JP2007005056A - Organic el device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device which suppresses occurrence of luminance unevenness, color unevenness or the like due to variations in the film thickness of a functional layer, and also to provide its manufacturing method. <P>SOLUTION: The manufacturing method comprises steps of: forming a pixel electrode 108 on a substrate 102; forming a barrier rib 10 surrounding the pixel electrode 108, with one side surface having an affinity for water and at least with one part of upper surface having water repellency, over the substrate 102 where the pixel electrode 108 is formed; forming the functional layer 126 including at least a light emitting layer 124 on the pixel electrode 108 surrounded by the barrier rib 10, by dropping a liquid material to remove solvent; and forming a cathode layer 128 over the substrate 102 where the functional layer 126 is formed. As a result, variations in the film thickness of the functional layer is hard to occur, so the occurrence of color unevenness, luminance unevenness or the like is suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic EL device and a manufacturing method thereof.

  In recent years, EL (electroluminescence) devices have been applied to various display devices as self-luminous displays that replace liquid crystal displays. Further, development is progressing as a light source for printer heads. In general, an organic EL (electroluminescence) device generally includes an individually controllable electrode (hereinafter referred to as a pixel electrode) and an electrode (hereinafter referred to as a cathode) that has a common potential between all the pixels opposed to the electrode. It is composed of a solid thin film layer (hereinafter referred to as a functional layer) including at least an organic EL layer (hereinafter referred to as a light emitting layer) sandwiched between the two electrodes.

  In the display device, when a voltage is applied between the electrodes and a current flows through the functional layer, the light emitting layer emits light, and characters, images, and the like are displayed in the display area of the organic EL device. The organic EL device is roughly classified into a low molecular type and a high molecular type depending on the material constituting the organic EL layer to be used. For example, as a method for forming a functional layer in a manufacturing process of a polymer organic EL device, a material constituting the functional layer is dissolved in a solvent on a pixel electrode surrounded by a partition made of a liquid repellent organic material. A method of dropping a dispersed liquid material (hereinafter referred to as a liquid material) with an ink jet apparatus and then removing the solvent in a drying step (hereinafter referred to as an ink jet method) has been proposed. The reason for making the partition surface liquid repellent is to prevent the dropped liquid material from flowing out onto the adjacent pixel electrode. The ink-jet method has advantages such as that a process can be shortened because thin film formation and patterning can be performed simultaneously, and that a waste of material is reduced because a liquid material is supplied directly onto the pixel electrode.

However, when a functional layer is formed by an inkjet method on a pixel electrode whose entire surface is surrounded by a liquid-repellent partition wall, only the pixel electrode is lyophilic so that the partition wall and the pixel electrode are in contact with each other. The film thickness of the functional layer becomes extremely thin, which may cause a short circuit between the electrodes in contact with both surfaces of the functional layer. Therefore, in order to avoid the above short circuit, for example, in Patent Document 1, a silicon oxide film is sandwiched between an organic material partition wall to which liquid repellency has been added by treatment with CF ₄ plasma and a pixel electrode, thereby providing liquid repellency. An organic EL device having a structure in which a portion where an organic material partition wall provided with a pixel electrode is in contact is eliminated. Since the silicon oxide film is lyophilic, there is no portion where the functional layer is extremely thin on the pixel electrode, and the above-described short circuit between the electrodes on both sides of the functional layer can be prevented.

Japanese Patent Application Laid-Open No. 2001-291583

  However, when a functional layer is formed on the pixel electrode surrounded by the partition wall having the above structure by an inkjet method, the thickness of the functional layer may vary within one pixel, that is, the thickness uniformity may deteriorate. It turns out. The reason is that the boundary region between the organic material portion having liquid repellency of the partition wall and the silicon oxide film having lyophilicity is a stage where the drying proceeds and cures, particularly during the period from drying to curing. It has been empirically found that this is because it adversely affects the surface condition of the liquid material. The variation in the thickness of the functional layer can cause color unevenness, luminance unevenness, and the like due to variations in current density in the functional layer.

  Therefore, an object of the present invention is to provide an organic EL device with little variation in the functional layer thickness and a method for manufacturing the same.

  In order to achieve the above object, an organic EL device manufacturing method according to the present invention includes a step of forming a pixel electrode on a substrate, and at least a part of a surface having liquid repellency so as to surround the pixel electrode. And a step of forming a partition wall in which another part of the surface is lyophilic, and a step of forming a functional layer including at least a light emitting layer by dripping and drying a liquid material on the pixel electrode; And forming a cathode layer on the substrate on which the functional layer is formed.

  According to this manufacturing method, the liquid material dropped by the liquid-repellent portion of the upper surface of the partition wall is adjacent to the partition wall while suppressing the occurrence of variations in the film thickness of the functional layer by the lyophilic side surface of the partition wall. It is possible to avoid outflow onto the pixel electrode.

  Preferably, the step of forming the partition includes a step of forming an organic material layer on the entire surface of the substrate and patterning the organic material layer.

  While organic materials are inherently lyophilic, the surface can be made liquid-repellent by fluorine-based plasma treatment. Therefore, according to such a manufacturing method, the upper surface is liquid-repellent and the side surface is lyophilic. The partition which has property can be formed easily.

  Preferably, the step of forming the partition wall is performed by subjecting the surface of the organic material layer to plasma treatment under a condition that makes the liquid repellency higher before patterning the organic material layer. including.

  According to such a manufacturing method, while the upper surface has liquid repellency while being formed of only an organic material, the side surface in contact with the functional layer can form a lyophilic partition wall, so that the configuration of the partition wall is not complicated. Furthermore, the occurrence of variations in the film thickness of the functional layer can be suppressed.

  Preferably, the step of forming the partition wall includes plasma treatment under conditions such that at least a part of the upper surface of the partition wall has higher liquid repellency after the organic material layer is patterned to form the partition wall. The process performed by giving is included.

  According to such a manufacturing method, liquid repellency can be imparted only to the upper surface of the partition wall formed of only an organic material, while the lyophilicity of the side surface of the partition wall in contact with the functional layer can be maintained. The occurrence of variations in the film thickness of the functional layer can be suppressed without increasing the complexity.

  Preferably, the method includes a step of performing oxygen plasma treatment on the substrate after forming the partition and before forming the functional layer.

  Since oxygen plasma can remove organic residues generated during patterning, according to this manufacturing method, the side surfaces of the partition walls and the surface of the pixel electrodes can be made more lyophilic, and the functional layer Occurrence of variations in film thickness can be further suppressed.

  In order to achieve the above object, an organic EL device manufacturing method according to the present invention includes a step of forming a pixel electrode on a substrate, a top layer made of at least an organic material around the pixel electrode, A step of forming a partition made of a plurality of layers including a lowermost layer made of an inorganic material, a step of performing a treatment such that a part or the whole of the surface of the organic material layer becomes liquid repellent, and the pixel A step of forming a functional layer including at least a light emitting layer by dropping and drying a liquid material on the electrode; and a step of forming a cathode layer on the substrate on which the functional layer is formed, and The inorganic material layer is formed to be thicker than the functional layer.

  According to such a manufacturing method, the functional layer can eliminate a portion in contact with the liquid-repellent portion of the partition wall, and a boundary region between the liquid-repellent portion and the lyophilic portion of the partition wall Occurrence of variations in the thickness of the functional layer due to the above can be suppressed.

  Preferably, the inorganic material layer is formed thicker than the liquid level of the liquid material immediately after dropping.

  According to this manufacturing method, even during the drying of the functional layer, the surface of the partition wall does not come into contact with the liquid repellent portion, and the occurrence of variations in the thickness of the functional layer is further suppressed. Can do.

  Preferably, the inorganic material layer is formed thicker than the organic material layer.

  According to this manufacturing method, the height of the partition wall is not increased more than necessary, and the step on the substrate surface after the functional layer is formed can be reduced. Therefore, the cathode layer formed on the functional layer is attached. You can improve your surroundings.

  Preferably, the partition walls are formed by patterning the plurality of layers at once.

  According to this manufacturing method, the manufacturing process of the organic EL device having a multi-layered partition wall can be simplified, and the manufacturing cost can be reduced.

  Preferably, the partition wall composed of the plurality of layers is formed by patterning at least one layer before forming a layer thereon.

  According to this manufacturing method, the pattern dimension of the upper layer of the partition can be made smaller than the pattern dimension of the lower layer, and the side shape of the partition can be prevented from overhanging. As a result, the throwing power of the cathode layer formed on the functional layer can be improved.

  Preferably, an oxygen plasma treatment is performed on the entire surface of the substrate after forming the partition and before forming the functional layer.

  According to this manufacturing method, the side surface portion of the inorganic material layer that comes into contact with the functional layer and the surface of the pixel electrode become lyophilic, and variations in the thickness of the functional layer can be further suppressed.

  In order to achieve the above object, an organic EL device according to the present invention includes a pixel electrode disposed on a substrate, a partition wall surrounding the pixel electrode, a functional layer including at least a light emitting layer, and the functional layer. A counter electrode facing the pixel electrode, wherein at least a part of the surface of the partition wall has a liquid repellent surface, and at least a part of the surface of the partition wall in contact with the functional layer is Has a lyophilic surface.

  With this configuration, when the functional layer is formed, the liquid material is prevented from flowing out onto the adjacent pixel electrode by the portion having the liquid repellent surface on the upper surface of the partition wall, and the lyophilic surface on the side surface of the partition wall is prevented. Owing to the portion, the occurrence of variations in the thickness of the functional layer can be suppressed, and uneven color caused by the variations in thickness can be suppressed.

  Preferably, the partition is formed of a plurality of layers including at least an uppermost layer and a lowermost layer.

  With this configuration, the partition wall can be formed of different materials such as a layer made of an organic material and a layer made of an inorganic material. And while the organic material can make the surface lyophobic by plasma treatment, since the original property is lyophilic, it prevents the outflow of the liquid material onto the adjacent pixel electrode when forming the functional layer, and It is possible to simultaneously suppress the occurrence of variations in the thickness of the functional layer.

  In order to achieve the above object, an organic EL device according to the present invention includes a pixel electrode disposed on a substrate, a partition wall surrounding the pixel electrode, a functional layer including at least a light emitting layer, and the functional layer. A surface of the uppermost layer having liquid repellency, a surface of the lowermost layer having lyophilicity, and a film of the lowermost layer The thickness is larger than the film thickness of the functional layer.

  With this configuration, the functional layer comes into contact only with the lowermost layer of the partition wall whose surface is lyophilic. Therefore, the uppermost layer of the partition wall having a liquid repellent surface prevents the liquid material from flowing out onto the adjacent pixel electrode, and the functional layer does not touch the uppermost layer having the liquid repellent property. The occurrence of variations in the thickness of the functional layer can be suppressed.

(Summary of Invention)
1 to 5 are sectional views of an organic EL device before completion, showing an outline of the present invention, and illustrate a pixel electrode, a functional layer, and the like. A TFT 104 controlled by the gate electrode 103 is formed on the substrate 102, and a pixel that is electrically connected to the TFT 104 via a contact hole 106 formed at a predetermined position of a silicon oxide film 105 as an interlayer insulating film. An electrode 108 is formed.

  FIG. 1 shows a partition wall 10 formed of a single layer made of only an organic material and having a liquid repellent portion 11 on its upper surface, and a functional layer formed in the partition wall. Since there is no boundary region between the organic material portion and the silicon oxide film portion in the partition wall, a functional layer with good film thickness uniformity can be obtained.

  FIG. 2 shows an organic EL device having a two-layer partition 30 formed of a partition upper part 306 made of an organic material and a partition lower part 304 made of an inorganic material. The partition upper portion 306 is liquid-repellent treated not only on the upper surface but also on the side surface. And the aspect immediately after a functional layer material (liquid material) is dripped is shown with the broken line, and the aspect when it becomes solid by drying and hardening is shown with the continuous line. As described above, in the thin film formation by the ink jet method, the volume of the material changes greatly during the transition from the liquid to the solid. Therefore, in order to avoid the influence of the boundary described above, one having more lyophilic portions in the partition wall Is preferred. Therefore, it is also conceivable that the side surface (at least a part of) of the partition upper portion 306 is made lyophilic even in a two-layer partition.

  3 to 5 are organic EL devices having a two-layer partition wall 30 similar to the organic EL device shown in FIG. 2, and the ratio of the portion 11 subjected to the liquid repellent treatment on the surface of the partition upper portion 306 is changed. It has been made. As shown in FIG. 3, if the entire surface of the partition upper portion 306 is subjected to a liquid repellent treatment, the functional layer cannot be formed thicker than the partition lower portion 304. As shown in FIG. 4, if a part of the side surface (continuous from the upper surface) of the partition upper portion 306 is subjected to the liquid repellent treatment, a thicker functional layer can be formed. Further, as shown in FIG. The entire side surface can be made lyophilic and the functional layer can be thickened accordingly.

  However, if it is better that the functional layer material during drying / curing, that is, liquid, does not contact the boundary region as much as possible, the thickness of the partition wall lower portion 304 is made to be more lyophilic than the side surface of the partition upper portion 306 is made lyophilic. It is preferable to increase. Therefore, from the viewpoint of the uniformity (surface shape) of the functional layer, a single material partition wall having a lyophilic side surface and a liquid repellent treatment on the upper surface, or an organic material partition wall upper part and at least a cured functional layer film It can be said that a two-layer partition wall composed of a partition wall lower part 304 made of an inorganic material thicker than the thickness is preferable. Based on such a viewpoint, the present invention provides an organic EL device having a functional layer having a good surface shape with improved film thickness uniformity.

  In each of the first to fifth embodiments described below, a so-called bottom emission type organic EL device that takes out light from the back surface of the substrate (the surface on which TFTs, pixel electrodes, etc. are not formed) is taken as an example. However, the present invention is not limited to this, and for example, a so-called top emission type organic EL that extracts light from the surface of the substrate (the surface on which TFTs, pixel electrodes, etc. are formed). The same applies to the device. Moreover, although this embodiment demonstrated along the example using the functional layer containing 2 layers of a positive hole injection layer and a light emitting layer, you may include another layer.

(First embodiment)
FIGS. 6-14 shows 1st Embodiment of the manufacturing method of the organic electroluminescent apparatus concerning this invention. First, as shown in FIG. 6, a thin film transistor (hereinafter referred to as TFT) 104 as a switching element including a gate electrode 103 is formed on a transparent substrate (hereinafter referred to as substrate) 102, and ( A silicon oxide film 105 as an interlayer insulating film is formed on the entire surface of the substrate. Then, a contact hole 106 is formed by selectively removing the silicon oxide film 105 at a predetermined position on the TFT 104, and the pixel electrode 108 that is electrically connected to the TFT 104 through the contact hole 106 is made of ITO (indium tin oxide alloy). Form with. Further, a polyimide film 110 is formed as an organic material layer on the entire surface of the substrate.

Next, as shown in FIG. 7, the polyimide film 110 formed on the entire surface of the substrate 102 is subjected to plasma treatment with CF ₄ plasma A. By the above treatment, fluorine atoms enter the upper surface portion 111 of the polyimide film 110 and react with the carbon atoms contained in the polyimide, so that the surface becomes liquid repellent. The gas used for the plasma treatment is not limited to CF ₄ , and other fluorine-containing gases such as SF ₆ and CHF ₃ may be used.

  Next, as shown in FIG. 8, the polyimide film 110 on the pixel electrode 108 is selectively removed by photolithography to expose the pixel electrode 108. Here, in practice, the pixel electrode 108 and the polyimide film 110 are removed so that a part where the pixel electrode 108 and the polyimide film 110 are slightly overlapped is formed in the outer peripheral part of the pixel electrode 108. Then, the pixel electrode 108 has a shape surrounded by the partition 10 formed by patterning the polyimide film 110. In the previous step, the upper surface portion 111 of the polyimide film is subjected to a liquid repellent treatment, and then the partition wall shape is formed by photolithography. Therefore, the partition wall 10 is formed by patterning the upper surface portion 111 of the polyimide film. Only the liquid repellency is maintained, and the side wall 14 of the partition remains the original property (lyophilicity) of the polyimide.

  The polyimide film 110 may be formed of photosensitive polyimide (which is common to all the first to fifth embodiments). This is because the steps of applying and removing the photoresist can be omitted.

  Next, as shown in FIG. 9, plasma treatment is performed on the entire surface of the substrate 102 with oxygen plasma B to remove organic residues remaining on the substrate 102, particularly on the pixel electrode 108, when the polyimide film 110 is patterned. To do. As a result of the oxygen plasma treatment, the original properties (lyophilicity) of the pixel electrode 108 are restored.

Here, since the upper surface 12 of the partition wall is made of a stable substance such as Teflon (registered trademark) by the CF ₄ plasma treatment, the liquid repellency is maintained even after the oxygen plasma treatment by optimizing the conditions. be able to.

  Next, as illustrated in FIG. 10, a liquid material C obtained by dissolving or dispersing a material constituting the hole injection layer in a solvent is dropped onto the pixel electrode 108 from the nozzle 120 of the ink jet apparatus. As a material constituting the hole injection layer, for example, a polythiophene derivative or a polyaniline derivative is used. Here, the nozzle 120 of the ink jet apparatus is adjusted so that the liquid material C is dropped onto the center of the pixel electrode 108 as shown in the figure, but there may be some deviation. Further, the liquid material C is not always dropped directly below. However, even if the liquid material C is applied to the partition wall 10 for the reasons described above, the partition wall upper surface 12 has liquid repellency, so that the liquid material is not dripped beyond the intermediate line between pixels. C flows onto the predetermined pixel electrode 108.

  Even when the volume of the liquid material C dropped is larger than the volume of the depression formed by the partition wall 10 and the pixel electrode 108, the partition upper surface 12 has liquid repellency as described above, so that the liquid crystal C is dropped. The liquid material C swells due to surface tension and does not flow out onto adjacent pixels.

  Next, as shown in FIG. 11, the solvent is removed by a drying / curing process to form a hole injection layer 122 on the pixel electrode 108.

  Next, as shown in FIG. 12, a liquid material D obtained by dissolving or dispersing a material constituting the organic EL layer in a solvent from the nozzle 120 of the ink jet device onto the pixel electrode 108 (on the hole injection layer 122). Is dripped. Since the partition wall upper surface 12 has liquid repellency, it can be avoided that the liquid material D flows out onto the adjacent pixels as in the case of the liquid material C described above.

  Next, as shown in FIG. 13, the solvent is removed by a drying / curing process to form a light emitting layer 124 on the pixel electrode 108. A functional layer 126 is formed by the hole injection layer 122 and the light emitting layer 124.

  In addition, although it is common to all the embodiments according to the present invention, the combination of the liquid material dropping process of FIGS. 10 and 12 and the drying / curing process of FIGS. 11 and 13 is limited to the above two times. Is not to be done. This is because the functional layer 126 may further include an electron transport layer and the like.

  Finally, as shown in FIG. 14, a cathode layer 128 is formed on the entire surface of the substrate 102. In the case of a so-called bottom emission method in which light is extracted from the back side of the substrate 102, the light source is formed of one or a plurality of layers made of a metal film (aluminum, aluminum alloy, silver, or silver alloy) having light reflectivity. On the other hand, in the case of a so-called top emission method in which light is extracted from the front side of the substrate 102, the cathode layer is formed of ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) which is a light-transmitting conductive film. Is done. Then, after some subsequent well-known steps, the organic EL device is completed.

  As described above, in the process of creating the functional layer, if the liquid material containing the material constituting the organic EL layer is in contact with the partition wall of the liquid repellent surface, the influence extends to the center of the pixel electrode, and drying / curing Variations in the film thickness of the subsequent functional layer can occur, resulting in a wavy cross-sectional shape. However, since the partition wall side face 14 can be made lyophilic while maintaining the liquid repellency of the partition upper surface 12 by performing the above manufacturing method, variations in the film thickness of the functional layer 126 can be suppressed. Furthermore, since the drying / curing process is performed in a state where the liquid materials C and D are attracted to the lyophilic partition wall 14, the formed functional layer 126 tends to be thick at the peripheral portion and thin at the central portion. become. Therefore, even when the liquid materials C and D are dropped using the ink jet method and the functional layer 126 is formed by drying and curing, color unevenness due to variations in current density in the functional layer 126, particularly in the light emitting layer, It is possible to obtain an organic EL device in which a decrease in lifetime is suppressed.

(Second Embodiment)
15 to 18 show a second embodiment of a method for manufacturing an organic EL device according to the present invention. In addition, in each figure, the same code | symbol is attached | subjected to the component which is common in FIGS. 6-14.

  First, as shown in FIG. 15, the TFT 104 as the switching element including the gate electrode 103, the contact hole 106, the pixel electrode 108, and the like are formed on the substrate 102 as in the first embodiment, and then the organic material layer is formed. A polyimide film 110 is formed.

  Next, as shown in FIG. 16, the polyimide film 110 on the pixel electrode 108 is selectively removed by photolithography to expose the pixel electrode 108, and the partition 10 is formed in the remaining portion. At that time, similarly to the first embodiment, the pixel electrode 108 and the polyimide film 110 are removed so that a part where the pixel electrode 108 and the polyimide film 110 are slightly overlapped with each other. Further, the polyimide film 110 is preferably formed of photosensitive polyimide as in the first embodiment.

  Through the above process, the pixel electrode 108 has a shape surrounded by the partition wall 10 made of polyimide. That is, a depression is formed whose side wall is a polyimide partition wall 10 and whose bottom surface is a pixel electrode 108.

Next, as shown in FIG. 17, the selective plasma mask 20 in which the partition wall portions are punched is overlaid on the substrate 102. As in the first embodiment, plasma processing is performed with plasma A using a gas containing fluorine atoms, such as CF ₄ . The plasma A does not reach the side wall 14 due to the selective plasma mask 20.

By this process, as shown in FIG. 18, only the portion 22 (at least a part of the upper surface of the partition wall 10) that is not covered with the mask becomes liquid repellent. On the other hand, the other part, that is, mainly the side surface 14 of the partition wall (and the upper surface of the pixel electrode 108) is not subjected to the fluorination treatment, and the original property is maintained. Note that the gas used for the plasma treatment is not limited to CF ₄ , and other fluorine-containing gas such as SF ₆ or CHF ₃ may be used.

  Thereafter, as in the first embodiment, the entire surface of the substrate is subjected to plasma treatment with oxygen plasma. The organic residue on the side wall 14 and the pixel electrode 108 can be removed while maintaining the liquid repellency of the portion 22 not covered with the mask of the partition 10.

  Therefore, up to the above-described steps, the lyophilic pixel electrodes 108 arranged in a matrix on the substrate 102 and the periphery surrounding at least a part of the upper surface having liquid repellency and the side surfaces being parent. A liquid partition 10 can be formed.

  Thereafter, a functional layer 126 including a hole injection layer 122 and a light emitting layer 124 is formed on the pixel electrode 108 and a cathode layer 128 is formed on the entire surface of the pixel electrode 108 by the same process as in FIGS. Further, a few well-known processes are added to complete the organic EL device.

  Since at least a part of the partition upper surface 12 has liquid repellency, the liquid material C and D that are dropped can be prevented from flowing out onto adjacent pixels, as in the first embodiment. .

  Similarly to the first embodiment, in this embodiment, the partition wall 10 is formed of a single material (polyimide film 110), and at least a part of the upper surface 12 has liquid repellency and the side surface 14 has lyophilicity. Can be obtained. The liquid material that has been dropped can be prevented from flowing out to adjacent pixels on the upper surface of the partition wall having liquid repellency, while the functional layer after drying / curing has the side surface of the partition wall and the pixel electrode having lyophilicity. It will be in contact only with. Therefore, even when the liquid material is dropped by an ink jet method and the functional layer 126 is formed by drying and curing, the occurrence of variations in the film thickness of the functional layer 126 can be suppressed. As a result, it is possible to obtain an organic EL device in which color unevenness, luminance unevenness, lifetime reduction, and the like due to the above variation are suppressed.

(Third embodiment)
19 to 29 show a third embodiment of the method for manufacturing an organic EL device according to the present invention. In each figure, the same code | symbol is attached | subjected to the component which is common in FIGS. 6-14.

  First, as shown in FIG. 19, a TFT 104 as a switching element including a gate electrode 103 is formed on a substrate 102, and a silicon oxide film 105 as an interlayer insulating film is formed on the upper surface (over the entire surface of the substrate). Then, a contact hole 106 is formed at a predetermined position on the TFT 104, and a pixel electrode 108 that is electrically connected to the TFT 104 through the contact hole 106 is formed. Since the pixel electrode 108 needs transparency and conductivity, ITO is used. Further, a second silicon oxide film 302 is formed as an inorganic material layer on the entire surface of the substrate.

  Here, the film thickness of the second silicon oxide film 302 is formed to be larger than the film thickness of the functional layer 126 (see FIG. 28) formed on the pixel electrode 108 in the subsequent process. Since the second silicon oxide film 302 is lyophilic with respect to the liquid material containing the material constituting the functional layer, the edge of the functional layer 126 after formation (curing) is slightly thicker. Therefore, the second silicon oxide film 302 is made sufficiently thick in consideration of that amount.

  Next, as shown in FIG. 20, the second silicon oxide film 302 is patterned by photolithography to form a lower partition wall 304 surrounding the pixel electrode 108.

  Next, as shown in FIG. 21, a polyimide film 110 as an organic material layer is formed on the entire surface of the substrate.

  Here, the film thickness of the polyimide film 110 is preferably formed to be smaller than the film thickness of the second silicon oxide film. The purpose of forming the polyimide film 110 is to make the surface of the partition upper part 306, which will be described later, lyophobic and prevent the dropped liquid material from flowing out onto the adjacent pixels, because the height is not so necessary. It is. In addition, increasing the film thickness of the polyimide film 110 more than necessary can increase the level difference on the substrate surface due to the partition walls and reduce the contact of the cathode layer 128 described later.

  Next, as shown in FIG. 22, the polyimide film 110 is patterned by photolithography to form a partition upper portion 306 surrounding the pixel electrode 108. The partition wall lower portion 304 and the partition wall upper portion 306 form a partition wall (hereinafter referred to as a two-layer partition wall) 30 composed of two layers surrounding the pixel electrode 108.

  Here, the patterning is performed so that the width of the remaining polyimide film 110, that is, the upper part 306 of the partition is slightly narrower than the width of the second silicon oxide film 302 after the patterning, that is, the lower part 304 of the partition. . This is because the polyimide film 110 is not left on the side surface of the partition wall lower portion 304 obtained by patterning the second silicon oxide film 302 in consideration of misalignment in photolithography.

Next, as shown in FIGS. 23 and 24, a plasma treatment with oxygen plasma B and a plasma treatment with CF ₄ plasma A are continuously performed on the entire surface of the substrate. Oxygen plasma B removes organic residues on the surface of the pixel electrode 108 and the lower part of the partition wall 304, that is, the portion formed by the second silicon oxide film 302. Then, the upper surface of the partition wall 306, that is, the surface of the portion formed of the polyimide film 110 becomes liquid repellent by the CF ₄ plasma A. The plasma treatment using CF ₄ may use another gas containing fluorine atoms, such as SF ₆ or CHF ₃ .

  Next, as shown in FIG. 25, the material constituting the hole injection layer is dissolved or dispersed in a solvent from the nozzle 120 of the ink jet device on the pixel electrode 108 surrounded by the two-layer partition wall 30. The liquid material C is dropped. Since the surface of the partition upper portion 306 has liquid repellency, the outflow of the liquid material C onto the adjacent pixel electrode can be avoided.

  Next, as shown in FIG. 26, the solvent is removed by a drying / curing process to form the hole injection layer 122.

  Next, as shown in FIG. 27, the material constituting the organic EL layer is dissolved or dispersed in a solvent from the nozzle 120 of the ink jet device on the hole injection layer 122 formed on the pixel electrode 108. Liquid material D is dropped. As described above, since the hole injection layer 122 is formed on the pixel electrode 108, the recess formed by the two-layer partition wall 30 is shallow. Therefore, the liquid material D immediately after dropping is in contact with not only the partition wall lower part 304 but also the partition wall upper part 306.

  Next, as shown in FIG. 28, the light-emitting layer 124 is formed by removing the solvent by a drying / curing process. As described above, since the thickness of the second silicon oxide film 302 that is patterned to become the partition lower portion 304 is sufficiently thick, the light emitting layer 124 obtained by removing the solvent does not contact the partition upper portion 306. .

  Finally, as shown in FIG. 29, as in the first embodiment, a cathode layer 128 is formed on the entire surface of the substrate by a well-known technique, and then an organic EL device is completed through some well-known steps.

  In this embodiment, the liquid material immediately after dropping is in contact with the liquid-repellent partition upper part 306, but after the time when the solvent is abundant immediately after dropping, the surface of the liquid material is dried and cured. It leaves | separates from the liquid-repellent partition upper part 306. FIG. Thereafter, drying and curing proceed in a state where the liquid material is not in contact with the portion of the liquid repellent surface, and the formed functional layer is formed on the side surface of the partition wall lower portion 304 and the pixel electrode 108 whose surface is lyophilic. Will only touch.

  As described above, in the process of forming the functional layer, if the liquid material containing the material constituting the organic EL layer is in contact with the partition wall of the liquid repellent surface, the influence extends to the center of the pixel electrode and is dried / cured. The film thickness of the later functional layer varies, and the cross section has a wavy shape. Further, in the periphery of the pixel electrode, the liquid material is dried and hardened while being repelled by the partition wall on the liquid repellent surface, so that the liquid material becomes extremely thin and may cause a short circuit between the electrodes.

  However, since the two-layer partition wall 30 can maintain the liquid repellency of the upper surface (partition wall upper portion 306) and the side surface (partition wall lower portion 304) can be made lyophilic, it is possible to suppress variations in film thickness. Furthermore, since the drying / curing process is performed in a state where the liquid material is attracted to the lyophilic partition wall lower portion 304, the peripheral portion of the formed functional layer tends to be slightly thick and the other portions tend to be flat. become. Therefore, even when the liquid material is dropped by the inkjet method and the functional layer 126 is obtained by drying / curing by the implementation of the present embodiment, color unevenness due to variations in current density in the functional layer 126, particularly in the light emitting layer 124, It is possible to obtain an organic EL device in which unevenness in luminance and a decrease in lifetime are suppressed, and further, there is no short circuit between electrodes in the periphery of the pixel electrode 108.

(Fourth embodiment)
30 to 37 show a fourth embodiment of a method for manufacturing an organic EL device according to the present invention. Hereinafter, a method for manufacturing an organic EL device according to the fourth embodiment will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the component which is common in FIGS. 6-14 and FIGS. 19-29.

  First, as shown in FIG. 30, a TFT 104 as a switching element including a gate electrode 103 is formed on a substrate 102, and a silicon oxide film 105 as an interlayer insulating film is formed on the upper surface (over the entire surface of the substrate). Then, a contact hole 106 is formed at a predetermined position on the TFT 104, and a pixel electrode 108 that is electrically connected to the TFT 104 through the contact hole 106 is formed. The pixel electrode 108 uses ITO because it needs transparency and conductivity.

  Next, as shown in FIG. 31, a second silicon oxide film 302 is formed on the entire surface of the substrate 102. Similarly to the third embodiment, the functional layer 126 (see FIG. 36) formed on the pixel electrode 108 in a subsequent process is formed to be slightly thicker.

  Further, as shown in FIG. 32, a polyimide film 110 as an organic material layer is formed on the entire surface of the substrate on which the second silicon oxide film 302 is formed. Here, the film thickness of the polyimide film 110 is made thinner than that of the second silicon oxide film 302 as in the third embodiment.

Then, as shown in FIG. 33, plasma treatment with CF ₄ plasma A is performed to make the surface of the polyimide film 110 liquid-repellent by injecting fluorine atoms.

  Next, as shown in FIG. 34, the second silicon oxide film 302 and the polyimide film 110 are collectively patterned by photolithography to form the two-layer partition walls 30 having different materials between the partition upper part 306 and the partition lower part 304. The pixel electrode 108 is formed so as to surround it. Unlike the third embodiment, since there is no need to consider misalignment between the partition upper portion 306 and the partition lower portion 304, the width of the two-layer partition 30 is to prevent the dropped liquid material C from flowing out (to adjacent pixels). If this is possible, it will be sufficient.

  Next, as shown in FIG. 35, plasma treatment with oxygen plasma B is performed on the entire surface of the substrate 102. During patterning of the polyimide film 110, organic residues remaining on the substrate 102, particularly on the pixel electrode 108, are removed by oxidation, and the surface of the pixel electrode 108 and the surface of the silicon oxide film below the two-layer partition wall 30 are removed. Is made more lyophilic.

  Thereafter, the functional layer 126 including the hole injection layer 122 and the light emitting layer 124 is formed through the same steps as in FIGS. 25 to 28 of the third embodiment (see FIG. 36). The liquid material immediately after dropping can also contact the upper partition wall 306, but the light emitting layer 124 obtained by removing the solvent is not in contact with the upper partition wall 306 as in the third embodiment. .

  Finally, as shown in FIG. 37, as in the first embodiment, a cathode layer 128 is formed on the entire surface of the substrate 102 by a well-known technique, and thereafter, an organic EL device is completed through some well-known steps. .

  Similar to the third embodiment, the dried and cured functional layer 126 is in contact only with the partition wall lower part 304 and the pixel electrode 108 whose surface is liquid repellent. For this reason, it is possible to obtain an organic EL device in which color unevenness, brightness unevenness, and lifetime reduction are suppressed, and further, there is no short-circuit between electrodes in the peripheral portion. Further, unlike the third embodiment, the photolithography for forming the two-layer partition wall 30 is only required once, and as described above, the width of the two-layer partition wall 30 is also the minimum necessary to prevent the liquid material from flowing out. Therefore, the light emitting area in the substrate area can be improved. The plasma conditions are not particularly limited as long as the upper partition 306 is liquid repellent and the surfaces of the lower partition 304 and the pixel electrode 108 are lyophilic, as in the third embodiment. It is the same.

(Fifth embodiment)
38 to 48 show a fifth embodiment of a method for manufacturing an organic EL device according to the present invention. The process is similar to that of the fourth embodiment except that the thickness of the second silicon oxide film 302 is very thick. Hereinafter, a method for manufacturing an organic EL device according to the fifth embodiment will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the component which is common in FIGS. 6-14 and FIGS. 19-29.

  First, as shown in FIG. 38, a TFT 104 as a switching element including a gate electrode 103 is formed on a substrate 102, and a silicon oxide film 105 as an interlayer insulating film is formed on the upper surface (over the entire surface of the substrate). Then, a contact hole 106 is formed at a predetermined position on the TFT 104, and a pixel electrode 108 that is electrically connected to the TFT 104 through the contact hole 106 is formed. Since the pixel electrode 108 needs transparency and conductivity, ITO is used.

  Next, as shown in FIG. 39, a second silicon oxide film 302 as an inorganic material layer is formed on the entire surface of the substrate 102. At this time, a hole injection layer 122 formed on the pixel electrode 108, which will be described later (see FIG. 45), is used as a bottom, and a recess having a partition wall lower part 304 obtained by patterning the second silicon oxide film 302 as a side part. The second silicon oxide film 302 is sufficiently thick so that it does not overflow even when a predetermined amount of a liquid material D containing a material constituting the organic EL layer is dropped, as will be described later (see FIG. 46). That is, in the third and fourth embodiments, the second layer is formed so as to be thicker than the cured film thickness of the functional layer formed on the pixel electrode 108 in the subsequent process (the solvent is removed by drying). Although the silicon oxide film 302 is formed, in this embodiment, the thickness of the liquid material immediately after dropping is also set so as not to exceed the second silicon oxide film 302.

  Next, as shown in FIG. 40, a polyimide film 110 as an organic material layer is formed on the entire surface of the substrate 102 on which the second silicon oxide film 302 is formed. In this embodiment, the polyimide film 110 is formed only as thin as possible because the purpose of forming the polyimide film 110 is only to make the upper surface of the partition wall liquid-repellent. This is because a step on the substrate surface after the functional layer 126 described later is formed, and the cathode layer 128 is easily formed.

Next, as shown in FIG. 41, plasma treatment with CF ₄ plasma A is performed to make the surface of the polyimide film 110 liquid-repellent by injecting fluorine atoms.

  Next, as shown in FIG. 42, the second silicon oxide film 302 and the polyimide film 110 are collectively patterned by photolithography to surround the pixel electrode 108, and the two layers are made of different materials in the upper layer and the lower layer. A partition wall 30 is formed. A portion obtained by patterning the second silicon oxide film 302 becomes a partition lower portion 304, and a portion obtained by patterning the polyimide film 110 becomes a partition upper portion 306.

  Next, as shown in FIG. 43, plasma treatment with oxygen plasma B is performed on the entire surface of the substrate. Organic residues are removed by an oxidizing action, and the surface of the pixel electrode 108 and the silicon oxide film surface of the partition wall lower part 304 are made more lyophilic.

  Next, as shown in FIG. 44, a liquid material C obtained by dissolving or dispersing a material constituting the hole injection layer from the nozzle 120 of the inkjet device in a solvent is dropped onto the pixel electrode 108. A portion obtained by patterning the second silicon oxide film 302 has a sufficiently high partition wall lower portion 304, so that the liquid material C immediately after dropping contacts only the partition wall lower portion 304 and does not contact the partition wall upper portion 306. .

  Next, as shown in FIG. 45, the solvent of the liquid material C is removed by a drying / curing process to form the hole injection layer 122.

  Next, as shown in FIG. 46, a liquid material D obtained by dissolving or dispersing the material constituting the organic EL layer from the nozzle 120 of the inkjet device in a solvent is dropped. As described above, since the hole injection layer 122 is formed on the pixel electrode 108, the depression formed by the two-layer partition wall 30 is shallow. However, since the height of the partition wall lower part 304 is sufficiently high, the liquid material D immediately after dripping also contacts only the partition wall lower part 304 and does not contact the partition wall upper part 306.

  Next, as shown in FIG. 47, the solvent of the liquid material D is removed by a drying / curing process to form the light emitting layer 124. A functional layer 126 is formed by the hole injection layer 122 and the light emitting layer 124.

  Finally, as shown in FIG. 48, as in the first embodiment, the cathode layer 128 is formed on the entire surface of the substrate by a well-known technique, and then the organic EL device is completed through some well-known steps.

  Unlike the third and fourth embodiments, not only the functional layer after drying / curing, but also the liquid material immediately after dropping, because the surface of the partition wall does not contact the liquid-repellent part, the liquid material is repelled, Occurrence of variations in film thickness can be further suppressed. Note that the plasma processing conditions and the like are not particularly limited as in the third and fourth embodiments.

Sectional drawing which shows the outline | summary of this invention. Sectional drawing which shows the outline | summary of this invention. Sectional drawing which shows the outline | summary of this invention. Sectional drawing which shows the outline | summary of this invention. Sectional drawing which shows the outline | summary of this invention. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. 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Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 3rd Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 3rd Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 3rd Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 4th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment. Sectional drawing explaining the manufacturing method of the organic electroluminescent apparatus concerning 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Partition, 11 ... Liquid-repellent treated part, 12 ... Partition upper surface, 14 ... Side wall of partition, 20 ... Mask for selective plasma, 22 ... Part not covered with partition mask, 30 ... Two-layer partition, 102 DESCRIPTION OF SYMBOLS ... Substrate, 103 ... Gate electrode, 104 ... TFT, 105 ... Silicon oxide film as interlayer insulating film, 106 ... Contact hole, 108 ... Pixel electrode, 110 ... Photosensitive polyimide film, 111 ... Upper surface portion of polyimide film, 120 ... nozzles of the ink jet device, 122 ... hole injection layer, 124 ... light-emitting layer, 126 ... functional layer, 128 ... cathode layer, 302 ... second silicon oxide film, 304 ... partition wall bottom, 306 ... partition wall upper, a ... CF ₄ Plasma, B ... oxygen plasma, C ... liquid material obtained by dissolving or dispersing a material constituting the hole injection layer in a solvent, D ... a material constituting the organic EL layer as a solvent Liquid material obtained by dissolving or dispersing.

Claims (14)

Forming a pixel electrode on the substrate;
Forming a partition wall in which at least a part of the surface has liquid repellency and the other part of the surface has lyophilicity so as to surround the pixel electrode;
Forming a functional layer including at least a light emitting layer by dropping and drying a liquid material on the pixel electrode; and
Forming a cathode layer on the substrate on which the functional layer is formed;
The manufacturing method of the organic electroluminescent apparatus characterized by the above-mentioned.   2. The organic EL device according to claim 1, wherein the step of forming the partition includes a step of forming an organic material layer on the entire surface of the substrate and patterning the organic material layer. Production method.   The step of forming the partition includes a step of performing plasma treatment under a condition such that liquid repellency becomes higher on the surface of the organic material layer before patterning the organic material layer. The manufacturing method of the organic EL device according to claim 2, wherein   In the step of forming the partition wall, after the organic material layer is patterned to form the partition wall, at least a part of the upper surface of the partition wall is subjected to plasma treatment under conditions that make liquid repellency higher. The method of manufacturing an organic EL device according to claim 2, further comprising:   5. The method of manufacturing an organic EL device according to claim 1, further comprising a step of performing oxygen plasma treatment on the substrate after forming the partition and before forming the functional layer. . Forming a pixel electrode on the substrate;
Forming a partition made of a plurality of layers including at least a top layer made of an organic material and a bottom layer made of an inorganic material around the pixel electrode;
Applying a treatment such that part or the whole of the surface of the organic material layer becomes liquid repellent;
Forming a functional layer including at least a light emitting layer by dropping and drying a liquid material on the pixel electrode; and
Forming a cathode layer on the substrate on which the functional layer is formed;
Including
A method of manufacturing an organic EL device, wherein the inorganic material layer is formed thicker than the functional layer.   The method of manufacturing an organic EL device according to claim 6, wherein the inorganic material layer is formed thicker than a liquid surface height of the liquid material immediately after dropping.   8. The method of manufacturing an organic EL device according to claim 6, wherein the inorganic material layer is formed thicker than the organic material layer.   9. The method of manufacturing an organic EL device according to claim 6, further comprising a step of forming the partition walls by patterning the plurality of layers at once.   9. The partition wall comprising the plurality of layers is formed by patterning at least one layer before forming a layer above the partition wall, according to any one of claims 6 to 8. Manufacturing method of organic EL device.   11. The method of manufacturing an organic EL device according to claim 6, further comprising a step of performing oxygen plasma treatment on the entire surface of the substrate after forming the partition and before forming the functional layer. Method. A pixel electrode disposed on the substrate;
A partition wall surrounding the pixel electrode;
A functional layer including at least a light emitting layer;
A counter electrode facing the pixel electrode through the functional layer;
An organic EL device having
An organic EL device, wherein at least a part of a surface of the partition wall has liquid repellency, and at least a part of the surface of the partition wall in contact with the functional layer has a lyophilic property.   The organic EL device according to claim 12, wherein the partition wall is formed of a plurality of layers including at least an uppermost layer and a lowermost layer. A pixel electrode disposed on the substrate;
A partition wall surrounding the pixel electrode;
A functional layer including at least a light emitting layer;
A counter electrode facing the pixel electrode through the functional layer;
An organic EL device having
The surface of the uppermost layer has liquid repellency, the surface of the lowermost layer has lyophilicity, and the film thickness of the lowermost layer is larger than the film thickness of the functional layer. .

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