Mask imitation image acquisition method and device, exposure equipment and medium

Abstract

The invention relates to the technical field of computational lithography, and discloses a method and a device for acquiring a mask simulation image, exposure equipment and a medium, and the method comprises the following steps of: firstly, performing analog simulation on a diffraction image of a light beam on a corresponding plane after the light beam is propagated by a preset propagation distance through acquired ideal wavefront, spatial frequency of the light beam and the preset propagation distance; and then, the diffraction image is disturbed in a predetermined disturbance mode to simulate the influence of the unbalanced distribution of the refractive index on holographic imaging, so that a simulation image is obtained. According to the embodiment, through the mode, the simulation image can be simply and quickly simulated, and the effectiveness of the simulation image in time and space is reflected. According to the mode, the influence degree of uneven refractive index distribution of the current immersion liquid on imaging can be conveniently and directly judged based on the finally obtained simulation image, so that whether an image with higher resolution can be obtained by utilizing the current immersion liquid with uneven refractive index distribution or not can be quickly determined, and the working efficiency is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of computational lithography, and in particular to a method, device, exposure equipment and medium for acquiring a mask simulation image. Background Art

[0002] Immersion lithography is one of the important ways to improve the resolution limit in traditional projection lithography. In the theory of holographic image reconstruction, there are two main ways to improve the image reconstruction resolution. One is to reduce the wavelength λ of the laser illumination; the other is to increase the numerical aperture NA of the recording camera. Adding an immersion liquid with a refractive index n>1 between the recorded object and the recording camera can be equivalently regarded as reducing the wavelength to λ / n or increasing the numerical aperture to n·NA, thereby achieving the effect of improving the resolution of the reconstructed image.

[0003] However, when applying the above theory to engineering practice, due to factors such as uneven distribution of immersion liquid temperature and uneven flow rate, the distribution of refractive index n in the immersion system cannot be uniform everywhere, which may lead to an increase in the error between lithography experimental imaging and simulation imaging using scalar diffraction theory. Therefore, in the simulation of immersion holographic lithography engineering, whether the current immersion liquid with uneven refractive index distribution can be used for imaging to improve the resolution of the image has become an extremely critical issue. Summary of the invention

[0004] In view of this, the present invention provides a method, device, exposure equipment and medium for acquiring a mask simulation image, so as to solve the problem of being unable to judge whether the current immersion liquid is imageable.

[0005] In a first aspect, the present invention provides a method for acquiring a mask simulation image, the method being applied to an exposure operation of an immersion holographic mask in a chip manufacturing process, the method comprising:

[0006] The ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and the preset propagation distance are obtained; based on the ideal wavefront, the spatial frequency and the preset propagation distance, the diffraction image corresponding to the light beam after propagating the preset propagation distance is simulated; the diffraction image is disturbed by using a predetermined disturbance method to obtain a simulation image of the holographic mask.

[0007] The method for acquiring the mask simulation image provided in this embodiment first obtains the diffraction image of the light beam on the corresponding plane after the light beam propagates the preset propagation distance by acquiring the ideal wavefront, the spatial frequency of the light beam and the preset propagation distance. Then, the diffraction image is disturbed by using the predetermined wave aberration function as a disturbance factor to simulate the uneven distribution of the refractive index, thereby obtaining a simulated image. This embodiment can simulate the simulated image simply and quickly through the above method, reflecting its effectiveness in time and space. Based on the simulated image finally obtained, it is also convenient to directly judge the degree of influence of the uneven distribution of the refractive index of the current immersion liquid on the imaging, so as to quickly determine whether the current immersion liquid can be used to obtain higher resolution imaging, thereby improving work efficiency.

[0008] In some optional implementations, the diffraction image is disturbed by using a predetermined disturbance method to obtain a holographic mask simulation image, including:

[0009] The predetermined first-wave aberration function is used to simulate the disturbance of the diffraction image caused by the immersion liquid to obtain a simulated image; the first-wave aberration function is adjusted to a second-wave aberration function; the second-wave aberration function is used to simulate the disturbance of the simulated image caused by the unevenly distributed refractive index to obtain a holographic mask simulated image.

[0010] The method for acquiring a mask simulation image provided in this embodiment takes into account the influence of the immersion liquid on the light beam and the influence of the uneven refractive index distribution on the light beam through two disturbances, thereby making the final simulation image more realistic and accurate.

[0011] In some optional embodiments, determining the first wave aberration function includes:

[0012] The phase difference that obeys the preset distribution information is taken as an independent variable, where the phase difference is the phase difference between the ideal wavefront and the actual wavefront of the mask plane; based on the phase difference and the spatial frequency, the first wave aberration function is determined.

[0013] In some optional embodiments, adjusting the first wave aberration function to the second wave aberration function includes:

[0014] A refractive index deviation corresponding to predetermined target distribution information is obtained; a phase difference of the mask plane is adjusted based on the refractive index deviation and a preset propagation distance, and a spatial frequency of the light beam is adjusted based on a preset ideal refractive index and a preset propagation distance; a second wave aberration function is generated based on the adjusted phase difference and the adjusted spatial frequency.

[0015] The method for acquiring the mask simulation image provided in this embodiment adjusts the refractive index deviation and the spatial frequency of the light beam so that the second wave aberration function can better simulate the uneven refractive index distribution, thereby making the simulation image generated after the disturbance of the second wave aberration function more realistic.

[0016] In some optional implementations, the target distribution information is determined by:

[0017] Acquire the immersion liquid temperature fluctuation value; and determine the target distribution information corresponding to the immersion liquid temperature fluctuation value from the pre-built mapping relationship.

[0018] In some optional embodiments, based on the ideal wavefront, the spatial frequency and the preset propagation distance, simulating the diffraction image corresponding to the light beam after propagating the preset propagation distance includes:

[0019] Using Rayleigh-Sommerfeld diffraction theory, the diffraction pattern is simulated based on the ideal wavefront, spatial frequency and preset propagation distance.

[0020] In some optional implementations, after perturbing the diffraction image using a predetermined perturbation method to obtain a holographic mask simulation image, the method further includes:

[0021] The eligibility of the holographic mask simulation image is judged based on the image clarity.

[0022] In a second aspect, the present invention provides a device for acquiring a mask simulation image, which is applied to an immersion holographic exposure operation in a chip manufacturing process. The device includes a data acquisition module, an image simulation module and an image acquisition module.

[0023] The data acquisition module is used to obtain the ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and the preset propagation distance; the image simulation module is used to simulate the diffraction image corresponding to the light beam after propagating the preset propagation distance based on the ideal wavefront, spatial frequency and preset propagation distance; the image acquisition module is used to perturb the diffraction image using a predetermined perturbation method to obtain a holographic mask simulation image.

[0024] In a third aspect, the present invention provides an exposure device for use in a chip preparation process, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, computer instructions being stored in the memory, and the processor executing the method for acquiring a mask simulation image of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0025] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to cause a computer to execute the method for acquiring a mask simulation image according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a schematic flow chart of a method for acquiring a mask simulation image according to an embodiment of the present invention;

[0028] Figure 2 is a schematic flow chart of another method for acquiring a mask simulation image according to an embodiment of the present invention;

[0029] Figure 3 is a holographic mask simulation image corresponding to the immersion liquid temperature fluctuation amplitude of 1mK according to an embodiment of the present invention;

[0030] Figure 4 is a holographic mask simulation image corresponding to the immersion liquid temperature fluctuation amplitude of 10mK according to an embodiment of the present invention;

[0031] Figure 5 is a flowchart of another method for acquiring a mask simulation image according to an embodiment of the present invention;

[0032] Figure 6 is a structural block diagram of a device for acquiring a mask simulation image according to an embodiment of the present invention;

[0033] Figure 7 It is a schematic diagram of the hardware structure of the exposure device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0035] In traditional projection lithography, adding immersion liquid is one of the important means to improve etching resolution. In traditional projection lithography systems, since a complex lens system is added between the traditional mask and the wafer, and the thickness of the immersion liquid in projection lithography is thin, the effect of the uneven distribution of refractive index on the imaging quality can be almost ignored. However, in holographic diffraction lithography, since the complex lens system is replaced by a thick layer of immersion liquid, the effect of uneven distribution of refractive index on the imaging quality of holographic lithography cannot be ignored. Therefore, whether the current immersion liquid can be used for imaging and how much influence its uneven distribution of refractive index has on imaging are problems that need to be solved at present. To this end, an embodiment of the present invention provides a method for acquiring a mask simulation image, which simulates the uneven distribution of refractive index in the diffraction process by means of disturbance, thereby simulating the image after disturbance, that is, the simulation image, and then judging the influence of the uneven distribution of refractive index of the current immersion liquid on the imaging quality through the simulation image, and judging whether the current immersion liquid can be used for imaging based on this.

[0036] According to an embodiment of the present invention, an embodiment of a method for acquiring a mask simulation image is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0037] In this embodiment, a method for acquiring a mask simulation image is provided. The method is applied to an exposure operation of an immersion holographic mask in a chip manufacturing process, and can be specifically used in an exposure device. Figure 1 FIG. 4 is a flow chart of a method for obtaining a mask simulation image according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0038] Step S101, obtaining an ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and a preset propagation distance.

[0039] Specifically, the ideal wavefront is the wavefront corresponding to when the light beam is irradiated onto the mask plane. The mask plane here is the ideal mask plane ignoring the manufacturing error of the mask plane itself.

[0040] Specifically, the spatial frequency of the light beam is related to the wavelength, and the relationship between the two is k=2π / λ, where k is the spatial frequency and λ is the wavelength.

[0041] Specifically, the preset propagation distance is not specifically limited here, and those skilled in the art can determine it according to the resolution of the diffraction image.

[0042] Step S102, based on the ideal wavefront, the spatial frequency and the preset propagation distance, simulate the diffraction image corresponding to the light beam after propagating the preset propagation distance.

[0043] Specifically, the preset propagation distance is much greater than the wavelength of the light beam.

[0044] For example, the mask plane Σ is a plane at z=0 in space, and a light beam with a wavelength of λ propagates upward from the negative semi-axis of the z-axis (upward propagation means propagation in the direction of the positive semi-axis of the z-axis). When propagating to the mask plane Σ, the ideal wavefront U corresponding to the light beam at the mask plane Σ is obtained. Assuming that the propagation medium is air with a constant refractive index n of 1, according to the classical scalar diffraction theory, after the ideal wavefront U propagates a distance z0 (i.e., a preset propagation distance) in the positive direction of the z-axis, it can be imaged in the z=z0 plane, and the image formed is the diffraction image. Therefore, the diffraction image obtained in this step is the image corresponding to the light beam propagating in air with a uniform refractive index distribution.

[0045] For example, the Rayleigh-Sommerfeld diffraction theory can be used to simulate the diffraction image corresponding to the beam propagating the preset propagation distance based on the ideal wavefront, spatial frequency and preset propagation distance. The diffraction integral formula (also known as the Rayleigh-Sommerfeld formula) is as follows:

[0046]

[0047] Among them, U(x,y,z0) is the diffraction image of the z=z0 plane, U(ξ,η,0) is the ideal wavefront of the z=0 plane, k is the spatial frequency of the light beam, and G is the Green's function.

[0048] Among them, the Green function G is:

[0049]

[0050] Among them, i is the imaginary unit, r is the distance function, and the distance function r is:

[0051] r(ξ,η,x,y,z)=[(x-ξ) 2 +(y-η) 2 +z 2 ] 1 / 2

[0052] Step S103, disturbing the diffraction image using a predetermined disturbance method to obtain a holographic mask simulation image.

[0053] Specifically, the predetermined disturbance mode is used to simulate the influence of uneven refractive index distribution of the immersion liquid on the imaging quality. The holographic mask simulation image obtained after the disturbance is the image corresponding to the light beam propagating in the immersion liquid with uneven refractive index distribution.

[0054] For example, the predetermined perturbation method may be to perturb the diffraction image using a wave aberration function, or to perturb the diffraction image using Maxwell's equations. This embodiment does not specifically limit the perturbation method, and those skilled in the art may select any achievable perturbation method.

[0055] The method for acquiring the mask simulation image provided by the present embodiment first obtains the ideal wavefront, the spatial frequency of the light beam and the preset propagation distance, and obtains the diffraction image of the light beam on the corresponding plane after the preset propagation distance. Then, the diffraction image is disturbed by using a predetermined wave aberration function as a disturbance factor to simulate the uneven distribution of the refractive index, thereby obtaining a simulation image. The present embodiment can simulate the simulation image simply and quickly in the above manner, which reflects its effectiveness in time and space.

[0056] In addition, considering the accuracy requirements of the lithography exposure process for each exposure operation, it is required that the influence of the uneven distribution of the refractive index of the current immersion liquid on the imaging be simulated before each exposure is performed, and the exposure operation can be performed only when the simulation requirements are met. Therefore, the simulated image finally obtained by the embodiment of the present invention can be directly based on the degree of influence of the uneven distribution of the refractive index of the current immersion liquid on the imaging, so as to quickly determine whether the current immersion liquid can be used to obtain a higher resolution imaging according to the degree of influence, thereby improving the exposure efficiency of the lithography process, ensuring the process accuracy of each exposure operation, and improving the lithography yield.

[0057] In this embodiment, a method for acquiring a mask simulation image is provided. The method is applied to an exposure operation of an immersion holographic mask in a chip manufacturing process, and can be specifically used in an exposure device. Figure 2 FIG. 4 is a flow chart of a method for obtaining a mask simulation image according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0058] Step S201, obtaining the ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and the preset propagation distance. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0059] Step S202, based on the ideal wavefront, spatial frequency and preset propagation distance, simulate the diffraction image corresponding to the light beam after propagating the preset propagation distance. Figure 1 Step S102 of the illustrated embodiment will not be described in detail here.

[0060] Step S203, disturbing the diffraction image using a predetermined disturbance method to obtain a holographic mask simulation image.

[0061] Specifically, the above step S203 includes:

[0062] Step S2031: using a predetermined first-wave aberration function to simulate the disturbance of the immersion liquid on the diffraction image, to obtain a simulated image.

[0063] Specifically, the diffraction image is the image corresponding to the light beam propagating in the air with a uniform refractive index distribution. In the immersion holographic mask imaging process, there is an immersion liquid with a refractive index n>1 between the recorded object and the recording camera. Therefore, as the light beam propagation medium changes, the quality of the final holographic imaging is also affected. Therefore, this embodiment uses the first wave aberration function to disturb the diffraction image, and converts the influence of the light beam propagating in the immersion liquid on the holographic imaging quality into the influence of the uneven mask plane on the holographic imaging quality when propagating in the air. Thereby, the simulated image obtained by the first wave aberration perturbation can be closer to the holographic imaging under the condition of uniform immersion liquid, thereby achieving the purpose of effective simulation. It should be noted that the influence of the immersion liquid on the holographic imaging quality here refers to the influence of the immersion liquid on the holographic imaging quality under the condition of uniform refractive index distribution.

[0064] Based on the above inference, the influence of the error between the actual mask plane and the ideal mask plane on the holographic imaging is equivalent to replacing the influence of the immersion liquid on the holographic imaging. Therefore, in this embodiment, the error between the actual mask plane and the ideal mask plane is represented by the first wave aberration function, and the first wave aberration function is used to perturb the diffraction image obtained in step S202, so that the final simulation result is closer to the real image.

[0065] In an optional embodiment, the method for determining the first wave aberration function comprises the following steps:

[0066] Step a1: taking the phase difference that complies with preset distribution information as an independent variable.

[0067] Specifically, the preset distribution information is a uniform distribution or a Gaussian distribution expected to be zero.

[0068] Specifically, the phase difference is the phase difference between the ideal wavefront and the actual wavefront of the mask plane.

[0069] Exemplarily, in this embodiment, the phase difference caused by the unevenness of the mask plane is taken as a random variable, and the random variable obeys a uniform distribution or a Gaussian distribution with an expected value of 0.

[0070] Step a2, determining a first wave aberration function based on the phase difference and the spatial frequency.

[0071] Exemplarily, the first wave aberration function in this embodiment is e ikΔθ , where Δθ is the independent variable of the function, i is the imaginary unit, and k is the spatial frequency of the light beam.

[0072] The specific implementation method of using the first wave aberration function to perturb the diffraction image and obtain the actual wavefront image is as follows:

[0073]

[0074] Among them, U(x,y,z0) ′ For simulated images, e ikΔθ is the first wave aberration function.

[0075] This embodiment describes the influence of the mask plane phase difference Δθ on the holographic imaging quality through the above integral expression.

[0076] Step S2032: adjusting the first wave aberration function to a second wave aberration function.

[0077] In an optional embodiment, the above step S2032 includes:

[0078] Step b1, obtaining a refractive index deviation corresponding to predetermined target distribution information.

[0079] Specifically, the refractive index deviation is the difference between the preset ideal refractive index and the real refractive index. Since the real refractive index at each point of the immersion liquid is not exactly the same, the refractive index deviation at each point of the immersion liquid is also not exactly the same. However, the refractive index deviation of the immersion liquid obeys specific distribution information, namely the target distribution information. Among them, the preset ideal refractive index is the refractive index corresponding to the immersion liquid under the condition of uniform influencing factors, and the influencing factors include temperature, flow rate, etc.

[0080] Exemplarily, the target distribution information is determined by: acquiring a temperature fluctuation value of the immersion liquid; and determining the target distribution information corresponding to the temperature fluctuation value of the immersion liquid from a pre-constructed mapping relationship.

[0081] The pre-constructed mapping relationship is the relationship between "immersion liquid temperature fluctuation amplitude" and "refractive index deviation distribution information". The mapping relationship between temperature fluctuation amplitude and refractive index is provided by the immersion liquid manufacturer. After obtaining the temperature fluctuation amplitude of the immersion liquid, the refractive index deviation distribution information corresponding to the temperature fluctuation amplitude of the immersion liquid can be obtained from the mapping relationship. For example, when the temperature fluctuation amplitude is 1mK, the refractive index deviation obeys Δn~U(1.25e -7 ); when the temperature fluctuation amplitude is 10mK, the refractive index deviation obeys Δn~U(1e -6 ).

[0082] Step b2, adjusting the phase difference of the mask plane based on the refractive index deviation and the preset propagation distance, and adjusting the spatial frequency of the light beam based on the preset ideal refractive index and the preset propagation distance.

[0083] Exemplarily, the adjusted phase difference is determined as follows:

[0084] Δθ′=Δn(x,y,z)·z0

[0085] Among them, Δθ′ is the new phase difference, Δn(x, y, z) is the refractive index deviation, and z0 is the preset propagation distance.

[0086] For example, when the temperature fluctuation amplitude is 1mK and z0=24mm, the refractive index deviation obeys Δn~U(1.25e -7 ), based on the above method, we can get Δθ′~U(1.25e -7 2.4e 7 )=U(3). When the temperature fluctuation amplitude is 10mK, the refractive index deviation obeys Δn~U(1e -6 ), based on the above method, we can get Δθ′~U(1e -6 2.4e 7 )=U(24).

[0087] Exemplarily, the spatial frequency of the adjusted light beam is determined as follows:

[0088] k′=n0·k

[0089] Wherein, k′ is the spatial frequency of the adjusted light beam, n0 is the preset ideal refractive index, and k is the propagation distance.

[0090] Step b3, generating a second wave aberration function based on the adjusted phase difference and the adjusted spatial frequency of the light beam.

[0091] Specifically, the second wave aberration function, namely, e ik′Δθ′ .

[0092] Step S2033, using the second wave aberration function to simulate the disturbance of the unevenly distributed refractive index on the simulated image, to obtain a simulated image of the holographic mask.

[0093] Exemplarily, the adjusted second wave aberration function is e ik′Δθ′ , the second wave aberration function is used to simulate the disturbance of the unevenly distributed refractive index on the simulated image, and the implementation method of obtaining the simulated image of the holographic mask is as follows:

[0094]

[0095] Wherein, U(x, y, z0)″ is the holographic mask simulation image obtained by perturbing the simulated image using the second wave aberration function.

[0096] For example, in this embodiment, the above-mentioned method for acquiring the simulated image of the holographic mask is used to carry out experiments. In this experiment, the immersion liquid is pure water, the preset ideal refractive index corresponding to pure water is n0≈1.43661642, the wavelength of the light beam in pure water corresponds to λ=193.368nm, the wavelength of the light beam in air corresponds to λ′=λ / n0=133.4nm, and the propagation distance z0=24mm. Based on the above-mentioned laboratory data and the analysis of the immersion liquid flow field simulation, it is known that in the calculation domain, there are:

[0097] When the immersion liquid temperature fluctuation amplitude is 1mK, the refractive index deviation Δn(x,y,z)~U(1.25e -7 ), where U(1.25e -7 ) represents the refractive index deviation obeys -1.25e -7 To 1.25e -7 Based on the method in step b2, we can get Δθ′~U(1.25e -7 2.4e 7 )=U(3).

[0098] When the immersion liquid temperature fluctuation amplitude is 10mK, the refractive index deviation Δn(x,y,z)~U(1e -6 ), where U(1e -6 ) represents the refractive index deviation obeys -1e -6 To 1e -6 Based on the method in step b2, we can get the uniform distribution between Δθ′ and U(1e -6 2.4e 7 )=U(24).

[0099] Based on the above basic data, according to the method for obtaining the mask simulation image described in the embodiment of the present invention, the laser illumination system is subjected to wave aberration simulation to simulate the influence of the imaging quality caused by the uneven distribution of the refractive index of the immersion liquid, thereby obtaining the following: Figure 3 The holographic mask simulation image when the temperature fluctuation amplitude of the immersion liquid pure water is 1mK is shown as follows Figure 4 The holographic mask simulation image shown is when the temperature fluctuation amplitude of the immersion liquid pure water is 10mK.

[0100] exist Figure 3 In the figure, the "L130" below each image indicates that the width of the line in the image is 130nm. The "HYPER-OPTICS" in the image indicates the circuit diagram in the circuit layout. Figure 3 From the image corresponding to the word "L100" in the figure, it can be seen that the temperature fluctuation amplitude of the 1mk immersion liquid has little effect on the resolution of the 100nm line image. Figure 4It can be seen from the image corresponding to the word "L100" that the temperature fluctuation amplitude of the 10mk immersion liquid will almost make the 100nm line image disappear, so it may not meet the imaging requirements for the time being.

[0101] In this embodiment, a method for acquiring a mask simulation image is provided. The method is applied to an exposure operation of an immersion holographic mask in a chip manufacturing process, and can be specifically used in an exposure device. Figure 5 FIG. 4 is a flow chart of a method for obtaining a mask simulation image according to an embodiment of the present invention. Figure 5 As shown, the process includes the following steps:

[0102] Step S501, obtaining the ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and the preset propagation distance. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0103] Step S502, based on the ideal wavefront, spatial frequency and preset propagation distance, simulate the diffraction image corresponding to the light beam after propagating the preset propagation distance. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0104] Step S503: perturb the diffraction image using a predetermined perturbation method to obtain a holographic mask simulation image. Figure 1 Step S303 of the illustrated embodiment will not be described in detail here.

[0105] Step S504: judging the eligibility of the holographic mask simulation image based on the image clarity.

[0106] For example, a clarity evaluation algorithm may be used to calculate the clarity corresponding to the holographic mask simulation image, and an image with a clarity higher than a preset clarity threshold may be determined as a qualified image.

[0107] In this embodiment, a device for acquiring a mask simulation image is also provided, and the device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are not repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0108] This embodiment provides a mask simulation image acquisition device, which is applied to the immersion holographic exposure operation of the chip manufacturing process, such as Figure 6 As shown, it includes a data acquisition module 601, an image simulation module 602 and an image acquisition module 603.

[0109] The data acquisition module 601 is used to acquire the ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam and the preset propagation distance.

[0110] The image simulation module 602 is used to simulate the diffraction image corresponding to the light beam after propagating a preset propagation distance based on the ideal wavefront, the spatial frequency and the preset propagation distance.

[0111] The image acquisition module 603 is used to perturb the diffraction image using a predetermined perturbation method to acquire a holographic mask simulation image.

[0112] In some optional implementations, the image acquisition module 603 includes a first perturbation submodule, an adjustment submodule, and a second perturbation submodule.

[0113] The first perturbation submodule is used to simulate the perturbation of the diffraction image by the immersion liquid using a predetermined first wave aberration function to obtain a simulated image.

[0114] The adjustment submodule is used to adjust the first wave aberration function to the second wave aberration function.

[0115] The second perturbation submodule is used to simulate the perturbation of the simulated image by the unevenly distributed refractive index using the second wave aberration function to obtain a simulated image of the holographic mask.

[0116] In some optional embodiments, the submodule in the first perturbation submodule for determining the first wave aberration function includes a first determining unit and a second determining unit.

[0117] The first determining unit is used to take the phase difference that obeys the preset distribution information as an independent variable, where the phase difference is the phase difference between the ideal wavefront and the actual wavefront of the mask plane.

[0118] The second determining unit is used to determine the first wave aberration function based on the phase difference and the spatial frequency.

[0119] In some optional implementations, the adjustment submodule includes an acquisition unit, an adjustment unit, and a generation unit.

[0120] The acquisition unit is used to acquire the refractive index deviation corresponding to the predetermined target distribution information.

[0121] The adjustment unit is used to adjust the phase difference of the mask plane based on the refractive index deviation and the preset propagation distance, and to adjust the spatial frequency of the light beam based on the preset ideal refractive index and the preset propagation distance.

[0122] The generating unit is used to generate a second wave aberration function based on the adjusted phase difference and the adjusted spatial frequency.

[0123] In some optional implementations, the unit in the acquisition unit for determining the target distribution information includes an acquisition subunit and a determination subunit.

[0124] The acquisition subunit is used to obtain the immersion liquid temperature fluctuation value.

[0125] The determination subunit is used to determine the target distribution information corresponding to the immersion liquid temperature fluctuation value from the pre-constructed mapping relationship.

[0126] In some optional implementations, the image simulation module 602 includes a simulation submodule.

[0127] Using Rayleigh-Sommerfeld diffraction theory, the diffraction pattern is simulated based on the ideal wavefront, spatial frequency and preset propagation distance.

[0128] In some optional implementations, after the image acquisition module 603, the method further includes a judgment module.

[0129] The judging module is used to judge the eligibility of the holographic mask simulation image based on the image clarity.

[0130] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0131] The mask simulation image acquisition device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0132] The embodiment of the present invention also provides an exposure device having the above Figure 6 The device for acquiring the mask simulation image is shown.

[0133] See also Figure 7 , Figure 7 is a schematic diagram of the structure of an exposure device provided by an optional embodiment of the present invention, the exposure device is applied to a chip preparation process, such as Figure 7As shown, the exposure device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the exposure device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple exposure devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 7 A processor 10 is taken as an example.

[0134] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0135] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0136] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the exposure device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the exposure device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0137] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0138] The exposure device further includes a communication interface 30 for the exposure device to communicate with other devices or a communication network.

[0139] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0140] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for obtaining a mask simulation image, characterized in that: The method is applied to the exposure operation of an immersion holographic mask in a chip manufacturing process, comprising: Obtaining an ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, the spatial frequency of the light beam, and a preset propagation distance; Based on the ideal wavefront, the spatial frequency and the preset propagation distance, simulating a diffraction image corresponding to the light beam after propagating the preset propagation distance; The diffraction image is disturbed by using a predetermined disturbance method to obtain a holographic mask simulation image.

2. The method according to claim 1, characterized in that: The method of perturbing the diffraction image by a predetermined perturbation method to obtain a holographic mask simulation image includes: Using a predetermined first-wave aberration function to simulate the disturbance of the diffraction image by the immersion liquid, to obtain a simulated image; adjusting the first wave aberration function to a second wave aberration function; The second wave aberration function is used to simulate the disturbance of the simulated image caused by the unevenly distributed refractive index to obtain the holographic mask simulated image.

3. The method according to claim 2, characterized in that The determination of the first wave aberration function includes: Taking a phase difference that complies with preset distribution information as an independent variable, the phase difference being a phase difference between the ideal wavefront and an actual wavefront on the mask plane; Based on the phase difference and the spatial frequency, the first wave aberration function is determined.

4. The method according to claim 3, characterized in that The step of adjusting the first wave aberration function to a second wave aberration function comprises: acquiring a refractive index deviation corresponding to predetermined target distribution information; adjusting the phase difference of the mask plane based on the refractive index deviation and the preset propagation distance, and adjusting the spatial frequency of the light beam based on a preset ideal refractive index and the preset propagation distance; The second wave aberration function is generated based on the adjusted phase difference and the adjusted spatial frequency of the light beam.

5. The method according to claim 4, characterized in that The method for determining the target distribution information includes: Obtain the immersion liquid temperature fluctuation value; Target distribution information corresponding to the immersion liquid temperature fluctuation value is determined from a pre-constructed mapping relationship.

6. The method according to claim 1, characterized in that The simulating, based on the ideal wavefront, the spatial frequency and the preset propagation distance, a corresponding diffraction image of the light beam after propagating the preset propagation distance comprises: The diffraction image is simulated based on the ideal wavefront, the spatial frequency and the preset propagation distance using Rayleigh-Sommerfeld diffraction theory.

7. The method according to any one of claims 1 to 4, characterized in that After the diffraction image is disturbed by using a predetermined disturbance mode to obtain a holographic mask simulation image, the method further includes: The eligibility of the holographic mask simulation image is judged based on the image clarity.

8. A device for acquiring a mask simulation image, characterized in that: The device is applied to the immersion holographic exposure operation of the chip preparation process, comprising: A data acquisition module, used to acquire an ideal wavefront corresponding to the light beam at the mask plane of the holographic mask, a spatial frequency of the light beam, and a preset propagation distance; An image simulation module, configured to simulate a diffraction image corresponding to the light beam after the light beam propagates the preset propagation distance based on the ideal wavefront, the spatial frequency and the preset propagation distance; The image acquisition module is used to disturb the diffraction image using a predetermined disturbance method to obtain a holographic mask simulation image.

9. An exposure device, applied to a chip preparation process, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for acquiring a mask simulation image according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for acquiring a mask simulation image according to any one of claims 1 to 7.

Images