JPH11109378A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the peeling of Al in the adhesiveness between Si nitrided films and planarization films, to improve a yield and to suppress a change with lapse of time by disposing sealing materials on the corresponding planarization films between the first transparent substrate sides and driver circuits. SOLUTION: The planarization films are applied on the uppermost surface formed with the driver circuits 16 to 18 and are cured. On the other hand, the surface of a second transparent substrate is provided with counter electrodes consisting of ITO. The first transparent substrate and the second transparent substrate are respectively provided with alignment layers and the respective transparent substrates are arranged to face each other and are provided with the sealing materials for sealing liquid crystals therebetween. The liquid crystals are injected via injection holes composed of part of the sealing materials, by which the liquid crystal display device is obtd. In such a case, the sealing materials 73 are applied between the driver circuits and the lateral sides of the liquid crystal display device evading the driver circuits. When the planarization films are formed in such a manner, the films have the good adhesiveness to the Si nitride films and, therefore, both sides of the Al are so formed as to hold down the wiring over the entire area with these adhesive surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which a problem mainly caused by a sealing material is prevented.

[0002]

2. Description of the Related Art In recent years, attention has been paid to low power consumption, thin and lightweight, high-definition images, etc. of liquid crystal display devices, and liquid crystal display devices employing TFTs have been actively studied. In particular, a-S
i and poly-Si are mainly used, but poly-Si has recently attracted attention from the viewpoints of mobility, aperture ratio, number of process steps and the like, and has been put to practical use.

[0005] For example, FIG. 5 is a schematic plan view of a liquid crystal display device. A plurality of wirings extending left and right are gate lines 10, and a plurality of wirings extending vertically are drain lines 11. is there. The gate lines 10 and the drain lines 11 form intersections in a matrix, and the display electrodes 12 and the TFTs 13 electrically connected to the display electrodes 12 form a pair to form a display area. .

On the other hand, the glass substrate 14 on which these are formed is
Terminals 15 are arranged in groups on one side, and a driver circuit for driving the liquid crystal display device, here, a precharge driver 16 is formed between the terminal groups 15 and the display area. The drain driver 17 is formed on the opposite side. Further, gate drivers 18 are formed on the left and right sides.

The gate driver 18 has wirings 19, 2 for inputting a vertical clock signal and a vertical start signal.
0 is a line to which a horizontal clock signal, a horizontal start signal and a video signal are inputted to the drain driver 17, a line to which a precharge signal and a gate control signal are inputted to the precharge driver 16. 24 and 25 extend around the substrate 14 and are connected to the terminals 15. Although other terminals are provided, the description is omitted here.

FIG. 6 is a sectional view of one pixel in the display area. Non-alkali glass 50 as the first transparent substrate
(Corresponding to reference numeral 14 in FIG. 5), on which a gate 51 of the transistor and a gate line integral therewith are formed, and an auxiliary capacitance electrode 52 of the same material is formed.
Are formed. Here, Cr is adopted in consideration of corrosion resistance and resistance value, and a tapered structure is adopted in consideration of film breakage on this.

On the entire surface, Si is formed by plasma CVD.
An oxide film 53 and a Si nitride film 54 are formed, and a poly-Si 55 patterned to extend to the transistor region and the auxiliary capacitance region is provided. Here, an impurity P is introduced into the poly-Si, and the low concentration N− type source / drain regions 57 and 58 and the high concentration N + type contact region 5 are formed.
9, 60 are formed. The channel region 56 of the transistor is provided with a mask 61 made of a Si oxide film in order to prevent this impurity.

The auxiliary capacitance is a poly-Si N + type contact region 6 extending to the auxiliary capacitance electrode 52.
0, an auxiliary capacitance electrode 52 made of Cr and an insulating layer 53,
54. Furthermore, plasma CVD is performed on the entire surface.
The Si oxide film 62 and the Si nitride film 63 are covered by the method,
A contact hole is formed by partially opening the contact region 59, and an Al drain electrode 64 is provided.
A flattening film 65 is formed on the entire surface to fill the unevenness of the conventional structure, and a display electrode 66 made of ITO is formed through a contact hole in which a part of the contact region 60 is exposed.
Is provided.

The driver circuits 16, 1 shown in FIG.
Each of the components 7 and 18 is composed of, for example, a bottom gate transistor, a resistor made of poly-Si, a wiring, and the like, utilizing the components shown in FIG. The bottom gate transistor and the transistor formed in the pixel are formed in substantially the same process, and the resistor is made of poly-Si which is a semiconductor layer of the transistor.
55 is formed by introducing an impurity, and the wiring is formed by the Al electrode of the drain electrode 64. The intersection of the wirings is formed by utilizing the Cr of the gate. To insulate them, insulating layers 53 and 54 formed between the gate 51 and the semiconductor layer and insulating layers 62 and 63 formed on the semiconductor layer are mainly used. Therefore, the flattening film 65 is applied and hardened on the uppermost surface on which the driver circuit is formed.

On the other hand, on the second transparent substrate 70, an IT
A counter electrode 67 made of O is provided. In addition, here, for color display, an RGB color filter 6 is used.
8 is provided in a region corresponding to the display electrode 66, and a light shielding film 69 is provided therearound. If necessary, it may be provided before the counter electrode 67 is provided to flatten the unevenness.

The transparent substrates 50 and 70 having the above-described structure are provided with alignment films 71 and 72, and the transparent substrates are arranged to face each other. Thereafter, a sealing material 73 is provided as shown in FIG. 7 in order to fill the liquid crystal during this time. Liquid crystal is injected through an injection hole 74 which is a part of the sealing material, and a sealing material 76 is applied to complete the liquid crystal display device.

FIG. 7 explains the position of the sealing material in FIG. 5, and the area indicated by the dashed line is the display area 7 described above.
7

[0013]

In this configuration, as can be seen from FIG. 5, the seal member 73 overlaps the driver circuits 16, 17, and 18. Considering the cross section, a transistor of a driver circuit is also formed like the TFT of FIG. 6, and after an insulating layer of the same material as the Si nitride film 63 is covered, a driver transistor formed of Al as a drain electrode material is formed. Source and drain electrodes and wirings 19 to 23 are formed, and a planarizing film 65 is further formed thereon.
Are formed.

Although the adhesion between the Si nitride film and the acrylic resin as the flattening film is good, the acrylic resin and A
1 is poor in adhesion. In addition, the acrylic resin and the sealant are made of the same polymer material, and thus have good adhesiveness. Therefore, if the Al wiring and the Al electrode are vertically and horizontally inclined and the sealing material 73 is provided on a driver circuit formed very densely like a spider web, the sealing material and the acrylic material are shrunk when the sealing material is cured. Since the adhesiveness of the resin is good, the interfaces between the acrylic resin and the Al wiring and between the acrylic resin and the Al electrode are peeled off.
l causes distortion and disconnection, eventually resulting in transistor deterioration,
There was a problem that led to failure.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and firstly, the sealing is provided on the flattening film corresponding to between the driver circuit and the first transparent substrate side. This can be solved by providing a material. Original wiring 19
It is sufficient to provide a sealing material in a portion having no ２３23, but there is a problem that the size of the glass substrate becomes large. However, the Al wiring between the region where the drive circuit is formed and the side of the transparent substrate is formed in a certain direction, and the Si nitride films are exposed on both sides in the same direction. That is, they are formed more sparsely than the Al wirings and electrodes of the driver circuit. Therefore, if a sealing material is provided in this portion, Si nitride films having good adhesion to the flattening film exist on both sides of the Al wiring, and the adhesiveness between the Si nitride film and the flattening film on both sides of the Al wiring is present. Can prevent the peeling of Al.

Second, the problem is solved by providing dummy wirings so as to be substantially equal to the maximum number of wirings included in the sealing material. If the distance between the Al wirings is a predetermined distance and the ratio of the width of the exposed Si nitride film to the width of the Al wiring is approximately 1 or more as described later, peeling of the Al wiring can be prevented. Width of the flattening film,
Since the amount of the spacer provided on the bulge varies between the sides of the sealing material and the four sides of the sealing material, the gap is not uniform. However, the gap can be solved by providing a dummy pattern.

In particular, if the dummy wiring is provided so as to have the total width of the actual wiring located under the sealing material, the gap can be made more uniform for the above-mentioned reason.

[0018]

Embodiments of the present invention will be described below. First, although described in the conventional example, the planar arrangement will be described again with reference to FIG. A plurality of wirings extending left and right are gate lines 10 made of Cr, and a plurality of wirings extending vertically are drain lines 11 made of Al. And two kinds of lines 10,
11 form an intersection in the form of a matrix, in which a display electrode 12 made of ITO,
And the TFTs 13 electrically connected to each other constitute a display region.

On the other hand, the glass substrate 14 on which these are formed
Terminals 15 are arranged in groups on one side, and a driver circuit for driving the liquid crystal display device, here, a precharge driver 16 is formed between the terminal groups 15 and the display area. The drain driver 17 is formed on the opposite side. Further, gate drivers 18 are formed on the left and right sides. However, the positions of the drain driver and the precharge driver may be exchanged, or the gate driver may be formed on one side.

The gate driver 18 has an Al wiring 1 to which a vertical clock signal and a vertical start signal are input.
9 and 20, a drain driver 17 receives a horizontal clock signal, a horizontal start signal, and a video signal. Al wirings 21, 22, and 23 receive a precharge signal and a gate control signal. Al wirings 24 and 25 are connected to the terminal 15 while rotating around the substrate 14.

Next, the sectional structure of the pixel portion will be described.
Alkali-free glass 50 (corresponding to reference numeral 14 in FIG. 1) is employed as a first transparent substrate, on which a transistor gate 51 and a gate line 10 integrated therewith are provided.
Are formed, and an auxiliary capacitance electrode 52 of the same material is formed. Here, Cr is adopted in consideration of corrosion resistance and resistance value, and a tapered structure is adopted in consideration of film breakage on this.

On the entire surface, Si is formed by plasma CVD.
An oxide film 53 and a Si nitride film 54 are formed, and a poly-Si 55 patterned to extend to the transistor region and the auxiliary capacitance region is provided. Here, an impurity P is introduced into the poly-Si, and the low concentration N− type source / drain regions 57 and 58 and the high concentration N + type contact region 5 are formed.
9, 60 are formed. The channel region 56 of the transistor is provided with a mask 61 made of a Si oxide film in order to prevent this impurity.

The auxiliary capacitance is a poly-Si N + type contact region 6 extending to the auxiliary capacitance electrode 52.
0, an auxiliary capacitance electrode 52 made of Cr and an insulating layer 53,
54. Furthermore, plasma CVD is performed on the entire surface.
The Si oxide film 62 and the Si nitride film 63 are covered by the method,
A contact hole is formed by partially opening the contact region 59, and an Al drain electrode 64 is provided.
Further, a flattening film 65 made of an acrylic resin that fills the irregularities formed in the conventional configuration is provided on the entire surface, and the IT region is exposed through a contact hole in which a part of the contact region 60 is exposed.
A display electrode 66 made of O is provided.

The driver circuits 16, 1 in FIG.
Each of the components 7 and 18 is composed of, for example, a bottom gate transistor, a resistor made of poly-Si, a wiring, and the like, utilizing the components shown in FIG. The bottom gate transistor and the transistor formed in the pixel are formed in substantially the same process, and the resistor is made of poly-Si which is a semiconductor layer of the transistor.
The source and drain electrodes of the wiring and the driver circuit transistor are formed by the Al electrode of the drain electrode 64. The intersection of the wirings is formed by utilizing the Cr of the gate. To insulate them, insulating layers 53 and 54 formed between the gate 51 and the semiconductor layer and insulating layers 62 and 63 formed on the semiconductor layer are mainly used.

Therefore, the flattening film 65 is applied and hardened on the uppermost surface on which the driver circuit is formed.
On the other hand, a counter electrode 67 made of ITO is provided on the second transparent substrate 70. Further, here, for color display, an R, G, B color filter 68 is provided in a region corresponding to the display electrode 66, and a light shielding film 69 is provided therearound. If necessary, a flattening film may be provided before the counter electrode 67 is provided to flatten the unevenness.

The first transparent substrate 50 and the second transparent substrate 70 having the above-described structures are provided with alignment films 71 and 72, and the transparent substrates are arranged to face each other. A sealing material is provided, and liquid crystal is injected through an injection hole formed as a part of the sealing material, thereby completing the liquid crystal display device. The feature here is that, like the sealing material 73 shown in FIG. 1, the coating is applied between the driver circuit and the side of the liquid crystal display device, avoiding the driver circuit.

The driver circuits 16 to 18 are made of wiring made of Al, that is, the source of a transistor formed here.
The drain electrode is formed in a spider web shape vertically and horizontally or diagonally, and the amount of the Si nitride film exposed between Al is very small, but the driver circuit on which the wirings 18 to 23 are formed and the side of the liquid crystal display device Between the sides, Al wiring is sparse, and S
The i-nitride film is formed widely.

In particular, in this region, the wiring is arranged in parallel with the side of the liquid crystal display device, and on both sides of this wiring, a Si nitride film is exposed as an adhesive. That is, when the flattening film is formed thereon, since the adhesiveness with the Si nitride film is good, both sides of Al are formed so as to press down the wiring over the entire area with this bonding surface.
Therefore, even if the sealing material 73 is applied to this area, peeling of the Al wiring is prevented.

Further, a number of wirings having a width of 22 μm were formed under the sealing material, and the pitch was changed to examine the releasability of the wirings. As a result, it was found that if the ratio of the width of the Al wiring to the width of the exposed Si nitride film was 1 or less, it was easy to peel off. That is, if the ratio of the exposed width of the Si nitride film exceeds 1, the peeling is suppressed. Subsequently, referring to FIG.
A brief description will be given of a method of applying the composition. What is represented here is the first transparent substrate 14 (or reference numeral 50) or the second transparent substrate 14.
Is a large plate formed in a matrix. The sealing material may be applied to either of the substrates, but is formed on a large plate having at least the first transparent plates 14a, 14b, 14c, and 14d in the drawing. Generally, the liquid crystal is formed by dividing a liquid crystal formed in a matrix, such as taking four sheets from a large plate.

That is, the large plate formed up to the alignment film is successively formed on the individual first transparent substrates 14a, 14b, 14c, 14c.
A sealing material is applied so as to surround d. And 7
As in the injection hole 4, an entrance into which the liquid crystal partially enters is formed. Then, the large plate of the first transparent substrate and the large plate on the second transparent substrate side are bonded to each other, and thereafter, a streak of the scribe line SR is formed on the back surfaces of both large plates by using a scriber such as a diamond cutter. You. Then, the liquid crystal display device is divided along the scribe line SR and before the liquid crystal is injected. Finally, the liquid crystal is injected through the injection hole 74, the sealing resin 76 is applied, and the liquid crystal is completed.

Conventionally, as shown in FIG.
Was terminated short of the side of the glass substrate. However, in this case, since the gap of the liquid crystal display device is narrow, even if the sealing resin 76 is applied, poor adhesion between the sealing material 73 and the sealing material 76 has occurred. Therefore, as shown in FIG. 2, the end portion 75 is made to protrude significantly. In this case, if the end portion 75 is divided along the scribe line SR, the tip end portion 75 of the sealing material divided at the time of division remains on the substrate 14 d. It becomes a problem in the appearance, and, at the time of division, fine glass dust remains together with the sealing material, and further, since the sealing material intersects the scribe line SR, it is separated from the scribe line and divided. A problem arose.

Therefore, since the sealing material 73 is applied with a dispenser, attention is paid to the fact that the tip 75 has a tapered shape, and this tapered portion passes through the scribe line SR as shown in FIG. Was applied as follows. Actually, the taper starts before the scribe line SR, and the length of the point passing from the scribe line SR is substantially 1 to 5
0 μm.

With such a structure, the adhesiveness between the front end portion 75 and the substrate 14d is weakened. Therefore, when divided along the scribe line SR, the sealing material 73
And will remain as one. Therefore, as shown in FIG. 1, the sealing material is provided so as to slightly protrude from the side of the liquid crystal display device. Therefore, even if the sealing material 76 is applied, the sealing material contacts the sealing material. Good adhesion. Further, the amount is such that the tip end portion 75 is cut off and cannot be seen even if it adheres to the substrate 14d, and no problem occurs.

On the other hand, in order to determine the gap between the first transparent substrate and the second transparent substrate, a spacer (glass fiber) smaller in diameter than the spacers scattered in the display area is mixed into the sealing material. I have. The wiring DH shown in FIG.
Is ignored, the left side of the sealing material on the lower side of FIG.
The main side is arranged, but the other side is one or not arranged at all. Further, a flattening film is provided on the wiring, and the swelling width of the flattening film is different depending on the number of wirings, so that the number of spacers disposed thereon is also different.
Therefore, when the sealing material is fixed, both transparent substrates are pressed and fixed, but since the gap defined by the spacer varies over the entire side and between the sides, the spacer is pressed by the pressure at the time of bonding. However, there has been a problem that sunk in the flattening film or unevenness of the swelling width of the flattening film occurs, and the gap cannot be made uniform over the entire area.

In the present invention, dummy wirings are provided like DH1 to DH3. In the present application, since a maximum of two actual wirings are provided under the seal, the entire area is provided to be two including the dummy wirings. First, Figure 1
Considering the lower side, only the wiring 19 is provided from the terminal to the point P under the sealing material. Therefore, DH3 is provided.

Since no wiring is arranged on the right side, DH2 and DH3 are provided. Further, DH1 and DH4 are provided on the upper side, and DH4 is provided on the left side. In other words, since two actual wires for transmitting signals are provided on the left side of the lower side,
Since no wiring is provided, a dummy wiring is provided, and the step width of the flattening film provided thereon and the number of spacers scattered thereon are made substantially the same, so that the gap is equal over four sides. Dummy wiring is provided so that Therefore, the width of the raised portion (concavo-convex portion) of the flattening film including the dummy wiring is substantially uniform over the entire side. The number of spacers provided thereon is also substantially the same.

Therefore, even when the two substrates 50 and 70 are bonded together while being pressed with a constant force, the sealing material and the spacer are arranged in a well-balanced manner over the entire area, so that the gap can be formed uniformly. it can. In this description,
Since the wiring width is the same, it is provided that the number of wirings is the same on all sides, but in order to further improve the accuracy, the total wiring width Must be considered the same. For example, below a certain sealing material, the total width (20, 20, 10 μm) is 5
0 μm, and if only one 20 μm wiring is provided on another side, the total width becomes the same if one 30 μm is provided as a dummy wiring or two 20 μm and 10 μm are provided as dummy wirings. The balance can be further improved.

On the other hand, the wiring width actually used under the sealing material is mainly about 10 μm to 22 μm, but only the power supply is about 40 μm. The power supply is twice as wide as other wirings, and the corners of the power supply are where distortion is concentrated and cracks are likely to occur. Therefore, in the present application, the slit S
L1 is provided to absorb the distortion, and the slits prevent the wiring from peeling off due to the adhesion between the exposed Si nitride film and the flattening film. Further, in the case where film peeling occurs at a portion other than the corner due to a large width, the film may be provided like a slit SL2.

[0039]

As is clear from the above description, the first
By providing the sealing material on the flattening film corresponding to between the driver circuit and the side of the first transparent substrate, a Si nitride film having good adhesion exists on both sides of the wiring,
The adhesion between the Si nitride film on both sides and the flattening film can prevent the peeling of Al, and can improve the yield and suppress the aging.

Second, by providing dummy wirings so as to be substantially equal to the maximum number of wirings included in the sealing material,
Al peeling and non-uniform gap can be eliminated, and a liquid crystal display device with excellent display and no change over time can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a liquid crystal display device of the present invention.

FIG. 2 is a diagram illustrating a method of applying a sealing material.

FIG. 3 is a diagram illustrating a method of applying a sealing material.

FIG. 4 is a plan view illustrating a corner of the liquid crystal display device.

FIG. 5 is a plan view illustrating a conventional liquid crystal display device.

FIG. 6 is a cross-sectional view of a pixel portion of a liquid crystal display device.

FIG. 7 is a plan view of a conventional liquid crystal display device.

[Explanation of symbols]

 14 First transparent substrate 16 Precharge driver 17 Drain driver 18 Gate driver 19-25 Wiring 73 Sealing material 76 Sealing material DH Dummy wiring SL Slit

Claims (3)

[Claims] A first transparent substrate; a display region formed on the first transparent substrate, the display region including transistors and display electrodes connected thereto connected in a matrix; a display region surrounding the display region; A driver circuit formed between the first transparent substrate and a terminal provided on a side of the first transparent substrate, and extending around the first transparent substrate to electrically connect the driver circuit to the driver circuit. And the first wiring
A second transparent substrate disposed to face the transparent substrate, a counter electrode provided on the second transparent substrate, an alignment film provided on the first transparent substrate and the second transparent substrate, In a liquid crystal display device having a sealing material mixed with a spacer provided between a first transparent substrate and the second transparent substrate, and a liquid crystal sealed through the sealing material, the transistor And unevenness made of a material constituting the driver circuit is filled with a flattening film, and the sealing material is provided on the flattening film corresponding to between the driver circuit and a side of the first transparent substrate. A liquid crystal display device characterized by the following. 2. A sealing material is located outside the driver circuit, on a wiring extending in a longitudinal direction of the driver circuit, and substantially equal to the maximum number of wirings included in the sealing material. 2. The liquid crystal display device according to claim 1, wherein a dummy wiring is provided. 3. A sealing material is located on the outside of the driver circuit, on a wiring extending in a longitudinal direction of the driver circuit, and is substantially equal to the sum of the maximum number of wiring widths included in the sealing material. 2. The liquid crystal display device according to claim 1, wherein a dummy wiring is provided so as to form a dummy wiring.