Test template, detection method and lithography machine for optical system focal plane detection

Abstract

The present application provides a test template, a detection method and a photolithography machine for detecting the focal plane of an optical system, which belongs to the field of photolithography machine technology. Since the test template includes at least one diamond test pattern, this design makes the detection of the focal plane position of the optical system more accurate. The tip of the diamond pattern is very sensitive to changes in the defocus amount, which helps to identify small deviations in the focal plane position. By using this test template, the focal plane position can be quickly detected and adjusted, thereby reducing the debugging time in the production process and improving production efficiency. It should be noted that the design of the test template does not depend on a specific optical system configuration, so it can be widely used in different optical systems, such as photolithography machines, microscopes, etc., for detection and calibration of the focal plane position.

Description

Technical Field

[0001] The present application relates to the technical field of photolithography machines, and in particular to a test template, a detection method, and a photolithography machine for detecting the focal plane of an optical system. Background Art

[0002] The focal plane stability of a lithography machine's objective lens directly impacts key performance indicators such as the machine's Critical Dimension Uniformity (CDU) and overlay accuracy, ultimately affecting the quality of the chips produced. Therefore, regular focal plane monitoring is essential. Due to resolution limitations, when exposing lines of similar resolution, the optical proximity effect causes line corners to round or shrink, shortening the lines. This reduction in line width becomes more pronounced as defocus increases. Based on this principle, the lithography machine's wafer alignment subsystem measures the length of exposed lines corresponding to different defocus values. A mathematical relationship is established between the two, allowing the objective lens' optimal focal plane to be inferred. This ultimately enables real-time monitoring of the lithography machine's optimal focal plane position.

[0003] However, due to the influence of process conditions and measurement errors, the corner changes of traditional horizontal and vertical lines may not be obvious. Summary of the Invention

[0004] The embodiments of the present application provide a test template, a detection method, and a photolithography machine for detecting the focal plane of an optical system. A test template that is very sensitive to changes in the focal plane position of the photolithography machine is designed, and the test template includes a diamond test pattern. When the optimal focal plane is exposed, the image contrast is high, so all the tips of the diamonds can be displayed. As the defocus amount increases, the image contrast decreases significantly, and the tips farther away from the center area of ​​the diamond are more difficult to display. That is, in the embodiments of the present application, by setting such a diamond test pattern with obvious line changes on the test template, the optimal focal plane of the objective lens can be more accurately deduced, thereby ultimately achieving real-time monitoring of the optimal focal plane position of the photolithography machine. Specifically:

[0005] In a first aspect, an embodiment of the present application provides a test template for detecting a focal plane of an optical system. The test template includes:

[0006] carrier;

[0007] The test module is arranged on the carrier and includes at least one diamond-shaped test pattern.

[0008] In the above technical solution, the ratio between the long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern is greater than 10:1.

[0009] In the above technical solution, the test module includes at least one test module group, the test module includes m groups of test units, and each group of test units includes n diamond test patterns, m≥5, n≥4;

[0010] The m groups of test units are distributed in parallel according to the first distribution law at an interval x1;

[0011] n diamond-shaped test patterns are distributed in parallel according to the second distribution rule at an interval of x2;

[0012] Where x1>x2.

[0013] In the above technical solution, the m groups of test units satisfy the following conditions under the first distribution rule: one group of test units in two adjacent groups of test units can be translated horizontally or vertically by a distance x1 and then overlapped with the other group of test units;

[0014] The n diamond test patterns satisfy the second distribution rule: one of two adjacent diamond test patterns can be translated by a distance x2 in the horizontal direction or the vertical direction and then overlap with the other diamond test pattern.

[0015] In the above technical solution, the long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern satisfy: , where k3 is a proportional coefficient with a value between 15 and 30;

[0016] The translation distance x1 between two adjacent groups of test units satisfies: , where k4 is a proportional coefficient with a value between 0.3 and 1;

[0017] The translation distance x2 between two adjacent diamond test patterns satisfies: .

[0018] In the above technical solution, the test module includes q test modules, q≥2, and the diamond test patterns in two adjacent test modules are distributed according to the third distribution rule;

[0019] The two diamond test patterns in two adjacent test modules satisfy the third distribution law: the long diagonal line of the diamond test pattern in one test module extends in the first line extension direction, and the long diagonal line of the diamond test pattern in the other test module extends in the second extension direction, wherein the first extension direction and the second extension direction are different.

[0020] In the above technical solution, the number q of the test modules is four, wherein the four test modules are close to each other end to form a mouth-shaped pattern.

[0021] In the above technical solution, the four test modules include a first test module, a second test module, a third test module and a fourth test module;

[0022] The long diagonal line of the diamond test pattern in the first test module extends in a direction that forms an angle of 90° with the horizontal direction;

[0023] The long diagonal line of the diamond test pattern in the second test module extends in a direction parallel to the horizontal direction;

[0024] The angle between the long diagonal line of the diamond test pattern in the third test module and the horizontal direction is 45 degrees;

[0025] The angle between the long diagonal extension direction of the diamond test pattern in the fourth test module and the horizontal direction is 135°.

[0026] In the above technical solution, the first test module, the second test module, the third test module and the fourth test module each include m groups of test units, and each group of test units includes n diamond test patterns;

[0027] Wherein m=7, n=4.

[0028] In the above technical solution, the test template includes w test modules, w ≥ 5 and w is an odd number, and the w test modules are distributed on the carrier according to the fourth distribution rule;

[0029] The w test modules distributed according to the fourth distribution law constitute an exposure field.

[0030] In the above technical solution, the w test modules satisfy the following conditions under the fourth distribution law: a field-shaped exposure field is formed between the w test modules, and there is a distance between two adjacent test modules.

[0031] In the above technical solution, the number w of the test modules is equal to nine, the nine test modules are spaced apart and divided into three rows, and each row is spaced apart and divided into three test modules.

[0032] In the above technical solution, z exposure fields are provided on the carrier, z ≥ 9, and z is an odd number, and the z exposure fields are distributed on the carrier according to the fifth distribution law;

[0033] The z exposure fields distributed according to the fifth distribution law satisfy: two adjacent exposure fields are close to each other.

[0034] In the above technical solution, the number of exposure fields z is seventeen, and the seventeen exposure fields are divided into five rows, with one exposure field in the first row and the fifth row, and five exposure fields adjacent to each other in the second to fourth rows.

[0035] The exposure field in the first row and the third exposure field in the second row are placed together vertically, and the exposure field in the fifth row and the third exposure field in the fourth row are placed together vertically.

[0036] In the above technical solution, the carrier is a mask used in a photolithography machine.

[0037] A second aspect of the present application provides a method for detecting the focal plane of an optical system using the test template provided in the first aspect of the present application. The detection method includes:

[0038] Expose a diamond-shaped test pattern in a test template at different defocus levels and transfer the exposed pattern to a silicon wafer;

[0039] Measuring pattern line widths corresponding to different defocus amounts, and determining the optimal focal plane position based on the measured multiple pattern line widths;

[0040] The pattern line width is the long diagonal distance of the diamond test pattern after exposure.

[0041] In the above technical solution, the method for determining the optimal focal plane position based on the measured line widths of multiple patterns includes:

[0042] A polynomial fitting is performed based on the measured line widths of the multiple patterns and the corresponding defocus amounts, and the optimal focal plane position is determined based on the fitting result.

[0043] In the above technical solution, the method for determining the optimal focal plane position based on the fitting result includes:

[0044] The defocus amount corresponding to the maximum point of the polynomial is solved within a given defocus amount range, that is, the optimal focal plane position.

[0045] In the above technical solution, a test template is provided with a plurality of exposure fields, each of which is provided with a diamond test pattern, wherein the method of exposing the diamond test pattern in the test template with different defocus amounts includes:

[0046] Multiple exposure fields are exposed in sequence with different defocus amounts. The difference in defocus amount between two adjacent exposure fields is 0.3 μm, and the defocus amount range is -2.4 μm to 2.4 μm.

[0047] In the above technical solution, each exposure field is provided with a plurality of horizontal diamond test patterns with long diagonal lines extending in the horizontal direction, and a plurality of vertical diamond test patterns with long diagonal lines extending in the vertical direction;

[0048] Methods for measuring the line width of a diamond test pattern after exposure include:

[0049] Measuring the pattern line widths of a plurality of horizontal diamond test patterns in each exposure field after exposure, and the pattern line widths of a plurality of vertical diamond test patterns in each exposure field after exposure, to obtain a plurality of sets of horizontal and vertical line width measurement values;

[0050] A horizontal average value is calculated based on the multiple sets of horizontal line width measurement values ​​obtained, and a vertical average value is calculated based on the multiple sets of vertical line width measurement values ​​obtained.

[0051] In the above technical solution, the method for obtaining the average horizontal line width based on the obtained multiple sets of horizontal line width measurement values ​​includes: removing the maximum and minimum values ​​from the multiple sets of horizontal line width measurement values, and averaging the remaining multiple sets of horizontal line width measurement values ​​to obtain the average horizontal line width value;

[0052] and / or

[0053] The method for obtaining the average vertical line width based on the obtained multiple sets of vertical line width measurement values ​​includes: removing the maximum and minimum values ​​in the multiple sets of vertical line width measurement values, and averaging the remaining multiple sets of vertical line width measurement values ​​to obtain the average vertical line width value.

[0054] In the above technical solution, the method of performing polynomial fitting based on the measured multiple pattern line widths and the corresponding defocus amounts includes:

[0055] Multiple horizontal line width average values ​​and multiple vertical line width average values ​​of multiple exposure fields are obtained, and polynomial fitting is performed using a fitting equation based on the obtained multiple horizontal line width average values ​​and the corresponding exposure defocus amounts, and a horizontal fitting equation is obtained. Polynomial fitting is performed using a fitting equation based on the obtained multiple vertical line width average values ​​and the corresponding exposure defocus amounts, and a vertical fitting equation is obtained. The optimal focal plane position is determined based on the horizontal fitting equation and the vertical fitting equation.

[0056] In the above technical solution, the method for determining the optimal focal plane position based on the horizontal direction fitting equation and the vertical direction fitting equation includes:

[0057] The least squares method is used to solve the horizontal fitting equation and the vertical fitting equation respectively, and the horizontal solution equation and the vertical solution equation are obtained. The optimal defocus amount is solved for the horizontal solution equation and the optimal defocus amount is solved for the vertical solution equation, and the optimal focal plane position is determined based on the solution results.

[0058] A third aspect of the embodiments of the present application provides a lithography machine, which includes the test template provided in the first aspect of the embodiments of the present application and / or the detection method provided in the second aspect of the embodiments of the present application.

[0059] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0060] In the embodiment of the present application, a test template is designed that is very sensitive to changes in the focal plane position of a lithography machine. Since the test template includes at least one diamond test pattern, this design makes the detection of the focal plane position of the optical system more accurate. The tip of the diamond pattern is very sensitive to changes in the defocus amount, which helps to identify small deviations in the focal plane position. By using this test template, the focal plane position can be quickly detected and adjusted, thereby reducing the debugging time in the production process and improving production efficiency. It should be noted that the design of the test template does not depend on a specific optical system configuration, so it can be widely used in different optical systems, such as lithography machines, microscopes, etc., for detection and calibration of the focal plane position. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a schematic diagram of the structure of the test unit in the embodiment of the present application;

[0062] Figure 2 This is a schematic diagram of the structure of the test module in the embodiment of the present application;

[0063] Figure 3 This is a schematic diagram of the structure of the test module in the embodiment of the present application;

[0064] Figure 4 This is a schematic structural diagram of the exposure field in the embodiment of the present application;

[0065] Figure 5 This is a schematic diagram of the structure of the test template in the embodiment of the present application;

[0066] Figure 6 2 is a diagram showing the relationship between the horizontal and vertical diamond test patterns and the defocus amount in the embodiment of the present application.

[0067] in:

[0068] 10-carrier;

[0069] 20-exposure field; 200-test module; 2000-test module; 2000a-first test module; 2000b-second test module; 2000c-third test module; 2000d-fourth test module; 20000-test unit; 20001-diamond test pattern. DETAILED DESCRIPTION

[0070] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0071] Throughout the specification and claims, the following terms have at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms, but merely provide illustrative examples of the terms.

[0072] In the description of the present invention, the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may. Similarly, the phrase "in some embodiments," as used herein, when used multiple times, does not necessarily refer to the same embodiment, although it may. As used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or" unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described unless the context clearly dictates otherwise. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The scope of the present invention is limited solely by the scope of the appended claims, and any examples set forth in this specification are not intended to be limiting but merely illustrative of some of the many possible embodiments of the claimed invention. The various embodiments provided herein should not be construed as limiting the scope of the invention.

[0073] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0074] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0075] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0076] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0077] like Figures 1-6 As shown, the first aspect of the embodiment of the present application provides a test template for detecting the focal plane of an optical system, and the test template includes:

[0078] carrier 10;

[0079] The test module 200 is disposed on the carrier 10 , and the test module 200 includes at least one diamond-shaped test pattern 20001 .

[0080] Since the test module 200 in the embodiment of the present application includes at least one diamond-shaped test pattern 20001, this design makes the detection of the focal plane position of the optical system more accurate. The tip of the diamond pattern is very sensitive to changes in the defocus amount, which helps to identify slight deviations in the focal plane position. By using this test template, the focal plane position can be quickly detected and adjusted, thereby reducing the debugging time in the production process and improving production efficiency. It should be noted that the design of the test template does not depend on a specific optical system configuration, so it can be widely used in different optical systems, such as lithography machines, microscopes, etc., for detection and calibration of the focal plane position.

[0081] For example, the test template is set on the silicon wafer carrier 10 of the lithography machine, including a test module 200, which contains a diamond test pattern 20001. The test template is exposed using a lithography machine, and the pattern is transferred to the silicon wafer through an optical system. The tip imaging quality of the diamond test pattern 20001 is measured, the pattern changes under different defocus amounts are detected, and test data under different defocus amounts are collected. The data is analyzed to determine the optimal focal plane position, and the focal plane position of the lithography machine is adjusted according to the analysis results to ensure that the focal plane position reaches the optimal state.

[0082] Furthermore, in some possible implementations, the ratio between the long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern 20001 is greater than 10:1.

[0083] In the embodiment of the present application, since the ratio of the long diagonal to the short diagonal of the diamond test pattern is greater than 10:1, this means that the diamond pattern is very slender. Such a design makes the pattern more sensitive to changes in the focal position, because any slight defocus will cause the imaging quality of the diamond tip to drop significantly. This high sensitivity helps to accurately detect the focal position of the optical system. Specifically, when the focal position of the elongated diamond pattern is inaccurate, the imaging of its tip will deteriorate rapidly, which makes it easier and more accurate for the optical system to identify the focal error. This is especially important for optical systems {such as lithography machines} that require high-precision focusing, because they need to ensure the precise transfer of the pattern. By using diamond patterns with extremely high aspect ratios, the accuracy and reliability of the detection results can be improved. This is because when the focal position is optimal, these slender tips can be clearly imaged, and when the focal position deviates, the degradation in imaging quality will be very obvious, making the detection results more reliable.

[0084] Further, in some possible implementations, referring to Figure 2 The test module 200 includes at least one test module 2000 , the test module 2000 includes m groups of test units 20000 , and each group of test units 20000 includes n diamond test patterns 20001 , where m≥5 and n≥4;

[0085] The m groups of test units 20,000 are distributed in parallel according to the first distribution rule at an interval of x1;

[0086] The n diamond-shaped test patterns 20001 are distributed in parallel with an interval x2 according to the second distribution rule;

[0087] Where x1>x2.

[0088] In the embodiment of the present application, at least one test module 2000 is provided, each test module comprising multiple groups of test units 20000, each group of test units comprising multiple diamond-shaped test patterns 20001. This structural design enables the test template to detect the focal position from multiple positions and angles. This comprehensive detection helps improve the accuracy of identifying changes in the focal position.

[0089] Furthermore, the intervals {x1 and x2} between the test units 20000 and the diamond test patterns 20001 are arranged according to a specific distribution rule, where x1>x2. This layout ensures that the test patterns do not interfere with each other while maintaining sufficient spacing for accurate measurement.

[0090] Furthermore, by configuring m groups of test cells 20000 and n diamond-shaped test patterns 20001 within each group, the test template can adapt to different exposure fields and different inspection requirements. The minimum values ​​of m and n {m ≥ 5, n ≥ 4} ensure that the test template has enough test points to cover the exposure field while also providing flexibility to accommodate different test conditions.

[0091] That is, this structural design allows multiple test units to be inspected simultaneously during one exposure process, thereby reducing the number of exposures and test time and improving production efficiency.

[0092] Further, in some possible implementations, referring to Figure 2 , m groups of test units 20000 satisfy the following under the first distribution rule: one group of test units 20000 in two adjacent groups of test units 20000 can overlap with the other group of test units 20000 after being translated by a distance x1 in the horizontal direction or vertical direction;

[0093] The n diamond test patterns 20001 satisfy the following requirement under the second distribution rule: one of two adjacent diamond test patterns 20001 can be translated by a distance x2 in the horizontal direction or the vertical direction and then overlap with the other diamond test pattern 20001 .

[0094] In the embodiments of the present application, by specifying the distribution pattern of the test units 20000 and the diamond-shaped test patterns 20001, it is possible to ensure consistency and repeatability in tests performed across different exposure fields. This consistency is crucial for precisely controlling the focal position of the optical system. By enabling adjacent test units 20000 and diamond-shaped test patterns 20001 to overlap after being translated horizontally or vertically by a specific distance, it is possible to ensure that the test patterns are evenly distributed across the entire carrier 10. This uniform distribution helps improve the test pattern's coverage of the entire exposure field. Since the distribution pattern of the test units 20000 and the diamond-shaped test patterns 20001 is fixed, it helps reduce random errors that may occur during the testing process, thereby enhancing the reliability of the test results.

[0095] Furthermore, in some possible implementations, the long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern 20001 satisfy the following: , where k3 is a proportional coefficient with a value between 15 and 30;

[0096] The translation distance x1 between two adjacent groups of test units 20000 satisfies: , where k4 is a proportional coefficient with a value between 0.3 and 1;

[0097] The translation distance x2 between two adjacent diamond test patterns 20001 satisfies: .

[0098] In the embodiment of the present application, by setting the proportional relationship between the long diagonal distance L1 and the short diagonal distance L2 { , where k3 is a proportional coefficient between 15-30}, the size ratio of the diamond test pattern can be precisely controlled. This precise control helps ensure the high sensitivity of the test pattern to the defocus amount, thereby improving the accuracy of the focus plane detection. By setting the translation distance x1 between two adjacent groups of test units 20000, , where k4 is a proportional coefficient between 0.3 and 1} and the translation distance x2 between two adjacent diamond test patterns 20001{ }, the distribution of test patterns across the entire test template can be optimized. This optimization helps improve test template utilization efficiency and comprehensiveness of detection.

[0099] By precisely controlling the size ratio and distribution spacing of the test patterns, the consistency and repeatability of the results between different tests can be enhanced. This is crucial for ensuring the reliability and accuracy of optical system focus plane inspection.

[0100] It should be noted that when the above-mentioned test template is set on the silicon wafer carrier 10 of the lithography machine, the short diagonal distance L2 of the diamond test pattern in the test template satisfies: Determined, where k1 is a process constant, and its value can be within the range of 0.15 to 0.5; k2 is a proportionality coefficient, and its value can be within the range of 1 to 1.5; λ is the wavelength of the light source of the lithography machine; NA is the numerical aperture of the projection objective, and its value can be within the range of 0.6 to 1.35.

[0101] Further, in some possible implementation manners, the test module 200 includes q test modules 2000, q≥2, and the diamond test patterns 20001 in two adjacent test modules 2000 are distributed according to a third distribution rule;

[0102] Among them, two diamond test patterns 20001 in two adjacent test modules 2000 satisfy the following under the third distribution rule: the long diagonal of the diamond test pattern 20001 in one test module 2000 extends in the first line extension direction, and the long diagonal of the diamond test pattern 20001 in the other test module 2000 extends in the second extension direction, where the first extension direction and the second extension direction are different.

[0103] In the embodiment of the present application, by including at least two test modules 2000 in the test module 200 and distributing the diamond test patterns 20001 according to the third distribution rule, the third distribution rule allows the diamond test patterns in adjacent test modules to be arranged in different extension directions. This design allows the test template to implement more detection points in a limited space, and at the same time avoids the mutual interference between the test patterns. This optimization helps to improve the utilization efficiency of the test template, so as to achieve more comprehensive detection in a limited space.

[0104] Further, in some possible implementation manners, the number q of the test modules 2000 is four, and the four test modules 2000 are enclosed in a shape of a Chinese character 'kou' with the heads and tails close to each other.

[0105] In the embodiment of the present application, by enclosing the four test modules 2000 into a shape of a Chinese character 'kou', the space on the carrier 10 can be utilized more effectively. This layout method can maximize the coverage range of the test patterns and reduce the unused space at the same time.

[0106] It should be noted that for the shape of a Chinese character 'kou' mentioned in the embodiment of the present application, its core lies in forming a layout roughly presenting the shape of a Chinese character 'kou' through the arrangement of the four test modules 2000. This layout does not require a strict geometric shape, but emphasizes a basic arrangement structure, in which the four test modules are connected end to end to enclose a shape similar to the Chinese character 'kou'.

[0107] Furthermore, in some possible implementations, the four test modules 2000 include a first test module 2000a, a second test module 2000b, a third test module 2000c, and a fourth test module 2000d;

[0108] The long diagonal line of the diamond test pattern 20001 in the first test module 2000a forms an angle of 90° with the horizontal direction;

[0109] The long diagonal line of the diamond test pattern 20001 in the second test module 2000b extends in parallel with the horizontal direction;

[0110] The angle between the long diagonal line of the diamond test pattern 20001 in the third test module 2000c and the horizontal direction is 45°.

[0111] The angle between the long diagonal extension direction of the diamond test pattern 20001 in the fourth test module 2000d and the horizontal direction is 135°.

[0112] In the embodiment of the present application, by setting the diamond test patterns 20001 in the first test module 2000a to the fourth test module 2000d to different extension directions, a comprehensive detection of the focal plane of the optical system in different directions is achieved. This all-round detection helps to capture anisotropic errors that may exist in the optical system. Specifically, the angles between the long diagonal extension direction of the diamond test pattern in each test module and the horizontal direction are 90°, 0°, 45° and 135° respectively. Such a design can more accurately detect the focal plane performance of the optical system in different directions, thereby improving the detection accuracy. By setting test patterns in different directions, the focal plane position of the optical system can be more accurately calibrated to ensure that optimal performance can be achieved in all directions, which is particularly important for high-precision optical systems.

[0113] Furthermore, in some possible implementations, the first test module 2000a, the second test module 2000b, the third test module 2000c, and the fourth test module 2000d each include m groups of test units 20000, and each group of test units 20000 includes n diamond-shaped test patterns 20001.

[0114] Wherein m=7, n=4.

[0115] In the embodiment of the present application, by providing seven groups of test units in each test module, each group containing four diamond-shaped test patterns, the number of test points can be increased, thereby enhancing the level of detail in focus position detection. More test points facilitate more accurate identification and calibration of the focus position.

[0116] Further, in some possible embodiments, the test template includes w test modules 200, where w ≥ 5 and w is an odd number, and the w test modules 200 are distributed on the carrier 10 according to the fourth distribution rule;

[0117] Among them, the w test modules 200 distributed according to the fourth distribution rule form an exposure field 20.

[0118] In the embodiments of the present application, by distributing at least 5 test modules on the carrier 10 and the number being odd, the accuracy and reliability of the focal plane detection can be improved. An odd number of test modules helps to reduce the error caused by the symmetry of the number of test modules, making the evaluation of the focal plane position more accurate.

[0119] Further, in some possible embodiments, the w test modules 200 satisfy the following under the fourth distribution rule: an "L-shaped" exposure field 20 is formed between the w test modules 200, and there is a distance between two adjacent test modules 200.

[0120] In the embodiments of the present application, by arranging the test modules 200 in an "L-shaped" pattern, the layout of the exposure field 20 can be optimized. The "L-shaped" layout provides a balanced distribution of the test pattern, which helps to achieve more uniform focal plane detection within the exposure field. The "L-shaped" layout ensures an appropriate interval between the test modules, which helps to reduce the mutual interference between the test patterns, thereby improving the detection accuracy. The appropriate interval also helps to more accurately evaluate the focal plane position of each test module.

[0121] It should be noted that the "L-shaped" layout mentioned in the embodiments of the present application refers to the arrangement of the test modules 200 on the carrier 10 that generally presents a shape similar to the Chinese character "L". This layout does not require strict geometric symmetry, but emphasizes a basic arrangement structure, in which the test modules are distributed in a balanced manner to achieve specific technical effects.

[0122] Further, in some possible embodiments, the number w of the test modules 200 is equal to nine, and the nine test modules 200 are spaced apart and arranged in three rows, and three test modules 200 are spaced apart in each row.

[0123] In the embodiments of the present application, by spacing apart the nine test modules and arranging them in three rows with three in each row, the layout of the test modules within the exposure field 20 can be precisely controlled. This precise layout helps to achieve the uniformity and consistency of the focal plane detection within the exposure field. The layout of three rows and three columns can maximize the utilization efficiency of the test modules within the exposure field, making full use of the space within the exposure field while avoiding the mutual interference between the test modules.

[0124] Furthermore, in some possible implementations, z exposure fields 20 are provided on the carrier 10, where z ≥ 9 and z is an odd number, and the z exposure fields 20 are distributed on the carrier 10 according to the fifth distribution rule;

[0125] The z exposure fields 20 distributed according to the fifth distribution rule satisfy: two adjacent exposure fields 20 are close to each other.

[0126] In the embodiment of the present application, by providing at least nine exposure fields on the carrier 10, and with an odd number, the comprehensiveness and uniformity of focus plane detection across the entire carrier can be improved. An odd number of exposure fields helps reduce errors caused by the symmetry of the number of exposure fields, resulting in more accurate assessment of the focus plane position. Exposure fields arranged according to the fifth distribution rule, with adjacent exposure fields close together, help optimize the layout of the exposure fields on the carrier, resulting in more efficient use of the exposure fields.

[0127] Furthermore, in some possible implementations, the number z of exposure fields is seventeen, and the seventeen exposure fields 20 are divided into five rows, with one exposure field 20 in the first row and the fifth row, and five exposure fields 20 adjacent to each other in the second row to the fourth row.

[0128] The exposure fields 20 in the first row and the third exposure field 20 in the second row are placed vertically together, and the exposure field 20 in the fifth row and the third exposure field 20 in the fourth row are placed vertically together.

[0129] In the embodiments of the present application, by specifically specifying the number and distribution of exposure fields, the layout of the exposure fields on the carrier 10 can be precisely controlled. This precise control helps achieve uniform and consistent focus detection within the exposure fields. The arrangement of 17 exposure fields can cover most areas of the carrier 10, improving the coverage and accuracy of focus position detection. This layout ensures that all key areas on the carrier are effectively detected. The five-row layout maximizes the space utilization efficiency within the exposure fields, ensuring full utilization of the space within the exposure fields while avoiding interference between exposure fields.

[0130] Furthermore, in some possible implementations, the carrier 10 is a mask used in a photolithography machine.

[0131] In the embodiment of the present application, by setting a high-sensitivity diamond test pattern on the mask, the focal plane position of the lithography machine can be accurately detected to ensure the pattern transfer accuracy during the lithography process.

[0132] For example, when a photolithography machine is needed to manufacture high-precision chip patterns on a silicon wafer, the test template described above can be used to arrange 17 exposure fields on the mask. Each exposure field contains multiple test modules, each test module contains multiple test module groups and test units, and each test unit contains multiple diamond test patterns. The long diagonal extension direction of these diamond test patterns varies according to the different test modules in which they are located, so as to achieve all-round focus detection. By measuring the imaging quality of these test patterns, the optimal focus position of each exposure field on the entire silicon wafer can be quickly and accurately determined, thereby improving the accuracy and efficiency of the photolithography process. For example, if the focus position of a certain exposure field is inaccurate, resulting in blurred chip patterns, by using this test template, the problem can be quickly identified and the focus position of the photolithography machine can be adjusted to ensure that the chip patterns produced subsequently are clear and accurate.

[0133] Furthermore, the second aspect of the embodiment of the present application further provides a method for detecting the focal plane of an optical system using the test template provided in the first aspect of the embodiment. The detection method includes:

[0134] Expose a diamond-shaped test pattern in a test template at different defocus levels and transfer the exposed pattern to a silicon wafer;

[0135] Measuring pattern line widths corresponding to different defocus amounts, and determining the optimal focal plane position based on the measured multiple pattern line widths;

[0136] The pattern line width is the long diagonal distance of the diamond test pattern after exposure.

[0137] In the embodiments of the present application, by exposing a diamond-shaped test pattern in a test template at different defocus values ​​and transferring the exposed pattern to a silicon wafer, the line width of the pattern corresponding to different defocus values ​​can be accurately measured. This method can accurately determine the optimal focal plane position of the optical system, thereby improving the accuracy of the photolithography process. That is, by measuring the long diagonal distance of the diamond-shaped test pattern after exposure, the performance of the optical system at different focal plane positions can be evaluated. This method helps to optimize the performance of the optical system and ensure that the photolithography operation is performed at the optimal focal plane position.

[0138] For example, a photolithography machine is used to expose a diamond-shaped test pattern in a test template at different defocus values. The exposed pattern is then transferred to a silicon wafer. The line widths of the pattern corresponding to the different defocus values ​​are measured, i.e., the long diagonal distance of the exposed diamond-shaped test pattern. Based on the measured line widths of the multiple patterns, the optimal focal position is determined through data analysis. This typically involves polynomial fitting or other mathematical methods to find the optimal matching point between line width and defocus value. Based on this optimal focal position, the focus of the photolithography machine is adjusted to ensure that subsequent photolithography operations are performed at the optimal focal position.

[0139] Furthermore, in some possible implementations, the method for determining the optimal focal plane position based on the measured line widths of multiple patterns includes:

[0140] A polynomial fitting is performed based on the measured line widths of the multiple patterns and the corresponding defocus amounts, and the optimal focal plane position is determined based on the fitting result.

[0141] In the embodiments of the present application, polynomial fitting can be used to more accurately extract the relationship between line width and defocus from the measurement data. This method can help identify at which defocus the pattern line width reaches the optimal value, thereby determining the optimal focal plane position.

[0142] Furthermore, in some possible implementations, the method for determining the optimal focal plane position based on the fitting result includes:

[0143] The defocus amount corresponding to the maximum point of the polynomial is solved within a given defocus amount range, that is, the optimal focal plane position.

[0144] In the embodiments of the present application, by solving the polynomial maximum point, it is possible to accurately determine at which defocus value the line width of the exposure pattern reaches its optimal state, thereby improving the accuracy of focus plane detection. Specifically, the defocus value corresponding to the maximum point provides a clear focus plane position, making the focus position adjustment of the optical system more certain and reliable.

[0145] Furthermore, in some possible implementations, a test template is provided with a plurality of exposure fields, each of which is provided with a diamond test pattern, wherein the method of exposing the diamond test pattern in the test template at different defocus amounts includes:

[0146] Multiple exposure fields are exposed in sequence with different defocus amounts. The difference in defocus amount between two adjacent exposure fields is 0.3 μm, and the defocus amount range is -2.4 μm to 2.4 μm.

[0147] In this embodiment, by setting the defocus difference to 0.3μm during exposure, exposure can be performed at finer defocus intervals, allowing for more precise adjustment and determination of the optimal focus position. The defocus range is set from -2.4μm to 2.4μm, covering defocus conditions from negative to positive, facilitating accurate detection and determination of the optimal focus position of the optical system.

[0148] Furthermore, in some possible implementations, each exposure field is provided with a plurality of horizontal diamond test patterns with long diagonal lines extending in the horizontal direction, and a plurality of vertical diamond test patterns with long diagonal lines extending in the vertical direction;

[0149] Methods for measuring the line width of a diamond test pattern after exposure include:

[0150] Measuring the pattern line widths of a plurality of horizontal diamond test patterns in each exposure field after exposure, and the pattern line widths of a plurality of vertical diamond test patterns in each exposure field after exposure, to obtain a plurality of sets of horizontal and vertical line width measurement values;

[0151] A horizontal average value is calculated based on the multiple sets of horizontal line width measurement values ​​obtained, and a vertical average value is calculated based on the multiple sets of vertical line width measurement values ​​obtained.

[0152] In the embodiment of the present application, by measuring the line width of multiple horizontal and vertical diamond test patterns in each exposure field and calculating the average value, the error that may be caused by a single measurement point can be reduced and the measurement accuracy can be improved. By simultaneously evaluating the line width in the horizontal and vertical directions, the focal plane position can be evaluated more comprehensively to ensure that the focal plane position of the optical system in all directions is optimal. The acquisition of multiple sets of measurement values ​​and the calculation of the average value enhance the reliability of data analysis and help to more accurately determine the optimal focal plane position. Accurately evaluating the focal plane position helps to optimize the photolithography process, improve the quality and consistency of the photolithography pattern, and thus improve the overall manufacturing process level.

[0153] Furthermore, in some possible implementations, the method for obtaining an average horizontal line width based on the obtained multiple sets of horizontal line width measurement values ​​includes: removing the maximum and minimum values ​​from the multiple sets of horizontal line width measurement values, and averaging the remaining multiple sets of horizontal line width measurement values ​​to obtain an average horizontal line width value;

[0154] and / or

[0155] The method for obtaining the average vertical line width based on the obtained multiple sets of vertical line width measurement values ​​includes: removing the maximum and minimum values ​​in the multiple sets of vertical line width measurement values, and averaging the remaining multiple sets of vertical line width measurement values ​​to obtain the average vertical line width value.

[0156] In the embodiments of the present application, by removing the maximum and minimum values ​​from multiple sets of measurements, the impact of extreme values ​​on the average can be reduced, making the calculated average more accurate and more representative of the true situation of the majority of measurements. This method helps to eliminate outliers that may be caused by measurement errors or other factors, thereby enhancing the reliability of data analysis. An accurate line width average is crucial for determining the optimal focal plane position. By improving the accuracy of the line width average, the accuracy of focal plane detection can be improved, thereby optimizing the lithography process.

[0157] Furthermore, in some possible implementations, a method for performing polynomial fitting based on the measured multiple pattern line widths and corresponding defocus amounts includes:

[0158] Multiple horizontal line width average values ​​and multiple vertical line width average values ​​of multiple exposure fields are obtained, and polynomial fitting is performed using a fitting equation based on the obtained multiple horizontal line width average values ​​and the corresponding exposure defocus amounts, and a horizontal fitting equation is obtained. Polynomial fitting is performed using a fitting equation based on the obtained multiple vertical line width average values ​​and the corresponding exposure defocus amounts, and a vertical fitting equation is obtained. The optimal focal plane position is determined based on the horizontal fitting equation and the vertical fitting equation.

[0159] In the embodiments of the present application, polynomial fitting is performed on the average line widths in the horizontal and vertical directions, respectively, to obtain fitting equations for both directions. This method can more accurately describe the relationship between line width and defocus, thereby improving fitting accuracy. Based on the fitting equations in both directions, the optimal focal plane position can be determined more accurately. This method helps ensure that the focal plane position of the optical system is optimal in all directions.

[0160] For example, in the semiconductor manufacturing process, it is necessary to accurately detect the focal position of the lithography machine, which can be achieved through the following steps:

[0161] 1. Exposure and measurement:

[0162] In each exposure field, multiple diamond-shaped test patterns in the horizontal and vertical directions are set and exposed at different defocus amounts.

[0163] The line widths of multiple horizontal and vertical diamond test patterns in each exposure field are measured to obtain multiple sets of horizontal and vertical line width measurement values.

[0164] 2. Calculate the average:

[0165] For the horizontal direction (ie, H direction), the maximum and minimum values ​​in multiple sets of horizontal line width measurement values ​​are removed, and the remaining multiple sets of horizontal line width measurement values ​​are averaged to obtain the average horizontal line width value.

[0166] For the vertical direction (ie, V direction), the maximum and minimum values ​​in multiple sets of vertical line width measurement values ​​are removed, and the remaining multiple sets of vertical line width measurement values ​​are averaged to obtain the average value of the vertical direction line width.

[0167] 3. Polynomial fitting:

[0168] Multiple horizontal line width averages and multiple vertical line width averages of multiple exposure fields are obtained.

[0169] A polynomial fitting is performed using a fitting equation based on the obtained average values ​​of multiple horizontal line widths and the corresponding exposure defocus amounts, and a horizontal fitting equation is obtained.

[0170] A polynomial fitting is performed using a fitting equation based on the obtained average values ​​of multiple vertical line widths and the corresponding exposure defocus amounts, and a vertical fitting equation is obtained.

[0171] 4. Determine the optimal focal position:

[0172] The optimal focal plane position is determined based on the horizontal direction fitting equation and the vertical direction fitting equation.

[0173] According to the determined optimal focal plane position, the focal plane position of the lithography machine is adjusted to ensure that subsequent lithography operations are performed at the optimal focal plane position.

[0174] Furthermore, in some possible implementations, the method for determining the optimal focal plane position based on the horizontal direction fitting equation and the vertical direction fitting equation includes:

[0175] The least squares method is used to solve the horizontal fitting equation and the vertical fitting equation respectively, and the horizontal solution equation and the vertical solution equation are obtained. The optimal defocus amount is solved for the horizontal solution equation and the optimal defocus amount is solved for the vertical solution equation, and the optimal focal plane position is determined based on the solution results.

[0176] In the embodiments of the present application, the accuracy of the solution can be improved by using the least squares method to solve the fitting equations in the horizontal and vertical directions. The least squares method is a mathematical optimization technique that finds the best function matching the data by minimizing the sum of squared errors. Solving the equations for the optimal defocus value in both directions separately can more accurately determine the optimal focal plane position, ensuring that the focal plane position of the optical system is optimal in all directions.

[0177] For example, when the above-mentioned test pattern and test method are needed to determine the optimal focal plane position of the lithography machine objective lens, it mainly includes the following steps:

[0178] S1: Design and process a mask with the above-mentioned diamond test pattern:

[0179] S2: Place the mask in the lithography machine and expose 17 exposure fields in sequence with different defocus values. The difference between the defocus values ​​of two adjacent exposure fields is 0.3 μm, and the defocus value range is -2.4 μm to +2.4 μm. Figure 5 ;

[0180] S3: Each exposure field measures the diagonals of the 9 diamond patterns in the H direction (i.e. horizontal direction) and the V direction (i.e. vertical direction) in sequence along the S route, obtaining 9 groups of test values ​​in the H direction and the V direction, referring to Figure 4 ;

[0181] S4: The H-direction test values ​​in step S3 are processed as follows: the maximum and minimum values ​​are removed, and the average of the remaining seven groups of test values ​​is calculated as the final test result of the H-direction of the exposure field. The V-direction test values ​​are processed in the same manner.

[0182] S5: Measure the diamond patterns in the 17 exposure fields in step S2 in sequence along the S route. Each exposure field is processed according to steps S3 and S4 to obtain 17 final test results in the H direction and V direction.

[0183] S6: Perform polynomial fitting on the final test results δH and δV in the H direction and V direction in each exposure field and the corresponding defocus amount δf in step S2. The fitting equation is as follows:

[0184] H direction: δH = a1 + b1δf + c1δf^2 + d1δf^3 + e1δf^4

[0185] V direction: δV = a2 + b2δf + c2δf^2 + d2δf^3 + e2δf^4, where a1, a2, b1, b2, c1, c2, d1, d2, e1, e2, etc. are the coefficients of the polynomial

[0186] S7: Solve the equations in the H direction and the V direction in step S6 using the least squares method. The results are as follows:

[0187] δH = 6.5821 - 0.2518δf - 3.0133δf^2 + 0.0668δf^3 + 0.4737δf^4

[0188] δV = 6.4389 - 0.2116δf - 2.9962δf^2 + 0.0539δf^3 + 0.4723δf^4;

[0189] S8: Solve the equations for the H direction and the V direction in step S7 for the optimal defocus amount, and the results are as follows:

[0190] H_f = -0.042μm, V_f = -0.047μm;

[0191] S9: Draw curves for the final test results in the H direction and V direction in S5, such as Figure 6 shown.

[0192] Thus, the optimal focal position of the lithography machine objective lens is finally obtained.

[0193] Furthermore, the third aspect of the embodiment of the present application also provides a lithography machine, which includes the test template provided in the first aspect of the embodiment of the present application and / or the detection method provided in the second aspect of the embodiment of the present application.

[0194] In the above embodiments of the present application, the descriptions of the various embodiments have their own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The steps shown in the relevant flow charts can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flow charts, in some cases, the steps shown or described can be executed in an order different from that shown here. In other words, the order of steps described in the foregoing embodiments is only an example, and reasonable adjustment of the order of steps based on the content of the embodiments of the present application is also within the scope of protection of the embodiments of the present application.

[0195] The sequence of the serial numbers or introduction of the embodiments of this application is for description only and does not represent the superiority or inferiority of the embodiments.

[0196] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0197] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A test template for detecting the focal plane of an optical system, characterized in that: The test template includes: carrier (10); A test module (200), the test module (200) being arranged on the carrier (10), and the test module (200) comprising at least one diamond-shaped test pattern (20001); The test module (200) comprises at least one test module (2000), the test module (2000) comprises m groups of test units (20000), and each group of test units (20000) comprises n diamond-shaped test patterns (20001), where m≥5 and n≥4; m groups of test units (20000) are distributed in parallel with the first distribution law at interval x1; The n diamond test patterns (20001) are distributed in parallel according to a second distribution rule at an interval of x2; Where x1>x2; m groups of test units (20000) satisfy under the first distribution law: one group of test units (20000) in two adjacent groups of test units (20000) can be translated by a distance x1 in the horizontal direction or vertical direction and then overlap with the other group of test units (20000); The n diamond test patterns (20001) satisfy the following under the second distribution rule: one of the two adjacent diamond test patterns (20001) can be translated by a distance x2 in the horizontal direction or vertical direction to overlap with the other diamond test pattern (20001).

2. The test template according to claim 1, wherein: The ratio between the long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern (20001) is greater than 10:

1.

3. The test template according to claim 2, wherein: The long diagonal distance L1 and the short diagonal distance L2 of the diamond test pattern (20001) satisfy the following relationship: L1=k3*L2, where k3 is a proportional coefficient with a value between 15 and 30; The translation distance x1 between two adjacent groups of test units (20000) satisfies: x1=k4*L1, where k4 is a proportional coefficient with a value between 0.3 and 1; The translation distance x2 between two adjacent diamond test patterns (20001) satisfies: x2=2*L2.

4. The test template according to any one of claims 1 to 3, characterized in that: The test module (200) comprises q test modules (2000), q≥2, and the diamond test patterns (20001) in two adjacent test modules (2000) are distributed according to a third distribution rule; The two diamond test patterns (20001) in two adjacent test modules (2000) satisfy the following conditions under the third distribution law: the long diagonal line of the diamond test pattern (20001) in one of the test modules (2000) extends in a first extension direction, and the long diagonal line of the diamond test pattern (20001) in the other test module (2000) extends in a second extension direction, wherein the first extension direction and the second extension direction are different.

5. The test template according to claim 4, wherein: The number q of the test modules (2000) is four, wherein the four test modules (2000) are close together end to end to form a mouth-shaped pattern.

6. The test template according to claim 5, characterized in that: The four test modules (2000) include a first test module (2000a), a second test module (2000b), a third test module (2000c) and a fourth test module (2000d); The long diagonal extension direction of the diamond test pattern (20001) in the first test module (2000a) forms an angle of 90° with the horizontal direction; The long diagonal extension direction of the diamond test pattern (20001) in the second test module (2000b) is parallel to the horizontal direction; The angle between the long diagonal extension direction of the diamond test pattern (20001) in the third test module (2000c) and the horizontal direction is 45°; An angle of 135° is formed between the extending direction of the long diagonal line of the diamond test pattern (20001) in the fourth test module (2000d) and the horizontal direction.

7. The test template according to claim 6, wherein: The first test module (2000a), the second test module (2000b), the third test module (2000c) and the fourth test module (2000d) each include m groups of the test units (20000), and each group of the test units (20000) includes n diamond test patterns (20001); Wherein m=7, n=4.

8. The test template according to any one of claims 1 to 3, characterized in that: The test template includes w test modules (200), w≥5 and w is an odd number, and the w test modules (200) are distributed on the carrier (10) according to a fourth distribution rule; The w test modules (200) distributed according to the fourth distribution law constitute an exposure field (20).

9. The test template according to claim 8, wherein: The w test modules (200) satisfy the following under the fourth distribution rule: a field-shaped exposure field (20) is formed between the w test modules (200), and a distance is provided between two adjacent test modules (200).

10. The test template according to claim 9, wherein: The number w of the test modules (200) is equal to nine, and the nine test modules (200) are spaced apart and arranged into three rows, and three test modules (200) are spaced apart in each row.

11. The test template according to claim 8, wherein: The carrier (10) is provided with z exposure fields (20), z ≥ 9, and z is an odd number, and the z exposure fields (20) are distributed on the carrier (10) according to a fifth distribution rule; The z exposure fields (20) distributed according to the fifth distribution law satisfy the following requirement: two adjacent exposure fields (20) are close to each other.

12. The test template according to claim 11, wherein: The number z of the exposure fields is seventeen, and the seventeen exposure fields (20) are divided into five rows, wherein the first row and the fifth row each have one exposure field (20), and the second row to the fourth row each have five exposure fields (20) adjacent to each other in sequence; The exposure field (20) in the first row and the third exposure field (20) in the second row are attached to each other vertically, and the exposure field (20) in the fifth row and the third exposure field (20) in the fourth row are attached to each other vertically.

13. The test module according to claim 1, wherein: The carrier (10) is a mask plate used in a photolithography machine.

14. A method for detecting the focal plane of an optical system using the test template according to any one of claims 1 to 13, characterized in that: The detection method comprises: Expose a diamond-shaped test pattern in a test template at different defocus levels and transfer the exposed pattern to a silicon wafer; Measuring pattern line widths corresponding to different defocus amounts, and determining the optimal focal plane position based on the measured multiple pattern line widths; The pattern line width is the long diagonal distance of the diamond test pattern after exposure.

15. The method according to claim 14, characterized in that The method for determining the optimal focal plane position according to the measured line widths of multiple patterns includes: A polynomial fitting is performed based on the measured line widths of the multiple patterns and the corresponding defocus amounts, and the optimal focal plane position is determined based on the fitting result.

16. The method according to claim 15, characterized in that The method for determining the optimal focal plane position based on the fitting result includes: The defocus amount corresponding to the maximum point of the polynomial is solved within a given defocus amount range, that is, the optimal focal plane position.

17. The method according to any one of claims 14 to 16, characterized in that The test template is provided with a plurality of exposure fields, each of which is provided with a diamond test pattern, wherein the method of exposing the diamond test pattern in the test template with different defocus amounts includes: Multiple exposure fields are exposed in sequence with different defocus amounts. The difference in defocus amount between two adjacent exposure fields is 0.3 μm, and the defocus amount range is -2.4 μm to 2.4 μm.

18. The method according to claim 17, characterized in that Each exposure field is provided with a plurality of horizontal diamond test patterns with long diagonal lines extending in the horizontal direction, and a plurality of vertical diamond test patterns with long diagonal lines extending in the vertical direction; The method for measuring the line width of a diamond test pattern after exposure comprises: Measuring the pattern line widths of a plurality of horizontal diamond test patterns in each exposure field after exposure, and the pattern line widths of a plurality of vertical diamond test patterns in each exposure field after exposure, to obtain a plurality of sets of horizontal and vertical line width measurement values; A horizontal average value is calculated based on the multiple sets of horizontal line width measurement values ​​obtained, and a vertical average value is calculated based on the multiple sets of vertical line width measurement values ​​obtained.

19. The method according to claim 18, characterized in that The method for obtaining an average horizontal line width based on the obtained multiple sets of horizontal line width measurement values ​​includes: removing the maximum and minimum values ​​from the multiple sets of horizontal line width measurement values, and averaging the remaining multiple sets of horizontal line width measurement values ​​to obtain an average horizontal line width value; and / or The method for obtaining the average vertical line width based on the obtained multiple sets of vertical line width measurement values ​​includes: removing the maximum and minimum values ​​in the multiple sets of vertical line width measurement values, and averaging the remaining multiple sets of vertical line width measurement values ​​to obtain the average vertical line width value.

20. The method according to claim 19, characterized in that The method for performing polynomial fitting based on the measured multiple pattern line widths and corresponding defocus amounts includes: Multiple horizontal line width average values ​​and multiple vertical line width average values ​​of multiple exposure fields are obtained, and polynomial fitting is performed using a fitting equation based on the obtained multiple horizontal line width average values ​​and the corresponding exposure defocus amounts, and a horizontal fitting equation is obtained. Polynomial fitting is performed using a fitting equation based on the obtained multiple vertical line width average values ​​and the corresponding exposure defocus amounts, and a vertical fitting equation is obtained. The optimal focal plane position is determined based on the horizontal fitting equation and the vertical fitting equation.

21. The method according to claim 20, characterized in that The method for determining the optimal focal plane position based on the horizontal direction fitting equation and the vertical direction fitting equation includes: The least squares method is used to solve the horizontal fitting equation and the vertical fitting equation respectively, and the horizontal solution equation and the vertical solution equation are obtained. The optimal defocus amount is solved for the horizontal solution equation and the optimal defocus amount is solved for the vertical solution equation, and the optimal focal plane position is determined based on the solution results.

22. A photolithography machine, characterized in that: The test template comprises any one of claims 1-13.

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