KR100400374B1 - Method Of Fabricating Field Emission Device and Field Emission Display Using The Same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a field emission device for simplifying a manufacturing process of a MIM field emission device, and a field emission display device using the same.

The manufacturing method of the field emission device and the field emission display device using the same are patterned by irradiating a laser beam to the top electrode.

Description

Method of manufacturing field emission device and field emission display device using same Field of Fabrication Field Emission Device and Field Emission Display Using The Same

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission device, and more particularly, to a method of manufacturing a field emission device for simplifying a manufacturing process of a MIM type field emission device.

As field emission devices are applied to display devices, the development of a thin cathod ray tube (hereinafter, referred to as "thin CRT"), which can be manufactured in a light and simple manner, is being accelerated. The field emission display device (hereinafter referred to as "FED") is thin and can display an image with a wide viewing angle characteristic and high luminance and clarity similar to that of a conventional CRT. FED can be applied to almost all displays, from small resolution to high resolution, including notebook PCs and projection TVs.

FED uses electron beam-excited phosphor emission like a cathode ray tube to concentrate electrons in sharp emitters to emit electrons with quantum mechanical tunnel effects. The electrons emitted from the emitter are accelerated by the voltage between the anode and the cathode and collide with the phosphor film formed on the anode to emit the phosphor.

1 illustrates a spindt type field emission device using a metal tip (molybdenum: MO) used as an emitter of an FED.

Referring to FIG. 1, a spin type field emission device includes a cathode electrode 4 formed on a substrate 2, an emitter tip 10 formed in a cone shape on the cathode electrode 4, and a tip 10. An insulating layer 6 formed over the cathode electrode 4 and a gate electrode 8 formed over the insulating layer 6; The cathode electrode 4 accelerates the electrons emitted from the emitter tip 10 toward the anode electrode (not shown). The emitter tip 10 emits electrons when a high field is applied to itself by the cathode electrode 4. The gate electrode 8 is used as an extraction electrode for emitting electrons.

A method of manufacturing the field emission device illustrated in FIG. 1 will be described step by step with reference to FIGS. 2A to 2F.

As shown in FIG. 2A, a cathode electrode material layer 4a is formed on the substrate 2 and an insulating material for insulating between the emitter tip 10 and the gate electrode 8, for example, SiO _2, is plasma enhanced chemical vapor deposition ( After forming the insulating material layer 6a by depositing with Plasma Enhanced Chemical Vapor Deposition, or the like, a gate electrode material such as molybdenum (Mo), tantalum (Ta), niobium (Nobium), chromium (Cr) Any one of them is selected to form the gate electrode material layer 8a by sputtering.

In FIG. 2B, a photo resist mask (PR Mask) is aligned on the substrate 2 on which the cathode electrode material layer 4a, the insulating material layer 6a, and the gate electrode material layer 8a are formed and reacted with the ion. Reactive Ion Etching (RIE) is performed to form an annular gate hole on the gate electrode material layer 8a by dry etching.

In FIG. 2C, a tip formation space is formed between the insulating layer material layer 6a and the gate electrode material layer 8a by an etching process for the insulating material layer 6a.

In FIG. 2D, a sacrificial layer material of any one of nickel (Ni) and argon (Ar) is rotated to be deposited using an E-beam to form a sacrificial layer 12 on the gate electrode material layer 8a. do. Here, the angle between the substrate 2 and the beam source is controlled at an angle of 75 degrees. Since the hole diameter of the sacrificial layer 12 has a decisive influence on the tip shape, the angle of the E-beam must be precisely controlled.

In FIG. 2E, when molybdenum (Mo) is vertically rotated onto the glass substrate 2 using an E-beam, molybdenum (Mo) is deposited and molybdenum (Mo) is also deposited on the cathode electrode 4. As it proceeds, the hole diameter of the molybdenum layer Mo deposited on the sacrificial layer 12 decreases, so that the emitter tip 10 in the form of a cone is formed on the cathode electrode 4.

Finally, the sacrificial layer 12 is removed by an electrochemical method as shown in FIG. 2F.

In the conventional method of manufacturing a field emission device, if the field emission device can be manufactured with high efficiency, but the deposition angle of the E-beam is not precise when the sacrificial layer 12 is deposited, the hole diameter of the sacrificial layer 12 is uneven. Shape irregularities between emitter tips 10 of adjacent pixel cells may appear. In addition, since the molybdenum (Mo) should be deposited perpendicularly to the substrate 2 when forming the conical emitter, that is, because the angle of incidence of the beam to the substrate 2 is small, There is a problem that the height of the equipment is bound to be high.

Recently, planar emitters have been developed to overcome the problems of the spin type emitter manufacturing process. Planar emitters are those using Diamond Like Carbon (DLC), Surface Conduction Emitter, Metal-Insulator-Metal (hereinafter referred to as "MIM"), Bali Stickistic electron surface emitting devices (hereinafter referred to as "BSD") and the like have been developed.

MIM and BSD emitters do not require high vacuum and do not require a separate configuration for focusing. In addition, MIM and BSD emitters have a drive voltage of 20V or less and are resistant to surface contamination.

The MIM emitter is a structure in which a thin insulating layer exists between the cathode electrode and the gate electrode. In the MIM emitter, when a voltage is applied to the gate electrode, electrons having a higher energy than the work function of the gate electrode are emitted toward the anode electrode (not shown), which tunnels the thin insulating layer and discharges the phosphor on the anode electrode. It will emit light.

The manufacturing method of the MIM emitter includes a process as shown in FIGS. 3A to 3J.

Referring to FIG. 3A, after a metal in which copper (Cu), tantalum (Ta), and neodymium (Nd) are mixed with aluminum (Al) is deposited on the glass substrate 32, the mask is aligned, and the exposure and The mixed metal layer is patterned by the developing process and the wet etching process.

The photoresist pattern 36 is formed on the center portion of the cathode electrode (or base electrode) 34 formed as shown in FIG. 3B, and tarta acid and NH _{4 in} ethylene glycol solution as shown in FIG. 4. The back is dipping into the mixed solution 40. 4, an electric field is applied to the anodizing electrode 38 and the cathode electrode 34 facing the glass substrate 32. Then, as illustrated in FIG. 3C, an insulating layer 42 made of Al ₂ O ₃ is formed on both sides of the cathode electrode 34 which is not masked by the photoresist pattern 36.

Subsequently, after the photoresist pattern 36 is removed as shown in FIG. 3D, anodization is performed again to form a thin tunneling insulating film 44 between the insulating layers 42 on the side surfaces.

On the glass substrate 32 on which the tunneling insulating film 44 is formed, tungsten (W) and aluminum (Al) are continuously deposited to a thickness of about 100 mW and about 3000 m as shown in FIG. 3E. As a result, the tungsten layer 46 and the aluminum layer 48 covering the cathode electrode 34, the insulating layer 42, and the tunneling insulating film 44 are formed on the glass substrate 32. The tungsten layer 46 serves to increase the bonding force between the aluminum layer 48 and the insulating layer 42.

On the glass substrate 32 on which the tungsten layer 46 and the aluminum layer 48 are formed, a third mask (not shown) is aligned, and the tungsten layer 46 and the aluminum layer are exposed as shown in FIG. 3F by an exposure and developing process and a wet etching process. 48 is patterned.

The SiNx layer 50 is entirely deposited on the glass substrate 32 on which the tungsten layer 46 and the aluminum layer 48 are patterned, as shown in FIG. 3G.

Subsequently, a fourth mask (not shown) is aligned on the SiNx layer 50 as shown in FIG. 3H, and the SiNx layer 50 is patterned by an exposure and development process and an etching process. As a result, the field emission holes 52a which are perpendicular to the tunneling insulating film 44 are formed on the SiNx layer 50.

The glass substrate 32 on which the field emission holes 52a are formed is dipped in an etchant reacting with aluminum. Then, the aluminum layer 48 is etched as shown in FIG. 3I using the SiNx layer 50 as a mask. Here, the aluminum layer 48 is further etched inwardly than the stepped portion of the SiNx layer 50 forming the sidewall of the field emission hole 52a. Accordingly, the stepped portion of the SiNx layer 50 protrudes more than the etching surface of the aluminum layer 48 so that the aluminum layer 48 and the field emission hole 52a in the field emission hole 52a form an overhang structure 52b. Have.

The glass substrate 32 in which the SiNx layer 50 and the aluminum layer 48 are etched in an overhang structure is dipped in an etchant reacting with tungsten. Then, the tungsten layer 46 is etched using the SiNx layer 50 as a mask to expose the tunneling insulating film 44 in the field emission hole 52a.

On the glass substrate 32 on which the tunneling insulating film 44 is exposed, as shown in FIG. 3K, a metal having high conductivity and strong surface contamination on any one of gold (Au), platinum (Pt) and iridium (Ir) is deposited on the gate electrode (Or top electrodes) 54a and 54b are formed. At this time, the gate electrode 54b on the SiNx layer 50 and the gate electrode 54a on the tunneling insulating film 44 are separated by the overhang structure SiNx layer 50 and the aluminum layer 48 to maintain an insulated state. Done. Thus, the overhang structure separates adjacent gate electrode lines from each other without requiring a separate patterning process.

Since the MIM emitter must pass through the gate electrode (top electrode) 54a in the field emission hole 52a to be accelerated toward the anode electrode (not shown), when the gate electrode 54a is thick, electrons are difficult to penetrate and thin. The resistance is large and cannot serve as an electrode. For this reason, the thickness of the gate electrodes 54a and 54b is set to around 100 microseconds, but it is difficult to pattern them. That is, when the SiNx layer 50 and the aluminum layer 48 are etched in the overhang structure as described above, the formation process of the SiNx layer 50 on the tungsten layer 46 and the aluminum layer 48, and the SiNx layer ( Since the patterning process of 50), the etching process of the aluminum layer 48, etc. have to be added, the number of processes increases by that much and the process becomes complicated. In addition, the SiNx layer 50 has a problem in that the bonding strength with the aluminum layer 48 is weak due to the residual stress due to the difference in thermal expansion coefficient with the aluminum layer 48, which is a lower layer thereof, and thus the film separation occurs easily.

Alternatively, the gate electrode can be patterned using a lift-off method, but in this case, a photoresist pattern is used. When the photoresist pattern is removed by this method, since the photoresist pattern is stripped by the organic solvent material, the thin gate electrode is easily damaged by the organic solvent material.

Similar to the MIM emitter, the BSD emitter has a structure in which a polysilicon layer 66 exists between the cathode electrode 64 and the gate electrode 68 as shown in FIG. 5. In the BSD emitter, when a voltage is applied to the gate electrode 68, an anode electrode of which electrons having a higher energy than the work function of the gate electrode 68 among the electrons tunneled through the polysilicon layer 66 is not shown. Is emitted toward the light emitting phosphor on the anode.

However, the BSD emitter forms an oxide film 66a of SiO ₂ on each of the polysilicon particles as shown in FIG. 6 by oxidizing the polysilicon particles, but since the oxide film forming process is difficult, it is difficult to actually implement.

Accordingly, an object of the present invention is to provide a method for manufacturing a field emission device to simplify the manufacturing process of the MIM field emission device.

Another object of the present invention is to provide a field emission display device manufactured using the manufacturing process.

1 is a schematic longitudinal cross-sectional view showing the operation principle of a conventional spin type field emission display.

2A to 2F are cross-sectional views illustrating a method of manufacturing the spin type field emission device shown in FIG. 1.

3A to 3K are cross-sectional views illustrating a method of manufacturing a conventional MIM emitter.

4 is a cross-sectional view showing an anodizing process.

5 is a cross-sectional view showing the structure of a conventional BSD emitter.

FIG. 6 is a cross-sectional view showing an upper film coated on the polysilicon particles shown in FIG. 5. FIG.

7A to 7I are cross-sectional views showing a field emission device according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a state in which a gate electrode (top electrode) is patterned by the laser trimming method shown in FIG. 7I together with adjacent lines; FIG.

9 is a cross-sectional view showing a method for reducing the spot diameter of a laser beam in the laser trimming method.

<Description of Symbols for Main Parts of Drawings>

2,32,62,72: substrate 4,34,64,74: cathode electrode

6,42,82: insulating layer 8,54a, 54b, 68,94: gate electrode

36,76 photoresist pattern 44,84 tunneling insulating film

46,86 tungsten layer 48,88 aluminum layer

50: SiNx layer 52a, 92: field emission hole

52b: overhang structure 66: polysilicon 66a: oxide film 96: laser beam

In order to achieve the above object, the method of manufacturing a field emission device according to the present invention comprises the steps of forming a base electrode on the substrate, forming an insulating layer on the base electrode, and the gate electrode in a direction perpendicular to the base electrode Forming a pattern, patterning a portion of the gate electrode to be electron-emitted, forming a top electrode on the portion to be emitted, and selectively irradiating a portion of the top electrode by irradiating a laser beam to the top electrode And patterning the top electrode by removing the top electrode. In a field emission display device having a base metal-insulating layer-top metal structure, the top metal is patterned by being selectively removed by a laser beam irradiated to the top metal. It is characterized by.

Other objects and advantages of the present invention in addition to the objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 7A to 9.

Referring to FIG. 7A, in the method of manufacturing a field emission device according to the present invention, a metal in which copper (Cu), tantalum (Ta), and neodymium (Nd) is mixed with aluminum (Al) is formed on a glass substrate 72. After the entire surface deposition, the mask is aligned on the glass substrate 72, and the mixed metal layer is patterned through an exposure and development process and a wet etching process.

The photoresist pattern 76 is formed on the center portion of the cathode electrode (or base electrode) 74 formed as shown in FIG. 7B and anodized as shown in FIG. 4. Then, as shown in FIG. 7C, insulating layers 82 made of Al ₂ O ₃ are formed on both sides of the cathode electrode 74 which is not masked by the photoresist pattern 76.

Subsequently, after the photoresist pattern 76 is removed as shown in FIG. 7D, anodization is performed again to form a thin tunneling insulating layer 84 between the insulating layers 82 on the side surfaces.

On the glass substrate 72 on which the tunneling insulating film 84 is formed, tungsten (W) and aluminum (Al) are continuously deposited to a thickness of about 100 mW and about 3000 m as shown in FIG. 7E. As a result, a tungsten layer 86 and an aluminum layer 88 are formed on the glass substrate 72 to cover the cathode electrode 74, the insulating layer 82, and the tunneling insulating layer 84. The tungsten layer 86 serves to increase the bonding force between the aluminum layer 88 and the insulating layer 82.

On the glass substrate 72 having the tungsten layer 86 and the aluminum layer 88 formed thereon, a third mask (not shown) is aligned and perpendicular to the tunneling insulating layer 84 as shown in FIG. 7F by an exposure and developing process and a wet etching process. The center portion of the opposing aluminum layer 88 is removed to form the field emission holes 92.

On the glass substrate 72 in which the field emission holes 92 are formed, the fourth mask is aligned as shown in FIG. 7G, and the tungsten layer 86 in the field emission holes 92 is removed by the exposure and development process and the wet etching process. The tunneling insulating film 84 of the portion is exposed. Here, the tungsten layer 86 may be etched using the aluminum layer 88 as a mask without using a separate mask.

Subsequently, as shown in FIG. 7H, a metal having high conductivity and strong surface contamination on any one of gold (Au), platinum (Pt), and iridium (Ir) is deposited on the glass substrate 72 to form a gate electrode (or a top electrode) ( 94 is formed.

Finally, the gate electrode 94 is patterned by irradiating a laser beam 96 as shown in FIG. 7I to separate adjacent gate electrode lines as shown in FIG. 8.

The laser patterning method trims the gate electrode 94 by focusing a laser source with an objective lens so that the light spot of the laser beam follows the trajectory between adjacent gate electrode lines as shown in FIG. 7I. . Here, the energy of the laser beam is determined according to the composition and material properties of the gate electrode material so that the glass substrate 72 can be removed without damaging the glass substrate 72. In addition, since the laser beam incident on the objective lens is incident through the mirror, the laser beam is focused by the objective lens by controlling the incident light angle of the objective lens using a galvanomirror driven by an electrical signal. By finely controlling the light spot of the laser beam, it is possible to trim the fine pattern of the gate electrode line.

When the width between the gate electrode lines is very small, the laser beam is irradiated only to a desired minute position by using a mask 98 having an opening smaller than the diameter of the laser beam as shown in FIG. Can be reflected.

As the light source, a gas laser such as He-Ne, Ar ion, Co ₂ , or an excimer, a semiconductor laser such as II-IV or III-V materials, or a solid state laser such as YAG may be used.

The gate electrode 94 was trimmed using a laser beam, and the resistance between adjacent gate electrode lines was measured to be equal to or more than MΩ, thereby exhibiting similar insulation characteristics to the conventional lift-off method or the patterning method using an overhang structure.

As described above, in the method of manufacturing the field emission device and the field emission display device using the same, the insulating layer SiNx for the overhang structure is unnecessary by trimming and patterning the gate electrode (or the top electrode) using a laser. The patterning process using the photoresist caused by the lift-off method is unnecessary, and damage to the gate electrode can be prevented by the organic solution for removing the photoresist pattern. In addition, the method of manufacturing the field emission device and the field emission display device using the same according to the present invention require only three or four masks, compared to the conventional MIM emitter manufacturing process requiring five masks. The time will be greatly reduced. Therefore, the method of manufacturing the field emission device and the field emission display device using the same according to the present invention can prevent the electrode from being damaged by the patterning process and can simplify the manufacturing process of the MIM type field emission device.

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 (4)

Forming a base electrode on the substrate; Forming an insulating layer on the base electrode; Forming a gate electrode in a direction perpendicular to the base electrode; Patterning a portion where electrons are to be emitted to the gate electrode; Forming a top electrode on the portion to be emitted; And patterning the top electrode by selectively removing a portion of the top electrode by irradiating the top electrode with a laser beam. The method of claim 1, Forming the insulating layer, Forming a photoresist pattern on the base electrode; Anodizing the base electrode to form an insulating layer on a portion of the base electrode other than the photoresist pattern; Removing the photoresist pattern and second anodizing the base electrode to form a tunneling insulating layer thinner than the insulating layer in the center of the base electrode from which the photoresist pattern is removed. Method of manufacturing the device. The method of claim 2, Forming a first metal layer on the insulating layer; Forming a second metal layer on the first metal layer; Patterning the second metal layer such that a hole facing the tunneling insulating layer is formed vertically with the first metal layer interposed therebetween; And forming a top surface of the top electrode material on the substrate. A field emission display device having a base metal-insulating layer-top metal structure, The top metal is patterned by being selectively removed by a laser beam irradiated to the top metal.