Metal droplet control device and method, extreme ultraviolet light source equipment and exposure system

Abstract

The invention belongs to the technical field of semiconductor manufacturing, and discloses a metal liquid drop control device and method, extreme ultraviolet light source equipment and an exposure system.The metal liquid drop control device comprises a liquid drop generator, at least two first lasers, a correlation sensor and a controller, a spray head is arranged on the liquid drop generator, and the spray head can spray out first liquid drops; emitting heads of all the first lasers are uniformly distributed around the dripping track of the first liquid drop, first light beams emitted by all the first lasers intersect to form a potential well point, and the potential well point is located on the dripping track of the first liquid drop; the correlation sensor comprises a transmitter and a receiver, a transmitting head of the transmitter directly faces the potential well point, the transmitter and the receiver are located on the two opposite sides of the potential well point respectively, so that a second light beam emitted by the transmitter can pass through the potential well point and reach the receiver, and the receiver is in signal connection with the controller; and the controller can control the first laser to be turned on when the receiver receives the second light beam, so that the first liquid drops are controlled to be homogenized after being coagulated.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a metal droplet control device and method, extreme ultraviolet light source equipment and an exposure system. Background Art

[0002] Photolithography refers to the technology of transferring the pattern on the mask to the substrate with the help of photoresist (also known as photoresist) under the action of light. As photolithography rapidly develops towards more sophisticated manufacturing, semiconductor production processes have been able to produce semiconductor devices with increasingly fine feature sizes. These include exposure systems for extreme ultraviolet light source equipment and projection reflective optical equipment. Methods for generating extreme ultraviolet light include, but are not limited to, converting materials with elements (such as xenon, lithium or tin) into a plasma state and emitting spectral lines within the extreme ultraviolet range.

[0003] Laser-generated plasma is usually used to bombard tin metal (in the form of droplets, plates, strips, streams or material clusters) with a size of tens of microns with high-energy pulsed lasers to form the required plasma that can radiate extreme ultraviolet light. Usually, tin droplets pass through a cylindrical pipe, and Plateau-Rayleigh instability will occur under the action of surface tension, and the cylindrical droplets will spontaneously turn into circular monodisperse droplets. Ultrasonic waves are used to generate micro-perturbations and different air pressures to control the emission frequency, size, spacing and other parameters of the tin droplets. In the prior art, an annular piezoelectric ceramic sleeve is used on the outlet pipe of the droplet generator to directly apply ultrasonic waves to the tin droplets. However, due to various interference factors, the tin droplets usually still have tin droplets of uneven size such as satellite droplets, which affect the generation of extreme ultraviolet light.

[0004] Therefore, there is an urgent need to propose a metal droplet control device and method, an extreme ultraviolet light source device and an exposure system to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a metal droplet control device to achieve uniform control of the size of the metal droplets and reduce the spatial jitter of the metal droplets.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A metal droplet control device, comprising:

[0008] A droplet generator, wherein a nozzle is disposed on the droplet generator and the nozzle can spray a first droplet;

[0009] At least two first lasers, the emission heads of all the first lasers are evenly distributed around the dripping track of the first liquid drop, and the first light beams emitted by all the first lasers intersect to form a potential well point, and the potential well point is located on the dripping track of the first liquid drop;

[0010] A through-beam sensor, the through-beam sensor comprises a transmitter and a receiver, the transmitter head of the transmitter is directly facing the potential well point, and the transmitter and the receiver are respectively located on two opposite sides of the potential well point, so that the second light beam emitted by the transmitter can pass through the potential well point and reach the receiver;

[0011] The receiver is connected to the controller by signal, and the controller can control the first laser to turn on when the receiver receives the second light beam.

[0012] Preferably, the potential well point is spaced apart from the nozzle.

[0013] Preferably, the emitter is capable of adjusting the diameter of the second light beam.

[0014] Preferably, the metal droplet control device further comprises a box body, the box body is provided with a cavity, and the emission head of the first laser and the nozzle of the droplet generator are located in the cavity.

[0015] Preferably, the cavity is a vacuum cavity.

[0016] Another object of the present invention is to provide an extreme ultraviolet light source device to achieve uniform control of the size of metal droplets in the extreme ultraviolet light source device and improve the stability of the extreme ultraviolet light generated by the extreme ultraviolet light source device.

[0017] To achieve this object, the present invention adopts the following technical solutions:

[0018] An extreme ultraviolet light source device includes a second laser and the above-mentioned metal droplet control device. The light beam emitted by the second laser intersects the dripping trajectory of the first droplet at a bombardment point. Along the dripping direction of the first droplet, the bombardment point is located downstream of the potential well point.

[0019] Another object of the present invention is to provide an exposure system to achieve uniform control of the size of metal droplets of an extreme ultraviolet light source device in the exposure system, improve the stability of the extreme ultraviolet light generated by the extreme ultraviolet light source device, and improve exposure accuracy.

[0020] To achieve this object, the present invention adopts the following technical solutions:

[0021] An exposure system comprises a projection reflection optical device, an optical path pipeline and the above-mentioned extreme ultraviolet light source device, wherein the extreme ultraviolet light source device is connected to the projection reflection optical device through the optical path pipeline.

[0022] Another object of the present invention is to provide a method for controlling metal droplets to achieve uniform control of the size of metal droplets.

[0023] To achieve this object, the present invention adopts the following technical solutions:

[0024] A method for controlling metal droplets, using the metal droplet control device as described above, comprises the following steps:

[0025] S1, turning on the first laser, so that the first light beams emitted by the first laser intersect and form a potential well point;

[0026] Turning on the droplet generator so that the first droplet ejected by the droplet generator reaches the potential well point;

[0027] S2. Turn off the first laser.

[0028] Preferably, step S1 further comprises:

[0029] Turn on the through-beam sensor so that the second light beam emitted by the transmitter passes through the potential well point and reaches the receiver;

[0030] The nozzle sprays a plurality of first liquid droplets, which condense at the potential well point and form second liquid droplets. When the second light beam emitted by the transmitter is completely blocked by the second liquid droplets and cannot reach the receiver, the control executes step S2.

[0031] Preferably, the metal droplet control method further comprises:

[0032] S3, the second droplet continues to drip away from the potential well point, and the second light beam emitted by the transmitter reaches the receiver again, controlling the first laser to turn on.

[0033] Beneficial effects of the present invention:

[0034] The present invention provides a metal droplet control device and method, extreme ultraviolet light source equipment and exposure system. The metal droplet control device includes a droplet generator, at least two first lasers, a beam sensor and a controller. The droplet generator is provided with a nozzle, which can spray out a first droplet; the emission heads of all first lasers are evenly distributed around the droplet trajectory of the first droplet, and the first light beams emitted by all first lasers intersect to form a potential well point, which is located on the droplet trajectory of the first droplet; the beam sensor includes a transmitter and a receiver, the emission head of the transmitter is directly opposite to the potential well point, the transmitter and the receiver are respectively located on opposite sides of the potential well point, so that the second light beam emitted by the transmitter can pass through the potential well point and reach the receiver, the receiver is connected to the controller signal, and the controller can control the opening of the first laser when the receiver receives the second light beam. The first light beam emitted by the first laser converges at a certain point in the spraying direction of the nozzle of the droplet generator to form a potential well point. Since the potential well point has a binding effect on the first droplet, the jitter of the first droplet in space, such as left-right deviation or up-and-down jumping, is effectively reduced. When the first droplet enters the potential well point, its speed is weakened and its temperature is increased. The following multiple first droplets will collide and condense at the potential well point to form condensed droplets. As the multiple first droplets continue to condense, the condensed droplets gradually increase in size. Aim the transmitter at the center of the potential well point so that the second light beam emitted by the transmitter passes through the potential well point and illuminates the receiver. When the diameter of the condensed droplet at the potential well point is equal to the diameter of the second light beam (for ease of understanding, the condensed droplet at this time will be referred to as the second droplet below), the second droplet will block the second light beam at the potential well point. At this time, the second light beam cannot illuminate the receiver, and the receiver outputs a feedback signal to the controller to turn off the first laser. The second droplet continues to drip after losing its restraint. After the second droplet leaves the potential well point, the second light beam passes through the potential well point again to illuminate the receiver. The receiver outputs a feedback signal to the controller to turn on the first laser to form the next second droplet at the potential well point, thereby achieving control over the uniformity of the size of the second droplet. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of the metal droplet control device provided by the present invention;

[0036] Figure 2 is a schematic diagram of the dripping of a plurality of first liquid droplets when the first liquid droplets are offset to the left and right relative to the potential well point in the present invention;

[0037] Figure 3 is a schematic diagram of the dripping of a plurality of first liquid droplets when the size of the first liquid droplets changes periodically in the present invention;

[0038] Figure 4 It is a schematic diagram of the dripping situation when the sizes of multiple first liquid droplets randomly change in the present invention.

[0039] In the figure:

[0040] 1. Droplet generator; 11. Nozzle; 2. First laser; 21. First light beam; 3. Potential well point; 31. First droplet; 32. Second droplet; 4. Target sensor; 41. Transmitter; 411. Second light beam; 42. Receiver; 5. Controller; 6. Box; 61. Cavity; 7. Signal collector; 8. Power supply. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0042] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0045] This embodiment provides a metal droplet control device to achieve uniform control of the size of the metal droplets and reduce the spatial jitter of the metal droplets.

[0046] Specifically, Figure 1As shown, the metal droplet control device includes a droplet generator 1, at least two first lasers 2, a beam sensor 4 and a controller 5. The droplet generator 1 is provided with a nozzle 11, which can spray out a first droplet 31; the emission heads of all the first lasers 2 are evenly distributed around the dripping trajectory of the first droplet 31, and at least the first light beams 21 emitted by all the first lasers 2 intersect to form a potential well point 3, and the potential well point 3 is located on the dripping trajectory of the first droplet 31; the beam sensor 4 includes a transmitter 41 and a receiver 42, the emission head of the transmitter 41 is directly opposite to the potential well point 3, the transmitter 41 and the receiver 42 are respectively located on opposite sides of the potential well point 3, so that the second light beam 411 emitted by the transmitter 41 can pass through the potential well point 3 and reach the receiver 42, the receiver 42 is connected to the controller 5 signal, and the controller 5 can control the opening of the first laser 2 when the receiver 42 receives the second light beam 411. When the first light beam 21 emitted by the first laser 2 irradiates the first droplet 31, the momentum of the photon changes. According to the law of conservation of momentum, the first light beam 21 generates a force on the first droplet 31. The force can balance the gravity and other external forces of the first droplet 31, thereby greatly reducing the potential energy of the first droplet 31, and restraining the first droplet 31 in space, thereby effectively reducing the jitter of the first droplet 31 in space, such as left-right deviation or up-and-down jumping. By evenly distributing the emission heads of all first lasers 2 around the dripping trajectory of the first droplet 31, the first light beams 21 emitted by all first lasers 2 are evenly distributed around the dripping trajectory of the first droplet 31 and intersect to form a potential well point 3. Therefore, the first light beams 21 emitted by all first lasers 2 are evenly distributed around the potential well point 3, which reduces the probability of the first droplet 31 at the potential well point 3 being deflected due to the biased light pressure, thereby increasing the probability of the first droplet 31 continuing to drip along the original dripping direction after passing through the potential well point 3, thereby further reducing the left and right deviation of the first droplet 31. The first light beams 21 emitted by the first laser 2 converge at a certain point in the spraying direction of the nozzle 11 of the droplet generator 1 to form a potential well point 3. Since the potential well point 3 has a binding effect on the first droplet 31, when the first droplet 31 enters the potential well point 3, its speed is reduced and its temperature is increased. The following multiple first droplets 31 will collide and condense at the potential well point 3 to form condensed droplets. As the multiple first droplets 31 continue to condense, the condensed droplets gradually increase in size.Aim the transmitter 41 at the center of the potential well point 3 so that the second light beam 411 emitted by the transmitter 41 passes through the potential well point 3 and illuminates the receiver 42. When the diameter of the condensed droplet at the potential well point 3 is equal to the diameter of the second light beam 411 (for ease of understanding, the condensed droplet at this time will be referred to as the second droplet 32 ​​below), the second droplet 32 ​​will block the second light beam 411 at the potential well point 3. At this time, the second light beam 411 cannot illuminate the receiver 42, and then the receiver 42 outputs a feedback signal to the controller 5 to turn off the first laser 2. The second droplet 32 ​​continues to drip after losing its restraint. After the second droplet 32 ​​leaves the potential well point 3, the second light beam 411 passes through the potential well point 3 again to illuminate the receiver 42. The receiver 42 outputs a feedback signal to the controller 5 to turn on the first laser 2 to form the next second droplet 32 ​​at the potential well point 3, thereby achieving control over the uniform size of the second droplet 32.

[0047] In this embodiment, the first laser 2 is a carbon dioxide pulse laser. In other embodiments, the first laser 2 may be a semiconductor pulse laser or a solid pulse laser. In this embodiment, the number of the first lasers 2 is 2. In other embodiments, the number of the first lasers 2 may be 4, 5 or 6. In this embodiment, the metal droplets are tin droplets. In other embodiments, the metal droplets may also be lithium droplets.

[0048] Furthermore, the metal droplet control device also includes a signal collector 7 and a power supply 8, the input end of the signal collector 7 is connected to the receiver 42 by signal, the output end of the signal collector 7 is connected to the controller 5 by signal, the power supply 8 is connected to the controller 5 by signal, the power supply 8 is electrically connected to the first laser 2, and the feedback signal output by the receiver 42 is transmitted to the controller 5 through the signal collector 7, and the controller 5 controls the on and off of the current between the power supply 8 and the first laser 2. In other embodiments, the feedback signal output by the receiver 42 can be directly fed back to the controller 5. In other embodiments, the controller 5 can control the on and off of the first laser 2 by controlling the button of the first laser 2 switch.

[0049] Furthermore, the potential well point 3 is spaced apart from the nozzle 11. When the first droplet 31 condenses into the second droplet 32 ​​at the potential well point 3 and is about to continue dripping, if the potential well point 3 is contacted with the nozzle 11, the new first droplet 31 sprayed from the nozzle 11 will condense with the second droplet 32, thereby making it impossible to form second droplets 32 of uniform size.

[0050] Optionally, the emitter 41 can adjust the diameter of the second light beam 411. When the size of the condensed droplet reaches the diameter of the second light beam 411, the second light beam 411 emitted by the emitter 41 is blocked. At this time, the receiver 42 outputs a feedback signal to the controller 5 to turn off the first laser 2, allowing the condensed second droplet 32 ​​to leave the potential well point 3 and continue to drip. Therefore, by adjusting the diameter of the second light beam 411, the size of the condensed second droplet 32 ​​can be adjusted. It should be noted that in the prior art, the diameter of the second light beam 411 emitted by the emitter 41 in the beam sensor 4 can be adjusted, which will not be repeated here.

[0051] Optionally, the diameter of the second light beam 411 ranges from 9 μm to 110 μm. Since the diameter of the second droplet 32 ​​is determined by the diameter of the second light beam 411, the diameter of the coagulated second droplet 32 ​​is maintained at 9 μm to 110 μm. In this embodiment, the diameter of the second light beam 411 is 50 μm. In other embodiments, the diameter of the second light beam 411 is 9 μm, 60 μm or 110 μm.

[0052] Optionally, the metal droplet control device further includes a box 6, which is provided with a cavity 61, and the emission head of the first laser 2 and the nozzle 11 of the droplet generator 1 are located in the cavity 61 to prevent impurities from mixing into the first droplet 31 and the second droplet 32 ​​and affecting the generation of extreme ultraviolet light. In other embodiments, the entire first laser 2 is placed in the cavity 61 and / or the entire droplet generator 1 is placed in the cavity 61.

[0053] Furthermore, the cavity 61 is a vacuum cavity, which prevents the first droplet 31 and the second droplet 32 ​​from being oxidized prematurely, thereby ensuring the stability of the generation of extreme ultraviolet light.

[0054] Optionally, the frequency of the first droplet 31 ejected by the nozzle 11 is 990Hz-11MHz, and the first droplet 31 with a size of 0.09μm-11μm is obtained by controlling the emission frequency of the droplet generator 1, so that the distance between two adjacent first droplets 31 ejected by the nozzle 11 is greater than 90μm, so as to avoid the two adjacent first droplets 31 being too close. When the first droplet 31 condenses into the second droplet 32 ​​at the potential well point 3 and is about to continue to drip, the new first droplet 31 behind condenses with the second droplet 32, resulting in the inability to form a second droplet 32 ​​with controllable and uniform size. In this embodiment, the frequency of the first droplet 31 ejected by the nozzle 11 is 50kHz. In other embodiments, the frequency of the first droplet 31 ejected by the nozzle 11 can be 990Hz, 1MHz or 11MHz, etc. In this embodiment, the size of the first droplet 31 is 5μm. In other embodiments, the size of the first droplet 31 is 0.09μm, 6μm or 11μm, etc. In this embodiment, the distance between two adjacent first liquid droplets 31 sprayed by the nozzle 11 is 100 μm. In other embodiments, the distance between two adjacent first liquid droplets 31 sprayed by the nozzle 11 may be 90 μm, 200 μm, or 300 μm.

[0055] like Figures 2 to 4 As shown, in the metal droplet control device, due to the existence of the potential well point 3, the multiple first droplets 31 ejected by the droplet generator 1 will automatically focus toward the center. Figure 2 The first droplet 31 shown is offset left and right relative to the potential well point 3, or Figure 3 The first droplet 31 with periodic size variation shown, or Figure 4 The first liquid droplets 31 with randomly varying sizes shown in the figure will all be focused on the potential well point 3 , and the potential well point 3 will exert a binding effect on the first liquid droplets 31 , thereby effectively reducing the jitter of the first liquid droplets 31 .

[0056] This embodiment also provides an extreme ultraviolet light source device to achieve control over the uniformity of the size of metal droplets in the extreme ultraviolet light source device and improve the stability of the extreme ultraviolet light generated by the extreme ultraviolet light source device.

[0057] Specifically, an extreme ultraviolet light source device includes a second laser and the above-mentioned metal droplet control device, the light beam emitted by the second laser intersects with the dripping trajectory of the first droplet 31 at the impact point, and along the dripping direction of the first droplet 31, the impact point is located downstream of the potential well point 3. The droplet generator in the metal droplet control device generates a first droplet 31 with less jitter, the first droplet 31 passes through the potential well point 3 and continues to drip in the original direction, the light beam emitted by the second laser accurately bombards the first droplet 31 to diffuse it into a suitable shape distribution, and generates extreme ultraviolet light through the laser excitation plasma physical mechanism. The first light beams 21 emitted by all the first lasers 2 are evenly distributed around the potential well point 3, reducing the probability of the first droplet 31 located at the potential well point 3 being offset due to the deflected light pressure, thereby increasing the probability of the first droplet 31 continuing to drip along the original dripping direction after passing through the potential well point 3, thereby achieving the effect of reducing the jitter of the first droplet 31. The droplet generator 1 produces a first droplet 31 with less jitter and a constant drop direction, so that the second laser can accurately bombard the first droplet 31, thereby improving the stability of the extreme ultraviolet light generation. In this embodiment, the second laser is a carbon dioxide pulse laser. In other embodiments, the second laser can be a semiconductor pulse laser or a solid pulse laser.

[0058] This embodiment further provides an exposure system to achieve uniform control of the size of metal droplets of an extreme ultraviolet light source device in the exposure system, improve the stability of the extreme ultraviolet light generated by the extreme ultraviolet light source device, and improve exposure accuracy.

[0059] Specifically, an exposure system includes a projection reflection optical device, an optical path pipeline and the above-mentioned extreme ultraviolet light source device, and the extreme ultraviolet light source device is connected to the projection reflection optical device through the optical path pipeline. The droplet generator 1 gives a first droplet 31 with less jitter and constant dripping direction, so that the second laser can accurately bombard the first droplet 31, thereby improving the stability of the extreme ultraviolet light generated in the extreme ultraviolet light source device, so that the projection reflection optical device receives light with stable intensity and angle, and can accurately project the pattern onto the exposed object such as the chip during exposure, thereby improving the resolution and accuracy of the exposure pattern, and further improving the process accuracy of products such as chips.

[0060] This embodiment further provides a metal droplet control method to achieve uniform control of the size of the metal droplets.

[0061] Specifically, a metal droplet control method as described above includes: S1, turning on the first laser 2, so that the first light beams 21 emitted by the first laser 2 intersect and form a potential well point 3; turning on the droplet generator 1, so that the first droplet 31 ejected by the droplet generator 1 reaches the potential well point 3. S2, turning off the first laser 2. The first light beam 21 emitted by the first laser 2 has a binding effect on the first droplet 31, which can effectively reduce the jitter of the first droplet 31. By evenly distributing the emission heads of all the first lasers 2 around the dripping trajectory of the first droplet 31, the first light beams 21 emitted by all the first lasers 2 are evenly distributed around the dripping trajectory of the first droplet 31 and intersect to form a potential well point 3. Therefore, the first light beams 21 emitted by all the first lasers 2 are evenly distributed around the potential well point 3, which reduces the probability of the first droplet 31 at the potential well point 3 being offset due to the deflected light pressure, thereby increasing the probability of the first droplet 31 continuing to drip along the original dripping direction after passing through the potential well point 3, thereby further reducing the jitter of the first droplet 31. In this embodiment, the first laser 2 and the droplet generator 1 are turned on at the same time. In other embodiments, the first laser 2 may be turned on first and then the droplet generator 1, or the droplet generator 1 may be turned on first and then the first laser 2.

[0062] Furthermore, step S1 also includes turning on the beam sensor 4, so that the second light beam 411 emitted by the emitter 41 passes through the potential well point 3 and reaches the receiver 42; the nozzle 11 sprays multiple first droplets 31, and the multiple first droplets 31 condense and form second droplets 32 at the potential well point 3. When the second light beam 411 emitted by the emitter 41 is completely blocked by the second droplet 32 ​​and cannot reach the receiver 42, the control executes step S2. Since the potential well point 3 has a binding effect on the first droplet 31, when the first micro droplet enters the potential well point 3, the speed is reduced and the temperature is increased. The following multiple first droplets 31 will collide and condense at the potential well point 3 until the second droplet 32 ​​is formed. Aim the transmitter 41 at the center of the potential well point 3. When the second droplet 32 ​​is formed at the potential well point 3, the second droplet 32 ​​will block the second light beam 411 emitted by the transmitter 41 at the potential well point 3. At this time, the second light beam 411 cannot irradiate the receiver 42. The receiver 42 outputs a feedback signal to the controller 5 to turn off the first laser 2, allowing the second droplet 32 ​​to leave the potential well point 3 and continue to move forward.

[0063] Furthermore, the metal droplet control method also includes, S3, the second droplet 32 ​​continues to drip away from the potential well point 3, the second light beam 411 emitted by the emitter 41 reaches the receiver 42 again, and the first laser 2 is controlled to turn on. The potential well point 3 formed by the first light beam 21 emitted by all the first lasers 2 has a binding effect on the first droplet 31 ejected by the droplet generator 1, reduces the speed of the first droplet 31, causes it to collide with the subsequent first droplet 31 and condense to form a second droplet 32, thus forming a cycle, obtaining second droplets 32 of uniform size, and improving the uniformity of the size of the second droplets 32.

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A metal droplet control device, characterized in that: include: A droplet generator (1), wherein the droplet generator (1) is provided with a nozzle (11), and the nozzle (11) is capable of spraying a first droplet (31); at least two first lasers (2), the emission heads of all the first lasers (2) being evenly distributed around the dripping trajectory of the first liquid drop (31), and the first light beams (21) emitted by all the first lasers (2) intersecting to form a potential well point (3), and the potential well point (3) being located on the dripping trajectory of the first liquid drop (31); A beam sensor (4), the beam sensor (4) comprising a transmitter (41) and a receiver (42), the transmitter head of the transmitter (41) facing the potential well point (3), the transmitter (41) and the receiver (42) being located on opposite sides of the potential well point (3), so that a second light beam (411) emitted by the transmitter (41) can pass through the potential well point (3) and reach the receiver (42); A controller (5), the receiver (42) is connected to the controller (5) by signal, and the controller (5) can control the first laser (2) to turn on when the receiver (42) receives the second light beam (411).

2. The metal droplet control device according to claim 1, characterized in that: The potential well point (3) and the nozzle (11) are arranged at a distance.

3. The metal droplet control device according to claim 1, characterized in that: The emitter (41) is capable of adjusting the diameter of the second light beam (411).

4. The metal droplet control device according to claim 1, characterized in that: The metal droplet control device further comprises a box (6), wherein the box (6) is provided with a cavity (61), wherein the emission head of the first laser (2) and the nozzle (11) of the droplet generator (1) are located in the cavity (61).

5. The metal droplet control device according to claim 4, characterized in that: The cavity (61) is a vacuum cavity.

6. An extreme ultraviolet light source device, characterized in that: It comprises a second laser and the metal droplet control device according to any one of claims 1 to 5, wherein the light beam emitted by the second laser intersects with the dripping trajectory of the first droplet (31) at a bombardment point, and along the dripping direction of the first droplet (31), the bombardment point is located downstream of the potential well point (3).

7. An exposure system, characterized in that: It comprises a projection and reflection optical device, an optical path pipeline and the extreme ultraviolet light source device according to claim 6, wherein the extreme ultraviolet light source device is connected to the projection and reflection optical device through the optical path pipeline.

8. A method for controlling metal droplets, using the metal droplet control device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, turning on the first laser (2), so that the first light beams (21) emitted by the first laser (2) intersect and form the potential well point (3); Opening the droplet generator (1) so that the first droplet (31) ejected from the droplet generator (1) reaches the potential well point (3); S2. Turn off the first laser (2).

9. The metal droplet control method according to claim 8, characterized in that: The step S1 further comprises: Turning on the corresponding sensor (4) so ​​that the second light beam (411) emitted by the transmitter (41) passes through the potential well point (3) and reaches the receiver (42); The nozzle (11) is caused to spray out a plurality of the first liquid droplets (31), and the plurality of the first liquid droplets (31) condense at the potential well point (3) to form second liquid droplets (32). When the second light beam (411) emitted by the transmitter (41) is completely blocked by the second liquid droplets (32) and cannot reach the receiver (42), the step S2 is controlled to be executed.

10. The metal droplet control method according to claim 9, characterized in that: The metal droplet control method further comprises: S3, the second liquid drop (32) continues to drip away from the potential well point (3), and the second light beam (411) emitted by the transmitter (41) reaches the receiver (42) again, controlling the first laser (2) to turn on.

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