KR100611216B1 - Flat Panel Display with Black Matrix and Fabrication Method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device having a black matrix capable of simplifying the process by using the transmittance characteristic of the transparent conductive film and reducing the surface step, and a manufacturing method thereof.

According to an aspect of the present invention, there is provided a method of manufacturing a flat panel display device, comprising: providing an insulating substrate having a first region where a pixel electrode is to be formed and a second region where a thin film transistor is to be formed; Forming a pixel electrode in a first region using a halftone mask and forming a black matrix in a second region; Forming an insulating film on the front surface of the substrate; Forming the thin film transistor connected to the pixel electrode in a portion of the insulating layer of the second region corresponding to the black matrix; Forming a planarization film on the entire surface of the substrate; Etching the planarization layer to form an opening exposing a portion of the pixel electrode.

Description

Flat panel display with black matrix and manufacturing method thereof {Flat Panel Display with Black Matrix and Fabrication Method}

1 is a cross-sectional structure diagram of a conventional organic light emitting display device;

2A to 2G are cross-sectional structural views of an organic light emitting display device according to an embodiment of the present invention;

3A to 3D are cross-sectional structural views of an organic light emitting display device according to another embodiment of the present invention;

4 is a view showing the transmittance characteristics of the transparent conductive film according to the ion implantation of impurities,

* Description of the symbols for the main parts of the drawings *

100, 300: insulation substrate 120, 310: transparent conductive film

125, 390: pixel electrodes 130, 320: photosensitive film

140 and 320 buffer layers 150 and 330 semiconductor layers

171, 351: Gate 151 152, 351 352: Source / drain region

160, 340: gate insulating film 175, 373: capacitor lower electrode

180, 360: interlayer insulating film 181-183: contact hole

250: halftone mask 191 192, 371 372: source / drain electrodes

193 and 373: capacitor upper electrode 200: planarization film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device, and more particularly, to an organic light emitting display device having a black matrix using a transmittance characteristic of a transparent conductive film, and a manufacturing method thereof.

1 shows a cross-sectional structure of a conventional organic light emitting display device. Referring to FIG. 1, a method of manufacturing a conventional organic light emitting display device is as follows.

First, a buffer layer 11 is formed on a transparent insulating substrate 10 made of glass, synthetic resin, or the like, a polysilicon film is coated on the buffer layer 11, and a mask for forming a semiconductor layer (not shown in the drawing) is applied. The polysilicon film is patterned to form a semiconductor layer 13.

A gate insulating layer 15 is formed on the buffer layer 11 including the semiconductor layer 13, and a gate metal is deposited on the gate insulating layer 15. The gate metal is patterned by using a gate forming mask (not shown in the drawing) to form the gate electrode 16 in a portion of the gate insulating layer 15 corresponding to the semiconductor layer 13. When forming the gate electrode 16, the lower electrode 17 of the capacitor 52 is formed at the same time.

Source / drain regions 13-1 and 13-2 are implanted into the semiconductor layer 13 by implanting impurities of a predetermined conductivity type, for example, N-type or P-type impurities. At this time, the portion 13-3 between the source / drain regions 13-1 and 13-2 in the semiconductor layer 13 serves as a channel layer.

An interlayer insulating film 19 is formed on the gate insulating film 15 including the gate electrode 16 and the lower electrode 17 of the capacitor. The interlayer insulating layer 19 and the gate insulating layer 15 are etched to form contact holes 20-1 and 20-2 exposing the source / drain regions 13-1 and 13-2. .

Subsequently, a source / drain metal is deposited on the interlayer insulating film 19, and patterned using a source / drain electrode forming mask (not shown) to form the source / drain regions 13-1 and ( Source / drain electrodes 22-1 and 22-2 in contact with 13-2, and at the same time one of the source / drain electrodes 22-1 and 22-2, for example, a source The upper electrode 22-3 of the capacitor 52 connected to the electrode 22-1 is formed.

As a result, the thin film transistor 51 and the capacitor 52 of the organic light emitting display device are formed. At this time, the portion of the interlayer insulating film 19 formed between the upper and lower electrodes 17 and 22-3 of the capacitor 52 serves as a dielectric of the capacitor.

After the source / drain electrodes 22-1, 22-2 and the upper electrode 22-3 are formed, a passivation film 25 is formed on the interlayer insulating film 19, and a via hole forming mask (Fig. (Not shown) to etch the passivation film 25 to expose one of the source / drain electrodes 22-1 and 22-2, for example, a drain electrode 22-2. (26) is formed.

Thereafter, a transparent conductive film, for example, ITO, is deposited on the passivation film 25, and then patterned ITO using a pixel electrode forming mask (not shown) to form the pixel electrode 27 serving as an anode electrode. Form. In this case, the pixel electrode 27 is electrically connected to the drain electrode 22-2 through the via hole 26.

When the anode electrode 27 is formed in this manner, the planarization film 28 is formed on the passivation film 25 including the anode electrode 27 and planarized using an opening forming mask (not shown). A portion of the film 28 corresponding to the anode electrode is etched to form an opening 28-1 to expose the anode electrode 27.

Thereafter, an organic material is deposited on the anode electrode 27 of the opening 28-1 to form an organic EL layer 29 which emits red, green, and blue light by current. The cathode electrode 30 is formed by depositing a cathode metal on the entire surface of the substrate to form the organic EL element 53.

A flat panel display device, such as an AMOLED (Active Matrix Organic Light Emitting Device), consists of a switching device and various wirings for applying power to the switching device, and external light is reflected by the wiring metal material so that contrast is greatly increased. Degrades. That is, as indicated by arrows in FIG. 1, external light is reflected by the metal material constituting the lower electrode of the capacitor, the electrode material constituting the source / drain electrode and the upper electrode of the capacitor, and the electrode material constituting the cathode.

Conventionally, an expensive polarizing plate is attached to the front surface to prevent a decrease in contrast due to reflection of external light, but not only causes an increase in manufacturing cost due to the use of an expensive polarizing plate, but also the polarizing plate itself blocks light emitted from the organic electroluminescent layer. There is a problem that the luminance is lowered by lowering the transmittance.

Meanwhile, there is a method of separately forming a black matrix made of Cr / CrOx or an organic film in a TFT region excluding a pixel region, that is, a region in which a TFT and a capacitor are formed. In this method, a separate mask is formed to form a black matrix. Not only is there a problem in that a process is required but also a step difference between the TFT region where the black matrix is formed and the pixel region is increased, causing a short circuit between the metal wiring, that is, the source / drain electrode and the gate electrode.

Accordingly, an object of the present invention is to provide a method of manufacturing a flat panel display device having a black matrix, which simplifies the process.

Another object of the present invention is to provide a flat panel display device capable of forming a black matrix and a pixel electrode without a separate mask process by using the transmittance deformation characteristic of the transparent conductive film, and a manufacturing method thereof.

Another object of the present invention is to provide a flat panel display device and a method of manufacturing the same, which can prevent generation of steps between a pixel region and a TFT region due to the formation of a black matrix.

In order to achieve the above object, the present invention provides an insulating substrate having a first region in which a pixel electrode is to be formed and a second region in which a thin film transistor is to be formed; Forming a pixel electrode in a first region using a halftone mask and forming a black matrix in a second region; Forming an insulating film on the front surface of the substrate; Forming the thin film transistor connected to the pixel electrode in a portion of the insulating layer of the second region corresponding to the black matrix; Forming a planarization film on the entire surface of the substrate; And forming an opening through which the flattening layer is etched to expose a portion of the pixel electrode.

The method of forming the pixel electrode and the black matrix may include forming a transparent conductive film on the entire surface of the substrate; Coating a photosensitive film on the transparent conductive film; Patterning the photoresist with a halftone mask to form a first photoresist pattern in the first region and a second photoresist pattern that is thinner than the first photoresist pattern in the second region; Etching the transparent conductive film using the first and second photoresist pattern to form a second pattern in the first pattern and the second region in the first region; Implanting impurities using the first photoresist pattern as a mask to modify the transmittance of the second pattern to form a black matrix; And removing the remaining first photoresist pattern to form a first pattern under the pixel electrode.

The present invention also provides an insulating substrate having a first region where a pixel electrode is to be formed and a second region where a thin film transistor is to be formed; Forming a transparent conductive film on the entire surface of the substrate; Forming a photoresist film to expose a portion of the transparent conductive film corresponding to the second region; Forming a black matrix by injecting impurities into the exposed transparent conductive film using the photosensitive film as a mask to modify the transmittance; Forming a first insulating film on the entire surface of the substrate; Forming a thin film transistor on a first insulating film corresponding to the black matrix; Forming a second insulating film on the entire surface of the substrate; Forming a pixel electrode connected to the thin film transistor in a portion of a second insulating film corresponding to the first region; Forming a third insulating film on the front surface of the substrate; And forming an opening through which the third insulating layer is etched to expose a part of the pixel electrode.

The present invention also provides an insulating substrate including a first region in which pixel electrodes are formed and a second region in which thin film transistors are formed; A flat panel display comprising a transparent conductive film formed on the insulating substrate and having a portion serving as a pixel electrode in a first region and a portion serving as a black matrix in a second region.

The portion formed in the second region of the transparent conductive film is a portion whose permeability is modified by impurity ion implantation, and the impurity into the transparent conductive film is ion-implanted at least once with a high energy source of 40 to 100 keV.

The portion of the transparent conductive film serving as the pixel electrode and the portion serving as the black matrix may be separated from each other, or the portion formed on the front surface of the substrate and serving as the pixel electrode may be connected to each other.

Hereinafter, a method of manufacturing a flat panel display device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

2A through 2G are cross-sectional views illustrating a method of manufacturing an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2A, a transparent insulating substrate 100 having a TFT region 101 on which a TFT and a capacitor are to be formed and a pixel region 102 on which an organic light emitting element including a pixel electrode is to be formed is provided. A transparent conductive film 120 is formed on the insulating substrate 100, and a photosensitive film 130 is coated on the transparent conductive film 120. In this case, one of photoresist, BCB, PI, and acryl is used as the photosensitive film 130.

Next, the photosensitive film 130 is patterned using a halftone mask 250. In this case, the halftone mask 250 includes a semi-transmissive region 251 for transmitting a portion of light corresponding to a portion where the black matrix of the TFT region 101 is to be formed, and a pixel electrode of the pixel region 102. And a blocking area 252 for completely blocking light, corresponding to the portion to be formed. The remaining portions except for the transflective region 251 and the blocking region 252 may be transmissive regions that completely transmit light.

When the photoresist layer 130 is patterned using the halftone mask 250, the patterns 131 and 132 of the photoresist layer 130 are obtained as shown in FIG. 2B. The pixel region 102 of the photoresist layer 130 is obtained. The pattern 132 formed on the photoresist film is maintained as it is, and the pattern 131 formed on the TFT region 101 has a thickness relatively thinner than the pattern 132 on the pixel region 102.

Subsequently, when the transparent conductive film 120 is patterned using the photosensitive film 130, only the transparent conductive film remains in the TFT region 101 as shown in FIG. 2C, and the transparent region is transparent in the pixel region 102. The pattern 132 of the photosensitive film is present on the conductive film.

Next, when an impurity is implanted at a high energy of 40 to 100 keV, in the pixel region 102, the pattern 132 of the photoresist film acts as a mask for ion implantation so that no impurity is injected into the transparent conductive film below the TFT region 101. Impurities are implanted only into the transparent conductive film of?). At this time, the impurity implantation process injects impurities such as H, P, B, As, Ar with high energy using an ion implanter. ITO, IZO, ZnO and the like are used as the transparent conductive film.

Referring to FIG. 4, a transparent conductive film is a material having a property of changing its transmittance when an impurity is injected. A transparent conductive film having ion implanted therein is in contrast to a polarizing plate (λ / 4) that is generally used has a transmittance of 50%. Silver has a transmittance lower than that of the polarizing plate.

That is, in the case of ion implantation of boron using B2H6 gas, it can be seen that the ion implantation with a dose amount of 1.5x10 ¹⁶ ions / cm 2 has a transmittance of 30%. Therefore, it can be seen that when a predetermined impurity is implanted into the transparent conductive film with a high energy source as in the present invention, its permeability is modified to serve as a black matrix.

In the above, the ion is implanted into the transparent conductive film by a single ion implantation process, but when the ion implantation is performed two or more times at different acceleration voltages, its permeability is further lowered. In the case where ion implantation is performed a plurality of times, the total dose of impurities to be implanted is the same.

Therefore, the transparent conductive film 125 which is not doped with impurities serves as a pixel electrode, and the transparent conductive film 121 whose impurity is ion implanted to reduce its transmittance serves as a black matrix. In this case, the pattern 121 of the black matrix transparent conductive film may be formed over the entire area except the pixel area. Therefore, in one embodiment of the present invention, the pixel electrode and the black matrix can be simultaneously formed by using one halftone mask by using the transmittance deformation characteristic of the transparent conductive film caused by impurity ion implantation.

As shown in FIG. 2D, a buffer layer 140 is formed on a substrate 100 having a pixel electrode 125 and a black matrix 121, and a poly layer is formed on the buffer layer 140 of the TFT region 101. A semiconductor layer 150 made of a silicon film is formed. The gate insulating layer 160 is formed on the buffer layer 140 including the semiconductor layer 150.

As shown in FIG. 2E, the gate 171 is formed on the gate insulating layer 160 on the semiconductor layer 150, and the lower electrode 175 of the capacitor is formed. Source / drain regions 151 and 152 are formed by ion implanting a predetermined conductivity type, for example, n-type or p-type impurities, into the semiconductor layer 150 using the gate 171 as a mask. In this case, the portion 153 between the source / drain regions 151 and 152 of the semiconductor layer 150 serves as a channel region.

As shown in FIG. 2F, an interlayer insulating layer 180 is formed on the gate insulating layer 160 including the gate 171 and the capacitor lower electrode 175, and the source / drain regions 151 and 152 and the pixel electrode are formed. First to third contact holes 181 to 183 are formed to expose 125, respectively. A source / drain electrode material is deposited on the interlayer insulating layer 180 including the contact holes 181 to 183 and then patterned.

Accordingly, the source electrode 191 contacts the source region 151 through the first contact hole 181, and the drain region 152 and the third contact hole 183 through the second contact hole 182. ) To form a drain electrode 192 that is in contact with the pixel electrode. At the same time, the capacitor upper electrode 193 is formed to be connected to the source electrode 191 so as to overlap with the capacitor lower electrode 175.

According to one embodiment of the present invention as described above, since the pixel electrode 125 is directly formed on the substrate and connected to the drain electrode 192 through a third contact hole 183 formed in a subsequent process, FIG. 1 Unlike the conventional device shown in FIG. 5, not only the process of forming a protective film between the source / drain electrode and the pixel electrode is excluded, but the process of forming a contact hole for forming the source / drain electrode and the pixel electrode is excluded, thereby eliminating the mask process. It is effective.

Referring to FIG. 2G, an opening 210 for exposing a portion of the pixel electrode 125 is formed after depositing the planarization film 200 on the entire surface of the substrate. Although not shown in the drawing, when the organic light emitting layer including the opening 210 is formed and a cathode is formed thereon, an organic light emitting display device according to an exemplary embodiment of the present invention is obtained.

According to one embodiment of the present invention as described above, while forming a black matrix, six mask processes, that is, a process for forming a pixel electrode and a black matrix, a semiconductor layer forming process, a gate forming process, a contact hole forming process, Since six mask processes of a source / drain electrode forming process and an opening forming process are required, the process can be simplified. In addition, the pixel electrode is formed on the substrate to prevent the decrease in luminance due to the conventional light passing through the multilayer insulating film, and to prevent the degradation of the contrast by forming the black matrix in all regions except the pixel portion.

In addition, in the exemplary embodiment of the present invention, the transparent conductive film is patterned using a halftone mask. However, when the halftone mask is formed so that the entire surface except the portion corresponding to the EL region is a blocking region, the EL region is subjected to the subsequent photoresist patterning process. Only the photoresist film is present and the photoresist film remains intact in the remaining areas. Therefore, a portion of the transparent conductive film whose transmittance is deformed is present in the pixel region as a black matrix, and a portion of which the transmittance is not deformed is present on the front surface of the substrate as the pixel electrode.

3A to 3D illustrate a cross-sectional structure for explaining a method of manufacturing an organic light emitting display device according to another embodiment of the present invention.

Referring to FIG. 3A, a transparent insulating substrate 300 having a TFT region 301 on which a TFT and a capacitor are to be formed and a pixel region 302 on which an organic light emitting device including a pixel electrode is to be formed are provided. The transparent conductive film 310 is deposited on the insulating substrate 300.

Referring to FIG. 3B, the photosensitive film 320 is coated on the transparent conductive film 310 and then patterned to be left only in the pixel region 302. By using the photosensitive film 320 as a mask, impurities are implanted into the transparent conductive film of the TFT region 301 with high energy. As a result, the portion 311 into which the impurity is injected is modified to transmit the black matrix, and the portion 315 of the lower portion of the photoresist layer 320 is not modified to transmit light, thereby emitting light emitted from the organic EL layer formed in a subsequent process. Is transmitted to the substrate.

In this case, the ion implantation process of impurities for modifying the permeability characteristics of the transparent conductive film according to the second embodiment is performed in the same manner as the ion implantation process of impurities for modifying the permeability characteristics of the transparent conductive film according to the first embodiment.

The photoresist film is one of photoresist, BCB, PI, or acrylic, and the impurity implantation process injects impurities such as H, P, B, As, Ar with high energy using an ion implanter. ITO, IZO, ZnO and the like are used as the transparent conductive film.

After removing the photoresist layer 320 as shown in FIG. 3C, as shown in FIG. 3D, a buffer layer 320 is formed on the entire surface of the substrate, and polysilicon is formed on the buffer layer 320 on the TFT region 301. A semiconductor layer 330 is formed of a film. The gate insulating layer 340 is deposited on the buffer layer 320 including the semiconductor layer 330, and the gate electrode 351 is formed on the gate insulating layer 340 on the semiconductor layer 330. The capacitor lower electrode 355 spaced apart from the electrode 351 is formed. Source / drain regions 351 and 352 are formed by ion implanting impurities of a predetermined conductivity type, for example, n-type or p-type, into the substrate using the gate electrode 351 as a mask.

After the interlayer insulating film 360 is deposited on the gate insulating film 340 including the gate electrode 351 and the capacitor lower electrode 355, the gate insulating film 340 and the interlayer insulating film 360 are etched to form the source / Contact holes 361 and 362 exposing the drain regions 351 and 352 are formed.

The source / drain electrode material is deposited on the interlayer insulating layer 360 including the contact holes 361 and 362 and then patterned to form the source / drain regions 351 through the contact holes 361 and 362. And source / drain electrodes 371 and 372 in contact with 352, and connected to one of the source / drain electrodes 371 and 372, for example, source electrode 371. The capacitor upper electrode 373 is formed to overlap the capacitor lower electrode 355.

Subsequently, a passivation layer 380 is deposited on the interlayer insulating layer 360 including the source / drain electrodes 371 and 372, and then one of the source / drain electrodes, for example, the drain electrode 372 is deposited. The via hole 381 which exposes is formed. A transparent conductive film is deposited on the passivation layer 380 including the via hole 381 and then patterned to form a pixel electrode 390.

Next, a planarization film 400 is formed on the passivation layer 380 including the pixel electrode 390, and an opening 401 exposing a portion of the pixel electrode 390 is formed. An organic EL layer 410 and a cathode 420 are formed on the opening 401 to manufacture the organic light emitting display device of the present invention.

According to another embodiment of the present invention as described above, the black matrix is formed and then the buffer layer is formed, but the black matrix may be formed after the buffer layer is formed. In addition, by forming the black matrix on the entire surface except the pixel region without patterning the transparent conductive film for forming the black matrix, there is an advantage that the generation of the step can be prevented.

According to the present invention as described above, by selectively implanting impurities into the transparent conductive film to modify its transmittance, the pixel electrode and the black matrix can be simultaneously formed in one mask process, so that one mask process can be omitted. In addition, the via hole process for forming the pixel electrode and the source / drain electrodes may be omitted, and thus, one mask process may be omitted. Therefore, there is an advantage that can simplify the process and improve the yield.                     

In addition, there is an advantage that the luminance can be improved by improving the transmittance by preventing reflection by external light without using an expensive polarizing plate. In addition, there is an advantage that a short circuit between wirings can be generated by preventing the generation of a step between the pixel region and the TFT region due to the formation of the black matrix.

Claims (9)

Providing an insulating substrate having a first region where a pixel electrode is to be formed and a second region where a thin film transistor is to be formed; Forming a pixel electrode in a first region using a halftone mask and forming a black matrix in a second region; Forming an insulating film on the front surface of the substrate; Forming the thin film transistor connected to the pixel electrode in a portion of the insulating layer of the second region corresponding to the black matrix; Forming a planarization film on the entire surface of the substrate; And forming an opening to expose a portion of the pixel electrode by etching the planarization layer. The method of claim 1, wherein the pixel electrode and the black matrix are formed. Forming a transparent conductive film on the entire surface of the substrate; Coating a photosensitive film on the transparent conductive film; Patterning the photoresist with a halftone mask to form a first photoresist pattern in the first region and a second photoresist pattern that is thinner than the first photoresist pattern in the second region; Etching the transparent conductive film using the first and second photoresist pattern to form a second pattern in the first pattern and the second region in the first region; Implanting impurities using the first photoresist pattern as a mask to modify the transmittance of the second pattern to form a black matrix; And removing the remaining first photoresist pattern to form a first pattern thereunder as a pixel electrode. The method of claim 2, wherein the impurity implantation is performed at least once with a high energy source of 40 to 100 keV. Providing an insulating substrate having a first region where a pixel electrode is to be formed and a second region where a thin film transistor is to be formed; Forming a transparent conductive film on the entire surface of the substrate; Forming a photoresist film to expose a portion of the transparent conductive film corresponding to the second region; Forming a black matrix by injecting impurities into the exposed transparent conductive film using the photosensitive film as a mask to modify the transmittance; Forming a first insulating film on the entire surface of the substrate; Forming a thin film transistor on a first insulating film corresponding to the black matrix; Forming a second insulating film on the entire surface of the substrate; Forming a pixel electrode connected to the thin film transistor in a portion of a second insulating film corresponding to the first region; Forming a third insulating film on the front surface of the substrate; And forming an opening through which the third insulating layer is etched to expose a portion of the pixel electrode. The method of claim 4, wherein the impurity is injected at least once into a high energy source of 40 to 100 keV. An insulating substrate having a first region in which pixel electrodes are formed and a second region in which thin film transistors are formed; And a transparent conductive film formed on the insulating substrate and having a portion serving as a pixel electrode in a first region and a portion serving as a black matrix in a second region. The flat panel display of claim 6, wherein a portion of the transparent conductive film formed in the second region is modified by impurity ion implantation. The flat panel display of claim 6, wherein a portion of the transparent conductive layer serving as a pixel electrode and a portion serving as a black matrix are separated from each other. The flat panel display of claim 6, wherein the transparent conductive film is formed on the front surface of the substrate, and a portion serving as a pixel electrode and a portion serving as a black matrix are connected to each other.

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