An objective lens performance detection device and an objective lens performance detection method
The objective lens performance testing device, which uses a multi-channel alignment sensor and a detection mark array, solves the problem that the accuracy of lithography machine projection lens testing depends on workpiece stage displacement and environmental fluctuations, and achieves efficient and accurate objective lens performance testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 智慧星空(上海)工程技术有限公司
- Filing Date
- 2024-12-30
- Publication Date
- 2026-06-23
Smart Images
Figure CN121048879B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of objective lens testing technology, specifically to an objective lens performance testing device and method. Background Technology
[0002] The performance of the projection lens has a significant impact on the operation of the lithography machine, therefore, it is necessary to test the performance of the projection lens. In existing technologies, a single-channel alignment sensor is used to test the performance of the projection lens, enabling the detection of properties such as distortion, magnification, and field curvature. However, the accuracy of this testing depends on the displacement accuracy of the stage; that is, errors caused by stage displacement will affect the accuracy of the lens performance testing.
[0003] In addition, since single-channel sensors detect at a single point, there is a time difference between different field points. Furthermore, during the test, environmental fluctuations and other changing factors can cause the position of the marker image formed by the objective lens on the detection mark set on the mask to drift as a whole, resulting in test errors for objective lens distortion, magnification, field curvature, etc. Summary of the Invention
[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to improve the accuracy and reliability of objective lens performance testing.
[0005] To address at least one of the aforementioned technical problems, this invention discloses an objective lens performance testing device and an objective lens performance testing method.
[0006] According to one aspect of this disclosure, an objective lens performance testing device is provided, having a first direction, a second direction, and a third direction that are mutually perpendicular to each other, the objective lens performance testing device comprising:
[0007] An illumination device, a first stage, an objective lens, and a second stage are arranged sequentially at intervals along the third direction. An alignment sensor is provided on the side of the second stage facing the objective lens, and the alignment sensor has at least two alignment detection channels.
[0008] The first platform is provided with a calibration mask on the side near the lighting device, and the calibration mask is provided with a first detection mark array;
[0009] When the illumination device is turned on, the image side of the objective lens forms a first marker image array corresponding to the first detection marker array, and the interval between two adjacent first marker images in the first marker image array is equal to the interval between two adjacent alignment detection channels.
[0010] The second stage can drive the alignment sensor to move, thereby determining the position deviation of the corresponding first marker image relative to the zero position of each alignment detection channel through each alignment detection channel, and realizing the aberration detection of the objective lens.
[0011] In some possible embodiments, when the illumination device is turned on, the objective lens forms an objective lens exposure field of view and a coaxial alignment field of view on its image side;
[0012] A portion of the first marker images in the first marker image array covers the objective lens exposure field of view, and another portion of the first marker images covers the coaxial alignment field of view;
[0013] In the coaxial alignment field of view, the number of the first detection markers is at least two.
[0014] In some possible embodiments, the first stage drives the calibration mask to move along one of the two directions in which the first detection mark array is arranged, and the moving distance of the calibration mask is equal to the interval between two adjacent first detection marks.
[0015] In some possible embodiments, the first detection marker array is located within the area enclosed by the boundary of the object plane of the objective lens.
[0016] In some possible embodiments, a reference mask is also provided on the side of the first stage facing the lighting device;
[0017] The number of reference masks is multiple, and they are disposed on at least one side of the calibration mask in the second direction; each reference mask is provided with a second detection mark array;
[0018] When the illumination device is turned on, the image side of the objective lens forms a second marker image array corresponding to the second detection marker array, and the interval between two adjacent second marker images in the second marker image array is equal to the interval between two adjacent alignment detection channels;
[0019] The first stage can drive the reference mask to move, so as to determine the position deviation of the corresponding second mark image relative to the zero position of each alignment detection channel through each alignment detection channel, and determine the displacement error of the first stage.
[0020] In some possible embodiments, the second marker image array includes at least two second marker groups, the at least two marker groups being arranged at intervals along the second direction, and each second marker group including a plurality of second marker images arranged along the first direction and the second direction;
[0021] When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side. In the first direction, the distance between the two second marker images located at both ends is greater than or equal to the size of the objective lens exposure field of view in the first direction.
[0022] In some possible embodiments, an energy sensor is also included; the energy sensor is disposed on the side of the second stage facing the objective lens;
[0023] The number of the calibration mask is at least one, and each calibration mask is further provided with a first light-transmitting hole array. The opening parameters of the light-transmitting holes in the first light-transmitting hole array of each calibration mask are different. The opening parameters include at least one of the size, distribution position and number of light-transmitting holes.
[0024] A target measurement position is set on the first platform, and the calibration mask is placed at the target measurement position;
[0025] When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side. At least part of the illumination light is transmitted into the interior of the objective lens through the plurality of light-transmitting holes. By changing different calibration masks, the size and position distribution of the plurality of light-transmitting holes are changed to simulate the power of the plurality of transmitted light during the exposure operation of the objective lens. In conjunction with the second stage, the energy sensor moves in the objective lens exposure field of view to realize the detection of the power of the plurality of transmitted light.
[0026] In some possible embodiments, a wavefront sensor is also included, which is disposed on the side of the second stage facing the objective lens;
[0027] When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side, and a first marker image array corresponding to the first detection marker array is formed on the image side of the objective lens. The second stage drives the wavefront sensor to move within the objective lens exposure field of view to realize the wavefront aberration detection of the objective lens.
[0028] In some possible embodiments, the second stage moves in a stepping motion along a preset motion path that extends in an S-shape, and the stepping interval of the alignment sensor is N times the interval between two adjacent first marker images, 1≤N≤n, where n is the number of alignment detection channels in the alignment sensor.
[0029] According to a second aspect of this disclosure, a method for testing the performance of an objective lens is provided, the method comprising:
[0030] The illumination device is turned on so that the first detection mark array forms a first mark image array on the image side of the objective lens; wherein, in two adjacent first mark image arrays, at least a portion of the first mark images overlap in position;
[0031] The second stage is driven to move the alignment sensor, and the position deviation of the corresponding first marker image relative to the zero position of each alignment detection channel is determined through each alignment detection channel, so as to realize the aberration detection of the objective lens.
[0032] In some possible embodiments, the method further includes:
[0033] Turn on the lighting;
[0034] The first stage is driven to move the reference mask along the first direction to one side of the objective lens exposure field of view, and the second stage is driven to move the alignment sensor along the first direction from one side to the other side of the objective lens exposure field of view, so that the second detection mark array forms multiple positive second mark image arrays at different positions.
[0035] The first stage is driven to move to the next test station, and the second stage is driven to move the alignment sensor in the opposite direction along the first direction, so that the second detection mark array forms multiple reverse second mark image arrays at different positions; wherein the second stage moves along a preset motion path;
[0036] The position deviation of the corresponding second marker image relative to the zero position of each alignment detection channel is determined by each alignment detection channel to determine the displacement error of the first stage.
[0037] In some possible embodiments, the method further includes:
[0038] The calibration mask is placed on the target measurement position on the first platform; the calibration mask is provided with a first light-transmitting hole array, which includes multiple light-transmitting holes.
[0039] When the illumination device is turned on, at least a portion of the illumination light is transmitted into the interior of the objective lens through the plurality of light-transmitting holes;
[0040] The second stage is driven to move the energy sensor within the objective lens exposure field of view in order to determine the transmitted light power of the objective lens;
[0041] By replacing the calibration mask, the transmitted light power corresponding to the multiple light-transmitting holes under different sizes and distribution positions is simulated, and the transmitted light power is detected in conjunction with the energy sensor.
[0042] In some possible embodiments, the method further includes:
[0043] The illumination device is turned on so that the first detection marker array forms multiple first marker image arrays at different positions; wherein, in two adjacent first marker image arrays, at least part of the first marker images overlap in position;
[0044] The second stage is driven to move the wavefront sensor, so that the wavefront sensor can perform wavefront aberration detection on the objective lens according to the multiple first marker image arrays corresponding to the different positions.
[0045] Implementing this invention has the following beneficial effects:
[0046] In this invention, a multi-channel sensor is set on the second stage. The multi-channel sensor may include at least two channels. At the same time, a detection mark array is set on the calibration mask. The detection mark array can form a mark image array including multiple mark images. The interval between two adjacent alignment detection channels is the same as the interval between two adjacent mark images, so that each channel can synchronously detect multiple adjacent mark image arrays in three dimensions, thereby improving the efficiency of objective lens performance testing.
[0047] In addition, since at least some of the marker images in the adjacent marker image arrays overlap, the positioning error or displacement error of the second stage can be determined based on the position information of the overlapping position. This can avoid the impact of the positioning accuracy or displacement detection accuracy error of the second stage on the objective lens performance test, thereby improving the accuracy and reliability of the objective lens performance test. Attached Figure Description
[0048] To more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0049] Figure 1 This is a schematic diagram of the objective lens performance testing device provided in an embodiment of the present invention.
[0050] Figure 2 A schematic diagram of the structural layout of the calibration mask template provided in the embodiment of the present invention;
[0051] Figure 3 This is a schematic diagram of the layout of the alignment sensor provided in an embodiment of the present invention;
[0052] Figure 4 This is a schematic diagram of the trajectory corresponding to the preset motion path provided in the embodiments of the present invention;
[0053] Figure 5This is a schematic diagram of the structural layout corresponding to the reference mask template provided in an embodiment of the present invention;
[0054] Figure 6 This is a schematic diagram of the motion trajectory corresponding to the reference mask template provided in an embodiment of the present invention.
[0055] The attached figures are labeled as follows:
[0056] 100-lighting devices;
[0057] 200-First stage, 210-Calibration mask, 211-First detection mark array, 212-First mark image array, 213-First light-transmitting aperture array, 220-Reference mask, 221-Second detection mark array, 222-Second mark image array, 223-Second light-transmitting aperture array;
[0058] 300 - Objective lens, 310 - Objective lens exposure field of view, 320 - Coaxial alignment field of view, 330 - Objective lens aperture;
[0059] 400 - Second stage; 410 - Alignment sensor; 420 - Energy sensor; 430 - Wavefront sensor;
[0060] 500 - Preset motion path. Detailed Implementation
[0061] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0062] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.
[0063] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.
[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.
[0065] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.
[0066] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.
[0067] Example 1
[0068] Figure 1 This diagram illustrates the structure of the objective lens performance testing device provided in this embodiment of the invention; please refer to [link / reference]. Figure 1 An objective lens performance testing device, having a first direction, a second direction, and a third direction that are mutually perpendicular to each other, includes:
[0069] An illumination device 100, a first stage 200, an objective lens 300, and a second stage 400 are arranged sequentially at intervals along the third direction. An alignment sensor 410 is provided on the side of the second stage 400 facing the objective lens 300. The alignment sensor 410 has at least two alignment detection channels.
[0070] The first stage 200 is provided with a calibration mask 210 on the side near the illumination device 100. The calibration mask 210 is provided with a first detection mark array 211, which is located within the area enclosed by the boundary of the object plane of the objective lens 300.
[0071] When the illumination device 100 is turned on, the objective lens 300 forms an objective lens exposure field of view 310 and a coaxial alignment field of view 320 on its image side, and forms a first marker image array 212 corresponding to the first detection marker array 211 on the image side of the objective lens 300. A portion of the first marker images in the first marker image array 212 covers the objective lens exposure field of view 310, and another portion of the first marker images covers the coaxial alignment field of view 320. In the coaxial alignment field of view 320, the number of first detection markers is at least two. The interval between two adjacent first marker images in the first marker image array 212 is equal to the interval between two adjacent alignment detection channels.
[0072] The second stage 400 can perform stepping motion along a preset motion path 500, which extends in an S-shape. The stepping interval of the alignment sensor 410 is N times the interval between two adjacent first marker images, where 1 ≤ N ≤ n, and n is the number of alignment detection channels in the alignment sensor 410.
[0073] In a specific embodiment, such as Figure 1 As shown, the first direction is the x-direction, the second direction is the y-direction, and the third direction is the z-direction. The orientation of the objective lens performance testing device is preferably aligned with the coordinate system of the lithography machine, thus eliminating the need for position data conversion during the online testing of the objective lens 300. The objective lens performance testing device may include an illumination device 100, a first stage 200, an objective lens 300, and a second stage 400 spaced apart along the third direction. The illumination device 100 can be any device that meets the performance testing requirements of the objective lens 300, such as a white light illumination device 100 or a coaxial illumination device 100. The illumination device 100 can be selected based on different requirements, considering factors such as light intensity uniformity, spectral range, and stability.
[0074] In this invention, the objective lens performance testing device can be applied to the online testing process or the offline testing process of the objective lens 300. When applied to the online testing process of the objective lens 300, the first stage 200 can be the mask stage included in the lithography machine, and the second stage 400 can be the workpiece stage included in the lithography machine. When applied to the offline testing process of the objective lens 300, the first stage 200 can be a stage for placing the mask template, and the second stage 400 can be a stage for placing multiple sensors and driving the sensors to move.
[0075] Figure 2 This is a schematic diagram of the structural layout of the calibration mask template provided in the embodiments of the present invention; as shown below. Figure 2As shown, a first detection mark array 211 is provided on the calibration mask 210. The first detection mark array 211 includes multiple first detection marks that are uniformly distributed along the first and second directions and have light-transmitting capabilities. The shape, size, and positional distribution of the first detection marks can be adjusted according to the specific performance testing requirements of the objective lens 300. Figure 2 The layout shown is for illustrative purposes only.
[0076] Figure 3 This diagram illustrates the layout of the alignment sensor provided in an embodiment of the present invention; as shown. Figure 3 As shown, the alignment sensor 410 may include multiple detection channels and the multiple detection channels are distributed in two mutually perpendicular directions, such as at least two detection channels or at least three detection channels. The alignment sensor 410 has at least two detection channels in both the first direction and the second direction to achieve synchronous detection of several marker images in the channel.
[0077] When the illumination device 100 is turned on, the objective lens 300 forms an objective lens exposure field of view 310 and a coaxial alignment field of view 320 distributed on both sides of the objective lens exposure field of view 310 along a first direction or a second direction. Both the coaxial alignment field of view 320 and the objective lens exposure field of view 310 are within the objective lens aperture 330, wherein the objective lens aperture 330 is the area enclosed by the boundary of the object plane of the objective lens 300.
[0078] Illumination light can pass through each of the first detection marks in the first detection mark array 211, forming a first mark image array 212 corresponding to the first detection mark array 211 on the image side of the objective lens 300. Since the relative position of the first detection mark array 211 is within the objective lens aperture 330, each mark image in the first mark image array 212 is also distributed within the objective lens exposure field of view 310 and the coaxial alignment field of view 320. In the first mark image array 212, a portion of the first mark images are uniformly distributed within the objective lens exposure field of view 310, and another portion is distributed within the two coaxial alignment fields of view 320. The number of first mark images in the two coaxial alignment fields of view 320 is the same, and each includes at least two first mark images distributed in two directions.
[0079] Arranging the first detection marker array 211 inside the objective lens aperture 330 can ensure accurate imaging position and avoid focus error or image blurring caused by the marker position deviating from the object surface. At the same time, since the imaging deviation of the first marker image directly reflects the degree of distortion of the objective lens 300, the first detection marker is located in the coaxial alignment field of view 320 and the objective lens exposure field of view 310, which can ensure the reference accuracy when detecting distortion.
[0080] like Figure 2-3In this invention, multiple detection channels of the alignment sensor 410 are arranged in a 3x3 configuration. The arrangement direction of each detection channel is consistent with the distribution direction of the first marker image array 212, and the interval between each detection channel is the same as the interval between two adjacent first marker images in the first marker image array 212. This allows each detection channel to perform synchronous position detection of multiple adjacent first marker images in three dimensions. Simultaneously, the relative position deviation between the zero points corresponding to each detection channel of the alignment sensor 410 has been pre-calibrated and detected.
[0081] After the first marker image covers the coaxial alignment field of view 320, its imaging position can be used to calculate and correct alignment errors caused by environmental fluctuations or mask movement. Multiple detection markers are distributed within the coaxial alignment field of view 320, allowing detection in multiple directions. This effectively offsets errors that may arise from single-point detection due to equipment drift or environmental fluctuations, providing more reliable spatial position data and ensuring the stability and accuracy of mask alignment. The marker image can directly reflect changes in parameters such as magnification and distortion of the objective lens 300. By synchronously detecting the marker image covering the coaxial alignment field of view 320, the alignment sensor 410 achieves simultaneous mask alignment and objective lens 300 performance monitoring.
[0082] The second stage 400 can drive the alignment sensor 410 to move, so as to determine the position deviation of the corresponding first mark image relative to the zero position of each alignment detection channel through each alignment detection channel, thereby realizing the aberration detection of the objective lens 300.
[0083] In one specific embodiment, the second stage 400 can perform stepping motion along a preset motion path 500 to drive the alignment sensor 410 to move. The stepping interval of the alignment sensor 410 is N times the interval between two adjacent first marker images, where 1≤N≤n, and n is the number of alignment detection channels in the alignment sensor 410. This allows the alignment sensor 410 to sequentially detect the position deviation of the first marker image relative to the zero position of each alignment detection channel, thereby realizing the detection of aberrations of the objective lens 300, such as distortion, magnification, field curvature, and astigmatism.
[0084] Figure 4 This is a schematic diagram of the trajectory corresponding to the preset motion path provided in the embodiment of the present invention. The trajectory of the preset motion path 500 can be set according to specific objective lens performance testing requirements. In this invention, it is preferably set as an S-shaped trajectory, such as... Figure 4As shown, the preset motion path 500 extends in an S-shape, starting from a marker image of the first marker image array 212, moving to the right along the first direction, then moving upward along the second direction, then moving to the left along the first direction, then moving upward along the second direction, then moving to the right along the first direction, then moving upward along the second direction, then moving to the left along the first direction, then moving upward along the second direction, then moving to the right along the first direction, then moving upward along the second direction, then moving to the left along the first direction, until it reaches a marker image of the first marker image array 212 as the endpoint; wherein, the endpoint and the starting point are determined according to the number of detection channels of the alignment sensor 410, so that the alignment sensor 410 can cover all the first detection markers in one movement along the preset motion path 500.
[0085] Since the performance inspection of objective lens 300 requires high-precision position detection, the S-shaped path can ensure smooth and abrupt motion, reducing interference with the inspection results. The smooth S-shaped path allows the multi-channel alignment sensor 410 to inspect each mask mark image at the same speed and time interval during the movement, thereby ensuring that all marks in the entire field of view are detected. Compared with linear motion, the S-shaped path can cover the entire field of view faster and reduce the return time, thereby saving inspection time and improving work efficiency.
[0086] The objective lens performance testing method corresponding to Embodiment 1 will be described below in conjunction with the above structure.
[0087] The illumination device 100 is turned on so that the first detection mark array 211 forms a first mark image array 212 on the image side of the objective lens 300; wherein, in two adjacent first mark image arrays 212, at least a portion of the first mark images overlap in position;
[0088] The second stage 400 is driven to move the alignment sensor 410. The position deviation of the corresponding first marker image relative to the zero position of each alignment detection channel is determined through each alignment detection channel, so as to realize the aberration detection of the objective lens 300.
[0089] In one specific embodiment, the calibration mask 210 is placed on the first stage 200, such that the first detection mark array 211 is within the objective lens exposure field of view 310, and the mark surface of the first detection mark array 211 coincides with the object surface of the objective lens 300. The illumination device 100 is turned on to illuminate all the marks on the calibration mask 210 within the objective lens exposure field of view 310 and the coaxial alignment field of view 320, so that the objective lens 300 images the first detection mark array 211 onto the image side of the objective lens 300, obtaining the first mark image array 212.
[0090] like Figure 4As shown, the second stage 400, starting from the preset motion path 500, drives the sensor to move along the preset motion path 500 in step intervals, so that each detection channel is simultaneously aligned with the same number of first marker images in the first marker image array 212, and the positional deviation of each first marker image relative to the zero position of each channel in the three-dimensional direction is detected. Since the relative positional deviation between the zero positions of each detection channel of the alignment sensor 410 has been pre-calibrated and detected, the relative positional deviation between the first marker images can be obtained.
[0091] The second stage 400 moves the alignment sensor 410 to the next detection position. Since the movement interval is N times the interval between the first marker images, some of the first marker images will be repeatedly detected between two adjacent detection positions. The relative positional relationship between the remaining first marker images at the two test positions can be determined by the repeatedly detected first marker images. Since the preset movement path 500 enables the alignment sensor 410 to perform alignment and deviation detection on all first marker images, it can ensure that all first marker images are detected, thereby enabling the detection of aberrations such as distortion, magnification, field curvature, astigmatism, and image plane position within the entire exposure field of view of the objective lens 300.
[0092] In this invention, a multi-channel sensor is provided on the second stage 400. The multi-channel sensor may include at least two channels. At the same time, a detection mark array is provided on the calibration mask 210. The detection mark array can form a mark image array including multiple mark images. The interval between two adjacent alignment detection channels is the same as the interval between two adjacent mark images, so that each channel can synchronously detect multiple adjacent mark image arrays in three dimensions, thereby improving the efficiency of objective lens 300 performance testing. Since at least some mark images in adjacent mark image arrays overlap, the positioning error or displacement error of the second stage 400 can be determined based on the position information of the overlapping position. This can avoid the influence of the positioning accuracy or displacement detection accuracy error of the second stage 400 on the objective lens 300 performance testing, thereby improving the accuracy and reliability of objective lens 300 performance testing.
[0093] In addition, the first stage 200 drives the calibration mask 210 to move along one of the two directions in which the first detection mark array 211 is arranged, and the moving distance of the calibration mask 210 is equal to the interval between two adjacent first detection marks.
[0094] In a specific embodiment, the calibration mask 210 is placed on the first stage 200 and this position is determined as the initial position. After the aberration performance of the objective lens 300 is detected at the initial position, the calibration mask 210 is moved by the first stage 200 along two directions of the detection mark arrangement in the first detection mark array 211 (i.e., along the first direction and the second direction, and the moving distance is the interval between two adjacent first detection marks). The aberration performance of the objective lens 300 is detected again at the moved position. This can avoid the influence of the displacement error of the second stage 400 on the performance detection of the objective lens 300, thereby improving the detection accuracy of aberrations of the objective lens 300 such as distortion and field curvature.
[0095] Specifically, when the calibration mask 210 is in its initial position, a performance test of the objective lens 300 is performed using the method described above to obtain test result D0. The first stage 200 moves the calibration mask 210 along the first direction by a distance equal to the interval between two adjacent first detection marks in the first direction. A performance test of the objective lens 300 is performed again to obtain test result D1. Subtracting the two test results D1 from D0 yields the relative positional deviation between two adjacent first detection marks on the calibration mask 210, thus obtaining the relative positional error of all first detection marks in the first detection mark array 211 on the calibration mask 210 in the first direction. Similarly, the first stage 200 moves the calibration mask 210 along the second direction by a distance equal to the interval between two adjacent first detection marks in the second direction. A performance test of the objective lens 300 is performed again to obtain test result D2, which is the relative positional error of all first detection marks in the first detection mark array 211 on the calibration mask 210 in the second direction. This completes the calibration of the detection mark positional error on the calibration mask 210.
[0096] The design of the first stage 200 driving the calibration mask 210 to move in two directions enables the detection device to overcome field of view limitations, eliminate errors, improve detection accuracy and efficiency, and flexibly adapt to different detection needs.
[0097] Example 2
[0098] In addition to the structures described in Embodiment 1 above, the objective lens performance testing device also includes a reference mask 220; specifically, a reference mask 220 is also provided on the side of the first stage 200 facing the illumination device 100.
[0099] The number of reference masks 220 is at least one, and they are disposed on at least one side of the calibration mask 210 in the second direction; each reference mask 220 is provided with a second detection mark array 221 and a second light-transmitting hole array 223;
[0100] When the illumination device 100 is turned on, the image side of the objective lens 300 forms a second marker image array 222 corresponding to the second detection marker array 221. The interval between two adjacent second marker images in the second marker image array 222 is equal to the interval between two adjacent alignment detection channels. The second marker image array 222 includes at least two second marker groups, which are arranged at intervals along the second direction. Each second marker group includes a plurality of second marker images arranged along the first direction. In the first direction, the distance between two second marker images located at both ends is greater than or equal to the size of the objective lens exposure field of view 310 in the first direction.
[0101] In one specific embodiment, the first stage 200 may further include a reference mask 220. Figure 5 This is a schematic diagram of the structural layout corresponding to the reference mask template 220 provided in an embodiment of the present invention; as shown below. Figure 5 As shown, the number of reference masks 220 is at least one, and they can be disposed on at least one side of the calibration mask 210 in the second direction. That is, there is a positional deviation between the reference mask 220 and the calibration mask 210 in the second direction, but there is no deviation between them in the first direction. When there are multiple reference masks 220, they can be disposed on the same side or both sides of the calibration mask 210 in the second direction.
[0102] The reference mask 220 is provided with a second detection mark array 221 and a second light-passing aperture array 223 for supplementing the transmitted light power. In the second detection mark array 221, the distance between the second detection marks located at both ends in the first direction is greater than or equal to the distance of the objective lens exposure field of view 310 in the first direction; in the second direction, the second detection mark array 221 includes at least two mark groups, i.e., as shown... Figure 5 The number of rows in the second detection marker array 221 is greater than or equal to 2.
[0103] In the first direction, the distance between the two ends of the second detection mark array 221 is greater than or equal to the size of the objective lens exposure field of view 310, ensuring that the mark image can cover the entire field of view of the objective lens 300. At the same detection position, the performance of the objective lens 300 in the first direction can be completely detected, avoiding detection blind spots caused by uncovered areas within the field of view. The second detection mark array 221 includes multiple rows of second detection marks, which can refine the detection accuracy in the first direction. At the same time, the larger distance between the marks at both ends provides a wider reference, thereby ensuring full field of view detection, providing high-precision measurement of local details, and reducing the error amplification effect caused by overly concentrated marks.
[0104] The interval between two adjacent second marker images in the second marker image array 222 is equal to the interval between two adjacent alignment detection channels. The first stage 200 can drive the reference mask 220 to move, so as to determine the position deviation of the corresponding second marker image relative to the zero position of each alignment detection channel through each alignment detection channel, and determine the displacement error of the first stage 200.
[0105] In one specific embodiment, the first stage 200 can move a wide range in the second direction to move the reference mask 220 from one side of the objective lens exposure field 310 to the other. The second marker image interval is the same as the detection channel interval, which enables each detection channel of the alignment sensor 410 to be accurately aligned with the imaging point of the corresponding second marker image. Multiple second marker images can be simultaneously detected by multiple detection channels of the alignment sensor 410, avoiding measurement errors caused by time differences. The number of detection channels determines the number of second marker images that can be covered in a single detection, so that multiple second marker images matching the number of detection channels can be detected simultaneously in each measurement, reducing the number of stage movements, thereby reducing the complexity of mechanical movements and improving detection efficiency. In addition, the detection channel interval is consistent with the second marker image interval, avoiding imaging shifts or positional deviations that may occur when mismatched, improving the accuracy of position detection, especially when measuring magnification changes or distortion, it can ensure the accurate measurement of the relative position of each marker image.
[0106] The objective lens performance testing method corresponding to Embodiment 2 will be described below in conjunction with the above structure.
[0107] Turn on the lighting device 100;
[0108] The first stage 200 is driven to move the reference mask 220 along the first direction to one side of the objective lens exposure field of view 310, and the second stage 400 is driven to move the alignment sensor 410 along the first direction from one side to the other side within the objective lens exposure field of view 310, so that the second detection mark array 221 forms a plurality of positive second mark image arrays 222 at different positions.
[0109] The first stage 200 is driven to move to the next test station, and the second stage 400 is driven to move the alignment sensor 410 in the opposite direction along the first direction, so that the second detection mark array 221 forms multiple reverse second mark image arrays 222 at different positions; wherein the second stage 400 moves along a preset motion path 500.
[0110] The displacement error of the first stage 200 is determined by determining the position deviation of the corresponding second marker image relative to the zero position of each alignment detection channel through each alignment detection channel.
[0111] In one specific embodiment Figure 6 This is a schematic diagram of the motion trajectory corresponding to the reference mask template provided in the embodiments of the present invention, such as... Figure 6 As shown, the reference mask 220 is placed on the first stage 200, and after the illumination device 100 is turned on, the first stage 200 moves the reference mask 220 along the first direction to one side of the objective lens exposure field of view 310. The second stage 400 moves the alignment sensor 410 along the first direction from one side of the objective lens exposure field of view 310 to the other side. The position detection of the second detection mark array 221 formed by the objective lens 300 in the forward second mark image array 222 is performed in sequence to obtain the relative positional relationship between the second mark images. The method for determining the relative positional relationship can refer to Embodiment 1, and will not be repeated here.
[0112] Furthermore, the first stage 200 moves the reference mask 220 along the first direction to the next detection station, with a movement interval of k times the interval between adjacent second detection marks, where k is less than the number of arrays of the second detection mark array 221 in the first direction. The second stage 400 moves the alignment sensor 410 along the first direction, with a movement distance of m times the interval between two adjacent positive second mark image arrays 222.
[0113] The second stage 400 again drives the alignment sensor 410 to move in the opposite direction along the first direction, and sequentially performs position detection on the reversed second marker image array 222 formed by the objective lens 300 through the second marker detection array, thereby obtaining the relative positional relationship between the second marker images at this detection station. Similarly, the first stage 200 drives the reference mask 220 to move stepwise from one side of the objective lens exposure field of view 310 to the other side along the first direction, until the second marker image covers the entire objective lens exposure field of view 310. The second stage 400 also drives the alignment sensor 410 to move stepwise, and the movement trajectory can be a preset movement path 500.
[0114] During this process, some second marker images will be repeatedly detected in two adjacent detection positions. The position change of the reference mask template 220 can be obtained through the repeatedly detected second marker images, so as to realize the splicing of the detection station and eliminate the influence of the motion error of the first stage 200.
[0115] The first stage 200 moves the reference mask 220, allowing the second detection mark to gradually enter the objective lens exposure field of view 310, achieving comprehensive detection of the entire objective lens exposure field of view 310. During the movement of the first stage 200, the detection mark array of the reference mask 220 partially overlaps at adjacent positions. The marks in these overlapping areas can be used for repeated detection to correct the movement error of the first stage 200 and improve the accuracy of relative position measurement. In addition, the overlapping areas can be stitched together to construct the performance data of the entire objective lens 300, thereby reducing the detection blind zone caused by the limitation of the objective lens exposure field of view 310. By detecting the same reference mark at different positions, errors introduced by mask movement or environmental changes can be eliminated, improving measurement accuracy.
[0116] Example 3
[0117] In addition to the structures described in Embodiment 1 and / or Embodiment 2 above, the objective lens performance testing device further includes an energy sensor 420; the energy sensor 420 is disposed on the side of the second stage 400 facing the objective lens 300;
[0118] The number of the calibration mask templates 210 is multiple, and each calibration mask template 210 is further provided with a first light-transmitting hole array 213. The opening parameters of the light-transmitting holes in the first light-transmitting hole array 213 of each calibration mask template 210 are different. The opening parameters include at least one of the size, distribution position and number of light-transmitting holes.
[0119] The first stage 200 is provided with a target measurement position, and the calibration mask 210 is placed at the target measurement position;
[0120] In a specific embodiment, such as Figure 2 As shown, the calibration mask 210 is also provided with a first light-transmitting aperture array 213, with multiple first light-transmitting apertures evenly distributed on the calibration mask 210. The light-transmitting aperture array is used to supplement the transmitted light power of the objective lens 300. For different calibration masks 210, the opening parameters of the multiple light-transmitting apertures in the first light-transmitting aperture array 213 are different, that is, at least one of the size, distribution position and number of light-transmitting apertures on different calibration masks 210 is different.
[0121] When the illumination device 100 is turned on, at least part of the illumination light is transmitted into the interior of the objective lens 300 through the plurality of light-transmitting holes. By changing different calibration masks 210, the size and position distribution of the plurality of light-transmitting holes are changed to simulate the multiple transmitted light powers of the objective lens 300 during exposure. In conjunction with the second stage 400, the energy sensor 420 is moved within the objective lens exposure field of view 310 to detect the multiple transmitted light powers.
[0122] In one specific embodiment, the calibration mask 210 is placed at the target measurement position on the first stage 200. At this time, each first detection mark in the first detection mark array 211 on the calibration mask 210 is located within the objective lens exposure field of view 310, and the mark surface of the first detection mark array 211 is located on the object plane of the objective lens 300. After the illumination device 100 is turned on to illuminate the calibration mask 210, the objective lens 300 images the first detection mark array 211 onto the image side of the objective lens 300. At the same time, part of the illumination light is transmitted into the interior of the objective lens 300 through multiple light holes in the first light hole array 213. By switching different calibration masks 210, the size distribution position and number of each light hole can be adjusted to simulate the transmitted light power during the exposure operation of the objective lens 300, ensuring that the transmitted light power inside the objective lens 300 during performance testing is consistent with that during actual exposure.
[0123] Furthermore, the second stage 400 moves the energy sensor 420 so that the energy sensor 420 can detect the light intensity under exposure conditions of the objective lens 300. Its movement trajectory can be the preset movement path 500 in Embodiment 1. Specifically, by detecting the light intensity in the imaging area of the first aperture array 213 compensated for the transmitted light power of the objective lens 300, the light intensity and uniformity of the image plane of the objective lens 300 are detected. Moreover, by adjusting different transmitted light powers, the correspondence between different performance characteristics of the objective lens 300 and the transmitted light power can be determined, and the performance of the objective lens 300 can be adjusted in advance according to different exposure conditions.
[0124] The objective lens performance testing method corresponding to Example 3 will be described below in conjunction with the above structure.
[0125] The calibration mask 210 is placed on the target measurement position on the first stage 200; the calibration mask 210 is provided with a first light-transmitting hole array 213, which includes a plurality of light-transmitting holes.
[0126] When the illumination device 100 is turned on, at least a portion of the illumination light is transmitted into the interior of the objective lens 300 through the plurality of light-transmitting holes.
[0127] The second stage 400 is driven to move the energy sensor 420 within the objective lens exposure field of view 310 to determine the transmitted light power of the objective lens 300.
[0128] Replace the calibration mask 210 to simulate the transmitted light power corresponding to the multiple light-transmitting holes under different sizes and distribution positions, and use the energy sensor 420 to detect the transmitted light power.
[0129] By switching the size, position, and number of different light apertures, the light power distribution through the objective lens 300 can be precisely controlled, simulating various light power conditions of the objective lens 300 during actual exposure work, so as to achieve accurate evaluation of the performance changes of the objective lens 300 under different transmitted light power conditions.
[0130] By switching the calibration mask 210 to adjust the distribution parameters of the light aperture, different testing requirements can be met and testing conditions can be quickly switched without redesigning or adjusting the hardware, thus improving the flexibility of the objective lens 300 performance testing. Adjusting the light aperture array allows for adjustment of the light power distribution, ensuring that the internal transmitted light power of the objective lens 300 under testing conditions is consistent with that under actual exposure. This avoids differences in thermal effects caused by differences in light power between testing conditions and actual conditions, improving the accuracy and consistency of the testing data.
[0131] Example 4
[0132] In addition to the structures described in Embodiments 1, 2 and / or 3 above, the objective lens performance testing device also includes a wavefront sensor 430, which is disposed on the side of the second stage 400 facing the objective lens 300.
[0133] When the illumination device 100 is turned on, the image side of the objective lens 300 forms a first marker image array 212 corresponding to the first detection marker array 211, and in conjunction with the second stage 400, the wavefront sensor 430 moves within the objective lens exposure field of view 310 to achieve wavefront aberration detection of the objective lens 300.
[0134] In one specific embodiment, the objective lens performance testing device further includes a wavefront sensor 430 disposed on the side of the second stage 400 facing the objective lens 300. The wavefront sensor 430 is moved by the second stage 400, thereby realizing the detection of wavefront aberration of the objective lens 300.
[0135] The objective lens performance testing method corresponding to Example 4 will be described below in conjunction with the above structure.
[0136] The illumination device 100 is turned on so that the first detection mark array 211 forms a plurality of first mark image arrays 212 at different positions; wherein, in two adjacent first mark image arrays 212, at least a portion of the first mark images overlap in position;
[0137] The second stage 400 is driven to move the wavefront sensor 430, so that the wavefront sensor 430 can perform wavefront aberration detection on the objective lens 300 according to multiple first marker image arrays 212 corresponding to different positions.
[0138] In one specific embodiment, when performing wavefront aberration detection, the first detection markers on the first detection marker array 211 can be used in conjunction with the wavefront sensor 430 to monitor wavefront aberration changes in the objective lens 300. The second stage 400 can move the wavefront sensor 430 along a preset motion path 500 at step intervals, so that the wavefront sensor 430 can determine the position data of the first marker image corresponding to different positions, thereby realizing wavefront aberration detection of the objective lens 300. The principle and process are the same as in Embodiment 1, only the data acquisition is changed, so it will not be described again.
[0139] The first stage 200 drives the wavefront sensor 430 to move, and aligns it with the first detection mark on the first detection mark array 211 on the calibration mask 210 in sequence. The wavefront sensor 430 is used to detect the wavefront aberration of the objective lens 300, which can improve the accuracy of wavefront aberration detection.
[0140] As can be seen from the embodiments provided by the present invention above, in the present invention, a multi-channel sensor is set on the second stage. The multi-channel sensor may include at least two channels. At the same time, a detection mark array is set on the calibration mask. The detection mark array can form a mark image array including multiple mark images. The interval between two adjacent alignment detection channels is the same as the interval between two adjacent mark images, so that each channel can synchronously detect multiple adjacent mark image arrays in three dimensions, thereby improving the efficiency of objective lens performance detection.
[0141] In addition, since at least some of the marker images in the adjacent marker image arrays overlap, the positioning error or displacement error of the second stage can be determined based on the position information of the overlapping position. This can avoid the impact of the positioning accuracy or displacement detection accuracy error of the second stage on the objective lens performance test, thereby improving the accuracy and reliability of the objective lens performance test.
[0142] It should be noted that the various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technological improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A device for testing the performance of an objective lens, having a first direction, a second direction, and a third direction that are mutually perpendicular to each other, characterized in that, The objective lens performance testing device includes: An illumination device, a first stage, an objective lens, and a second stage are arranged sequentially at intervals along the third direction. An alignment sensor is provided on the side of the second stage facing the objective lens, and the alignment sensor has at least two alignment detection channels. The first platform is provided with a calibration mask on the side near the lighting device, and the calibration mask is provided with a first detection mark array; When the illumination device is turned on, the image side of the objective lens forms a first marker image array corresponding to the first detection marker array, and the interval between two adjacent first marker images in the first marker image array is equal to the interval between two adjacent alignment detection channels. The second stage can drive the alignment sensor to move, so as to determine the position deviation of the corresponding first mark image relative to the zero position of each alignment detection channel through each alignment detection channel, thereby realizing the aberration detection of the objective lens. The objective lens performance testing device further includes: an energy sensor; the energy sensor is disposed on the side of the second stage facing the objective lens; The number of the calibration mask templates is multiple, and each calibration mask template is further provided with a first light-transmitting hole array. The opening parameters of the light-transmitting holes in the first light-transmitting hole arrays of each calibration mask template are different. The opening parameters include at least one of the size, distribution position and number of light-transmitting holes. A target measurement position is set on the first platform, and the calibration mask is placed at the target measurement position; When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side. At least part of the illumination light is transmitted into the interior of the objective lens through multiple light-transmitting holes. By changing different calibration masks, the size and position distribution of the multiple light-transmitting holes are changed to simulate the multiple transmitted light powers of the objective lens during exposure. In conjunction with the second stage, the energy sensor moves within the objective lens exposure field of view to detect the multiple transmitted light powers.
2. The objective lens performance testing device according to claim 1, characterized in that, When the illumination device is turned on, the objective lens forms an objective lens exposure field of view and a coaxial alignment field of view on its image side; A portion of the first marker images in the first marker image array covers the objective lens exposure field of view, and another portion of the first marker images covers the coaxial alignment field of view; In the coaxial alignment field of view, the number of the first detection markers is at least two.
3. The objective lens performance testing device according to claim 1, characterized in that, The first detection marker array is located within the area enclosed by the boundary of the object plane of the objective lens.
4. The objective lens performance testing device according to claim 1, characterized in that, The first stage drives the calibration mask to move along one of the two directions of the first detection mark array, and the moving distance of the calibration mask is equal to the interval between two adjacent first detection marks.
5. The objective lens performance testing device according to claim 1, characterized in that, A reference mask is also provided on the side of the first platform facing the lighting device; The number of reference masks is at least one, and they are disposed on at least one side of the calibration mask in the second direction; each reference mask is provided with a second detection mark array; When the illumination device is turned on, the image side of the objective lens forms an image with the second detection mark array. The corresponding second marker image array, wherein the interval between two adjacent second marker images in the second marker image array is equal to the interval between two adjacent alignment detection channels; The first stage can drive the reference mask to move, so as to determine the position deviation of the corresponding second mark image relative to the zero position of each alignment detection channel through each alignment detection channel, and determine the displacement error of the first stage.
6. The objective lens performance testing device according to claim 5, characterized in that, The second marker image array includes at least two second marker groups, which are arranged at intervals along the second direction, and each second marker group includes a plurality of second marker images arranged along the first direction and the second direction; When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side. In the first direction, the distance between the two second marker images located at both ends is greater than or equal to the size of the objective lens exposure field of view in the first direction.
7. The objective lens performance testing device according to claim 1, characterized in that, It also includes a wavefront sensor, which is disposed on the side of the second stage facing the objective lens; When the illumination device is turned on, the objective lens forms an objective lens exposure field of view on its image side, and a first marker image array corresponding to the first detection marker array is formed on the image side of the objective lens. The second stage drives the wavefront sensor to move within the objective lens exposure field of view to realize the wavefront aberration detection of the objective lens.
8. The objective lens performance testing device according to claim 1 or 7, characterized in that, The second stage is capable of stepping along a preset motion path, which extends in an S-shape. The stepping interval of the alignment sensor is N times the interval between two adjacent first marker images, where 1 ≤ N ≤ n, and n is the number of alignment detection channels in the alignment sensor.
9. A method for testing the performance of an objective lens, applied to the objective lens performance testing apparatus as described in any one of claims 1-8, characterized in that, The method includes: The illumination device is turned on so that the first detection mark array forms a first mark image array on the image side of the objective lens; wherein, in two adjacent first mark image arrays, at least a portion of the first mark images overlap in position; The second stage is driven to move the alignment sensor, and the position deviation of the corresponding first marker image relative to the zero position of each alignment detection channel is determined through each alignment detection channel, so as to realize the aberration detection of the objective lens.
10. The method for testing the performance of an objective lens according to claim 9, characterized in that, The method further includes: Turn on the lighting; The first stage is driven to move the reference mask along the first direction to one side of the objective lens exposure field of view, and the second stage is driven to move the alignment sensor along the first direction from one side to the other side of the objective lens exposure field of view, so that the second detection mark array forms multiple positive second mark image arrays at different positions. The first stage is driven to move to the next test station, and the second stage is driven to move the alignment sensor in the opposite direction along the first direction, so that the second detection mark array forms multiple reverse second mark image arrays at different positions; wherein the second stage moves along a preset motion path; The position deviation of the corresponding second marker image relative to the zero position of each alignment detection channel is determined by each alignment detection channel to determine the displacement error of the first stage.
11. The method for testing the performance of an objective lens according to claim 9, characterized in that, The method further includes: The calibration mask is placed on the target measurement position on the first platform; the calibration mask is provided with a first light-transmitting hole array, which includes multiple light-transmitting holes. When the illumination device is turned on, at least a portion of the illumination light is transmitted into the interior of the objective lens through the plurality of light-transmitting holes; The second stage is driven to move the energy sensor within the objective lens exposure field of view in order to determine the transmitted light power of the objective lens; By replacing the calibration mask, the transmitted light power corresponding to the multiple light-transmitting holes under different sizes and distribution positions is simulated, and the transmitted light power is detected in conjunction with the energy sensor.
12. The method for testing the performance of an objective lens according to claim 9, characterized in that, The method further includes: The illumination device is turned on so that the first detection marker array forms multiple first marker image arrays at different positions; wherein, in two adjacent first marker image arrays, at least part of the first marker images overlap in position; The second stage is driven to move the wavefront sensor, so that the wavefront sensor can perform wavefront aberration detection on the objective lens according to the multiple first marker image arrays corresponding to the different positions.