JP2000330136A - Electrooptical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make reducible unnecessary connection with external peripheral circuits as much as possible and remarkably improvable the manufacturing yield, and to make a picture brighter by allowing a pixel matrix to have a function for driving pixel electrodes connected to TFTs and allowing a first peripheral circuit and a second peripheral circuit to have functions other than functions for driving the pixel electrodes. SOLUTION: In a liquid crystal display device having an m×n circuit constitution, only the part 1 of an analog switching array circuit in parts of peripheral circuits connected to wirings in X direction are made to be TFTs similarly in the active elements provided in a pixel element 6. Moreover, only the part 2 of an analog switching array circuit in parts of peripheral circuits connected to wirings of a Y direction is also made to be TFTs and parts of other peripheral circuits are connected to a substrate with ICs 4 by a COG method. Here, parts of peripheral circuits which are made to be TFTs are formed as CTFTs(complementary type TFTs) similarly in the active elements provided in the pixels. Thus, the number of connection parts is considerably reduced and the reliability of this display device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device formed using thin film transistors.

[0002]

2. Description of the Related Art CRTs are used as displays for OA equipment and the like.
Instead, flat displays have been attracting attention, and expectations for larger areas have been particularly strong. As other applications of flat displays, development of wall-mounted TVs is also proceeding at a rapid pace. Also, demands for flat display colorization and high definition have been considerably increased.

A liquid crystal display device is known as a typical example of the flat display. In this method, an electric field is applied to a liquid crystal composition held between a pair of glass substrates with an electrode interposed therebetween to change the state of the liquid crystal composition, and display is performed by utilizing the difference between the states. In order to drive the liquid crystal, there are a type provided with a thin film transistor (hereinafter referred to as a TFT) and other switching elements, and a type having a simple matrix configuration. In any case, a driver circuit for sending a signal for driving the liquid crystal to each wiring in the vertical and horizontal (X, Y) directions is provided around the display.

[0004] This driver circuit is usually constituted by a MOS integrated circuit (IC) of single crystal silicon. This I
C is provided with pad electrodes corresponding to the respective display electrodes, and a printed board is interposed between the two. First, the pad electrodes of the IC are connected to the printed board, and then the printed board is connected to the display. Was. This printed circuit board is an insulating substrate made of glass epoxy or paper epoxy or a substrate made of flexible plastic, and the occupied area must be equal to or larger than the display. Similarly, the volume had to be considerably increased.

[0005]

Such a conventional display has the following disadvantages due to the above-mentioned structure.

That is, the X direction of the matrix wiring, the Y direction
Since the same number of connections as the number of display electrodes or source (drain) wirings or gate wirings in the direction are made with the printed circuit board, there is a limit on the spacing between the connectable connection parts due to mounting technology. A high definition display could not be produced.

[0007] In addition to the display body, a printed board, an IC, and connection wiring are required, and the required area and volume are several times larger than the display body.

There are many connection points between the display main body and the printed circuit board and between the printed circuit board and the IC, and the connection parts are considerably heavy, so that an excessive force is applied to the connection parts and the reliability of the connection is low.

On the other hand, as a method of solving such a drawback, it has been proposed that, in a display, particularly a display device using an active element as a switching element, the active element and the peripheral circuit are constituted by TFTs on the same substrate. I have. However, according to this configuration, the aforementioned 3
Although the two disadvantages can be almost completely solved, another new problem has arisen.

In addition to the active elements, peripheral circuits
Because of T, the number of elements formed on the same substrate increases,
The manufacturing yield of the TFT has decreased. Accordingly, the production yield of the display has also been reduced.

The peripheral circuit portion has a very complicated device structure as compared with the device structure of the active device portion. Therefore, the circuit pattern becomes complicated, the manufacturing process technology becomes more sophisticated, and the cost increases. In addition, naturally, the number of multi-layer wirings is increased, and the number of process steps is increased and the manufacturing yield of the TFT is lowered.

Since a transistor constituting a peripheral circuit requires a high response speed, a polycrystalline semiconductor is usually used. Therefore, in order to polycrystallize the semiconductor layer,
High temperature processing was required, and an expensive quartz substrate or the like had to be used.

[0013]

SUMMARY OF THE INVENTION The present invention relates to the above-described 6 items.
The present invention relates to a liquid crystal display device which solves the problems described above in an appropriately balanced manner, has a low cost, and has a high production yield.

According to the present invention, a pixel matrix in which a plurality of TFTs are arranged in a matrix, a plurality of data lines connected to the pixel matrix, a plurality of scanning lines connected to the pixel matrix, An electro-optical device comprising: a first peripheral circuit connected to the data line; and a second peripheral circuit connected to the plurality of scanning lines, wherein the pixel matrix is connected to the TFT. An electro-optical device is provided, having a function of driving a pixel electrode, wherein the first peripheral circuit and the second peripheral circuit have a function other than driving the pixel electrode. .

According to the invention, a pixel matrix having a plurality of first TFTs arranged in a matrix, a plurality of data lines connected to the pixel matrix, and a plurality of data lines connected to the pixel matrix are provided. Scanning lines,
A first peripheral circuit having a second TFT connected to the plurality of data lines, and a first peripheral circuit connected to the plurality of scanning lines;
And a second peripheral circuit having a third TFT, wherein the pixel matrix has a function of driving a pixel electrode connected to the first TFT. The first peripheral circuit and the second peripheral circuit include:
An electro-optical device is provided, having a function other than driving the pixel electrode, wherein the first TFT and the second TFT are formed simultaneously in the same process.

According to the invention, a pixel matrix having a plurality of first TFTs arranged in a matrix, a plurality of data lines connected to the pixel matrix, and a plurality of data lines connected to the pixel matrix are provided. Scanning lines,
A first peripheral circuit having a second TFT connected to the plurality of data lines, and a first peripheral circuit connected to the plurality of scanning lines;
And a second peripheral circuit having a third TFT, wherein the pixel matrix has a function of driving a pixel electrode connected to the first TFT. The first peripheral circuit and the second peripheral circuit include:
The first peripheral circuit has a function other than driving the pixel electrode, and the first peripheral circuit includes a circuit having the second TFT.
C, and the second peripheral circuit includes the third T
A circuit having an FT and an IC, wherein the first TF
An electro-optical device is provided, wherein T and the second TFT are formed simultaneously in the same process.

That is, a first substrate on which a pixel matrix having a plurality of gate lines, a plurality of source (drain) lines and a thin film transistor is formed, a second substrate disposed opposite to the first substrate, and An electro-optical device including a liquid crystal composition held between a pair of substrates, wherein at least a part of a peripheral circuit connected to a matrix wiring in an X or Y direction formed on the first substrate. Is a thin film transistor having the same structure as the active element connected to the pixel, and the remaining peripheral circuits are constituted by semiconductor chips.

The connection between the IC and the substrate as the remaining non-TFT peripheral circuits and the substrate is performed by directly providing an IC chip on the substrate and using a COG method or an IC chip connected to each connection terminal.
This can be realized by a TAB method in which individual resin substrates are provided on a flexible organic resin substrate and the resin substrate and the display substrate are connected.

That is, the present invention does not use all the peripheral circuits of a liquid crystal display device as TFTs, but only a simple part of the element structure, only a functional part having a small number of elements, or a circuit part where a general-purpose IC is difficult to obtain. Only the portion where the cost of the IC is high, or only the portion where the cost of the IC is high, is made TFT, so that the production yield of the liquid crystal display device can be improved and the production cost can be reduced.

In addition, by forming a part of the peripheral circuit into a TFT, an external IC which has conventionally required a considerable number is required.
And the manufacturing cost can be reduced.

Furthermore, if the active element and the peripheral circuit are formed by the complementary process (CTFT) thin film transistor formed by the same process, the driving capability of the pixel is improved, the redundancy can be given to the peripheral circuit, and the margin can be provided. A certain liquid crystal display device could be driven.

When the entire peripheral circuit is formed as a TFT, the size of the display substrate must be increased in both the X direction and the Y direction, and the occupied area of the entire display device increases. Only a small size of the substrate is required, and the display device can be easily adjusted to the external dimensions of the computer or the device using the display device, and the display device occupies a small area and volume.

Parts where the element structure in the peripheral circuit is complicated,
For example, a high-level fabrication technology is required to turn the element structure that requires multilayer wiring or the part with the function of an amplifier into a TFT, but the part that is technically difficult by turning part of the TFT into a TFT. By using a conventional IC, a portion having a simple element structure or a simple function can be formed into a TFT, and a display device can be realized at low cost and high yield.

Further, by forming only a part of the TFTs, the number of thin film transistors in the peripheral circuit portion can be considerably reduced. If the functions of the peripheral circuits in the X and Y directions are the same, the number is almost half. Become. As described above, by reducing the number of elements to be TFTs, the production yield of the substrate can be improved, and a display device in which the area and volume of the substrate can be reduced can be realized at low cost.

Furthermore, by using a semi-amorphous semiconductor of a new concept instead of a conventionally used polycrystalline or amorphous semiconductor as a semiconductor layer used for a TFT, the semiconductor layer can be manufactured at a low temperature, and the carrier of A TFT with very high mobility and high response speed can be realized.

This semi-amorphous semiconductor is an LPC
It is obtained by performing a thermal crystallization treatment after forming a film by a VD method, a sputtering method, a PCVD method, or the like. The following description will be made by using a sputtering method as an example.

That is, when a single crystal silicon semiconductor is used as a target in the sputtering method and sputtering is performed with a mixed gas of hydrogen and argon, atomic silicon is separated from the target by sputtering (impact) of heavy atoms of argon, and the silicon is formed. While flying on a substrate having a surface, a cluster of tens to hundreds of thousands of atoms solidified at the same time leaves the target as a cluster and flies to the surface to be formed.

During the flight, hydrogen bonds with the dangling bonds of silicon in the outer periphery of the cluster, and forms a region having a relatively high order on the surface to be formed in the bonded state. In other words, on the film formation surface, there is high order
A state of a mixture of clusters having -H bonds and pure amorphous silicon is realized. This is heat-treated in a non-oxidizing gas at 450 ° C.
The Si-H bond reacts with another Si-H bond to form a Si-Si bond.

This bond pulls each other,
Highly ordered clusters tend to transfer phase to a higher ordered state, ie crystallization. However, between adjacent clusters, Si-Si bonded to each other pulls each cluster. As a result, the crystal has lattice distortion, and the crystal peak in laser Raman is measured shifted from the single crystal of 520 cm ⁻¹ to a lower wave number side.

Further, since the Si-Si bond between the clusters anchors (connects) each other, the energy band in each cluster can be electrically connected to each other via the anchoring portion. Therefore, it is fundamentally different from polycrystalline silicon in which a crystal grain boundary acts as a carrier barrier, and a carrier mobility of 10 to ²⁰⁰ cm ² / V Sec can be obtained.

That is, a semi-amorphous semiconductor based on such a definition can be expected to have a state in which although it has apparent crystallinity, there is substantially no crystal grain boundary electrically. Of course, the annealing temperature is 450 ° C.
When crystallization accompanied by crystal growth of 1000 ° C. or more is performed instead of the intermediate temperature annealing at 700 ° C., oxygen and the like in the film are bent out to the grain boundaries due to the crystal growth, and a barrier is formed. This is a material (polycrystal) having the same crystal and grain boundaries as a single crystal.

Further, when the degree of anchoring between clusters in the semiconductor is further increased, the carrier mobility is further increased. For this purpose, when the amount of oxygen in the film is reduced to 7 × 10 ¹⁹ cm ^−3, preferably 1 × 10 ¹⁹ cm ⁻³ or less,
Further, in addition to crystallization at a temperature lower than 600 ° C., high carrier mobility can be obtained.

[0033]

[Embodiment 1] In this embodiment, description will be made using a liquid crystal display device having an m × n circuit configuration as shown in FIG. That is, only the analog switch array circuit portion 1 among the peripheral circuit portions connected to the wiring in the X direction in FIG. 1 is formed into a TFT 5 in the same manner as the active element provided in the pixel 6, and the peripheral circuit connected to the Y direction wiring. As for the part, only the analog switch array circuit part 2 is converted to a TFT, and the other peripheral circuit parts are IC4.
And is connected to the substrate by the COG method. Where TF
The T-shaped peripheral circuit portion is formed as a CTFT (complementary configuration) similarly to the active element provided in the pixel.

FIG. 2 shows an actual arrangement of electrodes and the like corresponding to this circuit configuration. FIG. 2 shows only a portion corresponding to 2 × 2 for the sake of simplicity.

First, a method for manufacturing a TFT on a liquid crystal display device used in this embodiment will be described with reference to FIGS. FIG.
In (A), a silicon oxide film as a blocking layer 51 is formed on a glass 50 that can withstand a heat treatment at an inexpensive temperature of 700 ° C. or less, for example, about 600 ° C.
It is made to a thickness of 0 °. The process conditions were a 100% oxygen atmosphere, a film formation temperature of 15 ° C., an output of 400 to 800 W, and a pressure of 0.5 Pa. The film formation rate using quartz or single crystal silicon as a target was 30 to 100 ° / min.

On this, a silicon film was formed by LPCVD (low pressure gas phase), sputtering or plasma CVD. When formed by the reduced pressure gas phase method, the temperature is 1
450-550 ° C lower by 00-200 ° C, for example 530 ° C
CVD of disilane (Si ₂ H ₆ ) or trisilane (Si ₃ H ₈ )
The film was supplied to the apparatus to form a film. Reactor pressure is 30 ~ 300
Pa. The deposition rate was 50-250 ° / min.
Threshold voltage (Vt) between NTFT and PTFT
In order to control substantially the same as in h), boron may be added at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ cm ⁻³ during film formation using diborane.

When the sputtering method is used, the back pressure before the sputtering is set to 1 × 10 ⁻⁵ Pa or less, and single crystal silicon is used as a target in an atmosphere in which 20 to 80% of hydrogen is mixed with argon. For example, argon was 20% and hydrogen was 80%.
The film formation temperature was 150 ° C., the frequency was 13.56 MHz, the sputter output was 400 to 800 W, and the pressure was 0.5 Pa.

When a silicon film is formed by the plasma CVD method, the temperature is set to, for example, 300 ° C., and monosilane (SiH4) or disilane (Si ₂ H ₆ ) is used. These were introduced into a PCVD apparatus, and a high-frequency power of 13.56 MHz was applied to form a film.

The coatings formed by these methods are:
Oxygen is 5 × 10^{twenty one}cm^-3The following is preferred. This acid
If the element concentration is high, it is difficult to crystallize and the thermal annealing temperature
High or long thermal annealing times must be used.
If the amount is too small, the lamp is turned off by the backlight.
Current increases. Therefore 4 × 10¹⁹~ 4 × 10 ^{twenty one}
cm^-3Range. Hydrogen is 4 × 10²⁰cm^-3And silicon 4
× 10^{twenty two}cm^-3Was 1 atomic%. Also,
For promoting crystallization of source and drain
The oxygen concentration is 7 × 10¹⁹cm^-3Below, preferably 1 × 10¹⁹
cm^-3The following is the channel formation of the TFT that constitutes the pixel
Oxygen is ion-implanted only in the region 5 × 10²⁰~ 5 × 10
^{twenty one}cm^-3You may add so that it may become. At that time, peripheral circuits
Since the constituent TFTs are not irradiated with light,
Less carrier contamination and higher carrier mobility
Is effective for high frequency operation.
You.

Next, the amorphous silicon film is
After fabrication to a thickness of ~ 5000mm, for example 1500mm, 4
Medium-temperature heat treatment in a non-oxide atmosphere at a temperature of 50 to 700 ° C. for 12 to 70 hours, for example, 600 hours in a hydrogen atmosphere
It was kept at a temperature of ° C. Since a silicon oxide film having an amorphous structure is formed on the surface of the substrate under the silicon film, no specific nucleus is present in this heat treatment, and the whole is annealed uniformly. That is, it has an amorphous structure at the time of film formation, and hydrogen is simply mixed therein.

By the annealing, the silicon film shifts from an amorphous structure to a highly ordered state, and a part of the silicon film exhibits a crystalline state. In particular, a region having a relatively high order in a state after the formation of silicon is particularly likely to be crystallized to be in a crystalline state. However, since the silicon existing between these regions is bonded to each other, silicon mutually pulls each other. When measured by laser Raman spectroscopy, a single crystal silicon peak 522 is obtained.
A peak shifted to a lower frequency side than cm ⁻¹ is observed. Its apparent particle size is 50 to 5 when calculated from the half width.
Although it is a microcrystal with a size of 00Å, there are actually a large number of regions with high crystallinity and a cluster structure, and a semi-amorphous structure film in which each cluster is bonded to each other by silicon (anchoring). Could be formed.

As a result, the coating exhibits a state substantially free of grain boundaries (hereinafter referred to as GB). Carriers can easily move from one cluster to another through anchored locations, resulting in higher carrier mobility than so-called GB polycrystalline silicon. That is, hole mobility (μh) = 10 to ²⁰⁰ cm ² /
VSec, electron mobility (μe) = 15 to 300 cm ² / V
Sec is obtained.

On the other hand, when the film is polycrystallized by high-temperature annealing at 900 to 1200 ° C. instead of annealing at medium temperature as described above, segregation of impurities in the film occurs due to solid phase growth from nuclei. , GB contain many impurities such as oxygen, carbon, and nitrogen, and have a high mobility in the crystal. However, a barrier is formed in the GB to hinder the movement of carriers there. As a result, a mobility of 10 cm ² / Vsec or more cannot be easily obtained. That is, in this embodiment, a silicon semiconductor having a semi-amorphous or semi-crystalline structure is used for such a reason.

In FIG. 3A, a silicon film is subjected to photoetching using a first photomask, and a PTFT region 22 (channel width 20 μm) is placed on the right side of the drawing in the NTFT.
Region 13 was formed on the left side.

On this, a silicon oxide film was formed as a gate insulating film to a thickness of 500 to 2000 {for example, 1000}. This was made under the same conditions as those for forming the silicon oxide film as the blocking layer. During the film formation, a small amount of fluorine may be added to fix the sodium ions.

Thereafter, 1 to 5 × 10 ²¹ cm of phosphorus is placed on the upper side.
^-3 concentration silicon film or this silicon film and molybdenum (Mo), tungsten (W), MoSi2 or
A multilayer film with WSi2 was formed. This was patterned using a second photomask to obtain FIG. 3 (B). A gate electrode 55 for PTFT and a gate electrode 56 for NTFT were formed. For example, a channel length is 10 μm, a gate electrode is 0.2 μm of phosphorus silicon, and 0.3 μm of molybdenum is placed thereon.
It was formed to a thickness of μm. In FIG. 3C, a photoresist 57 is formed using a photomask, and a PTF is formed.
Boron is added to the source 59 for T
It was added by ion implantation at a dose of × 10 ¹⁵ cm ^-2 . Next, as shown in FIG. 3D, a photoresist 61 was formed using a photomask. Source 6 for NTFT
4. As the drain 62, phosphorus was added at a dose of 1 to 5 × 10 ¹⁵ cm ⁻² by ion implantation.

These operations were performed through the gate insulating film 54. However, in FIG. 3B, the gate electrodes 55, 56
May be used as a mask to remove silicon oxide on the silicon film, and then boron and phosphorus may be directly ion-implanted into the silicon film.

Next, annealing was performed again at 600 ° C. for 10 to 50 hours. The source 59 of the PTFT and the source 64 and the drain 62 of the drain 58NTFT were formed as P + and N + by activating impurities. Gate electrode 5
Channel formation regions 60 and 63 are formed below 5 and 56 as semi-amorphous semiconductors.

In this way, a C / TFT can be manufactured without applying a temperature to 700 ° C. or more in all steps, even though it is a self-aligned system. Therefore, it is not necessary to use an expensive substrate such as quartz as a substrate material, and the process is very suitable for a liquid crystal display device having a large pixel.

In this embodiment, the thermal annealing is performed as shown in FIG.
(D) was performed twice. However, the annealing in FIG. 3A may be omitted depending on the desired characteristics, and both may be replaced by the annealing in FIG. 3D to shorten the manufacturing time. In FIG. 4A, a silicon oxide film is formed on the interlayer insulator 65 by the above-described sputtering method. This silicon oxide film may be formed by an LPCVD method, a photo CVD method, or a normal pressure CVD method. For example, it is formed to a thickness of 0.2 to 0.6 μm, and thereafter,
A window 66 for an electrode was formed using a photomask. Further, aluminum is formed on the entire surface by sputtering, and leads 71 and 72 and contacts 67 and 68 are formed using a photomask. Then, the surface is flattened with an organic resin 69 for flattening, for example, a translucent polyimide resin. Forming
The electrode drilling was performed again using a photomask.

As shown in FIG. 4B, in order to connect the two TFTs to a complementary structure and connect the output terminals thereof to the electrodes of one pixel of the liquid crystal device as transparent electrodes, ITO (indium metal) is formed by sputtering. A tin oxide film). It is etched using a photomask and the electrodes 7
0 was configured. This ITO film was formed at room temperature to 150 ° C., and was achieved by oxygen at 200 to 400 ° C. or annealing in air. Thus, PTFT 22 and NTF
The same glass substrate 50 as T13 and the electrode 70 of the transparent conductive film
Made above. The electrical characteristics of the obtained TFT are PTF
At T, the mobility is 20 (cm ² / Vs), Vth is -5.9 (V),
The mobility of NTFT is 40 (cm ² / Vs) and Vth is 5.0 (V).
Met.

FIG. 2 shows an arrangement of electrodes and the like in a pixel portion of the liquid crystal display device. NTFT 13 is connected to the first scanning line 1
5 at the intersection of the data line 21 and the first scanning line 15
NTFTs for other pixels are similarly provided at the intersections between the data lines 14 and the data lines 14. On the other hand, PTFT is the second scanning line 1
8 and the data line 21. Also,
An NTFT for another pixel is provided at the intersection of the adjacent first scanning line 16 and data line 21. A matrix configuration using such a C / TFT is provided. The NTFT 13 is connected to the first scanning line 15 via a contact at the input end of the drain 64, and the gate 56 is connected to the data line 21 on which a multilayer wiring is formed.
The output terminal of the source 62 is connected to the pixel electrode 1 through a contact.
7 is connected.

On the other hand, the PTFT 22 has an input terminal of the drain 58 connected to the second scanning line 18 through a contact,
The gate 55 is connected to the data line 21 and the output terminal of the source 59 is connected to the pixel electrode 17 via a contact in the same manner as the NTFT. Thus, the pixel 23 made of the transparent conductive film and the C / TF are interposed (inside) between the pair of scanning lines 15 and 18.
T constituted one pixel. By repeating such a structure left, right, up and down, a 2 × 2 matrix is enlarged to 640 × 480, 1280 × 960.
Large-pixel liquid crystal display device.

As described above, a CMOS configuration is provided in which the NTFT 13 and the PTFT 22 manufactured by the same process as the switching element are provided.

As described above, one of the substrates is completed.
The other substrate is bonded by a conventional method, and STN liquid crystal is injected between the substrates. Next, as the remaining peripheral circuits, I
Use C4. This IC 4 is connected to each of the X-direction wiring and the Y-direction wiring of the substrate by COG.
This IC 4 is only connected to connection leads for supplying power and data from the outside, and there is no FPC for connection on one side of the board. The number is considerably reduced and reliability is improved. Thus, a liquid crystal display device was completed.

In this embodiment, only the analog switch array portion 1 of the peripheral circuits on the X direction side is connected to the analog switch array portion 2 of the peripheral circuits on the Y direction side only.
FT and C / TF in the same process as the switching element
Although the peripheral circuit portion is configured by IC4, the configuration is not particularly limited to this configuration. Considering the yield at the time of forming the TFT, the problem of the process technology at the time of forming the TFT, and the like, Only the portion that is easy to make into a TFT may be made into a TFT.

In this embodiment, since a semi-amorphous semiconductor is used as the semiconductor film, the mobility is at least ten times higher than that of a TFT using a non-single-crystal semiconductor. Therefore, it can be used satisfactorily even for TFTs in peripheral circuits that require a high response speed, and is manufactured by the same process as an active element without the need to specially crystallize TFTs in a peripheral circuit portion as in the related art. I was able to.

Also, since the active element connected to the liquid crystal pixel is of a C / TFT configuration, the operating margin is expanded, the pixel potential does not fluctuate, and a constant display level can be ensured. However, there is an advantage that even if the defect is not good, a noticeable defect is not displayed.

[0059]

Embodiment 2 FIG. 5 shows a schematic external view of a liquid crystal display device of this embodiment. The basic circuit and the like are exactly the same as in the first embodiment. In FIG. 5, a portion of the peripheral circuit connected to the wiring in the Y direction, which is configured by the IC 4, has the IC formed directly on the substrate by the COG method. The IC 4 is provided separately on the upper and lower portions of the substrate.

In this case, in the connection between the pad electrode of the IC 4 and the Y-directional wiring, the interval can be narrowed as compared with the case where the IC is formed only on one side. Therefore, it has a feature that a higher definition display pixel can be designed. Further, since the IC is provided on the substrate, the volume is hardly increased, and a thinner liquid crystal display device can be provided.

In the above embodiment, the TFTs of the active elements have a CMOS configuration. However, the present invention is not limited to this configuration. The TFTs may be composed of only NTFTs and PTFTs. The configuration increases the number of elements.

The position where the TFT is formed on the substrate is indicated by X
A TFT is formed not only on one side connected to the wiring in the direction or the Y direction, but also on the other side, and the TFTs are alternately formed.
By connecting T, the density of the TFT is reduced by half, thereby improving the manufacturing yield of the TFT.

[0063]

According to the present invention, it is no longer impossible to increase the definition of a liquid crystal display due to restrictions on external connection technology.
Further, unnecessary connection between the wiring in the X direction or the wiring in the Y direction and the external peripheral circuit could be minimized, so that the reliability at the connection portion was improved.

In order to make only some of the peripheral circuits into TFTs,
The exclusive area of the display board itself can be reduced,
In addition, the substrate can be freely designed to the required dimensions and shape. In addition, it is possible to avoid a problem in manufacturing a TFT and to make only a portion having a high manufacturing yield into a TFT. Therefore, the manufacturing cost could be reduced.

Since a semi-amorphous semiconductor is used as the semiconductor film used for the TFT, a response speed which can be sufficiently used for peripheral circuits can be obtained. A TFT for a circuit could be formed at the same time.

The present invention clarifies the threshold value by connecting complementary TFTs to each pixel in a matrix, increases the switching speed, and expands the operation margin.
Even if there are some defective TFTs, compensation can be made to some extent. The number of photomasks required for fabrication is NT
It is only increased twice as compared with the conventional example using only FT.
Since the mobility of the carrier is ten times or more as large as that in the case of using amorphous silicon, the size of the TFT can be reduced, and even if two TFTs are provided in one pixel, the aperture ratio hardly decreases. It has many features.

Therefore, as compared with the conventional active TFT liquid crystal device using only NTFT, it is possible to achieve a several-stage production yield and a vividness of the screen.

[Brief description of the drawings]

FIG. 1 is a diagram showing a liquid crystal display device having an m × n circuit configuration.

FIG. 2 is a diagram illustrating an arrangement of pixel portions of a liquid crystal display device.

FIG. 3 is a diagram schematically illustrating a manufacturing process of a TFT.

FIG. 4 is a diagram schematically illustrating a manufacturing process of a TFT.

FIG. 5 is a diagram showing another embodiment.

[Explanation of symbols]

 1, 2, ... Peripheral circuit 4 ... IC 5 ... Peripheral circuit made into TFT 6 ... Pixel 13 NTFT 22 PTFT

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G09G 3/36 G09G 3/36 H01L 21/203 H01L 21/203 S 29/786 29/78 612A

Claims (3)

[Claims] A plurality of TFTs arranged in a matrix; a plurality of data lines connected to the pixel matrix; a plurality of scanning lines connected to the pixel matrix; and a plurality of data lines. An electro-optical device comprising: a first peripheral circuit connected to the plurality of scanning lines; and a second peripheral circuit connected to the plurality of scanning lines, wherein the pixel matrix includes a pixel electrode connected to the TFT. An electro-optical device having a driving function, wherein the first peripheral circuit and the second peripheral circuit have a function other than driving the pixel electrode. 2. A plurality of first Ts arranged in a matrix.
A pixel matrix having an FT, a plurality of data lines connected to the pixel matrix, a plurality of scanning lines connected to the pixel matrix, and a second TFT connected to the plurality of data lines, the second TFT having 1. An electro-optical device, comprising: a first peripheral circuit; and a second peripheral circuit having a third TFT connected to the plurality of scanning lines, wherein the pixel matrix is connected to the first TFT. The first peripheral circuit and the second peripheral circuit have a function other than driving the pixel electrode, and the first TFT and the first TFT An electro-optical device, wherein the second TFT is formed simultaneously in the same process. 3. A plurality of first Ts arranged in a matrix.
A pixel matrix having an FT, a plurality of data lines connected to the pixel matrix, a plurality of scanning lines connected to the pixel matrix, and a second TFT connected to the plurality of data lines, the second TFT having 1. An electro-optical device, comprising: a first peripheral circuit; and a second peripheral circuit having a third TFT connected to the plurality of scanning lines, wherein the pixel matrix is connected to the first TFT. The first peripheral circuit and the second peripheral circuit have a function other than driving the pixel electrode, and the first peripheral circuit has a function of driving the pixel electrode. Has a circuit and an IC having the second TFT, the second peripheral circuit has a circuit and an IC having the third TFT, and has the first TFT and the first TFT. 2 TFTs are the same process. In electro-optical device characterized in that it is formed at the same time.