JPH02111882A - Producing device of cubic boron nitride film - Google Patents

Abstract

PURPOSE:To obtain a cubic boron nitride film which is rigid and has high thermal conductivity and high electrical insulating properties by introducing a gaseous mixture of nitrogen and rare gas into a reaction chamber and generating electronic cyclotron resonant plasma and also impressing bias voltage on a base material while performing vapor deposition on the base material. CONSTITUTION:The inside of a reaction chamber 1 is preliminarily exhausted and a gaseous mixture of nitrogen or a compd. contg. nitrogen and rare gas is introduced into a plasma generating chamber 9 and the pressure of the inner part is maintained at the prescribed pressure. A magnetic field is impressed to the inside of the chamber 9 by a coil 10 for impressing the magnetic field and microwave is introduced via a waveguide 12. Electron cyclotron resonance plasma is generated and vapor deposition of boron is performed on a base material 3. High-frequency electric power is impressed on a base plate holder 4 from a high-frequency power source 8 to generate self-bias and a CBN film 16 is formed on the base material 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing cubic boron nitride, which is hard, has high thermal conductivity, and has excellent electrical insulation properties.

[Prior art] Boron nitride can be broadly classified into hexagonal boron nitride (hereinafter referred to as hBN), which is soft and has excellent lubricity and is easily synthesized at normal pressure.
and hard cubic boron nitride (hereinafter referred to as cBN), which is synthesized at high temperature and pressure.

Of these, cBN has the second highest hardness after diamond, as well as high thermal conductivity and high electrical insulation.
Attempts have been made to form a coating film on the surface of a base material.

Conventionally, methods for forming a boron nitride coating film on the surface of a substrate can be roughly divided into chemical vapor deposition (CVD;
physical vapor deposition (PVD) and physical vapor deposition (PVD).
VaporDeposition).

Here, for the former method, boron halide or
There is a method that is carried out in a reaction gas of a boride such as diborane and nitrogen or ammonia. On the other hand, the latter method is
There is an ion beam evaporation method. This method is described, for example, in the Journal of Vacuum Science and Technology, Volume A-1, Volume 2, Pages 323 to 325, 19
1983 (Journal of VacuumfflSc
ience and, Technology A-1
(2) (1983), the following procedure is performed using a Kauffman type ion source. First, after preliminary evacuation of the inside of the vacuum container to a predetermined reduced pressure state, borazine (83N3H6
) steam is introduced. Next, the electrons emitted from the tungsten filament collide with neutral particles of borazine and are ionized before reaching the anode. The borazine ions thus obtained are accelerated with an accelerator to create an ion beam, and a boron nitride film is obtained by this ion beam.

[Problem to be solved by the invention] Among the conventional methods for forming a coating layer made of boron nitride on the surface of a substrate, the CVD method is a simple thermal gas phase reaction, so it is difficult to form a soft hexagonal nitride layer. There is a problem in that only a coating layer made of boron is formed.

In addition, the method using ion beam evaporation has a problem in that the cBN content is low, so that the cBN has a much lower hardness than the original hardness of cBN.

The present invention was made in order to solve the above problems, and it is the production of a cubic boron nitride film that can extremely easily obtain a cubic boron nitride film that is hard, has high thermal conductivity, and has excellent electrical insulation properties. The purpose is to provide equipment.

[Means for Solving the Problems] Samurai The apparatus for producing a cubic boron nitride film obtained in the present invention includes a reaction chamber containing a substrate and a boron evaporation source, and a nitrogen or a nitrogen-containing compound and a diluted nitrogen in the reaction chamber. a mixed gas introducing means for introducing a mixed gas with a gas, an ECR plasma supply means for generating an electron cyclotron resonance plasma in the reaction chamber, and applying a bias voltage to the base material while depositing boron on the base material. It is characterized by comprising a bias voltage applying means.

[Effect] By using the device of the present invention, it is possible to enter the reaction chamber.

By creating electron cyclotron resonance plasma (ECR plasma) with high purity and high decomposition rate from raw material gas, and combining this with evaporation of boron, it is possible to deposit it on the substrate at high speed.
A cubic boron nitride film having excellent hardness, high thermal conductivity, and high electrical insulation properties can be obtained extremely easily and completely.

[Example] An embodiment of the invention is shown in FIG.

In FIG. 1, reference numeral 1 denotes a reaction chamber (vacuum container) having a gas introduction pipe 2. In FIG. A substrate holder 4 to which a substrate 3 is attached is installed in the upper part of the reaction chamber 1. The substrate holder 4 has a built-in heater 6 connected to a heater power source 5. Further, the base material holder 4 is connected to a high frequency power source 8 via a matching box 7.

In the figure, reference numeral 9 denotes a plasma generation chamber, and a magnetic field applying coil 10 is provided surrounding it. Also, this plasma generation chamber 9
A waveguide 12 is connected to the waveguide 12 via a vacuum sealing material 11 having good microwave transparency, such as a quartz plate. An evaporation source 13 is installed at the bottom of the substrate holder 4. For example, an electron beam evaporation source is used as the evaporation source, and metal boron 14 is used as the evaporation material. From here, boron vapor 15 is deposited onto the base material 3. Then, the cBN film 16 is formed on the base material 3 using the apparatus configured as described above. Therefore, first, the base material 3 made of a Si wafer is placed on the base material holder 4.
Attach to. Next, the inside of the reaction chamber (vacuum container) 1 is 2
After preliminary evacuation to a reduced pressure state below O=torr, nitrogen,
Argon gas mixture (35% nitrogen) is introduced at a flow rate of 20 d/min to maintain the internal pressure at 3 x 10-4 torr. Next, the base material 3 is heated with a heater 6 so that the temperature thereof becomes 400°C.

Next, the plasma generation chamber 9 is heated by the magnetic field applying coil 10.
A magnetic field is applied inside the chamber, and microwaves (2.45 GHz) are introduced into the plasma generation chamber 9 through the waveguide 12 to generate electron cyclotron resonance plasma (ECR plasma).

Boron is then evaporated from the evaporation source 13. Since the substrate holder 4 has a rotatable structure, uniform film formation can be performed. Further, high frequency power (13,56 MHz) is applied to the substrate holder 4 by a high frequency power source 8,
Generate self bias (-400V). In this way, the cBN film 16 with a thickness of 0.1 mm is formed on the base material 3.

As a result of examining the film obtained in the above manner by infrared absorption spectrum analysis, it was found that absorption at wave numbers near 1100 cm-', which is characteristic of cubic crystals, was observed, but absorption at wave numbers around 1350 cm-1 due to hexagonal crystals was observed.
No absorption near 780(2)-1 was observed.

In addition, from the electron beam diffraction device type using an electron beam diffraction device,
It was confirmed that the formed film was a polycrystalline film of cubic boron nitride.

Note that the mixing ratio of nitrogen and argon, which are reaction gases, is nitrogen 5.
When the content is 0% or more, the hBN phase is mixed in the coating.

And the self-bias voltage is -100V to -1000V
A cBN film is formed within the range of -100V and h
When the BN phase is mixed and the voltage exceeds -1000V, the etching effect becomes dominant and no film is deposited.

In the above embodiment, a case was described in which a mixed gas of nitrogen and argon was used, but a mixed gas of a compound containing nitrogen (for example, ammonia) and a rare gas, etc. may also be used.

In the present invention, examples of the nitrogen-containing compound include ammonia and the like. Further, examples of the rare gas include common gases such as argon, neon, xenon, and krypton. Furthermore, in the present invention, applying a bias to the base material is a process performed under reduced pressure and at a low temperature using the apparatus of the present invention, and by applying a bias voltage, ions generated in the plasma are caused to collide with the base material. This is to create conditions equivalent to high pressure and high temperature.

[Effects of the Invention] Since the present invention is configured as described above, the cubic boron nitride film manufacturing apparatus according to the present invention can produce cubic boron nitride film having excellent hardness, high thermal conductivity, and high electrical insulation. A boron film can be obtained very easily.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a cubic boron nitride film manufacturing apparatus according to an embodiment of the present invention. 1... Reaction chamber (vacuum container), 2... Gas inlet, 3
...Base material, 4...Base material holder 5...Heater power supply, 6...Heater 7...Matching box, 8...High frequency power supply, 9...Plasma generation chamber, 10
... Coil for applying magnetic field, 11 ... Vacuum sealing material, 1
2... Waveguide, 13... Evaporation source, 14... Metallic boron, 15... Hokigyoki, 16... cBN film, 1
7..Shield applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A reaction chamber containing a substrate and a boron evaporation source, a mixed gas introducing means for introducing a mixed gas of nitrogen or a compound containing nitrogen and a rare gas into the reaction chamber, into the reaction chamber. A cubic boron nitride film comprising: ECR plasma supply means for generating electron cyclotron resonance plasma; and bias voltage application means for applying a bias voltage to the base material while depositing boron on the base material. manufacturing equipment.