JP2000019554A - Cog type liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element free from the degradation in the adhesion property of films and film peeling which occur in the case lead parts laminated with picture element wiring electrodes by ITO films are drawn out between both gate and source electrodes consisting of the tantalum films of power source lead parts of gate COG(clip-on-glass). SOLUTION: Gate wiring 2 is formed by patterning the tantalum film deposited on a glass substrate 1 and thereafter, a TaOx film is formed in the surface layer part by anodic oxidation and SiNx is formed as a gate insulating film 4. The insulating film is removed only from the input and output parts of the power source lead parts of the gate COG and the insulating film is made to remain in other parts. The transparent electrode material ITO and tantalum constituting the picture element electrodes 8 are deposited and are then patterned to form the source and drain electrode wiring 10. The overlap width of the gate tantalum film, picture element ITO film and source tantalum film constituting a contact is confined to <=100 μm. The good adhesion property of the lead parts is obtd. by the insulating films made to remain. A protective film is formed on the upper layer, by which a TFT-LCD matrix substrate is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an active matrix type liquid crystal display device, and more particularly, to a TFT (Thin F) as a switching device for selectively driving a pixel electrode.
The present invention relates to a liquid crystal display device using an ilm transistor, an MIM device, a MOS transistor device, a diode, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As an example of a matrix electrode substrate of a liquid crystal display device, a conventional TFT-LCD (Liquid Crystal) is used.
FIG. 4 shows a cross-sectional view of the TFT portion of the active matrix substrate for Display). TFT shown in FIG.
The structure of the substrate is described below together with the manufacturing procedure. A glass substrate 1 is used as an insulating substrate, and a tantalum thin film is formed thereon by sputtering and patterned to form a gate wiring (electrode) 2. Thereafter, anodizing treatment is performed with an ammonium tartrate solution as an electrolytic solution, and Ta is applied to the surface layer.
An Ox film 3 is formed.

After that, SiNx is formed as a gate insulating film 4 covering the gate wiring 2, and an intrinsic amorphous Si semiconductor is formed as a semiconductor layer 5 on the gate insulating film 4. Next, n + type semiconductor layers 6 and 7 are formed of amorphous Si doped with n + to form the source and drain portions of the TFT. Further, the n + type semiconductor layer 6,
7, a picture element electrode and a source / drain electrode wiring 10,
The ITO (Indi) of the transparent conductive films 8 and 9
um Tin Oxide) A thin film wiring is formed, and a source
Drain electrode wirings 10 and 11 are formed. The upper layer is covered with a protective film (not shown).

In this case, the laminated state of the terminal portions is such that a gate wiring 2 of a tantalum thin film is formed on an upper layer of a glass substrate 1, a TaOx film 3 as an anodic oxide film 3 which has been subjected to anodizing treatment, and a gate insulating film 4 A source / drain electrode wiring 10 composed of an ITO thin film 8 and a tantalum thin film is formed on this SiNx film, and the upper layer is covered with a protective film. Among them, the gate COG (Clip O
As shown in FIG. 3, the structure of the power supply lead portion of the n-glass) is as follows: a tantalum thin-film gate wire 2, an ITO thin film 8, a source / drain electrode wire 10,
It is in a state covered with a protective film. This is because, in order to minimize the delay of the lead portion, the TaOx film 3 subjected to the anodic oxidation treatment of the entire gate tantalum thin film 2 of the lead portion and the SiNx film as the gate insulating film 4 are removed. Tantalum thin film source / drain electrode wiring 10
Is formed in the upper layer, and the contact area between the gate and the source is maximized to reduce the contact resistance.

[0005]

In the matrix electrode substrate having the structure as described in the prior art, in the power supply lead portion of the gate COG, an ITO film serving as a pixel electrode and a tantalum film are formed directly on the ITO film on the gate electrode. Source by thin film
Since the drain electrode wiring is laminated, the portion of the ITO film / tantalum film comes off. This is due to the relationship between the tantalum film of the gate wiring and the ITO film of the picture element electrode. The tantalum film easily takes in oxygen of the ITO film, and once oxygen is taken in, the expansion coefficient increases. Besides, ITO
When a tantalum film as a source electrode wiring is formed on the film, the source film becomes susceptible to the film stress of the source film, and
The compatibility between the TO film and the tantalum film deteriorates. That is, the adhesion becomes poor. Further, in this part, the surface of the tantalum film is damaged by dry etching due to etching during dry etching of the gate insulating film. Therefore, the above elements overlap, and the adhesion of the film at this portion is reduced, which is a major cause of film peeling.

The present invention relates to a gate COG according to the prior art.
In the power supply lead portion, a lead portion in which a picture element wiring electrode exemplified by an ITO film is laminated between both electrodes of a gate wiring electrode and a source wiring electrode each constituted by an electrode exemplified by a tantalum film is drawn out. It is an object of the present invention to provide a liquid crystal display element in which the adhesion of the film is not reduced and the film is not peeled off at the power supply lead portion of the gate COG.

[0007]

In order to solve the above-mentioned problems, in a power supply lead portion of a gate COG, only a tantalum thin film of a gate wiring is subjected to anodization on a tantalum thin film of a gate wiring only in an input portion and an output portion of a lead wire. And the gate insulating film S
The iNx film is removed without leaving it so as to have a necessary function as a power supply lead, and the other leads are connected to the T lead.
The aOx film and the SiNx film are left without being removed, and the anodized TaOx film left on the gate film, the SiNx film as the gate insulating film, and the ITO film and the source film are laminated thereon. Due to the formation, the adhesion of the film is improved as compared with the related art, the film is not peeled off, and the defect occurrence rate in this portion can be reduced without affecting the display quality.

Each of the claimed inventions constitutes the following technical means. The invention according to claim 1, wherein the gate electrode wiring and the source electrode wiring each having electrodes arranged in a matrix according to display picture elements on a transparent insulating substrate and wiring connecting the electrodes, the gate electrode and the gate electrode, In a COG type liquid crystal display element in which a switching element and a picture element electrode selectively driven by the switching element are arranged in each area surrounded by the source electrode, and a voltage applied to a liquid crystal is controlled by the picture element electrode, To connect power supply to gate C
On the gate electrode wiring in the input part and the output part of the OG power supply lead, the picture element electrode is directly laminated except for an insulating film formed on the gate electrode as required for the switching operation, and the gate COG power supply lead is provided. The other lead portions of the input section and the output section are characterized by leaving the insulating film.

According to a second aspect of the present invention, in the first aspect, when the input portion and the output portion of the gate COG power supply lead are provided at the edge of the electrode wiring, the gate C
The width of a contact portion formed by directly laminating the picture element electrodes as an input portion and an output portion of an OG power supply lead wire is set to 100 μm or less.

According to a third aspect of the present invention, in the first aspect, when the input portion and the output portion of the gate COG power supply lead line are provided at an intermediate portion up to the edge portion of the electrode wiring, The width of a contact portion formed by directly laminating the picture element electrodes as an input portion and an output portion of a power supply lead wire is set to 100 to 300 μm.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a liquid crystal display device according to the present invention will be described below with reference to the accompanying drawings. (Embodiment 1) First, a basic embodiment of the present invention will be described below. 1 and 2 show a cross section of a structure of a power supply lead portion of a gate COG in an example in which a liquid crystal display element according to the present invention is implemented on a matrix substrate for a TFT-LCD. The structure shown in FIGS. 1 and 2 is described below together with the manufacturing procedure. As shown in FIGS. 1 and 2, a gate tantalum thin film is formed on a glass substrate 1 by sputtering, and a patterning process is performed on the film to form a gate wiring 2. Thereafter, an anodic oxidation process is performed with an ammonium tartrate solution as an electrolytic solution to form a TaOx film as an anodic oxide film on a surface layer portion, and then a SiNx film as a gate insulating film 4.

At this time, only the portion used as the input portion and the output portion of the power supply lead portion of the gate COG is removed except for the insulating film.
Other lead portions have a structure in which the insulating film 4 is left. Next, a transparent conductive material ITO serving as the pixel electrode 8 is formed into a film by sputtering, and is patterned by photolithography. Next, a tantalum film is patterned thereon by photolithography to form a source / drain electrode wiring 10.
To form Thereafter, the layers are sequentially laminated so as to form a protective film, and a TFT-LCD matrix substrate is manufactured.

(Embodiment 2) An embodiment taking into account the means employed when embodying Embodiment 1 as a liquid crystal display element according to the present invention will be described below. FIG. 1 is a sectional view showing a structure of a power supply lead portion of a gate COG according to the present embodiment implemented on a matrix substrate for a TFT-LCD. The structure shown in FIG. 1 is described below together with its manufacturing procedure. As shown in FIG. 1, a tantalum thin film to be used as a gate is formed on a glass substrate 1 by sputtering, and this film is patterned to form a gate wiring 2. Thereafter, anodizing treatment was performed with an ammonium tartrate solution as an electrolytic solution, and Ta was applied to the surface layer.
An Ox film is formed, and then SiNx is formed as a gate insulating film 4. At this time, only the portions used as the input portion and the output portion of the power supply lead portion of the gate COG are removed except for the insulating film, and the other lead portions have the structure in which the insulating film 4 remains. next,
A transparent conductive material ITO serving as the picture element electrode 8 is formed by sputtering and patterned by photolithography. Then, a tantalum film is patterned thereon by photolithography. The tantalum film is patterned by photolithography to form the source / drain electrode wiring 10. Here, in order to make contact with the tantalum thin film of the gate wiring electrode, the ITO film of the picture element wiring electrode, and the tantalum thin film of the source wiring electrode, the gate, the picture element,
The overlap width of each film of the source wiring electrode needs to be 100 μm or less. By doing so, good adhesion of the film aimed at by the present invention can be obtained. It should be noted that this overlap width has a value of about 100 μm because there is a slight difference in the numerical value adopted depending on the model. After layering in this manner, a protective film is formed thereon to form a TFT-
An LCD matrix substrate is manufactured.

(Embodiment 3) Another embodiment taking into account the means employed in embodying Embodiment 1 as a liquid crystal display device according to the present invention will be described below. FIG. 2 is a cross-sectional view showing the structure of the power supply lead portion of the gate COG according to the present embodiment implemented on a matrix substrate for a TFT-LCD. The structure shown in FIG. 2 is described below together with its manufacturing procedure. As shown in FIG. 2, a tantalum thin film to be used as a gate is formed on a glass substrate 1 by sputtering, and this film is patterned to form a gate wiring 2. Thereafter, an anodic oxidation treatment is performed with an ammonium tartrate solution as an electrolytic solution to form a TaOx film on the surface layer portion.
Form Nx. At this time, only the portions used as the input portion and the output portion of the power supply lead portion of the gate COG are removed except for the insulating film, and the other lead portions have the structure in which the insulating film 4 remains.
Next, a transparent conductive material ITO that becomes the pixel electrode 8 is formed into a film by sputtering, and is patterned by photolithography. Then, a tantalum film is patterned thereon by photolithography. The tantalum film is patterned by photolithography to form the source / drain electrode wiring 10. Here, the gate wiring electrode 2
In order to make contact with the tantalum thin film of FIG. 1, the ITO film of the picture element wiring electrode 8, and the tantalum thin film of the source wiring electrode 10,
Although it is necessary to provide an overlap of each film of the gate, picture element and source wiring electrodes, this is not an edge portion as in the second embodiment, but is provided in the middle as shown in FIG.
In the edge portion at the end of the overlap, a threshold is provided by the gate insulating film 4 below the source and picture element wiring electrodes. By doing so, the good film adhesion intended by the present invention can be achieved. After the layering is performed in this manner, a TFT-LCD matrix substrate is manufactured by forming a protective film thereon.

[0015]

According to the COG type liquid crystal display device of the first aspect of the invention, the film adhesion is improved by leaving the insulating film on the gate thin film other than the contact portion in the power lead portion of the gate COG. In the conventional method, the tantalum thin film forming the gate electrode wiring
Peeling of the TO film / source film is reduced.

According to the COG type liquid crystal display element of the present invention, in the input / output portion of the lead wire of the power supply lead portion of the gate COG, the above-mentioned contact portion excluding the insulating film is a gate thin film and an ITO film / source. By adopting a structure in which the overlapping width of the films is 100 μm or less, film stress is hardly applied, and film peeling is further reduced.

According to the third aspect of the present invention, the overlap width of the gate thin film and the ITO film / source film is set to 100 to 300 μm in order to increase the contact portion in the structure of the first aspect of the present invention. In addition, by providing this in the middle part up to the edge and leaving the gate insulating film under the edge part of the source and providing a threshold by the gate insulating film, a large contact area can be obtained in the contact part, and the contact resistance Can be reduced, so that film peeling can be reduced and the contact resistance can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a power supply lead portion of a gate COG of an embodiment of a COG liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view showing a structure of a power lead portion of a gate COG in another embodiment of the COG liquid crystal display element according to the present invention.

FIG. 3 is a cross-sectional view showing a structure of a power supply lead portion of a conventional gate COG.

FIG. 4 is a sectional view showing a main part of a structure of a conventional example of the liquid crystal display element.

[Explanation of symbols]

1 ... glass substrate, 2 ... tantalum thin film of gate wiring electrode,
3 anodic oxide film, 4 gate insulating film, 5 amorphous silicon semiconductor layer, 6, 7 n + semiconductor layer, 8, 9 transparent conductive film (ITO film), 10, 11 source / drain electrode wiring.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Okamoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Yukiya Nishioka 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F term in reference (reference) 2H092 GA41 GA42 JA36 JB24 JB26 JB33 JB57 KA12 KA18 KB04 MA05 MA24 NA18 NA28

Claims (3)

[Claims] 1. A gate electrode line and a source electrode line each having electrodes arranged in a matrix on a transparent insulating substrate according to display picture elements, and lines connecting the electrodes, and the gate electrode and the source electrode. In a COG type liquid crystal display element in which a switching element and a picture element electrode selectively driven by the switching element are arranged in each of the areas surrounded by a circle and a voltage applied to a liquid crystal is controlled by the picture element electrode, a power supply On the gate electrode wiring at the input and output of the gate COG power lead connected to
Except for the insulating film formed on the gate electrode as required for the switching operation, the picture element electrodes are directly laminated, and the other lead portions of the input part and the output part of the gate COG power supply lead line are made of the insulating film. CO characterized by leaving
G-type liquid crystal display element. 2. The COG type liquid crystal display element according to claim 1, wherein an input portion and an output portion of said gate COG power supply lead are provided at an edge portion of said electrode wiring, and said input portion of said gate COG power supply lead is provided. And a width of a contact portion formed by directly laminating the picture element electrode as an output portion is 100 μm or less. 3. The COG type liquid crystal display element according to claim 1, wherein the input part and the output part of the gate COG power supply lead line are provided at an intermediate portion up to an edge portion of the electrode wiring. A COG type liquid crystal display device, wherein a width of a contact portion formed by directly laminating the picture element electrodes as an input portion and an output portion of a power supply lead wire is set to 100 to 300 μm.