Alignment leveling system, alignment leveling method, and lithographic apparatus

Abstract

The application discloses an alignment and leveling system, an alignment and leveling method and a photoetching device, and belongs to the technical field of semiconductor devices. The alignment and leveling system comprises a pre-alignment unit at a pre-alignment position, which performs pre-alignment of a substrate; a coarse alignment and coarse leveling unit at a wafer loading position, which performs coarse alignment and coarse leveling of the substrate respectively, wherein a first leveling module is closer to the substrate than a first alignment module; a fine alignment unit at a fine alignment position, which performs vertical height compensation and fine alignment of the substrate; and a fine leveling unit at an exposure position, which performs fine leveling of the substrate. By configuring functionally independent processing units at different stations in sequence, a step-by-step and progressive alignment and leveling system is formed, the alignment and leveling tasks are decomposed and executed step by step in each process, all compensation operations are avoided from being concentrated at the final exposure position, the process time is effectively shortened under the premise of ensuring high alignment and leveling precision, and the fundamental purpose of improving photoetching yield is achieved.

Description

Technical Field

[0001] This application relates to the field of semiconductor equipment technology, and in particular to an alignment and leveling system, an alignment and leveling method, and a photolithography apparatus. Background Technology

[0002] In photolithography, alignment and leveling are crucial for ensuring the accuracy of pattern overlay. However, this process typically involves multiple measurements and pose adjustments, resulting in significant time consumption and becoming one of the bottlenecks restricting the productivity of photolithography equipment. As semiconductor manufacturing moves towards higher precision and capacity, how to effectively shorten the time required for alignment and leveling while maintaining nanometer-level accuracy has become a pressing technical challenge for the industry. Therefore, there is an urgent need for an alignment and leveling method and system that can significantly improve productivity while ensuring photolithography accuracy. Summary of the Invention

[0003] This application provides an alignment and leveling system, an alignment and leveling method, and a lithography apparatus. By sequentially configuring functionally independent processing units at different workstations, a step-by-step, progressive alignment and leveling system is constructed. In this system, alignment and leveling tasks are decomposed and distributed across various processes, avoiding the concentration of all compensation operations at the final exposure position. This shortens process time while ensuring high alignment and leveling accuracy, ultimately achieving the fundamental goal of improving lithography yield.

[0004] To achieve the above objectives, according to a first aspect of this application, an alignment and leveling system is provided, comprising:

[0005] A pre-alignment unit, set at a pre-alignment position, includes a vision module. The vision module acquires the contour information and orientation feature information of the substrate for pre-aligning the substrate.

[0006] A coarse alignment and coarse leveling unit is set at the upper film position and includes a first alignment module and a first leveling module. The first alignment module obtains a first horizontal compensation value of the substrate and performs coarse alignment of the substrate according to the first horizontal compensation value. The first leveling module obtains a first vertical compensation value of the substrate and performs coarse leveling of the substrate according to the first vertical compensation value. The first leveling module is closer to the substrate than the first alignment module.

[0007] The precision alignment unit is set at the precision alignment position and includes a second alignment module and a focusing module. The focusing module obtains a second vertical compensation value of the substrate and adjusts the vertical height of the substrate according to the second vertical compensation value. The second alignment module obtains a second horizontal compensation value of the substrate and performs precision alignment on the substrate according to the second horizontal compensation value.

[0008] The fine-tuning unit is located at the exposure position and includes a second leveling module. The second leveling module acquires a third vertical compensation value of the substrate and performs fine-tuning of the substrate based on the third vertical compensation value.

[0009] According to a second aspect of this application, an alignment and leveling method is also provided, applied to the alignment and leveling system described in the above technical solution, the alignment and leveling method comprising:

[0010] In the pre-alignment step, at the pre-alignment position, the vision module is activated to acquire the contour information and orientation feature information of the substrate, and the substrate is pre-aligned.

[0011] In the coarse alignment and coarse leveling step, at the loading position, the first alignment module and the first leveling module are started simultaneously, and during the movement of the motion stage towards the fine alignment position, the substrate is coarsely aligned and coarsely leveled according to the first horizontal compensation value and the first vertical compensation value respectively.

[0012] In the fine alignment step, at the fine alignment position, the second alignment module and the focusing module are started simultaneously. During the operation of the second alignment module, the vertical height of the substrate is compensated in real time based on the second vertical compensation value obtained by the focusing module. And during the movement of the stage towards the exposure position, the substrate is finely aligned according to the second horizontal compensation value.

[0013] In the fine-tuning step, at the exposure position, the second leveling module is activated to obtain the third vertical compensation value of the substrate and perform fine-tuning of the substrate.

[0014] According to a third aspect of this application, a photolithography apparatus is also provided, comprising: an alignment and leveling system as described in the above technical solution, or an alignment and leveling method as described in the above technical solution.

[0015] The alignment and leveling system in this application embodiment, through the above technical solution, has at least the following beneficial effects: This application constructs a step-by-step, progressive alignment and leveling system by sequentially configuring functionally independent processing units (pre-alignment unit, coarse alignment and coarse leveling unit, fine alignment unit, and fine leveling unit) at different workstations (pre-alignment station, loading station, fine alignment station, and exposure station). In this system, the alignment and leveling tasks are decomposed into steps for execution in each process, avoiding the situation where all compensation operations are concentrated at the final exposure station, thus systematically improving the overall alignment and leveling accuracy and lithography yield. Specifically, the pre-alignment unit eliminates initial transmission errors, the fine alignment unit corrects the overall horizontal pose, and the fine leveling unit finally eliminates vertical residual deviations. This step-by-step refinement process helps to ensure the final lithography accuracy. Furthermore, by additionally setting up a wafer loading position and a corresponding coarse alignment and leveling unit between the pre-alignment and fine alignment positions, residual deviations from previous processes can be compensated. More importantly, the substrate can be pre-positioned within the field of view of the fine alignment unit, avoiding the problem of excessively long mark search time caused by the small field of view of the fine alignment unit, thereby improving production line cycle time. In summary, this solution starts from the core requirements of alignment and leveling, and through optimized process flow design, effectively shortens process time while ensuring high alignment and leveling accuracy, ultimately achieving the fundamental goal of improving lithography yield.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0019] Figure 1 This is one of the overall structural schematic diagrams of the alignment and leveling system provided in the embodiments of this disclosure;

[0020] Figure 2 This is one of the structural schematic diagrams of the coarse alignment and coarse leveling unit provided in the embodiments of this disclosure;

[0021] Figure 3 This is the second schematic diagram of the coarse alignment and coarse leveling unit provided in the embodiments of this disclosure;

[0022] Figure 4This is one of the schematic diagrams of the operation of the coarse alignment and coarse leveling unit provided in the embodiments of this disclosure;

[0023] Figure 5 This is the second schematic diagram of the operation of the coarse alignment and coarse leveling unit provided in the embodiments of this disclosure;

[0024] Figure 6 This is the second schematic diagram of the overall structure of the alignment and leveling system provided in this embodiment of the disclosure;

[0025] Figure 7 This is an overall flowchart of the alignment and leveling method provided in the embodiments of this disclosure;

[0026] Figure 8 This is a flowchart of the coarse alignment and coarse leveling steps in the alignment and leveling method provided in this embodiment of the disclosure;

[0027] Figure 9 This is a flowchart of the fine alignment step in the alignment and leveling method provided in this embodiment;

[0028] Figure 10 This is a flowchart of the fine-tuning step in the alignment and leveling method provided in this embodiment.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1- Alignment and leveling system;

[0031] 2-Pre-alignment unit; 21-Vision module; 22-Turntable;

[0032] 3- Coarse alignment and leveling unit; 31- First alignment module; 311- Fixing frame; 312- First drive mechanism; 313- Second drive mechanism; 314- First vision mechanism; 315- Second vision mechanism; 32- First leveling module; 321- First ranging sensor; 322- Second ranging sensor; 323- Third ranging sensor; 324- Support rod; 325- First detection point; 326- Second detection point; 327- Third detection point;

[0033] 4-Precision alignment unit; 41-Second alignment module; 411-Third vision mechanism; 412-First light source; 413-First lens group; 42-Focusing module; 421-Fourth vision mechanism; 422-Beam splitter prism; 423-Second lens group; 424-Second light source; 425-Third lens group;

[0034] 5-Fine-tuning unit; 51-Second leveling module; 511-Fifth vision mechanism; 512-Sixth vision mechanism;

[0035] 6-Substrate; 61-First alignment mark; 62-Second alignment mark;

[0036] 7-Motion stage; 8-Objective lens; 81-Objective lens support frame;

[0037] A - Pre-alignment position; B - Film loading position; C - Fine alignment position; D - Exposure position. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship according to the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] 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 technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] This application provides an alignment and leveling system, an alignment and leveling method, and a photolithography apparatus, which are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, in the following embodiments, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0043] Please see Figure 1 and Figure 2The alignment and leveling system 1 of this application includes a pre-alignment unit 2, a coarse alignment and coarse leveling unit 3, a fine alignment unit 4, and a fine leveling unit 5.

[0044] The pre-alignment unit 2 is located at the pre-alignment position A and includes a vision module 21 and a turntable 22. The turntable 22 carries the substrate 6. The vision module 21 acquires the contour information and orientation feature information of the substrate 6. The turntable 22 drives the substrate 6 to rotate based on the contour information and orientation feature information acquired by the vision module 21 in order to pre-align the substrate 6.

[0045] The coarse alignment and coarse leveling unit 3 is disposed at the upper substrate position B and includes a first alignment module 31 and a first leveling module 32. The first alignment module 31 acquires a first horizontal compensation value of the substrate 6 and performs coarse alignment of the substrate 6 according to the first horizontal compensation value. The first leveling module 32 acquires a first vertical compensation value of the substrate 6 and performs coarse leveling of the substrate 6 according to the first vertical compensation value. The first leveling module 32 is closer to the substrate 6 than the first alignment module 31.

[0046] The precision alignment unit 4 is disposed at the precision alignment position C and includes a second alignment module 41 and a focusing module 42. The focusing module 42 acquires a second vertical compensation value of the substrate 6 and adjusts the vertical height of the substrate 6 according to the second vertical compensation value. The second alignment module 41 acquires a second horizontal compensation value of the substrate 6 and performs precision alignment of the substrate 6 according to the second horizontal compensation value.

[0047] The fine-tuning unit 5 is located at the exposure position D and includes a second leveling module 51. The second leveling module 51 acquires the third vertical compensation value of the substrate 6 and performs fine-tuning of the substrate 6 based on the third vertical compensation value.

[0048] In this technical solution, the substrate 6 is first transported by an external transfer system to the pre-alignment position A corresponding to the pre-alignment unit 2. Then, the turntable 22 carries the substrate 6 and fixes it by adsorption. The vision module 21, located above the turntable 22, dynamically identifies and samples the edge contour of the rotating substrate 6 to obtain its contour information. Based on this contour information, it calculates the positional deviation between the instantaneous geometric center of the substrate 6 and the rotation center of the turntable 22. Based on this deviation data, the turntable 22 is driven to perform pose compensation, aligning the geometric center of the substrate 6 with the rotation center of the turntable 22, thus completing the centering operation. Simultaneously, the vision module 21 identifies the orientation features of the substrate 6, such as flat edges or notches, obtains its orientation feature information, and calculates the angular orientation of these features. Based on this angular orientation, the turntable 22 is driven to rotate again, correcting the substrate 6 to the preset angle required for subsequent processes. The pre-alignment unit 2 compensates for the initial pose error generated during the external transfer of the substrate 6, providing a reference guarantee for the accurate positioning of the substrate 6 in subsequent workstations. It is understood that the term "substrate" in this solution refers to any applicable sheet-like process object, including but not limited to silicon wafers, glass substrates, or compound semiconductor substrates. The term "adsorption" refers to any method of mounting the sheet that can achieve a fixing function, including vacuum adsorption or electrostatic adsorption.

[0049] The coarse alignment and coarse leveling unit 3 is positioned above the upper wafer position B. The first alignment module 31 acquires a first horizontal compensation value for the substrate 6, which includes compensation components for the substrate 6 in the X, Y, and Rz directions. The first leveling module 32 acquires a first vertical compensation value for the substrate 6, which includes compensation components for the substrate 6 in the Z, Rx, and Ry directions. Since the detection range of the first leveling module 32 is smaller than that of the first alignment module 31, the first leveling module 32 is spatially positioned closer to the substrate 6. This ensures that the two modules can work synchronously and without interference at the upper wafer position B, enabling parallel measurement of the horizontal and vertical pose deviations of the substrate 6. This improves detection efficiency, shortens production cycle time, and increases lithography yield. By using the coarse alignment and coarse leveling unit 3, on the one hand, it can further compensate for the residual pose deviation of the substrate 6 after pre-alignment; on the other hand, it can initially position the substrate 6 within the field of view of the subsequent fine alignment unit 4, thereby avoiding the situation where the search mark time is too long due to the small field of view of the fine alignment unit 4, which helps to improve alignment efficiency and thus improve lithography yield.

[0050] The fine alignment unit 4 is positioned above the fine alignment position C. During operation, the second alignment module 41 and the focusing module 42 work together. Specifically, the focusing module 42 detects and acquires the second vertical compensation value of the substrate 6 in the Z direction in real time to maintain focusing accuracy; simultaneously, the second alignment module 41 acquires the second horizontal compensation value of the substrate 6, which includes compensation components of the substrate 6 in the X, Y, and Rz directions. In the fine alignment unit 4, the focusing module 42 provides a stable focal plane reference for the alignment measurement of the second alignment module 41, ensuring the imaging and measurement accuracy of the second alignment module 41; based on this, the second alignment module 41 accurately measures the overall horizontal pose deviation of the substrate 6 and performs pose correction based on the measurement results, thereby ensuring that the substrate 6 is transferred to the exposure position with extremely high positioning and orientation accuracy, providing a guarantee for the accuracy of subsequent photolithography processes.

[0051] The fine-tuning unit 5 is positioned above the exposure position D. As the final pose assurance step before exposure, the second leveling module 51 accurately detects the vertical pose of the area to be exposed in the substrate 6, obtaining a third vertical compensation value for the substrate 6 in the Z, Rx, and Ry directions. The fine-tuning unit 5 then fine-tunes the local tilt and height of the substrate 6, ensuring that the surface of the area to be exposed on the substrate 6 is within the reference focal plane of the objective lens 8 at the moment of exposure, eliminating residual vertical errors from previous steps, and ensuring the transfer accuracy of the final lithographic pattern.

[0052] Therefore, this application adopts the above design, constructing a step-by-step, progressive alignment and leveling system by sequentially configuring functionally independent processing units (pre-alignment unit 2, coarse alignment and coarse leveling unit 3, fine alignment unit 4, and fine leveling unit 5) at different workstations (pre-alignment station A, loading station B, fine alignment station C, and exposure station D). In this system, the alignment and leveling tasks are decomposed and executed step by step in each process, avoiding the situation where all compensation operations are concentrated at the final exposure station, thus balancing lithography yield and overall alignment and leveling accuracy. Specifically, pre-alignment unit 2 eliminates initial transmission errors, fine alignment unit 4 corrects the overall horizontal pose, and fine leveling unit 5 finally eliminates vertical residual deviations. This step-by-step refinement process helps ensure the final lithography accuracy. Meanwhile, an additional wafer mounting position B and a corresponding coarse alignment and leveling unit 3 are set between the pre-alignment position A and the fine alignment position C. This can compensate for residual deviations in the previous process. More importantly, it can pre-position the alignment marks on the substrate 6 within the field of view of the fine alignment unit 4, effectively avoiding the problem of excessively long alignment mark search time caused by the small field of view of the fine alignment unit 4, thereby improving the production line cycle time. In other words, this solution starts from the core requirements of alignment and leveling, and through optimizing the process flow design, shortens the process time while ensuring high alignment and leveling accuracy, ultimately achieving the fundamental goal of improving lithography yield.

[0053] Please see Figure 2 and Figure 3 The first alignment module 31 in the coarse alignment and coarse leveling unit 3 includes: a fixed frame 311, a first drive mechanism 312, a second drive mechanism 313, a first vision mechanism 314, and a second vision mechanism 315. The first drive mechanism 312 and the second drive mechanism 313 are both mounted on the fixed frame 311 and can move towards or away from each other along the fixed frame 311. The first vision mechanism 314 and the second vision mechanism 315 are fixedly connected to the first drive mechanism 312 and the second drive mechanism 313, respectively, and are driven by the first drive mechanism 312 and the second drive mechanism 313, respectively. The first vision mechanism 314 and the second vision mechanism 315 are set at the same height relative to the motion stage 7 (i.e., the distance between the object surface of the first vision mechanism 314 and the surface of the motion stage 7 (or the substrate 6) is consistent with the distance between the object surface of the second vision mechanism 315 and the surface of the motion stage 7 (or the substrate 6), thereby ensuring that the two vision mechanisms can synchronously acquire alignment mark information on the substrate 6).

[0054] In this technical solution, the first vision mechanism 314 and the second vision mechanism 315 can move relative to each other under the drive of their respective driving mechanisms (first driving mechanism 312 and second driving mechanism 313). On the one hand, this allows for flexible positioning and acquisition of alignment mark information distributed at different positions (different fields) on the substrate 6, ensuring measurement integrity; on the other hand, please refer to... Figure 4 and Figure 5 By adjusting the relative distance between the two vision mechanisms, the coarse alignment and coarse leveling unit 3 can adaptively match substrates 6 of different sizes, thereby improving the versatility and compatibility of the equipment.

[0055] It is understood that both the first vision mechanism 314 and the second vision mechanism 315 are vision components with image acquisition capabilities, such as cameras. Furthermore, the drive control of the first vision mechanism 314 and the second vision mechanism 315 is an optional configuration. In practical applications, they can be driven synchronously or independently to meet different working conditions and cycle time requirements. In addition, the performance parameters of the first vision mechanism 314 and the second vision mechanism 315 can be configured to be identical or different as needed to adapt to different detection tasks and accuracy requirements.

[0056] Please see Figure 2 and Figure 3 The first vision mechanism 314 and the second vision mechanism 315 are arranged symmetrically about the center O of the substrate 6.

[0057] In this technical solution, the first vision mechanism 314 and the second vision mechanism 315 are configured as a structure that is centrally symmetrically distributed with the center O of the substrate 6 as the center of symmetry. With the help of this symmetrical structure, the two vision mechanisms can simultaneously acquire alignment mark information in two relatively far apart and centrally symmetrical regions (within the field) on the substrate 6, avoiding the problem of being unable to effectively characterize the macroscopic pose of the entire substrate 6 due to measurement points being too close. Simultaneously, by jointly solving the coordinate data of a set of alignment marks in the symmetrical field, a good averaging and offsetting effect can be achieved on random or systematic errors introduced by factors such as local deformation and thermal expansion of the substrate 6. Therefore, this symmetrical structure about the center O of the substrate 6 not only ensures the representativeness of the measurement points for the global pose of the substrate 6, but also improves the global accuracy and robustness of the alignment calculation from the perspective of data processing principles.

[0058] Please see Figure 2 and Figure 3 The first leveling module 32 in the coarse alignment and coarse leveling unit 3 includes a first ranging sensor 321, a second ranging sensor 322, and a third ranging sensor 323. Each ranging sensor is fixed to the mounting frame 311 by a support rod 324. The first ranging sensor 321, the second ranging sensor 322, and the third ranging sensor 323 are arranged in a triangle on the edge of the substrate 6, and all three are set at the same height relative to the motion stage 7 (i.e., the distance between the detection surface of each ranging sensor and the surface of the motion stage 7 (or the substrate 6) is consistent, thereby ensuring that each ranging sensor can synchronously acquire height information on the substrate 6).

[0059] In this technical solution, three ranging sensors distributed in a triangle on the edge area of ​​the substrate 6 simultaneously collect the height information of three points on it, which can ensure that the measurement data is fully dispersed in space, thereby comprehensively characterizing the overall vertical pose of the substrate 6 and improving the accuracy and reliability of leveling measurement.

[0060] It is understood that the first ranging sensor 321, the second ranging sensor 322, and the third ranging sensor 323 can be selected from components with surface tilt measurement functions, such as spectral confocal sensors. Furthermore, each ranging sensor can be configured with an independent drive mechanism according to actual detection needs, enabling flexible adjustment of the measurement position. In addition, the performance parameters of each ranging sensor can be configured uniformly or differentiated to adapt to different detection tasks and accuracy levels.

[0061] Please see Figure 2 and Figure 3 The first ranging sensor 321, the second ranging sensor 322, and the third ranging sensor 323 are arranged in an isosceles triangle or an equilateral triangle.

[0062] In this technical solution, configuring the three ranging sensors in an equilateral triangle distribution provides an optimal isotropic measurement reference, ensuring that the three detection points have equal representational effects on the overall plane of the substrate 6, thereby giving the measurement results high stability and anti-interference capability. Configuring the three ranging sensors in an isosceles triangle distribution concentrates higher measurement sensitivity in a specific direction, making it suitable for working conditions with higher control requirements for tilt along a specific axis.

[0063] Please see Figure 1 and Figure 6 In the fine alignment unit 4, the second alignment module 41 includes a third vision mechanism 411, and the focusing module 42 includes a fourth vision mechanism 421. The third vision mechanism 411 and the fourth vision mechanism 421 are connected, and they share the same imaging optical path through the beam splitter 422. The second vertical compensation value is the distance between the surface of the substrate 6 and the reference focal plane of the third vision mechanism 411, obtained by the fourth vision mechanism 421.

[0064] In this technical solution, to ensure the imaging and measurement accuracy of the second alignment module 41, a focusing module 42 is specifically set up to share a portion of the optical path with it. When the second alignment module 41 images the alignment mark on the substrate 6, the focusing module 42 can synchronously detect the defocus state of the same mark by means of the shared optical path, thereby acquiring and compensating for the positional deviation of the substrate 6 relative to the reference focal plane of the second alignment module 41 in real time. Specifically, the third vision mechanism 411 includes a first light source 412, a first lens group 413, a beam splitter 422, and a second lens group 423 arranged sequentially along the optical path. The image sensor located at the rear end is omitted in the figure. The fourth vision mechanism 421 includes a second light source 424, a third lens group 425, a beam splitter 422, and a second lens group 423 arranged sequentially along the optical path. The image sensor located at the rear end is omitted in the figure. Among them, the beam splitter 422 and the second lens group 423 together constitute the shared optical path portion of the third vision mechanism 411 and the fourth vision mechanism 421. The Z-direction distance value of the substrate 6 relative to the reference focal plane of the third vision mechanism 411, measured in real time by the fourth vision mechanism 421, is used as the second vertical compensation value, and the vertical height of the substrate 6 is compensated in real time using this value. It can be understood that the reference focal plane of the third vision mechanism 411 refers to the axial position range within which its optical system can form a clear image of the alignment marks on the surface of the substrate 6.

[0065] While ensuring the second alignment module 41 is in a clear imaging state, its third vision mechanism 411 acquires the coordinate information of multiple alignment marks located at different positions (different fields) on the substrate 6. Based on this coordinate data, an algorithm calculates the second horizontal compensation value of the substrate 6, which includes compensation components of the substrate 6 in the X, Y, and Rz directions, and then performs pose correction. The fine alignment unit 4 ensures that the substrate 6 has extremely high positioning and orientation accuracy when it is transferred to the exposure position, thus laying the foundation for the pattern overlay accuracy of subsequent photolithography processes.

[0066] Please see Figure 1 and Figure 6 In the fine-tuning unit 5, the second leveling module 51 includes a fifth vision mechanism 511 and a sixth vision mechanism 512. The fifth vision mechanism 511, the sixth vision mechanism 512, and the objective lens are all supported by an objective lens support frame 81. The fifth vision mechanism 511 and the sixth vision mechanism 512 are fixed to both sides of the objective lens 8, and are set at the same height relative to the motion stage 7 (i.e., the distance between the object surface of the fifth vision mechanism 511 and the surface of the motion stage 7 (or the substrate 6) is consistent with the distance between the object surface of the sixth vision mechanism 512 and the surface of the motion stage 7 (or the substrate 6), thereby ensuring that the two vision mechanisms can work together). The fifth vision mechanism 511 projects a measurement beam onto the surface of the substrate 6 at a predetermined angle, and the sixth vision mechanism 512 receives the reflected light from the measurement beam and detects changes in the position of the light spot. The third vertical compensation value is the distance of the substrate 6 relative to the reference focal plane of the objective lens 8, obtained by the fifth vision mechanism 511 and the sixth vision mechanism 512 based on the changes in the position of the light spot.

[0067] In this technical solution, through the synergistic action of the fifth vision mechanism 511 and the sixth vision mechanism 512, the vertical pose of the area to be exposed in the substrate 6 is accurately detected. Compensation components of the substrate 6 in the Z, Rx, and Ry directions are obtained as the third vertical compensation value. Furthermore, closed-loop compensation with nanometer-level precision is performed on the local tilt and height of the area to be exposed in the substrate 6, ensuring that the exposed area is within the reference focal plane range of the objective lens 8 at the moment of exposure. This fine-tuning step, as the final link in the pose control chain, eliminates residual vertical errors from previous steps, ensuring the transfer accuracy of the final lithographic pattern. It can be understood that the reference focal plane of the objective lens 8 refers to the axial working range within which its optical system, within the depth of field, enables the surface of the substrate 6 to form a clear image on the image plane that meets the resolution requirements.

[0068] Please see Figure 7 In some embodiments of this application, this application also provides an alignment and leveling method, which is applied to the alignment and leveling system described in any of the above technical solutions. The alignment and leveling method includes: a pre-alignment step, a coarse alignment and coarse leveling step, a fine alignment step, and a fine leveling step.

[0069] In the pre-alignment step, at the pre-alignment position, the vision module 21 is activated to acquire the contour information and orientation feature information of the substrate 6 and pre-align the substrate 6.

[0070] Specifically, the substrate 6 is first transported to pre-alignment position A by an external transmission system. At pre-alignment position A, the vision module 21 is activated to dynamically identify and sample the edge contour of the rotating substrate 6, acquiring its contour information. Based on this contour information, the positional deviation between the instantaneous geometric center of the substrate 6 and the rotation center of the turntable 22 is calculated. Based on this deviation data, the turntable 22 is driven to perform pose compensation, aligning the geometric center of the substrate 6 with the rotation center of the turntable 22, completing the centering operation. Simultaneously, the vision module 21 identifies the orientation features of the substrate 6, such as flat edges or notches, acquiring its orientation feature information and calculating the angular orientation of these features. Based on this angular orientation, the turntable 22 is driven to rotate again, correcting the substrate 6 to the preset angle required for subsequent processes. Completing the centering and orientation of the substrate 6 completes the pre-alignment of the substrate 6. This pre-alignment step compensates for the initial pose error generated during external transport, providing a reference guarantee for the accurate positioning of the substrate 6 in subsequent workstations.

[0071] Please see Figure 8 In the coarse alignment and coarse leveling step, at the upper position, the first alignment module 31 and the first leveling module 32 are started simultaneously, and during the movement of the motion stage 7 towards the fine alignment, the substrate 6 is coarsely aligned and coarsely leveled according to the first horizontal compensation value and the first vertical compensation value respectively.

[0072] Specifically, after pre-alignment, the substrate 6 is transferred to the motion stage 7 located at the wafer mounting position B. The system then simultaneously activates the first alignment module 31 and the first leveling module 32, enabling parallel operation of the two modules without interference, shortening the production cycle time, and improving lithography yield. Specifically, the first alignment module 31 photographs the coarse alignment mark 61 on the substrate 6, obtaining its coordinate position information; the first leveling module 32 collects height information from multiple points on the surface of the substrate 6, thereby simultaneously measuring the horizontal and vertical pose deviations of the substrate 6 and improving inspection efficiency. After the first alignment module 31 completes the photographing of the first alignment mark 61 and the first leveling module 32 completes the collection of height information from multiple points, the system immediately drives the motion stage 7 to the next station, the fine alignment position C. During this movement, the system processes the aforementioned photographing and acquisition results in parallel, obtaining the first horizontal compensation value and the first vertical compensation value, and simultaneously compensates for the pose of the substrate 6 based on these values. This process design avoids the time wasted waiting for data processing and compensation at the loading position B. By embedding the calculation and compensation actions into the transfer process of the motion stage 7, the production cycle can be shortened and the lithography yield can be improved.

[0073] Regarding the coarse alignment step, within the first alignment module 31, the first vision mechanism 314 and the second vision mechanism 315 simultaneously capture images of the first alignment marks 61 distributed at different positions on the substrate 6: the first vision mechanism 314 acquires the coordinates of the first alignment mark 61 at a first position on the substrate 6, as the first position information; the second vision mechanism 315 acquires the coordinates of the first alignment mark 61 at a second position on the substrate 6, as the second position information. The system then performs joint calculations based on the acquired first and second position information to finally obtain the first horizontal compensation value of the substrate 6. This compensation value includes the pose deviation components of the substrate 6 in the X, Y, and Rz directions. That is, during the coarse alignment of the substrate 6, by configuring the first vision mechanism 314 and the second vision mechanism 315, simultaneous acquisition of alignment marks at different positions on the substrate 6 is achieved. Based on the multi-point position information acquired in this single capture, the system can calculate the pose deviation of the substrate 6 in the X, Y, and Rz directions in one operation. This method avoids the process of multiple movements and shooting required by traditional single-vision mechanisms, shortens the alignment time, and thus directly helps to improve lithography yield.

[0074] Regarding the coarse leveling step, within the first leveling module 32, a first ranging sensor 321, a second ranging sensor 322, and a third ranging sensor 323, arranged in a triangular configuration, collect height information from detection points at different locations on the substrate 6. The first ranging sensor 321 collects the height information of the first detection point 325 on the substrate 6, serving as the first height information; the second ranging sensor 322 collects the height information of the second detection point 326 on the substrate 6, serving as the second height information; and the third ranging sensor 323 collects the height information of the third detection point 327 on the substrate 6, serving as the third height information. The system then performs joint calculations based on the collected height information from the three points, obtaining the pose deviations of the substrate 6 in the Z, Rx, and Ry directions in a single step, serving as the first vertical compensation value. This method, through simultaneous three-point sampling and real-time calculation, achieves efficient measurement of the vertical attitude of the substrate 6, avoiding the time consumed by traditional point-by-point acquisition and step-by-step calculation, thus shortening the leveling cycle and improving the overall lithography yield.

[0075] Please see Figure 9 In the fine alignment step, at the fine alignment position C, the second alignment module 41 and the focusing module 42 are started simultaneously. During the operation of the second alignment module 41, the vertical height of the substrate 6 is compensated in real time based on the second vertical compensation value obtained by the focusing module 42. And during the movement of the motion stage 7 towards the exposure position, the substrate 6 is finely aligned according to the second horizontal compensation value.

[0076] Specifically, the motion stage 7 moves the substrate 6 from the coarse alignment position B to the fine alignment position C for fine alignment. The second alignment module 41 images the fine alignment marks 62 at multiple different positions on the substrate 6. Simultaneously, the focusing module 42 uses the common optical path to synchronously detect the defocus state of the same mark, and obtains the Z-axis deviation value of the substrate 6 relative to the reference focal plane of the second alignment module 41 in real time as the second vertical compensation value to ensure that the image is always clear. On the basis of ensuring that the image of the second alignment module 41 is clear, the third vision mechanism 411 of the second alignment module 41 captures and collects the coordinate data of the second alignment marks 62 at multiple different positions. After the image is captured, the system immediately drives the motion stage 7 to move to the next station, namely the exposure position D. During this process, the system processes the acquired coordinate data in parallel, uses the EGA algorithm to calculate the second horizontal compensation value of the entire substrate 6 in the X, Y and Rz directions in real time, and performs pose compensation simultaneously. In this fine alignment step, on the one hand, real-time focusing and multi-marker global alignment ensure that the substrate 6 has extremely high positioning and orientation accuracy when entering the exposure position D, providing a basis for pattern registration; on the other hand, data processing and compensation operations are embedded in the transfer process of the motion stage 7 to avoid static waiting at the fine alignment position C, thereby shortening the production cycle and improving the lithography yield.

[0077] Specifically, the distance from the substrate 6 to the reference focal plane of the third vision mechanism 411, measured by the fourth vision mechanism 421 of the focusing module 42, is defined as the first distance L1, and the focal depth range within which the third vision mechanism 411 can clearly image is defined as the first threshold. If the first distance L1 is within the first threshold, it indicates that the third vision mechanism 411 is in a clear imaging state, and the second alignment mark 62 on the substrate 6 can be directly photographed using the third vision mechanism 411. If the first distance L1 exceeds the first threshold, it indicates that the third vision mechanism 411 has deviated from the clear imaging range. In this case, the Z-direction deviation value, i.e., the second vertical compensation value, needs to be obtained based on the first distance L1, and the motion stage 7 is driven to move to compensate for the pose deviation of the substrate 6 in the Z-direction until it re-enters the focal depth range of the third vision mechanism 411, ensuring clear imaging before photographing the second alignment mark 62.

[0078] also, Figure 4 The design and distribution of the first alignment mark 61 and the second alignment mark 62 are schematically illustrated. It can be understood that the specific design and arrangement of the first alignment mark 61 and the second alignment mark 62 can be designed according to actual process requirements, the core being that they can be stably identified by the first alignment module 31 and the second alignment module 41, respectively. As a preferred embodiment, the first alignment mark 61 can be in the form of a one-dimensional mark, suitable for efficient identification in the coarse alignment stage; the second alignment mark 62 can be in the form of a two-dimensional mark to meet the higher precision requirements for position and angle information in the fine alignment stage.

[0079] Please see Figure 10 In the fine-tuning step, the second leveling module 51 is activated at the exposure position to obtain the third vertical compensation value of the substrate 6 and perform fine-tuning on the substrate 6.

[0080] Specifically, the stage 7 moves the substrate 6 from the precision alignment C to the exposure position D. Once the area (field) to be exposed in the substrate 6 reaches the exposure position D, the fifth vision mechanism 511 and the sixth vision mechanism 512 in the second leveling module 51 are simultaneously activated. The fifth vision mechanism 511 projects a measurement beam onto the surface of the substrate 6 at a predetermined angle, while the sixth vision mechanism 512 receives the reflected beam and detects changes in the beam's position. Based on this change, it obtains a second distance L2 between the substrate 6 and the reference focal plane of the objective lens 8, and performs fine-tuning of the substrate 6 according to this second distance L2 to ensure precise overlap between the exposure area and the focal plane, thereby ensuring photolithography accuracy.

[0081] The system defines the distance from the substrate 6 to the reference focal plane of the objective lens 8 measured by the fifth vision mechanism 511 and the sixth vision mechanism 512 as the second distance L2, and defines the depth of focus range of the objective lens 8 as the second threshold.

[0082] If the second distance L2 is within the second threshold, it indicates that the substrate 6 is within the clear imaging range of the objective lens 8, and the exposure process can be executed immediately. If the second distance L2 exceeds the second threshold, it indicates that the substrate 6 has deviated from the clear imaging range. The system will generate a third vertical compensation value based on the second distance L2, including the pose deviations of the substrate 6 in the Z, Rx, and Ry directions, and drive the motion stage 7 to perform pose compensation, so that the substrate 6 re-enters the depth of focus range of the objective lens 8. Exposure will be started after the image is clear.

[0083] In some embodiments of this application, a photolithography apparatus is also provided, which includes an alignment and leveling system or an alignment and leveling method as described in any of the above technical solutions. Since the alignment and leveling system and method in this photolithography apparatus have the same technical features as the aforementioned alignment and leveling system and method, they can solve the same technical problems and achieve the same technical effects.

[0084] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0085] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application, and the content of this specification should not be construed as a limitation of this application.

Claims

1. An alignment and leveling system, characterized in that, include: A pre-alignment unit, located at a pre-alignment position, includes a vision module. The vision module acquires the contour information and orientation feature information of the substrate for pre-aligning the substrate. A coarse alignment and coarse leveling unit is disposed on the upper film position and includes a first alignment module and a first leveling module. The first alignment module is used to obtain a first horizontal compensation value of the substrate and perform coarse alignment of the substrate according to the first horizontal compensation value. The first leveling module is used to obtain a first vertical compensation value of the substrate and perform coarse leveling of the substrate according to the first vertical compensation value. The first leveling module is closer to the substrate than the first alignment module. A precision alignment unit, located at a precision alignment position, includes a second alignment module and a focusing module. The focusing module is used to obtain a second vertical compensation value of the substrate and adjust the vertical height of the substrate according to the second vertical compensation value. The second alignment module is used to obtain a second horizontal compensation value of the substrate and perform precision alignment on the substrate according to the second horizontal compensation value. A fine-tuning unit is located at the exposure position and includes a second leveling module. The second leveling module is used to obtain a third vertical compensation value of the substrate and to fine-tune the substrate according to the third vertical compensation value.

2. The alignment and leveling system according to claim 1, characterized in that, The pre-alignment unit also includes a turntable that supports the substrate; The turntable rotates the substrate based on the contour and orientation information acquired by the vision module, for pre-alignment of the substrate.

3. The alignment and leveling system according to claim 1, characterized in that, The first alignment module includes: Fixture; The first drive mechanism and the second drive mechanism are both mounted on the fixed frame, and the two can move towards each other or away from each other along the fixed frame; The first vision mechanism and the second vision mechanism are fixedly connected to the first driving mechanism and the second driving mechanism, respectively, and are driven by the first driving mechanism and the second driving mechanism, respectively. The first vision mechanism and the second vision mechanism are set at the same height relative to the motion table.

4. The alignment and leveling system according to claim 3, characterized in that, The first vision mechanism and the second vision mechanism are arranged in a centrally symmetrical manner with the center of the substrate as the center of symmetry.

5. The alignment and leveling system according to claim 1, characterized in that, The first leveling module includes: a first ranging sensor, a second ranging sensor, and a third ranging sensor; Each ranging sensor is fixed to the mounting frame by a support rod; The first ranging sensor, the second ranging sensor, and the third ranging sensor are arranged in a triangle and are set at the same height relative to the motion platform.

6. The alignment and leveling system according to claim 5, characterized in that, The first ranging sensor, the second ranging sensor, and the third ranging sensor are arranged in an isosceles triangle or an equilateral triangle.

7. The alignment and leveling system according to claim 1, characterized in that, The second alignment module includes a third vision mechanism, and the focusing module includes a fourth vision mechanism; The third vision mechanism and the fourth vision mechanism share the same imaging optical path through a beam splitter; The second vertical compensation value is the distance between the substrate surface and the reference focal plane of the third vision mechanism, obtained by the fourth vision mechanism.

8. The alignment and leveling system according to claim 1, characterized in that, The second leveling module includes a fifth vision mechanism and a sixth vision mechanism, which are fixed on both sides of the objective lens and set at the same height relative to the motion stage; The fifth vision mechanism projects a measurement beam onto the substrate surface at a predetermined angle, and the sixth vision mechanism receives the reflected light from the measurement beam and detects changes in the position of the light spot. The third vertical compensation value is the distance between the substrate and the reference focal plane of the objective lens, obtained by the fifth and sixth vision mechanisms based on the change in the position of the light spot.

9. A method for alignment and leveling, characterized in that, The alignment and leveling method, applied to any one of claims 1 to 8, comprises: In the pre-alignment step, at the pre-alignment position, the vision module is activated to acquire the contour information and orientation feature information of the substrate, and the substrate is pre-aligned. In the coarse alignment and coarse leveling step, at the upper position, the first alignment module and the first leveling module are started simultaneously, and during the movement of the motion stage towards the fine alignment position, the substrate is coarsely aligned and coarsely leveled according to the first horizontal compensation value and the first vertical compensation value respectively. In the fine alignment step, at the fine alignment position, the second alignment module and the focusing module are started simultaneously. During the operation of the second alignment module, the vertical height of the substrate is compensated in real time based on the second vertical compensation value obtained by the focusing module. And during the movement of the motion stage towards the exposure position, the substrate is finely aligned according to the second horizontal compensation value. In the fine-tuning step, at the exposure position, the second leveling module is activated to obtain the third vertical compensation value of the substrate and perform fine-tuning on the substrate.

10. The alignment and leveling method according to claim 9, characterized in that, In the coarse alignment and coarse leveling steps: The first alignment module is activated to capture the first alignment mark on the substrate, and the first leveling module is activated to collect the height information of multiple points on the substrate. After the shooting and data acquisition are completed, the motion stage is driven to move, and during the movement of the motion stage, the first horizontal compensation value and the first vertical compensation value are acquired to perform coarse alignment and coarse leveling of the substrate.

11. The alignment and leveling method according to claim 10, characterized in that, In the coarse alignment and coarse leveling steps: The first alignment module includes a first vision mechanism and a second vision mechanism; The first vision mechanism captures a first alignment mark at a first position on the substrate to obtain first position information; The second vision mechanism captures a first alignment mark at a second position on the substrate to obtain second position information; Based on the first location information and the second location information, the first horizontal compensation value of the substrate is obtained.

12. The alignment and leveling method according to claim 10, characterized in that, In the coarse alignment and coarse leveling steps: The first leveling module includes a first ranging sensor, a second ranging sensor, and a third ranging sensor; The first ranging sensor collects a first detection point on the substrate to obtain first height information; The second ranging sensor collects a second detection point on the substrate to obtain second height information; The third ranging sensor collects a third detection point on the substrate to obtain third height information; Based on the first height information, the second height information, and the third height information, the first vertical compensation value of the substrate is obtained.

13. The alignment and leveling method according to claim 9, characterized in that, In the fine alignment step: The second alignment module images multiple second alignment marks on the substrate through the common optical path section, and at the same time activates the focusing module to measure the first distance of the second alignment mark relative to the reference focal plane of the second alignment module in real time, and performs real-time compensation for the vertical height of the substrate. When the first distance is within the first threshold, the second alignment module performs imaging of the second alignment mark. After completing the imaging of multiple second alignment marks in sequence, it drives the motion stage to move. During the movement of the motion stage towards the exposure position, it acquires the second horizontal compensation value of the substrate and performs fine alignment of the substrate.

14. The alignment and leveling method according to claim 13, characterized in that, In the fine alignment step: The second alignment module images multiple second alignment marks at different positions on the substrate; The second alignment module includes a third vision mechanism, and the focusing module includes a fourth vision mechanism; The fourth vision mechanism acquires a first distance between the substrate and the reference focal plane of the third vision mechanism, and performs real-time compensation for the vertical height of the substrate.

15. The alignment and leveling method according to claim 9, characterized in that, In the fine-tuning step: The second leveling module includes a fifth vision mechanism and a sixth vision mechanism; The fifth vision mechanism projects a measurement beam onto the substrate surface at a predetermined angle, and the sixth vision mechanism receives the reflected light from the measurement beam and detects changes in the position of the light spot. The fifth and sixth vision mechanisms are activated simultaneously to obtain the second distance between the substrate and the reference focal plane of the objective lens based on the change in the position of the light spot. When the second distance is not within the second threshold, the third vertical compensation value of the substrate is obtained based on the second distance, and the substrate is finely leveled.

16. A photolithography apparatus, characterized in that, The photolithography equipment includes: The alignment and leveling system as described in any one of claims 1 to 8, or the alignment and leveling method as described in any one of claims 9 to 15.

Images