JPH07270821A - Active matrix system tft-lcd and its production - Google Patents

Abstract

PURPOSE:To provide an active matrix system TFT-LCD capable of increasing an auxiliary capacitance without lowering an opening ratio. CONSTITUTION:A polycrystal silicon film 2, a gate oxidized film 3, a gate electrode 4 are formed successively on a quartz substrate 1. In the polycrystal silicon film 2, a drain area 5 and a source area 6 are formed. The source area 6 is connected with the store electrode 7 of an auxiliary capacitance CS formed on the polycrystal silicon film 2 and a display electrode 14. A silicon oxidized film 8 as a dielectric film and the counter electrode 9 of the auxiliary capacitance CS are formed successively on the store electrode 7. An interlayer insulation film 10 is formed on the surface of the whole of them and the display electrode 14 is formed on the film 10. Since the interlayer insulation film 10 on the counter electrode 9 is made thin, the display electrode 14 and the counter electrode 9 are formed adjacently. Thus, since the interlayer insulation film 10 acts as a dielectric film and then a static capacitance is formed in between the display electrode 14 and the counter electrode 9, the auxiliary capacitance CS is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type TFT (Thin Film Transistor) -LCD (Liquid Crystal Display) and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, active matrix systems using TFTs have become the mainstream of high-definition LCDs.

The active matrix system is a system in which a switch element (pixel control element) and a signal storage element (pixel capacity) are integrated in each pixel to drive the liquid crystal quasi-statically. That is, the video signal voltage from the outside is transferred to the wiring inside the LCD via the drive circuit, and the transferred video signal voltage is stored in each signal storage element via each switch element. Therefore, compared to the simple matrix method in which display is performed only by using the liquid crystal material, in the active matrix method, the switch element and the liquid crystal material can be combined and each can be assigned a role, so that much higher quality display can be achieved. It will be possible. Furthermore, the active matrix type TFT-LCD which uses a transistor with the best characteristics as a switch element is
Method using a diode as a switch element (MIM-
Although it is difficult to manufacture, it is possible to obtain an excellent image quality comparable to that of a CRT, compared to an LCD or MSI-LCD.

FIG. 8 shows a block structure of a general TFT-LCD. The TFT-LCD pixel portion 50 is provided with gate lines (scanning lines) G1 ... Gn, Gn + 1 ... Gm and drain lines (data lines) D1 ... Dn, Dn + 1 ... Dm. The gate wirings and the drain wirings are orthogonal to each other, and pixels are provided in the orthogonal portions. Each gate wiring is connected to the gate driver 51 so that a gate signal (scanning signal) is applied.
In addition, each drain wiring is a data (drain) driver 5
It is connected to 2 and a video signal voltage is applied.

FIG. 9 shows an equivalent circuit of one pixel 60 of the TFT-LCD pixel section 50. Each gate wiring has each TF
The gate of T is connected, and the drain of each TFT is connected to each drain wiring. The display electrode (pixel electrode) of the liquid crystal cell LC and the auxiliary capacitance (storage capacitance) CS are connected to the source of each TFT. This liquid crystal cell L
The signal storage element is composed of C and the auxiliary capacitance CS. The voltage Vcom is applied to the common electrode of the liquid crystal cell LC (the electrode on the opposite side of the display electrode). On the other hand, in the auxiliary capacitance CS, a constant voltage VR is applied to an electrode (hereinafter, referred to as a counter electrode) opposite to an electrode (hereinafter, referred to as a storage electrode) on the side connected to the source of the TFT. The common electrode of the liquid crystal cell LC is an electrode which is literally common to all the pixels 60. And the liquid crystal cell L
Capacitance is formed between the C display electrode and the common electrode. In FIG. 9, only the TFTs connected to the gate line Gn and the drain line Dn are shown. Also,
The counter electrode of the storage capacitor CS may be connected to the adjacent gate wiring Gn + 1.

In the pixel 60 thus constructed,
When the gate wiring Gn is set to a positive voltage and a positive voltage is applied to the gate of the TFT, the TFT turns on. Then, with the video signal voltage applied to the drain wiring Dn, the liquid crystal cell LC
And the auxiliary capacitance CS are charged. On the contrary, when the gate line Gn is set to a negative voltage and a negative voltage is applied to the gate of the TFT, the TFT is turned off, and the voltage applied to the drain line Dn at that time is the electrostatic capacity and the auxiliary capacity of the liquid crystal cell LC. Held by CS.

As described above, the video signal voltage desired to be written to the pixel 60 is applied to the drain wiring to control the voltage of the gate wiring, whereby the pixel 60 can hold an arbitrary video signal voltage. The transmittance of the liquid crystal cell LC changes according to the video signal voltage held by the pixel 60, and an image is displayed.

Here, important characteristics of the pixel 60 are a writing characteristic and a holding characteristic. What is required for the writing characteristics is that a desired video signal voltage is sufficiently supplied to the signal storage element (the liquid crystal cell LC and the auxiliary capacitance CS) within a unit time determined from the specifications of the TFT-LCD pixel section 50. The point is whether you can write to. Further, what is required for the holding characteristic is whether or not the video signal voltage once written in the signal storage element can be held for a required time.

The auxiliary capacitance CS is provided in order to increase the electrostatic capacitance of the signal storage element and improve the writing characteristic and the holding characteristic. That is, the liquid crystal cell L
Due to the structure of C, there is a limit to the increase in capacitance. Therefore, the auxiliary capacitance CS compensates for the shortage of the electrostatic capacitance of the liquid crystal cell LC.

FIG. 10 shows a sectional structure of a conventional pixel 60 using a coplanar type polycrystalline silicon TFT (TFT using polycrystalline silicon as an active layer). An active layer polycrystalline silicon film 2 is formed on a quartz substrate 1. A gate oxide film 3 is formed on the polycrystalline silicon film 2. A gate electrode 4 of the TFT is formed on the gate oxide film 3. A drain region 5 and a source region 6 of the TFT are formed on the polycrystalline silicon film 2. The source region 6 is connected to the storage electrode 7 of the auxiliary capacitor CS formed in the polycrystalline silicon film 2. A silicon oxide film 8 as a dielectric film is formed on the storage electrode 7. On the silicon oxide film 8, the counter electrode 9 of the auxiliary capacitance CS is formed.
Are formed. An interlayer insulating film 10 is formed on the entire surface of these (quartz substrate 1, polycrystalline silicon film 2, gate electrode 4, counter electrode 9). The gate electrode 4, the drain region 5, and the source region 6 are respectively provided with a gate wiring 1 through a contact hole formed in the interlayer insulating film 10.
1, drain electrode (drain wiring) 12, source electrode 1
It is connected with 3. The source region 6 is connected to the display electrode 14 of the liquid crystal cell LC via the same contact hole as the source electrode 13. The display electrode 14 is ITO
It is made of (indium tin oxide) and is formed on the interlayer insulating film 10 above the counter electrode 9.

[0011]

In recent years, further improvement in write characteristics and holding characteristics has been demanded, and in order to satisfy those requirements, it is required to increase the auxiliary capacitance CS. In order to increase the auxiliary capacitance CS in the pixel 60 shown in FIG. 10, the width of the counter electrode 9 may be increased. However, if the width of the counter electrode 9 is widened, the aperture area of the pixel 60 becomes smaller accordingly, the aperture ratio of the TFT-LCD pixel portion 50 is reduced, the screen is darkened, and the image quality is deteriorated.

The present invention has been made in order to solve the above problems, and an object thereof is to increase the auxiliary capacitance and improve the write characteristics and the retention characteristics without lowering the aperture ratio. It is to provide an active matrix type TFT-LCD. Another object of the present invention is to provide a simple and easy manufacturing method of such an active matrix type TFT-LCD.

[0013]

According to a first aspect of the present invention, in an active matrix type TFT-LCD including a TFT, a liquid crystal cell and an auxiliary capacitance, a counter electrode of an electrode connected to the TFT in the auxiliary capacitance is provided. The gist is that an electrostatic capacitance is formed between the liquid crystal cell and the display electrode.

According to a second aspect of the invention, the TFT and one electrode formed on the active layer of the TFT are connected to the source of the TFT, and the counter electrode is formed via the one electrode and the dielectric film. Storage capacity, its storage capacity and TF
In an active matrix type TFT-LCD including an interlayer insulating film formed on T and a display electrode of a liquid crystal cell formed on the interlayer insulating film, electrostatic discharge is provided between the counter electrode and the display electrode. It is the gist of that the capacity is formed.

According to a third aspect of the present invention, in the second aspect of the invention, the interlayer insulating film between the counter electrode and the display electrode is formed to have an appropriate thickness, whereby the counter electrode and the display electrode are formed. The gist is that a capacitance is formed between the two.

According to a fourth aspect of the invention, in the second aspect of the invention, the counter electrode is provided by providing a second dielectric film having an appropriate dielectric constant between the counter electrode and the display electrode. The gist is that an electrostatic capacitance is formed between the display electrode and the display electrode.

A fifth aspect of the present invention relates to the method of manufacturing an active matrix type TFT-LCD according to the third aspect, which comprises a step of forming a silicon layer on an insulating substrate,
A step of forming a TFT having the silicon layer as an active layer and forming one electrode of an auxiliary capacitor connected to the source of the TFT on the silicon layer, and forming a dielectric film on one electrode of the auxiliary capacitor Forming step, forming a counter electrode of the auxiliary capacitor on the dielectric film, forming an interlayer insulating film on the counter electrode and the TFT, and etching the interlayer insulating film on the counter electrode. The gist of the invention is that it includes a step of forming a predetermined film thickness and a step of forming a display electrode of a liquid crystal cell on the interlayer insulating film.

According to a sixth aspect of the present invention, there is provided a method of manufacturing an active matrix type TFT-LCD according to the fourth aspect, which comprises a step of forming a silicon layer on an insulating substrate,
A step of forming a TFT having the silicon layer as an active layer and forming one electrode of an auxiliary capacitance connected to the source of the TFT in the silicon layer, and a first dielectric on one electrode of the auxiliary capacitance The step of forming the body film, the step of forming the counter electrode of the auxiliary capacitor on the dielectric film, the step of forming the interlayer insulating film on the counter electrode and the TFT, and the step of forming the interlayer insulating film on the counter electrode. Etching to expose the counter electrode, forming a second dielectric film on the exposed counter electrode, and forming a display electrode of a liquid crystal cell on the second dielectric film and the interlayer insulating film The point is to have and.

[0019]

According to the first aspect of the invention, the capacitance is formed between the display electrode and the counter electrode without widening the width of the counter electrode. Therefore, the auxiliary capacitance can be increased without lowering the aperture ratio, and the write characteristic and the retention characteristic can be improved.

According to a second aspect of the present invention, the invention according to the first aspect is the coplanar type or stagger type polycrystalline silicon TF.
The invention is applied to an LCD using a T or amorphous silicon TFT, and the same operation and effect as the invention described in claim 1 can be obtained.

According to the third aspect of the present invention, the interlayer insulating film between the counter electrode and the display electrode is made to have an appropriate thickness, so that the interlayer insulating film functions as a dielectric film and the counter electrode and Capacitance can be formed between the display electrode and the display electrode.

According to the fourth aspect of the present invention, by providing the second dielectric film having an appropriate dielectric constant between the counter electrode and the display electrode, electrostatic discharge is provided between the counter electrode and the display electrode. Capacitance can be formed. In this case, by setting the dielectric constant and the film thickness of the second dielectric film to the optimum values, it is possible to obtain the withstand voltage and the electrostatic capacitance required for the auxiliary capacitance.

According to the invention of claim 5, the TFT-LCD of claim 3 can be easily and simply provided only by etching the interlayer insulating film on the counter electrode to a predetermined thickness. Can be manufactured.

According to the invention of claim 6, a step of etching the interlayer insulating film on the counter electrode to expose the counter electrode, and a step of forming a second dielectric film on the exposed counter electrode. The TFT-L according to claim 4, only by providing
The CD can be manufactured easily and easily. In this case, since the second dielectric film is formed after removing all the interlayer insulating film on the counter electrode, the thickness of the second dielectric film can be easily controlled. As a result, it becomes easy to control the withstand voltage and the electrostatic capacitance required for the auxiliary capacitance. Also,
When the interlayer insulating film on the counter electrode is etched, it is not necessary to control the film thickness accurately, which facilitates manufacturing.

[0025]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the same components as those in the conventional example shown in FIGS. 8 to 10 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 shows a sectional structure of a pixel 60 of this embodiment using a coplanar polycrystalline silicon TFT. The present example is different from the conventional example shown in FIG. 10 only in that an electrostatic capacitance is formed between the display electrode 14 of the liquid crystal cell LC and the counter electrode 9 of the auxiliary capacitance CS. The width of the electrode 9 does not change. That is,
In this embodiment, the interlayer insulating film 10 on the counter electrode 9 is thinner than that of the conventional example shown in FIG. 10, and the display electrode 14 and the counter electrode 9 are close to each other. Therefore, the interlayer insulating film 10 on the counter electrode 9 functions as a dielectric film, and a capacitance is formed between the display electrode 14 and the counter electrode 9.
Further, also in this embodiment, the storage electrode 7 of the liquid crystal cell LC is connected to the display electrode 14 via the source region 6 of the TFT, as in the conventional example shown in FIG. Therefore, the electrostatic capacitance formed between the storage electrode 7 and the counter electrode 9 (the auxiliary capacitance CS of the conventional example shown in FIG. 10) and the display electrode 14
And the capacitance formed between the counter electrode 9 and the counter electrode 9 are connected in parallel. Therefore, the auxiliary capacitance CS of this embodiment is increased by the amount of the electrostatic capacitance formed between the display electrode 14 and the counter electrode 9 as compared with the conventional example shown in FIG.

Next, the manufacturing method of this embodiment will be described in sequence. Step 1 (see FIG. 2); quartz substrate 1 by low pressure CVD method
A polycrystalline silicon film 2 is formed on top. Next, the polycrystalline silicon film 2 is etched so as to have a desired shape. Then, the gate oxide film 3 is formed on the polycrystalline silicon film 2 by the thermal oxidation method. Then, a polycrystalline silicon film is formed on the gate oxide film 3 by the low pressure CVD method. The polycrystalline silicon film is etched to form the gate electrode 4. Next, phosphorus ions are implanted into the polycrystalline silicon film 2 by the self-alignment method using the gate electrode 5 as a mask to form the drain region 5 and the source region 6. At this time, the storage electrode 7 is also formed at the same time. Further, heat treatment is performed in a nitrogen atmosphere at about 900 ° C. to activate the implanted phosphorus ions. Then, the silicon oxide film 8 is formed on the storage electrode 7 by the thermal oxidation method. Next, a polycrystalline silicon film is formed on the silicon oxide film 8 by the low pressure CVD method. The polycrystalline silicon film is etched to form the counter electrode 9. Then, the interlayer insulating film 10 made of a silicon oxide film is formed on the entire surface of the device by the CVD method.

Step 2 (see FIG. 2): The etching mask used for forming the counter electrode 9 is diverted and only the interlayer insulating film 10 on the counter electrode 9 is etched to a predetermined film thickness.
At this time, the etching amount is controlled so that the film thickness of the interlayer insulating film 10 on the counter electrode 9 becomes an optimum value that satisfies the withstand voltage and the electrostatic capacitance required for the auxiliary capacitance CS.

Step 3 (see FIG. 3): A contact hole 15 is opened in the interlayer insulating film 10 on the gate electrode 4, the drain region 5 and the source region 6. Step 4 (see FIG. 4): Interlayer insulating film 10 by sputtering method
An ITO film is formed on the ITO film, and the ITO film is etched to form the display electrode 14. At this time, an ITO film is also formed in the contact hole 15 on the source region 6 so that the display electrode 14 and the source region 6 are connected.

Step 5 (see FIG. 1): An aluminum film is formed on the interlayer insulating film 10 by the sputtering method, and the aluminum film is etched to form the drain electrode 12 and the source electrode 13.

As described above, according to this embodiment, the counter electrode 9
The capacitance is formed between the display electrode 14 and the counter electrode 9 without increasing the width of. Therefore, the auxiliary capacitance CS can be increased without lowering the aperture ratio, and the write characteristic and the retention characteristic can be improved. Further, if the size of the auxiliary capacitance CS is the same as the conventional one, the width of the counter electrode 9 can be reduced by the amount of the electrostatic capacitance formed between the display electrode 14 and the counter electrode 9, and the aperture ratio can be reduced. Can also be improved.

The present embodiment can be easily and easily manufactured by adding the step of etching the interlayer insulating film 10 on the counter electrode 9 to the conventional manufacturing step. Further, as an etching mask used when etching the interlayer insulating film 10 on the counter electrode 9 in the process of forming a capacitance between the display electrode 14 and the counter electrode 9, the etching used when the counter electrode 9 is formed. The mask is diverted.
Therefore, only the interlayer insulating film 10 on the counter electrode 9 can be easily etched, and the number of etching masks does not increase as compared with the conventional manufacturing method. (Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 5 shows a coplanar polycrystalline silicon TF.
The cross-sectional structure of the pixel 60 of this embodiment using T is shown. This embodiment differs from the first embodiment shown in FIG. 1 in that
The only difference is that the dielectric film 17 is formed between the display electrode 14 and the counter electrode 9. That is, in the first embodiment, the thin interlayer insulating film 10 on the counter electrode 9 functions as a dielectric film, whereas in the present embodiment, the interlayer insulating film 1 is formed.
A dielectric film 17 is provided separately from 0, and a capacitance is formed between the display electrode 14 and the counter electrode 9.

The manufacturing method of this embodiment is different from the manufacturing method of the first embodiment only in the following steps 2a and 2b.
The other steps are the same as in the first embodiment. Step 2a (see FIG. 5); the etching mask used for forming the counter electrode 9 is diverted, and the interlayer insulating film 1 on the counter electrode 9 is used.
All the 0s are etched to expose the counter electrode 9. That is, the contact hole 16 is opened in the interlayer insulating film 10 on the counter electrode 9.

Step 2b (see FIG. 6); appropriate CVD method (reduced pressure CVD method, atmospheric pressure CVD method, plasma CVD method,
Etc., a silicon oxide film as a dielectric film 17 is deposited on the exposed counter electrode 9 in the contact hole 16. At this time, the film thickness of the dielectric film 17 depends on the auxiliary capacitance CS.
The deposition amount is controlled so as to be an optimum value that satisfies the withstand voltage and the electrostatic capacitance required for the.

As described above, according to this embodiment, in addition to the actions and effects of the first embodiment, the interlayer insulating film 1 on the counter electrode 9 is provided.
Since the dielectric film 17 is formed after all 0s are removed, the film thickness of the dielectric film 17 can be easily controlled. As a result, it becomes easy to control the withstand voltage and the electrostatic capacitance required for the auxiliary capacitance CS.

Further, when the interlayer insulating film 10 on the counter electrode 9 is etched, it is not necessary to control the film thickness accurately, so that the manufacturing is facilitated. The above-described embodiments may be modified as follows, and in that case, the same effects as those of the above-mentioned embodiments can be obtained.

1) In the second embodiment, an appropriate film having a high dielectric constant (silicon nitride film, PSG) is used as the dielectric film 17.
Film, BPSG film, etc.) is used. The silicon nitride film can be formed by a low pressure CVD method or a plasma CVD method, and the PSG film and the BPSG film can be formed by an atmospheric pressure CVD method. In this case, the auxiliary capacitance CS can be further increased by increasing the dielectric constant of the dielectric film 17.

2) By providing irregularities on the surface of the counter electrode 9, the auxiliary capacitance CS is further increased. 3) Replace the quartz substrate 1 with a glass substrate using a low temperature process. For more information on low-temperature processes, see Nikkei Electronics 1994.2.28 (no.602). That is, after forming an amorphous silicon film on a glass substrate, a polycrystalline silicon film of an active layer is obtained from the amorphous silicon film by using a solid phase growth method or a laser annealing method. And ECR plasma CV
A gate oxide film is formed by the D method. In this case, since the glass substrate is cheaper than the quartz substrate and can be easily increased in area, the TFT-LCD pixel portion 50 can be inexpensively increased in size.

4) The silicon oxide film 8 is not thermally oxidized, but
It is formed by an appropriate CVD method (a low pressure CVD method, a normal pressure CVD method, a plasma CVD method, or the like). 5) By replacing the silicon oxide film 8 with an appropriate film having a high dielectric constant (silicon nitride film, PSG film, BPSG film, etc.), the auxiliary capacitance CS is further increased.

6) The interlayer insulating film 10 is not a silicon oxide film but an appropriate film (silicon nitride film, PSG film, BPSG).
Membrane, etc.). 7) In step 1 above, the silicon oxide film 8 is formed simultaneously with the gate oxide film 3, and the counter electrode 9 is formed simultaneously with the gate electrode 4. At the time of ion implantation for forming the drain region 5, the source region 6, and the storage electrode 7, a resist pattern is formed on the polycrystalline silicon film 2 so that ions are not implanted into an unnecessary portion (channel region or the like). To do. In this case, the drain region 5 and the source region 6
However, the number of steps can be reduced.

8) It is applied to an amorphous silicon TFT using an active layer of amorphous silicon instead of a polycrystalline silicon TFT. 9) Stagger type polycrystalline silicon TF instead of coplanar type
Applies to T or amorphous silicon TFT.

Although the respective embodiments of the present invention have been described above, there are the following technical ideas other than the claims which can be understood from the respective embodiments, and in these technical ideas as well,
Similar actions and effects can be obtained.

(A) In the active matrix type TFT-LCD according to the second aspect, the TFT is a coplanar type or stagger type polycrystalline silicon TFT or an amorphous silicon TFT.

(B) In the method of manufacturing an active matrix type TFT-LCD according to claim 5 or 6, the active layer comprises a polycrystalline silicon layer or an amorphous silicon layer, and the TFT is a coplanar type or It is staggered.

By the way, in this specification, the members relating to the constitution of the invention are defined as follows. a) The insulating substrate includes not only a quartz substrate, a glass substrate, a substrate made of any insulating material such as ceramics, but also a metal substrate having an insulating layer on its surface.

B) As the first and second dielectric films,
Not only silicon oxide film, but also silicon nitride film, PSG
It also includes any dielectric film such as a film and a BPSG film. c) As the interlayer insulating film, not only the silicon oxide film,
It also includes any insulating film such as a silicon nitride film, a PSG film, and a BPSG film.

D) The display electrode includes not only an ITO film but also a tin oxide film.

[0049]

As described above in detail, according to the present invention, there is provided an active matrix type TFT-LCD capable of increasing the auxiliary capacitance and improving the writing characteristic and the retaining characteristic without lowering the aperture ratio. can do. Further, it is possible to provide a simple and easy manufacturing method of such an active matrix type TFT-LCD.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a first embodiment embodying the present invention.

FIG. 2 is a cross-sectional view for explaining the manufacturing process of the first embodiment.

FIG. 3 is a sectional view for explaining the manufacturing process for the first embodiment.

FIG. 4 is a sectional view for explaining the manufacturing process for the first embodiment.

FIG. 5 is a sectional view showing the structure of a second embodiment of the present invention.

FIG. 6 is a cross-sectional view for explaining the manufacturing process for the second embodiment.

FIG. 7 is a cross-sectional view for explaining the manufacturing process for the second embodiment.

FIG. 8 is a block circuit diagram showing a configuration of a general TFT-LCD.

9 is a circuit diagram showing one pixel 60 of the TFT-LCD pixel portion 50. FIG.

FIG. 10 is a cross-sectional view showing the structure of a conventional pixel 60.

[Explanation of symbols]

TFT thin film transistor LC liquid crystal cell CS auxiliary capacitance 2 polycrystalline silicon layer 7 storage electrode as an electrode connected to the TFT in the auxiliary capacitance 8 silicon oxide film as a first dielectric film 9 counter electrode 10 interlayer insulating film 14 display electrode 17 Second dielectric film

Claims (6)

[Claims] 1. An active matrix type TFT-LCD including a TFT, a liquid crystal cell and an auxiliary capacitance,
Active matrix type TFT in which a capacitance is formed between the counter electrode (9) of the electrode (7) connected to the TFT in the auxiliary capacitance (CS) and the display electrode (14) of the liquid crystal cell (LC). -LCD. 2. The TFT and one electrode (7) formed on the active layer (2) of the TFT are connected to the source (6) of the TFT, and the one electrode and the dielectric film (8) are interposed. Capacitor (CS) having a counter electrode (9) formed thereon, an interlayer insulating film (10) formed on the auxiliary capacitor and the TFT, and a liquid crystal cell (LC) formed on the interlayer insulating film. Active matrix type T including display electrodes (14) of
In the FT-LCD, an active matrix type TFT-LCD, wherein a capacitance is formed between the counter electrode (9) and the display electrode (14). 3. The active matrix type TFT-LCD according to claim 2, wherein the interlayer insulating film (10) between the counter electrode (9) and the display electrode (14) has an appropriate thickness. An active matrix TFT-LCD characterized in that a capacitance is formed between the counter electrode and the display electrode. 4. The active matrix type TFT-LCD according to claim 2, wherein a second dielectric film (17) having an appropriate dielectric constant is provided between the counter electrode (9) and the display electrode (14). An active matrix type TFT-LCD characterized in that a capacitance is formed between the counter electrode and the display electrode by providing. 5. A step of forming a silicon layer (2) on an insulating substrate (1), a TFT having the silicon layer as an active layer, and an auxiliary capacitor connected to the source of the TFT on the silicon layer. A step of forming one electrode (7) of (CS), a step of forming a dielectric film (8) on one electrode (7) of the auxiliary capacitor, and an auxiliary step on the dielectric film (8). Forming the counter electrode (9) of the capacitor, forming the interlayer insulating film (10) on the counter electrode and the TFT, and etching the interlayer insulating film on the counter electrode to a predetermined thickness The method for manufacturing an active matrix type TFT-LCD according to claim 3, comprising a step and a step of forming a display electrode (14) of a liquid crystal cell (LC) on the interlayer insulating film. 6. A step of forming a silicon layer (2) on an insulating substrate (1), a TFT having the silicon layer as an active layer, and an auxiliary capacitor connected to the source of the TFT on the silicon layer. A step of forming one electrode (7) of (CS), a step of forming a first dielectric film (8) on one electrode (7) of the auxiliary capacitor, and the dielectric film (8) A step of forming a counter electrode (9) of a storage capacitor on the top, a step of forming an interlayer insulating film (10) on the counter electrode and the TFT, and by etching the interlayer insulating film on the counter electrode, A step of exposing, a step of forming a second dielectric film (17) on the exposed counter electrode, and a liquid crystal cell (LC) on the second dielectric film and the interlayer insulating film.
Forming a display electrode (14) according to claim 4.
5. A method for manufacturing an active matrix type TFT-LCD as described in 1.