Tin liquid drop target generation method and system

Abstract

The invention relates to the technical field of EUV light sources, and discloses a tin liquid drop target generation method and system. The tin liquid drop target generation system comprises two generation devices used for generating tin liquid drops and a signal generation device used for regulating and controlling splitting of the tin liquid drops, the two tin liquid drops collide with each other to generate tin liquid drop fog spots, and the diameter of the liquid drops in the fog spots is far smaller than that of the liquid drops used for colliding with each other. The tin liquid drop fog spots generated in the mode replace existing fog spots formed after pre-pulse bombardment, and the structure of the EUV light source is simplified. The shape and the size of the fogging spot can be adjusted through the collision angle, and strip-shaped liquid drop fogging spots can be conveniently produced and grown and are matched with the light spot of a lath laser. A strip laser with strip light spots can be adopted to bombard a strip-shaped low-density tin liquid drop fog spot target generated by liquid drop collision, and plasma containing EUV light can be generated. According to the technology, a new technical scheme is provided for the EUV light source, the droplet target is more conveniently and stably generated, and pre-pulse can be avoided during targeting.

Description

Technical Field

[0001] The invention relates to the technical field of EUV light sources, and in particular to a method and system for generating a tin droplet target. Background Art

[0002] The most advanced lithography machine is based on an EUV (extreme ultraviolet) light source with a wavelength of 13.5nm. The mainstream method of generating EUV light is laser-induced plasma (LPP) radiation, which focuses a high-peak power pulsed laser on the target tin droplet to ionize it into plasma, which then radiates EUV light with a wavelength of 13.5nm.

[0003] During the generation of droplet targets, the distance between two or more droplets is usually very small, close to the size of the droplets themselves. When the droplet spacing is too small, the plasma generated by laser target shooting will affect the nearby droplets, resulting in changes in the droplet shape and speed, and may also cause additional heat and energy release, thereby affecting the efficiency and stability of the EUV light source. It is very difficult to produce long-spacing, small-diameter droplet targets. The solution used by existing manufacturers is to first produce small-spacing droplets with a diameter of 6 microns, and then merge every 100 droplets into a droplet with a diameter of 30 microns, thereby increasing the droplet spacing. It is difficult to completely plasmatize a droplet with a diameter of 30 microns with a laser pulse. A pre-pulse is required to break it up into a disc-shaped fog spot composed of many tiny droplets, and then a main pulse is used to bombard the disc-shaped fog spot to fully plasmatize it. This solution has two major challenges, making the preparation of EUV light sources very difficult: one is to stably produce uniform tin droplets with a diameter of 6 microns; the other is the precise coordination of the pre-pulse and the main pulse with the droplets and the disc-shaped fog spots in time and space.

[0004] Therefore, the prior art needs to be further improved and enhanced. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method and system for generating a tin droplet target and an extreme ultraviolet light source system. The purpose is to generate a tin droplet fog spot by colliding two tin droplets, and the diameter of the droplets in the fog spot is much smaller than the droplets used for collision. The tin droplet fog spot generated in this way replaces the existing fog spot formed after pre-pulse bombardment, simplifying the structure of the EUV light source.

[0006] In the first aspect, the above-mentioned object of the present invention is achieved by the following technical solutions: a method and system for generating a tin droplet target, and an extreme ultraviolet light source system, wherein the system comprises:

[0007] Two tin droplet generating devices, the two tin droplet generating devices can be deflected relative to each other; the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°; the tin droplet generating device includes a pipeline, one end of the pipeline is connected to the liquid supply device, and the other end is connected to the nozzle bracket, and the nozzle bracket is provided with a crystal oscillator;

[0008] The signal generating device is connected to the crystal oscillator and is used to apply disturbance to the tin droplets to regulate the splitting of the tin droplets.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0010] As a preferred technical solution, in the tin droplet target generation system, the tin droplet generating device further comprises a piezoelectric ceramic component, and the piezoelectric ceramic component is controlled by a direct current sinusoidal signal.

[0011] As a preferred technical solution, the tin droplet target generation system further comprises a micro-motion platform, and the tin droplet generating device is connected to the micro-motion platform.

[0012] As a preferred technical solution, in the tin droplet target generation system, one of the two tin droplet generating devices is fixed on a cross-shaped component, and the cross-shaped component can move in the left and right directions; the two tin droplet generating devices are linked through the component.

[0013] As a preferred technical solution, in the tin droplet target generation system, the micro-motion platform includes: a micro-motion platform driven by piezoelectric ceramics and a micro-motion platform with a flexible hinge structure.

[0014] As a preferred technical solution, in the tin droplet target generation system, the liquid supply device is composed of a syringe and a mechanical pump, and the syringe is fixed above the mechanical pump.

[0015] In a second aspect, a method for generating a tin droplet target is provided. The method is based on the above-mentioned tin droplet target generating system, wherein the method for generating a tin droplet target comprises:

[0016] A direct current sinusoidal signal is used to control the vibration of the piezoelectric ceramics in the two tin droplet generating devices to generate monodisperse tin droplets, wherein a plurality of the monodisperse tin droplets form a droplet string;

[0017] The positional relationship between the two tin droplet generating devices is adjusted so that the tin droplets in the droplet strings generated by the two tin droplet generating devices collide to obtain the tin droplet target; the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°.

[0018] As a preferred technical solution, in the method for generating a tin droplet target, the tin droplet target is a long strip-shaped tin droplet target.

[0019] As a preferred technical solution, the tin droplet target generation method, the tin droplet target generation system also includes a micro-motion platform, the tin droplet generating device is connected to the micro-motion platform, wherein the micro-motion platform is controlled to adjust the horizontal eccentricity of two tin droplets that collide; the horizontal eccentricity is the ratio of the distance between the centers of the two tin droplets that collide to the particle size of the tin droplets; the particle sizes of the two tin droplets are the same.

[0020] In the third aspect, an extreme ultraviolet light source system is used for chip preparation and detection, wherein the extreme ultraviolet light source system includes the tin droplet target generation system and the laser as described above; the tin droplet target generation system generates long strip tin droplet targets, and the laser bombards the long strip tin droplet targets to generate EUV light.

[0021] Beneficial effects: Compared with the prior art, the tin droplet target generation system provided by the present invention generates a low-density tin droplet fog spot through the collision of tin droplets, and the diameter of the droplets in the fog spot is much smaller than the droplets used for collision. The shape and size of the fog spot can be adjusted by the collision angle, and a long strip of droplet fog spot can be easily generated to match the slab laser spot. A slab laser with a long light spot can be used to bombard the droplet collision to produce a long strip of low-density tin droplet fog spot target, which can generate plasma containing EUV light. This technology provides a new technical solution for EUV light sources, which is more convenient and stable to generate droplet targets, and pre-pulses can be eliminated when shooting. In addition, the generated long strip plasma is easily shaped into a long strip light spot by the subsequent optical system, which is more compatible with the shape of the slit in the scanning exposure system, thereby reducing aberrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the tin droplet target generation system provided by the present invention;

[0023] Figure 2 This is a schematic diagram of the long strip low-density tin droplet target provided by the present invention. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is

[0026] In fact, it is only illustrative and is not intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement of the components and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. For the techniques, methods known to ordinary technicians in the relevant fields,

[0029] The techniques, methods and devices may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0030] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0031] like Figure 1 As shown, a tin droplet target generation system provided by the present invention includes: a tin droplet generating device 10 for generating tin droplets and a signal generating device 20 for regulating the splitting of tin droplets. Among them, since a collision is required, two tin droplet generating devices need to be installed, and the two tin droplet generating devices can be deflected from each other, and the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°. The collision angle between the two droplets for collision can be adjusted by deflection. The tin droplet generating device includes a pipeline 100, which can be a polytetrafluoroethylene thin tube, one end of the pipeline is connected to the liquid supply device 30, and the other end is connected to the nozzle bracket 40, and the nozzle bracket 40 is provided with a crystal oscillator 400.

[0032] In the present invention, two tin droplet generating devices can be linked through components, the position of one tin droplet generating device remains fixed, and the other tin droplet generating device is connected to a cross-shaped component that can move left and right, such as allowing it to move in two dimensions within a range of 10cm*10cm.

[0033] In the present invention, by setting a crystal oscillator on the nozzle bracket, disturbance can be directly applied to the droplet string, thereby realizing the control of the splitting of the tin droplets. Specifically, the crystal oscillator can apply disturbance to the droplets by applying acoustic vibration, and this disturbance can change the shape and movement trajectory of the droplets, thereby affecting their splitting behavior. The split droplets collide again, which can better form fog spots.

[0034] In the present invention, the tin droplet generating device further includes a piezoelectric ceramic component (not shown), which is controlled by a DC sinusoidal signal, and the DC sinusoidal signal is used to vibrate the piezoelectric ceramic component of the droplet generator to achieve the generation of monodisperse droplets. In other words, the tin droplet target generation system provided by the present invention can generate a low-density tin droplet string, and then generate a low-density tin droplet target.

[0035] In the present invention, the tin droplet generating device is also connected to a micro-motion platform (not shown), by means of which the distance between the centers of the two droplets that collide can be adjusted, d is defined as the distance between the two droplets, D is the diameter of the droplet, and the horizontal eccentricity is d / D. The shape, size and size of the fog spot are adjusted by the collision angle and the eccentricity. More angles of adjustment are achieved to meet different application scenarios. It should be noted that the micro-motion platform can be set to one or two, which can be selected according to the needs of adjustment. The micro-motion platform includes but is not limited to a micro-motion platform based on piezoelectric ceramic drive and a micro-motion platform with a flexible hinge structure.

[0036] In the present invention, the liquid supply device 30 for supplying liquid to two tin droplet generating devices is composed of a syringe 300 and a mechanical pump 310 , and the syringe 300 is fixed above the mechanical pump 310 .

[0037] Based on the same inventive concept, the present invention also provides a method for generating a tin droplet target. The method is based on the above-mentioned tin droplet target generating system. The method comprises:

[0038] S10, using a DC sinusoidal signal to control the vibration of the piezoelectric ceramics in the two tin droplet generating devices to generate monodisperse tin droplets, and a plurality of the monodisperse tin droplets form a droplet string.

[0039] Specifically, the tin liquid is injected into a syringe through a mechanical pump, and then injected into a polytetrafluoroethylene tube by the syringe. The tin liquid flowing out of the polytetrafluoroethylene tube has a set speed. The speed setting is set according to the needs of the collision. It cannot be too small or too high. Because the speed is too small, the two tin droplets will not form a fog spot after the collision, but will aggregate. If the speed is too fast, the small-sized tin droplets formed after the collision of the two tin droplets will bounce and cannot form a relatively uniform fog spot. After the tin droplets are generated, in order to produce monodisperse tin droplets, it can be achieved by using a DC sinusoidal signal to control the vibration of the piezoelectric ceramics in the two tin droplet generating devices. It should be noted that the parameters of the DC sinusoidal signal can be set as needed and are not required here.

[0040] S20, adjusting the positional relationship between the two tin droplet generating devices so that the tin droplets in the droplet strings generated by the two tin droplet generating devices collide to obtain the tin droplet target; the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°.

[0041] Specifically, in order to change the intersection angle of the tin droplets used for collision, the two tin droplet generating devices can be rotated at an angle of 2θ, such as 60°. That is to say, the angle formed by the intersection of the droplet strings formed by the two tin droplet generating devices is 60°. At this time, the collision of the two droplets is a head-on collision (the collision contact area is the largest). In order to form the required fog spot shape and obtain a tin droplet target of a fixed shape, the eccentricity of one and / or two colliding tin droplets can be adjusted through a micro-motion platform. Compared with the existing collision that is only a head-on collision or an up and down eccentric collision, it has better flexibility and stronger adaptability.

[0042] In the present invention, the formed tin droplet target is a long strip tin droplet target (combined with Figure 2 ), which can generate long strips of low-density tin droplets, making it easier to stably generate droplet targets, and eliminating the need for pre-pulses when shooting. In addition, the generated long strips of plasma can be easily shaped into long strips of light spots by the subsequent optical system, which better matches the shape of the slit in the scanning exposure system, thereby reducing aberrations.

[0043] In summary, the tin droplet target generation system provided by the present invention includes two generating devices for generating tin droplets and a signal generating device for regulating the splitting of tin droplets. By colliding two tin droplets, a tin droplet fog spot is generated, and the droplet diameter in the fog spot is much smaller than the droplet used for collision. The tin droplet fog spot generated in this way replaces the existing fog spot formed after the pre-pulse bombardment, simplifying the structure of the EUV light source. The shape and size of the fog spot can be adjusted by the collision angle, and the long strip droplet fog spot can be easily generated to match the slab laser spot. The long strip low-density tin droplet fog spot target generated by the droplet collision can be bombarded by a slab laser with a long strip spot, and a plasma containing EUV light can be generated. This technology provides a new technical solution for the EUV light source, which is more convenient and stable to generate droplet targets, and pre-pulses can be exempted when shooting. And the long strip plasma generated is easily shaped into a long strip spot by the subsequent optical system, which is more matched with the shape of the slit in the scanning exposure system, thereby reducing aberrations.

[0044] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A tin droplet target generation system, characterized in that: include: Two tin droplet generating devices, the two tin droplet generating devices can be deflected relative to each other; the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°; the tin droplet generating device includes a pipeline, one end of the pipeline is connected to the liquid supply device, and the other end is connected to the nozzle bracket, and the nozzle bracket is provided with a crystal oscillator; The signal generating device is connected to the crystal oscillator and is used to apply disturbance to the tin droplets to regulate the splitting of the tin droplets.

2. The tin droplet target generation system according to claim 1, characterized in that: The tin droplet generating device further comprises a piezoelectric ceramic component, and the piezoelectric ceramic component is controlled by a direct current sinusoidal signal.

3. The tin droplet target generation system according to claim 1, characterized in that: The tin droplet target generation system also includes a micro-motion platform, and the tin droplet generating device is connected to the micro-motion platform.

4. The tin droplet target generation system according to claim 1, characterized in that: One of the two tin droplet generating devices is fixed on a cross-shaped component, and the cross-shaped component can move in the left and right directions; the two tin droplet generating devices are linked through the component.

5. The tin droplet target generation system according to claim 3, characterized in that: The micro-motion platform includes: a micro-motion platform driven by piezoelectric ceramics and a micro-motion platform with a flexible hinge structure.

6. The tin droplet target generation system according to claim 1, characterized in that: The liquid supply device consists of a syringe and a mechanical pump, and the syringe is fixed above the mechanical pump.

7. A method for generating a tin droplet target, the method being based on the tin droplet target generating system according to claim 1, characterized in that: The tin droplet target generation method comprises: A direct current sinusoidal signal is used to control the vibration of the piezoelectric ceramics in the two tin droplet generating devices to generate monodisperse tin droplets, wherein a plurality of the monodisperse tin droplets form a droplet string; The positional relationship between the two tin droplet generating devices is adjusted so that the tin droplets in the droplet strings generated by the two tin droplet generating devices collide to obtain the tin droplet target; the angle formed by the intersection of the droplet strings generated by the two tin droplet generating devices is 2θ, 0<2θ<180°.

8. The method for generating a tin droplet target according to claim 7, characterized in that: The tin liquid drop target is a long strip tin liquid drop target.

9. The method for generating a tin droplet target according to claim 7, wherein the tin droplet target generating system further comprises a micro-motion platform, and the tin droplet generating device is connected to the micro-motion platform, characterized in that: The micro-motion platform is controlled to adjust the horizontal eccentricity of the two tin droplets that collide; the horizontal eccentricity is the ratio of the distance between the centers of the two tin droplets that collide to the particle size of the tin droplets; the particle sizes of the two tin droplets are the same.

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