Establishment method and device of OPC (Optical Proximity Correction) model, optical proximity correction method and equipment, and storage medium

Abstract

The invention discloses an OPC model establishing method and device, an optical proximity correction method and equipment and a storage medium, and the method comprises the steps: forming a semiconductor structure which is provided with a graphical layer; obtaining the contour of a graph in the graphical layer; and screening the measurement data of the graphical layer according to the contour of the obtained graph. And screening the measurement data of the graphical layer on the basis of the obtained contour of the graph in the graphical layer, so that the data browsing time can be effectively shortened, the number of model iterations can be reduced, and the OPC modeling efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of photolithography, and in particular to an OPC model establishment method and device, an optical proximity correction method and equipment, and a storage medium. Background Art

[0002] In the semiconductor manufacturing process, in order to transfer the circuit pattern of an integrated circuit (IC) to a semiconductor chip, the circuit pattern of the integrated circuit needs to be designed as a mask pattern, and then the mask pattern is transferred from the mask surface to the semiconductor chip.

[0003] As the critical dimension (CD) of integrated circuits shrinks and is affected by the resolution limit of the optical exposure tool (OET), the optical proximity effect (OPE) is easily generated when the high-density mask pattern is exposed for pattern transfer, causing defects in the mask pattern transfer. To address the problem of optical proximity effect, a method currently commonly used in the industry is optical proximity correction (OPC), which reduces the deviation of the lithography pattern obtained by exposure by changing the shape of the original layout pattern.

[0004] In model-based OPC, building an OPC model requires a large amount of graphic data containing different feature types to ensure sufficient model coverage. Each feature graphic also needs to cover CDs of different sizes to ensure the accuracy of the model. In other words, building an OPC model requires a large amount of graphic data.

[0005] However, existing methods often have the problem of low efficiency in screening the graphic data used in building OPC models. Summary of the invention

[0006] The problem solved by the present invention is how to improve the OPC model building efficiency.

[0007] To solve the above problems, the present invention provides a method for establishing an OPC model, comprising:

[0008] A semiconductor structure is formed, wherein the semiconductor structure has a patterned layer; an outline of a pattern in the patterned layer is obtained; and measurement data of the patterned layer is screened according to the obtained outline of the pattern.

[0009] Optionally, the method further includes: performing model operation according to the screened measurement data, wherein the model operation includes: establishing an OPC model and verifying the OPC model.

[0010] Optionally, the method further includes: after filtering the measurement data of the graphic layer, and before performing model operation based on the filtered measurement data, reviewing the filtered measurement data.

[0011] Optionally, obtaining the outline of the graphics in the graphic layer includes: obtaining an image of the graphic layer; and extracting the outline of the graphics in the graphic layer according to the graphics in the graphic layer.

[0012] Optionally, in the step of obtaining the image of the patterned layer, the image of the patterned layer is obtained by a measuring machine.

[0013] Optionally, in the step of obtaining the image of the patterned layer by using a measuring machine, the measuring machine is a scanning electron microscope.

[0014] Optionally, in the step of obtaining the image of the patterned layer by using a measuring machine, the measuring machine is a feature size scanning electron microscope.

[0015] Optionally, it also includes: measuring along a preset measurement direction to obtain measurement data of the graphic layer; in the step of obtaining the contour of the graphic in the graphic layer, obtaining the inner contour and the outer contour of the graphic in the graphic layer; according to the contour of the obtained graphic, the step of screening the measurement data of the graphic layer includes: obtaining the contour difference in the measurement direction according to the inner contour and the outer contour of the graphic in the graphic layer, the contour difference in the measurement direction being the difference between the inner contour and the outer contour in the measurement direction; judging whether the measurement data of the graphic layer is invalid according to the contour difference in the measurement direction.

[0016] Optionally, in the step of determining whether the measurement data of the graphic layer is invalid, it is determined whether the measurement data of the graphic layer is invalid based on a ratio of a contour difference in the measurement direction to the measurement data in the measurement direction.

[0017] Optionally, in the step of determining whether the measurement data of the graphic layer is invalid, the measurement data of the graphic layer is determined to be invalid based on the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction, combined with the dimension of the graphics in the graphic layer.

[0018] Optionally, the step of screening the measurement data of the graphic layer according to the contour of the obtained graphic also includes: when judging that the measurement data of the graphic layer is valid data, judging whether the measurement data of the graphic layer is modeling data or verification data according to the contour difference in the measurement direction.

[0019] Optionally, the step of performing model operation according to the screened measurement data includes: establishing an OPC model according to the modeling data; and verifying the OPC model according to the verification data.

[0020] In addition, the present invention also provides an optical proximity correction method, comprising:

[0021] Obtain a design layout; establish an OPC model, wherein the OPC model is established by the establishment method of the present invention; and use the OPC model to modify the design layout to obtain a tape-out layout.

[0022] Accordingly, the present invention also provides an OPC model establishment device, comprising:

[0023] A process unit, wherein the process unit is suitable for forming a semiconductor structure, wherein the semiconductor structure has a patterned layer; a measurement unit, wherein the measurement unit is suitable for obtaining the contour of a pattern in the patterned layer; and a screening unit, wherein the screening unit is suitable for screening the measurement data of the patterned layer according to the contour of the obtained pattern.

[0024] Optionally, it further includes: a modeling unit, wherein the modeling unit is suitable for performing model operations according to the screened measurement data, wherein the model operations include: one of establishing an OPC model and verifying the OPC model.

[0025] Optionally, it further includes: an audit unit, which is suitable for auditing the screened measurement data.

[0026] Optionally, the measurement unit comprises: an imager, which is suitable for obtaining an image of the patterned layer; and an extractor, which is suitable for extracting the contour of the pattern in the patterned layer according to the pattern of the patterned layer.

[0027] Optionally, the measuring unit is also suitable for measuring along a preset measuring direction to obtain measurement data of the graphic layer; the measuring unit is suitable for obtaining the inner contour and the outer contour of the graphic in the graphic layer; the screening unit includes: an interpolator, the interpolator is suitable for obtaining the contour difference in the measuring direction according to the inner contour and the outer contour of the graphic in the graphic layer, and the contour difference in the measuring direction is the difference between the inner contour and the outer contour in the measuring direction; a judger, the judger is suitable for judging whether the measurement data of the graphic layer is invalid according to the contour difference in the measuring direction.

[0028] Optionally, the screening unit further includes: a classifier, and when the judger judges that the measurement data of the graphic layer is valid data, the classifier judges whether the measurement data of the graphic layer is modeling data or verification data according to the contour difference in the measurement direction.

[0029] In addition, the present invention also provides an optical proximity correction device, comprising:

[0030] An establishing device, wherein the establishing device is suitable for establishing an OPC model, and the establishing device is the establishing device of the present invention; an acquiring device, wherein the acquiring device is suitable for acquiring a design layout; and a correcting device, wherein the correcting device is suitable for using the OPC model to correct the design layout to obtain a tape-out layout.

[0031] Moreover, the present invention also provides a storage medium on which a computer program is stored, and the computer program is executed by a processor to implement the steps of the establishment method of the present invention.

[0032] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0033] In the technical solution of the present invention, based on the obtained contour of the graphics in the graphic layer, the measurement data of the graphic layer is screened, which can effectively shorten the data browsing time, reduce the number of model iterations, and effectively improve the OPC modeling efficiency.

[0034] In an optional solution of the present invention, based on the difference between the inner contour and the outer contour in the measurement direction, it is judged whether the measurement data of the graphic layer is valid to implement data screening, which can ensure that data screening has a standard to follow and reduce repeated screening caused by data misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is an image of the figure to be measured obtained by an OPC model building method;

[0036] Figure 2 It is an image of the figure to be measured obtained by an OPC model building method;

[0037] Figure 3 It is an image of the figure to be measured obtained by an OPC model building method;

[0038] Figure 4 It is a flow chart of an embodiment of a method for establishing an OPC model of the present invention;

[0039] Figure 5 It is a flow chart of the step of obtaining the outline of the graphics in the graphic layer in the first embodiment of the method for establishing the OPC model of the present invention;

[0040] Figure 6 is an image of a pattern to be measured obtained by an embodiment of a method for establishing an OPC model of the present invention;

[0041] Figure 7 is an image of a pattern to be measured obtained by an embodiment of a method for establishing an OPC model of the present invention;

[0042] Figure 8 is an image of a pattern to be measured obtained by an embodiment of a method for establishing an OPC model of the present invention;

[0043] Fig. 9 It is a flow chart of the steps of screening the measurement data of the graphic layer in an embodiment of the method for establishing the OPC model of the present invention;

[0044] Fig.10 It is a functional block diagram of an embodiment of an OPC model building device of the present invention. DETAILED DESCRIPTION

[0045] As can be seen from the background technology, the existing method for screening graphic data used to build the OPC model has the problem of low efficiency.

[0046] The data used to build the OPC model is the measurement data obtained from the image obtained by the critical dimensions scanning electron microscope (CD-SEM). The quality of the image obtained by CD-SEM is screened after manual evaluation, so as to screen out the data used for model building (calibration), model verification (verification) or invalid data (VER-OFF). In general, the higher the image quality, the higher the accuracy of the built OPC model.

[0047] The construction or verification of the OPC model is an iterative process. Each time the model is adjusted (Model tuning) to complete the review results, the abnormal (out of spec) data needs to be checked one by one until the results that meet the requirements are obtained.

[0048] In the process of screening the measurement data for building the model, Figure 1 The measurement data corresponding to the image shown can be used to build the OPC model. Figure 2 The measurement data corresponding to the image shown can be directly judged as invalid data and thus directly filtered; Figure 3Whether the measurement data corresponding to the image shown can be used to build the OPC model is determined by the engineers. There will be a considerable degree of subjective judgment, and there is no unified standard to follow. Without a standard, it may lead to misjudgment or omission of data, which will affect the accuracy of the built OPC model. Moreover, the impact on the accuracy of the OPC model may require re-examination of abnormal data. Repeated data review will increase the model building time and affect the efficiency of model building.

[0049] In order to solve the technical problem, the present invention provides a method for establishing an OPC model, comprising:

[0050] A semiconductor structure is formed, wherein the semiconductor structure has a patterned layer; an outline of a pattern in the patterned layer is obtained; and measurement data of the patterned layer is screened according to the obtained outline of the pattern.

[0051] The technical solution of the present invention screens the measurement data of the graphic layer based on the contour of the graphics in the graphic layer, which can effectively shorten the data browsing time, reduce the number of model iterations, and effectively improve the OPC modeling efficiency.

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0053] refer to Figure 4 , showing a flow chart of an embodiment of a method for establishing an OPC model of the present invention.

[0054] The method for establishing the OPC model includes:

[0055] Step S110, forming a semiconductor structure, wherein the semiconductor structure has a patterned layer; Step S120, obtaining an outline of a pattern in the patterned layer; Step S130, screening measurement data of the patterned layer according to the obtained outline of the pattern.

[0056] The technical solution of the OPC model building method embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0057] like Figure 4 As shown, step S110 is first performed to form a semiconductor structure having a patterned layer.

[0058] The OPC model can describe the entire lithography process including the optical system, mask, photoresist, and etching process. Some parameters in the OPC model are calibrated by fitting experimental data, so that the calculated structure of the OPC model is consistent with the experimental results. Step S110, forming a semiconductor structure, wherein the semiconductor structure has a patterned layer, and the patterned layer in the formed semiconductor structure is used to extract the experimental data required to establish the OPC model.

[0059] In some embodiments of the present invention, step S110, the step of forming a semiconductor structure includes: providing a material to be patterned; patterning the material to be patterned to form the patterned layer. For example, the material to be patterned may be a photoresist, and the material to be patterned may be patterned by a photolithography process including exposure and development to form the patterned layer, that is, the patterned layer is a developed photoresist layer.

[0060] In other embodiments, the material to be patterned may also be other materials, and the material to be patterned may be patterned by an etching process to form the patterned layer, that is, the patterned layer is an etched material film layer.

[0061] In some embodiments, step S110, the step of forming a semiconductor structure also includes: forming a test layout, the test layout having a plurality of test patterns; manufacturing a test mask based on the test patterns; and patterning the material to be patterned to form the patterned layer, patterning the material to be patterned through the test mask so that the test patterns on the test mask are transferred to the material to be patterned to form a patterned layer having the test patterns.

[0062] Specifically, the process of patterning the material to be patterned can be carried out by a method suitable for conducting an OPC model building experiment. The patterned layer has a plurality of patterns to be measured. The patterns to be measured in the patterned layer are consistent with the test patterns in the test layout. The consistency between the patterns to be measured and the test patterns means that the plurality of patterns to be measured correspond to the plurality of test patterns one by one.

[0063] It should be noted that the test layout is the graphics designed in the design of experiment (DOE). In order to ensure the accuracy of the established OPC model, it is necessary to improve the coverage of the test graphics in the test layout to the designed layout as much as possible; for complex design layouts, the more diverse the test graphics, the more accurate the established OPC model; but the more diverse the test graphics, the corresponding increase in measurement and modeling time. In order to ensure the coverage of the test graphics, during the design experiment, graphics can be directly extracted from the design layout as the test graphics. Specifically, graphics that are difficult and complex to lithography are extracted from the design layout as key graphics; similar key graphics are classified into one category; representative graphics are extracted from the key graphics of the same category as test graphics to construct the test layout, and then the test mask is made.

[0064] Continue to refer Figure 4 After forming the semiconductor structure, step S120 is then performed to obtain the outline of the pattern in the patterning layer.

[0065] Step S120 is a step of obtaining the outline of the pattern in the patterned layer, that is, obtaining the positions and shapes of multiple patterns to be measured in the patterned layer.

[0066] In some embodiments of the present invention, Figure 5 As shown, step S120, obtaining the outline of the graphics in the graphic layer includes: step S121, obtaining the image of the graphic layer; step S122, extracting the outline of the graphics in the graphic layer according to the graphics of the graphic layer.

[0067] In some embodiments, in step S121, in the step of obtaining the image of the patterned layer, the image of the patterned layer is obtained by a measuring machine. Specifically, in the step of obtaining the image of the patterned layer by a measuring machine, the measuring machine is a scanning electron microscope (SEM). Exemplarily, in the step of obtaining the image of the patterned layer by a measuring machine, the measuring machine is a critical dimension scanning electron microscope (CD-SEM).

[0068] In some embodiments, in step S122, in the step of extracting the contour of the pattern in the pattern layer according to the image of the pattern layer, the contour of the pattern in the pattern layer can be extracted by a feature size scanning electron microscope.

[0069] The information output by the characteristic dimension scanning electron microscope includes: line width (critical dimension, CD), SEM image, scanning line, SEM profile, wherein the SEM profile is the profile of the graphic extracted based on the image of the graphic layer. Therefore, extracting the profile of the graphic in the graphic layer through the characteristic dimension scanning electron microscope means directly using the SEM profile in the information output by the characteristic dimension scanning electron microscope as the profile of the graphic in the graphic layer.

[0070] In other embodiments of the present invention, in the step of obtaining the image of the graphic layer, the image of the graphic layer can also be obtained by a scanning electron microscope; in the step of extracting the contour of the graphics in the graphic layer based on the image of the graphic layer, the contour of the graphics in the graphic layer can also be extracted by image recognition software.

[0071] In some embodiments of the present invention, in step S120, in the step of obtaining the outline of the graphic in the graphic layer, the inner outline and the outer outline of the graphic in the graphic layer are obtained. Specifically, in the step of obtaining the inner outline and the outer outline of the graphic in the graphic layer, the outline of the graphic in the graphic layer can be extracted based on the grayscale of the image of the graphic layer.

[0072] For example, Figures 6 to 8 The images of multiple patterns to be measured in the patterned layer described in the first embodiment of the OPC model establishment method of the present invention are respectively shown. Figure 6 An image of a pattern to be measured for characterizing line-space is shown; Figure 7 An image of a pattern to be measured for characterizing a hole is shown; Figure 8 An image of a pattern to be measured showing the head to head (HTH) spacing.

[0073] Figures 6 to 8 The red solid line in FIG. 1 shows the inner contour and the outer contour obtained in the step of obtaining the contour of the pattern in the patterning layer; Figures 6 to 8 The red thin lines on both sides of the medium and high grayscale areas represent the inner and outer contours of the figure to be measured.

[0074] Continue to refer Figure 4 In some embodiments of the present invention, the establishing method further includes: step S123, performing measurement along a preset measurement direction to obtain measurement data of the graphic layer.

[0075] In some embodiments, in step S123, in the step of measuring along a preset measurement direction to obtain measurement data of the patterned layer, the pattern to be measured in the patterned layer is measured along the preset measurement direction to obtain measurement data of the pattern to be measured.

[0076] Based on the difference of the pattern to be measured, the measurement data may be at least one of a critical dimension (CD), spacing, pitch, length and extension corresponding to the pattern to be measured.

[0077] For example, Figure 6 An image of a pattern to be measured for characterizing line-space is shown, and the measurement data obtained by measuring the pattern to be measured is the line-space; Figure 7 An image of a pattern to be measured for representing a hole is shown, and the measurement data obtained by measuring the pattern to be measured is the aperture r; Figure 8 An image of a pattern to be measured with a head to head spacing (HTH) is shown. The measurement data obtained by measuring the pattern to be measured is the head to head spacing hth.

[0078] Continue to refer Figure 4 The forming method further includes: after obtaining the contour of the pattern in the patterned layer, executing step S130, screening the measurement data of the patterned layer according to the obtained contour of the pattern.

[0079] According to the contour of the obtained figure, the quality of the obtained image is judged, thereby judging whether the measurement data corresponding to the figure is valid, thereby realizing the screening of the measurement data.

[0080] like Fig. 9 As shown, in some embodiments of the present invention, the obtained measurement data is obtained by measuring along the measurement direction; the obtained contour includes the inner contour and the outer contour of the figure; therefore, step S130, the step of screening the measurement data of the graphic layer according to the obtained contour of the figure includes: step S131, obtaining the contour difference in the measurement direction according to the inner contour and the outer contour of the figure in the graphic layer, the contour difference in the measurement direction is the difference between the inner contour and the outer contour in the measurement direction; step S132, judging whether the measurement data of the graphic layer is invalid according to the contour difference in the measurement direction.

[0081] Based on the difference between the inner contour and the outer contour in the measurement direction, i.e., the contour difference, whether the measurement data of the graphic layer is valid is judged to achieve data screening, which can ensure that data screening has a standard to follow and reduce repeated screening caused by data misjudgment.

[0082] For example, in step S131, in the step of obtaining the contour difference in the measurement direction, the contour difference in the measurement direction can be obtained based on the number of pixels between the inner contour and the outer contour in the measurement direction in the contour of the obtained figure, combined with the resolution of the image of the graphic layer obtained.

[0083] Specifically, Figures 6 to 8 In the illustrated embodiment, in the step of obtaining the image of the patterned layer, the image of the patterned layer is obtained at a magnification of 200K; the resolution of the obtained image of the patterned layer is 512×512, so the size of one pixel is approximately 1.3nm×1.3nm.

[0084] In some embodiments, in step S132, in the step of determining whether the measurement data of the graphic layer is invalid, it is determined whether the measurement data of the graphic layer is invalid based on the ratio of the contour difference in the measurement direction to the measurement data in the measurement direction.

[0085] Specifically, in the step of determining whether the measurement data of the graphic layer is invalid, the relative sizes of the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction and a preset first threshold are compared: when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is less than or equal to the first threshold, the measurement data of the graphic layer is determined to be valid; when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is greater than the first threshold, the measurement data of the graphic layer is determined to be invalid.

[0086] In some embodiments, the size of the first threshold is related to the dimension of the graphic. In step S132, in the step of determining whether the measurement data of the graphic layer is invalid, the measurement data of the graphic layer is determined to be invalid based on the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction, combined with the dimension of the graphic in the graphic layer.

[0087] Specifically, for a one-dimensional pattern to be measured, the first threshold is 20%; for a two-dimensional pattern to be measured, the first threshold is 40%.

[0088] For example, Figure 6 The measured figure used to characterize the line-space is a one-dimensional figure. When the ratio of the contour difference d1 to the line-space spacing is less than or equal to 20%, the line-space measurement value is valid data. When the ratio of the contour difference d1 to the line-space spacing is greater than 20%, the line-space measurement value is invalid data.

[0089] Figure 8The figure to be measured for the head to head (HTH) spacing is a two-dimensional figure. When the ratio of the contour difference d2 to the line end spacing hth is less than or equal to 40%, the line end spacing measurement value is valid data. When the ratio of the contour difference d2 to the line end spacing hth is greater than 40%, the line end spacing measurement value is invalid data.

[0090] like Fig. 9 As shown, in some embodiments, when the measurement data of the graphic layer is judged to be valid data, step S130, the step of screening the measurement data of the graphic layer according to the contour of the obtained graphic also includes: step S133, judging whether the measurement data of the graphic layer is modeling data or verification data according to the contour difference in the measurement direction.

[0091] The modeling data is used to establish an OPC model, and the verification data is used to verify an existing OPC model.

[0092] Specifically, in the step of determining whether the measurement data of the graphic layer is modeling data or verification data, the relative sizes of the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction and a preset second threshold are compared: when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is less than the second threshold, the measurement data of the graphic layer is determined to be modeling data; when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is greater than or equal to the second threshold, the measurement data of the graphic layer is determined to be verification data.

[0093] In some embodiments, the size of the second threshold is also related to the dimension of the graphics. In step S132, in the step of determining whether the measurement data of the graphic layer is invalid, based on the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction, combined with the dimension of the graphics in the graphic layer, it is determined whether the measurement data of the graphic layer is modeling data or verification data.

[0094] Specifically, for a one-dimensional pattern to be measured, the second threshold is 10%; for a two-dimensional pattern to be measured, the second threshold is 20%.

[0095] For example, Figure 6 The figure to be measured shown as used to characterize the line-space is a one-dimensional figure. When the ratio of the contour difference d1 to the line-space spacing is less than 10%, the line-space measurement value is modeling data and can be used to establish the OPC model; when the ratio of the contour difference d1 to the line-space spacing is greater than or equal to 10%, the line-space measurement value is verification data and can be used to verify the OPC model.

[0096] Figure 8The figure to be measured for the head to head (HTH) spacing shown is a two-dimensional figure. When the ratio of the contour difference d2 to the head to head spacing hth is less than 20%, the measured value of the head to head spacing is modeling data and can be used to establish an OPC model. When the ratio of the contour difference d2 to the head to head spacing hth is greater than or equal to 20%, the measured value of the head to head spacing is verification data and can be used to verify the OPC model.

[0097] Continue to refer Figure 4 In some embodiments of the present invention, the establishment method further includes: step S140, performing model operation according to the filtered measurement data, wherein the model operation includes: one of establishing an OPC model and verifying the OPC model.

[0098] The filtered measurement data are all valid data, which can be used for model operation, that is, they can be used to calibrate the OPC model and verify the OPC model. Based on the outline of the graphics in the graphical layer, the measurement data is filtered, which can effectively shorten the data browsing time, reduce the number of model iterations, and effectively improve the OPC modeling efficiency. Among them, establishing the OPC model includes creating a new OPC model and modifying the OPC model.

[0099] In some embodiments, step S140, the step of performing model operations based on the filtered measurement data includes: establishing an OPC model based on the modeling data, that is, the model operation performed based on the modeling data is to establish the OPC model; verifying the OPC model based on the verification data, that is, the model operation performed based on the modeling data is to verify the OPC model.

[0100] It should be noted that if Figure 4 In some of the embodiments shown, the establishment method further includes: after filtering the measurement data of the graphic layer, before performing model operation based on the filtered measurement data, executing step S150 to review the filtered measurement data.

[0101] After screening and obtaining valid data, the valid data obtained is reviewed again, which can further eliminate abnormal data to improve the accuracy of model operations, effectively reduce the number of iterations, and improve modeling efficiency.

[0102] Correspondingly, the present invention also provides an optical proximity correction method.

[0103] The optical proximity correction method comprises: obtaining a design layout; establishing an OPC model, wherein the OPC model is established by the establishment method of the present invention; and using the OPC model to correct the design layout to obtain a tape-out layout.

[0104] Specifically, the step of obtaining the design layout includes: obtaining a GDS (Geometry Summary Data) file of the design layout. The GDS file is used to define the three-dimensional structure and electrical characteristics of the chip, and the GDS file contains geometric data related to the chip structure, shape and hierarchical structure.

[0105] In the step of establishing the OPC model, the OPC model is established by the establishment method of the present invention. The specific technical scheme of the step of establishing the OPC model can refer to the embodiment of the above-mentioned method for establishing the OPC model, and the present invention will not repeat it here.

[0106] Afterwards, the design layout is modified based on the OPC model to obtain a tape-out layout.

[0107] Correspondingly, the present invention also provides a device for establishing an OPC model.

[0108] refer to Fig.10 , showing a functional block diagram of an embodiment of an OPC model building device of the present invention.

[0109] The OPC model establishment device comprises:

[0110] A process unit 210, wherein the process unit 210 is suitable for forming a semiconductor structure, wherein the semiconductor structure has a patterned layer;

[0111] a measuring unit 220, the measuring unit 220 being adapted to obtain the contour of the pattern in the patterning layer;

[0112] The screening unit 230 is adapted to screen the measurement data of the patterned layer according to the contour of the obtained pattern.

[0113] In some embodiments of the present invention, the OPC model building device is suitable for executing the steps of the OPC model building method of the present invention. The specific technical solution of the OPC model building device can refer to the embodiment of the aforementioned OPC model building method.

[0114] The technical solution of the OPC model building device embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0115] The process unit 210 is used to form a semiconductor structure having a patterned layer.

[0116] The OPC model can describe the entire photolithography process including the optical system, mask, photoresist, and etching process. Some parameters in the OPC model are calibrated by fitting experimental data, so that the calculated structure of the OPC model is consistent with the experimental results; the graphic layer in the semiconductor structure formed by the process unit 210 is used to extract the experimental data required to establish the OPC model.

[0117] In some embodiments of the present invention, the process unit 210 may be a semiconductor manufacturing system for the entire photolithography process including an optical system, a mask, a photoresist, and an etching process. In other embodiments of the present invention, the process unit may also be a control device connected to the semiconductor manufacturing system.

[0118] In the semiconductor structure, the patterned layer can be a photoresist patterned by a photolithography process including exposure and development, that is, the patterned layer is a developed photoresist layer. In other embodiments, the patterned layer can also be a material film layer processed by an etching process, that is, the patterned layer is an etched material film layer.

[0119] The patterning of the patterning layer is performed based on a test layout. The patterning layer has a pattern to be measured. The pattern to be measured is consistent with a test pattern in the test layout, that is, the pattern to be measured corresponds to the test pattern in the test layout one by one.

[0120] It should be noted that the test layout is the graphics designed in the design of experiment (DOE). In order to ensure the accuracy of the established OPC model, it is necessary to improve the coverage of the test graphics in the test layout to the designed layout as much as possible; for complex design layouts, the more diverse the test graphics, the more accurate the established OPC model; but the more diverse the test graphics, the corresponding increase in measurement and modeling time. In order to ensure the coverage of the test graphics, during the design experiment, graphics can be directly extracted from the design layout as the test graphics. Specifically, graphics that are difficult and complex to lithography are extracted from the design layout as key graphics; similar key graphics are classified into one category; representative graphics are extracted from the key graphics of the same category as test graphics to construct the test layout, and then the test mask is made.

[0121] The measurement unit 220 is used to obtain the outline of the pattern in the patterning layer.

[0122] The measuring unit 220 obtains the position and shape of each pattern to be measured in the patterning layer.

[0123] like Fig.10As shown, in some embodiments of the present invention, the measuring unit 220 includes: an imager 221, wherein the imager 221 is suitable for obtaining an image of the graphic layer; and an extractor 222, wherein the extractor 222 is suitable for extracting the contour of the graphic in the graphic layer according to the graphic of the graphic layer.

[0124] In some embodiments, at least the imager 221 is a measuring machine. For example, the measuring machine may be a scanning electron microscope (SEM), such as a critical dimension scanning electron microscope (CD-SEM).

[0125] In some exemplary embodiments, the extractor 222 is also a feature dimension scanning electron microscope, that is, the measurement unit 320 may include: a feature dimension scanning electron microscope. The information output by the feature dimension scanning electron microscope includes: line width (critical dimension, CD), SEM image, scanning line, SEM profile, wherein the SEM profile is the profile of the graphic extracted from the image of the graphic layer, so extracting the profile of the graphic in the graphic layer through the feature dimension scanning electron microscope is to directly use the SEM profile in the information output by the feature dimension scanning electron microscope as the profile of the graphic in the graphic layer.

[0126] In other embodiments of the present invention, only the imager in the measurement unit is a scanning electron microscope; the extractor may also be other software or hardware that can realize image recognition to extract the outline of the graphics in the graphic layer.

[0127] In some embodiments of the present invention, the measuring unit 220 obtains the inner contour and the outer contour of the pattern in the pattern layer. Specifically, the measuring unit 220 extracts the contour of the pattern in the pattern layer based on the grayscale of the image of the pattern layer.

[0128] For example, Figures 6 to 8 The images of multiple patterns to be measured in the patterned layer obtained by the measuring unit of an embodiment of the OPC model building device of the present invention are respectively shown. Figure 6 An image of a pattern to be measured for characterizing line-space is shown; Figure 7 An image of a pattern to be measured for characterizing a hole is shown; Figure 8 An image of a pattern to be measured showing the head to head (HTH) spacing.

[0129] Figures 6 to 8The red solid line in FIG. 1 shows the inner contour and outer contour obtained by the measuring unit of the OPC model building device embodiment; Figures 6 to 8 The red thin lines on both sides of the medium and high grayscale areas represent the inner and outer contours of the figure to be measured.

[0130] In some embodiments of the present invention, the measuring unit 220 is further adapted to perform measurement along a preset measuring direction to obtain measurement data of the patterned layer.

[0131] In some embodiments, the measurement unit 220 measures the pattern to be measured in the patterned layer along a preset measurement direction to obtain measurement data of the pattern to be measured. Specifically, based on the difference of the pattern to be measured, the measurement data may be at least one of the critical dimension (CD), spacing, pitch, length, and extension corresponding to the pattern to be measured.

[0132] For example, Figure 6 An image of a pattern to be measured for characterizing line-space is shown, and the measurement data obtained by measuring the pattern to be measured is the line-space; Figure 7 An image of a pattern to be measured for representing a hole is shown, and the measurement data obtained by measuring the pattern to be measured is the aperture r; Figure 8 An image of a pattern to be measured with a head to head spacing (HTH) is shown. The measurement data obtained by measuring the pattern to be measured is the head to head spacing hth.

[0133] Continue to refer Fig.10 The establishing device further includes: a screening unit 230, wherein the screening unit 230 screens the measurement data of the graphic layer according to the contour of the obtained graphic.

[0134] The screening unit 230 is used to determine the quality of the obtained image, thereby determining whether the measurement data corresponding to the image is valid, thereby implementing screening of the measurement data.

[0135] In some embodiments of the present invention, the measurement data obtained by the measurement unit 220 is obtained by measuring along the measurement direction; the obtained contour includes the inner contour and the outer contour of the graphic; therefore, the screening unit 230 includes: an interpolator 231, the interpolator 231 is suitable for obtaining the contour difference in the measurement direction according to the inner contour and the outer contour of the graphic in the graphic layer, and the contour difference in the measurement direction is the difference between the inner contour and the outer contour in the measurement direction; a judger 232, the judger 232 is suitable for judging whether the measurement data of the graphic layer is invalid according to the contour difference in the measurement direction.

[0136] Based on the difference between the inner contour and the outer contour in the measurement direction, i.e., the contour difference, whether the measurement data of the graphic layer is valid is judged to achieve data screening, which can ensure that data screening has a standard to follow and reduce repeated screening caused by data misjudgment.

[0137] For example, the differentiator 231 obtains the contour difference in the measurement direction according to the number of pixels between the inner contour and the outer contour in the obtained contour of the graphic in the measurement direction, combined with the resolution of the obtained image of the graphic layer.

[0138] Specifically, Figures 6 to 8 In the illustrated embodiment, the measurement unit 220 obtains the image of the patterned layer at a magnification of 200K; the resolution of the obtained image of the patterned layer is 512×512, so the size of one pixel is approximately 1.3 nm×1.3 nm.

[0139] In some embodiments, the determiner 232 determines whether the measurement data of the patterned layer is invalid according to a ratio of the contour difference in the measurement direction to the measurement data in the measurement direction.

[0140] Specifically, a first threshold is pre-stored in the judgement device 232, and the judgement device 232 compares the relative size of the ratio of the contour difference value in the measurement direction and the measurement data in the measurement direction and the first threshold: when the ratio of the contour difference value in the measurement direction and the measurement data in the measurement direction is less than or equal to the first threshold, the judgement device 232 judges that the measurement data of the graphic layer is valid; when the ratio of the contour difference value in the measurement direction and the measurement data in the measurement direction is greater than the first threshold, the judgement device 232 judges that the measurement data of the graphic layer is invalid.

[0141] In some embodiments, the size of the first threshold is related to the dimension of the graphic. Specifically, for a one-dimensional graphic to be measured, the first threshold is 20%; for a two-dimensional graphic to be measured, the first threshold is 40%.

[0142] For example, Figure 6 The figure to be measured shown as being used to characterize line-space is a one-dimensional figure. When the ratio of the contour difference d1 to the line-space spacing is less than or equal to 20%, the judgement device 232 judges that the line-space measurement value is valid data. When the ratio of the contour difference d1 to the line-space spacing is greater than 20%, the judgement device 232 judges that the line-space measurement value is invalid data.

[0143] Figure 8 The figure to be measured for the head to head (HTH) spacing is a two-dimensional figure. When the ratio of the contour difference d2 to the line end spacing hth is less than or equal to 40%, the judgement device 232 judges that the line end spacing measurement value is valid data. When the ratio of the contour difference d2 to the line end spacing hth is greater than 40%, the judgement device 232 judges that the line end spacing measurement value is invalid data.

[0144] like Fig.10 In some of the embodiments shown, the screening unit 230 also includes: a classifier 233. When the judger 232 judges that the measurement data of the graphic layer is valid data, the classifier 233 judges whether the measurement data of the graphic layer is modeling data or verification data based on the contour difference in the measurement direction.

[0145] The modeling data is used to establish an OPC model, and the verification data is used to verify an existing OPC model.

[0146] Specifically, a second threshold is preset in the classifier 233, and the classifier 233 compares the relative size of the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction with the preset second threshold: when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is less than the second threshold, the classifier 233 determines that the measurement data of the graphic layer is modeling data; when the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction is greater than or equal to the second threshold, the classifier 233 determines that the measurement data of the graphic layer is verification data.

[0147] In some embodiments, the size of the second threshold is also related to the dimension of the graphic. The classifier 233 determines whether the measurement data of the graphic layer is modeling data or verification data based on the ratio of the contour difference in the measurement direction and the measurement data in the measurement direction, combined with the dimension of the graphic in the graphic layer.

[0148] Specifically, for a one-dimensional pattern to be measured, the second threshold is 20%; for a two-dimensional pattern to be measured, the second threshold is 40%.

[0149] For example, Figure 6 The figure to be measured shown as being used to characterize line-space is a one-dimensional figure. When the ratio of the contour difference d1 to the line-space spacing is less than 10%, the classifier 233 determines that the line-space measurement value is modeling data; when the ratio of the contour difference d1 to the line-space spacing is greater than or equal to 10%, the classifier 233 determines that the line-space measurement value is verification data.

[0150] Figure 8 The figure to be measured for the head to head (HTH) spacing is a two-dimensional figure. When the ratio of the contour difference d2 to the head to head spacing hth is less than 20%, the classifier 233 determines that the measured value of the head to head spacing is modeling data; when the ratio of the contour difference d2 to the head to head spacing hth is greater than or equal to 20%, the classifier 233 determines that the measured value of the head to head spacing is verification data.

[0151] Continue to refer Fig.10 In some embodiments of the present invention, the establishing device further includes: a modeling unit 240, wherein the modeling unit 240 is suitable for performing model operations based on the screened measurement data, wherein the model operations include: one of establishing an OPC model and verifying an OPC model.

[0152] The filtered measurement data are all valid data. The modeling unit 240 performs model operations based on the filtered measurement data, that is, it can be used to calibrate and verify the OPC model. Based on the outline of the graphics in the graphical layer, the measurement data is filtered, which can effectively shorten the data browsing time, reduce the number of model iterations, and effectively improve the OPC modeling efficiency.

[0153] In some embodiments, when the judger 232 of the screening unit 230 judges that the measurement data of the graphic layer is valid data, the classifier 233 judges whether the measurement data of the graphic layer is modeling data or verification data; the modeling unit 240 includes: a modeler, the modeler is suitable for establishing an OPC model according to the modeling data, that is, according to the modeling data, the modeler can execute the establishment of the OPC model; a verifier, the verifier is suitable for verifying the OPC model according to the verification data, that is, according to the modeling data, the verifier can execute the model operation of verifying the OPC model.

[0154] It should be noted that if Fig.10 In some of the embodiments shown, the establishing device further includes: a review unit 250, and the review unit 250 is suitable for reviewing the filtered measurement data.

[0155] After the screening unit 230 obtains valid data, the review unit 250 reviews the obtained valid data again, and can further eliminate abnormal data to improve the accuracy of the model operation performed by the modeling unit 240, which can effectively reduce the number of iterations and improve modeling efficiency.

[0156] Correspondingly, the present invention also provides an optical proximity correction device.

[0157] like Fig.10 As shown, the optical proximity correction device includes:

[0158] Establishing means 310, the establishment

[0159] The establishment device 310 is suitable for establishing an OPC model, and the establishment device is as described in any one of claims 12 to 16; the acquisition device 320, the acquisition device 320 is suitable for acquiring a design layout; the correction device 330, the correction device 330 is suitable for using the OPC model to correct the design layout to obtain a wafer layout.

[0160] The establishing device 310 is the establishing device of the present invention. The specific technical solution of the establishing device 310 can refer to the embodiment of the establishing device of the aforementioned OPC model, and the present invention will not repeat it here.

[0161] The acquisition device 320 obtains the GDS (Geometry Summary Data) file of the design layout. The GDS file is used to define the three-dimensional structure and electrical characteristics of the chip, and the GDS file contains geometric data related to the chip structure, shape and hierarchical structure.

[0162] The correction device 330 corrects the design layout based on the OPC model to obtain a tape-out layout.

[0163] In addition, the present invention also provides a readable storage medium on which a computer program is stored. The computer program is executed by a processor to implement the steps of the OPC model establishment method of the present invention.

[0164] The computer program stored in the readable storage medium is executed by the processor to implement the steps of the OPC model establishment method of the present invention. The specific technical solution of the readable storage medium can refer to the embodiment of the above-mentioned OPC model establishment method, and the present invention will not repeat it here.

[0165] In summary, based on the obtained contours of the graphics in the graphic layer, the measurement data of the graphic layer is screened, which can effectively shorten the data browsing time, reduce the number of model iterations, and effectively improve the OPC modeling efficiency.

[0166] Moreover, based on the difference between the inner contour and the outer contour in the measuring direction, whether the measuring data of the graphic layer is valid is judged to achieve data screening, which can ensure that the data screening has a standard to follow and can reduce repeated screening caused by data misjudgment.

[0167] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for establishing an OPC model, characterized in that: include: forming a semiconductor structure, the semiconductor structure having a patterned layer; Obtaining the outline of the graphics in the graphic layer; The measurement data of the patterned layer is screened according to the contour of the obtained pattern.

2. The method of establishing as claimed in claim 1, characterized in that: Also includes: Model operation is performed according to the screened measurement data, wherein the model operation includes: one of establishing an OPC model and verifying the OPC model.

3. The establishment method according to claim 2, characterized in that: Also includes: After the measurement data of the graphic layer is screened, the screened measurement data is reviewed before the model operation is performed based on the screened measurement data.

4. The establishment method according to claim 1, characterized in that: Obtaining the outline of the graphics in the graphic layer includes: obtaining an image of the patterned layer; According to the graphics of the graphic layer, the outline of the graphics in the graphic layer is extracted.

5. The establishment method according to claim 4, characterized in that: In the step of obtaining the image of the patterned layer, the image of the patterned layer is obtained by a measuring machine.

6. The establishment method according to claim 5, characterized in that: In the step of obtaining the image of the patterned layer by using a measuring machine, the measuring machine is a scanning electron microscope.

7. The method of establishing as claimed in claim 6, characterized in that: In the step of obtaining the image of the patterned layer by using a measuring machine, the measuring machine is a feature size scanning electron microscope.

8. The establishment method according to claim 1, characterized in that: Also includes: Performing measurement along a preset measurement direction to obtain measurement data of the patterned layer; In the step of obtaining the outline of the pattern in the patterned layer, an inner outline and an outer outline of the pattern in the patterned layer are obtained; The step of screening the measurement data of the patterned layer according to the contour of the obtained pattern comprises: According to the inner contour and the outer contour of the pattern in the patterned layer, a contour difference in the measuring direction is obtained, wherein the contour difference in the measuring direction is the difference between the inner contour and the outer contour in the measuring direction; Whether the measurement data of the patterned layer is invalid is determined according to the contour difference in the measurement direction.

9. The method of establishing as claimed in claim 8, characterized in that: In the step of determining whether the measurement data of the patterned layer is invalid, determining whether the measurement data of the patterned layer is invalid is performed based on a ratio of a contour difference in the measurement direction to the measurement data in the measurement direction.

10. The establishment method according to claim 9, characterized in that: In the step of determining whether the measurement data of the graphic layer is invalid, the measurement data of the graphic layer is determined to be invalid based on the ratio of the contour difference in the measurement direction to the measurement data in the measurement direction and the dimension of the graphic in the graphic layer.

11. The establishment method according to claim 8, characterized in that: When the measurement data of the graphic layer is determined to be valid data, the step of screening the measurement data of the graphic layer according to the contour of the obtained graphic further includes: determining whether the measurement data of the graphic layer is modeling data or verification data according to the contour difference in the measurement direction.

12. The establishment method according to claim 11, characterized in that: The step of performing model operation according to the screened measurement data includes: establishing an OPC model according to the modeling data; and verifying the OPC model according to the verification data.

13. An optical proximity correction method, characterized in that: include: Get the design layout; Establishing an OPC model, wherein the OPC model is established by the establishment method described in any one of claims 1 to claim 12; The OPC model is used to modify the design layout to obtain a tape-out layout.

14. An OPC model establishment device, characterized in that: include: a process unit, the process unit being suitable for forming a semiconductor structure, the semiconductor structure having a patterned layer; a measurement unit, the measurement unit being adapted to obtain the contour of the pattern in the patterning layer; A screening unit is adapted to screen the measurement data of the patterned layer according to the contour of the obtained pattern.

15. The establishment device according to claim 14, characterized in that Also includes: A modeling unit, wherein the modeling unit is adapted to perform model operations according to the screened measurement data, wherein the model operations include: establishing an OPC model and verifying the OPC model.

16. The establishment device according to claim 14, characterized in that Also includes: An audit unit, wherein the audit unit is suitable for auditing the screened measurement data.

17. The establishment device according to claim 14, characterized in that The measuring unit comprises: an imager adapted to obtain an image of the patterned layer; An extractor is adapted to extract the contour of the pattern in the pattern layer according to the pattern in the pattern layer.

18. The establishment device according to claim 14, characterized in that The measuring unit is also suitable for measuring along a preset measuring direction to obtain the measurement data of the patterned layer; The measuring unit is suitable for obtaining the inner contour and the outer contour of the pattern in the patterning layer; The screening unit comprises: A differentiator, the differentiator being adapted to obtain a contour difference in the measuring direction according to an inner contour and an outer contour of the pattern in the patterned layer, wherein the contour difference in the measuring direction is a difference between the inner contour and the outer contour in the measuring direction; A judger is adapted to judge whether the measurement data of the patterned layer is invalid according to the contour difference in the measurement direction.

19. The establishment device according to claim 18, characterized in that The screening unit further includes: a classifier, and when the judger judges that the measurement data of the graphic layer is valid data, the classifier judges whether the measurement data of the graphic layer is modeling data or verification data according to the contour difference in the measurement direction.

20. An optical proximity correction device, characterized in that: include: Establishment means, the establishment means being adapted to establish an OPC model, the establishment means being as claimed in any one of claims 14 to 19; An acquisition device, wherein the acquisition device is suitable for acquiring a design layout; The correction device is suitable for using the OPC model to correct the design layout to obtain a tape-out layout.

21. A storage medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the steps of the method according to any one of claims 1 to 12.

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