JP2000338525A - Matrix array substrate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make significantly decreasable the number of production processes and the production cost, to make formable the columnar spacer with more uniform height of projections, and to make improvable the stability of the product quality, in a matrix array substrate equipped with a columnar spacer and a flattening film and in a production method of the substrate. SOLUTION: After a TFT1 and a metal wiring pattern are formed, an acrylic resin 21, 22 is first made to have uniform height by coating. Then, a resist is formed on the region where the TFT1 is present, and subjected to reactive ion etching using a mixture gas of CF4 gas and oxygen gas (with 10% volume concn. of CF4). Under the aforementioned etching conditions, an etching-resistant deposit is formed except for the region near the spacer projection 2. Thereby, the thickness of the resin layer is reduced by etching to form a flattening film 25 in forming the spacer projection 2, and a through hole 23 as a surrounding groove is formed around the spacer projection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a matrix array substrate used for a flat panel display device such as a liquid crystal display device and a method of manufacturing the same. In particular, the present invention relates to a matrix array substrate provided with columnar spacer protrusions and a flattening film.

[0002]

2. Description of the Related Art In recent years, flat-panel display devices replacing CRT displays have been actively developed. Among them, liquid crystal display devices have attracted particular attention because of their advantages such as light weight, thinness, low power consumption, and low eye fatigue. I am collecting.

For example, an active matrix type liquid crystal display device in which a switch element is disposed for each display pixel will be described as an example. The active matrix type liquid crystal display device has a configuration in which a liquid crystal layer is held between an array substrate and a counter substrate via an alignment film. In the array substrate, a plurality of signal lines and scanning lines are arranged in a grid on a transparent insulating substrate such as glass or quartz, and amorphous silicon (hereinafter abbreviated as a-Si: H) is provided at each intersection. (Hereinafter abbreviated as TFT) using a semiconductor thin film of
Is connected. The gate electrode of the TFT is electrically connected to the scanning line, the drain electrode is electrically connected to the signal line, and the source electrode is electrically connected to a transparent conductive material constituting the pixel electrode, for example, ITO (Indium-Tin-Oxide). Have been.

The counter substrate has a counter electrode made of ITO disposed on a transparent insulating substrate such as glass.

Here, if a color display is to be realized, a color filter layer is disposed on a counter substrate or an array substrate at least at a position corresponding to a pixel electrode. In addition, a number of spacers are arranged between the two substrates to keep the distance between the substrates constant.

[0006] As a spacer, it has been the most general practice to previously disperse spheres made of resin or silica and having a uniform diameter on one of the substrates. However, the non-fixing and scattering spacers (spherical spacers) have problems such as damage to the alignment film due to the movement of the spacers and deterioration in display quality due to light leakage from the spacers.

For this reason, recently, fixed columnar spacers have been used. This columnar spacer is formed by (1) forming a flattening film, or forming a colored pattern layer by photolithography, providing a thick resin layer by coating, etc., and leaving only specific places by photolithography. , Or (2)
By repeating the coating of the resin layer containing the pigment and patterning by photolithography three times, the red,
A method has been used in which blue and green colored pattern layers are formed, and these colored pattern layers are superimposed at specific locations.

[0008]

However, in producing a columnar spacer, in the method of repeating the patterning by photolithography and overlapping the resin layers as described above, it is necessary to sufficiently control the projection height of the columnar spacer. It was difficult. Further, since the coating step and the patterning step need to be repeated, it has been difficult to reduce the manufacturing cost of the matrix array substrate and to improve the reliability of the manufacturing step.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a matrix array substrate provided with a columnar spacer and a flattening film, and a method of manufacturing the same, the number of manufacturing steps and manufacturing cost can be significantly reduced. Another object of the present invention is to provide a columnar spacer in which the height of protrusions can be made more uniform, thereby improving the quality stability of a product.

[0010]

According to a first aspect of the present invention, there are provided a plurality of pixel electrodes arranged in a matrix in an image display area, a switching element arranged for each pixel electrode, and a switching element. A plurality of signal lines for supplying a video signal to a pixel electrode through the pixel electrode, a plurality of scanning lines arranged to be substantially orthogonal to the signal line and driving a switching operation of a switching element, and at least the pixel electrode In a matrix array substrate for a flat panel display device, comprising a flattening film disposed at a position and a spacer projection, the spacer projection includes the same coating layer or deposition layer as the flattening film, and the switching element It is required that through holes in the planarizing film and the spacer protrusions for electrically connecting the pixel electrodes are formed in the same step. And butterflies.

With the above configuration, the number of manufacturing steps and manufacturing cost can be significantly reduced. In addition, the heights of the protrusions of the columnar spacers can be made more uniform, thereby improving the quality stability of the product.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG.

First, the structure of a matrix array substrate according to an embodiment will be described with reference to FIGS.

In the array substrate 3, a glass substrate 18
Above, 2400 signal lines 11 composed of an upper metal wiring pattern and 600 scanning lines 13 composed of a lower metal wiring pattern are arranged in a grid via an insulating film 14 (gate insulating film). A pixel electrode 3 made of, for example, ITO (Indium-Tin-Oxide) is disposed as a transparent conductive film in a region corresponding to each grid of the lattice. Then, a TFT 1 is disposed as a switching element for controlling each pixel electrode at one corner of each grid of the grid. The gate electrode of the TFT 1 is electrically connected to the scanning line, the drain electrode is electrically connected to the signal line, and the source electrode is electrically connected to the pixel electrode.

In the example shown in the figure, the TFT 1 is of a back channel cut type, and the semiconductor layer 19 of the TFT 1 is such that the upper layer portion of the amorphous silicon layer is doped with phosphorus. In the lower metal wiring pattern, auxiliary capacitance lines 17 (Cs lines) extending substantially parallel to the two adjacent scanning lines are arranged between two adjacent scanning lines.

As shown in FIG. 1, a single flattening film 25 having a uniform height from the glass substrate 18 to the upper surface except for the TFT 1 is disposed. The flattening film 25 includes a colored first resin layer 21 (color filter layer) and a colorless and transparent second resin layer (protective film) covering the first resin layer 21.
The first resin layer 21 is colored with red, blue and green dyes to form a colored pattern (color filter) for each predetermined region.

On the other hand, as shown in FIG. 1, a columnar spacer projection made of the same material as that of the flattening film 25 by the same process is disposed at the location of the TFT 1. The spacer protrusions are composed of the first resin layer 21 and the second resin layer as in the case of the flattening film 25, and the height of the upper surface of the first resin layer 21 in the spacer protrusions is exactly the same as that of the flattening film 25. It is. Therefore, the thickness of the second resin layer is largely different between the spacer protrusion and the flattening film 25.

At the boundary between the spacer protrusion and the region of the flattening film 25, that is, at the position surrounding the spacer protrusion from four sides, a circumferential groove-like (groove-like) through hole penetrating the first and second resin layers is provided. A hall is provided.

As shown in FIG. 1, the first resin layer 2
1 is covered with a passivation film 15.
Are provided, and a through hole for exposing the upper surface of the source electrode 12 is provided in advance at a location where the circumferential groove-shaped through hole 23 crosses over the source electrode 12. That is, the first and second resin layers 2 are formed on the source electrode 12.
A straight groove-shaped through-hole 16 penetrating through the passivation film 15 is formed.

As shown in FIG. 1, the pixel electrode 3 is formed on the upper surface of the flattening film 25, and has a through hole 16 having a linear groove shape.
Is directly connected to the upper surface of the source electrode 12 by the portion covering the inner surface of the source electrode 12, and is electrically conductive. Further, as shown in FIG. 2, each pixel electrode 3 is arranged so as to overlap with two scanning lines and two signal lines surrounding it, and no light leakage occurs between them. That is, the planarizing film 2
Since the pixel electrode 3 is arranged on the pixel 5, there is no need to arrange a black matrix surrounding the pixel electrode 3, and the aperture ratio can be kept high.

Next, the main part of the manufacturing method will be described with reference to FIGS.

(1) Scan lines, signal lines, and TFTs 1
Is formed, and a passivation film 15 made of an inorganic insulating film such as a silicon nitride film is deposited thereon so as to cover them, and the passivation film 1 is formed on the source electrode 12.
5 are formed.

(2) First, on the passivation film 15,
Forming a first uniform resin layer 21 by coating;
Subsequently, the resin layer 21 is dyed to form a colored pattern. More specifically, first, an acrylic copolymer resin containing a photosensitive agent is applied by a spinner to about 1 μm. Thereafter, for example, red (R), green (G), and blue (B) dyes are ejected for each predetermined region by an ink-jet drawing method to form a colored pattern that is painted in three colors. .

(3) Next, in order to form the second resin layer 22, an acrylic resin containing a photosensitizer (Optomer SS6699G manufactured by JSR) is uniformly coated with a spinner so that the film thickness after drying and curing is about 5 μm. And cured by light irradiation. Then, annealing is performed by applying heat for stability.

(4) A resist 4 (OFPR5000 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied on the second resin layer 22 with a thickness of several μm by a spinner, and is applied only to the location of the TFT 1, that is, the location where the spacer projection 2 is formed. Patterning was performed so as to leave. The state after this patterning is shown in FIG.

(5) The resin layers 21 and 22 thus obtained
In response, reactive ion etching equipment (RIE equipment,
Dry etch by ULVAC CSE-1210)
Was performed. At this time, the gas introduced into the etching chamber
So, CF₄Introducing flow rate of gas and oxygen gas (scc
m) is set at 45: 5 to obtain a mixed gas (CF
₄Of 10%).

FIG. 4 shows a state immediately after the start of etching.

By the reaction between the components of the second resin layer 22 and the etching gas (mixed gas of CF ₄ and oxygen), a resist deposit 5 having an etching resistance to this etching agent is formed on the resin layer. Formed. For this reason, as the resist deposit 5 is deposited, the etching rate decreases. On the other hand, at the time of etching, the upper surface of the resist 4 is slightly etched, and particularly, the upper corner of the edge of the resist 4 is removed as shown in the figure. Due to the action of the components derived from the resist 4 and other actions, the resist deposit 5 is not formed on the upper surface of the resin layer 22 at a location close to the resist 4. Therefore, the etching of the resin layer 22 progresses faster at a portion close to the resist 4 than at other portions, and as shown in FIG.
The peripheral groove 23a is formed.

In order to form such a circumferential groove 23a, it is desirable to use, for example, an oxygen gas or a mixed gas of CF ₄ and oxygen having a volume concentration of CF ₄ gas of 25% or less. If the volume concentration of the CF ₄ gas exceeds 25%, the resist deposit 5 is not easily formed, and it is difficult to obtain a necessary etching selectivity (etching rate ratio). The volume concentration of CF ₄ gas in the mixed gas for etching is preferably 5 to 15%.

FIG. 5 shows a state at the end of the etching.

As shown in the figure, a circumferential groove-shaped through hole penetrating the first and second resin layers is formed on the four circumferences of the spacer protrusion 2, and except for the vicinity of the spacer protrusion, the through hole of the second resin layer is formed. The thickness is reduced, and a flattening film 25 having a uniform height is formed. After the etching is completed, the resist 4 and the resist deposit 5 are removed by using a chemical solution or another etching gas.

(6) Finally, a volume and patterning step for forming a pixel electrode is performed. Thus, FIG.
2 are completed.

According to the embodiment described above, the columnar spacer projection 2 and the groove-like through-hole are formed by a single patterning step, that is, by a step of one cycle of resist layer coating → lithography → development → etching → resist removal. The hole 23 and the flattening film 25 covering substantially the entire area other than these portions can be formed at the same time. Therefore, the number of manufacturing steps can be significantly reduced, and the manufacturing cost can be significantly reduced. Further, since the thickness of the columnar spacer projection 2 can be determined by only one resin coating, the height of the columnar spacer can be made uniform, and the quality stability of the manufactured matrix array substrate can be improved. be able to.

In the above embodiment, the first resin layer 21 constituting the flattening film 25 has been described as forming a colored pattern layer. However, even when the colored pattern is not provided on the matrix array substrate, the first resin layer 21 is substantially formed. Similar effects can be obtained.

[0035]

As described above, in the matrix array substrate provided with the columnar spacers and the flattening film and the manufacturing method thereof, the number of manufacturing steps and the manufacturing cost can be greatly reduced. In addition, the heights of the protrusions of the columnar spacers can be made more uniform, thereby improving the quality stability of the product.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view schematically showing a laminated structure of a matrix array substrate according to an embodiment. It is a cut surface of the part of XX 'of FIG.

FIG. 2 is a partial plan view schematically illustrating a wiring structure of a pixel portion of a matrix array substrate according to an example.

FIG. 3 is a partial longitudinal sectional view corresponding to FIG. 1, showing a state where a resist pattern is arranged on a uniform resin layer for providing a flattening film and columnar spacer protrusions.

FIG. 4 is a partial longitudinal sectional view corresponding to FIGS. 1 and 3, showing a state immediately after the start of etching.

FIG. 5 is a partial longitudinal sectional view corresponding to FIGS. 1 and 3, showing a state immediately after the completion of etching.

[Description of Signs] 1 TFT 10 Laminated structure before forming resin layer 12 Source electrode 15 Passivation film 16 Through hole of passivation film 2 Spacer protrusion 21 First resin layer (color filter layer) 22 Second resin layer (Protective film) 22a) second resin layer 23 whose thickness is reduced by etching 23 peripheral groove-shaped through hole 25 flattening film 3 pixel electrode

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuge Omoto 7-1 Nisshin-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in Toshiba Electronics Engineering Co., Ltd. (Reference) 2H048 BA64 BB02 BB03 BB28 BB42 2H089 LA09 NA14 NA15 NA17 NA24 PA05 QA12 QA14 TA09 TA12 2H090 HA03 HB07X HC05 HC12 HC19 HD03 LA02 LA04 LA15 2H091 FA02Y FB04 FC05 FC23 FC26 FD04 GA07 GA08 GA13 GA16 LA12 LA15 LA20 2H092 JA24 JA46 JB57 JB58 KA05 KB26 MA10 MA19 MA37 NA19 NA27

Claims (6)

[Claims] 1. A plurality of pixel electrodes arranged in a matrix in an image display area, a switching element arranged for each pixel electrode, and a plurality of pixels for supplying a video signal to the pixel electrode via the switching element. A plurality of scanning lines arranged to be substantially orthogonal to the signal line and driving a switching operation of a switching element, and a flattening film disposed at least between the pixel electrode and the switching element. A matrix array substrate for a flat panel display device, comprising: a spacer projection, wherein the spacer projection includes the same coating layer or deposition layer as the planarizing film, and electrically connects the switching element and the pixel electrode. Wherein the through hole of the planarizing film and the spacer projection are formed in the same step. Rei board. 2. A plurality of pixel electrodes arranged in a matrix in an image display area, a switching element arranged for each pixel electrode, and a plurality of pixels for supplying a video signal to the pixel electrode via the switching element. A plurality of scanning lines arranged to be substantially orthogonal to the signal line and driving a switching operation of a switching element, and a flattening film disposed at least between the pixel electrode and the switching element. A matrix array substrate for a flat panel display device, comprising: a spacer projection; and a groove-shaped through-hole penetrating the flattening film is formed at a position surrounding the spacer projection. A matrix array substrate, wherein a switching element and the pixel electrode are electrically connected. 3. The matrix array substrate according to claim 1, wherein the flattening film includes a colored layer and a non-colored layer covering the colored layer. 4. A series of steps for forming a plurality of scanning lines, a plurality of signal lines substantially orthogonal to the scanning lines, and a switching element disposed in the vicinity of each of the intersections, and at least covering the switching element. Forming a layer forming a flattening film by coating or depositing; forming a through hole in the flat film by etching on a terminal portion of the switching element; and forming a matrix in an image display area in a matrix. Forming a pixel electrode electrically connected to the switching element through the through hole; and forming the through hole by etching. Matrix array characterized in that spacer projections are formed from a layer including a layer forming a passivation film Method of manufacturing the plate. 5. The method according to claim 1, wherein the flat film is made of an acrylic resin, and the etching is performed using oxygen gas or CF.₄Concentration 2
5% by volume or less of CF ₄Using a mixed gas of
5. The method according to claim 4, wherein the lithographic etching is performed.
A method for manufacturing a matrix array substrate. 6. The step of forming a layer forming the planarizing film,
Further, the method includes a step of forming a first resin layer by coating, a step of dyeing the first resin layer to form a colored pattern, and a step of forming a second resin layer thereon by coating. The method for manufacturing a matrix array substrate according to claim 4, wherein: