KR100434533B1 - Method for manufacturing field emitter array - Google Patents

Abstract

According to the present invention, the cathode is formed by a spin method, and a plurality of cathodes on a stripe are formed side by side on the surface of the rear substrate, and an insulator layer having holes is formed on the cathode, and a metal gate is formed on the insulator layer. A method of manufacturing a field emitter array having a sharp first tip formed in a conical shape on an exposed surface of the cathode, the opening having an opening corresponding to the hole of (A), comprising: (a) an electron beam deposition method while rotating the substrate; Depositing a metal film layer at the tip of the tip; (B) forming a second tip covering the first tip by electron beam deposition while rotating the substrate; (C) etching and removing the metal film byproduct layer and the second tip byproduct layer on the metal film byproduct layer; And (d) etching the second tip to form a tip having a plurality of sharp parts.

Therefore, by forming a tip for the field emission having a plurality of sharp parts to increase the current emission per single tip to reduce the number of gate holes, while preventing the leakage of current, the damage of the device due to the generation of heat, The advantage is that the distribution is dense.

Description

Method for manufacturing field emitter array

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a field emission display device, and more particularly, to a method for manufacturing a field emitter array having a compact electric field distribution by forming a tip for electron emission having a plurality of sharp parts to increase current emission per single tip. .

Field emitter arrays are widely used as electron emission units of field emission displays, which are currently attracting attention as next-generation flat panel display devices.

Such a field emitter array emits electrons by a strong electric field formed around it. At this time, the current density due to the emission of electrons is proportional to the intensity of the electric field formed around the field emitter, which is influenced by the geometry of the field emitter.

The field emitter array, which is typically used as an electron emitting portion of a field emission display, is manufactured in the form of tips having a spire shape with the tip of the element emitting electrons.

1 is a schematic cross-sectional view showing a field emitter array manufactured by a conventional spin method.

As shown in FIG. 1, a spindt-type field emitter array, which is widely used for field emission display devices, has a plurality of cathodes 12 formed side by side in a stripe shape on a glass substrate 11. , A conical micro tip 13 is formed at the bottom of the hole 14a, that is, at the surface of the exposed cathode 12.

The insulator layer 14 formed to enclose the micro-tips 13 and the insulator layer 14 to have an opening 15a corresponding to the hole 14a to enable electric field emission on top of the micro-tips 13. Is provided on the gate 15.

A method of manufacturing a spint field emitter array having such a configuration is as follows.

In the spin-type field emitter array manufacturing method, as shown in FIG. 2A, first, cathodes 12 are formed in a stripe shape on a glass substrate 11, and an insulator layer 14 and a gate layer are formed thereon. (15 ') is laminated sequentially.

Next, in a photolithography process, as shown in FIG. 2B, a photoresist mask 16 is formed on the gate layer 15 ′ and etched to form a gate 15 having an opening 15a.

Next, as shown in FIG. 2C, the photoresist mask 16 is removed, and the insulator layer 14 is etched using the gate 15 as a mask to form holes 14a in the insulator 14. do.

Next, as shown in FIG. 2D, a partition layer 17 is deposited on the gate 15, and as shown in FIG. 2E, the hole 12 is exposed while rotating the substrate 11. The tip 13 is formed by shooting an electron-beam inclined to the portion 14a) by electron beam deposition.

Next, by etching and removing the partition layer 17, the micro tip forming material 13a on the gate 15 is also removed.

In this way, a spin field field emitter array as shown in FIG. 1 is completed.

However, in general, field emitter arrays need to form 20 to 30 million gate holes, and if a leakage current is generated through these holes, the voltage between the gate electrode and the cathode is reduced to 80 due to the leakage current of the display device. In order to maintain ˜90V, a current of several tens of kΩ should be applied.

This may cause a problem in that the glass substrate on which the field emitter array is formed is broken by generating Joule heat in proportion to the square of the current intensity to generate heat stress in the display device.

In order to improve the above problems, the manufacturing method of the field emitter array according to the present invention is formed to have a plurality of sharp parts in the shape of the tip to reduce the number of gate holes to prevent stress due to heat, and the electric field distribution is dense Its purpose is to provide a method of manufacturing a field emitter array.

1 is a schematic vertical cross-sectional view showing a field emitter manufactured by a conventional spin method,

2A to 2E are vertical cross-sectional views of respective processes for describing the manufacturing process of FIG. 1,

3 to 5 are vertical cross-sectional views for each process for explaining a method of manufacturing a field emitter array according to the present invention.

<Explanation of symbols for the main parts of the drawings>

11,21 ... substrate 12,22 ... cathode

13 ... Tip 13a ... Tip Form

14,24 ... insulator layer 15,25 ... gate

16 ... mask 17 ... divided layer

23 ... Tip 27 ... Metal Byproduct Layer

28.Metal film layer 29 ... 2nd tip

29a ... 2nd tip byproduct layer

In order to achieve the above object, the manufacturing method of the field emitter array according to the present invention is formed by the spin method, and a plurality of cathodes on the stripe are formed in parallel on the surface of the rear substrate, and holes are formed on the cathodes. An insulator layer is formed, wherein a metal gate is formed on the insulator layer to have an opening corresponding to a hole in the insulator layer, and the field emitter array has a sharp first tip formed in a conical shape on the exposed surface of the cathode. A manufacturing method comprising the steps of: (a) depositing a metal layer on the tip of the tip by electron beam deposition while rotating the substrate; (B) forming a second tip covering the first tip by electron beam deposition while rotating the substrate; (C) etching and removing the metal film byproduct layer and the second tip byproduct layer on the metal film byproduct layer; And (d) etching the second tip to form a tip having a plurality of sharp parts.

The height of the first tip is greater than the height of the lower end of the gate, and in the step (b), the metal film layer is formed by inclining the electron beam at an angle of 15 to 30 degrees, and in the step (d), the second tip is formed. It is preferable to remove by etching by the wet etching method.

The height of the second tip is 5,000 to 15,000 1, the first and second tips are made of any one of molybdenum to tungsten, the metal film layer is preferably made of aluminum.

According to the present invention, by forming the shape of the tip to have a plurality of sharp parts to reduce the number of holes, to prevent stress due to Joule heat generated by the unique device leakage when the number of holes is large, the electric field distribution is Its feature is that it provides a method of making a dense field emitter array.

These features will be described in detail with reference to the accompanying drawings, a method of manufacturing a field emitter array according to the present invention.

3 to 5 are vertical cross-sectional views for each process for explaining a method of manufacturing a field emitter array according to the present invention.

First, as shown in FIG. 1 shown above, a field emitter array manufactured by a conventional spin method is provided.

The field emitter array manufactured by the spindt method has a plurality of cathodes 12 formed side by side in a stripe shape on the glass substrate 11, and an insulator layer having holes 14a formed on the cathode 12. 14, a metal gate 15 is formed thereon so as to have an opening 15a corresponding to the hole 14a of the insulator layer 14, and the bottom of the hole 14a, that is, the exposed cathode ( On the surface of 12) is formed a first tip 13 of conical shape made of molybdenum (Mo) to tungsten (W).

In this case, the height of the first tip 13 should be 300 nm higher than the height of the upper end of the gate, and the minimum height should be about the lower end of the gate 15 formed on the insulator layer 14. 14a) Adjust the size. The reason for this is to allow the metal film layer 28 to be described later to be easily deposited on the tip of the first tip 13.

Next, as shown in FIG. 3, the cathodes 22 formed in parallel on the glass substrate 21 on the glass substrate 21 by the conventional spin method and the bottom of the hole 24a, that is, the exposed cathode While rotating the glass substrate 21 on which the first tip 13 of the conical shape is formed on the surface of 22, the electron beam deposition method on the gate 25, that is, the electron beam is inclined at an angle of about 15 to 30 °, is inclined. When the metal film layer 28 made of aluminum (Al) is deposited on the upper end of the first tip 13, the metal film by-product layer 27 surrounds the gates 25 in a gentle shape on the gate 25. do.

Here, the metal film byproduct layer 27 serves as a partition layer for removing the second tip byproduct layer 29a to be described later.

Next, as shown in FIG. 4, the metal film layer 28 includes the second tip 29 made of molybdenum (Mo) to tungsten (W) by electron beam deposition while rotating the glass substrate 21. It is formed on the front surface of the formed first tip (13).

Here, the height of the second tip 29 is adjusted to about 5,000 to 15,000Å according to the size of the hole 24a so as to easily adjust the height of the outer crater of the tip 23 having a plurality of sharp parts to be described later. . In addition, due to the electron beam deposition by the rotation of the glass substrate 21, the second tip byproduct layer 29a of molybdenum may be smoothly formed on the metal film byproduct layer 27 on the gate 25. The metal film byproduct layers 27 are enclosed.

Finally, as shown in Figure 5, as a step of forming a tip 23 having a plurality of sharp parts according to the present invention, the metal film by-product layer 27 and the second tip by-product layer 29a as described above And the metal film layer 28 are removed by performing a wet etching process using a chemical solution, and the upper end of the second tip 29 and the metal film layer 28 are simultaneously removed. 23).

The field emitter array having the tips 23 having a plurality of sharp parts formed as described above has an advantage of reducing the number of holes 14a of the field emitter array by increasing the amount of current discharge per single tip.

That is, by reducing the number of holes 14a, unlike the conventional method, the voltage between the gate 25 and the cathode 22, which is required due to leakage current generated through a large number of holes, is maintained at a normal driving voltage of 80 to 90V. No additional dozens of currents need to be applied to prevent thermal stress on the panel due to Joule heat generation. Thereby, there is no possibility that the glass substrate in which the field emitter array is formed is broken by the thermal stress as mentioned above.

Here, the current emission is accelerated and collided toward the phosphor in which electrons are released from the tip of the field emitter array by the constant voltage across the gate 25 and the stronger constant voltage is applied. According to Fowler-Nordheim's theory, the current density of the emitted current is proportional to the square of the intensity of the electric field.

Therefore, the strength of the electric field and the current density with respect to the electric field are closely related to the shape of the tip for discharging the current.

That is, the tip 23 having a plurality of sharp parts increases the amount of current discharge per single tip, thereby densifying the distribution of the discharge current, thereby improving panel characteristics due to uniformity of current density, and reducing the number of holes 14a. Leakage current can be prevented. In addition, the process for forming the tip 23 having a plurality of sharp parts is also simple, making it easy to manufacture a field emitter array.

As described above, the method of manufacturing the field emitter array according to the present invention forms a tip for field emission with a plurality of sharp parts to increase the current emission per single tip to reduce the number of gate holes, thereby reducing leakage of current. At the same time, there is an advantage in that the damage of the device due to the generation of heat is prevented and the electric field distribution is compact.

Claims (7)

In the spin method, a plurality of cathodes on a stripe are formed in parallel on a surface of a back substrate, an insulator layer having holes formed on the cathode is formed, and a metal gate corresponding to the holes of the insulator layer is formed on the insulator layer. A method of manufacturing a field emitter array, the method comprising: forming a field emitter array having a sharp first tip formed conically on an exposed surface of the cathode; (A) depositing a metal layer on the tip of the tip by electron beam deposition while rotating the substrate; (B) forming a second tip covering the first tip by electron beam deposition while rotating the substrate; (C) etching and removing the metal film byproduct layer and the second tip byproduct layer on the metal film byproduct layer; And (D) etching the second tip to form a tip having a plurality of sharp parts; manufacturing method of a field emitter array comprising a. The method of claim 1, And the height of the first tip is greater than or equal to the height of the lower end of the gate. The method of claim 1, In the step (b), The metal film layer is a method of manufacturing a field emitter array, characterized in that formed by inclining the electron beam at an angle of 15 to 30 degrees. The method of claim 1, In the step (d), And removing the second tip by etching by wet etching. The method of claim 1, The height of the second tip is 5,000 to 15,000Å, characterized in that the manufacturing method of the field emitter array. The method of claim 1, And the first and second tips are made of one of molybdenum to tungsten. The method of claim 1, The metal film layer is a method of manufacturing a field emitter array, characterized in that made of aluminum.