Wafer measurement point determination method, electronic equipment and storage medium

Abstract

The embodiment of the invention provides a method for determining a measurement point of a wafer, electronic equipment and a storage medium. The method for determining the measurement points of the wafer comprises the following steps: performing one or more rejecting operations on initial measurement points of the wafer until a first preset requirement is met, and determining the measurement points except for all the measurement points deleted at the end in the initial measurement points as final measurement points, the elimination operation comprises the following steps: determining a first compensation residual error of the current measurement point; and determining a second compensation residual error of the first residual measurement point, calculating a residual error difference index value, if the residual error difference index value is smaller than or equal to a first difference threshold value, deleting at least the to-be-selected measurement point from the current measurement points so as to update the current measurement points, and otherwise, determining that the to-be-selected measurement point cannot be deleted. And the measurement point is automatically determined. The measurement points are screened through the residual difference index value representing the compensation residual change degree, redundant measurement points in the final measurement points are avoided, and it is guaranteed that the final measurement points are fully covered.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology. More specifically, it relates to a method for determining measurement points on a wafer, an electronic device, a storage medium, and a computer program product. Background Technology

[0002] In wafer lithography, overlay error describes the alignment deviation between the current layer and the reference layer. The magnitude of the overlay error directly determines device performance and production yield. Measurement points are typically representative physical locations selected on the current layer of the wafer for measuring overlay error. The goal is for these measurement points to efficiently and comprehensively characterize the overlay error distribution across the entire wafer, providing a basis for process correction in the lithography compensation model. Too many measurement points during the overlay process will lead to longer measurement times and affect production efficiency; too few measurement points will affect the process correction effect and reduce production yield.

[0003] In related technologies, measurement points are usually determined manually based on human experience, which can lead to problems such as redundant or incomplete coverage of measurement points. Summary of the Invention

[0004] The present invention was proposed in view of the above-mentioned problems.

[0005] According to one aspect of the present invention, a method for determining measurement points on a wafer is provided. The method includes: performing one or more rejection operations on initial measurement points of the wafer until a first preset requirement is met, and determining the measurement points other than all measurement points deleted at the end of the initial measurement points as final measurement points, wherein the rejection operation includes:

[0006] Determine the first compensation residual for the current measurement point;

[0007] Determine candidate measurement points from the current measurement points;

[0008] Determine the second compensation residual of the first remaining measurement point in the current measurement points, wherein the first remaining measurement point is another measurement point other than the candidate measurement point in the current measurement points;

[0009] Based on the difference between the first compensation residual and the second compensation residual, the residual difference index value is calculated, where the larger the difference, the larger the residual difference index value.

[0010] If the residual difference index value is less than or equal to the first difference threshold, then at least one candidate measurement point is deleted from the current measurement point to update the current measurement point.

[0011] If the residual difference index value is greater than the first difference threshold, then the candidate measurement points cannot be deleted.

[0012] For example, when the elimination operation is performed for the first time, the current measurement point includes measurement points located in different exposure fields. One or more elimination operations are performed until the first preset requirement is met, which includes: a first elimination stage of performing multiple elimination operations; in the first elimination stage, each time the elimination operation is performed, the determined candidate measurement points are located in different exposure fields, and if the residual difference index value is less than or equal to the first difference threshold, then all measurement points in the exposure field corresponding to the candidate measurement point are deleted from the current measurement point to update the current measurement point.

[0013] For example, in the first rejection phase, each time a rejection operation is performed, the candidate measurement point is a measurement point located in the central region of the exposure field.

[0014] For example, performing one or more rejection operations until the first preset requirement is met also includes a second rejection stage of performing multiple sets of rejection operations; wherein, when the second preset requirement is met, the process transitions from the first rejection stage to the second rejection stage, each set of rejection operations includes at least one rejection operation performed consecutively, the candidate measurement points determined in each set of rejection operations are located in the same exposure field, and the candidate measurement points determined in different sets of rejection operations are located in different exposure fields.

[0015] For example, at least one set of rejection operations includes multiple steps executed sequentially; in at least one step of the multiple steps, at least two rejection operations are executed synchronously, and the candidate measurement points determined in the synchronously executed rejection operations are different; at least one set of rejection operations constitutes multiple operation flows, each operation flow includes at least one first rejection operation, each first rejection operation is executed in one step of the multiple steps, and in each operation flow that also includes a second rejection operation, the current measurement point when the second rejection operation is executed is the measurement point obtained after the candidate measurement point is deleted in the first rejection operation, and the first rejection operation and the second rejection operation are rejection operations executed in two steps of the same operation flow that are executed sequentially in the multiple steps.

[0016] For example, the second preset requirement includes: the number of exposure fields in which the deleted measurement points are located is equal to the number of deleted fields threshold, and / or the deletion operation in the first deletion stage has traversed all exposure fields.

[0017] For example, the first preset requirement includes: all measurement points in the current measurement point cannot be deleted, and / or the number of current measurement points is equal to the measurement point number threshold.

[0018] For example, there are synchronous elimination operations in the elimination operation, wherein the candidate measurement points determined in the synchronous elimination operations are different.

[0019] For example, determining a candidate measurement point among the current measurement points includes: determining one measurement point among the current measurement points as a candidate measurement point.

[0020] According to another aspect of the present invention, an electronic device is also provided, comprising: a processor and a memory, wherein the memory stores computer program instructions, which, when executed by the processor, are used to perform the method for determining measurement points of a wafer as described above.

[0021] According to another aspect of the present invention, a storage medium is also provided, on which program instructions are stored, which, when executed, are used to perform the method for determining measurement points of a wafer as described above.

[0022] According to another aspect of the present invention, a computer program product is also provided, comprising computer program instructions which, when executed, are used to perform the method for determining measurement points of a wafer as described above.

[0023] In the above technical solution, one or more elimination operations are performed until the first preset requirement is met, and the measurement points other than those deleted at the end are determined as the final measurement points. Through the elimination operation, measurement points with relatively small impact on the compensation residual are removed, i.e., measurement points whose compensation residual does not change significantly before and after deletion. Therefore, measurement points can be determined intelligently and automatically. By screening measurement points using the residual difference index value, which represents the degree of change in the compensation residual, redundant measurement points can be avoided in the final measurement points, while ensuring comprehensive coverage of the final measurement points. This improves the measurement efficiency for the final measurement points and ensures the lithographic compensation effect.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0025] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0026] Figure 1 A schematic flowchart of a rejection operation according to an embodiment of the present invention is shown;

[0027] Figure 2 A schematic diagram of a set of steps and operation flow in a rejection operation according to an embodiment of the present invention is shown;

[0028] Figure 3 A schematic block diagram of an electronic device according to an embodiment of the present invention is shown. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a subset of embodiments of the present invention.

[0030] To at least address the aforementioned technical problems, this invention provides a method for determining measurement points on a wafer. In this method, one or more rejection operations are performed on the initial measurement points of the wafer. These rejection operations continue until a first preset requirement is met, and the measurement points other than those deleted at the end of the initial measurement points are determined as the final measurement points. This method allows for the screening of initial measurement points, identifying suitable points as final measurement points, ensuring comprehensive coverage of critical areas of the wafer while avoiding measurement point redundancy. This method can be applied to any electronic device, i.e., executed by any electronic device. Specifically, this method can be executed by the processor of any electronic device.

[0031] For example, the method for determining the measurement points of a wafer includes performing one or more rejection operations on the initial measurement points of the wafer. The rejection operation continues until a first preset requirement is met. Measurement points other than all measurement points deleted at the end of the process from the initial measurement points can be determined as the final measurement points.

[0032] Each rejection operation is performed on the current measurement point, and the current measurement point for the first rejection operation is the initial measurement point of the wafer. In some embodiments, all measurement points on the current layer of the wafer can be obtained as the current measurement point, i.e., the initial measurement point, when the rejection operation is first performed. In other embodiments, manually selected measurement points can be used as the initial measurement points. In still other embodiments, any existing or future developed method can be used to determine the initial measurement point, such as using an artificial intelligence model. In some rejection operations, one or more candidate measurement points in the current measurement point may be successfully rejected, thereby updating the current measurement point. The next rejection operation is performed on the updated current measurement point. In other rejection operations, only candidate measurement points in the current measurement point may be determined to be non-removable. In the next rejection operation, other measurement points in the current measurement point besides the non-removable candidate measurement point can be used as new candidate measurement points to perform the rejection operation again. After completing one or a preset number of rejection operations, it can be determined whether a first preset requirement is met. If it is met, all rejection operations end, and no new rejection operations are performed. If it is not met, rejection operations continue. The first preset requirement may include that none of the current measurement points can be deleted; it may also include that the number of current measurement points meets a preset number. The first preset requirement can be set according to user needs. The process can end when the first preset requirement is met, and the measurement points other than those deleted at the end of the initial measurement points can be designated as the final measurement points. It can be understood that in the case where all rejection operations are executed sequentially, the current measurement point of the later rejection operation is the measurement point obtained after the previous rejection operation; therefore, the final measurement point is the current measurement point at the end of all rejection operations. Based on the final measurement point, overlay error measurement of the current layer of the wafer can be performed.

[0033] Figure 1 A schematic flowchart illustrating a rejection operation according to an embodiment of the present invention is shown. Figure 1 As shown, the rejection operation includes steps S1100, S1200, S1300, S1400, S1500 and S1600.

[0034] In step S1100, the first compensation residual for the current measurement point is determined. The compensation residual represents a local deviation determined based on the measurement point that cannot be covered by the global model. Its sources include local wafer stress, uneven photoresist coating, and local fluctuations in the etching process.

[0035] In a specific example, actual overlay measurements can be performed on each measurement point in the current measurement point to determine its respective overlay error measurement data. A lithography compensation model can be used to fit the measured data of each measurement point to determine the predicted overlay error data for each measurement point in the current measurement point. The aforementioned lithography compensation model can be any existing or future lithography compensation model. Optionally, a lithography compensation model adapted to the wafer's process parameters can be selected. Then, based on the overlay error measurement data and the predicted overlay error data of the current measurement point, the first compensation residual for the current measurement point can be determined. For example, the average difference between the measured overlay error and the predicted overlay error in the lateral direction of all measurement points in the current measurement point can be calculated as the first difference, and the average difference between the measured overlay error and the predicted overlay error in the longitudinal direction of all measurement points in the current measurement point can be calculated as the second difference. The first compensation residual can be calculated based on the first and second differences.

[0036] It is understandable that any existing or future research and development method can be used to determine the first compensation residual of the current measurement point.

[0037] In step S1200, selectable measurement points are determined from the current measurement points.

[0038] Candidate measurement points can include one or more measurement points from the current measurement points. Optionally, the number of candidate measurement points can be set. In a specific example, candidate measurement points can be randomly determined from the current measurement points. It can be understood that measurement points determined to be non-removable are those for which a rejection operation has been performed, but which were determined by the rejection operation to be non-removable. Therefore, in a newly performed rejection operation, candidate measurement points can be determined from measurement points other than those determined to be non-removable in the current measurement points. In an alternative example, an artificial intelligence model can be used to determine candidate measurement points from the current measurement points. The artificial intelligence model can be a model trained using wafer process parameters and historical measurement point data. Historical measurement point data can include the location data of historical measurement points and the corresponding overlay error measurement data.

[0039] In step S1300, the second compensation residual of the first remaining measurement point in the current measurement points is determined. The first remaining measurement point refers to all measurement points in the current measurement points other than the candidate measurement points. In other words, the first remaining measurement point includes all measurement points in the current measurement points other than the candidate measurement points.

[0040] In a specific example, the overlay error measurement data of each measurement point in the first remaining measurement points can be determined through actual overlay measurement. The predicted overlay error data of each measurement point in the first remaining measurement points can be determined through a lithographic compensation model. Then, based on the overlay error measurement data and the predicted overlay error data of each measurement point in the first remaining measurement points, the second compensation residual of the first remaining measurement points can be determined. The same or different lithographic compensation model as in step S1100 above can be used to determine the predicted overlay error data of each measurement point in the first remaining measurement points. The second compensation residual of the first remaining measurement points can be determined using the same or different calculation method as in step S1100 above. For example, the average difference between the measured overlay error and the predicted overlay error in the lateral direction of all measurement points in the first remaining measurement points can be calculated as the third difference. The average difference between the measured overlay error and the predicted overlay error in the longitudinal direction of all measurement points in the first remaining measurement points can be calculated as the fourth difference. The second compensation residual can be calculated based on the third and fourth differences. The second compensation residual of the first remaining measurement point can be determined using any existing or future research and development method.

[0041] In step S1400, based on the difference between the first compensated residual and the second compensated residual, the residual difference index value is calculated, wherein the larger the difference, the larger the residual difference index value.

[0042] In some embodiments, the difference between the first and second compensated residuals can be evaluated by the difference between them. A larger difference indicates a greater difference, and thus a higher residual difference index value. For example, the absolute value of the difference between the first and second compensated residuals can be calculated as the residual difference index value. In other embodiments, the difference between the first and second compensated residuals can be evaluated by the ratio of the first and second compensated residuals. The ratio of the larger of the first and second compensated residuals to the smaller of the second compensated residuals can be used as the residual difference index value; a larger ratio indicates a higher residual difference index value.

[0043] Each elimination operation can be performed by selecting either step S1500 or step S1600 based on the relationship between the residual difference index value and the first difference threshold.

[0044] In step S1500, if the residual difference index value is less than or equal to the first difference threshold, at least one candidate measurement point is deleted from the current measurement point to update the current measurement point. Step S1500 can be executed when the residual difference index value is less than or equal to the first difference threshold. In other words, when the residual difference index value is less than or equal to the first difference threshold, at least one candidate measurement point can be deleted from the current measurement point to update the current measurement point.

[0045] In some embodiments, only the candidate measurement point can be deleted from the current measurement point. In other embodiments, the candidate measurement point and its associated measurement points can be deleted from the current measurement point. For example, the candidate measurement point and all measurement points in its exposure field can be deleted from the current measurement point. It is understood that if the residual difference index value is less than or equal to a first difference threshold, it indicates that a good compensation effect can still be achieved after the candidate measurement point is deleted. The candidate measurement point can be considered a redundant measurement point. Therefore, the candidate measurement point can be deleted, thereby eliminating the need for measurement operations on the candidate measurement point and improving measurement efficiency. When the candidate measurement point is redundant, the associated measurement points, such as measurement points whose distance to it is less than a distance threshold, are also likely to be redundant. Optionally, other measurement points associated with it can be deleted at the same time as the candidate measurement point is deleted.

[0046] In step S1600, if the residual difference index value is greater than the first difference threshold, it is determined that the candidate measurement point cannot be deleted. Step S1600 is executed when the residual difference index value is greater than the first difference threshold. Therefore, it can be determined that the candidate measurement point cannot be deleted when the residual difference index value is greater than the first difference threshold.

[0047] For example, a candidate measurement point can be marked as an undeletable measurement point within the current measurement points. Optionally, in subsequent elimination operations, undeletable measurement points are not identified as candidate measurement points. In other words, the selection range of candidate measurement points is all measurement points in the current measurement points other than those already marked as undeletable. It can be understood that if the residual difference index value is greater than the first difference threshold, it indicates that deleting the candidate measurement point will not achieve a good compensation effect. Therefore, the candidate measurement point can be considered a necessary measurement point, and thus it can be identified as undeletable.

[0048] In the above technical solution, one or more elimination operations are performed until the first preset requirement is met, and the measurement points other than those deleted at the end are determined as the final measurement points. Through the elimination operation, measurement points with relatively small impact on the compensation residual are removed, i.e., measurement points whose compensation residual does not change significantly before and after deletion. Therefore, measurement points can be determined intelligently and automatically. By screening measurement points using the residual difference index value, which represents the degree of change in the compensation residual, redundant measurement points can be avoided in the final measurement points, while ensuring comprehensive coverage of the final measurement points. This improves the measurement efficiency for the final measurement points and ensures the lithographic compensation effect.

[0049] For example, the first preset requirement may include: all measurement points in the current measurement point cannot be deleted.

[0050] After performing one or more elimination operations, if all measurement points in the current measurement point are marked as non-deletable, then the first preset requirement is met, and elimination operations can be discontinued. The measurement points in the initial measurement point set, excluding those deleted at the end, are determined as the final measurement points. For example, if the current measurement point set includes 3 measurement points during the first elimination operation, and measurement point 1 is deleted, then the current measurement point set includes measurement points 2 and 3. If the second elimination operation determines that measurement point 2 is non-deletable, then the current measurement point set still includes measurement points 2 and 3, and measurement point 2 is marked as non-deletable. If the third elimination operation determines that measurement point 3 is non-deletable, then the current measurement point set still includes measurement points 2 and 3, and both measurement points 2 and 3 are marked as non-deletable. At this point, all measurement points in the current measurement point set are non-deletable, meeting the first preset requirement.

[0051] In the above technical solution, the first preset requirement includes: all measurement points in the current measurement point cannot be deleted. This ensures comprehensive measurement point coverage, better supporting the lithography compensation model, and allows the process to end promptly once all measurement points are deemed undeletable, guaranteeing the effectiveness of the removal operation.

[0052] For example, the first preset requirement may include: the current number of measurement points equals a measurement point number threshold. After each rejection operation, the current number of measurement points can be determined. If the determined number equals the measurement point number threshold, then the first preset requirement is met. For example, the measurement point number threshold is 3. If, during the first rejection operation, the current number of measurement points includes 5 points, and the first rejection operation deletes measurement point 1, the second rejection operation determines that measurement point 2 cannot be deleted, and the third rejection operation deletes measurement point 4, then the current number of measurement points is 3, which equals the measurement point number threshold and meets the first preset requirement. Users can set the measurement point number threshold as needed. For example, the measurement point number threshold can be set according to the requirements of the lithography compensation model.

[0053] In the above technical solution, the first preset requirement includes: the current number of measurement points is equal to the measurement point number threshold. This avoids deleting too many measurement points, ensures comprehensive measurement point coverage, and better supports the lithography compensation model.

[0054] For example, it can be determined at the same time whether all measurement points in the current measurement point are not deletable, and whether the number of current measurement points is equal to the measurement point number threshold. If "all measurement points in the current measurement point are not deletable" or "the number of current measurement points is equal to the measurement point number threshold", it can be determined that the first preset requirement is met.

[0055] For example, the above-mentioned elimination operation includes synchronous elimination operations, wherein the candidate measurement points determined in the synchronous elimination operations are different.

[0056] When there are a large number of measurement points on a wafer, multiple rejection operations can be performed simultaneously, with each rejection operation identifying different candidate measurement points. After one round of simultaneous rejection operations is completed, the next round of simultaneous rejection operations can identify different candidate measurement points based on the candidate measurement points identified in the previous round, and these candidate measurement points can be different from those identified in each previous round. The number of rejection operations included in each round can be the same or different. For example, in the initial execution, if there are 36 measurement points, 18 rejection operations can be performed simultaneously, with each rejection operation selecting one measurement point as a candidate measurement point. After performing 18 rejection operations simultaneously, another 18 rejection operations can be performed. By performing two consecutive rounds of simultaneous rejection operations, it is possible to determine which measurement points can be deleted and which cannot be deleted, quickly determining the final measurement points.

[0057] The above technical solution includes synchronous elimination operations, and the candidate measurement points determined in these synchronous elimination operations are different. This significantly improves the processing speed of measurement points, quickly determines the final measurement points, and enhances the ability to screen measurement points.

[0058] For example, step S1200, determining candidate measurement points from the current measurement points, includes: selecting one measurement point from the current measurement points as a candidate measurement point. For each elimination operation, one measurement point from the current measurement points can be selected as a candidate measurement point. For example, if the current measurement points include 30 measurement points, the first elimination operation can randomly select one measurement point from these 30 measurement points as a candidate measurement point to determine whether it can be deleted. Then, based on the result of the previous elimination operation, one measurement point is randomly selected from the measurement points in the current measurement points other than those that cannot be deleted as a candidate measurement point. The above elimination operation is repeated until the first preset requirement is met. It can be understood that each elimination operation can determine whether a measurement point can be deleted for only one measurement point.

[0059] In the above technical solution, only one measurement point is selected as a candidate measurement point from the current measurement points. This allows for a more precise determination of the final measurement point. It avoids the problem of simultaneously selecting multiple measurement points as candidate points, which would make it impossible to distinguish whether the selected candidate measurement points are deletable, thus requiring multiple removal operations. Therefore, it ensures the smooth and rapid determination of measurement points.

[0060] For example, a wafer may include multiple exposure fields, and measurement points may be located within these exposure fields. When a rejection operation is performed for the first time, the current measurement point includes measurement points located in different exposure fields. The exposure field in which the current measurement point is located may be part or all of the exposure fields in the wafer.

[0061] The above-mentioned process of performing one or more elimination operations until the first preset requirement is met includes: a first elimination phase of performing multiple elimination operations. In the first elimination phase, each time an elimination operation is performed, the determined candidate measurement points are located in different exposure fields, and if the residual difference index value is less than or equal to the first difference threshold, then all measurement points in the exposure field corresponding to the candidate measurement point are deleted from the current measurement point to update the current measurement point.

[0062] The first rejection phase may include performing at least one rejection operation. During the rejection phase, the candidate measurement points determined in step S1200 for each rejection operation are located in different exposure fields. In some embodiments, the current measurement points at the time of the first rejection operation are located in 10 exposure fields. One measurement point can be determined from each of these 10 exposure fields, resulting in 10 measurement points. During the rejection phase, one measurement point can be selected as a candidate measurement point from these 10 measurement points. Since these 10 measurement points are located in different exposure fields, it ensures that the candidate measurement point determined during each rejection operation in the first rejection phase is located in a different exposure field. In other embodiments, when determining candidate measurement points during the rejection phase, any one or more measurement points in a different exposure field can be determined as candidate measurement points for the current rejection operation, based on the exposure field corresponding to the candidate measurement point determined in the previous rejection operations in the first rejection phase. For example, during the initial rejection operation, the current measurement point is located in three exposure fields: exposure field 1, exposure field 2, and exposure field 3. In the first rejection phase, during the initial rejection operation, a candidate measurement point can be determined in any of the three exposure fields, for example, in exposure field 1. During the second rejection operation, a candidate measurement point can be determined in either exposure field 2 or exposure field 3.

[0063] During the first elimination phase, if the residual difference index value is less than or equal to the first difference threshold, all measurement points in the exposure field corresponding to the candidate measurement point are deleted from the current measurement point to update the current measurement point. Alternatively, if the residual difference index value is less than or equal to the first difference threshold during the first elimination phase, all measurement points in the exposure field of the candidate measurement point determined in this elimination operation can be identified as redundant measurement points. In this case, all measurement points in the exposure field corresponding to the candidate measurement point can be deleted from the current measurement point to update the current measurement point.

[0064] If the above-mentioned elimination operation is performed once or multiple times until the first preset requirement is met, and only the first elimination stage is included, the final measurement point can be determined based on all the measurement points deleted at the end of the first elimination stage.

[0065] In the above technical solution, during the first elimination stage, each time an elimination operation is performed, the determined candidate measurement points are located in different exposure fields. If the residual difference index value is less than or equal to the first difference threshold, all measurement points in the exposure field corresponding to the candidate measurement point are deleted from the current measurement point to update the current measurement point. This speeds up the elimination operation, reduces the number of elimination operations, and quickly determines the final measurement point.

[0066] For example, in the first elimination stage, each time an elimination operation is performed, the candidate measurement point is determined to be a measurement point located in the central region of the exposure field.

[0067] In the first elimination phase, the elimination operation determines candidate measurement points located in different exposure fields for each elimination operation. In some embodiments, the current measurement points at the time of the first elimination operation are located in 10 exposure fields. For each of the 10 exposure fields, a measurement point in the central region of each exposure field can be determined, resulting in 10 measurement points. One measurement point can be selected as a candidate measurement point from these 10 measurement points. These 10 measurement points are located in the central region of different exposure fields. It can be understood that the central region of an exposure field can be an area within a preset distance range from the center point of the exposure field. Optionally, the measurement point closest to the center point in each exposure field can be determined as a measurement point located in the central region of that exposure field. In other embodiments, the exposure fields where the current measurement points are located can be determined. When performing a rejection operation to determine candidate measurement points, a measurement point located in the central region of an exposure field different from the one determined in the previous rejection operation in the first rejection stage can be selected as a candidate measurement point for this rejection operation. For example, the current measurement points are located in three exposure fields, namely exposure field 1, exposure field 2, and exposure field 3. In the first rejection stage, when performing the first rejection operation, a measurement point can be determined as a candidate measurement point in the central region of any one of the three exposure fields, for example, in the central region of exposure field 1. When performing the second rejection operation, a measurement point can be determined as a candidate measurement point in the central region of any one of the exposure fields, exposure field 2 or exposure field 3.

[0068] In the above technical solution, during the first rejection stage, the candidate measurement point determined each time a rejection operation is performed is a measurement point located in the central region of the exposure field. Therefore, since the measurement point in the central region of the exposure field is least affected by factors such as edge diffraction and adjacent field interference, it can better represent the overall characteristics of the exposure field. Selecting a measurement point in the central region as a candidate measurement point helps avoid mistakenly deleting key measurement points during the first rejection stage, ensuring the accuracy of the final measurement point.

[0069] For example, the above-described process of performing one or more rejection operations until a first preset requirement is met further includes a second rejection stage that performs multiple sets of rejection operations. When the second preset requirement is met, the process transitions from the first rejection stage to the second rejection stage. Each set of rejection operations in the second rejection stage includes at least one consecutive rejection operation. The candidate measurement points determined in at least one rejection operation within each set of rejection operations are located within the same exposure field, and the candidate measurement points determined in different sets of rejection operations are located within different exposure fields.

[0070] When the second preset requirement is met, the first elimination stage can end and the second elimination stage can begin. The second preset requirement may include that the current number of measurement points is less than or equal to a measurement point number threshold. The second preset requirement may also include that the number of times the elimination operation is executed in the first elimination stage is equal to the first threshold. The second preset requirement may further include that the number of times the action "delete all measurement points in the exposure field corresponding to the candidate measurement point at the current measurement point" is executed is equal to the second threshold. Users can set any form of second preset requirement as needed.

[0071] The second culling phase can include multiple sets of culling operations. Each set of culling operations can include at least one culling operation executed consecutively. These multiple sets of culling operations can be executed in parallel or sequentially. Parallel execution means that multiple sets of culling operations can be executed simultaneously. Sequential execution means that the next set of culling operations can only begin execution after the previous set has been completed. Users can configure the multiple sets of culling operations to be executed sequentially or in parallel as needed.

[0072] For example, at the end of the first elimination stage, the number of elimination operations in the second elimination stage can be determined based on the number of exposure fields where the current measurement points are located at the end of the first elimination stage. Thus, multiple elimination operations can correspond one-to-one with the exposure fields where the current measurement points are located at the end of the first elimination stage. When executing at least one elimination operation in each group of elimination operations, the candidate measurement points determined in step S1200 of different groups of elimination operations are located in different exposure fields. In each group of elimination operations, candidate measurement points can be determined in the exposure field corresponding to that group of elimination operations; that is, when step S1200 is executed in that group of elimination operations, the candidate measurement points determined are all located in the exposure field corresponding to that group of elimination operations. Therefore, measurement points within the exposure fields can be filtered and deleted. For example, at the end of the first elimination stage, the current measurement points are located in three exposure fields, namely exposure field 1, exposure field 2, and exposure field 3. The second elimination stage may include three groups of elimination operations. The first set of rejection operations can be performed on measurement points in exposure field 1. When performing the first set of rejection operations, candidate measurement points can be determined only from the measurement points in exposure field 1. Similarly, the second set of rejection operations can be performed on measurement points in exposure field 2, and the third set of rejection operations can be performed on measurement points in exposure field 3. After all sets of rejection operations are completed, the final measurement point is determined. This final measurement point is the remaining measurement point after deleting the candidate measurement points deleted by each set of rejection operations from the current measurement point at the end of the first rejection stage. In other words, when the final measurement point is determined in accordance with the first preset requirement, all deleted measurement points include the measurement points deleted in the first rejection stage and the measurement points deleted by each set of rejection operations in the second rejection stage.

[0073] In the above technical solution, the method for determining measurement points includes the first rejection stage and the second rejection stage. When a second preset requirement is met, the process transitions from the first rejection stage to the second rejection stage. The second rejection stage includes multiple sets of rejection operations. Each set of rejection operations includes at least one consecutive rejection operation. The candidate measurement points determined in at least one rejection operation within each set are located within the same exposure field, and the candidate measurement points determined in different sets of rejection operations are located within different exposure fields. Therefore, in the exposure fields containing the remaining measurement points from the first rejection stage, measurement points within each exposure field can be screened and deleted separately. This allows for the precise removal of redundant measurement points while retaining necessary ones, improving the accuracy of the final measurement points. Furthermore, multiple sets of rejection operations can be executed serially, saving computational resources, or in parallel, accelerating processing speed.

[0074] For example, at least one set of rejection operations includes multiple steps executed sequentially. In at least one of the multiple steps, at least two rejection operations are executed concurrently, and the candidate measurement points determined in the concurrently executed rejection operations are different. At least one set of rejection operations constitutes multiple operation flows. Each operation flow includes at least one first rejection operation. Each first rejection operation is executed in one step of the multiple steps. In each operation flow that also includes a second rejection operation, the current measurement point when the second rejection operation is executed is the measurement point obtained after the candidate measurement point was deleted in the first rejection operation. The first rejection operation and the second rejection operation are rejection operations executed in two sequentially executed steps within the same operation flow.

[0075] Figure 2 A schematic diagram illustrating the steps and operation flow of a set of rejection operations according to an embodiment of the present invention is shown. This set of rejection operations is performed on a measurement point within an exposure field of a wafer. Figure 2 As shown, this set of elimination operations includes four steps executed sequentially: Step 1, Step 2, Step 3, and Step 4. Step 1 includes elimination operations 11, 21, and 31; Step 2 includes elimination operations 12, 22, and 32; Step 3 includes elimination operations 13, 23, and 33; and Step 4 includes elimination operations 14, 24, and 34. It is understood that the number of elimination operations included in each step can be the same or different. When the number is equal, computational resources are utilized more effectively. Elimination operations 11, 21, and 31 in Step 1 can be executed synchronously. The elimination operations included in Step 1 are the first elimination operations executed in this set of elimination operations. Candidate measurement points can be determined from the measurement points in the exposure field targeted by this set of elimination operations. The candidate measurement points determined in the synchronously executed rejection operations can be different; that is, the candidate measurement points determined in rejection operations 11, 21, and 31 are different. Since different rejection operations in the same step can belong to different operation flows, different point selection strategies can be adopted in the rejection operations in different operation flows, so that the candidate measurement points determined by different rejection operations in the same step are different. After the synchronously executed rejection operations corresponding to step 1 (i.e., rejection operations 11, 21, and 31) are completed, the rejection operations corresponding to step 2 (i.e., rejection operations 12, 22, and 32) can be executed.

[0076] Figure 2This group of rejection operations can form 5 operation flows. Rejection operations 11 and 12 correspond to operation flow 1. Rejection operations 21, 22, 13, and 14 correspond to operation flow 2. Rejection operations 21, 22, 13, and 24 correspond to operation flow 3. Rejection operations 21, 22, and 23 correspond to operation flow 4. Rejection operations 31, 32, 33, and 34 correspond to operation flow 5. Different operation flows may include the same rejection operations. For example, operation flows 2 and 3 both include rejection operations 21, 22, and 13. It can be understood that each operation flow may include at least one rejection operation. If it is determined that the candidate measurement point identified by a rejection operation in an operation flow cannot be deleted, the execution of that operation flow can be stopped. If a rejection operation in an operation flow deletes at least one candidate measurement point determined by the rejection operation at the current measurement point, then the next rejection operation in the operation flow can be executed. Taking operation flow 1 as an example, rejection operation 11 can delete the candidate measurement point determined by rejection operation 11 at the current measurement point. Rejection operation 12 can determine that the candidate measurement point determined by rejection operation 12 cannot be deleted, and the execution of operation flow 1 can be stopped. The current measurement point when rejection operation 12 is executed can be the measurement point obtained after the candidate measurement point determined by rejection operation 11 is deleted, that is, rejection operation 11 can be the first rejection operation, and rejection operation 12 can be the second rejection operation. It can be understood that the operation flows corresponding to rejection operations 21 and 22 can be split into two operation flows in step 3. Rejection operations 22 and 13 belong to the same operation flow and are rejection operations executed sequentially in steps 2 and 3, respectively. The current measurement point when removal operation 13 is executed can be the measurement point obtained after removing the candidate measurement points determined by removal operation 22. Similarly, removal operations 22 and 23 also belong to the same operation flow and are removal operations executed sequentially in steps 2 and 3, respectively. The current measurement point when removal operation 23 is executed can be the measurement point obtained after removing the candidate measurement points determined by removal operation 22. It can be understood that the operation flows corresponding to removal operations 21, 22, and 13 can be split into two operation flows in step 4. In other words, an operation flow can be split into multiple operation flows as needed. Optionally, if an operation flow stops executing in the previous step, any unstopped operation flow can be automatically split in the next step. This ensures that the number of removal operations executed in each step is the same.

[0077] When the third preset requirement is met, the execution of multiple steps can be terminated. The third preset requirement may include that the number of measurement points determined by the group of rejection operations is less than or equal to a preset number. The third preset requirement may also include that the number of times the rejection operations are executed in the multiple steps reaches a preset number. The measurement points determined by the group of rejection operations can be obtained based on the union of the measurement points deleted in each operation flow. For example, the measurement points corresponding to the union of the above-mentioned measurement points can be deleted from all measurement points in the exposure field corresponding to the group of rejection operations to obtain the measurement points determined by the group of rejection operations. (Continuing with...) Figure 2 For example, step 4 can be the last step executed, which can determine the union of all deleted measurement points after the execution of elimination operations 12, 14, 24 and 34. For example, the exposure field corresponding to this group of elimination operations includes 20 measurement points. Elimination operation 11 deleted measurement point 2, elimination operation 14 deleted measurement points 1, 7, 10 and 15, elimination operation 24 deleted measurement points 1, 7, 10 and 8, and elimination operation 33 deleted measurement points 3, 6, 5 and 9. The union of the deleted measurement points includes measurement points 1, 2, 3, 5, 6, 7, 8, 9, 10 and 15. The measurement points determined by this group of elimination operations include measurement points 4, 11, 12, 13, 14, 16, 17, 18, 19 and 20.

[0078] In the above technical solution, at least two rejection operations are executed simultaneously in at least one of the multiple steps, and the candidate measurement points determined in the synchronously executed rejection operations are different; at least one set of rejection operations constitutes multiple operation flows, and in some operation flows, the current measurement point when executing the second rejection operation is the measurement point obtained after deleting the candidate measurement point in the first rejection operation. The first rejection operation and the second rejection operation are rejection operations executed in two sequential steps within the same operation flow. In the above technical solution, the rejection operation is executed by multiple synchronous operation flows, and different operation flows can adopt different point selection strategies to fully and comprehensively select measurement points, ensuring comprehensive point selection coverage and reducing redundancy; moreover, the execution speed is fast, and the efficiency of determining measurement points is significantly improved.

[0079] For example, as described above, when the second preset requirement is met, the process transitions from the first rejection stage to the second rejection stage. In the first rejection stage, each rejection operation involves determining candidate measurement points located at different exposure fields, and each measurement point is deleted on a per-exposure-field basis. In the second rejection stage, only the determined candidate measurement points can be deleted in each rejection operation.

[0080] For example, the second preset requirement may include: the number of exposure fields in which the deleted measurement points are located is equal to the deletion field number threshold. In the first elimination stage, after each elimination operation, the number of exposure fields in which the currently deleted measurement points are located can be determined. If the number is equal to the deletion field number threshold, then the second preset requirement is met, and the first elimination stage can end. For example, if the deletion field number threshold is 2, and the first elimination operation in the first elimination stage occurs when the current measurement points are located in 5 exposure fields, the first elimination operation deletes all measurement points corresponding to exposure field 1, the second elimination operation does not delete any measurement points, and the third elimination operation deletes all measurement points corresponding to exposure field 3. That is, the number of exposure fields in which the deleted measurement points are located is 2, which is equal to the deletion field number threshold. Therefore, the second preset requirement is met, and the first elimination stage can end. Users can set the deletion field number threshold as needed. For example, the deletion field number threshold can be set according to the requirements of the lithography compensation model.

[0081] In the above technical solution, the second preset requirement includes: the number of exposure fields containing the deleted measurement points is equal to the deletion field number threshold. Therefore, a deletion field number threshold can be set to avoid insufficient remaining exposure fields leading to incomplete measurement point coverage, thus better supporting the lithography compensation model.

[0082] For example, the second preset requirement may include that the rejection operation in the first rejection stage has traversed all exposure fields. If all exposure fields have been traversed, the first rejection stage can be terminated. For instance, when the first rejection stage is executed for the first time, the current measurement point is located in three exposure fields. The first rejection operation identifies candidate measurement points in exposure field 1, the second rejection operation identifies candidate measurement points in exposure field 2, and the third rejection operation identifies candidate measurement points in exposure field 3. Since all three exposure fields have been traversed, the second preset requirement is met, and the first rejection stage can be terminated.

[0083] In the above technical solution, the second preset requirement includes that the rejection operation in the first rejection stage has traversed all exposure fields. The process can be terminated promptly after the traversal is complete to ensure the effectiveness of the first rejection stage.

[0084] For example, it can be determined at the same time whether the number of exposure fields where the deleted measurement points are located is equal to the deletion field number threshold, and whether the elimination operation in the first elimination stage has traversed all exposure fields. If "the number of exposure fields where the deleted measurement points are located is equal to the deletion field number threshold" or "the elimination operation in the first elimination stage has traversed all exposure fields", it can be determined that the second preset requirement is met.

[0085] By way of example, according to another aspect of the present invention, an electronic device is also provided. Figure 3A schematic block diagram of an electronic device 300 according to an embodiment of the present invention is shown. The electronic device 300 includes a processor 310 and a memory 320. The memory 320 stores computer program instructions, which, when executed by the processor 310, are used to perform the method for determining measurement points on a wafer as described above.

[0086] By way of example, according to another aspect of the present invention, a storage medium is also provided, on which program instructions are stored, which, when executed, are used to perform the method for determining measurement points of a wafer as described above. The storage medium may, for example, include an erasable programmable read-only memory (EPROM), a portable read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The storage medium may be any combination of one or more computer-readable storage media.

[0087] By way of example, according to another aspect of the present invention, a computer program product is also provided, including computer program instructions, which, when executed, are used to perform the method for determining measurement points of a wafer as described above.

[0088] Those skilled in the art can understand the specific implementation schemes and beneficial effects of the above-mentioned electronic devices, storage media, and computer program products by reading the relevant descriptions of the methods for determining measurement points on wafers. For the sake of brevity, they will not be elaborated further here.

[0089] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0090] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0091] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0092] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0093] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0094] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0095] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0096] This application can also be implemented as an apparatus program (e.g., a computer program and a computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium or can take the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0097] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer.

[0098] The above description is merely a specific embodiment or illustration of the embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A method for determining measurement points on a wafer, characterized in that, include: One or more rejection operations are performed on the initial measurement points of the wafer until a first preset requirement is met. The measurement points other than all the measurement points deleted at the end of the initial measurement point period are determined as the final measurement points. The removal operation includes: Determine the first compensation residual for the current measurement point; Determine candidate measurement points from the current measurement points; Determine the second compensation residual of the first remaining measurement point in the current measurement points, wherein the first remaining measurement point is another measurement point other than the candidate measurement point in the current measurement points; Based on the difference between the first compensation residual and the second compensation residual, a residual difference index value is calculated, wherein the larger the difference, the larger the residual difference index value. If the residual difference index value is less than or equal to the first difference threshold, then at least the candidate measurement points are deleted from the current measurement points to update the current measurement points; If the residual difference index value is greater than the first difference threshold, then the candidate measurement point is determined to be non-deletable.

2. The method for determining measurement points on a wafer according to claim 1, characterized in that, When the rejection operation is performed for the first time, the current measurement points include measurement points located in different exposure fields. The process of performing one or more rejection operations until the first preset requirement is met includes: a first rejection phase of performing multiple rejection operations; In the first elimination stage, each time the elimination operation is performed, the determined candidate measurement points are located in different exposure fields, and if the residual difference index value is less than or equal to the first difference threshold, then all measurement points in the exposure field corresponding to the candidate measurement point are deleted in the current measurement point to update the current measurement point.

3. The method for determining measurement points on a wafer according to claim 2, characterized in that, In the first elimination phase, each time an elimination operation is performed, the candidate measurement point is determined to be a measurement point located in the central region of the exposure field.

4. The method for determining measurement points on a wafer according to claim 2, characterized in that, The process of performing one or more elimination operations until the first preset requirement is met also includes a second elimination stage of performing multiple sets of elimination operations. When the second preset requirement is met, the process transitions from the first rejection stage to the second rejection stage. Each rejection operation includes at least one rejection operation executed consecutively. The candidate measurement points determined in each rejection operation are located within the same exposure field, and the candidate measurement points determined in different rejection operations are located within different exposure fields.

5. The method for determining measurement points on a wafer according to claim 4, characterized in that, At least one set of rejection operations includes multiple steps executed sequentially. In at least one of the multiple steps, at least two rejection operations are performed simultaneously, and the candidate measurement points determined in the simultaneous rejection operations are different. The at least one set of rejection operations constitutes multiple operation flows, each operation flow includes at least one first rejection operation, each first rejection operation is executed in one of the multiple steps, and in each operation flow that also includes a second rejection operation, the current measurement point when the second rejection operation is executed is the measurement point obtained after the candidate measurement point is deleted in the first rejection operation. The first rejection operation and the second rejection operation are rejection operations executed in two steps that are executed sequentially in the multiple steps within the same operation flow.

6. The method for determining measurement points on a wafer according to claim 4, characterized in that, The second preset requirement includes: the number of exposure fields in which the deleted measurement points are located is equal to the threshold number of deleted fields, and / or the deletion operation in the first deletion stage has traversed all exposure fields.

7. The method for determining measurement points on a wafer according to claim 1, characterized in that, The first preset requirement includes: all measurement points in the current measurement point cannot be deleted, and / or the number of current measurement points is equal to the measurement point number threshold.

8. The method for determining measurement points on a wafer according to claim 1, characterized in that, The elimination operation includes synchronous elimination operations, in which different candidate measurement points are determined in the synchronous elimination operations.

9. The method for determining measurement points on a wafer according to claim 1, characterized in that, The step of determining the candidate measurement point among the current measurement points includes: determining one measurement point among the current measurement points as the candidate measurement point.

10. An electronic device, comprising: Processor and memory, characterized in that, The memory stores computer program instructions, which, when executed by the processor, are used to perform the method for determining measurement points on a wafer as described in any one of claims 1 to 9.

11. A storage medium on which program instructions are stored, characterized in that, The program instructions, when executed, are used to perform the method for determining measurement points on a wafer as described in any one of claims 1 to 9.

12. A computer program product comprising computer program instructions, characterized in that, The computer program instructions, when executed, are used to perform the method for determining measurement points on a wafer as described in any one of claims 1 to 9.

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