JPS61250676A - Manufacture of liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method of manufacturing a liquid crystal display device, and particularly to a method of manufacturing a liquid crystal display device, which has a highly simplified manufacturing process and uses a nonlinear element to apply charge to each pixel electrode. The present invention relates to a liquid crystal display device that performs display by storing and holding data.

[Background of the invention]

Although liquid crystal display devices have the advantage of being able to be driven at low voltage and having low power consumption, they have the disadvantage of being able to display only a small amount of information. To solve this problem, it has been considered to connect active elements or nonlinear elements such as thin film transistors (TPT) and metal-insulator-metal (MIM) structures to each pixel.

As shown in FIG. 7, an MIM element is a device in which an insulating thin film 21 is formed between a lower metal layer 19 and an upper metal layer 20 on a substrate 22, and an insulating thin film 21 is formed between a lower metal layer 19 and an upper metal layer 20 on a substrate 22. 8th
It is a nonlinear element that also has voltage/current characteristics as shown in the figure.

This MIM*child operates as follows. However, when a low voltage is applied between the upper and lower metal layers, the VIM element has a high resistance, so if you treat the MIM element as a switch, the switch will be in an open state. Equivalent to. On the other hand, when a high voltage is applied between the upper and lower metal layers 19 and 20, this MIM element exhibits low resistance, which corresponds to a state in which the switch is closed.

When this MIM element is connected to each pixel, each pixel is essentially separated from the signal line.9) The number of pixels in the liquid crystal display device can be greatly increased, increasing the amount of displayed information. .

MIM elements are said to be relatively easy to produce large substrates because the manufacturing process is simpler than that of other elements such as TPT. However, until the completion of the MIM element side substrate, K requires the formation of the lower metal layer, the formation of the insulating thin film, the formation of the upper metal layer,
In particular, the formation of insulating thin films involves processes such as the formation of display electrodes, alignment film formation, and alignment treatment, and involves methods such as anodic oxidation of the lower metal layer, which is a complicated process. It becomes.

Regarding the simplification of the manufacturing process of MIM elements, see Japanese Patent Application Laid-open No. 58
There is No.-127985.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a liquid crystal display device that has a simpler manufacturing process than that of nonlinear element formation.

[Summary of the invention]

The feature of the present invention is that row or column side electrodes are formed on a transparent substrate, display electrodes are formed thereon so as to partially overlap with each other, and a p-overlapping image is formed by heat treatment after t. The configuration is such that a nonlinear element is formed in a portion.

Specifically, an insulating film of the metal oxide used for the row or column side electrode is formed at the interface between the display electrode and the electrode on the row or column side 1 using oxygen in the oxide transparent electrode used as the display electrode. It forms a nonlinear element.

[Embodiments of the invention]

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Polycrystalline 3i is deposited as row or column electrodes 2 on a glass substrate 1 to a thickness of 0.3 .mu.m by vapor phase chemical reaction (CVD) and patterned to a width of 25 .mu.m by photoetching.

Next, the electrode 'l' Q (■ndiu
m'l'in 0xide) is formed to a thickness of 0.2 μm over the entire surface by high-frequency sputtering. Then, by photo-etching, a 220 μm×200 μm rectangle is followed by a 255 m×30 Itm protrusion, and patterned so that this protrusion overlaps the previously formed row or column side electrode 2. and 30 at 400C in nitrogen.
Heat treat for minutes. Through this heat treatment, oxygen in ITOa diffuses to the polycrystalline Si side serving as the first row or column side electrode 2, and a thin 5i02 layer is formed at the interface with the polycrystalline Si, forming a nonlinear element. .

With the above steps, the nonlinear element is completed.

In order to form a liquid crystal display device, an alignment film 6 is formed and aligned over the entire surface of the substrate on the nonlinear element side. On the opposing substrate, ITO is formed as a counter electrode 4 on the entire surface of the glass substrate 5 by high frequency sputtering to a thickness of α3 μm, and then is patterned into a band shape of 210 μm in width by photoetching. An alignment film 6 is formed on this to form a counter substrate.

These two substrates are combined to form a cell and liquid crystal 7 is sealed.

゛ With the above steps, the liquid crystal display device is completed. At this time, it is necessary to change the alignment treatment method and the combination of polarizing plates according to the display mode of the liquid crystal.

[Example 2] Another example is shown in Figure 3! This will be explained with reference to Figure 4.

Polycrystalline Sil is formed on the glass substrate 8 as row or column side electrodes 9.
: Deposited to a thickness of 0.3 μm by CVD and photoetched to form a protrusion as shown in Fig. F)113. Next, as a display electrode 1O, ITO is formed to a thickness of 0.2 μm over the entire surface by high-frequency sputtering, and is formed into a rectangle of 220 μm×200 μm by photoetching, and patterned so as to overlap the projections of the row or column side electrodes 9. Thereafter, in the same manner as in Example 1, a liquid crystal display device is completed through steps such as heat treatment, formation of an alignment film 12, formation of a nine-face substrate including a face electrode 11, assembly of cells, and filling of liquid crystal.

[Example 3] Another embodiment will be explained with reference to FIGS. 5 and 6.

Polycrystalline S is formed on the glass substrate 13 as row or column side electrodes 14.
I was deposited to a thickness of 0.3 .mu.m by CVD and patterned to a width of 25 .mu.m by photoetching. Next, an insulating layer 17 is applied to the entire surface of the substrate and silicate glass (PSG) is applied by CVD.
The row or column side electrodes 14 are formed with a thickness of 0.6 μm by the D method.
Through holes of 25 .mu.m.times.13 .mu.m are formed on the top by dry etching using CFa plasma. Then, ITO is formed as a display electrode 15 by high frequency sputtering so as to be in direct contact with the row or column electrode 14 through this through hole, and then patterned into the shape shown in FIG. 5. Thereafter, as in Example 1-2, a liquid crystal display device is completed through steps such as heat treatment, formation of an alignment film 18, formation of a counter substrate with a counter electrode 16, assembly, and filling of liquid crystal.

In the above embodiments, ITO and polycrystalline S1 are used for the display electrode and the row or column side electrodes, respectively.

The combination of these materials is not limited to this, and the display electrode may include another oxide transparent electrode, and the row or column side electrode may contain an oxide layer containing oxygen in this oxide transparent electrode. Any combination of metals that can form .

〔Effect of the invention〕

According to the present invention, the number of photomasks used during the manufacturing process can be reduced to two for completing the nonlinear element and three for cutting the liquid crystal and completing the display device. The process can be greatly simplified.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a plan view of an embodiment of the present invention.
3 is a plan view of another embodiment of the present invention, and FIG. 4 is a plan view of the nonlinear element side substrate of FIG. 3.
A line sectional view, FIG. 5 is a plan view of another embodiment of the present invention, and FIG.
The figure is a cross-sectional view of the nonlinear element side substrate in Figure 5 and the line 7.
The figure is a schematic cross-sectional view of a conventional MIM element, and Figure 8 is an MIM element.
It is an example of the voltage-DC characteristic of an element. 1.5, 8, 13.22... board, 2,9.14...
- Row or column side electrodes, 3, 10.15... Display electrodes. 4.11.16... Counter electrode, 19... Lower metal layer. 20... Upper metal layer, 21... Insulating thin film.

Claims (1)

[Claims] A liquid crystal display device in which a liquid crystal is sealed between one or two substrates, an independent display electrode on at least one of the substrates, and a nonlinear element connected in series to the display electrode. In,
1. A method of manufacturing a liquid crystal display device, which comprises forming a row or column side electrode and a transparent oxide electrode as a display electrode directly overlapping each other and then heat-treating to form a nonlinear element. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the heat treatment is performed in an inert gas. 3. In claim 1 or 2, the row or column side electrodes are made of polycrystalline Si, crystallized Si, or amorphous S.
A method for manufacturing a liquid crystal display device, characterized in that i.