A holographic mask information generation optimization method, device and exposure equipment

Abstract

The present invention relates to the field of photolithography, and more particularly to a method, apparatus, and exposure device for optimizing holographic mask information generation. The method comprises: obtaining initial intensity information from a wafer surface, and obtaining initial phase information from the wafer surface based on the initial intensity information; subjecting the initial intensity information and initial phase information to simulated propagation processing and discretization to obtain discretized phase information; propagating incident light modulated by the discretized phase information 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 greater than a preset value; and if not, outputting holographic mask information based on the discretized phase information and a preset amplitude value. This method solves the problem of long time and low efficiency in the holographic mask information generation process.

Description

Technical Field

[0001] The present invention relates to the field of photolithography technology, and in particular to a method and device for optimizing holographic mask information generation and exposure equipment. Background Art

[0002] Holographic diffraction lithography uses the diffraction and interference effects of light to construct an aerial image to create integrated circuit layouts. A holographic mask is composed of a set of small holes that record all the information about the target pattern. After incident light is diffracted by the mask, the diffraction patterns produced by each hole "assemble" 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, which diffracts after passing through the holographic mask and forms an aerial image of the target pattern on the wafer, thereby transferring the target pattern to the wafer.

[0003] The core of holographic mask information generation lies in phase recovery, which can be solved using either iterative or non-iterative algorithms. Iterative algorithms continuously iterate and constrain phase values ​​until the updated phase hologram meets the requirements, and then output it. Non-iterative methods, on the other hand, perform a single solution based on given data and conditions. Existing iterative algorithms iterate the holographic mask information until the desired holographic mask phase information is obtained. This generation process is time-consuming and inefficient. Summary of the Invention

[0004] In order to solve the problem of long time and low efficiency in the generation process of holographic mask information, the present invention provides a holographic mask information generation optimization method, device and exposure equipment.

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

[0006] Acquiring initial intensity information of the wafer surface, and acquiring initial phase information of the wafer surface based on the initial intensity information;

[0007] Performing simulated propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information;

[0008] The incident light modulated by the discrete phase information propagates 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 greater than a preset value;

[0011] If not, 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 greater than a preset value further includes:

[0013] If so, the discretized phase information is used as the initial phase information, and the initial intensity information and the initial phase information are iteratively subjected to the process of simulating propagation processing and discretizing processing.

[0014] Preferably, assigning initial phase information to the wafer surface specifically includes: assigning initial phase information to the wafer surface through a Kramers-Kronig relationship;

[0015] The Kramers-Kronig relationship is as follows:

[0016] ;

[0017] ;

[0018] in, ;

[0019] The set plane includes vertical and parallel directions that are perpendicular to each other. Represents the horizontal component of the position coordinate, express The integral variable, The unit vector representing the horizontal component of the position coordinate, Represents the vertical component of the position coordinate, Represents the unit vector of the component in the vertical direction of the position coordinate, r is the sum of the orthogonal vectors of any coordinate point in the plane, r' represents the integral variable of r, I0 represents the initial intensity information, P represents the principal value of the Cauchy integral, and i represents the imaginary unit. represents the initial phase information, and G represents the initial wavefront on the wafer surface.

[0020] Preferably, performing simulated propagation processing and discretization processing on the initial intensity information and the initial phase information includes:

[0021] acquiring an initial wavefront on the wafer surface based on initial intensity information and initial phase information;

[0022] Simulating the process of the initial wavefront propagating from the wafer surface to the holographic mask surface and obtaining a simulated wavefront;

[0023] The simulated wavefront is discretized to obtain discrete phase information.

[0024] 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;

[0025] The preset simulation algorithm is the plane wave angular spectrum method.

[0026] Preferably, the incident light modulated by the discrete phase information propagates to the wafer surface, comprising:

[0027] Obtaining the intensity and phase of the incident light modulated by the discretized phase information;

[0028] Obtaining a modulated wavefront based on the intensity and phase of the modulated incident light;

[0029] 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 information of the wafer surface is obtained.

[0030] Preferably, obtaining the gradient value based on the actual intensity information and the initial intensity information specifically includes:

[0031] Obtain the error value between the actual intensity information and the initial intensity information;

[0032] A gradient value is obtained by a preset formula based on the error value and the discretized phase information;

[0033] The preset formula is:

[0034] ;

[0035] δ= ;

[0036] Among them, I0 is the initial intensity information, I i is the actual intensity information, is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value.

[0037] Preferably, outputting the holographic mask information based on the discretized phase information and the preset amplitude value specifically includes the following steps: multiplying the preset amplitude value by the discretized phase information and outputting the result as the holographic mask information.

[0038] In order to solve the above technical problems, the present invention provides another technical solution as follows: a holographic mask information generation and optimization device, the holographic mask information generation and optimization device comprising:

[0039] Acquisition module: used to obtain initial intensity information of the wafer surface, and obtain initial phase information of the wafer surface based on the initial intensity information;

[0040] 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;

[0041] Simulation module: used to propagate the incident light modulated by the discrete phase information to the wafer surface and obtain the actual intensity information of the wafer surface;

[0042] Judgment module: used to obtain a gradient value based on actual intensity information and initial intensity information, and to determine whether the gradient value is greater than a preset value;

[0043] 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.

[0044] 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 above holographic mask information generation optimization method.

[0045] Compared with the prior art, the method, device and exposure equipment for generating and optimizing holographic mask information provided by the present invention have the following beneficial effects:

[0046] 1. An embodiment of the present invention provides a method for optimizing holographic mask information generation, comprising: obtaining initial intensity information from a wafer surface, and obtaining initial phase information from the wafer surface based on the initial intensity information; performing simulated propagation processing and discretization on the initial intensity information and initial phase information to obtain discretized phase information; propagating incident light modulated by the discretized phase information 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 greater than a preset value; and if not, outputting holographic mask information based on the discretized phase information and a preset amplitude value. Compared to existing iterative algorithms, this embodiment, by assigning initial intensity information to the wafer surface, eliminates the need for a complex iterative process, thereby reducing the time required to generate holographic mask information.

[0047] 2. The embodiment of the present invention provides that initial phase information is assigned to the wafer surface, specifically including: assigning initial phase information to the wafer surface through the Kramers-Kronig relationship;

[0048] The Kramers-Kronig relationship is as follows:

[0049] ;

[0050] ;

[0051] The set plane includes a vertical direction and a parallel direction perpendicular to each other. Represents the horizontal component of the position coordinate, express The integral variable, The unit vector representing the horizontal component of the position coordinate, Represents the vertical component of the position coordinate, Represents the unit vector of the component in the vertical direction of the position coordinate, r is the sum of the orthogonal vectors of any coordinate point in the plane, r' represents the integral variable of r, I0 represents the initial intensity information, P represents the principal value of the Cauchy integral, and i represents the imaginary unit. Denotes the initial phase information, and G represents the initial wavefront on the wafer surface. Assigning initial phase information to the wafer surface through the Kramers-Kronig relationship reduces subsequent iterations and, in turn, reduces the time spent generating holographic mask information, thereby improving its efficiency.

[0052] 3. The present invention simulates propagation and discretizes initial intensity and phase information, including: obtaining an initial wavefront on the wafer surface based on the initial intensity and 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.

[0053] 4. The process of simulating the propagation of the initial wavefront from the wafer surface to the holographic mask surface in the embodiment of the present invention includes: using a preset simulation algorithm to simulate the propagation of the initial wavefront from the wafer surface to the holographic mask surface.

[0054] The preset simulation algorithm is a plane wave angular spectrum method. The preset simulation algorithm can simulate the process of the initial wavefront propagating from the wafer surface to the holographic mask surface in an efficient and simple manner.

[0055] 5. In an embodiment of the present invention, the method of transmitting incident light modulated by discrete phase information to the wafer surface includes: obtaining the intensity and phase of the incident light modulated by the discrete phase information; obtaining a modulated wavefront based on the intensity and phase of the modulated incident light; and simulating the process of the modulated wavefront propagating from the holographic mask to the wafer surface based on a Rayleigh-Sommerfeld diffraction algorithm, thereby obtaining actual intensity information on the wafer surface. The Rayleigh-Sommerfeld diffraction algorithm accurately simulates the propagation of the modulated wavefront from the holographic mask to the wafer surface, and accurately obtains the actual light intensity on the wafer surface during the simulation.

[0056] 6. In the embodiment of the present invention, obtaining a gradient value based on actual intensity information and initial intensity information specifically includes:

[0057] Obtain the error value between the actual intensity information and the initial intensity information;

[0058] A gradient value is obtained by a preset formula based on the error value and the discretized phase information;

[0059] The preset formula is:

[0060] ;

[0061] δ= ;

[0062] Among them, I0 is the initial intensity information, I i is the actual intensity information, 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, it is possible to quickly determine whether the discretized phase information on the current holographic mask can accurately reconstruct the incident light and whether the effect meets the requirements.

[0063] 7. An embodiment of the present invention further provides a holographic mask information generation and optimization device, which has the same beneficial effects as the above-mentioned holographic mask information generation and optimization method, and will not be described in detail here.

[0064] 8. An embodiment of the present invention further provides a holographic mask exposure device, which has the same beneficial effects as the above-mentioned holographic mask information generation optimization method, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The figure is a flow chart of a method for optimizing holographic mask information generation provided by an embodiment of the present invention.

[0066] 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 holographic mask information generation optimization method provided by an embodiment of the present invention.

[0067] Figure 3 It is a structural diagram of a holographic mask information generation and optimization device provided by an embodiment of the present invention.

[0068] Description of the accompanying drawings:

[0069] 1. Holographic mask information generation and optimization device;

[0070] 11. Acquisition module; 12. Processing module; 13. Simulation module; 14. Judgment module; 15. Output module. DETAILED DESCRIPTION

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] Photolithography is a key process in the production of integrated circuits in the semiconductor industry. During photolithography, users typically use incident light to process the surface of a wafer or silicon chip 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. Using a suitable holographic mask, highly complex patterns can be formed on a silicon wafer that would be impossible to create using traditional planar masks. It should be understood that the incident light refers to light emitted by specialized light sources, such as extreme ultraviolet (EUV), deep ultraviolet (DUV), or argon fluoride (ArF).

[0077] The core of the phase holographic mask generation method is phase recovery, which can be solved by iterative algorithms and non-iterative algorithms. The iterative algorithm continuously iterates and constrains the phase value until the updated phase hologram meets the requirements and then outputs it. The non-iterative method solves the problem once based on the given data and conditions, so the phase reconstruction quality is not as good as the iterative algorithm. Compared with the non-iterative algorithm, the iterative algorithm is an adaptive algorithm that can adjust the number of iterations and stopping criteria as needed to achieve better results. In addition, the iterative algorithm can ensure that after reaching a certain number of iterations, the error can gradually converge to a smaller value to achieve higher accuracy. However, the existing technology has the problem of long time and low efficiency in the process of using iterative algorithms to generate holographic mask information.

[0078] To solve the above problem, please refer to Figure 1 The embodiment of the present invention provides a method for optimizing the generation of holographic mask information, comprising the following steps:

[0079] S1, obtaining initial intensity information of the wafer surface, and obtaining initial phase information of the wafer surface according to the initial intensity information;

[0080] S2, performing simulation propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information;

[0081] S3, the incident light modulated by the discrete phase information propagates to the wafer surface, and the actual intensity information of the wafer surface is obtained;

[0082] S4, obtaining a gradient value based on the actual intensity information and the initial intensity information;

[0083] S5, determining whether the gradient value is greater than a preset value;

[0084] S6, if not, outputting holographic mask information based on the discretized phase information and the preset amplitude value;

[0085] S7: If yes, the discretized phase information is used as the initial phase information, and the initial intensity information and the initial phase information are iteratively subjected to the process of simulating propagation processing and discretizing processing.

[0086] It should be understood that in the prior art, iteration is performed based on an iterative algorithm until holographic mask information is output. This results in a complex iteration process and a slow iteration speed. In this embodiment, initial intensity information of the wafer surface is first obtained. Furthermore, initial phase information of the wafer surface is obtained based on the initial intensity information of the wafer surface. Specifically, the initial phase information of the wafer surface is calculated by the designer based on the initial intensity information and the Kramers-Kronig relationship and then assigned to the wafer surface. The initial intensity information and initial phase information are then discretized to obtain discretized intensity information and discretized phase information. In this case, the discretized intensity information is set to a unit value, while the discretized phase information can be used as the phase value of the pixels distributed on the holographic mask. Furthermore, after the incident light is modulated by the holographic mask and propagates to the wafer surface, actual intensity information is obtained. A gradient value is then obtained based on the actual intensity information and the initial intensity information. By comparing the gradient value with a preset value, it is determined whether the discretized phase information and the preset amplitude value should be output as holographic mask information. Compared with the existing iterative algorithm, this embodiment does not require a complicated iterative process by giving initial intensity information to the wafer surface, thereby reducing the time spent on the generation process of the holographic mask information.

[0087] Specifically, obtaining the initial phase information of the wafer surface specifically includes: obtaining the initial phase information through the Kramers-Kronig relationship and the initial intensity information, and assigning the initial phase information to the wafer surface. The Kramers-Kronig relations are a set of mathematical relations that describe the relationship between the absorption and refraction of light in linear, dissipative media. The Kramers-Kronig relations are based on the analysis of the complex refractive index or the complex dielectric constant, linking the correlation between the real part (absorption) and the imaginary part (refraction). Specifically, the Kramers-Kronig relations show that the absorption spectrum (real part) and the corresponding refraction spectrum (imaginary part) of a medium are related through Fourier transform.

[0088] It should be understood that the Kramers-Kronig relationship can be used to assign initial phase information to the wafer surface. This relationship is used to calculate the phase information of the wafer surface based on the transmittance information of the wafer surface, using the relationship between the optical refractive index and reflectivity. High-quality reconstructed images in holograms require modulating the light waves using a holographic mask with appropriate scale and proportion. Assigning initial phase information to the wafer surface using the Kramers-Kronig relationship reduces subsequent iterations and, in turn, the time spent generating holographic mask information, thereby improving its efficiency.

[0089] Specifically, the Kramers-Kronig relationship is as follows:

[0090] ;

[0091] ;

[0092] in, ;

[0093] The set plane includes vertical and parallel directions that are perpendicular to each other. Represents the horizontal component of the position coordinate, express The integral variable, The unit vector representing the horizontal component of the position coordinate, Represents the vertical component of the position coordinate, Represents the unit vector of the component in the vertical direction of the position coordinate, r is the sum of the orthogonal vectors of any coordinate point in the plane, r' represents the integral variable of r, I0 represents the initial intensity information, P represents the principal value of the Cauchy integral, and i represents the imaginary unit. represents the initial phase information, and G represents the initial wavefront on the wafer surface.

[0094] Furthermore, in the above step S2, the simulation propagation processing and discretization processing of the initial intensity information and the initial phase information specifically include:

[0095] S21, acquiring an initial wavefront on the wafer surface based on the initial intensity information and the initial phase information;

[0096] S22, simulating a process in which the initial wavefront propagates from the wafer surface to the holographic mask surface, and obtaining a simulated wavefront;

[0097] S23, discretizing the simulated wavefront to obtain discrete phase information.

[0098] It should be understood that a wavefront refers to the geometric positions of all points with the same vibration phase at the same moment. During wave propagation, these points with the same 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 the phase and intensity of the wave. The vibration state (phase) of each point on the wavefront is the same, meaning that the wavefront can be viewed as an isophase surface with the same phase. However, the intensity or energy density of the wave may vary at different locations on the wavefront. Therefore, once the initial intensity and initial 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 initial phase information.

[0099] It should be noted that the holographic mask includes not only the amplitude information of the pattern, but also the phase information of the pattern. The discretized intensity information is usually set to a unit value, while the discretized phase information is used as the phase value of each pixel on the holographic mask pattern. When incident light is irradiated on the surface of the holographic mask, the discretized phase information on the holographic mask can be used to phase modulate the incident light.

[0100] 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. During the recording stage, the discretized phase information serves as the phase value for each pixel on the holographic mask's pattern. During this process, the holographic mask records both discrete intensity information and discrete phase information. During the reconstruction stage, as incident light passes through the holographic mask, it interacts with the pattern recorded on the holographic mask. The phase of the incident light changes under the phase modulation of the holographic mask, and the pattern recorded on the holographic mask is reconstructed, thereby producing a three-dimensional image of the object. It should be understood that 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. Thus, a correspondence is generated between the intensity distribution of the incident light and the pattern, realizing the process of recording and reconstructing object information.

[0101] 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.

[0102] 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. Optional.

[0103] Preferably, the preset simulation algorithm is the plane wave angular spectrum method. Specifically, the initial wavefront of the wafer surface set at plane Σ0 with z=0 can be written as , when it propagates to the holographic mask surface at a distance of z, the simulated wavefront on the holographic mask plane can be written as:

[0104]

[0105] in, It means The Fourier transform of represents the spatial frequency of the complex amplitude of the wavefront, represents a unit space circular function, with a value of 1 within a radius of 1 and 0 elsewhere, and k^2 > kx^2 + ky^2. It should be understood that the plane wave 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, thereby obtaining a simulated wavefront from the initial wavefront propagating to the holographic mask surface. The plane wave angular spectrum method has the advantages of a wide range of applications, simple numerical calculations, high accuracy, and short computation time. The plane wave angular spectrum method can be used to simulate the process of the initial wavefront propagating from the wafer surface to the holographic mask surface efficiently and simply.

[0106] Furthermore, in the above step S3, the incident light modulated by the discrete phase information propagates to the wafer surface, specifically including:

[0107] S31, acquiring the intensity and phase of the incident light modulated by the discretized phase information;

[0108] S32, obtaining a modulated wavefront based on the intensity and phase of the modulated incident light;

[0109] S33, based on the Rayleigh-Sommerfeld diffraction algorithm, simulates the process of the modulated wavefront propagating from the holographic mask to the wafer surface, and obtains the actual intensity information of the wafer surface.

[0110] 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):

[0111]

[0112] Where d represents the distance from the spherical wave convergence point to the mask surface, and the wavefront information of the incident light after passing through the mask is The wavefront on the wafer surface after passing the diffraction distance z distributed. represents the spatial coordinates of the mask surface, represents the spatial coordinate on the wafer surface, j represents the imaginary unit, and k represents the wave vector. It should be understood that Rayleigh-Sommerfeld diffraction can conveniently simulate the process of incident light propagating from the holographic mask to the wafer surface. Specifically, after the incident light is modulated by the holographic mask, the modulated wavefront can be obtained by obtaining its modulated intensity and phase. The Rayleigh-Sommerfeld diffraction algorithm is then used to simulate the propagation of the modulated wavefront from the holographic mask to the wafer surface, and the actual light intensity on the wafer surface during the simulation is accurately obtained.

[0113] 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.

[0114] As another possible implementation, when the gradient value is greater than a preset value, meaning it does not meet the standard, the discretized phase information on the current wafer surface needs to be retained. A processed wavefront is then obtained based on the known initial intensity information and discretized phase information. This wavefront is then used as the initial wavefront and the process from steps S2 to S7 is iterated. It should be noted that during the iterative process using the processed wavefront as the initial wavefront, since the specific parameter values ​​of each initial wavefront are different, each discretization process yields different discretized phase information, allowing the discretized phase information to be gradually adjusted. The iterated discretized phase information is then used as the phase value for each pixel in the pattern on the holographic mask. When the incident light passes through the holographic mask and is adjusted by the iterative discretized phase information, a more precise and accurate reconstruction result is achieved. Specifically, the error between the actual intensity information of the incident light propagating onto the wafer surface, simulated by the iterative discretized phase information, and the initial light intensity information is continuously reduced. Therefore, the iterative process not only improves the efficiency of holographic mask generation, but also ensures that the generated holographic mask has high reconstruction efficiency and accuracy for the incident light.

[0115] Specifically, the value of the initial intensity information is the same in each iteration, that is, each iteration uses the initial intensity information of the wafer surface obtained in step S1. However, what actually changes in 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 The discretized phase information is As the initial phase information, the initial intensity information and initial phase information are simulated and propagated and discretized to obtain the discretized phase information after the first iteration , and 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 , that is, to discretize the phase information The discretized phase information obtained by the second iteration of the simulated propagation processing and discretization processing with the initial intensity information .

[0116] 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 , continue the third iteration process until the gradient value is less than or equal to the preset value, and the iteration process is completed.

[0117] Specifically, in the above step S4, obtaining the gradient value based on the actual intensity information and the initial intensity information specifically includes:

[0118] Obtain the error value between the actual intensity information and the initial intensity information;

[0119] A gradient value is obtained by a preset formula based on the error value and the discretized phase information;

[0120] The preset formula is:

[0121] ;

[0122] δ= ;

[0123] Among them, I0 is the initial intensity information, I i is the actual intensity information, is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value.

[0124] It should be understood that the initial intensity information is a reference value obtained based on the surface information of the wafer itself. The actual intensity information, on the other hand, reflects the propagation and diffraction characteristics. It can reflect 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 quickly determine whether the discretized phase information on the current holographic mask can accurately reconstruct the incident light and meet the requirements. Based on this determination, the holographic mask can be further adjusted and optimized.

[0125] Further, see Figure 1 , after obtaining the gradient value, it further includes:

[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] In step S6, outputting holographic mask information based on the discretized phase information and the preset amplitude value specifically includes the following steps: setting the preset amplitude value to unity, multiplying the preset amplitude value by the discretized phase information, and outputting the result as the holographic mask information. For example, if the gradient value is equal to the preset value, the discretized phase information can be output. Setting the preset amplitude value to 1 allows the discretized phase information to be output as the holographic mask information. It should be noted that the amplitude value described above is only one possible implementation and is not intended to be limiting.

[0128] Please combine Figure 1 and Figure 3 In order to solve the above technical problems, the present invention further provides a holographic mask information generation and optimization device 1, the holographic mask information generation and optimization device 1 comprising:

[0129] Acquisition module 11: used to acquire initial intensity information of the wafer surface, and acquire initial phase information of the wafer surface based on the initial intensity information;

[0130] 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;

[0131] Simulation module 13: used to propagate the incident light modulated by the discrete phase information to the wafer surface and obtain actual intensity information of the wafer surface;

[0132] Determination module 14: used to obtain a gradient value based on the actual intensity information and the initial intensity information, and determine whether the gradient value is greater than a preset value;

[0133] 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.

[0134] The holographic mask information generation and optimization device 1 provided in this embodiment has the same beneficial effects as the above-mentioned holographic mask information generation and optimization method, which will not be described in detail here.

[0135] In order to solve the above technical problems, the present invention further provides an exposure device, which includes: 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.

[0136] The exposure device provided by the embodiment of the present invention has the same beneficial effects as the above-mentioned method for optimizing the generation of holographic mask information, which will not be described in detail here.

[0137] The above is a detailed introduction to a holographic mask information generation optimization method, device and exposure equipment disclosed in an embodiment of the present invention. Specific examples are used in this article 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 general technical personnel in this field, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. 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 holographic mask information generation optimization method, characterized in that: include: Acquiring initial intensity information of the wafer surface, and acquiring initial phase information of the wafer surface based on the initial intensity information; Performing simulated propagation processing and discretization processing on the initial intensity information and the initial phase information to obtain discretized phase information; The incident light modulated by the discrete phase information propagates 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 greater than a preset value; If not, outputting holographic mask information based on the discretized phase information and the preset amplitude value; If so, the discretized phase information is used as the initial phase information, and the initial intensity information and the initial phase information are iteratively subjected to the process of simulating propagation processing and discretizing processing.

2. The holographic mask information generation and optimization method according to claim 1, wherein: Assigning initial phase information to the wafer surface specifically includes: obtaining the initial phase information of the wafer surface through the Kramers-Kronig relationship; The expression of the Kramers-Kronig relationship is as follows: ； ； in, ; The set plane includes a vertical direction and a parallel direction perpendicular to each other. Represents the horizontal component of the position coordinate, express The integral variable, The unit vector representing the horizontal component of the position coordinate, Represents the vertical component of the position coordinate, Represents the unit vector of the component in the vertical direction of the position coordinate, r is the sum of the orthogonal vectors of any coordinate point in the plane, r' represents the integral variable of r, I0 represents the initial intensity information, P represents the principal value of the Cauchy integral, and i represents the imaginary unit. represents the initial phase information, and G represents the initial wavefront on the wafer surface.

3. The holographic mask information generation and optimization method according to claim 1, wherein: The simulation propagation processing and discretization processing of the initial intensity information and the initial phase information include: acquiring an initial wavefront on the wafer surface based on initial intensity information and initial 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.

4. The method for optimizing holographic mask information generation according to claim 3, 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.

5. The holographic mask information generation and optimization method according to claim 1, wherein: The incident light modulated by the discrete phase information propagates to the wafer surface including: Obtaining the intensity and phase of the incident light modulated by the discretized phase information; Obtaining a modulated wavefront based on the intensity and phase of the modulated incident light; 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 information of the wafer surface is obtained.

6. The holographic mask information generation and optimization method 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: ； δ= ; Among them, I0 is the initial intensity information, I i is the actual intensity information, is the error between the actual intensity information and the initial intensity information, is the discretized phase information, and δ is the gradient value.

7. The method for optimizing holographic mask information generation according to claim 1, wherein: Outputting the holographic mask information based on the discretized phase information and the preset amplitude value specifically includes the following steps: multiplying the preset amplitude value by the discretized phase information and outputting the result as the holographic mask information.

8. A holographic mask information generation and optimization device, characterized in that: The holographic mask information generation and optimization device comprises: Acquisition module: used to obtain initial intensity information of the wafer surface, and obtain initial 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 propagate the incident light modulated by the discrete phase information to the wafer surface and obtain the actual intensity information of the wafer surface; Judgment module: used to obtain a gradient value based on actual intensity information and initial intensity information, and to determine whether the gradient value is greater than 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.

9. 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 7.

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