CN113009787B - Extreme ultraviolet light generating method and device - Google Patents

Abstract

The application relates to an extreme ultraviolet light generating method and device, wherein the method comprises the following steps: the method comprises the following steps: controlling a target droplet generator to generate target droplets; determining preset trigger time according to the starting time of the target liquid drop generator; controlling a laser light source device to emit pulse laser and focus the pulse laser at a preset target shooting position in a vacuum environment within preset trigger time, and striking a target liquid drop to enable the target liquid drop to be subjected to laser acting force in a direction opposite to the movement direction of the target liquid drop so as to generate extreme ultraviolet light; controlling the droplet dissipation device to generate an alternating electric field to process the residual waste liquid of the target droplets after being hit by the pulse laser, and acquiring feedback information sent by the droplet dissipation device; and adjusting the working parameters of the laser light source device according to the feedback information. The extreme ultraviolet light generation method has the advantage of high energy conversion efficiency of the targeting laser.

Description

Extreme ultraviolet light generating method and device

Technical Field

The present disclosure relates to the field of Extreme Ultraviolet (EUV) light source technology, and more particularly, to a method and an apparatus for generating EUV light.

Background

With the continuous updating and upgrading of electronic products, the complexity of the internal circuit of the electronic product is continuously improved, and the integration level is higher and higher. The conventional Near Ultraviolet (NUV) and Deep Ultraviolet (DUV) light sources are gradually unable to meet the updating speed of electronic products. At present, the extreme ultraviolet light source is considered as the most promising lithography light source in the next generation of high-capacity integrated circuit manufacturing industry.

However, the traditional extreme ultraviolet light generation method impacts liquid drops from the side surface, is limited by the drop falling time of the liquid drops, has the problem of short laser action time, and is not beneficial to improving the energy conversion efficiency of the targeting laser. Therefore, the conventional extreme ultraviolet light generation method has a problem of low energy conversion efficiency of the targeting laser.

Disclosure of Invention

Therefore, the method and the device for generating the extreme ultraviolet light with high target laser energy conversion efficiency are provided to overcome the defects of the prior art.

A method of extreme ultraviolet light generation, comprising:

controlling a target droplet generator to generate target droplets;

determining preset trigger time according to the starting time of the target liquid drop generator;

controlling a laser light source device to emit pulse laser and focus the pulse laser at a preset target hitting position in a vacuum environment within the preset trigger time, and hitting the target liquid drop to enable the target liquid drop to be subjected to laser acting force in a direction opposite to the movement direction of the target liquid drop so as to generate extreme ultraviolet light;

controlling a liquid drop dissipating device to generate an alternating electric field to process the residual waste liquid of the target liquid drop after being hit by the pulse laser, and acquiring feedback information sent by the liquid drop dissipating device;

and adjusting the working parameters of the laser light source device according to the feedback information.

In one embodiment, the feedback information includes the amount and spatial distribution of remaining waste liquid, the laser light source device includes a laser and a beam delivery device, and the adjusting the operating parameters of the laser light source device according to the feedback information includes:

determining a new target shooting position according to the quantity and the spatial distribution of the residual waste liquid;

sending a direction adjusting instruction to the light beam transmission device according to the new target shooting position; and the direction adjusting instruction is used for controlling the light beam transmission device to change the transmission direction of the pulse laser and focus the pulse laser at a new target shooting position.

In one embodiment, the feedback information further includes a droplet dissipation efficiency, and after the controlling the droplet dissipation device to generate the alternating electric field to treat the residual waste liquid of the target droplet after the pulsed laser irradiation and obtaining the feedback information of the droplet dissipation device, the method further includes:

adjusting a parameter of the alternating electric field according to the droplet dissipation efficiency.

In one embodiment, the adjusting the parameter of the alternating electric field includes: adjusting the frequency and/or voltage of the alternating electric field.

In one embodiment, after the controlling the laser light source device to emit pulsed laser and focus the pulsed laser at a preset target position in a vacuum environment at the preset trigger time, radiate the target droplet, subject the target droplet to a laser force in a direction opposite to a moving direction of the target droplet, and generate extreme ultraviolet light, the method further includes:

acquiring detection data of extreme ultraviolet radiation energy, and sending early warning information to a terminal according to the detection data; the detection data is obtained by monitoring the extreme ultraviolet radiation energy reflected and focused by the light collector by an energy monitoring device and is sent to the controller.

An extreme ultraviolet light generating device comprises a controller, a target liquid drop generator, a laser light source device and a liquid drop dissipating device; the target liquid drop generator, the laser light source device and the liquid drop dissipation device are respectively connected with the controller;

the target liquid drop generator is used for generating target liquid drops according to a control instruction of the controller;

the laser light source device is used for emitting pulse laser, focusing the pulse laser at a preset target hitting position in a vacuum environment, hitting the target liquid drop, and enabling the target liquid drop to be subjected to laser acting force in a direction opposite to the movement direction of the target liquid drop to generate extreme ultraviolet light;

the liquid drop dispersing device is used for generating an alternating electric field to process the residual waste liquid of the target liquid drops after being hit by the pulse laser and sending feedback information to the controller;

the controller is used for obtaining the preset trigger time according to the starting time of the target liquid drop generator and controlling the laser light source device to emit the pulse laser within the preset trigger time; the controller is also used for adjusting the working parameters of the laser light source device according to the feedback information after the pulsed laser irradiates the target liquid drop.

In one embodiment, the laser light source device comprises a laser and a light beam transmission device; the laser and the light beam transmission device are connected with the controller.

In one embodiment, the number of the laser light source devices is multiple, and the transmission directions of the pulse lasers generated by the multiple sets of laser light source devices are distributed in an array by taking the movement direction of the target liquid drop as a symmetry axis.

In one embodiment, the droplet dissipater includes an alternating current power source and an electrode plate, the alternating current power source connecting the electrode plate and the controller.

In one embodiment, the extreme ultraviolet light generating device further comprises a light collector and an energy monitoring device, wherein the energy monitoring device is connected with the controller;

the light collector is used for reflecting and focusing the extreme ultraviolet light; the energy monitoring device is used for monitoring the extreme ultraviolet radiation energy reflected and focused by the light collector and sending detection data of the extreme ultraviolet radiation energy to the controller;

and the controller is also used for sending early warning information to the terminal according to the detection data.

According to the extreme ultraviolet light generation method, firstly, after the target liquid drop generator generates the target liquid drop, the laser light source device is controlled to emit the pulse laser and focus the pulse laser on the target position within the preset trigger time according to the starting time of the target liquid drop generator, and the waste of the energy of the pulse laser before the target liquid drop is not generated can be avoided. Secondly, when the pulse laser hits the target liquid drop, the acting time of the pulse laser can be increased because the acting force of the laser is opposite to the moving direction of the target liquid drop. And thirdly, the liquid drop dispersing device is controlled to generate an alternating electric field to process the residual waste liquid of the target liquid drops after being hit by the pulse laser, so that the pollution of the residual waste liquid to each element is favorably reduced, the extreme ultraviolet light radiation efficiency is favorably improved, and the service life of each element is prolonged. And finally, obtaining feedback information sent by the liquid drop dissipating device, and adjusting working parameters of the laser light source device according to the feedback information, namely adding a feedback adjustment mode, and adjusting parameters of the targeting laser according to the current actual state. The methods are mutually matched, and the target-shooting laser energy utilization rate is favorably improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of a method for extreme ultraviolet light generation in one embodiment;

FIG. 2 is a flow chart illustrating adjusting the operating parameters of the laser source device according to the feedback information according to an embodiment;

FIG. 3 is a flow chart of a method for generating extreme ultraviolet light in another embodiment;

fig. 4 is a block diagram of an extreme ultraviolet light generating device provided in one embodiment;

fig. 5 is a schematic structural diagram of an extreme ultraviolet light generating device provided in another embodiment.

Description of the reference numerals: 10-controller, 20-target droplet generator, 21-target droplet, 22-residual waste liquid of target droplet, 30-laser light source device, 31-pulse laser, 40-droplet dissipation device, 41-alternating current power supply, 421-first electrode plate, 422-second electrode plate, 50-light collector, 60-energy monitoring device and F-preset targeting position.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. In addition, "connection" in the following embodiments is understood as "optical connection" if there is transmission of an optical signal between connected objects.

In an embodiment, referring to fig. 1, a method for generating extreme ultraviolet light is provided, which includes steps S10 to S50.

Step S10: controlling the target droplet generator to generate the target droplets.

Specifically, the controller sends a control instruction to the target droplet generator to control the target droplet generator to generate the target droplets. The control instructions may be used to control the frequency, size, and initial velocity of generation of the target droplets. For example, the controller may send control instructions to the target droplet generator based on the frequency of the targeting laser, adjust parameters of the target droplet generator to control the target droplet generation frequency to match the frequency of the targeting laser, and control the target droplet generation size to match the focal spot size of the targeting laser. Further, the generation frequency of the target droplet is matched with the frequency of the targeting laser, which may mean that the generation frequency of the target droplet is the same as the frequency of the targeting laser, or that the generation frequency of the target droplet is an integral fraction of the frequency of the targeting laser.

Further, the process of the target droplet generator generating the target droplets may be: the solid target is heated to enable the temperature to be higher than the melting point, and then pressure is applied to enable target liquid drops to pass through a filter and reach a nozzle to be sprayed out, so that a target liquid drop string with uniform size and stable frequency is generated. The process of generating target droplets by the target droplet generator may also be: the method comprises the steps that a solid target with a preset specification moves along a preset path under the driving of an external force field, in the moving process of the solid target, a limiting device is adopted to limit the passing frequency of the solid target, a non-contact heating mode is adopted, such as electromagnetic heating, the solid target is melted to generate target liquid drops, and then the target liquid drops are driven to move to a target shooting laser focusing point along the preset path under the premise that the target liquid drops are not in contact with any part of a target liquid drop generator through the external force field. In summary, the present embodiment does not limit the specific operation process of the target droplet generator.

The target droplets may be metallic droplets or non-metallic droplets. In one embodiment, the target droplet is a tin droplet. The source of extreme ultraviolet radiation of the tin target at the wavelength of 13.5nm mainly depends on high valence state ions Sn of tin in plasma ⁸⁺ ～Sn ¹³⁺ Is formed. The morphology and purity of the tin target can affect the extreme ultraviolet conversion efficiency to some extent. The higher the tin content in the tin target, the higher the euv conversion efficiency. The liquid drop tin is adopted as a target, a target cloud generated by the liquid drop tin under the irradiation of the pre-pulse laser can be gasified by the main pulse laser, the EUV radiation efficiency generated by the liquid drop tin can reach 3.4 percent and is far higher than that of a solid target, and the energy utilization rate of the target laser can be further improved.

Step S20: and determining preset trigger time according to the starting time of the target liquid drop generator.

The target droplet has a certain initial velocity after it has left the target droplet generator. When no external force field acts, the target liquid drop keeps the preset initial speed to move at a constant speed along the initial speed direction, and the time required by the target liquid drop to move from the outlet of the target liquid drop generator to the target position can be determined according to the spatial relationship between the target liquid drop generator and the target position. When an external force field acts, the motion speed and the motion trail of the target liquid drop can be determined according to the initial speed and the size and the direction of the external force field, and the time required by the target liquid drop to move from the outlet of the target liquid drop generator to the target position can also be determined by combining the spatial relationship between the target liquid drop generator and the target position. In combination with the activation time of the target drop generator, the preset trigger time can be determined. For convenience of understanding, the following description will take the example that the preset initial velocity direction coincides with the gravity direction, and the target liquid droplet performs free-fall motion under the action of the gravity field.

Furthermore, a droplet detection device can be arranged on the motion path of the target droplet to detect the target droplet reaching the detection point, obtain a detection signal and send the detection signal to the controller, and the controller further corrects the preset trigger time according to the detection signal to ensure that the target droplet meets the pulse laser at the preset targeting position.

Step S30: and controlling a laser light source device to emit pulse laser and focus the pulse laser at a preset target hitting position in a vacuum environment within preset trigger time, and hitting the target liquid drop to enable the target liquid drop to be subjected to laser acting force in a direction opposite to the moving direction of the target liquid drop so as to generate extreme ultraviolet light.

Wherein, the vacuum environment can be a vacuum cavity, and a vacuum pump is used for pumping air in the cavity to ensure the vacuum degree of the cavity. The laser light source device comprises a laser and a light beam transmission device, wherein the laser is used for generating pulse laser, and the light beam transmission device is used for determining the transmission direction of the pulse laser and focusing the pulse laser on a preset target-hitting position. The light beam transmission device comprises an optical assembly and a focusing assembly, wherein the optical assembly comprises a lens and a reflector, and the focusing assembly comprises a focusing lens. The impact is not an impact action in the conventional sense, but the entire process of the pulsed laser acting on the target droplet to cause it to change. The controller controls the laser light source device to emit the pulse laser within a preset trigger time, the controller can control the laser light source device to emit the pulse laser within the preset trigger time, or the controller can send the preset trigger time to the laser light source device, and the laser light source device emits the pulse laser according to the preset trigger time.

In one embodiment, the number of the laser light source devices is one set, and the position and the angle of each optical element in the light beam transmission device are adjusted, so that the pulse laser emitted by the laser is focused at a preset target shooting position along the direction opposite to the movement direction of the target liquid drop, and a laser energy field taking a focus as the center is formed. After the target liquid drop reaches the laser energy field, the target liquid drop is deformed into a flat shape under the action of laser acting force opposite to the self-movement direction, and the volume of the target liquid drop is increased; the flattened target liquid drop continues to move towards the center of the laser energy field, namely the focus, continues to be plasmatized under the action of the laser, and generates extreme ultraviolet light when reaching the threshold value for generating extreme ultraviolet radiation.

In another embodiment, the number of the laser light source devices is multiple, and the transmission directions of the pulse lasers generated by the multiple sets of laser light source devices are distributed in an array by taking the movement direction of the target liquid drop as a symmetry axis. By adjusting the position and angle of each optical element in each beam transmission device and performing time sequence control on each laser, the multi-path pulse laser emitted by each laser can be focused on a preset target-hitting position at the same time to form a laser energy field taking a focus as a center. After the target liquid drops reach the laser energy field, the target liquid drops are simultaneously hit by multi-path pulse laser, the resultant force of the acting force of the laser is opposite to the self moving direction, the target liquid drops are deformed into a flat shape, and the size of the target liquid drops is increased; the flattened target liquid drop continues to move towards the center of the laser energy field, namely the focus, continues to be plasmatized under the action of the laser, and generates extreme ultraviolet light when reaching the threshold value for generating extreme ultraviolet radiation. The number of the laser light source devices can be four, four paths of pulse lasers are generated and are simultaneously focused on the preset target hitting positions to hit target liquid drops.

Step S40: and controlling the droplet dissipation device to generate an alternating electric field to process the residual waste liquid of the target droplets after being hit by the pulse laser, and acquiring feedback information sent by the droplet dissipation device.

Specifically, the target liquid drop is changed into a plasma state after being hit at a preset target hitting position, and the residual waste liquid of the target liquid drop is composed of different plasma groups with random charge-to-mass ratios. And the residual waste liquid of the target liquid drops continuously falls to the liquid drop dissipation device below the preset targeting position. All the plasmoids reciprocate within a certain range under the action of an alternating electric field in the liquid drop dispersing device. Because the charge-to-mass ratio distribution of the plasmoid is irregular, the reciprocating track is also irregular, and the plasmoids with positive charges and negative charges collide with each other, so that the plasma dissipation phenomenon can occur. Further, the droplet dissipater may send feedback to the controller. The feedback information may include the amount and spatial distribution of remaining waste.

Step S50: and adjusting the working parameters of the laser light source device according to the feedback information.

The working parameter of the laser light source device may refer to the energy of the pulse laser or a preset trigger time. Specifically, according to the feedback information, the controller may determine the condition of the remaining waste liquid after the previous impact, and when the remaining waste liquid is large, it indicates that the pulsed laser and the target droplet do not completely act, so that the reason for such a result may be that the target droplet and the time node at which the pulsed laser reaches the preset targeting position are not matched, or the energy of the pulsed laser is insufficient. At this time, the preset trigger time or the pulse laser energy is adjusted, so that the extreme ultraviolet radiation efficiency is improved.

According to the extreme ultraviolet light generation method, firstly, after the target liquid drop generator generates the target liquid drop, the laser light source device is controlled to emit the pulse laser and focus the pulse laser on the target position within the preset trigger time according to the starting time of the target liquid drop generator, and the waste of the energy of the pulse laser before the target liquid drop is not generated can be avoided. Secondly, when the pulse laser hits the target liquid drop, the acting time of the pulse laser can be increased because the acting force of the laser is opposite to the moving direction of the target liquid drop. And thirdly, the liquid drop dispersing device is controlled to generate an alternating electric field to process the residual waste liquid of the target liquid drop after being hit by the pulse laser, so that the pollution of the residual waste liquid to each element is reduced, the extreme ultraviolet radiation efficiency is improved, and the service life of each element is prolonged. And finally, acquiring feedback information sent by the liquid drop dissipation device, and adjusting working parameters of the laser light source device according to the feedback information, namely adding a feedback adjustment mode, and adjusting parameters of the targeting laser according to the current actual state. The methods are mutually matched, and the target-shooting laser energy utilization rate is favorably improved.

In one embodiment, the feedback information includes the amount and spatial distribution of the remaining waste liquid, the laser source device includes a laser and a beam delivery device, and referring to fig. 2, step S50 includes step S51 and step S52.

Step S51: and determining a new target shooting position according to the quantity and the spatial distribution of the residual waste liquid.

Under the condition that the generation frequency of the target liquid drops is determined, the quantity of the target liquid drops generated by the target liquid drop generator is constant in unit time, and the change condition of the quantity of the newly added waste liquid in the liquid drop dissipation device can reflect the change condition of the extreme ultraviolet radiation efficiency to a certain extent. That is, the increase in the amount of newly added waste liquid is accompanied by a decrease in the efficiency of extreme ultraviolet radiation. Of course, the amount of waste liquid herein, not only refers to the number of waste liquid, but also includes the volume and weight of waste liquid, and is a comprehensive index for measuring the change of waste liquid. The controller can also judge the working condition of the system according to the quantity of the newly added waste liquid fed back by the liquid drop dissipating device, if the quantity of the newly added waste liquid is higher than a preset threshold value, the parameter of each component in the extreme ultraviolet light generating device needs to be optimized, at the moment, the controller sends early warning information to the terminal to remind a terminal worker of maintaining equipment in time, stable extreme ultraviolet radiation efficiency is maintained, and the energy utilization rate of the targeting laser is improved.

Further, the usage of the target droplet can be determined from a spatial perspective. As described above, the pulsed laser is focused at the preset target position in the vacuum environment, i.e. the center of the target laser focal spot is the preset target position. When the target liquid drop is coincident with the center of a target laser focal spot, the residual waste liquid is uniformly distributed by taking the projection of the target position along the movement direction of the target liquid drop as the center. When the target liquid drop and the center of a target laser focal spot have deviation, the laser acting force on one side deviated from the center of the focal spot is small, the radiation is incomplete, and the quantity of the residual waste liquid is inevitably larger than that on the other side. Therefore, the controller can reversely deduce the position of the target liquid drop under the action of the pulse laser according to the spatial distribution of the waste liquid on the liquid drop dissipating device, and further calculate the deviation between the target liquid drop and the focal spot center of the pulse laser. And judging whether the target hitting position needs to be updated or not by combining the quantity of the newly added waste liquid. And if the number of the newly added waste liquid is higher than the preset threshold value, determining a new target shooting position according to the spatial distribution of the newly added waste liquid.

Step S52: and sending a direction adjusting instruction to the light beam transmission device according to the new target shooting position.

The direction adjusting instruction is used for controlling the light beam transmission device to change the transmission direction of the pulse laser and focus the pulse laser at a new target position. Specifically, the light beam transmission device comprises an optical assembly and a focusing assembly, wherein the optical assembly comprises a lens and a reflector, and the focusing assembly comprises a focusing lens. The transmission direction of the pulse laser is determined by the positions and angles of the lens and the mirror. For automatic control, in one embodiment, the position and the angle of the last reflecting mirror on the optical path are adjusted to change the transmission direction of the pulse laser, so that the pulse laser is focused on a new target position.

In the above embodiment, when the target droplet has a deviation from the preset targeting position and the target droplet utilization rate is low, the controller determines a new targeting position according to the spatial distribution of the newly added waste liquid in the droplet dissipation device, and controls the beam delivery device to focus the pulse laser at the new targeting position, which is beneficial to improving the energy utilization rate of the targeting laser.

In another embodiment, the feedback information further includes a droplet dissipation efficiency, and referring to fig. 3, after step S40, further includes step S60: parameters of the alternating electric field are adjusted according to the droplet dissipation efficiency. It is understood that step S60 may be performed before or after step S50, or may be performed simultaneously with step S50.

Wherein, the liquid drop dissipation efficiency refers to the ratio of the amount of liquid drops dissipated in the liquid drop dissipation device to the amount of liquid drops entering the liquid drop dissipation device. Specifically, an efficiency threshold may be set for the droplet dissipation efficiency, and the efficiency threshold may be a single value or a range of values. When the efficiency threshold is a single value, if the droplet dissipation efficiency is lower than the efficiency threshold, the residual plasma may affect subsequent targeting, and the controller adjusts the parameters of the alternating electric field to improve the droplet dissipation efficiency. When the efficiency threshold is a numerical range: if the liquid drop dissipation efficiency is lower than the minimum value of the efficiency threshold value, the residual plasma can possibly influence the subsequent target practice, and the controller adjusts the parameters of the alternating electric field to improve the liquid drop dissipation efficiency; if the droplet dissipation efficiency is above the maximum of the efficiency threshold, indicating that the droplet dissipation efficiency is too high, and there may be a waste of energy from the alternating electric field, the controller adjusts the parameters of the alternating electric field to decrease the droplet dissipation efficiency.

In one embodiment, adjusting a parameter of the alternating electric field comprises: the frequency and/or voltage of the alternating electric field is adjusted.

Specifically, the higher the frequency of the alternating electric field is, the more frequent the plasma groups reciprocate, the higher the probability of collision is, and the better the dissipation effect is; the larger the voltage of the alternating electric field is, the faster the moving speed of each plasmoid is, and the better the dissipation effect after collision is. That is, by increasing the frequency and/or voltage of the alternating electric field, the efficiency and effectiveness of plasma dissipation can be increased; by reducing the frequency and/or voltage of the alternating electric field, the efficiency and effectiveness of plasma dissipation may be reduced.

In the above embodiment, the parameter adjustment of the alternating electric field is performed according to the droplet dissipation efficiency fed back by the droplet dissipation device, so that the plasma cluster can be dissipated under the action of the alternating electric field, the pulsed laser can be ensured to successfully reach the preset targeting position to act with the next target droplet, and the stability of the system can be maintained.

In an embodiment, with continuing reference to fig. 3, after step S30, step S70 is further included: and acquiring detection data of the extreme ultraviolet radiation energy, and sending early warning information to the terminal according to the detection data. It is understood that step S70 may be performed before or after step S50, or may be performed simultaneously with step S50. Similarly, step S70 may be performed before or after step S60, or may be performed simultaneously with step S60.

The detection data are obtained by monitoring the extreme ultraviolet radiation energy reflected and focused by the light collector by the energy monitoring device and are sent to the controller. The light collector is a device with a certain shape and a light reflecting surface. In order to improve the focusing effect of the extreme ultraviolet light, the shape of the light collector may be designed to be a circular arc, and a reflective coating or a grating pattern may be further added to the light reflecting surface to improve the reflecting and focusing effects. Specifically, after the pulsed laser strikes the target droplet to generate the extreme ultraviolet light, the extreme ultraviolet light is collected by the light collector to the energy monitoring device. The extreme ultraviolet radiation energy of specific time nodes is monitored through an energy monitoring device, and detection data are sent to a controller. The controller judges the change condition of the extreme ultraviolet radiation efficiency according to the detection data. If the extreme ultraviolet radiation efficiency is lower than the preset threshold value, the parameter of each component in the extreme ultraviolet light generating device needs to be optimized, at the moment, the controller sends early warning information to the terminal to remind a terminal worker of maintaining equipment in time, stable extreme ultraviolet radiation efficiency is maintained, and the energy utilization rate of the targeting laser is improved.

In addition, after a certain time, the reflection surface of the light collector is affected by various factors such as particle aggregation, ion damage, bubbling and oxidation, and the reflectivity thereof is reduced to some extent, which inevitably affects the final energy of the extreme ultraviolet radiation. The present embodiment can ensure that the system is in a relatively balanced and efficient state by continuously cycling through "feedback-control". When the system is in the state that the extreme ultraviolet radiation efficiency is higher and the target liquid drop utilization ratio is higher, the amount of debris that the system produced must be less to can avoid the plane of reflection of light collector to be polluted to a certain extent, increase the life of light collector, improve collection, reflection and the focus effect of light collector to extreme ultraviolet light.

It should be understood that, although the respective steps in the flowcharts referred to in the above embodiments are sequentially shown as indicated by arrows, the steps are not necessarily performed sequentially as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a part of the steps in each flowchart involved in the above embodiments may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the steps or stages is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a part of the steps or stages in other steps.

In one embodiment, referring to fig. 4, an extreme ultraviolet light generating device is provided, which includes a controller 10, a target droplet generator 20, a laser light source device 30, and a droplet dissipating device 40; the target droplet generator 20, the laser light source device 30 and the droplet dissipation device 40 are connected to the controller 10, respectively. The target liquid drop generator 20 is used for generating target liquid drops according to a control instruction of the controller 10; the laser light source device 30 is used for emitting pulse laser, focusing the pulse laser at a preset target hitting position in a vacuum environment, hitting the target liquid drop, and enabling the target liquid drop to be subjected to laser acting force in a direction opposite to the moving direction of the target liquid drop to generate extreme ultraviolet light; the droplet dissipation device 40 is used for generating an alternating electric field to process the residual waste liquid of the target droplets after being hit by the pulsed laser, and sending feedback information to the controller 10; the controller 10 is configured to obtain a preset trigger time according to the start time of the target droplet generator 20 and control the laser light source device 30 to emit the pulsed laser at the preset trigger time; the controller 10 is also configured to adjust the operating parameters of the laser source device 30 based on the feedback information after the pulsed laser irradiates the target droplet.

Specifically, referring to fig. 4, the target droplets 21 generated by the target droplet generator 20 have a certain initial velocity when they are separated from the target droplet generator 20. On the one hand, the target droplet 21 continues to fall under the action of the gravity field to reach the point F of the preset target-hitting position. On the other hand, the controller 10 determines the movement speed and the movement trajectory of the target droplet 21 according to the preset initial speed and the gravitational acceleration, and obtains the time required for the target droplet 21 to move from the outlet of the target droplet generator 20 to the point F of the target position by combining the spatial relationship between the target droplet generator 20 and the point F of the target position. And determining a preset trigger time by combining the starting time of the target droplet generator 20, and controlling the laser light source device 30 to emit the pulse laser 31 and focus the pulse laser 31 on a preset target-hitting position F point in the vacuum environment at the preset trigger time. In this way, the object droplet 21 and the pulsed laser 31 meet at the preset target position F, and the pulsed laser 31 strikes the object droplet 21, so that the object droplet 21 receives a laser force in the direction opposite to the movement direction of the object droplet 21, and generates extreme ultraviolet light.

In one embodiment, the laser light source device 30 includes a laser and a beam delivery device; the laser and beam delivery device are connected to a controller 10. The laser is used for generating pulse laser, and the beam delivery device is used for determining the transmission direction of the pulse laser and focusing the pulse laser on a preset target-hitting position. The light beam transmission device comprises an optical assembly and a focusing assembly, wherein the optical assembly comprises a lens and a reflector, and the focusing assembly comprises a focusing lens.

The target droplets 21 are struck and converted into a plasma state, and the remaining waste liquid 22 of the target droplets is composed of different plasmoids with random charge-to-mass ratios. The remaining waste stream 22 of targeted droplets continues to fall to the droplet dissipation device 40 below the predetermined target location F. All the plasmoids reciprocate within a certain range under the action of the alternating electric field in the droplet dissipation device 40. The charge-to-mass ratio distribution of the plasma clusters is irregular, so that the reciprocating motion track is also irregular, and the plasma clusters with positive and negative charges collide with each other, so that the plasma dissipation phenomenon can occur.

In one embodiment, referring to FIG. 5, droplet dissipation device 40 includes an AC power source 41 and electrode plates, where AC power source 41 is connected to electrode plates and controller 10. Specifically, the first electrode plate 421 and the second electrode plate 422 are respectively connected to two ends of the ac power supply 41, and after the ac power is supplied, an alternating electric field is generated between the first electrode plate 421 and the second electrode plate 422, and an action area of the alternating electric field is located below the point F of the preset targeting position.

Further, droplet dissipater 40 may also send feedback to controller 10. Based on the feedback information, the controller 10 may determine the remaining waste liquid after the previous impact, and when the remaining waste liquid is large, it indicates that the pulsed laser 31 and the target droplet 21 do not completely act, and the reason for this may be that the target droplet 21 and the pulsed laser 31 reach the preset target position F at a non-matching time node, or the energy of the pulsed laser 31 is insufficient. At this time, the controller 10 is beneficial to improving the extreme ultraviolet radiation efficiency by adjusting the preset trigger time or the pulse laser energy.

After the target droplet generator 20 generates the target droplet 21, the controller 10 controls the laser light source device 30 to emit the pulse laser 31 and focus the pulse laser 31 on the target position F according to the start time of the target droplet generator 10, so as to avoid the waste of energy of the pulse laser before the target droplet 21 is not generated. Secondly, when the pulsed laser 31 strikes the target droplet 21, the action time of the pulsed laser 31 can be increased because the action force of the laser is opposite to the movement direction of the target droplet. And thirdly, the droplet dissipating device 50 generates an alternating electric field to treat the residual waste liquid 22 of the target droplet after being hit by the pulse laser 31, which is beneficial to reducing the pollution of the residual waste liquid to each element, improving the radiation efficiency of the extreme ultraviolet light and prolonging the service life of each element. Finally, the controller 10 obtains the feedback information sent by the droplet dissipating device 40, and adjusts the working parameters of the laser source device 30 according to the feedback information, which is equivalent to adding a feedback adjustment mode, and can adjust the parameters of the targeting laser according to the current actual state. The methods are mutually matched, and the target-shooting laser energy utilization rate is favorably improved.

In one embodiment, the number of the laser light source devices is one set, and the pulse laser emitted by the laser is focused at a preset target-hitting position along the opposite direction of the movement direction of the target liquid drop by adjusting the position and the angle of each optical element in the light beam transmission device, so that a laser energy field taking a focus as a center is formed. After the target liquid drop reaches the laser energy field, the target liquid drop is deformed into a flat shape under the action of laser acting force opposite to the self-movement direction, and the volume of the target liquid drop is increased; the flattened target liquid drops continue to move towards the center of the laser energy field, namely the focus, continue to be ionized under the action of the laser, and generate extreme ultraviolet light when reaching the threshold value for generating extreme ultraviolet radiation.

In the embodiment, the transmission direction of the pulse laser is designed, so that the acting force of the pulse laser on the target liquid drop is opposite to the movement direction of the target liquid drop, the acting time of the pulse laser is prolonged, and the utilization rate of the targeting laser is improved; the method promotes the target liquid drops to generate pie-shaped deformation, enlarges the volume, improves the uniformity of the pie-shaped plasma formation, is favorable for generating better extreme ultraviolet radiation, and is favorable for improving the energy conversion efficiency of the system.

In another embodiment, the number of the laser light source devices is multiple, and the transmission directions of the pulse lasers generated by the multiple sets of laser light source devices are distributed in an array by taking the movement direction of the target liquid drop as a symmetry axis. By adjusting the position and angle of each optical element in each beam transmission device and performing time sequence control on each laser, the multi-path pulse laser emitted by each laser can be focused on a preset target-hitting position at the same time to form a laser energy field taking a focus as a center. After the target liquid drops reach the laser energy field, the target liquid drops are simultaneously hit by the multi-channel pulse laser, the resultant force of the acting force of the laser is opposite to the self-moving direction, the target liquid drops are deformed into a flat shape, and the size of the target liquid drops is increased; the flattened target liquid drops continue to move towards the center of the laser energy field, namely the focus, continue to be ionized under the action of the laser, and generate extreme ultraviolet light when reaching the threshold value for generating extreme ultraviolet radiation. The number of the laser light source devices can be four, four paths of pulse lasers are generated and are simultaneously focused on the preset target hitting positions to hit target liquid drops.

In this embodiment, by focusing multiple sets of pulse lasers generated by the laser light source devices on the same focus and striking target droplets meeting with the same focus, in practical applications, when the output energy of one laser is insufficient, the number of the lasers can be increased appropriately, and the striking directions of the pulse lasers emitted by the lasers can be designed reasonably, so that the target droplets are subjected to plasma change, and further required extreme ultraviolet light can be generated. In addition, the design of a plurality of sets of laser light source devices ensures that the transmission path of each path of pulse laser and the movement direction of the target liquid drop are not strictly reverse but form an angle, thus reducing the influence of residual waste liquid after the previous target shooting and improving the energy utilization rate of the target shooting laser.

The matching modes of various laser light source devices are provided, and the flexibility of the application scene of the extreme ultraviolet light generating device is favorably improved.

In one embodiment, with continued reference to fig. 5, the euv light generating device further comprises a light collector 50 and an energy monitoring device 60, wherein the energy monitoring device 60 is connected to the controller 10. Light collector 50 is used to reflect and focus extreme ultraviolet light; the energy monitoring device 60 is configured to monitor the euv radiation energy reflected and focused by the light collector 50, and send detection data of the euv radiation energy to the controller 10; the controller 10 is also configured to send warning information to the terminal according to the detection data.

Specifically, the light collector 50 is a device having a predetermined shape and a light reflecting surface. To improve the focusing effect of the euv light, the light collector 50 may be shaped as a circular arc, and a reflective coating or a grating pattern may be further added to the light reflecting surface to improve the reflecting and focusing effects. Specifically, after the pulsed laser 31 strikes the target droplet 21 to generate euv light, the euv light is collected by the light collector 50 to the energy monitoring device 60. The euv radiation energy at a specific time node is monitored by the energy monitoring device 60 and the detected data is sent to the controller 10. The controller 10 determines the change of the euv radiation efficiency based on the detection data. If the extreme ultraviolet radiation efficiency is lower than the preset threshold value, the parameters of all components in the extreme ultraviolet light generating device need to be optimized, at the moment, the controller 10 sends early warning information to the terminal to remind a terminal worker of maintaining equipment in time, stable extreme ultraviolet radiation efficiency is maintained, and the energy utilization rate of the targeting laser is improved.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A method of producing extreme ultraviolet light, comprising:

controlling a target droplet generator to generate target droplets;

determining preset trigger time according to the starting time of the target liquid drop generator;

controlling a laser light source device to emit pulse laser within the preset trigger time, focusing the pulse laser at a preset target hitting position in a vacuum environment, hitting the target liquid drop, and enabling the target liquid drop to be subjected to laser acting force in a direction opposite to the moving direction of the target liquid drop to generate extreme ultraviolet light;

controlling a liquid drop dispersing device to generate an alternating electric field to process the residual waste liquid of the target liquid drops after the liquid drop dispersing device is hit by the pulse laser, and acquiring feedback information sent by the liquid drop dispersing device; the feedback information comprises the quantity and spatial distribution of the remaining waste liquid;

calculating the position deviation between the focal spot center of the pulse laser and the target liquid drop when the target liquid drop and the pulse laser act according to the spatial distribution of the residual waste liquid; when the quantity of the residual waste liquid is higher than a preset threshold value, adjusting the preset trigger time or the energy of the pulse laser based on the quantity of the residual waste liquid, and determining a new preset target shooting position according to the position deviation; the amount of the remaining spent liquor comprises the volume and weight of the remaining spent liquor.

2. The extreme ultraviolet light generating method as recited in claim 1, wherein the laser light source device comprises a laser and a beam delivery device, the method further comprising:

sending a direction adjusting instruction to the light beam transmission device according to the new target shooting position; and the direction adjusting instruction is used for controlling the light beam transmission device to change the transmission direction of the pulse laser and focus the pulse laser at a new target shooting position.

3. The extreme ultraviolet light generating method as claimed in claim 2, wherein the feedback information further includes a droplet dissipation efficiency, and after the controlling the droplet dissipation device to generate the alternating electric field to treat the residual waste liquid of the target droplet after the pulsed laser irradiation and obtaining the feedback information of the droplet dissipation device, the method further includes:

adjusting a parameter of the alternating electric field according to the droplet dissipation efficiency.

4. The extreme ultraviolet light generating method as claimed in claim 3, wherein the adjusting the parameter of the alternating electric field comprises: adjusting the frequency and/or voltage of the alternating electric field.

5. The euv light generation method according to any one of claims 1 to 4, wherein the controlling the laser light source device to emit a pulsed laser and focus the pulsed laser at a preset target position in a vacuum environment at the preset trigger time, to irradiate the target droplet, so that the target droplet is subjected to a laser force in a direction opposite to a movement direction of the target droplet, and after the generation of the euv light, further comprises:

acquiring detection data of extreme ultraviolet radiation energy, and sending early warning information to a terminal according to the detection data; the detection data is obtained by monitoring the extreme ultraviolet radiation energy reflected and focused by the light collector by the energy monitoring device and is sent to the controller.

6. An extreme ultraviolet light generating device is characterized by comprising a controller, a target liquid drop generator, a laser light source device and a liquid drop dissipating device; the target liquid drop generator, the laser light source device and the liquid drop dissipation device are respectively connected with the controller;

the target liquid drop generator is used for generating target liquid drops according to a control instruction of the controller;

the laser light source device is used for emitting pulse laser, focusing the pulse laser at a preset target hitting position in a vacuum environment, hitting the target liquid drop, and enabling the target liquid drop to be subjected to laser acting force in a direction opposite to the movement direction of the target liquid drop to generate extreme ultraviolet light;

the liquid drop dissipating device is used for generating an alternating electric field to process the residual waste liquid of the target liquid drop after being hit by the pulse laser and sending feedback information to the controller; the feedback information comprises the quantity and spatial distribution of the remaining waste liquid;

the controller is used for obtaining preset trigger time according to the starting time of the target liquid drop generator and controlling the laser light source device to emit the pulse laser within the preset trigger time; the controller is also used for calculating the position deviation of the focal spot center of the pulse laser and the target liquid drop when the target liquid drop and the pulse laser act according to the spatial distribution of the residual waste liquid after the pulse laser irradiates the target liquid drop; when the quantity of the residual waste liquid is higher than a preset threshold value, adjusting the preset trigger time or the energy of the pulse laser based on the quantity of the residual waste liquid, and determining a new preset target shooting position according to the position deviation; the amount of the remaining spent liquor comprises the volume and weight of the remaining spent liquor.

7. The extreme ultraviolet light generating device as claimed in claim 6, wherein the laser light source device comprises a laser and a light beam transmission device; the laser and the light beam transmission device are connected with the controller.

8. The extreme ultraviolet light generating device according to claim 6, wherein the number of the laser light source devices is plural, and the transmission direction of each pulse laser generated by each laser light source device is distributed in an array with the movement direction of the target droplet as a symmetry axis.

9. The extreme ultraviolet light generating device of claim 6, wherein the droplet dissipating device comprises an alternating current power source and an electrode plate, the alternating current power source connecting the electrode plate and the controller.

10. The euv light generating device according to any one of claims 6 to 9, further comprising a light collector and an energy monitoring device, wherein the energy monitoring device is connected to the controller;

the light collector is used for reflecting and focusing the extreme ultraviolet light; the energy monitoring device is used for monitoring the extreme ultraviolet radiation energy reflected and focused by the light collector and sending detection data of the extreme ultraviolet radiation energy to the controller;

and the controller is also used for sending early warning information to the terminal according to the detection data.

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