JP2006000772A - Thin film forming method, method for manufacturing organic el device and liquid droplet discharging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film forming method at the coating step of which uneven drying can be decreased easily and to provide a method for manufacturing an organic EL device and a liquid droplet discharging apparatus. <P>SOLUTION: This thin film forming method for forming a thin film on a substrate in the area to be coated by an ink-jet method comprises the coating step of applying a liquid material, which is prepared by dissolving or dispersing a thin film forming material in a solvent or a dispersion medium, to the area to be coated by the ink-jet method in a high-pressure atmosphere, for example, in the atmosphere of the pressure equal to or higher than the vapor pressure of the solvent or the dispersion medium. As a result, uneven drying can be decreased easily at the coating step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thin film formation method and a droplet discharge device, and more particularly to a thin film formation method and a droplet discharge device for forming a thin film on a coating region of a substrate by an inkjet method.

  For the formation of a thin film, for example, a spin coating method which is one of thin film coating methods is generally used. This spin coating method is a method of forming a thin film by forming a thin film by rotating a substrate and applying the whole surface of the substrate by centrifugal force after the liquid material is dropped on the substrate. The film thickness is controlled by viscosity or the like.

  However, in the spin coating method, since most of the supplied liquid material is scattered, there is a problem that it is necessary to supply a large amount of liquid material, and there is a lot of waste, resulting in an increase in production cost. Further, since the substrate is rotated, the liquid material flows from the inner side to the outer side due to the centrifugal force, and the film thickness of the outer peripheral region tends to be thicker than that of the inner side.

  Against this background, recently, a droplet discharge method such as an ink jet method has been proposed, and a droplet discharge device has been proposed as a device for carrying out this coating method. This droplet discharge device is preferably used mainly for forming a thin film because a predetermined amount of liquid material can be disposed at a desired position. For example, it is used to produce a light emitting layer and a hole injection / transport layer in an organic EL device.

  Patent Document 1 is known as a method for producing a hole injection / transport layer and a light emitting layer of an organic EL device with a droplet discharge device. In this document, a partition wall (bank) is formed on a substrate in advance, and a liquid material is discharged onto a region defined by the partition wall, that is, a coating region (pixel region), and then dried, whereby holes are formed. A thin film to be an injection / transport layer and a light emitting layer is formed.

Japanese Patent No. 3328297

  However, in the method described above, unevenness of drying of the liquid material applied in the plane of the substrate occurs, so that a flat and uniform thin film may not be formed. This phenomenon will be described with reference to FIG. As shown in FIG. 10, first, a liquid material 510 in which a thin film forming material is dissolved in a low boiling point solvent is applied to a coating region 503 defined by a bank 502 on a substrate 501 with a droplet discharge head under normal pressure conditions. Apply in the order of the arrows. In this case, the drying time differs between the area where the droplets are applied first and the area where the droplets are applied last, and the drying state varies depending on the order in which the liquid is applied. The liquid material applied to the first side is naturally dried, and the liquid material 503 is attracted or repelled to the bank 502, and the film profile becomes a concave shape or a convex shape. As described above, there is a problem in that drying unevenness (profile unevenness) occurs in the pixels in the surface due to the lime lag until the drying process is started. In the substrate 501, the dry state may be different depending on the atmosphere (vapor) of the liquid material 503 between the central portion and the outer peripheral portion. That is, natural drying is more likely to proceed in the outer peripheral portion than in the central portion.

  In this case, in order to eliminate drying unevenness (profile unevenness) due to the time lag of the coating time, a high boiling point solvent is used as a liquid to prevent drying during the coating process, and in-plane by drying under reduced pressure in the drying process. It is conceivable to quickly dry the two at the same time. However, in order to quickly dry the high boiling point solvent, it is necessary to realize an atmosphere with a high degree of vacuum. In addition, since the film profile is affected by the arrival speed of the vacuum, the apparatus used in the drying process is required to have high capability.

  The present invention has been made in view of the above problems, and provides a thin film forming method, an organic EL device manufacturing method, and a droplet discharge device capable of reducing drying unevenness by a simple method in a coating process. For the purpose.

  In order to solve the above-described problems and achieve the object, the present invention provides a liquid film in which a thin film forming material is dissolved or dispersed in a solvent or a dispersion medium in a thin film forming method in which a thin film is formed on an application region of a substrate by an inkjet method. The body is applied to the application region in a high-pressure atmosphere by an inkjet method.

  As a result, by setting the atmosphere during the coating process to a high pressure, drying during the coating process can be prevented, and uneven drying within the surface can be eliminated. As a result, it is possible to provide a thin film forming method that can reduce drying unevenness by a simple method in the coating process.

  In other words, even when a low-boiling solvent is used, since the coating is performed in a high-pressure atmosphere, drying during the coating process can be prevented and in-plane drying unevenness can be prevented. For this reason, when a low boiling point solvent is used, sufficient drying proceeds even in a low vacuum in the drying process, and a flat film profile can be formed. As a result, in the drying process, the ability required of the vacuum pump, such as the degree of vacuum and the speed to reach the vacuum, can be reduced.

  In addition, low-boiling solvents often have low viscosity, but even when low-viscosity solvents are used, drying of the nozzle surface of the head can be suppressed under a high-pressure atmosphere, and intermittent printability can be improved. Is possible. As a result, by using the thin film forming method of the present invention, a low boiling point / low viscosity solvent can be used, and the degree of freedom of usable ink is improved.

  According to a preferred aspect of the present invention, it is desirable that the high-pressure atmosphere is an atmosphere having a vapor pressure higher than that of the solvent or dispersion medium. Thereby, evaporation of the solvent or the dispersion medium during the coating process can be completely suppressed.

  According to a preferred aspect of the present invention, the solvent or dispersion medium is preferably a low boiling point solvent or dispersion medium. As a result, even when a low-boiling solvent or dispersion medium is used, drying unevenness can be reduced by a simple method in the coating step.

  Moreover, according to a preferable aspect of the present invention, it is desirable that the application region is subjected to a lyophilic treatment. Thereby, the liquid material can be easily applied to the application region, and the liquid material can be uniformly applied to the application region.

  Moreover, according to a preferable aspect of the present invention, it is desirable that the application area is an area defined by a partition wall. As a result, the presence of the partition enables a relatively large amount of liquid material to be applied to the application region. Therefore, a relatively thick film can be formed by one discharge without repeating the application of the liquid material. It becomes possible.

  According to a preferred aspect of the present invention, the thin film is preferably a light emitting layer or a hole / injection transport layer of an organic EL device. Moreover, the manufacturing method of the organic EL device of the present invention includes a thin film forming step of forming the thin film by the thin film forming method of the present invention. Thereby, the light emitting layer or the hole / injection transport layer of the organic EL device can be made flat, and high-quality display characteristics can be obtained.

  According to a preferred aspect of the present invention, the thin film is preferably a color filter. Thereby, the light emitting layer or the hole / injection transport layer of the organic EL device can be made flat, and high-quality display characteristics can be obtained.

  In order to solve the above-described problems and achieve the object, the present invention provides a liquid discharge device in which a thin film forming material is dissolved or dispersed in a coating region of a substrate in a liquid droplet discharge device that discharges a liquid material from a liquid droplet discharge head. A body is applied to the application region under a high-pressure atmosphere by the droplet discharge head.

  As a result, by setting the atmosphere during the coating process to a high pressure, drying during the coating process can be prevented, and uneven drying within the surface can be eliminated. As a result, it is possible to provide a droplet discharge device that can reduce drying unevenness by a simple method in the coating process.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. In the following embodiments, an organic EL device will be described as an example, but the present invention is not limited to this.

[Droplet discharge device]
(Overall configuration of droplet discharge device)
FIG. 1 is a schematic perspective view showing the overall configuration of a droplet discharge apparatus according to an embodiment of the present invention. As shown in FIG. 1, the droplet discharge apparatus according to the present embodiment includes, for example, a droplet discharge unit 13 having one or a plurality of droplet discharge heads 32 that discharge a liquid material 11 onto the surface of a substrate 10, and a liquid The moving device 14 includes a moving unit 14 that relatively moves the positions of the carriage 12 that supports the droplet discharge head 32 and the substrate 10, and a control unit 15 that controls the droplet discharging unit 13 and the moving unit 14. .

  The moving means 14 supports the droplet discharge head 32 downward on the substrate 10 placed on the substrate stage 16 and is movable in the X-axis direction by the movable stage 18. 17 and a stage driving unit 19 that moves the substrate in the Y-axis direction together with the substrate stage 16 with respect to the upper droplet discharge head group 32.

  The head support portion 17 is centered on a mechanism such as a linear motor that can move and position the droplet discharge head 32 with respect to the substrate 10 at an arbitrary moving speed in the vertical axis direction (Z axis) and the vertical axis. A mechanism such as a stepping motor that can be set at an arbitrary angle with respect to the lower substrate 10 by rotating the droplet discharge head group.

  The stage driving unit 19 rotates the substrate stage 16 around the vertical axis to discharge the substrate stage 16 and the θ-axis stage 20 that can be set at an arbitrary angle with respect to the upper droplet discharge head group 32. And a stage 21 that moves and positions the head group 32 in the horizontal direction (Y direction). The θ-axis stage 20 is composed of a stepping motor or the like, and the stage 21 is composed of a linear motor or the like.

  The discharge means 13 includes a droplet discharge head 32 and a tank 23 connected to the droplet discharge head 32 via a tube 22. The tank 23 stores the liquid material 11 and supplies the liquid material 11 to the droplet discharge head 32 via the tube 22. The liquid 11 is obtained by dissolving or dispersing a thin film forming material with a solvent or a dispersion medium. With such a configuration, the droplet discharge means 13 discharges the liquid 11 stored in the tank 23 from the droplet discharge head 32 and applies it onto the substrate 10. The droplet discharge head 32 compresses a liquid chamber by, for example, a piezoelectric element, and discharges droplets (liquid material) with the pressure, and has a plurality of nozzles (nozzle holes) arranged in one or a plurality of rows. is doing.

(head)
FIG. 2 is an exploded perspective view of the droplet discharge head 32, and FIG. 3 is a cross-sectional view of the droplet discharge head 32. As shown in FIGS. 2 and 3, the droplet discharge head 32 includes, for example, a stainless steel nozzle plate 41 and a vibration plate 42, and both are joined via a partition member (reservoir plate) 43. A plurality of spaces 44 and a liquid reservoir 45 are formed between the nozzle plate 43 and the vibration plate 42 by a partition member. Each space 44 and the inside of the liquid reservoir 45 are filled with the liquid material 11 (not shown), and each space 44 and the liquid reservoir 45 communicate with each other via a supply port 46. The nozzle plate 41 is formed with minute hole nozzles 47 for ejecting the liquid material 11 from the spaces 44. On the other hand, a hole 47 a for supplying the liquid 11 to the liquid reservoir 45 is formed in the vibration plate 42.

  A piezoelectric element (piezo element) 48 is joined to the surface of the diaphragm 42 opposite to the surface facing the space, as shown in FIGS. The piezoelectric element 48 is positioned between a pair of electrodes 49 and 49 as shown in FIG. 3, and bends so that when energized, it protrudes outward. The diaphragm 42 to which the piezoelectric element 48 is bonded in such a configuration is integrally bent with the piezoelectric element 48 and is bent outward at the same time, whereby the internal volume of the space 44 is increased. Is increasing. Accordingly, the liquid material corresponding to the increased volume in the space 44 flows from the liquid reservoir 45 through the supply port 46. Further, when energization to the piezoelectric element 48 is released from such a state, both the piezoelectric element 48 and the diaphragm 43 return to their original shapes. Therefore, since the space 44 also returns to its original volume, the pressure of the liquid material 11 inside the space rises, and spray droplets of the liquid material 11 are ejected from the nozzle 47 toward the substrate 10.

  As a method of the droplet discharge head 32, a method other than the piezo jet type using the piezoelectric element as described above may be used, and vibration is applied or pressure is applied to the tank by an ultrasonic motor, a linear motor, or the like. By applying the liquid crystal, the liquid material 11 may be emitted from the minute hole.

  The control means 15 in FIG. 1 is constituted by a CPU such as a microprocessor for controlling the entire apparatus, a computer having various signal input / output functions, and the like, as shown in FIG. By being electrically connected to the discharge means 13 and the movement means 14, respectively, at least one of the discharge operation by the droplet discharge means 13 and the movement operation by the movement means 14 is controlled in this embodiment. ing. With such a configuration, the discharge condition of the liquid discharge liquid is adjusted, and the coating amount of the thin film to be formed is controlled.

  That is, the control means 15 has a control function for adjusting the discharge interval of the liquid discharge liquid with respect to the substrate, a control function for adjusting the discharge amount of the liquid material 11 per dot, It has a control function for adjusting the angle (θ) between the arrangement direction and the movement direction by the movement mechanism, and a control function for setting discharge conditions in each area by dividing the substrate into a plurality of areas.

  Further, the control means 15 is a control mechanism for adjusting the discharge interval, and a control function for adjusting the discharge interval by adjusting the relative movement speed between the substrate 100 and the droplet discharge head 12, and the discharge in the moving means. A control function for adjusting the discharge interval by adjusting the time interval, and a control function for adjusting the discharge interval by arbitrarily setting nozzles that simultaneously discharge the liquid material among the plurality of nozzles. Instead of the above configuration, the droplet discharge head 12 may have means for moving in the X axis and Y axis, and the stage 16, 20 or 21 has means for moving in the X axis, Y axis, and Z axis. It may be allowed.

(Droplet discharge device application method)
The droplet discharge device 1 of this embodiment is disposed in a high-pressure chamber (not shown), and the liquid material 11 is applied in a high-pressure atmosphere. Here, the high-pressure atmosphere is desirably set to be equal to or higher than the vapor pressure of the solvent or dispersion medium of the liquid 11 in order to prevent drying unevenness of the liquid 11. For example, when xylene, mesitylene, isopropylbenzene, ethylbenzene, diethylbenzene, todecylbenzene, and triethylbenzene are used as the solvent or dispersion medium of the liquid 11, the vapor pressure of xylene is 870 Pa, the vapor pressure of mesitylene is 200 Pa (20 ° C. ), Isopropylbenzene vapor pressure 430 Pa (20 ° C.), ethylbenzene vapor pressure 0.9 kPa (20 ° C.), diethylbenzene vapor pressure 0.13 kPa (20 ° C.), todecylbenzene vapor pressure <10 kPa (20 ° C.), It is desirable that the vapor pressure of triethylbenzene be higher than 147 Pa (20 ° C.).

  FIG. 4 is an explanatory diagram for explaining an example of a coating method of the droplet discharge device 100. In FIG. 4, the substrate 10 is held on the substrate stage 16. In the substrate 10, coating areas 52 partitioned by banks 51 are formed in a matrix. The application region 52 is a region where pixels and the like are formed. The planar image of the application region 52 has a substantially rectangular shape determined by the long side and the short side. The substrate stage 16 holds the substrate 10 so that the long side direction of the coating region 52 of the substrate 10 is parallel to the X axis direction and the short side direction is parallel to the Y axis direction.

  In FIG. 4, first, the position of the carriage 12 is adjusted to the upper left position of the substrate 10 on the substrate stage 16. While moving the carriage 12 relative to the substrate stage 16 in the Y-axis direction, droplets of the liquid 11 are ejected onto the application region 52 of the substrate 10 in a high-pressure atmosphere by the droplet ejection head 32 along the Y-axis direction. .

  Next, the carriage 12 is moved in the X-axis direction by the drawing width (effective scanning width). Thereafter, while moving the carriage 12 relative to the substrate stage 16 in the Y-axis direction, the droplets of the liquid 11 are applied to the application region 52 of the substrate 10 in the high-pressure atmosphere by the droplet discharge head 32 along the Y-axis direction. Is discharged. A similar operation is performed until the entire coated surface of the substrate 10 is completed.

  As described above, in this embodiment, the liquid material 11 in which the thin film forming material is dissolved or dispersed in a solvent or a dispersion medium is applied to the application region of the substrate under a high-pressure atmosphere by the inkjet method. By making the atmosphere of this high pressure, drying during the coating process can be prevented and in-plane drying unevenness can be eliminated.

  In other words, even when a low-boiling solvent is used, since the coating is performed in a high-pressure atmosphere, drying during the coating process can be prevented, and in-plane drying unevenness can be prevented. For this reason, when a low boiling point solvent is used, sufficient drying proceeds even in a low vacuum in the drying process, and a flat film profile can be formed. As a result, in the drying process, the ability required of the vacuum pump, such as the degree of vacuum and the speed to reach the vacuum, can be reduced.

  In addition, low-boiling solvents often have low viscosity, but even when low-viscosity solvents are used, drying of the nozzle surface of the droplet discharge head can be suppressed under a high-pressure atmosphere, and intermittent printability can be achieved. It becomes possible to improve. Thus, when the coating method of the present invention is used, a low boiling point / low viscosity solvent can be used, and the degree of freedom of usable ink is improved.

[Manufacturing process of organic EL device]
Next, a method for manufacturing an organic EL device using the thin film forming method of this embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing the manufacturing process of the organic EL device, and FIG. 6 is a manufacturing process diagram of the organic EL device. As shown in FIG. 5, the manufacturing process of the organic EL device of this example includes (1) a partition formation process (S101), (2) a plasma treatment process (S102), and (3) a hole injection / transport layer. Forming step (S103), (4) surface modification step (S104), (5) light emitting layer forming step (S105), (6) cathode forming step (S106), and (7) sealing step (S107). ).

(1) Partition Generation Step As shown in FIG. 6A, in the partition formation step, a transparent electrode 101 made of ITO or the like formed on a substrate 100 on which a TFT or the like (not shown) is provided in advance as necessary. On top of this, an inorganic bank layer 102a and an organic bank layer 102b are sequentially stacked to form a bank layer (partition wall) 102 that separates the pixel regions.

  The inorganic bank layer 102a is formed by forming an inorganic film such as silicon oxide, titanium oxide, or silicon nitride on the entire surface of the substrate 100 and the transparent electrode 101 by, for example, a CVD method, a sputtering method, a vapor deposition method, and then etching the inorganic film. Then, patterning is performed to form an opening 103a in the pixel region on the transparent electrode 101. However, at this time, the inorganic bank layer 102a is left up to the peripheral edge of the transparent electrode 101. Further, the film thickness of the inorganic bank layer 102a is preferably in the range of 50 to 200 nm, particularly 150 nm.

  Next, the organic bank layer 102b is formed on the entire surface of the substrate 100, the transparent electrode 101, and the inorganic bank layer 102a. The organic bank layer 102b is formed by applying an organic resin such as an acrylic resin or a polyimide resin dissolved in a solvent by spin coating, dip coating, or the like. Then, the organic bank layer 102b is etched by a photolithography technique or the like to provide the opening 103b. The opening 103b of the organic bank layer 102b is preferably formed slightly wider than the opening 103a of the inorganic bank layer 102a, as shown in FIG. Thereby, an opening 103 penetrating the inorganic bank layer 102a and the organic bank layer 102b is formed on the transparent electrode 101. The planar shape of the opening 103 may be any of a circle, an ellipse, a square, and a stripe. However, since the ink composition has a surface tension, in the case of a square or the like, the corner is rounded. Is preferred.

(2) Plasma treatment step Next, in the plasma treatment step, a region showing ink affinity and a region showing ink repellency are formed on the surface of the bank portion 102. This plasma treatment process is roughly divided into a preliminary heating process, an ink repellent process for making the entire surface ink-philic, an ink repellent process for making the organic bank layer 102b ink repellent, and a cooling process.

In the ink-philic process, plasma treatment (O ₂ plasma treatment) using oxygen as a reactive gas is performed in an air atmosphere. Specifically, the substrate 100 including the bank unit 102 is placed on a sample stage with a built-in heater, and is irradiated with oxygen in a plasma state. By this O ₂ plasma treatment, hydroxyl groups or oxygen atoms are introduced into the exposed surfaces of the transparent electrode 101 and the inorganic bank layer 102a and the entire surface of the organic bank layer 102b, thereby imparting ink affinity.

Next, in the ink repellent process, plasma treatment (CF ₄ plasma treatment) using tetrafluoromethane (carbon tetrafluoride) as a reactive gas is performed in an air atmosphere. Specifically, the substrate 100 including the bank unit 12 is placed on a sample stage with a built-in heater, and is irradiated with plasma tetrafluoromethane (carbon tetrafluoride). The processing gas is not limited to tetrafluoromethane (carbon tetrafluoride), and other fluorocarbon gases can be used. By the CF ₄ plasma treatment, fluorine groups are introduced into the organic bank layer to which ink-philicity has been imparted in the previous step, and ink repellency is imparted. Organic substances such as acrylic resin and polyimide resin constituting the organic bank layer 102b can be easily made ink-repellent by irradiating plasma fluorocarbon with hydroxyl groups or oxygen atoms replaced with fluorine groups or fluorocarbon groups. It is. On the other hand, the exposed surfaces of the transparent electrode 101 and the inorganic bank layer 102a are also somewhat affected by the CF ₄ plasma treatment, but do not affect the affinity.

In the above plasma treatment process, the organic bank layer 102b and the inorganic bank layer 102a of different materials are sequentially subjected to O ₂ plasma treatment and CF ₄ plasma treatment, whereby the bank portion 102 has an ink-philic region and a repellent property. An ink-based region can be easily provided.

(3) Hole Injection / Transport Layer Formation Step In the hole injection / transport layer formation step, the droplet discharge device 1 is placed in a high-pressure chamber (not shown) and a hole injection / transport layer material (thin film) is formed in a high-pressure atmosphere. After the liquid material 105a containing the forming material) is discharged to the opening 103 on the transparent electrode 101, the hole injection / transport layer 106 is formed by performing a drying process and a heat treatment with a drying apparatus. Here, it is desirable that the high-pressure atmosphere be equal to or higher than the vapor pressure of the solvent or dispersion medium of the liquid 105a in order to prevent drying unevenness of the liquid 105a. In addition, after this hole injection / transport layer formation process, it is preferable to carry out in inert gas atmospheres, such as a nitrogen atmosphere and argon atmosphere without a water | moisture content and oxygen.

  Specifically, as shown in FIG. 6B, the droplet discharge head 32 of the droplet discharge apparatus is filled with the liquid 105a containing the hole injection / transport layer material, and the nozzle of the droplet discharge head 32 is filled. The liquid material 105a in which the liquid amount per droplet is controlled is discharged onto the transparent electrode 101 from the droplet discharge head 32 while the droplet discharge head 32 and the substrate 100 are moved relative to each other with the opening 47 facing the opening 103. To do.

  Here, the discharged liquid 105a is compatible with the exposed surface portions of the ink-philic transparent electrode 101 and the inorganic bank layer 102a, but hardly adheres to the ink-repelled organic bank layer 102b. Even when the liquid is accidentally discharged onto the organic bank layer 102b, the liquid 105a is repelled and rolls onto the exposed surface portions of the transparent electrode 101 and the inorganic bank layer 102a. In addition, since the organic bank layer 102b has a liquid emitting property with respect to the liquid material, it can be prevented from being mixed with the liquid material of the adjacent pixels.

  The liquid 105a used here is a dispersion of 3,4-polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS), that is, polystyrene sulfonic acid (PSS) to polystyrene sulfonic acid (PSS). A dispersion obtained by mixing and further dispersing in water can be used.

  The viscosity of the liquid 105a is preferably about 2 to 20 Ps, and more preferably about 7 to 10 cPs. With this viscosity, the nozzle 47 of the droplet discharge head 32 can be stably discharged without clogging. Further, the liquid material 105a may be printed a plurality of times. In this case, the amount of the liquid 105a at each time may be the same, and the discharge amount may be changed every time. The material of the hole injection / transport layer 106 may be the same for the R, G, and B light emitting layers, or may be changed for each light emitting layer. The discharge amount of the liquid 105a is determined by the size of the opening 103, the thickness of the hole injection / transport layer to be formed, the concentration of the hole injection / transport layer material of the liquid 105a, and the like.

  Thereafter, by performing a drying process in which the liquid component of the liquid material 105a is evaporated and dried by a drying apparatus, a flat hole injection / transport layer 106 is formed on the transparent electrode 101 as shown in FIG. Can be formed. This drying process is performed, for example, in a nitrogen atmosphere at a room temperature and a pressure of about 133.3 Pa (1 Torr). After the drying treatment, it is preferable to remove the polar solvent and water remaining in the hole injection / transport layer 106 by performing a heat treatment in nitrogen, preferably in vacuum, at 200 ° C. for about 10 minutes.

(4) Surface Modification Step Next, a surface modification step is performed prior to the light emitting layer formation step. That is, in the light emitting layer forming step, in order to prevent re-dissolution of the hole injecting / transporting layer 106, a non-soluble material that is insoluble in the hole injecting / transporting layer 106 as a liquid solvent used in forming the light emitting layer. A polar solvent is used. However, since the hole injection / transport layer 106 has low affinity for the nonpolar solvent, the hole injecting / transporting layer 106 containing the nonpolar solvent is ejected onto the hole injecting / transporting layer 106 even if the liquid is discharged. The liquid material is repelled by the injection / transport layer 106 and the hole injection / transport layer 106 and the light-emitting layer cannot be brought into close contact with each other, or the light-emitting layer may not be applied uniformly. Therefore, in order to increase the affinity of the surface of the hole injection / transport layer 106 with respect to the nonpolar solvent, it is preferable to perform a surface modification step before forming the light emitting layer.

(5) Light emitting layer forming step Next, in the light emitting layer forming step, the R light emitting layer 108R, the G light emitting layer 108G, and the B light emitting layer 108B are sequentially formed by an inkjet method. Here, only the method for forming the R light emitting layer will be described, and descriptions of the G light emitting layer and the B light emitting layer will be omitted. In the light emitting layer forming step, the liquid droplet discharge device 1 is placed in a high pressure chamber (not shown), and the liquid 107a containing the R light emitting layer material (thin film forming material) in a high pressure atmosphere is used as the hole injection / transport layer 106. After being discharged onto the top, a drying process and a heat treatment are performed with a drying apparatus to form the R light emitting layer 108R. Here, it is desirable that the high-pressure atmosphere be equal to or higher than the vapor pressure of the solvent or dispersion medium of the liquid 107a in order to prevent drying unevenness of the liquid 105a.

  Specifically, as shown in FIG. 6-4, the droplet discharge head 32 of the droplet discharge apparatus is filled with the liquid material 107a containing the R light emitting layer material, and the nozzle 47 of the droplet discharge head 32 is set to the normal position. While facing the hole injection / transport layer 106 and moving the droplet discharge head 32 and the substrate 100 relative to each other, the droplets are discharged from the discharge nozzle as ink droplets with a controlled amount of liquid, and the liquid material 107a is discharged into holes. It is discharged onto the injection / transport layer 106. In this case, the discharged liquid 107a spreads on the hole injecting / transporting layer 106 and is compatible, but hardly adheres to the ink-repellent treated organic bank layer 102b. Therefore, the liquid 107a does not adhere to the organic bank layer 102b. Even if it is accidentally ejected onto the liquid, the liquid 107a is repelled and rolls onto the hole injection / transport layer 106. Thereby, the layer of the liquid 107a can be formed in close contact with the hole injection / transport layer 106.

  The amount of the liquid 107a is determined by the thickness of the R light emitting layer 108R to be formed, the concentration of the light emitting layer material in the liquid, and the like. Further, the liquid material 107a may be dropped on the same hole injection / transport layer 106 not only once but also in several times. In this case, the amount of ink droplets at each time may be the same, and the ink amount may be changed every time. Furthermore, ink droplets may be ejected not only to the same location on the hole injection / transport layer 106 but also to different locations within the hole injection / transport layer 106 each time.

  Thereafter, the liquid component of the liquid 107a is evaporated and dried to form a flat R light emitting layer 108R on the hole injection / transport layer 106 as shown in FIG. 6-5. The drying conditions can be, for example, a condition in which a pressure is set to about 133.3 Pa (1 Torr) at room temperature in a nitrogen atmosphere for 5 to 10 minutes, or a condition in which nitrogen is blown at 40 ° C. for 5 to 10 minutes. . Examples of other drying means include a far-infrared irradiation method and a high-temperature nitrogen gas spraying method. In the same manner, after applying the liquid material containing the G light emitting layer material and the B light emitting layer material, the second liquid material is applied and dried to form the G light emitting layer and the B light emitting layer. As shown in FIG. 6-6, a substrate on which three types of light emitting layers 108R, 108G, and 108B are formed.

  Here, as the light emitting layer material, polyphenylene vinylene derivatives, polyfluorene derivatives, polyvinyl carbazole, polythiophene derivatives, perylene dyes, coumarin dyes, rhodamine dyes, other low molecular organic EL materials soluble in benzene derivatives, polymers An organic EL material or the like can also be used. For example, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, quinacridone and the like can be used.

  As the nonpolar solvent, a benzene solvent such as cyclohexylbenzene, or a biphenyl solvent such as isopropylbiphenyl or dimethylbiphenyl can be used. As the liquid 107a, a solution in which these light emitting layer materials are dissolved in a nonpolar solvent can be used.

(6) Cathode Formation Step Next, in the cathode formation step, the cathode 109 is formed on the entire surface of the light emitting layers 108R, 108G, and 108B and the organic bank layer 102b. The cathode 109 may be formed by stacking a plurality of materials. For example, it is preferable to use a material having a small work function on the side close to the light emitting layer. For example, Ca, Ba or the like can be used. Depending on the material, it may be preferable to form a thin LiF layer. is there. Also, the upper side (sealing side) preferably has a higher work function than the lower side (light emitting layer side) cathode layer, and is preferably made of, for example, an Al film, an Ag film, a Mg / Ag laminated film, or the like. The thickness is preferably in the range of, for example, 100 to 1000 nm, particularly about 200 to 500 nm. These cathodes (cathode layers) are preferably formed by, for example, a vapor deposition method, a sputtering method, a CVD method, or the like. Particularly, the vapor deposition method can prevent the light emitting layers 108R, 108G, and 108B from being damaged by heat. Is preferable. Further, lithium fluoride may be formed only on the light emitting layers 108R, 108G, and 108B, or may be formed only on any one of the specific light emitting layers. In this case, the other light emitting layer is in contact with a cathode made of calcium. Further, a protective layer such as SiO, SiO ₂ or SiN may be provided on the reflective layer to prevent oxidation.

(7) Sealing process Finally, in the sealing process, a sealing material made of a thermosetting resin or an ultraviolet curable resin is applied to the entire surface of the cathode 109 to form the sealing layer 120. Further, a sealing substrate (not shown) is stacked on the sealing layer 120. The sealing step is preferably performed in an inert gas atmosphere such as nitrogen, argon, or helium. It is not preferable to perform in the atmosphere since defects such as pinholes are generated in the reflective layer because water or oxygen may enter the cathode 109 from the defective portion and the cathode 109 may be oxidized. In this way, an organic EL device as shown in FIGS. 6-7 is obtained.

[Color filter substrate manufacturing process]
Next, a method for manufacturing a color filter substrate using the thin film forming method of this embodiment will be described with reference to FIGS. FIG. 7 is a flowchart showing the manufacturing process of the color filter substrate, and FIG. 8 is a manufacturing process diagram of the color filter substrate. As shown in FIG. 7, the manufacturing process of the color filter substrate of the present embodiment includes (1) a black matrix forming process (S201), (2) a bank forming process (S202), and (3) a colored layer forming process ( S203) and (4) protective film forming step (S204).

(1) Black Matrix Formation Step In the black matrix formation step, a black matrix 202 is formed on the substrate 201 as shown in FIG. The black matrix 202 is formed of a laminate of metal chromium and chromium oxide, a resin matrix, or the like. A sputtering method, a vapor deposition method, or the like can be used to form the black matrix 502 made of a metal thin film. In addition, a gravure printing method, a photoresist, a thermal transfer method, or the like can be used to form a black matrix made of a resin thin film.

(2) Bank formation process In the bank formation process, a bank is formed in a state of being superimposed on the black matrix 202. That is, first, as shown in FIG. 8B, a resist layer 204 made of a negative transparent photosensitive resin is formed so as to cover the substrate 201 and the black matrix. Then, an exposure process is performed with the upper surface covered with a mask film 205 formed in a matrix pattern shape. Further, as shown in FIG. 8C, the bank 203 is formed by patterning the resist layer 204 by etching the unexposed portion of the resist layer 204. When a black matrix is used for the resin black, it is possible to use both the black matrix and the bank.

  The bank 203 and the black matrix 202 therebelow serve as a partition wall 207b that partitions each pixel region 207a. In the subsequent colored layer forming step, colored layers (film forming portions) 208R, 208G, and 208B are formed by a droplet discharge head. The landing area of the liquid material is defined when forming the.

  The filter substrate 200A is obtained through the above black matrix forming step and bank forming step. In the present embodiment, as the material of the bank 203, a resin material whose surface is lyophobic (hydrophobic) is used. Since the surface of the substrate (glass substrate) 201 is lyophilic (hydrophilic), in the colored layer forming step described later, the droplets into the pixel region 207a surrounded by the bank 203 (partition wall portion 207b). The landing accuracy is improved.

(3) Colored layer forming step Next, in the colored layer forming step, an R colored layer 208R, a G colored layer 208G, and a B colored layer 208B are sequentially formed by an inkjet method. Here, only the method for forming the R light emitting layer will be described, and descriptions of the G light emitting layer and the B light emitting layer will be omitted. In the colored layer forming step, the droplet discharge device 1 is disposed in a high-pressure chamber (not shown), and the liquid 208a containing the R colored layer material (thin film forming material) is discharged into the pixel region 207a in a high-pressure atmosphere. Thereafter, a drying process and a heat treatment are performed with a drying apparatus to form the R light emitting layer 108R. Here, it is desirable that the high-pressure atmosphere is set to be equal to or higher than the vapor pressure of the solvent or dispersion medium of the liquid 208a in order to prevent drying unevenness of the liquid 208a.

  Specifically, as shown in FIG. 8-4, in the droplet discharge head 32, the liquid 208a containing the R colored layer forming material (thin film forming material) is surrounded by the partition wall 207b. To discharge. Thereafter, a drying process and a heat treatment are performed by a drying apparatus to evaporate the liquid material 208a, thereby forming an R colored layer 208R as shown in FIG. 8-5. In the same manner, the G colored layer 208G and the B colored layer 208G are formed to form a substrate on which three types of colored layers 208R, 208G, and 208B are formed as shown in FIG. 8-6.

(4) Protective film forming step In the protective film forming step, as shown in FIG. 8-7, protection is performed so as to cover the upper surface of the substrate 201, the partition wall portion 207b, and the R, G, B colored layers 208R, 208G, 208B. A film 209 is formed. That is, after the protective film liquid is applied to the entire surface of the substrate 201 on which the R, G, and B colored layers 208R, 208G, and 208B are formed, the protective film 209 is formed through a drying process.

(Application to electro-optical devices)
The thin film forming method of the present invention can be used for manufacturing various electro-optical devices in addition to the organic EL device and the liquid crystal display device. For example, a liquid crystal display device, an organic TFT display device, a plasma display device, and an electrophoretic display. It can be widely applied to devices, electron emission display devices (Field Emission Display, Surface-Conduction Electoron-Emitter Display, etc.), LED (Light Emitting Diode) display devices, electrochromic glass devices, electronic paper devices and the like.

(Application to electronic equipment)
Next, specific examples of electronic devices to which the electro-optical device according to the invention can be applied will be described with reference to FIG. FIG. 9A is a perspective view illustrating an example in which the electro-optical device according to the invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) 300. As shown in the figure, the personal computer 300 includes a main body 302 including a keyboard 301 and a display unit 303 to which the electro-optical device according to the invention is applied. FIG. 9B is a perspective view illustrating an example in which the electro-optical device according to the invention is applied to the display unit of the mobile phone 400. As shown in the figure, the cellular phone 400 includes a plurality of operation buttons 401, a receiving mouth 402, a mouthpiece 403, and a display unit 404 to which the electro-optical device according to the invention is applied.

  The electro-optical device according to the present invention includes a portable information device called PDA (Personal Digital Assistants), a personal computer, a workstation, a digital still camera, an in-vehicle monitor, a digital video camera, in addition to the above-described cellular phone and notebook computer. Can be widely applied to electronic devices such as liquid crystal televisions, viewfinder type, monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, video phones, and POS terminals. .

  The electro-optical device according to the present invention includes an organic EL electroluminescence, a liquid crystal display device, an organic TFT display device, a plasma display device, an electrophoretic display device, an electron emission display device (Field Emission Display, Surface-Conduction Electoron-Emitter Display, etc.) It can be widely used in electro-optical devices such as LED (light emitting diode) display devices, electrochromic glass devices, and electronic paper devices. The electronic device according to the present invention includes a mobile phone, a portable information device called PDA (Personal Digital Assistants), a portable personal computer, a personal computer, a workstation, a digital still camera, an in-vehicle monitor, a digital video camera, and a liquid crystal display. It can be widely used in electronic devices such as televisions, viewfinder type, monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, video phones, and POS terminals.

1 is a schematic perspective view illustrating an overall configuration of a droplet discharge device according to an embodiment. FIG. 3 is an exploded perspective view of a droplet discharge head according to an embodiment. Sectional drawing of the droplet discharge head which concerns on an Example. The figure for demonstrating the coating method of the liquid body by the droplet discharge apparatus which concerns on an Example. The flowchart which shows the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the organic electroluminescent apparatus which concerns on an Example. The flowchart which shows the manufacturing process of the color filter substrate concerning an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. Explanatory drawing for demonstrating the manufacturing process of the color filter substrate which concerns on an Example. 1 is a perspective view of a personal computer equipped with an electro-optical device according to an embodiment. 1 is a perspective view of a mobile phone including an electro-optical device according to an example. Explanatory drawing for demonstrating a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet apparatus, 11 Liquid body, 12 Droplet discharge head, 13 Droplet discharge means, 14 Moving means, 15 Control means, 16 Substrate stage, 17 Head support part 18 Stage, 19 Stage drive part, 20 (theta) axis stage, 21 Stage, 22 Tube, 23 Tank, 32 Droplet ejection head, 41 Nozzle plate, 42 Vibration plate, 43 Partition member (reservoir plate), 44 Space, 45 Liquid reservoir, 46 Supply port, 47 Nozzle, 47a Nozzle hole, 48 Piezoelectric Element (piezo element), 49 electrodes, 100 substrate, 101 transparent electrode, 102 bank part (partition), 102a inorganic bank layer, 102b organic bank layer, 103, 103a, 103b opening, 105a, 105b liquid, 105 PEDT film 106 hole injection / transport layer, 107a, 107b, 10 7c Liquid, 108R, 108G, 108B Light emitting layer, 109 Cathode, 120 Sealing layer, 201 Substrate, 202 Black matrix, 208R, 208G, 208B Colored layer, 300 Personal computer, 301 Keyboard, 302 Main body, 303 Display, 400 mobile phone, 401 operation button, 402 earpiece, 403 mouthpiece, 404 display unit

Claims (9)

In a thin film forming method of forming a thin film by an inkjet method on a substrate application region,
A thin film forming method, wherein a liquid material in which a thin film forming material is dissolved or dispersed in a solvent or a dispersion medium is applied to the application region by an inkjet method under a high-pressure atmosphere.   The thin film forming method according to claim 1, wherein the high-pressure atmosphere is an atmosphere having a pressure equal to or higher than a vapor pressure of the solvent or the dispersion medium.   The thin film forming method according to claim 1 or 2, wherein the solvent or dispersion medium is a low boiling point solvent or dispersion medium.   The thin film forming method according to claim 1, wherein the coating region is subjected to a lyophilic process.   The thin film forming method according to claim 1, wherein the application region is a region defined by a partition wall.   The thin film forming method according to claim 1, wherein the thin film is a light emitting layer or a hole / injection transport layer of an organic EL device.   The said thin film is a color filter, The thin film formation method as described in any one of Claims 1-5 characterized by the above-mentioned. In a droplet discharge device that discharges a liquid material from a droplet discharge head,
A liquid droplet ejection apparatus, wherein a liquid material in which a thin film forming material is dissolved or dispersed is applied to a coating area of a substrate in a high pressure atmosphere by the liquid droplet ejection head.   A method of manufacturing an organic EL device, comprising: a thin film forming step of forming the thin film by the thin film forming method according to claim 1.

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