JP2013073880A - Light emitting element manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element manufacturing method capable of restraining immersion of moisture and the like into a light emitting layer.SOLUTION: Plural element regions 10 including a light emitting region 20 and a wiring region 30 adjacent to the light emitting region 20 in an X-axis direction respectively, are aligned in the X-axis direction and a Y-axis direction, so as to manufacture a substrate W. A mask 40 having plural bars 42 extending in the Y-axis direction and aligned in the X-axis direction and plural openings 43 formed between the plural bars 42 is arranged on the substrate W, so that the bars 42 cover the wiring region 30 and the light emitting region 20 is exposed from the openings 43. Inorganic films 8 and organic films 9 are alternately formed on the substrate W. The substrate W is separated for each element region 10. Thus manufactured light emitting element 1 has a protective film P including the inorganic films 8 and the organic films 9, so as to restrain immersion of moisture and the like into the light emitting layer 5 by the protective film P.

Description

  The present invention relates to a method for manufacturing a light emitting element such as an organic EL element.

  In recent years, organic EL displays using organic EL (Electro Luminescence) elements have been developed, and have already been put into practical use in some fields. The organic EL element mainly has a structure in which a light emitting layer, an electrode, and the like are stacked on a substrate. The organic compound forming the light emitting layer generally has a property that it is very easily deteriorated by moisture or oxygen. For this reason, a method of forming a protective film that suppresses intrusion of moisture or the like into the light emitting layer using a mask having a plurality of rectangular openings formed so as to correspond to individual element regions is known. .

  However, since the element formation region of the mask is determined by the opening of the mask, the element cannot be efficiently formed from a single substrate. Furthermore, since the opening is likely to be deformed due to thermal deformation or the like under high temperature conditions during film formation, it becomes difficult to form a desired protective film, and the entire mask needs to be replaced frequently.

  Therefore, Patent Document 1 discloses a mask device having a tape-like shadow mask that is fixed to a frame body at one end and extends only in one direction therefrom. This mask apparatus has a wide opening area because an opening is formed between the tape-shaped shadow masks. Therefore, an element can be efficiently formed from a single substrate and is not easily affected by distortion due to thermal deformation or the like. Furthermore, by applying tension to the other end different from the one end fixed to the frame of the shadow mask, deformation of the opening due to thermal expansion or the like can be suppressed, and the surface of the substrate can be brought into close contact without loosening. . Thus, uniform film formation is possible.

JP 2010-168654 A

  However, Patent Document 1 does not describe a specific structure of a protective film for protecting the light emitting layer from moisture or the like and a method for forming the protective film.

  In view of the circumstances as described above, an object of the present invention is to provide a method for manufacturing a light-emitting element that can suppress intrusion of moisture or the like into a light-emitting layer using a mask that is not easily affected by distortion due to thermal deformation or the like. is there.

In order to achieve the above object, a method for manufacturing a light-emitting element according to an embodiment of the present invention includes: a light-emitting region; and a plurality of device regions each including the light-emitting region and a wiring region adjacent to the light-emitting region in the first axial direction. And a step of producing a substrate arranged in each of a first axial direction and a second axial direction orthogonal to the first axial direction.
A mask having a plurality of linear shielding portions extending in the second axial direction and arranged in the first axial direction, and a plurality of openings formed between the plurality of shielding portions, A plurality of shielding portions cover the wiring regions of each of the plurality of element regions, and are disposed to face the substrate so that the light emitting regions of the plurality of element regions are exposed from the plurality of openings. .
A protective film having a laminated structure of different materials is formed on the substrate through the mask.
The substrate is separated for each element region.

It is a schematic sectional drawing which shows an example of a structure of the light emitting element which concerns on one Embodiment of this invention. It is a schematic top view which shows the structure of the board | substrate which concerns on one Embodiment of this invention. It is a schematic top view which shows the structure of the mask which concerns on one Embodiment of this invention. It is a schematic top view which shows the aspect by which the mask is arrange | positioned on the board | substrate which concerns on one Embodiment of this invention.

A method for manufacturing a light emitting device according to an embodiment of the present invention includes: a light emitting region; and a plurality of device regions each including a light emitting region and a wiring region adjacent to the light emitting region in the first axial direction. A step of fabricating substrates arranged respectively in a second axial direction orthogonal to the first axial direction.
A mask having a plurality of linear shielding portions extending in the second axial direction and arranged in the first axial direction, and a plurality of openings formed between the plurality of shielding portions, A plurality of shielding portions cover the wiring regions of each of the plurality of element regions, and are disposed to face the substrate so that the light emitting regions of the plurality of element regions are exposed from the plurality of openings. .
A protective film having a laminated structure of different materials is formed on the substrate through the mask.
The substrate is separated for each element region.

  Since the mask has a large opening formed along the second axial direction, distortion due to thermal deformation or the like is small. By forming a protective film having a laminated structure of different materials through such a mask, it is possible to form a laminated structure in which the position and shape of the film formation region of each layer are maintained almost constant. For this reason, the protective film can sufficiently exhibit the function of suppressing entry of moisture and the like into the light emitting region. Therefore, the above manufacturing method makes it possible to manufacture a light-emitting element with few defects and a long lifetime.

The protective film forming step may include alternately forming an inorganic film and an organic film.
Such a protective film makes it possible to further suppress entry of moisture or the like into the light emitting layer.

The inorganic film may be formed of, for example, a silicon compound, and more specifically may include at least one of silicon nitride, silicon oxynitride, and silicon oxide.
An inorganic film made of such a material has very low moisture permeability, and thus can more effectively protect the light-emitting element from moisture and suppress deterioration.

The organic film may be formed from an acrylic resin or a polyurea resin. More specifically, the acrylic resin may have ultraviolet curability.
An organic film made of such a material can form a laminated structure with extremely low moisture permeability by being laminated with an inorganic film, and can more effectively protect the light emitting element from moisture and suppress deterioration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of Light Emitting Element]
FIG. 1 is a schematic cross-sectional view illustrating an example of a configuration of a light emitting element. The illustrated light-emitting element 1 includes a substrate 2, a lower electrode layer 3, a hole injection layer 4, a light-emitting layer 5, an electron injection layer 6, an upper electrode layer 7, a plurality of inorganic films 8, and an organic film. 9. The light emitting element 1 as a whole has a laminated structure with a thickness of about 5 μm. In the drawing, the X-axis direction corresponds to the “first axial direction”, the Y-axis direction corresponds to the “second axial direction”, and in the present embodiment, the X-axis direction and the Y-axis direction indicate the horizontal direction. . The Z-axis direction indicates a direction perpendicular to the X-axis direction and the Y-axis direction, and indicates a vertical direction in the present embodiment.

  The substrate 2 is made of, for example, a glass substrate or a plastic substrate. The lower electrode layer 3 is made of a transparent electrode such as indium tin oxide (ITO) or zinc oxide (ZnO) as an anode. The upper electrode layer 7 is made of, for example, aluminum as a cathode. The hole injection layer 4 includes a hole transport layer and injects holes from the lower electrode layer 3 to the light emitting layer 5. The electron injection layer 6 includes an electron transport layer and injects electrons from the upper electrode layer 7 to the light emitting layer 5. The light emitting layer 5 is formed of an organic light emitting material that emits light of a desired color, and emits light by recombination of injected holes and electrons.

  The light emitting element 1 can contain a plurality of light emitting layers 5 inside. The plurality of light emitting layers may be formed in a stripe shape or a grid shape. The plurality of light-emitting layers may include, for example, three types of light-emitting layers of R (red), G (green), and B (blue), whereby a light-emitting element for display use can be configured.

  The shape of the light emitting layer 5 is not particularly limited, and may be configured to extend along the Y-axis direction, for example. The lower electrode layer 3 is formed corresponding to the light emitting layer 5 so that holes can be injected into the light emitting layer 5. A part of the upper electrode layer 7 is disposed on the light emitting layer 5 so that electrons can be injected into the light emitting layer 5 through the electron injection layer 6. In the present embodiment, the upper electrode layer 7 is made of an electrode extending along the X-axis direction. Further, a plurality of upper electrode layers 7 may be provided as necessary, and in that case, they may be periodically arranged in the Y-axis direction.

  A protective film P having a three-layer structure in which inorganic films 8 and organic films 9 are alternately stacked is formed on the upper electrode layer 7. The light emitting layer 5 has the property of being easily deteriorated by moisture, oxygen, and the like. However, by laminating the protective film P, the entry of moisture, oxygen, and the like into the light emitting layer 5 is suppressed.

  The width of the protective film P in the X-axis direction is formed to be narrower than the width of the upper electrode layer 7 and the like in the X-axis direction. This is because a part of the upper electrode layer 7 is configured not to be covered with the protective film P, thereby facilitating connection between the upper electrode layer 7 and a circuit (not shown), for example. In the laminated structure from the substrate 2 to the upper electrode layer 7, a region not covered with the protective film P corresponds to a wiring region 30 described later, and a region covered with the protective film P corresponds to a light emitting region 20 described later. To do.

In the present embodiment, the inorganic film 8 is formed of silicon nitride (SiNx). SiNx has a characteristic that it hardly permeates moisture. Here, with respect to the inorganic film 8 formed of SiNx, the moisture permeability, which is a parameter indicating the amount of water vapor permeated, is measured, for example, about 10 ⁻³ to 10 ⁻⁴ g / m ² / day. The material of the inorganic film 8 is not limited to SiNx, and other silicon nitrides, silicon compounds such as silicon oxynitrides, silicon oxides, and the like can be used.

  In the present embodiment, the organic film 9 is formed of, for example, an acrylic resin having ultraviolet curing properties. The material is not limited to an acrylic resin, and a polyurea resin or the like can be used.

As described above, the protective film P of the present embodiment is composed of a laminated film of the inorganic film 8 made of SiNx or the like and the organic film 9 made of acrylic resin or the like. As a result, the moisture permeability of the protective film P is significantly reduced compared to the moisture permeability of the inorganic film 8 alone. Specifically, the moisture permeability is 10 ⁻⁶ g / m ² / day due to the protective film P according to the present embodiment, which is about 1/100 to 1000 times smaller than that of the inorganic film 8 alone. Become. That is, by using the protective film P that is a laminated film of the inorganic film 8 and the organic film 9, it becomes possible to suppress intrusion of moisture or the like into the light emitting layer 5. The organic film 9 also has a function as a flattening layer, thereby increasing the coverage of the inorganic film 8 and contributing to a decrease in moisture permeability.

  The protective film P is not limited to the structure of this embodiment. For example, a laminated structure of SiNx and silicon oxynitride, a laminated structure of SiNx and silicon oxide, a laminated structure of acrylic resin and polyurea resin, or the like is possible. Further, the number of layers of the inorganic film 8 and the organic film 9 can be increased, and the protective film P can be a laminated film of five layers or more. Further, a configuration in which the uppermost layer is not the inorganic film 8 but the organic film 9 is also possible.

  As will be described later, after the protective film P is formed, the substrate 2 is cut into a predetermined element size, whereby the light emitting element 1 is manufactured. Therefore, the cut surface of the protective film P has a form in which the end faces of the inorganic film 8 and the organic film 9 are aligned as shown in FIG. 1. Even in such a form, the water vapor barrier of the protective film P is provided. It has been confirmed by experiments by the present inventors that the property does not deteriorate.

  Next, a method for manufacturing the light emitting element 1 having the above configuration will be described.

[Method for Manufacturing Light-Emitting Element]
The manufacturing method of the light emitting element 1 includes the following four steps. That is, it includes (1) a substrate manufacturing process, (2) a mask arranging process, (3) an inorganic film and organic film forming process, and (4) a separation process. These will be described in order.

(Manufacturing process of substrate)
In the substrate manufacturing process, the lower electrode layer 3, the hole injection layer 4, the light emitting layer 5, the electron injection layer 6, and the upper electrode layer 7 are formed on the substrate 2. Thus, a “substrate” that is a structure including a plurality of element regions is manufactured. In the following description, a structure that is formed up to the upper electrode layer 7 on the substrate 2 and includes a plurality of element regions is hereinafter referred to as a substrate W.

  As a manufacturing process of the substrate W, first, the substrate 2 is transferred to a chamber or the like (not shown), and the lower electrode layer 3 is formed on the substrate 2. The lower electrode layer 3 can be formed by, for example, a sputtering method, a vapor deposition method, or the like. After the film formation, the lower electrode layer 3 is patterned into a predetermined shape. Next, the hole injection layer 4 is formed on the lower electrode layer 3 by, for example, vapor deposition. The light emitting layer 5 can be formed on the hole injection layer 4 by, for example, a vapor deposition method, and is patterned into a predetermined shape after the film formation. The electron injection layer 6 can be formed on the light emitting layer 5 by, for example, vapor deposition. Furthermore, the upper electrode layer 7 can be formed by, for example, a sputtering method, an evaporation method, or the like, and is patterned into a predetermined shape after the film formation. Each of the layers can be formed in the same chamber or in different chambers.

  As described above, the substrate W having a stacked structure including a plurality of element regions is manufactured. Hereinafter, the structure of the substrate W will be described.

  FIG. 2 is a schematic top view showing the structure of the substrate W. As shown in FIG. In this embodiment, the substrate W has a rectangular plate-like structure including an XY plane orthogonal to the Z-axis direction as a whole, and has a side of, for example, 730 mm to 920 mm. The substrate W is arranged in each of the X-axis direction and the Y-axis direction, and a plurality of element regions 10 partitioned by the scribe lines L are formed. In the present embodiment, as shown in FIG. 2, the scribe line L linearly partitions the element region 10 in the X-axis direction and the Y-axis direction, and each element region 10 has substantially the same configuration and size.

  Each element region 10 has a light emitting region 20 and a wiring region 30. The light emitting regions 20 and the wiring regions 30 are formed adjacent to each other in the X axis direction, and are arranged periodically and alternately in the X axis direction as a whole. In addition, the light emitting region 20 and the wiring region 30 continuously extend along the Y-axis direction so as to cross each element region 10.

  As will be described later, each element region 10 is separated by a scribe line L in a later separation step and becomes a part of the light emitting element 1. Further, the number of element regions 10 formed on the substrate W is not limited to the illustrated example.

  The light emitting region 20 includes the light emitting layer 5. The upper electrode layer 7 is continuously formed along the X-axis direction so as to cross each element region 10 including the light emitting region 20 and the wiring region 30.

  Next, the substrate W having the above structure is transferred into a chamber (not shown), and a mask is placed on the substrate W.

(Mask placement process)
The mask is typically disposed before the substrate W is transported on a mask mounting device or the like installed inside a chamber (not shown). The mask placing device is installed on the upper part of the stage on which the substrate W is placed. When the substrate W is transferred onto the stage, the mask placing device aligns the mask and the substrate W. As described above, the mask is disposed on the substrate W. The chamber used for the mask placement process and the subsequent film formation process is not particularly limited, whether it is a chamber different from the chamber used for manufacturing the substrate W or the same chamber.

  FIG. 3 is a schematic top view of the mask according to the present embodiment, and FIG. 4 is a schematic top view showing an aspect in which the mask is arranged on the substrate W. The mask 40 includes a frame body 41, a plurality of bars (shielding portions) 42, and an opening 43 formed between the plurality of bars 42. The frame body 41 is formed in a rectangular ring shape, and has two sides facing each other in the X-axis direction and two sides facing each other in the Y-axis direction. Of these, the two sides facing each other in the Y-axis direction are defined as a first side 411 and a second side 412, respectively.

  The plurality of bars 42 extend in the Y-axis direction and are arranged in the X-axis direction. In the present embodiment, both ends of each bar 42 are fixed by a plurality of fixing members 44 arranged on the first side portion 411 and the second side portion 412. Moreover, the space | interval between each bar | burr 42, ie, the width | variety of the opening part 43, can be about 3 mm in this embodiment. The thickness of the bar 42 is, for example, 0.05 to 2.0 mm.

  The frame 41 is disposed on the periphery of the substrate W as shown in FIG. As described above, the plurality of bars 42 are fixed by the fixing member 44 so as to cover the wiring area 30, and the opening 43 between the bars 42 exposes the light emitting area 20. In the present embodiment, as shown in FIG. 4, the width of the wiring region 30 in the X-axis direction is substantially the same as that of the bar 42, and the scribe line L extending in the Y-axis direction overlaps with the bar 42. Note that the width of the wiring region 30 in the X-axis direction is equal to or smaller than the width of the bar 42 and the entire surface of the wiring region 30 is covered with the bar 42.

The frame body 41 and the bar 42 of the mask 40 are formed of alumina (Al ₂ O ₃ ) in this embodiment, but the material is not particularly limited. For example, a metal or a heat resistant resin can be used as the other material.

  The mask 40 of this embodiment can suppress a change in the shape of the opening 43 at a high temperature as compared with a mask having a plurality of rectangular openings formed corresponding to the individual light emitting regions 20. If necessary, a tension applying mechanism for pulling the mask 40 in the Y-axis direction that is the extending direction of the bar 42 may be provided. As a result, the shape change of the opening 43 can be further suppressed.

  A method for aligning the substrate W with respect to the mask 40 is not particularly limited. For example, it can be performed while observing an alignment mark placed on the stage with a CCD camera or the like. Further, it can be mechanically performed using a pin structure or the like that is arranged on the stage and defines the position of the substrate W.

  Next, the substrate W is formed through the mask 40 arranged as described above.

(Example of protective film deposition process)
In the film forming process of the substrate W, the inorganic film 8 and the organic film 9 are alternately formed on the light emitting region 20 exposed from the opening 43 through the mask 40. First, the inorganic film 8 is formed on the upper electrode layer 7. The inorganic film 8 is formed by, for example, a CVD method. The mask 40 used for forming the inorganic film 8 and the mask 40 used for forming the organic film 9 may be the same mask or different masks.

  Next, an organic film 9 is formed on the inorganic film 8. The organic film 9 is formed of an acrylic resin having ultraviolet curing properties. The method for forming the organic film 9 is not particularly limited. For example, the organic film 9 is formed by applying an acrylic resin on the inorganic film 8 by spin coating or spraying, and curing the resin by irradiating the applied acrylic resin with ultraviolet rays.

  Subsequently, an inorganic film 8 is formed again on the organic film 9 by CVD, sputtering, or the like. Thereby, a protective film P having a three-layer structure in which the inorganic films 8 and the organic films 9 are alternately stacked is formed on the light emitting region 20 of the substrate W. The organic film 9 has a function as a flattening layer, which can improve the coverage of the inorganic film 8.

In addition, when the inorganic film 8 and the organic film 9 are formed in separate chambers, the mask 40 having the same shape is arranged on the mask placing device or the like arranged in each chamber, The protective film P can be formed.

  Finally, the substrate W on which the protective film P is stacked is separated into a plurality of element regions 10 to manufacture the light emitting element 1.

(Example of separation process)
The substrate W is taken out from the chamber in which the film formation process has been performed, and the element region 10 is separated along the scribe line L in the X-axis direction and the Y-axis direction. Examples of the separation method include, but are not limited to, a dicing saw, a processing technique using a laser, and dry etching. Through this step, the light emitting element 1 is manufactured.

  The light-emitting element 1 having the above-described configuration has a protective film P composed of an inorganic film 8 and an organic film 9 with uniform end faces. This is because, since the mask 40 has the wide opening 43 extending along the Y-axis direction, the deformation of the opening 43 due to thermal deformation or the like is small, so the shape of the film formation region of the inorganic film 8 and the organic film 9 is reduced. This is because it can be held almost constant. Such a protective film P can suppress intrusion of moisture, oxygen, and the like into the light emitting layer 5, and it is possible to manufacture the light emitting element 1 with few defects and a long lifetime.

On the other hand, in a mask having a plurality of rectangular openings corresponding to individual element regions, distortion of the openings due to thermal deformation or the like is likely to occur, and a film cannot be formed in a desired region. In particular, when the substrate is increased in size, the number of element regions included in one substrate is increased, so that the mask requires many openings. Moreover, it becomes more susceptible to thermal deformation due to the increase in size. For this reason, the mask cannot cope with the increase in size of the substrate. Furthermore, when the opening of the mask is distorted or when the NF ₃ gas used as a cleaning gas after the CVD process is corroded, the entire mask must be replaced. The burden of was also heavy.

  When the mask 40 according to this embodiment is used, the opening 43 corresponds to the plurality of element regions 10 and the opening 43 is less distorted due to thermal deformation or the like. Is possible. In addition, since the frame body 41 and the bar 42 are formed of different members, only the necessary bar 42 can be exchanged, and the cost burden can be suppressed.

  Further, since the mask 40 has the wide opening 43, the individual element regions 10 can be efficiently arranged on the substrate W. For this reason, as compared with a mask having a plurality of rectangular openings, it becomes possible to separate many light emitting elements 1 from one substrate W, and it is possible to manufacture each light emitting element 1 at low cost. Become.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  In the above embodiment, the light emitting layer 5 and the like are stacked on the flat substrate 2, but the present invention is not limited to this. For example, a structure in which a plurality of recesses are formed on the substrate 2 and the light emitting layer 5 or the like is formed in the recesses can be employed. In addition, a drive circuit (not shown) or the like can be formed on the substrate 2 as necessary.

  Moreover, the light emitting element 1 demonstrated in the above embodiment can form a glass layer, a transparent film, etc. on the protective film P further. With this structure, the light emitting element 1 can be used as a display device used for a touch panel, for example.

DESCRIPTION OF SYMBOLS 1 ... Light emitting element 3 ... Lower electrode layer 5 ... Light emitting layer 7 ... Upper electrode layer 8 ... Inorganic film 9 ... Organic film 10 ... Element region 20 ... Light emitting region 30 ... Wiring area 40 ... Mask 42 ... Bar (shielding part)
43 ... opening W ... substrate P ... protective film L ... scribe line

Claims (6)

A plurality of element regions each including a light emitting region and a wiring region adjacent to the light emitting region in the first axial direction include a first axial direction and a second axial direction orthogonal to the first axial direction. A substrate arranged in each is manufactured,
A mask having a plurality of linear shielding portions extending in the second axial direction and arranged in the first axial direction, and a plurality of openings formed between the plurality of shielding portions; A plurality of shielding portions cover the wiring regions of each of the plurality of element regions, and are disposed to face the substrate such that the light emitting regions of the plurality of element regions are exposed from the plurality of openings.
Forming a protective film having a laminated structure of different materials on the substrate through the mask,
A method for manufacturing a light-emitting element, wherein the substrate is separated for each element region. It is a manufacturing method of the light emitting element according to claim 1,
The step of forming the protective film includes alternately forming an inorganic film and an organic film. It is a manufacturing method of the light emitting element according to claim 2,
The inorganic film is made of a silicon compound. It is a manufacturing method of the light emitting element according to claim 3,
The method for manufacturing a light emitting device, wherein the silicon compound includes at least one of silicon nitride, silicon oxynitride, and silicon oxide. It is a manufacturing method of the light emitting element according to claim 2,
The method for manufacturing a light emitting device, wherein the organic film is made of an acrylic resin or a polyurea resin. It is a manufacturing method of the light emitting element according to claim 5,
The said acrylic resin is a manufacturing method of the light emitting element which has ultraviolet curing property.

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