KR100704377B1 - Flat panel display and manufacturing method - Google Patents

Abstract

The present invention relates to a flat panel display device having an insulating film composed of two oxide films having different refractive indices, and a manufacturing method thereof. The flat panel display includes a plurality of insulating films formed on a substrate; A thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode stacked between one of the plurality of insulating layers; A planarization film formed on the source / drain electrodes; And a light emitting device having a first electrode, a light emitting layer, and a second electrode, and formed on the planarization film, wherein at least one of the plurality of insulating films is formed of two or more oxide films having different refractive indices. Thus, the insulating film composed of oxide films having different refractive indices can prevent reflection of light flowing from the outside and prevent the contrast from being lowered.

Oxide, insulating film, refractive index

Description

A flat panel display device and the manufacturing method

1 is a side cross-sectional view of a flat panel display device according to the present invention.

FIG. 2 is an enlarged view of a region of FIG. 1.

3A is a graph of refractive index change according to one component change when two oxide films having different refractive indices are used.

3B is a graph of refractive index change according to a change in titanium content when a titanium oxide film and an aluminum oxide film are mixed.

4 is a graph showing a change in refractive index according to the number of cycles.

5A and 5B are graphs illustrating a change in refractive index according to the thickness of a thin film.

6 is a graph showing the reflection characteristics of the insulating film deposited by varying the number of cycles.

* Explanation of symbols on main parts of drawings *

100: flat panel display 101: substrate

102: insulating film or metal thin film 103: semiconductor layer

104, 106 insulating film 105: gate electrode

107: source / drain electrode 108: planarization film

109: protective film 110: first electrode

111: light emitting layer 112: second electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display and a method for manufacturing the same, and more particularly, to a flat panel display including a transparent insulating film formed of two or more oxide films having different refractive indices and a method of manufacturing the same.

A flat panel display such as an active matrix light emitting display (AMOLED) includes at least one light emitting element, a switching element and a driving element, and a plurality of wirings for applying power to the switching element and the driving element. The wiring is formed of a metal material. In general, since the metal material is reflective, light from the outside is reflected by the wiring metal material, thereby reducing the contrast of the flat panel display. Accordingly, in order to prevent contrast degradation in the manufacturing process of the conventional flat panel display device, a method of attaching a polarizing plate to one region of the flat panel display device is used. There is a problem in that a part of the light is blocked to decrease the transmittance and reduce the luminance.

In order to solve this problem, Korean Patent Publication No. 10-0491143 discloses a black matrix by mixing a metal (for example, Cr and Mo) and an oxide film (for example, CrOx and MoOx) to form a black matrix. A method of use has been proposed. In the case of using a black matrix, by forming a metal film having a high refractive index by mixing the oxide film having a low refractive index, when light is incident on the oxide film having a low refractive index from the outside, the decrease in contrast can be prevented. However, when the black matrix is used in the bottom emission type flat panel display, the light emitted from the light emitting device is absorbed by the black matrix. In addition, the inorganic electroluminescent device disclosed in US Pat. No. 5,504,389 has a light absorbing layer between the insulating film and the electrode to absorb light. In this case, the light absorbing layer having the refractive index is required to be installed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a flat panel display device having a specific refractive index by changing the composition of the insulating film or a transparent insulating film having a refractive index gradient according to the thickness of the insulating film and a method of manufacturing the same. To provide.

Another object of the present invention is to provide a flat panel display device having a transparent insulating film having a desired refractive index uniformly in a large area at low temperature, and a manufacturing method thereof.

It is still another object of the present invention to provide a flat panel display device having a transparent insulating film capable of serving as a protective film and an antireflection film, and a manufacturing method thereof.

According to an aspect of the present invention, a flat panel display device includes: a plurality of insulating films formed on a substrate; A thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode stacked between one of the plurality of insulating layers; A planarization film formed on the source / drain electrodes; And a light emitting device having a first electrode, a light emitting layer, and a second electrode, and formed on the planarization film, wherein at least one of the plurality of insulating films is formed of two or more oxide films having different refractive indices.

Preferably, the oxide film is selected from a silicon oxide film (SiO 2), a titanium oxide film (TiO 2), an aluminum oxide film (Al 2 O 3), a zirconium oxide film (ZrO 2) and a tantalum oxide film (Ta 2 O 5). The selected oxide films are deposited by plasma atomic vapor deposition.

On the other hand, according to another aspect of the invention, the manufacturing method of the flat panel display device comprises the steps of forming a semiconductor layer, a gate electrode and a source / drain electrode on the substrate; Forming an insulating film on the substrate, the semiconductor layer, the gate electrode, and the source / drain electrode, respectively, wherein at least one of the insulating films is formed of two or more oxide films having different refractive indices; And forming a light emitting device including a first electrode, a light emitting layer, and a second electrode on an insulating layer formed on the source / drain electrodes.

Preferably, the step of forming the insulating film to an oxide film is deposited by plasma atomic vapor deposition. In the case of using the plasma atomic vapor deposition method, the content of the oxide film constituting the insulating film is controlled by the number of cycles. When the insulating film is formed, a silicon oxide film (SiO ₂ ), a titanium oxide film (TiO ₂ ), an aluminum oxide film (Al ₂ O ₃ ), a zirconium oxide film (ZrO ₂ ) and a tantalum oxide film (Ta ₂ O ₅ ) are formed. The refractive index is formed differently by controlling the amount of oxide films constituting the insulating film. The insulating film is composed of a single layer or multiple layers.

Hereinafter, a flat panel display device having a transparent insulating film and a method of manufacturing the same will be described in detail with reference to the drawings.

1 is a side cross-sectional view of a flat panel display device having a transparent insulating film according to the present invention. Referring to FIG. 1, the flat panel display device 100 includes a substrate 101, an insulating film or a metal thin film 102 formed on the substrate 101, a semiconductor layer 103, an interlayer insulating film 104, and a gate electrode 105. ), A gate insulating film 106, a source / drain electrode 107, a planarization film 108, a protective film 109, a first electrode 110, a light emitting layer 111, and a second electrode 112. The substrate 101 is generally formed of a transparent glass substrate or a plastic substrate, and the thin film transistor formed on the substrate 101 includes a semiconductor layer 103, a gate electrode 105, and a source / drain electrode 107. The light emitting device electrically connected to the thin film transistor includes a first electrode 110, a light emitting layer 111, and a second electrode 112.

Since the other components constituting the flat panel display apparatus are similar to those of the existing components, detailed descriptions thereof will be omitted, and hereinafter, the insulation film 104, which is a characteristic component of the present invention, will be described in detail.

FIG. 2 is an enlarged cross-sectional view of a region of FIG. 1. Referring to FIG. 2, FIG. 2 is an enlarged side view of the insulating film 104 having the refractive index adjusted. The insulating film 104 according to the present invention is formed using two or more kinds of oxide films having different refractive indices. The oxide film used for the insulating film 104 is selected from a silicon oxide film (SiO ₂ ), a titanium oxide film (TiO ₂ ), an aluminum oxide film (Al ₂ O ₃ ), a zirconium oxide film (ZrO ₂ ), a tantalum oxide film (Ta ₂ O ₅ ), and the like. .

Specifically, the refractive index of the silicon oxide film SiO ₂ is about 1.4, the refractive index of the aluminum oxide film Al ₂ O ₃ is about 1.7, and the refractive index of the titanium oxide film TiO ₂ is about 2.4. In particular, titanium oxide (TiO ₂ ) is widely used optically because it maintains electrical insulation and has a relatively large refractive index. In general, the refractive index increases with increasing dielectric constant. The insulating film 104 has a characteristic that the energy band band is large so that light is well transmitted. The insulating film 104 may be manufactured by selecting two types from the above-described oxide film. For example, SiO ₂ -TiO ₂ , Al ₂ O ₃ -TiO ₂ , SiO ₂ -ZrO ₂ , Al ₂ O ₃ -ZrO ₂ , SiO ₂ -Ta ₂ O _5, or the like. As described above, the oxide film constituting the insulating film can be varied in composition. For example, when using a silicon oxide film and a titanium oxide film, if the silicon oxide film is 30% in the overall insulating film composition, 70% of the titanium oxide film is used. If 60% of the silicon oxide film is used, 40% of the titanium oxide film is used.

The insulating film 104 composed of the above two kinds of oxide films is formed by the atomic vapor deposition method. Atomic layer deposition (ALD) uses chemical adhesion to adsorb molecules on the wafer surface and replaces them by alternately adsorbing and replacing them, allowing for ultra-layer-by-layer deposition. It is characterized by stacking oxide and metal thin film as thin as possible. In this embodiment, plasma enhanced atomic layer deposition (PEALD) is used. PEALD is a method of applying a plasma to the existing ALD to lower the process temperature and increase the reactivity between the precursor and the reaction gas to obtain a thin film as thin as possible, it is possible to obtain a thin film of uniform thickness even in a large area. For example, in the case of using PEALD, since it can be uniformly deposited on a wafer having a diameter of about 12 inches at a process temperature of 250 ° C. or less, it can be utilized in a display on a substrate made of an organic material or a plastic.

In the case of using PEALD, the composition of the oxide film constituting the insulating film can be controlled by performing a process of repeatedly obtaining the thin film by controlling the number of deposition cycles. Here, the cycle refers to a step of injecting a source, purging, re-injecting a reaction gas, generating a thin film by chemical reaction on the surface, and purging again in an atomic layer deposition process. The above-described steps (source injection, purge, reactive gas re-injection, thin film formation, repurge step) are the minimum units to be repeated. Here, mixing one cycle for depositing Al ₂ O ₃ material and one cycle for depositing TiO ₂ results in an AlO and TiO cycle ratio of 1: 1. These two cycles are mixed to form a new cycle. An AlTiO thin film is produced. In this case, one cycle of each of Al ₂ O ₃ and TiO ₂ is called a sub-cycle and the cycle ratio is represented as 1: 1 (1,1).

Hereinafter, a description will be given with reference to a graph showing a change in refractive index according to a composition change when two oxide films are mixed.

3A is a graph illustrating a change in refractive index according to a change in content of one component when two oxide films having different refractive indices are mixed. Specifically, FIG. 3B illustrates a refractive index according to a change in titanium content when a titanium oxide film and an aluminum oxide film are mixed. It is a change graph.

The horizontal axis of FIG. 3A represents the content change, and the vertical axis represents the refractive index. Referring to FIG. 3A, the higher the component content, the higher the refractive index. Referring to FIG. 3B, which shows a specific embodiment, the horizontal axis represents a change in content of titanium (Ti / (Ti + Al)), and the vertical axis represents a refractive index according to the change in content. Specifically, when the horizontal axis Ti / (Ti + Al) is 0, the refractive index is 1.7, indicating an aluminum oxide film. When the horizontal axis Ti / (Ti + Al) gradually increases, the refractive index also gradually increases, and the horizontal axis Ti / (Ti When + Al) is 1, the refractive index is 2.4, indicating a titanium oxide film. Referring to the graph, the refractive index varies depending on the content ratio of titanium from 1.7 to 2.4. In conclusion, as shown in FIG. 3B, the titanium oxide film has a refractive index of 2.4 or more, and the aluminum oxide film has a refractive index of about 1.7, and the aluminum oxide film has a refractive index of about 1.7. When controlling the composition of titanium, it is possible to appropriately control the refractive index according to the composition.

4 is a graph showing a change in refractive index with a cycle. Referring to FIG. 4, the horizontal axis represents the cycle ratio of the titanium oxide film and the aluminum oxide film, and the vertical axis represents the refractive index. As shown in the graph, when the cycle ratio of the titanium oxide film and the aluminum oxide film is 0.33, since the cycle number of the titanium oxide film and the aluminum oxide film is 1: 2, the refractive index is about 1.8, and the cycle ratio of the titanium oxide film and the aluminum oxide film is 1 In the case of, since the number of cycles of the titanium oxide film and the aluminum oxide film is 1: 1, the refractive index is approximately 1.9. In the case where the cycle ratio of the titanium oxide film and the aluminum oxide film is 1, the cycle number of the titanium oxide film and the aluminum oxide film is 2: 1, and the refractive index is approximately 2.4. That is, according to the graph of FIG. 4, it is confirmed that the refractive index gradually changes by changing the cycle number of each oxide film.

Generally, the atomic layer deposition method is designed to continuously change the number of TiO and AlO deposition cycles in the middle of the film deposition. Therefore, if the number of TiO deposition cycles is increased, a thin film having a refractive index gradient that continues to increase in Ti content is increased. You can get it. A thin film having such a refractive index gradient has an important optical characteristic of being absorbed in the thin film layer by decreasing the probability of reflection when light enters a layer having a low refractive index and gradually enters a direction of increasing the refractive index. In addition, with ALD, the deposition thickness is very precisely controlled depending on the number of cycles, which is precisely controlled when the deposition thickness is greater than 1 nm. If used for optical purposes, 10nm to 300nm thickness is mainly used, in the present embodiment is deposited to a thickness of approximately 50 ~ 100nm.

5A and 5B are graphs illustrating a change in refractive index according to the thickness of a thin film. According to the graph of FIG. 5A, the horizontal axis is the thickness of the insulating film, and the vertical axis is the refractive index according to the thickness of the insulating film. In FIG. 5A, when the insulating film 104 deposited on the substrate is deposited in a multi-layered form, in particular, the closer to the substrate 101, the higher the refractive index is formed. In addition, the above-described form is to form a large number of interfaces, which is a preferred form for using the insulating film 104 as a light absorption layer.

On the other hand, according to the graph of Figure 5b, the horizontal axis is the thickness of the insulating film, the vertical axis is the refractive index according to the thickness of the insulating film. That is, in FIG. 5B, in the insulating film 104 deposited on the substrate, a layer having a relatively high refractive index is positioned in a sandwich form between layers having a low refractive index. This sandwich type insulating film structure can be effectively used to trap the light flowing from the outside.

6 is a graph showing the reflection characteristics of the insulating film deposited by varying the number of cycles. 6 is a graph showing reflection characteristics of a silicon substrate on which an insulating film is not deposited, and graph (ii) shows a ratio of the number of cycles (TiO / (TiO + AlO)) of 0.67 deposited on a silicon substrate. Graph of reflection characteristics of insulating film, graph shows reflection characteristics of insulation film deposited with ratio of number of cycles (TiO / (TiO + AlO)) at 0.5 on silicon substrate, graph is cycle number on silicon substrate It is a graph of the reflection characteristic of the insulating film which deposited the ratio (TiO / (TiO + AlO)) of 0.33.

According to this graph, the reflection characteristics when the insulating film designed in the present invention is not formed on the silicon substrate are relatively higher than those of the silicon substrates (ii, ⅲ, ⅳ) on which the insulating film is deposited on the substrate. It is confirmed that it is high. According to the graphs (ii), (iii) and (iii), when an insulating film composed of two or more oxide films is deposited on a silicon substrate, not only reflection occurs at a certain wavelength band, but also at a different wavelength band than the silicon substrate. It can be seen that the reflectivity is low. In conclusion, it is preferable to deposit an insulating film having a predetermined refractive index on the substrate in order to reduce the contrast and improve the brightness of the light emitting layer formed on the substrate.

When the insulating film is formed using two or more oxide films having different refractive indices through the above-described manufacturing process, the refractive index may be adjusted using plasma atomic vapor deposition, and the reflection of light flowing from the outside may be reflected by adjusting the refractive index. It can be used as an anti-reflection film. That is, the insulating film manufactured by the method proposed in the present invention may be used by depositing an oxide film having a different composition and a different refractive index depending on the thickness of the insulating film to be deposited. In addition, when an insulating film (for example, AlTiO) deposited by the plasma atomic vapor deposition method is used for the inorganic electroluminescent device so that the refractive index gradually changes, the luminance is improved compared with the light absorbing layer used in the conventional inorganic electroluminescent device. . Accordingly, an insulating film such as AlTiO or TiSiO formed in the above-described process can be used not only as an antireflection film but also as an insulating film between the light emitting layer (fluorescent layer) and the electrode. The insulating film can also be used as both a protective film and an antireflection film, and the insulating film can be used as both a gate insulating film and an antireflection film. That is, there is an advantage that can be manufactured as a transparent anti-reflection film by replacing the insulating film.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the foregoing description, the insulating film whose refractive index is adjusted by using the plasma atomic vapor deposition method may increase contrast by preventing reflection of external light in the display device. In addition, the plasma atom deposition method can be used for various substrates even at low temperatures, and the insulating film can be uniformly deposited regardless of the type of substrate.

In addition, the organic light emitting device may be used as an anti-reflection film in various devices, and the organic light emitting device may serve to protect devices formed on the substrate from moisture or impurities introduced from the outside. Can play a role.

Claims (11)

A plurality of insulating films formed on the substrate; A thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode stacked between one of the plurality of insulating layers; A planarization film formed on the source / drain electrodes; The light emitting device includes a first electrode, a light emitting layer, and a second electrode and is formed on the planarization film. Wherein at least one of the plurality of insulating films is formed by two or more oxide films having different refractive indices by plasma atomic vapor deposition, and controls the content of the oxide film by the number of deposition cycles of the plasma atomic vapor deposition method. The method of claim 1, The oxide film may be selected from a silicon oxide film (SiO ₂ ), a titanium oxide film (TiO ₂ ), an aluminum oxide film (Al ₂ O ₃ ), a zirconium oxide film (ZrO ₂ ) and a tantalum oxide film (Ta ₂ O ₅ ). delete Forming a semiconductor layer, a gate electrode and a source / drain electrode on the substrate; An insulating film is formed on each of the substrate, the semiconductor layer, the gate electrode, and the source / drain electrode, and at least one of the insulating films is formed using plasma atomic vapor deposition to form two or more oxide films having different refractive indices, Adjusting the amount of the oxide film by the number of deposition cycles of the plasma atom deposition method; Forming a light emitting device including a first electrode, a light emitting layer, and a second electrode on an insulating layer formed on the source / drain electrode Method of manufacturing a flat panel display device comprising a. delete delete The method of claim 4, wherein When the insulating film is formed, a flat plate selected from a silicon oxide film (SiO ₂ ), a titanium oxide film (TiO ₂ ), an aluminum oxide film (Al ₂ O ₃ ), a zirconium oxide film (ZrO ₂ ) and a tantalum oxide film (Ta ₂ O ₅ ) is formed. Method for manufacturing a display device. The method of claim 7, wherein A method of manufacturing a flat panel display device which can form a different refractive index by controlling the amount of oxide films constituting the insulating film. The method of claim 8, Method of manufacturing a flat panel display device in which the insulating film is deposited in a single layer or multiple layers The method of claim 9, The insulating film may serve as a protective film and an anti-reflection film. The method of claim 9, And the insulating film serves as a gate insulating film and an anti-reflection film.

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