A method and device for adding auxiliary graphics based on a light source

Abstract

The present invention relates to a method and device for adding auxiliary patterns based on a light source, belonging to the field of semiconductor technology, and solves the problem of unreasonable addition of auxiliary patterns caused by the inability of existing rule-based sub-resolution auxiliary patterns to adapt to changes in light source factors. The method includes: obtaining the light source information of a reference light source and a list of auxiliary pattern addition rules corresponding to the reference light source; when the light source information of the lithography light source is different from that of the reference light source, modifying the auxiliary pattern addition rules based on the light source information of the lithography light source to generate a modified list of auxiliary pattern addition rules corresponding to the lithography light source; and obtaining the auxiliary pattern addition rules for the layout according to the modified list of auxiliary pattern addition rules and adding the auxiliary patterns to be added to the layout according to the auxiliary pattern addition rules for the layout. The complexity of adding sub-resolution auxiliary patterns is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular, to a method and apparatus for adding auxiliary patterns based on a light source. Background Art

[0002] As a resolution enhancement technology, Sub-Resolution Assist Feature (SRAF) has been widely used in mass production since it was introduced at the 90nm node. Sub-resolution assist features are a series of small patterns below the lithography resolution added around the target pattern. These patterns are not transferred to the photoresist and only serve to enhance the imaging effect of the target pattern. By adding sub-resolution assist features, the imaging light intensity contrast of the target pattern can be effectively increased. Especially for sparsely distributed patterns, by adding sub-resolution assist features, such sparse patterns have the same pattern density as dense patterns in terms of geometric distribution, thereby improving the process window of the overall layout.

[0003] In practical engineering applications, a rule-based method is usually used to add sub-resolution assist features. The rules mainly come from model-based methods and the experience of engineers. For a new layout, when applying the rules to the layout, appropriate application conditions need to be selected from the rules to make the added sub-resolution assist features effective. Therefore, the selection of rules becomes the key to the accurate addition of sub-resolution assist features. For the same layout, such as a layout with the same line width and period, the same rules are often selected. However, the factors determining the process window come not only from the layout but also from the light source. Summary of the Invention

[0004] In view of the above analysis, embodiments of the present invention aim to provide a method and apparatus for adding auxiliary patterns based on a light source to solve the problem of unreasonable addition of auxiliary patterns caused by the inability of existing rule-based sub-resolution assist features to adapt to changes in light source factors.

[0005] On the one hand, an embodiment of the present invention provides a method for adding auxiliary patterns based on a light source, including: obtaining the light source information of a reference light source and a list of auxiliary pattern addition rules corresponding to the reference light source; when the light source information of the lithography light source is different from the light source information of the reference light source, modifying the auxiliary pattern addition rules based on the light source information of the lithography light source to generate a modified list of auxiliary pattern addition rules corresponding to the lithography light source; and obtaining the auxiliary pattern addition rules for the layout according to the modified list of auxiliary pattern addition rules and adding the auxiliary patterns to be added to the layout according to the auxiliary pattern addition rules for the layout.

[0006] The beneficial effects of the above technical solutions are as follows: The embodiments of the present application are re-explored with the changes in the light source and the core pattern size during the research and development towards more advanced nodes, that is, the sub-resolution assist feature addition rules are modified, so as to be able to omit the process steps of repeatedly matching the assist feature addition rules with the light source information of the lithography light source, reduce the complexity of sub-resolution assist feature addition, and save computing resources and time costs. By generating a modified assist feature addition rule list corresponding to the lithography light source, the complexity of sub-resolution assist feature addition can be reduced and the cost of simulation requirements can be reduced.

[0007] Based on a further improvement of the above method, the light source information of the lithography light source includes the shape distribution of the light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source.

[0008] Based on a further improvement of the above method, the assist feature is a sub-resolution assist feature. Among them, further modifying the sub-resolution assist feature based on the lithography light source further includes: modifying the distribution and symmetry of the sub-resolution assist feature according to the shape distribution of the lithography light source; assigning a modification weight or magnification to the assist feature addition rule according to the change in the sigma of the lithography light source; modifying the assist feature addition rule for different feature patterns according to the intensity distribution of the lithography light source; modifying the magnification of the assist feature addition rule according to the numerical aperture of the lithography light source; and modifying the assist feature addition rule for different directions according to the polarization direction of the lithography light source.

[0009] Based on a further improvement of the above method, the modified assist feature addition rule is inversely correlated with the sigma or numerical aperture of the lithography light source. Among them, when the sigma of the lithography light source increases, the period and distance in the corresponding modified assist feature addition rule decrease; or when the numerical aperture of the lithography light source increases, the period and distance in the corresponding modified assist feature addition rule decrease.

[0010] Based on a further improvement of the above method, the modified assist feature addition rule is stored in a modified assist feature addition rule list. The modified assist feature addition rule includes the geometric information of the sub-resolution assist feature to be added, the addition position information, and the applicable condition information; among them, the geometric information includes the line length, width, and orientation of the sub-resolution assist feature to be added; the position information includes the relative distance between the sub-resolution assist feature to be added and the target pattern; the applicable condition includes the scenario in which the modified assist feature addition rule is used.

[0011] For a further improvement based on the above method, obtaining the auxiliary graph addition rules for the layout according to the modified auxiliary graph addition rule list further includes: selecting a modified auxiliary graph addition rule from the modified auxiliary graph addition rule list based on the geometric features of the target graph in the layout, where the geometric features of the target graph include: the length, width, and orientation of the target graph, and the relative positions with other target graphs in the horizontal direction, vertical direction, and diagonal direction.

[0012] For a further improvement based on the above method, selecting a modified auxiliary graph addition rule from the modified auxiliary graph addition rule list based on the geometric features of the target graph in the layout further includes: Step 1, determining the core structure and its size of the target graph; Step 2, classifying the target graph according to the size, period, and surrounding graph features, where the classified target graphs include one-dimensional line graphs and two-dimensional structures; Step 3, for the one-dimensional line graph, selecting the modified auxiliary graph addition rule in the direction parallel to the line as the auxiliary graph addition rule for the layout according to the conditions defined in Step 1; Step 4, for the two-dimensional structure, combining the conditions defined in Step 1, selecting the modified auxiliary graph addition rule in the direction parallel to the line, perpendicular direction, and diagonal direction as the auxiliary graph addition rule for the layout.

[0013] For a further improvement based on the above method, obtaining the auxiliary graph addition rules for the layout according to the modified auxiliary graph addition rule list further includes: when the geometric features of the target graph are not in the modified auxiliary graph addition rule list, using the nearest neighbor approximation method to perform weighted averaging on the modified auxiliary graph addition rules of graphs with geometric dimensions similar to the target graph to obtain the auxiliary graph addition rules for the layout.

[0014] For a further improvement based on the above method, after adding all the auxiliary graphs to be added to the layout, it further includes: performing conflict cleaning and mask manufacturing rule checking on the layout to which the auxiliary graphs to be added have been added; and when both the conflict cleaning and the mask manufacturing rule checking pass, outputting the layout.

[0015] On the other hand, an embodiment of the present invention provides a device for adding auxiliary graphics based on a light source, including: an initial information acquisition module, a rule modification module, a layout rule acquisition module, and an auxiliary graphics addition module. Among them, the initial information acquisition module is used to acquire the light source information of a reference light source and a list of auxiliary graphics addition rules corresponding to the reference light source; the rule modification module is used to, when the light source information of a lithography light source is different from the light source information of the reference light source, modify the auxiliary graphics addition rules based on the light source information of the lithography light source to generate a modified list of auxiliary graphics addition rules corresponding to the lithography light source; and the layout rule acquisition module is used to acquire the auxiliary graphics addition rules for the layout according to the modified list of auxiliary graphics addition rules; the auxiliary graphics addition module is used to add the auxiliary graphics to be added to the layout according to the auxiliary graphics addition rules for the layout.

[0016] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0017] 1. Embodiments of the present application re-explore as the light source changes and the core graphic size changes during the research and development of more advanced nodes, that is, modify the (sub-resolution) auxiliary graphics addition rules, reduce the complexity of sub-resolution auxiliary graphics addition, save experimental and computing resources, and save time costs.

[0018] 2. By generating a modified list of auxiliary graphics addition rules corresponding to the lithography light source, the complexity of sub-resolution auxiliary graphics addition and the cost of simulation requirements can be reduced.

[0019] 3. By combining the information of the light source during the rule selection process, more physical meanings can be given to the sub-resolution auxiliary graphics, making the addition more reasonable and achieving better effects.

[0020] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can be obvious from the description, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the content specifically pointed out in the description and the drawings. Description of the Drawings

[0021] The drawings are only for the purpose of showing specific embodiments and are not considered as limiting the present invention. Throughout the drawings, the same reference signs represent the same components.

[0022] Figure 1 It is a flowchart of a method for adding auxiliary graphics based on a light source according to an embodiment of the present invention.

[0023] Figure 2Schematic diagram of a method for adding sub-resolution assist features based on light source factors according to another embodiment of the present invention;

[0024] Figure 3 Schematic diagram of characteristic parameters of a one-dimensional periodic structure according to an embodiment of the present invention;

[0025] Figure 4 Schematic diagram of characteristic parameters of the topography of an annular light source according to an embodiment of the present invention;

[0026] Figure 5 Schematic diagram of parameters of a sub-resolution assist feature addition rule according to an embodiment of the present invention.

[0027] Figure 6 Structural diagram of an apparatus for adding assist features based on a light source according to an embodiment of the present invention. Detailed implementation manners

[0028] The preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0029] A specific embodiment of the present invention discloses a method for adding assist features based on a light source. In the following, reference will be made to Figure 1 to describe in detail the method for adding assist features based on a light source according to an embodiment of the present invention.

[0030] In step S102, light source information of a reference light source and a list of assist feature addition rules corresponding to the reference light source are obtained. The light source information of the reference light source includes the shape distribution of the light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source. The list of assist feature addition rules is an original list of assist feature addition rules corresponding to the reference light source. The assist feature addition rules are stored in the original list of assist feature addition rules.

[0031] In step S104, when the light source information of the lithography light source is different from that of the reference light source, the sub-resolution assist feature addition rule is modified based on the light source information of the lithography light source to generate a modified sub-resolution assist feature addition rule list corresponding to the lithography light source. The light source information of the lithography light source includes the shape distribution of the light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source. Since the improvement of the lithography light source will cause the above light source information of the lithography light source to change. Therefore, when the lithography light source changes, modifying the sub-resolution assist feature addition rule based on the light source information of the lithography light source can generate a modified sub-resolution assist feature addition rule list corresponding to the lithography light source to reduce the complexity of sub-resolution assist feature addition and the cost of simulation requirements. The assist features described in this application are sub-resolution assist features, and these assist features are used to enhance the imaging effect of the target pattern but will not be transferred to the photoresist.

[0032] Specifically, modifying the sub-resolution assist features based on the lithography light source further includes: modifying the distribution and symmetry of the sub-resolution assist features according to the shape distribution of the lithography light source; assigning a modification weight or magnification to the sub-resolution assist feature addition rule according to the change in the sigma of the lithography light source; modifying the sub-resolution assist feature addition rule for different feature patterns according to the intensity distribution of the lithography light source; modifying the magnification of the sub-resolution assist feature addition rule according to the numerical aperture of the lithography light source; and modifying the sub-resolution assist feature addition rule for different directions according to the polarization direction of the lithography light source. Further, the modified sub-resolution assist feature addition rule is inversely correlated with the sigma or numerical aperture of the lithography light source. Specifically, when the sigma of the lithography light source increases, the period and distance in the corresponding modified sub-resolution assist feature addition rule decrease; or when the numerical aperture of the lithography light source increases, the period and distance in the corresponding modified sub-resolution assist feature addition rule decrease.

[0033] The modified sub-resolution assist feature addition rule is stored in the modified sub-resolution assist feature addition rule list. The modified sub-resolution assist feature addition rule includes the geometric information of the sub-resolution assist feature to be added, the addition position information, and the applicable condition information. Specifically, the geometric information includes the line length, width, and orientation of the sub-resolution assist feature to be added; the position information includes the relative distance between the sub-resolution assist feature to be added and the target pattern; and the applicable condition includes the scenario in which the modified sub-resolution assist feature addition rule is used.

[0034] In step S106, according to the modified auxiliary graphic addition rule list, obtain the auxiliary graphic addition rules for the layout, and add the auxiliary graphics to be added to the layout according to the auxiliary graphic addition rules for the layout. Specifically, obtaining the auxiliary graphic addition rules for the layout according to the modified auxiliary graphic addition rule list further includes: based on the geometric features of the target graphics in the layout, select the modified auxiliary graphic addition rules from the modified auxiliary graphic addition rule list, where the geometric features of the target graphics include: the length, width, and orientation of the target graphics, and the relative positions with other target graphics in the horizontal direction, vertical direction, and diagonal direction. In addition, when the geometric features of the target graphics are not in the modified auxiliary graphic addition rule list, use the nearest neighbor approximation method to perform weighted averaging on the modified auxiliary graphic addition rules of the graphics with geometric dimensions similar to those of the target graphics to obtain the auxiliary graphic addition rules for the layout.

[0035] Based on the geometric features of the target graphics in the layout, selecting the modified auxiliary graphic addition rules from the modified auxiliary graphic addition rule list further includes: Step 1, determine the core structure and its size of the target graphics; Step 2, classify the target graphics according to size, period, and surrounding graphic features, where the classified target graphics include one-dimensional line graphics and two-dimensional structures; Step 3, for the one-dimensional line graphics, according to the conditions defined in Step 1, select the modified auxiliary graphic addition rules in the direction parallel to the line as the auxiliary graphic addition rules for the layout; Step 4, for the two-dimensional structures, combined with the conditions defined in Step 1, select the modified auxiliary graphic addition rules in the direction parallel to the line, perpendicular direction, and diagonal direction as the auxiliary graphic addition rules for the layout.

[0036] After adding all the auxiliary graphics to be added to the layout, it further includes: performing conflict cleaning and mask manufacturing rule checking on the layout with the added auxiliary graphics to be added; and when both the conflict cleaning and mask manufacturing rule checking pass, output the layout.

[0037] Compared with the prior art, the embodiments of the present application re-explore with the change of the light source and the change of the core graphic size when developing towards more advanced nodes. In other words, modify the (sub-resolution) auxiliary graphic addition rules, thereby reducing the complexity of sub-resolution auxiliary graphic addition and saving computing resources and time costs. By generating the modified auxiliary graphic addition rule list corresponding to the lithography light source, the complexity of sub-resolution auxiliary graphic addition can be reduced and the cost of simulation requirements can be reduced.

[0038] Another specific embodiment of the present invention discloses a device for adding auxiliary graphics based on a light source, refer to Figure 6, The device for adding auxiliary graphics based on a light source includes: an initial information acquisition module 602, a rule modification module 604, a layout rule acquisition module 606, and an auxiliary graphics addition module 608. Specifically, hereinafter, reference will be made to Figure 6 , and each of the initial information acquisition module 602, the rule modification module 604, the layout rule acquisition module 606, and the auxiliary graphics addition module 608 will be described in detail.

[0039] The initial information acquisition module 602 is used to acquire the light source information of a reference light source and a list of auxiliary graphics addition rules corresponding to the reference light source. The rule modification module 604 is used to modify the auxiliary graphics addition rules based on the light source information of a lithography light source when the light source information of the lithography light source is different from that of the reference light source, so as to generate a modified list of auxiliary graphics addition rules corresponding to the lithography light source. The layout rule acquisition module 606 is used to acquire the auxiliary graphics addition rules for the layout according to the modified list of auxiliary graphics addition rules. The auxiliary graphics addition module 608 is used to add the auxiliary graphics to be added to the layout according to the auxiliary graphics addition rules for the layout.

[0040] Hereinafter, reference will be made to Figures 2 to 5 , and the method for adding auxiliary graphics based on a light source will be described in detail by taking specific examples.

[0041] In an alternative embodiment, for an initial layout, one or more auxiliary graphics addition rules are selected so that the selected auxiliary graphics addition rules match the lithography light source. For example, as Figure 2 shown, the method for adding auxiliary graphics based on a light source includes the following steps:

[0042] Step S1: Obtain an initial layout for which sub-resolution auxiliary graphics are to be added. The light source information refers to the shape distribution of the used light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source, etc. The layout applicable to the method for adding auxiliary graphics based on a light source provided in this embodiment can be all layout graphic structures such as one-dimensional periodic line structures, L-shaped structures, hole-shaped structures, T-shaped structures, etc. For example, please refer to Figure 3 , taking the layout for which sub-resolution auxiliary graphics are to be added as a one-dimensional periodic line graph as an example to illustrate the specific process of the sub-resolution auxiliary graphics addition method. The target graphic line width is W1, for example, W1 = 45 nm, and the period of the target graphic is P1, for example, P1 = 310 nm.

[0043] Step S2: For each target graphic in the initial layout, an auxiliary graphics addition rule is selected based on the geometric features of the target graphic. If the selected auxiliary graphics addition rule matches the light source information when lithographing the initial layout, sub-resolution auxiliary graphics are added to the target graphic according to the selected auxiliary graphics addition rule.

[0044] Step S3: Output the layout after the sub-resolution assist patterns of all target patterns are added.

[0045] Since the light source used for generating the rules may be different from the light source used for the target patterns, applying the rules to the target layout may affect its accuracy. The method for adding assist patterns based on the light source provided in this embodiment can endow the sub-resolution assist patterns with certain physical meanings by combining the light source information during the lithography of the initial layout in the process of rule selection, making the addition of sub-resolution assist patterns more reasonable and improving the accuracy of layout correction.

[0046] In an embodiment of the present application, a lithography light source for lithography layout is provided. The form of the lithography light source may be an annular light source, a secondary illumination light source, a four-level illumination light source, etc. Please refer to Figure 4 , taking the annular light source of the one-dimensional periodic line pattern in lithography as an example. The annular light source 301 is the light source used for lithography layout in this embodiment, with the ring width WA1, and the annular light source 302 is the light source used for generating the rules for adding the original assist patterns, with the ring width WA2. The ring widths of the two annular light sources are the same, that is, WA1 = WA2. The sigma of the annular light source 302 is slightly smaller than the sigma of the annular light source 301, and the difference is △S. For example, △S = 0.2. According to the proportion of △S occupying the central value of the original light source ring width, the Figure 5 characteristic parameters are corrected.

[0047] In an embodiment of the present invention, the assist pattern addition rule list includes the geometric information, addition position information, and applicable conditions of the sub-resolution assist patterns; the geometric information includes the line length, width, and orientation of the sub-resolution assist patterns, which refers to the positions where the patterns can be placed. In particular, for the sub-resolution assist patterns with a hole structure, it is necessary to clarify their positions in the main pattern, including horizontal positions, vertical positions, diagonal positions, etc. Specifically, the final form of the sub-resolution assist patterns is a rectangle, mainly considering the convenience of mask manufacturing. In the long run, the sub-resolution assist patterns can be non-rectangular. This embodiment takes the rectangular sub-resolution assist patterns as an example, and other patterns can be decomposed into rectangles. The position information includes the relative distance between the sub-resolution assist patterns and the target patterns; the applicable conditions include the geometric characteristics of the layout corresponding to the rules. The applicable conditions specify the geometric characteristics under which the target patterns can use this rule. For example, for the one-dimensional line patterns arranged periodically and repeatedly, the applicable conditions will include the line width and period range of the target patterns. Under this range, this rule is selected.

[0048] Specifically, this embodiment provides an assist pattern addition rule list. Please refer to Table 1 below.

[0049] Example of the rule list for adding auxiliary graphics in Table 1

[0050]

[0051] Note: pitch is the period of the target graphics, space is the distance between the adjacent sides of the SRAF to be added and the target graphics or the main graphics, and Width is the width of the corresponding sub-resolution auxiliary graphics. The unit of each parameter in the table is nm.

[0052] In step S2, when the geometric features of the layout are not in the rule list, for example, the period of the layout is 275 nm, which is between the first row and the second row of Table 1. According to the geometric features of the layout, select the rule closest to the applicable range from the rule list (for example, from Table 1, directly select the widths and spacings of the first SRAF, the second SRAF, etc. according to the graphic period (pitch)). Then apply it, that is, select the rule data of SRAF1 and SRAF2 in the first row and the second row, and combine the gap between the layout period and 260 nm and 280 nm to perform weighted average calculation. The calculated results are that the Space of SRAF1 is 69 nm and the Width is 25 nm; the Space of SRAF2 is 136 nm and the Width is 25 nm.

[0053] The geometric features of the layout include the period, length, width of the target graphics, and the arrangement angle of the periodic graphics (mainly referring to the graphic arrangement method, such as arranging in the X direction or the Y direction, or arranging at 45° or other angles), as well as the relative distances between adjacent target graphics in the horizontal direction, vertical direction, and diagonal direction.

[0054] Specifically, the period of the target graphics in the layout selected in this embodiment is 310 nm. Corresponding to the rule list in Table 1, there are reasons to choose both the periods of 300 nm and 320 nm. Due to the constraints of the mask manufacturing rules, generally, the rule with a smaller period will be selected for addition. In this embodiment, only considering the geometric features, the rule for adding sub-resolution auxiliary graphics corresponding to the 300 nm period is selected.

[0055] In step S3, according to the distribution of the light source and the sigma of the light source, it is judged whether the selected rule for adding auxiliary graphics matches the light source information. Generally, the light source sigma is related to the graphic period after adding the auxiliary graphics. After the center value of the light source sigma is fixed, the corresponding optimal graphic period is fixed. When changing the light source sigma, for example, when the center value of sigma increases, the spacing between the auxiliary graphics and the main graphics should be correspondingly reduced to achieve period matching.

[0056] Judge whether the distribution and symmetry of the sub-resolution assist patterns in the selected assist pattern addition rule are reasonable according to the distribution of the light source; and judge whether the relative position of the sub-resolution assist patterns in the selected assist pattern addition rule and the target pattern is reasonable according to the sigma of the light source. For example, when the light source is second-level illumination in the X direction and its sigma central value increases from 0.8 to 0.9, the space of the assist pattern perpendicular to the X direction should be reduced; when the light source changes from second-level illumination in the X direction to fourth-level illumination in the XY dual directions, the addition rule of the sub-resolution assist pattern in the Y direction should be modified; when the numerical aperture of the light source increases from 1.20 to 1.35, the rules of the sub-resolution assist patterns in all directions, especially the period rule, should be reduced.

[0057] Generally, the sub-resolution assist pattern rules corresponding to different light sources are different. In actual applications, the assist pattern addition rule table should be appropriately adjusted according to the changes in the light source characteristics. For example, if the light source sigma central value increases by 10%, the space and width of the corresponding sub-resolution assist patterns should be reduced by 10%; or be constrained by the optimal dimensions calculated according to the strict model.

[0058] Specifically, the sigma of the light source corresponding to the target pattern to which the sub-resolution assist pattern is to be added is 0.2 larger than the light source corresponding to the rule generation. In the one-dimensional periodic line structure, the period corresponding to the change in the number of sub-resolution assist patterns should be smaller. Under the light source corresponding to the target pattern, the distribution of the light intensity transmittance behind the mask will be closer to the pattern with a period of 320 nm. Therefore, to judge the rule corresponding to the selected period of 300 nm, a new rule needs to be selected. In this embodiment, the addition rule of the sub-resolution assist pattern with a period of 320 nm is selected.

[0059] Add the rule corresponding to the period of 320 nm to Figure 3 the layout shown. Please refer to Figure 5Taking Pitch = 320nm in the table as an example, the number of sub-resolution assist features shown in the table is the number of sub-resolution assist features between two target features 101 and 102. Among them, the sub-resolution assist feature 201 mainly acts on the target feature 101, the sub-resolution assist feature 203 mainly acts on the target feature 102, and the sub-resolution assist feature 202 acts on both the target feature 101 and 102 and is shared by both. Based on the target feature 101, the width (Width) of the sub-resolution assist feature 201 is SW1, SW1 = 25nm, and the space width (Space) between it and the target feature 101 is SS1, SS1 = 65nm; the width of the sub-resolution assist feature 202 is SW2, SW2 = 25nm, and the space width between it and the target feature 101 is SS2, SS2 = 125nm; the width of the sub-resolution assist feature 203 is SW3, SW3 = 25nm, and the space width between it and the target feature 101 is SS3, SS3 = 185nm.

[0060] Considering the symmetry of the features, adjust the sub-resolution assist features in the selected rules. The adjustment methods include: symmetry constraint, adjacent feature conflict constraint, adjacent feature minimum size constraint, etc. Add the adjusted sub-resolution assist features to the layout.

[0061] Specifically, since there are only two applicable rules in this embodiment, the addition rule of the sub-resolution assist features with a final usage period of 320nm is determined. During the addition process, considering the feature symmetry, in the final addition result, the widths of the sub-resolution assist features 201, 202, and 203 are equal, that is, SW1 = SW2 = SW3 = 25nm. The space width between the sub-resolution assist feature 201 and the target feature 101 is SS1, SS1 = 65nm; the space width between the sub-resolution assist feature 202 and the target feature 101 is SS2, SS2 = 120nm; the space width between the sub-resolution assist feature 203 and the target feature 101 is SS3, SS1 = 175nm. By considering symmetry, it can be ensured that all the sub-resolution assist features that play a major role adjacent to the target feature have the same relative position, and the centrally shared sub-resolution assist feature is located at the center position between two adjacent target features, that is, SS1 = SS4 = 65nm, SS2 = SS5 = 120nm.

[0062] Furthermore, it also includes outputting the layout with the sub-resolution assist features added.

[0063] Specifically, the output layout should include the target feature or the main feature, and the added sub-resolution assist features.

[0064] Preferably, after outputting the layout with sub-resolution assist features added, it further includes performing conflict cleaning and mask manufacturing rule checking on the layout with sub-resolution assist features added. Specifically, conflict cleaning means that if the sub-resolution assist features of adjacent main features overlap or the distance is less than the specified size, the redundant sub-resolution features need to be deleted, or the width and spacing need to be adjusted. Mask manufacturing rule checking mainly performs mask manufacturing-oriented checks on the above-added and cleaned sub-resolution assist features, including checking the minimum size, minimum area, minimum spacing, minimum step width, etc. of the sub-resolution assist features.

[0065] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0066] 1. In the embodiments of the present application, when developing towards more advanced nodes, the rules for adding sub-resolution assist features are re-explored with the change of the light source and the change of the core feature size.

[0067] 2. By generating a list of modified assist feature addition rules corresponding to the lithography light source, the complexity of adding sub-resolution assist features and the cost of simulation requirements can be reduced.

[0068] 3. By combining the information of the light source in the process of rule selection, more physical meanings can be given to the sub-resolution assist features, making the addition more reasonable and achieving better effects.

[0069] In the above description, technical details such as the layout of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of the required shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. In addition, although the above embodiments are described separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0070] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for adding auxiliary graphics based on a light source, characterized in that, Including: Obtain the light source information of a reference light source and a list of auxiliary pattern addition rules corresponding to the reference light source, where the auxiliary pattern is a sub-resolution auxiliary pattern; When the light source information of the lithography light source is different from the light source information of the reference light source, modify the auxiliary pattern addition rules based on the light source information of the lithography light source to generate a modified list of auxiliary pattern addition rules corresponding to the lithography light source. The light source information of the lithography light source includes the shape distribution of the light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source. Modifying the sub-resolution auxiliary pattern addition rules based on the lithography light source further includes: modifying the distribution and symmetry of the sub-resolution auxiliary pattern according to the shape distribution based on the lithography light source; assigning a modification weight or magnification to the auxiliary pattern addition rules according to the change in the sigma of the lithography light source; modifying the auxiliary pattern addition rules for different feature patterns according to the intensity distribution of the lithography light source; modifying the magnification of the auxiliary pattern addition rules according to the numerical aperture of the lithography light source; and modifying the auxiliary pattern addition rules in different directions according to the polarization direction of the lithography light source; and Obtain the auxiliary pattern addition rules for the layout according to the modified list of auxiliary pattern addition rules and add the auxiliary patterns to be added to the layout according to the auxiliary pattern addition rules for the layout.

2. The method for adding an auxiliary pattern based on a light source according to claim 1, wherein The modified auxiliary pattern addition rules are inversely correlated with the sigma or numerical aperture of the lithography light source, where When the sigma of the lithography light source increases, the period and distance in the corresponding modified auxiliary pattern addition rules decrease; or When the numerical aperture of the lithography light source increases, the period and distance in the corresponding modified auxiliary pattern addition rules decrease.

3. The method for adding an auxiliary pattern based on a light source according to claim 1, wherein The modified auxiliary pattern addition rules are stored in the modified list of auxiliary pattern addition rules. The modified auxiliary pattern addition rules include the geometric information, addition position information, and applicable condition information of the sub-resolution auxiliary pattern to be added; where The geometric information includes the line length, width, and orientation of the sub-resolution auxiliary pattern to be added; The position information includes the relative distance between the sub-resolution auxiliary pattern to be added and the target pattern; The applicable conditions include the scenarios in which the modified auxiliary pattern addition rules are used.

4. The method for adding an auxiliary pattern based on a light source according to claim 1, characterized in that Obtaining the auxiliary pattern addition rules for the layout according to the modified list of auxiliary pattern addition rules further includes: Selecting the modified auxiliary pattern addition rules from the modified list of auxiliary pattern addition rules based on the geometric features of the target pattern in the layout, where the geometric features of the target pattern include: the length, width, and orientation of the target pattern, and the relative positions with other target patterns in the horizontal, vertical, and diagonal directions.

5. The method for adding an auxiliary pattern based on a light source according to claim 4, wherein Selecting the modified auxiliary pattern addition rules from the modified list of auxiliary pattern addition rules based on the geometric features of the target pattern in the layout further includes: Step 1, determine the core structure and its size of the target pattern; Step 2: Classify the target graphics according to the size, period, and surrounding graphic features. Among them, the classified target graphics include one-dimensional line graphics and two-dimensional structures; Step 3: For the one-dimensional line graphics, according to the conditions defined in Step 1, select the modified auxiliary graphic addition rule in the direction parallel to the line as the auxiliary graphic addition rule for the layout; Step 4: For two-dimensional structures, in combination with the conditions defined in Step 1, select the modified auxiliary graphic addition rule in the direction parallel to the line, the perpendicular direction, and the diagonal direction as the auxiliary graphic addition rule for the layout.

6. The method for adding an auxiliary pattern based on a light source according to claim 3, wherein Among them, Obtaining the auxiliary graphic addition rule for the layout according to the modified auxiliary graphic addition rule list further includes: When the geometric features of the target graphic are not in the modified auxiliary graphic addition rule list, use the nearest neighbor approximation method to perform weighted averaging on the modified auxiliary graphic addition rules of the graphics with geometric dimensions similar to those of the target graphic to obtain the auxiliary graphic addition rule for the layout.

7. The method for adding an auxiliary pattern based on a light source according to any one of claims 1 to 6, characterized in that, After adding all the auxiliary graphics to be added to the layout, it further includes: Performing conflict cleaning and mask manufacturing rule checking on the layout to which the auxiliary graphics to be added have been added; and When both the conflict cleaning and the mask manufacturing rule checking pass, output the layout.

8. A device for adding auxiliary graphics based on a light source, characterized in that, It includes: An initial information acquisition module, a rule modification module, a layout rule acquisition module, and an auxiliary graphic addition module. Among them, The initial information acquisition module is used to acquire the light source information of the reference light source and the auxiliary graphic addition rule list corresponding to the reference light source. Among them, the auxiliary graphic is a sub-resolution auxiliary graphic; The rule modification module is used to, when the light source information of the lithography light source is different from the light source information of the reference light source, modify the auxiliary graphic addition rule based on the light source information of the lithography light source to generate a modified auxiliary graphic addition rule list corresponding to the lithography light source. Among them, the light source information of the lithography light source includes the shape distribution of the light source, the sigma of the light source, the intensity distribution of the light source, the numerical aperture of the light source, and the polarization direction of the light source. Modifying the sub-resolution auxiliary graphic addition rule based on the lithography light source further includes: modifying the distribution and symmetry of the sub-resolution auxiliary graphic according to the shape distribution of the lithography light source; assigning a modification weight or magnification to the auxiliary graphic addition rule according to the change of the sigma of the lithography light source; modifying the auxiliary graphic addition rules for different feature graphics according to the intensity distribution of the lithography light source; modifying the magnification of the auxiliary graphic addition rule according to the numerical aperture of the lithography light source; and modifying the auxiliary graphic addition rules in different directions according to the polarization direction of the lithography light source; and The layout rule acquisition module is used to obtain the auxiliary graphic addition rule for the layout according to the modified auxiliary graphic addition rule list; The auxiliary graphic addition module is used to add the auxiliary graphics to be added to the layout according to the auxiliary graphic addition rule for the layout.

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