JPH03125123A - Active matrix display device and its manufacture - Google Patents

Abstract

PURPOSE:To preclude an electric leak between a light shielding layer and an active element and between a scanning line and a signal line by forming an insulating film on the light shielding layer formed below the active element and scanning line and signal line. CONSTITUTION:The display device is equipped with the light shielding layer 2 formed below the active element 19 and scanning line 23 and signal line 22 in an area other than an area wherein a picture element electrode 9 is formed and the insulating film 4 formed on the light shield layer 2. In this case, the light shielding layer 2 is provided on the side 20 of a active matrix substrate 20, so the width of the light shielding layer need not be set in consideration of an error of the superposition of the active matrix substrate 20 and a counter substrate 21. Therefore, the area of picture elements on a display screen does not decrease. The insulating film 4 is provided on the light shielding layer 2, so no electric leak is caused between the light shielding layer 2, and active element 19 and conductors 22 and 23. Thus, the display device where the electric leak is surely precluded between the light shielding layer 2 and active element 19, and between scanning line 23 and signal line 22 is obtained at high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an active matrix display device having black stripes functioning as a light-shielding layer, and a method for manufacturing the same.

(Prior Art) Active matrix display devices using display media such as liquid crystals are attracting attention as display devices that can replace CRTs.

FIG. 3 shows a schematic cross-sectional view of an example of a conventional active matrix display device using liquid crystal. In the active matrix substrate 30 constituting this display device, a glass substrate 32
Picture element electrodes 36 are arranged in a matrix above, and a thin film transistor (hereinafter referred to as [T F TJ) 35 is connected to each picture element electrode 36 as an active element.

A drain electrode (not shown) of a TFT 35 is connected to the picture element electrode 36. TFT35 has a gate bus that functions as a scanning line! I (not shown) is connected to a source bus wiring (not shown) that functions as a signal line. The gate path wiring and the source bus wiring are provided parallel to each other in directions orthogonal to each other between a large number of picture element electrodes 36 arranged in a matrix. Picture element electrode 3
6 and the TFT 35, an alignment film 37 is formed over the entire surface.

A counter substrate 3 facing the active matrix substrate 30
1, a color filter 40 is provided on a glass substrate 33. The color filter 40 is arranged so as to overlap each picture element electrode 36 on the active matrix substrate 30. A counter electrode 39 and an alignment film 38 are formed on the entire surface of the color filter 40 .

A liquid crystal 41 is sealed between the active matrix substrate 30 and the counter substrate 31. Glass substrates 32 and 3
Polarizing plates 42 and 42 are arranged on the outer surface of 3. A backlight source 34 is provided outside the polarizing plate 42 on the active matrix substrate 30 side. In this display device, the light from the backlight source 34 that has passed through the liquid crystal 41 is viewed through red, green, and blue color filters 40.

In such a display device, red, green, and blue color filters 4 are used.
Part of the light that hits the area other than the 0 area, that is, the area between the color filters 40, is transmitted, reducing the contrast of the display screen. In order to prevent such a decrease in contrast, as shown in FIG. 4, black stripes 44 are provided between the color filters on the counter substrate 31 to function as a light shielding layer. The black stripe 44 is made of a metal film such as Cr.

(Problems to be Solved by the Invention) In the above-described active matrix display device, the pixel electrodes 36 on the active matrix substrate 30 and the counter substrate 31
It is necessary that the upper color filter be superimposed with high positional accuracy. However, the two substrates 30 and 3
Since the alignment error of No. 1 is about 10 μm, it is necessary to increase the width of the black stripe 44 by an amount corresponding to the error, that is, to make the color filter 40 smaller. Therefore, the area of the picture element decreases, and the transmittance of the display screen decreases.
That is, the brightness will decrease.

In order to avoid such a reduction in brightness, it is being considered to provide a black stripe on the active matrix substrate 30 side. When a black stripe is provided on the active matrix substrate 30, there are two types of configurations in which the black stripe is provided above the active element and the scanning line and signal line (hereinafter simply referred to as "wiring"), and a structure in which the black stripe is provided below the active element and the wiring. is possible. However, when the black stripe is provided above the active elements and wiring, the pixel electrode 9 on the active matrix substrate 30 and the counter substrate 31
A problem arises in that voltage is not effectively applied to the liquid crystal layer 41 between the upper counter electrode 39 and the liquid crystal layer 41 . Further, if the black stripe is provided below the active element and the wiring, there is a problem that electrical leakage is likely to occur between the active element and the wiring and the black stripe.

The present invention solves the above-mentioned problems, and an object of the present invention is to have a light-shielding layer formed below an active element and wiring, and to provide electrical connection between the light-shielding layer and the active element and wiring. An object of the present invention is to provide an active matrix display device that does not cause target leakage.

Another object of the present invention is to provide a method for manufacturing the above active matrix display device.

(Means for Solving the Problems) An active matrix display device of the present invention includes a pair of insulating substrates, a large number of picture element electrodes arranged in a matrix on the inner surface of one of the pair of substrates, An active matrix display device comprising an active element connected to each of the picture element electrodes, and a scanning line and a signal line formed between the picture element electrodes and selectively driving the active element. A light-shielding layer formed below the active element, the scanning line, and the signal line in a region other than the region where the elementary electrode is formed, and an insulating film formed on the light-shielding layer. , thereby achieving the above objective.

Further, in the method for manufacturing an active matrix display device of the present invention, the upper surface of the light shielding layer is oxidized by at least one of anodic oxidation, plasma oxidation, and thermal oxidation to form the insulating film. It has a process of
The above objective is thereby achieved.

(Function) In the active matrix display device of the present invention, since the light shielding layer is provided on the active matrix substrate side, it is necessary to set the width of the light shielding layer in consideration of the error in overlaying the active matrix substrate and the counter substrate. There is no. Therefore, the area of picture elements on the display screen does not decrease. Furthermore, since the insulating film is provided on the light shielding layer, electrical leakage does not occur between the light shielding layer and the active elements and wiring.

In the method for manufacturing an active matrix display device of the present invention, the insulating film formed on the light-shielding layer is formed on the top surface of the light-shielding layer by at least one of anodic oxidation, plasma oxidation, and thermal oxidation. Formed by oxidation. Therefore, the insulating film is formed to reliably cover the light shielding layer, and electrical leakage between the light shielding layer and the active elements and wiring is reliably prevented.

(Example) The invention will now be described with reference to examples.

FIG. 1 shows a sectional view of one embodiment of an active matrix display device of the present invention. FIG. 2 shows a plan view of the active matrix substrate 20 of FIG. 1.

This example will be described below according to the manufacturing process. First, a metal layer was deposited on a glass substrate 1. This metal layer will later become a black stripe 2 functioning as a light shielding layer and an anodic oxide film 3. This metal layer includes, for example, Ta,
VSNb, Zr, AI, Mg, Zn, Cd5
A metal that can be anodized, such as N1% Cos Fe, is used. The thickness of this metal layer, which becomes the black stripe 2 and the anodic oxide film 3, is equal to the thickness of the black stripe 2 plus the layer thickness necessary to form the anodic oxide film 3. 99% of light from backlight source
In order to block the above, the layer thickness of the black stripe 2 needs to be 100 to 10,000 Å or more. In this example, Ta metal was used for this metal layer, and was deposited to a thickness of 3000 nm using a sputtering method.

Next, this metal layer was patterned into a lattice shape shown by diagonal lines in FIG. 2 by photolithography and etching. Next, the upper surface of this metal layer was anodized to form an anodic oxide film 3. The anodic oxide film 3 is formed by T
FT19, gate lot wiring 23 and source bus wiring 22
It functions as an insulating film to prevent electrical contact between the black stripe 2 and the black stripe 2. The lower part of this metal layer where the anodic oxide film 3 is not formed becomes the black stripe 2. The anodic oxide film 3 is formed by applying a chemical formation voltage of 160 V in a 3% ammonium borate aqueous solution. The thickness of the anodic oxide film 3 can be controlled by managing the time during which anodic oxidation is performed. In this embodiment, the thickness of the anodic oxide film 3 is approximately 2000 mm.

A base insulating film 4 made of S I Nx was deposited over the entire surface of the anodic oxide film 3 . A gate bus wiring 23 made of Ta metal was formed on the base insulating film 4. Gate lotus wiring 2
3 is superimposed above the grid-like black stripe 2,
As shown in FIG. 2, they are provided in parallel in one direction. A part of the gate bus wiring 23 functions as the gate electrode 5. SiN is applied to the entire surface covering the gate bus wiring 23.
A gate insulating film 6 made of x was deposited. Next, on the upper surface of the gate insulating film 6, a non-doped amorphous silicon (hereinafter referred to as RA-3i (i)) layer, which will later become the semiconductor layer 7, and a 5INX layer, which will later become the insulating layer 11, are successively deposited. I let it happen. The above 5INX layer is patterned into a predetermined shape, and only the upper part of the gate electrode 5 is left, and the insulating layer 1 is
1 was formed.

A layer of amorphous silicon doped with P (phosphorus) (hereinafter referred to as ra-3l (n'') J), which will later become the contact layer 8, was deposited over the entire surface of the insulating layer 11 by plasma CVD.Next, , this a-31(n”)
The semiconductor layer 7 and the contact layer 8 were formed by patterning the a-st layer and the above-mentioned a-st (B layer) into a predetermined shape. Provided for ohmic contact.At this point, the contact layer 8 is connected on the insulating layer 11.

A Ti metal layer was deposited on the entire surface of this substrate by sputtering, and this Ti metal layer was patterned by etching to form a source electrode 10t) and a drain electrode 10a. At this time, the contact layer 8 on the insulating layer 1'1 was also etched away at the same time, dividing it into a portion below the source electrode 10b and a portion below the drain electrode 10a.

The TFT 19 was formed as described above.

The source bus wiring 22 is formed simultaneously with the source electrode 10b and the drain electrode 10a. As shown in FIG. 2, the source bus wiring 22 is orthogonal to the gate path wiring 23 and intersects with the gate bus wiring 23 with the gate insulating film 6 interposed therebetween.

Next, an ITO film was deposited on the entire surface by sputtering. This ITO film was patterned into a predetermined shape to form a picture element electrode 9. Considering errors in mask alignment during pattern formation of the picture element electrode 9, the picture element electrode 9 was formed so that the end of the picture element electrode 9 and the end of the black stripe 2 overlapped by 1 to 2 μm. A protective insulating film 12 made of 5iN8 was deposited on the entire surface of the picture element electrode 9, and an alignment film 13 was further formed. The active matrix substrate 20 is manufactured as described above.

Counter substrate 21 facing active matrix substrate 20
In this case, a color filter 16 is formed on a glass substrate 15, and a counter electrode 17 made of ITO and an alignment film 18 are further formed on the entire surface of the color filter 16. No black stripes are formed on the counter substrate 21. Liquid crystal 14 is sealed between the thus formed counter substrate 21 and the above-mentioned active matrix substrate 20, thereby producing an active matrix display device.

In this embodiment, the black stripe 2 is formed not on the counter substrate 21 but on the active matrix substrate 20. Black stripe 2 to active matrix substrate 2
By providing it on the 0 side, the active matrix substrate 2
There is no need to set the width of the black stripe 2 in consideration of the error in overlaying the black stripe 2 and the counter substrate 21. Therefore,
There is no need to reduce the area of picture elements, and no reduction in brightness of the display screen occurs.

Further, in this embodiment, the black stripe 2 is the TFT1
9. Since it is formed below the gate bus line 23 and source bus line 22, it does not affect the voltage to be applied to the liquid crystal 14 between the picture element electrode 9 and the counter electrode 17. Furthermore, in this embodiment, since the anodic oxide film 3 is formed on the black stripe 2, electrical leakage between the black stripe 2, the TFT 19, the gate pass wiring 23, and the source bus wiring 22 is prevented.

In the method for manufacturing an active matrix display device of this embodiment, the upper surface of the black stripe 2 is anodized to form an anodic oxide film 3 that functions as an insulating film. Therefore, according to the manufacturing method of the present invention, electrical leakage between the black stripe 2, the TFT 19, the Kate Hass wiring 23, and the source bus wiring 22 is reliably prevented.

(Effects of the Invention) In the active matrix display device of the present invention, since the insulating film is formed on the light shielding layer formed below the active elements and the scanning lines and the signal lines, the light shielding layer, the active elements and the scanning lines Electrical leakage between the signal line and the signal line is prevented. Therefore, according to the present invention, a display device with high brightness can be obtained with a high yield. In the method for manufacturing an active matrix display device of the present invention, the insulating film is formed by oxidizing the upper surface of the light shielding layer using at least one of anodization, plasma oxidation, and thermal oxidation. Therefore, according to the manufacturing method of the present invention, electrical leakage between the light shielding layer, the active elements, and the scanning lines and signal lines can be reliably prevented, and the display device can be obtained with a high yield.

Figure 1 is a cross-sectional view of one embodiment of the active matrix display device of the present invention, Figure 2 is a plan view of an active matrix substrate constituting the display device of Figure 1, and Figure 3 is a conventional one. A schematic cross-sectional view of an active matrix display device, FIG.
FIG. 3 is a plan view of a counter substrate of the display device shown in the figure.

DESCRIPTION OF SYMBOLS 1, 15...Glass substrate, 2...Black stripe, 3...Anodized film, 4...Base insulating film, 5...
... Gate electrode, 6... Gate insulating film, 7... Semiconductor layer, 8... Contact layer, 9... Picture element electrode, 10
a... Source electrode, 10b... Drain electrode, 11
...Insulating layer, 12...Protective insulating film, 13.18...
・Alignment film, 14...Liquid crystal, 16...Color filter, 17...Couple electrode, 19...TPT, 20...
Active matrix substrate, 21... Counter substrate, 22
... Source bus wiring, 23... Gate bus wiring.

that's all

Claims (1)

[Claims] 1. A pair of insulating substrates, a large number of picture element electrodes arranged in a matrix on the inner surface of one of the pair of substrates, and a plurality of picture element electrodes connected to each of the picture element electrodes. An active matrix display device comprising an active element, and a scanning line and a signal line formed between the picture element electrodes and selectively driving the active element, wherein a light-shielding layer formed below the active element, the scanning line, and the signal line in the region; and an insulating film formed on the light-shielding layer;
Active matrix display device with 2. A step of forming the insulating film by oxidizing the upper surface of the light shielding layer by at least one of anodic oxidation, plasma oxidation, and thermal oxidation.
A method for manufacturing an active matrix display device according to .