JPH08201831A - Manufacture of liquid crystal display element - Google Patents

Abstract

PURPOSE: To prevent damage to a liquid crystal cell and improve the adhesion of a plating layer. CONSTITUTION: The manufacture of a liquid crystal panel consists of the following steps A through G in sequence: the step A is to provide a display area by forming an ITO transparent electrode 7 on a glass substrate 3, the step B is to provide a display area by forming an ITO transparent electrode 6 on a glass substrate 2 and provide a Ni-P layer 8 by applying electroless plating to a transparent electrode pattern in a non-display area, the step C is to heat the Ni-P layer 8 of the glass substrate 2 at 170-250 deg.C, the step D is to form orientation films in the respective display areas on the glass substrates 2, 3 and give rubbing treatment to the surfaces of the orientation films, the step E is to paste the glass substrates 2, 3 together via sealing member 4 along the periphery of the display area, the step F is to fill liquid crystal material into the display area and the step G is to form an Au layer 9 on the Ni-P layer 8 of the ITO transparent electrode 6 in the non-display area on the glass substrate 2 with electroless plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid crystal display element in which a transparent conductive film formed on a glass substrate, an organic film or the like is further coated with a plating layer by electroless plating.

[0002]

2. Description of the Related Art Recently, a COG (Chip On Glass) type liquid crystal module in which a driving semiconductor element is mounted on a glass substrate has been proposed.
It has already been put to practical use.

According to the COG type liquid crystal module, indium tin oxide (abbreviated as ITO) is used.
Is used as a transparent conductive material to form a transparent electrode or a transparent wiring, but since the resistance value of ITO itself becomes large (sheet resistance: 10 to 200 Ω / □), only the driving semiconductor element is driven. It was not possible to secure a sufficient amount of current.

Therefore, Cr is formed on the ITO transparent conductive layer.
Layer and Al layer, Cr layer or Au layer, or Ni layer or Au layer is formed by a vapor deposition method, a sputtering method, an electroless plating method or the like to reduce the wiring resistance. It is being appreciated. Above all, there is a tendency to adopt an electroless plating method capable of selectively forming a film and reducing the manufacturing cost.

Further, as the plating laminated structure, Ni is used.
A structure in which a noble metal such as Au is formed on a -P-based or Ni-B-based plating film and a combination thereof is also proposed (Japanese Patent Publication No. 3-64869, JP-A-63-63869).
-255377).

In the COG type liquid crystal module, when the above electroless plating method is carried out, (1) a method of plating each glass substrate (wafer) before the bonding of two glass substrates, Alternatively, there is (2) a method of plating after bonding two glass substrates (liquid crystal cell), but the latter method (2) is preferable in order to reduce production efficiency and in-process defect loss.

In order to improve the adhesion of the plating layer, 170 to 70% by any of the methods (1) and (2)
It is necessary to perform high-temperature heat treatment up to 250 ° C. That is, in the case of the plating laminated structure proposed by Japanese Patent Publication No. 3-64869, pretreatment, catalyst addition, Ni
The plating is performed by passing through the steps of plating and Au plating, and the ITO of the plating layer is transparent by heating at 170 to 250 ° C. in an oven or the like between the Ni plating step and the Au plating step. Adhesion to the conductive layer can be improved.

[0008]

However, the above-mentioned plating method has a problem that the liquid crystal cell is damaged at a heating temperature of 170 to 250 ° C.

Therefore, an object of the present invention is to eliminate damage caused by heat treatment for improving the adhesion of the plating layer,
Accordingly, it is to provide a method of manufacturing a liquid crystal display device having high performance and high reliability.

[0010]

A method of manufacturing a liquid crystal display device according to the present invention is characterized by including the following steps A to G. Step A: A transparent electrode pattern is formed on one transparent substrate to provide a square or rectangular display area. Step B: A square or rectangular display region is provided by forming a transparent electrode pattern on the other transparent substrate, and a first plating layer is provided by electroless plating on the transparent electrode pattern in the non-display region. Step C: The first plated layer on the other transparent substrate is heated at a temperature of 170 to 250 ° C. Step D: An alignment film is formed on each display area of the one transparent substrate and the other transparent substrate, and the surface of the alignment film is rubbed. Step E: The one transparent substrate and the other transparent substrate are attached to each other via a sealing member made of an adhesive resin arranged along the periphery of the display area. Step F: A liquid crystal material is injected into the display area between the two transparent substrates. Step G: A second plating layer is formed by electroless plating on the first plating layer on the transparent electrode pattern in the non-display area of the other transparent substrate.

[0011]

The present invention will be described in detail below by taking a COG type liquid crystal module as an example. 1 and 2 show this COG
This is a configuration before mounting a driving semiconductor element of a system liquid crystal module, which is generally referred to as a liquid crystal cell. FIG. 1 is a front view of the liquid crystal cell 1, and FIG. 2 is a sectional view taken along the section line XX shown in FIG.

The liquid crystal cell 1 has a structure in which two glass substrates 2 and 3 made of soda lime glass are bonded together by a seal portion 4, and liquid crystal is sealed in an inner region surrounded by the seal portion 4. It forms the display area 5. The ITO transparent electrodes 6 and 7 are formed on the inner main surfaces of the glass substrates 2 and 3, respectively.
(Sheet resistance: 10Ω / □) are arranged. The ITO transparent electrodes 6 and 7 are arranged so as to be orthogonal to each other, an alignment film (not shown) is formed on the ITO transparent electrodes 6, and the surface of the alignment film is subjected to a rubbing treatment so that the liquid crystal molecules are oriented in a predetermined direction. Set to.

Further, FIG. 3 shows a plating layer laminated on the non-display area on the glass substrate 3, 8 is a Ni-P layer which is a first plating layer, and 9 is a second plating layer. It is an Au layer.

Next, the process of producing the liquid crystal cell 1 having the above-mentioned structure will be described in detail. Glass substrate 3 (scanning side electrode substrate) in step A
2, the steps B and C relate to the glass substrate 2 (signal side electrode substrate). The order of the steps B to C and the step A may be exchanged.

Step A: On the glass substrate 3, an ITO film (thickness 500 to 3,000Å) is formed on one main surface by sputtering or vapor deposition, and a plurality of ITO are formed in the square or rectangular display region 5 by photoetching.
The transparent electrodes 7 are arranged in a line. Although not shown, a silver paste for conducting the ITO transparent electrode 7 of the glass substrate 3 on the glass substrate 2 is applied.

Step B: An ITO film (thickness 500 to 3, is formed on one main surface of the glass substrate 2 by sputtering or vapor deposition.
000Å) is formed. Next, a plurality of ITO transparent electrodes 6 are linearly arranged in the display area 5 by photoetching, and the ITO transparent electrodes 6 are extended to the non-display area of the glass substrate 2. After that, a Ni-P layer (thickness: 0.3 to 1.0 μm) is provided by electroless plating over the entire ITO transparent electrode 6, and then the Ni-P layer on the display region 5 is removed by etching.

Step C: The Ni-P layer 8 on the glass substrate 2 is heated in an oven at a temperature of 170 to 250 ° C. for about 1 hour.

Step D: each display area 5 on the glass substrates 2 and 3
An alignment film (not shown) is formed on the top, and the surface of this alignment film is rubbed. Since the baking is performed after applying the alignment film, this baking may be combined with the oven heating in the step C.

Step E: The glass substrates 2 and 3 are arranged so that the ITO transparent electrode lines 6 and 7 intersect and face each other, and then the periphery of the display area 5 is sealed with a seal portion 4. .

Step F: A liquid crystal material is injected into the display area 5. Then, after this step, a lighting inspection can be performed to remove defective products.

Step G: An Au layer 9 is formed on the Ni-P layer 8 on the glass substrate 2 by electroless plating. In particular,
When the Au layer 9 (thickness 0.2 to 1.5 μm) is formed on the Ni—P layer 8 by electroless plating, the Au layer 9 is formed by sequentially stacking a substitution Au plating layer and a thick Au plating layer. Is. The substitution Au plating layer has a Ni-
It is formed by the precipitation of Au by the substitution reaction with the P layer 8 and usually has a film thickness of 0.1 μm or less.
In addition, the thick Au plating layer is an autocatalytic type,
It is formed by depositing Au on the substitutional Au plating layer by an autocatalytic action, whereby the film thickness can be increased and the wiring resistance can be reduced.

After that, a driving semiconductor element is mounted on the glass substrate 2, and the terminal of the driving semiconductor element is connected to the above A.
Wire bonding is performed with the electrode portion of the u layer 9. Thus,
A COG type liquid crystal module could be manufactured by the above series of steps.

The present invention is not limited to the above embodiments, and various modifications and improvements may be made without departing from the scope of the present invention. For example, according to the process B of the above-described embodiment, the ITO transparent electrodes 6 are arranged in a line on the glass substrate 2 by etching, and then the ITO transparent electrodes 6 are formed.
A Ni-P layer was provided on the entire transparent electrode 6, and then the Ni-P layer on the display region 5 was removed by etching. In addition, an ITO layer and a Ni-P layer were formed on the entire surface of the glass substrate 2. After that, patterning may be performed by etching.

Alternatively, according to the above-mentioned embodiment, the Ni-P layer is formed as the first plating layer and the Au layer is formed as the second plating layer, but in addition to that, the Ni-P layer is formed as the first plating layer.
B layer, Ni-Co-P layer, Ni-Cu-P layer, Ni-C
The r-P layer, the Ni-Fe-P layer, the Ni-Co-Cr-P layer, etc. are used as the second plating layer for Ag, Pd, Pt, Rh,
Ru or the like may be formed.

[0025]

As described above, according to the present invention, in the step B, a transparent electrode pattern is formed on the other transparent substrate to provide a square or rectangular display region, and a non-display region is transparent. A first plating layer is provided on the electrode pattern by electroless plating, and then in step C, 170 to 2 is applied to the first plating layer on the other transparent substrate.
By heating at a temperature of 50 ° C., the adhesion of the plating layer to the transparent electrode pattern can be increased,
This eliminates damage to the liquid crystal cell due to the heat treatment, and as a result, a high-performance and highly reliable liquid crystal display element can be provided.

In addition, when the liquid crystal cell can be plated, it suffices to plate only the non-defective product as compared with the method of plating on the glass substrate before assembling the liquid crystal cell, resulting in in-process defect loss. It is suppressed, and thereby, the manufacturing efficiency is increased and the manufacturing cost can be reduced.

Moreover, in the case where a driving semiconductor element is mounted on a glass substrate and wire bonding is performed as in a COG type liquid crystal module, this wire bonding is sufficiently performed and, for example, 1.5 μm.
By forming the Au plating layer having a thickness of m, the sheet resistance can be lowered to 0.03 to 0.02 Ω / □, and the wiring resistance can be remarkably reduced.

[Brief description of drawings]

FIG. 1 is a front view of a liquid crystal cell of an example.

2 is a cross-sectional view taken along a section line XX in the liquid crystal cell of FIG.

FIG. 3 is an enlarged view of a main part of the liquid crystal cell of the example.

[Explanation of symbols]

 1 Liquid crystal cell 2, 3 Glass substrate 6, 7 ITO transparent electrode 8 Ni-P layer 9 Au layer

Claims (1)

[Claims] 1. A method for manufacturing a liquid crystal display device, which includes the following steps A to G: Step A: A transparent electrode pattern is formed on one transparent substrate to provide a square or rectangular display area. Step B: A square or rectangular display region is provided by forming a transparent electrode pattern on the other transparent substrate, and a first plating layer is provided by electroless plating on the transparent electrode pattern in the non-display region. Step C: The first plated layer on the other transparent substrate is heated at a temperature of 170 to 250 ° C. Step D: An alignment film is formed on each display area of the one transparent substrate and the other transparent substrate, and the surface of the alignment film is rubbed. Step E: The one transparent substrate and the other transparent substrate are attached to each other via a sealing member made of an adhesive resin arranged along the periphery of the display area. Step F: A liquid crystal material is injected into the display area between the two transparent substrates. Step G: A second plating layer is formed by electroless plating on the first plating layer on the transparent electrode pattern in the non-display area of the other transparent substrate.