Abstract:
An organic material for a light emitting device is deposited over a substrate by evaporating the organic material from an evaporation source. The evaporation source comprises a plurality of discrete evaporation cells separated from each other, wherein each of the plurality of discrete evaporation cells contains the organic material. The evaporation source has a length along a first direction and a width along a second direction orthogonal to the first direction, the length being greater than the width. The plurality of discrete evaporation cells is arranged along the first direction. When the organic material is evaporated, a relative location of the evaporation source with respect to the substrate is changed along the second direction, and the evaporation of the organic material is initiated by heating the plurality of discrete evaporation cells.

Description:
The present application is a continuation of U.S. application Ser. No. 12/467,497, filed May 18, 2009 (now U.S. Pat. No. 8,968,823 issued Mar. 3, 2015) which is a divisional of U.S. application Ser. No. 09/747,731, filed Dec. 22, 2000 (now U.S. Pat. No. 8,119,189 issued Feb. 21, 2012), which are all incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus or a method for forming a film used in manufacturing an EL (electroluminescence) element having a structure composed of an anode, a cathode, and sandwiching between the anode and the cathode a light emitting material, in particular a self-luminescing organic material (hereafter referred to as an organic EL material), from which EL (Electro Luminescence) is obtained. 
     2. Description of the Related Art 
     There are two types of EL display devices, a passive (a simple matrix), and an active (an active matrix), and development of both is being enthusiastically performed. In particular, active matrix EL display devices are in the spotlight at present. Furthermore, organic materials and inorganic materials exist for an EL material which becomes a light emitting layer of an EL element, and in addition organic materials are divided into low molecular weight (monomer) organic EL materials and high molecular weight (polymer) organic EL materials. Both are being vigorously researched, but a film of a low molecular weight organic EL material is mainly formed by evaporation, while a film of a high polymer organic EL material is mainly formed by application. 
     In order to manufacture a color display EL display device, it is necessary to form films of EL materials which emit different colors, for each pixel. However, in general EL materials are weak with respect to water and oxygen, and patterning by photolithography cannot be performed. It is therefore necessary to form the films at the same time as patterning. 
     The most general method is a method for forming a mask, made from a metallic plate or a glass plate and having an open portion formed in it, between the substrate onto which a film is formed and an evaporation source. In this case, the vaporized EL material from the evaporation source passes through only the open portion to thereby form the film selectively, and therefore it is possible to form an EL layer in which film formation and patterning are performed simultaneously. 
     With a conventional evaporation apparatus, the EL material which flies off in a radial shape from one evaporation source accumulates on a substrate, forming a thin film, and therefore, considering the distance that the EL material covers, a way of substrate positioning was devised. For example, a method of fixing a substrate to a circular cone shaped substrate holder, making the distances from the evaporation source to the substrate all equal, is performed. 
     However, when employing a multi-beveling process in which a plurality of panels are manufactured on a large size substrate, the substrate holder becomes extremely large if the above stated process is performed, and this leads to the main body of the film formation apparatus becoming large. Further, the substrate is planar when performing by single wafer processing as well, and therefore the distances from the evaporation source differs within the surface of the substrate, and a problem remains in that it is difficult to deposit at a uniform film thickness. 
     In addition, if the distance between the evaporation source and the shadow mask is not made longer when using a large size substrate, the vaporized EL material does not sufficiently spread, and it becomes difficult to form a uniform thin film over the entire substrate surface. Maintaining this distance also encourages making the apparatus large size. 
     SUMMARY OF THE INVENTION 
     The present invention is made in view of the above stated problems, and an object of the present invention is to provide a film formation apparatus capable of forming a thin film having a highly uniform film thickness distribution at high throughput. Further, an object of the present invention is to provide a method of forming a film using the film formation apparatus of the present invention. 
     An evaporation source in which an evaporation cell having a longitudinal direction (a portion in which a thin film material for evaporation is placed), or a plurality of the evaporation cells, are formed is used in the present invention. By moving the evaporation source in a direction perpendicular to the longitudinal direction of the evaporation source, a thin film is formed. Note that, “having a longitudinal direction” indicates a long and thin rectangular shape, a long and thin elliptical shape, or a linear shape. It is preferable that the length in the longitudinal direction be longer than the length of one side of a substrate for the present invention because processing can be performed in one sweep. Specifically, the length may be from 300 mm to 1200 mm (typically between 600 and 800 mm). 
     The positional relationship between the evaporation source of the present invention and the substrate is shown in  FIGS. 1A to 1C .  FIG. 1A  is a top view,  FIG. 1B  is a cross sectional diagram of  FIG. 1A  cut along the line segment B-B′, and  FIG. 10  is a cross sectional diagram of  FIG. 1A  cut along the line segment C-C′. Note that, common symbols are used in  FIGS. 1A to 10 . 
     As shown in  FIG. 1A , a shadow mask  102  is placed below a substrate  101 , and in addition, a rectangular shaped evaporation source  104 , in which a plurality of evaporation cells  103  are lined up on a straight line, is placed below the shadow mask  102 . Note that, throughout this specification, the term substrate includes a substrate and thin films formed on that substrate. Further, the term substrate surface indicates the substrate surface on which the thin films are formed. 
     The length of the longitudinal direction of the evaporation source  104  is longer than the length of one side of the substrate  101 , and a mechanism for moving the evaporation source  104  in a direction shown by an arrow (a direction perpendicular to the longitudinal direction of the evaporation source  104 ) is prepared. By then moving the evaporation source  104 , a thin film can be formed over the entire surface of the substrate. Note that, when the length of the longitudinal direction is shorter than that of one side of the substrate, the thin film may be formed by repeating a plurality of scans. Furthermore, a lamination of the same thin film may be formed by repeatedly moving the evaporation source  104 . 
     The thin film material vaporized by each of the evaporation cells  103  is scattered in the upward direction, passes through open portions (not shown in the figures) formed in the shadow mask  102 , and accumulates on the substrate  101 . The thin film is thus selectively deposited on the substrate  101 . A region in which the thin film material scattered from one evaporation cell  103  forms a film overlaps with a region in which the thin film material scattered from an adjoining evaporation cell  103  forms a film. By mutually overlapping the regions in which the film is deposited, the film is formed in a rectangular shape region. 
     The uniformity in film thickness of a thin film can thus be greatly improved with the present invention by using the evaporation source having a plurality of evaporation cells lined up, and by irradiating from a line instead of conventional irradiation from a point. In addition, by moving the rectangular shape evaporation source below the substrate surface, film formation can be performed at high throughput. 
     Additionally, it is not necessary to make the distance between the evaporation source  104  and the shadow mask  102  longer with the present invention, and evaporation can be performed in a state of extreme closeness. This is because a plurality of evaporation cells are formed in alignment, and even if the scattering distance of the thin film material is short, film formation can be performed simultaneously from the central portion to the edge portion of the substrate. This effect is greater the higher the density at which the evaporation cells  103  are lined up. 
     The distance from the evaporation source  104  to the shadow mask  102  is not particularly limited because it differs depending upon the density at which the evaporation cells  103  are formed. However, if it is too close, then it becomes difficult to form a uniform film from the center portion to the edge portion, and if it is too far, there will be no change from conventional evaporation by irradiating from a point. Therefore, if the gap between evaporation cells  103  is taken as “a”, it is preferable to make the distance between the evaporation source  104  and the shadow mask  102  from 2a to 100a (more preferably from 5a to 50a). 
     With the film formation apparatus of the present invention structured as above, uniformity of the distribution of film thickness of a thin film in a rectangular shape, elliptical shape, or a linear shape region is maintained by using the evaporation source, and by moving the evaporation source on top of that region, it becomes possible to form a thin film having high uniformity over the entire surface of the substrate. Further, this is not evaporation from a point, and therefore the distance between the evaporation source and the substrate can be made shorter, and the uniformity of film thickness can be further increased. 
     Furthermore, it is effective to add means for generating a plasma within a chamber in the film formation apparatus of the present invention. By performing a plasma process in accordance with oxygen gas or a plasma process in accordance with a gas containing fluorine, thin films deposited on the chamber walls are removed, and cleaning of the inside of the chamber can be performed. Parallel-plate electrodes may be formed within the chamber, and a plasma may be generated between the plates as the means for generating the plasma. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIGS. 1A to 1C  are diagrams showing a structure of an evaporation source; 
         FIGS. 2A and 2B  are diagrams showing a structure of an evaporation chamber; 
         FIG. 3  is a diagram showing a structure of an evaporation chamber; 
         FIG. 4  is a diagram showing a structure of a film formation apparatus; 
         FIG. 5  is a diagram showing a structure of a film formation apparatus; 
         FIG. 6  is a diagram showing a structure of a film formation apparatus; 
         FIG. 7  is a diagram showing a structure of a film formation apparatus; and 
         FIG. 8  is a diagram showing a structure of a film formation apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment Mode 
     A structure of an evaporation chamber prepared in a film formation apparatus of the present invention is shown in  FIGS. 2A and 2B .  FIG. 2A  is a top view of the evaporation chamber, and  FIG. 2B  is a cross sectional diagram. Note that common symbols are used for common portions. Further, an example of forming an EL (electroluminescence) film as a thin film is shown in the embodiment mode. 
     In  FIG. 2A , reference numeral  201  denotes a chamber, and reference numeral  202  denotes a substrate conveyor opening, from which substrate is conveyed to the inside portion of the chamber  201 . A conveyed substrate  203  is set in a substrate holder  204 , and is conveyed in to a film formation portion  206  by a conveyor rail  205   a , as shown by an arrow  205   b.    
     When the substrate  203  is conveyed to a film formation portion  206 , a shadow mask  208  fixed to a mask holder  207  approaches the substrate  203 . Note that, a metallic plate is used as the material of the shadow mask  208  in this embodiment mode. (See  FIG. 2B ) Further, open portions  209  are formed having a rectangular shape, elliptical shape, or linear shape in the shadow mask  208  in this embodiment mode. The shape of the opening portions is not limited, of course, and a matrix shape or a net shape may also be formed. 
     At this point in the embodiment mode, this is a structure in which an electromagnet  210  approaches the substrate  203 , as shown in  FIG. 2B . When a magnetic field is formed by the electromagnet  210 , the shadow mask  208  is drawn to the substrate  203 , and is maintained at a predetermined gap. This gap is secured by a plurality of projections  301  formed in the shadow mask  208 , as shown in FIG.  3 . 
     This type of structure is particularly effective when the substrate  203  is a large size substrate exceeding 300 mm. If the substrate  203  is large size, then deflection (warp) is generated by the weight of the substrate itself. However, the substrate  203  can also be pulled toward the electromagnet  210  and the flexure can be canceled provided that the shadow mask  208  is drawn toward the substrate  203  side by the electromagnet  210 . Note that, as shown in  FIG. 4 , it is preferable to form projections  401  in the electromagnet  210 , and to maintain a gap between the substrate  203  and the electromagnet  210 . 
     When the gap between the substrate  203  and the shadow mask  208  is secured, an evaporation source  212 , on which evaporation cells  211  having a longitudinal direction are formed, is then moved in the direction of the arrow  213 . An EL material formed in the inside portion of the evaporation cells is vaporized by being heated while being moved, and is scattered within the chamber of the film formation portion  206 . Note that the distance between the evaporation source  212  and the substrate  203  can be made extremely short for the case of the present invention, and therefore adhesion of the EL material to a drive portion (a portion for driving the evaporation source, the substrate holder, or the mask holder) within the chamber can be minimized. 
     The evaporation source  212  is scanned from one end of the substrate  203  to the other end. As shown in  FIG. 2A , the length of the longitudinal direction of the evaporation source  212  is sufficiently long in the embodiment mode, and therefore it can be moved over the entire surface of the substrate  203  by scanning once. 
     After a film is formed from a red, green, or blue color EL material (red here) as above, the magnetic field of the electromagnet  210  is switched off, the mask holder  207  is dropped down, and the distance between the shadow mask  208  and the substrate  203  increases. The substrate holder  204  is then shifted over by one pixel portion, the mask holder  207  is raised again, and the shadow mask  208  and the substrate  203  are made to come closer. In addition, a magnetic field is formed by the electromagnet  210 , and deflection (warp) of the shadow mask  208  and the substrate  203  is eliminated. The evaporation cell is changed next, and film formation of a red, green, or blue EL material (green here) is performed. 
     Note that, a structure in which the substrate holder  204  is shifted by one pixel portion is shown here, but the mask holder  204  may also be shifted by one pixel portion. 
     After all film formation of red, green, and blue EL materials by this type of repetition, the substrate  203  is lastly conveyed to the substrate conveyor opening  202 , and is removed from the chamber  201  by a robot arm (not shown in the figures). Film formation of the EL films using the present invention is thus completed. 
     Embodiment 1 
     An explanation of a film formation apparatus of the present invention is explained using  FIG. 5 . In  FIG. 5 , reference numeral  501  denotes a conveyor chamber. A conveyor mechanism  502  is prepared in the conveyor chamber  501 , and conveyance of a substrate  503  is performed. The conveyor chamber  501  has a reduced pressure atmosphere, and is connected to each processing chamber by a gate. Delivery of the substrate to each processing chamber is performed by the conveyor mechanism  502  when the gates are open. Further, it is possible to use an evacuation pump such as an oil-sealed rotary pump, a mechanical booster pump, a turbo-molecular pump, and a cryo-pump in lowering the pressure of the conveyor chamber  501 , but a cryo-pump, which is effective in removing moisture, is preferable. 
     An explanation regarding each processing chamber is made below. Note that the conveyor chamber  501  has a reduced pressure atmosphere, and therefore an evacuation pump (not shown in the figure) is prepared in each processing chamber directly connected to the conveyor chamber  501 . The above stated oil-sealed rotary pump, mechanical booster pump, turbo-molecular pump, and cryo-pump are used as the evacuation pump. 
     First, reference numeral  504  denotes a load chamber for performing substrate setting, and it is also an unload chamber. The load chamber  504  is connected to the conveyor chamber  501  by a gate  500   a , and a carrier (not shown in the figure) on which the substrate  503  is set is arranged here. Note that the load chamber  504  may also be separated into a substrate loading chamber and a substrate unloading chamber. Further, the above evacuation pump and a purge line for introducing high purity nitrogen gas or noble gas are prepared for the load chamber  504 . 
     Note that a substrate on which process through the formation of a transparent conducting film, which becomes an anode of an EL element has been conducted, is used as the substrate  503  in Embodiment 1. The substrate  503  is set in the carrier with the surface on which the films are formed facing downward. This is in order to make a face-down method (also referred to as a deposition-up method) easier to perform when later performing film formation by evaporation. The face down method denotes a method in which film formation is performed with the substrate surface onto which a film is to be formed facing downward, and adhesion of refuse (dirt) or the like can be suppressed by this method. 
     Next, reference numeral  505  denotes a processing chamber for processing a surface of an anode or a cathode of an EL element (in Embodiment 1, an anode), and the processing chamber  505  is connected to the conveyor chamber  501  by a gate  500   b . The processing chamber can be changed variously depending upon the manufacturing process of the EL element, and in Embodiment 1 heat treatment of the surface of the anode made from the transparent conducting film can be performed at between 100 and 120° C. in oxygen while irradiating ultraviolet light. This type of pre-process is effective when processing the anode surface of the EL element. 
     Next, reference numeral  506  denotes an evaporation chamber for film deposition of an organic EL material by evaporation, and is referred to as an evaporation chamber (A). The evaporation chamber (A)  506  is connected to the conveyor chamber  501  through a gate  500   c . In Embodiment 1 an evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (A)  506 . 
     In a film formation portion  507  of the evaporation chamber (A)  506 , first a hole injecting layer is deposited over the entire substrate surface, then a light emitting layer for emitting red color light is formed, next a light emitting layer for emitting green color light is formed, and lastly a light emitting layer for emitting blue color light is formed. Note that any known materials may be used as the hole injecting layer, the red color light emitting layer, the green color light emitting layer, and the blue color light emitting layer. 
     The evaporation chamber (A)  506  has a structure which is capable of switching in correspondence with the type of organic material of the film formation evaporation source. Namely, a preparation chamber  508  for storing a plurality of types of evaporation sources is connected to the evaporation chamber (A)  506 , and evaporation source switching is performed by an internal conveyor mechanism. The evaporation source therefore changes when the organic EL material for film formation changes. Further, the same mask of shadow mask is moved by one pixel portion whenever the organic EL material for film formation is switched. 
     Note that  FIGS. 2A and 2B  may be referred to regarding film formation processes occurring within the evaporation chamber (A)  506 . 
     Next, reference numeral  509  denotes an evaporation chamber for film formation of a conducting film (a metallic film which becomes a cathode is used in Embodiment 1), which becomes an anode or a cathode of the EL element, by evaporation, and is referred to as an evaporation chamber (B). The evaporation chamber (B)  509  is connected to the conveyor chamber  501  through a gate  500   d . An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (B)  509  in Embodiment 1. In a film formation portion  510  within the evaporation chamber (B)  509 , an Al—Li alloy film (an alloy film of aluminum and lithium) is deposited as the conducting film which becomes the EL element cathode. 
     Note that it is also possible to co-evaporate an element residing in group 1 or group 2 of the periodic table, and aluminum. Co-evaporation refers to evaporation in which cells are heated at the same time, and different materials are combined at the stage of film formation. 
     Next, reference numeral  511  denotes a sealing chamber (also referred to as an enclosing chamber or a globe box), and is connected to the load chamber  504  through a gate  500   e . A process for final hermetic sealing of the EL element is performed in the sealing chamber  511 . This process is one in which the formed EL element is protected from oxygen and moisture, and a means for mechanically sealing by a sealing material, or a means for sealing by a thermally hardened resin or an ultraviolet light hardened resin is used. 
     Glass, ceramic, plastic, and metal can be used as the sealing material, but when light is irradiated onto the sealing material side, the material must have transparency. Further, when the sealing material and substrate on which the above EL element is formed are joined using a thermal hardened resin or an ultraviolet light hardened resin, the resin is hardened by heat treatment or by ultraviolet light irradiation processing, forming an airtight space. It is also effective to form a drying agent, typically barium oxide, within the airtight space. 
     Further, it is also possible to fill the space between the sealing material and the substrate on which the EL element is formed by a thermal hardened resin or an ultraviolet light hardened resin. In this case, it is effective to add a drying agent, typically barium oxide, within the thermal hardened resin or the ultraviolet light hardened resin. 
     A mechanism for irradiating ultraviolet light (hereafter referred to as an ultraviolet light irradiation mechanism)  512  is formed on an internal portion of the sealing chamber  511 , and the film formation apparatus shown in  FIG. 5  has a structure in which an ultraviolet light hardened resin is hardened by ultraviolet light emitted from the ultraviolet light irradiation mechanism  512 . Further, it is possible to reduce the pressure of the inside portion of the sealing chamber  511  by attaching an evacuation pump. When mechanically performing the above sealing processes by using robot operation, oxygen and moisture can be prevented from mixing in by performing the processes under reduced pressure. Furthermore, it is also possible to pressurize the inside portion of the sealing chamber  511 . In this case pressurization is performed by a high purity nitrogen gas or noble gas while purging, and an incursion of a contaminant such as oxygen from the atmosphere is prevented. 
     Next, a delivery chamber (a pass box)  513  is connected to the sealing chamber  511 . A conveyor mechanism (B)  514  is formed in the delivery chamber  513 , and the substrate on which the EL element has been completely sealed in the sealing chamber  511  is conveyed to the delivery chamber  513 . It is possible to also make the delivery chamber  513  reduced pressure by attaching an evacuation pump. The delivery chamber  513  is equipment used so that the sealing chamber  511  is not directly exposed to the atmosphere, and the substrate is removed from here. 
     It thus becomes possible to manufacture an EL display device having high reliability by using the film formation apparatus shown in  FIG. 5  because processing can be finished up through the point, without exposure to the atmosphere, at which the EL element is completely sealed into an airtight space. 
     Embodiment 2 
     A case of using a film formation apparatus of the present invention in a multi-chamber method (also referred to as a cluster tool method) is explained using  FIG. 6 . Reference numeral  601  denotes a conveyor chamber in  FIG. 6 . A conveyor mechanism (A)  602  is prepared in the conveyor chamber  601 , and conveyance of a substrate  603  is performed. The conveyor chamber  601  has a reduced pressure atmosphere, and is connected to each processing chamber by a gate. Delivery of the substrate to each processing chamber is performed by the conveyor mechanism (A)  602  when the gates are open. Further, it is possible to use an evacuation pump such as an oil-sealed rotary pump, a mechanical booster pump, a turbo-molecular pump, and a cryo-pump in lowering the pressure of the conveyor chamber  601 , but a cryo-pump, which is effective in removing moisture, is preferable. 
     An explanation regarding each processing chamber is made below. Note that the conveyor chamber  601  has a reduced pressure atmosphere, and therefore an evacuation pump (not shown in the figure) is prepared in each processing chamber directly connected to the conveyor chamber  601 . The above stated oil-sealed rotary pump, mechanical booster pump, turbo-molecular pump, and cryo-pump is used as the evacuation pump. 
     First, reference numeral  604  denotes a load chamber for performing substrate setting, and it is also called an unload chamber. The load chamber  604  is connected to the conveyor chamber  601  by a gate  600   a , and a carrier (not shown in the figure) on which the substrate  603  is set is arranged here. Note that the load chamber  604  may also be separated into a substrate loading chamber and a substrate unloading chamber. Further, the above evacuation pump and a purge line for introducing high purity nitrogen gas or noble gas are prepared for the load chamber  604 . 
     Next, reference numeral  605  denotes a preprocessing chamber for processing a surface of an anode or a cathode of an EL element (in Embodiment 2, an anode), and the processing chamber  605  is connected to the conveyor chamber  601  by a gate  600   b . The preprocessing chamber can be changed variously depending upon the manufacturing process of the EL element, and in Embodiment 2 heat treatment of the surface of the anode made from the transparent conducting film can be performed at between 100 and 120° C. in oxygen while irradiating ultraviolet light. This type of pre-process is effective when processing the anode surface of the EL element. 
     Next, reference numeral  606  denotes an evaporation chamber for film deposition of an organic EL material by evaporation, and is referred to as an evaporation chamber (A). The evaporation chamber (A)  606  is connected to the conveyor chamber  601  through a gate  600   c . In Embodiment 2 an evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (A)  606 . 
     In a film formation portion  607  of the evaporation chamber (A)  606 , a hole injecting layer is first deposited over the entire substrate surface, then a light emitting layer for emitting red color light is formed. Accordingly, an evaporation source and a shadow mask are provided with two types of each corresponding to the organic material to be the hole injecting layer and the red light emitting layer, and are structured to be capable of switching. Note that known materials may be used as the hole injecting layer, and the red color light emitting layer. 
     Next, reference numeral  608  denotes an evaporation chamber for film formation of an organic EL material by evaporation, and is referred to as an evaporation chamber (B). The evaporation chamber (B)  608  is connected to the conveyor chamber  601  through a gate  600   d . In Embodiment 2, an evaporation chamber with the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (B)  608 . A light emitting layer for emitting green color light is deposited in a film formation portion  609  within the evaporation chamber (B)  608  in Embodiment 2. Note that a known material may be used as the light emitting layer for emitting green color light in Embodiment 2. 
     Next, reference numeral  610  denotes an evaporation chamber for film formation of an organic EL material by evaporation, and is referred to as an evaporation chamber (C). The evaporation chamber (C)  610  is connected to the conveyor chamber  601  through a gate  600   e . In Embodiment 2, an evaporation chamber with the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (C)  610 . Alight emitting layer for emitting blue color light is deposited in a film formation portion  611  within the evaporation chamber (C)  610  in Embodiment 2. Note that a known material may be used as the light emitting layer for emitting blue color light in Embodiment 2. 
     Next, reference numeral  612  denotes an evaporation chamber for film formation of a conducting film, which becomes an anode or a cathode of the EL element, by evaporation (a metallic film which becomes a cathode is used in Embodiment 2), and is referred to as an evaporation chamber (D). The evaporation chamber (D)  612  is connected to the conveyor chamber  601  through a gate  600   f . An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (D)  612  in Embodiment 2. In a film formation portion  613  within the evaporation chamber (D)  612 , an Al—Li alloy film (an alloy film of aluminum and lithium) is deposited as the conducting film which becomes the EL element cathode. Note that it is also possible to co-evaporate an element residing in group 1 or group 2 of the periodic table, and aluminum. 
     Next, reference numeral  614  denotes a sealing chamber, and is connected to the load chamber  604  through a gate  600   g . For explanation of the sealing chamber  614  refer to Embodiment 1. Further, an ultraviolet light irradiation mechanism  615  is formed in the inside portion of the sealing chamber  614 , similar to Embodiment 1. In addition, a delivery chamber  616  is connected to the sealing chamber  615 . A conveyor mechanism (B)  617  is formed in the delivery chamber  616 , and the substrate, on which the EL element has been completely sealed in the sealing chamber  614 , is conveyed to the delivery chamber  616 . Embodiment 1 may be referred to for an explanation of the delivery chamber  616 . 
     It thus becomes possible to manufacture an EL display device having high reliability by using the film formation apparatus shown in  FIG. 6  because processing can be finished up through the point, without exposure to the atmosphere, at which the EL element is completely sealed into an airtight space. 
     Embodiment 3 
     A case of using a film formation apparatus of the present invention in an in-line method is explained using  FIG. 7 . Reference numeral  701  denotes a load chamber in  FIG. 7 , and conveyance of a substrate is performed here. An evacuation system  700   a  is prepared in the load chamber  701 , and the evacuation system  700   a  has a structure containing a first valve  71 , a turbo-molecular pump  72 , a second valve  73 , and a rotary pump (oil-sealed rotary pump)  74 . 
     The first valve  71  is a main valve, and there are cases when it also combines a conductance valve, and there are also cases when a butterfly valve is used. The second valve  73  is a fore valve, and the second valve  73  is opened first, and the load chamber  701  is roughly reduced in pressure by the rotary pump  74 . The first valve  71  is opened next, and the pressure is reduced by the turbo-molecular pump  72  until a high vacuum is reached. Note that it is possible to use a mechanical booster pump or a cryo-pump as a substitute for the turbo-molecular pump, but the cryo-pump is particularly effective in removing moisture. 
     Next, reference numeral  702  denotes a preprocessing chamber for processing a surface of an anode or a cathode of an EL element (in Embodiment 3, an anode), and the preprocessing chamber  702  is prepared with an evacuation system  700   b . Further, it is hermetically sealed off from the load chamber  701  by a gate not shown in the figure. The preprocessing chamber  702  can be changed variously depending upon the manufacturing process of the EL element, and in Embodiment 3 heat treatment of the surface of the anode made from the transparent conducting film can be performed at between 100 and 120° C. in oxygen while irradiating ultraviolet light. 
     Next, reference numeral  703  denotes an evaporation chamber for film deposition of an organic. EL material by evaporation, and is referred to as an evaporation chamber (A). Further, it is hermetically sealed off from the load chamber  702  by a gate not shown in the figure. The evaporation chamber (A)  703  is prepared with an evacuation system  700   c . In Embodiment 3 an evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber (A)  703 . 
     A substrate  704  conveyed to the evaporation chamber (A)  703 , and an evaporation source  705  prepared in the evaporation chamber (A)  703 , are moved in the direction of the arrows, respectively, and film formation is performed. Note that  FIGS. 2A and 2B  may be referred to regarding detailed operation of the evaporation chamber (A)  703 . A hole injecting layer is deposited in the evaporation chamber (A)  703  in Embodiment 3. A known material may be used as the hole injecting layer. 
     Next, reference numeral  706  denotes an evaporation chamber for film formation of an organic EL material by evaporation, and is referred to as an evaporation chamber (B). The evaporation chamber (B)  706  is prepared with an evacuation system  700   d . Further, it is hermetically sealed off from the evacuation chamber (A)  703  by a gate not shown in the figure. An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is formed as the evaporation chamber (B)  706  in Embodiment 3. The explanation of  FIGS. 2A and 2B  may therefore be referred to regarding detailed operation of the evaporation chamber (B)  706 . Further, a light emitting layer for emitting red color light is deposited in the evaporation chamber (B)  706 . A known material may be used as the light emitting layer which emits red color light. 
     Next, reference numeral  707  denotes an evaporation chamber for film formation of an organic EL material by evaporation, and is referred to as an evaporation chamber (C). The evaporation chamber (C)  707  is prepared with an evacuation system  700   e . Further, it is hermetically sealed off from the evacuation chamber (B)  706  by a gate not shown in the figure. An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is formed as the evaporation chamber (C)  707  in Embodiment 3. The explanation of  FIGS. 2A and 2B  may therefore be referred to regarding detailed operation of the evaporation chamber (C)  707 . Further, a light emitting layer for emitting green color light is deposited in the evaporation chamber (C)  707 . A known material may be used as the light emitting layer which emits green color light. 
     Next, reference numeral  708  denotes an evaporation chamber for film formation of an organic EL element by evaporation, and is referred to as an evaporation chamber (D). The evaporation chamber (D)  708  is prepared with an evacuation system  700   f . Further, it is hermetically sealed off from the evacuation chamber (C)  707  by a gate not shown in the figure. An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is formed as the evaporation chamber (D)  708  in Embodiment 3. The explanation of  FIGS. 2A and 2B  may therefore be referred to regarding detailed operation of the evaporation chamber (D)  708 . Further, a light emitting layer for emitting blue color light is deposited in the evaporation chamber (D)  708 . A known material may be used as the light emitting layer which emits blue color light. 
     Next, reference numeral  709  denotes an evaporation chamber for film formation of a conducting film (a metallic film which becomes a cathode is used in Embodiment 3), which becomes an anode or a cathode of the EL element, by evaporation, and is referred to as an evaporation chamber (E). The evaporation chamber (E)  709  is prepared with an evacuation system  700   g . Further, it is hermetically sealed off from the evacuation chamber (D)  708  by a gate not shown in the figure. An evaporation chamber having the structure shown in  FIGS. 2A and 2B  is formed as the evaporation chamber (E)  709  in Embodiment 3. The explanation of  FIGS. 2A and 2B  may therefore be referred to regarding detailed operation of the evaporation chamber (E)  709 . 
     An Al—Li alloy film (an alloy film of aluminum and lithium) is deposited in the evaporation chamber (E)  709  as the conducting film which becomes the EL element cathode. Note that it is also possible to co-evaporate an element residing in group 1 or group  2  of the periodic table, and aluminum. 
     Next, reference numeral  710  denotes a sealing chamber, and it is prepared with an evacuation system  700   h . Further, it is hermetically sealed off from the evacuation chamber (E)  709  by a gate not shown in the figure. Embodiment 1 may be referred to regarding an explanation of the sealing chamber  710 . Furthermore, an ultraviolet light irradiation mechanism is provided on the inside portion of the sealing chamber  710 , similar to Embodiment 1. 
     Finally, reference numeral  711  denotes an unload chamber, and it is prepared with an evacuation system  700   i . The substrate on which the EL element is formed is removed from here. 
     It thus becomes possible to manufacture an EL display device having high reliability by using the film formation apparatus shown in  FIG. 7  because processing can be finished up through the point, without exposure to the atmosphere, at which the EL element is completely sealed into an airtight space. An EL display device can furthermore be manufactured at a high throughput in accordance with the in-line method. 
     Embodiment 4 
     A case of using a film formation apparatus of the present invention in an in-line method is explained using  FIG. 8 . Reference numeral  801  denotes a load chamber in  FIG. 8 , and conveyance of a substrate is performed here. An evacuation system  800   a  is prepared in the load chamber  801 , and the evacuation system  800   a  has a structure containing a first valve  81 , a turbo-molecular pump  82 , a second valve  83 , and a rotary pump (oil-sealed rotary pump)  84 . 
     Next, reference numeral  802  denotes a preprocessing chamber for processing a surface of an anode or a cathode of an EL element (in Embodiment 4, an anode), and the preprocessing chamber  802  is prepared with an evacuation system  800   b . Further, it is hermetically sealed off from the load chamber  801  by a gate not shown in the figure. The preprocessing chamber  802  can be changed variously depending upon the manufacturing process of the EL element, and in Embodiment 4 heat treatment of the surface of the anode made from the transparent conducting film can be performed at between 100 and 120° C. in oxygen while irradiating ultraviolet light. 
     Next, reference numeral  803  denotes an evaporation chamber for film deposition of an organic EL material by evaporation, and the evaporation chamber  803  is prepared with an evacuation system  800   c . In Embodiment 4 an evaporation chamber having the structure shown in  FIGS. 2A and 2B  is used as the evaporation chamber  803 . A substrate  804  conveyed to the evaporation chamber  803 , and an evaporation source  805  prepared in the evaporation chamber  803 , are moved in the direction of the arrows, respectively, and film formation is performed. 
     In Embodiment 4, it is preferable to switch the evaporation source  803  or the shadowmask (not shown) at the time of film deposition in the evaporation chamber  803  in order to form a conductive film to be hole injection layer, a red light emitting layer, a green light emitting layer, a blue light emitting layer or a cathode. In Embodiment 4, the evaporation chamber  803  is connected with a reserve chamber  806 , in which the evaporation source and the shadow mask are stored to switch appropriately. 
     Next, reference numeral  807  denotes a sealing chamber, and it is prepared with an evacuation system  800   d . Further, it is hermetically sealed off from the evacuation chamber  803  by a gate not shown in the figure. Embodiment 1 may be referred to regarding an explanation of the sealing chamber  807 . Furthermore, an ultraviolet light irradiation mechanism (not shown in the figure) is provided on the inside portion of the sealing chamber  807 , similar to Embodiment 1. 
     Finally, reference numeral  808  denotes an unload chamber, and it is prepared with an evacuation system  800   e . The substrate on which the EL element is formed is removed from here. 
     It thus becomes possible to manufacture an EL display device having high reliability by using the film formation apparatus shown in  FIG. 8  because processing can be finished up through to the point, at which the EL element is completely sealed into an airtight space without exposure to the atmosphere. An EL display device can furthermore be manufactured at a high throughput in accordance with the in-line method. 
     By using the film formation apparatus of the present invention, it becomes possible to perform film formation, at high throughput, of a thin film having high uniformity in its film thickness distribution on the substrate surface.