Objective lens damping device and damping method for objective lens of photoetching machine

Abstract

The embodiment of the invention provides an objective lens vibration reduction device and a vibration reduction method for a photoetching machine objective lens, and the objective lens vibration reduction device comprises an objective lens damper, the interior of the objective lens damper adopts a flexible hinge structure, and the flexible hinge structure provides elastic support when external vibration or temperature changes so as to buffer vibration transmission and reduce stress caused by a thermal expansion effect; the objective lens damper comprises an upper layer, a middle layer and a lower layer. The upper layer is an objective lens contact end and is provided with an interface connected with an objective lens; the lower layer is a frame contact end and is provided with an interface connected with a frame; the middle layer is of a flexible hinge structure, necessary flexible supporting is provided, and therefore vibration isolation and thermal stress buffering are achieved. Through the flexible hinge structure, an efficient objective lens vibration reduction scheme is provided, vibration transmission can be effectively reduced, thermal expansion stress can be relieved, and the optical stability of the photoetching machine can be improved. Through accurate simulation calculation and optimized structural design, high performance and high reliability of the objective lens damper are ensured, and the objective lens damper has a wide application prospect in the field of semiconductor manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of lithography machines, and in particular, to an objective lens vibration damping device and a vibration damping method for a lithography machine objective lens. Background Art

[0002] The objective lens of a lithography machine plays a crucial role in the lithography process. Its main function is to project the fine patterns on the mask plate onto the photoresist layer on the surface of the silicon wafer with high precision. As one of the core optical components of the lithography machine, the performance of the objective lens directly affects the resolution, accuracy, and uniformity of the lithography pattern. Therefore, strict requirements are imposed on its installation and stability.

[0003] In the prior art, the objective lens is usually fixed to the whole machine frame by means of screw assembly to ensure its position stability in a rigid connection manner. However, this installation method has the following deficiencies: First, as a high-precision optical component, the objective lens is extremely sensitive to external vibrations. Since the rigid connection method will directly transmit the vibrations on the frame to the objective lens, it may lead to a decrease in the accuracy of the lithography pattern and even affect the overall lithography effect.

[0004] Second, the objective lens and the machine frame are usually made of different materials, and there are significant differences in their thermal expansion coefficients. When the ambient temperature changes, the thermal expansion mismatch between the two may cause additional internal stresses, thereby affecting the optical performance and stability of the objective lens.

[0005] Therefore, there is an urgent need for a new objective lens vibration damping device and method to solve the above problems. Summary of the Invention

[0006] The purpose of this application is to solve the problem that in the prior art, the objective lens is usually fixed to the whole machine frame by means of screw assembly, which is easily affected by external vibrations and changes in ambient temperature, resulting in poor optical performance and stability of the objective lens. Therefore, this application provides an objective lens vibration damping device and a vibration damping method for a lithography machine objective lens, which can effectively damp vibrations, relieve thermal stress, and improve lithography accuracy and system stability.

[0007] An embodiment of this application provides an objective lens vibration damping device, including: An objective lens damper, the inside of which adopts a flexible hinge structure. The flexible hinge structure provides elastic support when there are external vibrations or temperature changes to buffer the vibration transmission and reduce the stress caused by the thermal expansion effect; An objective lens damper, including: an upper layer, a middle layer, and a lower layer; The upper layer is the objective lens contact end, provided with an interface for connecting to the objective lens; The lower layer is the frame contact end, provided with an interface for connecting to the frame; The middle layer adopts a flexible hinge structure to provide necessary flexible support for vibration isolation and thermal stress buffering.

[0008] In some embodiments, the objective lens is flexibly connected to the frame through an objective lens damper.

[0009] In some embodiments, the middle layer of the objective lens damper is connected to the upper layer and the lower layer through flexible hinges to provide flexible support in the vertical, radial, and tangential directions.

[0010] In some embodiments, the flexible hinges in the objective lens damper are arranged in a centrosymmetric layout so that the stress is evenly distributed in all directions of the flexible hinges.

[0011] In some embodiments, flexible hinges are evenly arranged at four symmetric positions.

[0012] In some embodiments, the thickness of the flexible hinge is determined according to simulation calculations.

[0013] In some embodiments, the thickness of the flexible hinge is between 1 - 5 mm.

[0014] The embodiments of the present application also provide a vibration damping method for a lithography machine objective lens, including: Designing an objective lens damper to adopt a flexible hinge structure; Determining the thickness of the flexible hinge through simulation calculations to optimize the stiffness of the damper; Setting an objective lens interface on the upper layer of the objective lens damper and a frame interface on the lower layer to achieve the installation and connection of the objective lens and the frame; Realizing the flexible connection between the objective lens and the frame through the elastic deformation of the flexible hinge.

[0015] In some embodiments, the thickness of the flexible hinge is determined by simulation calculations, and different thicknesses correspond to different stiffnesses.

[0016] In some embodiments, constraints are applied to the bottom surface of the flexible block where the flexible hinge is located, and loads are respectively applied to the upper contact surfaces of the flexible blocks to which the flexible hinges belong. According to the simulation results, the deformation amounts in the radial, tangential, and vertical directions are measured, and according to the stiffness calculation formula

[0017] Calculate the stiffness of the flexible block in the radial, tangential, and vertical directions, where K represents stiffness, F represents the applied load, and Δ represents the deformation amount.

[0018] In some embodiments, the thickness is optimized so that the stiffness is less than 1×10 7 N / m.

[0019] In the embodiments of the present application, a flexible hinge structure is used to absorb and attenuate external vibrations, effectively reducing the interference on the objective lens and improving the lithography accuracy; the flexible hinge can produce elastic deformation with temperature changes, reducing the internal stress caused by the difference in thermal expansion coefficients and improving the system stability; simulation calculations are used to optimize the thickness and stiffness of the flexible hinge, making the stiffness of the objective lens controllable in different directions and meeting the requirements of high-precision lithography machines; mechanical design is used to achieve passive vibration damping, without the need for additional energy input and being easily compatible with existing lithography machine systems. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the objective lens vibration damping device according to the embodiments of the present application; Figure 2 It is a schematic cross-sectional structural diagram of the objective lens vibration damping device according to the embodiments of the present application; Description of the Reference Numerals: 1, upper layer of the damper; 2, middle layer of the damper; 3, lower layer of the damper; 4, objective lens interface; 5, frame interface. Detailed Embodiments

[0021] The following specific embodiments illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Although the description of the present application will be introduced in combination with some embodiments, this does not mean that the features of this application are limited to this implementation manner. On the contrary, the purpose of introducing the application in combination with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without these details. In addition, in order to avoid confusing or obscuring the key points of the present application, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0022] It should be noted that in this specification, similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0023] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0024] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0025] In the description of the present application, it should be understood that "electrically connected" in the present application can be understood as physical contact and electrical conduction between components; it can also be understood as a form of connection between different components in a circuit structure through physical lines such as copper foils or wires of a printed circuit board (PCB) that can transmit electrical signals. "Coupled through..." can be understood as electrical conduction through indirect coupling. Indirect coupling can be understood as non-contact coupling. Among them, those skilled in the art can understand that the coupling phenomenon refers to the phenomenon that there is a close cooperation and mutual influence between the inputs and outputs of two or more circuit elements or electrical networks, and energy is transmitted from one side to the other through mutual interaction. To make the purpose, technical solutions, and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0026] A lithography machine is a key device used in semiconductor manufacturing. Its core function is to accurately replicate the fine patterns on a mask plate on the photoresist layer of a silicon wafer. Among them, as the core optical component of the lithography machine, the performance of the objective lens directly determines the accuracy, uniformity of the lithography pattern, and the quality of the overall lithography process. Therefore, extremely high requirements are put forward for the installation method and its stability of the objective lens.

[0027] In the prior art, the objective lens is usually fixed on the machine frame by means of screw assembly, and its position is ensured to be stable through rigid connection. However, this installation method has the following technical problems: First, as a high-precision optical component, the objective lens is extremely sensitive to external vibrations. Due to the characteristics of rigid connection, the vibrations on the frame will be directly transmitted to the objective lens, thereby affecting the lithography accuracy and even resulting in a decline in imaging quality. Second, the objective lens and the frame are usually made of different materials, and there are significant differences in their thermal expansion coefficients. In the case of environmental temperature changes, the thermal expansion mismatch between the two may lead to large internal stresses, thereby affecting the optical performance and stability of the objective lens.

[0028] In view of the above problems, there is an urgent need to provide an improved objective lens vibration damping device and installation method to effectively reduce the impact of vibrations on the objective lens, reduce the internal stresses generated due to temperature changes, and ensure the stability and lithography accuracy of the objective lens of the lithography machine.

[0029] Figure 1 FIG. is a schematic structural diagram of the objective lens vibration damping device according to an embodiment of the present application. Figure 2 FIG. is a schematic cross-sectional structural diagram of the objective lens vibration damping device according to an embodiment of the present application. As Figure 1 and Figure 2 shown, the embodiment of the present application provides an objective lens vibration damping device, including: an objective lens damper, the inside of the objective lens damper adopts a flexible hinge structure, and the flexible hinge structure provides elastic support when there is external vibration or temperature change to buffer the vibration transmission and reduce the stress caused by the thermal expansion effect.

[0030] The present application designs an objective lens damper with a flexible hinge structure, which effectively reduces the vibration impact and alleviates the thermal expansion stress while ensuring the installation stability of the objective lens, and improves the imaging accuracy and stability of the lithography machine.

[0031] Specifically, as Figure 1 The objective lens damper includes: an upper layer 1, a middle layer 2, and a lower layer 3; the upper layer 1 is the objective lens contact end and is provided with an interface for connecting with the objective lens; the lower layer 2 is the frame contact end and is provided with an interface for connecting with the frame; the middle layer 2 adopts a flexible hinge structure to provide necessary flexible support to achieve vibration isolation and thermal stress buffering.

[0032] Among them, the objective lens damper adopts a flexible hinge structure, and the flexible hinge structure can generate small elastic deformations when there is external vibration or temperature change to reduce the stress impact on the objective lens. The objective lens damper adopts a multi-layer distribution structure, including an upper layer 1, a middle layer 2, and a lower layer 3, where: the upper layer 1 (objective lens contact end): is used for fixedly connecting with the objective lens and ensuring the precise alignment of the optical system; the middle layer 2 (flexible hinge structure): provides necessary flexible support to achieve vibration isolation and thermal stress buffering; the lower layer 3 (frame contact end): is used for connecting with the lithography machine frame and providing overall structural support.

[0033] Among them, the middle layer 2 of the objective lens damper is connected to the upper layer 1 and the lower layer 3 through flexible hinges to provide flexible support in the vertical direction, radial direction, and tangential direction. The internal of the objective lens damper adopts the form of flexible hinges, which can provide elastic force in each degree of freedom of motion.

[0034] In the embodiment of the present application, the flexible hinges in the objective lens damper are centrosymmetrically arranged so that the stress of the flexible hinges is evenly distributed in all directions, avoiding out-of-control deformation caused by excessive force in a single direction. Exemplarily, Figure 2 What is shown in [figure] is a quarter structure of the objective lens damper, and flexible hinges can be evenly arranged at four symmetric positions to ensure the stability of the entire objective lens damper.

[0035] Furthermore, the objective lens is flexibly connected to the frame through the objective lens damper. By adopting a non-rigid connection method, the objective lens is flexibly connected to the frame through the objective lens damper, avoiding the direct transmission of vibration caused by rigid connection. Threaded or card slot structures are respectively provided on the upper layer 1 and the lower layer 3 to facilitate installation and disassembly, and at the same time ensure that loosening or displacement will not occur during long-term use.

[0036] As Figure 2 shown, the upper layer 1 and the lower layer 3 of the objective lens damper are respectively provided with an objective lens interface 4 and a frame interface 5, so that the objective lens damper can be installed between the objective lens and the frame, and thus flexible connection can be achieved through the stretchability of the flexible hinges themselves, achieving a better protection effect on the objective lens. The designed objective lens damper belongs to passive vibration reduction, which can be easily realized only through mechanical design, and can preferably achieve vibration isolation and thermal decoupling.

[0037] Furthermore, the middle layer 2 of the objective lens damper is a flexible hinge structure, and the vibration and thermal expansion are alleviated through the flexibility of the flexible hinges themselves to ensure a relatively small vertical stiffness.

[0038] Even further, the thickness of the flexible hinges is determined according to simulation calculations. The thickness of the flexible hinges of the objective lens damper is determined by simulation calculations. Different stiffnesses are calculated according to different thicknesses, and the thickness of the selected flexible hinges is determined through simulation methods, thereby ensuring the rationality of the design and the vibration reduction effect.

[0039] In the embodiment of the present application, the thickness of the flexible hinges is between 1 - 5 mm. The thickness of the flexible hinges is determined by simulation calculations, and the stiffness is calculated through K = F / Δ, where F represents the applied load and Δ represents the deformation amount, to ensure that the stiffness of the flexible blocks where the flexible hinges are located is less than 1×10 7 N / m.

[0040] In this application, the objective lens damper achieves passive vibration reduction through mechanical design without the need for additional external energy input, thereby improving the reliability and stability of the system. The middle-layer flexible hinge structure is adopted, and the thickness of the flexible hinge is optimized through simulation to ensure that it can provide sufficient flexible buffering while maintaining the required stiffness. This design reduces the influence of vibration transmission and thermal stress without affecting the optical accuracy, thereby improving the stability and service life of the lithography machine objective lens.

[0041] The embodiment of this application also provides a vibration reduction method for a lithography machine objective lens, including: designing an objective lens damper to adopt a flexible hinge structure; determining the thickness of the flexible hinge through simulation calculation to optimize the stiffness of the damper; setting an objective lens interface on the upper layer of the objective lens damper and a frame interface on the lower layer to realize the installation and connection of the objective lens and the frame; and realizing the flexible connection between the objective lens and the frame through the elastic deformation of the flexible hinge.

[0042] Among them, the thickness of the flexible hinge is determined by simulation calculation. Different thicknesses correspond to different stiffnesses. By optimizing the thickness, the obtained stiffness meets the design requirements, thereby determining the thickness of the flexible hinge.

[0043] Specifically, constraints are applied to the bottom surface of the flexible block where the flexible hinge is located, and loads are respectively applied to the upper contact surfaces of the flexible blocks to which the flexible hinge belongs. According to the simulation results, the deformation amounts in the radial, tangential, and vertical directions are measured, and according to the stiffness calculation formula (1) (1) Calculate the stiffnesses of the flexible block in the radial, tangential, and vertical directions, where K represents stiffness, F represents the applied load, and Δ represents the deformation amount.

[0044] The relationship between the flexible block, the bottom surface of the flexible block, and the flexible hinge will be described below.

[0045] The flexible block is a part of the entire objective lens damper and usually includes a flexible hinge structure. Its bottom surface (i.e., the bottom surface of the flexible block) is usually used for fixing or constraining to ensure that the entire flexible block is restricted in certain directions for testing or optimizing the stiffness parameters.

[0046] The bottom surface of the flexible block is the fixed or constrained part of the entire damping structure, while the flexible hinge is the core vibration reduction component of the flexible block. The bottom surface of the flexible block provides a fixed reference, and the flexible hinge determines the flexible stiffness of the system. During stiffness calculation, the bottom surface of the flexible block is constrained, and the elastic deformation of the flexible hinge is measured to optimize the vibration reduction effect. This design helps to improve the stability of the lithography machine objective lens while reducing vibration effects and thermal stress problems.

[0047] In the embodiments of the present application, the elastic deformation of the flexible hinge is used to absorb and attenuate vibrations, preventing the vibrations of the frame from being directly transmitted to the objective lens. The flexible hinge can adapt to the expansion or contraction caused by temperature changes, reducing the internal stress generated between the objective lens and the frame due to different thermal expansion coefficients. Appropriate flexibility is provided in the vertical (Z-direction), radial (X / Y-direction), and tangential (rotation direction) directions, enabling the objective lens to maintain stability while not being affected by rigid constraints.

[0048] Furthermore, the thickness of the flexible hinge is optimized so that the stiffness is less than 1×10 7 N / m, ensuring that the vibration attenuation ability and thermal expansion compensation ability of the objective lens damper reach the best. The thickness is adjusted through simulation to make the stiffness appropriate, which can not only effectively reduce vibrations but also maintain the high-precision stability of the optical system.

[0049] In the embodiments of the application, a simulation calculation method is used to determine the thickness of the flexible hinge to ensure that its stiffness in different directions meets the design requirements.

[0050] In the embodiments of the present application, the flexible hinge structure is used to absorb and attenuate external vibrations, effectively reducing the interference received by the objective lens and improving the lithography accuracy; the flexible hinge can produce elastic deformation with temperature changes, reducing the internal stress caused by differences in thermal expansion coefficients and improving the system stability; the thickness and stiffness of the flexible hinge are optimized through simulation calculations, making the stiffness of the objective lens controllable in different directions and meeting the requirements of high-precision lithography machines; mechanical design is used to achieve passive vibration reduction, without the need for additional energy input and being easily compatible with existing lithography machine systems.

[0051] In an alternative practical approach, the optimal thickness and width of the flexible hinge are calculated through finite element analysis (FEA) to ensure the best vibration attenuation effect while maintaining structural stability.

[0052] The present application provides an objective lens vibration damping device and a vibration damping method for a lithography machine objective lens. Through the flexible hinge structure, an efficient objective lens vibration damping solution is provided, which can effectively reduce vibration transmission, relieve thermal expansion stress, and improve the optical stability of the lithography machine. Through precise simulation calculations and optimized structural designs, the high performance and high reliability of the objective lens damper are ensured, and it has broad application prospects in the field of semiconductor manufacturing.

[0053] Obviously, those skilled in the art can make various changes and deformations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and deformations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these changes and deformations.

Claims

1. An objective lens vibration reduction device, characterized in that: include: An objective lens damper, wherein a flexible hinge structure is used inside the objective lens damper, and the flexible hinge structure provides elastic support when there is external vibration or temperature change, so as to buffer vibration transmission and reduce stress caused by thermal expansion effect; The objective lens damper comprises: an upper layer, a middle layer and a lower layer; The upper layer is the objective lens contact end, which is provided with an interface for connecting with the objective lens; The lower layer is the frame contact end, which is provided with an interface for connecting with the frame; The middle layer adopts a flexible hinge structure to provide the necessary flexible support to achieve vibration isolation and thermal stress buffering; The middle layer of the objective lens damper is connected to the upper layer and the lower layer through a flexible hinge to provide flexible support in the vertical, radial and tangential directions; The thickness of the flexible hinge is determined according to simulation calculations.

2. The objective lens vibration reduction device according to claim 1, characterized in that: The objective lens is flexibly connected to the frame through the objective lens damper.

3. The objective lens vibration reduction device according to claim 1, characterized in that: The flexible hinges in the objective lens damper are arranged in a central symmetrical manner so that the stress of the flexible hinges in all directions is evenly distributed.

4. The objective lens vibration reduction device according to claim 3, characterized in that: The flexible hinges are evenly arranged at four symmetrical positions.

5. The objective lens vibration reduction device according to claim 1, characterized in that: The thickness of the flexible hinge is between 1-5 mm.

6. A vibration reduction method for a photolithography machine objective lens, characterized in that: include: The objective lens damper is designed to adopt a flexible hinge structure; The thickness of the flexible hinge is determined through simulation calculation to optimize the stiffness of the damper; An objective lens interface is arranged on the upper layer of the objective lens damper, and a frame interface is arranged on the lower layer to realize the installation connection between the objective lens and the frame; The flexible connection between the objective lens and the frame is achieved through the elastic deformation of the flexible hinge.

7. The vibration reduction method for a photolithography machine objective lens according to claim 6, characterized in that: The thickness of the flexible hinge is determined by simulation calculation, and different thicknesses correspond to different stiffnesses.

8. The vibration reduction method for a photolithography machine objective lens according to claim 6, characterized in that: Constraints are imposed on the bottom surface of the flexible block where the flexible hinge is located, and loads are applied to the upper contact surface of the flexible block to which the flexible hinge belongs. Based on the simulation results, the deformations in the radial, tangential and vertical directions are measured, and the stiffness calculation formula is used to calculate the deformations. The stiffness of the flexible block in radial, tangential and vertical directions is calculated, where K represents stiffness, F represents applied load, and Δ represents deformation.

9. The vibration reduction method for a photolithography machine objective lens according to claim 8, characterized in that: The thickness is optimized so that the stiffness is less than 1×10 7 N / m.

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