Extreme ultraviolet light collection device and system

Abstract

The application provides an extreme ultraviolet light collecting device and system. The extreme ultraviolet light collecting device comprises: a spherical mirror group comprising a plurality of spherical mirrors, each spherical mirror in the spherical mirror group collects a part of extreme ultraviolet light rays emitted by an extreme ultraviolet light source; a plurality of mirror frames, the spherical mirrors are fixed on the mirror frames; and a driving mechanism, the driving mechanism drives the mirror frames to a specified position and angle, so that the extreme ultraviolet light rays collected by each spherical mirror converge at the same image point. The application can realize higher extreme ultraviolet light collecting efficiency while greatly reducing the cost of collecting optical elements.

Description

Technical Field

[0001] This invention relates to the field of extreme ultraviolet lithography technology, specifically to an extreme ultraviolet light collection device and system. Background Technology

[0002] Extreme ultraviolet (EUV) lithography has become one of the key technologies in next-generation photolithography. The EUV light collection system is a crucial component of EUV equipment. Common EUV generators include discharge plasma (DPP) and laser-induced plasma (LPP) types. Because materials typically exhibit strong absorption of EUV light, reflective optical elements are commonly used in EUV optical systems. However, due to limitations in fabrication technology, the cost of reflective optical elements is usually exponentially dependent on their size.

[0003] The goal of an extreme ultraviolet (EUV) light collection system is to collect and focus as much EUV light emitted from a plasma source as possible at the illumination point. While meeting cost and image space requirements, the spatial collection angle of the collection system relative to the plasma source should be maximized to achieve high EUV light collection efficiency. A common approach is to use large-sized optical elements to collect EUV light; the collection efficiency is linearly dependent on the size of the optical elements used for collection.

[0004] Commonly used reflective optical elements for collecting extreme ultraviolet light include ellipsoidal mirrors and Wolter-I type grazing incidence mirrors. However, large-sized mirrors of these two types are extremely difficult to manufacture, resulting in high costs for these two collection systems. This leads to a significant increase in the cost of extreme ultraviolet lithography machines, and they are not suitable for detection equipment that uses extreme ultraviolet light.

[0005] A search revealed Chinese invention patent application CN104345569A, which discloses an extreme ultraviolet (EUV) lithography light source system and an EUV exposure method. The system includes a collector for collecting EUV light; the collector comprises several mirrors configured in reflective and non-reflective states when collecting EUV light, and in a converging manner when the mirrors are in reflective state. This patent requires repeated movement of the mirrors, demanding high control precision and making it prone to errors. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an extreme ultraviolet light collection device and system that can achieve high extreme ultraviolet light collection efficiency while significantly reducing the cost of optical components used for collection.

[0007] According to one aspect of the present invention, an extreme ultraviolet light collecting device is provided, the device comprising:

[0008] A spherical mirror assembly includes multiple spherical mirrors, each of which collects a portion of the extreme ultraviolet light emitted from an extreme ultraviolet light source.

[0009] Multiple mirror mounts, with the spherical mirror fixed to the mirror mounts;

[0010] A driving mechanism drives the reflector frame to a specified position and angle, so that the extreme ultraviolet light collected by each of the spherical reflectors converges at the same image point.

[0011] Optionally, the light collection efficiency of the spherical mirror group is linearly related to the number of spherical mirrors.

[0012] Optionally, multiple spherical mirrors may use a uniform size and effective focal length.

[0013] Optionally, the drive mechanism is a stepper motor.

[0014] Optionally, each of the aforementioned mirror mounts has independent degrees of freedom for position and angle adjustment.

[0015] According to another aspect of the present invention, an extreme ultraviolet light collection system is provided, the system comprising:

[0016] The aforementioned extreme ultraviolet light collection device;

[0017] A controller is connected to the drive mechanism. The controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light emitted by the extreme ultraviolet light source is collected by the spherical reflector group and converges at the same image point.

[0018] Optionally, the system further includes a light intensity detector located at the image point position, which is used to acquire the extreme ultraviolet light intensity signal at the image point position; the controller is connected to the light intensity detector, and the controller controls the drive mechanism to move the reflector frame to a specified position and angle according to the extreme ultraviolet light intensity signal at the image point position.

[0019] Optionally, the controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light intensity signal measured by the light intensity detector is maximized.

[0020] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0021] 1. The extreme ultraviolet light collection device and system provided by the present invention collects a portion of the extreme ultraviolet light emitted by the extreme ultraviolet light source by each spherical mirror in the spherical mirror group. By adjusting the position and angle of each spherical mirror, the extreme ultraviolet light collected by different spherical mirrors is converged to the same image point, thereby achieving high-efficiency collection of extreme ultraviolet light.

[0022] 2. The extreme ultraviolet light collection device and system provided by the present invention use small-sized reflective optical elements to achieve high extreme ultraviolet light collection efficiency, which can reduce the requirements of the exposure system for light source power and high-cost large-sized reflective elements, thereby achieving high extreme ultraviolet light collection efficiency while significantly reducing the cost of optical elements for collection. Attached Figure Description

[0023] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0024] Figure 1 This is a schematic diagram of the structure of an extreme ultraviolet light collection device in one embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a light intensity detector placed at an image point to collect extreme ultraviolet light in one embodiment of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0027] The size of optical components is a key determinant of extreme ultraviolet (EUV) light collection efficiency, with a linear dependence between the two. Meanwhile, the manufacturing cost of optical components is exponentially dependent on size, resulting in persistently high costs for high-efficiency EUV light collection devices in current technologies.

[0028] To solve the above problems, refer to Figure 1This is a schematic diagram of an extreme ultraviolet (EUV) light collection device according to an embodiment of the present invention. The EUV light collection device includes a spherical mirror assembly, multiple mirror mounts, and a driving mechanism. The spherical mirror assembly includes multiple spherical mirrors, each of which collects a portion of the EUV light emitted from the EUV source. Multiple mirror mounts are used to fix the spherical mirrors, and the number of mirror mounts is the same as the number of spherical mirrors in the spherical mirror assembly. Each mirror mount is driven by a driving mechanism, which drives the mirror mount to a specified position and angle, thereby adjusting the position and angle of each spherical mirror. This ensures that the EUV light collected by each spherical mirror converges at the same image point, the position of which is determined by the positions of the multiple spherical mirrors in the spherical mirror assembly.

[0029] In this embodiment of the invention, each spherical mirror in the spherical mirror group collects a portion of the extreme ultraviolet (EUV) light emitted from the EUV source. Given the size of the spherical mirrors, multiple spherical mirrors are arranged on a specific curved surface to ensure that the light converges to the same image point. By adjusting the position and angle of each spherical mirror, the EUV light collected by different spherical mirrors is converged to the same image point, achieving high-efficiency collection of EUV light. The number of spherical mirrors is greater than or equal to two. The light collection efficiency of the spherical mirror group is linearly dependent on the number of spherical mirrors. Furthermore, the more spherical mirrors there are, the smaller the size and the lower the manufacturing cost; therefore, the collection efficiency is linearly dependent on the cost.

[0030] In some implementations, multiple spherical mirrors use a uniform size and effective focal length to facilitate the calculation of the position of each spherical mirror.

[0031] To facilitate adjustment of the position and angle of each spherical mirror, in some embodiments, a stepper motor is used as the drive mechanism. The stepper motor enables automated adjustment and control of the mirror mount's position and angle, allowing the mirror mount to translate and deflect in the vertical and horizontal directions. This, in turn, causes the spherical mirrors to shift and rotate in the corresponding positions, thus ensuring stable and accurate installation of the spherical mirrors at the designated locations. Each mirror mount has independent degrees of freedom for position and angle adjustment, facilitating the convergence of extreme ultraviolet light collected by each spherical mirror at the same image point.

[0032] Based on the same inventive concept, this invention provides an extreme ultraviolet light collection system, which includes a controller and the aforementioned extreme ultraviolet light collection device. The controller is connected to a drive mechanism, and the controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light emitted by the extreme ultraviolet light source is collected by the spherical reflector group and converges at the same image point.

[0033] In this embodiment of the invention, a spherical reflector is fixed with an adjustable spatial position and angle reflector frame. A drive mechanism such as a stepper motor is used to adjust the spatial position and angle of the reflector frame. The drive mechanism is controlled by a controller to achieve automated control of the reflector frame.

[0034] In some implementations, the system also includes a light intensity detector located at the image point location, which is used to acquire the extreme ultraviolet light intensity signal at the image point location; a controller is connected to the light intensity detector, and the controller controls the drive mechanism to move the reflector frame to a specified position and angle based on the extreme ultraviolet light intensity signal at the image point location.

[0035] In this embodiment of the invention, the controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light intensity signal measured by the light intensity detector is maximized. Specifically, the position of the maximum extreme ultraviolet light intensity (theoretical position) is first calculated, and the light intensity detector is used to measure at multiple positions near the theoretical position. The measurement results are then compared to obtain the final position of the maximum extreme ultraviolet light intensity.

[0036] like Figure 2 As shown, a light intensity detector is placed at the image point position, and the light intensity signal is provided to the controller as feedback. The controller then controls the stepper motor and other drive mechanisms to adjust the position and angle of the spherical mirror, so that the extreme ultraviolet light intensity signal measured by the light intensity detector is maximized. This ensures that the extreme ultraviolet light collected by the spherical mirrors in all the spherical mirror groups converges at the light intensity detector position, i.e., the image point.

[0037] In the above embodiments of the present invention, by adjusting the position and angle of multiple spherical mirrors, the collected extreme ultraviolet light is focused onto the same point. Compared with the large-size mirrors in the prior art, the multiple spherical mirrors in the spherical mirror group have the characteristic of small size. High extreme ultraviolet light collection efficiency is achieved by using small-size reflective optical elements. It is possible to complete the efficient collection of extreme ultraviolet light under low cost conditions, and reduce the requirements of the exposure system on light source power and high-cost large-size reflective elements.

[0038] In the above embodiments of the present invention, by adjusting the position and angle of multiple spherical reflectors, the position of the image point can be changed within a certain range. After the arrangement of multiple spherical reflectors is completed, it is not necessary to repeatedly move the spherical reflectors during the extreme ultraviolet light collection process. In addition, in the existing extreme ultraviolet light collection devices, harmful particles are easily attached to the surface of the collector, which affects the reflection efficiency and service life of the collection device. The collection device provided by the embodiments of the present invention has a large distance between the mirror surface and the image point, leaving sufficient space for the removal of harmful particles. A device for removing harmful particles can be installed between the image point and the mirror surface, thereby facilitating the implementation of work related to the removal of harmful particles.

[0039] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention. The preferred features described above can be used in any combination without conflict.

Claims

1. An extreme ultraviolet light collecting device, characterized in that, include: A spherical mirror assembly includes multiple spherical mirrors, each of which collects a portion of the extreme ultraviolet light emitted from an extreme ultraviolet light source. The number of spherical mirrors is greater than or equal to 2, and the light collection efficiency of the spherical mirror group is linearly related to the number of spherical mirrors. Multiple mirror mounts are provided, and the spherical mirrors are fixed on the mirror mounts; the number of mirror mounts is the same as the number of spherical mirrors in the spherical mirror group, and each mirror mount has independent position and angle adjustment freedom. A driving mechanism drives the reflector frame to a specified position and angle, so that the extreme ultraviolet light collected by each of the spherical reflectors converges at the same image point.

2. The extreme ultraviolet light collecting device according to claim 1, characterized in that, The multiple spherical mirrors use a uniform size and effective focal length.

3. The extreme ultraviolet light collecting device according to claim 1, characterized in that, The drive mechanism uses a stepper motor.

4. An extreme ultraviolet light collection system, characterized in that, include: The extreme ultraviolet light collecting device according to any one of claims 1-3; A controller is connected to the drive mechanism. The controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light emitted by the extreme ultraviolet light source is collected by the spherical reflector group and converges at the same image point.

5. The extreme ultraviolet light collection system according to claim 4, characterized in that, It also includes a light intensity detector located at the image point position, which is used to acquire the extreme ultraviolet light intensity signal at the image point position; the controller is connected to the light intensity detector, and the controller controls the drive mechanism to move the reflector frame to a specified position and angle according to the extreme ultraviolet light intensity signal at the image point position.

6. The extreme ultraviolet light collection system according to claim 5, characterized in that, The controller controls the drive mechanism to move the reflector frame to a specified position and angle, so that the extreme ultraviolet light intensity signal measured by the light intensity detector is maximized.

Images