JPH0317192B2 - - Google Patents

Description

[Detailed description of the invention] (1) Technical field of the invention The present invention relates to EL (electroluminescence)
This invention relates to improvements in the manufacturing method of electrode substrates suitable for display panels (referred to as EL).

(2) Background of the technology In recent years, thin-film EL display panels with a so-called double insulating layer structure, in which an EL layer is sandwiched between dielectric layers in a sandwich pattern, have been developed and put into practical use.

(3) Prior Art and Problems The conventional manufacturing method of such an EL display panel will be explained with reference to FIG. First, a predetermined pattern of linear lower electrodes 2 made of transparent indium tin oxide (ITO) are arranged in parallel on a transparent insulating substrate 1 such as glass by vapor deposition and photolithography. Next, a first dielectric film 3 such as yttrium oxide (Y ₂ O ₃ ) is formed on such a lower electrode by vapor deposition. Next, an EL layer 4 made of zinc sulfide (ZnS; Mn) doped with manganese is formed thereon by vapor deposition. Further, a second dielectric film 5 such as Y ₂ O ₃ is formed on this by vapor deposition, and then aluminum (Al) is formed on this.
The upper electrode 6 is formed by vapor deposition and photolithography so as to be arranged perpendicularly to the lower electrode. A light emitting cell is formed at each intersection between the lower electrode 2 and the upper electrode 6, that is, the opposing region,
The light from these light emitting cells is observed from the insulating substrate 1 side.

By the way, each of the dielectric films 3, 5 and the EL layer 4 described above has a very thin thickness of about 5000 Angstroms, and these dielectric films 3, 5, the EL layer 4, and the upper electrode are placed on the patterned lower electrode. An enlarged cross-sectional view of the state in which 6 is formed is shown in FIG. In the figure, 6 is the upper electrode, and between it and the lower electrode 2 are the dielectric films 3, 5 and EL.
It is assumed that layer 4 has been formed. In other words, since the lower electrode is formed linearly in a predetermined pattern, the dielectric films 3, 5 and
The EL layer 4 is formed along the lower electrode 2,
The dielectric films 3 and 5 and the EL layer formed on the edge portion A of the lower electrode are thinner than those formed on the other portions.

EL with such locally thin dielectric film
When a voltage is applied between the upper electrode and the lower electrode of the display panel to operate the panel, an electric field is concentrated at the location where the locally thin dielectric film is formed,
There is a risk that dielectric breakdown will occur in this part and the panel will deteriorate. Further, such problems are not limited to electrodes of EL display panels, but also occur in electrode substrates of other display panels having a multilayer structure such as external electrode type gas discharge display panels.

(4) Purpose of the Invention The present invention eliminates the above-mentioned drawbacks, prevents the formation of a locally thin dielectric layer on the electrode, and provides a highly reliable display panel in which the concentration of electric field is eliminated in those areas. The purpose is to obtain an electrode substrate.

(5) Structure of the Invention A method for manufacturing an electrode substrate according to the present invention to achieve the above object is to form a conductor layer to become an electrode on an insulating substrate, and then apply a photoresist film in a predetermined pattern on the conductor layer. After forming the patterned photoresist film, the conductor layer is etched using the patterned photoresist film as a mask to form an electrode in a predetermined pattern, and then an insulating film is formed on the upper surface of the substrate including the photoresist film surface, and then the photoresist film is etched. By removing the resist film, the insulating film on the resist film is also removed, and the insulating film is buried between the patterned electrodes.

(6) Embodiment of the Invention An embodiment of the present invention will be described in detail below with reference to the drawings. The present invention is shown from Fig. 3 to Fig. 7.
FIG. 8 is a cross-sectional view showing the steps of the manufacturing method when applied to an EL display panel, and FIG. 8 is a cross-sectional view of an EL display panel formed by the method of the present invention.

First, as shown in FIG. 3, a transparent conductor layer 12 made of ITO is formed by vapor deposition on a transparent insulating substrate 11 such as a glass substrate.

After that, a photoresist film is applied on the conductor layer 12, and then the photoresist film is formed into a predetermined pattern by photolithography. Reference numeral 13 in FIG. 4 shows the photoresist film thus formed.

Thereafter, as shown in FIG. 5, using the patterned photoresist film 13 as a mask, the lower conductive layer is etched into a predetermined pattern using hydrochloric acid (HCl) or the like. 12A in FIG. 5 is a lower electrode having a predetermined pattern formed in this way.

Thereafter, as shown in FIG. 6, a silicon dioxide (SiO ₂ ) film 14 is formed on the entire surface of the substrate by vapor deposition, and is buried between the lower electrodes 12A formed by the patterning. The photoresist film 1 is then patterned and formed.
3 is removed using a photoresist film removing agent, and the SiO ₂ film thereon is also removed by a so-called lift-off method. This state is shown in FIG. In this way, the space between the patterned linear lower electrodes 12A is buried with the SiO ₂ insulating film 14, and there is no difference in level between the lower electrode and the substrate.

After preventing a step from occurring between the lower electrode surface and the substrate surface as described above, the first dielectric layer 15 made of Y ₂ O ₃ and the EL layer 16 made of (ZnS; Mn) are placed thereon. Second dielectric layer 1 made of Y ₂ O ₃
7 and an upper electrode layer 18 made of Al are sequentially formed by vapor deposition, and then the upper electrode layer 18 is formed in a predetermined pattern so as to be orthogonal to the lower electrode using photolithography.

In this way, the upper electrode is formed in a flat state, and the dielectric layer is formed thinly at the edge of the lower electrode, such as in an EL display panel formed by the conventional method, causing dielectric breakdown at that part. Such inconveniences will no longer occur.

In the above embodiments, a thin film EL display panel driven by AC voltage was used as an example, but the lower electrode is formed on an insulating substrate, and the EL layer and upper electrode are formed on the lower electrode without a dielectric film. The present invention is also useful for EL display panels driven by direct current voltage, such as those directly formed in the present invention, and can also be applied to electrode substrates such as gas discharge display panels. In addition to SiO ₂ , the lower electrode may be buried with an insulating film such as Y ₂ O ₃ or may be buried so as to protrude higher than the surface of the lower electrode.

(7) Effects of the Invention As described above, according to the method of manufacturing an electrode substrate for a display panel of the present invention, there is no difference in level on the surface of the film laminated on the electrode, so there is an advantage that various highly reliable display panels can be obtained. occurs.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an EL display panel manufactured by the conventional method, Figure 2 is a diagram showing defects in the EL display panel manufactured by the conventional method, and Figures 3 to 7 show the EL display panel of the present invention. FIG. 8, which is a diagram showing the steps of an embodiment of the manufacturing method when applied to a panel, is a cross-sectional view of an EL display panel formed by the method of the present invention. In the figure, 1 and 11 are glass substrates, 12 is an electrode conductor layer, 2 and 12A are lower electrodes, 3, 5,
15, 17 are dielectric layers, 4, 16 are EL layers, 6,
18 is an upper electrode, 13 is a photoresist film, and 14 is an upper electrode.
SiO ₂ layer, A indicates the edge part.

Claims (1)

[Claims] 1 After forming a conductor layer to become an electrode on an insulating substrate, a photoresist film with a predetermined pattern is formed on the conductor layer, and then the conductor layer is etched using the photoresist film to be patterned as a mask to form a predetermined pattern. An electrode is formed, and then an insulating film is formed on the upper surface of the substrate including the photoresist film surface, and then the photoresist film is removed, thereby removing the insulating film on the resist film and forming a gap between the patterned electrodes. A method for manufacturing an electrode substrate for a display panel, characterized in that an insulating film is buried therein.