Method and device for correcting optical proximity effect of mask pattern

Abstract

The invention provides a mask pattern optical proximity effect correction method and device. The mask pattern optical proximity effect correction method comprises the steps of obtaining a target pattern, a mask pattern correction rule and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established according to a plurality of test patterns and first exposure patterns of the test patterns, and the test patterns are obtained by changing the size of the target pattern. Correcting the target graph according to the mask graph correction rule to obtain a first corrected graph, continuously correcting the first corrected graph according to the mask graph correction model to obtain a second corrected graph, and exposing the second corrected graph to obtain a second exposed graph, the total difference value between the second exposure pattern and the target pattern is smaller than or equal to a difference threshold value. The target graph is initially corrected by using the mask graph correction rule, so that the difficulty of subsequently correcting the target graph by using the mask graph correction model is reduced, the correction time is shortened, the correction speed is improved, and the correction efficiency is further improved.

Description

Technical Field

[0001] The present invention relates to the field of computers, and in particular to a method and device for optical proximity correction of mask patterns. Background Art

[0002] With the development of semiconductor-related technologies, one of the important technologies in the manufacture of semiconductor devices, lithography technology, is also developing rapidly. Traditional optical lithography technologies include Deep Ultraviolet Lithography (DUVL) and Extreme Ultraviolet Lithography (EUVL).

[0003] Reference Figure 1 As shown, it is an exposure schematic diagram of an extreme ultraviolet lithography technology. It can be seen from the figure that traditional optical lithography technology relies on a light source to irradiate a mask (with a pattern to be transferred on the mask), and through a projection system, projects the pattern onto a photoresist. Then, the photoresist undergoes a photochemical reaction, and after steps such as baking and developing and cleaning, a lithography image is formed.

[0004] Due to the existence of diffraction effects, when the line width of the lithography image is less than the wavelength of the light source, it is necessary to perform optical proximity correction (OPC) processing on the pattern on the mask in order to achieve the initial exposure purpose of the lithography image.

[0005] However, the current optical proximity correction time for mask patterns is relatively long, and the correction efficiency is low. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a method and device for optical proximity correction of mask patterns, which can shorten the optical proximity correction time and improve the correction efficiency.

[0007] To achieve the above purpose, this application has the following technical solutions:

[0008] This application provides a method for optical proximity correction of mask patterns, including:

[0009] Obtain a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established based on a plurality of test patterns and the first exposure pattern of the test patterns, and the test patterns are obtained by changing the size of the target pattern;

[0010] Correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern;

[0011] Continuously correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern;

[0012] Expose the second corrected pattern to obtain a second exposed pattern, and the total difference value between the second exposed pattern and the target pattern is less than the difference threshold.

[0013] Optionally, the method further includes:

[0014] Cut the edges of the target pattern, and the edges of the target pattern are cut into multiple small edges;

[0015] The step of correcting the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and continuously correcting the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern includes:

[0016] Adjust the positions of the multiple small edges of the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and the first corrected pattern includes the multiple small edges;

[0017] Continuously move the positions of the multiple small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern.

[0018] Optionally, the step of continuously moving the positions of the multiple small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern includes:

[0019] Move the positions of the multiple small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a moved pattern after each movement;

[0020] Simulate the exposure of the moved pattern to obtain a third exposed pattern;

[0021] Calculate the total difference value between the third exposed pattern after each movement and the target pattern, and determine the moved pattern corresponding to the third exposed pattern with the smallest total difference value as the second corrected pattern.

[0022] Optionally, the target pattern includes multiple first small edges, and the third exposed pattern includes multiple second small edges;

[0023] The step of calculating the total difference value between the third exposed pattern after each movement and the target pattern includes:

[0024] Calculate the edge placement error between each second small edge included in the third exposed pattern and the first small edge corresponding to the second small edge included in the target pattern;

[0025] Calculate the total difference value between the third exposure pattern and the target pattern after each movement based on multiple edge placement errors.

[0026] Optionally, the calculating the total difference value between the third exposure pattern and the target pattern after each movement based on multiple edge placement errors includes:

[0027] The total difference value is the sum of the squares of multiple edge placement errors, and the edge placement error is the straight-line distance between the second smallest side and the corresponding first smallest side.

[0028] Optionally, the mask pattern correction rule includes the line width correction rule and the line end correction rule of the target pattern.

[0029] Optionally, the method further includes:

[0030] Design the sizes of multiple test patterns according to the size of the target pattern;

[0031] Set exposure conditions, and actually expose multiple test patterns respectively using the exposure conditions to obtain the first exposure pattern of each test pattern;

[0032] Establish the mask pattern correction rule and the mask pattern correction model according to the size of the test pattern and the size of the first exposure pattern.

[0033] The present application provides a mask pattern optical proximity effect correction device, including:

[0034] An acquisition unit for acquiring a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established based on multiple test patterns and the first exposure pattern of the test patterns, and the test patterns are obtained by changing the size of the target pattern;

[0035] A first correction unit for correcting the target pattern according to the mask pattern correction rule to obtain a first corrected pattern;

[0036] A second correction unit for further correcting the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern;

[0037] An exposure unit for exposing the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than a difference threshold.

[0038] Optionally, the device further includes:

[0039] A cutting unit for cutting the edges of the target pattern, and the edges of the target pattern are cut into multiple small edges;

[0040] The first correction unit is configured to:

[0041] Adjust the positions of the multiple small edges of the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and the first corrected pattern includes the multiple small edges;

[0042] The second correction unit is configured to:

[0043] Continuously move the positions of the multiple small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern.

[0044] Optionally, the apparatus further includes a testing unit, and the testing unit is configured to:

[0045] Design the sizes of multiple test patterns according to the size of the target pattern;

[0046] Set exposure conditions, and respectively perform actual exposure on the multiple test patterns using the exposure conditions to obtain a first exposure pattern of each test pattern;

[0047] Establish the mask pattern correction rule and the mask pattern correction model according to the size of the test pattern and the size of the first exposure pattern.

[0048] This application provides a method for correcting the optical proximity effect of a mask pattern, including: obtaining a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established according to multiple test patterns and the first exposure patterns of the test patterns, and the test patterns are obtained by changing the size of the target pattern, that is, by using multiple test patterns to construct the mask pattern correction rule and the mask pattern correction model for correcting the optical proximity effect of the target pattern. Correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and continue to correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern, that is, by first using the mask pattern correction rule to correct the target pattern, the initial correction of the target pattern can be realized, and the difficulty of correcting the target pattern using the mask pattern correction model subsequently can be reduced. Thus, by combining the two correction methods, the correction time can be greatly reduced. Expose the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than or equal to the difference threshold. It can be seen that combining the two correction methods can reduce the correction time, improve the correction speed, and thus improve the correction efficiency. Description of the Drawings

[0049] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0050] Figure 1 Shows an exposure schematic diagram of an extreme ultraviolet lithography technology;

[0051] Figure 2 Shows a schematic diagram of a mask pattern and a lithographic image;

[0052] Figure 3 Shows a schematic flowchart of a mask pattern optical proximity effect correction method provided by an embodiment of the present application;

[0053] Figure 4 Shows a schematic diagram of a target pattern provided by an embodiment of the present application;

[0054] Figure 5 Shows a schematic diagram of a target pattern correction provided by an embodiment of the present application;

[0055] Figure 6 Shows a schematic diagram of a mask pattern correction rule provided by an embodiment of the present application;

[0056] Figure 7 Shows a schematic diagram of an edge cutting of a target pattern provided by an embodiment of the present application;

[0057] Figure 8 Shows another schematic diagram of a target pattern correction provided by an embodiment of the present application;

[0058] Figure 9 Shows a schematic structural diagram of a mask pattern optical proximity effect correction device provided by an embodiment of the present application. Detailed implementation manners

[0059] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will give a detailed description of the specific implementation manners of the present application with reference to the accompanying drawings.

[0060] In the following description, many specific details are set forth to fully understand the present application. However, the present application can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0061] This application will be described in detail with reference to the schematic diagrams. When describing the embodiments of this application, for ease of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of this application herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0062] With the development of semiconductor-related technologies, one of the important technologies in the manufacturing of semiconductor devices, lithography technology, is also developing rapidly. Traditional optical lithography technologies include Deep Ultraviolet Lithography (DUVL) and Extreme Ultraviolet Lithography (EUVL).

[0063] Reference Figure 1 As shown, it is an exposure schematic diagram of an extreme ultraviolet lithography technology. It can be seen from the figure that traditional optical lithography technology relies on a light source irradiating a mask (with the pattern to be transferred on the mask), passing through a projection system, projecting the pattern onto the photoresist, then the photoresist undergoes a photochemical reaction, and then through steps such as baking and developing and cleaning, etc., to form a lithography image.

[0064] Due to the existence of the diffraction effect, when the line width of the lithography image is less than the wavelength of the light source, as shown in Reference Figure 2 As shown, there are significant differences between the pattern on the mask ( Figure 2 left side) and the lithography image ( Figure 2 right side). At this time, the pattern on the mask must be processed by Optical Proximity Correction (OPC) in order to achieve the initial purpose of exposure for the lithography image, that is, to make the lithography image consistent with the initial pattern on the mask.

[0065] At the 0.18-micron (180-nanometer) and below nodes, that is, when the line width of the pattern is less than 180 nanometers, OPC needs to be used to correct the pattern on the mask in order to make the lithography image more consistent with the initial pattern on the mask and achieve better pattern fidelity. OPC can generally be divided into Rule-Based Mask Pattern Correction (RBOPC) and Model-Based Mask Pattern Correction (MBOPC). At the 180-nanometer (nm) node (usually up to the 130-nm node at most), generally choosing RBOPC can meet the correction effect. In advanced nodes, MBOPC is usually used. The advantage of RBOPC is its fast speed and relative simplicity. The disadvantage is that the correction effect for relatively complex patterns greatly depends on the ability and experience of the staff, and it is also difficult to correct the details of complex patterns. The advantage of MBOPC is its convenience and good correction for any pattern. The disadvantage is that it highly depends on the accuracy of the model and the speed decreases significantly as the pattern increases.

[0066] As the nodes become more advanced and the pattern sizes become smaller, with the same mask area, the number of patterns increases. The time consumed by MBOPC is huge. For example, when performing MBOPC on a certain mask of the 180nm node, it took about 8 hours to run on a 32-core server.

[0067] That is to say, the current optical proximity effect correction time for mask patterns is long and the correction efficiency is low.

[0068] Based on this, the present application provides a method for correcting the optical proximity effect of mask patterns, including: obtaining a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established according to a plurality of test patterns and the first exposure pattern of the test patterns. The test patterns are obtained by changing the size of the target pattern, that is, by using a plurality of test patterns to construct a mask pattern correction rule and a mask pattern correction model for correcting the optical proximity effect of the target pattern. Correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and continue to correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern. That is, by first correcting the target pattern using the mask pattern correction rule, the initial correction of the target pattern can be realized, reducing the difficulty of subsequent correction of the target pattern using the mask pattern correction model. Thus, by combining the two correction methods, the correction time can be greatly reduced. Expose the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than or equal to the difference threshold. It can be seen that combining the two correction methods can reduce the correction time, improve the correction speed, and thus improve the correction efficiency.

[0069] To better understand the technical solution and technical effect of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0070] Refer to Figure 3 As shown, it is a schematic flowchart of a method for correcting the optical proximity effect of mask patterns provided by an embodiment of the present application. The method includes the following steps:

[0071] S101, obtain a target pattern, a mask pattern correction rule, and a mask pattern correction model.

[0072] In the embodiment of the present application, the target pattern is a pattern on the mask, which is a pattern that wants to use lithography to copy the structure of the target pattern onto the photoresist. However, in fact, due to the diffraction effect, there is a large difference between the pattern on the mask and the lithography image. At this time, the optical proximity effect can be used to correct the target pattern, that is, to correct the pattern on the mask so that the lithography pattern is closer to the target pattern before correction.

[0073] Optical proximity effect correction methods include rule-based mask pattern correction (RBOPC) and model-based mask pattern correction (MBOPC). Among them, rule-based mask pattern correction uses mask pattern correction rules to correct the target pattern to obtain a corrected pattern, and model-based mask pattern correction uses a mask pattern correction model to correct the target pattern to obtain a corrected pattern.

[0074] Specifically, the mask pattern correction rules include the line width correction rule of the target pattern, the end correction rule of the target pattern, and the height correction rule of the target pattern.

[0075] In practical applications, the target pattern is usually a dense line pattern. Refer to Figure 4 As shown, the line width is also called the critical dimension (CD), the distance between lines can be expressed as SPACE, the height of the line can be expressed as HEIGHT, and the pitch of the dense line pattern is the sum of SPACE and CD. Figure 4 In , CD = 245 nm and SPACE = 265 nm.

[0076] The correction of the target pattern can be achieved by adjusting the line width, height, and the distance between lines of the target pattern. These adjusted line width, height, and the distance between lines can all be used as mask pattern correction rules.

[0077] As a possible implementation, usually the mask pattern correction rule is a one-dimensional correction rule for the target pattern, that is, by adjusting the position of the edge of the target pattern to adjust the line width, height, and the distance between lines of the target pattern, and further adjust the lithography image. The data for adjusting the target pattern in the mask pattern correction rule is determined according to the line width, height, and the distance between lines of the target pattern.

[0078] As an example, when the line width is greater than 240 nm and less than 250 nm, and SPACE is greater than or equal to 260 nm and less than 270 nm, the correction of the target pattern can be an increase in the line width by 4 nm. For example, it can be that the position of the right side of the line included in the target pattern is moved 4 nm to the right. Refer to Figure 5 As shown.

[0079] It should be noted that the correspondence between the data for target pattern adjustment and the line width, height, and distance between lines of the target pattern is established based on multiple test patterns and the first exposure patterns of the test patterns. That is to say, the mask pattern correction rules are established according to multiple test patterns and the first exposure patterns of the test patterns. Among them, the test patterns are obtained by changing the dimensions of the target pattern. That is, multiple test patterns obtained by changing the dimensions of the target pattern are used for exposure testing to obtain multiple first exposure patterns, and the mask pattern correction rules are constructed based on the dimensions of the first exposure patterns, the dimensions of the test patterns, and the dimensions of the target pattern.

[0080] Specifically, the dimensions of multiple test patterns can be designed respectively according to the dimensions of the target pattern.

[0081] For example, when the target pattern is a dense line pattern with CD = 160 nm and SPACE = 160 nm, the dimensions of the test patterns can be CD = 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, or 170 nm, and SPACE = 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, or 170 nm respectively. That is, the dimensions of multiple test patterns include the dimensions of the target pattern.

[0082] Set the exposure conditions, and actually expose multiple test patterns respectively under the same exposure conditions. That is, expose multiple test patterns using a lithography machine to obtain the first exposure pattern of each test pattern. To ensure data consistency, the exposure conditions for multiple test patterns are the same. The exposure conditions can include light source conditions, exposure time, and number of exposures, etc. The light source conditions can include the light source wavelength.

[0083] In practical applications, when exposing the test patterns, first set the test patterns on the mask, and then actually expose the mask.

[0084] After exposing multiple test patterns, multiple first exposure patterns are obtained respectively, and the dimensions of multiple first exposure patterns are collected. To improve data accuracy, the dimensions of the first exposure patterns can be collected multiple times, and then the average value is taken. During the process of taking the average value, the 3-sigma rule of the normal distribution is usually satisfied.

[0085] After collecting the dimensions of multiple first exposure patterns, the mask pattern correction rules can be established according to the dimensions of the test patterns and the dimensions of the first exposure patterns.

[0086] As an example, refer to Figure 6 As shown, it is an example of a mask pattern correction rule. Where the unit is nanometre. Figure 6Positive and negative values represent the moving directions of the edges of the lines included in the target pattern. A negative value indicates movement to the right, and a positive value indicates movement to the left. As can be seen from Figure 6 when the line width of the target pattern is greater than or equal to 200 nm and less than 210 nm, and SPACE is greater than or equal to 260 nm and less than 270 nm, the correction to the target pattern can be to increase the line width by 1 nm. For example, the position of the right edge of the line included in the target pattern can be moved 1 nm to the right.

[0087] In the embodiments of the present application, the model-based mask pattern correction is to simulate the exposure pattern by establishing a reliable mask pattern correction model, and then correct the target pattern. Specifically, it can be to move the positions of the respective edges of the target pattern to observe the total difference value between the exposure pattern and the target pattern. When the total difference value is less than the difference threshold, that is, when the total difference value reaches the expectation, the movement ends, and the moved target pattern is the corrected pattern. That is to say, it is necessary to perform multiple rounds of correction on the target pattern using the mask pattern correction model to finally achieve the correction goal, that is, to make the exposure pattern close to the target pattern before correction.

[0088] Similar to the establishment of the mask pattern correction rules, the mask pattern correction model is also established based on multiple test patterns and the first exposure patterns of the test patterns. The specific process of obtaining the data for establishing the mask pattern correction model is the same as the process of obtaining the data for establishing the mask pattern correction rules, and will not be elaborated here. That is to say, not only can the mask pattern correction rules be established based on the sizes of the test patterns and the first exposure patterns, but also the mask pattern correction model can be established simultaneously.

[0089] It should be noted that to improve the fineness when using the mask pattern correction model to correct the target pattern, and thus improve the similarity between the exposure pattern and the target pattern, the edges of the target pattern can be cut, that is, the edges of the target pattern are cut into multiple small edges, as shown in Figure 7 As shown. Figure 7 For the rectangle shown in, the edges of the rectangle can be divided. For example, the longer side of the rectangle can be divided into 2 parts, that is, the 4 edges of the rectangle are divided into 6 separate small edges, numbered 1 - 6 respectively, and each small edge can be moved independently. Figure 7 It shows that the position of the small edge numbered 6 can be moved 5 nm to the right.

[0090] In an embodiment of the present application, the exposure pattern of the target pattern, that is, the lithography image in the photoresist, can be simulated and calculated by using a mask pattern correction model, and the total difference value between the exposure pattern and the target pattern is calculated. Then, each small edge of the segmentation is moved to correct the target pattern to obtain a corrected pattern. The total difference value between the exposure pattern corresponding to the corrected pattern and the target pattern is calculated again. After the positions of the small edges are moved multiple times, when the total difference value meets a preset condition, for example, when the total difference value is the smallest, the corrected pattern corresponding to when the preset condition is met can be determined as the output result of the mask pattern correction model.

[0091] As an example, referring to Figure 8 as shown, the target pattern is a rectangle, the edges of the target pattern are cut into 6 small edges, and the ellipse is the exposure pattern of the target pattern. To make the exposure pattern close to the target pattern, the target pattern is corrected. The small edge numbered 1 can be moved upward by a certain distance, and the small edges numbered 5 and 6 can be moved to the right by a certain distance to obtain a corrected pattern. The corrected pattern is exposed to obtain the exposure pattern of the corrected pattern. From Figure 8 it can be seen that the exposure pattern after correcting the target pattern by using the mask pattern correction model is closer to the shape of the target pattern ( Figure 8 the shape formed by the dotted lines of the right rectangle).

[0092] In practical applications, when using the mask pattern correction model to correct the target pattern, it is necessary to move the positions of the small edges through multiple rounds to achieve the best correction effect. The best correction effect is that the total difference value meets a preset condition, for example, the total difference value is the smallest. For each round of position movement, the movement amount of each small edge is calculated by using a relevant algorithm, and the total difference value after this round of movement is calculated. After multiple rounds, the movement amount of each small edge when the best correction effect is achieved can be gradually determined. Among them, the relevant algorithm can be an algorithm for the optimal solution of multiple parameters, such as the quasi-Newton method, etc.

[0093] As an example, it takes 20 hours in total to correct the target pattern by using the mask pattern correction model, and the number of optimization rounds is 10. It can be roughly considered that each round of optimization takes 2 hours.

[0094] S102. Correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern.

[0095] In the embodiments of the present application, the correction of the target pattern can be achieved by separately using the mask pattern correction rule and the mask pattern correction model. However, the target pattern of the mask pattern correction rule is relatively simple, and the mask pattern correction model takes a long time to correct due to the need to adjust the position of small edges in multiple rounds. Therefore, the two can be combined. First, the mask pattern correction rule is used to perform the first correction on the target pattern, thereby reducing the difficulty of subsequent correction of the target pattern using the mask pattern correction model. That is, by using the mask pattern correction rule to initially move the edges of the target pattern, the movement direction and position of each edge are roughly determined. Subsequently, only the mask pattern correction model needs to continue to perform fine correction on this basis, which can reduce the number of small edge adjustment rounds of the mask pattern correction model and thus reduce the overall correction time.

[0096] That is to say, the core of optical proximity effect correction lies in the movement amount of the edges of the target pattern when correcting the target pattern. As Figure 8 shown, the optimal movement amount of the small edge numbered 1 may be 15 nm. However, when using the mask pattern correction model to move the small edge numbered 1 of the target pattern in multiple rounds, the movement amount in each round may be 9 nm in the first round, 4 nm in the second round, 5 nm in the third round, -4 nm in the fourth round, 1 nm in the fifth round, and then no movement or oscillation in subsequent rounds. Finally, the best correction effect is obtained in the 10th round.

[0097] Assume that the target pattern is corrected by using the mask pattern correction rule, and the small edge numbered 1 is directly moved by 15 nm, then the correction of the small edge numbered 1 is completed in the first round. Assume that the target pattern is corrected by using the mask pattern correction rule, the small edge numbered 1 is moved by 12 nm, and an initial movement amount is given to other small edges, then it does not require 10 rounds to achieve the best correction effect that previously required 10 rounds of movement. Therefore, the initial correction of the target pattern can be performed by using the mask pattern correction rule to provide an initial movement amount for each edge of the target pattern, reduce the number of rounds of subsequent correction by the mask pattern correction model, improve the correction efficiency, and reduce the correction time consumption.

[0098] Specifically, the mask pattern correction rule constructed according to the test pattern and the first exposure pattern can be used to perform the first correction on the target pattern to obtain the first corrected pattern.

[0099] As a possible implementation manner, when the edge of the target pattern is cut into multiple small edges, the positions of the multiple small edges of the target pattern can be adjusted according to the mask pattern correction rule to obtain the first corrected pattern. At this time, the first corrected pattern also includes multiple small edges.

[0100] S103, continue to correct the first corrected pattern according to the mask pattern correction model to obtain the second corrected pattern.

[0101] In an embodiment of the present application, the target pattern is initially corrected by using the mask pattern correction rule to obtain a first corrected pattern. Based on the result of the initial correction, the first corrected pattern is continuously corrected by using the mask pattern correction model to obtain a second corrected pattern.

[0102] Specifically, since the first corrected pattern also includes multiple small edges, multiple rounds of movement can be continued on the positions of the multiple small edges of the first corrected pattern according to the mask pattern correction model, so as to obtain the second corrected pattern.

[0103] When multiple rounds of movement are performed on the positions of the multiple small edges of the first corrected pattern by using the mask pattern correction model, a moved pattern after each movement can be obtained, the moved pattern is simulated and exposed to obtain a third exposed pattern, the total difference value between the third exposed pattern and the target pattern after each movement is calculated, and the moved pattern corresponding to the third exposed pattern with the smallest total difference value is determined as the second corrected pattern. That is to say, the smallest total difference value is the best correction effect. In this way, by calculating the total difference value between the third exposed pattern and the target pattern after each movement, the best correction effect of the mask pattern correction model can be determined.

[0104] As a possible implementation manner, the total difference value can be calculated according to the edge placement error of each small edge among the multiple small edges, that is, the total difference value is calculated according to multiple edge placement errors. The total difference value can be the sum of the squares of multiple edge placement errors, and can be expressed by the formula:

[0105] cost = ∑epe 2 , where epe is the edge placement error and cost is the total difference value.

[0106] As an example, the edge placement error refers to the straight-line distance between the target pattern and the small edge corresponding to the third exposed pattern. The target pattern includes multiple first small edges, and the third exposed pattern includes multiple second small edges. The edge placement error between each second small edge included in the third exposed pattern and the first small edge corresponding to the second small edge included in the target pattern can be calculated.

[0107] As another example, the midpoint of each small edge is defined as an evaluation point, and the distance between each edge of the third exposed pattern and the evaluation point corresponding to the edge is calculated respectively, then the edge placement error can be obtained.

[0108] S104, expose the second corrected pattern to obtain a second exposed pattern.

[0109] In an embodiment of the present application, after obtaining the best correction effect by performing multiple rounds of correction on the first corrected pattern using the mask pattern correction model, a second corrected pattern with a size change of the target pattern is obtained. Continuing the actual exposure on the second corrected pattern to obtain a second exposure pattern, the total difference value between the second exposure pattern and the target pattern is less than or equal to the difference threshold, that is, the difference between the second exposure pattern and the target pattern is small, which can meet the lithography requirements. The difference threshold can be determined according to the total difference value between the third exposure pattern and the target pattern. For example, the difference threshold can be set as the minimum value of the total difference values between multiple third exposure patterns and the target pattern.

[0110] It can be seen that the present application provides a method for optical proximity effect correction of mask patterns, including: obtaining a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established based on multiple test patterns and the first exposure patterns of the test patterns. The test patterns are obtained by changing the size of the target pattern, that is, by using multiple test patterns to construct a mask pattern correction rule and a mask pattern correction model for optical proximity effect correction of the target pattern. Correcting the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and continuing to correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern. That is, by first correcting the target pattern using the mask pattern correction rule, the initial correction of the target pattern can be realized, reducing the difficulty of subsequent correction of the target pattern using the mask pattern correction model. Thus, by combining the two correction methods, the correction time can be greatly reduced. Exposing the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than or equal to the difference threshold. It can be seen that combining the two correction methods can reduce the correction time, improve the correction speed, and thus improve the correction efficiency.

[0111] Based on the method for optical proximity effect correction of mask patterns provided in the above embodiments, the present application embodiment also provides a device for optical proximity effect correction of mask patterns. Refer to Figure 9 As shown, it is a schematic structural diagram of a device for optical proximity effect correction of mask patterns provided by an embodiment of the present application. The device 200 for optical proximity effect correction of mask patterns provided by the embodiment of the present application includes:

[0112] An obtaining unit 210, configured to obtain a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established based on multiple test patterns and the first exposure patterns of the test patterns, and the test patterns are obtained by changing the size of the target pattern;

[0113] The first correction unit 220 is configured to correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern;

[0114] The second correction unit 230 is configured to continuously correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern;

[0115] The exposure unit 240 is configured to expose the second corrected pattern to obtain a second exposed pattern, and a total difference value between the second exposed pattern and the target pattern is less than or equal to a difference threshold.

[0116] Optionally, the apparatus further includes:

[0117] A cutting unit is configured to cut the edges of the target pattern, and the edges of the target pattern are cut into a plurality of small edges;

[0118] The first correction unit 220 is configured to:

[0119] Adjust the positions of the plurality of small edges of the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and the first corrected pattern includes the plurality of small edges;

[0120] The second correction unit 230 is configured to:

[0121] Continuously move the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern.

[0122] Optionally, the second correction unit 230 is configured to:

[0123] Move the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a moved pattern after each movement;

[0124] Perform simulated exposure on the moved pattern to obtain a third exposed pattern;

[0125] Calculate a total difference value between the third exposed pattern after each movement and the target pattern, and determine the moved pattern corresponding to the third exposed pattern with the smallest total difference value as the second corrected pattern.

[0126] Optionally, the target pattern includes a plurality of first small edges, and the third exposed pattern includes a plurality of second small edges;

[0127] The second correction unit 230 is configured to:

[0128] Calculate an edge placement error between each of the second small edges included in the third exposed pattern and a first small edge corresponding to the second small edge included in the target pattern;

[0129] Calculate the total difference value between the third exposure pattern and the target pattern after each movement based on multiple edge placement errors.

[0130] Optionally, the second correction unit 230 is configured to:

[0131] The total difference value is the sum of the squares of multiple edge placement errors, and the edge placement error is the straight-line distance between the second shortest side and the first shortest side corresponding to the second shortest side.

[0132] Optionally, the mask pattern correction rule includes the line width correction rule and the line end correction rule of the target pattern.

[0133] Optionally, the device further includes a test unit configured to:

[0134] Design the sizes of multiple test patterns according to the size of the target pattern;

[0135] Set exposure conditions, and actually expose multiple test patterns respectively using the exposure conditions to obtain the first exposure pattern of each test pattern;

[0136] Establish the mask pattern correction rule and the mask pattern correction model according to the size of the test pattern and the size of the first exposure pattern.

[0137] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment.

[0138] The above are only the preferred embodiments of the present application. Although the present application has been disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the protection of the technical solution of the present application.

Claims

1. A method for optical proximity effect correction of a mask pattern, characterized in that, it includes: Obtaining a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established based on a plurality of test patterns and the first exposure pattern of the test patterns, and the test patterns are obtained by changing the size of the target pattern; Correcting the target pattern according to the mask pattern correction rule to obtain a first corrected pattern; Continuing to correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern; Exposing the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than or equal to a difference threshold.

2. The method according to claim 1, characterized in that, the method further includes: Cutting the edges of the target pattern, and the edges of the target pattern are cut into a plurality of small edges; The correcting the target pattern according to the mask pattern correction rule to obtain a first corrected pattern and continuing to correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern includes: Adjusting the positions of the plurality of small edges of the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and the first corrected pattern includes the plurality of small edges; Continuing to move the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern.

3. The method according to claim 2, characterized in that, The continuing to move the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern includes: Moving the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a moved pattern after each move; Performing simulation exposure on the moved pattern to obtain a third exposure pattern; Calculating the total difference value between the third exposure pattern after each move and the target pattern, and determining the moved pattern corresponding to the third exposure pattern with the smallest total difference value as the second corrected pattern.

4. The method according to claim 3, characterized in that, the target pattern includes a plurality of first small edges, and the third exposure pattern includes a plurality of second small edges; The calculating the total difference value between the third exposure pattern after each move and the target pattern includes: Calculating the edge placement error between each second small edge included in the third exposure pattern and the first small edge corresponding to the second small edge included in the target pattern; Calculating the total difference value between the third exposure pattern after each move and the target pattern based on the plurality of edge placement errors.

5. The method according to claim 1, characterized in that, The calculating the total difference value between the third exposure pattern after each move and the target pattern based on the plurality of edge placement errors includes: The total difference value is the sum of the squares of a plurality of the edge placement errors, and the edge placement error is the straight-line distance between the second shortest side and the first shortest side corresponding to the second shortest side.

6. The method according to any one of claims 1-5, wherein, the mask pattern correction rule includes a line width correction rule of the target pattern and a line end correction rule of the target pattern.

7. The method according to any one of claims 1-5, wherein, the method further includes: designing the sizes of a plurality of the test patterns respectively according to the size of the target pattern; setting exposure conditions, and respectively performing actual exposure on the plurality of test patterns by using the exposure conditions to obtain a first exposure pattern of each test pattern; establishing the mask pattern correction rule and the mask pattern correction model according to the sizes of the test patterns and the sizes of the first exposure patterns.

8. A mask pattern optical proximity effect correction device, wherein, it includes: an acquisition unit, configured to acquire a target pattern, a mask pattern correction rule, and a mask pattern correction model; the mask pattern correction rule and the mask pattern correction model are established according to a plurality of test patterns and the first exposure patterns of the test patterns, and the test patterns are obtained by changing the size of the target pattern; a first correction unit, configured to correct the target pattern according to the mask pattern correction rule to obtain a first corrected pattern; a second correction unit, configured to continuously correct the first corrected pattern according to the mask pattern correction model to obtain a second corrected pattern; an exposure unit, configured to perform exposure on the second corrected pattern to obtain a second exposure pattern, and the total difference value between the second exposure pattern and the target pattern is less than or equal to a difference threshold.

9. The device according to claim 8, wherein, the device further includes: a cutting unit, configured to cut the edges of the target pattern, and the edges of the target pattern are cut into a plurality of small edges; the first correction unit is configured to: adjust the positions of the plurality of small edges of the target pattern according to the mask pattern correction rule to obtain a first corrected pattern, and the first corrected pattern includes the plurality of small edges; the second correction unit is configured to: continuously move the positions of the plurality of small edges of the first corrected pattern in multiple rounds according to the mask pattern correction model to obtain a second corrected pattern.

10. The device according to any one of claims 8-9, wherein, the device further includes a test unit, and the test unit is configured to: design the sizes of a plurality of the test patterns respectively according to the size of the target pattern; set exposure conditions, and respectively perform actual exposure on the plurality of test patterns by using the exposure conditions to obtain a first exposure pattern of each test pattern; establish the mask pattern correction rule and the mask pattern correction model according to the sizes of the test patterns and the sizes of the first exposure patterns.

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