Method, electronic device and computer-readable storage medium for optical proximity correction

Abstract

Embodiments of the present disclosure relate to a method, an electronic device, and a computer-readable storage medium for optical proximity correction. The method includes: determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on an anchor point and the optical signal portion; determining the ratio of the optical signal portion to the signal portion of the OPC model; and determining the model used in the correction cycle to correct the layout based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle. The technical solution of the present disclosure can save computing resources and significantly reduce the time for model simulation and correction.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to integrated circuits, and more particularly, to methods, electronic devices, and computer-readable storage media for optical proximity correction. Background Art

[0002] Computational lithography is an important driving force for the continued development of graphic miniaturization technology since the 1990s. Computational lithography aims to break through the hardware limitations of the minimum exposure size by improving software technologies such as resolution while keeping the existing hardware environment such as lithography machines unchanged, which has greatly promoted the development of advanced semiconductor processes.

[0003] The production of integrated circuit chips at advanced process nodes usually relies on graphic technology. The core of graphic technology is optical proximity correction (OPC), and OPC is even often used to refer to all computational lithography technologies. When OPC technology is used to modify the chip design layout, it often requires thousands or even tens of thousands of CPU core computing resources (based on different technology nodes, advanced technology nodes will require more computing resources), so the algorithm optimization of the OPC correction program is the key to improving efficiency and reducing costs. Summary of the invention

[0004] According to example embodiments of the present disclosure, a scheme for optical proximity correction is provided to at least partially overcome the above or other potential drawbacks.

[0005] According to one aspect of the present disclosure, a method for optical proximity correction is provided. The method includes: determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on an anchor point and the optical signal portion; determining a ratio of the optical signal portion to a signal portion of the OPC model; and determining a model used in the correction cycle to correct a layout based on a numerical relationship between the ratio and an attenuation coefficient in a correction cycle.

[0006] The solutions of some embodiments of the present disclosure adopt a rough-to-precise approach for full-layout OPC correction of advanced processes, first using a fast model to achieve preliminary results, and then using a precise model to correct them. Under the condition of the same final correction accuracy, the model simulation time is reduced by about 60%, thereby reducing the OPC correction time by 45-50%.

[0007] In a second aspect of the present disclosure, an electronic device is provided. The electronic device includes a processor; and a memory coupled to the processor, the memory having instructions stored therein, and when the instructions are executed by the processor, the device performs an action, the action including determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on an anchor point and the optical signal portion; determining a ratio of the optical signal portion to a signal portion of the OPC model; and determining a model used in the correction cycle to correct the layout based on a numerical relationship between the ratio and an attenuation coefficient in a correction cycle.

[0008] In some embodiments, generating a simplified model of the OPC model based on the anchor point and the optical signal part includes: using the optical signal part as the main signal part of the simplified model; generating a simulation signal of the layout from the optical signal part; determining the critical size of the graphics in the layout based on the anchor point; and determining the signal threshold of the simplified model based on the critical size and the simulation signal.

[0009] In some embodiments, generating a simulation signal of the layout from the optical signal portion includes: generating the simulation signal based on the optical signal in the optical signal portion and the layout.

[0010] In some embodiments, the simulation signal is generated using the following formula: new_simulation_signal =optical @ layout; wherein new_simulation_signal is a simulation signal generated by a simplified model, optical represents an optical signal in an OPC model, @ represents a convolution symbol, and layout represents a layout.

[0011] In some embodiments, determining the critical dimension of the pattern based on the anchor point includes: in response to a simulated line width of the simplified model at the anchor point being consistent with a corresponding measured line width on the wafer, using the simulated line width as the critical dimension.

[0012] In some embodiments, determining the ratio of the optical signal portion to the signal portion of the OPC model includes: determining the integral of the optical signal in the OPC model; respectively determining the product of the integral of each kernel function signal of the OPC model and the corresponding coefficient; determining the sum of the sum of each product and the integral; and determining the ratio of the integral of the optical signal to the sum as a ratio.

[0013] In some embodiments, determining the ratio of the optical signal portion to the signal portion of the OPC model includes calculating the ratio using the following formula:

[0014] ; where k represents the ratio, optical represents the optical signal in the OPC model, kernelj represents the signal of the jth kernel function, and C jRepresents the coefficient of the signal of the j-th kernel function, m is a positive integer, representing the m-th kernel function.

[0015] In some embodiments, responsive to the ratio being not greater than the attenuation factor in the correction cycle, correcting the layout using the OPC model in the correction cycle includes correcting the layout using the OPC model in a last predetermined number of correction cycles.

[0016] In some embodiments, the predetermined number is greater than or equal to three.

[0017] In some embodiments, in each calibration cycle, the attenuation coefficient in each calibration cycle is less than or equal to the attenuation coefficient in the calibration cycle immediately following the calibration cycle.

[0018] In a third aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the method according to the first aspect of the present disclosure is implemented.

[0019] It will be understood from the following description that the technical solution of the present disclosure can save computing resources and significantly reduce the time for model simulation and correction.

[0020] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram showing an example environment in which embodiments of the present disclosure can be implemented;

[0022] Figure 2 A flow chart showing a method for optical proximity correction according to some embodiments of the present disclosure is shown;

[0023] Figure 3 A schematic diagram of a kernel function according to some embodiments of the present disclosure is shown;

[0024] Figure 4 A schematic diagram showing signals with different gradients according to some embodiments of the present disclosure;

[0025] Figure 5 A schematic diagram showing a method for determining a signal threshold of a simplified model according to some embodiments of the present disclosure;

[0026] Figure 6 A schematic diagram showing a method for determining a simulation signal according to some embodiments of the present disclosure is shown;

[0027] Figure 7A block diagram of a computing device capable of implementing various embodiments of the present disclosure is shown.

[0028] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0029] The principles of the present disclosure will be described below with reference to the various exemplary embodiments shown in the accompanying drawings. It should be understood that the description of these embodiments is only to enable those skilled in the art to better understand and further implement the present disclosure, and is not intended to limit the scope of the present disclosure in any way. It should be noted that similar or identical reference numerals may be used in the figures where feasible, and similar or identical reference numerals may represent similar or identical functions. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods described herein may be adopted without departing from the principles of the present invention described herein.

[0030] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects.

[0031] As mentioned earlier, during the running of the OPC correction (or correction) program, the layout will be split, and the specific graphics (polygon) will be split into graphic segments (polygon segments), and the signal sampling point will be selected on the graphic segment, and then the OPC model simulation will be used to obtain the signal of this sampling point, so as to determine how to move the corresponding graphic segment in the subsequent correction. In actual operation, OPC correction is usually not done in one step, but in multiple cycles. That is to say, for each corresponding graphic segment, a simulation will be performed in each round of correction cycle. Therefore, during the running process of the OPC correction program, most of the time consumed comes from model simulation (depending on the different OPC correction programs, the proportion of model simulation is about 75~95%).

[0032] In advanced technology, due to the insufficient signal gradient of the model, or the low signal gradient (because the signal gradient of the advanced technology itself is much smaller than the signal gradient of the mature technology), the convergence of the OPC correction process will be very slow. Therefore, the OPC correction corresponding to the advanced technology often requires more than ten times, or even dozens of times or more cycles, which results in a lot of time consumption.

[0033] In view of this, the present disclosure provides an improved solution.

[0034] Embodiments of the present disclosure provide an improved method for optical proximity correction. The method includes: determining an optical signal portion in an optical proximity correction (OPC) model, wherein the main component of the OPC model is the optical signal portion. A simplified model of the OPC model is generated based on an anchor point and the optical signal portion. Determine the ratio of the optical signal portion in the signal portion of the OPC model. Based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle, determine the model used in the correction cycle to correct the layout. The embodiments of the present disclosure determine to use different models for OPC correction at different stages by comparing the ratio with the attenuation coefficient, which can save computing resources and significantly reduce the time for model simulation and correction.

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0036] Figure 1 1 is a schematic diagram of an example environment 100 in which embodiments according to the present disclosure can be implemented. Figure 1 As shown, the example environment 100 includes a computing device 110 and a client 120 .

[0037] In some embodiments, the computing device 110 may interact with the client 120. For example, the computing device 110 may receive an input message from the client 120 and output a feedback message to the client 120. In some embodiments, the input message from the client 120 may be design layout data or data of an OPC model, etc. The computing device 110 may perform corresponding mathematical operations on the design layout data or data of an OPC model, etc., and output the corresponding operation results to the client 120.

[0038] In some embodiments, computing device 110 may include, but is not limited to, a personal computer, a server computer, a handheld or laptop device, a mobile device (such as a mobile phone, a personal digital assistant (PDA), a media player, etc.), consumer electronics, a minicomputer, a mainframe computer, cloud computing resources, etc.

[0039] It should be understood that the structure and function of the example environment 100 are described for exemplary purposes only and are not intended to limit the scope of the subject matter described herein. The subject matter described herein can be implemented in different structures and / or functions. The environment is merely illustrative and is not intended to limit the application environment of the embodiments of the present disclosure.

[0040] In order to explain the principle of the present disclosure more clearly, the following will refer to Figure 2 Let's describe it in more detail.

[0041] Figure 2A flow chart of a calibration method 200 for an optical proximity correction model according to some embodiments of the present disclosure is shown.

[0042] At block 202, an optical signal portion in an optical proximity correction (OPC) model is determined.

[0043] The structure of the OPC model mainly includes the optical part (or optical signal part) and other parts. Specifically, when building models, the existing OPC model usually adds some additional fitting items to modulate the signal in addition to the optical part, so as to obtain more accurate simulation prediction results. The other parts are mainly the kernel signal part. Usually, the optical part in the OPC model will occupy most of the signal sources, while other signals from different kernel functions are supplementary.

[0044] The kernel function can be a basic function used in the lithography model to simulate the lithography behavior. In some embodiments, the kernel function can be a two-dimensional function set in the OPC model. The kernel function will be stored as a two-dimensional array inside the computer. The two-dimensional function can be used to provide a signal for fitting. In some embodiments, the kernel function can be used to approximate at least one of the following effects in lithography: load effect; chemical amplification effect; and photoresist stress effect. In a broad sense, the simulated light signal is also a kernel function, so the OPC model can be regarded as consisting of multiple kernel functions. For ease of description, in the embodiments of the present disclosure, unless otherwise specified, the kernel function mentioned is distinguished from the light signal. There is no limit on the number of kernel functions in principle, but more kernel functions will lead to longer simulation time, which in turn affects the overall time required for OPC correction. Therefore, under the premise that the obtained model is sufficiently accurate, the number of kernel functions used is usually minimized.

[0045] The kernel function can be expressed and understood as z = f(x, y). Figure 3 Give a description. Figure 3 FIG. 4 shows a schematic diagram of a kernel function according to some embodiments of the present disclosure. Figure 3 As shown, the intuitive form of the kernel function is shown. As shown in the figure, the kernel function is represented by z = f(x, y), where x and y represent coordinates, such as position coordinates within the model, and z represents the value of the kernel function. Since these two-dimensional functions and the design layout will be convolved when the signal is subsequently calculated, such two-dimensional functions are often called "kernel functions" by analogy with the convolution kernel in the integral transform.

[0046] Continue back Figure 2 This is described at block 202 of FIG.

[0047] The OPC model can generate a simulation signal. The simulation signal can be related to the following values: the product of the signal of the kernel function of the OPC model and the corresponding coefficient, and the optical signal of the pattern in the layout. Specifically, the simulation signal can be determined by the following formula:

[0048]

[0049] Among them, simulation_signal represents the simulation signal, optical represents the optical signal, and Kernel m represents the signal from the mth kernel function, C1, C2, … Cm represents the coefficient of the signal of the kernel function, m is a positive integer, @ represents the convolution symbol, layout Represents the layout, is the product symbol.

[0050] It should be understood that the above formula for calculating the simulation signal value schematically illustrates a method for determining the simulation signal value, and the embodiments of the present disclosure are not limited thereto, but the formula can be modified in various ways according to actual needs.

[0051] The above optical parts and parameters C 1、 C 2、 …、C m Specifically, the work of OPC is to calibrate the model first to obtain the optical part and parameters C 1、 C 2、 …、C m This part of the work has nothing to do with the correction, and only involves the test pattern (including anchor points) and the corresponding wafer measurement results. After obtaining the OPC model, the design layout can be corrected according to this model. In the actual correction process, the correction program only cares about the simulation signal provided by the model.

[0052] The consumption of simulation time mainly comes from the acquisition of signals, that is, the convolution operation process of the optical part and various kernel functions with the layout. The time consumed by the convolution of the optical part and the layout is about 20-30% of the total simulation time.

[0053] At block 204, a simplified model of the OPC model is generated based on the anchor point and the optical signal portion.

[0054] As mentioned above, the consumption of simulation time mainly comes from the acquisition of signals, that is, the optical part and the convolution operation process of various kernel functions and the layout. In addition, it should be pointed out that the speed of optical simulation is related to the gradient (or slope) of the simulation signal. The larger the gradient of the simulation signal, the faster the simulation speed.

[0055] Refer to the following Figure 4 Give a description. Figure 4 Schematic diagram showing signals with different gradients according to some embodiments of the present disclosure. Figure 4 Two curves and a straight line are shown in FIG. 4 , wherein a curve 402 represents a model signal with a lower gradient, another curve 404 represents a model signal with a higher gradient, and a straight line 406 represents a threshold value of the model. The two curves have the same simulation line width, i.e., CD. For a signal with a higher gradient, the simulation value of the OPC model in the simulation iteration process will converge faster, while for a signal with a lower gradient, the simulation value of the OPC model in the simulation iteration process will converge slower, thereby affecting the simulation speed.

[0056] In some embodiments of the present disclosure, a simulation signal with a higher gradient can be obtained by generating a simplified model, so that the simulation value can converge quickly, thereby accelerating the simulation speed. This will be further described below.

[0057] Usually when using the OPC model for simulation, there are two important pieces of information: the simulation signal value of the corresponding layout and the determined signal threshold. Specifically, during the simulation process, the outline of the graphic can be obtained through the simulation signal value of the corresponding layout and the determined signal threshold, that is, the simulation of the graphic is achieved.

[0058] The signal threshold is a holistic value used to determine whether resolution occurs at that location (i.e., when the signal value and the signal threshold are equal, it is the boundary predicted by the model after the photoresist is developed on the wafer). The signal threshold can be determined by the anchor point (Anchor) and the simulation signal. This is further described later.

[0059] Based on the operating mechanism of the OPC model mentioned above, a fast model (or simplified model) can be designed. In order to distinguish it from the fast model, the commonly used fully calibrated model is called the accurate model (referred to as the OPC model in this article).

[0060] In some embodiments, the fast model can be obtained by: first, extracting the optical signal part of the precise model as the main signal part of the fast model. Secondly, determining the corresponding new signal threshold according to the anchor point and the optical signal part, that is, the signal threshold used to simplify the model.

[0061] Anchor point is an important concept in the photolithography process. An anchor point can be a certain figure selected from a series of measurement figures composed of figures of different sizes, which usually corresponds to the minimum design rule of the process level. The anchor point is used to calibrate the energy of the wafer passing (or parsing) at the corresponding level in the process, so as to calibrate the signal threshold in the OPC model. For each corresponding process level, there is only one anchor point used to determine the exposure energy.

[0062] For example, for a 0.18um process, the polysilicon layer anchor point is 0.18um, and the CD obtained on the wafer is required to be 0.18um. When modeling, it must be ensured that the result of the 0.18um structure simulation is also 0.18um, so as to be consistent with the result required by the wafer. The OPC model must ensure the accuracy of the anchor point data. In some embodiments, the signal threshold can be determined by the anchor point (including the structure of the anchor point, the data on the actual wafer) and the signal obtained by the above simulation.

[0063] In some embodiments, generating a simplified model of the OPC model based on the anchor point and the optical signal part may include: using the optical signal part as the main signal part of the simplified model; generating a simulation signal of the layout from the optical signal part; determining the critical dimension of the graphic in the layout based on the anchor point; and determining the signal threshold of the simplified model based on the critical dimension and the simulation signal.

[0064] In some embodiments, generating a simulation signal of the layout from the optical signal portion may include generating the simulation signal based on the optical signal in the optical signal portion and the layout.

[0065] In some embodiments, the simulation signal of the fast model can be obtained using the following formula:

[0066] new_simulation_signal = optical @layout;

[0067] Among them, new_simulation_signal is the simulation signal generated by the simplified model, optical represents the optical signal in the OPC model, @ represents the convolution symbol, and layout represents the layout. That is, the simulation signal can be obtained by convolving the optical signal in the OPC model with the layout.

[0068] In some embodiments, determining the critical dimension of the graphic based on the anchor point may include: when a simulated line width of the simplified model at the anchor point is consistent with a corresponding measured line width on the wafer, using the simulated line width as the critical dimension.

[0069] In some embodiments, the optical signal portion of the precise model can be extracted as the main signal of the fast model, and the corresponding new signal threshold is determined according to the anchor point. Specifically, the extracted optical portion can generate a simulation signal. To this end, the anchor point is simulated with the extracted optical portion to generate a simulation signal, and then the corresponding new threshold is obtained according to the CD on the wafer corresponding to the anchor point.

[0070] In some embodiments, the simplified model refers to the optical part (the most conservative part) of the accurate model. In actual operation, some other parts, such as the kernel function part, can also be added as needed, but this will affect the running speed to a certain extent. The optical signal in the simulation signal can be generated by the optical part of the model.

[0071] The OPC model is usually constructed in the early stage of process development, and the model remains unchanged when the process remains unchanged. Subsequent normal calibration work relies on the model to correct different layouts.

[0072] In some embodiments, the step of determining a new signal threshold may be based on the following: 1) optical signal (or in addition to the signal that is desired to be included in the simplified model); 2) anchor point information (mask layout, how big the CD is on the mask, how big the CD is on the wafer); 3) assuming that the simulated line width of the simplified model at the anchor point is consistent with the line width measured on the wafer; 4) determining that the signal threshold should be obtained at this time.

[0073] Refer to the following Figure 5 Give a description. Figure 5 FIG. 1 is a schematic diagram showing a method for determining a signal threshold of a simplified model according to some embodiments of the present disclosure. Figure 5 As shown, two curves and two straight lines are shown, wherein the upper curve 502 represents the simulation signal of the simplified model, which has a higher gradient (slope), and the lower curve 504 represents the simulation signal of the accurate model, which has a lower gradient. The lower straight line 406 is the threshold value of the model, and the upper straight line 508 is the threshold value of the simplified model.

[0074] As mentioned before, the anchor point determines the critical dimension CD in the process. Therefore, the value of CD can be determined based on the anchor point. Figure 5 It can be seen that for the same CD value, the two straight lines representing the threshold are located at different heights. In other words, the intersection points of the two straight lines and the curve are located at different heights. When the distribution (curve) of the simulation signal is determined, the threshold value of the simplified model can be determined. Figure 5 It can be seen that the threshold of the simplified model is offset upward by a certain distance relative to the threshold of the OPC model. Therefore, when the threshold of the precise model is known, the signal threshold of the simplified model can be determined. It can be seen that the signal threshold of the simplified model can be obtained by adjusting the signal threshold of the precise model.

[0075] Figure 6 A schematic diagram of a method for determining a simulation signal according to some embodiments of the present disclosure is shown. Figure 6 The upper part of Figure 5 The same as in the previous section, this part will not be repeated. Figure 6 The lower middle part shows the layout 602 and the figure 604 in the layout. The horizontal line 606 in the figure represents a line running through the figure 604. The simulation signals of the simplified model and the simulation signals of the precise model in the figure are formed by connecting the simulation signals on the horizontal line 606. The place where the signal on the curve is equal to the signal threshold is the resolution point (forming the contour). The signal at each point is obtained by convolving the layout centered on this point and the signal in the model. Figure 6 The CD shown in is the line width of the graphic 604. The graphic 604 may be referred to as an anchor point.

[0076] Back to Figure 2 At block 206, a ratio of the optical signal portion to the signal of the OPC model is determined.

[0077] In some embodiments, determining the ratio of the optical signal portion to the signal portion of the OPC model may include: determining the integral of the optical signal in the OPC model, that is, the integral of the optical signal in the entire OPC model. In practice, integration may be performed only in a predetermined area as required, for example, within a range of 1um in length and 1um in width, because the signal decays very quickly outside this range and can be almost ignored. Afterwards, the product of the integral of each kernel function signal of the OPC model and the corresponding coefficient may be determined respectively; and the sum of the sum of each product and the integral may be determined. Finally, the ratio of the integral of the optical signal to the sum may be determined as a ratio.

[0078] In the OPC correction process, the early correction cycles are not a "precise" process, but a "rough" process, that is, if the correction amount calculated according to the model simulation is Δ, it will be multiplied by an attenuation amount μ less than 1 in the initial correction cycle to prevent over-correction from causing trouble in subsequent correction cycles. Therefore, the correction amount at this time is μΔ. The specific μ value of each correction cycle is different. For example, in the early stage, it is around 0.5 (system default value, which can also be specified manually), and in the last few correction cycles, the μ value will be close to 1. In other words, μ is variable, and usually tends to increase with the increase of sequence.

[0079] In some embodiments, the ratio of the optical signal to the signal of the precise model is determined. For example, the ratio of the optical signal portion to the signal portion of the OPC model can be determined using the following formula:

[0080] Where k represents the ratio, optical represents the optical signal in the OPC model, and kernel j represents the signal of the jth kernel function, C j The coefficient of the signal representing the jth kernel function, m is a positive integer, representing the mth kernel function. Generally, the value of k is between 0.7 and 0.95.

[0081] In some embodiments, in each calibration cycle, the attenuation coefficient in each calibration cycle is less than or equal to the attenuation coefficient in the calibration cycle immediately following the calibration cycle.

[0082] In some embodiments, determining a simplified model of the optical proximity correction (OPC) model based on the optical signal and the signal threshold may include: extracting the optical signal portion in the OPC model as the main signal of the simplified model; and using the signal threshold as the signal threshold of the simplified model.

[0083] In some of the above embodiments, the reason why the attenuation coefficient and the ratio are compared and different models are used based on the comparison results is mainly based on the following considerations: the signals of the fast model and the precise model are different, k determines the proportion of the optical part of the fast model as the dominant signal in the precise model, and this proportion determines the similarity between the two to a certain extent. The correction size of the final decision must be determined by the precise model, and the μ value of the current correction cycle represents the "trade-off" of the precise model signal. When the μ value itself does not obtain all the precise signals, the fast model can naturally be used instead. Of course, when using a simplified model, some precision loss may be involved, so it needs to be compensated by the correction of the precise model of at least one last cycle.

[0084] In some embodiments, the OPC correction program optimization process is as follows: the precise model used in all correction cycles with μ<κ is replaced with the fast model, and all subsequent correction cycles with μ>=κ still keep the precise model, which will be further described in conjunction with block 208 .

[0085] At block 208, the layout is corrected to determine a model to be used in the correction cycle based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle.

[0086] As mentioned above, in some embodiments of the present disclosure, it may be determined by comparing the ratio with the attenuation coefficient whether to use different models for OPC correction at different stages.

[0087] In some embodiments, the layout is corrected using the simplified model in a correction cycle in response to the ratio being greater than an attenuation coefficient in the correction cycle.

[0088] Here is an example: Assume that the OPC correction program has 20 correction cycles: the μ value of the first 10 is 0.5, the μ value of the 11th to 15th is 0.6, the μ value of the 16th to 18th is 0.8, the μ value of the 19th is 0.9, and the μ value of the 20th is 1. The κ value corresponding to the fast model is 0.8. The precise model in the first 15 correction cycles can be replaced by the fast model, that is, the fast model is used to perform OPC correction in the first 15 correction cycles. In actual application, it can be adjusted as needed.

[0089] In some embodiments, the layout is corrected using the OPC model in the correction cycle in response to the ratio being not greater than the attenuation factor in the correction cycle.

[0090] For example, for the example mentioned above, the fast model can be replaced by the precision model starting from cycle 16. In the above example, assuming that the μ value is 0.85 starting from cycle 18, the precise model can be used for OPC correction starting from cycle 18.

[0091] In some embodiments, in response to the ratio being not greater than the attenuation coefficient, correcting the layout using the OPC model includes: correcting the layout using the OPC model in the last predetermined number of correction cycles. In other words, no matter how much the μ value changes in the later cycles, the last several cycles can be specified to perform OPC correction using the accurate model.

[0092] In some embodiments, the predetermined number is at least greater than 1. Preferably, the predetermined number is greater than or equal to 3.

[0093] As mentioned above, the precise model used in all correction cycles with μ<κ is replaced by the fast model, and all subsequent correction cycles with μ>=κ still use the precise model. However, at least one correction cycle is retained using the precise model. In this way, it is ensured that the correction result is finally finalized using the precise model.

[0094] Through the embodiments of the present disclosure, the correction results obtained are the same as those obtained by using all accurate models, while the overall simulation time is reduced by about 60%, and the corresponding OPC correction time is also reduced accordingly.

[0095] Some embodiments of the present disclosure provide methods for optical proximity correction. It should be noted that the examples given in the above embodiments are only for illustrating the solutions of the embodiments of the present disclosure, and are not intended to limit the solutions of the present disclosure.

[0096] In some embodiments of the present disclosure, since the optical signal accounts for a large proportion of the simulated signal, a simplified model can be constructed for the optical signal. Different models are used according to the proportion of the optical signal. By using the extracted fast model, a preliminary result can be obtained, which is equivalent to a rough adjustment process, and then a precise model is applied to the preliminary result to obtain high accuracy.

[0097] In some embodiments of the present disclosure, based on the comparison between the ratio and the attenuation coefficient in each correction cycle, it is determined whether to use the optical proximity correction model or the simplified model to correct the layout in each correction cycle. This solution can save computing resources and speed up the process, significantly reduce the time of model simulation and correction, and ensure simulation accuracy.

[0098] It should be understood that the embodiments shown in the drawings are only for schematically illustrating the solutions of some embodiments of the present disclosure and are not intended to limit the present disclosure. The embodiments of the present disclosure may also have various other forms.

[0099] The embodiment of the present disclosure also discloses an electronic device. The electronic device includes: a processor; and a memory coupled to the processor, the memory having instructions stored therein, and when the instructions are executed by the processor, the device performs actions, including: determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on an anchor point and the optical signal portion; determining the ratio of the optical signal portion to the signal portion of the OPC model; and determining the model used in the correction cycle to correct the layout based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle.

[0100] An embodiment of the present disclosure further discloses a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method for optical proximity correction according to the embodiment of the present disclosure is implemented.

[0101] Figure 7 A schematic block diagram of an electronic device according to some exemplary embodiments of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0102] like Figure 7As shown, the device 700 includes a CPU 701, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 702 or a computer program loaded from a storage unit 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the device 700 can also be stored. The CPU 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0103] Multiple components in the device 700 are connected to the I / O interface 705, including: an input unit 706, such as a keyboard, a mouse, etc.; an output unit 707, such as various types of displays, speakers, etc.; a storage unit 708, such as a disk, an optical disk, etc.; and a communication unit 709, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 709 allows the device 700 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0104] The various processes and processing described above, such as method 200, may be executed by CPU 701. For example, in some embodiments, method 200 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as storage unit 708. In some embodiments, part or all of the computer program may be loaded and / or installed on device 700 via ROM 702 and / or communication unit 709. When the computer program is loaded into RAM 703 and executed by CPU 701, one or more steps in method 200 described above may be performed.

[0105] The scheme according to the embodiment of the present disclosure may be a method, an apparatus, a system and / or a computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing various aspects of the present disclosure are loaded. The computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. The computer-readable program instructions may be downloaded from the computer-readable storage medium to various computing / processing devices, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network and / or a wireless network.

[0106] Various embodiments of the present disclosure have been described above, and the above descriptions are exemplary and are only optional embodiments of the present disclosure, not exhaustive, and are not intended to limit the present disclosure. Although the claims in this application have been formulated for specific combinations of features, it should be understood that the scope of the present disclosure also includes any novel features or any novel combination of features disclosed herein, whether or not it relates to the same scheme in any claim currently claimed for protection. The applicant hereby informs that new claims may be formulated into these features and / or combinations of these features during the examination of this application or in any further application derived therefrom.

[0107] The terms used in this article are selected to best explain the principles of each embodiment, practical application or technical improvement in the market, or to enable other ordinary technicians in the field to understand the embodiments disclosed herein. For those skilled in the art, the present disclosure may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A method for optical proximity correction, comprising: Determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on the anchor point and the optical signal portion; determining a ratio of the optical signal portion to the signal portion of the OPC model; as well as Based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle, the model used in the correction cycle is determined to correct the layout; specifically comprising: in response to the ratio being greater than the attenuation coefficient in the correction cycle, the simplified model is used to correct the layout in the correction cycle; And in response to the ratio being not greater than the attenuation factor in the correction cycle, correcting the layout using the OPC model in the correction cycle.

2. The method of claim 1 , wherein generating a simplified model of the OPC model based on an anchor point and the optical signal portion comprises: Using the optical signal part as the main signal part of the simplified model; Generating a simulation signal of the layout from the optical signal portion; Determining a critical size of a graphic in the layout based on the anchor point; as well as A signal threshold of the simplified model is determined based on the critical dimension and the simulation signal.

3. The method according to claim 2, wherein generating a simulation signal of a layout from the optical signal portion comprises: The simulation signal is generated based on the optical signal in the optical signal portion and the layout.

4. The method according to claim 3, wherein the simulation signal is generated using the following formula: new_simulation_signal = optical@layout in, The new_simulation_signal is a simulation signal generated by the simplified model, optical represents an optical signal in the OPC model, @ represents a convolution symbol, and layout represents the layout.

5. The method according to claim 2, wherein determining the critical size of the graphic in the layout based on the anchor point comprises: In response to the simulated line width of the simplified model at the anchor point being consistent with the corresponding measured line width on the wafer, the simulated line width is used as the critical dimension.

6. The method of claim 1 , wherein determining the ratio of the optical signal portion to the signal portion of the OPC model comprises: determining an integral of an optical signal in the OPC model; Determine the product of the integral of each kernel function signal of the OPC model and the corresponding coefficient respectively; determining a sum of the sum of each of the products and the integral; as well as The ratio is determined as the ratio of the integral of the optical signal to the sum value.

7. The method of claim 6, wherein determining the ratio of the optical signal portion to the signal portion of the OPC model comprises calculating the ratio using the following formula: in, k represents the ratio, optical represents the optical signal in the OPC model, kernelj represents the signal of the jth kernel function, C j represents the coefficient of the signal of the j-th kernel function, m is a positive integer, represents the m-th kernel function, and x and y represent the position coordinates in the OPC model.

8. The method of claim 1 , wherein in response to the ratio being not greater than the attenuation coefficient in the correction cycle, correcting the layout using the OPC model in the correction cycle comprises: The layout is corrected using the OPC model in a final predetermined number of correction cycles. The method according to claim 8 , wherein the predetermined number is greater than or equal to 3.

10. The method of claim 1, wherein: In each calibration cycle, the attenuation coefficient in each calibration cycle is less than or equal to the attenuation coefficient in the calibration cycle immediately following the calibration cycle.

11. An electronic device, comprising: processor; as well as A memory coupled to the processor, the memory having instructions stored therein, the instructions causing the device to perform actions when executed by the processor, the actions comprising: Determining an optical signal portion in an optical proximity correction (OPC) model; generating a simplified model of the OPC model based on the anchor point and the optical signal portion; determining a ratio of the optical signal portion to the signal portion of the OPC model; and Based on the numerical relationship between the ratio and the attenuation coefficient in the correction cycle, the model used in the correction cycle is determined to correct the layout; specifically including: in response to the ratio being greater than the attenuation coefficient in the correction cycle, the simplified model is used to correct the layout in the correction cycle; and in response to the ratio being not greater than the attenuation coefficient in the correction cycle, the OPC model is used to correct the layout in the correction cycle.

12. A computer-readable storage medium having machine-executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the method according to any one of claims 1 to 10.

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