WO2013046608A1

WO2013046608A1 - Thin film forming method

Info

Publication number: WO2013046608A1
Application number: PCT/JP2012/005985
Authority: WO
Inventors: 啓裕鈴木; 智洋甲斐; 雅幸小谷
Original assignee: 凸版印刷株式会社
Priority date: 2011-09-29
Filing date: 2012-09-20
Publication date: 2013-04-04
Also published as: KR20140084002A; JPWO2013046608A1; CN103906576A; TW201321085A

Abstract

While the discharge ports of a plurality of nozzles (23) are brought close to an image receiving layer film (28) which is a discharge inspection recording body and the image receiving layer film (28) and the plurality of nozzles (23) are moved relative to each other, ink is discharged from the plurality of nozzles (23), and a test coating is carried out. Next, a line width measurement is carried out on tracks which are drawn by each of the nozzles (23) when the test coating is carried out. Next, the test coating and the line width measurement are repeated while the ink flow quantities which are supplied to the nozzles (23) are varied and a combination of flow quantities which are supplied to the nozzles (23) derived such that the line widths of the tracks which are drawn by each of the nozzles (23) are uniform. By discharging ink using the derived flow quantity combination, it is possible to keep the ink discharge quantities at a given level.

Description

Thin film formation method

The present invention relates to a thin film forming method, and more particularly to a thin film forming method that can be used for forming a functional layer of an organic electroluminescence (EL) element.

In recent years, a film forming technique using an ink jet method has attracted attention. The ink jet method can discharge a minute amount of ink to a desired position according to the resolution of the head to be used, so that it is easy to form a fine pattern or a thin film having a desired film thickness. It has the feature. Taking advantage of this feature, the inkjet method is used for manufacturing organic EL elements and color filters that require fine coating. In addition, a technique has been proposed in which a paste-like functional material is continuously discharged from a nozzle having a single or a plurality of fine discharge ports to form a predetermined pattern on a substrate.

When the inkjet method or the nozzle method is applied to the manufacture of an organic EL element, a required amount of EL material is dispersed or dissolved in a predetermined solvent to form an ink, thereby making the EL more than the vapor deposition method or the sputtering method. There is an advantage that the utilization efficiency of the material can be improved.

However, in the case of coating with one nozzle in the nozzle method, the tact time becomes longer as the substrate size becomes larger, so the productivity is lowered. By using multiple nozzles, the tact time can be shortened and productivity can be increased. However, if the discharge amount of each nozzle varies, the thickness of the functional film to be formed varies. , Causing uneven emission.

As a method of adjusting the discharge amount of each of the plurality of nozzles, the functional liquid stored in a single supply source is branched and supplied to the plurality of nozzles, and simultaneously applied onto the substrate from each nozzle, There has been proposed a method of applying a functional liquid to a plurality of positions simultaneously. In order to discharge an accurate discharge amount from the nozzle, it is necessary to measure and manage the actual discharge flow rate discharged from the nozzle. For example, the actual discharge flow rate discharged from the nozzle is discharged from the nozzle into a predetermined container, and is measured by the weight in the container with respect to the unit discharge time (see, for example, Patent Document 1).

JP 2006-205024 A

However, in the case of a coating apparatus that discharges simultaneously from a plurality of nozzles, it is necessary to measure the actual discharge flow rate described above for each nozzle system and derive the respective relational expressions. Moreover, in order to derive a highly accurate relational expression, it is necessary to measure actual discharge flow rates at a plurality of points with different flow rates for one nozzle system. In addition, when changing the functional liquid to be applied in a coating apparatus having a plurality of nozzles, it is necessary to measure the actual discharge flow rate even after the functional liquid is changed, so that the number of man-hours for flow management of the coating apparatus increases. In addition, when the actual discharge flow rate measurement time of the coating apparatus becomes longer, the actual discharge flow rate may fluctuate due to evaporation of the solvent in the functional liquid discharged into the container, making it difficult to accurately measure the actual discharge flow rate. Sometimes.

Therefore, an object of the present invention is to provide a thin film forming method that makes it easy to adjust the discharge amount of liquid discharged from each of a plurality of nozzles.

The present invention relates to a thin film forming method for forming a thin film by applying ink to a plurality of regions partitioned on a substrate using a plurality of nozzles. In the thin film forming method according to the present invention, the discharge ports of the plurality of nozzles are brought close to the surface of the test substrate, and the ink is discharged from the plurality of nozzles while the test substrate and the plurality of nozzles are relatively moved. A test application step, a step of measuring a line width of a locus drawn by each of the plurality of nozzles during the test application, and a test application while changing a flow rate of ink supplied to each of the plurality of nozzles. Repeating the step of measuring and the step of measuring the line width to obtain a combination of the flow rates of ink supplied to each of the plurality of nozzles such that the line width of the trajectory drawn by each of the plurality of nozzles is the same; Using a combination of flow rates obtained in the step of obtaining a combination of flow rates while moving a plurality of nozzles close to the surface of the substrate and relatively moving the substrate and the plurality of nozzles, And a step of ejecting the ink onto a substrate from the number of nozzles.

Alternatively, in the thin film forming method according to the present invention, the discharge ports of the plurality of nozzles are brought close to the surface of the test substrate, and ink is discharged from the plurality of nozzles while the test substrate and the plurality of nozzles are relatively moved. The step of performing test coating, the step of measuring the line width of the trajectory drawn by each of the plurality of nozzles at the time of test coating, while changing the relative movement speed of the plurality of nozzles and the test substrate, Repeating the test application step and the step of measuring the line width, obtaining a combination of relative movement speeds of the plurality of nozzles such that the line width of the trajectory drawn by each of the plurality of nozzles is the same, and While moving a plurality of nozzles and the substrate relative to each other at the relative movement speed obtained in the step of obtaining a combination of relative movement speeds by bringing a plurality of nozzles close to the surface of the substrate. And a step of ejecting ink from a plurality of nozzles onto a substrate.

According to the present invention, when a thin film is formed by applying ink using a plurality of nozzles, the discharge amount of each nozzle is adjusted based on the line width of the application mark applied to the test application part. The film thickness unevenness of the formed thin film can be reduced.

FIG. 1 is a cross-sectional view of an organic EL element substrate according to an embodiment. FIG. 2 is a schematic view of a thin film shaper using a nozzle coating method. FIG. 3 is a detailed view of the cross section of the nozzle head. FIG. 4 is a schematic diagram of the test ejection device. FIG. 5 is a graph showing the relationship between the line width and the flow rate (before adjustment). FIG. 6 is a graph showing the relationship between the line width and the flow rate (after adjustment). FIG. 7 is a graph showing the relationship between the speed and the discharge amount. FIG. 8 is a graph showing the relationship between the line width and the flow rate (before adjustment). FIG. 9 is a graph showing the relationship between the line width and the flow rate (after adjustment).

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the present invention is described based on an example in which an organic EL element substrate is manufactured using a nozzle coating device. However, the present invention is not limited to an organic EL, and constitutes a display screen of another display display. It can be suitably used to form an optical component. Examples of optical components other than organic EL include color filters, circuit boards, thin film transistors, microlenses, and biochips.

Hereinafter, the pattern forming body of the hole injection layer, the hole transport layer, and the organic light emitting layer included in the organic EL element is collectively referred to as a functional layer, and this functional layer is formed using the coating apparatus according to the above embodiment. The case will be described with reference to FIG.

(Preparation of substrate)
The organic EL element is formed on the substrate. A translucent substrate 1 is preferably used as the substrate. As the translucent substrate 1, a glass substrate or a plastic film or sheet can be used. When a plastic film is used, it is possible to wind up at the time of manufacturing a polymer EL element, and a display panel can be provided at a low cost. Examples of the plastic film that can be used include polyethylene terephthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, and polycarbonate. These films are composed of metal oxides such as silicon oxide that exhibit water vapor barrier properties and oxygen barrier properties, oxynitrides such as silicon nitride, polyvinylidene chloride, polyvinyl chloride, ethylene-vinyl acetate copolymer saponified products. It is preferable to provide a barrier layer as necessary.

(Production of pixel electrode)
On the translucent substrate 1, a patterned pixel electrode 2 is provided as an anode. As the material of the pixel electrode 2, transparent electrode materials such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), tin oxide, zinc oxide, indium oxide, and aluminum oxide composite oxide can be used. Of these electrode materials, ITO is preferably used because of its low resistance, solvent resistance, and transparency. ITO is formed on the translucent substrate by sputtering, and is patterned by photolithography to form line-shaped pixel electrodes 2.

(Production of partition walls)
After the line-shaped pixel electrode 2 is formed, a partition wall 3 is formed between adjacent pixel electrodes 2. The partition walls 3 are provided in a lattice shape or a stripe shape on the substrate and the inspection substrate. Each region surrounded by the partition walls 3 becomes a discharge region that is a target for forming a thin film of ink by nozzle coating. The partition 3 is formed by a photolithography method using a photosensitive material. The photosensitive material for forming the partition wall 3 may be either a positive type resist or a negative type resist, but it must have insulating properties. If the partition 3 does not have sufficient insulation, a current flows to the adjacent pixel electrode through the partition and a display defect occurs. Specific examples include polyimide, acrylic resin, novolak resin, and fluorene, but are not limited thereto. Further, for the purpose of improving the display quality of the organic EL element, a light shielding material may be included in the photosensitive material. In addition, by adding an appropriate amount of an ink repellent such as a fluorine-containing compound or a silicon-containing compound to the partition wall material, an appropriate ink repellency can be provided.

The thickness (height) of the partition wall 3 according to this embodiment is preferably 0.5 to 5.0 μm. By providing the partition wall 3 between the adjacent pixel electrodes 2, it is possible to suppress the spreading of the hole transport ink printed on each pixel electrode, and to prevent the occurrence of a short circuit from the edge of the transparent conductive film. If the partition walls are too low, the effect of preventing a short circuit may not be obtained, so care must be taken.

(Adjustment of hole injection layer ink)
The ink adjustment for forming the hole injection layer 4 will be described. The volume resistivity of the formed hole injection layer 4 is preferably 1 × 10 ⁶ Ω · cm or less from the viewpoint of light emission efficiency. Hole injection materials include metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine, metal-free phthalocyanines, quinacridone compounds, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N , N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine, N, N'-di (1-naphthyl) -N, N'- Aromatic amine low molecular hole injection / transport materials such as diphenyl-1,1'-biphenyl-4,4'-diamine, polymer hole injection materials such as poly (p-phenylene vinylene) and polyaniline, polythiophene oligomers The material can be selected from other known hole injection materials.

Examples of the solvent for dissolving or dispersing the hole injection material include halogen solvents such as chloroform, dichloromethane, dichloroethane, trichloroethylene, ethylene chloride, tetrachloroethane, chlorobenzene, N-methyl-2-pyrrolidone (NMP), dimethyl Polar solvents such as aprotic polar solvents such as formamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and alkoxy alcohols such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether Etc.

(Preparation of hole transport layer ink)
The ink adjustment for forming the hole transport layer 5 will be described. Examples of the hole transporting substance include poly (N-vinylcarbazole) (hereinafter also referred to as PVK), poly (para-phenylene vinylene), carbazole biphenyl (hereinafter also referred to as CBP), N, N′—. Diphenyl-N, N′-bis (1-naphthyl) -1,1′-biphenyl-4,4′-diamine (hereinafter also referred to as NPD), N, N′-diphenyl-N, N′-bis (3 -Methylphenyl) -1,1'-biphenyl-4,4'-diamine (hereinafter also referred to as TPD), 4,4'-bis (10-phenothiazinyl) biphenyl, 2,4,6-triphenyl- Examples thereof include 1,3,5-triazole, polyfluorene derivatives, and a copolymer of triphenylamine and fluorene.
Examples of the solvent for the functional ink that forms the hole transport layer include siemen, tetralin, cumene, decalin, durene, cyclohexylbenzene, dihexylbenzene, tetramethylbenzene, and dibutylbenzene.

(Preparation of organic light emitting layer ink)
The ink adjustment for forming the organic light emitting layer 6 will be described. The organic light emitting layer 6 is a layer that emits light when an electric current is applied. Examples of the organic light-emitting material for forming the organic light-emitting layer 6 include, for example, coumarin-based, perylene-based, pyran-based, anthrone-based, porphyrin-based, quinacridone-based, N, N′-dialkyl-substituted quinacridone-based, naphthalimide-based, N, N '-Diaryl-substituted pyrrolopyrrole, iridium complex and other luminescent dyes dispersed in polymers such as polystyrene, polymethylmethacrylate, polyvinylcarbazole, polyarylene, polyarylene vinylene and polyfluorene Examples include polymer materials. Examples of the solvent for the functional ink that forms the organic light emitting layer 6 include siemen, tetralin, cumene, decalin, durene, cyclohexylbenzene, dihexylbenzene, tetramethylbenzene, and dibutylbenzene.

(Formation of hole injection layer)
A functional ink containing a hole injection material is ejected to the substrate 1 on which the partition walls 3 are formed by a nozzle coating method described later, thereby forming a hole injection layer 4.

(Formation of hole transport layer)
After the hole injection layer 4 is formed, the hole transport layer 5 is formed by discharging a functional ink containing a hole transport material by a nozzle coating method described later.

(Formation of organic light emitting layer)
After the hole transport layer 5 is formed, a functional ink containing an organic light emitting material is discharged by a nozzle coating method described later to form the organic light emitting layer 6.

(Formation of cathode layer)
After the organic light emitting layer 6 is formed, the cathode layer 7 is formed in a line pattern orthogonal to the line pattern of the pixel electrode 2. As the material of the cathode layer 7, a material corresponding to the light emission characteristics of the organic light emitting layer 6 can be used. For example, a simple metal such as lithium, magnesium, calcium, ytterbium, and aluminum or a stable metal such as gold and silver can be used. And alloys thereof. Alternatively, a conductive oxide such as indium, zinc, or tin can be used. Examples of the method for forming the cathode layer include a method using a vacuum vapor deposition method using a mask.

(Description of sealing process)
Finally, in order to protect these organic EL constituents from external oxygen and moisture, a glass cap 8 and an adhesive 9 are hermetically sealed to obtain an organic EL display panel. As a sealing method, any method may be used as long as the organic EL structure can be protected from external oxygen and moisture. Moreover, when the translucent board | substrate 1 has flexibility, you may seal using a sealing agent and a flexible film.

In the organic EL device according to this embodiment, the hole injection layer 4, the hole transport layer 5, and the organic light emitting layer 6 are disposed between the pixel electrode 2 that is an anode and the cathode layer 7 in order from the anode layer side. Although it is a laminated structure, in addition to the hole transport layer 5 and the organic light emitting layer 6, layers such as a hole blocking layer, an electron transport layer, and an electron injection layer are provided as needed between the anode layer and the cathode layer. A laminated structure can be taken. Moreover, when forming these layers, the formation method similar to the organic light emitting layer 6 is applicable.

(Configuration of nozzle coating device)
Hereinafter, a configuration example of a nozzle coating apparatus used for forming a hole injection layer, a hole transport layer, and an organic light emitting layer will be described with reference to FIG. 2, but the present invention is not limited to this.

2 includes an ink supply tank 10, an ink supply tube 12, a flow meter 16, a flow control valve 15, and a nozzle head 13. The ink 11 filled in the ink supply tank 10 is supplied to the nozzle head 13 through the ink supply tube 12. Supply of the ink 11 to the nozzle head 13 is performed by pressurizing the inside of the ink supply tank 10 with the pressurizer 14 and pushing out the ink 11 from the ink supply tank 10. Between the ink supply tank 10 and the nozzle head 13, there are a flow rate control valve 15 for controlling the discharge amount of the ink 11 and a flow meter 16 for measuring the flow rate of the ink 11 supplied to the nozzle head 13. Has been placed. Since the flow rate control valve 15 is controlled based on information from the flow meter 16 (that is, ink flow rate) and can adjust the ink flow rate, a stable desired ink flow rate can be obtained. When a plurality of nozzle heads 13 are provided in the nozzle coating device, a plurality of sets of configurations from the nozzle head 13 to the ink supply tank 10 are provided.

Furthermore, the nozzle coating device includes a table 17 and an operation stage 19 which is disposed on the table 17 and is movable on the table 17 in the X direction and the Y direction perpendicular thereto. By moving the movable stage 19 in the Y direction or Y ′ direction (or X direction or X ′ direction) while discharging the ink 11 from the discharge port of the nozzle head 13, the nozzle 11 is continuously arranged on the movable stage 19. A coating film can be formed on the translucent substrate 18. For example, a translucent substrate 18 in which a plurality of pixel formation regions extending in parallel to each other in the X direction are provided in a stripe shape is disposed on a movable stage 19, and the movable stage 19 and the nozzle head 13 are relative to each other in the Y direction. Move to. At this time, based on the positional information of the movable stage 19 and the nozzle head 13, the movement of the movable stage 19 and the nozzle head 13 is synchronized, and R (Red), G (Green), or B (Blue) 1 The ink 11 is continuously applied to the pixel formation region of the book to form a coating film. And after forming a coating film in one pixel formation area of R, G, or B, the movable stage 19 and the nozzle head 13 are relatively moved to a X direction, and a coating film is formed in the following pixel formation area .

Next, the nozzle head will be described with reference to the sectional view of the nozzle head in FIG. The ink 11 enters a cylindrical or cuboid case 22 made of SUS (stainless steel) or the like from the ink supply tube 12. The case 22 is generally made of metal, but any case having ink resistance may be used. The inside of the case 22 is a manifold, and the liquid column 25 is discharged from the nozzle 23 having a minute hole having a diameter of about 5 to 20 microns to the translucent substrate 18. The nozzle is generally a film of polyimide or the like, but any nozzle can be used as long as it can accurately make a hole.

In consideration of nozzle clogging and flight bending due to ink drying, it is preferable that ink ejected from the nozzles be ejected continuously. For this reason, a portion that is not desired to be ejected may be masked or a dummy pattern may be provided, but any method may be used as long as there is no problem as a panel.

(Configuration of test application device)
FIG. 4 shows a schematic configuration of a test coating apparatus that performs the test coating of the present invention.

The test coating apparatus shown in FIG. 4 includes an image receiving layer film 28, a line width inspection unit 34 for optically capturing information of an image for line width inspection recorded on the image receiving layer film 28, and a line width inspection unit 34. An image information processing unit 32 for inspecting the line width from the image information taken in, a film unit 36 for feeding and winding the image receiving layer film 28, and a control unit (not shown) for controlling these operations. At least).

The image-receiving layer film 28 is a recording medium for line width inspection for producing a locus-like line width inspection image 35 drawn by ejecting ink from a plurality of nozzles. As the image receiving layer film 28, a commercially available ordinary film can be used. For example, a PET (polyethylene terephthalate) film can be used as a transparent film, and an image-receiving layer provided with a coating layer in which fine pigments are uniformly dispersed can be used. What is necessary is just to select suitably according to conditions, such as.

The line width inspection image 35 recorded on the image receiving layer film 28 is moved by the drive roller 37 to a place where the line width inspection section 34 is located. In the line width inspection unit 34, the line width inspection camera 27 captures the line width inspection image as image information and transfers the image information to the image information processing unit 32. When the camera 27 captures the information of the inspection image, the illumination 29 is turned on to illuminate the inspection image recorded on the image receiving layer film, thereby adding contrast and clearly recognizing the shape of the inspection image. Can be taken in. The illumination 29 can be installed on the camera side from the image receiving layer film, or the camera 27 can capture an image using only external light. In addition, even when the inspection image recorded on the image receiving layer film 28 is fine, it can be handled by appropriately selecting the resolution, viewing angle, etc. of the optical camera of the image information detection unit. It is.

The gap between the image receiving layer film 28 and the nozzle is set to be equal to the gap between the substrate and the nozzle when the substrate is placed on the stage of the nozzle coating apparatus. Further, the test coating device is installed so that the driving direction of the image receiving layer film is perpendicular to the driving direction of the nozzle of the nozzle coating device. The coating device and the test coating device are installed adjacent to each other. Moreover, when it is non-ejection when test-applying, it discharges again and it coats. That is, non-ejection inspection can be performed at the same time.

(Discharge rate adjustment method)
Next, a method for adjusting the discharge amount from the line width measurement result in the test coating apparatus will be described. When the flow meter values are discharged from a plurality of nozzles, the actual discharge amount actually discharged from each nozzle is slightly different. This is because the nozzle diameters of the nozzles are different and the accuracy of the flowmeter is different for each apparatus.

Therefore, in order to adjust the discharge amount of each nozzle, the relationship between the line width and the flow rate is first grasped. A line width inspection image is created by aligning the flow rate of each nozzle, and line width data of each nozzle is acquired. By repeating it at a plurality of flow rates, the relationship between the flow rate of each nozzle and the line width is obtained.

Fig. 5 shows the line width of each nozzle when three nozzles are used and the flow rate is applied at five levels a1 to a5. As shown in FIG. 5, the line width is usually different even if the flow rate is uniform for each nozzle. Next, from the relationship between the flow rate of each nozzle and the line width, the flow rate is adjusted so that the target line width is obtained. In order to align the line widths of the

nozzles

2 and 3 with the line width of the nozzle 1, an approximate straight line between the flow rate and the line width of each nozzle is obtained. From the approximate straight line, the flow rate is calculated so that the line widths of the

nozzles

2 and 3 are the same as the line width of the nozzle 1. By adjusting the flow rate of each nozzle, the line widths of the

nozzles

2 and 3 can be matched with the line width of the nozzle 1 as shown in FIG. Since the line width and the discharge amount are in a proportional relationship, if the line width is equal, the discharge amount is equal.

There are a method for adjusting the flow rate described above as a method for adjusting the line width and a method for adjusting at a speed at which the nozzle is moved relative to the substrate. When the flow rate is fixed and the speed is changed, the discharge amount and the speed indicate a power function relationship. Therefore, the line width can be adjusted by changing the speed, as in the case where the line width is adjusted by the flow rate. The relationship between speed and flow rate is shown in FIG. When the line width is adjusted according to the relative speed between the nozzle and the substrate, each of the plurality of nozzles is configured to be independently movable at a different speed. In the test coating apparatus, a plurality of line width inspection images are created while changing the relative movement speed of each nozzle, and the relationship between the relative speed of each nozzle and the line width as shown in FIG.

In this embodiment, the hole injection layer, the hole transport layer, and the organic light emitting layer are formed by the nozzle coating method, but it is not necessary to form all these layers by the nozzle coating method.

Next, examples in which the present invention is specifically implemented will be described.

A pixel electrode was formed by forming an ITO (indium-tin oxide) thin film on a 3-inch diagonal glass substrate by sputtering and patterning the ITO film by photolithography and etching with an acid solution. . The line pattern of the pixel electrode was a pattern in which about 590 lines were formed in about 7.6 mm square with a line width of 70 μm and a space of 60 μm.

Next, an insulating layer was formed as follows. First, a polyimide resist material was spin-coated on the entire surface of a glass substrate on which pixel electrodes were formed. The spin coating condition was rotated at 150 rpm for 5 seconds, and then rotated at 500 rpm for 20 seconds to form a single coating. The height of the insulating layer was 2.5 μm. A partition which is an insulating layer having a stripe pattern between pixel electrodes was formed by photolithography on the photoresist material applied to the entire surface.
This partition has ink repellency.

Next, as the hole injection ink, using a mixture of polymer hole injection materials such as poly (p-phenylene vinylene) and polyaniline and propylene glycol monobutyl ether, the solid content concentration of the ink is 1.5%, the viscosity is An ink of 7 mPa · s was prepared.

The prepared hole injection ink was put in an ink supply tank. The hole injection ink in the ink supply tank is supplied to the nozzle head through the ink supply tube by pressurizing the ink supply tank. A flow rate control valve that controls the amount of ink ejected between the ink supply tank and the nozzle, and a flow meter for measuring the flow rate of ink flowing to the nozzle head are provided. Based on the information of the ink flow meter, By feeding back to the flow control valve and adjusting the flow rate, a stable desired ink flow rate can be obtained.

The positions of the nozzle head and the table are relatively fixed, and the above-described translucent substrate having the stripe pattern partition walls imparted with ink repellency was fixed to a movable stage. The above-mentioned movable stage can move on the above-mentioned table in the direction of Y or Y ′ in the vertical direction. Further, the nozzle head can move in the direction X or X ′ in the lateral direction orthogonal to the Y or Y ′ direction. By relatively moving the stage and the nozzle or the nozzle unit, it is possible to continuously form a coating film serving as a pixel in the pixel formation region of the substrate on the stage.

The ink enters the rectangular nozzle head made of stainless steel from the ink supply tube. The inside of the nozzle head is a manifold, and can be discharged in a vertical direction with respect to the translucent substrate from a polyimide film nozzle having a minute hole with a diameter of 8 microns. In this example, three nozzles were used.

With the ink ejected from the three nozzles, the test ejection device was adjusted so as to achieve the target line width. FIG. 8 shows the relationship between the flow rate before adjustment and the line width, FIG. 9 shows the relationship between the flow rate after adjustment and the line width, and Table 1 shows the flow rate and line width of each nozzle before and after adjustment.

Next, the hole injection layer was applied at the adjusted flow rate. By performing feedback control of the flow control valve using the information of the flow meter, the amount of ink ejected from the nozzles is maintained uniformly. Then, the hole injection layer was formed by putting the board | substrate after ink application | coating on a 200 degreeC hotplate for 30 minutes. Thereafter, it was confirmed that a hole injection layer having a desired film thickness was obtained by film thickness measurement.

Next, an ink having a solid content concentration of 4.0% and a viscosity of 10 mPa · s was prepared using a hole transport material made of a polyfluorene derivative and cyclohexylbenzene.

Also when forming the hole transport layer, discharging was performed on the substrate on which the hole injection layer was formed with the same apparatus and procedure as when the hole injection layer was formed. After discharging, it was confirmed that a hole transport layer having a desired film thickness was obtained by firing at 200 ° C. for 1 hour in a nitrogen atmosphere to form a hole transport layer.

Next, using an RGB organic light emitting material composed of a poly (paraphenylene vinylene) derivative and cyclohexylbenzene, the solid content concentration of the ink is 7.0%, the R ink has a viscosity of 30 mPa · s, and the solid content concentration is 5.0%. A G ink having a viscosity of 5 mPa · s, a B ink having a solid content concentration of 6.0% and a viscosity of 20 mPa · s were prepared.

Also when forming the organic light emitting layer, discharging was performed on the substrate on which the hole transport layer was formed by the same apparatus and procedure as those for forming the hole injection layer described above. After discharge, an RGB organic light emitting layer was formed by baking at 130 ° C. for 30 minutes in a nitrogen atmosphere. Then, it confirmed that the organic light emitting layer of the desired film thickness was obtained by the film thickness measurement.

A cathode layer made of Ca and Al was formed thereon by mask vapor deposition using a resistance heating vapor deposition method in a line pattern orthogonal to the pixel electrode line pattern. Finally, in order to protect these organic EL constituents from external oxygen and moisture, they were hermetically sealed using a glass cap and an adhesive to produce an organic EL display panel.

There are an anode side extraction electrode and a cathode side extraction electrode connected to each pixel electrode in the periphery of the display portion of the organic EL element substrate obtained in this way, and these are obtained by connecting them to a power source. The lighting display of the obtained organic EL element substrate was confirmed, and the light emission state was checked. By matching the line widths of the ink ejected from each nozzle as in this example, an organic EL element substrate with a material utilization efficiency of 90% and no unevenness in light emission luminance could be obtained.

(Comparative Example 1)
As a comparative example, when ink is applied with the discharge amount from each nozzle as the value before adjustment in Table 1, a difference in film thickness occurs due to the difference in discharge amount for each nozzle in the light emission region of the panel, resulting in uneven brightness of light emission However, a high-quality organic EL element substrate could not be obtained.

The present invention can be used for manufacturing organic EL elements and the like.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 2 Pixel electrode 3 Partition 4 Hole injection layer 5 Hole transport layer 6 Organic light emitting layer 7 Cathode layer 8 Glass cap 9 Adhesive 10 Ink supply tank 11 Ink 12 Ink supply tube 13 Nozzle head 14 Pressurizer 15 Flow control valve 16 Flow meter 17 Table 18 Translucent substrate 19 Movable stage 22 Case 23 Nozzle 25 Liquid column 26 Head unit 27 Camera 28 Image receiving layer film (recording medium for ejection inspection)
DESCRIPTION OF SYMBOLS 29 Illumination 30 Feeding roller 31 Winding roller 32 Image information processing part 33 Line width display mechanism 34 Line width inspection part 35 Image for line width inspection 36 Film part 37 Drive roller

Claims

A thin film forming method for forming a thin film by applying ink to a plurality of regions partitioned on a substrate using a plurality of nozzles,
The test application is performed by ejecting ink from the plurality of nozzles while bringing the discharge ports of the plurality of nozzles close to the surface of the test substrate and moving the test substrate and the plurality of nozzles relative to each other. Steps,
Measuring the line width of the trajectory drawn by each of the plurality of nozzles during the test application;
While changing the flow rate of ink supplied to each of the plurality of nozzles, repeating the test application and measuring the line width, the line width of the trajectory drawn by each of the plurality of nozzles is Obtaining a combination of ink flow rates to be supplied to each of the plurality of nozzles so as to be the same;
Using the combination of flow rates obtained in the step of obtaining the combination of flow rates while bringing the plurality of nozzles close to the surface of the substrate and relatively moving the substrate and the plurality of nozzles, from the plurality of nozzles And a step of discharging ink onto the substrate.
A thin film forming method for forming a thin film by applying ink to a plurality of regions partitioned on a substrate using a plurality of nozzles,
The test application is performed by ejecting ink from the plurality of nozzles while bringing the discharge ports of the plurality of nozzles close to the surface of the test substrate and moving the test substrate and the plurality of nozzles relative to each other. Steps,
Measuring the line width of the trajectory drawn by each of the plurality of nozzles during the test application;
While changing the relative movement speed between the plurality of nozzles and the test substrate, the step of performing the test application and the step of measuring the line width are repeated, and the trajectory drawn by each of the plurality of nozzles Obtaining a combination of relative movement speeds of the plurality of nozzles such that the line widths are the same;
The plurality of nozzles are brought close to the surface of the base material, and the plurality of nozzles and the base material are relatively moved at the relative movement speed obtained in the step of obtaining a combination of the relative movement speeds. And a step of discharging ink onto the substrate from a nozzle.