Method for producing display device

Abstract

A step for forming a plurality of first electrodes (45) which constitute a light-emitting element layer comprises: a first step for forming a first electrode (45r) that corresponds to a first subpixel (Pr) by forming a first metal film (34) and a first transparent conductive film (35) in this order via a first film formation mask; a second step for forming a first electrode (45g) that corresponds to a second subpixel (Pg) by forming a second metal film (37) and a second transparent conductive film (38) in this order via a second film formation mask; and a third step for forming a first electrode (45b) that corresponds to a third subpixel (Pb) by forming a third metal film (40) and a third transparent conductive film (41) in this order via a third film formation mask.

Description

Display device manufacturing method

[0001] The present invention relates to a method for manufacturing a display device.

[0002] In recent years, self-luminous display devices using light-emitting elements such as organic electroluminescence (EL) elements have been attracting attention as alternatives to liquid crystal display devices. These self-luminous display devices include, for example, a base substrate, a thin film transistor (TFT) layer provided on the base substrate, a light-emitting element layer provided on the TFT layer and including a plurality of light-emitting elements, and a sealing film provided on the light-emitting element layer. Here, the light-emitting element includes, for example, a first electrode provided on the TFT layer, a light-emitting functional layer provided on the first electrode, and a second electrode provided on the light-emitting functional layer.

[0003] For example, Patent Document 1 discloses a display device including a cathode provided for each subpixel (as the first electrode), an anode provided above the cathode and common to a plurality of subpixels (as the second electrode), a light-emitting layer provided between the cathode and the anode, a first wiring provided in the same layer as the cathode, and a second wiring provided above the first wiring so as to overlap with the first wiring.

[0004] International Publication No. 2018 / 225183

[0005] Meanwhile, in self-luminous display devices such as organic EL display devices, a cavity structure has been proposed in which the optical path length is set to match the wavelength of each of the three primary colors, red, green, and blue, to improve light extraction efficiency through the optical resonance effect. However, if the thickness of the transparent conductive film constituting the first electrode is optimized for each color depending on the number of layers to form a cavity structure, the photolithography and etching processes may increase or become more complicated, and residues left during etching may cause a short circuit between the first electrode and the second electrode, resulting in a reduced manufacturing yield, so there is room for improvement.

[0006] The present invention has been made in consideration of these points, and its purpose is to form a cavity structure by a simple process while suppressing the occurrence of a short circuit between a first electrode and a second electrode.

[0007] In order to achieve the above object, a manufacturing method of a display device according to the present invention is a method for manufacturing a display device comprising: a base substrate; a thin-film transistor layer provided on the base substrate; and a light-emitting element layer provided on the thin-film transistor layer, in which a plurality of first electrodes, a plurality of light-emitting functional layers, and a common second electrode are sequentially stacked corresponding to a plurality of sub-pixels constituting a display area, the plurality of sub-pixels having first sub-pixels, second sub-pixels, and third sub-pixels that display colors different from one another, wherein the step of forming the plurality of first electrodes comprises: a first step of forming the first electrodes corresponding to the first sub-pixels by sequentially depositing a first metal film and a first transparent conductive film through a first deposition mask; a second step of forming the first electrodes corresponding to the second sub-pixels by sequentially depositing a second metal film and a second transparent conductive film through a second deposition mask; and a third step of forming the first electrodes corresponding to the third sub-pixels by sequentially depositing a third metal film and a third transparent conductive film through a third deposition mask.

[0008] According to the present invention, a cavity structure can be formed by a simple process while suppressing the occurrence of a short circuit between the first electrode and the second electrode.

[0009] FIG. 1 is a plan view showing a schematic configuration of an organic EL display device according to a first embodiment of the present invention. FIG. 2 is a plan view of a display region of the organic EL display device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of a display region of the organic EL display device according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a schematic configuration of a first electrode constituting the organic EL display device according to the first embodiment of the present invention. FIG. 5 is an equivalent circuit diagram of a TFT layer constituting the organic EL display device according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view of an organic EL layer constituting the organic EL display device according to the first embodiment of the present invention. FIG. 7 is a cross-sectional view showing a first step of a first electrode formation process in a manufacturing method for an organic EL display device according to the first embodiment of the present invention. FIG. 8 is a cross-sectional view showing a second step of a first electrode formation process in a manufacturing method for an organic EL display device according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view showing a third step of a first electrode formation process in a manufacturing method for an organic EL display device according to the first embodiment of the present invention.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0011] 1 to 9 show a first embodiment of a method for manufacturing a display device according to the present invention. In the following embodiments, an organic EL display device including an organic EL element layer is exemplified as a display device including a light-emitting element layer. FIG. 1 is a plan view showing a schematic configuration of an organic EL display device 100 according to this embodiment. FIGS. 2 and 3 are a plan view and a cross-sectional view of a display region D of the organic EL display device 100. FIG. 4 is a cross-sectional view showing a schematic configuration of a first electrode 45 constituting the organic EL display device 100. FIG. 5 is an equivalent circuit diagram of a TFT layer 30 constituting the organic EL display device 100. FIG. 6 is a cross-sectional view of an organic EL layer 47 constituting the organic EL display device 100.

[0012] 1 , the organic EL display device 100 includes, for example, a rectangular display area D for displaying an image, and a frame area F provided in a frame shape around the display area D. Note that, although the present embodiment illustrates a rectangular display area D, this rectangular shape also includes, for example, a substantially rectangular shape with arc-shaped sides, arc-shaped corners, or a shape with a notch in one of the sides.

[0013] 2, a plurality of sub-pixels P are arranged in a matrix in the display region D. Also, in the display region D, for example, a first sub-pixel Pr having a red light-emitting region Lr for displaying red, a second sub-pixel Pg having a green light-emitting region Lg for displaying green, and a third sub-pixel Pb having a blue light-emitting region Lb for displaying blue are provided adjacent to each other, as shown in FIG. 2. Note that in the display region D, one pixel is configured by three adjacent sub-pixels, the first sub-pixel Pr, the second sub-pixel Pg, and the third sub-pixel Pb, each having a red light-emitting region Lr, a green light-emitting region Lg, and a blue light-emitting region Lb, and displaying different colors.

[0014] A terminal portion T is provided to extend in one direction (Y direction in Fig. 1) at the end of the frame region F on the positive side in the X direction in Fig. 1. Furthermore, as shown in Fig. 1, between the display region D and the terminal portion T, that is, in the frame region F, on the display region D side of the terminal portion T, a folding portion B is provided to extend in one direction (Y direction in Fig. 1) that can be folded, for example, 180° (in a U-shape) with the Y direction in the drawing as the folding axis.

[0015] As shown in FIG. 3, the organic EL display device 100 includes a resin substrate 10 provided as a base substrate, a TFT layer 30 provided on the resin substrate 10, an organic EL element layer 60 provided as a light-emitting element layer on the TFT layer 30, and a sealing film 65 provided on the organic EL element layer 60.

[0016] The resin substrate 10 is made of, for example, polyimide resin.

[0017] As shown in FIG. 3 , the TFT layer 30 includes a base coat film 11 provided on a resin substrate 10, a plurality of first TFTs 9 a, a plurality of second TFTs 9 b, and a plurality of capacitors 9 c provided on the base coat film 11, and a protective insulating film 19 and a planarizing film 20 provided in that order on each of the first TFTs 9 a, each of the second TFTs 9 b, and each of the capacitors 9 c. As shown in FIG. 2 , the TFT layer 30 includes a plurality of gate lines 14 g extending parallel to one another in the X direction. As shown in FIG. 2 , the TFT layer 30 also includes a plurality of source lines 18 f extending parallel to one another in a direction intersecting (orthogonal to) the gate lines 14 g, i.e., in the Y direction. As shown in FIG. 2 , the TFT layer 30 also includes a plurality of power supply lines 18 g extending parallel to one another in the Y direction. As shown in FIG. 2 , each power supply line 18 g is adjacent to a corresponding source line 18 f. 5, the TFT layer 30 includes a first TFT 9a, a second TFT 9b, and a capacitor 9c in each subpixel P. In the TFT layer 30, as shown in Fig. 3, a base coat film 11, a semiconductor film that will become a semiconductor layer 12a (described later) and the like, a gate insulating film 13, a fourth metal film that will become a gate line 14g and the like, a first interlayer insulating film 15, a fifth metal film that will become an upper conductive layer 16c (described later) and the like, a second interlayer insulating film 17, a sixth metal film that will become a source line 18f, a power line 18g and the like, a protective insulating film 19, and a planarizing film 20 are stacked in this order on a resin substrate 10.

[0018] The base coat film 11, the gate insulating film 13, the first interlayer insulating film 15, the second interlayer insulating film 17, and the protective insulating film 19 are each made of an inorganic insulating film, such as a single layer film or a multilayer film, of silicon nitride, silicon oxide, silicon oxynitride, etc. At least the semiconductor layer 12a (12b) side of the base coat film 11 and the semiconductor layer 12a (12b) side of the gate insulating film 13 are made of, for example, a silicon oxide film.

[0019] 5, the first TFT 9a is electrically connected to the corresponding gate line 14g, source line 18f, and second TFT 9b in each subpixel P. Here, as shown in Fig. 3, the first TFT 9a includes a semiconductor layer 12a provided on a base coat film 11, a gate electrode 14a provided on the semiconductor layer 12a via a gate insulating film 13, and a source electrode 18a and a drain electrode 18b provided on a second interlayer insulating film 17 so as to be spaced apart from each other.

[0020] The semiconductor layer 12a and the semiconductor layer 12b described later are formed of a semiconductor film made of an oxide semiconductor such as an In-Ga-Zn-O system, and include a source region and a drain region that are defined to be spaced apart from each other, and a channel region that is defined between the source region and the drain region.

[0021] The gate electrode 14a is provided so as to overlap the channel region of the semiconductor layer 12a and is configured to control conduction between the source region and the drain region of the semiconductor layer 12a. Here, the gate electrode 14a is formed of a fourth metal film, similar to the gate line 14g.

[0022] 3, the source electrode 18a and the drain electrode 18b are electrically connected to the source region and the drain region of the semiconductor layer 12a, respectively, through contact holes formed in the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17. Here, the source electrode 18a and the drain electrode 18b are formed of a sixth metal film, similar to the source line 18f and the power supply line 18g.

[0023] 5, the second TFT 9b is electrically connected to the corresponding first TFT 9a, a power supply line 18g, and an organic EL element 50 (described later) in each subpixel P. Here, the second TFT 9b includes a semiconductor layer 12b provided on the base coat film 11, a gate electrode 14b provided on the semiconductor layer 12b via a gate insulating film 13, and a source electrode 18c and a drain electrode 18d provided spaced apart from each other on the second interlayer insulating film 17, as shown in FIG.

[0024] The gate electrode 14b is provided so as to overlap the channel region of the semiconductor layer 12b and is configured to control conduction between the source region and the drain region of the semiconductor layer 12b. Here, the gate electrode 14b is formed of a fourth metal film, similar to the gate line 14g.

[0025] 3, the source electrode 18c and the drain electrode 18d are electrically connected to the source region and the drain region of the semiconductor layer 12b, respectively, through contact holes formed in the stacked film of the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17. Here, the source electrode 18c and the drain electrode 18d are formed of a sixth metal film, similar to the source line 18f and the power line 18g.

[0026] In this embodiment, the semiconductor layers 12a and 12b are formed of a semiconductor film made of an oxide semiconductor, but the semiconductor layers 12a and 12b may be formed of a semiconductor film made of polysilicon such as LTPS (low temperature polysilicon). Furthermore, the TFT layer 30 may have a hybrid structure in which a TFT having a semiconductor layer made of polysilicon and a TFT having a semiconductor layer made of an oxide semiconductor are provided.

[0027] As shown in Fig. 5, the capacitor 9c is electrically connected to the corresponding first TFT 9a and power supply line 18g in each subpixel P. Here, as shown in Fig. 3, the capacitor 9c includes a lower conductive layer 14c formed of a fourth metal film, an upper conductive layer 16c formed of a fifth metal film, and a first interlayer insulating film 15 provided between the lower conductive layer 14c and the upper conductive layer 16c. Note that, as shown in Fig. 3, the upper conductive layer 16c is electrically connected to the power supply line 18g via a contact hole formed in the second interlayer insulating film 17.

[0028] The planarization film 20 has a flat surface in the display region D and is made of an organic resin material such as polyimide resin.

[0029] 3, the organic EL element layer 60 includes a plurality of third electrodes 31, a common first edge cover 32, a plurality of first electrodes 45, a common second edge cover 46, a plurality of organic EL layers 47, and a common second electrode 48, which are stacked in this order corresponding to a plurality of subpixels P. Here, in each subpixel P, the third electrode 31, the first electrode 45, the organic EL layer 47, and the second electrode 48 constitute an organic EL element 50, as shown in FIG. 3, and in the organic EL element layer 60, the plurality of organic EL elements 50 provided corresponding to the plurality of subpixels P are arranged in a matrix.

[0030] 3, the third electrode 31 is electrically connected to the drain electrode 18d of the second TFT 9b of each subpixel P through a contact hole formed in the protective insulating film 19 and the planarizing film 20. Here, the third electrode 31 is formed of a transparent conductive film such as an indium tin oxide (hereinafter also referred to as "ITO") film or an indium zinc oxide (hereinafter also referred to as "IZO") film, and has optical transparency. Note that, as shown in FIG. 4, the third electrode 31 is composed of a third electrode 31r provided in the first subpixel Pr, a third electrode 31g provided in the second subpixel Pg, and a third electrode 31b provided in the third subpixel Pb.

[0031] The first edge cover 32 is provided in a grid pattern over the entire display area D, and is provided so as to cover the peripheral edges of the third electrodes 31 (31r, 31g, 31b) as shown in Fig. 3. Here, the first edge cover 32 is made of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG (spin on glass) material.

[0032] The first electrode 45 has a function of injecting holes (positive holes) into the organic EL layer 47. It is more preferable that the first electrode 45 be formed of a material with a large work function in order to improve the efficiency of hole injection into the organic EL layer 47. Here, the first electrode 45 is formed of a laminated film in which, for example, a transparent conductive film such as an ITO film or an IZO film, a metal film such as a silver film or a silver alloy film, and a transparent conductive film such as an ITO film or an IZO film are laminated in this order, and has light reflectivity.

[0033] Specifically, as shown in FIG. 4, the first electrode 45 is composed of a first electrode 45r provided in the first sub-pixel Pr, a first electrode 45g provided in the second sub-pixel Pg, and a first electrode 45b provided in the third sub-pixel Pb.

[0034] As will be described later, the first electrode 45r is formed by depositing a fourth transparent conductive film 33, a first metal film 34, and a first transparent conductive film 35 in this order by sputtering through a first film deposition mask Ma (see FIG. 7) (see FIG. 4). As shown in FIG. 4, the first electrode 45r is provided on the third electrode 31r and is electrically connected to the third electrode 31r.

[0035] As will be described later, the first electrode 45g is formed by depositing a fifth transparent conductive film 36, a second metal film 37, and a second transparent conductive film 38 in this order by sputtering through a second film-deposition mask Mb (see FIG. 8) (see FIG. 4). As shown in FIG. 4, the first electrode 45g is provided on the third electrode 31g and is electrically connected to the third electrode 31g.

[0036] As will be described later, the first electrode 45b is formed by depositing a sixth transparent conductive film 39, a third metal film 40, and a third transparent conductive film 41 in this order by sputtering through a third film deposition mask Mc (see FIG. 9) (see FIG. 4). As shown in FIG. 4, the first electrode 45b is provided on the third electrode 31b and is electrically connected to the third electrode 31b.

[0037] Here, in the first electrode 45, as shown in FIG. 4 , the fourth transparent conductive film 33, the fifth transparent conductive film 36, and the sixth transparent conductive film 39 have the same thickness (e.g., approximately 5 nm to 15 nm). Also, in the first electrode 45, as shown in FIG. 4 , the first metal film 34, the second metal film 37, and the third metal film 40 have the same thickness (e.g., approximately 90 nm to 100 nm). Also, in the first electrode 45, as shown in FIG. 4 , the first transparent conductive film 35 (e.g., approximately 155 nm to 165 nm), the second transparent conductive film 38 (e.g., approximately 95 nm to 105 nm), and the third transparent conductive film 41 (e.g., approximately 60 nm to 70 nm) have different thicknesses. As a result, in the first electrode 45, as shown in FIG. 4 , the optical path length can be set for each of the first sub-pixel Pr, the second sub-pixel Pg, and the third sub-pixel Pb, and a cavity structure can be formed that improves light extraction efficiency by the optical resonance effect.

[0038] 3, the second edge cover 46 is provided in a grid pattern over the entire display area D, and is provided so as to cover the peripheral edge of the first electrode 45. Here, the second edge cover 46 is made of an inorganic insulating film, such as a single layer film or a multilayer film, made of silicon nitride, silicon oxide, silicon oxynitride, or the like.

[0039] 6 , the organic EL layer 47 is provided as a light-emitting functional layer, and includes a hole injection layer 1, a hole transport layer 2, a light-emitting layer 3, an electron transport layer 4, and an electron injection layer 5, which are stacked in this order on the first electrode 45. Note that, although the present embodiment illustrates a configuration in which each of the plurality of light-emitting functional layers is an organic EL layer 47, at least one of the plurality of light-emitting functional layers may be an organic EL layer 47.

[0040] The hole injection layer 1 is also called an anode buffer layer, and has the function of bringing the energy levels of the first electrode 45 and the organic EL layer 47 closer to each other and improving the efficiency of hole injection from the first electrode 45 to the organic EL layer 47. Examples of materials that form the hole injection layer 1 include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, phenylenediamine derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, and stilbene derivatives.

[0041] The hole transport layer 2 has a function of improving the efficiency of transporting holes from the first electrode 45 to the organic EL layer 47. Examples of materials constituting the hole transport layer 2 include porphyrin derivatives, aromatic tertiary amine compounds, styrylamine derivatives, polyvinylcarbazole, poly-p-phenylenevinylene, polysilane, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amine-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, hydrogenated amorphous silicon, hydrogenated amorphous silicon carbide, zinc sulfide, and zinc selenide.

[0042] The light-emitting layer 3 is a region into which holes and electrons are injected from the first electrode 45 and the second electrode 48, respectively, and where the holes and electrons recombine when a voltage is applied between the first electrode 45 and the second electrode 48. The light-emitting layer 3 is formed of a material with high luminous efficiency. Examples of materials that can be used for the light-emitting layer 3 include metal oxinoid compounds (8-hydroxyquinoline metal complexes), naphthalene derivatives, anthracene derivatives, diphenylethylene derivatives, vinylacetone derivatives, triphenylamine derivatives, butadiene derivatives, coumarin derivatives, benzoxazole derivatives, oxadiazole derivatives, oxazole derivatives, benzimidazole derivatives, thiadiazole derivatives, benzothiazole derivatives, styryl derivatives, styrylamine derivatives, bisstyrylbenzene derivatives, trisstyrylbenzene derivatives, perylene derivatives, perinone derivatives, aminopyrene derivatives, pyridine derivatives, rhodamine derivatives, aquidin derivatives, phenoxazone, quinacridone derivatives, rubrene, poly-p-phenylenevinylene, and polysilane.

[0043] The electron transport layer 4 has a function of efficiently transferring electrons to the light-emitting layer 3. Examples of materials constituting the electron transport layer 4 include organic compounds such as oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyanoanthraquinodimethane derivatives, diphenoquinone derivatives, fluorenone derivatives, silole derivatives, and metal oxinoid compounds.

[0044] The electron injection layer 5 has a function of bringing the energy levels of the second electrode 48 and the organic EL layer 47 closer to each other and improving the efficiency of electron injection from the second electrode 48 to the organic EL layer 47, and this function can reduce the driving voltage of the organic EL element 50. The electron injection layer 5 is also called a cathode buffer layer. Here, examples of materials constituting the electron injection layer 5 include lithium fluoride (LiF), magnesium fluoride (MgF ２ ), calcium fluoride (CaF ２ ), strontium fluoride (SrF ２ ), barium fluoride (BaF ２inorganic alkali compounds such as aluminum oxide (Al ２ O ３ ), strontium oxide (SrO), etc.

[0045] 3, the second electrode 48 is provided so as to cover each organic EL layer 47 and the second edge cover 46. The second electrode 48 also has the function of injecting electrons into the organic EL layer 47. The second electrode 48 is preferably made of a material with a small work function in order to improve the efficiency of electron injection into the organic EL layer 47. Here, the second electrode 48 is formed of a transparent conductive film such as an ITO film or an IZO film, and has high light transmittance.

[0046] 3 , the sealing film 65 is provided so as to cover the second electrode 48, and includes a first inorganic sealing film 61, an organic sealing film 62, and a second inorganic sealing film 63 laminated in this order on the second electrode 48, and has the function of protecting the organic EL layer 47 of the organic EL element 50 from moisture, oxygen, etc. Here, the first inorganic sealing film 61 and the second inorganic sealing film 63 are made of inorganic insulating films such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film. Furthermore, the organic sealing film 62 is made of an organic resin material such as an acrylic resin, an epoxy resin, a silicone resin, a polyurea resin, a parylene resin, a polyimide resin, or a polyamide resin.

[0047] The organic EL display device 100 described above is configured such that, in each subpixel P, a gate signal is input to the first TFT 9a via the gate line 14g to turn the first TFT 9a on, a data signal is written to the gate electrode 14b and capacitor 9c of the second TFT 9b via the source line 18f, and a current from the power supply line 18g corresponding to the gate voltage of the second TFT 9b is supplied to the organic EL element 50, causing the light-emitting layer 3 of the organic EL element 50 to emit light and display an image. Note that in the organic EL display device 100, even if the first TFT 9a is turned off, the gate voltage of the second TFT 9b is held by the capacitor 9c, so that light emission by the light-emitting layer 3 is maintained until a gate signal for the next frame is input.

[0048] Next, a method for manufacturing the organic EL display device 100 of this embodiment will be described. The method for manufacturing the organic EL display device 100 of this embodiment includes a TFT layer formation step, an organic EL element layer formation step including a first electrode formation step, and a sealing film formation step. Figures 7, 8, and 9 are cross-sectional views showing the first, second, and third steps of the first electrode formation step, respectively, in the method for manufacturing the organic EL display device 100.

[0049] <TFT Layer Formation Process> First, a silicon nitride film (thickness: about 50 nm) and a silicon oxide film (thickness: about 250 nm) are sequentially formed on a resin substrate 10 formed on a glass substrate by, for example, a plasma CVD (Chemical Vapor Deposition) method, thereby forming a base coat film 11.

[0050] Next, on the surface of the substrate on which the base coat film 11 has been formed, InGaZnO ４ After forming a semiconductor film made of an oxide semiconductor by depositing a film (thickness: about 30 nm) or the like, the semiconductor film is patterned to form the semiconductor layers 12a, 12b, and the like.

[0051] Thereafter, a silicon oxide film (about 150 nm thick) is formed by, for example, plasma CVD on the surface of the substrate on which the semiconductor layer 12a and the like are formed, thereby forming the gate insulating film 13.

[0052] Furthermore, a molybdenum film (about 260 nm thick) or the like is formed on the surface of the substrate on which the gate insulating film 13 is formed, for example, by sputtering, to form a fourth metal film, and then the fourth metal film is patterned to form gate electrodes 14a and 14b, a lower conductive layer 14c, a gate line 14g, etc.

[0053] Next, on the substrate surface on which the gate electrode 14a and the like are formed, a silicon nitride film (about 100 nm thick) and a silicon oxide film (about 100 nm thick) are sequentially formed by, for example, plasma CVD to form the first interlayer insulating film 15. Note that by heat treatment after the formation of the first interlayer insulating film 15, part of the semiconductor layer 12a (12b) is made conductive, and a source region, a drain region, and a channel region are formed in the semiconductor layer 12a (12b).

[0054] Thereafter, a molybdenum film (approximately 260 nm thick) or the like is formed on the substrate surface on which the first interlayer insulating film 15 is formed, for example, by sputtering, to form a fifth metal film, and then the fifth metal film is patterned to form the upper conductive layer 16c or the like.

[0055] Furthermore, a silicon oxide film (about 100 nm thick) and a silicon nitride film (about 100 nm thick) are sequentially formed on the substrate surface on which the upper conductive layer 16c and the like are formed, for example, by plasma CVD, thereby forming a second interlayer insulating film 17.

[0056] Subsequently, on the surface of the substrate on which the second interlayer insulating film 17 has been formed, the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17 are appropriately patterned to form contact holes.

[0057] Thereafter, a titanium film (thickness: about 10 nm), an aluminum film (thickness: about 300 nm), and a titanium film (thickness: about 50 nm) are sequentially formed by, for example, sputtering on the surface of the substrate on which the contact holes have been formed to form a sixth metal film, and then the sixth metal film is patterned to form source electrodes 18a and 18c, drain electrodes 18b and 18d, source line 18f, power line 18g, and the like.

[0058] Furthermore, a protective insulating film 19 is formed on the substrate surface on which the source electrode 18a and the like are formed by depositing a silicon oxide film (approximately 85 nm thick) and a silicon nitride film (approximately 400 nm thick), for example, by plasma CVD.

[0059] Next, an acrylic photosensitive resin film (about 2.5 μm thick) is applied to the substrate surface on which the protective insulating film 19 has been formed, for example, by spin coating or slit coating, and then the applied film is pre-baked, exposed to light, developed, and post-baked to form a planarization film 20 having contact holes.

[0060] Finally, the protective insulating film 19 exposed from the contact hole in the planarizing film 20 is removed so that the contact hole reaches the drain electrode 18d of the second TFT 9b.

[0061] In this manner, the TFT layer 30 can be formed.

[0062] <Organic EL element layer forming process> First, a transparent conductive film such as an ITO film (thickness: about 70 nm) is formed by, for example, a sputtering method on the surface of the substrate on which the TFT layer 30 has been formed in the TFT layer forming process, and then the transparent conductive film is patterned to form third electrodes 31 (31r, 31g, 31b) and the like (third electrode forming process).

[0063] Next, an acrylic photosensitive resin film (approximately 2.5 μm thick) is applied to the substrate surface on which the third electrode 31 etc. are formed, for example, by spin coating or slit coating, and then the applied film is pre-baked, exposed to light, developed and post-baked to form the first edge cover 32 (first edge cover formation process).

[0064] 7, a fourth transparent conductive film 33 (thickness: about 9 nm) such as an ITO film, a first metal film 34 (thickness: about 95 nm) such as an Ag film, and a first transparent conductive film 35 (thickness: about 160 nm) such as an ITO film are sequentially formed on the surface of the substrate on which the first edge cover 32 has been formed, using a first film-forming mask Ma, for example, by sputtering, to form a first electrode 45r corresponding to the first sub-pixel Pr (first step / first electrode forming step). Note that the first electrode forming step for forming the plurality of first electrodes 45 includes a first step, a second step, and a third step, which will be described later.

[0065] Furthermore, on the surface of the substrate on which the first electrode 45r has been formed, a fifth transparent conductive film 36 (thickness: approximately 9 nm) such as an ITO film, a second metal film 37 (thickness: approximately 95 nm) such as an Ag film, and a second transparent conductive film 38 (thickness: approximately 100 nm) such as an ITO film are sequentially formed by, for example, a sputtering method through a second film formation mask Mb, as shown in FIG. 8, to form a first electrode 45g corresponding to the second sub-pixel Pg (second process / first electrode formation process).

[0066] Next, on the surface of the substrate on which the first electrode 45g has been formed, a sixth transparent conductive film 39 (thickness: approximately 9 nm) such as an ITO film, a third metal film 40 (thickness: approximately 95 nm) such as an Ag film, and a third transparent conductive film 41 (thickness: approximately 65 nm) such as an ITO film are sequentially formed by, for example, a sputtering method through a third film formation mask Mc, as shown in FIG. 9, to form a first electrode 45b corresponding to the third sub-pixel Pb (third process / first electrode formation process).

[0067] Then, an inorganic insulating film such as a silicon nitride film (thickness: approximately 300 nm) is formed on the substrate surface on which the first electrode 45b is formed, for example, by plasma CVD, and the inorganic insulating film is patterned to form the second edge cover 46 (second edge cover formation process).

[0068] Furthermore, on the surface of the substrate on which the second edge cover 46 is formed, a hole injection layer 1, a hole transport layer 2, an emissive layer 3, an electron transport layer 4, and an electron injection layer 5 are sequentially formed, for example, by vacuum deposition, to a thickness of approximately several tens of nanometers to 50 nanometers, to form an organic EL layer 47 (organic EL layer formation process).

[0069] Finally, a transparent conductive film such as an ITO film (thickness: about 100 nm) is formed by sputtering using a mask on the surface of the substrate on which the organic EL layer 47 is formed, to form a second electrode 48 (second electrode formation process).

[0070] In this manner, the organic EL element layer 60 can be formed.

[0071] <Sealing film forming process> First, an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film is formed by plasma CVD using a mask on the surface of the substrate on which the organic EL element layer 60 has been formed in the organic EL element layer forming process, thereby forming a first inorganic sealing film 61.

[0072] Subsequently, an organic resin material such as an acrylic resin is deposited by, for example, an inkjet method on the surface of the substrate on which the first inorganic sealing film 61 has been formed, to form an organic sealing film 62 .

[0073] Furthermore, an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film is formed on the substrate on which the organic sealing film 62 has been formed using a mask by plasma CVD to form a second inorganic sealing film 63, thereby forming a sealing film 65.

[0074] Finally, a protective sheet (not shown) is attached to the surface of the substrate on which the sealing film 65 is formed, and then laser light is irradiated from the glass substrate side of the resin substrate 10 to peel the glass substrate from the underside of the resin substrate 10, and further a protective sheet (not shown) is attached to the underside of the resin substrate 10 from which the glass substrate has been peeled.

[0075] In this manner, the organic EL display device 100 of this embodiment can be manufactured.

[0076] As described above, according to the manufacturing method of the organic EL display device 100 of this embodiment, the first electrode formation step in the organic EL element layer formation step includes a first step of forming the first electrode 45r corresponding to the first sub-pixel Pr that displays red, a second step of forming the first electrode 45g corresponding to the second sub-pixel Pg that displays green, and a third step of forming the first electrode 45b corresponding to the third sub-pixel Pb that displays blue. Here, in the first step, the fourth transparent conductive film 33, the first metal film 34, and the first transparent conductive film 35 are formed in this order by sputtering through the first film-forming mask Ma to form the first electrode 45r. This eliminates the need for photolithography and etching, and allows the first electrode 45r to be formed by a simple process. In the second step, the fifth transparent conductive film 36, the second metal film 37, and the second transparent conductive film 38 are sequentially deposited by sputtering through the second deposition mask Mb to form the first electrode 45g, eliminating the need for photolithography and etching, and allowing the first electrode 45g to be formed by a simple process. Furthermore, in the third step, the sixth transparent conductive film 39, the third metal film 40, and the third transparent conductive film 41 are sequentially deposited by sputtering through the third deposition mask Mc to form the first electrode 45b, eliminating the need for photolithography and etching, and allowing the first electrode 45b to be formed by a simple process. Furthermore, since photolithography and etching are not required in the first, second, and third steps, there is no need to consider the generation of residues due to etching, and short circuits between the first electrodes 45r, 45g, and 45b and the second electrode 48 can be suppressed. Furthermore, in the first, second, and third steps, the film thicknesses of the first transparent conductive film 35 to the sixth transparent conductive film 39 and the first metal film 34 to the third metal film 40 can be appropriately set by changing the film formation conditions, etc., so that the optical path length can be set for each of the first sub-pixel Pr, the second sub-pixel Pg, and the third sub-pixel Pb, and a cavity structure that improves light extraction efficiency by the optical resonance effect can be formed. Therefore, a cavity structure can be formed by a simple process while suppressing the occurrence of short circuits between the first electrode 45 and the second electrode 48.

[0077] Other Embodiments In the first embodiment, the organic EL layer has a five-layer laminated structure including a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. However, the organic EL layer may have a three-layer laminated structure including, for example, a hole injection layer / hole transport layer, a light-emitting layer, and an electron transport layer / electron injection layer.

[0078] In addition, in the first embodiment described above, an organic EL display device in which the first electrode is an anode and the second electrode is a cathode is exemplified. However, the present invention can also be applied to an organic EL display device in which the layered structure of the organic EL layer is reversed, and the first electrode is a cathode and the second electrode is an anode.

[0079] Furthermore, in the first embodiment described above, an organic EL display device is exemplified in which the electrode of the TFT connected to the first electrode is used as the drain electrode, but the present invention can also be applied to an organic EL display device in which the electrode of the TFT connected to the first electrode is called the source electrode.

[0080] Furthermore, in the above-described first embodiment, an organic EL display device has been described as an example of the display device. However, the present invention can be applied to a display device including a plurality of light-emitting elements driven by current, and can be applied to, for example, a display device including QLEDs (Quantum-dot light emitting diodes), which are light-emitting elements using a quantum dot-containing layer.

[0081] As described above, the present invention is useful for flexible display devices.

[0082] D Display area Ma First film deposition mask Mb Second film deposition mask Mc Third film deposition mask P Sub-pixel Pr First sub-pixel Pg Second sub-pixel Pb Third sub-pixel 10 Resin substrate (base substrate) 30 TFT layer (thin film transistor layer) 31, 31r, 31g, 31b Third electrode 33 Fourth transparent conductive film 34 First metal film 35 First transparent conductive film 36 Fifth transparent conductive film 37 Second metal film 38 Second transparent conductive film 39 Sixth transparent conductive film 40 Third metal film 41 Third transparent conductive film 45, 45r, 45g, 45b First electrode 47 Organic EL layer (organic electroluminescence layer, light-emitting function layer) 48 Second electrode 60 Organic EL element layer (light-emitting element layer) 65 Sealing film 100 Organic EL display device

Claims

1. A method for manufacturing a display device comprising: a base substrate; a thin film transistor layer provided on the base substrate; and a light emitting element layer provided on the thin film transistor layer, in which a plurality of first electrodes, a plurality of light emitting functional layers, and a common second electrode are laminated in this order corresponding to a plurality of subpixels constituting a display area, wherein the plurality of subpixels have first subpixels, second subpixels, and third subpixels that display different colors from one another, wherein the step of forming the plurality of first electrodes comprises: a first step of forming the first electrodes corresponding to the first subpixels by sequentially depositing a first metal film and a first transparent conductive film through a first deposition mask; a second step of forming the first electrodes corresponding to the second subpixels by sequentially depositing a second metal film and a second transparent conductive film through a second deposition mask; and a third step of forming the first electrodes corresponding to the third subpixels by sequentially depositing a third metal film and a third transparent conductive film through a third deposition mask.

2. A method for manufacturing a display device according to claim 1, characterized in that in the first step, the second step and the third step, the films are formed by a sputtering method.

3. A method for manufacturing a display device according to claim 1 or 2, characterized in that in the first step, a fourth transparent conductive film, the first metal film and the first transparent conductive film are formed in that order; in the second step, a fifth transparent conductive film, the second metal film and the second transparent conductive film are formed in that order; and in the third step, a sixth transparent conductive film, the third metal film and the third transparent conductive film are formed in that order.

4. A method for manufacturing a display device according to claim 3, wherein the first transparent conductive film, the second transparent conductive film, the third transparent conductive film, the fourth transparent conductive film, the fifth transparent conductive film and the sixth transparent conductive film are indium tin oxide films or indium zinc oxide films, and the first metal film, the second metal film and the third metal film are silver films or silver alloy films.

5. A method for manufacturing a display device according to any one of claims 1 to 4, wherein the first metal film, the second metal film and the third metal film have the same thickness, and the first transparent conductive film, the second transparent conductive film and the third transparent conductive film have different thicknesses.

6. A method for manufacturing a display device according to claim 3 or 4, wherein the fourth transparent conductive film, the fifth transparent conductive film and the sixth transparent conductive film have the same thickness.

7. A method for manufacturing a display device according to any one of claims 1 to 6, wherein the light emitting element layer comprises a plurality of third electrodes provided on the thin film transistor layer side of the plurality of first electrodes in correspondence with the plurality of sub-pixels and electrically connected to the plurality of first electrodes, respectively.

8. A method for manufacturing a display device according to any one of claims 1 to 7, characterized in that a sealing film is provided on the light emitting element layer.

9. A method for manufacturing a display device according to any one of claims 1 to 8, wherein at least one of the plurality of light-emitting functional layers is an organic electroluminescence layer.

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