JPH09265115A - Active matrix type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix type display device with which the degradation in the production yield occurring in the disconnection defect of data buses is sufficiently suppressed. SOLUTION: This display device has plural data buses 111 arranged on an insulating substrate 101, plural pixel electrodes 191 arranged along the data buses 111 and a first electrode substrate 100 including the upper electrodes 123, 129 and lower electrodes 127 having the regions overlapping on each other via dielectric layers and having two-terminal nonlinear elements 121 connecting the data buses 111 and pixel electrodes 191. The lower electrodes 127 are constituted by patterning the wirings for the striped lower electrodes and the data buses 111 are arranged to part from the regions 103a, 103b where the wirings for the lower electrodes exit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type display device using a two-terminal non-linear element such as a MIM (Metal Insulator Metal) element as a switch element.

[0002]

2. Description of the Related Art MI is used as a switching element for each display pixel.
An active matrix type display device using a two-terminal nonlinear element such as an M element, a MIS element or a SiNx element has a high definition equivalent to that of an active matrix type display device including a three-terminal nonlinear element such as a thin film transistor as a switch element. Since it is capable of displaying, has a small number of manufacturing steps, and can be manufactured at low cost and with high manufacturing yield, it is used for displaying on a television or for displaying on a word processor, a personal computer, or the like.

A general active matrix type liquid crystal display device using an MIM element as a two-terminal nonlinear element will be briefly described with reference to FIG. This liquid crystal display device (1) comprises a pair of electrode substrates (500) and (700), and a liquid crystal material (800) held between the pair of electrode substrates (500) and (700) via an alignment film. One of the electrode substrates (500) is, for example, as shown in FIG. 3, a plurality of data buses (511) wired substantially parallel to each other,
Pixel electrodes (591) arranged between (511), pixel electrodes
MIM for electrically connecting the (591) and the data bus (511)
Includes a helix (521). Also, the other electrode substrate (700)
Includes a plurality of rows of stripe-shaped counter electrodes (711) corresponding to a group of pixel electrodes (591) in each row.

By the way, the MIM element (521) intersects with the first upper electrode (523) led from the data bus (511) and the first upper electrode (523) through an insulating film (not shown). The lower electrode (527) includes a second upper electrode (529) disposed on the lower electrode (527) through an insulating film and electrically connected to the pixel electrode (591). As a result, the MIM element (521) includes the first MIM element composed of the first upper electrode (523) / insulating film / lower electrode (527) and the lower MIM element (527) / insulating film / second upper electrode (529). ) And a second MIM element composed of

[0005]

The above-mentioned M
Since the lower electrode (527) is anodized in the insulating film that constitutes the IM element (521), it is necessary to apply a desired voltage to the lower electrode (527) outside the display area during the process of forming the insulating film. The wiring for the lower electrode is drawn out to the side.

However, according to the above-described conventional structure, a disconnection defect occurs in the vicinity (505) of the area where the data bus (111) intersects the areas (503a), (503b) where the lower electrode wiring was formed. There is. In particular, in recent years, attempts have been made to reduce the wiring width of the data bus (111) in response to the demand for a high aperture ratio, and thus the above-mentioned disconnection failure becomes remarkable.

The present invention has been made in response to such a technical problem, and provides an active matrix type display device in which a decrease in manufacturing yield due to disconnection of a data bus is sufficiently suppressed. It is an object.

[0008]

According to a first aspect of the present invention, a plurality of data buses arranged on an insulating substrate, a plurality of pixel electrodes arranged along the data buses, and a dielectric layer are provided. A first electrode substrate provided with a two-terminal non-linear element for connecting the data bus and the pixel electrode, the first electrode substrate being opposed to the pixel electrode, the first electrode substrate including an upper electrode and a lower electrode arranged to have an overlapping region with each other. In an active matrix type display device comprising a second electrode substrate including a counter electrode and a light modulation layer sandwiched between the first electrode and the second electrode, the lower electrode is for a striped lower electrode. It is characterized in that the wiring is patterned, and the data bus is separated from the region where the lower electrode wiring was present.

The invention described in claim 2 is the active matrix type display device according to claim 1, wherein the dielectric layer is formed by anodizing the wiring for the lower electrode.

As a result of sincere research by the present inventors, an undesired step difference of about 700 to 1000 angstroms is formed in the vicinity of the interface between the region where the lower electrode wiring was formed on the substrate and the other region. It has been found that this causes a disconnection defect in the data bus.

According to the active matrix type display device of the present invention, as described above, the data bus is arranged apart from the region where the lower electrode wiring was present, so that the area where the lower electrode wiring was formed is The influence of an undesired step difference that occurs in the vicinity of the interface with other regions can be eliminated, and a high manufacturing yield can be secured.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A light transmissive active matrix type liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the active matrix type liquid crystal display device (1) of this embodiment has a structure in which each substrate (100), (30) is provided between an array substrate (100) and a counter substrate (300).
0) The nematic liquid crystal (400) is twisted and sandwiched between the substrates (100) and (300) by about 90 ° via an alignment film (not shown) arranged on the main surface, and the polarization axes are orthogonal to each other. The polarizing plates (431) and (441) are attached to the outer surfaces of the substrates (100) and (300).

The array substrate (100) is a transparent glass substrate (10
1) A plurality of substantially parallel data buses (111) having a wiring width of 5 μm are arranged on the top in a column direction. The data bus (111) is formed by patterning a titanium (Ti) film having a thickness of 1500 Å by photolithography. A pixel electrode (19) made of ITO (Indium Tin Oxide) is provided between each data bus (111).
1) are arranged. The data bus (111) and the pixel electrode (191) are electrically connected via the MIM element (121).

The data bus (111) preferably has a wiring width of 10 μm or less in order to increase the aperture ratio. In order to prevent disconnection and achieve low resistance, the IT which constitutes the pixel electrode (191).
A laminated structure with an O film or the like may be used. Although titanium (Ti) is used as the wiring material here, other than this, chromium (Cr), tantalum (Ta), aluminum (Al), or the like is used.

The counter substrate (300) is a transparent glass substrate (30
1) In the row direction that is approximately orthogonal to the data bus (111), IT
A plurality of stripe-shaped counter electrodes (311) made of O are arranged. In order to realize color display, a color filter may be arranged between the glass substrate (301) and the counter electrode (311).

By the way, each MIM element (12
1) includes first and second MIM elements connected in series. Specifically, each MIM element (121) is a data bus (111)
A first upper electrode (123) extending from the first upper electrode (12)
3) and the first upper electrode (123) are anodized, and the lower electrode (127) and the lower electrode (127) and the first upper electrode (123) which are orthogonal to each other through an insulating film (not shown) are anodized. A second upper electrode (129) which is orthogonal to the pixel electrode (191) through an insulating film is formed and is connected to the pixel electrode (191). In this example, the bottom electrode (127)
Was made of a tantalum (Ta) film having a thickness of 1500 angstroms.
l) etc. are used.

As a result, the first MIM element is composed of the first upper electrode (123) / insulating film / lower electrode (127), and the first MIM element is further composed of the lower electrode (127) / insulating film / second upper electrode (129). A second MIM element connected in series with the element is configured.

The MIM element (121) is connected to the first MIM element and the second MIM element.
This is because the series connection structure with the MIM element compensates for the asymmetry of the element characteristics in the positive and negative polarities, and thereby a good display image can be obtained.

By the way, in this embodiment, the lower electrode (12
7) Since it is necessary to dispose an insulating film made of an anodic oxide film on the upper electrode, the wiring for the lower electrode (128) led out to the desired voltage is applied to the lower electrode (127) during the insulating film formation process. (See FIG. 2). The above-mentioned data bus (111) should not intersect with the regions (103a), (103b) (see FIG. 2) where the lower electrode wiring (128) was present, and should not have an overlapping region. Lower electrode wiring (12
It is placed almost parallel to 8).

As a result, the regions (103a), (103) where the lower electrode wiring (128) existed on the transparent glass substrate (101).
Although there is an undesired step difference of about 1000 angstroms at the interface between b) and another region, the data bus (111) will not be disconnected due to this step difference. Here, in order to achieve a high aperture ratio, the data bus
Even though the wiring width of (111) was set to 5 μm, the reduction in manufacturing yield due to the disconnection of the data bus (111) could be sufficiently suppressed.

Next, a method of manufacturing the active matrix type liquid crystal display device (1) of this embodiment will be described with reference to FIG. First, on a transparent glass substrate (101), using a magnetron batter in an argon (Ar) atmosphere,
A 1500 Angstrom thick tantalum (Ta) film was deposited. Then, as shown in FIG. 2A, patterning is performed in stripes to form stripe-shaped lower electrode wirings (128) for the lower electrodes (127) of the MIM element (121) shown in FIG.
To form

After that, the lower electrode wiring (128) is used as an anode to perform anodic oxidation, as shown in FIG.
An anodic oxide film (124) made of tantalum oxide (TaOx) having an angstrom thickness was formed. In this anodizing treatment, an aqueous solution of citric acid was used as the chemical conversion liquid, and the liquid temperature was 2
5 ° C.

Then, as shown in FIG. 2 (c), the lower electrode wiring (128) and the anodic oxide film (124) are partially removed to form the lower electrode (127) and the MIM element (121). An insulating film (123) made of an anodized film was formed. The lower electrode
With the formation of (127) and the insulating film (123), the areas (103a, 103b) where the lower electrode wiring (128) was present on the substrate and the other areas were exposed to the etching solution or the like. Due to the difference, etc., a step difference of about 1000 angstrom is formed.

After that, a titanium (Ti) film having a thickness of 1500 Å was deposited by a magnetron batter in an argon (Ar) atmosphere. Then, by patterning the titanium (Ti) film, as shown in FIG. 2 (d), a plurality of data buses (111) are extended from the data buses (111) and an insulating film (125) is interposed therebetween. A first upper electrode (123) traversing the lower electrode (127) and a second upper electrode (12) disposed substantially parallel to the first upper electrode (123) and traversing the lower electrode (127).
9) is molded at the same time. At this time, the data bus (111) is
Within the display area, intersect the areas (103a), (103b) where the lower electrode wiring (128) existed, and even in parallel with the lower electrode wiring (128) so that there is no overlapping area. It is arranged.

Argon (Ar) and oxygen (O2)
A 1000 angstrom thick ITO film was deposited by a magnetron batter in the atmosphere. Then, the ITO film was patterned to form a pixel electrode (191) electrically connected to the second upper electrode (129).

After that, the active matrix type liquid crystal display device (1) is completed by a conventional method. As described above, according to this embodiment, the lower electrode wiring (128)
The areas (103a), (103b) where the lower electrode wiring (128) existed are separated from each other so that the areas (103a), (103b) and the data bus (111) are not separated from each other. (Ten
Data bus due to undesired steps formed near 3b)
(111) never breaks. In addition, MIM element (1
21), the first and second upper electrodes (123), (129) are both regions (103a) where the lower electrode wiring (128) is present,
Since they are separated so as not to have a region overlapping with (103b), no device failure is caused. Moreover, according to this embodiment, the manufacturing yield can be improved without increasing the manufacturing process.

[0027]

According to the active matrix type display device of the present invention, since the data bus is arranged apart from the area where the lower electrode wiring was present, the area where the lower electrode wiring was formed and other areas were formed. The influence of an undesired step difference near the interface with the region can be eliminated, and a high manufacturing yield can be secured.

[Brief description of drawings]

FIG. 1 is a partial schematic perspective view of an active matrix type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a partial schematic perspective view for explaining the manufacturing process of the active matrix type liquid crystal display device of FIG.

FIG. 3 is a partial schematic perspective view of a conventional active matrix type liquid crystal display device.

[Explanation of symbols]

 (1)… Active matrix liquid crystal display device (100)… Array substrate (111)… Data bus (121)… MIM element (128)… Lower electrode wiring (300)… Counter substrate

Claims (2)

[Claims] 1. A plurality of data buses arranged on an insulating substrate, a plurality of pixel electrodes arranged along the data buses, and an upper electrode arranged so as to have an overlapping region with each other via a dielectric layer. A first electrode substrate including a two-terminal non-linear element including a lower electrode and connecting the data bus and the pixel electrode; a second electrode substrate including a counter electrode facing the pixel electrode; In an active matrix display device including a light modulation layer sandwiched between the second electrode and the second electrode, the lower electrode is formed by patterning stripe-shaped lower electrode wiring, and the data bus is used for the lower electrode. An active matrix type display device characterized in that it is separated from a region where wiring is present. 2. The active matrix display device according to claim 1, wherein the dielectric layer is formed by anodizing the wiring for the lower electrode.