bow wave on the polishing pad 11 close to the polishing head 3, specifically more stably collect the image of the bow wave on the polishing pad 11 close to the bottom edge of the polishing head 3.

[0143] The wafer monitoring method for chemical mechanical polishing is described in detail through multiple embodiments as follows.

[0144] Figure 11 is a flow chart of the wafer monitoring method for chemical mechanical polishing according to an embodiment of the present application. As shown in the figure, the wafer monitoring method for chemical mechanical polishing comprises the following steps: Figure 11

[0145] Step 1101, in the process of chemical mechanical polishing of the wafer by the CMP device, at least one first image collected by the image collector is acquired. ​

[0146] In one embodiment, 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 edge of the bottom surface of the polishing head on the polishing pad, and the collected images are all regarded as the first images. In the embodiment of the present application, the image collection period of the image collector is not limited, 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 the at least one first image meets the second slide condition, it is determined that the wafer has been slid relative to the polishing head.

[0148] During the chemical mechanical polishing, whether the wafer slides directly affects the width of the bow wave near the edge of the bottom surface of the polishing head on the polishing pad. Specifically, when the wafer does not slide, the polishing head abuts the wafer on 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 collected first image is stable around a first value. When the wafer slides, the space below the polishing head changes suddenly, and the polishing liquid switches from one steady state to another, so that the width of the bow wave in the collected first image changes. For example, the width of the bow wave in the collected first image is stable around a second value. After the wafer slides out from below the polishing head, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the wafer 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 increases, and the amount of polishing liquid accumulated near the edge of the bottom surface of the polishing head on the polishing pad decreases. 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 smaller 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, due to the inherent volatility of the flowing polishing liquid and the reciprocating movement of the wafer along the radial direction of the polishing pad driven by the polishing head, the width of the bow wave will fluctuate regularly regardless of whether the wafer slides or not. In addition, the width of the bow wave will be stable around different values when the wafer does not slide and when the wafer slides, respectively. Therefore, the first value and the second value described above are 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 one specific embodiment, after the at least one first image is collected, 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 first image collected is small (for example, less than a certain threshold), it is determined that the width of the bow wave in the at least one first image meets the second slide condition, and it is further determined that the wafer has occurred sliding relative to the polishing head. Otherwise, it is determined that the width of the bow wave in the at least one first image does not meet the second slide condition, and it is further determined that the wafer has not occurred sliding relative to the polishing head. Thus, the wafer sliding is monitored.

[0151] Alternatively, 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 collection area of the image collector. The specific determination method of the width of the bow wave in the image is not limited in the embodiments of the present application.

[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 at least one first image meets the second slide condition, it is determined that the wafer has occurred sliding relative to the polishing head. Thus, compared with monitoring the wafer sliding by the short-term change of the laser collected by the optical sensor, the width of the bow wave near the polishing head on the polishing pad is used to monitor whether the wafer has occurred sliding in the embodiments of the present application. When the wafer has occurred sliding, the width of the bow wave is almost always stable at a small state. Thus, the width of the bow wave in the at least one first image collected at most time when the wafer has occurred sliding meets the second slide condition. The possibility of false positives and false negatives when monitoring the wafer sliding is reduced. Thus, the monitoring result of monitoring the wafer sliding is more accurate.

[0153] In one possible implementation, the image collector is configured to collect an image of the bow wave at a target portion of the polishing pad near the polishing head. The target portion is a portion of the polishing head near the liquid supply arm.

[0154] In one 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. The lens of the image collector faces the target portion of the polishing pad near the polishing head. Thus, the image collector can collect the bow wave near the position of the liquid supply arm. The width of the collected bow wave is larger, and the collected bow wave is more obvious. Thus, the monitoring result of monitoring the wafer sliding is more accurate.

[0155] Alternatively, the image collector can be further connected with a jet component for cleaning the image collector, so as to reduce the influence of the polishing liquid splashed to the image collector on the definition of the image collected by the image collector.

[0156] Optionally, inert dyes or inert fluorescent dyes can be added to the polishing liquid to assist in the collection; if fluorescent dyes are added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-proof environment, and an ultraviolet lamp is added to the environment to make the bow waves in the images collected by the image collector clearer.

[0157] The way of 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 embodiment of the wafer monitoring method for metal CMP, and will not be described here again.

[0158] Corresponding to the foregoing embodiment of the wafer monitoring method for metal CMP, as shown in Figure 1 The CMP device comprises a polishing disc 1, a polishing head 3, a liquid supply arm, an image collector 4, an eddy current sensor, and a controller.

[0159] The polishing disc 1 is provided with a polishing pad 11 on one side thereof;

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

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

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

[0163] 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 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 of the 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 described here again.

[0166] Corresponding to the foregoing embodiment of the wafer monitoring method for non-metal CMP, as shown in Figure 1 The CMP device comprises a polishing disc 1, a polishing head 3, a liquid supply arm, an image collector 4, and a controller.

[0167] The polishing disc 1 is provided with a polishing pad 11 on one side thereof;

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

[0169] The liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing on the wafer.

[0170] The image collector 4 is used to collect the image of the arch wave formed by the polishing liquid on the polishing pad 11 close to the polishing head 3.

[0171] The driving member is used to control the rotation of the polishing pad or the polishing head.

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

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

[0174] It should be noted that the CMP device of the present embodiment is used to implement the corresponding wafer monitoring method for non-metal CMP in the above-mentioned method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described here again.

[0175] Corresponding to the above-mentioned wafer monitoring method embodiments for chemical mechanical polishing, as shown in Figure 1 The CMP device comprises a polishing disc 1, a polishing head 3, a liquid supply arm, an image collector 4 and a controller.

[0176] The polishing disc 1 is provided with a polishing pad 11 on one side.

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

[0178] The liquid supply arm is used to supply polishing liquid to the polishing pad 11 during the chemical mechanical polishing on the wafer.

[0179] The image collector 4 is used to collect the image of the arch wave formed by the polishing liquid on the polishing pad 11 close to the polishing head 3.

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

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

[0182] It should be noted that the CMP device of the present 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 described here.

[0183] The present application also provides a computer-readable storage medium storing instructions for causing a machine to perform a wafer monitoring method for metal CMP, a wafer monitoring method for non-metal CMP, or a 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 a software program code realizing the functions of any one of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device is caused to read out and execute the program code stored in the storage medium.

[0184] In this case, the program code read from the storage medium itself realizes the functions of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present application.

[0185] Embodiments of the storage medium for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, a DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer via a communication network.

[0186] The present application embodiment also provides a computer program product comprising computer instructions instructing a computing device to perform any corresponding operation in the above-mentioned method embodiments.

[0187] It should be noted that the information related to the user (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to sample data for training the model, data for analysis, stored data, displayed data, etc.) involved in the present application embodiment are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of the related data need to comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation portal for the user to choose authorization or refusal.

[0188] It should be noted that according to the needs of implementation, each component / step described in the present application embodiment can be split into more components / steps, or two or more components / steps or part of the operation of the components / steps can be combined into a new component / step to achieve the purpose of the present application embodiment.

[0189] The method according to the embodiments of the present application described above can be implemented in hardware, firmware, or as software stored in a recording medium such as a CD ROM, a RAM, a floppy disk, a hard disk, or a magneto-optical disk, or computer code downloaded from a network and stored in a remote recording medium or a non-transitory machine readable medium and then stored in a local recording medium, so that the method described herein can be processed by such software using a general purpose computer, a special purpose processor, or programmable or special purpose hardware such as an ASIC or an FPGA. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component (for example, a RAM, a ROM, a flash memory, and the like) 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 will convert the general purpose computer into a special purpose computer for executing the method shown herein.

[0190] It should be noted that the information related to the user (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to sample data for training the model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation portal for user to choose authorization or refusal.

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

[0192] The above embodiments are only used to illustrate the embodiments of the present application, and not to limit the embodiments of the present application. Those skilled in the art can 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 should be defined by the claims.

Claims

1. A wafer monitoring method for metal CMP, characterized in that, include: During the chemical mechanical polishing of the metal layer of a wafer by a CMP device, at least one first image is acquired by an image acquisition device, and a wafer signal is acquired by an eddy current sensor when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad. The CMP device includes a polishing head, a polishing pad, and a liquid supply arm. The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used to supply polishing liquid to the polishing surface, and the image acquisition device is used to acquire an image of the bow wave formed by the polishing liquid near the polishing head on the polishing pad. If the signal strength of the wafer signal is less than the strength threshold, or the absolute value of the slope of the wafer signal is greater than the slope threshold, then the wafer signal is determined to meet the first sliding condition. If the wafer signal meets the first sliding condition, then it is determined whether the width of the bow wave in the at least one first image meets the second sliding condition; wherein, the first bow wave width is determined according to the width of the bow wave in the at least one first image, and if the first bow wave width is less than the first width threshold, then it is determined that the width of the bow wave in the at least one first image meets the second sliding condition. If the width of the bow wave in 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 includes: Based on at least one of the comparison results of the first bow wave width, the first change data, the second change data, and the first change data, it is determined whether the width of the bow wave in the at least one first image meets the second slip condition. The first bow wave width is the width obtained based on the width of the bow wave in the at least one first image. The first change data is used to indicate the change in the width of the bow wave in the first image as the time of acquisition of the first image is within the monitoring period. The second change data is used to indicate the change in the width of the bow wave in the second image acquired by the image acquisition device as the time of acquisition of the second image is within the control period when the wafer does not slip relative to the polishing head.

3. The method according to claim 1, characterized in that, The method further includes: During the chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, at least one third image is acquired by the image acquisition device when the wafer does not slip relative to the polishing head; The width of the second bow wave is determined based on the width of the bow wave in the at least one third image; The first width threshold is determined based on the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

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

5. The method according to claim 4, characterized in that, The step of determining whether the width of the bow wave in the plurality of first images meets the second slider condition based on the first change data includes: The monitoring time period is divided into multiple consecutive unit time periods, wherein each unit time period has the same duration. Based on the first change data, the characteristic value corresponding to each unit time period is determined, wherein the characteristic value corresponding to the unit time period is used to indicate the bow width change corresponding to the unit time period; Based on the feature values ​​corresponding to the multiple unit time periods, determine whether the width of the bow wave in the multiple first images meets the second slider condition.

6. The method according to claim 5, characterized in that, The step of determining whether the width of the bow wave in the multiple first images meets the second sliding condition based on the feature values ​​corresponding to the multiple unit time periods includes: Based on the feature values ​​corresponding to the multiple unit time periods, it is determined whether there is a target time period within the monitoring time period, wherein the target time period includes a consecutive number of unit time periods, and the sum of the feature values ​​corresponding to the number of unit time periods exceeds a first threshold. If a target time period exists within the monitoring time period, and the sum of the feature values ​​corresponding to the unit time period before the target time period is less than the second threshold, and the third bow wave width determined based on at least a portion of the first change data after the target time period is less than the second width threshold, then it is determined that the width of the bow wave in the plurality of first images meets the second sliding condition.

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

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

9. The method according to claim 1, characterized in that, During the chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, the time when the image acquisition device acquires the first first image is the same as the time when the eddy current sensor begins to acquire the wafer signal.

10. A CMP device, characterized in that, include: Polishing disc, polishing head, liquid supply arm, image acquisition unit, 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 to drive the wafer to move relative to the polishing pad in order to perform chemical mechanical polishing on the wafer. The liquid supply arm is used to supply polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; The image acquisition device is used to acquire an image of the bow wave formed by the polishing fluid on the polishing pad near the polishing head; The eddy current sensor is used to acquire wafer signals when the eddy current sensor is opposite the wafer in a direction perpendicular to the polishing pad. The controller is configured to perform the wafer monitoring method for metal CMP as described in any one of claims 1-9.

11. A computer storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the wafer monitoring method for metal CMP as described in any one of claims 1-9.

12. A computer program product, characterized in that, Includes computer instructions that instruct a computing device to perform a wafer monitoring method for metal CMP as described in any one of claims 1-9.

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