Objective lens damping device

Abstract

The embodiment of the utility model provides an objective lens damping device which comprises an objective lens damper, a flexible hinge structure is adopted in the objective lens damper, 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 upper layer of the objective lens damper is an objective lens contact end; 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. According to the utility model, the objective lens damper is arranged between the objective lens and the frame, so that the objective lens and the frame are flexibly connected through the scalability of the flexible hinge instead of being rigidly connected through a screw, a better protection effect on the objective lens is achieved, and the designed objective lens damper belongs to passive vibration reduction, so that the service life of the objective lens damper is prolonged. Only through mechanical design, the vibration isolator is easy to achieve, and vibration isolation and thermal decoupling are well achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of photoetching machine especially relates to an objective lens damping device. BACKGROUND

[0002] The objective lens of photoetching machine plays a vital role in photoetching process, and its main function is to project the fine pattern on the mask to the photoresist layer on the silicon wafer surface with high precision. As one of the core optical components of the photoetching machine, the performance of the objective lens directly affects the resolution, accuracy and uniformity of the photoetching pattern, so the installation and stability thereof are extremely strict.

[0003] In the prior art, the objective lens is usually fixed to the whole machine frame by screw assembly to ensure its position stability in a rigid connection mode. However, the installation mode has the following disadvantages:

[0004] Firstly, the objective lens is a high-precision optical element, which is extremely sensitive to external vibration. Since the rigid connection mode can directly transmit the vibration on the frame to the objective lens, it may cause the accuracy of the photoetching pattern to decrease, and even affect the overall photoetching effect.

[0005] Secondly, the objective lens and the frame are usually made of different materials, and there is a large difference in their thermal expansion coefficients. When the ambient temperature changes, the thermal expansion mismatch between them may cause additional internal stress, thereby affecting the optical performance and stability of the objective lens.

[0006] Therefore, there is an urgent need for a new objective lens damping device to solve the above problems. INVENTION CONTENTS

[0007] The utility model discloses a kind of objective lens damping devices, which can effectively reduce vibration, relieve thermal stress, improve photoetching precision and system stability.

[0008] The embodiment of the present application provides an objective lens damping device, comprising:

[0009] The objective lens damper is internally provided with a flexible hinge structure, which provides elastic support when external vibration or temperature changes to buffer vibration transmission and reduce stress caused by thermal expansion effect;

[0010] The objective lens damper comprises an upper layer, a middle layer and a lower layer.

[0011] The upper layer is an objective lens contact end, and an interface for connecting with the objective lens is arranged.

[0012] The lower layer is a frame contact end, and an interface for connecting with the frame is arranged;

[0013] The middle layer adopts a flexible hinge structure to provide necessary flexible support to realize vibration isolation and thermal stress buffering.

[0014] In some embodiments, the objective lens is flexibly connected with the frame through an objective lens damper.

[0015] In some embodiments, the middle layer of the objective lens damper is connected with the upper layer and the lower layer through a flexible hinge to provide flexible support in the vertical, radial and tangential directions.

[0016] In some embodiments, the flexible hinges in the objective lens damper are arranged in a central symmetric manner to uniformly distribute the stress of the flexible hinges in various directions.

[0017] In some embodiments, the flexible hinges are uniformly arranged at four symmetric positions.

[0018] In some embodiments, the thickness of the flexible hinges is determined according to simulation calculation.

[0019] In some embodiments, the thickness of the flexible hinges is between 1-5mm.

[0020] In some embodiments, the stiffness of the flexible hinges in various degrees of freedom is less than 1×10 N / m

[0021] In the embodiments of the present application, external vibration is absorbed and attenuated through the flexible hinge structure, effectively reducing the interference on the objective lens and improving the lithography precision; the flexible hinge can produce elastic deformation with temperature change, reducing the internal stress caused by the difference in thermal expansion coefficient and improving the system stability; the thickness and stiffness of the flexible hinge are optimized through simulation calculation, so that the stiffness of the objective lens in different directions is controllable, meeting the requirements of high-precision lithography machines; passive vibration reduction is realized through mechanical design, without the need for additional energy input, and it is easy to be compatible with existing lithography machine systems. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a structural schematic diagram of an objective lens damping device according to an embodiment of the present application;

[0023] Figure 2 FIG. 1 is a structural schematic diagram of an objective lens damping device according to an embodiment of the present application;

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1, upper layer of damper; 2, middle layer of damper; 3, lower layer of damper; 4, objective lens interface; 5, frame interface. DETAILED DESCRIPTION

[0026] The following detailed description together with the accompanying drawings makes apparent to those skilled in the art how the application can be practiced and will disclose the best mode of practicing the application. Although the description will describe the application in connection with some embodiments, it will be understood that the application is not limited to these embodiments specifically. On the contrary, the application is intended to cover all alternatives, modifications, and equivalents fair falling within the scope of the application as defined by the appended claims. To provide an overall understanding of the application, numerous specific details are set forth in the following description. The application can be practiced without some or all of these specific details. In some instances, well-known structures have not been described in detail in order not to obscure the understanding of this application. In addition, for the purpose of clarity, details describing some embodiments of the application will refer only to well-known concepts in order to avoid obscuring the conceptual understanding of the application. It should be noted that the embodiments and features of the application can be combined with each other, if not in contradiction.

[0027] It should be noted that in this specification and the like, the same or similar components are denoted by the same reference numerals, and the description will be given only once and not be repeated. It should be noted that in this specification and the like, similar reference numerals and characters denote similar items, and once an item is defined in one drawing, it is not necessary to further define and explain it in subsequent drawings.

[0028] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0030] In the description of the present application, it should be understood that in the present application, "electrical connection" can be understood as physical contact and electrical conduction of components; it can also be understood as the form of connection between different components in the circuit structure through the entity line of the printed circuit board (PCB) copper foil or wire which can transmit electrical signals. "Coupled by" can be understood as electrical conduction in space by indirect coupling. Indirect coupling can be understood as contactless coupling, wherein those skilled in the art can understand that the coupling phenomenon means that there is close cooperation and mutual influence between the input and output of two or more circuit components or electrical networks, and energy is transmitted from one side to the other side through interaction. In order to make the purpose, technical scheme 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.

[0031] The lithography machine is a key equipment for semiconductor manufacturing, and its core function is to accurately copy the fine pattern on the mask onto the photoresist layer on the silicon wafer. Among them, the objective lens as the core optical component of the lithography machine, its performance directly determines the precision, uniformity and overall lithography process quality of the lithography pattern. Therefore, the mounting method and stability of the objective lens are put forward with very high requirements.

[0032] In the prior art, the objective lens is usually fixed on the machine frame by screw assembly, and the position is ensured to be stable by rigid connection. However, this mounting method has the following technical problems: first, the objective lens as a high-precision optical element is extremely sensitive to external vibration. Due to the characteristics of rigid connection, the vibration on the frame will be directly transmitted to the objective lens, thereby affecting the lithography precision and even causing the imaging quality to decrease; second, the objective lens and the frame are usually made of different materials, and there is a large difference in their thermal expansion coefficients. In the case of environmental temperature change, the thermal expansion mismatch between them may cause a large internal stress, thereby affecting the optical performance and stability of the objective lens.

[0033] In view of the above problems, it is urgent to provide an improved objective lens damping device to effectively reduce the influence of vibration on the objective lens and reduce the internal stress caused by temperature change, so as to ensure the stability and lithography precision of the objective lens of the lithography machine.

[0034] Figure 1 The structure diagram of the objective lens damping device of the embodiment of the present application is shown in Figure 2 The cross-sectional structure diagram of the objective lens damping device of the embodiment of the present application is shown in Figure 1 And Figure 2 As shown in the present application, the objective lens damping device comprises: 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 the external vibration or temperature changes to buffer the vibration transmission and reduce the stress caused by thermal expansion effect.

[0035] The application discloses an objective lens damper with a flexible hinge structure, which can effectively reduce the influence of vibration and relieve thermal expansion stress while ensuring the stability of the objective lens installation, thereby improving the imaging precision and stability of the lithography machine.

[0036] Specifically, as shown in the drawings, Figure 1 The objective lens damper comprises an upper layer 1, a middle layer 2 and a lower layer 3. The upper layer 1 is an objective lens contact end and is provided with an interface for connecting with the objective lens. The lower layer 2 is a frame contact end and is provided with an interface for connecting with the frame. The middle layer 2 adopts a flexible hinge structure and provides necessary flexible support to realize vibration isolation and thermal stress buffering.

[0037] The objective lens damper adopts a flexible hinge structure, which can produce a slight elastic deformation when the external vibration or temperature changes, so as to reduce the stress influence on the objective lens. The objective lens damper adopts a multi-layer distributed structure, which comprises the upper layer 1, the middle layer 2 and the lower layer 3. 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 realize vibration isolation and thermal stress buffering. The lower layer 3 (frame contact end) is used for connecting with the frame of the lithography machine and providing overall structural support.

[0038] The middle layer 2 of the objective lens damper is connected with the upper layer 1 and the lower layer 3 through a flexible hinge to provide flexible support in the vertical, radial and tangential directions. The flexible hinge is adopted inside the objective lens damper, which can provide elastic force in each degree of freedom.

[0039] In the embodiment of the application, the flexible hinges in the objective lens damper are arranged in a central symmetry, so that the stress of the flexible hinges is uniformly distributed in each direction, and the deformation is prevented from being out of control due to excessive stress in a single direction. For example, Figure 2 A quarter structure of the objective lens damper is shown in the middle, and the flexible hinges can be uniformly arranged at four symmetric positions to ensure the stability of the entire objective lens damper.

[0040] Further, the objective lens is flexibly connected with the frame through the objective lens damper. The non-rigid connection mode is adopted, so that the objective lens is flexibly connected with the frame through the objective lens damper, and the direct transmission of vibration caused by rigid connection is avoided. The upper layer 1 and the lower layer 3 are respectively provided with a threaded or clamping groove structure, so as to facilitate installation and disassembly, and at the same time, ensure that no looseness or displacement occurs in the long-term use.

[0041] For example, Figure 2As 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 mounted between the objective lens and the frame, and the flexible connection is realized through the extensibility of the flexible hinge, and the objective lens is better protected, the designed objective lens damper belongs to passive damping, and only needs to be designed mechanically, is easy to realize, and better realizes vibration isolation and thermal decoupling.

[0042] Further, the middle layer 2 of the objective lens damper is a flexible hinge structure, and the vibration and thermal expansion are relieved through the flexibility of the flexible hinge, so as to ensure that the vertical stiffness is small.

[0043] Further, the thickness of the flexible hinge is determined according to simulation calculation. The thickness of the flexible hinge of the objective lens damper is determined by simulation calculation, different stiffnesses are calculated according to different thicknesses, the thickness of the flexible hinge is determined through the simulation method, and the rationality of the design and the damping effect are ensured.

[0044] In the embodiment of the application, the thickness of the flexible hinge is between 1-5mm. The thickness of the flexible hinge is determined by simulation calculation, and the stiffness is calculated through K=F / Δ, wherein F represents the applied load, and Δ represents the deformation amount, so as to ensure that the stiffness of the flexible block where the flexible hinge is located in the radial direction, the tangential direction and the vertical direction is less than 1*10 N / m.

[0045] In the application, the objective lens damper realizes passive damping through mechanical design, without the need of additional external energy input, so as to improve 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, so as to ensure that sufficient flexible buffering can be provided and the required stiffness can be maintained. In this way, the vibration transmission and the thermal stress influence are reduced without affecting the optical precision, so as to improve the stability and service life of the objective lens of the lithography machine.

[0046] The objective lens damping device of the utility model can realize the damping function through the following mode in use, specifically, including: designing objective lens damper, making it adopt flexible hinge structure;The thickness of the flexible hinge is determined by simulation calculation, and the stiffness of the damper is optimized;The objective lens interface is arranged on the upper layer of the objective lens damper, and the frame interface is arranged on the lower layer, and the mounting connection of the objective lens and the frame is realized;The flexible connection of the objective lens and the frame is realized through the elastic deformation of the flexible hinge.

[0047] The thickness of the flexible hinge is determined by simulation calculation, different thicknesses correspond to different stiffnesses, the thickness is optimized, the obtained stiffness meets the design requirement, and the thickness of the flexible hinge is determined.

[0048] Specifically, constraints are applied to 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 where the flexible hinge is located. According to the simulation results, the deformation amounts in the radial, tangential and vertical directions are measured, and the stiffness calculation formula (1) is used to calculate the stiffness of the flexible block in the radial, tangential and vertical directions, where K represents the stiffness, F represents the applied load, and Δ represents the deformation amount. The stiffness of the flexible block in the radial, tangential and vertical directions is calculated, where K represents the stiffness, F represents the applied load, and Δ represents the deformation amount.

[0049] The relationship between the flexible block, the bottom surface of the flexible block and the flexible hinge will be described below.

[0050] The flexible block is a part of the entire objective lens damper and usually includes a flexible hinge structure. The bottom surface (i.e., the bottom surface of the flexible block) is usually fixed or constrained to ensure that the entire flexible block is limited in certain directions in order to test or optimize the stiffness parameters.

[0051] 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 damping component of the flexible block. The bottom surface of the flexible block provides a fixed reference, and the flexible hinge determines the flexibility of the system. In stiffness calculation, the bottom surface of the flexible block is constrained, and the elastic deformation of the flexible hinge is measured to optimize the damping effect. Such design helps to improve the stability of the lithography machine objective lens while reducing the impact of vibration and thermal stress problems.

[0052] In the embodiments of the present application, the elastic deformation of the flexible hinge absorbs and attenuates vibration, preventing the vibration 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 between the objective lens and the frame due to the difference in thermal expansion coefficient. In the vertical (Z direction), radial (X / Y direction) and tangential (rotation direction), appropriate flexibility is provided to make the objective lens stable and not affected by rigid constraints.

[0053] Further, the thickness of the flexible hinge is optimized so that the stiffness is less than 1×10 N / m, ensuring that the vibration attenuation capability and thermal expansion compensation capability of the objective lens damper are optimal. By adjusting the thickness through simulation, the stiffness is moderate, which can effectively attenuate vibration and maintain the high precision stability of the optical system.

[0054] In the embodiments of the present application, the thickness of the flexible hinge is determined by simulation calculation method to ensure that the stiffness in different directions meets the design requirements.

[0055] In the embodiments of the present application, external vibration is absorbed and attenuated by the flexible hinge structure, effectively reducing the interference on the objective lens and improving the lithography precision; the flexible hinge can be elastically deformed with temperature change, reducing the internal stress caused by the difference in thermal expansion coefficient and improving the system stability; the thickness and stiffness of the flexible hinge are optimized by simulation calculation, so that the stiffness of the objective lens in different directions is controllable, meeting the requirements of high-precision lithography machines; passive vibration reduction is achieved by mechanical design, without additional energy input, and it is easy to be compatible with existing lithography machine systems.

[0056] In an optional actual mode, the optimal thickness and width of the flexible hinge are calculated by finite element analysis (FEA) to ensure that the vibration attenuation effect is optimal while maintaining the structural stability.

[0057] The present application provides an objective lens vibration reduction device, which provides an efficient objective lens vibration reduction scheme through a flexible hinge structure, can effectively reduce vibration transmission, relieve thermal expansion stress, and improve the optical stability of the lithography machine. Through precise simulation calculation and optimized structure design, the high performance and high reliability of the objective lens damper are ensured, and it has a wide application prospect in the field of semiconductor manufacturing.

[0058] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. An objective lens vibration damping device characterized by comprising: Comprising: An objective damper, the inner part of which adopts a flexible hinge structure, which provides elastic support when external vibration or temperature changes to buffer vibration transmission and reduce stress caused by thermal expansion effects; The objective damper comprises: an upper layer, a middle layer and a lower layer; The upper layer is the objective contact end, which is provided with an interface for connecting with the objective; 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 necessary flexible support to achieve vibration isolation and thermal stress buffering.

2. The objective lens vibration damping device according to claim 1, characterized by The objective is flexibly connected with the frame through the objective damper.

3. The objective damping device according to claim 1, wherein: The middle layer of the objective damper is connected with the upper layer and the lower layer through a flexible hinge to provide flexible support in the vertical, radial and tangential directions.

4. The objective damping device according to claim 1, wherein: The flexible hinge in the objective damper is arranged in a central symmetric manner to make the stress of the flexible hinge uniformly distributed in each direction.

5. The objective lens vibration damping device according to claim 4, characterized by The flexible hinge is uniformly arranged in four symmetric positions.

6. The objective damping device according to claim 1, wherein: The thickness of the flexible hinge is determined according to simulation calculation, and different thicknesses correspond to different stiffnesses.

7. The objective lens vibration damping device according to claim 6, characterized by The thickness of the flexible hinge is between 1-5mm.

8. The objective lens vibration damping device according to claim 7, characterized by The stiffness of the flexible hinge in each degree of freedom direction is less than 1×10 N / m.

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