Method for calibrating zero plane of FLS mechanism in lithography machine device and lithography machine

Abstract

The application provides a method for calibrating a zero plane of an FLS mechanism in a photolithography machine and a photolithography machine, and relates to the technical field of photolithography machines. The method comprises the following steps: determining the positions of light spots collected by a CCD detector when a workpiece table is at different moving heights, and constructing a relationship model between the positions of the light spots and the heights of the measured surface based on the moving heights and the positions of the light spots corresponding to the moving heights; then, the position of a target light spot corresponding to the position of the optical axis center of an objective lens is substituted into the constructed relationship model, and the best focal plane height, i.e. the zero plane of the FLS mechanism, is calculated; and finally, the initial height and the target height of the FLS mechanism are used to calculate the adjustment height required by the FLS mechanism, and the FLS mechanism is controlled to move along the vertical direction based on the adjustment height, so as to complete the calibration of the zero plane.

Description

Technical Field

[0001] This application relates to the field of lithography technology, and more specifically, to a method for calibrating the zero plane of the FLS mechanism in a lithography machine and a lithography device. Background Technology

[0002] In semiconductor manufacturing, the lithography machine is the core equipment for transferring miniaturized patterns of integrated circuits. The Fine Leveling and Slanting System (FLS) is responsible for ensuring that the silicon wafer remains in the optimal focal plane and horizontal orientation throughout the exposure process. To achieve nanometer-level or even sub-nanometer-level alignment and focusing accuracy, the FLS requires a reference plane (i.e., the zero plane) as the benchmark for the entire leveling and focusing operation. This reference plane is typically determined through calibration.

[0003] Traditional reference plane calibration methods are typically manual or semi-automatic. Specifically, this may involve manual alignment using standard samples (such as mirrors or standard silicon wafers) or determining the reference plane through multiple measurements and adjustments.

[0004] However, the traditional calibration process described above is time-consuming and prone to human error, resulting in problems such as low efficiency and low accuracy. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a calibration method for the zero plane of the FLS mechanism in a lithography machine and a lithography device, so as to solve the technical problems existing in the prior art.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide a method for calibrating the zero plane of an FLS mechanism in a lithography machine and a lithography machine itself. The FLS mechanism includes: a light source, a projection slit, a projection lens group, at least one stepper motor, and an objective lens. The method includes: The position of the light spot collected by the CCD detector when the workpiece stage moves at different heights is determined; wherein, the CCD detector is mounted on the workpiece stage; Based on the aforementioned moving heights and the corresponding spot positions, a relationship model between the spot position and the height of the measured surface is determined. The target spot position corresponding to the optical axis center position of the objective lens is input into the relationship model between the spot position and the height of the measured surface to calculate the target height, which is used to characterize the optimal focal plane height. Based on the initial height and the target height of the FLS mechanism, the required adjustment height of the FLS mechanism is determined, and based on the adjustment height, the stepper motor is controlled to drive the FLS mechanism to move in the vertical direction to complete the zero plane calibration.

[0007] Optionally, the light source emitted by the projection component in the FLS mechanism is split into multiple sub-spots by a beam splitter, and the multiple sub-spots are not equidistantly distributed in the horizontal direction; Determining the position of the light spot collected by the CCD detector at different moving heights of the workpiece stage includes: At the same moving height, acquire imaging images of each of the sub-spots collected by the CCD detector; The position of the light spot at the moving height is determined based on the imaging images of each of the sub-spots.

[0008] Optionally, determining the position of the light spot at the moving height based on the imaging images of each of the sub-light spots includes: Parabolic fitting is performed on the imaging images of each of the sub-spots to generate fitting curves for each of the sub-spots; The maximum value on the fitting curve of each light spot is taken as the light spot position of each sub-light spot; The average position of each sub-spot is determined, and the average value is used as the spot position at the moving height.

[0009] Optionally, the step of determining the relationship model between the light spot position and the height of the measured surface based on each of the moving heights and the light spot positions corresponding to each moving height includes: Based on each of the stated moving heights and the corresponding light spot positions, multiple sets of measurement data are constructed. By fitting the multiple sets of measurement data, a relationship model between the position of the light spot and the height of the measured surface is obtained.

[0010] Optionally, the step of fitting the multiple sets of measurement data to obtain a relationship model between the light spot position and the height of the measured surface includes: Obtain a pre-built polynomial fitting model; Substitute the multiple sets of measurement data into the polynomial fitting model to obtain multiple polynomial fitting equations; The least squares method is used to solve the multiple polynomial fitting equations simultaneously to obtain the fitting coefficients in the polynomial fitting model. Based on the polynomial fitting model and the fitting coefficients, a relationship model between the position of the light spot and the height of the measured surface is obtained.

[0011] Optionally, the polynomial fitting model includes:

[0012] in, For the height of movement, Let A, B, C, and D be the positions of the light spot, and let A, B, C, and D be the fitting coefficients in the polynomial fitting model.

[0013] Optionally, the process of controlling the workpiece stage to move vertically includes: The workpiece stage is controlled to move multiple times in the vertical direction with the zero plane of the objective lens as a reference and according to a preset movement step size.

[0014] Optionally, determining the required adjustment height of the FLS mechanism based on its initial height and the target height includes: Determine the difference between the target height and the initial height, and use the difference as the required adjustment height for the FLS mechanism; The step of controlling the FLS mechanism to move vertically based on the adjusted height includes: If the difference is greater than zero, the FLS mechanism is controlled to move downwards in the vertical direction; If the difference is less than zero, the FLS mechanism is controlled to move upward in the vertical direction.

[0015] Secondly, this application also provides a lithography apparatus, which includes: a workpiece stage, a lithography machine main controller, a CCD detector, and an FLS mechanism; the FLS mechanism includes: a light source, a projection slit, a projection imaging lens group, and an objective lens; The photolithography equipment is used to perform the calibration method steps for the zero plane of the FLS mechanism in the photolithography equipment, so as to calibrate the zero plane of the FLS mechanism.

[0016] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a storage medium, and a bus. The storage medium stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the calibration method steps of the zero plane of the FLS mechanism in the lithography machine equipment.

[0017] The beneficial effects of this application are: This application provides a method for calibrating the zero plane of the FLS mechanism in a lithography machine and a lithography apparatus. In this application, during the vertical movement of the workpiece stage or the FLS mechanism, the position of the light spot collected by the CCD detector at different movement heights of the workpiece stage is determined. Based on the movement height and the light spot position corresponding to each movement height, a relationship model between the light spot position and the height of the measured surface is constructed. This relationship model reflects the nonlinear mapping relationship between the light spot position and the height of the measured surface. Then, the target light spot position corresponding to the optical axis center position of the objective lens is substituted into the relationship model constructed above to calculate the optimal focal plane height, i.e., the zero plane of the FLS mechanism. Using the initial height and target height of the FLS mechanism, the required adjustment height of the FLS mechanism is calculated. Based on the adjustment height, the FLS mechanism is controlled to move vertically to complete the zero plane calibration, that is, to adjust the height of the FLS mechanism to the target height of the zero plane of the FLS mechanism, so that the zero plane of the FLS projection optical path is accurately aligned with the optimal focal plane of the objective lens, thereby realizing automated zero plane calibration. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the frame of a photolithography apparatus provided in an embodiment of this application; Figure 2 A flowchart illustrating a method for calibrating the zero plane of an FLS mechanism in a lithography machine, as provided in an embodiment of this application; Figure 3 A schematic diagram of the calibration of the zero plane of an FLS mechanism is provided for an embodiment of this application; Figure 4 A flowchart illustrating another method for calibrating the zero plane of the FLS mechanism in a lithography machine provided in this application embodiment; Figure 5 A schematic diagram of the installation of the CCD detector on the workpiece stage provided in the embodiments of this application; Figure 6 A schematic diagram of the horizontal grayscale distribution of three sub-spots detected by the CCD detector provided in this embodiment of the application; Figure 7 A flowchart illustrating another method for calibrating the zero plane of the FLS mechanism in a lithography machine provided in this application embodiment; Figure 8A flowchart illustrating another method for calibrating the zero plane of the FLS mechanism in a lithography machine provided in this application embodiment; Figure 9 A flowchart illustrating another method for calibrating the zero plane of the FLS mechanism in a lithography machine provided in this application embodiment; Figure 10 This is a flowchart illustrating another method for calibrating the zero plane of the FLS mechanism in a lithography machine, provided as an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] The background technology involved in this application will be introduced.

[0024] In the lithography process, to ensure product quality, it is necessary to ensure that the silicon wafer is positioned at the optimal focal plane of the objective lens during exposure. Therefore, a focusing and leveling system (FLS) is used to measure the vertical and tilt offsets of the silicon wafer to be exposed relative to the optimal focal plane of the objective lens, and the wafer stage is used to compensate for these offsets.

[0025] The measurement reference plane of the FLS mechanism is the zero plane. The measurement data output by the FLS mechanism is the vertical and tilt offset of the measured plane relative to the zero plane. Therefore, in the early assembly and calibration stage of the photolithography equipment, the zero plane of the FLS mechanism needs to be coincided with the optimal focal plane of the objective lens so that the measurement data of the FLS mechanism can be directly output to the silicon wafer stage for focusing and leveling of the exposure field on the silicon wafer.

[0026] Due to the requirement that the null plane of the FLS mechanism and the optimal focal plane of the objective lens coincide, traditional reference plane calibration methods are usually manual or semi-automatic. Specifically, this may involve manual alignment using standard samples (such as mirrors or standard silicon wafers); or determining the reference plane through multiple measurements and adjustments.

[0027] However, the traditional calibration process described above is time-consuming and prone to human error, resulting in problems such as low efficiency and low accuracy.

[0028] To address this issue, this application proposes an automatic zero-plane calibration scheme that can quickly perform position and parameter calibration, thereby improving calibration efficiency and accuracy, reducing human error, and enhancing system stability and adaptability.

[0029] Optionally, the calibration scenario of the zero plane of the FLS mechanism in the lithography equipment provided in this application will be introduced through the following embodiments.

[0030] refer to Figure 1 The diagram shown is a schematic of the calibration scenario for the zero plane of the FLS mechanism in the lithography machine equipment provided in this application. Figure 1 As shown, the calibration scenario for the zero plane of the FLS mechanism includes: the FLS mechanism, the CCD detector, the workpiece stage, the objective lens, and the lithography machine main control unit.

[0031] The FLS mechanism includes: stepper motor 1, stepper motor 2, a light source, a projection slit, and a projection lens assembly. Stepper motor 1 and stepper motor 2 are driven synchronously to move the entire FLS mechanism up and down, so that the projection focus of the projection lens assembly of the FLS mechanism is adjusted to the optical axis center coordinate position of the objective lens null plane. For example, the light source can be a light-emitting diode.

[0032] The projection slit and projection lens assembly are used to transmit the light generated by the light source along a preset optical path to the area below the objective lens.

[0033] Before calibration begins, the objective lens is fixed in place, and the coordinates of the optimal focal plane and the center point of the optical axis of the objective lens have been measured. That is, the height of the optimal focal plane Z1 has been determined, and the center coordinate position of the objective lens Point1(X,Y) has been determined.

[0034] Optionally, the zero-plane calibration mentioned in this application only involves the calibration of the vertical height, assuming that the workpiece stage has been adjusted to be horizontal, and does not include the calibration of the tilt of the workpiece stage, that is, moving the workpiece stage or FLS mechanism in the vertical direction.

[0035] In addition to the chuck chuck for fixing the wafer on the workpiece stage, a basic marking plate FM (for alignment) and a CCD detector are also installed on one side of the workpiece stage. The CCD detector is detachable and can be removed after the FLS mechanism is calibrated.

[0036] Optionally, during the calibration process, the CCD detector is moved to a preset height and positioned directly below the optical axis of the objective lens by moving the workpiece stage or FLS mechanism in the vertical direction. Preferably, the CCD detector is arranged in the horizontal direction with its center positioned directly below the optical axis of the objective lens. For example, if the CCD detector has a total of 2048 pixels, the position of its 1024th pixel is positioned directly below the optical axis of the objective lens.

[0037] The calibration method steps for the zero plane of the FLS mechanism in the lithography machine equipment provided in the following embodiment are executed by the main control unit of the lithography machine or the processing unit in the FLS mechanism to calibrate the zero plane of the FLS mechanism, so as to ensure that the silicon wafer is located at the optimal focal plane position of the objective lens during exposure and improve product quality.

[0038] Optionally, the calibration method of the zero plane of the FLS mechanism in the lithography equipment provided in this application will be specifically explained through the following embodiments.

[0039] refer to Figure 2 The diagram shown is a flowchart illustrating a method for calibrating the zero plane of the FLS mechanism in a lithography machine according to this application. Figure 2 As shown, this method is applied to the above Figure 1 The lithography machine's main control unit or the processing unit in the FLS mechanism can be a terminal device with data processing capabilities. For example... Figure 2 As shown, the method includes: S101. Determine the position of the light spot collected by the CCD detector when the workpiece stage moves at different heights.

[0040] The CCD detector is mounted on the workpiece stage, and the upper surface of the CCD detector is parallel to the zero plane of the objective lens. That is, the upper surface of the CCD detector and the zero plane of the objective lens are two horizontal planes at different heights. The center position of the CCD detector is located at a preset position at the center of the optical axis of the objective lens, such as directly below.

[0041] In one feasible approach, the height of the FLS mechanism or the workpiece stage can be adjusted vertically during calibration. Considering that the FLS mechanism involves many components and is relatively heavy, it is preferable to move the workpiece stage up and down during calibration, while keeping the FLS mechanism stationary.

[0042] It should be noted that before calibration begins, the initial height of the FLS mechanism relative to the workpiece stage must be set. Specifically, the CCD detector is mounted on the workpiece stage, with its extension direction being the X direction (it can also be set to the Y direction; when set to the Y direction, the horizontal projection of the light from the FLS mechanism is also in the Y direction). By adjusting the X-axis and Y-axis drive mechanisms of the workpiece stage, the upper surface of the CCD detector's detection area is moved to the horizontal height of the objective lens's zero plane, preferably at the position of the objective lens's optimal focal point. However, in practice, it is sufficient to adjust it to a preset height, and this preset height is set as the initial height H0, so that the center of the CCD detector is located at the center of the objective lens's optical axis (or a preset position of the CCD detector can be moved to the position of the objective lens's center, i.e., the initial X value).

[0043] For reference Figure 3 As shown, the initial height of the workpiece stage is set to H0 (that is, the height of the upper surface of the CCD detector on the CCD detector is H0, which also corresponds to the initial height of the FLS mechanism). At this time, the position of the light spot irradiated on the CCD detector by the projection lens group is X0, and the system records a set of data (H0, X0). Then, by adjusting the Z-axis drive mechanism of the workpiece stage, the workpiece stage is driven to move upward in the vertical direction by a height ΔH, that is, the current moving height is H1. Since the workpiece stage drives the CCD detector to move only upward in the vertical direction, while the projection light path of the FLS mechanism remains stationary, the position of the light spot collected by the CCD detector will be located to the left of X0, let's assume it is X1, and a set of data (H1, X1) is recorded.

[0044] Based on the above operation, then at certain intervals of height △H, such as 10μm, move upward (or downward) from the initial predetermined height H0. At each height, two sets of data need to be measured and recorded: one is the moving height Hn of the workpiece stage and the distribution position of the light spot collected by the CCD detector along the X-axis at that moving height, i.e., the light spot position, such as Xn. At least four sets of measurement data should be obtained.

[0045] S102. Based on each movement height and the corresponding spot position, determine the relationship model between the spot position and the height of the measured surface.

[0046] S103. Input the target spot position corresponding to the optical axis center position of the objective lens into the relationship model between the spot position and the height of the measured surface, and calculate the target height.

[0047] The target height is used to characterize the optimal focal plane height, which is the zero plane of the FLS mechanism.

[0048] In one feasible approach, the same movement height and the corresponding spot position can be used as a set of measurement data, resulting in multiple sets of measurement data. These multiple sets of data are then fitted to obtain a relationship model between the spot position and the height of the measured surface. This model reflects the nonlinear mapping between the spot position and the height of the measured surface, improving the accuracy of subsequent height calculations. Then, the target spot position X corresponding to the optical axis center of the objective lens is substituted into the relationship model between the spot position and the height of the measured surface to calculate the optimal focal plane height, i.e., the zero plane of the FLS mechanism. This allows the optimal focal plane height to be derived from the constructed relationship model, avoiding residual errors caused by linear approximation.

[0049] Optionally, after the relationship model is constructed, the target height can be obtained by simply inputting the target spot position, without relying on external measurement equipment in real time, thus improving the engineering practicality of the system.

[0050] S104. Based on the initial height and target height of the FLS mechanism, determine the required adjustment height of the FLS mechanism, and based on the adjustment height, control the FLS mechanism to move in the vertical direction to complete the zero plane calibration.

[0051] The initial height of the FLS mechanism is the reference height set during initial calibration, which is usually the height of the workpiece stage during the first measurement.

[0052] Optionally, the required adjustment height, i.e., the compensation height value, of the FLS mechanism can be obtained based on the initial height and target height of the FLS mechanism. The adjustment height is then sent as a command signal to stepper motor 1 and stepper motor 2 to drive the FLS mechanism to move a distance in the vertical direction as the adjustment height. In other words, the height of the FLS mechanism is adjusted to the target height, so that the zero plane of the FLS projection light path is precisely aligned with the optimal focal plane of the objective lens. This achieves automated zero plane calibration, ensuring that the silicon wafer is located at the optimal focal plane position of the objective lens during exposure, thereby improving product quality.

[0053] Optionally, the calibration method for the zero plane of the FLS mechanism provided in this application can achieve automatic zero plane calibration without changing the optical path of the FLS mechanism. It only requires moving the workpiece stage or the overall position of the FLS mechanism up and down, reducing the probability of errors introduced by manual adjustment of the optical path.

[0054] In summary, this application provides a method for calibrating the zero plane of the FLS mechanism in a lithography machine. In this application, during the vertical movement of the workpiece stage or FLS mechanism, the position of the light spot collected by the CCD detector at different movement heights of the workpiece stage is determined. Based on the movement height and the corresponding light spot position at each movement height, a relationship model between the light spot position and the height of the measured surface is constructed. This relationship model reflects the nonlinear mapping relationship between the light spot position and the height of the measured surface. Then, the target light spot position corresponding to the optical axis center position of the objective lens is substituted into the constructed relationship model to calculate the optimal focal plane height, i.e., the zero plane of the FLS mechanism. Using the initial height and target height of the FLS mechanism, the required adjustment height of the FLS mechanism is calculated. Based on the adjustment height, the FLS mechanism is controlled to move vertically to complete the zero plane calibration, that is, adjusting the height of the FLS mechanism to the target height where the zero plane of the FLS mechanism is located, so that the zero plane of the FLS projection path is accurately aligned with the optimal focal plane of the objective lens, achieving automated zero plane calibration. This ensures that the silicon wafer is located at the optimal focal plane position of the objective lens during exposure, thereby improving product quality.

[0055] Optionally, the light source emitted by the projection component in the FLS mechanism is split into multiple sub-spots by a beam splitter, and the multiple sub-spots are not equidistantly distributed in the horizontal direction.

[0056] refer to Figure 4 As shown, step S101 above includes: S401. At the same moving height, acquire the imaging images of each sub-spot collected by the CCD detector.

[0057] S402. Determine the position of the light spot at the moving height based on the imaging images of each sub-spot.

[0058] For example, such as Figure 5 As shown, the light source is split into three sub-spots by a beam splitter. These three sub-spots are projected onto a CCD detector, which detects the three sub-spots (for ease of display). Figure 5 The grayscale distribution in the X-direction of the three black areas (representing three sub-spots) is as follows: Figure 6 As shown, Figure 6 The horizontal axis represents the number of pixels, which totals 2048. The vertical axis represents the grayscale value.

[0059] In this embodiment, the position of the light spot at the moving height can be calculated based on the imaging images of each sub-spot acquired by the CCD detector. Using three sub-spots to calculate the position effectively reduces noise, improves accuracy, enhances stability, and corrects for light spot asymmetry.

[0060] Optionally, refer to Figure 7As shown, step S402 above includes: S701. Perform parabolic fitting on the imaging images of each sub-spot to generate the fitting curve for each sub-spot.

[0061] S702. Take the maximum value on the fitted curve of each spot as the spot position of each sub-spot.

[0062] S703. Determine the average position of each sub-spot and use the average as the spot position at the moving height.

[0063] In one feasible approach, a parabola is used to fit the imaging images of the three sub-spots to obtain the fitting curves of the three sub-spots. The maximum value on the fitting curve of each spot is taken as the spot position of the corresponding sub-spot. Then, the mean value of the spot position of each sub-spot is determined and the mean value is taken as the spot position X under that value. In other words, the fitting values ​​of the three sub-spots are taken as the spot position X under the moving height.

[0064] Optionally, refer to Figure 8 As shown, step S102 above includes: S801. Based on each movement height and the corresponding spot position, construct multiple sets of measurement data.

[0065] Among them, the initial height H0 of the workpiece stage and the spot position X0 corresponding to the initial height H0 can be used as a set of measurement data (H0, X0).

[0066] S802. Fit multiple sets of measurement data to obtain a model showing the relationship between the position of the light spot and the height of the measured surface.

[0067] In one feasible approach, to ensure the accuracy of the obtained relational model, it is proposed to acquire multiple movement heights and the corresponding spot positions for each movement height, and to use the same movement height and the corresponding spot position as a set of measurement data, i.e., to construct multiple sets of measurement data, and to perform fitting processing on the multiple sets of measurement data to calculate the relational model between the spot position and the height of the measured surface.

[0068] Optionally, refer to Figure 9 As shown, step S802 above includes: S901. Obtain the pre-built polynomial fitting model.

[0069] S902. Substitute multiple sets of measurement data into the polynomial fitting model to obtain multiple polynomial fitting equations.

[0070] S903. Use the least squares method to solve multiple polynomial fitting equations simultaneously to obtain the fitting coefficients in the polynomial fitting model.

[0071] S904. Based on the polynomial fitting model and fitting coefficients, the relationship model between the position of the light spot and the height of the measured surface is obtained.

[0072] In one feasible approach, after selecting a polynomial fitting model, each set of measurement data can be substituted into the polynomial fitting model to obtain multiple polynomial fitting equations. The least squares method is then used to solve the multiple polynomial fitting equations simultaneously to obtain the fitting coefficients in the polynomial fitting model. These fitting coefficients are then substituted into the polynomial fitting model to obtain the relationship model between the spot position and the height of the measured surface.

[0073] Alternatively, the polynomial fitting model includes the following formula (1): (1) in, For the height of movement, Let A, B, C, and D be the positions of the light spot, and let A, B, C, and D be the fitting coefficients in the polynomial fitting model.

[0074] In one feasible approach, multiple sets of measurement data can be used to solve for the coefficients of the above formula (1).

[0075] The error function is defined as shown in the following formula (2): (2) The goal is to find A, B, C, and D such that E is minimized. The error function can be expressed in matrix form. ; Where Y is the FLS Measure Hight vector obtained from the above measurement, as shown below: .

[0076] X is a matrix composed of the position values ​​of the light spot on the CCD, as shown below: ; It is a coefficient vector with a solution: ; Finally, the solution can be obtained using the least squares method: .

[0077] Optionally, controlling the vertical movement of the workpiece stage includes: The workpiece stage is controlled to move multiple times in the vertical direction according to the preset movement step size, with the zero plane of the objective lens as the reference.

[0078] Optionally, the main controller can control stepper motor 1 and stepper motor 2 to move synchronously from bottom to top in steps of 1µm, so as to drive the FLS mechanism to move multiple times in the vertical direction according to a preset moving step length (such as 1µm) to obtain multiple moving heights.

[0079] Optionally, refer to Figure 10 As shown, step S104 above, determining the required adjustment height of the FLS mechanism based on its initial height and target height, includes: S1001. Determine the difference between the target height and the initial height, and use the difference as the required adjustment height for the FLS mechanism.

[0080] The method of controlling the FLS mechanism to move vertically based on height adjustment includes: S1002. If the difference is greater than zero, control the FLS mechanism to move downwards in the vertical direction. S1003. If the difference is less than zero, control the FLS mechanism to move upward in the vertical direction.

[0081] In one feasible approach, the difference between the calculated target height and the initial height is the required adjustment height for the FLS mechanism. If the difference is greater than zero (positive), the FLS mechanism is controlled to adjust downwards; if the difference is less than zero (negative), the FLS mechanism is controlled to adjust upwards. By synchronously moving the calculated height difference between the stepper motors 1 and 2 of the FLS mechanism, the FLS mechanism can be calibrated into position, thus achieving automatic calibration of the zero plane of the FLS mechanism.

[0082] Optionally, the calculation program corresponding to the above calibration method can be embedded into the system. When calibrating, it is only necessary to adjust the workpiece stage to move up or down from the initial height according to the set step size, and record the corresponding moving height H and spot position X. After N data acquisitions, the required calibration height difference can be automatically generated. Then the system controls the FLS mechanism to automatically complete the position adjustment to the calibration position, thereby realizing automated calibration and saving the time spent on calibration adjustment.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0084] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0085] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0086] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for calibrating the zero plane of the FLS mechanism in a lithography machine, characterized in that, The FSL mechanism includes: a light source, a projection slit, a projection mirror assembly, and at least one stepper motor; the method includes: The position of the light spot collected by the CCD detector is determined when the workpiece stage moves to different heights; wherein, the CCD detector is mounted on the workpiece stage; Based on the aforementioned moving heights and the corresponding spot positions, a relationship model between the spot position and the height of the measured surface is determined. The target spot position corresponding to the optical axis center position of the objective lens is input into the relationship model between the spot position and the height of the measured surface to calculate the target height. The target height is used to characterize the optimal focal plane height. The target spot position corresponding to the optical axis center position of the objective lens is predetermined. Based on the initial height and the target height of the FLS mechanism, the required adjustment height of the FLS mechanism is determined, and based on the adjustment height, the stepper motor is controlled to drive the FLS mechanism to move in the vertical direction to complete the zero plane calibration. The light source emitted by the projection component in the FLS mechanism is split into multiple sub-spots by a beam splitter, and the multiple sub-spots are not equidistantly distributed in the horizontal direction; Determining the position of the light spot collected by the CCD detector at different moving heights of the workpiece stage includes: At the same moving height, acquire imaging images of each of the sub-spots collected by the CCD detector; Based on the imaging images of each of the sub-spots, determine the position of the spot at the moving height; Determining the position of the light spot at the moving height based on the imaging images of each of the sub-light spots includes: Parabolic fitting is performed on the imaging images of each of the sub-spots to generate fitting curves for each of the sub-spots; The maximum value on the fitting curve of each light spot is taken as the light spot position of each sub-light spot; The average position of each sub-spot is determined, and the average value is used as the spot position at the moving height.

2. The method according to claim 1, characterized in that, The model for determining the relationship between the light spot position and the height of the measured surface based on each of the stated movement heights and the corresponding light spot positions includes: Based on each of the stated moving heights and the corresponding light spot positions, multiple sets of measurement data are constructed. By fitting the multiple sets of measurement data, a relationship model between the position of the light spot and the height of the measured surface is obtained.

3. The method according to claim 2, characterized in that, The process of fitting the multiple sets of measurement data to obtain the relationship model between the light spot position and the height of the measured surface includes: Obtain a pre-built polynomial fitting model; Substitute the multiple sets of measurement data into the polynomial fitting model to obtain multiple polynomial fitting equations; The least squares method is used to solve the multiple polynomial fitting equations simultaneously to obtain the fitting coefficients in the polynomial fitting model. Based on the polynomial fitting model and the fitting coefficients, a relationship model between the position of the light spot and the height of the measured surface is obtained.

4. The method according to claim 3, characterized in that, The polynomial fitting model includes: in, For the height of movement, Let A, B, C, and D be the positions of the light spot, and let A, B, C, and D be the fitting coefficients in the polynomial fitting model.

5. The method according to claim 1, characterized in that, Before determining the position of the light spot collected by the CCD detector at different moving heights of the workpiece stage, the method further includes: The workpiece stage is controlled to move multiple times in the vertical direction with the zero plane of the objective lens as a reference and according to a preset movement step size.

6. The method according to claim 1, characterized in that, Determining the required adjustment height of the FLS mechanism based on its initial height and target height includes: Determine the difference between the target height and the initial height, and use the difference as the required adjustment height for the FLS mechanism; The step of controlling the FLS mechanism to move vertically based on the adjusted height includes: If the difference is greater than zero, the FLS mechanism is controlled to move downwards in the vertical direction; If the difference is less than zero, the FLS mechanism is controlled to move upward in the vertical direction.

7. A photolithography apparatus, characterized in that, The lithography equipment includes: a workpiece stage, a lithography machine main controller, a CCD detector, and an FLS mechanism; the FLS mechanism includes: a light source, a projection slit, a projection imaging lens group, and an objective lens. The FLS mechanism is zero-plane calibrated by performing the method steps of any one of claims 1-6 using a photolithography device.

8. An electronic device, characterized in that, include: The device includes a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is in operation, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method as described in any one of claims 1-6.

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