Digital photoetching simulation method and related device

Abstract

The invention provides a digital photoetching simulation method and a related device. The method comprises the following steps: acquiring a design file and an array diagram of a digital micromirror array; the digital micromirror array comprises a plurality of micromirrors; based on the design file and the array diagram, generating a gray-scale map of the digital micromirror array; calculating initial electromagnetic field distribution of the light after passing through the optical system based on the optical system information and the grey-scale map; calculating to obtain a photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure; the photoresist latent image comprises three-dimensional light intensity distribution of light in the photoresist structure; and determining the contour of the residual photoresist based on the photoresist latent image and the light intensity threshold. Through the above simulation calculation process, the residual photoresist contour corresponding to the design file can be obtained, the simulation result is accurate, manual testing is not needed, a large amount of manpower and material resources are saved, the efficiency is improved, and the production efficiency of digital mask gray level photoetching is improved.

Description

Technical Field

[0001] The present application relates to the field of lithography, and in particular to a digital lithography 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. Large-area microstructure preparation is achieved by controlling the movement of the sample stage. In addition, grayscale lithography can be achieved more ideally by modulating the grayscale.

[0003] In the manufacturing process, similar to the mask design in traditional lithography, the grayscale distribution of the digital micromirror array designed in the digital mask system also needs the support and modification of experimental results. The initial design is not necessarily completely reasonable, but verification through experiments requires a lot of manpower and material resources. Therefore, providing a suitable digital lithography 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] On the one hand, 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 opening duration 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 of the micromirrors;

[0008] Based on the optical system information and the grayscale image, calculating the initial electromagnetic field distribution of the light after passing through the optical system;

[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 step of calculating the photoresist latent image based on the initial electromagnetic field distribution and the photoresist structure by using a transfer matrix method 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; the parameters of the photoresist structure including 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 the initial electromagnetic field distribution of the light after passing through the optical system based on the optical system information and the grayscale image 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 by 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 comprises:

[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 contour; otherwise, the position is determined to be located in a region within the residual photoresist contour;

[0023] Based on all positions of the regions 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, used to acquire 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 a position, a switch state, and an open time of each of the micromirrors, and the array diagram includes a size and a position of each of the micromirrors;

[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, configured 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 used 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 determination unit is used 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, the 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 devices, which obtain the design file and 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 opening 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 diagram of the digital micromirror array is generated; the grayscale diagram includes the grayscale information of each micromirror; based on the optical system information and the grayscale diagram, 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, the photoresist latent image is calculated; the photoresist latent image includes the three-dimensional light intensity distribution of light in the photoresist structure; based on the photoresist latent image and the light intensity threshold, the 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, and there is no need for manual testing, which saves a lot of manpower and material resources, and improves efficiency, and can speed up the modification process of the design file, so as to lithographically produce a device structure that meets the requirements, speed up the process process, and improve 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 the 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 diagram of the structure of a single micromirror provided in an embodiment of the present application is shown;

[0042] Figure 4 A schematic diagram of the structure 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 in an embodiment of the present application is shown;

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

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

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

[0049] Fig.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 objects, 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, but the present application may also be implemented in other ways different from those described herein, and 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, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of 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] The digital micromirror array is a group of flippable micromirrors that can modulate grayscale by controlling the flipping time. As a pattern generator, it is often used in the field of micro-nano processing and is also called a digital mask. Due to its flexibility, it can generate almost any required two-dimensional or even three-dimensional pattern, and using it to replace traditional masks will greatly reduce costs. Since it can produce images of different grayscales by controlling the flipping time of the micromirrors, digital micromirrors are often used in grayscale lithography. Its advantages of being able to adjust patterns and modulate grayscale at will make it a place in grayscale lithography.

[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 it takes a lot of manpower and material resources to verify it through experiments.

[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 result is relatively accurate. There is no need for manual experiments, 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 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 As shown, it is a flow chart of a digital lithography simulation method provided in an embodiment of the present application, and 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 may include multiple micromirrors, and is an array structure composed of a large number of micromirrors. In the digital lithography process, the digital micromirror array may be used as a mask for digital lithography. The design file corresponding to the digital micromirror array may be obtained. The format of the design file is not limited here. The design file may include the position, switch state, and opening time of each micromirror.

[0061] In other words, the design file can reflect the position of each micromirror, whether each micromirror is on or off, and the duration of the micromirror when it is on. In practical applications, when the micromirror is on, the micromirror reflects light to the main optical axis to form an image, and when the micromirror is off, the micromirror does not form an image. By controlling the micromirror to turn on or off, a binary image can be formed, that is, only including 0 and 1. As an example, the micromirror on can correspond to 1, and the micromirror off can correspond to 0.

[0062] refer to Figure 3 FIG. 1 is a schematic diagram of the structure of a single micromirror provided in an embodiment of the present application. The white area in the figure is the mirror surface of the micromirror, which can be controlled to be turned on or off. In addition, by controlling the opening time of the micromirror, images with different grayscales can be generated, for example, the grayscale level can be 256 levels or 512 levels, thereby realizing grayscale lithography.

[0063] Specifically, an array diagram of a digital micromirror array may be obtained, in which the size and position of each micromirror may be included. Figure 4 , which is a schematic diagram of the structure 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, and the array diagram can reflect the position and size of each micromirror, so that a grayscale image of the digital micromirror array can be generated based on the design file and the array diagram.

[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. As an 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] The grayscale image can be used as a mask, that is, because the grayscale image can reflect different grayscale values ​​at different positions, light with different light intensities at different positions can pass through, so it can replace the mask in traditional optical lithography. In practical applications, a simulation model of a digital lithography system can be established to complete the simulation calculation 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 surroundings, 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. Through 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. The 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 distribution of light after passing through the optical system can be reflected through the initial electromagnetic field distribution.

[0071] In addition, by calculating the initial electromagnetic field distribution, the two-dimensional light intensity distribution of light after passing through the optical system can be obtained. The 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 by 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, they can be plane wave expansion, that is, the fast optical imaging model is constructed based on fast Fourier transform. In other words, the basis of the fast optical imaging model is 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 in the photoresist structure can be calculated to know the residual photoresist structure that can be formed in the photoresist structure. Since 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 by a transfer matrix method based on the initial electromagnetic field distribution and the photoresist structure.

[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 the theory of wave optics. 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 fully describe the transmission process of light. In TMM, each slice is described as a transfer matrix that 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 thin slices. The transfer matrix method can be used to calculate each thin slice more precisely, making the calculation result 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 it is found through calculation that the calculation result obtained by the transfer matrix method is more accurate than the calculation result of the scalar defocus method.

[0082] In one possible implementation, based on the initial electromagnetic field distribution and the photoresist structure, the photoresist latent image is calculated by the transmission matrix method, which can be specifically as follows: at least one first transmission matrix in the air environment is determined; based on the parameters of the photoresist structure, at least one second transmission matrix in the photoresist structure is determined; the parameters of the photoresist structure include thickness and refractive index; based on the initial electromagnetic field distribution, the first transmission matrix and the second transmission matrix, the photoresist latent image is calculated.

[0083] Specifically, refer to Figure 6As shown, it is 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 the interface 0 (z = 0) on the front side of the first layer is defined as E0 and H0, and the electromagnetic field of the 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 Layer1.

[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 Layer2.

[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 under the air environment and a space where the photoresist structure is located. The space under the air environment can be divided into a plurality of thin slices, and a 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 and the first transmission matrix of the first sheet, the electromagnetic field distribution of the first sheet can be obtained, and by multiplying the initial electromagnetic field distribution, all the first transmission matrices and all the second transmission matrices, the electromagnetic field distribution of the last sheet can be obtained. That is, the corresponding electromagnetic field distribution can be calculated for each sheet, and the electromagnetic field distribution of each layer can be superimposed to obtain the three-dimensional light intensity distribution. In this way, the transmission matrix method can be better applied to the calculation of the light intensity distribution in this application, so that a more accurate three-dimensional light intensity distribution can be obtained.

[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, and then the residual photoresist profile formed when the photoresist structure is etched under the three-dimensional light intensity distribution can be determined. The residual photoresist profile can be understood as the profile of the photoresist remaining after the photoresist structure is etched. The light intensity threshold can be used to determine whether the photoresist at a certain position can remain.

[0094] 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 experiments, saving a lot of manpower and material resources, and improving efficiency. It can speed up the modification process of the design file, thereby lithographically producing 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, the present application can predict the results of digital mask grayscale lithography in advance, judge its deviation or deformation, and thus facilitate some pre-compensation and pre-correction work, thereby avoiding repeated experiments that consume a lot of manpower and material resources, greatly reducing the experimental cost of digital lithography technology, and expanding the application scope of this lithography technology. Based on the simulation results, a basic judgment can be made on the design scheme, 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 in 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, and the two-dimensional light intensity distribution includes the light intensity corresponding to each position. Figure 7As shown, a schematic diagram of a two-dimensional light intensity distribution provided by an embodiment of the present application is shown, and the color in the figure indicates the light intensity. For each position on the plane corresponding to the two-dimensional light intensity distribution, the light intensity at the position can be compared with the light intensity threshold, and the light intensity threshold can be set by itself. If the light intensity at the position is greater than the light intensity threshold, it means that the light intensity at the position is relatively strong, and the photoresist at this position will be removed, that is, the position is determined to be located in the area outside the residual photoresist contour.

[0098] If the light intensity at the position is not greater than the light intensity threshold, it means that the light intensity at the position is relatively weak, and the photoresist will not be etched away, that is, the position is determined to be within the residual photoresist profile. In this way, for the plane, it can be determined whether the photoresist at each position will be retained to form the final residual photoresist structure, so that for the area composed of those positions where the photoresist is retained, the boundary line of the area is used as the residual photoresist profile.

[0099] refer to Figure 8 FIG. 1 is a schematic diagram of a residual photoresist profile provided in an embodiment of the present application. Figure 7 The two-dimensional light intensity distribution shown is calculated, the black part is the residual photoresist structure, and the residual photoresist contour is recorded as the edge of the black part. In short, in this way, the contour of the residual photoresist structure can be quickly and accurately determined.

[0100] In a possible implementation, the residual photoresist profile can also be fitted to obtain a fitted profile, which is smoother and more even. The fitted profile is 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. Fig. 9 , which is a schematic diagram of a fitting contour provided in an embodiment of the present application, wherein the dotted arc in the figure is the fitting contour.

[0101] In this way, by fitting the residual photoresist contour, the fitted contour will ignore tiny protrusions and depressions, which is convenient for subsequent comparison with the preset contour, and can quickly and accurately determine whether the design file is feasible.

[0102] 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 experiments, saving a lot of manpower and material resources, and improving efficiency. It can speed up the modification process of the design file, thereby lithographically producing 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 Fig.10 FIG. 1 is a schematic diagram of a digital lithography simulation device provided in an embodiment of the present application, comprising:

[0104] The acquisition unit 201 is used to acquire 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 opening time of each micromirror, and the array diagram includes the size and position of each micromirror;

[0105] A generating unit 202 is used 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;

[0106] A first calculation unit 203, configured 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;

[0107] A second calculation unit 204 is used 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 determination 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 used for:

[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 used for:

[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; the parameters of the photoresist structure including 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 used for:

[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 by 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 used 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 contour; otherwise, the position is determined to be located in a region within the residual photoresist contour;

[0121] Based on all positions of the regions 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, used for fitting 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 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 experiments, saving a lot of manpower and material resources, and improving efficiency. It can speed up the modification process of the design file, thereby lithographically producing a device structure that meets the requirements, speeding up the process process, and improving the production efficiency of digital mask grayscale lithography.

[0126] In another aspect, the present application provides a computer device, referring to Fig.11 , which is a structural diagram of a computer device provided in an embodiment of the present application, wherein the computer device 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 used 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, wherein the storage medium is used to store a computer program, and the computer program is used to execute the method provided by the above embodiment.

[0131] A person skilled in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by program instruction hardware, and the above program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the above 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] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0133] The above is only a preferred implementation 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 of equivalent changes. Therefore, any simple modification, equivalent change and modification 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 still falls 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; the digital micromirror array includes a plurality of micromirrors; The design file includes the position, switch state and opening 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 of the micromirrors; Based on the optical system information and the grayscale image, calculating the initial electromagnetic field distribution of the light after passing through the optical system; 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 step of 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 comprises: 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; the parameters of the photoresist structure including 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, characterized in that: 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 comprises: 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 by 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 contour; otherwise, the position is determined to be located in a region within the residual photoresist contour; Based on all positions of the regions within the residual photoresist outline, their boundary lines are taken as the residual photoresist outline.

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, used to acquire 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 opening 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 used 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 determination unit is used 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 comprises 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 the 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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