KR20050047879A - Liquid crystal display and manufacturing method thereof - Google Patents

Abstract

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: forming a color filter of a plurality of color regions on a first substrate; Forming a thin film transistor on the second substrate; Forming an interlayer insulating film on the thin film transistor; Forming a recess in the interlayer insulating film corresponding to each boundary of a plurality of color regions in the color filter; Forming a pixel electrode on the interlayer insulating film; And forming a liquid crystal layer between the first substrate and the second substrate. Thereby, the display characteristic of a liquid crystal display device can be improved.

Description

Liquid crystal display and manufacturing method

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, by forming a recess in an interlayer insulating film of a thin film transistor substrate corresponding to a stepped portion formed by overlapping a color filter, thereby improving liquid crystal alignment distortion. The present invention relates to a liquid crystal display and a manufacturing method for preventing a phenomenon such as high aperture ratio, afterimage and disclination of a screen.

Liquid crystal display is an application of the electro-optical properties of the liquid crystal to the display device by changing the arrangement of the liquid crystal molecules at the time of power supply by injecting a liquid crystal, which is an intermediate phase of a liquid and a solid between two thin glass substrates.

1A and 1B are cross-sectional views of a conventional thin film transistor and a view showing contact hole formation on a conventional thin film transistor.

As shown in FIG. 1A, a thin film transistor 560 includes a source 590s through which current enters on the second substrate 510T, a drain 590d through which current flows out, and a current flow. Gate 570 is responsible for the shielding of the. A gate insulating film 575 is formed on the gate 570 electrode.

When a voltage is applied to the gate 570 electrode, a channel is formed to allow a current to flow in the channel portion 580, which is a semiconductor, and data passes through the channel to the drain electrode 590d.

As shown in FIG. 1B, an interlayer insulating film 600 is formed on the thin film transistor 560 to protect the thin film transistor 560. The contact hole 630 is formed by drilling a hole from the interlayer insulating film 560 to the drain 590d electrode under the interlayer insulating film 560.

The contact hole 630 connects the transparent conductive film 610 and the thin film transistor 560 formed on the interlayer insulating film 560. After forming the contact hole 630, a transparent conductive material is formed on the entire first substrate 510T, and a pattern of the transparent conductive film 610 is formed using a photomask technique. Here, the transparent conductive film 610 drives the liquid crystal cell 690 to be formed later by the voltage delivered to the drain 590d electrode to turn on and off the transmission of light to implement an image.

2 is a cross-sectional view of a conventional color filter substrate.

Color resins 520R, 520G, and 520B of RGB colors are coated on the first substrate 510C and exposed to form a color filter 530 pattern. In general, a black mattress is formed on the first substrate 510C to partition the color gamut of the color resins 520R, 520G, and 520B, and then the color resins 520R, 520G, and 520B are coated on the first substrate 510C. Then, it was exposed to form a color filter 530. An overcoat is formed on the color filter 530 to make the first substrate 510C flat and the counter electrode 550 is formed on the planarization film.

However, when the black matrix is used, there is a disadvantage that the opening ratio is lowered, and a process of forming a pattern of the black matrix is further required. If the planarization layer is omitted, an improved RGB profile of the color filter 530 and sheet resistance of the counter electrode 550 may be reduced. In addition, when the color filter 530 is formed without using the black matrix and the planarization layer, the material cost may be reduced.

Therefore, in recent years, there is an increasing demand for forming the high-aperture color filter 530 by overlapping the color resins 520R, 520G, and 520B. As shown in FIG. 2, color resins 520R, 520G, and 520B of RBG are coated on the first substrate 510 and exposed to form a color filter 530. At this time, in order to prevent misalignment and color division of the RGB color resins 520R, 520G and 520B, the boundary portions of the RBG color resins 520R, 520G and 520B are overlapped. In this process, the boundary of the overlapping color gamut causes a step.

3 is a view illustrating a liquid crystal layer formed by bonding a first substrate and a second substrate to a conventional substrate. The liquid crystal layer 700 is formed between the two substrates 510C and 510T by bonding the first substrate 510C and the second substrate 510T together. The liquid crystal of the liquid crystal layer 700 is driven by receiving an electric field by the transparent conductive film 610 formed in the thin film transistor 560.

Herein, liquid crystal refers to a material in the intermediate state between a liquid and a solid, which has both liquid properties such as dielectric properties and crystals (solids) such as long range order. Liquid crystal molecules have a unique rod-shaped structure, and thus have anisotropic properties in which physical properties such as refractive index, dielectric constant, conductivity, and viscosity are different from each other in a direction parallel to and perpendicular to the major axis of the molecule. In order to exhibit the properties, it becomes a very important physical property.

Optical anisotropy of liquid crystal means that the refractive index of light oscillating in the major axis direction of liquid crystal molecules exhibits birefringence due to different refractive index anisotropy. The refractive anisotropy of the liquid crystal serves to change the polarization state of the light passing through the liquid crystal or the vibration direction of the polarization.

The dielectric anisotropy of the liquid crystal refers to a property in which the dielectric constant in the direction perpendicular to the long axis of the liquid crystal molecule is different. As a result, the response of the liquid crystal is changed according to the intensity of the voltage applied to the liquid crystal layer 700, and thus the amount of light transmitted by the optical anisotropy is controlled. Liquid crystals whose dielectric constant in the major axis direction is shorter than the short axis are called P-type liquid crystals, and liquid crystals whose dielectric constant in the major axis direction is weaker than the minor axis direction are referred to as N-type liquid crystals.

The elastic modulus of the liquid crystal is a value obtained by quantifying a state in which the uniform molecular arrangement of the liquid crystal is changed by an external force, and represents the strength of the force that returns to its original position after reacting with a voltage.

Due to this property of the liquid crystal, the distance between the mutual electrodes 550 and 610 is affected. Since the arrangement of the liquid crystals is changed by the distance between the mutual electrodes 550 and 610, afterimages and shifts of the screen occur, which causes a decrease in display characteristics.

3, color resins 520R, 520G, and 520B overlap each other on the first substrate 510C, and overlapping color resins 520R, 520G, and 520B overlap the first substrate 510C. Due to the stepped portion 540, the electrode gap between the first substrate 510C and the second substrate 510T is not constant. As a result, distortion of the liquid crystal array occurs. As a result, problems such as afterimage and rotation occurred on the screen.

As such, the color filter 530 is formed by overlapping the conventional color resins 520R, 520G, and 520B so that the interval between the liquid crystal layer 700 formed between the first substrate 510C and the second substrate 510T is constant. In this case, the liquid crystal array may be distorted, and thus the display characteristics of the liquid crystal display may be degraded.

Accordingly, an object of the present invention is to form a liquid crystal layer 700 by bonding the color filter 530 formed on the first substrate 510C and the thin film transistor 560 formed on the second substrate 510T. The present invention provides a liquid crystal display device and a method of manufacturing the same, which have improved display characteristics by improving distortion of the liquid crystal array.

According to the present invention, there is provided a liquid crystal display device manufacturing method comprising the steps of: forming a color filter of a plurality of color regions on a first substrate; Forming a thin film transistor on the second substrate; Forming an interlayer insulating film on the thin film transistor; Forming a recess in the interlayer insulating film corresponding to each boundary of a plurality of color regions in the color filter; Forming a pixel electrode on the interlayer insulating film; And forming a liquid crystal layer between the first substrate and the second substrate.

The method may further include heat treating the interlayer insulating layer after forming the concave portion, and the formation angle of the interlayer insulating layer may be lowered through heat treatment to prevent lifting of the pixel electrode. Adjacent defects can be reduced by increasing the separation between the pixel electrode and the pixel electrode at the boundary portion.

In the forming of the recess in the interlayer insulating layer, it is preferable to further form a contact hole connecting the pixel electrode and the thin film transistor.

Forming an additional interlayer insulating film on the interlayer insulating film on which the concave portion and the contact hole are formed; And forming a via hole in the additional interlayer insulating film so that a plurality of steps are formed in the contact hole.

On the other hand, a liquid crystal display device comprising: a first substrate on which a color filter is formed; A second substrate on which a thin film transistor is formed; An interlayer insulating film formed on the second substrate; A recess formed on the interlayer insulating film; And a liquid crystal layer formed between the first substrate and the second substrate.

Hereinafter, a liquid crystal display for improving display characteristics by forming a recess in an interlayer insulating film formed on a thin film transistor used in the liquid crystal display as an example will be described.

Prior to the description, in various embodiments, components having the same configuration will be described in the representative embodiments using the same reference numerals.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

6 is a cross-sectional view showing a liquid crystal panel according to the present invention.

As shown in FIG. 6, the color filter 30 is applied onto the first substrate 10C by using materials such as color resins 20R, 20G, and 20B. Here, the color resins 20R, 20G, and 20B are resins containing dyes or pigments of three primary colors (R, G, and B). The color filter 30 serves to make the light passing through the liquid crystal layer 200 to be formed later have a color.

Here, in order to prevent the division of color of the color resins 20R, 20G, and 20B and misalignment when forming the color filter 30 pattern, a color is formed at the boundary of each color resin 20R, 20G, and 20B, as shown in FIG. The resins 20R, 20G, and 20B overlap each other. The step is formed at the boundary of the color gamut due to the overlapping color resins 20R, 20G, and 20B.

Here, the counter electrode 50 may be formed on the color filter 30 to form a voltage in the liquid crystal cell 190 with a transparent electrically conductive electrode material.

As shown in FIG. 6, the thin film transistor 60 is formed on the second substrate 10T so that the gate 70 electrode and the data 90 electrode are orthogonal to each other, and the signal of the gate 70 and the signal of the data are channels. The unit 80 reacts with the pixel electrode 110 to be formed later. The gate insulating layer 75 is formed on the gate electrode 70.

An interlayer insulating film 100 that protects the thin film transistor 60 is formed on the thin film transistor 60 formed as shown in FIG. 6. The interlayer insulating film 100 may be formed of a material such as SiNx or an organic film.

Since the thickness of the interlayer insulating film 100 affects the aperture ratio, cross talk, and transmittance of the liquid crystal display device, the type of the interlayer insulating film 100 and the thickness of the interlayer insulating film 100 are selected according to desired characteristics. It is desirable to.

The pixel electrode 110 is formed on the interlayer insulating film 100. The pixel electrode 110 is formed of a transparent and electrically conductive material and serves to apply a signal voltage applied through the thin film transistor 60 to the liquid crystal cell 190.

The liquid crystal layer 200 is formed between the first substrate 10C and the second substrate 10T. The liquid crystal layer 200 is driven by receiving an electric field by the pixel electrode 110 formed in the thin film transistor 60.

Here, the first substrate 10C and the second substrate 10T are bonded to each other, and the color resins 20R, 20G, and 20B overlap each other at the boundary of the color filter 30 on the first substrate 10T. A stepped portion 40 is formed at the boundary.

The liquid crystal of the liquid crystal layer 200 drives the liquid crystal cell 190 by an electric field. The driven liquid crystal is affected by the distance between the counter electrode 50 and the pixel electrode 110. When the electrode gap is not formed uniformly, the liquid crystal array is distorted, which causes deterioration of display characteristics.

Thus, the recess 120 is formed in the interlayer insulating film 100 to form a constant gap between the liquid crystal layer 200 formed between the first substrate 10C and the second substrate 10T. The recess 120 on the second substrate 10T is formed at a position corresponding to the step 40 of the first substrate 10C to prevent the liquid crystal cell 190 from being twisted.

The pixel electrode 110 is formed on the interlayer insulating film 100. The contact hole 130 is further formed to connect the pixel electrode 110 and the drain electrode 90d receiving the data signal.

The liquid crystal of the liquid crystal layer 200 formed between the first substrate 10C and the second substrate 10T is in a state in which liquid crystals, which are organic molecules having fluidity such as liquid, are regularly arranged like crystals. It serves to display the array using the property that is changed by the external electric field.

Since the distance between the liquid crystals is affected by the distance between the pixel electrode 110 of the first substrate 10C and the counter electrode 50 of the second substrate 10T, it is necessary to form a constant gap between the electrodes 50 and 110. desirable.

4A to 4D illustrate a process of forming a color filter on a first substrate.

The color filter 30 serves to make the light passing through the liquid crystal layer 200 to be formed later have a color. As shown in Figs. 4A to 4D, the first substrate is prepared, and a red resin 20R is coated and exposed in the color resins 20R, 20G, and 20B to form a pattern of the red color resin 20R. . Then, the green (G) color resin 20G is applied and exposed to form a pattern of the green color resin 20G. Blue 20B is formed in the same manner.

The color resins 20R, 20G, and 20B of the color filter 30 use colored pigments or dyes. In addition, the color resins 20R, 20G, and 20B use a negative reaction photoresist (PR) in which a lighted area is cured. The color resins 20R, 20G, and 20B of each color are formed by overlapping each other to prevent defects due to color division and misalignment of the color resins 20R, 20G, and 20B at the boundary of the color.

5A to 5F illustrate a process of forming a thin film transistor on a second substrate according to the present invention.

As shown in FIG. 5A, the gate electrode 70, the data electrode 90, and the channel unit 80 are formed on the second substrate 10T. The gate electrode 70 is formed by etching and etching using chromium, an aluminum alloy, or the like, and forms the gate insulating layer 75 on the entire second substrate 10T by PECVD on the gate electrode 70. The channel portion 80 is formed on the gate insulating layer 75. The channel portion 80 may be formed of a semiconductor material such as amorphous silicon (a-Si) or polysilicon (poly-Si) by PECVD. The data electrode 90 forms a pattern by depositing and etching the material of the data electrode 90 on the channel portion 80. As the data electrode 90 material, chromium, molybdenum, aluminum alloy, or the like may be used.

As shown in FIG. 5B, an interlayer insulating layer 100 is formed on the thin film transistor 60 to protect the thin film transistor 60. The interlayer insulating film 100 may be formed of SiNx, an organic film, or the like. In the present invention, an organic film is described as an embodiment.

As shown in FIG. 5C, the interlayer insulating film 100 formed of the organic film exposes the organic film having the stepped portion 40 at a position corresponding to the stepped portion 40 formed on the first substrate 10C. Thus, when the first substrate 10C and the second substrate 10T are bonded together, the concave portion 120 is formed to uniformly form a gap between the two substrates 10C and 10T.

In this case, when the recess 120 is exposed and formed, a contact hole 130 for connecting the data electrode 90 and the pixel electrode 110 (see FIG. 6) may be further formed.

As shown in FIG. 5D, an additional interlayer insulating film 100a may be further applied. A stepped profile may be formed in the contact hole 130 by applying an additional interlayer insulating film 100a and exposing the applied additional interlayer insulating film 100a. When exposing the additional interlayer insulating film 100a, the via amount 135 may be formed by adjusting the exposure amount.

As shown in FIG. 5E, the stepped profile is generated because the inclination of the interlayer insulating layers 100 and 100a formed after exposure is abrupt and the material of the pixel electrode 110 to be formed on the contact hole 130 does not come into contact with the organic layer. To prevent the lifting phenomenon. Here, the organic film may be applied several times and exposed to form a multi-stepped profile.

As illustrated in FIG. 5E, an angle formed in the contact hole 130 may be suddenly shorted to cause a short circuit of the material of the pixel electrode 110. Here, the steep slope formed of the contact hole 130 and the recess 120 may be lowered by heat treating the organic layer. Of course, the inclination may be lowered through heat treatment to prevent the pixel electrode 110 from being short-circuited.

As illustrated in FIG. 5F, the pixel electrode 110 is formed by depositing and etching a transparent conductive material on the interlayer insulating layer 100, but the pixel electrode 110 should not be connected to the recess 120. The recess 120 may improve adjacent defects between pixels by increasing a separation 150 between the pixel electrode 110 and the pixel electrode 110.

6, the first substrate 10C and the second substrate 10T are bonded to each other to form the liquid crystal layer 200 between the two substrates. On the second substrate 10T formed according to the present invention, a recess 120 is formed to form a constant gap between the liquid crystal layers 200, thereby preventing the liquid crystal from being distorted. Accordingly, problems such as afterimages and rotations occurring on the screen of the liquid crystal display can be solved.

As described above, the liquid crystal display according to the present invention forms a concave portion 120 that prevents the liquid crystal array from being distorted, thereby solving problems such as repositioning and afterimage of the liquid crystal array, and widening the interval 150 between the pixel electrodes. Adjacent defects between the electrode 110 and the pixel electrode 110 can be solved. In addition, by applying and exposing an additional interlayer insulating film 100a on the interlayer insulating film 100, the contact hole 130 is formed in a stepped profile to generate the data 90 electrode and the pixel electrode 110 generated in the contact hole 130. Poor contact between the liver can be improved. In addition, when the recess 120 and the contact hole 130 are formed in two steps in the stepped profile in the process, the process of applying and exposing can be formed without increasing the number of times of using the mask as compared with the conventional process. This is easy and the quality of the liquid crystal display device can be improved.

As described above, the liquid crystal display according to the present invention forms a concave portion 120 that prevents the liquid crystal array from being distorted, thereby solving problems such as repositioning and afterimage of the liquid crystal array, and widening the interval 150 between the pixel electrodes. Adjacent defects between the electrode 110 and the pixel electrode 110 can be solved. In addition, by applying and exposing an additional interlayer insulating film 100a on the interlayer insulating film 100, the contact hole 130 is formed in a stepped profile to generate the data 90 electrode and the pixel electrode 110 generated in the contact hole 130. Poor contact between the liver can be improved. In addition, when the recess 120 and the contact hole 130 are formed in two steps in the stepped profile in the process, the process of applying and exposing can be formed without increasing the number of times of using the mask as compared with the conventional process. This is easy and the quality of the liquid crystal display device can be improved.

1A is a cross-sectional view of a conventional thin film transistor.

1B is a view illustrating a contact hole formation on a conventional thin film transistor;

2 is a cross-sectional view of a conventional color filter substrate,

3 is a view showing a liquid crystal layer formed by bonding a conventional first substrate and a second substrate;

4A to 4D are views illustrating a process of forming a color filter on a first substrate according to the present invention;

5A to 5F illustrate a process of forming a thin film transistor on a second substrate according to the present invention;

6 is a cross-sectional view of a liquid crystal panel according to the present invention.

* Explanation of symbols for the main parts of the drawings

 10 substrate 15 mask

 20: color resin 30: color filter

 40: step 50: counter electrode

 60: thin film transistor 70: gate

 75 gate insulating film 80 channel portion

 90 data electrode 100 interlayer insulating film

105: additional interlayer insulating film 110: pixel electrode

120: recess 130: contact hole

190: liquid crystal cell 200: liquid crystal layer

Claims (5)

In the liquid crystal display manufacturing method, Forming a color filter of a plurality of color regions on the first substrate; Forming a thin film transistor on the second substrate; Forming an interlayer insulating film on the thin film transistor; Forming a recess in the interlayer insulating film corresponding to each boundary of a plurality of color regions in the color filter; Forming a pixel electrode on the interlayer insulating film; Forming a liquid crystal layer between the first substrate and the second substrate. The method of claim 1, And heat-treating the interlayer insulating film after the forming of the recesses. The method of claim 1, And forming a recess in the interlayer insulating layer, further forming a contact hole connecting the pixel electrode and the thin film transistor. The method of claim 2, Forming an additional interlayer insulating film on the interlayer insulating film on which the concave portion and the contact hole are formed; Forming a via hole in the additional interlayer insulating film such that a plurality of steps are formed in the contact hole. In the liquid crystal display device, A first substrate on which a color filter is formed; A second substrate on which a thin film transistor is formed; An interlayer insulating film formed on the second substrate; A recess formed on the interlayer insulating film; And a liquid crystal layer formed between the first substrate and the second substrate.