JPH112828A - Liquid crystal image display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve aperture rate by forming a counter electrode in a grating shape on scanning lines and signal lines across a thick insulating layer. SOLUTION: When a terminal electrode 24 is formed for a scanning line 8, an opening part 22 is formed in the thick transparent insulating layer 21 and after a 1st silicon nitride layer 13 as a gate insulating layer in the opening part 22 is removed, the terminal electrode 24 of the scanning line 8 and terminal electrode 5 of a signal line 7 are formed of a 3rd metal layer, so that the opening part can be formed in the insulating layer only once. Here, the terminal electrode 24 of the scanning line 8 and the terminal electrode 5 of the signal line 7 is not made independent, but connected by a thin pattern 25 and then the scanning line 8 and signal line 7 short-circuit, so an electrostatic measure is taken in a liquid crystal cell forming process. Thus, the counter electrode is formed in the grating shape on the scanning lines 8 and signal lines 7 across the thick transparent insulating layer 21 to evade the concentration of a charging and a discharging current of the liquid crystal cell in the row direction of the counter electrode, which can be made thin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal image display device comprising a thin film semiconductor element as a switch element.
In particular, it is deeply related to the technology related to the expansion of the viewing angle.

[0002]

2. Description of the Related Art An active type liquid crystal image display device in which a thin film transistor using amorphous silicon as a semiconductor material is incorporated in each pixel as a switching element is rapidly expanding in substrate size in combination with efforts to improve productivity. However, at present, the adoption of a glass substrate having a size of 550 × 650 mm or more is being commercialized to a screen size exceeding 20 inches (50 cm).

FIG. 5 is a perspective view of such a liquid crystal panel 1. On one transparent insulating substrate, for example, a glass substrate 2, a thin film transistor as a switching element and a pixel are provided at each intersection of a scanning line and a signal line. The electrodes are arranged in a two-dimensional matrix to form an image display unit. A video signal is supplied to the signal line 7 by, for example, TCP mounting using the film carrier 4 to the terminal electrode 5 formed at the distal end of the signal line 7, and the terminal electrode 24 at the distal end of the scanning line 8 (to be described later). (Not shown here), a scanning signal is supplied to the scanning line 8 by COG mounting for directly connecting the semiconductor chip 3, for example, and an image is displayed on an image display unit. Here, for the sake of convenience, two types of mounting methods are shown at the same time, but in practice any one of the methods is appropriately selected and adopted. Reference numeral 6 denotes another glass substrate facing the image display unit, and a liquid crystal is filled in a space having a thickness of several μm sandwiched between the two glass substrates 2 and 6 to function as an optical element. In many cases, a colored layer made of an organic thin film corresponding to each unit pixel or each signal line is provided on the inner surface of the opposing glass substrate 6 which is in contact with the liquid crystal, and a color image is displayed. It is often called a color filter.

The scanning line 8 and the terminal electrodes 24 at the tip of the scanning line,
The signal line 7 and the terminal electrode 5 at the distal end of the signal line need not necessarily be formed of the same conductive member.
If the steps of forming an opening in the signal line 7 and forming a conductive thin film are added, the degree of freedom of selection is high.

FIG. 6 shows an equivalent circuit of an active type liquid crystal image display device using an insulated gate transistor 9 as a switch element, wherein 7 is a signal line, 8 is a scanning line, and 10 is a liquid crystal cell. The elements drawn by solid lines are formed on one glass substrate 2 constituting the liquid crystal image display device, and the common electrode 11 common to all the liquid crystal cells 10 drawn by dotted lines is no longer used in the conventional liquid crystal image display device. Although formed on one counter glass substrate 6, it is formed on the same glass substrate 2 in an IPS type liquid crystal image display device described later. OFF resistance of insulated gate transistor 9 or liquid crystal cell 1
When the resistance of 0 is low or when the gradation of a display image is emphasized, a circuit such as adding an auxiliary storage capacitor 12 in parallel with the liquid crystal cell 10 to increase the time constant of the liquid crystal cell 10 as a load. Ingenuity is added.

FIG. 7 shows a case where a TN (twisted nematic) type liquid crystal material is used and upper and lower transparent electrodes 41 and 42 are used.
FIG. 7 is a conceptual diagram showing the amount of change in viewing angle when a conventional liquid crystal cell is constituted by two glass plates 43 and 44 on which are formed.
There is a disadvantage that the viewing angle is narrow due to poor symmetry of the liquid crystal molecules 50 in the thickness direction of the liquid crystal cell.

On the other hand, as shown in FIG.
Even if an N-type liquid crystal material is used, if the comb-shaped electrodes 47 and 48 are arranged in parallel on one glass substrate 45, the symmetry of the liquid crystal molecules 50 in the thickness direction of the liquid crystal cell is improved, and the viewing angle is increased. Is greatly expanded. In FIG. 8, since the liquid crystal molecules 50 are rotated on the lower one glass substrate 45 by application of a voltage, such a driving method is called IPS (In Plain).
Switchig). Reference numeral 46 denotes another counter glass substrate or a color filter for forming a liquid crystal cell.

FIG. 9 is a plan view of a unit picture element of an active substrate constituting a liquid crystal image display device according to the IPS system.
Shows a cross-sectional view taken along the line AA 'in FIG. 9, and the manufacturing process thereof will be briefly described below.

First, as shown in FIG. 10A, a glass substrate 2 as an insulating substrate having high heat resistance and high transparency, for example, on one main surface of a product name 1737 manufactured by Corning Incorporated, such as SPT 0.2 μm film thickness using vacuum film forming equipment
For example, as a first metal layer, a Cr thin film is applied,
The gate electrode 8 also serving as a scanning line and the counter electrode 11 are selectively formed by fine processing technology.

Next, as shown in FIG. 10B, a first silicon nitride layer (SiNx) 13 serving as a gate insulating layer is formed on the entire surface of the glass substrate 2 by using a PCVD apparatus, and the insulating gate is substantially free of impurities. Amorphous silicon layer (a-Si) 14 and second
The three types of thin film layers of the silicon nitride layer 15
Then, the second silicon nitride layer 15 on the gate electrode 8 is selectively left to 15 'by a fine processing technique to expose the first amorphous silicon layer 14. .

Next, a second amorphous silicon layer 16 containing, for example, phosphorus as an impurity is deposited to a thickness of, for example, 0.05 μm on the entire surface by using a PCVD apparatus. After selectively forming openings on the scanning lines 8 at the periphery of the glass substrate 2 necessary for electrical connection of the substrate, as shown in FIG. 10C, using a vacuum film forming apparatus such as SPT. As a second metal layer having a thickness of about 0.3 μm, for example, an AL thin film is applied, and a signal line (source wiring) 7 and a picture element (drain) electrode 17 are selectively formed by a fine processing technique. At this time, the second and first amorphous silicon layers 16 and 14 are also removed by using the photosensitive resin pattern and the AL thin film layer used for forming the electrodes and wirings as a mask to remove the first silicon. The nitride layer 13 is exposed. In order that the insulated gate transistor does not have an offset structure, the source / drain wirings (electrodes) 7 and 17 are formed in a positional relationship that partially overlaps the gate electrode 8 in a planar manner. It is also common to form a gate wiring (not shown) simultaneously with the signal line 7 including the opening on the scanning line 8.

Even in this state, the liquid crystal cell can operate as an active substrate. However, a direct current component enters the liquid crystal cell, and the liquid crystal is deteriorated due to high temperature operation or continuous operation for a long period of time. Therefore, as shown in FIG. 10D, a transparent insulating layer, for example, a third silicon nitride layer 18 is further formed on the entire surface of the glass substrate 2 by PCVD.
An active substrate is completed by depositing about 0.3 μm using an apparatus. Of course, the third silicon nitride layer 18 which is a passivation insulating layer on the terminal electrodes of the scanning lines 8 and the signal lines 7 is provided around the glass substrate 2 so that an electric signal can be supplied to the scanning lines 8 and the signal lines 7. The terminal electrode is exposed by being selectively removed.

In the above-described manufacturing process, the configuration of the liquid crystal image display device is described with respect to the minimum constituent factors for easy understanding. Therefore, for example, in order to improve the heat resistance of the insulated gate transistor, Cr, Mo, T are formed between the source / drain wirings 7 and 17 and the second amorphous silicon layer 16 ′ containing impurities and serving as the source / drain.
i, or a technique of interposing a heat-resistant barrier metal such as a silicide thereof, a technique of reducing the resistance value by multiplying the gate metal layer 8, or a technique of preventing an interlayer short circuit between the scanning line 8 and the signal line 7. Omitted the description. In addition, descriptions of spacers and sealing materials constituting a liquid crystal cell, members for an alignment film, a polarizing plate, and the like necessary for operating the liquid crystal cell, and constituent factors required for an optical element such as a back light source are omitted. doing.

The unit pixel of the IPS system in which the pixel (drain) electrode 17 and the counter electrode 11 made of metal shown in FIG. 9 are opposed in a comb shape on the same substrate is the same as the conventional transparent pixel electrode. When compared with a unit pixel in which a transparent counter electrode is opposed to a transparent substrate in a sandwich manner on a separate transparent substrate, the former has an overwhelmingly low aperture ratio of 40% or less, and the latter has an overwhelmingly low 60% or more, and a bright image cannot be obtained. The reasons are 1) the picture element electrode 17 and the counter electrode 11 are composed of a metal thin film, 2)
This is because the picture element electrode 17 and the counter electrode 11 themselves do not contribute to the display, and the transparent area between the picture element electrode 17 and the counter electrode 11 contributes to the display. The electrode 17 and the counter electrode 11 need to be miniaturized as much as possible.

Although miniaturization of the pixel electrode 17 is a problem of the resolution limit of the exposure device and the etching accuracy, the counter electrode 11 is provided with a current for charging and discharging the liquid crystal cell in a row (lateral) direction for each pixel. Since the integration is performed, it has a very important meaning for increasing the number of display pixels and the display screen. In order to prevent an increase in the voltage drop due to the resistance value of the counter electrode, there is a design limitation in making the counter electrode 11 slender in the row (horizontal) direction and in FIG. 9 to reduce the pattern width in the vertical direction. I do.

When the auxiliary capacitor 12 is introduced to increase the time constant of the liquid crystal cell, a current for charging and discharging the auxiliary capacitor 12 is also added, so that the pattern width of the counter electrode 11 must be increased in the vertical direction. There is. In FIG. 9, a region 19 where the picture element (drain) electrode 17 and the counter electrode 11 overlap with each other via the gate insulating layer and the first and second amorphous silicon layers constitutes the auxiliary capacitance 12. .

[0017]

An IPS type liquid crystal image display device having a wide viewing angle but a low aperture ratio and difficult to obtain a bright image is to be put to practical use by eventually obtaining a bright image with a strong back light source. Has priority, and there is a major problem from the viewpoint of power consumption.

The present invention has been made in view of the above situation, and has as its object to provide an IPS type liquid crystal image display device having a high aperture ratio.

[0019]

According to the present invention, there is provided an insulated gate transistor on one main surface, a pixel electrode connected to a drain of the insulated gate transistor, and a predetermined distance from the pixel electrode. A first transparent insulating substrate in which unit picture elements each having at least one counter electrode formed at a distance are arranged in a two-dimensional matrix, and a second transparent insulating substrate or a color filter; In a liquid crystal image display device filled with liquid crystal, a grid-like counter electrode is formed on a scanning line and a signal line via a thick transparent insulating layer formed on the first transparent insulating substrate. It is a feature.

As described above, the counter electrode is formed in a cross shape in order to avoid concentration of the charging / discharging current in the row (horizontal) direction. As a result, the charging / discharging current flows dispersedly in the vertical and horizontal directions. Can be narrowed. In addition, since it is formed on the scanning line or the signal line via the thick insulating layer, the area which contributes to the display is increased in addition to the reduction of the effective resistance value of the counter electrode, and the aperture ratio is further increased.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an insulated gate transistor on one main surface, a picture element electrode connected to a drain of the insulated gate transistor, and the picture element electrode. And a first transparent insulating substrate in which unit picture elements having at least one counter electrode formed at a predetermined distance are arranged in a two-dimensional matrix,
In a liquid crystal image display device in which a liquid crystal is filled between a second transparent insulating substrate and a color filter,
A grid-like counter electrode is formed on the scanning line and the signal line via a thick transparent insulating layer formed on a transparent insulating substrate of The terminal electrodes of the scanning lines and the signal lines including the openings formed in the thick transparent insulating layer are formed in the same step as the counter electrodes.

According to a second aspect of the present invention, there is provided a method for forming a scanning line serving also as a gate of an insulated gate type transistor comprising at least one first metal layer on a transparent insulating substrate; A step of forming a gate insulating layer, a semiconductor layer serving as a channel, and a semiconductor layer containing impurities serving as sources and drains; and forming a signal (source) line and a drain electrode formed of one or more second metal layers. Forming a thick transparent insulating layer on the entire surface, forming an opening in the thick transparent insulating layer on the position where the scanning and signal line terminal electrodes are formed, and forming an insulating layer in the opening on the scanning line. Removing and selectively exposing the scanning lines, grid-like counter electrodes on the scanning lines and the signal lines on the thick insulating layer, and terminal electrodes of the scanning lines and the signal lines including the openings. To one or more third metal layers Is characterized in that a step of forming.

By arranging the scanning electrodes on the signal lines and the signal lines in a grid pattern through the thick transparent insulating layer as described above, concentration of the charge / discharge current of the liquid crystal cell in the row direction of the counter electrodes can be avoided. In addition, the counter electrode can be made thinner, and the aperture ratio can be improved. Further, the area between the picture element electrode and the counter electrode which contributes to the display is enlarged, and the aperture ratio can be further improved. Further, since the formation of the opening in the transparent insulating layer can be rationalized, it is possible to compensate for the disadvantage that the manufacturing process is longer than in the conventional manufacturing method.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. For the sake of convenience, the same reference numerals are given to the same or corresponding parts as in the conventional example. (Embodiment) FIG. 1 is a plan view of a unit picture element of an active substrate according to an embodiment of the present invention, and FIGS. 2 and 3 are manufacturing process diagrams thereof, which are shown in FIGS. (A),
FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. 1, and FIG. 3C is a cross-sectional view taken along line CC ′ of FIG. Although the semiconductor device for a liquid crystal image display device according to the present invention is manufactured through substantially the same manufacturing process as the conventional one, a part of the manufacturing process is rationalized so that the number of manufacturing processes is not increased. The details of the manufacturing process will be described with reference to the cross-sectional view taken along the line BB 'of FIG.

First, as shown in FIG. 2A, a first metal layer having a thickness of about 0.2 μm, for example, C, is formed on one main surface of the glass substrate 2 by using a vacuum film forming apparatus such as SPT.
A gate electrode 8 and a storage electrode 20 which also serve as scanning lines are selectively formed by depositing an r thin film and using a fine processing technique.

Next, as shown in FIG. 2B, a first silicon nitride layer (SiNx) 13 serving as a gate insulating layer is formed on the entire surface of the glass substrate 2 by using a PCVD apparatus, The three types of thin film layers, i.e., a first amorphous silicon layer (a-Si) 14 and a second silicon nitride layer 15 which are to be channels of a type transistor, are formed to a thickness of, for example, 0.5.
The first amorphous silicon layer 14 is exposed by 3-0.05-0.1 μm, and the second amorphous silicon nitride layer on the gate electrode 8 is selectively left at 15 ′ by a fine processing technique.

Next, as shown in FIG.
Using a CVD apparatus, a second amorphous silicon layer 16 containing, for example, phosphorus as an impurity is deposited on the entire surface with a thickness of, for example, 0.05 μm. Up to this point, the manufacturing process is exactly the same as the conventional example.

In the next step, unlike the conventional example, a signal line and a drain electrode are formed. Figure 3
As shown in (a), a second metal layer having a film thickness of about 0.3 μm is formed using a vacuum film forming apparatus such as SPT.
An L thin film is deposited, and a signal line (source wiring) 7 and a drain electrode 17 are selectively formed by a fine processing technique. At this time, the second and first amorphous silicon layers 16 and 14 are also removed by using the photosensitive resin pattern used for forming the AL thin film and the electrodes as a mask to remove the first silicon nitride layer 13. Expose.

The reason why the number of the second metal layers is one or more is that a barrier metal layer is interposed for improving the heat resistance of the thin film transistor. The + Al layer may have a two-layer structure. In two cases, as shown in FIG. 4B, the surface of the signal line 7 exposed in the opening 23 is made of an appropriate metal so that the surface of the signal line 7 is not removed or deteriorated by an unnecessary reaction when the gate insulating layer 13 is removed. As a result, the signal line 7 can have a three-layer structure of a barrier metal layer + an Al layer + a suitable metal layer.

Then, as shown in FIGS. 3B, 4A and 4B, a highly transparent insulating layer 21 having a thickness of, for example, about 2 to 3 μm is applied to the entire surface, and The opening 2 is formed at a position where the terminal electrodes of the scanning line 8 and the signal line 7 are formed in the region.
2 and 23 are formed to partially expose the signal line 7. At this time, it is needless to say that the photo-etching process can be rationalized by using a photosensitive (for example, product name: Optmer: PC302 made by Japan Synthetic Rubber) for the transparent insulating layer 21. Further, after selectively removing the gate insulating layer 13 in the opening 22 to partially expose the scanning line 8, an AL thin film having a thickness of, for example, about 0.3 μm is deposited as a third metal layer, The terminal electrodes 24 of the scanning lines 8 and the terminal electrodes 5 of the signal lines 7, including the openings 22 and 23,
A grid-like counter electrode 11 'is formed on the upper side and the semiconductor device for an image display device according to the embodiment of the present invention is completed.

FIG. 4 shows a plan view of a terminal electrode formed outside the image display section and a cross-sectional view thereof along the line DD ′ and EE ′. FIG. 4 (b) corresponds to the terminal electrode 5 on the signal line 7 side.

The reason why the insulating layer 21 is so thickly applied is that the capacitance formed by the counter electrode 11 ′ with the scanning line 8 and the signal line 7 via the insulating layer 21 is to be minimized. This is because these capacitances all increase the load capacitance of the scanning lines 8 and the signal lines 7 and eventually increase the power consumption of the driving circuit. By the way, using a general silicon nitride layer to form such a thick insulating layer is not practical in terms of the time required for film formation, internal stress generated inside the film, etc. As described above, a coating / curing type resin seems to be optimal.

It goes without saying that, when the counter electrode 11 'is formed on the insulated gate transistor 9 by extending the counter electrode 11', a light shielding function is provided. The opposite electrode 11 'is made of a metal having a low reflectance.
For example, it is also clear that when formed or laminated with Cr, Ti, Mo, or the like, the reflected light from these electrodes is reduced and the contrast ratio of the displayed image is improved. It is also possible to form a matrices function on the active substrate 2.

In the conventional manufacturing method, an opening is formed in the first silicon nitride layer 13 as a gate insulating layer to form a terminal electrode of a scanning line, and the third silicon nitride layer 18 as a passivation insulating layer is formed. An opening is formed in the substrate to expose terminal electrodes of the scanning line and the signal line. That is, two opening forming steps are required. However, in the manufacturing method according to the embodiment of the present invention, in order to avoid an increase in the number of manufacturing steps, when forming the terminal electrode 24 on the scanning line 8, the thick transparent insulating layer 21 After the first silicon nitride layer 13 as the gate insulating layer in the opening 22 is removed, the terminal electrode 24 of the scanning line 8 and the signal line 7 are formed with the third metal layer. By forming the terminal electrode 5 described above, it is possible to form the opening in the insulating layer only once.

Although the details are omitted in FIG. 4, if the terminal electrode 24 of the scanning line 8 and the terminal electrode 5 of the signal line 7 are connected by a thin pattern 25 without being independent, the scanning line 8 and the signal line 7 is short-circuited, so it goes without saying that it is a countermeasure against static electricity in the liquid crystal cell forming process.

[0036]

As described above, the IP according to the present invention is
In an S-type liquid crystal image display device, in order to avoid concentration of charging / discharging current of a liquid crystal cell in a row direction of a counter electrode, the counter electrode is formed in a grid pattern on a scanning line and a signal line via a thick insulating layer. doing. For this reason, the charge / discharge current of the liquid crystal cell is dispersed in the peripheral direction, which has an effect equivalent to a significant decrease in the resistance value of the counter electrode, and the pattern width of the counter electrode connecting the counter electrode between unit picture elements is reduced. The aperture ratio can be improved.

Further, by arranging the counter electrode on the scanning line and the signal line via the thick insulating layer, a region contributing to display between the picture element electrode and the counter electrode is enlarged, and the aperture ratio is also improved. .

In addition, when flatness is added to the thick insulating layer, the counter electrode is present on the thick and flat insulating layer, so that the alignment treatment of the alignment film is easily uniformized and the effect of improving the contrast ratio is expected. it can.

The disadvantage that the production process is longer than that of the conventional production method due to the addition of the counter electrode made of metal has been compensated for by rationalizing the formation of the opening in the insulating layer, and is of industrial value. It can be said that there is a certain invention.

As is clear from the above description, the device structure and the manufacturing method related to the introduction of the thick insulating layer are the main points of the present invention. It will be apparent that the present invention is not limited to the material and configuration or the lamination of the signal lines, nor to the existence or configuration of the storage capacitor.

[Brief description of the drawings]

FIG. 1 is a plan view of a unit pixel of an active substrate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process according to the embodiment of the present invention, which is a cross-sectional view taken along line BB ′ of FIG. 1;

FIG. 3 is a cross-sectional view of the manufacturing process following FIG. 2;
And a cross-sectional view along the line CC ′

FIG. 4 is a plan view and a sectional view of a terminal electrode portion of an active substrate according to an embodiment of the present invention.

FIG. 5 is a perspective view of a liquid crystal panel.

FIG. 6 is an equivalent circuit diagram of an active liquid crystal image display device.

FIG. 7 is a conceptual diagram illustrating the viewing angle dependence of a conventional TN liquid crystal cell.

FIG. 8 is a basic principle diagram for explaining the viewing angle dependence of an IPS type TN liquid crystal cell.

FIG. 9 is a plan view of a unit pixel of an active substrate according to a conventional IPS method.

FIG. 10 is a sectional view taken along the line A-A ′ of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 (Active) glass substrate 3 Semiconductor chip 4 Film carrier 5 Terminal electrode of signal line 6 Opposite glass substrate (color filter) 7 Signal line (source wiring) 8 Scanning line (gate electrode) 9 Insulated gate transistor 10 Liquid crystal Cell 11, 11 'Counter electrode 12 Liquid crystal cell 13 First silicon nitride layer (gate insulating layer) 14 First amorphous silicon layer 15 Second silicon nitride layer (etching stopper) 16 (including impurities) 2 amorphous silicon layer 17, 17 'drain (picture element) electrode 18 third silicon nitride layer (passivation insulating layer) 20 storage electrode 21 thick transparent insulating layer 22 opening for connection to scanning line 23 signal Opening for connection to line 24 Terminal electrode of scanning line 25 Short-circuit line for countermeasures against static electricity

Claims (2)

[Claims] 1. An insulated gate transistor on one main surface, a pixel electrode connected to a drain of the insulated gate transistor, and a counter electrode formed at a predetermined distance from the pixel electrode. A liquid crystal image formed by filling a liquid crystal between a first transparent insulating substrate in which unit picture elements each having at least one of them is arranged in a two-dimensional matrix and a second transparent insulating substrate or a color filter In the display device, a grid-like counter electrode is formed on the scanning line and the signal line via a thick transparent insulating layer formed on the first transparent insulating substrate, and the scanning line and the signal line are separated. A liquid crystal image display device, wherein terminal electrodes for a scanning line and a signal line are formed in the same step as the counter electrode, including an opening formed in the thick transparent insulating layer on a terminal electrode forming position. 2. A step of forming a scanning line also serving as a gate of an insulated gate transistor including at least one first metal layer on a transparent insulating substrate, and forming at least a gate insulating layer and a semiconductor layer serving as a channel. A step of forming a semiconductor layer containing impurities serving as a source and a drain, a step of forming a signal (source) line and a drain electrode made of one or more second metal layers, and a step of forming a thick transparent insulating layer over the entire surface. Forming, forming an opening in the thick transparent insulating layer on the position where the scanning and signal line terminal electrodes are formed, and selectively removing the insulating layer in the opening on the scanning line to select the scanning line. An exposing step, a grid-like counter electrode on the scanning line and the signal line on the thick insulating layer, and one or more third metal layers including a scanning line and a terminal electrode of the signal line including the opening. For image display including the step of forming with A method for manufacturing a semiconductor device.