Mask and method of designing the same

Abstract

Embodiments of the present application provide a mask and a design method thereof. In the mask provided by the embodiments of the present application, for a pattern array including at least two target patterns, since each corner of each target pattern is provided with at least one second auxiliary pattern having an acute angle or an obtuse angle with a straight line on which a side of the second auxiliary pattern lies, and a distance between the second auxiliary pattern and an adjacent corner is less than a distance between a first auxiliary pattern and an adjacent side, the arrangement density of the auxiliary patterns near the corner can be improved, so that the light intensity distribution near the corner of the target pattern in the exposure process can be improved, the degree of rounding of the corner can be reduced, and the matching degree of a pattern formed by a photoresist layer after exposure and the target pattern can be improved. Meanwhile, the arrangement density of the auxiliary patterns in the periphery of each target pattern can be increased, the focusing depth in the exposure process can be increased, and the matching degree of the pattern formed by the photoresist layer after exposure and the target pattern can be further improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more specifically, to a photomask and its design method. Background Technology

[0002] In the photolithography process for manufacturing semiconductor devices, a photomask is used to transfer the target pattern on the photomask to the film layer to be etched on the substrate.

[0003] As the size of semiconductor devices decreases, the diffraction effect of light becomes increasingly significant, leading to a greater difference between the pattern formed on the etched film and the target pattern. In particular, due to the OPE (Optical Proximity Effect), the pattern formed on the etched film exhibits obvious problems such as rounded corners and contracted straight ends.

[0004] Currently, the main method to reduce the difference between the pattern formed on the etched film and the target pattern is through OPC (Optical Proximity Correction) technology. However, existing OPC technology still has difficulty solving the problem of obvious corner rounding of the pattern formed on the etched film. Summary of the Invention

[0005] This application addresses the shortcomings of existing methods by proposing a photomask and its design method to solve the technical problem of obvious rounded corners in the pattern formed on the etched film layer during the photolithography process of existing technologies.

[0006] In a first aspect, embodiments of this application provide a photomask, comprising:

[0007] At least two target graphics, each target graphic comprising at least two corners and at least two sides;

[0008] At least two first auxiliary combined graphics, each first auxiliary combined graphics surrounding a target graphic, the first auxiliary combined graphics including at least two first auxiliary graphics and at least two second auxiliary graphics; a first auxiliary graphic is provided on the outer side of each side, the first auxiliary graphic being parallel to the adjacent side; a second auxiliary graphic is provided on the outer side of each corner, the angle between the line containing the second auxiliary graphic and the line containing the side is an acute angle or an obtuse angle; the distance between the second auxiliary graphic and the adjacent corner is less than the distance between the first auxiliary graphic and the adjacent side;

[0009] At least one second auxiliary combination graphic surrounds all the first auxiliary combination graphics.

[0010] Secondly, embodiments of this application provide a mask design method as provided in the first aspect, comprising:

[0011] Determine whether the distance between any two adjacent target graphics is less than a set threshold.

[0012] If the value is less than a set threshold, then each target graphic is determined to be surrounded by at least one first auxiliary combined graphic, and all first auxiliary combined graphics are surrounded by at least one second auxiliary combined graphic.

[0013] The beneficial technical effects of the technical solutions provided in this application include:

[0014] In the mask provided in this application embodiment, for a pattern array including at least two target patterns, since each target pattern has at least one second auxiliary pattern at its corner that forms an acute or obtuse angle with the straight line containing the side, and the distance between the second auxiliary pattern and the adjacent corner is less than the distance between the first auxiliary pattern and the adjacent side, the arrangement density of the auxiliary patterns near the corner can be increased. This helps to improve the light intensity distribution near the corner of the target pattern during the exposure process, which is beneficial to reduce the rounding degree of the corner and improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern.

[0015] Meanwhile, by surrounding each target pattern with at least one first auxiliary combination pattern and setting a second auxiliary combination pattern surrounding all the first auxiliary combination patterns, the arrangement density of the auxiliary patterns around each target pattern can be increased, the focus depth during the exposure process can be increased, and the matching degree between the pattern formed on the etched film layer after exposure and the target pattern can be further improved.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0018] Figure 1 This is a schematic diagram of a graphic design scheme in a photomask provided in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of another graphic design scheme in a photomask provided in an embodiment of this application;

[0020] Figure 3a Provided for the embodiments of this application Figure 1 Simulated pattern of the target pattern located at the center of the array formed on the photoresist layer, simulated pattern formed by the pattern design scheme in related technologies, and comparison image of the target pattern;

[0021] Figure 3b Provided for the embodiments of this application Figure 1 A simulated pattern of the target pattern located between the two corners of the array edge formed on the photoresist layer, a simulated pattern formed by the pattern design scheme in related technologies, and a comparison image of the target pattern;

[0022] Figure 3c Provided for the embodiments of this application Figure 1 Simulated pattern of the target pattern located at the corner of the array formed on the photoresist layer, simulated pattern formed by the pattern design scheme in related technologies, and comparison image of the target pattern;

[0023] Figure 3d Provided for the embodiments of this application Figure 1 A comparison of errors between simulated images formed by photoresist layers of target patterns located at the corners of the array and simulated images formed by pattern design schemes in related technologies at different defocus distances;

[0024] Figure 4 A schematic flowchart illustrating a mask design method provided in an embodiment of this application;

[0025] Figure 5 In a mask design method provided in this application embodiment, after determining that the distance between any two adjacent target graphics is greater than a set threshold, a schematic diagram of the arrangement relationship between a single target graphic and multiple first auxiliary graphics is provided.

[0026] Figure 6 Provided for the embodiments of this application Figure 5 The diagram shows an exposure simulation of a single target graphic and multiple first auxiliary graphics.

[0027] Figure 7 In a mask design method provided in this application embodiment, after determining that the spacing between any two adjacent target graphics is greater than a set threshold, an alternative arrangement relationship of a single target graphic and multiple first auxiliary graphics is shown in the schematic diagram.

[0028] Explanation of reference numerals in the attached figures:

[0029] 10-Target graphic;

[0030] 11-Side; 12-Corner;

[0031] 20 - First auxiliary combination graphic;

[0032] 21-First auxiliary graphic; 211-Sub-segment; 22-Second auxiliary graphic;

[0033] 30 - Second auxiliary combination graphics;

[0034] 31 - Third auxiliary figure; 32 - Fourth auxiliary figure;

[0035] 40 - Fifth auxiliary graphic;

[0036] 101 - Simulated graphics formed by related graphic design schemes;

[0037] 102 - A simulated pattern formed on the photoresist layer by the target pattern located at the center of the array;

[0038] 103 - The target pattern located at the edge of the array and between the two corners is formed in the photoresist layer.

[0039] Simulated graphics;

[0040] 104 - A simulated pattern formed on the photoresist layer by the target pattern located at the corner of the array;

[0041] 105 - A simulated pattern formed on a photoresist layer of a single target pattern and multiple first auxiliary patterns. Detailed Implementation

[0042] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0043] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the word “comprising” as used in the specification of this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude other features, information, data, steps, operations, elements, components, and / or combinations thereof supported by the art. The term “and / or” as used herein refers to at least one of the items defined by the term; for example, “A and / or B” can be implemented as “A,” or as “B,” or as “A and B.”

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0045] First, let's introduce and explain several terms used in this application:

[0046] In semiconductor manufacturing, patterning processes are used to transfer designs to the surface of a substrate to be etched. Currently, patterning processes mainly include exposure, development, and etching steps. In the exposure step, light passes through the transparent area of ​​a photomask and illuminates the photoresist-coated substrate, causing a chemical reaction in the photoresist. In the development step, the different solubility of the developer in the photoresist and the non-photoresist is utilized to form a photolithographic pattern, transferring the pattern from the photomask to the photoresist. In the etching step, the photolithographic pattern formed by the photoresist layer is etched onto the substrate, further transferring the pattern from the photomask to the substrate.

[0047] As the size of the target pattern continues to decrease, the diffraction effect of light becomes more and more obvious, resulting in the OPE problem. This causes the actual lithographic pattern formed to be severely distorted relative to the design pattern on the mask, ultimately leading to a difference between the actual pattern formed by photolithography on the film layer to be etched and the target pattern.

[0048] Currently, OPC is mainly used to offset OPE by setting auxiliary patterns around the target pattern. However, existing OPC technology still has difficulty solving the problem of obvious corner rounding in the pattern formed on the etched film layer. At the same time, the density of the photomask pattern (including the target pattern and auxiliary pattern) in the existing photomask is relatively small, resulting in insufficient DOF (Depth of Focus) of the photomask pattern density, which further leads to the difference between the actual pattern formed on the etched film layer after photolithography and the target pattern.

[0049] The photomask and its design method provided in this application are intended to solve the above-mentioned technical problems of the prior art.

[0050] The technical solution of this application and how it solves the above-mentioned technical problems are described in detail below with specific embodiments. It should be noted that the following embodiments can be referenced, learned from, or combined with each other, and the same terms, similar features, and similar implementation steps in different embodiments will not be described again.

[0051] This application provides a photomask, and a schematic diagram of a graphic design scheme in the photomask is shown below. Figure 1As shown, it includes: at least two target graphics 10, each target graphic 10 including at least two corners 12 and at least two sides 11; at least two first auxiliary combination graphics 20, each first auxiliary combination graphics 20 surrounding a target graphic 10, each first auxiliary combination graphics 20 including at least two first auxiliary graphics 21 and at least two second auxiliary graphics 22; a first auxiliary graphic 21 is disposed on the outer side of each side 11, the first auxiliary graphic 21 being parallel to the adjacent side 11; a second auxiliary graphic 22 is disposed on the outer side of each corner 12, the angle between the line containing the second auxiliary graphic 22 and the line containing the side 11 being an acute or obtuse angle; the distance between the second auxiliary graphic 22 and the adjacent corner 12 is less than the distance between the first auxiliary graphic 11 and the adjacent side 11; at least one second auxiliary combination graphics 30 surrounding all the first auxiliary combination graphics 20.

[0052] In the mask provided in this application embodiment, for a pattern array including at least two target patterns 10, since each target pattern 10 has at least one second auxiliary pattern 22 at its corner 12, which forms an acute or obtuse angle with the straight line containing the side 11, and the distance between the second auxiliary pattern 22 and the adjacent corner 12 is less than the distance between the first auxiliary pattern 21 and the adjacent side 11, the arrangement density of the auxiliary patterns near the corner 12 can be increased. Thus, during the exposure process, it helps to improve the light intensity distribution near the corner 12 of the target pattern 10, which is beneficial to reduce the rounding degree of the corner 12, and can improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0053] Meanwhile, by surrounding each target pattern 10 with at least one first auxiliary combined pattern 20 and setting a second auxiliary combined pattern 30 surrounding all the first auxiliary combined patterns 20, the arrangement density of the auxiliary patterns around each target pattern 10 can be increased, which helps to increase the focus depth during the exposure process, improves the lithography process window, and further improves the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0054] In this embodiment of the application, the mask includes at least two target patterns 10, optionally, such as Figure 1 As shown, the mask includes nine target graphics 10, which are arranged in an array.

[0055] In this embodiment of the application, each target graphic 10 includes at least two corners 12 and at least two sides 11. Optionally, as shown... Figure 1 As shown, the target graphic 10 is square in shape and includes four corners 12 and four sides 11.

[0056] In the embodiments of this application, such as Figure 1As shown, each target graphic 10 is surrounded by a first auxiliary combined graphic 20, that is, the number of target graphics 10 and the number of first auxiliary combined graphics 20 are the same.

[0057] In the embodiments of this application, such as Figure 1 As shown, the first auxiliary combination graphic 20 includes at least two first auxiliary graphics 21 and at least two second auxiliary graphics 22. The first auxiliary graphics 21 are parallel to the adjacent side 11, and the angle between the line containing the second auxiliary graphics 22 and the line containing the side 11 is an acute angle or an obtuse angle.

[0058] Optionally, such as Figure 1 As shown, for the same target graphic 10, a first auxiliary graphic 21 is provided on the outer side of each side 11, that is, the number of first auxiliary graphics 21 is the same as the number of sides 11; a second auxiliary graphic 22 is provided on the outer side of each corner 12, that is, the number of second auxiliary graphics 22 is the same as the number of corners 12.

[0059] In this embodiment, the distance between the second auxiliary graphic 22 and the adjacent corner 12 is less than the distance between the first auxiliary graphic 11 and the adjacent side 11. It should be noted that, unless otherwise specified, in this embodiment, the distances refer to the shortest distance between the two.

[0060] In this embodiment, by providing at least one second auxiliary pattern 22 at each corner 12 of the target pattern 10, and the distance between the second auxiliary pattern 22 and the adjacent corner 12 is less than the distance between the first auxiliary pattern 21 and the adjacent side 11, the arrangement density of the auxiliary patterns near the corner 12 can be increased. During the exposure process, the second auxiliary pattern 22 can offset part of the OPE, thereby helping to improve the light intensity distribution near the corner 12 of the target pattern 10, which is beneficial to reducing the rounding degree of the corner 12, and can improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0061] In the embodiments of this application, such as Figure 1 As shown, the array pattern formed by all the first auxiliary combination patterns 20 is surrounded by at least one second auxiliary combination pattern 30, which can further increase the arrangement density of the auxiliary patterns around the target pattern 10, help increase the depth of field of the pattern in the mask, help improve the focusing depth of the light from the lithography machine after passing through the mask to reach the photoresist layer, and thus help further improve the matching degree between the pattern formed on the film layer to be etched after exposure and the target pattern 10.

[0062] Optionally, such as Figure 1 As shown, the array pattern formed by all the first auxiliary combination patterns 20 is surrounded by two second auxiliary combination patterns 30.

[0063] Those skilled in the art can determine the specific number of the first auxiliary combination graphic 20 and the second auxiliary combination graphic 30 based on the parameter information of the target graphic 10.

[0064] It should be noted that in this embodiment, the target pattern 10, the first auxiliary pattern 21, and the second auxiliary pattern 22 are all light-transmitting areas. Optionally, the target pattern 10, the first auxiliary pattern 21, and the second auxiliary pattern 22 are through holes penetrating the photomask.

[0065] Optionally, such as Figure 1 As shown, in one embodiment of this application, the first auxiliary combined graphic 20 is concentrically arranged with the target graphic 10 it surrounds; the first auxiliary combined graphic 20 is a non-closed ring, and the first auxiliary graphic 21 and the second auxiliary graphic 22 are arranged alternately along the direction surrounding the target graphic 10; the length of the first auxiliary graphic 21 is less than the length of the side 11.

[0066] In the embodiments of this application, such as Figure 1 As shown, the first auxiliary combined pattern 20 is concentrically arranged with the target pattern 10 it surrounds, so that the distance between each side 11 of the target pattern 10 and the adjacent first auxiliary pattern 21 is the same, which helps to ensure the consistency of the arrangement density of the first auxiliary pattern 21 near each side 11 of the target pattern 10; and the distance between each corner 12 of the target pattern 10 and the adjacent second auxiliary pattern 22 is the same, which helps to ensure the consistency of the arrangement density of the second auxiliary pattern 22 near each corner 12 of the target pattern 10, and helps to reduce the rounding of each corner 12 to the same degree, which helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0067] In the embodiments of this application, such as Figure 1 As shown, along the direction surrounding the target graphic 10, the first auxiliary graphic 21 and the second auxiliary graphic 22 are arranged alternately to form a non-closed ring-shaped first auxiliary combination graphic 20.

[0068] Optionally, such as Figure 1 As shown, the length of the first auxiliary pattern 21 is less than the length of the side 11, which helps to ensure the length of the second auxiliary pattern 22, helps to ensure the density of the auxiliary patterns near the corner 12 of the target pattern 10, thus helping to improve the light intensity distribution near the corner 12, which is beneficial to reduce the rounding degree of the corner 12, and can improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0069] Optionally, such as Figure 1As shown, in one embodiment of this application, the second auxiliary combination pattern 30 includes at least two third auxiliary patterns 31 and at least two fourth auxiliary patterns 32; in the array formed by all the first auxiliary combination patterns 20, the third auxiliary pattern 31 is disposed outside the outermost first auxiliary pattern 21, and the fourth auxiliary pattern 32 is disposed outside the second auxiliary pattern 22 located at the corner; the third auxiliary pattern 31 is parallel to the adjacent first auxiliary pattern 21, and the fourth auxiliary pattern 32 is parallel to the adjacent second auxiliary pattern 22.

[0070] In the embodiments of this application, such as Figure 1 As shown, the second auxiliary combined graphic 30 includes multiple third auxiliary graphics 31 and multiple fourth auxiliary graphics 32. The third auxiliary graphics 31 are parallel to the adjacent first auxiliary graphics 21, and the fourth auxiliary graphics 32 are parallel to the adjacent second auxiliary graphics 22, so that the shape of the second auxiliary combined graphic 30 is the same as the shape of the first auxiliary combined graphic 20.

[0071] Optionally, such as Figure 1 As shown, for the array formed by all the first auxiliary combination patterns 20, a third auxiliary pattern 31 is provided outside each of the outermost first auxiliary patterns 21, that is, the number of third auxiliary patterns 31 is the same as the number of the outermost first auxiliary patterns 21; a fourth auxiliary pattern 32 is provided outside the second auxiliary pattern 22 located at the corner, that is, the number of fourth auxiliary patterns 32 is the same as the number of the second auxiliary patterns 22 located at the corner.

[0072] Optionally, such as Figure 1 As shown, for the array formed by the nine first auxiliary combination patterns 20, the second auxiliary combination pattern 30 includes twelve third auxiliary patterns 31 and four fourth auxiliary patterns 32.

[0073] Those skilled in the art understand that, for an array formed by multiple target graphics 10, the target graphics 10 located in the central part and the first auxiliary combination graphics 20 of the adjacent target graphics 10 are close to each other, thereby ensuring the arrangement density of the auxiliary graphics near the target graphics 10 in the central part. However, the corners 12 and sides 11 of the target graphics 10 located at the corners and the outermost part cannot be close to the first auxiliary combination graphics 20 of the adjacent target graphics 10, resulting in the arrangement density of the auxiliary graphics near the corners and the outermost part of the target graphics 10 being less than the arrangement density of the auxiliary graphics near the target graphics 10 in the central part.

[0074] In this embodiment, a fourth auxiliary pattern 32 is provided on the outside of the second auxiliary pattern 22 located at the corner. Since the fourth auxiliary pattern 32 is parallel to the second auxiliary pattern 22, the arrangement density of the auxiliary patterns near the outer corner 12 of the target pattern 10 located at the corner can be further increased. During the exposure process, it helps to improve the light intensity distribution near the corner 12 of the target pattern 10, which is beneficial to reduce the rounding degree of the corner 12 and can improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0075] In this embodiment, by providing a third auxiliary pattern 31 on the outside of each of the outermost first auxiliary patterns 21, the arrangement density of auxiliary patterns near the outermost side 11 of the outermost target pattern 10 can be further increased. During the exposure process, this helps to increase the focusing depth of light reaching the photoresist layer after passing through the side 11, and can further improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0076] It should be noted that, in this embodiment, the third auxiliary pattern 31 and the fourth auxiliary pattern 32 in the second auxiliary combined pattern 30 are both light-transmitting areas. Optionally, the third auxiliary pattern 31 and the fourth auxiliary pattern 32 are through holes penetrating the photomask.

[0077] Optionally, such as Figure 1 As shown, in one embodiment of this application, all second auxiliary combination patterns 30 are non-closed rings; the second auxiliary combination patterns 30 are concentrically arranged with the array surrounding them; in the same second auxiliary combination pattern 30, the fourth auxiliary pattern 32 is spaced apart from the adjacent third auxiliary pattern 31, and any two adjacent fourth auxiliary patterns 32 are spaced apart; the length of the third auxiliary pattern 31 is greater than the length of the side 11.

[0078] In the embodiments of this application, such as Figure 1 As shown, all the second auxiliary combination graphics 30 are non-closed loops. Optionally, as... Figure 1 As shown, along the direction of the array formed around all the first auxiliary combination patterns 20, every three third auxiliary patterns 31 and one fourth auxiliary pattern 32 are arranged alternately.

[0079] In the embodiments of this application, such as Figure 1 As shown, the second auxiliary combined graphic 30 is concentrically arranged with the array surrounding it, i.e. Figure 1As shown, the center of the second auxiliary combined pattern 30 overlaps with the center of the target pattern 10 located in the middle and the center of the first auxiliary combined pattern 10 located in the middle. This ensures that the distance between each third auxiliary pattern 31 and its adjacent side 11 is equal, and the distance between each fourth auxiliary pattern 32 and its adjacent corner 12 is equal. This helps to ensure the consistency of the arrangement density of auxiliary patterns near each corner 12 in the target pattern 10, helps to ensure that the degree of reduction in the rounding of each corner 12 is the same, and helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0080] Optionally, such as Figure 1 As shown, in the same second auxiliary combination pattern 30, the fourth auxiliary pattern 32 and the adjacent third auxiliary pattern 31 are spaced apart, and any two adjacent fourth auxiliary patterns 32 are spaced apart, so that the second auxiliary combination pattern 30 forms a non-closed ring.

[0081] Optionally, such as Figure 1 As shown, the length of the third auxiliary pattern 31 is greater than the length of the side 11, so that the third auxiliary pattern 31 can increase the density of the auxiliary pattern near the corner 12 of the target pattern 10 located on the outermost side and between two adjacent corners, which helps to further reduce the rounding of each corner 12 to the same degree, and helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0082] Optionally, in any two adjacent second auxiliary combination patterns 30, the length of the third auxiliary pattern 31 of the outer second auxiliary combination pattern 30 is greater than the length of the third auxiliary pattern 31 of the inner second auxiliary combination pattern 30; the length of the fourth auxiliary pattern 32 of the outer second auxiliary combination pattern 30 is greater than the length of the fourth auxiliary pattern 32 of the inner second auxiliary combination pattern 30.

[0083] Optionally, such as Figure 1 As shown, in one embodiment of this application, in the outermost second auxiliary combination pattern 30, a third auxiliary pattern 31 is provided between any two adjacent fourth auxiliary patterns 32, and the length of the third auxiliary pattern 31 is greater than the length of the third auxiliary pattern 31 in the adjacent second auxiliary combination pattern 30.

[0084] In the embodiments of this application, such as Figure 1 As shown, in the outermost second auxiliary combination graphic 30, a third auxiliary graphic 31 is positioned between any two adjacent fourth auxiliary graphics 32. Optionally, as... Figure 1 As shown, the outermost second auxiliary combination graphic 30 includes four third auxiliary graphics 31 and four fourth auxiliary graphics 32.

[0085] In this embodiment, the length of the third auxiliary graphic 31 of the outermost second auxiliary combination graphic 30 is greater than the length of the third auxiliary graphic 31 in the adjacent second auxiliary combination graphic 30, thereby simplifying the design of the outermost second auxiliary combination graphic 30 and helping to reduce the production cost of the mask.

[0086] Optionally, such as Figure 1 As shown, the length of the third auxiliary pattern 31 of the outermost second auxiliary combination pattern 30 is greater than the sum of the lengths of all the third auxiliary patterns 31 on the same side in the adjacent second auxiliary combination pattern 30. This helps to ensure the arrangement density of the auxiliary patterns around the target pattern 10, helps to further reduce the rounding of each corner 12 to the same degree, and helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0087] Optionally, such as Figure 2 As shown, in one embodiment of this application, the second auxiliary combination pattern 30, except for the outermost second auxiliary combination pattern 30, is a non-closed ring; the second auxiliary combination pattern 30 is concentrically arranged with the array surrounding it; in the same non-closed ring second auxiliary combination pattern 30, each end of the fourth auxiliary pattern 32 is connected to a third auxiliary pattern 31, and any two adjacent third auxiliary patterns 31 are spaced apart; the length of the third auxiliary pattern 31 is greater than the length of the side 11.

[0088] In this embodiment, the second auxiliary combined pattern 30, excluding the outermost second auxiliary combined pattern 30, is a non-closed ring. Optionally, as... Figure 2 As shown, there are two second auxiliary combination graphics 30, and the second auxiliary combination graphics 30 located on the inner side is a non-closed ring.

[0089] Optionally, such as Figure 2 As shown, the second auxiliary combined graphic 30 is concentrically arranged with the array surrounding it, i.e. Figure 2 As shown, the center of the second auxiliary combined pattern 30 overlaps with the center of the target pattern 10 located in the middle and the center of the first auxiliary combined pattern 10 located in the middle. This helps to ensure the consistency of the arrangement density of auxiliary patterns near each corner 12 in the target pattern 10, helps to reduce the rounding of each corner 12 to the same degree, and helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0090] Optionally, such as Figure 2As shown, in the same non-closed ring second auxiliary combination pattern 30, any two adjacent third auxiliary patterns 31 are spaced apart, and the length of the third auxiliary pattern 31 is greater than the length of the side 11. This allows the third auxiliary pattern 31 to increase the density of auxiliary patterns near the corner 12 and side 11 of the outermost target pattern 10, which helps to further reduce the rounding degree of the corner 12 and increase the focusing depth of light reaching the photoresist layer after passing through the side 11. This helps to ensure the consistency of each corner in the pattern formed on the etched film layer after exposure.

[0091] Optionally, such as Figure 2 As shown, in the second auxiliary combination graphic 30 of the same non-closed ring, the two ends of the fourth auxiliary graphic 32 are connected to a third auxiliary graphic 31, which can further increase the density of auxiliary graphics near the outermost corner 12 of the target graphic 10 located at the corner, and help to further reduce the degree of rounding of each corner 12.

[0092] Optionally, such as Figure 2 As shown, in one embodiment of this application, in the outermost second auxiliary combination pattern 30, all the third auxiliary patterns 31 and the fourth auxiliary patterns 32 are connected to form a closed ring.

[0093] In this embodiment, for the outermost second auxiliary combination pattern 30, all the third auxiliary patterns 31 and all the fourth auxiliary patterns 32 are connected to form a closed loop along the direction of the array formed around all the first auxiliary combination patterns 20, thereby simplifying the design of the outermost second auxiliary combination pattern 30 and helping to reduce the production cost of the photomask.

[0094] Moreover, for the second auxiliary combination pattern 30 in a closed ring, it can increase the arrangement density of auxiliary patterns around the target pattern 10, which helps to further reduce the rounding of each corner 12 to the same degree, and helps to ensure the consistency of each corner in the pattern formed on the film layer to be etched after exposure.

[0095] Optionally, such as Figure 2 As shown, in one embodiment of this application, the first auxiliary graphic 21 includes two spaced segments 211; in the same first auxiliary combined graphic 20, one end of the second auxiliary graphic 22 is connected to one end of a segment 211 of one first auxiliary graphic 21, and the other end of the second auxiliary graphic 22 is connected to one end of a segment 211 of another first auxiliary graphic 21.

[0096] In the embodiments of this application, such as Figure 2 As shown, the first auxiliary graphic 21 includes two segments 211 spaced apart. For the same first auxiliary graphic 21, the lines containing the two segments 211 overlap each other.

[0097] In the embodiments of this application, such as Figure 2 As shown, in the same first auxiliary combination pattern 20, one end of each second auxiliary pattern 22 is connected to a sub-segment 211. Optionally, one end of the second auxiliary pattern 22 is connected to one end of a sub-segment 211 of a first auxiliary pattern 21, and the other end of the second auxiliary pattern 22 is connected to one end of a sub-segment 211 of another first auxiliary pattern 21. This arrangement can further increase the density of auxiliary patterns near the corner 12 of the target pattern 10, which helps to further improve the light intensity distribution near the corner 12 of the target pattern 10, and is conducive to further reducing the rounding degree of the corner 12. It can further improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0098] It should be noted that in the embodiments of this application, the length of the first auxiliary graphic 21 is the sum of the lengths of two spaced sub-segments 211.

[0099] Optionally, such as Figure 1 and Figure 2 As shown, in one embodiment of this application, the mask further includes: at least two fifth auxiliary graphics 40, surrounded by second auxiliary combination graphics 30; and a fifth auxiliary graphic 40 is disposed on the outer side of at least one second auxiliary graphic 22 away from the corner 12 in the first auxiliary combination graphics 20.

[0100] This application is an example, such as Figure 1 and Figure 2 As shown, multiple fifth auxiliary graphics 40 are also provided within the space surrounded by the second auxiliary combined graphics 30, and the fifth auxiliary graphics 40 are located outside the space surrounded by the first auxiliary combined graphics 20.

[0101] In the embodiments of this application, such as Figure 1 and Figure 2 As shown, in the first auxiliary combination graphic 20, at least one second auxiliary graphic 22 is provided with a fifth auxiliary graphic 40 on the outer side away from the corner 12.

[0102] Optionally, such as Figure 1 and Figure 2 As shown, for the array formed by all the first auxiliary combination patterns 20, except for the second auxiliary pattern 22 located at the outermost corner of the first auxiliary combination pattern 20 located at the corner, a fifth auxiliary pattern 40 is provided on the outside of each second auxiliary pattern 22. This can increase the arrangement density of the auxiliary patterns near the corners 12 in the array, which helps to further improve the light intensity distribution near all corners 12 in the target pattern 10, and is conducive to further reducing the rounding degree of the corners 12. This can further improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0103] Optionally, such as Figure 1 and Figure 2 As shown, any two adjacent second auxiliary graphics 22 share a fifth auxiliary graphic 40 on their outer sides, which helps to simplify the design of the mask.

[0104] Optionally, such as Figure 1 and Figure 2 As shown, in one embodiment of this application, the center point between any two adjacent, spaced third auxiliary graphics 31 in the same second auxiliary combination graphics 30 is collinear with a central axis of the fifth auxiliary graphics 40.

[0105] In the embodiments of this application, such as Figure 1 As shown, a dashed line represents the line connecting the central axis of two adjacent, spaced-apart third auxiliary graphics 31 located on the innermost second auxiliary combination graphic 30, with the center point between the two adjacent, spaced-apart third auxiliary graphics 31 located within this dashed line; another dashed line represents the central axis of the fifth auxiliary graphic 40.

[0106] Optionally, such as Figure 1 As shown, the central axis of the fifth auxiliary graphic 40 is perpendicular to the line connecting the central axes of two adjacent spaced third auxiliary graphics 31, so that the fifth auxiliary graphic 40 is located inside the center point between any two adjacent spaced third auxiliary graphics 31, and the fifth auxiliary graphic 40 can fill the graphic gap between any two adjacent spaced third auxiliary graphics 31, and can further increase the arrangement density of auxiliary graphics around the target graphic 10.

[0107] In this embodiment of the application, in order to further illustrate the effect of the mask provided in the embodiment of the application, the applicant has... Figure 1 The graphic design scheme of the mask shown was simulated, and the simulation results are as follows: Figure 3a , Figure 3b , Figure 3c and Figure 3d As shown.

[0108] like Figure 3a for Figure 1 A comparison diagram of the target pattern 10 located at the center of the array, the simulated pattern 102 formed on the photoresist layer, the simulated pattern 101 formed by the related pattern design scheme, and the target pattern 10; Figure 3b for Figure 1 A comparison diagram of the target pattern 10 located at the edge of the array and between the two corners, a simulated pattern 103 formed on the photoresist layer, a simulated pattern 101 formed by a related pattern design scheme, and the target pattern 10; Figure 3c for Figure 1A comparison diagram of the target pattern 10 located at the corner of the array, the simulated pattern 104 formed on the photoresist layer, the simulated pattern 101 formed by the related pattern design scheme, and the target pattern 10.

[0109] like Figure 3a , Figure 3b and Figure 3c As shown, for any target pattern 10 located in the array, the graphic design scheme of the mask provided in this application embodiment significantly reduces the rounding degree of the corners 12 of the target pattern 10 compared with related graphic design schemes, which can improve the matching degree between the pattern formed by the photoresist layer after exposure and the target pattern 10.

[0110] like Figure 3d As shown, the horizontal axis represents the defocus distance D, and the vertical axis represents the error E. The units for both axes are nm (nanometers). Curve A represents the change in distance between the corner of the simulated pattern 104 formed on the photoresist layer of the target pattern 10 and the corner 12 of the target pattern 10 as a function of the focal distance D. Curve B represents the change in distance between the corner of the simulated pattern 101 formed on the photoresist layer of the pattern design scheme in the related art and the corner 12 of the target pattern 10 as a function of the focal distance D. Figure 3d As can be seen, for the same defocus distance D, compared with the graphic design schemes in related technologies, the simulated graphic formed on the photoresist layer of the target graphic 10 in the mask provided in this application embodiment has a smaller error with the target graphic 10, thereby significantly reducing the rounding degree of the corners 12 of the target graphic 10, which can improve the matching degree between the graphic formed on the photoresist layer after exposure and the target graphic 10.

[0111] In the embodiments of this application, when utilizing Figure 1 or Figure 2 In the process of manufacturing semiconductor devices using the mask shown, the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10 can be improved, which helps to ensure the area of ​​the hole pattern formed on the etched film layer, helps to reduce the resistance of the wires located in the hole, and thus helps to ensure the performance of the semiconductor device.

[0112] Based on the same inventive concept, this application provides a method for designing a photomask. This method is used to form a graphic design scheme for any of the photomasks in the above embodiments. A flowchart of the design method is shown below. Figure 4 As shown, steps S401 to S402 are included.

[0113] S401, determine whether the distance between any two adjacent target graphics 10 is less than a set threshold; if yes, proceed to step S402; otherwise, proceed to step S403.

[0114] S402, determine that each target graphic 10 is surrounded by at least one first auxiliary combined graphic 20, and all first auxiliary combined graphics 20 are surrounded by at least one second auxiliary combined graphic 30.

[0115] In this embodiment, the structure and arrangement of the first auxiliary combined graphic 20 and the second auxiliary combined graphic 30 are described in the above embodiments and will not be repeated here.

[0116] In the mask design method provided in this application embodiment, after determining that the distance between any two adjacent target patterns 10 is less than a set threshold, it is determined that each target pattern 10 is surrounded by at least one first auxiliary combination pattern 20, and all first auxiliary combination patterns 20 are surrounded by at least one second auxiliary combination pattern 30. This can increase the arrangement density of auxiliary patterns around each target pattern 10, which helps to increase the depth of field of the pattern in the mask and improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0117] Meanwhile, by setting each target pattern 10 to be surrounded by at least one first auxiliary combination pattern 20, each corner 12 of the target pattern 10 is provided with at least one second auxiliary pattern 22 that forms an acute or obtuse angle with the straight line containing the side 11. The distance between the second auxiliary pattern 22 and the adjacent corner 12 is less than the distance between the first auxiliary pattern 21 and the adjacent side 11. This can increase the arrangement density of auxiliary patterns near the corner 12, thereby helping to improve the light intensity distribution near the corner 12 of the target pattern 10 during the exposure process, which is beneficial to reducing the rounding degree of the corner 12 and improving the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0118] Optionally, in one embodiment of this application, step S402 further includes: determining that a fifth auxiliary graphic 40 is disposed on the outer side of the first auxiliary combined graphic 20 and the inner side of the second auxiliary combined graphic 30.

[0119] Optionally, for the array formed by all the first auxiliary combination patterns 20, a fifth auxiliary pattern 40 is provided outside the second auxiliary pattern 22 except for the outermost corner of the first auxiliary combination pattern 20 located in the corner.

[0120] In this embodiment, the structure and arrangement of the fifth auxiliary graphic 40 are described in the above embodiments and will not be repeated here.

[0121] Optionally, in one embodiment of this application, if step S401 determines that the distance between any two adjacent target graphics 10 is greater than a set threshold, then step S403 is executed: determining that each target graphic 10 is surrounded by at least two first auxiliary combined graphics 20.

[0122] Optionally, if it is determined that the distance between any two adjacent target graphics 10 is greater than a set threshold, then it is determined that each target graphic 10 is surrounded by three first auxiliary combined graphics 20, such as... Figure 5 As shown, in any two adjacent first auxiliary combination graphics 20, the length of the first auxiliary graphic 21 of the outer first auxiliary combination graphics 20 is greater than the length of the first auxiliary graphic 21 of the inner first auxiliary combination graphics 20; the length of the second auxiliary graphic 22 of the outer first auxiliary combination graphics 20 is greater than the length of the second auxiliary graphic 22 of the inner first auxiliary combination graphics 20.

[0123] like Figure 6 As shown, Figure 5 The diagram shows a comparison of a single target pattern 10 and multiple first auxiliary patterns 20 formed on a photoresist layer, a simulated pattern 105 formed by a related pattern design scheme, and the target pattern 10. For the single target pattern 10, using the mask pattern design scheme provided in this application embodiment, compared to related pattern design schemes, the rounding degree of the corners 12 of the target pattern 10 is significantly reduced, which can improve the matching degree between the pattern formed on the photoresist layer after exposure and the target pattern 10, thereby improving the matching degree between the pattern formed on the etched film layer and the target pattern 10.

[0124] Optionally, if it is determined that the distance between any two adjacent target graphics 10 is greater than a set threshold, then it is determined that each target graphic 10 is surrounded by three first auxiliary combined graphics 20, such as... Figure 7 As shown, in the same first auxiliary combination pattern 20, one end of each second auxiliary pattern 22 is connected to a sub-segment 211. Optionally, one end of the second auxiliary pattern 22 is connected to one end of a sub-segment 211 of a first auxiliary pattern 21, and the other end of the second auxiliary pattern 22 is connected to one end of a sub-segment 211 of another first auxiliary pattern 21. In any two adjacent first auxiliary combination patterns 20, the length of the sub-segment 211 of the outer first auxiliary combination pattern 20 is greater than the length of the sub-segment 211 of the inner first auxiliary combination pattern 20.

[0125] Optionally, in this embodiment of the application, after performing step S402 or step S403, the method further includes: performing optical proximity effect correction on the target pattern 10 to obtain the corrected target pattern 10.

[0126] By applying the embodiments of this application, at least the following beneficial effects can be achieved:

[0127] In the mask provided in this application embodiment, for a pattern array including at least two target patterns 10, since each target pattern 10 has at least one second auxiliary pattern 22 at its corner 12, which forms an acute or obtuse angle with the straight line containing the side 11, and the distance between the second auxiliary pattern 22 and the adjacent corner 12 is less than the distance between the first auxiliary pattern 21 and the adjacent side 11, the arrangement density of the auxiliary patterns near the corner 12 can be increased. Thus, during the exposure process, it helps to improve the light intensity distribution near the corner 12 of the target pattern 10, which is beneficial to reduce the rounding degree of the corner 12, and can improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0128] Meanwhile, by surrounding each target pattern 10 with at least one first auxiliary combined pattern 20 and setting a second auxiliary combined pattern 30 surrounding all the first auxiliary combined patterns 20, the arrangement density of the auxiliary patterns around each target pattern 10 can be increased, which helps to increase the depth of field of the pattern in the mask and can further improve the matching degree between the pattern formed on the etched film layer after exposure and the target pattern 10.

[0129] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0130] In the description of this application, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate directions or positional relationships based on the exemplary directions or positional relationships shown in the accompanying drawings. They are used to facilitate the description or simplification of the embodiments of this application and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0131] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0132] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0133] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0134] The above description is only a partial implementation of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application, without departing from the technical concept of this application, also fall within the protection scope of the embodiments of this application.

Claims

1. A photomask, characterized in that, include: At least two target graphics, wherein the target graphics include at least two corners and at least two sides; At least two first auxiliary combined graphics, each first auxiliary combined graphic surrounding a target graphic, the first auxiliary combined graphic including at least two first auxiliary graphics and at least two second auxiliary graphics; a first auxiliary graphic is disposed on the outer side of each side, the first auxiliary graphic being parallel to the adjacent side; a second auxiliary graphic is disposed on the outer side of each corner, the angle between the line containing the second auxiliary graphic and the line containing the side is an acute or obtuse angle; the distance between the second auxiliary graphic and the adjacent corner is less than the distance between the first auxiliary graphic and the adjacent side; At least one second auxiliary combination graphic surrounds all the first auxiliary combination graphics.

2. The photomask according to claim 1, characterized in that, The first auxiliary combined graphic is concentrically arranged with the target graphic surrounded by it; The first auxiliary combination graphic is a non-closed ring, and the first auxiliary graphic and the second auxiliary graphic are arranged alternately along the direction surrounding the target graphic; The length of the first auxiliary graphic is less than the length of the side.

3. The photomask according to claim 1, characterized in that, The second auxiliary combination graphic includes at least two third auxiliary graphics and at least two fourth auxiliary graphics; In the array formed by all the first auxiliary combined graphics, the third auxiliary graphic is disposed outside the outermost first auxiliary graphic, and the fourth auxiliary graphic is disposed outside the second auxiliary graphic located at the corner; the third auxiliary graphic is parallel to the adjacent first auxiliary graphic, and the fourth auxiliary graphic is parallel to the adjacent second auxiliary graphic.

4. The photomask according to claim 3, characterized in that, All of the second auxiliary combination graphics are non-closed rings; The second auxiliary combined pattern is concentrically arranged with the array surrounding it; in the same second auxiliary combined pattern, the fourth auxiliary pattern is spaced apart from the adjacent third auxiliary pattern, and any two adjacent fourth auxiliary patterns are spaced apart; the length of the third auxiliary pattern is greater than the length of the side.

5. The photomask according to claim 4, characterized in that, In the outermost second auxiliary combination pattern, a third auxiliary pattern is provided between any two adjacent fourth auxiliary patterns, and the length of the third auxiliary pattern is greater than the length of the third auxiliary pattern in the adjacent second auxiliary combination pattern.

6. The photomask according to claim 3, characterized in that, Except for the outermost second auxiliary combination pattern, the second auxiliary combination pattern is a non-closed ring; The second auxiliary combined pattern is concentrically arranged with the array surrounding it; in the same non-closed ring of the second auxiliary combined pattern, each end of the fourth auxiliary pattern is connected to a third auxiliary pattern, and any two adjacent third auxiliary patterns are spaced apart; the length of the third auxiliary pattern is greater than the length of the side.

7. The photomask according to claim 6, characterized in that, In the outermost second auxiliary combination pattern, all the third auxiliary patterns and the fourth auxiliary patterns are connected to form a closed loop.

8. The photomask according to claim 6 or 7, characterized in that, The first auxiliary graphic includes: two segments spaced apart; In the same first auxiliary combined graphic, one end of the second auxiliary graphic is connected to one end of a segment of one of the first auxiliary graphics, and the other end of the second auxiliary graphic is connected to one end of a segment of another first auxiliary graphic.

9. The photomask according to claim 1, characterized in that, Also includes: At least two fifth auxiliary graphics are surrounded by the second auxiliary combined graphics; In the first auxiliary combination graphic, at least one of the second auxiliary graphics is provided with a fifth auxiliary graphic on the outer side away from the corner.

10. The photomask according to claim 9, characterized in that, The center point between any two adjacent, spaced third auxiliary graphics in the same second auxiliary combination graphic is collinear with a central axis of the fifth auxiliary graphic.

11. A method for designing a photomask as described in any one of claims 1-10, characterized in that, include: Determine whether the distance between any two adjacent target graphics is less than a set threshold. If the value is less than the set threshold, then each of the target graphics is determined to be surrounded by at least one of the first auxiliary combined graphics, and all the first auxiliary combined graphics are surrounded by at least one of the second auxiliary combined graphics.

12. The mask design method according to claim 11, characterized in that, If the value is less than the set threshold, then it is determined that each of the target graphics is surrounded by at least one of the first auxiliary combined graphics, and all the first auxiliary combined graphics are surrounded by at least one of the second auxiliary combined graphics, further comprising: A fifth auxiliary graphic is determined to be set on the outside of the first auxiliary combined graphic and on the inside of the second auxiliary combined graphic.

13. The mask design method according to claim 11, characterized in that, After determining whether the distance between any two adjacent target graphics is less than a set threshold, the following steps are also included: If the value is greater than the set threshold, then each target graphic is determined to be surrounded by at least two first auxiliary combined graphics.

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