JPS58130561A - Active matrix substrate - Google Patents

Abstract

PURPOSE:To obtain the substrate which can keep a charge of one digit or more, by using a transparent substrate for the substrate when the active matrix substrate for driving a liquid crystal display body is formed, coating most part of the surface by the laminated film of an SiO2 film and a conductive transparent film, and providing an element comprising polycrystal Si on the other part. CONSTITUTION:On the transparent substrate 401 made of quartz glass and the like, the SiO2 film 402 and an ITO film 403 which is the conductive transparent film are laminated and formed. A specified pattern is formed by photoetching. Then the entire surface is coated by an SiO2 film 404. Then an island shaped polycrystal film 405 is formed on the part of the film 404 where the films 403 and 402 are not present. Then heat treatment is performed, and only the exposed part is transformed into an SiO2 film 406, which is to become a gate oxide film. A polycrystal Si film 407, which is to become a mask, is provided on the film 406. Impurity introduced regions 408 and 409 are formed in the island shaped polycrystal Si film 405 by ion implantation and the like. Thereafter, an SiO2 interlayer insulating film 410 is deposited on the entire surface, an opening 411 is provided, and Al wiring metals 412 are attached to the regions 408 and 409, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an active matrix substrate for driving a liquid crystal display formed of thin film elements.

Recently, the development of active materials for driving liquid crystal displays for the purpose of displaying images is being carried out in various places.
In particular, a method in which a thin film transistor (hereinafter abbreviated as IFT) is formed on a transparent base tube (such as quartz glass) and used as a switching transistor is attracting attention. The basic structural unit corresponding to one pixel is shown in Figure 1. In the figure, 101° and 1011 are
Confucian wiring (gate wiring) 1-1102 Uj column Y Y-confucian wiring (data line) is shown. Also, 103 is the switching TFT in the 1st row and j column, and 104 is built in the Akuko Eve matrix substrate. A charge holding capacitor is shown, and 105 is a capacitor equivalent to a liquid crystal display.
It was manufactured by the process shown in (e), and the final structure was as shown in v1(e).

First, a rio film 202'l is deposited on a transparent silicone (silica glass, etc.) 2o1 by an OVD method, a polycrystalline silicon film is further formed by an avD method, and patterned by photoetching to form an island 203f of polycrystalline silicon. Forming (Second Process + (a)) Oxidize the surface of the polycrystalline silicon to form gate oxide Ia204 [7, Further, the second polycrystalline silicon:
+y$205 is formed by cvD wave (Figure 2 (b))
@1 After patterning the second polycrystalline silicon film by photoetching, impurity doping is performed by ion implantation or thermal diffusion. ◎ 205 and 206 portions are doped with impurities.
After depositing B i Os, etc.) 207 by the C'VD method, a contact hole 20B is formed by photoetching.Furthermore, the wiring metal layer 209 (aluminum thickness) is released by sputtering or vapor deposition, and patterning is performed by photoetching. C Figure 2 (d)) A conductive transparent film (prepared with TO film), which is a liquid crystal drive electrode film, is formed and patterned by photoetching. With the above steps, the attaipomat I+Task base is completed. ( Figure 2 (a)) IIIE
In Figure 2 (), a switching pipe (105 in Figure 1) is formed at the 211 part, and a charge holding capacitor (104 in Figure 1) is formed at the 2120 part.・The charge retention capacitor formed in the conventional structure as described above is similar to the IEI! (1st &+ 1o 1゜10
1') and the data line (Fig. 1, 102) and to ensure voltage resistance, an interlayer insulation film C is provided (Fig. 2, 20).
The film thickness of 7) must be as thick as about 1 μm.Furthermore, in order to make the liquid crystal display a transmissive type, the area occupied by the polycrystalline silicon (C2K1205) through which light passes is as small as possible.・Therefore, the capacitor area becomes smaller. ・For the above reasons, it is not possible to increase the capacitance value beyond a certain level. ・C-Pixel 2
In the case of 5000μ snow 1, the maximum α2PF is present) The lower limit of the static sum of the off-current of the TE and the 1-current of the liquid crystal obtained by a relatively simple and inexpensive process is 100P~50
Considering that the current value is 0Pm, in order to obtain a picture image display with sufficient display performance, the capacitance value of the charge holding capacitor C (Fig. 1, 104) should be approximately 10 times the current value. In this case, it is necessary to set it to about 2FF).IvI from iE eliminates this drawback [,
With this in mind, we proposed a structure for an active matrix base for liquid crystal displays that satisfies the above requirements and achieves good display performance by devising the manufacturing process of 77 devices and thin film capacitors. It's about doing.

The basic structural unit corresponding to one pixel in the pixel display in the actual example of the present invention is shown in Fig. 5F as in Conventional-1. The drawing numbers in this figure are 101 to 105 and 3 in Fig. 1. 501~ in the diagram
505 corresponds to this.

No.! STI? ! The present embodiment shown in is realized by the manufacturing process shown below.

In the manufacturing process shown in Fig. 4 (supply ~ (f)), pipes,
81 by OVD method on 401 Toru 88 base (Gyokuhaku Glass Cape)
402% of the ITO film is deposited, and then an ITO film 40s is formed by sputtering and patterned by photoetching. Next, an insulating film 404 (Bias type) is deposited using the OVD method (FIG. 4(a)). Next, a polycrystalline silicon film 404 is formed using the 0VT method, and patterned by photoetching. Forming the island of Conn 405・C Figure 4(b)
) The external view from above of the same cross-sectional view is patterned as shown in Figure 5. 501 in the same figure is the transparent base tube. 503
505 indicates an island of polycrystalline silicon. The gate oxide film 406 is made by oxidizing the surface of the polycrystalline silicon, which is made up of a part that becomes one electrode for a capacitor and a part that connects these parts to each other. Then, a second polycrystalline silicon film is formed on the cape using the 4071 OVD method. (Figure 4 (C))
After the second multi-crystalline silicon film 11 is patterned by photo-etching, impurities are doped by ion implantation or thermal diffusion.

408 and 4090 portions are doped with impurities.C Figure 4(d)) Next, interlayer insulation 13 (810a group) 4 is applied to the entire surface.
After depositing by 10IOVI) method, photoetch to form a contact hole 411.Furthermore, wiring metal 412C aluminum, etc.) fffff by sputtering or vapor deposition.
Then, patterning is performed by photoetching. C Fig. 4(e)) Furthermore, a second ITO film 413 which is a liquid crystal #electrodynamic
is engraved with sputtering etc. and patterned with Photoera+. ・Active matrices with a shoken structure are produced using PL soil. ・(4th evening (?)) Thin film in Figure 4 The capacitor is made of the first formed τ0 film (4
0S 1 and 1E2Kff formation LIITOII (41S)
As shown in FIG. 5, the first ITO film formed between
Connect one or more points of the MIF to the ground level of the data line signal.Compared to the conventional charge retention capacitor, which has 4 connections between the gate # line, the interlayer LP film, and the liquid crystal drive electrode. The actual implementation! By applying this, the area ratio is 20 times 1! Because it is vertical, it is possible to fabricate a charge retention capacitor with a capacity of 1%, which is 20 times larger than conventional ones. Despite the increase in wind speed in the production and photo processes, the cost increase will be limited to about 15 to 20 million yen.

As stated above (according to the present invention, only a small amount of work is required)
However, by using the obtained attentive matrices Wt, it is possible to obtain attenuated matrices with superior retention properties of - orders of magnitude or more with only an increase in I and cost. - A high-performance, low-cost liquid crystal display can be made without adding complicated and cost-increasing processes to reduce the current and increase the ON/OF Irf rPfl.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the basic unit constituting a liquid crystal display using active matrix II#.・Figure S is a diagram to explain the basic unit that constitutes a liquid crystal display using the attenuating matrix according to the present invention. ・(!L) to ( in Figure 4) 6 is a translation for explaining the at-tape matrix board manufacturing process according to the present invention. Figure 5 is a diagram outside the pattern in the process of Figure 4 (b). Applicant Co., Ltd. Jiku Seikosha Figure 3 14-

Claims (1)

[Claims] A source, a drain, and a channel are formed on the first polycrystalline silicon layer, an arsenic acid film is formed on the first polycrystalline silicon layer, and a second polycrystalline silicon layer is formed on the silica layer. In the structure of an attenuating matrix II substrate consisting of a thin film transistor formed using a layer as a gate, the first polycrystalline silicon
A first electrode made of a conductive transparent film and an insulating film are formed using the first layer as a formation needle, and the second polycrystalline silicon layer is formed with an interlayer I? ! Ill? a second electrode consisting of a conductive transparent film formed with a contact hole and coupled to the drain electrode of the first polycrystalline 21197 layer; 1. An active metal 11x base plate, characterized in that the first electrode, the insulating film, the interlayer P film, and the second electrode form a power holding capacitor.