Real-time calibration compensation method and system for workpiece table coordinates of a deformable e-beam lithography machine

Abstract

The application discloses a deformable electron beam lithography machine workpiece table coordinate real-time calibration compensation method and system, the method comprises the following steps: collecting the displacement of each measuring point, calculating the rotation parameters and translation parameters of the workpiece table coordinate system relative to the laser interferometer coordinate system; combining the pre-calibrated optical axis center position and the workpiece table target motion position, determining the deviation vector between the actual stop position and the theoretical target position of the workpiece table, as the motion error under the workpiece table coordinate system, and then generating the motion error compensation amount; performing first-order linear approximation on the mapping and transformation process, discarding the small amount of high order, and obtaining the simplified compensation amount; evaluating the maximum theoretical error; if the maximum theoretical error is less than the preset precision threshold, the simplified compensation amount is selected, otherwise the motion error compensation amount is selected; according to the compensation amount, fine adjustment deflection in the main field of view is carried out to offset the workpiece table positioning error. The application has the advantages of accurate and reliable calibration and compensation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, specifically to a method and system for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine. Background Technology

[0002] As semiconductor manufacturing technology continues to evolve towards higher integration and smaller dimensions, high-precision deformable electron beam lithography (VSB-EBL) machines, as an advanced exposure device, are gradually becoming a focus of attention in the domestic industry. Variable-Shape Electron Beam Lithography (VSB-EBL) is a core piece of equipment in semiconductor manufacturing for achieving sub-10 nm processes. It directly writes nanometer-scale patterns on wafers by dynamically controlling the shape and deflection path of the electron beam. With integrated circuit nodes evolving towards below 3 nm, the overlay accuracy requirements for lithography machines have reached the sub-nanometer level, and the core of overlay accuracy depends on the positioning accuracy of the stage and the global consistency of the coordinate system.

[0003] In high-precision electron beam lithography systems, the stage (or motion stage) plays a crucial role. Precise stage positioning not only affects the alignment accuracy of the pattern but also directly influences the size, shape, and relative position of the pattern after exposure. Traditional stages are mostly driven by motors for displacement; however, due to factors such as manufacturing tolerances of the mechanical structure, instability of the drive system, friction, dynamic deformation, thermal drift, and transmission errors, errors at the 2–3 μm level often occur during actual movement, far from meeting the requirements of nanoscale lithography. Furthermore, traditional theory typically assumes that the stage is orthogonal in the X and Y directions and only performs translational motion. However, in actual operation, at higher precision levels, rotational phenomena also occur, resulting in complex, multi-dimensional characteristics in the stage's motion error.

[0004] To overcome the aforementioned mechanical errors, a laser interferometer capable of providing ultra-high precision displacement measurement must be introduced. Utilizing the principle of light interference, a laser interferometer can achieve sub-nanometer level position measurement accuracy by detecting minute changes in the optical path difference. Commonly used laser interferometer systems employ highly stable lasers and precision optical components. By monitoring changes in interference fringes in real time, the displacement signal is converted into high-precision digital data, thereby compensating for the coarse adjustment errors inherent in traditional mechanical drives.

[0005] However, since the measurement coordinate system of the laser interferometer and the mechanical coordinate system of the workpiece stage usually have certain deviations and inconsistencies, a coordinate transformation algorithm must be used to establish a mapping relationship between the two in order to effectively apply the ultra-high precision data obtained by the laser interferometer to the position correction of the workpiece stage.

[0006] Current traditional calibration methods do not consider the following issues and technical challenges: 1. Non-orthogonality of the coordinate system during workpiece stage movement: In the actual workpiece stage, not only translation errors exist during movement, but rotation and tilt may also occur, resulting in a time-varying mapping relationship between the workpiece stage coordinate system and the laser interferometer coordinate system.

[0007] 2. Coordinate transformation and real-time mapping problem: It is necessary to achieve real-time transformation from the workpiece stage mechanical coordinate system to the laser interferometer coordinate system through accurate mathematical models and iterative optimization algorithms to ensure accurate matching of the two data and thus complete precise calibration.

[0008] 3. System Coupling and Dynamic Compensation: There are coupling effects between modules. For example, the workpiece stage motion error involved in the calibration process of the laser interferometer requires the corrected electron beam to be precisely deflected in a small range within the main field for compensation. The precise deflection of the electron beam requires the laser interferometer to achieve distortion correction in the main field range. This coupling affects the correction process. Summary of the Invention

[0009] To address the technical problems existing in the prior art, this invention provides a method and system for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine with dynamic and precise compensation.

[0010] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine includes the following steps: S1. Set up measurement points on the X and Y axes of the laser interferometer coordinate system and collect the displacement of each measurement point in real time during the movement of the workpiece stage; calculate the rotation and translation parameters of the workpiece stage coordinate system relative to the laser interferometer coordinate system based on the displacement of each measurement point, and establish a real-time mapping model between the two coordinate systems. S2. Based on rotation and translation parameters, combined with the pre-calibrated optical axis center position and the target motion position of the workpiece stage, the real-time mapping model is used to perform inverse coordinate transformation to determine the deviation vector between the actual stopping position of the workpiece stage and the theoretical target position; the deviation vector is used as the motion error in the workpiece stage coordinate system, and then transformed to the laser interferometer coordinate system through forward coordinate transformation to generate the motion error compensation amount for the current cycle. S3. Taking advantage of the fact that the rotation parameter is a minimum value, the mapping and transformation process in steps S1 and S2 is approximated by a first-order linear approximation. Higher-order small quantities are discarded, and the nonlinear operations involved are simplified to linear operations that only include addition and multiplication. The simplified compensation quantity calculation model is obtained, and the simplified compensation quantity is output. S4. Evaluate the maximum theoretical error introduced by discarding higher-order small quantities in step S3; if the maximum theoretical error is less than the preset accuracy threshold, select the simplified compensation amount generated in step S3; otherwise, select the motion error compensation amount generated in step S2. S5. Output the compensation amount selected in step S4 to the electron beam deflection system to drive the electron beam to perform fine-tuning deflection within the main field of view to compensate for the workpiece stage positioning error.

[0011] Preferably, in step S1, two measurement points are set on the X-axis of the laser interferometer coordinate system, with X-coordinates of respectively... and Obtain the displacement of two measurement points in the Y-axis direction. and According to the formula Calculate the rotation angle ; Set a measurement point on the Y-axis of the laser interferometer coordinate system, with its Y-coordinate as follows: Obtain the displacement of this measurement point in the X-axis direction. ,make , Establish translation parameters for the origin of the workpiece stage coordinate system in the laser interferometer coordinate system. The system of equations:

[0012] in ; Solving the system of equations yields The forward and inverse coordinate transformations employ rotation matrices. Implementation, in which for:

[0013] The positive transform uses:

[0014] in These are the coordinates in the workpiece stage coordinate system. These are the coordinates in the laser interferometer coordinate system; It is a rotation matrix; The inverse transform uses: .

[0015] Preferably, in step S2, the theoretical displacement vector corresponding to the theoretical target position The coordinates of the target point in the workpiece stage coordinate system Fixed position with optical axis center The result is obtained after coordinate transformation, specifically as follows: ; The actual displacement vector corresponding to the actual stopping position The coordinates of the workpiece stage point actually located below the center of the optical axis in the workpiece stage coordinate system Fixed position with optical axis center The result is obtained after coordinate transformation, specifically as follows: ; The deviation vector Theoretical displacement vector With actual displacement vector The difference is specifically as follows: ; The motion error compensation amount .

[0016] Preferably, in step S3, the first-order linear approximation includes: ,neglect For terms of order 1 and higher, the simplified formula for calculating the compensation amount is: .

[0017] Preferably, in step S4, the maximum theoretical error From the formula Estimate, of which This represents the maximum absolute value of each coordinate measurement. This is the error superposition coefficient; The angle is the rotation angle.

[0018] Preferably, step S5 is followed by step S6: after the current compensation cycle ends, real-time displacement data of each measurement point is collected again by the laser interferometer and fed back to step S1, triggering the mapping update and error calculation of the next cycle, forming a continuous closed-loop dynamic calibration.

[0019] Preferably, the method further includes an auxiliary calibration step: setting a marker plate on the workpiece stage, using a backscattered electronic detection system to read the position signal of the marker plate, and comparing the position signal with the measurement data of the laser interferometer at the same time; when the deviation between the two exceeds a preset verification threshold, triggering the re-execution of steps S1 to S4 to correct the mapping model parameters.

[0020] The present invention also discloses a computer program product, comprising a computer program that, when executed by a processor, performs the steps of the method described above.

[0021] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, the computer program executing the steps of the method described above when run by a processor.

[0022] The present invention also discloses a real-time calibration and compensation system for workpiece stage coordinates of a deformable electron beam lithography machine, comprising a memory and a processor connected to each other, wherein the memory stores a computer program, and the computer program executes the steps of the method described above when run by the processor.

[0023] Compared with the prior art, the advantages of the present invention are as follows: This invention achieves sub-nanometer displacement detection by introducing a laser interferometer, and employs multiple technical measures such as backscattering marker plate assistance, main field fine-tuning deflection, coordinate transformation and closed-loop dynamic compensation to ultimately establish a precise mapping between the workpiece stage coordinate system and the laser interferometer coordinate system, providing a reliable technical guarantee for achieving ultra-high precision exposure.

[0024] This invention constructs a mapping model between the laser interferometer coordinate system and the workpiece stage mechanical coordinate system. By arranging two measurement points on the X-axis and one measurement point on the Y-axis, and using the measurement results of the laser interferometer, the translation and rotation angle of the origin of the workpiece stage coordinate system are obtained, and the position of the origin of coordinate system 2 in coordinate system 1 is accurately determined, thus achieving high-precision mapping between the two coordinate systems.

[0025] This invention achieves dynamic compensation for workpiece stage motion error: during the workpiece stage motion, ultra-high precision displacement measurement data of the laser interferometer is acquired in real time, and the offset error vector between the current point and the center of the optical axis is calculated based on this data. This error is then transformed from the workpiece stage coordinate system to the interferometer coordinate system. Combined with the fine-tuning deflection of the electron beam main field, dynamic and precise compensation is achieved to ensure the precise landing point of the electron beam in the main field.

[0026] This invention features a simplified first-order compensation algorithm suitable for FPGAs: to meet real-time requirements, higher-order small quantities are removed in the motion deviation solution, resulting in a first-order approximate compensation formula containing only addition and multiplication operations; without the need for trigonometric functions, inverse trigonometric functions, or division, the compensation amount can be calculated within 3 clock cycles, greatly improving the efficiency and real-time performance of the underlying hardware implementation.

[0027] This invention achieves high-order error truncation and sub-nanometer precision guarantee: for the maximum rotation angle (≤10) within a maximum stroke of 100mm. -4 rad and 10 -5 The high-order error derivation analysis was performed on each rad to verify that the residual error after discarding second-order and higher terms is ≤3nm (in the worst case), ensuring that the calculation error within the adjacent main field range (1mm) is less than 0.1nm, which meets the stringent requirements of sub-nanometer lithography for positioning accuracy. Attached Figure Description

[0028] Figure 1 This is a schematic diagram showing the positional relationship between the laser interferometer coordinate system and the workpiece stage coordinate system in an embodiment of the present invention.

[0029] Figure 2 The following are the initial and motion state diagrams of the laser interferometer coordinate system and the workpiece stage coordinate system according to an embodiment of the present invention; (a) is the initial state diagram; (b) is the motion state diagram.

[0030] Figure 3 This is a flowchart of the real-time calibration and compensation method for workpiece stage coordinates in a deformable electron beam lithography machine, according to an embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 3 As shown in the embodiment of the present invention, the real-time calibration and compensation method for workpiece stage coordinates of a deformable electron beam lithography machine includes the following steps: S1. Establish the transformation model between the laser interferometer coordinate system and the workpiece stage coordinate system. like Figure 1 As shown, coordinate system O1-X1-Y1 (referred to as coordinate system 1) is the laser interferometer coordinate system, and coordinate system O2-X2-Y2 (referred to as coordinate system 2) is the workpiece stage coordinate system. Initially, when there is no movement, the two coordinate systems coincide. The movement of the workpiece stage causes a shift and rotation in coordinate system 2. Two laser instrument measurement points are distributed along the X-axis of coordinate system 1 to measure the Y-direction movement of the X-axis of coordinate system 2 and the rotation angle of coordinate system 2. The coordinate positions of the two points on the X-axis are as follows: and A laser measurement point is distributed on the Y-axis of coordinate system 1, and its corresponding position on the Y-axis is: .

[0033] The workpiece stage can be considered a rigid body; therefore, its movement can be assumed to involve only translation and rotation. If there is no rotation during the movement, then the corresponding measured values ​​will have... , Therefore, in this case, the origin of coordinate system 2 can be directly solved, and the other points in coordinate system 2 of the workpiece stage can be directly represented by the laser interferometer coordinate system. However, since the workpiece stage rotates to a certain extent, the measurement results of the laser interferometer cannot be directly used to represent the origin in coordinate system 2, that is, the origin of coordinate system 2 is unknown. Specific value.

[0034] The key to mapping between the laser interferometer coordinate system 1 and the workpiece stage coordinate system 2 lies in calculating the position of the origin in coordinate system 2 relative to coordinate system 1 using measurements taken by the laser interferometer. Assuming coordinate system 2 has undergone motion as follows: Figure 1 As shown, based on the above relationships, we obtain:

[0035] in:

[0036] All three parameters mentioned above are known constants (e.g.) ) or the results obtained from laser interferometer measurements (such as and Therefore, the above solution regarding... The solution to the linear equation in two variables is:

[0037] Since the motion of the workpiece stage coordinate system can be decomposed into two transformation operations: translation and rotation, that is, the workpiece stage first undergoes vector transformation... After the translation operation, then perform... The final motion state of the workpiece stage is obtained through angular rotation. Since the coordinates in workpiece stage coordinate system 2 need to be represented in laser interferometer coordinate system 1, a rotation operation must be performed first, followed by translation calculation. Rotation matrix. for:

[0038] Therefore, the coordinates of a certain point in the workpiece coordinate system 2 need to be determined. The coordinate position in coordinate system 1 of the laser interferometer is:

[0039] This solution yields the actual coordinates of a point on the workpiece stage in the actual laser coordinate system. Similarly, the inverse transformation process can be performed, which involves representing the coordinates in coordinate system 1 in coordinate system 2.

[0040] This completes the establishment of the mathematical model for the forward and inverse transformations between the two coordinate systems, laying the foundation for subsequent motion deviation calculations.

[0041] S2. Solution of motion deviation Given an ideal coordinate vector, it is desirable for the workpiece stage to move to the given ideal coordinate position. However, due to errors in the workpiece stage's motion, it cannot move precisely to the ideal coordinate position, and the movement is essentially off-target. This is unacceptable for sub-nanometer positioning accuracy requirements, so compensation is needed using the measurement results from a laser interferometer.

[0042] like Figure 2As shown in (a), after the workpiece stage is reset, the coordinate system of the laser interferometer coincides with the coordinate system of the workpiece stage, and at this time the center of the optical axis is located at... At this point, the coordinates of the optical axis center relative to the workpiece stage are also fixed in the laser interferometer coordinate system. We now want to move the workpiece stage so that it is located at coordinates... The point on the top is moved below the center of the optical axis, such as... Figure 2 As shown in (b), the workpiece stage undergoes translational and rotational motions during the movement, and motion errors are generated during the process, resulting in... It did not land precisely at the center of the optical axis, but rather at a point on the workpiece stage. It fell to the center of the optical axis, and this point is... exist Random error within.

[0043] Based on the aforementioned derivation, the position of the origin in coordinate system 2 within coordinate system 1 can be determined. Correspondingly, it is necessary to determine the coordinates of the point currently located below the optical axis center in workpiece stage coordinate system 2 after the motion. Given that the coordinates of the optical axis center corresponding to coordinate system 1 of the laser interferometer are... That is:

[0044] Therefore, we can determine the total movement of the workpiece stage coordinates, which is the point in coordinate system 2. Moved to a point in coordinate system 2 The actual displacement vector in coordinate system 2 is: ; Theoretically, it is necessary to adjust the coordinate system under coordinate system 2. The point moves to the center of the optical axis, that is, the theoretical displacement vector in coordinate system 2 is: ; This represents the theoretical distance the workpiece stage needs to move, which is a known quantity. Therefore, the displacement vector of the motion error in coordinate system 2 is:

[0045] Since the coordinate compensation amount is measured in the workpiece stage coordinate system, while the deflection compensation is aligned to the laser interferometer coordinate system, it is necessary to convert the compensation amount to the laser interferometer coordinate system. Therefore, the final motion error compensation amount used for deflection is:

[0046] The above steps provide a complete process from theoretical displacement and actual measurement to error vector calculation and conversion to the laser interferometer coordinate system, providing accurate numerical basis for real-time compensation.

[0047] S3. Construct a simplified model for solving motion deviations. Since high-precision, real-time motion error calculation is required, the above motion error calculation process needs to be simplified to a final, implementable form to facilitate the subsequent calculation and implementation of fixed-point algorithms based on FPGA and other underlying devices.

[0048] The rotation angle was confirmed based on measurements taken using existing equipment. It is a very small value, therefore:

[0049] Original form:

[0050] Remove Item, we get:

[0051] The previous derivation yielded the following:

[0052] The above Substitute, ignoring second-order minor quantities:

[0053] For error :

[0054]

[0055] First-order approximation:

[0056] Substitute into the above formula:

[0057] Remove second order After that, it can ultimately be written as:

[0058] This is the final motion error compensation amount under the first-order approximation, in the above formula, It is the theoretical displacement vector. These are the measurements taken by the laser interferometer in the X and Y directions. These are known quantities obtained by measurement in the laser interferometer coordinate system, therefore, in obtaining... The motion compensation in the laser interferometer coordinate system can be calculated in real time during measurement.

[0059] As shown in the above formula, the solution for motion error compensation ultimately involves only the simplest addition and multiplication operations. In FPGA or DSP, the solution can be implemented using the most efficient multiplication and addition operations, avoiding the lengthy and inefficient implementation processes involving trigonometric functions, inverse trigonometric functions, and division, thus ensuring the high efficiency and real-time characteristics of the calculation.

[0060] S4. Higher-order truncation error analysis and accuracy verification To further derive the higher-order errors caused by different maximum rotation angles within the workpiece stage stroke, based on currently measured rotation angle values, during the process of the workpiece stage moving 100mm along the X-axis, the maximum rotation angle is between Here, we will focus on the maximum error. and We will analyze two scenarios.

[0061] remember:

[0062] For basic trigonometric functions and The approximations are shown in the table below:

[0063] Error-dominated part.

[0064] for Error:

[0065] therefore:

[0066] for Original form:

[0067] Approximate value:

[0068] Dominant discard magnitude:

[0069] Similarly, we can conclude that:

[0070] For actual motion vector displacement, use:

[0071] Introducing sources of error: The corresponding higher-order error is item; The higher-order error of approximate discarding is also... item; The higher-order error of approximate discarding is Therefore:

[0072] Therefore, for The measurement error is equivalent to .

[0073] Final rotation correction Its exact solution is Approximate Dominant abandonment:

[0074] Similarly, Error analysis.

[0075]

[0076] Therefore, the overall dominant error order is... Converted to units of length, the absolute error is approximately no more than: Where the constant It comes from taking the lead in each step. When the error magnitudes are superimposed with the same sign in the worst case, the sum of the numerical coefficients preceding each term.

[0077] The total error previously obtained was approximately:

[0078] The following estimates each :

[0079] The three main items , , Add:

[0080] Taking a slightly conservative upper bound of approximately 3, we obtain the originally given range of coefficients:

[0081] For higher-order superpositions that can be ignored Level item: from as well as Magnitude For a formation of 100mm, at most [the following will occur] mm, that is This can be completely ignored. For overlapping terms: such as... and Combinations, in the form of Even smaller, it can be ignored.

[0082] Pick mm, substitute two :

[0083] Therefore, using the aforementioned motion deviation calculation model, even if the rotation angle within a stroke of 100mm is... Within this range, the maximum calculation error of the model is only about 3nm. Therefore, for two adjacent home fields (home field size is 1mm), the misalignment error between them is only 0.03nm. If the rotation angle within a stroke of 100mm is... Within this range, the corresponding model calculation error is even smaller, at 0.03 nm. Therefore, based on the maximum rotation angle generated within the stroke range and according to this higher-order error model, the calculation error value generated within the stroke range can be determined.

[0084] S5. Closed-loop dynamic compensation and real-time iteration After obtaining the motion error compensation amount (Δx, Δy) in step S2 or S3 (in actual implementation, an accurate model or a simplified model can be selected according to hardware resources and accuracy requirements), this compensation amount is output to the electron beam deflection system in real time. The electron beam is fine-tuned within the main field based on this compensation amount, making the actual exposure position close to the target position. Simultaneously, after compensation is executed, the laser interferometer continuously monitors the workpiece stage position change in real time, feeding back the new measurement data to step S1 to update the mapping model parameters (such as θ, y). 12 (e.g., x3), and repeat steps S1 to S4 (or steps S1 to S3) in the next control cycle to form a closed-loop dynamic compensation mechanism.

[0085] This closed-loop process runs continuously throughout the entire movement of the workpiece stage, ensuring that the mapping relationship between the workpiece stage coordinate system and the laser interferometer coordinate system remains accurate at any given time. The compensation amount is updated in real time, thereby dynamically offsetting the effects of mechanical motion errors, thermal drift, and system coupling effects. The coupling effects between modules—including the impact of workpiece stage motion errors on laser interferometer calibration, and the dependence of electron beam deflection on main field distortion correction—are addressed through the aforementioned real-time iteration and coordinate transformation, achieving coordinated optimization of overall system calibration and dynamic compensation.

[0086] This invention achieves sub-nanometer displacement detection by introducing a laser interferometer, and employs multiple technical measures such as backscattering marker plate assistance, main field fine-tuning deflection, coordinate transformation and closed-loop dynamic compensation to ultimately establish a precise mapping between the workpiece stage coordinate system and the laser interferometer coordinate system, providing a reliable technical guarantee for achieving ultra-high precision exposure.

[0087] This invention constructs a mapping model between the laser interferometer coordinate system and the workpiece stage mechanical coordinate system. By arranging two measurement points on the X-axis and one measurement point on the Y-axis, and using the measurement results of the laser interferometer, the translation and rotation angle of the origin of the workpiece stage coordinate system are obtained, and the position of the origin of coordinate system 2 in coordinate system 1 is accurately determined, thus achieving high-precision mapping between the two coordinate systems.

[0088] This invention achieves dynamic compensation for workpiece stage motion error: during the workpiece stage motion, ultra-high precision displacement measurement data of the laser interferometer is acquired in real time, and the offset error vector between the current point and the center of the optical axis is calculated based on this data. This error is then transformed from the workpiece stage coordinate system to the interferometer coordinate system. Combined with the fine-tuning deflection of the electron beam main field, dynamic and precise compensation is achieved to ensure the precise landing point of the electron beam in the main field.

[0089] This invention features a simplified first-order compensation algorithm suitable for FPGAs: to meet real-time requirements, higher-order small quantities are removed in the motion deviation solution, resulting in a first-order approximate compensation formula containing only addition and multiplication operations; without the need for trigonometric functions, inverse trigonometric functions, or division, the compensation amount can be calculated within 3 clock cycles, greatly improving the efficiency and real-time performance of the underlying hardware implementation.

[0090] This invention achieves high-order error truncation and sub-nanometer precision guarantee: for the maximum rotation angle (≤10) within a maximum stroke of 100mm. -4 rad and 10 -5 The high-order error derivation analysis was performed on each rad to verify that the residual error after discarding second-order and higher terms is ≤3nm (in the worst case), ensuring that the calculation error within the adjacent main field range (1mm) is less than 0.1nm, which meets the stringent requirements of sub-nanometer lithography for positioning accuracy.

[0091] The present invention also discloses a computer program product, comprising a computer program that, when executed by a processor, performs the steps of the method described above.

[0092] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, the computer program executing the steps of the method described above when run by a processor.

[0093] The present invention also discloses a real-time calibration and compensation system for workpiece stage coordinates of a deformable electron beam lithography machine, comprising a memory and a processor connected to each other, wherein the memory stores a computer program, and the computer program executes the steps of the method described above when run by the processor.

[0094] The present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium includes: any entity or device capable of carrying computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. The memory is used to store computer programs and / or modules. The processor implements various functions by running or executing the computer programs and / or modules stored in the memory, and by calling data stored in the memory. The memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0095] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine, characterized in that, Includes the following steps: S1. Set up measurement points on the X and Y axes of the laser interferometer coordinate system and collect the displacement of each measurement point in real time during the movement of the workpiece stage; calculate the rotation and translation parameters of the workpiece stage coordinate system relative to the laser interferometer coordinate system based on the displacement of each measurement point, and establish a real-time mapping model between the two coordinate systems. S2. Based on rotation and translation parameters, combined with the pre-calibrated optical axis center position and the target motion position of the workpiece stage, the real-time mapping model is used to perform inverse coordinate transformation to determine the deviation vector between the actual stopping position of the workpiece stage and the theoretical target position; the deviation vector is used as the motion error in the workpiece stage coordinate system, and then transformed to the laser interferometer coordinate system through forward coordinate transformation to generate the motion error compensation amount for the current cycle. S3. Taking advantage of the fact that the rotation parameter is a local minimum, the mapping and transformation process in steps S1 and S2 is approximated by a first-order linear approximation. Higher-order small quantities are discarded, and the nonlinear operations involved are simplified to linear operations containing only addition and multiplication to obtain the simplified compensation quantity. S4. Evaluate the maximum theoretical error introduced by discarding higher-order small quantities in step S3; if the maximum theoretical error is less than the preset accuracy threshold, select the simplified compensation amount generated in step S3; otherwise, select the motion error compensation amount generated in step S2. S5. Output the compensation amount selected in step S4 to the electron beam deflection system to drive the electron beam to perform fine-tuning deflection within the main field of view to compensate for the workpiece stage positioning error.

2. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to claim 1, characterized in that, In step S1, two measurement points are set on the X-axis of the laser interferometer coordinate system, with X-coordinates of respectively... and Obtain the displacement of two measurement points in the Y-axis direction. and According to the formula Calculate the rotation angle ; Set a measurement point on the Y-axis of the laser interferometer coordinate system, with its Y-coordinate as follows: Obtain the displacement of this measurement point in the X-axis direction. ,make , Establish translation parameters for the origin of the workpiece stage coordinate system in the laser interferometer coordinate system. The system of equations: in ; Solving the system of equations yields The forward and inverse coordinate transformations employ rotation matrices. Implementation, in which for: The positive transform uses: in These are the coordinates in the workpiece stage coordinate system. These are the coordinates in the laser interferometer coordinate system; It is a rotation matrix; The inverse transform uses: 。 3. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to claim 2, characterized in that, In step S2, the theoretical displacement vector corresponding to the theoretical target position The coordinates of the target point in the workpiece stage coordinate system Fixed position with optical axis center The result is obtained after coordinate transformation, specifically as follows: ; The actual displacement vector corresponding to the actual stopping position The coordinates of the workpiece stage point actually located below the center of the optical axis in the workpiece stage coordinate system Fixed position with optical axis center The result is obtained after coordinate transformation, specifically as follows: ; The deviation vector Theoretical displacement vector With actual displacement vector The difference is specifically as follows: ; The motion error compensation amount .

4. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to claim 3, characterized in that, In step S3, the first-order linear approximation includes: ,neglect For terms of order 1 and higher, the simplified formula for calculating the compensation amount is: 。 5. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to any one of claims 1-4, characterized in that, In step S4, the maximum theoretical error From the formula Estimate, of which This represents the maximum absolute value of each coordinate measurement. This is the error superposition coefficient; The angle is the rotation angle.

6. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to any one of claims 1-4, characterized in that, Step S5 is followed by step S6: After the current compensation cycle ends, the real-time displacement data of each measurement point is collected again by the laser interferometer and fed back to step S1, triggering the mapping update and error calculation of the next cycle, forming a continuous closed-loop dynamic calibration.

7. The method for real-time calibration and compensation of workpiece stage coordinates in a deformable electron beam lithography machine according to any one of claims 1-4, characterized in that, It also includes an auxiliary calibration step: setting a marker plate on the workpiece stage, using a backscattered electronic detection system to read the position signal of the marker plate, and comparing the position signal with the measurement data of the laser interferometer at the same time; when the deviation between the two exceeds the preset verification threshold, steps S1 to S4 are re-executed to correct the mapping model parameters.

8. A computer program product, comprising a computer program, characterized in that, The computer program is executed by the processor to perform the steps of the method as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-7.

10. A real-time calibration and compensation system for workpiece stage coordinates of a deformable electron beam lithography machine, comprising a memory and a processor interconnected, wherein the memory stores a computer program, characterized in that... The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-7.

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