Patent Publication Number: US-2018037982-A1

Title: Linear evaporation source and deposition apparatus including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority to and all the benefits accruing under 35 U.S.C. §119 of Korean Patent Application No. 10-2016-0099964, filed on Aug. 5, 2016, with the Korean Intellectual Property Office (“KIPO”), the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     Embodiments of the present inventive concept relate to a linear evaporation source and to a deposition apparatus including the linear evaporation source, and more particularly, to a linear evaporation source including a crucible that includes a molybdenum-lanthanum alloy and to a deposition apparatus including the linear evaporation source. 
     2. Description of the Related Art 
     Examples of methods for forming a thin film on a substrate may include a physical vapor deposition (“PVD”) method, such as vacuum evaporation, ion plating, and sputtering, and a chemical vapor deposition (“CVD”) method using gas reaction. 
     A deposition apparatus for performing vacuum evaporation typically includes an evaporation source that includes a crucible for accommodating an evaporation material, a heater for heating the crucible, and a nozzle through which the evaporation material is released. 
     An example of the evaporation source may include a linear evaporation source having a shape elongated in a direction. The linear evaporation source is suitable for forming a deposition layer on a large-sized substrate. However, since having an elongated shape, the linear evaporation source may be fragile to be easily broken at a high temperature, have a temperature deviation based on position, and exhibit low thermal stability. 
     It is to be understood that this background of the technology section is intended to provide useful background for understanding the technology and as such disclosed herein, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of subject matter disclosed herein. 
     SUMMARY 
     Aspects of embodiments of the present inventive concept are directed to a linear evaporation source having high thermal stability. 
     Further, aspects of embodiments of the present inventive concept are directed to a linear evaporation source that may be used in metal deposition and a deposition apparatus including the linear evaporation source. 
     According to an exemplary embodiment of the present inventive concept, a linear evaporation source includes: a crucible configured to accommodate an evaporation material; a heating unit enclosing the crucible and configured to heat the crucible; and a nozzle unit above the crucible, the nozzle unit including a nozzle plate and at least one nozzle protruding from the nozzle plate. A length of the crucible is about 5 times to about 30 times greater than a width of the crucible. The crucible includes molybdenum (Mo) in an amount of about 95.0 percentage by weight (wt %) to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the crucible. 
     The crucible may include molybdenum (Mo) in an amount of about 99.5 wt % to about 99.9 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.1 wt % to about 0.5 wt %, with respect to the total weight of the crucible. 
     The crucible may have a length ranging from about 50 cm to about 500 cm, a width ranging from about 5 cm to about 30 cm, and a height ranging from about 10 cm to about 60 cm. 
     The crucible may be formed by molding, sintering, and forging a mixture of a molybdenum (Mo) powder in an amount of about 95.0 wt % to about 99.99 wt % and a lanthanum oxide (La 2 O 3 ) powder in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the crucible. 
     The linear evaporation source may further include at least one partition wall along a length direction of the crucible. 
     The crucible may have at least one slit defined in a side wall along the length direction of the crucible, and the partition wall may be detachably inserted into the slit. 
     The partition wall may be spaced apart from a bottom surface of the crucible. 
     The heating unit may be configured to heat the crucible to a temperature ranging from about 1000° C. to about 2000° C. 
     The heating unit may include a heater frame and a heater on the heater frame, and the heater may include a plurality of heating elements along a length direction of the heater frame. 
     The plurality of heating elements may be spaced apart from one another along the length direction of the heater frame. 
     A density of the plurality of heating elements at an upper portion of the heater frame may be higher than a density of the plurality of heating elements at a lower portion of the heater frame. 
     The plurality of heating elements may include an upper heating element at an upper portion of the heater frame and a lower heating element below the upper heating element. 
     The linear evaporation source may further include a radiant heat shielding plate. The radiant heat shielding plate may have an aperture for inserting the at least one nozzle and cover the nozzle unit. 
     The radiant heat shielding plate may include at least one selected from the group consisting of: manganese (Mn), titanium (Ti), ZrO 2 , Al 2 O 3 , TiO 2 , pyrolytic boron nitride (PBN), aluminium nitride (AlN), and steel use stainless (SUS). 
     The linear evaporation source may further include a heat conductive plate between the nozzle plate of the nozzle unit and the radiant heat shielding plate. The heat conductive plate may have a hole corresponding to the at least one nozzle and have thermal conductivity. 
     The linear evaporation source may further include an inner plate between a bottom surface of the crucible and the nozzle unit, the inner plate having a plurality of holes. 
     The linear evaporation source may further include a protection container between the crucible and the hating unit. 
     The protection container may include at least one selcted from the group consisting of: tantalum (Ta), pyrolytic boron nitride (PBN), steel use stainless (SUS), aluminium nitride (AlN), molybdenum (Mo) and a molybdenum-lanthanum (Mo—La) alloy. 
     According to an exemplary embodiment of the present inventive concept, a deposition apparatus includes: a process chamber; a linear evaporation source in the process chamber; and a substrate holder spaced apart from the linear evaporation source. The linear evaporation source includes: a crucible configured to accommodate an evaporation material; a heating unit enclosing the crucible and configured to heat the crucible; and a nozzle unit above the crucible, the nozzle unit including a nozzle plate and at least one nozzle protruding from the nozzle plate. A length of the crucible is about 5 times to about 30 times greater than a width of the crucible. The crucible includes molybdenum (Mo) in an amount of about 95.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the crucible. 
     The crucible may include molybdenum (Mo) in an amount of about 99.5 wt % to about 99.9 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.1 wt % to about 0.5 wt % with respect to the total weight of the crucible. 
     The foregoing is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and aspects of the present disclosure of invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view illustrating a deposition apparatus according to a first exemplary embodiment; 
         FIG. 2  is an exploded perspective view illustrating a linear evaporation source according to a second exemplary embodiment; 
         FIG. 3  is a perspective view illustrating the linear evaporation source according to the second exemplary embodiment; 
         FIG. 4  is a cross-sectional view taken along line I-I′ of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view taken along line II-IP of  FIG. 3 ; 
         FIG. 6  is a partial perspective view illustrating a state in which a crucible is disposed in a heating unit; 
         FIG. 7A  is a perspective view illustrating a crucible according to a third exemplary embodiment, and  FIG. 7B  is a cross-sectional view along a length direction of the crucible taken along line of  FIG. 7A ; 
         FIG. 8A  a cross-sectional view along a length direction of a crucible according to a fourth exemplary embodiment, and  FIG. 8B  is a cross-sectional view along a width direction of the crucible according to the fourth exemplary embodiment; 
         FIG. 9A  is a plan view illustrating a partition wall according to a fifth exemplary embodiment, and  FIG. 9B  is a cross-sectional view illustrating disposition of the partition wall according to the fifth exemplary embodiment; 
         FIG. 10  is a perspective view illustrating a heating unit according to an exemplary embodiment; 
         FIG. 11  is a cross-sectional view along a length direction of a heating unit according to an alternative exemplary embodiment; 
         FIG. 12  is a cross-sectional view along a length direction of a heating unit according to another alternative exemplary embodiment; 
         FIG. 13  is a cross-sectional view along a length direction of a heating unit according to still another alternative exemplary embodiment; 
         FIG. 14  is a cross-sectional view along a length direction of a heating unit according to yet another alternative exemplary embodiment; and 
         FIG. 15  is an exploded perspective view illustrating a linear evaporation source according to a sixth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings. Although the invention can be modified in various manners and have several embodiments, exemplary embodiments are illustrated in the accompanying drawings and will be mainly described in the specification. However, the scope of the invention is not limited to the exemplary embodiments and should be construed as including all the changes, equivalents, and substitutions included in the spirit and scope of the invention. 
     In the drawings, thicknesses of a plurality of layers and areas are illustrated in an enlarged manner for clarity and ease of description thereof. When a layer, area, or plate is referred to as being “on” another layer, area, or plate, it may be directly on the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being “directly on” another layer, area, or plate, intervening layers, areas, or plates may be absent therebetween. Further when a layer, area, or plate is referred to as being “below” another layer, area, or plate, it may be directly below the other layer, area, or plate, or intervening layers, areas, or plates may be present therebetween. Conversely, when a layer, area, or plate is referred to as being “directly below” another layer, area, or plate, intervening layers, areas, or plates may be absent therebetween. 
     The spatially relative terms “below”, “beneath”, “less”, “above”, “upper”, and the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device shown in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations. 
     Throughout the specification, when an element is referred to as being “connected” to another element, the element is “directly connected” to the other element, or “electrically connected” to the other element with one or more intervening elements interposed therebetween. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that, although the terms “first,” “second,” “third,” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, “a first element” discussed below could be termed “a second element” or “a third element,” and “a second element” and “a third element” can be termed likewise without departing from the teachings herein. 
     Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an ideal or excessively formal sense unless clearly defined in the present specification. 
     Some of the parts which are not associated with the description may not be provided to specifically describe embodiments of the present inventive concept, and like reference numerals refer to like elements throughout the specification. 
     Hereinafter, a first exemplary embodiment will be described with reference to  FIG. 1 . 
       FIG. 1  is a cross-sectional view illustrating a deposition apparatus  101  according to the first exemplary embodiment. 
     Referring to  FIG. 1 , the deposition apparatus  101  according to the first exemplary embodiment includes a process chamber  200 , a linear evaporation source  300  in the process chamber  200 , and a substrate holder  500  opposing the linear evaporation source  300 . 
     The process chamber  200  serves to provide a space for performing a deposition process and control a pressure inside the process chamber  200 . The process chamber  200  is connected to a vacuum pump  600  for exhausting an evaporation material that is not deposited on a substrate  150 . 
     In addition, the process chamber  200  may include an inlet (not illustrated) through which the substrate  150  to be subject to deposition may be drawn in or out. 
     The substrate holder  500  is configured to allow the substrate  150  that is drawn inside the process chamber  200  to be seated thereon, and may include a fastening member for fastening the substrate  150  during a deposition process. The substrate holder  500  may be fixed to the process chamber  200  by a fixing means  511 . 
     In a deposition process, in order for an evaporation material to be deposited on the substrate  150  into a predetermined pattern, a mask M is disposed between the linear evaporation source  300  and the substrate holder  500 . The mask M may be defined with a plurality of slits. The substrate holder  500  may include a mask supporting member  521 . 
     It is illustrated in  FIG. 1  that the linear evaporation source  300  is disposed at a lower portion of the process chamber  200 , the substrate holder  500  is disposed at an upper portion of the process chamber  200 , and the substrate  150  is fastened by the substrate holder  500  to be horizontal with respect to the ground, but the first exemplary embodiment is not limited thereto. 
     For example, the linear evaporation source  300  may be disposed on one side surface of the process chamber  200 , the substrate holder  500  may be disposed on another side surface of the process chamber  200 , and the substrate  150  fastened to the substrate holder  500  may have an angle ranging from about 70 degrees (°) to about 110° with respect to the ground. In such an exemplary embodiment, sagging of the substrate  150  due to gravity may be effectively reduced by the angle with of substrate  150  with respect to the ground. 
     The linear evaporation source  300  accommodates an evaporation material, heats the evaporation material, and sprays the heated evaporation material onto the substrate  150  such that the evaporation material forms a layer on the substrate  150 . The linear evaporation source  300  extends (e.g., is elongated) in a first direction D 1 . Referring to  FIG. 1 , the first direction D 1  corresponds to a transverse direction of the drawing. 
     The deposition apparatus  101  may further include an evaporation source transfer unit  400 . The evaporation source transfer unit  400  serves to transfer the linear evaporation source  300  in the first direction D 1  or in a direction intersecting the first direction D 1 . The evaporation source transfer unit  400  may include a ball screw  440 , a motor  430  turning the ball screw  440 , and a guide  420  for controlling a transfer direction of the linear evaporation source  300 , for example. 
     Hereinafter, a linear evaporation source and configurations of the linear evaporation source will be described in detail. 
     Hereinafter, a second exemplary embodiment will be described with reference to  FIGS. 2, 3, 4, 5, and 6 . 
       FIG. 2  is an exploded perspective view illustrating a linear evaporation source  302  according to the second exemplary embodiment,  FIG. 3  is a perspective view illustrating the linear evaporation source  302  according to the second exemplary embodiment,  FIG. 4  is a cross-sectional view taken along line I-I′ of  FIG. 3 ,  FIG. 5  is a cross-sectional view taken along line II-II′ of  FIG. 3 , and  FIG. 6  is a partial perspective view illustrating a state in which a crucible  320  is disposed in a heating unit  310 . 
     Referring to  FIGS. 2, 3, 4, 5, and 6 , the linear evaporation source  302  according to the second exemplary embodiment includes the heating unit  310 , the crucible  320 , an inner plate  330 , a nozzle unit  340 , a heat conductive plate  350 , and a radiant heat shielding plate  360 . Although not illustrated, the linear evaporation source  302  may further include a temperature sensing unit. 
     The crucible  320  is configured to accommodate an evaporation material, and an upper portion of the crucible  320  is exposed. The evaporation material refers to a material forming a layer by deposition and is also referred to as an evaporation source. 
     The crucible  320  extends (e.g., is elongated) in a first direction D 1 . That is, the crucible  320  has a linear shape. 
     A length of the crucible  320  may be about five times to about thirty times greater than a width thereof. In an exemplary embodiment, the crucible  320  may have a length ranging from about 50 cm to about 500 cm, a width ranging from about 5 cm to about 30 cm, and a height ranging from about 10 cm to about 60 cm. For example, the crucible  320  may have a length ranging from about 50 cm to about 200 cm, a width ranging from about 10 cm to about 20 cm, and a height ranging from about 20 cm to about 30 cm. However, the second exemplary embodiment is not limited thereto, and a size of the crucible  320  may vary as necessary. Referring to  FIG. 6 , the first direction D 1  corresponds to a length direction of the crucible  320 , a second direction D 2  corresponds to a width direction of the crucible  320 , and a direction orthogonal to the first direction D 1  and the second direction D 2 , i.e., an up-and-down direction in the drawing, corresponds to a height direction of the crucible  320 . 
     The linear evaporation source  302  including the crucible  320  having such a linear shape is advantageous over a point evaporation source that has a bowl shape or a boat shape, when forming a deposition layer on a large-sized substrate. 
     In order to deposit a material, e.g., a metal material, which is evaporated at a high temperature of about 1000° C. or more, a crucible having high-temperature stability is needed. Due to an issue of the high-temperature stability, a point evaporation source has been conventionally used for high temperature deposition performed at a high temperature of about 1000° C. or more. 
     The point evaporation source has a relatively small size, and thus has a relatively low temperature deviation within the point evaporation source and has excellent thermal stability. However, there is a limit in a deposition range, i.e., a deposition area, which is covered by a single point evaporation source. Thus, a plurality of point evaporation sources are required to form a deposition layer on a large-sized substrate. However, in such an exemplary embodiment, there is a difficulty in achieving a uniform deposition layer due to a deposition deviation. 
     The crucible  320  according to the second exemplary embodiment includes an alloy of molybdenum (Mo) and lanthanum (La) (or lanthanum oxide (La 2 O 3 )), thus having excellent high-temperature stability, and thus is advantageous when used in high-temperature deposition using a material that is evaporated at a temperature of about 1000° C. or more. In addition, although having a linear shape, the crucible  320  may not be broken or worn down at a high temperature. Accordingly, the crucible  320  according to the second exemplary embodiment may be suitable to the linear evaporation source  302  used at a high temperature. 
     The linear evaporation source  302  according to the second exemplary embodiment that includes such a crucible  320  may be suitable to a deposition process using a metal material and to a process of forming a deposition layer on a large-sized substrate. 
     According to the second exemplary embodiment, the crucible  320  includes an alloy of molybdenum (Mo) and lanthanum (La) (or lanthanum oxide (La 2 O 3 )). In consideration of thermal stability, mechanical characteristics, and molding properties of the crucible  320 , a content of lanthanum (La) or lanthanum oxide (La 2 O 3 ) is adjusted. For example, the crucible  320  may include molybdenum (Mo) in an amount of about 95.0 percentage by weight (wt %) to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the crucible  320 . In a case where a content of lanthanum oxide (La 2 O 3 ) is less than about 0.01 wt % or more than about 5 wt %, thermal stability, mechanical characteristics, and molding properties of the crucible  320  may be degraded. 
     In an exemplary embodiment, the crucible  320  may include molybdenum (Mo) in an amount of about 98.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 2 wt %, with respect to the total weight of the crucible  320 . For example, the crucible  320  may include molybdenum (Mo) in an amount of about 99.5 wt % to about 99.9 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.1 wt % to about 0.5 wt %, with respect to the total weight of the crucible  320 . 
     For example, the crucible  320  may include molybdenum (Mo) in an amount of about 99.5 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.5 wt %. An alloy including molybdenum (Mo) and lanthanum oxide (La 2 O 3 ) may have a structure in which lanthanum oxide (La 2 O 3 ) is positioned in an interstitial site of a BCC crystalline structure of molybdenum (Mo). 
     The crucible  320  may be formed through molding and sintering using a powder mixture of molybdenum (Mo) and lanthanum (La) or a powder mixture of molybdenum (Mo) and lanthanum oxide (La 2 O 3 ). In addition, after sintering, a thermal treatment process or a forging process may further be performed. 
     Sintering may be performed at a temperature ranging from about 2000° C. to about 2500° C. For example, sintering may be performed at a temperature of about 2200° C. 
     Thermal treatment or forging may be performed at a temperature ranging from about 1300° C. to about 1500° C. For example, forging may be performed at a temperature of about 1400° C. Thermal stability of the crucible  320  may be improved through forging or thermal treatment. 
     The linear evaporation source  302  may include at least one partition wall  325  disposed in the crucible  320 . The partition wall  325  serves to partition the evaporation material accommodated in the crucible  320  and prevent the evaporation material from being unnecessarily concentrated on one side. Accordingly, heat applied from the heating unit  310  may be transmitted to the evaporation material uniformly. The partition wall  325  is not invariably necessary and may be omitted. 
     The partition wall  325  may include a passage (refer to  FIGS. 8B and 9B ) through which the evaporation material may move. The evaporation material moves through such a passage, and thus an amount of the evaporation material that is accommodated in each area defined by the partition wall  325  may be uniformly adjusted. 
     The partition wall  325  may include substantially a same material as a material included in the crucible  320 . For example, the partition wall  325  may include molybdenum (Mo) in an amount of about 95.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the partition wall  325 . In consideration of thermal stability, mechanical characteristics, and molding properties of the partition wall  325 , a content of lanthanum (La) or lanthanum oxide (La 2 O 3 ) is adjusted. In a case where a content of lanthanum oxide (La 2 O 3 ) is less than about 0.01 wt % or more than about 5 wt %, thermal stability, mechanical characteristics, and molding properties of the partition wall  325  may be degraded. 
     For example, the partition wall  325  may include molybdenum (Mo) in an amount of about 98.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 2 wt %, with respect to the total weight of the partition wall  325 . 
     The nozzle unit  340  includes a nozzle plate  341  above the exposed upper portion of the crucible  320  and at least one nozzle  342  protruding from the nozzle plate  341 . 
     Referring to  FIGS. 1 and 4 , the nozzle unit  340  includes a plurality of nozzles  342 . The plurality of nozzles  342  may be disposed along the first direction D 1  at equidistant gaps, or may not. For example, referring to  FIGS. 2 and 4 , the plurality of nozzles  342  are disposed along the first direction D 1  at non-equidistant gaps. In order to impart a uniform thickness to a layer that is formed by deposition, gaps among the nozzles  342  may be adjusted. The gap among the nozzles  342  may vary based on the kinds of the evaporation material, a heating temperature of the crucible  320 , a size of the crucible  320 , and a size of a substrate to be subject to deposition. 
     The nozzle  342  has a hole  343  passing through the nozzle plate  341 , and the evaporation material in the crucible  320  is dispersed through the nozzle  342  outwardly of the linear evaporation source  302  and then deposited on the substrate  150  subject to deposition. 
     The heating unit  310  is configured to heat the crucible  320 . The heating unit  310  includes a heater frame  311  and a heater  312  fixed to the heater frame  311 . 
     The heater frame  311  is spaced apart from the crucible  320  to enclose a side surface and a bottom surface, and not an upper surface, of the crucible  320 . A shape of the heater frame  311  is not particularly limited, as long as the heater frame  311  may support the heater  312 . 
     In some embodiments of the present inventive concept, the heater  312  is disposed on an inner wall  311   a  and  311   b  (as shown in an example in  FIG. 10 ) facing the crucible  320 . The heater  312  may include a heating coil, and may heat the side surface and the bottom surface of the crucible  320  to control a temperature of the crucible  320  uniformly. 
     The heating unit  310  may heat the crucible  320  so that the temperature of the crucible  320  becomes about 1000° C. to about 2000° C. 
     The heating unit  310  may include a single heater or may include a plurality of separated heaters. Referring to  FIGS. 4, 5, and 6 , the heater  312  including a plurality of heating elements is disposed on the heater frame  311 . In  FIG. 6 , a direction D 1  corresponds to a length direction of the heater frame  311 . The heater  312  is disposed at least on a side wall of the heater frame  311  along the length direction. 
       FIG. 6  illustrates the heater  312  including a plurality of heating elements disposed along the inner wall of the heater frame  311 . However, the second exemplary embodiment is not limited thereto, and a plurality of separate plate-shaped or circular-shaped heaters may be disposed on the inner wall of the heater frame  311 . In addition, a temperature of each heater  312  may be adjusted, separately. 
     The position and the number of the heaters  312  may vary as necessary. In a case where the crucible  320  is heated to a relatively high temperature, a great number of heaters  312  may be used. In an exemplary embodiment, in a case where the crucible  320  is heated to a high temperature, e. g., about 1500° C. or more, in order to prevent agglomeration of the evaporation material at the nozzle unit  340 , the heaters  312  may be largely disposed adjacent to an upper portion of the crucible  320 . Where necessary, the heaters  312  may be largely disposed adjacent to a lower portion of the crucible  320 . 
     The linear evaporation source  302  may include a temperature sensing unit (not illustrated). The temperature sensing unit, for example, may be fixed to the heater frame  311  to be disposed between the crucible  320  and the heater  312 . 
     The position and the number of the temperature sensing units may vary based on sizes of the crucible  320  and the heater  312 . For example, the temperature sensing unit may measure the temperature of the crucible  320  for each position thereof. Based on the temperature of the crucible  320  for each position which is measured by the temperature sensing unit, the temperature of the heater  312  is controlled such that an overall temperature of the crucible  320  may be uniformly controlled. 
     The radiant heat shielding plate  360  has an aperture  362  for inserting the nozzle  342 , and covers the nozzle unit  340 . 
     The radiant heat shielding plate  360  may be disposed above the heating unit  310  to enclose the crucible  320  and the nozzle unit  340 . The radiant heat shielding plate  360  serves to suppress release of heat generated from the heating unit  310  to inside of the process chamber  200 . Accordingly, heat emitted from the crucible  320  and the heating unit  310 , having a high temperature, may not affect a deposition layer or may not damage a structure inside the chamber. 
     The nozzle  342  is inserted into the aperture  362  of the radiant heat shielding plate  360 . An end portion of the nozzle  342  is exposed by the aperture  362 . The nozzle  342  may protrude from the aperture  362  or may not. For example, referring to  FIG. 4 , the nozzle  342  has substantially a same height as a height of an upper surface of the radiant heat shielding plate  360 , and so does not protrude from the aperture  362 . The nozzle  342  may be disposed to be dented from the upper surface of the radiant heat shielding plate  360 . 
     The radiant heat shielding plate  360  may include a material having a relatively low heat transfer coefficient and relatively low emissivity. For example, the radiant heat shielding plate  360  may include at least one of: manganese (Mn), titanium (Ti), ZrO 2 , Al 2 O 3 , TiO 2 , pyrolytic boron nitride (PBN), aluminum nitride (AlN), and steel use stainless (SUS). 
     The heat conductive plate  350  is disposed between the nozzle plate  341  of the nozzle unit  340  and the radiant heat shielding plate  360 . The heat conductive plate  350  has thermal conductivity, and has a hole  352  corresponding to the nozzle  342 . 
     The nozzle  342  is inserted into the hole  352  of the heat conductive plate  350 . 
     The heat conductive plate  350  may include a heat conductive material. The heat conductive plate  350  may include tantalum (Ta), for example. In an alternative exemplary embodiment, the heat conductive plate  350  may include a metal alloy such as aluminum alloys and molybdenum alloys. 
     The heat conductive plate  350  may be spaced apart from the radiant heat shielding plate  360  or may contact the radiant heat shielding plate  360 . 
     In addition, the heat conductive plate  350  may be adjacent to the nozzle  342  or may contact the nozzle  342 . As heat is transmitted through the heat conductive plate  350 , the nozzles  342  may have a substantially uniform temperature. That is, the heat conductive plate  350  may prevent heat from being concentrated to one of the nozzles  342 , and thus may serve to reduce a temperature deviation among the nozzles  342 . Accordingly, materials evaporated from the crucible  320  are uniformly dispersed within the process chamber  200  through the nozzle  342 . 
     As disposed above the crucible  320 , the heat conductive plate  350  is also referred to as an upper plate. 
     The inner plate  330  is disposed in the crucible  320 . For example, the inner plate  330  is disposed between a bottom surface  322  of the crucible  320  and the nozzle unit  340 , and has a plurality of holes  332 . 
     The inner plate  330  may serve as a filter. For example, the inner plate  330  serves to allow the material evaporated in the crucible  320  to be uniformly dispersed and flow into the nozzle  342 . 
     The inner plate  330  may include substantially a same material as a material included in the crucible  320 . For example, the inner plate  330  may include molybdenum (Mo) in an amount of about 95.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 5 wt %, with respect to the total weight of the inner plate  330 . In consideration of thermal stability, mechanical characteristics, and molding properties of the inner plate  330 , a content of lanthanum (La) or lanthanum oxide (La 2 O 3 ) is adjusted. In a case where a content of lanthanum oxide (La 2 O 3 ) is less than about 0.01 wt % or more than about 5 wt %, thermal stability, mechanical characteristics, and molding properties of the inner plate  330  may be degraded. 
     For example, the inner plate  330  may include molybdenum (Mo) in an amount of about 98.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.01 wt % to about 2 wt %, with respect to the total weight of the inner plate  330 . 
     The inner plate  330  may be disposed at a locking projection formed at the crucible  320 . The crucible  320  may further include a separate holder (not illustrated) for the inner plate  330 . 
     Hereinafter, a third exemplary embodiment will be described with reference to  FIGS. 7A and 7B . 
       FIG. 7A  is a perspective view illustrating a crucible  3203  according to the third exemplary embodiment, and  FIG. 7B  is a cross-sectional view along a length direction of the crucible  3203  taken along line of  FIG. 7A . 
     Referring to  FIG. 7A , the crucible  3203  has at least one slit  323  defined in a side wall  321  along a length direction D 1 . A partition wall  325  may be detachably inserted into the slit  323 . 
     The position and the number of the slits  323  may vary as necessary. The number of the partition walls  325  may also vary as necessary. Accordingly, an inner space of the crucible  3203  may be divided as necessary, using the partition wall  325 . 
     Hereinafter, a fourth exemplary embodiment will be described with reference to  FIGS. 8A and 8B . 
       FIG. 8A  a cross-sectional view along a length direction of a crucible  3204  according to the fourth exemplary embodiment, and  FIG. 8B  is a cross-sectional view along a width direction of the crucible  3204  according to the fourth exemplary embodiment. 
     Referring to  FIGS. 8A and 8B , a partition wall  326  is spaced apart from a bottom surface  322  of the crucible  3204 . Referring to  FIG. 8B , a slit  323  is defined in a side wall  321  of the crucible  3204 , and the slit  323  is defined only at an upper portion of the side wall  321 , and does not extend to the bottom surface  322  of the crucible  3204 . Accordingly, although the partition wall  326  is inserted into the slit  323 , the partition wall  326  may not contact the bottom surface  322  of the crucible  3204  such that a space is secured between the bottom surface  322  of the crucible  3204  and the partition wall  326 . 
     The space between the bottom surface  322  of the crucible  3204  and the partition wall  326  becomes a passage for an evaporation material accommodated in the crucible  3204 . A melted evaporation material may move through the space between the bottom surface  322  of the crucible  3204  and the partition wall  326 . Accordingly, an amount of the evaporation material accommodated in each area defined by the partition wall  326  may become substantially uniform. 
     Hereinafter, a fifth exemplary embodiment will be described with reference to  FIGS. 9A and 9B . 
       FIG. 9A  is a plan view illustrating a partition wall  327  according to the fifth exemplary embodiment, and  FIG. 9B  is a cross-sectional view illustrating a crucible  3205  including the partition wall  327  according to the fifth exemplary embodiment. 
     Referring to  FIG. 9 , the partition wall  327  has an inverted U-like shape. In a case where such a partition wall  327  is provided in the crucible  3205 , a space may be secured between the partition wall  327  and a bottom surface  322  of the crucible  3205 . An evaporation material may readily move through the space between the bottom surface  322  of the crucible  3205  and the partition wall  327 . 
       FIG. 10  is a perspective view illustrating a heating unit  3103  according to an exemplary embodiment. 
     Referring to  FIG. 10 , a heater  312  including a plurality of heating elements  312   a ,  312   b , and  312   c  is disposed on an inner wall  311   a  and  311   b  of a heater frame  311 . The kinds of the heating elements  312   a ,  312   b , and  312   c  are not particularly limited. An example of the heating elements may include a heating coil. Any heating means known in the pertinent art other than the heating coil may be used as the heating elements  312   a ,  312   b , and  312   c.    
     A long side of the heater frame  311  is referred to as a length direction, and a short side of the heater frame  311  is referred to as a width direction. The length direction corresponds to the direction D 1  of  FIG. 6 , and the width direction corresponds to the direction D 2  of  FIG. 6 . In  FIG. 10 , each of the heating elements  312   a ,  312   b , and  312   c  is continuously disposed along an inner wall  311   a  along the length direction and an inner wall  311   b  along the width direction. 
       FIG. 11  is a cross-sectional view along a length direction of a heating unit  410  according to an alternative exemplary embodiment. 
     In the heating unit  410  illustrated in  FIG. 11 , a heater  412  includes a plurality of heating elements  412   a ,  412   b , and  412   c  disposed on an inner wall  311   a  of a heater frame  311  along a length direction. The heating elements  412   a ,  412   b , and  412   c  may use a heating coil. 
     Referring to  FIG. 11 , the heating elements  412   a ,  412   b , and  412   c  are densely disposed at an upper portion of the heater frame  311  that is adjacent to a nozzle unit  340 . That is, a density of the heating elements  412   a ,  412   b , and  412   c  is higher at the upper portion of the heater frame  311  than a density of the heating elements  412   a ,  412   b , and  412   c  at a lower portion of the heater frame  311 . 
     For example, the heater  412  includes three heating elements  412   a ,  412   b , and  412   c , and each of the heating elements  412   a ,  412   b , and  412   c  may have an inverted U-like shape (∩). 
     The heater  412 , illustrated in  FIG. 11 , having such a shape may readily heat the upper portion of the crucible  320 . 
     In addition, the heating unit  410  illustrated in  FIG. 11  includes a temperature sensing unit  415   a  and  415   b . The temperature sensing unit  415   a  and  415   b  measures temperature. Based on the temperature measured by the temperature sensing unit  415   a  and  415   b , a temperature of the heating elements  412   a ,  412   b , and  412   c  may be adjusted. The temperature sensing unit  415   a  and  415   b  includes an upper temperature sensing unit  415   a  adjacent to the heating elements  412   a ,  412   b , and  412   c  and a lower temperature sensing units  415   b  spaced apart from the heating elements  412   a ,  412   b , and  412   c.    
     The upper temperature sensing unit  415   a  may directly measure the temperature of the heating elements  412   a ,  412   b , and  412   c . The lower temperature sensing unit  415   b  may measure a temperature of an area spaced apart from the heating elements  412   a ,  412   b , and  412   c  at a relatively great distance, thus detecting whether a temperature of the heating unit  410  falls below a predetermined temperature. 
       FIG. 12  is a cross-sectional view along a length direction of a heating unit  510  according to another alternative exemplary embodiment. 
     The heating unit  510  illustrated in  FIG. 12  includes a plurality of heating elements  512   a ,  512   b , and  512   c  disposed on an inner wall  311   a  of a heater frame  311  along a length direction. 
     Referring to  FIG. 12 , a heater  512  includes an upper heating element  512   b  at an upper portion of the heater frame  311  that is adjacent to a nozzle unit  340  and two lower heating elements  512   a  and  512   c  below the upper heating element  512   b . In such an exemplary embodiment, each of the heating elements  512   a ,  512   b , and  512   c  has an inverted U-like shape (∩). 
     Referring to  FIG. 12 , the heating elements  512   a ,  512   b , and  512   c  are densely disposed at an upper portion of the heater frame  311 . That is, a density of the heating elements  512   a ,  512   b , and  512   c  is higher at the upper portion of the heater frame  311  than a density of the heating elements  512   a ,  512   b , and  512   c  at a lower portion of the heater frame  311 . The heater  512  having such a shape may readily heat the upper portion of the crucible  320 . 
     In addition, the heating unit  510  illustrated in  FIG. 12  includes a temperature sensing unit  515   a  and  515   b . The temperature sensing unit  515   a  and  515   b  includes an upper temperature sensing unit  515   a  adjacent to the heating elements  512   a ,  512   b , and  512   c  and a lower temperature sensing unit  515   b  spaced apart from the heating elements  512   a ,  512   b , and  512   c.    
       FIG. 13  is a cross-sectional view along a length direction of a heating unit  610  according to still another alternative exemplary embodiment; 
     The heating unit  610  illustrated in  FIG. 13  includes a plurality of heating elements  612   a ,  612   b ,  612   c , and  612   d  disposed on an inner wall  311   a  of a heater frame  311  along a length direction. 
     Referring to  FIG. 13 , a heater  612  includes two upper heating elements  612   b  and  612   c  at an upper portion of the heater frame  311  that is adjacent to a nozzle unit  340  and two lower heating elements  612   a  and  612   d  below respective ones of the two upper heating elements  612   b  and  612   c . In such an exemplary embodiment, each of the heating elements  612   a ,  612   b ,  612   c  and  612   d  has an inverted U-like shape (∩). 
     Referring to  FIG. 13 , the heating elements  612   a ,  612   b ,  612   c  and  612   d  are densely disposed at an upper portion of the heater frame  311  that is adjacent to the nozzle unit  340 . The heater  612  having such a shape may readily heat the upper portion of the crucible  320 . 
     In addition, the heating unit  610  illustrated in  FIG. 13  includes a temperature sensing unit  615   a  and  615   b . The temperature sensing unit  615   a  and  615   b  includes an upper temperature sensing unit  615   a  adjacent to the heating elements  612   a ,  612   b ,  612   c  and  612   d  and a lower temperature sensing unit  615   b  spaced apart from the heating elements  612   a ,  612   b ,  612   c  and  612   d.    
       FIG. 14  is a cross-sectional view along a length direction of a heating unit  710  according to yet another alternative exemplary embodiment. 
     The heating unit  710  illustrated in  FIG. 14  includes a plurality of heating elements  712   a ,  712   b ,  712   c ,  712   d , and  712   e  disposed on an inner wall  311   a  of a heater frame  311  along a length direction. 
     Referring to  FIG. 14 , a heater  712  includes side heating elements  712   a ,  712   b ,  712   d , and  712   e  respectively disposed on left and right sides of the inner wall  311   a  of the heater frame  311  along the length direction, and a central heating element  712   c  disposed among the side heating elements  712   a ,  712   b ,  712   d , and  712   e . The side heating elements  712   a ,  712   b ,  712   d , and  712   e  include two upper heating elements  712   a  and  712   e  at an upper portion of the heater frame  311  that is adjacent to the nozzle unit  340  and two lower heating elements  712   b  and  712   d  below respective ones of the two upper heating elements  712   a  and  712   e . In such an exemplary embodiment, each of the heating elements  712   a ,  712   b ,  712   c ,  712   d , and  712   e  has an inverted U-like shape (∩). 
     Referring to  FIG. 14 , the heating elements  712   a ,  712   b ,  712   c ,  712   d , and  712   e  are densely disposed at an upper portion of the heater frame  311  that is adjacent to the nozzle unit  340 . The heater  712  having such a shape may readily heat the upper portion of the crucible  320 . 
     In addition, the heating unit  710  illustrated in  FIG. 14  includes a temperature sensing unit  715   a  and  715   b . The temperature sensing unit  715   a  and  715   b  includes an upper temperature sensing unit  715   a  adjacent to the heating elements  712   a ,  712   b ,  712   c ,  712   d , and  712   e  and a lower temperature sensing unit  715   b  spaced apart from the heating elements  712   a ,  712   b ,  712   c ,  712   d , and  712   e.    
     Hereinafter, a sixth exemplary embodiment will be described with reference to  FIG. 15 . 
       FIG. 15  is an exploded perspective view illustrating a linear evaporation source  106  according to a sixth exemplary embodiment. 
     As compared to the linear evaporation source  302  according to the second exemplary embodiment, the linear evaporation source  106  according to the sixth exemplary embodiment further includes a protection container  370  between a crucible  320  and a heating unit  310 . Hereinafter, to avoid repetition, descriptions pertaining to configurations described hereinabove will be omitted. 
     The protection container  370  illustrated in  FIG. 15  has a space for accommodating the crucible  320 . The protection container  370  accommodates and protects the crucible  320 , thus allowing the crucible  320  to be heated uniformly. As disposed outside of the crucible  320 , the protection container  370  may also be referred to as an external crucible. 
     The protection container  370  may include substantially a same material as or a different material from a material included in the crucible  320 . The protection container  370  may include tantalum (Ta), pyrolytic boron nitride (PBN), steel use stainless (SUS), aluminium nitride (AlN), molybdenum (Mo), and/or a molybdenum-lanthanum (Mo—La) alloy, for example. 
     For example, the protection container  370  may include molybdenum (Mo) in an amount of about 95.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.001 wt % to about 5 wt %, with respect to the total weight of the protection container  370 . In consideration of thermal stability, mechanical characteristics, and molding properties of the protection container  370 , a content of lanthanum (La) or lanthanum oxide (La 2 O 3 ) is adjusted. In a case where a content of lanthanum oxide (La 2 O 3 ) is less than about 0.01 wt % or more than about 5 wt %, thermal stability, mechanical characteristics, and molding properties of the protection container  370  may be degraded. 
     For example, the protection container  370  may include molybdenum (Mo) in an amount of about 98.0 wt % to about 99.99 wt % and lanthanum oxide (La 2 O 3 ) in an amount of about 0.001 wt % to about 2 wt %, with respect to the total weight of the protection container  370 . 
     In addition, referring to  FIG. 15 , a partition wall is not provided in the crucible  320 . However, the sixth exemplary embodiment is not limited thereto, and the partition wall may be provided in the crucible  320 . 
     As set forth hereinabove, a crucible according to one or more exemplary embodiments has high thermal stability and excellent durability, and thus a process risk whereby the crucible may be broken in a deposition process may be effectively reduced. Further, a linear evaporation source according to one or more exemplary embodiments has high thermal stability and may accommodate a greater amount of evaporation materials, as compared to a conventional point evaporation source. Accordingly, a continuous driving time of a deposition apparatus increases such that a process efficiency is improved and a manufacturing cost may be reduced 
     From the foregoing, it will be appreciated that various embodiments in accordance with the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present teachings. Accordingly, the various embodiments disclosed herein are not intended to be limiting of the true scope and spirit of the present teachings. Various features of the above described and other embodiments can be mixed and matched in any manner, to produce further embodiments consistent with the invention.