A lighting system

Abstract

The application provides a lighting system, which comprises a light source, a coupling unit, a light-uniformizing unit and a relay unit, the light-uniformizing unit comprises a first light-uniformizing element and a second light-uniformizing element, the second light-uniformizing element is additionally arranged on the upper and lower sides of the first light-uniformizing element, the second light-uniformizing element makes full use of the light energy which is not used in the first image field without affecting the original exposure field size and illumination and without increasing the lighting light source, and separately provides uniform illumination energy for the alignment mark located outside the exposure field, so that the effective utilization rate of light energy is improved, and the second light-uniformizing element can be freely selected, so that the freedom of the illumination field selection is improved.

Description

Technical Field

[0001] This invention relates to the field of alignment lighting, and more specifically to a lighting system. Background Technology

[0002] In a photolithography machine, when coaxial alignment is required, alignment marks on a photomask are projected onto the substrate surface through a projection lens, and the imaged marks are used for alignment. This process requires providing the alignment marks on the photomask with light energy of the required wavelength and energy, typically an illumination source for the exposure area.

[0003] When the coaxial alignment mark is located outside the exposure field of view, providing an exposure field of view for the coaxial alignment mark requires expanding the illumination area to cover it. This results in the same total optical power being dispersed over a larger area of ​​the illumination field of view, reducing illuminance and affecting the performance of the lithography machine. When additional optical fibers are used to increase illuminance, the fibers guide light from outside the illumination area to above the mask, providing an illumination field of view for the alignment mark. However, the uniformity of the illumination field of view provided by this method is insufficient. Summary of the Invention

[0004] Therefore, in order to overcome the shortcomings of the prior art, this application provides an illumination system that, without reducing the light intensity of the exposure area, makes full use of the unused light energy in the first image field of view to provide a uniform illumination field for the alignment mark located outside the exposure field of view.

[0005] To achieve the above objectives, this application provides the following technical solution: an illumination system for providing an exposure field of view to a photomask, characterized in that it comprises:

[0006] A light source, used to provide a beam of light;

[0007] A coupling unit is used to modulate and transmit the light beam, and by changing the focal length of the coupling unit, different sizes of the first image-side field of view are provided;

[0008] A beam homogenizing unit is used to homogenize the beam in the first image field of view, and a beam of the same size as the exit end face is emitted from the exit end face of the beam homogenizing unit.

[0009] A relay unit is used to magnify the light beam emitted from the output end face of the uniform light unit by an equal ratio, and the exposure field of view and the illumination field of view are obtained after the equal ratio magnification.

[0010] The light-diffusing unit includes a first light-diffusing element and two second light-diffusing elements. Both the first and second light-diffusing elements are cuboids, and the two second light-diffusing elements are respectively disposed on the upper and lower sides of the first light-diffusing element. The incident end face of the first light-diffusing element is located in the first image-side field of view, and the exit end face of the first light-diffusing element is located in the second object-side field of view of the relay unit.

[0011] The light beam processed by the first homogenizing element is magnified proportionally to obtain the exposure field of view, and the light beam processed by the second homogenizing element is magnified proportionally to obtain the illumination field of view that covers the alignment mark not in the exposure field of view.

[0012] Specifically, the diagonal length of the incident end face of the first light-diffusing element is equal to the length of the first image-side field of view diameter.

[0013] Specifically, the length of the long side of the incident end face of the first light-diffusing element is the same as the length of the long side of the incident end face of the second light-diffusing element.

[0014] Specifically, the endpoints of the two second homogenizing elements that are far from the first homogenizing element overlap with the edge of the first image field of view.

[0015] Specifically, the connection methods between the first light-diffusing element and the second light-diffusing element include contact connection, optical adhesive bonding, and magnetic adsorption connection.

[0016] Specifically, the method of changing the focal length of the coupling unit includes adjusting the relative positions between the lenses in the coupling unit and replacing the lenses in the coupling unit.

[0017] Specifically, the second light-diffusing element is composed of multiple light-diffusing rods of relatively short length spliced ​​together.

[0018] Specifically, the incident end face and the exit end face of the second light-diffusing element are coated with films with different transmittance.

[0019] Specifically, the position of the incident end face of the at least one end of the second light-diffusing element is not the same as the position of the incident end face of the first light-diffusing unit, which is used to adjust the intensity of the incident light.

[0020] Specifically, the first light-diffusing element and the second light-diffusing element are made of light-guiding materials, including quartz or calcium fluoride.

[0021] Compared with the prior art, the advantages of this application are as follows: The illumination system of this application adds a second light-diffusing element on the upper and lower sides of the first light-diffusing element. Without affecting the original exposure field size and illuminance and without adding an illumination source, the second light-diffusing element makes full use of the unused light energy in the first image field and provides uniform illumination energy to the alignment mark located outside the exposure field, thereby improving the effective utilization rate of light energy. Furthermore, the second light-diffusing element can be freely selected, which improves the freedom of illumination field selection. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a lighting system according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram showing the positional relationship between the first image-side field of view and the incident end face of the first homogenizing element in an embodiment of this application;

[0025] Figure 3 This is a schematic diagram showing the relationship between the incident end face of the first light-diffusing element and the incident end face of the second light-diffusing element in an embodiment of this application.

[0026] Figure 4 This is a schematic diagram showing the relationship between the first image field of view, the incident end face of the first homogenizing element, and the incident end face of the second homogenizing element when the length of the long side of the exposure field of view is greater than the length of the long side of the illumination field of view in an embodiment of this application.

[0027] Figure 5 This is a schematic diagram showing the relationship between the first image field of view and the incident end face of the first homogenizing element and the second homogenizing element when the length of the long side of the exposure field of view is equal to the length of the long side of the illumination field of view in an embodiment of this application. Detailed Implementation

[0028] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0029] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] It should be noted that the following description covers various aspects of embodiments within the scope of protection of this invention. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0031] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0033] This application provides a lighting system, such as... Figure 1 As shown, it includes: a light source 101, a coupling unit 102, a light homogenizing unit 103, and a relay unit 104.

[0034] The light source 101, coupling unit 102, homogenizing unit 103 and relay unit 104 are located on the same straight line. The illumination system ultimately provides a rectangular exposure field of view 11 with a length of L1 and a width of W2, and an illumination field of view 12 covering the alignment mark located outside the exposure field of view 11.

[0035] The light source 101 can be a mercury lamp light source, a conventional bulb light source, an LED light source, or a laser light source, used to provide an illumination beam for the image coupling unit 102.

[0036] The coupling unit 102 is located on the propagation path of the illumination beam and is used to modulate and transmit the illumination beam provided by the light source 101, converting the illumination beam into an imaging beam. The imaging beam surface intersecting with the incident end face of the homogenizing unit 103 is a circular first image-side field of view 1021, that is, the cross-section of the imaging beam is a circular spot. The coupling unit 102 can change the size of the first image-side field of view 1021, i.e., the size of the circular spot, by adjusting its focal length.

[0037] The light-uniform unit 103 includes a first light-uniform element 1031 and two second light-uniform elements 1032, both of which are cuboids. The two second light-uniform elements 1032 are respectively disposed on the upper and lower sides of the first light-uniform element 1031. The first light-uniform element 1031 and the two second light-uniform elements 1032 are light-uniform integrating rods, specifically light-guiding materials such as quartz rods and calcium fluoride rods. A light-uniform integrating rod is an optical device used to control the propagation of light. Its working principle is to use refraction and total internal reflection to make light reflect and refract multiple times within the rod, achieving the effect of uniform light distribution.

[0038] The incident end face 1131 and the exit end face 1231 of the first homogenizing element 1031 are both rectangles with a length of L1 / M and a width of W1 / M. The incident end face 1131 of the first homogenizing element 1031 is located within the first image-side field of view 1021. A beam of light with a rectangular cross-section of length L1 / M and width W1 / M is emitted from the exit end face 1131 of the first homogenizing element 1031, that is, a beam of light providing a rectangular light spot with a length of L1 / M and width of W1 / M. The incident end face 1132 and the exit end face 1231 of the two second homogenizing elements 1032 are both rectangles with a length of L2 / M and a width of W2 / M. A beam of light with a rectangular cross-section of length L2 / M and width W2 / M is emitted from the exit end face 1132 of the two second homogenizing elements 1032, that is, a beam of light providing a rectangular light spot with a length of L2 / M and width of W2 / M.

[0039] The relay unit 104 provides a second object-side field of view 1041, and the exit end face 1231 of the first homogenizing element 1031 is located in the second object-side field of view 1041. The magnification of the relay unit 104 is M, which magnifies the light spot emitted from the exit end of the homogenizing unit 103 proportionally. Specifically, the relay unit 104 magnifies the light spot emitted from the exit end of the first homogenizing element 1031 by a factor of M to form the exposure field of view 11, and the relay unit 104 magnifies the light spots emitted from the exit ends of the two second homogenizing elements 1032 by a factor of M to form the illumination field of view 12.

[0040] The illumination field of view 12 covers the alignment mark located outside the exposure field of view 11. Providing light energy to the alignment mark without introducing other light sources maximizes the utilization of light energy, integrating resources and making the most of available resources.

[0041] The light source 101 emits a light beam, which enters the coupling unit 102. The coupling unit 102 modulates and transmits the light beam, and provides a circular first image-side field of view 1021 at the output end of the coupling unit 102. The diameter of the first image-side field of view 1021 provided by the coupling unit 102 is not less than (L1+M1). 0.5 / M. The diameter of the second object-side field of view 1041 of the relay unit 104 is not less than (L1+M1). 0.5 / M. The incident end face 1131 of the first homogenizing element 1031 is on the same plane as the first image-side field of view 1021, and the first homogenizing element 1031 is located within the circular first image-side field of view 1021. The incident end face 1131 and the exit end face 1231 of the first homogenizing element 1031 are both rectangles with a length of L1 / M and a width of W1 / M. The first homogenizing element 1031 homogenizes and transmits the light beam in the portion overlapping with the first image-side field of view 1021, providing a rectangular light spot with a length of L1 / M and a width of W1 / M at the exit end of the first homogenizing element 1031. The exit end face 1231 of the first homogenizing element 1031 is located within the second object-side field of view 1041 of the relay unit 104. The relay unit 104 magnifies the rectangular light spot with a length of L1 / M and a width of W1 / M provided by the emitting end of the first homogenizing element 1031 by a factor of M, providing a rectangular exposure field of view 11 with a length of L and a width of W on the mask. The incident end face 1132 and the emitting end face 1232 of the two second homogenizing elements 1032 are rectangles with a length of L2 / M and a width of W2 / M. The two second homogenizing elements 1032 are respectively disposed on the upper and lower sides of the first homogenizing element 1031. Utilizing part of the light energy outside the overlapping part of the circular first image-square field of view 1021 and the incident end face 1131 of the first homogenizing element 1031, the two second homogenizing elements 1032 individually perform homogenization and transmission processing on the light beam outside the overlapping part of the circular first image-square field of view 1021 and the incident end face 1131 of the first homogenizing element 1031. A rectangular light spot with a length of L² / M and a width of W² / M is provided at the emitting end of the two second homogenizing elements 1032. The relay unit 104 magnifies the rectangular light spot with a length of L² / M and a width of W² / M provided at the emitting end of the two second homogenizing elements 1032 by a factor of M, providing two rectangular illumination fields 12 with a length of L² and a width of W² located on the upper and lower sides of the exposure field of view 11 on the mask. The illumination fields 12 cover the alignment marks located outside the exposure field of view 11.

[0042] In the aforementioned illumination system, the first homogenizing element 1031 remains unchanged, satisfying the original size requirements of the exposure field of view 11, providing the mask with a rectangular exposure field of view 11 of length L1 and width W1, and the illuminance of the exposure field of view 11 remains unaffected and consistent with the original. Two second homogenizing elements 1032 are added to the upper and lower sides of the first homogenizing element 1031, eliminating the need for additional illumination sources. The two second homogenizing elements 1032 fully utilize the unused light energy of the first image-side field of view 1021, providing uniform illumination energy to the alignment marks located outside the exposure field of view 11, improving the effective utilization rate of light energy. Furthermore, the second homogenizing elements 1032 can be freely selected, increasing the freedom of choice in the illumination field of view 12.

[0043] In one embodiment, such as Figure 2 As shown, the diameter of the circular first image-side field of view 1021 is (L1+M1). 0.5 / M, at this time, the diagonal length of the incident end face 1131 of the first homogenizing element 1031 is equal to the diameter of the circular first image-square field of view 1021, that is, the four endpoints of the incident end face 1131 of the first homogenizing element 1031 coincide with the edge of the circular first image-square field of view 1021, and the circular first image-square field of view 1021 is the circumcircle of the incident end face 1131 of the first homogenizing element 1031. The first homogenizing element 1031 has the highest light energy utilization rate in the circular first image-square field of view 1021, and transmits light energy to the exposure field of view 11 to the maximum extent.

[0044] In one embodiment, such as Figure 3 As shown, the length L2 / M of the incident end face 1132 of the second homogenizing element 1032 is equal to L1 / M, meaning the length of the long side of the incident end face 1131 of the first homogenizing element 1031 is the same as the length of the long side of the incident end face 1132 of the second homogenizing element 1032. At this time, the second homogenizing element 1032 provides a rectangular light spot with a length of L2 / M and a width of W2 / M. After being magnified M times by the relay unit 104, the length of the long side of the rectangular illumination field of view 12 is L2, which is consistent with the length of the long side L1 of the rectangular exposure field of view 11. The alignment mark can be located anywhere on the upper and lower edges of the exposure field of view 11. The illumination field of view 12 has a large field of view, providing the maximum range of illumination.

[0045] In one embodiment, the four endpoints of the incident end faces 1132 of the two second homogenizing elements 1032 that are far from the first homogenizing element 1031 all overlap with the edge of the first image-side field of view 1021. The entire incident end faces 1132 of the two second homogenizing elements 1032 are located within the first image-side field of view 1021, maximizing the utilization of the two second homogenizing elements 1032. Figure 4 As shown, when the diameter of the first circular image field of view 1021 is (L1+W1) 2 ) 0.5When / M, the length of the long side of the rectangular incident end face 1132 of the two second light-diffusing elements 1032 is less than the length of the long side of the rectangular incident end face 1131 of the first light-diffusing element 1031. At this time, the first light-diffusing element 1031 has the highest light energy utilization rate. After final processing, it provides an exposure field of view 11 with a length of L1 and a width of W1 to the mask. Without adding an additional light source, the two added second light-diffusing elements 1032 can provide an illumination field of view 12 covering the alignment marks to the mask. Figure 5 As shown, when the length L2 / M of the incident end face 1132 of the second homogenizing element 1032 is equal to L1 / M, that is, when the length of the long side of the incident end face 1131 of the first homogenizing element 1031 is the same as the length of the long side of the incident end face 1132 of the second homogenizing element 1032, the diameter of the circular first image-side field of view 1021 is [L1+(W1+2×W2)]. 0.5 / M, the rectangular incident end face 1131 of the first homogenizing element 1031 and the rectangular incident end faces 1132 of the two second homogenizing elements 1032 are all located within the first image field of view 1021, providing a large-size illumination field of view 12 to the mask.

[0046] In one embodiment, the connection between the first light-diffusing element 1031 and the second light-diffusing element 1032 includes abutment connection, optical adhesive bonding, and magnetic adsorption connection.

[0047] In one embodiment, the focal length of the coupling unit 102 is changed by adjusting the relative positions between the lenses in the coupling unit 102 and by replacing the lenses in the coupling unit 102.

[0048] In one embodiment, the second light-diffusing element 1032 is composed of multiple shorter light-diffusing rods spliced ​​together, reducing the processing difficulty and cost of the longer second light-diffusing element 1032, and also reducing assembly difficulty during integration, avoiding uneven stress during assembly caused by excessively long cuboid second light-diffusing elements 1032, which could damage the second light-diffusing element 1032. Furthermore, the incident and exit surfaces of the light-diffusing unit 103 can be coated with the required spectral cutoff film layers according to the specific requirements of the illumination field of view 12, thereby modulating the light beam and ultimately obtaining the illumination field of view 12 according to specific needs.

[0049] In one embodiment, the incident end face 1132 and the exit end face 1232 of the second light-diffusing element 1032 are coated with films with different transmittance, which can discretely adjust the illuminance. The intensity of the illumination field of view 12 can be adjusted individually to match the alignment detector, increasing the system's degrees of freedom.

[0050] In one embodiment, the position of the incident end face 1132 of at least one end of the second light-diffusing element 1032 is inconsistent with the position of the incident end face 1131 of the first light-diffusing unit 1031, which is used to adjust the intensity of the incident light. According to the light intensity requirements of the illumination field of view 12, when the light intensity is too high, a film layer with a certain transmittance is deposited on the incident end face 1132 or the exit end face 1232 of the second light-diffusing element 1032 to reduce energy and thus reduce the light intensity of the illumination field of view; when the light intensity is low, the position of the incident end face 1132 of the second light-diffusing element 1032 is adjusted, and the incident end face 1132 of the second light-diffusing element 1032 is moved towards the coupling unit 102 side to increase the light intensity of the illumination field of view 12 within a certain range.

[0051] In one embodiment, the first light-diffusing element 1031 and the second light-diffusing element 1032 are made of light-guiding materials, including quartz and calcium fluoride.

[0052] Example 1

[0053] An illumination system provides a rectangular exposure field of view with length L1 and width W1, and rectangular illumination fields of length L2 and width W2 located on the upper and lower sides of the exposure field of view, wherein L1 = L2 and the magnification of the relay unit is M.

[0054] like Figure 5 As shown, the first image-side field of view 1021 is the circumcircle of the incident end face 1131 of the first homogenizing element 1031 and the incident end face 1132 of the second homogenizing element 1032; the second object-side field of view 1041 is the circumcircle of the exit end face 1232 of the first homogenizing element 1031 and the second homogenizing element 1032. The diameters of both the first image-side field of view 1021 and the second object-side field of view 1041 are [L1 + (W1 + 2 × W2)]. 0.5 / M.

[0055] The first light-diffusing element 1031 is a rectangular quartz rod, and the second light-diffusing element 1032 is a rectangular quartz rod. The incident end face 1131 and the exit end face 1231 of the first light-diffusing element 1031 are both rectangles with a length of L1 / M and a width of W1 / M. The incident end face 1132 and the exit end face 1232 of the second light-diffusing element 1032 are both rectangles with a length of L2 / M and a width of W2 / M. L1 = L2, meaning that the length L1 / M of the long side of the rectangular incident end face 1131 and the exit end face 1231 of the first light-diffusing element 1031 is the same as the length L2 / M of the long side of the rectangular incident end face 1132 and the exit end face 1232 of the second light-diffusing element 1032.

[0056] The four endpoints of the incident end face 1132 of the second homogenizing element 1032 that are far from the first homogenizing element 1031 overlap with the edge of the first image-side field of view 1021; the four endpoints of the exit end face 1232 of the second homogenizing element 1032 that are far from the first homogenizing element 1031 overlap with the edge of the second object-side field of view 1041.

[0057] The light source emits a light beam, which enters the coupling unit. The coupling unit modulates and transmits the light beam, and provides a diameter of [L1 + (W1 + 2 × W2)] at the output end of the coupling unit. 0.5 The first image-side field of view 1021 of / M, the incident end face 1131 of the first light-diffusing element 1031 and the incident end face 1132 of the second light-diffusing element 1032 are located within the first image-side field of view 1021. The long side length L1 / M of the rectangular incident end face 1131 and the exit end face 1231 of the first light-diffusing element 1031 is the same as the long side length L2 / M of the rectangular incident end face 1132 and the exit end face 1232 of the second light-diffusing element 1032. The first image-side field of view 1021 is the circumcircle of the large rectangle formed by the incident end face 1131 of the first light-diffusing element 1031 and the incident end face 1132 of the second light-diffusing element 1032. The first homogenizing element 1031 homogenizes the light beam entering from the incident end face 1131, and emits a rectangular light beam with a length of L1 / M and a width of W1 / M from the exit end face 1231 of the first homogenizing element 1031. The second homogenizing element 1032 homogenizes the light beam entering from the incident end face 1132, and emits a rectangular light beam with a length of L2 / M and a width of W2 / M from the exit end face 1232 of the second homogenizing element 1032. The incident end of the relay unit provides a diameter of [L1 + (W1 + 2 × W2)]. 0.5 The second object-side field of view 1041 is L1 / M. The exit end face 1231 of the first homogenizing element 1031 and the exit end face 1232 of the second homogenizing element 1032 are located within the second object-side field of view 1041, and the second object-side field of view 1041 is the circumcircle of the large rectangle formed by the exit end face 1231 of the first homogenizing element 1031 and the exit end face 1232 of the second homogenizing element 1032. The relay unit magnifies the beam of the rectangular light spot with length L1 / M and width W1 / M by a factor of M to obtain a rectangular exposure field of view with length L1 and width W1; the relay unit magnifies the beam of the rectangular light spot with length L2 / M and width W2 / M by a factor of M to obtain a rectangular illumination field of view with length L2 and width W2.

[0058] The resulting rectangular exposure field of view has the same long side length L1 as the rectangular illumination field of view L2, resulting in a large illumination field of view. The alignment mark can be located at any position above or below the exposure field of view. Even if the alignment mark is located at a corner, the illumination field of view can still cover the alignment mark, achieving a higher precision alignment effect.

[0059] Example 2

[0060] An illumination system provides a rectangular exposure field of view with length L1 and width W1, and rectangular illumination fields of length L2 and width W2 located on the upper and lower sides of the exposure field of view, wherein L1 > L2, and the magnification of the relay unit is M.

[0061] like Figure 4 As shown, the first image-side field of view 1021 is the circumcircle of the incident end face 1131 of the first homogenizing element 1031; the second object-side field of view 1041 is the circumcircle of the exit end face 1231 of the first homogenizing element 1031. The diameters of both the first image-side field of view 1021 and the second object-side field of view 1041 are (L1+W1). 0.5 / M.

[0062] The incident end face 1131 and the exit end face 1231 of the first light-diffusing element 1031 are both rectangles with a length of L1 / M and a width of W1 / M, and the incident end face 1132 and the exit end face 1232 of the second light-diffusing element 1032 are both rectangles with a length of L2 / M and a width of W2 / M.

[0063] The four endpoints of the two second homogenizing elements 1032, located on their incident end faces 1132 and far from the first homogenizing element 1031, overlap with the edge of the first image-side field of view 1021; the four endpoints of the second homogenizing elements 1032, located on their exit end faces 1232 and far from the first homogenizing element 1031, overlap with the edge of the second object-side field of view 1041. That is, [L2 + (W1 + 2 × W2)]. 2 ] 0.5 / M=(L1+W1) 0.5 / M.

[0064] The light source emits a light beam, which enters the coupling unit. The coupling unit modulates and transmits the light beam, and provides a diameter of (L1+W1) at the output end of the coupling unit. 0.5The first image-side field of view 1021 is located within the incident end face 1131 of the first homogenizing element 1031, and the first image-side field of view 1021 is the circumcircle of the incident end face 1131 of the first homogenizing element 1031. The first homogenizing element 1031 homogenizes the light beam entering from the incident end face 1131 and emits a rectangular light beam with a length of L1 / M and a width of W1 / M from the exit end face 1231 of the first homogenizing element 1031. The four endpoints of the two second homogenizing elements 1032, located away from the first homogenizing element 1031, on their incident end faces 1132, all overlap with the edge of the first image-side field of view 1021. The entire incident end faces 1132 of the two second homogenizing elements 1032 are located within the first image-side field of view 1021. The second homogenizing elements 1032 homogenize the light beam entering from the incident end faces 1132, and emit a rectangular light beam with a length of L² / M and a width of W² / M from the exit end faces 1232 of the second homogenizing elements 1032. The incident end of the relay unit provides a beam with a diameter of (L1+W1). 0.5 The second object-side field of view 1041 is L1 / M. The exit end face 1231 of the first homogenizing element 1031 and the exit end face 1232 of the second homogenizing element 1032 are located within the second object-side field of view 1041, and the second object-side field of view 1041 is the circumcircle of the exit end face 1231 of the first homogenizing element 1031. The relay unit magnifies the beam of a rectangular light spot with length L1 / M and width W1 / M by a factor of M to obtain a rectangular exposure field of view with length L1 and width W1; the relay unit magnifies the beam of a rectangular light spot with length L2 / M and width W2 / M by a factor of M to obtain a rectangular illumination field of view with length L2 and width W2.

[0065] Finally, a rectangular exposure field of view with length L1 and width W1 and a rectangular illumination field of view with length L2 and width W2 are obtained. In this embodiment, the first homogenizing element has the highest light energy utilization rate in the first image field of view. While ensuring the highest light energy utilization rate in the exposure field of view, the second homogenizing element makes the most of the light energy in the first image field of view that is not utilized by the first homogenizing element to provide an illumination field of view for the mask, thereby improving the effective utilization rate of light energy.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An illumination system for providing an exposure field of view to a reticle, characterized in that, The application relates to a light source for providing a light beam; a coupling unit for modulated transmission of the light beam, different sizes of a first image field of view being provided by changing the focal length of the coupling unit; a light homogenizing unit for light homogenizing treatment of the light beam in the first image field of view, the light beam being emitted from the exit end face of the light homogenizing unit as large as the exit end face; and a relay unit for equal-ratio amplification of the light beam emitted from the exit end face of the light homogenizing unit, the exposure field of view and the illumination field of view being obtained after equal-ratio amplification. The light homogenizing unit comprises a first light homogenizing element and two second light homogenizing elements, the first light homogenizing element and the second light homogenizing element are cuboids, and the two second light homogenizing elements are arranged on the upper and lower sides of the first light homogenizing element; the incident end face of the first light homogenizing element is located in the first image field of view, and the exit end face of the first light homogenizing element is located in the second object field of view of the relay unit; the light beam treated by the first light homogenizing element is equal-ratio amplified to obtain the exposure field of view, and the light beam treated by the second light homogenizing element is equal-ratio amplified to obtain the illumination field of view covering the alignment mark not in the exposure field of view. The diagonal length of the incident end face of the first light homogenizing element is equal to the circular diameter length of the first image field of view. The long side length of the incident end face of the first light homogenizing element is consistent with the long side length of the incident end face of the second light homogenizing element. The end points of the incident end faces of the two second light homogenizing elements away from the first light homogenizing element are overlapped with the edges of the first image field of view. The connection mode between the first light homogenizing element and the second light homogenizing element comprises abutting connection, optical glue bonding and magnetic adsorption connection. The changing mode of the focal length of the coupling unit comprises adjusting the relative positions of the lenses in the coupling unit and replacing the lenses in the coupling unit.

2. A lighting system according to claim 1, characterized in that The second light homogenizing element is spliced by a plurality of light homogenizing rods with relatively short lengths.

3. A lighting system according to claim 1, characterized in that The incident end face and the exit end face of the second light homogenizing element are coated with film layers with different transmittances.

4. A lighting system according to any of claims 1 to 3, characterized in that The incident end face positions of at least one second light homogenizing element are inconsistent with the incident end face position of the first light homogenizing element, and are used for adjusting the intensity of incident light.

5. A lighting system according to claim 1, characterized in that The materials of the first light homogenizing element and the second light homogenizing element are light-guiding materials, including quartz or calcium fluoride.

6. A lighting system according to claim 1, characterized in that ​ 7. A lighting system according to claim 1, characterized in that ​ 8. A lighting system according to claim 1, characterized in that ​ 9. A lighting system according to claim 1, characterized in that ​ 10. A lighting system according to claim 1, characterized in that ​

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