KR20020031817A - A field emission display and manufacturing method for it - Google Patents

Abstract

PURPOSE: An FED(Field Emission Display) and a method for fabricating the same are provided to prevent a cross-talk phenomenon by forming a CNT(Carbon Nano Tube) on a cathode electrode part. CONSTITUTION: An anode electrode(32) is formed on a rear substrate(30). The rear substrate(30) is formed by a material such as a silicon wafer or a glass. An insulating layer(34) having an emitter hole(40) is formed on the anode electrode(32). A fluorescent material(42) is formed on the anode electrode(32) exposed by the emitter hole(40). A catalytic metal layer(36) and a cathode electrode layer(38) are formed sequentially on the insulating layer(34). A CNT(44) is formed on an edge portion of the emitter hole(40) of the catalytic metal layer(36). The insulating layer(34) is formed with an oxide layer or a nitride layer. The catalytic metal layer(36) is formed by a metal such as Co or Ni or Fe. The cathode electrode layer(38) is formed by a low resistance metal layer such as Cr. A front substrate(50) is installed on the rear substrate(30).

Description

Field emission display and manufacturing method for it {A field emission display and manufacturing method for it}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display (hereinafter referred to as a FED) and a method of manufacturing the same. In particular, a cathode electrode may be formed on the rear substrate in a back emission FED in which a phosphor and an anode are positioned on the rear substrate. When a carbon nanotube (hereinafter referred to as CNT) is formed on the edge of the catalytic metal layer to prevent crosstalk, the FED and its manufacturing method can improve process yield and reliability of device operation. will be.

The thin film type field emission device is a device that emits cold electrons by tunnel effect by applying a relatively low voltage by using a phenomenon in which the electric field is concentrated on the sharp part of the tip. The liquid crystal display (hereinafter referred to as LCD) has all the advantages of the light and thin type, attracting attention as a next generation display device. In particular, the FED can not only manufacture the thin and thin, but also solve the problems of process yield, manufacturing cost, and enlargement, which are crucial disadvantages of the LCD.

In other words, if a single unit pixel is defective, the entire product will be treated as defective. However, FED has a smaller number of emitter tips formed in one pixel group. There is no abnormality in the operation of the group, which improves the overall product yield.

In addition, the FED has a simple structure compared to the LCD, low power consumption, low cost, there are some advantages suitable for the portable display device.

Initially, the FED is exposed to the outside by a cavity, and has a conical emitter tip having a sharp portion, a gate arranged on both sides of the emitter to control the amount of current, and a fluorescent plate spaced apart from the gate at a predetermined interval. It consists of an attached anode electrode, each of which corresponds to a cathode, a grid and an anode of the CRT.

In the FED, when a predetermined voltage, for example, a voltage of about 500 to 10 mA is applied, electrons are emitted by an electric field concentrated at the tip of the emitter tip, and the emitted electrons are applied to an anode to which a positive voltage is applied. Guides the light emitting fluorescent material applied to the anode, and the gate controls the direction and amount of electrons.

However, in the early FED having the conical cathode as described above, some of the emitted electrons are induced to the gate, so that the gate current flows to control the electrons, and cations formed by colliding with the electrons between the cathode and the anode, Since the device is destroyed by collision, it is necessary to maintain the inside of the device in a high vacuum state in order to prevent such a high vacuum maintenance is difficult, there is a problem such as difficult to uniform production of sharp cone-shaped cathode.

In addition, since a high voltage is required at the anode and the gate electrode, application to a portable display device is difficult.

In order to solve these problems, a thin film type field emission device has been proposed, in which three conductive thin films insulated from each other are sequentially installed on a substrate conductor, and a part of the three conductive thin films is formed to protrude through the cavity. Proposed structure of the anode by installing an external electrode on the upper side.

The thin film type field emission device having such a structure applies a negative voltage to a cathode, which is a conductive thin film located at the center, and emits electrons by applying an alternating voltage to gate conductive thin films located on both sides of the cathode, and is strong to the substrate conductor. A negative voltage is applied to cause electrons emitted from the cathode to strike the anode, which is an external electrode.

As the thin film type field emission display device according to the related art, a device using silicon as a substrate and an electrode is attracting attention due to its easy manufacturing method and material selection. Such a silicon device uses a cathode tip made of polycrystalline silicon on a silicon substrate. Forming a gate insulated from the cathode by forming a wet etching method using a nitride film pattern as an etching mask, applying an oxide film and a metal film to the entire surface, and removing the nitride film pattern by a lift off method. Used.

In the method of manufacturing the field emission display device by the lift-off process using the silicon material according to the prior art as described above, the short circuit between the tip and the gate is likely to occur, the tip is damaged, and the process yield and the uniformity are poor. There is a problem such as lowering the reliability of device operation.

In order to solve the above problem, the diamond or pseudo-diamond (DLC) material is characterized by chemical stability, low electron affinity, high resistance to ions, etc. Applying a coating method on the top of the tip, or using a CNT as an emitter with excellent field emission characteristics is being studied.

1 is a cross-sectional view of a FED according to the prior art, and is an example showing only the unit pixels of the FED using CNT as an emitter.

First, the cathode electrode 12 is formed on the back substrate 10 made of silicon, glass, or the like, and the catalyst metal layer 14 and the CNT 16, which are emitters, are formed on the cathode electrode 12. The anode electrode 22 and the phosphor 24 formed on the front substrate 20 are formed thereon.

CNTs used in the FED according to the prior art have excellent field emission characteristics mainly appear only at the edge portion, so that a separate gate electrode is formed to spread at a considerable angle even when the current direction is adjusted so that the color spreads to the side pixels. There is a problem in that the torque is generated and the image quality is degraded and, in severe cases, poorly processed, the process yield falls.

The present invention is to solve the above problems, an object of the present invention is to form a CNT in the cathode electrode portion in the back-emitting FED to prevent cross-talk and increase the field emission efficiency to enable low voltage drive process yield And to provide a FED and a method of manufacturing the same that can improve the reliability of device operation.

1 is a cross-sectional view of a FED using CNTs according to the prior art.

2 is a cross-sectional view for explaining the FED according to the present invention.

Figure 3a to 3e is a manufacturing process of the FED according to the present invention.

<Description of Symbols for Main Parts of Drawings>

10,30: back substrate 12,38: cathode electrode

14,36 catalyst metal layer 16,44 CNT

20,50: front substrate 22,32: anode electrode

24, 42 phosphor 34: insulating film

40 emitter hole 48 cathode metal layer

52: photosensitive film pattern

The characteristics of the field emission display device according to the present invention to achieve the above object,

In the back-emitting field emission display device having an anode, a rear substrate on which a phosphor and a cathode are formed, and a front substrate coupled to an upper portion thereof,

An anode electrode formed on the rear substrate,

An insulating film formed sequentially on the structure and having an emitter hole for exposing the anode electrode;

A phosphor formed on the anode electrode exposed by the emitter hole,

A catalyst metal layer and a cathode electrode which are sequentially formed on the insulating layer and whose edge portions are exposed to the emitter hole;

CNT formed in the emitter hole side edge portion of the catalyst metal layer,

The front substrate is coupled to the rear substrate to transmit the light prevented from the phosphor.

In addition, another feature of the FED is that the back substrate is formed of a silicon wafer or a glass material, the insulating film is formed of an oxide film or a nitride film, the catalyst metal layer is formed of Co, Ni or Fe, the cathode metal layer is formed of Cr The front substrate is made of glass, quartz or plastic,

Features of the FED manufacturing method according to the present invention,

Forming an anode on the back substrate;

Sequentially forming an insulating film, a catalyst metal layer, and a cathode metal layer on the entire surface of the structure;

Forming a photoresist pattern for forming emitter holes on the cathode metal layer;

Sequentially etching the cathode metal layer exposed by the photosensitive film pattern from the cathode metal layer to the insulating film to form an emitter hole exposing the anode electrode;

Applying a phosphor on the exposed anode electrode and the photosensitive film pattern;

Removing the photoresist pattern and the phosphor thereon;

And growing a CNT in an edge portion of the catalyst metal layer on the emitter hole side.

Hereinafter, a FED and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a cross-sectional view of the FED according to the present invention, an example of a back-emitting FED, showing only the unit pixel.

First, an anode electrode 32 is formed on a back substrate 30 such as silicon or glass, and an insulating film 34 having an emitter hole 40 is formed on the anode electrode 32. The phosphor 42 is formed on the anode electrode 32 exposed by the emitter hole 4, and the catalytic metal layer 36 on which the edge portion is exposed on the insulating film 34 toward the emitter hole 40. ) And the cathode electrode 38 are sequentially formed, and the CNT 44 is formed at the edge portion of the emitter hole 40 side of the catalyst metal layer 36. The back substrate 30 may be formed of a material such as silicon wafer or glass, the insulating film 34 may be formed of an oxide film or a nitride film, and the catalyst metal layer 36 may be formed of a metal that is easy to grow CNT. Co, Ni, Fe, or the like, and the cathode metal layer 48 is formed of a low resistance metal such as Cr.

In addition, the front substrate 50 made of transparent glass, quartz or plastic is installed on the rear substrate 30 so that the light emitted from the phosphor 42 of the rear substrate 30 passes to form a screen. .

In the FED, when voltage is applied to the anode electrode 32 and the cathode electrode 38, electrons are emitted from the CNT 44 to strike the phosphor 42 on the anode electrode 32, and the generated light Radiated to the front substrate 50 constitutes a screen.

3A to 3E are diagrams illustrating a manufacturing process of the FED according to the present invention, showing only a rear substrate.

First, the anode electrode 32 is formed on the rear substrate 30, and the insulating film 34, the catalyst metal layer 36, and the cathode metal layer 48 are sequentially formed on the entire upper substrate. The back substrate 30 may be formed of a material such as silicon wafer or glass, the insulating film 34 may be formed of an oxide film or a nitride film, and the catalyst metal layer 36 may be formed of a metal that is easy to grow CNT. Co, Ni or Fe or the like is formed to a thickness of about 1 to 100 μm, and the cathode metal layer 48 is formed of a low resistance metal such as Cr or the like. (See FIG. 3A).

Next, a photoresist pattern 52 is formed on the cathode metal layer 48 to form an emitter hole, and the insulating layer 34 is formed on the cathode metal layer 48 exposed by the photoresist pattern 52. The emitter holes 40 are sequentially formed to form an emitter hole 40 exposing the anode electrode 32. Here, the cathode metal layer 48 becomes the cathode electrode 38 by an etching process, and the etching process of the insulating film 34 is an isotropic etching process to form the emitter hole 40 in a jar shape. Said etching can also be performed anisotropically. (See FIG. 3C).

Then, when the phosphor 42 is coated on the surface, the phosphor 42 is coated on the exposed anode electrode 32 and the photoresist pattern 52, (see FIG. 3D). And the phosphor 42 on the upper side thereof, and the CNT 44 is grown on the edge portion of the catalyst metal layer 36 on the emitter hole 40 side to complete the back substrate 30 of the FED. In this case, the CNTs 44 are generally formed by chemical vapor deposition (hereinafter, referred to as CVD). (See Figure 3E).

Thereafter, although not shown, the transparent front substrate is sealed and the sealed interior is kept under vacuum to seal the completed FED.

As described above, the FED and the method of manufacturing the same according to the present invention form a CNT on the edge portion of the catalyst metal layer on the emitter hole side, which exposes the anode electrode and the fluorescent layer on the upper side of the FED, so that the field is emitted. Crosstalk due to discharge scattering of CNT is prevented at the source, and the front substrate does not have to be a separate process, and thus, the front substrate can be made of glass or plastic, which can reduce manufacturing costs. Since it is formed in a ring shape, it is possible to effectively use the high-efficiency field emission performance of the CNTs, thereby improving process yield and reliability of device operation.

Claims (8)

In the back-emitting field emission display device having an anode, a rear substrate on which a phosphor and a cathode are formed, and a front substrate coupled to an upper portion thereof, An anode electrode formed on the rear substrate, An insulating film formed sequentially on the structure and having an emitter hole for exposing the anode electrode; A phosphor formed on the anode electrode exposed by the emitter hole, A catalyst metal layer and a cathode electrode which are sequentially formed on the insulating layer and whose edge portions are exposed to the emitter hole; CNT formed in the emitter hole side edge portion of the catalyst metal layer, And a front substrate coupled to the rear substrate to transmit light that is prevented from the phosphor. The method of claim 1, The back substrate is a field emission display device, characterized in that formed of a silicon wafer or glass material. The method of claim 1, And the insulating film is formed of an oxide film or a nitride film. The method of claim 1, The catalytic metal layer is a field emission display device, characterized in that the metal is easy to CNT growth is formed of one metal arbitrarily selected from the group consisting of Co, Ni and Fe. The method of claim 1, And the cathode metal layer is formed of Cr. The method of claim 1, The front substrate is a field emission display device, characterized in that formed of one material arbitrarily selected from the group consisting of glass, quartz and plastic. Forming an anode on the back substrate; Sequentially forming an insulating film, a catalyst metal layer, and a cathode metal layer on the entire surface of the structure; Forming a photoresist pattern for forming an emitter hole on the cathode metal layer; Sequentially etching the cathode metal layer exposed by the photosensitive film pattern from the cathode metal layer to the insulating film to form an emitter hole exposing the anode electrode; Applying a phosphor on the exposed anode electrode and the photosensitive film pattern; Removing the photoresist pattern and the phosphor thereon; And growing a CNT in an edge portion of the catalyst metal layer on the emitter hole side. The method of claim 7, wherein And manufacturing the CNTs by CVD.