KR100539737B1 - Field emission device of manufacturing method - Google Patents

Abstract

The present invention does not form through-holes of a complicated process in manufacturing a field emission device having a counter electrode undergate structure using carbon nanotubes as a field emission emitter, and uses a simplified manufacturing process to reduce process time and improve yield. The present invention relates to a method of manufacturing a field emission device capable of increasing a height, comprising: forming a conductive layer on a glass substrate, forming a gate line through a pattern, and screen printing through the pattern on the structure of the gate line. Forming an insulating layer to expose a portion, forming a cathode electrode and a gate electrode connected to the exposed gate line on the same plane above the insulating layer, and forming a carbon nanotube on the formed cathode electrode Including the steps to reduce the number of steps, can simplify the manufacturing process Easier to manufacture, there is an effect that can increase the yield by reducing the process time.

Description

FIELD EMISSION DEVICE OF MANUFACTURING METHOD}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a field emission device, and in particular, in the manufacture of a field emission device having a counter electrode undergate structure using carbon nanotubes as a field emission emitter, it does not form a through hole of a complicated process, The present invention relates to a method for manufacturing a field emission device capable of reducing process time and increasing yield using a manufacturing process.

 Due to the rapid development of information and communication technology and the demand for the visualization of diversified information, the demand for electronic displays is increasing and the required display appearance is also diversified. For example, in an environment where mobility is emphasized such as a portable information device, a display having a small weight, volume, and power consumption is required, and when used as an information transmission medium for the public, display characteristics of a large viewing angle are required.

In addition, in order to satisfy such demands, electronic displays require conditions such as large size, low price, high performance, high definition, thinness, and light weight, so that light and thin that can replace the existing CRT are required to satisfy these requirements. There is an urgent need for the development of flat panel display devices.

Recently, as the needs of various display devices have been applied to display fields, devices using field emission have been actively developed for thin film displays that can provide high resolution while reducing size and power consumption.

The field emission device is attracting attention as a next-generation information communication flat panel display that overcomes all the disadvantages of flat panel displays (LCD, PDP, VFD, etc.) currently being developed or produced. The field emission device has a simple electrode structure, high-speed operation using the same principle as the CRT, and has the advantages of display such as infinite color, infinite gray scale, high brightness, and high video rate. .

Field emission devices utilize quantum mechanical tunneling which causes electrons to exit the vacuum from the metal or conductor when a high field is applied on the metal or conductor surface (emitter) in the vacuum. At this time, the device exhibits the current-voltage characteristic according to the Fowler-Nordheim law. The field emission device is composed of an emitter, which emits electrons and emits electrons collided with each other, an anode portion for supporting light emission, a spacer for supporting the upper and lower plates, and a sealing portion for maintaining a vacuum tightness.

Recently, the importance of the field emission device using the carbon nanotubes (CNT) because of the mechanically strong, chemically stable and excellent electron emission characteristics at a relatively low vacuum degree has been recognized. Since such carbon nanotubes have a small diameter (about 1.0 to several tens of nanometers), the field enhancement factor is considerably superior to the conventional microtip type spin emission field emission tips, and thus the emission threshold is low. Since it can be made in a turn-on field (about 1 to 5 [V / μm]), there is an advantage of reducing power loss and production cost. Referring to the conventional field emission device and a method of manufacturing the same in detail with reference to the accompanying drawings as follows.

1 is a cross-sectional view of an example of a three-electrode structure of a field emission device using a conventional carbon nanotube. As shown, the resistive layer 12, the insulating layer 14, and the gate electrode 15 are sequentially formed on the silicon substrate 11, and the gate electrode 15 and the insulating layer 14 are formed by photolithography. A portion is etched to form a hole, and then a catalyst transition metal layer 13 is formed on the resistive layer 12 at the bottom of the hole through evaporation, and the entire silicon substrate 11 is 600 to 900 [deg.] C. The carbon nanotubes 16 may be selectively heated only on the catalyst transition metal layer 13 through a thermal chemical vapor deposition method or a plasma chemical vapor deposition method using a hydrocarbon gas by heating to a temperature range of a degree. To form.

In this case, since the carbon nanotubes 16 are selectively formed only on the catalyst transition metal layer 13, the larger the area of the catalyst transition metal layer 13, the larger the area of the carbon nanotubes 16. As such, when the area of the carbon nanotubes 16 increases, the electric field applied through the gate electrode 15 is not concentrated, so that the beam of the emitted electrons is spread and the electron emission region is not even. Only the electron emission is likely to occur locally, and due to an asymmetric electric field distribution, the leakage current to the gate electrode 15 has many problems.

In order to solve the above problems, structures of the carbon nanotube field emission device having the gate electrode positioned at the same or lower position than the cathode electrode have been proposed.

2 is a cross-sectional view of an example of a field emission device having an under gate structure using a conventional carbon nanotube. As shown, the electric field causing the electron emission is applied to the gate electrode 21 under the carbon nanotube 24. The gate electrode 21 is formed on the glass substrate 20, and the insulating layer 22 and the cathode electrode 23 are sequentially formed on the glass substrate 20, and then the carbon nanotube mixed slurry is formed on the cathode electrode 23. Is applied by screen printing or the like to form a carbon nanotube 24 through a series of binder removal processes.

However, the field emission device of the undergate structure has a disadvantage in that the turn-on voltage is relatively high because the gate electrode 21 is located below the cathode electrode 23, and is abnormal due to the high pressure of the upper anode electrode (not shown) formed thereafter. There is a problem that light emission may appear.

FIG. 3 is a plan view and a cross-sectional view of a counter electrode undergate structure field emission device using a conventional carbon nanotube, and unlike FIG. 2, through holes are formed in the upper insulating layer 32 of the lower gate line 31. Thus, the gate electrode 34 is formed on the same plane as the cathode electrode 33. As shown in the drawing, the gate electrode 34 and the cathode electrode 33 are formed on the same plane, and the turn-on voltage at which the electron emission occurs in the carbon nanotube 35 is low, and thus the driving voltage can be lowered. . This structure insulates a portion of the gate line 31 by exposing and etching processes so that the gate line 31 passing under the cathode electrode 33 is coplanar with the cathode electrode 33. A through hole must be formed in layer 32 and the part filled with metal.

4A to 4D are cross-sectional views showing a conventional method of manufacturing a count electrode undergate structure field emission device, and a complicated through hole forming process is required as shown.

First, as shown in FIG. 4A, the conductive layer is formed and patterned on the glass substrate 30 to form the gate line 31. The gate line 31 serves as a common line connecting the gate electrode 34.

Next, as shown in FIG. 4B, after forming the insulating layer 32 on the entire upper surface of the formed structure, the insulating layer 32 is etched to expose a portion of the gate line 31 so as to pass through holes (via). ).

Next, as shown in FIG. 4C, a conductive layer is formed on the structure to fill the through hole, and a conductive layer is formed on the upper portion of the structure to be patterned to connect the gate line 31 to the through hole. The gate electrode 34 and the cathode electrode 33 are formed.

Finally, as shown in FIG. 4D, the carbon nanotubes 35 are formed at the edges of the cathode electrode 33 by screen printing.

As described above, in the method of manufacturing a field emission device having a count electrode undergate structure using a carbon nanotube as described above, a gate electrode connected to the gate line is formed on the same plane as the cathode electrode by using a through hole. However, the size of the through hole is typically determined by the thickness of the insulating layer, the material and the etching method, and when forming the thick film dielectric layer, it is difficult to form the through hole having a fine size.

In addition, the formation of the through hole is one of high process difficulty processes, which greatly affects the overall yield.

In the field emission device of the count electrode undergate structure using the conventional carbon nanotube, the process of forming the through hole and then filling the metal with the metal is indispensable to configure the gate electrode on the same plane as the cathode electrode. There was a problem that the yield is lowered by the through hole forming process having a high difficulty.

Therefore, in view of the above problem, the present invention forms an insulating layer using a screen printing method having a pattern exposing a part of the gate line, and the cathode electrode and the part or the whole of the exposed gate line and the upper part of the insulating layer; It is an object of the present invention to provide a method of manufacturing a field emission device capable of simplifying a manufacturing process by reducing the number of processes by forming a gate electrode to be connected, and increasing a yield by reducing a process time.

The field emission device of the present invention for achieving the above object comprises a gate line formed on the glass substrate; An insulating layer formed by a pattern on the gate line to expose a portion of the gate line; A cathode electrode having a carbon nanotube formed on the insulating layer and a gate electrode connected to the exposed gate line and formed on the same plane as the cathode electrode may be included.

The gate electrode is connected to some or all of the exposed gate line.

The field emission device manufacturing method of the present invention for achieving the above object comprises the steps of forming a conductive layer on a glass substrate, and forming a gate line through a pattern; Forming an insulating layer on the structure to expose a portion of the gate line by screen printing through a pattern; Forming a gate electrode connected to the cathode electrode and the exposed gate line on the same plane above the insulating layer; Forming a carbon nanotube on the formed cathode electrode is characterized in that it comprises.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the field emission device of the present invention having the above characteristics and a manufacturing method thereof will be described with reference to the accompanying drawings.

5 is a plan view and a cross-sectional view of an embodiment of a field emission device of a count electrode undergate structure according to the present invention. As shown in the drawing, the gate electrode 54 and the cathode electrode 53 are formed on the same plane, and the gate line 51 passing below the cathode electrode 53 is coplanar with the cathode electrode 53. The insulating layer 52 is formed by using a screen printing method using a pattern so as to be located at a position, and then a gate electrode 54 is formed by coating a portion of the gate line 51 exposed by the pattern with metal. That is, the connection between the gate electrode 54 and the gate line 51 is not used through the conventional through hole (via), but instead using the insulating layer 52 having a patterned structure.

Then, the manufacturing method of the field emission device of the present invention having such a structure will be described with reference to Figs. 6A to 6D.

6A to 6D are cross-sectional views illustrating a method of manufacturing a count electrode undergate structure field emission device according to an embodiment of the present invention. As shown in FIG. 6A, a conductive layer is formed and patterned on a glass substrate 50 to form a gate line ( 51). The gate line 51 serves as a common line connecting the gate electrode 54.

Next, as shown in FIG. 6B, the insulating layer 52 is formed through screen printing with a pattern so as to expose a part of the gate line 51 on the upper surface of the formed structure. When the insulating layer 52 is formed using the pattern, the process is simplified because an additional process for forming a through hole is not required as in the prior art.

Next, as shown in FIG. 6C, a conductive layer is formed on the same plane above the structure and then patterned to form a gate electrode 54 and a cathode electrode connected to a part of the exposed gate line 51. 53). In general, when the same height of the cathode electrode 53 and the gate electrode 54 is the same, the conductive layer may be formed on the insulating layer 52 and then patterned. On the other hand, when the height of the gate electrode 54 is different, the cathode electrode 53 is formed first, and the gate electrode 54 is formed independently, or the cathode electrode 53 and the gate electrode 54 having the same thickness are formed. After that, a process for further increasing the gate electrode 54 may be performed. In this case, the distance between the formed cathode electrode 53 and the gate electrode 54 can be kept constant at all times. Even if the cathode electrode 53 and the gate electrode 54 are separately formed, the distance can be aligned at a desired position.

Finally, as shown in FIG. 6D, a method of printing, lift-off, photolithography, electrophoresis, etc., of the carbon nanotubes 55 at the edges of the cathode electrode 53 is provided. To form.

The field emission device of the present invention formed through such a process does not require a complicated process of forming a through hole, and forms a patterned insulating layer to expose a portion of the gate line after forming a gate line, and forms a gate electrode without an additional process. There is an advantage that can be formed.

7 and 8 show yet another embodiment of the present invention. As shown, to form an electrically stable connection between the gate line 51 and the gate electrode 54, a patterned portion of the insulating layer 52, i.e., a portion of the gate line 51 It can be formed by covering all the exposed portions (Fig. 7) or by covering only half (Fig. 8).

The present invention can reduce the number of processes to shorten the manufacturing process due to the patterned insulating layer structure that exposes a portion of the gate line to the connection of the gate electrode and the gate line, it is easy to manufacture compared to the existing structure It has the advantage of reducing time and increasing yield.

In addition, although there is a limit to reducing the distance between the patterns of the insulating layer formed by the printing method using a pattern, such restrictions are reduced as the area becomes larger, which may be a structure suitable for a large area flat panel display device, and has a stripe shape. Forming an insulating layer pattern of the can have a relatively small line width has the advantage of implementing a high resolution.

As described in detail above, the present invention forms an insulating layer using a screen printing method having a pattern exposing a part of the gate line, and connects the cathode electrode and part or all of the exposed gate line on the insulating layer. By forming the gate electrode to be reduced, the number of processes can be simplified to simplify the manufacturing process, and the production is easy, and the process time can be shortened to increase the yield.

1 is a cross-sectional view showing an example of a three-electrode field emission device using a conventional carbon nanotube.

Figure 2 is a cross-sectional view showing an example of the field emission device of the undergate structure using a conventional carbon nanotube.

3 is a plan view and a cross-sectional view showing an example of a field emission device having a counter electrode undergate structure using a conventional carbon nanotube.

4A to 4D are sectional views showing the manufacturing process of the field emission device of FIG.

Fig. 5 is a plan view and a sectional view showing an example of the field emission device of the counter electrode undergate structure of the present invention.

6A to 6D are sectional views showing the manufacturing process of the field emission device of the present invention.

7 and 8 are cross-sectional views showing yet another structure of the present invention.

** Description of the symbols for the main parts of the drawings **

50: glass substrate 51: gate line

52: insulating layer 53: cathode electrode

54: gate electrode 55: carbon nanotube

Claims (3)

delete delete Forming a conductive layer on the glass substrate, and forming a gate line through a pattern of the conductive layer; Forming an insulating layer on the structure to expose a portion of the gate line by screen printing through a pattern; Forming a gate electrode connected to a cathode electrode and a part or all of the exposed gate line on the same plane above the insulating layer; And forming a carbon nanotube on the formed cathode electrode.