JP2003248239A - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: Provided is a liquid crystal display device capable of preventing a peripheral circuit from being destroyed by static electricity generated in a rubbing process, and a method for manufacturing the same. When patterning a light shielding material constituting a black matrix, a shield film covering a wiring connected to a drain of a thin film transistor in a peripheral portion.
By forming 0b, in the rubbing process, even when the roller comes into contact with the flattening film 21 in the peripheral portion of the transparent insulating substrate 10 and the roller rubs the flattening film 21, static electricity is generated. The static electricity is
Accumulation in the shield film 20b and accumulation in the wiring 17b connected to the drain of the thin film transistor in the peripheral portion are prevented.

Description

Detailed Description of the Invention

[0001]

The present invention relates to, for example, a TFT.
The present invention relates to a liquid crystal display device using (Thin Film Transistor) and a manufacturing method thereof.

[0002]

2. Description of the Related Art In the manufacture of liquid crystal display devices, it is necessary to form an alignment film in order to align the molecular alignment of the liquid crystal layer, and this alignment film is subjected to alignment treatment by a rubbing method. In the rubbing method, for example, a rubbing cloth such as felt or cotton is wound around the roller to rotate the roller, and the TFT substrate placed on the table is moved in a direction reverse to the roller rotation direction while keeping contact with the roller. Let

At this time, by stretching the alignment film by rubbing, the major axis directions of the alignment film molecules are made uniform. Therefore, when the alignment film is subsequently filled with liquid crystal, the liquid crystal molecules can be aligned due to the effect that the long axis directions of the liquid crystal molecules and the alignment film molecules are aligned and are in an energy stable state.

In the above-mentioned alignment film forming step and rubbing treatment step, an alignment film is formed on a pixel portion of a substrate divided into a pixel portion and a peripheral portion, and the above-mentioned rubbing treatment is applied to the alignment film. Done.

FIG. 16A shows a plan view of, for example, a transfer gate which constitutes a peripheral circuit, and FIG. 16B shows a sectional view taken along the line BB 'of FIG. 16A.

As shown in FIG. 16 (a), the peripheral circuit of the liquid crystal display device is usually formed by thin film transistors. For example, the drains of the n-channel transistor n-Tr and the p-channel transistor p-Tr formed of TFTs are used. The gates are commonly connected to the wiring 17b made of aluminum or the like, and the sources are commonly connected to the wiring 17c made of aluminum or the like to form a transfer gate. The above transfer gate is, for example,
It is used as a switching element when writing video signals etc. to the pixel part, and it is used as the gate electrode 1 of each transistor.
By applying a desired voltage to 5b and 15d, the transfer gate is turned on, and a desired video signal is supplied from the wiring 17b connected to the drain to the pixel portion through the wiring 17c.

As shown in FIG. 16B, the thin film transistor constituting the transfer gate or the like has a first insulating film 12 made of silicon oxide or the like formed on a transparent insulating substrate 10, and the first insulating film 12 is formed. An active layer 13b made of a polysilicon film or the like is formed on the insulating film 12, and a second insulating film 14 made of silicon oxide or the like is formed on the active layer 13b.
A gate electrode 15b made of conductive polysilicon or the like is formed via b. Thus, the thin film transistor is formed by providing the gate electrode 15b on the active layer 13b with the second insulating film 14b serving as a gate insulating film interposed therebetween.

A third insulating film 16 made of a PSG film or the like is formed on the entire surface of the substrate including the thin film transistor.
Wirings 17b and 17c made of aluminum or the like and connected to the source and drain side active layers 13b of the thin film transistors are formed on the third insulating film 16 through the contact holes formed in the third insulating film 16. There is.

A fourth insulating film 18 made of PSG or the like is formed on the third insulating film 16, and a flattening film 21 made of silicon oxide or the like having a flattened surface is further formed. . The film forming the thin film transistor in the peripheral circuit basically shares the film formed in the pixel portion.

As shown in FIG. 16B, a flattening film 21 is formed on the pixel portion and the peripheral circuit portion, a pixel electrode made of ITO or the like is formed on the pixel portion, and then an alignment film such as polyimide is formed on the pixel portion. After being formed, the alignment film is subjected to a rubbing treatment by the above-mentioned roller or the like.

[0011]

However, the alignment film formed in the pixel portion is rubbed by physically rubbing it with the above-mentioned roller or the like. At this time, the roller is also attached to the substrate in the peripheral portion. Will come into contact.

Then, when the roller rubs the flattening film 21 formed on the substrate in the peripheral portion, static electricity is generated by the friction of the roller, and the static electricity destroys the thin film transistor constituting the peripheral circuit. was there.

That is, since the wiring 17b connected to, for example, the drain of the thin film transistor forming the peripheral circuit is relatively long, it is easy to have a larger electrostatic capacity due to the friction of the roller, and the static electricity accumulated on this wiring 17b is stored in the thin film transistor. When reaching the drain, a high electric field is applied between the drain and the gate electrode of the thin film transistor and between the drain and the source, so that the thin film transistor forming the peripheral circuit is considered to be destroyed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device capable of preventing peripheral circuits from being destroyed by static electricity generated in a rubbing process, and a manufacturing method thereof. Especially.

[0015]

In order to achieve the above-mentioned object, a liquid crystal display device of the present invention has a pixel portion having a thin film transistor as a switching element, and at least a part of the thin film transistor is formed by the thin film transistor. A liquid crystal display device comprising: a substrate partitioned into a peripheral portion having a peripheral circuit for writing a pixel signal, and a liquid crystal layer held by an alignment film formed in at least the pixel portion of the substrate, A conductive shield film for releasing generated static electricity is provided on the peripheral circuit above the peripheral circuit.

The shield film is fixed at a constant potential. The shield film is formed at least in the upper layer of a wiring layer connected to the thin film transistor formed in the peripheral portion.

According to the above-described liquid crystal display device of the present invention, since the conductive shield film for releasing the generated static electricity is formed on the upper layer of the peripheral circuit in the peripheral portion, the liquid crystal layer is held thereon. In the rubbing process of the alignment film,
Static electricity generated by rubbing the peripheral portion of the substrate is accumulated in the shield film. For example, by fixing the shield film at a constant potential, the electricity accumulated in the shield film is removed.

Further, in order to achieve the above object, in the method for manufacturing a liquid crystal display device of the present invention, a pixel portion having a thin film transistor as a switching element and at least a part of the thin film transistor are formed, and a pixel is provided for the pixel portion. A method for manufacturing a liquid crystal display device, comprising a substrate partitioned into a peripheral portion having a peripheral circuit for writing a signal, forming an alignment film on at least the pixel portion of the substrate, and forming a liquid crystal layer on the alignment film. That is, after forming the peripheral circuit, before forming the alignment film, a step of forming a conductive shield film on an upper layer of the peripheral circuit in the peripheral portion, and after forming the alignment film. And a step of subjecting the alignment film to a rubbing treatment.

After the step of performing the rubbing treatment, the method further comprises the step of fixing the shield film at a constant potential to eliminate the electricity accumulated in the shield film during the rubbing treatment.

According to the method of manufacturing a liquid crystal display device of the present invention described above, since the conductive shield film is formed on the peripheral circuit in the peripheral portion, the alignment film for holding the liquid crystal layer thereon. In the rubbing process, static electricity generated by rubbing the peripheral portion of the substrate is accumulated in the shield film. For example, in the subsequent process, the static electricity is accumulated in the shield film by fixing the shield film at a constant potential. Electricity is removed.

In order to achieve the above object, the method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming thin film transistors in a pixel portion and a peripheral portion of a transparent insulating substrate, and the pixel portion of the transparent insulating substrate. And a step of forming a conductive film in the peripheral portion, a step of patterning the conductive film to form a light shielding film that shields the thin film transistor in the pixel portion, and a shield film in the peripheral portion, A step of forming an alignment film on the upper layer of the light-shielding film in at least the pixel portion of the transparent insulating substrate; a step of subjecting the alignment film to a rubbing treatment; a counter substrate having the alignment film formed thereon and the transparent insulating substrate. Facing each other and injecting liquid crystal between the alignment film on the transparent insulating substrate and the alignment film on the counter substrate to seal the liquid crystal.

After the step of injecting and sealing the liquid crystal,
The method further includes the step of fixing the shield film at a constant potential and removing the electricity accumulated in the shield film during the rubbing process.

According to the above-described method of manufacturing the liquid crystal display device of the present invention, the shield film is formed on the upper layer of the peripheral circuit in the peripheral portion by the conductive film forming the light shielding film for shielding the thin film transistor in the pixel portion. In the rubbing process of the alignment film that holds the liquid crystal layer on it, static electricity generated by rubbing the peripheral part of the substrate is accumulated in the shield film. For example, in the subsequent step, the shield film is fixed at a constant potential. By doing so, the electricity accumulated in the shield film is removed.

In order to achieve the above object, the method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming a thin film transistor in a pixel portion and a peripheral portion of a transparent insulating substrate, and the pixel portion of the transparent insulating substrate. A step of forming a light-shielding film on the upper layer of the thin film transistor, a step of forming a transparent conductive film on the pixel portion and the peripheral portion of the transparent insulating substrate, and patterning the transparent conductive film to form a pixel on the pixel portion. Forming a pixel electrode and forming a shield film on the peripheral part; forming an alignment film on the pixel electrode at least in the pixel part of the transparent insulating substrate; and rubbing the alignment film. A step of performing a treatment, the counter substrate on which an alignment film is formed and the transparent insulating substrate are opposed to each other, and the alignment film on the transparent insulating substrate and the alignment on the counter substrate And a step of sealing by injecting liquid crystal between.

After the step of injecting and sealing the liquid crystal,
The method further includes the step of fixing the shield film at a constant potential and removing the electricity accumulated in the shield film during the rubbing process.

According to the method for manufacturing a liquid crystal display device of the present invention, the transparent conductive film forming the pixel electrode in the pixel portion forms a shield film on the upper layer of the peripheral circuit in the peripheral portion, thereby forming the liquid crystal layer. In the rubbing treatment of the alignment film held on it, static electricity generated by rubbing the peripheral part of the substrate is accumulated in the shield film, and for example, by fixing the shield film to a constant potential in the subsequent step. The electricity accumulated in the shield film is removed.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid crystal display device and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration example of a liquid crystal panel 1 of the liquid crystal display device according to the present embodiment. As shown in FIG. 1, the liquid crystal panel 1 includes a horizontal shift register (hereinafter referred to as an H shift register) 2 and a vertical shift register (hereinafter referred to as a V shift register) 3.
An image display section (pixel section) 4 and a horizontal switch section 5.

The H shift register 2 has a function of selecting a column to be driven, and the V shift register 3 has a function of selecting a row to be driven. The pixel section 4 is configured by arranging pixel dots in a matrix, and by applying a signal voltage (video signals Sig1, Sig2, Sig3), the video signals Sig1, Sig2, Sig3 input from a signal driver (not shown) are input. It has a function of selectively supplying to the pixel portion 4.

A start pulse signal VST and a clock pulse signal VCK are input to the V shift register 3 from a timing generator (not shown), and the input of the start pulse signal VST causes the V shift register 3 to move vertically in a time interval determined by the clock pulse signal VCK. The vertical selection pulse is output while being sequentially shifted. The vertical selection pulse drives a pixel transistor 41 which is a switching element of each row in the pixel section 4 described later.

Each dot of the pixel section 4 is composed of a pixel transistor 41 and a liquid crystal cell 42.
To the liquid crystal cell 42 through the video signals Sig1, Sig
Image display is performed by applying 2 and Sig3. As the pixel transistor 41, for example,
A thin film transistor (TFT) is used. Here, the liquid crystal cell 42 includes a pixel electrode connected to the source of the pixel transistor 41, a counter electrode connected to the common potential VCOM, and a liquid crystal layer sandwiched between these electrodes, and has an equivalent capacitance of Cs. Is considered to be a type of capacitor.

The horizontal switch section 5 includes n horizontal switches 5-1 to 5-1 each formed of a transfer gate.
5-4 are included. However, in the figure, the illustration of the horizontal switches 5-5 and thereafter is omitted. Video signals Sig1, Sig2, and Sig3 are supplied to the horizontal switches 5-1 to 5-4 from a timing generator (not shown). Similarly, three horizontal switches receive the video signals Sig1, Sig2, and Sig3, respectively. It is supplied sequentially. The horizontal switches 5-1 to 5-4 are responsive to the horizontal switch drive pulses D and D ′ sequentially supplied from the H shift register 2 at predetermined time intervals to generate the video signals Sig1 and S.
ig2 and Sig3 are output and selectively supplied to the liquid crystal cell 42 via the pixel transistor 41 of each pixel dot. Here, the drive pulse D ′ means an inverted signal of the drive pulse D. The drive pulse D is input to the n-channel of the transfer gate forming the horizontal switch, and the drive pulse D ′ is input to the p-channel of the transfer gate forming the horizontal switch.

As described above, in the liquid crystal panel 1, not only the pixel transistor 41 of the pixel portion 4 but also the peripheral circuit such as a horizontal switch is constituted by the thin film transistor. FIG. 2 shows a plan view of a transfer gate which constitutes one of the horizontal switches of the peripheral circuit.

As shown in FIG. 2, the transfer gates forming the horizontal switch are commonly connected to the wiring 17b in which the drains of the n-channel transistor n-Tr and the p-channel transistor p-Tr, which are TFTs, are made of aluminum or the like. The sources are commonly connected to the wiring 17c made of aluminum or the like. The transfer gate is turned on when a desired voltage is applied to the gate electrodes 15b and 15d of each transistor, and the wiring 17b connected to the drain is formed.
A desired video signal from is supplied to the pixel portion through the wiring 17c.

As shown in FIGS. 1 and 2, since the wiring 17b connected to the drain of this transfer gate is formed so as to surround the periphery of the pixel portion 4,
It is formed relatively longer than other thin film transistors. As shown in FIG. 2, in the present embodiment, for example, the shield film 20b formed by using the light shielding film of the pixel section 4 is provided on the upper layer of the wiring 17b connected to the drain of the transfer gate.

Next, the liquid crystal display device according to this embodiment will be described in more detail with reference to cross-sectional views of the pixel portion 4 and the peripheral circuit portion. 3A is a cross-sectional view of the pixel portion 4, and FIG. 3B is a cross-sectional view taken along the line AA ′ of FIG. It should be noted that FIG. 3B shows an example of FIG.
Although it will be described as a cross-sectional view taken along the line -A ′, other thin film transistors that form the peripheral circuit also have the same cross-sectional structure and are not limited to this.

As shown in FIG. 3, a conductive light-shielding film 11 is formed on the transparent insulating substrate 10 in the pixel section 4. As the material of the transparent insulating substrate 10, for example, a quartz substrate or a non-alkali glass substrate is used. The material of the conductive light-shielding film 11 is, for example, aluminum (A
1), a metal light-shielding film of titanium (Ti), tungsten (W), molybdenum (Mo), or a metal compound film of molybdenum silicide (MoSi), titanium silicide (TiSi), tungsten silicide (WSi), or the like. The conductive light-shielding film 11 is connected to any fixed potential such as the source potential Vss, the counter electrode potential Vcom, and the drain potential Vdd.

The transparent insulating substrate 10 and the conductive light-shielding film 11 in the pixel portion, and the transparent insulating substrate 10 in the peripheral portion.
A first insulating film 12 made of, for example, a silicon oxide film or a silicon nitride film is formed on the upper surface and covers the entire surface.

As shown in FIG. 3A, an active layer 13a made of, for example, a polysilicon film or an amorphous silicon film is formed on the first insulating film 12 above the conductive light-shielding film 11 in the pixel portion. A second insulating film 14a made of a silicon oxide film or a silicon nitride film for covering the upper surface and the side surface of the layer 13a, and a gate line 15a made of, for example, a conductive polysilicon film crossing the second insulating film 14a are formed. ing. That is, the pixel transistor 41 including a TFT having the gate line 15a provided on the active layer 13a via the second insulating film 14a functioning as a gate insulating film is formed. Further, on the first insulating film 12, a silicon electrode 15c serving as an electrode forming a storage capacitor portion (not shown) is formed.

On the other hand, as shown in FIG. 3B, the active layer 13 made of, for example, a polysilicon film or an amorphous silicon film is formed on the first insulating film 12 in the peripheral portion.
b, a second insulating film 14b made of a silicon oxide film or a silicon nitride film for covering the upper surface and side surfaces of the active layer 13b, and a gate electrode 15b made of, for example, a conductive polysilicon film. That is, a TFT in which a gate electrode 15b is provided via a second insulating film 14b functioning as a gate insulating film is formed on the active layer 13b, and the transfer gate shown in FIG. Peripheral circuits are configured.

By covering the pixel portion and the peripheral portion,
A third insulating film 16 made of PSG (Phosphosilicate glass) or the like is formed. The pixel transistor 41 is opened through the contact hole opened in the third insulating film 16.
A wiring (data line) 17a made of aluminum or the like and connected to the source-side active layer 13a is formed on the third insulating film 16.

In addition, wirings 17b and 17c made of aluminum or the like, which are connected to the drain and source side active layers 13b of the thin film transistors in the peripheral portion through the other contact holes formed in the third insulating film 16, are provided as the third wiring. It is formed on the insulating film 16.

The fourth insulating film 1 made of a PSG film or the like is formed on the entire surface of the substrate including the data line 17a and the wirings 17b and 17c.
8 is formed. Further, on the fourth insulating film 18 above the pixel transistor 41 in the pixel portion and on the fourth insulating film 18 above the wiring 17b connected to the active layer 13b on the drain side of the thin film transistor in the peripheral portion, the nitride film is formed. Silicon films 19a and 19b are formed, respectively.

A light shielding film 20a made of a metal such as Ti forming a black matrix is formed on the silicon nitride film 19a covering the pixel transistor 41 in the pixel portion. Then, the shield film 20b made of Ti forming the black matrix of the pixel portion is also formed on the silicon nitride film 19b covering the wiring 17b connected to the active layer 13b on the drain side of the thin film transistor in the peripheral portion. Has been done. Here, the metal light shielding film 20a and the shield film 20b are formed so as to be electrically isolated from each other.

A flattening film 21 made of, for example, silicon oxide and having a flattened surface is formed on the entire surface of the substrate including the light-shielding film 20a and the shield film 20b. Further, on the flattening film 21 in the pixel portion, for example, ITO (In
A transparent pixel electrode 22a made of a dium tin oxide film is formed in a matrix, and an alignment film 23 made of, for example, a polyimide resin is formed on the pixel electrode 22a and the flattening film 21. In a region (not shown), the pixel electrode 22a is electrically connected to the light shielding film 20a via a contact hole.

Pixel transistor 41 on transparent insulating substrate 10
A counter substrate 24 is provided in a sealed state so as to face the surface on which the transparent insulating substrate 10 and the transparent insulating substrate 10 face each other. 25, and an alignment film 26 that has been rubbed. A liquid crystal layer 27 is formed between the alignment film 23 of the transparent insulating substrate 10 and the alignment film 26 of the counter substrate 24. The material of the counter electrode 25 is, for example,
An ITO film is used, and as the material of the counter substrate, for example, a non-alkali glass plate or a quartz substrate is used.

Next, a method of manufacturing the liquid crystal display device shown in FIG. 3 will be described with reference to FIGS. In each figure, (a) is a sectional view corresponding to FIG. 3 (a), and (b) is a sectional view corresponding to FIG. 3 (b).

First, as shown in FIG. 4, after the conductive light-shielding film 11 is formed on the transparent insulating substrate 10 in the pixel portion, the first insulating film made of, for example, a silicon oxide film is formed on the entire surface of the substrate. 12 is formed. Subsequently, for example, a polysilicon film or an amorphous silicon film is formed on the first insulating film 12, and then patterned into a predetermined shape to form the first insulating film 12 above the conductive light-shielding film 11 in the pixel portion. The active layer 13a is formed on the upper surface, and the active layer 13b is formed on the peripheral portion where the thin film transistor is formed.
To form. Then, to cover the active layers 13a and 13b in the pixel portion and the peripheral portion, for example,
Second insulating films 14a and 14b made of silicon oxide or the like are formed.

Next, as shown in FIG. 5, a conductive polysilicon film having impurities introduced therein is deposited on the entire surface of the substrate. Then, the conductive polysilicon film is patterned into a predetermined shape, and the gate line 15a of the pixel transistor crosses the second insulating film 14a of the pixel portion.
Alternatively, the gate electrode 15b of the thin film transistor is formed on the second insulating film 14b in the peripheral portion while forming the silicon electrode 15c forming the storage capacitor portion. Thus, the pixel transistor 41 including the TFT provided with the gate line 15a via the second insulating film 14a functioning as a gate insulating film is formed on the active layer 13a in the pixel portion, and the active layer 13b in the peripheral portion is formed. Then, a thin film transistor in which the gate electrode 15b is provided through the second insulating film 14b which functions as a gate insulating film is formed.

Next, as shown in FIG. 6, after depositing a third insulating film 16 made of, for example, a PSG film on the entire surface of the substrate, the third insulating film 16 and the second insulating film 1 are deposited.
4a and 14b are selectively removed by etching. Thus, a contact hole exposing the active layer 13a on the source side of the pixel transistor 41 is formed, and a contact hole exposing the active layer 13b on the drain and source sides of the thin film transistor in the peripheral portion is formed. Subsequently, after depositing a metal film such as aluminum on the third insulating film 16 on the entire surface of the substrate, it is patterned into a predetermined shape. Thus, in the pixel portion, the data line 17a connected to the source-side active layer 13a of the pixel transistor 41 through the contact hole is formed, and
Wirings 17c and 17d connected to the drain and source side active layers 13b of the thin film transistors through contact holes are formed in the peripheral portion.

Next, as shown in FIG. 7, a fourth insulating film 18 and a silicon nitride film 19 made of, for example, a PSG film are sequentially formed on the entire surface of the substrate, and then heat treatment is performed under predetermined conditions. The hydrogen contained in the PSG film is supplied to the pixel transistor and the active layers 13a and 13b of the thin film transistor in the peripheral portion. Thus, the trap of the polycrystalline grain boundary of the active layer is filled with hydrogen,
The carrier mobility of a and 13b is improved. P here
The fourth insulating film 18 made of SG is used as the active layers 13a, 13
The silicon nitride film 19 functions as a hydrogen supply source for b, and also functions as a cap film that prevents hydrogen from diffusing outward from the fourth insulating film 18 during the hydrogen supply.

Next, as shown in FIG. 8, Ti is formed on the entire surface of the substrate.
After depositing the light-shielding material 20 such as shown in FIG. 9, the light-shielding material 20 and the silicon nitride film 19 are continuously etched using the resist film patterned into a predetermined shape (not shown) as a mask, and the light-shielding material 20 is then etched. And the silicon nitride film 19 are patterned into the same shape. Thus, the light-shielding film 20a forming the black matrix that covers the pixel transistor 41 and the gate line 15a in the pixel portion is formed on the silicon nitride film 19a. At the same time, a shield film 20b that covers the wiring 17b connected to the drain of the thin film transistor in the peripheral portion is formed on the silicon nitride film 19b while being electrically isolated from the light shielding film 20a. As described above, the present embodiment is characterized in that the shield film 20b that covers the wiring 17b connected to the drain of the thin film transistor in the peripheral portion is formed when the light-shielding material forming the black matrix is patterned.

Next, as shown in FIG. 10, after depositing an insulating film made of, for example, silicon oxide on the entire surface of the substrate, the surface of this insulating film is flattened to form a flattening film 21. Then, after forming a contact hole reaching the light shielding film 20a in a region not shown in the flattening film 21, a transparent pixel electrode 22a made of, for example, an ITO film electrically connected to the light shielding film 20a through the contact hole. Are patterned into a matrix.

Next, after dicing the transparent insulating substrate 10, as shown in FIG. 11, the planarizing film 21 in the pixel portion is formed.
An alignment film 23 made of polyimide or the like is formed on the pixel electrode 22a by a printing method. Then, this alignment film 23
Above, the roller around which a rubbing cloth such as felt or cotton is wound is rotated, and the transparent insulating substrate 10 placed on the table is moved in a direction reverse to the roller rotation direction while keeping contact with the roller.

In this rubbing process, the roller also comes into contact with the flattening film 21 in the peripheral portion of the transparent insulating substrate 10, and static electricity generated by the roller rubbing the flattening film 21 accumulates in the shield film 20b. Will be done. In this way, the alignment film 23 in the pixel portion is
By stretching the alignment film by rubbing, the long axis directions of the molecules of the alignment film are uniformly aligned.

In the subsequent steps, a transparent counter electrode 25 made of, for example, ITO for taking a common potential is formed on the surface, an alignment film 25 is formed on the counter electrode 25, and a rubbing treatment is performed. , A transparent counter substrate 24 made of a non-alkali glass substrate or a quartz substrate,
The transparent insulating substrate 10 is opposed to the surface on which the pixel transistors 41 and the like are formed and sealed.

Subsequently, the alignment film 23 on the transparent insulating substrate 10 is formed.
A liquid crystal is injected between the substrate and the alignment film 26 on the counter substrate 24 and then sealed to form a liquid crystal layer 27. In the injected liquid crystal, the liquid crystal molecules have a predetermined alignment state due to the effect that the long axis directions of the liquid crystal molecules and the alignment film molecules are aligned and are in an energy stable state.

After that, the shield film 20b is fixed to, for example, the ground potential (GND) to eliminate the electricity accumulated in the shield film 20b in the previous rubbing process.
The accumulated electricity may be removed by fixing the shield film 20b to the power supply potential. In this way
The transmissive liquid crystal display device shown in FIGS. 1 to 3 is manufactured.

As described above, in this embodiment, when the light shielding material 20 forming the black matrix is patterned, the shield film 20b for covering the wiring 17b connected to the drain of the thin film transistor in the peripheral portion is formed. In the rubbing process, even when the roller comes into contact with the flattening film 21 in the peripheral portion of the transparent insulating substrate 10 and the roller rubs the flattening film 21, static electricity is generated in the shield film 20b. It is prevented from being accumulated and accumulated in the wiring 17b connected to the thin film transistor of the peripheral circuit. Then, after that, by fixing the shield film 20b to the ground potential or the like, the electricity accumulated in the shield film 20b by the previous rubbing treatment is eliminated.

Therefore, by forming the above-mentioned shield film 20b in the upper layer of the wiring which is connected to the thin film transistors forming the peripheral circuit, particularly the relatively long wiring, the static electricity generated during the rubbing process causes It is possible to prevent the thin film transistors forming the peripheral circuit from being destroyed.

Second Embodiment FIG. 12A is a sectional view of a pixel portion of a liquid crystal display device according to this embodiment, and FIG. 12B is a sectional view taken along line A- of FIG.
It is sectional drawing in the A'line. In addition, FIG.
Similar to the first embodiment, a cross-sectional view taken along the line AA ′ of FIG. 2 will be described as an example, but other thin film transistors that form the peripheral circuit also have the same cross-sectional configuration and are not limited to this. . Further, FIG. 1 of the first embodiment described above.
The same components as those of the liquid crystal display device in FIG. 11 are designated by the same reference numerals and the description thereof will be omitted.

In the first embodiment, the wiring 17b connected to the drain of the thin film transistor in the peripheral portion is formed by the light shielding material forming the black matrix in the pixel portion.
However, in the present embodiment, as shown in FIG. 12, the ITO film forming the pixel electrode 22a in the pixel portion forms the wiring 17b connected to the drain of the thin film transistor in the peripheral portion. A shield film 22b for covering is formed on the flattening film 21.

In the peripheral portion, the shield film 20 formed on the fourth insulating film 18 in the first embodiment.
b, and the silicon nitride film 1 under the shield film 20b.
9b is not formed.

Next, a method of manufacturing the liquid crystal display device shown in FIG. 12 will be described with reference to FIGS.
In each drawing, (a) is a sectional view corresponding to FIG. 12 (a), and (b) is a sectional view corresponding to FIG. 12 (b).

First, after the steps similar to the steps shown in FIGS. 4 to 8 of the first embodiment, the following steps are performed. That is, after depositing a light-shielding material 20 such as Ti on the entire surface of the substrate, as shown in FIG. 13, the light-shielding material 20 and the silicon nitride film 19 are continuously etched using a resist film patterned into a predetermined shape (not shown) as a mask. Then, the light shielding material 20 and the silicon nitride film 19 are patterned into the same shape. In this way, the light-shielding film 20a forming the black matrix that covers the pixel transistor 41 and the gate line 15a in the pixel portion is formed on the silicon nitride film 19a. At this time, in the peripheral portion, the entire surface is etched without leaving the light shielding material 20, and as a result, the silicon nitride film 19 is also entirely removed in the peripheral portion.

Next, as shown in FIG. 14, after an insulating film made of, for example, silicon oxide is deposited on the entire surface of the substrate, the surface of the insulating film is flattened to form a flattening film 21. Subsequently, a transparent electrode material such as an ITO film is deposited on the entire surface of the substrate, and then the transparent electrode material is etched using the resist film patterned into a predetermined shape as a mask. Thus, in the pixel portion, the pixel electrode 22a is formed on the flattening film 21 with the transparent electrode material. At the same time, a shield film 22b made of a transparent electrode material that covers the wiring 17b connected to the drain of the thin film transistor in the peripheral portion is formed on the flattening film 21 while being electrically isolated from the pixel electrode 22a. . As described above, when the transparent electrode material forming the pixel electrode 22a is patterned in the pixel portion, the transparent electrode material is left so as to cover the wiring 17b connected to the drain of the thin film transistor in the peripheral portion. This embodiment is characterized in that

Next, after dicing the transparent insulating substrate 10, as shown in FIG. 15, the flattening film 21 in the pixel portion is formed.
An alignment film 23 made of polyimide or the like is formed on the pixel electrode 22a by a printing method. Then, this alignment film 23
Above, the roller around which a rubbing cloth such as felt or cotton is wound is rotated, and the transparent insulating substrate 10 placed on the table is moved in a direction reverse to the roller rotation direction while keeping contact with the roller.

In this rubbing process, the flattening film 21 and the shield film 2 in the peripheral portion of the transparent insulating substrate 10 are formed.
The roller also comes into contact with 2b, and static electricity generated by the roller rubbing the flattening film 21 and the like is accumulated in the shield film 22b. In this way, the alignment film 23 in the pixel portion has the long axis direction of the alignment film molecules aligned uniformly by stretching the alignment film by rubbing.

In the subsequent steps, as in the first embodiment, a transparent counter electrode 25 made of, for example, ITO for taking a common potential is formed on the surface, and the counter electrode 2 is formed.
An alignment film 25 is formed on the substrate 5 and subjected to a rubbing treatment, and a transparent counter substrate 24 made of, for example, a non-alkali glass substrate or a quartz substrate is made to face the surface of the transparent insulating substrate 10 on which the pixel transistors 41 and the like are formed. And seal.

Subsequently, the alignment film 23 on the transparent insulating substrate 10 is formed.
A liquid crystal is injected between the substrate and the alignment film 26 on the counter substrate 24 and then sealed to form a liquid crystal layer 27. In the injected liquid crystal, the liquid crystal molecules have a predetermined alignment state due to the effect that the long axis directions of the liquid crystal molecules and the alignment film molecules are aligned and are in an energy stable state.

After that, the shield film 22b is fixed to, for example, the ground potential (GND) to eliminate the electricity accumulated in the shield film 22b in the previous rubbing process.
The accumulated electricity may be removed by fixing the shield film 22b to the power supply potential. As described above, the transmissive liquid crystal display device shown in FIG. 12 is manufactured.

As described above, in this embodiment, when patterning the transparent electrode material forming the pixel electrode, the wiring 17b connected to the drain of the thin film transistor in the peripheral portion.
By forming the shield film 22b covering the above, the roller also comes into contact with the flattening film 21 and the shield film 22b in the peripheral portion of the transparent insulating substrate 10 in the rubbing process, and the flattening film 21 and the shield film 22b are removed. Even if static electricity is generated by rubbing the roller, the static electricity is prevented from being accumulated in the shield film 22b and accumulated in the wiring 17b connected to the thin film transistor of the peripheral circuit. Then, after that, the shield film 2
By fixing 2b to the ground potential or the like, the electricity accumulated in the shield film 22b by the previous rubbing treatment is eliminated.

Therefore, by forming the above-mentioned shield film 22b in the upper layer of the relatively long wiring among the wirings connected to the thin film transistors forming the peripheral circuit, the static electricity generated during the rubbing process causes It is possible to prevent the thin film transistors forming the peripheral circuit from being destroyed.

The present invention is not limited to the above description of the embodiments. For example, in the present embodiment, an example in which the shield film is formed in the upper layer of the wiring connected to the drain of the transfer gate forming the horizontal switch among the thin film transistors forming the peripheral circuit has been described as an example. However, the same effect can be obtained by forming a shield film in the upper layer of a relatively long wiring connected to the thin film transistor that constitutes the peripheral circuit.

Further, for example, in the present embodiment, at the same time as the process of forming the light-shielding film and the pixel electrode of the pixel portion, the shield film is formed by the light-shielding material forming the light-shielding film and the transparent electrode material forming the pixel electrode. However, the present invention is not limited to this. For example, in the subsequent steps of forming the thin film transistor in the pixel portion and the peripheral portion, if there is a process using a conductive material, when patterning it in the same manner, Although it can be used as a material for the shield film and the number of steps is increased, the shield film may be formed in another step.

Further, in the present embodiment, the transmissive liquid crystal display device has been described as an example, but the present invention is not limited to this, and is similarly applied to a manufacturing method of a reflective liquid crystal display device. You can Besides, various modifications can be made without departing from the scope of the present invention.

[0077]

According to the present invention, it is possible to prevent the peripheral circuits from being destroyed by the static electricity generated in the rubbing process.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a liquid crystal panel of a liquid crystal display device according to an embodiment.

FIG. 2 is a plan view of a transfer gate that constitutes one of horizontal switches of a peripheral circuit.

3A is a sectional view of a pixel portion of the liquid crystal display device according to the first embodiment, and FIG. 3B is a sectional view of FIG.
It is sectional drawing in the -A 'line.

FIG. 4 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the first and second embodiments, showing the state after the formation of the active layer.

FIG. 5 is a process cross-sectional view for explaining the manufacturing method of the liquid crystal display device according to the first and second embodiments, showing a state after the gate electrode is formed.

FIG. 6 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the first and second embodiments, showing the state after the wiring is formed.

FIG. 7 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the first and second embodiments, showing the state after the formation of the silicon nitride film.

FIG. 8 is a process cross-sectional view for explaining the manufacturing method of the liquid crystal display device according to the first and second embodiments, showing a state after the deposition of the light shielding material.

FIG. 9 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the first embodiment, showing a state after the light-shielding film and the shield film have been formed.

FIG. 10 is a process cross-sectional view for explaining the manufacturing method of the liquid crystal display device according to the first embodiment, showing a state after the pixel electrode is formed.

FIG. 11 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the first embodiment, showing a state after the formation of the alignment film.

12A is a sectional view of a pixel portion of a liquid crystal display device according to a second embodiment, and FIG. 12B is a sectional view taken along the line AA ′ of FIG.

FIG. 13 is a process cross-sectional view for explaining the manufacturing method of the liquid crystal display device according to the second embodiment, which shows a state after the formation of the light shielding film.

FIG. 14 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the second embodiment, showing the state after the pixel electrode and the shield film are formed.

FIG. 15 is a process cross-sectional view for explaining the method for manufacturing the liquid crystal display device according to the second embodiment, showing the state after the formation of the alignment film.

FIG. 16 is a diagram for explaining a problem in manufacturing a conventional liquid crystal display device.

[Explanation of symbols]

1 ... Liquid crystal panel, 2 ... H shift register, 3 ... V shift register, 4 ... Pixel part, 5 ... Horizontal switch part, 5-1
5-2, 5-3, 5-4 ... Horizontal switch, 10 ... Transparent insulating substrate, 11 ... Conductive light-shielding film, 12 ... First insulating film, 1
3a, 13b ... Active layer, 14a, 14b ... Second insulating film, 15a ... Gate wiring, 15b, 15d ... Gate electrode, 15c ... Silicon electrode, 16 ... Third insulating film, 17
a ... Data line, 17b, 17c ... Wiring, 18 ... Fourth insulating film, 19a, 19b ... Silicon nitride film, 20a ... Light shielding film, 20b ... Shield film, 21 ... Flattening film, 22a ... Pixel electrode, 22b ... Shield film, 23 ... Alignment film, 24 ... Counter substrate, 25 ... Counter electrode, 26 ... Alignment film, 27 ... Liquid crystal layer, 41 ... Pixel transistor, 42 ... Liquid crystal cell, nT
r ... n-channel transistor, p-Tr ... p-channel transistor.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/30 338 G09F 9/30 338 5F110 9/35 9/35 5G435 H01L 29/786 H01L 29/78 623A F term ( reference) 2H089 LA24 NA24 QA16 TA04 TA09 TA13 2H090 HB03X HB08Y JB02 LA04 LA05 MB01 MB03 2H091 FC07 GA01 GA06 GA13 LA07 2H092 GA29 JA24 JA41 JA46 JB58 KA04 KA05 NA14 PA01 PA02 PA09 5C094 AA25 AA42 AA43 AA48 BA03 BA43 CA19 DA09 DA13 DB01 DB04 EA04 EA05 EA10 ED15 FA01 FA02 FB12 FB14 FB15 5F110 AA22 BB02 BB04 CC02 DD02 DD03 DD13 DD14 EE09 FF02 FF03 GG02 GG13 GG15 HL03 NN03 NN24 NN25 NN44 NN45 NN46 NN46 NN46 NN72 NN72 NN72 QQ19 QQ23 5G435 AA14 A16

Claims (9)

[Claims] 1. A substrate including a pixel portion having a thin film transistor as a switching element and a peripheral portion at least a part of which is formed of the thin film transistor and having a peripheral circuit for writing a pixel signal to the pixel portion.
A liquid crystal display device in which a liquid crystal layer is held via an alignment film formed in at least the pixel portion of the substrate, wherein a conductive shield film for discharging generated static electricity is provided in an upper layer of the peripheral circuit in the peripheral portion. A liquid crystal display device having. 2. The liquid crystal display device according to claim 1, wherein the shield film is fixed at a constant potential. 3. The liquid crystal display device according to claim 1, wherein the shield film is formed at least in an upper layer of a wiring layer connected to the thin film transistor formed in the peripheral portion. 4. A substrate which is partitioned into a pixel portion having a thin film transistor as a switching element and a peripheral portion having at least a part formed of the thin film transistor and having a peripheral circuit for writing a pixel signal to the pixel portion,
An alignment film is formed on at least the pixel portion of the substrate,
A method of manufacturing a liquid crystal display device, comprising forming a liquid crystal layer on the alignment film, comprising: forming a conductive film on the peripheral circuit upper layer in the peripheral portion after forming the peripheral circuit and before forming the alignment film. 2. A method of manufacturing a liquid crystal display device, comprising: the step of forming the shield film of 1 .; and the step of subjecting the alignment film to a rubbing treatment after forming the alignment film. 5. The method according to claim 4, further comprising a step of fixing the shield film at a constant potential after the step of performing the rubbing process to eliminate the electricity accumulated in the shield film during the rubbing process. Liquid crystal display device manufacturing method. 6. A step of forming a thin film transistor in a pixel portion and a peripheral portion of a transparent insulating substrate; a step of forming a conductive film in the pixel portion and the peripheral portion of the transparent insulating substrate; and patterning the conductive film. A light-shielding film that shields the thin film transistor in the pixel portion, and
A step of forming a shield film on the peripheral portion, a step of forming an alignment film on the light shielding film in at least the pixel portion of the transparent insulating substrate, a step of subjecting the alignment film to a rubbing treatment, and an alignment film And a liquid crystal is injected between the alignment film on the transparent insulating substrate and the alignment film on the counter substrate to seal the liquid crystal. Manufacturing method of display device. 7. After the step of injecting and sealing the liquid crystal,
7. The method for manufacturing a liquid crystal display device according to claim 6, further comprising a step of fixing the shield film at a constant potential to remove electricity accumulated in the shield film during the rubbing treatment. 8. A step of forming a thin film transistor in a pixel portion and a peripheral portion of a transparent insulating substrate; a step of forming a light shielding film on an upper layer of the thin film transistor in the pixel portion of the transparent insulating substrate; A step of forming a transparent conductive film on the pixel portion and the peripheral portion, and a step of patterning the transparent conductive film to form a pixel electrode on the pixel portion and a shield film on the peripheral portion. A step of forming an alignment film on at least an upper layer of the pixel electrode in the pixel portion of the transparent insulating substrate; a step of subjecting the alignment film to a rubbing treatment; and a counter substrate having the alignment film formed thereon and the transparent insulating substrate. And a liquid crystal is injected between the alignment film on the transparent insulating substrate and the alignment film on the counter substrate to seal the liquid crystal display device. Method. 9. After the step of injecting and sealing the liquid crystal,
9. The method of manufacturing a liquid crystal display device according to claim 8, further comprising a step of fixing the shield film at a constant potential to remove electricity accumulated in the shield film during the rubbing process.