JP2633968B2 - Diamond coating material and its manufacturing method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for forming diamond on a substrate.

[Prior Art] In recent years, a technique for forming a diamond thin film by vapor phase synthesis has been developed.

Conventionally, there has been known a method of forming fine scratches on a substrate surface using abrasive grains (diamond, silicon carbide, cubic silicon nitride, etc.) to obtain a film-like diamond, thereby increasing a nucleation density.

Furthermore, it is known to form various substances on the surface of a substrate in order to control nucleation and crystal growth. For example, Japanese Patent Application Laid-Open No. 64-5995 discloses that a high film forming rate can be obtained by performing plasma vapor deposition in the presence of a transition metal.

Further, in JP-A-64-9892, Cr, Fe, Co, and Ni are dispersed and adhered, and in JP-A-64-24092, Pd, Pt, Au, and Y are dispersed and adhered to provide a large particle size. A method for obtaining diamond particles is disclosed. Furthermore, Japanese Patent Application Laid-Open No. Sho 64-17870 discloses a method of obtaining a diamond film having good smoothness by introducing a gas containing Ni, Mn, and Ge into a plasma generation region during or before film formation. Have been. In Japanese Patent Publication No. 63-53159, 100
A method for obtaining fibrous diamond by adhering Fe, Co, and Ni powders of 0% or less is disclosed.

[Problems to be Solved by the Invention] However, the conventional method of increasing the nucleation density by a fine scratching process using abrasive grains involves a method in which an abrasive or polishing debris remains on a substrate or a diamond nucleus is formed along a scratch. In some cases, unevenness was apt to occur in diamond deposition because of the occurrence of diamond. Further, there is a drawback that the nucleation density varies greatly depending on the polishing tool, the type of abrasive grains, and the particle size, and diamond cannot be formed uniformly with good reproducibility. Also, residual abrasives and polishing debris become a major obstacle when used in, for example, a semiconductor manufacturing process that requires a very clean condition.

Further, in the conventional example in which various substances are formed on the surface of the base to control nucleation and crystal growth, there is no clear description of the abundance of the forming substance and its range for forming a diamond film with good flatness. However, a diamond film cannot always be formed with good flatness.
For example, it is generally said that diamond formation on Fe, Co, Ni substrates is very difficult. JP-A-63-303891 discloses a pattern forming method using the property that diamond is not formed on Fe, Co, and Ni. As described above, depending on the amount and distribution of the forming substance, diamond may not be formed, diamond particles having a large particle size may be formed, fibrous diamond may be formed, or film diamond may be formed. It was revealed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and provides a diamond coating material capable of forming a film-like diamond having no deposition unevenness and good flatness, and a method for producing the same. The purpose is to:

[Means for Solving the Problems] The diamond coating material of the present invention is a film-like material containing at least one metal selected from the group consisting of iron, cobalt, nickel and chromium having a thickness of 0.2 nm or more and 10 nm or less. Obtained by a substrate provided with a body or a particulate body and a gas phase synthesis,
It has a diamond film with an average surface roughness RSM of 12 nm or less.

In addition, the method for producing a diamond coating material of the present invention includes, on the surface, a metal layer containing at least one element selected from iron, cobalt, nickel, and chromium as a main component in an amount of 0.2 nm or more and 10 n or more.
a step of forming diamond by a vapor phase synthesis method on a substrate having a thickness of not more than m.

Further, the method for producing a diamond-coated material of the present invention further comprises, on the surface, a metal layer containing at least one selected from iron, cobalt, nickel and chromium as a main component in an amount of 0.2 nm or more and 10 nm or more.
a step of forming diamond by a vapor phase synthesis method on a substrate having a thickness of not more than m.

Examples of the metal containing at least one selected from iron, cobalt, nickel and chromium as a main component include stainless steel having a composition such as SUSU316 (Fe-18Cr-8Ni). Of course, other compositions may be used. In the following, a simple substance of iron, cobalt, nickel or chromium or an alloy thereof and a metal mainly containing at least one selected from iron, cobalt, nickel or chromium will be referred to as Fe, Co, Ni, Cr. Or an alloy thereof.

[Operation] The following operation of the present invention will be described together with the knowledge obtained when the present invention is carried out.

The present inventor has made a fundamental review of the substrate conditions, film forming conditions, and the like in order to clarify the reason why a diamond film having good flatness cannot be formed in the above-described conventional technology. In the process, it was found that the type and thickness of the forming substance formed on the surface of the substrate before diamond formation may be related to the flatness of diamond.
However, it is completely unclear which process is used to obtain the flatness, and it is also completely unknown whether the thickness differs depending on the type of the material to be formed.

Therefore, the present inventors should elucidate such unknown points,
As a result of detailed experiments, it was clarified that the type and thickness of the forming substance were not independent, and that flatness was obtained only when there was a delicate combination of a specific type and a specific thickness. Invented the invention.

That is, by forming a simple substance of Fe, Co, Ni, Cr or an alloy thereof on the substrate in a limited range of 0.2 nm to 10 nm, the nucleation density of diamond is greatly increased,
It has been found that a diamond with good flatness can be formed.

That is, the film thickness in the range of 0.2 nm to 10 nm has a critical significance, and it has been found that the desired object can be achieved only within this range, and the present invention has been accomplished.

The details of this cause are unknown, but if the thickness of the unit of Fe, Co, Ni, Cr or its alloy is in the range of 0.2 nm to 10 nm, (1) the above metal or alloy with a large amount of solid solution of carbon Is formed, and this becomes a nucleation origin of crystal nucleation,
Diamond nucleation density increases.

(2) Fe, Co, Ni, Cr alone or an alloy thereof acts as a catalyst for decomposing a gas such as hydrocarbons that form diamond, increasing the degree of supersaturation of carbon and increasing nucleation.

It is considered that film diamond with good flatness can be easily formed for the reasons described above.

The thickness of Fe, Co, Ni, Cr alone or its alloy is 0.2 nm
To 10 nm. Desirably, it is 2 nm to 8 nm. 0.2nm
If it is less than 10 nm, the effect of increasing the nucleation density is small. Probability is small.

The metal or alloy may be formed in either a uniform film (film form) or a dispersion (particle form). However, the dispersion or formation tends to cause unevenness in the thickness of the deposited diamond film. When forming a uniform diamond film, it is desirable to form the metal or alloy into a uniform film.

As a method of forming the above metal or alloy on the substrate,
For example, a high-frequency sputtering method, a direct-current sputtering method, an electron gun vapor deposition method, and the like can be given, but any method can be used as long as it can be formed within the above-mentioned thickness range.

Furthermore, by coating a part of the basic surface with the above metal or alloy to a thickness within the above range, it is also possible to selectively form diamond only on the coated part (see FIG. 2). As a method of forming the above metal and alloy on only a part of the substrate surface, when coating the metal and alloy, a mask is applied to the substrate surface to cover only necessary portions,
For example, it is possible to cover only a necessary portion of the surface by a usual lithography technique.

As a method for forming diamond, any of conventionally known methods such as a hot filament CVD (chemical vapor deposition) method, a microwave plasma CVD method, a high frequency plasma CVD method, and a direct current plasma CVD method may be used. For example, FIG. 3 shows a hot filament CV which is an embodiment of a diamond forming method.
D device is shown. In the figure, 4 is a quartz tube, 5 is a heater, 6
Is a tungsten filament, 7 is Fe, Co, Ni, C on the surface
a substrate coated with r alone or an alloy thereof, 8 is a gas inlet connected to a gas cylinder and a gas flow meter (not shown), and 9 is a gas exhaust connected to an exhaust device and a pressure adjusting valve (not shown). Mouth.

In addition, the material of the base on which the simple substance of Fe, Co, Ni, and Cr or the alloy thereof is formed is not particularly limited, and for example, Si, W, SiC, or the like can be used.

[Example] Hereinafter, an example will be described in more detail.

(Example 1) A Fe film was applied to a silicon single crystal substrate (1 inch φ, thickness 0.5 mm, plane orientation (100)) by high frequency sputtering (using a Fe target, applying 13.56 MHz high frequency, output 200 W, gas flow rate A).
r: 200 SCCM, pressure 1 × 10 ⁻³ Torr) to form a 5 nm thick film (FIG. 1).

Next, this substrate was set in a hot filament CVD apparatus shown in FIG. 3 to form diamond. First, the inside of the quartz reaction tube was evacuated to 10 ⁻³ Torr using an exhaust device (not shown). Next, hydrogen and methane gas were introduced at 220 ml / min and 1 ml / min, respectively, using a gas cylinder and a gas flow meter (not shown), and the pressure in the quartz tube was adjusted with a pressure adjustment valve (not shown).
80 Torr. Next, after heating the substrate to 850 ° C. by the heater 5, the tungsten filament 6 was heated to about 2100 ° C. using a power supply (not shown). Methane and hydrogen gas are decomposed by the heated filament to form diamond on the substrate.

After the film was formed for 6 hours, it was confirmed by SEM (scanning electron microscope) that a diamond film having a thickness of about 5 μm was uniformly and uniformly formed (average surface roughness RMS: 12 nm) on the substrate. (FIG. 1).

[Other Examples] (Examples 2 to 10, Comparative Examples 1 to 3) Diamond formation was performed in the same manner as in Example 1 except that the type and thickness of the coating material were changed as shown in Table 1.
A diamond was formed as shown in Table 1.

That is, in Examples 2 to 10, the thickness of the coating material was all in the range of 0.2 to 10 nm, and in all cases, the film-like diamond was formed uniformly and almost without deposition unevenness. In particular, in Examples 2 to 8 in which the thickness of the coating material was 2 nm to 8 nm, there was no unevenness in deposition.

On the other hand, in Comparative Examples 1 to 3, the thickness of the coating material was out of the range of the present invention, and no film-like diamond was formed.

Example 11 An Fe film was formed on a silicon substrate similar to that of Example 1 by lithography using a 5 μm line and space (5 μm
A substrate having a thickness of 3 nm (FIG. 2) was formed under the same conditions as in Example 1 with a width of 5 μm and a diamond film of 5 μm was selectively formed only on the Fe film coating. The formation was confirmed by SEM observation (FIG. 2).

[Effects of the Invention] According to the present invention, it is possible to form a film-like diamond having no unevenness of deposition and good flatness.

[Brief description of the drawings]

FIG. 1 is a schematic view of the formation of diamond according to the present invention. FIG. 2 is a schematic view of the selective diamond formation of the present invention. FIG. 3 is a conceptual diagram showing an example of a diamond forming apparatus used in the present invention. DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... single or alloy film (coating material) of Fe, Co, Ni, Cr, 3 ... diamond film, 4 ... quartz reaction tube, 5 ... heater, 6 ... tungsten filament, 7: substrate, 8: gas inlet, 9: gas outlet.

Claims (6)

(57) [Claims] A substrate provided with a film or particle containing at least one metal selected from the group consisting of iron, cobalt, nickel and chromium having a thickness of 0.2 nm or more and 10 nm or less, and a gas phase Average surface roughness RSM12n obtained by synthesis
A diamond coating material having a diamond film of m or less. 2. The method according to claim 1, wherein the thickness of the film or the particle is 2 nm to 8 nm.
The diamond coating material according to claim 1, wherein the diamond coating material is set in the range of: 3. The method according to claim 1, further comprising the step of forming diamond by a vapor phase synthesis method on a substrate having a surface formed of a simple substance of iron, cobalt, nickel or chromium or an alloy thereof having a thickness of 0.2 nm or more and 10 nm or less. Manufacturing method of diamond coating material. 4. The method according to claim 3, wherein said thickness is 2 nm to 8 nm. 5. A method in which diamond is formed by a vapor phase synthesis method on a substrate having a metal layer mainly composed of at least one selected from iron, cobalt, nickel and chromium having a thickness of 0.2 nm or more and 10 nm or less. A method for producing a diamond-coated material, comprising: 6. The method according to claim 5, wherein said thickness is 2 nm to 8 nm.