Method, device, exposure equipment and computer-readable storage medium for generating holographic mask information

Abstract

The present invention relates to the field of photolithography technology, and in particular to a method, apparatus, exposure device, and computer-readable storage medium for generating holographic mask information. The present invention provides a method for generating holographic mask information, comprising: obtaining initial intensity information from a wafer surface, obtaining random phase information from the wafer surface based on the initial intensity information; subjecting the initial intensity information and random phase information to simulated propagation processing and discretization processing to obtain discrete phase information; filtering incident light modulated by the discrete phase information and propagating it to the wafer surface, and obtaining actual intensity information on the wafer surface; obtaining a gradient value based on the actual intensity information and the initial intensity information; determining whether the gradient value is less than or equal to a preset value, and if so, outputting holographic mask information based on the discretized phase information and a preset amplitude value. This method solves the problem of holographic speckle in holographic masks during the photolithography process.

Description

Technical field

[0001] The present invention relates to the field of photolithography technology, and in particular to a method and device for generating holographic mask information, an exposure device, and a computer-readable storage medium. [Background Technology]

[0002] Holographic diffraction lithography uses the diffraction and interference effects of light to construct an aerial image to create integrated circuit layouts. Unlike the masks used in traditional projection lithography, holographic masks are composed of a group of small holes that record all the information about the target pattern. After the incident light is diffracted by the mask, the diffraction pattern produced by each small hole "assembles" to form the target pattern on the wafer for exposure. Holographic diffraction lithography calculates the optical diffraction model of the target pattern and records all the target pattern information on the mask. Highly coherent laser light is used as the incident light. After passing through the holographic mask, it diffracts and forms an aerial image of the target pattern on the wafer, thereby transferring the target pattern to the wafer.

[0003] The core of phase holographic mask generation is phase retrieval, which can be solved using both iterative and non-iterative methods. Iterative algorithms continuously iterate and constrain phase values ​​until the updated phase hologram meets the requirements before outputting it. Non-iterative methods, on the other hand, perform a single calculation based on given data and conditions, resulting in inferior reconstruction quality. During the iterative process, incident light passing through the mask inevitably introduces constructive and destructive interference, leaving behind bright and dark spots. These bright and dark spots are known as holographic speckle. Holographic speckle is a form of background noise that significantly impacts lithography quality. [Summary of the invention]

[0004] In order to solve the problem of holographic speckle in a holographic mask during a photolithography process, the present invention provides a method and apparatus for generating holographic mask information, an exposure device, and a computer-readable storage medium.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for generating holographic mask information, comprising:

[0006] Obtaining initial intensity information of the wafer surface, and obtaining random phase information of the wafer surface based on the initial intensity information;

[0007] The initial intensity information and random phase information are subjected to simulated propagation processing and discretization processing to obtain discretized phase information;

[0008] The incident light modulated by the discrete phase information is filtered and propagated to the wafer surface, and the actual intensity information of the wafer surface is obtained;

[0009] Obtaining a gradient value based on actual intensity information and initial intensity information;

[0010] Determine whether the gradient value is less than or equal to a preset value;

[0011] If so, the holographic mask information is output based on the discretized phase information and the preset amplitude value.

[0012] Preferably, determining whether the gradient value is less than or equal to a preset value further includes:

[0013] If not, the discretized phase information is used as random phase information, and the initial intensity information and the random phase information are iteratively subjected to the process of simulated propagation processing and discretization processing.

[0014] Preferably, performing simulation propagation processing and discretization processing on the initial intensity information and random phase information includes:

[0015] acquiring an initial wavefront on the wafer surface based on initial intensity information and random phase information;

[0016] Simulating the process of the initial wavefront propagating from the wafer surface to the holographic mask surface and obtaining a simulated wavefront;

[0017] The simulated wavefront is discretized to obtain discrete phase information.

[0018] Preferably, the process of simulating the propagation of the initial wavefront from the wafer surface to the holographic mask surface includes: using a preset simulation algorithm to simulate the propagation of the initial wavefront from the wafer surface to the holographic mask surface;

[0019] The preset simulation algorithm is the plane wave angular spectrum method.

[0020] Preferably, performing filtering processing specifically includes:

[0021] Get the dimensions of the holographic mask;

[0022] Setting an interval based on the dimension, and extracting a preset number of parameter values ​​within the interval;

[0023] Set the total number of iterations, divide the number of iterations into multiple levels, determine the level of the current iteration and obtain the parameter value corresponding to the current iteration;

[0024] Obtain the corresponding Gaussian filter based on the parameter value corresponding to the current iteration through the preset filtering algorithm;

[0025] The modulated incident light is filtered using a Gaussian filter.

[0026] Preferably, the preset filtering algorithm is:

[0027] W(k)=exp[(-1 / 2)×(k / a) 2 ];

[0028] Where k is the spatial frequency, W(k) is the Gaussian filter function with k as the independent variable, and a is the parameter value corresponding to the current iteration.

[0029] Preferably, obtaining the gradient value based on the actual intensity information and the initial intensity information specifically includes:

[0030] Obtain the error value between the actual intensity information and the initial intensity information;

[0031] A gradient value is obtained by a preset formula based on the error value and the discretized phase information;

[0032] The preset formula is:

[0033] CF=∑(I i -I0) 2 ;

[0034]

[0035] Among them, I0 is the initial intensity information, I i is the actual intensity information, CF is the error between the actual intensity information and the initial intensity information, is the discretized phase information, δ is the gradient value, and the preset value is 0.03.

[0036] In order to solve the above technical problems, the present invention provides another technical solution as follows: a holographic mask information generating device, the holographic mask information generating device comprising:

[0037] Acquisition module: used to obtain initial intensity information of the wafer surface, and obtain random phase information of the wafer surface based on the initial intensity information;

[0038] Processing module: used for performing simulation propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information;

[0039] Simulation module: used to filter the incident light modulated by the discrete phase information and transmit it to the wafer surface, and obtain the actual intensity information of the wafer surface;

[0040] Judgment module: obtains a gradient value based on the actual intensity information and the initial intensity information, and determines whether the gradient value is less than or equal to a preset value;

[0041] Output module: used to determine whether to output holographic mask information based on the discretized phase information and the preset amplitude value based on the result of the judgment module.

[0042] In order to solve the above technical problems, the present invention provides another technical solution as follows: an exposure device, including a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to implement the holographic mask information generation optimization method.

[0043] In order to solve the above technical problems, the present invention provides another technical solution as follows: a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the above-mentioned holographic mask information generation method.

[0044] Compared with the prior art, the holographic mask information generation method, device, exposure equipment, and computer-readable storage medium provided by the present invention have the following beneficial effects:

[0045] 1. An embodiment of the present invention provides a method for generating holographic mask information, comprising: obtaining initial intensity information from a wafer surface, and obtaining random phase information from the wafer surface based on the initial intensity information; performing simulated propagation processing and discretization processing on the initial intensity information and the random phase information to obtain discrete phase information; filtering incident light modulated by the discrete phase information and then propagating it to the wafer surface, and obtaining actual intensity information from the wafer surface; obtaining a gradient value based on the actual intensity information and the initial intensity information; and determining whether the gradient value is less than or equal to a preset value. If so, outputting holographic mask information based on the discretized phase information and the preset amplitude value.

[0046] 2. The present invention simulates propagation and discretizes initial intensity information and random phase information, including: obtaining an initial wavefront on the wafer surface based on the initial intensity information and random phase information; simulating the propagation of the initial wavefront from the wafer surface to the holographic mask surface to obtain a simulated wavefront; and discretizing the simulated wavefront to obtain discrete phase information. Discretization reduces computational complexity and improves accuracy. Specifically, discretization divides the optical signal into discrete data points, making digital signal processing and analysis as convenient as with other digital signals, further improving computational efficiency and accuracy.

[0047] 3. In an embodiment of the present invention, simulating the process of an initial wavefront propagating from a wafer surface to a holographic mask surface includes: simulating the process of an initial wavefront propagating from a wafer surface to a holographic mask surface using a preset simulation algorithm. The preset simulation algorithm is a plane wave angular spectrum method. Using the preset simulation algorithm, the process of an initial wavefront propagating from a wafer surface to a holographic mask surface can be simulated efficiently and simply.

[0048] 4. The filtering process performed in the embodiments of the present invention specifically includes: obtaining the dimensions of the holographic mask; setting an interval based on the dimensions and extracting a preset number of parameter values ​​within the interval; setting a total number of iterations, dividing the number of iterations into multiple levels, determining the level of the current iteration and obtaining the parameter value corresponding to the current iteration; obtaining a corresponding Gaussian filter using a preset filtering algorithm based on the parameter value corresponding to the current iteration; and filtering the modulated incident light using the Gaussian filter to remove holographic speckle and improve lithography quality.

[0049] 5. In the embodiment of the present invention, obtaining a gradient value based on actual intensity information and initial intensity information specifically includes: obtaining an error value between the actual intensity information and the initial intensity information; and obtaining a gradient value using a preset formula based on the error value and discretized phase information.

[0050] The preset formula is:

[0051] CF=∑(I i -I0) 2 ;

[0052]

[0053] Among them, I0 is the initial intensity information, I i is the actual intensity information, CF is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value. By calculating the error between the actual intensity information and the initial light intensity information, we can determine whether the current phase reconstruction effect meets the requirements and make adjustments and optimizations.

[0054] 6. The embodiment of the present invention further provides a holographic mask information generating device, which has the same beneficial effects as the above-mentioned holographic mask information generating method, and will not be described in detail here.

[0055] 7. An embodiment of the present invention further provides an exposure device having the same beneficial effects as the above-mentioned method for generating holographic mask information, which will not be described in detail here.

[0056] 8. An embodiment of the present invention further provides a computer-readable storage medium, which has the same beneficial effects as the above-mentioned method for generating holographic mask information, and will not be described in detail here.

Brief Description of the Drawings

[0057] Figure 1 The figure is a flow chart of a method for generating holographic mask information provided by an embodiment of the present invention.

[0058] Figure 2 It is a schematic diagram of the process of propagating the initial wavefront from the wafer surface to the holographic mask in a method for generating holographic mask information provided by an embodiment of the present invention.

[0059] Figure 3 It is a schematic diagram of a filtering process flow of a holographic mask information generation method provided by an embodiment of the present invention.

[0060] Figure 4 It is a structural schematic diagram of a holographic mask information generating device provided by an embodiment of the present invention.

[0061] Description of the accompanying drawings:

[0062] 1. Holographic mask information generating device;

[0063] 11. Acquisition module; 12. Processing module; 13. Simulation module; 14. Judgment module; 15. Output module. [Specific implementation method]

[0064] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0065] In the embodiments provided herein, it should be understood that "B corresponding to A" means that B is associated with A and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B based solely on A; B can also be determined based on A and / or other information.

[0066] It should be understood that references to "one embodiment" or "an embodiment" throughout this specification mean that specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present invention. Therefore, the appearance of "in one embodiment" or "in an embodiment" throughout this specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Those skilled in the art should also be aware that the embodiments described in this specification are all optional embodiments, and the actions and modules involved are not necessarily required for the present invention.

[0067] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the above-mentioned processes does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0068] The flow charts and block diagrams in the accompanying drawings of the present invention illustrate the possible implementation architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementation schemes, the functions marked in the box can also occur in a different order than those marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which is determined based on the functions involved. It should be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0069] During photolithography, users typically process the surface of a wafer or silicon chip using incident light through a holographic mask. A mask is an optical obscurant with a specific pattern that selectively blocks or transmits incident light to create the desired pattern on the silicon wafer. The mask typically consists of transparent and opaque areas to create the desired pattern. Holographic masks utilize holographic technology, where the pattern is created by recording the interference effects of incident light waves. This means that a holographic mask contains not only amplitude information about the pattern but also phase information. This phase information enables holographic masks to produce highly complex optical effects. With the right holographic mask, highly complex patterns can be formed on silicon wafers that would be impossible to create using traditional planar masks. It should be understood that incident light refers to light emitted by specialized light sources, such as extreme ultraviolet (EUV), deep ultraviolet (DUV), or argon fluoride (ArF). Passing through the mask, incident light inevitably introduces constructive and destructive interference, resulting in bright and dark spots.

[0070] It should be understood that constructive interference occurs when two or more incident light waves (or wavefronts) meet, causing their peaks and troughs to align, resulting in an addition of their amplitudes, creating a stronger optical signal. This phenomenon increases the light intensity in certain areas, creating bright spots. In photolithography, constructive interference can be used to enhance the exposure of a desired pattern. Destructive interference occurs when two or more incident light waves meet, causing their peaks and troughs to shift, causing their amplitudes to decrease, resulting in a weaker light signal. This phenomenon reduces the light intensity in certain areas, creating dark spots. In photolithography, destructive interference can lead to incomplete or distorted patterns. These two interference effects are the result of optical interference and diffraction, typically occurring on a silicon wafer after the incident light passes through a mask. In the photolithography process, engineers must precisely control the parameters of the incident light and the optical system to minimize destructive interference while leveraging constructive interference to ensure high-quality reproduction of the desired pattern. These bright and dark spots are known as holographic speckle. Holographic speckle is essentially a kind of background noise, and the management of holographic speckle (including bright spots and dark spots) directly affects the quality and performance of chip manufacturing.

[0071] To solve the above problem, please refer to Figure 1 , an embodiment of the present invention provides a method for generating holographic mask information, comprising the following steps:

[0072] S1, obtaining initial intensity information of the wafer surface, and obtaining random phase information of the wafer surface based on the initial intensity information;

[0073] S2, simulates propagation processing and discretization of the initial intensity information and random phase information to obtain discretized phase information;

[0074] S3, the incident light modulated by the discrete phase information is filtered and propagated to the wafer surface, and the actual intensity information of the wafer surface is obtained;

[0075] S4, obtaining a gradient value based on the actual intensity information and the initial intensity information;

[0076] S5, determining whether the gradient value is less than or equal to a preset value;

[0077] S6: If yes, output holographic mask information based on the discretized phase information and the preset amplitude value.

[0078] It can be understood that in this embodiment, the initial intensity information of the wafer surface is first obtained, and then the random phase information of the wafer surface is obtained based on the initial intensity information of the wafer surface. Specifically, the random phase information is randomly generated based on the initial intensity information. Furthermore, the initial intensity information and the random phase information are discretized to obtain the discrete intensity information and the discrete phase information. At this time, the discretized intensity information is set to a unit value, and the discretized phase information can be used as the phase value of the pixel points distributed on the holographic mask. Furthermore, the incident light is filtered after passing through the holographic mask, and the filtered incident light is propagated to the wafer surface to obtain the actual intensity information, and then the gradient value is obtained based on the actual intensity information and the initial intensity information. By comparing the gradient value with the preset value, it can be determined whether the output based on the discretized phase information and the preset amplitude value is to be used as the holographic mask information.

[0079] It should be understood that discretizing the initial intensity information and random phase information in this embodiment can reduce computational complexity and improve accuracy. Specifically, discretization can divide the optical signal into discrete data points, facilitating digital signal processing and analysis like other digital signals, further improving computational efficiency and accuracy. Furthermore, holographic speckle is essentially a form of background noise. In this embodiment, the incident light entering the holographic mask is modulated by the discretized phase information and then filtered to reduce noise, thereby eliminating the problem of holographic speckle during the lithography process. This, in turn, improves the lithography quality of the generated holographic mask.

[0080] Furthermore, in the above step S2, the simulation propagation processing and discretization processing of the initial intensity information and the random phase information specifically include:

[0081] S21, acquiring an initial wavefront on the wafer surface based on the initial intensity information and the random phase information;

[0082] S22, simulating a process in which the initial wavefront propagates from the wafer surface to the holographic mask surface, and obtaining a simulated wavefront;

[0083] S23, discretizing the simulated wavefront to obtain discrete phase information.

[0084] It should be understood that the surface formed by each equal-phase point in a light beam is perpendicular to the propagation direction of each point in the beam. During wave propagation, these points of equal phase form a continuous surface or line. Intensity refers to the energy density of a wave, representing the energy passing through a unit area. In light waves, intensity is proportional to the square of the wave's amplitude. Phase refers to the phase difference of a wave, indicating the relative alignment between different points on the wavefront. Phase determines phenomena such as phase difference, interference, and diffraction. The wavefront is closely related to its phase and intensity. The vibration state (phase) of each point on the wavefront is the same, meaning that the wavefront can be viewed as an equal-phase surface with the same phase. However, the intensity or energy density of the wavefront may vary at different locations on the wavefront. Therefore, once the initial intensity information and random phase information on the wafer surface are acquired, the corresponding initial wavefront can be obtained. Before and after acquiring the initial wavefront, the propagation of the initial wavefront from the wafer surface to the holographic mask surface is simulated to complete the simulation process and obtain the simulated wavefront. Finally, the simulated wavefront is discretized to obtain the discrete phase information. In this embodiment, the discrete phase information can be obtained simply and conveniently by performing simulated propagation processing and discretization processing on the initial intensity information and the random phase information.

[0085] It should be noted that the holographic mask includes the phase information of the pattern. While the discretized intensity information is typically set to a unit value, the discretized phase information serves as the phase value for each pixel on the holographic mask pattern. When incident light strikes the holographic mask surface, the discretized phase information on the holographic mask can be used to phase modulate the incident light.

[0086] Specifically, phase modulation of incident light by a holographic mask refers to the process of interferometrically modulating light by altering the phase information on the holographic mask. This process typically involves two stages: recording and reconstruction. In the recording stage, the discretized phase information serves as the phase value for each pixel on the holographic mask pattern. During this process, the holographic mask records both discrete intensity information and discrete phase information. In the reconstruction stage, as the incident light passes through the holographic mask, it interacts with the pattern recorded on the holographic mask. The phase modulation of the incident light changes the phase of the incident light, and the pattern recorded on the holographic mask is reconstructed, thereby producing an image of the object. It should be understood that the phase modulation of the holographic mask causes both the intensity and phase of the incident light to change. During the phase modulation process, the discretized phase information on the holographic mask affects the phase distribution of the incident light, causing the phase of the incident light to vary at different locations. This variation leads to the formation and reconstruction of the pattern. Consequently, a corresponding relationship is established between the intensity distribution of the incident light and the pattern, enabling the recording and reconstruction of object information.

[0087] Specifically, in step 23, the analog wavefront is discretized to obtain discrete phase information. Discretization can reduce computational complexity and improve accuracy. Specifically, discretization can divide the optical signal into discrete data points, making digital signal processing and analysis easier, just like other digital signals, further improving computational efficiency and accuracy.

[0088] Furthermore, the process of simulating the initial wavefront propagating from the wafer surface to the holographic mask surface specifically includes: using a preset simulation algorithm to simulate the initial wavefront propagating from the wafer surface to the holographic mask surface.

[0089] Preferably, the preset simulation algorithm is the angular spectrum method. Specifically, the initial wavefront on the wafer surface at plane Σ0 with z=0 can be written as E0(x0,y0). When propagating to the holographic mask surface at a distance z, the simulated wavefront on the holographic mask plane can be written as:

[0090]

[0091] Among them, A0(k x ,k y ) represents the Fourier transform of E0(x0,y0), (k x ,k y ) represents the spatial frequency of the complex amplitude of the wavefront, circ represents the unit space circular function, the value is 1 in the region with a radius of 1, and 0 elsewhere, and it is defined that k^2>kx^2+ky^2. It should be understood that the angular spectrum method used in this embodiment can accurately simulate the propagation of the initial wavefront from the wafer surface to the holographic mask surface, and then obtain the simulated wavefront of the initial wavefront propagating to the holographic mask surface. The angular spectrum method has the advantages of a wide range of applications, simple numerical calculations, high accuracy, and short calculation time. The angular spectrum method can be used to simulate the process of the initial wavefront propagating from the wafer surface to the holographic mask surface in an efficient and simple manner.

[0092] Furthermore, the incident light modulated by the discrete phase information is filtered and then propagated to the wafer surface.

[0093] Specifically, please combine Figure 1 and Figure 3 In the above step S3, the filtering process specifically includes:

[0094] S31, obtaining the dimension N×N of the holographic mask;

[0095] S32, setting an interval (N, 1 / N) based on the dimension, and extracting a preset number of parameter values ​​within the interval;

[0096] S33, setting the total number of iterations, dividing the number of iterations into multiple levels, determining the level of the current iteration and obtaining the parameter value corresponding to the current iteration;

[0097] S34, obtaining a corresponding Gaussian filter using a preset filtering algorithm based on the parameter value corresponding to the current iteration;

[0098] S35, using a Gaussian filter to filter the modulated incident light.

[0099] It should be understood that the dimension N×N of the holographic mask refers to the number of pixels in the mask, that is, the number of points in the horizontal and vertical directions. The dimension of the holographic mask determines the maximum object size and resolution that can be encoded and reconstructed. Holographic masks are typically produced using an equidistant source distribution. Each pixel represents a sampling point in the light field. Therefore, a greater number of pixels represents a greater number of light field sampling points, allowing for more accurate restoration of the object's wavefront information and achieving higher object resolution. Typically, each pixel in the N×N matrix corresponds to a tiny area of ​​the mask template. Therefore, the size of N can affect the detail resolution of the mask template. Generally, a larger value results in higher mask accuracy, but also requires greater computational effort. A preset number of parameter values ​​can be extracted within the interval. These values ​​can be used in subsequent iterations to obtain the corresponding Gaussian filter. It should be understood that a Gaussian filter is a mathematical model that converts image data into energy. Noise is a high-frequency component, and smoothing with a Gaussian filter can reduce its impact.

[0100] Specifically, the number of iterations is classified and the current iteration is matched to the parameter values ​​one by one. It should be noted that the purpose of classification is to improve the efficiency of filtering. At different iteration stages, the range of high-frequency noise to be filtered may vary. Therefore, to meet the needs of different stages, different Gaussian filter parameter values ​​need to be selected at different iteration stages. Therefore, first, the classification is used to determine the stage of the current iteration. Then, the Gaussian filter parameters required for that stage can be selected based on the pre-set parameter values ​​for subsequent phase reconstruction calculations.

[0101] For example, the dimensions of the holographic mask are 1×1; the interval is set to (1, 1 / 10), 10 parameter values ​​are advanced within the interval, the number of iterations is set to 100, and the 100 iterations are divided into 10 levels, for example, 0-9 times are the first level, and 10-19 are the second level. The level of the current iteration is determined and the parameter value corresponding to the current iteration is obtained. For example, if the current iteration is in the first level, the corresponding parameter values ​​in the first level are all the same. Based on the parameter value corresponding to the current iteration, a corresponding Gaussian filter is obtained using a preset filtering algorithm, and the modulated incident light is then filtered using the Gaussian filter.

[0102] Specifically, in the above step S34, the preset filtering algorithm is:

[0103] W(k)=exp[(-1 / 2)×(k / a) 2 ];

[0104] Where k is the spatial frequency, W(k) is the Gaussian filter function with k as the independent variable, and a is the parameter value corresponding to the current iteration. It should be understood that the Gaussian filter is introduced to reduce the noise of the modulated incident light to improve the quality of image reconstruction. For different numbers of iterations, the corresponding Gaussian filter is introduced for processing, and the filtering frequency gradually increases from low frequency to high frequency, thereby achieving noise reduction processing in the full frequency domain. Low-frequency information determines the contour morphology of the image, and high-frequency information determines the details of the image. Therefore, by introducing Gaussian filters with different effects, full processing of different areas of the image can be achieved.

[0105] Furthermore, in the above step S3, the incident light modulated by the discrete phase information is filtered and then propagated to the wafer surface, specifically including:

[0106] Obtaining the intensity and phase of the incident light modulated by the discretized phase information;

[0107] Obtaining a modulated wavefront based on the intensity and phase of the modulated incident light;

[0108] The Rayleigh-Sommerfeld diffraction algorithm is used to simulate the process of the modulated wavefront propagating from the holographic mask to the wafer surface, and the actual intensity on the wafer surface is obtained.

[0109] Specifically, the simulation of the focused incident light passing through the holographic mask to form an image on the wafer can be achieved using the following Rayleigh-Sommerfeld diffraction integral formula (where the diffraction distance z is much larger than the wavelength λ of the irradiated light):

[0110]

[0111] Among them, d represents the distance from the convergence point of the spherical wave to the mask surface, and the wavefront information U′(ξ,η) of the incident light after passing through the mask is distributed on the wafer surface as wavefront U(x,y,z) after passing the diffraction distance z. (ξ,η) represents the spatial coordinates of the mask surface, (x,y) represents the spatial coordinates on the wafer surface, j represents the imaginary unit, and k represents the wave vector. It should be understood that the Rayleigh-Sommerfeld diffraction can be used to conveniently simulate the process of incident light propagating to the wafer surface after passing through the holographic mask. Specifically, after the incident light is modulated by the holographic mask, the modulated wavefront can be obtained by obtaining its modulated intensity and phase. Then, based on the Rayleigh-Sommerfeld diffraction algorithm, the modulated wavefront is simulated to propagate from the holographic mask to the wafer surface, and the actual light intensity on the wafer surface during the simulation process is accurately obtained.

[0112] Furthermore, in steps S3 to S7, a preset value is set and the gradient value is compared with the preset value to determine whether the discretized phase meets the standard during the iteration process. As a possible implementation, when the gradient value is less than or equal to the preset value, the discretized phase information can be directly output, and the holographic mask information can be output based on the discretized phase information and the preset amplitude value. Specifically, the holographic mask information refers to the preset amplitude value multiplied by the discretized phase information, and the preset amplitude value can be set to 1. If the gradient value and the preset value are equal, the preset amplitude value is directly multiplied by the current discretized phase information and output as the holographic mask information. It should be noted that the setting value of the preset amplitude value is only a possible implementation method, and its specific numerical value is not limited.

[0113] As another possible implementation, determining whether the gradient value is less than or equal to a preset value further includes:

[0114] S7: If not, the discretized phase information is used as random phase information, and the initial intensity information and the random phase information are iteratively subjected to a process of simulated propagation processing and discretization processing.

[0115] It should be understood that when the gradient value is greater than the preset value, that is, it does not meet the standard, it is necessary to retain the discretized phase information on the current wafer surface, and obtain the wavefront to be processed based on the known initial intensity information and the discretized phase information, and use the wavefront to be processed as the initial wavefront and iterate the process from step S2 to step S7. It should be noted that in the new iterative process, the parameters of the Gaussian filter may need to be adjusted to improve the reconstruction effect. After multiple iterations, the filtered discretized phase information can be gradually adjusted to obtain a more precise and accurate reconstruction result, and the error between the actual intensity information and the initial light intensity information will continue to decrease, achieving the expected effect target. Therefore, iterative processing can help improve reconstruction efficiency and accuracy.

[0116] Specifically, the value of the initial intensity information is the same in each iteration, that is, the initial intensity information of the wafer surface obtained in step S1 is used in each iteration. However, what is actually sent during each iteration is the phase information. For example, in this embodiment, if the gradient value is greater than the preset value, and the discretized phase information is Then the discretized phase information is As random phase information, the initial intensity information and random phase information are simulated and propagated and discretized to obtain the discretized phase information after the first iteration. If the gradient value after the first iteration is still greater than the preset value, the discretized phase information obtained after the first iteration is Replace the phase information of the first iteration Discrete phase information The discretized phase information obtained by the second iteration of the simulated propagation processing and discretization processing with the initial intensity information

[0117] Furthermore, if the gradient value after the second iteration is still greater than the preset value, the discretized phase information obtained after the second iteration is continued to be Replace the phase information in the second iteration The third iteration process is continued until the gradient value is less than or equal to the preset value, and the iteration process is completed.

[0118] Specifically, in the above step S4, obtaining the gradient value based on the actual intensity information and the initial intensity information specifically includes:

[0119] Obtain the error value between the actual intensity information and the initial intensity information;

[0120] A gradient value is obtained by a preset formula based on the error value and the discretized phase information;

[0121] The preset formula is:

[0122] CF=∑(I i -I0) 2 ;

[0123]

[0124] Among them, I0 is the initial intensity information, I i is the actual intensity information, CF is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value.

[0125] It should be understood that the initial light intensity information is a reference value obtained based on wafer surface information. The actual intensity information, on the other hand, reflects the propagation and diffraction characteristics. It reflects the impact of factors such as loss, noise, and error during the propagation and diffraction of light on the light field, thereby evaluating and optimizing the performance of the optical system. By calculating the error between the actual intensity information and the initial light intensity information, it is possible to determine whether the current phase reconstruction effect meets the requirements and make adjustments and optimizations accordingly.

[0126] Specifically, the preset value is 0.03. It should be understood that if the gradient values ​​of all points on the current wafer surface are less than or equal to 0.03, it means that the current reconstruction effect has met the requirements, the holographic mask information can be output, and the iterative process is ended. The output holographic mask information can be used to manufacture the actual mask. If the gradient value is greater than 0.03, the next iterative optimization is required until the expected reconstruction effect is achieved. Therefore, the setting of the gradient value is an important parameter in the phase reconstruction algorithm, which can affect the reconstruction efficiency and accuracy. It should be noted that the specific setting value of the preset value is related to the actual needs of the user, and this embodiment only provides an example display.

[0127] Please combine Figure 1 and Figure 4 In order to solve the above technical problems, the present invention further provides a holographic mask information generating device 1, the holographic mask information generating device 1 comprising:

[0128] Acquisition module 11: used to obtain initial intensity information of the wafer surface, and obtain random phase information of the wafer surface according to the initial intensity information;

[0129] Processing module 12: configured to perform simulated propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information;

[0130] Simulation module 13: used to filter the incident light modulated by the discrete phase information and transmit it to the wafer surface, and obtain the actual intensity information of the wafer surface;

[0131] Determination module 14: obtains a gradient value based on the actual intensity information and the initial intensity information, and determines whether the gradient value is less than or equal to a preset value;

[0132] The output module 15 is configured to determine, based on the result of the determination module 14 , whether to output the holographic mask information based on the discretized phase information and the preset amplitude value.

[0133] The holographic mask information generating device 1 provided in this embodiment has the same beneficial effects as the above-mentioned holographic mask information generating method, which will not be described in detail here.

[0134] In order to solve the above technical problems, the present invention also provides an exposure device, including a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to implement the above holographic mask information generation optimization method.

[0135] An embodiment of the present invention further provides an exposure device having the same beneficial effects as the above-mentioned method for generating holographic mask information, which will not be described in detail here.

[0136] In order to solve the above technical problem, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the above holographic mask information generating method.

[0137] It should be noted that a computer-readable storage medium may be a tangible medium that may contain or store a program for use by an instruction execution system, device, or apparatus or used in conjunction with an instruction execution system, device, or apparatus. A computer-readable storage medium may be a machine-readable signal medium or a machine-readable storage medium. A computer-readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the foregoing. More specific examples of computer-readable storage media may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0138] Compared with the prior art, the holographic mask information generation method, device, exposure equipment, and computer-readable storage medium provided by the present invention have the following beneficial effects:

[0139] 1. An embodiment of the present invention provides a method for generating holographic mask information, comprising: obtaining initial intensity information from a wafer surface, and obtaining random phase information from the wafer surface based on the initial intensity information; performing simulated propagation processing and discretization processing on the initial intensity information and the random phase information to obtain discrete phase information; filtering incident light modulated by the discrete phase information and then propagating it to the wafer surface, and obtaining actual intensity information from the wafer surface; obtaining a gradient value based on the actual intensity information and the initial intensity information; and determining whether the gradient value is less than or equal to a preset value. If so, outputting holographic mask information based on the discretized phase information and the preset amplitude value.

[0140] 2. The present invention simulates propagation and discretizes initial intensity information and random phase information, including: obtaining an initial wavefront on the wafer surface based on the initial intensity information and random phase information; simulating the propagation of the initial wavefront from the wafer surface to the holographic mask surface to obtain a simulated wavefront; and discretizing the simulated wavefront to obtain discrete phase information. Discretization reduces computational complexity and improves accuracy. Specifically, discretization divides the optical signal into discrete data points, making digital signal processing and analysis as convenient as with other digital signals, further improving computational efficiency and accuracy.

[0141] 3. In an embodiment of the present invention, simulating the process of an initial wavefront propagating from a wafer surface to a holographic mask surface includes: simulating the process of an initial wavefront propagating from a wafer surface to a holographic mask surface using a preset simulation algorithm. The preset simulation algorithm is a plane wave angular spectrum method. Using the preset simulation algorithm, the process of an initial wavefront propagating from a wafer surface to a holographic mask surface can be simulated efficiently and simply.

[0142] 4. The filtering process performed in the embodiments of the present invention specifically includes: obtaining the dimensions of the holographic mask; setting an interval based on the dimensions and extracting a preset number of parameter values ​​within the interval; setting a total number of iterations, dividing the number of iterations into multiple levels, determining the level of the current iteration and obtaining the parameter value corresponding to the current iteration; obtaining a corresponding Gaussian filter using a preset filtering algorithm based on the parameter value corresponding to the current iteration; and filtering the modulated incident light using the Gaussian filter to remove holographic speckle and improve lithography quality.

[0143] 5. In the embodiment of the present invention, obtaining a gradient value based on actual intensity information and initial intensity information specifically includes: obtaining an error value between the actual intensity information and the initial intensity information; and obtaining a gradient value using a preset formula based on the error value and discretized phase information.

[0144] The preset formula is:

[0145] CF=∑(I i -I0) 2 ;

[0146]

[0147] Among them, I0 is the initial intensity information, I i is the actual intensity information, CF is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value. By calculating the error between the actual intensity information and the initial light intensity information, we can determine whether the current phase reconstruction effect meets the requirements and make adjustments and optimizations.

[0148] 6. The embodiment of the present invention further provides a holographic mask information generating device, which has the same beneficial effects as the above-mentioned holographic mask information generating method, and will not be described in detail here.

[0149] 7. An embodiment of the present invention further provides an exposure device having the same beneficial effects as the above-mentioned method for generating holographic mask information, which will not be described in detail here.

[0150] The above is a detailed introduction to a holographic mask information generation method, device, exposure equipment and computer-readable storage medium disclosed in an embodiment of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention. Any modifications, equivalent replacements and improvements made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for generating holographic mask information, characterized in that: include: Obtaining initial intensity information of the wafer surface, and obtaining random phase information of the wafer surface based on the initial intensity information; The initial intensity information and random phase information are subjected to simulated propagation processing and discretization processing to obtain discretized phase information; The incident light modulated by the discrete phase information is filtered and propagated to the wafer surface, and the actual intensity information of the wafer surface is obtained; Obtaining a gradient value based on actual intensity information and initial intensity information; Determine whether the gradient value is less than or equal to a preset value; If so, outputting holographic mask information based on the discretized phase information and the preset amplitude value; If not, the discretized phase information is used as random phase information, and the initial intensity information and the random phase information are iteratively subjected to the process of simulated propagation processing and discretization processing.

2. The method for generating holographic mask information according to claim 1, wherein: The simulation propagation and discretization processing of the initial intensity information and random phase information include: acquiring an initial wavefront on the wafer surface based on initial intensity information and random phase information; Simulating the process of the initial wavefront propagating from the wafer surface to the holographic mask surface and obtaining a simulated wavefront; The simulated wavefront is discretized to obtain discrete phase information.

3. The method for generating holographic mask information according to claim 2, wherein: The process of simulating the propagation of the initial wavefront from the wafer surface to the holographic mask surface includes: using a preset simulation algorithm to simulate the propagation of the initial wavefront from the wafer surface to the holographic mask surface; The preset simulation algorithm is the plane wave angular spectrum method.

4. The method for generating holographic mask information according to claim 1, wherein: The filtering process specifically includes: Get the dimensions of the holographic mask; Setting an interval based on the dimension, and extracting a preset number of parameter values ​​within the interval; Set the total number of iterations, divide the number of iterations into multiple levels, determine the level of the current iteration and obtain the parameter value corresponding to the current iteration; Obtain the corresponding Gaussian filter based on the parameter value corresponding to the current iteration through the preset filtering algorithm; The modulated incident light is filtered using a Gaussian filter.

5. The method for generating holographic mask information according to claim 4, wherein: The preset filtering algorithm is: W(k)=exp[(-1 / 2)×(k / a) 2 ]; Where k is the spatial frequency, W(k) is the Gaussian filter function with k as the independent variable, and a is the parameter value corresponding to the current iteration.

6. The method for generating holographic mask information according to claim 1, wherein: Obtaining the gradient value based on the actual intensity information and the initial intensity information specifically includes: Obtain the error value between the actual intensity information and the initial intensity information; A gradient value is obtained by a preset formula based on the error value and the discretized phase information; The preset formula is: CF=∑(I i -I0) 2 ; Among them, I0 is the initial intensity information, I i is the actual intensity information, CF is the error between the actual intensity information and the initial intensity information, is the discretized phase information, δ is the gradient value; the preset value is 0.

03.

7. A holographic mask information generating device, characterized in that: The holographic mask information generating device comprises: Acquisition module: used to obtain initial intensity information of the wafer surface, and obtain random phase information of the wafer surface based on the initial intensity information; Processing module: used for performing simulation propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information; Simulation module: used to filter the incident light modulated by the discrete phase information and transmit it to the wafer surface, and obtain the actual intensity information of the wafer surface; Judgment module: obtains a gradient value based on the actual intensity information and the initial intensity information, and determines whether the gradient value is less than or equal to a preset value; Output module: used to determine whether to output holographic mask information based on the discretized phase information and the preset amplitude value based on the result of the judgment module.

8. An exposure device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the holographic mask information generation optimization method according to any one of claims 1 to 6.

9. A computer-readable storage medium, wherein: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the holographic mask information generating method according to any one of claims 1 to 6.

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