JP2000250059A - Passive matrix type liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a passive matrix type liquid crystal device having good display quality, excellent corrosion resistance, large number of pixels and narrow frames while suppressing production of failures due to short circuits, discontinuity of lines or the like, and with excellent productivity at a low cost by forming a wiring electrode pattern consisting of a metal-based conductive member on the inner face of a pair of substrates. SOLUTION: A wiring electrode pattern 2 consisting of a metal-based conductive member is formed. That is, a film of the metal-based conductive member is formed by sputtering all over the one surface of a substrate 1. Then a resist liquid is applied thereon, subjected to photolithographic processes such as exposing, developing, etching and peeling to form a desired wiring electrode pattern. Then an ITO transparent conductive film is formed by sputtering on the surface of the substrate where the wiring electrode is formed, and then subjected to the same photolithographic processes to form pixel electrodes 3. As for the counter substrate, a substrate having a pattern formed only of an ITO transparent conductive film is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wiring electrode formed on a substrate such as a glass substrate or an organic film used in a passive matrix type liquid crystal device.

[0002]

2. Description of the Related Art In recent years, electro-optical devices, particularly liquid crystal display devices, have been rapidly increasing in density and definition, and even in passive matrix type liquid crystal devices for portable equipment, more and more devices have been installed in a small external size. Pixels and a larger display area (= multiple pixels / narrow frame) must be secured.

In such an inexpensive passive matrix type liquid crystal device, it is common to form a pixel electrode and a wiring electrode by patterning ITO, which is a transparent conductive film, by a photolithography method. In addition, a COG (Chip) in which a driving semiconductor element is mounted on a glass substrate
In an OnGlass (chip-on-glass) type liquid crystal device, in order to secure a sufficient amount of current to drive the driving semiconductor, Ni-P or Ni-B plating is performed on the ITO transparent conductive film. There has been proposed a structure in which a metal such as Au is formed on a film or a film obtained by combining them by a vapor deposition method, a sputtering method, an electroless plating method, or the like (Japanese Patent Laid-Open No. 3-64869, Japanese Patent Laid-Open No. 63-2553).
No. 77).

[0004]

However, as described above, there is a limit to ultrafine patterning of an ITO transparent conductive film. One is due to the good chemical stability. Patterning of the ITO transparent conductive film is usually performed with a heated hydrochloric acid-based etching solution or a ferric chloride-based etching solution. However, although the etching property of the ITO transparent conductive film is not bad as compared with tin oxide which is the same transparent conductive film, the workability is not necessarily good. As a result, due to high density and high definition, the smaller the gap between the pixel and the wiring electrode, the more likely it is that disconnection occurs due to short-circuiting or over-etching due to poor etching, making it difficult to form wiring with good yield. .

[0005] Further, by reducing the width of the wiring electrode for high density and high definition, the relatively large resistance value (10 to 200 Ω / □) of the ITO transparent electrode cannot be ignored, and the voltage drop and the current shortage occur. And so on, and eventually the display quality is degraded. Further, the above-described structure in which a metal such as Au is formed on a film of Ni-P or Ni-B based on the ITO transparent conductive layer and a film obtained by combining them can solve the problem of the resistance value. However, it is difficult to form a wiring with a high yield, as is the case with ultra-fine patterning of an ITO transparent conductive film.

In addition, a metal such as Au formed on the surface is
Since the hardness is low, it is easily scratched, and corrosion proceeds from the scratched portion, so that care must be taken in handling. Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to provide a multi-pixel, narrow-frame, passive-matrix liquid crystal device with excellent corrosion resistance while suppressing the occurrence of defects due to short-circuiting, disconnection, and the like. It is to be able to obtain at low cost by excellent mass productivity.

[0007]

In order to solve the above-mentioned problems, the present invention is to form a wiring electrode pattern made of a metal-based conductive member. Metallic conductive members are IT
Since the resistance value is lower than that of the O transparent conductive film, a voltage drop or the like due to wiring resistance can be reduced, so that the width of the wiring electrode can be further reduced.

Further, a film can be easily formed by a vapor deposition method, a sputtering method, or the like, and by using a material having excellent etching properties, patterning becomes easy, and a wiring electrode with a narrow electrode gap can be formed at low cost with good yield. In addition, by using a material having high hardness and not being affected by air or water at normal temperature, corrosion resistance can be improved and reliability can be improved, and the manufacturing process can be simplified.

In particular, metal chromium is a material widely used in general industrial products, and is characterized by excellent availability and processability. In a COG liquid crystal device, a sufficient amount of current can be supplied to drive a driving semiconductor, and good display quality can be ensured. The liquid crystal device configured as described above can be easily manufactured with high yield despite being a multi-pixel, narrow-frame, passive-matrix liquid crystal device.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic plan view showing a first embodiment of a substrate used in a liquid crystal device according to the present invention. Substrate 1
First, a metal conductive member is formed on the entire surface of one surface by a sputtering method. Here, metallic chromium was used as the metallic conductive member. The film forming method is not limited to the sputtering method, but may be an evaporation method, an ion plating method, or the like. Next, after a resist solution was applied on the same surface, a desired wiring electrode pattern 2 was formed by a photolithography process such as exposure, development, etching, and peeling. In addition, in pattern formation,
When higher definition and higher precision are required, the pattern may be directly formed by an electron beam or the like, without being limited to the photolithography method. Next, an ITO transparent conductive film was formed on the surface of the substrate on which the wiring electrodes were formed by a sputtering method, and the pixel electrodes 3 were similarly formed by a photolithography method. At this time, a part of the wiring electrode may be formed of the ITO transparent conductive film. The opposite substrate may be the same substrate as described above in which the wiring electrodes are formed of a metal-based conductive member. However, for inexpensive production, it is preferable to use a substrate formed with a pattern using only the ITO transparent conductive film. desirable. In this case, the wiring electrode pattern made of a metallic conductive member corresponding to a part of the ITO transparent conductive film pattern on the opposing substrate is made of a vertically conductive material such as a plastic bead whose surface is coated with a metal such as gold, Ag or the like. Are electrically connected by the paste described above, and connection terminals are provided only on one of the substrates.
(However, the present invention is not limited to this structure.) FIG.
FIG. 2B is a schematic plan view of a liquid crystal panel used in a conventional liquid crystal device, and FIG. 2B is a schematic plan view of a liquid crystal panel used in a conventional liquid crystal device. According to the present invention, as shown in the figure, the area of the wiring electrode portion 7 can be reduced by forming an extremely fine pattern, and as a result, a large display screen can be obtained when substrates having the same external size are used. .

Example 2 A wiring electrode was formed in the same manner. Since a material which is easy to form a film and has excellent etching properties is used for the metal-based conductive member, a wiring electrode having an extremely fine pattern can be easily formed at low cost. (Example 3) Wiring electrodes were formed in the same manner. Since the metal-based conductive member is made of a material that is hard and does not corrode with air or water at around normal temperature, there is no scratch on the surface, and there is no need to provide an antioxidant film on the surface of the metal-based conductive member. This improves the simplification of the process and improves the handleability, and as a result, can form an extremely fine pattern wiring electrode at low cost.

Example 4 A wiring electrode was formed in the same manner. Metal chromium is used for the metal-based conductive member.
Since the specific resistance of metallic chromium is high (the specific resistance values of the main metals are shown in Table 1), it is not a material exhibiting good electrical conductivity compared to other metals such as Al, Cu, and Au. Although it is not used as a wiring material, it is easy to form a film, has excellent etching properties, has high hardness, and has a property that it is not eroded by air or water at around normal temperature. Further, it is a material widely used in general industrial products, and is excellent in availability. Therefore, a wiring electrode having an extremely fine pattern can be formed at low cost.

Example 5 A wiring electrode was formed in the same manner. Metallic chromium was used for the metal-based conductive member, and its film thickness was set to 500 Å. The sheet resistance of the metal chromium thus formed was about 5Ω / □. The sheet resistance of the ITO transparent conductive film is 10 to 200Ω.
/ □, the use of metal chromium having a film thickness of more than this makes it possible to obtain a wiring electrode having an extremely fine pattern while keeping the resistance value low.

Example 6 A wiring electrode was formed in the same manner. Here, wiring electrodes for the driving semiconductor element are also formed at the same time. When the wiring electrodes are formed in this manner, a sufficient amount of current for driving the semiconductor requiring driving can be easily secured, but a new process does not need to be added, and a liquid crystal device having excellent display quality can be obtained.

[0015]

As described above, according to the present invention, a multi-pixel, narrow-frame, passive-matrix liquid crystal device having good display quality and excellent corrosion resistance while suppressing the occurrence of defects due to short-circuiting, disconnection, etc. Excellent mass productivity enables low cost production.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a substrate used in a liquid crystal device according to the present invention.

FIG. 2A is a schematic plan view of a liquid crystal panel used in a liquid crystal device according to the present invention. (B) It is a plane schematic diagram of the liquid crystal panel used for the conventional liquid crystal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Wiring electrode pattern 3 Pixel electrode 4 Wiring electrode part 5 Display screen

Claims (6)

[Claims] 1. A passive matrix liquid crystal device having a liquid crystal mixture sandwiched between a pair of substrates, wherein a wiring electrode pattern made of a metal-based conductive member is formed on inner surfaces of the pair of substrates. Liquid crystal device. 2. The liquid crystal device according to claim 1, wherein the metal-based conductive member is a material which is easy to form a film and has excellent etching properties. 3. The liquid crystal device according to claim 1, wherein the metal-based conductive member is made of a material having a high hardness and not being affected by air or water at around normal temperature. 4. The liquid crystal device according to claim 1, wherein the metal-based conductive member is metal chromium. 5. The method according to claim 1, wherein the thickness of the metallic chromium is at least 5
5. The liquid crystal device according to claim 4, wherein the thickness is not less than 00 angstroms. 6. The liquid crystal device according to claim 1, wherein a driving semiconductor element is mounted on the substrate.