JP2001192858A - Method for depositing metallic thin film having microhole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deposit a metallic thin film having microholes with a diameter of 1 to 10 μm distributed at intervals of 1 to 10 μm on the surface of a solid without using a shielding mask, mechanical cutting and a lithographic device. SOLUTION: In this method for depositing a metallic thin film having microholes with a diameter of 1 to 10 μm distributed at intervals of 1 to 10 μm, the surface of a solid is deposited with a metallic thin film which is not chemically reacted with the solid surface, successively, the temperature of the metallic thin film is raised to the vicinity of the melting point of the metal, the metallic thin film is thermally flocculated, and a part of the solid surface is exposed. Moreover, it is also possible that, after the deposition of microholes, the synthesis of a solid film having constituting elements same as those of the above solid is executed, by which many solid projections are formed within the microhole regions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal having micro holes having a diameter of 1 to 10 .mu.m distributed at an interval of 1 to 10 .mu.m on a solid surface without using a shielding mask, mechanical cutting, or a lithography apparatus. The present invention relates to a method for forming a thin film.

[0002]

2. Description of the Related Art In general, when forming a hole in a metal thin film, a method is employed in which a shielding mask is placed near the solid surface when depositing the metal thin film, and the metal source is blown from above. However, in this method, it is difficult to form a micro hole having a diameter of several μm due to the mask design accuracy and the metal source wrapping around the back side of the mask.

In mechanical cutting, since there is no drill having a diameter of several μm, it is difficult to form micro holes having a diameter of several μm. Instead, electrical discharge machining or laser beam machining is used. However, in these methods, since it is necessary to open micro holes one by one, a repeated processing process is required to form a large number of micro holes. Further, since the processed portion is locally heated at the same time as being cut, there is an essential problem that the solid surface under the metal thin film is also etched or deteriorated.

When microholes are formed by lithography, after depositing a metal thin film, first, a resist is applied on the metal thin film, then exposure is performed using a lithography apparatus, and finally, the resist is etched.
This is done in a staged process. In this process, it is necessary to prepare an expensive apparatus called a lithography apparatus.

[0005] When microholes are formed by a focused ion beam, it is necessary to open the microholes one by one. Therefore, in order to form a large number of microholes, a repetitive processing process is required. In addition, there is an essential problem that the solid surface under the metal thin film is etched or deteriorated at the same time as the processed portion is cut. further,
It is necessary to prepare an expensive device called a focused ion beam device.

[0006]

According to the present invention, there is provided a method for forming a metal thin film having microholes on a solid surface, comprising depositing a metal thin film which does not cause a chemical reaction with the solid surface on the surface of the solid. The metal thin film is heated to a temperature close to the melting point of the metal to thermally aggregate the metal thin film, thereby exposing a part of the solid surface, whereby 1 to 10
It is characterized in that microholes having a diameter of 1 to 10 μm distributed at μm intervals are formed.

When a solid having a metal thin film deposited on its surface is heated to a temperature near the melting point of the metal, the metal thin film thermally aggregates,
As a result, a large number of holes are formed by exposing a part of the solid surface covered with the metal thin film. The size of the exposed hole area depends on the element type of the metal, the constituent element type of the solid,
It largely depends on the type of the termination element on the solid surface, the heating temperature, and the heating atmosphere.

The reason why the temperature of the metal thin film is raised near the melting point of the metal is to prevent the melting of the entire metal thin film and to impair the morphology of the thin film. It is the temperature at which the metal melts but the shape of the entire metal can be maintained. As a method of forming a metal thin film, resistance heating, electron beam evaporation, sputtering, CVD
And an electroplating method. The preferred thickness of the metal thin film is a thickness that does not cause peeling from the solid surface and (hole diameter)> (metal film thickness).
When forming a hole having a diameter of μm, the thickness of the metal thin film is about 1 μm or less. Examples of the solid surface include, for example, a diamond surface, and a metal that does not cause a chemical reaction with these solid surfaces can be, for example, gold.

Further, the present invention relates to a method for forming an electron-emitting device using the above-mentioned microholes, wherein the solid is diamond, ZnSe, GaN, BN, CN, BCN, AlN or any other substance having a band gap of 4 eV or more. After forming a metal thin film having microholes on the surface of the substrate by the method according to claim 1, depositing a single crystal or polycrystal having the same constituent elements as the substrate on the surface of the substrate. Electron, characterized by forming a large number of single-crystal or polycrystalline projections having the same constituent elements as the substrate on the surface of the single-crystal or polycrystalline substrate by etching the metal thin film having microholes. This is a method for forming an emission element.

[0010] In the above method, depositing a single crystal or polycrystal having the same constituent elements as the substrate on the surface of the substrate means, for example, for a diamond substrate, a diamond single crystal, a diamond polycrystal, or a diamond-like crystal. carbon,
This refers to depositing a carbon nanotube layer or a graphite layer. By forming microholes in a metal, selective growth on a solid surface can be performed. For example, when a microhole is formed on a diamond substrate and then a diamond thin film is synthesized, growth occurs only in a region where the diamond substrate is exposed. When the metal is etched with a chemical after growth, a diamond substrate having a large number of diamond protrusions is formed. The diamond having the projection can be applied to an electron-emitting device.

Further, a metal film having microholes is formed on a diamond single crystal substrate, and subsequently, a diamond thin film is grown under a growth condition in which lateral growth, ie, growth of diamond in a direction perpendicular to the diamond surface, is mainly performed. Is deposited, a diamond single crystal having a buried metal thin film can be formed.

[0012]

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a method for forming a metal thin film having microholes on a solid surface by depositing a metal thin film on a solid surface and then heating the solid. Is provided. FIG. 1 is a schematic diagram showing a process of forming a metal thin film having micro holes on a solid surface. (a) before the deposition of the metal thin film,
(b) shows the state after the deposition of the metal thin film, and (c) shows the state after the heat treatment. In the process of forming microholes, first, a metal thin film 2 is deposited on the surface of the solid 1 (FIG. 1a) (FIG. 1).
b). Next, by performing heat treatment, the metal thin film 2 thermally aggregates, so that the surface of the solid 1 is exposed in a part of the region,
Micro holes 3 are formed (FIG. 1c).

There are no particular restrictions on the metal element species, solid constituent element species, solid surface termination element species, heating temperature, and heating atmosphere used in the microhole formation technology. For the metal, gold, which is a metal with low reactivity, is used for the solid.For the solid, the single crystal with the lowest reactivity, which is a crystal having a diamond structure with good structural contrast, is used as the terminal element species on the surface of the solid. Since only one bond is provided, hydrogen whose bonding state is ideal is heated at a heating temperature slightly lower than the melting point of gold.
The most typical example of the heating atmosphere at 0 ° C. is to use the same hydrogen as the terminating atom in order to suppress the desorption of the terminating atom.

Example 1 On a high-pressure synthesized {100} diamond substrate, gold having a film thickness of 100 nm was deposited by an electron beam evaporation apparatus, and then kept at 900 ° C. in a hydrogen atmosphere to thereby obtain an interval of 2 to 10 μm. 2-5 distributed diameter
A gold thin film having μm microholes was formed.
As shown in the optical micrograph of FIG.
Microholes (black spots) having a diameter of 2 to 5 μm at μm intervals were formed.

COMPARATIVE EXAMPLE 1 Titanium having a thickness of 100 nm was deposited on a high-pressure synthetic {100} diamond substrate by an electron beam evaporation apparatus and subsequently kept at 900 ° C. in a hydrogen atmosphere. Caused a chemical reaction, and no microhole was formed.

[0016]

As described above in detail, according to the present invention, a metal thin film formed on a solid surface has a diameter of 1 to 10 μm distributed at an interval of 1 to 10 μm without using a dedicated lithography apparatus. Micro holes can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a process of forming a metal layer having micro holes on a solid surface.

FIG. 2 is an optical microscope photograph as a drawing of the surface of the metal thin film obtained in Example 1.

Continued on the front page F term (reference) 4K029 AA04 BA05 BA34 BB02 BB03 BB08 BB09 BD00 GA00 GA01 4K030 BA01 BA28 BB02 BB03 BB13 CA01 DA08 DA09 LA11 4K044 AA06 AA11 AA13 BA08 BA18 BB08 BC14 CA13 CA14 CA18 CA67

Claims (2)

[Claims] 1. Depositing a metal thin film that does not cause a chemical reaction with the solid surface on the surface of the solid, and subsequently heating the metal thin film to near the melting point of the metal to thermally aggregate the metal thin film. Characterized in that a part of the solid surface is exposed by the method, wherein diameters distributed at an interval of 1 to 10 μm are 1 to 10 μm.
A method for forming a metal thin film having m microholes. 2. The solid is diamond, ZnSe, GaN, BN, C
A monocrystalline or polycrystalline substrate of N, BCN, AlN, or another substance having a band gap of 4 eV or more, and after forming a metal thin film having microholes on the surface of the substrate by the method according to claim 1, the substrate By depositing a single crystal or polycrystal having the same constituent elements as the substrate, and then etching the metal thin film having micro holes, a single crystal or polycrystal having the same constituent elements as the substrate is formed on the surface of the single crystal or polycrystal substrate. A method for forming an electron-emitting device, comprising forming a large number of projections of a crystal.