A digital lithography simulation method and related device

Abstract

The present application provides a digital lithography simulation method and related devices, which obtain the design file and array diagram of a digital micromirror array; the digital micromirror array includes multiple micromirrors; based on the design file and array diagram, a grayscale image of the digital micromirror array is generated; based on the optical system information and the grayscale image, the initial electromagnetic field distribution of light after passing through the optical system is calculated; based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated; the photoresist latent image includes the three-dimensional light intensity distribution of light in the photoresist structure; and the residual photoresist profile is determined based on the photoresist latent image and the light intensity threshold. Through the above simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation results are relatively accurate. Manual testing is not required, which saves a lot of manpower and material resources, improves efficiency, and improves the production efficiency of digital mask grayscale lithography.

Description

Technical Field

[0001] The present application relates to the field of photolithography, and in particular to a digital photolithography simulation method and related devices. Background Art

[0002] Digital mask lithography (abbreviated as digital lithography) is a new technology derived from traditional optical lithography. Its exposure and imaging method is basically similar to traditional projection lithography. The main principle is to input the required lithography pattern into the digital micromirror array (DMD) chip through computer software, and change the rotation angle of the DMD chip micromirror according to the distribution of black and white pixels in the lithography pattern. A collimated light source is irradiated onto the DMD chip to form a light image consistent with the required pattern, which is projected onto the surface of the photoresist. By controlling the movement of the sample stage, large-area microstructure preparation can be achieved. In addition, grayscale lithography can also be achieved more ideally by modulating the grayscale.

[0003] During the manufacturing process, similar to the mask design in traditional photolithography, the grayscale distribution of the digital micromirror array designed in this digital mask system also requires the support and modification of experimental results. The initial design is not necessarily completely reasonable, but verifying it through experiments requires a lot of manpower and material resources. Therefore, providing a suitable digital photolithography simulation method has become a technical problem that urgently needs to be solved. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a digital lithography simulation method and related devices, which do not require manual testing, save a lot of manpower and material resources, speed up the process, and improve the production efficiency of digital mask grayscale lithography. The specific scheme is as follows:

[0005] In one aspect, the present application provides a digital lithography simulation method, comprising:

[0006] Obtaining a design file and an array diagram of a digital micromirror array; the digital micromirror array includes a plurality of micromirrors; the design file includes the position, switch state, and on-time of each of the micromirrors, and the array diagram includes the size and position of each of the micromirrors;

[0007] Based on the design file and the array diagram, a grayscale image of the digital micromirror array is generated; the grayscale image includes grayscale information of each micromirror;

[0008] Calculating the initial electromagnetic field distribution of the light after it passes through the optical system based on the optical system information and the grayscale image;

[0009] Based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure;

[0010] A residual photoresist profile is determined based on the photoresist latent image and a light intensity threshold.

[0011] Specifically, the calculating and obtaining the photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure includes:

[0012] Based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated by a transfer matrix method.

[0013] Specifically, the calculating and obtaining the photoresist latent image by using a transfer matrix method based on the initial electromagnetic field distribution and the photoresist structure includes:

[0014] determining at least one first transmission matrix in an air environment;

[0015] determining at least one second transmission matrix in the photoresist structure based on parameters of the photoresist structure, wherein the parameters of the photoresist structure include thickness and refractive index;

[0016] The photoresist latent image is calculated based on the initial electromagnetic field distribution, the first transmission matrix, and the second transmission matrix.

[0017] Specifically, the calculating, based on the optical system information and the grayscale image, the initial electromagnetic field distribution of the light after passing through the optical system includes:

[0018] Based on the optical system information and the grayscale image, the initial electromagnetic field distribution of the light after passing through the optical system is calculated using a fast optical imaging model.

[0019] Specifically, the fast optical imaging model is constructed based on fast Fourier transform.

[0020] Specifically, determining the residual photoresist profile based on the photoresist latent image and the light intensity threshold includes:

[0021] Determining a two-dimensional light intensity distribution at a cross section of the photoresist structure from the photoresist latent image; the two-dimensional light intensity distribution includes light intensities corresponding to respective positions;

[0022] For each position, if the light intensity corresponding to the position is greater than the light intensity threshold, the position is determined to be located in a region outside the residual photoresist profile; otherwise, the position is determined to be located in a region within the residual photoresist profile;

[0023] Based on all positions of the region within the residual photoresist profile, their boundary lines are taken as the residual photoresist profile.

[0024] Specifically, the method further includes:

[0025] Fitting the residual photoresist profile to obtain a fitting profile;

[0026] The fitting profile is compared with a preset profile to determine whether the design file meets the preset requirements.

[0027] In another aspect, the present application further provides a digital lithography simulation device, comprising:

[0028] an acquisition unit, configured to acquire a design file and an array diagram of a digital micromirror array; the digital micromirror array comprising a plurality of micromirrors; the design file including the position, switch state, and on-time of each micromirror; and the array diagram including the size and position of each micromirror;

[0029] A generating unit, configured to generate a grayscale image of the digital micromirror array based on the design file and the array image; the grayscale image includes grayscale information of each of the micromirrors;

[0030] A first calculation unit is used to calculate the initial electromagnetic field distribution of the light after it passes through the optical system based on the optical system information and the grayscale image;

[0031] A second calculation unit is configured to calculate a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure;

[0032] A determining unit is configured to determine a residual photoresist profile based on the photoresist latent image and a light intensity threshold.

[0033] In another aspect, an embodiment of the present application provides a computer device, comprising a processor and a memory:

[0034] The memory is used to store program code and transmit the program code to the processor;

[0035] The processor is configured to execute the method described above according to the instructions in the program code.

[0036] On the other hand, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method described in the above aspects.

[0037] The embodiment of the present application provides a digital lithography simulation method and related apparatus, which obtains a design file and an array diagram of a digital micromirror array; the digital micromirror array includes a plurality of micromirrors; the design file includes the position, switch state, and on-time of each micromirror, and the array diagram includes the size and position of each micromirror; based on the design file and the array diagram, a grayscale image of the digital micromirror array is generated; the grayscale image includes grayscale information of each micromirror; based on the optical system information and the grayscale image, the initial electromagnetic field distribution of light after passing through the optical system is calculated; based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure; and based on the photoresist latent image and the light intensity threshold, a residual photoresist profile of the photoresist structure is determined. In the present application, through the above-mentioned simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation result is relatively accurate, without the need for manual testing, saving a lot of manpower and material resources, and improving efficiency, which can accelerate the modification process of the design file, thereby etching a device structure that meets the requirements, accelerating the process, and improving the production efficiency of digital mask grayscale lithography. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A schematic diagram showing a comparison between digital lithography and traditional optical lithography in related art is shown;

[0040] Figure 2 A schematic diagram of a digital lithography simulation method provided in an embodiment of the present application is shown;

[0041] Figure 3 A schematic structural diagram of a single micromirror provided in an embodiment of the present application is shown;

[0042] Figure 4 A schematic structural diagram of a digital micromirror array provided in an embodiment of the present application is shown;

[0043] Figure 5 A schematic diagram of a grayscale image of a digital micromirror array provided in an embodiment of the present application is shown;

[0044] Figure 6 A schematic diagram showing the principle of a transmission matrix method provided in an embodiment of the present application is shown;

[0045] Figure 7A schematic diagram of a two-dimensional light intensity distribution provided by an embodiment of the present application is shown;

[0046] Figure 8 A schematic diagram of a residual photoresist profile provided in an embodiment of the present application is shown;

[0047] Figure 9 A schematic diagram of a fitting profile provided in an embodiment of the present application is shown;

[0048] Figure 10 A schematic structural diagram of a digital lithography simulation device provided in an embodiment of the present application;

[0049] Figure 11 A structural diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0051] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0052] Secondly, this application is described in detail with reference to schematic diagrams. When describing the embodiments of this application, for ease of explanation, cross-sectional views of device structures may be partially enlarged and not to scale. Furthermore, these schematic diagrams are merely illustrative and should not limit the scope of protection of this application. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0053] As described in the background technology, digital lithography is similar to the exposure imaging method of traditional optical lithography. Figure 1 As shown, it is a schematic diagram comparing digital lithography and traditional optical lithography in related technologies. In the traditional optical lithography system, there are a light source, an illumination system, a mask, a projection system, a photoresist film and a product substrate. Replacing the mask with a DMD chip is a digital lithography system.

[0054] A digital micromirror array (DMA) is a flippable array of micromirrors whose grayscale can be modulated by controlling the flipping time. As a pattern generator, it is often used in micro- and nanofabrication, and is also known as a digital mask. Its flexibility allows it to generate virtually any desired two-dimensional or even three-dimensional pattern, significantly reducing costs by replacing traditional reticles. Because it can produce images of varying grayscale by controlling the micromirror flipping time, DMAs are often used in grayscale lithography. The ability to freely adjust patterns and grayscale modulation has earned it a prominent position in this field.

[0055] During the manufacturing process, similar to the mask design in traditional photolithography, the grayscale distribution of the digital micromirror array designed in this digital mask system also requires the support and modification of experimental results. The initial design is not necessarily completely reasonable, but verifying it through experiments requires a lot of manpower and material resources.

[0056] Based on the above technical problems, the embodiments of the present application provide a digital lithography simulation method and related devices. Through the simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation results are relatively accurate. There is no need for manual testing, which saves a lot of manpower and material resources and improves efficiency. It can speed up the modification process of the design file, thereby etching out a device structure that meets the requirements, speeding up the process process, and improving the production efficiency of digital mask grayscale lithography.

[0057] For ease of understanding, a digital lithography simulation method and related devices provided in an embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0058] refer to Figure 2 FIG. 1 is a flow chart of a digital lithography simulation method provided in an embodiment of the present application. The method may include the following steps.

[0059] S101, obtaining a design file and an array diagram of a digital micromirror array.

[0060] A digital micromirror array (DMAA) can include multiple micromirrors and is an array structure composed of a large number of micromirrors. In digital lithography, a DMA can be used as a mask. Design files for DMAs are available. The format of these files is not limited here and can include the position, on / off state, and on-time of each micromirror.

[0061] In other words, the design file can reflect the position of each micromirror, whether each micromirror is open or closed, and the duration of each micromirror's opening. In actual applications, when the micromirror is in the open state, the micromirror reflects light to the main optical axis to form an image, and when the micromirror is in the closed state, the micromirror does not form an image. By controlling the micromirror to open or close, a binary image can be formed, that is, only including 0 and 1. As an example, the micromirror opening can correspond to 1, and the micromirror closing can correspond to 0.

[0062] refer to Figure 3 Figure 1 shows a schematic diagram of the structure of a single micromirror according to an embodiment of the present invention. The white area in the figure represents the micromirror surface, which can be controlled to be on or off. Furthermore, by controlling the duration of the micromirror's on-state, images with varying grayscale levels can be generated. For example, the grayscale levels can be set to 256 or 512, thereby enabling grayscale lithography.

[0063] Specifically, an array diagram of a digital micromirror array can be obtained, in which the size and position of each micromirror can be included. Figure 4 , which is a structural diagram of a digital micromirror array provided in an embodiment of the present application, including a large number of micromirrors.

[0064] S102 , generating a grayscale image of the digital micromirror array based on the design file and the array image.

[0065] Specifically, the design file can reflect whether a certain position is allowed to transmit light and the time for transmitting light. The array diagram can reflect the position and size of each micromirror. Therefore, based on the design file and the array diagram, a grayscale image of the digital micromirror array can be generated.

[0066] The grayscale image may include the grayscale information of each micromirror, that is, the grayscale value corresponding to the area where each micromirror is located. For example, if the micromirror is turned off, its grayscale information is 255. If the micromirror is turned on for a long enough time, the grayscale information may be 0. If the micromirror is turned on for a short time, the grayscale information may be 125, for example.

[0067] Grayscale images can be used as masks. Because grayscale images can represent different grayscale values ​​at different locations, allowing light with different intensities to pass through at different locations, they can replace masks used in traditional optical lithography. In practical applications, a simulation model of a digital lithography system can be established to perform the simulation calculations described in this application.

[0068] refer to Figure 5 As shown, it is a schematic diagram of a grayscale image of a digital micromirror array provided in an embodiment of the present application. In the digital micromirror array, the light intensity in the middle is weaker, and the light intensity around is stronger. The light intensity gradually increases from the middle to the surrounding areas, which can be used to prepare spherical mirror devices.

[0069] S103 , calculating the initial electromagnetic field distribution of the light after it passes through the optical system based on the optical system information and the grayscale image.

[0070] Specifically, the optical system information is parameter information of the optical system. The optical system may include a light source, an illumination system, and a projection system. The optical system information may include, for example, the wavelength of the light source, the parameters of the lens, etc. Using the optical system information and the grayscale image, the electromagnetic field distribution of the light emitted by the light source after passing through the illumination system, the digital micromirror array, and the projection system can be calculated. This electromagnetic field distribution can be recorded as the initial electromagnetic field distribution. The initial electromagnetic field distribution may be the electromagnetic field distribution on the focal plane of the projection system. The initial electromagnetic field distribution may include the initial electric field intensity E0 and the initial magnetic field intensity H0. In short, the initial electromagnetic field distribution can reflect the distribution of light after passing through the optical system.

[0071] In addition, by calculating the initial electromagnetic field distribution, we can obtain the two-dimensional light intensity distribution after the light passes through the optical system. This two-dimensional light intensity distribution is the energy distribution on the focal plane of the projection system, which can be used to verify the subsequent three-dimensional light intensity distribution and make preliminary judgments and predictions on the lithography results.

[0072] In one possible implementation, the initial electromagnetic field distribution of light after passing through the optical system is calculated based on the optical system information and the grayscale image. Specifically, the initial electromagnetic field distribution of light after passing through the optical system is calculated through a fast optical imaging model based on the optical system information and the grayscale image.

[0073] Specifically, the fast optical imaging model can be used to perform relevant calculations on the optical system information and the grayscale image, such as calculating the light propagation situation, so as to obtain the initial electromagnetic field distribution and improve the accuracy of the initial electromagnetic field distribution.

[0074] In addition, there can be many types of fast optical imaging models, for example, a plane wave expansion, that is, the fast optical imaging model is constructed based on the fast Fourier transform. In other words, the basis of the fast optical imaging model is the fast Fourier transform.

[0075] S104 , calculating and obtaining a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure.

[0076] Specifically, the propagation of light within the photoresist structure can be calculated to understand the residual photoresist structure that may be formed within the photoresist structure. Because the initial electromagnetic field distribution can reflect the distribution of light before entering the photoresist structure, combined with the structural parameters of the photoresist structure, the latent image of the photoresist obtained after etching the photoresist structure can be calculated.

[0077] The photoresist latent image may include the three-dimensional light intensity distribution of light in the photoresist structure, that is, the photoresist latent image is the three-dimensional light intensity distribution of light in the photoresist structure. After determining the three-dimensional light intensity distribution in the photoresist structure, the shape and contour of the residual photoresist structure can be determined based on the distribution.

[0078] In a possible implementation, the photoresist latent image is calculated based on the initial electromagnetic field distribution and the photoresist structure. Specifically, the photoresist latent image is calculated based on the initial electromagnetic field distribution and the photoresist structure using a transfer matrix method.

[0079] Specifically, the Transfer Matrix Method (TMM) can be used to calculate the three-dimensional light intensity distribution. TMM is an approximate method based on wave optics theory. It describes the transmission characteristics of the entire system by dividing the optical system into a series of thin slices and expressing the transmission characteristics of each slice as a transfer matrix. The transfer matrix is ​​a second-order square matrix that can completely describe the transmission process of light. In the TMM, each slice is described as a transfer matrix, which converts the amplitude and phase of the incident light into the amplitude and phase of the outgoing light.

[0080] In summary, the space between the light-emitting side of the digital micromirror array and the lower surface of the photoresist structure can be divided into multiple slices. The transfer matrix method can be used to calculate each slice more precisely, making the calculation results of the three-dimensional light intensity distribution more accurate.

[0081] In addition, the photoresist latent image can also be obtained based on the scalar defocus method, but through calculation, it is found that the calculation results obtained by the transfer matrix method are more accurate than those obtained by the scalar defocus method.

[0082] In one possible implementation, a photoresist latent image is calculated based on an initial electromagnetic field distribution and a photoresist structure by a transmission matrix method. Specifically, at least one first transmission matrix is ​​determined in an air environment; at least one second transmission matrix is ​​determined in the photoresist structure based on parameters of the photoresist structure; the parameters of the photoresist structure include thickness and refractive index; and the photoresist latent image is calculated based on the initial electromagnetic field distribution, the first transmission matrix, and the second transmission matrix.

[0083] Specifically, refer to Figure 6The figure shows a schematic diagram of the principle of a transmission matrix method provided by an embodiment of the present application. Multiple thin slices are divided in the z-axis direction, and only four are shown in the figure, namely Layer 1, Layer 2, Layer 3 and Layer 4. It is assumed that the electromagnetic field of interface 0 (at z = 0) on the front side of the first layer is defined as E0 and H0, and the electromagnetic field of interface 1 on the back side of Layer 1 is defined as E1 and H1. When emitting electromagnetic waves, it can be assumed that the electromagnetic waves start from interface 0, pass through Layer 1, and reach interface 1. The relationship between them needs to be established by the transmission matrix, which can be specifically expressed as:

[0084]

[0085] in, is the transmission matrix of Layer 1.

[0086] Furthermore, the electromagnetic field of interface 2 on the rear side of Layer 2 is defined as E2 and H2, which can be specifically expressed as:

[0087]

[0088] in, is the transmission matrix of Layer 2.

[0089] In an embodiment of the present application, the space between the light-emitting side of the digital micromirror array and the lower surface of the photoresist structure can be divided into a space in an air environment and a space where the photoresist structure is located. The space in the air environment can be divided into multiple thin slices, and the transmission matrix corresponding to each thin slice is determined and recorded as a first transmission matrix. The first transmission matrix can be determined based on the refractive index of the air environment, etc.

[0090] The space where the photoresist structure is located can also be divided into multiple thin slices, and based on the refractive index, thickness and other parameters of the photoresist structure, the transmission matrix corresponding to each thin slice is determined and recorded as the second transmission matrix.

[0091] In this way, by calculating the initial electromagnetic field distribution with the first transmission matrix of the first slice, the electromagnetic field distribution of the first slice can be obtained. By multiplying the initial electromagnetic field distribution, all the first transmission matrices, and all the second transmission matrices, the electromagnetic field distribution of the final slice can be obtained. In other words, the corresponding electromagnetic field distribution can be calculated for each slice, and by superimposing the electromagnetic field distributions of each layer, a three-dimensional light intensity distribution can be obtained. In this way, the transfer matrix method can be better applied to the calculation of light intensity distribution in this application, thereby obtaining a more accurate three-dimensional light intensity distribution.

[0092] S105 , determining a residual photoresist profile based on the photoresist latent image and the light intensity threshold.

[0093] Specifically, the three-dimensional light intensity distribution can be reflected in the photoresist latent image, allowing the residual photoresist profile formed when the photoresist structure is etched under this three-dimensional light intensity distribution to be determined. The residual photoresist profile can be understood as the profile of the photoresist remaining after etching the photoresist structure. The light intensity threshold can be used to determine whether the photoresist at a specific location will remain.

[0094] In this application, through the above-mentioned simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation results are relatively accurate. There is no need for manual testing, which saves a lot of manpower and material resources and improves efficiency. It can speed up the modification process of the design file, thereby photolithography out a device structure that meets the requirements, speeding up the process process, and improving the production efficiency of digital mask grayscale lithography.

[0095] In other words, this application can predict the results of digital mask grayscale lithography in advance, determine its deviation or deformation, and facilitate some pre-compensation and pre-correction work, thus avoiding repeated experiments that consume a lot of manpower and material resources, greatly reducing the experimental costs of digital lithography technology and expanding the application range of this lithography technology. Based on the simulation results, a basic judgment can be made on the design plan, and some obviously unreasonable designs can be effectively avoided, thereby improving the production efficiency of digital mask grayscale lithography.

[0096] In one possible implementation, the residual photoresist profile is determined based on the photoresist latent image and the light intensity threshold. Specifically, the two-dimensional light intensity distribution at the cross section of the photoresist structure is determined from the photoresist latent image; for each position, if the light intensity corresponding to the position is greater than the light intensity threshold, the position is determined to be located in an area outside the residual photoresist profile; otherwise, the position is determined to be located in an area within the residual photoresist profile; based on all positions of the area within the residual photoresist profile, their boundary lines are used as the residual photoresist profile.

[0097] Specifically, in order to quickly determine whether the residual photoresist profile meets the requirements, the profile of any cross section of the residual photoresist structure (on the xoz plane) can be used as the residual photoresist profile. The two-dimensional light intensity distribution corresponding to a cross section of the photoresist structure (on the xoz plane) can be intercepted from the three-dimensional light intensity distribution. The two-dimensional light intensity distribution includes the light intensity corresponding to each position. Figure 7The figure shows a schematic diagram of a two-dimensional light intensity distribution according to an embodiment of the present application, where the colors represent the light intensity. For each position on the plane corresponding to the two-dimensional light intensity distribution, the light intensity at that position can be compared with a light intensity threshold value, which can be set. If the light intensity at that position is greater than the light intensity threshold value, it indicates that the light intensity at that position is relatively strong, and the photoresist at that position will be removed. In other words, the position is determined to be outside the residual photoresist outline.

[0098] If the light intensity at that location is not greater than the light intensity threshold, it indicates that the light intensity at that location is relatively weak, and the photoresist will not be etched away. This means that the location is determined to be within the residual photoresist profile. In this way, for that plane, it is possible to determine whether the photoresist at each location will be retained, forming the final residual photoresist structure. For the region consisting of those locations where photoresist is retained, the boundary of that region is used as the residual photoresist profile.

[0099] refer to Figure 8 As shown, it is a schematic diagram of a residual photoresist profile provided in an embodiment of the present application, which is based on Figure 7 The two-dimensional light intensity distribution shown is calculated, the black part is the residual photoresist structure, and the residual photoresist outline is recorded as the edge of the black part. In short, in this way, the outline of the residual photoresist structure can be quickly and accurately determined.

[0100] In one possible implementation, the residual photoresist profile can be fitted to obtain a fitted profile, which is smoother and more even. The fitted profile is then compared with the preset profile to determine whether the design file meets the preset requirements. If the difference between the fitted profile and the preset profile is within an acceptable range, it can be determined that the design file of the digital micromirror array meets the preset requirements. Otherwise, it is determined that the design file does not meet the preset requirements and needs to be modified. Figure 9 , which is a schematic diagram of a fitting profile provided in an embodiment of the present application, wherein the dotted arc in the figure is the fitting profile.

[0101] In this way, by fitting the residual photoresist profile, the fitted profile will ignore tiny protrusions and depressions, making it easier to compare with the preset profile later, and it will be possible to quickly and accurately determine whether the design file is feasible.

[0102] In this application, through the above-mentioned simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation results are relatively accurate. There is no need for manual testing, which saves a lot of manpower and material resources and improves efficiency. It can speed up the modification process of the design file, thereby photolithography out a device structure that meets the requirements, speeding up the process process, and improving the production efficiency of digital mask grayscale lithography.

[0103] The present application also provides a digital lithography simulation device, referring to Figure 10 FIG. 1 is a schematic diagram of the structure of a digital lithography simulation device provided in an embodiment of the present application, comprising:

[0104] An acquisition unit 201 is configured to acquire a design file and an array diagram of a digital micromirror array, wherein the digital micromirror array includes a plurality of micromirrors; the design file includes the position, switch state, and on-time of each micromirror, and the array diagram includes the size and position of each micromirror;

[0105] A generating unit 202 is configured to generate a grayscale image of the digital micromirror array based on the design file and the array image; the grayscale image includes grayscale information of each micromirror;

[0106] A first calculation unit 203 is configured to calculate an initial electromagnetic field distribution of light after it passes through the optical system based on the optical system information and the grayscale image;

[0107] A second calculation unit 204 is configured to calculate a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure;

[0108] The determining unit 205 is configured to determine a residual photoresist profile based on the photoresist latent image and a light intensity threshold.

[0109] Optionally, the second computing unit is configured to:

[0110] Based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated by a transfer matrix method.

[0111] Optionally, the second computing unit is configured to:

[0112] determining at least one first transmission matrix in an air environment;

[0113] determining at least one second transmission matrix in the photoresist structure based on parameters of the photoresist structure, wherein the parameters of the photoresist structure include thickness and refractive index;

[0114] The photoresist latent image is calculated based on the initial electromagnetic field distribution, the first transmission matrix, and the second transmission matrix.

[0115] Optionally, the first computing unit is configured to:

[0116] Based on the optical system information and the grayscale image, the initial electromagnetic field distribution of the light after passing through the optical system is calculated using a fast optical imaging model.

[0117] Optionally, the fast optical imaging model is constructed based on fast Fourier transform.

[0118] Optionally, the determining unit is configured to:

[0119] Determining a two-dimensional light intensity distribution at a cross section of the photoresist structure from the photoresist latent image; the two-dimensional light intensity distribution includes light intensities corresponding to respective positions;

[0120] For each position, if the light intensity corresponding to the position is greater than the light intensity threshold, the position is determined to be located in a region outside the residual photoresist profile; otherwise, the position is determined to be located in a region within the residual photoresist profile;

[0121] Based on all positions of the region within the residual photoresist profile, their boundary lines are taken as the residual photoresist profile.

[0122] Optionally, the device further comprises:

[0123] A fitting unit, configured to fit the residual photoresist profile to obtain a fitting profile;

[0124] The comparison unit is used to compare the fitting profile with a preset profile to determine whether the design file meets the preset requirements.

[0125] In this application, through the above-mentioned simulation calculation process, the residual photoresist profile corresponding to the design file can be obtained, and the simulation results are relatively accurate. There is no need for manual testing, which saves a lot of manpower and material resources and improves efficiency. It can speed up the modification process of the design file, thereby photolithography out a device structure that meets the requirements, speeding up the process process, and improving the production efficiency of digital mask grayscale lithography.

[0126] On the other hand, the embodiment of the present application provides a computer device, referring to Figure 11 , which is a structural diagram of a computer device provided in an embodiment of the present application, includes a processor 310 and a memory 320:

[0127] The memory 320 is used to store program codes and transmit the program codes to the processor 310;

[0128] The processor 310 is configured to execute the method provided in the above embodiment according to the instructions in the program code.

[0129] The computer device may include a terminal device or a server, and the aforementioned apparatus may be configured in the computer device.

[0130] On the other hand, an embodiment of the present application further provides a storage medium, which is used to store a computer program, and the computer program is used to execute the method provided by the above embodiment.

[0131] Those skilled in the art will understand that all or part of the steps of implementing the above-mentioned method embodiment can be completed by program instruction hardware, and the above-mentioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above-mentioned method embodiment; and the above-mentioned storage medium can be at least one of the following media: read-only memory (English: Read-only Memory, abbreviated: ROM), RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0132] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from the other embodiments. In particular, the device embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0133] The above is only a preferred embodiment of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of protection of the technical solution of the present application.

Claims

1. A digital lithography simulation method, characterized in that: include: Obtaining a design file and an array diagram of a digital micromirror array comprising a plurality of micromirrors; The design file includes the position, switch state and on-time of each micromirror, and the array diagram includes the size and position of each micromirror; Based on the design file and the array diagram, a grayscale image of the digital micromirror array is generated; the grayscale image includes grayscale information of each micromirror; Calculating the initial electromagnetic field distribution of the light after it passes through the optical system based on the optical system information and the grayscale image; Based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure; A residual photoresist profile is determined based on the photoresist latent image and a light intensity threshold.

2. The method according to claim 1, characterized in that The calculating and obtaining a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure includes: Based on the initial electromagnetic field distribution and the photoresist structure, a photoresist latent image is calculated by a transfer matrix method.

3. The method according to claim 2, characterized in that The step of calculating a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure by using a transfer matrix method includes: determining at least one first transmission matrix in an air environment; determining at least one second transmission matrix in the photoresist structure based on parameters of the photoresist structure, wherein the parameters of the photoresist structure include thickness and refractive index; The photoresist latent image is calculated based on the initial electromagnetic field distribution, the first transmission matrix, and the second transmission matrix.

4. The method according to claim 1, wherein The calculating, based on the optical system information and the grayscale image, the initial electromagnetic field distribution of the light after passing through the optical system includes: Based on the optical system information and the grayscale image, the initial electromagnetic field distribution of the light after passing through the optical system is calculated using a fast optical imaging model.

5. The method according to claim 4, characterized in that The fast optical imaging model is constructed based on fast Fourier transform.

6. The method according to any one of claims 1 to 5, characterized in that The determining of the residual photoresist profile based on the photoresist latent image and the light intensity threshold comprises: Determining a two-dimensional light intensity distribution at a cross section of the photoresist structure from the photoresist latent image; the two-dimensional light intensity distribution includes light intensities corresponding to respective positions; For each position, if the light intensity corresponding to the position is greater than the light intensity threshold, the position is determined to be located in a region outside the residual photoresist profile; otherwise, the position is determined to be located in a region within the residual photoresist profile; Based on all positions of the region within the residual photoresist profile, their boundary lines are taken as the residual photoresist profile.

7. The method according to claim 6, characterized in that The method further comprises: Fitting the residual photoresist profile to obtain a fitting profile; The fitting profile is compared with a preset profile to determine whether the design file meets the preset requirements.

8. A digital lithography simulation device, characterized in that: include: An acquisition unit, configured to acquire a design file and an array diagram of a digital micromirror array comprising a plurality of micromirrors; The design file includes the position, switch state and on-time of each micromirror, and the array diagram includes the size and position of each micromirror; A generating unit, configured to generate a grayscale image of the digital micromirror array based on the design file and the array image; the grayscale image includes grayscale information of each of the micromirrors; a first calculation unit, configured to calculate an initial electromagnetic field distribution of light after it passes through the optical system based on the optical system information and the grayscale image; A second calculation unit is configured to calculate a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure; the photoresist latent image includes a three-dimensional light intensity distribution of light in the photoresist structure; A determining unit is configured to determine a residual photoresist profile based on the photoresist latent image and a light intensity threshold.

9. A computer device, characterized in that: The computer device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 7 according to instructions in the program code.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

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