KR100641104B1 - Surface conduction electron emitting device and manufacturing method thereof - Google Patents

Abstract

A surface conduction electron emitting device and a manufacturing method thereof are provided to enhance accuracy of a position of a foaming gap and reduce a characteristic difference between devices by forming the foaming gap only within a conductive layer having a reduced thickness. A surface conduction electron emitting device includes a substrate(302), a conductive layer, and a foaming gap. A pair of electrodes(301) are formed on the substrate. The conductive layer is connected with the electrodes between the electrodes and is formed with two or more layers(303,304). The conductive layer includes a removal region(305) which is formed by removing partially an area including the foaming gap in a thickness direction. The foaming gap is formed on the removal region.

Description

Surface conduction electron-emitting device and its manufacturing method {SURFACE CONDUCTION ELECTRON EMITTING DEVICE AND MANUFACTURING METHOD THEREOF}

1 is a plan view and a cross-sectional view showing a general structure of a conventional field emission device.

Figure 2 is a cross-sectional view showing the principle of operation of the conventional surface conduction field emission device.

3 is a cross-sectional view and a plan view of an embodiment of the present invention.

Figure 4 is a cross-sectional view showing a conductive film forming process of an embodiment of the present invention.

Figure 5 is a cross-sectional view showing a process of forming a conductive film of another embodiment of the present invention.

Figure 6 is a micrograph of the structure formed using an embodiment of the present invention.

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

101: substrate 102: electrode

103: conductive film 104: active layer

201: top substrate 202: phosphor

203: anode electrode 301: electrode

302: substrate 303, 304: conductive film

305: etching region 401: substrate

402: electrode 403: first conductive film

404: second conductive film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface conduction electron-emitting device and a method of manufacturing the same. In particular, a conductive film of a region in which a forming gap is to be formed through an etching process is formed so as to form a forming gap irregularly formed in an energizing forming process only within a designated position and region. The present invention relates to a surface conduction electron-emitting device and a method of manufacturing the same, in which a forming gap is formed only in a corresponding region during energizing forming by reducing thickness.

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 flat panel display for overcoming all the disadvantages of flat panel displays (LCD, PDP, VFD, etc.) currently being developed or produced. The field emission device display has a simple electrode structure, high-speed operation based on the same principle as the CRT, and has the advantages that the display has such as infinite color, infinite gray scale, high luminance, and high video rate. have.

Conventional field emission devices are composed of a conventional spindt method using silicon or molybdenum tip shapes, a metal-insulator-metal (MIM) method in which an insulating layer is sandwiched between two metals, and nanosilicon instead of an insulator. BSD (Ballistic) and CNT-FED using carbon nanotubes as emitters.

Recently, a surface conduction electron emission (SCE) method is known as a different method of electron emission, and a surface conduction electron emission display, also known as a surface conduction electron emission display (SED), has been developed using the same. It was also demonstrated.

The SCE method was originally discovered in SnO ₂ thin films by M. Elison in 1965 (Radio Eng. Electron Phys. 1965), and applied current in parallel to the surface of the thin film formed into small areas on the substrate. It uses the phenomenon that electron emission occurs by shedding. This phenomenon was later referred to as Au thin film (G. Ditter, Thin Solid Films' Vol. 9, p.317,1972), In ₂ O ₃ / SnO ₂ thin film (M. Hartwell, IEEE Trans.ED Conf, p.519, 1975 ), Or carbon films (Hisashi Araki, Vol. 26, No. 1, p. 22, 1983).

FIG. 1 is a plan view and a cross-sectional view of a typical SCE device, in which cathodes and gate electrodes are formed on a substrate 101 with electrodes 102 patterned with metal (Pt, Ag) or transparent electrodes (ITO) at regular intervals. A conductive film 103 made of a metal such as Au or an oxide such as PdO is formed between the two electrodes 102.

An energization process called electronic forming is performed on the conductive film 103 to form an electron emission region (forming gap). In the energization forming process, a constant DC voltage pulse is applied to the two electrodes 102 so that a current flows in the conductive film 103 having a larger resistance than the electrode 102, thereby providing a conductive film 103 having a large resistance. This local destruction, deformation or alteration creates an electrically high state of resistance. Structurally, very narrow (~ tens of nanometers) cracks are formed on the conductive film. Electrically, high resistance (~ 1 MΩ) regions are formed.

When a pulsed voltage is applied across the two electrodes 102 of the SCE element, current flows from the cathode electrode (cathode) toward the gate electrode (anode). The surface conduction electron emission phenomenon refers to a phenomenon in which electrons are released as current flows through the conductive films on the two electrodes, and the emission current Ie emitted at this time is very small compared to the conduction current If flowing directly along the conductive film. The efficiency of the device is determined by the ratio of the emission current to the conduction current. Therefore, in order to have good efficiency, the emission current must be increased and the conduction current must be minimized. In order to minimize the conduction current, the resistance on the conductive film must be increased, and in order to increase the emission current, a sharp shape must be configured to apply a high electric field on the conductive film. For this reason, when conduction forming is performed, gaps of a certain interval are formed on the conductive film, so that a gap having a very high resistance is formed, thereby minimizing conduction current, and electric field is concentrated at the edge of the gap. Therefore, electrons can be easily emitted from the corners, thereby increasing the emission current. For this reason, the forming process is an essential part of device fabrication and a key process that determines the characteristics of SCE devices.

As described above, the forming process uses a method of generating a deformation of the conductive film by Joule heat by applying a pulse voltage to both electrodes on the substrate on which the conductive film is formed. Because of this, it is difficult to define the forming position and make a uniform forming shape. When the forming position is changed, the position of the emitted electron beam is changed, and when the irregular forming form is made, the electron emission characteristics are easily changed, and when applied to the display, the uniformity is deteriorated.

After the above-mentioned forming process is completed, the activation unit 104 is formed by combining a material that emits electrons such as carbon or a semiconductor material well around the edge of the forming gap formed through the activation step to improve the emission characteristics of the device. Improve. This takes a process of coating a carbon film in the vicinity of the gap by applying a pulse voltage in a manner similar to the energizing process in the organic gas atmosphere to cause gas decomposition between the gaps. Through this activation step, the number of emitting electrons increases rapidly and functions as an electron emission source device.

FIG. 2 shows a basic structure of a display (SED) using an SCE element, and includes a lower plate on which the above-described element is disposed and an upper plate generating visible light by emitted electrons.

In the upper plate, an RGB phosphor pattern 202 is formed on a substrate 201 such as glass or quartz, and an anode (also called a metal back) electrode 203 is disposed thereon. The two substrates are separated and supported by separate spacers, and maintain a high vacuum therein to prevent the electron beam from colliding with the gas. When voltage is applied to the two electrodes of the lower plate, electrons are emitted from the one edge of the conductive layer 103 by the electron tunneling phenomenon to the other gate, This phenomenon is known as the field emission phenomenon by the electric field. In SCE, this general tunneling phenomenon is known to be accompanied by the addition of small particles between the gaps and the like, and some of the electrons that have repeated this tunneling and collision are multiplied on the gate electrode. Through the scattering phenomenon, it is attracted by the electric field of the anode electrode 203 of a very high top plate, accelerates to the top plate, collides with the phosphor, and emits visible light by electroluminescence (Electro-Luminescence).

Therefore, the most urgent and fatal problem of the conventional SCE and the display using the same is low uniformity, and the cause of the characteristic variation of the individual elements is the formation of an irregular forming gap. That is, the improvement of the process which can form the conductive film of many SCE elements in a uniform form and position is absolutely required.

As described above, in the conventional surface conduction electron-emitting device, a conductive film is formed between the lower electrodes and then energized and formed to form a forming gap in the conductive film between the electrodes. There was a fatal problem that is severe enough to form a characteristic variation between the elements so that it is difficult to implement a display panel.

In view of the above problems, the present invention forms a single layer or a plurality of conductive layers between electrodes formed on a substrate, and forms a conductive gap after defining a region in which a forming gap is formed by etching a portion of the conductive layer. The purpose of the present invention is to provide a surface conduction electron-emitting device and a method for manufacturing the same, in which a forming gap is formed only in a conductive film region having a reduced thickness, thereby forming a forming gap of all devices in a desired position and shape to reduce variations between devices. have.

The present invention for achieving the above object is a substrate with a pair of electrodes formed; A conductive film disposed between at least one of the electrodes while being connected to the electrodes, wherein a region including a forming gap is partially removed in a thickness direction; And a forming gap formed in the conductive film of the removed region.

The conductive layer may include a first conductive layer having a removal region for defining a region in which a forming gap is to be formed; And a second conductive film formed over the first conductive film and having a forming gap formed at a portion of the first conductive film in a region where the first conductive film is disposed.

The conductive film is disposed between the electrodes and has a forming gap formed therein; A region formed on the first conductive layer and including a region in which a forming gap of the first conductive layer is formed may include a second conductive layer partially removed in a thickness direction.

In addition, the present invention comprises the steps of forming a pair of electrodes on the substrate; Forming at least one conductive film to electrically connect the electrodes, and removing at least a portion of the region including a portion in which a forming gap is to be formed in a thickness direction when the conductive films are formed in a predetermined order; And forming a forming gap in the conductive film region from which the portion is removed by applying a voltage to the electrode.

In the forming of the conductive film, removing at least a portion of the region including a portion to form the forming gap in the thickness direction may include removing the conductive film pattern including the removal region in the deposition step by using a mask on which the conductive film pattern and the removal region pattern are formed. And directly depositing.

When described in detail with reference to the accompanying drawings, the present invention as follows.

3A to 3B are cross-sectional views and a plan view of an embodiment of the present invention, in which two conductive layers 303 and 304 are formed to electrically connect electrodes 301 formed on the substrate 302 as shown. In this case, a groove 305 is formed by removing a part of the upper conductive layer 303 to define a region in which a forming gap is to be formed.

That is, as shown in FIG. 3A, an electrode 301 to be used as a cathode and a gate is formed, and an appropriate conductive film 304 is formed to a thickness such that cracks are caused by energizing forming while electrically connecting the electrodes. In addition, after the new conductive film 303 is formed for the purpose of designating the forming region thereon again, the groove 305 is formed by etching the electrode 301 in parallel with the electrode 301 to form the conductive film ( 304 is the thinnest portion of the entire conductive film and the portion having the largest resistance, so that a crack, that is, a forming gap, is formed only in the portion during the energizing forming process. Thus, when forming a conductive film in which some regions have been removed 305 by etching or otherwise, the size of the removed region is wider than the forming gap formed by the energizing forming, which is used for patterning the conductive film 303. As technology develops, it can be narrowed gradually, and can be made narrower in reality by various application technologies. As such, the structure defining the region in which the forming gap is to be formed can be more accurately confirmed through FIG. 3B.

The above embodiment shows only one structure among various applications of the present invention, and specific contents of the various applications will be described with reference to FIGS. 4 to 5.

4 is a cross-sectional view illustrating a manufacturing process of an embodiment of the present invention and is one of methods of forming a plurality of conductive films.

First, as shown in FIG. 4A, an electrode pattern 402 to be used as a cathode electrode and a gate electrode is formed on the substrate 401. It is patterned after film formation using methods such as vacuum deposition, screen printing, inkjet printing, and the like, in order to lower the resistivity of the electrode, Ag paste or the like is thick-printed by screen printing to reduce wiring resistance. At this time, the electrode mainly uses Pt, and is deposited by sputtering or e-beam deposition, and then electrode patterns are formed in advance by patterning and etching by photolithography. After that, Ag paste is printed by thick film printing method to connect each electrode, and then the electrode pattern is completed through exposure and development. The thick film printed electrode wiring is several micrometers thick and has a very low resistance. Therefore, the present invention may be applied to a large display substrate, and may be formed by a single metal process when used as a small display or an individual device.

As shown in FIG. 4B, the formed electrodes 402 are electrically connected using the first conductive layer 403. The first conductive film 403 is a method of performing direct printing using inkjet printing, vacuum deposition, spin coating, and the like and then patterning by photolithography. However, it may be formed by a method of directly patterning during vacuum deposition using a shadow mask, or other electrochemical deposition or spray method. The first conductive film 403 formed primarily may be additionally heat treated according to a process. In particular, in the case of PdO, which is mainly used as a conductive film, a process of oxidizing PdO by depositing Pd and heat treatment in an oxygen atmosphere is used.

As shown in FIG. 4C, a second conductive film 404 having a removal region parallel to the electrode 403 is formed on the first conductive film 403. The second conductive film 404 may also be formed in the same manner as the first conductive film 403. The removal of the predetermined region may be performed by using simple etching, physical polishing, and blades after forming the conductive film 404. The second conductive film 404 in the corresponding region may be completely removed by the physical method. If a part of the second conductive film 404 is removed through the removal process, all of the second conductive film 404 in the desired region may not be completely removed but may be incompletely removed. Removal is irrelevant. In other words, since the present invention aims to lower the thickness of some regions of the entire conductive film so as to increase the resistance of the regions, the completeness of the trench formation is irrelevant to the implementation of the present invention. Rather, incomplete removal can further narrow the width of the area being removed, allowing more precise and fine control of the area where the forming gap is to be formed.

In addition, unlike the method of forming and patterning the second conductive film 404 as described above, if the patterning is performed simultaneously with deposition using a mask, not only the shape of the conductive film but also the removal region formed on the conductive film may be applied to the mask. By definition, a conductive film pattern having a removal region may be formed at the same time as deposition. In addition, if the shadow effect generated by deposition using a mask is intentionally used, the removal region may be further narrowed, so that the present invention may be applied even when a conductive film having the removal region is formed using a material that is difficult to etch. do.

5 is a procedure cross-sectional view for manufacturing a structure according to another embodiment of the present invention, in which a removal region is formed in the first conductive film 403 and a second conductive film 404 is formed thereon. It defines the trench area in which the forming gap is to be formed.

First, as shown in FIG. 5A, the electrodes 402 are formed on the substrate 401, and as illustrated in FIG. 5B, the first conductive layer 403 including the removal region parallel to the electrode 403 has been described above. It is formed using various methods. As shown in FIG. 5C, a second conductive film 404 is formed on the first conductive film 403, and the second conductive film is formed on the removal region formed in the first conductive film 403. The portion 404 is formed to have the largest resistance (the thinnest overall thickness). This simply changes the order in which the conductive film including the removal region is formed in the procedure shown in FIG. 4, and even if the order is changed, all of the above objects are met.

Subsequently, when energization is performed by applying a voltage to the conductive films 403 and 404 formed as described above, cracks are generated only in the conductive film positioned at the portion where the removal region is formed to form a forming gap. Therefore, the thickness of the thinnest portions of the conductive films should be within the thickness where cracks may occur by energizing forming.

4 to 5, in the case of forming two or more conductive films 403 and 404 separately, heat treatment may be performed after the formation of each conductive film, and a plurality of conductive films may be formed. After the additional heat treatment as a whole, it is possible to lower the bonding resistance between the conductive layers and increase the hardness so that cracks having sharp edges are easily formed when the energizing forming is formed.

Although FIGS. 4 to 5 stack a plurality of conductive films and use a method of removing a predetermined region of one of the conductive films, a forming gap may be formed only in a corresponding region by arbitrarily lowering the thickness of the conductive film in a desired region. After forming a single conductive layer, the same effect may be obtained when only a portion of the region to be defined to form the forming gap is removed in the thickness direction. Therefore, this method can be used when using a conductive film made of a material which is easy to remove some regions. On the other hand, since etching or polishing may be difficult depending on the material of the conductive film, in this case, it is preferable to apply a structure composed of a plurality of conductive films as in the above-described embodiments.

Figure 6 is a micrograph showing the practical results of the present invention, it can be seen that the forming gap is formed in a straight line only within the region defined by physical or chemical techniques.

As described above, the surface conduction electron-emitting device of the present invention and a method of manufacturing the same are formed by forming a single layer or a plurality of conductive layers between electrodes formed on a substrate and etching a portion of the conductive layer to define a region in which a forming gap is to be formed. The forming gap is formed only in the conductive film region where the thickness is reduced by the removal region, thereby forming the forming gaps of all the elements in a desired position and shape, increasing the precision of the forming gap position, and greatly increasing the characteristic variation between the elements. When the device is applied to a display panel, there is an excellent effect of dramatically improving the quality and yield of the display image.

Claims (11)

A substrate on which a pair of electrodes are formed; A conductive film disposed between at least one of the electrodes while being connected to the electrodes, wherein a region including a forming gap is partially removed in a thickness direction; And a forming gap formed in the conductive film of the removed region. The semiconductor device of claim 1, wherein the conductive layer comprises: a first conductive layer having a removal region for defining a region in which a forming gap is to be formed; And a second conductive film formed over the first conductive film and having a forming gap formed in a portion of the first conductive film in a removal region of the first conductive film. The semiconductor device of claim 1, wherein the conductive film comprises: a first conductive film disposed between electrodes and having a forming gap formed thereon; And a second conductive film formed over the first conductive film and including a region in which a forming gap of the first conductive film is formed, the second conductive film being partially removed in a thickness direction. The surface conduction electron emission device of claim 1, wherein the conductive film is formed in a single layer and defines a region in which a forming gap is to be formed by removing only a portion of the conductive film in a thickness direction. Forming a pair of electrodes on the substrate; Forming at least one conductive film to electrically connect the electrodes, and removing at least a portion of the region including a portion in which a forming gap is to be formed in a thickness direction when the conductive films are formed in a predetermined order; And forming a forming gap in the conductive film region from which the portion is removed by applying a voltage to the electrode. The method of claim 5, wherein the forming of the conductive film comprises: forming a first conductive film between the electrodes; Forming a second conductive film on the first conductive film and then etching the second conductive film in a direction parallel to the electrodes to reduce the height of the conductive film of the etched portion; Method of manufacturing the emitting device. The method of claim 5, wherein the forming of the conductive film comprises: forming a first conductive film between the electrodes and etching at least a portion of the first conductive film in a direction parallel to the electrodes; Forming a second conductive film on the first conductive film, characterized in that it comprises a surface conduction electron-emitting device manufacturing method. The method of claim 5, wherein the forming of the conductive film comprises etching a portion of the conductive film in a direction parallel to the electrodes after forming a single conductive film. The method of claim 5, wherein the conductive film comprises: stacking a plurality of conductive film layers; The method of manufacturing a surface conduction electron-emitting device further comprising the step of separately heat-treating the individual laminated conductive films. The method of claim 5, wherein the removing of at least a portion of the region including the portion to form the forming gap in the thickness direction of forming the conductive layer is performed by removing the region in the deposition step using a mask on which the conductive layer pattern and the removal region pattern are formed. Surface conduction electron-emitting device manufacturing method comprising the step of directly depositing a conductive film pattern comprising a. The method of claim 10, further comprising reducing a width of the removal region by using a shadow effect when the conductive layer pattern is directly deposited using the removal region pattern formed on the mask.

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