A method and device for detecting wear of a polishing pad, an electronic device, and a storage medium

Abstract

The application provides a polishing pad loss detection method and device, electronic equipment and storage medium; the method comprises the following steps: obtaining an endpoint detection curve; the endpoint detection curve is used to represent the corresponding relationship between the polishing time and the light intensity parameter in the process of chemical mechanical grinding of the target wafer by using the polishing pad; feature point extraction is performed on the endpoint detection curve to obtain an extraction result; and the loss degree of the polishing pad is determined according to the extraction result. In this way, the real-time wear condition of the polishing pad can be accurately monitored, so that the polishing pad can be replaced at the best time point, the loss misjudgment caused by different process differences can be avoided, and the potential grinding life of the polishing pad can be fully explored.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method, apparatus, electronic device, and storage medium for detecting the wear of polishing pads. Background Technology

[0002] In the Chemical Mechanical Polishing (CMP) process, the material surface achieves global planarization through the combined action of chemical reaction and mechanical abrasion. The chemical components in the polishing slurry first react with the material surface to generate a softened layer that is easy to remove; subsequently, under the synergistic mechanical action of the polishing pad and abrasive particles, this softened layer is effectively removed, thereby obtaining a surface smoothness that meets the process requirements.

[0003] However, in actual production, due to the different wear characteristics of polishing pads for different products, it is difficult to accurately monitor and control the wear degree of polishing pads.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This application provides a method, apparatus, device, and computer-readable storage medium for detecting the wear of polishing pads. It can determine the degree of wear of polishing pads by acquiring an endpoint detection curve and determining the time interval between feature points on the endpoint detection curve, thereby accurately monitoring the real-time wear status of polishing pads.

[0006] The technical solution of this application embodiment is implemented as follows: In a first aspect, embodiments of this application provide a method for detecting the wear of a polishing pad, the method comprising: Obtain the endpoint detection curve; the endpoint detection curve is used to represent the relationship between polishing time and light intensity parameters during the chemical mechanical polishing of the target wafer using the polishing pad; Feature points are extracted from the endpoint detection curve to obtain the extraction results; Based on the extraction results, the degree of wear of the polishing pad is determined.

[0007] In some embodiments, determining the wear level of the polishing pad based on the extraction result includes: If the extraction result is: the time interval between the latest extracted feature point and a historical feature point meets the first preset condition, the wear level of the polishing pad is determined to be in the middle and late stages; If the extraction result is: no new feature point is extracted after a first time threshold interval from the last extraction of the feature point, the wear degree of the polishing pad is determined to be in the later stage.

[0008] In some embodiments, the first preset condition includes: the time interval between the most recently extracted feature point and the historical feature point is greater than a second time threshold; the second time threshold is an upper limit value of the time interval between two feature points corresponding to the condition that the polishing pad has not worn. Alternatively, the newly extracted feature point and the historical feature point are respectively the first feature point and the second feature point in the endpoint detection curve, the time interval between the first feature point and the second feature point in the endpoint detection curve is the first time interval, the time interval between the first feature point and the second feature point in the endpoint detection curve corresponding to the previous target wafer is the second time interval, and the first preset condition includes: the value of the first time interval being greater than the second time interval exceeds the third time threshold.

[0009] In some embodiments, the historical feature points are the adjacent feature points preceding the most recently extracted feature point.

[0010] In some embodiments, the endpoint detection curve is a first type curve or a second type curve, wherein the first type curve is a curve obtained during the grinding of the same material layer of the target wafer, and the second type curve is a curve obtained during the grinding of different material layers of the wafer; In the first type of curve, the feature point is the point corresponding to the peak or trough; In the second type of curve, the feature point is an inflection point.

[0011] In some embodiments, when the endpoint detection curve is the first type of curve, any two adjacent feature points in the first type of curve constitute a sub-time period. The second time threshold includes at least one second sub-time threshold, each second sub-time threshold corresponds to a sub-time period, and the first preset condition specifically includes: the time interval between the latest extracted feature point and the historical feature point is greater than the second sub-time threshold corresponding to the sub-time period; Alternatively, the third time threshold includes at least one third sub-time threshold, each of the third sub-time thresholds corresponding to a sub-time period, and the first preset condition specifically includes: the value of the first time interval being greater than the second time interval exceeds the third sub-time threshold corresponding to the sub-time period.

[0012] In some embodiments, determining the wear level of the polishing pad based on the extraction result further includes: The extraction result is as follows: the time interval between any two adjacent feature points in the endpoint detection curve is the first sub-time interval, and the time interval between any two adjacent feature points in the endpoint detection curve corresponding to the previous target wafer is the second sub-time interval; If the difference between the mean of all first sub-time intervals and the mean of all second sub-time intervals is greater than the fourth time threshold, the wear level of the polishing pad is determined to be in the middle to late stage.

[0013] In some embodiments, when the wear level of the polishing pad is in the middle to late stage, the method further includes: issuing an alarm; If the polishing pad is in a later stage of wear, the method further includes stopping the polishing process.

[0014] Secondly, embodiments of this application provide a polishing pad wear detection device, comprising: The acquisition unit is configured to acquire the endpoint detection curve; the endpoint detection curve is used to represent the relationship between the polishing time and the light intensity parameter during the chemical mechanical polishing of the target wafer using the polishing pad. The extraction unit is configured to extract feature points from the endpoint detection curve to obtain the extraction result. The detection unit is configured to determine the degree of wear of the polishing pad based on the extraction results.

[0015] In some embodiments, the acquisition unit is an endpoint detection device; the extraction unit is a signal converter.

[0016] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor; Memory is used to store executable instructions or computer programs. The processor, when executing computer-executable instructions or computer programs stored in the memory, implements the method provided in the embodiments of this application.

[0017] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by at least one processor, implements the steps of the wear detection method for a polishing pad as described in any of the first aspects.

[0018] The embodiments of this application have the following beneficial effects: This application provides a method for detecting the wear of a polishing pad. First, during the chemical mechanical polishing process of the polishing pad on the target wafer, the correspondence between polishing time and light intensity parameters is obtained to obtain an endpoint detection curve. Then, feature points on the endpoint detection curve are extracted, and the extraction results can characterize the wear degree of the polishing pad. Specifically, when the wear degree of the polishing pad reaches the middle and late stages, the time interval between feature points will increase significantly, and when the wear degree of the polishing pad reaches the late stage, it will be impossible to extract clear feature points. In this way, by using the feature points on the endpoint detection curve, the real-time wear condition of the polishing pad can be accurately monitored, thereby allowing for replacement at the optimal time point and avoiding misjudgment of wear caused by differences in different processes. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a method for detecting the wear of a polishing pad provided in an embodiment of this application; Figure 2 This is a schematic diagram illustrating the working principle of a chemical mechanical polishing endpoint detection device provided in an embodiment of this application; Figure 3 This is a schematic diagram of an endpoint detection curve provided in an embodiment of this application; Figure 4 This is a schematic diagram of the first type of curve provided in the embodiments of this application; Figure 5 This is a schematic diagram of the second type of curve provided in the embodiments of this application; Figure 6 This is a schematic diagram of the endpoint detection curves corresponding to polishing pads with different wear levels provided in the embodiments of this application; Figure 7 This is a comparative illustration of the endpoint detection curves provided in the embodiments of this application. Figure 1 ; Figure 8 This is a comparative illustration of the endpoint detection curves provided in the embodiments of this application. Figure 2 ; Figure 9 This is a comparative illustration of the endpoint detection curves provided in the embodiments of this application. Figure 3 ; Figure 10 This is a schematic diagram of the composition structure of a polishing pad wear detection device provided in an embodiment of this application; Figure 11 This is a schematic diagram of the composition structure of another polishing pad wear detection device provided in an embodiment of this application; Figure 12 This is a schematic diagram of the composition structure of an electronic device provided in an embodiment of this application.

[0020] It should be noted that the terms "first" and "second" mentioned above are only used to distinguish between different options and do not represent the degree of superiority or inferiority of the options or their priority in the implementation process. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It is understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the disclosure. It should also be noted that, for ease of description, only the parts relevant to the disclosure are shown in the accompanying drawings. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application. In the following description, references to "some embodiments" describe a subset of all possible embodiments; however, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict. It should be noted that the terms "first, second, third, fourth" used in the embodiments of this application are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third, fourth" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0023] End-point detection (EPD) for wafers primarily functions only to monitor overall wafer thickness variations and interface transitions between different film layers, resulting in a relatively limited detection scope. Currently, the commonly used standardized control methods based on polishing time or polishing cycles cannot accurately reflect the actual wear state of the polishing pads, which directly impact the uniformity and consistency of wafer polishing. Excessive wear of the polishing pads can lead to abnormal wafer polishing, resulting in serious quality issues such as product scrap. Therefore, there is an urgent need to develop a method that can accurately assess the wear state of polishing pads to improve process controllability and product yield.

[0024] Based on this, this application provides a method for detecting the wear of polishing pads. The basic idea of ​​this method is as follows: First, during the chemical mechanical polishing of the target wafer using the polishing pad, the relationship between polishing time and light intensity parameters is obtained to obtain an endpoint detection curve. Then, feature points on the endpoint detection curve are extracted, and the degree of wear of the polishing pad is determined based on the time interval between the extracted feature points. In this way, the real-time wear condition of the polishing pad can be accurately monitored through the feature points on the endpoint detection curve, allowing for replacement at the optimal time and avoiding misjudgments of wear caused by differences in different manufacturing processes.

[0025] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0026] In one embodiment of this application, see Figure 1 This illustrates a flowchart of a method for detecting the wear of a polishing pad according to an embodiment of this application. Figure 1 As shown, the method may include: S10: Obtain the endpoint detection curve.

[0027] It should be noted that the endpoint detection curve can be obtained through an endpoint detection device. The endpoint detection curve represents the relationship between polishing time and light intensity parameters during the chemical mechanical polishing of the target wafer using a polishing pad.

[0028] Here, the horizontal axis of the endpoint detection curve represents the polishing time (hereinafter referred to as time), and the vertical axis represents the light intensity parameter (hereinafter referred to as light intensity). Each data point (time, light intensity) on the endpoint detection curve represents the intensity of the light signal reflected from the surface of the target wafer and modulated by the two-beam interference model at a precise moment in the polishing process.

[0029] It should be noted that the two-beam interference model used here is often used to explain the principle of periodic oscillation of light intensity in CMP endpoint detection.

[0030] It should be further explained that, such as Figure 2 As shown, this diagram illustrates the working principle of a chemical mechanical polishing endpoint detection device provided in this application embodiment. Incident light irradiates the thin film surface of the target wafer, generating two main reflected beams, A and B. Reflected beam A is reflected from the upper surface of the thin film on the target wafer, with an intensity of I. A The reflected light B penetrates the thin film of the target wafer, is reflected from the lower interface, and then exits, with an intensity of I. B When reflected light A and reflected light B meet, they interfere. Whether the interference is constructive (bright) or destructive (dim) depends on their optical path difference, i.e., the phase difference θ. Figure 2In the figure, d represents the thickness of the thin film layer being polished in the target wafer, and Δd represents the thickness of the thin film layer being polished in the target wafer that has been ground away.

[0031] The light intensity parameter is obtained from the intensity (light strength) of the two interfering reflected beams and the phase difference between the two reflected beams. The formula for calculating the light intensity parameter I is:

[0032] Among them, I A Indicates the intensity of reflected light A; I B θ represents the intensity of reflected light B; θ represents the phase difference between reflected light A and reflected light B; n represents the refractive index of the thin film layer being polished in the target wafer; d represents the polishing thickness of the thin film layer; and λ represents the wavelength of the probe laser.

[0033] For example, when polishing the copper layer of a target wafer, I A I represents the light intensity reflected from the copper-polishing fluid / air interface. B This indicates the intensity of light reflected from the interface between the copper and the underlying barrier layer.

[0034] The two reflected beams, A and B, originate from the same incident beam but are reflected at different interfaces. Their intensities I... A and I B Depending on the reflectivity of the corresponding interface (which is related to the refractive index of the material), typically I A and I B They are not equal, and I A and I B The process remains essentially unchanged throughout the polishing process (assuming the thin film material of the target wafer is uniform).

[0035] like Figure 3 As shown, this diagram illustrates an endpoint detection curve provided in an embodiment of this application. During polishing, as the grinding thickness d decreases, the light intensity parameter decreases periodically (cosine wave) over time. Therefore, the stability of the polishing pad can be determined by capturing the time difference ΔT between the peak T1 and the trough T2. As ΔT begins to increase, it indicates that the polishing pad has worn out. If the time exceeds a preset threshold, it means that the pad is unusable, thus achieving real-time detection of the wear condition of the polishing pad.

[0036] S11: Extract feature points from the endpoint detection curve to obtain the extraction results.

[0037] It should be noted that in the endpoint detection process of chemical mechanical polishing, the original light intensity-time curve is merely a waveform containing noise. It is necessary to extract quantitative indicators with clear physical meaning from it. Therefore, this embodiment can add a signal converter or similar device to the endpoint detection device. The signal converter can identify specific inflection points, abrupt changes, and other characteristic points of the curve. By monitoring the changes between these characteristic points, process drift (such as changes in polishing rate) or abrupt changes (such as equipment malfunctions or the expiration of consumable lifespan) can be observed. Process drift is typically caused by the natural aging of the polishing pad (such as polishing pad wear) or the slow shift in equipment parameters; the changes in characteristic points are gradual and trend-based. Abrupt changes are typically caused by equipment failure or significant interference; the changes in characteristic points are sudden, abnormal, and do not conform to expected patterns.

[0038] Here, the endpoint detection curve is either a first-type curve or a second-type curve. The first-type curve is the curve obtained during the grinding of the same material layer of the target wafer, and the second-type curve is the curve obtained during the grinding of different material layers of the wafer. In the first type of curve, the characteristic point is the point corresponding to the peak or trough; In the second type of curve, the characteristic point is the inflection point.

[0039] It should be noted that, for the first type of curve, the horizontal axis represents the polishing time, and the vertical axis represents the light intensity parameter. Any point on the curve represents the intensity of a specific wavelength of light reflected from the surface of the target wafer being polished at a specific moment during polishing. For the second type of curve, the horizontal axis represents the polishing time, and the vertical axis represents the light intensity parameter. Any point on the curve represents the intensity of a specific wavelength of light reflected from the surface of the target wafer being polished at a specific moment during polishing.

[0040] It should be noted that, as Figure 4 As shown, this diagram illustrates a schematic of the first type of curve provided in an embodiment of this application. During the grinding process of the same material layer on the target wafer, since the refractive index n of the material layer is constant, the polishing rate is stable, the grinding thickness d decreases uniformly, and the phase difference θ between reflected light A and reflected light B changes continuously, successively satisfying the conditions of constructive interference-destructive interference-constructive interference, and the light intensity parameter... The light intensity parameter I is in I max and I min The curve exhibits periodic oscillations, therefore, when the polishing pad is not worn, the first type of curve displays a perfect cosine oscillation. Since a perfect cosine oscillation contains several peaks and troughs, it can be concluded that, when the polishing pad is in good condition and not worn, the first type of curve has multiple characteristic points. For example... Figure 4 As shown in the figure, the position of “□” represents the extracted feature point.

[0041] It should be noted that, as Figure 5 As shown, this illustrates a schematic diagram of the second type of curve provided in an embodiment of this application. During the grinding process of different material layers on the target wafer, since the target wafer has a stop layer, the material layer before the stop layer is primarily a metal layer. The metal layer is very thick, and metals have a strong absorption effect on light; therefore, the I at the lower interface of this metal layer... B The attenuation within this metal layer is severe, leading to I at the lower interface of this metal layer. B The light intensity is extremely weak, so before the stop layer is reached, the light intensity parameter I is approximately equal to the light intensity of the upper surface of the metal layer. A The second type of curve is initially stable. When the metal layer is ground to a very thin thickness, approaching the stop layer, the I value at the lower interface of the metal layer... B Enhanced, sufficient to connect with the upper surface I A Significant interference occurs; due to the large difference in refractive index (n) between the metal layer and the stop layer, the phase difference between the two reflected beams is close to π, resulting in primarily destructive interference; the light intensity parameter monotonically and sharply decreases from the maximum value of constructive interference to the minimum value of destructive interference, with a significant drop in the mid-stage of the second-type curve. When the metal layer is completely ground away, exposing a flat and uniform stop layer, the signal becomes a stable reflection from the upper surface of the stop layer, and the light intensity parameter stabilizes again at a new level, with the second-type curve remaining stable in the later stage. In summary, it can be seen that when the polishing pad is not worn, the second-type curve exhibits a stable early stage, a significant drop in the mid-stage, and a stable later stage. Therefore, it can be concluded that when the polishing pad is in good condition and not worn, the number of characteristic points of the second-type curve is two. Figure 5 As shown in the figure, the position of “□” represents the extracted feature point.

[0042] It should be further explained that constructive interference refers to the precise alignment of the peaks and troughs of reflected light A and reflected light B (i.e., the phase difference is 0 or an integer multiple of 2π), in which case they will enhance each other, and the intensity of the resulting composite light wave will reach its maximum value. Destructive interference refers to the precise alignment of the peaks of reflected light A and the troughs of reflected light B (i.e., the phase difference is π or an odd multiple of π), in which case they will weaken each other, and the intensity of the resulting composite light wave will reach its minimum value.

[0043] S12: Determine the degree of wear of the polishing pad based on the extraction results.

[0044] It should be noted that feature points on the endpoint detection curve and the time intervals between feature points can be extracted by a signal converter or other devices or equipment with similar functions.

[0045] In some embodiments, if the extraction result is that the time interval between the latest extracted feature point and a historical feature point meets the first preset condition, the wear level of the polishing pad is determined to be in the middle or late stage. If the extraction result is: no new feature points are extracted after the first time threshold interval since the last feature point was extracted, the wear level of the polishing pad is determined to be in the later stage.

[0046] It should be noted that when the polishing pad is in the middle or late stage of wear, an alarm will be issued, but the polishing pad can still be used; when the polishing pad is in the late stage of wear, grinding will stop, and the polishing pad needs to be replaced in time.

[0047] It should also be noted that historical feature points are any feature points prior to the most recently extracted feature point.

[0048] Specifically, the first preset condition includes: the time interval between the newly extracted feature point and the historical feature point is greater than the second time threshold; the second time threshold is the upper limit of the time interval between two feature points when the polishing pad has not worn out. Alternatively, the newly extracted feature point and the historical feature point are respectively the first feature point and the second feature point in the endpoint detection curve, the time interval between the first feature point and the second feature point in the endpoint detection curve is the first time interval, and the time interval between the first feature point and the second feature point in the endpoint detection curve corresponding to the previous target wafer is the second time interval. Correspondingly, the first preset condition includes: the value of the first time interval being greater than the second time interval exceeds the third time threshold.

[0049] In one example, such as Figure 6 As shown, Figure 6 In the figure, (a) represents the endpoint detection curve when the polishing pad has not worn. Figure 6 (b) in the figure represents the endpoint detection curve when the polishing pad is worn and the wear level is in the middle to late stage. Figure 6 (c) in the figure represents the endpoint detection curve when the polishing pad is worn and the wear level is in the later stage.

[0050] Figure 6 In the diagram, the position of the "□" in each image represents the extracted feature points (feature points F1, F2, F3, F4), where F4 represents the most recently extracted feature point, and F1, F2, and F3 represent three historical feature points. For example... Figure 6 In (a), the time interval between the fourth feature point F4 on the endpoint detection curve and the historical feature point F1 is the second time threshold T; as shown in (a), Figure 6 In (b), the most recently extracted feature point on the endpoint detection curve is the 4th feature point F4, and the time interval between it and the historical feature point F1 is T1. When T1 is greater than T, the wear level of the polishing pad is considered to be in the middle to late stage. Figure 6In (c), no new feature points were extracted after the first time threshold T' at the distance from feature point F3, and the wear of the polishing pad was considered to be in the later stage.

[0051] It should be noted that, because the latest extracted feature points are constantly being updated, for example... Figure 6 As shown, if the time interval between the latest extracted feature point and a fixed historical feature point (e.g., feature point F1) is always used as the criterion, then a new second time threshold needs to be compared every time the feature point is updated. For example, when the latest feature point is feature point F2, the second time threshold is t1', and when the latest feature point is feature point F4, the second time threshold is t3'.

[0052] It should also be noted that, to simplify the implementation, this embodiment can select an adjacent feature point before the most recently extracted feature point as a historical feature point to determine the wear level of the polishing pad. In other words, this embodiment may not set a fixed historical feature point, but instead set a fixed second time threshold to represent the upper limit of the interval between any two feature points. If the interval between the latest feature point and the previous historical feature point is greater than the second time threshold, the wear level of the polishing pad is considered to have reached the middle to late stage.

[0053] In another example, such as Figure 7 As shown, Figure 7 In the diagram, (a) represents the endpoint detection curve corresponding to the previous target wafer. Figure 7 (b) in the figure represents the endpoint detection curve corresponding to the current target wafer. Figure 7 In each image, the position of the "□" represents the extracted feature point (feature point F1, F2, F3, F4). In the endpoint detection curve corresponding to the current target wafer, F4 represents the most recently extracted feature point, designated as the first feature point; in the endpoint detection curve corresponding to the previous target wafer, the last extracted feature point F4 is also designated as the first feature point; F1, F2, and F3 represent historical feature points, with feature point F1 designated as the second feature point. For example... Figure 7 In (b), the time interval between the first feature point and the second feature point on the endpoint detection curve corresponding to the current target wafer is the first time interval T3; as shown in (b). Figure 7 In (a), the time interval between the first feature point and the second feature point on the endpoint detection curve corresponding to the previous target wafer is the second time interval T3'. T3 is greater than T3', and the difference between the intervals of T3 and T3' is greater than the preset third time threshold. At this time, the wear level of the polishing pad is considered to be in the middle and late stages.

[0054] It should be noted that, with Figure 6Similarly, if the judgment is always based on the time interval between the most recently extracted feature point and a fixed historical feature point (e.g., feature point F1), then a new third time threshold needs to be compared every time the feature point is updated. For example, the most recently extracted feature point is taken as the first feature point, and a feature point preceding the first feature point is taken as the second feature point. Assuming the first feature point is the i-th feature point on the endpoint detection curve, then the second feature point is the (i-1)-th feature point on the endpoint detection curve. Each comparison requires calculating the time difference between the time interval between the i-th and (i-1)-th feature points in the current grinding process and the time interval between the i-th and (i-1)-th feature points in the previous grinding process, and then comparing this difference with the third time threshold corresponding to the i-th and (i-1)-th feature points.

[0055] Furthermore, when the endpoint detection curve is a first-type curve, any two adjacent feature points in the first-type curve constitute a sub-time period; The second time threshold includes at least one second sub-time threshold, each second sub-time threshold corresponds to a sub-time period, and the first preset condition specifically includes: the time interval between the latest extracted feature point and the historical feature point is greater than the second sub-time threshold corresponding to the sub-time period. Alternatively, the third time threshold includes at least one third sub-time threshold, each third sub-time threshold corresponding to a sub-time period, and the first preset condition specifically includes: the value of the first time interval being greater than the second time interval exceeds the third sub-time threshold corresponding to the sub-time period.

[0056] In one example, please see [link to example]. Figure 6 In (a) and (b), when the endpoint detection curve is a type I curve, the polishing pad grinds the same material layer of the target wafer. The time interval between feature points F1 and F2 is t1; the time interval between feature points F2 and F3 is t2; and the time interval between feature points F3 and F4 is t3. For example... Figure 6 In (a), assuming the polishing pad has not worn, each sub-time period corresponds to a second sub-time threshold (t1', t2', t3'). For example... Figure 6 In (b), when the polishing pad is worn, the time interval between the newly extracted feature point F4 and the historical feature point F3 is t3. Figure 6 The second sub-time threshold t3' corresponding to the sub-time period in (a) is compared. When the value of t3 is greater than the value of t3', the wear level of the polishing pad is considered to be in the middle to late stage. In the above description, the time period between two adjacent feature points is considered as a sub-time period. In other examples, a number of feature points can be spaced out as a sub-time period. For example, the time period between feature points F1 and F3 is considered as a sub-time period.

[0057] In another example, please see [link to example]. Figure 7 In (a) and (b), when the endpoint detection curve is a Type I curve, the polishing pad grinds the same material layer of the target wafer. In the Type I curve corresponding to the current target wafer: the time interval between feature points F1 and F2 is denoted as the first sub-time interval, with a corresponding time interval of t1; the time interval between feature points F2 and F3 is denoted as the second sub-time interval, with a corresponding time interval of t2; and the time interval between feature points F3 and F4 is denoted as the third sub-time interval, with a corresponding time interval of t3. In the Type I curve corresponding to the previous target wafer: the time interval between feature points F1 and F2 is denoted as the first sub-time interval, with a corresponding time interval of t11; the time interval between feature points F2 and F3 is denoted as the second sub-time interval, with a corresponding time interval of t22; and the time interval between feature points F3 and F4 is denoted as the third sub-time interval, with a corresponding time interval of t33.

[0058] The time interval error between the first sub-time period on the first type curve corresponding to the current target wafer and the first sub-time period on the first type curve corresponding to the previous target wafer is denoted as the third sub-time threshold d1. The time interval error between the second sub-time period on the first type curve corresponding to the current target wafer and the second sub-time period on the first type curve corresponding to the previous target wafer is denoted as the third sub-time threshold d2. The time interval error between the third sub-time period on the first type curve corresponding to the current target wafer and the third sub-time period on the first type curve corresponding to the previous target wafer is denoted as the third sub-time threshold d3.

[0059] F4 is the first feature point, and feature point F3 is designated as the second feature point. The first time interval between the first feature point F4 and the second feature point F3 on the first type curve corresponding to the current target wafer is t3. The second time interval between the first feature point F4 and the second feature point F3 on the first type curve corresponding to the previous target wafer is t33. When the value of t3 is greater than the value of t33, and the difference is greater than the value of d3, the wear level of the polishing pad is considered to be in the middle to late stage. In the aforementioned description, the time interval between two adjacent feature points is considered as a sub-time period. In other examples, a sub-time period can also be defined as several feature points, for example, the time interval between feature points F1 and F3 is considered as a sub-time period.

[0060] In some embodiments, if the extraction result is: the time interval between any two adjacent feature points in the endpoint detection curve is the first sub-time interval, and the time interval between any two adjacent feature points in the endpoint detection curve corresponding to the previous target wafer is the second sub-time interval; If the difference between the mean of all first sub-time intervals and the mean of all second sub-time intervals is greater than the fourth time threshold, the wear level of the polishing pad is determined to be in the middle to late stage.

[0061] It should be noted that the endpoint detection curve can be either a first-type curve or a second-type curve.

[0062] In one example, using the first type of curve, please see [link to example]. Figure 7 In (a) and (b), in the first type curve corresponding to the current target wafer: the time interval between feature points F1 and F2 is denoted as the first sub-time interval t1; the time interval between feature points F2 and F3 is denoted as the first sub-time interval t2; and the time interval between feature points F3 and F4 is denoted as the first sub-time interval t3. In the first type curve corresponding to the previous target wafer: the time interval between feature points F1 and F2 is denoted as the second sub-time interval t11; the time interval between feature points F2 and F3 is denoted as the second sub-time interval t22; and the time interval between feature points F3 and F4 is denoted as the second sub-time interval t33.

[0063] Obtain the average values ​​of t1, t2, and t3 in the first type curve corresponding to the current target wafer, and the average values ​​of t11, t22, and t33 in the first type curve corresponding to the previous target wafer. When the average values ​​of t1, t2, and t3 are greater than the average values ​​of t11, t22, and t33, and the difference is greater than the fourth time threshold, the wear level of the polishing pad is considered to be in the middle to late stage.

[0064] It should be noted that the first time threshold, the second time threshold, the third time threshold and the fourth time threshold in the embodiments of this application are preset values, which can be determined by combining actual experience or algorithm calculation to determine whether the wear degree of the polishing pad has reached the critical value of the middle and late stage. In other embodiments, they can be other values, and this embodiment does not limit them.

[0065] like Figure 8 As shown, it illustrates multiple Type I curves obtained by polishing the same material layer on multiple target wafers using a polishing pad. The positions of the "□" on the curves represent the extracted feature points.

[0066] Figure 8 In the first type of curve, (a) represents the first type of curve detected when the polishing pad is not worn. The interval between any adjacent feature points extracted on the first type of curve is consistent, and the polishing pad has a good lifespan.

[0067] After polishing multiple target wafers, the polishing pad produces the following results: Figure 8 The curve shown in (b) is... Figure 8(b) in the figure represents the first type of curve detected when the polishing pad is worn and the wear level reaches the mid-to-late and late stages, respectively. As can be seen from the dashed box in the figure, the time interval between the newly extracted feature point and a historical feature point on this first type of curve meets the first preset condition. At this time, the interval (frequency) of the signal converter capturing feature points is forced to increase, but the endpoint detection device itself is functioning normally, indicating that the polishing pad has undergone significant wear and entered the mid-to-late stage. The system detects that the polishing time is continuously increasing and issues an early warning accordingly. Although the polishing pad can still maintain basic polishing function, its lifespan has been largely consumed, and its performance has significantly deteriorated. The monitoring module of the endpoint detection device has identified that the time required to reach the same polishing endpoint is gradually increasing. This trend of decreased efficiency triggers a maintenance alarm, requiring attention and preparation for polishing pad replacement.

[0068] As can be seen from the bolded Type 1 curve in the figure, no new feature points were extracted after the first time threshold interval since the last feature point was extracted. This phenomenon indicates that the polishing pad is worn and the wear has reached a late stage, meaning the polishing pad's lifespan is nearing its end. Because the polishing pad's performance has deteriorated to the point that it can no longer reliably complete the process, the equipment triggers the highest-level alarm and stops grinding. At this point, the polishing pad needs to be replaced promptly.

[0069] Thus, in this embodiment, the lifespan of the polishing pad can be fed back by monitoring the polishing condition of the target wafer. The endpoint detection curve can be obtained by the endpoint detection device. A signal converter (or a graphic analyzer, etc.) can be added to the endpoint detection device. The signal converter can be used to capture feature points from the endpoint detection curve. Combined with the data captured by the endpoint detection device, the lifespan of the polishing pad can be analyzed. The final lifespan of the polishing pad can be understood in a timely manner, thereby accurately controlling the lifespan of the polishing pad and avoiding the difficulty in judging the wear degree of the polishing pad due to different manufacturing processes.

[0070] like Figure 9 As shown, this diagram illustrates multiple Type II curves obtained by polishing different material layers on multiple target wafers using a polishing pad. The "□" on the curve indicates the extracted feature point. When polishing target wafers with stacked materials having a stop layer, different material layers cause significant steps in reflected light intensity. By continuously monitoring and analyzing the time interval trend between light intensity change points, the wear state and remaining lifetime of the polishing pad can be determined.

[0071] Figure 9 In the diagram (a), multiple second-type curves are detected when the polishing pad is not worn. The intervals between adjacent feature points extracted on the second-type curves are consistent, indicating that the polishing pad has a good lifespan.

[0072] After polishing multiple target wafers, the polishing pad produces the following results: Figure 9The multiple curves shown in (b) are as follows: Figure 9 (b) in the figure represents the second type of curve detected when the polishing pad is worn and the wear level reaches the mid-to-late and late stages, respectively. As can be seen from the dashed box in the figure, the time interval between the newly extracted feature point and a historical feature point on this second type of curve meets the first preset condition. At this time, the interval (frequency) of the signal converter capturing feature points is forced to increase, but the endpoint detection device itself is functioning normally, indicating that the polishing pad has undergone significant wear and entered the mid-to-late stage. The system detects that the polishing time is continuously increasing and issues an early warning accordingly. Although the polishing pad can still maintain basic polishing function, its lifespan has been largely consumed, and its performance has significantly deteriorated. The monitoring module of the endpoint detection device has identified that the time required to reach the same polishing endpoint is gradually increasing. This trend of decreased efficiency triggers a maintenance alarm, requiring attention and preparation for polishing pad replacement.

[0073] As can be seen from the bolded second-type curve in the figure, no new feature points were extracted after the first time threshold interval since the last feature point was extracted. This phenomenon indicates that the polishing pad is worn and has reached a late stage of wear, meaning the polishing pad's lifespan is nearing its end. Because the polishing pad's performance has deteriorated to the point that it can no longer reliably complete the process, the equipment triggers the highest-level alarm and stops grinding. At this point, the polishing pad needs to be replaced promptly.

[0074] It should be noted that the time interval during which the light intensity drops significantly on the second type of curve represents the time interval during which the polishing pad moves from one material layer of the target wafer to the stop layer of the target wafer.

[0075] In this embodiment, the polishing pad's lifespan is fed back by monitoring the grinding condition of the target wafer. This allows for timely understanding of the polishing pad's final lifespan, thus enabling precise control of the polishing pad's lifespan and avoiding the difficulty in judging the degree of polishing pad wear due to different manufacturing processes.

[0076] In summary, this application provides a method for detecting the wear of a polishing pad. The method first obtains the correspondence between polishing time and light intensity parameters during the chemical mechanical polishing process of the polishing pad on the target wafer, resulting in an endpoint detection curve. Then, feature points on the endpoint detection curve are extracted, and the degree of wear of the polishing pad is determined based on the extraction results. If the time interval between the newly extracted feature point and a historical feature point meets a first preset condition, the wear degree of the polishing pad is determined to be in the middle to late stage. If no new feature point is extracted after a first time threshold interval from the last extracted feature point, the wear degree of the polishing pad is determined to be in the late stage. When the wear degree of the polishing pad is in the middle to late stage, the system issues an alarm; when the wear degree of the polishing pad is in the late stage, the polishing pad stops polishing.

[0077] In this way, by observing the relationship between grinding time and light intensity parameters and the characteristic points on the endpoint detection curve, the real-time wear of the polishing pad can be accurately monitored, allowing it to be replaced at the optimal time and avoiding misjudgment of wear caused by differences in different processes.

[0078] In another embodiment of this application, such as Figure 10 As shown, it illustrates a schematic diagram of the structural composition of a polishing pad wear detection device provided in an embodiment of this application. Figure 10 As shown, the wear detection device 20 for the polishing pad may include: The acquisition unit 201 is configured to acquire the endpoint detection curve; the endpoint detection curve is used to represent the relationship between the polishing time and the light intensity parameter during the chemical mechanical polishing of the target wafer using a polishing pad. Extraction unit 202 is configured to extract feature points from the endpoint detection curve to obtain extraction results; The detection unit 203 is configured to determine the degree of wear of the polishing pad based on the extraction results.

[0079] In some embodiments, the detection unit 203 is specifically configured to: if the extraction result is that the time interval between the latest extracted feature point and a historical feature point meets the first preset condition, determine that the wear level of the polishing pad is in the middle or late stage; If the extraction result is: no new feature points are extracted after the first time threshold interval since the last feature point was extracted, the wear level of the polishing pad is determined to be in the later stage.

[0080] In some embodiments, the detection unit 203 may be specifically configured such that: if the extraction result is: the time interval between any two adjacent feature points in the endpoint detection curve is the first sub-time interval, and the time interval between any two adjacent feature points in the endpoint detection curve corresponding to the previous target wafer is the second sub-time interval; If the difference between the mean of all first sub-time intervals and the mean of all second sub-time intervals is greater than the fourth time threshold, the wear level of the polishing pad is determined to be in the middle to late stage.

[0081] In some embodiments, such as Figure 11 As shown, it illustrates a schematic diagram of the structural composition of another polishing pad wear detection device provided in an embodiment of this application. Figure 11 As shown, the acquisition unit 201 can specifically be the endpoint detection device 2011; the extraction unit 202 can specifically be the signal converter 2021.

[0082] It should be noted that the endpoint detection curve acquired by the endpoint detection device is a waveform containing noise. The signal converter 2021 needs to extract quantifiable indicators with clear physical meaning from it. Therefore, a signal converter 2021 is added to the endpoint detection device 2011. The signal converter 2021 acquires the feature points of the endpoint detection curve and the time interval between these feature points and historical feature points. Alternatively, the extraction unit 202 can also be an image analyzer or other device; no specific limitation is made here.

[0083] It should be noted that the polishing pad wear detection device 20 provided in this application embodiment is used to implement the polishing pad wear detection method in the aforementioned embodiment. For details not disclosed in this application embodiment, please refer to the description of the aforementioned embodiment for understanding, and will not be repeated here.

[0084] Understandably, in this embodiment, a "unit" can be a portion of a circuit, a portion of a processor, a portion of a program or software, etc., and can also be a module or a non-modular component. Furthermore, the components in this embodiment can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional module.

[0085] If the integrated unit is implemented as a software functional module and not sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the method described in this embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0086] Therefore, this embodiment provides a computer-readable storage medium storing a computer program that, when executed by at least one processor, implements the steps of the polishing pad wear detection method of any of the foregoing embodiments.

[0087] Based on the aforementioned polishing pad wear detection device 20 and computer storage medium, see [link to relevant documentation]. Figure 12This illustrates a schematic diagram of the structural composition of an electronic device provided in an embodiment of this application. For example... Figure 12 As shown, the electronic device 30 may include a communication interface 301, a memory 302, and a processor 303; the various components are coupled together via a bus system 304. It is understood that the bus system 304 is used to implement communication between these components. In addition to a data bus, the bus system 304 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 12 All buses are labeled as bus system 304. Among them, communication interface 301 is used for receiving and sending signals during the process of sending and receiving information with other external network elements.

[0088] Memory 302 is used to store computer programs that can run on processor 303; The processor 303 is configured to execute the steps of the aforementioned polishing pad wear detection method when running the computer program.

[0089] It is understood that the memory 302 in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The memory 302 of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0090] The processor 303 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 303 or by instructions in software form. The processor 303 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory 302, and the processor 303 reads the information in memory 302 and, in conjunction with its hardware, completes the steps of the above method.

[0091] It is understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions described herein, or combinations thereof.

[0092] For software implementation, the techniques described herein can be achieved through modules (e.g., procedures, functions, etc.) that perform the functions described herein. The software code can be stored in memory and executed by a processor. The memory can be implemented within the processor or externally.

[0093] In another embodiment of this application, another electronic device 30 is also provided, which includes at least the wear detection device 20 for any of the polishing pads in the foregoing embodiments.

[0094] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application.

[0095] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0096] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0097] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0098] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0099] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0100] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. A method for detecting the wear of a polishing pad, characterized in that, The method includes: Obtain the endpoint detection curve; the endpoint detection curve is used to represent the relationship between polishing time and light intensity parameters during the chemical mechanical polishing of the target wafer using the polishing pad; Feature points are extracted from the endpoint detection curve to obtain the extraction results; Based on the extraction results, the degree of wear of the polishing pad is determined.

2. The method according to claim 1, characterized in that, Determining the wear level of the polishing pad based on the extraction results includes: If the extraction result is: the time interval between the latest extracted feature point and a historical feature point meets the first preset condition, the wear level of the polishing pad is determined to be in the middle and late stages; If the extraction result is: no new feature point is extracted after a first time threshold interval from the last extraction of the feature point, the wear degree of the polishing pad is determined to be in the later stage.

3. The method according to claim 2, characterized in that, The first preset condition includes: the time interval between the newly extracted feature point and the historical feature point is greater than a second time threshold; the second time threshold is the upper limit of the time interval between two feature points when the polishing pad has not worn out; Alternatively, the newly extracted feature point and the historical feature point are respectively the first feature point and the second feature point in the endpoint detection curve, the time interval between the first feature point and the second feature point in the endpoint detection curve is the first time interval, the time interval between the first feature point and the second feature point in the endpoint detection curve corresponding to the previous target wafer is the second time interval, and the first preset condition includes: the value of the first time interval being greater than the second time interval exceeds the third time threshold.

4. The method according to claim 2 or 3, characterized in that, The historical feature points are the adjacent feature points before the most recently extracted feature point.

5. The method according to claim 3, characterized in that, The endpoint detection curve is either a first type curve or a second type curve. The first type curve is the curve obtained during the grinding of the same material layer of the target wafer, and the second type curve is the curve obtained during the grinding of different material layers of the wafer. In the first type of curve, the feature point is the point corresponding to the peak or trough; In the second type of curve, the feature point is an inflection point.

6. The method according to claim 5, characterized in that, When the endpoint detection curve is the first type of curve, any two adjacent feature points in the first type of curve constitute a sub-time period. The second time threshold includes at least one second sub-time threshold, each second sub-time threshold corresponds to a sub-time period, and the first preset condition specifically includes: the time interval between the latest extracted feature point and the historical feature point is greater than the second sub-time threshold corresponding to the sub-time period; Alternatively, the third time threshold includes at least one third sub-time threshold, each of the third sub-time thresholds corresponding to a sub-time period, and the first preset condition specifically includes: the value of the first time interval being greater than the second time interval exceeds the third sub-time threshold corresponding to the sub-time period.

7. The method according to claim 2, characterized in that, The step of determining the wear level of the polishing pad based on the extraction results further includes: The extraction result is as follows: the time interval between any two adjacent feature points in the endpoint detection curve is the first sub-time interval, and the time interval between any two adjacent feature points in the endpoint detection curve corresponding to the previous target wafer is the second sub-time interval; If the difference between the mean of all first sub-time intervals and the mean of all second sub-time intervals is greater than the fourth time threshold, the wear level of the polishing pad is determined to be in the middle to late stage.

8. The method according to claim 2, characterized in that, When the wear level of the polishing pad is in the middle or late stage, the method further includes: issuing an alarm; If the polishing pad is in a later stage of wear, the method further includes stopping the polishing process.

9. A device for detecting the wear of a polishing pad, characterized in that, include: The acquisition unit is configured to acquire the endpoint detection curve; The endpoint detection curve is used to represent the relationship between polishing time and light intensity parameters during the chemical mechanical polishing of the target wafer using the polishing pad. The extraction unit is configured to extract feature points from the endpoint detection curve to obtain the extraction result. The detection unit is configured to determine the degree of wear of the polishing pad based on the extraction results.

10. The loss detection device according to claim 9, characterized in that, The acquisition unit is an endpoint detection device; the extraction unit is a signal converter.

11. An electronic device, characterized in that, Including memory and processor; The memory is used to store computer programs that can run on the processor; The processor is configured to, when running the computer program, execute the steps of the wear detection method for the polishing pad as described in any one of claims 1 to 8.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by at least one processor, implements the steps of the wear detection method for the polishing pad as described in any one of claims 1 to 8.

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