JPS62115123A - Electrode substrate for display element - Google Patents

Abstract

PURPOSE:To prevent the generation of a short circuit, etc. in the shoulder part of transparent electrodes by laminating an insulating film on a substrate and transparent electrodes in the state of flattening the to surface thereof. CONSTITUTION:A thin film EL display element is constituted by successively laminating the transparent electrodes 12, the insulating film 13, EL light emitting film 14, the insulating film 15 and a counter electrode 16 on the substrate 11. The insulating film 13 covers the surface of the substrate 11 and the transparent electrodes 12 and the top surface thereof is flattened. The stop of the insulating film in the shoulder part of the transparent electrodes 12 is, therefore, eliminated and the EL light emitting film 14, insulating film 15 and counter electrode 16 formed on the insulating film 13 are respectively flatly formed. The transparent electrodes are thus thoroughly covered by the insulating film 13, by which the generation of the short circuit is considerably decreased and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrode substrate for various display elements such as EL display elements and liquid crystal display elements.

``Prior art and its problems'' In various display elements such as EL display elements and liquid crystal display elements, a patterned transparent electrode is formed on a substrate such as glass, and an insulating film is further laminated on the substrate. It is used.

To explain a conventional thin film EL display element, as shown in FIG. 7, a transparent electrode 2 made of an ITO film or the like is formed in a pattern on a glass substrate l, and on the substrate l and the transparent electrode 2, An insulating film 3 is formed. Further, on the insulating film 3, an EL light emitting device, an insulating film 5, and a counter electrode 8 are sequentially laminated to form a device. This thin film E
The L display element has several tens of layers between the transparent electrode 2 and the counter electrode 6.
By applying an alternating current electric field of Hz to several KHz, E
The active species ions in the L-light emitting film 4 are excited and emit light.

However, in a thin film EL display element like the one described in -h,
When forming the insulating film 3 on the substrate 1 and the transparent electrode 2,
Since the insulating film 3 is laminated with a uniform thickness, a step is formed on the shoulder portion 2a of the transparent electrode 2. This step also remains as it is on the EL light emitting film 4, the insulating film 5, and the counter electrode 6 formed on the insulating film 3. When such a step is formed, the thickness of the insulation M3 and the like at that portion becomes extremely thin, which poses a problem in that short circuits and the like are more likely to occur. For this reason, product yield and device reliability have been reduced.

``Object of the Invention'' The purpose of the present invention is to provide an electrode substrate for a display element that solves the problems of the prior art described above and improves reliability by preventing the occurrence of short circuits at the shoulders of transparent electrodes. It is about providing.

"Structure of the Invention" The electrode substrate for a display element of the present invention includes a patterned transparent electrode and an insulating film on the substrate, in which the electrode substrate and the transparent electrode -1- are provided with the insulating film. It is characterized in that the films are stacked with their top surfaces flattened.

In this way, the insulating film is laminated on the substrate and the transparent electrode with the top surface flattened, so there is no step at the shoulder of the transparent electrode, and the transparent electrode is firmly covered by the insulating film, which prevents short circuits. This is prevented and the reliability of the device is improved.

Embodiment of the Invention" FIG. 11 shows an embodiment of a thin film EL display element to which the present invention is applied.

This thin film EL display element includes a glass substrate 11-, a transparent electrode 12-, and a transparent electrode 12-. Insulating film 13, EL light emitting film 14, insulating film 15,
The counter electrodes 16 are sequentially stacked. The transparent electrode 12 is made of an ITO film in which l11203 is doped with 5n02, the insulating films 13 and 15 are made of Ta205, the KL light emitting film is made of a film in which ZnS is doped with Mn,
The counter electrode 16 is made of an AI film. In the present invention, the insulating film 13 covers the substrate 11 and the transparent electrode 12'', and its upper surface is flattened. Therefore, there is no stepped portion of the insulating film 13 at the shoulder portion of the transparent electrode 12, and the EL light emitting film 14, the insulating film 15, and the counter electrode 16 formed on the insulating film 13 are also formed flat.

The transparent electrode 12 and the insulating film 13 can be formed as follows. That is, as shown in FIG. 2, a transparent electrode 12 is formed on a substrate 11 to a thickness of about 1,500 to 2,000 layers. Then, the transparent electrode 12'' and the resist 1
7 (Product name r0FPR-800J, Tokyo Ohka Co., Ltd.)
Coat (manufactured by) to a thickness of 1 to 2 $LI1 and develop into a pattern. As shown in FIG. 3, the portions of the transparent electrode 12 that are not covered with the resist 17 are removed by etching.
The transparent electrode 12 is patterned. As shown in Figure 4,
Targeting Ta, Ar 80SCCM, 0213
An insulating film 13' made of Ta205 is formed by sputtering in an atmosphere of 8CCH at a substrate temperature of 120.degree. C. or lower. In this case, the thickness of the insulating film 13° is the thickness of the transparent electrode 1
The thickness is about the same as 2, that is, 1,500 to 2,000 people. As shown in FIG. 5, the resist 17 is peeled off and the insulating film 13' laminated on the resist 17 is removed by a lift-off method. As a result, the insulating film 13° and the transparent electrode 12 are at the same height, that is, the insulating film 13° is buried in the gap between the transparent electrodes 12. As shown in FIG. 6, the insulating film 1 was sputtered under the same conditions as above.
An insulating film 13 is formed by further laminating Ta205 on the transparent electrode +21- and the transparent electrode +21-. The thickness of the insulating film 13 on the transparent electrode 12'' is approximately 5000 Å or less. In this way, the transparent electrode 12 is completely covered with the insulating film 13,
Moreover, the upper surface of the insulating film 13 is flattened. Note that the insulating film 1
3, Y2O3, 5iJ4.5iOz, SiC, etc. can also be used.

Furthermore, the EL light emitting film 14 on the insulating film 13, the insulating film 15,
The counter electrode 16 can be formed by a conventional method, such as a sputtering method.

In this thin film EL display element, since there is no step difference in the insulating film 13, the transparent electrode 12 is completely covered with the insulating film 13, the occurrence of short circuits is extremely reduced, and reliability is improved.

Note that the present invention can be applied not only to thin film EL display elements but also to electrode substrates such as liquid crystal display elements. However, the present invention is particularly effective for thin film EL display elements in which short circuits often occur at the shoulders of transparent electrodes because the entire layer is formed thin and high voltage is applied.

"Effects of the Invention" As explained above, according to the present invention, since the insulating film is laminated on the substrate and the transparent electrode with the upper surface flattened, there is no step at the shoulder of the transparent electrode. The transparent electrode is tightly covered with the insulating film, preventing the occurrence of short circuits and improving the reliability of the device.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an example in which the present invention is applied to a thin film EL display element, and FIGS. FIG. 7 is a partial cross-sectional view showing an example of a conventional thin film EL display element. In the figure, 11 is a substrate, 12 is a transparent electrode, 13.13° is an insulating film, 14 is an EL light emitting film, 15 is an insulating film, and 18 is a counter electrode.

Claims (1)

[Claims] An electrode substrate for a display element comprising a patterned transparent electrode and an insulating film on a substrate, characterized in that the insulating film is laminated on the substrate and the transparent electrode with the upper surface flattened. An electrode substrate for a display element.