KR101826033B1 - Method for planarizing substrate and method for manufacturing color filter substrate - Google Patents

Abstract

The present invention relates to a method of planarizing a substrate and a method of manufacturing a color filter substrate.
A method of manufacturing a color filter substrate according to the present invention includes the steps of: forming a black matrix on the boundary of pixel regions on a first substrate; forming a color filter on the edge of the black matrix, Forming an organic insulating layer on the black matrix and the color filter; forming a first substrate on which the organic insulating layer is formed; and a second substrate on the first substrate, Placing the vacuum chamber in a vacuum state and allowing the first substrate and the second substrate to adhere to each other by free dropping the second substrate, And the second substrate is a high-polishing substrate having a higher flatness value than the first substrate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of planarizing a substrate and a method of manufacturing a color filter substrate,

The present invention relates to a method of planarizing a substrate and a method of manufacturing a color filter substrate.

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a high contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal layer is sandwiched between two adjacent substrates through an intervening liquid crystal layer as an essential component. At the back of the liquid crystal panel, a backlight ) Units.

Since the structure of the liquid crystal molecules in the liquid crystal layer is narrow and long, it has a directional arrangement, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

That is, when the arrangement of the liquid crystal molecules is changed by using the electric field, the light is refracted in the arrangement direction of the liquid crystal molecules due to the optical anisotropy of the liquid crystal, and the image can be displayed.

The liquid crystal panel is configured such that the first substrate and the second substrate are bonded to each other with the liquid crystal layer interposed therebetween as described above.

Here, assuming that the active matrix method is currently widely applied, a plurality of gate lines and data lines cross each other on a first substrate called a lower substrate or an array substrate, pixels are defined, and one-to-one correspondence with transparent pixel electrodes formed on each pixel And an array layer including a thin film transistor (TFT) is provided at each intersection to be connected.

The second substrate, which is called an upper substrate or a color filter substrate, is provided with color filters of red (R), green (G), and blue (B) A color filter layer including a black matrix for covering non-display elements such as lines and data lines and thin film transistors is provided.

The first substrate and the second substrate are formed on a glass substrate. The glass substrate is subjected to a surface treatment so as to planarize the surface of the glass substrate through a polishing process.

At this time, the polishing process for the surface treatment of the substrate is performed by polishing the substrate through the polishing pad of the surface polishing machine after the polishing liquid is sprayed on the substrate. Since the polishing process must be repeated several times with the polishing pad being replaced, There is a problem.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a correlation between a polishing time for a surface treatment of a substrate and a flatness of the substrate. FIG. Here, the flatness is a value according to the inspection standard of AGC (Asahi Glass Company).

Referring to FIG. 1, the planarization value of the substrate is represented by AGC (Asahi Glass Company) value, which is based on Asahi Glass Co., according to the polishing time according to the polishing process. It is known that the flatness value decreases as the polishing time becomes longer .

Generally, when the flatness value is less than 0.88 articles (articles), it corresponds to a high-abrasive glass substrate, and when the flatness value is more than 0.88 articles, it corresponds to a low-abrasive glass substrate.

That is, the longer the polishing time, the better the flatness of the substrate, and the lower the flatness value, the higher the abrasive glass substrate.

Here, since the low-abrasive glass substrate has an advantage that the production time and manufacturing cost can be reduced because the polishing time is shorter than that of the high-abrasive glass substrate, there is a problem that a fine stripe- There is a problem.

On the other hand, in the case of a color filter substrate provided with a color filter layer, an overcoat layer of a thermosetting material may be coated on the color filter layer to planarize the substrate.

However, since the overcoat layer can flatten a step of a narrow range of about 100 mu m, a low-abrasive glass substrate is bent in a wide range of several millimeters, so that even if an overcoat layer is formed, There is a problem that it is formed along the curvature of the unary.

That is, the step due to the unevenness of the unripe is difficult to planarize with the overcoat layer.

FIG. 2 is a view showing the color filter substrate on which the unevenness is generated, and FIG. 3 is a cross-sectional view taken along line II-II 'of FIG.

As shown in Figs. 2 and 3, the unipa 20a forms a fine or irregular fine bend along the transverse or longitudinal surface of the color filter substrate 20.

Here, the color filter substrate 20 may be divided into a plurality of subglas substrates by a scribing and cutting process after a color filter layer is formed by a photolithography process including deposition, exposure, development, and etching processes on a glass substrate .

The unevenness 20a can be widely formed on the surface of the color filter substrate 20 having a certain thickness t in the range of several micrometers to millimeters, which is a problem.

For example, when the pitch distance L of the unevenness 20a is 1 to 10 mm or more, it is difficult to planarize.

On the other hand, although not shown in the drawing, the cross-sectional shape of the universe 20a may be generated from the surface of the color filter substrate 20 in a protruding pattern such as a triangular shape, an elliptical shape, or a semicircular shape.

That is, when the unevenness 20a is viewed on the surface of the generated surface, a pattern protruding along the exposed surface of the color filter substrate 20 may appear repeatedly.

When a liquid crystal display device is fabricated with the color filter substrate 20 having the veneer 20a as described above, it is manifested as a linear smear in the inspection process. Such smear causes luminance unevenness and causes deterioration of image quality There is a problem.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of flattening a substrate which does not cause unevenness while using a low-abrasive glass substrate which can reduce process time and process cost.

According to an aspect of the present invention, there is provided a method of manufacturing a color filter substrate, including: forming a black matrix on a boundary between pixel regions on a first substrate; Forming a color filter corresponding to each of the pixel regions so that an edge overlaps the edge of the black matrix; Forming an organic insulating layer on the black matrix and the color filter; A first substrate on which the organic insulating film is formed, and a second substrate disposed on the first substrate in a vacuum chamber so as to face the second substrate with a predetermined gap therebetween; Making the interior of the vacuum chamber in a vacuum state and allowing the first substrate and the second substrate to adhere to each other by freely dropping the second substrate; And the second substrate is a high-polishing substrate having a higher flatness value than the first substrate.

And the organic insulating film is formed of a photocurable resin.

And forming the common electrode.

And discharging the first and second substrates from the vacuum chamber in the steps described above.

The method may further include separating the second substrate from the first and second substrates that are joined together.

A method for planarizing a substrate according to the present invention includes the steps of: placing a first substrate, which is an object to be planarized, in a vacuum chamber so that the second substrate faces the first substrate with a predetermined gap therebetween, To a vacuum state; Allowing the second substrate to fall freely so that the first substrate and the second substrate are bonded together; Wherein the first substrate comprises red, green, and blue color filters and a black matrix, and the overcoat layer is coated on top of the color filter and the black matrix, Is a high-polishing substrate having a higher flatness value than the first substrate.

As described above, according to the present invention, after the color filter substrate on which the low-abrasive glass substrate is base is placed in the vacuum chamber, the high-abrasive glass substrate is freely dropped on the upper surface thereof to planarize the surface of the color filter substrate to prevent unevenness .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a correlation between a polishing time for a surface treatment of a substrate and a flatness of the substrate. FIG.
2 is a view showing a glass substrate on which unevenness is generated.
3 is a cross-sectional view taken along the line II-II 'of FIG. 2;
4 is a cross-sectional view schematically showing a transverse electric field type liquid crystal panel according to a preferred embodiment of the present invention.
5 is a schematic view of a vacuum chamber according to a preferred embodiment of the present invention.
6 is a flow chart illustrating a method of planarizing a substrate according to a preferred embodiment of the present invention.
7A to 7C are views for explaining a method of planarizing a substrate according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

4 is a cross-sectional view schematically showing a transverse electric field type liquid crystal panel according to a preferred embodiment of the present invention.

4, the transverse electric field type liquid crystal panel 100 includes an array substrate 110 and a color filter substrate 140 which are adhered to each other with a certain cell gap, And a liquid crystal layer (LC) interposed in a spaced-apart space of the liquid crystal layer (140).

Here, under the assumption of the active matrix method, the array substrate 114, which is usually referred to as a lower substrate, is provided in the array substrate 110 through an array process.

The array layer 114 includes a plurality of gate wirings (not shown) and data wirings (not shown) arranged on the first glass substrate 112 and defining a plurality of pixel regions P, A thin film transistor (TFT) T, a common electrode 130, and a pixel electrode 132 are formed for each pixel region P of the liquid crystal display device.

The thin film transistor T is formed at a point of intersection of a plurality of gate wirings (not shown) and data wirings (not shown) and connected in a one-to-one correspondence with the pixel electrodes 132 provided in the pixel regions P respectively.

The thin film transistor T includes a gate electrode 114 connected to a gate wiring (not shown), a semiconductor layer 118 over the gate electrode 114, And includes a source electrode 120 and a drain electrode 122 which are formed.

A color filter layer 144, which is also called an upper substrate, is provided on the color filter substrate 140 facing the array substrate 110 on the second glass substrate 142.

The color filter layer 144 includes a red color filter 146a, a green color filter 146b, and a blue color filter 146b, which are sequentially and repeatedly arranged corresponding to the pixel regions P, And a black matrix (not shown) for framing each pixel region P so as to cover the non-display regions of the gate wiring (not shown), the data wiring (not shown) and the thin film transistor T, ) 145 are formed.

Although not shown, in order to prevent leakage of the liquid crystal layer LC interposed between the array substrate 110 and the color filter substrate 140, a gap between the array substrate 110 and the color filter substrate 140 The array substrate 110 and the color filter substrate 140 are bonded together by forming a seal pattern (not shown) printed along the outermost edge of the liquid crystal panel 100 to form the liquid crystal panel 100.

First and second polarizing plates (not shown) are provided on the outer surfaces of the array substrate 110 and the color filter substrate 140, respectively. A backlight including a light source is disposed on the back surface of the liquid crystal panel 100, light unit (not shown).

The ON / OFF signals of the thin film transistor T are sequentially scanned and applied to the gate wiring (not shown) of the liquid crystal panel 100 by supplying the light by the backlight unit (not shown) When an image signal of a data line (not shown) is transmitted to the pixel electrode 132 of the pixel region P, liquid crystal molecules therebetween are driven by the horizontal electric field 135 between the common electrode 130 and the pixel electrode 132 And various images can be displayed by the change of the light transmittance.

Meanwhile, the color filter substrate 140 can be formed with a color filter layer 144 by a pigment dispersion method, a dyeing method, an electrodeposition method, or a thermal transfer method.

Here, as an example of the above methods, the manufacturing process of the color filter substrate 140 using the pigment dispersion method will be described on the assumption that the low-abrasive glass substrate is used as the base substrate.

A metal material or a resin is deposited on the entire surface of the substrate on the second glass substrate 142 as a low-abrasive glass substrate and then patterned through a mask process to form a black matrix 145 (corresponding to each pixel region) ).

A red resist such as red, green, or blue is coated on the second glass substrate 142 on which the black matrix 145 is formed by a spin coating apparatus or a bar coating apparatus And is applied to the entire surface of the second glass substrate 142 to form a red resist layer.

Thereafter, an exposure mask composed of a transmissive region for transmitting light and a shielding region for blocking transmission of light is positioned above the red resist layer, and then exposure is performed.

When the exposed red resist layer is developed, a red color filter 146a whose edges overlap with the edges of the black matrix 145 is formed.

The green color filter 146 and the blue color filter are formed in the same manner as the method of forming the red color filter 146a, with the edges overlapping with the edges of the black matrix 145.

Next, an organic insulating material for protection and level difference compensation is applied to the upper portion of the black matrix 145 and the red, green, and blue color filters 146a and 146b to form an overcoat Layer. Here, the organic insulating material corresponding to the overcoat layer is a photocurable resin.

In this way, a black matrix 145, red, green and blue color filters 146a and 146b and an overcoat layer (not shown) are formed on the second glass substrate 142, and an overcoat layer (not shown) The color filter substrate 140 can be completed. Since the second glass substrate 142 is a low-abrasive glass substrate, a planarization process for planarizing the substrate must precede the cell process in which the array substrate 110 is bonded to the array substrate 110 .

Hereinafter, the planarization process for planarizing the substrate will be described in detail with reference to the drawings.

FIG. 5 is a schematic view of a vacuum chamber according to a preferred embodiment of the present invention, and FIG. 4 is referred to.

As shown in FIG. 5, the vacuum chamber 200 includes an inlet 210 and first and second substrate supports 220 and 230 corresponding to the upper and lower sides.

Although not shown here, the vacuum chamber 200 preferably further includes a control unit for controlling the transfer unit, the pressure regulator, and the overall system.

The loading port 210 corresponds to a door at the time of loading and unloading the substrate. As shown in the figure, the loading port 210 is opened to allow the substrate to pass through during loading and unloading, and after the loading and unloading, Is closed to maintain the vacuum state.

Each of the first and second substrate supports 220 and 230 serves to fix the substrate.

The first substrate support 220 supports and fixes a first substrate that is seated on top of it.

The second substrate supporting unit 230 is configured to attract and fix a second substrate disposed below the second substrate supporting unit 230, and to drop the second substrate to adhere the second substrate to the first substrate.

Thus, the surface of the second substrate and the surface of the first substrate are brought into close contact with each other.

Here, the first substrate supporting part 220 and the second substrate supporting part 230 are positioned so as to be aligned with each other.

Thereby, it is not necessary to align the first substrate fixed to the first substrate supporting part 220 and the second substrate fixed to the second substrate supporting part 230.

Each of the first and second substrate supports 220 and 230 may include at least one lift pin 212 or 232 for up or down to load and unload the first and second substrates, One.

A plurality of vacuum holes (not shown) are formed on the surfaces of the first and second substrate supports 220 and 230, respectively.

Accordingly, the first and second substrate supporters 220 and 230 suck air through the plurality of vacuum holes (not shown) to fix the first and second substrates by vacuum suction.

Alternatively, each of the first and second substrate supports 220 and 230 supplies air to a plurality of vacuum holes (not shown) to allow the substrate to be separated.

Each of the first and second substrate supporting portions 220 and 230 may further include an antistatic portion (not shown) for preventing electrification.

Here, the substrate is transported by a transfer unit (not shown) at the time of loading and unloading and fixed to the first and second substrate supports 220 and 230 of the vacuum chamber 200, Can be separated and discharged from the supporting portions 220 and 230.

A pressure regulating unit (not shown) is connected to the vacuum chamber 200 through a valve (not shown) to regulate the internal pressure of the vacuum chamber 200 to make the inside of the vacuum chamber 200 a vacuum state .

FIG. 6 is a flowchart illustrating a method of planarizing a substrate according to a preferred embodiment of the present invention. FIGS. 7A to 7C are views for explaining a method of planarizing a substrate according to a preferred embodiment of the present invention, .

6 and 7A, the first substrate 140 and the first substrate 140, which are objects to be planarized, are flattened into the vacuum chamber 200 through the inlet 210 of the vacuum chamber 200 (St1) is inserted into the second substrate 260.

The first substrate 140 and the second substrate 260 may have the same size or a second substrate 260 that is mounted on the first substrate 140 may be formed to have a size larger than that of the first substrate 140 .

The first substrate 140 is a color filter substrate on which a color filter layer 144 is formed on a low-abrasive glass substrate. Although not shown in the figure, a negative electrode having a regular or irregular curvature is formed on the surface.

The second substrate 260 is a highly polished glass substrate having a flatness (AGC) value of less than 0.88 and no unevenness is generated.

The first substrate 140 is provided with a black matrix 145 and red, green and blue color filters 146a, 146b and 146c on the transparent insulating substrate 142, 146c are formed with an overcoat layer 147 for compensating the protection and the step difference.

Here, the black matrix 145 is formed to cover each pixel region (P in FIG. 4) so as to cover a non-display region such as a gate wiring (not shown), a data wiring (not shown), and a thin film transistor As shown in FIG.

The red, green, and blue color filters 146a, 146b, and 146c are formed so as to be sequentially and repeatedly arranged corresponding to each pixel region (P in FIG. 4).

The overcoat layer 147 is coated with a photocurable resin and is preferably in a state before curing.

The color filter substrate is formed by coating the overcoat layer with a thermosetting material and thermally curing the substrate. However, in the present invention, a black matrix and a color filter are formed on a low-abrasive glass substrate And the overcoat layer is coated thereon with a photo-curing resin, and then the substrate is planarized before curing. This will be described in detail later.

The first substrate 140 is disposed such that the overcoat layer 147 is positioned on the front surface of the first substrate 140 and the second substrate 260 is disposed on the first substrate 140 to perform planarization. Are spaced apart at regular intervals.

At this time, the distance between the first substrate 140 and the second substrate 260 located on the first substrate 140 may be about several hundreds of um, which may be about 500 um.

The first substrate 140 is inserted into the vacuum chamber 200 by a first transferring unit and fixed to the upper portion of the first substrate supporting unit 220, (Not shown) into the vacuum chamber 200 and fixed to the lower portion of the second substrate supporting part 230. [

A plurality of vacuum holes (not shown) are formed on the surfaces of the first and second substrate supports 220 and 230 to suck air through the plurality of vacuum holes (not shown) The first substrate 140 and the second substrate 260 are fixed by vacuum-suctioning the second substrates 260, respectively.

The first substrate 140 and the second substrate 260 are disposed to face each other.

When the first substrate 140 and the second substrate 260 are inserted into the vacuum chamber 200, the pressure of the vacuum chamber 200 is adjusted to make the inside of the vacuum chamber 200 to be in a vacuum state.

The degree of vacuum of the vacuum chamber 200 is generally about 50 mTorr or less.

6 and 7B, the second substrate supporter 230 supplies air to a plurality of vacuum holes (not shown) so that the second substrate 260 is heated in a vacuum chamber 200 in a vacuum state (St3) so as to be seated on the upper portion of the first substrate 140.

Thus, as shown in FIG. 7C, the first substrate 140 and the second substrate 260 are bonded to each other (ST5).

At this time, as the second substrate 260, which is positioned at a predetermined distance from the first substrate 140, drops freely from the upper portion of the first substrate 140, the surface of the second substrate 260 is separated from the first substrate 140 140).

Accordingly, the surface of the first substrate 140 is planarized by the second substrate 260, and the flatness is improved, whereby the unevenness can be solved.

Then, the first substrate 140 and the second substrate 260, which are bonded together in the vacuum chamber 200, are irradiated with UV light of a predetermined intensity to perform photo-curing on the overcoat layer 147 (st7) .

The first substrate 140 and the second substrate 260 on which light curing has progressed are discharged out of the vacuum chamber 200 and separated from each other or separated from each other in the vacuum chamber 200 and then discharged out of the vacuum chamber 200 (St9).

As the second substrate 260 which is a highly polished glass substrate drops freely and is seated on the first substrate 140, the surface flatness of the first substrate 140 is reduced by the second substrate 260, 2 substrate 260, the unevenness can be solved.

In addition, as the free fall occurs, damage to the substrate and the substrate due to uneven pressurization, which is a disadvantage of the pressing method by the physical force, can be eliminated. Further, the flattening process can be performed by an easier method, Life and reliability can be improved.

As a result, it is possible to manufacture a color filter substrate by applying a low-polishing substrate having a low manufacturing cost, so that the supply of the substrate becomes smooth and the manufacturing cost of the liquid crystal display device can be reduced.

On the other hand, the liquid crystal display device is divided into a vertical electric field system, which is a liquid crystal driving system by an electric field which is applied up and down, and a horizontal electric field system, which is a liquid crystal driving system by a horizontal electric field.

Although the transverse electric field system in which the common electrode is formed on the array substrate has been described above, the method of planarizing the substrate according to the present invention can also be applied to the vertical electric field system in which the common electrode is formed on the color filter substrate.

In this case, the color filter substrate coated with the overcoat layer can be completed by flattening the color filter substrate according to the present invention in a vacuum chamber, curing it, and then ejecting the vacuum chamber to form a common electrode on the separated color filter substrate.

The embodiments of the present invention as described above are merely illustrative, and those skilled in the art can make modifications without departing from the gist of the present invention. Accordingly, the protection scope of the present invention includes modifications of the present invention within the scope of the appended claims and equivalents thereof.

140: Color filter substrate 145: Black matrix
146a: Red color filter 146b: Green color filter
147: Overcoat layer 200: Vacuum chamber
220: first substrate supporting part 230: second substrate supporting part
260: High abrasive glass substrate

Claims (8)

Forming a black matrix on the boundary of each pixel region on the first substrate having the first flatness;
Forming a color filter corresponding to each of the pixel regions so that an edge overlaps the edge of the black matrix;
Forming an organic insulating layer on the black matrix and the color filter;
A first substrate on which the organic insulating film is formed and a second substrate having a second flatness lower than the first flatness on an upper portion of the first substrate are disposed in a vacuum chamber so as to face each other with a predetermined gap therebetween Wow;
Making the interior of the vacuum chamber in a vacuum state and allowing the first substrate and the second substrate to adhere to each other by freely dropping the second substrate;
And curing the photo-curable resin.
The method according to claim 1,
The organic insulating film
A method of manufacturing a color filter substrate comprising a photocurable resin.
delete The method according to claim 1,
Further comprising the step of discharging the first and second bonded substrates from the vacuum chamber.
5. The method of claim 4,
Further comprising the step of separating the second substrate from the first and second substrates bonded together.
A first substrate having a first flatness and a second substrate having a second flatness lower than the first flatness are disposed in a vacuum chamber so as to face each other with a predetermined gap therebetween, Placing the vacuum chamber in a vacuum state;
Allowing the second substrate to fall freely so that the first substrate and the second substrate are bonded together;
Comprising the step of photocuring,
Wherein the first substrate has red, green, and blue color filters and a black matrix, and the overcoat layer is coated on top of the color filter and the black matrix.
6. The method of claim 5,
Further comprising forming a common electrode on the first substrate after separating the second substrate.
The method according to claim 1,
Wherein the second substrate has a flatness value of less than 0.88, and the first substrate has a flatness value of 0.88 or more.

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