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

Abstract

The embodiment of the present application provides a wafer monitoring method for metal CMP, a CMP device, and a computer storage medium, the method comprising: in the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, obtaining 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 to the wafer in a direction perpendicular to the polishing pad, wherein the CMP device comprises a polishing head, a polishing pad, and a liquid supply arm, the polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad, the liquid supply arm is used to provide polishing liquid to the polishing surface, and the image collector is used to collect an image of a bow wave formed by the polishing liquid near the polishing head on the polishing pad; according to the width of the bow wave in at least one first image and the wafer signal, determining whether the wafer has slipped relative to the polishing head. This solution can make the monitoring result of wafer slip more accurate.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wafer polishing technology, and in particular to a wafer monitoring method, CMP equipment, and computer storage medium for metal CMP. Background Art

[0002] During the wafer manufacturing process, the metal layer on the wafer surface is planarized through chemical mechanical polishing (CMP).

[0003] The CMP equipment includes a polishing head and a polishing pad. An optical sensor is arranged on the polishing head. When the CMP equipment performs CMP on the wafer, 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 with polishing liquid supplied 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 detaching from the polishing head). For example, when slipping occurs, the wafer slides out from under 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.

[0004] However, when the wafer slips, the light collected by the optical sensor will return to the laser reflected by the polishing pad after the wafer passes through the monitoring light path of the optical sensor. Therefore, when the wafer slips, the light collected by the optical sensor is the laser reflected by the wafer for a relatively short time, which makes it easy for false alarms and missed alarms to occur when monitoring wafer slip. Therefore, the monitoring results of wafer slip are relatively inaccurate. Summary of the invention

[0005] In view of this, embodiments of the present application provide a wafer monitoring method, CMP equipment, and computer storage medium for metal CMP to at least partially solve the above problems.

[0006] According to a first aspect of an embodiment of the present application, a wafer monitoring method for metal CMP is provided, comprising: during a process in which a CMP device performs chemical mechanical polishing on a metal layer of a wafer, acquiring at least one first image acquired by an image collector, and a wafer signal acquired by the eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad, wherein the CMP device comprises a polishing head, a polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a polishing surface of the polishing pad, the liquid supply arm is used to provide polishing liquid to the polishing surface, and the image collector is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; and determining whether the wafer has slipped relative to the polishing head based on the width of the bow wave in the at least one first image and the wafer signal.

[0007] According to a second aspect of an embodiment of the present application, a wafer monitoring method for non-metallic CMP is provided, comprising: during a process in which a CMP device performs chemical mechanical polishing on a non-metallic layer of a wafer, acquiring at least one first image acquired by an image acquisition device and at least one torque value of a driving member, wherein the CMP device comprises 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 provide polishing liquid to the polishing surface, the image acquisition device is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head, and the driving member is used to control the rotation of the polishing pad or the polishing head; based on the width of the bow wave in the at least one first image and the at least one torque value, determining whether the wafer has slipped relative to the polishing head.

[0008] According to a third aspect of an embodiment of the present application, a wafer monitoring method for chemical mechanical polishing is provided, comprising: during a process in which a CMP device performs chemical mechanical polishing on a wafer, acquiring at least one first image acquired by an image collector, wherein the CMP device comprises a polishing head, a polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a polishing surface of the polishing pad, the liquid supply arm is used to provide polishing liquid to the polishing surface, and the image collector is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; if the width of the bow wave in the at least one first image meets a second slip condition, it is determined that the wafer has slipped relative to the polishing head.

[0009] According to the fourth aspect of the embodiment of the present application, a CMP device is provided, comprising: a polishing disk, a polishing head, a liquid supply arm, an image collector, an eddy current sensor and a controller; a polishing pad is provided on one side of the polishing disk; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad, and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is used to capture an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the eddy current sensor is used to capture wafer signals when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad; the controller is used to execute the method of the first aspect above.

[0010] According to the fifth aspect of the embodiment of the present application, a CMP device is provided, comprising: a polishing disk, a polishing head, a liquid supply arm, an image collector, a driving member and a controller; a polishing pad is provided on one side of the polishing disk; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad, and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is used to capture an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the driving member is used to control the rotation of the polishing pad or the polishing head; the controller is used to execute the method of the above second aspect.

[0011] According to the sixth aspect of the embodiment of the present application, a CMP device is provided, comprising: a polishing disk, a polishing head, a liquid supply arm, an image collector and a controller; a polishing pad is provided on one side of the polishing disk; the polishing head is used to drive a wafer to abut against the polishing surface of the polishing pad, and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing liquid to the polishing pad during the chemical mechanical polishing of the wafer; the image collector is used to capture an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; the controller is used to execute the method of the third aspect above.

[0012] According to a seventh aspect of the embodiments of the present application, a computer storage medium is provided, on which a computer program is stored, and the program is executed by a processor to perform the method of the first aspect, the second aspect or the third aspect.

[0013] According to an eighth aspect of an embodiment of the present application, a computer program product is provided, comprising computer instructions, wherein the computer instructions instruct a computing device to execute the method of the first aspect, the second aspect or the third aspect.

[0014] According to the wafer monitoring scheme for metal CMP provided in the embodiment of the present application, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, at least one first image collected by the image collector and the wafer signal collected by the eddy current sensor when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad are obtained, 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. Therefore, compared with monitoring the wafer slip by the relatively short-term change of the laser collected by the optical sensor, in the embodiment of the present application, 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. 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 basically always stable at 0 after it decreases to 0 quickly, which reduces the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring result of monitoring the wafer slip is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0016] Figure 1 is a schematic diagram of a CMP device according to an embodiment of the present application;

[0017] Figure 2 is a schematic diagram of a wafer signal according to an embodiment of the present application;

[0018] Figure 3 is a flow chart of a wafer monitoring method for metal CMP according to an embodiment of the present application;

[0019] Figure 4 is a schematic diagram of a signal strength variation curve of an embodiment of the present application;

[0020] Figure 5 is a flow chart of determining whether the second sliding sheet condition is met according to an embodiment of the present application;

[0021] Figure 6 is a schematic diagram of a first sub-curve graph and a second sub-curve graph of an embodiment of the present application;

[0022] Figure 7 is a flowchart of determining whether the second sliding sheet condition is met according to another embodiment of the present application;

[0023] Figure 8is a flowchart of determining whether the second sliding sheet condition is met according to another embodiment of the present application;

[0024] Fig. 9 is a flowchart of determining whether the second sliding sheet condition is met in another embodiment of the present application;

[0025] Fig.10 is a flow chart of a wafer monitoring method for non-metallic CMP according to an embodiment of the present application;

[0026] Fig.11 It is a flow chart of a wafer monitoring method for chemical mechanical polishing according to an embodiment of the present application.

[0027] Description of reference numerals:

[0028] 1. Polishing disc; 11. Polishing pad; 2. Polishing head bracket; 3. Polishing head; 4. Image collector; 5. Eddy current sensor; w. Wafer. DETAILED DESCRIPTION

[0029] The embodiment of the present application provides a wafer monitoring method for metal CMP. The wafer monitoring method for metal CMP can be applied to CMP equipment, etc., and the embodiment of the present application is not limited to this.

[0030] Figure 1 Schematic diagram of a CMP device according to an embodiment of the present application. Figure 1As shown, w is a wafer, and the CMP equipment is used to perform chemical mechanical polishing on the wafer, specifically, to perform chemical mechanical polishing on the metal layer of the wafer. The CMP equipment includes: a polishing disc 1, a polishing head bracket 2, a polishing head 3, a liquid supply arm, an image collector 4 (such as a high-speed camera, etc.), an eddy current sensor and a controller; a circular pad-shaped polishing pad 11 is provided on one side of the polishing disc 1, and 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 bracket 2 is connected to the polishing head 3, and the polishing head 3 is located between the polishing head bracket 2 and the polishing pad 11. The polishing head bracket 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 relative to the polishing pad 11 around the axis of the wafer, 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. light; the liquid supply arm is used to provide 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 bracket 2, and the acquisition lens of the image collector 4 is facing the polishing pad 11 near 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 near the polishing head 3; the eddy current sensor is arranged in the polishing plate 1, for example, a mounting groove for installing the eddy current sensor can be opened on the side of the polishing plate 1 near the polishing pad 11, during the chemical mechanical polishing process, the eddy current sensor rotates with the polishing plate 1, so that the eddy current sensor and the wafer are opposite to each other in the direction perpendicular to the polishing pad for part of the time during the chemical mechanical polishing process, and the eddy current sensor and the wafer are not opposite to each other in the direction perpendicular to the polishing pad at other times, and the eddy current sensor is used to collect wafer signals when the eddy current sensor and the wafer are opposite to each other in the direction perpendicular to the polishing pad; the controller is used to execute the wafer monitoring method for metal CMP.

[0031] Optionally, the shapes of the polishing head 3 and the polishing head bracket 2 can be set to be cylindrical, and the image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head bracket 2. During the chemical mechanical polishing process, since the axis of the polishing head bracket 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 bracket 2 to move back and forth by external force, the polishing head 3 will rotate around the axis of the wafer itself relative to the image collector 4, but the relative position between the polishing head 3 and the image collector 4 will not change, so that the image collector 4 can more stably capture the image of the bow wave on the polishing pad 11 near the polishing head 3, specifically, it can more stably capture the image of the bow wave on the polishing pad 11 near the bottom edge of the polishing head 3.

[0032] It should be noted that if Figure 2As shown, when the eddy current sensor 5 is facing a metal object, an induced magnetic field is generated on the metal object. The range of the induced magnetic field is as follows: Figure 2 As shown by the dotted circle on the surface of the wafer w, the eddy current sensor can collect signals, and then the eddy current sensor 5 can collect wafer signals when the eddy current sensor 5 is opposite to the wafer w in a direction perpendicular to the polishing pad.

[0033] The wafer monitoring method for metal CMP is described in detail below through multiple embodiments.

[0034] Figure 3 FIG. 1 is a flow chart of a wafer monitoring method for metal CMP according to an embodiment of the present application. Figure 3 As shown, the wafer monitoring method for metal CMP includes the following steps:

[0035] Step 301, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, obtaining at least one first image captured by the image collector, and a wafer signal captured by the eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad.

[0036] In a specific embodiment, during the process of chemical mechanical polishing of a wafer by a CMP device, an image collector can be controlled to periodically capture images of the bow wave near the bottom edge of the polishing head on the polishing pad, and all the captured images are used as the first image. When the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad, the wafer signal captured by the eddy current sensor can also be obtained. The embodiment of the present application does not limit the image capture period of the image collector. For example, the image collector can be controlled to capture the first image at a shutter speed of 0.02s and an image capture frequency of 5Hz.

[0037] Step 302: Determine whether the wafer has slipped relative to the polishing head based on the width of the bow wave in at least one first image and the wafer signal.

[0038] During the chemical mechanical polishing process, whether the wafer slips will directly affect the width of the bow wave on the polishing pad near the bottom edge of the polishing head. Specifically, when the wafer does not slip, the polishing head abuts the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near the first value. When the wafer slips, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another, so that the width of the bow wave in the first image collected at this time will change, for example, it will be stable near the second value. Since the wafer slides out from under the polishing head, Afterwards, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the pressure of the wafer between the polishing head and the polishing pad is reduced, so that the flow rate of the polishing liquid between the polishing head and the polishing pad becomes larger, and the amount of polishing liquid accumulated on the polishing pad near the edge of the bottom surface of the polishing head becomes less. Therefore, compared with the first image collected when the wafer is not slipped, the width of the bow wave in the first image collected when the wafer is slipped is generally smaller, that is, the second value is generally smaller than the first value, for example, the first value is 8mm and the second value is 5mm, or the first value is 12mm and the second value is 8mm, etc.

[0039] It should be noted that during the chemical mechanical polishing process, due to the certain volatility of the flowing polishing liquid itself and the fact that the polishing head will drive the wafer to move back and forth along the radial direction of the polishing pad, the width of the bow wave will fluctuate more regularly regardless of whether the wafer is sliding or not. In addition, the width of the bow wave will be stable near different values ​​when the wafer is not sliding and when the wafer is sliding. Therefore, the first and second values ​​mentioned above are both approximate values ​​of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0040] During the chemical mechanical polishing process, whether the wafer slips will directly affect the wafer signal. Specifically, when the wafer is not slipping, as the chemical mechanical polishing proceeds, the polished metal layer will gradually become thinner until the thickness of the metal layer meets the requirement, so that the signal strength of the wafer signal will gradually decrease to a value greater than 0; when the wafer is slipping, the wafer is separated from the polishing head, so that the eddy current sensor and the wafer are almost not relative to each other in the direction perpendicular to the polishing pad or are relative for a very short time, and then the eddy current sensor cannot detect the metal layer or detects the metal layer for a very short time, so the signal strength of the wafer signal will quickly decrease to 0. Therefore, compared with the wafer signal when the wafer is not slipping, the signal strength of the wafer signal when the wafer is sliding will decrease to a smaller value more quickly.

[0041] Based on this, in a specific embodiment, after acquiring the above-mentioned at least one first image and wafer, the width of the bow wave in each first image can be determined. When the width of the bow wave in at least one acquired first image is small and the signal strength of the wafer signal decreases to a smaller value relatively 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 realizing the monitoring of wafer slip.

[0042] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or can be calculated by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head within the image acquisition area of ​​the image collector. The specific method for determining the width of the bow wave in the image is not limited in the embodiments of the present application.

[0043] In an embodiment of the present application, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, at least one first image acquired by the image acquisition device and a wafer signal acquired by the eddy current sensor when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad are acquired, 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. Therefore, compared with monitoring the wafer slip by the relatively short-term change of the laser acquired by the optical sensor, in the embodiment 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. 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 basically always stable at 0 after it decreases to 0 quickly, which reduces the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring result of monitoring the wafer slip is more accurate.

[0044] Furthermore, when determining whether the wafer has slipped relative to the polishing head, a dual judgment is made through the width of the bow wave on the polishing pad near the polishing head and the wafer signal, which can make the monitoring result of wafer slip more accurate.

[0045] The above step 302 can be implemented in at least the following two ways.

[0046] In a possible implementation, 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.

[0047] In the embodiment of the present application, compared with the next implementation in which, on the basis that the wafer signal meets the first sliding condition, it is determined whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition, the embodiment of the present application does not limit the order of judging whether the first sliding condition is met and judging whether the second sliding condition is met, and the two can also be performed at the same time, thereby improving the efficiency of determining whether the wafer has slipped relative to the polishing head.

[0048] In another possible implementation, the above step 302 includes the following specific processing: if the wafer signal meets the first sliding condition, then determine whether the width of the bow wave in the above at least one first image meets the second sliding condition; if the width of the bow wave in the above at least one first image meets the second sliding condition, then determine that the wafer has slipped relative to the polishing head. Specifically, it can be determined whether the wafer signal meets the first sliding condition first; if the wafer signal meets the first sliding condition, then determine whether the width of the bow wave in the above at least one first image meets the second sliding condition, if so, then determine that the wafer has slipped relative to the polishing head, otherwise, determine that the wafer has not slipped relative to the polishing head; if the wafer signal does not meet the first sliding condition, then determine that the wafer has not slipped relative to the polishing head.

[0049] In the embodiment of the present application, compared with the previous implementation method in which the order of determining whether the first sliding condition is met and determining whether the second sliding condition is met is not limited, in the embodiment of the present application, on the basis that the wafer signal meets the first sliding condition, it is determined whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition. Further, when the wafer signal does not meet the first sliding condition, there is no need to determine whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition, thereby saving computing resources.

[0050] In one possible implementation, the wafer monitoring method for metal CMP also includes the following processing: if the signal strength of the wafer signal is less than the strength threshold, or the absolute value of the signal strength slope of the wafer signal is greater than the slope threshold, it is determined that the wafer signal meets the first sliding condition; otherwise, it is determined that the wafer signal does not meet the first sliding condition.

[0051] Among them, the intensity threshold and the slope threshold can be set according to actual needs, and the embodiment of the present application does not limit this. The intensity threshold is greater than or equal to 0, and the intensity threshold is less than the target signal strength. The target signal strength is the signal strength of the wafer signal when the pre-calibrated metal layer reaches the target thickness, and the target thickness is the thickness of the metal layer when the pre-set chemical mechanical polishing is completed normally.

[0052] In a specific example, Figure 4 As shown, Figure 4 The conventional curve in the figure is the signal strength variation curve of the wafer signal when no wafer slip occurs. Figure 4 The abnormal curve in is the signal strength change curve of the wafer signal before and after the slip occurs. It can be seen that the wafer slips around the turning point of the abnormal curve. At any position after the turning point of the abnormal curve, the signal strength of the wafer signal can be less than the strength threshold, or the absolute value of the signal strength slope of the wafer signal is greater than the slope threshold. Therefore, it can be determined that the wafer signal corresponding to the abnormal curve meets the first slip condition. At any position in the conventional curve, the signal strength of the wafer signal is not less than the strength threshold, nor is the absolute value of the signal strength slope of the wafer signal greater than the slope threshold. Therefore, it can be determined that the wafer signal corresponding to the conventional curve does not meet the first slip condition.

[0053] In a possible implementation, the image collector is used to collect an image of the bow wave at a target portion of the polishing pad close to the polishing head, where the target portion is a portion of the polishing head close to the liquid supply arm.

[0054] 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, with the lens of the image collector facing the target portion of the polishing pad close to the polishing head. Thus, the image collector can collect the bow wave as close to the position of the liquid supply arm as possible, and the width of the collected bow wave is larger, and the collected bow wave is more obvious, which can make the monitoring results of the wafer slide more accurate.

[0055] Optionally, the image collector may be connected to a jetting assembly for cleaning the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0056] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for collection; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-proof environment, and an ultraviolet lamp should be added to the environment to make the bow wave in the image collected by the image collector clearer.

[0057] The method for determining whether the width of the bow wave in the at least one first image meets the second sliding condition can be as follows: determine whether the width of the bow wave in the at least one first image meets the second sliding condition based on at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data, wherein the first bow wave width is a width obtained based on the width of the bow wave in the at least one first image, the first change data is used to indicate how the width of the bow wave in the first image changes with the time when the first image is collected during the monitoring time period, and the second change data is used to indicate how the width of the bow wave in the second image captured by the image collector changes with the time when the second image is collected during the control time period when the wafer does not slip relative to the polishing head.

[0058] 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 sliding condition. Figure 5 FIG. 1 is a flow chart of determining whether the second sliding sheet condition is met according to an embodiment of the present application. Figure 5 As shown, 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 may include the following steps:

[0059] Step 501: Determine a first bow wave width according to a width of a bow wave in at least one first image.

[0060] Step 502: If the first bow wave width is less than a first width threshold, determine that the width of the bow wave in the at least one first image meets a second slide condition.

[0061] In a specific embodiment, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, a first curve graph can be drawn according to the width of the bow wave in the collected first image, and the first curve graph is synchronously updated as more first images are collected, the vertical axis of the first curve graph represents the width of the bow wave, and the horizontal axis of the first curve graph represents the duration of collecting the first image, based on which, a first sub-curve graph corresponding to the monitoring time period is determined in the first curve graph, and a portion of the width represented by the first sub-curve graph is determined to be relatively stable, and then the first bow wave width is determined according to the portion; after determining the first bow wave width, if the first bow wave width is less than the first width threshold, it is determined that the width of the bow wave in the at least one first image meets the second 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 at about 5mm-10mm, for example, the first width threshold can be set to 5mm or 8mm.

[0062] For example, in Figure 6 The dashed curve (i.e. Figure 6a) in the figure is the first sub-curve graph corresponding to the monitoring time period (0s to 20s). The image acquired by the image collector during the monitoring time period is the at least one first image. By observing the first sub-curve graph, it can be seen that 0s to 1s, 2s to 6s, 8s to 12s, 13s to 17s and 19 to 20s in the detection time period are all parts with relatively stable widths represented in the first sub-curve graph. It can be clearly seen from the figure that the widths represented by these parts are all around 5mm. Therefore, it can be determined that the width of the first bow wave is 5mm. Based on the fact that the width of the first bow wave is less than the first width threshold (the first width threshold is set to 8mm), it is determined that the width of the bow wave in the at least one first image meets the second sliding sheet condition.

[0063] In the embodiment of the present application, when the first bow wave width determined according to the width of the bow wave in the at least one first image is small enough, it can be determined that the width of the bow wave in the at least one first image meets the second sliding condition, which can make the judgment logic simpler and save computing resources.

[0064] Optionally, the wafer monitoring method for metal CMP also includes the following processing: during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, obtaining at least one third image captured by the image collector when the wafer does not slip relative to the polishing head; determining the second bow wave width based on the width of the bow wave in the above at least one third image; determining a first width threshold based on the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

[0065] In a specific embodiment, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, when the wafer does not slip relative to the polishing head, a second curve graph can be drawn according to the width of the bow wave in the collected third image, and the second curve graph can be synchronously updated as more third images are collected. Based on this, the vertical axis of the second curve graph represents the width of the bow wave, the horizontal axis of the second curve graph represents the duration of collecting the third image, a second sub-curve graph corresponding to the reference time period is determined in the second curve graph, and a portion of the second sub-curve graph in which the width is relatively stable is determined, and then the second bow wave width is determined based on the portion; after the second bow wave width is determined, a value less than or equal to the second bow wave width can be used as the first width threshold.

[0066] For example, in Figure 6 The solid curve (i.e. Figure 6b) in the figure is the second sub-curve graph. The image acquired by the image collector in the control time period is the at least one third image. By observing the second sub-curve graph, it can be known that 0s to 1s, 3s to 6s, 8s to 12s, 14s to 17s and 19 to 20s in the detection time period are all parts with relatively stable widths represented in the second sub-curve graph. It can be clearly seen from the figure that the widths represented by these parts are all around 8mm. Therefore, it can be determined that the second bow wave width is 8mm. Further, according to the first width threshold being less than or equal to the second bow wave width, it can be determined that the first width threshold is 8mm.

[0067] In the embodiment of the present application, the first width threshold is less than or equal to the second bow wave width, so that the first bow wave width that is less than the first width threshold can also be less than the second bow wave width. Since the width of the bow wave is generally stable at less than the second bow wave width during wafer sliding, determining that the at least one first image meets the second sliding condition when the first bow wave width is less than the second bow wave width can make the result of determining whether the second sliding condition is met more accurate.

[0068] Optionally, the first width threshold is positively correlated with the second bow wave width. For example, when the second bow wave width is 8 mm, the first width threshold may be 5 mm. When the second bow wave width is 12 mm, the first width threshold may be 8 mm.

[0069] Figure 7 FIG. 1 is a flowchart of another embodiment of the present invention for determining whether the second sliding sheet condition is met. Figure 7 As shown, based on the fact that the at least one first image is a plurality of first images acquired by the image collector within the monitoring time period, the determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data may include the following steps:

[0070] Step 701: Determine first change data according to a plurality of first images.

[0071] Step 702: Determine whether the width of the bow waves in the plurality of first images meets the second sliding condition according to the first change data.

[0072] Among them, the first change data can be a curve graph, a mapping function or a mapping table, etc., which is not limited in the embodiment of the present application.

[0073] In a specific embodiment, the first variation data may be a curve diagram showing the variation of the width of the bow wave in the first image with the time when the first image is acquired during the monitoring period, for example: Figure 6The dashed curve in FIG. 1 can determine the overall change in the width of the bow wave in the first image collected by the image collector during the monitoring period according to the first change data, and based on this, it can be determined whether the width of the bow wave in multiple first images meets the second sliding condition.

[0074] In the embodiment of the present application, when determining whether the width of the bow waves in the plurality of first images meets the second slide condition based on the first change data, the change in the width of the bow waves during the monitoring time period is taken into account, so that the result of determining whether the second slide condition is met is more accurate.

[0075] Optionally, the above step 702 includes the following specific processing: dividing the monitoring time period into a plurality of continuous unit time periods, wherein the duration of each unit time period is the same, and the duration of the unit time period can be set according to actual needs, for example, 1s, 0.5s or 0.06s, etc., which is not limited in the embodiment of the present application; determining a 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 amount of change in the bow wave width corresponding to the unit time period, that is, the greater the amount of change in the bow wave width of any unit time period in the first change data, the greater the characteristic value corresponding to the unit time period, and the greater the amount of change in the bow wave width 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 waves in the plurality of first images meets the second slide condition according to the characteristic values ​​corresponding to the plurality of unit time periods.

[0076] In one example, the first change data is a curve graph showing how the width of the bow wave in the first image changes with the time when the first image is collected during the monitoring time period. Based on this, after the unit time is divided into a plurality of continuous unit time periods, for each unit time period, a plurality of sampling points can be taken from a relatively dispersed portion of the first change data corresponding to the unit time period, and the variance of the width represented by the plurality of sampling points is determined as a characteristic value corresponding to the unit time period. Then, based on the characteristic value corresponding to each unit time period, it is determined whether the width of the bow waves in the plurality of first images meets the second slide condition.

[0077] In another example, the first change data is a curve graph showing how the width of the bow wave in the first image changes with the time when the first image is collected during the monitoring time period. Based on this, after the unit time is divided 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 portion of the first change data corresponding to the unit time period can be determined as a characteristic value corresponding to the unit time period, and then based on the characteristic value corresponding to each unit time period, it is determined whether the width of the bow waves in the plurality of first images meets the second slide condition.

[0078] In the embodiment of the present application, when determining whether the width of the bow waves in the plurality of first images meets the second slide condition based on the first change data, the change in the width of the bow waves in each unit time period is taken into account, that is, the overall change in the width of the bow waves in the monitoring time period is taken into account, so that the result of determining whether the second slide condition is met is more accurate.

[0079] Optionally, the above-mentioned determining whether the width of the bow waves in the multiple first images meets the second sliding condition according to the characteristic values ​​corresponding to the multiple unit time periods includes the following specific processing: determining whether there is a target time period in the monitoring time period according to the characteristic values ​​corresponding to the multiple unit time periods, wherein the target time period includes a continuous target number of unit time periods, and the sum of the characteristic values ​​corresponding to the target number of unit time periods exceeds a first threshold; if 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 a second threshold, and the third bow wave width determined according to at least part of the first change data after the target time period is less than the second width threshold, then it is determined that the width of the bow waves in the multiple first images meets the second sliding condition.

[0080] Among them, the target number, the first threshold and the second threshold can be set according to actual needs. The first threshold can be positively correlated with the target number, and the second threshold is positively correlated with the number of unit time periods before the target time period. The embodiment of the present application does not limit the specific values ​​of the target number, the first threshold and the second threshold.

[0081] In a specific embodiment, when determining whether the width of the bow waves 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 within the monitoring time period. If so, it indicates that there is a first portion in the first change data indicating a drastic change in width. Then, the second threshold can be determined according to the number of unit time periods before the target time period, and it can be determined whether the sum of the characteristic values ​​corresponding to the unit time periods before the target time period is less than the second threshold. If so, it indicates that there is a second portion in the first change data indicating a relatively stable width before the first portion. The third bow wave width can also be determined according to the portion in the first change data indicating a relatively stable width after the target time period (for example, for a portion in the first change data indicating a relatively stable width after the target time period, if the width indicated by the portion is about 5 mm, then the third bow wave width is about 5 mm). The method further comprises the following steps: determining whether the third bow wave width is smaller than a second width threshold (the second width threshold may be set according to actual conditions, for example, the second width threshold may be equal to the first width threshold, which is not limited in comparison with the embodiment of the present application). If so, it indicates that there is a third portion of the first change data indicating a stable and smaller width after the first portion. Therefore, if there is a target time period within the monitoring time period, and the sum of the characteristic values ​​corresponding to the unit time periods before the target time period is smaller than the second threshold, and the third bow wave width determined according to at least part of the first change data after the target time period is smaller than the second width threshold, it indicates that the bow wave width indicated by the first change data is first stable, then changes drastically, and then stabilizes in a smaller state. Then, it can be determined that the width of the bow waves in the plurality of first images meets the second slide condition. Otherwise, it is determined that the width of the bow waves in the plurality of first images does not meet the second slide condition.

[0082] In the embodiment of the present application, when there is a target time period within the monitoring time period, and the sum of the characteristic values ​​corresponding to the unit time periods before the target time period is less than the second threshold 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 is determined that the width of the bow waves in the multiple first images meets the second sliding condition. That is, when the first change data satisfies the indication that the bow wave width is first stable and then changes drastically and then stabilizes near a smaller value, it is determined that the width of the bow waves in the multiple first images meets the second sliding condition. Compared with only considering the change of the bow wave width after the sliding, the embodiment of the present application takes into account the change of the bow wave width before and after the sliding, which can make the result of determining whether the second sliding condition is met more accurate.

[0083] Figure 8 FIG. 1 is a flowchart of determining whether the second sliding sheet condition is met in another embodiment of the present application. Figure 8As shown, based on the fact that the at least one first image is a plurality of first images acquired by the image collector within the monitoring time period, the determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data may include the following steps:

[0084] Step 801: During the process of chemical mechanical polishing of a metal layer of a wafer by a CMP device, a plurality of second images captured by an image collector within a control time period when the wafer does not slip relative to a polishing head are acquired.

[0085] Step 802: Determine second change data according to a plurality of second images.

[0086] Step 803: Determine first change data according to the multiple first images.

[0087] Step 804 , comparing the second change data with the first change data, and determining whether the width of the bow waves in the plurality of first images meets the second sliding condition.

[0088] In a specific example, both the first change data and the second change data can be curve graphs, based on which it can be determined whether the curve similarity between the second change data and the first change data exceeds a similarity threshold. If so, it means that the second change data and the first change data have a large difference, that is, 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 widths of the bow waves in the multiple first images meet the second slide condition. Otherwise, it means that the second change data and the first change data have a small difference, that is, 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 widths of the bow waves in the multiple first images do not meet the second slide condition. The similarity threshold can be set according to actual needs, such as 80%-90%, etc., and the embodiment of the present application is not limited to this.

[0089] In the embodiment of the present application, whether the width of the bow waves in the multiple first images meets the second slide condition is determined by comparing the second change data with the first change data. Compared with directly performing logical judgment on the first change data to determine whether the width of the bow waves in the multiple first images meets the second slide 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. Therefore, while making the result of determining whether the second slide condition is met more accurate, it can also achieve a relatively simple determination of whether the second slide condition is met.

[0090] Fig. 9 FIG. 1 is a flowchart of determining whether the second sliding sheet condition is met in another embodiment of the present application. Fig. 9As shown, based on the at least one first image being a plurality of first images acquired by the image collector within 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 sliding condition based on at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data may include the following steps:

[0091] Step 901: Determine a change curve in a coordinate system according to a plurality of first images.

[0092] Step 902: Convert the change curve to the time domain and perform Fourier transform to obtain a transformation result.

[0093] Step 903: Obtain multiple superimposed waveforms from the transformation results.

[0094] Step 904: If the peak value of the waveform with the largest peak value among the multiple waveforms is smaller than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is smaller than the second peak value, it is determined that the width of the bow wave in the multiple first images meets the second slide condition, wherein the first peak value is larger than the second peak value.

[0095] Among them, the specific values ​​of the first peak value and the second peak value can be set according to actual needs, and the embodiment of the present application does not limit this. For example, the first peak value is equal to 10 mm and the second peak value is equal to 5 mm.

[0096] In a specific embodiment, the widths of the bow waves in the multiple first images are fitted to obtain a variation curve in a coordinate system, the vertical axis of the coordinate system can indicate the width of the bow wave in the first image, and the horizontal axis of the coordinate system can indicate the time when the image collector acquires the first image. After obtaining the variation curve, the variation curve is converted to the time domain and then Fourier transformed to obtain a transformation result, and then multiple superimposed waveforms are extracted from the transformation result. If the peak value of the waveform with the largest peak value among the multiple waveforms is less than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is less than the second peak value, it is determined that the width of the bow waves in the multiple first images meets the second slide condition; otherwise, it is determined that the width of the bow waves in the multiple first images does not meet the second slide condition.

[0097] In the embodiment of the present application, by transforming the change curve determined according to the width of the bow wave in the multiple first images, a transformation result can be obtained, and then according to the transformation result, it can be determined whether the width of the bow wave in the multiple first images meets the second sliding condition, without obtaining more curves, which is convenient for operation.

[0098] In a possible implementation, the wafer monitoring method for metal CMP further includes the following specific processing:

[0099] If it is determined that the wafer has slipped relative to the polishing head, the polishing abnormality can be recorded and the chemical mechanical polishing can be terminated.

[0100] In a possible implementation, the wafer monitoring method for metal CMP further includes the following specific processing:

[0101] During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, it is determined whether the time end of the chemical mechanical polishing has been reached based on the wafer signal collected by the eddy current sensor when the eddy current sensor is opposite to the wafer in the direction perpendicular to the polishing pad; if the time end of the chemical mechanical polishing has been reached, the chemical mechanical polishing is terminated.

[0102] In a specific embodiment, during the process of CMP equipment performing chemical mechanical polishing on the metal layer of the wafer, it can be determined whether the signal strength of the wafer signal is equal to or less than the target signal strength. If so, it is determined that the current time has reached the end time of the chemical mechanical polishing.

[0103] In the embodiment of the present application, chemical mechanical polishing is automatically terminated through a wafer signal, thereby reducing the possibility of over-polishing the wafer or insufficiently polishing the wafer.

[0104] In a possible implementation, during the process of the CMP device performing chemical mechanical polishing on the metal layer of the wafer, the time when the image collector collects the first image is the same as the time when the eddy current sensor starts to collect wafer signals.

[0105] Therefore, during the process of chemical mechanical polishing of the metal layer of the wafer by the CMP equipment, the acquisition of the first image and the acquisition of the wafer signal start almost at the same time, which can avoid the situation where the acquisition of the first image starts too early than the acquisition of the wafer signal, or the acquisition of the wafer signal starts too early than the acquisition of the first image, thereby reducing the waste of resources such as equipment, manpower or electricity.

[0106] The embodiment of the present application also provides a wafer monitoring method for non-metallic CMP. The wafer monitoring method for non-metallic CMP can be applied to CMP equipment, etc., and the embodiment of the present application is not limited to this.

[0107] The difference from the above-mentioned embodiment is that the CMP equipment in this embodiment includes a driving member (such as a motor, etc.) for controlling the rotation of the polishing pad or the polishing head. During the chemical mechanical polishing process, the friction between the wafer and the polishing pad will change. At this time, the driving member will automatically adjust its own torque so that the polishing pad or the polishing head controlled by it can maintain a relatively constant rotation speed. Therefore, at least one torque value of the driving member can be measured for judging the slide; the controller is used to execute the wafer monitoring method for non-metallic CMP.

[0108] The wafer monitoring method for non-metallic CMP is described in detail below through multiple embodiments.

[0109] Fig.10 FIG. 1 is a flow chart of a wafer monitoring method for non-metallic CMP according to an embodiment of the present application. Fig.10 As shown, the wafer monitoring method for non-metallic CMP includes the following steps:

[0110] Step 1001: During the process of chemical mechanical polishing of a non-metallic layer of a wafer by a CMP device, at least one first image captured by an image collector and at least one torque value of a driving component are acquired.

[0111] In a specific embodiment, during the process of chemical mechanical polishing of a wafer by a CMP device, an image collector can be controlled to periodically capture images of a bow wave near the bottom edge of a polishing head on a polishing pad, and all captured images are used as first images. The torque value of a driving member can also be periodically captured. The present application embodiment does not limit the image capture cycle of the image collector. For example, the image collector can be controlled to capture the first image at a shutter speed of 0.02s and an image capture frequency of 5Hz. The present application embodiment does not limit the cycle of capturing the torque value of the driving member.

[0112] Step 1002: Determine whether the wafer has slipped relative to the polishing head based on a width of a bow wave in at least one first image and at least one torque value.

[0113] During the chemical mechanical polishing process, whether the wafer slips will directly affect the width of the bow wave on the polishing pad near the bottom edge of the polishing head. Specifically, when the wafer does not slip, the polishing head abuts the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near the first value. When the wafer slips, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another, so that the width of the bow wave in the first image collected at this time will change, for example, it will be stable near the second value. Since the wafer slides out from under the polishing head, Afterwards, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the pressure of the wafer between the polishing head and the polishing pad is reduced, so that the flow rate of the polishing liquid between the polishing head and the polishing pad becomes larger, and the amount of polishing liquid accumulated on the polishing pad near the edge of the bottom surface of the polishing head becomes less. Therefore, compared with the first image collected when the wafer is not slipped, the width of the bow wave in the first image collected when the wafer is slipped is generally smaller, that is, the second value is generally smaller than the first value, for example, the first value is 8mm and the second value is 5mm, or the first value is 12mm and the second value is 8mm, etc.

[0114] It should be noted that during the chemical mechanical polishing process, due to the certain volatility of the flowing polishing liquid itself and the fact that the polishing head will drive the wafer to move back and forth along the radial direction of the polishing pad, the width of the bow wave will fluctuate more regularly regardless of whether the wafer is sliding or not. In addition, the width of the bow wave will stabilize near different values ​​before and after the wafer slides. Therefore, the first and second values ​​mentioned above are both approximate values ​​of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0115] During the chemical mechanical polishing process, whether the wafer slips will directly affect the torque value of the driving component. Specifically, when the wafer is not slipping, 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 component is large; when the wafer is sliding, the wafer is separated from the polishing head. At this time, the polishing head and the polishing pad are not in contact or are in contact with each other but the friction is small, so that the torque value of the driving component is small. Therefore, compared with the torque value of the driving component when the wafer is not slipping, the torque value of the driving component when the wafer is sliding is generally smaller.

[0116] Based on this, in a specific embodiment, after acquiring the at least one first image and the at least one torque value, the width of the bow wave in each first image can be determined. When the width of the bow wave in the at least one first image acquired is small and at least some of the at least one torque value are small, it can be determined whether the wafer has slipped relative to the polishing head. Otherwise, it is determined that the wafer has not slipped relative to the polishing head, thereby realizing the monitoring of wafer slip.

[0117] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or can be calculated by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head within the image acquisition area of ​​the image collector. The specific method for determining the width of the bow wave in the image is not limited in the embodiment of the present application.

[0118] In an embodiment of the present application, during the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device, at least one first image captured by the image collector and at least one torque value of the driving member are acquired, and then 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. Therefore, compared with monitoring the wafer slip by the relatively short-term change of the laser captured by the optical sensor, in the embodiment of the present application, 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. After the wafer slips, the width of the bow wave is almost always stable at a small state, and the torque value of the driving member is almost always small, which reduces the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring result of the wafer slip is more accurate.

[0119] Furthermore, when determining whether the wafer has slipped relative to the polishing head, a dual judgment is made through the width of the bow wave on the polishing pad close to the polishing head and the torque value of the driving member, which can make the monitoring result of wafer slip more accurate.

[0120] The above step 1002 can be implemented in at least the following two ways.

[0121] In a possible implementation, the above step 1002 includes the following specific processing: if the above at least one torque value meets the third sliding condition, and the width of the bow wave in the above at least one first image meets the second sliding 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 in which the width of the bow wave in the above at least one first image meets the second sliding condition on the basis that the above at least one torque value meets the third sliding condition, the order of determining whether the third sliding condition is met and determining whether the second sliding condition is met is not limited in the embodiment of the present application, and the two can also be performed simultaneously, thereby improving the efficiency of determining whether the wafer has slipped relative to the polishing head.

[0122] In another possible implementation, the step 1002 includes the following specific processing: if the at least one torque value meets the third sliding condition, then determining whether the width of the bow wave in the at least one first image meets the second sliding condition; if the width of the bow wave in the at least one first image meets the second sliding condition, then determining that the wafer has slipped relative to the polishing head. Specifically, it may be determined first whether the at least one torque value meets the third sliding condition; if the at least one torque value meets the third sliding condition, then determining whether the width of the bow wave in the at least one first image meets the second sliding condition; if so, then determining that the wafer has slipped relative to the polishing head; otherwise, determining that the wafer has not slipped relative to the polishing head; if the at least one torque value does not meet the third sliding condition, then determining that the wafer has not slipped relative to the polishing head.

[0123] In the embodiment of the present application, compared with the previous implementation method in which the order of determining whether the third sliding condition is met and determining whether the second sliding condition is met is not limited, in the embodiment of the present application, on the basis that the above-mentioned at least one torque value meets the third sliding condition, it is determined whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition, and then when the above-mentioned at least one torque value does not meet the third sliding condition, there is no need to determine whether the width of the bow wave in the above-mentioned at least one first image meets the second sliding condition, thereby saving computing resources.

[0124] In a possible implementation, the wafer monitoring method for non-metallic CMP further includes the following processing: determining a target torque value based on at least one torque value; if the target torque value is less than a torque threshold, determining that the at least one torque value meets a third sliding condition.

[0125] In a specific embodiment, the at least one torque value can be all the torque values ​​collected during the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device. Based on this, the last torque value of the at least one torque value can be determined as the target torque value, and the average of the last few torque values ​​of the at least one torque value can be determined as the target torque value; after determining the target torque value, if the target torque value is less than the torque threshold, it is determined that the at least one torque value meets the third sliding condition, otherwise, it is determined that the at least one torque value does not meet the third sliding condition. Among them, the torque threshold can be set according to actual needs, and the embodiment of the present application does not limit this.

[0126] In a possible implementation, the image collector is used to collect an image of the bow wave at a target portion of the polishing pad close to the polishing head, where the target portion is a portion of the polishing head close to the liquid supply arm.

[0127] 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, with the lens of the image collector facing the target portion of the polishing pad close to the polishing head. Thus, the image collector can collect the bow wave as close to the position of the liquid supply arm as possible, and the width of the collected bow wave is larger, and the collected bow wave is more obvious, which can make the monitoring results of the wafer slide more accurate.

[0128] Optionally, the image collector may be connected to a jetting assembly for cleaning the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0129] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for collection; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-proof environment, and an ultraviolet lamp should be added to the environment to make the bow wave in the image collected by the image collector clearer.

[0130] The method of determining whether the width of the bow wave in the at least one first image meets the second slider condition has been described in the above-mentioned embodiment of the wafer monitoring method for metal CMP, and will not be repeated here in the embodiment of the present application.

[0131] In a possible implementation, the wafer monitoring method for non-metallic CMP further includes the following specific processing: if it is determined that the wafer has slipped relative to the polishing head, the polishing abnormality can be recorded and the chemical mechanical polishing can be terminated.

[0132] In one possible implementation, the wafer monitoring method for non-metallic CMP also includes the following specific processing: during the process of the CMP equipment performing chemical mechanical polishing on the non-metallic layer of the wafer, determining whether the time end of the chemical mechanical polishing has been reached based on the torque value of the driving component; if the time end of the chemical mechanical polishing has been reached, then ending the chemical mechanical polishing.

[0133] The torque monitoring method is suitable for determining the endpoint of chemical mechanical polishing of the non-metallic layer of a wafer, and is particularly suitable for determining the endpoint of chemical mechanical polishing of the outermost non-metallic layer of two adjacent non-metallic layers of a wafer. Since the materials of the two non-metallic layers are different, the friction between the two non-metallic layers and the polishing pad during chemical mechanical polishing is also different, and thus the torque of the driving component is greatly different when the two non-metallic layers are in contact with the polishing pad during chemical mechanical polishing. After the outermost non-metallic layer is polished away, the other non-metallic layer is in contact with the polishing pad, and the torque value of the driving component increases, and thus the polishing endpoint can be monitored by monitoring the torque.

[0134] Based on this, in a specific embodiment, when the CMP equipment performs mechanical chemical polishing on the non-metallic layer of the wafer, it is determined whether it enters the first preset moment (the first preset moment may be the moment when the torque value starts to rise). If so, multiple groups of torque values ​​are continuously collected at each preset time interval (for example, 1s), each group of torque values ​​includes at least one torque value, and the torque mean of each group of torque values ​​is obtained, and it is determined whether the absolute error between the torque mean and the first torque value in the next group of torque values ​​is less than the first preset value (for example, ±0.05%). If so, the maximum moment of the motor torque value is obtained, and it is determined whether the difference between the torque mean values ​​of the two groups of torque values ​​adjacent to the torque mean value is greater than the second preset value (for example, 0.1%). If so, it means that the non-metallic layer to be polished has been almost polished. At this time, the current time can be determined as the time end point, and the chemical mechanical polishing is terminated. In addition, if the difference between the current time and the maximum moment of the motor torque value is greater than the protection time, the chemical mechanical polishing can also be terminated.

[0135] In the embodiment of the present application, chemical mechanical polishing is automatically terminated by monitoring the torque of the driving member, thereby reducing the possibility of over-polishing the wafer or insufficiently polishing the wafer.

[0136] In a possible implementation, during the process of chemical mechanical polishing of a non-metallic layer of a wafer by a CMP device, the time when the image collector captures the first image is the same as the time when the first torque value of the driving member is acquired.

[0137] Therefore, during the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP equipment, the acquisition of the first image and the acquisition of the torque value are started almost at the same time, which can avoid the situation where the acquisition of the first image starts too early than the acquisition of the torque value, or the acquisition of the torque value starts too early than the acquisition of the first image, thereby reducing the waste of resources such as equipment, manpower or electricity.

[0138] The embodiment of the present application also provides a wafer monitoring method for chemical mechanical polishing. The wafer monitoring method for chemical mechanical polishing can be applied to CMP equipment, etc., and the embodiment of the present application is not limited to this.

[0139] It should be noted that the width of the bow wave is greatly affected by the rotation speed of the polishing disk, the rotation speed of the polishing head, the liquid supply speed of the liquid supply arm, the ratio of the polishing liquid, the image acquisition position, etc. during the chemical mechanical polishing process. Therefore, the time values ​​or bow wave width values ​​in this application are all examples and are not used to limit the scope of protection of this application. Technical personnel in this field can make changes according to the actual process scenarios, which are all within the scope of protection of this application.

[0140] Figure 1 Schematic diagram of a CMP device according to an embodiment of the present application. Figure 1As shown, w is a wafer, and the CMP equipment is used to perform chemical mechanical polishing on the wafer, specifically, to perform chemical mechanical polishing on the metal layer or non-metal layer of the wafer, and the CMP equipment includes: a polishing disc 1, a polishing head bracket 2, a polishing head 3, a liquid supply arm, an image collector 4 (such as a high-speed camera, etc.) and a controller; a circular pad-shaped polishing pad 11 is arranged on one side of the polishing disc 1, and 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 bracket 2 is connected to the polishing head 3, and the polishing head 3 is located between the polishing head bracket 2 and the polishing pad 11, and the polishing head bracket 2 is used to drive the polishing head 3 to drive the wafer to abut against the polishing surface, specifically The metal layer or non-metal layer to be polished on the wafer is driven to abut against the polishing surface, and the polishing head 3 is driven to drive the wafer to rotate relative to the polishing pad 11 around the axis of the wafer, and the polishing head 3 is also driven to drive the wafer to reciprocate on the polishing surface along the radial direction of the polishing surface to perform chemical mechanical polishing on the wafer; the liquid supply arm is used to provide polishing liquid to the polishing pad 11 during the process of chemical mechanical polishing of the wafer; the image collector 4 is connected to the polishing head bracket 2, and the acquisition lens of the image collector 4 is facing the polishing pad 11 near 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 near the polishing head 3; the controller is used to execute the wafer monitoring method for chemical mechanical polishing.

[0141] Optionally, the shapes of the polishing head 3 and the polishing head bracket 2 can be set to be cylindrical, and the image collector 4 can be detachably connected or fixedly connected to the bottom edge of the polishing head bracket 2. During the chemical mechanical polishing process, since the axis of the polishing head bracket 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 bracket 2 to move back and forth by external force, the polishing head 3 will rotate around the axis of the wafer itself relative to the image collector 4, but the relative position between the polishing head 3 and the image collector 4 will not change, so that the image collector 4 can more stably capture the image of the bow wave on the polishing pad 11 near the polishing head 3, specifically, it can more stably capture the image of the bow wave on the polishing pad 11 near the bottom edge of the polishing head 3.

[0142] The wafer monitoring method for chemical mechanical polishing is described in detail below through multiple embodiments.

[0143] Fig.11 FIG. 1 is a flow chart of a wafer monitoring method for chemical mechanical polishing according to an embodiment of the present application. Fig.11 As shown, the wafer monitoring method for chemical mechanical polishing includes the following steps:

[0144] Step 1101: Acquire at least one first image captured by an image collector during chemical mechanical polishing of a wafer by a CMP device.

[0145] In a specific embodiment, during the process of chemical mechanical polishing of a wafer by a CMP device, an image collector can be controlled to periodically capture images of a bow wave near the bottom edge of a polishing head on a polishing pad, and all captured images are used as first images. The present application embodiment does not limit the image capture period of the image collector, for example, the image collector can be controlled to capture the first image at a shutter speed of 0.02s and an image capture frequency of 5Hz.

[0146] Step 1102: If the width of the bow wave in the at least one first image meets the second slip condition, it is determined that the wafer has slipped relative to the polishing head.

[0147] During the chemical mechanical polishing process, whether the wafer slips will directly affect the width of the bow wave on the polishing pad near the bottom edge of the polishing head. Specifically, when the wafer is not slipping, the polishing head abuts the wafer against the polishing pad, and there is a liquid film formed by the polishing liquid between the wafer and the polishing pad. At this time, the width of the bow wave in the first image collected is stable near the first value. When the wafer slips, it will cause a sudden change in the space under the polishing head, and the polishing liquid will switch from one steady state to another, so that the width of the bow wave in the first image collected at this time will change. For example, the width of the bow wave in the first image collected at this time is stable near the second value. After sliding out from under the polishing head, other polishing conditions remain almost unchanged, but the space between the polishing head and the polishing pad increases, and the deformation of the polishing pad caused by the pressure of the wafer between the polishing head and the polishing pad decreases, so that the flow rate of the polishing liquid between the polishing head and the polishing pad becomes larger, and the amount of polishing liquid accumulated on the polishing pad near the edge of the bottom surface of the polishing head becomes less. Therefore, compared with the first image collected when the wafer is not sliding, the width of the bow wave in the first image collected when the wafer is sliding is generally smaller, that is, the second value is generally smaller than the first value, for example, the first value is 8mm and the second value is 5mm, or, the first value is 12mm and the second value is 8mm, etc.

[0148] It should be noted that during the chemical mechanical polishing process, due to the certain volatility of the flowing polishing liquid itself and the fact that the polishing head will drive the wafer to move back and forth along the radial direction of the polishing pad, the width of the bow wave will fluctuate more regularly regardless of whether the wafer is sliding or not. In addition, the width of the bow wave will be stable near different values ​​when the wafer is not sliding and when the wafer is sliding. Therefore, the first and second values ​​mentioned above are both approximate values ​​of the width of the bow wave in the first image collected when the bow wave is relatively stable.

[0149] Based on this, in a specific embodiment, after acquiring the above-mentioned at least one first image, the width of the bow wave in each first image can be determined. When the width of the bow wave in the at least one first image acquired is small (for example, smaller than a certain threshold), it is determined that the width of the bow wave in the at least one first image meets the second slip condition, and then it is determined that the wafer has slipped 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 slip condition, and then it is determined that the wafer has not slipped relative to the polishing head, thereby realizing the monitoring of wafer slip.

[0150] Optionally, the width of the bow wave in the image can be obtained by binarizing the image, or by dividing the area of ​​the bow wave in the image (which can be obtained from image analysis software) by the actual arc length. The actual arc length can be the arc length of the polishing head within the image acquisition area of ​​the image collector. The specific method for determining the width of the bow wave in the image is not limited in the embodiments of the present application.

[0151] In an embodiment of the present application, during the process of chemical mechanical polishing of a wafer by a CMP device, at least one first image captured by an image collector is acquired. If the width of the bow wave in the at least one first image meets the second slip condition, it is determined that the wafer has slipped relative to the polishing head. Therefore, compared with monitoring the wafer slip by a relatively short-term change of the laser captured by an optical sensor, in an embodiment of the present application, the width of the bow wave near the polishing head on the polishing pad is used to monitor whether the wafer is slipping. When the wafer slips, the width of the bow wave is almost always stable in a small state, so that the width of the bow wave in the at least one first image captured at most times when the wafer is slipping meets the second slip condition, reducing the possibility of false alarms and missed alarms when monitoring the wafer slip, so that the monitoring results of the wafer slip monitoring are more accurate.

[0152] In a possible implementation, the image collector is used to collect an image of the bow wave at a target portion of the polishing pad close to the polishing head, where the target portion is a portion of the polishing head close to the liquid supply arm.

[0153] 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, with the lens of the image collector facing the target portion of the polishing pad close to the polishing head. Thus, the image collector can collect the bow wave as close to the position of the liquid supply arm as possible, and the width of the collected bow wave is larger, and the collected bow wave is more obvious, which can make the monitoring results of the wafer slide more accurate.

[0154] Optionally, the image collector may be connected to a jetting assembly for cleaning the image collector to reduce the influence of the polishing liquid splashed onto the image collector on the clarity of the image collected by the image collector.

[0155] Optionally, an inert dye or an inert fluorescent dye can be added to the polishing liquid for collection; if a fluorescent dye is added to the polishing liquid, the chemical mechanical polishing process should be in a closed light-proof environment, and an ultraviolet lamp should be added to the environment to make the bow wave in the image collected by the image collector clearer.

[0156] The method of determining whether the width of the bow wave in the at least one first image meets the second slider condition has been described in the above-mentioned embodiment of the wafer monitoring method for metal CMP, and will not be repeated here in the embodiment of the present application.

[0157] Corresponding to the above-mentioned embodiment of the wafer monitoring method for metal CMP, as Figure 1 As shown, the CMP device includes: a polishing plate 1, a polishing head 3, a liquid supply arm, an image collector 4, an eddy current sensor and a controller;

[0158] A polishing pad 11 is provided on one side of the polishing disc 1;

[0159] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11, and drive the wafer to move relative to the polishing pad 11, so as to perform chemical mechanical polishing on the wafer;

[0160] A liquid supply arm, used to supply polishing liquid to the polishing pad 11 during chemical mechanical polishing of the wafer;

[0161] An image collector 4 is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3;

[0162] An eddy current sensor, used for collecting wafer signals when the eddy current sensor is opposite to the wafer in a direction perpendicular to the polishing pad 11;

[0163] A controller is used to execute the above-mentioned wafer monitoring method for metal CMP.

[0164] It should be noted that the CMP equipment of this embodiment is used to implement the corresponding wafer monitoring method for metal CMP in the aforementioned method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0165] Corresponding to the above-mentioned embodiment of the wafer monitoring method for non-metallic CMP, as Figure 1 As shown, the CMP device includes: a polishing plate 1, a polishing head 3, a liquid supply arm, an image collector 4 and a controller;

[0166] A polishing pad 11 is provided on one side of the polishing disc 1;

[0167] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11, and drive the wafer to move relative to the polishing pad 11, so as to perform chemical mechanical polishing on the wafer;

[0168] A liquid supply arm, used to supply polishing liquid to the polishing pad 11 during chemical mechanical polishing of the wafer;

[0169] An image collector 4 is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3;

[0170] A driving member, used to control the rotation of the polishing pad or the polishing head;

[0171] A controller is used to execute the above-mentioned wafer monitoring method for non-metal CMP.

[0172] In a specific embodiment, the CMP device may be the CMP device described in the above embodiment of the wafer monitoring method for non-metallic CMP, and the controller is used to execute the above wafer monitoring method for non-metallic CMP.

[0173] It should be noted that the CMP equipment of this embodiment is used to implement the corresponding wafer monitoring method for non-metallic CMP in the aforementioned method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0174] Corresponding to the above-mentioned wafer monitoring method embodiment for chemical mechanical polishing, as shown in Figure 1 As shown, the CMP device includes: a polishing plate 1, a polishing head 3, a liquid supply arm, an image collector 4 and a controller;

[0175] A polishing pad 11 is provided on one side of the polishing disc 1;

[0176] The polishing head 3 is used to drive the wafer to abut against the polishing surface of the polishing pad 11, and drive the wafer to move relative to the polishing pad 11, so as to perform chemical mechanical polishing on the wafer;

[0177] A liquid supply arm, used to supply polishing liquid to the polishing pad 11 during chemical mechanical polishing of the wafer;

[0178] An image collector 4 is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad 11 near the polishing head 3;

[0179] A controller is used to execute the above-mentioned wafer monitoring method for chemical mechanical polishing.

[0180] In a specific embodiment, the CMP device may be the CMP device described in the above embodiment of the wafer monitoring method for chemical mechanical polishing, and the controller is used to execute the above embodiment of the wafer monitoring method for chemical mechanical polishing.

[0181] It should be noted that the CMP equipment of this embodiment is used to implement the corresponding wafer monitoring method for chemical mechanical polishing in the aforementioned method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0182] The present application also provides a computer-readable storage medium storing instructions for causing a machine to execute the wafer monitoring method for metal CMP, the wafer monitoring method for non-metal CMP, or the wafer monitoring method for chemical mechanical polishing as described herein. Specifically, a system or device equipped with a storage medium may be provided, on which a software program code for implementing the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device reads out and executes the program code stored in the storage medium.

[0183] In this case, the program code read from the storage medium itself can implement the function of any one of the above embodiments, so the program code and the storage medium storing the program code constitute part of the present application.

[0184] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, 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.

[0185] An embodiment of the present application also provides a computer program product, including computer instructions, which instruct a computing device to perform any corresponding operation in the above-mentioned multiple method embodiments.

[0186] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used to train the model, data used 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 fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0187] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0188] The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as a computer code originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a special-purpose processor or programmable or special-purpose hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown here, the execution of the code converts the general-purpose computer into a special-purpose computer for executing the method shown here.

[0189] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used to train the model, data used 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 fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0190] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for specific applications, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0191] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field 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 scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

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

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

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

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

5. The method according to claim 2, characterized in that: The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first change data according to the plurality of first images; It is determined whether the width of the bow wave in the plurality of first images meets the second slide condition according to the first change data.

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

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

8. The method according to claim 2, characterized in that: The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: During the process of chemical mechanical polishing of the metal layer of the wafer by the CMP device, a plurality of second images acquired by the image acquisition device during a control time period in which the wafer does not slip relative to the polishing head; determining the second change data according to the plurality of second images; determining the first change data according to the plurality of first images; The second change data is compared with the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slide condition.

9. The method according to claim 2, characterized in that: The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period, and the first change data is a change curve; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and a comparison result of the first change data comprises: Determining the variation curve in a coordinate system according to the plurality of first images; The change curve is converted into the time domain and subjected to Fourier transformation to obtain a transformation result; Acquire multiple superimposed waveforms from the transformation results; If the peak value of the waveform with the largest peak value among the multiple waveforms is smaller than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is smaller than the second peak value, it is determined that the width of the bow wave in the multiple first images meets the second slide condition, wherein the first peak value is larger than the second peak value.

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

11. A wafer monitoring method for non-metallic CMP, characterized in that: include: During the process of chemical mechanical polishing of a non-metallic layer of a wafer by a CMP device, at least one first image acquired by an image acquisition device and at least one torque value of a driving member are acquired, wherein the CMP device comprises a polishing head, a polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a polishing surface of the polishing pad, the liquid supply arm is used to provide polishing liquid to the polishing surface, the image acquisition device is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head, and the driving member is used to control the rotation of the polishing pad or the polishing head; determining a target torque value according to the at least one torque value; and determining that the at least one torque value meets a third sliding sheet condition if the target torque value is less than a torque threshold; If the at least one torque value satisfies the third sliding condition, determining whether the width of the bow wave in the at least one first image satisfies the second sliding condition; If the width of the bow wave in the at least one first image meets the second slip condition, determining that the wafer has slipped relative to the polishing head; If it is determined that the wafer has slipped relative to the polishing head, then terminating the chemical mechanical polishing; The method further comprises: During the process of the CMP device performing chemical mechanical polishing on the non-metallic layer of the wafer, whether the time end of the chemical mechanical polishing has been reached is determined according to the torque value of the driving component; if the time end of the chemical mechanical polishing has been reached, the chemical mechanical polishing is terminated.

12. The method according to claim 11, characterized in that The method further comprises: Determine whether the width of the bow wave in the at least one first image meets the second sliding condition based on at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data, wherein the first bow wave width is a width obtained based on the width of the bow wave in the at least one first image, the first change data is used to indicate how the width of the bow wave in the first image changes with the time when the first image is collected during a monitoring time period, and the second change data is used to indicate how the width of the bow wave in the second image acquired by the image acquirer changes with the time when the second image is collected during a control time period when the wafer does not slip relative to the polishing head.

13. The method according to claim 12, characterized in that The determining whether the width of the bow wave in the at least one first image meets the second slide condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first bow wave width based on the width of the bow wave in the at least one first image; If the first bow wave width is less than a first width threshold, it is determined that the width of the bow wave in the at least one first image meets the second slide condition.

14. The method according to claim 13, characterized in that The method further comprises: During the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device, acquiring at least one third image acquired by the image acquisition device when the wafer does not slip relative to the polishing head; determining a second bow wave width based on the width of the bow wave in the at least one third image; The first width threshold is determined according to the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

15. The method according to claim 12, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first change data according to the plurality of first images; It is determined whether the width of the bow wave in the plurality of first images meets the second slide condition according to the first change data.

16. The method according to claim 15, characterized in that The step of determining, according to the first change data, whether the width of the bow wave in the plurality of first images meets the second slide condition comprises: Dividing the monitoring time period into a plurality of continuous unit time periods, wherein the length of each unit time period is the same; Determining a characteristic value corresponding to each of the unit time periods according to the first change data, wherein the characteristic value corresponding to the unit time period is used to indicate a change amount of the bow wave width corresponding to the unit time period; It is determined whether the width of the bow waves in the plurality of first images meets the second sliding sheet condition according to the characteristic values ​​corresponding to the plurality of unit time periods.

17. The method according to claim 16, characterized in that The determining, according to the characteristic values ​​corresponding to the plurality of unit time periods, whether the width of the bow waves in the plurality of first images meets the second slide condition comprises: Determining whether there is a target time period within the monitoring time period according to the characteristic values ​​corresponding to the multiple unit time periods, wherein the target time period includes a continuous target number of unit time periods, and the sum of the characteristic values ​​corresponding to the target number of unit time periods exceeds a first threshold; If a target time period exists within the monitoring time period, and the sum of the characteristic values ​​corresponding to the unit time periods before the target time period is less than a second threshold, and a third bow wave width determined based on at least part of the first change data after the target time period is less than a second width threshold, it is determined that the width of the bow wave in the multiple first images meets the second slide condition.

18. The method according to claim 12, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: During the process of chemical mechanical polishing of the non-metallic layer of the wafer by the CMP device, acquiring a plurality of second images acquired by the image acquisition device during a control time period in which the wafer does not slip relative to the polishing head; determining the second change data according to the plurality of second images; determining the first change data according to the plurality of first images; The second change data is compared with the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slide condition.

19. The method according to claim 12, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period, and the first change data is a change curve; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and a comparison result of the first change data comprises: Determining the variation curve in a coordinate system according to the plurality of first images; The change curve is converted into the time domain and subjected to Fourier transformation to obtain a transformation result; Acquire multiple superimposed waveforms from the transformation results; If the peak value of the waveform with the largest peak value among the multiple waveforms is smaller than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is smaller than the second peak value, it is determined that the width of the bow wave in the multiple first images meets the second slide condition, wherein the first peak value is larger than the second peak value.

20. The method according to claim 11, characterized in that During the process of the CMP device performing chemical mechanical polishing on the non-metallic layer of the wafer, the time when the image collector collects the first first image is the same as the time when the first torque value of the driving component is acquired.

21. A wafer monitoring method for chemical mechanical polishing, characterized in that: include: During the process of chemical mechanical polishing of a wafer by a CMP device, at least one first image acquired by an image collector is acquired, wherein the CMP device comprises a polishing head, a polishing pad and a liquid supply arm, the polishing head is used to drive the wafer to abut against a polishing surface of the polishing pad, the liquid supply arm is used to provide polishing liquid to the polishing surface, and the image collector is used to acquire an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; determining 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, 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 how the width of the bow wave in the first image changes with the time when the first image is collected during a monitoring time period, and the second change data is used to indicate how the width of the bow wave in the second image collected by the image collector changes with the time when the second image is collected during a control time period when the wafer does not slip relative to the polishing head; If the width of the bow wave in the at least one first image meets a second slip condition, it is determined that the wafer has slipped relative to the polishing head.

22. The method according to claim 21, characterized in that The determining whether the width of the bow wave in the at least one first image meets the second slide condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first bow wave width based on the width of the bow wave in the at least one first image; If the first bow wave width is less than a first width threshold, it is determined that the width of the bow wave in the at least one first image meets the second slide condition.

23. The method according to claim 22, characterized in that The method further comprises: During the process of chemical mechanical polishing of the wafer by the CMP device, acquiring at least one third image acquired by the image acquisition device when the wafer does not slip relative to the polishing head; determining a second bow wave width based on the width of the bow wave in the at least one third image; The first width threshold is determined according to the second bow wave width, wherein the first width threshold is less than or equal to the second bow wave width.

24. The method according to claim 23, characterized in that The first width threshold is positively correlated with the second bow wave width.

25. The method according to claim 21, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: determining the first change data according to the plurality of first images; It is determined whether the width of the bow wave in the plurality of first images meets the second slide condition according to the first change data.

26. The method according to claim 25, characterized in that The step of determining, according to the first change data, whether the width of the bow wave in the plurality of first images meets the second slide condition comprises: Dividing the monitoring time period into a plurality of continuous unit time periods, wherein the length of each unit time period is the same; Determining a characteristic value corresponding to each of the unit time periods according to the first change data, wherein the characteristic value corresponding to the unit time period is used to indicate a change amount of the bow wave width corresponding to the unit time period; It is determined whether the width of the bow waves in the plurality of first images meets the second sliding sheet condition according to the characteristic values ​​corresponding to the plurality of unit time periods.

27. The method according to claim 26, characterized in that The determining, according to the characteristic values ​​corresponding to the plurality of unit time periods, whether the width of the bow waves in the plurality of first images meets the second slide condition comprises: Determining whether there is a target time period within the monitoring time period according to the characteristic values ​​corresponding to the multiple unit time periods, wherein the target time period includes a continuous target number of unit time periods, and the sum of the characteristic values ​​corresponding to the target number of unit time periods exceeds a first threshold; If a target time period exists within the monitoring time period, and the sum of the characteristic values ​​corresponding to the unit time periods before the target time period is less than a second threshold, and a third bow wave width determined based on at least part of the first change data after the target time period is less than a second width threshold, it is determined that the width of the bow wave in the multiple first images meets the second slide condition.

28. The method according to claim 26, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and the comparison result of the first change data comprises: During the process of chemical mechanical polishing of the wafer by the CMP device, acquiring a plurality of second images acquired by the image acquisition device during a control time period in which the wafer does not slip relative to the polishing head; determining the second change data according to the plurality of second images; determining the first change data according to the plurality of first images; The second change data is compared with the first change data to determine whether the width of the bow wave in the plurality of first images meets the second slide condition.

29. The method according to claim 26, characterized in that The at least one first image is a plurality of first images acquired by the image collector within a monitoring time period, and the first change data is a change curve; determining whether the width of the bow wave in the at least one first image meets the second sliding condition according to at least one of the first bow wave width, the first change data, the second change data and a comparison result of the first change data comprises: Determining the variation curve in a coordinate system according to the plurality of first images; The change curve is converted into the time domain and subjected to Fourier transformation to obtain a transformation result; Acquire multiple superimposed waveforms from the transformation results; If the peak value of the waveform with the largest peak value among the multiple waveforms is smaller than the first peak value, and the peak value of the waveform with the smallest peak value among the multiple waveforms is smaller than the second peak value, it is determined that the width of the bow wave in the multiple first images meets the second slide condition, wherein the first peak value is larger than the second peak value.

30. The method according to any one of claims 25 to 29, characterized in that The image collector is used to collect an image of a bow wave at a target portion of the polishing pad close to the polishing head, where the target portion is a portion of the polishing head close to the liquid supply arm.

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

32. A CMP device, characterized in that: include: Polishing disc, polishing head, liquid supply arm, image acquisition device, drive unit and controller; A polishing pad is provided on one side of the polishing disc; The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; The liquid supply arm is used to supply polishing liquid to the polishing pad during chemical mechanical polishing of the wafer; The image collector is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; The driving member is used to control the polishing pad or the polishing head to rotate; The controller is used to execute the wafer monitoring method for non-metallic CMP as described in any one of claims 11-20.

33. A CMP device, characterized in that: include: Polishing disc, polishing head, liquid supply arm, image acquisition device and controller; A polishing pad is provided on one side of the polishing disc; The polishing head is used to drive the wafer to abut against the polishing surface of the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; The liquid supply arm is used to supply polishing liquid to the polishing pad during chemical mechanical polishing of the wafer; The image collector is used to collect an image of a bow wave formed by the polishing liquid on the polishing pad near the polishing head; The controller is used to execute the wafer monitoring method for chemical mechanical polishing as described in any one of claims 21-30.

34. A computer storage medium, characterized in that A computer program is stored thereon, which, when executed by a processor, implements a wafer monitoring method for metal CMP as described in any one of claims 1 to 10, or a wafer monitoring method for non-metal CMP as described in any one of claims 11 to 20, or a wafer monitoring method for chemical mechanical polishing as described in any one of claims 21 to 30.

35. A computer program product, characterized in that The method comprises computer instructions for instructing a computing device to execute a wafer monitoring method for metal CMP as described in any one of claims 1 to 10, or a wafer monitoring method for non-metal CMP as described in any one of claims 11 to 20, or a wafer monitoring method for chemical mechanical polishing as described in any one of claims 21 to 30.

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