JPH10144470A - Manufacture of el display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate failure, for instance, thinning, disconnection, etc., of an extraction electrode in etching by deterioration of an electrode layer, so that an EL display can be manufactured with good reproducibility. SOLUTION: An upper/lower part electrode 2, 6 having a plurality of electrodes is provided, an electrode layer covering an end part of a plurality of these electrodes is formed. Prior to forming this electrode layer, between each electrode in a plurality of the electrodes, a sacrifice part 16 crossing with a peripheral part of the electrode layer is left as provided. The electrode layer is laminated on this sacrifice part 16. Thereafter, the electrode layer is applied with patterning by etching, the sacrifice part 16 is removed, also a extraction electrode is formed. The sacrifice part 16 is removed by an etching fluid in the case of applying patterning to the electrode layer. Accordingly, a peripheral part of the electrode layer in an upper part of the sacrifice part 16 is separated therewith (lift off).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for manufacturing an EL display used for a display device.

[0002]

2. Description of the Related Art FIG. 7A is a sectional view of an EL display. As shown in FIG. 7A, an EL display has a glass substrate 1 on which a lower electrode 2 as a data electrode, a first insulating film 3, a light emitting layer 4, a second insulating film 5, and an upper electrode as a scanning electrode. 6 are sequentially stacked. At the tips of the upper electrode 6 and the lower electrode 2, an extraction electrode 70 of Ni or the like is formed.

As shown in FIG. 7B, the extraction electrode 70 has an electrode layer 7 formed so as to cover the tips of a plurality of upper electrodes 6 and lower electrodes 2. It is patterned and formed so as to be divided. At this time, the electrode layer 7 is formed in a high temperature and vacuum state using a predetermined film forming mask.

[0004]

However, when the electrode layer 7 is formed, a small amount of water contained in each film formed before the electrode layer 7 is released at a high temperature and in a vacuum state. As shown in FIG. 8, along the edge of the opening 81 of the film forming mask 8, the outer peripheral portion 7a of the electrode layer 7 is deteriorated by oxidation or the like.

Therefore, the outer peripheral portion 7a of the deteriorated electrode layer 7 is formed.
Cannot be sufficiently removed at the time of etching, and as shown in FIG. 9, an unetched portion (a hatched portion in the drawing) occurs, and a short circuit occurs in the lower electrode 2 and the upper electrode 6. Further, the outer peripheral portion 7a of the altered electrode layer 7 can be completely removed by lengthening the etching time, but the unaltered electrode layer 7 is over-etched, and as shown in FIG. There is a problem that a drawback such as thinning of the extraction electrode 70 or disconnection occurs.

[0006] The present invention has been made in view of the above points,
An object of the present invention is to eliminate defects at the time of etching due to deterioration of the electrode layer 7 and to manufacture an EL display with good reproducibility.

[0007]

The present invention employs the following technical means to achieve the above object. According to the first aspect of the present invention, at least one of the lower electrode (2) and the upper electrode (6) has a plurality of electrodes, and the electrode layer (7) covers the ends of the plurality of electrodes. Is formed, and the electrode layer (7) is patterned to form the extraction electrode (70). In an EL display manufacturing method, an outer peripheral portion (7a) of the electrode layer (7) is provided between each of a plurality of electrodes. An intersecting sacrificial portion (16) is provided, and an electrode layer (7) is laminated on the sacrificial portion (16). And
The electrode layer (7) is patterned by etching to remove the sacrifice portion (16) and form the extraction electrode (70).

Specifically, the electrode layer (7) covers only the end of the lower electrode (2), and
The upper electrode (6) may be formed separately from the one that covers only the end of the upper electrode (6). By the way, the sacrifice part (16)
It is removed by etching when patterning the electrode layer (7). Therefore, the sacrificial portion (16) is changed to the light emitting layer (4).
When the electrode layer (7) is provided so as to intersect with the outer peripheral portion (7a), the sacrifice portion (16) is removed when the electrode layer (7) is patterned, and the electrode on the sacrifice portion (16) is removed. The outer peripheral portion (7a) of the layer (7) is peeled off (lifted off) together with the sacrificial portion (16).

As a result, defects at the time of etching due to deterioration of the electrode layer (7), for example, the extraction electrode (7)
It is possible to eliminate defects such as thinning of 0) or disconnection, and it is possible to manufacture an EL display with good reproducibility. In addition, the size of the sacrificial portion (16) is such that the length (16b) of the upper electrode (6) or the lower electrode (2) in the longitudinal direction is 1 mm or more and the upper electrode (6) or It is sufficient that the length (16a) of the lower electrode (2) in the width direction is 10 μm or more.

In the invention according to claim 4 or 5,
The sacrifice portion (16) is made of the same material as the light emitting layer (4) or the upper electrode (6), and the sacrifice portion (16) is formed by patterning together with the light emitting layer (4) and the upper electrode (6). It is characterized by the following. As described above, if the sacrifice portion (16) is made of the same material as the light emitting layer (4) and the upper electrode (6), and the sacrifice portion (16) is patterned and formed,
Since the number of steps required only to form the sacrificial portion (16) can be reduced, the number of steps can be reduced.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1A shows the EL display after the upper electrode 6 is formed. As shown in the figure, the upper electrode 6 and the lower electrode 2 are formed in an orthogonal stripe pattern, and the distance between the upper electrode 6 and the lower electrode 2 is a distance A, for example, 200 μm or the like. They are formed at intervals of about 100 μm.

The upper electrode 6 or lower electrode 2
A sacrificial film 16 is formed between the electrodes. The sacrificial film 16 is formed in a rectangular shape, and is formed of the same material as the upper electrode 6 at the same time as the upper electrode 6 is patterned. FIG. 1B is an enlarged view of the sacrifice portion 16. As shown in FIG. 1B, the dimensions of the sacrifice portion 16 are determined in the width direction of the electrode in consideration of a dimensional error of the film forming mask, an overlay error between the film forming mask 8 and the glass substrate 1 described later, and the like. Has a length 16a of 10 μm or more,
Further, the length 16b of the electrode in the longitudinal direction is set to 1 mm or more.

Next, steps required until a sacrifice portion 16 shown in FIG. 1A is formed will be described. A lower electrode 2 which is a transparent conductive film such as ITO is formed on a glass substrate 1. Thereafter, a lower insulating layer 3, a light emitting layer 4 made of ZnS, Mn, and the like, and an upper insulating film 5 are patterned and formed on the upper surface by photolithography and etching in this order. Then, a conductive film made of ZnO or the like is formed thereon, and the upper electrode 6 and the sacrificial portion 16 are simultaneously formed by photolithography using the conductive film.
Patterning is formed by etching.

Next, an electrode layer 7 made of Ni or the like is formed on the tips of the lower electrode 2 and the upper electrode 6. Electrode layer 7
The film is formed by a vapor deposition method or a sputtering method. As shown in FIG. 2, the film is formed by using a film forming mask 8 provided with an arbitrary opening 81. It is performed selectively, such as forming a film separately. At this time, as shown in FIG. 3, at least a portion on the light emitting layer 4 side of the outer peripheral portion 71 of the electrode layer 7 is orthogonal to the sacrificial film 16.

The dimensions of the sacrificial portion 16 are as described above, and the length 16a of the electrode in the width direction is formed smaller than the interval A between the electrodes of the upper electrode 6. The reason why the size of the sacrifice portion 16 is made smaller than the interval A is to perform a short-circuit check between the electrodes when the upper electrode 6 is formed. In this case, each electrode of the upper electrode 6 is short-circuited.

Thereafter, photolithographic etching is performed by using a mixed acid containing nitric acid (for example, a mixed acid of nitric acid, water, hydrochloric acid, acetic acid, and phosphoric acid) or a mixed acid containing sulfuric acid as an etchant. Then, as shown in FIG. 4, the extraction electrode 70 is formed by patterning. At this time, etching is performed without leaving a photoresist on the sacrificial portion 16.

Here, when the electrode layer 7 is formed, the outer peripheral portion 7a of the electrode layer 7 is included in each of the films 2, 3, 4, 5, and 6 formed before the electrode layer 7 is formed. It is oxidized by a small amount of water and deteriorates. Therefore, at the time of photolithography etching, the outer peripheral portion 7a of the deteriorated electrode layer 7 cannot be easily etched even with the etching solution.

However, since the sacrifice portion 16 formed of ZnO or the like is easily melted during photolithography etching, the outer peripheral portion 7a of the electrode layer 7 formed perpendicular to the sacrifice portion 16 is peeled off. (Lift off). FIG. 5 is a conceptual diagram showing this peeled state.
As shown in FIG. 5, the outer peripheral portion 7a of the upper electrode layer 7 removed by photolithography etching is peeled off,
As a result, as shown in FIG. 6, the respective electrodes of the outer peripheral portion 7a of the electrode layer 7 are electrically separated.

However, as shown in FIG. 6, since the line width of the sacrifice portion 16 is formed to be slightly smaller than the distance A between the lower electrode 2 and the upper electrode 6, after the etching, the extraction electrode 70 is formed. The outer peripheral portion 7a of the electrode layer 7 slightly protruding from
Will remain, but there is no problem in performance. As described above, the light emitting layer 4 side of the outer peripheral portion 7a of the electrode layer 7 that has been deteriorated by oxidation or the like can be reliably and easily removed, so that the lower electrode 2 and the upper electrode 2 that are generated when the outer peripheral portion 7a cannot be removed are removed. Short-circuiting of the electrode 6 can be prevented, and thinning of the extraction electrode 70 due to over-etching can be prevented.

After that, although not shown, a glass plate is arranged on the upper electrode 6, the glass substrate 1 and the like are cut into a desired shape, and then each of the extraction electrodes 70 is soldered to a predetermined external wiring. The EL display is completed. At this time, the portion of the outer peripheral portion 7a of the electrode layer 7 that has been altered due to oxidation or the like is cut away from the light emitting layer 4, so that there is no problem if it is not removed during photolithography and etching.

In this embodiment, the upper electrode 6
At the same time, the sacrificial portion 16 is formed of ZnO or the like which is a material of the upper electrode 6, and the material of the sacrificial portion 16 is
Any substance may be used as long as it is easily soluble in an etching solution used for patterning the substrate. For example, when the light emitting layer 4 is formed, the sacrificial portion 16 is made of ZnS or the like which is a material of the light emitting layer 4.
Alternatively, only the sacrifice portion 16 may be formed in a separate step without forming the upper electrode 6 and the light emitting layer 4 at the same time.

In this embodiment, the matrix type E
The present invention is applied to an L device. For example, the present invention is applied to a 7-segment EL display in which one of an upper electrode and a lower electrode is a common electrode and the other is a plurality of electrodes. You may.

[Brief description of the drawings]

FIG. 1 is an embodiment of the present invention, wherein (a) is an overall view of an EL display after a sacrifice portion 16 is formed, and (b) is a partially enlarged view of the vicinity of the sacrifice portion 16 in (a). It is.

FIG. 2A is a view showing EL when a film forming mask 8 is arranged.
FIG. 2B is a schematic view of the display, and FIG. 2B is a cross-sectional view of FIG.

FIG. 3 is a schematic diagram showing the vicinity of the tip of an upper electrode 6 or a lower electrode 2 after an electrode layer 7 is formed.

FIG. 4 is an overall view of an EL display after formation of an extraction electrode 70;

FIG. 5 is a schematic diagram of the vicinity of the tip of the upper electrode 6 or the lower electrode 2 during photolithography etching.

FIG. 6 is a schematic diagram of the vicinity of the tip of the upper electrode 6 or the lower electrode 2 after photolithography and etching.

FIG. 7 shows a conventional E after forming an electrode layer 7;
It is a schematic diagram of an L display.

8 is an explanatory diagram when the electrode layer 7 shown in FIG. 7 is formed.

FIG. 9 is a schematic view of the vicinity of the tip of the upper electrode 6 or the lower electrode 2 when the extraction electrode is patterned.

FIG. 10 is a schematic diagram of the vicinity of the tip of the upper electrode 6 or the lower electrode 2 when the etching time is extended in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Lower electrode, 3 ... 1st insulating film, 4 ...
Light emitting layer, 5: second insulating film, 6: upper electrode, 7: electrode layer,
7a: outer peripheral portion, 70: extraction electrode, 16: sacrificial portion, 1
6a: length of the sacrificial portion in the width direction of the electrode, 16b: length of the sacrificial portion in the longitudinal direction of the electrode, A: interval between the electrodes.

Claims (5)

[Claims] 1. A lower electrode (2), a lower insulating layer (3), a light emitting layer (4), an upper insulating layer (5), and an upper electrode (6) are sequentially laminated on a substrate (1). At least one of the electrode (2) and the upper electrode (6) has a plurality of electrodes, and after forming an electrode layer (7) covering the ends of the plurality of electrodes, (7) A method for manufacturing an EL display, comprising patterning (7) and forming an extraction electrode (70) on each of the plurality of electrodes for establishing electrical continuity with the outside. Electrode layer (7)
Providing a sacrificial portion (16) intersecting the outer peripheral portion (7a) of the above, forming an electrode layer (7) on the sacrificial portion (16), and patterning the electrode layer (7) by etching. Removing the sacrificial portion (16) and forming the extraction electrode (70). 2. The electrode layer (7) is formed at a plurality of places separately into a layer that covers only an end of the lower electrode (2) and a layer that covers only an end of the upper electrode (6). The method for manufacturing an EL display according to claim 1, wherein: 3. The size of the sacrificial portion (16) is such that the longitudinal length (16b) of the upper electrode (6) or the lower electrode (2) is 1 mm or more, and the upper electrode (6) or The length (16a) of the lower electrode (2) in the width direction is 10
The method for manufacturing an EL display according to claim 1, wherein the thickness is at least μm. 4. The sacrifice portion (16) is made of the same material as the light emitting layer (4), and the sacrifice portion (16) is formed by patterning together with the light emitting layer (4). 4. The method for manufacturing an EL display according to any one of items 1 to 3. 5. The sacrifice portion (16) is made of the same material as the upper electrode (6), and the sacrifice portion (16) is formed by patterning with the upper electrode (6). 4. The method for manufacturing an EL display according to any one of items 1 to 3.