Method, apparatus, and medium for lithography simulation

Abstract

Embodiments of the present disclosure relate to methods, devices, and media for lithography simulation. The methods proposed herein include: determining, from an initial optical signal, a plurality of optical signal components corresponding to multiple lithographies in a lithography process; 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 lithography process; and determining at least based on the target optical signal, a simulated topography of a photoresist after the lithography process.

Description

Technical Field

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

[0002] The lithography process is one of the key processes in semiconductor manufacturing. Currently, some semiconductor manufacturing processes require the use of relatively thick photoresist (e.g., photoresist with a thickness exceeding 5 μm). In the face of such thick photoresist, a lithography process with two or more exposures is required to ensure that the pattern can be accurately transferred onto the target substrate.

[0003] Lithography simulation aims to break through the limitations of hardware by improving software technologies such as resolution under the condition of unchanged hardware environment. However, traditional lithography simulation is difficult to capture the complex changes during multiple exposures, 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, there is provided a method for lithography simulation. The method includes: determining, from an initial optical signal, a plurality of optical signal components corresponding to multiple lithographies in a lithography process; 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 lithography process; and determining a simulated topography of the photoresist after the lithography process based at least on the target optical signal.

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

[0006] In a third aspect of the present disclosure, there is provided a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions that can be executed by a processor to implement the method of the first aspect.

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

[0008] It should be understood that the content described in this section is not intended to limit the key features or important features of the embodiments of the present disclosure, nor is it used 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] In conjunction with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent. In the drawings, the same or similar reference numerals denote the same or similar elements, where:

[0010] Figure 1 A schematic diagram showing an example environment in which the embodiments of the present disclosure can be implemented;

[0011] Figure 2 A flowchart showing an example process of a method for lithography simulation according to some embodiments of the present disclosure;

[0012] Figure 3 A schematic diagram showing an example of multiple exposures according to some embodiments of the present disclosure;

[0013] Figure 4 A block diagram of an electronic device in which one or more embodiments of the present disclosure can be implemented. Detailed Description of Specific Embodiments

[0014] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not used to limit the protection scope of the present disclosure.

[0015] It should be noted that the titles of any sections / subsections provided herein are not restrictive. Various embodiments are described throughout this document, and any type of embodiment can be included under any section / subsection. In addition, the embodiments described in any section / subsection can be combined with any other embodiments described in the same section / subsection and / or different sections / subsections in any manner.

[0016] In the description of the embodiments of the present disclosure, the term "including" and its like shall be understood as an open inclusion, that is, "including but not limited to". The term "based on" shall be understood as "at least partially based on". The term "one embodiment" or "the embodiment" shall be understood as "at least one embodiment". The term "some embodiments" shall be understood as "at least some embodiments". There may also be other explicit and implicit definitions hereinafter. The terms "first", "second", etc. may refer to different or the same objects. There may also be other explicit and implicit definitions hereinafter.

[0017] As briefly described above, some semiconductor manufacturing processes require the use of photoresist with a thickness exceeding 5 μm. Such semiconductor manufacturing processes include, but are not limited to, semiconductor manufacturing processes based on Complementary Metal-Oxide-Semiconductor Image Sensor (CIS), etc. Due to the increase in the thickness of the photoresist (the thickness of the photoresist in conventional semiconductor manufacturing processes is generally about 1 μm), it is difficult to accurately transfer patterns using the traditional single-exposure lithography process. Therefore, in actual operation, a lithography process with two or more exposures is usually required to ensure that the pattern can be accurately transferred onto the target substrate.

[0018] However, traditional lithography simulation is mainly designed and optimized based on the single-exposure lithography process. In the case of a lithography process with multiple exposures, traditional lithography simulation techniques are difficult to capture the complex changes during multiple exposures, resulting in a large deviation between the simulation results and the actual process.

[0019] In view of this, embodiments of the present disclosure provide a solution for lithography simulation. According to this solution, first, from the initial optical signal, multiple optical signal components corresponding to multiple lithography processes in the lithography process are determined. Then, based on the process parameters corresponding to each of the multiple exposures, each optical signal component among the multiple optical signal components is adjusted to determine the target optical signal related to the lithography process. Subsequently, at least based on the target optical signal, the simulated topography of the photoresist after the lithography process is determined.

[0020] As can be more clearly understood from the following description, the solution of the present disclosure decomposes 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 solution 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 highly matches the actual process conditions of each exposure. Next, the solution 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 during multiple exposures. And based on such an optical signal, the lithography simulation results can be made closer to the actual process of multiple exposures, thereby improving the reliability of lithography simulation.

[0021] In practical applications, especially in semiconductor manufacturing processes such as those based on CIS that require thick photoresist, this solution of optical signal deconstruction-compensation-reconstruction can effectively improve the accuracy of lithography simulation and improve production efficiency.

[0022] The following will further describe various exemplary implementations of this solution in detail with reference to the accompanying drawings.

[0023] Figure 1 FIG. shows a schematic diagram of an exemplary environment 100 in which various embodiments of the present disclosure can be implemented. Referring to Figure 1 , the exemplary environment 100 generally may include an electronic device 110, a target layout 120, a lithography simulation result 130, and a user 140.

[0024] The target layout 120 is used to indicate the pattern or structure to be formed on the photoresist during the lithography 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 lithography simulation result 140 for the photoresist. For example, the electronic device 110 receives a lithography simulation request from the user 140. The lithography simulation request may include process parameters related to the lithography process input by the user 140 and the target layout 120, etc. Then, based on the received process parameters and the target layout 120, the electronic device 110 uses, for example, a lithography simulation model to simulate the change of the photoresist during the lithography process, thereby obtaining the lithography simulation result 140. The lithography simulation result 140 may indicate the simulated topography of the photoresist after the lithography process. The lithography simulation model may include, but is not limited to, an Optical Proximity Correction (OPC) model, etc. The electronic device 110 may output the lithography simulation result 140 as a feedback to the lithography 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.

[0025] In the exemplary environment 100, the electronic device 110 can be any type of device with computing capabilities. Such a device may include, for example, a terminal device or a server device.

[0026] In some embodiments, the terminal device can be any type of mobile terminal, fixed terminal, or portable terminal, including mobile phones, desktop computers, laptop computers, notebook computers, netbook computers, tablet computers, media computers, multimedia tablets, Personal Communication System (PCS) devices, personal navigation devices, Personal Digital Assistant (PDA), audio / video players, digital cameras / camcorders, positioning devices, television receivers, radio broadcast receivers, e-book devices, game devices, or any combination of the foregoing, including accessories and peripherals of these devices or any combination thereof.

[0027] In some embodiments, the server device can be an independent physical server, a server cluster or a 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 delivery networks, and big data and artificial intelligence platforms. The server device can, for example, include a computing system / server, such as a mainframe, an edge computing node, a computing device in a cloud environment, and so on.

[0028] It should be understood that the structures and functions of the various elements in environment 100 are described only for exemplary purposes, without implying any limitation on the scope of the present disclosure.

[0029] Figure 2 A flowchart of an example process 200 for a lithography simulation method according to some embodiments of the present disclosure is shown. Process 200 can be implemented at the electronic device 110.

[0030] Referring to Figure 2 , at block 210, the electronic device 110 determines a plurality of optical signal components corresponding to multiple lithographies in the lithography process from an initial optical signal.

[0031] The lithography process can refer to a process of transferring the pattern on a mask plate to a photoresist using an optical system. The lithography process includes, but is not limited to, steps such as coating, exposure, development, etching, and stripping. In the exposure step, the light emitted by the light source is projected onto the substrate coated with photoresist through the mask plate. After the development step, a pattern corresponding to the mask plate will be formed on the photoresist on the substrate. For thick photoresists, in order to accurately form a pattern thereon, a lithography process with multiple exposures can be used. By multiple exposures, the limitation of single exposure on accuracy can be broken through, thereby achieving a better pattern transfer effect.

[0032] The photoresist can also be referred to as a photoresist, which is a corrosion-resistant thin film material. In the lithography process, the photoresist is used as an anti-corrosion coating to provide necessary protection for the surface processing of semiconductor materials. The main components of the photoresist include polymers, photoinitiators, solvents, etc., and these components will undergo chemical changes under the irradiation of light, thereby changing the solubility of the photoresist.

[0033] The photoresist can 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 in the 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 photoresist in the conventional process is generally about 1 μm). Such a thick photoresist can, for example, provide better pattern transfer accuracy and a wider process window.

[0034] 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 light (UV) or extreme ultraviolet light (EUV), etc.

[0035] For the convenience of discussion, the initial optical signal and the target optical signal mentioned below in this article are also individually or collectively referred to as optical signals. The optical signal can refer to the characteristic representation of at least one optical parameter of the optical system. In some embodiments, the optical signal can indicate at least one of the following: the wavelength, numerical aperture, refractive index, and / or light source shape of the optical system, etc. In some embodiments, the optical signal can be represented by a kernel function, etc.

[0036] In some embodiments, the electronic device 110 can split the initial optical signal according to the number of exposures in the lithography process, so as to obtain the optical signal components corresponding to each exposure. In some embodiments, the optical signal components can indicate the wavelength, numerical aperture, refractive index, and / or light source shape, etc. involved in the corresponding exposure.

[0037] It should be noted that the above descriptions of the optical signal and the optical signal components are only examples, which do not constitute a limitation on the embodiments of the present disclosure. According to actual needs, the optical signal and the optical signal components can also indicate more content. For example, the optical signal and the optical signal components can also indicate the inner diameter and / or outer diameter of the light source, etc. The optical signal and the optical signal components can also be represented in other forms besides the kernel function. The embodiments of the present disclosure will not list them one by one here.

[0038] In block 220, the electronic device 110 adjusts each of the optical signal components among the multiple optical signal components based on the process parameters corresponding to the multiple exposures, so as to determine the target optical signal related to the lithography process.

[0039] The process parameters can refer to a series of specific values or conditions used to guide the exposure process in the lithography process. As an example, the process parameters include but are not limited to depth of focus, focus offset, and / or exposure energy, etc. It should be noted that the above descriptions of the process parameters are only examples, which do not constitute a limitation on the embodiments of the present disclosure. According to actual needs, the process parameters can also include more content, and the embodiments of the present disclosure will not list them one by one here.

[0040] 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 depth of focus, focus offset, exposure energy, etc. involved in the given exposure, so as to compensate the given optical signal component to make it more matched with the actual process conditions of the corresponding exposure.

[0041] In some embodiments, the process parameters corresponding to each of the multiple exposures at least include exposure energy. The electronic device 110 adjusts each optical signal component among the multiple optical signal components at least based on the relative relationship between the exposure energy corresponding to each of the multiple exposures and the reference exposure energy.

[0042] The exposure energy may refer to the energy of light irradiated on a unit area of photoresist. In some embodiments, the reference exposure energy may be given by the user or determined based on the multiple exposure energies corresponding to the multiple exposures. For each exposure among 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 suitable comparison method. For example, the electronic device 110 may determine the relative relationship between the exposure energy and the reference exposure energy based on the ratio, difference, or more complex mathematical relationship between the exposure energy and the reference exposure energy.

[0043] 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 the optical signal (such as the target optical signal), so that the reconstructed optical signal can better adapt to the differences in exposure energy among the multiple exposures. As an example, for a certain exposure among the multiple exposures, if the relative relationship between the corresponding exposure energy and the reference exposure energy indicates that the exposure energy is at a relatively high energy level among the multiple exposures, then the electronic device 110 may make the optical signal component corresponding to the exposure have a larger weight when reconstructing the optical signal. On the contrary, if the relative relationship between the corresponding exposure energy and the reference exposure energy indicates that the exposure energy is at a relatively low energy level among the multiple exposures, then the electronic device 110 may make the optical signal component corresponding to the exposure have a smaller weight when reconstructing the optical signal.

[0044] In some embodiments, the reference exposure energy is determined based on the sum of the exposure energies corresponding to each of the multiple exposures. In this way, it helps 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.

[0045] It should be noted that the above method for determining the reference exposure energy is only an exemplary illustration. According to actual needs, the reference exposure energy can also be determined in more ways. For example, the reference exposure energy can also be determined based on the central value or the optimal value of the exposure energies corresponding to multiple exposures, etc. The embodiments of the present disclosure will not list them one by one here.

[0046] In some embodiments, the multiple exposures include a first exposure and a second exposure following 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 the electronic device 110 can adjust each optical signal component in the following manner. First, the electronic device 110 determines a 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 a 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.

[0047] The first exposure and the second exposure can be any one of the multiple exposures. Assume that the first exposure is the first exposure among the multiple exposures and the second exposure is the second exposure among the multiple exposures. The first optical signal component corresponding to the first exposure is , and the second optical signal component corresponding to the second exposure is . The process by which the electronic device 110 adjusts the first optical signal component based on the first adjustment coefficient corresponding to it can be represented by formula (1): ; (1)

[0048] ; (1)

[0049] where is the first adjustment coefficient corresponding to the first optical signal component , is the exposure energy corresponding to the first exposure, D2 is the exposure energy corresponding to the second exposure, is the optical signal component of the first optical signal component after being adjusted by the first adjustment coefficient .

[0050] The electronic device 110 adjusts the second optical signal component based on the first adjustment coefficient corresponding to it, for the second optical signal component The process of making adjustments can be represented by Equation (2):

[0051] ; (2)

[0052] where is the first adjustment coefficient corresponding to the second optical signal component and is the optical signal component of the second optical signal component after being adjusted by the first adjustment coefficient .

[0053] In this way, the electronic device 110 can quickly and accurately adjust each optical signal component so that each optical signal component adapts to the actual exposure energy corresponding to the corresponding exposure.

[0054] It should be noted that the formulas and parameters related to the adjustment of the optical signal components above are only for illustrative purposes and do not constitute a limitation on the embodiments of the present disclosure. According to actual needs, other formulas and parameters can also be used to adjust the optical signal components.

[0055] In some embodiments, the process parameters corresponding to each of the multiple exposures at least include focus offset and depth of focus. The electronic device 110 adjusts each of the optical signal components among the multiple optical signal components at least based on the difference between the depth of focus corresponding to each exposure in the multiple exposures and the reference depth of focus and the reference focus offset.

[0056] The depth of focus may refer to the axial range in the imaging space where the optical system maintains clear imaging. When the exposure position deviates from the ideal focal plane, a defocus effect is introduced, and its degree can be represented by the focus offset, which can be approximated as the difference between the depth of focus and the ideal focal plane.

[0057] As an example, the electronic device 110 can determine the difference between the depth of focus corresponding to each exposure and the reference depth of focus through any suitable comparison method. For example, the electronic device 110 can determine the difference between the two through the difference, ratio, or more complex mathematical relationship between the depth of focus corresponding to a given exposure and the reference depth of focus.

[0058] As an example, the reference depth of focus can be given by the user or determined based on the depth of focus corresponding to the multiple exposures. Similarly, the reference focus offset can be given by the user or determined based on the focus offset corresponding to the multiple exposures.

[0059] Figure 3 shows a schematic diagram of an example 300 of multiple exposures according to some embodiments of the present disclosure. Referring to Figure 3, a photoresist 303 is formed on a substrate 304. Assume that multiple exposures in a lithography process include a first exposure 301 and a second exposure 302. At the same position of the photoresist 303, for an ideal focal plane F0, the depth of focus corresponding to the first exposure is F1, and the depth of focus 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 depth of focus (distance from the same ideal focal plane) corresponding to the exposure also gradually increases. The electronic device 110 can determine the change in the depth of focus for each exposure based on the difference between the depth of focus corresponding to each exposure and a reference depth of focus (such as the depth of focus 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. Subsequently, the electronic device 110 can adjust the optical signal component corresponding to each exposure based on the actual focus offset corresponding to each exposure.

[0060] As an example, the actual focus offset can be used to adjust the proportion of the corresponding optical signal component when reconstructing an optical signal (such as a target optical signal), so that the reconstructed optical signal can better adapt to the differences in focus offset during multiple exposures. As an example, for a certain exposure in multiple exposures (such as the first exposure 301), if the actual focus offset corresponding to it is small, the electronic device 110 can make the optical signal component corresponding to this exposure have a small proportion when reconstructing the optical signal. Conversely, for a certain exposure in multiple exposures (such as the second exposure 302), if the actual focus offset corresponding to it is large, the electronic device 110 can make the optical signal component corresponding to this exposure have a large proportion when reconstructing the optical signal. In this way, the electronic device 110 can make each optical signal component match the actual focus offset of the corresponding exposure.

[0061] In some embodiments, the reference depth of focus is determined based on the depth of focus corresponding to the first exposure in multiple exposures. Alternatively or additionally, the reference focus offset is determined based on the focus offset corresponding to the first exposure in multiple exposures. In this way, the electronic device 110 can minimize the introduction of parameters, thereby simplifying the calculation process.

[0062] In some embodiments, the multiple exposures include a first exposure and a second exposure following 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. The electronic device 110 can adjust each optical signal component in the following manner. First, the electronic device 110 superimposes the difference between the depth of focus corresponding to the first exposure and the reference depth of focus on the reference focus offset to determine a second adjustment coefficient corresponding to the first optical signal component. And the electronic device 110 superimposes the difference between the depth of focus corresponding to the second exposure and the reference depth of focus on the reference focus offset to determine a second adjustment coefficient corresponding to the second optical signal component. Subsequently, 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. 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 second adjustment coefficient.

[0063] As an example, continuing to refer to Figure 3 , assume 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 depth of focus is the depth of focus F1 corresponding to the first exposure 301. The process by which the electronic device 110 adjusts the first optical signal component corresponding to the second adjustment coefficient can be expressed by Equation (3): ; (3)

[0064] ; (3)

[0065] where is the second adjustment coefficient corresponding to the first optical signal component , is the optical signal component after the first optical signal component is adjusted by the second adjustment coefficient , DE1 = defocus , or DE1 can also take other values.

[0066] The process by which the electronic device 110 adjusts the second optical signal component corresponding to the second adjustment coefficient can be expressed by Equation (4): ; (4)

[0067] ; (4)

[0068] where is the second adjustment coefficient corresponding to the second optical signal component , as the second optical signal component adjusted by a second adjustment coefficient The adjusted optical signal component, DE2 = , or DE2 can also take other values.

[0069] In this way, the electronic device 110 can quickly and accurately adjust each optical signal component so that each optical signal component adapts to the actual focus shift of the corresponding exposure.

[0070] It should be noted that the formulas and parameters related to the adjustment of the optical signal component above are only for illustrative purposes, which does not constitute a limitation on the embodiments of the present disclosure. According to actual needs, other formulas and parameters can also be used to adjust the optical signal component.

[0071] In some embodiments, the electronic device 110 can adjust multiple optical signal components through formula (1) and formula (2). Alternatively, the electronic device 110 can adjust multiple optical signal components through formula (3) and formula (4). Alternatively, the electronic device 110 can adjust multiple optical signal components through formula (1) to formula (4). Specifically, it can be determined according to actual needs, and the embodiments of the present disclosure do not limit this.

[0072] 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. For details not described here, reference can be made to the description of the initial optical signal in the previous text to determine, so the embodiments of the present disclosure will not elaborate on this anymore.

[0073] In some embodiments, the electronic device 110 determines the target optical signal by summing up the adjusted multiple optical signal components.

[0074] In some embodiments, the electronic device 110 can determine the target optical signal by directly superimposing the adjusted multiple optical signal components. Alternatively, the electronic device 110 can also determine the target optical signal by performing a weighted sum of the adjusted multiple optical signal components. Assuming that the electronic device 110 adjusts multiple optical signal components through formula (1) to formula (4), the process for the electronic device 110 to determine the target optical signal can be represented by formula (5):

[0075] . (5)

[0076] In some embodiments, to ensure the accuracy of the target optical signal, the electronic device 110 can perform a calibration operation on at least one process parameter involved in the calculation of the target optical signal.

[0077] In some embodiments, the exposure energy and depth of focus corresponding to each exposure are measurable process parameters. That is to say, these process parameters can be accurately determined by appropriate measurement methods. In this case, referring to Equation (5), during the calculation of the target optical signal only the reference focus offset needs to be calibrated. As an example, in some embodiments, the initial value of the reference focus offset can be determined based on the depth of focus corresponding to the first exposure among multiple exposures. After determining the initial value of the reference focus offset, the electronic device 110 can perform a calibration operation on this initial value. Specifically, the electronic device 110, with the exposure energies D1, D2, optical signal components , and the depth of focus remaining unchanged, uses a specific algorithm or program to gradually adjust this 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, thus completing the calibration operation of the reference focus offset.

[0078] In this way, the embodiments of the present disclosure minimize the introduction of process parameters that need to be calibrated while ensuring the accuracy of the optical signal.

[0079] Once the target optical signal is determined, at block 230, the electronic device 110 determines the simulated topography of the photoresist 303 after the lithography process based at least on the target optical signal.

[0080] In some embodiments, the electronic device 110 can construct a lithography simulation model based at least on the target optical signal. Then, the electronic device 110 uses the lithography simulation model to determine the simulated topography of the photoresist 303 after the lithography process. As an example, the lithography simulation model includes, but is not limited to, the OPC model, etc. The OPC model aims to solve the problem of the mutual influence between adjacent patterns caused by effects such as light diffraction and interference during the lithography 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 at the same time, combine the analysis and correction methods of the OPC model for the proximity effect to correct the reaction of the photoresist 303.

[0081] After the calculation and analysis of the lithography simulation model, the electronic device 110 finally determines the simulated topography of the photoresist 303 after the lithography process. The simulated topography can be presented in various forms, such as a three-dimensional graph, a contour map, or a data table. By comparing the simulated topography with the target topography of the design requirements, the user 140 can determine whether the current lithography process parameters are reasonable, and then analyze whether adjustments and optimizations are needed.

[0082] In some embodiments, the electronic device 110 constructs a lithography simulation model for the photoresist 303 based on the target optical signal and at least one kernel function related to the lithography process. Subsequently, the electronic device 110 uses the lithography simulation model to determine the simulated topography of the photoresist 303 after the lithography process.

[0083] In some embodiments, at least one kernel function indicates the influence of various physical phenomena and effects in the lithography process on the topography 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.

[0084] In some embodiments, at least one kernel function indicates at least one of the following: the loading effect in the lithography process, and / or the physical effect of a predetermined shape in the lithography process. In this way, the electronic device 110 can maximize the accuracy of lithography simulation with fewer kernel functions introduced.

[0085] 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 the first weight corresponding to the target optical signal and the second weight corresponding to each of the at least one kernel function. The first weight is greater than the second weight.

[0086] In the embodiments 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 scheme, thereby greatly improving the efficiency of lithography simulation.

[0087] As an example, the lithography simulation model can be represented by formula (6):

[0088] simulation_signal = [C1*Optical + C 21 *Kernel1+ C 22 *Kernel2+ … + C 2m *Kernel m @ layout;(6)

[0089] Among them, C1 represents the first weight, Kernel1, Kernel2, ……, Kernel m represents m kernel functions, C 21 , C 22 , ……, C 2m represents 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 multiplication 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, and the sum of C 21 , C 22 , ……, C 2m can be "1".

[0090] It should be noted that, according to actual needs, at least one kernel function can further include other kernel functions in addition to the above-mentioned kernel functions, so as to further improve the accuracy of lithography simulation. In addition, in some applications, the kernel function can also be not used to maximize the simulation speed of the lithography simulation model.

[0091] It can be more clearly understood through the foregoing description that the embodiments of the present disclosure perform splitting-compensation-reconstruction on 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 them, 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 slowdown of the simulation speed of the lithography simulation model can be avoided, and on the other hand, the risk of overfitting can be reduced.

[0092] Figure 4 shows a block diagram of an electronic device 400 in which one or more embodiments of the present disclosure can be implemented. The electronic device 400 can be used, for example, to implement the electronic device 110 as shown in Figure 1 . It should be understood that Figure 4 the electronic device 400 shown is merely exemplary and should not constitute any limitation to the functions and scopes of the embodiments described herein.

[0093] Referring to Figure 4, the electronic device 400 is in the form of a general-purpose 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 a physical or virtual processor and is capable of performing various processes according to programs stored in the memory 420. In a multi-processor system, multiple processors execute computer-executable instructions in parallel to improve the parallel processing ability of the electronic device 400.

[0094] The electronic device 400 generally includes multiple computer storage media. Such media may 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 may be volatile memory (such as registers, caches, random access memory (RAM)), non-volatile memory (such as read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory), or some combination thereof. The storage device 430 may be removable or non-removable media and may include machine-readable media, such as a flash drive, a magnetic disk, or any other media that can be used to store information and / or data and can be accessed within the electronic device 400.

[0095] The electronic device 400 may further include additional removable / non-removable, volatile / non-volatile storage media. Although not shown in Figure 4 , a disk drive for reading from or writing to a removable, non-volatile magnetic disk (such as a "floppy disk") and an optical disk drive for reading from or writing to a removable, non-volatile optical disk may be provided. In these cases, each drive may be connected to a 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 the various embodiments of the present disclosure.

[0096] The communication unit 440 enables communication with other electronic devices through a communication medium. Additionally, the functions of the components of the electronic device 400 may be implemented by a single computing cluster or multiple computer machines that are capable of communicating through a communication connection. Thus, the electronic device 400 may operate in a networked environment using a logical connection with one or more other servers, network personal computers (PCs), or another network node.

[0097] The input device 450 can be one or more input devices, such as a mouse, a keyboard, a trackball, etc. The output device 460 can be one or more output devices, such as a display, a speaker, a printer, etc. The electronic device 400 can also communicate with one or more external devices (not shown) as needed through the communication unit 440. The external devices such as a storage device, a display device, etc., communicate with one or more devices that enable a user to interact with the electronic device 400, or communicate with any device (e.g., a network card, a modem, etc.) that enables the electronic device 400 to communicate with one or more other electronic devices. Such communication can be performed via an input / output (I / O) interface (not shown).

[0098] According to an exemplary implementation of the present disclosure, there is provided a computer-readable storage medium having computer-executable instructions stored thereon, 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, there is also provided a computer program product, the computer program product being tangibly stored on a non-transitory computer-readable medium and including computer-executable instructions, and the computer-executable instructions being executed by a processor to implement the method described above.

[0099] Aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of methods, apparatuses, devices, and computer program products implemented according to the present disclosure. It should be understood that each block of the flowcharts and / or block diagrams, and the combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer-readable program instructions.

[0100] 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 apparatus to produce a machine, such that the instructions, when executed by the processor of the computer or other programmable data processing apparatus, create a means for implementing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. These computer-readable program instructions can also be stored in a computer-readable storage medium, which instructions cause a computer, a programmable data processing apparatus, and / or other devices to operate in a particular manner, so that the computer-readable medium storing the instructions includes a manufacture including instructions for implementing various aspects of the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams.

[0101] The computer-readable program instructions can be loaded onto a computer, other programmable data processing apparatus, or other device, such 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 / acts specified in one or more blocks of the flowcharts and / or block diagrams.

[0102] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various implementations of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur in an order different from that noted in the accompanying drawings. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0103] The various implementations of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art in the field of the present technology 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, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art in the field of the present technology to understand the various implementation manners disclosed herein.

Claims

1. A method for lithography simulation, characterized in that, Including: Determining, from an initial optical signal, a plurality of optical signal components corresponding to multiple exposures in a lithography process, where the initial optical signal is a characteristic representation of at least one optical parameter of an optical system; Adjusting each of the plurality of optical signal components based on process parameters corresponding to the multiple exposures respectively to determine a target optical signal related to the lithography process; And Determining at least based on the target optical signal a simulated topography of a photoresist after the lithography process.

2. The method according to claim 1, wherein The process parameters corresponding to the multiple exposures respectively include at least exposure energy, and where adjusting each of the plurality of optical signal components includes: Adjusting each of the plurality of optical signal components at least based on a relative relationship between the exposure energy corresponding to each of the multiple exposures and a reference exposure energy.

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

4. The method according to claim 2 or 3, characterized in that, The multiple exposures include a first exposure and a second exposure 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 where adjusting each of the plurality of optical signal components includes: Determining a first adjustment coefficient corresponding to the first optical signal component based on a ratio of the exposure energy corresponding to the first exposure to the reference exposure energy, Determining a first adjustment coefficient corresponding to the second optical signal component based on a ratio of the exposure energy corresponding to the second exposure to the reference exposure energy, Determining the adjusted first optical signal component at least based on a product of the first optical signal component and the corresponding first adjustment coefficient, and Determining the adjusted second optical signal component at least based on a product of the second optical signal component and the corresponding first adjustment coefficient.

5. The method according to claim 1, wherein The process parameters corresponding to the multiple exposures respectively include at least depth of focus, and where adjusting each of the plurality of optical signal components includes: Adjusting each of the plurality of optical signal components at least based on a difference between the depth of focus corresponding to each exposure in the multiple exposures and a reference depth of focus and a reference focus shift.

6. The method according to claim 5, wherein The reference depth of focus is determined based on the depth of focus corresponding to the first exposure in the multiple exposures, and / or The reference focus shift is determined based on the focus shift corresponding to the 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 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 where adjusting each of the plurality of optical signal components includes: Superposing a difference between the depth of focus corresponding to the first exposure and the reference depth of focus on the reference focus shift to determine a second adjustment coefficient corresponding to the first optical signal component, Superimpose the difference between the depth of focus corresponding to the second exposure and the reference depth of focus on the reference focus offset to determine the second adjustment coefficient corresponding to the second optical signal component, Determine the adjusted first optical signal component based at least on the product of the first optical signal component and the corresponding second adjustment coefficient, and Determine the adjusted second optical signal component based at least on the product of the second optical signal component and the corresponding second adjustment coefficient.

8. The method according to claim 1, characterized in that Determine the simulated topography of the photoresist after the lithography process based at least on the target optical signal, including: Construct 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 Use the lithography simulation model to determine the simulated topography of the photoresist after the lithography process.

9. The method according to claim 8, wherein Constructing a lithography simulation model for the photoresist includes: Construct the lithography simulation model by performing weighted fusion on the target optical signal and the at least one kernel function based on the first weight corresponding to the target optical signal and the second weights corresponding to the at least one kernel function respectively; and Wherein the first weight is greater than the second weight.

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

11. The method according to claim 1, characterized in that, Determine the target optical signal related to the lithography process, including: Sum the adjusted multiple optical signal components 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, Comprising: At least one processor; And At least one memory, the at least one memory being coupled to the at least one processor and storing instructions for execution by the at least one processor, the instructions when executed by the at least one processor causing the electronic device to perform the method according to any one of claims 1 to 12.

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

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