Patent Publication Number: US-10779388-B2

Title: EUV generation device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 to and the benefit of Korean Patent Application No. 10-2018-0092377, filed on Aug. 8, 2018, in the Korean Intellectual Property Office (KIPO), the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Example embodiments of the inventive concepts relate to an extreme ultraviolet (EUV) generation device having improved light emitting efficiency. 
     2. Discussion of Related Art 
     An extreme ultraviolet (EUV) generation device is a device which generates plasma using lasers and then generates and supplies EUV rays using the generated plasma. The EUV generation device generates the plasma by focusing lasers on a flow path through which a plasma gas flows and emitting lasers toward the plasma gas. 
     Meanwhile, as a size of a pattern on a semiconductor substrate decreases, a semiconductor process such as a photolithography process needs light having a wavelength shorter than those of general ultraviolet (UV) rays. Since EUV rays have a wavelength shorter than UV rays, they are applied to a light exposure process or an inspection process of a photolithography process. However, when the EUV generation device generates plasma using lasers, since the energy intensity of the generated plasma gas may be low, the intensity of the EUV rays generated therefrom may not be adequate for the light exposure process or the inspection process. 
     SUMMARY 
     Example embodiments of the inventive concepts are directed to providing an extreme ultraviolet (EUV) generation device which improves output intensity and emitting efficiency of EUV rays. 
     According to example embodiments, there is provided an EUV generation device including a housing including a housing body and an window formed on one side of the housing body, the housing body configured to connect to a vacuum pump such that an inside of the housing body is maintainable in a vacuum state; a laser source configured to emit lasers toward the inside of the housing body through the window; a plasma generation device inside the housing body, the plasma generation device configured to generate plasma in response to the lasers being emitted toward a plasma gas flowing into a laser focal area; and a radio frequency (RF) power supply device configured to preionize the plasma gas before the plasma gas flows into the laser focal area. 
     According to example embodiments, there is provided an EUV generation device configured to generate EUV rays by using a laser generation plasma method, the EUV generation device comprising: a plasma generation device configured to preionize a plasma gas to generate preionized plasma gas, and to generate plasma by emitting lasers toward the preionized plasma gas. 
     According to example embodiments, there is provided an EUV generation device including a laser source configured to emit lasers towards a laser focal area; a plasma generation device configured to generate plasma by directing a plasma gas to flow into the laser focal area; a radio frequency (RF) power supply device configured to preionize the plasma gas to before the plasma gas flows into the laser focal area to generate preionized plasma gas; and an electromagnet configured to focus the preionized plasma gas to the laser focal area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the inventive concepts will become more apparent to those of ordinary skill in the art by describing some example embodiments thereof in detail with reference to the accompanying drawings, in which: 
         FIGS. 1A and 1B  are schematic configuration diagrams illustrating an EUV generation device according to an example embodiment of the inventive concepts. 
         FIG. 2  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
         FIG. 3  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
         FIG. 4  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
         FIG. 5  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
         FIG. 6  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
         FIG. 7  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, extreme ultraviolet (EUV) generation devices according to example embodiments of the inventive concepts will be described. 
       FIGS. 1A and 1B  are schematic configuration diagrams illustrating an EUV generation device according to an example embodiment of the inventive concepts. 
     Referring to  FIGS. 1A and 1B , an EUV generation device  100  according to an example embodiment of the inventive concepts, may include a housing module  110 , a laser source  120 , a plasma generation module  130 , and a radio frequency (RF) power supply module  140 . Also, the EUV generation device  100  may further include a vacuum pump  180  and a gas source  190 . Meanwhile, the EUV generation device  100 , although not shown in detail, may further include a condensing module (not shown) for condensing generated EUV rays and a filter module (not shown) for selecting only a wavelength necessary for the generated EUV rays. 
     The EUV generation device  100  is a device which emits a laser toward a plasma gas to generate plasma and then generates and supplies EUV rays using the generated plasma. The EUV generation device  100  may generate EUV rays by using a laser produced plasma (LPP) method. The EUV rays may have a wavelength of 10 nm to 0 nm. The EUV rays may have a wavelength of 10 nm to 20 nm. The EUV rays may have a wavelength of 13.5 nm. 
     As discussed below, in one or more example embodiments, the EUV generation device  100  may preionize a plasma gas by applying energy to the plasma gas before emitting a laser to generate the plasma. That is, the EUV generation device  100  may change the plasma gas to a preionized state by applying an electric field using an inductively coupled induced current and subsequently generate the plasma by emitting the laser to the preionized plasma gas. Here, the preionized state may refer to a state in which a plasma gas is partially or entirely ionized, that is, a state in which energy is lower than energy needed for generating plasma. Also, the preionized state may include a state in which the plasma gas is preheated. 
     Accordingly, since in one or more example embodiments, the EUV generation device  100  generates plasma by emitting a laser to the plasma gas in the preionized state formed by using an electric field caused by an induced current, EUV rays may be more efficiently generated. That is, the EUV generation device  100  may increase output intensity and emission efficiency of EUV rays. 
     The EUV generation device  100  may be applied to a variety of devices which perform a semiconductor process, such as a lithography process. For example, the EUV generation device  100  may be used for light exposure equipment in which a light exposure process is performed. In this case, the EUV generation device  100  may provide EUV rays as light exposure beams which perform a light exposure process. Also, the EUV generation device  100  may be used for an inspection device which inspects reticles. 
     The housing module  110  may include a housing body  111 , an incident window  112 , and an exit window  113 . Although not shown in the drawings, the housing module  110  may further include a vacuum gage which measures an internal vacuum level of the housing body  111 . 
     The housing body  111  is formed as a box shape with a hollow therein. The housing body  111  provides a space in which the plasma generation module  130  is accommodated. The housing body  111  provides an internal space in which EUV rays are generated. The housing body  111  may be formed of a material having thermal resistance and corrosion resistance, such as stainless steel. Since the housing body  111  is exposed to plasma at a high temperature, the housing body  111  may be formed of a material which is not damaged by the plasma at a high temperature. 
     The housing body  111  may be maintained in a vacuum therein. The housing body  111  may remain at an adequate vacuum level to prevent lasers or EUV rays from being absorbed into atmosphere during a process of forming EUV rays. For example, the housing body  111  may remain at a vacuum level of 10 −3  torr or less. Also, the housing body  111  has an outside in contact with the atmosphere and may be combined with an optical vacuum chamber (not shown) at the exit window  113 . Here, the optical vacuum chamber may be a reticle inspection chamber using generated EUV rays. Also, the housing body  111  may be located in an additional vacuum chamber. 
     The incident window  112  may be formed on one side of the housing body  111 . The incident window  112  may provide a path through which a laser passes. Also, the incident window  112  may perform a function of separating the housing body  111  from an external environment. For example, when the housing body  111  is located in the atmosphere, the incident window  112  separates an internal space of the housing body  111  from the outside so as to maintain a vacuum state inside the housing body  111 . The incident window  112  may be formed of a material which reduces (or, alternatively, minimizes) a loss of an incident laser. The incident window  112  may be formed of quartz and may separate the inside of the housing body  111  from the outside to pass a laser therethrough. Meanwhile, when the outside of the housing body  111  is in a vacuum state, the incident window  112  may be omitted. In this case, the incident window  112  may be formed as an empty hole. 
     The exit window  113  may be formed on the other side of the housing body  111 . The exit window  113  may provide a path through which EUV rays pass. When the housing body  111  is connected to an additional optical process chamber (not shown) through the exit window  113 , the exit window  113  may be formed as an empty hole. Also, the exit window  113  may be formed as an optical filter which passes only EUV rays and blocks lasers therethrough. The exit window  113  may be formed as a filter including zirconium. Also, the exit window  113  may perform a function of separating the housing body  111  from an external environment. For example, when the housing body  111  is located in the atmosphere, the exit window  113  separates an internal space of the housing body  111  from the outside so as to maintain a vacuum state inside the housing body  111 . The exit window  113  may be formed of a material which reduces (or, alternatively, minimizes) a loss of EUV rays which exit therefrom. The incident window  112  and the exit window  113  may be installed in the housing body  111  at a variety of positions depending on positions of the plasma generation module  130 , the RF power supply module  140 , or other components in the housing body  111 . 
     The vacuum pump may be connected to the housing body  111  and may maintain a vacuum inside the housing body  111 . The vacuum pump may include a variety of vacuum pumps adequate for maintaining a vacuum level of, for example, 10 −3  torr, inside the housing body  111 . 
     The laser source  120  is a source which outputs lasers. The laser source  120  may be located outside the housing body  111  and may emit lasers toward the incident window  112 . The laser source  120  may output lasers having energy sufficient for making a plasma gas enter in a plasma state. Lasers emitted by the laser source  120  may form a focal point in a laser focal area (labeled “a”) located in the plasma generation module  130  and may efficiently heat the plasma gas. As discussed in more detail below, since the plasma gas is preionized by the RF power supply module  140 , it is possible to more efficiently generate plasma than when lasers are emitted theretoward. The lasers may have high-intensity pulses. The lasers may be CO 2  lasers, NdYAG lasers, or titanium sapphire lasers. Also, the lasers may be ArF excimer lasers or KrF excimer lasers. 
     The laser source  120  may further include a focal lens  121 . The focal lens  121  may be located between the laser source  120  and the housing body  111 . The focal lens  121  may adjust a focal length of lasers emitted by the laser source  120 . As the focal lens  121 , a general focal lens may be used. 
     The plasma generation module  130  may include a laser path pipe  131  and a gas supply pipe  132 . The plasma generation module  130  may further include a gas focusing pipe  133 . The plasma generation module  130  forms plasma and generates EUV rays by using lasers and a plasma gas. In more detail, the plasma generation module  130  may be located in the housing body  111  and may generate plasma by emitting lasers toward a plasma gas which flows into the laser focal area “a.” 
     The laser path pipe  131  may be formed to have a pipe shape which includes a hollow and open one and other sides. The laser path pipe  131  may be formed as a pipe having an inner diameter which is a first diameter D 1 . The laser path pipe  131  may be located in the housing body  111  such that a central axis coincides with a center of the incident window  112 . The laser path pipe  131  may be located in the housing body  111  such that the central axis coincides with an emission path. A laser may be incident on one side and may exit from the other side of the laser path pipe  131 . In the laser path pipe  131 , since a laser is emitted along the central axis, the laser focal area a may be formed at a position on the central axis. That is, in the laser path pipe  131 , since an emission direction of the laser is equal to a flow direction of a plasma gas supplied by the gas supply pipe  132 , the laser focal area “a” may be easily formed in a desired area. For example, the laser focal area “a,” in which lasers are condensed, may be formed in the laser path pipe  131 . The laser focal area a may be formed inside or outside the other side of the laser path pipe  131 . Also, the laser focal area “a” may be formed at a position at which the gas supply pipe  132  is combined with the laser path pipe  131 . 
     The laser path pipe  131  may be formed as a dielectric. The laser path pipe  131  may be formed of a transparent material such as quartz. Also, the laser path pipe  131  may be formed of alumina or a ceramic material such as zirconia. 
     The laser path pipe  131  may remain in a vacuum state so as to reduce (or, alternatively, prevent) a loss caused by scattering of lasers and efficiently form plasma. The laser path pipe  131  may be located inside the housing body  111  so as to maintain a vacuum state thereinside. Also, although not shown in detail in the drawings, air in the laser path pipe  131  may be discharged through an additional discharge pipe such that a vacuum state thereinside may be maintained. 
     A reflecting mirror (not shown), which reflects or condenses generated EUV rays, may be further included between the other side of the laser path pipe  131  and the exit window  113 . In this case, a central axis of the laser path pipe  131  may not coincide with the center of the exit window  113 . 
     The gas supply pipe  132  may be formed to have a pipe shape which includes a hollow and open top and bottom sides. The gas supply pipe  132  may be formed to have an inner diameter which is a second diameter D 2 . The gas supply pipe  132  may be formed of the same material as that of the laser path pipe  131 . The gas supply pipe  132  may be combined with the laser path pipe  131  to be perpendicular, or to slant thereto. That is, the gas supply pipe  132  may be combined such that the central axis thereof is perpendicular to or intersects with the central axis of the laser path pipe  131  at a slant. A top of the gas supply pipe  132  may be combined with the laser path pipe  131  while passing through from an outer circumferential surface to an inner circumferential surface of the laser path pipe  131 . The inside of the gas supply pipe  132  may be combined with the inside of the laser path pipe  131 . The gas supply pipe  132  may be combined with the laser path pipe  131  at an intermediate position on the basis of a longitudinal direction of the laser path pipe  131 . When the laser focal area “a” is formed on the other end of the laser path pipe  131 , the gas supply pipe  132  may be combined with the laser path pipe  131  while tilting toward the other end. That is, the gas supply pipe  132  may be combined with the laser path pipe  131  while the bottom side rotates about the top side, combined with the laser path pipe  131 , toward the one side of the laser path pipe  131 . In this case, the plasma gas supplied by the gas supply pipe  132  may more efficiently flow toward the other side of the laser path pipe  131 . 
     The gas supply pipe  132  may supply the plasma gas to the inside of the laser path pipe  131 . The second diameter of the gas supply pipe  132  may be greater than the first diameter of the laser path pipe  131 . The second diameter may be 1.1 to 2.0 times the first diameter. Accordingly, an amount of the plasma gas supplied by the gas supply pipe  132  is larger than an amount of the gas which flows in the laser path pipe  131 . Also, the plasma gas may flow throughout the laser path pipe  131  at a uniform density. 
     The gas focusing pipe  133  may have a pipe shape which is open from a first side to a second side and has an inner diameter which decreases from the first side toward the second side. The gas focusing pipe  133  may be integrally formed with the laser path pipe  131 . The second end of the gas focusing pipe  133  may have an inner diameter smaller than an inner diameter of the gas supply pipe  132 . The first end of the gas focusing pipe  133  may be combined with the other end of the laser path pipe  131 . The gas focusing pipe  133  focuses a plasma gas, which flows in from the laser path pipe  131 , while allowing the plasma gas to flow from one side to the other side. That is, the gas focusing pipe  133  may increase density of the plasma gas, which flows thereinto. Since the inner diameter of the second end of the gas focusing pipe  133  is formed to be smaller than the inner diameter of the laser path pipe  131 , the plasma gas may be more efficiently focused. When the gas focusing pipe  133  is formed, the laser focal area “a” may be formed inside or outside the gas focusing pipe  133  instead of the inside of the laser path pipe  131 . The laser focal area “a” may be formed inside or outside the second end of the gas focusing pipe  133 . The gas focusing pipe  133  may increase efficiency of forming plasma by increasing the density of the plasma gas in the laser focal area “a.” Meanwhile, when it is possible to focus the plasma gas due to the inner diameter of the laser path pipe  131  being adequately small, the gas focusing pipe  133  may be omitted. 
     The RF power supply module  140  may include an RF coil  141  and an RF power source  142 . The RF power supply module  140  may preionize the plasma gas before the plasma gas flows into the laser focal area a. 
     The RF coil  141  may be wound at least once on an outer circumferential surface of the gas supply pipe  132 . The RF coil  141  may be wound an adequate number of times for preionizing the plasma gas, which flows in the gas supply pipe  132 , or for supplying energy for plasma generation. The RF coil  141  may generate an inductive-coupling type induced current and may apply an electric field to the plasma gas. 
     The RF power source  142  may be electrically connected to the RF coil  141 . The RF power source  142  may supply power for preionization of the plasma gas to the RF coil  141 . The RF power source  142  may supply power having a frequency of, for example, 13.5 MHz to 80 MHz. 
     The vacuum pump  180  may be connected to the housing body  111  and may maintain a vacuum inside the housing body  111 . The vacuum pump may be connected to the laser path pipe  131  and may maintain a vacuum inside the laser path pipe  131 . An adequate vacuum pump may be used according to a necessary vacuum level. 
     The gas source  190  may be connected to the gas supply pipe  132  and may supply a plasma gas to the gas supply pipe  132 . Ne, He, Ar, or Xe gas may be used as the plasma gas. 
     As illustrated in  FIG. 1A , in some example embodiments, the RF coil  141  may be wound on the outer circumferential surface of the gas supply pipe  132 . However, as discussed below with reference to  FIG. 1B  to  FIG. 7 , example embodiments are not limited thereto. 
     Referring to  FIG. 1B , in an EUV generation device  200  according to another example embodiment of the inventive concepts, an RF coil  241  of the RF power supply module  240  may be wound on the other side of the laser path pipe  131 . That is, the RF coil  241  may be wound on the outer circumferential surface of the laser path pipe  131  between the other end of the laser path pipe  131  and the gas focusing pipe  133 . The RF coil  241  may preionize the plasma gas at a position adjacent to the laser focal area a. Accordingly, the EUV generation device  200  may more efficiently form plasma so as to increase light emission efficiency. 
     Meanwhile, in the EUV generation device  200 , although not shown in detail in the drawing, the RF coil  141  may even be wound on a position which is the same as that in  FIG. 1A . 
     Hereinafter, EUV generation devices according to other example embodiments of the inventive concepts will be described. 
       FIG. 2  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concept. 
     Referring to  FIG. 2 , an EUV generation device  300  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , the plasma generation module  130 , an RF power supply module  240 , and an electromagnet  350 . 
     In comparison to the EUV generation devices  100  and  200  shown in  FIGS. 1A and 1B , the EUV generation device  300  may be equally or similarly formed except for the electromagnet  350  also being included therein. Accordingly, hereinafter, the electromagnet  350  of the EUV generation device  300  will be mainly described. Also, in describing the EUV generation device  300 , components equal or similar to those of the EUV generation devices  100  and  200  shown in  FIGS. 1A and 1B  will be referred to with the same reference numerals and a detailed description thereof will be omitted. Meanwhile, it is the same in other following example embodiments. 
     The electromagnet  350  may have a ring shape formed of a wound coil. The electromagnet  350 , although not shown in detail, may include an annular case, an annular magnet core located in the case, and a coil wound on the magnet core. The coil may be annularly wound on the magnet core. The electromagnet  350  may have an inner diameter corresponding to or greater than an outer diameter of the laser path pipe  131 . The electromagnet  350  may have an adequate length for focusing a plasma gas. The length of the electromagnet  350  may be determined empirically. The electromagnet  350  may be located such that one side thereof comes into contact with or partially overlaps the other side of the laser path pipe  131 . 
     The electromagnet  350  may be located such that a central axis thereof coincides with the central axis of the laser path pipe  131 . The laser focal area “a” may be located at the central axis of the electromagnet  350 . The electromagnet  350  may receive power from an additional external power source (not shown) and may generate a magnetic field. However, example embodiments are not limited thereto, and the electromagnet  350  may share a power source with other components of the EUV generation device  300 . The electromagnet  350  may apply a magnetic force to an area including the laser focal area “a.” That is, the electromagnet  350  may apply a magnetic force to a plasma gas which flows into the laser focal area a. The electromagnet  350  may focus a preionized plasma gas, which flows in from the other side of the laser path pipe  131 , in the area including the laser focal area a by using a magnetic force. That is, the electromagnet  350  may increase density of the plasma gas in the area including the laser focal area “a.” Since the plasma gas changes to an ionized state in the laser path pipe  131  or the gas supply pipe  132 , the plasma gas may be focused by a magnetic force of the magnetic field. 
     When the gas focusing pipe  133  is combined with the other side of the laser path pipe  131 , the electromagnet  350  may be located to surround at least an outer circumferential surface of the gas focusing pipe  133 . The electromagnet  350  may have a length longer than that of the gas focusing pipe  133  and may be combined to surround an area including the outer circumferential surface of the gas focusing pipe  133 . Also, the electromagnet  350  may have an inner diameter corresponding to the inner diameter of the gas focusing pipe  133 . Accordingly, one side of the electromagnet  350  may come into contact with and be combined with the second end of the gas focusing pipe  133 . The laser focal area “a” may be formed inside the gas focusing pipe  133  or the electromagnet  350 . 
     Hereinafter, an EUV generation device according to another example embodiment of the inventive concepts will be described. 
       FIG. 3  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
     Referring to  FIG. 3 , an EUV generation device  400  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , a plasma generation module  430 , the RF power supply module  240 , and the electromagnet  350 . 
     The plasma generation module  430  may include the laser path pipe  131 , the gas supply pipe  132 , the gas focusing pipe  133 , and a gas induction pipe  434 . 
     The gas induction pipe  434  may have an inner diameter corresponding to an inner diameter of the second end of the gas focusing pipe  133 . The gas induction pipe  434  may be integrally formed with the laser path pipe  131  and the gas focusing pipe  133 . The gas induction pipe  434  may have an outer diameter corresponding to an inner diameter of the electromagnet  350 . The gas induction pipe  434  may have at least a length corresponding to a length of the electromagnet  350 . One side of the gas induction pipe  434  may be combined with the second end of the gas focusing pipe  133  and may extend toward an inside of the electromagnet  350 . The gas induction pipe  434  may induce a plasma gas, which flows in from the gas focusing pipe  133 , to flow inside the electromagnet  350 . 
     Since an inner circumferential surface of the electromagnet  350  comes into contact with or is located to be adjacent to an outer circumferential surface of the gas induction pipe  434 , a distance between the electromagnet  350  and the plasma gas may be reduced. Accordingly, the electromagnet  350  may more efficiently focus the plasma gas by increasing a magnetic force toward the plasma gas. 
     Hereinafter, an EUV generation device according to another example embodiment of the inventive concepts will be described. 
       FIG. 4  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
     Referring to  FIG. 4 , an EUV generation device  500  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , the plasma generation module  130 , the RF power supply module  240 , and a condensing module  560 . 
     The condensing module  560  may include a laser incident hole  561  and an EUV exit hole  562 . Also, the condensing module  560  may further include a reflecting mirror  563 . Meanwhile, the condensing module  560  may further include a filter (not shown) which filters focused EUV rays and an optical device (not shown) for changing a path of EUV rays. Since the condensing module  560  focuses and emits EUV rays generated by plasma, it is possible to increase efficiency of supplying EUV rays. 
     The condensing module  560  may be formed to have a semi-elliptical sphere shape formed by cutting an elliptical sphere along a cross section  560   a  perpendicular to a central axis. Here, the central axis may be an axis which connects a first focal point f 1  to a second focal point f 2  of the elliptical sphere. Also, the first focal point f 1  may be a focal point located on one side of an ellipse formed when the elliptical sphere, which forms the condensing module  560 , is cut in a major axis direction. The second focal point f 2  may be a focal point located on the other side of the ellipse. The semi-elliptical sphere may include the first focal point f 1  located on one side and the virtual second focal point f 2  located on the other side. Also, the cross section may be a surface located at an intermediate position of the central axis or a position spaced apart from the intermediate position. Also, the condensing module  560  may be formed as an elliptical mirror or an elliptical reflecting mirror. The condensing module  560  may be formed of a transparent material. For example, the condensing module  560  may be formed of a quartz material. Also, the condensing module  560  may include an Mo—Si multilayer film formed on an inner reflecting surface to efficiently reflect EUV rays. Here, the Mo—Si multilayer film may be a film formed by alternately stacking an Mo layer and an SiC layer. 
     The laser incident hole  561  may be formed at a center of an inner circumferential surface of the semi-elliptical sphere. That is, the laser incident hole  561  may be formed at a point at which a line, which connects the center of the cross section to the first focal point f 1  of the ellipse, meets the inner circumferential surface of the semi-elliptical sphere. The laser incident hole  561  may be formed to have an adequate diameter necessary to allow a laser to pass therethrough. The laser incident hole  561  may be formed as an aperture formed in a general reflecting mirror. The EUV exit hole  562  may be formed on a side opposite to the laser incident hole  561 . The EUV exit hole  562  may be formed at a position at which the semi-elliptical sphere is opened due to the cross section. The EUV exit hole  562  may output generated EUV rays to the outside. 
     The condensing module  560  may be combined such that the laser incident hole  561  communicates with the laser path pipe  131  or the gas focusing pipe  133 . The laser incident hole  561  may be directly connected to the laser path pipe  131  or the gas focusing pipe  133 . The laser incident hole  561  allows lasers to be emitted toward an inside of the condensing module  560  through the laser path pipe  131 . The condensing module  560  may include the laser focal area “a” thereinside. In the condensing module  560 , an area including the first focal point f 1  may be formed as the laser focal area “a.” The laser incident hole  561  allows lasers to be emitted toward the laser focal area a located inside the condensing module  560 . Also, the laser incident hole  561  may allow an ionized plasma gas to flow into the condensing module  560 . 
     The plasma gas and lasers may form plasma in the laser focal area “a” of the condensing module  560  and generate EUV rays. The EUV rays generated using the plasma may be emitted in all directions. The condensing module  560  may condense the EUV rays emitted in a variety of directions and emit the condensed EUV rays in a direction opposite to the laser focal area “a”. Here, the EUV rays emitted by the condensing module  560  may pass through a reflection focal point located on a side of the central axis of the ellipse opposite to the laser focal area “a.” Here, the reflection focal point may be the second focal point f 2  of the ellipse. The EUV rays condensed by the condensing module  560  may pass through the reflection focal point and may be emitted in an opposite direction. 
     The reflecting mirror  563  may be installed at a position adjacent to the reflection focal point and may emit EUV rays in a particular direction. The reflecting mirror  563  may allow EUV rays to exit downward. Here, the exit window  113  may be located on a bottom surface of the housing body  111 . As the reflecting mirror  563 , a general reflecting mirror used for reflecting and condensing EUV rays may be used. Also, the reflecting mirror  563  may be formed as a shape capable of efficiently reflecting and condensing EUV rays. The reflecting mirror  563  may be formed as an elliptical mirror or an elliptical reflecting mirror. Also, the reflecting mirror  563  may include an Mo—Si multilayer film formed on an inner reflecting surface to efficiently reflect EUV rays. 
     Hereinafter, an EUV generation device according to another example embodiment of the inventive concepts will be described. 
       FIG. 5  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concept. 
     Referring to  FIG. 5 , an EUV generation device  600  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , the plasma generation module  130 , the RF power supply module  240 , and a condensing module  660 . 
     The condensing module  660  may include a laser incident hole  661  and the EUV exit hole  562 . Also, the condensing module  660  may further include the reflecting mirror  563 . Also, the condensing module  660  may further include a laser exit hole  664 . 
     The condensing module  660  may be formed to have a semi-elliptical sphere shape formed by cutting an elliptical sphere along a cross section  660   a  perpendicular to a central axis thereof. The semi-elliptical sphere may include a first focal point f 1  located on one side and a virtual second focal point f 2  located on the other side. The condensing module  660 , like the condensing module  560  according to the example embodiment shown in  FIG. 4 , may be formed of sapphire and may include an Mo—Si multilayer film on a reflecting surface. 
     The laser incident hole  661  may be formed at a point at which a line, which is parallel to the cross section and passes through the first focal point f 1 , meets an inner circumferential surface of the elliptical sphere. That is, the laser incident hole  661  may be formed at a position perpendicular to a central axis of the semi-elliptical sphere. The laser incident hole  661  may be formed to have an adequate diameter necessary for allowing a laser to pass therethrough. The EUV exit hole  562  may be formed at a position which meets the laser incident hole  551  at a right angle. That is, the EUV exit hole  562  may be formed at a position at which the semi-elliptical sphere is opened by the cross section. The EUV exit hole  562  may output generated EUV rays to the outside. 
     The condensing module  660  may be combined such that the laser incident hole  661  communicates with the laser path pipe  131  or the gas focusing pipe  133 . The laser incident hole  661  may be directly connected to the laser path pipe  131  or the gas focusing pipe  133 . The laser incident hole  661  allows lasers to be emitted toward an inside of the condensing module  660  through the laser path pipe  131 . The laser incident hole  661  may allow an ionized plasma gas to flow into the condensing module  660 . 
     The condensing module  660  may receive lasers which are incident in a horizontal direction and emit EUV rays in a downward direction. Accordingly, in the condensing module  660 , an incident direction of lasers and an exit direction of EUV rays may meet at a right angle. 
     The reflecting mirror  563  may reflect and emit EUV rays toward the exit window  113 . The reflecting mirror  563  may allow EUV rays to exit in a horizontal direction. Here, the exit window  113  may be located on a side surface of the housing body  111 . 
     The laser exit hole  664  may allow lasers which pass through the laser focal area a to exit from the condensing module  660 . A laser dump (not shown) is installed outside the laser exit hole  664  so as to convert energy of lasers which exit therefrom into heat and dissipate the heat. 
       FIG. 6  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
     Referring to  FIG. 6 , an EUV generation device  700  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , the plasma generation module  130 , the RF power supply module  240 , an electromagnet  750 , and the condensing module  560 . 
     The electromagnet  750  may be formed to have an annular shape in which one side and the other side have the same inner diameters. The electromagnet  750  may be formed to have an inner diameter greater than an outer diameter of the cross section of the condensing module  560 . The electromagnet  750  may be located outside the condensing module  560  to surround an area including the laser focal area a. The electromagnet  750  may have an adequate length for focusing a plasma gas in the laser focal area “a.” For example, the electromagnet  750  may be located such that one side thereof comes into contact with or partially overlaps the other side of the laser path pipe  131  or the gas focusing pipe  133 . Also, the other side of the electromagnet  750  may be located on the other side rather than the laser focal area “a” of the condensing module  560 . Accordingly, the electromagnet  750  may focus a plasma gas, which flows into the condensing module  560  through the laser path pipe  131  or the gas focusing pipe  133 , in the laser focal area “a.” 
       FIG. 7  is a configuration diagram of an EUV generation device according to another example embodiment of the inventive concepts. 
     Referring to  FIG. 7 , an EUV generation device  800  according to another example embodiment of the inventive concepts may include the housing module  110 , the laser source  120 , the plasma generation module  130 , the RF power supply module  240 , an electromagnet  850 , and the condensing module  560 . 
     The electromagnet  850  may be formed to have an annular shape and may have an inner circumferential surface having a shape corresponding to that of an outer circumferential surface of the condensing module  560 . That is, the electromagnet  850  may be formed to have a shape in which an inner diameter increases from one side toward the other side. The electromagnet  850  may have an adequate length for focusing a plasma gas in the laser focal area “a.” For example, the electromagnet  850  may be located such that one side thereof comes into contact with or partially overlaps the other side of the laser path pipe  131  or the gas focusing pipe  133 . Also, the other side of the electromagnet  850  may be located on the other side rather than the laser focal area “a” of the condensing module  560 . Accordingly, since the electromagnet  850  is installed to be adjacent to the condensing module  560 , it is possible to efficiently focus a plasma gas which flows into the condensing module  560 . 
     According to the example embodiments of the inventive concepts, an EUV generation device which improves output intensity and emission efficiency of EUV rays can be realized. 
     According to one or more example embodiments, while not illustrated, the EUV generation devices  100  to  800  may further include a controller (not illustrated) configured to control the laser source, vacuum pump, gas source, RF power source and/or electromagnet such that the EUV generation devices  100  to  800  preionized the plasma gas supplied thereto and generates plasma by emitting a laser to the plasma gas in the preionized state such that the EUV generation devices  100 - 800  may increase output intensity and emission efficiency of EUV rays. 
     In some example embodiments, the controller implemented using hardware, a combination of hardware and software, or a non-transitory storage medium storing software that is executable to perform the functions of the same. 
     Hardware may be implemented using processing circuity such as, but not limited to, one or more processors, one or more Central Processing Units (CPUs), one or more controllers, one or more arithmetic logic units (ALUs), one or more digital signal processors (DSPs), one or more microcomputers, one or more field programmable gate arrays (FPGAs), one or more System-on-Chips (SoCs), one or more programmable logic units (PLUs), one or more microprocessors, one or more Application Specific Integrated Circuits (ASICs), or any other device or devices capable of responding to and executing instructions in a defined manner. 
     Software may include a computer program, program code, instructions, or some combination thereof, for independently or collectively instructing or configuring a hardware device to operate as desired. The computer program and/or program code may include program or computer-readable instructions, software components, software modules, data files, data structures, etc., capable of being implemented by one or more hardware devices, such as one or more of the hardware devices mentioned above. Examples of program code include both machine code produced by a compiler and higher level program code that is executed using an interpreter. 
     For example, when a hardware device is a computer processing device (e.g., one or more processors, CPUs, controllers, ALUs, DSPs, microcomputers, microprocessors, etc.), the computer processing device may be configured to carry out program code by performing arithmetical, logical, and input/output operations, according to the program code. Once the program code is loaded into a computer processing device, the computer processing device may be programmed to perform the program code, thereby transforming the computer processing device into a special purpose computer processing device. In a more specific example, when the program code is loaded into a processor, the processor becomes programmed to perform the program code and operations corresponding thereto, thereby transforming the processor into a special purpose processor. In another example, the hardware device may be an integrated circuit customized into special purpose processing circuitry (e.g., an ASIC). 
     A hardware device, such as a computer processing device, may run an operating system (OS) and one or more software applications that run on the OS. The computer processing device also may access, store, manipulate, process, and create data in response to execution of the software. For simplicity, one or more example embodiments may be illustrated as one computer processing device; however, one skilled in the art will appreciate that a hardware device may include multiple processing elements and multiple types of processing elements. For example, a hardware device may include multiple processors or a processor and a controller. In addition, other processing configurations are possible, such as parallel processors. 
     Storage media may also include one or more storage devices at units and/or devices according to one or more example embodiments. The one or more storage devices may be tangible or non-transitory computer-readable storage media, such as random access memory (RAM), read only memory (ROM), a permanent mass storage device (such as a disk drive), and/or any other like data storage mechanism capable of storing and recording data. The one or more storage devices may be configured to store computer programs, program code, instructions, or some combination thereof, for one or more operating systems and/or for implementing the example embodiments described herein. The computer programs, program code, instructions, or some combination thereof, may also be loaded from a separate computer readable storage medium into the one or more storage devices and/or one or more computer processing devices using a drive mechanism. Such separate computer readable storage medium may include a Universal Serial Bus (USB) flash drive, a memory stick, a Blu-ray/DVD/CD-ROM drive, a memory card, and/or other like computer readable storage media. The computer programs, program code, instructions, or some combination thereof, may be loaded into the one or more storage devices and/or the one or more computer processing devices from a remote data storage device via a network interface, rather than via a computer readable storage medium. Additionally, the computer programs, program code, instructions, or some combination thereof, may be loaded into the one or more storage devices and/or the one or more processors from a remote computing system that is configured to transfer and/or distribute the computer programs, program code, instructions, or some combination thereof, over a network. The remote computing system may transfer and/or distribute the computer programs, program code, instructions, or some combination thereof, via a wired interface, an air interface, and/or any other like medium. 
     The one or more hardware devices, the storage media, the computer programs, program code, instructions, or some combination thereof, may be specially designed and constructed for the purposes of the example embodiments, or they may be known devices that are altered and/or modified for the purposes of example embodiments. 
     While example embodiments of the inventive concepts have been described with reference to the accompanying drawings, it should be understood by those skilled in the art that various modifications may be made without departing from the scope of the inventive concepts. Therefore, the above-described example embodiments should be considered in a descriptive sense only and not for purposes of limitation.