Optical device deformation compensation method and system, and lithography machine

Abstract

An optical device deformation compensation method and system, and a photolithography machine, wherein the optical device is used to transfer a pattern on a mask to a wafer, the optical device deformation compensation method comprises: determining a region with aberration in an actually formed pattern on the wafer according to a difference between the actually formed pattern and a preset pattern; obtaining a deformation compensation amount of a corresponding region of the optical device according to an actual aberration in the region with aberration; and generating a corresponding compensation control signal according to the deformation compensation amount of the corresponding region of the optical device, and controlling a corresponding compensation device to compensate the corresponding region of the optical device. By using the above scheme, the local deformation of the optical device can be accurately compensated, thereby improving the imaging quality of the optical device.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of semiconductor manufacturing technology, and in particular to a method and system for compensating for deformation of optical devices and a photolithography machine. Background Technology

[0002] In semiconductor manufacturing, photolithography is a crucial technology for pattern transfer, and its control precision and resolution directly determine the semiconductor yield. Among the many factors affecting photolithography, the quality of the lithography machine's optical components plays a decisive role, as the quality of the image is directly determined by the optical components.

[0003] During the exposure process, the optical components deform due to the irradiation of high-power laser light, resulting in certain aberrations in the final image. Currently, to reduce the impact of optical component deformation on imaging, piezoelectric sensors are typically used to control the displacement of the optical components, and displacement sensors detect the displacement of the optical components to compensate for the deformation.

[0004] However, in practice, using piezoelectric elements and displacement sensors to compensate for the deformation of optical devices can only provide uniform compensation for the entire optical device. Summary of the Invention

[0005] In view of this, the embodiments of this specification provide a method and system for compensating for deformation of optical devices, and a lithography machine, which can accurately compensate for local deformation of optical devices, thereby improving the imaging quality of optical devices.

[0006] First, this specification provides an embodiment of an optical device deformation compensation method, wherein the optical device is used to transfer a pattern on a photomask onto a wafer, and the method includes:

[0007] Based on the difference between the actual pattern formed on the wafer surface and the preset pattern, the regions in the actual pattern that contain aberrations are determined;

[0008] Based on the actual aberration in the region where aberration exists, the deformation compensation amount for the corresponding region of the optical device is obtained;

[0009] Based on the deformation compensation amount of the corresponding region of the optical device, a corresponding compensation control signal is generated to control the corresponding compensation device to compensate the corresponding region of the optical device.

[0010] Optionally, obtaining the deformation compensation amount for the corresponding region of the optical device based on the actual aberration in the region where the aberration exists includes:

[0011] Based on the actual aberrations in the aberration-affected regions, the Zernike constant aberrations present in the corresponding regions of the optical device are obtained;

[0012] The obtained Zernike constant aberration is converted into the deformation compensation amount of the corresponding region of the optical device.

[0013] Optionally, the step of generating a corresponding compensation control signal based on the deformation compensation amount of the corresponding region of the optical device, and controlling the corresponding compensation device to compensate the corresponding region of the optical device, includes:

[0014] Based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, the compensation voltage of the compensation device at the corresponding position is determined, and a compensation voltage signal is generated.

[0015] The compensation voltage signal is output to the corresponding compensation device to compensate the corresponding area of ​​the optical device.

[0016] Optionally, the compensation device that outputs the compensation voltage signal to the corresponding position to compensate the corresponding area of ​​the optical device includes:

[0017] According to the compensation voltage signal, the compensation device applies a force to the corresponding area of ​​the optical device to drive the optical device to move and compensate the corresponding area of ​​the optical device.

[0018] Optionally, the step of applying a force to a corresponding region of the optical device according to the compensation voltage signal to drive the optical device to move and compensate the corresponding region of the optical device includes:

[0019] According to the compensation voltage signal, the compensation device applies a force to the corresponding area of ​​the optical device in the direction perpendicular to the wafer surface to drive the optical device to move and compensate for the deformation of the corresponding area of ​​the optical device.

[0020] Optionally, the optical device deformation compensation method further includes:

[0021] The displacement of the corresponding region of the optical device is detected, and when it is determined that the displacement of the optical device is equal to the deformation of the corresponding region of the optical device, the output of the compensation control signal to the compensation device at the corresponding position is stopped.

[0022] Accordingly, embodiments of this specification also provide an optical device deformation compensation system, wherein the optical device is used to transfer a pattern on a photomask onto a wafer, and the deformation compensation system includes an aberration acquisition device, a compensation control device, and a compensation device, wherein:

[0023] The aberration acquisition device is adapted to determine the region in the actually formed pattern that contains aberrations based on the difference between the actual pattern formed on the wafer surface and the preset pattern.

[0024] The compensation control device is adapted to obtain the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region where the aberration exists; and to generate a corresponding compensation control signal based on the deformation compensation amount of the corresponding region of the optical device.

[0025] The compensation device is adapted to compensate the corresponding area of ​​the optical device according to the compensation control signal.

[0026] Optionally, the compensation control device includes a compensation amount calculation unit and a compensation control unit, wherein:

[0027] The compensation calculation unit is adapted to obtain the Zernike constant aberration in the corresponding region of the optical device based on the actual aberration in the region where the aberration exists, and to convert the obtained Zernike constant aberration into the deformation compensation amount of the corresponding region of the optical device.

[0028] The compensation control unit is adapted to determine the corresponding region based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage.

[0029] Optionally, the compensation device is adapted to apply a force to a corresponding region of the optical device according to the compensation voltage signal, so as to drive the optical device to move and compensate the corresponding region of the optical device.

[0030] Optionally, the optical device deformation compensation system further includes:

[0031] A displacement detection device is adapted to detect the displacement of the corresponding area of ​​the optical device and output it to the compensation control device;

[0032] The compensation control device is further adapted to stop outputting the compensation voltage signal to the compensation device at the corresponding position when it is determined that the displacement of the optical device is equal to the deformation compensation of the corresponding region of the optical device.

[0033] Optionally, the compensation device includes a piezoelectric ceramic actuator, and the displacement detection device includes a displacement sensor;

[0034] Multiple piezoelectric ceramic actuators and multiple displacement sensors are respectively arranged on opposite sides of the optical device in the direction perpendicular to the wafer surface, and the positions of the multiple piezoelectric ceramic actuators and the multiple displacement sensors correspond one-to-one.

[0035] This specification also provides a lithography machine, including:

[0036] Optical devices suitable for transferring patterns from a photomask onto a wafer;

[0037] The optical device deformation compensation system described in any of the foregoing embodiments is suitable for compensating for the deformation of the optical device.

[0038] Optionally, the optical device is a lens.

[0039] By employing the optical device deformation compensation scheme provided in the embodiments of this specification, the region with aberrations in the actual pattern formed on the wafer surface can be determined based on the difference between the actual pattern formed and the preset pattern. Since the region with aberrations in the pattern can reflect the deformation of the corresponding region of the optical device, the deformation compensation amount of the corresponding region of the optical device can be obtained based on the actual aberration in the region with aberrations. Then, based on the deformation compensation amount of the corresponding region of the optical device, a corresponding compensation control signal can be generated to control the corresponding compensation device to compensate the corresponding region of the optical device with deformation. Therefore, the local deformation of the optical device can be accurately compensated, thereby improving the imaging quality of the optical device.

[0040] Furthermore, based on the actual aberrations in the regions where aberrations exist, the Zernike constant aberrations in the corresponding regions of the optical device can be obtained. By converting the Zernike constant aberrations into the deformation compensation amount of the corresponding regions of the optical device, the difficulty of calculating the deformation compensation amount of the optical device can be reduced, and the calculation efficiency can be improved.

[0041] Furthermore, based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, the compensation voltage of the compensation device at the corresponding position can be determined, thereby generating a corresponding compensation voltage signal. This enables the compensation device at the corresponding position to accurately compensate the deformed region of the optical device based on the compensation voltage signal.

[0042] Furthermore, by detecting the displacement of the corresponding region of the optical device, when it is determined that the displacement of the optical device is equal to the deformation of the corresponding region of the optical device, the compensation control signal can be stopped from being output to the compensation device at the corresponding position. This can prevent the compensation device from overcompensating the deformation region of the optical device, thereby further improving the compensation accuracy.

[0043] Furthermore, the compensation device includes a piezoelectric ceramic actuator, and the displacement detection device includes a displacement sensor. By setting multiple piezoelectric ceramic actuators and multiple displacement sensors on opposite sides of the optical device in the direction perpendicular to the wafer surface, and with each piezoelectric ceramic actuator corresponding to a displacement sensor, when an area with aberrations is determined in the actual formed pattern, the piezoelectric ceramic actuator can compensate for the deformation of the corresponding area of ​​the optical device, and the displacement sensor corresponding to the piezoelectric ceramic actuator can detect the displacement of the corresponding area of ​​the optical device, thereby improving the compensation accuracy. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art in this specification will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A schematic diagram of an optical device for imaging is shown;

[0046] Figure 2 A schematic diagram of an optical device deformation compensation system is shown.

[0047] Figure 3 A flowchart of an optical device deformation compensation method according to an embodiment of this specification is shown;

[0048] Figure 4 A flowchart illustrating compensation for a corresponding region of an optical device in a specific application scenario of an embodiment of this specification is shown.

[0049] Figure 5 A schematic diagram of the structure of an optical device deformation compensation system according to an embodiment of this specification is shown;

[0050] Figure 6 This document shows a schematic diagram of the structure of an optical device deformation compensation system in a specific application scenario according to an embodiment of this specification.

[0051] Figure 7 A schematic diagram of the structure of a lithography machine according to an embodiment of this specification is shown. Detailed Implementation

[0052] To help those skilled in the art better understand the aberration problems in imaging in the prior art, a brief explanation is given below with reference to an imaging schematic diagram of an optical device.

[0053] Reference Figure 1 The diagram shows an imaging schematic of an optical device. The light L emitted by the light source of the lithography machine (not shown) passes through the mask 11 and reaches the optical device 12. After being refracted by the optical device 12, the light L1 reaches the surface of the wafer 13 and converges to the center O1 of the wafer 13, thereby transferring the pattern on the mask 11 to the wafer 13, so that the actual pattern formed is the same as the preset pattern (i.e. the pattern on the mask 11).

[0054] Continue to refer to Figure 1If the optical device 12 is deformed, for example, after being refracted by the optical device 12, light L2 may be formed and converged to point O2 on the surface of wafer 13. The convergence point O2 is deviated from the center O1 of wafer 13, causing the actual pattern formed to differ from the preset pattern (i.e. the pattern on mask 11), that is, an aberration d is generated.

[0055] To reduce the impact of optical device deformation on imaging, as described in the background art, piezoelectric sensors are currently commonly used to control the displacement of optical devices, and displacement sensors detect the displacement of optical devices to compensate for the deformation of optical devices.

[0056] However, in practice, using piezoelectric elements and displacement sensors to compensate for the deformation of optical devices can only provide uniform compensation for the entire optical device, resulting in low compensation accuracy.

[0057] Reference Figure 2 The diagram shown is a structural schematic of an optical device deformation compensation system. Figure 2 The optical device 2A is connected to the moving shaft 23 and the scale 25 via the connecting shaft 24. The moving shaft 23 can move up and down, driving the connecting shaft 24 to move as well. The entire optical device 2A and the scale 25 can then move up and down with the moving shaft 23. The displacement sensor 26 can detect the distance the optical device 2A has moved by detecting changes in the scale value on the scale 25. Based on this distance, different voltages are applied to the driver 21. Multiple piezoelectric elements 22 mounted on the driver 21 can clamp / unclamp, driving the moving shaft 23 to move up and down to compensate for the deformation of the optical device. Specifically, when the voltage applied to the driver 21 increases, the piezoelectric elements 22 clamp the moving shaft; when the voltage applied to the driver 21 decreases, the piezoelectric elements 22 unclamp the moving shaft.

[0058] However, when the above-mentioned device is used, as the moving shaft 23 moves up and down, the entire optical device 2A moves with the moving shaft 23. Therefore, if the optical device 2A is deformed, only the optical device 2A as a whole can be compensated uniformly, resulting in low compensation accuracy.

[0059] To address the aforementioned technical problems, embodiments of this specification provide an optical device deformation compensation method. Based on the difference between the actual pattern formed on the wafer surface and a preset pattern, regions with aberrations in the actual pattern can be determined. Since regions with aberrations reflect the deformation of corresponding regions of the optical device, the deformation compensation amount for the corresponding region of the optical device can be obtained based on the actual aberrations in these regions. Furthermore, based on the deformation compensation amount for the corresponding region of the optical device, a corresponding compensation control signal can be generated to control a corresponding compensation device to compensate for the deformation in the corresponding region of the optical device. Therefore, precise compensation for local deformation of the optical device can be achieved, thereby improving the imaging quality of the optical device.

[0060] To enable those skilled in the art to have a clearer understanding of the technical concepts, principles, advantages, etc. contained in the embodiments of this specification, a detailed description is provided below with reference to the accompanying drawings, through specific embodiments, and in conjunction with specific application scenarios.

[0061] Reference Figure 3 The flowchart shown in this specification illustrates a method for compensating for deformation of an optical device in an embodiment of the invention. The optical device is used to transfer a pattern from a photomask onto a wafer. Specifically, the deformation of the optical device can be compensated according to the following steps:

[0062] S31, based on the difference between the actual pattern formed on the wafer surface and the preset pattern, determine the region in the actual pattern that has aberrations.

[0063] Specifically, when using optical devices to transfer a pattern from a photomask onto a wafer, the optical devices may deform, resulting in a difference between the actual pattern formed on the wafer surface and the preset pattern (e.g., the pattern on the photomask). According to the principle of photolithography, the pattern on the photomask and the pattern transferred onto the wafer should be consistent. Therefore, based on the resulting difference, it is possible to determine the areas with aberrations in the actual pattern formed.

[0064] S32, based on the actual aberration in the region where the aberration exists, obtain the deformation compensation amount for the corresponding region of the optical device.

[0065] Specifically, since the areas of an image with aberrations can reflect the deformation of the corresponding areas of the optical device, the deformation compensation amount of the corresponding areas of the optical device can be obtained based on the actual aberrations in the areas with aberrations.

[0066] S23, Based on the deformation compensation amount of the corresponding area of ​​the optical device, a corresponding compensation control signal is generated to control the corresponding compensation device to compensate the corresponding area of ​​the optical device.

[0067] Specifically, through steps S21 and S22, it is possible to determine which region of the optical device is deformed and the corresponding deformation compensation amount based on the actual aberration in the region where aberration exists. Based on the region of the optical device that is deformed and the corresponding deformation compensation amount, a corresponding compensation control signal can be generated to control the corresponding compensation device to compensate the corresponding region (the region where the deformation occurs) of the optical device.

[0068] In some embodiments of this specification, the deformation of the optical device can be compensated in a targeted manner in multiple different directions based on the actual aberrations in the region where aberrations exist.

[0069] As can be seen from the above compensation control process, since the area of ​​the image with aberrations can reflect the deformation of the corresponding area of ​​the optical device, the deformation compensation amount of the corresponding area of ​​the optical device can be obtained based on the actual aberration in the area with aberrations. Then, based on the deformation compensation amount of the corresponding area of ​​the optical device, a corresponding compensation control signal can be generated to control the corresponding compensation device to compensate the corresponding area of ​​the optical device with deformation. Therefore, the local deformation of the optical device can be accurately compensated, thereby improving the imaging quality of the optical device.

[0070] To enable those skilled in the art to better understand and implement the optical device deformation compensation method in the embodiments of this specification, the following detailed description is provided through specific examples and in conjunction with the accompanying drawings.

[0071] In practice, when it is determined that there is a difference between the actual pattern formed on the wafer surface and the preset pattern, since the difference is caused by the deformation of the optical device, the actual aberration in the aberration area can be converted into the deformation compensation amount of the corresponding area of ​​the optical device. By compensating for the deformation of the optical device, the imaging aberration on the wafer surface can be reduced, thereby improving the lithography quality.

[0072] In practical implementation, various methods can be used to obtain the deformation compensation amount for the corresponding region of the optical device. As a specific example, the actual aberrations in the region with aberrations can be expanded using a Zernike expansion to obtain the corresponding Zernike polynomials. Based on the aberrations of the Zernike constant terms corresponding to each order in the Zernike polynomials, the deformation compensation amount for the corresponding region of the optical device can be obtained.

[0073] Specifically, the Zernike constant aberration in the corresponding region of the optical device can be obtained based on the actual aberration in the region where the aberration exists, and the obtained Zernike constant aberration can be converted into the deformation compensation amount of the corresponding region of the optical device.

[0074] By converting the Zernike constant aberration into the deformation compensation amount of the corresponding region of the optical device, the difficulty of calculating the deformation compensation amount of the optical device can be reduced and the calculation efficiency can be improved.

[0075] Based on the Zernike constant aberration, the deformation compensation amount of the corresponding region of the optical device can be obtained. According to the deformation compensation amount of the corresponding region, the corresponding compensation device can be controlled to compensate the corresponding region of the optical device.

[0076] Reference Figure 4 The flowchart shown in this embodiment illustrates the compensation process for a specific application scenario of an optical device. Specifically, in this embodiment, the compensation for the corresponding area of ​​the optical device can be performed according to the following steps:

[0077] S41, based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, determine the compensation voltage of the compensation device at the corresponding position and generate a compensation voltage signal.

[0078] S42, output the compensation voltage signal to the compensation device at the corresponding position to compensate the corresponding area of ​​the optical device.

[0079] Specifically, since the compensation voltage signal is obtained based on the deformation compensation amount of the deformed area of ​​the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, when the compensation voltage signal is output to the compensation device, the compensation device performs precise compensation on the deformed area of ​​the optical device based on the compensation voltage signal.

[0080] As mentioned earlier, optical devices may deform due to high-power laser irradiation, leading to deviations in the final image formed on the wafer surface. Therefore, the shape of the optical devices can be corrected; that is, the deformed area of ​​the optical device can be specifically corrected to restore it to its original shape, thereby achieving a corresponding compensation effect, reducing imaging aberrations, and improving lithography accuracy.

[0081] In step S42, in a specific implementation, based on the compensation voltage signal, the compensation device can apply a force to the corresponding region (the deformed region) of the optical device to drive the optical device to move and compensate for the corresponding region of the optical device. Thus, by applying a force to the deformed region of the optical device, the deformed region can be driven to move, thereby locally and precisely correcting the shape of the optical device and achieving the corresponding compensation effect.

[0082] In practical applications, during photolithography, the wafer is located at the bottom, with optical components and a photomask arranged vertically on it. The inventors discovered that when using optical components to transfer the pattern from the photomask to the wafer, the imaging quality is better when the center of the photomask, the center of the optical component, and the center of the wafer are on the same horizontal line. Therefore, in some embodiments of this specification, when deformation is determined in a corresponding area of ​​the optical component, the compensation device can apply a force to the corresponding area of ​​the optical component in the direction perpendicular to the wafer surface, according to the compensation voltage signal, to drive the deformed area of ​​the optical component to move, compensating for the deformation of the corresponding area of ​​the optical component. The resulting actual focal plane is closer to the ideal spherical focal plane, thereby enabling the center of the photomask, the center of the optical component, and the center of the wafer to be on the same horizontal line.

[0083] In some other embodiments of this specification, the deformation of the corresponding region of the optical device can also be compensated by applying a force to the corresponding region of the optical device in a direction parallel to the wafer surface.

[0084] In summary, based on the calculated deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, the compensation voltage signal of the compensation device output to the corresponding position can be determined. The compensation device can perform compensation based on the compensation voltage signal of the corresponding region of the optical device, thereby reducing the impact of optical device deformation on imaging.

[0085] As mentioned above, the compensation device can drive the optical device to move according to the compensation voltage signal. When the moving distance of the optical device is equal to the deformation compensation amount of the corresponding area of ​​the optical device, it indicates that the compensation of the corresponding area of ​​the optical device has been completed.

[0086] In practice, due to the inertia of the compensation device during its movement, overcompensation may occur. To avoid overcompensation of the deformation area of ​​the optical device and further improve the compensation accuracy, in practice, the displacement of the corresponding area of ​​the optical device can be detected, and when it is determined that the displacement of the optical device is equal to the deformation of the corresponding area of ​​the optical device, the compensation control signal is stopped from being output to the compensation device at the corresponding position.

[0087] This specification also provides a deformation compensation system corresponding to the above-described optical device deformation compensation method. The following detailed description is provided with reference to the accompanying drawings and specific examples.

[0088] Reference Figure 5 The diagram shown is a structural schematic of an optical device deformation compensation system according to an embodiment of this specification, wherein the optical device is used to transfer a pattern on a photomask onto a wafer.

[0089] In some embodiments of this specification, the optical device deformation compensation system 50 includes an aberration acquisition device 51, a compensation control device 52, and a compensation device 53, wherein:

[0090] The aberration acquisition device 51 is adapted to determine the region in the actual pattern that contains aberrations based on the difference between the actual pattern formed on the wafer surface and the preset pattern.

[0091] The compensation control device 52 is adapted to obtain the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region where the aberration exists; and to generate a corresponding compensation control signal based on the deformation compensation amount of the corresponding region of the optical device.

[0092] The compensation device 53 is adapted to compensate the corresponding area of ​​the optical device according to the compensation control signal.

[0093] The following combination Figure 5 A brief introduction to the working principle of the optical device deformation compensation system 50:

[0094] The aberration acquisition device 51 can determine the region with aberration in the actual pattern formed on the wafer surface based on the difference between the actual pattern formed and the preset pattern. The compensation control device 52 calculates the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region with aberration. Based on the calculated deformation compensation amount of the corresponding region of the optical device, the compensation control device 52 generates a corresponding compensation control signal and outputs it to the compensation device 53. Under the control of the compensation control signal, the compensation device 53 can compensate the corresponding region of the optical device.

[0095] Using the aforementioned optical device deformation compensation system 50, since the aberration acquisition device 51 determines the region of the image where aberration exists, which can reflect the deformation of the corresponding region of the optical device, the compensation control device 52 can obtain the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region where aberration exists. Then, based on the deformation compensation amount of the corresponding region of the optical device, it can generate a corresponding compensation control signal and output it to the compensation device 53, controlling the corresponding compensation device 53 to compensate the corresponding region of the optical device where deformation exists. Therefore, it can accurately compensate for the local deformation of the optical device, thereby improving the imaging quality of the optical device.

[0096] In practice, when the aberration acquisition device determines that there is a difference between the actual pattern formed on the wafer surface and the preset pattern, since the difference is caused by the deformation of the optical device, the compensation control device can convert the actual aberration in the aberration area into the deformation compensation amount of the corresponding area of ​​the optical device. By compensating the area where the optical device is deformed, the imaging aberration on the wafer surface can be reduced, thereby improving the lithography accuracy.

[0097] In some examples of this specification, the aberration acquisition device may include a complementary metal-oxide-semiconductor (CMOS) image sensor.

[0098] In practical implementation, various methods can be used to obtain the deformation compensation amount for the corresponding region of the optical device. As a specific example, the compensation control device can perform a Zernike expansion on the actual aberrations in the aberration-affected region to obtain the corresponding Zernike polynomials, and then obtain the deformation compensation amount for the corresponding region of the optical device based on the aberrations of the Zernike constant terms corresponding to each order in the Zernike polynomials.

[0099] In some embodiments of this specification, reference continues to be made to... Figure 5 The compensation control device 52 may include a compensation amount calculation unit 521 and a compensation control unit 522, wherein:

[0100] The compensation calculation unit 521 is adapted to obtain the Zernike constant aberration in the corresponding region of the optical device based on the actual aberration in the region where the aberration exists, and to convert the obtained Zernike constant aberration into the deformation compensation amount of the corresponding region of the optical device.

[0101] The compensation control unit 522 is adapted to determine the compensation voltage of the compensation device at the corresponding position based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, and output the generated compensation voltage signal to the compensation device at the corresponding position.

[0102] In specific implementations, the compensation control device 52 can be implemented by a processing chip such as a central processing unit (CPU) or a field programmable gate array (FPGA), or by an application specific integrated circuit (ASIC) or one or more integrated circuits configured to implement the embodiments of the present invention.

[0103] By employing the aforementioned compensation control device, based on the actual aberrations in the region where aberrations exist, the Zernike constant aberrations in the corresponding region of the optical device can be obtained. By converting the Zernike constant aberrations into the deformation compensation amount of the corresponding region of the optical device, the difficulty of calculating the deformation compensation amount of the optical device can be reduced, and the calculation efficiency can be improved.

[0104] In a specific implementation, the compensation control unit can generate a corresponding compensation voltage signal based on the deformation compensation amount of the corresponding region, and control the corresponding compensation device to compensate the corresponding region of the optical device.

[0105] Since the compensation voltage signal is obtained based on the deformation compensation amount of the deformed region of the optical device, when the compensation voltage signal is output to the compensation device, it continues to refer to... Figure 5 The compensation device 53 is adapted to apply a force to the corresponding region (the deformed region) of the optical device according to the compensation voltage signal, so as to drive the optical device to move and compensate the corresponding region of the optical device.

[0106] Therefore, by applying force to the deformed area of ​​the optical device, the optical device can be driven to move, the shape of the optical device can be corrected, and compensation can be achieved for the corresponding area of ​​the optical device.

[0107] As an optional example, the compensation device 53 may include a piezoelectric ceramic actuator.

[0108] In summary, based on the calculated deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, the compensation control device can determine the compensation voltage signal of the compensation device at the corresponding position. The compensation device can perform compensation based on the compensation voltage signal of the corresponding region of the optical device (the region where deformation occurs), thereby reducing the impact of optical device deformation on imaging.

[0109] As mentioned above, the compensation device can drive the optical device to move according to the compensation voltage signal. When the moving distance of the optical device is equal to the deformation compensation amount of the corresponding area of ​​the optical device, it indicates that the compensation of the corresponding area of ​​the optical device has been completed.

[0110] In practical implementation, overcompensation may occur due to the inertia of the compensation device during its movement. To avoid overcompensation of the deformation area of ​​the optical components and further improve the compensation accuracy, in practical implementation, we will continue to refer to... Figure 5 The optical device deformation compensation system 50 may further include: a displacement detection device 54, adapted to detect the displacement of the corresponding area of ​​the optical device and output it to the compensation control device 52; correspondingly, the compensation control device 52 is also adapted to stop outputting the compensation voltage signal to the compensation device 53 at the corresponding position when it is determined that the displacement of the optical device is equal to the deformation compensation amount of the corresponding area of ​​the optical device, thereby completing the compensation of the deformed area of ​​the optical device.

[0111] As an optional example, the displacement detection device 54 may include a displacement sensor. As a specific example, the displacement sensor may specifically be a grating ruler displacement sensor.

[0112] In practical applications, during photolithography, the wafer is located at the bottom, with optical components and a photomask arranged vertically on it. The inventors discovered that when using optical components to transfer the pattern from the photomask to the wafer, the imaging quality is better when the center of the photomask, the center of the optical component, and the center of the wafer are on the same horizontal line. Therefore, in some embodiments of this specification, when deformation is determined in a corresponding area of ​​the optical component, the compensation device can apply a force to the corresponding area of ​​the optical component in the direction perpendicular to the wafer surface, based on the compensation voltage signal, to drive the optical component to move and compensate for the deformation of the corresponding area of ​​the optical component. The resulting actual focal plane is closer to the ideal spherical focal plane, thereby enabling the center of the photomask, the center of the optical component, and the center of the wafer to be on the same horizontal line. Correspondingly, the displacement detection device can detect the displacement of the optical component.

[0113] In some embodiments of this specification, to compensate for the deformation of the optical device in the direction perpendicular to the wafer surface, multiple piezoelectric ceramic actuators and multiple displacement sensors can be respectively arranged on opposite sides of the optical device in the direction perpendicular to the wafer surface, and the positions of the multiple piezoelectric ceramic actuators and the multiple displacement sensors correspond one-to-one.

[0114] To enable those skilled in the art to better understand and implement the optical device deformation compensation schemes in the embodiments of this specification, the following description uses a specific application scenario as an example.

[0115] Reference Figure 6 The diagram shown is a structural schematic of an optical device deformation compensation system in a specific application scenario of an embodiment of this specification. Figure 6 As shown, the optical device deformation compensation system 60 is adapted to compensate for the area where the optical device 6A is deformed. The optical device deformation compensation system 60 may include an aberration acquisition device. Figure 6 (not shown), compensation control device ( Figure 6 (Not shown), and includes multiple piezoelectric ceramic actuators 61 and multiple displacement sensors 62 respectively disposed on opposite sides of the optical device 6A in the direction perpendicular to the wafer surface, and the positions of the multiple piezoelectric ceramic actuators 61 and multiple displacement sensors 62 correspond one-to-one.

[0116] In some embodiments of this specification, when the aberration acquisition device determines the region with aberration in the actually formed pattern based on the difference between the actual pattern formed on the wafer surface and the preset pattern, the compensation control device can obtain the Zernike constant aberration in the corresponding region of the optical device based on the actual aberration in the region with aberration, and convert the obtained Zernike constant aberration into the deformation compensation amount of the corresponding region of the optical device 6A; and generate a corresponding compensation voltage signal to the piezoelectric ceramic actuator 61 at the corresponding position based on the deformation compensation amount of the corresponding region of the optical device 6A and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage. Under the action of the compensation voltage signal, the piezoelectric ceramic actuator 61 can extend and retract. When the voltage value of the compensation voltage signal changes in a positive direction (from small to large), the piezoelectric ceramic actuator 61 can extend, driving the optical device 6A to move in the direction shown by arrow A; when the voltage value of the compensation voltage signal changes in a negative direction (from large to small), the piezoelectric ceramic actuator 61 can retract, driving the optical device 6A to move in the opposite direction to arrow A.

[0117] When the piezoelectric ceramic actuator 61 drives the optical device 6A to move up and down in the direction indicated by arrow A, the displacement sensor 62 corresponding to the piezoelectric ceramic actuator 61 can detect the displacement of the optical device 6A and output it to the compensation control device. When the compensation control device determines that the displacement of the optical device 6A is the same as the calculated deformation compensation amount, it stops outputting the compensation voltage signal to the piezoelectric ceramic actuator 61 at the corresponding position and stops compensating for the deformation of the optical device 6A.

[0118] It should be noted that the distribution of the displacement sensor and piezoelectric ceramic actuator on the optical device described above is only an illustrative example. In actual implementation, the displacement sensor and piezoelectric ceramic actuator can be placed in areas of the optical device that are prone to deformation.

[0119] This specification also provides a lithography machine in some embodiments, such as... Figure 7 As shown, the lithography machine 70 may include: optical components 71 and an optical component deformation compensation system 72, wherein:

[0120] The optical device 71 is adapted to transfer a pattern on a mask onto a wafer;

[0121] The optical device deformation compensation system 72 is adapted to compensate for the deformation of the optical device.

[0122] The optical device deformation compensation system 72 can adopt the scheme shown in any of the foregoing embodiments, and the specific details can be found in the foregoing embodiments, which will not be described in detail here.

[0123] When using optical device 71 to transfer the pattern on the photomask to the wafer surface, optical device deformation compensation system 72 can determine the deformation compensation amount of the corresponding area of ​​optical device 71 based on the difference between the actual pattern formed on the wafer surface and the preset pattern. Based on the determined deformation compensation amount of the corresponding area, it drives optical device 71 to move. When it is determined that the displacement of the optical device is equal to the deformation of the corresponding area of ​​the optical device, it stops outputting the compensation control signal to the compensation device at the corresponding position, thus completing the compensation of the deformation area of ​​optical device 71.

[0124] In some embodiments of this specification, the optical element 71 may be a lens. A lithography machine 70 with an optical element deformation compensation system 72 can compensate for the deformation caused by the lens, thereby improving the imaging quality of the lithography machine.

[0125] While the embodiments disclosed in this specification are as described above, the invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this invention; therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. A method for compensating for deformation of an optical device, wherein, Optical devices are used to transfer patterns from a photomask onto a wafer, characterized in that the method comprises: Based on the difference between the actual pattern formed on the wafer surface and the preset pattern, the regions in the actual pattern that contain aberrations are determined; Based on the actual aberration in the region where aberration exists, the deformation compensation amount for the corresponding region of the optical device is obtained; Based on the deformation compensation amount of the corresponding region of the optical device, a corresponding compensation control signal is generated to control the corresponding compensation device to compensate the corresponding region of the optical device, including: Based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, the compensation voltage of the compensation device at the corresponding position is determined, and a compensation voltage signal is generated. According to the compensation voltage signal, the compensation device applies a force to the corresponding area of ​​the optical device to drive the optical device to move and compensate the corresponding area of ​​the optical device; The displacement of the corresponding region of the optical device is detected, and when it is determined that the displacement of the optical device is equal to the deformation of the corresponding region of the optical device, the output of the compensation control signal to the compensation device at the corresponding position is stopped. The compensation device corrects the shape of the optical device so that the optical device can be restored to its original state. The compensation device compensates for the deformation of the optical device in multiple different directions; The compensation device applies a force to a corresponding area of ​​the optical device to drive the optical device to move, including: by applying a force to the deformed area of ​​the optical device, the deformed area of ​​the optical device can be driven to move, thereby making local precise correction to the shape of the optical device.

2. The optical device deformation compensation method according to claim 1, characterized in that, The step of obtaining the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region where aberration exists includes: Based on the actual aberrations in the aberration-affected regions, the Zernike constant aberrations present in the corresponding regions of the optical device are obtained; The obtained Zernike constant aberration is converted into the deformation compensation amount of the corresponding region of the optical device.

3. The optical device deformation compensation method according to claim 1, characterized in that, The step of applying force to a corresponding region of the optical device based on the compensation voltage signal to drive the optical device to move and compensate the corresponding region of the optical device includes: According to the compensation voltage signal, the compensation device applies a force to the corresponding area of ​​the optical device in the direction perpendicular to the wafer surface to drive the optical device to move and compensate for the deformation of the corresponding area of ​​the optical device.

4. An optical device deformation compensation system, wherein, Optical devices are used to transfer patterns from a photomask onto a wafer, characterized in that the deformation compensation system includes an aberration acquisition device, a compensation control device, and a compensation device, wherein: The aberration acquisition device is adapted to determine the region in the actually formed pattern that contains aberrations based on the difference between the actual pattern formed on the wafer surface and the preset pattern. The compensation control device is adapted to obtain the deformation compensation amount of the corresponding region of the optical device based on the actual aberration in the region where the aberration exists; and to generate a corresponding compensation control signal based on the deformation compensation amount of the corresponding region of the optical device. The compensation device is adapted to compensate the corresponding area of ​​the optical device according to the compensation control signal; The compensation device compensates for the deformation of the optical device in multiple different directions. The compensation device applies a force to a corresponding area of ​​the optical device to drive the optical device to move, including: by applying a force to the deformed area of ​​the optical device, the deformed area of ​​the optical device can be driven to move, thereby making local precise correction to the shape of the optical device; The compensation device corrects the shape of the optical device, enabling it to return to its original state. The compensation control device includes a compensation control unit, which is adapted to determine the compensation voltage of the compensation device at the corresponding position based on the deformation compensation amount of the corresponding region of the optical device and the pre-stored mapping relationship between the deformation compensation amount and the compensation voltage, and output the generated compensation voltage signal to the compensation device at the corresponding position. The compensation device is adapted to apply force to the corresponding area of ​​the optical device according to the compensation voltage signal, so as to drive the optical device to move and compensate the corresponding area of ​​the optical device. The deformation compensation system also includes: A displacement detection device is adapted to detect the displacement of the corresponding area of ​​the optical device and output it to the compensation control device; The compensation control device is further adapted to stop outputting the compensation voltage signal to the compensation device at the corresponding position when it is determined that the displacement of the optical device is equal to the deformation compensation of the corresponding region of the optical device.

5. The optical device deformation compensation system according to claim 4, characterized in that, The compensation control device includes a compensation amount calculation unit, wherein: The compensation calculation unit is adapted to obtain the Zernike constant aberration in the corresponding region of the optical device based on the actual aberration in the region where the aberration exists, and to convert the obtained Zernike constant aberration into the deformation compensation amount of the corresponding region of the optical device.

6. The optical device deformation compensation system according to claim 4, characterized in that, The compensation device includes a piezoelectric ceramic actuator, and the displacement detection device includes a displacement sensor; Multiple piezoelectric ceramic actuators and multiple displacement sensors are respectively arranged on opposite sides of the optical device in the direction perpendicular to the wafer surface, and the positions of the multiple piezoelectric ceramic actuators and the multiple displacement sensors correspond one-to-one.

7. A lithography machine, characterized in that, include: Optical devices suitable for transferring patterns from a photomask onto a wafer; The optical device deformation compensation system according to any one of claims 4-6 is suitable for compensating for the deformation of the optical device.

8. The lithography machine according to claim 7, characterized in that, The optical device is a lens.

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