KR20000002642A - Method of gate electrode formation of field emission display - Google Patents

Abstract

PURPOSE: A method of gate electrode formation is provided to prevent the induction of crack on the gate electrode by the electrode difference of the gate electrodes on the upper part of a cathode line. CONSTITUTION: A method of gate electrode formation of a field emission display comprises: forming a cathode electrode(13) onto a substrate(11) and an insulating layer(15) onto the whole surface and attaching the metal for a gate electrode onto the insulating layer; forming a hole to expose the cathode electrode by etching the metal for a gate electrode and the insulating layer and undercut toward bottom of a gate electrode(19).

Description

Gate electrode formation method of field emission device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a gate electrode of a field emission display (hereinafter referred to as a FED), and more particularly, to a gate electrode formed by a step of a gate electrode on an upper portion of a cathode line formed by intersection of a cathode electrode line and a gate electrode line. The present invention relates to a technology capable of improving the characteristics and reliability of devices by preventing cracks.

In general, a thin film type field emission device is a device that emits cold electrons by tunnel effect by applying a relatively low voltage, for example, a voltage of about several tens of volts by using a phenomenon in which an electric field is concentrated on a sharp part of a tip. The FED is attracting attention as a next generation display device because it has both the high definition of the CRT and the light and thin advantages of a liquid crystal display (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 part, a gate arranged on both sides of the cathode, and an anode spaced apart from the gate, each of which is a cathode and a caterpillar 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 emitted by an anode to which a positive voltage is applied. The phosphor is guided to emit the fluorescent material applied to the anode, and the gate controls the direction and amount of electrons.

1 is a cross-sectional view showing a gate electrode forming method of a field emission device according to the prior art.

First, the cathode electrode 33 is formed on the substrate 31.

Then, an insulating film 35 such as an oxide film is formed on the entire surface, and a metal for gate electrode is formed thereon.

Subsequently, an isotropic etching process using a tip mask (not shown) forms a hole exposing the cathode electrode 33 and simultaneously forms a gate electrode 39.

In addition, a sacrificial layer is formed on the gate electrode 39 by directional oblique deposition, and a tip 37 is formed on the cathode electrode 33 of the bottom of the hole by vertical deposition. The sacrificial layer is lifted off. By removing, a field emitter array (FEA) of the FED is formed.

At this time, the crack ⓐ is induced in the portion of the gate electrode 39 having a step due to the cathode electrode 33.

Ⓐ is a crack at a portion where the gate and the cathode intersect, and is more likely to occur according to the thickness of the cathode, and may be caused by stress when manufacturing a large-area display device.

In order to solve this problem, the gate electrode metal must be deposited by a high temperature thermal process or a subsequent heat treatment process must be performed at a high temperature. However, since the FED uses glass as a substrate, the thermal process at a high temperature is difficult.

As described above, in the method of forming a gate electrode of the field emission device according to the related art, a step is caused in the gate electrode due to the step difference between the cathode electrode line and the portion where the cathode electrode line and the gate electrode line intersect, thereby causing the There is a problem that the crack is caused in the stepped position, thereby deteriorating the characteristics and reliability of the FED.

Accordingly, the present invention is to solve the above problems, by forming an auxiliary pattern on the upper portion of the gate electrode caused cracks due to the step is made of a material such as the gate electrode metal to prevent degradation of the characteristics and reliability of the FED due to cracks It is an object of the present invention to provide a method for forming a gate electrode of a field emission device.

1 is a cross-sectional view showing a gate electrode forming method of the FED according to the prior art.

2A and 2B are cross-sectional views illustrating a method of forming a gate electrode of an FED according to an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

11,31 substrate 13,33 cathode electrode

15,35 insulating film 17,37 tip

19,37 gate electrode 21 photosensitive film pattern

23: auxiliary pattern

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

In the method for forming a gate electrode of the field emission device,

Forming an insulating film on the substrate on which the cathode electrode is formed;

Forming a gate electrode on the insulating layer and forming a gate electrode having a step on an upper portion of the portion intersecting the cathode electrode;

Forming a hole through which the tip is formed by etching the gate electrode and the insulating layer;

Forming a tip in contact with the cathode electrode through the hole;

Forming a photoresist pattern on the gate electrode to expose a portion having the step;

Forming an auxiliary pattern on the gate electrode by using the photoresist pattern as a mask;

And removing the photoresist pattern.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2A and 2B are cross-sectional views illustrating a gate electrode forming method of the field emission device according to the method of the present invention.

First, the cathode electrode 13 is formed on the substrate 11.

Then, an insulating film 15 is formed over the entire surface, and a metal for gate electrode is deposited to a certain thickness on the top.

In addition, a hole exposing the cathode electrode 13 is formed by etching the gate electrode metal and the insulating layer 15 by an isotropic etching process using a tip mask (not shown), and simultaneously forming the gate electrode 19. An undercut (not shown) is formed under the gate electrode 19.

In this case, the gate electrode 19 is formed to have a structure intersecting with the cathode electrode 13 to have a step on the upper side of the step between the cathode electrode 13 and the substrate 11. In addition, the gate electrode 19 is cracked due to the step difference.

Then, as in the process of FIG. 1, the tip 17 is formed inside the hole by using the directional gradient deposition method and the vertical deposition method.

Then, the photoresist layer pattern 21 is formed on the entire surface to expose the crack upper side formed by the step difference between the cathode electrode 13 and the substrate 11.

The auxiliary pattern 23 is formed on the gate electrode 19 using the photoresist pattern 21 as a mask, and is formed using a metal of Al, Ni, or Ag having the same properties as the gate electrode 19. As a result, the characteristics and the reliability of the gate electrode can be improved.

As described above, the gate electrode forming method of the FED according to the present invention has a characteristic of the gate electrode by forming an auxiliary pattern using a separate mask on the crack formed on the gate electrode due to the step difference between the cathode electrode and the substrate. By preventing the degradation, there is an effect that can improve the characteristics and reliability of the FED.

Claims (2)

In the method for forming a gate electrode of the field emission device, Forming an insulating film on the substrate on which the cathode electrode is formed; Forming a gate electrode on the insulating layer and forming a gate electrode having a step on an upper portion of the portion intersecting the cathode electrode; Forming a hole through which the tip is formed by etching the gate electrode and the insulating layer; Forming a tip in contact with the cathode electrode through the hole; Forming a photoresist pattern on the gate electrode to expose a portion having the step; Forming an auxiliary pattern on the gate electrode by using the photoresist pattern as a mask; A method of forming a gate electrode of a field emission device comprising the step of removing the photoresist pattern. The method of claim 1, The auxiliary pattern is a gate electrode forming method of a field emission device, characterized in that formed with a metal such as Al, Ni or Ag having the same characteristics as the gate electrode.