KR20000043854A - Method for forming gate hole of field emission display - Google Patents

Abstract

PURPOSE: A method for forming a gate hole of a field emission display is provided to increase a distance between a cathode metal and a gate metal for increasing a passage of a leakage current so that the insulation property is improved and the property and the reliability of the field emission display are improved. CONSTITUTION: A method for forming a gate hole of a field emission display, in which the leakage current property of the field emission display is improved, includes the steps of stacking an insulation layer(23) and a gate metal(25) on a substrate formed with a cathode metal(21), drying etching the gate metal and the insulation layer by using a mask forming gate holes, and forming a gate hole(29) of which surface area is increased by wet etching a side surface of the insulation layer by a predetermined thickness.

Description

Gate hole formation method of field emission device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a gate hole of a field emission display (hereinafter referred to as a FED), in particular, by increasing the distance between a cathode metal and a gate metal when forming an emitter tip, The present invention relates to a technique for increasing the surface distance between the cathode metal and the gate metal in order to prevent performance degradation of the device due to dielectric breakdown and leakage current between the metal and the gate metal.

In general, a thin film type field emission device is a device that emits cold electrons due to a tunnel effect by applying a relatively low voltage, for example, a voltage of about 5 to 10V by using a phenomenon in which an electric field is concentrated on a sharp part of a tip. The formed FED has attracted attention as a next generation display device because it has both the high definition of CRT and the light and thin type of liquid crystal display (hereinafter referred to as LCD).

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.

That is, in case of LCD, even if one unit pixel is defective, the whole product is treated badly. However, FED has a smaller number of unit pixels in one pixel group, so even if one or two unit pixels are defective, There is no problem in operation, and the yield of the whole product is improved.

In addition, FED has advantages such as simple structure, low power consumption, low unit cost, and suitable for portable display device.

Initially, the FED is exposed to the outside by a cavity, and is composed of a conical cathode having a sharp portion, a gate aligned on both sides of the cathode, and an anode spaced apart from the gate, each of which is a cathode and a gate of the CRT. And an anode.

In the FED, a voltage is applied to the anode, for example, a voltage of about 500 to 10 mA, and electrons are emitted by an electric field concentrated at the top of the cathode, and the emitted electrons are guided by an anode to which a positive voltage is applied. To emit the fluorescent material applied to the anode, and the gate controls the direction and amount of electrons.

Although not shown, the gate hole forming method of the field emission device according to the prior art will be described.

First, a cathode metal, an insulating film, and a gate metal are sequentially formed on a substrate (not shown). In this case, the insulating film is formed of a silicon oxide film.

A photoresist pattern is formed on the gate metal. In this case, the photoresist pattern is for forming a gate hole.

The gate metal is etched using the photoresist pattern as a mask, and the gate metal is formed by wet etching or dry etching the insulating layer, and then the photoresist pattern is removed.

Subsequently, a tip is formed on the cathode metal inside the gate hole.

Recently, the insulating film has been used to form an insulating film having a laminated structure having a different etching selectivity and to increase the distance between the cathode metal and the gate metal in an etching process using the etching selectivity difference.

However, there is a problem in that a separate thin film having different properties between the insulating film and the gate metal is additionally deposited, thereby degrading the interface property between the additional process and the thin film.

For reference, in general, the leakage current is caused by the flow of electric charges on the surface of the insulator rather than directly through the insulator. This flow of charge increases as the gate voltage increases, and this leakage current degrades the electron emission characteristics of the device, increases power consumption, and, in severe cases, pixel driving becomes impossible.

Accordingly, the present invention is to solve the above problems, the surface area of the insulating film formed between the cathode metal and the gate metal is increased without a separate deposition process, the leakage current is connected between the cathode metal and the gate metal to improve the insulating properties It is an object of the present invention to provide a method for forming a gate hole of the FED, which can improve the characteristics and reliability of the FED device by preventing the breakage phenomenon.

1A and 1B are cross-sectional views illustrating a gate hole forming method of an FED device according to a first embodiment of the present invention.

2A to 2C are cross-sectional views illustrating a gate hole forming method of an FED device according to a second embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

11,21 cathode metal 13,23 insulating film

15,25: Gate metal 17,29: Gate hole

27: under cut

Features of the gate hole forming method of the field emission device according to the present invention for achieving the above object,

In the gate hole forming method of the field emission device with improved leakage current characteristics,

Stacking an insulating film and a gate metal on the substrate on which the cathode metal is formed;

Dry etching the gate metal and the insulating layer using a mask for forming a gate hole;

A first feature is to form a gate hole having an increased surface area by etching the insulating film by a predetermined thickness.

In addition, the gate hole forming method of the field emission device according to the present invention to achieve the above object,

In the gate hole forming method of the field emission device with improved leakage current characteristics,

Stacking an insulating film and a gate metal on the substrate on which the cathode metal is formed;

An undercut is formed under the etched gate metal by wet etching the gate metal and an insulating layer having a predetermined thickness using a mask for forming a gate hole,

Dry etching the insulating layer until the cathode metal is exposed to form a gate hole,

A second feature is to include a step of side etching the insulating film to increase the surface area between the gate metal and the cathode metal.

Hereinafter, a method of forming a gate hole of a field emission device according to the present invention will be described in detail with reference to the accompanying drawings.

1A and 1B are cross-sectional views illustrating a gate hole forming method of a field emission device according to the method of the present invention.

First, the cathode metal 11 is formed on the glass substrate (not shown). In addition, an insulating layer 13 and a gate metal 15 are deposited on the cathode metal 11.

Then, the gate metal 15 is patterned. In this case, the gate metal 15 pattern is formed by an etching process using a photoresist pattern formed by exposing and developing the mask using a mask capable of applying a photoresist film on the gate metal 15 and forming a gate hole. .

Thereafter, the insulating layer 13 is dry etched to form a gate hole 17 exposing the cathode metal 11. (FIG. 1A)

The photoresist layer pattern is removed, and the insulating layer 13 is laterally etched by a wet etching process using a difference in etching selectivity between the gate metal 15, the cathode metal 11, and the insulating layer 13.

In this case, the side etching process is performed so that about 10 to 30% of the total thickness of the insulating film 13 is etched. (FIG. 1B)

2A to 2C are cross-sectional views illustrating a gate hole forming method of an FED according to a second embodiment of the present invention.

First, a cathode metal 21 is formed on a glass substrate (not shown). In addition, an insulating layer 23 and a gate metal 25 are deposited on the cathode metal 21.

Then, the gate metal 25 is patterned. In this case, the gate metal 25 pattern is formed by an etching process using a photoresist pattern formed by exposure and development using a mask that can apply a photoresist film on the gate metal 25 and form a gate hole. .

Next, the insulating layer 23 is etched to a predetermined thickness by a wet etching process using an etching selectivity difference from the gate metal 25 pattern, and an undercut 27 is formed under the gate metal 25 pattern.

At this time, the wet etching process is to etch about 20 to 50% of the deposition thickness of the insulating film (23). (FIG. 2A)

Thereafter, the insulating film 23 is dry-etched using the photoresist pattern as a mask to form a gate hole 29 exposing the cathode metal 21. (FIG. 2B)

In addition, the insulating layer 23 is etched by 10 to 30% using the difference in the etching selectivity of the gate metal 25, the cathode metal 21, and the insulating film 23, so that the cathode metal 21 and the gate metal ( 25) further increase the surface distance of the liver; (FIG. 2C)

As described above, the gate hole forming method of the FED according to the present invention can increase the distance between the cathode metal and the gate metal to increase the passage of the leakage current, thereby improving the insulation characteristics of the device and thereby There is an effect that can improve the characteristics and reliability.

Claims (5)

In the gate hole forming method of the field emission device with improved leakage current characteristics, Stacking an insulating film and a gate metal on the substrate on which the cathode metal is formed; Dry etching the gate metal and the insulating layer using a mask for forming a gate hole; Forming a gate hole having an increased surface area by etching the insulating layer by a predetermined thickness. The method of claim 1, And the side etching process is performed by a wet method by 10 to 30% of the thickness of the insulating film. In the gate hole forming method of the field emission device with improved leakage current characteristics, Stacking an insulating film and a gate metal on the substrate on which the cathode metal is formed; An undercut is formed under the etched gate metal by wet etching the gate metal and an insulating layer having a predetermined thickness using a mask for forming a gate hole, Dry etching the insulating layer until the cathode metal is exposed to form a gate hole, And etching the insulating film side by side to increase a surface area between the gate metal and the cathode metal. The method of claim 3, wherein The wet etching process may etch by 10 to 50% of the thickness of the insulating film. The method of claim 3, wherein The side etching process is performed by a wet method to etch by 10 to 30% of the thickness of the insulating film deposition method.