JP2007192925A - Wiring board and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board capable of attaining low resistance of wiring and improving reliability without changing film thickness and width, and to provide a liquid crystal display comprising the wiring board. <P>SOLUTION: In the wiring board having such a structure that first wiring, an insulating film and second wiring are stacked in this order, the wiring board has a conductive part in a region facing the second wiring under the insulation film, the insulation film has an opening part of exposing the conductive part to the second wiring side and the second wiring covers the opening part of the insulation film and is connected with the conductive part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a wiring board and a liquid crystal display device. More specifically, the present invention relates to a wiring board and a liquid crystal display device that are preferably used as components of a liquid crystal display panel.

Wiring boards are used as components of electronic devices such as liquid crystal display devices, organic electroluminescence (EL) display devices, and solar cells. As the manufacturing technology of these electronic devices advances, Manufacturing technology is becoming increasingly sophisticated.

Hereinafter, an active matrix substrate constituting the liquid crystal display panel will be described as an example.
In general, an active matrix substrate is provided with a thin film transistor (TFT) as a switching element at the intersection of an m × n matrix wiring composed of m rows of scanning lines (gate wiring) and n columns of data lines (source wiring). Have a structured. An address signal (line sequential scanning signal) is supplied to the scanning lines, and a parallel display signal whose polarity is inverted every frame scanning period is supplied to the data lines. Of these, the parallel display signal is written to the capacitance of each pixel via a TFT that is controlled to be turned on / off by an address signal, and is based on the potential difference between the voltage supplied to the pixel electrode and the voltage supplied to the counter common electrode. The liquid crystal on each pixel electrode operates.

As a method of reducing the resistance of such a data line, there is a method of increasing the thickness and width (pattern width) of the data line to increase the cross-sectional area of the wiring. However, there is room for improvement in that it cannot be easily realized due to problems such as restrictions on the pattern layout and processing capability of the manufacturing apparatus.

On the other hand, a semiconductor device formed by stacking a semi-cylindrical or semi-columnar second signal or power wiring on a semi-cylindrical or semi-cylindrical first signal or power wiring formed on a semiconductor substrate. Is disclosed (for example, see Patent Document 1). As a result, the resistance of the semiconductor device can be reduced as compared to a flat wiring with one layer, and the area of the semiconductor device can be reduced. However, there is room for improvement in that the controllability of processing when processing the base is poor and an arbitrary wiring resistance cannot be obtained.

Further, the conductive portion forming the pixel electrode also forms a conductor track on the insulating layer above the conductor line, and the conductor track is connected to the conductor line through at least one contact opening formed in the insulating layer. A liquid crystal display device is disclosed (for example, see Patent Document 2). However, there is room for improvement in terms of complicating the process and reducing yield.
Japanese Patent Laid-Open No. 4-196225 Special Table 2002-530719

The present invention has been made in view of the above situation, and an object thereof is to provide a wiring board and a liquid crystal display device capable of reducing the resistance and improving the reliability of the wiring without changing the film thickness and width. It is what.

The inventors of the present invention have made various studies on reducing the resistance of data lines in a wiring board having a structure in which a scanning line (first wiring), an insulating film, and a data line (second wiring) are stacked in this order. Focusing on the provision of the conductive portion in the same layer or the like. Therefore, a conductive part is provided in a region facing the data line under the insulating film, an opening is formed in the insulating film to expose the conductive part on the data line side, and the opening of the insulating film is covered and connected to the conductive part. As a result, by forming the data line, the cross-sectional area of the data line can be increased. As a result, it has been found that the resistance of the data line can be reduced without changing the film thickness and the pattern width. Moreover, since such a data line has a laminated structure in the region connected to the conductive portion, it has been found that reliability is improved as a result of reducing pattern defects such as disconnection. Thus, the inventors have conceived that the above problems can be solved brilliantly and have reached the present invention.

That is, the present invention is a wiring board having a structure in which a first wiring, an insulating film, and a second wiring are laminated in this order, and the wiring board has a conductive portion in a region facing the second wiring under the insulating film. The insulating film has an opening that exposes the conductive part to the second wiring side, and the second wiring covers the opening of the insulating film and is connected to the conductive part ( Hereinafter also referred to as “first wiring board”. The first wiring is disposed below the insulating film, and the second wiring is disposed on the insulating film. The first wiring and the second wiring are normally arranged so as to have an intersection when viewed in plan, and a short circuit (leakage) is prevented by the insulating film.

The first wiring board has a conductive portion in a region facing the second wiring under the insulating film, the insulating film has an opening that exposes the conductive portion to the second wiring side, and the second wiring Covers the opening of the insulating film and is connected to the conductive portion. Thereby, for example, as shown in FIG. 1A, by using the opening 2a and the conductive portion 3a of the insulating film, the wiring (first layer) arranged on the insulating film without changing the film thickness and width. (2 wiring) Since the cross-sectional area of 1 can be increased, the resistance can be reduced. In addition, the planar area (area when viewed in plan) of the second wiring 1 can be reduced, and the device size can be reduced. Furthermore, since the structure of the second wiring 1 is a laminated structure (such as a two-layer structure), pattern defects such as disconnection can be reduced and reliability can be improved as compared with a single-layer structure.

The conductive portion is disposed in a region facing the second wiring under the insulating film, that is, has a portion that does not overlap with the second wiring as long as it has a portion that overlaps with the second wiring when seen in a plan view. However, it is preferable that all are located within the region of the second wiring. Thereby, when a conductive part consists of material which has light-shielding properties, such as aluminum (Al), the fall of an aperture ratio can be prevented. The number of the conductive portions may be single or plural with respect to the second wiring. The material for the conductive portion is not particularly limited, and examples thereof include conductors such as metals, semiconductors such as silicon (Si) and germanium (Ge), and highly doped impurity semiconductors. The method for forming the conductive part is not particularly limited, and examples thereof include a method of depositing a metal by sputtering (film formation) and then patterning the metal film by dry etching or wet etching.

As long as the opening part of the said insulating film exposes at least one part of a conductive part to the 2nd wiring side, the whole conductive part may be exposed. In addition, when there are a plurality of conductive portions, an opening of one insulating film may expose the plurality of conductive portions on the second wiring side. Furthermore, the number of openings in the insulating film may be single or plural for one conductive portion. The shape of the opening of the insulating film is not particularly limited. For example, the cross-sectional shape is a shape having a flat side surface as shown in FIG. 1A, and the side surface as shown in FIG. A shape having a curved surface, a shape having a convex side surface as shown in FIG.

The material for the insulating film is not particularly limited, and examples thereof include silicon oxide (SiO ₂ ) and silicon nitride (Si ₃ N ₄ etc.). The method for forming the insulating film is not particularly limited, and examples thereof include a plasma chemical vapor deposition (CVD) method and a spin coating method. Examples of the method for forming the opening of the insulating film include a dry etching method and a wet etching method.

The second wiring may cover the entire opening of the insulating film as long as it covers at least a part of the opening of the insulating film. For example, as shown in FIG. 1A, it is preferable that a part of the second wiring runs on the insulating film and covers the opening of the insulating film. According to this, compared with the form in which the wiring 1 as shown in FIG. 3 does not run on the insulating film 2, the plane area and the cross-sectional area of the wiring can be increased, and the resistance of the wiring can be reduced. .

As long as the second wiring is electrically connected to the conductive portion, the second wiring may or may not be in contact with the conductive portion. For example, when the second wiring is made of a conductor and the conductive portion is made of a semiconductor, an alloy layer, a highly doped impurity semiconductor layer, or the like is formed between the second wiring and the conductive portion in order to form an ohmic junction. It may be interposed between them. However, from the viewpoint of simplification of the manufacturing process, the second wiring is preferably in contact with the conductive portion.

The first wiring board of the present invention may or may not have other components as long as the first wiring, the insulating film, the second wiring, and the conductive portion are included as components. There is no particular limitation. In addition, the material of the said 1st wiring and 2nd wiring is not specifically limited, The material etc. which were illustrated by the electroconductive part are mentioned.

The preferable form in the 1st wiring board of this invention is demonstrated in detail below.
The conductive part is preferably made of a material for the first wiring. According to this, since the conductive portion can be formed in the same process as the first wiring, the operational effect of the present invention can be obtained without increasing the number of processes.

A plurality of openings in the insulating film are provided in the width direction of the second wiring, and the second wiring integrally covers the plurality of openings in the insulating film and is connected to the conductive portion. It is preferable. According to this, as shown in FIG. 5, for example, the cross-sectional area of the second wiring 11 can be increased, and as a result, the resistance of the second wiring 11 can be further reduced. The plurality of openings in the insulating film preferably have the same shape and size, and more preferably have the same shape and size arranged in parallel in the width direction.

The first wiring is a scanning line (also referred to as a gate wiring), the second wiring is a data line (also referred to as a source wiring or a signal line), and the conductive portion is made of a material for the scanning line. It is preferable. According to this, it is possible to provide an active matrix substrate or the like that can reduce the resistance of the data line and improve the reliability without reducing the aperture ratio and without increasing the number of steps. In this case, the opening of the insulating film is usually preferably formed in the same process as the process of forming the connection port in the transistor portion.
The scanning line material is preferably a conductor such as metal (high melting point metal), and the data line material is preferably a metal conductor (low resistance metal such as Al). In addition, the first wiring is a data line, the second wiring is a scanning line, and the above-described form made of the material of the data line also has the same effect as the above-described form. Is preferable.

The present invention is also a wiring board having a structure in which a wiring, an insulating film, and a pixel electrode are laminated in this order, wherein the insulating film has an opening that exposes the wiring to a formation surface of the pixel electrode. The board is also a wiring board (hereinafter referred to as a “second wiring board”) having a conductive portion covering the opening of the insulating film and having the wiring connected to the conductive portion. The configuration of the second wiring board of the present invention is the same as that of the first wiring board of FIG. 1A except that the arrangement relationship between the wiring and the conductive portion is reversed, as shown in FIG. The same as 1 wiring board. Therefore, according to the 2nd wiring board of the present invention, the same operation effect as the 1st wiring board of the present invention can be acquired.

The conductive portion may have a portion that does not overlap with the wiring as long as it has a portion that overlaps with the wiring when seen in a plan view, but it is preferable that all of the conductive portions are located in the wiring region. Thereby, when a conductive part consists of material which has light-shielding properties, such as aluminum (Al), the fall of an aperture ratio can be prevented.

The second wiring board of the present invention may or may not have other components as long as the wiring, the insulating film, the pixel electrode, and the conductive portion are included as the components, and particularly limited. Is not to be done. The details of the materials, shapes, suitable forms, etc. of the wiring, insulating film and conductive part are referred to the description of the first wiring board of the present invention. Examples of the material for the pixel electrode include a transparent conductive material such as indium tin oxide (ITO), and a reflective conductive material such as aluminum.

The preferable form in the 2nd wiring board of this invention is demonstrated in detail below.
The conductive part is preferably made of a material for the pixel electrode. According to this, the operation and effect of the present invention can be obtained without increasing the number of steps. In this case, the opening of the insulating film is preferably formed in the same process as a through hole for a contact hole that electrically connects a pixel electrode and a drain electrode of a thin film transistor (TFT).
Note that when the pixel electrode has a plurality of types such as a portion having a single layer structure and a portion having a laminated structure, the conductive portion is preferably made of any one kind of pixel electrode material.

Preferably, the pixel electrode has a structure in which a transparent conductive layer and a reflective conductive layer are stacked, and the conductive portion has a stacked structure of pixel electrodes. As a result, the cross-sectional area of the conductive portion is increased, and as a result, the resistance of the wiring electrically connected thereto can be further reduced. Examples of the material for the transparent conductive layer include indium tin oxide (ITO). Examples of the material of the reflective conductive layer include aluminum (Al).

The wiring is preferably a data line. According to this, the resistance of the data line can be lowered, and the display quality can be improved. The wiring may be a scanning line. According to this, the resistance of the scanning line can be lowered, and the display quality can be improved.

The present invention further provides a wiring board having a structure in which a first wiring, an insulating film, and a second wiring are laminated in this order, and the second wiring has a portion intersecting with the first wiring when viewed in plan. It is also a wiring board (hereinafter also referred to as “third wiring board”) having a width greater than the average width at the intersection. The area where the first wiring is arranged is a dimming or shading area, and usually does not participate in display. Therefore, by increasing the width of the second wiring at the intersection with the first wiring, it is possible to reduce the resistance of the second wiring while suppressing a reduction in the aperture ratio.
The portion larger than the average width of the second wiring may be located in a region that does not overlap with the first wiring as long as it overlaps with the intersection with the first wiring in plan view. . From the viewpoint of the aperture ratio, it is preferable that a portion larger than the average width of the second wiring is located in an intersection with the first wiring.

Preferably, the first wiring is a scanning line, and the second wiring is a data line. The scanning line and the data line are usually arranged so as to have an intersection when viewed in plan. With respect to the data line, by making the width at the intersecting portion larger than the average width, it is possible to reduce the resistance of the data line while suppressing the reduction of the aperture ratio.

The first wiring may be a storage capacitor (Cs) wiring, and the second wiring may be a data line. The Cs wiring and the data line are usually arranged so as to have an intersection when viewed in plan. With respect to the data line, by making the width at the intersecting portion larger than the average width, it is possible to reduce the resistance of the data line while suppressing the reduction of the aperture ratio.

The first wiring board, the second wiring board, or the third wiring board is preferably an active matrix substrate. Since the first wiring board, the second wiring board, and the third wiring board of the present invention can reduce the resistance of the data line and the like and improve the reliability without reducing the aperture ratio, the high reliability can be achieved. And an active matrix substrate suitable for a liquid crystal display device or the like can be provided.

The present invention is also a liquid crystal display device including the first wiring board, the second wiring board, or the third wiring board. Since the first wiring board, the second wiring board, and the third wiring board of the present invention can reduce the resistance of data lines and the like and improve the reliability without reducing the aperture ratio, A high-quality liquid crystal display device can be provided.

According to the wiring board of the present invention, the resistance of the wiring can be reduced without changing the film thickness and width, and pattern defects such as disconnection can be reduced, resulting in improved reliability. it can.

Hereinafter, the present invention will be described in more detail with reference to embodiments, but the present invention is not limited only to these embodiments.

(Embodiment 1)
FIG. 4 is a schematic cross-sectional view showing the configuration of the active matrix substrate (wiring board) according to Embodiment 1 of the present invention.
In the present embodiment, as shown in FIG. 4, the interlayer insulating film 12 under the source electrode wiring (second wiring) 11 is removed, and the conductive film formed in the same process as the gate electrode wiring (first wiring). It is directly connected to the portion 13a. Thereby, since the cross-sectional area of the source electrode wiring 11 becomes large, it is possible to reduce the wiring resistance without changing the film thickness, the width, and the number of processes.

As the structure of the source electrode wiring 11, titanium (Ti) layer / aluminum (Al) layer / Ti layer (a structure in which an Al layer is sandwiched between Ti layers; the Ti layer functions as a barrier layer) can be mentioned. . An example of the material for the conductive portion 13a and the gate electrode wiring is tungsten (W). Further, examples of the material of the interlayer insulating film 12 include a silicon oxide (SiO ₂ ) film or a laminated film of a SiO ₂ film and a SiN _X film.

(Embodiment 2)
FIG. 5 is a schematic cross-sectional view showing a configuration of an active matrix substrate (wiring board) according to Embodiment 2 of the present invention.
In the present embodiment, as shown in FIG. 5, the interlayer insulating film 12 is made uneven with respect to the first embodiment. That is, a plurality of openings 12 a of the interlayer insulating film 12 are provided in the width direction of the source electrode wiring (second wiring) 11. Thereby, since the cross-sectional area of the source electrode wiring 11 becomes larger, it is possible to make the wiring resistance smaller without changing the film thickness, width, and number of steps.

(Embodiment 3)
FIG. 6 is a schematic cross-sectional view showing a configuration of an active matrix substrate (wiring board) according to Embodiment 3 of the present invention.
In the present embodiment, as shown in FIG. 6, after the interlayer insulating film 14 on the source electrode wiring (wiring) 11b is removed, the wiring (transparent conductive layer) 15a made of indium tin oxide (ITO) is formed together with the pixel electrode. And wiring (reflective conductive layer) 15b made of aluminum (Al) is formed. Accordingly, the cross-sectional area of the source electrode wiring 11b can be increased without changing the film thickness, width, and number of steps, and thus the wiring resistance can be reduced.

(Embodiment 4)
FIG. 7 is a schematic plan view showing a configuration of an active matrix substrate (wiring board) according to Embodiment 4 of the present invention. FIGS. 8A to 8C are cross-sectional schematic views taken along lines A1-A2, B1-B2, and C1-C2 in FIG. 7, respectively.
In the present embodiment, the following configuration is adopted in order to reduce the resistance of each of the source electrode wiring 11 and the gate electrode wiring 13. That is, in order to reduce the resistance of the source electrode wiring 11, as shown in FIG. 8A, the conductive portion 13a formed in the same process as the gate electrode wiring (first wiring) 13 is replaced with the source electrode wiring (second wiring). ) 11, the interlayer insulating film 14 between the source electrode wiring 11 and the conductive portion 13 a is removed and directly connected to increase the cross-sectional area of the source electrode wiring 11. Further, in order to lower the resistance of the gate electrode wiring (wiring) 13, the interlayer insulating film 14 on the gate electrode wiring 13 is removed and formed in the same process as the source electrode wiring 11 as shown in FIG. 8B. By directly connecting to the conductive portion 11a, the cross-sectional area of the gate electrode wiring is increased. Further, as shown in FIG. 8C, at the intersection of the source electrode wiring 11 and the gate electrode wiring 13, the pattern width is increased to reduce the wiring resistance.
Thereby, the resistance of the wiring can be reduced and the reliability can be improved without changing the film thickness, the width, and the number of steps.

(A) is a cross-sectional schematic diagram which shows one structure of the 1st wiring board of this invention, (b) is a cross-sectional schematic diagram which shows one structure of the 2nd wiring board of this invention. (A) And (b) is a cross-sectional schematic diagram which respectively shows one structure of the 1st wiring board of this invention. It is a cross-sectional schematic diagram which shows one structure of the 1st wiring board of this invention. It is a schematic diagram which shows the cross-sectional shape of the width direction of the source electrode wiring (2nd wiring) etc. which were provided in the active matrix substrate (wiring board) which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the cross-sectional shape of the width direction, such as a source electrode wiring (2nd wiring) provided in the active matrix substrate (wiring board) which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the cross-sectional shape of the width direction, such as a source electrode wiring (2nd wiring) provided in the active matrix substrate (wiring board) which concerns on Embodiment 3 of this invention. It is a plane schematic diagram which shows the structure of the active matrix substrate (wiring board) which concerns on Embodiment 4 of this invention. (A)-(c) is a cross-sectional schematic diagram in the A1-A2 line | wire, B1-B2 line | wire, and C1-C2 line | wire of FIG. 7, respectively.

Explanation of symbols

0: substrate 1: second wiring 1a: wiring 2: insulating film 2a: insulating film opening 3a: conductive portion 10: glass substrate 11: source electrode wiring (second wiring)
11a, 13a, 15: conductive portion 11b: source electrode wiring (wiring)
12, 14: Interlayer insulating film (insulating film)
12a, 14a: Opening (insulating film opening)
13: Gate electrode wiring (first wiring, wiring)
15a: Wiring made of a transparent conductive material (transparent conductive layer)
15b: wiring made of a reflective conductive material (reflective conductive layer)

Claims (12)

A wiring board having a structure in which a first wiring, an insulating film, and a second wiring are laminated in this order,
The wiring board has a conductive portion in a region facing the second wiring under the insulating film,
The insulating film has an opening that exposes the conductive portion to the second wiring side,
The wiring board, wherein the second wiring covers the opening of the insulating film and is connected to the conductive part. The wiring board according to claim 1, wherein the conductive portion is made of a material of the first wiring. A plurality of openings in the insulating film are provided in the width direction of the second wiring,
The wiring board according to claim 1, wherein the second wiring integrally covers a plurality of openings of the insulating film and is connected to the conductive portion. The first wiring is a scanning line;
The second wiring is a data line;
4. The wiring board according to claim 2, wherein the conductive portion is made of a scanning line material. A wiring board having a structure in which wirings, insulating films and pixel electrodes are laminated in this order,
The insulating film has an opening that exposes the wiring on the formation surface of the pixel electrode,
The wiring board further includes a conductive portion that covers the opening of the insulating film, and the wiring is connected to the conductive portion. The wiring board according to claim 5, wherein the conductive portion is made of a material for a pixel electrode. The pixel electrode has a structure in which a transparent conductive layer and a reflective conductive layer are laminated,
The wiring board according to claim 6, wherein the conductive portion has a laminated structure of pixel electrodes. The wiring board according to claim 5, wherein the wiring is a data line. A wiring board having a structure in which a first wiring, an insulating film, and a second wiring are laminated in this order,
The wiring board, wherein the second wiring has a portion intersecting with the first wiring when viewed in plan, and a width at the intersecting portion is larger than an average width. The first wiring is a scanning line;
The wiring board according to claim 9, wherein the second wiring is a data line. The wiring board according to claim 1, wherein the wiring board is an active matrix substrate. A liquid crystal display device comprising the wiring board according to claim 1.

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