JPS58218792A - Method of producing thin film el element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing a thin film EL device, and particularly to a method for manufacturing a thin film EL device.
The present invention relates to a manufacturing method for preventing dielectric breakdown caused by pinholes in an insulating layer interposed between a lower electrode and a light emitting layer of a jiEL element.

(bl) Conventional technology and problems Thin film EL devices are made of a transparent insulating substrate, a lower transparent electrode, a
an insulating layer made of ZnS:Mn, and a light emitting layer made of ZnS:Mn.

It has a structure in which a second insulating layer and an upper electrode are sequentially laminated.

The first insulating layer inside the EL element having such a structure is E
During operation of the L element, it is exposed to a high electric field of, for example, 10 (V/cm), so if there is a defect such as a pin pole, dielectric breakdown is likely to occur at that part.

In other words, in an element with such a defect, dielectric breakdown occurs at the pinhole part due to the high electric field formed when a driving voltage is applied, and the film quality in that part deteriorates due to Joule heat, which causes further breakdown. As a result, the damage is further expanded, resulting in pixel chipping and electrode disconnection.

Therefore, in order to improve the reliability of EL elements, it is necessary to prevent the occurrence of pinholes, etc. However, such defects occur stochastically in the thin film forming process4, so it is necessary to eliminate them completely. It is extremely difficult to do so.

(C) Purpose of the Invention In view of the above circumstances, the purpose of the present invention is to provide a thin film EL that does not easily cause dielectric breakdown even if a pinhole occurs in the first insulating layer.
An object of the present invention is to provide a method for manufacturing an element.

(d) Structure of the Invention The feature of the present invention is that a sample to be processed, which has a lower electrode and a first insulating layer formed thereon on an insulating substrate, can be treated without reacting with the first insulating layer. A portion of the transparent electrode directly below the pinhole is removed by immersing it in an etching solution that reacts with the lower electrode, and then a light emitting layer is formed on the first insulating layer and a second insulating layer is formed thereon. There is a particular thing.

(el) Embodiment of the Invention An embodiment of the invention will now be described in the order of its manufacturing process with reference to FIGS. 1 to 3.

In the figure, ■ is a glass substrate, and 2 is In and O.

The first lower transparent electrode is made of / S n O@ and has a thickness of approximately 2000 mm, and is formed by depositing Y and 0.0 by sputtering to a thickness of approximately 3000 mm. This is an insulating layer.As described above, pinholes 41 are generated stochastically in this first insulating layer 3.

As mentioned above, if this pinhole 4 is left as it is, various problems will occur. Therefore, in order to prevent this, an etching solution that etches the underlying transparent electrode 2 but does not react with the first insulating layer N3 above it, for example, approximately 45%
C) The substrate is immersed in a hydrochloric acid (HCl) solution heated to .

Then, as shown in FIG. 2, the etching solution seeps into the pinhole 4, removing the portion of the transparent electrode 2 directly below the pinhole 4, and forming a gap 5.

During this step, the first insulating layer 3 does not react with the etching solution, so the pinhole 4 does not enlarge. Note that when carrying out this step, exposed parts such as the ends of the transparent electrode 2 are covered with a resist film 6 to protect them from being removed by the etching solution.

After this, you can proceed according to the normal process. That is, after removing the resist film 6, a light-emitting layer 7 made of ZnS:Mn is coated with Y, 0. A second insulating layer 8 (thickness is, for example, approximately 2000 (people))
, an upper electrode 9 made of aluminum (/l) is formed. Thus, in FIG. 3, a thin film EL as shown in i
A completed device is obtained.

In the thin film EL device according to this example obtained as described above, the portion directly below the pinhole 4 is a gap 5, and the corresponding transparent electrode 2 is not present. Therefore, even when a driving voltage is applied, current does not flow through the pinhole 4 as in an element with a conventional structure, and dielectric breakdown is less likely to occur.

In the above embodiment, the first insulating layer 3 is y, o.

However, the material of the first insulating layer 3 is not limited to this, for example, alumina (Aj!, O,
), silicon nitride<sisN4), tantalum oxide (T a -Os), etc. can also be used.

In short, the first insulating layer 3 may be formed of an insulating material from which an etching solution capable of selectively etching only the transparent electrode 2 can be obtained.

(f) Detailed Description of the Invention According to the present invention, a thin film EL device with less risk of dielectric breakdown can be obtained, and the reliability of the thin film EL device can be improved.

[Brief explanation of the drawing]

FIGS. 1 to 3 are sectional views of essential parts of an embodiment of the present invention showing the manufacturing steps thereof in order. In the figure, ■ is a glass substrate, 2 is a lower transparent electrode, 3 is a first insulating layer, 4 is a pinhole, 5 is a void, 6 is a resist film, 7 is a light emitting layer, 8 is a second insulating layer, 9 is the upper electrode,
shows.

Claims (1)

[Claims] A process of immersing a sample to be processed having a lower electrode and a first insulating layer formed thereon on an insulating substrate in an etching solution that does not react with the first insulating layer but reacts with the lower electrode. A method for manufacturing a thin film EL device, characterized in that, after that, a light emitting layer is formed on the first insulating layer and a second insulating layer is formed on the light emitting layer.