JPH11297471A - Manufacture of electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the manufacturing method for an electroluminecence element, in which processing precision of an electrode formed by using a hard mask is improved. SOLUTION: A first segment electrode 16 is deposited and formed on an organic electroluminescence layer 22 using a first hard mask 11. A second segment electrode 17, and a third segment electrode 18 are similarly formed sequentially on the organic electroluminescence layer 22 with the use of a second hard mask 12 and a third hard mask 13. An extension wiring 19, including connection wirings to be connected to these segment electrodes 16, 17, 18 respectively, is formed using another hard mask. A high precision electrode pattern can thus be formed, while achieving mask strength by using plural hard masks disposed to the electrode pattern separated. As a result, the generation of nonconformities such as unnecessary lighting can thus be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an electroluminescent device.

[0002]

2. Description of the Related Art Hitherto, as an electroluminescent device, a device in which a light emitting layer made of an electroluminescent (hereinafter referred to as EL) material is sandwiched between a signal electrode and a scanning electrode is known. As a display method of such an electroluminescent device, there are a character display by a segment and a dot display by a matrix, which are roughly classified.

[0003] In recent years, an organic electroluminescent device using an organic EL material for a light emitting layer has been receiving attention. As shown in FIG. 12, an anode (signal electrode) 3 formed on the lower surface of a transparent substrate 2 is joined to one surface of a light emitting layer 1 as an organic electroluminescent device for displaying a character.
Has a structure in which a cathode electrode (scanning electrode) 4 is joined to the other surface of the. The anode electrode 3 and the cathode electrode 4 are formed on the basis of the character shape to be displayed (the shape forming a numeral in FIG. 12). Also,
The anode electrode 3 and the cathode electrode 4 are provided with lead wires 3A and 4A, respectively, for connection to the outside, and are formed so that the lead wires 3A and 4A do not overlap via the light emitting layer 1. .

In the manufacturing process of such an organic electroluminescent device, to form the anode electrode 3, for example, a transparent ITO (indium tin oxide) film is formed on the transparent substrate 2, and this ITO film is subjected to photolithography. Patterning is performed using technology. On the other hand, in order to easily inject electrons into the light emitting layer 1, the cathode electrode 4 employs a method of evaporating a metal having a low work function in a vacuum. That is, in order to form the cathode electrode 4 and the lead wiring 4A, a hard mask (metal plate) 5 having an opening in an arbitrary pattern is arranged between the evaporation source 7 and the light emitting layer 1 as shown in FIG. Deposition. At this time, an area other than the opening 5A of the hard mask 5 blocks unnecessary deposition. Therefore, the shape of the cathode electrode depends on the shape of the hard mask opening 5A.

[0005]

However, the hard mask 5 has a problem that the strength thereof decreases as the area of the opening 5A increases. As shown in FIG. 13, when the opening portion 5A of the hard mask 5 is complicated and the opening area increases, the strength is extremely low particularly at the joint portion 5B between the opening portions 5A,
There is a problem that the hard mask 5 easily bends when placed on the mask stage 6. The hard mask 5 shown in FIG. 14 is indicated by a broken line when the opening area is relatively small, and the hard mask 5 indicated by a solid line is when the opening area is large and a complicated pattern is formed. Is shown.

Further, when the hard mask is finely processed, if the opening width of the mask is longer than the thickness of the mask, the portion around the opening is bent and the cathode electrode 4 and the lead-out wiring 4A, which are the deposition portions, are formed. However, there is a problem that desired processing accuracy cannot be obtained. When the processing accuracy cannot be obtained, if the lead wiring 4A overlaps with the lead wiring 3A on the anode electrode 3 side via the light emitting layer 1,
There is a problem that unintended light emission occurs at that portion. The value of the aspect ratio can be kept low by reducing the thickness of the mask. However, the limit is about 0.1 mm because of the strength of the mask itself. Therefore, since the minimum value of the mask plate thickness is about 0.1 mm, the minimum line width of the cathode electrode 4 and the lead wiring 4A that can be formed is about 0.1 mm. However, even if the minimum dimension is satisfied at 0.1 mm, it is clear that if the opening area of the hard mask is large or the supporting portion supporting the space between the openings is extremely narrow, the strength of the mask is correspondingly deteriorated. In addition, the strength cannot be discussed only with the numerical value satisfied by the plate thickness.

An object of the present invention is to provide a method of manufacturing an electroluminescent device which can increase the strength of a hard mask when forming a cathode electrode composed of complicated segments and can improve the processing accuracy of the cathode electrode. It is an object. Another object of the present invention is to provide a method for manufacturing an electroluminescent device that can prevent light emission from occurring at an unintended part.

[0008]

According to the first aspect of the present invention,
A method for manufacturing an electroluminescent element in which a light-emitting layer containing an EL material is sandwiched between electrodes, wherein a plurality of hard masks provided by dividing an electrode pattern formed on one surface of the light-emitting layer are used. An electrode material is sequentially deposited on one surface of the light emitting layer.

According to the first aspect of the present invention, since the electrode pattern is divided by a plurality of hard masks, an opening for forming an electrode formed in one hard mask has a smaller relative area, and the mask strength of the hard mask is reduced. Can be improved. For this reason, the bending of the hard mask can be suppressed,
Thereby, the pattern accuracy of the electrode formed can be improved. Further, by dividing the pattern, it is possible to miniaturize the formed pattern. further,
Since the processing accuracy of the lead wiring formed together with the electrode is also increased, it is possible to suppress the overlap of the lead wiring of the electrode formed on the opposite side with the light emitting layer therebetween, and to suppress unintended unnecessary light emission. .

According to a second aspect of the present invention, there is provided the method for manufacturing an electroluminescent device according to the first aspect, wherein the light emitting layer is made of an organic electroluminescent material.

According to a third aspect of the present invention, in the method for manufacturing an electroluminescent device according to the first or second aspect, the electrode formed on one surface of the light emitting layer is a cathode electrode. Features.

According to the third aspect of the present invention, by forming the cathode electrode using a plurality of hard masks, it is possible to form a pattern with high accuracy without using photolithography technology.

According to a fourth aspect of the present invention, in the method for manufacturing an electroluminescent device according to any one of the first to third aspects, the electrode formed on the other surface of the light emitting layer is made of a transparent conductive material. It is characterized by being made of a material and being patterned by a photolithography technique and an etching technique.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a method for manufacturing an electroluminescent device according to the present invention will be described below based on an embodiment shown in the drawings. (Embodiment 1) FIGS. 1 to 4 are perspective views showing Embodiment 1 of a method for manufacturing an electroluminescent device according to the present invention. In addition,
This embodiment is an example in which the present invention is applied to an electroluminescent device having a segment portion capable of displaying a three-digit number.

In this embodiment, as shown in FIGS. 1 to 4, a first hard mask 11 and a second hard mask 1 are formed.
2, a third hard mask 13 and a fourth hard mask 14 are prepared. First hard mask 11, second hard mask 1
The second and third hard masks 13 are formed with a first segment opening 11A, a second segment opening 12A, and a third segment opening 13A, each of which can display a digit of each digit. Further, the fourth hard mask 14 is formed with a lead-out wiring opening 14A for forming a wiring connected to a constituent electrode of a segment portion for displaying a digit of each digit.

Next, a method for manufacturing an electroluminescent device using these hard masks will be described. First, a transparent substrate 20 on which an anode electrode 21 and an organic EL layer 22 are previously deposited is disposed as a substrate to be deposited in a chamber of a vapor deposition apparatus. The first hard mask 11 is disposed close to the organic EL layer 22 therebetween. Thereafter, a metal having a low work function is deposited in a vacuum, and a first segment having the same shape as the first segment opening 11A of the first hard mask 11 as shown in FIG. The electrode 16 is formed of a low work function material such as Mg or an Mg alloy. The anode electrode 21
Is patterned in advance using a photolithography technique after forming an ITO film, for example.

Thereafter, instead of the first hard mask 11, a second hard mask 12 is arranged so as to face the organic EL layer 22, and the same deposition is performed to form a second segment electrode 17 as shown in FIG. It is formed of a low work function material such as Mg or Mg alloy. Next, instead of the second hard mask 12, a third hard mask 13 is disposed so as to face the organic EL layer 22, and the same vapor deposition is performed to perform the third hard mask 13 as shown in FIG.
The segment electrode 18 is formed of a low work function material such as Mg or an Mg alloy. In this way, a pattern of an electrode portion for displaying a three-digit number can be formed.

Next, as shown in FIG. 4, the fourth hard mask 14 is arranged so as to face the organic EL layer 22 and is subjected to vapor deposition to form lead-out wirings (including connection wirings for connecting segments). ) 19 is formed. As a result, as shown in FIG.
In addition, a lead wire 19 connected to these electrodes is formed, and a cathode-side electrode can be formed. Note that the lead wiring 19 may be made of a material having a low work function such as Mg or a Mg alloy or a material having a high work function such as Al as long as it has a low resistance. Then, a sealing film having low water and oxygen permeability is formed on the first, second, and third segment electrodes 16, 17, 18, the lead-out wiring 19, and the EL layer.

In this embodiment, the first, second, and third segment electrodes 16, 17, and 18 as the cathode electrodes and the lead-out wiring 19 are formed using four hard masks. As a result, the area of the opening in each hard mask becomes small, and a decrease in mask strength can be suppressed. Therefore, even when a hard mask is placed on the mask stage during vapor deposition, the amount of deflection of the mask can be suppressed, and the processing accuracy can be improved. In the above embodiment, the first, second, and third segment electrodes 16, 17, and 18 and the lead-out wiring 19 are formed on the organic EL layer 22 formed on the transparent substrate 20, but as described above on the insulating substrate. First, second, and third segment electrodes 16, 17, and 18 and lead-out wiring 19 are formed, and the insulating substrate is appropriately bonded to a transparent substrate 20 on which an anode electrode 21 and an organic EL layer 22 are formed. May be.

(Embodiment 2) FIGS. 5 and 6 show the configuration of a plurality of hard masks used in Embodiment 2 of the method for manufacturing an electroluminescent device according to the present invention. FIG. 5A shows the first
The hard mask 23 is shown. In the first hard mask 23, a first opening 23A is formed in which a part of patterns of the first and second digit segments and a pattern of a wiring portion connecting them are opened. FIG. 5B shows the second hard mask 24. This second hard mask 24
, A second opening 24 </ b> A opening with a part of the pattern of the third digit segment and the pattern of the lead wiring connected thereto. FIG. 5C shows the third hard mask 25. The third hard mask 25 includes:
Third opening 2 in which a part of the patterns of the first and second digit segments and the pattern of the wiring portion connecting them are opened
5A are formed. FIG. 6A shows the fourth hard mask 26. The fourth hard mask 26 includes:
A fourth opening 26 in which a part of the pattern of the third digit segment and the pattern of the lead wiring connected thereto are opened.
A is formed. FIG. 6B shows the fifth hard mask 27. The fifth hard mask 27 has a fifth opening 27A in which a partial pattern of each segment, a pattern of a wiring portion connecting these segments, and a pattern of a lead wiring are opened. By combining the openings formed in the first to fifth hard masks 23, 24, 25, 26, and 27, the entire pattern of the cathode electrode can be formed.

The other manufacturing steps in this embodiment are the same as those in the first embodiment. Also in this embodiment, the pattern is dispersed in each hard mask, and the area of the opening in each hard mask is small,
Further, since there is no seam portion 5B as shown in FIG. 13, a decrease in mask strength can be suppressed. For this reason, even when the hard mask is placed on the mask stage during the vapor deposition, the amount of deflection of the mask is small, so that the processing accuracy of the electrode pattern can be improved. In the above embodiment, the first, second, and third segment electrodes 16, 17, and 18 and the lead-out wiring 19 are formed on the organic EL layer 22 formed on the transparent substrate 20, but as described above on the insulating substrate. First, second, and third segment electrodes 16, 17, and 18 and lead-out wiring 19 are formed, and the insulating substrate is appropriately bonded to a transparent substrate 20 on which an anode electrode 21 and an organic EL layer 22 are formed. May be.

(Embodiment 3) FIG. 7 shows Embodiment 3 of a method for manufacturing an electroluminescent device according to the present invention. First,
In the present embodiment, an organic EL is formed on the surface of the transparent substrate 20 on which the anode electrode 21 is formed, as in the first embodiment.
The layer 22 is formed by a method such as evaporation or spin coating,
The first hard mask 11 and the second hard mask 11 are formed on the organic EL layer 22.
The first segment electrode 16, the second segment electrode 17, and the third segment electrode 18 are formed using the hard mask 12 and the third hard mask 13.

The lead wiring 19 is formed on the insulating substrate 15 by using the fourth hard mask 14 of the first embodiment.
To form Further, the lead wiring 1 is formed so as to correspond to each segment electrode formed on the organic EL layer 22.
9 and the conductive connecting members 28 to 2
After forming 8, the transparent substrate 20 and the insulating substrate 15 are appropriately adjusted in position and stuck together. At this time, the substrates 15 and 20 may be joined with a sealing material (not shown). FIG. 8 is a cross-sectional view of a main part showing a state in which the segment electrode 16 (17, 18) and the extraction electrode 19 are connected via the connecting member 28. As can be seen from the figure, since the lead-out wiring 19 does not directly contact the organic EL layer 22, it is possible to prevent unnecessary lighting at the overlapping portion between the lead-out wiring 19 and the anode electrode 21. .

In the present embodiment, since the segment electrode (cathode electrode) portion serving as the lighting portion is separated from the lead-out wiring portion via the connecting member 28, the degree of freedom in designing the lead-out wiring increases. That is, even if a pattern in which the other non-conducting segment electrode portion and the lead-out wiring overlap with each other, there is no space between them, so that no short circuit occurs and unintended lighting does not occur.

(Embodiment 4) FIG. 9 shows Embodiment 4 of a method for manufacturing an electroluminescent device according to the present invention. First,
In the present embodiment, an organic EL is formed on the surface of the transparent substrate 20 on which the anode electrode 21 is formed, as in the first embodiment.
The layer 22 is formed by a method such as evaporation or spin coating,
The first hard mask 11 and the second hard mask 11 are formed on the organic EL layer 22.
The first segment electrode 16, the second segment electrode 17, and the third segment electrode 18 are formed using the hard mask 12 and the third hard mask 13.

The insulating substrate 15 is formed on the lead wiring 19 by using the fourth hard mask 14 of the first embodiment.
To form Further, the lead wiring 1 is formed so as to correspond to each segment electrode formed on the organic EL layer 22.
9 and the conductive connecting members 28 to 2
8 is formed. Then, in the present embodiment, an insulating film 29 for separating the first to third segment electrodes 16 to 18 and the lead-out wiring 19 is formed. In the insulating film 29, through holes 29A to 29A for conducting the segment electrode portion and the lead-out wiring portion with the connecting member 28 are formed, and the connecting members 28 to 28 are exposed from the through holes 29A to 29A. After that, the first segment electrode 16, the second segment electrode 17, and the third segment electrode 18 are formed on the insulating film 29 as in the first or second embodiment. In the above embodiment, the connection members 28 to
After forming the insulating film 29, the connecting member 28 is formed in the through holes 29A to 29A.
~ 28 may be filled.

(Embodiment 5) FIGS. 10 and 11 show Embodiment 5 of a method for manufacturing an electroluminescent device according to the present invention. First, in the present embodiment, the organic EL layer 22 is formed on the surface of the transparent substrate 20 on which the anode electrode 21 is formed by a method such as vapor deposition or spin coating as in the first embodiment.

Next, the lead wiring 1 is formed on the insulating substrate 15 by using the fourth hard mask 14 of the first embodiment.
9 is formed. After that, the first insulating layer 30 is formed on the transparent substrate 20 on which the lead wiring 19 has been formed. afterwards,
A through hole 30A is opened at a predetermined position of the first insulating layer 30, and the connection member 28 is filled in the through hole 30A.
Next, the first segment electrode 16, the second segment electrode 17, and the third segment electrode 18 are formed as in the first embodiment or the second embodiment. Then, the second insulating layer 31 having the first segment opening 31A, the second segment opening 31B, and the third segment opening 31C is deposited. The substrate 15 and the substrate 20 are attached to each other, and the first segment electrode 16, the second segment electrode 17, and the third segment electrode 18 exposed from the first segment opening 31A, the second segment opening 31B, and the third segment opening 31C are formed. Then, they are bonded so as to be in close contact with the organic EL layer 22. FIG. 11 is a sectional view of a main part of the electroluminescent device.
For this reason, the light emitting region is formed by the opening 31A of the second insulating layer 31,
31B, 31C. In the above embodiment, the first segment electrode 16 and the second segment electrode 1
7 and the third segment electrode 18 are formed, and then the second insulating layer 3 is formed.
1, but after providing the second insulating layer on the first insulating layer 30 in which the connection member 28 is filled in the through hole 30A,
The first segment opening 31A and the second segment opening 31A are formed in the second insulating layer 31 by using photolithography technology and etching technology.
Segment opening 31B, third segment opening 31C
Is patterned. Then, after a cathode electrode material film is formed on the entire surface of the second insulating layer 31, an etch back is performed, and the cathode electrode material film (the first segment electrode 16, the second segment electrode 16, 1
7. The third segment electrode 18) is formed so as to remain. Next, an electroluminescent element may be formed by bonding the thus formed cathode electrode material film on the transparent substrate 20 side and the organic EL layer 22 so as to be bonded.

Therefore, the first segment opening 31
A, since the second segment opening 31B and the third segment opening 31C are formed in the second insulating layer 31 by using the photolithography technique and the etching technique, the first segment electrode 16 joined to the organic EL layer 22 is formed. Second
The segment electrode 17 and the third segment electrode 18 can be formed with high accuracy. In the present embodiment, since only the lead wiring 19 is formed using the hard mask, the shape of the opening formed in the hard mask can be simplified, and the area of the opening can be reduced with respect to the hard mask. In addition, a decrease in mask strength can be suppressed. For this reason, even when the hard mask is placed on the mask stage during the deposition of the lead wiring 19, the amount of deflection of the mask is small and the processing accuracy of the wiring pattern can be improved. In the present embodiment, the lead wiring 19 is formed on the transparent substrate 20 by vapor deposition using the fourth hard mask 14. However, after forming the ITO film on the transparent substrate 20, the photolithography technology and the etching technology are used. And a method of performing patterning using the same.

Although the first to fifth embodiments have been described above, the present invention is not limited to these, and various modifications accompanying the gist of the configuration are possible. For example, in each of the above-described embodiments, the present invention is applied to the formation of the segment electrodes. However, the present invention can be applied to the manufacture of an electroluminescent element for performing dot display. In the above embodiment, the organic EL material is used for the light emitting layer.
It goes without saying that the present invention can be applied even when a material is used.

[0031]

As is clear from the above description, according to the present invention, the strength of the hard mask can be increased,
Processing accuracy of an electrode formed using a hard mask can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a manufacturing process of a first embodiment of a method for manufacturing an electroluminescent device according to the present invention.

FIG. 2 is a perspective view showing a manufacturing process of the first embodiment.

FIG. 3 is a perspective view showing a manufacturing process of the first embodiment.

FIG. 4 is a perspective view showing a manufacturing process of the first embodiment.

FIGS. 5A to 5C are perspective views showing a hard mask according to a second embodiment of the method for manufacturing an electroluminescent element according to the present invention.

FIGS. 6A and 6B are perspective views showing a hard mask according to a second embodiment.

FIG. 7 is a perspective view showing Embodiment 3 of the method for manufacturing the electroluminescent element according to the present invention.

FIG. 8 is a sectional view of a main part of an electroluminescent element according to a third embodiment.

FIG. 9 is a perspective view showing Embodiment 4 of the method for manufacturing the electroluminescent element according to the present invention.

FIG. 10 is a perspective view showing Embodiment 5 of the method for manufacturing the electroluminescent element according to the present invention.

FIG. 11 is a sectional view of a main part of an electroluminescent element according to a fifth embodiment.

FIG. 12 is an exploded perspective view showing a conventional electroluminescent element.

FIG. 13 is a perspective view showing a deposition step using a conventional hard mask.

FIG. 14 is an explanatory sectional view showing a bent state of a conventional hard mask.

[Explanation of symbols]

 11 First hard mask 11A First segment opening 12 Second hard mask 12A Second segment opening 13 Third hard mask 13A Third segment opening 14 Fourth hard mask 14A Third segment opening 15 Insulating substrate 16 First Segment electrode 17 Second segment electrode 18 Third segment electrode 19 Leader electrode 20 Transparent substrate 21 Anode electrode 22 Organic EL layer

Claims (4)

[Claims] 1. A method of manufacturing an electroluminescent device comprising a light emitting layer containing an electroluminescent material sandwiched between electrodes, wherein a plurality of hard disks are provided in which a pattern of an electrode formed on one surface of the light emitting layer is divided. A method for manufacturing an electroluminescent device, comprising sequentially depositing an electrode material on one surface of the light emitting layer using a mask. 2. The method according to claim 1, wherein the light emitting layer is made of an organic electroluminescent material. 3. The method according to claim 1, wherein the electrode formed on one surface of the light emitting layer is a cathode electrode. 4. The electrode according to claim 1, wherein the electrode formed on the other surface of the light emitting layer is made of a transparent conductive material, and is patterned by a photolithography technique and an etching technique. A method for manufacturing the electroluminescent device according to any one of the above.