JPH08320501A - Production of liquid crystal display panel - Google Patents

Abstract

PURPOSE: To reduce a manufacturing cost by improve the production yield in electroless plating. CONSTITUTION: This process for producing a liquid crystal panel consists successively of a stage A to a stage G. The stage A: Glass substrates 13, 14 are provided thereon with display regions by forming transparent electrode patterns 17, 18 and the non-display regions of the glass substrate 13 are provided thereon with Ni-P layers 20 by electroless plating. The stage B: Insulating films 22 are formed on a part of Ni-players 20 of the non-display regions 19 of the glass substrate 13. The stage C: The oriented films 22 are formed on the display regions of the glass substrate 13. The stage D: The oriented films existing on the respective display regions of the glass substrates 13, 14 are subjected to rubbing treatments. The stage E: The glass substrate 13 and the glass substrate 14 are stuck to each other via sealing parts 15 along the circumferences of the display regions to form an empty cell. The stage F: A liquid crystal material is injected into the display regions of the empty cell to form a liquid crystal cell. The stage G: Au layers 21 are formed by electroless plating on the Ni-P layers 20 exposed in the non-display regions of the glass substrate 13. The stage H: A semiconductor element for driving is mounted.

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 panel in which a transparent conductive layer 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 (IT for short)
(Referred to as O) is used as a transparent conductive material to form a transparent conductive layer. However, since the resistance value of ITO itself becomes large (sheet resistance: 10 to 200 Ω / □), a driving semiconductor element is driven. It was not possible to secure a sufficient amount of current to make it work.

Therefore, Ni-P is formed on the ITO transparent conductive layer.
A structure has been proposed in which a precious metal such as Au is formed by a vapor deposition method, a sputtering method, an electroless plating method, or the like on a plated film of Ni-based or Ni-B-based and a combination thereof, thereby reducing wiring resistance. (Japanese Patent Publication No. 3-64869, Japanese Patent Laid-Open No. 63-2553).
77). Among the above film forming methods, there is a tendency to adopt an electroless plating method which can selectively form a film and can reduce the manufacturing cost.

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

[0005]

However, when electroless plating is performed according to the method (2), there is a problem that a bridge short circuit occurs. Hereinafter, this problem will be described with reference to FIG.

A and B in FIG. 1 are liquid crystal display panels 1 respectively.
FIG. 3 is an enlarged sectional view of an essential part and an enlarged plan view of an essential part. Reference numeral 2 is a scanning side glass substrate, 3 is a signal side glass substrate, and a liquid crystal material 5 is sealed between both glass substrates 2 and 3 via a seal portion 4 to form a display area 6. Also, both glass substrates 2,
3, transparent electrode patterns 7 and 8 are formed on the inner surfaces of the transparent electrode pattern 3, the transparent electrode pattern 8 is extended to the non-display region 9 of the signal side glass substrate 3, and the extended transparent electrode pattern 10 is electrolessly electrolyzed. The metal layer 11 is laminated by plating. Metal layer 1
Reference numeral 1 is, 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 configuration, the scanning side glass substrate 2 and the signal side glass substrate 3 are provided.
The plating solution invades and stays in the gap s between and, colloidal Au is generated between the metal layers 11 as shown in FIG.
After that, by drying this, a metal layer 11a made of powdered Au is formed, and each metal layer 11 is connected by the metal layer 11a, which causes so-called bridge short circuit. There is.

In order to solve the above problems, a masking technique has been proposed in which a resin or a resist is applied to the gap s to prevent the plating solution from entering. According to this masking technique, the applying process and its There is a problem that the manufacturing cost is increased due to the addition of a resin removing step and the increase in equipment.

Therefore, the present invention has been completed in view of the above circumstances, and an object thereof is to use electroless plating without using a masking technique for applying a resin or a resist to a liquid crystal cell without causing a bridge short. To improve the manufacturing yield and thereby reduce the manufacturing cost.

[0010]

A method of manufacturing a liquid crystal display panel according to the present invention is characterized by comprising the following steps A to H in sequence. Step A: A transparent electrode pattern is formed on one transparent substrate and the other transparent substrate to provide a square or rectangular display region, and electroless plating is performed on the transparent electrode pattern in the non-display region of one transparent substrate. To provide a Ni plating layer. Step B: An insulating film is formed on a part of the Ni plating layer in the non-display area of one transparent substrate. Step C: Alignment films are formed on the transparent electrode pattern in the display area of one transparent substrate and on the transparent electrode pattern in the display area of the other transparent substrate. Step D: The surface of the alignment film on each display region of the one transparent substrate and the other transparent substrate is rubbed. Step E: One transparent substrate and the other transparent substrate are bonded together via a sealing member made of an adhesive resin arranged along the periphery of the display area to form an empty cell. Step F: A liquid crystal material is injected into a display region between two transparent substrates in an empty cell to form a liquid crystal cell. Step G: An upper plating layer selected from Au, Ag, Pd, Pt, Ph and Pu is provided by electroless plating on the Ni plating layer exposed in the non-display area on one transparent substrate in the liquid crystal cell. Step H: A driving semiconductor element is mounted on the upper plating layer of one transparent substrate, and the terminals of the driving semiconductor element and the upper plating layer are electrically connected.

[0011]

The present invention will be described in detail below with reference to FIGS.
FIG. 1 and FIG. 2 show a configuration before mounting a driving semiconductor element of a COG type liquid crystal display panel, which is called a liquid crystal cell. FIG. 1 is a front view of the liquid crystal cell 12, and FIG. 2 is a cross-sectional view taken along the section line XX shown in FIG. FIG. 3 is an enlarged cross-sectional view of the main part of the liquid crystal cell 12.

First, according to the liquid crystal cell 12 shown in FIGS. 1 and 2,
(Signal side) glass substrate 13 as the one transparent substrate
And the (scanning side) glass substrate 1 as the other transparent substrate
4 and the seal portion 15 are attached to each other,
The liquid crystal material L is provided in the inner area surrounded by the seal portion 15.
Are enclosed and form the display area 16. Each glass substrate 13,
The ITO transparent electrodes 17 and 18 (film thickness: 500 to 3000) serving as the transparent electrode pattern on the inner main surface of each of the fourteen.
Å, Sheet resistance: 10Ω / □) are arranged. The ITO transparent electrodes 17 and 18 are arranged so as to be orthogonal to each other, an alignment film (not shown) is formed on the ITO transparent electrodes 17, and the surface of the alignment film is rubbed to direct the liquid crystal molecules in a predetermined direction. Set to.

Further, according to FIG. 3, on the ITO transparent electrode 17 in the non-display area 19 of the glass substrate 13, the Ni-P layer 20 (film thickness: 0.5 to 1.0 μm) as the Ni plating layer is formed.
m) and the Au layer 21 (film thickness:
0.2-1.5 μm) are sequentially laminated, and the Ni-P
An insulating film 22 is formed on a region of the layer 20 where the Au layer 21 is not stacked. The insulating film 22 is made of a resin such as acrylic, epoxy, silicone, or polyimide, or an inorganic material such as silicon oxide or silicon nitride. The insulating film 22 may be provided on the non-display area 19 except at least the seal portion 15, but may be extended to the seal portion 15 and further to the display area 16 as shown in FIG.

Next, the process of producing the liquid crystal cell 12 will be described in detail. Step A : An ITO film (thickness 500 to 3,000) is formed on one main surface of the glass substrate 14 by sputtering or vapor deposition.
Å) is formed and a plurality of ITO transparent electrodes 18 are linearly arranged in the square or rectangular display region 16 by photoetching. Although not shown, the glass substrate 1
A silver paste for conducting the ITO transparent electrode 18 of No. 4 on the glass substrate 13 is applied.

On the other hand, the IT is also formed on one main surface of the glass substrate 13.
An O film is formed and a plurality of ITO transparent electrodes 17 are linearly arranged in the display region 16 by photoetching, and the ITO transparent electrodes 17 are extended to the non-display region of the glass substrate 13. Thereafter, a Ni-P layer (thickness: 0.3 to 1.0 μm) is provided by electroless plating over the entire ITO transparent electrode 17, and then the Ni-P layer on the display region 16 is removed by etching, as shown in FIG. , The Ni-P on the ITO transparent electrode 17 in the non-display area 19
The layer 20 is provided.

Thereafter, using an oven, 170-250
By heating at a temperature of ℃ for about 1 hour, the adhesion of the Ni-P layer is enhanced. Note that this heating may also serve as a heat treatment when the alignment film is solidified in a later step.

Step B : non-display area 19 of glass substrate 13
An insulating film 22 is formed on a portion of the Ni-P layer 20. When the insulating film 22 is made of resin, it is provided by coating, and when it is made of an inorganic material such as silicon oxide or silicon nitride, it is provided by thin film forming means such as sputtering or vapor deposition.

Step C : An alignment film is applied and formed on the transparent electrode patterns 17 and 18 of each display region 16 of the glass substrates 13 and 14, and the mixture is heated and solidified.

Step D : The surface of the alignment film on each display region 16 of the glass substrates 13 and 14 is rubbed.

Process E : Each glass substrate 13 and 14 is connected to each IT
The O transparent electrode lines 17 and 18 are arranged so as to cross each other and face each other, and then the periphery of the display region 16 is pasted through the seal portion 15 to form an empty cell.

Step F : In this empty cell, the display area 1
A liquid crystal material L is injected into 6 to form a liquid crystal cell. In addition,
A lighting inspection can be performed after this process to remove defective products.

Step G : Glass substrate 13 in liquid crystal cell
An Au layer 21 is provided by electroless plating on the Ni-P layer 20 exposed in the upper non-display area 19.

However, in the case where the Au layer 21 has a structure in which a replacement Au plating layer and a thick Au plating layer are sequentially laminated, the replacement Au plating layer has a Ni--P underlying layer.
It is formed by depositing Au by a substitution reaction with the layer 20, 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.

Step H : A driving semiconductor element (not shown) is mounted on the Au layer 21 on the glass substrate 13, and the terminal of this driving semiconductor element is wire-bonded to the electrode portion of the Au layer 21.

Thus, a COG type liquid crystal display panel in which a driving semiconductor element is mounted on the liquid crystal cell 12 can be formed by the above series of steps. According to such a liquid crystal display panel manufacturing method, resin or Without using a masking technique for applying a resist, a bridge short circuit did not occur, and the production yield in electroless plating was improved, which reduced the production cost.

The present invention is not limited to the above embodiments, and various changes and improvements may be made without departing from the scope of the present invention.

For example, according to the step A of the above embodiment,
The ITO transparent electrode 17 is formed on the glass substrate 13 by etching.
Are arranged in a line, a Ni-P layer is provided over the entire ITO transparent electrode 17, and then the display area 16 is formed.
Although the upper Ni-P layer is removed by etching, the ITO layer and the Ni-P layer may be formed over the entire surface of the glass substrate 13 and then patterned by etching. Alternatively, according to the above embodiment, instead of the Ni-P layer 19, a Ni-B layer, a Ni-Co-P layer, a Ni-C layer is used.
u-P layer, Ni-Cr-P layer, Ni-Fe-P layer, Ni
A -Co-Cr-P layer or the like may be formed. Further, instead of the Au layer 21, a layer selected from Ag, Pd, Pt, Ph and Pu may be provided.

[0028]

As described above, according to the present invention, in the step B, an insulating film is formed on a part of the Ni plating layer in the non-display area of one transparent substrate, which causes a bridge short circuit. Excluded. Therefore, the production yield in electroless plating was improved without using a masking technique for applying a resin or a resist to the liquid crystal cell, and thus the production cost could be 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.

FIG. 4A is an enlarged cross-sectional view of a main part of a conventional liquid crystal display panel, and B is an enlarged plan view of the main part.

[Explanation of symbols]

 12 liquid crystal cells 13 and 14 glass substrate 15 seal part 16 display area 17 and 18 ITO transparent electrode 20 Ni-P layer 21 Au layer 22 insulating film

Claims (1)

[Claims] 1. A method for manufacturing a liquid crystal display panel, which comprises the following steps A to H in sequence. Step A: A transparent electrode pattern is formed on one transparent substrate and the other transparent substrate to provide a square or rectangular display region, and electroless plating is performed on the transparent electrode pattern in the non-display region of one transparent substrate. To provide a Ni plating layer. Step B: An insulating film is formed on a part of the Ni plating layer in the non-display area of one transparent substrate. Step C: Alignment films are formed on the transparent electrode pattern in the display area of one transparent substrate and on the transparent electrode pattern in the display area of the other transparent substrate. Step D: The surface of the alignment film on each display region of the one transparent substrate and the other transparent substrate is rubbed. Step E: One transparent substrate and the other transparent substrate are bonded together via a sealing member made of an adhesive resin arranged along the periphery of the display area to form an empty cell. Step F: A liquid crystal material is injected into a display region between two transparent substrates in an empty cell to form a liquid crystal cell. Step G: An upper plating layer selected from Au, Ag, Pd, Pt, Ph and Pu is provided by electroless plating on the Ni plating layer exposed in the non-display area on one transparent substrate in the liquid crystal cell. Step H: A driving semiconductor element is mounted on the upper plating layer of one transparent substrate, and the terminals of the driving semiconductor element and the upper plating layer are electrically connected.