Patent Publication Number: US-2015079274-A1

Title: Crucible for vapor deposition, vapor deposition apparatus and vapor deposition method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority based on Japanese Patent Application No. 2012-027451, the disclosure of which is incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a crucible for vapor deposition, a vapor deposition apparatus and a vapor deposition method that allow a vaporized material vaporized from a vapor deposition source to be vapor-deposited on a substrate to be treated. 
     RELATED ART 
     Regarding conventional vapor deposition apparatuses, for example, a substrate to be treated is disposed in a vacuum chamber and a vapor deposition source is disposed at a predetermined distance from this substrate to be treated. Such vapor deposition apparatuses generally emit the vaporized material vaporized from the vapor deposition source toward the substrate to be treated to thereby form a thin film of a predetermined film thickness (e.g., see Patent Literature 1). 
     More specifically, this vapor deposition apparatus includes in its vacuum chamber, a crucible that stores a vapor deposition source and a heat generator to heat this crucible. The vapor deposition apparatus heats the crucible through radiant heat and/or heat conduction from the heat generator and thereby emits the vaporized material from the vapor deposition source. The vapor deposition apparatus causes the vaporized material to be vapor-deposited on the substrate to be treated, and thereby forms a film. 
     As shown above, in the conventional vapor deposition apparatus, the vapor deposition source and the substrate to be treated are spaced apart from each other, but this spacing is preferably minimized to the extent possible from the standpoint of downsizing of the apparatus and effective utilization of the vapor deposition source. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2008-163365 A 
     DISCLOSURE OF THE INVENTION 
     Problems To Be Solved by the Invention 
     From this standpoint, a technique under research and development in recent years is called “proximity vapor deposition.” As shown, for example, in  FIG. 7 , this proximity vapor deposition uses a crucible  105  which includes a storage section  102  that stores a vapor deposition source  101  and a guide passage  104  that guides a vaporized material from the vapor deposition source  101  to a substrate to be treated  103 . In the proximity vapor deposition, since the guide passage  104  is formed in the crucible  105 , it is possible to minimize the distance between the vapor deposition source  101  and the substrate to be treated  103 . 
     Incidentally, in vapor deposition by the vapor deposition apparatus, it is necessary to check the conditions of the vapor deposition (so-called film formation rate). For this reason, a sensor for measuring the thickness of the film formed on the substrate to be treated is conventionally provided in the vacuum chamber. For example, QCM (Quartz Crystal Microbalance) is used as this sensor. This QCM can detect a film formation rate based on a frequency variation in accordance with the amount of deposition of the vaporized material adhered to a crystal resonator disposed at a predetermined position in the vacuum chamber. 
     When the above-described sensor is also used for proximity vapor deposition, even when the sensor is placed in the vacuum chamber, the vaporized material does not stick out of the guide passage  104  in the crucible  105 . For this reason, the vaporized material does not reach this sensor. Therefore, the sensor cannot detect the film formation rate. 
     On the other hand, this sensor may be placed in the guide passage  104 . In this case, since the vaporized material and the crucible itself in the guide passage  104  are hot, there is a problem that the measuring accuracy of the sensor under influences of high temperature may deteriorate extremely. 
     The present invention has been implemented in view of the above-described circumstances, and it is an object of the present invention to provide a crucible for vapor deposition, a vapor deposition apparatus and a vapor deposition method capable of detecting a film formation rate using a sensor in vapor deposition through proximity vapor deposition. 
     Means for Solving Problems 
     A crucible for vapor deposition according to the present invention is intended to solve the above-described problems and includes a storage section that stores a vapor deposition source, a first guide passage that guides a vaporized material emitted from the vapor deposition source toward a substrate to be treated, a wall section for defining the first guide passage, and a second guide passage that diverges from a middle part of the first guide passage, penetrates the wall section and communicates with the outside. 
     Furthermore, the present invention can adopt a configuration in which a protrusion that protrudes outward is provided on an outside surface of the wall section and the second guide passage is formed so as to penetrate the protrusion and communicate with an orifice of the wall section. 
     According to another aspect of the present invention, there is provided a vapor deposition apparatus, which includes any one of the above-described crucibles for vapor deposition, a vacuum chamber that can store the crucible for vapor deposition therein, a vacuum pump connected to the vacuum chamber, a heater for heating the crucible for vapor deposition, and a sensor for measuring the thickness of a film formed by the vaporized material adhering to a substrate to be treated. 
     Furthermore, according to still another aspect of the present invention, there is provided a vapor deposition method for causing a vaporized material emitted from a vapor deposition source to be vapor-deposited on a substrate to be treated by the above-described vapor deposition apparatus, the method including detecting the vaporized material emitted from the second guide passage by the sensor provided in the vacuum chamber, and causing the vaporized material to be vapor-deposited on the substrate to be treated while measuring the thickness of the film formed by the vaporized material adhering to the substrate to be treated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a vapor deposition apparatus illustrating a first embodiment of the present invention. 
         FIG. 2  is a cross-sectional view of a vapor deposition apparatus illustrating a second embodiment of the present invention. 
         FIG. 3  is a cross-sectional view of a vapor deposition apparatus illustrating a third embodiment of the present invention. 
         FIG. 4  is a cross-sectional view of a vapor deposition apparatus illustrating a fourth embodiment of the present invention. 
         FIG. 5  is a cross-sectional view of a vapor deposition apparatus illustrating a fifth embodiment of the present invention. 
         FIG. 6  is a cross-sectional view of a vapor deposition apparatus illustrating a sixth embodiment of the present invention. 
         FIG. 7  is a cross-sectional view of a crucible illustrating an example of proximity vapor deposition. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to  FIG. 1  to  FIG. 6 .  FIG. 1  illustrates a first embodiment of the present invention. A vapor deposition apparatus  1  according to the present embodiment is used to manufacture, for example, an organic EL device or other devices through so-called proximity vapor deposition. The vapor deposition apparatus  1  forms a thin film of a predetermined thickness by causing a vaporized material vaporized from a vapor deposition source  3  to be vapor-deposited on a predetermined substrate to be treated  2 . More specifically, this vapor deposition apparatus  1  is provided with a vacuum chamber (not shown), a vacuum pump (not shown) connected to the vacuum chamber, a vapor deposition source  3 , a crucible for vapor deposition (hereinafter simply referred to as “crucible”)  4  stored in the vacuum chamber, a sensor  5  provided at a position proximate to the crucible  4  to measure a thickness of a thin film formed on the substrate to be treated  2 , and a heater (not shown) that heats the crucible  4 . 
     Hereinafter, a positional relationship between the crucible  4  and the sensor  5  will be particularly described. As shown in  FIG. 1 , the crucible  4  includes a storage section  11  that stores a vapor deposition source  3 , a first guide passage  12  that guides a vaporized material emitted from the vapor deposition source  3  to the substrate to be treated  2 , an emission port  13  provided at one end of the first guide passage  12  to emit the vaporized material, which passes through this first guide passage  12 , toward the substrate to be treated  2  disposed in proximity to the vapor deposition source  3 , and a second guide passage  14  that diverges from a middle part of the first guide passage  12  and communicates with the outside of the crucible  4 . 
     To store the vapor deposition source  3 , the storage section  11  includes a bottom wall section  16  and a side wall section  17  provided perpendicular to this bottom wall section  16 . A storage space for the vaporized material is formed by the storage section  11  being surrounded by these wall sections. When heated by a heater from the outside, the storage section  11  is configured to transmit the heat to the vapor deposition source  3 . 
     The first guide passage  12  is formed of a wall section provided so as to cover the storage section  11 . This wall section includes a first wall section  21  formed integrally and continuously connected with part of the side wall section  17  of the storage section  11 , a second wall section  22  that extends so as to be substantially orthogonal to the first wall section  21 , and a third wall section  23  provided so as to be substantially orthogonal to the second wall section  22  and substantially parallel to the first wall section  21 . Note that the first wall section  21  and the third wall section  23  are connected via a fourth wall section and a fifth wall section having similar configurations, but description thereof is not repeated in the present embodiment. The first guide passage  12  is formed in a space defined by and covered with the first wall section  21  to the fifth wall section described above. 
     According to the above-described configuration, the first guide passage  12  guides the vaporized material emitted from the vapor deposition source  3  upward via the first wall section  21  and also guides the vaporized material in a lateral direction via the second wall section  22 . Furthermore, the first guide passage  12  guides the vaporized material downward via the third wall section  23 . The first guide passage  12  causes the vaporized material to be emitted toward the substrate to be treated  2  via the emission port  13 . The vaporized material emitted from the emission port  13  is deposited on the substrate to be treated  2 . A film is thus formed on the surface of the substrate to be treated  2 . 
     The second guide passage  14  is provided at a middle part of the second wall section  22 . More specifically, the second guide passage  14  is configured of an orifice  31  that penetrates the second wall section  22  and communicates with the outside. An opening of the orifice  31  on an inner surface side of the second wall section  22  constitutes an inlet  32  for the vaporized material. An opening of the orifice  31  on an outer surface side of the second wall section  22  constitutes an outlet  33  for the vaporized material. The diameter or width of this orifice  31  is constant from the inlet  32  to the outlet  33 . The diameter or width of this orifice  31  is preferably smaller than that of the first guide passage  12 . For example, the diameter or width of this orifice  31  is preferably in the order of 1 mm to 3 mm. However, without being limited to this, the diameter or width of this orifice  31  may also be smaller or greater than the above-described value. 
     In the present embodiment, a crystal resonator (QCM) is used for the sensor  5 . This sensor  5  is provided at a position proximate to the crucible  4  in the vacuum chamber. More specifically, the sensor  5  is disposed above the second guide passage  14  formed in the second wall section  22  of the crucible  4 . Moreover, a detection surface  5   a  of the sensor  5  is disposed so as to face the outlet  33  of the second guide passage  14 . 
     According to the vapor deposition apparatus  1  having the above-described configuration and a vapor deposition method using this vapor deposition apparatus  1 , the first guide passage  12  formed in the crucible  4  guides the vaporized material to the substrate to be treated  2 , the second guide passage  14  that diverges from the first guide passage  12  guides the vaporized material to the sensor  5  provided outside the crucible  4 , and it is thereby possible to form a predetermined film on the substrate to be treated  2  and at the same time detect the film formation rate (vapor deposition rate) thereof using the sensor  5 . 
     This second guide passage  14  is formed by simply forming the orifice  31  that penetrates the second wall section  22 , and can thus be manufactured easily due to its simplified structure. 
       FIG. 2  illustrates a second embodiment of the vapor deposition apparatus  1 , the crucible  4  and the vapor deposition method according to the present invention. In the present embodiment, the shape of the orifice  31  as the second guide passage  14  is different from that of the first embodiment. More specifically, in the second guide passage  14  of the aforementioned first embodiment, the orifice  31  is formed such that the diameter or width thereof is constant from the inlet  32  to the outlet  33 , whereas in the present embodiment, the diameter of the inlet  32  is greater than the diameter of the outlet  33 . This allows more vaporized material to be introduced from the inlet  32  of the second guide passage  14  and allows the vaporized material having a higher density to be emitted toward the sensor  5  from the outlet  33  which is formed to be smaller than the inlet  32 . 
     The other aspects of the present embodiment are the same as those of the first embodiment, and operations and effects similar to those of the first embodiment are exerted in the present embodiment as well. 
       FIG. 3  illustrates the vapor deposition apparatus  1 , the crucible  4  and the vapor deposition method according to a third embodiment of the present invention. In the present embodiment, the position of the orifice  31  as the second guide passage  14  is different from that of the first embodiment. More specifically, in the first embodiment, the orifice  31  as the second guide passage  14  is formed at the middle part of the second wall section  22  of the crucible  4 , whereas in the present embodiment, the orifice  31  is formed at a boundary position between the second wall section  22  and the third wall section  23  so as to penetrate the second wall section  22 . Forming the second guide passage  14  at such a position allows the vaporized material to be sent via the third wall section  23  to the second guide passage  14  above. 
     The other aspects of the present embodiment are the same as those of the first embodiment, and operations and effects similar to those of the first embodiment are exerted in the present embodiment as well. 
       FIG. 4  illustrates a fourth embodiment of the vapor deposition apparatus  1 , the crucible  4  and the vapor deposition method according to the present invention. In the present embodiment, the structure of the second guide passage  14  is different from that of the first embodiment. More specifically, in the present embodiment, a protrusion  41  that protrudes outward is formed on an outer surface of the second wall section  22  of the crucible  4 . Furthermore, the second guide passage  14  is formed so as to penetrate this protrusion  41 . 
     In the present embodiment, a cylindrical member  42  is used as the protrusion  41 . This cylindrical member  42  includes an orifice  43  that penetrates along its cylinder center direction. The diameter of this orifice  43  is constant throughout the overall length in the cylinder center direction of the cylindrical member  42 . Therefore, the diameter at one end in the length direction is equal to the diameter at the other end of this cylindrical member  42 . Moreover, the cylindrical member  42  includes a flange  44  at the one end in its cylinder center direction. The diameter of the orifice  31  formed in the second wall section  22  of the crucible  4  is substantially equal to the diameter of the orifice  43  of the cylindrical member  42 . 
     The cylindrical member  42  is configured integrally with the second wall section  22  by fixing the flange  44  at a predetermined position on the outer surface of the second wall section  22 . In this case, the cylindrical member  42  is fixed to the second wall section  22  so that the orifice  31  formed in the second wall section  22  coincides with the orifice  43  of the cylindrical member  42 . This causes the orifice  31  of the second wall section  22  to communicate with the orifice  43  of the cylindrical member  42 . In this configuration, in the second guide passage  14  of the present embodiment, the inside opening of the orifice  31  formed in the second wall section  22  constitutes the inlet  32  for the vaporized material. Moreover, the opening outside the cylindrical member  42  constitutes the outlet  33  for the vaporized material. 
     With the above-described configuration, in the present embodiment, the protrusion  41  (cylindrical member  42 ) allows the second guide passage  14  to extend out of the crucible  4 . That is, the crucible  4  allows the length of the second guide passage  14  to be greater compared to the first embodiment. Compared to the first embodiment, the present embodiment can increase the spacing between the sensor and the crucible. This provides particularly effective measures, for example, for when the measuring accuracy deteriorates under influences of radiant heat from the crucible. 
     The other aspects of the present embodiment are the same as those of the first embodiment, and operations and effects similar to those of the first embodiment are exerted in the present embodiment as well. 
       FIG. 5  illustrates a fifth embodiment of the vapor deposition apparatus  1 , the crucible  4  and the vapor deposition method according to the present invention. The present embodiment is different from the fourth embodiment in the configuration of the second guide passage  14 . More specifically, the present embodiment as well as the fourth embodiment adopts the cylindrical member  42  as the protrusion  41 , and this cylindrical member  42  is configured so that the diameter at one end thereof in the cylinder center direction is different from the diameter at the other end thereof. More specifically, in this cylindrical member  42 , the diameter at one end on the side on which the flange  44  is formed is larger and the diameter at the other end on the side opposite to the sensor  5  is smaller. The diameter of the orifice  31  formed in the second wall section  22  is substantially equal to the diameter at the one end of the cylindrical member  42 . 
     According to this configuration, in the second guide passage  14  of the present embodiment, the diameter of the inlet  32  of the vaporized material is larger and the diameter of the outlet  33  is smaller. Therefore, in the present embodiment, more vaporized material can be introduced from the inlet  32  of the second guide passage  14  and the vaporized material with a higher density can be emitted toward the sensor  5  from the outlet  33  formed to be smaller than the inlet  32 . 
     The other aspects of the present embodiment are the same as those of the fourth embodiment, and operations and effects similar to those of the fourth embodiment are exerted in the present embodiment as well. 
       FIG. 6  illustrates a sixth embodiment of the vapor deposition apparatus  1 , the crucible  4  and the vapor deposition method according to the present invention. The present embodiment is different from the fourth embodiment in that a protrusion  51  that protrudes inside the crucible  4  is formed on an inner surface side of the second wall section  22  so as to guide the vaporized material that passes through the first guide passage  12  to the second guide passage  14 . This protrusion  51  is fixed to the inner surface of the second wall section  22  at a position between the inlet  32  of the second guide passage  14  formed in the second wall section  22  and the third wall section  23 . Furthermore, this protrusion  51  is formed into a planar shape, for example, and provided at a position proximate to the inlet  32  of the second guide passage  14 . 
     As shown above, with the planar protrusion  51  formed at the predetermined position on the inner surface of the second wall section  22 , the vaporized material that passes through the first guide passage  12  can be guided to the second guide passage  14  via this protrusion  51 . 
     The other aspects of the present embodiment are the same as those of the fourth embodiment, and operations and effects similar to those of the fourth embodiment are exerted in the present embodiment as well. 
     The crucible, the vapor deposition apparatus and the vapor deposition method according to the present invention are not limited to the configurations of the above-described embodiments. The crucible, vapor deposition apparatus and vapor deposition method according to the present invention are not limited to the above-described operations and effects, either. The crucible, the vapor deposition apparatus and the vapor deposition method according to the present invention can be modified in various ways without departing from the spirit and scope of the present invention. 
     For example, although an example has been described in the above-described embodiments, where the second guide passage  14  is formed in the second wall section  22  of the crucible  4 , the second guide passage  14  may also be formed in the first, and third to fifth wall sections other than the second wall section  22 . 
     Although an example has been described in the fourth to sixth embodiments, where the cylindrical member  42  is used as the protrusion, without being limited to this, a polygonal, oval or modified cylindrical member may also be used. Moreover, radiating fins may also be provided on the outer surface of this protrusion so as to improve cooling performance of the vaporized material in this protrusion. 
     Furthermore, instead of the cylindrical member, the protrusion  41  may be formed by increasing the thickness of part of the second wall section  22  compared to the rest of the second wall section  22 , and the orifice  31  may be formed so as to penetrate this protrusion  41  to thereby configure the second guide passage  14 . 
     In addition, a plurality of second guide passages  14  may be formed in the crucible  4 . In this case, a closing member may be provided which closes each inlet  32  or each outlet  33  of the second guide passages  14  in an openable/closable manner and the respective second guide passages  14  may be used as required. 
     REFERENCE SIGNS LIST 
     
         
           1  . . . Vapor deposition apparatus 
           2  . . . Substrate to be treated 
           3  . . . Vapor deposition source 
           4  . . . Crucible 
           5  . . . Sensor 
           5   a  . . . Detection surface 
           11  . . . Storage section 
           12  . . . First guide passage 
           13  . . . Emission port 
           14  . . . Second guide passage 
           16  . . . Bottom wall section 
           17  . . . Side wall section 
           21  . . . First wall section 
           22  . . . Second wall section 
           23  . . . Third wall section 
           31  . . . Orifice 
           32  . . . Inlet 
           33  . . . Outlet 
           41  . . . Protrusion 
           42  . . . Cylindrical member 
           43  . . . Orifice 
           44  . . . Flange section 
           51  . . . Protrusion 
           101  . . . Vapor deposition source 
           102  . . . Storage section 
           103  . . . Substrate to be treated 
           104  . . . Guide passage 
           105  . . . Crucible