Flatness control method, device, equipment and medium

Abstract

The present application relates to a flatness control method, device, equipment and medium, the method comprising: obtaining the thickness uniformity parameter and relative grinding amount of the current surface of the target wafer, the relative grinding amount being the difference between the current thickness value of the target wafer and the target thickness value; calculating the absolute grinding amount of the target wafer according to the thickness uniformity parameter, the relative grinding amount and the target correction model, the target correction model including the correlation between the absolute grinding amount and the thickness uniformity parameter and the relative grinding amount; controlling the machine to perform the preset chemical mechanical polishing process according to the absolute grinding amount. The above flatness control method not only saves the process time of CMP, avoids the scrapping of the target wafer, saves material loss, but also improves the efficiency of grinding of new products from the production line to the CMP process.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a flatness control method, device, equipment and medium. Background Art

[0002] In integrated circuit manufacturing, the Chemical Mechanical Polishing (CMP) process generally removes a thin film on the surface of the wafer through a series of complex mechanical and chemical actions to achieve the purpose of wafer flattening. In the process of trial running of new products with a new CMP machine, a lot of time is needed for trial and error. Usually, new products need to be tested multiple times to reach the target thickness and surface state, so that the wafer surface can achieve a better flatness.

[0003] However, the method of multiple trial runs of new products will affect the product yield and even cause the product to be scrapped, and the success rate is low. Therefore, a new flatness control method is urgently needed to improve the product yield and save the time and cost of trial runs of new products. Summary of the invention

[0004] The present application provides a flatness control method, device, equipment and medium, which can reduce the trial operation time and improve the success rate of the operation during the trial operation of a new product by the CMP process, ensure the thickness uniformity of different polishing areas of the new product after the chemical mechanical polishing process, and improve the efficiency of the machine trial operation.

[0005] According to some embodiments, one aspect of the present application provides a flatness control method for controlling a machine to perform a preset chemical mechanical polishing process on a target wafer, the flatness control method comprising: obtaining a thickness uniformity parameter and a relative polishing amount of a current surface of the target wafer, the relative polishing amount being the difference between a current thickness value of the target wafer and a target thickness value; calculating an absolute polishing amount of the target wafer according to the thickness uniformity parameter, the relative polishing amount and a target correction model, the target correction model comprising a correlation between the absolute polishing amount and the thickness uniformity parameter and the relative polishing amount; and controlling the machine to perform a preset chemical mechanical polishing process according to the absolute polishing amount.

[0006] In the above flatness control method, the absolute grinding amount of the target wafer is calculated by the thickness uniformity parameter, the relative grinding amount and the target correction model, and the machine is controlled to perform the preset chemical mechanical polishing process according to the absolute grinding amount. The target wafer is ground by the absolute grinding amount, and the information related to the surface morphology of the target wafer can be accurately obtained, and the grinding rate caused by the different thicknesses at different positions of the target wafer is improved, which leads to the need to grind the target wafer for multiple times to reach the grinding standard. In the traditional technology, when the CMP process is performed on the newly-offline products, the CMP machine will grind the new products for multiple times to achieve the preset thickness and better flattening. However, when grinding the new products according to the relative grinding amount, the grinding amount can only be estimated according to the thickness to be removed, and multiple grindings are performed to achieve the required thickness. In this case, the thickness required to be removed for products with different surface morphologies, that is, the relative grinding amount, is the same, but due to the different surface morphologies, the absolute grinding amount is different. Therefore, it is usually necessary to flatten the target wafer only by the relative grinding amount, and some wafers whose thickness does not meet the standard will be generated, which reduces the success rate and efficiency of grinding. The flatness control method provided in the present application can improve the polishing efficiency and yield of newly-offline products, namely, target wafers, thereby improving the overall performance of semiconductor devices.

[0007] In some of the embodiments, obtaining the thickness uniformity parameter of the current surface of the target wafer includes the following steps: obtaining historical data of wafers with different structures, the historical data including the absolute grinding amount and the corresponding corrected relative grinding amount of the wafers with different structures, the corrected relative grinding amount being the relative grinding amount corrected according to the thickness uniformity parameter; performing parameter fitting on the historical data to obtain a target fitting curve, the target fitting curve being the linear variation relationship between the absolute grinding amount and the corrected relative grinding amount; calculating the thickness uniformity parameter of the target wafer according to the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve.

[0008] In some embodiments, calculating the absolute grinding amount of the target wafer includes the following steps: calculating the absolute grinding amount Td of the target wafer according to the current thickness value pre thk, the target thickness value post thk target and the thickness uniformity parameter TR% of the target wafer according to the following formula:

[0009] Td=(pre thk*Q-post thk target)*(1-TR%)*M+N;

[0010] In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the correction coefficient of the constant term, and Q is the correction coefficient of the current thickness value of the target wafer.

[0011] In some of these embodiments, the absolute grinding volume is the volume of the target wafer actually removed by the grinding process.

[0012] In some of the embodiments, the current thickness value of the target wafer is the maximum value of thicknesses of various regions of the target wafer.

[0013] Another aspect of the embodiment of the present application provides a chemical mechanical polishing device, including: a polishing module, a parameter acquisition module, a calculation module and a control module. The polishing module is used to perform a preset chemical mechanical polishing process on a target wafer; the parameter acquisition module is used to obtain the thickness uniformity parameter and relative polishing amount of the current surface of the target wafer, and the relative polishing amount is the difference between the current thickness value of the target wafer and the target thickness value; the calculation module is electrically connected to the parameter acquisition module, and is used to calculate the absolute polishing amount of the target wafer according to the thickness uniformity parameter, the relative polishing amount and the target correction model, and the target correction model includes the correlation between the absolute polishing amount and the thickness uniformity parameter and the relative polishing amount; the control module is electrically connected to the calculation module and the polishing module, and is used to control the polishing module to perform the preset chemical mechanical polishing process according to the absolute polishing amount.

[0014] In the above-mentioned chemical mechanical polishing device, the calculation module substitutes the thickness uniformity parameters and relative grinding amount obtained in the parameter acquisition module into the target correction model, and can obtain the absolute grinding amount of the target wafer. Then, the control module controls the polishing module to execute the preset chemical mechanical polishing process according to the absolute grinding amount, so that the target wafer can obtain a structure with a target thickness value and a flat surface through a flattening process, thereby reducing the failure rate of grinding of new products and saving the time of grinding trial operation and the loss of the machine.

[0015] In some of the embodiments, the parameter acquisition module is also used to acquire historical data of wafers with different structures, the historical data including the absolute grinding amount and the corresponding corrected relative grinding amount of wafers with different structures, the corrected relative grinding amount being the relative grinding amount corrected according to the thickness uniformity parameter; and performing parameter fitting on the historical data to obtain a target fitting curve, the target fitting curve being the linear variation relationship between the absolute grinding amount and the corrected relative grinding amount; and being used to calculate the thickness uniformity parameter of the target wafer based on the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve.

[0016] In some of the embodiments, the calculation module is further used to calculate the absolute grinding amount Td of the target wafer according to the current thickness value pre thk of the target wafer, the target thickness value post thk target and the thickness uniformity parameter TR%, according to the following formula:

[0017] Td=(pre thk*Q-post thk target)*(1-TR%)*M+N;

[0018] In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the correction coefficient of the constant term, and Q is the correction coefficient of the current thickness value of the target wafer.

[0019] Another aspect of the embodiments of the present application provides a flatness control device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the flatness control method described in any one of the embodiments of the present application are implemented.

[0020] Another aspect of the embodiments of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the flatness control method described in any one of the embodiments of the present application are implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, they can also obtain drawings of other embodiments based on these drawings without paying any creative work.

[0022] Figure 1a-1b A schematic diagram of the structure of different surface morphologies of a wafer during a CMP process and a schematic diagram of a curve of the polishing rate at corresponding moments provided in an embodiment of the present application;

[0023] Figure 2a-2b A schematic diagram showing a comparison between a relative grinding amount and an absolute grinding amount of a wafer provided in an embodiment of the present application;

[0024] Figure 3 A schematic flow chart of a flatness control method provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of a target correction model provided in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of a chemical mechanical polishing device provided in an embodiment of the present application;

[0027] Figure 6 This is a coordinate diagram of the relationship between the grinding time and failure rate and different batches of products before and after the flatness control method provided by the present application is adopted in one embodiment of the present application.

[0028] Description of reference numerals:

[0029] 10. Substrate; 11. Drift region; 12. Isolation region; 13. Active region; 14. Gate structure; 15. Dielectric layer; 20. Parameter acquisition module; 30. Calculation module; 40. Control module; 50. Polishing module. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] In the case of using “including”, “having”, and “comprising” described herein, another component may be added unless a clear limiting term such as “only”, “consisting of”, etc. is used. Unless mentioned otherwise, a term in the singular form may include a plural form and should not be understood as being one in number.

[0033] The role of the CMP process is to use CMP equipment to make the wafer reach the target thickness and achieve surface flatness, which is convenient for the photolithography focus of the subsequent process. The wafer needs to measure the thickness after a CMP grinding to obtain the current thickness value and determine whether to perform the next grinding based on the target value. Different products and different process steps have different requirements for the thickness after CMP grinding. The thickness of the wafer after grinding should be within a reasonable error range. If the thickness deviates too much from the target value, it will affect the product yield and even cause the product to be scrapped. When a new product is put into the CMP process, a new process needs to be created and tested in pieces. According to the results of a test run, various parameters in the process are debugged and the test run continues until the thickness value of the product reaches the reasonable error range of the target value.

[0034] The current CMP process trial run method for new products is to estimate a time as the main grinding time based on the thickness value that needs to be removed, and then build a new process for trial run. However, due to different process requirements for different products, although the thickness value that needs to be removed in the before and after values ​​of the CMP process is the same, the grinding time is also different. Therefore, using the current trial run method to grind new products off the line will take a lot of time to trial and error. The success rate of achieving the target thickness value in a one-time trial run is very low, and it may even lead to product scrapping, serious waste of time and cost, and cause material loss and machine loss.

[0035] Based on the above technical problems, the present application provides a flatness control method, device, equipment and medium, which can reduce the trial run time and improve the success rate of the operation during the trial run of a new product by the CMP process, ensure the thickness uniformity of different polishing areas of the new product after the chemical mechanical polishing process, and improve the efficiency of the machine trial run.

[0036] See also Figure 1a-1b The experimental data show that the different surface morphologies of the same wafer during the CMP grinding process, that is, the grinding rate (Remove Rate, referred to as RR) of different thickness uniformities are different. At points A and C, the grinding rate is high in the early stage and decreases as the wafer grinding amount increases. At point B, the grinding rate is low in the early stage and increases as the wafer grinding amount increases. When the thickness uniformity reaches a certain level, the grinding rate maintains a stable value in each area of ​​the wafer surface. Therefore, the real-time relationship between the main grinding time and the wafer grinding amount during the wafer grinding trial run is not linearly fixed.

[0037] See also Figure 2a-2bThe wafer structure includes a substrate 10, a drift region 11 above the substrate 10, an isolation region 12 between adjacent drift regions 11, an active region 13 located inside the drift region 11 and having a different ion doping type from the drift region 11, a gate structure 14 located above the drift region 11 and the active region 13, and a dielectric layer 15 located above the gate structure 14, wherein the dielectric layer 15 has an uneven surface morphology. In the process of depositing the dielectric layer 15, for example, when performing chemical vapor deposition (CVD), the deposited dielectric layer 15 will replicate the surface morphology of the previous gate structure 14. Since the surface morphology of the dielectric layer 15 is uneven, the average density of the wafer under different thickness regions of the same layer is also different. The average density of the surface of the dielectric layer 15 is different at the beginning and the end of CMP polishing, resulting in a difference in the polishing rate at the beginning and the end. Therefore, when the surface morphology of the dielectric layer 15 with the same thickness is different, the polishing time required to remove the dielectric layer 15 with the same thickness value is different. Therefore, it is obviously not accurate enough to calculate the grinding time directly according to the thickness value to be removed, that is, the relative grinding amount, which will lead to an increased failure rate and reduced efficiency of the CMP process. The actual CMP process should be carried out based on the absolute grinding amount.

[0038] As an example, see Figure 3 The present application provides a flatness control method for controlling a machine to perform a preset chemical mechanical polishing process on a target wafer. The flatness control method includes:

[0039] Step S2: obtaining the thickness uniformity parameter and relative grinding amount of the current surface of the target wafer, where the relative grinding amount is the difference between the current thickness value and the target thickness value of the target wafer;

[0040] Step S4: calculating the absolute grinding amount of the target wafer according to the thickness uniformity parameter, the relative grinding amount and the target correction model, wherein the target correction model includes the correlation between the absolute grinding amount and the thickness uniformity parameter and the relative grinding amount;

[0041] Step S6: Control the machine to perform a preset chemical mechanical polishing process according to the absolute polishing amount.

[0042] In step S2, see Figure 3 In step S2, according to the parameter information of the target wafer, the thickness uniformity parameter and the relative grinding amount of the current surface of the target wafer are obtained. The thickness uniformity parameter reflects the surface morphology of the current surface of the target wafer, that is, the concave-convex situation or uniformity situation of the current surface, and the thickness uniformity parameter of the target wafer with different surface morphology is different.

[0043] In step S4, see Figure 3In step S4, the relative grinding amount is the total grinding amount used as a reference when the machine performs a preset chemical mechanical grinding process in the traditional technology. Compared with the absolute grinding amount, the relative grinding amount can only tell how much thickness the target wafer needs to remove, without considering the surface morphology of the target wafer and the total amount of material that actually needs to be removed. Therefore, multiple grindings are required to perform the chemical mechanical grinding process according to the relative grinding amount, and the volume removed by grinding and the thickness value after grinding cannot meet the standard at one time. After the grinding is completed, there will be too much or too little grinding, and even the wafer will be scrapped. The present application obtains the thickness uniformity parameters and relative grinding amount of the current surface of the target wafer, so that the grinding amount of the target wafer is more accurate and the success rate of grinding is improved.

[0044] In the above flatness control method, the absolute grinding amount of the target wafer is calculated by the thickness uniformity parameter, the relative grinding amount and the target correction model, and the machine is controlled to perform the preset chemical mechanical polishing process according to the absolute grinding amount. The target wafer is ground by the absolute grinding amount, and the information related to the surface morphology of the target wafer can be accurately obtained, and the grinding rate caused by the different thicknesses at different positions of the target wafer is improved, which leads to the need to grind the target wafer for multiple times to reach the grinding standard. In the traditional technology, when the CMP process is performed on the newly-offline products, the CMP machine will grind the new products for multiple times to achieve the preset thickness and better flattening. However, when grinding the new products according to the relative grinding amount, the grinding amount can only be estimated according to the thickness to be removed, and multiple grindings are performed to achieve the required thickness. In this case, the thickness required to be removed for products with different surface morphologies, that is, the relative grinding amount, is the same, but due to the different surface morphologies, the absolute grinding amount is also different. Therefore, it is usually necessary to perform multiple trials and errors to flatten the target wafer only by the relative grinding amount, and some wafers whose thickness does not meet the standard will be generated, which reduces the success rate and efficiency of grinding. The flatness control method provided in the present application can improve the polishing efficiency and yield of newly-offline products, namely, target wafers, thereby improving the overall performance of semiconductor devices.

[0045] As an example, see Figure 4 , obtaining the thickness uniformity parameter of the current surface of the target wafer, including the following steps:

[0046] Step S21: acquiring historical data of wafers with different structures, the historical data including absolute grinding amounts and corresponding corrected relative grinding amounts of wafers with different structures, the corrected relative grinding amount being the relative grinding amount corrected according to the thickness uniformity parameter;

[0047] Step S22: performing parameter fitting on the historical data to obtain a target fitting curve, wherein the target fitting curve is a linear variation relationship between the absolute grinding amount and the corrected relative grinding amount;

[0048] Step S23: Calculate the thickness uniformity parameter of the target wafer according to the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve.

[0049] In step S22, the structured wafer is a wafer equivalent to the target wafer and has been ground using a conventional CMP process. Product information of the structured wafer that has completed the current CMP process is obtained, i.e., historical data, the historical data including the absolute grinding amount and the corresponding corrected relative grinding amount of different structured wafers, and the absolute grinding amount and the corresponding corrected relative grinding amount of different structured wafers are different.

[0050] In step S22, refer to Figure 4 , the above historical data are fitted to obtain a line segment with a linear change relationship, namely the target fitting curve, which reflects the change relationship between the absolute grinding amount and the corrected relative grinding amount. In the experimental data of one embodiment, the absolute grinding amount of the structure wafer is y, and the corrected relative grinding amount of the structure wafer is x. The linear relationship of the target fitting curve is y=0.346x+2858.2, and the correlation coefficient R 2 It is 0.7317.

[0051] Although Figure 3 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, the execution of these steps is not strictly limited to the order, and these steps can be executed in other orders. Moreover, although Figure 3 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution of these sub-steps or stages is not necessarily carried out sequentially, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0052] As an example, calculating the absolute grinding amount of the target wafer includes the following steps: according to the current thickness value pre thk of the target wafer, the target thickness value post thk target and the thickness uniformity parameter TR%, the absolute grinding amount Td of the target wafer is calculated according to the following formula:

[0053] Td=(pre thk*Q-post thk target)*(1-TR%)*M+N;

[0054] In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the constant correction coefficient, and Q is the correction coefficient of the current thickness value of the target wafer, where M∈(0,1), N∈(0,1), and Q∈(0,1).

[0055] In the above calculation formula for the absolute grinding amount Td, the absolute grinding amount of the target wafer can be calculated based on the obtained thickness uniformity parameters and relative grinding amount, so that the originally rough CMP trial run process can be refined and optimized to enable the target wafer to reach the target thickness value and a better degree of flatness with only one trial run.

[0056] As an example, the absolute grinding amount is the volume of the target wafer actually removed during the grinding process. The absolute grinding amount reflects the total volume of actual materials that need to be removed from different target wafers with different surface morphologies. Grinding the target wafer using the absolute grinding amount can more accurately obtain a flat surface.

[0057] As an example, the current thickness value of the target wafer is the maximum value of the thickness of each region of the target wafer, that is, the thickness value of the position that the grinding head in the CMP machine first contacts when grinding the target wafer.

[0058] As an example, see Figure 5 The present application also provides a chemical mechanical polishing device, including: a polishing module, a parameter acquisition module, a calculation module and a control module. The polishing module is used to perform a preset chemical mechanical polishing process on a target wafer; the parameter acquisition module is used to obtain the thickness uniformity parameter and relative polishing amount of the current surface of the target wafer, and the relative polishing amount is the difference between the current thickness value of the target wafer and the target thickness value; the calculation module is electrically connected to the parameter acquisition module, and is used to calculate the absolute polishing amount of the target wafer according to the thickness uniformity parameter, the relative polishing amount and the target correction model, and the target correction model includes the correlation between the absolute polishing amount and the thickness uniformity parameter and the relative polishing amount; the control module is electrically connected to the calculation module and the polishing module, and is used to control the machine to perform the preset chemical mechanical polishing process according to the absolute polishing amount.

[0059] As an example, the polishing module includes a grinding head, a grinding pad, a turntable, a force-applying device, abrasives and an abrasive nozzle; the grinding head is used to press the wafer surface to be polished against the rough grinding pad, and is controlled by the control module to apply a set pressure to the grinding head to polish the target wafer; the surface of the grinding pad has special grooves to improve the uniformity of polishing, and the grinding pad may include a visual window for online detection; the turntable drives the grinding pad to rotate; the force-applying device acts on the grinding head and controls the pressure value of grinding the target wafer according to the absolute grinding amount; the abrasive is a mixture of grinding materials and chemical additives, and the materials used include quartz, aluminum dioxide and cerium oxide. The chemical additives used react with the part to be removed in the target wafer to weaken its connection with the silicon molecules to facilitate mechanical polishing. When executing the preset chemical mechanical polishing process, the target wafer is fixed at the bottom of the polishing head and the polishing pad is placed on the turntable. During polishing, the rotating polishing head presses on the rotating polishing pad with a certain pressure. Under the transmission of the polishing pad and the action of centrifugal force, the chemical additives in the abrasive react chemically with the surface material of the target wafer. The chemical reactants are removed from the surface of the target wafer through the micromechanical friction of the polishing material. The total amount removed is the absolute polishing amount, thereby achieving the target thickness value.

[0060] In the above-mentioned chemical mechanical polishing device, the calculation module substitutes the thickness uniformity parameters and relative grinding amount obtained in the parameter acquisition module into the target correction model, and can obtain the absolute grinding amount of the target wafer. Then, the control module controls the polishing module to execute the preset chemical mechanical polishing process according to the absolute grinding amount, so that the target wafer can obtain a structure with a target thickness value and a flat surface through a flattening process, thereby reducing the failure rate of grinding of new products and saving the time of grinding trial operation and the loss of the machine.

[0061] As an example, the parameter acquisition module is also used to acquire historical data of wafers with different structures, the historical data including the absolute grinding amount and the corresponding corrected relative grinding amount of wafers with different structures, the corrected relative grinding amount being the relative grinding amount corrected according to the thickness uniformity parameter; and performing parameter fitting on the historical data to obtain a target fitting curve, the target fitting curve being the linear variation relationship between the absolute grinding amount and the corrected relative grinding amount; and being used to calculate the thickness uniformity parameter of the target wafer based on the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve.

[0062] Specifically, the parameter acquisition module is also used to fit the above historical data to obtain a line segment with a linear change relationship, that is, a target fitting curve. The target fitting curve reflects the change relationship between the absolute grinding amount and the corrected relative grinding amount.

[0063] As an example, the calculation module is further used to calculate the absolute grinding amount Td of the target wafer according to the current thickness value pre thk of the target wafer, the target thickness value postthk target and the thickness uniformity parameter TR%, according to the following formula:

[0064] Td=(pre thk*Q-post thk target)*(1-TR%)*M+N;

[0065] In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the constant correction coefficient, and Q is the correction coefficient of the current thickness value of the target wafer, where M∈(0,1), N∈(0,1), and Q∈(0,1).

[0066] As an example, see Figure 6 , batches W2213, W2214, W2215 and W2216 are statistical data results obtained after multiple trial runs of the target wafer using the traditional chemical mechanical polishing process; batches W2217 and W2218 are statistical data results obtained after grinding the target wafer using the flatness control method provided in any embodiment of the present application. Among them, the obtained data results include the running time and grinding failure rate of each batch, and the grinding failure of the target wafer may include too little grinding, too much grinding, or the surface morphology after grinding is not flat enough. It can be seen that after multiple trial runs of the target wafer using the traditional chemical mechanical polishing process, the average running time of each batch is 12s and the average failure rate is 19.60%; and after grinding the target wafer using the flatness control method provided in any embodiment of the present application, the average running time of each batch is 4s, and the average failure rate is 0.00%. Compared with the traditional process, the running time and failure rate are greatly reduced, which improves the efficiency and yield of the CMP process for grinding new products.

[0067] As an example, the present application further provides a flatness control device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the flatness control method described in any one of the embodiments of the present application are implemented.

[0068] As an example, the present application further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the flatness control method described in any one of the embodiments of the present application are implemented.

[0069] As an example, the present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the flatness control method described in any one of the above-mentioned semiconductor structure preparation methods.

[0070] In the above-mentioned flatness control method, chemical mechanical polishing device, equipment, storage medium and computer program product, the absolute grinding amount is calculated to grind the target wafer, thereby reducing the number of trial runs and the rework process after the trial run failure, and avoiding the situation where the target wafer is scrapped due to excessive grinding during the trial run, thereby improving the efficiency of the trial run of new products from the offline to the CMP process, saving process time, material costs and machine losses.

[0071] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include non-volatile, volatile memory or a combination thereof. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM) or graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include a relational database, a non-relational database, or a combination thereof. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, or a data processing logic device based on quantum computing, etc., but are not limited thereto.

[0072] Please note that the above embodiments are for illustrative purposes only and are not intended to limit the present application.

[0073] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A flatness control method, characterized in that: The method is used to control a machine to perform a preset chemical mechanical polishing process on a target wafer, and the method includes: Obtaining a thickness uniformity parameter and a relative grinding amount of the current surface of the target wafer, wherein the relative grinding amount is a difference between a current thickness value and a target thickness value of the target wafer; Calculating the absolute grinding amount of the target wafer according to the thickness uniformity parameter, the relative grinding amount and a target correction model, wherein the target correction model includes a correlation between the absolute grinding amount and the thickness uniformity parameter and the relative grinding amount; Controlling the machine to perform the preset chemical mechanical polishing process according to the absolute polishing amount; Wherein, the obtaining of the thickness uniformity parameter of the current surface of the target wafer includes: Acquire historical data of wafers with different structures, wherein the historical data includes absolute grinding amounts and corresponding corrected relative grinding amounts of wafers with different structures, wherein the corrected relative grinding amount is the relative grinding amount corrected according to a thickness uniformity parameter; Performing parameter fitting on the historical data to obtain a target fitting curve, wherein the target fitting curve is a linear variation relationship between the absolute grinding amount and the corrected relative grinding amount; Calculating the thickness uniformity parameter of the target wafer according to the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve; The calculating the absolute grinding amount of the target wafer comprises: According to the current thickness value pre thk, the target thickness value post thk target and the thickness uniformity parameter TR% of the target wafer, the absolute grinding amount Td of the target wafer is calculated according to the following formula: Td=(pre thk*Q-post thk target)*(1-TR%)*M+N; In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the correction coefficient of the constant term, and Q is the correction coefficient of the current thickness value of the target wafer.

2. The flatness control method according to claim 1, characterized in that: The absolute grinding amount is the volume of the target wafer actually removed during the grinding process.

3. The flatness control method according to claim 1, characterized in that: The current thickness value of the target wafer is the maximum value of the thickness of each region of the target wafer.

4. A chemical mechanical polishing device, characterized in that: include: A polishing module, for performing a preset chemical mechanical polishing process on a target wafer; A parameter acquisition module, used to acquire a thickness uniformity parameter and a relative grinding amount of the current surface of the target wafer, wherein the relative grinding amount is a difference between a current thickness value and a target thickness value of the target wafer; a calculation module, electrically connected to the parameter acquisition module, for calculating the absolute grinding amount of the target wafer according to the thickness uniformity parameter, the relative grinding amount and a target correction model, wherein the target correction model includes a correlation between the absolute grinding amount and the thickness uniformity parameter and the relative grinding amount; a control module, electrically connected to the calculation module and the polishing module, and configured to control the polishing module to perform the preset chemical mechanical polishing process according to the absolute polishing amount; The parameter acquisition module is further used to acquire historical data of wafers with different structures, wherein the historical data includes absolute grinding amounts and corresponding corrected relative grinding amounts of wafers with different structures, wherein the corrected relative grinding amount is the relative grinding amount corrected according to the thickness uniformity parameter; and parameter fitting is performed on the historical data to obtain a target fitting curve, wherein the target fitting curve is a linear variation relationship between the absolute grinding amount and the corrected relative grinding amount; and for calculating the thickness uniformity parameter of the target wafer according to the absolute grinding amount of the target wafer, the corresponding corrected relative grinding amount and the target fitting curve; The calculation module is also used to calculate the absolute grinding amount Td of the target wafer according to the current thickness value pre thk of the target wafer, the target thickness value post thktarget and the thickness uniformity parameter TR%, according to the following formula: Td=(pre thk*Q-post thk target)*(1-TR%)*M+N; In the above formula, M is the correction coefficient of the thickness uniformity parameter of the target wafer, N is the correction coefficient of the constant term, and Q is the correction coefficient of the current thickness value of the target wafer.

5. A flatness control device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the flatness control method according to any one of claims 1 to 3 are implemented.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the flatness control method according to any one of claims 1 to 3 are implemented.

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