JPH0297488A - Formation of diamond pattern - Google Patents

Abstract

PURPOSE:To obtain the title high-purity diamond pattern of an optional shape by irradiating the specified region on the surface of a substrate with an ion, and then treating the part masked by ion irradiation by vapor growth. CONSTITUTION:A masking material 2 made of Cu is placed on a part on the surface of the silicon substrate 1, and the substrate 1 is irradiated by the N2 ion 3 (N<2+>) having accelerating energy of 100keV at about 2X10<16>units/cm<2>. The masking material 2 is then released, and diamond is deposited on the substrate 2 at about 1000Torr, the methane flow rate of about 1ml/min, the H2 flow rate of about 200ml/min, and the substrate temp. of about 800 deg.C for about 2hr by the filament CVD, etc. A diamond pattern of the continuous film 5 consisting of about 2mum-thick diamond is formed on the surface of the substrate 1 without forming diamond on the part irradiated by the ion 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method by which an arbitrary diamond pattern can be formed.

[Conventional technology]

Conventionally, patterning of a diamond thin film involves forming an amorphous carbon thin film by ion blasting or ion beam sputtering on a base material on which a photoresist pattern has been formed, and then depositing a diamond thin film on the surface of the amorphous carbon film. (Japanese Patent Application Laid-Open No. 62-241
No. 898). This diamond thin film is formed by the known hot filament CVD method using a carbon-containing compound, hydrogen or oxygen, water, etc. as raw materials, various plasma CVD methods, ion beam evaporation method, laser CVD method, method using combustion flame, etc. It is being said.

However, according to the prior art, it is necessary to first form an amorphous carbon film on a base material. Amorphous carbon is more easily etched than diamond by hydrogen, oxygen, water, etc., so in conventional diamond forming methods that use these etching gases together with carbon-containing compounds as raw materials, diamond precipitation on the amorphous carbon film is difficult. Have difficulty. Furthermore, even if a diamond thin film were to be formed on an amorphous carbon film, there would be problems with pattern accuracy, and it would also contain amorphous carbon as an impurity, which has mechanical, electrical, optical, and thermal properties that are inferior to diamond. , problems arise in the application of diamond thin films.

[Description of the first invention] The first invention (the invention described in the claims) has been made in view of the problems of the prior art described above, and is aimed at preventing the formation of diamonds in areas where diamond formation is unnecessary. The objective is to provide a method for forming patterns of arbitrary shapes made of pure diamond.

The first invention is a method for forming a diamond pattern on the surface of a base material, in which a portion of the surface of the base material where diamonds are not formed is irradiated with ions in advance, and then a portion of the surface of the base material that is not irradiated with ions is This is a diamond pattern forming method characterized by forming diamond by a vapor phase method.

According to the first invention, a pattern is formed by utilizing the fact that diamond formation is significantly suppressed when the surface of a base material is irradiated with ions. Therefore, there is no need to use amorphous carbon as in the past, and a pattern made of highly pure diamond can be formed with high precision.

The diamond pattern forming method of the first invention can be used to form patterns for heat sinks, electronic circuits, coating only necessary parts of high-hardness materials, and the like.

[Description of the Second Invention] Hereinafter, an invention that is a more specific version of the first invention (referred to as the second invention) will be described.

In the second invention, after modifying the surface of the base material by irradiating the surface of the base material with ions on the part where no diamond is formed, diamond is formed only on the non-ion irradiated part of the surface of the base material, Diamond formation is suppressed in the ion-irradiated area.

Suppression of diamond formation on the surface of the substrate material irradiated with ions can be achieved by irradiation damage such as amorphization or introduction of defects that occurs on the surface of the substrate material or the region near the surface due to ion irradiation, or recovery by recrystallization, etc. This is thought to be due to the reduction or disappearance of diamond nucleation sites.

In the second invention, the base material is Si.

Examples include various metals such as Mo, Ta, W, and Nb, or their carbides, nitrides, oxides, borides, and alloys, and one or more of these may be used in combination. Among them, Si, SiC, Si
3 N4,5iOz, Zro,, Sapphire, Mo,
W, Ta, Nb, and stainless steel are preferable. The base material may be used as it is in the second invention, but
Surface treatment with powder of diamond, alumina, etc. facilitates diamond nucleation during diamond formation.

The ion irradiation is performed using a known ion implanter, and the irradiation ions are arbitrary one or more monatomic ions or molecular/cluster ions among all ionizable elements and molecules.

From the viewpoint of ease of handling the ion source, ion current density, cost, etc., and productivity, we chose He", N", and N2".

Particularly effective are Ne", Ar"Xe", and Kr". The energy of the irradiated ions is set such that the average projected range of the ions ranges from 10 to 1 to effectively modify the surface of the base material.
It is set between IKeV and IMeV in accordance with a single ion so that the voltage is μm. The amount of ion irradiation is determined by the combination of the ion species and the substrate material, but usually 1X10" to 1X10" ions are irradiated per 1 ci of the substrate material, and in most cases, the substrate material 1c+fl produces sufficient surface modification. From 1X10'' to 1019 pieces per ion irradiation, it is appropriate to reduce the working time to 1X10. quality is possible and usually −
Controlled from 196°C to +500°C.

The portions to be irradiated with ions are only the portions where diamonds are not formed, and the portions where diamonds are to be formed are masked with a masking material during ion irradiation. This masking material can be made of any material as long as it has a thickness sufficient to measure the ion range, and may include a resist pattern made of photoresist by a known method, a pattern shield made of metal or plastic, or various vapor deposited films or A sputtered film may also be used. If a pattern is formed using a masking material made of carbon and hydrogen other than diamond, the masking material will be etched during diamond formation, and the work of removing the masking material can be omitted. Furthermore, a substrate in which ions are implanted in a pattern using a focused ion source without using a mask can also be used. Diamond is formed on the base material, which has been irradiated with ions in a partial region, by a known vapor phase method such as a thermal filament CVD method, various plasma CVD methods, an ion beam evaporation method, or a laser CVD method. Raw material gases include methane, ethane, propane, butane, pentane, hexane, ethylene,
Hydrocarbons such as acetylene and benzene, alcohols such as methanol, ethanol, propatool and butanol, ketones such as acetone, diethyl ketone and ethyl methyl ketone, and oxygen such as ethers such as methyl ether, ethyl ether and methyl ethyl ether. Diluting one or more mixed gases of nitrogen-containing hydrocarbons such as trimethylamine and triethylamine, and -carbon oxide with a mixed gas of hydrogen, oxygen, or both. and water vapor or a rare gas such as argon is added thereto. When converting diamond into a semiconductor, diborane,
This is possible by mixing a boron-containing compound such as boric acid, a phosphorus-containing compound such as phosphine, or an arsenic-containing compound such as arsine into the raw material gas. The pressure during diamond formation is controlled from 10-2 Torr to atmospheric pressure, but preferably 0.1 to 300 Torr. The temperature of the base material during diamond formation is 500-1200
°C is preferred. Further, the diamond to be formed may have any shape such as a film or a layer, and may have any thickness.

As a result of the above-mentioned diamond forming process, diamond is hardly deposited in the ion irradiated area, and diamond is formed only in the non-irradiated area, thereby forming a diamond pattern. Further, damage to the base material caused by ion irradiation is recovered by the heat treatment effect during diamond formation, and the properties of the base material are not impaired.

〔Example〕

The present invention will be explained in detail below.

Example 1 FIG. 1 shows a conceptual diagram for explaining the method of forming a diamond pattern according to this example.

A part of the (100) plane of the silicon base material 1 is masked by overlapping a copper plate masking material 2 ((A) in FIG. 1).
, nitrogen ions (Nz") 3 having an energy of 100 KeV are applied to the substrate material 1 at room temperature at a rate of 2X1 per d.
0" was irradiated ((B) in the same figure). After removing the copper plate ((C) in the same figure)
The pressure is 100Torr, the methane flow rate is 1mff1/
Diamond was deposited for 2 hours at a hydrogen flow rate of 1200 ml t/min and a substrate temperature of 800°C.

As a result, a continuous film 5 made of diamond with a thickness of 2 μm was formed in the non-ion irradiated area, but almost no diamond was found in the irradiated area, and the damage in the ion irradiation-damaged area 4 of the base material was also recovered (same as above). (D) in the figure).

Example 2 A diamond film pattern formation process was performed in the same manner as in Example 1, except that the energy of irradiated ions during ion irradiation was set to 60 KeV. As a result, a continuous film of diamond with a thickness of 2 μm was formed in the non-ion irradiated area, but almost no diamond was found in the irradiated area, and the irradiation damage to the base material was also recovered.

Example 3 The energy of irradiated ions during ion irradiation was set to 60 KeV,
Except that the irradiation dose was 2X10” per CIII,
A diamond film pattern formation process was performed in the same manner as in Example 1. As a result, a thickness of 2 μm was found in the non-ion irradiated area.
A continuous film of diamond was formed, whereas
Almost no guyarmond was found in the irradiated area, and the irradiation damage to the base material was also recovered.

Example 4 60Ke on a part of the base material made of silicon carbide sintered body
Nitrogen ion (N, °) with energy V is 1 at room temperature.
c++! After irradiating 2 x 10'6 pieces per diamond, diamond was deposited on the substrate by hot filament CVD at a pressure of 50 Tor'', a methane flow rate of 1 ml/min, a hydrogen flow rate of 200 ml/min, and a substrate temperature of 800''C for 2 hours.

As a result, a continuous film of diamond with a thickness of 2 μm was formed in the non-ion irradiated area, but almost no diamond was found in the irradiated area, similar to the silicon substrate, and the damage to the substrate material was also recovered.

Example 5 280 KeV applied to a part of a silicon substrate cooled with liquid nitrogen
After irradiating lXl016 argon ions (Ar") with an energy of Whereas a continuous diamond film was formed with a nucleation density of 1X10'' per 1 cl, the nucleation density in the ion irradiation area was extremely low at 5X10'' per 1 cTM (of course, it was impossible to form a thin diamond film). A scanning electron micrograph of the diamond thin film obtained in this example (
(magnification: 2700 times) is shown in FIG. In the figure, part (a) shows the diamond thin film formed in the non-ion irradiated area, and part (b) shows the base material of the ion irradiated part.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram for explaining the diamond pattern forming method according to Example 1, and FIG. 2 is a scanning electron micrograph showing the grain structure of the diamond thin film formed in Example 4. ■...Base material, 2...Masking material 3...Irradiation ions, 4...Ion irradiation damage area 5...Diamond thin film

Claims (1)

[Claims] A method of forming a diamond pattern on the surface of a base material, in which ions are irradiated on the surface of the base material where diamonds are not formed, and then diamond is applied to the areas on the surface of the base material that are not irradiated with ions using a vapor phase method. A method for forming a diamond pattern, characterized by forming a diamond pattern.