JP2011065967A - Heating and drying device for organic el - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome problems in a hot air circulation type multistage heating and drying device used as the heating and drying device for an organic EL, wherein even though the device has good space efficiency and can be made to be a device at relatively low cost, the device is not capable of keeping a heating furnace at an inert gas atmosphere when carrying in/out substrates, so that its process treatment time becomes long, thereby the device is not suitable for mass production facility as a property shows unevenness caused by deterioration of an organic function layer. <P>SOLUTION: The heating and drying device has a multistage load lock chamber 5 at a substrate carrying in/out part of the hot air circulation type multistage heating and drying device, so that the substrate A can be carried in/out by each stage while retaining the inert gas atmosphere and a heating temperature inside a heating furnace 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an apparatus for processing an organic film coated on a substrate, and more particularly to a heating and drying apparatus for organic EL used for manufacturing organic electroluminescence (hereinafter referred to as organic EL) including a drying step.

  An organic electroluminescent element (hereinafter referred to as an organic EL element), which is a kind of electroluminescent element, is a self-luminous all-solid-state element, and thus has high visibility, and is also an element compared to a cathode ray tube, a plasma display, and a liquid crystal display. Since the thickness of the substrate can be reduced and the driving power is also small, a wide range of applications are expected. In manufacturing an organic EL element, it is generally necessary to pattern an organic functional layer having a thickness of about several tens to several thousand nm on a substrate.

  The organic functional material includes a low molecular material and a high molecular material. Generally, the low molecular material is formed into a thin film by a resistance heating vapor deposition method or the like. At this time, patterning is performed using a fine pattern mask. However, this method has a problem that patterning accuracy is difficult to obtain as the substrate becomes larger.

  Further, in the vapor deposition method, since the vapor deposition source is usually a point shape like a pinhole or a crucible of a boat, it is difficult to form a layer with a uniform film thickness on a large-sized substrate. In many cases, the vapor deposition method is performed under a high vacuum, which requires a large vacuum apparatus.

  On the other hand, a method of forming a thin film by a wet process using a coating liquid (ink) in which an organic functional material is dissolved or dispersed in a solvent is being tried. Examples of wet coating methods for forming a thin film include spin coating, bar coating, and dip coating. In particular, in order to perform high-definition patterning, it is considered most effective to form a thin film by a printing method that specializes in painting and patterning.

  A method for producing an organic EL element by a printing method is very effective. In particular, when a polymer material is used, it is possible to easily form a flat and uniform organic functional layer on the substrate.

  However, since the organic functional layer printed on the substrate contains a solvent, a drying step for removing the solvent is required. As the method, a reduced pressure drying method (for example, Patent Document 1), a heat drying method (for example, Patent Document 2), a pressure heating drying method (for example, Patent Document 3), and the like have been proposed.

  In addition, drying for the purpose of removing a high boiling point solvent (hereinafter referred to as residual solvent) remaining in the organic functional layer and a long time of 10 minutes or more at a high temperature of about 100 to 200 ° C. for forming the organic functional layer. Need to be baked.

  It is known that the characteristics are influenced by the baking conditions of the organic functional layer. For example, when the organic functional layer is baked, variations in the in-plane temperature uniformity within the substrate also cause variations in the characteristics of the organic functional layer within the substrate surface. Cause the occurrence of

  Here, there are (1) a hot air circulation method, (2) a hot plate method, (3) a far-infrared method, and the like as a general heat drying apparatus for heating and drying a substrate. Among them, the hot air circulation type heating and drying apparatus has the advantage of being easily multi-staged and excellent in space efficiency, and can be realized at a lower cost than other types of heating and drying apparatuses (for example, Patent Document 4).

  Furthermore, as an advantage of the multi-stage hot air circulation heating and drying apparatus, it is not necessary to provide a substrate transport mechanism that can be a dust generation source in the heating furnace, and the substrate heating temperature is the same as the furnace atmosphere temperature. It is easy to control the temperature of the substrate.

  However, when heat-treating a substrate on which an organic functional layer is formed, there is a problem that when oxygen and water coexist at the time of heating, they cause a chemical reaction with the organic functional layer to deteriorate device characteristics. In particular, oxygen easily reacts with the double bond sites of π-electron molecules that are often used as functional materials. Therefore, when these organic functional layers are heated at high temperatures, they can be used in an inert gas atmosphere such as nitrogen or argon. It is necessary to do in.

  FIG. 2 shows the configuration of a conventional multistage heating and drying apparatus using a hot air circulation system. 2A shows a state when the substrate is carried in, and FIG. 2B shows a state when the substrate is heated.

  In this heating and drying apparatus, the inside of the main body 11 is a heating furnace 12, and an opening 13 that functions as a substrate loading / unloading portion with respect to the heating furnace 12 is formed on the front surface of the main body 11, and this opening 13 is formed as shown in FIG. The shutter 14 shown in FIG. In the heating furnace 12, a substrate rack 16 is installed which is formed by laying a plurality of horizontal shelves 15 vertically.

  As shown in FIG. 2A, the substrate A is carried onto each shelf 15 of the substrate rack 16 in the heating furnace 12 from the opening 13 using the transfer robot 17. Then, as shown in FIG. 2B, the opening 13 is sealed with a shutter 14, and the gas in the heating furnace 12 is replaced with an inert gas to maintain an inert gas atmosphere. The substrate A is heated to a temperature of 200 ° C. or higher by a hot air circulation method. After the heat treatment, the shutter 14 is opened, and each substrate A is taken out from the heating furnace 12 using the transfer robot 17.

JP-A-9-97679 JP 2002-31567 A JP 2005-26000 A Japanese Patent No. 3714416

  In such a conventional heat drying apparatus, during the process of carrying the substrate A into the substrate rack 16 in the heating furnace 12 from the outside, the atmosphere enters the heating furnace 12 through the opening 13, so the inside of the heating furnace 12 is inactive. The gas atmosphere cannot be maintained. Since the air enters, the substrate carrying-in process is performed at a temperature of 50 ° C. or lower.

  After completion of the substrate carrying-in process, as shown in FIG. 2B, the inside of the heating furnace 12 is shut off from the atmosphere and replaced with an inert gas atmosphere, and finally the heating in the heating furnace 12 can be started after the completion of the replacement. become able to do. In addition, even after the heat treatment is finished, if the temperature in the heating furnace 12 is not cooled to a low temperature of at least 50 ° C., the substrate A after the heat treatment can be taken out, or the substrate A on which the heat treatment can be continued is placed in the heating furnace 2 It is not possible to carry it in.

  Further, in the hot air circulation method, when the furnace atmosphere temperature is kept constant at a high temperature of 200 ° C. or higher, the air permeability can be kept sufficiently by opening the space between the substrates A arranged in multiple stages in the heating furnace 12. Although it is possible to suppress the variation in the in-plane temperature of the substrate A within about 5 ° C., when the temperature in the furnace is increased from about room temperature to a temperature higher than 200 ° C., the temperature in the furnace is rapidly increased. If this is done, a large temperature difference occurs depending on the flow direction of the hot air in the furnace. Therefore, in order to suppress the temperature difference in the furnace, it is necessary to increase the temperature in the furnace over time. As a guideline, it takes at least 30 minutes to raise the furnace temperature from room temperature to 200 ° C.

  As described above, the conventional hot air circulation type multi-stage heating and drying apparatus requires a very long processing time and is not suitable for mass production equipment.

  In other words, the organic EL heating and drying apparatus needs to perform the heat treatment in a vacuum or in an inert gas atmosphere, and further needs to raise the temperature uniformly in the substrate surface. It takes a very long time from the substrate loading process to the substrate unloading process through the process of replacing the inside of the heating furnace with an inert gas atmosphere, the temperature raising process, the heating process at a predetermined temperature, and the cooling process in the heating furnace. There is a problem that it is not suitable for mass production equipment.

  In addition, it is known that the characteristics of the organic functional layer gradually deteriorate in the atmosphere even at room temperature. For example, when the organic functional layer before baking is left in the air for 1 hour, the current efficiency of the organic EL element is about May decrease by 10%. In the conventional heating and drying apparatus, since the process of carrying in the substrate is performed in the atmosphere, if the substrate carrying-in process takes time, the characteristics of the organic functional layer are degraded accordingly. In addition, since the time in which the substrates are placed in the atmosphere is generated depending on the order of loading, there is a problem that the characteristics of the processed organic functional layer are different for each substrate, and stable mass production cannot be performed.

  Therefore, in view of such circumstances, the present invention uniformly removes residual solvent and bake the organic functional layer when the organic functional layer is manufactured by a printing method, while reducing energy consumption as much as possible. Organic that enables space-saving by minimizing the installation area, reducing the processing time per substrate, and suppressing quality variation due to deterioration of the organic functional layer, enabling mass production. An object of the present invention is to provide a heating and drying apparatus for producing an organic EL that can produce a functional element.

  The invention according to claim 1 is provided with a substrate rack having a plurality of shelves capable of horizontally holding a substrate in a heating furnace, and the substrate held on the shelf of the substrate rack is heated by a hot air circulation system. In the heating and drying apparatus, a mechanism for replacing the inside of the heating furnace with an inert gas atmosphere, and a substrate carry-in / out section with respect to the heating furnace, provided in a plurality of stages corresponding to the shelves of each stage of the substrate rack, A multi-stage type load lock chamber capable of storing substrates one by one, and a mechanism capable of transporting and moving the substrate between each load lock chamber and each shelf of the substrate rack It is characterized by doing.

  According to a second aspect of the present invention, in the heating and drying apparatus according to the first aspect of the present invention, there is provided a mechanism for forcibly exhausting the gas in the load lock chamber to form a vacuum atmosphere.

  According to a third aspect of the present invention, in the heating and drying apparatus according to the first or second aspect of the present invention, the apparatus has a mechanism for exhausting positive pressure gas out of the load lock chamber while allowing an inert gas to flow into the load lock chamber. It is said.

  According to a fourth aspect of the present invention, in the heating and drying apparatus according to the second aspect of the present invention, the apparatus has a mechanism for causing the atmospheric gas in the heating furnace to flow into the load lock chamber.

  According to a fifth aspect of the present invention, in the heating and drying apparatus according to the fourth aspect, when the atmospheric gas in the heating furnace is caused to flow into the load lock chamber, the entire surface of the substrate disposed in the load lock chamber is evenly distributed. It has a mechanism for applying atmospheric gas.

  A sixth aspect of the present invention is the heating and drying apparatus according to any one of the first to fifth aspects, further comprising a cooling mechanism for cooling the load lock chamber.

  A seventh aspect of the invention is characterized in that in the heating and drying apparatus according to the sixth aspect of the invention, there is provided a heater that can uniformly heat the substrate disposed in the load lock chamber.

  According to the heating and drying apparatus of the present invention, the substrate carried into the load lock chamber is placed in a vacuum or in an inert gas atmosphere at room temperature, so that there is no fear of deterioration of device characteristics due to oxygen. Since it can be transported to a high-temperature heating furnace, the desired drying temperature can always be maintained in the heating furnace, and the temperature inside the heating furnace can be raised like a conventional heating / drying device using a multi-stage hot air circulation system. There is no need for cooling.

  In addition, since the load lock chamber, which is the substrate loading / unloading section, is provided in multiple stages corresponding to each shelf of the substrate rack in the heating furnace, it is necessary to wait for the substrates sequentially sent from the previous process. Instead, they can be sequentially carried into a heating and drying apparatus, heated for a predetermined time, and then sequentially carried out.

  Therefore, according to the heating and drying apparatus according to the present invention, it is possible to construct a mass production line capable of processing a substrate under continuous and stable heating and drying conditions with almost no stagnation time of the substrate. An organic EL having stable characteristics can be manufactured in a large amount at a low cost with a small amount of energy consumption.

The cross-sectional block diagram of the multistage heating drying apparatus which concerns on one Embodiment of this invention. The cross-sectional block diagram of the conventional multistage heating drying apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional configuration diagram schematically showing a heating and drying apparatus according to an embodiment of the present invention.

  This heating / drying apparatus includes a main body 1, and a rear portion in the main body 1 is a hot air circulation type heating furnace 2. In the heating furnace 2, a substrate rack 4 in which a plurality of horizontal shelves 3 are vertically installed in a plurality of stages is installed, and the substrate A can be held horizontally on each shelf 3.

  The hot air circulation type heating furnace 2 can be made relatively inexpensive in terms of both equipment cost and operation cost as compared with other types of heating furnaces. It is possible to simultaneously process a plurality of substrates A without providing a substrate transport mechanism that can be formed inside the heating furnace 2, and the heating temperature of the substrate A is the same as the atmospheric temperature in the furnace. There is an advantage that the temperature of the substrate A can be controlled by controlling the atmospheric temperature inside.

  However, when heat-treating the substrate A on which the organic functional layer is formed, there is a problem that when oxygen and water coexist at the time of heating, they cause a chemical reaction with the organic functional layer and deteriorate element characteristics. In particular, oxygen easily reacts with the double bond sites of π-electron molecules that are often used as functional materials. Therefore, when these organic functional layers are heated at high temperatures, they can be used in an inert gas atmosphere such as nitrogen or argon. It is necessary to do in.

  In view of this, the heating and drying apparatus is provided with a mechanism for replacing the inside of the heating furnace 2 with an inert gas atmosphere and circulates the inert gas heated by the heater during heating. Furthermore, it is desirable to provide a mechanism for constantly monitoring the oxygen concentration in the heating furnace 2 and supplying an inert gas into the heating furnace 2 in accordance with the numerical value of the oxygen concentration. In order to suppress the consumption of the inert gas, the inert gas in the heating furnace 2 is circulated through the oxygen filter and the solvent filter, and the exhaust gas passes through a pressurizing valve installed to keep the atmospheric pressure in the heating furnace 2 constant. It is more desirable to have a mechanism to perform.

  A multi-stage load lock chamber 5 that functions as a substrate carry-in / out portion for the heating furnace 2 is provided in the front portion of the main body 1. The load lock chamber 5 is provided in a plurality of stages so as to correspond to the shelves 3 of the substrate rack 4 in the heating furnace 2. That is, the same number of load lock chambers 5 as the shelves 3 of the substrate rack 4 are stacked on the top and bottom and provided on the front side of the substrate rack 4.

  Each load lock chamber 5 has slit-like substrate carry-in / out ports 6 a and 6 b through which the substrate A can pass, at the front and rear, respectively, and the front substrate carry-in / out port 6 a is outside the front side of the main body 1. The rear substrate carry-in / out port 6 b communicates with the heating furnace 2. Opening / closing shutters 7a and 7b are provided at the substrate loading / unloading ports 6a and 6b, respectively, and the interior of each load lock chamber 5 is hermetically sealed by closing the shutters 7a and 7b.

  The substrate A can be carried into each load lock chamber 5 by using the transfer robot 8. Each load lock chamber 5 is provided with a transfer arm 9 as a substrate transfer mechanism. The load lock chamber 5 has a minimum volume that can accommodate one substrate A and the transfer arm 9, and is provided with a mechanism for replacing the atmosphere with an inert gas atmosphere.

  The height of the bottom of each load lock chamber 5 is substantially the same as the height of the corresponding shelf 3 of the substrate rack 4, and the substrate A in the load lock chamber 5 can be moved from the load lock chamber 5 only by horizontal movement. It can be installed on the shelf 3 in the substrate rack 4 of the heating furnace 2.

  The multi-stage substrate rack 4 in the heating furnace 2 has no side walls, floors and top plates at each stage, is configured with only a minimum frame, and has a structure through which hot air circulating in the heating furnace 2 can easily pass. Each shelf 3 holds the end surface and back surface of the substrate A by point contact or line contact.

  As a means for transporting the substrate A, a conveyor type, a transport roll type, and the like are conceivable, but a drive unit that reduces the influence on the soaking accuracy of the substrate A as much as possible and can become a dust generation source in the heating furnace 2. In order to avoid placing, the transfer arm 9 is used that can hold the end surface and the back surface of the substrate A by point contact or line contact.

  This heating and drying apparatus is provided with a mechanism for replacing each load lock chamber 5 with an inert gas atmosphere. As this replacement mechanism, the following method can be adopted. That is, the substrate loading / unloading ports 6a and 6b are closed by shutters 7a and 7b, respectively, and the inside of the load lock chamber 5 is kept sealed from the outside air and the heating furnace 2, and in this state, the inside of the load lock chamber 5 is forced by a vacuum pump. By evacuating to a state close to vacuum and then using an inert gas supply means to make the inside of the load lock chamber 5 an inert gas atmosphere, or from a pressurizing valve while supplying an inert gas into the load lock chamber 5 There is a method in which the positive pressure gas in the load lock chamber 5 is exhausted to gradually lower the oxygen concentration.

  In addition, there is a method in which the shutter 7b of the substrate carry-in / out port 6b on the heating furnace 2 side is opened while the inside of the load lock chamber 5 is close to a vacuum. In the case of this method, it is conceivable that dust and the substrate A roll up in the load lock chamber 5 due to the momentum of the inert gas flowing into the load lock chamber 5 rapidly. Therefore, in this case, before opening the shutter 7b of the substrate carry-in / out port 6b, the inert gas atmosphere in the heating furnace 2 is gradually introduced into the load lock chamber 5 through a bypass pipe with a valve or the like.

  By the way, when the substrate A installed in the room temperature load lock chamber 5 is transported into the heating furnace 2, a temperature difference may occur in the traveling direction in the plane of the substrate A, and the in-plane characteristics may vary. . As a countermeasure in this case, an inert gas atmosphere in the heating furnace 2 is gradually introduced into the load lock chamber 5 through a bypass pipe with a valve or the like before the shutter 7b of the substrate carry-in / out port 6b of the load lock chamber 5 is opened. In the system, before the heated inert gas from the heating furnace 2 is evenly sprayed to the substrate A in the load lock chamber 5 and is carried into the heating furnace 2 by providing a rectifying plate or the like to control the air flow. The substrate A is preheated evenly.

  As another method for preheating the substrate A in the load lock chamber 5, there is a means for heating the substrate A by providing a heater in the load lock chamber 5. As the heater, a far-infrared panel heater or a hot plate that can uniformly heat the substrate A is suitable. However, when the substrate A is taken out from the heating furnace 2, it is necessary to lower the temperature in the load lock chamber 5 to at least about 50 ° C. or less, and therefore a mechanism for cooling the load lock chamber 5 may be provided. desirable.

  Further, when the substrate A taken out from the heating furnace 2 is carried out to the atmosphere at a high temperature, the element characteristics deteriorate due to oxidation. Therefore, the substrate A is once cut off from the heating furnace 2 in the load lock chamber 5 in the inert gas atmosphere, Allow to cool and then remove. At this time, a cooling mechanism for the load lock chamber 5 is provided, and the cooling mechanism is operated to shorten the cooling time of the substrate A. As a cooling mechanism, an air cooling method, a water cooling method, or the like can be used, but is not particularly limited thereto.

  Next, a specific example of the heat drying process performed using the heat drying apparatus will be described.

[Example 1]
First, a glass substrate A with a transparent electrode made of ITO was prepared, and an electron transport layer was formed on the glass substrate A in a pattern. Next, a solution obtained by dissolving a polyarylene vinylene polymer light emitter in a mixed solvent of 50% toluene and 50% diethylbenzene as a coating solution for the light emitting layer was applied onto the substrate A in a pattern by a printing method.

  Next, the glass substrate A on which the light emitting layer was printed was carried into the load lock chamber 5 of the heating and drying apparatus according to the present invention from the substrate carry-in / out entrance 6a using the carrying robot 8. At this time, the substrate loading / unloading port 6b of the load lock chamber 5 is closed by the shutter 7b. After loading the glass substrate A, the substrate loading / unloading port 6a of the load lock chamber 5 is closed by the shutter 7a, the load lock chamber 5 is shut off from the outside air, and further, the load lock is applied from the pressurizing valve while flowing in nitrogen gas as an inert gas. The other gas components in the chamber 5 were exhausted, and the load lock chamber 5 was filled with a nitrogen gas atmosphere in about 2 minutes. At this time, the oxygen concentration in the load lock chamber 5 was 100 ppm or less.

  Next, the shutter 7b of the substrate loading / unloading port 6b between the load lock chamber 5 carrying the glass substrate A and the heating furnace 2 is opened, and the glass substrate A in the load lock chamber 5 is moved into the heating furnace 2 using the transfer arm 9. Were placed on the shelf 3 at a position corresponding to the load lock chamber 5. At this time, the inside of the heating furnace 2 was a nitrogen gas atmosphere with an oxygen concentration of 100 ppm or less, the furnace temperature was maintained at 200 ° C., and the glass substrate A carried in was heated to 200 ° C. in about 5 minutes.

  Thereafter, the glass substrate A was held at a temperature of 200 ° C. for 10 minutes in the heating furnace 2 and then returned to the load lock chamber 5 to close the substrate carry-in / out port 6b with the shutter 7b. The glass substrate A returned to the load lock chamber 5 was cooled to 50 ° C. or less in about 5 minutes, and then the shutter 7a of the substrate carry-in / out port 6a was opened and carried out from the heat drying apparatus.

  The heating and drying process from the time when the glass substrate A so far was carried into the heat drying apparatus to the time when it was carried out took about 22 minutes. At this time, if the heating and drying apparatus is a multi-stage furnace having, for example, 11 or more stages, one glass substrate A can be sequentially carried into the heating and drying apparatus every 2 minutes.

  After the heating and drying step, lithium and aluminum were deposited on the substrate A on which the light emitting layer was formed by a vacuum deposition method to a thickness of 0.5 nm and 200 nm, respectively, to obtain an organic EL element.

  The characteristics of mass-produced organic EL elements were evaluated by randomly extracting a plurality of substrates, and no deterioration of the characteristics was observed in any of the organic EL elements.

[Comparative example]
Next, as a comparative example, a heating and drying process performed using the conventional hot air circulation type multi-stage heating and drying apparatus shown in FIG. 2 will be described.

  A polyarylene vinylene polymer light emitter is dissolved in a mixed solvent of 50% toluene and 50% diethylbenzene on a glass substrate A on which a transparent electrode made of ITO and an electron transport layer are formed in a pattern, as a coating solution for the light emitting layer. The dissolved solution was applied in a pattern by a printing method.

  The glass substrate A on which the light emitting layer was formed was placed on the shelf 15 of the substrate rack 16 in the heating furnace 12 through the opening 13 from the transfer robot 17. The substrate rack 16 is provided with, for example, 15 levels of shelves 15, and the glass substrates A sent from the light emitting layer printing process are installed on all the shelves 15 of the 15 levels of the substrate rack 16. The installation took 30 minutes.

  Next, the shutter 14 of the heating furnace 12 is closed, the inside of the heating furnace 12 is shut off from the outside air, the gas component in the heating furnace 12 is exhausted from the pressurizing valve while flowing in nitrogen gas, and the heating is performed for about 20 minutes. The inside of the furnace 12 was an inert gas atmosphere. At this time, the oxygen concentration in the heating furnace 12 was 100 ppm or less.

  Thereafter, the nitrogen gas circulating in the heating furnace 12 was heated, and the ambient temperature in the heating furnace 12 was gradually raised. When the temperature was rapidly increased, a temperature difference was generated in the plane of the glass substrate A and between the glass substrates A. Therefore, the temperature was raised from room temperature to 200 ° C. over a period of 40 minutes. At this time, the temperature of the glass substrate A installed in the heating furnace 12 rose to 200 ° C. together with the atmospheric temperature in the heating furnace 12.

  Then, after holding the glass substrate A in the heating furnace 12 at 200 ° C. for 10 minutes, heating of the nitrogen gas circulating in the heating furnace 12 is stopped, and normal temperature nitrogen gas is supplied into the furnace. The atmosphere temperature in 12 was lowered. It took about 40 minutes for the atmospheric temperature in the heating furnace 12 and the temperature of the glass substrate A to reach 50 ° C. or lower.

  Thereafter, the shutter 14 of the heating furnace 12 was opened, and the glass substrate A was carried out from each shelf 15 of the substrate rack 16 in the heating furnace 12 by the transfer robot 17.

  It took about 2 hours and 20 minutes for the heating and drying process from the time when the glass substrate A so far was carried into the heating and drying apparatus to the time when the glass substrate A was carried out. Since there were 15 glass substrates A subjected to the heat drying treatment, the tact time was 9 minutes or more per sheet. In order to heat-dry the glass substrate A after the light emitting layer printing every two minutes, five heating / drying apparatuses capable of carrying 15 sheets are required.

  After the heating and drying step, lithium and aluminum were deposited on the substrate A on which the light emitting layer was formed by a vacuum deposition method to a thickness of 0.5 nm and 200 nm, respectively, to obtain an organic EL element.

  The characteristics of mass-produced organic EL elements were evaluated by randomly extracting a plurality of substrates. As a result, variation in characteristics was observed for each organic EL element, and the current efficiency was degraded by about 5% at the maximum. confirmed.

[Example 2]
Next, another specific example of the heat drying process performed using the heat drying apparatus of the present invention will be described. In the heating and drying apparatus in this case, the heating furnace 2 and the load lock chamber 5 are connected by a bypass pipe with a valve, and a water cooling tube for cooling the load lock chamber 5 is installed on the wall surface of the load lock chamber 5. Has been.

  First, a glass substrate A with a transparent electrode made of ITO was prepared, and an electron transport layer was formed on the glass substrate A in a pattern. Next, a solution obtained by dissolving a polyarylene vinylene polymer light emitter in a mixed solvent of 50% toluene and 50% diethylbenzene as a coating solution for the light emitting layer was applied onto the substrate A in a pattern by a printing method.

  Next, the glass substrate A on which the light emitting layer was printed was carried into the load lock chamber 5 from the substrate carry-in / out entrance 6a using the transfer robot 8. At this time, the substrate loading / unloading port 6b of the load lock chamber 5 is closed by the shutter 7b. After loading the glass substrate A, the substrate loading / unloading port 6a of the load lock chamber 5 is closed with a shutter 7a, the load lock chamber 5 is shut off from the outside air and sealed, and the gas components in the load lock chamber 5 are vacuum pumped in this state. The load lock chamber 5 was almost evacuated in about 2 minutes. At this time, the atmospheric pressure in the load lock chamber 5 was 100 Pa or less.

  Thereafter, the bypass pipe valve connecting the heating furnace 2 and the load lock chamber 5 was opened. The inside of the heating furnace 2 is always a nitrogen gas atmosphere having an oxygen concentration of 100 ppm or less, and the furnace temperature is maintained at 200 ° C. The nitrogen gas heated to 200 ° C. in the heating furnace 2 is in the load lock chamber 5. Was drawn into. At this time, the nitrogen gas at 200 ° C. drawn into the load lock chamber 5 sprayed almost uniformly on the entire surface of the glass substrate A by the shape of the outlet of the bypass pipe and the wind direction plate. Then, in the time of about 5 minutes, the inside of the load lock chamber 5 became a nitrogen gas atmosphere with an oxygen concentration of 100 ppm or less, and the glass substrate A could be heated to a temperature of about 200 ° C.

  Next, the shutter 7b of the substrate loading / unloading port 6b between the load lock chamber 5 carrying the glass substrate A and the heating furnace 2 is opened, and the substrate A in the load lock chamber 5 is transferred into the heating furnace 2 using the transfer arm 9. And placed on the shelf 3 of the substrate rack 4. Thereafter, the substrate carry-in / out port 6b between the load lock chamber 5 and the heating furnace 2 was closed by the shutter 7b. In addition, a water cooling pipe installed on the wall surface of the load lock chamber 5 was operated. In response to this, the nitrogen gas atmosphere in the load lock chamber 5 was rapidly cooled to 50 ° C. or less by a water-cooled tube within 10 minutes.

  Next, the glass substrate A held for 10 minutes at a temperature of 200 ° C. in the heating furnace 2 was returned to the load lock chamber 5 and the substrate carry-in / out port 6b was closed by the shutter 7b. The glass substrate A returned to the load lock chamber 5 was cooled to 50 ° C. or less in about 5 minutes. Thereafter, the shutter 7a of the substrate carry-in / out port 6a was opened, and the substrate A was carried out of the load lock chamber 5.

  It took about 22 minutes to heat and dry the glass substrate A so far until the glass substrate A was carried into the heat drying apparatus and then carried out. At this time, if the substrate rack 4 of the heating / drying apparatus is a multistage system having 11 or more stages, one glass substrate A can be sequentially carried into the heating / drying apparatus every two minutes.

  In addition, with this heating and drying apparatus, the substrate A is baked at a desired temperature within ± 3 ° C. when the temperature variation within the substrate surface is within 5 ° C. even when the temperature is raised to 200 ° C. Can be done.

  After the heating and drying step, lithium and aluminum were deposited on the substrate A on which the light emitting layer was formed by a vacuum deposition method to a thickness of 0.5 nm and 200 nm, respectively, to obtain an organic EL element.

  The characteristics of mass-produced organic EL elements were evaluated by randomly extracting a plurality of substrates, and no deterioration of the characteristics was observed in any of the organic EL elements.

  The present invention relates to an apparatus for heat-treating an organic film coated on a substrate, and more particularly to a heat-drying apparatus for producing an organic EL including a drying process.

  By using the heating and drying apparatus according to the present invention, the baking of the organic functional layer formed on the substrate is performed with high soaking accuracy and with a minimum floor area, while reducing energy consumption as much as possible, and high throughput. Accordingly, it is possible to manufacture an organic EL element having always stable characteristics.

A ... Substrate 1 ... Main body 2 ... Heating furnace 3 ... Shelf 4 ... Substrate rack 5 ... Load lock chamber 6a. 6b .. substrate loading / unloading port 7a. 7b ... Shutter 8 ... Transfer robot 9 ... Transfer arm

Claims (7)

In a heating and drying apparatus that includes a substrate rack having a plurality of shelves capable of horizontally holding a substrate in a heating furnace, and heat-treats the substrate held on the shelf of the substrate rack by a hot air circulation method,
A mechanism for replacing the inside of the heating furnace with an inert gas atmosphere;
A substrate loading / unloading unit with respect to the heating furnace, provided in a plurality of stages corresponding to the shelves of each stage of the substrate rack, and a multi-stage type load lock chamber capable of storing substrates one by one,
A mechanism capable of transporting and moving a substrate between each load lock chamber and each shelf of the substrate rack;
A heating and drying apparatus for producing an organic EL, comprising:   The heating and drying apparatus for manufacturing an organic EL according to claim 1, further comprising a mechanism for forcibly exhausting the gas in the load lock chamber to form a vacuum atmosphere.   The heating and drying apparatus for manufacturing an organic EL according to claim 1 or 2, further comprising a mechanism for exhausting a positive pressure gas outside the load lock chamber while allowing an inert gas to flow into the load lock chamber.   The heating / drying apparatus for manufacturing an organic EL according to claim 2, further comprising a mechanism for causing the atmospheric gas in the heating furnace to flow into the load lock chamber.   5. The apparatus according to claim 4, further comprising a mechanism that uniformly applies the atmospheric gas to the entire surface of the substrate disposed in the load lock chamber when the atmospheric gas in the heating furnace flows into the load lock chamber. Heat drying apparatus for organic EL production.   The heating / drying apparatus for manufacturing an organic EL according to claim 1, further comprising a cooling mechanism for cooling the load lock chamber.   The heating / drying apparatus for manufacturing an organic EL according to claim 6, further comprising a heater that can uniformly heat the substrate disposed in the load lock chamber.

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