Apparatus and method for controlling plasma using liquid metal

Abstract

The present invention relates to an apparatus and a method for controlling plasma using liquid metal, the apparatus comprising: a focus ring forming at least one channel through which liquid metal droplets can be transported together with a transport fluid; a first injection pump connected to the channel to inject the liquid metal droplets; a second injection pump connected to the channel to inject the transport fluid; a memory including at least one instruction; and a processor executing the at least one instruction stored in the memory and controlling the first injection pump and the second injection pump.

Description

Device and method for controlling plasma using liquid metal

[0001] The present invention relates to a device and method for controlling plasma using liquid metal.

[0002] Plasma is an ionized gas created through electron heating. This ionized gas is composed of high-temperature electrons, ions, and neutral species. The energy and density of the ions formed are controlled and used in plasma processes. Depending on the gas used in the plasma, the types of ions formed vary, and these different ions are utilized in various applications, including plasma cleaning, activation, ion implantation, sputtering, and plasma etching.

[0003] In plasma processes, the spatial uniformity of ion energy and density significantly impacts process yield. In particular, in semiconductor processes, spatial uniformity at the wafer edge is significantly degraded due to physical and chemical discontinuities at the edge. This deterioration in uniformity can render 5-7% of the wafer's edge unusable.

[0004] To address these issues, existing plasma control technologies have been developed. First, they are used to ensure physicochemical continuity during the plasma process design phase, and second, they control the plasma spatial uniformity of the process equipment by adding mechanical devices within the process equipment. The first technology cannot actively address spatial unevenness caused by things like focus ring corrosion that occur during the actual plasma process. The second technology has the problem of increasing the unit price and operating cost of the process equipment due to the installation of additional devices within the process equipment.

[0005] Therefore, there is an increasing need for technology development that can lower the unit cost of plasma processes by enabling active control of plasma even during the process and minimizing the installation of additional devices inside the process equipment, thereby eliminating the increase in operating costs that occur during plasma control.

[0006] Embodiments of the present invention for solving these conventional problems provide a device and method for controlling plasma using liquid metal, which enables active control of plasma even during a process by controlling the length and position of liquid metal droplets using microfluidic technology in a space requiring plasma control and modifying the strength and direction of electric and magnetic fields caused by the liquid metal.

[0007] In order to solve the above technical problem, a plasma control device according to an embodiment of the present invention includes: a focus ring forming at least one channel through which a liquid metal droplet can be transported together with a transport fluid; a first injection pump connected to the channel and injecting the liquid metal droplet; a second injection pump connected to the channel and injecting the transport fluid; a memory including at least one instruction; and a processor executing the at least one instruction stored in the memory and controlling the first injection pump and the second injection pump; wherein the processor can control the flow rate characteristics of the liquid metal droplet and the transport fluid by alternately controlling the first injection pump and the second injection pump.

[0008] In one embodiment of the present invention, the processor can determine the flow rate ratio of the liquid metal and the transport fluid based on length information of the liquid metal droplet recorded in advance in memory.

[0009] In one embodiment of the present invention, the processor can set a range of capillary numbers so that the liquid metal is formed into droplets when injected into the channel.

[0010] In one embodiment of the present invention, the processor determines a flow rate ratio of the liquid metal and the transport fluid based on length information of the liquid metal droplets recorded in advance in memory, and determines a flow rate of the transport fluid corresponding to the determined flow rate ratio and distance information between the liquid metal droplets recorded in advance in memory, wherein the flow rate of the transport fluid can be determined within a flow rate range that satisfies the capillary number range.

[0011] In one embodiment of the present invention, the processor can determine the flow rate of the liquid metal using the flow rate ratio and the flow rate of the transport fluid.

[0012] In one embodiment of the present invention, the focus ring further comprises at least one electrode connected to at least one point of the focus ring and electrically connected to the liquid metal droplet when the liquid metal droplet passes the point; and a power electrode that applies a voltage to the electrode; wherein the processor can control the power electrode to apply a voltage to the electrode.

[0013] In one embodiment of the present invention, a camera unit for obtaining image data on plasma changes; and a display unit; are further included, wherein the processor can receive image data on plasma changes when the liquid metal droplet passes through at least one electrode provided in the channel and display the image data on the display unit.

[0014] In one embodiment of the present invention, the focus ring forms two channels having different positional relationships with the wafer, and each channel is connected to at least one electrode that is electrically connected to the liquid metal when the liquid metal droplet passes the point, and the processor can control plasma characteristics around the wafer by selectively applying voltage to the electrodes formed in the different channels.

[0015] In one embodiment of the present invention, the channel may be implemented as an integral part of the focus ring within the focus ring or may be inserted into the focus ring.

[0016] In order to solve the above technical problem, a plasma control method according to an embodiment of the present invention is a method for controlling plasma using a focus ring that forms a channel through which liquid metal droplets are transported together with a transport fluid, the method comprising: a step of receiving information on the length of the liquid metal droplets and the distance between the liquid metal droplets; a step of determining a flow rate ratio of the liquid metal and the transport fluid using the length of the liquid metal droplets; a step of determining a flow rate of the transport fluid corresponding to the determined flow rate ratio and the distance information between the liquid metal droplets; a step of determining a flow rate of the liquid metal using the flow rate ratio and the flow rate of the transport fluid; and a step of alternately injecting the transport fluid and the liquid metal droplets into the channel according to the determined flow rates; wherein the flow rate can be determined within a range that satisfies a preset Capillary number range.

[0017] As described above, the device and method for controlling plasma using liquid metal according to the present invention can control the length and position of liquid metal droplets using microfluidic technology in a space where plasma control is required, and can modify the intensity and direction of electric and magnetic fields caused by the liquid metal, thereby enabling local control of electric fields and real-time control of plasma using the fluidity of the liquid metal, and can minimize the installation of additional devices inside the equipment, thereby enabling miniaturization and simplification of the equipment.

[0018] FIG. 1 is a schematic diagram illustrating a system for plasma control according to an embodiment of the present invention.

[0019] FIG. 2 is a plan view schematically showing a plasma equipment according to an embodiment of the present invention.

[0020] FIG. 3 is a drawing schematically showing the main configuration of an electronic device for plasma control according to an embodiment of the present invention.

[0021] Figure 4 is a flowchart for explaining a plasma control method according to an embodiment of the present invention.

[0022] Figure 5 is experimental data showing the length of liquid metal droplets and the generation cycle of liquid metal droplets according to the flow rate ratio according to an embodiment of the present invention.

[0023] FIG. 6 is a plan view showing a plasma reaction according to the transport of liquid metal droplets according to an embodiment of the present invention.

[0024] FIG. 7 is a front view schematically showing a form in which liquid metal droplets and a transport fluid are transported in a channel according to a flow rate ratio according to an embodiment of the present invention.

[0025] FIG. 8 is a plan view showing a plasma reaction according to the transport of liquid metal droplets in a channel having a plurality of electrodes according to another embodiment of the present invention.

[0026] FIG. 9 is a cross-sectional view showing a plasma reaction according to the transport of liquid metal droplets in a plurality of channels according to another embodiment of the present invention.

[0027] Fig. 10 is a cross-sectional view showing a plasma reaction depending on whether liquid metal droplets are transported according to an embodiment of the present invention.

[0028] The national research and development projects that supported this invention are as follows.

[0029] [Project Number] N10240101

[0030] [Ministry Name] Ministry of Science and ICT

[0031] [Name of Project Management (Specialist) Institution] Korea Advanced Institute of Science and Technology

[0032] [Research Project Name] KAIST Basic Project 1 (Government)

[0033] [Research Project Title] Plasma Active Control Using Liquid Metal Composites for Next-Generation Packaging Technology Applications KAIST Key Convergence Research Institute (2024)

[0034] [Name of the project performing organization] Korea Advanced Institute of Science and Technology

[0035] [Research Period] May 1, 2024 - December 31, 2024

[0036]

[0037] [Project Number] N01241158 (RS-2024-00407018)

[0038] [Ministry Name] Ministry of Science and ICT

[0039] [Name of Project Management (Specialist) Institution] National Research Foundation of Korea

[0040] [Research Project Name] Basic Research Laboratory Support Project

[0041] [Research Project Title] Development of a Programmable Electromagnetic Liquid Metal Composite System for Active Plasma Control

[0042] [Name of the project performing organization] Korea Advanced Institute of Science and Technology

[0043] Research Period: August 1, 2024 - July 31, 2025

[0044]

[0045] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. In the drawings, portions irrelevant to the description may be omitted for clarity in describing the present invention, and the same reference numerals may be used throughout the specification for identical or similar components.

[0046] FIG. 1 is a schematic diagram illustrating a system for plasma control according to an embodiment of the present invention.

[0047] Referring to FIG. 1, a system (100) according to the present invention may include plasma equipment (200) and an electronic device (300).

[0048] The plasma equipment (200) may be a CCP (conductively coupled plasma) type equipment. At this time, the plasma equipment (200) will be described in more detail using the following FIG. 2. FIG. 2 is a plan view schematically illustrating a plasma equipment according to an embodiment of the present invention.

[0049] Referring to FIG. 2, the chamber (230) of the plasma equipment (200) may include a power electrode (210), a focus ring (220) located on the upper portion of the power electrode (210), and at least one electrode (221) provided on the focus ring (220).

[0050] The power electrode (210) is configured to apply voltage to the electrode (221) under control of the processor (360).

[0051] The focus ring (220) may be implemented with a channel through which liquid metal droplets (222) and transport fluid (223) are transported. At this time, the channel may be formed inside the focus ring (220) and implemented as an integral part with the focus ring (220), or may be implemented in a form inserted into the focus ring (220). An injection pipe (224a) may be formed in a part of the focus ring (220) to inject the liquid metal and transport fluid (223) in the direction of the arrow so that the liquid metal droplets (222) may be transported in the direction of the arrow, and a discharge pipe (224b) may be formed so that the liquid metal and transport fluid transported in the channel may be discharged to the outside of the channel. At this time, in the embodiment of the present invention, for the convenience of explanation, it is described as an example that the liquid metal and the transport fluid are transported to the channel through the same injection pipe (224a), but this is not necessarily the case, and the liquid metal and the transport fluid may be transported to the channel through separate injection pipes.

[0052] In addition, a first injection pump and a second injection pump may be connected, respectively, to inject liquid metal droplets (222) and transport fluid (223) into the channel of the focus ring (220) through the injection tube (224a). The first injection pump and the second injection pump may each be controlled by the processor (360).

[0053] In general, the ionization process of gas through electron heating is essential to form plasma, and the ionization process is greatly affected by the electric field. Therefore, in the present invention, metal nanoparticles are included to control the shape, intensity, and density of the local electric field, and thus, the electrical properties are good and the electrical conductivity is 10. 6 It is ideal to use a gallium-based liquid metal with a S / m or higher.

[0054] In addition, in order to increase the plasma control effect using liquid metal, a background is required for electrons to cluster on the surface of the liquid metal. For this purpose, the transport fluid (223) for transporting the liquid metal in the form of droplets must have electrical characteristics that are comparable to those of the liquid metal. In particular, it is difficult to form liquid metal droplets of a uniform volume with liquid metal that forms an oxide film with a thickness of 1 nm at a high oxygen concentration in an environment. The transport fluid (223) for stably transporting the liquid metal droplets uses the HSP (Hansen solubility parameters) of the corresponding fluid to determine the oxygen solubility of the fluid. ) can be estimated, and based on the estimated oxygen saturation, oxygen solubility ( ) can be used as a transport fluid (223) by calculating the oxygen solubility value satisfying -3.5. Representative examples of such transport fluids (223) include polyethylene glycol, propylene glycol, glycerol, and ethylene glycol.

[0055] More specifically, the fluid is , , There are three parameters (measured by people) such as , which are correlated with dispersion, dipole interaction and hydrogen bonding factors respectively. In addition, HSP space is a three-dimensional space where each parameter is represented by a point. , , corresponds to the x, y, z coordinates, and the radius of the sphere ( ) represents the difference in HSP properties of three parameters between the two solvents, and the force factor ( of each solvent in the 3D-HSP diagram) , , ) and oxygen molecules ( , , ) can be calculated using the following mathematical formula 1, and the oxygen solubility of the fluid can be calculated using the following mathematical formula 2.

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] Among these, polyethylene glycol is particularly suitable for plasma use due to its non-conductive, non-polar, and low dielectric constant characteristics. Therefore, the present invention will be described using polyethylene glycol as an example. By using such a transport fluid (223), the formation of an oxide film on the liquid metal droplets can be suppressed, thereby enabling the formation and transport of a uniform volume of liquid metal droplets (222).

[0062] By applying a DC bias electric field using an electrode line to the plasma diffusion path of an atmospheric pressure plasma jet, it is possible to control the velocity of ions and the type and density of radicals formed. To this end, at least one electrode (221) may be formed in a channel through which a liquid metal droplet (222) and a transport fluid (223) are transported. At this time, FIG. 2 will be described as an example in which one electrode (221) is formed. When a liquid metal droplet (222) transported in the channel contacts an electrode (221) connected to an external electric field power source and current flows, an external electric field is applied to the liquid metal droplet (222), and the electric field distribution around the liquid metal droplet (222) changes. At this time, plasma ionization around the liquid metal droplet (222) is increased through the changed electric field distribution, and the energy level of the plasma operating gas due to the electric field is increased, thereby further increasing gas ionization. Therefore, the plasma density around the liquid metal droplet (222) increases.

[0063] In addition, the focus ring (220) may be implemented with a glass material, a ceramic material, a silicon material, etc. The focus ring (220) may be implemented as an integral body as in the embodiment of the present invention, or may be implemented as a module and implemented by assembling a plurality of modules.

[0064]

[0065] FIG. 3 is a drawing schematically showing the main configuration of an electronic device for plasma control according to an embodiment of the present invention.

[0066] Referring to FIG. 3, an electronic device (300) according to the present invention may include a communication unit (310), an input unit (320), a camera unit (330), a display unit (340), a memory (350), and a processor (360).

[0067] The communication unit (310) transmits a control signal to the plasma equipment (200) through communication with the plasma equipment (200). To this end, the communication unit (310) transmits a control signal to the plasma equipment (200) via 5G (5 thIt can perform wireless communications such as LTE-A (long term evolution-advanced), LTE, and Wi-Fi (wireless fidelity), as well as wired communications such as cable communications.

[0068] The input unit (320) generates input data in response to user input of the electronic device (300). To this end, the input unit (320) may include input devices such as a keyboard, mouse, keypad, dome switch, touch panel, touch key, and button.

[0069] The camera unit (330) may include a plurality of cameras. The camera unit (330) may be installed around the electrode (221) implemented inside the focus ring (220) of the plasma equipment (200) to obtain image data on plasma changes caused by liquid metal droplets (222) passing around the electrode (221). In addition, in the embodiment of the present invention, for the convenience of explanation, it is exemplified that the camera unit (330) directly provides image data to the processor (360), but the present invention is not necessarily limited thereto. That is, the camera unit (330) may be installed in a state separated from the electronic device (300) and transmit image data to the processor (360) through communication with the communication unit (310). To this end, the camera unit (330) may perform communication with the communication unit (310) such as Wi-Fi (wireless-fidelity), BLE (Bluetooth low energy), etc.

[0070] The display unit (340) outputs output data according to the operation of the electronic device (300). To this end, the display unit (340) may include a display device such as a liquid crystal display (LCD), a light emitting diode (LED) display, or an organic light emitting diode (OLED) display. In addition, the display unit (340) may be implemented in the form of a touch screen by being combined with the input unit (320).

[0071] The memory (350) can store various programs for operating the electronic device (300). In particular, the memory (350) can store a capillary number set to generate liquid metal droplets in the processor (360) and a flow rate ratio of the liquid metal droplets (222) and the transport fluid (223). In addition, the memory (350) can store a flow rate set to alternately input the liquid metal droplets (222) and the transport fluid (223) from the pump into the channel according to the flow rate ratio of the liquid metal droplets (222) and the transport fluid (223) set in the processor (360).

[0072] The processor (360) sets a dimensionless number, the capillary number (Ca), as a control parameter for generating liquid metal droplets according to the input of the input unit (320). At this time, the capillary number can be calculated using the flow rate of the transport fluid (223), the viscosity of the transport fluid (223), the surface energy between the liquid metal and the transport fluid, and the cross-sectional area of ​​the channel.

[0073] The processor (360) sets the flow rate ratio of the liquid metal droplets (222) and the transport fluid (223) for moving the liquid metal droplets (222) in the channel according to the input of the input unit (320). For example, the processor (360) can set the flow rate of the transport fluid (223) within a range of 1 to 5 ml / min, and the flow rate ratio can be set to 0.01 to 2.5. The spacing between the liquid metal droplets (222) and the length of the liquid metal droplets can be determined by the flow rate ratio and the flow rate of the transport fluid (223).

[0074] The processor (360) can set a range of capillary numbers within an appropriate range. Through this, when uniformly formed liquid metal droplets (222) and transport fluid (223) are transported in a channel implemented within a focus ring (220), the phenomenon of the wall surface of the channel being wetted by the liquid metal droplets (222) can be prevented.

[0075] The processor (360) sets the flow rate at which liquid metal droplets (222) and transport fluid (223) can be injected into the channel based on the set flow rate ratio.

[0076] When a control start signal for controlling plasma is received from the input unit (320), the processor (360) can control the plasma equipment (200) so that liquid metal droplets (222) and transport fluid (223) can be alternately injected into the channel according to the set flow rate. This can be represented as in Fig. 2. When the liquid metal droplets (222) are transported into the channel of the focus ring (220) through the injection tube (224a), the transport fluid (223) is alternately transported into the channel of the focus ring (220) through the injection tube (224a).

[0077] The processor (360) controls the camera unit (330) to obtain image data on plasma that changes when a liquid metal droplet (222) touches the electrode (221), and displays the obtained image data on the display unit (340).

[0078]

[0079] Figure 4 is a flowchart for explaining a plasma control method according to an embodiment of the present invention.

[0080] Referring to FIG. 4, in step 401, the processor (360) sets liquid metal droplet information according to the input of the input unit (320). At this time, the liquid metal droplet information may include the interval between liquid metal droplets transported in the channel implemented inside the focus ring (220) and the length of the liquid metal droplets.

[0081] Liquid metal droplet information may be stored in advance in memory (350).

[0082] In addition, characteristic information according to the type of transport fluid (223) may be stored in memory (350) in advance or may be stored in memory (350) according to input information generated by the input unit (320). The characteristic information of transport fluid (223) may include viscosity (μ) and slope (α) information according to the flow rate ratio.

[0083] In step 403, the processor (360) can determine the flow rate ratio of the transport fluid and the liquid metal.

[0084] As will be described later, the length of the liquid metal droplet (222) and the period in which the liquid metal droplet (222) flows into the channel can be adjusted by controlling the flow rate ratio. For example, the processor (360) can calculate the flow rate ratio corresponding to the liquid metal droplet length set in step 401 using [Mathematical Formula 4] described later and determine the calculation result as the flow rate ratio.

[0085] In step 405, the processor (360) determines the applicable range of the capillary number (Ca). The capillary number is a dimensionless number for setting an appropriate range in which the liquid metal can maintain the shape of a droplet. The appropriate range in which the liquid metal can maintain the shape of a droplet can be determined experimentally. For example, Ca is 10 -5 10 inland -3In the case of a range, the liquid metal can maintain the form of a droplet. At this time, the capillary number can be calculated using the flow rate of the transport fluid (223), the viscosity of the transport fluid (223), the interfacial energy between the liquid metal and the transport fluid, and the cross-sectional area of ​​the channel, as shown in the following mathematical equation 3.

[0086]

[0087]

[0088]

[0089] At this time, μ(Pa·s) is the viscosity of the transport fluid, μ WF is the velocity of the transport fluid, Q WF (m 3 / s) is the flow rate of the transport fluid, is the interfacial energy between the transport fluid and the liquid metal droplet, and A represents the cross-sectional area of ​​the channel. In addition, the range of Ca required for the formation of liquid metal droplets is 1*10 -5 1*10 in -3 It could be between.

[0090] The scope of application of Ca does not necessarily have to be performed in step 405, but can be performed at any time before determining the flow rate, and may be recorded in advance in the memory (350).

[0091] Once an appropriate Ca range is determined, the processor (360) can set the flow rates of the transport fluid and the liquid metal within the determined Ca range. Through this, when uniformly formed liquid metal droplets (222) and transport fluid (223) are transported in a channel implemented within the focus ring (220), the phenomenon of the wall of the channel being wetted by the liquid metal droplets (222) can be prevented.

[0092] The processor (360) can determine the flow rate of the transport fluid (223) in response to the distance between the liquid metal droplets (222). As described below, the control variables that determine the distance between the liquid metal droplets (222) may be the flow rate ratio and the flow rate of the transport fluid (223). For example, since the flow rate ratio has already been determined in step 403, the processor (360) can calculate the flow rate of the transport fluid (223) in response to the desired distance between the liquid metal droplets (222) and determine the calculation result as the flow rate of the transport fluid (223).

[0093] Meanwhile, when the flow rate of the transport fluid (223) is outside the appropriate Ca range, the processor (360) can notify the user of the device by transmitting information to the user terminal (not shown) or displaying it on the display unit (340) that the flow rate of the transport fluid (223) is outside the appropriate range.

[0094] Once the flow rate of the transport fluid (223) is determined, the flow rate of the liquid metal can also be calculated based on a predetermined flow rate ratio. The processor (360) determines the flow rate of the liquid metal using the determined flow rate ratio and the flow rate of the transport fluid (223).

[0095] In step 407, if a control start signal for controlling plasma is received from the input unit (320), the processor (360) performs step 409, and if the control start signal is not received, the processor returns to step 401 and can re-perform steps 401 to 405.

[0096] In step 409, the processor (360) controls the plasma equipment (200) to inject liquid metal droplets (222) and transport fluid (223) into the channel. At this time, the plasma equipment (200) can alternately inject the liquid metal droplets (222) and transport fluid (223) based on the flow rate set according to the control of the processor (360). The length of the liquid metal droplets (222) and the generation cycle of the liquid metal droplets (222) according to the flow rate ratio of the liquid metal droplets (222) and the transport fluid (223) are as shown in FIG. 5. FIG. 5 is experimental data obtained by testing the length of the liquid metal droplets and the generation cycle of the liquid metal droplets according to the flow rate ratio according to an embodiment of the present invention.

[0097] Fig. 5a shows a graph for confirming the relationship between the length of the liquid metal droplet (222) and the flow rate ratio. More specifically, referring to Fig. 5a, in order to obtain a universal relationship between different fluids, i.e., ethylene glycol, propylene glycol, glycerol, and polyethylene glycol with different average molecular weights, the length of the liquid metal droplet was dimensionless as l / 2r, where l represents the axial length of the droplet and r represents the radius of the channel. The flow rate ratio ( )at is the flow rate of liquid metal ml / min, refers to the flow rate ml / min of the transport fluid. As shown in Fig. 5A, it can be confirmed that the slope α when the flow rate ratio is 0.1 or higher is 0.35.

[0098] Figure 5b shows the generation cycle of continuously generated liquid metal droplets (222). ) and the flow rate ratio. More specifically, referring to Fig. 5b, the droplet generation time is used to obtain a universal relationship between different fluids, similar to Fig. 5a. It was nondimensionalized, and it can be confirmed that it has a slope α when the flow ratio is 0.1 or higher. If the flow ratio is less than 0.1, the effect of the flow ratio may become minimal.

[0099] Variables l / 2r related to the formation of liquid metal droplets (222) can be expressed using the following mathematical expressions 4 and 5.

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] Based on this, it can be seen that the liquid metal droplet length and the generation cycle of the liquid metal droplet are almost the same at the same flow rate ratio regardless of the flow rate of the transport fluid (223).

[0106] In addition, the distance D between liquid metal droplets (222) can be calculated through the droplet generation cycle and is as follows [Mathematical Formula 6].

[0107]

[0108]

[0109]

[0110] Referring to [Mathematical Formula 6], it can be seen that the distance D between liquid metal droplets (222) is calculated by the flow rate ratio and the flow rate of the transport fluid, and when the flow rate ratio is determined, it can be controlled by the flow rate of the transport fluid.

[0111] In step 411, the processor (360) controls the camera unit (330) to acquire image data on plasma changing around the liquid metal droplet (222). More specifically, when the liquid metal droplet (222) transported in the channel touches the electrode (221) connected to the external electric field power source, an external electric field is applied to the liquid metal droplet (222), and the electric field distribution around the liquid metal droplet (222) changes. At this time, plasma ionization around the liquid metal droplet (222) increases through the changed distribution of the electric field, and the energy level of the plasma operating gas due to the electric field increases, thereby further increasing gas ionization. Therefore, the plasma density and intensity around the liquid metal droplet (222) increase.

[0112] The processor (360) acquires image data on the phenomenon in which the plasma density and intensity change around the liquid metal droplet (222), and in step 413, the processor (360) displays the acquired image data on the display unit (340).

[0113] In step 415, if the processor (360) receives a control termination signal for terminating plasma control from the input unit (320), the processor (360) terminates the process, and if the control termination signal is not received, the processor returns to step 403 and can re-perform steps 403 to 413. Accordingly, the present invention has the effect of enabling active control of plasma even during the process by resetting the flow rate ratio and flow rate according to the input of the input unit (320) before plasma control is terminated.

[0114]

[0115] Fig. 6 is a plan view illustrating a plasma reaction according to the transport of liquid metal droplets according to an embodiment of the present invention. Fig. 7 is a front view schematically illustrating a form in which liquid metal droplets and transport fluid are transported in a channel according to a flow rate ratio according to an embodiment of the present invention.

[0116] Referring to FIG. 6, as shown in FIG. 6a, a liquid metal droplet (222) is transported to a channel implemented in a focus ring (220) through an injection tube (224a). After the liquid metal droplet (222) is transported to the channel or simultaneously with the liquid metal droplet (222) being transported to the channel, a transport fluid (223) is transported to the channel implemented in the focus ring (220) through the injection tube (224a).

[0117] In this way, the liquid metal droplets (222) and the transport fluid (223) can be transported alternately in the channel with continuity. At this time, the liquid metal droplets (222) and the transport fluid (223) can be transported in the channel according to the flow rate set based on the flow rate ratio set by the input of the input unit (320).

[0118] When a liquid metal droplet (222) being transported in a channel comes into contact with an electrode (221) connected to an external electric field power source as shown in Fig. 6b and current flows, an external electric field is applied to the liquid metal droplet (222) and the electric field distribution changes around the liquid metal droplet (222). As a result, plasma ionization around the liquid metal droplet (222) increases, and the energy level of the plasma operating gas due to the electric field rises, further increasing gas ionization, thereby increasing the density and intensity of the plasma (225) around the liquid metal droplet (222).

[0119] Next, when the liquid metal droplet (222) being transported in the channel moves away from the electrode (221) as shown in Fig. 6c, the plasma (225) returns to the state as shown in Fig. 6A. At this time, as the liquid metal droplet (222) and the transport fluid (223) move, the liquid metal droplet (222) and the transport fluid (223) can be continuously injected into the injection tube (224a) and transported into the channel.

[0120] At this time, FIGS. 7a and 7b show the lengths of the liquid metal droplets (222) and the transport fluid (223) transported in the channel implemented in the focus ring (220) when the flow rate of the transport fluid (223) is the same as 3 ml / min and the flow rate ratios of the liquid metal droplets (222) and the transport fluid (223) are different from each other. For example, FIG. 7a shows a case where the flow rate ratio of the liquid metal droplets (222) and the transport fluid (223) is 0.5, and FIG. 7b shows a case where the flow rate ratio of the liquid metal droplets (222) and the transport fluid (223) is 1.0.

[0121] When the flow rate ratio is 0.5 as in Fig. 7a, since the length of the liquid metal droplet (222) passing through the electrode (221) is shorter than that in Fig. 7b, the density and intensity of the plasma (225) may be generated less than when the flow rate ratio is 1.0 as in Fig. 7b. Conversely, since the flow rate ratio in Fig. 7b is greater than that in Fig. 7a, the length of the liquid metal droplet (222) itself is longer than that in Fig. 7a. Therefore, when the flow rate ratio as in Fig. 7b is present, the density and intensity of the plasma (225) generated when the liquid metal droplet (222) passes through the electrode (221) are greater than when the flow rate ratio is 0.5 as in Fig. 7a.

[0122] In this way, when the liquid metal droplet (222) comes into contact with the electrode (221), the density and intensity of the plasma (225) change around the liquid metal droplet (222), so the plasma can be controlled using the flow rate ratio of the liquid metal droplet (222) and the transport fluid (223).

[0123]

[0124] FIG. 8 is a plan view showing a plasma reaction according to the transport of liquid metal droplets in a channel having a plurality of electrodes according to another embodiment of the present invention.

[0125] Referring to Fig. 8, a plurality of electrodes (221) may be formed at irregular intervals in a channel implemented in a focus ring (220) as in Fig. 8a, and a plurality of electrodes (221) may be formed at regular intervals in the channel as in Fig. 8b. At this time, since the liquid metal droplets (222) and transport fluid (223) transported in the channel are discharged through the discharge pipe (224b), an electrode (221) may not be formed between the injection pipe (224a) and the discharge pipe (224b).

[0126] In addition, the processor (360) can apply an external electric field only to the necessary electrodes among the plurality of electrodes (221) implemented in the channel, so that the plasma density and intensity increase around the liquid metal droplet (222) only when the liquid metal droplet (222) touches the electrode (221) to which the external electric field is applied and current flows. In this way, the present invention can control the density and intensity of the plasma by locally adjusting the intensity of the electric field according to the combination of the position of the electrode (221) and the position of the liquid metal droplet (222) or the form of the electric field applied to the electrode (221). At this time, the form of the electric field may include a direct current, an alternating current, a voltage intensity of the electric field, etc.

[0127]

[0128] FIG. 9 is a cross-sectional view showing a plasma reaction according to the transport of liquid metal droplets in a plurality of channels according to another embodiment of the present invention.

[0129] Referring to FIG. 9, two channels can be implemented in one focus ring (220) as in FIG. 9a. The processor (360) can apply an external electric field only to the electrode (221a) formed in the upper channel among the two channels as in FIG. 9b, so that when the liquid metal droplet (222) comes into contact with the electrode (221a) and current flows, the plasma density and intensity can increase around the corresponding liquid metal droplet (222). In addition, the processor (360) can apply an external electric field only to the electrode (221b) formed in the lower channel among the two channels as in FIG. 9c, so that when the liquid metal droplet (222) comes into contact with the electrode (221b) and current flows, the plasma density and intensity can increase around the corresponding liquid metal droplet (222).

[0130]

[0131] Fig. 10 is a cross-sectional view showing a plasma reaction depending on whether liquid metal droplets are transported according to an embodiment of the present invention.

[0132] Referring to FIG. 10, FIG. 10a is a drawing showing a plasma reaction when a channel is not formed in the focus ring (220) in relation to a conventional technology and liquid metal cannot be used. As shown in FIG. 10a, when performing a wafer process inside a chamber of a plasma device (200), if a separate channel is not implemented in the focus ring (220) and liquid metal cannot be used, the uniformity of the density and intensity of the plasma (225) at the edge of the wafer deteriorates. Therefore, a problem occurs in which 5 to 7% of the edge of the wafer cannot be used.

[0133] FIG. 10b is a drawing showing a plasma reaction when a channel is formed in a focus ring (220) in relation to the present invention and liquid metal is used. As shown in FIG. 10b, when a wafer process is performed inside a chamber of a plasma device (200), a separate channel is implemented in the focus ring (220), and when a liquid metal droplet (222) is transported along the channel, the density and intensity of the plasma (225) increase when the liquid metal droplet (222) approaches the electrode (221). Through this, the uniformity of the plasma (225) can be improved. Therefore, the present invention has the effect of resolving the conventional problem of not being able to use the edge portion of the wafer.

[0134]

[0135] The embodiments of the present invention disclosed in this specification and drawings are merely specific examples intended to facilitate understanding and easily explain the technical content of the present invention, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be interpreted to include all modifications or variations derived based on the technical concept of the present invention, in addition to the embodiments disclosed herein.

Claims

1. A focus ring forming at least one channel through which liquid metal droplets can be transported together with a transport fluid; A first injection pump connected to the above channel for injecting the liquid metal droplet; A second injection pump connected to the above channel for injecting the transport fluid; a memory containing at least one instruction; and A processor that executes at least one command stored in the memory and controls the first injection pump and the second injection pump; The processor alternately controls the first injection pump and the second injection pump to control the flow rate characteristics of the liquid metal droplets and the transport fluid. Plasma control device.

2. In paragraph 1, The above processor, A plasma control device that determines the flow rate ratio of the liquid metal and the transport fluid based on length information of the liquid metal droplets recorded in advance in memory.

3. In paragraph 1, The above processor, A plasma control device that sets a range of capillary numbers so that the liquid metal is formed into droplets when injected into the channel.

4. In paragraph 3, The above processor, Determine the flow rate ratio of the liquid metal and the transport fluid based on the length information of the liquid metal droplet recorded in advance in the memory, Determine the flow rate of the transport fluid corresponding to the determined flow rate ratio and the distance information between liquid metal droplets recorded in advance in the memory, A plasma control device in which the flow rate of the above transport fluid is determined within a flow rate range that satisfies the above capillary number range.

5. In paragraph 4, The above processor, A plasma control device that determines the flow rate of the liquid metal using the above flow rate ratio and the flow rate of the transport fluid.

6. In paragraph 1, At least one electrode connected to at least one point of the focus ring and electrically connected to the liquid metal droplet when the liquid metal droplet passes the point; and Further comprising a power electrode for applying voltage to the above electrode; The above processor, A plasma control device that controls a power electrode and applies voltage to the electrode.

7. In paragraph 6, A camera unit for acquiring image data on plasma changes; and Including further display portions; The above processor, A plasma control device characterized in that it receives image data on plasma that changes when the liquid metal droplet passes through at least one electrode provided in the channel and displays the data on the display unit.

8. In paragraph 1, The above focus ring forms two channels having different positional relationships with the wafer, Each channel is connected to at least one electrode that is electrically connected to the liquid metal droplet as it passes through the point, and The above processor, A plasma control device that controls plasma characteristics around the wafer by selectively applying voltage to electrodes formed in the different channels.

9. In paragraph 1, The above channel is, A plasma control device characterized in that it is implemented as an integral part of the focus ring or inserted into the focus ring.

10. A method for controlling plasma using a focus ring that forms a channel through which liquid metal droplets are transported together with a transport fluid, A step of receiving information on the length of the liquid metal droplet and the distance between the liquid metal droplets; A step of determining the flow rate ratio of the liquid metal and the transport fluid using the length of the liquid metal droplet; A step of determining the flow rate of the transport fluid corresponding to the determined flow rate ratio and distance information between the liquid metal droplets; A step of determining the flow rate of the liquid metal using the flow rate ratio and the flow rate of the transport fluid; and A step of alternately injecting the transport fluid and the liquid metal droplets into the channel according to the determined flow rate; including; A plasma control method in which the above flow rate is determined within a range that satisfies a preset Capillary number range.

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