WO2021203966A1 - 光学临近效应修正方法及装置 - Google Patents

光学临近效应修正方法及装置 Download PDF

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Publication number
WO2021203966A1
WO2021203966A1 PCT/CN2021/082461 CN2021082461W WO2021203966A1 WO 2021203966 A1 WO2021203966 A1 WO 2021203966A1 CN 2021082461 W CN2021082461 W CN 2021082461W WO 2021203966 A1 WO2021203966 A1 WO 2021203966A1
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Prior art keywords
pattern
original target
proximity effect
optical proximity
graphic
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PCT/CN2021/082461
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English (en)
French (fr)
Inventor
陈志立
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长鑫存储技术有限公司
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Priority to US17/461,547 priority Critical patent/US20210389663A1/en
Publication of WO2021203966A1 publication Critical patent/WO2021203966A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/30—Circuit design
    • G06F30/39—Circuit design at the physical level
    • G06F30/398—Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM]
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/36—Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes

Definitions

  • the present disclosure relates to the field of semiconductor technology, and in particular to a method and device for correcting optical proximity effect.
  • the optical proximity effect may make the right-angle corners be rounded, and the line width of the photolithographic pattern may increase or decrease.
  • OPE optical proximity correction
  • the embodiments of the present disclosure provide a method and device for correcting the optical proximity effect to solve the problem of serious distortion of the lithography pattern after the existing optical proximity effect is corrected.
  • embodiments of the present disclosure provide a method for correcting optical proximity effect, including:
  • embodiments of the present disclosure also provide an optical proximity effect correction device, which is used to implement the optical proximity effect correction method provided by any embodiment of the present disclosure, including:
  • the secondary processing module is used to obtain the original target graphic, and preprocess the original target graphic to form a secondary target graphic, so that the secondary target graphic meets the preset process rules;
  • a correction module configured to perform optical proximity effect correction processing on the secondary target graphic to obtain a correction graphic
  • the contour module is used to obtain the simulated contour of the original target graphic according to the corrected graphic
  • a deviation calculation module which calculates the deviation between the simulated contour and the original target graphic
  • the iterative module is used to cyclically call the correction module and the contour module until the deviation value obtained by the deviation calculation module meets the process requirement.
  • the original target pattern is preprocessed, and the original target pattern that will affect the accuracy of the exposure pattern finally exposed on the film layer is pre-corrected and adjusted to form two
  • the secondary target graphics that is, the original target graphics that do not meet the preset process rules are adjusted to form the secondary target graphics that meet the preset process rules, and the optical proximity effect correction processing is performed on the secondary target graphics to obtain the corrected graphics.
  • the original target graphics are preprocessed to eliminate the graphic factors that cause the final simulated contour deformation to ensure that the simulated contours are close to the original target graphics, prevent serious distortion of the exposed graphics, and improve the final formation
  • the performance of the device can improve the production yield, and can effectively shorten the optical proximity effect correction cycle, and improve the exposure and lithography efficiency.
  • FIG. 1 is a schematic flowchart of a method for correcting optical proximity effect provided by an embodiment of the present disclosure
  • FIG. 2 is a schematic flowchart of another optical proximity effect correction method provided by an embodiment of the present disclosure
  • Fig. 3 is a schematic structural diagram of an original target graphic provided by an embodiment of the present disclosure.
  • FIG. 4 is a schematic structural diagram of another original target graphic provided by an embodiment of the present disclosure.
  • FIG. 5 is a schematic diagram of a comparative structure of an original target graphic and a secondary target graphic provided by an embodiment of the present disclosure
  • FIG. 6 is a schematic diagram of a comparative structure of another original target graphic and a secondary target graphic provided by an embodiment of the present disclosure
  • FIG. 7 is a schematic diagram of a comparative structure of another original target graphic and a secondary target graphic provided by an embodiment of the present disclosure
  • FIG. 8 is a schematic flowchart of another optical proximity effect correction method provided by an embodiment of the present disclosure.
  • FIG. 9 is a schematic structural diagram of another original target graphic provided by an embodiment of the present disclosure.
  • FIG. 10 is a schematic diagram of the structure of lines in a target graphic provided by an embodiment of the present disclosure.
  • FIG. 11 is a schematic flowchart of another optical proximity effect correction method provided by an embodiment of the present disclosure.
  • FIG. 12 is a schematic structural diagram of an optical auxiliary line provided by an embodiment of the present disclosure.
  • FIG. 13 is a schematic structural diagram of another optical auxiliary line provided by an embodiment of the present disclosure.
  • FIG. 14 is a schematic structural diagram of another optical auxiliary line provided by an embodiment of the present disclosure.
  • Fig. 15 is a schematic structural diagram of an optical proximity effect correction device provided by an embodiment of the present disclosure.
  • the critical dimensions of the key film layers at the 0.18 micron and below technology nodes for example, the active area layer, the gate oxide layer, and the metal connection layer are getting smaller and smaller, and some of the key dimensions are close to being smaller than the photolithography step.
  • the wavelength of the light used in the lithography step the pattern transfer is susceptible to deviations due to the influence of light, that is, the optical proximity effect.
  • the factor that forms the optical proximity effect is when the light beam passes through the mask pattern on the mask and is projected on On the photoresist, on the one hand, the energy distribution and phase distribution of the intensity spectrum of the beam have a certain distortion relative to the ideal image spectrum, that is, the diffraction effect.
  • the beam passes through the photoresist and is reflected back through the semiconductor substrate of the chip. Interference phenomenon occurs, so the exposure will be repeated, thereby changing the actual exposure of the photoresist layer.
  • the ideal pattern (target pattern) that needs to be formed on the film layer can be corrected by the optical proximity effect correction model to form a correction pattern, so that the exposure pattern (lithography pattern) formed on the film layer by the correction pattern is close to the target pattern, but Certain graphic settings in the target pattern cause serious distortion of the lithographic pattern formed after the correction of the target graphic, resulting in greater distortion. Therefore, the embodiment of the present disclosure preprocesses the graphic settings that are prone to distortion to set the target pattern before correction.
  • the preset process rules enable the target pattern to meet the preset process rules before performing optical proximity effect correction processing, so that the final lithography pattern is closer to the original target pattern, and the accuracy of the lithography pattern is enhanced.
  • FIG. 1 is a schematic flowchart of an optical proximity effect correction method provided by an embodiment of the present disclosure. As shown in FIG. 1, the optical proximity effect correction method includes the following step:
  • the original target pattern includes the pattern that the user ultimately wants to form on the chip or silicon wafer.
  • the mask pattern on the mask is pre-designed, so that the mask pattern is placed on the photoresist layer after the photolithography process. Form a lithographic pattern close to the original target pattern.
  • the final lithographic pattern formed on the silicon wafer is severely distorted, it is necessary to pre-process the original target pattern in advance to remove structural factors that cause the distortion of the lithographic pattern.
  • the graphic distortion is mainly manifested as line width deviation
  • the structure that causes the line width deviation will be adjusted, deleted or filled.
  • the graphic distortion is mainly manifested in continuous strips, the size and spacing of the target graphics will be adjusted. Reset the settings and adjust to the extent that it will not cause distortion of the photolithography pattern.
  • the preset process rules are set according to the relationship between the distortion and the target graphics, and the parts of the original target graphics that do not conform to the preset process rules are adjusted and processed to obtain the secondary target graphics. After the graphics are processed by the optical proximity effect correction, the structure that is prone to distortion will be avoided to a great extent.
  • the preprocessing of the original target graphics includes checking the original target graphics with preset process rules, and preprocessing the checked original target graphics that do not conform to the preset process rules.
  • S120 Perform optical proximity effect correction processing on the secondary target pattern to obtain a corrected pattern.
  • the target layout pattern can be corrected by the correction model to obtain the correction pattern.
  • the optical proximity correction model includes an optical model and a resist model.
  • the optical model is first used.
  • the above-mentioned optical model simulates the spatial light intensity distribution on the surface of the silicon wafer after the exposure beam irradiates the mask pattern and is diffracted by the lens group.
  • the photoresist model is used.
  • the model is to simulate the light intensity distribution on the photoresist on the surface of the silicon wafer.
  • the part of the photoresist above a certain exposure threshold undergoes a chemical reaction and is denatured, thereby being dissolved in the developer.
  • the photoresist model in this embodiment adopts a constant threshold resist model (constant threshold resist model), that is, the photoresist exposure reference threshold is fixed, compared to the variable threshold resist model (variable threshold resist model) Simplifying the photoresist model can avoid the complexity of obtaining the optical proximity correction model caused by the complicated photoresist model.
  • the correction pattern is simulated by the mask exposure process to obtain the simulated contour.
  • the simulated contour is the simulated exposure pattern or lithography pattern. Although the simulated contour is not exactly the same as the original target pattern, there is a certain error.
  • the embodiment enables the simulated contour to be further fitted to the original target pattern, and the optical proximity effect correction effect is improved.
  • S140 Calculate the deviation between the simulated contour and the original target graphic; determine whether the modified graphic meets the process requirements according to the deviation value.
  • the mask pattern can be formed according to the corrected pattern.
  • the lithography pattern formed by exposure of the mask pattern has a higher precision than the original target pattern. The graphics are close to improve the correction accuracy and mask quality.
  • the optical proximity effect correction method may further include: performing optical proximity effect correction processing on the secondary target pattern multiple times until the deviation value between the acquired simulated contour and the original target pattern meets the process requirements.
  • the original target pattern is preprocessed to form a secondary target pattern, so that the secondary target pattern is processed by the optical proximity effect correction process to form
  • the simulated contour of the image is closer to the original target pattern faster, the number of cycles from step S120 to step S140 is reduced, the number of calls of the optical proximity effect correction model is reduced, the speed of the optical proximity effect correction process is accelerated, and the correction accuracy is improved.
  • the original target pattern before the optical proximity effect correction is performed on the target pattern, the original target pattern is pre-processed, specifically, the original target pattern that will affect the accuracy of the exposure pattern finally exposed on the film layer is pre-corrected
  • adjust to form a secondary target pattern that is, adjust the original target pattern that does not meet the preset process rules to form a secondary target pattern that meets the preset process rules, and perform optical proximity effect correction processing on the secondary target pattern to obtain Correct the graphics, and simulate the exposure process of the corrected graphics to form a simulated contour. Compare the simulated contour with the original target graphics. If the deviation value meets the process requirements, the final accurate correction graphics can be determined, and the approximate The exposure pattern of the original target pattern.
  • the original target graphics are preprocessed to eliminate the graphic factors that cause the final simulated contour deformation to ensure that the simulated contours are close to the original target graphics, prevent serious distortion of the exposed graphics, and improve the final formation
  • the performance of the device improves the production yield.
  • the preset process rule may include: the main body does not include a block-shaped notch that is recessed; accordingly, the embodiment of the present disclosure specifically defines the preprocessing process of the original target pattern, as shown in FIG. 2, which is the original target pattern.
  • FIG. 2 A schematic flowchart of another optical proximity effect correction method provided by the disclosed embodiments. As shown in FIG. 2, the optical proximity effect correction method includes the following steps:
  • the target graphic is generally an irregular graphic, for example, the shape of a protruding long strip on the main body and a shape of recessed slits on the main body.
  • the preset process rule may include: the main body does not include a depressed block-shaped notch.
  • FIG. 3 is a schematic structural diagram of an original target pattern provided by an embodiment of the present disclosure.
  • Fig. 4 is a schematic structural diagram of another original target graphic provided by an embodiment of the present disclosure. As shown in Figures 3 and 4, the original pattern may include the blocky gap 111 formed by the depression on the main body 11. If the optical proximity effect correction is directly performed on the original target graphic, the blocky gap 111 will greatly affect the final result. The accuracy of the simulated contour causes the simulated contour to be distorted.
  • the contour formed by the dashed line in Fig. 3 is the simulated contour 12. It can be seen that the structure of the blocky gap 111 makes the original target graphic undergo the optical proximity effect to correct the distortion rate of the model. Because the simulated contour 12 cannot cover the basic main body 11, the simulated contour needs to be corrected by the optical proximity effect correction model multiple times to gradually improve the shape of the simulated contour. This will easily cause the entire optical proximity effect correction process to be more complicated and prolonged. The cycle time and the accuracy of the final mask pattern are not high enough. Therefore, in this embodiment, the original target graphics can be preprocessed first to eliminate the concave block-shaped notches 111 on the main body to form the secondary target graphics, as shown in FIG.
  • the secondary target pattern 13 can be extended along the contour line of the main body 11. As shown in FIG. 5, the concave blocky gap 111 on the original target pattern is filled to form the secondary target pattern 13. After the correction model is corrected, the formed simulated contour 12, the deviation between the simulated contour 12 and the original target pattern is relatively small, so that the simulated contour 12 can obtain a qualified mask pattern after a less number of optical proximity effect correction model corrections. .
  • the above step 210 that is, if the original target pattern includes a concave block-shaped notch on the main body, follow the contour of the main body
  • the line extends to form a secondary target pattern, so that the concave block-shaped gap on the main body is filled, including: if the original target graphic includes the block-shaped gap formed by the corner area of the two mutually perpendicular contour lines of the main body, follow the contour of the main body
  • the line fills the corner area to form a right angle area to form a secondary target pattern.
  • the corner or the block-shaped gap 111 at the corner is an important position limitation, and its change has a greater impact on the simulated contour 12.
  • the corner or the block-shaped gap 111 at the corner is filled first, so that the corner or The block-shaped notches 111 at the corners form a right-angled area to form a secondary target pattern 13 which makes the simulated contour 12 closer to the original target pattern and improves the correction accuracy.
  • the minimum size of the bulk gap 111 is less than or equal to 10 nm.
  • the minimum size of the block gap 111 is less than or equal to 10 nm, the greater the influence on the distortion of the simulated contour 12, so when the minimum size of the block gap 111 is less than or equal to 10 nm, the block gap 111 can be filled and repaired.
  • the block gap 111 is larger than 10 nm, the influence on the simulated contour 12 is small, and it can be treated as a normal main structure.
  • the block-shaped notches 111 recessed on the main body shown in FIGS. 4 and 5 are all rectangular in shape. Of course, the block-shaped notches 111 may also have other shapes.
  • FIG. 6 Fig. 6 is a schematic diagram of another comparative structure of the original target graphic and the secondary target graphic provided by an embodiment of the present disclosure.
  • the recessed block-shaped notch 111 may also include a plurality of notch units 111a arranged in a step-like manner.
  • the main body 11 includes stepped structures 112 corresponding to the notch units 111a one-to-one.
  • the secondary target graphics 13 is formed by extending along the contour line of the main body 11, so that the block-shaped gap 111 recessed on the main body 11 is filled, including:
  • the block-shaped notch 111 of the target pattern includes a plurality of notch units 111a arranged in steps, then the notch unit 111a is filled, and/or the step structure 112 corresponding to the notch unit 111a is removed to form a secondary target
  • the pattern 13 makes the minimum size of the concave block-shaped notch larger than 10 nm.
  • the block-shaped gap 111 of the original target pattern includes multiple gap units 111a, it may not be possible to directly fill the entire block-shaped gap 111.
  • the gap unit 111a can be filled or the step structure can be removed. 112 to reduce the number of notch units 111a corresponding to the block-shaped notch 111 and the number of stepped structures 112 on the main body 11, that is, to increase the minimum size of the block-shaped notch 111 by way of step reduction, for example, as shown in FIG.
  • the side length of the notch unit 111a of the original target pattern in 6 is the minimum size of the block-shaped notch 111, and the minimum size of the recessed block-shaped notch of the secondary target pattern 13 after processing is three times the side length of the notch unit 111a.
  • the minimum size of the blocky gap of the secondary target graphic 13 is increased, so that the simulated contour 12 is closer to the original target graphic, and the correction accuracy is improved.
  • the number of notch units 111a included in the original target pattern is two; the notch unit 111a corresponding to one step structure 112 is filled, and the other step structure 112 is removed to form Secondary target graphics 13.
  • the number of steps of the block step structure 112 is reduced, the minimum size of the block gap becomes larger, and the simulated contour 12 obtained from the secondary target graphic 13 is closer to the original target graphic, improving the correction accuracy .
  • FIG. 7 is a schematic diagram of a comparative structure of another original target graphic and a secondary target graphic provided by an embodiment of the present disclosure.
  • the original target graphic includes three notch units 111a;
  • the notch cells 111a corresponding to the two stepped structures 112 close to the main body 11 are filled to form the secondary target pattern 13.
  • the number of steps of the block stepped structure 112 is reduced, and the number of steps is reduced from three. It becomes one, the minimum size of the block-shaped gap is twice the side length of the gap unit 111a, and the simulated contour 12 obtained from the secondary target graphic 13 is closer to the original target graphic, which improves the correction accuracy.
  • S220 Perform optical proximity effect correction processing on the secondary target pattern to obtain a corrected pattern.
  • S240 Calculate the deviation between the simulated contour and the original target graphic; determine whether the modified graphic meets the process requirements according to the deviation value.
  • the concave blocky gap on the main body of the original target graphic is filled to form a secondary target graphic, and the secondary target graphic is used as the operating object to modify the optical proximity effect modification model.
  • the obtained simulated contour deviation rate is smaller, which is beneficial to shorten the optical proximity effect correction cycle, improve the accuracy of the final mask pattern, and thereby make the device production yield. Higher.
  • the preset process rule includes at least one of the following: the width of the line is greater than or equal to the width threshold; the width of the gap between adjacent lines is greater than or equal to the gap threshold; The distance between the center lines of the gap is greater than or equal to the interval threshold; correspondingly, the embodiment of the present disclosure specifically defines the preprocessing process of the original target pattern, as shown in FIG. 8, which is another optical fiber provided by the embodiment of the present disclosure.
  • the schematic flow chart of the proximity effect correction method as shown in Figure 8, the optical proximity effect correction method includes the following steps:
  • the original target pattern is preprocessed to form a secondary target pattern.
  • the specific process is to judge and test each preset process rule one by one, filter out the cases that do not meet the preset process rules, and compare the target graphics Perform resetting to form a secondary target pattern.
  • FIG. 9 is a schematic structural diagram of another original target graphic provided by an embodiment of the present disclosure. If the distance between the ends of the two lines 112 in FIG. 9 is too small, after the original target pattern is corrected by the optical proximity effect correction model, the formed simulated contour 12 is prone to streaks, causing errors in the mask image.
  • FIG. 10 is a target pattern provided by an embodiment of the present disclosure. Schematic diagram of the line structure. If the target graphic includes multiple parallel lines 112, the width d1 of the line may be defined to be greater than or equal to the width threshold, the width d2 of the gap between adjacent lines 112 may be greater than or equal to the gap threshold, and the center of the line 112 may also be defined The distance d3 between the line L1 and the center line L2 of the adjacent gap is greater than or equal to the interval threshold, so as to prevent the adjacent lines 112 from influencing each other, making the simulated contour prone to distortion.
  • the width and position of the line 112 of the target pattern are re-adjusted to form a secondary target pattern that conforms to the above-mentioned preset process rule.
  • the width threshold may be 50 nm; the gap threshold may be 100 nm; and the interval threshold may be 200 nm.
  • the width d1 of the line 112 is greater than or equal to 50 nm
  • the width d2 of the gap between adjacent lines 112 is greater than or equal to 100 nm
  • the distance d3 between the center line L1 of the line 112 and the center line L2 of the adjacent gap is greater than or equal to 200 nm
  • the adjacent lines 112 are not easily affected by each other, the correction rate of the optical proximity effect correction model is enhanced, the correction period is shortened, and the accuracy of the final formed lithography pattern is improved.
  • S320 Perform optical proximity effect correction processing on the secondary target graphic to obtain a corrected graphic.
  • S340 Calculate the deviation between the simulated contour and the original target graphic; determine whether the modified graphic meets the process requirements according to the deviation value.
  • the size and position of the lines in the original target graphic are set to form a secondary target graphic, so that the secondary target graphic meets the preset process rules, and the secondary target graphic is used as the correction object of the optical proximity effect correction model , So as to avoid the distortion and error caused by directly correcting the original target graphics, thereby improving the efficiency of the optical proximity effect correction process.
  • the original target pattern may also include optical auxiliary lines;
  • the preset process rules include at least one of the following Item: Among the two optical auxiliary lines extending perpendicularly, the gap between the side edge of the first optical auxiliary line and the end of the second optical auxiliary line is greater than or equal to the first auxiliary gap threshold; The width is greater than or equal to the first auxiliary width threshold; the width of the optical auxiliary line arranged in the gap between the two parts of the main body is less than or equal to the second auxiliary width threshold; and the optical auxiliary line close to the dummy pattern and the gap between the dummy pattern Greater than or equal to the second auxiliary gap threshold;
  • FIG. 11 is a schematic flowchart of another optical proximity effect correction method provided by the embodiment of the present disclosure. As shown in FIG.
  • the proximity effect correction method includes the following steps:
  • the original target pattern includes not only the target pattern used to form the lithography pattern, but also the optical auxiliary line used to assist the lithography pattern to enhance the process window.
  • the width of the optical auxiliary line is small. After exposure, Will not affect the exposure graphics. That is, the optical auxiliary lines do not form a simulated outline. However, if the size of the optical auxiliary line is too large, or the setting position is too close, it will easily cause the distortion of the simulated contour, and even directly form the exposure pattern.
  • the preset process rule includes at least one of the following.
  • FIG. 12 is a schematic structural diagram of an optical auxiliary line provided by an embodiment of the present disclosure.
  • the gap d4 between the side edge of the first optical auxiliary line 1131 and the end of the second optical auxiliary line 1132 is greater than or equal to the first auxiliary gap threshold;
  • the width d5 of the line 1131 is greater than or equal to the first auxiliary width threshold.
  • FIG. 13 is a schematic structural diagram of another optical auxiliary line provided by an embodiment of the present disclosure.
  • the width d6 of the optical auxiliary line 113 arranged in the gap between the two parts of the main body 11 is less than or equal to the second auxiliary width threshold; and, as shown in FIG. 14, FIG. 14 is another optical auxiliary line provided by an embodiment of the present disclosure.
  • the gap d7 between the optical auxiliary line 113 near the dummy pattern 114 and the dummy pattern 114 is greater than or equal to the second auxiliary gap threshold.
  • the optical auxiliary lines of the original target pattern are judged according to the foregoing preset process rules, and the optical auxiliary lines that do not meet the foregoing preset process rules are reset to form a secondary target pattern.
  • the first auxiliary gap threshold is 20 nm; the first auxiliary width threshold is 10 nm; the second auxiliary width threshold is 40 nm; and the second auxiliary gap threshold is 200 nm.
  • the gap d4 between the first optical auxiliary line 1131 and the second optical auxiliary line 1132 is greater than or equal to 20 nm, and the width d5 of the first optical auxiliary line 1131 is greater than or equal to 10 nm; the gap between the two parts of the main body 11
  • the width d6 of the optical auxiliary line 113 within is less than or equal to 40 nm; when the gap d7 between the optical auxiliary line 113 and the dummy pattern 114 is greater than or equal to 200 nm, the optical auxiliary line will not affect the exposure pattern and will not cause simulated contours distortion.
  • the size and position of the optical auxiliary lines that do not form the exposure pattern in the original exposure pattern are set to form a secondary target pattern, thereby improving the efficiency of the optical proximity effect correction process and improving the correction accuracy.
  • the preset process rules in this embodiment can simultaneously satisfy all the specific preset process rules mentioned in steps S210, S310, and S410, so as to improve the secondary target pattern obtained by the optical proximity correction model
  • the accuracy of the corrected graphics improves the accuracy of the optical proximity correction, and can effectively reduce the number of calls of the optical proximity correction model, reduce the optical proximity effect correction cycle, and obtain better correction effects, and improve the pass rate of the final product.
  • FIG. 15 is a structure of an optical proximity effect correction device provided by an embodiment of the present disclosure.
  • the schematic diagram, as shown in Figure 15, the optical proximity effect correction device includes:
  • the secondary processing module 21 is used to obtain the original target graphic and preprocess the original target graphic to form a secondary target graphic so that the secondary target graphic meets the preset process rules;
  • the correction module 22 is used to perform optical proximity effect correction processing on the secondary target graphics to obtain the corrected graphics
  • the contour module 23 is used to obtain the simulated contour of the original target graphic according to the corrected graphic
  • the deviation calculation module 24 calculates the deviation between the simulated contour and the original target graphic
  • the iteration module 25 is used to cyclically call the correction module and the contour module until the deviation value obtained by the deviation calculation module meets the process requirements.
  • the original target pattern before the optical proximity effect correction is performed on the target pattern, the original target pattern is pre-processed, specifically, the original target pattern that will affect the accuracy of the exposure pattern finally exposed on the film layer is pre-corrected
  • adjust to form a secondary target pattern that is, adjust the original target pattern that does not meet the preset process rules to form a secondary target pattern that meets the preset process rules, and perform optical proximity effect correction processing on the secondary target pattern to obtain Correct the graphics, and simulate the exposure process of the corrected graphics to form a simulated contour. Compare the simulated contour with the original target graphics. If the deviation value meets the process requirements, the final accurate correction graphics can be determined, and the approximate The exposure pattern of the original target pattern.
  • the original target graphics are preprocessed to eliminate the graphic factors that cause the final simulated contour deformation, ensure that the simulated contour covers the target contour, prevent serious distortion of the exposed graphics, and improve the final formed Device performance improves production yield.

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Abstract

一种光学临近效应修正方法及装置，其中，光学临近效应修正方法包括：获取原始目标图形，并对原始目标图形进行预处理，形成二次目标图形，使得二次目标图形满足预设工艺规则；将二次目标图形进行光学临近效应修正处理，获取修正图形；根据修正图形获取原始目标图形的模拟轮廓；计算模拟轮廓与原始目标图形之间的偏差；根据偏差值判断修正图形是否满足工艺需求。以此解决现有光学临近效应修正后，光刻图形失真严重的问题。

Description

光学临近效应修正方法及装置
本公开基于申请号为202010271782.8、申请日为2020年4月8日、发明名称为《一种光学临近效应修正方法及装置》的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本公开作为参考。
技术领域
本公开涉及半导体技术领域，尤其涉及一种光学临近效应修正方法及装置。
背景技术
随着集成电路元件缩小化以及集成化，各膜层的关键尺寸越来越小，在半导体工艺中，往往通过光刻将掩膜图形转移至硅片上形成各膜层图形，但是各元件的尺寸减小，光刻的准确率越低。
具体的，在光刻过程中，因为光的干涉效应和衍射效应，使得硅片上实际的光刻图形与掩膜图形之间存在一定的畸变和偏差，即光学临近效应(Optical Proximity Effect，OPE)。光学临近效应可能使得直角转角被圆角化、光刻图案的直线线宽增加或缩减等。为了避免由于OPE导致的光刻图案失真，现有技术采用了光学临近修正(Optical Proximity Correction，OPC)方法，对掩膜图形进行预先的修改，使得修改后的图形能够尽量弥补OPE造成的缺陷，然后将修改后的掩膜图形转移至硅片上产生光刻图形。
在实际应用中，由于原始目标图形的多样化，光刻图案和原始目标图形之间还存在差异，并且在某些情况下，会出现光刻图案轮廓无法覆盖目标轮廓，使得光刻图形失真严重的问题。图形畸变主要表现为线宽偏移、线条变短、遗漏图案或连条、角部变圆等特征。光刻图形的失真直接影响器件性能，从而降低生产成品率。
发明内容
本公开实施例提供了一种光学临近效应修正方法及装置，以解决现有光学临近效应修正后，光刻图形失真严重的问题。
第一方面，本公开实施例提供了一种光学临近效应修正方法，包括：
获取原始目标图形，并对所述原始目标图形进行预处理，形成二次目标图形，使得所述二次目标图形满足预设工艺规则；
将所述二次目标图形进行光学临近效应修正处理，获取修正图形；
根据所述修正图形获取所述原始目标图形的模拟轮廓；
计算所述模拟轮廓与所述原始目标图形之间的偏差；根据所述偏差值判断所述修正图形是否满足工艺需求。
第二方面，本公开实施例还提供了一种光学临近效应修正装置，用于执行本公开任意实施例提供的光学临近效应修正方法，包括：
二次处理模块，用于获取原始目标图形，并对所述原始目标图形进行预处理，形成二次目标图形，使得所述二次目标图形满足预设工艺规则；
修正模块，用于将所述二次目标图形进行光学临近效应修正处理，获取修正图形；
轮廓模块，用于根据所述修正图形获取所述原始目标图形的模拟轮廓；
偏差计算模块，计算所述模拟轮廓与所述原始目标图形之间的偏差；
迭代模块，用于循环调用所述修正模块和所述轮廓模块，直到所述偏差计算模块获取的所述偏差值满足工艺需求。
本公开中，在对目标图形进行光学临近效应修正之前，将原始目标图形进行预处理，将会影响最终曝光在膜层上的曝光图形的精准性的原始目标图形进行预先修正和调整，形成二次目标图形，也即，将不满足预设工艺规则的原始目标图形调整形成满足预设工艺规则的二次目标图形，并对二次目标图形进行光学临近效应修正处理，获取修正图形，并对修正图形进行模拟计算得到模拟轮廓，将该模拟轮廓与原始目标图形进行对比，若偏差值满足工艺需求的可确定最终的精准的修正图形，并 根据该修正图形获取模拟轮廓接近原始目标图形的曝光图形。相对于直接对原始目标图形进行光学临近效应修正，对原始目标图形进行预处理，消除引起最终模拟轮廓形变的图形因素，保证模拟轮廓接近原始目标图形，防止曝光图形失真严重的问题，提高最终形成的器件性能，提高生产成品率，并能够有效缩短光学临近效应修正周期，提高曝光和光刻效率。
附图说明
图1是本公开实施例提供的一种光学临近效应修正方法的流程示意图；
图2是本公开实施例提供的另一种光学临近效应修正方法的流程示意图；
图3是本公开实施例提供的一种原始目标图形的结构示意图；
图4是本公开实施例提供的另一种原始目标图形的结构示意图；
图5是本公开实施例提供的一种原始目标图形和二次目标图形的对比结构示意图；
图6是本公开实施例提供的另一种原始目标图形和二次目标图形的对比结构示意图；
图7是本公开实施例提供的另一种原始目标图形和二次目标图形的对比结构示意图；
图8是本公开实施例提供的另一种光学临近效应修正方法的流程示意图；
图9是本公开实施例提供的另一种原始目标图形的结构示意图；
图10是本公开实施例提供的一种目标图形中线条的结构示意图；
图11是本公开实施例提供的另一种光学临近效应修正方法的流程示意图；
图12是本公开实施例提供的一种光学辅助线条的结构示意图；
图13是本公开实施例提供的另一种光学辅助线条的结构示意图；
图14是本公开实施例提供的另一种光学辅助线条的结构示意图；
图15是本公开实施例提供的一种光学临近效应修正装置的结构示意 图。
具体实施方式
下面结合附图和实施例对本公开作进一步的详细说明。可以理解的是，此处所描述的具体实施例仅仅用于解释本公开，而非对本公开的限定。另外还需要说明的是，为了便于描述，附图中仅示出了与本公开相关的部分而非全部结构。
在半导体工艺过程中，在0.18微米及以下技术节点的关键膜层，例如，有源区层、栅氧化层、金属连接层的关键尺寸越来越小，有些关键尺寸已经接近设置小于光刻步骤中所使用的光波波长，在光刻步骤中，图形转移容易受到光线的影响而产生偏差，即光学临近效应，形成光学临近效应的因素是当光束透过掩膜版上的掩膜图形投影在光刻胶上时，一方面光束的强度频谱的能量分布和位相分布相对于理想像频谱有一定畸变，即衍射效应，另一方面，光束透过光刻胶再经过芯片的半导体基底反射回来，产生干涉现象，因此会反复曝光，从而改变光刻胶层的实际曝光量。一般可通过光学临近效应修正模型对需要形成在膜层上的理想图形(目标图形)进行修正，形成修正图形，使得修正图形形成在膜层上的曝光图形(光刻图形)接近目标图形，但是目标图形中某些图形设置，使得目标图形在修正后形成的光刻图形失真严重，产生较大畸变，所以本公开实施例对容易产生畸变的图形设置进行预处理，为修正前的目标图形设置预设工艺规则，使得目标图形满足预设工艺规则后再进行光学临近效应修正处理，使得最终形成的光刻图形更加贴近原始目标图形，增强光刻图形精准性。
具体的，本公开实施例提供了一种光学临近效应修正方法，图1是本公开实施例提供的一种光学临近效应修正方法的流程示意图，如图1所示，光学临近效应修正方法包括如下步骤：
S110、获取原始目标图形，并对原始目标图形进行预处理，形成二次目标图形，使得二次目标图形满足预设工艺规则。
原始目标图形包括用户最终想要形成在芯片或硅片上的图形，本实施例对掩膜版上的掩膜图形进行预设计，使得掩膜图形经过光刻工艺 后，在光刻胶层上形成接近原始目标图形的光刻图形。
为防止原始目标图形经过光学临近效应模型进行修正后最终形成在硅片上的光刻图形失真严重，则需要提前对原始目标图形进行预处理，去除导致光刻图形畸变的结构因素。在一些实施例中，若图形畸变主要表现为线宽偏移，则将引起线宽偏移的结构进行调整、删除或填补，若图形畸变主要表现在连条，则将目标图形的尺寸和间距重新设置，调整至不会引起光刻图形畸变的程度。在一些实施例中，根据畸变和目标图形之间的关系设定出预设工艺规则，将原始目标图形中不符合预设工艺规则的部分进行调整和处理，得到二次目标图形，二次目标图形经过光学临近效应修正处理后，会极大程度避开易产生畸变的结构。需要理解的是，所述对原始目标图形进行预处理包括对原始目标图形进行预设工艺规则的检查，对检查出来的不符合所述预设工艺规则的原始目标图形进行预处理。
S120、将二次目标图形进行光学临近效应修正处理，获取修正图形。
在一些实施例中，可通过修正模型对目标布局图形进行修正获得修正图形，例如光学邻近修正模型包括光学模型(optical model)与光刻胶模型(resist model)。在光学邻近修正过程中，先使用光学模型，上述光学模型是模拟曝光光束照射掩膜图形，通过透镜组发生衍射后在硅片表面的空间光强分布，接着使用光刻胶模型，光刻胶模型是模拟上述硅片表面的光强分布在光刻胶上，高于一定曝光阈值的光刻胶部分发生化学反应而变性，从而被溶于显影液。本实施例中的光刻胶模型采用固定阈值的光刻胶模型(constant threshold resist model)，即光刻胶曝光参考阈值固定，相对于可变曝光阈值的光刻胶模型(variable threshold resist model)，简化光刻胶模型可以避免复杂光刻胶模型对光学邻近修正模型的获取造成的复杂化。
S130、根据修正图形获取原始目标图形的模拟轮廓。
将修正图形进行掩膜版曝光进程的模拟，获取模拟轮廓，该模拟轮廓即为模拟的曝光图形或光刻图形，虽然模拟轮廓与原始目标图形不是完全相同的，而存在一定的误差，但是本实施例使得模拟轮廓能够进一 步贴合原始目标图形，提高光学临近效应修正效果。
S140、计算模拟轮廓与原始目标图形之间的偏差；根据偏差值判断修正图形是否满足工艺需求。
若模拟轮廓与原始目标图形之间的偏差满足工艺需求，则说明光学临近效应修正效果合格，可根据修正图形形成掩膜图案，该掩膜图案曝光形成的光刻图形精度较高，与原始目标图形贴近，提高修正精度和掩膜质量。
在一些实施例中，光学临近效应修正方法还可以包括：多次对二次目标图形进行光学临近效应修正处理，直至获取的模拟轮廓与原始目标图形之间的偏差值满足工艺需求。
在一些实施例中，可能无法经过一次光学临近效应修正处理就直接得到最终的修正图形，更多的情况是，需要多次进行光学临近效应修正处理得到较为精确的修正图形来形成掩膜图案，所以需要多次执行步骤S120至步骤S140，得到最终的修正图形，而本实施例中，对原始目标图形进行预处理形成二次目标图形，使得二次目标图形经过光学临近效应修正处理后，形成的模拟轮廓更快的贴近原始目标图形，减少步骤S120至步骤S140的循环次数，减少光学临近效应修正模型的调用次数，加快光学临近效应修正过程的速度，并提高修正精度。
本公开实施例中，在对目标图形进行光学临近效应修正之前，将原始目标图形进行预处理，具体的，将会影响最终曝光在膜层上的曝光图形的精准性的原始目标图形进行预先修正和调整，形成二次目标图形，也即，将不满足预设工艺规则的原始目标图形调整形成满足预设工艺规则的二次目标图形，并对二次目标图形进行光学临近效应修正处理，获取修正图形，并对修正图形进行模拟曝光过程，形成模拟轮廓，将该模拟轮廓与原始目标图形进行对比，若偏差值满足工艺需求的可确定最终的精准的修正图形，并根据该修正图形获取接近原始目标图形的曝光图形。相对于直接对原始目标图形进行光学临近效应修正，对原始目标图形进行预处理，消除引起最终模拟轮廓形变的图形因素，保证模拟轮廓接近原始目标图形，防止曝光图形失真严重的问题，提高最终形成的器件性能，提高生产成品率。
在一些实施例中，预设工艺规则可以包括：主体上不包括凹陷的块状缺口；相应的，本公开实施例对原始目标图形进行预处理过程进行具体限定，如图2，图2是本公开实施例提供的另一种光学临近效应修正方法的流程示意图，如图2所示，光学临近效应修正方法包括如下步骤：
S210、获取原始目标图形，若原始目标图形包括主体上凹陷的块状缺口，则沿主体的轮廓线延伸形成二次目标图形，使得主体上凹陷的块状缺口被填充。
目标图形一般为不规则图形，例如，主体上凸出长条形的形状，以及主体上凹陷出狭缝的形状。在一些实施例中，预设工艺规则可以包括：主体上不包括凹陷的块状缺口，图3是本公开实施例提供的一种原始目标图形的结构示意图。图4是本公开实施例提供的另一种原始目标图形的结构示意图。如图3和图4所示，原始图形可能包括主体11上凹陷形成的块状缺口111，若直接对原始目标图形进行光学临近效应修正，则上述块状缺口111会极大的影响最终得到的模拟轮廓的准确性，引起模拟轮廓发生畸变，如图3所示，图3中虚线形成的轮廓为模拟轮廓12，可知块状缺口111的结构使得原始目标图形经过光学临近效应修正模型畸变率较大，模拟轮廓12都不能覆盖基本的主体11，使得模拟轮廓需要多次经过光学临近效应修正模型的修正，才能逐渐改善模拟轮廓的形状，则容易造成整个光学临近效应修正过程比较复杂，延长了周期时间，并且最终形成的掩膜图形的精准度也不够高。所以本实施例中，可首先将原始目标图形进行预处理，消除主体上凹陷的块状缺口111，形成二次目标图形，如图5所示，图5是本公开实施例提供的一种原始目标图形和二次目标图形的对比结构示意图。可沿主体11的轮廓线延长形成二次目标图形13，如图5所示，原始目标图形上凹陷的块状缺口111被填充形成二次目标图形13，将二次目标图形13经过光学临近效应修正模型修正后，形成的模拟轮廓12，模拟轮廓12与原始目标图形之间的偏差较小，使得模拟轮廓12经过较少次数的光学临近效应修正模型修正后，即可获取合格的掩膜图形。
在上述实施例的基础上，继续参考5所示，若块状缺口111形成在转角或拐角处，上述步骤210，也即若原始目标图形包括主体上凹陷的块状缺口，则沿主体的轮廓线延伸形成二次目标图形，使得主体上凹陷的块状缺口被填充，包括：若原始目标图形包括主体的两条相互垂直的轮廓线的转角区域凹陷形成的块状缺口，则沿主体的轮廓线将转角区域填充形成直角区域，形成二次目标图形。转角或拐角处的块状缺口111作为一个重要的位置限定处，其变化对模拟轮廓12的影响较大，则本实施例中先将转角或拐角处的块状缺口111进行填充，使得转角或拐角处的块状缺口111形成直角区域，形成二次目标图形13，该二次目标图形13使得模拟轮廓12更贴近原始目标图形，提高修正精度。
在一些实施例中，块状缺口111的最小尺寸小于或等于10nm。当块状缺口111的最小尺寸小于或等于10nm时，对模拟轮廓12的畸变影响越大，所以当块状缺口111的最小尺寸小于或等于10nm时，可对块状缺口111进行填充修复处理，而当块状缺口111大于10nm，对模拟轮廓12的影响较小，可作为正常的主体结构进行处理。
图4和图5中示出的主体上凹陷的块状缺口111均为矩形形状，当然块状缺口111还可以存在其他形状，在本实施例的一种具体实现方式中，如图6所示，图6是本公开实施例提供的另一种原始目标图形和二次目标图形的对比结构示意图。凹陷的块状缺口111还可以包括多个台阶状排布的缺口单元111a，对应的，主体11上包括与所述缺口单元111a一一对应的的台阶状结构112。对应的，若原始目标图形包括主体11上凹陷的块状缺口111，则沿主体11的轮廓线延伸形成二次目标图形13，使得主体11上凹陷的块状缺口111被填充，包括：若原始目标图形的块状缺口111包括多个台阶状排布的缺口单元111a，则对缺口单元111a进行填充处理，和/或，对缺口单元111a对应的台阶结构112进行移除处理，形成二次目标图形13，使得凹陷的块状缺口的最小尺寸大于10nm。
如图6所示，当原始目标图形的块状缺口111包括多个缺口单元111a时，可能无法直接将整个块状缺口111进行填充，则本实施例可通过填充缺口单元111a或移除台阶结构112的方式，降低该块状缺口111 对应的缺口单元111a和主体11上的台阶状结构112的数量，也即，通过降阶的方式，增大该块状缺口111的最小尺寸，例如，图6中原始目标图形的缺口单元111a的边长为块状缺口111的最小尺寸，经过处理之后的二次目标图形13的凹陷的块状缺口的最小尺寸为缺口单元111a的边长的三倍，从而增大了二次目标图形13的块状缺口的最小尺寸，从而使得模拟轮廓12更贴近原始目标图形，提高修正精度。
在一些实施例中，继续参考图6，原始目标图形包括的缺口单元111a的个数为2个；其中一个台阶结构112对应的缺口单元111a被填充，另一个台阶结构112被移除，以形成二次目标图形13。则对比原始目标图形和二次目标图形13，块台阶结构112的台阶数降低，块状缺口的最小尺寸变大，由二次目标图形13得到的模拟轮廓12更贴近原始目标图形，提高修正精度。
在一些实施例中，参考图7，图7是本公开实施例提供的另一种原始目标图形和二次目标图形的对比结构示意图，原始目标图形包括的缺口单元111a的个数为3个；靠近主体11的两个台阶结构112对应的缺口单元111a被填充，以形成二次目标图形13，对比原始目标图形和二次目标图形13，块台阶结构112的台阶数降低，台阶数由三个变为一个，块状缺口的最小尺寸为缺口单元111a的边长的两倍，由该二次目标图形13得到的模拟轮廓12更贴近原始目标图形，提高修正精度。
S220、将二次目标图形进行光学临近效应修正处理，获取修正图形。
S230、根据修正图形获取原始目标图形的模拟轮廓。
S240、计算模拟轮廓与原始目标图形之间的偏差；根据偏差值判断修正图形是否满足工艺需求。
本实施例中，通过对原始目标图形预处理，填充原始目标图形中主体上凹陷的块状缺口，形成二次目标图形，并将该二次目标图形作为操作对象进行光学临近效应修改模型的修正，而不是将原始目标图形进行光学临近效应修改模型的修正，使得得到的模拟轮廓偏差率较小，有利于缩短光学临近效应修正周期，提高最终掩膜图形的精准度，进而使得器件制作良率较高。
在一些实施例中，预设工艺规则包括下述至少一项：线条的宽度大于或等于宽度阈值；相邻线条之间间隙的宽度大于或等于间隙阈值；以及，线条的中心线与相邻的间隙的中心线之间的距离大于或等于间隔阈值；相应的，本公开实施例对原始目标图形进行预处理过程进行具体限定，如图8，图8是本公开实施例提供的另一种光学临近效应修正方法的流程示意图，如图8所示，光学临近效应修正方法包括如下步骤：
S310、获取原始目标图形，若原始目标图形的主体不满足预设工艺规则，则对主体进行重新设置，以满足预设工艺规则，形成二次目标图形。
本实施例中，对原始目标图形进行预处理，形成二次目标图形，具体过程为对各个预设工艺规则进行逐一判断和检测，筛选出不符合各预设工艺规则的情况，并对目标图形进行重新设置，形成二次目标图形。
本实施例中，对原始目标图形的线条的尺寸和设置进行设置，以减小最终形成的模拟轮廓产生的畸变。示例性的，如图9所示，图9是本公开实施例提供的另一种原始目标图形的结构示意图。若图9中两个线条112端部的间距过小，将原始目标图形进行光学邻近效应修正模型的修正后，形成的模拟轮廓12容易发生连条的情况，造成掩膜图像出现误差。
本实施例中，设置了预设工艺规则，预设工艺规则可包括下述至少一项，在一些实施例中，如图10所示，图10是本公开实施例提供的一种目标图形中线条的结构示意图。若目标图形包括多条平行设置的线条112，可限定线条的宽度d1大于或等于宽度阈值,也可限定相邻线条112之间间隙的宽度d2大于或等于间隙阈值,还可以限定线条112的中心线L1与相邻的间隙的中心线L2之间的距离d3大于或等于间隔阈值,从而防止相邻设置的线条112之间相互影响，使得模拟轮廓容易产生畸变。所以，若原始目标图形中存在不符合上述预设工艺规则的至少一项，则重新对目标图形的线条112的宽度和位置进行调整，形成符合上述预设工艺规则的二次目标图形。
在一些实施例中，宽度阈值可以为50nm；间隙阈值可以为100nm； 间隔阈值可以为200nm。当线条112的宽度d1大于或等于50nm，相邻线条112之间间隙的宽度d2大于或等于100nm，线条112的中心线L1与相邻的间隙的中心线L2之间的距离d3大于或等于200nm时，相邻线条112之间不易相互影响，增强了光学临近效应修正模型的修正速率，缩短修正周期，提高最终形成的光刻图形的精准率。
S320、将二次目标图形进行光学临近效应修正处理，获取修正图形。
S330、根据修正图形获取原始目标图形的模拟轮廓。
S340、计算模拟轮廓与原始目标图形之间的偏差；根据偏差值判断修正图形是否满足工艺需求。
本实施例中，对原始目标图形中的线条的尺寸和位置进行设置，形成二次目标图形，使得二次目标图形满足预设工艺规则，将二次目标图形作为光学临近效应修正模型的修正对象，从而避免直接对原始目标图形进行修正而产生的的畸变和误差，从而提高光学临近效应修正过程的效率。
上述步骤S210至步骤S240,以及步骤S310至步骤S340，均是针对曝光图形的尺寸和位置设置，在一些实施例中，原始目标图形还可以包括光学辅助线条；预设工艺规则包括下述至少一项：延伸方向垂直的两条光学辅助线条中，第一光学辅助线条的侧边边缘与第二光学辅助线条的端部之间的间隙大于或等于第一辅助间隙阈值；第一光学辅助线条的宽度大于或等于第一辅助宽度阈值；设置于两部分主体之间间隙内的光学辅助线的宽度小于或等于第二辅助宽度阈值；以及，靠近虚设图形的光学辅助线条与虚设图形之间的间隙大于或等于第二辅助间隙阈值；
相应的，本公开实施例对原始目标图形进行预处理过程进行描述，如图11，图11是本公开实施例提供的另一种光学临近效应修正方法的流程示意图，如图11所示，光学临近效应修正方法包括如下步骤：
S410、获取原始目标图形，若原始目标图形的光学辅助线条不满足预设工艺规则，则对光学辅助线条进行重新设置，以满足预设工艺规则，形成二次目标图形。
在原始目标图形中，不仅包括用于形成光刻图形的目标图形，包括用于对光刻图形进行辅助，以增强工艺窗口的光学辅助线条，该光学辅助线条的宽度较小，经过曝光后，不会影响曝光图形。也即，光学辅助线条不会形成模拟轮廓。但是若光学辅助线条的尺寸过大，或者设置位置过近，也容易会引起模拟轮廓的畸变，甚至直接形成曝光图案。
本实施例中，预设工艺规则包括下述至少一项，在一些实施例中，如图12所示，图12是本公开实施例提供的一种光学辅助线条的结构示意图。延伸方向垂直的两条光学辅助线条113中，第一光学辅助线条1131的侧边边缘与第二光学辅助线条1132的端部之间的间隙d4大于或等于第一辅助间隙阈值；第一光学辅助线条1131的宽度d5大于或等于第一辅助宽度阈值。如图13所示，图13是本公开实施例提供的另一种光学辅助线条的结构示意图。设置于两部分主体11之间间隙内的光学辅助线条113的宽度d6小于或等于第二辅助宽度阈值；以及，如图14所示，图14是本公开实施例提供的另一种光学辅助线条的结构示意图，靠近虚设图形114的光学辅助线条113与虚设图形114之间的间隙d7大于或等于第二辅助间隙阈值。本实施例将原始目标图形的光学辅助线条按照上述预设工艺规则进行判断，并将不符合上述预设工艺规则的光学辅助线条重新设置，形成二次目标图形。
在一些实施例中，第一辅助间隙阈值为20nm；第一辅助宽度阈值为10nm；第二辅助宽度阈值为40nm；第二辅助间隙阈值为200nm。当相互垂直的，第一光学辅助线条1131和第二光学辅助线条1132之间的间隙d4大于或等于20nm，并且第一光学辅助线条1131的宽度d5大于或等于10nm；两部分主体11之间间隙内的光学辅助线条113的宽度d6小于或等于40nm；光学辅助线条113与虚设图形114之间的间隙d7大于或等于200nm时，光学辅助线条会不对曝光图形产生影响，且不会引起模拟轮廓的畸变。
S420、将二次目标图形进行光学临近效应修正处理，获取修正图形。
S430、根据修正图形获取原始目标图形的模拟轮廓。
S440、计算模拟轮廓与原始目标图形之间的偏差；根据偏差值判断 修正图形是否满足工艺需求。
本实施例中，对原始曝光图形中不形成曝光图形的光学辅助线条的尺寸和位置进行设置，形成二次目标图形，从而提高光学临近效应修正过程的效率，并提高修正精度。
在上述实施例的基础上，本实施例中的预设工艺规则可同时满足步骤S210、S310和S410中提及的所有的具体预设工艺规则，以提高二次目标图形经过光学临近修正模型得到的修正图形的精准度，提高光学临近修正的准确性，并能够有效缩减光学临近修正模型的调用次数，减小光学临近效应修正周期，并获取更好的修正效果，提高最终产品的合格率。
基于同一构思，本公开实施例还提供一种光学临近效应修正装置，可执行本公开任意实施例提供的光学临近效应修正，图15是本公开实施例提供的一种光学临近效应修正装置的结构示意图，如图15所示，光学临近效应修正装置包括：
二次处理模块21，用于获取原始目标图形，并对原始目标图形进行预处理，形成二次目标图形，使得二次目标图形满足预设工艺规则；
修正模块22，用于将二次目标图形进行光学临近效应修正处理，获取修正图形；
轮廓模块23，用于根据修正图形获取原始目标图形的模拟轮廓；
偏差计算模块24，计算模拟轮廓与原始目标图形之间的偏差；
迭代模块25，用于循环调用修正模块和轮廓模块，直到偏差计算模块获取的偏差值满足工艺需求。
本公开实施例中，在对目标图形进行光学临近效应修正之前，将原始目标图形进行预处理，具体的，将会影响最终曝光在膜层上的曝光图形的精准性的原始目标图形进行预先修正和调整，形成二次目标图形，也即，将不满足预设工艺规则的原始目标图形调整形成满足预设工艺规则的二次目标图形，并对二次目标图形进行光学临近效应修正处理，获取修正图形，并对修正图形进行模拟曝光过程，形成模拟轮廓，将该模拟轮廓与原始目标图形进行对比，若偏差值满足工艺需求的可确定最终 的精准的修正图形，并根据该修正图形获取接近原始目标图形的曝光图形。相对于直接对原始目标图形进行光学临近效应修正，对原始目标图形进行预处理，消除引起最终模拟轮廓形变的图形因素，保证模拟轮廓覆盖目标轮廓，防止曝光图形失真严重的问题，提高最终形成的器件性能，提高生产成品率。
注意，上述仅为本公开的较佳实施例及所运用技术原理。本领域技术人员会理解，本公开不限于这里所述的特定实施例，对本领域技术人员来说能够进行各种明显的变化、重新调整和替代而不会脱离本公开的保护范围。因此，虽然通过以上实施例对本公开进行了较为详细的说明，但是本公开不仅仅限于以上实施例，在不脱离本公开构思的情况下，还可以包括更多其他等效实施例，而本公开的范围由所附的权利要求范围决定。

Claims (12)

  1. 一种光学临近效应修正方法，其中，包括：
    获取原始目标图形，并对所述原始目标图形进行预处理，形成二次目标图形，使得所述二次目标图形满足预设工艺规则；
    将所述二次目标图形进行光学临近效应修正处理，获取修正图形；
    根据所述修正图形获取所述原始目标图形的模拟轮廓；
    计算所述模拟轮廓与所述原始目标图形之间的偏差；
    根据所述偏差值判断所述修正图形是否满足工艺需求。
  2. 根据权利要求1所述的光学临近效应修正方法，其中，所述预设工艺规则包括：主体上不包括凹陷的块状缺口；
    对所述原始目标图形进行预处理，形成二次目标图形，包括：
    基于所述原始目标图形包括所述主体上凹陷的块状缺口，沿所述主体的轮廓线延伸形成所述二次目标图形，使得所述主体上凹陷的块状缺口被填充。
  3. 根据权利要求2所述的光学临近效应修正方法，其中，基于所述原始目标图形包括所述主体上凹陷的块状缺口，沿所述主体的轮廓线延伸形成所述二次目标图形，使得所述主体上凹陷的块状缺口被填充，包括：
    基于所述原始目标图形包括所述主体的两条相互垂直的轮廓线的转角区域凹陷形成的块状缺口，沿所述主体的轮廓线将所述转角区域填充形成直角区域，形成所述二次目标图形。
  4. 根据权利要求2所述的光学临近效应修正方法，其中，
    所述块状缺口的最小尺寸小于或等于10nm。
  5. 根据权利要求2所述的光学临近效应修正方法，其中，所述凹陷的块状缺口包括多个台阶状排布的缺口单元；所述缺口单元与所述主体上台阶状结构一一对应；
    基于所述原始目标图形包括所述主体上凹陷的块状缺口，沿所述主体的轮廓线延伸形成所述二次目标图形，使得所述主体上凹陷的块状缺口被填充，包括：
    基于所述原始目标图形的块状缺口包括多个台阶状排布的缺口单 元，对所述缺口单元进行填充处理，和/或，对所述缺口单元对应的所述台阶结构进行移除处理，形成所述二次目标图形，使得所述主体上凹陷的块状缺口的最小尺寸大于10nm。
  6. 根据权利要求5所述的光学临近效应修正方法，其中，所述原始目标图形包括的所述缺口单元的个数为2个，所述缺口单元中一个缺口单元被填充，另一个缺口单元对应的台阶结构被移除，以形成所述二次目标图形。
  7. 根据权利要求5所述的光学临近效应修正方法，其中，所述原始目标图形包括的缺口单元的个数为3个，靠近所述主体的两个所述台阶结构对应的缺口单元被填充，以形成所述二次目标图形。
  8. 根据权利要求1所述的光学临近效应修正方法，其中，所述预设工艺规则包括下述至少一项：
    线条的宽度大于或等于宽度阈值；
    相邻线条之间间隙的宽度大于或等于间隙阈值；以及，
    所述线条的中心线与相邻的所述间隙的中心线之间的距离大于或等于间隔阈值；
    对所述原始目标图形进行预处理，形成二次目标图形，包括：
    响应于所述原始目标图形的主体不满足所述预设工艺规则，对所述主体进行重新设置，以满足所述预设工艺规则，形成所述二次目标图形。
  9. 根据权利要求1所述的光学临近效应修正方法，其中，所述原始目标图形包括光学辅助线条，所述光学辅助线条包括延伸方向垂直的第一光学辅助线条和第二光学辅助线条；所述预设工艺规则包括下述至少一项：
    所述第一光学辅助线条的侧边边缘与所述第二光学辅助线条的端部之间的间隙大于或等于第一辅助间隙阈值；
    所述第一光学辅助线条的宽度大于或等于第一辅助宽度阈值；
    设置于两部分主体之间间隙内的光学辅助线条的宽度小于或等于第二辅助宽度阈值；以及，
    靠近虚设图形的光学辅助线条与所述虚设图形之间的间隙大于或等 于第二辅助间隙阈值；
    对所述原始目标图形进行预处理，形成二次目标图形，包括：
    响应于所述原始目标图形的光学辅助线条不满足所述预设工艺规则，对所述原始目标图形的光学辅助线条进行重新设置，以满足所述预设工艺规则，形成所述二次目标图形。
  10. 根据权利要求9所述的光学临近效应修正方法，其中，
    所述第一辅助间隙阈值为20nm；所述第一辅助宽度阈值为10nm；所述第二辅助宽度阈值为40nm；所述第二辅助间隙阈值为200nm。
  11. 根据权利要求1所述的光学临近效应修正方法，其中，还包括：
    多次对所述二次目标图形进行光学临近效应修正处理，直至获取的模拟轮廓与所述原始目标图形之间的偏差值满足工艺需求。
  12. 一种光学临近效应修正装置，其中，可用于执行上述权利要求1所述的光学临近效应修正方法，包括：
    二次处理模块，用于获取原始目标图形，并对所述原始目标图形进行预处理，形成二次目标图形，使得所述二次目标图形满足预设工艺规则；
    修正模块，用于将所述二次目标图形进行光学临近效应修正处理，获取修正图形；
    轮廓模块，用于根据所述修正图形获取所述原始目标图形的模拟轮廓；
    偏差计算模块，计算所述模拟轮廓与所述原始目标图形之间的偏差；
    迭代模块，用于循环调用所述修正模块和所述轮廓模块，直到所述偏差计算模块获取的所述偏差值满足工艺需求。
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