KR100257571B1 - Method for producing a silicide field emitter array using double-metal layer of fed - Google Patents

Abstract

PURPOSE: A method for forming silicide field emitter array using dual metal layer is provided to make FEA that pure silicide is formed with by using secondary deposited metal as protection layer when forming silicide after removing deposition material of the top of silicon tip with CMP process. CONSTITUTION: An oxidation film disk of a designated size is formed on the top of silicon substrate(11). A peaked shape silicon tip is formed by making a heat oxidation silicon surface exposed after making an isotropic etching lower silicon substrate(11) considering above oxidation film disk as etching mask. Gate oxidation film(17) is made an incline deposition on the top of whole structure using electron beam depositor. Gate metal is made an incline deposition in a designated angle on the top of whole structure. Material of the top of gate metal is removed by CMP process. Tip is protruded by removing selectively only oxidation film around silicon tip. The first metal(23) is deposited first on the top of whole structure by sputtering, and then the second metal(25) is deposited on the top of the first metal(23) as protection layer of the first metal(23). It is removed residual metal not to be reacted between the second metal(25) deposited secondary and the first metal deposited first.

Description

Method for forming silicide field emitter array using double metal layer

The present invention relates to a method of forming a silicide field emitter array (hereinafter referred to as FEA) using a double metal layer, and in particular, suicide of a second deposited metal by depositing a double metal on an exposed silicon tip. The present invention relates to a silicide FEA formation method using a double metal layer capable of producing a pure silicide-formed FEA by using as a protective layer during formation.

In general, a field emitter display (FED) uses a phenomenon in which an electric field is concentrated on a sharp part of a tip, and thus a relatively low voltage, for example, a voltage of about 5 to 10V, is applied by a tunnel effect. As a device for emitting cold electrons, an FED formed using the same 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 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, for example, 5 to 10 V, is applied to the anode to emit electrons by an electric field concentrated at the top of the cathode, and the emitted electrons are delivered by the 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.

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 difficult to maintain the inside of the device in a high vacuum state in order to prevent this.

In addition, it is not only difficult to make a uniform conical cathode when manufacturing FEA, but also the durability is weak, which may easily damage the tip of the tip, and cross-talk between pixels due to the spreading of the emitted electron beam. There is a problem such as this occurs.

Therefore, the present invention is to solve the above problems, an object of the present invention is to remove the deposits on the silicon tip by a CMP process, and then to deposit the second metal on the exposed silicon tip to deposit the second metal deposited The present invention provides a method for forming silicide FEA using a double metal layer that can produce FEA having pure silicide formed by using a protective layer when forming silicide.

1A-1H are cross-sectional views illustrating a process step for fabricating a silicide field emitter array using a double metal layer in accordance with the techniques of the present invention.

<Explanation of symbols for main parts of drawing>

11 silicon substrate 13 oxide disk

15: thermal oxide film 17: gate oxide film

19: gate metal film 21: silicon tip

23: first metal 25: second metal

27: silicide

Method for forming silicide FEA using a double metal layer of the present invention for achieving the above object,

Forming an oxide disk having a predetermined size on the silicon substrate;

Isotropically etching the lower silicon substrate using the oxide film as an etch mask, and thermally oxidizing the exposed silicon surface to form a pointed silicon tip;

Obliquely depositing the gate oxide film at a predetermined angle using an electron-beam evaporator on the entire structure;

Gradient depositing the gate forming metal on the entire structure at an angle;

Removing material on the gate metal by a CMP process;

Selectively removing only an oxide film around the silicon tip to protrude the tip;

Depositing a first metal on top of the entire structure by sputtering, and depositing a second metal on top of the first metal with a protective layer of the first metal;

And removing the unreacted residual metal in the second deposited second metal and the first deposited first metal.

Hereinafter, an embodiment of a silicide FEA forming method using a double metal layer according to the present invention will be described in detail with reference to the accompanying drawings.

First, a transition metal is used to prepare FEA using general silicide formation, and the heat treatment process is performed in a nitrogen atmosphere.

However, in the heat treatment process, a compound of metal and nitrogen in terms of nitrogen and metal crab, for example, TiN is formed in the case of Ti silicide.

Accordingly, by forming another transition metal on the Ti metal to obtain TiSi ₂ , and removing the metal, it is possible to form FEA in which silicide is formed in a pure state.

1A to 1H are cross-sectional views illustrating silicide FEA manufacturing process steps using a double metal layer according to the method of the present invention.

First, an oxide film disk 13 having a diameter of 1 to 2 μm is formed on a silicon substrate 11 by a photo lithography process (see FIG. 1A).

After the isotropic etching of the lower silicon substrate 11 using the oxide film disk 130 as an etching mask, the exposed silicon surface is thermally oxidized to form a pointed silicon tip (see FIG. 1B).

Next, the gate oxide film 17 is obliquely deposited at a predetermined angle, for example, at an angle of 30 to 45 ° using an electron-beam evaporator on the entire structure, and then heat treatment is performed to improve the oxide film quality (see FIG. 1C).

Thereafter, the gate metal 19 is inclinedly deposited at 40 to 45 degrees on the whole structure (see FIG. 1D).

The material on top of the gate metal 19 is then removed using a chemical mechanical polishing (hereinafter referred to as CMP) process (see FIG. 1E).

Next, only the oxide films 15 and 17 around the silicon tip 21 are selectively removed to protrude the tip 210 (see FIG. 1F).

Thereafter, the first metal 23 is first deposited on the entire structure by sputtering, and the first metal 23 is deposited using a metal having a low work function and excellent thermal stability, and a protective metal of the first deposited first metal 23. The second metal 25 is deposited on the first metal 23, and then heat-treated (see FIG. 1G).

Next, the unreacted residual metal in the second deposited second metal 25 and the first deposited first metal 23 is removed (see FIG. 1H).

Pure silicide may be formed on the silicon tip surface by forming the double metal layer as described above.

As described above, after removing the deposit on the silicon tip by the CMP process according to the method of the present invention, by depositing a double metal on top of the exposed silicon tip, the second deposited metal is used as a protective layer during silicide formation This makes it possible to produce FEA with pure silicide.

Claims (5)

Forming an oxide disk having a predetermined size on the silicon substrate; Isotropically etching the lower silicon substrate using the oxide film as an etch mask, and thermally oxidizing the exposed silicon surface to form a pointed silicon tip; Obliquely depositing the gate oxide film at a predetermined angle using an electron-beam evaporator on the entire structure; Gradient depositing the gate metal at an angle on the entire structure; Removing material on the gate metal by a CMP process; Selectively removing only an oxide film around the silicon tip to protrude the tip; Depositing a first metal on top of the entire structure by sputtering, and depositing a second metal on top of the first metal with a protective layer of the first metal; And removing unreacted residual metal from the second deposited second metal and the first deposited first metal. The method of claim 1, The oxide film disk is a silicide FEA forming method using a double metal layer, characterized in that the oxide disk disk having a diameter of 1 ~ 2㎛. The method of claim 1, The method of forming a silicide FEA using a double metal layer, wherein the inclination deposition angle of the gate oxide layer is 30 to 45 °. The method of claim 1, The method for forming silicide FEA using a double metal layer, wherein the inclination deposition angle of the gate metal is 40 to 45 °. The method of claim 1, The method of forming silicide FEA using a double metal layer, wherein the first metal is a metal having a low work function and excellent thermal stability.

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