JP2003029299A - Substrate device and manufacturing method thereof, electro-optical device, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of a substrate device suitably used for a liquid crystal device with a built-in drive circuit including a transistor for pixel switching and a drive circuit including the transistor, and to provide high quality. Is displayed. An image display area on a substrate includes a pixel electrode and a first transistor connected to the pixel electrode, and a peripheral area on the substrate includes a wiring for driving the first transistor and a wiring connected to the wiring. And a second transistor forming a part of the driving circuit. A first gate insulating film constituting the first transistor is formed from an oxide film into which nitrogen has not been introduced. A second gate insulating film forming the second transistor is formed from an oxynitride film into which nitrogen has been introduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-optical device such as a liquid crystal device having a built-in drive circuit, which has a pixel switching transistor in an image display region and a drive circuit including the transistor in a peripheral region. In the device, a substrate device preferably used as an element array substrate and the like, a method of manufacturing such a substrate device, an electro-optical device such as a liquid crystal device including such a substrate device, and the electro-optical device are provided. It belongs to the technical field of various electronic devices such as a projection display device.

[0002]

2. Description of the Related Art A substrate device of this type is provided with a semiconductor film such as a polysilicon film including a source region, a drain region and a channel region, or a semiconductor film such as amorphous silicon on a substrate such as a quartz substrate. On the surface of this semiconductor film, a thermal oxide film by dry oxidation or wet oxidation, an HTO film,
A gate insulating film is formed from the TEOS film and the plasma oxide film. Further, by forming a gate electrode film on the gate insulating film, a thin film transistor (hereinafter appropriately referred to as TFT (Thin Film Transistor)) is constructed on the substrate. In this case, the TFT is used as a pixel switching element by being built in each pixel in the image display area in the above-described substrate device with a built-in drive circuit. Further, it is used as a part of the built-in drive circuit of the substrate device by being built in the peripheral region located outside the image display region.

Such a substrate device having a built-in driving circuit in which TFTs are formed in both the image display region and the peripheral region is widely used in various electro-optical devices such as a liquid crystal device of a TFT active matrix driving system. Has been.

[0004]

In this type of substrate device, there is a general demand for maintaining good transistor characteristics for a long period of time and enhancing the quality of a display image.

However, according to the research conducted by the inventors of the present application, in the case of the above-described substrate device having a built-in drive circuit,
According to the study by the inventors of the present application, in the case of the above-described substrate device with a built-in drive circuit, maintaining the transistor characteristics in terms of time has become a problem. In particular, it has been found that the deterioration of the P-channel type TFT that constitutes the drive circuit leads to the deterioration of the image quality such as the decrease of the contrast ratio and the brightness, and the life of the entire device is shortened. For example, the threshold voltage of the TFT constituting the drive circuit increases and the TFT does not function as a switching element at a normal drive voltage, or the off current (ie, leak current) of the TFT increases and the prescribed duty ratio cannot be dealt with. . As a result, even if the TFTs in the image display area formed by the same manufacturing process on the same substrate are operating normally, the deterioration of the TFTs in the drive circuit over time causes the entire device to become defective. There is a problem.

On the other hand, in the research conducted by the present inventors,
We have also examined the use of nitrogen doping technology for gate oxide films in semiconductor manufacturing technology to extend the life of TFTs.
It has been confirmed that variations in transistor characteristics and a decrease in carrier mobility in the pixel switching TFT become apparent, resulting in significant display unevenness and flickering.
After all, if this nitrogen doping technique is simply applied, then it becomes very difficult to display a high-quality image.

The present invention has been made in view of the above-mentioned problems, and provides a substrate device having a long life and capable of displaying a high-quality image for a long period of time, and a method of manufacturing the same. An object of the present invention is to provide an electro-optical device including such a substrate device and an electronic device including the electro-optical device.

[0008]

In order to solve the above-mentioned problems, the substrate device of the present invention includes a substrate, a pixel electrode in the image display region on the substrate, and a first electrode connected to the pixel electrode.
A second region which includes a transistor and which forms a part of a wiring for driving the first transistor and a driving circuit connected to the wiring in a peripheral region located around the image display region on the substrate; A first gate insulating film forming a first transistor, the first gate insulating film comprising an oxide film into which nitrogen is not introduced;
The second gate insulating film forming the transistor is made of an oxynitride film into which nitrogen is introduced.

According to the substrate device of the present invention, the wiring such as the scanning line and the data line is formed by the driving circuit such as the scanning line driving circuit and the data line driving circuit which is configured to include the second transistor in the peripheral region. The first transistor arranged in the image display area is driven via. Further, the pixel electrodes are drive-controlled or switching-controlled by the first transistor, so that active matrix driving is performed in the image display region.

Here, in particular, since the first gate insulating film forming the first transistor is made of an oxide film into which nitrogen is not introduced, variations in transistor characteristics due to introduction of nitrogen into the gate insulating film and carrier mobility. There is no display unevenness or flicker due to deterioration. Then, since nitrogen is not introduced into the gate insulating film, the life of the transistor is not extended as compared with the case where nitrogen is introduced, but as long as it is used as a pixel switching transistor which does not generally regulate the device life, It is theorized that even if the life of the transistor itself is not extended, it has little or no effect on the life of the device. That is, the first
By forming the gate insulating film from an oxide film, there are practically no problems with regard to device life.

On the other hand, since the second gate insulating film which constitutes the second transistor of the drive circuit which generally controls the life of the device is composed of an oxynitride film into which nitrogen is introduced, the gate insulating film is an oxide film into which nitrogen is not introduced. Since the life of the transistor is remarkably extended as compared with the case of, the life of the entire device can be extended very efficiently. That is, it is possible to extend the life of the device as it is by the extension of the life of the second transistor. Then, unlike the case of the first transistor for pixel switching, in the case of the second transistor of the drive circuit, which is not subject to the constraint of matching the pixel pitch and not narrowing the aperture area of each pixel, the channel width and the channel It is possible to make slight modifications or changes to the transistor structure itself, such as the length, so that variations in transistor characteristics and deterioration of carrier mobility due to the introduction of nitrogen into the gate insulating film adversely affect the operation of the drive circuit. Can be effectively prevented.

As a result, when an electro-optical device such as a liquid crystal device is constructed using the substrate device of the present invention, the first gate insulating film in the image display area is made of an oxide film and the second gate insulating film in the peripheral area is formed. With the unique structure of the present invention, which is composed of an oxynitride film, the life of the device can be remarkably extended, and at the same time, high-quality image display can be maintained for a long time.

In one aspect of the substrate device of the present invention, the second
The transistor is a P-channel TFT or CMOS (Com
Complementary MOS) type TFT.

According to this aspect, the second transistor is P
It comprises a channel type TFT. Here, according to the study by the present inventors, it has been found that the life of the P-channel TFT is basically shorter than that of the N-channel TFT. Therefore, in the P-channel TFT, the second
By forming the gate insulating film from an oxynitride film and extending the life of the P-channel TFT, a great effect can be obtained in extending the life of the device. In particular, when at least a part of the driving circuit is composed of a CMOS type TFT, an N-channel type T excellent in basic performance such as carrier mobility and device life.
It cannot be composed of FT only, and is a P-channel TF
Since there is no choice but to build T, the configuration like this embodiment is very excellent in practical use.

In another aspect of the substrate device of the present invention, the first transistor is an N-channel type.

According to this aspect, by using the N-channel TFT which is more excellent in basic performance such as carrier mobility and device life for pixel switching, high quality image display can be made possible, and moreover, The life of the entire device including the drive circuit can be extended.

In another aspect of the substrate device of the present invention, the semiconductor layers forming the first and second transistors are made of low temperature or high temperature polysilicon or amorphous silicon. Although a polysilicon TFT, a high-temperature polysilicon TFT, or an amorphous silicon TFT is constructed, by forming the second gate insulating film in the drive circuit from an oxynitride film, the whole substrate device including the polysilicon TFT or the amorphous silicon TFT Can have a long life.

In another aspect of the substrate device of the present invention, the second transistor is provided in the drive circuit as a switching element that is turned on / off when the gate voltage exceeds a threshold value.

According to this aspect, the second transistor is
Since it is provided as a switching element that is turned on and off when the gate voltage exceeds a threshold value, that is, because it is provided as an extremely simple operation as a transistor, it is caused by forming the gate insulating film from an oxynitride film. In another aspect of the substrate device of the present invention, in which variations in transistor characteristics and deterioration of carrier mobility can be prevented from being exposed to the surface as an adverse effect, the second transistor is formed on another substrate, and then the periphery of the second transistor is reduced. Pasted in the area.

According to this aspect, after forming the second transistor having the oxynitride film as the gate insulating film on the other substrate, the second transistor can be attached to the peripheral region, so that the device structure and the manufacturing process can be simplified. Can be achieved.

In order to solve the above problems, the first method of manufacturing a substrate device according to the present invention is directed to the above-described substrate device of the present invention (however,
(Including various aspects thereof), a method for manufacturing a substrate device, wherein a semiconductor having a first semiconductor layer forming the first transistor and a second semiconductor layer forming the second transistor is formed on the substrate. A layer forming step, an oxynitride film forming step of forming an oxynitride film on the first and second semiconductor layers, and masking a portion of the formed oxynitride film formed on the second semiconductor layer. Meanwhile, a removal step of selectively removing a portion of the formed oxynitride film formed on the first semiconductor layer, and the oxide film on the first semiconductor layer from which the oxynitride film is removed. The method includes a step of forming an oxide film and a step of forming a gate electrode on each of the oxynitride film and the oxide film thus formed.

According to the first manufacturing method of the present invention, the oxynitride film is formed on the first and second semiconductor layers after they are formed. Then, while masking the portion of the oxynitride film formed on the second semiconductor layer, the portion formed on the first semiconductor layer is selectively removed. Therefore, the oxynitride film is formed on the second semiconductor layer. Further, since the oxide film is formed on the first semiconductor layer from which the oxynitride film is removed, the oxide film is formed on the first semiconductor layer.
After that, since the gate electrodes are formed on the oxynitride film and the oxide film, respectively, the substrate device of the present invention described above can be manufactured relatively easily.

In order to solve the above problems, a second method of manufacturing a substrate device according to the present invention is directed to the above-described substrate device of the present invention (however,
(Including various aspects thereof), a method for manufacturing a substrate device, wherein a semiconductor having a first semiconductor layer forming the first transistor and a second semiconductor layer forming the second transistor is formed on the substrate. A layer forming step, a nitride film forming step of selectively forming a nitride film on the first semiconductor layer while masking the second semiconductor layer, and an oxynitride on the second semiconductor layer on which the nitride film is not formed. An oxynitride film forming step of selectively forming a film, and a removing step of removing the nitride film,
An oxide film forming step of forming an oxide film on the first semiconductor layer from which the nitride film is removed, and a gate electrode forming step of forming a gate electrode on each of the formed oxynitride film and oxide film are included. .

According to the second manufacturing method of the present invention, after forming the first and second semiconductor layers, a nitride film is formed on the first semiconductor layer while masking the second semiconductor layer among them. Then, this time, using the nitride film as a mask, an oxynitride film is formed on the second semiconductor layer on which the nitride film is not formed.
Therefore, the oxynitride film is formed on the second semiconductor layer. Further, on the first semiconductor layer from which the nitride film is removed,
Since the oxide film is formed, the oxide film is formed on the first semiconductor layer. After that, since the gate electrodes are formed on the oxynitride film and the oxide film, respectively, the substrate device of the present invention described above can be manufactured relatively easily.

In order to solve the above problems, the third method of manufacturing a substrate device according to the present invention is directed to the above-described substrate device of the present invention (however,
(Including various aspects thereof), a method for manufacturing a substrate device, wherein a semiconductor having a first semiconductor layer forming the first transistor and a second semiconductor layer forming the second transistor is formed on the substrate. A layer forming step, an oxide film forming step of forming an oxide film on the first and second semiconductor layers,
An oxynitride film forming step of selectively forming an oxynitride film on the oxide film formed on the second semiconductor layer while masking the oxide film formed on the first semiconductor layer with a nitride film; And a gate electrode forming step of forming gate electrodes on the oxynitride film and the oxide film, respectively, after the film is removed.

According to the third manufacturing method of the present invention, after forming the first and second semiconductor layers, an oxide film is formed on both of them. Then, among these, the oxide film formed on the first semiconductor layer is masked by the nitride film, and the oxynitride film is further formed on the oxide film formed on the second semiconductor layer. At this time, for example, nitrogen may be injected into the oxide film, an oxynitride film may be stacked on the oxide film, or N may be formed.
Nitrogen may be introduced into the oxide film by annealing with ₂ O or NONH ₂ gas. Therefore, the oxynitride film is formed on the second semiconductor layer. Further, if the nitride film is removed after the oxynitride film is formed,
This means that the oxide film is formed instead of the oxynitride film. After that, since the gate electrodes are formed on the oxynitride film and the oxide film, respectively, the substrate device of the present invention described above can be manufactured relatively easily.

In order to solve the above problems, a fourth manufacturing method is a method for manufacturing a substrate device of the present invention described above (however, including various aspects thereof), in which the above-mentioned substrate is formed on the substrate. A semiconductor layer forming step of forming a first semiconductor layer forming a first transistor and a second semiconductor layer forming the second transistor; and the first semiconductor layer while masking the second semiconductor layer with a nitride film or a resist. An oxynitride film forming step of selectively forming an oxynitride film thereon; and an oxynitride film forming step of selectively forming an oxynitride film on the second semiconductor layer after removing the nitride film. And forming a gate electrode on the oxynitride film and the oxide film, respectively.

According to the fourth manufacturing method of the present invention, after forming the first and second semiconductor layers, an oxide film is formed on the first semiconductor layer while masking the second semiconductor layer with a nitride film or a resist. . Then, after the oxide film is formed, the nitride film is removed, and an oxynitride film is further formed on the second semiconductor layer. Therefore, the oxynitride film is formed on the second semiconductor layer, and the oxide film, not the oxynitride film, is formed on the first semiconductor layer. After that, since the gate electrodes are formed on the oxynitride film and the oxide film, respectively, the substrate device of the present invention described above can be manufactured relatively easily.

In one aspect of the first to fourth manufacturing methods of the present invention, the oxynitride film forming step includes a step of oxidizing in an atmosphere containing nitrogen.

According to this aspect, the oxynitride film forming step can be performed relatively easily by annealing in an atmosphere of a gas containing nitrogen atoms using an existing furnace (diffusion furnace) or the like.

In this aspect, the oxynitride film forming step is performed with N
_It may include a step of annealing in an atmosphere containing at least one of a ₂ O (dinitrogen monoxide) gas, a NO (mononitrogen monoxide) gas, and an NH ₄ (ammonia) gas.

If manufactured in this way, the oxynitride film forming step can be performed relatively easily and inexpensively.

In another aspect of the first to fourth manufacturing methods of the present invention, the oxynitride film forming step is any one of vertical or horizontal diffusion furnace, nitriding using plasma, lamp annealing or ion implantation. Including steps.

According to this aspect, existing plasma technology,
By lamp annealing or ion implantation, the oxynitride film forming step can be performed relatively easily.

In another aspect of the first to fourth manufacturing methods of the present invention, the oxynitride film forming step includes a step of doping nitrogen after forming an oxide film.

According to this aspect, since the oxynitride film forming step can be performed by once forming the oxide film and then doping or injecting nitrogen, the oxide film forming step and the oxynitride film forming step are performed in phase with each other. It is also possible to carry out continuously before and after.

Another aspect of the first to fourth manufacturing methods of the present invention further includes a thinning step of thinning the oxide film or the oxynitride film formed on the first and second semiconductor layers.

According to this aspect, by thinning the oxide film or the oxynitride film once formed on the second semiconductor layer, the oxynitride film having a desired film thickness can be formed relatively easily.

In order to solve the above problems, the electronic equipment of the present invention comprises the above-described electro-optical device of the present invention (however, including various aspects thereof).

According to the electronic apparatus of the present invention, since it is equipped with the electro-optical device of the present invention described above, various types of projection type display devices, etc., which have a long life and can display a high-quality image for a long period of time. Electronic devices can be realized.

The operation and other advantages of the present invention will be apparent from the embodiments described below.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment of Substrate Device) First, a manufacturing method and a structure of a substrate device of the first embodiment will be described with reference to FIGS. 1 and 2 are process diagrams sequentially showing the manufacturing method of the first embodiment, in which a pixel switching TFT (left half surface in the drawings) provided in a pixel portion is provided.
Also, regarding the TFT (right half surface in the drawing) that constitutes the peripheral drive circuit, the cross-sectional structure in the vicinity of the TFT for each process is shown. FIG. 3 is a characteristic diagram showing the secondary strength of oxygen and silicon and the nitrogen concentration in the portion from the gate insulating film to the semiconductor layer formed in step (2) with respect to the depth from the surface of the gate insulating film. is there. FIG. 4 is a characteristic diagram showing the deviation amount Vdd (V) from the initial value of the threshold value Vth with respect to the operating time in a plurality of examples in which the introduction amount of nitrogen atoms is changed and a comparative example in which the nitrogen atom is not introduced. .

In step (1) of FIG. 1, the quartz substrate 1 is used.
0 and an oxide film formed on the quartz substrate 10 are prepared,
After the polysilicon film is formed thereon, the semiconductor layer 1a having a predetermined pattern including the source region, the channel region and the drain region of the TFT is formed in each of the pixel portion and the peripheral drive circuit portion by photolithography and etching. It Such a semiconductor layer 1a may be a low temperature polysilicon film, a high temperature polysilicon film, or amorphous silicon. Further, instead of the quartz substrate 10, a plastic substrate, a glass substrate or the like may be used.

Next, in step (2), a thermally oxidized silicon film is first formed on the surface of the semiconductor layer 1a by dry oxidation or wet oxidation, and then nitrogen atoms are added in a furnace (diffusion furnace). By annealing in an atmosphere of a gas containing nitrogen, a gate insulating film 2b into which nitrogen atoms are introduced is formed. As such a gas, nitrogen gas such as N ₂ O gas, NO gas, and NH ₄ gas is used. Simultaneously with the formation of the gate insulating film 2b, the same film 2b 'as the gate insulating film 2b is formed in the pixel portion on the same substrate.

By introducing nitrogen atoms in this way, for example, nitrogen atoms have a concentration distribution as shown in the characteristic diagram of FIG.

Then, in step (3), the gate insulating film 2 is formed.
With the resist b being masked on b, the etchant 50 is etched by dry etching such as reactive etching using a reactive gas, dry etching such as reactive ion beam etching, or etching combined with wet etching.
1, the film 2b ′ identical to the gate insulating film 2b is removed in the pixel portion. As a result, in the pixel portion, the semiconductor layer 1
a is exposed again. Then, in step (4), if the resist 601 is peeled and removed, a state in which the gate insulating film 2b made of an oxynitride film into which nitrogen is introduced is formed only in the peripheral drive circuit portion.

Next, in step (5), a thermally oxidized silicon film is formed on the surface of the semiconductor layer 1a as a gate insulating film 2a in the pixel portion by dry oxidation, wet oxidation, or an HTO film. Simultaneously with the formation of the gate insulating film 2a, the same film 2a 'as the gate insulating film 2a is formed in the peripheral circuit portion on the same substrate.

Next, in step (6), the gate insulating film 2a in the pixel portion is masked with the resist 602, and dry etching such as reactive etching using a reactive gas or reactive ion beam etching is performed. By etching combined with wet etching, the same film 2a ′ as the gate insulating film 2a is obtained from the etchant 502.
Are removed in the peripheral drive circuit section. Then, in step (7) of FIG. 2, the resist 602 is peeled and removed, so that a state in which the gate insulating film 2a made of an oxide film into which nitrogen is not introduced is formed only in the pixel portion is obtained. Moreover, in the peripheral drive circuit section, as in the step (4),
The state in which the gate insulating film 2b made of an oxynitride film into which nitrogen is introduced is formed is maintained.

Next, in step (8), gate electrodes 3a and 3b made of a conductive polysilicon film or the like are formed on the gate insulating films 2a and 2b, respectively. Further, in step (9), contact holes for connecting the source electrode and the drain electrode are formed in the gate insulating films 2a and 2b by dry etching, wet etching, or a combination of both. Then, through these contact holes, in the pixel portion as shown by the broken line in the figure, Al
The end of the data line 6a made of (aluminum) or the like and I
The ends of the pixel electrode 9a made of TO (indium tin oxide) or the like are connected as a source electrode and a drain electrode. Before or after this, or in parallel with this, in the peripheral drive circuit section, the wirings 6b and 6c made of Al or the like are connected as a source electrode and a drain electrode.

Through the above steps (1) to (9), the substrate 1
TFTs are respectively constructed in the pixel portion and the peripheral drive circuit portion on the 0.

As described above, in the peripheral drive circuit portion, the introduction of nitrogen into the gate insulating film 2b causes the trapping of positive holes and positive charges at the interface, which is the main cause of the deviation of the threshold value of the TFT, and the increase of the interface level. To reduce. Then, by introducing nitrogen, the nitride film bonding is mixed and the moisture resistance is improved. As a result, the amount of water entering the semiconductor layer 1a can be reduced, the generation of Si—H bonds and S—OH bonds can be reduced, and the generation of positive charges and the increase of interface states can be reduced. In addition, the introduction of nitrogen atoms allows the nitrogen atoms to enter the atom-to-atom network in this region, whereby the strain at the interface can be relaxed and the portion where the bond is weak can be reinforced. Here, the magnitude relation regarding the stability of the binding energy is as follows.

Si—O bond energy (4.8 eV)> Si—N bond energy (3.5 eV)> Si—H bond energy (3.2 eV)> Si—Si bond energy (2.0 eV) Among them, the relatively high Si—O bond energy is considered to be small due to the distortion of the bond state.
The presence of nitrogen atoms can reduce Si—Si bonds, distorted Si—O—Si bonds, Si—H bonds, and Si—OH bonds. It is possible to prevent formation of interface states and trap centers in the oxide film due to hot carriers.

Incidentally, regarding the moisture resistance, an oxide film (SiO 2
_TwoNitride film (Si_ThreeN _FourExcellent)
It However, in the case of the substrate device as in the present invention,
If the gate insulating film is composed of the nitride film,
The characteristics of the switch are that the pool Frenkel current flows.
The characteristics cannot be used as a switching element.
Furthermore, if the gate insulating film is composed of a nitride film,
A contact hole for making contact with the body layer has already been
It is extremely difficult to open holes with existing etching technology.
turn into.

Therefore, in the peripheral drive circuit portion, the gate insulating film 2b is formed not by a nitride film (silicon nitride film) but by a silicon oxide film, and nitrogen atoms are introduced into the silicon oxide film to form the gate insulating film 2b. The IV characteristic of the TFT can be the IV characteristic in which an FN current flows, similarly to a TFT using a normal oxide film as a gate insulating film, and can be suitably used as a switching element. Further, when the contact hole is opened in the step (9) of FIG. 1, it is not difficult to etch like a nitride film, and the existing dry etching technique or wet etching technique is used to make contact relatively easily and with high precision. The hole can be opened.

As described above, according to this embodiment, in the peripheral circuit portion, the gate insulating film 2b is made of an oxynitride film into which nitrogen is introduced, and therefore, compared with the gate insulating film 2a made of an oxide film in which nitrogen is not introduced. Since the life of the TFT is remarkably extended, it is possible to extend the life of the entire device very efficiently. That is, for example, in the order of several thousand hours to ten thousand thousands hours or tens of thousands hours, it is possible to extend the device life of the entire substrate device as it is by the extension of the life of the TFT in the peripheral drive circuit section. In addition, by slightly modifying or changing the transistor structure itself such as the channel width and the channel length, variations in transistor characteristics and deterioration in carrier mobility due to introduction of nitrogen into the gate insulating film 2b may occur. It is possible to prevent the operation from being adversely affected.

The effect of the same tendency has been confirmed even by adding a small amount of nitrogen atoms. Further, although it is technically possible to introduce nitrogen up to about 20% by weight with relative ease, further effects can be expected by increasing the nitrogen concentration.

On the other hand, according to the present embodiment, in the pixel portion, since nitrogen is not introduced into the gate insulating film 2a, the gate insulating film 2a is made of an oxide film. Therefore, display unevenness and flickering due to variations in transistor characteristics due to introduction of nitrogen into the gate insulating film and deterioration of carrier mobility do not occur. Then, since nitrogen is not introduced into the gate insulating film 2a, the gate insulating film 2 containing nitrogen is introduced.
Although the life of the TFT does not extend as compared with b, since it is used as a pixel switching TFT that does not regulate the life of the device, practical problems of the device life of the whole substrate device do not occur.

Here, the deviation amount Vdd (V) from the initial value of the threshold value Vth with respect to the operating time in a plurality of examples in which the introduction amount of nitrogen atoms to the gate insulating film is changed and a comparative example in which nitrogen atoms are not introduced is shown. 4 shows. In Figure 4,
Vdd for each example in which the temperature inside the furnace was 1000 ° C. or 1150 ° C., the N ₂ O gas concentration in the atmosphere inside the furnace was 20 flow% or 5 flow%, and the diffusion time was 20 minutes or 10 minutes. Comparative example (Referenc
The voltage Vdd for e) is shown.

As shown as a comparative example in FIG. 4, in the case of the conventional substrate device using the dry oxide film as the gate insulating film, when the normal operation is continued, the threshold voltage of the gate voltage for turning on the TFT is increased. The Vth shifts to the enhancement side, and the shift amount Vdd exceeds a voltage that can be dealt with due to an increase in the supply voltage in the power supply circuit, for example, in about 1000 hours. On the other hand, in each of the examples in which nitrogen atoms are introduced into the vicinity 203 of the interface, the deviation amount Vdd decreases in accordance with the introduction amount. In particular, it can be seen that the higher the nitrogen gas concentration, the more the increase in the deviation amount Vdd is suppressed.

As described in detail above, according to the substrate device of the first embodiment, the transistor characteristics of the TFTs forming the peripheral drive circuit section are deteriorated with time, and the transistor characteristics are particularly high in operating environments such as high humidity and high temperature. Can be reduced. As a result, by providing the peripheral drive circuit unit with a TFT capable of maintaining stable performance over a long period of time regardless of the use environment, the life of the substrate device can be extended. Then, as shown in FIGS. 1 and 2, according to the first embodiment, a substrate device having such a configuration can be manufactured relatively easily.

Depending on the specifications of the substrate device in the above-described embodiment, the type of impurities doped into the semiconductor layer 1a may be changed to construct an N-channel type TFT or a P-channel type TFT. A TFT may be constructed. For example, when the TFT in the pixel portion is an N-channel type which is more excellent in basic performance such as carrier mobility and device life, high-quality image display can be possible. On the other hand, the TFT in the peripheral drive circuit is replaced by a CMOS (Complementary
By using the MOS type TFT, the N-channel type TFT portion can be formed at the same time as the TFT in the pixel portion, and the manufacturing process can be simplified. Further, regarding the P-channel type TFT portion, the gate insulating film 2b is made of an oxynitride film, so that the life of the device can be extended, thereby extending the device life as a whole. In this case, in particular, in the case of the P-channel TFT in the peripheral drive circuit section, the gate insulating film 2b is made of an oxynitride film if it is provided in the peripheral drive circuit as a switching element that is turned on / off when the gate voltage exceeds the threshold value. It is possible to prevent the variations in transistor characteristics and the deterioration of carrier mobility due to the above from being surfaced as an adverse effect. In any case, it has been confirmed that introduction of nitrogen into the gate insulating film 2b of the P-channel type TFT in the peripheral drive circuit section prolongs the life of the TFT remarkably. By introducing nitrogen into the film, the effect of extending the life of transistor characteristics can be obtained.

Further, in this embodiment, in the step (2) of FIG. 1, nitrogen is introduced into the gate insulating film 2b by performing annealing in a furnace in a gas atmosphere containing nitrogen atoms. It may be done by some plasma technique, lamp annealing, laser annealing or ion implantation. In particular, the oxidation and the introduction of nitrogen may be simultaneously performed as one oxynitriding step, or the nitrogen introduction step may be continuously performed after the oxidation step.

(Second Embodiment of Substrate Device) Next, with reference to FIGS. 5 and 6, a manufacturing method and a structure of a substrate device according to a second embodiment of the present invention will be described. 5 and 6 show the second
FIG. 6 is a process chart showing the manufacturing method of the embodiment in order, which is a pixel switching TFT provided in the pixel portion (in the figure,
The left half surface) and the TFT (right half surface in the drawing) forming the peripheral drive circuit are respectively shown in cross sectional structures in the vicinity of the TFT for each step. 5 and 6, the same components as those of the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 5, after the step (1) is performed as in the first embodiment, in step (2), for example, a reduced pressure C
The nitride film 700 is formed on the entire surface of the semiconductor layer 1a in the peripheral circuit portion and the pixel portion by VD (Chemical Vapor Deposition) or the like.

Next, in step (3), the semiconductor layer 1a in the pixel portion is masked with the resist 604, and in step (4), the nitride film 700 in the portion not masked with the resist 604 is removed by etching. As a result, a structure is obtained in which the semiconductor layer 1a in the pixel portion is covered with the mask made of the nitride film 700.

Next, in step (5), a thermally oxidized silicon film is first formed on the surface of the semiconductor layer 1a of the peripheral drive circuit section by dry oxidation or wet oxidation, and then in a furnace (diffusion furnace). By annealing in a gas atmosphere containing nitrogen atoms, the gate insulating film 2b having nitrogen atoms introduced therein is formed. Since the nitride film is hard to be oxidized, almost no oxide film is formed on the nitride film 700 at the same time when the gate insulating film 2b is formed.

Then, in step (6), 140 to 170
The nitride film 700 is selectively removed by etching using an etchant 503 of hot phosphoric acid or the like at about ℃. At this time, the gate insulating film 2b made of an oxynitride film is hardly etched and removed by hot phosphoric acid or the like. As a result, in the pixel portion, the semiconductor layer 1a is exposed again. On the other hand, the structure in which the gate insulating film 2b made of an oxynitride film is formed on the semiconductor layer 1a of the peripheral circuit portion is maintained.

Then, in step (7) of FIG. 6, a gate insulating film 2a made of a thermally oxidized silicon film or the like is formed on the surface of the semiconductor layer 1a in the pixel portion by dry oxidation, wet oxidation, or an HTO film.

Next, in the step (8), the gate electrodes 3a and 3b made of a conductive polysilicon film or the like are formed on the gate insulating film, respectively, and in the step (9), the source electrode and the drain electrode are connected. Contact holes are formed by dry etching, wet etching, or a combination of the two. Through these holes, as shown by the broken line in the figure, in the pixel portion, from the end portion of the data line 6a made of Al or the like and from the ITO or the like. The end portion of the pixel electrode 9a is connected as a source electrode and a drain electrode. Before or after this, or in parallel with this, in the peripheral drive circuit section, the wirings 6b and 6c made of Al or the like are connected as a source electrode and a drain electrode.

Through the above steps (1) to (9), the substrate 1
TFTs are respectively constructed in the pixel portion and the peripheral drive circuit portion on the 0.

As described in detail above, according to the substrate device of the second embodiment, the transistor characteristics of the TFTs forming the peripheral drive circuit portion are deteriorated with time, and the transistor characteristics are particularly high in operating environments such as high humidity and high temperature. Can be reduced. As a result, by providing the peripheral drive circuit unit with a TFT capable of maintaining stable performance over a long period of time regardless of the use environment, the life of the substrate device can be extended. Then, as shown in FIGS. 5 and 6, according to the second embodiment, the substrate device having such a configuration can be manufactured relatively easily.

(Third Embodiment of Substrate Device) Next, a manufacturing method and a structure of a substrate device according to a third embodiment of the present invention will be described with reference to FIG. 7A to 7C are process diagrams sequentially showing the manufacturing method of the third embodiment. The pixel switching TFT (left half surface in the drawing) provided in the pixel portion and the TFT configuring the peripheral drive circuit (in the drawing, The right half surface) shows the cross-sectional structure near the TFT in each step. In FIG. 7, the same components as those of the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 7, after the step (1) is performed as in the first embodiment, in the step (2), the surface of the semiconductor layer 1a in the pixel portion is formed by dry oxidation or wet oxidation.
First, the gate insulating film 2a made of a thermally oxidized silicon film is formed. At the same time, the same film 2a 'as the gate insulating film 2b is formed also in the peripheral drive circuit section.

Next, in step (3), the gate insulating film 2a in the pixel portion is masked with the mask 605 made of a nitride film. Subsequently, in step (4), by annealing in a furnace (diffusion furnace) in an atmosphere of a gas 505 containing nitrogen atoms, an insulating film 2a ′ in the peripheral drive circuit portion not covered with the mask 605 is formed. A gate insulating film 2b into which nitrogen atoms are introduced is formed.

Then, the mask 605 is peeled off to form the gate insulating film 2a made of an oxide film on the semiconductor layer 1a in the pixel portion, and the oxynitride is formed on the semiconductor layer 1a in the peripheral circuit portion. A structure in which the gate insulating film 2b made of a film is formed is obtained.

Thereafter, the same manufacturing process as steps (7) to (9) in the first embodiment shown in FIG. 2 is performed, whereby TFTs are constructed in the pixel section and the peripheral drive circuit section on the substrate 10, respectively. To be done.

As described in detail above, according to the substrate device of the third embodiment, the transistor characteristics of the TFTs forming the peripheral drive circuit portion are deteriorated with time, and the transistor characteristics are particularly high in operating environments such as high humidity and high temperature. Can be reduced. As a result, by providing the peripheral drive circuit unit with a TFT capable of maintaining stable performance over a long period of time regardless of the use environment, the life of the substrate device can be extended. Then, as shown in FIG. 7, according to the third embodiment, a substrate device having such a configuration can be manufactured relatively easily.

In the above-described first to third embodiments, the peripheral drive circuit is formed directly on the substrate 10 by the thin film forming process. However, after the peripheral drive circuit section is formed on another substrate, It is also possible to manufacture a drive circuit built-in type substrate device by adhering it to the peripheral region of the substrate 10.

(Example of Configuration of Pixel Section in Embodiment of Electro-Optical Device) Next, an embodiment of an electro-optical device including the substrate device of the present invention will be described with reference to FIGS. This embodiment is provided with any one of the first to third embodiments of the above-mentioned substrate device as a TFT array substrate, and the TFT array substrate and the counter substrate are arranged so as to face each other, and a liquid crystal or the like is provided therebetween. It is an embodiment according to an electro-optical device in which the electro-optical substance is sandwiched. Here, FIG. 8 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixels that are formed in a matrix and form an image display region of the electro-optical device. 9 is a plan view of a plurality of pixel groups adjacent to each other on a TFT array substrate on which data lines, scanning lines, pixel electrodes, etc. are formed, and FIG. 10 is a sectional view taken along line AA ′ of FIG.
Note that, in FIG. 10, the scales of the layers and members are made different in order to make the layers and members recognizable in the drawing.

In FIG. 8, in particular, in the electro-optical device of the present embodiment including the first to third embodiments of the above-mentioned substrate device as a TFT array substrate, the electro-optical device is formed in a matrix forming the image display area. The plurality of pixels includes a pixel electrode 9a and a TFT 3 for controlling the pixel electrode 9a.
A plurality of 0s are formed in a matrix, and the data line 6a to which the image signal is supplied is electrically connected to the source of the TFT 30. The scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2, ...
Gm is line-sequentially applied in this order. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and by closing the switch of the TFT 30, which is a switching element, for a certain period, the image signals S1, S2, ..., Sn supplied from the data line 6a are transmitted. Write at a predetermined timing. An image signal S1 of a predetermined level written in the electro-optical material via the pixel electrode 9a,
S2, ..., Sn are held for a certain period of time between a counter electrode (described later) formed on a counter substrate (described later). The electro-optical material modulates light by changing the orientation and order of the molecular assembly depending on the applied voltage level, and enables gradation display. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is added in parallel with the electro-optical material capacitor formed between the pixel electrode 9a and the counter electrode.

In FIG. 9, in particular, in the electro-optical device of the present embodiment which is provided with the first to third embodiments of the above-described substrate device as a TFT array substrate, a plurality of transparent substrates arranged in a matrix on the TFT array substrate. Pixel electrode 9a
The data line 6a, the scanning line 3a and the capacitance line 3b are provided along the vertical and horizontal boundaries of the pixel electrode 9a.
The data line 6a is electrically connected to a later-described source region of the semiconductor layer 1a made of a polysilicon film or the like via the contact hole 5, and the pixel electrode 9a is connected to the source layer of the semiconductor layer 1a via the contact hole 8. It is electrically connected to a drain region described later. In addition, the scanning line 3a is arranged so as to face the channel region (the region of the oblique line that is slanted to the lower right in the drawing) of the semiconductor layer 1a, and the scanning line 3a functions as a gate electrode. The capacitance line 3b has a main line portion that extends substantially linearly along the scanning line 3a, and a protruding portion that protrudes from the position intersecting the data line 6a to the front side (upward in the figure) along the data line 6a. . In addition, the island-shaped first light-shielding film 11a is provided in each of the rectangular island-shaped regions indicated by the thick lines in the drawing at a position that covers at least the channel region of each TFT for each pixel when viewed from the TFT array substrate side. Has been.

Next, as shown in the sectional view of FIG. 10, the electro-optical device comprises a transparent TFT array substrate 10 and a transparent counter substrate 20 arranged to face the TFT array substrate 10. TFT
The array substrate 10 is made of, for example, a quartz substrate, and the counter substrate 20 is made of, for example, a glass substrate or a quartz substrate. TFT
The array substrate 10 is provided with the pixel electrodes 9a,
An alignment film 16 that has been subjected to a predetermined alignment process such as a rubbing process is provided on the upper side thereof. The pixel electrode 9a is made of, for example, a transparent conductive film such as an ITO film (Indium Tin Oxide film). The alignment film 16 is made of, for example, an organic film such as a polyimide film. On the other hand, the counter substrate 20 is provided with a counter electrode (common electrode) 21 over the entire surface thereof, and an alignment film 22 subjected to a predetermined alignment treatment such as a rubbing treatment is provided below the counter electrode 21. ing. As shown in FIG. 10, the TFT array substrate 10 is provided with a pixel switching TFT 30 for controlling switching of each pixel electrode 9a at a position adjacent to each pixel electrode 9a. As shown in FIG. 10, the counter substrate 20 further includes a second area in the area other than the opening area of each pixel (that is, an area in the image display area where incident light is actually transmitted and contributes effectively to the display).
A light shielding film 23 is provided.

A sealing material described later (see FIGS. 17 and 18) is provided between the TFT array substrate 10 and the counter substrate 20 which are arranged as described above and are arranged so that the pixel electrode 9a and the counter electrode 21 face each other. The electro-optical material such as liquid crystal is enclosed in the space surrounded by the parentheses to form the electro-optical material layer 50. The electro-optical material layer 50 has a predetermined alignment state by the alignment films 16 and 22 in a state where the electric field from the pixel electrode 9a is not applied. The electro-optical material layer 50 is made of, for example, an electro-optical material in which one kind or several kinds of nematic liquid crystals are mixed. The sealing material is the TFT substrate 10 and the counter substrate 2
It is an adhesive made of, for example, a photo-curable resin or a thermo-curable resin for bonding 0 around them, and a spacer such as glass fiber or glass beads for mixing a predetermined distance between both substrates is mixed. Has been done.

9 and 10, in the present embodiment, the data line 6a, the scanning line 3a, the capacitance line 3b, and the T line.
7, the TFT array substrate 10 is recessed in a mesh-shaped region including the FT 30 and which is hatched in the upper right direction in FIG. 7, and a groove for flattening the image display region is formed.

As shown in FIG. 10, between the TFT array substrate 10 and the pixel switching TFTs 30 at positions facing the pixel switching TFTs 30, respectively,
The first light shielding film 11a is provided in an island shape for each pixel.
The first light-shielding film 11a is preferably composed of a simple metal, an alloy, a metal silicide, or the like containing at least one of Ti, Cr, W, Ta, Mo, and Pb which are opaque refractory metals.

Further, the first interlayer insulating film 12 is provided between the first light shielding film 11a and the plurality of pixel switching TFTs 30.
Is provided. The first interlayer insulating film 12 is provided to electrically insulate the semiconductor layer 1a forming the pixel switching TFT 30 from the first light shielding film 11a. Further, the first interlayer insulating film 12 is formed on the TFT array substrate 1
When it is formed on the entire surface of 0, it also functions as a base film for the pixel switching TFT 30.

In the present embodiment, the gate insulating film 2 is extended from the position facing the scanning line 3a and used as a dielectric film, and the semiconductor layer 1a is extended to form the first storage capacitor electrode 1f. The storage capacitor 70 is configured by using a part of the capacitance line 3b facing the second storage capacitor electrode as a second storage capacitor electrode.

In FIG. 10, the pixel switching TF is used.
T30 has an LDD (Lightly Doped Drain) structure, and includes the scanning line 3a and the channel region 1 of the semiconductor layer 1a in which a channel is formed by the electric field from the scanning line 3a.
a ′, the gate insulating film 2 that insulates the scanning line 3a from the semiconductor layer 1a, the data line 6a, the low-concentration source region 1b and the low-concentration drain region 1c of the semiconductor layer 1a, the high-concentration source region 1d of the semiconductor layer 1a, and the high-concentration source region 1d. It has a concentration drain region 1e. A corresponding one of the plurality of pixel electrodes 9a is connected to the high concentration drain region 1e. In the present embodiment, especially the data line 6a is composed of a light-shielding thin film such as a low resistance metal film such as Al or an alloy film such as metal silicide. The high-concentration source region 1d is formed on the scan line 3a, the gate insulating film 2, and the first interlayer insulating film 12.
Contact hole 5 and high-concentration drain region 1 leading to
The second interlayer insulating film 4 in which the contact holes 8 leading to e are formed is formed. Furthermore, on the data line 6a and the second interlayer insulating film 4, a third interlayer insulating film 7 in which a contact hole 8 to the high concentration drain region 1e is formed is formed.

The pixel switching TFT 30 preferably has the LDD structure as described above, but may have the offset structure in which the impurity ions are not implanted into the low concentration source region 1b and the low concentration drain region 1c, or the scanning line. A self-aligned TFT in which high-concentration source and drain regions are formed in a self-aligned manner by implanting impurity ions at a high concentration using the gate electrode that is a part of 3a as a mask may be used. Further, in the present embodiment, the single gate structure in which only one gate electrode of the pixel switching TFT 30 is arranged between the source-drain regions is adopted, but two or more gate electrodes may be arranged between them. At this time, the same signal is applied to each gate electrode.

(Structural Example of Peripheral Driving Circuit Section in Embodiment of Electro-Optical Device) Next, referring to FIG. 11 to FIG.
A configuration example of the peripheral drive circuit will be described.

First, with reference to FIGS. 11 to 13, a shift register circuit built as a part of the drive circuit in the peripheral region of the electro-optical device will be described. here,
FIG. 11 is an equivalent circuit diagram showing an example of an equivalent circuit of this shift register circuit. 12A shows an example of a layout plan view of the S portion of the shift register circuit of FIG. 11 on the substrate, and FIG. 12B shows FIG. 12A.
FIG. 9 is a sectional view taken along line CC ′ of FIG. 13A shows another example of a layout plan view on the substrate of the S portion of the shift register circuit of FIG. 11, and FIG. 13B shows FIG.
It is a DD 'sectional view of (A). 11 to 13
In the above, in the case of the embodiment relating to the pixel section of the electro-optical device shown in FIG. 8 to FIG. 10 described above, the same constituent elements are designated by the same reference numerals, and the description thereof will be omitted. Further, in FIG. 13, the same components as those in FIG. 12 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 11, the shift register circuit is
It is configured to include a large number of CMOS type TFTs. Of these, at least for the P-channel TFT, the gate insulating film is composed of an oxynitride film introduced with nitrogen as in the first to third embodiments described above. Further, in this example, the circuit that latches the transfer signal may be configured by a transmission gate circuit, a clocked inverter circuit, or the like.

The example shown in FIGS. 12A and 12B has a P-type region 250 and an N-type region 251, and is provided with a P-channel TFT 246 which constitutes a drive circuit. A clock signal line CL for controlling the transmission gate circuit in order to pass the wiring through a connection portion N4 between the shift register circuit of the main stage and the shift register circuit of the next stage.
On the second interlayer insulating film 4 formed on the surface of the wiring, the wiring 240 made of a metal film of Al or the like between the same layers formed in the same step as the data line is used. Then, the source / drain electrodes 241 and 2 of the transmission gate circuit
42 is formed in the same layer as the wiring 240.

In the examples shown in FIGS. 13A and 13B, a conductive light-shielding film 11a is formed between the substrate 10 and the base insulating film 12, and the shift register circuit and It is used as the wiring material of the connection portion N4 with the shift register circuit of the stage. This eliminates wiring between the same layers as the source and drain electrodes 241 and 242 of the transmission gate circuit.

Next, with reference to FIGS. 14 to 16, the clocked inverter circuit, the transmission gate circuit and the inverter circuit forming the peripheral drive circuit will be described. Here, FIG. 14A shows an example of an equivalent circuit used in a peripheral driver circuit, which shows a clocked inverter circuit, FIG. 14B shows a transmission gate circuit, and FIG. The inverter circuit is shown.
15A is a plan view showing a layout on a substrate for a liquid crystal device in a specific example of the inverter circuit of FIG. 14C, and FIG. 15B is a line E- of FIG. E '
The cross-sectional view in between is shown. In addition, FIG.
4C is a plan view of the layout on the liquid crystal device substrate 300 in another specific example of the inverter circuit of FIG.
16B shows a cross-sectional view taken along the line FF 'in FIG. 16A, and FIG. 16C shows a cross-sectional view taken along the line GG' in FIG. 16A. 14 to 16, the same components as those in FIGS. 11 to 13 described above are designated by the same reference numerals, and the description thereof will be omitted.

14 (A), 14 (B) and 14
As shown in (C), each equivalent circuit is composed of a CMOS TFT including a P-channel TFT 246 and an N-channel TFT 247. In these figures, CL is a clock signal, CLB is an inverted signal of the clock signal, VDD is a constant voltage power supply on the high potential side of the peripheral drive circuit, and VSS is a constant voltage power supply on the low potential side of the peripheral drive circuit. There is. Of these, at least the P-channel TFT 246 has a gate insulating film made of a nitrogen oxide film into which nitrogen is introduced as described in the first to third embodiments.

In one specific example shown in FIGS. 15A and 15B, a P-channel type T which constitutes an inverter circuit is used.
The light-shielding film 11a is connected to the source electrode 244 of each of the FT 246 and the N-channel TFT 247 via the contact hole 205 of the base insulating film 12. The light-shielding film 11 a is formed so as to completely cover the channel regions 252 and 253 below the gate electrodes 243 of the P-channel TFT 246 and the N-channel TFT 247 via the underlying insulating film 12. Therefore, the P-channel TFT 24
6 of the source electrode 248 (constant voltage power supply VDD on the high potential side of the peripheral drive circuit) and the source electrode 249 of the N-channel TFT 247 (constant voltage power supply VS on the low potential side of the peripheral drive circuit).
The light shielding film 11a functions as a pseudo second gate electrode by the voltage applied from S). Therefore, in the N-channel TFT 247, the potential of the portion of the depletion layer that is in contact with the gate insulating film 2 in the channel region 253 rises more than before, and the potential energy for electrons decreases. As a result, electrons gather at the portion of the depletion layer in contact with the gate insulating film 2 and an inversion layer is easily formed, so that the resistance of the semiconductor layer is lowered and the TFT characteristics are improved.
In the channel region 252 of the P-channel TFT 246,
A phenomenon occurs in which the electrons are replaced with holes.

In FIG. 15B, the P-channel type TFT 246 and the N-channel type TFT 247 of the peripheral drive circuit are represented by the gate self-aligned structure, but as described in the manufacturing process, the withstand voltage of the TFT is improved and the reliability is improved. P-channel TFT 24 of the peripheral drive circuit for improving
The 6 and N-channel TFTs 247 may be formed with an LDD structure or an offset gate structure.

In another concrete example shown in FIGS. 16A and 16B, a P-channel type T constituting an inverter circuit is used.
The light-shielding film 11a formed so as to overlap the gate electrodes 243 of the FT 246 and the N-channel TFT 247 is connected to the gate electrode 243. Further, the light-shielding film 11a is the same as or narrower in width than the gate electrode 243, and the upper and lower portions of the channel regions 252, 253 are sandwiched by the gate electrode 243 and the light-shielding film 11a with the gate insulating film 2 and the underlying insulating film 12 interposed therebetween. A gate structure TFT is constructed.
Further, the input side wiring 244 of the inverter circuit is formed in the same layer as the data line, is connected to the gate electrode 243 through the contact hole 205 of the base insulating film 12, and contacts the contact hole 205 of the base insulating film 12. Is connected to the light-shielding film 11a via. Contact hole 205
The same step is used to open the holes. Therefore, in this double-gate structure TFT, the light-shielding film 11a functions as the second gate electrode, and the back channel effect causes the TFT
It is possible to further improve the characteristics.

(Example of Overall Configuration in Embodiment of Electro-Optical Device) Next, with reference to FIGS. 17 and 18, an overall configuration of the electro-optical device configured as described above will be described. Note that FIG. 17 is a plan view of the TFT array substrate 10 together with the components formed thereon as viewed from the side of the counter substrate 20, and FIG. 18 is a plan view taken along line H- of FIG.
It is a H'sectional view.

In FIG. 17, the sealing material 52 is provided on the TFT array substrate 10 along the edge thereof, and in parallel with the inside thereof, for example, is made of the same or different material as the second light-shielding film 23. Third light-shielding film 53 as a frame
Is provided. The data line driving circuit 101 and the external circuit connecting terminal 102 are provided in a region outside the sealing material 52.
The scanning line driving circuit 104 is provided along one side of the FT array substrate 10, and the scanning line driving circuit 104 is provided along two sides adjacent to the one side. Furthermore, on the remaining one side of the TFT array substrate 10, a plurality of wirings 105 for connecting the scanning line driving circuits 104 provided on both sides of the image display area are provided. The TFT array substrate 10 and the counter substrate 2 are provided at least at one corner of the counter substrate 20.
An upper and lower conducting member 106 is provided to establish electrical conduction with 0. Then, as shown in FIG.
Counter substrate 2 having substantially the same contour as the sealing material 52 shown in FIG.
0 is fixed to the TFT array substrate 10 by the sealing material 52.

In the embodiment of the electro-optical device described above with reference to FIGS. 17 to 18, the data line driving circuit 101 is provided.
Instead of providing the scanning line driving circuit 104 on the TFT array substrate 10, a driving LSI mounted on, for example, a TAB (tape automated bonding substrate).
In addition, the TFT array substrate 10 may be electrically and mechanically connected via an anisotropic conductive film provided in the peripheral portion. Further, an electro-optical device capable of high-quality image display can be realized by applying the present invention to any system such as a TFD active matrix system and a passive matrix drive system other than the TFT active matrix drive system. Furthermore, in the electro-optical device described above, the outer surface of the counter substrate 20 and the outer surface of the TFT array substrate 10 are respectively
For example, TN (Twisted Nematic) mode, VA (Vertic
ally aligned mode, PDLC (Polymer Dispersed Li)
A polarizing film, a retardation film, a polarizing plate, etc. are arranged in a predetermined direction according to an operation mode such as a quid crystal mode or a normally white mode / a normally black mode.

(Embodiment of Electronic Equipment) Next, with respect to an embodiment of a projection type color display device which is an example of an electronic equipment using the electro-optical device described in detail above as a light valve, its entire configuration, particularly optical The configuration will be described. FIG. 19 is a schematic sectional view of the projection type color display device.

In FIG. 19, a liquid crystal projector 1100 which is an example of the projection type color display device in this embodiment.
Prepares three liquid crystal modules including the liquid crystal device 100 in which the driving circuit is mounted on the TFT array substrate.
It is configured as a projector used as the B light valves 100R, 100G, and 100B. In the liquid crystal projector 1100, when the projection light is emitted from the lamp unit 1102 of the white light source such as a metal halide lamp, the three mirrors 1106 and the two dichroic mirrors 1108 cause the light components R, G corresponding to the three primary colors of RGB, It is divided into B and is led to the light valves 100R, 100G and 100B corresponding to the respective colors. At this time, in particular, the B light is
It is guided through a relay lens system 1121 including an entrance lens 1122, a relay lens 1123, and an exit lens 1124. The light components corresponding to the three primary colors modulated by the light valves 100R, 100G, and 100B are recombined by the dichroic prism 1112, and then the screen 11 via the projection lens 1114.
20 is projected as a color image.

The present invention is not limited to the above-described embodiments, but may be modified as appropriate without departing from the scope or spirit of the invention that can be read from the claims and the entire specification, and such modifications are accompanied. The substrate device, the manufacturing method thereof, and the electro-optical device are also included in the technical scope of the present invention.

[Brief description of drawings]

FIG. 1 is a process chart (1) sequentially showing a manufacturing method of a first embodiment of a substrate device of the present invention.

2A to 2C are process diagrams (2) sequentially showing the manufacturing method of the first embodiment of the substrate device of the present invention.

3 is a characteristic showing the nitrogen concentration introduced in the step (2) of FIG. 1 and the secondary strengths of oxygen and silicon in the portion from the gate insulating film to the semiconductor layer with respect to the depth from the surface of the gate insulating film. It is a figure.

FIG. 4 is a characteristic diagram showing a deviation amount Vdd (V) from an initial value of a threshold value Vth with respect to an operating time in a plurality of examples in which the introduction amount of nitrogen atoms is changed and a comparative example in which a nitrogen atom is not introduced.

5A to 5C are process diagrams (1) sequentially showing the manufacturing method of the second embodiment of the substrate device of the present invention.

FIG. 6 is a process diagram (No. 2) sequentially showing the manufacturing method of the second embodiment of the substrate device of the present invention.

7A to 7C are process diagrams sequentially showing a manufacturing method of a third embodiment of the substrate device of the present invention.

FIG. 8 is an equivalent circuit of various elements, wirings and the like provided in a plurality of pixels in a matrix forming an image display area in the embodiment of the electro-optical device of the invention.

9 is a plan view of a plurality of pixel groups adjacent to each other on a TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed in the electro-optical device of FIG.

10 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 11 is an equivalent circuit diagram showing an example of a shift register circuit that constitutes a peripheral drive circuit in the embodiment.

12A is an S diagram of the shift register circuit of FIG.
It is a layout top view on a board | substrate of an example of a part, (B) is CC 'sectional drawing of (A).

13A is an S diagram of the shift register circuit of FIG.
It is a layout top view on the board of the other example of a portion, and (B) is a DD 'sectional view of (A).

14A is a circuit diagram of a clocked inverter circuit, which is an example of an equivalent circuit used in a peripheral drive circuit, FIG. 14B is a circuit diagram showing a transmission gate circuit, and FIG. FIG. 3 is a circuit diagram showing an inverter circuit.

15A is a plan view showing a layout on a substrate for a liquid crystal device in a specific example of the inverter circuit of FIG. 14C, and FIG. 15B is a cross-sectional view taken along line EE ′ of FIG. FIG.

16A is a plan view of a layout on a liquid crystal device substrate 300 in another specific example of the inverter circuit of FIG. 14C, and FIG. 16B is a FF ′ cross section of FIG. It is a figure and (C) is a GG 'sectional view of (A).

FIG. 17 shows T in the embodiment of the electro-optical device of the present invention.
It is the top view which looked at the FT array substrate with each component formed on it from the counter substrate side.

18 is a cross-sectional view taken along the line H-H ′ of FIG.

FIG. 19 is a schematic cross-sectional view showing a color liquid crystal projector which is an example of a projection type color display device which is an embodiment of an electronic apparatus of the invention.

[Explanation of symbols]

1a ... semiconductor layer 2a ... Gate insulating film (oxide film) 2b ... Gate insulating film (oxynitride film) 3a ... scanning line 3b ... Capacity line 5 ... Contact hole 6a ... Data line 8 ... Contact hole 9a ... Pixel electrode 10 ... TFT array substrate 10a ... Image display area 11a ... First light-shielding film 20 ... Counter substrate 21 ... Counter electrode 23 ... Second light-shielding film 30 ... Pixel switching TFT 50 ... Electro-optical material layer 52 ... Sealing material 70 ... Storage capacity 101 ... Data line drive circuit 104 ... Scan line drive circuit 601 to 604 ... Mask 700 ... Nitride film

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/8238 H01L 29/78 612B 5G435 27/08 331 617T 27/092 617V 29/786 627F 27/08 321D F term ( (Reference) 2H092 GA11 GA17 GA31 GA35 GA43 GA59 GA60 HA00 HA01 HA11 JA00 JA24 JA34 KA04 KA05 KA11 KA12 MA02 MA06 MA08 MA14 MA15 MA26 MA27 MA30 NA01 NA21 NA30 2H093 NC09 NC11 NC32 NC34 NC67 ND07 ND48 ND A01 A02 ND4801 ND52 A02 CA19 DA15 EA04 EA07 FB15 GB10 5F048 AC04 BA16 BB09 BB11 BE08 BG07 5F110 AA14 BB02 BB04 CC02 DD01 DD02 DD03 DD13 EE02 EE04 EE05 EE06 EE09 EE27 EE30 FF02 FF04 FF21 FF23 FF26 GG02 GG13 GG15 HL03 HL05 HL06 HL07 HM14 HM15 NN03 NN44 NN46 NN72 NN73 NN78 QQ11 5G435 AA14 AA17 BB12 CC09 EE37 HH13 HH14 KK05 KK09

Claims (17)

[Claims] 1. A substrate, a pixel electrode and a first transistor connected to the pixel electrode in an image display region on the substrate, and a peripheral region located around the image display region on the substrate. A wiring for driving the first transistor and a second transistor forming a part of a drive circuit connected to the wiring, wherein the first gate insulating film forming the first transistor is nitrogen. And a second gate insulating film that constitutes the second transistor,
A substrate device comprising an oxynitride film into which nitrogen is introduced. 2. The substrate device according to claim 1, wherein the second transistor is a P-channel type TFT or a CMOS (Complementary MOS) type TFT. 3. The substrate device according to claim 1, wherein the first transistor is an N-channel TFT. 4. The substrate device according to claim 1, wherein the semiconductor layers forming the first and second transistors are made of low temperature or high temperature polysilicon or amorphous silicon. 5. The second transistor is provided in the drive circuit as a switching element which is turned on / off when a gate voltage thereof exceeds a threshold value, according to any one of claims 1 to 4. The substrate device described. 6. The substrate device according to claim 1, wherein the second transistor is formed on another substrate and then attached to the peripheral region. 7. A substrate device manufacturing method for manufacturing the substrate device according to claim 1, wherein the first semiconductor layer and the first semiconductor layer forming the first transistor are provided on the substrate. A semiconductor layer forming step of forming a second semiconductor layer forming a second transistor; an oxynitride film forming step of forming an oxynitride film on the first and second semiconductor layers; and a step of forming the oxynitride film. A removing step of selectively removing a portion of the oxynitride film formed on the first semiconductor layer while masking a portion of the oxynitride film formed on the second semiconductor layer; An oxide film forming step of forming the oxide film on the removed first semiconductor layer; and a gate electrode forming step of forming gate electrodes on the formed oxynitride film and oxide film, respectively. A method of manufacturing a characteristic substrate device. 8. A method of manufacturing a substrate device according to any one of claims 1 to 6, wherein the first semiconductor layer forming the first transistor and the first semiconductor layer are formed on the substrate. A semiconductor layer forming step of forming a second semiconductor layer forming a second transistor; a nitride film forming step of selectively forming a nitride film on the first semiconductor layer while masking the second semiconductor layer; An oxynitride film forming step of selectively forming an oxynitride film on the second semiconductor layer on which no film is formed, a removing step of removing the nitride film, and a first semiconductor layer on which the nitride film is removed And a gate electrode forming step of forming a gate electrode on the formed oxynitride film and the oxide film, respectively. 9. A method of manufacturing a substrate device according to any one of claims 1 to 6, comprising: a first semiconductor layer forming the first transistor on the substrate; A semiconductor layer forming step of forming a second semiconductor layer forming a second transistor; an oxide film forming step of forming an oxide film on the first and second semiconductor layers; and an oxide formed on the first semiconductor layer. An oxynitride film forming step of selectively forming an oxynitride film on an oxide film formed on the second semiconductor layer while masking the film with a nitride film; and forming the oxynitride film and the oxide film on the formed oxide film, respectively. And a gate electrode forming step of forming a gate electrode. 10. A method of manufacturing a substrate device according to any one of claims 1 to 6, wherein the first semiconductor layer forming the first transistor and the first semiconductor layer are formed on the substrate. A semiconductor layer forming step of forming a second semiconductor layer forming a second transistor; and an oxide film for selectively forming an oxide film on the first semiconductor layer while masking the second semiconductor layer with a nitride film or a resist. A forming step, an oxynitride film forming step of selectively forming an oxynitride film on the second semiconductor layer after removing the nitride film, and a gate electrode on the formed oxynitride film and oxide film, respectively. And a gate electrode forming step of forming the substrate electrode. 11. The oxynitride film forming step includes a step of oxidizing in an atmosphere containing nitrogen.
11. The method for manufacturing a substrate device according to claim 10. 12. The oxynitride film forming step comprises N ₂ O (dinitrogen monoxide) gas, NO (mononitrogen monoxide) gas and NH.
_The method for manufacturing a substrate device according to claim 11, further comprising a step of annealing in an atmosphere containing at least one of ₄ (ammonia) gas. 13. The oxynitride film forming step includes any one step of vertical or horizontal diffusion furnace, nitriding using plasma, lamp annealing, laser annealing, or ion implantation. 13. The method for manufacturing a substrate device according to any one of 1 to 12. 14. The method of manufacturing a substrate device according to claim 7, wherein the oxynitride film forming step includes a step of doping nitrogen after forming an oxide film. 15. The method according to claim 7, further comprising a thinning step of thinning an oxide film or an oxynitride film formed on the first and second semiconductor layers. A method for manufacturing the substrate device described. 16. An electro-optical device comprising the substrate device according to claim 1. Description: 17. An electronic apparatus comprising the electro-optical device according to claim 16.