KR20070029959A - Manufacturing method of carbon nanotube fed using neutral beam - Google Patents

Abstract

A manufacturing method of a carbon nanotube FED using a neutral beam is provided to enhance reproducibility and uniformity of a carbon nanotube emitter by exposing a carbon nanotube from a surface of a carbon nanotube paste. A carbon nanotube paste(307) to be used as an emitter is formed on a cathode electrode. A baking process is performed to bake the carbon nanotube paste. A binder element is removed from a surface of the carbon nanotube paste by irradiating neutral beam(308) on the baked carbon nanotube paste. A carbon nanotube is exposed to the surface of the carbon nanotube paste by removing the binder element. A method for forming the cathode electrode includes a process for forming cathode metal layer(303) on a transparent substrate, a process for forming a cathode line on the cathode metal layer, a process for depositing a gate insulating layer(305) on the cathode electrode, a process for forming a gate metal layer(306) on the gate insulating layer, and a process for forming a gate hole on the gate metal layer.

Description

Manufacturing method of carbon field emission display device using neutral beam {Manufacturing method of carbon nanotube FED using neutral beam}

1 is a schematic diagram of a general tripolar CNT field emission display device constructed of CNTs as emitters;

2A to 2B are views showing the process of the tripolar device for a CNT field emission display device related to the surface treatment of the CNT paste used as an emitter, which is a feature of the invention;

3A to 3B show a process of a bipolar device for a CNT field emission display device related to the surface treatment of a CNT paste used as an emitter, which is a feature of the present invention;

4A to 4F are views showing a process of forming a tripolar cathode electrode which is one embodiment of a field emission display device;

5A to 5C are views illustrating a process of forming a CNT paste according to the embodiment;

6 is a schematic diagram showing the configuration of a neutral beam generator for generating a neutral beam in connection with the CNT paste surface treatment according to the present invention.

7 is a SEM photograph after firing the CNT paste printed on the cathode;

8 is a view showing a SEM photograph after the surface treatment by the Adhesive Taping method of the conventional CNT paste surface treatment method,

9 is a view showing an SEM photograph after the surface treatment by Ar + plasma in the conventional surface treatment method of CNT paste;

FIG. 10 is a SEM photograph after surface treatment with Ar + ion beam in the conventional surface treatment method of CNT paste. FIG.

The present invention relates to a method for manufacturing a CNT field emission display device using an emitter as a carbon nanotube in a field emission array (FEA), and more particularly, effective field emission and excellent reproducibility of a CNT paste used as an emitter. And it relates to a method for manufacturing a CNT field emission display device comprising a new surface treatment for uniformity.

Recently, a new field of nanotechnology has emerged as a result of research showing new physical phenomena and improved material properties in the nanometer-sized micro-area, and this nanotechnology is a science technology that can lead 21C in the future. It has emerged as a future technology in the fields of electronic information communication, medicine, materials, manufacturing process, environment and energy.

In the field of nanotechnology, FED (Field Emission Display) technology is recently attracting much attention in the field of image display. It is also called a field emission display in a manner that generates light by accelerating collision of electrons emitted by an electric field.

It consists of a cathode panel and a cathode panel. The electrons emitted from the cathode plate are irradiated onto the phosphor of the anode plate to display an image. Its operation is similar to that of conventional CRT (cathode ray tube) and its flat plate is called next generation flat CRT.

However, while the CRT displays the image by scanning electrons emitted from one electron gun, the FED uses the electrons emitted from numerous electron guns of very small size to excite each phosphor in front and emit light. The display is different.

Like the CRT, the FED operates by cathode ray emission, and thus has a high luminous efficiency and a wide viewing angle. Small size, light weight, fast operation speed and low manufacturing cost. On the other hand, it is urgent to develop an efficient low voltage phosphor because the driving voltage is higher than that of LCD.

In recent years, carbon nanotubes (CNTs) have recently been able to realize new material properties.

Carbon nanotubes are not easily deformed mechanically, and have many advantages such as chemical stability and negative electron affinity (NEA) characteristics, and as a result, their application as electronic devices is increasing.

In particular, the negative electron affinity (NEA) characteristics are the main reason for considering CNT, which is a kind of FED, as a very suitable material for field emission devices, and the field emission characteristics from CNTs have a somewhat poor vacuum environment. It is also known to have stable emission characteristics. Such characteristics may be a great advantage when applied to an actual device, considering that deterioration of the degree of vacuum is inevitable to some extent after the actual packaging process.

In order to overcome this problem, the conventional field emission device (FED) structure, which directly forms a CNT emitter in a gate hole, is used to form a CNT emitter uniformly with symmetry in the gate hole. It is very difficult to make a reproducible CNT emitter-gate structure.

In order to overcome the problems of the CNT emitter formation method by the direct growth method described above, CNT is formed into a paste form and pushed into the gate hole by screen printing or rolling and doctor blade methods. A method of forming the rotor is used. In particular, the CNT paste may be mixed with a photosensitive material to leave CNTs only in the gate holes by a photolithography method.

In this case, if a negative photoresist is used as the photosensitive material, the backside exposure is performed on the opposite side of the CNT-coated glass surface to selectively leave only the exposed CNT paste in the gate hole. It is possible to form a reproducible gate-emitter structure.

FIG. 1 shows a schematic diagram of a tripolar CNT field emission display device constructed using the CNT as an emitter. The cathode metal film 30 is formed on a transparent substrate, and an insulating film and an gate metal film 20 are formed on the upper layer to apply a voltage to induce a field emission from the meter 50 to the CNT.

As a result, due to the voltage difference between the gate electrode 20 and the anode 10 coated with fluorescent particles, the emitted electrons collide with the fluorescent particles to finally emit light.

However, one of the important problems in the emitter manufacturing method using the CNT paste is the surface treatment method.

The CNT paste is a material in which a certain amount of CNT particles are mixed in the binder component. When firing after printing, the CNT particles are buried in the binder and cannot emit electrons. The key is to selectively remove some of the binder from the surface of the paste so that the CNT particles themselves come out of the surface to release the electrons.

This process of revealing the CNT particles themselves out of the surface is called surface treatment, which is an adhesive taping method in which conventional adhesive tape is adhered to the surface of a paste at a constant pressure and then peeled off. There is this

In addition, a method of ionizing an inert gas such as argon (Ar) or nitrogen (N ₂ ) to accelerate the ion beam to a voltage of several hundred volts to expose the CNT paste, and to plasma the gas of argon or nitrogen. And a method of surface-treating CNT paste in a plasma state, and a method of surface-treating by irradiating a laser beam.

However, the most widely used adhesive taping method is effective in terms of surface treatment, but foreign substances such as adhesives may remain, especially when a CNT paste emitter is formed below the gate electrode height in the gate hole such as a three-pole structure. There is a drawback of not being properly surface treated.

In the plasma method, not only the binder component constituting the CNT paste is removed but also the effect of selectively removing the binder by CNT itself is severely reacted with ions and radicals in the plasma to be removed.

In addition, the ion beam method improves the selective removal of the binder than the plasma method, but also, there is a fear that CNTs may be rapidly erased by the chemical reaction between the Ar + ions and the CNTs. The method also has a disadvantage in that the throughput is slow.

The present invention has been made to solve the above problems, and proposes a method for manufacturing a CNT field emission display device including a new surface treatment for effective field emission and excellent reproducibility and uniformity of the CNT paste used as an emitter, CNT To simplify the process of the emitter array, to provide a CNT field emission display device to form a CNT emitter excellent in reproducibility and uniformity.

The present invention for achieving the above object relates to a method for manufacturing a CNT field emission display device, comprising the steps of forming a CNT paste for use as an emitter on the cathode, firing the formed CNT paste, and And a surface treatment step of irradiating a CNT paste with a neutral beam to remove the binder component on the paste surface, thereby exposing the CNT itself onto the surface.

The forming of the cathode may include forming a cathode metal film by depositing a metal film on one surface of the transparent substrate, forming a cathode line by photolithography on the formed cathode metal film, and forming a gate insulating film on the cathode on which the line is formed. It is preferable to form the three-pole display device, which includes depositing, depositing a gate metal film on the gate insulating film, and forming a gate hole by photolithography on the gate metal film.

Furthermore, the forming of the cathode electrode may be performed by forming a cathode metal film on a transparent substrate to form a bipolar display device.

In addition, the forming of the CNT paste may include printing a negative photosensitive CNT paste, and developing only the exposed CNT paste by exposing UV ultraviolet rays to the cathode electrode on which the CNT paste is formed. It is preferable to include.

Further, the forming of the CNT paste may be applied by screen printing, doctor blade, or spin coating.

On the other hand, the CNT paste may be a metal powder is mixed, preferably the CNT paste may be characterized in that the frit is mixed.

In the firing step, the CNT emitter paste may be calcined at a temperature of 300 ° C. or higher, and the neutral beam may be an inert gas as an ion source, or an oxygen gas as an ion source. . The acceleration energy of the neutral beam is preferably irradiated in the range of 100 eV to 1000 eV.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to a preferred embodiment of the manufacturing method of the CNT field emission display device according to the present invention.

2A to 2B show a first embodiment showing a process of a tripolar device for a CNT field emission display device related to the surface treatment of a CNT paste used as an emitter, which is a feature of the present invention.

As shown in FIG. 2A, a transparent conductive film 302 and a cathode electrode film 303 are sequentially deposited on the substrate 301 to form a tripolar cathode electrode composed of an insulating film 305 and a gate electrode film 306. The CNT paste 307 for use as an emitter is applied on the cathode and the CNT paste 307 is fired.

FIG. 2B also shows the firing of a neutral beam of the fired CNT paste 307 to remove the binder in the CNT paste 307 so that the CNT 307 'is well visible on the surface. to be.

The CNT paste is formed by mixing a powder, a binder, and a solvent in a predetermined ratio. When the applied paste 307 is fired, the CNT particles 307 'are buried in the binder. Can not be released. Thus, the neutral beam 308 is irradiated for more effective CNT particle exposure.

3A to 3B show a second embodiment showing a process of a bipolar device for a CNT field emission display device related to the surface treatment of a CNT paste used as an emitter, which is a feature of the present invention.

As shown in FIG. 3A, the conductive film 402 and the cathode metal film 403 are sequentially deposited on the transparent substrate 401, and then the CNT paste 407 for use as an emitter is applied to the upper layer. 407) is shown.

FIG. 3B shows a process that causes the fired CNT paste 407 to irradiate the neutral beam 408 to effectively expose the CNT 407 'to the surface.

Meanwhile, FIGS. 4A to 4F show details of a process of forming a tripolar cathode electrode.

4A illustrates a transparent substrate 101, and FIG. 4B is a cross-sectional view of the cathode conductive film 201 and the cathode metal electrode film 103 deposited on the transparent substrate 102.

4C shows a photoresist 104 is applied to form a cathode line, a pattern is formed on the photoresist 104 by a conventional photolithography method, and then used as a mask for etching. It is sectional drawing of the board | substrate of the state in which the cathode electrode which has a double film | membrane structure was formed by etching each of the metal film 103 and the conductive film 102 by a step).

4D is a cross-sectional view in which a gate insulating film is deposited on the transparent substrate 101 on which the cathode electrode is formed, and the insulating film 105 is electrically shorted when a voltage is applied between the cathode electrode film and the gate metal film 106 to be formed later. This is to prevent.

4E is a cross-sectional view of a substrate on which a metal film 106 to be used as a gate electrode is deposited on the gate insulating film 103. Such gate electrodes can be used with any material that provides sufficient conductivity.

4F is a cross-sectional view of the substrate through which the through hole 109 of the gate hole in which the CNT emitter is to be formed is made. Photolithography method by applying photoresist

The photoresist pattern is formed and the gate metal film 106, the gate insulating film 105, and the cathode metal film 103 are sequentially etched by an etching process.

In this process, the gate metal film 106, the gate insulating film 105, and the cathode metal film 104 are continuously etched using one gate hole mask so that the centers of the gate electrode holes and the cathode electrode holes coincide with each other. In other words, self-alignment is possible.

5A to 5C illustrate an embodiment of forming the CNT paste, and FIG. 5A is a cross-sectional view when the photosensitive CNT paste 207 is applied to the entire surface of the substrate on which the cathode electrode is formed. This CNT paste 207 can be applied by screen printing, doctor blade method or spin coating method.

FIG. 5B illustrates a cross-sectional view of the substrate in a state of exposing using ultraviolet (UV) through a black mask 210 on the opposite side of the surface to which the CNT paste 207 is applied. At this time, the incident light is transmitted through the mask 210 and only the exposed CNT paste 207 'remains, and only the unexposed CNT paste is removed by the developer.

The reason why the light is passed through the mask is because light is transmitted by the transparent conductive film 201 and the transparent conductive film 202, and the rest of the light is blocked by the cathode metal film 203 and the black mask. to be. This is because the photosensitive material of the photosensitive CNT paste is not affected by the developer during exposure by using a negative type.

5C is a cross-sectional view of the substrate on which the CNT emitter 207 'is formed after the development is completed, and it can be seen that the CNT emitter 207' and the gate hole are symmetrically formed by self-alignment at regular intervals.

In addition, the coated CNT paste 207 may be formed by mixing a metal powder at a predetermined ratio. This is to increase the conductivity to facilitate the field emission, and the frit may be mixed in a certain ratio to increase the bonding force.

Firing of the CNT paste 207 may be performed at a temperature of 300 ° C. or more in order to facilitate the surface treatment of the paste.

6 is a schematic diagram showing the configuration of a neutral beam generator for generating a neutral beam. The CNT itself is effectively exposed to the CNT paste surface by irradiating a neutral beam with the substrate 500 as a cathode electrode substrate coated with CNT paste, which is a target object for surface treatment.

In the neutral beam generation, when the low energy ion beam collides with a reflector such as a metal, the neutral beam is generated to generate a neutral beam. Therefore, by extracting and accelerating an ion beam having a certain polarity from the ion source 501, reflecting the accelerated ion beam 501 to a reflector to convert the ion beam into a neutral beam, and then features on the path of the neutral beam The substrate 500 is positioned, and the neutral beam is irradiated to the CNT paste to perform surface treatment.

The neutral beam may be an ion source 501 as an inert gas having high reactivity for improving yield, and further, an oxygen gas as an ion source for effective removal of the CNT binder. have.

In addition, the acceleration energy of the neutral beam may be irradiated in the range of 100 eV to 1000 eV. This is for effective binder removal in relation to the binding energy of the binder in the CNT paste.

Referring to the results of the surface treatment of the CNT paste related to the manufacturing method of the CNT field emission display device as described above compared with the conventional method is as follows.

7 is a SEM photograph after firing the CNT paste printed on the cathode electrode. As can be seen from the photo, it can be seen that a large amount of CNT paste binder is formed.

8 is a SEM photograph after surface treatment by an adhesive taping method for removing the binder. Although CNT itself is exposed to many surfaces, it is difficult to apply to a specific display device.

In addition, Figure 9 is an SEM image after the surface treatment by the Ar plasma, it can be seen that a large amount of binders in the CNT paste is removed, but the CNT itself is not removed by the reaction with the plasma ions can not be effective surface treatment. .

In addition, FIG. 10 shows an SEM image after surface treatment with an Ar + ion beam, but CNTs are rapidly erased due to chemical reaction between CNTs and Ar + ions, and thus are not effective for selective removal of a binder.

Therefore, if the neutral beam is irradiated to the surface of the CNT paste used as the emitter proposed in the present invention, it is possible to solve the difficulties in the implementation of the adhesive taping method, and the CNT particles generated from the surface treatment method by ion beam or plasma. It can solve problems such as damage of CNT itself due to reactivity.

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

As described above, when the CNT field emission display device manufacturing method using the neutral beam according to the present invention is provided, the CNT Emi having excellent reproducibility and uniformity can be easily and effectively revealed on the surface of the CNT paste used as an emitter. It is possible to manufacture the array, and in particular, it can be effectively applied to the manufacture of the field emission display device having a three-pole structure can improve the large panel characteristics.

Claims (11)

In the field emission display device manufacturing method, Forming a CNT paste for use as an emitter on the cathode electrode; Firing the formed CNT paste; And, CNT field emission display device comprising a surface treatment step to expose the CNT itself on the surface by irradiating a neutral beam to the fired CNT paste to remove the binder component on the paste surface Manufacturing method. The method of claim 1, The forming of the cathode may include forming a cathode metal film by depositing a metal film on one surface of the transparent substrate; Forming a cathode line by photolithography on the formed cathode metal film; Depositing a gate insulating film on the cathode on which the line is formed; Depositing a gate metal film on the gate insulating film; And, And forming a gate hole by photolithography on the gate metal film to form a tripolar display device. The method of claim 1, The forming of the cathode electrode is a method of manufacturing a CNT field emission display device, characterized in that to form a cathode metal film on a transparent substrate to form a bipolar display device. The method of claim 1, The forming of the CNT paste may include printing a negative photosensitive CNT paste; A method of manufacturing a CNT field emission display device, comprising: forming only the CNT paste of an exposed backside portion by developing by exposing UV ultraviolet rays to the backside of the cathode on which the CNT paste is formed. The method according to any one of claims 1 and 2, Forming the CNT paste is a method of manufacturing a CNT field emission display device characterized in that the coating by a screen printing (screen printing), doctor blade method or spin coating method. The method according to any one of claims 1 and 2, The CNT paste is a CNT field emission display device manufacturing method characterized in that the metal powder is mixed. The method according to any one of claims 1 and 2, The CNT paste is a CNT field emission display device manufacturing method characterized in that the frit is mixed. The method of claim 1, The firing step is a CNT field emission display device manufacturing method characterized in that the firing the CNT emitter paste at a temperature of 300 ℃ or more. The method according to any one of claims 1 and 2, The neutral beam is a CNT field emission display device, characterized in that the inert gas as an ion source (source). The method according to any one of claims 1 and 2, The neutral beam is a CNT field emission display device characterized in that the oxygen gas (O ₂ ) as an ion source (source). The method according to any one of claims 1 and 2, The acceleration energy of the neutral beam is irradiated in the range of 100eV to 1000eV CNT field emission display device manufacturing method.

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