Methods, apparatus and media for lithographic simulation

Abstract

The embodiment of the invention relates to a method, equipment and medium for photoetching simulation. The method proposed herein comprises: determining, from an initial optical signal, a plurality of optical signal components corresponding to a plurality of photolithography in a lithographic process; adjusting each optical signal component in the plurality of optical signal components based on the process parameters corresponding to the multiple exposures, so as to determine a target optical signal related to the photoetching process; and at least based on the target optical signal, determining the simulated morphology of the photoresist after the photoetching process.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate generally to the field of semiconductor technology, and more particularly, to methods, apparatuses, and media for lithography simulation. Background Art

[0002] Photolithography is one of the key processes in semiconductor manufacturing. At present, some semiconductor processes require the use of thicker photoresists (for example, photoresists with a thickness of more than 5um). In the face of such thick photoresists, a photolithography process with two or even multiple exposures is required to ensure that the pattern can be accurately transferred to the target substrate.

[0003] Lithography simulation aims to break through the hardware limitations of the minimum exposure size by improving software technologies such as resolution without changing the hardware environment. However, traditional lithography simulation is difficult to capture the complex changes in the multiple exposure process, resulting in a large deviation between the simulation results and the actual process. Summary of the invention

[0004] In a first aspect of the present disclosure, a method for photolithography simulation is provided. The method comprises: determining a plurality of optical signal components corresponding to multiple photolithography in a photolithography process from an initial optical signal; adjusting each of the plurality of optical signal components based on process parameters corresponding to each of the multiple exposures to determine a target optical signal related to the photolithography process; and determining a simulated morphology of a photoresist after the photolithography process based at least on the target optical signal.

[0005] In a second aspect of the present disclosure, an electronic device is provided. The device includes at least one processor; and at least one memory, the at least one memory is coupled to the at least one processor and stores instructions for execution by the at least one processor. When the instructions are executed by the at least one processor, the device executes the method of the first aspect.

[0006] In a third aspect of the present disclosure, a computer-readable storage medium is provided, wherein computer-executable instructions are stored on the computer-readable storage medium, and the computer-executable instructions can be executed by a processor to implement the method of the first aspect.

[0007] In a fourth aspect of the present disclosure, a computer program product is provided, which includes computer executable instructions, which, when executed by a processor, implement the method according to the first aspect of the present disclosure.

[0008] It should be understood that the contents described in this content section are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein: Figure 1 A schematic diagram showing an example environment in which various embodiments of the present disclosure can be implemented; Figure 2 A flowchart showing an example process of a method for lithography simulation according to some embodiments of the present disclosure; Figure 3 A schematic diagram showing an example of multiple exposure according to some embodiments of the present disclosure; Figure 4 A block diagram of an electronic device is shown in which one or more embodiments of the present disclosure may be implemented. DETAILED DESCRIPTION

[0010] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0011] It should be noted that the titles of any sections / subsections provided herein are not restrictive. Various embodiments are described throughout this article, and any type of embodiment may be included under any section / subsection. In addition, the embodiments described in any section / subsection may be combined in any manner with any other embodiments described in the same section / subsection and / or different sections / subsections.

[0012] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may be included below. The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may be included below.

[0013] As briefly described above, some semiconductor processes require the use of photoresists with a thickness exceeding 5μm. Such semiconductor processes include, but are not limited to, semiconductor processes based on complementary metal oxide semiconductor image sensors (CIS). Due to the increase in the thickness of the photoresist (the thickness of the photoresist in conventional semiconductor processes is generally around 1μm), it is difficult to achieve accurate transfer of the pattern using a traditional photolithography process with a single exposure. Therefore, in actual operation, it is usually necessary to use a photolithography process with two or even multiple exposures to ensure that the pattern can be accurately transferred to the target substrate.

[0014] However, traditional lithography simulation is mainly designed and optimized based on single-exposure lithography processes. When faced with lithography processes with multiple exposures, traditional lithography simulation technology is difficult to capture the complex changes in the multiple exposure process, resulting in a large deviation between the simulation results and the actual process.

[0015] In view of this, an embodiment of the present disclosure provides a scheme for photolithography simulation. According to the scheme, first, multiple optical signal components corresponding to multiple photolithography in the photolithography process are determined from the initial optical signal. Then, based on the process parameters corresponding to each of the multiple exposures, each of the multiple optical signal components is adjusted to determine a target optical signal related to the photolithography process. Then, based at least on the target optical signal, the simulated morphology of the photoresist after the photolithography process is determined.

[0016] It can be more clearly understood from the description below that the scheme of the present disclosure splits the optical signal (such as the initial optical signal) in the lithography process into multiple optical signal components corresponding to multiple exposures. On this basis, the scheme of the present disclosure compensates each optical signal component based on the process parameters corresponding to each of the multiple exposures, so that each compensated optical signal component is highly matched with the actual process conditions of each exposure. Next, the scheme of the present disclosure reconstructs the optical signal (such as the target optical signal) based on each compensated optical signal component. The reconstructed optical signal can more accurately reflect the complex changes in the multiple exposure process. Based on such an optical signal, the lithography simulation results can be closer to the actual process of multiple exposures, thereby improving the reliability of the lithography simulation.

[0017] In practical applications, especially in semiconductor processes based on CIS that require thick photoresist, this optical signal deconstruction-compensation-reconstruction solution can effectively improve the accuracy of lithography simulation and improve production efficiency.

[0018] Various example implementations of the solution will be described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 A schematic diagram of an example environment 100 is shown in which various embodiments of the present disclosure can be implemented. Figure 1 , the example environment 100 may generally include an electronic device 110 , a target layout 120 , lithography simulation results 130 , and a user 140 .

[0020] The target layout 120 is used to indicate the pattern or structure to be formed on the photoresist during the photolithography process. The user 140 can interact with the electronic device 110 through a terminal device (not shown in the figure) or directly to obtain the photolithography simulation result 140 for the photoresist. For example, the electronic device 110 receives the photolithography simulation request of the user 140, and the photolithography simulation request may include the process parameters and the target layout 120 related to the photolithography process input by the user 140. Then, the electronic device 110 simulates the changes of the photoresist during the photolithography process based on the received process parameters and the target layout 120, such as the photolithography simulation model, so as to obtain the photolithography simulation result 140. The photolithography simulation result 140 can indicate the simulated morphology of the photoresist after the photolithography process, and the photolithography simulation model can include but is not limited to the optical proximity correction (OPC) model, etc. The electronic device 110 can output the photolithography simulation result 140 as feedback to the photolithography simulation request. The user 140 can analyze the lithography simulation result 140 to evaluate the accuracy and stability of the lithography process, and adjust the process parameters of the lithography process as needed to optimize the lithography effect, etc.

[0021] In the example environment 100 , the electronic device 110 may be any type of device with computing capabilities, such as a terminal device or a server device.

[0022] In some embodiments, the terminal device can be any type of mobile terminal, fixed terminal or portable terminal, including a mobile phone, a desktop computer, a laptop computer, a notebook computer, a netbook computer, a tablet computer, a media computer, a multimedia tablet, a personal communication system (PCS) device, a personal navigation device, a personal digital assistant (PDA), an audio / video player, a digital camera / camcorder, a positioning device, a television receiver, a radio broadcast receiver, an e-book device, a gaming device or any combination of the foregoing, including accessories and peripherals of these devices or any combination thereof.

[0023] In some embodiments, the server device may be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content distribution networks, and big data and artificial intelligence platforms. The server device may include, for example, a computing system / server, such as a mainframe, an edge computing node, a computing device in a cloud environment, and the like.

[0024] It should be understood that the structure and function of the various elements in the environment 100 are described for exemplary purposes only and do not imply any limitation on the scope of the present disclosure.

[0025] Figure 2 A flow chart of an example process 200 of a method for lithography simulation according to some embodiments of the present disclosure is shown. The process 200 may be implemented at the electronic device 110.

[0026] Reference Figure 2 In block 210 , the electronic device 110 determines, from the initial optical signal, a plurality of optical signal components corresponding to a plurality of photolithography passes in a photolithography process.

[0027] The photolithography process may refer to a process of transferring the pattern on the mask to the photoresist using an optical system. The photolithography process includes but is not limited to the steps of coating, exposure, development, etching and stripping. In the exposure step, the light emitted by the light source is projected onto the substrate coated with the photoresist through the mask. After the development step, a pattern corresponding to the mask will be formed on the photoresist on the substrate. For thick photoresist, in order to accurately form a pattern on it, a photolithography process with multiple exposures can be used. Through multiple exposures, the limitation of single exposure on accuracy can be broken, thereby achieving a better pattern transfer effect.

[0028] Photoresist, also known as photoresist, is a thin film material that resists etching. In the photolithography process, photoresist is used as an anti-corrosion coating to provide necessary protection for the surface processing of semiconductor materials. The main components of photoresist include polymers, photoinitiators and solvents, etc. These components will undergo chemical changes under the irradiation of light, thereby changing the solubility of photoresist.

[0029] The photoresist may be a positive photoresist or a negative photoresist, and the embodiments of the present disclosure do not limit this. The solubility of the positive photoresist increases after exposure, while the solubility of the negative photoresist decreases after exposure. In some applications, such as CIS process, the photoresist has a relatively large thickness, for example, the thickness of the photoresist is greater than or equal to 5 μm (the thickness of the conventional process photoresist is generally about 1 μm). Such thick photoresist can, for example, provide better pattern transfer accuracy and a wider process window.

[0030] The exposure method can be selected according to the process requirements, and the embodiments of the present disclosure do not limit this. For example, the exposure method includes but is not limited to ultraviolet (UV) or extreme ultraviolet (EUV).

[0031] For the convenience of discussion, the initial optical signal and the target optical signal mentioned below are also referred to as optical signals separately or collectively herein. The optical signal may refer to a characteristic representation of at least one optical parameter of the optical system. In some embodiments, the optical signal may indicate at least one of the following: the wavelength, numerical aperture, refractive index, and / or light source shape of the optical system. In some embodiments, the optical signal may be represented by a kernel function, etc.

[0032] In some embodiments, the electronic device 110 may split the initial optical signal according to the number of exposures of the photolithography process, thereby obtaining optical signal components corresponding to each exposure. In some embodiments, the optical signal components may indicate the wavelength, numerical aperture, refractive index, and / or light source shape involved in the corresponding exposure.

[0033] It should be noted that the above description of the optical signal and the optical signal component is only an example, which does not constitute a limitation on the embodiments of the present disclosure. According to actual needs, the optical signal and the optical signal component can also indicate more content, for example, the optical signal and the optical signal component can also indicate the inner diameter and / or outer diameter of the light source. The optical signal and the optical signal component can also be represented by other forms besides the kernel function. The embodiments of the present disclosure are not listed one by one here.

[0034] In block 220 , the electronic device 110 adjusts each of the plurality of optical signal components based on process parameters corresponding to each of the plurality of exposures to determine a target optical signal related to the photolithography process.

[0035] Process parameters may refer to a series of specific values ​​or conditions used to guide the exposure process in the photolithography process. As an example, process parameters include, but are not limited to, depth of focus, focus offset, and / or exposure energy. It should be noted that the above description of process parameters is only an example, which does not constitute a limitation on the embodiments of the present disclosure. According to actual needs, process parameters may also include more content, and the embodiments of the present disclosure are not listed one by one here.

[0036] For each optical signal component, the electronic device 110 may adjust the optical signal component based on the process parameters involved in the corresponding exposure. For example, for a given exposure corresponding to a given optical signal component, the electronic device 110 may adjust the given optical signal component according to the focal depth, focus offset, and exposure energy involved in the given exposure, thereby compensating the given optical signal component to better match the actual process conditions of the corresponding exposure.

[0037] In some embodiments, the process parameters corresponding to each of the multiple exposures include at least exposure energy. The electronic device 110 adjusts each of the multiple optical signal components based at least on the relative relationship between the exposure energy corresponding to each of the multiple exposures and the reference exposure energy.

[0038] Exposure energy may refer to the energy of light irradiated onto a unit area of ​​photoresist. In some embodiments, the reference exposure energy may be given by a user, or may be determined based on multiple exposure energies corresponding to multiple exposures. For each exposure in the multiple exposures, the electronic device 110 may determine the relative relationship between the exposure energy corresponding to the exposure and the reference exposure energy by any appropriate comparison method. For example, the electronic device 110 may determine the relative relationship between the exposure energy and the reference exposure energy based on a ratio, a difference, or a more complex mathematical relationship between the exposure energy and the reference exposure energy.

[0039] As an example, the relative relationship between the exposure energy corresponding to each exposure and the reference exposure energy can be used to adjust the weight of each optical signal component when reconstructing an optical signal (e.g., a target optical signal), so that the reconstructed optical signal can better adapt to the differences in exposure energy between multiple exposures. As an example, for a certain exposure among multiple exposures, if the relative relationship between the corresponding exposure energy and the reference exposure energy indicates that the exposure energy is at a higher energy level among the multiple exposures, then the electronic device 110 can make the optical signal component corresponding to the exposure have a larger weight when reconstructing the optical signal. Conversely, if the relative relationship between the corresponding exposure energy and the reference exposure energy indicates that the exposure energy is at a lower energy level among the multiple exposures, then the electronic device 110 can make the optical signal component corresponding to the exposure have a smaller weight when reconstructing the optical signal.

[0040] In some embodiments, the reference exposure energy is determined based on the sum of the exposure energies corresponding to the multiple exposures, so as to help the electronic device 110 determine the energy level of the exposure energy corresponding to each exposure in the total exposure energy of the multiple exposures.

[0041] It should be noted that the above method for determining the reference exposure energy is only an example. According to actual needs, the reference exposure energy can be determined in more ways. For example, the reference exposure energy can also be determined based on the central value or optimal value of the exposure energies corresponding to multiple exposures. The embodiments of the present disclosure will not be listed one by one here.

[0042] In some embodiments, the multiple exposures include a first exposure and a second exposure located after the first exposure, and the optical signal components corresponding to the multiple exposures include a first optical signal component corresponding to the first exposure and a second optical signal component corresponding to the second exposure. And the electronic device 110 can adjust each optical signal component in the following manner. First, the electronic device 110 determines the first adjustment coefficient corresponding to the first optical signal component based on the ratio between the exposure energy corresponding to the first exposure and the reference exposure energy. And the electronic device 110 determines the first adjustment coefficient corresponding to the second optical signal component based on the ratio between the exposure energy corresponding to the second exposure and the reference exposure energy. Then, the electronic device 110 determines the adjusted first optical signal component based at least on the product of the first optical signal component and the corresponding first adjustment coefficient. And the electronic device 110 determines the adjusted second optical signal component based at least on the product of the second optical signal component and the corresponding first adjustment coefficient.

[0043] The first exposure and the second exposure may be any exposure in the multiple exposures. Assuming that the first exposure is the first exposure in the multiple exposures, and the second exposure is the second exposure in the multiple exposures, the first optical signal component corresponding to the first exposure is , the second optical signal component corresponding to the second exposure is The electronic device 110 generates a first optical signal component based on the first optical signal component. The corresponding first adjustment coefficient is for the first optical signal component The adjustment process can be expressed by formula (1): ; (1) in is the first optical signal component The corresponding first adjustment coefficient is, is the exposure energy corresponding to the first exposure, D2 is the exposure energy corresponding to the second exposure, is the first optical signal component After the first adjustment factor The adjusted optical signal component.

[0044] The electronic device 110 generates a signal based on the second optical signal component. The corresponding first adjustment coefficient is applied to the second optical signal component The adjustment process can be expressed by formula (2): ; (2) in is the second optical signal component The corresponding first adjustment coefficient is, is the second optical signal component After the first adjustment factor The adjusted optical signal component.

[0045] In this way, the electronic device 110 can quickly and accurately adjust each optical signal component to adapt each optical signal component to the actual exposure energy of the corresponding exposure.

[0046] It should be noted that the above formulas and parameters related to the adjustment of the optical signal components are only exemplary, and do not constitute a limitation on the embodiments of the present disclosure. Other formulas and parameters may also be used to adjust the optical signal components according to actual needs.

[0047] In some embodiments, the process parameters corresponding to each of the multiple exposures include at least a focus shift and a focal depth. The electronic device 110 adjusts each of the multiple optical signal components based at least on the difference between the focal depth corresponding to each of the multiple exposures and the reference focal depth and the reference focus shift.

[0048] Depth of focus can refer to the axial range within which an optical system maintains a clear image in the imaging space. When the exposure position deviates from the ideal focal plane, a defocus effect is introduced, the extent of which can be represented by the focus shift, which can be approximated as the difference between the depth of focus and the ideal focal plane.

[0049] As an example, the electronic device 110 may determine the difference between the focal depth corresponding to each exposure and the reference focal depth by any appropriate comparison method. For example, the electronic device 110 may determine the difference between the focal depth corresponding to a given exposure and the reference focal depth by a difference, a ratio, or a more complex mathematical relationship between the two.

[0050] As an example, the reference focal depth may be given by a user or determined based on the focal depth corresponding to multiple exposures. Similarly, the reference focus offset may be given by a user or determined based on the focus offset corresponding to multiple exposures.

[0051] Figure 3 A schematic diagram of an example 300 of multiple exposures according to some embodiments of the present disclosure is shown. Figure 3, a photoresist 303 is formed on a substrate 304. Assume that the multiple exposures of the photolithography process include a first exposure 301 and a second exposure 302. At the same position of the photoresist 303, for the ideal focal plane F0, the focal depth corresponding to the first exposure is F1, and the focal depth corresponding to the second exposure is F2. That is to say, at the same position of the photoresist 303, as the number of exposures increases, the focal depth corresponding to the exposure (from the same ideal focal plane) is also gradually increasing. The electronic device 110 can determine the change in focal depth of each exposure based on the difference between the focal depth corresponding to each exposure and the reference focal depth (such as focal depth F1 or other values). Next, the electronic device 110 can dynamically adjust the reference focus offset based on this change, so as to determine the actual focus offset corresponding to each exposure. Then, the electronic device 110 can adjust the optical signal component corresponding to each exposure based on the actual focus offset corresponding to each exposure.

[0052] As an example, the actual focus offset can be used to adjust the weight of the corresponding optical signal component when reconstructing the optical signal (e.g., the target optical signal), so that the reconstructed optical signal can better adapt to the difference in focus offsets between multiple exposures. As an example, for a certain exposure (e.g., the first exposure 301) among the multiple exposures, if the actual focus offset corresponding to it is small, the electronic device 110 can make the optical signal component corresponding to the exposure have a smaller weight when reconstructing the optical signal. Conversely, for a certain exposure (e.g., the second exposure 302) among the multiple exposures, if the actual focus offset corresponding to it is large, the electronic device 110 can make the optical signal component corresponding to the exposure have a larger weight when reconstructing the optical signal. In this way, the electronic device 110 can keep each optical signal component matching the actual focus offset of the corresponding exposure.

[0053] In some embodiments, the reference focal depth is determined based on the focal depth corresponding to the first exposure in the multiple exposures. Alternatively or additionally, the reference focus offset is determined based on the focus offset corresponding to the first exposure in the multiple exposures. In this way, the electronic device 110 can minimize the introduction of parameters, thereby simplifying the calculation process.

[0054] In some embodiments, the multiple exposures include a first exposure and a second exposure located after the first exposure, and the optical signal components corresponding to the multiple exposures include a first optical signal component corresponding to the first exposure and a second optical signal component corresponding to the second exposure. The electronic device 110 can adjust each optical signal component in the following manner. First, the electronic device 110 superimposes the difference between the focal depth corresponding to the first exposure and the reference focal depth on the reference focus offset to determine the second adjustment coefficient corresponding to the first optical signal component. In addition, the electronic device 110 superimposes the difference between the focal depth corresponding to the second exposure and the reference focal depth on the reference focus offset to determine the second adjustment coefficient corresponding to the second optical signal component. Then, the electronic device 110 determines the adjusted first optical signal component based at least on the product of the first optical signal component and the corresponding second adjustment coefficient. In addition, the electronic device 110 determines the adjusted second optical signal component based at least on the product of the second optical signal component and the corresponding second adjustment coefficient.

[0055] As an example, continue to refer to Figure 3 , assuming that the first exposure 301 is the first exposure in the multiple exposures, the second exposure 302 is the second exposure in the multiple exposures, the reference focus offset is the focus offset defocus corresponding to the first exposure 301, and the reference focal depth is the focal depth F1 corresponding to the first exposure 301. The electronic device 110 generates a first optical signal component based on the first optical signal component. The corresponding second adjustment coefficient is The adjustment process can be expressed by formula (3): ; (3) in is the first optical signal component The corresponding second adjustment coefficient is, is the first optical signal component After the second adjustment factor Adjusted optical signal component, DE1=defocus , or DE1 can also take other values.

[0056] The electronic device 110 generates a signal based on the second optical signal component. The corresponding second adjustment coefficient is The adjustment process can be expressed by formula (4): ; (4) in is the second optical signal component The corresponding second adjustment coefficient is, is the second optical signal component After the second adjustment factor Adjusted optical signal component, DE2= , or DE2 can also take other values.

[0057] In this way, the electronic device 110 can quickly and accurately adjust each optical signal component to adapt the each optical signal component to the actual focus shift of the corresponding exposure.

[0058] It should be noted that the above formulas and parameters related to the adjustment of the optical signal components are only exemplary and do not constitute a limitation to the embodiments of the present disclosure. Other formulas and parameters may be used to adjust the optical signal components according to actual needs.

[0059] In some embodiments, the electronic device 110 may adjust the multiple optical signal components by using formula (1) and formula (2). Alternatively, the electronic device 110 may adjust the multiple optical signal components by using formula (3) and formula (4). Alternatively, the electronic device 110 may adjust the multiple optical signal components by using formula (1) to formula (4). The specific adjustment may be determined according to actual needs, and the embodiments of the present disclosure are not limited thereto.

[0060] In some embodiments, the target optical signal indicates at least one of the following: wavelength, numerical aperture, refractive index, light source shape, and / or light source parameters. If not described in detail here, it can be determined by referring to the description of the initial optical signal in the above text, so the embodiments of the present disclosure will not be repeated here.

[0061] In some embodiments, the electronic device 110 determines the target optical signal by summing the adjusted plurality of optical signal components.

[0062] In some embodiments, the electronic device 110 may determine the target optical signal by directly superimposing the adjusted multiple optical signal components. Alternatively, the electronic device 110 may also determine the target optical signal by weighted summing the adjusted multiple optical signal components. Assuming that the electronic device 110 adjusts the multiple optical signal components by formulas (1) to (4), the electronic device 110 determines the target optical signal The process can be expressed by formula (5): . (5) In some embodiments, to ensure the accuracy of the target optical signal, the electronic device 110 may perform a calibration operation on at least one process parameter involved in calculating the target optical signal.

[0063] In some embodiments, the exposure energy and focal depth corresponding to each exposure are measurable process parameters. That is, these process parameters can be accurately determined by appropriate measurement methods. In this case, referring to formula (5), During the calculation of As an example, in some embodiments, the initial value of the reference focus offset may be determined based on the focal depth corresponding to the first exposure in multiple exposures. After determining the initial value of the reference focus offset, the electronic device 110 may perform a calibration operation on the initial value. Specifically, the electronic device 110 performs a calibration operation on the exposure energy D1, D2, and the optical signal component D2. , and depth of focus In the case of no change, a specific algorithm or program is used to gradually adjust the initial value within a certain range. After each adjustment, the electronic device 110 can recalculate the target optical signal Optical and compare it with the expected target value. Through continuous iteration and adjustment, until the reference focus offset that makes the target optical signal Optical closest to the expected target value is found, the calibration operation of the reference focus offset is completed.

[0064] In this way, the embodiments of the present disclosure minimize the introduction of process parameters that require calibration while ensuring the accuracy of the optical signal.

[0065] Once the target optical signal is determined, at block 230 , the electronic device 110 determines a simulated topography of the photoresist 303 after the photolithography process based at least on the target optical signal.

[0066] In some embodiments, the electronic device 110 can construct a photolithography simulation model based at least on the target optical signal. Then, the electronic device 110 uses the photolithography simulation model to determine the simulated morphology of the photoresist 303 after the photolithography process. As an example, the photolithography simulation model includes but is not limited to the OPC model, etc. The OPC model is intended to solve the mutual influence problem between adjacent graphics caused by effects such as diffraction and interference of light in the photolithography process. The OPC model can consider in detail the chemical reaction process of the photoresist 303 under the action of light and the subsequent development process, and simultaneously, in combination with the analysis and correction method of the proximity effect of the OPC model, the reaction of the photoresist 303 is corrected.

[0067] After calculation and analysis of the photolithography simulation model, the electronic device 110 finally determines the simulated morphology of the photoresist 303 after the photolithography process. The simulated morphology can be presented in various forms, such as three-dimensional graphics, contour maps, or data tables. By comparing the simulated morphology with the target morphology required by the design, the user 140 can determine whether the current photolithography process parameters are reasonable, and then analyze whether they need to be adjusted and optimized.

[0068] In some embodiments, the electronic device 110 constructs a photolithography simulation model for the photoresist 303 based on the target optical signal and at least one kernel function related to the photolithography process. Then, the electronic device 110 uses the photolithography simulation model to determine the simulated morphology of the photoresist 303 after the photolithography process.

[0069] In some embodiments, at least one kernel function indicates the influence of various physical phenomena and effects in the lithography process on the morphology of the photoresist 303. With the help of these kernel functions, the lithography simulation model can introduce additional information to supplement the target optical signal, thereby improving the accuracy of lithography simulation.

[0070] In some embodiments, at least one kernel function indicates at least one of the following: a loading effect in a lithography process, and / or a physical effect of a predetermined shape in a lithography process. In this way, the electronic device 110 can maximize the accuracy of lithography simulation with less introduction of kernel functions.

[0071] In some embodiments, the electronic device 110 constructs a lithography simulation model by performing weighted fusion on the target optical signal and at least one kernel function based on a first weight corresponding to the target optical signal and a second weight corresponding to each of the at least one kernel function. The first weight is greater than the second weight.

[0072] In the embodiment of the present disclosure, after the optical signal is reconstructed as described above, it can fully reflect the complex changes of multiple exposures. By making the target optical signal have the first weight in the lithography simulation, the electronic device 110 only needs to select a small number of kernel functions to achieve the simulation accuracy that requires a large number of kernel functions in the traditional solution, thereby greatly improving the efficiency of the lithography simulation.

[0073] As an example, the lithography simulation model can be expressed by formula (6): simulation_signal = [C1*Optical + C 21 *Kernel1+ C 22 *Kernel2+ … + C 2m *Kernel m ] @ layout; (6) Where C1 represents the first weight, Kernel1, Kernel2, ..., Kernel m represents m kernel functions, C 21 , C 22 , ..., C 2m represents the m second weights corresponding to the m kernel functions, [C1*Optical + C 21 *Kernel1+ C 22*Kernel2+ … + C 2m *Kernel m ] represents the lithography simulation model, layout represents the target layout 120, @ represents the convolution symbol, * represents the product symbol, and simulation_signal represents the output of the lithography simulation model. As an example, the first weight C1 can be "1", C 21 , C 22 , ..., C 2m Can be the same or different, C 21 , C 22 , ..., C 2m The sum can be "1".

[0074] It should be noted that, according to actual needs, at least one kernel function may also include other kernel functions in addition to the above kernel functions, so as to further improve the accuracy of lithography simulation. In addition, in some applications, the kernel function may not be used, so as to maximize the simulation speed of the lithography simulation model.

[0075] Through the foregoing description, it can be more clearly understood that the embodiments of the present disclosure split, compensate and reconstruct the optical signal. The compensation of each optical signal component based on process parameters such as exposure energy and depth of focus enables these optical signal components to fully reflect the mutual correlation between each other, so that the reconstructed optical signal can be closer to the physical essence of multiple exposures. Based on this, the embodiments of the present disclosure do not need to introduce a large number of kernel functions for supplementation. In this way, on the one hand, the simulation speed of the lithography simulation model can be prevented from slowing down, and on the other hand, the risk of overfitting can be reduced.

[0076] Figure 4 1 is a block diagram of an electronic device 400 in which one or more embodiments of the present disclosure may be implemented. The electronic device 400 may be used to implement, for example, Figure 1 The electronic device 110 shown. It should be understood that Figure 4 The electronic device 400 shown is merely exemplary and should not constitute any limitation on the functionality and scope of the embodiments described herein.

[0077] Reference Figure 4 , the electronic device 400 is in the form of a general electronic device. The components of the electronic device 400 may include, but are not limited to, one or more processors 410, a memory 420, a storage device 430, one or more communication units 440, one or more input devices 450, and one or more output devices 460. The processor 410 may be an actual or virtual processor and is capable of performing various processes according to a program stored in the memory 420. In a multi-processor system, multiple processors execute computer executable instructions in parallel to improve the parallel processing capability of the electronic device 400.

[0078] The electronic device 400 typically includes a plurality of computer storage media. Such media can be any available media accessible to the electronic device 400, including but not limited to volatile and non-volatile media, removable and non-removable media. The memory 420 can be a volatile memory (e.g., registers, caches, random access memory (RAM)), a non-volatile memory (e.g., a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), flash memory), or some combination thereof. The storage device 430 can be a removable or non-removable medium, and can include a machine-readable medium, such as a flash drive, a disk, or any other medium, which can be used to store information and / or data and can be accessed within the electronic device 400.

[0079] The electronic device 400 may further include additional removable / non-removable, volatile / non-volatile storage media. Figure 4 As shown in , a disk drive for reading or writing from a removable, non-volatile disk (e.g., a "floppy disk") and an optical drive for reading or writing from a removable, non-volatile optical disk may be provided. In these cases, each drive may be connected to the bus (not shown) by one or more data media interfaces. The memory 420 may include a computer program product 425 having one or more program modules that are configured to perform various methods or actions of various embodiments of the present disclosure.

[0080] The communication unit 440 implements communication with other electronic devices through a communication medium. Additionally, the functions of the components of the electronic device 400 can be implemented with a single computing cluster or multiple computing machines that can communicate through a communication connection. Therefore, the electronic device 400 can operate in a networked environment using a logical connection with one or more other servers, a network personal computer (PC), or another network node.

[0081] The input device 450 may be one or more input devices, such as a mouse, a keyboard, a tracking ball, etc. The output device 460 may be one or more output devices, such as a display, a speaker, a printer, etc. The electronic device 400 may also communicate with one or more external devices (not shown) through the communication unit 440 as needed, such as a storage device, a display device, etc., communicate with one or more devices that allow a user to interact with the electronic device 400, or communicate with any device that allows the electronic device 400 to communicate with one or more other electronic devices (e.g., a network card, a modem, etc.). Such communication may be performed via an input / output (I / O) interface (not shown).

[0082] According to an exemplary implementation of the present disclosure, a computer-readable storage medium is provided, on which computer-executable instructions are stored, wherein the computer-executable instructions are executed by a processor to implement the method described above. According to an exemplary implementation of the present disclosure, a computer program product is also provided, which is tangibly stored on a non-transitory computer-readable medium and includes computer-executable instructions, and the computer-executable instructions are executed by a processor to implement the method described above.

[0083] Various aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of the methods, devices, equipment, and computer program products implemented according to the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer-readable program instructions.

[0084] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so as to produce a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device for implementing the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions make the computer, programmable data processing device, and / or other equipment work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0085] Computer-readable program instructions can be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operational steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, so that the instructions executed on the computer, other programmable data processing apparatus, or other device implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0086] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple implementations of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of a module, program segment or instruction includes one or more executable instructions for realizing the logical function of the specification. In some implementations as replacements, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be realized by a special hardware-based system that performs the function or action of the specification, or can be realized by a combination of special hardware and computer instructions.

[0087] The above descriptions of various implementations of the present disclosure are exemplary, non-exhaustive, and not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described implementations. The determination of the terms used herein is intended to best explain the principles of the implementations, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the various implementations disclosed herein.

Claims

1. A method for photolithography simulation, characterized in that: include: From the initial optical signal, determining a plurality of optical signal components corresponding to a plurality of exposures in a photolithography process; Based on the process parameters corresponding to the multiple exposures, respectively, adjusting each of the multiple optical signal components to determine a target optical signal related to the photolithography process; as well as Based at least on the target optical signal, a simulated morphology of the photoresist after the photolithography process is determined.

2. The method according to claim 1, characterized in that The process parameters corresponding to each of the multiple exposures include at least exposure energy, and Wherein adjusting each of the plurality of optical signal components comprises: Based at least on a relative relationship between the exposure energy corresponding to each of the multiple exposures and a reference exposure energy, each of the multiple optical signal components is adjusted.

3. The method according to claim 2, characterized in that The reference exposure energy is determined based on the sum of the exposure energies corresponding to the multiple exposures.

4. The method according to claim 2 or 3, characterized in that: The multiple exposures include a first exposure and a second exposure subsequent to the first exposure, the optical signal components corresponding to the multiple exposures include a first optical signal component corresponding to the first exposure and a second optical signal component corresponding to the second exposure, and Wherein adjusting each of the plurality of optical signal components comprises: determining a first adjustment coefficient corresponding to the first optical signal component based on a ratio between the exposure energy corresponding to the first exposure and the reference exposure energy, determining a first adjustment coefficient corresponding to the second optical signal component based on a ratio between the exposure energy corresponding to the second exposure and the reference exposure energy, determining an adjusted first optical signal component based at least on a product of the first optical signal component and a corresponding first adjustment coefficient, and An adjusted second optical signal component is determined based at least on a product of the second optical signal component and a corresponding first adjustment coefficient.

5. The method according to claim 1, characterized in that The process parameters corresponding to each of the multiple exposures include at least focal depth, and Wherein adjusting each of the plurality of optical signal components comprises: Based at least on a difference between a focal depth corresponding to each exposure in the multiple exposures and a reference focal depth and a reference focus offset, each of the multiple optical signal components is adjusted.

6. The method according to claim 5, characterized in that The reference focal depth is determined based on the focal depth corresponding to the first exposure in the multiple exposures, and / or The reference focus shift is determined based on a focus shift corresponding to a first exposure in the multiple exposures.

7. The method according to any one of claims 5 or 6, characterized in that The multiple exposures include a first exposure and a second exposure located after the first exposure, and the optical signal components corresponding to the multiple exposures include a first optical signal component corresponding to the first exposure and a second optical signal component corresponding to the second exposure; and Wherein adjusting each of the plurality of optical signal components comprises: superimposing a difference between the focal depth corresponding to the first exposure and the reference focal depth on the reference focal shift to determine a second adjustment coefficient corresponding to the first optical signal component, superimposing the difference between the focal depth corresponding to the second exposure and the reference focal depth on the reference focal shift to determine a second adjustment coefficient corresponding to the second optical signal component, determining an adjusted first optical signal component based at least on a product of the first optical signal component and a corresponding second adjustment coefficient, and An adjusted second optical signal component is determined based at least on a product of the second optical signal component and a corresponding second adjustment coefficient.

8. The method according to claim 1, characterized in that Determining, based at least on the target optical signal, a simulated morphology of the photoresist after the photolithography process comprises: constructing a lithography simulation model for the photoresist based on the target optical signal and at least one kernel function related to the lithography process; and The photolithography simulation model is used to determine the simulated morphology of the photoresist after the photolithography process.

9. The method according to claim 8, characterized in that Constructing a lithography simulation model for the photoresist includes: Based on the first weight corresponding to the target optical signal and the second weight corresponding to each of the at least one kernel function, constructing the lithography simulation model by performing weighted fusion on the target optical signal and the at least one kernel function; and The first weight is greater than the second weight.

10. The method according to claim 8, characterized in that The at least one kernel function indicates at least one of the following: loading effects in the lithography process, and / or The physical effect of the predetermined shape in the lithography process.

11. The method according to claim 1, characterized in that: Determining a target optical signal related to the photolithography process includes: The adjusted plurality of optical signal components are summed to determine the target optical signal.

12. The method according to claim 1, characterized in that The target optical signal indicates at least one of the following: wavelength, Numerical aperture, Refractive index, Light source shape, and / or Light source parameters.

13. An electronic device, characterized in that: include: at least one processor; as well as At least one memory, the at least one memory is coupled to the at least one processor and stores instructions for execution by the at least one processor, the instructions causing the electronic device to perform the method according to any one of claims 1 to 12 when executed by the at least one processor.

14. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: The computer executable instructions are executable by a processor to implement the method according to any one of claims 1 to 12.

15. A computer program product comprising computer executable instructions, characterized in that: The computer executable instructions implement the method according to any one of claims 1 to 12 when executed by a processor.

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