JPS6199186A - 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 industrial application) The present invention relates to a method for manufacturing a liquid crystal display device equipped with a non-linear element having a metal-oxide film-metal structure (prior art). There is a growing demand for liquid crystal display devices (LCDs) to be adapted to ancient times. In a large capacity h1 liquid crystal display device,
A multiplex drive system with matrix display has been adopted. The drawback of this method is that the display is limited to a few dozen diffraction levels, and for insects larger than that, a sufficient contrast ratio between on and off pixels cannot be obtained.

One way to overcome this shortcoming of liquid crystal display devices is to use nonlinear resistance elements (hereinafter abbreviated as MIM elements) with a total bending-oxide film-metal structure to directly connect pixels on the sides. A matrix drive system that uses switch drive is attracting attention.

An example of a conventional Mil-LCD is shown in FIG. This L C
D is manufactured as follows. On the glass substrate 1, L,
Ta1i2 is formed by a sputtering method, etc., and Ta is patterned by a photo-edge puffer method. As a result, the Ta wiring and the lower metal of the MIM element were formed. The buttered Ta pattern 2 of 111j is anodized using a citric acid aqueous solution or the like to form an oxide film 3. Further, a metal such as Cr or Ni-0r is deposited on the upper layer and patterned to form the upper metal 4. This completes the MIM device. Furthermore, after this,
A transparent i-pole 5 is formed to serve as one pixel electrode of a liquid crystal display device. After that, it is assembled using the same process as a normal LCD.

However, when considering the combination of the characteristics of the MIM element and the electrical and optical characteristics of the liquid crystal, it is found that the area ratio between the pixel electrode and the M element must be in the order of several thousand to ten thousand. I've come to understand. Therefore, the dimension of the MIM element for a pixel of, for example, 300 .mu.-angle is about 3 .mu.-angle, and the precision of the graphography technique used in conventional LCD manufacturing is insufficient. Therefore, a method was devised to form an MIM element using the side surface 2a of the lower wiring metal 2, as shown in FIG.
(See Publication No. 178320).

(Problems to be Solved by the Invention) In the MIM element, in addition to taking into account the voltage applied to the liquid crystal during AC drive, it is necessary that the two metals used to form the MIM element are the same. desirable. As clearly shown in the graph of FIG. ) varies greatly depending on which side of the positive side is used for driving. This difference in characteristics depending on the bias direction causes deterioration of the liquid crystal material because a DC component remains during AC driving.

In conventional manufacturing methods, selective patterning is not possible when using the same metal, so a different material must be used for the second metal of the MIM element.

An object of the present invention is to provide a manufacturing method that enables the use of the same material for the two metals forming the M, IMi/: child, and that enables the production of M I M -L CDs with stable characteristics and fine patterns. It is to propose (to do).

(Steps for Solving Problems) In the method of manufacturing a liquid crystal display device including a non-linear element formed by sequentially laminating a first gold PA layer, an insulator layer and a second metal layer according to the present invention, A positive resist is applied to the front side of the substrate on which one metal layer and an insulator layer are formed on the surface, and then mask exposure is performed from the back side of the substrate to form a second metal layer around the first metal layer. after removing the resist in the predetermined areas to be deposited, depositing on the substrate surface the same material that formed the first metal layer;
Next, the resist is removed and a second metal layer is formed in the above-mentioned predetermined region.

(Function) In the manufacturing method according to the present invention, alignment of the fourth metal layer and the second metal layer can be performed accurately or by mask exposure from the back side of the substrate. A transverse MIM element (FIG. 4) can be easily produced. Also, since the second metal layer is patterned or lifted off, the first metal layer and the second metal layer can be formed of the same material.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1(a) to 1(g) are drawings sequentially showing schematically steps of an embodiment of the present invention. (a) First, a thin Ta pattern of 3000 to 5
The lower gold fi 12 is formed by sputtering to a thickness of 100 mm, and the lower gold fi 12 is formed by buttering. This lower metal 12
becomes a leet electrode at the same time. Next, this Ta thin film 12
The surface of the P7. Shape the Ta oxide film 13
+12. The steps up to this point are the same as the conventional manufacturing method. (!l) Next, mold it into a shape and apply Nostoto 1 (Nbrey Co., Ltd., A7M3000-: (1st grade)) to a thickness of about 2 μm.
After J4iL and pre-beta, exposure is performed from the back side using a mask 15 (the light shielding portion is indicated by 15'). (C) When this substrate is developed, the resist I4 will leave the mask pattern and the Ta electrode portion 16.6(d) Next,
A 1゛λ thin film I7 is formed on the surface by sputtering in a 1゛l layer weighing 11 g. After that, when the resist is stripped off, the Ta of the resist 13E is removed in the same way as the resist stripping. (lifted off), the shape of the Ta 18 remaining on the top becomes as shown in FIG. 1(e). In this way, an M element using the same side structure as the conventional example shown in FIG. 4 was realized. (') Furthermore, ETOM is deposited on the surface using a transparent conductive film to a thickness of approximately +00 mm, and the pixel electrode I9 is formed by patterning.
g) is a partial plan view of the LCD thus formed.

Figure 2 shows the thus formed Ta -Taxes -
2 is a graph of V-1 characteristics of MIM elements with different Ta configurations. As is clear from the comparison with the V-1 characteristic of the MIM element having the Ta/TatOs-AL configuration shown in Fig. 4,
In the MIM element according to this embodiment, the difference in characteristics depending on the bias direction is small. That is, there is almost no remaining DC component during AC driving, and deterioration of the liquid crystal can be prevented.

(Effects of the Invention) According to the present invention, it is possible to easily realize an MIM element having a side structure in which the upper and lower sides are made of the same metal.

Furthermore, the present invention provides a high-density and highly reliable MIM
-LCI) is a very effective method for manufacturing.

[Brief explanation of drawings]

FIGS. 1(a) to 1(g) are process explanatory diagrams sequentially showing schematically the steps of an embodiment of the present invention. FIG. 2 is a graph of V (voltage) (current) characteristics of the MiM element according to the present invention. FIG. 3 is a perspective view of an example of a conventional MIM element. FIG. 4 is a sectional view of another example of a conventional MIM element. FIG. 5 is a graph of the V- characteristic of the conventional MIM element shown in FIG. ! ...Substrate, 2...Lower metal, 3...
Oxide film, 4... Upper metal, 5... Transparent electrode (
pixels). Patent Applicant Sharp Co., Ltd. Agent Patent Attorney Blue and White Blue and White 1i to Two Idiots! (O) (・) (b) (f) Figure 3

Claims (1)

[Claims] (1) In a method for manufacturing a liquid crystal display device including a non-linear element formed by sequentially laminating a first metal layer, an insulator layer, and a second metal layer, an insulator layer is formed on the first metal layer and the surface thereof. A positive resist is applied to the front side of the substrate, and then mask exposure is performed from the back side of the substrate to remove the resist in predetermined areas where the second metal layer is to be deposited around the first metal layer. , depositing the same material on the substrate surface as the material that formed the first metal layer;
A method for manufacturing a liquid crystal display device, comprising: then removing the resist to form a second metal layer in the predetermined region.