JPH08194230A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE: To eliminate disconnection and short circuiting defects and to improve a yield by improving the adhesion of a stepped part with respect to a transparent conductive film. CONSTITUTION: A nearly randomly oriented polycrystalline indium tin oxide(ITO) film 101 having the ratio of the X-ray diffraction peak intensity of the (400) face to the (222) face in the range of 25 to 75% is used as the transparent conductive film of the liquid crystal display device. Since this film has a film structure densely packed with crystal grains of a uniform size, the interior of the crystal grains and grain boundaries are uniformly etched at the time of patterning the film by a wet etching method, by which a well etched end shape 103 of a forward taper is obtd. Then, the good adhesion of the upper layer film is assured in the case the other film bestrides the difference in level of the transparent conductive film. The penetration of an etchant in the transverse direction of the stepped part is prevented even when the transparent conductive film bestrides the difference in level of the other film and, therefore, the stepwise breakage from the etched ends of the pattern is lessened and the adhesion of the transparent conductive film itself is assured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device having a yield improved by using a transparent conductive film having a good shape of an etching end portion and a step portion and a liquid crystal display device thereof. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art In a liquid crystal display device, a transparent conductive film is used as a wiring, a pixel electrode, or a part of a terminal. As a method of patterning the transparent conductive film, a method of forming a transparent conductive film, forming a resist pattern by photolithography, and then patterning the film by wet etching is used.

As the transparent conductive film, an indium tin oxide (ITO) film in which tin oxide is added to indium oxide is usually used. The indium tin oxide film is generally formed by a sputtering method, but it is known that the properties of the film are likely to change depending on the difference in the sputtering method, the sputtering power, the gas pressure, the substrate temperature, the kind of the atmospheric gas, and the like.

The difference in the film quality of the transparent conductive film causes variations in the etching rate when the film is wet-etched, but since the factor that determines the optimum etching rate is not clear, the patterning of the transparent conductive film is performed. A defect occurs,
It has been known that the yield of liquid crystal display devices decreases.

Regarding the wet etching of the transparent conductive film, for example, in JP-A-3-166518, the transparent conductive film is formed below the transition temperature, patterned in an amorphous state, and then annealed at the transition temperature or higher. It has been proposed to increase the etching rate of the film by performing polycrystallization to perform patterning.

The indium tin oxide film has a cubic bixbyite type structure, which is a crystal structure of indium oxide.
(ASTM Card 6-0416) and Japanese Patent Laid-Open No. 4-48516 propose that a polycrystalline film with a specific orientation is formed to increase the etching rate of the film and perform patterning.

[0007]

As in the above-mentioned conventional example,
The use of an amorphous film or a polycrystalline film with a specific orientation increases the etching rate of the transparent conductive film.

However, if the film etching rate is actually increased, it becomes difficult to control the etching time.
It is rather difficult to form a transparent conductive film pattern with good reproducibility.

Further, in the case of patterning in an amorphous state as in the above-mentioned conventional example, there is a problem that if the film contains a crystal component even a little, the etching becomes non-uniform and a residue is generated after the etching.

Similarly, when a polycrystalline film having a specific orientation is used, there is a problem that the etching progresses nonuniformly along the grain boundaries. Since such a film is etched non-uniformly in the film thickness direction and the lateral direction of the film, the shape of the etching end portion becomes sharp in the film thickness direction, and in extreme cases, the reverse hang of the overhang is performed. -It becomes a par shape.

Further, the unevenness of the film in the lateral direction becomes severe, and the variation in the finished size of the pattern also becomes large. The patterning failure of the transparent conductive film also induces the sticking failure of the film laminated thereon. In a liquid crystal display device, particularly a liquid crystal display device using an active matrix substrate, a transparent conductive film is used as a pixel electrode, a wiring, or a part of these terminals, but it is directly on the transparent conductive film pattern. Alternatively, at a place where wiring, a semiconductor film, or the like is connected or intersects via an insulating film, the step shape of the etching end portion of the transparent conductive film pattern serving as the lower layer has a shape that rises in the cross-sectional direction of the film as described above. In such a case, the wiring around the upper layer, the semiconductor, and the insulating film have a poor step around the edges of the transparent conductive film pattern, resulting in disconnection or short circuit.

On the contrary, even when the transparent conductive film pattern crosses over the step portion of the wiring, the semiconductor film, the insulating film, or the laminated film of the insulating film and the semiconductor film, the transparent conductive film itself at the step portion is not formed. Due to poor attachment, a step break was caused in the lateral direction from the etching end of the transparent conductive film pattern intersecting the step portion, resulting in a disconnection defect of the transparent conductive film. Therefore, in the above-mentioned conventional example, no consideration is given to the shape of the etching end of the transparent conductive film pattern and the surrounding of the transparent conductive film pattern itself at the step portion, and as a result, This has been a cause of lowering the yield of the liquid crystal display device used. In addition, since the basic properties of the transparent conductive film such as the specific resistance and the transmittance are deteriorated in the film in the amorphous state, the film must be annealed after the etching to be polycrystallized, which complicates the process. It was

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device which solves the above-mentioned problems and improves the yield, and a manufacturing method thereof.

[0014]

In order to achieve the above object, the present invention is characterized in that the following means are taken.

(1) In a liquid crystal display device having a transparent conductive film pattern provided on at least a part thereof, the transparent conductive film is a polycrystalline indium tin oxide (ITO) film in which tin oxide is added to indium oxide. Each crystal grain was a columnar crystal, and the crystal orientation of each crystal grain was not biased in a specific direction, that is, a random orientation was used.

(2) In the liquid crystal display device according to the above (1), the transparent conductive film is random within a range of 25 to 75% in the X-ray diffraction peak intensity ratio of the (400) plane to the (222) plane. An oriented polycrystalline indium tin oxide (ITO) film was used.

(3) In the liquid crystal display device of the above (1) and (2), the film thickness of the transparent conductive film is 30 to 500 nm.

(4) In the liquid crystal display device according to any one of (1) to (3) above, the step shape at the end of the transparent conductive film pattern is changed to a tape shape.
The taper was formed into a regular taper shape with a corner angle of 45 degrees or less.

(5) In the liquid crystal display device according to the above (1) to (4), the crystal grain size of the transparent conductive film is set to 17 to 23 nm.

(6) In the liquid crystal display device according to the above (1) to (5), the unevenness of the surface of the transparent conductive film is 30 with respect to the film thickness.
% Or less.

(7) In the liquid crystal display device according to the above (1) to (6), the amount of tin oxide added to the transparent conductive film is 3 to 12% by weight.

(8) In the liquid crystal display device according to the above (1) to (7), the transparent conductive film is used as a part of a lead-out terminal for connection with a wiring, a pixel electrode, or an external drive circuit.

(9) In the liquid crystal display device according to the above (1) to (8), the transparent conductive film pattern is formed in a part of the liquid crystal display device.
The insulating film is laminated on at least a part of the screen.

(10) In the liquid crystal display device according to the above (1) to (8), a metal film, an alloy film, or a metal silicide is formed on at least a part of the transparent conductive film pattern in a part of the liquid crystal display device. The film has a structure in which the films are laminated directly or via an insulating film.

(11) In the liquid crystal display device of the above (1) to (8), a semiconductor film is laminated on at least a part of the transparent conductive film pattern in a part of the liquid crystal display device.

(12) In the liquid crystal display device according to the above (1) to (8), the transparent conductive film pattern is provided in a part of the liquid crystal display device so as to cross over at least a part of the step portion of the insulating film. It has a laminated structure.

(13) In the liquid crystal display device according to the above (1) to (8), at least a part of the stepped portion of the metal film, the alloy film, or the metal silicide film is directly or insulated from a part of the liquid crystal display device. The transparent conductive film pattern is laminated so that the transparent conductive film pattern is laminated over the film.

(14) In the liquid crystal display device according to the above (1) to (8), at least a part of a step portion of a structure in which a semiconductor film or a semiconductor film is laminated on an insulating film is formed on a part of the liquid crystal display device. The transparent conductive film pattern
It has a laminated structure.

(15) In the liquid crystal display device according to the above (12) to (14), the shape of the step portion over which the transparent conductive film pattern is overlaid is a forward taper having a taper angle of 90 degrees or less. Shaped.

(16) In the liquid crystal display device according to any one of (9) to (15), as the metal film, alloy film or metal silicide film, a metal film such as Al, Cr, Ta, Ti or Mo, an alloy film, A metal silicide film or a laminated film of these is used as the insulating film such as a silicon nitride film, a silicon oxide film, or an oxide film formed by oxidizing a part of the surface of the metal, or a laminated film of these is used as the semiconductor film. Amorphous silicon or polycrystalline silicon film was used, respectively.

(17) In the method for manufacturing a liquid crystal display device according to (1) to (16) above, the transparent conductive film is patterned by a wet etching method.

(18) In the method of manufacturing a liquid crystal display device according to the above (17), a ferric chloride / hydrochloric acid solution or a halogen acid such as hydrochloric acid, oxalic acid or hydroiodic acid is used as an etchant for the wet etching method. Alternatively, aqua regia was used.

[0033]

By using the polycrystalline indium tin oxide film having the film structure of (1), (2), (3), (5), (6) and (7) as a transparent conductive film of a liquid crystal display device, The good etching end shape of the above (4) can be easily obtained.

Further, according to the constitution (8) in which the polycrystalline indium tin oxide film of the above (1) to (7) is used as the transparent conductive film, the circumference of the step portion of the transparent conductive film can be improved. It is possible to obtain a liquid crystal display device which can reduce disconnection of wiring and a short circuit defect and has a high yield.

Specifically, according to the above configurations (9) to (16), even when the insulating film, the wiring, and the semiconductor are laminated on the transparent conductive film pattern, the transparent conductive film pattern end portion is formed. In this case, the stepped area is improved, and a liquid crystal display device without a short circuit or a disconnection defect can be obtained.

Further, even when the transparent conductive film pattern crosses over the step portion of the insulating film, the wiring, the semiconductor, and the laminated film of the insulating film and the semiconductor film, the surrounding of the transparent conductive film itself at the step portion. As a result, it is possible to obtain a liquid crystal display device in which there is no disconnection defect of the transparent conductive film.

By patterning the transparent conductive film by the methods (17) and (18), the liquid crystal display devices (1) to (16) can be obtained with a high yield.

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

The inventor of the present invention investigated the relationship between the film structure of the indium tin oxide film and the etching behavior, and found that there was a strong correlation between them. Prior to the description of the examples, first, referring to FIGS. 1 to 4, the orientation of the film (dependence of the growth orientation of the final on the substrate surface),
The facts newly found regarding the relationship between the crystal grain size, the film structure such as surface irregularities, the etching edge shape, the etching rate, and the side etching amount will be described.

FIG. 1 summarizes the relationship between the film structure of polycrystalline indium tin oxide and the shape of the etching edge, focusing on the film orientation, specifically, the peak intensity ratio obtained by X-ray diffraction spectrum measurement. The results are shown. The polycrystalline indium tin oxide film was formed by changing the conditions in the RF sputtering method or the DC sputtering method. For example,
The target used was indium tin oxide in which the amount of tin oxide added was 3 to 12% by weight, and the sputtering gas used was Ar or approximately 5% oxygen-added Ar. Sputter power is 100
˜1000 W, sputter gas pressure 2 to 10 mTorr, and substrate temperature 180 to 350 ° C. Film thickness is 30 ~ 500nm
Is. A ferric chloride / hydrochloric acid solution, a halogen acid such as hydrochloric acid, oxalic acid, or hydroiodic acid, or aqua regia was used as the etchant. In the surface shape and sectional shape of the etching end portion in FIG. 1, reference numeral 101 is a polycrystalline indium tin oxide film, 102 is a glass substrate, and 103 is a portion showing a good etching end shape.

The etching of the polycrystalline indium tin oxide film proceeds in the crystal grains and along the crystal grain boundaries. When the etching along the crystal grain boundaries becomes dominant, the film thickness direction and the lateral direction of the film (film Since a non-uniform etching occurs in the direction perpendicular to the thickness direction), a good etching end shape cannot be obtained. Specifically, when the (222) orientation of the film becomes strong (region A), the (222) oriented particles cause abnormal growth in a projection shape. In such a film, the etching progresses along the grain boundaries, and the abnormal growth particles 104 are desorbed, so that the etching becomes non-uniform and a good etching end shape cannot be obtained. The cross section of the etching end has an inverted taper shape. Further, due to the abnormal growth particles 104 in the shape of protrusions, the unevenness of the film surface becomes 30% or more of the film thickness, and the transmittance is lowered.

On the other hand, when the (400) orientation of the film becomes strong (region C), the film has clear crystal grain boundaries 105. In this case, the etchant permeates along the crystal grain boundaries, causing abrupt peeling etching in crystal grain units, making it impossible to control the etching edge shape at all. At the etching end of the pattern, fine crack-shaped irregularities 106 are generated in the lateral direction, and the cross section of the end also has an inverted taper shape.

On the contrary, by using a polycrystalline indium tin oxide film in which the crystal orientation of each crystal grain is not biased in a specific direction with respect to the substrate as the transparent conductive film, that is, the above-mentioned transparent indium tin oxide film is used. It can be seen that such abnormal etching can be prevented and a good etching edge shape 103 can be obtained.

The degree of random orientation of such a transparent conductive film is determined by the X-ray diffraction peaks of the (400) plane with respect to the (222) plane.
The intensity ratio ((400) / (222)) is in the range of 25 to 75% (region B). Within this range, a film structure is formed in which crystal grains of uniform size are densely packed, so that the inside of the crystal grains and the crystal grain boundaries are uniformly etched, and a good etching edge shape 103 is obtained. In this case, the etching edge shape 103 is a forward taper having an inclination angle of 45 degrees or less.

Further, since the etchant is not soaked in the lateral direction along the crystal grain boundaries, the crack-like unevenness 106 generated at the pattern end is also reduced. Adhesion to the glass substrate 102 as the base is also good. The (400) / (222) peak intensity ratio of the powder standard sample showing completely random orientation is 30% (ASTM Card 6-0416), and the range of the present invention showing a good etching edge shape 103. (Region B) is in the range of 0.8 to 2.5 times the peak intensity ratio of the standard sample.

Further, the intensity ratio of the X-ray diffraction peak to the (222) plane other than the (400) plane, for example, the (440) plane to the (222) plane is X-ray of the (400) plane to the (222) plane. It was additionally confirmed that it was constant in the vicinity of 30 to 40% regardless of the magnitude of the line diffraction peak intensity ratio, and that it showed almost random orientation. The (440) / (222) peak intensity ratio of the powder standard sample showing completely random orientation was 35% (AS
TM Card 6-0416), the range of 30 to 40% corresponds to a peak strength ratio 0.85 to 1.15 times that of the standard sample.

FIG. 2 shows the relationship between the (400) / (222) peak intensity ratio and the crystal grain size. A film having a (400) / (222) peak intensity ratio within the range of the present invention (region B) has a crystal grain size of 1
It is within the range of 7 to 23 nm, and shows a film structure in which crystal grains of uniform size are densely packed.

FIG. 3 shows the relationship between the (400) / (222) peak intensity ratio and the film etching rate, and FIG. 4 shows (400) / (22).
2) The relationship between the peak intensity ratio and the side etch amount is shown. In these figures, within the scope of the present invention (region B)
The etching rate of the film is 1 to 4 nm / s when a ferric chloride / hydrochloric acid solution (38% FeCl ₃ : 36% HCl = 1: 1) at 50 ° C. is used. Side etch amount is 120
s is 1 μm or less. If the thickness is out of this range, the etching rate of the film and the amount of side etching increase rapidly, and the dimensional accuracy of the pattern also decreases sharply.

As described above, the relationship between the film structure and the etching behavior of the indium tin oxide film described with reference to FIGS. 1 to 4 does not depend on the thickness of indium tin oxide and the amount of tin oxide added within the range of investigation. . For example, the addition amount of tin oxide is 3 to
It was confirmed that the same etching behavior is exhibited if the film orientation is the same even in the range of 12% by weight and the film thickness of 30 to 500 nm.

Further, a ferric chloride / hydrochloric acid solution, a halogen acid such as hydrochloric acid, oxalic acid, hydroiodic acid, or aqua regia was used as an etchant, but the absolute value of the etching rate was changed, but it was obtained. It was confirmed that the etching behavior did not depend on the type, composition and concentration of the etchant, and the liquid temperature.

In the following, referring to FIGS. 5 to 17, taking an active matrix substrate as an example, in a liquid crystal display device,
An example of application of the present invention to the surroundings of each step portion involving the transparent conductive film will be described.

FIG. 5 is a perspective view showing the structure of a color liquid crystal display device in which the above transparent conductive film is used as a part of an active matrix substrate. In the figure, on the glass substrate 102, the pixel electrode 501 formed of the transparent conductive film and the thin film transistor (T
FT) 502, scanning wiring 503 for transmitting and holding a signal for driving the TFT 502 to each TFT 502,
The signal wiring 504 and the like are formed to form an active matrix substrate 505.

On the surface of the active matrix substrate 505, a counter electrode 507 is colored through a liquid crystal layer 506.
A filter 508 is formed, and an insulating substrate 509 is formed on the color filter 508. The glass substrate 1
02 and the insulating substrate 509, a polarizing plate 510 is formed on the main surface exposed to the outside. In the active matrix substrate having such a configuration, color display is possible by applying a voltage to the pixel electrode 501 via the TFT 502 and adjusting the light from the light source.

In this embodiment, since the transparent conductive film of the present invention is used for the pixel electrode 501, it is possible to improve the circumference of the step portion where the pixel electrode 501 is involved. In this case, there are roughly two types of attachments, and the following improvement effects can be obtained in both of them, and therefore disconnection and short circuit defects at the step portion can be reduced. Even when another film gets over the step of the pixel electrode 501,
Since the pixel electrode 501 has a film structure in which crystal grains of a uniform size are densely packed, the inside of the crystal grains and the crystal grain boundaries are uniformly etched, and the etching end portion of the pixel electrode 501 is a normal taper. A good etching edge shape is obtained. Accordingly, even when another film crosses over the step of the pixel electrode 501, good coverage can be secured. On the contrary, even when the pixel electrode 501 crosses the step of another film, the pixel electrode 501 has a film structure in which crystal grains of uniform size are densely packed, and the crystal grains and the crystal grain boundaries are uniformly etched. Therefore, it is possible to prevent the etchant from penetrating in the lateral direction along the crystal grain boundaries, and therefore, even in a step portion where grain boundaries are likely to occur, such as a crossing portion of patterns.
It is possible to reduce disconnection of the pixel electrode 501 from the etching end. Adhesion with the base is also improved, and the periphery of the pixel electrode 501 itself can be secured in the step portion.

Next, a specific example of an embodiment in which the transparent conductive film of the present invention is applied to the periphery of each step portion in which the transparent conductive film participates in the active matrix substrate described in FIG. 5 will be described.

FIG. 6 shows an embodiment of a cross section of one pixel of an active matrix substrate using a reverse stagger type TFT as a switching element. In FIG. 6, the glass substrate 102
A gate electrode 601 and a pixel electrode 501 made of the transparent conductive film of the present invention are formed on a part of the upper portion, and a gate insulating film 602 is formed on the entire surface thereof. On the gate electrode 601,
An amorphous silicon film 603 to be a channel semiconductor layer of the TFT 502 via an gate insulating film 602 and an electrode layer 604 made of an amorphous silicon film doped with impurities such as phosphorus for compensating for a contact are formed. Stacked islands are formed. A source / drain electrode 605 is formed on a part of the island. Using the pattern of the source / drain electrode 605 as a mask, a part of the electrode layer 604 made of an amorphous silicon film doped with impurities is removed to form a channel portion 606 of the TFT 502.

Further, the gate insulating film 60 on the pixel electrode 501.
2 is provided with an opening 607 in a part thereof.
Through the pixel electrode 501 and the source / drain electrode 605.
Is connected.

Further, the TFT 502 and the pixel electrode 501
A passivation film 608 is formed so as to cover the entire upper surface. The gate electrode 601 and the source / drain electrode 605 are extended portions, respectively, for the scanning wiring 50 in FIG.
3, signal wiring 504. The gate electrode 601 and the source / drain electrode 605 are formed by, for example, sputtering,
Alternatively, Al, Cr, Ta, Ti formed by a vapor deposition method,
It is composed of a metal such as Mo, an alloy, a metal silicide, or a laminated film thereof.

The gate insulating film 602 and the passivation film 608 are composed of an insulating film such as a silicon nitride film formed by plasma CVD or a sputtering method, or a silicon oxide film. Gate insulating film 602
May be formed by oxidizing part of the surfaces of the gate electrode 601 and the scanning wiring 503.

Further, these oxide film and silicon nitride film,
Alternatively, it may be formed of a laminated film with a silicon oxide film or the like.

Wiring or gate channel semiconductor layer 60
3 and the electrode layer 604 are composed of, for example, an amorphous silicon film formed by a plasma CVD method or a polycrystalline silicon film polycrystallized by heat treatment.

In the present embodiment, the shape 609 of the etching end portion of the pixel electrode 501 is a good etching end shape of the normal taper, and therefore the source / drain electrode is formed through the gate insulating film 602. The area around the stepped portion 605 having a step is improved, and disconnection failure due to step breakage at the edge can be prevented.

Also, in the etching end portion 610 on the opposite side of the pixel electrode 501, the gate insulating film 602 and the passivation film 608 are better provided with steps, so that a short circuit failure due to dielectric breakdown at the end portion is prevented. It can be prevented.

FIG. 7 shows the scanning wiring 5 in the embodiment of FIG.
03 shows an example of a cross-sectional configuration of the intersection of the signal line 03 and the signal wiring 504. In the figure, the scanning wiring 503 and the signal wiring 504
Are orthogonal to each other with the gate insulating film 602 interposed therebetween.

FIG. 8 shows the scanning wiring 5 in the embodiment of FIG.
3 shows an example of a cross-sectional configuration of a lead-out terminal portion for connection with an external drive circuit of No. 03. The exposed portion of the scanning wiring 503 is
Since it is easily corroded when exposed to the air, the exposed part is covered with the transparent conductive film. Specifically, the scanning wiring 503 is formed on a part of the glass substrate 102, and the protective electrode 801 made of the transparent conductive film of the present invention is formed thereon so as to cover the exposed portion of the terminal.

The protective electrode 801 is formed at the same time as the pixel electrode, and has a gate insulating film 602 and a passivation film 60.
8 is a protective electrode 80 so that the protective electrode 801 is exposed.
A part on 1 is removed by etching.

Even at the end step portion 802 of the scanning wiring 503, the surrounding of the protective electrode 801 made of a transparent conductive film is secured, so that the terminal covering is completely protected, and therefore the terminal portion of the scanning wiring 503 due to corrosion is formed. It is possible to prevent disconnection at.

FIG. 9 shows the signal wiring 5 in the embodiment of FIG.
The example of a cross section of the terminal part 04 is shown. For the same reason as the configuration of the terminal portion of the scanning wiring 503 described in FIG. 8, the signal wiring 504 cannot be exposed. Therefore, when forming the scanning wiring 503, the lead electrode 901 for leading the signal wiring is formed at the terminal portion of the signal wiring 504. The signal wiring 504 is connected to the extraction electrode 901,
The lead electrode 901 is relayed and exposed to the outside. On the surface of the extraction electrode 901, the scanning wiring 50 described in FIG.
The protective electrode 801 made of the transparent conductive film of the present invention is formed in the same manner as in the configuration of the terminal portion 3 of FIG.

Stepped portion 902 at the end of the extraction electrode 901
As in the case of FIG. 8, the surroundings of the protective electrode 801 are secured in the portion as well, so that disconnection at the terminal portion of the signal wiring 504 due to corrosion can be prevented.

Further, since a good end shape is ensured in the step portion of the etching end portion of the protective electrode 801, even in the portion 903 where the signal wiring 504 is connected to the lead electrode 901, the gate insulating film 602 is interposed. It is possible to prevent disconnection due to disconnection of the signal wiring 504.

In the embodiment shown in FIGS. 6 to 9, the pixel electrode 501 is used.
Is the same layer as the gate electrode 601 and is formed in the lowermost layer, but the pixel electrode 501 may be formed in a layer above the gate electrode 601.

FIG. 10 shows an embodiment in which the pixel electrode 501 is in the same layer as the amorphous silicon film 603 which becomes the channel semiconductor layer. In this case, the source / drain electrode 605 directly goes over the step 1001 at the etching end of the pixel electrode 501.

FIG. 11 shows an embodiment in which the pixel electrode 501 is on the upper layer of the source / drain electrode 605. In this case, contrary to the embodiment of FIG. 10, the source / drain electrode 6
The pixel electrode 501 directly crosses over the step 1101 of 05. In any of the embodiments shown in FIGS. 10 and 11, by applying the transparent conductive film of the present invention,
It is possible to prevent disconnection of the drain electrode 605 or the pixel electrode 501.

In the embodiments of FIGS. 6 to 11, the transparent conductive film of the present invention is used as the pixel electrode 501 and the protective electrode 80 of the terminal portion.
Although it is applied only to No. 1, it may be applied to wiring.

FIG. 12 shows a pixel electrode 501 and, for example, a source electrode.
This is an example in which the transparent conductive film of the present invention is applied by also using the drain / electrode 605 and the signal wiring 504. FIG.
2, 1201 is a pattern in which the pixel electrode 501 and the source / drain electrode 605 are integrated. In this case, the transparent conductive film pattern 1201 is an end of an island pattern in which an amorphous silicon film 603 to be a channel semiconductor layer and an electrode layer 604 made of an amorphous silicon film doped with impurities are stacked. While directly overcoming the portion 1202, the end portion 1203 of the gate electrode 601 is connected to the gate insulating film 602,
Amorphous silicon film 603 to be a channel semiconductor layer, and electrode layer 6 made of an amorphous silicon film doped with impurities
You will get through 04. By using the transparent conductive film also as the wiring, the surrounding portion of the step involving the transparent conductive film is increased, but by applying the transparent conductive film of the present invention, disconnection and short-circuit failure of the surrounding portion can be prevented.

FIG. 13 shows an example of a cross section of the intersection of the scanning wiring 503 and the signal wiring 504 in the embodiment of FIG. As described with reference to FIG. 7, the scanning wiring 503 and the signal wiring 504 are orthogonal to each other with the gate insulating film 602 interposed therebetween. However, by applying the transparent conductive film of the present invention to the signal wiring 504, It is possible to prevent disconnection defects.
FIG. 14 shows a cross-sectional configuration example of the terminal portion of the scanning wiring 503 in the embodiment of FIG. 12, and FIG. 15 shows a cross-sectional configuration example of the terminal portion of the signal wiring 504 in the embodiment of FIG. 12, respectively.

In FIG. 14, a protective electrode 801 made of a transparent conductive film is provided with a step portion 1401 of the scanning wiring and a gate.
The step portion 1402 of the insulating film 602 is overcome. Further, in FIG. 15, the signal wiring 504 made of a transparent conductive film is provided with the step portion 150 of the gate insulating film 602.
You will get over 1. In any of the embodiments shown in FIGS. 14 and 15, it is possible to prevent disconnection and short-circuiting defects in the surrounding part involving the transparent conductive film.

In the embodiments of FIGS. 6 to 15, the transparent conductive film of the present invention is applied to an active matrix substrate using a reverse stagger type TFT as a switching element, but the present invention is not limited to this. The present invention is not limited to this, and can be applied to the case where a TFT having a different structure such as a positive staggered TFT is used.

FIG. 16 shows an embodiment of a cross section of one pixel of an active matrix substrate using a positive stagger type TFT as a switching element. In FIG. 16, the glass substrate 1
A light-shielding film 1602 for blocking light irradiation from the back surface is provided on a part of 02 through the interlayer insulating film 1601. The light-shielding film 1602 is made of metal such as Al, Cr, Ta, Ti, Mo formed by, for example, sputtering or vapor deposition,
It is composed of an alloy or a metal silicide film.

A pixel electrode 501 and a source / drain electrode 605 made of the transparent conductive film of the present invention are formed on the interlayer insulating film 1601. Source / drain electrode 605
An electrode layer 1603 doped with impurities such as phosphorus is formed on the upper surface of the substrate to compensate for contact with the channel semiconductor layer 603. An island of an amorphous silicon film 603 which will be a channel semiconductor layer of the TFT 502 is formed on the gate insulating film 602. A gate electrode 601 is formed on a part of this island.

Further, the TFT 502 and the pixel electrode 501
A passivation film 608 is formed so as to cover the entire upper surface. The gate electrode 601 and the source / drain electrode 605 become the scanning wiring 503 and the signal wiring 504, respectively, in the extended portions.

Also in this embodiment, since the shapes 1604 and 1605 of the etching end portions of the pixel electrode 501 have a good etching end shape of the forward taper, the source / drain electrode 605 and the gate insulation are formed. Around the etching end portions of the film 602 and the passivation film 608, a step difference is improved, and disconnection at the end portions and short circuit defects due to dielectric breakdown can be prevented.

FIG. 17 shows a pixel electrode 501 shown in FIG.
And the source / drain electrode 605 and the signal wiring 504 are also used as the transparent conductive film of the present invention. In FIG. 17, reference numeral 1701 denotes a pixel electrode 501 and a source electrode.
This is a pattern in which the drain / electrode 605 is integrated. In this case, the island pattern of the amorphous silicon film 603 to be the channel semiconductor layer directly crosses over the etching end 1702 of the transparent conductive film pattern 1701.

In addition, the transparent conductive film pattern 1701 has the step portion 1 of the light shielding film 1602 with the interlayer insulating film 1601 interposed therebetween.
You will get over 703. Also in this embodiment,
By applying the transparent conductive film of the present invention, it is possible to prevent disconnection and short circuit defects in the surrounding portion.

In the above embodiments, the transparent conductive film pattern itself is attached to the step portion formed of an insulating film, a metal film, an alloy film, a metal silicide film, a semiconductor film, or a laminated film thereof. The improvement effect depends on the shape of the step portion that the transparent conductive film pattern gets over, and the taper
It was confirmed that the taper was effective in the normal taper shape having an angle of 90 degrees or less.

Although the transparent conductive film of the present invention is applied to the active matrix substrate 505 of the color liquid crystal display device shown in FIG. 5 in the above embodiments, the present invention is not limited to this. For example, if the present invention is applied to a liquid crystal display device having a part of an electrode configuration obtained by patterning a transparent conductive film, it is possible to improve the surrounding of a step involving the transparent conductive film. The effect of can be obtained.

[0087]

According to the present invention, by using a polycrystalline indium tin oxide film randomly oriented with respect to a substrate as a transparent conductive film, a film structure in which crystal grains of uniform size are densely packed is formed. can get. Therefore, the inside of the crystal grain and the crystal grain boundary are uniformly etched, and a good etching end shape is obtained. As a result, even when the insulating film, the wiring, and the semiconductor are laminated on the transparent conductive film pattern, the step around the edge of the transparent conductive film pattern is improved, and a liquid crystal display device without a short circuit or a disconnection defect is provided. can get.

Further, the step portions of the insulating film, the wiring, the semiconductor, and the through hole opened in the insulating film are formed on the transparent conductive film pattern.
Even in the case where the transparent conductive film gets over, the surrounding of the transparent conductive film itself at the step portion is improved, so that a liquid crystal display device without the disconnection defect of the transparent conductive film can be obtained.

As described above, according to the present invention, since the wiring around the step portion, which involves the transparent conductive film, is improved, disconnection of wiring and short circuit defects can be reduced, and the yield is improved. A display device is obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a relationship between a film structure of polycrystalline indium tin oxide and a shape of an etching end portion.

FIG. 2 is an explanatory diagram showing the relationship between the crystal grain size and the X-ray diffraction peak intensity ratio of (400) plane to (222) plane of the polycrystalline indium tin oxide film used in the liquid crystal display device according to the present invention. Is.

FIG. 3 is a characteristic diagram showing the relationship between the X-ray diffraction peak intensity ratio of the (400) plane to the (222) plane of the polycrystalline indium tin oxide film used in the liquid crystal display device according to the present invention and the etching rate. is there.

FIG. 4 is a characteristic chart showing the relationship between the X-ray diffraction peak intensity ratio of the (400) plane to the (222) plane of the polycrystalline indium tin oxide film used in the liquid crystal display device according to the present invention and the side etch amount. Is.

FIG. 5 is a perspective view showing a configuration of an example of a color liquid crystal display device using a randomly oriented polycrystalline indium tin oxide film as a transparent conductive film as a part of an active matrix substrate.

FIG. 6 is a sectional view showing a first example of a sectional configuration of one pixel of an active matrix substrate in a liquid crystal display device according to the present invention.

7 is a cross-sectional view showing an example of a cross-sectional configuration of an intersection of a scanning wiring and a signal wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

8 is a cross-sectional view showing a cross-sectional configuration example of a terminal portion of a scanning wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

9 is a cross-sectional view showing a cross-sectional configuration example of a terminal portion of a scanning wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

FIG. 10 is a sectional view showing a second example of the sectional configuration of one pixel of the active matrix substrate in the liquid crystal display device according to the present invention.

FIG. 11 is a sectional view showing a third example of the sectional configuration of one pixel of the active matrix substrate in the liquid crystal display device according to the present invention.

FIG. 12 is a sectional view showing a fourth example of the sectional configuration of one pixel of the active matrix substrate in the liquid crystal display device according to the present invention.

13 is a cross-sectional view showing an example of a cross-sectional configuration of an intersection of a scanning wiring and a signal wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

14 is a cross-sectional view showing a cross-sectional configuration example of a terminal portion of a scanning wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

15 is a cross-sectional view showing a cross-sectional configuration example of a terminal portion of a signal wiring in the active matrix substrate of the liquid crystal display device according to the present invention shown in FIG.

FIG. 16 is a sectional view showing a fifth example of the sectional configuration of one pixel of the active matrix substrate in the liquid crystal display device according to the present invention.

FIG. 17 is a sectional view showing a sixth example of the sectional configuration of one pixel of the active matrix substrate in the liquid crystal display device according to the present invention.

[Explanation of symbols]

 101 Polycrystalline Indium Tin Oxide (ITO) Film 102 Glass Substrate 103 Part Showing Good Etching Edge Shape 104 Abnormal Growth Particles 105 Crystal Grain Boundary 501 Pixel Electrode 502 TFT 503 Scanning Wiring 504 Signal Wiring 505 Active Matrix Substrate 506 Liquid Crystal Layer 507 Counter electrode 508 Color filter 509 Insulating substrate 510 Deflection plate 601 Gate electrode 602 Gate insulating film 603 Amorphous silicon film 604 Amorphous silicon film doped with impurities 605 Source / drain electrode 606 TFT Channel part 607 Opening part 608 Passivation film 801 Terminal part protection electrode 901 Terminal part extraction electrode 1201 Transparent conductive film pattern 1701 Transparent conductive film pattern 1601 Interlayer insulating film 1602 Light shielding film, 1603 Impurity doping Electrode layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Onizawa 7-1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory

Claims (18)

[Claims] 1. An insulating substrate having a transparent conductive film pattern provided on at least a part of a main surface of an insulating substrate, and an insulating substrate having a counter electrode provided on at least a part of the main surface of the insulating substrate. In a liquid crystal display device having a structure in which liquid crystal is sandwiched in a gap obtained by facing the substrates so that their main surfaces are opposed to each other, the transparent conductive film is polycrystalline oxide in which tin oxide is added to indium oxide. A liquid crystal display device, which is an indium tin (ITO) film, in which each crystal grain is a columnar crystal and is randomly oriented. 2. The transparent conductive film has an X-ray diffraction peak intensity ratio of (400) plane to (222) plane of 25 to 75%.
Randomly oriented polycrystalline indium tin oxide in the range
The liquid crystal display device according to claim 1, wherein an (ITO) film is used. 3. The transparent conductive film has a thickness of 30 to 500.
The liquid crystal display device according to claim 1, wherein the liquid crystal display device has a thickness of nm. 4. The step shape of the end portion of the transparent conductive film pattern is a forward taper shape having a taper angle of 45 degrees or less. The liquid crystal display device according to claim 1. 5. The crystal grain size of the transparent conductive film is 17-2.
It is 3 nm, The liquid crystal display device in any one of Claim 1 thru | or 4 characterized by the above-mentioned. 6. The liquid crystal display device according to claim 1, wherein the unevenness on the surface of the transparent conductive film is 30% or less with respect to the film thickness. 7. The amount of tin oxide added to the transparent conductive film is
The amount is 3 to 12% by weight.
The liquid crystal display device according to any one of 1. 8. The method according to claim 1, wherein the transparent conductive film is used as a wiring, a pixel electrode, or a part of a lead terminal for connection with an external driving circuit. Liquid crystal display device. 9. The liquid crystal display device according to claim 1, which has a structure in which an insulating film is laminated on at least a part of the transparent conductive film pattern. 10. A structure in which a metal film, an alloy film, or a metal silicide film is laminated on at least a part of the transparent conductive film pattern directly or with an insulating film interposed therebetween. 9. The liquid crystal display device according to any one of 8. 11. The liquid crystal display device according to claim 1, wherein a structure in which a semiconductor film is laminated on at least a part of the transparent conductive film pattern is used. 12. The liquid crystal display device according to claim 1, having a structure in which the transparent conductive film patterns are laminated so as to get over at least a part of the stepped portion of the insulating film. . 13. A structure in which the transparent conductive film pattern is laminated so as to pass over at least a part of the stepped portion of the metal film, the alloy film, or the metal silicide film directly or via the insulating film. The liquid crystal display device according to any one of claims 1 to 8. 14. The transparent conductive film pattern is laminated so as to cross over at least a part of a step portion of a structure in which a semiconductor film is laminated on a semiconductor film or an insulating film. The liquid crystal display device according to any one of 1. 15. The stepped portion over which the transparent conductive film pattern rides has a shape of a forward taper having a taper angle of 90 degrees or less. The liquid crystal display device according to claim 1. 16. A metal film of Al, Cr, Ta, Ti, Mo, etc., an alloy film, a metal silicide film, or a laminated film thereof is nitrided as the insulating film as the metal film, alloy film, or metal silicide film. A silicon film, a silicon oxide film, an oxide film formed by oxidizing a part of the surface of the metal, or a laminated film thereof is used as the semiconductor film, which is an amorphous silicon film or a polycrystalline silicon film, respectively. 16. The liquid crystal display device according to claim 9, wherein the liquid crystal display device is a liquid crystal display device. 17. The method of manufacturing a liquid crystal display device according to claim 1, wherein the transparent conductive film is patterned by a wet etching method. 18. The ferric chloride / hydrochloric acid solution, a halogen acid such as hydrochloric acid, oxalic acid, or hydroiodic acid, or aqua regia is used as the etchant for the wet etching method. A method for manufacturing a liquid crystal display device according to item 1.