Regulation and control method and system for moving track of metal liquid drop and extreme ultraviolet light source system

Abstract

The invention relates to the technical field of photoetching machines, and discloses a method and a system for regulating and controlling a moving track of a metal droplet, and an extreme ultraviolet light source system. The regulation and control method comprises the steps that metal liquid drops generated by a liquid drop generator are charged, so that the metal liquid drops are electrified; detecting the moving track of the charged metal liquid drop to obtain a position signal of the metal liquid drop; according to the position signal, whether the metal liquid drop is located on a preset moving track or not is judged, and if the metal liquid drop deviates from the preset moving track, a deflection electric field and / or a magnetic field where the metal liquid drop is located are / is adjusted, and the metal liquid drops return to the preset moving track under the action of the deflection electric field and / or the magnetic field. The regulation and control method provided by the invention belongs to closed-loop advanced control, and the liquid drops are accurately regulated and controlled in real time according to the liquid drop position signals. Therefore, the liquid drops accurately reach the laser focus. And the precision and the efficiency of liquid drop control are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photolithography machines, and in particular to a method and system for regulating the trajectory of a metal droplet, and an extreme ultraviolet light source system. Background Art

[0002] The most advanced lithography machine is based on an EUV (extreme ultraviolet) light source with a wavelength of 13.5nm. Compared with the previous generation of deep ultraviolet lithography machines, the wavelength of the EUV light source is shortened to 1 / 14, which greatly improves the lithography resolution of a single exposure and can significantly increase production rate and yield.

[0003] The EUV light source used for chip manufacturing and testing is based on laser-induced plasma (LPP) technology. The working principle of LPP technology is to generate a uniform high-frequency tin droplet target in a vacuum environment, use picosecond or nanosecond laser as a pre-pulse to bombard the droplets to spread them into a liquid film, and then use nanosecond pulse laser to bombard the liquid film to fully ionize it to produce plasma, and the plasma releases extreme ultraviolet light with a wavelength of 13.5nm. Due to the mechanical instability of the droplet generation process and external disturbances, the tin droplets generated by the droplet generator inevitably have a certain degree of jitter. The droplets deviate from the laser focus due to jitter, which will make the laser unable to accurately focus on the bombardment of the tin droplets, resulting in insufficient interaction between the laser and the tin droplets and unstable output EUV light.

[0004] The common technology at present is to achieve control through laser steering or droplet generator steering. However, steering control is a hysteresis regulation. The laser and droplet generator have a large mass, which means that they need to overcome a large inertia force when performing steering operations, which not only increases the burden on the drive system and reduces the response speed, but also may cause delays and errors in the steering process.

[0005] Therefore, the prior art needs to be further improved and enhanced. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method and system for controlling the trajectory of metal droplets and an extreme ultraviolet light source system. The purpose is to charge the metal droplets, detect the trajectory of the droplets, and perform advance control on the trajectory of the droplets based on the detection results, so that the droplets can be controlled before they reach the laser position, so that the droplets can accurately reach the laser focus. Since the mass of the droplets is very small and the response time is short, the deficiencies of the prior art are effectively solved, and the accuracy and efficiency of droplet control are improved.

[0007] The above object of the present invention is achieved through the following technical solution: a method for controlling the trajectory of a metal droplet, wherein the method comprises the following steps:

[0008] Charging the metal droplets generated by the droplet generator to make the metal droplets charged;

[0009] Detecting the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet;

[0010] Whether the metal droplet is located on a preset running trajectory is determined based on the position signal; if the metal droplet deviates from the preset running trajectory, the deflection electric field and / or magnetic field in which the metal droplet is located is adjusted so that the metal droplet returns to the preset running trajectory under the action of the deflection electric field and / or magnetic field.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0012] As a preferred technical solution, the method for controlling the trajectory of the metal droplet further includes detecting the amount of electricity carried by the charged metal droplet before detecting the trajectory of the charged metal droplet.

[0013] As a preferred technical solution, the method for controlling the trajectory of a metal droplet, wherein the trajectory of the charged metal droplet is detected to obtain a position signal of the metal droplet, specifically comprises:

[0014] A track detection device is arranged on the path of the charged metal droplet, wherein the track detection device comprises a four-quadrant detector;

[0015] The four-quadrant detector is used to detect the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet.

[0016] As a preferred technical solution, the method for regulating the running trajectory of the metal droplet is characterized in that, whether the metal droplet is located on a preset running trajectory is determined based on the position signal; if the metal droplet has not deviated from the running trajectory, the running trajectory of the charged metal droplet is not regulated.

[0017] In a second aspect, a control system for a metal droplet running trajectory is provided, which is used to control the running trajectory of the metal droplet, and includes:

[0018] A droplet generator, used to generate metal droplets;

[0019] A charging electrode, arranged below the droplet generator, for charging the metal droplets; the charging electrode is connected to a power source;

[0020] The trajectory control device is arranged below the charging electrode and is used to detect the position information of the charged metal droplets and to control the metal droplets that deviate from the preset running trajectory; the trajectory control device includes: a deflection device and a trajectory detection device.

[0021] As a preferred technical solution, the control system for the trajectory of metal droplets further comprises a charge detection device for detecting the charge of the charged metal droplets.

[0022] As a preferred technical solution, the metal droplet trajectory control system is described, wherein the trajectory detection device includes a four-quadrant detector and a controller electrically connected to the four-quadrant detector; the deflection device includes a deflection electrode and a signal generator electrically connected to the deflection electrode; and the signal generator is communicatively connected to the controller.

[0023] As a preferred technical solution, in the control system for the trajectory of metal droplets, the charge detection device includes a copper detection electrode and an oscilloscope electrically connected to the copper detection electrode.

[0024] As a preferred technical solution, in the control system for the trajectory of metal droplets, the four-quadrant detector is composed of four independent and completely identical quadrant-shaped photodiodes.

[0025] In the third aspect, an extreme ultraviolet light source system is used for chip preparation and detection, wherein the extreme ultraviolet light source system includes a metal droplet trajectory control system and a laser as described above; the metal droplet trajectory control system controls the deviated metal droplet landing point to the laser focus generated by the laser.

[0026] Beneficial effects: Compared with the prior art, the control method provided by the present invention belongs to closed-loop advance control, and the droplets are precisely controlled according to the droplet position signal in real time. Thus, the droplets can accurately reach the laser focus. Since the droplet mass is very small and the response time is short, the shortcomings of the prior art are effectively solved, and the accuracy and efficiency of droplet control are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the process flow of the method for controlling the trajectory of a metal droplet provided by the present invention;

[0028] Figure 2 A schematic diagram of the structure of the control system for the running trajectory of metal droplets provided by the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the extreme ultraviolet light source system provided by the present invention. DETAILED DESCRIPTION

[0030] The present invention provides a method and system for controlling the trajectory of a metal droplet, and an extreme ultraviolet light source system. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and do not mean a necessary sequence, unless otherwise specified that a certain sequence must be followed. The serial numbers themselves, such as "first", "second", etc., assigned to the components herein are only used to distinguish the objects described and do not have any order or technical meaning.

[0032] like Figure 1 As shown, the present invention provides a method for controlling the trajectory of a metal droplet, comprising the following steps:

[0033] S10, charging the metal droplets generated by the droplet generator to make the metal droplets charged.

[0034] Specifically, the droplet generator can be a droplet generating device based on various technologies such as piezoelectric inkjet printing, jet splitting, droplet collision splitting, etc. The metal can be tin, and the metal droplets are induced to be charged when passing through the charging electrode. Droplet charging refers to the negative charge generated by electrostatic induction when the droplet approaches the electrode plate (positive pole of the power supply), which will be distributed on the surface of the droplet. By charging the metal droplets, it is convenient to subsequently control the operation of the metal droplets, and realize fine control of the trajectory of the metal droplets.

[0035] S20, detecting the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet.

[0036] Specifically, a trajectory detection device including a four-quadrant detector can be used to detect the trajectory of the charged metal droplet moving downward, wherein the four-quadrant detector is composed of four independent but identical quadrant-shaped photodiodes, which are separated by 0.1 mm and combined into a circular detection area to provide two-dimensional incident light position measurement. When light is incident on the sensor, each detector generates a photocurrent. Based on the acquired signals, a suitable A / D converter is used to determine the differential signal, and then the position signal of the metal droplet is obtained. The four-quadrant detector converts the light intensity signal into a digital signal for display, analysis or storage.

[0037] S30. Determine whether the metal droplet is located on a preset running trajectory based on the position signal. If the metal droplet deviates from the preset running trajectory, adjust the deflection electric field and / or magnetic field in which the metal droplet is located so that the metal droplet returns to the preset running trajectory under the action of the deflection electric field and / or magnetic field.

[0038] Specifically, the four-quadrant detector transmits the position signal of the metal droplet to the controller, and the controller determines whether the metal droplet is still located at the center of the four-quadrant detector based on the position signal. If the metal droplet is not at the center of the four-quadrant detector, the controller transmits the feedback signal to the signal generator, and the signal generator applies a deflection signal to the electric field, so that the droplet returns to the center position under the action of the deflection electric field. It should be noted that the electric field is used as an example here to control the metal droplets. Of course, it can also be in the form of a magnetic field, or the electric field and the magnetic field can be used together to control the metal droplets. The preset running trajectory refers to the trajectory of the metal droplet that can fall into a specified position after it is generated, such as falling to the focus of the laser.

[0039] In the present invention, the deflection electric field can be adjusted by feeding back the position signal of the deviated metal droplet to the controller through a four-quadrant detector, and the controller calculates the electric field signal required to return the metal droplet to the preset track based on the position signal, transmits the electric field signal to the signal generator, and then the signal generator controls the deflection electric field to return the metal droplet to the preset track. Similarly, when the electric field is changed to a magnetic field, the controller calculates the magnetic field signal required to return the metal droplet to the preset track based on the position signal, transmits the magnetic field signal to the signal generator, and then the signal generator controls the deflection magnetic field to return the metal droplet to the preset track. Of course, the magnetic field and the electric field can also work together to complete the process. Since the electric field or magnetic field is used to regulate the movement of the metal droplet, the regulation can be faster and more accurate, and does not require the use of complex equipment structures.

[0040] In one implementation of the present invention, after the metal droplets are charged, the amount of charge carried by the metal droplets can also be detected. By detecting the amount of charge carried by the metal droplets, the amount of charge carried can be monitored in real time to avoid the situation where the deflection electric field cannot play an adjustment role due to the small amount of charge carried by the metal droplets after charging.

[0041] In one implementation of the present invention, when it is detected that the motion trajectory of the charged metal droplet has not deviated, there is no need to regulate it.

[0042] Based on the same inventive concept, the present invention also provides a control system for the trajectory of metal droplets, which is used to control the trajectory of metal droplets. Figure 2As shown, it includes: a droplet generator 10, a charging electrode 20, a charge detection device 30 and a trajectory control device 40, wherein the droplet generator 10 is mainly used to generate metal droplets. As an example, the droplet generator can be a droplet generating device based on various technologies such as piezoelectric inkjet printing, jet splitting, droplet collision splitting, etc. The charging electrode 20 is connected to a high-voltage power supply 21, which is used to charge the metal droplets coming out of the droplet generator. It is arranged below the droplet generator, and the two plates form a channel. When the metal droplets pass through the channel, the negative charge generated by the electrostatic induction phenomenon will be distributed on the surface of the droplets. After the droplets are charged, it is necessary to detect the charge of the droplets. A copper core with a smooth cross-section can be used as a detection electrode 31. The copper core has good conductivity. When the droplets approach the detection electrode, an induced charge is generated on the surface of the copper detection electrode. The rear end of the copper core uses an amplifier circuit to regenerate and amplify the detection signal and transmit the detection signal to an oscilloscope 32. According to the waveform displayed by the oscilloscope, the charge of the metal droplets is obtained, and the charge of the metal droplets is monitored in real time.

[0043] The trajectory control device 40 is arranged below the charge monitoring device 30, and is used to detect the position information of the charged metal droplet and control the metal droplet that deviates from the preset running trajectory; the trajectory control device 40 includes: a deflection device and a trajectory detection device. The deflection device includes a deflection electrode 410 and a signal generator 411 connected to the deflection electrode, and the trajectory detection device includes a four-quadrant detector 420 and a controller 421 connected thereto, and the controller 421 is also electrically connected to the signal generator 411. When the droplet enters the deflection electric field and passes through the four-quadrant detector, the four-quadrant detector will generate a position signal and transmit it to the controller, and the controller determines whether the droplet is still located at the center of the four quadrants based on the position signal. If the droplet is not at the center of the four-quadrant system, the controller transmits a feedback signal to the signal generator, and applies a deflection signal to the electric field through the signal generator, so that the droplet returns to the center position under the action of the deflection electric field.

[0044] In one implementation of the present invention, the four-quadrant detector is composed of four independent but identical quadrant-shaped photodiodes, which are separated by 0.1 mm and combined into a circular detection area to provide two-dimensional incident light position measurement.

[0045] Based on the same inventive concept, the present invention also provides an extreme ultraviolet light source system for chip preparation and detection, such as Figure 3 As shown, including: Figure 2The control system of the metal droplet trajectory and the laser 50 shown in the figure; the control system of the metal droplet trajectory controls the deviated metal droplet landing point to the laser focus generated by the laser, forming an extreme ultraviolet light source 60. In the present invention, the droplet itself is controlled in a closed loop, and the droplet is precisely controlled by the deflection electric field in real time according to the droplet position signal. Since the extreme ultraviolet light source system can control the metal droplet before it reaches the laser position, the metal droplet can accurately reach the laser focus, the laser can be precisely focused to bombard the tin droplet, the laser and the tin droplet can fully interact, and the output EUV light is stable.

[0046] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for controlling the trajectory of a metal droplet, characterized in that: The control method comprises the following steps: Charging the metal droplets generated by the droplet generator to make the metal droplets charged; Detecting the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet; Whether the metal droplet is located on a preset running trajectory is determined based on the position signal; if the metal droplet deviates from the preset running trajectory, the deflection electric field and / or magnetic field in which the metal droplet is located is adjusted so that the metal droplet returns to the preset running trajectory under the action of the deflection electric field and / or magnetic field.

2. The method for controlling the trajectory of metal droplets according to claim 1, characterized in that: Before detecting the running trajectory of the charged metal droplet, the method also includes detecting the amount of electricity carried by the charged metal droplet.

3. The method for controlling the trajectory of metal droplets according to claim 1, characterized in that: Detecting the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet specifically includes: A track detection device is arranged on the path of the charged metal droplet, wherein the track detection device comprises a four-quadrant detector; The four-quadrant detector is used to detect the running trajectory of the charged metal droplet to obtain a position signal of the metal droplet.

4. The method for controlling the trajectory of metal droplets according to claim 1, characterized in that: It is determined whether the metal droplet is located on a preset running track according to the position signal. If the metal droplet has not deviated from the running track, the running track of the charged metal droplet is not regulated.

5. A control system for the trajectory of metal droplets, used for controlling the trajectory of metal droplets, characterized in that: include: A droplet generator, used to generate metal droplets; A charging electrode, disposed below the droplet generator, for charging the metal droplets; The charging electrode is connected to a power source; A trajectory control device, disposed below the charging electrode, for detecting the position information of the charged metal droplets and controlling the metal droplets that deviate from a preset running trajectory; The trajectory control device comprises: a deflection device and a trajectory detection device.

6. The metal droplet trajectory control system according to claim 5, characterized in that: The control system also includes a charge detection device for detecting the charge of the charged metal droplets.

7. The metal droplet trajectory control system according to claim 5, characterized in that: The track detection device includes a four-quadrant detector and a controller electrically connected to the four-quadrant detector; the deflection device includes a deflection electrode and a signal generator electrically connected to the deflection electrode; the signal generator is communicatively connected to the controller.

8. The metal droplet trajectory control system according to claim 6, characterized in that: The charge detection device comprises a copper detection electrode and an oscilloscope electrically connected to the copper detection electrode.

9. The metal droplet trajectory control system according to claim 7, characterized in that: The four-quadrant detector is composed of four mutually independent and completely identical quadrant-shaped photodiodes.

10. An extreme ultraviolet light source system for chip preparation and detection, characterized in that: The extreme ultraviolet light source system includes a metal droplet trajectory control system and a laser as described in any one of claims 5-9; the metal droplet trajectory control system controls the deviated metal droplet landing point to the laser focus generated by the laser.

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