JPS63229431A - Liquid crystal display panel and its manufacturing method - Google Patents

Abstract

PURPOSE:To effectively prevent the titled panel from the corrosion of a metal wiring at a high temp. and humidity by electrochemically treating the wiring with a neutral electrolyte after forming the wiring on a wiring board, thereby forming a substantial nonporous oxide film on the surface of the wiring. CONSTITUTION:The thin and substantial nonporous oxide film is formed on the surface of the titled panel by electrolyzing the metal wiring of the liquid crystal display panel mounting an electronic circuit element thereon, in the neutral electrolyte. And as necessary, a protective film composed of an epoxy resin, etc., is formed on the surface of the oxide film. Thus, the titled panel having no fear of the corrosion of the wiring, even at the high temp. and humidity, and capable of holding sufficiently reliable even when it is used for a display element of an automobile, etc., is obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to liquid crystal display panels used in automobile instrument panels, office automation equipment, etc., particularly liquid crystal display panels, EL panels, etc. in which driving electronic circuit elements are integrally mounted. The present invention relates to a liquid crystal display panel and its manufacturing method.

[Conventional technology]

In recent years, graphic displays have become widely used as man-machine interfaces, and along with this, liquid crystal display devices have also come to be used in automobile instrument panels.
This trend tends to accelerate as color liquid crystal display elements become more practical.

By the way, in such a liquid crystal display device (hereinafter referred to as a liquid crystal display panel), by taking advantage of its panel-like form, one side of the electrode substrate is expanded, and a driving electronic circuit element is installed in this expanded part. (LSI) is directly mounted and both are modularized. In addition, regarding such an example, for example, Japanese Patent Application Laid-Open No. 53-60199,
This is disclosed in Japanese Unexamined Patent Publication No. 53-104198.

Therefore, a conventional example of such a liquid crystal display panel will be explained with reference to FIG. 2.

This FIG. 2 shows a liquid crystal display panel composed of a glass substrate 1, a large substrate 1, and a glass substrate 2 which is an electrode substrate.
On the glass substrate 2, an LSI chip 4 for driving a liquid crystal display panel is fixed using an adhesive 5, and is mounted by connecting it to a wiring circuit using Au and Al wire lines 6. . This liquid crystal display section and LSI chip 4
The metal wiring 7 between the terminals of the LSI chip 4 and the metal wiring A8 between the terminals of the LSI chip 4 and the terminals for connection with an external circuit are made of the same conductive material, for example, a conductor layer made of a Cr-Cu bilayer film or a Cr-Cu bilayer film. .

Further, in FIG. 2, reference numeral 3 denotes a sealant for sealing the liquid crystal sandwiched between the glass substrates 1.degree. Although it is omitted because it is difficult to show in FIG. 2, a protective resin is actually provided to cover the LSI chip 4.

Next, FIG. 3 shows a cross section taken along the line AA' in FIG. 2, and in this FIG. 3, 1.2 is a glass substrate;
3 is a sealant, 4 is an LSI chip, 5 is an adhesive, 6 is a wire line, and 7 and 8 are metal wirings, each of which is made of a Cr--Cu two-layer film or an Aρ film. 9 is a liquid crystal layer, and 10 and 11 are transparent electrodes made of a transparent conductive film made of InZO3+ 5nOz or a mixture thereof.

Incidentally, a liquid crystal display panel mounted with an LSI chip having such a structure is required to have various types of reliability. This reliability evaluation is divided into two types: non-energized reliability tests and energized current reliability tests. Note that the electrical conductivity test is an operation test of a liquid crystal display panel under various conditions.

First, in the non-current reliability test, high temperature storage (90℃-
500h), left at high temperature (70℃/95%RH)
1000h), temperature/humidity cycle (-30℃470℃/9
5%RH140ψ), temperature cycle (-30℃#+80
°C, 500ψ or more), vibration test (LOG, 10-50
0Hz-100h each).

Therefore, the various non-current reliability tests described above were conducted on conventional liquid crystal display panels having the structures shown in FIGS. 2 and 3. As a result, corrosion of the wiring was observed during the high-temperature test, and it was found that the target specifications were not met.

In addition, in the above-mentioned conventional liquid crystal display panel, a synthetic resin film such as epoxy resin is usually formed on the surface to protect the metal wiring, but such a synthetic resin film is not moisture-proof. It is not possible to effectively prevent corrosion of metal wiring under high temperature and high humidity conditions as described above.

Therefore, when the metal wiring of conventional LCD panels corrodes during high-temperature tests, the wiring breaks over a long period of time, leading to display defects and significantly reducing the reliability of the LCD panel. and
Moreover, as a product, it is incomplete.

[Problem that the invention seeks to solve]

As described above, conventional liquid crystal display panels have a problem in that it is difficult to maintain sufficient reliability when used in automobiles and the like.

The purpose of the present invention is to solve the above-mentioned problems of the conventional technology, and to be able to maintain sufficient reliability even when used in display elements of automobiles, etc., without fear of wiring corrosion even under high temperature and high humidity conditions. The company provides liquid crystal display panels.

[Means for solving problems]

To achieve this objective, the present invention provides an electronic circuit element with t
The main idea is to electrolytically treat the metal wiring of a liquid crystal display panel in a neutral aqueous solution to form a thin, substantially non-porous oxide film on its surface.

That is, the first invention of the present invention relates to a liquid crystal display panel, and the gist of the invention is as follows: ``One of the electrode substrates of the display element is expanded to form a wiring board, and the wiring board is equipped with electronics for driving the display element. A liquid crystal display panel equipped with a circuit element, characterized in that the wiring constituting the circuit element is made of a conductor with a substantially non-porous oxide film formed on its surface.'' The second invention relates to a method for manufacturing the liquid crystal display panel, and the gist of the invention is as follows: ``One of the electrode substrates of the display element is expanded to form a wiring board, and a wiring board for driving the display element is provided on the wiring board. In a method for manufacturing a liquid crystal display panel equipped with electronic circuit elements, after wiring is formed on a wiring board, the wiring is electrochemically treated with a neutral electrolyte to substantially coat the wiring surface. A method for manufacturing a liquid crystal display panel characterized by forming a non-porous oxide film.

"It is in.

The present invention as described above has been made based on the following findings. In other words, the inventors of the present invention believe that in order to prevent the corrosion of metal wiring as described as a problem with the prior art, it is first necessary to avoid contact with moisture.
We considered coating metal wiring with organic or inorganic materials. Therefore, as a pinhole test of the material coated on the wiring, that is, a method to evaluate the throwing power on the wiring, the wiring is coated with polyimide resin, water droplets are dropped on the surface, and a voltage is applied to the metal wiring. The company was investigating the melting state of the wiring. At that time, it was found that in the case of Al wiring, even if there were pinholes in the polyimide resin, no dissolution current would flow.

It is assumed that this phenomenon is due to the fact that the AN wiring surface that has come into contact with the aqueous solution is sufficiently dense, that is, a substantially non-porous oxide film is formed from the viewpoint of moisture-proofing and corrosion-proofing properties, preventing dissolution. . Therefore, the Al wiring was electrolytically treated with a neutral aqueous solution, that is, the Al wiring was made into a ■ pole, and a DC voltage of 50
The treatment was performed by applying V. This sample was heated to a high temperature (70°C).
/95%R11) As a result, it was discovered that corrosion of the Al wiring did not occur at all. In other words, i
It was revealed that by electrolytically treating the wiring in a neutral aqueous solution, the substantially non-porous oxide film is formed on the surface, and this is effective in preventing corrosion.

The results are shown below. FIG. 4 shows a test pattern for high temperature and high temperature tests. This pattern has a comb-like structure, so that only one side of the pattern can be selectively electrolyzed. Therefore, the pattern shown in FIG. 4 was fabricated using A6 as the wiring material. Therefore, next, using pure water (pH = 7.0) as the electrolyte, one terminal of the pattern in Figure 4 was set as the ■ pole, and a DC voltage of 50V was applied.
Electrolytic treatment was performed for 60 seconds. Therefore, the other pattern has not been electrolytically treated. The high-temperature, high-temperature test pattern thus prepared was subjected to a high-temperature, high-humidity test (70"C/95%R), which is a reliability evaluation test. As a result, after 506 hours of the high-temperature and high-temperature test, electrolytic treatment was alternately applied. It was confirmed that no corrosion occurred in the Al pattern that had been subjected to electrolytic treatment.On the other hand, complete corrosion was observed in the Al pattern that had not been electrolytically treated.

By electrolytically treating with a neutral aqueous solution in this way, 1M
It was confirmed that corrosion of wiring was prevented and reliability was improved. The reason why this corrosion is prevented is thought to be that a thin, dense oxide film is formed on the Al surface by the electrolytic treatment, and the results of examining the thickness of the oxide film are shown in FIG. In FIG. 5, the vertical axis shows the thickness of the oxide film, and the horizontal axis shows the applied voltage.

Note that the electrolytic solution was pure water (pH=7.0), and the application time was 60 seconds. It has also been confirmed that the electrolytic current flows rapidly when voltage is applied, but immediately drops to almost no longer flowing. Therefore, the thickness of the oxide film produced is proportional to the applied voltage.

Since the sample subjected to the above-mentioned high-temperature high-temperature test had an applied voltage of 50 V, the thickness of the oxide film was about 400 people (
(see FIG. 5), and it was confirmed that even a film thickness of this level can sufficiently withstand reliability. Furthermore, the thickness of the oxide film is 300 mm.
Human samples are subjected to high-temperature tests (70'c/
As a result, it was confirmed that no corrosion of the Aε wiring was observed. Therefore, the minimum thickness of the oxide film is 3
I decided that 6'11 should be 00 Å or more.

As described above, in the present invention, the oxide film formed on the surface of the wiring constituting the circuit element has sufficient density to impart sufficient corrosion resistance to the wiring under high temperature and high humidity conditions, that is, the oxide film is moisture-proof. It is substantially non-porous from the viewpoint of corrosion resistance and corrosion resistance. Such a non-porous oxide film is formed by using a neutral electrolyte in electrochemical treatment, and unlike conventionally known alumite, the electrolyte is In the following acidic conditions, the oxide film formed is 300~
The result is a porous material with 400 holes, and the desired density cannot be obtained.

Furthermore, such a porous oxide film does not have the required performance in terms of electrical insulation.

As mentioned above, AI is the material that makes up the wiring! Although the case where AI! is used has been described, the material constituting the wiring in the present invention may be AI! In addition, CIJ, Ti, etc. can also be used.

[For production]

The present invention is arranged as described above! By electrolytically treating the wiring formed on the rr'A substrate in a neutral aqueous solution, a sufficiently dense oxide film, that is, a substantially non-porous oxide film from the viewpoint of moisture and corrosion resistance, is formed on the surface. , Corrosion of the wiring under high temperature and high humidity is prevented. As a result, there will be no disconnection or short circuit of the wiring.
It was confirmed that malfunctions such as display defects were eliminated and reliability was improved.

〔Example〕

Hereinafter, the liquid crystal display panel according to the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the liquid crystal display panel of the present invention. In FIG. 1, 1 2 is a glass substrate, 3 is a sealant, and 4 is an L
SI chip, 5 is adhesive, 6 is wire line, 7 and 8 are metal wiring, 9 is liquid crystal layer, 10 and 11 are InzOx, 5
This is a transparent electrode made of a transparent conductive film made of n02 or a mixture thereof.

Reference numerals 12 and 13 are oxide film layers formed on the surfaces of the metal wirings 7 and 8. 14 is a coating resin, L
This is to protect the SI chip.

The liquid crystal display section 100 has a structure in which a liquid crystal layer 9 is sandwiched between a glass substrate 1 and a glass substrate 2.

A transparent electrode 10 is formed on the glass substrate 1, and a transparent electrode 11 is formed on the glass substrate 2. This transparent electrode 11 is
It comes out from the liquid crystal display element part, and metal wirings 7 and 8 are partially laminated there to ensure electrical connection.

According to the present invention, since a dense oxide film layer is provided on the surfaces of the metal wirings 7 and 8, corrosion is prevented in high-temperature tests, and there is no melting or disconnection of the wiring, thereby improving reliability. I was able to do that.

Table 1 shows the high temperature test results of the liquid crystal display panel according to this example.

Table 1 High temperature high temperature test (70℃/95%R11) results○
: No wiring corrosion occurred × : Wiring corrosion occurred In Table 1, for comparison, the metal wiring is Cr-Cu.
Two layer membrane, A! A liquid crystal display panel made of a film (not subjected to electrolytic treatment) is also shown. Table 1 shows that the thickness of the metal wiring 7.8 in the embodiment shown in FIG. 1 is constant at 2.0 μm. Among these, the thickness of the oxide film layer on the AN wiring in this embodiment is 150.300°430.

As is clear from this, the high temperature test (70/95%
It was confirmed that in order to satisfy R1+-1000 hours), the thickness of the oxide film layer should be 300 Å or more.

Then, if necessary, on the surface of the oxide film,
By forming a protective film using epoxy resin etc.
The wiring surface can be further protected from contamination and the like.

In the present invention, a dense oxide film layer is formed on the wiring surface by electrolytic treatment in a neutral aqueous solution to prevent corrosion of the wiring by water. However, if the metal wiring is not electrolytically treated, Therefore, it would be extremely effective to have an electrolytic solution that would form a dense film on the surface of metal wiring simply by immersing it in the solution.

Regarding the characteristics of such an electrolytic solution, it is considered that a neutral solution is preferable, rather than a weak acid or alkaline solution.

Furthermore, if conductive resin could be used as a wiring material for liquid crystal display panels, there would be no problem of corrosion under high temperature and high humidity conditions.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to eliminate corrosion of metal wiring in a liquid crystal display panel equipped with electronic circuit elements, and therefore it is possible to solve the problems of the conventional technology and also to improve yield. , a display panel that can maintain sufficient reliability for use in automobiles and the like can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the liquid crystal display panel of the present invention;
Fig. 2 is a perspective view of an example of a conventional liquid crystal display panel, Fig. 3 is a cross-sectional view taken along line AA' in Fig. 5, Fig. 4 is a schematic diagram showing a test pattern for high-temperature high-temperature testing, and Fig. 5 is a characteristic diagram showing the relationship between oxide film thickness and applied voltage during electrolysis. 1.2...Glass substrate, 3...Sealing agent, 4...L
SI chip, 5...adhesive, 6...wire wire, 7,
8... Metal wiring, 9... Liquid crystal layer, 10.11...
Transparent electrode, 12.13... Oxidation layer, 14... Coating resin, lOO... Liquid crystal display part

Claims (1)

[Scope of Claims] 1. In a liquid crystal display panel in which one of the electrode substrates of a display element is expanded to form a wiring board, and electronic circuit elements for driving the display element are mounted on this wiring board, wiring constituting the circuit element. A liquid crystal display panel comprising a conductor having a substantially non-porous oxide film formed on its surface. 2. The liquid crystal display panel according to claim 1, wherein the wiring is an Al wiring and the oxide film is an aluminum oxide film. 3. The liquid crystal display panel according to claim 1 or 2, wherein the oxide film has a thickness of 300 Å or more. 4. In a method for manufacturing a liquid crystal display panel in which one of the electrode substrates of a display element is expanded to form a wiring board and electronic circuit elements for driving the display element are mounted on this wiring board, after wiring is formed on the wiring board. , the wiring is treated with a neutral electrolyte,
A method for manufacturing a liquid crystal display panel, characterized in that a substantially non-porous oxide film is formed on the surface of the wiring by electrochemical treatment. 5. The neutral electrolyte has a hydrogen ion concentration of 6 to 8 (pH = 6
The method for manufacturing a liquid crystal display panel according to claim 4, wherein the aqueous solution is in the range of 8) to 8). 6. The method of manufacturing a liquid crystal display panel according to claim 4 or 5, wherein the wiring is an Al wiring and the oxide film is an aluminum oxide film.