JPH08298184A - Manufacture of electroluminescence element - Google Patents

Abstract

PURPOSE: To prevent damage to an emitting layer by avoiding the infiltration of an etching fluid in the emitting layer at wet etching, even when a pinhole, crack, etc., are developed in the second insulating layer, in the case of forming the emitting layer with alkali earth metal sulfide or alkali earth metal selenide of SrS or the like serving as the base material. CONSTITUTION: When take-out electrodes 17 are wet-etched, a jig is used so as to prevent placing an emitting layer forming region 30 in an etching fluid 41. This jig has a tubular member 50 of shape and size larger than the emitting layer forming region 30, to mount an O ring 51 in a contact surface with a substrate 11 so as to prevent the etching fluid from infiltrating into the emitting layer forming region 30. Under a condition where this jig is pressed to the substrate 11, the etching fluid 41 is injected in a vessel 40 to only outside the jig.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electroluminescence (hereinafter referred to as EL) element used for, for example, self-luminous segment display or matrix display of instruments, or display of various information terminal devices. .

[0002]

2. Description of the Related Art Conventionally, an EL element has a first substrate composed of an optically transparent ITO film or the like on a glass substrate which is an insulating substrate.
An electrode, a first insulating layer made of Ta ₂ O ₅ (tantalum pentoxide), etc., a light emitting layer, a second insulating layer, and a second electrode are sequentially laminated. Further, a lead-out electrode made of Ni (nickel) or the like which can be soldered is formed for wiring of the EL element and the drive circuit.

For the light emitting layer, ZnS is used as a base material, and Mn (manganese), Tb (terbium), and S are used as emission centers.
A material to which m (samarium) is added, or a material to which SrS (strontium sulfide) is added as a base material and Ce (cerium) is added as an emission center is used.

[0004]

In order to enable fine display in a conventional EL device, it is necessary to finely process the first electrode, the second electrode, and the take-out electrode to the drive circuit, which is usually wet etching. To form a predetermined pattern. However, if there are pinholes, cracks, etc. in the second insulating layer of the EL element, water penetrates through them and an etching solution (water-soluble) during wet etching occurs therein. Here, when the light emitting layer is formed by using an alkaline earth metal sulfide such as SrS or an alkaline earth metal selenide as a base material, when water enters the light emitting layer, the light emitting base material and water react, Causes fatal damage to the light emitting layer itself.

The present invention has been made in view of the above problems, and when an alkaline earth metal sulfide or an alkaline earth metal selenide is used as a base material to form a light emitting layer, a pinhole is formed in the second insulating layer. Even if a crack or the like occurs, it is an object to prevent the etching liquid from entering the light emitting layer during wet etching and prevent damage to the light emitting layer.

[0006]

In order to achieve the above-mentioned object, the present invention is characterized in that the extraction electrode is patterned by wet etching while the light emitting layer forming region is isolated from the etching solution. As a result, even when the light emitting layer is formed by using the alkaline earth metal sulfide or the alkaline earth metal selenide as the base material, the light emitting layer forming region is kept in the etching solution during the wet etching of the extraction electrode. Since it is not soaked, it is possible to prevent the etching liquid from entering the light emitting layer during wet etching and prevent damage to the light emitting layer.

Further, according to the present invention, after forming both the second electrode and the extraction electrode, a resist pattern is formed on the film formation region, and the second electrode and the extraction electrode are patterned using this resist pattern. Is characterized by. Thus, both the second electrode and the extraction electrode can be simultaneously patterned with one resist pattern, and the patterning process can be simplified.

The second electrode in the light emitting layer forming region can be patterned by dry etching, and reactive dry etching can be used as the dry etching. Further, the extraction electrode to the drive circuit can be formed by using the second electrode, but can also be formed by at least one layer of metal film in addition to the second electrode. In that case, a transparent electrode of ZnO or ITO can be used as the second electrode.

Further, the present invention is characterized by using an instrument constituted by a tubular member having a seal member such as an O-ring at an end thereof during the above wet etching.
With this device, the insulating substrate is pressed and fixed in the container,
When the etching liquid is injected into the container, the etching liquid is prevented from entering the tubular member. Therefore, it is possible to prevent the etching solution from entering the light emitting layer during wet etching.

[0010]

【Example】

(First Embodiment) The present invention will be described below with reference to specific embodiments. FIG. 1 is a schematic view of a cross section of an EL element 10 according to the present invention. In the EL element 10 of FIG. 1, light is extracted in the arrow direction.

The thin film EL element 10 comprises a glass substrate 11 which is an insulative substrate and a first optically transparent ITO film.
Transparent electrode (first electrode) 12, Ta ₂ O ₅ formed of the first insulating layer 13, Ce emitting layer 14 made of SrS added as a luminescent center, Ta ₂ O consists of ₅ second insulating layer 15 and the optically The second electrode 16 made of transparent zinc oxide (ZnO) is sequentially laminated and formed.

The thickness of each layer is such that the first and second transparent electrodes 12,
16 is 300 nm, respectively, the first and second insulating layers 13 and 1
5 is 400 nm, and the light emitting layer 14 is 800 nm. The film thickness of each of these layers is based on the central portion of the glass substrate 11. Next, the thin film EL element 10
The manufacturing method of will be described. First, the first transparent electrode 12 made of ITO was formed on the glass substrate 11 which is an insulating substrate by a sputtering method. After that, a resist was applied to the entire surface of the substrate, and a predetermined resist pattern was formed using a mask having a predetermined pattern. Next, the first electrode was patterned into a predetermined pattern by immersing it in an etching solution containing HCl (hydrochloric acid). Then, the resist was removed.

Next, Ta _{2 is formed} on the first transparent electrode 12.
The first insulating layer 13 made of O ₅ was formed by the sputtering method. Then, on the first insulating layer 13, SrS: Ce containing SrS as a base material and Ce added as an emission center is added.
The (strontium sulfide: cerium) light emitting layer 14 was formed by the sputtering method. On this light emitting layer 14, Ta ₂ O ₅
The second insulating layer 15 consisting of was formed in the same manner as the above-mentioned first insulating layer 13. This state is shown in FIG. 2 to 4, the left side is a schematic view of a cross section, and the right side is a schematic view of a plane.

Then, the second transparent electrode 1 made of a ZnO film
6 is formed on the second insulating layer 15 by the ion plating method (FIG. 2B), a resist is applied on the second transparent electrode 16, and a predetermined resist pattern 21 is formed using a mask having a predetermined pattern. Formed (FIG. 2 (C)). afterwards,
The second transparent electrode 16 was patterned into a predetermined pattern by reactive dry etching using CH ₃ (methane) gas, and the unnecessary resist was removed by dry etching using oxygen plasma (FIG. 3A).

Then, a take-out electrode 17 made of Ni (nickel) is formed by a sputtering method on the connection portion to the second transparent electrode 16 and the driving circuit and the like (FIG. 3 (B)), and then the second electrode.
A predetermined resist pattern 22 was formed similarly to the transparent electrode 16 (FIG. 3 (C)). Next, the extraction electrode 17 was patterned by wet etching (FIG. 3).
(D)). At this time, the region where the light emitting layer 14 was formed (light emitting layer forming region) was not put in the etching solution for the extraction electrode, but only the extraction electrode portion was dipped in the etching solution to form a pattern.

Specifically, in order to immerse only the extraction electrode 17 in the etching solution and prevent the light emitting layer forming region from being immersed in the etching solution, a jig (etching solution invasion preventing device) shown in FIG. 4 is used. Using. This jig has a tubular member 50 having a quadrangular cross section that is slightly larger than the light emitting layer forming region 30, and an O-ring 51 is provided on the contact surface with the substrate 11 so that the etching liquid does not enter the light emitting layer forming region 30. Is attached. While the jig was pressed against the substrate 11, the etching liquid 41 was injected into the container 40 only outside the jig. The upper part of the figure shows a cross section, and the lower part shows a planar state.

A vacuum chuck may be used as a method for pressing the jig. The shape and structure of the jig are not particularly limited as long as they can prevent the etchant from entering the light emitting layer forming region. By using this method, it is not necessary to immerse the light emitting layer forming region in the etching liquid, and damage to the light emitting layer can be suppressed. (Second Embodiment) The second transparent electrode 16 is formed in the same manner as in the first embodiment, and before the second transparent electrode 16 is patterned, the extraction electrode 17 is formed in a predetermined region in the same manner as in the first embodiment. It was formed by the method (FIG. 5 (A)).

Next, the second transparent electrode 16 and the extraction electrode 1
A resist pattern 23 that can be used in common with the pattern 7 was formed. (FIG. 5 (B)). After forming the resist pattern 23, the extraction electrode 17 was patterned by wet etching. At this time, as shown in FIG. 6, the substrate was held vertically, only the film formation region of the take-out electrode 17 was put in the etching liquid 41, and the light emitting layer forming region 30 was kept outside the etching liquid. Also, the splashing of the etching solution was taken into consideration to prevent the splashed solution from sticking.

Next, the second transparent electrode 16 was patterned by reactive dry etching using the same resist pattern 23 as in the first embodiment (FIG. 5C). Even when this method is used, the light emitting layer forming region 30 can be prevented from being immersed in the etching solution, and damage to the light emitting layer can be suppressed. Further, when this method is used, there is a cost advantage that only one photomask is required for the patterning process of the second transparent electrode 16 and the extraction electrode 17.

In the second embodiment, the wet etching of the take-out electrode 17 may be carried out by using the jig shown in FIG. Further, in the above-described embodiment, the extraction electrode 17 is made of a material different from that of the second transparent electrode 16, but the end of the second transparent electrode 16 may be used as the extraction electrode. Further, the extraction electrode 17 may be composed of a plurality of layers.

Further, the materials used for the respective constituent elements of the EL element 10 are not limited to those described above, and for example, the first and second transparent electrodes 12 and 16 are both ITO and Z.
You may make it comprised by nO. Further, the alkaline earth metal sulfide as the base material of the light emitting layer is
Besides, CaS and BaS can be used. Also,
Examples of alkaline earth metal selenides include CaSe and Ba.
Se and SrSe can be used.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of an electroluminescence element.

FIG. 2 is a diagram showing a manufacturing process of the electroluminescent element in the first example.

FIG. 3 is a diagram showing a step that follows FIG.

FIG. 4 is an explanatory diagram for explaining a state of performing wet etching in the first embodiment.

FIG. 5 is a diagram showing a partial manufacturing process of the electroluminescent element in the second embodiment.

FIG. 6 is an explanatory diagram for explaining a state in which wet etching is performed in the second embodiment.

[Explanation of symbols]

Reference numeral 10 ... EL element, 11 ... Glass substrate, 12 ... First transparent electrode, 13 ... First insulating layer, 14 ... Light emitting layer, 15 ... Second insulating layer, 16 ... Second transparent electrode, 17 ... Extraction electrode.

Claims (7)

[Claims] 1. A first light emitting layer is formed on the insulating substrate in a region where the light emitting layer is formed.
In a method for manufacturing an electroluminescent element by laminating an electrode, a first insulating layer, a light emitting layer, a second insulating layer and a second electrode, and further forming a lead electrode to a drive circuit, the light emitting layer is formed of alkaline earth. A metal sulfide or an alkaline earth metal selenide is formed as a base material, and the extraction electrode is patterned by wet etching in a state where the light emitting layer forming region is isolated from an etching solution. Production method. 2. A method of forming a resist pattern on a film formation region after forming both the second electrode and the extraction electrode, and patterning the second electrode and the extraction electrode using the resist pattern. The method for manufacturing an electroluminescent element according to claim 1, wherein. 3. The method for manufacturing an electroluminescent element according to claim 1, wherein the second electrode in the light emitting layer forming region is patterned by dry etching. 4. The method of manufacturing an electroluminescent element according to claim 3, wherein the dry etching is reactive dry etching. 5. The method for manufacturing an electroluminescence element according to claim 1, wherein the extraction electrode is formed of at least one metal film. 6. The method for manufacturing an electroluminescence device according to claim 1, wherein the second electrode is a transparent electrode made of ZnO or ITO. 7. An instrument used during the wet etching in the method for manufacturing an electroluminescent element according to claim 1, wherein the light emission is in a container into which the etching solution is injected. A tubular member that presses and fixes the insulating substrate in the peripheral portion of the layer forming region, and when the etching solution is injected into the container, the tubular member is provided at an end portion of the tubular member where the pressing and fixing is performed, An etching solution intrusion prevention device used for manufacturing an electroluminescence device, comprising: a seal member that prevents the etching solution from entering the tubular member.