KR20040070626A - Field emission device and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A field emission device and a method for manufacturing the same are provided to achieve improved insulation between electrodes and prevent breakdown of the device. CONSTITUTION: A field emission device comprises a lower electrode(24) on which a tunnel oxide film(26) and an anode insulation film are formed; an upper data electrode(28) having an opening and a bus structure formed on the lower electrode; an insulation layer formed on the upper data electrode, and which has an opening; an upper electrode separating layer(32) disposed on a certain part of the insulation layer and in a spacer mounted area, wherein the upper electrode separating layer has a plating seed layer formed underneath the upper electrode separating layer; and a top electrode(33) formed all over the resultant structure, and partially separated by the upper electrode separating layer.

Description

Field emission device and manufacturing method thereof {FIELD EMISSION DEVICE AND MANUFACTURING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission device and a method of manufacturing the same, and particularly, to improve insulation between top electrodes and to prevent device deterioration due to spacers in a display structure consisting of a field emission device using a metal insulating metal (MIM) bottom plate. A field emission device and a method of manufacturing the same.

Display elements have been rapidly developed in accordance with the demands of various display elements. Recently, as devices using field emission have been applied to display fields, development of thin film displays that can provide high resolution while reducing size and power consumption has been actively developed.

The thin film field emission device uses a quantum mechanical tunneling phenomenon in which electrons are released from the metal or the conductor into the vacuum when a high field is applied to the metal or the conductor surface in the vacuum. The thin film field emission device has a metal insulating metal (MIM) structure including a lower electrode supplying electrons, an insulating film through which electrons tunnel, and a top electrode for applying an electric field to the insulating film.

1A to 1G are cross-sectional views of a conventional field emission device fabrication process using a MIM structure. As shown in FIG. 1A through FIG. 1G, an opening in which electrons are formed by forming a lower electrode 4 and an upper electrode 8 and 11 using various laminated films is illustrated. Release from.

First, as shown in FIG. 1A, SiO and SiN x are sequentially deposited on the upper plate glass 1 to form a first buffer layer 2 and a second buffer layer 3, and then wireless magnetron sputtering ( An aluminum thin film is deposited by Rf Magnetron Sputtering) or a chemical vapor deposition method, and patterned to form a lower electrode 4.

Next, as shown in FIG. 1B, a photoresist PR pattern is formed at the center of the lower electrode 4, and then an anode oxide film 5 is formed on the exposed lower electrode 4. The anodic oxidation is an anodic oxide film of Al ₂ O ₃ by oxidizing aluminum by applying a DC voltage of about 30 to 160 V at both ends using a specimen of the lower electrode 4 as a cathode in a phosphoric acid or oxalic acid solution, and using platinum as a cathode on the opposite side. (5) is formed.

Next, as shown in FIG. 1C, the photoresist PR is removed, and a tunnel oxide film 6 is formed as a thin film through anodization on the exposed lower electrode 4. The tunnel oxide film 6, which is the thin film, is formed by about 100 kV by an anodic oxidation voltage of less than 10 V, and passes electrons by a high voltage applied while insulating the lower electrode 4 and the upper electrode 11 to be formed later. do.

Next, as shown in FIG. 1D, the double insulating film 7, the aluminum upper data electrode 8, the first overhang film 9, and the second overhang film 10 are sequentially disposed on the entire upper surface of the structure. After deposition, the second overhang film 10 and the first overhang film 9 are dry-etched using the photoresist pattern for forming the data electrode bus, and the upper data electrode 8 is wet-etched to wet the data electrode bus pattern. To form.

Next, as shown in FIG. 1E, when the second overhang layer 10 and the first overhang layer 9 are dry-etched according to the electron emission region to form an opening, the first overhang layer 9 is etched. The overhang structure is formed because the speed is faster than that of the second overhang film 10. The overhang of this structure is called a normal overhang.

Next, as shown in FIG. 1F, the exposed upper data electrode 8 is wet etched and the lower double insulating layer 7 is dry etched to form an electron emission opening to expose the lower tunnel oxide layer 6. .

Then, as shown in FIG. 1G, to recover the damage of the tunnel oxide film 6 by the etching process, the tunnel oxide film 6 is etched back and reoxidized to form Ir / Pt / Au is deposited to form the top electrode 11. Since the top electrode 11 is formed, the portion formed on the tunnel oxide film 6 becomes a part emitting electrons, so it is also called an emitter.

Conventionally, all of the electroluminescent elements constituting the display panel are formed to be substantially the same. Then, to look at the structure of the actual electroluminescent device to which the top plate is applied to the lower plate of the electroluminescent device formed.

2 is a cross-sectional view of a conventional field emission device. As shown in the drawing, a vacuum area is formed between a lower plate (cathode) 1 to 11 of the device and an upper plate (anode) 14 and 15 of the device. The spacer 12 and the frit 13 are installed for the maintenance.

As described above, after manufacturing the lower plate, the spacer 12 is mounted on the lower plate, and a frit 13 is installed to maintain vacuum tightness. To make the interior vacuum.

When an electric field is applied to the lower electrode 4 and the upper electrodes 8 and 11 of the field emission device as described above, electrons are emitted. The electron beam is spread in a vacuum as shown in FIG. Proceed to However, since the traveling direction is distorted by the electrons accumulated in the space 12 mounted on the side surface, the spacer 12 is grounded to discharge the charged charge.

The spacer 12 is formed in a rib type and a segment type. The lip type is mechanically stable, easy to manufacture, and a ground electrode can be formed directly under the spacer, but exhaust and vacuum are difficult and visible from the outside. It cannot be applied to large area panels. Segmented shapes are easy to exhaust and vacuum and are not visible from the outside, but the manufacturing process is complicated and the electrodes cannot be formed directly on the spacers and must be formed on the bottom plate.

3A illustrates a method of mounting the lip spacer on the lower plate, and the spacer on which the lower electrode is formed is mounted in parallel to the lower electrode. Therefore, no separate process is required on the lower plate.

3B illustrates a method of mounting the segmented spacer on the lower plate, and thus no electrode is formed on the spacer. Therefore, in order to prevent electric field distortion by the spacer, a spacer electrode must be formed on the lower plate.

As described above, the spacer is mounted parallel to the lower electrode, and the lower plate element is physically destroyed by the mechanical mounting of the spacer. Electrodes pass under the spacer, and a short circuit between upper and lower electrodes may occur due to spacer mounting, and disconnection may occur when formed on the upper electrode.

The overhang layer is a general overhang method for electrically separating the uppermost insulating film inside the opening and the outer side of the electrode, and the side overhang method for electrically separating the connection between the electrodes by the shape of the electrodes, as described above. have.

4 is a structural cross-sectional view showing an insulating method between the uppermost electrodes in the bottom of the field emission device to which the side overhang is applied. As illustrated, an upper data electrode 8 is formed on the double insulating film 7, and a side overhang film 9 is formed on the double insulating film 7. The overhang layer 9 is etched and the upper data electrode 8 at the bottom thereof is etched to form an opening, and the outer side surfaces of the electrode are over-etched to form an overhang structure under the overhang layer 9. When the top electrode 11 is formed on the structure, insulation between the data electrode bus structures is achieved by the overhang structure. Therefore, it can be seen that the uppermost electrodes 11 formed on the two field emission elements shown are separated from each other and separated from the data electrode buses. Accordingly, the side overhang layer 9 may be formed of an insulator or a conductor material.

As described above, by placing the same undercut area in both the general overhang structure and the side overhang structure, the uppermost electrode 11 formed thereon is cut off by the corresponding overhang structure, and the upper part adjacent through the disconnection is formed. Insulation between the data electrodes 8 is ensured.

For such overetching, dry etching processes using wet etching or etching layers having different etching ratios are used, and the photoresist process, etching process, and cleaning process are repeated, thereby destroying the overhang structure having the excess etching region underneath. Or collapse. This collapse reduces the insulating properties between the electrodes when the top electrode 11 is formed, causing unwanted short circuits or leakage currents.

As described above, the conventional field emission device insulates the electrode buses of the top electrode by the overhang structure, but the structurally fragile overhang structure is easily collapsed by a number of processes for forming the overhang structure. There is a problem that short-circuit or leakage current is caused between them, and there is a problem that short-circuit of the upper and lower electrodes or disconnection of the upper electrode by the spacer to be mounted thereafter.

In view of the above problems, the present invention is to form an upper electrode separation layer on the upper portion thereof without physically fragile overhang structure to improve insulation properties between electrodes of the uppermost electrode, and to connect the spacer through the plating process. An object of the present invention is to provide a field emission device and a method of manufacturing the same.

1A to 1G are cross-sectional views of a conventional process for manufacturing a field emission device.

2 is a cross-sectional view showing a structure of a field emission device to which a general overhang is applied;

Figure 3 is a cross-sectional view showing a portion of the field emission element and the bottom coupling structure.

4 is a cross-sectional view showing the structure of a field emission device to which a side overhang is applied.

5A to 5D are cross-sectional views of a manufacturing process of the field emission device of the present invention.

6 is a cross-sectional view of an embodiment of the field emission device to which the present invention is applied.

7A-7D are cross-sectional views showing other structures of the present invention.

8 is a plan view illustrating an electrode structure to which an upper electrode isolation layer is applied.

FIG. 9 is a plan view showing a structure in which a top electrode layer is formed in FIG. 8; FIG.

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

21: bottom glass 22: first buffer film

23: second buffer film 24: lower electrode

25: anode oxide film 26: tunnel oxide film

27: double insulating film 28: upper data electrode

29: overhang 30: plating seed layer

31: plating mold 32: upper electrode separation layer

33: top electrode

According to an aspect of the present invention, there is provided a light emitting device including: a lower electrode having an electron emission tunnel oxide film and an anode insulating film formed thereon; An upper data electrode having an opening and a bus structure positioned above the lower electrode; An insulating layer on the upper data electrode and having an opening structure; An upper electrode isolation layer positioned in a portion of an upper portion of the insulating layer around the opening and in a spacer mounting region and having a plating seed layer under the insulating layer; Located on the upper front surface of the structure, characterized in that it comprises a top electrode partially separated by the upper electrode separation layer.

The upper electrode separation layer positioned in the spacer mounting region is connected to the spacer and serves as a lower electrode and a buffer layer of the spacer.

In addition, the present invention comprises the steps of forming a lower electrode on the substrate with a tunnel oxide film and an anode insulating film formed on the upper substrate; Forming a double insulating film, an upper data electrode, and an insulating film on the entire upper surface of the structure in turn and patterning the insulating film; Forming a plating seed layer on the entire upper surface of the structure; Forming a plating mold on the plating seed layer, the plating mold having a portion patterned around a portion where an electron emission opening is to be formed; And forming the upper electrode separation layer by plating using the plating mold, and then removing the plating mold.

The forming of the plating mold may further include forming a pattern for forming a spacer connection portion at a portion on which the spacer is to be mounted, wherein the plating may include forming an upper electrode separation layer and a spacer by plating using the plating mold. And forming a connection at the same time.

When described in detail with reference to the accompanying drawings an embodiment of the present invention configured as described above are as follows.

5A to 5D are cross-sectional views of the manufacturing process steps of the embodiment of the field emission device of the present invention, and the plating seed layer on the upper overhang insulating layer 29 before the opening is formed, as shown only by the core of the present invention. Forming 30 (FIG. 5A); Forming a plating layer on a portion of the periphery of the plating seed layer 30 on which a later opening is to be formed and forming a plating mold 31 for forming the plating layer on the spacer mounting region (FIG. 5B); Forming an upper electrode isolation layer 32 and a spacer connection part (not shown) by plating using the formed plating mold and the plating seed layer 30 (FIG. 5C); Removing the plating mold 31 and removing the exposed portion of the plating seed layer 30 using the formed upper electrode isolation layer 32 and the space connecting portion as a mask (FIG. 5D).

This will be explained in more detail.

First, as shown in FIG. 5A, a plating seed layer 30 is formed on an upper portion of the lower plate structure of the field emission device formed by the conventional method. In some structures of the lower plate of the field emission device, a lower electrode on which a tunnel oxide film and an anode insulating film are formed is formed on a substrate in the same step as the conventional art, and a double insulating film, an upper data electrode, and an overhang insulating film are sequentially formed on the entire upper surface of the structure. It is formed and patterned according to the electrode structure. Here, the overhang insulating film acts as an insulating film, and it is not necessary to substantially undercut the lower layer of the heterogeneous laminated film.

Next, as shown in FIG. 5B, a plating layer 31 is formed on a portion of the periphery of the plating seed layer 30 in which a later opening is to be formed, and a plating mold 31 for forming the plating layer in the spacer mounting region is formed. . The plating mold 31 is a photoresist pattern for defining a structure in which a plating layer is formed through plating, and is formed in an inverted trapezoid in the present embodiment, but may have a different structure. Since the spacer part is not shown in the figure, the spacer part will be described in more detail later.

Next, as illustrated in FIG. 5C, the upper electrode isolation layer 32 and the spacer connection part (not shown) are formed by plating using the formed plating mold and the plating seed layer 30.

Next, as shown in FIG. 5D, the plating mold 31 is removed, and the exposed portion of the plating seed layer 30 is removed using the upper electrode isolation layer 32 and the spacer connection portion formed as a mask. In the present embodiment, after depositing the plating seed layer 30, the plating mold 31 is directly formed on the upper portion of the plating seed layer 30 to expose only the portion to be plated, and the plating is performed. 30) used to remove. However, after the plating seed layer 30 is formed, plating may be performed by applying the plating mold 31 after patterning according to a portion to be plated.

After forming as described above, the electron-emitting opening is formed through the formation of the overhang structure and the opening patterning, and then the uppermost electrode is formed on the upper front surface, and the uppermost electrode is insulated from inside and outside the data electrode by the upper electrode separation layer. That is, by using this, it is possible to achieve complete insulation between adjacent electrodes without having to form an overhang structure. Incidentally, the cross-sectional view of the present embodiment emphasizes variations (historical trapezoids) in the thickness and width of the upper electrode separation layer, and does not need to be close to the openings, and thus does not affect the actual opening formation.

6 illustrates a case where the present invention is applied to a side overhang structure electroluminescent device. As shown, the overhang structure is not formed, and it can be seen that the overhang layer 29 simply acts as an insulating layer. That is, since the overhang structure does not have to be made while taking structural weaknesses, the overhang layer 29 is collapsed due to process stimulus.

The uppermost electrode 33 formed thereon by the upper electrode isolation layer 32 formed on the overhang layer 29 is cut twice on the inside and the outside of the data electrode bus. That is, the insulation characteristics are remarkably improved, and short circuits or leakage currents due to collapse or destruction of the overhang layer 29 can be prevented, thereby providing an electrically stable operating environment.

The upper electrode isolation layer 32 is an inverted trapezoidal shape, which is an optimal embodiment for increasing insulation, which is an object of the present invention, and forms a plating mold having a slight inclination since the photoresist pattern is etched to form a plating mold. . However, the present invention is not limited to this specific form and may have various forms of the upper electrode isolation layer 32. Some of these are shown in FIG.

FIG. 7A shows that the upper electrode isolation layer 32 is inclined only toward the opening and separates the uppermost electrode from the opening.

FIG. 7B is for separating the top electrode on the outer side of the electrode as opposed to FIG. 7A.

The vertically formed portions in FIGS. 7A and 7B can also separate the top electrode, which is determined by the aspect ratio of the vertical portion. The top electrode is a thin film having a thickness of about 50 to 100Å, and is formed through sputter deposition, so the amount deposited on the vertical sidewalls is insufficient. It is removed through self thinning. As such, a form such as that shown in FIG. 7C is also possible.

Reference is now made to spacers for supporting the bond with the top plate.

FIG. 8 is a top plan view of the scan-data electrode before the top electrode is formed. As shown in FIG. 8, the spacer is disposed in parallel with the bottom electrode connected to the scan electrode. Should be formed. Conventionally, a conductive layer is newly formed for this purpose, and a buffer layer through the plating layer is newly formed to prevent the lower structure from being destroyed. However, in the present invention, as shown in the drawing, the upper electrode isolation layer 32 is formed on the data electrode and the plating spacer connection portion is formed in the region where the spacer is to be mounted. It is also used as a buffer layer for buffering and at the same time as the lower electrode for releasing the charge accumulated in the spacer to mitigate the impact on the structure under the spacer.

FIG. 9 is a top electrode formed on the formed electrode structure (FIG. 8), and is formed on the spacer connection part, the bottom electrode (substantially an insulating film formed on the bottom electrode), and the top electrode separation layer. When the film is formed in this way, pieces are separated by the upper electrode separation layer as shown in the enlarged view. The top electrode formed inside the opening acts as an emitter of the electron emission portion, and the top electrode is separated between the data electrode buses.

As described above, the field emission device of the present invention is formed by plating the upper electrode separation layer around the upper portion of the lower plate opening of the device to form a spacer connection at the same time, thereby providing insulation between the electrodes from forming the top electrode without structurally weak overhang structure. Of course, by providing a spacer electrode there is an effect that can improve the inter-electrode insulation, prevent the destruction of the device and provide the electrode and the buffer function to the spacer mounting portion.

Claims (5)

A lower electrode having an electron emission tunnel oxide film and an anode insulating film formed thereon; An upper data electrode having an opening and a bus structure positioned above the lower electrode; An insulating layer on the upper data electrode and having an opening structure; An upper electrode isolation layer positioned in a portion of an upper portion of the insulating layer around the opening and in a spacer mounting region and having a plating seed layer under the insulating layer; And a top electrode positioned on an upper surface of the structure and partially separated by the upper electrode separation layer. The field emission device of claim 1, wherein the upper electrode isolation layer positioned in the spacer mounting region is connected to the spacer and serves as a lower electrode and a buffer layer of the spacer. Forming a lower electrode on which a tunnel oxide film and an anode insulating film are formed on the substrate; Forming a double insulating film, an upper data electrode, and an insulating film on the entire upper surface of the structure in turn and patterning the insulating film; Forming a plating seed layer on the entire upper surface of the structure; Forming a plating mold on the plating seed layer, the plating mold having a portion patterned around a portion where an electron emission opening is to be formed; And forming the upper electrode separation layer by plating using the plating mold, and then removing the plating mold. The method of claim 3, wherein the seed layer used for plating is patterned according to a plating region and then used for plating, or patterned after plating. The method of claim 3, wherein the forming of the plating mold further comprises forming a pattern for forming a spacer connection portion at a portion on which the spacer is to be mounted, wherein the plating is performed by plating using the plating mold. A method of manufacturing a field emission device further comprising: simultaneously forming an upper electrode separation layer and a spacer connection part.