Pose determination method of horizontal sensor and calibration method

Abstract

The invention belongs to the technical field of photoetching calibration, and particularly relates to a pose determination method of a horizontal sensor and a calibration method. The invention provides a method for determining the pose of a horizontal sensor, which is suitable for a stepping photoetching machine adopting a backward binocular sensor. Setting a reference mask plate configured with a calibration mask pattern and a reference substrate configured with a calibration exposure pattern; calibrating the reference mask plate and the reference substrate through a sensor arranged on one side of the mask plate; based on the calibration, the pose relation of the horizontal sensor is obtained; the measurement precision of the horizontal sensor can be improved, and the registration precision of the photoetching process is effectively improved through offset compensation.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithography calibration, and particularly relates to a method for determining the pose of a horizontal sensor and a calibration method. Background Art

[0002] In an exposure machine (lithography machine), a light source irradiates a mask, and then projects the pattern on the mask onto the photoresist on a substrate through a lens to initiate a chemical reaction. With the progress of technology, lithography machines have evolved from the initial proximity-contact exposure to step-and-scan exposure. The light source does not project the entire pattern on the mask onto the wafer at once. The exposure system irradiates the mask through a slit-shaped exposure band, and the workpiece stage carrying the mask moves in one direction under the slit, and the exposure system scans the mask. Synchronized with the scanning of the mask, the wafer moves in the opposite or the same direction. A higher scanning speed can shorten the exposure time, thereby improving the production capacity of the lithography machine. To improve the alignment accuracy, the ratio of the mask image to the wafer image generally adopts size ratios of 1:1, 2:1, 3:1, 4:1 or 1:2. When the moving stage moves, there will be a deflection in the horizontal direction. Therefore, a high-precision horizontal sensor is required to measure the deflection amount in the horizontal direction, and corresponding compensation is performed during movement to reduce the error in the horizontal direction and improve the alignment accuracy.

[0003] Currently, horizontal sensors generally adopt back-to-back binocular sensors, and the horizontal deflection amount between the mask and the wafer is obtained by measuring special patterns on the mask and the wafer. The calibration of the relative position of the optical center coordinates of the two cameras of the binocular sensor will directly affect the measurement result. Traditional binocular calibration generally has overlapping fields of view. By taking left and right views of the same special pattern and extracting multiple matching feature point pairs, according to the epipolar constraint, the corresponding fundamental matrix or essential matrix is solved, and finally the relative motion parameters of the two cameras are obtained.

[0004] Since the two cameras are installed back-to-back in the vertical direction, there is no common viewing area between the two cameras. How to perform high-precision global calibration on non-common-view binocular cameras has become the key to the binocular measurement system. The commonly used global calibration methods are as follows: (1) The mirror method uses an optical mirror to allow the camera to indirectly observe the marked pattern through the mirror to achieve global calibration of non-common-view binocular cameras. However, as the distance between the cameras increases, the image of the marked pattern becomes smaller, resulting in a decrease in accuracy. (2) The motion model method establishes the corresponding relationship between the fields of view of different cameras by tracking the targets in the surrounding environment. By calculating the target trajectory and statistically analyzing the time difference between exiting the field of view of one camera and entering the field of view of another camera, the external parameters of the camera can be estimated. This method requires scene information during calibration, and the accuracy still needs to be improved. Summary of the Invention

[0005] In view of this, the present invention proposes a method for determining the pose of a horizontal sensor applicable to a step-and-scan lithography machine using a back-to-back binocular sensor; a reference reticle with a calibrated mask pattern and a reference substrate with a calibrated exposure pattern are provided; then, the reference reticle and the reference substrate are calibrated by a sensor disposed on one side of the reticle; and then, based on this calibration, the pose relationship of the horizontal sensor is obtained; the measurement accuracy of the horizontal sensor can be improved, and the alignment accuracy of the lithography process can be effectively improved through offset compensation.

[0006] To achieve the above technical objectives, the specific technical solutions adopted by the present invention are as follows:

[0007] A method for determining the pose of a horizontal sensor, the horizontal sensor includes a first sensor and a second sensor that are fixedly arranged back to back, and are used for measuring the motion parameters between the reticle and the substrate of a step-and-expose device;

[0008] The pose determination method includes the following steps:

[0009] S101: Configure a reference reticle and a reference substrate; a calibrated mask pattern is set on the reference reticle, and a calibrated exposure pattern is set on the reference substrate; the calibrated exposure pattern is used to display the exposure position state of calibrating at least a part of the calibrated mask pattern in an ideal environment;

[0010] S102: Install the reference reticle and the reference substrate on the reticle installation position and the substrate installation position respectively;

[0011] S103: Set a third sensor that can penetrate the reference reticle to sense the calibrated exposure pattern and can sense the calibrated mask pattern; from the side of the reference reticle away from the reference substrate, measure the calibrated mask pattern and the calibrated exposure pattern through the third sensor, and obtain the reference relative position relationship between at least one selected point of the mask pattern and the calibrated exposure pattern corresponding to the selected point;

[0012] S104: Based on the first sensor and the second sensor, measure the calibrated mask pattern and the calibrated exposure pattern to obtain the offset relative position relationship between the selected point and the corresponding point of the selected point on the calibrated exposure pattern; based on the reference relative position relationship and the offset relative position relationship, calculate the relative pose between the first sensor and the second sensor.

[0013] Further, the first sensor, the second sensor, and the third sensor are all vision devices; the reference reticle is a transparent reticle.

[0014] Further, the third sensor is a double telecentric lens.

[0015] Further, when the scaling factor between the calibrated exposure pattern and the calibrated mask pattern is 1, the method for obtaining the reference relative position relationship is as follows:

[0016] Based on the third sensor, measure the horizontal pixel offset between the corresponding point and the selected point; thereby obtaining the reference relative position relationship.

[0017] Further, when the scaling factor between the calibrated exposure pattern and the calibrated mask pattern is not 1, the method for obtaining the reference relative position relationship is as follows:

[0018] Based on the third sensor, measure the horizontal pixel offset between the corresponding point and the selected point;

[0019] Substitute the magnification ratio between the calibrated exposure pattern and the calibrated mask pattern into the horizontal pixel offset to obtain the reference relative position relationship.

[0020] Further, when a lens or a lens group with a magnification ratio not equal to 1 is provided between the reference mask and the reference substrate; the method for obtaining the reference relative position relationship is as follows:

[0021] Based on the third sensor, measure the horizontal pixel offset between the corresponding point and the selected point;

[0022] Substitute the internal parameters of the third sensor and the distortion parameters of the lens or the lens group into the pixel offset; thereby obtaining the reference relative position relationship.

[0023] Further, the method for calculating the relative pose is as follows:

[0024] Assume that the reference offset includes a horizontal offset (Δx, Δy); select a fixed point P in the world coordinate system, and assume the coordinates are P w (x, y, z); the field-of-view parameters of the first sensor and the second sensor include internal parameters and external parameters; the internal parameters include the fundamental matrix radial distortion (k 1 , k 2 , k 3 ) and tangential distortion (p 1 , p 2 ); the external parameter is the relative pose, which is described by the rotation matrix and the translation vector T = (t 1 , t 2 , t 3 ); assume (x, y) is the physical coordinate of the image plane, then: T

[0025] ​

[0026] Let the world coordinate system at the selected point be P 1 (X, Y 1 , Z 1 ), and the world coordinate system of the corresponding point be P 2 (X 2 , Y 2 , Z 2 ). Project P 1 and P 2 onto the coordinate systems of the first sensor and the second sensor respectively:

[0027]

[0028] Let the pose transformation from the first sensor to the second sensor be R 12 and T 11 . The coordinate system under the first sensor is converted to the coordinate system under the second sensor as:

[0029]

[0030] Solve for the horizontal pixel offset (Δx 1 and P 2 ) between points P 2 , Δy 2 ) in the coordinate system of the first sensor; that is:

[0031]

[0032] Based on the size of the image of the calibrated exposure pattern, calculate the actual size corresponding to each pixel on the second sensor. Let the scaling factor be s, then:

[0033]

[0034] Furthermore, the R 12 and T 12 are obtained based on no less than 6 groups of corresponding selected points - corresponding points.

[0035] The present invention also proposes a calibration method for calibrating the mask and the substrate during the step - and - scan lithography process. Based on the above - mentioned pose determination method, the calibration method includes the following steps:

[0036] S201: Calibrate the horizontal sensor based on the relative pose;

[0037] S202: During the step - and - scan process of the step - and - scan lithography apparatus, calibrate the relative position relationship between the mask and the substrate based on the calibrated horizontal sensor. Brief Description of the Drawings

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0039] Figure 1 It is a schematic structural diagram of a lithography assembly with a magnification ratio of 1 between the mask and the substrate in the specific embodiment of the present invention;

[0040] Figure 2 It is a schematic structural diagram of a lithography assembly with a lens with a magnification ratio of 0.25 provided between the mask and the substrate in the specific embodiment of the present invention;

[0041] Wherein: 1. Horizontal sensor; 11. First sensor; 12. Second sensor; 2. Third sensor; 3. Reference mask; 31. Calibration mask pattern; 4. Reference substrate; 41. Calibration exposure pattern; 5. Lens. Specific embodiments

[0042] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings.

[0043] The following illustrates the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0044] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present invention, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. Additionally, this apparatus can be implemented and this method can be practiced using other structures and / or functionality in addition to one or more of the aspects described herein.

[0045] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. Only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0046] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0047] In an embodiment of the present invention, a method for determining the pose of a horizontal sensor 1 is proposed, which is characterized in that the horizontal sensor 1 includes a first sensor 11 and a second sensor 12 that are fixedly arranged facing away from each other and are used for measuring the motion parameters between the mask and the substrate of a step exposure device;

[0048] The pose determination method includes the following steps:

[0049] S101: Configure a reference mask 3 and a reference substrate 4; a calibration mask pattern 31 is provided on the reference mask 3, and a calibration exposure pattern 41 is provided on the reference substrate 4; the calibration exposure pattern 41 is used to display the exposure position state of calibrating at least a part of the calibration mask pattern 31 in an ideal environment;

[0050] S102: Install the reference mask 3 and the reference substrate 4 on the mask installation position and the substrate installation position respectively;

[0051] S103: Set a third sensor 2 that can penetrate the reference mask 3 to sense the calibration exposure pattern 41 and can sense the calibration mask pattern 31; from the side of the reference mask 3 away from the reference substrate 4, measure the calibration mask pattern 31 and the calibration exposure pattern 41 through the third sensor 2 to obtain the reference relative position relationship between at least one selected point of the mask pattern and the calibration exposure pattern 41 corresponding to the selected point;

[0052] S104: Measure the calibration mask pattern 31 and the calibration exposure pattern 41 based on the first sensor 11 and the second sensor 12, and obtain the offset relative position relationship between the selected points and the corresponding points of the selected points on the calibration exposure pattern 41; Calculate the relative pose between the first sensor 11 and the second sensor 12 based on the reference relative position relationship and the offset relative position relationship.

[0053] In this embodiment, the horizontal sensor 1 adopts two sets of first sensors 11 and second sensors 12 arranged back to back, which respectively detect the mask installation position and the substrate installation position; Generally, a reference pattern or reference point for identifying position information is provided on one side of the mask of step-by-step lithography facing the substrate. The calibration mask pattern 31 in this embodiment is similar to the reference pattern or reference point, and can be set on the side of the mask away from the substrate installation surface, or on the side of the mask close to the substrate installation position, or embedded in the mask. In this embodiment, it is only necessary to ensure that the third sensor 2 can penetrate the reference mask 3 and detect the calibration mask pattern 31. The calibration exposure pattern 41 in this embodiment is preferably set on the side of the reference substrate 4 facing the mask, and a plurality of calibration exposure patterns 41 are provided corresponding to a plurality of reference mask patterns, so as to calibrate the lithography position of the calibration exposure pattern 41 during the step-by-step lithography process. The number of the calibration exposure patterns 41 in this embodiment can be less than the number of the calibration mask patterns 31.

[0054] In this embodiment, after the reference mask 3 and the reference substrate 4 are respectively installed at the mask installation position and the substrate installation position in the position of simulating the lithography process; The reference mask 3 and the reference substrate 4 are initially aligned, which can be adjusted by the machine or manually. Due to the high precision of lithography, the calibration exposure pattern 41 and the reference mask pattern cannot be completely aligned. Therefore, it is necessary to calibrate the calibration exposure pattern 41 and the reference mask pattern once through the third sensor 2 to obtain the reference relative position relationship.

[0055] The offset relative position relationship in this embodiment is obtained based on the first sensor 11 and the second sensor 12; As Figure 1 、 2 shown, the first sensor 11 detects the calibration mask pattern 31 on the reference mask 3, and the second sensor 12 detects the calibration exposure pattern 41 on the reference substrate 4; The offset relative position relationship between the calibration mask pattern 31 and the calibration exposure pattern 41 is obtained. Then, based on the difference relationship between the reference relative position relationship and the offset relative position relationship, the relative pose of the first sensor 11 and the second sensor 12 is determined by the reference relative position relationship.

[0056] Since the first sensor 11 and the second sensor 12 are arranged in a facing-away manner and do not have a common field of view, and the mask is generally made of non-transparent material; the relative pose obtained by using the pose determination method of this embodiment can avoid the problem of inaccurate calibration of the mask pattern and the exposure pattern caused by the pose deviation of the horizontal sensor 1. In this embodiment, the first sensor 11, the second sensor 12, and the third sensor 2 adopt waveform detectors, and the detection relationship with the calibration mask pattern 31 and the calibration exposure pattern 41 only needs to meet the above functions, and this embodiment does not make specific limitations.

[0057] In one embodiment, the first sensor 11, the second sensor 12, and the third sensor 2 are all vision devices; the reference mask 3 is a transparent mask.

[0058] At the same time, the calibration mask pattern 31 and the calibration exposure pattern 41 of this embodiment both adopt coatings or marker blocks that can be detected by their respective corresponding sensors.

[0059] In one embodiment, the third sensor 2 is a double telecentric lens. The double telecentric lens can avoid the detection deviation between the calibration mask pattern 31 and the calibration exposure pattern 41 caused by different focal lengths.

[0060] In one embodiment, when the scaling factor between the calibration exposure pattern 41 and the calibration mask pattern 31 is 1, the method for obtaining the reference relative position relationship is:

[0061] Based on the third sensor 2, measure the horizontal pixel offset between the corresponding point and the selected point; obtain the reference relative position relationship.

[0062] This embodiment uses pixel offset to measure the reference relative position relationship, which has high precision and can obtain the absolute position relationship between the calibration mask pattern 31 and the calibration exposure pattern 41 after substituting the world coordinates. Since the scaling ratio is 1, the measured pixel offset is the absolute pixel offset.

[0063] In one embodiment, when the scaling factor between the calibration exposure pattern 41 and the calibration mask pattern 31 is not 1, the method for obtaining the reference relative position relationship is:

[0064] Based on the third sensor 2, measure the horizontal pixel offset between the corresponding point and the selected point;

[0065] Substitute the magnification ratio between the calibration exposure pattern 41 and the calibration mask pattern 31 into the horizontal pixel offset to obtain the reference relative position relationship.

[0066] Since the scaling ratio is not 1, the measured pixel offset in this embodiment needs to be substituted into the magnification ratio for calculation before the absolute pixel offset can be obtained.

[0067] Since a lens 5 or a lens group with a magnification factor other than 1 is provided between the reference mask 3 and the reference substrate 4, the measured pixel offset needs to be calculated by substituting the distortion parameter to obtain the absolute pixel offset.

[0068] In one embodiment, the calculation method of the relative pose is as follows:

[0069] Let the reference offset include the horizontal offsets (Δx, Δy); take a fixed point P in the world coordinate system, and let the coordinates be P w (x, y, z); the field-of-view parameters of the first sensor 11 and the second sensor 12 include internal parameters and external parameters; the internal parameters include the fundamental matrix radial distortion (k 1 , k 2 , k 3 ) and tangential distortion (p 1 , p 2 ); the external parameter is the relative pose, which is described by the rotation matrix and the translation vector T = (t 1 , t 2 , t 3 ); let (x, y) be the physical coordinates of the image plane, then: T Let the world coordinate system of the selected point be P

[0070]

[0071] Let the world coordinate system of the selected point be P 1 (X, Y 1 , Z 1 ), and the world coordinate system of the corresponding point be P 2 (X 2 , Y 2 , Z 2 ). Project P 1 and P 2 onto the coordinate systems of the first sensor 11 and the second sensor 12 respectively:

[0072]

[0073] Let the pose transformation from the first sensor 11 to the second sensor 12 be R 12 and T 12 . The coordinate system under the first sensor 11 is converted to the coordinate system under the second sensor 12 as:

[0074]

[0075] Solve for the horizontal pixel offset (Δx between the points P 1 and P 2 in the coordinate system of the first sensor 112 , Δy 2 ); that is:

[0076]

[0077] Based on the size of the image of the calibration exposure pattern 41, calculate the actual size corresponding to each pixel on the second sensor 12. Let the scaling factor be s, then:

[0078]

[0079] The pose calculation method of this embodiment generally calibrates the parameters and absolute position of the first sensor 11 first, and then fits the absolute position of the second sensor 12 with the first sensor 11; the relative pose is obtained during this process.

[0080] In this embodiment, R 12 and T 12 are obtained based on no less than 6 groups of corresponding selected points - corresponding points. Since the change from the first sensor 11 to the second sensor 12 in this embodiment is an Euclidean transformation, the degree of freedom is 6, and at least 6 points' offset amounts need to be measured to calibrate R 12 and T 12 . In this embodiment, by measuring the horizontal offset amounts of 30 groups of corresponding selected points - corresponding points, an over - determined system of equations can be obtained, and then the optimal solution of the transformation matrix can be obtained through the least - squares method or the Levenberg - Marquardt non - linear optimization algorithm.

[0081] In one embodiment, as Figure 2 shown, when there is a lens 5 or a lens group with a magnification not equal to 1 between the reference mask 3 and the reference substrate 4; the method for obtaining the reference relative position relationship is:

[0082] Based on the third sensor 2, measure the horizontal pixel offset amount between the corresponding points and the selected points;

[0083] Substitute the internal parameters of the third sensor 2 and the distortion parameters of the lens 5 or the lens group into the horizontal pixel offset amount; obtain the reference relative position relationship.

[0084] For the convenience of description, in this embodiment, it is assumed that the size ratio of the mask pattern to the wafer pattern is 4:1. At this time, since the lens 5 will introduce image scaling and distortion when the camera captures an image. Therefore, there will be differences in calibrating the first sensor 11 and the third sensor 2 compared with the above embodiment. First, during the use of the third sensor 2, the pattern on the wafer is projected onto the camera plane through the lens 5 and the mask, while the marked pattern of the mask is directly projected onto the camera plane. When calibrating the internal and external parameters of the third sensor 2 relative to the wafer, it can be calibrated in two cases. The first case is when there is no lens 5. The internal parameter K of the third sensor 2 is calibrated on the mask plane 3 and the external parameter [R 3 |T 3 . The second case is when there is a lens 5. The internal parameter K of the third sensor 2 is calibrated on the wafer plane 3t and the external parameter [R 3t |T 3t . At this time, it is equivalent to calibrating the lens 5 and the camera lens as a whole. The calibration method can adopt the Zhang Zhengyou calibration method. When calculating the offset, first, the wafer marked pattern and the mask marked pattern in the same image need to be segmented into two corresponding images; then, the image of the marked pattern on the wafer is corrected according to the internal parameter K 3t and the corresponding distortion parameters, and the image of the marked pattern on the mask is corrected according to the internal parameter K 3 and the corresponding distortion. At this time, the coordinate systems of both are the coordinate values in the camera coordinate system. Subtracting them gives the offset between the mask and the wafer in the camera coordinate system; finally, the offset is converted into the horizontal offset (Δx, Δy) in the wafer coordinate system through the internal parameter K 3t and the external parameter [R 3t |T 3t of the third sensor 2. Measure the offset in the wafer coordinate system field by field to obtain the offsets of evenly distributed points on the entire wafer, and then through a linear correction model, obtain the second-order correction parameters, that is, the offset values of any point can be obtained.

[0085] Secondly, there will be certain differences in the imaging of the wafer marks on the second sensor 12 and the third sensor 2. In this embodiment, the magnification of the lens 5 is 4 times. Therefore, in the third sensor 2, the imaging of the wafer marked pattern will be magnified four times. While in the second sensor 12, the imaging light path does not pass through the lens 5. The internal parameter K of the second sensor 12 2 and the external parameter [R 2 |T 2Only normal calibration is required. Similarly, the first sensor 11 is also calibrated according to the normal calibration method. When the first sensor 11 and the second sensor 12 simultaneously capture the reticle mark pattern and the wafer mark pattern, it will be different from the one-to-one correspondence in Embodiment 1. When calibrating with the third sensor 2, the mark interval in the reticle used for calibration is 4 times that in the wafer. At this time, the intervals of the mark patterns collected by the first sensor 11 and the second sensor 12 in the reticle and the wafer are equal. Therefore, the horizontal offset (Δx, Δy) in the wafer coordinate system is required. After being corrected by the second-order parameters, the offset value of the corresponding point on the reticle is obtained, and then the pose transformation R 12 and T 12 between the first sensor 11 and the second sensor 12 is calibrated with this offset value.

[0086] In one embodiment, a calibration method is proposed for calibrating the reticle and the substrate in the step lithography process. Based on the pose determination method of the above embodiment, the calibration method includes the following steps:

[0087] S201: Calibrate the horizontal sensor 1 based on the relative pose;

[0088] S202: During the step lithography process of the step lithography apparatus, calibrate the relative position relationship between the reticle and the substrate based on the calibrated horizontal sensor 1.

[0089] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for determining the pose of a horizontal sensor, characterized in that, the horizontal sensor includes a first sensor and a second sensor that are fixedly arranged facing away from each other, and are used for measuring the motion parameters between the mask and the substrate of the step exposure device; the pose determination method includes the following steps: S101: Configure a reference mask and a reference substrate; a calibration mask pattern is set on the reference mask, and a calibration exposure pattern is set on the reference substrate; the calibration exposure pattern is used to display the exposure position state of calibrating at least a part of the calibration mask pattern under an ideal environment; S102: Install the reference mask and the reference substrate on the mask installation position and the substrate installation position respectively; S103: Set a third sensor that can penetrate the reference mask to sense the calibration exposure pattern and can sense the calibration mask pattern; from the side of the reference mask away from the reference substrate, measure the calibration mask pattern and the calibration exposure pattern through the third sensor, and obtain the reference relative position relationship between at least one selection point of the mask pattern and the calibration exposure pattern corresponding to the selection point; S104: Based on the first sensor and the second sensor, measure the calibration mask pattern and the calibration exposure pattern, and obtain the offset relative position relationship between the selection point and the corresponding point of the selection point on the calibration exposure pattern; based on the reference relative position relationship and the offset relative position relationship, calculate the relative pose between the first sensor and the second sensor.

2. The method for determining the pose of a horizontal sensor according to claim 1, characterized in that, the first sensor, the second sensor and the third sensor are all vision devices; the reference mask is a transparent mask.

3. The method for determining the pose of a horizontal sensor according to claim 1, characterized in that, the third sensor is a double telecentric lens.

4. The method for determining the pose of a horizontal sensor according to claim 3, characterized in that, when the scaling factor between the calibration exposure pattern and the calibration mask pattern is 1, the method for obtaining the reference relative position relationship is: Based on the third sensor, measure the horizontal pixel offset between the corresponding point and the selection point; Obtain the reference relative position relationship.

5. The method for determining the pose of a horizontal sensor according to claim 3, characterized in that, when the scaling factor between the calibration exposure pattern and the calibration mask pattern is not 1, the method for obtaining the reference relative position relationship is: Based on the third sensor, measure the horizontal pixel offset between the corresponding point and the selection point; Substitute the magnification ratio between the calibration exposure pattern and the calibration mask pattern into the horizontal pixel offset to obtain the reference relative position relationship.

6. The method for determining the pose of a horizontal sensor according to claim 3, characterized in that, when a lens or a lens group with a magnification ratio not equal to 1 is arranged between the reference mask and the reference substrate; the method for obtaining the reference relative position relationship is: Measure the horizontal pixel offset between the corresponding point and the selected point based on the third sensor; Substitute the internal parameters of the third sensor and the distortion parameters of the lens or lens group into the pixel offset; Obtain the reference relative position relationship.

7. The method for determining the pose of the horizontal sensor according to any one of claims 1-5, characterized in that, the calculation method of the relative pose is: Set the reference offset as (Δx, Δy); take a fixed point P in the world coordinate system, and set its coordinates as P w (x, y, z); the field-of-view parameters of the first sensor and the second sensor include internal parameters and external parameters; the internal parameters include the fundamental matrix radial distortion (k 1 , k 2 , k 3 ) and tangential distortion (p 1 , p 2 ); the external parameter is the relative pose, which is described by the rotation matrix and the translation vector T = (t 1 , t 2 , t 3 ); let (x, y) be the physical coordinates of the image plane, then: T ​ Let the world coordinate system at the selected point be P 1 (X, Y 1 , Z 1 ), and the world coordinate system of the corresponding point be P 2 (X 2 , Y 2 , Z 2 ). Project P 1 and P 2 onto the coordinate systems of the first sensor and the second sensor respectively: Let the pose transformation from the first sensor to the second sensor be R 12 and T 12 , and the coordinate system under the first sensor is converted to the coordinate system under the second sensor as follows: Solve for P in the coordinate system of the first sensor 1 and P 2 The horizontal pixel offset (Δx 2 , Δy 2 ) between points; that is: Based on the size of the image of the calibration exposure pattern, calculate the actual size corresponding to each pixel on the second sensor. Let the scaling coefficient be s, then:

8. The method for determining the pose of the horizontal sensor according to claim 7, characterized in that, The said R 12 and T 12 are obtained based on no less than 6 sets of corresponding selected points - corresponding points.

9. A calibration method for calibrating a mask and a substrate during a step lithography process, based on the pose determination method according to any one of claims 1-8, characterized in that, the calibration method includes the following steps: S201: Calibrate the horizontal sensor based on the relative pose; S202: During the step lithography process of the step lithography apparatus, calibrate the relative position relationship between the mask and the substrate based on the calibrated horizontal sensor.

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