Patent Application
20240209495
This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2020-0095940, filed on Jul. 31, 2020, in the Korean Intellectual Property Office, and U.S. patent application Ser. No. 17/195,900, filed on Mar. 9, 2021, the disclosure of which is incorporated by reference herein.
The present inventive concept relates to a deposition system and a processing system.
A typical method of forming a thin film on a substrate includes Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD). In a CVD and ALD processes, various reactants can be used to form a thin film on a surface of the substrate. In the process, liquid reactants are generally phase-changed to a gaseous state and supplied to a reaction chamber. After a deposition process is completed, exhaust materials of the process are discharged at an exhaust stage. However, when a vaporizer is used to increase the supply of liquid reactants, the replacement cycle of a canister supplying the liquid reactants may be shortened, and the replacement cycle of a pump may be shortened due to the increase of exhaust materials of the process. In addition, the facility operating the deposition system must be stopped when replacing the canister and the pump.
An aspect of the present inventive concept provides for a deposition system that facilitates maintenance and management of deposition facilities from a viewpoint of mass production.
According to an aspect of the present inventive concept, a deposition system includes: a reaction chamber; a first gas supply unit configured to supply a liquid first precursor stored in a first main tank to the reaction chamber in a gaseous state; a reactant supply unit configured to supply a reactant, reacting with the first precursor, to the reaction chamber; and an exhaust unit configured to discharge an exhaust material generated from the reaction chamber, wherein the first gas supply unit includes a first sub tank, a first liquid mass flow controller, and a first vaporizer, the first precursor filled in the first sub tank by a first automatic refill system is supplied to the reaction chamber by passing through the first sub tank, the first liquid mass flow controller, and the first vaporizer, the first automatic refill system operates to periodically fill the first sub tank with the first precursor in a liquid state stored in the first main tank, and the exhaust unit comprises a plasma pretreatment system chamber to which a plasma pretreatment system for increasing decomposition rate of the exhaust material is applied, a pump, and a scrubber.
According to an aspect of the present inventive concept, a deposition system includes: a reaction chamber; one or more gas supply units configured to supply at least one precursor to the reaction chamber in a gaseous state; a reactant supply unit configured to supply a reactant, reacting with the precursor to the reaction chamber; and an exhaust unit configured to discharge an exhaust material generated from the reaction chamber, wherein the one or more gas supply units include: a sub tank in which the precursor is stored; a vaporizer for supplying the precursor to the reaction chamber in a gaseous state; and a liquid mass flow controller controlling an amount of the precursor supplied to the vaporizer, the exhaust unit includes a plasma pretreatment system chamber, a pump, and a scrubber, and the plasma pretreatment system chamber exhausts the exhaust material through the pump, after a chemical structure of the exhaust material is changed using the plasma pretreatment system.
According to an aspect of the present inventive concept, a process system includes: at least one automatic refill system configured to fill a sub tank automatically with a process material in a liquid state; a gas supply system configured to supply the process material stored in the sub tank to the reaction chamber in a gaseous state; and a plasma pretreatment system configured to induce plasma discharge to change a chemical structure of an exhaust material discharged from the reaction chamber, wherein the gas supply system is configured to operate a liquid mass flow controller and a vaporizer connected between the sub tank and the reaction chamber, and the liquid mass flow controller is configured to control the amount of the process material supplied to the vaporizer.
The above and other aspects, features, and advantages of the present inventive concept will be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:
. 7 is a schematic flowchart illustrating an operation of a plasma pretreatment system in a deposition system according to an example embodiment of the present inventive concept; and
Hereinafter, example embodiments of the present inventive concept will be described in detail with reference to the accompanying drawings as follows.
Referring to
A deposition system 1 according to an example embodiment of the present inventive concept may be a system in which a chemical vapor deposition (CVD) process and/or an atomic layer deposition (ALD) process is performed. The CVD process and the ALD process may be a part of a process for depositing a thin film on a substrate by supplying and reacting a precursor and a reactant into the reaction chamber 10.
A precursor may exist in a liquid or solid state at room temperature, and may be vaporized by a component included in the gas supply unit 20 and supplied to the reaction chamber 10 in a gaseous state. However, this is an example and the present disclosure is not necessarily limited thereto, and the precursor may exist in a gaseous state at room temperature.
In the deposition system 1, the precursor may be a liquid reactant. For example, the precursor may be a metal organic precursor, and may be composed of a group 3, 4, or 5 element. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the precursor may be composed of other elements.
In a general deposition process, it may be necessary to phase change the liquid precursor into a gaseous state using a vaporizer. For example, a bubbler and/or a vaporizer may be used as a vaporization device for phase-changing a precursor into a gaseous state. For example, a precursor may be phase-changed into a gaseous state using a baking process, and a gaseous precursor may be supplied to the reaction chamber 10 using a carrier gas. Meanwhile, a liquid precursor may be vaporized by bubbling the precursor with a carrier gas, and the gas precursor may be supplied to the reaction chamber 10.
The above-described vaporization devices used in the deposition process may vary, depending on a vapor pressure of the liquid precursor. For example, in the case of a precursor having a low vapor pressure, it may be difficult to vaporize a liquid precursor using a bubbler, and a vaporizer may be required. In the case of a precursor having high vapor pressure, the precursor may be vaporized by a baking process.
When the liquid precursor is phase-changed into a gaseous state using a vaporizer, a larger amount of the precursor may be supplied to the reaction chamber 10 than when a bubbler is used. The amount of the precursor supplied to the reaction chamber 10 may be controlled by a liquid mass flow controller (LMFC).
The precursor supplied to the reaction chamber 10 may be stored in a canister. In some cases, if the precursor is less than a predetermined amount in the canister as the process proceeds, the canister may need to be replaced to proceed with the process again. Accordingly, it may be necessary to stop a process facility to replace the canister. For example, it may be necessary to shut down the process facility to remove impurities from inside a pipe connected to the canister, or to replace the canister.
While the deposition process is in progress and/or after the deposition process is completed, exhaust materials may be discharged to an exhaust end of the reaction chamber 10. As an example, the exhaust materials may include gaseous reactants that did not react during the deposition process or by-products of the reaction. Exhaust materials may be changed into a solid phase and accumulated in a pump 32 connected to the exhaust end of the reaction chamber 10, which may compromise the pump. Accordingly, in order to replace the spent pump, it may be necessary to stop the process facility.
In the deposition system 1 according to an example embodiment of the present inventive concept, the reaction chamber 10 may include a deposition chamber in which a deposition process is performed. For example, the deposition process may be a chemical vapor deposition (CVD) and/or an atomic layer deposition (ALD) process. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the reaction chamber 10 of the deposition system 1 according to an example embodiment of the present inventive concept may include a chamber in which another process using gas injection is performed. For example, the reaction chamber 10 may include a polishing process chamber in which cleaning is performed by spraying a cleaning gas after a chemical mechanical polishing (CMP) process, an etching process chamber removing at least a portion of a region of a wafer and/or element layers formed on the wafer by using plasma including radicals and ions of a source gas, or the like. When a process other than the deposition process is performed, the gas supplied to the reaction chamber 10 might not be limited to a precursor.
In the deposition system 1 according to an example embodiment of the present inventive concept, a liquid precursor supplied to the reaction chamber 10 may be stored in a main tank 40. The liquid precursor stored in the main tank 40 may be filled in the gas supply unit 20 by an automatic refill system (ARS). For example, the automatic refill system (ARS) may continuously operate across processes. For example, when the automatic refill system ARS is operated, a negative pressure may be formed in a pipe between the main tank 40 and the gas supply unit 20 by a vacuum pump connected to the pipe. An appropriate amount of a liquid precursor may be filled in the gas supply unit 20 by the formed negative pressure. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and an operation timing and a method of the automatic refill system ARS may differ according to example embodiments.
In the deposition system 1, the gas supply unit 20 may include a sub tank 22, a liquid mass flow controller 23, and a vaporizer 24. As an example, the gas supply unit 20 may further include a filter 25 for filtering out liquid precursors that have not been completely vaporized in the vaporizer 24. In addition, a plurality of valves for controlling a supply of the precursor may be disposed between and/or within the components of the gas supply unit 20. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the number and position of the valves may be determined as necessary.
The sub tank 22 may be filled from the main tank 40 to store a liquid precursor to be used in a corresponding process. As an example, the sub tank 22 may be a canister. The liquid mass flow controller 23 may supply the liquid precursor stored in the sub tank 22 to the vaporizer 24 in a constant amount per unit time. For example, the constant amount per unit time may correspond to a range of about 1 g to 10 g per minute. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the amount of supplied liquid precursor may differ depending on the type of liquid precursor, the amount required to proceed with the process, and the number of substrates on which deposition occurs in one process.
The vaporizer 24 may phase-change the liquid precursor into a gaseous state in order to supply the precursor to the reaction chamber 10. The operation of the vaporizer 24 is not limited to one method, and the liquid precursor may be vaporized by operating in various methods according to example embodiments. The gaseous precursor may be supplied to the reaction chamber 10 through the filter 25.
The configuration of the gas supply unit 20 illustrated in
The reactant supply unit 50 included in the deposition system 1 according to an example embodiment of the present inventive concept may supply a reactant for forming a thin film by reacting with a precursor to the reaction chamber 10. As an example, the supplied reactant may include at least one of H2O, H2O2, O3, NH3, and the like. However, this is an example and is not limited thereto, and the reactants supplied according to the example embodiments may be different.
In the deposition system 1 according to an example embodiment of the present inventive concept, during the deposition process and/or after the deposition process is completed, exhaust materials may be discharged to an exhaust end of the reaction chamber 10. The discharged exhaust materials may be discharged from the deposition system 1 through the exhaust unit 30. The exhaust unit 30 may include a plasma pretreatment system (PPS) chamber 31, a pump 32, and a scrubber 33.
Exhaust materials from the deposition process may be discharged through the pump 32 and the scrubber 33 after passing through a plasma pretreatment system (PPS) in the PPS chamber 31. However, the disposition of the PPS chamber 31 is not limited what is illustrated in
Meanwhile, a plurality of processing chambers may be installed so that the plasma pretreatment system PPS may be repeatedly applied several times.
A plasma pretreatment system (PPS) applied to the exhaust material in the PPS chamber 31 may supply a reactive gas to the exhaust material. As an example, the reactive gas may be O2. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and other reactive gases may be supplied according to example embodiments. Metallic by-products contained in the exhaust material and reactive gases may react to generate products such as zirconia (ZrO2). For example, zirconia may be in powder form. However, products such as zirconia, or the like, may be stacked on an inner wall of the pipe and obstruct the discharge of exhaust material.
In the deposition system 1 according to an example embodiment of the present inventive concept, the plasma pretreatment system PPS may induce plasma discharge in the
PPS chamber 31. Meanwhile, the exhaust material of the deposition process by plasma discharge may be replaced with a material having increased decomposition performance and/or an increased flowability and safety. Accordingly, the plasma pretreatment system PPS can extend a lifespan of the pump 32 and increase an efficiency of the scrubber 33.
For example, when the plasma pretreatment system (PPS) is applied, the lifespan of the pump may be 2 to 3 times that of the pump without the plasma pretreatment system. For example, when the plasma pretreatment system (PPS) is not applied, a replacement cycle of the pump may be 1 month, and when the plasma pretreatment system (PPS) is applied, a replacement cycle of the pump may be 2 months to 3 months. However, this is an example and the present disclosure is not necessarily limited thereto, and the replacement cycle of the pump may differ depending on the process environment, the performance of the plasma pretreatment system (PPS), the performance of the pump, and the like.
In the deposition system 1 according to an example embodiment of the present inventive concept, the exhaust material discharged to the exhaust end of the reaction chamber 10 ay contain materials in various states. The pump 32 may discharge exhaust material using negative pressure. The scrubber 33 ay serve to dissolve and absorb the exhaust materials in a gaseous state. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and various methods for safely discharging and discharging the exhaust material may be applied to the exhaust unit 30, and additional components necessary for this may be further included.
Referring to
The deposition system according to an example embodiment of the present inventive concept may be applied regardless of reaction chamber type. For example, in the past, the batch type reaction chamber was mainly used to increase process speed, but in recent years, single type reaction chambers are increasing in use to increase process accuracy, and accordingly maintenance and management of facilities are becoming more important. The deposition system according to an example embodiment of the present inventive concept makes it easier to maintain and manage the facility, and can increase process efficiency.
Referring to
Referring to
For example, the number of wafers Wb able to be simultaneously processed in the semi-batch type reaction chamber 10b may be less than the number of wafers Wa able to be simultaneously processed in the batch type reaction chamber 10a shown in
Referring to
Referring to
For example, the sub tank 122 may be filled with a liquid precursor LP to a predetermined height H. The bubbler B may inject carrier gas G at a first height h1. For example, the first height h1 may be lower than a predetermined height H filled with the liquid precursor LP. Accordingly, the carrier gas G may be directly injected into the liquid precursor LP. For example, the carrier gas G may be a gas such as N2 having low reactivity. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and various carrier gases G may be used according to example embodiments.
Meanwhile, a bubbling may occur in the liquid precursor LP by the injection of the carrier gas G, and the liquid precursor LP may be vaporized into a gas precursor GP. The gas precursor GP may be supplied to the reaction chamber through a pipe. For example, an inlet of the pipe through which the gas precursor GP exits may be disposed above a surface of the liquid precursor LP. However, this is an example and the present disclosure is not necessarily limited thereto, and the inlet of the pipe may be disposed close to the surface of the liquid precursor LP, or it may be disposed in various ways through which the gas precursor GP may escape.
The liquid precursor LP in which the bubbling may occur may be a material having a predetermined vapor pressure. For example, in the case of a deposition process using a liquid precursor LP having a vapor pressure of about 1 Torr or more at 100° C., the liquid precursor LP may be vaporized using a bubbler B. However, this is an example and the present disclosure is not necessarily limited thereto, and even in a deposition system using a liquid precursor LP having a high vapor pressure, a vaporizer to be described later may be used instead of the bubbler B to increase the amount of precursor supplied.
Referring to
For example, the sub tank 222 may be filled with a liquid precursor LP to a predetermined height H. In order to supply the liquid precursor LP to the liquid mass flow controller 223, a carrier gas G may be injected at a second height h2 of the sub tank 222. For example, the second height h2 may be higher than a predetermined height H filled with the liquid precursor LP. Accordingly, the carrier gas G may be injected onto the surface of the liquid precursor LP.
A part of the liquid precursor LP may be supplied to the liquid mass flow controller 223 along a first pipe L1 by injection of the carrier gas G. For example, an inlet of the first pipe L1 may be disposed at a third height h3, lower than a predetermined height H filled with the liquid precursor LP. However, this is an example embodiment and the arrangement of the first pipe L1 might not be limited thereto.
The liquid precursor LP may be supplied to the vaporizer 224 along a second pipe L2 at an amount controlled by the liquid mass flow controller 223. The gas precursor GP phase-changed into a gaseous state using the vaporizer 224 may be supplied to the reaction chamber along the third pipe L3. Accordingly, the precursor passing through the first pipe L1 and the second pipe L2 may be a liquid precursor LP, and the precursor passing through the third pipe L3 may be a gas precursor GP.
In the deposition system according to an example embodiment of the present inventive concept, the liquid precursor LP using the vaporizer 224 may be a material having a low vapor pressure. However, this is an example and the present disclosure is not limited thereto, the vaporizer 224 may be used to increase the supply of the gas precursor GP regardless of the precursor's vapor pressure.
Referring to
Referring to
When the liquid precursor filled in the sub tank is less than a predetermined amount, an automatic refill system may be operated to fill the liquid precursor stored in the main tank into the sub tank (S110). For example, a vacuum pump may be disposed between the main tank and the sub tank, and the liquid precursor may be automatically filled using a negative pressure formed by the vacuum pump. When the liquid precursor filled in the sub tank is greater than or equal to a predetermined amount, the above-described deposition process may be performed (S120).
After the deposition process is completed (S130), it is determined whether to continue the deposition process (S140), and if so, the deposition process may be repeated again from the step S100.
In the automatic refill system applied to the deposition system according to an example embodiment of the present inventive concept, instead of continuously replacing the canister, a deposition process may be performed by filling the liquid in a sub tank. Thereby, process efficiency may be increased by utilizing a period of facility shutdown that may otherwise be spent replacing the canister as an operating period.
Referring to
As an example, the exhaust unit 30 may include a PPS chamber 31, a pump 32, and a scrubber 33 that applies a plasma pretreatment system (PPS) for changing the chemical structure of the exhaust material WP.
In the deposition system, the plasma pretreatment system may facilitate discharge by decomposing and/or replacing the exhaust material WP discharged from the reaction chamber. As an example, the plasma pretreatment system may be applied to the exhaust material WP in the PPS chamber 31. However, the plasma pretreatment system is not limited to being applied to the deposition system, and may be applied not only to the deposition process but also to other processes for discharging the exhaust material WP. For example, the plasma pretreatment system may be applied to processes such as ashing, etching, annealing, and cleaning.
The exhaust material WP before the plasma pretreatment system is applied may be a precursor that has not yet reacted and/or a by-product remaining after the reaction. For example, the exhaust material WP may be a material having a relatively complex structure, such as zirconia. Accordingly, when the exhaust material WP is discharged without the application of the plasma pretreatment system, a lifespan of the pump 32 may be shortened due to issues such as excessive force on the pump 32 or accumulation of the exhaust material WP in the pipe.
A plasma pretreatment system may be applied to the PPS chamber 31. The plasma pretreatment system may include supplying a reactive gas (RG) and inducing plasma discharge.
For example, the reactive gas RG may be O2. Exhaust materials with increased decomposition rates due to the plasma discharge may be decomposed into ions having charges. For example, the exhaust materials to which the plasma pretreatment system is applied may include N3−, O2−, H+, Mx+, C, e−(electrons), and the like. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the operation of the plasma pretreatment system and the decomposed exhaust materials differ according to the example embodiments.
The exhaust materials in an ionic state moved to the pump 32 may be recombined to form a new material. For example, the pump 32 may include mixed oxides (MOx), NO2, H2O, CO2, and the like. However, this is only an example and the present disclosure is not necessarily limited thereto, and in addition, various materials may be included. For example, the pump 32 may include H+(cations) that are not recombined.
The scrubber 33 may dissolve and discharge at least some of the remaining exhaust materials. Meanwhile, since the exhaust materials to which the plasma pretreatment system is applied are decomposed and/or substituted with a material having a relatively simple structure compared to the initial exhaust material WP, the efficiency of the scrubber 33 may be increased. For example, the exhaust material discharged to the outside through the scrubber 33 may be in the form of MOx, NO2, H2O, CO2, H2, or the like. However, this is an example and the present inventive concepts are not necessarily limited thereto, and various materials may be included.
Referring to
When the plasma pretreatment system is operated, a reactive gas may be injected into the processing chamber (S210). For example, as described above, a reactive gas may be O2. The reactive gas may be decomposed by reacting with the exhaust material discharged from the reaction chamber.
However, since an exhaust material in a form of powder that has not completely decomposed may accumulate in the pump and can shorten the lifespan of the pump, plasma discharge may be used to increase decomposition performance (S220). For example, the plasma discharge may be generated in the form of an RF plasma discharge. However, this is an example embodiment and the present disclosure is not necessarily limited thereto, and may be generated in a form of DC glow discharge or the like according to example embodiments.
In the deposition system, the plasma pretreatment system may be operated multiple times according to an example embodiment. Therefore, a step S230 of determining whether to repeatedly operate the plasma pretreatment system may be performed. Accordingly, steps S210 and S220 may be repeated multiple times. The exhaust material with increased decomposition performance by the above-described steps may be discharged through a pump and a scrubber (S240). However, as described above, this is an example embodiment and the present disclosure is not necessarily limited thereto, and the configuration of the exhaust unit and the disposition of each component may vary according to an example embodiment.
The plasma pretreatment system applied to the deposition system may operate to discharge the exhaust material with increased decomposition performance. Accordingly, it is possible to extend the lifespan of the pump by reducing the amount of exhaust material accumulated in the pump. In addition, the exhaust efficiency can be increased by increasing the efficiency of the scrubber.
Referring to
The first precursor, which is a component of the thin film to be deposited, may be filled in the first gas supply unit 320a from the first main tank 340a by the first automatic refill system ARS_a. The first gas supply unit 320a may supply a first precursor in a gaseous state to the reaction chamber 310, and the second gas supply unit 320b may supply a second precursor different from the first precursor to the reaction chamber 310 in a gaseous state.
In the deposition system 300 according to an example embodiment of the present inventive concept, the second gas supply unit 320b may include components corresponding to the first gas supply unit 320a. As an example, the second gas supply unit 320b may include a second sub tank 322b, a second liquid mass flow controller 323b, a second vaporizer 324b, and a second filter 325b. The second sub tank 322b may store the second precursor filled by the second automatic refill system ARS_b from the second main tank 340b.
The first precursor and the second precursor may react with a reactant supplied from the reactant supply unit 350 in the reaction chamber 310 to form a thin film on a substrate. Exhaust materials discharged by the deposition process may be discharged to the outside after the plasma pretreatment system shown in
Referring to
The first precursor, which is a component of the thin film to be deposited, may be filled in the first gas supply unit 420a from the first main tank 440a by the first automatic refill system ARS_a. The first gas supply unit 420a may supply a first precursor in a gaseous state to the reaction chamber 410. The second precursor, different from the first precursor, may be filled in the second sub tank 422b by the second automatic refill system ARS_b from the second main tank 440b. The second gas supply unit 420b may supply a second precursor to the reaction chamber 410 in a gaseous state.
The second gas supply unit 420b included in the deposition system 400 may vaporize a second vaporizer by using a bubbler, unlike the second gas supply unit 320b included in the deposition system 300 shown in
The first precursor and the second precursor may react with the reactant supplied from the reactant supply unit 450 in the reaction chamber 410 to form a thin film on the substrate. Exhaust materials discharged by the deposition process may be discharged to the outside after the plasma pretreatment system shown in
Other features and operations of the configuration may be the same as the deposition system 1 shown in FIG. However, this is an example and the present disclosure is not necessarily limited thereto, and the configurations of the first gas supply unit 420a and the second gas supply unit 420b may have different characteristics according to differences in physical properties between the first precursor and the second precursor.
Referring to
The first gas supply unit 520a may supply a first precursor in a gaseous state to the reaction chamber 510. The n-th gas supply unit may supply the n-th precursor in a gaseous state to the reaction chamber 510.
The number of gas supply units 520a, 520b, . . . 520n and a reactant supply unit 550 may be determined by the composition of the thin film deposited on the substrate. For example, in the case of a thin film composed of a binary material, a deposition process may be performed by a deposition system including one gas supply unit 520a and a reactant supply unit 550. In addition, in the case of a thin film made of a ternary material, a deposition process may be performed by a deposition system including two gas supply units 520a and 520b and a reactant supply unit 550. However, this is an example embodiment and the present disclosure not necessarily limited thereto, and the number of constituent elements of the thin film, the number of gas supply units 520a, 520b, . . . 520n, and the number of reactant supply units 550 may be different depending on the deposition process method.
Each of the plurality of gas supply units 520a, 520b, . . . 520n may include independent components, respectively. For example, the plurality of gas supply units 520a, 520b, . . . 520n may all be gas supply units including a vaporizer, similar to the deposition system illustrated in
In the deposition system according to an example embodiment of the present inventive concept, the first to n-th precursors respectively supplied from the n gas supply units 520a, 520b, . . . 520n may react with the reactants supplied from the reactant supply unit 550 to form a thin film on a substrate.
The exhaust materials discharged by the deposition process may be discharged to the outside after the plasma pretreatment system shown in
As set forth above, a deposition system may use an Auto Refill System (ARS) applied to a sub tank instead of periodically replacing a canister, thereby maintaining a liquid reactant solution in a state that may be supplied without interruption. In addition, by applying a plasma pretreatment system (PPS) to an exhaust unit, a lifespan of a pump can be increased and an efficiency of a scrubber can be increased.
It can be understood that when an element is referred to with terms such as “first” and “second”, the element is not limited thereby. They may be used for the purpose of distinguishing the element from the other elements, and might not limit the sequence or importance of the elements. In some cases, a first element may be referred to as a second element without departing from the scope of the claims set forth herein. Similarly, a second element may also be referred to as a first element.
The term “an example embodiment” used herein does not refer to the same example embodiment, and is provided to emphasize a particular feature or characteristic different from that of another example embodiment. However, example embodiments provided herein are considered to be able to be implemented by being combined in whole or in part one with one another. For example, one element described in a particular example embodiment, even if it is not described in another example embodiment, may be understood as a description related to another example embodiment, unless an opposite or contradictory description is provided therein.
Terms used herein are used in order to describe an example embodiment rather than limiting the present disclosure. In this case, singular forms include plural forms unless interpreted otherwise in context.
While example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present inventive concept.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0095940 | Jul 2020 | KR | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17195900 | Mar 2021 | US |
| Child | 18425048 | US |
