Auxiliary graph adding method and related device
By correcting the wafer design graphics and accurately adding auxiliary graphics, the problem of insufficient adaptability of traditional auxiliary graphics in extremely small pitch scenarios is solved, and the graphic resolution capability and chip yield of the lithography process are improved.
Patent Information
- Application Number
- CN202511189742.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-10-14
AI Technical Summary
In the existing technology, traditional auxiliary graphics are not adaptable enough in extremely small pitch scenarios, resulting in redundant graphics on the wafer, affecting the chip manufacturing yield.
By modifying the original design drawing, it is determined whether the interval between adjacent graphics in the space is less than the threshold. If so, target auxiliary graphics are added to connect with them to adapt to different layout scenarios and enhance light intensity concentration and contrast.
It avoids the generation of redundant patterns on the wafer, improves the chip manufacturing yield, and enhances the pattern resolution capability and clarity of the lithography process.
Smart Images
Figure CN120779656A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor lithography technology, and in particular to a method for adding auxiliary graphics and related devices. Background Art
[0002] In semiconductor lithography manufacturing, as process dimensions continue to shrink, mask patterns shrink below the resolution capability of the lithography machine, leading to frequent pattern shrinkage and line breakage. Existing solutions typically incorporate traditional auxiliary patterns into the OPC (Optical Proximity Correction) process to improve resolution. However, when two main patterns are too close or the line width of the auxiliary pattern is out of control, this solution can easily produce redundant patterns on the wafer, causing wafer defects. Therefore, addressing the limited adaptability of traditional auxiliary patterns in existing solutions for extremely fine pitch scenarios and improving wafer production yield has become a pressing technical challenge in semiconductor lithography. Summary of the Invention
[0003] Based on the above problems, the present application provides a method for adding auxiliary graphics to solve the problem of redundant graphics on the wafer, which leads to a decrease in chip manufacturing yield due to the insufficient adaptability of traditional auxiliary graphics in scenarios such as small pitch and complex layout.
[0004] The embodiments of this application disclose the following technical solutions:
[0005] A first aspect of the present application provides a method for adding an auxiliary graphic, the method comprising:
[0006] Modify the original design drawing to obtain the target design drawing;
[0007] Determining whether the spatial interval between two spatially adjacent graphics in the target design drawing is greater than a preset interval threshold;
[0008] If the spatial interval is less than or equal to the interval threshold, a target auxiliary graphic is added between the two spatially adjacent graphics; and the target auxiliary graphic is connected to one of the two spatially adjacent graphics.
[0009] In an optional implementation, adding the target auxiliary graphic between two spatially adjacent graphics includes:
[0010] Determine a spatial layout scene to which the two spatially adjacent graphics belong; the spatial layout scene includes a unilateral dense layout scene and a bilaterally symmetrical layout scene;
[0011] Based on the spatial layout scenario, the target auxiliary graphic is added between two adjacent graphics in the space.
[0012] In an optional implementation, if the spatial layout scenario is a unilateral dense layout scenario, adding the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scenario includes:
[0013] The target auxiliary graphic is added between two adjacent graphics in the space and connected to a smaller graphic of the two graphics.
[0014] In an optional implementation, the spatial layout scenario is the bilaterally symmetrical layout scenario, and adding the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scenario includes:
[0015] Two target auxiliary graphics are added between two adjacent graphics in the space, and each target auxiliary graphic is connected to one of the two graphics.
[0016] In an optional implementation, the modifying of the original design drawing to obtain the target design drawing includes:
[0017] Based on the optical proximity effect model, the edges of the graphics in the original design drawing are cut, corner compensated or size adjusted to obtain the target design drawing.
[0018] In an optional implementation, the method further includes:
[0019] If the spatial interval is greater than the interval threshold, a traditional auxiliary graphic is added between the two spatially adjacent graphics; the traditional auxiliary graphic is not connected to each of the two spatially adjacent graphics.
[0020] A second aspect of the present application provides an auxiliary image processing device, the device comprising:
[0021] The target design drawing acquisition module is used to modify the original design drawing to obtain the target design drawing;
[0022] A size determination module is used to determine whether the space between two spatially adjacent graphics in the target design drawing is greater than a preset space threshold;
[0023] A graphics adding module is configured to add a target auxiliary graphic between two spatially adjacent graphics if the spatial interval is less than or equal to the interval threshold; the target auxiliary graphic is connected to one of the two spatially adjacent graphics.
[0024] In an optional implementation, the graphics adding module includes:
[0025] A layout scene determination unit, configured to determine a spatial layout scene to which two spatially adjacent graphics belong; the spatial layout scene includes a unilaterally dense layout scene and a bilaterally symmetrical layout scene;
[0026] An adding position determining unit is configured to add the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scene.
[0027] A third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any implementation of the first aspect.
[0028] A fourth aspect of the present application provides an electronic device, including:
[0029] a memory having a computer program stored thereon;
[0030] A processor is used to execute the computer program in the memory to implement the steps of the method introduced in any implementation manner of the first aspect.
[0031] Compared with the existing technology, this application has the following beneficial effects:
[0032] The present application provides a method for adding auxiliary graphics, including: correcting the original design drawing to obtain a target design drawing; determining whether the spatial interval between two spatially adjacent graphics in the target design drawing is greater than a preset interval threshold; if it is determined that the spatial interval is less than or equal to the interval threshold, adding the target auxiliary graphics between the two spatially adjacent graphics. The connection between the target auxiliary graphics and the graphics in the target design drawing will not be exposed on the wafer, avoiding the appearance of additional graphics on the wafer due to exposure problems; at the same time, the contrast of the connection can be enhanced, which helps to optimize the contour shape of the overall image and keep it in a good state. In other words, the target auxiliary graphics accurately adapt to the small-pitch scene on the one hand, avoiding the generation of redundant images on the wafer; on the other hand, it enhances the light intensity concentration and contrast of the edge of the main graphic, effectively improving the resolution ability of the graphics during the photolithography process, making the main graphic imaging clearer. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0034] Figure 1 A schematic diagram of generating redundant patterns on a wafer provided in an embodiment of the present application;
[0035] Figure 2 A flowchart of a method for adding auxiliary graphics provided in an embodiment of the present application;
[0036] Figure 3 A schematic diagram comparing a target auxiliary graphic and a traditional auxiliary graphic provided in an embodiment of the present application;
[0037] Figure 4 A schematic diagram of adding target auxiliary graphics to a one-sided dense layout scenario provided by an embodiment of the present application;
[0038] Figure 5 A schematic diagram of adding target auxiliary graphics to another one-sided dense layout scenario provided by an embodiment of the present application;
[0039] Figure 6 A schematic diagram of adding target auxiliary graphics to a bilaterally symmetrical layout scenario provided in an embodiment of the present application;
[0040] Figure 7 A schematic structural diagram of a device for adding auxiliary graphics provided in an embodiment of the present application. DETAILED DESCRIPTION
[0041] In the photolithography process of semiconductor manufacturing, photomasks are a key technology for printing patterns onto substrates such as semiconductor wafers. They are used to precisely define the desired pattern on the substrate. However, optical effects such as light interference during the photolithography process can cause the printed pattern to deviate from the intended design.
[0042] Currently, sub-resolution assist features (SRAFs) are commonly used in optical proximity correction (OPC) to address this issue. SRAFs, which are smaller than the lithography resolution limit and therefore do not form an image on the wafer, are strategically placed around the primary pattern to manipulate the light field distribution around it, effectively offsetting interference from optical effects and improving the accuracy of primary pattern imaging.
[0043] However, as process dimensions continue to shrink, when the mask pattern shrinks to a level below the resolution capability of the lithography machine, pattern reduction and line breakage problems occur frequently. Figure 1 A schematic diagram of generating redundant patterns on a wafer provided in an embodiment of the present application. Figure 1 (a) is a schematic diagram of the state of the photomask corresponding to the substrate pattern layout in the photolithography process when no auxiliary pattern is added; Figure 1 (b) is a schematic diagram showing that an unreasonable auxiliary pattern is added, resulting in redundant patterns on the wafer. Figure 1The blue pattern in the figure represents the target pattern that should be accurately printed on the substrate; the red circle represents the simulated ADI contor (the simulated detection mark of the pattern outline after photoresist exposure and before etching), and the orange pattern between the two blue strips represents the redundant pattern actually generated on the substrate.
[0044] Combine Figure 1 As shown in the figure, the size and layout of the traditional auxiliary pattern are not adapted to the main pattern spacing and light field characteristics; during the photolithography process, the traditional auxiliary pattern causes abnormal interference and diffraction of the light field, making the light intensity distribution out of control, and thus Figure 1 In (b), redundant patterns are generated in the corresponding area of the substrate. This reduces chip manufacturing yield, increases chip production costs, prolongs production cycles, and even affects the final performance and reliability of the chip.
[0045] Incorporating traditional auxiliary patterns into the optical proximity correction process to improve resolution requires strict control of the auxiliary pattern's line width. Excessive line width, or proximity between the auxiliary pattern and the main pattern, can create redundant patterns on the wafer, causing defects and impacting wafer yield. Therefore, addressing the inadequate adaptability of traditional auxiliary patterns in existing solutions for extremely fine-pitch applications and improving wafer production yield has become a pressing technical challenge in semiconductor lithography.
[0046] To solve the above problems, the present application provides a method for adding auxiliary graphics, including: correcting the original design drawing to obtain a target design drawing; judging whether the spatial interval between two spatially adjacent graphics in the target design drawing is greater than a preset interval threshold; if it is determined that the spatial interval is less than or equal to the interval threshold, then adding the target auxiliary graphic between the two spatially adjacent graphics.
[0047] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0048] Figure 2 This is a flow chart of a method for adding auxiliary graphics provided in an embodiment of the present application. Figure 2 As shown, the method for adding auxiliary graphics disclosed in this application includes:
[0049] S201, modifying the original design drawing to obtain a target design drawing.
[0050] After importing the chip design data, the edges of the graphics in the original design drawing can be cut, corner compensated or resized based on the optical proximity effect model to obtain the target design drawing.
[0051] Specifically, for graphics with the risk of edge blurring, the optical proximity effect model is used to adopt high-precision cutting technology to decompose continuous edges into short line segments that are easier to be accurately restored by the lithography system, ensuring a clear presentation of the edge contour. To address the distortion problem that is prone to occur at the corners of the graphics, a corner compensation strategy is implemented to offset the corner rounding phenomenon caused by the optical effect by adding specific auxiliary graphics in the corner area or adjusting the corner angle. At the same time, based on the dimensional deviation data predicted by the model, the key dimensions of the graphics are precisely adjusted at the micron or even nanometer level to obtain a target design drawing that can adapt to the actual lithography process.
[0052] This application does not limit the specific type of optical proximity effect model. For example, it can be a model-based optical proximity correction (MB-OPC) model or a complex model of the extreme ultraviolet optical proximity effect model. Those skilled in the art can determine the specific type of optical proximity effect model based on actual needs.
[0053] S202: Determine whether the spatial interval between two spatially adjacent graphics in the target design drawing is greater than a preset interval threshold.
[0054] Once the target design is obtained, to ensure the rationality of the pattern layout and the feasibility of subsequent manufacturing processes, a systematic check is performed on all spatially adjacent pattern combinations within the target design. Specifically, for each pair of spatially adjacent patterns, the shortest spatial distance (also known as the spatial separation) between the two adjacent patterns is accurately measured. This measured separation is then compared and analyzed with a pre-set separation threshold.
[0055] Among them, the preset interval threshold is a value determined based on the resolution capability of the lithography machine, process node parameters and graphic size.
[0056] For example, in mature processes (180nm and above), the spacing threshold is typically 0.5μm-2μm; in advanced processes (7nm-28nm), the spacing threshold is reduced to 20nm-200nm; for extreme ultraviolet lithography processes, the spacing threshold is reduced to 10nm-150nm.
[0057] S203: If the spatial interval is less than or equal to the interval threshold, add a target auxiliary graphic between the two spatially adjacent graphics.
[0058] For any group of two spatially adjacent graphics in the target design drawing, if the spatial interval between the two spatially adjacent graphics in this group is less than or equal to the preset interval threshold, that is, the two main graphics are too close, the target auxiliary graphic is added between the two spatially adjacent graphics in this group.
[0059] Figure 3 A schematic diagram comparing a target auxiliary graphic and a traditional auxiliary graphic provided in an embodiment of the present application. Figure 3 The orange pattern in (a) is a traditional auxiliary pattern. Figure 3 The orange pattern in (b) is the target auxiliary pattern. Figure 3 It can be seen that the target auxiliary figure is connected to one of the two spatially adjacent figures; the traditional auxiliary figure is located between a group of two spatially adjacent figures and is not connected to any of the figures. Figure 3 Reference for the meaning of various colors in the icons Figure 1 It is introduced in , so I will not repeat it here.
[0060] It should be emphasized that this application only requires that the target auxiliary graphic be located between two spatially adjacent graphics and connected to one of the two spatially adjacent graphics. This application does not limit the shape of the target auxiliary graphic, that is, the target auxiliary graphic can be rectangular, square, or straight. Those skilled in the art will need to select corresponding auxiliary graphics of different shapes as the target auxiliary graphic based on actual circumstances.
[0061] It can be understood that the main graphics mentioned in the background technology of this application are graphics in the target design drawing corresponding to the auxiliary graphics added thereto, and a group of two spatially adjacent graphics are two main graphics.
[0062] In an optional implementation, adding a target auxiliary graphic between two adjacent graphics in the space specifically includes the following steps:
[0063] The first step is to determine the spatial layout scene to which two adjacent graphics belong.
[0064] Among them, the spatial layout scenarios include unilateral dense layout scenarios and bilateral symmetrical layout scenarios.
[0065] A single-sided dense layout scenario refers to a layout in which, in a target design graphic, one side of a main graphic is densely populated with multiple other main graphics of smaller sizes.
[0066] A bilaterally symmetrical layout scenario refers to a layout in which the main graphics are symmetrically distributed in the target design graphics.
[0067] In the second step, based on the spatial layout scenario, the target auxiliary graphics are added between two adjacent graphics in the space.
[0068] Figure 4 A schematic diagram of adding target auxiliary graphics to a one-sided dense layout scenario provided in an embodiment of the present application. Figure 4 There are four main graphics in total (four blue rectangles). Figure 4 The three horizontally arranged main graphics are densely arranged on the left side of the vertically placed main graphics, forming a single-sided dense layout scene. Figure 4 Any horizontally placed main graphic or vertically placed main graphic in the image can be considered a pair of spatially adjacent graphics. In a single-sided dense layout scenario, for each pair of spatially adjacent images, the target auxiliary graphic (orange pattern) is added between the two spatially adjacent graphics, connected to the smaller of the two spatially connected graphics.
[0069] Figure 5 A schematic diagram of adding target auxiliary graphics to another one-sided dense layout scenario provided in an embodiment of the present application. Figure 5 There are seven main graphics in total (seven blue rectangles); among them, three horizontally arranged main graphics are densely arranged on the left side of the vertically placed main graphic, forming a one-sided dense layout scene; the other three horizontally arranged main graphics are densely arranged on the right side of the vertically placed main graphic, forming a one-sided dense layout scene. Figure 5 For any one-sided dense layout scene in , for each pair of spatially adjacent images in the scene, add the target auxiliary shape (orange pattern) between the two spatially adjacent shapes and at a position connected to the smaller shape of the two spatially connected shapes.
[0070] Figure 6 A schematic diagram of adding target auxiliary graphics to a bilaterally symmetrical layout scenario provided in an embodiment of the present application. Figure 6 There are a total of six main graphics (six blue rectangles), and the two adjacent main graphics in each row are symmetrically distributed, forming a bilaterally symmetrical layout scene. Figure 6 The two main shapes symmetrically distributed in each row in the can be considered a set of two spatially adjacent shapes. In a bilaterally symmetrical layout scenario, for each set of two spatially adjacent shapes, target auxiliary shapes are added between the two adjacent shapes, with each target auxiliary shape connected to one of the two spatially adjacent shapes.
[0071] Combine Figure 4 、 Figure 5 and Figure 6It can be seen that when it is determined that the distance between two adjacent main graphics in the target design is too close, and traditional auxiliary images cannot be effectively inserted, resulting in the inability to solve the size reduction problem of 2D line end graphics, a target auxiliary graphic can be inserted between the two adjacent main graphics. On the one hand, the target auxiliary graphic accurately adapts to the small pitch scene, avoiding the problem of redundant imaging that traditional auxiliary graphics easily produce in a small space. On the other hand, it enhances the light intensity concentration and contrast at the edge of the main graphic, effectively improving the resolution ability of the graphic during the lithography process and making the main graphic image clearer.
[0072] S204: If the spatial interval is greater than the interval threshold, a traditional auxiliary graphic is added between the two spatially adjacent graphics.
[0073] The traditional auxiliary graphics are not connected to any of the two graphics in a set of spatially adjacent graphics. Figure 3 As shown in (a), no further details will be given here.
[0074] In one optional implementation, after adding auxiliary graphics (traditional auxiliary images or target auxiliary graphics) between multiple groups of spatially adjacent graphics in the target design, the imaging effect of the added auxiliary graphics on the target design needs to be verified. If the imaging results show image distortion or other defects, at least one of the size, shape, or position of the auxiliary graphics needs to be adjusted to ensure that the imaging effect meets the predetermined standards. This process may require multiple iterations until the imaging quality meets the requirements.
[0075] Based on the same inventive concept, the present application also discloses a device for adding auxiliary graphics. Figure 7 A schematic diagram of the structure of a device for adding auxiliary graphics provided in an embodiment of the present application. Figure 7 As shown, the auxiliary graphics adding device 700 disclosed in this application includes:
[0076] The target design drawing acquisition module 701 is used to modify the original design drawing to obtain the target design drawing;
[0077] A size determination module 702 is configured to determine whether the space between two spatially adjacent graphics in the target design is greater than a preset space threshold;
[0078] The graphics adding module 703 is configured to add a target auxiliary graphic between two spatially adjacent graphics if the spatial interval is less than or equal to the interval threshold; the target auxiliary graphic is connected to one of the two spatially adjacent graphics.
[0079] In an optional implementation, the graphic adding module 703 includes:
[0080] A layout scene determination unit, configured to determine a spatial layout scene to which two spatially adjacent graphics belong; the spatial layout scene includes a unilaterally dense layout scene and a bilaterally symmetrical layout scene;
[0081] An adding position determining unit is configured to add the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scene.
[0082] In an optional implementation, the adding position determining unit includes a first adding position determining subunit;
[0083] The first adding position determining subunit is configured to add the target auxiliary graphic between two adjacent graphics in the space and at a position connected to the smaller one of the two graphics.
[0084] In an optional implementation, the adding position determining unit includes a second adding position determining subunit;
[0085] The second adding position determining subunit is configured to add the two target auxiliary graphics between two adjacent graphics in the space, and each target auxiliary graphic is connected to one of the two graphics.
[0086] In an optional implementation, the target design drawing acquisition module 701 includes:
[0087] The target design drawing acquisition unit is used to cut, corner-compensate or size-adjust the edges of the graphics in the original design drawing based on an optical proximity effect model to obtain the target design drawing.
[0088] Based on the auxiliary image processing method and device provided in the aforementioned embodiments, the present application also provides a computer-readable storage medium, which stores a computer program, which, when executed by a processor, implements some or all of the steps in the auxiliary image processing method mentioned above.
[0089] Based on the auxiliary image processing method and apparatus provided in the aforementioned embodiments, the present application further provides an electronic device, including:
[0090] a memory having a computer program stored thereon;
[0091] A processor is used to execute the computer program in the memory to implement part or all of the steps in the auxiliary image processing method provided in the above embodiment.
[0092] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device embodiment described above is merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.
[0093] The above is merely one specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.
Claims
1. A method for adding auxiliary graphics, characterized in that: The method comprises: Modify the original design drawing to obtain the target design drawing; Determining whether the spatial interval between two spatially adjacent graphics in the target design drawing is greater than a preset interval threshold; If the spatial interval is less than or equal to the interval threshold, a target auxiliary graphic is added between the two spatially adjacent graphics; and the target auxiliary graphic is connected to one of the two spatially adjacent graphics.
2. The method according to claim 1, characterized in that The adding of the target auxiliary graphic between the two spatially adjacent graphics includes: Determine a spatial layout scene to which the two spatially adjacent graphics belong; the spatial layout scene includes a unilateral dense layout scene and a bilaterally symmetrical layout scene; Based on the spatial layout scenario, the target auxiliary graphic is added between two adjacent graphics in the space.
3. The method according to claim 2, characterized in that If the spatial layout scenario is the unilateral dense layout scenario, the adding the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scenario includes: The target auxiliary graphic is added between two adjacent graphics in the space and connected to a smaller graphic of the two graphics.
4. The method according to claim 2, characterized in that The spatial layout scenario is the bilaterally symmetrical layout scenario, and the adding of the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scenario includes: Two target auxiliary graphics are added between two adjacent graphics in the space, and each target auxiliary graphic is connected to one of the two graphics.
5. The method according to claim 1, wherein The process of modifying the original design drawing to obtain the target design drawing includes: Based on the optical proximity effect model, the edges of the graphics in the original design drawing are cut, corner compensated or size adjusted to obtain the target design drawing.
6. The method according to claim 1, characterized in that The method further comprises: If the spatial interval is greater than the interval threshold, a traditional auxiliary graphic is added between the two spatially adjacent graphics; the traditional auxiliary graphic is not connected to each of the two spatially adjacent graphics.
7. A device for adding auxiliary graphics, characterized in that: The device comprises: The target design drawing acquisition module is used to modify the original design drawing to obtain the target design drawing; A size determination module is used to determine whether the space between two spatially adjacent graphics in the target design drawing is greater than a preset space threshold; A graphics adding module is configured to add a target auxiliary graphic between two spatially adjacent graphics if the spatial interval is less than or equal to the interval threshold; the target auxiliary graphic is connected to one of the two spatially adjacent graphics.
8. The device according to claim 7, characterized in that The graphics adding module includes: A layout scene determination unit, configured to determine a spatial layout scene to which two spatially adjacent graphics belong; the spatial layout scene includes a unilaterally dense layout scene and a bilaterally symmetrical layout scene; An adding position determining unit is configured to add the target auxiliary graphic between two adjacent graphics in the space based on the spatial layout scene.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.
10. An electronic device, characterized in that: include: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 6.