Overlay mark manufacturability fast screening method, device and computer equipment

Abstract

The application relates to the field of photoetching technology, and particularly relates to a method and device for rapidly screening overlay mark manufacturability and computer equipment, which comprises the following steps: inputting preset range of process window conditions, selecting upper limit value and lower limit value as extreme process window conditions; calculating initial process variation bandwidth value based on the extreme process window conditions, and performing first screening on the initial process variation bandwidth value based on a preset screening ratio; calculating to-be-processed process window values corresponding to the screened process variation bandwidth values; performing second screening on the to-be-processed process window values based on a preset standard range to obtain final process window values; and screening the overlay marks corresponding to the final process window values. The application further provides a device and computer equipment. The problems of time and labor consumption in screening overlay mark manufacturability are solved.

Description

Technical Field

[0001] This invention relates to the field of photolithography, and particularly to a method, apparatus, and computer equipment for rapid screening of the manufacturability of overlay markings. Background Technology

[0002] With the development of the semiconductor industry, the requirements for integrated circuit manufacturing processes are becoming increasingly stringent. Among these requirements, the measurement of overlay error in integrated circuit manufacturing is an indicator of the alignment quality of the photolithography process. Overlay error refers to the deviation caused by the misalignment of patterns between layers on a wafer during integrated circuit manufacturing. It is indirectly measured by measuring the overlay marks. The overall performance of the overlay marks can be evaluated through their manufacturability.

[0003] In existing designs, the manufacturability of overlay marks is determined by calculating and analyzing the focus value range in the photolithography process. Users can select corresponding parameters based on the results to ensure that the final overlay marks have good process windows and photolithographic imaging quality. However, for large-scale overlay mark screening, this means a large number of process window value calculations, and process window value analysis itself is a time-consuming and complex calculation. Therefore, it is particularly important to achieve rapid screening and analysis of overlay mark manufacturability. Summary of the Invention

[0004] To address the time-consuming and labor-intensive problem of screening the manufacturability of overlay marks in existing technologies, this invention provides a method, apparatus, and computer equipment for rapid screening of the manufacturability of overlay marks.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for rapid screening of manufacturability of overlay markings, comprising the following steps:

[0006] Input the process window conditions within a preset range, and select the upper and lower limits as extreme process window conditions;

[0007] The initial process variation bandwidth value is calculated based on extreme process window conditions, and the initial process variation bandwidth value is first filtered based on a preset screening ratio.

[0008] The process window value to be processed is calculated by the overlay mark corresponding to the selected process variation bandwidth value;

[0009] The final process window value is obtained by performing a second screening based on a preset standard range of process window values;

[0010] Filter out the overlay marks corresponding to the final process window value.

[0011] Preferably, the initial process variation bandwidth value is calculated based on extreme process window conditions, and the initial process variation bandwidth value is first screened based on a preset screening ratio, including the following steps:

[0012] Based on extreme process window conditions, the first quantity of process variation bandwidth values ​​is obtained by calculating the overlay marks using a preset model;

[0013] Based on a preset screening ratio, a first quantity of process variation bandwidth values ​​are screened to obtain a second quantity of process variation bandwidth values, wherein the second quantity is less than the first quantity.

[0014] Preferably, the process window conditions include the focus value and the light dose value.

[0015] Preferably, the range of the focus value variable is -150~150nm, and the range of the light dose value variable is -0.1~0.1.

[0016] Preferably, the first screening of process variation bandwidth values ​​based on a preset accuracy range includes the following steps: calculating the overlay marks using a preset model based on extreme process window conditions to obtain a first number of process variation bandwidth values, and further includes the following steps: performing a first time calculation based on the OPC model to obtain a first number of process variation bandwidth values.

[0017] Preferably, the difference between the first quantity and the second quantity is set as the third quantity; the time required to obtain the process window value by calculating the overlay mark corresponding to the third quantity of process change bandwidth value through a preset model based on the process window conditions within a preset range is the second time, and the ratio of the first time to the second time is a preset screening ratio; the ratio of the first time to the second time is less than 1.

[0018] Preferably, the process window value to be processed is calculated by the overlay mark corresponding to the screened process variation bandwidth value, which includes the following steps: the overlay mark corresponding to the screened process variation bandwidth value is calculated based on the process window conditions within a preset range to obtain the process window value to be processed.

[0019] Preferably, the preset standard is a focusing depth; the preset standard range is 200-300nm.

[0020] To solve the above-mentioned technical problems, the present invention provides another technical solution as follows: an apparatus for rapid screening of manufacturability of the above-mentioned overlay marking method, the apparatus comprising:

[0021] Calculation module: Calculates the initial process variation bandwidth value based on extreme process window conditions;

[0022] Input module: Used to input process window conditions within a preset range;

[0023] Selection module: used to perform a first screening of the initial process variation bandwidth value based on a preset screening ratio, or to perform a second screening of the process window value to be processed based on a preset standard range to obtain the final process window value.

[0024] To solve the above-mentioned technical problems, the present invention provides another technical solution as follows: a computer device applied to the above-mentioned rapid screening method for manufacturability of overlay marks, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the above-mentioned computer program to implement the steps of the rapid screening method for manufacturability of overlay marks.

[0025] Compared with the prior art, the rapid screening method, apparatus, and computer equipment for manufacturability of overlay marking provided by the present invention have the following beneficial effects:

[0026] 1. This invention provides a rapid screening method for the manufacturability of overlay marks, comprising the following steps: inputting process window conditions within a preset range, and selecting the upper and lower limits as extreme process window conditions; calculating an initial process variation bandwidth value based on the extreme process window conditions, and performing a first screening on the initial process variation bandwidth value based on a preset screening ratio; calculating a process window value to be processed for the overlay marks corresponding to the screened process variation bandwidth values; performing a second screening on the process window values ​​to be processed based on a preset standard range to obtain a final process window value; and screening out the overlay marks corresponding to the final process window value. The rapid screening method for manufacturability of overlay marks provided in this embodiment employs a two-step screening approach. It selects upper and lower limits within a preset range as extreme process window conditions. The extreme process conditions are used to calculate the process variation bandwidth value corresponding to the overlay mark. The time required to calculate the process variation bandwidth value of the overlay mark using the preset model is significantly less than the time required to directly calculate the process window value corresponding to the overlay mark, greatly reducing the time spent on the first screening. Then, the overlay marks corresponding to the screened process bandwidth values ​​are calculated to obtain the process window value to be processed. Finally, the process window value to be processed is screened a second time to obtain a process window value that meets the preset standards, resulting in high screening efficiency.

[0027] 2. The embodiment of this invention calculates an initial process variation bandwidth value based on extreme process window conditions. The first screening of this initial process variation bandwidth value based on a preset screening ratio includes the following steps: calculating a first number of process variation bandwidth values ​​for the overlay marks using a preset model based on extreme process window conditions; and performing a first screening on the first number of process variation bandwidth values ​​based on the preset screening ratio to obtain a second number of process variation bandwidth values, where the second number is less than the first number. By analyzing the process variation bandwidth values ​​of overlay marks that take less time to calculate, overlay marks with poor manufacturability are eliminated, reducing the number of complex calculation iterations of the process window value under all exposure process window condition variables, thus saving computing resources and time costs for software users.

[0028] 3. The process window conditions in this embodiment of the invention include a focus value and a light dose value. The focus value ranges from -150 to 150 nm, and the light dose value ranges from -0.1 to 0.1. By setting the ranges of the focus value and light dose value, users can quickly select extreme process window conditions and analyze overlay marks through preset process window condition ranges, thereby quickly eliminating overlay marks with poor manufacturability.

[0029] 4. The embodiment of the present invention, which calculates the first number of process variation bandwidth values ​​for overlay marks based on extreme process window conditions using a preset model, further includes the following step: calculating the first number of process variation bandwidth values ​​in a first time based on the OPC model. Obtaining the first number of process variation bandwidth values ​​through this first-time calculation is faster than the prior art which directly calculates the process window values.

[0030] 5. In this embodiment of the invention, the difference between the first quantity and the second quantity is set as the third quantity; the time required to calculate the process window value of the overlay mark corresponding to the third quantity of process variation bandwidth values ​​based on the process window conditions within a preset range is the second time, and the ratio of the first time to the second time is the preset screening ratio. By setting the preset screening ratio, the process variation bandwidth values ​​of the first quantity of overlay marks are first screened to remove process bandwidth values ​​that do not meet the requirements, so as to achieve the purpose of rapid screening.

[0031] 6. In this embodiment of the invention, the ratio of the first time to the second time is less than 1. That is, the time spent calculating the process variation bandwidth value by first performing extreme process window conditions, filtering the overlay marks, and then calculating the process window value of the filtered overlay marks is less than the time spent directly calculating the process window value of all overlay marks and then filtering out process window values ​​that do not meet the standard. This achieves the purpose of rapid filtering.

[0032] 7. The preset standard in this embodiment of the invention is the focusing depth; the preset standard ranges from 200 to 300 nm. Based on the preset standard, the process window value to be processed can be quickly filtered to obtain the final process window value required by the user. The method is convenient and efficient.

[0033] 8. This invention also provides an apparatus that has the same beneficial effects as the above-described method for rapid screening of manufacturability of overlay markings, which will not be described in detail here.

[0034] 9. The present invention also provides a computer device that has the same beneficial effects as the above-described method for rapid screening of manufacturability of overlay markings, which will not be described in detail here. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a rapid screening method for manufacturability of overlay marking provided in an embodiment of the present invention.

[0036] Figure 2 This is a partial flowchart of a rapid screening method for manufacturability of overlay marking provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the overlay marking structure. Figure 1 .

[0038] Figure 4 This is a schematic diagram of the overlay marking structure. Figure 2 .

[0039] Figure 5 This is a schematic diagram of a device structure provided in an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of a computer device structure provided in an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached diagram:

[0042] 1. Device; 2. Computer equipment;

[0043] 11. Calculation module; 12. Input module; 13. Selection module; 14. Storage module; 21. Memory; 22. Processor; 23. Computer program. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] In the embodiments provided by this invention, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.

[0046] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to the invention.

[0047] In various embodiments of the present invention, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0048] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. It is particularly important to note that each block in the block diagrams and flowcharts, and combinations of blocks in the block diagrams and flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0049] In existing designs, rapid measurement and accurate evaluation of overlay error are crucial for optimizing lithography machine operating parameters and managing process yield. Overlay error refers to the deviation caused by the misalignment of patterns between layers on a wafer during integrated circuit manufacturing. Overlay error can be indirectly measured through overlay marks. The overall performance of overlay marks can be evaluated through their manufacturability. Manufacturability of overlay marks is obtained by calculating and analyzing the focus range or illumination dose range in the lithography process to obtain the corresponding process window value (pw). Users then screen overlay marks based on the obtained process window value to ensure that the final overlay marks have good process window and lithographic imaging quality. However, for large-scale overlay mark screening, existing technologies directly calculate the process window value of the overlay marks, which is time-consuming.

[0050] Please see Figure 1 This invention provides a method for rapid screening of manufacturability of overlay markings, comprising the following steps:

[0051] S1, Input the process window conditions within the preset range, and select the upper and lower limits as extreme process window conditions;

[0052] S2, calculate the initial process variation bandwidth value based on extreme process window conditions, and perform a first screening on the initial process variation bandwidth value based on a preset screening ratio;

[0053] S3, calculate the process window value to be processed by the overlay mark corresponding to the selected process change bandwidth value;

[0054] S4, based on the preset standard range, perform a second screening of the process window value to be processed to obtain the final process window value;

[0055] S5, filter out the overlay marks corresponding to the final process window value.

[0056] Understandably, the process variation bandwidth value is the difference between the extreme values ​​of the fitted critical linewidth obtained after exposure under different process window conditions. Please refer to [further details to be added]. Figure 2 , Figure 2A BasicLS-shaped overlay mark is provided, where the critical dimension (CD) refers to the linewidth of the overlay mark, and the distance of one period (PITCH) refers to the distance between adjacent critical dimensions in the BasicLS shape formed by iterative overlays of adjacent critical dimensions. The fitted critical linewidth value can be obtained by fitting a preset model. For example, if the light used in lithography is 193nm, and the critical dimension (CD) value of the overlay mark is designed to be 200nm, which is very close to the wavelength of light, the light passing through the overlay mark will produce an image close to the BasicLS shape. However, due to the optical proximity effect when light passes through the overlay mark, the critical dimension (CD) value in the image displayed after the light passes through the overlay mark may increase or decrease. Fitting is performed using a preset model, specifically an OPC model. Different process window conditions are input into the model, and after exposure, the critical dimension (CD) value in the image displayed after passing through the overlay mark is the fitted value. The difference between the maximum and minimum values ​​of the fitted values ​​is the process variation bandwidth value. Different process variation bandwidth values ​​can be obtained by substituting different process window conditions into a preset model. The method is simple, and a larger process variation bandwidth value indicates a worse manufacturability of the corresponding overlay mark. In addition, under process window conditions, the time spent calculating the process variation bandwidth value of the overlay mark through the preset model is much less than the time spent directly calculating the process window value corresponding to the overlay mark.

[0057] It should be understood that this embodiment employs a two-step screening method. It selects the upper and lower limits within a preset range as extreme process window conditions. The extreme process conditions are used to calculate the process variation bandwidth value corresponding to the overlay mark. Because the time required for the preset model to calculate the process variation bandwidth value of the overlay mark is much less than the time required to directly calculate the process window value corresponding to the overlay mark, the time spent on the first screening is significantly reduced. Then, the overlay mark corresponding to the screened process bandwidth value is calculated to obtain the process window value to be processed. Finally, the process window value to be processed is screened a second time to obtain the final process window value that meets the preset standard, resulting in high screening efficiency.

[0058] Please combine Figure 1 and Figure 2 In step S2 above, the initial process variation bandwidth value is calculated based on extreme process window conditions, and the initial process variation bandwidth value is first screened based on a preset screening ratio, including the following steps:

[0059] S21, Based on extreme process window conditions, the first quantity of process variation bandwidth value is obtained by calculating the overlay mark using a preset model;

[0060] S22, perform a first screening on the first quantity of process change bandwidth values ​​based on a preset screening ratio to obtain a second quantity of process change bandwidth values, wherein the second quantity is less than the first quantity.

[0061] In step S3 above, the calculation of the overlay mark corresponding to the screened process variation bandwidth value to obtain the process window value to be processed includes the following steps: Calculate the overlay mark corresponding to the screened process variation bandwidth value based on the process window conditions within a preset range to obtain the process window value to be processed.

[0062] It should be understood that this embodiment first selects the upper and lower limits of a preset range as extreme process window conditions, and then calculates the process variation bandwidth value corresponding to all overlay marks under the extreme process window conditions, i.e., the first number of process variation bandwidth values. It should be noted that the relationship between all overlay marks and the first number of process variation bandwidth values ​​is one-to-one. For example, now it is necessary to analyze the manufacturability of 3000 overlay marks. The number of extreme process window conditions selected is 4. Each overlay mark can obtain 4 fitted key dimension values ​​under the extreme process window conditions, and the difference between the maximum and minimum values ​​among the fitted values ​​is the process variation bandwidth value. That is, 3000 process bandwidth values ​​can be obtained by calculating 3000 overlay marks under the extreme process window conditions. Next, this embodiment performs a first screening on the first number of process variation bandwidth values ​​based on a preset screening ratio, filtering out some process variation bandwidth values ​​that do not meet the preset screening ratio requirements to obtain a second number of process variation bandwidth values. Finally, based on the process window conditions within a preset range, the overlay marks corresponding to the second number of process variation bandwidth values ​​are calculated to obtain the process window value. That is, the rapid screening method for manufacturability of overlay marks provided in this embodiment eliminates overlay marks with poor manufacturability by analyzing and calculating the process variation bandwidth values ​​of overlay marks with short calculation time, reducing the number of complex calculation iterations of process window values ​​under all exposure process window condition variables, and saving computing resources and time costs for software users.

[0063] Before step S1 above, the following steps are also included: inputting overlay mark parameters and designing overlay marks based on these parameters. It should be understood that overlay marks are typically designed based on overlay mark parameters. Based on the OPC model, different overlay mark parameters under different conditions can simulate different overlay marks. Users can select overlay marks that meet manufacturability requirements and fabricate them on the overlay mark mask master. The overlay mark parameters include any one or more combinations of the basic graphic, mark period (PITCH), and critical linewidth (CD). Please refer to [link to relevant documentation]. Figure 3 The basic graphics types include any one of BasicLS, ParallelST_P(N), VertST_P(N), and 2DST_P(N). Please refer to the following: Figure 2When the base pattern is BasicLS, the critical dimension (CD) refers to a special line pattern designed to reflect the width of integrated circuit feature lines in the photomask manufacturing and lithography process, used to evaluate and control the pattern processing accuracy of the process. In this embodiment, the critical dimension (CD) value ranges from 300-399nm, with a step size of 1nm. The overlay mark period (PITCH) refers to the period required for the critical dimensions to form the base pattern. The overlay mark period (PITCH) value is only the distance between two adjacent critical dimensions (CD) in the base pattern, with a value of 700-799nm and a step size of 1nm. The overlay mark can be set according to the overlay mark parameters.

[0064] It is worth noting that different styles of overlay marks can be designed based on different overlay mark parameters. The rapid screening method for manufacturability of overlay marks provided in this embodiment can further screen the overlay mark parameters corresponding to the overlay marks after screening the overlay marks that meet the manufacturability requirements. That is, the critical dimension (CD) and marking period (PITCH) value that meet the manufacturability requirements can be directly obtained through rapid screening using this method.

[0065] In step S1 above, the upper and lower limits of the preset range are selected as extreme process window conditions. It should be understood that the larger the process variation bandwidth value, the worse the manufacturability of the corresponding overlay mark. Users can calculate the process variation bandwidth value corresponding to the overlay mark based on the extreme process window as an extreme condition, so as to filter out overlay marks with poor manufacturability, that is, filter out overlay marks with large process variation bandwidth values, forming a preliminary screening with high convenience.

[0066] Furthermore, the process window conditions include the focus value and the light dose value.

[0067] Optionally, the focus value variable range is -150~150nm, and can also be -120~120nm, -100~100nm, -80~80nm, -60~60nm, -40~40nm, or -20~20nm. Specifically, the specific focus value is related to the step size setting. For example, when the step size is set to 10, the focus value can be ±10nm, ±20nm, ±20nm, ±30nm, ±40nm, ±50nm, ±60nm, ±70nm, ±80nm, ±90nm, ±100nm, ±110nm, ±120nm, ±130nm, ±140nm, ±150nm, or 0. When the step size is set to 50, the focus value can be ±150nm, ±100nm, ±50nm, or 0. That is, different step sizes result in different specific focus values. The depth of focus (DOF) is a crucial parameter for measuring the photolithography window (PW) of the exposure process. It indicates the relationship between the imaging quality of the exposure system and the position of the wafer surface. Within the DOF range, the quality of the exposure imaging can be guaranteed. The DOF during exposure must be significantly greater than the unevenness of the wafer surface to ensure the yield of the photolithography process.

[0068] Optionally, the range of the light dose value variable is -0.1 to 0.1. The range of the light dose value variable can also be -0.09 to 0.09, -0.08 to 0.08, -0.07 to 0.07, -0.06 to 0.06, -0.05 to 0.05, -0.04 to 0.04, -0.03 to 0.03, -0.02 to 0.02, or -0.01 to 0.01. Specifically, the specific value of the light dose value is also related to the step size setting. For example, when the step size is set to 0.01, the light dose value can be ±0.1, ±0.09±0.08, ±0.07, ±0.06, ±0.05, ±0.04, ±0.03, ±0.02, ±0.01, or 0. When the step size of the irradiance dose value is set to 0.05, the irradiance dose value can be ±0.1, ±0.05, or 0. That is, different step sizes result in different specific values ​​for the irradiance dose. Exposure dose, also known as exposure amount, refers to the integral of the illuminance Ev received by a surface element of an object over time t. Uniform light dose is crucial for the exposure of photoresist and also affects the quality of the exposure imaging. Optical exposure systems can form an exposure energy range that meets the design layout requirements. This range is typically defined by the exposure energy selection range where the change in the critical linewidth CD value detected by the exposure results is within the range of -0.1 to 0.1.

[0069] This embodiment limits the range of focus value and light dose value, allowing users to quickly select extreme process window conditions and analyze overlay marks through preset process window conditions, thereby quickly eliminating overlay marks with poor manufacturability. For example, when the focus value variable range is -150~150nm, and the step size is set to 10, and the light dose value variable range is -0.1~0.1, and the step size is set to 0.01, then the focus values ​​of -150nm and 150nm are selected as extreme process window conditions, and the light dose values ​​of -0.1 and -0.1 are selected as extreme process window conditions, which is simple and convenient.

[0070] It should be noted that the process window value calculated based on the preset model and within a preset range of window conditions does not refer to a specific numerical value, but rather to a combination of multiple parameters that can assess the manufacturability of overlay marks. The quantitative relationship of the process window values ​​also corresponds one-to-one with the quantitative relationship of the overlay marks. For example, if we need to analyze the manufacturability of 3000 overlay marks and select 651 extreme process window conditions, we can calculate a set of process window values ​​corresponding to one overlay mark. Each set of process window values ​​contains multiple parameters used to assess manufacturability, meaning that the final number of process variation bandwidth values ​​is also 3000.

[0071] Please combine Figure 1 and Figure 2 In step S21 above, calculating the first number of process variation bandwidth values ​​for the overlay marks based on extreme process window conditions using a preset model further includes the following step: calculating the first number of process variation bandwidth values ​​based on the preset model in a first-time calculation. It should be understood that in this embodiment, the first number of process variation bandwidth values ​​can be obtained in a first-time calculation based on the preset model for the overlay marks. Specifically, the preset model is an OPC model, which can calculate the process window value of the overlay marks based on window process conditions. This embodiment calculates the first number of process variation bandwidth values ​​using the OPC model under extreme process conditions, which is faster and more efficient than the prior art that directly calculates the process window value.

[0072] Furthermore, the difference between the first quantity and the second quantity is set as the third quantity; based on the process window conditions within a preset range, the time required to obtain the process window value corresponding to the overlay mark of the third quantity process variation bandwidth value through the preset model is the second time, and the ratio of the first time to the second time is the preset screening ratio; the ratio of the first time to the second time is less than 1.

[0073] Understandably, in step S22, a first screening is performed on the first number of process change bandwidth values ​​based on a preset screening ratio, so that some process change bandwidth values ​​are screened out to obtain a second number of process change bandwidth values, and the number of screened-out process change bandwidth values ​​is the third number.

[0074] This embodiment utilizes the fact that the time required to calculate the process variation bandwidth value of the overlay mark is much less than the time required to directly calculate the process window value corresponding to the overlay mark. Therefore, a preset screening ratio is set to perform a first screening on a first number of process variation bandwidth values, eliminating those that do not meet the requirements, thus achieving rapid screening. The time required to calculate the first number of bandwidth values ​​is called the first time; the time required to calculate the process window value corresponding to the third number of process variation bandwidth values ​​is called the second time. The ratio of the first time to the second time is less than 1, ensuring that the time required to calculate the first number of bandwidth values ​​is less than the time required to calculate the process window value corresponding to the third number of process variation bandwidth values. In other words, the time spent using the process variation bandwidth value of the overlay mark to screen the overlay mark is much less than the time spent directly calculating the process window value corresponding to the overlay mark and then screening, achieving rapid screening and saving computing power.

[0075] Furthermore, please combine Figure 1 and Figure 2 In step S22 above, the first screening of the first quantity of process change bandwidth values ​​based on the preset screening ratio includes the following steps: setting preset screening conditions based on the preset screening ratio, and performing the first screening of the first quantity of process change bandwidth values ​​based on the preset screening conditions to obtain the second quantity of process change bandwidth values.

[0076] It should be understood that preset filtering conditions can be set based on preset filtering ratios. For example, the filtering condition could be: sort the first quantity of process bandwidth values ​​from smallest to largest, and then retain the 30% of the smallest process bandwidth values ​​after sorting. These 30% of process bandwidth values ​​would then be the second quantity of process bandwidth values. By converting preset filtering ratios into filtering conditions, users can more intuitively issue filtering commands to perform the first filtering of process bandwidth values ​​according to their needs.

[0077] Specifically, the overlay marking process window conditions are the focus value and the light dose value. The preset ranges are: focus value variable range of -150~150nm, step size set to 10; light dose value variable range of -0.1~0.1, step size set to 0.01. The focus values ​​of -150nm and 150nm are selected as extreme process window conditions, and the light dose values ​​of -0.1 and -0.1 are selected as extreme process window conditions. Selecting 10,000 overlay marks, the time taken to calculate the process variation bandwidth value of 10,000 overlay marks based on the extreme window conditions using the preset model is 479 seconds. According to the screening criteria, the process variation bandwidth values ​​are sorted from smallest to largest, then the largest 70% of the process variation bandwidth values ​​are removed, and the smallest 30% of the process variation bandwidth values ​​are retained. The time taken to calculate the process window value based on the preset range of process window conditions is 638.8 seconds. The total time is 1117.8 seconds. The time required to directly calculate the process window value corresponding to 10,000 overlay marks using a preset model is 2129.3 seconds, which is much longer than the total time of 1117.8 seconds calculated based on this embodiment. Meanwhile, the time required to calculate the process window value of the overlay marks corresponding to the 70% largest process variation bandwidth value based on the preset model is 1490.5 seconds, which is much longer than the 479 seconds required to calculate 10,000 overlay marks based on extreme window conditions. In other words, this embodiment eliminates overlay marks with poor manufacturability by analyzing and calculating the process variation bandwidth value of overlay marks with shorter calculation times, reducing the number of complex calculation iterations of process window values ​​under all exposure process window condition variables, thus saving computing resources and time costs for software users.

[0078] In step S4 above, a second screening is performed on the process window value to be processed based on preset criteria. It should be understood that it is usually necessary to analyze the manufacturability of the overlay marks. After the analysis, it is determined that the overlay marks can be manufactured to form an overlay mark mask master. The preset criteria are usually a preset range of focus depth. Specifically, the focal depth range is 200-300nm. For example, when performing manufacturability screening on 10,000 overlay marks, 3,500 overlay marks are selected after the first screening. Based on a preset model, the process window value corresponding to the overlay marks is calculated. Among the 3,500 overlay marks, 3,000 overlay marks meet the requirements of a focal depth of 200-300nm. A second screening is performed to remove 500 overlay marks whose focal depth values ​​are outside the preset focal depth range. That is, the 3,000 overlay marks resulting from the second screening are the overlay marks that meet the manufacturability conditions. Therefore, after the initial screening using the process variation bandwidth value, a second number of process variation bandwidth values ​​are obtained. Then, the process window values ​​to be processed obtained by calculating the overlay marks corresponding to the second number of process variation bandwidth values ​​are screened a second time to obtain manufacturable overlay marks.

[0079] In step S4 above, the second screening of the process window value to be processed based on the preset standard further includes the following steps: obtaining the overlay mark parameters of the overlay mark corresponding to the process window value, and storing the overlay mark in a preset storage module. It should be understood that... (See also...) Figure 5 When the manufacturability rapid screening method for overlay marks provided in this embodiment is used for screening, the overlay mark parameters corresponding to the screened process window values ​​will be stored in the storage module 14. When the user needs to make an overlay mark mask master, the overlay mark data in the storage module 14 can be read through an external terminal device. For example, the user can read the overlay mark period (PITCH) value and the critical dimension (CD) value, and make the overlay mark mask master directly on the mask according to the overlay mark period (PITCH) value and the critical dimension (CD) value, which is highly convenient.

[0080] To better demonstrate the rapid screening of manufacturability in this embodiment, the present invention further provides the following experimental groups and comparison groups:

[0081] Experimental Group 1: Focus values ​​of -150nm and 150nm were selected as extreme process window conditions, and light dose values ​​of -0.1 and -0.1 were selected as extreme process window conditions. The start time was recorded. Based on the extreme process window conditions, the first number of process variation bandwidth values ​​were calculated using a preset model for the overlay marks. The time for obtaining the process variation bandwidth values ​​was recorded. The first number of process variation bandwidth values ​​were sorted from smallest to largest, and the filtering condition was set to retain the smallest 30% of the sorted process bandwidth values. The overlay marks corresponding to the smallest 30% of process bandwidth values ​​were calculated using an OPC model based on a preset range of process window conditions to obtain the process window values ​​corresponding to 30% of the overlay marks. The preset range refers to the focus value variable range being -150~150nm, with a step size of 10. The light dose value variable range is -0.1~0.1, with a step size of 0.01. The end time was recorded, and the total experimental time was obtained by subtracting the start time from the end time.

[0082] Experimental Group 2: The difference between it and Experimental Group 1 is that the screening condition is set to retain the 15% with the smallest process bandwidth value after sorting.

[0083] Experimental Group 3: The difference between it and Experimental Group 1 above is that the screening condition is set to retain the 20% with the smallest process bandwidth value after sorting.

[0084] Experimental Group 4: The difference between it and Experimental Group 1 above is that the screening condition is set to retain the 25% with the smallest process bandwidth value after sorting.

[0085] Experimental Group 5: The difference between it and Experimental Group 1 above is that the screening condition is set to retain the 35% with the smallest process bandwidth value after sorting.

[0086] Experimental Group 6: The difference between it and Experimental Group 1 above is that the screening condition is set to retain the 40% with the smallest process bandwidth value after sorting.

[0087] Comparison group: Select 10,000 overlay marks, record the start time, directly calculate the corresponding process window value through the OPC model, filter out overlay marks with poor manufacturability, record the number of overlay marks that meet the manufacturability standard, record the end time, and subtract the start time from the end time to obtain the total time of the comparison group.

[0088] Table 1. Comparison of calculation time between experimental groups 1-6 and the control group.

[0089]

[0090] According to the comparison results of calculation time between experimental groups 1-6 and the control group in Table 1, the time consumed by experimental groups 1-6 is less than that consumed by the control group. That is, by calculating the process change bandwidth value of the overprinted mark, setting preset screening conditions based on the preset screening ratio, filtering the overprinted mark based on the preset screening conditions to obtain the process window value to be processed, and filtering the value to be processed based on preset parameters to obtain the process window value, the effect of fast screening and saving computing power is achieved.

[0091] Please see Figure 5 This invention also provides an apparatus 1 for use in the above-described rapid screening method for manufacturability of overlay markings, the apparatus comprising:

[0092] Calculation module 11: Calculates the initial process variation bandwidth value based on extreme process window conditions;

[0093] Input module 12: Used to input process window conditions within a preset range;

[0094] Selection module 13: used to perform a first screening of the initial process variation bandwidth value based on a preset screening ratio, or to perform a second screening of the process window value to be processed based on a preset standard range to obtain the final process window value.

[0095] The device 1 also includes a storage module 14 for storing the acquired final process window value. It should be understood that by storing the acquired final process window value, the user can easily retrieve the process window value through an external terminal when needed, which is highly convenient.

[0096] The device 1 provided in this embodiment of the invention has the same beneficial effects as the above-described rapid screening method for manufacturability of overlay markings, and will not be described in detail here.

[0097] Please see Figure 6 A computer device 2, applied to the above-mentioned rapid screening method for manufacturability of overlay marks, includes a memory 21, a processor 22, and a computer program 23 stored on the memory 21. The processor 22 executes the computer program 23 to implement the steps of the rapid screening method for manufacturability of overlay marks.

[0098] The computer device 2 provided in this embodiment of the invention has the same beneficial effects as the above-described rapid screening method for manufacturability of overlay markings, and will not be described in detail here.

[0099] Compared with the prior art, the rapid screening method, apparatus, and computer equipment for manufacturability of overlay marking provided by the present invention have the following beneficial effects:

[0100] 1. This invention provides a rapid screening method for the manufacturability of overlay marks, comprising the following steps: inputting process window conditions within a preset range, and selecting the upper and lower limits as extreme process window conditions; calculating an initial process variation bandwidth value based on the extreme process window conditions, and performing a first screening on the initial process variation bandwidth value based on a preset screening ratio; calculating a process window value to be processed for the overlay marks corresponding to the screened process variation bandwidth values; performing a second screening on the process window values ​​to be processed based on a preset standard range to obtain a final process window value; and screening out the overlay marks corresponding to the final process window value. The rapid screening method for manufacturability of overlay marks provided in this embodiment employs a two-step screening approach. It selects upper and lower limits within a preset range as extreme process window conditions. The extreme process conditions are used to calculate the process variation bandwidth value corresponding to the overlay mark. The time required to calculate the process variation bandwidth value of the overlay mark using the preset model is significantly less than the time required to directly calculate the process window value corresponding to the overlay mark, greatly reducing the time spent on the first screening. Then, the overlay marks corresponding to the screened process bandwidth values ​​are calculated to obtain the process window value to be processed. Finally, the process window value to be processed is screened a second time to obtain a process window value that meets the preset standards, resulting in high screening efficiency.

[0101] 2. The embodiment of this invention calculates an initial process variation bandwidth value based on extreme process window conditions. The first screening of this initial process variation bandwidth value based on a preset screening ratio includes the following steps: calculating a first number of process variation bandwidth values ​​for the overlay marks using a preset model based on extreme process window conditions; and performing a first screening on the first number of process variation bandwidth values ​​based on the preset screening ratio to obtain a second number of process variation bandwidth values, where the second number is less than the first number. By analyzing the process variation bandwidth values ​​of overlay marks that take less time to calculate, overlay marks with poor manufacturability are eliminated, reducing the number of complex calculation iterations of the process window value under all exposure process window condition variables, thus saving computing resources and time costs for software users.

[0102] 3. The process window conditions in this embodiment of the invention include a focus value and a light dose value. The focus value ranges from -150 to 150 nm, and the light dose value ranges from -0.1 to 0.1. By setting the ranges of the focus value and light dose value, users can quickly select extreme process window conditions and analyze overlay marks through preset process window condition ranges, thereby quickly eliminating overlay marks with poor manufacturability.

[0103] 4. The embodiment of the present invention, which calculates the first number of process variation bandwidth values ​​for overlay marks based on extreme process window conditions using a preset model, further includes the following step: calculating the first number of process variation bandwidth values ​​in a first time based on the OPC model. Obtaining the first number of process variation bandwidth values ​​through this first-time calculation is faster than the prior art which directly calculates the process window values.

[0104] 5. In this embodiment of the invention, the difference between the first quantity and the second quantity is set as the third quantity; the time required to calculate the process window value of the overlay mark corresponding to the third quantity of process variation bandwidth values ​​based on the process window conditions within a preset range is the second time, and the ratio of the first time to the second time is the preset screening ratio. By setting the preset screening ratio, the process variation bandwidth values ​​of the first quantity of overlay marks are first screened to remove process bandwidth values ​​that do not meet the requirements, so as to achieve the purpose of rapid screening.

[0105] 6. In this embodiment of the invention, the ratio of the first time to the second time is less than 1. That is, the time spent calculating the process variation bandwidth value by first performing extreme process window conditions, filtering the overlay marks, and then calculating the process window value of the filtered overlay marks is less than the time spent directly calculating the process window value of all overlay marks and then filtering out process window values ​​that do not meet the standard. This achieves the purpose of rapid filtering.

[0106] 7. The preset standard in this embodiment of the invention is the focusing depth; the preset standard ranges from 200 to 300 nm. Based on the preset standard, the process window value to be processed can be quickly filtered to obtain the final process window value required by the user. The method is convenient and efficient.

[0107] 8. This invention also provides an apparatus that has the same beneficial effects as the above-described method for rapid screening of manufacturability of overlay markings, which will not be described in detail here.

[0108] 9. The present invention also provides a computer device that has the same beneficial effects as the above-described method for rapid screening of manufacturability of overlay markings, which will not be described in detail here.

[0109] The foregoing has provided a detailed description of a rapid screening method, apparatus, and computer device for manufacturability of overlay markings disclosed in embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of overlay mark manufacturability rapid screening, the method comprising: The method comprises the following steps: ​ inputting process window conditions in a preset range, selecting upper limit values and lower limit values in the process window conditions as extreme process window conditions; calculating initial process variation bandwidth values based on the extreme process window conditions, and performing first screening on the initial process variation bandwidth values based on a preset screening ratio; calculating process window values to be processed based on the overlay marks corresponding to the screened process variation bandwidth values; performing second screening on the process window values to be processed based on a preset standard range to obtain final process window values; screening out overlay marks corresponding to the final process window values.

2. The overlay mark manufacturability quick- sieving method of claim 1, wherein: The calculating of the initial process variation bandwidth values based on the extreme process window conditions comprises the following steps: calculating a first number of process variation bandwidth values based on the overlay marks and the extreme process window conditions by using a preset model; performing first screening on the first number of process variation bandwidth values based on a preset screening ratio to obtain a second number of process variation bandwidth values, wherein the second number is less than the first number.

3. The overlay mark manufacturability quick-siee method of claim 1, wherein: The process window conditions comprise a focus value and an exposure dose value.

4. The overlay mark manufacturability quick-siee method of claim 3, wherein: The variable range of the focus value is -150-150 nm, and the variable range of the exposure dose value is -0.1-0.

1.

5. The overlay mark manufacturability quick-siee method of claim 2, wherein: The calculating of the first number of process variation bandwidth values based on the overlay marks and the extreme process window conditions by using the preset model further comprises the following step: calculating the first number of process variation bandwidth values based on an OPC model at a first time.

6. The overlay mark manufacturability quick- sieving method of claim 5, wherein: The difference between the first number and the second number is set as a third number; the time required for calculating process window values based on the overlay marks corresponding to the third number of process variation bandwidth values by using the preset model based on the process window conditions in the preset range is a second time, and the ratio of the first time to the second time is the preset screening ratio; the ratio of the first time to the second time is less than 1.

7. The rapid screening method for manufacturability of overlay marking as described in claim 1, characterized in that: The calculating of the process window values to be processed based on the overlay marks corresponding to the screened process variation bandwidth values comprises the following step: calculating the process window values to be processed based on the overlay marks corresponding to the screened process variation bandwidth values based on the process window conditions in the preset range.

8. The rapid screening method for manufacturability of overlay marking as described in claim 1, characterized in that: The preset standard is a focus depth, and the preset standard range is 200-300 nm.

9. An overlay mark manufacturability rapid screening apparatus applied to the overlay mark manufacturability rapid screening method according to any one of claims 1-8, characterized in that: The overlay mark manufacturability rapid screening device comprises: a calculating module for calculating initial process variation bandwidth values based on extreme process window conditions; an input module for inputting process window conditions in a preset range; a selection module for performing first screening on the initial process variation bandwidth values based on a preset screening ratio, or performing second screening on process window values to be processed based on a preset standard range to obtain final process window values.

10. A computer device applied to the overlay mark manufacturability rapid screening method according to any one of claims 1-8, characterized in that: The device comprises a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to realize the steps of the overlay mark manufacturability rapid screening method. The device comprises a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to realize the steps of the overlay mark manufacturability rapid screening method.

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