JP3548908B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a thin film transistor (TFT) active matrix type liquid crystal display device used as a display device for image information / character information of an OA device or the like.
[0002]
[Prior art]
An active matrix type liquid crystal display device in which TFTs are formed in a matrix on an insulating substrate such as glass and used as switching elements is expected as a high-quality flat panel display.
[0003]
At present, there are some problems to be solved in the TFT active matrix type display.
[0004]
The first problem is to improve the production yield. In particular, short-circuit failure between the scanning signal wiring and the video signal wiring is the largest cause of the failure, and reduction of this failure has been a problem.
[0005]
The second problem is to reduce the number of manufacturing steps. In particular, there is a strong demand for a reduction in the number of photolithography steps.
[0006]
A third problem is a technique for forming a low-resistance scanning signal wiring that can cope with higher definition and larger screen size.
[0007]
The fourth problem is to ensure reliability. Specifically, it is an issue to secure not only reliability of image quality but also reliability against corrosion of external connection terminals of wiring.
[0008]
Various proposals have conventionally been made for the above problems.
[0009]
Regarding the first problem of improving the production yield, for example, Japanese Patent Application Laid-Open No. 61-133662 discloses that a TFT gate insulating film has a two-layer structure of an anodic oxide film of a gate electrode and a SiN film, and a pin hole of a gate insulating film. Discloses a technique for preventing a short circuit between wirings (first related art).
[0010]
Many proposals have been made on the second problem of reducing the number of photolithography steps. For example, Japanese Patent Application Laid-Open No. 63-9977 discloses a structure in which a scanning wiring has a two-layer structure of a transparent electrode and a metal film, and a pixel electrode is formed by the transparent electrode of the scanning wiring. In this method, since the scanning signal wiring and the pixel electrode can be formed by one patterning, the photolithography process can be reduced (second conventional technique).
[0011]
Japanese Patent Application Laid-Open No. 62-32651 discloses a method of reducing the number of photolithography steps by processing a gate insulating film and a semiconductor film constituting a TFT into the same pattern using one photomask. (Third prior art).
[0012]
To solve the third problem of the formation technology of the low-resistance scanning signal wiring, for example, Japanese Patent Application Laid-Open No. 2-85826 discloses that Al is used as the scanning wiring and Al is used as the scanning wiring. ₂ O ₃ An example in which the film is used as a gate insulating film and an interlayer insulating film is disclosed. When low-resistance Al is used for the scanning wiring, the delay of the scanning signal can be suppressed to a practically acceptable level even if the load on the scanning wiring increases due to higher definition / larger screen (fourth prior art). ).
[0013]
Japanese Patent Application Laid-Open No. 64-35421 discloses that Al and Ta formed on Al are used for a scanning wiring, and an anodic oxide film of Al and Ta is used as a gate insulating film and an interlayer insulating film. And a method of reducing interlayer short-circuit defects and reducing the number of steps (fifth conventional technique).
[0014]
[Problems to be solved by the invention]
In order for TFT active matrix type liquid crystal display devices to become widely used, it is necessary to simultaneously solve all the above-mentioned problems and realize high image quality / low cost / high reliability. However, although the above-mentioned prior art has given a certain effect for each of the aimed problems, each of the elemental technologies often has a trade-off relationship with each other, and it is not possible to satisfy all of the above-mentioned problems at the same time. . Further, simply combining the above-described individual techniques causes a new problem and cannot achieve a desired effect. The situation will be explained.
[0015]
For example, when the first related art and the second related art are combined, it is necessary to anodize the scanning signal wiring metal on the transparent electrode. When a metal is anodized on a transparent conductive film, there is a problem that the metal film is dissolved by a battery reaction due to a difference in standard potential of the material. Further, in order to form a resist mask for selective oxidation at the time of anodic oxidation, a new photomask is required, so that the second problem of reduction in the number of steps cannot be achieved.
[0016]
Further, in the second prior art, since the semiconductor film as the active layer protrudes outside the gate electrode, a backlight or external light hits the semiconductor film protruding outside the gate electrode when a display device is formed. In addition, the leak current of the TFT increases due to the photocurrent of the semiconductor film, and the image quality deteriorates. In order to prevent this deterioration in image quality, it is effective to reduce the thickness of the semiconductor film. However, as is well known, in order to reduce the thickness of a semiconductor film using a conventional inverted staggered TFT due to process restrictions, a photomask for forming a channel protection film for protecting a channel portion of the TFT requires one photomask. I have to add more. This problem is described, for example, in “Flat Panel Display '91” (Nikkei BP 1990), pp. 88-96.
[0017]
Therefore, in the second conventional technique, although the number of photomasks can be reduced by integrating the masks of the semiconductor film and the gate insulating film, it is necessary to reduce the thickness of the semiconductor film in order to guarantee image quality that can be used practically. In order to form the channel protective film, the number of photomasks must be increased by one, and as a result, the process simplification by reducing the number of photomasks cannot be achieved.
[0018]
When the third prior art and the fourth prior art are combined, the scanning signal wiring has a two-layer structure of a transparent electrode and an Al electrode which is a low resistance wiring. In this case, the Al electrode is used as it is for the external connection terminal portion of the scanning signal wiring, or the upper layer of Al is selectively removed, and the transparent electrode is used as the external connection terminal.
[0019]
Since the external connection terminal portion of the wiring is exposed to various solvents and the like even after a post-process such as liquid crystal sealing, there is a problem that when an active metal such as Al is used, it is corroded. Further, when a transparent electrode is used for the terminal portion, when the transparent electrode, which is a metal oxide, and the wiring metal, Al, are oxidized by oxygen in the transparent electrode to form an insulating film at the interface, the contact is formed. There is a problem that the reliability of this is extremely low.
[0020]
In the fifth prior art, there is no contact problem because Ta is formed on Al, but there is a problem that corrosion is likely to occur because Al is also exposed on the side surface of the terminal.
[0021]
Due to the problems described above, when Al is used for the scanning signal wiring, a barrier metal is often inserted between the terminal and the transparent electrode in order to maintain good contact with the transparent electrode. However, a new photomask is required to process the barrier metal. Therefore, reduction of the number of steps, which is the second problem, cannot be achieved.
[0022]
Further, generally, a gate insulating film and a semiconductor film of a TFT are formed at a temperature of about 300 ° C. by a plasma vapor deposition method (PCVD). When Al is used for the scanning signal wiring, many surface irregularities called hillocks grow due to the thermal history in the PCVD process. An electric field concentrates on such irregularities, and extremely lowers the dielectric strength between the scanning signal wiring and the video signal wiring. Therefore, when low-resistance Al is used for the scanning signal wiring, it is difficult to achieve the first problem of improving the manufacturing yield.
[0023]
As described above, the mere combination of the conventional techniques cannot simultaneously solve all of the above-mentioned problems.
[0024]
An object of the present invention is to provide a method for manufacturing a liquid crystal display device using a wiring material that can be manufactured at low cost while securing high reliability and good image quality with a minimum number of photomasks.
[0025]
[Means for Solving the Problems]
The present invention is formed on an insulating substrate to achieve the above object. , And at least partly covered with an insulating film A method for manufacturing a liquid crystal display device having a scanning signal electrode, a video signal electrode formed to intersect the scanning signal electrode, and a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode;
a. A first metal conductive film and Al or an alloy film containing Al as a main component are laminated on the insulating substrate, and the first conductive film and the Al or Al-based alloy film as a main component are substantially Forming the scanning signal electrode by processing into the same pattern
b. Cover a part of the scanning signal electrode Said Step of forming insulating film
c. Removing, from the conductive film constituting the scanning signal electrode, Al or an alloy film containing Al as a main component, using the insulating film as a mask, for a terminal portion of the scanning signal electrode connected to an external drive circuit;
And a method for manufacturing a liquid crystal display device having the same.

[0026]
In the present invention, after the step c,
d. The method may further include forming a transparent conductive film on the first conductive film for the terminal portion.
[0027]
Further, in the step (d), it is preferable that the transparent conductive film is formed on the insulating film continuously from the terminal portion.
[0028]
In the present invention, since a wiring material including an Al film or an alloy film containing Al as a main component is used, generation of hillocks on the Al surface can be suppressed. Therefore, a short circuit between wirings can be reduced when a display device or the like is configured. Such a phenomenon has not been known so far, and has been clarified for the first time by experiments by the inventors.
[0029]
When the multilayer wiring is used for the scanning signal electrode of the liquid crystal display device, the interlayer dielectric strength between the scanning signal electrode and the video signal electrode increases. As a result, it is possible to reduce the short-circuit defect and reduce the resistance of the scanning signal electrode, thereby achieving an increase in the size and definition of the display screen.
[0030]
Further, when the entire surface of Al is covered with an insulating film containing Al as a base material, Al is not exposed to chemicals and the like, so that corrosion resistance can be ensured and hillock generation on the Al surface is further suppressed. it can.
[0031]
When the external connection terminal is constituted by one metal and a transparent conductive film made of a metal oxide formed thereon, the chemical resistance of the terminal is improved, and the insulating barrier layer formed by the reaction between the transparent conductive film and the metal forms an interface. Is difficult to form. Therefore, an increase in the contact resistance of the connection terminal can be prevented, and a highly reliable connection terminal can be obtained.
[0032]
Such a structure can be formed by etching and removing Al using the insulating film formed on the Al surface as a mask. Therefore, the above-described structure can be formed with only one photomask, and at the same time, the effects of reducing the number of steps, securing corrosion resistance, reducing short-circuit defects, and reducing the resistance of the scanning signal electrode can be obtained.
[0033]
A pixel electrode made of a transparent conductive film is arranged below the semiconductor film and the gate insulating film, and the semiconductor film and the gate insulating film are extended along the video signal electrode as a pattern wider than the video signal electrode, and the pixel electrode pattern , The pixel electrode and the video signal electrode can be separated. In this way, even if the distance between the pixel electrode and the video signal electrode is reduced while preventing the short circuit between the pixel electrode and the video signal electrode, pixel defects due to the short circuit can be reduced. Further, the width of the pixel electrode is increased, and the pixel aperture ratio is improved. Therefore, in addition to features such as a reduction in the number of steps, a high yield, low resistance wiring, and an improvement in the reliability of the terminal portion, a liquid crystal display device with low defects and high luminance can be realized.
[0034]
The inventors have found that, after forming a Ta film, if an Al film is continuously formed in a vacuum while keeping the surface cleanliness in particular, the (111) orientation becomes weak and the (220) plane grows preferentially. At the same time, they found that the hillocks on the film surface became smaller. The production method of the present invention is based on this finding. That is, in the manufacturing method of the liquid crystal display device of the present invention, Al growing on the Ta surface is not affected by the adsorption layer and is directly affected by the underlying Ta film, and thus does not occur under normal conditions (220). Priority growth of the surface is realized. When the (220) plane grows preferentially, the orientation changes randomly as a whole, and the hillocks on the film surface decrease.
[0035]
Features and / or effects of other modifications of the present invention will become apparent from the following description of embodiments.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
FIG. 1 is a perspective view of one embodiment of a method for manufacturing a liquid crystal display device according to the present invention. The laminated wiring material of the present embodiment is formed by sequentially laminating a Ta film 10 and an Al film 11 on the glass substrate 1 by magnetron sputtering and processing the same pattern.
[0037]
The upper Al film 11 has a crystal orientation oriented to the (220) plane under the influence of the underlayer. It is conventionally known that when Al, which is a face-centered cubic lattice (fcc), is grown on (110) of Ta having a body-centered cubic lattice (bcc), it is oriented to (111). In the experiment by the inventors, after the Ta film 10 was formed, if the Al film 11 was continuously formed in vacuum while keeping the surface cleanliness in particular, the (111) orientation was weakened and the (220) The surface was found to grow preferentially. At the same time, it was discovered that the hillocks on the membrane surface were reduced.
[0038]
FIG. 2 is a diagram showing a comparison of the surface irregularities of the Al film 11 formed on the glass substrate 1 and the Ta film 10 respectively. The Al film 11 formed on the glass substrate 1 has some hillocks with a height of about 100 nm, whereas the Al film 11 formed on the Ta film 10 has many fine irregularities. There are no big hillocks. This difference is probably due to the fact that Al grows under the influence of a Ta base having fine crystal grains, and as a result, the crystal grains do not grow large, so that the internal stress of the film is alleviated. It is presumed that many minute hillocks are generated.
[0039]
In growing the (220) plane, care must be taken during film formation. It was experimentally confirmed that the (220) orientation did not appear unless Ta and Al were grown continuously without leaving any time while maintaining the cleanliness of the Ta surface. After forming the Ta film, once the discharge is stopped and left for several minutes or more, even if the vacuum is not released, H ₂ An adsorption layer of O or the like is formed, and preferential growth of the (220) plane does not occur. The inventors obtained (220) orientation for the first time by a method in which Ta and Al were slowly moved in a chamber during sputtering. In such a method, Ta and Al are continuously formed while being slightly mixed near the interface. ₂ An adsorption layer such as O is not formed. In other words, Al growing on the Ta surface is not affected by the adsorbed layer and is directly affected by the underlying Ta film, so that preferential growth of the (220) plane, which does not occur under normal conditions, is realized.
[0040]
FIG. 3 is a diagram showing a comparison between the X-ray diffraction pattern of the Al thin film used for the wiring of the present invention and the X-ray diffraction pattern of the conventional Al film. The height of the peak of the diffraction pattern is proportional to the volume of the crystal grain oriented so that the plane indicated at the position of each peak is parallel to the film surface. The intensity ratio between the (220) diffraction peak and the (111) diffraction peak was 0.15 in the conventional Al film, but increased to 0.7 or more in the Al film of the present invention. It can be seen that the diffraction peak from the (220) plane is larger and the diffraction peak from the (111) plane is smaller in the Al film of the present invention than in the conventional Al film. It is considered that crystal grains strongly oriented in the (111) plane in the conventional Al film are changed to random orientation as a whole by the growth of the (220) plane in the Al film of the present invention. That is, the ratio of the intensity of the surface having the largest diffraction peak intensity to the intensity of the surface having the second highest intensity is, for example, about 0.5 in the conventional Al film, but is about 0.5 in the present invention. From 7 to 1.0. For this reason, it is assumed that the average crystal grain size became slightly smaller, the variation in the grain size became smaller, and the grain size became uniform.
[0041]
Conventionally, in an Al wiring used in an LSI, since the resistance to electromigration and stress migration is reduced when Al crystal grains are miniaturized, Al is preferentially oriented to (111) to increase the crystal grains. In such an Al film, a large hillock grows because the number of triple points of crystal grains serving as sites for relaxing stress is small. In a TFT array for a liquid crystal display device, the wiring width is about 10 μm, which is larger than that of an LSI, so that electromigration and stress migration do not pose a significant problem. Rather, it is important to suppress hillocks on the Al surface to suppress interlayer short circuits. Therefore, the suppression of hillocks due to the (220) orientation and the miniaturization of crystal grains of the present invention is very desirable as a wiring for a TFT array.
[0042]
FIG. 4 is a diagram showing the relationship between the intensity ratio of the (220) diffraction peak and the (200) diffraction peak obtained from the X-ray diffraction of the Al film and the surface hillock density. It can be seen that the hillock density decreases as the (220) / (200) ratio increases, and that the hillocks almost disappear when the (220) / (200) ratio exceeds 1.0.
[0043]
As a material of the base, not only Ta but also a metal having a crystal structure of bcc may be used. For example, Ta-N alloy, Nb, Ta-Nb alloy, Nb-N alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta-W-N Similar effects can be obtained with alloys. The material of the upper layer is not limited to pure Al, but may be an Al alloy film such as Al-Pd, Al-Ta, Al-Ta-Ti, or the like.
[0044]
The Al film of the present invention can be grown on the above alloy containing Ta whose surface is clean. In addition to the method of continuously forming a film after the formation of the base film, the formed base surface is sputter-etched. Then, a method of performing film formation after cleaning with the above method can also be adopted.
[0045]
Embodiment 2
FIG. 5 is a plan view of a scanning signal wiring for a liquid crystal display device constituted by using the above-mentioned laminated wiring material of the present invention. FIG. 6 is a sectional view of an external connection terminal portion of the scanning signal wiring of FIG. FIG. 7 is a cross-sectional view of the AA plane of FIG. 6 viewed from the direction of the arrow.
[0046]
A Ta electrode 10 and an Al electrode 11 are formed on a glass substrate 1, and their surfaces and side surfaces are made of Ta. ₂ O ₅ Film 20 and Al ₂ O ₃ It is covered by the membrane 21. Here, Al ₂ O ₃ The film 21 was formed so as to cover the entire surface of the Al electrode 11 which is the upper layer film of the two-layer conductive film. Further, the Al electrode 11, which is an upper layer film, is formed from a position at a distance X or more from the end of the scanning signal electrode (the distance X is 1.0 cm in this example), and is formed from the end in contact with the external member. The Al electrode 11 was eliminated.
[0047]
According to the present embodiment, the easily corroded Al electrode is completely ₂ O ₃ Since a low-resistance Al electrode can be used for the scanning signal electrode while being covered with the film and being excluded from the end portion in contact with the external member, high definition and large size of the display device can be achieved. In order to reliably connect to the external member, X may be set to 0.1 cm or more. In addition, a highly corrosion-resistant Ta is arranged under the easily corroded Al electrode, ₂ O ₃ The structure is such that the end faces of the film and the Al electrode coincide with each other. ₂ O ₃ Since the external connection terminal is formed by etching away the Al electrode at the end using the film as a mask, a photomask for metal-working the connection terminal is not required, and the number of steps can be reduced. Furthermore, since the (220) -oriented Al electrode having few hillocks is used as the upper layer film, interlayer short-circuit failure can be reduced. Thus, high quality Al ₂ O ₃ Since the film can be used as an interlayer insulating film, interlayer short-circuit defects can be further reduced.
[0048]
Embodiment 3
FIG. 8 is a sectional view showing an end of another embodiment of the scanning signal electrode of the liquid crystal display device according to the present invention. FIG. 9 is a cross-sectional view of the AA plane of FIG. 8 as viewed from the direction of the arrow.
[0049]
The scanning signal electrode of the present embodiment is composed of a three-layered conductive film including a two-layered Ta electrode 10 and an Al electrode 11 sandwiched therebetween. As in the above embodiment, the surfaces and side surfaces of these films are made of Ta. ₂ O ₅ Film 20 and Al ₂ O ₃ The surface of the Ta electrode 10 which is covered with the film 21 and which is the uppermost film is entirely formed of Ta. ₂ O ₅ Coated with membrane 20. In addition, the Ta electrode 10 and the Al electrode 11 of the upper layer were formed at a distance of 1.0 cm or more from the end of the scanning signal electrode, and the Al electrode 11 was excluded from the end in contact with the external member.
[0050]
According to the present embodiment, in addition to the effect similar to that of the first embodiment, Ta having a large relative dielectric constant is used. ₂ O ₅ Since the film can be used as a part of the gate insulating film of the TFT, the mutual conductance of the TFT is improved. Further, the generation of hillocks in the Al electrode 11 can be further suppressed by the Ta electrode 10 in the upper layer, and interlayer short-circuit failure can be reduced.
[0051]
Embodiment 4
FIG. 10 is a schematic cross-sectional view of a unit pixel of a liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment.
[0052]
A scanning signal electrode composed of a Ta electrode 10 and an Al electrode 11 is formed on a glass substrate 1, and the surface and side surfaces thereof are made of Ta. ₂ O ₅ Film 20 and Al ₂ O ₃ It is covered with the film 21. On these scanning signal electrodes, a SiN film 22, an a-Si: H film 30, and an n-type a-Si: H film 31 are formed. On the n-type a-Si: H film 31, a video signal electrode 14 and A source electrode 15 is formed, and the pixel electrode 13 made of an ITO film is connected to the source electrode. A capacitance electrode 16 is connected to the pixel electrode 13, and the scanning signal electrode 11 and the capacitance electrode 16 form an additional capacitance. Further, the whole is covered with a protective SiN film 23.
[0053]
FIG. 11 is a cross-sectional view of the external connection terminal of the scanning signal electrode of the thin film transistor substrate. Here, of the scanning signal electrodes, the surface of the upper Al electrode 11 is made of Al. ₂ O ₃ The Ta electrode 10 is covered with a film 21 ₂ O ₃ It extends outside the film 21 to constitute an external connection terminal. The Ta electrode 10 is covered with an ITO electrode 13. In the present embodiment, since the insulation of the barrier layer formed at the Ta / ITO interface due to the reaction between Ta and ITO is not perfect, the contact resistance between Ta and ITO is lower than that in the case where Al and ITO are combined, for example. , Is much smaller. In addition, in the case of Ta and ITO, since the contact resistance hardly increases due to the heat treatment, extremely stable connection terminals can be obtained.
[0054]
In this embodiment, Ta is used as the base metal, but in addition to Ta, Ta-N alloy, Nb, Ta-Nb alloy, Nb-N alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti alloy are also used. A similar effect can be obtained with an -N alloy, W, a Ta-W alloy, a Ta-W-N alloy, or the like. In particular, when a metal nitride such as Ta-N or Ti-N is used, the reaction between the metal and ITO can be further suppressed, and the contact resistance can be extremely reduced.
[0055]
12 to 16 are views showing the steps of manufacturing the thin-film semiconductor device of the embodiment. The right side of these figures is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
[0056]
In FIG. 12, a Ta film 10 and an Al film 11 are continuously deposited on a glass substrate 1 by sputtering, and are patterned into a predetermined shape by using a photolithography technique.
[0057]
In FIG. 13, the surface and side surfaces of the Ta film 10 and the Al film 11 are anodized to form Ta. ₂ O ₅ Film 20 and Al ₂ O ₃ A film 21 is formed.
[0058]
In FIG. 14, Al ₂ O ₃ Using the film 21 as a mask, the Al film 11 in the scanning signal electrode terminal portion is removed by etching to expose the Ta electrode 10. At this time, hydrogen bromide (HBr) and boron trichloride (BCl ₃ According to the reactive ion etching method using the mixed gas plasma of (1) and (2), the etching selectivity between Al and Ta can be increased, so that the working margin of the etching is increased and the yield is improved. Subsequently, an ITO film is deposited by sputtering, and is patterned using photolithography to form the pixel electrode 13 and the protective film 131 of the terminal Ta.
[0059]
In FIG. 15, a gate SiN film 22, an a-Si: H film 30, and an n-type a-Si: H film 31 are deposited by a plasma CVD method, and an a-Si: H film 30, an n-type a-Si: The H film 31 is patterned into a predetermined shape, and then the gate SiN film 22 on the pixel electrode 13 and the terminal electrode is removed.
[0060]
In FIG. 16, a Ti film is deposited by sputtering and patterned into a predetermined shape to obtain a video signal electrode 14, a source electrode 15, and a capacitor electrode 16. Finally, the protective SiN film 23 is formed by the plasma CVD method, and the thin film semiconductor device is completed.
[0061]
According to this embodiment, Ta having high corrosion resistance can be used for the external connection terminal, so that high reliability can be ensured. Also, Al ₂ O ₃ Since the Ta electrode of the external connection terminal portion is exposed using the film as a mask, a photomask for processing the external connection terminal metal, which is conventionally required, becomes unnecessary, and the number of steps can be reduced. Furthermore, by suppressing hillocks on the Al surface, interlayer short-circuits can be reduced, and a low-resistance Al electrode can be used as the scanning signal electrode, so that a higher definition and larger size of the liquid crystal display device can be realized.
[0062]
In the above embodiments, Ta and Al were used for the scanning signal electrodes. However, the present invention is not limited to this combination, and instead of Ta, W, Nb or an alloy containing these components, for example, TaN, Nb-N, Ta -Nb-N, Ta-Ti-N or the like can be similarly used. Further, not limited to pure Al, an alloy such as Al-Pd, Al-Ta, or Al-Ti-Ta may be used.
[0063]
Furthermore, in the above embodiment, the Al formed on the surface of Al ₂ O ₃ Although the method of exposing the Ta electrode of the external connection terminal using the film as a mask is employed, the step of exposing the Ta electrode of the external connection terminal may be performed after removing the gate SiN film 22 on the terminal electrode. Also in this case, the photoresist for processing the gate SiN film 22 can be used as it is as a mask for exposing the Ta electrode 10, so that the number of steps does not increase.
[0064]
The gate SiN film or Al is applied to the plasma when the Ta electrode is exposed. ₂ O ₃ Since the film is not directly exposed and plasma damage does not occur in the film, good insulating properties can be maintained.
[0065]
Embodiment 5
The wiring material according to the present invention can be applied to not only the scanning signal wiring but also the video signal wiring. FIG. 17 is a sectional view of a pixel according to an embodiment in which the wiring material according to the present invention is applied to a video signal wiring. In the present embodiment, in addition to the structure of the first embodiment, the video signal wiring, the source electrode, and the capacitor electrode are formed of a stacked electrode of Ta films 141, 151, 161 and Al films 142, 152, 162. By adopting such a structure, the Al films 142, 152, and 162 have the (220) orientation. For the reason described above, the growth of whiskers and hillocks from the Al film by the heat treatment at the time of forming the protective film 23 is prevented. Can be prevented.
[0066]
Embodiment 6
FIG. 18 is a sectional view of a pixel portion of another embodiment of the liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment shown in FIG. FIG. 19 is a plan view of the embodiment of FIG.
[0067]
As in the embodiment, a scanning signal electrode including a Ta electrode 10 and an Al electrode 11 is formed on a glass substrate 1. The surface and sides of these electrodes are Ta ₂ O ₅ Film 20 and Al ₂ O ₃ It is covered with the film 21. On these scanning signal electrodes, a 400-nm-thick SiN film 22 and a 50-nm-thick a-Si: H film 30 are formed in the same plane shape. And a source electrode 15 are formed. The pixel electrode 13 made of an ITO film is connected to the source electrode 15.
[0068]
The pixel electrode 13 is arranged below the SiN film 22, and the a-Si: H film 30 and the SiN film 22 extend along the video signal electrode 14 below the video signal electrode 14, : H film 30 and SiN film 22 cover only the periphery of the pattern of pixel electrode 13. A capacitance electrode 16 is connected to the pixel electrode 13, and the scanning signal electrode 11 and the capacitance electrode 16 form an additional capacitance. These are all covered with a protective SiN film 23.
[0069]
FIG. 20 is a sectional view of the a-Si: H film 30 taken along the line AA in FIG. ³¹ P and ¹¹ FIG. 7 is a diagram illustrating a density distribution of B in a depth direction. FIG. 21 is a cross-sectional view of the a-Si: H film 30 taken along the line BB in FIG. ³¹ P and ¹¹ FIG. 7 is a diagram illustrating a density distribution of B in a depth direction.
[0070]
In the BB section in contact with the source electrode 15, ³¹ Only P decreases exponentially from the surface Steep Introduced in concentration profiles. In the AA cross section, which is the channel region of the TFT, almost the same amount ³¹ P and ¹¹ B has been introduced.
[0071]
With the above configuration, the present embodiment has the following effects in addition to the effects described above.
[0072]
a. Since the a-Si: H film 30 and the gate SiN film 31 which have been conventionally patterned by separate photomasks are patterned into the same shape by one photomask, the number of photolithography steps is reduced by one, and the number of steps is reduced. It is possible to reduce the production cost.
[0073]
b. The channel region of the TFT is ³¹ P and ¹¹ Since B is compensated for each other and the resistance is increased, the source electrode and the drain electrode can be separated without etching the n-type a-Si: H film, which is conventionally required. Can be made thinner. When the thickness of the a-Si: H film 30 is 60 nm or less, a decrease in the off-resistance of the TFT due to a photocurrent can be prevented, and good image quality can be obtained. In addition, when the a-Si: H film 30 is thinned, the formation of a channel protective film, which is conventionally required, is not required, and the number of manufacturing steps is not increased.
[0074]
c. Since the pixel electrode 13 and the video signal electrode 14 are separated by the a-Si: H film 30 and the gate SiN film 22, the pixel electrode 13 and the video signal electrode 14 are not short-circuited. Therefore, it is possible to reduce pixel defects mainly caused by short-circuit between the pixel electrode 13 and the video signal electrode 14. Further, the distance between the pixel electrode 13 and the video signal electrode 14 can be reduced, and the area of the pixel electrode 13 can be increased accordingly, and the pixel aperture ratio can be improved. As a result, high brightness of the display can be achieved.
[0075]
22 to 29 are cross-sectional views showing the manufacturing steps of the embodiment shown in FIG.
[0076]
In FIG. 22, a Ta film 10 and an Al film 11 are deposited on a glass substrate 1 by sputtering, and are patterned into a predetermined shape using a photolithography technique. Next, Ta is applied to the surface and side surfaces of the Ta film and the Al film by anodic oxidation. ₂ O ₅ Film 20 and Al ₂ O ₃ A film 21 is formed.
[0077]
In FIG. 23, an ITO film is deposited to a thickness of 110 nm by sputtering and patterned to form a pixel electrode 13.
[0078]
In FIG. 24, a gate SiN film 22 is deposited to a thickness of 400 nm by plasma CVD, and an a-Si: H film 30 is formed to a thickness of 50 nm.
[0079]
In FIG. 25, PH ₃ PH +, PH without mass separation extracted from gas discharge plasma ₂ Irradiation with ions such as + at a low energy of about 2 keV introduces P into the a-Si: H film 30. As an impurity doping technique using an ion beam without mass separation, for example, a method using a magnetic bucket type ion source is disclosed in Japanese Patent Application Laid-Open No. 2-199824.
[0080]
In FIG. 26, the gate SiN film 22 and the a-Si: H film 30 are processed into the same planar shape by photolithography.
[0081]
In FIG. 27, a Ti electrode is formed by sputtering and patterned to obtain a video signal electrode 14, a source electrode 15, and a capacitor electrode 16.
[0082]
In FIG. 28, the patterns of the video signal electrode 14 and the source electrode 15 are used as a mask, and BH +, B ₂ H ₂ Irradiation of ions such as + at a low energy of about 2 keV introduces B into the channel region of the a-Si: H film 30. This is because the discharge gas is B ₂ H ₆ If a gas containing B is used, it can be easily realized.
[0083]
In FIG. 29, a protective SiN film is formed to complete the device.
[0084]
By adopting the above-described manufacturing process, as described above, the formation of the channel protective film, which was conventionally required when the a-Si: H film 30 is thinned, becomes unnecessary, so that the manufacturing process can be simplified. In particular, when a low-energy ion beam without mass separation is used as an impurity introduction method, impurities can be efficiently introduced into a large area, so that production efficiency is improved.
[0085]
FIG. 30 is an equivalent circuit of a TFT substrate in the liquid crystal display device of the present invention. On a glass substrate 1, a plurality of scanning signal electrodes 10/11, a plurality of video signal electrodes 14 orthogonal thereto, TFTs connected to these electrodes, and a liquid crystal capacitor and an additional capacitor connected to the TFTs. It is formed. A terminal 140 for connecting an external member is provided at one end of the scanning signal electrode 10/11 and the video signal electrode 14.
[0086]
To display an image, a pulse signal is sequentially applied to the scanning signal electrodes 10/11 to turn on one row of TFTs, and during that time, an image signal is applied from the video signal electrode to the liquid crystal layer. This operation is repeated for each row.
[0087]
FIG. 31 is an equivalent circuit of another TFT substrate in the liquid crystal display device of the present invention. It is composed of a plurality of scanning signal electrodes 10 and 11 on a glass substrate 1, a plurality of video signal electrodes 14 orthogonal thereto, TFTs connected to these electrodes, and a liquid crystal capacitance and an additional capacitance connected to the TFTs. However, in this embodiment, the scanning signal circuit 200 and the video signal circuit 210 for driving the TFT are formed on the glass substrate 1 using the TFT. As described above, since the driving circuit is also integrated on the glass substrate 1, the number of external components is significantly reduced, so that the overall cost can be significantly reduced. Needless to say, the wiring material of the present invention can be similarly applied even when such external connection terminals are small.
[0088]
In the embodiment described above, an example using an inverted staggered thin film transistor is described. However, the wiring material of the present invention is not limited to this, and is similarly applied to a thin film transistor having a staggered or coplanar electrode structure. It is possible and the same effect can be obtained.
[0089]
FIG. 32 is a diagram showing a schematic cross section of a liquid crystal display device constituted by the thin film semiconductor device according to the present invention. 32 shows the cross section of one pixel portion, the left side shows the cross section of the left edge portion of the pair of glass substrates 1 and 508 where the external lead-out terminal exists, and the right side shows the cross section of the pair of glass substrates 1. And 508 show a cross section of the right edge of the portion where no external lead-out terminal exists.
[0090]
On the lower glass substrate 1 with reference to the liquid crystal layer 506, the scanning signal electrodes 11 and the video signal electrodes 14 are formed in a matrix. The TFT formed near the intersection drives the pixel electrode 13 made of ITO. A counter electrode 510 made of ITO, a color filter 507, a color filter protective film 511, and a light-shielding film 512 serving as a light-shielding black matrix pattern are formed on an opposite glass substrate 508 facing the liquid crystal layer 506 therebetween. The sealing material SL shown on each of the left and right sides of FIG. 32 is formed along the entire edge of the glass substrates 1 and 508 except for a liquid crystal sealing port (not shown) so as to seal the liquid crystal layer 506. I have. The sealing material is, for example, an epoxy resin.
[0091]
The opposing electrode 510 on the opposing glass substrate 508 is connected to an external lead wire formed on the glass substrate 1 by a silver paste material SIL at at least one place. The external connection wiring is formed in the same manufacturing process as each of the scanning signal wiring 10, the source electrode 15, and the video signal electrode 14. Each layer of the alignment films ORI1, ORI2, the pixel electrode 13, the protective film 23, the color filter protective film 511, and the gate SiN film 21 is formed inside the sealing material SL. The polarizing plate 505 is formed on the outer surfaces of the pair of glass substrates 1 and 508, respectively.
[0092]
The liquid crystal layer 506 is sealed between the lower alignment film ORI1 and the upper alignment film ORI2 for setting the direction of the liquid crystal molecules, and is sealed by the sealing material SL. The lower alignment film ORI1 is formed above the protective film 23 on the glass substrate 1 side. On the inner surface of the opposing glass substrate 508, a light-shielding film 512, a color filter 507, a color filter protective film 511, an opposing electrode 510, and an upper alignment film ORI2 are sequentially laminated.
[0093]
This liquid crystal display device is assembled by separately forming a layer on the glass substrate 1 side and a layer on the opposing glass substrate 508 side, and then superimposing the upper and lower glass substrates 1 and 508, and sealing the liquid crystal 506 therebetween. When the transmission of light from the backlight BL is adjusted at the pixel electrode 13, a TFT-driven color liquid crystal display device is formed.
[0094]
Since the liquid crystal display device of the present invention can use the scanning signal electrode made of low-resistance Al, it is suitable for enlargement and high definition. In addition, since the manufacturing can be performed with a simple manufacturing process with a high yield, the cost can be significantly reduced and an inexpensive liquid crystal display device can be provided.
[0095]
The characteristic configuration of the present invention is exemplified as follows.
[0096]
1. An Al film in which the volume ratio between crystal grains oriented so that the (220) plane is parallel to the film surface and crystal grains oriented so that the (200) plane is parallel to the film surface is 0.5 or more; A wiring material including an alloy film containing Al as a main component.
[0097]
2. An Al film in which the volume ratio between crystal grains oriented so that the (220) plane is parallel to the film surface and crystal grains oriented so that the (111) plane is parallel to the film surface is 0.5 or more; A wiring material including an alloy film containing Al as a main component.
[0098]
3. A wiring material in which the ratio of the volume of the crystal grains having the second orientation direction having the second largest content to the volume of the crystal grains having the first orientation direction having the largest content is substantially 0.5 or more.
[0099]
4. Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta-W-N Stacked wiring composed of a first conductive film made of one of the alloys and a second conductive film made of Al or an alloy containing Al as a main component and formed on the first conductive film material.
[0100]
5. In the multilayer wiring material according to the above 4, the crystal grains oriented so that the (220) plane included in the Al film or the alloy film containing Al as a main component is parallel to the film surface and the (200) plane are the film surface A multilayer wiring material having a volume ratio of 0.5 or more to crystal grains oriented so as to be parallel to the multilayer wiring material.
[0101]
6. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, at least one of a scanning signal electrode and a video signal electrode is formed by crystal grains having a (220) plane oriented parallel to a film surface. A liquid crystal display device formed of a wiring material including an Al film or an alloy film containing Al as a main component, the volume ratio of which is 0.5 or more to crystal grains oriented so that the plane is parallel to the film surface.
[0102]
7. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor, at least one of a scanning signal electrode and a video signal electrode is composed of Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb alloy. A first conductive film made of one of Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, and Ta-W-N alloy; A liquid crystal display device formed of a stacked wiring material including an alloy as a component and a second conductive film formed over a first conductive film.
[0103]
8. 7. In the liquid crystal display device described in the above item 7, crystal grains oriented so that the (220) plane included in Al or an alloy containing Al as a main component is parallel to the film surface and the (200) plane is parallel to the film surface. A liquid crystal display device in which the volume ratio with the crystal grains oriented as follows is 0.5 or more.
[0104]
9. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device including a pixel electrode and driving liquid crystal by a thin film transistor, the scanning signal electrode is a laminated film of two or more conductive films including at least an Al film or an alloy film containing Al as a main component. Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta-W-N alloy A liquid crystal display device in which a conductive film made of one of these metals is arranged above and below an Al film or an alloy film containing Al as a main component.
[0105]
10. 10. The liquid crystal display device according to any one of the above items 6 to 9, wherein a coating insulating film containing Al as a base material is formed on the surface and side surfaces of the Al film or an alloy film containing Al as a main component.
[0106]
11. 10. The liquid crystal display device according to any one of the above items 6 to 9, wherein the Al film or the alloy film containing Al as a main component is present only at a position separated by 0.1 cm or more from one end of the scanning signal electrode.
[0107]
12. 12. The liquid crystal display device according to any one of the items 6 to 11, wherein a film forming at least one of the scanning signal electrode and the video signal electrode is a gate electrode of a thin film transistor.
[0108]
13. 13. The liquid crystal display device according to any one of the items 6 to 12, wherein the insulating film containing Al as a base material is an Al oxide film or a nitride film.
[0109]
14． A scanning signal electrode formed on an insulating substrate, a video signal electrode formed to cross the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a pixel connected to the thin film transistor In a liquid crystal display device having an active matrix substrate composed of electrodes and an external driving circuit connected to the active matrix substrate and driving liquid crystal by a thin film transistor, a connection terminal between the external driving circuit and a video signal electrode or a scanning signal electrode Are Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta-W A first conductive film made of one metal of the -N alloy and a transparent conductive film made of a metal oxide formed on the first conductive film. A liquid crystal display device.
[0110]
15. 6. A scanning signal electrode comprising the wiring according to any one of the above 1 to 5, a gate insulating film of a thin film transistor formed on the scanning signal electrode, a semiconductor film formed on the gate insulating film, and an intersection with the scanning signal electrode. In a liquid crystal display device including a video signal electrode formed so as to form a pixel electrode connected to a thin film transistor, and driving a liquid crystal by the thin film transistor, a semiconductor film and a gate insulating film in contact with the semiconductor film are in the same plane. A liquid crystal display device having a shape.
[0111]
16. 16. The liquid crystal display device according to the item 15, wherein the semiconductor film and the gate insulating film in contact with the semiconductor film extend below the video signal electrode in a pattern wider than the video signal electrode.
[0112]
17． 17. In the liquid crystal display device according to the above 15 or 16, only one of n-type or p-type impurities is introduced into a region of the semiconductor film which is in contact with the source and drain metal electrodes, and into the channel portion. A liquid crystal display device into which both n-type and p-type impurities are introduced.
[0113]
18. 18. In the liquid crystal display device according to any one of the items 15 to 17, the semiconductor film is made of any of hydrogenated amorphous Si, hydrogenated amorphous SiGe, and hydrogenated amorphous Ge having a thickness of 60 nm or less. Liquid crystal display.
[0114]
19. 19. In the liquid crystal display device described in the above item 18, the concentration of the n-type and p-type impurities is 10% at the surface of the semiconductor film. ²¹ cm ^-3 That is, 10 at the interface between the semiconductor film and the gate insulating film. ¹⁹ cm ^-3 A liquid crystal display device as follows.
[0115]
20. 20. The liquid crystal display device according to any one of the items 15 to 19, wherein the pixel electrode is arranged below the semiconductor film and the gate insulating film.
[0116]
21. 21. The liquid crystal display device according to the item 20, wherein the semiconductor film and the gate insulating film cover only the outer peripheral portion of the pixel electrode pattern.
[0117]
22. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a method of manufacturing a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor,
a. Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta A first conductive film made of one of the -W-N alloys and Al or an alloy film containing Al as a main component are successively laminated in vacuum, processed into a predetermined pattern, and scanned. Forming at least one of an electrode and a video signal electrode
b. Forming an insulating film covering a part of the scanning signal electrode;
c. A step of removing only Al or an alloy film containing Al as a main component of the conductive film forming the scanning signal electrode using the insulating film as a mask;
A method for manufacturing a liquid crystal display device including:
[0118]
23. 23. The method for manufacturing a liquid crystal display device according to the above item 22, wherein the insulating film is formed by any one of an anodic oxidation method, a plasma oxidation method, and a plasma nitridation method.
[0119]
24. 23. The method for manufacturing a liquid crystal display device according to the above item 22, wherein the insulating film is formed by a plasma CVD method or a sputtering method.
[0120]
25. 22. In the method for manufacturing a liquid crystal display device according to the above item 22, the step of removing only Al or an alloy film containing Al as a main component among the conductive films forming the scanning signal electrodes using the insulating film as a mask may be performed using a hydrogen halide gas. A method for manufacturing a liquid crystal display device, which is an ion etching method using a mixed gas containing the same.
[0121]
26. 23. The method for manufacturing a liquid crystal display device according to the above item 22, wherein the first conductive film and Al or an alloy film containing Al as a main component are continuously formed while maintaining a vacuum.
[0122]
27. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a method of manufacturing a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor,
a. Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta Forming a first conductive film made of one of the -W-N alloys, and forming an Al film or an alloy film containing Al as a main component thereon while keeping the surface of the first conductive film clean; Forming a scanning signal electrode or a video signal electrode by laminating and processing into a predetermined pattern
b. Forming an insulating film covering a part of the scanning signal electrode or the video signal electrode c. A step of removing only Al or an alloy film containing Al as a main component among conductive films constituting a scanning signal electrode or a video signal electrode using an insulating film as a mask;
A method for manufacturing a liquid crystal display device including:
[0123]
28. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a method of manufacturing a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor,
a. Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta Forming a first conductive film made of one metal of a WN alloy
b. Step of removing a part of the surface layer of the first conductive film
c. Laminating Al or an alloy film containing Al as a main component on the first conductive film from which a part of the surface layer has been removed
d. Forming a scanning signal electrode or a video signal electrode by processing the laminated film into a predetermined pattern
e. Forming an insulating film covering a part of the scanning signal electrode or the video signal electrode;
f. A step of removing only Al or an alloy film containing Al as a main component among conductive films constituting a scanning signal electrode or a video signal electrode using an insulating film as a mask;
A method for manufacturing a liquid crystal display device including:
[0124]
29. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a method of manufacturing a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor,
a. Forming a first conductive film and Al or an alloy film containing Al as a main component on an insulating substrate in a vacuum in succession, and forming a scanning signal electrode by processing into a predetermined pattern;
b. Forming an insulating film based on a material constituting each conductive film on a part of a surface and a side surface of the scanning signal electrode;
c. A step of removing only Al or an alloy film containing Al as a main component of the conductive film forming the scanning signal electrode using the insulating film as a mask;
d. Forming a pixel electrode by forming a transparent electrode film on the entire surface of the substrate and processing it into a predetermined shape
e. Process of forming gate insulating film and semiconductor film on the whole substrate
f. Irradiating the semiconductor film with an ion beam containing phosphorus at an energy of 5 keV or less to introduce phosphorus into the semiconductor film;
g. Process of processing gate insulating film and semiconductor film into the same pattern
h. A step of depositing a conductive film and processing it into a predetermined pattern to form a video signal electrode and a source electrode
i. A step of irradiating the semiconductor film with an ion beam containing boron at an energy of 5 keV or less using the pattern of the video signal electrode and the source electrode as a mask to introduce boron into the semiconductor film;
A method for manufacturing a liquid crystal display device including:
[0125]
30. 22. An information processing apparatus comprising the liquid crystal display device according to any one of the above items 6 to 21 as display means.
[0126]
31. A liquid crystal produced by the production method according to any one of the above items 22 to 29 display An information processing device comprising the device as a display means.
[0127]
【The invention's effect】
According to the manufacturing method of the present invention, since a wiring material including an Al film or an alloy film containing Al as a main component is used, generation of hillocks on the Al surface can be suppressed. Therefore, a short circuit between wirings can be reduced when a display device or the like is configured.
[0128]
When the multilayer wiring is used for the scanning signal electrode of the liquid crystal display device, the interlayer dielectric strength between the scanning signal electrode and the video signal electrode increases. As a result, it is possible to reduce the short-circuit defect and reduce the resistance of the scanning signal electrode, thereby achieving an increase in the size and definition of the display screen.
[0129]
Further, when the entire surface of Al is covered with an insulating film containing Al as a base material, Al is not exposed to chemicals and the like, so that corrosion resistance can be ensured and hillock generation on the Al surface is further suppressed. it can.
[0130]
When the external connection terminal is constituted by one metal and a transparent conductive film made of a metal oxide formed thereon, the chemical resistance of the terminal is improved, and the insulating barrier layer formed by the reaction between the transparent conductive film and the metal forms an interface. Is difficult to form. Therefore, an increase in the contact resistance of the connection terminal can be prevented, and a highly reliable connection terminal can be obtained.
[0131]
Such a structure can be formed by etching and removing Al using the insulating film formed on the Al surface as a mask. Therefore, the above-described structure can be formed with only one photomask, and at the same time, the effects of reducing the number of steps, securing corrosion resistance, reducing short-circuit defects, and reducing the resistance of the scanning signal electrode can be obtained.
[0132]
A pixel electrode made of a transparent conductive film is arranged below the semiconductor film and the gate insulating film, and the semiconductor film and the gate insulating film are extended along the video signal electrode as a pattern wider than the video signal electrode, and the pixel electrode pattern , The pixel electrode and the video signal electrode can be separated. In this way, even if the distance between the pixel electrode and the video signal electrode is reduced while preventing the short circuit between the pixel electrode and the video signal electrode, pixel defects due to the short circuit can be reduced. Further, the width of the pixel electrode is increased, and the pixel aperture ratio is improved. Therefore, in addition to features such as a reduction in the number of steps, a high yield, low resistance wiring, and an improvement in the reliability of the terminal portion, a liquid crystal display device with low defects and high luminance can be realized.
[0133]
As a result, in a minimum photolithography process, a liquid crystal display device having a low-resistance scan signal electrode with few hillocks and an external connection terminal with high corrosion resistance, a small pixel defect density, and a large pixel aperture ratio can be obtained. It is possible to simultaneously increase the size, increase the definition, and reduce the cost of the liquid crystal display device.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment of a laminated wiring material according to the present invention.
FIG. 2 is a diagram showing a comparison of surface irregularities of an Al film 11 formed on a glass substrate 1 and a Ta film 10 respectively.
FIG. 3 is a diagram showing an X-ray diffraction pattern of an Al thin film used for the wiring of the present invention in comparison with an X-ray diffraction pattern of a conventional Al film.
FIG. 4 is a diagram showing the relationship between the intensity ratio of the (220) diffraction peak and the (200) diffraction peak obtained from the X-ray diffraction of the Al film and the surface hillock density.
FIG. 5 is a plan view of a scanning signal wiring for a liquid crystal display device formed using the laminated wiring material of the present invention.
6 is a cross-sectional view of an external connection terminal portion of the scanning signal wiring of FIG.
FIG. 7 is a cross-sectional view of the AA plane of FIG. 6 as viewed from the direction of the arrow.
FIG. 8 is a sectional view showing an end of another embodiment of the scanning signal electrode of the liquid crystal display device according to the present invention.
9 is a cross-sectional view of the AA plane of FIG. 8 as viewed from the direction of the arrow.
FIG. 10 is a schematic cross-sectional view of a unit pixel of a liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment shown in FIG.
FIG. 11 is a sectional view of an external connection terminal of a scanning signal electrode of the thin film transistor substrate.
FIG. 12 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
FIG. 13 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
FIG. 14 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
FIG. 15 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
FIG. 16 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.
FIG. 17 is a cross-sectional view of a pixel according to an embodiment in which the wiring material of the present invention is applied to a video signal wiring.
FIG. 18 is a cross-sectional view of a pixel portion of another embodiment of the liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment shown in FIG.
FIG. 19 is a plan view of the embodiment of FIG.
20 is a diagram showing the inside of an a-Si: H film 30 taken along the line AA in FIG. 18; ³¹ P and ¹¹ FIG. 7 is a diagram illustrating a density distribution of B in a depth direction.
21 is a diagram showing the inside of an a-Si: H film 30 in a BB section in FIG. 18; ³¹ P and ¹¹ FIG. 7 is a diagram illustrating a density distribution of B in a depth direction.
FIG. 22 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 23 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 24 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 25 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 26 is a sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 27 is a sectional view showing the manufacturing process of the embodiment in FIG. 18;
FIG. 28 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 29 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;
FIG. 30 is an equivalent circuit of a TFT substrate in the liquid crystal display device of the present invention.
FIG. 31 is an equivalent circuit of another TFT substrate in the liquid crystal display device of the present invention.
FIG. 32 is a diagram showing a schematic cross section of a liquid crystal display device constituted by the thin film semiconductor device according to the present invention.
[Explanation of symbols]
1 Glass substrate
10 Ta electrode
11 Al electrode oriented on (220) plane
13 Pixel electrode
14 Video signal electrode
15 Source electrode
16 capacity electrode
20 Ta ₂ O ₅ film
21 Al ₂ O ₃ film
22 Gate SiN electrode
23 Protected SiN film
30 a-Si: H film
31 n-type a-Si: H film
140 External connection terminal
141, 151, 161 Ta film
142, 152, 162 Al film
200 scanning signal circuit
210 Video signal circuit
505 Polarizing plate
506 liquid crystal layer
507 Color filter
508 Opposing glass substrate
510 Counter electrode
511 Color filter protective film
512 Light shielding film
BL backlight
ORI alignment film
SL sealing material
SIL silver paste material

Claims (3)

A scanning signal electrode formed on an insulating substrate and at least partially covered by an insulating film, a video signal electrode formed to intersect with the scanning signal electrode, and a scan signal electrode and the video signal electrode; A method for manufacturing a liquid crystal display device having a thin film transistor formed near an intersection.
a. A first conductive film of metal and Al or an alloy film containing Al as a main component are laminated on the insulating substrate, and the first conductive film and the Al or Al-based alloy film as a main component are substantially Forming the scanning signal electrode by processing into the same pattern b. Step of forming the insulating film covering a portion of the scanning signal electrode c. A step of removing, from the conductive film forming the scanning signal electrode, Al or an alloy film containing Al as a main component, using the insulating film as a mask, for a terminal portion of the scanning signal electrode connected to an external drive circuit. Characteristic manufacturing method of a liquid crystal display device. The method for manufacturing a liquid crystal display device according to claim 1,
After the step c,
d. A method for manufacturing a liquid crystal display device, comprising a step of forming a transparent conductive film on the first conductive film for the terminal portion. The method for manufacturing a liquid crystal display device according to claim 2,
In the step (d), the transparent conductive film is formed continuously on the insulating film from the terminal portion.

Images