Wafer polishing method and equipment, data processing equipment, program, storage medium

Abstract

This invention relates to a wafer polishing method and apparatus, data processing equipment, program, and storage medium. The polishing method includes: loading a wafer to be polished; reading in a first polishing formula and performing primary polishing on the wafer according to the formula; detecting the wafer parameters of all zones of the wafer, determining whether the wafer parameters of all zones meet the standards, and if so, unloading the wafer; if not, obtaining a second polishing formula based on the wafer parameters using a dynamic adjustment model, performing secondary polishing on the non-compliant zones of the wafer based on the second polishing formula, and then returning to re-detect the wafer parameters of the wafer zones until it is determined that the wafer parameters of all zones meet the standards, and unloading the polished wafer. This invention enables automatic multi-zone triggering and time-pressure automatic joint adjustment rework function during wafer polishing, avoiding repeated processing of the entire wafer, and reducing material consumption and costs.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing technology for semiconductor wafers; more specifically, this invention relates to wafer polishing methods and equipment, data processing equipment, programs, and storage media. Background Technology

[0002] Chemical mechanical polishing (CMP) is the preferred technique for planarizing semiconductor wafer surfaces. However, in CMP, over-polishing can damage material properties and affect device performance, while under-polishing may require additional processing steps, increasing costs.

[0003] Currently, in the application of chemical mechanical polishing (CMP), endpoint stopping parameters need to be preset. Once the polishing process reaches the preset endpoint stopping parameters, the polishing operation is stopped, resulting in the processed wafer. However, this method of determining the polishing endpoint based on endpoint stopping parameters cannot accurately detect whether the surface morphology of the polished wafer meets the standard requirements. This leads to a large deviation between the wafer surface flatness and the actual flatness, and it is not applicable to wafers with multilayer film structures. Summary of the Invention

[0004] In view of the above, the present invention provides a wafer polishing method and apparatus, a data processing apparatus, a program, and a storage medium, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] To achieve the aforementioned objective, a first aspect of the present invention provides a wafer chemical mechanical polishing method, wherein the polishing method includes:

[0006] Step 1: Load the wafer to be polished;

[0007] Step II: Read in the first polishing formula, perform primary polishing on the wafer according to the first polishing formula, and stop the primary polishing by endpoint detection technology;

[0008] Step III: Detect the wafer parameters of all partitions of the wafer and determine whether the wafer parameters of all partitions of the wafer meet the standard. If the wafer parameters of all partitions meet the standard, proceed to step V. If the wafer parameters of all or some partitions do not meet the standard, proceed to step IV.

[0009] Step IV: Obtain a second polishing formula based on the wafer parameters of all the partitions by dynamically adjusting the model, perform secondary polishing on the non-compliant partitions of the wafer based on the second polishing formula, and return to Step III;

[0010] Step V: Unload the polished wafer and return to Step I.

[0011] In the polishing method described above, optionally, the parameters of the first polishing formulation and the second polishing formulation include polishing time, holding ring pressure, and polishing pressure on each partition of the wafer.

[0012] In the polishing method described above, optionally, the endpoint detection technology includes an eddy current endpoint detection method and / or an optical endpoint detection method and / or a motor torque endpoint detection method. In the eddy current endpoint detection method, the measurement of the film thickness of the wafer adopts the eddy current detection principle, and in the optical endpoint detection method, the measurement of the film thickness of the wafer adopts the optical detection principle.

[0013] In the polishing method described above, optionally, the wafer parameters include the film thickness of the wafer.

[0014] In the polishing method described above, optionally, the measurement principle of the film thickness of the partition of the wafer includes the eddy current detection principle and / or the optical detection principle.

[0015] In the polishing method described above, optionally, the optical detection principle uses light of a certain wavelength to irradiate the wafer surface and obtains the film thickness of the wafer by analyzing the reflected wavelength. The lower limit of the goodness of fit is set to 0.98. The goodness of fit is the degree of fit between the actual measured reflection wavelength curve and the wavelength curve calibrated by the machine. If the goodness of fit is lower than the lower limit, the measurement is repeated or a new measurement point is selected.

[0016] In the polishing method described above, optionally, at least one measurement point is provided at each of the partitions of the wafer.

[0017] In the polishing method described above, optionally, the dynamic adjustment model includes a calculation model for the polishing time, wherein the calculation model for the polishing time is:

[0018]

[0019] Where T is the polishing time, PreZ[i]PointMax is the maximum value of the wafer parameters in the Z[i] partition, i = 1, 2, ..., n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions of the wafer, and RR is the removal rate.

[0020] In the polishing method described above, optionally, the dynamic adjustment model includes a calculation model for the polishing pressure of each partition of the wafer, wherein the calculation model for the polishing pressure is:

[0021]

[0022] Where P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum value of the wafer parameters of the Z[i] partition, i = 1, 2, ..., n, Target is the target wafer parameter value, n is the number of partitions of the wafer, 5 ≤ n ≤ 12, k is the empirical coefficient, and Thk_Offset_Spec is the target control line.

[0023] In the polishing method described above, optionally, the first polishing formula is a pre-set standard formula, and the second polishing formula is generated and adjusted in real time by the dynamic adjustment module based on the detection results of the wafer parameters.

[0024] To achieve the aforementioned objective, a second aspect of the present invention provides a wafer polishing apparatus, wherein the wafer polishing apparatus is used to perform the polishing method as described in any one of the first aspects above, the wafer polishing apparatus comprising:

[0025] A polishing module performs primary polishing on a wafer according to a first polishing formula sent by a dynamic adjustment module, or secondary polishing on a wafer according to a second polishing formula. The polishing module includes a polishing disc, a polishing head, and a liquid supply device. The polishing disc is covered with a polishing pad for polishing the wafer. The polishing head is loaded with the wafer. The wafer is pressed against the polishing pad on the polishing disc by the polishing disc. The liquid supply device sprays polishing liquid onto the surface of the polishing pad. Under the action of the polishing liquid, the wafer is polished by friction between the polishing disc and the polishing pad due to the relative movement of the polishing disc and the polishing pad.

[0026] The endpoint detection module performs wafer parameter detection on the wafer and stops polishing using endpoint detection technology. The endpoint detection module sends the detection results of the wafer parameters to the dynamic adjustment module.

[0027] A dynamic adjustment module receives the detection results of the wafer parameters sent by the endpoint detection module, generates a second polishing formula, and sends a first polishing formula or a second polishing formula to the polishing module. To achieve the foregoing objective, a third aspect of the present invention provides a data processing apparatus, wherein the data processing apparatus includes:

[0028] The memory is used to store computer-executable instructions or computer programs;

[0029] A processor, when executing computer-executable instructions or computer programs stored in the memory, implements the polishing method as described in any one of the preceding first aspects.

[0030] To achieve the foregoing objectives, a fourth aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions or a computer program that, when executed by a processor, implement the polishing method as described in any one of the first aspects above.

[0031] To achieve the aforementioned objective, a fifth aspect of the present invention provides a computer program, wherein the computer program includes computer-executable instructions or a computer program, which, when executed by a processor, implement the polishing method as described in any one of the first aspects above.

[0032] This invention performs primary polishing of wafers based on a first polishing formula, uses endpoint detection technology to stop the polishing process, and then performs secondary polishing by detecting wafer parameters in different zones and dynamically updating the second polishing formula. This achieves a multi-zone automatic triggering and time-pressure automatic joint adjustment rework function, improving polishing efficiency, reducing rework difficulty, and enhancing product quality and production efficiency. This invention can adjust pressure in real time by zone during wafer polishing, and has a zone-based automatic rework function, avoiding repeated processing of the entire wafer and reducing material consumption and costs.

[0033] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0035] Figure 1 A flowchart illustrating one embodiment of the wafer polishing method according to the present invention is shown schematically;

[0036] Figure 2 This is a schematic diagram of the polishing process of one embodiment of the wafer polishing method of the present invention;

[0037] Figure 3 A schematic block diagram illustrating one embodiment of a wafer polishing apparatus according to the present invention is shown.

[0038] Figure 4A schematic block diagram illustrating an embodiment of a data processing apparatus according to the present invention is shown.

[0039] Figure Labels :

[0040] 10 - First film layer of wafer; 20 - Second film layer of wafer; 30 - Silicon substrate of wafer. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art should fall within the protection scope of the present invention.

[0042] It should be understood that, unless otherwise specified or logically contradictory, the steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0043] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Relevant definitions of other terms will be given in the description below.

[0044] Furthermore, in this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the order of the indicated technical features.

[0045] Figure 1 A flowchart illustrating an embodiment of the wafer polishing method according to the present invention is shown schematically. As can be seen from the figure, the method may include steps I through V.

[0046] In step I, the wafer to be polished is loaded.

[0047] More specifically, in step I, the wafer to be polished needs to be loaded onto the polishing head of the wafer polishing equipment for subsequent processing. For example, the wafer polishing equipment may include a polishing pad, a polishing head (or a support head), and a liquid supply device. The polishing pad may be covered with a polishing pad for polishing the wafer. The wafer is loaded onto the polishing head via a conductive rubber gas film. The polishing head presses the wafer against the polishing pad on the polishing pad, and the liquid supply device sprays polishing fluid onto the surface of the polishing pad. Under the chemical action of the polishing fluid, the relative movement between the polishing head and the polishing pad causes friction between the wafer and the polishing pad, thus achieving polishing. After loading the wafer, proceed to step II.

[0048] In step II, the first polishing formula is read in, and the wafer is subjected to primary polishing according to the first polishing formula. The primary polishing is stopped by endpoint detection technology (EPD).

[0049] In conjunction with step I, in an optional embodiment, chemical mechanical polishing (CMP) is used to perform primary polishing on the wafer. By applying pressure to the polishing head, the wafer is brought into contact with and rotated on the polishing pad. The polishing is stopped by endpoint detection technology, thereby achieving preliminary planarization of the wafer surface.

[0050] In an optional embodiment, the parameters of the polishing formulation may include polishing time, holding ring pressure, and pressure on each partition of the wafer.

[0051] The pressure applied to each partition of the wafer can be achieved using a conductive rubber gas film in the polishing head. A conductive rubber gas film can be provided on the wafer holding surface of the polishing head, and annular partitioned gas chambers can be formed within this film. The pressure in each partition of the wafer can be adjusted by controlling the amount of gas filling these annular partitioned gas chambers. The wafer can be mounted on the polishing head using the conductive rubber gas film.

[0052] It is understood that polishing time refers to the time spent polishing a wafer, from the start of polishing to the end. During polishing, too short a polishing time will result in insufficient polishing, while too long a polishing time may lead to over-polishing, causing damage to the wafer surface. During wafer polishing, the wafer is fixed to the polishing head, and the retaining ring on the polishing head ensures the wafer's stable position during polishing. Correct and effective retaining ring pressure ensures effective polishing of the wafer surface. Too little retaining ring pressure may cause the wafer to slide or shift during polishing, affecting the uniformity and accuracy of polishing. Too much retaining ring pressure may lead to uneven stress distribution on the wafer surface, affecting the wafer's flatness and polishing quality. Polishing pressure is a key factor affecting wafer surface roughness. Too much polishing pressure will lead to over-polishing, while too little polishing pressure will lead to insufficient polishing. By precisely controlling the polishing pressure of each zone, more refined polishing control can be achieved to obtain the required flatness, smoothness, and rework effect.

[0053] The EPD technology here can be implemented through software control. This software can integrate eddy current endpoint detection, optical endpoint detection, and / or motor torque endpoint detection functions to meet the needs of various processes. During the wafer polishing process, endpoint detection technology can monitor wafer parameters on the wafer surface in real time, allowing the polishing process to be stopped in a timely manner when the predetermined flatness and thickness are reached. Endpoint detection technology can avoid wafer defects caused by over- or under-polishing and is key to achieving global wafer planarization.

[0054] As mentioned above, in optional embodiments, wafer endpoint detection technology may include eddy current endpoint detection methods and / or optical endpoint detection methods and / or motor torque endpoint detection methods.

[0055] Eddy current endpoint detection is a method based on the principle of eddy current detection to measure the thickness of the metal layer on a wafer surface. When a metal conductor is placed in a changing magnetic field, or moves within a magnetic field cutting magnetic lines of force, an induced current in the form of eddies will be generated within the conductor; this current is called an eddy current. The eddy current endpoint detection method uses an eddy current sensor to monitor the changes in eddy currents induced by the metal layer on the wafer surface, thereby achieving accurate measurement of the metal layer thickness.

[0056] The optical endpoint detection method measures the film thickness on a wafer surface using optical detection principles. This principle involves irradiating the wafer surface with light of a specific wavelength and analyzing the reflected wavelength to determine the film thickness. In optional embodiments, a goodness-of-fit parameter can be set, which is the degree of fit between the measured reflection wavelength curve and the wavelength curve calibrated by the instrument. In some embodiments, a lower limit for the goodness-of-fit can be set to 0.98. Measurements with a goodness-of-fit below this limit are considered invalid, and the measurement is repeated or a new measurement point is selected until the goodness-of-fit is not lower than the lower limit.

[0057] The principle of the motor torque endpoint detection method is to detect changes in motor torque during the polishing process to stop the wafer polishing process. By installing a torque sensor on the motor shaft of the polishing head, the changes in motor torque readings are analyzed to determine whether the polishing process is nearing its endpoint. In this method, at the beginning of polishing, the film thickness on the wafer surface is relatively thick, and the friction between the polishing disk and the wafer is high. At this time, the motor needs to output a large torque to maintain the rotation of the polishing disk. As polishing progresses, the film is gradually removed, the friction decreases, and the motor torque also decreases accordingly. When the film thickness reaches the expected value, the friction reaches the expected value, and the motor torque reaches a set threshold, at which point the polishing endpoint can be considered reached. Furthermore, different film layers on the wafer have different coefficients of friction against the polishing disk during polishing. As the polishing head passes through different film layers on the wafer, the motor torque changes. By detecting these changes in real time, the endpoint of the polishing process can be accurately determined. The motor torque endpoint detection method ensures the accuracy and efficiency of the multilayer wafer polishing process by monitoring torque changes in real time.

[0058] In some embodiments, two or more of the aforementioned methods can be combined for polishing endpoint detection, and cross-validation can be used to ensure that the wafer surface film thickness reaches the expected value. In optional embodiments, at least two data points can be detected, which may include two or more of eddy current data, optical data, and motor torque data, and compared with the corresponding film thickness data to determine the remaining thickness of the polished wafer. When the remaining thickness of the polished wafer is detected to have reached the desired film thickness, the wafer polishing equipment stops polishing at the polishing endpoint. This automatic polishing stopping method can avoid the problem of wafer damage or wafer surface quality degradation caused by over-polishing, improve the accuracy of wafer polishing, reduce material waste, and improve overall efficiency.

[0059] EPD stop endpoint detection has very high requirements for the stability of wafer morphology. If the wafer morphology is not stable, there may be insufficient or excessive grinding removal in different radius partitions, forming ring-shaped residues. Especially for precision nanoscale processes, the consistency requirements for the grinding rate corresponding to each radius partition are even higher, making it difficult to achieve real-time pressure adjustment of partitions.

[0060] In this context, in order to repolish the wafer to adjust the film layer in each area of ​​the wafer to meet the process requirements, a method has been developed and extended to perform partition rework by dynamically adjusting the model partitioning operation, thereby lowering the usage threshold and meeting the CMP process design of composite film layers.

[0061] In step III, the wafer parameters of all partitions of the wafer are detected to determine whether the wafer parameters of all partitions of the wafer meet the standards. If the wafer parameters of all partitions meet the standards, proceed to step V; if the wafer parameters of all or some partitions do not meet the standards, proceed to step IV.

[0062] In optional embodiments, wafer parameters may include film thickness and / or other parameters, such as surface flatness. In optional embodiments, a surface profilometer can be used to measure the surface flatness and profile of the wafer after polishing. The film thickness here refers to the film thickness after CMP primary polishing.

[0063] In actual processing, wafer surfaces may exhibit varying thicknesses, with differences in film thickness across different areas. After initial polishing, some areas may have excessive or insufficient material removal, resulting in an uneven wafer surface that fails to achieve the desired wafer morphology. By performing zoned inspection of the wafer, more precise polishing control can be provided, ensuring polishing uniformity across different areas and achieving higher polishing accuracy.

[0064] In different embodiments, the method of wafer partitioning is not limited, and a suitable wafer partitioning method can be selected according to different process steps or wafer types. In the current embodiment, the wafer can be divided into several annular partitions according to different radius ranges. Since the wafer polishing stop does not consider the situation of each partition in the primary polishing step, it is possible to re-inspect and rework each partition to improve product quality.

[0065] The wafer partitioning parameter here can be the wafer thickness. When measuring the film thickness of each partition of the wafer, the measurement principle can include the aforementioned eddy current detection principle and / or optical detection principle. It is important to note that, as mentioned above, the motor torque measurement principle does not directly involve measuring the wafer film thickness, but rather determines whether polishing should stop based on changes in motor torque during polishing. Therefore, compared to the motor torque measurement principle, the eddy current detection principle and / or optical detection principle are more suitable for measuring the film thickness of wafer partitions. In the eddy current detection principle, the conductivity of different regions can be used to distinguish different wafer partitions, and the film thickness of each partition can be measured. In the optical detection principle, optical detection technology can achieve wafer partition detection by scanning different regions and analyzing the reflection spectrum.

[0066] In optional embodiments, upper specification limits, upper control limits, lower control limits, and lower specification limits can be set. The upper and lower specification limits can be the maximum and minimum acceptable values ​​for the wafer's film thickness. If the measured film thickness exceeds the upper specification limit or is less than the lower specification limit, the wafer can be deemed unqualified. If the film thickness is within the upper and lower control limits, the wafer polishing process can be considered under control. If it exceeds the upper and lower control limits, it indicates that the wafer polishing process may be abnormal or mutated, requiring investigation by the operator.

[0067] According to some embodiments, after the wafer undergoes primary polishing using the first polishing formula, the wafer needs to be divided into zones for film thickness detection. If the film thickness in a region does not meet the set expected film thickness, that region needs to be reworked for secondary polishing, while areas that meet the standard do not require rework. This avoids over-polishing or insufficient polishing in some areas of the wafer surface. Furthermore, due to rotation, the center and edges of the wafer may have different removal rates; therefore, real-time adjustment of polishing pressure by region makes it easier to detect and correct deviations promptly, ensuring wafer quality. In optional embodiments, when determining whether the film thickness of a region of the wafer meets the standard, a target thickness can be set. When the measured film thickness reaches the target thickness, the film thickness of that region of the wafer is considered to be within the standard range.

[0068] In step III, as previously described, the measurement principle for the film thickness of the wafer partitions can include eddy current detection and / or optical detection principles. Since the insufficiently polished annular regions remain in the film layer of the same material (e.g., silicon dioxide) after the primary polishing, the film thickness measurement at this time is for the film thickness of the partitions to be reworked.

[0069] The wafer parameters of each partition of the wafer are statistically analyzed to determine whether the wafer parameters of all partitions of the wafer meet the standards. In an optional embodiment, the number of partitions can be 5 ≤ n ≤ 12. To achieve optimal processing efficiency and quality, the number of partitions can be selected as 7. Other numbers of partitions can also be used in different embodiments.

[0070] If the wafer parameters of all partitions of the wafer meet the standards, the wafer polishing process can be considered to meet the expected process standards. The process then proceeds to unloading the polished wafer and loading the next wafer to be polished, i.e., step V. If the wafer parameters of all or some partitions of the wafer do not meet the standards, the non-compliant partitions need to be reworked and polished one or more times to meet the expected process standards, i.e., step IV. Steps IV and V are described below.

[0071] In step IV, a second polishing formula is obtained by dynamically adjusting the model based on the wafer parameters of the wafer partition. Based on the second polishing formula, the substandard partitions of the wafer are polished in a secondary manner, and then the process returns to step III.

[0072] If the wafer parameters are found to be substandard in step III, proceed to step IV. After the wafer has been inspected in sections, read in the second polishing formula and automatically rework the wafer in sections, that is, perform secondary polishing on the wafer.

[0073] The dynamic adjustment model is applied to processes such as stop-in-film treatment, dynamically adjusting time and pressure to meet multi-process throughput requirements. This invention improves upon the dynamic adjustment model, developing and extending its application for zoned rework. According to a specific embodiment of the invention, when EPD processes result in insufficient or excessive grinding removal in certain zones, the combined application of this dynamic adjustment model enables automatic zoned rework by adjusting the pressure of each zone and balancing pressure and time.

[0074] The dynamic adjustment model can receive wafer parameter detection results and analyze the collected data to calculate a second polishing formula. In optional embodiments, the dynamic adjustment model can have built-in optimization algorithms, such as machine learning models. The model can also record all historical data and generate the optimal second polishing formula based on historical data and real-time feedback to achieve the best polishing effect. Through the dynamic adjustment mechanism provided by the dynamic model, the wafer polishing system can adapt to different wafer characteristics and polishing requirements, ensuring high-quality polishing results.

[0075] In optional embodiments, the parameters of the first and second polishing formulations may include polishing time, holding ring pressure, and pressure on each partition of the wafer. In optional embodiments, the first polishing formulation can be a pre-set standard formulation based on historical experience and process requirements to ensure that the primary polishing of the wafer proceeds as expected, achieving the desired material removal rate and surface quality. However, due to the complexity of the wafer polishing process, the polishing effect may differ from expectations. Therefore, a dynamic adjustment module is needed to generate and adjust the second polishing formulation in real time based on the detection results of the wafer parameters. The holding ring pressure can be selected from standard formulations or other commonly used formulation pressures to ensure that the wafer does not scratch. Through dynamic adjustment, the wafer polishing process can be more flexibly adapted to different wafer characteristics and process requirements, thereby improving the wafer polishing quality.

[0076] In an optional embodiment, the dynamic model includes a calculation model for polishing time, that is, the formula for calculating the polishing time in the parameters of the second polishing formula can be:

[0077]

[0078] Where T is the polishing time, PreZ[i]PointMax is the maximum value of the wafer parameters in partition Z[i], i = 1, 2, ..., n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions on the wafer, and RR is the removal rate. The number of partitions can be, for example, 5, 7, 9, 11, or other suitable numbers. The Max function here is defined as Max(a,b,c,d,e) = the largest parameter among a, b, c, d, and e.

[0079] To better understand, the formula for calculating polishing time can be expressed as the ratio of the maximum amount removed to the maximum removal rate across all areas of the wafer. Here, the maximum amount removed can correspond to the area with the highest removal amount or the point with the highest required removal amount, and the removal rate (RR) is the rate at which material is removed during the polishing process.

[0080] The dynamic adjustment model can include a calculation model for the polishing pressure of each partition of the wafer. That is, the calculation formula for the polishing pressure of each partition of the wafer in the parameters of the second polishing recipe can be:

[0081]

[0082] Where P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum value of the wafer parameters of partition Z[i], i = 1, 2, ..., n, Target is the target wafer parameter value, n is the number of partitions of the wafer, and the value of n is, for example, 5, 7, 9, 11 or other suitable values, k is an empirical coefficient, and Thk_Offset_Spec is the target control line. Here, the If function is defined as If(((ad)>0),b,c), where ad>0 is true and the result is b, and ad>0 is false and the result is c; the Step function is defined as Step(a,b,c) (ab>c is 1, ab≤c is 0); the Max function is defined as Max(a,b,c,d,e) = the largest parameter among a,b,c,d,e. That is, the pressure on each partition = the default pressure of the current partition * (1 - whether (1 - maximum removal amount required for the current partition / maximum removal amount required for all partitions > 0) is true, if true, the result is 1, if false, the result is 0) * empirical coefficient * maximum removal amount required for the current partition / maximum removal amount required for all partitions) * whether the maximum removal amount required for the current partition has reached the rework control line, if it has, the result is 1, if not, the result is 0). This formula comprehensively reflects the default pressure of each partition, the empirical coefficient, the current partition removal ratio, and whether the partition has reached the rework control line. This formula can specifically correspond to the following situations:

[0083] (1) The current region is the region with the largest amount of removal required. If the function is 0 and the Step function is 1, the final result is the pressure of the current region. Then the maximum amount of removal required for the current partition is the maximum amount of removal required for all partitions. P[i] = Z[i]_Press;

[0084] (2) If the current area is not the area requiring the largest removal amount, the If function is 1, the Step function is 1, and the final result is the pressure of the current area * (1 - k * the removal amount required by the current area / the maximum removal amount required).

[0085]

[0086] (3) The maximum amount of removal required in the current region is <0, the Step function is 0, the final result is 0, and P[i] = 0.

[0087] By using the partitioned detection of wafer parameters and the dynamic updating of the second polishing formula in this invention, and then performing secondary polishing, rework with automatic time-pressure joint adjustment in multiple zones is achieved, which improves polishing efficiency, reduces rework difficulty, and improves product quality and production efficiency.

[0088] In optional embodiments, the value of n can be selected based on the polishing process and the type of wafer. For example, n can be set to 7, meaning that the wafer being polished is divided into seven zones, and at least one film thickness measurement point is set in each zone. This avoids the situation where, if there is only one measurement point, the film thickness of the wafer cannot be accurately determined if the data becomes invalid. Furthermore, the wafer surface may have non-uniformity, and the film thickness in different areas may vary. By setting measurement points in multiple zones, the thickness of the film on the wafer surface can be better inspected. By adjusting the pressure applied to each zone of the wafer in real time, it is possible to avoid insufficient or excessive removal of film in different areas during the polishing process.

[0089] After polishing the non-compliant partitions of the wafer, return to step III to re-check whether the wafer parameters of the wafer partitions meet the standards. Repeat steps III to IV until the wafer parameters of all partitions of the wafer meet the standards, then proceed to step V.

[0090] In step V, the polished wafer is unloaded, and the process returns to step I.

[0091] In step V, once the parameters of all wafer partitions meet the standards, the polished wafer can be unloaded, and the process can return to step I to start a new round of wafer polishing.

[0092] This embodiment illustrates that when insufficient or excessive removal of material is detected during the initial polishing of a wafer, the pressure of the partitioned areas can be adjusted in real time through the development, extension, and combined application of a dynamic adjustment model. This enables dynamic rework of the partitioned areas, achieving the principle of automatic pressure / time balance for automatic partitioned rework, thus meeting the requirements of the CMP process for composite films and reducing product yield loss and rework rate.

[0093] This automated rework function, which divides the entire wafer into regions, reduces manual intervention, improves processing efficiency, and allows for precise repolishing of substandard areas, avoiding repeated processing of the entire wafer, reducing material consumption and costs, and improving the overall quality of the product.

[0094] Figure 2 This is a schematic diagram of the polishing process of one embodiment of the wafer polishing method of the present invention.

[0095] exist Figure 2 In the embodiment, a composite film wafer is schematically shown. Before polishing, the wafer comprises a three-layer structure, from top to bottom: a first film layer 10, a second film layer 20, and a silicon substrate 30. After primary polishing of the wafer according to a first polishing formula, the first film layer 10 is initially polished away, exposing the second film layer 20. However, in certain areas, the material of the first film layer 10 is not completely removed, and some material of the first film layer 10 remains on the surface of the second film layer 20. After secondary polishing of the wafer according to a dynamic adjustment model, the first film layer 10 on the wafer surface is completely removed, exposing the complete second film layer 20 of the wafer.

[0096] Figure 3 A schematic block diagram of an embodiment of a wafer polishing apparatus according to the present invention is shown. The diagram illustrates the structure and signal transmission of the wafer polishing apparatus.

[0097] like Figure 3 As shown, a wafer polishing equipment includes at least a polishing module, an endpoint detection module, and a dynamic adjustment module.

[0098] The polishing module is responsible for polishing the wafer. In an optional embodiment, the polishing module performs primary polishing on the wafer according to a first polishing formula sent by the dynamic adjustment module, or secondary polishing on the wafer according to a second polishing formula. The polishing module may include a polishing pad, a polishing head, and a liquid supply device. The polishing pad is covered with a polishing pad for polishing the wafer. The polishing head can hold the wafer through a conductive rubber gas film. The wafer is pressed against the polishing pad on the polishing pad by the polishing pad. The liquid supply device sprays polishing liquid onto the surface of the polishing pad. Under the chemical action of the polishing liquid, the relative movement between the polishing pad and the polishing pad causes the wafer to rub against the polishing pad, thereby achieving polishing.

[0099] The endpoint detection module can detect wafer parameters and stop polishing using endpoint detection technology, thus controlling the termination of the polishing process. Simultaneously, the endpoint detection module can also send the detection results of wafer parameters to the dynamic adjustment module. The endpoint detection technology has already been described above and will not be repeated here.

[0100] The dynamic adjustment module can receive the detection results of the wafer parameters sent by the endpoint detection module, generate a second polishing formula, and send the first polishing formula or the second polishing formula to the polishing module.

[0101] The control polishing mechanism, which combines a polishing module, an endpoint detection module, and a dynamic adjustment module, enables dynamic optimization and adjustment of wafer polishing, ensuring the accuracy of the polishing process and meeting wafer quality standards.

[0102] Figure 4 A structural block diagram of an embodiment of a data processing device according to the present invention is shown schematically.

[0103] As shown in the figure, the data processing device may include at least a memory and a processor. The memory may be used to store computer-executable instructions or computer programs. In this embodiment, the memory may store wafer polishing control algorithms and film thickness detection algorithms, and save preset polishing parameters and polishing recipes, such as polishing time and polishing pressure. The processor may be used to execute the computer-executable instructions or computer programs stored in the memory to implement the wafer polishing method of any of the foregoing embodiments.

[0104] This embodiment achieves various computational and control tasks in the wafer polishing control method through the coordinated work of memory and processor, ensuring high-quality and high-efficiency processing of the wafer surface.

[0105] To achieve the foregoing objectives, another aspect of the present invention provides a computer-readable storage medium. The computer-readable storage medium may store computer-executable instructions or a computer program, which, when executed by a processor, implement the wafer polishing method of any of the foregoing embodiments.

[0106] It should be noted that the computer-readable storage medium described above in this invention can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this invention, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0107] To achieve the foregoing objectives, another aspect of the present invention provides a computer program. The computer program may include computer-executable instructions or a computer program that, when executed by a processor, enables the implementation of the wafer polishing method of any of the foregoing embodiments.

[0108] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including but not limited to object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0109] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0110] The above embodiments are only used to illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for chemical mechanical polishing of wafers, characterized in that, The polishing method includes: Step 1: Load the wafer to be polished; Step II: Read in the first polishing formula, perform primary polishing on the wafer according to the first polishing formula, and stop the primary polishing by endpoint detection technology; Step III: Detect the wafer parameters of all partitions of the wafer and determine whether the wafer parameters of all partitions of the wafer meet the standard. If the wafer parameters of all partitions meet the standard, proceed to step V. If the wafer parameters of all or some partitions do not meet the standard, proceed to step IV. Step IV: Obtain a second polishing formula based on the wafer parameters of all the partitions by dynamically adjusting the model, perform secondary polishing on the non-compliant partitions of the wafer based on the second polishing formula, and return to Step III; Step V: Unload the polished wafer and return to step I; The dynamic adjustment model includes a calculation model for the polishing pressure of each partition of the wafer, and the calculation model for the polishing pressure is as follows: Where P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum value of the wafer parameters of partition Z[i], i = 1, 2, ..., n, Target is the target wafer parameter value, n is the number of partitions of the wafer, k is the empirical coefficient, Thk_Offset_Spec is the target control line, and the Step function is defined as Step(a, b, c) (ab>c is 1, ab≤c is 0).

2. The polishing method as described in claim 1, characterized in that, The parameters of the first polishing formula and the second polishing formula include polishing time, holding ring pressure, and polishing pressure on each partition of the wafer.

3. The polishing method as described in claim 1, characterized in that, The endpoint detection technology includes an eddy current endpoint detection method and / or an optical endpoint detection method and / or a motor torque endpoint detection method. In the eddy current endpoint detection method, the film thickness of the wafer is measured using the eddy current detection principle, and in the optical endpoint detection method, the film thickness of the wafer is measured using the optical detection principle.

4. The polishing method as described in claim 1, characterized in that, The wafer parameters include the film thickness of the wafer.

5. The polishing method as described in claim 4, characterized in that, The measurement principle for the film thickness of the partition of the wafer includes eddy current detection principle and / or optical detection principle.

6. The polishing method as described in claim 5, characterized in that, The optical detection principle uses light of a certain wavelength to irradiate the wafer surface and obtains the film thickness of the wafer by analyzing the reflected wavelength. The lower limit of the goodness of fit is set to 0.

98. The goodness of fit is the degree of fit between the actual measured reflection wavelength curve and the wavelength curve calibrated by the machine. If the goodness of fit is lower than the lower limit, the measurement is repeated or a new measurement point is selected.

7. The polishing method as described in claim 1, characterized in that, At least one measurement point is set at each of the partitions of the wafer.

8. The polishing method as described in claim 1, characterized in that, The dynamic adjustment model includes a calculation model for polishing time, which is as follows: Where T is the polishing time, PreZ[i]PointMax is the maximum value of the wafer parameters in the Z[i] partition, i = 1, 2, ..., n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions of the wafer, and RR is the removal rate.

9. The polishing method as described in claim 1, characterized in that, The first polishing formula is a pre-set standard formula, and the second polishing formula is generated and adjusted in real time by the dynamic adjustment model based on the detection results of the wafer parameters.

10. A wafer polishing device, characterized in that, The wafer polishing equipment is used to perform the polishing method as described in any one of claims 1 to 9, the wafer polishing equipment comprising: A polishing module performs primary polishing on a wafer according to a first polishing formula sent by a dynamic adjustment module, or secondary polishing on a wafer according to a second polishing formula. The polishing module includes a polishing disk, a polishing head, and a liquid supply device. The polishing disk is covered with a polishing pad for polishing the wafer. The polishing head is loaded with the wafer and is pressed against the polishing pad on the polishing disk by the polishing head. The liquid supply device sprays polishing liquid onto the surface of the polishing pad. Under the action of the polishing liquid, the wafer is polished by friction between the polishing head and the polishing pad through the relative movement of the polishing head and the polishing pad. The endpoint detection module performs wafer parameter detection on the wafer and stops polishing using endpoint detection technology. The endpoint detection module sends the detection results of the wafer parameters to the dynamic adjustment module. The dynamic adjustment module receives the detection results of the wafer parameters sent by the endpoint detection module, generates the second polishing formula, and sends the first polishing formula or the second polishing formula to the polishing module.

11. A data processing device, characterized in that, The data processing device includes: The memory is used to store computer-executable instructions or computer programs; A processor, which, when executing computer-executable instructions or computer programs stored in the memory, implements the polishing method as described in any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions or computer programs that, when executed by a processor, implement the polishing method as described in any one of claims 1 to 9.

13. A computer program, characterized in that, The computer program includes computer-executable instructions or a computer program, which, when executed by a processor, implement the polishing method as described in any one of claims 1 to 9.

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