Chemical mechanical polishing method and apparatus

Abstract

The embodiment of the invention provides a chemical mechanical polishing method and device for wafer processing. The chemical mechanical polishing method comprises the steps that historical polishing pressure of all areas of a polishing head of the chemical mechanical polishing device is obtained; determining a predicted removal rate of each region according to the obtained historical polishing pressure; the predicted removal rate of at least one region is determined according to the historical polishing pressure of the region and at least one other region except the region; and according to the predicted removal rate, the historical polishing pressure and the target removal amount of each area, the polishing time needed by current polishing and the predicted polishing pressure of each area are determined. According to the embodiment of the invention, when the predicted removal rate of a certain region is determined, not only is the historical polishing pressure of the region considered, but also the historical polishing pressures of other regions are considered, so that the predicted removal rate of each region can be predicted more accurately, the deviation between the actual removal amount and the target removal amount of the wafer is remarkably reduced, and the yield of the wafer is improved. And the phenomenon of local over-throwing or under-throwing is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor wafer processing technology, and in particular, to a chemical mechanical polishing method and device. Background Art

[0002] In the field of semiconductor wafer processing technology, chemical mechanical polishing (CMP) is a process that combines chemical reaction and mechanical action to flatten the wafer surface. Generally speaking, the polishing head is divided into multiple areas, and during polishing, different polishing pressures are applied to each area to meet the polishing requirements of different parts of the wafer.

[0003] However, in the related art, when polishing the wafer, the polishing pressure applied to each area is the pressure value of the area during the last polishing, resulting in a large difference between the actual removal amount and the target removal amount of each area, which seriously affects the polishing effect. Summary of the invention

[0004] In view of this, embodiments of the present application provide a chemical mechanical polishing method and apparatus to at least partially solve the above problems.

[0005] According to a first aspect of an embodiment of the present application, a chemical mechanical polishing method is provided for wafer processing, the method comprising the following steps: obtaining the historical polishing pressure of each area of ​​a polishing head of a chemical mechanical polishing device; determining a predicted removal rate of each of the areas based on the acquired historical polishing pressure; wherein the predicted removal rate of at least one of the areas is determined based on the historical polishing pressure of the area and at least one other area outside the area; determining the polishing time required for current polishing and the predicted polishing pressure of each of the areas based on the predicted removal rate, historical polishing pressure and target removal amount of each of the areas.

[0006] Furthermore, in the above-mentioned chemical mechanical polishing method, determining the predicted removal rate of each of the regions based on the acquired historical polishing pressure further includes: establishing a multivariate linear regression model between the removal rate of each region and the historical polishing pressure of the region and at least one other region outside the region; determining the weight value of the historical polishing pressure of each of the regions in the multivariate linear regression model; and determining the predicted removal rate of each region based on the determined multivariate linear regression model and the historical polishing pressure of each region and the corresponding weight value.

[0007] Furthermore, in the above-mentioned chemical mechanical polishing method, determining the weight value of the historical polishing pressure of each area in the multivariate linear regression model further includes: obtaining the historical removal rate of each area of ​​the polishing head of the chemical mechanical polishing device; bringing the historical removal rate and historical polishing pressure of each area into the multivariate linear regression model in turn; and fitting the weight value of the historical polishing pressure of each area.

[0008] Furthermore, in the above-mentioned chemical mechanical polishing method, the polishing time required for the current polishing and the predicted polishing pressure of each area are determined based on the predicted removal rate, historical polishing pressure and target removal amount of each area, further including: constructing a pressure constraint function based on the predicted polishing pressure and historical polishing pressure of each area; constructing a removal amount constraint function based on the target removal amount and predicted removal amount of the current polishing of each area; wherein the predicted removal amount is determined based on the predicted removal rate and the polishing time; constructing an objective function based on the pressure constraint function and the removal amount constraint function; and determining the polishing time and the predicted polishing pressure of each area based on the constructed objective function.

[0009] Furthermore, in the chemical mechanical polishing method, the polishing time and the predicted polishing pressure of each area are determined based on the constructed objective function, and further: a single-objective optimization algorithm can be used to obtain the polishing time and the predicted polishing pressure of each area.

[0010] Furthermore, in the chemical mechanical polishing method, the objective function constructed based on the pressure constraint function and the removal amount constraint function is:

[0011]

[0012] In the above formula: C is the objective function, f i (X i ,X i ′ ) is the pressure constraint function of the ith region, W i is the weight coefficient corresponding to the pressure constraint function of the ith region, X i ′ is the historical polishing pressure of the ith region, X i is the predicted polishing pressure of the ith region, g j (Y j ,T,A) is the removal constraint function of the jth region, W j is the weight coefficient corresponding to the removal constraint function of the jth region, A j is the target removal amount of the current polishing of the jth region, T is the polishing time, and Y j is the current removal rate of the jth area, the value of i is [1,n], the value of j is [1,n], and n is the total number of polishing head areas.

[0013] Furthermore, in the chemical mechanical polishing method, the pressure constraint function is: f(X i ,X i ′ )=X i ′ -X i Or f(X i ,X i ′ )=w i (X i ′ -X i ), where w i is the weight coefficient of the ith region.

[0014] Furthermore, in the chemical mechanical polishing method, the removal amount constraint function is: g(A j ,Y j ,T)=A j -Y j *T.

[0015] Furthermore, in the above chemical mechanical polishing method, the area of ​​the polishing head includes an adjustable polishing pressure area; and the area in which the historical polishing pressures of various areas of the polishing head of the chemical mechanical polishing device are obtained is the adjustable polishing pressure area.

[0016] Furthermore, in the above chemical mechanical polishing method, the polishing head area also includes one or more polishing pressure fixing areas.

[0017] According to the second aspect of an embodiment of the present application, a chemical mechanical polishing device is provided, which includes a base, a polishing disk, a polishing pad, a polishing liquid supply device, a polishing head and a control unit; wherein the control unit is used to control the polishing pressure and polishing time of each area of ​​the polishing head according to any of the above-mentioned chemical mechanical polishing methods.

[0018] According to a third aspect of the embodiment of the present application, an electronic device is provided. The device includes: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus; the memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform an operation corresponding to any one of the above-mentioned chemical mechanical polishing methods.

[0019] According to a fourth aspect of an embodiment of the present application, a computer storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, any one of the above-mentioned chemical mechanical polishing methods is implemented.

[0020] According to a fifth aspect of an embodiment of the present application, a computer program product is provided, comprising computer instructions, wherein the computer instructions instruct a computing device to perform operations corresponding to any one of the above-mentioned chemical mechanical polishing methods.

[0021] The chemical mechanical polishing method provided in the embodiment of the present application, since the polishing process between the various regions of the wafer surface is not completely independent, other regions will affect the material removal of the current region. Based on this, the chemical mechanical polishing process of the embodiment of the present application adopts a more sophisticated removal rate prediction. When determining the predicted removal rate of a certain area, not only the historical polishing pressure of the area itself is considered, but also the historical polishing pressure of other areas is considered. Through this cross-regional data analysis, the predicted removal rate of each area can be predicted more accurately, thereby optimizing the pressure distribution of the polishing head on the wafer, significantly reducing the deviation between the actual removal amount of the wafer and the target removal amount, improving the flatness of the entire wafer surface, and also improving the uniformity and consistency of the wafer surface, reducing the phenomenon of local over-polishing or under-polishing, ensuring the quality of the wafer in subsequent integrated circuit manufacturing, and ultimately improving the reliability of the overall product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0023] Figure 1 A schematic diagram of the structure of a polishing device applicable to the chemical mechanical polishing method of an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the steps of a chemical mechanical polishing method provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of a process for determining the predicted removal rate of each area in an embodiment of the present application;

[0026] Figure 4 A schematic diagram of a process for determining the polishing time required for the current polishing and the predicted polishing pressure of each area in an embodiment of the present application;

[0027] Figure 5 This is a schematic diagram of the structure of an electronic device according to Embodiment 5 of the present application. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0029] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0030] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0031] See also Figure 1 , a polishing device 100 suitable for the chemical mechanical polishing method proposed in the embodiment of the present application is shown in the figure. As shown in the figure, the polishing device 100 mainly includes a base (not shown in the figure), a polishing disc 110, a polishing pad 120, a polishing liquid supply device 130, a trimmer 140, a loading and unloading platform 150 and a polishing head 160. Among them, the polishing disc 110 is arranged on the base, the polishing pad 120 is arranged on the polishing disc, and the polishing disc 110 can drive the polishing pad 120 to rotate. The polishing liquid supply device 150 is used to transport the polishing liquid to the polishing pad 120, the trimmer 140 is used to maintain and trim the polishing pad 120, the loading and unloading platform 150 is arranged on one side of the polishing disc 110, and the wafer is loaded onto the polishing head 160. The polishing head 160 is configured to receive the wafer to be polished from the loading and unloading platform 150 or transfer the polished wafer to the loading and unloading platform 150.

[0032] During polishing, the polishing head 160 moves with the wafer toward the polishing pad 120 to press the wafer against the rotating polishing pad 120. At the same time, the polishing head 160 rotates with the wafer, and the polishing liquid supply device 130 injects polishing liquid containing abrasives and chemical additives into the space between the wafer and the polishing pad 120. Under the combined effects of mechanical grinding and chemical reaction, the material on the wafer surface is evenly removed, thereby achieving the purpose of flattening.

[0033] Generally speaking, the polishing head 160 is divided into multiple independent areas. During polishing, polishing pressure can be applied to each area separately to meet the polishing requirements of different parts of the wafer. However, in the related art, the last polishing pressure of each area is generally used as the current polishing pressure required for the area, which makes the deviation between the actual removal amount of the wafer and the target removal amount large, seriously affecting the polishing effect.

[0034] Based on this, an embodiment of the present application proposes a chemical mechanical polishing method to at least partially solve the above problems.

[0035] The specific implementation of the embodiment of the present application is further explained below in conjunction with the accompanying drawings of the embodiment of the present application.

[0036] See also Figure 2 , Figure 2 A schematic flow chart of a chemical mechanical polishing method provided in an embodiment of the present application is shown.

[0037] As shown in the figure, the method includes the following steps:

[0038] Step S201 , obtaining the historical polishing pressure of each area of ​​the polishing head of the chemical mechanical polishing device.

[0039] It is understood that in chemical mechanical polishing, the polishing head is usually divided into a plurality of independent polishing areas. During polishing, polishing pressure is applied to each area independently to meet the polishing requirements of different parts of the wafer.

[0040] For each area, the historical polishing pressure may be the last polishing pressure of each area, or the average polishing pressure within a certain period of time, or the maximum pressure or minimum pressure within the period of time, etc., which may be determined according to actual conditions, and this embodiment does not impose any limitation thereto. The certain period of time may also be determined according to specific conditions, such as one day, one week, etc.

[0041] Step S202, determining the current removal rate of each region according to the acquired historical polishing pressure, wherein the current removal rate of at least one region is determined according to the historical polishing pressure of the region and at least one other region outside the region.

[0042] It can be understood that the removal rate refers to the rate at which material is removed from the wafer surface per unit time. Specifically, it can refer to the thickness of material removed from the wafer surface per unit time by the pressure and friction applied by the polishing head to the wafer surface.

[0043] In the actual polishing process, the polishing process between each area of ​​the wafer surface is not completely independent. The removal rate of each area is not only affected by the polishing pressure of the area, but also by the polishing pressure of other areas outside the area. The closer the distance, the greater the impact. Therefore, when calculating the predicted removal rate of each area in the embodiment of the present application, the predicted removal rate of each area can be determined based on the historical polishing pressure of the area and at least one other area outside the area. The predicted removal rate of a part of the area can also be determined according to this method, and the predicted removal rate of the other area is determined only based on the historical polishing pressure of the area.

[0044] Specifically, in the embodiments of the present application, two different methods can be used to calculate the predicted removal rate of each area: one method is that each area comprehensively considers the historical polishing pressure of the area and at least one other area outside the area to jointly determine the predicted removal rate of each area; the other method is to use this comprehensive consideration method only for some areas, and the predicted removal rate of other areas is calculated only based on the historical polishing pressure of the area.

[0045] For example, it is assumed that the polishing head is provided with three annular regions, namely, region 1, region 2, and region 3, and region 2 is placed between region 1 and region 3. The predicted removal rate of region 1 can be determined only based on the historical polishing pressures of region 1 and region 2, or region 1 and region 3, or can be determined based on the historical polishing pressures of region 1, region 2, and region 3 at the same time. The predicted removal rates of regions 2 and 3 can be determined only based on the historical polishing pressures of the region, or can be determined with reference to region 1, based on the historical polishing pressures of the region and any one or two other regions outside the region. Since region 2 is closer to region 1 than region 3, the influence of the historical polishing pressure of region 2 on the predicted removal rate of region 1 is greater than the influence of the historical polishing pressure of region 3 on the predicted removal rate of region 1. When calculating the predicted removal rate of region 1 based on regions 2 and 3 at the same time, the weight of the historical polishing pressure of region 2 can be considered to be greater than the weight of the historical polishing pressure of region 3.

[0046] Step S203 , determining the polishing time required for current polishing and the predicted polishing pressure of each region according to the predicted removal rate of each region, the historical polishing pressure and the target removal amount.

[0047] The target removal amount is the amount of material removed from the wafer surface by the polishing head during the current polishing process, and this value is a given known amount.

[0048] For a determined target removal amount, the greater the predicted removal rate of each region, the greater the predicted polishing pressure, and the less polishing time required.

[0049] Since the polishing process between each area of ​​the wafer surface is not completely independent, other areas will affect the material removal of the current area. Based on this, the chemical mechanical polishing process of the embodiment of the present application adopts a more sophisticated removal rate prediction. When determining the predicted removal rate of a certain area, not only the historical polishing pressure of the area itself is considered, but also the historical polishing pressure of other areas. Through this cross-regional data analysis, the predicted removal rate of each area can be predicted more accurately, thereby optimizing the pressure distribution of the polishing head on the wafer, significantly reducing the deviation between the actual removal amount of the wafer and the target removal amount, and improving the flatness of the entire wafer surface. At the same time, it also improves the uniformity and consistency of the wafer surface, reduces the phenomenon of local over-polishing or under-polishing, ensures the quality of the wafer in subsequent integrated circuit manufacturing, and ultimately improves the reliability of the overall product.

[0050] See also Figure 3 , Figure 3 This is a flow chart of determining the predicted removal rate of each area according to the acquired historical polishing pressure in the above step S202, which may specifically include the following steps:

[0051] Step S301 : establishing a multiple linear regression model between the removal rate of each region and the historical polishing pressure of the region and at least one other region outside the region.

[0052] During polishing, there is mutual coupling between the various areas, so when calculating the removal rate of one area, the polishing pressure of other areas can be considered.

[0053] In a specific implementation, a multivariate linear regression model can be established with the removal rate of each area as the dependent variable and the polishing pressure of each area as the independent variable. Specifically, the model can be:

[0054]

[0055] In the above formula, Y j is the removal rate of the jth area, X i is the polishing pressure of the i-th area, j∈[1,n], i∈[1,n], n is the total number of areas of the polishing head, β ji is the weight value corresponding to the polishing pressure of the ith area when calculating the removal rate of the jth area, and e is the random error.

[0056] It should be noted that, in specific implementation, when calculating the removal rate of each area, the same total random error can be used. For example, assuming that the polishing head is provided with three areas, area 1, area 2, and area 3, the removal rates of the three areas can be expressed as:

[0057] Y1=β 11 X1+β 12 X2+β 13 X3+e

[0058] Y2=β 21 X1+β 22 X2+β 23 X3+e

[0059] Y3=β 31 X1+β 32 X2+β 33 X3+e

[0060] Of course, different random errors may also be set for each region, which may be determined based on actual conditions, and this embodiment does not impose any limitation thereto.

[0061] Step S302, determining the weight value of the historical polishing pressure of each region in the multivariate linear regression model.

[0062] In a specific implementation, the above-mentioned weight values ​​can be fitted according to the historical removal rate and historical polishing pressure of each area.

[0063] Specifically, firstly, the historical removal rate data of each area of ​​the polishing head of the chemical mechanical polishing device and the corresponding historical polishing pressure data are obtained. Then, these data are input into the pre-set multiple linear regression model in turn, and the weight relationship between the historical polishing pressure of each area and its removal rate is fitted by statistical analysis method. In this process, mathematical fitting techniques such as least squares method can be used to determine these weight values ​​to ensure the accuracy and reliability of the model. Through such fitting, we can obtain specific quantitative indicators of the impact of polishing pressure on removal rate in each area, thereby providing data support for adjusting and optimizing the polishing process.

[0064] Step S303 , based on the determined multivariate linear regression model, the predicted removal rate of each region is determined according to the historical polishing pressure of each region and the corresponding weight value.

[0065] In step S301, once the weight values ​​in the multivariate linear regression model are determined, the model can be used to predict the removal rate of each region. Specifically, the historical polishing pressure data of each region can be input into the model, and the predicted removal rate of each region can be calculated by combining these historical polishing pressures with the weight values ​​fitted in step S302.

[0066] In specific implementation, the historical polishing pressure may be an actual pressure value in the last polishing operation, or an average value of multiple polishing pressure values, etc. It may be determined according to actual conditions, and this embodiment does not impose any limitation thereto.

[0067] See also Figure 4 , Figure 4 for Figure 2 The flow chart of step S203 is to determine the polishing time required for current polishing and the predicted polishing pressure of each region according to the predicted removal rate of each region, the historical polishing pressure and the target removal amount, which may specifically include the following steps:

[0068] Step S401 : constructing a pressure constraint function according to the predicted polishing pressure and the historical polishing pressure of each region.

[0069] In one embodiment, in order to more accurately control the polishing pressure of each region, a pressure constraint function may be introduced. The basic form of the function may be: f(X i ,X i ′ )=X i ′ -X i Among them, X i ′ Represents the historical polishing pressure of the current area, X i represents the predicted polishing pressure of the ith region. This function aims to i ′ Find X nearby i The optimal solution of the project is determined, and the search scope of the optimal solution is limited to avoid obtaining a solution that is out of engineering practice.

[0070] Furthermore, considering that different regions on the wafer surface may have different physical properties and polishing requirements, the pressure constraint function can be further optimized. Specifically, a weight coefficient can be added to each item of the pressure constraint function of each region to form a weighted pressure constraint function in the following form: f(X i ,X i ′ ,w i )=w i (X i ′ -X i ). Among them, w i is the weight coefficient for the ith region, which can be determined based on factors such as the material properties of the region, the polishing difficulty, and the historical polishing effect. In this way, different regions can be treated differently, making the model more accurate in predicting polishing pressure.

[0071] By introducing the weighted pressure constraint function, a more complete model can be obtained, which not only takes into account the historical polishing pressure of each area, but also better adapts to the specific polishing requirements of different areas on the wafer surface by adjusting the weight coefficient.

[0072] Step S402: construct a removal amount constraint function according to the target removal amount and the predicted removal amount of each area during the current polishing, wherein the predicted removal amount is determined according to the removal rate and the polishing time.

[0073] In specific implementation, in order to accurately control the removal amount during chemical mechanical polishing, a removal amount constraint function can be defined. The removal amount constraint function is to constrain the target removal amount to the vicinity of the predicted removal amount to limit the range of finding the optimal solution. Among them, the predicted removal amount is the product of the removal rate and the polishing time. The target removal amount of each area is a set known amount.

[0074] In one embodiment, the expression of the removal amount constraint function can be: g(A j ,Y j ,T)=A j -Y j *T. Among them, A j is the target removal amount of the current polishing of the jth area, that is, the total amount of material removal expected to be achieved in this area; T is the polishing time, Y j is the removal rate of the jth area.

[0075] In this embodiment, by applying the removal amount constraint function, it is possible to ensure that each area can achieve the predetermined removal amount target within a given polishing time. The core function of this function is that it links the three key parameters of target removal amount, removal rate and polishing time to form a dynamic adjustment mechanism. In actual operation, if g(A j ,Y j ,T)=A j -Y j *The value of T is not zero, indicating that there is a difference between the predicted removal amount and the target removal amount. At this time, it is necessary to adjust the polishing parameters, such as polishing pressure or polishing time, to narrow this difference.

[0076] Step S403, constructing an objective function based on the pressure constraint function and the removal amount constraint function.

[0077] In a specific implementation, the objective function may be:

[0078]

[0079] In the above formula: C is the objective function, f i (X i ,X i ′ ) is the pressure constraint function of the ith region, W i is the weight coefficient corresponding to the pressure constraint function of the ith region, X i ′ is the historical polishing pressure of the ith region, Xi is the predicted polishing pressure of the ith region, g j (Y j ,T,A) is the removal constraint function of the jth region, W j is the weight coefficient corresponding to the removal constraint function of the jth region, A j is the target removal amount of the current polishing of the jth region, T is the polishing time, and Y j is the current removal rate of the jth area, the value of i is [1,n], the value of j is [1,n], and n is the total number of polishing head areas.

[0080] The objective function in this embodiment is composed of two parts: the first part is a function related to the pressure constraint, and the second part is a function related to the removal amount constraint. The weight coefficient W of the pressure constraint function is i and the weight coefficient W of the removal constraint function j The pressure constraint function and the removal amount constraint function can be adjusted to the same magnitude so that they can be added together to form the objective function.

[0081] It should be noted that, in the specific implementation, W i and W j When setting, which area has a greater impact on the overall polishing of the wafer, then the weight coefficient W of the area i and W j It should also be set larger.

[0082] Step S404: determining the polishing time and the predicted polishing pressure of each area based on the constructed objective function.

[0083] In specific implementation, a single-objective optimization algorithm can be used to obtain the polishing time and the predicted polishing pressure in each area.

[0084] In one example, a gradient descent method may be used to find the optimal polishing time and the predicted polishing pressure for each region.

[0085] Specifically, the steps of using the gradient descent method to solve the optimal polishing time and the predicted polishing pressure in each area are as follows:

[0086] Step 1, initialization parameters: randomly select an initial solution, including an initial polishing time T1 and an initial polishing pressure X i ; Then set the initial learning rate (step size) of the gradient descent method; determine the stopping criterion, such as a preset number of iterations or a change in the objective function value less than a certain threshold.

[0087] Step 2, calculate the gradient: calculate the objective function C with respect to each parameter (polishing time T and polishing pressure X of each area) i). This usually involves computing partial derivatives of the objective function.

[0088] Step 3, update parameters: use gradient and learning rate to update polishing time T1 and initial polishing pressure X of each area i .

[0089] Evaluate the objective function: After updating the parameters, recalculate the value of the objective function C to evaluate whether the new parameters reduce the objective function value. If the preset number of iterations is reached or the change in the objective function is less than the stop threshold, stop the iteration. Otherwise, return to step 2 and continue to the next iteration.

[0090] When the stop criterion is reached, the algorithm stops and outputs the final polishing time T1 and the initial polishing pressure X of each area. i As the optimal solution.

[0091] In this embodiment, a single objective function is constructed, which combines the pressure constraint function and the removal amount constraint function to determine the optimal polishing time and the predicted polishing pressure of each area. Specifically, the pressure constraint function is used to constrain the predicted polishing pressure within a reasonable range, thereby narrowing the search space of the optimal solution and ensuring that the predicted pressure does not deviate too far from the actual required polishing pressure. At the same time, the removal amount constraint function optimizes the polishing process to ensure that the material removal amount in each polishing area can reach the predetermined target removal amount, and this process is completed within the specified polishing time. By minimizing the objective function, the embodiment of the present application obtains a set of optimized polishing parameters, so that a balance is achieved between the polishing pressure and removal amount in each area of ​​the wafer surface. This optimization process not only improves the polishing efficiency, but also ensures the uniformity of the wafer surface removal amount, effectively avoids the problem of local over-polishing or under-polishing, and can minimize the unevenness of the wafer surface caused by uneven removal, thereby improving the overall quality of the wafer. In addition, this embodiment not only optimizes the polishing process of the wafer, but also improves the yield and reliability in subsequent integrated circuit manufacturing, ensuring the performance and stability of the wafer in the entire production process.

[0092] In some embodiments, the polishing head is divided into a plurality of polishing pressure adjustable regions. In the embodiments of the present application, all regions involved in the steps of obtaining the historical polishing pressure of each region of the polishing head of the chemical mechanical polishing device, and determining the predicted removal rate of each region based on these historical polishing pressures, are all referred to as polishing pressure adjustable regions. These adjustable regions allow the polishing pressure to be optimized during the polishing process to meet different polishing requirements.

[0093] Optionally, the polishing head may also include a polishing pressure fixing area, which keeps the pressure constant throughout the polishing process. One or more such areas may be provided, which usually serve as a reference in the polishing process or are intended to meet specific process requirements. The presence of these fixed pressure areas ensures the stability of the polishing effect in certain key areas and provides a reference standard for the entire polishing process. Through this distinction, the present embodiment can more flexibly control the polishing process, optimize the removal rate, and maintain the consistency and reliability of the process.

[0094] The embodiment of the present application also proposes a chemical mechanical polishing device, which includes a base, a polishing disc, a polishing pad, a polishing liquid supply device, a polishing head and a control unit. The control unit is used to control the polishing pressure and polishing time of each area of ​​the polishing head according to any of the above chemical mechanical polishing methods.

[0095] Since the chemical mechanical polishing method has the above effects, the chemical mechanical polishing device using the chemical mechanical polishing method also has corresponding technical effects.

[0096] The present application also provides an electronic device, Figure 5 A schematic diagram of the structure of an electronic device proposed according to an embodiment of the present application is shown. The specific embodiment of the present application does not limit the specific implementation of the electronic device.

[0097] like Figure 5 As shown, the electronic device may include: a processor 502, a communications interface 504, a memory 506, and a communication bus 508. The processor 502, the communications interface 504, and the memory 506 communicate with each other through the communication bus 508. The communications interface 504 is used to communicate with other electronic devices or servers. The processor 502 is used to execute a program 510, which can specifically execute the relevant steps in the above-mentioned chemical mechanical polishing method embodiment.

[0098] Specifically, the program 510 may include program codes, which include computer operation instructions.

[0099] The processor 502 may be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the smart device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0100] The memory 506 is used to store the program 510. The memory 506 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0101] The program 510 may be specifically configured to enable the processor 502 to perform the following operations:

[0102] The specific implementation of each step in program 510 can refer to the corresponding description of the corresponding steps and units in the above-mentioned chemical mechanical polishing method embodiment, which will not be repeated here. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described equipment and modules can refer to the corresponding process description in the above-mentioned method embodiment, which will not be repeated here.

[0103] The chemical mechanical polishing method of this embodiment can be executed by any appropriate electronic device with data processing capability, including but not limited to: a server, a mobile terminal (such as a mobile phone, a PAD, etc.) and a PC, etc.

[0104] The embodiment of the present application further provides a computer storage medium on which a computer program is stored. When the program is executed by a processor, the chemical mechanical polishing method as described above is implemented.

[0105] The embodiment of the present application also proposes a computer program product, including computer instructions, which instruct a computing device to perform operations corresponding to any of the chemical mechanical polishing methods described above.

[0106] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0107] The above-described method according to the embodiment of the present application can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-transitory machine-readable medium downloaded through a network and will be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor, or hardware, the chemical mechanical polishing method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the chemical mechanical polishing method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the chemical mechanical polishing method shown herein.

[0108] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0109] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A chemical mechanical polishing method for wafer processing, characterized in that: The steps include: Obtain historical polishing pressure of each area of ​​a polishing head of a chemical mechanical polishing device; Determine the predicted removal rate of each of the regions according to the acquired historical polishing pressure; wherein the predicted removal rate of at least one of the regions is determined according to the historical polishing pressure of the region and at least one other region outside the region; The polishing time required for current polishing and the predicted polishing pressure for each of the regions are determined according to the predicted removal rate of each of the regions, the historical polishing pressure and the target removal amount.

2. The chemical mechanical polishing method according to claim 1, characterized in that: Determining the predicted removal rate of each of the regions according to the acquired historical polishing pressure further includes: Establishing a multiple linear regression model between the removal rate of each region and the historical polishing pressure of the region and at least one other region outside the region; Determining the weight value of the historical polishing pressure of each of the regions in the multivariate linear regression model; Based on the determined multivariate linear regression model, the predicted removal rate of each region is determined according to the historical polishing pressure of each region and the corresponding weight value.

3. The chemical mechanical polishing method according to claim 2, characterized in that: Determining the weight value of the historical polishing pressure of each of the regions in the multivariate linear regression model further includes: Obtaining historical removal rates of various regions of a polishing head of a chemical mechanical polishing device; Substituting the historical removal rate and historical polishing pressure of each area into the multivariate linear regression model in turn; The weight value of the historical polishing pressure of each area is fitted.

4. The chemical mechanical polishing method according to claim 1, characterized in that: The step of determining the polishing time required for current polishing and the predicted polishing pressure of each of the regions according to the predicted removal rate, historical polishing pressure and target removal amount of each of the regions further comprises: A pressure constraint function is constructed according to the predicted polishing pressure and the historical polishing pressure of each area; Constructing a removal amount constraint function according to the target removal amount and the predicted removal amount of each area during the current polishing; wherein the predicted removal amount is determined according to the predicted removal rate and the polishing time; Constructing an objective function based on the pressure constraint function and the removal amount constraint function; The polishing time and the predicted polishing pressure in each area are determined based on the constructed objective function.

5. The chemical mechanical polishing method according to claim 4, characterized in that: The polishing time and the predicted polishing pressure of each area are determined based on the constructed objective function, further comprising: The single-objective optimization algorithm can be used to obtain the polishing time and the predicted polishing pressure in each area.

6. The chemical mechanical polishing method according to claim 4, characterized in that: The objective function constructed based on the pressure constraint function and the removal amount constraint function is: In the above formula: C is the objective function, f i (X i ,X i ′ ) is the pressure constraint function of the ith region, W i is the weight coefficient corresponding to the pressure constraint function of the ith region, X i ′ is the historical polishing pressure of the ith region, X i is the predicted polishing pressure of the ith region, g j (Y j ,T,A) is the removal constraint function of the jth region, W j is the weight coefficient corresponding to the removal constraint function of the jth region, A j is the target removal amount of the current polishing of the jth region, T is the polishing time, and Y j is the current removal rate of the jth area, the value of i is [1,n], the value of j is [1,n], and n is the total number of polishing head areas.

7. The chemical mechanical polishing method according to claim 6, characterized in that: The pressure constraint function is: f(X i ,X i ′ )=X i ′ -X i Or f(X i ,X i ′ )=w i (X i ′ -X i ), where w i is the weight coefficient of the ith region.

8. The chemical mechanical polishing method according to claim 6, characterized in that: The removal amount constraint function is: g(A j ,Y j ,T)=A j -Y j *T.

9. The chemical mechanical polishing method according to any one of claims 1 to 8, characterized in that: The region of the polishing head includes a polishing pressure adjustable region; The region where the historical polishing pressure of each region of the polishing head of the chemical mechanical polishing device is obtained is the polishing pressure adjustable region.

10. The chemical mechanical polishing method according to claim 9, characterized in that: The polishing head region also includes one or more polishing pressure securing regions.

11. A chemical mechanical polishing device, characterized in that: It comprises a base, a polishing disc, a polishing pad, a polishing liquid supply device, a polishing head and a control unit; wherein the control unit is used to control the polishing pressure and polishing time of each area of ​​the polishing head according to the chemical mechanical polishing method as described in any one of claims 1 to 10.

12. An electronic device, characterized in that: include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the chemical mechanical polishing method according to any one of claims 1-10.

13. A computer storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the chemical mechanical polishing method as described in any one of claims 1 to 10 is implemented.

14. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the chemical mechanical polishing method as claimed in any one of claims 1 to 10.

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