Patent Publication Number: US-2012024232-A1

Title: Evaporation source for organic material and vapor depositing apparatus including the same

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on 29 Jul. 2010 and there duly assigned Serial No. 10-2010-0073530. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention described technology relates generally to an organic material evaporation source and a vapor depositing apparatus including the same. More particularly, the present invention described technology relates generally to an organic material evaporation source that can deposit an organic material to a large-sized substrate, and a depositing apparatus including the same. 
     2. Description of the Related Art 
     An organic light emitting diode (OLED) display is a flat display device that has a self emissive characteristic and does not require a separate light source so that it can be made light weight and thin. Particularly, the OLED display exhibits quality characteristics such as low power consumption, high luminance, high response speed, and as such, the OLED display receives much attention as a next-generation display device. 
     In general, the OLED display includes an organic light emitting element that includes an anode, an organic emission layer, and a cathode. Holes and electrons are injected from the anode and the cathode, respectively, to form excitons, and the excitons make a transition to a ground state, thereby causing the organic light emitting diode to emit light. 
     The organic emission layer is formed with an organic thin film, and the organic thin film is formed on a substrate of the OLED display, using a physical vapor deposition (PVD) method like a vacuum evaporation method and a wet coating method. As a general method to form a metal electrode and an organic thin film, the vacuum evaporation method is used to form an organic thin film in a vapor deposition apparatus that includes an organic material evaporation source having a crucible by inserting a vapor deposition material in the crucible and depositing the vapor deposition material by heating the crucible with a predetermined temperature. 
     In order to deposit an organic thin film on a large-sized substrate using the evaporation apparatus, the organic material evaporation source and the crucible provided therein should be made large. As the crucible is increased in size, internal temperature deviation of the crucible may be increased, and the organic material, which is a vapor deposition material, may be differentially exhausted according to a location of the crucible so that efficiency of the organic thin film may deteriorate. In addition, when a difference between the temperature applied to the organic material and a sublimation temperature is greater than a predetermined temperature, the organic material may be degenerated, and the temperature deviation in the crucible makes control of the temperature applied to the organic material difficult, and accordingly, the degeneration of the organic material cannot be effectively suppressed. 
     In addition, a method for increasing efficiency of the organic material even though the temperature deviation occurs by forming the internal structure of the crucible complicated has been suggested, but the organic material is evaporated or sublimated when the internal structure of the crucible is complicated so that the internal pressure of the crucible is increased and the evaporation temperature or the sublimation temperature of the organic material is increased, and accordingly a temperature-sensitive organic material may be degenerated. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The described technology has been made in an effort to provide an organic material evaporation source that can reduce internal temperature deviation while forming a large-sized crucible and prevent generation of foreign particles during a vapor deposition process. 
     Further, the present invention is provided to suppress deformation of internal parts of the organic material evaporation source due to thermal expansion differences therebetween. 
     Another purpose of the present invention is to provide an organic material vapor deposition apparatus that can form an organic thin film with a uniform thickness on a large-sized substrate. 
     An organic material evaporation source according to an exemplary embodiment of the present invention includes a crucible including a body and nozzle connected to an opening formed at one side of the body, a heater disposed adjacent to the crucible, and a housing receiving the crucible and the heater. The crucible is formed of a metal coated with steel use stainless (SUS). 
     The metal may be copper or aluminum. 
     The thickness of the SUS formed on the metal may be about 0.05 mm to about 0.5 mm. 
     The organic metal evaporation source according to the exemplary embodiment of the present invention may further include a heater frame disposed between the crucible and the housing and a support supporting the crucible and the heater frame. The heater frame supports the heater. The support may include a first support that connects the crucible to the heater frame and a second support that connects the heater frame to the housing. 
     The first support may include a first center support connected to a center portion of the crucible and the heater frame and a first edge support connected to an edge of the crucible and the heater frame. The first center support may be formed to be fixed to the crucible and the heater frame, and the first edge support may be formed to be movable between the crucible and the heater frame. 
     The second support may include a second center support connected to a center portion of the heater frame and the housing and a second edge support connected to an edge of the heater frame and the housing. The second center support may be formed to be fixed to the heater frame and the housing, and the second edge support may be formed to be movable between the heater frame and the housing. 
     A first groove may be formed in at least one of the crucible and the heater frame, connected with the first center support and a first end of the first center support may be inserted to the first groove. Further, a second groove may be formed in at least one of the heater frame and the housing, connected with the second center support and a first end of the second center support may be inserted to the second groove. 
     The first edge support and the second edge support may have a sphere or cylinder shape. 
     The support may include ceramic or glass. 
     The organic material evaporation source according to the exemplary embodiment of the present invention may further include an insulating plate formed between the heater frame and the housing. 
     The housing may include a cooling member. 
     The nozzles may be arranged with a constant distance from each other along one side of the crucible. 
     An organic metal vapor deposition apparatus according to another exemplary embodiment of the present invention includes a substrate fixing member for fixing a substrate, an organic material evaporation source for depositing an organic material on the substrate, an evaporation source support member for supporting the organic material evaporation source, and a chamber receiving the substrate, the substrate fixing member, the organic material evaporation source, and the evaporation source support member. The organic material evaporation source includes a crucible including a body and nozzles connected to an opening formed at one side of the body, a heater disposed adjacent to the crucible, and a housing receiving the crucible and the heater, and the crucible is formed of a metal coated with steel use stainless (SUS). 
     The metal may be copper or aluminum. 
     The nozzles may be arranged with a constant distance from each other along a first direction at one side of the organic material evaporation source, facing the substrate of the crucible. 
     The organic material vapor deposition apparatus according to the other exemplary embodiment may further include a blocking plate disposed between the substrate and the organic material evaporation source. 
     The blocking plate may be extended along the first direction, and is disposed adjacent to one side of the organic material evaporation source when viewed from the substrate to the organic material evaporation source. A width of the blocking plate, measured along a second direction that is perpendicular to the first direction may have a portion corresponding to the center of the organic material evaporation source formed to be greater than a portion corresponding to an edge of the organic material evaporation source. 
     The blocking plate may be formed as a pair that are symmetric with reference to the organic material evaporation source. 
     The evaporation support member may include a guide for transferring the organic material evaporation source along a second direction that crosses the first direction and the blocking plate is transferred with a speed that is the same as the transfer speed of the organic material evaporation source. 
     According to the exemplary embodiments of the present invention, internal temperature deviation and internal pressure deviation that may occur during vapor deposition of the organic material on the large-sized substrate can be suppressed, thereby suppressing degeneration of the organic material, and generation of foreign particles during the vapor deposition process can be suppressed. 
     In addition, deformation and scratch due to thermal expansion difference between each part of the organic material evaporation source can be suppressed. 
     Further, the organic material can be uniformly exhausted and an organic thin film can be formed on the large-sized substrate with a uniform thickness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
         FIG. 1  is a perspective view of an organic material evaporation source according to an exemplary present invention. 
         FIG. 2  is a side cross-sectional view of the organic material evaporation source according to the exemplary embodiment of the present invention, taken along the line II-II of  FIG. 1 . 
         FIG. 3  is a front view of the organic material evaporation source according to the exemplary embodiment of the present invention. 
         FIGS. 4A to 4C  are cross-sectional views of a center support of the organic material evaporation source according to the exemplary embodiment and exemplary variations of the present invention. 
         FIGS. 5A and 5B  are cross-sectional views of an edge support of the organic material evaporation source according to the exemplary embodiment and exemplary variations of the present invention. 
         FIG. 6  is a cross-sectional view of a crucible of an organic material evaporation source according to the exemplary embodiment of the present invention, taken along the line VI-VI of  FIG. 3 . 
         FIG. 7  is a schematic cross-sectional view of an organic material vapor deposition apparatus according to an exemplary embodiment of the present invention. 
         FIG. 8  is a schematic front view of an evaporation source of the organic material vapor deposition apparatus according to the exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. 
     The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. The size and thickness of each component shown in the drawings are arbitrarily shown for understanding and ease of description, but the present invention is not limited thereto. 
       FIG. 1  is a perspective view of an organic material evaporation source according to an exemplary embodiment of the present invention,  FIG. 2  is a side cross-sectional view of the organic material evaporation source according to the exemplary embodiment of the present invention, taken along the line II-II of  FIG. 1 , and  FIG. 3  is a front view of the organic material evaporation source according to the exemplary embodiment of the present invention. 
     Referring to  FIGS. 1 to 3 , an organic material evaporation source  100  according to the present exemplary embodiment includes a crucible  10 , a heater  20 , and a housing  50  that receives the crucible  10  and the heater  20 . The organic material evaporation source  100  may further include a heater frame  30  that arranges the heater  20  to be adjacent to the crucible  10  and fixes the same, and an insulating plate  40  disposed between the heater frame  30  and the housing  50 . In  FIG. 1 , one side of the housing  50  and a front side of the insulating plate  40  are omitted, and in  FIG. 3 , the front side of the insulating plate  40  is omitted for better understanding and ease of description. 
     According to the present exemplary embodiment, the crucible  10  includes a body  12  and a barrier rib  13  formed in the body  12 . An organic material  15  is stored in one space partitioned by the barrier rib  13  in the body  12  of the crucible  10 , and the organic material  15  is evaporated or sublimated by being heated by the heater  20  disposed the outside of the crucible  10  and then emitted to the outside. In the body  12  of the crucible  10 , an opening is formed at an opposite side of the space where the organic material  15  is stored in the crucible  10 . In addition, the crucible  10  includes a nozzle  11  formed at a side of the body  12  and communicating with the opening formed at one side of the body  12 , and the evaporated or sublimated organic material is sprayed to the substrate through the nozzle  11  such that an organic thin film is formed. 
     The heater  20  is disposed at the outside of the crucible  10 . In the present exemplary embodiment, the heater  20  may be provided at upper and lower portions of the crucible  10  with reference to the z-axis, but it may be formed at only one side or formed to surround the entire sides of the crucible  10 , excluding the side where the nozzle  11  is formed. That is, the arrangement and the shape of the heater  20  may be variously modified as long as the heater  20  can heat the organic material  15  received in the crucible  10  to the evaporation temperature or the sublimation temperature. 
     The crucible  10  is formed with a material having excellent thermal conductivity in order to effectively transfer the heat generated from the heater  20  to the organic material  15  and minimize the temperature deviation in the crucible  10 . In the present exemplary embodiment, a metal such as cooper or aluminum may be used as the material having excellent thermal conductivity. 
     However, the strength of the material having excellent thermal conductivity is not strong enough so that it may be easily broken. In addition, when the material is heated to a temperature that is as high as about 400° C. to about 600° C. under high vacuum state, metal atoms such as cooper atoms or aluminum atoms may be partially sublimated so that the substrate where the organic material is deposited may be contaminated. 
     Stainless steel has high strength at high temperature with high vacuum condition, and thus when the crucible  10  is formed with stainless steel, the crucible  10  is not easily broken during the vapor deposition process and sublimation does not occur at high temperature so that foreign particles can be prevented from being generated. However, the stainless steel has low thermal conductivity so that the heat generated from the heater  20  cannot be effectively transferred to the organic material  15 , and an internal temperature deviation of the crucible  10  may be high. 
     Accordingly, in the present exemplary embodiment, the crucible  10  is formed by coating steel use stainless (SUS) to a metal such as copper or aluminum. Particularly, since copper and partial aluminum have a thermal expansion coefficient that is almost the same as that of SUS, even though the metal is coated with SUS, no breakage may occur due to the thermal expansion amount difference at a contact side of the metal and the SUS when the temperature of the crucible  10  is increased. 
     The coating of the SUS may be performed through brazing in the vacuum state, and the metal can completely adhere to the SUS through the brazing. The brazing is a method to deposit material by disposing an alloy having a low melting point between the materials and heating to a temperature at which the alloy can be melt, and in the present exemplary embodiment, a metal such as cooper or aluminum adheres to the SUS using high-frequency heat under the vacuum state. 
     The SUS coated to the metal and the like has a thickness of about 0.05 mm to about 0.5 mm. In order to assure the solidity of the crucible  10  and suppress generation of the foreign particles, the SUS is preferably coated with a thickness of greater than about 0.05 mm, and, in consideration of the lower thermal conductivity of the SUS, the thickness of the crucible  10  is preferably less than about 0.5 mm to increase the thermal conductivity efficiency through the crucible  10  and suppress the internal temperature deviation of the crucible  10 . 
     As described, the crucible  10  is formed with the metal coated with the SUS so that the terminal conductivity of the crucible  10  can be increased and the internal temperature deviation of the crucible  10  can be suppressed. Accordingly, the organic material  15  can be uniformly exhausted, degeneration of the organic material  15  can be suppressed and simultaneously the generation of the foreign particles during the evaporation process can be suppressed, thereby preventing contamination of the substrate. Further, the solidity of the crucible  10  is assured so that the crucible  10  can be prevented from being broken during the evaporation process. In the present exemplary embodiment, the organic material evaporation source  100  is exemplarily formed as a linear evaporation source, but the present invention is not limited thereto. That is, the shape of the evaporation source applied to the present invention can be variously modified according to the purpose of the present invention. 
     The organic material evaporation source  100  according to the present exemplary embodiment further includes the heater frame  30  for fixing the heater  20 . The heater frame  30  fixes the heater  20  using a heater support  31 , is connected with the crucible  10  through first supports  61   a  and  62   a , and connected with the housing  50  through second supports  61   b  and  62   b . The heater  20  can be fixed to a consistent position and the crucible  10  and the heater  20  can be fixed to a consistent position in the housing by the heater frame  30  and the supports  61  and  62 . Thus, the organic material  15  can be uniformly heated, and the evaporated or sublimated organic material can be deposited to a consistent position of the substrate in the case that the organic material evaporation source  100  is transferred during the vapor deposition process. 
     Meanwhile, during a process that the heat generated from the heater  20  is transferred to the crucible  10 , large thermal energy may be transferred through the supports  61  and  62  due to a high temperature deviation between the crucible  10 , the heater frame  30 , and the housing  50 . As described, when the heat is transferred through the supports  61  and  62 , the temperature deviation of the crucible  10  may occur so that the organic material may be differently exhausted or degenerated. Further, the temperature deviation at a contact points in the upper or lower portion of the supports  61  and  62  is very high so that the supports  61  and  62  may be damaged due to heat and impact. 
     Thus, the supports  61  and  62  according to the present exemplary embodiment are formed with ceramic or glass having very low thermal conductivity. In this case, ceramic having a good void ratio may be used to further decrease the thermal conductivity, or tempered glass having excellent impact resistance or quartz glass having excellent heat insulation and thermal resistance may be used. 
     During the vapor deposition process, the heat transferred from the heater  20  may cause expansion of the crucible  10  and the heater frame  30 . Particularly, the housing  50  is exposed to the outside and thus the heat dissipates therefrom, the heat transfer to the housing  50  may be blocked by the insulating plate  40 , or the housing  50  may be cooled by a cooling member, the thermal expansion amount of the crucible  10  and the heater frame  30  is comparatively higher than that of the housing  50 . As described, when the thermal expansion amount of the crucible  10  and the heater frame  30  is different from that of the heater frame  30  and the housing  50 , a large thermal stress is generated at a portion where each part contacts the supports  61  and  62 , and accordingly, each part may be permanently deformed. 
     Thus, in the present exemplary embodiment, the deformation due to the difference of the thermal expansion amount can be suppressed by improving the shape of the center support  61  at the center of the crucible  10 , the heater frame  30 , and the housing  50  and the edge support  62  at the edge thereof. 
       FIGS. 4A to 4C  are schematic cross-sectional views of second center supports of the organic material evaporation source according to the exemplary embodiment of the present invention and exemplary variations thereof, and a detailed shape of the center support  61  will be described with reference to the drawings. The shape of first center support  61   a  is the same as that of the second center support  61   b , and therefore, the shape of the center support  61  will be described, focusing the second center support  61   b.    
     Referring to  FIG. 4A , a groove (a second groove)  50   a  is formed at the housing  50  that contacts the second center support  61   b  such that a first end of the second center support  61   b  is inserted to the groove  50   a  of the housing  50  and a second end thereof contacts the heater frame  30 . As described, the second center support  61   b  is disposed between the heater frame  30  and the housing  50 , and movement to the horizontal direction in  FIG. 4A  is suppressed by inserting the first end of the second center support  61   b  to the groove  50   a  formed in the housing  50 . Thus, the second center support  61   b  and the center of the heater frame  30  and the housing  50 , supported by the second center support  61   b  cannot be changed, and accordingly, a constant distance can be maintained between the heater frame  30  and the housing  50 . 
     Meanwhile, in the present exemplary embodiment, a cross-section of the first end of the second center support  61   b , inserted to the groove  50   a  formed in the housing  50  has a rectangular shape. However, the cross-sectional shape of the first end of the second center support  61   b  can be variously modified. 
     Referring to  FIG. 4B , a second center support  61   b ′ according to an exemplary variation of the present invention is disposed between a heater frame  30  and a housing  50 ′, and a first end of the second center support  61   b ′ is inserted to a groove  50   a ′ formed in the housing  50 ′. In the present exemplary variation, a cross-sectional shape of the first end of the second center support  61   b ′ has an edge that is not rectangular but round so that it is formed as a part of a circle or oval. In this case, a cross-sectional of the groove  50   a ′ formed in the housing  50 ′ is formed as a part of a circle or oval according to the shape of the first end of the second center support  61   b′.    
     Referring to  FIG. 4C , a second center support  61   b ″ according to another exemplary variation of the present invention is disposed between a heater frame  30  and a housing  50 ″, and a first end of the second center support  61   b ″ is inserted to a groove  50   a ″ formed in the housing  50 ″. In the present exemplary variation, the edges of the first end of the second center support  61   b ″ has a trapezoid shape having inclination rather than having a rectangular or round shape. In this case, the cross-section of the groove  50   a ″ formed in the housing  50 ″ is formed in a trapezoid shape according to the shape of the first end of the second center support  61   b″.    
     In the exemplary embodiment of the present invention and the exemplary variations, the grooves  50   a ,  50   a ′, and  50   a ″ to which the first ends of the second center supports  61   b ,  61   b ′, and  61   b ″ are inserted are formed in the housings  50 ,  50 ′, and  50 ″, but they may be formed in the heater frames  30 . Alternatively, the grooves may be formed both at the housings  50 ,  50 ′, and  50 ″ and the heater frames  30  and both ends of the second center supports  61   b ,  61   b ′, and  61   b ″ may be inserted thereto. According to the exemplary variations, the centers of the heater frames  30  and the housings  50 ,  50 ′, and  50 ″, supported by the second center supports  61   b ,  61   b ′, and  61   b ″ are not changed, constant distances between the heater frames  30  and the housings  50 ,  50 ′, and  50 ″ can be maintained. 
     In addition, as described above, the first center support  61   a  also may be formed to be the same as the second center supports  61   b ,  61 W, and  61   b ″. That is, the first center support  61   a  is disposed between the crucible  10  and the heater frame  30 , and a groove (a first groove) is formed at least one of the crucible  10  and the heater frame  30  to insert a first end or both ends of the first center support  61   a  thereto such that the crucible  10  and the heater frame  30  can be fixed. Accordingly, the center of the crucible  10  and the heater frame  30  cannot be changed, and a constant distance can be maintained between the crucible  10  and the heater frame  30 . 
     As described, the heat emitted from the heater  20  is uniformly transferred to the crucible  10  so that temperature deviation of the crucible  10  can be suppressed by constantly maintaining the distance between the heater frame  30  and the housings  50 ,  50 ′, and  50 ″ and the distance between the crucible  10  and the heater frame  30 , and the evaporated or sublimated organic material can be sprayed to a constant direction through the nozzle  11  of the crucible  10 . 
       FIGS. 5A and 5B  are schematic cross-sectional views of the second edge supports according to the exemplary embodiment of the present invention and exemplary variations, and a detailed description of the edge support  62  will be described with reference to the drawings. The shape of the first edge support  62   a  is the same as that of the second edge support  62   a , and therefore the shape of the edge support  62  will be described, focusing the second edge support  62   b.    
     Referring to  FIG. 5A , a groove  50   b  is formed in the housing  50  that contacts the second edge support  62   b  according to the present exemplary embodiment, and thus a first end of the second edge support  62   b  is inserted to the groove  50   b  of the housing  50  and a second end of the second edge support  62   b  contacts the heater frame  30 . As described, the second edge support  62   b  is disposed between the heater frame  30  and the housing  50 . 
     Meanwhile, the second edge support  62   b  is formed in a sphere or cylinder shape to function as a ball or roller so that the second edge support  62   b  can horizontally move between the heater frame  30  and the housing  50 . As described, since the second edge support  62   b  can horizontally move between the heater frame  30  and the housing  50 , the thermal stress at a portion where the second edge support  62   b  and the heater frame  30  or the housing  50  can be minimized even though the thermal expansion amount of the heater frame  30  is different from that of the housing  50 . Thus, the permanent deformation of the heater frame  30  and the housing  50  can be suppressed, and scratches on the heater frame  30  or the housing  50  due to the second edge support can be suppressed. 
     In this case, the groove  50   b  formed in the housing that contacts the second edge support  62   b  prevents the second edge support  62   b  from being deviated from a position for support the heater frame  30  and the housing  50  while moving. Meanwhile, in the present exemplary embodiment, the groove  50   b  is exemplarily formed in the housing  50  to prevent the second edge support  62   b  from being deviated from the original position, but the groove may be formed in the heater frame  30  or may be formed at both of the heater frame  30  and the housing  50 . 
     Referring to  FIG. 5B , a second edge support  62   b ′ according to an exemplary variation of the present exemplary embodiment, a second edge support  62   b ′ is fixed with a heater frame  30 ′. In further detail, the second edge support  62   b ′ is formed in a sphere or cylinder shape so that it can move between the heater frame  30 ′ and a housing  50 ″, and the rotation center of the second edge support  62   b ′ is connected to the heater frame  30 ′ and fixed thereto. 
     As described, in the present exemplary variation, the rotation center of the second edge support  62   b ′ is fixed to the heater frame  30 ′ to prevent deviation of the second edge support  62   b ′ from a position for supporting the heater frame  30 ′ and the housing  50 ′ while moving, suppress deformation due to the thermal expansion amount difference between the heater frame  30 ′ and the housing  50 ″, and suppress the heater frame  30 ′ and the housing  50 ″ from being scratched. Meanwhile, in the present exemplary variation, the rotation center of the second edge support  62   b ′ is exemplarily fixed to the heater frame  30 ′, but the rotation center of the second edge support  62   b ′ may be fixed to the housing  50 ″. 
     As described above, the first edge support  62   a  may be formed to be the same as the second edge supports  62   b  and  62   b ′. That is, the first edge support  62   a  is formed in a sphere or cylinder shape and movably arranged between the crucible  10  and the heater frames  30  and  30 ′. A groove is formed at least one of the crucible  10  and the heater frame  30  or the first edge support  62   a  is fixed to at least one of the crucible  10  and the heater frame  30  so that deviation due to movement can be suppressed. 
     Referring back to  FIGS. 1 to 3 , the organic material evaporation source  100  according to the present exemplary embodiment may further include the insulating plate  40  disposed between the heater frame  30  and the housing  50 . As shown in  FIG. 2 , the insulating plate  40  is formed to surround the heater frame  30 , and thus it functions to reflect the heat emitted from the heater  20  and the crucible  10  back to the direction of the crucible  10  and simultaneously prevent emission of the heat to the outside of the organic material evaporation source  100 . Further, the insulating plate  40  functions to prevent the heat emitted from the heater  20  and the crucible  10  during the vapor deposition process from being transferred to the substrate. 
     According to the present exemplary embodiment, the housing  50  may include a cooling member. In further detail, the housing  50  has a double-wall structure divided into an inner wall and an exterior wall, and thus a space for taking in and emitting out a coolant can be formed between the walls. This is because to prevent emission of the heat generated from the heater  20  and the like to the outside, and a space where the coolant can directly flow may be formed in the housing  50  as described above or an additional cooling device may be formed in the outside of the housing  50 . 
       FIG. 6  is a cross-sectional view of the crucible of the organic material evaporation source according to the exemplary embodiment of the present invention of  FIG. 3 , taken along the line VI-VI. Hereinafter, arrangement of the nozzle  11  of the crucible  10  according to the present exemplary embodiment will be described with reference to the drawing. 
     With the above-stated configuration of the organic material evaporation source  100 , the internal temperature deviation of the crucible  10  is minimized and accordingly, the organic material at each position in the crucible  10  can be uniformly exhausted. However, in this case that the nozzles are arranged in one side of the crucible with an inconsistent distance therebetween, vapor pressure of the evaporated or sublimated organic material is low in a portion where the distance between the nozzles is relatively narrow and high in a portion where the distance between the nozzles is relative wide. As described, when the vapor pressure deviation occurs according to the internal location of the crucible the evaporation temperature or sublimation temperature of the organic material is increased in the portion where then vapor temperature is relatively high, and accordingly the organic material may be differentially exhausted or degenerated. 
     Thus, the nozzles  11  of the crucible  10  according to the present exemplary embodiment is formed with a constant distance therebetween along one side of the crucible  10  to be communicated with the opening formed at one side of the body  12  of the crucible  10  to thereby constantly maintain the vapor pressure in the crucible  10 . 
     However, when the nozzles  11  are arranged with the equivalent distance, the film thickness may not be uniform during the process for forming the organic thin film on the substrate. That is, a relatively large amount of organic materials is sprayed to a center portion of the substrate, corresponding to a center portion of the organic material evaporation source  100  so that the organic thin film becomes thick, and organic thin film formed at the edge of the substrate may be relatively thin. 
     In the present exemplary embodiment, in order to compensate the thickness deviation in the organic thin film, a blocking plate is disposed between the substrate and the organic material evaporation source  100  in the vapor deposition apparatus, and this will be described with reference to  FIGS. 7 and 8 . 
       FIG. 7  is a schematic cross-sectional view of a vapor deposition apparatus according to an exemplary embodiment of the present invention. Referring to  FIG. 7 , a vapor deposition apparatus  1000  according to the present exemplary embodiment includes an organic material evaporation source  100 , a chamber  200 , a fixing member  300  to fix a substrate S, and an evaporation source supporting member  400  that supports the organic material evaporation source  100 . 
     The organic material evaporation source  100  stores an organic material, heats the organic material for evaporation and sublimation, and then sprays the evaporated or sublimated organic material on the substrate S. A detailed configuration of the organic material evaporation source  100  is the same as the above description, and thus no further description will be provided. 
     The chamber  200  receives the organic material evaporation source  100 , the substrate S, the substrate fixing member  300 , and the evaporation source supporting member  400  to provide a space for vapor deposition. In order to maintain a vacuum state during the vapor deposition process, a vacuum pump (not shown) may be connected to the chamber  200 . 
     The substrate fixing member  300  fixes the substrate S in the chamber  200 . In the present exemplary embodiment, the substrate S is fixed to the ground along a direction (z-axis direction) that is approximately perpendicular to the ground in order to prevent the substrate S from being sagged, but the present invention is not limited thereto. On a front side of the substrate S fixed to the substrate fixing member  300 , that is, a side that faces the organic material evaporation source  100 , a mask M for determining a pattern of the organic thin film deposited thereon may be provided. 
     The evaporation source supporting member  400  supports the organic material evaporation source  100  in the chamber  200 . The evaporation source supporting member  400  includes a support  402  that substantially supports the organic material evaporation source  100  and a guide  401  that can transfer the organic evaporation source  100  on the support  402 . While being transferred by the guide  401 , the organic material evaporation source  100  deposits the organic material on the substrate S. In the present exemplary embodiment, the substrate S is fixed along a direction (z-axis direction) that is approximately perpendicular to the ground, and therefore the organic material evaporation source  100  is transferred along the direction (z-axis) direction that is approximately perpendicular to the ground. 
     Referring to  FIG. 7 , a blocking plate  500  is disposed between the organic material evaporation source  100  and the substrate S. As described above, nozzles are arranged with an equivalent distance in order to maintain uniform vapor pressure in the crucible of the organic material evaporation source  100  such that the thickness of the deposited organic thin film may be not uniform. In the present invention, the non-uniformity of thickness of the organic thin film is compensated using the blocking plate  500 . 
       FIG. 8  is a schematic front view of the organic material evaporation source, viewed from a location of the substrate in the vapor deposition apparatus according to the exemplary embodiment of the present invention. Referring to  FIG. 8 , the blocking plate  500  is arranged along a direction that is parallel with a direction (y-axis direction) in which the nozzles  11  of the organic material evaporation source  100  are arranged in a line with a constant distance with each other. 
     The blocking plate  500  is provided at upper and lower portions of the organic material evaporation source  100  with reference to the z-axis. In addition, the width of a center portion of each blocking plate  500  corresponding to the center portion of the organic material evaporation source  100  is relatively larger than that of the edge portion thereof to compensate a relatively large amount of organic material from being sprayed to the center portion of the substrate, corresponding to the center portion of the organic material evaporation source  100 . 
     In the present exemplary embodiment, a pair of blocking plates  500  is symmetrically arranged, centering the organic material evaporation source  100 , but the present invention is not limited thereto. Only one blocking plate may be formed along one side of the organic material evaporation source  100 . However, when using only one blocking plate, the width of the center portion of the blocking plate should more increased in order to uniformly compensate the thickness of the organic thin film. 
     As described, in the present exemplary embodiment, the blocking plate  500  is disposed between the organic material evaporation source  100  and the substrate S to maintain a uniform thickness of the organic thin film formed on the substrate S. Meanwhile, a detailed shape of the blocking plate  500  for compensating the thickness of the organic thin film is not limited to the drawing, and may be variously modified to compensate a relatively large amount of organic materials sprayed to the center portion of the substrate S. 
     While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.