JP3471327B2 - Manufacturing method of micro emitter array - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a micro-emitter (field emission device) which is a kind of vacuum device and a flat display device using the same.

[0002]

2. Description of the Related Art Conventionally, a vacuum device using vacuum as a charge transport medium has been studied, and a micro emitter (field emission device) is one of the vacuum devices. As a method of manufacturing the micro-emitter, there are known a method of performing fine processing using an etching process and a method of performing oblique incidence deposition by sputtering a film forming material.

There are Spindt type and wedge type as typical micro-emitters. In the case of the Spindt type, the emitter electrode has a shape of a quadrangular pyramid or a cone. A square or circular resist mask is used to fabricate the Spindt-type micro-emitter, and the Si substrate is anisotropically or isotropically etched. And this manufacturing technique is shown by the following reference documents 1, for example.

Reference 1: Electron Magazine, Vol. 112, No. 4, 1992, pp257-262 Further, in the case of a wedge type, an in-plane has a triangular plunge plate shape, and an etching process is used for manufacturing. To be executed. The technique for manufacturing the wedge-shaped micro-emitter is described in, for example, Reference Document 2 below. Reference 2: OPTRONICS, 1991, N
o. 1, pp193-198

[0005]

In the Spindt-type micro-emitter, the tip of each emitter electrode is sharper than that of the wedge-type, but it is easy to sharpen a plurality of emitter electrodes without variation. is not. Also, the emission current can be emitted more efficiently as the apex angle of the emitter electrode is smaller, but in the case of fabrication by anisotropic etching, the apex angle is determined by the plane orientation, so the emitter electrode can be sharpened freely. You cannot do it. Furthermore, when it is produced by isotropic etching, it is more difficult to control the apex angle.

On the other hand, in the wedge type micro-emitter, the sharpening of the apex angle depends on the patterning accuracy of the etching mask (resist mask or the like), and is therefore limited by the resolution of the patterning device.

Each invention has been made to solve the above problems.

It is an object of the present invention to provide a field emission device having a high emission current emission efficiency.

According to a first aspect of the present invention, a micro-emitter array including a substrate, an insulating film and a conductive film that are sequentially stacked on the substrate, and a plurality of recesses that are opened on the surface of the conductive film are manufactured. In the method, a molecule of conductive material is included.
Simultaneously irradiating each of the recesses with a light beam in a gas atmosphere, the conductive material is removed from the substrate forming the bottom surface of the recesses.
And a step of causing the tip of the emitter electrode to protrude from the conductive film.

Further , instead of the light beam, an ion beam or
An electron beam may be used.

According to the present invention, the emission of the emission current is
The output efficiency is high and the emitters can be brought close together.
Therefore, it is easy to obtain a high value of emission current.
You can

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 8 show an embodiment of the present invention.
Further, reference numeral 1 in FIG. 1 is an apparatus for producing an emitter electrode (needle-shaped substance) of a microemitter. The emitter electrode manufacturing apparatus 1 includes a light source 2, a first optical system 3, a mask substrate 4, a second optical system 5, and a chamber 6.
Is provided.

Of these, the light source 2 outputs an optical beam 7 as an excitation beam. The optical beam 7 is a circular beam having a sufficiently large diameter and has a sufficiently high energy. Further, the energy distribution (light intensity distribution) shape of the light beam 7 has a Gaussian distribution shape as shown in the graph 8 on the right side of the drawing. Further, the first optical system 3 makes the energy distribution of the light beam 7 uniform as shown in the lower graph 9. As the first optical system, it is possible to use, for example, a general Gaussian compensator or a kaleidoscope.

In the mask substrate 4, as shown in part in FIG. 2, a light shielding film 12 is patterned on a glass plate 10 leaving a plurality of round holes 11. The glass plate 10 has a light-transmitting property, and the round holes 11 ... Are regularly arranged in accordance with the arrangement of the emitter electrodes to be manufactured. A part of the light beam 7 which has passed through the first optical system 3 and reached the mask substrate 4 is blocked by the light shielding film 12.
The optical beam reaching the glass plate 10 through the round holes 11 ...
Subdivided into a plurality of optical beams (multi-beams) 7b ...
It is incident on the second optical system 5 in parallel. At this time, each light beam 7b has a Gaussian intensity distribution due to the action of the edges of the round holes 11.

The second optical system 5 is composed of a combination of lenses and the like, and reduces the beam diameter and spacing of the optical beams 7b ... At a predetermined ratio. Then, the reduced light beams 7c ... Are guided to the chamber 6 and irradiated on the substrate 13 (described later) for the micro-emitter array housed in the chamber 6.
A gas (for example, WF6) containing molecules of a predetermined conductive substance is introduced into the chamber 6, and as shown in FIG. 3, the molecules 14 containing the conductive substance in the atmosphere are light beams. It is excited and decomposed by 7c.

As shown in FIGS. 5A and 5B, the substrate for the micro-emitter array (hereinafter referred to as an array substrate) 13 has an insulating film 16 and a conductive film 17 laminated on a Si substrate 15. It will be done. In this embodiment,
SiO 2 is used as the material of the insulating film 16, and WSi is used as the material of the conductive film 17.

The Si substrate 15 has a perfect circular shape.
The plate surface of the substrate 15 is processed into a highly accurate flat surface. A plurality of recesses 18 for forming an emitter electrode are formed on the array substrate 13, and these recesses 18 are regularly arranged. The recesses 18 open in the conductive film 17 in a perfect circle shape. Further, the recesses 18 penetrate the conductive film 17 and the insulating film 16, and the Si substrate 1 is provided at the bottom of the recesses 18 ...
The plate surface of No. 5 is exposed.

The array substrate 13 is manufactured as follows. First, in order to manufacture the array substrate 13,
A mask having a substantially circular resist pattern is used. A large number of resist patterns are formed in accordance with the number of emitter electrodes to be manufactured, and are arranged at intervals corresponding to the arrangement of the recesses 18 ... As shown in FIG. 6 (a),
First, anisotropic etching (RI
Then, the insulating film 16 is processed as shown in FIG.

Further, as shown in (c), the conductive film 17
Is deposited (sputtering, CVD, etc.), and the resist 20 is patterned (superposed) as shown in FIG. Then, anisotropic etching and isotropic etching (CDE or the like) are performed, and the insulating film 16 and the conductive film 17 are processed as shown in (e).

Next, a method of manufacturing an emitter electrode using the above-described emitter electrode manufacturing apparatus 1 and array substrate 13 will be described. First, the light beam 7 output from the light source 2 passes through the first optical system 3, and the energy distribution shape of the light beam 7 changes from a Gaussian distribution shape (upper graph 8) to a uniform distribution shape (lower graph). Is converted into graph 9). This conversion is performed so that each of the light beams 7b ... Has a substantially uniform Gaussian distribution shape when the light beam 7a is subdivided next. Next, the optical beam 7a emitted from the first optical system 3
Are subdivided by the mask substrate 4 to have a Gaussian intensity distribution, and the second optical system 5 reduces the subdivided optical beams 7b ... With the same intensity distribution. Then, the reduced light beams 7c ... Are guided into the chamber 6 and reach the array substrate 13. The optical beams 7c enter the center of the recesses 18 of the array substrate 13 and the Si substrate 15
It is irradiated vertically to.

The arrangement of the optical beams 7c is the same as the arrangement of the concave portions 18 of the array substrate 13, and the beam diameter D1 of each optical beam 7c is set smaller than the diameter of each concave portion 18. Has been done.

Since the gas containing the molecules of the conductive substance is introduced into the chamber 6, as shown in FIG. 3, the molecules 14 containing the conductive substance (W in this case) in the atmosphere are exposed to light. Excited and decomposed by the beam 7c. The decomposed conductive molecules 14 are deposited on the Si substrate 14 along the optical beam 7c. By continuously irradiating the Si substrate 15 with the light beam 7b, the deposit gradually grows. further,
The range in which the gas molecules 14 are deposited substantially coincides with the irradiation range of the light beam 7b. As a result, the needle-shaped substance made of a conductive material and the emitter electrode 21 as the needle-shaped electrode are formed on the Si substrate 15. Since a large number of optical beams 7c ... Converge in each of the recesses 17 ..., a large number of emitter electrodes 2 are simultaneously formed.
1 ... is produced. At this time, when the Gaussian intensity distributions of the light beam 7c have the same integral value, the sharper the emitter electrode 2 is, the smaller the half width is.
1 will be formed.

The cross-sectional shape of each emitter electrode 21 is a light beam.
The shape is a perfect circle, which is the same as the spot shape of the frame 7c. The diameter D2 of the emitter electrode 21 is substantially equal to the beam diameter D1 of the optical beam 7c. The length of each emitter electrode 21 (the amount of protrusion from the Si substrate 15) increases in proportion to the irradiation time of the light beam 7c.

Further, the shape of the tip 22 of each emitter electrode 21 has a correlation with the shape of the energy density distribution of the optical beam 7b, and as shown in FIGS. 4 (a) and 4 (b), the tip 22 is formed. The radius of curvature of is substantially similar to the curvature of the energy density distribution curve 23. The radius of curvature of the tip 22 is 1/10 of the beam diameter D1 of the optical beam 7b. In this embodiment, the radius of curvature of the tip 22 is, for example, 1000
It can be set smaller than the angstrom.

Thus, one emitter electrode 21 is formed in each recess 18 of the array substrate 13. As shown in FIG. 7, each emitter electrode 21 constitutes a micro-emitter 24, and as shown in FIG. 8, a plurality of micro-emitters 24 ... Constitute a micro-emitter array 25. The number of micro-emitters 24 ... Formed in one micro-emitter array 25 is determined by the number of round holes 11 ... In the mask substrate 4 and the diameter of the optical beam 7.

Further, in order to increase the density of the formation intervals of the micro-emitters 24 ..., The density of the formation intervals of the round holes 11 is increased, or the aperture angle of the second optical system 5 is increased to make the light beam 7C. It is achieved by increasing the existing density of. Further, instead of the mask substrate 4, an optical fiber or a lens is used, where the light beam 7b has a multi-mode intensity distribution, or the second beam.
This can also be achieved by making the optical beam 7c have a multi-mode intensity distribution in the optical system 7. At that time, each emitter electrode 21
It can be prevented by increasing the output of the light source.

According to the method for producing an emitter electrode as described above, compared to the conventional method for producing an emitter electrode,
There are advantages such as (1) to (4). (1) Similarity of tip shapes of a large number of emitter electrodes In the conventional method of manufacturing an emitter electrode, the shape accuracy of the emitter electrode depends on the accuracy of mask patterning. Therefore, it is difficult to manufacture an emitter electrode having a uniform shape. And when the shape of each emitter electrode is non-uniform, even if the same electric field is applied to many emitter electrodes,
The value of each emission current is different.

On the other hand, according to the method of manufacturing the emitter electrode of the present embodiment, the shape of the tip 22 of the emitter electrode 21 depends on the energy density distribution of the light beams 7c, so that the patterning of the mask substrate 4 is performed. Several other emitter electrodes 21 having sharp tips 22 are manufactured at the same time without being affected by accuracy. Further, the optical beam 7 is evenly subdivided by the first optical system 3 and the mask substrate 4, and the array substrate 13
Is irradiated. Therefore, it is possible to obtain the emitter electrodes 21 ... Having a uniform shape with little variation in shape accuracy. The tip shapes of many emitter electrodes are highly similar. (2) Field emission characteristics In general, the factors necessary to increase the emission current are
The apex angle of the emitter electrode is small, the tip of the emitter electrode is appropriately protruded from the extraction electrode (gate electrode = second conductive film 17 in this embodiment), and the radius of curvature of the tip. Is small. In the conventional Spindt-type micro-emitter, the apex angle of the emitter electrode is large, and the tip of the emitter electrode cannot protrude beyond the extraction electrode. Further, in the conventional wedge-shaped micro-emitter, it is difficult to emit electrons right above.

On the other hand, according to the method of manufacturing the emitter electrode of the present embodiment, the curvature of the tip 22 of the emitter electrode 21 can be adjusted by the energy density distribution of the light beams 7c ... It is easy to do. Further, since the length of the emitter electrode 21 is determined by the irradiation time of the light beam 7c, the emitter electrode 21 can be easily projected beyond the conductive film 17. Therefore,
The emission efficiency of emission current is high, and a high value of emission current can be easily obtained. (3) Emission current density In general, the emission current density is higher as the number of emitter electrodes is larger within a predetermined range. In the conventional micro-emitter, since there is a limit to miniaturization of the apex angle of the emitter electrodes, it is difficult to bring the emitter electrodes close to each other, and the emission current is restricted by the distance between the adjacent emitter electrodes. In particular, in the case of a Spindt-type micro-emitter, the emission current increases as the distance between the substrate and the extraction electrode increases, so the base of the emitter is also set large. As a result,
The distance of the tip of the emitter electrode increases.

On the other hand, according to the method for manufacturing the emitter electrode of the present embodiment, the emitter electrode 21 is needle-shaped and the tip 22 has a radius of curvature of 1000 angstroms.
It can be set smaller than the frame. Therefore, the emitter electrode 2
1 can be brought closer to each other (up to the patterning limit of the conductive film 17) than before, and a high emission current can be obtained. (4) Ease of Process According to the method of manufacturing the emitter electrode of the present embodiment, the number of steps in the manufacturing process is small because etching back is not required after manufacturing the emitter electrode. Further, since the light beams 7c ... Are guided to the recesses 18 of the array substrate 13, the emitter electrode 21 can be manufactured regardless of the depth of the recesses 18. Therefore,
The emitter electrode 21 can be formed in a portion having a high aspect ratio.

The present invention can be variously modified without departing from the scope of the invention. In the above embodiment, the mask substrate 4 is used to replace the light beam 7a with the light beam 7a.
Although subdivided into b, instead of the mask substrate 4, a round hole 1
Even if the number of lenses or optical fibers corresponding to 1 is used, the effect is the same. At this time, the light beam 7b also has a Gaussian intensity distribution.

In this embodiment, W is used as the conductive molecule, but any molecule containing various conductive substances can be applied as long as it can be excited and decomposed by the excitation beam. For example, if an oxide of Re is adopted, the adhesion to the chamber 6 can be prevented.

Further, although the optical beam 7 is used as the excitation beam in this embodiment, for example, the manufacturing apparatus 31 shown in FIG.
As described above, the ion beam 32 may be used. That is, the manufacturing apparatus 31 is provided with the ion beam source 33 and the conductive substrate 34. The diameter of the ion beam 32 is set to be sufficiently large and the energy thereof is also set to be sufficiently high. Further, as shown in the graph 35 on the right side of the drawing, the energy distribution (ion energy distribution) of the ion beam 32 is substantially uniform. Conductive substrate 3
4, a plurality of round holes 36 ... Are formed, a part of which is shown in FIG. 10. These round holes 36 ... Are regularly arranged in accordance with the arrangement of the emitter electrodes to be manufactured. ing.

The ion beam 32 is passed through the conductive substrate 34 and subdivided into a plurality of pieces. The subdivided ion beam 32 has a Gaussian intensity distribution. A power source 37 is connected to the conductive substrate 34, and the ion beam 32 is accelerated / decelerated according to the value of the applied voltage. The subdivided ion beams 32a ... Are guided to the chamber 6 and the array substrate 13
Reach The ion beam 32a ... is the Si substrate 1
4 is irradiated onto the Si substrate 14 and a large number of emitter electrodes 2
1 ... are simultaneously produced.

As the ion beam source 33, for example, a Kauffman type ion source can be used.
Alternatively, a plurality of conductive substrates 34 may be used and may be arranged between the ion beam source 33 and the chamber 6 with an appropriate interval. By using a plurality of conductive substrates 34, the ion beams 32a ... Can be converged and polarized.

Further, as in the manufacturing apparatus 41 of FIG. 11, electron beams 42 ... Can be used as the excitation beam. That is, the manufacturing apparatus 41 is provided with an electron beam source 43 which emits a plurality of electron beams 42 and a conductive substrate 34, and the electron beam output from the electron beam source 43. Four
2 ... are subdivided by the conductive substrate 34. Electronic bee
As the source 43, for example, the Spindt-type ultrafine bipolar vacuum tube (reference 1) described in the section of the related art can be used. Also, electron beam sources that emit one electron beam may be collected and used as the electron beam source 43.

The energy distribution (current density distribution) shape of each electron beam 42 ... Is a Gaussian distribution shape as shown in the graph 44 on the right side of the figure, and the electron beam 42 ...
By passing 4, the energy distribution has a plurality of uniform Gaussian distributions as shown in the lower graph 45.

The subdivided electronic beam 42a ...
Are guided to the chamber 6 and a large number of emitter electrodes 21 ... Are simultaneously formed on the Si substrate 15. Note that a plurality of conductive substrates 34 may be used to converge and polarize the electron beams 42a. Further, if the distance between the electron beam source 43 and the conductive substrate 34 is set so as to obtain an energy distribution that narrows the distance between the Gaussian intensity distributions as shown in the lower graph 45, the electron beam source The emitter electrode can be formed more densely than the cathode group.

Even if an electron beam source that emits only one electron beam is used, the electron beam is made to have a uniform energy distribution by an electrostatic lens (not shown), and then the conductive substrate is used. 34
The same effect can be obtained by passing through.

Further, the electron beams 42 ... Are connected to the conductive substrate 3.
By decelerating at 4, it is possible to prevent adverse effects caused by the high-energy electron beam (for example, rebounding of the electron beam). Also,
12A to 12D show a modification of the method for manufacturing the array substrate 13. In this method, first,
As shown in (a), the insulating film 16 and the conductive film 1 are formed on the Si substrate 15.
After 7 and 7 are stacked, the resist pattern 51 is overlapped as shown in (b), and anisotropic etching (c) and isotropic etching (d) are performed.

During anisotropic etching, the resist pattern is used.
It is conceivable that the conductive film 17 will be erased during the etching, but if the conductive film 17 is formed thick in advance, the conductive film 17 can be used as a mask.

In both cases of FIG. 9 and FIG. 11, if a voltage is applied to the conductive film 17 as shown in FIG. 13, the array substrate 13 can be used without using the conductive substrate 34.
The excitation beam can be converged in the recess 18 of the. In this case, the alignment of the array substrate 13 becomes easy, and the process becomes easier.

Further, as shown in FIG. 14, if a plurality of insulating films 16 and a plurality of conductive films 17 are alternately laminated to form a needle-shaped emitter electrode, a multi-electrode vacuum tube 61 is formed.
And a multi-electrode vacuum tube array 62 can be obtained.

Further, the micro-emitter array 25 shown in FIG.
Can be used as an electron source of a flat panel display device by combining a large number as a bipolar tube array. Then, in this case, it is conceivable that a bipolar vacuum tube array is made to correspond to each small region of the flat display, and an electron beam is scanned for each small region to cause the fluorescent screen to emit light.

The multi-electrode vacuum tube 61 shown in FIG. 14 can be used as an electron source of an electron beam direct writing apparatus (patterning apparatus). Furthermore, the multi-electrode vacuum tube 61 of FIG.
Can also be used as an electron source of a scanning electron microscope.

According to the present invention, the emission current is released.
The output efficiency is high and the emitters can be brought close together.
Therefore, it is easy to obtain a high value of emission current.
You can

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an emitter electrode manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing the action of a mask substrate.

FIG. 3 is an explanatory diagram showing a principle of manufacturing an emitter electrode.

FIG. 4 is an explanatory diagram showing the relationship between the shape of the tip of an emitter electrode and the energy density distribution of an optical beam.

5A is a perspective view showing a substrate for a microemitter array, and FIG. 5B is a sectional view taken along line IV-IV in FIG. 5A.

FIG. 6 is an explanatory diagram showing a method for manufacturing a substrate for a micro-emitter array.

FIG. 7 is an explanatory diagram showing a state in which an emitter electrode is formed on a substrate for a microemitter array.

FIG. 8 is a perspective view showing a micro-emitter array.

FIG. 9 is a configuration diagram showing a modified example of a method for manufacturing an emitter electrode.

FIG. 10 is an explanatory view showing the action of the conductive substrate.

FIG. 11 is a configuration diagram showing another modification of the method for manufacturing an emitter electrode.

FIG. 12 is an explanatory diagram showing a modified example of the method for manufacturing the substrate for the micro-emitter array.

FIG. 13 is an explanatory diagram showing a modified example of the method for manufacturing an emitter electrode.

FIG. 14 is an explanatory diagram showing a method for manufacturing a multi-electrode vacuum tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Emitter electrode manufacturing apparatus, 4 ... Mask substrate, 6 ... Chamber, 7, 7a to 7c ... Optical beam (excitation beam), 13
... Substrate for microemitter array, 14 ... Conductive molecule, 15 ... Si substrate (substrate), 21 ... Emitter electrode (needle-like substance), 24 ... Microemitter (field emission device),
25 ... Micro-emitter array, 32, 32a ... Ion beam (excitation beam), 42, 42a ... Electron beam (excitation beam).

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Claims (3)

(57) [Claims] 1. A method for manufacturing a micro-emitter array, comprising: a substrate; an insulating film and a conductive film that are sequentially stacked on the substrate; and a plurality of recesses that are opened on the surface of the conductive film . Simultaneously irradiating each of the recesses with a light beam in a gas atmosphere containing molecules of a substance, the emitter electrodes containing the conductive substance are grown from the substrate forming the bottom surface of the recess, and the tip of the emitter electrode is A method of manufacturing a micro-emitter array, comprising the step of projecting the conductive film from a conductive film. 2. A method for manufacturing a micro-emitter array, comprising: a substrate; an insulating film and a conductive film that are sequentially stacked on the substrate; and a plurality of recesses that are open on the surface of the conductive film . Simultaneously irradiating each of the recesses with an ion beam in a gas atmosphere containing a molecule of a substance to grow emitter electrodes containing the conductive substance from the substrate forming the bottom surface of the recesses. A method of manufacturing a micro-emitter array, comprising the step of projecting the conductive film from a conductive film. 3. A method for manufacturing a micro-emitter array, comprising: a substrate; an insulating film and a conductive film that are sequentially stacked on the substrate; and a plurality of recesses that are open on the surface of the conductive film . The recesses are simultaneously irradiated with an electron beam in a gas atmosphere containing molecules of a substance to grow emitter electrodes containing the conductive substance from the substrate forming the bottom surface of the recesses. A method of manufacturing a micro-emitter array, comprising the step of projecting the conductive film from a conductive film.