JP2000206562A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of an optical leakage current and to perform an image display of high contrast and quality by forming a thin film transistor on an insulative transparent substrate and providing a reflection preventive film between a metallic wiring layer and an inter-layer insulation layer. SOLUTION: A thin film silicon layer 10 is formed on the inter-layer insulation layer 9 formed on a first insulative transparent substrate 2, and the thin film transistor(TFT) 8 is composed of the thin film silicon layer 10, an insulation film 11 covering that and a gate electrode 12 formed on the film 11. Then, the metallic wiring layers 22, 23 becoming a light shield metallic layer are formed upward the TFT 8, and the reflection preventive film 24 is provided between the metallic wiring layers 22, 23 and the inter-layer insulation layers 14, 15. By such a constitution, since the reflection preventive film 24 is provided on the interface between the metallic wiring layers 22, 23 and the inter-layer insulation layers 14, 15, the optical leakage current of a pixel transistor is reduced, and the image display of the high contrast and quality is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an active matrix type liquid crystal display device using a TFT (thin film transistor).

[0002]

2. Description of the Related Art In recent years, an active matrix type liquid crystal display device using a TFT (thin film transistor) as a pixel switching element has been applied to a light valve of a projector (projection device).

[0003]

As described above, when a liquid crystal display device is used for a projector, strong light is generated by T.
When light enters the FT, a light leak current is generated in the TFT, and the image potential may be degraded, for example, the effective potential of the pixel signal may be reduced, or the contrast of the display screen may be reduced.

The generation of the light leakage current occurs when the illumination light is reflected, diffracted, or scattered inside the liquid crystal display device, and as a result, enters the TFT.

FIG. 5 is a schematic cross-sectional view of a main part of a conventional liquid crystal display device. In the liquid crystal display device 50, a thin silicon layer 58 is formed on a first insulating transparent substrate (glass substrate) 51, and the thin silicon layer 58, an insulating film 59 covering the thin silicon layer 58, and a gate formed thereon are formed. The electrode 60 constitutes a thin film transistor (TFT) 57. One electrode 61 of the storage capacitor Cs is formed on the other portion of the thin film silicon layer 58 where the thin film transistor 57 is not formed, and this electrode 61, the insulating film 59, and the portion of the thin film silicon layer 58 facing the electrode 61 are formed. These form the storage capacitance element Cs.

One side of the thin film transistor 57 (left side in the figure)
Is contacted with a signal line 71 made of a metal wiring layer,
On the opposite side (right side in the figure), a wiring layer 72 made of the same metal wiring layer as the signal line 71 is contacted. The wiring layer 72 extends to the right in the drawing and is electrically connected to the pixel electrode 53 patterned for each pixel via an upper wiring layer 74 composed of an upper metal wiring layer.

A light-shielding metal layer 73 is formed above the thin film transistor 57 so that light does not enter the thin film transistor 57 from above. FIG.
Among them, 62 and 63 are interlayer insulating layers made of, for example, an oxide film;
Reference numeral 4 denotes a passivation film made of, for example, a nitride film, and 65 denotes a flattening insulating layer made of a resin or the like.

Thus, the thin film transistor 57 is formed on the first insulating transparent substrate 51, and the pixel electrode 53 is formed on the surface.
Are formed, and a counter substrate 72 on which a counter electrode 54 is formed on the surface of a second insulating transparent substrate (glass substrate) 52, and the liquid crystal molecules 56 are dispersed therebetween. The liquid crystal display device 50 is configured by enclosing the liquid crystal layer 55 thus formed.

In the liquid crystal display device 50 shown in FIG. 5, light incident from above is shielded (reflected) by the light-shielding metal layer 73 to prevent the light from entering the thin film transistor 57 and is caused by light incident from above. The above-described light leakage current can be reduced.

However, in this case, the light incident on the signal line 71 passes through the path of the upper surface of the signal line 71-the lower surface of the light-shielding metal layer 73-the thin film transistor 57 as shown by the arrow in FIG. 71, 73 and interlayer insulating layer 6
In some cases, the light may be reflected at the interface with 3, 64 and enter the thin film transistor 57.

As described above, light leakage current may be caused by reflection at the interface between layers. In addition, some of the incident light is incident obliquely on the substrate surface, and another light is refracted when passing through the liquid crystal molecules 56. May not be able to be reduced.

The problem of the occurrence of the light leakage current becomes more remarkable as the brightness of the projector increases in the future.
There is a need to sufficiently reduce the light leakage current, and this is a major problem for liquid crystal display devices.

In order to solve the above-mentioned problems, the present invention provides a liquid crystal display device capable of displaying a high-contrast and high-quality image by preventing the occurrence of a light leakage current. is there.

[0014]

According to the liquid crystal display device of the present invention, a thin film transistor is formed on an insulating transparent substrate.
An antireflection film is provided between a metal wiring layer and an interlayer insulating layer.

According to the configuration of the present invention described above, since the antireflection film is provided between the metal wiring layer and the interlayer insulating layer, light is reflected at the interface between the metal wiring layer and the interlayer insulating layer. For this reason, light can be prevented from entering the thin film transistor.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a liquid crystal display device in which a thin film transistor is formed on an insulating transparent substrate and an antireflection film is provided between a metal wiring layer and an interlayer insulating layer.

Further, according to the present invention, in the above liquid crystal display device, the antireflection film is made of a metal oxynitride film.

Further, according to the present invention, in the above liquid crystal display device, the antireflection film is made of a TiON film.

Further, according to the present invention, in the liquid crystal display device described above, an antireflection film is provided only on the interface of the metal wiring layer on the semiconductor layer side constituting the thin film transistor.

Further, according to the present invention, in the above liquid crystal display device, an antireflection film is provided on both upper and lower interfaces of the metal wiring layer.

According to the present invention, there is provided the liquid crystal display device, wherein the metal wiring layer has a thickness of 50 nm or more and 800 nm or less.
1 film or an alloy film mainly composed of Al.

According to the present invention, in the above liquid crystal display device, the thickness of the antireflection film is 10 nm or more and 100 nm or less.

According to the present invention, in the above liquid crystal display device, the antireflection film is made of a metal nitride film.

According to the present invention, in the above liquid crystal display device, the antireflection film is made of a TiN film.

Further, according to the present invention, in the liquid crystal display device, the anti-reflection film is removed from the contact hole.

Further, the present invention provides the above-mentioned liquid crystal display device, wherein at least a part of the metal wiring layer is electrically connected to an electrode constituting a storage capacitor.

According to the present invention, in the above liquid crystal display device, the metal wiring layer is formed of a first portion electrically connected to an electrode constituting the storage capacitor, and the same material as the first portion; And at least an insulated second portion, and the second portion is electrically connected to a lead wiring layer and a pixel electrode of the thin film transistor.

FIG. 1 is a schematic sectional view of a main part of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a schematic plan view of a main part of the liquid crystal display device 1, and FIG. 3 is a block diagram of a circuit configuration.

This liquid crystal display device 1 has a liquid crystal layer (liquid crystal layer) having liquid crystal molecules 7 between a TFT substrate 19 on which a TFT (thin film transistor) 8 for controlling a pixel potential is formed and a counter substrate 20 facing the TFT substrate 19. LC) 6 is enclosed.

First, the structure of the TFT substrate 19 will be described.
As shown in FIG. 1, a thin silicon layer 10 is formed on an interlayer insulating layer 9 formed on a first insulating transparent substrate 2,
A thin film transistor (TFT) 8 is constituted by the thin film silicon layer 10, the insulating film 11 covering the thin film silicon layer 10, and the gate electrode 12 formed thereon.

The thin film transistor 8 of the thin film silicon layer 10
In the other portion where is not formed, one electrode of the storage capacitor element Cs, that is, a storage capacitor electrode (Cs electrode) 13 is formed, and this electrode 13 is opposed to the insulating film 11 and the electrode 13 of the thin film silicon layer 10. The storage capacitor element Cs is constituted by the portions.

A second metal wiring layer 22 constituting the signal line 31 is electrically connected to one side (left side in the figure) of the thin film transistor 8 through a contact hole 42, and is connected to the other side (right side in the figure). The same second metal wiring layer 22 as 31 is electrically connected through a contact hole 42. The metal wiring layer 22 extends to the right in the drawing and is electrically connected to the transparent pixel electrode 4 patterned for each pixel via an upper third metal wiring layer 23.

Then, above the thin film transistor 8,
A third metal wiring layer 23 serving as a light shielding metal layer is formed,
Light is prevented from entering the thin film transistor 8 from above. In FIG. 1, reference numerals 14 and 15 denote an interlayer insulating layer made of, for example, an oxide film, 16 denotes a passivation film made of, for example, a nitride film, and 17 denotes a flattening layer made of resin or the like. Thus, the TFT substrate 19 in which the thin film transistor 8 is formed on the insulating transparent substrate 2 is configured.

On the other hand, the counter substrate 20 is formed by forming the counter electrode 5 on the surface of the second insulating transparent substrate 3.

Then, as described above, the TFT substrate 19 and the opposing substrate 20 are opposed to each other, and the liquid crystal layer 6 in which the liquid crystal molecules 7 are dispersed is sealed therebetween, thereby forming the liquid crystal display device 1.

In the liquid crystal display device 1, the liquid crystal layer 6 operates in each pixel region corresponding to the pixel electrode 4 divided for each pixel. Actually, an image is displayed by changing the alignment direction of the liquid crystal molecules 7 of the liquid crystal layer 6 according to the strength of the electric field between the pixel electrode 4 and the counter electrode 5 and controlling light transmission. .

Then, as shown in FIG. 3, the liquid crystal layer 6 (L
C), the thin film transistor 8 and the storage capacitor element Cs to form a display pixel 40 surrounded by a broken line in the figure, and the display pixels 40 are arranged in a matrix. One electrode (pixel electrode 4) of the liquid crystal layer 6 and one electrode (electrode on the thin film silicon layer 10 side) of the storage capacitor Cs are connected to, for example, a drain of the thin film transistor 8. Further, the other of the thin film transistors 8, for example, the source is connected to the signal line 31,
The gate of the thin film transistor 8 is connected to the gate wiring 32. The signal of each display pixel 40 is controlled by turning on / off the thin film transistor 8 provided for each display pixel 40.

The other electrode (Cs electrode 13) of the storage capacitor element Cs is connected to a Cs (storage capacitor) wiring 33, and a fixed potential is applied to the Cs wiring 33 in common to all pixels.

Preferably, the same fixed potential is applied to the other electrode of the liquid crystal layer 6, that is, the counter electrode 5 and the Cs electrode 13. This is because TF is applied to the Cs electrode 13 as described later.
Since the third metal wiring layer 23 serving as a light-shielding film on T8 is connected, if different potentials are applied to the counter electrode 5 and the Cs electrode 13, the counter electrode 5 and the third metal wiring layer 23, an electric field is generated between the pixel electrode 4 and the counter electrode 5.
This is because there is a fear that the operation performed by the electric field may be affected.

Then, as shown in FIG.
3 is connected to a vertical scanning circuit 34, and the signal line 31 is connected to a horizontal scanning circuit 35 through a pixel signal supply switch 37 and a phase adjustment circuit 36. The vertical scanning circuit 34, the horizontal scanning circuit 35, the phase adjustment circuit 36, and the pixel signal supply switch 37 are supplied with power supply voltage, clock pulse,
A start pulse, a pixel signal, and the like are supplied.

The gate lines 32 are sequentially scanned by the vertical scanning circuit 34, and a voltage corresponding to the driving state of each pixel is sequentially applied to the signal line 31 in accordance with the scanning, thereby displaying the necessary pixels. Thus, one frame can be displayed in this manner. By repeating this, a moving image can be displayed.

Here, in the liquid crystal display device 1 of the present embodiment, particularly, in the second metal wiring layer 22 and the third metal wiring layer 23 formed on the TFT substrate 19, as shown in FIG. An antireflection film 24 is provided at the interface between the upper and lower interlayer insulating films 14 and 15. Thereby, for example, the light reaching the TFT 8 can be reduced by preventing the reflected light from being generated by the interface between the metal wiring layer and the interlayer insulating layer as indicated by the arrow in FIG. Can be prevented.

The material of the antireflection film 24 is, for example, TiO.
An N film can be used. Further, the thickness of the antireflection film 24 is preferably 10 nm or more and 100 nm or less.
If it is less than 10 nm or more than 100 nm, the reflectance of light having a wavelength of 400 nm to 600 nm, which is most desired to be absorbed, cannot be kept low, and if it exceeds 100 nm, the contact resistance increases, which is not preferable.

With the TiON film, for example, a wavelength of 400 nm
It is possible to effectively absorb light of up to 450 nm so as not to generate reflected light. In addition, the metal wiring layers 22 and 23
The TiON film provided on the upper side also serves as an etching stopper at the time of opening the contact hole, and has an effect of preventing stress migration caused by film stress at the time of forming the upper layer. Further, the contact resistance with ITO (indium tin oxide) generally used for the pixel electrode 4 is reduced, and good contact can be obtained.

The antireflection film 24 is not limited to a TiON film, but may be a TiN film, or a nitride or oxynitride film of a metal other than titanium.

In this embodiment, a first metal wiring layer 21 is formed below the thin film transistor 8 between the first insulating transparent substrate 2 and the interlayer insulating layer 9 thereon. . This first metal wiring layer 21 is
Has an effect of blocking light incident from the back surface direction, that is, from the first insulating transparent substrate 2 side, and is formed by, for example, a WSi / Si two-layer structure. Also, the first metal wiring layer 21
It is connected to the second metal wiring layer 22 at a portion (not shown), and a fixed potential, for example, a ground potential is applied to the scanning circuit portion other than the display portion.

The second metal wiring layer 22 is connected to the source and the drain of the thin film transistor 8 in the contact hole 42, and one of them is also used as the signal line 31. This second metal wiring layer 22 is formed, for example, by forming a TiON film as an anti-reflection film 24 on both upper and lower sides and forming a TiON / Al-S
It has a three-layer structure of i / TiON.

As shown in the plan view of FIG. 2, the third metal wiring layer 23 is provided so as to form a black matrix complementarily to the second metal wiring layer 22, and the TFT substrate 19
Are arranged so as to block incident light to the TFT 8 from above. The third metal wiring layer 23 is also used as the second metal wiring layer 2.
As in the case of No. 2, for example, it has a three-layer structure of TiON / Al-Si / TiON.

In the plan view of FIG. 2, the first metal wiring layer 21 and the pixel electrode 4 are omitted.

The second metal wiring layer 22 and the third metal wiring layer 23 are preferably formed by using an Al-based film having Al, for example, an Al film containing 1% of silicon (Al-Si film). Low wiring resistance can be ensured by low sheet resistance.

The metal wiring layers 22 and 23
Is preferably 50 nm or more and 800 nm or less. If the thickness is less than 50 nm, the wiring resistance of the metal wiring layers 22 and 23 increases, while if it exceeds 800 nm, the coverage and coverage of the interlayer film formed on the upper layer deteriorate, which is not preferable.

In place of the Al-Si film, Al, Al
Other Al-based or Cu-based metals or alloys, such as -Si-Cu, Al-Cu, and Cu, can also be used, and the wiring resistance can be similarly reduced.

Further, by providing a TiON film also on the Al-Si film to form a three-layer structure, it is possible to prevent stress migration caused by film stress.

The third metal wiring layer 23 is
As shown in FIG. 1, the upper TiON film is necessary for obtaining a good contact resistance with ITO in order to electrically connect with the pixel electrode 4 made of ITO.

When the upper wiring layer 74 is directly connected to the pixel electrode 53 as shown in FIG. 5, since the contact resistance between Al and ITO is high, an Al-based film should be used for the upper wiring layer 74. Can not. In contrast, when an Al-based film is connected to ITO via a TiON film as in the present embodiment, good contact resistance can be obtained, and the third
The wiring resistance can be reduced by using an Al-based film for the metal wiring layer.

Further, in the present embodiment, as shown in FIGS. 1 and 2, the third metal wiring layer 23 has a first portion 23A and a second portion 23B which are insulated from each other. It is composed. The first portion 23A is formed in a strip shape over the adjacent pixels as shown in FIG. 2, and the wiring (storage capacitance wiring) 33 of the Cs electrode 13 constituting the storage capacitance element Cs and the conductive layer in the contact hole 41 are formed. Are electrically connected via The second portion 23B corresponds to FIG.
As shown in FIG. 7, each pixel is formed in an island shape, and is electrically connected to the pixel electrode 4 and the second metal wiring layer 22 serving as a lead wiring layer of the thin film transistor 8.

By forming the third metal wiring layer 23 in this manner, by connecting with a low sheet resistance of the Al-based film of the third metal wiring layer 23, the storage capacitor wiring 33 made of polycrystalline silicon is formed. And the crosstalk can be reduced.

According to the above-described liquid crystal display device 1 of the present embodiment, the antireflection film 24 is provided at the interface between the second metal wiring layer 22 and the third metal wiring layer 23, so that the light of the pixel transistor 8 can be reduced. Leakage current can be reduced, and high-contrast and high-quality image display can be performed.

Further, by providing the first metal wiring layer 21 below the thin-film silicon layer 10, incident light from the lower side, that is, from the transparent insulating substrate 2 side can be blocked, so that a further light leakage current can be prevented. Can be prevented.

Further, by forming the second metal wiring layer 22 and the third metal wiring layer 23 as wirings having a three-layer structure, stress migration due to film stress can be prevented. Therefore, a highly reliable liquid crystal display device can be manufactured with a high yield.

Further, by electrically connecting the third metal wiring layer 23 and the Cs electrode 13 (Cs wiring 33) through the contact hole 41, the third metal wiring layer 23 is formed.
The Cs (storage capacitor) wiring 33 can be formed with a good sheet resistance, and crosstalk can be reduced.

Then, the third metal wiring layer 23 has a first portion 23 A electrically connected to the Cs wiring 33 and a second portion 23 B electrically connected to the pixel electrode 4.
Since these are formed in a three-layer structure of the same material, light leakage current is suppressed by anti-reflection and Cs wiring 3
3, it is possible to reduce the wiring resistance, and it is possible to obtain a good contact with a small contact resistance with the pixel electrode 4 by the material of the antireflection film 24.

The liquid crystal display device 1 of the present embodiment described above
For example, it can be manufactured as follows. First, a first insulating transparent substrate 2 made of, for example, glass
A polycrystalline silicon film having a thickness of, for example, 50 nm is formed thereon by LP-CVD (low pressure chemical vapor deposition), and a WSi film is formed thereon to have a thickness of 200 nm. Form. Then, these are patterned to form a first metal wiring layer 2 composed of a WSi / Si laminated film.
Form one.

Next, the first metal wiring layer 21 is covered, and SiO ₂ is deposited thereon as an interlayer insulating film 9 by AP-CVD.
A film is formed to a thickness of, for example, 600 nm by a (normal pressure chemical vapor deposition) method.

Next, as a first silicon layer, a thin film silicon layer 10 for forming a thin film transistor TFT is formed.
Is formed to a thickness of, for example, 75 nm by an LP-CVD method, and then silicon crystal grains are grown by heat treatment or the like.

Next, after patterning the thin-film silicon layer 10, the surface thereof is oxidized to form a thin insulating film 11 made of an oxide film, and then B (boron) is formed as a p-type impurity on the entire surface of the thin-film silicon layer 10. ) Is implanted at a low concentration.

Next, a mask is formed so as to hide the transistor portion, and As (arsenic) is ion-implanted at a high concentration as an n-type impurity into only the Cs (storage capacitor) portion of the thin-film silicon layer 10, and the storage capacitor element Cs Is formed as an electrode constituting one of the electrodes.

Next, a second layer is formed thereon by LP-CVD.
Is formed, and heat treatment is performed in a gas such as POCl ₃ to diffuse P (phosphorus) to lower the specific resistance.

Then, the second silicon layer is patterned into a predetermined pattern to form a gate electrode 12 and a Cs (storage capacitor) electrode 13.

Next, although not shown, a mask is formed so as to hide the pMOS formation portion for forming the nMOS, As is ion-implanted at a high concentration as an n-type impurity, and then the thin film transistor 8 and the vertical scanning circuit 34 are formed for forming the nMOS. Is masked so as to hide the nMOS portion in the peripheral circuit portion such as
B is ion-implanted at a high concentration as a type impurity.

Then, as shown in FIG. 4A, the AP-CV
The interlayer insulating layer 14 of phosphor silicate glass or the like is formed to a thickness of, for example, 600 nm by the method D. Thereafter, the crystallinity of the ion-implanted portion is restored by heat treatment.

Then, FIG. 4B
As shown in FIG. 5, a TiON film is formed as the antireflection film 24 to a thickness of, for example, 35 nm.

Next, after masking portions other than the contact holes by photography, as shown in FIG. 4C, the contact holes 42 are formed by etching the TiON film 24 and the interlayer insulating layer 14 in the contact hole portions.

In addition, although not shown, the first metal wiring layer 2
A contact hole is also opened for 1 and connected to an upper wiring layer in a later step.

Thereafter, as the second metal wiring layer 22, 1
An Al-Si layer containing% Si is formed to a thickness of, for example, 500 nm.

Further, a TiON film serving as an anti-reflection film 24 is continuously formed on the second metal wiring layer 22 to a thickness of, for example, 60 nm by a sputtering method. After this film formation, masking is performed by photolithography, and as shown in FIG. 4D, a three-layer structure of the TiON film 24 / Al—Si layer 22 / TiON film 24 is patterned by dry etching to form a three-layer structure. Form wiring.

Here, the T on the lower side of the second metal wiring layer 22 is
The iON film (thickness 35 nm) 24 has a wavelength of 400 nm to 4 nm.
It effectively absorbs 50 nm light, and the upper T
The iON film (thickness: 60 nm) 24 also functions as an etching stopper in etching when forming a contact hole with a later upper wiring.

Subsequently, an interlayer insulating layer 15 made of, for example, phosphorus silicate glass (PSG) is
A film is formed to a thickness of 00 nm.

Further, as the passivation film 16,
SiN is deposited to a thickness of, for example, 200 nm by a plasma CVD method. Next, the passivation film 16 is etched and removed from the contact portion with the pixel electrode 4, the pixel opening, that is, the portion where the TFT 8 is not formed, and the pad portion 38 (see FIG. 3) of the peripheral circuit. An opening is formed in the 38 interlayer insulating layer 15.

Thereafter, for example, a TiON film is formed as an anti-reflection film 24 on both upper and lower sides by a method similar to that of a wiring layer having a three-layer structure of a second metal wiring layer 22 and an anti-reflection film 24, for example, Al -A third metal wiring film 23 made of a Si film is formed, and is formed into a first portion 23 shown in FIG.
A and a pattern having a second portion 23B.

After the transistor characteristics are recovered by heat treatment, the surface is coated with, for example, an organic film as the flattening layer 17 to flatten the surface. Subsequently, in the contact portion for connecting to the pixel electrode 4, the planarizing layer 1 is formed.
7, a contact hole 18 is opened. At this time, a contact hole is also opened in the pad portion 38.

Next, ITO (indium tin oxide) for the pixel electrode 4 is formed into a film having a thickness of, for example, 70 nm by a sputtering method, and is patterned into a pattern divided for each pixel. Form. As a result, the pixel electrode 4 electrically connected to the wiring layer formed of the third metal wiring layer 23 in the previously opened contact hole 18 is formed.

Thus, a TFT substrate having the thin film transistor 8 formed on the transparent insulating substrate 2 is formed.

Thereafter, the transparent insulating substrate (opposite substrate) 3 having the opposing electrode 5 formed on the surface thereof is opposed to the TFT substrate, and the liquid crystal molecules 7 forming the liquid crystal layer (LC) 6 therebetween.
And the liquid crystal display device 1 can be manufactured.

In the above embodiment, the antireflection film 24 is provided on the upper and lower layers of the metal wiring layers 22 and 23. However, the antireflection film 24 is provided only on the lower side of the metal wiring layers 22 and 23. Is also good. In this case, although the effect is slightly lower than when the antireflection film 24 is formed on both the upper layer and the lower layer, it has the effect of reducing light reflected between the layers and suppressing light leakage current.

Further, an antireflection film may be provided on only one of the second metal wiring layer 22 and the third metal wiring layer 23. In this case, both metal wiring layers 22
And 23 have a slightly lower effect than when the antireflection film 24 is formed, but also have the effect of reducing light reflected between the layers and suppressing light leakage current.

The antireflection film 24 of the contact portion is
It may be removed as shown in the cross-sectional view of FIG. 1, and may be left if there is no problem in contact resistance. In the case where the anti-reflection film 24 below the second metal wiring layer 22 is left in the contact portion, unlike the process shown in FIG.
Is formed.

Further, it is possible to adopt a configuration in which the first metal wiring layer 21 for shielding the back surface provided below the semiconductor layer 10 constituting the thin film transistor 8 is not provided.

When a black matrix is provided on the counter substrate 3, light can be shielded by the black matrix, so that the third metal wiring layer 23 may not be formed.

In the above-described embodiment, the thin film transistor 8 is constituted by a planar thin film transistor in which the semiconductor layer 10 is formed horizontally and the gate electrode 12 is formed above the semiconductor layer 10, but an insulating film is formed on the gate electrode. The present invention can be similarly applied to a thin film transistor having another configuration such as an inverted staggered thin film transistor in which a semiconductor layer is formed to have a step corresponding to a gate electrode.

The liquid crystal display device of the present invention is not limited to the above-described embodiment, but may take various other configurations without departing from the gist of the present invention.

[0092]

According to the above-described liquid crystal display device of the present invention, by providing an antireflection film at the interface between the metal wiring layer and the interlayer insulating layer, the light leakage current of the pixel transistor can be reduced. It is possible to display a high-quality image with contrast.

When the wiring layer has a three-layer structure in which antireflection films are formed above and below the metal wiring layer, stress migration due to film stress can be prevented. Thus, a highly reliable liquid crystal display device can be manufactured with a high yield.

Further, when the light shielding film is provided on the substrate side below the semiconductor layer forming the thin film transistor, further light leakage can be prevented.

When at least a part of the metal wiring layer is electrically connected to the electrode forming the storage capacitor, the wiring of the electrode forming the storage capacitor is formed with a good sheet resistance of the metal wiring layer. By being able to form
The wiring resistance of this wiring can be reduced, and crosstalk can be reduced.

Further, the first portion electrically connected to the electrode forming the storage capacitor and the second portion electrically connected to the pixel electrode are formed of the same material to prevent reflection. It is possible to suppress the light leakage current and reduce the wiring resistance, and it is possible to obtain a good contact having a small contact resistance with the pixel electrode by using the material of the antireflection film.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a main part of the liquid crystal display device of FIG.

FIG. 3 is a block diagram showing a circuit configuration of the liquid crystal display device of FIG.

4A to 4D are process diagrams showing a manufacturing process of the liquid crystal display device of FIG.

FIG. 5 is a schematic sectional view of a main part of a conventional liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 2 1st insulating transparent substrate, 3 2nd insulating transparent substrate, 4 pixel electrode (display electrode), 5 counter electrode, 6 liquid crystal layer, 7 liquid crystal molecules, 8 TFT (thin film transistor), 9 , 14,15 interlayer insulating layer, 10
Thin silicon layer, 11 insulating film, 12 gate electrode, 1
3 Cs (storage capacitor) electrode, 16 passivation film, 17 planarization layer, 18, 41, 42 contact hole, 19 TFT substrate, 20 counter substrate, 21 first metal wiring layer, 22 second metal wiring layer, 23rd 3 metal wiring layer, 24 antireflection film, 31 signal line, 32 gate wiring, 33 Cs (storage capacitor) wiring, 34 vertical scanning circuit, 35 horizontal scanning circuit, 36 phase adjustment circuit, 3
7 image signal supply switch, 38 pad section, 40 display pixels, Cs storage capacitor

Continued on the front page F term (reference) 2H091 FA37Y GA13 LA17 LA30 MA07 2H092 GA17 GA25 GA34 JA24 JA26 JB69 KA04 KB24 MA05 MA06 MA07 NA22 NA28 RA05 5F110 AA06 AA18 BB01 BB04 CC02 CC07 DD13 DD24 FF02 FF23 GG02 GG13 GG01 GG13 GG13 GG32 HL03 HL06 HL12 HM18 NN03 NN04 NN24 NN25 NN27 NN35 NN40 NN42 NN43 NN45 NN48 NN54 NN72 PP38 QQ09 QQ19

Claims (12)

[Claims] 1. A liquid crystal display device comprising a thin film transistor formed on an insulating transparent substrate, wherein an antireflection film is provided between a metal wiring layer and an interlayer insulating layer. 2. The liquid crystal display device according to claim 1, wherein said antireflection film is made of a metal oxynitride film. 3. The liquid crystal display device according to claim 1, wherein the antireflection film is made of a TiON film. 4. The liquid crystal display device according to claim 1, wherein the antireflection film is provided only on the interface of the metal wiring layer on the semiconductor layer side forming the thin film transistor. 5. The liquid crystal display device according to claim 1, wherein the antireflection film is provided on both upper and lower interfaces of the metal wiring layer. 6. The method according to claim 1, wherein the metal wiring layer has a thickness of 50 nm or more and 80
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed of an Al film having a thickness of 0 nm or less or an alloy film mainly containing Al. 7. The liquid crystal display device according to claim 1, wherein the thickness of the antireflection film is 10 nm or more and 100 nm or less. 8. The liquid crystal display device according to claim 1, wherein the antireflection film is made of a metal nitride film. 9. The liquid crystal display device according to claim 1, wherein the antireflection film is made of a TiN film. 10. The liquid crystal display device according to claim 1, wherein the antireflection film is removed in a contact hole portion. 11. The liquid crystal display device according to claim 1, wherein at least a part of the metal wiring layer is electrically connected to an electrode forming a storage capacitor. 12. A first portion in which said metal wiring layer is electrically connected to an electrode forming said storage capacitor,
And at least a second portion formed of the same material as the first portion and insulated from the first portion, and the second portion is electrically connected to the extraction wiring layer and the pixel electrode of the thin film transistor. The liquid crystal display device according to claim 11, wherein: