JP2004045811A - Liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form the gate insulating film of a driving transistor and the capacitor insulating film of an auxiliary capacitor out of insulating films different from each other in a liquid crystal display. <P>SOLUTION: The liquid crystal display device is manufactured by filling the gap between two substrates disposed opposing to each other with a liquid crystal, and by forming a driving transistor and an auxiliary capacitor on one substrate. The gate insulating film of the driving transistor is deposited on the surface of the substrate, the gate insulating film is partially removed and patterned into a specified pattern, and then the capacitor insulating film of the auxiliary capacitor is formed from a material different from that of the gate insulating film in the area where the gate insulating film is removed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device and a method for manufacturing the same.
[0002]
[Prior art]
A conventional liquid crystal display device has a configuration in which a transparent liquid crystal driving substrate made of glass or quartz and a counter substrate are arranged to face each other via a spacer or a sealing material, and a liquid crystal is filled between the two substrates. A plurality of transparent electrodes facing the liquid crystal driving substrate and the opposing substrate are formed in a lattice arrangement, respectively, and a predetermined driving signal is applied between the two transparent electrodes to change the light transmittance of the liquid crystal between the two transparent electrodes. Thus, various displays are performed.
[0003]
Here, as shown in FIG. 5, a driving transistor 102 (thin film transistor: TFT (Thin Film Transistor)) for selectively applying a predetermined driving signal to each transparent electrode 101 is formed on the liquid crystal driving substrate 100. In addition, an auxiliary capacitor 103 for stabilizing the display operation by stably holding the charge stored in the capacitor formed by the transparent electrode 101 for a certain time is formed. The transparent electrodes 101 are connected in series, the auxiliary capacitor 103 is connected between the source terminal of each driving transistor 102 and the ground line 104, and the drain terminals of the driving transistors 102 arranged in the vertical direction are connected to each other. Drive transistors connected by a drive signal line 105 and juxtaposed in the horizontal direction Connecting the gate terminals of the capacitor 102 by the selection signal line 106.
[0004]
Then, the liquid crystal display device 107 selectively supplies a driving signal to one of the transparent electrodes 101 connected to the driving transistor 102 by a selection signal supplied through the selection signal line 106 and a driving signal supplied through the driving signal line 105. Is applied to perform display at the pixel.
[0005]
The liquid crystal drive substrate 100 of the liquid crystal display device 107 was manufactured as follows (see FIG. 6).
[0006]
First, as shown in FIG. 6A, a polysilicon film 109 having a predetermined shape is formed on the upper surface of a glass substrate.
[0007]
Next, as shown in FIG. 6B, an insulating film 110 (oxide film) having a predetermined shape is formed on the upper surface of the polysilicon film 109, and a predetermined position of the insulating film 110 (a position where the driving transistor 102 is formed). Is doped with arsenic or phosphorus.
[0008]
Next, as shown in FIG. 6C, a gate electrode 111 having a predetermined shape and a capacitor are formed by a polysilicon film at predetermined positions on the upper surface of the insulating film 110 (the position where the driving transistor 102 is formed and the position where the auxiliary capacitor 103 is formed). An electrode 112 is formed.
[0009]
Next, as shown in FIG. 6D, an interlayer insulating film 113 (PSG film) is formed on the upper surface of the glass substrate 108, and a contact communicating with the polysilicon film 109 is formed on a part of the interlayer insulating film 113. A hole 114 is formed, and an aluminum wiring 115 (drive signal line 105) is formed in the contact hole 114.
[0010]
Next, as shown in FIG. 6E, an interlayer insulating film 116 (PSG film) is further formed on the upper surface of the interlayer insulating film 113, and a contact hole 117 communicating with the polysilicon film 109 is formed at a predetermined position. I do.
[0011]
Finally, as shown in FIG. 6F, the transparent electrode 101 is formed at a predetermined position on the upper surface of the interlayer insulating film 116 by using an ITO film (Indium-Tin Oxide film).
[0012]
As described above, in the conventional liquid crystal display device 107, the insulating film 110 is formed on the upper surface of the polysilicon film 109, and the gate electrode 111 of the driving transistor 102 and the capacitor electrode 112 of the auxiliary capacitor 103 are formed on the upper surface of the insulating film 110. Had formed. That is, the gate insulating film of the driving transistor 102 and the capacitor insulating film of the auxiliary capacitor 103 are formed by the common insulating film 110.
[0013]
Here, as shown in FIG. 6F, the portion where the driving transistor 102 and the auxiliary capacitor 103 are formed is a non-transmissive region 118 through which light does not pass, and the other portion is a transmissive region through which light passes. 119.
[0014]
[Problems to be solved by the invention]
However, in general, the liquid crystal display device can increase the area of the transmission region by reducing the area of the non-transmission region, and can increase the area of the transmission region by increasing the area of the transmission region. Although high brightness can be achieved, in the above-described conventional liquid crystal display device 107, the gate insulating film of the driving transistor 102 and the capacitor insulating film of the auxiliary capacitor 103 are formed by the common insulating film 110. In addition, the area of the non-transmissive region 118 cannot be reduced, and the luminance of the liquid crystal display device 107 cannot be increased by increasing the area of the transmissive region 119. This was due to the reasons described below.
[0015]
That is, in order to reduce the area of the non-transmissive region 118, it is necessary to reduce the area occupied by the auxiliary capacitor 103 in the non-transmissive region 118. On the other hand, to stabilize the display operation, it is necessary to secure a predetermined capacitance as the auxiliary capacitor 103. Therefore, in order to increase the brightness of the liquid crystal display device 107 while considering the stability of the display operation, it is necessary to reduce the occupied area while securing the capacitance of the auxiliary capacitor 103 to a predetermined value or more. As the method, a method of reducing the thickness of the capacitor insulating film of the auxiliary capacitor 103 or a method of increasing the dielectric constant of the capacitor insulating film of the auxiliary capacitor 103 can be considered.
[0016]
However, in the conventional liquid crystal display device 107, since the gate insulating film of the driving transistor 102 and the capacitor insulating film of the auxiliary capacitor 103 are formed by the common insulating film 110, the capacitor insulating film of the auxiliary capacitor 103 In the case where the thickness is reduced, even the gate insulating film of the driving transistor 102 becomes thinner, the withstand voltage of the driving transistor 102 is reduced, and the reliability of the liquid crystal display device 107 may be reduced. On the other hand, when the dielectric constant of the capacitor insulating film of the auxiliary capacitor 103 is increased by using a silicon nitride film having a high dielectric constant instead of the silicon oxide film as the insulating film 110, the gate oxide of the driving transistor 102 is reduced. A silicon nitride film must be used as the film, and the driving transformer Leakage current Star 102 ends up increasing, whereby the reliability of the liquid crystal display device 107 there is a risk of reducing also.
[0017]
As described above, in the above-described conventional liquid crystal display device 107, since the gate insulating film of the driving transistor 102 and the capacitor insulating film of the auxiliary capacitor 103 are formed by the common insulating film 110, the area of the transmission region 119 is increased. However, it was not possible to increase the brightness of the liquid crystal display device 107 due to the increase in the brightness.
[0018]
On the other hand, by forming the gate insulating film of the driving transistor and the capacitor insulating film of the auxiliary capacitor by separate insulating films, the area of the non-transmissive region is reduced, and the area of the transmissive region is increased by that amount. It is also conceivable to increase the brightness of the image. As a method therefor, a method of laminating the driving transistor and the auxiliary capacitor by forming the auxiliary capacitor below the driving transistor, or forming the auxiliary capacitor in a vertical direction (depth direction) of the semiconductor substrate. Thus, a method of verticalizing the auxiliary capacitor can be considered.
[0019]
However, the method of laminating the driving transistor and the auxiliary capacitor and the method of vertically forming the auxiliary capacitor complicate the manufacturing process of the liquid crystal display device, and may increase the manufacturing cost of the liquid crystal display device. there were.
[0020]
As described above, when the gate insulating film of the driving transistor and the capacitor insulating film of the auxiliary capacitor are formed of different insulating films, the manufacturing cost of the liquid crystal display device increases, and it has been difficult to put the liquid crystal display device to practical use.
[0021]
[Means for Solving the Problems]
Therefore, according to the present invention, in a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one substrate, a capacitor insulating film of the auxiliary capacitor is provided. Has been formed of a material different from the gate insulating film in a portion where the gate insulating film of the driving transistor formed on the surface of the substrate is partially removed.
[0022]
Further, in a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one substrate, a gate insulating film of the driving transistor is formed on the substrate. Is formed of a material different from the capacitor insulating film in a portion where the capacitor insulating film of the auxiliary capacitor formed on the surface is partially removed.
[0023]
Further, the capacitor insulating film is formed of a material having a higher dielectric constant than the gate insulating film.
[0024]
In addition, in a method for manufacturing a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one of the substrates, the driving transistor is provided on the surface of the substrate. A gate insulating film is formed, and a part of the gate insulating film is removed and patterned into a predetermined shape. Then, an auxiliary capacitor made of a material different from that of the gate insulating film is formed in a portion where the gate insulating film is removed. A capacitor insulating film is formed.
[0025]
Further, in a method for manufacturing a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one substrate, an auxiliary capacitor is formed on the surface of the substrate. A capacitor insulating film is formed, a part of the capacitor insulating film is removed and patterned into a predetermined shape, and then a part of the driving transistor made of a material different from the capacitor insulating film is formed in a portion where the capacitor insulating film is removed. A gate insulating film is formed.
[0026]
Further, the capacitor insulating film is formed of a material having a higher dielectric constant than the gate insulating film.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
In the liquid crystal display device according to the present invention, a transparent liquid crystal driving substrate made of glass or quartz or the like and a counter substrate are arranged so as to face each other via a spacer or a sealing material, and a liquid crystal is filled between the two substrates. A plurality of transparent electrodes facing a substrate and a counter substrate are formed in a grid array.
[0028]
Like a conventional liquid crystal display device, a driving transistor (thin film transistor: TFT (Thin Film Transistor)) for selectively applying a predetermined driving signal to each transparent electrode is formed on the liquid crystal driving substrate, and a transparent transistor is formed. An auxiliary capacitor for stabilizing the display operation by stably holding the charge stored in the capacitor formed by the electrodes for a certain period of time is formed.A transparent electrode is connected in series to the source terminal of each driving transistor, and , An auxiliary capacitor is connected between the source terminal of each driving transistor and the ground line, and the drain terminals of the driving transistors arranged vertically are connected by a drive signal line, and are juxtaposed horizontally. The gate terminals of the driving transistors are connected by a selection signal line.
[0029]
The liquid crystal display device according to the present invention is characterized by the structure of the liquid crystal driving substrate and the manufacturing method.
[0030]
That is, in the liquid crystal driving substrate of the liquid crystal display device according to the present invention, after the gate insulating film of the driving transistor is formed on the surface of the liquid crystal driving substrate, a part of the gate insulating film is removed and patterned into a predetermined shape. Thereafter, a capacitor insulating film of an auxiliary capacitor made of a material different from that of the gate insulating film is formed in a portion where the gate insulating film is removed.
[0031]
Further, the liquid crystal driving substrate was formed by forming a capacitor insulating film of an auxiliary capacitor on the surface of the liquid crystal driving substrate, then removing a part of the capacitor insulating film and patterning it into a predetermined shape, and then removing the capacitor insulating film. It is manufactured by forming a gate insulating film of a driving transistor made of a material different from that of the capacitor insulating film in a portion.
[0032]
As described above, according to the present invention, the manufacturing method of the conventional liquid crystal display device can be manufactured on an extension of the conventional manufacturing technology by appropriately combining and using the manufacturing method, thereby increasing the manufacturing cost of the liquid crystal display device. The gate insulating film of the driving transistor and the capacitor insulating film of the auxiliary capacitor can be formed of different insulating films while suppressing the effect as much as possible.
[0033]
In particular, when the capacitor insulating film is formed of a material having a higher dielectric constant than the gate insulating film, the occupied area can be reduced as much as possible while securing the capacity of the auxiliary capacitor. And the area of the transmissive region can be increased by that amount, and the brightness of the liquid crystal display device can be increased.
[0034]
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0035]
[Embodiment 1]
In the liquid crystal display device 1 according to the first embodiment of the present invention, as shown in FIG. 1, after forming a gate insulating film 4 of a driving transistor 3 on a surface of a liquid crystal driving substrate 2, A part manufactured by removing a part and patterning it into a predetermined shape, and then forming a capacitor insulating film 6 of an auxiliary capacitor 5 made of a material different from that of the gate insulating film 4 in a part where the gate insulating film 4 is removed. It is.
[0036]
Hereinafter, a specific method for manufacturing the liquid crystal driving substrate 2 will be described.
[0037]
First, as shown in FIG. 1A, a polysilicon film 8 having a predetermined thickness is formed on the upper surface of a glass substrate 7, and then a portion is removed by photolithography to be patterned into a predetermined shape. Here, the polysilicon film 8 is formed by a low-pressure CVD (Chemical Vapor Deposition) method using only monosilane, and then a predetermined concentration of phosphorus or boron is added to reduce the film resistance. The film may be formed by a CVD method using a gas such as monosilane and phosphine / diborane at the same time.
[0038]
Next, as shown in FIG. 1B, a silicon oxide film to be a gate insulating film 4 of the driving transistor 3 is formed on the upper surface of the polysilicon film 8 to a predetermined thickness. Here, the gate insulating film 4 is formed using heat treatment or a reaction between a silane-based gas and oxygen. Further, the gate insulating film 4 is not limited to the silicon oxide film, and any insulating film may be used.
[0039]
Next, as shown in FIG. 1C, a part of the gate insulating film 4 is removed by etching and patterned into a predetermined shape, and thereafter, a predetermined position of the gate insulating film 4 (a position where the driving transistor 3 is formed) ) Is doped with a predetermined concentration of arsenic or phosphorus. Here, the etching may be wet etching or dry etching.
[0040]
Next, as shown in FIG. 1D, a silicon nitride film to be a capacitor insulating film 6 of the auxiliary capacitor 5 is formed on the upper surface of the gate insulating film 4 to a predetermined thickness. Here, the capacitor insulating film 6 is made of monosilane or SiH ₂ Cl ₂ And a CVD method using ammonia. Further, the capacitor insulating film 6 is not limited to a silicon nitride film, and any insulating film may be used. However, a material having a higher dielectric constant is preferable, and a material having a higher dielectric constant than the gate insulating film 4 is particularly preferable. More preferred.
[0041]
Next, as shown in FIG. 1E, a part of the capacitor insulating film 6 other than the part from which the gate insulating film 4 is removed is removed by etching, and is patterned into a predetermined shape. Here, the etching may be dry etching using radicals or wet etching using phosphoric acid or the like.
[0042]
Next, as shown in FIG. 1F, the gate insulating film 4 is oxidized to improve the breakdown voltage of the gate insulating film 4 and remove the damage. 4 is formed on the upper surface of the capacitor 4 and the upper surface of the capacitor insulating film 6 of the auxiliary capacitor 5 with a predetermined thickness, and then is partially removed by photolithography to be patterned into a predetermined shape. The gate electrode 9 is formed on the upper surface of the gate insulating film 4 and the capacitor electrode 10 is formed on the upper surface of the capacitor insulating film 6 of the auxiliary capacitor 5. Here, the gate electrode 9 and the capacitor electrode 10 are not limited to the polysilicon film, but may be a tungsten film, a tungsten silicide film, or a film in which these are stacked with a polysilicon film.
[0043]
Next, as shown in FIG. 2A, an interlayer insulating film 11 made of a phosphorus glass film (PSG film: Phosphorus Silicate Glass film) is formed on the upper surface of the glass substrate 7 and one of the interlayer insulating films 11 is formed. In this portion, a contact hole 12 communicating with the polysilicon film 8 is formed, and an aluminum wiring 13 (drive signal line) is formed in the contact hole 12.
[0044]
Next, as shown in FIG. 2B, an interlayer insulating film 14 (PSG film) is further formed on the upper surface of the interlayer insulating film 11, and a contact hole 15 communicating with the polysilicon film 8 is formed at a predetermined position. I do.
[0045]
Finally, as shown in FIG. 2C, a transparent electrode 16 made of an ITO film (Indium-Tin Oxide film) is formed at a predetermined position on the upper surface of the interlayer insulating film 14.
[0046]
Here, as shown in FIG. 2C, the portion where the driving transistor 3 and the auxiliary capacitor 5 are formed is a non-transmissive region 17 through which light does not pass, and the other portion is a transmissive region through which light passes. It is 18.
[0047]
As described above, after the gate insulating film 4 of the driving transistor 3 is formed on the surface of the liquid crystal driving substrate 2, a part of the gate insulating film 4 is removed and patterned into a predetermined shape. The capacitor insulating film 6 of the auxiliary capacitor 5 made of a material different from that of the gate insulating film 4 is formed in the portion where the gate insulating film 4 has been removed. The liquid crystal display device 1 in which the gate insulating film 4 of the transistor 3 is partially removed and made of a material different from that of the gate insulating film 4 can be manufactured.
[0048]
Such a liquid crystal display device 1 can be manufactured on an extension of the conventional manufacturing technology by appropriately combining and using a conventional method of manufacturing a liquid crystal display device (a film forming step and an etching step). The gate insulating film 4 of the driving transistor 3 and the capacitor insulating film 6 of the auxiliary capacitor 5 can be formed of insulating films of different materials while suppressing an increase in the manufacturing cost of the display device 1 as much as possible.
[0049]
In particular, by forming the capacitor insulating film 6 with a material having a higher dielectric constant than the gate insulating film 4, the area occupied by the auxiliary capacitor 5 in the liquid crystal driving substrate 2 while securing the capacity of the auxiliary capacitor 5 is as large as possible. As a result, the area of the non-transmissive region 17 can be reduced, and the area of the transmissive region 18 can be increased accordingly, so that the brightness of the liquid crystal display device 1 can be increased.
[0050]
[Embodiment 2]
As shown in FIG. 3, the liquid crystal display device 21 according to the second embodiment of the present invention forms the capacitor insulating film 24 of the auxiliary capacitor 23 on the surface of the liquid crystal driving substrate 22 and then forms one of the capacitor insulating films 24. The gate insulating film of the driving transistor 25 made of a material different from that of the capacitor insulating film 24 is formed on the portion where the capacitor insulating film 24 has been removed, by removing the portion and patterning into a predetermined shape. It is.
[0051]
Hereinafter, a specific method for manufacturing the liquid crystal drive substrate 22 will be described.
[0052]
First, as shown in FIG. 3A, a polysilicon film 28 having a predetermined thickness is formed on the upper surface of the glass substrate 27, and then a portion is removed by photolithography to be patterned into a predetermined shape. Here, the polysilicon film 28 is formed by a low-pressure CVD (Chemical Vapor Deposition) method using only monosilane, and then a predetermined concentration of phosphorus or boron is added to reduce the film resistance. The film may be formed by a CVD method using a gas such as monosilane and phosphine / diborane at the same time.
[0053]
Next, as shown in FIG. 3B, a silicon oxide film 29 having a predetermined thickness is formed on the upper surface of the polysilicon film.
[0054]
Next, as shown in FIG. 3C, a silicon nitride film to be a capacitor insulating film 24 of the auxiliary capacitor 23 is formed with a predetermined thickness. Here, the capacitor insulating film 24 is made of monosilane or SiH ₂ Cl ₂ And a CVD method using ammonia. Further, the capacitor insulating film 24 is not limited to a silicon nitride film, and any insulating film may be used. However, a material having a high dielectric constant is preferable, and in particular, a material having a higher dielectric constant than a gate insulating film 26 described later. Materials are preferred. Further, it is preferable that the capacitor insulating film 24 be made of a material having a lower oxidation coefficient than silicon in consideration of an oxidation process in forming a gate insulating film 26 described later.
[0055]
Next, as shown in FIG. 3D, a part of the capacitor insulating film 24 is removed by etching and patterned into a predetermined shape. Here, the etching may be dry etching using radicals or wet etching using phosphoric acid or the like. In particular, in the case of chemical dry etching using fluorine radicals, the silicon oxide film 29 is an etching stopper. , And can protect the polysilicon film 28.
[0056]
Next, as shown in FIG. 3E, a silicon oxide film to be the gate insulating film 26 of the driving transistor 25 is formed on the upper surface of the polysilicon film 28 and at a portion where the capacitor insulating film 24 is removed. Then, a predetermined concentration (arrangement position of the driving transistor 25) of the gate insulating film 26 is doped with a predetermined concentration of arsenic or phosphorus. Here, as the gate insulating film 26, an oxide film having a predetermined shape is formed by an oxidation process of heating in an oxygen atmosphere. Accordingly, the upper surface of the capacitor insulating film 24 is also oxidized, so that the withstand voltage of the capacitor insulating film 24 can be improved, and the gate insulating film 26 does not need to be patterned by etching. 26 can be prevented from occurring as much as possible. Since the growth rate of the oxide film is lower on the upper surface of the capacitor insulating film 24 made of a silicon nitride film than on the upper surface of the polysilicon film 28, the upper surface of the polysilicon film 28 is formed on the upper surface of the capacitor insulating film 24. A thinner oxide film is formed. Further, the gate insulating film 26 is not limited to the silicon oxide film, and any insulating film may be used.
[0057]
Next, as shown in FIG. 3F, after a polysilicon film is formed to a predetermined thickness on the upper surface of the gate insulating film 26 of the driving transistor 25 and the upper surface of the capacitor insulating film 24 of the auxiliary capacitor 23, The gate electrode 30 is formed on the upper surface of the gate insulating film 26 of the driving transistor 25 by patterning into a predetermined shape by removing a part by photolithography, and the capacitor electrode is formed on the upper surface of the capacitor insulating film 24 of the auxiliary capacitor 23. 31 are formed. Here, the gate electrode 30 and the capacitor electrode 31 are not limited to the polysilicon film, and may be a tungsten film, a tungsten silicide film, or a film in which these are stacked with a polysilicon film.
[0058]
Next, as shown in FIG. 4A, on the upper surface of the glass substrate 27, an interlayer insulating film 32 made of a phosphorus glass film (PSG film: Phosphous Silicate Glass film) is formed. A contact hole 33 communicating with the polysilicon film 28 is formed in the portion, and an aluminum wiring 34 (drive signal line) is formed in the contact hole 33.
[0059]
Next, as shown in FIG. 4B, an interlayer insulating film 35 (PSG film) is further formed on the upper surface of the interlayer insulating film 32, and a contact hole 36 communicating with the polysilicon film 28 is formed at a predetermined position. I do.
[0060]
Finally, as shown in FIG. 4C, a transparent electrode 37 made of an ITO film (Indium-Tin Oxide film) is formed at a predetermined position on the upper surface of the interlayer insulating film 35.
[0061]
Here, as shown in FIG. 4C, the portion where the driving transistor 3 and the auxiliary capacitor 5 are formed is a non-transmissive region 38 through which light does not pass, and the other portion is a transmissive region through which light passes. It is 39.
[0062]
As described above, after the capacitor insulating film 24 of the auxiliary capacitor 23 is formed on the surface of the liquid crystal driving substrate 22, a part of the capacitor insulating film 24 is removed and patterned into a predetermined shape. By forming the gate insulating film 26 of the driving transistor 25 made of a material different from that of the capacitor insulating film 24 in the removed portion, the gate insulating film 26 of the driving transistor 25 was formed on the surface of the liquid crystal driving substrate 22. It is possible to manufacture the liquid crystal display device 21 in which a part of the auxiliary capacitor 23 from which the capacitor insulating film 24 is partially removed is formed of a material different from that of the capacitor insulating film 24.
[0063]
Such a liquid crystal display device 21 can be manufactured on an extension of the conventional manufacturing technology by appropriately combining and using a conventional manufacturing method of a liquid crystal display device (a film forming step and an etching step). The gate insulating film 26 of the driving transistor 25 and the capacitor insulating film 24 of the auxiliary capacitor 23 can be formed of insulating films of different materials while suppressing an increase in the manufacturing cost of the display device 21 as much as possible.
[0064]
In particular, by forming the capacitor insulating film 24 with a material having a higher dielectric constant than the gate insulating film 26, the area occupied by the auxiliary capacitor 23 in the liquid crystal drive substrate 22 while securing the capacity of the auxiliary capacitor 23 is as small as possible. As a result, the area of the non-transmissive region 38 can be reduced, and the area of the transmissive region 39 can be increased accordingly, so that the brightness of the liquid crystal display device 21 can be increased.
[0065]
【The invention's effect】
The present invention is implemented in the form described above, and has the following effects.
[0066]
That is, according to the present invention, it is possible to manufacture the liquid crystal display device on an extension of the conventional manufacturing technology by appropriately combining the conventional manufacturing methods of the liquid crystal display device, thereby increasing the manufacturing cost of the liquid crystal display device. The gate insulating film of the driving transistor and the capacitor insulating film of the auxiliary capacitor can be formed of different insulating films, while suppressing as much as possible.
[0067]
In particular, when the capacitor insulating film is formed of a material having a higher dielectric constant than the gate insulating film, the area occupied by the auxiliary capacitor can be reduced as much as possible while securing the capacity of the auxiliary capacitor. The area of the non-transmissive area can be reduced, and the area of the transmissive area can be increased accordingly, so that the brightness of the liquid crystal display device can be increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a method (first half) of manufacturing a liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is an explanatory view showing a method (second half) of manufacturing the liquid crystal display device according to the first embodiment of the present invention.
FIG. 3 is an explanatory view illustrating a method (first half) of manufacturing a liquid crystal display device according to Embodiment 2 of the present invention.
FIG. 4 is an explanatory view showing a method (second half) of manufacturing the liquid crystal display device according to the second embodiment of the present invention.
FIG. 5 is an equivalent circuit diagram of a liquid crystal display device.
FIG. 6 is an explanatory view showing a method for manufacturing a conventional liquid crystal display device.
[Explanation of symbols]
1,21 liquid crystal display
2,22 LCD drive board
3,25 Driving transistor
4,26 gate insulating film
5,23 Auxiliary capacitor
6,24 Capacitor insulating film
7,27 glass substrate
8,28 polysilicon film
9,30 Gate electrode
10,31 Capacitor electrode
11,14,32,35 interlayer insulating film
12, 15, 33, 36 contact holes
13,34 Aluminum wiring
16,37 transparent electrode
17,38 Non-transparent area
18, 39 Transmission area
29 Silicon oxide film

Claims (6)

In a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one substrate,
A liquid crystal display device wherein the capacitor insulating film of the auxiliary capacitor is formed of a material different from the gate insulating film in a portion where the gate insulating film of the driving transistor formed on the surface of the substrate is partially removed. In a liquid crystal display device in which a liquid crystal is filled between two substrates arranged opposite to each other and a driving transistor and an auxiliary capacitor are formed on one substrate,
A liquid crystal display device, wherein a gate insulating film of a driving transistor is formed of a material different from that of the capacitor insulating film at a portion where a capacitor insulating film of an auxiliary capacitor formed on a surface of a substrate is partially removed. 3. The liquid crystal display device according to claim 1, wherein the capacitor insulating film is formed of a material having a higher dielectric constant than a gate insulating film. In a method for manufacturing a liquid crystal display device, a liquid crystal is filled between two substrates arranged opposite to each other, and a driving transistor and an auxiliary capacitor are formed on one of the substrates.
A gate insulating film of the driving transistor is formed on the surface of the substrate, and a part of the gate insulating film is removed and patterned into a predetermined shape. A method for manufacturing a liquid crystal display device, comprising forming a capacitor insulating film of an auxiliary capacitor made of a different material. In a method for manufacturing a liquid crystal display device, a liquid crystal is filled between two substrates arranged opposite to each other, and a driving transistor and an auxiliary capacitor are formed on one of the substrates.
A capacitor insulating film of the auxiliary capacitor is formed on the surface of the substrate, and a part of the capacitor insulating film is removed and patterned into a predetermined shape. A method for manufacturing a liquid crystal display device, comprising forming a gate insulating film of a driving transistor made of a material. The method according to claim 4, wherein the capacitor insulating film is formed of a material having a higher dielectric constant than a gate insulating film.

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