JPS61183620A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent the breakdown of electrically insulating thin film by releasing static electricity generated during orientation from a substrate through a ground circuit. CONSTITUTION:Plural display electrodes 2, a grounded electric conductor 9 and electric conductors 10 for connecting the electrodes 2 to the conductor 9 are simultaneously formed on a substrate 1 for liq. crystal display elements. Circuits 3 for giving electric signals by interposing the electrically insulating thin films 4 to the electrodes 2 are formed, and a thin film 8 for the orientation is formed on the whole surface of the substrate including the electrodes 2, the conductors 9, 10 and the circuits 3. The surface of the thin film 8 is oriented while the conductor 9 is grounded, and then the conductors 10 are cut off.

Description

[Detailed Description of the Invention] (a) Purpose of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a liquid crystal display element, and particularly relates to a method for manufacturing a liquid crystal display element, and particularly a structure in which an electrical signal is applied to each display electrode via an electrically insulating thin film. The present invention relates to a method of manufacturing a liquid crystal display element having the following.

[Prior art]

A nonlinear resistance element (Metal-Insulator-Metal) has a metal-insulator-metal structure on the display electrode on the substrate.
2. Description of the Related Art Liquid crystal display elements that supply electrical signals through tal elements (hereinafter abbreviated as MIM elements) have come into general use. This MIM element is formed by interposing an electrically insulating thin film in the middle of a conductor that supplies signals to display electrodes on a substrate. MIM elements have a non-linear structure in which they exhibit high resistance when the voltage of the input signal to the conductor is low, and have low resistance when the voltage of the input signal is high enough to display a liquid crystal display. It has excellent characteristics and has the effect of preventing the occurrence of so-called cross voltage, in which electrical signals leak to adjacent display electrodes when the liquid crystal is driven.

Incidentally, when manufacturing a substrate for a liquid crystal display element, an alignment film is finally formed on the substrate, and the surface of the alignment film is subjected to an alignment treatment by a rubbing method.

[Problem that the invention seeks to solve]

At this time, since the thickness of the insulating thin film forming the aforementioned MIM element is formed to be 300 to 700 thick, the static electricity generated during the above-mentioned alignment process has an extremely high probability of destroying this insulating thin film. do. This causes the MIM element to short-circuit, so when driving, the MIM element
There is a problem in that the effect of preventing the generation of crosstalk voltage by using the M element cannot be achieved. In addition, in order to remove this static electricity, a method of providing a circuit for discharging static electricity through the substrate or the rubbing material used in the above-mentioned rubbing method has been used, but this method has not been sufficiently effective.

This invention is suitable for mass production of liquid crystal display elements that prevent liquid crystal display elements having a structure in which electrical signals are applied to each display electrode through an insulating thin film from being destroyed by static electricity generated during alignment processing. A manufacturing method is provided.

(B) Structure of the Invention The method for manufacturing a liquid crystal display element according to the present invention includes a substrate for a liquid crystal display element, a plurality of display electrodes, a ground conductor, and a connection for connecting each display electrode to the ground conductor. A circuit consisting of a first conductor which is patterned simultaneously with a conductor and supplies an electric signal, and a second conductor which supplies an electric signal to each of the display electrodes from the first conductor with an electrically insulating thin film interposed therebetween. , then forming a thin film for alignment on the entire surface of the substrate, performing an alignment treatment on the thin film for alignment while the ground conductor is grounded, and then cutting the connecting conductor.
It is characterized by

Specific examples of the substrate material include borosilicate glass, ceramics, silicon wafer, and the like. At this time, sodium glass may be used, but in this case it is necessary to form an insulating film such as silicon dioxide SiO2 on the surface.

As the first conductor, tantalum Ta, chromium Cr, aluminum AN, etc. can be used. However, considering the stability of operation of the manufactured MIM type liquid crystal display element, Ta is preferable.

Further, when an anodic oxidation method is used to form the insulating thin film, the obtained insulating thin film becomes Ta205. When patterned using a photolithographic method or the like, it may be other insulating material such as aluminum oxide AA203.

In addition to Ta, nickel N t '-chromium Cr, silver Ag, copper Cu, gold Au, etc. may be used for the second conductor. Generally, Ta5Ni and Cr are often used.

The most preferable combination is to use Ta as the material for the first and second conductors and use Ta205 as the material for the insulating thin film.

In addition, it is preferable to use In2O3 for the display electrode, the ground conductor, and the connection conductor, but in addition, tin oxide 5n
02, AI, Ag, Cu, etc. may also be used.

Further, although it is preferable to use 5i02 for the alignment thin film, other insulating materials such as a polyimide film or magnesium fluoride MgF2 may be used.

〔Example〕

The present invention will be described in detail below based on embodiments shown in the drawings.

Note that this invention is not limited to this.

FIG. 1 is a sectional view showing a portion of a liquid crystal display element manufactured by the manufacturing method according to the present invention.

(1) is a substrate, (2) is a display electrode, (3) is a first conductor that supplies electrical signals, (4) is an electrically insulating thin film, (5)
is a second conductor that provides an electrical signal to the display electrode (2) via the thin film (4). An MIM element (6) is formed on the surface of the substrate (1), and an alignment thin film (8) subjected to alignment treatment is formed on the surface of the substrate (1) including the MIM element (6). . A strip electrode (2a) parallel to the plane of the paper in FIG. 1 is formed on the counter substrate (la).
) An alignment thin film (8a) that has been subjected to alignment treatment is also formed on the surface of the counter substrate (1a). A liquid crystal (7) is sealed in a space sandwiched between these alignment thin films (8) and (8a).

A liquid crystal display element having such a structure is driven by a so-called dot matrix method. This method is one of the measures to meet the demands of liquid crystal display elements as information display means, such as higher density display units and higher density display screens.

Next, an embodiment of the manufacturing process of a liquid crystal display element according to the present invention will be described using FIGS. 2 to 5.

First, in the first step, a plan view is shown in FIG.
As shown in the A-A cross-sectional view in Figure (b), a substrate (1
), a plurality of display electrodes (2) and a ground conductor (9
) and a connecting conductor α0) connecting the display electrode (2) to the ground conductor (9) are patterned using a transparent conductive film. This transparent conductive film is made of, for example, indium oxide In2O3.
Formed by etc.

Next, in the second step, as shown in FIG. 3 (a plan view is shown in al, and a cross-sectional view taken along the line B-B in FIG. 3) Form a pattern. At this time, the first conductor (3) is formed of a metal material such as tantalum Ta, and has a conductor of 2000 to 4000.
A pattern is formed in the thickness of a person so that its cross section in a direction perpendicular to its extending direction forms a substantially trapezoidal shape. For forming such patterns, a technique that combines photolithographic technique, plasma exhaust method, reactive ion etching (RIE) method, etc. is often used. In addition, the first
A thin film of tantalum pentoxide (Ta205) with a thickness of 2000 to 400 μm is formed as an insulating thin film (4) on the surface of the conductor (3).

However, in the region of the first conductor (3) where the MIM element (6) (Fig. 1) is to be formed, a photosensitive material such as a photoresist is formed in advance, and the photoresist is removed after the above treatment. Remove and apply a thickness of 300 to 7
00 to form a thin film of Ta205.

Then, as shown in FIG. 4(a) as a plan view and as shown in FIG. 4(b) as a cross-sectional view taken along the line C-C, the first conductor (3) is inserted through the insulating thin film (4). The second electrode connected to the display electrode (2)
A conductor (5) is formed. At this time, as mentioned above, the second
The conductor (5), the insulating thin film (4), and the first conductor (3) can function as an MIM element having nonlinear characteristics when driving the liquid crystal display element.

Here, nonlinear characteristics mean that when the voltage of the input signal to the first conductor is small, the resistance becomes high, and when the voltage of the input signal is high enough to display a liquid crystal display, the resistance becomes low. This is a characteristic related to the resistance value such that In other words, it is a voltage vs. current characteristic having the so-called Poole-Frankel effect, which is expressed as 1=k.V.exp (.beta./V''), where k and .beta. are constants. Note that the second conductor (5) is formed of a material such as tantalum Ta.

Next, in the third step, the substrate (1
) A thin film for alignment (8) is formed over the entire surface of the substrate. The alignment thin film (8) is made of silicon dioxide 5i02, for example.
It is formed from etc. Therefore, after the ground conductor (9) is grounded, the surface of the alignment thin film (8) is subjected to alignment treatment. As described above, the rubbing method is often used for the orientation treatment, and therefore static electricity is generated due to friction on both surfaces of the orientation thin film (8) made of an insulating material.

The generated static electricity is led to the display electrode (2) in contact with the alignment thin film (8), the ground conductor (9), the second conductor (5), and the connecting conductor αψ. It is discharged to the external ground to which the ground conductor (9) is connected via a series circuit constituted by the connecting conductor α0 and the ground conductor (9). In this way, destruction of the insulating thin film (4) in the formation region of the MIM element (6) due to static electricity, which may have an electric field of about several thousand V/cI11, is prevented.

Next, in the fourth step, the plan view is shown in FIG.
The substrate (
1) Cut the connecting conductor αΦ. This cutting can be done, for example, by yttrium aluminum garnet (YAG).
This is carried out using a YAG laser device (not shown) using a crystal (hereinafter abbreviated as YAG). Therefore, the display electrode (
2) constitutes a circuit that is connected to the first conductor (3) only via the second conductor (5) and the MIM element (6).

In this way, the MIM element (6) is prevented from being destroyed by static electricity, in other words, the first conductor (3) and the second conductor (5) are not directly electrically connected, and the pool
A liquid crystal display element including an MIM element (6) having the Frankel effect can be manufactured. At this time, the connected conductor -
Orientation thin film (8) covering the excised part when the
will also be removed, but the width of this removed portion is 1 μm ~
It has been confirmed that the thickness is about 2 μm, and that the influence on the overall alignment effect achieved by the alignment treatment is negligible.

Furthermore, the same effect can be obtained by changing the order of steps in the above-described embodiment and implementing the first step between the second and third steps described above. In this case, the first and second conductors (3
) On the surface of (5), the connecting conductor α [and the display electrode (2), etc. are formed by a transparent conductive film, and the cross section of the substrate (2) corresponding to the peak in Figure 4 is shown in Figure 6 (a). The cross section of the substrate (2) corresponding to FIG. 5(b) is as shown in FIG. 6(b).

In this way, the static electricity generated during the alignment process using the rubbing method is sufficiently discharged to the outside, and destruction of the insulating thin film (4) constituting the MIM element is reliably prevented.

Furthermore, regarding the manufacturing process, the configuration of the circuit that discharges static electricity is simple as shown in Figure 2, and the circuit is manufactured at the same time in a single process like the first process described above. is simplified and the number of man-hours is greatly reduced.

(C) Effects of the Invention According to this invention, the static electricity generated on the surface of the alignment film during the alignment process is sufficiently discharged to the outside of the substrate by the grounding circuit, thereby reliably preventing destruction of the electrically insulating thin film that occurs during the alignment process. be done. Furthermore, this grounding circuit has a simple configuration and is manufactured through a simple process. Therefore, it is possible to manufacture a liquid crystal display element compatible with a display method such as a dot matrix method with a small number of man-hours and a high yield.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a liquid crystal display element manufactured by the manufacturing method according to the present invention, and FIGS. (Figure mountain)
~Figure 5(b) is a sectional view taken along the arrows A-A, B-B, CC, and D-D of Figures 2(a) to 5(a), respectively.
The figure is a sectional view showing another manufacturing process of the present invention. (1)--One substrate (2)-Display electrode,
(3)--first conductor, (41--electrically insulating thin film, (5)-second conductor, (6)--MI
M element! 71---Liquid crystal, (8)---
Alignment film, (9L-m-ground conductor, (l[+>・
・~Connecting conductor. Figure 1 a Figure 2 Figure 3 (a) (a) (b) Figure 5 (a) Procedural correction tooth (release) June 12, 1985

Claims (1)

[Claims] 1. (a) A plurality of display electrodes, a ground conductor, and a connecting conductor connecting each display electrode to the ground conductor are simultaneously patterned on a substrate for a liquid crystal display element. (b) interposing an electrically insulating thin film on each of the display electrodes to form a circuit that provides an electrical signal; (c) then applying a method to the entire surface of the substrate including each of the electrodes, each of the conductors, and the circuit; A liquid crystal display element characterized in that: an alignment thin film is formed, an alignment treatment is performed on the alignment thin film while the ground conductor is grounded, and (d) the connecting conductor is cut. manufacturing method.