JPH05225895A - Manufacture of electric-field emission cathode electrode - Google Patents

Abstract

PURPOSE:To provide a production method for electric-field emission cathode electrode enabling easy and inexpensive procurement of an electric-field emission metal cathode electrode having sufficient electric performance and reliability. CONSTITUTION:A reversed pyramid shape recess 14 is formed in a silicon substrate 11 by etching. After an electric-field emission cathode electrode material 16 is formed thereon, the silicon substrate 11 is removed by etching, by which an electric-field emission cathode electrode 17 is formed integrally with the electric-field emission cathode electrode material 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a field emission cathode in a micro vacuum device.

[0002]

2. Description of the Related Art Recently, attempts have been made to form ultra-high-speed vacuum integrated circuits and high-definition flat panel cathode ray tubes by using minute field emission cathodes. These micro vacuum devices are formed by using a semiconductor microfabrication technology, and aim at high functionality and high integration of elements.

The field emission cathode is a main constituent element of a micro vacuum device, and can be classified into two types, a cone shape and a wedge shape, depending on its shape. The cone-shaped field emission cathode emits electrons in a direction vertical to the substrate, and the wedge type emits electrons in a horizontal direction. The conical field emission cathode can be divided into two types, a vapor deposition type and an etching type, depending on the forming method. In the vapor deposition type, the cathode is formed by vapor deposition of metal, and the etching type is formed by anisotropic etching of silicon. The wedge shape is formed by vapor deposition of metal and its etching.

A flat panel CRT is a device to which these field emission cathodes are applied. Flat panel CRTs seek to maximize the high integration of field emission cathodes.

FIG. 6 is a sectional view showing a conventional cone-shaped field emission cathode. In the figure, 61 is a substrate and 62 is an insulating film 6.
A gate electrode film provided on the substrate 61 via
Is a field emission cathode (emitter cone) projected on the substrate 61 and is formed in a cone shape or a pyramid shape. The gate electrode film 62 is formed on a silicon oxide insulating film 63. Field emission cathode 64 and anode (not shown)
An electron is extracted from the tip of the field emission cathode 64 by applying a voltage between the emitter and the gate and applying a voltage between the emitter and the gate. The radius of curvature of the tip of the field emission cathode 64 is several hundred Å.

FIG. 7 is a manufacturing process chart showing a method of manufacturing a vapor deposition type field emission cathode. In the drawing, 72 is an insulating film of silicon oxide (Si O ₂ ) formed on a substrate 71, and 73 is molybdenum. A film, 74 is an aluminum sacrificial layer, 75 is a molybdenum deposited film, and 76 is a field emission cathode.

First, in FIG. 7, an insulating film 72 having a thickness of 1 to 1.5 μm is formed on a substrate 71 of a silicon wafer which has been surface-doped to improve its conductivity.
3 is electron beam evaporated. From this, the molybdenum film 73 and the insulating film 72 are removed by etching into a circular shape having a diameter of 1 μm. Next, silicon oxide is slightly melted with hydrofluoric acid, and then the aluminum sacrificial layer 74 is vapor-deposited from an oblique direction as shown in FIG. Next, molybdenum is vacuum-deposited from above. This molybdenum vapor deposition film 75 is made of aluminum, molybdenum, and silicon oxide films 74, 73,
Although it is deposited on the substrate 71 through the hole 72, it is also deposited on the edge of the hole of the molybdenum vapor deposition film 75, so that the diameter of the hole is gradually reduced and finally the hole is closed. for that reason,
Molybdenum has a cone shape and is formed on the substrate 71 as shown in FIG.
Deposit as shown in. Finally aluminum sacrificial layer 74
By dissolving and removing the molybdenum film 73 on the surface at the same time as shown in FIG. 7C, the desired field emission cathode 76 is obtained.

FIG. 8 shows a method of forming an etching type field emission cathode. In the figure, 81 is a substrate, and 82 is a substrate 81.
An etching mask placed on top, 83 an insulating film, 84 a gate electrode, and 85 a field emission cathode.

According to FIG. 8, in order to increase the conductivity,
Doping phosphorus on the surface of the substrate 81 of the silicon wafer in advance, and
Leave it as a silicon. On top of that, silicon nitride (Si ₃ N ₄
) Or silicon oxide (SiO ₂ ) etching mask 82
To a desired size (circle of 1 to 2 μm), and
Place as shown in (a). Next, when the silicon wafer is anisotropically etched with a solution such as potassium hydroxide (KOH), the silicon is processed into a pyramid shape as shown in FIG. 8B. The radius of curvature of the tip of this pyramid is less than 1000Å. Then, an insulating film (1) of silicon oxide is formed around the field emission cathode 85 thus formed.
˜2 μm thickness, CVD method) 83 and metal film for gate (0.5 μm thickness, tungsten, molybdenum, tantalum, etc.)
EB vapor deposition method) 84 is formed as shown in FIG.

[0010]

Since the conventional method for producing a field emission cathode is as described above, in the method for forming a vapor deposition type field emission cathode, since the field emission cathode 76 is made of metal, a high current is generated. Although it has an advantage that the density can be expected, since the metal is vapor-deposited through a small opening of micron order, the field emission cathode 7 is formed depending on the size of the diameter of the opening.
There is a problem that the diameter and height of 6 are different and it is difficult to control the shape. In addition, as such a conventional manufacturing method, a display magazine {(Technical not
e, DISPLAYS) Technical Note, issued January 1987}.

Further, in the method of forming the etching type field emission cathode, since the field emission cathode is formed by utilizing anisotropic etching of silicon, it is relatively easy to control the shape, but silicon itself has an electrode structure. Since it is a material, there are problems that the current density is low and the current-voltage characteristics are irregular.

When the gate electrode 84 is formed, the gate electrode material is formed on the entire surface of the substrate by the above method. In this case, in order to introduce an image signal, the gate electrode material or the field emission cathode is used. Although it is necessary to pattern the material, this patterning requires additional steps such as photoengraving and etching.
After the formation of 6,85 cones, there was a problem that the tip of the cone might be adversely affected.

Further, when the field emission cathode is constructed by using the vapor deposition method or the etching method as described above, a substrate having conductivity or a substrate is used to make an electrical connection to the cathode cone. There was a problem that additional processing such as drilling a terminal hole for connection was required.

Furthermore, a large area flat panel CR
In order to configure T, a unit of a certain size in which the field emission cathode is configured must be tiled vertically and horizontally, and in this case, in order to prevent the connection portion of each unit from widening, Although it is desirable to take the electrode connected to each unit from the back surface of the unit rather than from the side surface, there is a problem that it is difficult to take the electrode from the back surface in the above configuration.

The invention of claim 1 is to solve the above-mentioned problems, and by using a field emission cathode made of metal, a high current density and a pyramidal shape are obtained. Therefore, an object of the present invention is to obtain a method of manufacturing a field emission cathode having high performance and reliability and low manufacturing cost by adopting a relatively easy shape control method.

According to the invention of claim 2, the gate electrode is patterned before forming the cone of the field emission cathode to obtain a method of manufacturing the field emission cathode capable of preventing damage to the tip of the cone due to post-processing. To aim.

Further, an object of the invention of claim 3 is to obtain a method for producing a field emission cathode by taking out the terminal of the gate electrode from the back surface, thereby making it possible to reduce the gap of the joint portion when tiling. ..

Furthermore, the invention of claim 4 is XY
It is an object of the present invention to obtain a method for manufacturing a field emission cathode capable of simultaneously forming a gate electrode having a matrix pattern.

[0019]

According to the method of manufacturing a field emission cathode according to the invention of claim 1, a photoresist is applied on an etching mask formed on a silicon substrate, and then photolithography is performed to obtain the above-mentioned silicon. After covering the other part of the base substrate with a resist and then dissolving and removing the etching mask in the above part, the pyramidal pits are formed by anisotropic etching with an aqueous solution of potassium hydroxide to form the pyramidal surface. Formed on the surface of the silicon substrate from which the photoresist and the etching mask have been removed, a field emission cathode material is formed so as to be filled in the recesses, and finally, the silicon substrate is removed by etching. A pyramidal field emission cathode is exposed on the field emission cathode material.

Further, in the method for manufacturing a field emission cathode according to the invention of claim 2, a photoresist is applied on an etching mask formed on a silicon substrate, a photoengraving process is performed, and a part of the etching mask is applied. Etching the others while leaving it, and further anisotropically etching the silicon substrate to a certain depth by reactive dry etching, and forming a gate electrode material and an insulating film to a predetermined thickness on it, The etching mask, the gate electrode material and the insulating film in a part are removed to expose the surface of the silicon substrate, and a conical recess is formed in this exposed portion by anisotropic etching with an aqueous solution of potassium hydroxide. Field emission cathode material is formed on the surfaces of the silicon substrate and the insulating film so that the silicon substrate is also filled in, and finally the silicon substrate is removed by etching. It is obtained by way.

Further, in the method for manufacturing a field emission cathode according to the invention of claim 3, a photoresist is applied on an etching mask formed on a silicon substrate, a photoengraving process is performed, and a part of the etching mask is removed. After etching the others, the silicon substrate is anisotropically etched to a certain depth by reactive dry etching, and a gate electrode material and an insulating film are formed to a predetermined thickness on the silicon substrate. The surface of the silicon substrate is exposed by removing the etching mask, the gate electrode material, and the insulating film in a part, and furthermore, a through hole is formed in the insulating film by etching, and potassium hydroxide is exposed on the exposed portion of the silicon substrate. A conical recess is formed by anisotropic etching with an aqueous solution. A method in which a field emission cathode material is formed on a silicon substrate and an insulating film, patterning is performed so that the field emission cathode material on the through hole is removed, and finally the silicon substrate is removed by etching. Is.

Further, in the method for producing a field emission cathode according to the invention of claim 4, a photoresist is applied on an etching mask formed on a silicon substrate, and then photolithography is performed to partially remove the etching mask. Etching the others leaving, and further anisotropically etching the silicon substrate to a certain depth by reactive dry etching,
After forming a gate electrode material and an insulating film to a predetermined thickness on it, an etching mask and a gate electrode material in the above part are formed to a predetermined thickness, and then a part of the surface of the gate electrode material is arbitrarily formed. Pattern is formed by photolithography, and then the etching mask is removed to expose the surface of the gate electrode material, and then an insulating film is formed to a predetermined thickness on the surface of the gate electrode material. , The gate electrode material and the insulating film are removed to expose the surface of the silicon substrate, a through hole is formed in the insulating film other than the above part by etching, and the exposed part of the silicon substrate is hydrated. A conical recess is formed by anisotropic etching with a potassium aqueous solution, and the silicon substrate and the recess are filled so as to fill the recess, the through hole, and the pattern. The field emission cathode material is formed on the border membrane performs patterning such as field emission cathode material on the through hole is removed is the last one so as to remove the silicon substrate by etching.

[0023]

The pyramidal depression provided on the silicon substrate according to the first aspect of the present invention is formed by forming a metal field emission cathode material on the upper surface of the silicon substrate including the depression to etch the substrate. By removing by means of, it is possible to form a cone-shaped field emission cathode having a high current density on the field emission cathode material without damage.

The gate electrode according to the second aspect of the present invention enables patterning on the silicon substrate which is removed in the final step in the process of forming the metal field emission cathode, and the tip of the cone is damaged. Make it possible to avoid an accident.

Further, the through hole according to the invention of claim 3 is filled with a field emission cathode material to form a terminal capable of taking out the gate electrode from the back surface,
Make it possible to keep the joint gap small when tiling.

The patterned gate electrode according to the invention of claim 4 is the X-type electrode in a flat panel CRT.
The Y matrix can be easily and quickly formed in the process of forming the field emission cathode.

[0027]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a method for forming a field emission cathode according to the present invention, in which 11 is a silicon substrate, 12 is an etching mask for etching the substrate,
13 is a photoresist, 14 is a conical recess formed on the silicon substrate 11, 16 is a field emission cathode material, and 17 is a field emission cathode.

First, as shown in FIG. 1A, a silicon oxide film having a thickness of 3000 Å is formed as an etching mask 12 on a silicon substrate (having a thickness of about 0.5 mm and a crystal orientation of 100). Note that a thermal silicon oxide film, a silicon nitride film, or the like may be used instead of the silicon oxide film thus formed. Further, after applying the photoresist 13 thereon, photoengraving is performed, and the portion other than the portion where the conical recess is provided on the substrate 11 is covered with the photoresist 13 as shown in FIG. 1B (first step). Then, a silicon oxide etching mask 12 is formed by using an aqueous solution of hydrofluoric acid or ammonium fluoride.
Are dissolved and removed as shown in FIG. Further, the substrate 11 is dipped in an aqueous solution of potassium hydroxide and anisotropically etched to form pyramidal depressions as shown in FIG. 1D on the surface of the silicon substrate 11 (second step). Finally,
After removing the photoresist 13, the etching mask 1
By removing the silicon oxide film of No. 2 by etching with hydrofluoric acid or the like, the silicon substrate 11 having the pyramidal recesses 14 is formed.
Can be obtained. Therefore, this silicon substrate 1
The field emission cathode material 16 is provided on the upper surface including the recess 14 of FIG.
As shown in (e), it is formed by a sputtering method or the like (3rd
Process) and wet-etching it to remove the silicon substrate 11, thereby forming the field emission cathode 17 on the field emission cathode material 16 as shown in FIG. 1F (fourth process). ..

In addition to hydrofluoric acid and nitric acid, alkaline etching solutions other than hydrofluoric acid and nitric acid,
If potassium hydroxide or an organic alkaline aqueous solution is heated, a considerable etching rate is reached. This type of etching solution has a large crystal orientation dependency, and the etching rate in the 100-direction crystal orientation as shown in FIG. 2 is fast, whereas the etching rate in the 111-direction in FIG. 2 is the slowest.

Therefore, when a silicon wafer having a crystal orientation of 100 planes is used as the silicon substrate 11 and the lines of the pattern are oriented in the 111 direction, the 111 plane including these lines appears. Since etching hardly progresses in this direction, the etching shape is as shown in FIG.

Example 2. FIG. 3 is a sectional view showing an embodiment of the invention of claim 2, in which 21 is a silicon substrate, 22 is an etching mask for etching the substrate, and 2 is an etching mask.
3 is a gate electrode material, 24 is an insulating film, 25 is a conical recess provided on the surface of the silicon substrate 21, 26 is a field emission cathode material (emitter cone material), and 27 is a formed field emission cathode (emitter). Corn).

Next, a method of forming the field emission cathode will be described. First, as an etching mask 22, chromium is sputtered to a thickness of 2000 Å on a silicon substrate (about 0.5 mm thickness, crystal orientation 100). Further, after applying a photoresist on it, photoengraving is performed, and 1.
Ion beam etching (IBE) is performed while leaving the 5 μm square etching mask 22 to form the etching mask 22 only in the portion where the cathode cone is formed, as shown in FIG. 3A (fifth step). Next, this silicon substrate 21 is placed in a reactive dry etching apparatus, and high frequency plasma of a mixed gas of tetrafluoromethane (CF ₄ ) and oxygen (O ₂ ) is used to obtain the structure shown in FIG. As shown, anisotropic etching is performed to a depth of 2 μm (sixth step).

Further, a gate electrode material 23 such as molybdenum, tungsten, or gold is formed to a thickness of 5000 Å by a sputtering method or a vacuum evaporation method, and silicon oxide is deposited thereon as shown in FIG. 3 (c). The insulating film 24 is formed to a thickness of 1.5 μm by a sputtering method or the like. Next, the etching mask 22, the gate electrode material 23, the insulating film 24 attached to the portion where the conical recess is formed on the surface of the silicon substrate 21.
Are removed to expose the surface of the silicon substrate 21 as shown in FIG. 3D (seventh step). Further, in the same manner as in Example 1, as shown in FIG. 3E, a conical recess 25 is formed in the exposed surface portion of the silicon substrate 21 by anisotropic etching by dipping a potassium hydroxide aqueous solution. (Step 8). At this time, in order to avoid etching the back surface of the silicon substrate 21, it is desirable to cover the back surface of the silicon substrate 21 with a mask material.

Next, a field emission cathode material 26 is formed on the surface of the silicon substrate 21 by a sputtering method or a vacuum deposition method,
Also in the conical recess 25 on the surface of the silicon substrate 21, FIG.
It is filled as shown in (f) (9th step). After that, the silicon substrate 21 is removed by wet etching using potassium hydroxide or reactive ion etching using tetrafluoromethane as shown in FIG. 3 (g) to expose the emitter cone 27 (tenth). Process).
The gate electrode, the insulating layer, and the field emission cathode can be formed by the above method. In this case, before removing the silicon substrate 21,
It is desirable to bond a support substrate supporting the field emission cathode to the surface of the silicon substrate 21.

Example 3. FIG. 4 is a sectional view showing an embodiment of the invention of claim 3, in which 31 is a silicon substrate, 32 is an etching mask for etching the substrate, and 3 is an etching mask.
3 is a gate electrode material, 34 is an insulating film, 35 is an insulating film 34
Through holes provided therein, 36 is a conical recess provided on the surface of the silicon substrate 31, 37 is a field emission cathode material (emitter cone material), 38 is an emitter cone material 3
7 is a through hole filled with 39, 39 is a pattern in which the emitter cone material 37 is patterned, and 40 is a field emission cathode as the formed emitter cone.

First, as an etching mask 32, chromium is sputtered to a thickness of 2000 Å on a silicon substrate (about 0.5 mm thick, crystal orientation 100). After applying a photoresist on it, photoengraving is performed, and then 1.5
Ion beam etching is performed while leaving the etching mask 32 of square μm, and as shown in FIG. 4A, the etching mask 32 is formed only in the portion where the cathode cone is formed.

Next, this silicon substrate 31 is placed in a reactive dry etching apparatus, and tetrafluoromethane (C
Using high frequency plasma of a mixed gas of F ₄ ) and oxygen (O ₂ ), anisotropic etching is performed to a depth of 2 μm as shown in FIG. 4B (11th step). Further, a gate electrode material 33 such as molybdenum, tungsten, or gold is formed to a thickness of 5000 Å by a sputtering method or a vacuum evaporation method, and a silicon oxide insulating film 34 is formed thereon as shown in FIG. 4C. It is formed to have a thickness of 1.5 μm by a sputtering method or the like (a twelfth step). Next, the etching mask 3 attached to the portion where the conical depression is formed on the surface of the silicon substrate 31.
2, the gate electrode material 33 and the insulating film 34 are removed, and FIG.
As shown in (d), the surface of the silicon substrate 31 is exposed (13th step).

After that, photolithography is performed, and wet etching is performed using an aqueous solution of hydrofluoric acid or ammonium fluoride or reactive ion etching is performed using tetrafluoromethane, as shown in FIG.
Through holes 35 are formed in the wiring 4 (14th step). Next, in the portion where the silicon is exposed as in Example 1,
A conical recess 36 as shown in FIG. 4F is formed.
At this time, in order to avoid etching of the back surface of the silicon substrate 31, it is desirable to cover the back surface of the substrate with a mask material.

Next, a field emission cathode material 37 as an emitter cone material is formed on the surface of the silicon substrate 31 by a sputtering method or a vacuum deposition method as shown in FIG. Surface conical depression 36 and insulating film 3
The through holes 35 in 4 are also filled (15th step). After that, the surface of the field emission cathode material 37 is subjected to photoengraving. At this time, the pattern 3 capable of removing the field emission cathode material 37 on the inside of the through hole 35 provided in the insulating film
Photoengraving is performed in 9 (16th step).

Further, the field emission cathode material 37 is etched by ion beam etching to expose the surface of the filled through hole 38. Then, the silicon substrate 3
1 is removed by wet etching using potassium hydroxide or reactive ion etching using tetrafluoromethane to expose the field emission cathode 40, which is an emitter cone, as shown in FIG. 4 (i) (step 17). ..

The field emission cathode material 37 shown in FIG.
When etching is carried out, it is not always necessary to use ion beam etching as long as it is a material capable of reactive etching by using plasma of tetrafluoromethane gas like molybdenum. The gate electrode, the insulating layer, and the field emission cathode can be formed by the above method.
In this case, before removing the silicon substrate 31, it is desirable to join a support substrate supporting the field emission cathode to the surface of the silicon substrate 31.

Further, in this embodiment, not only the field emission cathode material 37 but also the gate electrode can be exposed on the back surface of the formed field emission cathode 40 by the electrode material with which the through hole is filled. Therefore, it is not necessary to take an electrode for connection from the side surface of the silicon substrate 31, and when the silicon substrates 31 are tiled, the gap between the bonded portions between the silicon substrates 31 can be made narrower.

Example 4. 5 is a sectional view showing an embodiment of the invention of claim 4, in which 41 is a silicon substrate, 42 is an etching mask for etching the substrate, and 4 is an etching mask.
3 is a gate electrode material, 44 is a pattern obtained by patterning the gate electrode, 45 is an insulating film, 46 is a through hole provided in the insulating film 45, 47 is a conical recess provided on the surface of the substrate 41, and 48 is an emitter. A field emission cathode material as a cone material, 49 is a through hole filled with the field emission cathode material 48, 50 is a portion where the field emission cathode material is patterned, and 51 is a field emission cathode as an formed emitter cone.

Next, a method for forming the field emission cathode will be described. First, as an etching mask 42, chromium is sputtered to a thickness of 2000 Å on a silicon substrate (about 0.5 mm thick, crystal orientation 100). After applying a photoresist thereon, photoengraving is performed, and ion beam etching is performed while leaving a 1.5 μm square etching mask 42, and as shown in FIG. 5A, only a portion where a cathode cone is formed is etched. The mask 42 is formed.

Next, the silicon substrate 41 is set in a reactive dry etching apparatus, and the same high frequency plasma of a mixed gas of tetrafluoromethane and oxygen as described above is used,
As shown in FIG. 5B, anisotropic etching is performed to a depth of 2 μm (step 18). Further, the gate electrode material 43 as described above is formed by the sputtering method or the vacuum deposition method.
Is formed to a thickness of 5000Å as shown in FIG. 5C (19th step). Here, the surface of the gate electrode material 43 is photoengraved. At this time, as a pattern, an arbitrary pattern convenient for driving the field emission cathode is prepared. For example, since a flat display using a field emission cathode receives an image signal in an XY matrix,
The gate electrode is preferably a stripe pattern in the X direction or the Y direction. Then, the gate electrode material 43 is etched by ion beam etching or the like using an etching mask (not shown) to form a pattern 44 as shown in FIG. 5D (step 20).

Next, the etching mask (not shown) used when the pattern 44 is formed by etching is removed to expose the surface of the gate electrode material 43, and then an insulating film 45 of silicon oxide is sputtered thereon. Method, Fig. 5 (e)
As shown in FIG. 5, it is formed to a thickness of 1.5 μm (step 21). Next, on the portion where the conical depression is formed on the surface of the silicon substrate 41, that is, on the protruding portion of the silicon substrate 41 masked by the etching mask 42 shown in FIG. The etching mask 42, the gate electrode material 43, and the insulating film 45 that are present are removed to remove the silicon substrate 41.
The surface of is exposed as shown in FIG. 5 (f) (step 22). After that, photolithography is performed, and wet etching with an aqueous solution of hydrofluoric acid or ammonium fluoride or reactive ion etching with tetrafluoromethane is performed to form through holes 46 in the insulating film 45 as shown in FIG. To form. Next, a pyramidal recess 47 as shown in FIG. 5H is formed in the exposed silicon portion as in Example 1 (23rd step). At this time, in order to avoid etching of the back surface of the silicon substrate 41, the substrate 41
It is desirable to cover the back surface of the with a mask material.

Next, a field emission cathode material 48 is formed on the surface of the silicon substrate 41 by a sputtering method or a vacuum deposition method, and the conical recess 47 on the surface of the substrate 41 or the through hole 46 in the insulating film 45. Also, it is filled as shown in FIG. 5 (i) (24th step). After that, the field emission cathode material 4
The surface of 8 is photoengraved. At this time, photolithography is performed with a pattern 50 that allows the field emission cathode material on the through hole 46 provided in the insulating film to be removed. At this time, for example, in the case of a flat panel display using a field emission cathode, patterning is performed in a direction perpendicular to the gate electrode pattern 44 shown in FIG. -Get the Y matrix.

Next, the field emission cathode material 48 is etched by ion beam etching to expose the surface of the insulating film 45 and the surface of the through hole 49 in the insulating film 45 filled with the field emission cathode material 48, as shown in FIG. And exposed as shown in (25th step). After that, the substrate 41 is removed by wet etching using potassium hydroxide or reactive ion etching using tetrafluoromethane, and the field emission cathode 51 as an emitter cone is formed as shown in FIG.
It is exposed as shown in (h) (step 26). By the above method, the patterned gate electrode, the insulating layer,
A patterned field emission cathode can be formed. In this case, it is desirable to bond a support substrate supporting the field emission cathode 51 to the surface of the silicon substrate 41 before removing the silicon substrate 41.

Further, in this embodiment, not only the field emission cathode material 48 but also the gate electrode can be exposed on the back surface of the formed field emission cathode 51 by the electrode material with which the through hole 46 is filled. Therefore, it is not necessary to take a connecting electrode from the side surface of the silicon substrate 41, and when the silicon substrates 41 are tiled, the gap between the silicon substrate 41 and the bonding portion can be narrowed.

[0050]

As described above, according to the first aspect of the present invention, a photoresist is applied on the etching mask formed on the silicon substrate, and then photolithography is performed to form a part of the silicon substrate. Then, the other part is covered with a resist, and then the etching mask in the above part is dissolved and removed, and then pyramidal depressions are formed on the silicon substrate surface by anisotropic etching with an aqueous solution of potassium hydroxide. A field emission cathode material is formed on the surface of the silicon substrate from which the photoresist and the etching mask have been removed so that the recesses are filled, and finally, the silicon substrate is removed by etching to form the field emission cathode. Since the pyramid-shaped field emission cathode is exposed on the material, the metal field emission cathode material is formed on the upper surface of the silicon substrate including the depressions to etch the substrate. By removing the field-emission cathode material with a conical shape, it is possible to form a cone-shaped field-emission cathode having a high current density on the field-emission cathode material without scratching, and it is possible to easily control the shape of the field-emission cathode. ..

According to the second aspect of the present invention, after the photoresist is applied on the etching mask formed on the silicon substrate, photoengraving is performed, and some etching masks are left and the others are etched. Further, anisotropic dry etching of a certain depth is performed on the silicon substrate by reactive dry etching, and a gate electrode material and an insulating film are formed to have a predetermined thickness on the silicon substrate. The gate electrode material and the insulating film are removed to expose the surface of the silicon substrate, and a cone-shaped recess is formed in this exposed portion by anisotropic etching with an aqueous solution of potassium hydroxide, so that the recess is also filled. In addition, since the field emission cathode material is formed on the surfaces of the silicon substrate and the insulating film, and finally the silicon substrate is removed by etching, In the process of forming a field emission cathode, the gate electrode can be patterned on the silicon substrate to be removed in the final step, and therefore, it is possible to prevent damage after the formation of the field emission cathode. It is effective.

Further, according to the invention of claim 3, through holes are formed in the insulating film by etching, and conical recesses are formed in the exposed portion of the silicon substrate by anisotropic etching using an aqueous solution of potassium hydroxide. , Forming a field emission cathode material on the silicon substrate and the insulating film so that the recess and the through hole are also filled,
Patterning was performed so that the field emission cathode material on the through hole was removed, and finally, the silicon substrate was removed by etching, so that the field emission cathode material was filled and the gate electrode was taken out from the back surface. What makes it possible to form a terminal that makes it possible, and has a small joint gap when tiling is obtained at low cost.

Further, according to the invention of claim 4, after applying the photoresist on the etching mask formed on the silicon substrate, photolithography is carried out, and a part of the etching mask is left and the others are etched. Then, the silicon substrate is anisotropically etched to a certain depth by reactive dry etching, and a gate electrode material and an insulating film are formed on the silicon substrate to a predetermined thickness. , After forming the gate electrode material to a predetermined thickness, an arbitrary pattern is formed on a part of the surface of the gate electrode material by photolithography, and then the etching mask is removed to expose the surface of the gate electrode material. After that, an insulating film having a predetermined thickness is formed thereon, and the etching mask, the gate electrode material and the insulating film in the above part are removed, The surface of the substrate is exposed, through holes are formed in the insulating film other than the above part by etching, and conical recesses are formed in the exposed part of the silicon substrate by anisotropic etching with an aqueous potassium hydroxide solution. Then, a field emission cathode material is formed on the silicon substrate and the insulating film so that the recess, the through hole, and the pattern are filled, and the field emission cathode material on the through hole is removed. Since the silicon substrate is removed by etching at the end, it is possible to pattern the upper and lower gate electrodes as an XY matrix in the process of forming the field emission cathode, which can be easily flattened. There is an effect that a panel CRT that can be easily and inexpensively applied can be obtained.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram showing a method for manufacturing a field emission cathode according to an embodiment of the invention of claim 1;

FIG. 2 is an explanatory view showing the directions of crystal planes that appear by alkaline wet etching in FIG.

FIG. 3 is a manufacturing process diagram showing a method of manufacturing a field emission cathode according to an embodiment of the invention of claim 2;

FIG. 4 is a manufacturing process diagram showing a method for manufacturing a field emission cathode according to an embodiment of the invention of claim 3;

FIG. 5 is a manufacturing process diagram showing a method of manufacturing a field emission cathode according to an embodiment of the invention of claim 4;

FIG. 6 is a cross-sectional view showing a conventional field emission cathode.

FIG. 7 is a manufacturing process diagram showing a method of manufacturing a conventional vapor deposition type field emission cathode.

FIG. 8 is a manufacturing process diagram showing a method of manufacturing a conventional etching type field emission cathode.

[Explanation of symbols]

 11, 21, 31, 41 Silicon substrate 12, 22, 32, 42 Etching mask 13 Photoresist 14, 25, 36, 47 Recess 16, 26, 37, 48 Field emission cathode material 17, 27, 40, 51 Field emission Cathode 23, 33, 43 Gate electrode material 24, 34, 45 Insulating film 35, 38, 46 Through hole 39, 44, 45A, 50 pattern

Claims (4)

[Claims] 1. A photoresist is applied on an etching mask formed on a silicon substrate, and photoengraving is then performed.
The first step of leaving a part of the silicon substrate and the other part covered with the photoresist, and then, after the etching mask in the part is dissolved and removed, it is formed into a pyramid shape by anisotropic etching with an aqueous solution of potassium hydroxide. Second step of forming the depressions on the surface of the silicon substrate, and forming a field emission cathode material on the surface of the silicon substrate from which the photoresist and the etching mask have been removed so that the depressions are also filled. A method for producing a field emission cathode, which comprises performing a third step and finally, a fourth step of removing the silicon substrate by etching to expose the pyramidal field emission cathode on the field emission cathode material. 2. After applying a photoresist on an etching mask formed on a silicon substrate, photoengraving is performed,
A fifth step of etching the other while leaving a part of the etching mask, a sixth step of performing anisotropic dry etching of a certain depth on the silicon substrate by reactive dry etching, and a gate electrode on the sixth step. After forming the material and the insulating film to a predetermined thickness, the seventh step of exposing the surface of the silicon substrate by removing the etching mask, the gate electrode material and the insulating film in the above part, and water in the exposed part. Eighth step of forming a conical depression by anisotropic etching with an aqueous solution of potassium oxide, and ninth step of forming a field emission cathode material on the surfaces of the silicon substrate and the insulating film so as to fill the depression as well. A field emission method, which comprises a step and, finally, a tenth step of removing the silicon substrate by etching to expose a pyramidal field emission cathode on the field emission cathode material. A method for manufacturing a pole. 3. A photoresist is applied on an etching mask formed on a silicon substrate, and then photolithography is performed,
Eleventh step of etching the others while leaving a part of the etching mask, and further anisotropically etching the silicon substrate to a certain depth by reactive dry etching, and then forming a gate electrode material and an insulating film thereon. A twelfth step of forming a predetermined thickness, a thirteenth step of removing the etching mask, the gate electrode material and the insulating film in the part to expose the surface of the silicon substrate, and further etching the insulating film. 14th step of forming a conical recess in the exposed portion of the silicon substrate by anisotropic etching with an aqueous solution of potassium hydroxide, so that the recess and the through hole are also filled. Fifteenth step of forming a field emission cathode material on the silicon substrate and the insulating film, and the field emission cathode on the through hole A 16th step of patterning so that the material is removed, and finally, a 17th step of removing the silicon substrate by etching to expose the conical field emission cathode on the field emission cathode material. Method for manufacturing field emission cathode. 4. A photoresist is applied on an etching mask formed on a silicon substrate, and photoengraving is then performed.
An eighteenth step of etching the other part while leaving a part of the etching mask, and further anisotropically etching the silicon substrate to a certain depth by reactive dry etching, and applying a gate electrode material to a predetermined thickness on the anisotropic etching. 19th step of forming the gate electrode material, and 20th step of forming an arbitrary pattern on the surface of the gate electrode material by photolithography, and then removing the etching mask to expose the surface of the gate electrode material. After that, a twenty-first step of forming an insulating film with a predetermined thickness thereon, and a step of further removing the etching mask, the gate electrode material and the insulating film in the above part to expose the surface of the silicon substrate 22 step, through holes are formed in the insulating film other than the above part by etching, and the exposed portion of the silicon substrate is exposed to an aqueous solution of potassium hydroxide. Twenty-third step of forming a conical recess by a resistive etching, and twenty-fourth step of forming a field emission cathode material on the silicon substrate and the insulating film so that the recess and the through hole are also filled, Twenty-fifth step of patterning such that the field emission cathode material on the through hole is removed, and finally, the silicon substrate is removed by etching to form a cone-shaped field emission cathode on the field emission cathode material. And a twenty-sixth step of exposing.