JP3171423B2 - Method for forming microstructure and method for manufacturing field emission electron source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantum effect device which applies a quantum effect generated in a microstructure of a semiconductor or the like, and an electron beam excitation using a vacuum electron radiated from a steep tip of a cathode by an electric field effect. The present invention relates to a method for forming a microstructure of a cold cathode electron source applicable to a laser, a flat solid-state display device, an ultra-high speed micro vacuum device, and the like, and a method for manufacturing a field emission electron source.

[0002]

2. Description of the Related Art With the development of semiconductor microfabrication technology, it is becoming possible to form quantum effect devices and field emission type cathodes.

For example, after forming a fine line-shaped etching mask on the (100) plane of a silicon substrate by a fine processing technique, dry etching and anisotropic wet etching are performed on the silicon substrate using the etching mask.
After that, by subjecting the silicon substrate to thermal oxidation,
2. Description of the Related Art A technique for forming a quantum wire below an etching mask on a silicon substrate is known. JP-A-4-6285
The method of producing a quantum wire reported by Hirai et al. In Japanese Patent Publication No. 4 will be described with reference to FIGS.

First, as shown in FIG. 8A, an insulating film 102 is formed on a (100) plane of a silicon substrate 101, and then, as shown in FIG. A thin linear mask 103 having a width of about 1 μm is formed in the <100> direction of the substrate 101 by ordinary photolithography. Thereafter, as shown in FIG. 8C, the silicon substrate 101 is dry-etched using a fine line-shaped etching mask 103, thereby forming a convex portion 104 protruding from the surface of the silicon substrate 101.

[0005] Next, as shown in FIG.
By performing anisotropic wet etching on the side surface of the lower surface 04, the surface becomes a (111) surface and the lower portion 1 having a truncated pyramid shape is formed.
A three-dimensional structure 105 composed of the upper portion 105a and an inverted truncated pyramid-shaped upper portion 105b is formed. Thereafter, as shown in FIG. 9B, the side surface portion of the three-dimensional structure 105 is subjected to a thermal oxidation treatment, thereby changing the side surface portion of the three-dimensional structure 105 to an insulating silicon oxide film 107. Top 1 of 105
A quantum wire 108 made of silicon is formed inside 05b.

On the other hand, there has been proposed a method of manufacturing a field emission type electron source made of silicon by applying a fine processing technique to a silicon substrate in the same manner as described above. For example, Gray et al. Have proposed a cone-type field emission cathode in which the shape of an emitter can be relatively easily controlled by using a silicon substrate and performing anisotropic etching on the silicon substrate. 2: HFGray., Proc.29th Int
ern. Field EmissionSymp. p.111 (1982).

A field emission type cathode proposed by Gray et al. And a method for producing the same will be described with reference to FIGS. 10 and 11. FIG.

First, as shown in FIG. 10A, a silicon oxide film 112 is formed on a (100) plane of a conductive substrate 111 made of silicon, and then, as shown in FIG. A circular etching mask 113 is formed on the film 112 by ordinary photolithography. Thereafter, the conductive substrate 111 is anisotropically etched using the etching mask 113 to form a conical body 114 made of silicon crystal below the etching mask 113.

Next, as shown in FIG. 11A, an insulating film 115 and a metal film 116A are sequentially deposited, and a gate electrode 11 is formed around the conical body 114 via the insulating film 115.
6B is formed. At this time, since the etching mask 113 serves as a mask for preventing deposition, the insulating film 115 and the metal film 116A are not deposited on the side surfaces of the conical body 114.
After that, the etching mask 113 is removed to form a field emission type cathode 117.

The tip of the cathode 117 includes a (111) plane which is a crystal plane having a low etching rate, and the inclination angle is determined by the intersection angle of the crystal plane inclined with respect to the (100) plane of the silicon substrate 111. Has been proposed to form a silicon oxide film on the side surface of the cathode 117 by thermal oxidation in order to further increase the sharpness.

As another method for producing a field emission type cathode using a silicon substrate, Beshii proposed dry etching of a silicon substrate under conditions where side etching occurs in order to realize a steeper cathode tip. A method combining thermal oxidation treatment with a silicon substrate has been proposed (Ref. 3: Besui, 1990-2007 IEEJ General Papers 5, SC-8-2 (1990)).

A field emission type cathode proposed by Besui and a method of manufacturing the same will be described with reference to FIGS.

First, as shown in FIG. 12A, a silicon oxide film 132 is formed on the surface of a silicon substrate 131, and then, as shown in FIG.
Then, a circular etching mask 133 is formed by ordinary photolithography. Then, FIG.
As shown in (c), by performing dry etching on the silicon substrate 131 using the etching mask 133 under the condition that side etching occurs, a truncated conical body 134 having a surface 134a substantially perpendicular to the side is formed. Is formed, and the etching mask 133 is
The etching is completed in a state where the substrate is supported by the substrate 4. Thereafter, when a silicon oxide film 135 is formed on the side surface of the truncated cone 134 by thermal oxidation, a very sharp tip portion 134b made of silicon is formed inside the truncated cone 134.
Is formed.

Next, as shown in FIG. 13A, an insulating film 137 and a metal film 138A are deposited on the periphery of the truncated conical body 134 via an etching mask 133, and are deposited on the silicon substrate 131. A gate electrode 138 </ b> B is formed around the truncated conical body 134 via an insulating film 137. Thereafter, as shown in FIG. 13B, the etching mask 133 is removed, and a field emission type cathode 139 is manufactured.

[0015]

In the method of manufacturing a quantum wire proposed by Hirai, the three-dimensional structure 105 is determined by the width of the thin line-shaped etching mask 103, the depth of dry etching, the conditions of anisotropic etching, and the like. Of the quantum wires 10 formed by remaining in the three-dimensional structure 106 without being oxidized after the thermal oxidation treatment,
5 is difficult to control. For this reason, according to the conventional method of manufacturing a quantum wire, there is a problem that it is difficult to manufacture a quantum effect element with good reproducibility. Although it is possible to manufacture a quantum effect device with good reproducibility by using an electron beam exposure method or an X-ray exposure method, these methods have a problem that they are expensive.

In the method of manufacturing a field emission type electron source proposed by Gray and Bessai et al., The conical body 114 or the truncated conical body on the lower side of the circular etching masks 113 and 133 depends on the etching conditions. Since the size of the portion in contact with the etching masks 113 and 133 at the apex of 134 differs, in the case of over-etching, the tip of the cathode 139 formed after the etching masks 113 and 133 are detached or formed after thermal oxidation. While it is buried inside the electrode 138, in the case of under-etching, the cathodes 113 and 139 having steep tips cannot be formed. As described above, according to the conventional method of manufacturing a field emission type electron source, there is a problem that it is difficult to strictly control the dimension of a portion in contact with the etching mask at the apex of the conical or frustoconical body. there were.

According to the present invention, there is provided a method for forming a microstructure having a size in a submicron region smaller than a minimum exposure size by an inexpensive ultraviolet exposure method, and a cathode having a sharp tip shape. It is an object of the present invention to provide a method for manufacturing a field emission type electron source provided with high reproducibility.

[0018]

Means for Solving the Problems In order to achieve the above object, a solution taken by the invention of claim 1 is to provide a method for forming a microstructure by forming an object having a first diameter of a predetermined size on a substrate. A first step of forming an etched three-dimensional structure and a monitoring three-dimensional structure having a second diameter smaller than the first diameter by a predetermined dimension difference equal to or smaller than the minimum exposure dimension, and the three-dimensional structure to be etched; A second step of forming a fine three-dimensional structure having a diameter corresponding to the predetermined dimensional difference on the substrate by etching each side surface of the three-dimensional structure for monitoring until the three-dimensional structure for monitoring disappears; And the steps described above.

According to a second aspect of the present invention, in the configuration of the first aspect, the planar shape of the three-dimensional structure to be etched and the three-dimensional structure for monitoring are linear or dot-like, respectively, and the fine three-dimensional structure is linear. Alternatively, a configuration in which the mask is a dot-like etching mask is added.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the second step includes irradiating the monitor three-dimensional structure with light and the intensity of reflected light from the monitor three-dimensional structure. Is monitored, and the etching on the side surface of the three-dimensional structure to be etched is terminated when the intensity of the reflected light decreases.

According to a fourth aspect of the present invention, in the configuration of the first or second aspect, the first step is to form a plurality of monitor three-dimensional structure rows comprising the plurality of monitor three-dimensional structures on the substrate at predetermined intervals. The second step includes irradiating light to the three or more monitor three-dimensional structure rows and diffracting light from the three or more monitor three-dimensional structure rows. And monitoring the intensity of the diffracted light and terminating the etching on the side surface of the three-dimensional structure to be etched when the intensity of the diffracted light decreases.

In a fifth aspect of the present invention, a method for forming a microstructure includes the steps of: forming a first three-dimensional structure to be etched having a first diameter of a predetermined size on a substrate; A second etched three-dimensional structure having a second diameter larger by a first predetermined dimension difference and a third diameter smaller than the first diameter by a second predetermined dimension difference smaller than the minimum exposure dimension. A first step of forming a three-dimensional structure for monitoring; and a three-dimensional structure for monitoring with respect to each side of the first three-dimensional structure to be etched, the second three-dimensional structure to be etched, and the three-dimensional structure for monitoring. By performing etching until the body disappears, a first micro three-dimensional structure having a diameter corresponding to the second predetermined dimensional difference on the substrate, and the first micro three-dimensional structure having a diameter corresponding to the first micro three-dimensional structure, A second micro-stand having a diameter larger by a predetermined dimension difference It is an arrangement that includes a second step of forming a structure.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the planar shapes of the first etched three-dimensional structure, the second etched three-dimensional structure, and the monitoring three-dimensional structure are linear or dot-like, respectively. The first micro three-dimensional structure and the second micro three-dimensional structure are each added with a configuration in which each of them is a linear or dot-like etching mask.

According to a seventh aspect of the present invention, in the configuration of the fifth or sixth aspect, the second step includes irradiating the monitor three-dimensional structure with light, and the intensity of reflected light from the monitor three-dimensional structure. And a step of ending the etching on each side surface of the first etched three-dimensional structure and the second etched three-dimensional structure when the intensity of the reflected light decreases. is there.

According to an eighth aspect of the present invention, in the configuration of the fifth or sixth aspect, the first step is to form a plurality of monitor three-dimensional structure rows comprising the plurality of monitor three-dimensional structures on the substrate at predetermined intervals. The second step includes irradiating light to the three or more monitor three-dimensional structure rows and diffracting light from the three or more monitor three-dimensional structure rows. The intensity of the diffracted light is monitored, and when the intensity of the diffracted light decreases, the etching of each side surface of the first etched three-dimensional structure and the second etched three-dimensional structure is terminated. .

In a ninth aspect of the present invention, a method for forming a microstructure includes the steps of: providing an etching mask having a first diameter of a predetermined size on a substrate; and a minimum exposure dimension smaller than the first diameter. A first step of forming a monitor mask having a second diameter smaller by a predetermined dimension difference; and forming the monitor mask below the monitor mask using the etching mask and the monitor mask with respect to the substrate. A second step of forming a fine three-dimensional structure having a diameter corresponding to the predetermined dimensional difference by performing etching until the three-dimensional structure to be removed disappears or separates from the monitoring mask. Configuration.

According to a tenth aspect of the present invention, in the configuration of the ninth aspect,
The monitoring mask, the etching mask, and the fine three-dimensional structure are each added with a configuration in which the planar shape is linear or dot-shaped.

[0028] According to the eleventh aspect of the present invention, in the configuration of the ninth aspect,
The substrate is made of a material that forms a thin film having a composition different from the original composition on the surface of the substrate by a predetermined chemical reaction, and the side surface of the micro three-dimensional structure formed in the second step is provided with the predetermined chemical Causing a reaction to form a thin film having a composition different from the original composition on the side surface portion, and then removing the thin film to reduce the diameter of the fine three-dimensional structure to less than the predetermined dimensional difference. This is to add a configuration that further includes a process.

According to a twelfth aspect of the present invention, in the configuration of the ninth aspect,
The substrate is made of a material having a composition different from the original composition on its surface by a predetermined chemical reaction, and a thin film which is selectively etched by a specific solution is formed. The predetermined chemical reaction is caused on the side surface of the structure to form a thin film having a composition different from the original composition on the side surface, and then the thin film is removed by wet etching with the specific solution. A configuration is further added in which a third step of making the diameter of the fine three-dimensional structure smaller than the predetermined dimensional difference is further provided.

The invention of claim 13 is the invention of claim 11 or 12
To the above configuration, the composition of the substrate is silicon and the composition of the thin film is silicon oxide.

According to a fourteenth aspect of the present invention, the configuration of the ninth to thirteenth aspects further includes a configuration in which the etching in the second step is dry etching or wet etching accompanied by side etching.

According to a fifteenth aspect of the present invention, in the configuration of the ninth to thirteenth aspects, the second step includes performing dry etching on the substrate using the etching mask and the monitoring mask. After forming a three-dimensional structure consisting of convex parts protruding from the surface of the three-dimensional structure, wet etching is performed on the side surface of the three-dimensional structure until the three-dimensional structure no longer supports the monitoring mask, thereby reducing the predetermined dimensional difference. This is an additional step of forming a micro three-dimensional structure having a corresponding diameter.

According to a sixteenth aspect of the present invention, in the configuration of the ninth to fifteenth aspects, the second step includes irradiating the monitor mask with light and monitoring the intensity of light reflected from the monitor mask. An additional feature is that the method includes a step of terminating the etching of the substrate when the intensity of the reflected light decreases.

According to a seventeenth aspect of the present invention, in the configuration of the ninth to fifteenth aspects, the first step comprises three rows of monitor masks each including a plurality of the monitor masks on the substrate at predetermined intervals. The second step includes irradiating the three or more monitoring mask rows with light and monitoring the intensities of diffracted light from the three or more monitoring mask rows. The configuration is added that includes a step of terminating the etching of the substrate when the light intensity decreases.

The present invention provides a method of manufacturing a field emission type electron source for forming a gate electrode having a predetermined first diameter on a conductive substrate. A first step of forming an etching mask and a monitoring mask having a second diameter smaller than the first diameter by a predetermined dimension difference not more than the minimum exposure dimension; and forming the etching mask on the conductive substrate. Using a mask and a monitoring mask, etching is performed until the three-dimensional structure formed below the monitoring mask no longer supports the monitoring mask, thereby forming a top surface having a diameter corresponding to the predetermined dimensional difference. A second step of forming a cathode having, and sequentially depositing an insulating film and a metal film on the conductive substrate by using the etching mask to form a cathode on a peripheral portion of the cathode on the conductive substrate. A third step of forming a gate electrode insulated from the conductive substrate by an insulating film; and a fourth step of removing the etching mask remaining on the cathode. .

According to a nineteenth aspect of the present invention, in the configuration of the eighteenth aspect, in the fourth step, the tip of the cathode is sharpened by performing wet etching on a side surface of the cathode, and This is an additional step of removing the etching mask remaining above.

According to a twentieth aspect of the present invention, in the configuration of the eighteenth aspect, in the fourth step, a predetermined chemical reaction is caused on the side surface of the cathode, and the side surface has a composition different from the original composition. After the thin film is formed, the thin film is removed by etching, thereby sharpening the tip of the cathode and removing the etching mask remaining on the cathode.

According to a twenty-first aspect of the present invention, in the constitution of the eighteenth aspect, the fourth step is such that an oxide film is formed on the side surface by performing a thermal oxidation process on the side surface of the cathode. By removing the oxide film by etching, the tip of the cathode is sharpened and the etching mask remaining on the cathode is removed.

According to a twenty-second aspect of the present invention, in addition to the configuration of the twenty-first aspect, a configuration is provided in which the conductive substrate is made of silicon or a silicon compound, and the oxide film is a silicon oxide film.

According to a twenty-third aspect of the present invention, in addition to the configuration of the eighteenth to twenty-second aspects, the configuration in which the etching in the second step is dry etching or wet etching accompanied by side etching is added.

According to a twenty-fourth aspect of the present invention, in the configuration of the eighteenth to twenty-second aspects, the second step is a step of performing dry etching on the conductive substrate using the etching mask and the monitoring mask. After forming a three-dimensional structure consisting of convex portions protruding from the surface of the conductive substrate,
A step of forming a cathode having a top surface having a diameter corresponding to the predetermined dimensional difference by performing wet etching on the side surface of the three-dimensional structure until the three-dimensional structure no longer supports the monitoring mask. Is added.

According to a twenty-fifth aspect of the present invention, in the configuration of the eighteenth to twenty-fourth aspects, the second step includes irradiating the monitor mask with light and monitoring the intensity of light reflected from the monitor mask. A structure is added in which the etching of the conductive substrate is terminated when the intensity of the reflected light decreases.

According to a twenty-sixth aspect of the present invention, in the configuration of the eighteenth to twenty-fourth aspects, the first step is such that a monitor mask row including a plurality of the monitor masks is formed on the conductive substrate at predetermined intervals. Forming at least three rows, the second step irradiating light to the three or more monitoring mask rows and monitoring the intensity of diffracted light from the three or more monitoring mask rows; A configuration is added that includes a step of terminating etching of the conductive substrate when the intensity of the diffracted light decreases.

[0044]

According to the structure of the first aspect, the first diameter of the three-dimensional structure to be etched is larger than the second diameter of the three-dimensional structure for monitoring by a predetermined dimension difference. If etching is performed on each side surface of the body until the three-dimensional structure for monitoring disappears, the diameter of the fine three-dimensional structure becomes a predetermined size difference equal to or smaller than the minimum exposure size when the etching is completed.

According to the second aspect of the present invention, the three-dimensional structure to be etched and the three-dimensional structure for monitoring are linear or dot-like, respectively, and the fine three-dimensional structure is a linear or dot-like etching mask. Therefore, it is possible to obtain a linear or dot-shaped etching mask having a predetermined dimension difference equal to or smaller than the minimum exposure dimension.

According to the third aspect of the present invention, the point in time at which the intensity of the reflected light from the three-dimensional structure for monitoring decreases coincides with the point in time when the three-dimensional structure for monitoring disappears. Etching on the side surface of the three-dimensional structure to be etched can be surely completed.

According to the fourth aspect of the present invention, the point in time at which the intensity of the diffracted light from the monitoring three-dimensional structure decreases coincides with the point in time at which the three-dimensional structure to be etched disappears. Etching on the side surface of the three-dimensional structure to be etched can be surely completed. In this case, in order to monitor the intensity of diffracted light from three or more monitoring three-dimensional structure rows arranged at predetermined intervals,
The intensity of the diffracted light is greater than the intensity of the reflected light, and it is possible to reliably detect the point at which the three-dimensional structure for monitoring disappears.

According to the fifth aspect of the present invention, the first diameter of the first three-dimensional structure to be etched is larger than the third diameter of the three-dimensional structure for monitoring by the second predetermined dimension difference, and the second to-be-etched structure is formed. Since the second diameter of the three-dimensional structure is larger than the first diameter of the first three-dimensional structure to be etched by the first predetermined dimension difference, the first and second three-dimensional structures to be etched and the three-dimensional structure for monitoring are provided. When etching is performed on each side of the body until the three-dimensional structure for monitoring disappears, at the time when the etching is completed, the diameter of the first fine three-dimensional structure becomes a second predetermined size difference smaller than the minimum exposure size. The difference between the diameter of the second micro three-dimensional structure and the diameter of the first micro three-dimensional structure is a first predetermined dimensional difference.

According to the structure of claim 6, since the first microscopic three-dimensional structure and the second microscopic three-dimensional structure are each a linear or dot-like etching mask, the second predetermined size smaller than the minimum exposure size is used. A linear or dot-shaped first etching mask having a diameter corresponding to the difference and a linear or dot-shaped second having a diameter larger by a first predetermined dimension difference than the diameter of the first etching mask; Can be obtained.

According to the seventh aspect of the present invention, the point in time at which the intensity of the reflected light from the three-dimensional structure for monitoring decreases coincides with the point in time when the three-dimensional structure for monitoring disappears. Etching on the side surfaces of the first and second three-dimensional structures to be etched can be reliably completed.

According to the eighth aspect, the time when the intensity of the diffracted light from the three-dimensional structure for monitoring decreases coincides with the time when the three-dimensional structure for monitoring disappears. Etching on the side surfaces of the first and second three-dimensional structures to be etched can be reliably completed. In this case, since the intensity of the diffracted light from the three or more monitoring three-dimensional structure rows arranged at predetermined intervals is monitored, the intensity of the diffracted light is greater than the intensity of the reflected light. The point at which the body disappears can be reliably detected.

According to the ninth aspect of the present invention, the first diameter of the etching mask is larger than the second diameter of the monitoring mask by a predetermined dimension difference. When the etching is performed until disappears or separates from the monitoring mask, a fine three-dimensional structure having a diameter corresponding to a predetermined dimensional difference equal to or smaller than the minimum exposure dimension is provided below the etching mask at the time when the etching is completed. It is formed.

According to the tenth aspect of the present invention, since the monitor mask and the etching mask are each linear or dot-shaped, a linear or dot-shaped microscopic solid having a diameter corresponding to a predetermined dimensional difference equal to or smaller than the minimum exposure dimension. A structure can be formed.

According to the eleventh aspect, after a predetermined chemical reaction is caused on the side surface of the fine three-dimensional structure to form a thin film having a composition different from the original composition on the side surface, the thin film is removed. The diameter of the fine three-dimensional structure is smaller than the predetermined dimension difference equal to or smaller than the minimum exposure dimension by twice the thickness of the thin film.

According to the twelfth aspect of the present invention, the substrate is made of a material having a composition different from the original composition by a predetermined chemical reaction and a thin film which is selectively etched by a specific solution. The thin film formed on the side surface can be reliably removed by wet etching with a specific solution.

According to the structure of claim 13, the composition of the substrate is silicon and the composition of the thin film is silicon oxide.
Formation of the thin film and removal of the thin film are easy.

According to the structure of the fourteenth aspect, the etching in the second step is dry etching or wet etching accompanied by side etching, so that etching is surely performed on the substrate below the etching mask and the monitoring mask. Can do it.

According to the structure of the fifteenth aspect, the three-dimensional structure is formed on the side surface of the three-dimensional structure comprising the convex portions formed by performing dry etching on the substrate using the etching mask and the monitoring mask. When the wet etching is performed until the support mask is no longer supported, a fine three-dimensional structure having a top surface having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension can be formed.

According to the structure of the sixteenth aspect, the point in time when the intensity of the reflected light from the monitor mask decreases coincides with the point in time when the monitor mask disappears. Can be terminated.

According to the seventeenth aspect, the point in time at which the intensity of the diffracted light from the monitor mask decreases coincides with the point in time at which the monitor mask disappears. Can be terminated. In this case, since the intensity of the diffracted light from three or more monitoring mask rows arranged at predetermined intervals is monitored, the intensity of the diffracted light is greater than the intensity of the reflected light, and the time when the monitoring mask disappears Can be reliably detected.

According to the eighteenth aspect, the first diameter of the etching mask is larger than the second diameter of the monitor mask by a predetermined dimension difference, so that the etching is performed on the conductive substrate until the monitor mask disappears. Is performed, when the etching is completed, a cathode having a top surface having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension is formed below the etching mask.

According to the structure of claim 19, the fourth step is:
If the tip of the cathode is sharpened by performing wet etching on the side surface of the cathode, the etching mask remaining on the cathode is not supported by the tip of the cathode and is removed.

According to the twentieth aspect, a step of forming a thin film having a composition different from the original composition on a side surface of the cathode by a predetermined chemical reaction and removing the thin film by etching to sharpen the tip of the cathode. Further, the step of removing the etching mask remaining on the cathode can be reliably performed.

According to the structure of the twenty-first aspect, after forming an oxide film on the side surface of the cathode by thermal oxidation and removing the oxide film by etching, if the tip of the cathode is sharpened, it remains in the process and on the cathode. The step of removing the etching mask to be performed can be reliably performed.

According to the structure of claim 22, since the conductive substrate is made of silicon or a silicon compound and the oxide film is a silicon oxide film, the step of removing the oxide film by etching can be easily performed.

According to the structure of the twenty-third aspect, the etching in the second step is dry etching or wet etching accompanied with side etching, so that the conductive substrate below the etching mask and the monitoring mask is surely etched. Can be performed.

According to a twenty-fourth aspect of the present invention, the three-dimensional structure is formed on a side surface of a three-dimensional structure formed of a convex portion formed by performing dry etching on the conductive substrate using an etching mask and a monitoring mask. If the wet etching is performed until the substrate no longer supports the monitoring mask, a cathode having a top surface having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension can be formed.

According to the structure of the twenty-fifth aspect, the point in time when the intensity of the reflected light from the monitor mask decreases coincides with the point in time when the monitor mask disappears. The process can be reliably terminated.

According to the twenty-sixth aspect, the point in time at which the intensity of the diffracted light from the monitor mask decreases coincides with the point in time at which the monitor mask disappears. The process can be reliably terminated. In this case, since the intensity of the diffracted light from three or more monitoring mask rows arranged at predetermined intervals is monitored, the intensity of the diffracted light is greater than the intensity of the reflected light, and the time when the monitoring mask disappears Can be reliably detected.

[0070]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 (a) to 1 (c), 2 (a) and 2 (b) show respective steps of a method for manufacturing a quantum wire to which the microstructure forming method according to the first embodiment of the present invention is applied. ing.

First, as shown in FIG. 1A, a silicon single crystal film 1 having a thickness of several nm was formed on a silicon substrate 3 with a silicon oxide film 2 interposed therebetween. A silicon oxide film 4 is further formed on the surface of the substrate by a thermal oxidation method.

Next, as shown in FIG. 1 (b), by performing normal photolithography on the silicon oxide film 2, a linear first three-dimensional structure to be etched having a predetermined width (w) is obtained. Body 5A, a monitor three-dimensional structure 6A having a width (w-s) smaller than the predetermined width (w) by a first predetermined dimension difference (s) smaller than the minimum exposure dimension, and the predetermined width (w) ), A linear second etched three-dimensional structure 7A having a width (w + d) larger by a second predetermined dimensional difference (d) is formed.

Next, as shown in FIG. 1C, the first and second three-dimensional structures 5A and 7A to be etched are etched with hydrofluoric acid.
When etching is performed on A and the monitoring three-dimensional structure 6A, the first and second etched three-dimensional structures 5A,
Since the surface including the side surfaces of the structure 7A and the monitoring structure 6A is etched, the first and second structures 5 to be etched are formed.
The height and width of A, 7A and the monitoring structure 6A decrease uniformly.

Next, as shown in FIG. 2A, when the etching is terminated when the monitoring structure 6A disappears,
The first structure 5A to be etched becomes a linear first etching mask 5B as a first micro three-dimensional structure having a width corresponding to a first predetermined dimensional difference (s), and a second etching mask 5B. The structure 6A to be etched has a linear shape as a second micro three-dimensional structure having a width (s + d) corresponding to the sum of the first predetermined dimensional difference (d) and the second predetermined dimensional difference (s). 2 becomes the etching mask 7B.

Next, as shown in FIG. 2B, when the silicon single crystal film 1 is dry-etched using the first and second etching masks 5B and 7B, the silicon single crystal film 1 is etched under the first etching mask 5B. A first quantum wire 8 made of a silicon single crystal having a width corresponding to a first predetermined dimensional difference (s) is formed on the side, and a second etching mask 7B is formed.
On the lower side, a second quantum wire 9 made of silicon single crystal having a width (s + d) corresponding to the sum of the first predetermined dimensional difference (s) and the second predetermined dimensional difference (d) is formed. Is done.

As described above, according to the microstructure forming method according to the first embodiment, the first quantum wire 8 having a width (s) smaller than the minimum exposure dimension, and The second quantum wires 9 each having a width (s + d) larger by a second predetermined dimension difference (d) can be formed. In this case, the width of the first and second quantum wires 8, 9 is
It is determined by the accuracy of the photomask. For example, even if exposure is performed using ultraviolet rays (g-line) having a minimum exposure dimension of about 500 nm, a quantum wire having a width of several nm to several tens nm can be obtained. it can.

Although not shown, each side surface of the first and second quantum wires 8 and 9 is subjected to a thermal oxidation oxidation treatment to obtain a side surface of the first and second quantum wires 8 and 9. After the silicon oxide film is formed in the portion and the silicon oxide film is removed, a quantum wire having a smaller width can be formed.

FIGS. 3 (a) to 3 (c) and FIGS. 4 (a) to 4 (c)
Shows the steps of the first method of manufacturing the field emission electron source according to the second embodiment of the present invention.

First, as shown in FIG. 3A, a silicon oxide film 12 is formed on the surface of a silicon substrate 11 as a conductive substrate by thermal oxidation, and then, as shown in FIG. By performing normal photolithography on the film 12, a circular etching mask 13 having a predetermined diameter (w), and a diameter (s) smaller than the predetermined diameter (w) by a predetermined dimensional difference (s). w-
The circular monitoring masks 14 having s) are respectively formed.

Next, as shown in FIG. 3C, dry etching is performed on the silicon substrate 11 using the etching mask 13 and the monitoring mask 14 under conditions that cause side etching. A first three-dimensional structure 15 and a second three-dimensional structure 16 having a conical shape or a truncated conical shape are formed below the mask 13 and the monitoring mask 14, respectively. Then, dry etching in which side etching occurs proceeds, and the second three-dimensional structure 16 is formed.
Ends the dry etching when the monitor mask 14 comes off because the monitor mask 14 is no longer supported.
When the dry etching is completed when the monitoring mask 14 is detached, the diameter of the top surface of the first three-dimensional structure 15 below the etching mask 13 corresponds to a predetermined dimensional difference (s).

Next, as shown in FIG. 4A, a heat treatment is performed on the side surface of the first three-dimensional structure 15 so that the film thickness of the half of the predetermined dimensional difference (s) is reduced on the side surface. By forming the silicon oxide film 17 having the first three-dimensional structure 15
The cathode 18 having a sharp tip shape is formed inside the substrate.

Next, as shown in FIG. 4B, when an insulating film 19 and a metal 20 A for forming a gate electrode are sequentially deposited on the silicon substrate 11, the etching mask 13 is present on the cathode 18. Therefore, the insulating film 19 and the gate electrode forming metal 20A are not deposited on the surface of the cathode 18.

Next, as shown in FIG. 4C, the etching mask 13 and the silicon oxide film 17 on the surface of the cathode 18 are dissolved by using hydrofluoric acid, so that the silicon oxide on the side surface of the cathode 18 is dissolved. When the film 17 is removed to expose the cathode 18 made of silicon, a field emission electron source including the cathode 18 and the gate electrode 20B having a circular opening is obtained.

Also in the second embodiment, similarly to the first embodiment, it is possible to realize the cathode 18 having a top surface having a diameter corresponding to a predetermined difference (s) smaller than the minimum exposure size. In addition, the cathode 18
By forming the silicon oxide film 17 on the side surface and removing the silicon oxide film 17, it is possible to form a field emission type electron source having a cathode 18 having a steep tip with good reproducibility.

In the second embodiment, in order to form the cathode 18, dry etching which causes side etching is used as the etching.
In addition to wet etching, dry etching and anisotropic wet etching may be used in combination.

FIGS. 5 (a) to 5 (d) and FIGS. 6 (a) and 6 (b) show each step of the second method for manufacturing a field emission type electron beam according to the third embodiment of the present invention. I have.

First, as shown in FIG. 5A, a silicon oxide film 22 is formed on the (100) plane of the silicon crystal substrate 21 by thermal oxidation, and then, as shown in FIG. 22 is subjected to ordinary photolithography to obtain a circular etching mask 23 having a predetermined diameter (w), and a diameter (ws) smaller than the predetermined diameter (w) by a predetermined dimension difference (s). Are formed respectively.

Next, as shown in FIG. 5C, dry etching is performed on the silicon crystal substrate 21 under the condition that side etching does not occur, so that a first columnar shape is formed below the etching mask 23. And a columnar second member 25 under the monitor mask 24.
Is formed.

Next, as shown in FIG. 5D, anisotropic etching is performed on the side surfaces of the columnar first and second three-dimensional structures 25 and 26 to obtain the first and second three-dimensional structures. Body 25,
A surface including the (111) plane of the silicon crystal substrate 21 is exposed on the side surface of the substrate 26, and a lower portion 27 a having a truncated cone shape and an upper portion 27 b having an inverted truncated cone shape whose top portions are connected to each other below the etching mask 23. A first drum-shaped body 27 is formed, and a second drum-shaped having a truncated cone-shaped lower part 28a and an inverted truncated cone-shaped upper part 28b whose tops are connected to each other below the monitoring mask 24. A body 28 is formed. And the first
As the anisotropic etching of the second drum-shaped bodies 27 and 28 proceeds, the diameter of the connection portion of the second drum-shaped body 28 gradually decreases, and the upper part 28b of the second drum-shaped body 28 is used for monitoring. Since it is separated from the lower part 28a of the second drum-shaped body 28 with the etching mask 24 attached, at this point, the anisotropic etching for the first and second drum-shaped bodies 27, 28 is completed. At this point, the diameter of the connecting portion between the lower part 27a and the upper part 27b of the first drum-shaped body 27 has a predetermined dimensional difference (s).

Next, as shown in FIG. 6A, the silicon crystal substrate 21 is subjected to a thermal oxidation treatment, so that the surface of the silicon crystal substrate 21 and the side surface of the first drum 27 are formed. When the silicon oxide film 29 having a thickness of about half of the predetermined dimensional difference (s) is formed, the lower portion 2 of the first drum-shaped body 27 is formed.
A cathode 30 having a sharp tip is formed inside 7b. Then, the insulating film 3 is formed on the silicon crystal substrate 21.
1 and the gate electrode forming metal 32A are sequentially deposited,
Since the etching mask 23 exists on the cathode 18, the insulating film 31 and the gate electrode forming metal 32 </ b> A are not deposited on the surface of the cathode 18.

Next, as shown in FIG. 6B, when the silicon oxide film 29 is removed by etching to expose the cathode 30 made of silicon, the cathode 30 and the gate electrode 32B having a circular opening are formed. Is obtained.

As described in the second and third embodiments, on the same substrate, the etching mask and the monitoring mask having a diameter smaller than the diameter of the etching mask by a predetermined dimension difference smaller than the minimum exposure dimension. After the substrate is formed, the substrate is etched using an etching mask and a monitoring mask, whereby a fine three-dimensional structure having a diameter equal to or smaller than the minimum exposure dimension can be formed. Further, by using the above-mentioned micro three-dimensional structure as a cathode of a field emission type electron source, a cathode having a sharp tip can be easily formed.

In the second and third embodiments, silicon is used as the material of the substrate, that is, the cathode, but the material of the substrate is not necessarily limited to silicon.

In the second and third embodiments,
A thermal oxidation process is performed on the side surface of the micro three-dimensional structure to form a thermal oxide film, and the thermal oxide film is removed by etching to sharpen the tip of the cathode, but the thermal oxide film is not necessarily formed. After forming the gate electrode, the side surface of the fine three-dimensional structure may be further etched to form the tip of the cathode.

Hereinafter, in the first to third embodiments,
When the etching is completed, that is, when the monitoring structure 6A disappears in the first embodiment, the second three-dimensional structure 16 does not support the monitoring mask 14 in the second embodiment, and the monitoring mask 14 is removed. At the time of release,
Or, in the third embodiment, the upper part 28b of the second drum-shaped body 28
A method of observing the point at which the light beam separates from the lower portion 28a of the second drum-shaped body 28 by using the light diffraction phenomenon will be described.

FIG. 7 shows an etching mask formation region 41 formed on the substrate 40 and a monitor mask formation region 42 formed near the etching mask formation region 41 on the substrate 40, respectively. In addition, a circular etching mask 43 is formed in a matrix in the etching mask forming region 41, and a circular monitoring mask 44 is formed in a matrix in the monitoring mask forming region 42. A laser beam 45 made of helium neon is applied to the monitor mask forming region 42, and the intensity of the diffracted light 46 from the matrix-like etching mask 43 is detected by a photodetector 47. The substrate 40 below the monitor mask 43 is etched, and the monitor mask 43 is
When the substrate 40 is no longer supported by zero and separates from the substrate 40, the intensity of the diffracted light 46 starts to decrease sharply. At that point, the etching of the substrate 40 ends.

In the above case, the point at which the monitor mask is removed is observed by using the light diffraction phenomenon.
5 and a matrix-like etching mask 43
The intensity of the reflected light from the substrate 40 may be detected by a photodetector, and the etching of the substrate 40 may be terminated at the time when the intensity of the reflected light starts to decrease sharply.

[0099]

According to the microstructure forming method of the present invention, the first diameter of the three-dimensional structure to be etched is larger than the second diameter of the three-dimensional structure for monitoring by a predetermined dimension difference. By etching each side of the etched three-dimensional structure and the three-dimensional structure for monitoring until the three-dimensional structure for monitoring disappears, a fine three-dimensional structure having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension is formed. Therefore, it is possible to form a fine three-dimensional structure having a diameter in a submicron region equal to or smaller than the minimum exposure dimension by an inexpensive ultraviolet exposure method.

According to the method for forming a microstructure according to the second aspect of the present invention, since the fine three-dimensional structure is a linear or dot-shaped etching mask, the etching mask having a diameter of a submicron region smaller than the minimum exposure dimension. Can be formed by an inexpensive ultraviolet exposure method.

According to the method of forming a microstructure according to the third aspect of the present invention, the point in time when the intensity of the reflected light from the three-dimensional structure for monitoring decreases coincides with the point in time when the three-dimensional structure for monitoring disappears. Since the etching on the side surface of the three-dimensional structure to be etched can be surely terminated when the structure disappears, a fine three-dimensional structure having a diameter equal to or less than the minimum exposure dimension can be accurately formed.

According to the method of forming a microstructure according to the fourth aspect of the present invention, since the diffracted light having a large intensity from three or more monitor three-dimensional structure rows arranged at predetermined intervals is monitored, Since the time point at which the three-dimensional structure disappears can be reliably detected, a fine three-dimensional structure having a diameter equal to or smaller than the minimum exposure dimension can be accurately formed.

According to the microstructure forming method of the fifth aspect, the first diameter of the first three-dimensional structure to be etched is larger than the third diameter of the three-dimensional structure for monitoring by a second predetermined size difference. The first and second three-dimensional structures to be etched are larger because the second diameter of the second three-dimensional structure to be etched is greater than the first diameter of the first three-dimensional structure to be etched by a first predetermined dimension difference. By etching each side of the structure and the three-dimensional structure for monitoring until the three-dimensional structure for monitoring disappears, a first fine structure having a diameter corresponding to a first predetermined dimension difference equal to or smaller than the minimum exposure dimension is obtained. A three-dimensional structure and a second micro three-dimensional structure having a diameter larger by a second predetermined dimension difference than the first micro three-dimensional structure can be formed by an inexpensive ultraviolet exposure method.

According to the method of forming a microstructure according to the sixth aspect of the present invention, the first microscopic three-dimensional structure and the second microscopic three-dimensional structure are linear or dot-shaped etching masks, respectively. A linear or dot-shaped first etching mask having a diameter corresponding to the following second predetermined dimension difference, and a line having a diameter larger by a first predetermined dimension difference than the diameter of the first etching mask Thus, a second etching mask in the shape of a dot or a dot can be obtained.

According to the microstructure forming method of the present invention, the point in time when the intensity of the reflected light from the three-dimensional structure for monitoring is reduced coincides with the point in time when the three-dimensional structure for monitoring disappears. Since the etching on the side surfaces of the first and second three-dimensional structures to be etched can be surely finished at the time when the structure disappears, a line having a diameter corresponding to a second predetermined size difference equal to or smaller than the minimum exposure size. It is possible to accurately form a linear or dot-shaped first etching mask and a linear or dot-shaped second etching mask having a diameter larger by a first predetermined dimension difference than the first etching mask.

According to the microstructure forming method of the present invention, since the diffracted light having a large intensity from three or more monitoring three-dimensional structure rows arranged at predetermined intervals is monitored, Since the time point at which the three-dimensional structure disappears can be reliably detected, the first micro three-dimensional structure having a diameter equal to or less than the minimum exposure dimension and the second having a diameter larger than the first micro three-dimensional structure by a predetermined size difference. A fine three-dimensional structure can be formed more accurately.

According to the microstructure forming method of the ninth aspect of the present invention, the first diameter of the etching mask is larger than the second diameter of the monitoring mask by a predetermined dimensional difference. By performing etching until the lower three-dimensional structure disappears or separates from the monitor mask, a fine three-dimensional structure having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension is formed below the etching mask. Therefore, it is possible to form a fine three-dimensional structure having a diameter in a submicron region equal to or smaller than the minimum exposure dimension by an inexpensive ultraviolet exposure method.

According to the method for forming a microstructure according to the tenth aspect of the present invention, since the planes of the monitoring mask, the etching mask and the microstructure are linear or dot-shaped, respectively, the difference in the predetermined dimension is smaller than the minimum exposure dimension. It becomes possible to form a linear or dot-shaped fine three-dimensional structure having a corresponding diameter by an inexpensive ultraviolet exposure method.

According to the method for forming a microstructure according to the eleventh aspect, after a predetermined chemical reaction is caused on the side surface of the micro three-dimensional structure to form a thin film having a composition different from the original composition on the side surface. In order to remove the thin film, the diameter of the fine three-dimensional structure is smaller by twice the thickness of the thin film than the predetermined dimensional difference equal to or smaller than the minimum exposure dimension. It is possible to form a fine three-dimensional structure having

According to the microstructure forming method according to the twelfth aspect of the present invention, the substrate is made of a material having a composition different from the original composition by a predetermined chemical reaction and forming a thin film selectively etched by a specific solution. Therefore, the thin film formed on the side surface of the fine three-dimensional structure can be surely removed by wet etching with a specific solution, so that the fine three-dimensional structure having a diameter smaller than a predetermined dimension difference equal to or smaller than the minimum exposure dimension. Can be reliably formed.

According to the method of forming a microstructure according to the thirteenth aspect of the present invention, the composition of the substrate is silicon and the composition of the thin film is silicon oxide. A fine three-dimensional structure having a diameter smaller than a predetermined dimension difference equal to or smaller than the exposure dimension can be more reliably formed.

According to the microstructure forming method of the present invention, since the etching in the second step is dry etching or wet etching accompanied by side etching, the substrate below the etching mask and the monitoring mask is etched. Therefore, a fine three-dimensional structure having a diameter equal to or smaller than the minimum exposure dimension can be surely formed by an inexpensive ultraviolet light exposure method.

According to the method for forming a microstructure according to the fifteenth aspect, the side surface of the three-dimensional structure composed of the convex portions formed by performing dry etching on the substrate using the etching mask and the monitoring mask. In order to perform wet etching until the three-dimensional structure no longer supports the monitor mask, a fine three-dimensional structure having a top surface having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension is reliably formed by an inexpensive ultraviolet exposure method. It can be formed.

According to the method for forming a microstructure according to the sixteenth aspect of the present invention, the point in time when the intensity of the reflected light from the monitor mask decreases coincides with the point in time when the monitor mask disappears.
Since etching of the substrate can be surely terminated at the time when the monitoring mask disappears, a fine three-dimensional structure having a diameter corresponding to a predetermined dimension difference equal to or smaller than the minimum exposure dimension can be accurately formed.

According to the method for forming a fine structure according to the seventeenth aspect of the present invention, since the diffracted light having a large intensity from three or more monitor mask rows arranged at a predetermined interval is monitored, the monitor mask is used. Since the disappearance point can be reliably detected, a fine three-dimensional structure having a diameter equal to or smaller than the minimum exposure dimension can be formed more accurately.

According to the method for manufacturing a field emission electron source according to the eighteenth aspect of the present invention, the first diameter of the etching mask is larger than the second diameter of the monitoring mask by a predetermined dimension difference. By performing etching until the monitor mask disappears, a cathode having a top surface having a diameter corresponding to a predetermined dimensional difference equal to or smaller than the minimum exposure dimension can be formed under the etching mask. A cathode having a top surface with a diameter equal to or smaller than the exposure dimension can be formed by an inexpensive ultraviolet exposure method.

According to the method for manufacturing a field emission type electron source according to the nineteenth aspect of the present invention, in the fourth step, the tip of the cathode is sharpened by performing wet etching on the side surface of the cathode, and In order to remove the remaining etching mask, the step of sharpening the tip of the cathode and the step of removing the etching mask can be performed simultaneously.

According to the method of manufacturing a field emission electron source according to the twentieth aspect of the invention, after forming a thin film having a composition different from the original composition on a side surface of the cathode by a predetermined chemical reaction,
Since the thin film is removed by etching, the step of sharpening the tip of the cathode and the step of removing the etching mask remaining on the cathode can be performed simultaneously and reliably.

According to the method of manufacturing a field emission electron source according to the twenty-first aspect of the present invention, an oxide film is formed on the side surface of the cathode by thermal oxidation, and the oxide film is removed by etching. When the portion is sharpened, the step and the step of removing the etching mask remaining on the cathode can be performed simultaneously and reliably.

According to the method of manufacturing a field emission electron source according to the present invention, the conductive substrate is made of silicon or a silicon compound, and the oxide film is a silicon oxide film. Therefore, the oxide film is easily removed by etching. So you can
The step of sharpening the tip of the cathode and the step of removing the etching mask remaining on the cathode can be performed easily and reliably at the same time.

According to the method of manufacturing a field emission type electron source according to the twenty-third aspect of the present invention, the etching in the second step is dry etching or wet etching accompanied by side etching. Since the etching can be reliably performed on the conductive substrate on the side, a cathode having a top surface having a diameter equal to or smaller than the minimum exposure dimension can be surely formed by an inexpensive ultraviolet exposure method.

According to the method of manufacturing a field emission type electron source according to the twenty-fourth aspect of the present invention, the convex portion formed by performing dry etching on the conductive substrate using the etching mask and the monitoring mask is used. In order to perform wet etching on the side of the three-dimensional structure until the three-dimensional structure no longer supports the monitoring mask, a cathode having a top surface having a diameter corresponding to a predetermined dimensional difference equal to or less than the minimum exposure size is exposed to an inexpensive ultraviolet light exposure method. Thus, it is possible to form it more reliably.

According to the method of manufacturing a field emission type electron source according to the twenty-fifth aspect of the present invention, the point in time when the intensity of the reflected light from the monitor mask decreases coincides with the point in time when the monitor mask disappears. Since the etching on the conductive substrate can be surely terminated at the time when disappears, the cathode having the top surface having the diameter corresponding to the predetermined dimension difference equal to or smaller than the minimum exposure dimension can be accurately formed.

According to the method of manufacturing a field emission type electron source according to the twenty-sixth aspect, to monitor diffracted light having a large intensity from three or more monitoring mask rows arranged at predetermined intervals, Since the time point at which the monitor mask disappears can be reliably detected, a cathode having a top surface with a diameter smaller than the minimum exposure dimension can be formed more accurately.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing each step of a method for manufacturing a quantum wire to which a microstructure forming method according to a first embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view showing each step of a method of manufacturing a quantum wire to which a microstructure forming method according to a first embodiment of the present invention is applied.

FIG. 3 is a sectional view showing each step of a first method for manufacturing a field emission electron source according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing each step of a first method for manufacturing a field emission electron source according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing each step of a second method for manufacturing a field emission electron source according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing each step of a second method for manufacturing a field emission electron source according to a third embodiment of the present invention.

FIG. 7 is a perspective view for explaining a method of observing the timing of ending the etching in the first to third embodiments of the present invention.

FIG. 8 is a cross-sectional view showing each step of a method for manufacturing a quantum wire to which a conventional microstructure forming method is applied.

FIG. 9 is a cross-sectional view showing each step of a method for manufacturing a quantum wire to which a conventional microstructure forming method is applied.

FIG. 10 is a cross-sectional view showing each step of a first conventional example of a method for manufacturing a field emission electron source.

FIG. 11 is a cross-sectional view showing each step of a first conventional example of a method for manufacturing a field emission electron source.

FIG. 12 is a sectional view showing each step of a second conventional example of a method for manufacturing a field emission electron source.

FIG. 13 is a cross-sectional view showing each step of a second conventional example of a method for manufacturing a field emission electron source.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 silicon single crystal film 2 silicon oxide film 3 silicon substrate 4 silicon oxide film 5A first etching mask 5B first micro three-dimensional structure 6A second etching mask 7A monitoring mask 7B second micro three-dimensional structure Reference Signs List 8 first quantum wire 9 second quantum wire 11 silicon substrate 12 silicon oxide film 13 etching mask 14 monitoring mask 15 first fine three-dimensional structure 16 second fine three-dimensional structure 17 silicon oxide film 18 cathode 19 Insulating film 20A Gate electrode forming metal 20B Gate electrode 21 Silicon substrate 22 Silicon oxide film 23 Etching mask 24 Monitor mask 25 First fine three-dimensional structure 26 Second fine three-dimensional structure 27 First drum-shaped body 28 Second drum-shaped body 29 Silicon oxide film 30 Cathode 31 Insulating film 32A Gate electrode Pole forming metal 32B Gate electrode 40 Substrate 41 Etching mask formation area 42 Monitor mask formation area 43 Etching mask 44 Monitor mask 45 Laser light 46 Diffracted light 47 Photodetector

Claims (26)

(57) [Claims] 1. A three-dimensional structure to be etched having a first diameter of a predetermined size on a substrate, and a three-dimensional structure to be etched having a minimum exposure dimension smaller than the first diameter and determined by the accuracy of a photomask.
A first step of forming a three-dimensional structure for monitoring having a second diameter smaller by a predetermined dimension difference; and the three-dimensional structure for monitoring with respect to each side surface of the three-dimensional structure to be etched and the three-dimensional structure for monitoring. A second step of forming a micro three-dimensional structure having a diameter corresponding to the predetermined dimensional difference on the substrate by performing etching until the body disappears. Forming method. 2. The planar structure of each of the three-dimensional structure to be etched and the three-dimensional structure for monitoring is linear or dot-like, and the fine three-dimensional structure is a linear or dot-like etching mask. The method for forming a microstructure according to claim 1, wherein 3. The step of irradiating the three-dimensional structure for monitoring with light and monitoring the intensity of light reflected from the three-dimensional structure for monitoring, and the intensity of the reflected light rapidly decreases in the second step.
The microstructure forming method according to claim 1, further comprising a step of terminating etching of a side surface of the three-dimensional structure to be etched at a time when the etching is performed. 4. The method according to claim 1, wherein the first step includes a step of forming three or more rows of the three-dimensional monitor structure including a plurality of the three-dimensional monitor structures on the substrate at predetermined intervals. The step of irradiating the three or more monitoring three-dimensional structure rows with light and monitoring the intensity of the diffracted light from the three or more monitoring three-dimensional structure rows;
3. The microstructure forming method according to claim 1, further comprising a step of terminating etching of a side surface of the three-dimensional structure to be etched at a time when the three-dimensional structure is sharply lowered . 5. A first etched three-dimensional structure having a first diameter of a predetermined size and a second diameter larger by a first predetermined size difference than the first diameter on a substrate. Having a second
Is determined by the accuracy of the photomask, which is smaller than or equal to the minimum exposure dimension than the first diameter.
A first step of forming a monitor three-dimensional structure having a third diameter smaller by a second predetermined dimension difference, the first three-dimensional structure to be etched, the second three-dimensional structure to be etched, and a monitor A first fine three-dimensional structure having a diameter corresponding to the second predetermined dimensional difference on the substrate by etching each side surface of the three-dimensional structure for monitoring until the three-dimensional structure for monitoring disappears A second micro three-dimensional structure forming a body and a second micro three dimensional structure having a diameter larger by the first predetermined dimensional difference than the diameter of the first micro three dimensional structure;
And a step of forming a microstructure. 6. The first micro three-dimensional structure, wherein the first three-dimensional structure to be etched, the second three-dimensional structure to be etched, and the three-dimensional structure for monitoring are linear or dot-shaped, respectively. The method for forming a fine structure according to claim 5, wherein the second micro three-dimensional structure is a linear or dot-like etching mask, respectively. 7. The second step includes irradiating the monitor three-dimensional structure with light and monitoring the intensity of light reflected from the monitor three-dimensional structure, and the intensity of the reflected light rapidly decreases.
Wherein at the time of the first object to be etched steric structure and a second
7. A step of terminating the etching of each side surface of the three-dimensional structure to be etched.
3. The method for forming a microstructure according to item 1. 8. The method according to claim 8, wherein the first step includes a step of forming three or more monitor three-dimensional structure rows each including the plurality of monitor three-dimensional structures on the substrate at predetermined intervals. The step of irradiating the three or more monitoring three-dimensional structure rows with light and monitoring the intensity of the diffracted light from the three or more monitoring three-dimensional structure rows;
7. The microstructure according to claim 5, further comprising a step of terminating the etching of each side surface of the first etched three-dimensional structure and the second etched three-dimensional structure at a time when the structure rapidly decreases. Forming method. 9. An etching mask having a first diameter of a predetermined size on a substrate, and a minimum exposure dimension smaller than the first diameter and determined by the accuracy of the photomask. A first step of forming a monitor mask having a second diameter smaller by a predetermined dimension difference; and forming the monitor mask below the monitor mask using the etching mask and the monitor mask with respect to the substrate. By performing etching until the three-dimensional structure disappears or separates from the monitor mask, a second three-dimensional structure having a diameter corresponding to the predetermined dimensional difference is formed.
And a step of forming a microstructure. 10. The microstructure forming method according to claim 9, wherein the planar shape of the monitor mask, the etching mask, and the fine three-dimensional structure is linear or dot-like, respectively. 11. The side surface of the micro three-dimensional structure formed by the second step, wherein the substrate is made of a material that forms a thin film having a composition different from the original composition on a surface thereof by a predetermined chemical reaction. Causing the predetermined chemical reaction to occur on the portion, forming a thin film having a composition different from the original composition on the side surface portion, and then removing the thin film to reduce the diameter of the fine three-dimensional structure to the predetermined dimensional difference. 10. The method according to claim 9, further comprising a third step of making the size smaller.
3. The method for forming a microstructure according to item 1. 12. The second step, wherein the substrate is made of a material having a composition different from the original composition on a surface thereof by a predetermined chemical reaction and a thin film which is selectively etched by a specific solution. The above-mentioned predetermined chemical reaction is caused on the side surface of the micro three-dimensional structure formed by the above to form a thin film having a composition different from the original composition on the side surface, and thereafter, the thin film is wetted with the specific solution. The microstructure forming method according to claim 9, further comprising a third step of reducing the diameter of the microscopic three-dimensional structure to be smaller than the predetermined dimensional difference by removing the microstructure by etching. 13. The method according to claim 11, wherein the composition of the substrate is silicon, and the composition of the thin film is silicon oxide. 14. The method according to claim 9, wherein the etching in the second step is dry etching or wet etching accompanied by side etching.
The method for forming a microstructure according to any one of the above items. 15. The three-dimensional structure comprising a convex portion protruding from the surface of the substrate by performing dry etching on the substrate using the etching mask and the monitoring mask. Forming a fine three-dimensional structure having a diameter corresponding to the predetermined dimensional difference by performing wet etching on the side surface of the three-dimensional structure until the three-dimensional structure no longer supports the monitoring mask; 10. The method according to claim 9, wherein
14. The method for forming a microstructure according to any one of the thirteenth aspect. 16. The second step includes irradiating the monitor mask with light and monitoring the intensity of the reflected light from the monitor mask, and when the intensity of the reflected light sharply decreases. The method according to any one of claims 9 to 15, further comprising the step of: terminating the etching of the substrate at a point. 17. The method according to claim 17, wherein the first step includes a step of forming three or more monitor mask rows each including the plurality of monitor masks at predetermined intervals on the substrate, and the second step includes: The three or more monitoring mask rows are irradiated with light, and the intensities of the diffracted light from the three or more monitoring mask rows are monitored, and the intensity of the diffracted light sharply decreases.
The method for forming a microstructure according to any one of claims 9 to 15, wherein the etching of the substrate is completed at a time when the substrate is lowered. 18. An etching mask for forming a gate electrode having a first diameter of a predetermined size on a conductive substrate, a mask having a minimum exposure dimension smaller than the first diameter and
A first mask for forming a monitor mask having a second diameter smaller by a predetermined dimension difference determined by the accuracy of the photomask ;
And etching the conductive substrate using the etching mask and the monitoring mask until the three-dimensional structure formed below the monitoring mask no longer supports the monitoring mask. By forming a second step of forming a cathode having a top surface having a diameter corresponding to the predetermined dimensional difference, and by sequentially depositing an insulating film and a metal film on the conductive substrate using the etching mask, Forming a gate electrode insulated from the conductive substrate by the insulating film in a peripheral portion of the cathode on the conductive substrate;
And a fourth step of removing the etching mask remaining on the cathode. A method for manufacturing a field emission electron source, comprising: 19. The fourth step is a step of sharpening a tip of the cathode and removing the etching mask remaining on the cathode by performing wet etching on a side surface of the cathode. 19. The method for manufacturing a field emission electron source according to claim 18, wherein: 20. The fourth step is to form a thin film having a composition different from the original composition on the side surface portion by causing a predetermined chemical reaction on the side surface portion of the cathode, and then removing the thin film by etching. 20. The method according to claim 18, further comprising: sharpening a tip of the cathode and removing the etching mask remaining on the cathode. 21. The fourth step, wherein an oxide film is formed on the side surface by performing a thermal oxidation treatment on the side surface of the cathode, and then the oxide film is removed by etching. 19. The method for manufacturing a field emission electron source according to claim 18, comprising a step of sharpening a tip of a cathode and removing the etching mask remaining on the cathode. 22. The method according to claim 21, wherein the conductive substrate is made of silicon or a silicon compound, and the oxide film is a silicon oxide film. 23. The etching method according to claim 18, wherein the etching in the second step is dry etching or wet etching accompanied by side etching.
3. The method for manufacturing a field emission electron source according to any one of 2. 24. The second step comprises a convex portion projecting from the surface of the conductive substrate by performing dry etching on the conductive substrate using the etching mask and the monitoring mask. After forming the three-dimensional structure, by performing wet etching on the side surface of the three-dimensional structure until the three-dimensional structure no longer supports the monitor mask, a cathode having a top surface having a diameter corresponding to the predetermined dimensional difference is provided. The method for manufacturing a field emission electron source according to claim 18, wherein the step is a step of forming a field emission electron source. 25. The second step comprises irradiating the monitor mask with light and monitoring the intensity of light reflected from the monitor mask, and when the intensity of the reflected light sharply decreases. 25. The method according to claim 18, further comprising a step of terminating the etching of the conductive substrate at a point.
Item 14. The method for producing a field emission electron source according to item 4. 26. The method according to claim 26, wherein the first step includes a step of forming three or more monitor mask rows of the plurality of monitor masks at predetermined intervals on the conductive substrate, and the second step Irradiates light to the three or more monitoring mask rows and monitors the intensity of diffracted light from the three or more monitoring mask rows, and the intensity of the diffracted light sharply decreases.
The method for manufacturing a field emission electron source according to any one of claims 18 to 24, wherein the etching of the conductive substrate is completed at the time of lowering.