JPH05150258A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To suppress disconnection at a metal contact part having laminated structure and to provide liq. crystal display device in a high yield of production. CONSTITUTION:A 1st metal wiring 101, a 1st insulating layer 102, a 2nd metal wiring 104, a 2nd insulating layer 103 and a 3rd metal wiring 105 are successively laminated on an insulating substrate. Each of the 1st insulating layer 102 and the 2nd insulating layer 103 has a contact hole and the contact hole in the layer 103 does not overlap the contact hole in the layer 102. The 1st metal wiring 101, the 2nd metal wiring 104 and the 3rd metal wiring 105 are electrically connected to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device. In particular, the present invention is used in the peripheral wiring section.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been attracting attention as displays replacing CRTs, and improvements have been made toward higher image quality and larger screens. For this reason, new materials are being used, and manufacturing processes and structures suitable for this are being investigated.

An example of the above-mentioned conventional liquid crystal display device will be described below with reference to the drawings. (Fig. 3) is a cross-sectional view of a conventional liquid crystal display device. (Figure 3)
, 301 is a first metal wiring, 302 is a second metal wiring, 303 is a pixel switching element, 304 is a pixel electrode, 305 is a transparent electrode, 306 is a first insulating layer, 307
Is a second insulating layer, 308 is an insulating substrate, 309 is a liquid crystal layer,
310 is a counter substrate and 311 is a seal resin. (For example, Video Information (I), September 1989 issue, pages 23 to 31).

The structure of the wiring portion particularly related to the present invention is extracted as shown in FIG. 401 is a first metal wiring, 402 is a first insulating layer, 403 is a second insulating layer, 404 is a second metal wiring, and 405 is an insulating substrate.

FIG. 3 shows an inverted stagger type thin film transistor, which is the most widely used liquid crystal display device.
It is an example using. In this case, the first metal wiring 401 is a scanning line (gate). Although chromium has been most widely used as a material of the first metal wiring 401 until now, aluminum has come to be used in recent years as the image quality and the screen size of the display become larger.

First insulating layer 402 and second insulating layer 403
Often has a two-layer structure like this in order to enhance the insulating effect, and the materials are the first insulating layer 402 and the second insulating layer 403.
Often different things. For example, the first insulating layer 402 is tantalum oxide, the second insulating layer 403 is silicon nitride, or the like. Recently, the first insulating layer 402 may be formed by anodic oxidation of the first metal wiring 401.
For example, the first metal wiring 401 is aluminum and the first insulating layer 402 is aluminum oxide.

[0007]

However, in the above structure, the contact hole of the first insulating layer 402 and the contact hole of the second insulating layer 403 are overlapped. The first metal wiring 40 in this overlapping portion
No. 1 receives some damage twice when the contact hole of the first insulating layer 402 is formed and when the contact hole of the second insulating layer 403 is formed.

Particularly in the case of a material such as aluminum, which has been often used in recent years, which is weak against chemicals, there is a particular problem, and in the worst case, the first metal wiring 401 disappears when the contact hole is formed. The electrical connection with the metal wiring 404 is lost, resulting in disconnection. If this is a scanning line or a signal line, the display on the display will be a line defect.

In view of the above problems, the present invention provides stable electrical connection even if a metal material having poor chemical resistance is used.
It is intended to provide a liquid crystal display device without breakage.

[0010]

In order to solve the above-mentioned problems, a liquid crystal display device of the present invention has a contact hole of a first insulating layer and a contact hole of a second insulating layer arranged at different positions, Further, a new metal wiring is arranged between the first insulating layer and the second insulating layer, and the contact hole of the first insulating layer and the second
The structure is characterized in that the contact holes of the insulating layer are electrically connected.

[0011]

According to the present invention, the first metal wiring under the contact hole of the first insulating layer has the structure described above.
It is only exposed to the rule forming process once, reducing damage. In particular, as the first insulating layer is often formed by anodic oxidation as described above, the contact hole of the first insulating layer should be formed by selective anodic oxidation, not by conventional etching. You can in this case,
The contact hole of the first insulating layer can be formed without giving any damage to the first metal wiring.

In the case of a thin film transistor, the material of the first metal wiring is often a gate. In the past, a chemically stable material such as chromium was often used in consideration of manufacturing stability. However, in recent years, with the increase in size and definition of displays, it has become necessary to reduce the resistance of gate materials, and materials such as aluminum have come to be used. However, aluminum has been chemically and thermally unstable, making display manufacturing extremely difficult.

In the structure of the present invention, since the damage given to the first metal wiring can be reduced as described above, the selection range of the material of the first metal wiring can be widened. A display can be easily manufactured using the aforementioned aluminum.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of a wiring portion of a liquid crystal display device according to a first embodiment of the present invention. 101 is a first metal wiring, 102 is a first insulating layer, 103 is a second insulating layer, 104 is a second metal wiring, 105 is a third metal wiring, and 106 is an insulating substrate.

The structure of this embodiment is often used in the wiring portion of a liquid crystal display device. When it is desired to convert the metal material, for example, the configuration in which the first metal wiring 101 is aluminum and the third metal wiring 105 is ITO is used for a connection portion with another element or a flexible substrate. Further, when the isolated first metal wiring 101 is electrically connected using the third metal wiring 105, this structure is provided at two places, and the first metal wiring-second
, The third metal wiring, the second metal wiring, and the first metal wiring are electrically connected in this order. This is used when connecting intricate wiring such as a power supply line and a line for relief of disconnection in the peripheral portion of the substrate.

An example of manufacturing this structure will be shown. First, the first metal wiring 101 (made of aluminum, for example) is patterned into a predetermined shape, and then a part of it is masked and anodized to form a first insulating layer 102. After that, the second metal wiring 103 is formed, and the first metal wiring 10 is further formed.
The pattern is made in such a manner that it makes an electrical connection with 1. After that, a second insulating layer 103 is formed (for example, using silicon nitride as a material), and a contact hole is formed on the second metal wiring 104 other than on the unformed portion of the first metal wiring 101. -Lease by etching. After that, the third metal wiring 105 is formed and patterned to electrically connect the first metal wiring 101, the second metal wiring 104, and the third metal wiring 105.

Second metal wiring 104 and third metal wiring 1
The material of 05 is selected as required. For example, it is chromium, ITO, aluminum, titanium, molybdenum, tantalum, tungsten, or an alloy containing any of these as a main component. Further, in the above description, the metal wiring is expressed as a single layer, but it is not limited to a single layer, and may be formed of a multilayer film.

Further, in the above-mentioned example, the first insulating layer 102
However, the present invention is not limited to this and may be formed by sputtering, various CVD methods, printing, coating, or the like. At this time, the contact hole of the first insulating layer 102 is formed by etching.

When the first insulating layer 102 is formed by the anodic oxidation method, the material of the first metal wiring 101 is limited to a material that can be anodized. For example, aluminum, tantalum, titanium, or an alloy containing any of these as a main component. When the anodizing method is not used, the metal used is not limited, and for example, chromium, ITO, aluminum, titanium, molybdenum, tantalum, tungsten, or an alloy containing any of these as the main component can be used.

FIG. 2 is a sectional view of the wiring portion of the liquid crystal display device according to the second embodiment of the present invention. 20
1 is the first metal wiring, 202 is the first insulating layer, 203 is the second insulating layer, 204 is the second metal wiring, and 205 is the third.
Of metal wiring, and 206 is an insulating substrate.

In this structure, since the first metal wiring 201 is not provided under the contact hole of the second insulating layer 103, the second
Even if some defects such as pinholes occur in the metal wiring 204 and the first insulating layer 202, the first metal wiring 201 is not affected.

In the first and second embodiments, the contact hole is expressed in the shape of a hole, but the present invention is not limited to this, and it means a portion where the insulating layer is removed to obtain a contact. However, the shape is not limited to the hole shape.

[0023]

INDUSTRIAL APPLICABILITY As described above, the present invention is a liquid crystal display device having a laminated structure, and even if a material having chemical stability is used in the lower layer, disconnection does not occur, and the manufacturing yield of the liquid crystal display device is improved. Improve.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional liquid crystal display device.

FIG. 4 is a cross-sectional view of a contact portion of a conventional liquid crystal display device.

[Explanation of symbols]

 101 First Metal Wiring 102 First Insulating Layer 103 Second Insulating Layer 104 Second Metal Wiring 105 Third Metal Wiring 106 Insulating Substrate 201 First Metal Wiring 202 First Insulating Layer 203 Second Insulation Layer 204 Second metal wiring 205 Third metal wiring 206 Insulating substrate 301 First metal wiring 302 Second metal wiring 303 Picture element switch element 304 Picture element electrode 305 Transparent electrode 306 First insulating layer 307 Second Insulating layer 308 Insulating substrate 309 Liquid crystal layer 310 Counter substrate 311 Seal resin 401 First metal wiring 402 First insulating layer 403 Second insulating layer 404 Second metal wiring 405 Insulating substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ikunori Kobayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A first metal wiring, a first insulating layer, a second metal wiring, a second insulating layer, and a third metal wiring are sequentially laminated on an insulating substrate, and the first insulating layer is formed. The layer and the second insulating layer each have a contact hole, and the contact hole of the second insulating layer is in a position not overlapping the contact hole of the first insulating layer. In addition, the liquid crystal display device is characterized in that the first metal wiring, the second metal wiring, and the third metal wiring are electrically connected. 2. A first metal wiring, a first insulating layer, a second metal wiring, a second insulating layer, and a third metal wiring are sequentially laminated on an insulating substrate, and the first insulating layer is formed. The layer and the second insulating layer each have a contact hole, and the contact hole of the second insulating layer is in a position not overlapping the contact hole of the first insulating layer. In addition, the first metal wiring is not present below the contact hole of the second insulating layer, and the first metal wiring, the second metal wiring, and the third metal wiring are electrically connected. A liquid crystal display device characterized by being connected. 3. The liquid crystal display device according to claim 1, wherein the first metal wiring is aluminum or an aluminum alloy. 4. The liquid crystal display device according to claim 1, wherein the second metal wiring is chromium, ITO or an alloy thereof.