JP4506788B2 - EL panel manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an EL panel including a substrate and an EL element provided on the substrate.

  The organic EL element has a laminated structure in which an anode electrode, an organic EL layer made of an organic material, and a cathode electrode are laminated in this order. When a forward bias voltage is applied between the anode electrode and the cathode electrode, Emits light. An organic EL display panel that displays images by arranging such organic EL elements as pixels in a matrix on a substrate and emitting each organic EL element with a predetermined gradation luminance is realized.

  In an organic EL display panel having an active matrix structure, one of the anode electrode and the cathode electrode can be a common electrode common to all pixels, but at least the other electrode and the organic EL layer are patterned for each pixel. There is a need to. A conventional semiconductor element manufacturing technique can be applied to the method of patterning the anode electrode and the cathode electrode for each pixel. In other words, the anode electrode and the cathode electrode can be appropriately formed by performing a film forming process such as a vacuum deposition method, a PVD method such as a sputtering method or a CVD method, a masking step such as a photolithography method, and a thin film shape processing step such as an etching method. Can be patterned for each pixel.

  The method for forming the organic EL layer can be broadly classified into a dry vapor deposition method and a wet coating method according to conditions such as materials. In the case of using the dry evaporation method, after forming the organic EL layer on the entire surface by the dry evaporation method, a shadow mask is performed, and then the portion without the mask is removed by etching, thereby patterning the organic EL layer for each pixel. it can. On the other hand, when the wet coating method is used, the organic EL layer can be patterned for each pixel by applying an inkjet technique. That is, the organic EL layer can be patterned for each pixel by ejecting a droplet of an EL solution obtained by dissolving a material that becomes the organic EL layer with a solvent for each pixel. In the wet coating method using the ink jet technology, the film forming process and the patterning process for each pixel can be performed almost simultaneously, so the ink jet method is becoming a mainstream technology.

  By the way, in order to provide an organic EL display panel that performs high-resolution image display, the organic EL layer must be formed in a fine pattern. In the inkjet method, since the particle size of the droplets of the EL solution is very small, it is possible to form the organic EL layer with a fine pattern, but since the droplets solidify in the landed shape, the desired shape is obtained. Since it is difficult to form a film and it spreads and diffuses until solidifying, there is a possibility that it may be mixed with the EL solution of the organic EL layer of the adjacent pixel due to a slight misalignment of the ink jet head or a landing position deviation. . Therefore, a technique for preventing the EL solution of adjacent pixels from being mixed is proposed by finely patterning a mesh-like partition wall on the substrate in advance and then ejecting a droplet to a region surrounded by the partition wall. Yes. (For example, refer to Patent Document 1.)

  FIG. 11 shows a conventional organic EL display panel 301 having a partition wall 308. In this organic EL display panel 301, a partition wall 308 having a mesh shape in plan view is formed on the substrate 312, and one organic EL element 302 is provided in one region surrounded by the partition wall 308. A plurality of EL elements 302 are arranged in a matrix. In order to improve the adhesion of the partition 308, a network-like base layer 309 made of silicon oxide is formed between the partition 308 and the substrate 312.

  As a manufacturing method of the organic EL display panel 301, first, a plurality of anode electrodes 315 are patterned on a substrate 312 in a matrix shape, and then a base layer 309 is patterned on the substrate 312 between the anode electrodes 315 in a mesh shape. To do. Next, the partition 308 is patterned on the base layer 309.

  Next, this substrate 312 is set in an oxygen plasma cleaning device, and the organic electrode attached on the anode electrode 315 is ashed by the oxygen plasma cleaning device, thereby cleaning the anode electrode 315. The reason for cleaning the anode electrode 315 is that when the organic EL layer 316 is formed by an ink jet method, the droplets of the EL solution are easily wetted on the anode electrode 315.

  Next, this substrate 312 is set in a fluoride plasma irradiation apparatus, and the fluoride plasma irradiation is performed on the partition wall 308 with the fluoride plasma irradiation apparatus, thereby forming a highly liquid-repellent fluoride layer on the surface layer of the partition wall 308. The reason why the fluoride layer having high liquid repellency is formed on the surface layer of the partition wall 308 is to prevent the EL solution from spreading on the partition wall 308 even when a large amount of EL solution that is higher than the top of the partition wall 308 is ejected. This is because the EL solution is fixed only on the anode electrode 315 and the EL solution of adjacent pixels on the partition wall 308 is prevented from being mixed.

Next, the substrate 312 is set in an ink jet film forming apparatus, and an EL solution is ejected onto each anode electrode 315 by the ink jet film forming apparatus, followed by drying, and an organic EL layer 316 is patterned on each anode electrode 315. To do. Next, a cathode electrode 317 is formed on the organic EL layer 312.
JP 2000-323276 A

  In the above manufacturing method, since the partition 308 is patterned after the base layer 309 is patterned, the width of the base layer 309 is reduced in plan view so that the partition 308 is reliably formed on the base layer 309. It is necessary to make it wider than the width of the partition wall 308. Thus, since the width of the base layer 309 is wider than the width of the partition wall 308 and the base layer 309 is formed on the peripheral edge of the anode electrode 315, the light emitting portion is narrow and the so-called aperture ratio is low. On the other hand, even when the aperture ratio is increased by narrowing the width of the base layer 309, the partition wall 308 protrudes over the anode electrode 315 in the formation of the partition wall 308, so that the adhesion of the partition wall 308 is lowered. Therefore, the partition 308 may be peeled off from the portion overlapping the anode electrode 315.

  On the other hand, if oxygen plasma cleaning is not performed, the EL solution does not spread on the anode electrode 315, and there is a possibility that a portion where the organic EL layer 316 is not formed on the anode electrode 315 may be generated. In addition, if fluoride plasma irradiation is not performed, the EL solution may ooze on the partition 308, and the EL solution of adjacent pixels may be mixed on the partition 308. However, since the oxygen plasma cleaning and fluoride plasma irradiation are performed, the manufacturing process becomes complicated.

  As described above, the conventional manufacturing method has a limit in achieving both the provision of a high-quality organic EL display panel and the simplicity of the manufacturing process. Accordingly, an object of the present invention is to provide both a high-quality EL display panel and a simple manufacturing process.

In order to solve the above-described problems, the manufacturing method according to the first aspect of the present invention is, for example, as shown in FIGS. A base film forming step (for example, FIG. 5) for forming a base film (for example, a silicon oxide base film 9 ′) on one surface of the substrate so as to cover the first electrode (for example, the anode electrode 15) formed on the substrate. 4), a resist film forming step (for example, illustrated in FIG. 5) for forming a resist film (for example, resist film 8 ′) on one surface of the base film, and partially removing the resist film A shape processing step (for example, shown in FIG. 6) for processing the resist film so that the first electrode is disposed in the surrounding region surrounded by the remaining resist film (for example, the partition wall 8); The resist film used as a mask And Te C ₄ F ₈ or CF ₄ etching process for forming a liquid repellent layer on the surface layer of the resist film at the same time etching the underlying film with a gas (e.g. shown in FIG. 7), EL layer between the resist film And an EL layer forming step (for example, shown in FIG. 8).

  According to a second aspect of the present invention, in the manufacturing method according to the first aspect, in the shape processing step, the resist film is shape-processed so that the remaining resist film overlaps an outer edge portion of the first electrode. And

  A third aspect of the present invention is the manufacturing method according to the first or second aspect, wherein the first electrode formed on one surface of the substrate is plural, and the plurality of first electrodes are formed in the base film forming step. The resist film is coated with the base film, and the resist film is shaped so that a plurality of the surrounding areas are formed in the shaping process and at least one of the first electrodes is arranged in one surrounding area. It is characterized by.

  According to a fourth aspect of the present invention, in the manufacturing method according to the third aspect, the EL layer (for example, the organic EL layer 16) is formed by using an EL solution in which an EL material is dissolved as a droplet (for example, the droplet 116). It is formed by ejecting toward the Go area.

  In the invention according to any one of the first to fourth aspects, the resist film remaining after the resist film is shaped corresponds to the conventional partition wall 308. Here, since the underlying film is etched using the remaining resist film as a mask, the shape of the remaining underlying film matches the shape of the remaining resist film. The remaining base film corresponds to the conventional base layer 309, and the remaining base film matches the remaining resist film (that is, the partition wall), so that the light emission range of the EL element can be maximized. Further, since the remaining resist film matches the remaining base film, the remaining resist film does not protrude from the base film to the first electrode or the substrate, so that the remaining resist film is difficult to peel off. Therefore, a high quality EL panel can be provided.

  In addition, since the base film is processed using the remaining resist film as a mask, the steps are different from those in the case where the partition wall 308 is formed on the base layer 309 after patterning the base layer 309 as in the prior art. Omitted to simplify the EL panel manufacturing method. As described above, in the invention according to any one of claims 1 to 4, it is possible to achieve both the provision of a high-quality EL panel and the simplicity of the manufacturing process.

Further, since the underlying film is etched with a gas containing C ₄ F ₈ or CF ₄ using the remaining resist film as a mask, a layer of a compound containing fluorine is formed on the surface layer of the remaining resist film. Since a fluorine-containing compound layer generally has high liquid repellency, even if the remaining resist film is not irradiated with fluoride plasma, the EL solution does not spread on the remaining resist film. Therefore, when an EL layer is formed with an EL solution as in the fourth aspect of the invention, the EL solution of adjacent pixels is not mixed on the remaining resist film. In addition, since the EL solution does not spread on the remaining resist film even if fluoride plasma irradiation is omitted, the EL panel manufacturing method is simplified compared to the conventional manufacturing method.

  As described above, according to the invention of any one of claims 1 to 4, since the shape of the remaining silicon oxide film matches the shape of the remaining resist film, the remaining silicon oxide and the remaining resist film are surrounded. In the enclosed region, the light emission range of the EL element composed of the first electrode, the EL layer, and the second electrode can be maximized. Therefore, a high quality EL panel can be provided. In addition, since the silicon oxide film is shaped using the remaining resist film as a mask, the remaining resist film becomes a partition surrounding the EL element including the first electrode, the EL layer, and the second electrode. Therefore, the process is omitted, and the EL panel manufacturing method is simplified.

  Further, since the compound layer containing fluorine is formed on the surface layer of the remaining resist film, the remaining resist film may not be irradiated with fluoride plasma. Therefore, the EL panel manufacturing method can be simplified compared to the conventional manufacturing method.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In the following description, “when viewed in plan” means “when viewed in a direction perpendicular to the light emitting surface”.

  FIG. 1 shows a cross-sectional view of the organic EL display panel 1. In plan view, the organic EL display panel 1 has a plurality of red, green, and blue pixels arranged in a matrix, and one pixel emits light from one organic EL element 2 (details will be described later). And a non-light emitting portion 4 that does not emit light around the light emitting portion 3.

  The organic EL display panel 1 performs color display by an active matrix driving method. That is, the organic EL display panel 1 includes one organic EL element 2 and one pixel switching circuit (including the thin film transistor 5) for driving the organic EL element 2 for each pixel. The pixel switching circuit turns on / off the current flowing through the organic EL element 2 in accordance with the signal output from the peripheral driver circuit, or maintains the current value during the light emission period of the organic EL element 2, thereby emitting light from the organic EL element 2. Is controlled to be constant. Each pixel switching circuit is composed of at least one thin film transistor (hereinafter referred to as TFT), and a capacitor or the like may be added as appropriate. An example of the TFT 5 that is directly connected to the organic EL element 2 without passing through other electric elements will be described.

  The organic EL display panel 1 includes a TFT drive substrate 6 having a pixel switching circuit (including TFT 5), a flat counter substrate 7 facing the TFT drive substrate 6, and between the TFT drive substrate 6 and the counter substrate 7. A plurality of organic EL elements 2 patterned and formed in a matrix, a planar partition wall 8 provided around the organic EL element 2, and a plan view formed between the partition wall 8 and the TFT drive substrate 6. A network-like base layer 9, a partition wall 8, a liquid repellent layer 10 on the surface of the base layer 9, a sealing resin layer 11 for sealing the organic EL element 2, and the like are provided.

  The TFT drive substrate 6 is basically composed of an insulating transparent substrate 12 that is transparent to light. The transparent substrate 12 is formed in a flat plate shape using a material such as borosilicate glass, quartz glass, or other glass. The TFT 5, the wiring 19 (for example, scanning lines, signal lines, etc.), other electric elements, etc. are formed on one surface 12 a of the transparent substrate 12, and the gate insulating film 13 and the interlayer insulating film 14 are formed on the entire surface of the transparent substrate 12. The TFT drive substrate 6 is configured by forming a film.

  The TFT 5 is a MOS field effect transistor composed of a gate electrode, a drain electrode, a source electrode, a semiconductor layer, an impurity semiconductor layer, and the like. The semiconductor layer may be amorphous silicon or polysilicon, An inverted staggered structure or a coplanar structure may be used. Further, the TFT 5 is connected to the wiring 19, and a current flows from the peripheral driver circuit to each TFT 5 or a voltage is applied. The gate insulating film 13 is interposed between the semiconductor layer, the impurity semiconductor layer, the source electrode, the drain electrode, and the gate electrode of the TFT 5 and covers the wiring 19 such as a scanning line. The gate insulating film 13 is transparent to visible light and has an insulating property. The interlayer insulating film 14 covers all the TFTs 5 and constitutes the surface 6 a of the TFT drive substrate 6. The interlayer insulating film 14 also covers wiring such as signal lines. The interlayer insulating film 14 has a light-transmitting property with respect to visible light and an insulating property.

A plurality of organic EL elements 2 are arranged in a matrix on the interlayer insulating film 14. Each organic EL element 2 includes an anode electrode (first electrode) 15, an organic EL layer 16, and a cathode electrode (second electrode) 17, and the anode electrode 15 and organic layers are sequentially formed from the interlayer insulating film 14 side. It has a laminated structure in which the EL layer 16 and the cathode electrode 17 are laminated.
Here, the cathode electrode 17 is an electrode common to all the organic EL elements 2, and is formed on one surface. On the other hand, the anode electrode 15 and the organic EL layer 16 are provided for each pixel, and are arranged in a plurality of matrices in plan view.

The anode electrode 15 has conductivity and translucency for visible light. Furthermore, it is preferable that the anode electrode 15 has a relatively high work function and efficiently injects holes into the organic EL layer 12. The anode electrode 15 is preferably indium-tin-oxide (ITO). For example, zinc-doped indium oxide (IZO), indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ). Alternatively, the main component may be zinc oxide (ZnO). Note that a contact hole 18 is provided in the interlayer insulating film 14 for each pixel, and the drain electrode or the cathode electrode of the TFT 5 is electrically connected to the anode electrode 15 through the contact hole 18.

  The organic EL layer 16 is formed on the anode electrode 15. The organic EL layer 16 may have, for example, a three-layer structure including a hole transport layer, a narrow light emitting layer, and an electron transport layer in order from the anode electrode 15, or a hole transport layer and a narrow sense in order from the anode electrode 15. The light emitting layer may have a two-layer structure or a single-layer structure composed of a narrowly defined light emitting layer, or a laminated structure in which an electron or hole injection layer is interposed between appropriate layers in these layer structures. Or other layer structures.

  The organic EL layer 16 has a function of injecting holes and electrons, a function of transporting holes and electrons, and a function of generating excitons by recombination of holes and electrons to emit red, green, or blue light. Is a light emitting layer in a broad sense. That is, when the pixel is red, the organic EL layer 16 of the pixel emits red light, and when the pixel is green, the organic EL layer 16 of the pixel emits green light and the pixel is blue. The organic EL layer 16 of the pixel emits blue light.

  The organic EL layer 16 is desirably an electronically neutral organic compound, whereby holes and electrons are injected and transported in the organic EL layer 16 in a balanced manner. In addition, an electron transporting substance may be appropriately mixed in the narrowly defined light emitting layer, a hole transporting substance may be appropriately mixed in the narrowly defined light emitting layer, or the electron transporting substance and the hole may be mixed. A transporting substance may be appropriately mixed in the light-emitting layer in the narrow sense. The organic EL layer 16 contains a light emitting material (fluorescent material), but the light emitting material is a polymer material. The organic EL layer 16 is formed by a droplet ejection method (so-called ink jet method) by a film forming apparatus 50 described later.

  The cathode electrode 17 is formed of a material having a low work function. Specifically, the cathode electrode 17 is formed of magnesium, calcium, lithium, barium, an alloy or a mixture containing at least one of them, and aluminum is formed thereon. The laminated structure is covered with a high work function and low resistance material such as chromium. The cathode electrode 17 desirably has a light shielding property with respect to visible light, and desirably has a high reflectivity with respect to visible light emitted from the organic EL layer 16. That is, the cathode electrode 17 acts as a mirror surface that reflects visible light.

The base layer 9 and the partition wall 8 are provided in a mesh shape in plan view so as to partition the plurality of anode electrodes 15 and the organic EL layer 16 arranged in a matrix. The underlayer 9 is made of silicon oxide (SiO ₂ ) and has transparency to visible light and insulation.

  The partition wall 8 is formed on the base layer 9 and matches the shape of the base layer 9 in plan view. Accordingly, the partition wall 8 does not protrude from the base layer 9 and the base layer 9 does not protrude from the partition wall 8 in plan view. The partition wall 8 is made of a photosensitive resin such as a polyimide resin. Since the base layer 9 is interposed between the partition wall 8 and the TFT drive substrate 6, the adhesion of the partition wall 8 to the TFT drive substrate 6 is enhanced. The liquid repellent layer 10 is formed on the surface layer of the partition wall 8 and the base layer 9. The liquid repellent layer 10 is a compound of fluorine and carbon, and the material of the organic EL layer 16 (organic EL material) is at a concentration of several percent. It has the property of repelling an EL solution dissolved in a solvent. Since the cathode electrode 17 is an electrode common to all the organic EL elements 2, it is also formed on the upper surface of the partition wall 8 and the side surface of the partition wall 8.

  The sealing resin layer 11 is formed so as to cover the entire plurality of organic EL elements 2 configured as described above. This sealing resin layer 11 is formed of, for example, an epoxy resin. The counter substrate 7 is bonded onto the organic EL element 2 by the sealing resin layer 11 and is formed of a material such as borosilicate glass, quartz glass, or other glass.

Next, the film forming apparatus 50 for forming the organic EL layer 16 by the droplet ejection method will be described.
FIG. 2 is a schematic side view showing the film forming apparatus 50.
In the film forming apparatus 50, the material of the organic EL layer 16 (organic EL material such as a light emitting substance, a hole transporting substance, and an electron transporting substance) is mixed with an organic solvent (for example, toluene or xylene) or a water-soluble solvent. The organic EL layer 16 is formed by ejecting the dissolved EL solution as droplets onto the TFT drive substrate 6. Here, when forming the organic EL layer 16, the TFT drive substrate 6 in which the base layer 9, the partition wall 8, and the anode electrode 15 are formed on the surface 6a is used.

  The film forming apparatus 50 includes a work table 51 having a flat and horizontal upper surface, and a moving apparatus that moves the work table 51 in both the forward and reverse directions in the sub-scanning direction Y (parallel to the work table 51). 52, a guide part 53 extending in a main scanning direction X (parallel to the work table 51) substantially perpendicular to the sub-scanning direction Y, and a guide part 53 guided by the guide part 53 along the guide part 53. A head portion 54 that moves in the forward and reverse directions of the scanning direction X, a plurality of nozzles 55R, 55G, and 55B that eject the EL solution as droplets, an oxygen plasma irradiation head 56 and a fluoride plasma irradiation head that perform plasma irradiation 57, a box 66 having an internal space 66a, and the like.

The TFT drive substrate 6 is placed on the work table 51.
The moving device 52 conveys the TFT drive substrate 6 in the sub-scanning direction Y together with the work table 51 in accordance with the operation of the head unit 54, and specifically conveys the TFT drive substrate 6 intermittently. is there.

  The head portion 54 reciprocates in the main scanning direction X along the guide portion 53 on the work table 51 in accordance with intermittent conveyance of the TFT drive substrate 6. When it is stopped, it moves at least once in the main scanning direction X.

  The head portion 54 is provided with a plurality of nozzles 55R, 55G, and 55B. The nozzles 55R, 55G, and 55B are arranged in a line in the main scanning direction X at equal intervals.

  Each nozzle 55R, 55G, 55B is filled with an EL solution containing organic EL materials having different emission colors, and each nozzle 55R, 55G, 55B is provided with ejection means, and the nozzle 55R. , 55G, 55B are provided with jet outlets 55Ra, 55Ga, 55Ba, respectively. The nozzles 55R, 55G, and 55B eject the EL solution toward the TFT drive substrate 6 from the respective ejection ports 55Ra, 55Ga, and 55Ba by the operation of the ejection means. Examples of the ejection means include a thermal jet type, a piezo type, and an electrostatic type.

  The thermal jet type ejecting means ejects droplets of the EL solution by changing the pressure in the nozzles 55R, 55G, and 55B by generating bubbles in the EL solution in the nozzles 55R, 55G, and 55B with a heating element. To do.

  Piezo-type ejection means ejects droplets of an EL solution by changing the pressure in the nozzles 55R, 55G, and 55B by changing the volume of the piezo elements in contact with the solution in the nozzles 55R, 55G, and 55B. To do.

  The electrostatic ejection means applies a voltage to a capacitor in contact with the solution in the nozzles 55R, 55G, and 55B to change the attractive force or repulsive force of the electrodes of the capacitor, thereby changing the pressure of the solution in the nozzles 55R, 55G, and 55B. The liquid droplets of the EL solution are ejected by changing.

  The EL solution of the organic EL layer 16 that emits red light is ejected from the ejection port 55Ra, the EL solution that emits green light is ejected from the ejection port 55Ga, and the EL solution that emits blue light is ejected from the ejection port 55Ba. The

  Further, the head unit 54 is provided with an oxygen plasma irradiation head 56 and a fluoride plasma irradiation head 57. The oxygen plasma irradiation head 56 performs oxygen plasma irradiation toward the TFT drive substrate 6. The fluoride plasma irradiation head 57 performs plasma irradiation of fluoride toward the TFT drive substrate 6.

  In the oxygen plasma irradiation, oxygen gas is supplied from the oxygen gas supply source 58 to the gas mixer 60, argon gas or helium gas is supplied from the inert gas supply source 59 to the gas mixer 60, and oxygen gas and argon gas are mixed. A mixed gas or a mixed gas of oxygen gas and helium gas is supplied from the gas mixer 60 to the oxygen plasma irradiation head 56. Here, when a high frequency voltage is applied to the electrode of the oxygen plasma irradiation head 56 by the high frequency power supply 61, oxygen plasma (ionized oxygen gas (for example, oxygen radical, oxygen radical, oxygen gas) from the oxygen plasma irradiation head 56 toward the TFT drive substrate 6 is obtained. Ions))). The plasma irradiated from the oxygen plasma irradiation head 56 is a plasma at atmospheric pressure, but may be a reduced-pressure plasma whose atmospheric pressure is lower than the atmospheric pressure.

In the fluoride plasma irradiation, F ₂ gas or CF ₄ gas (hereinafter, F ₂ gas and CF ₄ gas are collectively referred to as fluoride gas) is supplied from the fluoride gas supply source 62 to the gas mixer 64. Argon gas or helium gas is supplied from the inert gas supply source 63 to the gas mixer 64, and a mixed gas of fluoride gas and argon gas, or a mixed gas of fluoride gas and helium gas is supplied from the gas mixer 64 to fluoride plasma. It is supplied to the irradiation head 57. Here, when a high frequency voltage is applied to the electrode of the fluoride plasma irradiation head 57 by the high frequency power source 65, fluoride plasma (ionized fluoride gas (for example, ionized fluoride gas (for example, for example)) is directed from the fluoride plasma irradiation head 57 toward the TFT drive substrate 6. Fluoride radicals, fluoride ions, etc.) are irradiated. The plasma irradiated from the fluoride plasma irradiation head 57 is an atmospheric pressure plasma, but may be a reduced pressure plasma having an atmospheric pressure lower than the atmospheric pressure. Note that O ₂ gas may be supplied to the gas mixer 64.

  The oxygen plasma irradiation head 56 and the fluoride plasma irradiation head 57 are arranged in a line in the main scanning direction X together with the nozzles 55R, 55G, and 55B. That is, the oxygen plasma irradiation head 56, the fluoride plasma irradiation head 57, and the nozzles 55R, 55G, and 55B are arranged in a straight line, and the oxygen plasma irradiation head 56, the fluoride plasma irradiation head 57, and the nozzles 55R, 55G, and 55B are arranged. The connecting straight line is parallel to the main scanning direction X.

  The oxygen plasma irradiation head 56 is disposed in front of the forward direction of the main scanning direction X, and a fluoride plasma irradiation head 57 is disposed on the opposite side of the oxygen plasma irradiation head 56, so that fluoride plasma irradiation is performed. Nozzles 55R, 55G, and 55B are arranged on the opposite side of the head 57. Therefore, when the head unit 54 moves in the forward direction of the main scanning direction X, the oxygen plasma irradiation head 56, the fluoride plasma irradiation head 57, the nozzles 55R, 55G, Pass in the order of 55B. The arrangement order of the nozzles 55R, 55G, and 55B may be any arrangement order.

  The work table 51, the nozzles 55R, 55G, and 55B, the oxygen plasma irradiation head 56, and the fluoride plasma irradiation head 57 are disposed in a box 66. Accordingly, the TFT drive substrate 6 is moved in the sub-scanning direction Y, the EL solution droplets are ejected from the nozzles 55R, 55G, and 55B, and the EL solution droplets land on the TFT drive substrate 6. Irradiation of oxygen plasma to the TFT drive substrate 6 and irradiation of fluoride plasma to the TFT drive substrate are performed in the internal space 66 a of the box 66.

  Note that the moving device 52, the head portion 54, the nozzles 55R, 55G, and 55B, the oxygen plasma irradiation head 56, the fluoride plasma irradiation head 57, the high frequency power supply 61, and the high frequency power supply 65 are controlled by a control device (not shown) to have a predetermined timing. Operate with or stop.

A method for manufacturing the organic EL display panel 1 will be described.
First, the TFT drive substrate 6 is manufactured. That is, a pixel switching circuit (including the TFT 5) is provided for each pixel by appropriately performing a film forming process such as a PVD method or a CVD method, a masking process such as a photolithography method, and a thin film shape processing process such as an etching method. Then, the wiring 19 is patterned on the surface 12a, and the interlayer insulating film 14 is formed on one surface.

  Next, after forming a contact hole in the interlayer insulating film 14, a film forming process by a PVD method or a CVD method, a mask process by a photolithography method or the like, and a thin film shape processing process by an etching method or the like are appropriately performed. A plurality of anode electrodes 15 are formed in a matrix on 14, and the anode electrodes 15 are connected to the TFTs 5 through the contact holes 18 (FIG. 3). FIG. 3B is a plan view of the TFT drive substrate 6 immediately after this step, and FIG. 3A is a cross-sectional view taken along the broken line AA in FIG.

  Next, a silicon oxide base film 9 ′ is formed on one surface of the interlayer insulating film 14 on which the plurality of anode electrodes 15 are formed by performing a film forming process such as a PVD method or a CVD method (FIG. 4). Here, the silicon oxide base film 9 ′ is formed so as to cover all the anode electrodes 15 with the silicon oxide base film 9 ′. 4B is a plan view of the TFT drive substrate 6 immediately after this process, and FIG. 4A is a cross-sectional view taken along the broken line BB in FIG. 4B.

  Next, a resist film 8 'of a photosensitive resin is formed on one surface of the silicon oxide base film 9' by a spin coat method or a dip method (FIG. 5). Since the silicon oxide base film 9 ′ has high adhesion to the resist film 8 ′, the silicon oxide base film 9 ′ is not formed on the glass surface of the transparent substrate 12 or the surface of the anode electrode 15 of the TFT drive substrate 6. The resist film 8 ′ is less likely to be peeled off than when the resist film 8 ′ is formed directly. 5B is a plan view of the TFT drive substrate 6 immediately after this step, and FIG. 5A is a cross-sectional view taken along the broken line CC in FIG. 5B.

  Next, in order to process the shape of the resist film 8 ', the resist film 8' is selectively exposed. Here, when the resist film 8 'is a negative type, a portion to be the partition wall 8 is exposed, and when the resist film 8' is a positive type, the portion other than the portion to be the partition wall 8 is exposed. Next, a developing solution is sprayed on the resist film 8 ′, and the resist film 8 ′ other than the portion that becomes the partition wall 8 is removed with the developing solution, so that the resist film 8 ′ is processed. The remaining portion of the resist film 8 'becomes the partition wall 8 (FIG. 6). Here, as shown in FIG. 6B, the resist film 8 ′ is shaped so that a part of the partition wall 8 overlaps the outer edge portion of each anode electrode 15 in plan view. The resist film 8 ′ is shaped to form the partition wall 8. A plurality of surrounding regions surrounded by the partition wall 8 are formed. At this time, one anode electrode 15 is arranged in each surrounding region in plan view. Is done. 6B is a plan view of the TFT drive substrate 6 immediately after this step, and FIG. 6A is a cross-sectional view taken along the broken line DD in FIG. 6B.

Next, dry etching (plasma etching) is performed on the silicon oxide base film 9 ′ with C ₄ F ₈ gas using the partition wall 8 as a mask. As a result, the portion of the silicon oxide base film 9 ′ that does not overlap the partition wall 8 in plan view is removed, and the portion that overlaps the partition wall 8 remains to form the base layer 9 (FIG. 7). Since the partition wall 8 is used as a mask, as shown in FIG. 7B, the shape of the remaining portion of the silicon oxide base film 9 ′ (that is, the base layer 9) matches the partition wall 8 in plan view. The base layer 9 does not protrude from the partition wall 8, and the partition wall 8 does not protrude from the base layer 9. By removing the silicon oxide base film 9 ′ in the surrounding region surrounded by the partition wall 8, the anode electrode 15 is exposed in the surrounding region.

Further, when C ₄ F ₈ is turned into plasma in dry etching, radical species of CF and CF ₂ are generated, but since the radical species react with silicon oxide, the silicon oxide base film 9 ′ is removed. On the other hand, since the radical species do not react with the photosensitive resin (polyimide resin), the radical species are polymerized on the surface layer of the partition wall 8 to form a fluorine and carbon compound, and the liquid repellent layer 10 is formed on the surface layer of the partition wall 8. It is formed. Therefore, the silicon oxide base film 9 ′ is processed by dry etching of C ₄ F ₈ gas using the partition wall 8 as a mask, and the liquid repellent layer 10 is formed on the surface layer of the partition wall 8 simultaneously. In addition, the shape of the underlayer 9 can be matched with the partition wall 8. Note that CF ₄ or a mixed gas containing at least one of them may be used instead of C ₄ F ₈ as an etching gas, and the silicon oxide base film 9 ′ can be etched and the surface of the partition wall 8 is made of a fluorine compound. Any fluorine compound gas that can form the liquid layer 10 may be used. 7B shows a plan view of the TFT drive substrate 6 immediately after this step, and FIG. 7A shows a cross-sectional view taken along the broken line EE in FIG. 7B.

  Next, the TFT drive substrate 6 on which the anode electrode 15, the partition wall 8, the base layer 9 and the liquid repellent layer 10 are formed is set in the film forming apparatus 50. That is, the TFT drive substrate 6 is placed on the work table 51 in the box 66. Next, using the film forming apparatus 50, the anode electrode 15 is irradiated with oxygen plasma to clean the anode electrode 15, and the partition wall 8 is irradiated with fluoride plasma so that the liquid repellent layer 10 is formed on the surface layer of the partition wall 8. The organic EL layer 16 is formed in the surrounding region surrounded by the partition wall 8 by ejecting a droplet of the organic solvent to the surrounding region surrounded by the partition wall 8.

Specifically, the film forming apparatus 50 operates as follows under the control of the control apparatus.
That is, the film forming apparatus 50 intermittently conveys the TFT drive substrate 6 in the sub-scanning direction Y by the moving device 52. Here, when the TFT drive substrate 6 is stopped, the head portion 54 reciprocates in the main scanning direction X at least once.

  As shown in FIG. 8, while the head portion 54 is moving in the forward direction of the main scanning direction X, first, the oxygen plasma irradiation head 56 passes immediately above the anode electrode 15 and the fluoride plasma irradiation head. 57 passes immediately above the partition wall 8. While the oxygen plasma irradiation head 56 is passing immediately above the anode electrode 15, the oxygen plasma irradiation head 56 ejects oxygen plasma toward the anode electrode 15, whereby the organic adhering to the surface of the anode electrode 15. Unnecessary substances are ashed (ashed), and the anode electrode 15 is cleaned.

  On the other hand, while the fluoride plasma irradiation head 57 is passing immediately above the partition wall 8, the fluoride plasma irradiation head 57 ejects fluoride plasma toward the partition wall 8, thereby The radical species of the fluoride plasma is polymerized to form the liquid repellent layer 10 on the surface layer of the partition wall 8. Even when the liquid repellent layer 10 is not sufficiently formed by the previous dry etching, the liquid repellent layer 10 is reliably formed on the surface layer of the partition wall 8 by the fluoride plasma irradiation.

  After the oxygen plasma irradiation head 56 passes over the anode electrode 15, the nozzles 55 </ b> R, 55 </ b> G, and 55 </ b> B pass immediately above the anode electrode 15. While the nozzles 55R, 55G, and 55B are passing over the anode electrode 15, one nozzle corresponding to the color of the nozzles 55R, 55G, and 55B is directed toward the anode electrode 15 to drop the EL solution 116. As one or more times.

  The droplets 116 landed on the anode electrode 15 spread on the anode electrode 15 to form a film and solidify, whereby the organic EL layer 16 is formed. Since the anode electrode 15 is plasma-cleaned, the anode electrode 15 has high wettability and low liquid repellency with respect to the EL solution, so that the EL solution easily spreads on the anode electrode 15. Therefore, in the surrounding area surrounded by the partition wall 8, the EL solution spreads over the entire surface of the anode electrode 15, and the organic EL layer 16 is formed with a uniform thickness on the entire surface of the anode electrode 15.

Further, even when a large amount of EL solution that is higher than the top of the partition wall 8 is ejected, since the liquid repellent layer 10 having high liquid repellency is formed on the surface layer of the partition wall 8, the EL solution is used as the partition wall 8. Does not bleed up. Therefore, the EL solutions of two adjacent pixels are not mixed on the partition wall 8. Here, when the critical surface tension of the solid (liquid repellent layer 10) is γc, the surface tension of the liquid (EL solution) is γL, and the contact angle between the solid and the liquid is θ, the relationship as shown in Expression (1) The formula holds.
COSθ = 1 + b (γ _c −γ _L ) (1) (where b is a constant)
Considering the surface tension of the desired EL solution from the material of the liquid repellent layer 10, when the liquid repellent layer 10 is made of polytetrafluoroethylene, the critical interfacial tension γ _c is about 18 × 10 ⁻³ . For this reason, if the EL solution has a surface tension γ _L of γ _L <18 × 10 ⁻³ [N / m], the liquid repellency of the polytetrafluoroethylene liquid repellent layer 10 is generated and the effect is produced. become. Considering the desired material of the liquid repellent layer 10 from the surface tension of the EL solution, the surface tension of toluene or xylene mainly used in the organic solvent in the EL solution is γ _L ≈28 × 10 ⁻³ [N / m]. There, if less than the critical surface tension gamma _c is the surface tension of the liquid repellent layer 10 because EL solution also almost the same value, because exhibits good liquid repellency, the critical surface tension γ _c ≦ 28 × repellent layer 10 10 ⁻³ [N / m] is desirable.

  As described above, after the head unit 54 reciprocates at least once in the main scanning direction X, the film forming apparatus 50 conveys the TFT drive substrate 6 in the sub-scanning direction Y by the moving device 52. When the TFT drive substrate 6 stops again, the film forming apparatus 50 performs the reciprocating movement of the head portion 54, the ejection of the EL solution, and the plasma irradiation again. Thereafter, when the film forming apparatus 50 repeats the above-described operation, the organic EL layer 16 is formed in all the surrounding regions surrounded by the partition walls 8.

  The head unit 54 may be stopped during the plasma irradiation by the oxygen plasma irradiation head 56, the plasma irradiation by the fluoride plasma irradiation head 57, and the droplet ejection by the nozzles 55R, 55G, and 55B. However, the head part 54 may be moving. In addition, the dimensions and intervals of the partition walls 8 and the dimensions and intervals of the surrounding area surrounded by the partition walls 8 are stored in advance in the control device. Based on the stored data, the control device moves the movement speed and movement of the head unit 54. The start timing and stop timing, the moving speed of the moving device 52, the movement start timing and stop timing, the ejection timing of the nozzles 55R, 55G, and 55B, the irradiation timing of the oxygen plasma irradiation head 56, and the irradiation timing of the fluoride plasma irradiation head 57 Calculation is performed to control the moving device 52, the head unit 54, the nozzles 55R, 55G, and 55B, the oxygen plasma irradiation head 56, and the fluoride plasma irradiation head 57.

  When the film formation of the organic EL layer 16 by the film formation apparatus 50 is completed, the cathode electrode 17 is formed on one surface by performing a film formation process by a PVD method or a CVD method. Next, a fluid sealing resin is applied on one surface by a dispenser device or a spray device, and the counter substrate 7 is bonded to the cathode electrode 17 with the sealing resin. When the sealing resin is solidified, it becomes the sealing resin layer 11 and the organic EL display panel 1 is completed.

  In the above embodiment, since the base layer 9 is processed by dry etching using the partition wall 8 as a mask, the base layer 9 can be matched with the partition wall 8. Therefore, in plan view, the area of the base layer 9 can be minimized, and the light emitting unit 3 can be expanded to the maximum. Therefore, in this organic EL display panel 1, the pixel has a high light emission efficiency, and a high contrast display can be performed.

  Further, since the partition wall 8 matches the base layer 9 in plan view, the partition wall 8 does not protrude on the anode electrode 15. Therefore, the partition wall 8 is difficult to peel off.

  In addition, since the partition wall 8 is used as a mask, the steps are omitted in this embodiment as compared with the case where the partition wall 308 is formed on the base layer 309 after the shape processing to the base layer 309 as in the past. Thus, the manufacturing method of the organic EL light emitting panel is simplified.

  In the above description, fluoride film irradiation is performed by the film forming apparatus 50 in order to reliably form the liquid repellent layer 10. However, the liquid repellent layer 10 is simultaneously formed by dry etching. Therefore, fluoride plasma irradiation can be omitted.

  Since the film forming apparatus 50 has an oxygen plasma irradiation function, the anode electrode 15 is cleaned without transferring the TFT drive substrate 6 from the apparatus for plasma cleaning to the apparatus for forming the organic EL layer. And the organic EL layer 16 can be formed. That is, since the nozzles 55R, 55G, and 55B and the oxygen plasma irradiation head 56 are provided in the head portion 54, a droplet of the EL solution can be ejected to the anode electrode 15 immediately after the anode electrode 15 is plasma cleaned. . Accordingly, in a state where the wettability of the anode electrode 15 is stably maintained at a high level, the droplet of the EL solution can be landed on the anode electrode 15, and the organic EL layer 16 is formed with a uniform thickness. Can do. In addition, the occurrence of so-called white spots can be suppressed. Here, the white space is a portion where the organic EL layer 16 is not formed on the anode electrode 15 in the surrounding region surrounded by the partition wall 8 and is a portion where light is not emitted in the surrounding region surrounded by the partition wall 8.

  In addition, since the fluoride plasma irradiation function is added to the film forming apparatus 50, the liquid repellent layer is transferred without transferring the TFT drive substrate 6 from the apparatus for film irradiation with the fluoride plasma to the apparatus for film formation of the organic EL layer. 10 and the organic EL layer 16 can be formed. Accordingly, the liquid droplets of the EL solution can be landed on the anode electrode 15 in a state where the liquid repellency of the surface layer of the partition wall 8 is stably maintained high without being contaminated. Therefore, the EL solutions of two adjacent pixels are not mixed on the partition wall 8.

  Further, in the film forming apparatus 50, the oxygen plasma irradiation head 56 is provided in the head portion 54, and the oxygen plasma irradiation head 56 is configured to irradiate oxygen plasma. It is not necessary to irradiate the partition wall 8 with oxygen plasma. Therefore, the partition wall 8 is not ashed by oxygen plasma. Similarly, since the fluoride plasma irradiation head 57 is provided in the head portion 54 and is configured to irradiate fluoride plasma from the fluoride plasma irradiation head 57, it is possible to partially irradiate the partition wall 8 with oxygen plasma. It is not necessary to irradiate the anode electrode 15 with oxygen plasma. Therefore, a compound containing fluorine and carbon is not formed on the surface layer of the anode electrode 15, and the wettability of the anode electrode 15 can be maintained high.

  In addition, when the film forming apparatus 50 is used, the cleaning of the anode electrode 15, the application of liquid repellency to the partition walls 8, and the film formation of the organic EL layer 16 can be performed almost simultaneously. Is simplified.

  The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention. For example, in the above embodiment, the cathode electrode 17 is a common electrode and the anode electrode 15 is an electrode patterned for each pixel. Conversely, the cathode electrode is an electrode patterned for each pixel, and the anode electrode is a common electrode. Also good. At this time, the base layer 9 and the partition wall 8 are also formed in a mesh shape on the anode electrode, but when the partition wall 8 and the base layer 9 are formed in a mesh shape, the anode electrode is formed in the surrounding region surrounded by the partition wall 8. Is exposed.

  In the above embodiment, the plurality of anode electrodes 15 are patterned on the TFT driving substrate 6 and then the base film 9 ′ is formed. However, the plurality of anode electrodes 15 are patterned on the transparent glass substrate and then the base film 9 ′. May be formed.

  In the above embodiment, the base layer 9 and the base film 9 ′ are silicon oxide, but the base layer 9 ′ and the base film 9 ′ may be silicon nitride.

  In the above embodiment, each of the nozzles 55R, 55G, and 55B of each color provided in the head unit 54 is one, but a plurality of nozzles 55R, 55G, and 55B of each color may be provided.

  In the above embodiment, when the head unit 54 moves in the forward direction of the main scanning direction X, droplets are ejected from the nozzles 55R, 55G, and 55B, but the head unit 54 moves in the reverse direction. In this case, droplets may be ejected from the nozzles 55R, 55G, and 55B. In this case, it is desirable to provide the head 54 with a fluoride plasma irradiation head and an oxygen plasma irradiation head on the opposite side of the nozzle 55B.

In the above embodiment, the head unit 54 can be moved in the main scanning direction X, but can be moved in the main scanning direction X and the sub-scanning direction Y, that is, can be moved along a plane parallel to the work table 51. It may be. In this case, the work table 51 may be fixed.
Similarly, the work table 51 may be movable in the main scanning direction X and the sub-scanning direction Y by the moving device 52. In this case, the head part 54 may be fixed.
That is, it is only necessary that the head unit 54 can be moved relative to the TFT drive substrate 6 placed on the work table 51.

  Further, as shown in FIG. 9, the organic EL layer 16 may be formed by a film forming apparatus 150 in which the head 54 is not provided with a fluoride plasma irradiation head. As shown in FIG. Alternatively, the organic EL layer 16 may be formed by a film forming apparatus 250 that is not provided with an oxygen plasma head. In addition, regarding the film forming apparatus 150 and the film forming apparatus 250, the same reference numerals are given to the same components as those of the film forming apparatus 50, and the description thereof is omitted.

FIG. 1 is a partial cross-sectional view of an organic EL display panel. FIG. 2 is a side view showing a film forming apparatus for forming an organic EL layer. FIG. 3 is a drawing showing one step in the method of manufacturing the organic EL display panel of FIG. FIG. 4 is a drawing showing one step in the method of manufacturing the organic EL display panel of FIG. FIG. 5 is a drawing showing one step of the method of manufacturing the organic EL display panel of FIG. FIG. 6 is a drawing showing one step in the method of manufacturing the organic EL display panel of FIG. FIG. 7 is a drawing showing one step of the method of manufacturing the organic EL display panel of FIG. FIG. 8 is a drawing showing one step in the method of manufacturing the organic EL display panel of FIG. FIG. 9 is a side view showing a film forming apparatus different from the film forming apparatus of FIG. FIG. 10 is a side view showing a film forming apparatus different from the film forming apparatus shown in FIG. FIG. 11 is a plan view and a cross-sectional view showing a conventional organic EL display panel.

Explanation of symbols

1 Organic EL display panel (organic EL panel)
2 Organic EL element 5 Thin film transistor 6 TFT drive substrate (substrate)
6a Surface 7 Counter substrate 8 Partition (residual resist film)
8 'resist film 9 underlayer 9' silicon oxide underlayer (underlayer)
10 Liquid repellent layer 12 Transparent substrate 15 Anode electrode (first electrode, electrode)
16 Organic EL layer 17 Cathode electrode 50, 150, 250 Film forming apparatus 54 Head (moving body)
55R, 55G, 55B nozzle (droplet ejection part)
56 Oxygen plasma irradiation head (oxygen plasma irradiation section)
57 Fluoride plasma irradiation head (fluoride plasma irradiation section)

Claims (4)

A base film forming step of forming a base film on one surface of the substrate so as to cover the first electrode formed on one surface of the substrate;
A resist film forming step of forming a resist film on one surface of the base film;
A shape processing step for processing the resist film so as to dispose the first electrode in the surrounding region surrounded by the resist film remaining by partially removing the resist film;
Etching the base film with a gas containing C ₄ F ₈ or CF ₄ using the remaining resist film as a mask and simultaneously forming a liquid repellent layer on the surface of the resist film ;
An EL layer forming step of forming an EL layer between the resist films;
The manufacturing method of the EL panel containing this.   2. The method of manufacturing an EL panel according to claim 1, wherein, in the shape processing step, the resist film is shape-processed so that the remaining resist film overlaps with an outer edge portion of the first electrode. A plurality of the first electrodes formed on one surface of the substrate;
Covering the plurality of first electrodes with the base film in the base film forming step,
2. The shape processing of the resist film according to claim 1, wherein the resist film is shape-processed so as to form a plurality of the surrounding regions and to arrange at least one of the first electrodes in one of the surrounding regions. 2. The method for producing an EL panel according to 2.   4. The method of manufacturing an EL panel according to claim 3, wherein the EL layer is formed by ejecting an EL solution in which an EL material is dissolved as droplets toward the surrounding region.

Images