JPH0367246B2 - - Google Patents

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 to a method for producing a liquid crystal display element, and particularly relates to a method of manufacturing a liquid crystal display element, and particularly to a method for producing a liquid crystal display element, and particularly relates to a method of manufacturing a liquid crystal display element, and particularly to a method for producing a liquid crystal display element. 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-) having a metal-insulating film-metal structure on the display electrode on the substrate
Liquid crystal display elements that supply electrical signals via metal elements (hereinafter abbreviated as MIM elements) are becoming commonly used. 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. And the MIM element is
It has non-linear characteristics such that it has high resistance when the voltage of the input signal to the conductor is small, and low resistance when the voltage of the input signal is high enough to produce a liquid crystal display. , has the effect of preventing the generation of so-called crosstalk 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 above-mentioned MIM element is formed to be 300 Å to 700 Å, the static electricity generated in the above-mentioned alignment process has an extremely high probability of destroying this insulating thin film. As a result, the MIM element is short-circuited, so there is a problem that the effect of preventing the generation of crosstalk voltage by using the MIM element during driving cannot be realized. 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 aimed at 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. This provides a suitable manufacturing method.

(B) Structure of the Invention The method for manufacturing a liquid crystal display element according to the present invention includes a method for manufacturing a liquid crystal display element, which includes a plurality of display electrodes, a ground conductor, and a connecting conductor that connects each display electrode to the ground conductor on a substrate of the liquid crystal display element. Forming a pattern with the body at the same time,
A circuit consisting of a first conductor for supplying an electric signal and a second conductor for supplying an electric signal to each of the display electrodes from the first conductor with an electrically insulating thin film interposed therebetween is formed, and then a circuit is formed over the entire surface of the substrate. The present invention is characterized in that a thin film for alignment is formed, an alignment treatment is performed on the thin film for alignment while the ground conductor is grounded, and then the connecting conductor is cut.

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, silicon dioxide on the surface
A process to form an insulating film such as SiO ₂ is required.

The first conductor is tantalum Ta or chromium.
Cr, aluminum Al, 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 Ta ₂ O ₅ . When forming patterns using photolithographic methods, the pattern is formed using aluminum oxide.
It may also be other insulating materials such _{as Al2O3} .

For the second conductor, other than Ta, nickel (Ni), chromium (Cr), silver (Ag), copper (Cu), gold (Au), etc. may be used. Generally, Ta, Ni, and Cr are often used.

Also, as a material for the first and second conductors,
Ta is used, and Ta ₂ O ₅ is used as the material of the insulating thin film.
Most preferred is a combination using

Further, it is preferable to use In ₂ O ₃ for the display electrode, the ground conductor, and the connecting conductor, but other materials such as tin oxide SnO ₂ , Al, Ag, and Cu may also be used.

Although it is preferable to use SiO ₂ for the alignment thin film, polyimide film or magnesium fluoride film may also be used.
Other insulating materials such as MgF ₂ may also 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 for supplying an electric signal, 4 is an electrically insulating thin film, and 5 is a second conductor for supplying an electric signal to the display electrode 2 via the thin film 4.
It is a conductor. A MIM element 6 is formed on the surface of the substrate 1, and an alignment thin film 8 subjected to an alignment treatment is formed on the surface of the substrate 1 including the MIM element 6. A strip-shaped electrode 2a parallel to the paper plane of FIG. 1 is formed on the counter substrate 1a, and an alignment thin film 8a that has been subjected to an alignment treatment is also formed on the surface of the counter substrate 1a including the strip-shaped electrode 2a. 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 configuration 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, the plan view is shown in Figure 2a,
As shown in FIG. 2b, a cross-sectional view taken along the line A-A,
For example, on the surface of a substrate 1 made of a material such as borosilicate glass, a plurality of display electrodes 2, a ground conductor 9, and a connection conductor 10 connecting the display electrodes 2 to the ground conductor 9 are formed using a transparent conductive film. Twist to form a pattern. This transparent conductive film is formed of, for example, indium oxide In ₂ O ₃ or the like.

Next, in the second step, as shown in a plan view in FIG. 3a and a sectional view taken along the line B-B in FIG.
form a pattern. At this time, the first conductor 3 is
For example, it is formed from a metal material such as tantalum Ta,
A pattern is formed to a thickness of 2000 Å to 4000 Å so that the cross section in the direction perpendicular to the extending direction forms a substantially trapezoidal shape. For forming such patterns, techniques that combine photolithography, plasma evacuation, reactive ion etching (RIE), and the like are often used. Furthermore, tantalum pentoxide with a thickness of 2000 Å to 4000 Å is applied to the surface of the first conductor 3 using an anodizing method.
A thin film of Ta ₂ O ₅ is formed as the insulating thin film 4 . However, the MIM element 6 (Fig. 1) of the first conductor 3
A photosensitive material such as a photoresist is previously formed in the area where the area is to be formed, and after the above treatment, the photoresist is removed and a thickness is applied to the area.
A thin film of 300 Å to 700 Å Ta ₂ O ₅ is formed. and,
As shown in FIG. 4a in a plan view and in FIG. form 5. At this time, as mentioned above, the second conductor 5
, the insulating thin film 4 and the first conductor 3 are MIMs that have non-linear characteristics when driving the liquid crystal display element.
It can have a function as an 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 V-current I characteristic having the so-called Poole-Frankel effect, which is expressed as I=k·V·exp(β√), where k and β are constants. Note that the second conductor 5 is made of a material such as tantalum Ta.

Next, in a third step, an alignment thin film 8 is formed over the entire surface of the substrate 1 that has undergone the above-described steps. The alignment thin film 8 is made of silicon dioxide, for example.
Formed from SiO ₂ etc. Therefore, after grounding the ground conductor 9, 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, the ground conductor 9, the second conductor 5, and the connection conductor 10 that are in contact with the alignment thin film 8;
is discharged to the external ground to which the ground conductor 9 is connected via a series circuit constituted by. Thus the divisor
This prevents destruction of the insulating thin film 4 in the region where the MIM element 6 is formed due to static electricity, which may have an electric field of 1000 V/cm.

Next, in the fourth step, a plan view is shown in FIG.
As shown in FIG. 5b, a sectional view taken along line D-D,
The connecting conductor 10 of the substrate 1 is cut. This cutting is performed by a YAG laser device (not shown) using, for example, yttrium aluminum garnet (YAG, hereinafter abbreviated as YAG) crystal. Therefore, the display electrode 2 and the second conductor 5
A circuit connected to the first conductor 3 only via the MIM element 6 is configured. In this way, the MIM element 6 is prevented from being destroyed by static electricity,
In other words, a liquid crystal display element including an MIM element 6 having the Poole-Frankel effect can be manufactured without direct electrical conduction between the first conductor 3 and the second conductor 5. At this time, as the connecting conductor 10 is removed, the alignment thin film 8 covering the removed portion is also removed, and the width of this removed portion is 1 μm to 1 μm.
The thickness is approximately 2 μm, and it has been confirmed 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 a connecting conductor 10 on the surface of the second conductors 3 and 5.
The display electrodes 2 and the like are formed of transparent conductive films, and the cross section of the substrate 2 corresponding to FIG. 4b is shown in FIG. 6a.
The cross section of the substrate 2 corresponding to FIG. 5b is shown in FIG. 6b.
It becomes as shown in .

In this way, the static electricity generated during the alignment process using the rubbing method is sufficiently discharged to the outside, and the MIM
Destruction of the insulating thin film 4 constituting the 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 the present 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, so that the breakdown of the electrically insulating thin film that occurs during the alignment process is ensured. is prevented. Furthermore, this grounding circuit has a simple configuration and is manufactured through a simple process. Therefore, with less man-hours and high yield,
It becomes possible to manufacture a liquid crystal display element that is compatible with a display method such as a dot matrix method.

[Brief explanation of drawings]

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. 2 to 5 are views showing the manufacturing process of an embodiment of the present invention, in which a is a plan view; b is A-A, B-B, C- of a, respectively
C, DD arrow sectional views, and FIG. 6 are sectional views showing other manufacturing steps of the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Display electrode, 3... First conductor, 4... Electrically insulating thin film, 5... Second conductor,
6...MIM element, 7...Liquid crystal, 8...Alignment film,
9...Grounding conductor, 10...Connecting conductor.

Claims (1)

[Claims] 1 (a) Simultaneously pattern forming a plurality of display electrodes, a ground conductor, and a connecting conductor that connects each display electrode to the ground conductor 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 oriented the entire surface of the substrate including each of the electrodes, each of the conductors, and the circuit; forming a thin film for
A method for manufacturing a liquid crystal display element, comprising: performing an alignment treatment on the alignment thin film while the ground conductor is grounded; (d) then cutting the connecting conductor.