Patent Publication Number: US-2023144163-A1

Title: Apparatus for removing residue of euv light source vessel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority and benefit of Korean Patent Application No. 10-2021-0152049, filed on Nov. 8, 2021 with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     Inventive concepts relate to an apparatus for removing a residue of an EUV light source vessel. 
     2. Description of Related Art 
     In general, when an Extreme Ultraviolet (EUV) exposure device is used for a certain period of time, tin residues that are not discharged may adhere to an inside of the EUV light source vessel. These tin residues may interfere with normal operations of EUV light sources and must be removed periodically. However, it may take a long period of time to remove the tin residues from the EUV light source vessel, which may lower the productivity of the extreme ultraviolet exposure device. 
     SUMMARY 
     An aspect of inventive concepts is to provide an apparatus for removing a residue for an EUV light source vessel that can reduce a time for a maintenance and repair operation of the EUV light source vessel. 
     According to an embodiment of the inventive concepts, an apparatus for removing a residue of an EUV light source vessel is provided. The EUV light source vessel may include an internal side surface having a curved surface. The apparatus may include a frame portion configured to be disposed on a bottom surface of the EUV light source vessel and a head portion above the frame portion. The head portion may be configured to be rotatably moved on a circular trajectory while maintaining a desired (and/or alternatively predetermined) distance from the curved surface of the EUV light source vessel. The head portion may have a heating member configured to emit heat toward the curved surface of the EUV light source vessel. The heating member may have a shape curved in an arc corresponding to a portion of the circular trajectory in which the head portion may be configured to be rotatably moved. 
     According to an embodiment of inventive concepts, an apparatus for removing a residue of an EUV light source vessel is provided. The EUV light source vessel may include an internal side surface having a curved surface and the residue may be attached to the curved surface. The EUV light source vessel may include a frame portion configured to be disposed on a bottom surface of the EUV light source vessel, a head portion above the frame portion and configured to be rotatably moved on a circular trajectory while maintaining a desired (and/or alternatively predetermined) distance from the curved surface of the EUV light source vessel, and a controller configured to control power applied to the heating member. The head portion may include a heating member configured to emit heat toward the curved surface of the EUV light source vessel. The heating member may have a shape curved in an arc corresponding to a portion of the circular trajectory in which the head portion is configured to be rotatably moved. 
     According to an embodiment of inventive concepts, an apparatus for removing a residue of an EUV light source vessel may include a frame portion and a head portion above the frame portion. The head portion may be configured to be rotatably moved on a circular trajectory and to emit heat toward an outside of the circular trajectory. The head portion may include a heating member, a cover, and a body. The heating member may have a shape curved in an arc corresponding to a portion of the circular trajectory in which the head portion is configured to be rotatably moved. The cover may have an internal space in which the heating member is disposed. The body may support the cover and may have an opening defining a region in which the cover is exposed toward an outside of the circular trajectory. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features, and advantages of inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a schematic configuration diagram illustrating an extreme ultraviolet exposure facility in which an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts is used; 
         FIG.  2    is a schematic side view of the EUV light source vessel of  FIG.  1   ; 
         FIG.  3    is a perspective view of an apparatus for removing a residue for an EUV light source vessel according to an example embodiment; 
         FIG.  4    is a side view of the apparatus for removing a residue for a EUV light source vessel of  FIG.  3   ; 
         FIGS.  5 A and  5 B  are views illustrating various modifications of head portions of the apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts; 
         FIG.  6    is a block diagram of an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts; 
         FIG.  7    is a schematic side view illustrating a state in which the EUV light source vessel of  FIG.  2    is inserted into the apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts; and 
         FIG.  8    is a plan view illustrating a state in which the EUV light source vessel of  FIG.  2    is inserted into the apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, example embodiments of inventive concepts will be described with reference to the accompanying drawings as follows. 
     An extreme ultraviolet light source system and an extreme ultraviolet exposure facility in which an apparatus for removing a residue for an EUV light source vessel according to an example embodiment is used will be described with reference to  FIGS.  1  and  2   . 
       FIG.  1    is a schematic configuration diagram illustrating an extreme ultraviolet exposure facility in which an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts is used, and  FIG.  2    is a schematic side view of the EUV light source vessel of  FIG.  1   . 
     Referring to  FIG.  1   , an extreme ultraviolet exposure facility  1  may include an exposure chamber  90 , an extreme ultraviolet light source system SO, a lithographic apparatus LA, a projection system PS, and an upper electrostatic chuck  72 , and a lower electrostatic chuck  80 . 
     The exposure chamber  90  may have an internal space  91 , and in the internal space  91 , the extreme ultraviolet light source system SO, the lithographic apparatus LA, the projection system PS, the upper electrostatic chuck  72  and the lower electrostatic chuck  80  may be disposed. A mask  71  may be loaded/unloaded from the upper electrostatic chuck  72  by an electrostatic force generated by power applied from a power supply  73 , and a substrate W may be loaded/unloaded from the lower electrostatic chuck  80 . For example, the substrate W may be a semiconductor wafer. 
     The extreme ultraviolet light source system SO may generate extreme ultraviolet light B having a wavelength of less than about 100 nm and supply the same to the lithographic apparatus LA. The extreme ultraviolet light source system SO will be described in detail later. 
     The lithographic apparatus LA may include a plurality of mirrors to irradiate the extreme ultraviolet light B emitted from the extreme ultraviolet light source system SO in a direction of the upper electrostatic chuck  72 . Since a plurality of mirrors included in the lithographic apparatus LA have a known structure, only two mirrors  61  and  62  are shown for the sake of simplification and convenience of description. 
     The projection system PS may include a plurality of mirrors, and project a pattern of extreme ultraviolet light B reflected from a mask  71  attached to the upper electrostatic chuck  72  to the substrate W disposed on the lower electrostatic chuck  80 , to expose the pattern on a surface of the substrate W. Since the plurality of mirrors included in the projection system PS have a known structure, only the two mirrors  63  and  64  are shown for the sake of simplification and convenience of description. 
     Referring to  FIGS.  1  and  2   , the extreme ultraviolet light source system SO may include an EUV light source vessel  10  and a light source  50 . Although not illustrated, the extreme ultraviolet light source system SO may further include a droplet supply apparatus for supplying droplets DP into the EUV light source vessel  10 . 
     The EUV light source vessel  10  may include an internal vessel  20  and an external vessel  30 . The EUV light source vessel  10  may be disposed to be inclined at a desired (and/or alternatively predetermined) angle in an exposure chamber  90 . In an example embodiment, the EUV light source vessel  10  may be disposed to be inclined at an angle θ1 of about 28° with respect to a normal line, perpendicular to a bottom surface of the exposure chamber  90 . 
     The internal vessel  20  may be disposed inside the external vessel  30 . The internal vessel  20  may be a cone-shaped cover narrowing toward an upper portion thereof, and an intermediate focus IF providing a path through which the generated extreme ultraviolet light B is emitted may be located at an end portion of the cone. The internal vessel  20  may include a lower internal vessel  21  having a vane disposed on an inner surface thereof, and an upper internal vessel  22  disposed on an upper portion of the lower internal vessel  21  and having an intermediate focus IF therein. According to an example embodiment, an internal temperature sensor  23  for measuring a temperature of the internal vessel  20  may be disposed on a lower surface of the lower internal vessel  21 . The internal temperature sensor  23  may be connected to a controller  150  to be described later through wired or wireless communication. The internal temperature sensor  23  may transmit a temperature value of the internal vessel  20  to the controller  150 . 
     The external vessel  30  may include a lower external vessel  31  and an upper external vessel  32  disposed above the lower external vessel  31 . An EUV collector  40  may be disposed on a bottom surface  31 B of the lower external vessel  31 , and a door  31 D for inserting and withdrawing the EUV collector  40  may be disposed on one side surface of the lower external vessel  31 . At least a portion of the inner surface  31 S of the lower external vessel  31  may be formed of a curved surface. 
     Laser light DL oscillated from a light source  50  may be supplied into the EUV light source vessel  10  to generate extreme ultraviolet light B. Specifically, the laser light DL supplied into the EUV light source vessel  10  may be irradiated to droplets DP made of any one of tin (Sn), lithium (Li), and xenon (Xe) at a primary focus PF, to generate plasma P for radiating extreme ultraviolet light B. The EUV collector  40  disposed inside the EUV light source vessel  10  may collect the extreme ultraviolet light B radiated in all directions from the plasma P and concentrate the extreme ultraviolet light B to the intermediate focus IF, and then provide the same to the lithographic apparatus LA. 
     The droplet DP irradiated with the laser light DL explodes, leaving a residue TC in the EUV light source vessel  10 . A portion of the residue TC may be inserted into a flow path G1 between the internal vessel  20  and the external vessel  30  of the EUV light source vessel  10 . The residue TC inserted into the flow path G1 between the internal vessel  20  and the external vessel  30  may be collected in a relatively low region of the flow path G1 by gravity, and be moved along the internal side surface  31 S of the lower external vessel  31  and be accommodated in the residue collector IE and removed. However, the residue TC collected in the lower region may be easily cooled and adhered to the internal side surface  31 S of the lower external vessel  31 . The residue TC adhered to the internal side surface  31 S may block the flow path G1, and may interfere with a normal operation of the extreme ultraviolet light source system SO. The apparatus for removing a residue for an EUV light source vessel according to an example embodiment may be used to heat and remove the residue TC adhered to the extreme ultraviolet light source system SO. 
     An apparatus for removing a residue for an EUV light source vessel  100  according to an example embodiment will be described with reference to  FIGS.  3  to  6   .  FIG.  3    is a perspective view of an apparatus for removing a residue for an EUV light source vessel, and  FIG.  4    is a side view of the apparatus for removing a residue for an EUV light source vessel of  FIG.  3   .  FIGS.  5 A and  5 B  are views illustrating various modifications of head portions of an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts.  FIG.  6    is a block diagram of an apparatus for removing a residue for an EUV light source vessel according to an example embodiment. 
     Referring to  FIGS.  3  and  4   , the apparatus for removing a residue for an EUV light source vessel  100  may include a frame portion  110  and a head portion  140  installed on the frame portion  110 . In addition, referring to  FIG.  6   , each configuration of the apparatus for removing a residue for an EUV light source vessel  100  may be controlled by a controller  150 . 
     The controller  150  may be disposed inside the apparatus for removing a residue for an EUV light source vessel  100 , or may be separately disposed outside the apparatus for removing a residue for an EUV light source vessel  100 . The controller  150  is for controlling an overall operation of the apparatus for removing a residue for an EUV light source vessel  100 , and may control operations of a heating member  143 , a head portion temperature sensor  144 , a camera  145 , a rotation shaft driver  131 , a head portion driver  135 , and a support driver  133 . In addition, the controller  150  may receive a temperature value of the internal vessel  20  from the internal temperature sensor  23  disposed in the internal vessel  20 . For example, the controller  150  may be implemented with processing circuitry such as a processor such as a central processing unit (CPU), a graphic processing unit (GPU), a microprocessor, an application specific integrated circuit (ASIC), or a field programmable gate arrays (FPGA). In addition, the controller  150  may include a memory for storing various data necessary for the operation of the apparatus for removing a residue for an EUV light source vessel  100 . 
     The frame portion  110  is a support for installing the head portion  140 , and may move the head portion  140 . The frame portion  110  may include a first plate  112 , a second plate  114 , a lifting assembly  120 , and a rotation hardware assembly  130 . However, inventive concepts are not limited thereto, and the configuration of the frame portion  110  may be variously modified. 
     For example, the first plate  112  may have a rectangular plate shape. The first plate  112  may have a size that can be inserted into and withdrawn from the EUV light source vessel  10  through the door  31 D described above. 
     The second plate  114  may be disposed to be spaced apart from the first plate  112 . In addition, the second plate  114  may have a shape corresponding to the first plate  112 . For example, the second plate  114  may have a rectangular plate shape, and may have a size corresponding to the size of the first plate  112 . A lifting assembly  120  may be disposed between the first plate  112  and the second plate  114 . 
     The lifting assembly  120  may raise and lower the second plate  114  to adjust a vertical height of the head portion  140  disposed on the second plate  114 . 
     For example, the lifting assembly  120  may include a folding member  122  and a connecting bar  128 . The folding member  122  may have one end connected to the first plate  112  and the other end connected to the second plate  114 . According to an example embodiment, the folding member  122  may be installed at a front end portion and a rear end portion of the first and second plates  112  and  114 , respectively. However, inventive concepts are not limited thereto, and only one folding member  122  may be disposed in a central portion the first and second plates  112  and  114 . The folding member  122  may include a folding link portion  125  having one end connected to the first plate  112  and the other end connected to the second plate  114  and a connection portion  126  connecting the folding link portion  125  and through which the connection bar  128  is installed. 
     The folding link portion  125  is disposed to form a pair on both side surfaces of the first and second plates  112  and  114 , and the connection portion  126  connects the folding link portion  125 . Meanwhile, the connection portion  126  may be provided with a through hole (not shown) through which the connecting bar  128  is disposed. A screw portion (not shown) may be formed in the through hole so that the connection portion  126  may be moved when the connection portion  126  rotates. 
     The connecting bar  128  may be connected to the folding member  122  and can fold the folding member  122  by rotation. That is, when the connecting bar  128  is rotated, the connection portion  126  of the folding member  122  may move along the connecting bar  128 . Accordingly, the second plate  114  may be raised and lowered while the folding link portion  125  installed in the connection portion  126  is folded. The connecting bar  128  may be rotated manually or may be rotated by a driver such as a motor. 
     The rotation hardware assembly  130  may be installed on an upper surface of the second plate  114 , and may be connected to the head portion  140  to rotate the head portion  140 . 
     The rotation hardware assembly  130  may include a rotation shaft  132  and a support  134 . According to an example embodiment, a rotation shaft driver  131  for rotationally driving the rotation shaft  132  may be further disposed below the rotation shaft  132 . In addition, according to an example embodiment, a support driver  133  for linearly driving the support  134  back and forth may be further disposed on an upper portion of the rotation shaft  132 . In addition, according to an example embodiment, a head portion driver  135  for tilting the head portion  140  may be further disposed at an end portion of the support  134 . The rotation shaft driver  131 , the head portion driver  135 , and the support driver  133  may be controlled by the controller  150 . Features of the rotation hardware assembly  130  may be moved and rotating using a motor, but are not limited thereto. 
     The rotation shaft  132  may be vertically disposed on an upper surface of the second plate  114 , and the support  134  may be horizontally connected to the rotation shaft  132 , and rotatably moved according to the rotation of the rotation shaft  132 . The rotation shaft  132  may be installed at a position that can be disposed at a center C of the EUV light source vessel  10  when the apparatus for removing a residue for an EUV light source vessel  100  is inserted into the EUV light source vessel  10 . Accordingly, as the rotation shaft  132  rotates, the head portion  140  may rotate while maintaining a desired (and/or alternatively predetermined) distance from the internal side surface  31 S of the EUV light source vessel  10 . 
     The head portion  140  may be disposed above the frame portion  110 , and may be used to heat the residue TC adhered to the internal side surface  31 S of the EUV light source vessel  10 . The head portion  140  may be connected to the rotation hardware assembly  130  and may be rotatably installed along a circular trajectory CT while maintaining a desired (and/or alternatively predetermined) distance from the internal side surface  31 S of the EUV light source vessel  10  (see  FIG.  8   ). In addition, the head portion  140  may emit heat toward the internal side surface  31 S of the EUV light source vessel  10 , which is outside the circular trajectory CT. In an example embodiment, a case in which the apparatus for removing a residue for an EUV light source vessel  100  include one head portion  140  is described as an example, but inventive concepts are not limited thereto, and a plurality of head portions  140  may be provided. In this case, the plurality of head portions  140  may be arranged along the circular trajectory CT to correspond to the shape of the internal side surface  31 S of the EUV light source vessel  10 . The head portion  140  may have a small thickness T so that it can be inserted into a narrow space between the lower internal vessel  21  and the residue collector IE among the inside of the EUV light source vessel  10  (see  FIG.  5 A ). For example, the thickness T of the head portion  140  may be about 10 cm or less. In some embodiments, the thickness T of the head portion  140  may be about 5 to 8 cm. 
     The head portion  140  may include a body  141 , a cover  142 , and a heating member  143 . In addition, the head portion  140  may further include a camera  145  and a head portion temperature sensor  144 . In addition, according to an example embodiment, the head portion  140  may further include a cooling device (e.g., fan, thermoelectric device) for limiting and/or preventing the head portion  140  from being overheated. 
     The heating member  143  is a member capable of generating high-temperature heat, and in an example embodiment, the heating member  143  may be formed of a halogen lamp. However, inventive concepts are not limited thereto, and the heating member  143  may be formed of a coil emitting heat by an induced current. 
     The heating member  143  may be controlled to generate heat equal to or greater than a melting point at which a residue TC of the internal side surface  31 S of the EUV light source vessel  10  is melted. When the residue TC is tin, the heating member  143  may be controlled to generate heat of 232° C. or higher, which is a melting point of tin. 
     Meanwhile, the heating member  143  may be formed to have a curved surface corresponding to the internal side surface  31 S of the EUV light source vessel  10 . The heating member  143  may be formed in a shape capable of maintaining a desired (and/or alternatively predetermined) distance G2 with the internal side surface  31 S of the EUV light source vessel  10  when the head portion  140  rotates along a circular trajectory CT (see  FIG.  8   ). For example, the heating member  143  may have a shape curved in an arc, a portion of the circular trajectory CT in which the head portion  140  rotates. 
     The cover  142  may be formed in a long hollow tube shape in one direction while surrounding a heating member  143 , and the heating member  143  may be disposed on a central axis of the hollow tube. That is, the cover  142  may have a shape in which a central axis is curved in an arc to correspond to the shape of the heating member  143 . 
     The cover  142  may be made of a light-transmitting material that can protect the heating member  143  while effectively transmitting heat emitted from the heating member  143 . For example, the cover  142  may be a quartz glass tube. 
     Referring to  FIG.  5 A , a reflective surface RF1 for reflecting heat emitted from the heating member  143  toward a front surface thereof may be formed on an inner surface  142 IS of the cover  142 . The reflective surface RF1 may be disposed so that heat emitted from the heating member  143  is reflected in a specific direction. However, depending on example embodiments, a reflective surface RF2 may be disposed on an outer surface  1420 S of the cover  142  (refer to  FIG.  5 B ). In this case, a reflective surface RF2 may be formed directly on the outer surface  1420 S of the cover  142 , or may be formed on an internal side surface of the body  141  in contact with the cover  142 . 
     The body  141  is a support for fixing the cover  142  and the heating member  143 , and may be a housing formed of a metal material having excellent heating efficiency. A cover  142 , a curved hollow, may be coupled on a front surface of the body  141 , and a curved heating member  143  may be disposed along a central axis of the cover  142 . A support  134  may be connected to a rear surface of the body  141 . A front surface  141 F of the body  141  is formed in a curved surface similar to the shape of the cover  142  and the heating member  143 , and when the head portion  140  rotates along the circular trajectory CT, the front surface  141 F of the body  141  may maintain a desired (and/or alternatively predetermined) distance from the inner surface  31 S of the EUV light source vessel  10  (refer to  FIG.  8   ). 
     Referring to  FIG.  5 A , an opening  1410  for limiting an irradiation range RA of heat emitted from the heating member  143  may be formed on a front surface of the body  141 . The opening  1410  may be formed to face upwards of a front surface of the body  141  so that a main direction RD of heat irradiated through the opening  1410  forms a desired (and/or alternatively predetermined) angle θ2. In the case of an example embodiment, the desired (and/or alternatively predetermined) angle θ2 is an angle toward a region to which the residue TC is easily fixed among the inner surface  31 S of the EUV light source vessel  10 , and may be about 60°. 
     Meanwhile, the head portion  140  may further include a head portion temperature sensor  144 , such as a thermocouple or a thermistor. In an example embodiment, a case in which the head portion temperature sensor  144  is disposed on an upper surface of the head portion  140  will be described as an example, but inventive concepts are not limited thereto. The head portion temperature sensor  144  may measure a temperature of the head portion  140  and/or a temperature of the heating member  143 . The head portion temperature sensor  144  may be connected to a controller  150  and transmit the measured temperature of the head portion  140  and/or a temperature value of the heating member  143  to the controller  150 . The controller  150  may control power applied to the heating member  143  based on the temperature of the head portion  140  and/or the temperature of the heating member  143  to limit and/or prevent overheating of the head portion  140 , and the temperature of the heating member  143  may be controlled. 
     In addition, the head portion  140  may further include a camera  145 . The camera  145  may be disposed to face an upper portion of a front surface of the head portion  140 , to form an image of one region of the internal side surface  31 S of the EUV light source vessel  10 . The camera  145  may be connected to a controller  150  and transmit the formed image to the controller  150 . The controller  150  may image-process the image received from the camera  145  to detect a position of the residue TC in the formed image. 
     Hereinafter, an operation of an apparatus for removing a residue of an EUV light source vessel according to an example embodiment will be described with reference to  FIGS.  7  and  8   . 
       FIG.  7    is a schematic side view illustrating a state in which an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts is inserted into the EUV light source vessel of  FIG.  2   , and  FIG.  8    is a plan view illustrating a state in which an apparatus for removing a residue for an EUV light source vessel according to an example embodiment of inventive concepts is inserted into the EUV light source vessel of  FIG.  2   . 
     Referring to  FIGS.  7  and  8   , the apparatus for removing a residue for an EUV light source vessel  100  according to an example embodiment may be used for a maintenance and repair operation of the EUV light source vessel  10  according to an example embodiment. An EUV collector  40  of the EUV light source vessel  10  may be removed in advance before the maintenance and repair operation is performed. The apparatus for removing a residue for an EUV light source vessel  100  may be loaded on the loading plate  14  and inserted into the EUV light source vessel  10  through the door  31 D. A loading plate  14  may be provided with a stepped portion that is fixedly attached to a bottom surface  31 B of the EUV light source vessel  10  at one end thereof. The apparatus for removing a residue for an EUV light source vessel  100  may be disposed such that a rotation shaft  132  for rotatably moving a head portion  140  is aligned with a center C of the EUV light source vessel  10 . In this case, the head portion  140  may be disposed to be positioned between a lower inner vessel  21  and a residue collector IE. A distance G2 between the head portion  140  and an internal side surface  31 S of the EUV light source vessel  10  may be adjusted to a size that the head portion  140  can be rotated while maintaining the distance G2 from the internal side surface  31 S of the EUV light source vessel  10 . 
     The head portion  140  may irradiate light to the internal side surface  31 S of the EUV light source vessel  10  through the heating member  143 , and heat a residue TC adhering to the internal side surface  31 S of the EUV light source vessel  10  and melt the same. The molten residue TC may descend along the internal side surface  31 S to be accommodated in the residue collector IE, and the residue TC accommodated in the residue collector IE may be removed after the maintenance and repair operation is completed. 
     The controller  150  may control a rotation shaft driver  131  so that the head portion  140  rotatably moves along the inner surface  31 S of the EUV light source vessel  10 . In addition, the controller  150  may control the heating member  143  to adjust a temperature and an irradiation time of light irradiated from the heating member  143 . The controller  150  may rotatably move the head portion  140  along the internal side surface  31 S, and control to irradiate light, but may also control to irradiate light in a state in which the head portion  140  is stopped after the head portion is rotatably moved along the internal side surface  31 S. 
     In addition, the controller  150  may detect a position of a residue TC by image processing an image transmitted from a camera  145 , and control a region to which the residue TC is attached to be intensively heated by moving the head portion  140  to the detected position. According to an example embodiment, the controller  150  may control the head portion  140  to make a pendulum movement based on the detected position of the residue TC. 
     In addition, the controller  150  may control power applied to the heating member  143  with reference to a temperature value (or other parameter or signal) transmitted from an internal temperature sensor  23  and a head portion temperature sensor  144 . The controller  150  may cut off the power when the temperature value transmitted from the internal temperature sensor  23  exceeds a first reference threshold (e.g., first reference temperature). For example, the first reference threshold may be a first reference temperature of about 1000° C. In addition, when a temperature value transmitted from the head portion temperature sensor  144  of the controller  150  exceeds a second reference threshold (e.g., second reference temperature), power may be cut off. For example, the second reference threshold (e.g., second reference threshold) may be lower than the first reference threshold (e.g., first reference threshold). The second reference threshold may be a second reference temperature of about 300° C. 
     Thereafter, when a maintenance and repair operation is completed, the apparatus for removing a residue for an EUV light source vessel  100  may be withdrawn from an EUV light source vessel  10  through a door  31 D. 
     As described above, the apparatus for removing a residue for an EUV light source vessel  100  may melt a residue TC attached to the EUV light source vessel  10 , so that the residue TC may be easily removed. Accordingly, a time consumed for maintenance and repair of the EUV light source vessel  10  may be saved. 
     As set forth above, according to inventive concepts, an apparatus for removing a residue for an EUV light source vessel that can reduce a time required for a maintenance and repair operation of the EUV light source vessel may be provided. 
     Herein, a lower side, a lower portion, a lower surface, and the like, are used to refer to a direction toward a mounting surface of the fan-out semiconductor package in relation to cross-sections of the drawings, while an upper side, an upper portion, an upper surface, and the like, are used to refer to a direction opposite to the direction. However, these directions are defined for convenience of explanation, and the claims are not limited by the directions defined as described above. 
     The meaning of a “connection” of a component to another component in the description includes an indirect connection through an adhesive layer as well as a direct connection between two components. In addition, “electrically connected” conceptually includes a physical connection and a physical disconnection. 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 only for a purpose of distinguishing the element from the other elements, and may 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. 
     One or more of the elements disclosed above may include or be implemented in processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. 
     Terms used herein are used only in order to describe example embodiments 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 inventive concepts as defined by the appended claims.