JPH1115009A - Manufacture of display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesion between a plated layer and a transparent electrode pattern and to provide a display device high in reliability by removing alignment layer soil on the transparent electrode pattern. SOLUTION: A liquid crystal cell 13 is immerged in alkali series cleaning agent, and alignment layer pollutants are cleaned off ITO transparent electrode line 19 in a non-display area 21 of the liquid crystal cell 13. For alkali series cleaning agents, warmed water solution of sodium hydrate is used. The liquid crystal cell 13 is immerged in a liquid containing a catalyst like Pd, etc., to selectively add the catalyst only on the ITO transparent electrode line 19. The liquid crystal 13 is immerged in non-electrolytic plating liquid, and Ni-Pd layer 22 is formed by the non-electrolytic plating on the catalyst-added part of ITO transparent electrode line 19 exposed in the non-display area 21. The adherence between Ni-Pd layer 22 and ITO is enhanced by heating by using an oven. An Au layer 23 is formed on Ni-Pd layer 22 by non-electrolytic plating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a display device in which a transparent electrode layer formed on a glass substrate, an organic film or the like is further covered with a plating layer by electroless plating.

[0002]

2. Description of the Related Art In recent years, a COG (Chip On Glass, chip-on-glass) type liquid crystal display module in which a driving semiconductor element is mounted on a glass substrate has been proposed and has already been put to practical use. According to the liquid crystal module of the COG system, a transparent conductive layer is formed using ITO as a transparent conductive material. However, since the ITO itself has a large resistance value (sheet resistance: 10 to 200 Ω / □), it is driven. It was not possible to secure a sufficient amount of current to drive the semiconductor.

[0003] Therefore, Ni-P is formed on the ITO transparent conductive layer.
There has been proposed a structure in which a metal such as Au is formed on a plating film of Ni-based or Ni-B type or the like and a film obtained by combining them by a vapor deposition method, a sputtering method, an electroless plating method, or the like. (JP-A-3-64869, JP-A-63-255)
377). In addition, among the above film forming methods, there is a tendency to adopt an electroless plating method capable of selectively forming a film and reducing the film forming cost.

In the COG type liquid crystal module, when performing the above electroless plating, (1) a method of plating each glass substrate at a stage before two glass substrates are bonded, or 2) There is a method of plating a liquid crystal cell after bonding two glass substrates, but the latter method (2) tends to be adopted in order to reduce production efficiency and loss of in-process defects.

[0005]

However, when the electroless plating is performed according to the method (2), there is a problem that the adhesion between the transparent conductive layer and the electroless plating is poor. Hereinafter, this problem will be described with reference to FIG. FIG. 2 is an enlarged sectional view of a main part of the liquid crystal display panel 1. Reference numeral 2 denotes a scanning-side glass substrate, and reference numeral 3 denotes a signal-side glass substrate. A liquid crystal material 5 is sealed between the two glass substrates 2 and 3 via a seal portion 4 to form a display area 6. Transparent electrode patterns 7 and 8 are formed on the inner surfaces of the two glass substrates 2 and 3, and an alignment film 9 is formed on the transparent electrode patterns 7 and 8. The metal layer 12 is extended to the non-display area 10 and a metal layer 12 is laminated on the extended transparent electrode pattern 11 by electroless plating.
The metal layer 12 has, for example, a laminated structure of a Ni—P-based layer and an Au layer.

However, according to the liquid crystal display panel 1 having the above structure, the rubbing treatment is performed after the formation of the alignment film in order to align the liquid crystal material to be sealed. However, the transfer of the alignment film and the contamination of the rubbing cloth used for the rubbing treatment are performed. As a result, contaminants adhere to the transparent electrode pattern in the non-display area. As a result, contaminants are present between the transparent electrode pattern and the electroless plating layer even when the electroless plating is performed thereafter, so that the adhesion strength between the transparent electrode pattern and the electroless plating layer is sufficient even when the annealing treatment is performed. In particular, when the contamination state is remarkable, there is a problem that the plating layer peels off from the transparent electrode pattern and bulges or falls off to form a pinhole. Therefore, the present invention has been made in view of the above circumstances. It is completed and aims to improve the adhesion between the plating layer and the transparent electrode pattern by improving the plating method, and to obtain a highly reliable display device.

[0007]

In order to solve the above-mentioned problems, the present invention relates to a method for manufacturing a display device in which a plating layer is formed on a transparent electrode pattern on a liquid crystal cell by using an electroless plating method. A step of bonding one transparent substrate having the pattern formed thereon and the other transparent substrate via a sealing member, injecting liquid crystal, forming a liquid crystal cell, and a step of removing alignment stains on the transparent electrode pattern, The structure includes a step of applying a catalyst, a step of providing a Ni plating layer on the transparent electrode pattern by electroless plating, and a step of providing an upper plating layer on the Ni plating layer by electroless plating.

In the step of removing the alignment stain on the transparent electrode pattern, cleaning is performed using an alkaline cleaning material. In the step of removing the alignment stain on the transparent electrode pattern, cleaning is performed using plasma cleaning. In the step of removing the alignment stain on the transparent electrode pattern, the stain is removed by mechanical polishing.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows a configuration before mounting a semiconductor element for driving a liquid crystal display panel of a COG system, which is called a liquid crystal cell. FIG. 1 is an enlarged sectional view of a main part of the liquid crystal cell 13.

The liquid crystal cell 13 shown in FIG. 1 has a structure in which a glass substrate 14 as one transparent substrate and a glass substrate 15 as the other transparent substrate are bonded to each other with a sealing portion 16. A liquid crystal material L is sealed in the enclosed internal area, and forms a display area 17. Each glass substrate 1
ITO transparent electrodes 18 and 19 (film thickness: 500 to 3) as transparent electrode patterns on the inner surfaces (opposing surfaces) of Nos. 4 and 15 respectively.
000 ° and a sheet resistance of 20Ω / □).
These ITO transparent electrodes 18 and 19 are arranged so as to be orthogonal to each other, an alignment film 20 is formed thereon, and the surface is rubbed to set the direction of the liquid crystal molecules in a predetermined direction.

On the ITO transparent electrode 19 in the non-display area 21 of the glass substrate 15, a Ni plating
A P layer 22 (film thickness: 0.5 to 1.0 μm) and an Au layer 23 (film thickness: 0.2 to 1.5 μm) as an upper plating layer are sequentially laminated. Next, a process of manufacturing the liquid crystal cell 13 will be described in detail. First, an ITO film (thickness 5) is formed on one main surface of the glass substrates 14 and 15 by sputtering or vapor deposition.
Then, a plurality of ITO transparent electrode patterns 18 and 19 are linearly arranged in a square or rectangular display area 17 by photoetching. The ITO transparent electrode 19 extends to a non-display area of the glass substrate 15.

Next, an alignment film 20 is applied and formed on the transparent electrode patterns 18 and 19 in the respective display areas 17 of the glass substrates 14 and 15 and is solidified by heating. Next, the surface of the alignment film 20 is rubbed. Next, the respective glass substrates 14 and 15 are crossed so that the respective ITO transparent electrode lines 18 and 19 intersect.
In addition, the cells are arranged so as to face each other, and then the periphery of the display area 17 is bonded via a seal portion 16 to form an empty cell.

Next, in this empty cell, the display area 17
A liquid crystal material L is injected into the inside to form a liquid crystal cell. Next, the ITO transparent electrode pattern 19 in the non-display area 21 of the liquid crystal cell
The liquid crystal cell was immersed in an alkaline cleaning material in order to remove the alignment stain. Here, a solution obtained by heating an aqueous solution of 10% by weight of sodium hydroxide to 70 ° C. was used as the alkaline cleaning material. Further, at the time of cleaning, by adding rocking or using ultrasonic waves as appropriate, the cleaning effect is enhanced, and the alignment stain can be further removed.

Next, the liquid crystal cell is immersed in a liquid containing a catalyst such as Pd, and the difference in affinity between the glass and ITO causes
A catalyst is selectively applied only on the O transparent electrode line 19. Next, when this liquid crystal cell was immersed in an electroless plating solution containing Ni, only the portion to which the catalyst was applied was electroless Ni
The -P plating layer 21 is formed. Thus, the Ni-P layer 22 is formed by electroless plating on each ITO transparent electrode line 19 exposed in the non-display area 21 on the glass substrates 14 and 15 in the liquid crystal cell. Then, by heating at a temperature of 80 to 200 ° C. for about 1 hour, the adhesion between the Ni—P layer and the ITO is increased. Note that this heat treatment may be performed in a later step after providing the Au layer. Here, since the alignment stain on the ITO transparent electrode line was removed in advance, there was no inclusion between the Ni—P layer and the ITO transparent electrode line, and the effect of improving the adhesion by the heat treatment was enhanced.

Next, an Au layer 23 is provided on the Ni--P layer 22 by electroless plating. However, the Au layer 23 is replaced with Au.
In the case where the plating layer and the thick Au plating layer are sequentially laminated, the replacement Au plating layer has
It is formed by depositing Au by a substitution reaction with the i-P layer 22, and usually has a thickness of 0.1 μm or less. Further, the thick Au plating layer is of a self-catalytic type, and is formed by depositing Au by autocatalysis on the substituted Au plating layer, whereby the thickness can be increased. In addition, the wiring resistance can be reduced.

The liquid crystal display device thus obtained has the following characteristics.
No blisters or pinholes were observed due to insufficient adhesion strength between the TO transparent electrode layer and the plating layer, and the adhesion was significantly improved as compared with the liquid crystal display device in which the alignment stain was not removed. It should be noted that the present invention is not limited to the above embodiment, and various changes and improvements may be made without departing from the scope of the present invention.

For example, instead of the Ni-P layer 22, Ni-B
Layer, Ni-Co-P layer, Ni-Cu-P layer, Ni-Cr
A -P layer, a Ni-Fe-P layer, a Ni-Co-Cr-P layer, or the like may be formed. Also, instead of the Au layer 23, Ag, P
A layer selected from d, Pt, Ph, and Pu may be provided. (Example 2) A liquid crystal cell was formed in the same process as in Example 1 described above, and the alignment stain on the ITO transparent electrode pattern was removed using plasma. The plasma cleaning was performed with He-O2 plasma at 10 W for 1 minute. After that, IT
An electroless Ni-P layer 22 on the O transparent electrode line 18, and
Further, an electroless Au plating layer 23 was formed thereon. The plasma cleaning is not limited to the above-mentioned He-O2 plasma, and the same removal effect can be obtained by using argon plasma or the like.

In the liquid crystal display device thus obtained, no blistering due to insufficient adhesion strength between the ITO transparent electrode layer and the plating layer is observed, and the liquid crystal display device has a higher adhesiveness than the liquid crystal display device in which the alignment stain is not removed. Significantly improved.

[0019]

As described above, according to the present invention, the adhesion between the electroless plating layer and the transparent electrode pattern is improved because the alignment stain on the transparent electrode layer is removed before plating. Therefore, the production yield in electroless plating is improved,
As a result, the manufacturing cost can be reduced, and the mounting reliability of the liquid crystal module using the present liquid crystal panel can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a conventional liquid crystal display device.

[Explanation of symbols]

 17 Display area 18, 19 ITO transparent electrode 21 Non-display area 22 Ni-P layer 23 Au layer

Claims (3)

[Claims] In a method of manufacturing a display device, wherein a plating layer is formed on a transparent electrode pattern of a liquid crystal cell by using an electroless plating method, a step of forming a transparent electrode pattern on a substrate, and forming and orienting an alignment film. A step of forming a liquid crystal cell including a step, a step of removing alignment stains on the transparent electrode pattern, a step of applying a catalyst, and a step of providing a Ni plating layer on the transparent electrode pattern by electroless plating. Providing an upper plating layer on the Ni plating layer by electroless plating. 2. The method according to claim 1, wherein the step of removing the alignment stain on the transparent electrode pattern is a step of cleaning using an alkaline cleaning material. 3. The method according to claim 1, wherein the step of removing the alignment stain on the transparent electrode pattern is a step of cleaning using plasma.