KR100290136B1 - Method for fabricating field emission display device - Google Patents

Abstract

PURPOSE: A method for fabricating a field emission display device is provided to obtain a high current density under lower voltage by using a diamond thin film. CONSTITUTION: A metal layer is formed sequentially on the first substrate. An insulating layer pattern(62) is formed by applying an insulating material on the metal layer and patterning the insulating material. A diamond or a diamond-like carbon material layer(64) is formed on the metal layer formed with an insulating layer pattern(62). An electrode layer(66) and the second substrate(68) are formed on the diamond-like carbon material layer(64). The electrode layer(66) is formed on the diamond-like carbon material layer(64) by using a vacuum deposition method or a sputtering method or a coating process. The first substrate is separated from the metal layer. A gate electrode is formed by patterning the metal layer.

Description

Field emission emitter and fabrication method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission display device, and more particularly, to a field emission device using a diamond thin film capable of obtaining a high current density under low voltage, and a manufacturing method thereof.

In recent years, field emission displays (hereinafter referred to as FEDs) are being actively researched for application to next-generation flat panel display devices due to advantages such as excellent display characteristics and manufacturing cost competitiveness. The FED displays an image using light generated by colliding electrons emitted from the field emission device with the phosphor. As a field emission element used for such an FED, that is, a field emission emitter, a tip-shaped emitter and an emitter using a flat diamond thin film or diamond-like carbon thin film are mainly used.

Here, the tip-shaped emitter is the most widely applied emitter in FED products and is formed by a rotary deposition method called a spin method.

1A-1D, a cross-sectional view illustrating in stages a process of making a tip shaped emitter is shown.

Referring to FIG. 1A, a structure in which an emitter electrode 12, a resistance layer 14, an insulating pattern 16, and a gate pattern 18 are sequentially stacked on a glass substrate 10 is illustrated. The emitter electrode 12 and the resistive layer 14 are sequentially stacked on the glass substrate 10 by a general coating process. The insulating pattern 16 and the gate pattern 18 may be formed by sequentially stacking an insulating material layer and a gate material layer on the resistive layer 14, and then sequentially patterning the gate layer and the insulating layer by a photolithography process. As shown in 1a, a space a in which the tip is to be formed is provided. Next, as shown in FIG. 1B, metal particles are incident at a predetermined angle (for example, 15 °) while rotating the glass substrate 10 to correspond to the gate pattern 18 by depositing it on the surface of the gate pattern 18. Thus, a separation layer 20 having an opening is formed. Subsequently, as shown in FIG. 1C, as the tip material is incident and deposited in the vertical direction while rotating the substrate 10, the tip material layer 22 is formed on the surface of the separation layer 20 to reduce the opening. In the tip forming space a on the resistive layer 14, a conical tip, that is, an emitter 20a is formed. Then, by removing the separation layer 20 formed to protect the gate pattern 16 and the tip material layer 22 formed thereon, a field emission emitter array having a conical tip 22a as shown in FIG. (FEA) is completed.

However, the above-described emitter manufacturing method has a problem in that it is difficult to control the manufacturing process and is unsuitable for large area, such as lighting to use the rotational deposition process and appropriately adjust the incidence angle in order to adjust the shape of the tip. In addition, as the material forming the tip, a metal such as molybdenum (Mo) is mainly used, and the chemical stability of the metal material becomes a problem.

2A to 2E, there is shown a cross-sectional view illustrating a method of manufacturing an emitter tip by a transfer mold method step by step.

First, as shown in FIG. 2A, the silicon substrate is etched to prepare a silicon mold 24 having a conical groove, and as shown in FIG. 2B, a diamond or other tip is formed on the etched portion of the silicon mold 24. The material layer 26 is formed. Next, as shown in FIGS. 2C and 2D, the emitter electrode 28 is formed on the tip material layer 26, and the glass substrate 30 is bonded to the emitter electrode 28. As shown in FIG. 2E, the silicon mold 24 under the tip material layer 26 is removed by an etching process to complete the field emission emitter.

3A to 3F, there is shown a cross-sectional view for explaining step by step a field emission emitter manufacturing process disclosed in Japanese Patent Laid-Open No. 9-259740 as another emitter manufacturing process.

In FIG. 3A, after the oxide film formed by oxidizing only the surface of the silicon substrate is appropriately patterned, the silicon substrate 32 is formed by etching the silicon substrate using the oxide film pattern 34 to form a triangular groove. Next, boron ions are injected while rotating the silicon mold 32 at a predetermined angle to form a boron diffusion layer forming the gate electrode 36 on the silicon mold 32 as shown in FIG. 3B. The surface of the gate electrode 36 is oxidized to form an insulating layer 38 having a uniform thickness as shown in FIG. 3C. Subsequently, by forming a tip material layer on the insulating layer 38, as shown in FIG. 3D, the emitter electrode 40 and the tip 40a corresponding to the groove of the silicon mold 32 are formed. Then, the glass substrate 42 is bonded to the surface of the emitter electrode 40 as shown in FIG. Finally, in FIG. 3E, only the silicon mold 32 on the gate electrode 36 is selectively removed. As a result, as shown in FIG. 3F, the emitter electrode 40 and the emitter tip 40a sequentially formed on the glass substrate 42 and the inclined surfaces of the emitter tip 40a are sequentially captured. An emitter array consisting of the stacked insulating layer 38 and the gate electrode 36 is completed.

However, the method of manufacturing the emitter using the silicon mold is not suitable for mass production and large area because the material of the substrate is limited to silicon and the silicon substrate must be precisely controlled and the silicon substrate must be finally removed. There is this. In particular, the emitter manufacturing process shown in FIG. 3 has a difficulty in precisely controlling the diffusion thickness of the oxide film and the boron layer.

In addition, the tip-type emitter described above has the disadvantage of being chemically unstable while having a good field emission efficiency. In other words, as a tip material, a metal that is relatively rigid and easy to manufacture, such as molybdenum (Mo) and silicon (Si), is generally used. These metal materials have disadvantages of being chemically unstable in the tip state. For this reason, a method of implementing an emitter using diamond or diamond-like carbon having chemically stable characteristics and electron emission at a low applied voltage in a planar state as well as a tip state has been attempted. In particular, the diamond or diamond-like carbon is excellent in chemical stability and has the advantage of maintaining the initial electron emission efficiency more stably.

However, such diamond or diamond-like carbon has a disadvantage in that the fine patterning required by the FED is difficult because of excellent chemical stability. In other words, diamond and diamond-like carbon are difficult to etch, and thus it is difficult to obtain a desired pattern. Therefore, in order to facilitate the patterning of diamond and diamond-like carbon, a method of forming a pattern by pretreating only a desired portion with diamond microparticles or the like before vapor phase chemical vapor deposition and selectively forming only this portion during deposition is mainly used. It is becoming. However, the chemical vapor deposition method has a problem in that it is difficult to control the electron emission characteristic because the surface of the film having a large influence on the electron emission characteristic is not uniform while it is a method suitable for diamond thin film growth. In other words, diamond electron emission emitters are highly limited in their application due to non-uniformity of electron emission sites. In particular, there are many difficulties in controlling the electron emission site by the nonuniformity of the surface state.

4, a cross-sectional view of one cell in the FED using the above-described diamond thin film is shown. The FED cell shown in FIG. 4 includes a plurality of diamond thin film patterns 50 formed on the emitter electrode 49 and the phosphor 52 coated on the bottom surface of the upper substrate 54.

In the FED cell shown in FIG. 4, when a voltage is applied between the emitter electrode 49 and the anode electrode formed on the phosphor 52, electrons are emitted from the patterned diamond thin film 50. These emission electrons strike light at the upper portion of the phosphor 52 to generate light. As such, most of the diamond electron emission emitters currently used are formed on the surface of the diamond thin film pattern 50 grown only on a specific portion 48a on the substrate 48 (or the emitter electrode) as shown in FIG. Electron emission characteristics are used.

However, as the diamond thin film 50 grows, the grain size grows differently, and as shown in FIG. 5, the sharp portions of the surface are unevenly distributed, so it is difficult to expect uniform electron emission from the surface. In addition, since diamond thin film growth is performed at a high temperature of more than several hundred degrees, glass substrates cannot be used, which is not suitable for large area.

Accordingly, it is an object of the present invention to provide a field emission emitter and a method of manufacturing the same, which can refine a diamond thin film into a desired pattern.

Another object of the present invention is to provide a field emission emitter and a method of manufacturing the same, which can implement a high efficiency FED capable of large area.

It is still another object of the present invention to provide a field emission emitter and a method of manufacturing the same, wherein the surface state of the diamond thin film pattern is almost the same and the electron emission characteristic is easily controlled.

Still another object of the present invention is to provide a field emission emitter and a method of manufacturing the same, which can reduce the manufacturing cost by simplifying the manufacturing process.

1A to 1D are cross-sectional views illustrating a conventional tip-shaped emitter manufacturing method step by step.

2A to 2E are cross-sectional views illustrating stepwise methods of manufacturing a tip-shaped emitter by a conventional transfer mold method.

3A to 3F are cross-sectional views illustrating another conventional emitter manufacturing method step by step.

Figure 4 is a cross-sectional view showing the structure of one cell in the FED using a conventional diamond film emitter.

5 is a cross-sectional view showing a surface of a conventional diamond thin film emitter.

6A through 6E are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter in accordance with a first embodiment of the present invention.

7A through 7E are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter according to a second exemplary embodiment of the present invention.

8 is a cross-sectional view illustrating a structure of a diamond electron emission emitter according to a third exemplary embodiment of the present invention.

9A to 9E are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter in accordance with a fourth embodiment of the present invention.

10A to 10G are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter in accordance with a fifth embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

10, 30, 54, 48, 58, 68, 76, 88: glass substrate

12: resistive layer 14, 28, 40, 49, 66, 86: emitter electrode

16, 56, 62, 82: insulating layer pattern 18, 60a, 72, 74, 80a: gate pattern

20, 78: separation layer 22, 26: tip material layer

22a: emitter tip 24, 32: silicon substrate

50, 64, 70, 84, 84a: diamond thin film

52 phosphor 48a pretreatment surface

34, 38: oxide film 36: boron diffusion layer

60, 80: gate layer 78: separation layer

In order to achieve the above objects, the field emission emitter according to the present invention comprises an emitter electrode commonly formed on an arbitrary substrate, a planar emitter formed on the emitter electrode surface to emit electrons, and formed above the emitter voltage And a patterned gate electrode formed between the emitter and the gate electrode, the gate electrode patterned to apply the electrode.

The method of manufacturing a field emission emitter according to the present invention includes a first step of sequentially forming a gate layer and an insulating layer pattern on a first substrate, and a second step of forming a planar emitter on a gate layer on which an insulating layer pattern is formed. And a third step of sequentially forming an emitter electrode and a second substrate on the emitter, and a fourth step of patterning the gate layer after separating the first substrate.

In addition, the method for manufacturing a field emission emitter according to the present invention includes a first step of forming a separation metal layer on a first substrate, a second step of sequentially forming a gate pattern and an insulating layer pattern on the separation metal layer, and a gate pattern. And a third step of forming a planar emitter on the separation metal layer on which the insulating layer pattern is formed, a fourth step of sequentially forming the emitter electrode and the second substrate on the emitter, and separating and separating the first substrate. And a fifth step of etching the metal layer.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 6 to 10.

6A through 6E are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter according to a first embodiment of the present invention.

Referring to FIG. 6A, a metal layer 60 and an insulating layer pattern 62 sequentially stacked on the substrate 58 are illustrated. It is formed on the substrate 58 by a conventional coating process of the metal layer 60. At this time, the metal layer 60 and the substrate 58 are processed to be separated at an appropriate time. For example, a stainless thin film or chromium thin film is formed on the substrate 58 using a sputtering process, and then a metal layer 60 made of nickel (Ni), tungsten, or the like is formed on the stainless thin film using an electroplating process. . In this case, by applying an appropriate physical force, the substrate 58 on which the stainless thin film is formed may be separated from the metal layer 60 made of nickel or the like. The insulating layer pattern 62 is formed by applying an insulating material on the metal layer 60 and then patterning the pattern appropriately by an etching process.

As shown in FIG. 6B, the diamond or diamond-like carbon material layer 64 is easily formed on the metal layer 60 having the insulating layer pattern 62 formed thereon. At this time, the diamond thin film may be doped with appropriate impurities in order to smoothly supply electrons. Here, it is more preferable to dope with n type impurity with a high electron level. It is also possible to pretreat only desired portions of the metal layer 60 on the substrate 58 to facilitate nucleation of the diamond prior to diamond formation.

When the diamond thin film 64 is formed to an appropriate thickness, the electrode layer 66 and the second substrate 68 are formed on the diamond thin film 64 as shown in FIG. 6C. The electrode layer 66 is formed on the diamond thin film 64 as an emitter electrode by a vacuum deposition method, a sputtering method or other coating process. The second substrate 68 is formed by bonding a plate made of glass or other material to the emitter electrode 66.

Referring to FIG. 6D, an emitter array separated from the first substrate 58 in the structure as shown in FIG. 6C is shown. The first substrate 58 is separated from the metal layer 60 by appropriate physical forces, and the superstructure including the metal layer 60 is used as an emitter array.

Referring to FIG. 6E, an emitter electrode 66, a diamond thin film 64, and an insulating layer pattern sequentially stacked on the second substrate 60 as a structure in which the emitter array shown in FIG. 6D is vertically reversed. An emitter array having 62 and a gate pattern 60a formed on the insulating layer pattern 62 is shown. The gate pattern 60a is formed by suitably patterning the insulating layer pattern 62 and the metal layer 60 formed on the diamond thin film 64 to have a predetermined step with the lower insulating layer pattern 62 by an etching process. It is done. The surface portion of the diamond thin film 64 exposed by this etching process can remove the graphite component using hydrogen plasma and induce more defects, thereby making electron emission easier.

7A through 7E, cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter according to a second exemplary embodiment of the present invention are shown. Here, the diamond thin film 64 of the electron-emitting emitter shown in Fig. 6E is formed in the form of a continuous film, while the diamond thin film 70 of the electron-emitting emitter shown in Fig. 7E is already formed by the insulating layer pattern 62. It can be seen that the ruins are formed in a separate form. This can be achieved by controlling the growth thickness to have the same thickness as the insulating layer pattern 62 when the diamond thin film is grown on the metal layer 60 on which the insulating layer pattern 62 is formed. Hereinafter, other processes are the same as described above, so a description thereof will be omitted.

8 is a cross-sectional view illustrating a structure of a diamond electron emission emitter according to a third exemplary embodiment of the present invention.

The field emission emitter shown in FIG. 8 includes an emitter electrode 66 formed on the substrate 68, an insulating layer pattern 62 and a diamond thin film pattern 70 stacked on the emitter electrode 66, A pair of gate patterns 72 are provided to enable electron emission from the two diamond thin film patterns 70. Here, electrons are emitted from the plurality of diamond thin film patterns, that is, the emitter 70, by the voltage applied to the emitter electrode 66 and the pair of gate patterns 72.

9A through 9E are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 9A, a structure in which a metal layer 60 and a gate pattern 74 and an insulating layer pattern 62 having a shape surrounding the gate pattern 74 is sequentially stacked on the first substrate 58 is illustrated. have. It is formed on the substrate 58 by a conventional coating process of the metal layer 60 and treated to be separated by an appropriate physical force. The gate pattern 74 is formed by forming a gate material layer on the metal layer 60 and then patterning it in a desired pattern by an etching process. The insulating layer pattern 62 is formed by coating an insulating material on the metal layer 60 on which the gate pattern 74 is formed, and then patterning the insulating layer pattern 62 to surround the gate pattern 74 by an etching process.

A diamond or diamond-like carbon material layer 64 is formed to an appropriate thickness on the metal layer 60 on which the insulating layer pattern 62 is formed, as shown in FIG. 9B.

As shown in FIG. 9C, the emitter electrode 66 is bonded to the diamond thin film 64, and the second substrate 68 is bonded thereto.

The lower first substrate 58 then exerts an appropriate physical force to separate it from the superstructure including the metal layer 60, ie the emitter array, as shown in FIG. 9D.

Finally, the metal layer 60 located on the upper portion of the gate pattern 74 is removed in the structure of inverting the vertical position of the emitter array shown in FIG. 9D. Accordingly, as shown in FIG. 9E, the emitter electrode 66, the diamond thin film 64, the insulating layer pattern 62, and the insulating layer pattern 62 that are sequentially stacked on the second substrate 60 are disposed. The emitter array including the gate pattern 74 in the captured state is completed. Here, it is also possible to partially etch the insulating layer pattern 62 between the diamond thin film 64 and the gate pattern 74.

10A through 10H are cross-sectional views illustrating a method of manufacturing a diamond electron emission emitter according to a fifth exemplary embodiment of the present invention.

Referring to FIG. 10A, a structure in which a separation layer 78, a gate layer 80, and an insulating layer pattern 82 are sequentially stacked on a first substrate 76 is illustrated. The separation layer 78 is formed by treating the separation layer 78 so as to be separated from the first substrate 76. For example, a stainless thin film or chromium thin film is formed on the first substrate 76 so as to be separated by a predetermined physical force, and then made of nickel (Ni) or tungsten using an electroplating process on the stainless thin film. Separation layer 78 is formed. The gate layer 80 is formed on the separation layer 78 by a conventional coating process. The insulating layer pattern 82 is formed by applying an insulating material on the gate layer 80 and then patterning the pattern appropriately by an etching process.

The gate layer 80 exposed through the insulating layer pattern 82 is etched to form a gate pattern 80a between the isolation layer 78 and the insulating layer pattern 82 as shown in FIG. 10B.

Subsequently, a diamond thin film 84 is formed on the separation layer 78 and the insulating layer pattern 82 exposed through the gate pattern 80a as shown in FIG. 10C. The diamond thin film pattern 84 is formed on the separation layer 78 and the insulating layer pattern 82 by vapor phase chemical vapor deposition or vapor phase physical vapor deposition. Here, in the case of using the chemical vapor deposition method, the exposed portion of the separation layer 78 may be pretreated to facilitate diamond nucleation. In addition, in the case of using the chemical vapor deposition method, a carbon component may be formed in the stepped portion 80b between the insulating layer pattern 82 and the gate pattern 80a, but the carbon component may be later removed using hydrogen plasma. .

Next, an emitter electrode 86 is formed on the diamond thin film 84 as shown in FIG. 10D, and then a second substrate 88 made of glass or other material is bonded to the emitter electrode 86. .

When the second substrate 88 is bonded onto the emitter electrode 86, a predetermined physical force is applied to the lowermost first substrate 76 and the separation layer 78, thereby as shown in FIG. 10E. 76) and a superstructure comprising a separation layer 78, ie an emitter array.

Then, the separation layer 78 formed under the gate pattern 80a is removed by an etching process, and the upper and lower positions are reversed. As shown in FIG. 10F, the surface of the diamond thin film 84 and the surface of the gate pattern 80a are removed. Complete the emitter array located on this same face.

Here, the diamond thin film 84 exposed between the gate patterns 80a may be properly etched using hydrogen plasma or other suitable plasma as shown in FIG. 10G. In this case, when voltage is applied to the emitter electrode 86 and the gate pattern 80a, electron emission occurs from the surface of the diamond thin film 84a positioned between the insulating layer pattern 82. The electrons emitted from the diamond thin film 84a are accelerated by the voltage applied to the anode electrode on which the phosphor disposed separately is applied to collide with the phosphor to generate light unique to the phosphor.

As described above, according to the field emission emitter and the method of manufacturing the same according to the present invention, it is possible to facilitate the control of the electron emission characteristics by using the uniform thin film surface grown at the beginning of the diamond thin film as the electron emission surface. Accordingly, by using a uniform diamond thin film having low voltage driving characteristics, a high efficiency FED can be realized and a large area can be achieved. In addition, the manufacturing cost can be reduced by using the low voltage driving characteristics of the diamond thin film itself.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (19)

A first step of sequentially forming a gate metal layer and an insulating layer on the first substrate and patterning the insulating layer in a desired shape to form an insulating layer pattern; A second step of forming an emitter made of diamond or diamond-like carbon thin film on the gate metal layer having the insulating layer pattern formed thereon; A third step of sequentially forming an emitter electrode and a second substrate on the emitter; And separating the first substrate and patterning the gate metal layer to form a gate electrode. The method of claim 1, The first step is And forming a metal thin film easily separated from the gate metal layer on the first substrate. The method of claim 1, The second step is And doping an impurity into the emitter to facilitate electron emission. The method of claim 1, The emitter is formed using any one of the vapor phase physical vapor deposition method and vapor phase chemical vapor deposition method, In the case of using the chemical vapor deposition method, before the exposed surface of the gate metal layer to facilitate the growth of the emitter, the field emission device manufacturing method characterized in that. The method of claim 1, And growing the emitter to capture the insulating layer pattern. The method of claim 1, And growing the emitter so as to be separated by the insulating layer pattern. The method of claim 1, The gate electrode is a field emission device manufacturing method, characterized in that formed to apply an electric field to one emitter. The method of claim 1, And the gate electrode is formed to apply an electric field to a plurality of emitters. The method of claim 1, The fourth step is And plasma processing the surface of the device exposed through the gate electrode to facilitate electron emission. Forming a separation metal layer on the first substrate; A second step of sequentially forming a gate pattern and an insulating layer pattern on the separation metal layer; Forming an emitter of a diamond or diamond-like carbon thin film on the separation metal layer on which the gate electrode and the insulating layer pattern are formed; A fourth step of sequentially forming a device electrode and a second substrate on the device; And a fifth step of etching the separated metal layer after separating the first substrate. The method of claim 10, The gate electrode is formed by forming a gate metal layer on the separation metal layer and patterning to a desired shape, The insulating layer pattern is a field emission production method, characterized in that to form an insulating layer on the separated metal layer on which the gate electrode is formed and then pattern the gate electrode to capture. The method of claim 11, Step 5 is And partially etching the insulating layer pattern between the gate electrode and the device. The method of claim 10, The second step is Sequentially forming a gate layer and an insulating layer on the separation metal layer; Patterning the insulating layer to form the insulating layer pattern; And etching the gate metal layer inwardly through the insulating layer pattern to form the gate electrode. The method of claim 13, And etching the surface of the device exposed through the gate electrode to have a predetermined step with the surface of the insulating layer pattern. The method of claim 10, The third step is A method of manufacturing a field emission device further comprising the step of doping the device to facilitate electron emission. The method of claim 10, The emitter is formed using any one of the vapor phase physical vapor deposition method and vapor phase chemical vapor deposition method, In the case of using the vapor phase physical vapor deposition method, before the exposed surface of the gate electrode to facilitate the growth of the emitter, the field emission device manufacturing method characterized in that. The method of claim 10, And growing the device to capture the insulating layer pattern. The method of claim 10, And growing the device to be separated by the insulating layer pattern. The method of claim 10, And plasma-processing the surface of the device exposed through the gate electrode to facilitate electron emission.