JPH04194823A - Liquid crystal display device and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce production of a point defect by forming a first insulating film with a given thickness on an image signal line having a given thickness and forming a clear picture element electrode, being not present on an area occupied by an image signal line on the first insulating film deposited on the image signal line, on the first insulating film. CONSTITUTION:A liquid crystal orientation film ORI 1, a film transistor TFT, and a clear picture element electrode ITO 1 are formed on the lower clear glass substrate SUB 1 side on a basis of a liquid crystal layer LC. Below the substrate SUB 1, an orientation film ORI 2, a color filter FIL, and a black matrix pattern BM for light shield are formed on the polarizing sheet POL 1 and the upper substrate SUB 2 side, and a sheet POL 2 is formed on the substrate SUB 2. In sectional structure, a layer comprising a common electrode ITO 2, protection films PSV 1 and PSV 2, and an insulating film GI is formed. An image signal line DL formed of first and second conduction films d1 and d2 is formed on the insulating film GI. The protection film PSV 1 is formed thereon, and the electrode ITO 1 is formed after formation of the structure. Thus, two differences in a stage of an image signal line are produced between the adjoining electrodes ITO 1 and no point defect is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device, and particularly to an actite matrix type liquid crystal display device in which pixels are constructed of thin film transistors and pixel electrodes, and a method for manufacturing the same.

[Conventional technology]

Regarding active matrix liquid crystal display devices equipped with TPT (thin film transistors), for example, 19
1989, Institute of Electronics and Communication Engineers Technical Research Report (ED89-32)
41 and Japanese Unexamined Patent Publication No. 62-47621.

[Problem to be solved by the invention]

TPT liquid crystal display devices are used as small, low power consumption display devices, mainly as monitors in microcomputer systems. For such applications, active matrix liquid crystal display devices have a complicated manufacturing process, so they are prone to short-circuit defects, and since these defects can be easily recognized as images, it is possible to reduce these defects. technology is required.

The most common cause of point defects is that the pixel electrode that performs display, which is made of transparent indium tin oxide IT○, is left unprocessed due to resist residue in the photo process or etching failure in the etching process, and the pixel electrode ITO is formed with transparent indium tin oxide IT○. This is a defect that causes an electrical short circuit between the video signal line (drain line) that supplies the video signal from the external drive circuit or between adjacent pixel electrodes IT○.

FIG. 2 shows a cross-sectional structure of a TPT liquid crystal display using the former conventional technique. The same figure (a) is a cross-sectional view taken on a line perpendicular to the video signal line (drain line) DL with respect to the pixel electrode adjacent to the video signal line on the plane, and the same figure (b) is the scanning signal, @GL Pixel electrodes IT adjacent to each other on a plane
3 is a cross-sectional view taken along a line perpendicular to the scanning signal line GL (gate line) with respect to O. FIG.

When using this technology, the pixel electrode IT○ and the video signal line D
Regarding the short circuit of L, it is isolated by 0 insulating films, and measures against defects have been taken in this respect.

However, with respect to the video signal line DL in the same figure, the length L
ITO between adjacent pixel electrodes formed with a gap of o
As for the short circuit between IT○ and the short circuit between adjacent pixel electrodes IT○ formed with a gap of length Lc from the scanning signal line GL, since they are formed on the same plane, many defects still occur. Of course, as Lo and Lc are increased, this defective rate follows Poisson distribution statistics, and Ln,
Although it decreases exponentially with respect to Lc, this significantly lowers the aperture ratio through which light passes, which is not preferable.

Furthermore, the technique disclosed in Japanese Patent Application Laid-Open No. 62-47621 involves interposing an insulating film at the overlapping region of the pixel electrode on the semiconductor film, and interposing a phosphorus-doped amorphous silicon layer between the source/drain electrode and the semiconductor layer. It is. This conventional example has the same drawbacks as the above-mentioned prior art due to the pixel electrode being provided below the video signal line and the overlapping structure.

An object of the present invention is to provide a technique in a liquid crystal display device that can reduce point defects in which pixels of the liquid crystal display device become defective.

[Means to solve the problem]

The invention disclosed in this application is achieved by the following two means.7 The first method is to first form a video signal line with a predetermined thickness, and then cover the video signal line with an insulating film. , then deposit and process the TO. Alternatively, a scanning video signal line having a predetermined thickness is first formed, then an anodic oxide film is formed by anodizing the electrode material on the scanning signal line, and then IT◯ is deposited and processed. The second one is.

Adjacent pixel electrodes IT○ formed along the video signal line are not formed on the same plane, and the distance between the pixel electrodes ITO on the same plane in the vertical direction of the video signal line is the distance between adjacent video signal lines. Make it bigger.

That is, in the present invention, a thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with the gate electrode of the thin film transistor, and the video signal line is contacted with the drain electrode of the thin film transistor. ,
A unit pixel having a function of driving a liquid crystal by a pixel electrode in contact with the source electrode of the thin film transistor is transparent.
In a liquid crystal display device formed in a matrix shape on an open substrate, a first insulating film having a predetermined thickness is formed on a video signal line having a predetermined thickness, and a transparent pixel electrode is deposited on the video signal line. The first insulating film does not exist on the area occupied by the video signal line on the first insulating film, but is formed on the first insulating film. Here, the video signal line is 3000
It is best to have a thickness of 8 or more.

Further, in the present invention, a thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with a gate electrode of the thin film transistor, and the video signal line is contacted with a drain electrode of the thin film transistor. , in a method for manufacturing a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode of the thin film transistor are formed in a matrix shape on a transparent substrate, a video signal line, a first insulator; The film and transparent pixel electrode are formed in the following order: a video signal line, a first insulating film, and a transparent pixel electrode.

Further, in the present invention, a thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with a gate electrode of the thin film transistor, and the video signal line is contacted with a drain electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode of the thin film transistor are formed in a matrix shape on a transparent substrate, a predetermined thickness is provided on a video signal line having a predetermined thickness. A first insulating film is formed, and a transparent pixel electrode does not exist on the area occupied by the video signal line on the first insulating film deposited on the video line; It is formed in a region where the insulating film is etched away. Here, the transparent pixel electrode does not exist on the area occupied by the video signal line on the first insulating film deposited on the video line, and is etched away on the first 18 films. It is better to have it formed only in the area. Further, it is preferable that the first insulating film whose part is removed has a thickness of 3000 Å or more. Further, it is preferable that both the video signal line and the first insulating film from which a part of the video signal line is removed have a thickness of 3000 Å or more. A thin film transistor is formed in the thin film transistor, the scanning signal line is contacted to the gate electrode of the thin film transistor, the video signal line is contacted to the drain electrode of the thin film transistor, and the liquid crystal is driven by the pixel electrode contacted to the source electrode of the thin film transistor. In a liquid crystal display device having unit pixels formed in a matrix shape on a transparent substrate, the scanning signal lines excluding the first and last of the plurality of scanning signal lines are arranged in a vertical cross-sectional structure on a plane. , a pixel electrode adjacent to the scanning signal line other than the first and last one does not exist on at least one step of an anodic oxide film formed by anodizing the scanning electrode material, and the pixel electrode It is characterized in that the gate insulating film of the thin film transistor does not exist in the opening region on the electrode through which light passes.

Further, in the present invention, a thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with a gate electrode of the thin film transistor, and the video signal line is contacted with a drain electrode of the thin film transistor. , in a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode of the thin film transistor are formed in a matrix shape on a transparent substrate, the first and last of the plurality of scanning signal lines A transparent pixel electrode adjacent to the scanning signal line except the first and the last scanning signal line is formed by anodizing the scanning electrode material in a vertical cross-sectional structure on a plane. The present invention is characterized in that the gate insulating film of the thin film transistor does not exist on the anodic oxide film formed by the method, and the gate insulating film of the thin film transistor does not exist in the opening region on the pixel electrode through which light passes.

Further, in the present invention, the scanning signal line, the anodic oxide film, and the pixel electrode are formed in the order in which the scanning signal line, the anodic oxide film, and the pixel electrode are formed, and during the manufacturing process of the pixel electrode on the anodic oxide film,
This is a manufacturing method of a liquid crystal display device characterized in that the manufacturing method does not include any other insulating film manufacturing process.

In the display device, both the upper and lower electrodes forming the storage capacitor are preferably made of an opaque electrode material. Further, the upper electrode forming the storage capacitor is preferably formed of a pixel electrode, and the total thickness of the scanning signal line and the anodic oxide film is preferably 3000 Å or more.

Further, in the present invention, a thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with a gate electrode of the thin film transistor, and the video signal line is contacted with a drain electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having a function of driving liquid crystal by a pixel electrode in contact with a source electrode of the thin film transistor are formed in a matrix shape on a transparent substrate, the first and last of the plurality of video signal lines The pixel electrodes adjacent to the video signal lines other than the first and last video signal lines, except for the first and last video signal lines, are arranged on a transparent substrate or A video signal line is formed on the first insulating film and is formed on the first insulating film at a position approximately midway between the other pixel electrode and the other pixel electrode, and the other pixel electrode is connected to the video signal line. It is formed on a second insulating film formed on a line. Here, it is preferable that the pixel electrode does not exist on the video signal line. In addition, the scanning signal lines excluding the first and last of the plurality of scanning signal lines are shown in a cross-sectional structure in a vertical direction on a plane, with respect to the scanning signal lines excluding the first and last. One of the adjacent pixel electrodes is formed on a transparent substrate or a first insulating film, and a scanning signal line formed at a substantially intermediate position on a plane with the other pixel electrode is connected to the first insulating film. Preferably, the other pixel electrode is formed on a second insulating film formed on the scanning signal line.

[Effect]

The above-mentioned means 1 is based on the results of the inventor's experiments on step coverage of ITO for steps.

Figure 3 shows the experimental results. The vertical axis is the cutting rate of ITO at the step, and the horizontal axis is the step to be covered by the ITO. When the step is less than 1000 Å, the cutting weight is small, almost 0%, but it is 300 Å.
The cutting rate increases sharply at 0 Å or more, and reaches 90% or more at 4,000 Å or more.7Based on this experimental result, first, as in method 1 above, an image of a predetermined thickness (preferably 3,000 or more) is cut. Forming a signal line or a scanning signal line, covering it with an insulating film or anodizing the electrode material of the scanning signal line,
If 1TO is then deposited and processed, even if ITO remains between adjacent pixel electrodes due to poor etching or the like, rT◯ is cut off at the step, reducing short-circuit defects.

The means 2 is a pixel electrode IT' in the vertical direction of the video signal line.
Since the distance between 0 and 0 is greater than the distance between adjacent video signal lines, short-circuit failures are significantly reduced according to Poisson distribution statistics for distance.

〔Example〕

(Example 1) One pixel of the liquid crystal display section of the active matrix type liquid crystal display device which is Example 1 of the present invention is shown in FIG. 4 (principal part plan view). The cut cross section is shown in Figure 1. FIG. 5 shows a cross section taken along the line ``--'' in FIG. 4. Further, FIG. 6 shows a cross section taken along the line ``--'' in FIG. 4.

As shown in FIG. 4, the liquid crystal display device includes a thin film transistor T on the inner surface (liquid crystal side) of the lower transparent glass substrate.
A pixel having a PT and a pixel electrode IT○ is configured.

Each pixel consists of two adjacent scanning signal lines (gate signal lines)
It is arranged in the intersection area of GL and two adjacent video signal vA (drain signal lines) DL (in the area surrounded by four signal lines). Each pixel is a thin film transistor TPT
, a pixel electrode ITO, and an additional capacitor Cadd. The scanning signal lines OL extend in one column direction, and a plurality of scanning signal lines OL are arranged in the row direction.

The video signal lines DL extend in the five row direction, and a plurality of video signal lines DL are arranged in the column direction.

As shown in FIG. 1, the cross-sectional structure has a liquid crystal alignment film 0R11 on the lower transparent glass substrate 5UBI side with the liquid crystal layer LC as a reference.
, a thin film transistor TPT and a transparent pixel electrode ITOI are formed, and a polarizing plate POL 1 is formed under the lower substrate 5UB1.
, an alignment film 0RI2 is provided on the upper transparent glass substrate 5UB2 side.
, a color filter FIL, and a light-shielding blank matrix pattern BM are formed on the transparent glass substrate ST, 'B2.
A polarizing plate POL2 is formed on top. In addition, the above cross-sectional structure includes a common transparent pixel type 1ITO2, protection @PSVI
, PSV2, and an insulating film GI are formed.

The feature of this embodiment lies in the cross-sectional structure shown in FIG. Insulating film GI
There is a video signal line DL formed by a stacked structure of a first conductive film d1 and a second conductive film d2 on top, and a protective film PSVI film is formed on it, and the protective film PSVI is processed by photo-etching technology. has been done. The pixel electrode IT○1 is formed after the structure is formed. Therefore, the adjacent pixel electrode Ir
There are two steps between the video signal lines between O2. Even if the pixel electrode ITO1 remains on a residual film in the gap of length L between adjacent ones that induces a point defect, the line is disconnected due to the step difference at the two locations according to the experimental data shown in FIG. 3, and no point defect occurs. The detailed formation conditions of the main components in this sectional view are shown below.

'M! The m film GI is used on the gate insulating film of the thin film transistor TPT. The six insulating films are, for example, silicon nitride films formed by plasma GVD, and have a thickness of 3000 (
It is formed with a membrane thickness of about the same level as that of humans.

The video signal line DL is configured by sequentially overlapping a first conductive film d1 and a second conductive film d2. The first conductive film d1 is a chromium film formed by sputtering, and has a film thickness of 500 to 100%.
It is formed with a film thickness of 0 (person) (in this example, a film thickness of about 600 (person)).

The chromium film has good contact with the N+ type semiconductor layer dO of the thin film transistor TPT, which will be described later, and with the pixel electrode IT○1. Further, the chromium film is a second conductive film d, which will be described later.
It forms a so-called barrier layer that prevents the aluminum of No. 2 from diffusing into the N+ type semiconductor layer do. The first conductive film may include a high melting point metal (Mo) in addition to the above-mentioned ROM film.

It may be formed using a Ti, Ta, W) film or a high melting point metal silicide film. The second conductive film d2 is formed by aluminum sputtering to a film thickness of 3500 to 4500 CA) (in this embodiment, a film thickness of about 4000 CA). The aluminum layer has less stress than the chromium layer.
It is possible to form a thick film and is configured to reduce the resistance value of the video signal line DL. In addition to the aluminum film, it may be formed of an aluminum film containing silicon (Si), baladium (Pd), or copper (Cu) as an additive.

Pixel electrode IT○1 is formed by sputtering with a thickness of 1000 to 20
The film thickness is approximately 1,200 (persons) in this embodiment.

The protective film PSVI is mainly formed to protect the thin film transistor TPT from moisture, and a material with good moisture resistance is used. For example, a silicon oxide film formed by plasma CVD, a silicon nitride film, or an organic film such as PIQ! It is formed by the membrane.

Next, the cross-sectional structure shown in FIG. 5 will be explained. This cross-sectional view shows the liquid crystal L.
A 5-pixel electrode ITO1, which is a cross-sectional view including a thin film transistor TPT for charging the capacitance of C, is formed after photoetching the protective film PSVI, and is in contact with the first conductive film d1 of the source electrode SDI. The second conductive film d2 of the source electrode SDI is covered with a protective film PSVI.

When a positive bias is applied to the gate voltage iGT of the thin film transistor TPT, the source/drain (video signal line DL)
The channel resistance value between the two is small, and when the bias is set to zero, the channel resistance value becomes large. This thin film transistor TPT mainly includes a gate electrode GT,
Gate insulating film Gl, type 1 (intrinsic, 1ntrinsic,
It is composed of an amorphous Si semiconductor layer AS (not doped with conductivity type determining impurities), a pair of source electrodes SDI, and a drain electrode 5D2 (video signal line DL). Note that the source and drain are originally determined by the bias polarity between them.
In the circuit of this display device, the polarity is reversed during operation, so
It should be understood that the source and drain are interchanged during operation.

For convenience, one is expressed as a source and the other as a drain.

Next, three cross-sectional views for explaining the cross-sectional structure in FIG. 6 show the structure of the additional capacitor Cadd. The transparent pixel electrode IT○1 is formed so as to overlap the adjacent scanning signal line GL at the end opposite to the end connected to the thin film transistor TPT. In this superposition, the adjacent scanning signal line GL is used as one electrode PLI, and is brought into contact with the transparent pixel electrode ITOI,
a first conductive film d1 formed in the same process as the video signal line;
A storage capacitor element (electrostatic capacitor element) Ca d d is configured in which the second conductive film d2 is the other electrode PL2. The dielectric film of this storage capacitor element Cadd is a thin film transistor TPT.
It is composed of the same layer as the insulation @G used on the gate insulation film.

The scanning signal line GL, that is, the gate electrode GT in the above invention is made of, for example, chromium (Cr), aluminum (Afl),
It is made of metal such as tantalum (Ta). In addition, in order to increase the electrical breakdown voltage of the insulating film GI, and to increase the electrical breakdown voltage of the insulating film GI,
In order to reduce short-circuit defects between the storage capacitor element Cadd and the scanning signal line GL, and the storage capacitor element Cadd, the metal may be anodized to form an alumina insulating film and a tantalum pentoxide insulating film. When these anodic oxide films are used, the insulating layer of the thin film transistor TPT and storage capacitor element Cadcl is formed on the insulating film GI and the composite film on the anodic oxide film.

Although the above embodiments have shown examples in which one thin film transistor is formed in each pixel, the present invention can be applied even if a plurality of thin film transistors are formed in each pixel.

Finally, FIG. 7 shows an equivalent circuit of the display matrix section and its connection diagram when the pixel structure of this embodiment is used.

Although this figure is a circuit diagram, it is drawn to correspond to the actual geometrical arrangement. AR is a two-dimensional matrix array of multiple pixels.

In the figure, X means a video signal line DL, and subscripts G, B, and R are added corresponding to green, blue, and red pixels, respectively.

Y means scanning signal line GL, and subscripts 1, 2, 3, etc.
...end is added according to the order of scan timing.

Video signal lines X (subscript omitted) are alternately placed on the upper side (or odd
It is connected to the video signal drive circuit He and the lower (or even number) video signal drive circuit Ho.

SUP is a power supply circuit that obtains multiple divided and stabilized voltage sources from one voltage source, and information for the CRT (cathode ray tube) from the host (upper processing time) and information for the TPT liquid crystal display panel. This is a circuit that includes a circuit that converts

(Embodiment 2) FIG. 8 shows a cross section cut along a vertical line in the plane structure of a video signal line of one pixel of a liquid crystal display section of an active matrix type liquid crystal display device according to a second embodiment of the present invention.

The feature of this embodiment lies in the cross-sectional structure shown in FIG. Insulating film GI
There is a video signal line DL formed of a laminated structure of a first conductive film d1 and a second conductive film d2 on top, and a protective film P is on top of the video signal line DL.
An SVI film is formed, and the protective film PSVI is processed using a photo-etching technique. The pixel type 1'MIT○1 is formed after the structure is formed. Therefore, the adjacent pixel electrode I
Between rO2, there are two processing steps of the protective film PSVI with a step difference of 4000 Å or more, and two steps of the video signal line. Alley T○1 with pixels in the gap between adjacent lengths that induces 7-point defects.
Even if it remains on the residual film, it will be disconnected due to the steps at the four locations, according to the experimental data in FIG. 3, and no point defects will occur. In the cross-sectional structure of FIG. 1 and this description, the height difference (due to the protective film PSVL and the video signal!DL) between two adjacent pixel electrodes T○1 with the video signal line DL in between is 3000.
However, in this embodiment, the effects of the present invention can be achieved even if the number of video signal lines is 3000 (people) or less.

(Third Embodiment) FIG. 9 shows a cross section cut along a vertical line in the planar structure of a scanning signal line for one pixel of a liquid crystal display section of an active matrix type liquid crystal display device according to a third embodiment of the present invention.

The feature of this embodiment lies in the cross-sectional structure shown in FIG. On the scanning signal line GL, the scanning signal line, that is, the electrode GT to the gate 1 is an electrode material. For example, aluminum (AQ), tantalum (T
It is made of metal such as a).

The metal is an anodic oxide film A○, that is, an alumina insulating film, 5
Form a tantalum oxide insulating film. The pixel electrode ITOI is formed after forming the structure. After that, an insulating film GI is formed. On the insulating film GI, there is a video signal line DL formed with a laminated structure of a first conductive film d1 and a second conductive film d2. Therefore, with respect to the scanning signal line GL, the adjacent pixel electrode IrO
There is a difference between the scanning signal mGL and its dismounting oxide film A○ between 2, and when the step is 3000 Å or more, the step causes a disconnection according to the experimental data in Figure 3, and the electrical connection between adjacent pixel electrodes with respect to the scanning signal IGL No point defects occur due to short circuits. In this case, the upper electrode of the storage capacitor Cadd is connected to the video signal line DL.
The first conductive film d1 and the second conductive film d2 are formed in a process similar to the above.

Another feature of this embodiment is that the insulating film GI is not present on the pixel electrode IrO1 through which light passes (the region indicated by LT in FIG. 9). Of course, the first conductive film is in contact with the pixel electrode ITO in regions r and c. Pixel electrode I
The insulation on rO1 affects afterimage, which is a defect in display quality. If the pixel electrode ITo1 has an insulating film GI and a protective film PSVI formed in different processes, GI and PSVI
Charge is accumulated on the interface of the image and the afterimage becomes larger. In the present invention, since there is no insulation 11@GI on the pixel electrode tiIT○1, afterimage defects can be reduced. Further, since the #lAl film GT once deposited on the pixel electrode ITOY is used on the gate insulating film of the thin film transistor TPT, its formation temperature is higher than that of the protective film PSVI in order to stabilize the thin film transistor. Therefore, the surface of the pixel electrode ITOI on the surface through which light is transmitted is reduced due to the hydrogen contained in the insulating film GI, and the transmittance decreases. Therefore, removing the surface of the pixel electrode ITOI that has been reduced in the removal process by removing the #4A edge film GI in the light-transmitting region on the pixel electrode ITOI is effective in creating a liquid crystal display device with high transmittance. realizable.

(Embodiment 4) FIG. 10 shows a cross section cut along a vertical line in the planar structure of the scanning signal line of one pixel of the liquid crystal display section of an active matrix type liquid crystal display device according to Embodiment 4 of the present invention.

The feature of this embodiment lies in the cross-sectional structure shown in FIG.

In this case, the upper electrode of the storage capacitor Cadd is the pixel electrode IT.
Formed by O. Therefore, the insulating film of the storage capacitor Cadd is an anodic oxide film A
Since the holding capacitor Cadd can be formed using only a small plane area, the aperture ratio can be increased compared to the fourth embodiment.

It has the characteristic of providing a bright screen display.

Another feature of this embodiment, similar to the third embodiment, is that the insulating film GI is not present on the pixel electrode ITOI through which light passes (the region indicated by Lt in FIG. 9). Of course, the first conductive film is in contact with the pixel electrode IT○1 in the LC region. The insulation on the pixel electrode IrO2 affects afterimage, which is a defect in display quality. If the pixel electrode ITOI has an insulating film GI and a protective film PSVI formed in separate processes,
Charges are accumulated at the interface between GI and PSVI, increasing the afterimage. In the present invention, since there is no insulating film GI on the pixel electrode ITOI, afterimage defects can be reduced. Furthermore, the insulation IIGT once deposited on the pixel electrode ITOI is a thin film transistor TPT.
Since it is used over the gate insulating film of the protective film PSVI, its formation temperature is higher than that of the protective film PSVI in order to stabilize the thin film transistor.

Therefore, the surface of the pixel electrode IT○1 on the surface through which light is transmitted is reduced due to the hydrogen contained in the insulating film GI, and the transmittance decreases. Therefore, by removing the insulating film GI in the light-transmitting region on the one-pixel type IIT○1, the surface of the pixel electrode ITOI reduced in the removal process can be removed, making it possible to create a liquid crystal display device with high transmittance. realizable.

(Example 5) Example 5 is another example of the present invention in which point defects in the liquid crystal display section of the liquid crystal display device are reduced.

A plurality of pixels of the liquid crystal display section of the liquid crystal display section according to the fifth embodiment of the present invention is shown in FIG. As shown in FIG. 12, the liquid crystal display device of Example 2 has a cross-sectional structure on a line perpendicular to the video signal line DL, and a cross-sectional structure on a line perpendicular to the video signal line DL.
OI2 is the insulating film G1. Protective film PSVI, psV
The scanning signal line GI, the adjacent pixel electrode ITOi, and the electrode 2 are electrically insulated using the Ml film GI and the protective film PSVI, respectively. Therefore, for example, on the same plane (the same insulating film G
Pixel electrode ITO (on I or protection IIPsvl)
The distance of II or ITOI2 in the direction perpendicular to the video signal line DL is greater than the distance between adjacent video signal lines.

In pixels configured in this way, the distance between pixel electrodes on the same plane is large, so the yield rate Ya for point defects is low.
can be significantly improved according to the following exponential formula using Poisson distribution statistics.

Ya=exp (−D−LD/LN)XIO○(%) Here, D is the point defect failure rate when using the conventional structure shown in FIG. The distance between electrodes indicates the distance between pixel electrodes on the same plane in the actual LNN example.

As an example, an active matrix liquid crystal display device with a diagonal of 10.4 inches and 1920 video signal lines in the horizontal direction (distance between II3i1 matching video signal lines is 110 (μm)) and 480 scanning signal lines. If the distance LD between adjacent pixel electrodes in the conventional structure shown in FIG. 2 is 20 (μm) and a liquid crystal display device is manufactured using the same dimensional rules as in the conventional structure, LN will be 130 (μm). In this case, the defect rate of the conventional structure is 0.4 (yield Ya = 60%), 0.2 (
Yield Ya=80%), the point defect yield Y of this example is
a is 94% and 97%, respectively, which can be significantly improved compared to the conventional structure.

Note that as shown in FIG. 11, the pixel electrodes I on the same plane
T○11 or ITOI:2 also has the characteristic that point defects can be further reduced with respect to the scanning signal line GL since the distance between adjacent scanning electrodes on the same plane is greater than the distance between adjacent scanning electrodes.

〔Effect of the invention〕

As explained above, according to the embodiment of the present invention, the short circuit between the pixel electrodes that was formed between the video signal lines in the case of no countermeasures is now formed after the video signal lines are covered with a protective film. Short-circuit strips between pixel electrodes formed between the scanning signal lines due to differences in signal lines and protective films, or when no countermeasures are taken
Although the rT was good, it remained as a defect due to a step in the anodic oxide film formed by anodizing the scanning signal line material on the scanning signal line.
oz cutting and because the distance between the pixel electrodes ITO adjacent to the video signal line in the vertical direction is greater than the distance between adjacent video signal lines, this has the effect of significantly reducing point defects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of one pixel of a liquid crystal display section of an active matrix type liquid crystal display device according to a first embodiment of the present invention, and this figure shows the relationship between the video signal line in the plan view of the main part of FIG. The part cut along the ■-■ cutting line in the cross-sectional view in the right angle direction, the second
The figure shows a cross-sectional view of a conventional structure, Figure 3 shows the cutting rate of indium tin oxide with respect to a step, and Figure 4 shows one pixel of the liquid crystal surface of an active matrix type liquid crystal display device according to Embodiment 1 of the present invention. A plan view of the main part, Figure 5 is a sectional view including the thin film transistor taken along the section line ■-■ in Figure 4, and Figure 6 is a cross-sectional view taken along the line ■-■ in Figure 4. A cross-sectional view including a capacitive element. FIG. 7 is an equivalent circuit diagram showing a liquid crystal display section of an active matrix type liquid crystal display device, and FIG. 8 is a second embodiment of the present invention.
FIG. 9 is a cross-sectional view taken along a vertical line of the video signal line of the liquid crystal display section of the active matrix liquid crystal display device according to the third embodiment of the present invention. FIG. cross-section on the perpendicular line,
FIG. 10 is a sectional view taken along a vertical line of the scanning signal line of the liquid crystal display section of an active matrix type liquid crystal display device according to a fourth embodiment of the present invention, and FIG. 11 is a cross-sectional view of an active matrix type liquid crystal display device according to a fifth embodiment of the present invention. FIG. 12 is a plan view when a plurality of pixels of the liquid crystal display section of the liquid crystal display IT are arranged.
FIG. 2 is a cross-sectional view taken along the line I-1 in FIG. 1 in a direction perpendicular to the video signal line. SUB: Transparent glass substrate, OL, scanning signal line, DL
...Video signal line, GI...insulating film, GT...gate electrode, SD...source electrode, psv...protective film, L
C. Liquid crystal. TPT...thin film transistor, ITO...transparent electrode,
d Conductive film, Cadd...retention capacitor element, A○...anodic oxide film, Cpix/liquid crystal capacitor (numerical subscripts after letters are omitted).

Claims (1)

[Claims] 1. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is in contact with the gate electrode of the thin film transistor, and the video signal line is in contact with the drain electrode of the thin film transistor. In a liquid crystal display device in which a unit pixel is formed in a matrix shape on a transparent substrate and has a function of driving a liquid crystal by a pixel electrode that is in contact with the source electrode of the thin film transistor, a predetermined pixel is formed on a video signal line having a predetermined thickness. A first insulating film having a thickness of A liquid crystal display device characterized in that it is formed on a film. 2. The liquid crystal display device according to claim 1, wherein the video signal line has a thickness of 3000 Å or more. 3. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is in contact with the gate electrode of the thin film transistor, the video signal line is in contact with the drain electrode of the thin film transistor, and the thin film transistor is in contact with the gate electrode of the thin film transistor. In a method of manufacturing a liquid crystal display device in which unit pixels having a function of driving liquid crystal by a pixel electrode in contact with a source electrode are formed in a matrix shape on a transparent substrate, a video signal line, a pixel deposited on the video signal line, etc. Manufacturing of a liquid crystal display device characterized in that the first insulating film and the transparent pixel electrode formed on the first insulating film are formed in the following order: a video signal line, a first insulating film, and a transparent pixel electrode. Method. 4. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is in contact with the gate electrode of the thin film transistor, the video signal line is in contact with the drain electrode of the thin film transistor, and the thin film transistor is in contact with the gate electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having the function of driving liquid crystal by a pixel electrode in contact with a source electrode are formed in a matrix shape on a transparent substrate, a first pixel of a predetermined thickness is placed on a video signal line having a predetermined thickness. an insulating film is formed, and the transparent pixel electrode is etched away at least on the first insulating film other than the area occupied by the video signal line on the first insulating film deposited on the video signal line. A liquid crystal display device characterized in that the liquid crystal display device is formed in a region where 5. In claim 4, the transparent pixel electrode is etched away on the first insulating film deposited on the video signal line other than the area occupied by the video signal line. A liquid crystal display device characterized in that a liquid crystal display device is formed only in a region where 6. The liquid crystal display device according to claim 4 or 5, wherein the first insulating film from which a portion is removed has a thickness of 3000 Å or more. 7. The liquid crystal display device according to claim 4 or 5, wherein both the video signal line and the first insulating film from which a portion thereof is removed have a thickness of 3000 Å or more. 8. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with the gate electrode of the thin film transistor, the video signal line is contacted with the drain electrode of the thin film transistor, and the thin film transistor is connected to the gate electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode are formed in a matrix shape on a transparent substrate, the above scanning signal lines excluding the first and last of a plurality of scanning signal lines exist. Anodic oxidation in which pixel electrodes adjacent to the scanning signal line except the first and last scanning signal lines are formed by anodic oxidation of the scanning electrode material in a cross-sectional structure in a vertical direction on a plane. A liquid crystal display device characterized in that a gate insulating film of a thin film transistor is provided in a portion other than at least one step of the film and in a portion other than an opening region through which light passes on the pixel electrode. 9. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is contacted with the gate electrode of the thin film transistor, the video signal line is contacted with the drain electrode of the thin film transistor, and the thin film transistor is connected to the gate electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode are formed in a matrix shape on a transparent substrate, the above scanning signal lines excluding the first and last of a plurality of scanning signal lines exist. A transparent pixel electrode adjacent to the scanning signal line except for the first and last scanning signal lines is formed by anodizing the scanning electrode material in a vertical cross-sectional structure on a plane. 1. A liquid crystal display device comprising: a gate insulating film of a thin film transistor formed on a portion other than the anodic oxide film and provided on the pixel electrode other than the opening region through which light passes. 10. The scanning signal line, the anodic oxide film formed on the scanning signal line, and the pixel electrode in contact with the source electrode are formed in the order of forming the scanning signal line, the anodic oxide film, and the pixel electrode,
A method for manufacturing a liquid crystal display device, characterized in that the liquid crystal display device is manufactured in a process that does not include a manufacturing process for other insulating films during the manufacturing process for an anodic oxide film and a pixel electrode. 11. The liquid crystal display device according to claim 8 or 9, wherein both the upper and lower electrodes forming the storage capacitor are formed of an opaque electrode material. 12. The liquid crystal display device according to claim 8 or 9, wherein the upper electrode forming the storage capacitor is formed of a pixel electrode. 13. The liquid crystal display device according to claim 8 or 9, wherein the total thickness of the scanning signal line and the anodic oxide film is 3000 Å or more. 14. A thin film transistor is formed at the intersection of one scanning signal line and one video signal line, the scanning signal line is in contact with the gate electrode of the thin film transistor, the video signal line is in contact with the drain electrode of the thin film transistor, and the thin film transistor is in contact with the gate electrode of the thin film transistor. In a liquid crystal display device in which unit pixels having a function of driving a liquid crystal by a pixel electrode in contact with a source electrode are formed in a matrix shape on a transparent substrate, the above-mentioned video signal lines excluding the first and last of a plurality of video signal lines exist. In a vertical cross-sectional structure of the video signal line on a plane, pixel electrodes adjacent to the video signal line except for the first and last video signal lines are connected to a transparent substrate or a first insulator. A video signal line formed on the first insulating film is formed on the first insulating film, and the video signal line is formed on the first insulating film, and the other pixel electrode is formed on the video signal line. A liquid crystal display device characterized in that the liquid crystal display device is formed on a second insulating film. 15. The liquid crystal display device according to claim 14, wherein the pixel electrode is formed on a portion other than the video signal line. 16. In claim 14, the scanning signal lines excluding the first and last of the plurality of scanning signal lines are arranged in a cross-sectional structure in a vertical direction on a plane, and the scanning signal lines excluding the first and last are One of the pixel electrodes adjacent to the signal line is formed on a transparent substrate or a first insulating film, and the scanning signal line is formed at approximately the midpoint on the plane with the other pixel electrode. A liquid crystal display device, wherein the pixel electrode is formed on the first insulating film, and the other pixel electrode is formed on the second insulating film formed on the scanning signal line.