JPS61176011A - Formation of transparent electrode - 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 Field of Industrial Application This invention relates to a method for forming transparent electrodes, and in particular to a method for forming transparent electrodes.
Conventional technology used to form a large number of striped transparent electrodes in Matri-Fuchs panels Conventionally, for AC-operated thin film KL elements, a high electric field (about 10@v/ctn) is regularly applied to the light-emitting layer. In order to improve the dielectric strength, luminous efficiency, and operation stability, etc.,
．． 1-1. MTI (or Cu, 11
A three-layer structure ZnS:Mn (or Zn5e:
, Mn)KL elements have been developed, and improvements in light emitting characteristics have been confirmed. This thin-film KL element emits high-intensity light upon application of an alternating current electric field of 1 kHz, and is characterized by long life.

FIG. 3 shows the basic structure of a ZnS:Mn thin film KL element as an example of a thin film KL element.

To specifically explain the structure of the thin film FiL element based on FIG. 3, In,
A transparent electrode 2 made of O,,SnO, etc. is further laminated on top of the transparent electrode 2 of Y,08,T' z O8%A t! O@, S 1s
A first dielectric layer 3 made of N4, SiOx, or the like is formed by a sublayer, a lid, an electron beam evaporation method, or the like. A ZnS light-emitting layer 4 is formed on the first dielectric layer a by electron beam evaporation of a ZnS:Mn sintered bottom. At this time, a ZnS:Mn sintered pellet for vapor deposition is used, in which the concentration of Mn, which is an active substance, is set to a concentration depending on the purpose.

A second dielectric layer 5 made of the same material as the first dielectric layer 3 is laminated on the ZnS light emitting layer 4, and an At
A back electrode 6 is formed by vapor deposition. The transparent electrode 2 and the back electrode 6 are each formed into a stripe shape as shown in FIG. 4, and a plurality of them are arranged perpendicularly to each other. J..., a cross electrode structure is adopted,
A position 7 (hatched area in the figure) where the transparent electrode 2 and the back electrode 6 intersect in plan view corresponds to one pixel of the panel. The transparent electrode 2 and the back electrode 6 are connected to an AC power source 10 via a switch 8.9, respectively, and the thin film EL element is driven.

In the above configuration, the sui, sochi 8.9 are closed and the electrode 2
．． When an AC voltage is applied between the dielectric layers 2 and 5 on both sides of the ZnS light emitting layer 4, the AC voltage is induced between the dielectric layers 2 and 5 on both sides of the ZnS light emitting layer 4, and the electric field generated within the ZnS light emitting layer 4 excites the conductor. The electrons that have been accelerated and obtained sufficient energy directly excite the Mn luminescent center, and when the excited Mn luminescent center returns to the ground state, it emits orange-yellow light. That is, when the electrons accelerated by a high electric field excite the electrons of the Mn atoms that have entered the zn site, which is the luminescence center in the Zn8 light emitting layer 4, and fall to the ground state, approximately 5850
It emits strong light in a wide wavelength range with peak A.

The thin film PL element having the above structure can be used as a flat thin display device that takes advantage of the Nubase factor to display characters, symbols, still images, moving images, etc. It is very effective and can be used as a display means.

The dielectric layer of the above-mentioned thin-film KL element contains many pinholes, micro-holes, and scratches generated during the manufacturing process, and moisture, etc. enters the ZnS light-emitting layer 4 through these defects, resulting in heat generation due to KL emission loss, This may lead to delamination, deterioration of device characteristics, etc.

In order to solve the above problem, a thin film KL spring /&11 shown in FIG. 5 has been proposed.

This thin film] 1mL Spring/I/11 will be explained based on FIG. Note that the left half of FIG.
A cross-sectional view in the direction is shown, and the right half is in the Y direction perpendicular to the transparent electrode 2.
A cross-sectional view of the direction is shown. 1 is a glass substrate, on which transparent electrodes 2 are arranged parallel to each other in a striped manner with a constant pitch spacing, and on top of which a first dielectric layer 81 is disposed.
Luminous layer 4. Second dielectric layer5. A thin film KL element 12 is constructed in which a back electrode 6 is laminated. A dish-shaped cover glass 13 is superimposed on the glass substrate 1 to accommodate the thin film KL element 12, and the thin film EI and the element 1 are placed in the internal gap.
2 is built-in. The joint between the glass substrate 1 and the cover glass 13 is sealed with an adhesive 14 such as epoxy resin or photocurable resin (Photobond).

That is, the glass substrate 1 and the cover glass 13 constitute an envelope 15 for the thin film EL element 12. and envelope 15
A thin film FiL element 12 is built inside, and an insulating protective fluid 16 for protecting the thin film KL element 12, such as silicone oil or vacuum grease, is filled and sealed (@Kaisho 54).
-12290 Publication).

The transparent electrode 2 in the thin film KL element 12 is
After forming 0, patterning is performed by photolithography using a 7 photoresist film 21. but,
According to such a method, with 20 steps of transparent electrodes,
A first dielectric layer 31 and a light emitting layer 4 formed thereon. The shoulder portion of the second dielectric layer 5 becomes thinner and dielectric breakdown is more likely to occur.

This tendency is similar to the thin film EL matrix 1. In order to prevent an increase in resistance due to an increase in the length of the transparent electrode 2 due to the increase in the size of the panel, the thicker the transparent electrode 2 becomes, the more noticeable this becomes.

Therefore, as shown in FIG. 7, between the transparent electrodes 2°2,
It has been considered to arrange and form an insulating film 19 having approximately the same thickness as this transparent electrode 2 (Utility Model Application No. 58-166670
Publication No.). According to such a configuration, the above-mentioned problem of dielectric breakdown caused by the difference in level of the transparent electrode 20 does not occur.

However, as long as the method shown in FIG. 6 is adopted, the problem remains that the cross-sectional shoulder 2a of the transparent electrode 2 becomes sharp, and the electric field is concentrated on this shoulder 2a, which tends to cause dielectric breakdown.

Means for Solving the Problems Therefore, the present invention forms an insulating film on the entire surface of the glass substrate or does not form it, and patterns the insulating film or the glass substrate with a ring waffle to form parallel patterns at predetermined edges. A large number of striped insulating films or glass protrusions are formed, and a photoresist film is left on the striped insulating films or glass protrusions. A transparent conductive film of the same thickness is formed, and the photoresist film on the insulating film or the glass protrusion is lifted off together with the transparent conductive film thereon to form a striped transparent electrode between the insulating film or the glass protrusion. It is characterized by forming.

Effect According to the above means, since there is an insulating film or a glass protrusion of approximately the same thickness between the transparent electrodes, there is no step difference.
When forming the light emitting layer of the first dielectric layer 1, the second dielectric layer, the back electrode, etc., no steps or thin parts are formed;
The insulating film or glass substrate is patterned first, and then a transparent conductive film is formed while leaving the photoresist film on the insulating film or glass protrusions, so there is no significant step difference between the photoresist film and the glass substrate. When the transparent conductive film becomes large and breaks at the base of the insulating film or glass protrusion, the transparent conductive film can be easily patterned by lift-off to form a transparent electrode, and the shoulders of the transparent electrode are rounded. , so no dielectric breakdown occurs due to electric field concentration on this shoulder.

EXAMPLE Hereinafter, a method for forming a transparent electrode according to an example of the present invention will be explained with reference to the drawings.

FIGS. 1A to 1D show enlarged cross-sectional views of essential parts at each stage of the first embodiment. First, Y is applied to the entire surface of the glass substrate 1.
, ○3, etc. are used as transparent electrodes (
2), the insulating film 20 is formed by vapor deposition or by covering with a lid to a thickness 1, for example, about several thousand λ (FIG. 1A).

Next, by well-known photolithography, a parallel and striped photoresist film 21 is formed at a predetermined pitch and edge on the insulating film 20, and striped window holes are formed in the portion where the transparent electrode (2) is to be formed. 21a is formed, and the insulating film 20 exposed from the window hole 21a is cut and bordered to form a striped insulating film 2''.

(Figure 1B).

Next, a photoresist 1 is applied on the striped insulating film 2o.
The photoresist film 21 is removed while leaving the llf[21]
IF5 on the entire surface from above. A transparent conductive film 22 having a thickness of about several 100X is formed by vapor depositing or sputtering O, SnO, SnO, or the like. At this time, since the difference in level between the top surface of the photoresist film 21 and the top surface of the glass substrate 1 is large, the transparent conductive film 22 is broken at the base of the insulating film 20 (FIG. 1C).

After this, the whole was immersed in an organic solvent and the photorested pattern 2
1 is swollen and dissolved and removed together with the transparent conductive film 22 thereon, thereby forming the transparent electrode 2 between the insulating films 20 and 20. This transparent electrode 2 has approximately the same thickness as the insulating film 20,
Unlike the conventional method, there is no difference in level (Fig. 1D).

Therefore, on the transparent electrode 2, the first dielectric layer 8, the light emitting layer 4. When forming the second dielectric layer 5, no breakage or thinning occurs. Moreover, as is clear from FIG. 1(D), the shoulder portion 2a of the transparent electrode 2 has a rounded shape.
The electric field is not concentrated on the shoulder portion 2a.

FIGS. 2(A) to 2D) show enlarged cross-sectional views of essential parts at each stage of the second embodiment. In this embodiment, a photoresist film 21 is directly formed on the upper surface of the glass substrate 1 without forming an insulating film 20, and the glass substrate 1 is etched to form grooves 2.
3, a glass protrusion 24 is formed between the grooves 28 and 28, and the transparent electrode 2 is formed in the same manner as in the first embodiment. It operates in the same manner as the insulating film 20, and the same effects as in the first embodiment can be obtained.

Effects of the Invention According to the present invention, a transparent conductive film can be patterned using the photoresist film used when patterning an insulating film or a glass protrusion, and transparent electrode patterning is easy without requiring special materials or processes. It can be implemented. Moreover,
Since the insulating film or the glass protrusion having substantially the same thickness is arranged between the transparent electrodes, no breakage or thinning occurs during film formation on the transparent electrodes, and uniform film formation is possible. Furthermore, since the shoulders of the transparent electrodes are rounded, there is no electric field concentration on the shoulders, and thin film EL matrices with high dielectric breakdown strength can be used.
You will get a sox panel.

[Brief explanation of drawings]

Figures 1 (A) to CD) and Figures 2 (A) to D) are enlarged cross-sectional views of main parts at different stages for explaining methods for forming transparent electrodes according to different embodiments of the present invention, respectively. . Figure 3 shows thin film FBI, Ma) IJ Fuchsnell's thin film E
4 is a schematic plan view of the main part of FIG. 3, and FIG. 5 is a sectional view of a thin film KL matrix sox panel using the thin film EL element of FIG. 3. FIG. 6 is an enlarged sectional view of a main part of each step of the conventional method for forming a transparent electrode. FIG. 7 is an enlarged sectional view of a main part of a glass substrate with electrodes for explaining the present invention in detail. 1・・・・・・・・・・・・・・・Glass substrate,
2・・・・・・・・・・・・・・・Transparent electrode, 2
0......Insulating film, 21...
...Photoresist film, 22...
...Transparent conductive film, 24...Glass protrusion. Patent applicant Kansai NEC Corporation Figure 1 Figure 2 FM 2] Figure 6

Claims (1)

[Scope of Claims] (a) A step of forming an insulating film on a glass substrate or not; (b) patterning the insulating film or the upper surface of the glass substrate by photolithography to form a large number of parallel stripes at a predetermined pitch. (c) forming an insulating film or glass protrusion from above the photoresist film while leaving the photoresist film on the stripe-shaped insulating film or glass protrusion; (d) Lifting off the photoresist film on the insulating film or the glass protrusion together with the transparent conductive film thereon to form a transparent conductive film having approximately the same thickness as the insulating film or the glass protrusion; 1. A method for forming a transparent electrode, comprising: forming a striped transparent electrode.