JP2000208035A - Forming method of minute opening, field-emitting cold cathode and its manufacture, and flat-panel image device using same field-emitting cold cathode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method of a minute opening, improving controllability of an emitter shape, simplifying a manufacturing process, and realizing uniform emission of electrons, provide a field emitting cold cathode and its manufacturing method, and provide a flat-panel image device using the same field emitting cold cathode. SOLUTION: This method of manufacturing a field emitting cold cathode includes a process for forming, on a glass substrate 1, a conductive layer 2 made of poly-silicon, etc., an insulating layer 3 made of an oxide film, a gate electrode layer 4, and an oxide film 5 serving as a thin film for emitter area formation, in order, a process for forming a first opening part by etching the oxide film 5 serving as a thin film for emitter area formation, a process for arranging mask materials in the first opening part, a process for forming second opening parts by etching the gate electrode layer and insulating layer in the first opening part with the mask materials used as mask, a process for forming pointed emitter tips in the second opening parts by depositing an emitter material from above the substrate, and a process for removing the emitter material deposited on other portions than the emitter tips, the mask materials, and the oxide film 5 for emitter area formation by etching them, after the emitter material is deposited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to all devices having a minute opening, and is used, for example, as an electron beam source for flat panel displays, CRTs, electron microscopes, electron beam exposure apparatuses, and various electron beam apparatuses. Field of the Invention The present invention relates to a method for forming a small opening, a field-emission cold cathode, and a method for manufacturing the same, and a flat image device using the field emission cold cathode.

[0002]

2. Description of the Related Art In recent years, a field emission type in which a sharpened cathode emitter is integrally formed in a substrate, a conductive layer, an insulating layer, a gate electrode layer, and a minute opening thereof using a semiconductor fine processing technique. Active research and development of cold cathodes,
It is expected to be applied to high-performance electron guns and the like.

As an example of a conventional method of manufacturing a field emission cold cathode, see Journal of Applied Physics, Vol. 47 (1976).
Have described a method of manufacturing a field emission cold cathode using molybdenum, which is a high melting point metal, in view of generation of high emission current density and controllability. FIG. 5 shows a conventional manufacturing method.

In FIG. 5A, an N-type highly doped Si (conductive layer 52) and a Si
An insulating layer 53 made of O ₂ and a gate electrode layer made of molybdenum are sequentially deposited by sputtering.

In FIG. 5B, a circular opening having a diameter of about 1.5 μm is formed by an etching process. The insulating layer 53 below the opening of the gate electrode is etched with hydrofluoric acid to widen only the opening diameter of the insulating layer 53 as shown in FIG. Thereafter, as shown in FIG. 5D, an aluminum layer is deposited at oblique incidence while rotating the substrate. Hereinafter, this aluminum layer is referred to as a sacrifice layer 63. The sacrificial layer 63 formed by oblique incidence is deposited only on the upper part of the gate electrode layer 54 and its side wall. After the sacrifice layer 63 is formed, molybdenum as an emitter material is vertically deposited on the conductive layer 52 by a method such as evaporation in a high vacuum. As the deposition of molybdenum progresses, molybdenum also condenses around the opening of the sacrificial layer 63, the opening diameter gradually decreases, and the opening is finally closed as shown in FIG. At the same time, a cone-shaped emitter 58 is formed on the conductive layer 52.

[0006] As shown in FIG.
The emitter material 57 deposited thereon is simultaneously removed by etching the sacrificial layer 63, and finally the insulating layer 53 and the gate electrode layer 54 formed on the conductive layer 52
Cone-shaped emitter 58 with a sharp tip in the opening of
Is formed.

A plurality of such emitters 58 can be arranged as shown in the figure. A gate voltage of 100 to 300 volts with respect to the emitter potential is applied to the tip of the emitter 58 so that 50 to 50 chips per chip can be obtained. It is described that about 150 microamps of electrons can be emitted into a vacuum.

Further, such a field emission type cold cathode is used as an electron source for a thin flat panel image device. FIG.
FIG. 1 is a schematic diagram showing a cross-sectional structure when a planar image device is configured using the above-described conventional technology. By arranging two-dimensionally in a vacuum envelope sealed as shown in FIG. 6, it is possible to use it as an electron source of a flat panel image device.

A conductive layer 52 is formed on a glass substrate 51,
A plurality of emitters 58 corresponding to each pixel are formed by the method described above. R (red), G (green), and B (blue) phosphors 60 are regularly arranged two-dimensionally via a transparent electrode 59 on a glass substrate 51 ′ at a position facing the emitter 58. I have. The spacing between the spacers 61 is preferably as dense as possible for each pixel, but is regularly arranged for each of a plurality of pixels in terms of alignment and throughput. The inside of the planar image device is kept in a vacuum, and the electrons emitted from the emitter 58 collide with a desired phosphor 60 arranged at a position facing to the image, so that an image can be obtained. Since the inside of the device is kept in a vacuum, a spacer 61 is provided for each of a plurality of pixels so that the gap (distance in the device) between the emitter 58 and the phosphor 60 is not compressed by the atmospheric pressure.
The installation of the spacer 61 is performed immediately before the two glass substrates on which the emitter 58 and the phosphor 60 are formed, independently of the emitter forming step.

[0010]

However, as shown in the above prior art, the method of manufacturing a field emission cold cathode using a sacrificial layer involves forming an emitter and removing unnecessary emitter material deposited on the uppermost layer. However, the method using the sacrificial layer has a problem in that the film quality and controllability are poor, so that the emission current becomes non-uniform due to variations in the shape of the emitter. This is because the shape of the emitter formed in the gate opening greatly depends on the shape of the opening after the sacrificial layer is deposited.

For example, when the opening of the sacrifice layer is curved rather than circular, the shape of the emitter is necessarily distorted reflecting the shape of the sacrifice layer, or the emitter tip position is normal. Will be deviated from the correct position. In the emission current characteristics due to field electron emission, the degree of electric field concentration varies depending on the tip shape of the emitter and the position of the tip of the emitter with respect to the gate electrode, so the electron emission characteristics from the emitter formed through the sacrificial layer become non-uniform. However, there is a problem that the yield and reliability are reduced.

Further, since the sacrificial layer is deposited by oblique incidence while rotating the substrate, there is a problem that the process becomes complicated and an expensive and highly controllable device is required.

In addition, when used as an electron source for a flat panel image device or the like, there is a problem that when the screen is enlarged, the uniformity and controllability are further reduced.

[0014] Therefore, the conventional manufacturing method has a problem that the cost and the throughput are reduced, and the emission current becomes non-uniform.

The conventional manufacturing method requires a photolithography technique for etching a gate opening on the order of microns or submicrons. When manufacturing a large-screen planar image device, such fine patterning is difficult by batch exposure, and it is necessary to divide the pattern into a plurality of blocks. However, such a lithography process has a problem that it causes high cost and low throughput.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a step of densely arranging a plurality of mask members in a planar shape on a region to be etched; Forming an opening by etching a material to be etched by utilizing a gap between adjacent mask materials of the individual mask materials.

According to a second aspect of the present invention, in the first aspect, the mask member is spherical.

The third aspect of the present invention is the first or second aspect.
In the invention described above, the step of densely arranging a plurality of mask materials on a plane is characterized in that the conductive substrates are arranged while tilting and applying vibration.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the mask material is glass.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the conductive layer provided on the substrate, the insulating layer provided on the upper surface of the conductive layer, A gate electrode layer provided on the upper surface of the layer, a thin film for forming an emitter region provided on the upper surface of the gate electrode layer, a first opening formed by etching the thin film for forming the emitter region, Etching the gate electrode layer and the insulating layer in the first opening by using a plurality of mask materials densely arranged on a plane in one opening and using a gap between the arranged plurality of mask materials; Emitter material having a second opening formed by the above method, and an emitter tip deposited on the substrate and having a sharpened emitter tip in the second opening. The mask material and emitter area The thin film for forming, characterized in that it is formed by removing by etching.

According to a sixth aspect of the present invention, in the fifth aspect, the mask material is spherical.

The invention according to claim 7 is the invention according to claim 5 or 6.
In the described invention, a plurality of mask materials densely arranged on a plane are arranged while applying vibration while tilting the substrate.

According to an eighth aspect of the present invention, in the invention according to any one of the fifth to seventh aspects, the film thickness of the thin film for forming the emitter region is such that the radius of the mask material is R.
The film thickness is not less than R and not more than 3R.

According to a ninth aspect of the present invention, in any one of the fifth to eighth aspects, the thin film for forming the emitter region is an oxide film.

The invention according to claim 10 is the invention according to claims 5 to 9
In the invention described in any one of the above, the first opening is hexagonal.

The invention according to claim 11 is the invention according to claims 5 to 1
0, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.

According to a twelfth aspect of the present invention, there is provided an image processing apparatus comprising:
In the invention described in any one of the first to ninth aspects, the gate electrode layer is made of molybdenum of about 1 μm.

According to a thirteenth aspect of the present invention, a conductive layer provided on the substrate, an insulating layer provided on the upper surface of the transmission, a gate electrode layer provided on the upper surface of the insulating layer, A first thin film for forming an emitter region provided on an upper surface, a second thin film for forming an emitter region provided on an upper surface of the first thin film, and a first thin film and a second thin film for forming an emitter region; A first opening formed by etching a thin film, a plurality of mask materials densely arranged on a plane in the first opening, and a gap between the arranged plurality of mask materials are used. A second opening formed by etching the gate electrode layer and the insulating layer in the first opening, and an emitter tip which is formed by depositing an emitter material on the substrate and sharpened in the second opening; And deposited on other than emitter tip after deposition of emitter material Masking the emitter material member and a second
Is formed by removing the thin film by etching.

According to a fourteenth aspect, in the thirteenth aspect, the mask material is spherical.

According to a fifteenth aspect of the present invention, in the thirteenth or fourteenth aspect, the plurality of mask members densely arranged on a plane are arranged while tilting the substrate to apply vibration. It is characterized by the following.

According to a sixteenth aspect of the present invention, in the invention of any one of the thirteenth to fifteenth aspects, the total thickness of the first thin film and the second thin film for forming the emitter region is:
When the radius of the mask material is R, the film thickness is not less than R and not more than 3R.

According to a seventeenth aspect of the present invention, in any one of the thirteenth to sixteenth aspects, the second thin film for forming the emitter region is an oxide film.

According to an eighteenth aspect of the present invention, in the invention according to any one of the thirteenth to seventeenth aspects, the first thin film for forming the emitter region can be sufficiently etched by the step of etching the mask material and the second thin film. It is a material having a high etching resistance.

According to a nineteenth aspect, in the invention according to any one of the thirteenth to eighteenth aspects, the first opening is hexagonal.

According to a twentieth aspect of the present invention, in any one of the thirteenth to nineteenth aspects, the mask material is glass.

According to a twenty-first aspect of the present invention, the insulating layer according to any one of the thirteenth to twentieth aspects,
It is characterized by being constituted by an oxide film of approximately 2 μm.

According to a twenty-second aspect of the present invention, in any one of the thirteenth to twenty-first aspects, the gate electrode layer is made of molybdenum of about 1 μm.

According to a twenty-third aspect of the present invention, there is provided a method for forming a conductive layer on a substrate, forming an insulating layer on the upper surface of the conductive layer, forming a gate electrode layer on the upper surface of the insulating layer,
Forming a thin film for forming an emitter region on the upper surface of the gate electrode layer, forming a first opening by etching the thin film for forming the emitter region, and forming a plurality of masks in the first opening; A step of densely arranging the materials on a plane, and a step of forming a second opening by etching the gate electrode layer and the insulating layer in the first opening using gaps between the arranged masking materials. Depositing an emitter material from above the substrate to form a sharpened emitter tip in the second opening; and depositing the emitter material other than the emitter tip after depositing the emitter material to form a mask material and an emitter region. Removing the thin film by etching.

According to a twenty-fourth aspect of the present invention, in the twenty-third aspect, the mask member is spherical.

According to a twenty-fifth aspect of the present invention, in the invention of the twenty-third aspect or the twenty-fourth aspect, the step of densely arranging a plurality of mask members on a plane includes arranging the substrate while tilting the substrate and applying vibration. Features.

According to a twenty-sixth aspect of the present invention, in any one of the twenty-third to twenty-fifth aspects of the present invention, the thickness of the thin film for forming the emitter region is defined as follows: The film thickness is not less than 3R and not more than 3R.

According to a twenty-seventh aspect of the present invention, in any one of the twenty-third to twenty-third aspects, the thin film for forming the emitter region is an oxide film.

According to a twenty-eighth aspect of the present invention, in any one of the twenty-third to twenty-third aspects, the first opening is hexagonal.

According to a twenty-ninth aspect of the present invention, the insulating layer according to any one of the twenty-third to twenty-eighth aspects further comprises:
It is characterized by being constituted by an oxide film of approximately 2 μm.

According to a thirtieth aspect of the present invention, in any one of the twenty-third to twenty-third aspects of the present invention, the gate electrode layer is made of molybdenum having a thickness of about 1 μm.

The invention according to claim 31 is a method for forming a conductive layer on a substrate, forming an insulating layer on the upper surface of the conductive layer, forming a gate electrode layer on the upper surface of the insulating layer,
Forming a first thin film for forming an emitter region on the upper surface of the gate electrode layer, forming a second thin film for forming the emitter region on the upper surface of the first thin film, and forming a first thin film for forming the emitter region; Forming a first opening by etching the thin film and the second thin film, forming a plurality of mask members in the first opening densely on a plane, Forming a second opening by etching the gate electrode layer and the insulating layer in the first opening using the gap between the materials; and depositing an emitter material from above the substrate and sharpening the emitter material into the second opening. Forming a patterned emitter tip; removing the emitter material deposited on the portion other than the emitter tip after deposition of the emitter material by etching only a second thin film of a mask material and a thin film for forming an emitter region; Characterized in that it has a.

According to a thirty-second aspect, in the thirty-first aspect, the mask material is spherical.

According to a thirty-third aspect of the present invention, in the invention according to the thirty-first or thirty-second aspect, the step of densely arranging a plurality of mask members on a plane comprises arranging the mask members while tilting the substrate and applying vibration. It is characterized by doing.

According to a thirty-fourth aspect of the present invention, in the invention according to any one of the thirty-first to thirty-third aspects, the film thickness obtained by adding the first thin film and the second thin film for forming the emitter region is:
When the radius of the mask material is R, the film thickness is not less than R and not more than 3R.

The invention according to claim 35 is characterized in that, in the invention according to any one of claims 31 to 34, the second thin film for forming the emitter region is an oxide film.

According to a thirty-sixth aspect of the present invention, in the first aspect of the present invention, the first thin film for forming the emitter region is sufficiently formed by the step of etching the mask material and the second thin film. It is a material having a high etching resistance.

According to a thirty-seventh aspect of the present invention, in any one of the thirty-first to thirty-sixth aspects, the first opening is hexagonal.

The invention according to a thirty-eighth aspect is characterized in that, in the invention according to any one of the thirty-first to thirty-seventh aspects, the mask material is glass.

According to a thirty-ninth aspect of the present invention, in the thirty-first aspect of the present invention, the insulating layer comprises:
It is characterized by being constituted by an oxide film of approximately 2 μm.

According to a fortieth aspect of the present invention, in any one of the thirty-first to thirty-ninth aspects, the gate electrode layer is made of molybdenum having a thickness of about 1 μm.

According to a forty-first aspect of the present invention, there is provided a flat panel image display device comprising an electron emission source and a phosphor layer provided opposite to the electron emission source in a vacuum envelope, wherein the conductive layer provided on the substrate is provided. An insulating layer provided on the upper surface of the conductive layer; a gate electrode layer provided on the upper surface of the insulating layer; a thin film for forming the emitter region provided on the upper surface of the gate electrode layer; and a thin film for forming the emitter region A first opening formed by etching, a plurality of mask members densely arranged on a plane in the first opening, and a gap between the plurality of arranged mask members. A second opening formed by etching the gate electrode layer and the insulating layer in the first opening; and an emitter tip which is formed by depositing an emitter material from above the substrate and sharpened in the second opening. After depositing the emitter material, besides the emitter tip Characterized in that it is configured with a field emission cathode which is formed by removing by etching the thin film for a product with emitter material mask material and the emitter region formation.

The invention according to claim 42 is characterized in that, in the invention according to claim 41, the mask material is spherical.

According to the invention of claim 43, in the invention of claim 41 or 42, the plurality of mask members densely arranged on a plane are arranged while applying vibration while tilting the substrate. Features.

According to a forty-fourth aspect of the present invention, in the invention of any one of the forty-one to thirty-fourth aspects, the thickness of the thin film for forming the emitter region is defined as follows: The film thickness is not less than 3R and not more than 3R.

According to a forty-fifth aspect of the present invention, in any one of the forty-seventh to forty-fourth aspects, the thin film for forming the emitter region is an oxide film.

The invention according to claim 46 is the invention according to any one of claims 41 to 45, characterized in that the first opening is hexagonal.

A forty-seventh aspect of the present invention is characterized in that, in the invention of any one of the forty-first to forty-sixth aspects, the mask material is glass.

According to a forty-eighth aspect of the present invention, in the ninth aspect of the present invention, the insulating layer comprises:
It is characterized by being constituted by an oxide film of approximately 2 μm.

A forty-ninth aspect of the present invention is characterized in that, in any one of the forty-ninth to forty-ninth aspects, the gate electrode layer is made of molybdenum of about 1 μm.

According to a fifty aspect of the present invention, there is provided a flat panel image display device having an electron emission source and a phosphor layer provided facing the electron emission source in a vacuum envelope, wherein the conductive layer provided on the substrate is provided. An insulating layer provided on the upper surface of the conductive layer; a gate electrode layer provided on the upper surface of the insulating layer; a first thin film for forming an emitter region provided on the upper surface of the gate electrode layer; A second layer for forming an emitter region provided on the upper surface of the thin film;
And a first thin film and a second thin film for forming an emitter region.
A first opening formed by etching the thin film of the first, a plurality of mask materials densely arranged on a plane in the first opening, and a gap between the plurality of arranged mask materials. A second opening formed by etching the gate electrode layer and the insulating layer in the first opening, and a sharpened emitter tip in the second opening by depositing an emitter material from above the substrate. And a field emission type cold cathode formed by removing the emitter material deposited on the portion other than the emitter tip after the deposition of the emitter material by etching the second thin film.

The invention according to claim 51 is characterized in that, in the invention according to claim 50, the mask material is spherical.

The invention according to claim 52 is the invention according to claim 50 or 51, wherein the first for forming the emitter region is provided.
When the radius of the mask material is R, the film thickness obtained by adding the thin film and the second thin film is not less than R and not more than 3R.

The invention according to claim 53 is the invention according to any one of claims 50 to 52, wherein the plurality of mask members densely arranged on a plane apply vibration by tilting the substrate. While arranging the mask material, it is characterized.

The invention according to claim 54 is characterized in that, in the invention according to any one of claims 50 to 53, the second thin film for forming the emitter region is an oxide film.

According to a fifty-fifth aspect of the present invention, in the invention according to any one of the fifty to fifty-fourth aspects, the first thin film for forming the emitter region can be sufficiently etched by the step of etching the mask material and the second thin film. It is a material having a high etching resistance.

The invention according to claim 56 is the invention according to any one of claims 50 to 55, characterized in that the first opening is hexagonal.

The invention according to claim 57 is characterized in that, in the invention according to any one of claims 50 to 56, the mask material is glass.

According to a fifty-eighth aspect of the present invention, the insulating layer according to any one of the fifty to fifty-seventh aspects,
It is characterized by being constituted by an oxide film of approximately 2 μm.

The invention according to claim 59 is characterized in that, in the invention according to any one of claims 50 to 58, the gate electrode layer is made of molybdenum of approximately 1 μm.

[0075]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, a method for forming a fine opening, a field emission type cold cathode and a method for manufacturing the same according to an embodiment of the present invention, and a planar image using the field emission type cold cathode will be described. The device will be described in detail. FIG. 1 to FIG. 4 show an embodiment of a method for forming a fine opening, a field emission type cold cathode and a method for manufacturing the same, and a planar image device using the field emission type cold cathode according to the present invention.

FIG. 1 is a view showing a manufacturing process of a field emission type cold cathode using the method of forming a minute opening according to the first embodiment of the present invention. In this case, the right diagram is a schematic diagram showing a case where the dotted line portion shown in the left diagram is viewed from the cross section.

In FIG. 1F, on a glass substrate 1,
A conductive layer 2 of polysilicon or the like is deposited, and an insulating layer 3 of an oxide film of about 2 μm, a gate electrode layer 4 of 1 μm of molybdenum as a refractory metal, and an oxide film 5 of 10 μm are sequentially deposited. After that, the oxide film 5 is removed as shown in FIG.
As shown in FIG. 2, the film is etched into a hexagonal shape to form an emitter formation region 14.

Next, as shown in FIG. 1 (g), the emitter forming region 1 in which the oxide film 5 has been etched into a hexagonal shape.
4, a spherical mask material 6 made of glass having a diameter of 10 μm is arranged so as to be closest packed. The material of the mask material 6 may be silicon nitride, alumina, nylon, Teflon, or metal, but in this embodiment, a glass sphere which is relatively inexpensive and is the same material as the oxide film 5 described later is used. Be composed.

Although a spherical mask material is used here, the shape is not particularly limited.
For example, it is also possible to combine a cylinder, an oval sphere, a polygonal pillar, or a mask material of these different shapes.

In the hexagonal emitter forming region 14 in which the spherical mask material 6 is closest packed, a fine gap smaller than the radius of the mask material 6 when viewed from above is formed. FIG. 1B shows a case where a hexagonal emitter forming region 14 in which seven mask materials 6 can be arranged is formed. In this case, twelve gaps are formed in a self-aligned manner. .

The emitter forming region 14 can be formed by a polygon such as a triangle or a quadrangle.
Hexagons are suitable from the viewpoint that more mask materials can be regularly arranged in the same area and an emitter region with good symmetry is formed. When arranging the mask materials, vibration is applied while tilting the glass substrate 1 so that a close-packed structure of only one layer can be easily obtained. The thickness of the oxide film 5 is set to be equal to the radius of the mask material so that the mask material of the second layer or more is not laminated.
Then, it is necessary to set it to R or more and 3R or less. When arranging the mask material, a gas such as dry air or nitrogen may be blown.

If the mask material of the second layer or more is deposited, it is also possible to remove them by using an adhesive sheet or the like having high surface accuracy. Furthermore, the radius is 100 μm
In the case where the following mask material is used, it is necessary to remove static electricity before arrangement, and take care not to stack the mask material of the second layer or more.

Next, as shown in FIG. 1C, when the gate electrode layer 4 and the insulating layer 3 are anisotropically etched using the mask material 6 as a mask, the gap between the mask materials 6 is projected. A fine gate opening is formed. After that, molybdenum of the emitter material 7 is deposited from just above the glass substrate 1. As the deposition of molybdenum progresses, as shown in FIG. 1 (i), molybdenum also condenses around the side surfaces of the mask material 6,
As the deposited film thickness increases, the opening gradually decreases, and as shown in FIG. 1D, the opening is finally closed, and at the same time, the emitter 8 having a sharp tip is formed. Here, the mask material 6 plays the same role as the sacrificial layer shown in the prior art.

Finally, as shown in FIG. 1 (j),
By etching the oxide film 5 and the mask material 6 with hydrofluoric acid, excess emitter material 7 deposited on the upper layer is removed. At that time, hydrofluoric acid slightly penetrates also into the gate opening, so that the opening of the insulating layer 3 has a shape that is wider on the gate electrode layer 4 side than on the bottom. Such a shape increases the distance between the gate electrode layer 4 and the conductive layer 2 in the opening, and can improve the withstand voltage between the gate electrode layer 4 and the conductive layer 2.

This structure is similar to that shown in FIG.
The shape is the same as the shape obtained in the step (c), and in the embodiment of the present invention, this structure can be formed simultaneously in the step of removing the emitter material 7. The same material made of silicon dioxide is used for the mask material 6 and the thin film for the emitter formation region 14, that is, the oxide film 5 in order to reduce the number of steps, but different materials may be used. However, in that case, when the extra emitter material 7 deposited on the upper layer is removed, each material must be individually etched, so that the number of steps increases.

The amount of emission current depends on the radius of the mask material 6 and the size of the emitter formation region 14, that is, the emitter formation region 1.
4 depends on the number of mask materials 6 to be filled. In FIG. 1, assuming that the radius of the mask material is R and the number of mask materials arranged on one side of the hexagon is n, one side of the hexagon is 2R (n−0.423), The total number is 3n (n-1) +1, and the number of formed emitters is 6n (n-1). Here, n is an integer of 2 or more. From these relations, when the emission current per emitter is defined, it is possible to design a device for obtaining a necessary emission current.

FIG. 2 is an enlarged view of the gate opening and the emitter according to the embodiment of the present invention. As shown in FIG. 2A, a region surrounded by the three mask materials 6 corresponds to a gate opening, which simultaneously shows the shape of the emitter 8 as viewed from above. The center of gravity of a triangle formed by connecting the centers of the respective mask members 6, that is, the distance between the tip end position of the emitter 8 and the gate opening located closest to each other, is geometrically about R when the radius of the mask member 6 is R. 0.155R. The smaller the distance, the greater the concentration of the electric field at the tip of the emitter 8, so the amount of emission current increases. Therefore, as the radius R of the mask material 6 is smaller, the emission current characteristics are improved.

For example, when the mask material (R = 5 μm) having a diameter of 10 μm shown in the first embodiment of the present invention is used, the distance becomes 0.78 μm. This distance is about the same as the case of the gate opening diameter of 1.5 μm (the radius of 0.75 μm) shown in the conventional example, and the degree of electric field concentration at the tip of the emitter 8 that determines the amount of emission current is the same.

Therefore, according to the present invention, equivalent emission current characteristics can be realized only by using the arrangement of the mask materials without using a fine lithography technique or a sacrificial layer. In addition, since the emitter shape is determined in a self-aligned manner by the arrangement of the mask material, variation in the shape is small and uniform emission current characteristics can be obtained.

FIG. 2B is a view of the emitter 8 viewed from above, and FIG. 2C is a view of the emitter 8 viewed obliquely from above. The height of the emitter 8 depends on the method of depositing the emitter material, the directivity of the deposited particles,
Although it depends on the substrate temperature, it is desirable to control at least the tip of the emitter to be located within the thickness of the gate electrode layer 4 in order to increase the electric field concentration. In the vapor deposition apparatus and conditions in this embodiment, the tip of the emitter 8 is located at the center of the thickness of the gate electrode layer by setting the thickness of the insulating layer 3 to 2 μm and the thickness of the gate electrode layer 4 to 1 μm. Make sure that.

FIG. 3 is a view showing a manufacturing process of a field emission type cold cathode using the method of forming a fine opening according to the second embodiment of the present invention. In this case, the right diagram is a schematic diagram showing a case where the dotted line portion shown in the left diagram is viewed from the cross section.

The method of forming the emitter is basically the same as that shown in FIG. However, the emitter formation region 14
Are different in that two layers are used and an insulating layer is left on the gate electrode layer 4. As shown in FIG. 3 (f), a conductive layer 2 made of polysilicon or the like is deposited on a glass substrate 1 and an insulating layer 3 made of a 2 μm oxide film and 1 μm
m, a gate electrode layer 4 of molybdenum which is a high melting point metal, a nitride film 11 of 10 μm, and an oxide film 5 of 0.1 μm.
Are sequentially deposited. After that, the nitride film 11 and the oxide film 5 are etched in a hexagonal shape to form an emitter formation region 14.

Next, as shown in FIG. 3 (g), a spherical mask material 6 having a diameter of 10 μm is arranged in the opening of the emitter forming region 14 so as to be tightly packed by one layer. A minute gap is formed between adjacent mask members in a self-aligned manner.

Next, as shown in FIG. 3H, when the gate electrode layer 4 and the insulating layer 3 are anisotropically etched using the mask material 6 as a mask, the gap between the mask materials 6 is projected. A fine gate opening is formed. After that, molybdenum of the emitter material 7 is deposited from just above the glass substrate 1.

As the deposition of molybdenum proceeds, FIG.
As shown in (i), molybdenum also condenses around the side surface of the mask material 6, the thickness gradually increases and the opening gradually decreases, and the opening is finally closed. Is formed.

Finally, by etching the oxide film 5 and the mask material 6 with hydrofluoric acid, the excess emitter material 7 deposited on the upper layer is removed, and the emitter formation region 14 is surrounded on the gate electrode layer 4. Thus, the nitride film 11 remains.

As described in the first embodiment of the present invention,
The mask material 6 does not necessarily need to be glass, but it is desirable that the mask material 6 and the oxide film 5 be formed of the same material in order to simplify the manufacturing process. Further, the nitride film 11 does not necessarily need to be a nitride film, and
Any material may be used as long as it has sufficient etching resistance in the etching step of oxide film 5.

FIG. 4 is a cross-sectional view showing a configuration in the case where the field emission cold cathode formed by the above-described method is used as an electron source of a flat panel image device.

In FIG. 4, a conductive layer 2 is formed on a glass substrate 1.
Is formed, and a plurality of emitters 8 corresponding to each pixel are formed by the above-described method. At positions facing the emitter 8, R (red), G (green), B
The (blue) phosphors 10 are two-dimensionally regularly arranged via the transparent electrode 9. Since the distance between the adjacent spacers formed by the nitride film 11 is better for each pixel, it is better to arrange them regularly for each pixel. The inside of the planar image device is kept in a vacuum, and the electrons emitted from the emitter 8 collide with desired emitted electrons to a desired phosphor 10 arranged at a position facing the emitter 8 to obtain an image.

Since the inside of the device is kept in a vacuum, the gap (distance in the device) between the emitter 8 and the phosphor 10 is
A nitride film 1 for each pixel so that it is not compressed by atmospheric pressure
The spacer is provided immediately before the two glass substrates 1, 1 'on which the emitter 8 and the phosphor 10 are formed, independently of the emitter forming step. Do.

As shown in the first embodiment of the present invention, emitter regions are two-dimensionally arranged at positions corresponding to respective pixels. However, in the field emission cold cathode described in the second embodiment of the present invention, since the nitride film 11 is formed so as to surround the emitter formation region 14, it can also serve as a spacer.

Therefore, the spacer is arranged for each pixel, and the distance between the emitter 8 and the phosphor 10 can be made uniform in the device. Further, the step of installing the spacer after the formation of the emitter 8 is simplified. The thickness of the nitride film 11, that is, the length of the spacer is substantially equal to the radius of the mask material 6. As described above, the amount of emission current depends on the radius and the number of the mask material, that is, the size of the emitter forming region 14. For example, in order to lengthen the spacer, the radius of the mask material is increased and the region is enlarged. There is a need. By arranging the spacers in each pixel in this manner, the distance between the emitter and the phosphor, that is, the potential between the two electrodes becomes uniform in a plane, and the unevenness of the image due to the unevenness of the emission current is reduced. Is done.

[0103]

As is apparent from the above description, according to the present invention, the etching of the gate electrode layer and the insulating layer and the formation of the emitter are carried out by utilizing the gap between the adjacent mask materials, so that the problems of the prior art are problematic. It is possible to manufacture an emitter and a planar image device without using a fine lithography technique and a sacrificial layer.

Further, according to the present invention, by forming two layers of the thin film for forming the emitter region, it is possible to simultaneously form a spacer for installing a counter electrode such as a phosphor. Accordingly, an improvement in throughput and a reduction in cost can be realized, and a large-screen flat image device with high uniformity can be manufactured.

[Brief description of the drawings]

FIG. 1 is a structural view showing a manufacturing process of a field emission cold cathode according to a first embodiment of the present invention.

FIG. 2 is a structural diagram of a gate opening and an emitter according to the embodiment of the present invention.

FIG. 3 is a structural view showing a manufacturing process of a field emission cold cathode according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional structural view of the flat panel image device according to the embodiment of the present invention.

FIG. 5 is a structural view showing a manufacturing process of a field emission cold cathode according to the prior art.

FIG. 6 is a cross-sectional structural view of a planar image device according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Conductive layer 3 Insulating layer 4 Gate electrode layer 5 Oxide film 6 Mask material 7 Emitter material 8 Emitter 9 Transparent electrode 10 Phosphor 11 Nitride film (spacer) 14 Emitter formation area

Claims (59)

[Claims] 1. A step of densely arranging a plurality of mask members in a planar manner on a region to be etched, and utilizing a gap between adjacent mask members of the arranged plurality of mask members. Forming a micro-aperture by etching the micro-aperture. 2. The method according to claim 1, wherein the mask material has a spherical shape. 3. The micro-aperture according to claim 1, wherein the step of densely arranging the plurality of mask members on a plane includes arranging the conductive substrate while tilting and applying vibration. Formation method. 4. The method according to claim 1, wherein the mask material is glass. 5. A conductive layer provided on a substrate, an insulating layer provided on an upper surface of the conductive layer, a gate electrode layer provided on an upper surface of the insulating layer, and provided on an upper surface of the gate electrode layer. A thin film for forming an emitter region, a first opening formed by etching the thin film for forming an emitter region, and a plurality of masks densely arranged on a plane in the first opening. A second opening formed by etching the gate electrode layer and the insulating layer in the first opening using gaps between the plurality of mask materials arranged; A sharpened emitter tip in the second opening by depositing an emitter material from the substrate, and depositing the emitter material other than the emitter tip after depositing the emitter material for forming the mask material and the emitter region. Thin The field emission cathode, characterized in that it is formed are removed by etching. 6. The field emission cold cathode according to claim 5, wherein said mask material is spherical. 7. The field emission cooling device according to claim 5, wherein the plurality of mask members densely arranged on the plane are arranged while applying vibration while tilting the substrate. cathode. 8. The film thickness of the thin film for forming an emitter region is, when the radius of the mask material is R, not less than R and not more than 3R.
The field emission cold cathode according to any one of claims 5 to 7, wherein the thickness is as follows. 9. The semiconductor device according to claim 5, wherein the thin film for forming the emitter region is an oxide film.
Item 1. A field emission cold cathode according to item 1. 10. The field emission cold cathode according to claim 5, wherein the first opening has a hexagonal shape. 11. The semiconductor device according to claim 5, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
The field emission cold cathode according to any one of the above items. 12. The field emission cold cathode according to claim 5, wherein the gate electrode layer is made of molybdenum having a thickness of about 1 μm. 13. A conductive layer provided on a substrate, an insulating layer provided on an upper surface of the conductive layer, a gate electrode layer provided on an upper surface of the insulating layer, and provided on an upper surface of the gate electrode layer. A first thin film for forming an emitter region, a second thin film for forming an emitter region provided on an upper surface of the first thin film, the first thin film for forming the emitter region, and the second thin film. A first opening formed by etching a thin film of a plurality of masks; a plurality of masks densely arranged on a plane in the first opening; and a gap between the plurality of masks arranged. A second opening formed by etching the gate electrode layer and the insulating layer in the first opening, and an emitter material deposited on the substrate to be sharpened in the second opening. The emitter material. A field emission cold cathode formed by removing an emitter material deposited on a portion other than the emitter tip after depositing a material by etching the mask material and the second thin film. 14. The field emission cold cathode according to claim 13, wherein said mask material is spherical. 15. The electric field according to claim 13, wherein the plurality of mask members densely arranged on the plane arrange the mask members while applying vibration while tilting the substrate. Emission cold cathode. 16. The total thickness of the first thin film and the second thin film for forming the emitter region is equal to or more than R and equal to or less than 3R when the radius of the mask material is R. The field emission cold cathode according to any one of claims 13 to 15, wherein: 17. The field emission cold cathode according to claim 13, wherein the second thin film for forming the emitter region is an oxide film. 18. The semiconductor device according to claim 13, wherein said first thin film for forming said emitter region is a material having sufficient etching resistance in an etching step of said mask material and said second thin film. The field emission cold cathode according to any one of the above items. 19. The field emission cold cathode according to claim 13, wherein the first opening has a hexagonal shape. 20. The field emission cold cathode according to claim 13, wherein the mask material is glass. 21. The semiconductor device according to claim 13, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
0. The field emission type cold cathode according to any one of 0. 22. The field emission cold cathode according to claim 13, wherein the gate electrode layer is made of molybdenum having a thickness of about 1 μm. 23. A step of forming a conductive layer on a substrate; a step of forming an insulating layer on the upper surface of the conductive layer; a step of forming a gate electrode layer on the upper surface of the insulating layer; Forming a thin film for forming an emitter region on the upper surface; forming a first opening by etching the thin film for forming the emitter region; and forming a plurality of mask materials in the first opening. A step of densely arranging the gate electrode layer and the insulating layer in the first opening using a gap between the arranged mask materials;
Forming an opening in the second opening; and forming a sharpened emitter tip in the second opening by depositing an emitter material from above the substrate; and depositing the emitter material on a portion other than the emitter tip after depositing the emitter material. Removing the emitter material by etching the mask material and the thin film for forming the emitter region. 24. The method according to claim 23, wherein the mask material is spherical. 25. The field emission cooling device according to claim 23, wherein in the step of densely arranging the plurality of mask members on a plane, the substrate is arranged while tilting and applying vibration. Manufacturing method of cathode. 26. A film thickness of the thin film for forming an emitter region is, when the radius of the mask material is R, not less than R and not more than 3R.
The film thickness is as follows:
The method for producing a field emission cold cathode according to any one of the above items. 27. The method according to claim 23, wherein the thin film for forming the emitter region is an oxide film. 28. The method according to claim 23, wherein the first opening has a hexagonal shape. 29. The semiconductor device according to claim 23, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
9. The method for producing a field emission cold cathode according to any one of items 8 to 9. 30. The method according to claim 23, wherein the gate electrode layer is made of molybdenum having a thickness of about 1 μm. 31. A step of forming a conductive layer on a substrate; a step of forming an insulating layer on an upper surface of the conductive layer; a step of forming a gate electrode layer on an upper surface of the insulating layer; Forming a first thin film for forming an emitter region on an upper surface; forming a second thin film for forming an emitter region on an upper surface of the first thin film; and forming the first thin film for forming the emitter region. A step of forming a first opening by etching the thin film and the second thin film; a step of densely arranging a plurality of mask materials on a plane in the first opening; Forming a second opening by etching the gate electrode layer and the insulating layer in the first opening using the gap of the mask material, and depositing an emitter material on the substrate to form a second opening. Emitter tip sharpened in opening Forming a mask, and removing, by etching, only the second thin film of the mask material and the thin film for forming the emitter region from the emitter material deposited on the portion other than the emitter tip after the deposition of the emitter material. A method for producing a field emission cold cathode, comprising: 32. The method according to claim 31, wherein the mask material is spherical. 33. The method according to claim 3, wherein the step of densely arranging the plurality of mask members on a plane includes arranging the mask members while applying vibration while tilting the substrate.
33. The method for producing a field emission cold cathode according to 1 or 32. 34. A film thickness obtained by adding the first thin film and the second thin film for forming the emitter region, where R is the radius of the mask material and is 3R or less. The method for producing a field emission cold cathode according to any one of claims 31 to 33, characterized in that: 35. The method according to claim 31, wherein the second thin film for forming the emitter region is an oxide film. 36. The method according to claim 31, wherein the first thin film for forming the emitter region is made of a material having a sufficient etching resistance in an etching step of the mask material and the second thin film. The method for producing a field emission cold cathode according to any one of the above items. 37. The method according to claim 31, wherein the first opening has a hexagonal shape. 38. The method according to claim 31, wherein the mask material is glass. 39. The semiconductor device according to claim 31, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
9. The method for producing a field emission cold cathode according to any one of items 8 to 9. 40. The method according to claim 31, wherein the gate electrode layer is made of molybdenum having a thickness of about 1 μm. 41. A planar image device comprising an electron emission source in a vacuum envelope and a phosphor layer provided opposite to the electron emission source, comprising: a conductive layer provided on a substrate; An insulating layer provided on the upper surface, a gate electrode layer provided on the upper surface of the insulating layer, a thin film for forming an emitter region provided on the upper surface of the gate electrode layer, and a thin film for forming the emitter region are etched. A first opening formed by
A plurality of mask materials densely arranged on a plane in the opening, and a gate electrode layer and the insulating layer in the first opening using a gap between the arranged plurality of mask materials. A second opening formed by etching; and an emitter tip which is formed by depositing an emitter material from above the substrate and which is sharpened in the second opening, and other than the emitter tip after depositing the emitter material. A field emission type cold cathode formed by removing an emitter material deposited on a mask material and a thin film for forming the emitter region by etching. 42. A flat image apparatus according to claim 41, wherein said mask material is spherical. 43. The flat image apparatus according to claim 41, wherein the plurality of mask members densely arranged on the plane are arranged while applying vibration while tilting the substrate. 44. The film thickness of the thin film for forming the emitter region is, when the radius of the mask material is R, not less than R and not more than 3R.
44. The film thickness is as follows.
The planar image device according to any one of the above items. 45. The planar image device according to claim 41, wherein the thin film for forming the emitter region is an oxide film. 46. The apparatus according to claim 41, wherein the first opening has a hexagonal shape. 47. A flat image apparatus according to claim 41, wherein said mask material is glass. 48. The semiconductor device according to claim 41, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
8. The planar image device according to any one of items 7 to 7. 49. The planar image device according to claim 41, wherein the gate electrode layer is made of molybdenum of about 1 μm. 50. A planar image device comprising an electron emission source in a vacuum envelope and a phosphor layer provided to face the electron emission source, comprising: a conductive layer provided on a substrate; An insulating layer provided on the upper surface; a gate electrode layer provided on the upper surface of the insulating layer; a first thin film for forming an emitter region provided on the upper surface of the gate electrode layer; A second thin film provided on an upper surface for forming an emitter region; a first opening formed by etching the first thin film and the second thin film for forming the emitter region; Etching the gate electrode layer and the insulating layer in the first opening using a plurality of mask materials densely arranged on a plane in the opening and using a gap between the plurality of arranged masking materials; And a second opening formed on the substrate. A sharpened emitter tip in the second opening by depositing a mitter material, and etching the mask material and the second thin film with the emitter material deposited on the portion other than the emitter tip after depositing the emitter material. A flat image device comprising a field emission type cold cathode formed by being removed by the method. 51. A flat image apparatus according to claim 50, wherein said mask material is spherical. 52. A film thickness obtained by adding the first thin film and the second thin film for forming the emitter region is equal to or more than R and equal to or less than 3R when the radius of the mask material is R. The planar image device according to claim 50 or 51, wherein: 53. The mask material according to claim 50, wherein the plurality of mask materials densely arranged on the plane are arranged while tilting the substrate and applying vibration. Item 2. The planar image device according to item 1. 54. The planar image device according to claim 50, wherein the second thin film for forming the emitter region is an oxide film. 55. The method according to claim 50, wherein the first thin film for forming the emitter region is a material having sufficient etching resistance in an etching step of the mask material and the second thin film. The planar image device according to any one of the above items. 56. The planar image device according to claim 50, wherein the first opening has a hexagonal shape. 57. The planar image device according to claim 50, wherein the mask material is glass. 58. The semiconductor device according to claim 50, wherein the insulating layer is formed of an oxide film having a thickness of about 2 μm.
8. The planar image device according to any one of items 7 to 7. 59. The planar image device according to claim 50, wherein the gate electrode layer is made of molybdenum having a thickness of about 1 μm.