Grazing incidence variable magnification extreme ultraviolet lithography illumination system and design method

Abstract

The invention provides a grazing incidence variable magnification extreme ultraviolet lithography illumination system and a design method, a relay lens group of the illumination system adopts a system structure combining normal incidence and grazing incidence and adopts a two-reflection structure, the light incidence form of one reflection mirror is grazing incidence, and the light incidence form of the other reflection mirror is normal incidence. Compared with an existing relay lens group design, a two-reflector structure is also adopted, but the light incidence form of the two reflectors is normal incidence, and the light incidence form is grazing incidence, so that the reflectivity is improved; in order to realize different illumination modes, the invention provides a multi-optimization parameter double-row compound eye matching method. According to the method, a plurality of parameters influencing illumination uniformity are determined, the parameters are used for calculating a cost value and establishing a cost matrix, a Kuhn-Munkres algorithm is used for calculation to obtain the optimal matching relation of double rows of compound eyes, and compared with an existing double-row compound eye matching model, only one parameter influencing illumination uniformity is considered, the illumination uniformity is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical design, and in particular relates to a grazing-incidence variable-magnification extreme ultraviolet lithography illumination system and a design method. Background Art

[0002] Extreme ultraviolet (EUV) lithography is a technology that uses an extreme ultraviolet light source with a wavelength of 13.5nm to shrink the integrated circuit structure on the mask and transfer it to the wafer through the exposure system of the lithography machine.

[0003] To meet the manufacturing needs of advanced technology nodes, the numerical aperture (NA) of the EUV lithography objective system has been increasing from 0.33, 0.55 to 0.75. In order to avoid the overlap of the incident light cone and the reflected light cone and the mask shadow effect caused by the large incident angle of the main light, the latest EUV lithography objective system adopts a variable magnification design, that is, the magnification in the scanning direction is increased from 4× to 8×, and the magnification in the vertical scanning direction remains at 4×. The variable magnification EUV lithography objective system with different magnifications in the scanning direction and the vertical scanning direction will produce an elliptical entrance pupil, so the exit pupil of the EUV lithography illumination system must match the elliptical entrance pupil of the variable magnification EUV lithography objective system.

[0004] The main function of the EUV lithography illumination system is to provide highly uniform illumination for the mask surface and realize multiple illumination modes. The EUV lithography illumination system consists of a double row of compound eyes and a relay mirror group. The double row of compound eyes consists of a field compound eye and an aperture compound eye, which can adjust the illumination mode of the EUV lithography illumination system by converting the matching relationship between the field compound eye and the aperture compound eye; the relay mirror group can realize two optical conjugate relationships in Kohler illumination, namely the conjugation between the mask surface and the field compound eye and the conjugation between the exit pupil surface and the aperture compound eye.

[0005] The light incident form of the reflector of the relay mirror group of the existing EUV lithography illumination system is normal incidence, and the reflectivity is low. In addition, the double-row compound eye matching method of the existing EUV lithography illumination system only considers one factor that affects the illumination uniformity, and uses this as an optimization index to determine the matching relationship between each field of view compound eye element and each aperture compound eye element, ignoring other factors that affect the illumination uniformity, and the illumination uniformity is difficult to meet the optimal design index. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a grazing-incidence variable-magnification extreme ultraviolet lithography illumination system and design method, which can achieve high reflectivity and high illumination uniformity in a variety of illumination modes.

[0007] A variable magnification extreme ultraviolet lithography illumination system adopts a grazing incidence relay mirror group, including a first relay mirror and a second relay mirror;

[0008] The light emitted by the light source passes through the field compound eye and the aperture compound eye in turn, is reflected by the second relay mirror and enters the first relay mirror, and then enters the mask surface after being reflected by it; among them, the light incident on the second relay mirror is in the form of grazing incidence, and the light incident on the first relay mirror is in the form of normal incidence.

[0009] Preferably, the first relay mirror is a plane reflector; and the second relay mirror is a quadratic curved reflector.

[0010] A design method for a variable magnification extreme ultraviolet lithography illumination system, comprising:

[0011] In the paraxial approximation, the transmission and refraction of light in the optical system are described in matrix form:

[0012]

[0013] Where y and y′ are the object-side paraxial ray height and image-side paraxial ray height, respectively; n and n′ are the object-side refractive index and image-side refractive index, respectively; u and u′ are the object-side paraxial ray angle and image-side paraxial ray angle, respectively; d is the distance between the two surfaces in the system; r is the radius of the optical element;

[0014] The transmission matrix T and the refraction matrix R are defined as:

[0015]

[0016] Under the definition of the transmission matrix T and the refraction matrix R, the matrix of a system with k faces is represented as the product of multiple matrices:

[0017]

[0018] Among them, R k represents the refraction matrix of the kth surface; T k-1 represents the transmission matrix of the k-1th surface; y 1 、n 1 and u 1 The first side Object paraxial ray height, object refractive index, object paraxial ray angle;

[0019] The matrix S is the transmission matrix of light through the optical system, which describes the influence of the elements in the optical system on a certain beam of light and is defined as:

[0020]

[0021] In the formula, the matrix elements A, B, C, and D are Gaussian constants. According to the properties of matrices, the determinant of the product of multiple matrices is equal to the product of the determinants of multiple matrices. The Gaussian constants in the matrix S satisfy the following formula:

[0022] AD-BC=1 (7)

[0023] The matrix M describing the light transmission between a pair of conjugate surfaces is defined as:

[0024]

[0025] Where, d o With d i are the object distance and the image distance respectively; β and α are the vertical axis magnification and axial magnification between the pair of conjugate planes respectively;

[0026] Use l p With l p ' represents the distance from the relay lens 1 to the exit pupil and the aperture compound eye respectively; l m and l′ m Represents the distance from relay lens 1 to the mask and the intermediate image point respectively; l pm Indicates the distance from the mask to the exit pupil, l pm represents the distance from the intermediate image point to the compound eye of the aperture; the relationship between these parameters is expressed by the following formula:

[0027]

[0028] In the above formula, r relay1 is the radius of the first relay mirror surface;

[0029] The light propagation matrix of the relay mirror group is:

[0030]

[0031] The light propagation matrix between the exit pupil and the aperture compound eye is:

[0032]

[0033] The light propagation matrix between the mask and its intermediate image plane is:

[0034]

[0035] According to formula (8), the following formula is obtained:

[0036]

[0037] In the formula, β p With β m are the vertical axis magnification of the exit pupil and the vertical axis magnification of the mask respectively;

[0038] Substituting equation (9) into equation (12) and combining equation (7), Gaussian constants A, B, C, and D are expressed as:

[0039]

[0040] According to formula (10), the radius r of the first relay mirror in the relay mirror group is relay1 It can be expressed as:

[0041] r relay1 =-2 / C. (15)

[0042] r relay1 From the parameter β in equation (14) and equation (15), p , β m With l pm Calculation; According to formula (14) and formula (15), when the parameter β p ,β m , and l pm After determination, the initial coaxial spherical structures of multiple groups of grazing-incidence relay mirrors are obtained, from which the initial structures that meet the requirements are determined to complete the design.

[0043] A matching method between a field compound eye element and an aperture compound eye element in a variable magnification extreme ultraviolet lithography illumination system is proposed. When an illumination channel is composed of the i-th field compound eye element and the j-th aperture compound eye element, the cost value of the illumination channel is:

[0044] MF ij ={w mask_θ |θ ij |+w mask_x |X ij |+w mask_y |Y ij |} (16)

[0045] In the formula, θ ij is the tilt angle of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element on the mask surface, w mask_θ is the weight of the tilt angle of the light spot generated on the mask surface; X ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the x direction of the mask surface, w mask_x Y is the weight of the offset of the light spot generated in the x direction of the mask surface; ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the y direction of the mask surface, w mask_y is the weight of the offset of the light spot generated in the y direction of the mask surface;

[0046] θ ij , X ij With Y ij All of them can be obtained by ray tracing. Under the illumination channel composed of the i-th field compound eye element and the j-th aperture compound eye element, two rays are traced from the intermediate image plane to the middle points on both sides of the field compound eye element, and the coordinates of the intersection of these two rays with the mask surface are obtained as (x1 ,y 1 ) and (x 2 ,y 2 );The tilt angle of the light spot on the mask surface is θ ij Calculated by the following formula:

[0047]

[0048] The offset X of the light spot in the x direction of the mask surface ij Calculated by the following formula:

[0049]

[0050] The offset Y of the light spot in the y direction of the mask surface ij Calculated by the following formula:

[0051]

[0052] In a specific lighting mode, the tilt angle and offset of the light spot under different matching relationships are used as the cost value MF in the allocation problem. ij , and form a cost matrix under different matching relationships; by using the Kuhn-Munkres algorithm, the optimal matching between the field of view compound eye element and the aperture compound eye element is obtained.

[0053] The present invention has the following beneficial effects:

[0054] The present invention proposes a grazing incidence variable magnification extreme ultraviolet lithography illumination system and design method. The relay mirror group of the illumination system adopts a system structure of a combination of normal incidence and grazing incidence, and adopts a two-reflection structure, in which the light incident form of one reflector is grazing incidence, and the light incident form of the other reflector is normal incidence. Compared with the existing relay mirror group design, which also adopts a two-reflection structure, but the light incident forms of the two reflectors are both normal incidence, and the light incident form is grazing incidence, the reflectivity is improved;

[0055] In order to realize different lighting modes, a multi-optimization parameter double-row compound eye matching method is proposed. Multiple parameters that affect the lighting uniformity are determined, and the cost values ​​are calculated using these parameters to establish a cost matrix. The optimal matching relationship of the double-row compound eyes is calculated using the Kuhn-Munkres algorithm. Compared with the existing double-row compound eye matching model that only considers one parameter that affects the lighting uniformity, the lighting uniformity is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the initial structure of the grazing incidence relay mirror assembly;

[0057] Figure 2 It is a quadratic off-axis relay mirror assembly;

[0058] Figure 3 Simplifying systems for extreme ultraviolet lithography illumination;

[0059] Figure 4 The light spot on the mask surface is formed by the optical path composed of the central field compound eye element and each aperture compound eye element;

[0060] Figure 5 is the cost matrix under different matching relationships;

[0061] Figure 6 It is a NA 0.55 grazing incidence variable magnification extreme ultraviolet lithography illumination system;

[0062] Figure 7 It is the field compound eye arrangement and the aperture compound eye arrangement;

[0063] Figure 8 Arrangement of the aperture compound eyes under different illumination modes. DETAILED DESCRIPTION

[0064] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0065] In the present invention, the grazing incidence relay mirror group obtains an initial structure through matrix optical calculation, and tilts and eccentrics the reflector in the initial structure, and finally fits the surface shape of the reflector into a quadratic surface.

[0066] Matrix optics is a method to describe optical systems under the paraxial approximation. This method describes the optical system in two situations, namely the transmission and refraction of light, which are described in matrix form as follows:

[0067]

[0068] Where y and y′ are the object-side paraxial ray height and image-side paraxial ray height, respectively; n and n′ are the object-side refractive index and image-side refractive index, respectively; u and u′ are the object-side paraxial ray angle and image-side paraxial ray angle, respectively; d is the distance between the two surfaces in the system; and r is the radius of the optical element.

[0069] The transmission matrix T and the refraction matrix R are defined as:

[0070]

[0071]

[0072] Under the definition of the transmission matrix T and the refraction matrix R, the matrix of a system with k faces can be expressed as the product of multiple matrices:

[0073]

[0074] The matrix S is the transmission matrix of light through the optical system, which describes the influence of the elements in the optical system on a certain beam of light and is defined as:

[0075]

[0076] In the formula, the matrix elements A, B, C, and D are Gaussian constants. According to the properties of matrices, the determinant of the product of multiple matrices is equal to the product of the determinants of multiple matrices. Therefore, the Gaussian constants in the matrix S satisfy the following formula:

[0077] AD-BC=1 (7)

[0078] The matrix M describing the light transmission between a pair of conjugate surfaces is defined as:

[0079]

[0080] Where, d o With d i are the object distance and the image distance respectively; β and α are the vertical magnification and axial magnification between the pair of conjugate planes respectively.

[0081] The initial structure of the grazing incidence relay mirror assembly is as follows: Figure 1 As shown. The relay lens group is a two-mirror system and has two optical conjugate relationships: the exit pupil is conjugate with the aperture compound eye, and the mask is conjugate with its own intermediate image point. p With l p ' represents the distance from the relay lens 1 to the exit pupil and the aperture compound eye respectively; l m and l′ m Represents the distance from relay lens 1 to the mask and the intermediate image point respectively; l pm Indicates the distance from the mask to the exit pupil, l pm Represents the distance from the intermediate image point to the aperture compound eye. The relationship between these parameters can be expressed by the following formula:

[0082]

[0083] r relay1 is the radius of the surface of the relay mirror 1. Among the parameters mentioned above, l p With r relay1 is an independent parameter of the relay mirror group, l p Determine the position of the reflector in the relay mirror assembly, r relay1 The position of the aperture compound eye and the intermediate image plane is determined. pm Determined by the objective system.

[0084] The light propagation matrix of the relay mirror set is

[0085]

[0086] The light propagation matrix between the exit pupil and the aperture compound eye is

[0087]

[0088] The light propagation matrix between the mask and its intermediate image plane is

[0089]

[0090] According to formula (8), the following formula can be obtained:

[0091]

[0092] In the formula, β p With β m They are the vertical magnification of the exit pupil and the vertical magnification of the mask respectively.

[0093] Substituting equation (9) into equation (12) and combining equation (7), the Gaussian constants A, B, C, and D can be expressed as

[0094]

[0095] According to formula (10), the radius r of the reflector in the relay mirror assembly is relay1 It can be expressed as

[0096] r relay1 =-2 / C. (15)

[0097] r relay1 From the parameter β in equation (14) and equation (15), p ,β m , and l pm Calculate, β p ,β m , and l pm are independent parameters of the relay mirror group, which represent the optical characteristics of the system. Therefore, according to equations (14) and (15), when the parameter β p ,β m , and l pm After determination, the initial coaxial spherical structures of many grazing incidence relay mirror groups can be obtained.

[0098] In order to eliminate light obstruction, the coaxial spherical initial structure of the grazing incidence relay mirror group must be tilted and eccentric. In the off-axis spherical initial structure, the surface of the relay mirror 1 will be fitted into a quadratic surface, such as Figure 2 As shown in Figure 2, the structure of the aperture compound eye can be determined by the conjugation between the exit pupil and the aperture compound eye. Similarly, the structure of the field compound eye can be determined by the conjugation between the mask and the field compound eye.

[0099] The double-row compound eye pairing method is a key technology to achieve different illumination modes in the EUV lithography illumination system. Different illumination modes can be achieved by adjusting the correspondence between each field compound eye element and the aperture compound eye element. In a specific illumination mode, by tilting the field compound eye element and the aperture compound eye element, the light spot of each illumination channel is superimposed on the mask surface, thereby achieving uniform illumination of the mask surface. A simplified diagram of the EUV lithography illumination system is shown in Figure 1. Figure 3 shown.

[0100] By tracing the light rays, we can obtain the light spot formed on the mask plane by the light path composed of the central field compound eye element and the different aperture compound eye elements, such as Figure 4 As shown. The light spot formed by the light passing through the central aperture compound eye is not tilted and has no offset in the x and y directions. However, the light spot formed by the edge aperture compound eye in the x direction is not only tilted, but also offset in the x and y directions. The light spot formed by the edge aperture compound eye in the y direction is offset in the x and y directions. In summary, the tilt of the light spot, the offset in the x direction, and the offset in the y direction will all lead to a decrease in illumination uniformity. Therefore, a double-row compound eye matching method is required to minimize the sum of the tilt angles and offsets of different light spots on the mask surface. This type of problem belongs to the allocation problem in combinatorial optimization, and is usually solved by the Kuhn-Munkres algorithm.

[0101] To solve this problem, the optimal values ​​of different allocation strategies are determined based on the tilt angle and offset of the light spot. When an illumination channel consists of the i-th field compound eye element and the j-th aperture compound eye element, the cost value of the illumination channel is:

[0102] MF ij ={w mask_θ |θ ij |+w mask_x |X ij |+w mask_y |Y ij |} (16)

[0103] In the formula, θ ij is the tilt angle of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element on the mask surface, w mask_θ is the weight of the tilt angle of the light spot generated on the mask surface; X ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the x direction of the mask surface, w mask_x Y is the weight of the offset of the light spot generated in the x direction of the mask surface; ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the y direction of the mask surface, w mask_y The weight of the offset of the light spot generated in the y direction of the mask plane.

[0104] θ ij , X ij With Y ij All of them can be obtained by ray tracing. Under the illumination channel composed of the i-th field compound eye element and the j-th aperture compound eye element, two rays are traced from the intermediate image plane to the middle points on both sides of the field compound eye element, and the coordinates of the intersection of these two rays with the mask surface are obtained as (x 1 ,y 1 ) and (x 2 ,y 2 ). The tilt angle θ of the light spot on the mask surface ij It can be calculated by the following formula:

[0105]

[0106] The offset X of the light spot in the x direction of the mask surface ij It can be calculated by the following formula:

[0107]

[0108] The offset Y of the light spot in the y direction of the mask surface ij It can be calculated by the following formula:

[0109]

[0110] In a specific lighting mode, the tilt angle and offset of the light spot under different matching relationships are used as the cost value MF in the allocation problem. ij , and form a cost matrix under different matching relationships, such as Figure 5 As shown in Figure 2, the optimal match of the double row of compound eyes is obtained by using the Kuhn-Munkres algorithm.

[0111] Based on the above design scheme, this embodiment has designed a set of illumination system matching NA 0.55 combined variable magnification extreme ultraviolet lithography objective lens, the structure of which is as follows: Figure 6As shown. The illumination system is a total reflection optical system, including a light source, a collecting mirror, a double row of compound eyes (field compound eyes and aperture compound eyes) and a relay mirror group (relay mirror 1, relay mirror 2). The specific working process is as follows: the light emitted by the LPP light source is collected by the ellipsoidal collecting mirror, converged on the intermediate image plane and incident on the double row of compound eyes. The wide light beam from the light source is divided into multiple fine light beams by the double row of compound eyes, and each fine light beam propagates in the corresponding optical channel. The fine light beam passes through the field compound eye in any optical channel and is imaged near the corresponding aperture compound eye to form an intermediate image of the light source, that is, the "secondary light source". The intermediate image is imaged on the exit pupil surface of the illumination system through the relay mirror group. At the same time, the field compound eye element itself is imaged on the illuminated surface through the corresponding aperture compound eye element and the relay mirror group, thereby forming a light spot with high illumination uniformity on the mask surface. Relay mirror 1 in the illumination system is an ellipsoidal reflector, relay mirror 2 is a plane reflector, and the parameters of the relay mirror group are shown in Table 1. The field of view compound eye element arrangement of the illumination system and the aperture compound eye element arrangement are as follows: Figure 7 The double-row compound eye matching of the illumination system adopts an automatic method to solve the arrangement of the aperture compound eye elements involved in the illumination for four illumination modes (ring illumination, diode illumination, quadrupole illumination and leaf illumination). The arrangement is shown in Figure 8 As shown. The field of view compound eye arrangement and the basic structure of the illumination system under various off-axis illumination modes are modeled in the optical design software and simulated by Monte Carlo ray tracing. The illumination uniformity of the illumination system is evaluated based on the simulation results. The illumination uniformity is calculated using the following formula:

[0112]

[0113] In the formula, I max with I min Respectively represent the irradiance distribution of the maximum and minimum light intensity line integrals in the scanning direction.

[0114] In summary, the grazing incidence variable magnification extreme ultraviolet lithography illumination system of this example can achieve uniform light through double-row compound eyes, and realize multiple off-axis illumination modes by adjusting the matching relationship of the double-row compound eyes. By matching the pupil of the subsequent objective lens system, a light spot with the same shape and size as the field of view of the subsequent objective lens system and high illumination uniformity is formed on the mask surface. The system meets the requirements of lithography technology and can be applied to lithography processes at higher technology nodes.

[0115] Table 1. Relay mirror set parameters

[0116]

[0117] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable magnification extreme ultraviolet lithography illumination system, characterized in that: A grazing incidence relay mirror group is adopted, including a first relay mirror and a second relay mirror; The light emitted by the light source passes through the field compound eye and the aperture compound eye in turn, is reflected by the second relay mirror and enters the first relay mirror, and then enters the mask surface after being reflected by it; among them, the light incident on the second relay mirror is in the form of grazing incidence, and the light incident on the first relay mirror is in the form of normal incidence.

2. The variable magnification extreme ultraviolet lithography illumination system according to claim 1, characterized in that: The first relay mirror is a plane reflector; the second relay mirror is a quadratic curved reflector.

3. A design method for a variable magnification extreme ultraviolet lithography illumination system according to claim 1, characterized in that: include: In the paraxial approximation, the transmission and refraction of light in the optical system are described in matrix form: Where y and y′ are the object-side paraxial ray height and image-side paraxial ray height, respectively; n and n′ are the object-side refractive index and image-side refractive index, respectively; u and u′ are the object-side paraxial ray angle and image-side paraxial ray angle, respectively; d is the distance between the two surfaces in the system; r is the radius of the optical element; The transmission matrix T and the refraction matrix R are defined as: Under the definition of the transmission matrix T and the refraction matrix R, the matrix of a system with k faces is represented as the product of multiple matrices: Among them, R k represents the refraction matrix of the kth surface; T k-1 represents the transmission matrix of the k-1th surface; y1, n1 and u1 are the first surface Object paraxial ray height, object refractive index, object paraxial ray angle; The matrix S is the transmission matrix of light through the optical system, which describes the influence of the elements in the optical system on a certain beam of light and is defined as: In the formula, the matrix elements A, B, C, and D are Gaussian constants. According to the properties of matrices, the determinant of the product of multiple matrices is equal to the product of the determinants of multiple matrices. The Gaussian constants in the matrix S satisfy the following formula: AD-BC=1 (7) The matrix M describing the light transmission between a pair of conjugate surfaces is defined as: Where, d o With d i are the object distance and the image distance respectively; β and α are the vertical axis magnification and axial magnification between the pair of conjugate planes respectively; Use l p With l p ' represents the distance from the relay lens 1 to the exit pupil and the aperture compound eye respectively; l m and l′ m Represents the distance from relay lens 1 to the mask and the intermediate image point respectively; l pm Indicates the distance from the mask to the exit pupil, l pm represents the distance from the intermediate image point to the compound eye of the aperture; the relationship between these parameters is expressed by the following formula: In the above formula, r relay1 is the radius of the first relay mirror surface; The light propagation matrix of the relay mirror group is: The light propagation matrix between the exit pupil and the aperture compound eye is: The light propagation matrix between the mask and its intermediate image plane is: According to formula (8), the following formula is obtained: In the formula, β p With β m are the vertical axis magnification of the exit pupil and the vertical axis magnification of the mask respectively; Substituting equation (9) into equation (12) and combining equation (7), Gaussian constants A, B, C, and D are expressed as: According to formula (10), the radius r of the first relay mirror in the relay mirror group is relay1 It can be expressed as: r relay1 ＝-2 / C. (15) r relay1 From the parameter β in equation (14) and equation (15), p , β m With l pm Calculation; According to formula (14) and formula (15), when the parameter β p ,β m , and l pm After determination, the initial coaxial spherical structures of multiple groups of grazing-incidence relay mirrors are obtained, from which the initial structures that meet the requirements are determined to complete the design.

4. A method for matching the field compound eye element and the aperture compound eye element in the variable magnification extreme ultraviolet lithography illumination system according to claim 1, characterized in that: When an illumination channel consists of the i-th field compound eye element and the j-th aperture compound eye element, the cost value of the illumination channel is: MF ij ={w mask_θ |θ ij |+w mask_x |X ij |+w mask_y |Y ij |} (16) In the formula, θ ij is the tilt angle of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element on the mask surface, w mask_θ is the weight of the tilt angle of the light spot generated on the mask surface; X ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the x direction of the mask surface, w mask_x Y is the weight of the offset of the light spot generated in the x direction of the mask surface; ij is the offset of the light spot generated by the i-th field compound eye element and the j-th aperture compound eye element in the y direction of the mask surface, w mask_y is the weight of the offset of the light spot generated in the y direction of the mask surface; θ ij , X ij With Y ij All can be obtained through ray tracing. Under the illumination channel composed of the i-th field compound eye element and the j-th aperture compound eye element, two rays are traced from the intermediate image plane to the middle points on both sides of the field compound eye element, and the coordinates of the intersection of these two rays with the mask surface are obtained as (x1, y1) and (x2, y2) respectively; the tilt angle θ of the light spot on the mask surface ij Calculated by the following formula: The offset X of the light spot in the x direction of the mask surface ij Calculated by the following formula: The offset Y of the light spot in the y direction of the mask surface ij Calculated by the following formula: In a specific lighting mode, the tilt angle and offset of the light spot under different matching relationships are used as the cost value MF in the allocation problem. ij , and form a cost matrix under different matching relationships; by using the Kuhn-Munkres algorithm, the optimal matching between the field of view compound eye element and the aperture compound eye element is obtained.

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