JPH0784644B2 - Method and apparatus for forming cubic boron nitride - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses cubic boron nitride, which is used as an abrasive grain or a cutting tool material, for wear-resistant parts.
Or a method of forming a cubic boron nitride formed by vapor-phase synthesis method on the cutting tool, to an apparatus及benefactor.

[0002]

2. Description of the Related Art Cubic boron nitride (hereinafter referred to as cBN)
Has a hardness second to that of diamond and has a higher thermal stability in air than diamond, and is therefore widely used as a material for abrasive grains or cutting tools, and is a very useful material in industry. Conventionally, cubic boron nitride has been artificially synthesized at high temperature and high pressure, but in recent years it has been found that it can be synthesized even in the gas phase. As an example thereof, an ion plating method in which boron is melted and evaporated by an electron beam as disclosed in Japanese Examined Patent Publication No. 3-1377, Mineda, Yasunaga: Journal of Precision Engineering, Vol.53.
(1987) 1532, a method using a combination of evaporation of hexagonal boron nitride (hereinafter referred to as hBN) by a laser beam and nitrogen ion irradiation, Y. Ichinose et al .: Proc. 11
th Symp. on ISIAT'87 Tokyo (1987) 469, using diborane as a boron raw material and ammonia as a nitrogen raw material, using inductively coupled high frequency discharge and a hot filament together, A. Chayahara et al .: ISPC-8 Tokyo (19
As shown in 87) 2440, there is a method in which diborane and nitrogen gas are used as raw materials and activated by high frequency and magnetic field or high frequency, microwave and magnetic field.

[0003]

Among the above-mentioned methods, except for the method and, all of the methods use a boron-containing gas such as B ₂ H ₆ as a part of the raw material. Boron-containing gas is widely used in the field of semiconductors and the like, and it is a simple raw material for boron, but it is also a gas with extremely high toxicity. Therefore, when using these gases, facilities equipped with safety equipment and There are drawbacks such as the need for equipment for detoxifying exhaust gas.

[0004] Such a harmful gas is always in danger of accidents even if facilities and equipment are thoroughly prepared. Therefore, it is industrially very useful if cBN can be stably synthesized without using a harmful gas. As described above, there is a conventional method that does not use a boron-containing gas, but the above method is a physical vapor deposition method in which a hollow cathode or an electron gun is used to melt and evaporate boron in a crucible with an electron beam. According to this, since it is difficult to control the evaporation amount of boron and the B / N ratio is difficult to control, it is difficult to stably synthesize cBN. Also, the above method is h
Although BN is vaporized by a laser beam to form cBN on the substrate, it has been attempted as a method not using a boron-containing gas as a raw material, but there is a problem that it is difficult to obtain a cBN single-phase film.

[0005]

Therefore, in the present invention, solid boron is used as a boron source or hBN is used as a boron and nitrogen source, and cB is more stable than conventional methods.
The method of forming N was studied. As a result, by sputtering a boron or cBN plate at a high frequency, these constituent elements can be stably supplied into the gas phase, and this gas is further subjected to the action of a high frequency electric field and a thermoelectron at a high temperature from a filament heated by red heat. To accelerate gas decomposition
It was found that by doing so, cBN can be stably formed.

That is, using the apparatus according to the present invention shown in FIG. 1, one of the pair of parallel plate type electrodes (first plate type electrode) 2 facing each other in the vacuum chamber 1 is boron or boron. By mounting a target 4 of hBN and applying a high frequency to the electrode using a high frequency power source 5, boron or boron and nitrogen, which are target constituent elements, are supplied into the gas phase by sputtering, and these elements are supplied. The mixed gas containing the same is placed between a pair of parallel plate type electrodes and activated by the action of a high frequency electric field introduced into the vacuum chamber through the filament 6 heated by energization and the first electrode 2, and the other electrode The cBN is efficiently synthesized on the heated base 7 placed on the (second flat plate type electrode) 3.

At this time, as the atmosphere gas in the vacuum chamber 1, a mixed gas in which nitrogen or ammonia is supplied to a mixed gas of argon and hydrogen is used. The argon gas mainly has an effect of efficiently sputtering the target material, and hydrogen reacts with the sputtered boron gas to form a hydrogen compound of boron and hB which is simultaneously deposited with cBN.
It has a function of selectively etching N. Further, nitrogen atoms in nitrogen gas or ammonia gas serve as a raw material for forming cBN.
In the case of using, since nitrogen atoms are still supplied, the partial pressure of nitrogen gas or ammonia gas in the supply gas may be low.

The composition of the supply gas can be adjusted in a relatively wide range, but if the amount of argon gas is too small, the sputtering rate becomes slow, and if it is too large, the amount of boron in the gas phase increases and cBN is difficult to form. Therefore, the partial pressure of the argon gas with respect to the total gas pressure is preferably 10% or more and 90% or less. Further, when the (nitrogen partial pressure) / (nitrogen partial pressure + hydrogen partial pressure) ratio is 50% or more, a large amount of hBN component appears in the synthesized film, and when it is 2% or less, the boron component is large in the film. It is preferably 2% or more and 50% or less. (Ammonia partial pressure)
/ (Ammonia partial pressure and hydrogen partial pressure) ratio also about the reasons of 4% or more, preferably 70% or less.

The filament 6 emits thermoelectrons at high temperature,
It has the effect of promoting the decomposition of gas in the gas phase in cooperation with the high frequency, and it is preferable that the temperature is high, but if the temperature is too high, the life of the filament will be shortened. Is practically 1600 ℃ ~ 25
The range of 00 ° C is preferred. The heating of the substrate 7 is performed by using the heating device 8 provided in the second flat plate type electrode 3 on the side where the substrate is mounted. When the substrate temperature is below 300 ° C, a large amount of hBN remains in the film, and above 1000 ° C, the cause is unknown.
Since the formation rate of the N film becomes slow, it is preferably 300 ° C or higher and 1000 ° C or lower.

When the pressure in the vacuum chamber 1 becomes low, the synthesis rate of cBN becomes slow, and when it is too high, it becomes difficult to activate the gas by high frequency. Therefore, the pressure in the vacuum chamber is preferably 0.1 Pa to 1500 Pa. .

The high frequency applied to the first flat plate type electrode 2 gives a high frequency electric field in the vacuum chamber, and when the high frequency output is increased, the material of the electrode 3 is also sputtered.
Therefore, the electrode material, which is an impurity, increases in the atmospheric gas with the output of the high frequency. This effect is the second
The protective plate 9 made of boron or hBN is mounted on at least the surface side of the flat plate electrode 3 facing the first flat plate electrode 2, and the elements sputtered from the second flat plate electrode 3 side are used for cBN synthesis. It can be prevented by using only necessary elements.

[0012]

According to the method of the present invention, one of the pair of parallel-arranged flat plate electrodes (first flat plate electrode) 2 is used.
It is possible to supply boron, which is a target constituent element, or boron and nitrogen to the atmosphere continuously by mounting a target made of boron or hBN on the substrate and applying a high frequency to the electrode. the mixed gas containing the element, facing the other electrode (second plate electrodes) 3
Placed between and facing the target and substrate and on the substrate
By energizing the filaments arranged in close proximity,
Heating it to a higher temperature, causing the filaments to emit thermoelectrons
It is activated by both the action of promoting the gas decomposition and the action of the high frequency electric field introduced into the vacuum chamber 1 and is harmful to the outside on the substrate placed on the other second flat plate type electrode 3. It is possible to continuously synthesize cBN without supplying the element-containing gas.

[0013]

EXAMPLE An example of an apparatus for forming cubic boron nitride used in the present invention will be described with reference to FIG. Above the vacuum chamber 1, a flat first flat plate electrode 2 having a target 4 made of boron or hBN mounted on its front end face is located and connected to a high frequency power source 5. Further, a second flat plate type electrode 3 is provided so as to face the first flat plate type electrode 2, and the base 7 is placed on the facing surface side of the target 4. A heating device 8 connected to a heating power supply 15 is built in the second flat plate electrode 3 and heats the substrate 7. Between both electrodes
Placed facing the target and substrate and in close proximity to the substrate
A filament 6 is provided which is arranged and connected to an AC power supply 10 for emitting thermoelectrons at high temperature and promoting the decomposition of gas in the gas phase in cooperation with high frequency. The embodiment shown in FIG. 2 has substantially the same structure as that shown in FIG.
The second flat plate electrode 3 is made of boron or hBN on the surface side of the second flat plate electrode 2 facing the target 4, and cBN is necessary for synthesizing the element sputtered from the second electrode 3. A protection plate 9 for only elements is attached,
The substrate 7 is placed on the protective plate, and the exhaust port 1
1 is different in that an exhaust valve 13 is provided and a gas supply valve 14 is provided at the gas inlet 12.

An example of the method for forming cubic boron nitride according to the present invention will be described below. (1). A boron sintered plate was used as a target material, a cemented carbide cutting tip (JIS: SNGN120308) was used as a base material for cBN synthesis, and the present invention was carried out using the apparatus shown in FIG. First, the inside of the vacuum chamber 1 is exhausted to 1 × 10 ⁻³ Pa by a vacuum exhaust device (not shown) connected to the exhaust port 11, and then the gas inlet port 12 connected to a gas supply device (not shown).
A mixed gas consisting of 50% argon, 35% hydrogen, and 15% ammonia was supplied at a total flow rate of 100 SCCM, and the pressure in the vacuum chamber was set to 100 Pa while adjusting the exhaust rate.
Next, the heating device 8 installed in the second flat plate type electrode 3
The heating power source 15 is energized to heat the substrate 7 to 500
While keeping the temperature at ℃, the tungsten-made tungsten filament 6 placed 10 mm above the substrate 7 is used as an AC power source 1.
After heating to about 2000 ° C. by energization using 0, a high frequency power of 500 W was applied to the first flat plate type electrode 2 by using the high frequency power supply 5. When a synthesizing process was performed for 4 hours, a cBN film having a thickness of 1.5 μm was synthesized on the upper surface of the substrate. As a comparative example, when a synthesis treatment was performed under the same conditions as in the above-described example of the present invention except that the filament was not heated by energization, a film containing hBN as a main component was synthesized on the substrate, and cBN was not synthesized. It was

(2). HBN as target 4 material
Using a sintered plate, a 12 mm x 12 mm x 5 mm silicon nitride plate as a base for synthesizing cBN, the cubic boron nitride according to the present invention was formed using the apparatus shown in FIG. First, the second flat plate type electrode 3
In order to prevent the electrode material from being sputtered, a protective plate 9 made of a hBN sintered body was attached to the surface of the. Then, the inside of the vacuum chamber 1 is connected to the exhaust port 11 via the exhaust valve 13 by a vacuum exhaust device (not shown) at 1 × 10 ⁻³ Pa.
After exhausting up to, the exhaust valve is closed, and a mixed gas having a volume ratio of 60% argon, 36% hydrogen, and 4% nitrogen from a gas inlet 12 connected to a gas supply device (not shown) via a gas supply valve 14. Was filled, and when the pressure in the vacuum chamber reached 150 Pa, the gas supply valve 14 was closed and the gas supply was stopped. Next, the heating device 8 installed in the second flat plate electrode 3 is electrically heated to keep the temperature of the base 7 at 700 ° C., and the tungsten filament 6 placed 10 mm above the base 7 is used as an AC power source. 10 is heated to about 2000 ° C by energization, and then a high frequency power source 5 is used to form an electrode 2
A high frequency of 700 W was applied. As a result of performing the synthesizing process for 4 hours, the upper surface of the substrate 7 was cBN with a thickness of 2 μm.
The membrane was synthesized. Thus, cBN could be continuously synthesized in a closed system without supplying a boron-containing gas from the outside. Further, the consumption amount of the synthesis atmosphere gas is only the initial filling amount, which is economical.

[0016]

According to the method of the present invention, since the element for cBN synthesis is supplied from the boron or hBN target 4 into the cBN synthesis atmosphere by sputtering, it is possible to use a source gas containing no poisonous boron gas. CBN can be continuously synthesized in the phase, and when hBN is used as the target material, cBN can be synthesized without continuously supplying the raw material gas into the vacuum chamber. It is economical and very industrially beneficial.

Further, the apparatus according to the present invention is connected to a high frequency power source in a vacuum chamber and has boron or hB on the front surface.
A first flat plate type electrode provided with a target made of N and a second flat plate type electrode having a substrate mounted thereon and a heating device for heating the base body are arranged to face each other, and further connected to an AC or DC power source. Since the formed filaments are arranged between both electrodes, cBN could be supplied to the substrate without using the toxic boron-containing raw material gas as described above.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of the cBN synthesizer of the present invention.

FIG. 2 is a schematic view of another embodiment of the cBN synthesizer of the present invention.

[Explanation of symbols]

 1 Vacuum Tank 2 First Flat Plate Electrode 3 Second Flat Plate Electrode 4 Target 5 High Frequency Power Supply 6 Filament 7 Base 8 Heating Device 9 Protective Plate 10 Filament Heating Power Supply 11 Exhaust Port 12 Gas Supply Port 13 Exhaust Valve 14 Gas Introduction Valve 15 Power supply for heating device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ryoichi Watanabe 20 Ishigane Co., Ltd., Toyama City, Toyama Prefecture (72) Kenichiro Yamagishi 20 Ishigane Co., Ltd., Toyama City, Toyama Prefecture (56) References (56) References JP-A-3-107450 (JP, A)

Claims (6)

[Claims] 1. A first flat plate-type electrode, on which a target containing boron or hexagonal boron nitride as a main component is mounted on the opposite surface, and which is connected to a high frequency power source, and a heating means, and a surface of the target is provided. Then, the second flat plate-type electrode on which the substrate is placed is placed in the vacuum device so as to face it , and is energized and heated.
By doing so, thermoelectrons are emitted at high temperature to accelerate gas decomposition.
Insert the filaments soaked between the electrodes ,
Lamentr faces the target and the substrate and
An apparatus for forming cubic boron nitride, characterized in that it is arranged close to a substrate . 2. The at least first of the second flat electrodes
The part of the flat electrode facing the target is covered with a boron plate or a hexagonal boron nitride plate , and the boron plate or the hexagonal nitride plate is covered.
Cubic boron nitride of the forming apparatus according to claim 1 wherein placing the substrate on a boric material plate. 3. After evacuating the inside of the vacuum chamber , argon and hydrogen are mixed into the vacuum chamber, and a gas in which nitrogen is mixed is continuously supplied to the vacuum chamber, and the partial pressure ratio of the argon gas to the total gas pressure is 10. % To 90 %, the ratio of the nitrogen partial pressure to the sum of the nitrogen partial pressure and the hydrogen partial pressure is 2% to 50%, and after the pressure in the vacuum chamber reaches 0.1 Pa to 1500 Pa, the facing arrangement is performed. With boron or hexagonal boron nitride as the main component
First flat plate type electrode equipped with a target for heating and heating means
The target and the substrate interposed between a second flat plate type electrode having a substrate facing the target and having a substrate mounted thereon.
At a high temperature, an AC or DC voltage is applied to the filaments facing the body and arranged close to the substrate , and the filaments are heated to 1600 ° C to 2500 ° C.
The <br/> both a so as to facilitate release and gas decomposition thermal electrons, continuous high frequency is applied to the first flat electrode, the more boron or boron and nitrogen as a sputtering into the gas phase And the substrate is heated to 300 by the heating means of the second flat plate type electrode.
A method for forming cubic boron nitride, which comprises heating the substrate to 1000C to 1000C to form boron nitride on the substrate. 4. After evacuating the inside of the vacuum chamber , argon and hydrogen are mixed into the vacuum chamber, and a gas in which ammonia is mixed is continuously supplied, and the partial pressure ratio of the argon gas to the total gas pressure is 10. % To 90 %, ammonia partial pressure and hydrogen
The ratio of the partial pressure of ammonia against the sum of the partial pressures of 4 to 70%
And the pressure in the vacuum chamber is 0.1 Pa to 1500
After reaching Pa, boron or hexagonal nitride arranged oppositely.
A first plate-type electrode equipped with a target containing boron as a main component and a heating means are provided, and the base is faced to the target.
The tag is interposed between the second flat plate type electrode on which the body is placed .
Target and the substrate facing the substrate and close to the substrate.
AC or DC voltage is applied to the placed filament and the filament is heated to 1600 ° C to 2500 ° C.
Discharges thermoelectrons at high temperature to accelerate gas decomposition
As well as to so that, the high frequency is applied to the first flat electrode, sputtered containing or boron and nitrogen should be constituent elements of the target was continuously fed into the gas phase by a substrate 300 ° C. to A method for forming cubic boron nitride, which comprises heating to 1000 ° C. to form boron nitride on a substrate. 5. After evacuating the inside of the vacuum chamber, argon and hydrogen are mixed into the vacuum chamber, and a gas in which nitrogen is mixed is continuously supplied, and the partial pressure ratio of the argon gas to the total gas pressure is 1.
0% to 90 %, the ratio of the nitrogen partial pressure to the sum of the nitrogen partial pressure and the hydrogen partial pressure is 2% to 50%, and after filling until the pressure in the vacuum chamber reaches 0.1 Pa to 1500 Pa, The inside of the vacuum chamber was hermetically sealed, and then a target mainly composed of hexagonal boron nitride was placed opposite to the target.
Equipped with a first flat plate electrode and heating means
Intervening between the second flat plate type electrodes on which the substrate is placed facing the
Facing the target and the substrate and the substrate
The filament placed close to the
Thermoelectrons at high temperature by heating from 0 ℃ to 2500 ℃
Together with so as to facilitate and gas decomposition release, a high frequency is applied to the first plate electrodes, to supply oxygen and nitrogen should be constituent elements of the target to the continuous gas phase by sputtering, the substrate To 300 to 1000 ℃
A method for forming cubic boron nitride, which comprises continuously forming boron nitride on a substrate. 6. After evacuating the inside of the vacuum chamber, argon and hydrogen are mixed into the vacuum chamber, and a gas in which ammonia is mixed is continuously supplied, and the partial pressure ratio of the argon gas to the total gas pressure is 10%. To 90 %, the ratio of the ammonia partial pressure to the sum of the ammonia partial pressure and the hydrogen partial pressure is 4% to 70%, and the pressure in the vacuum chamber is 0.1 Pa to 1500 P.
After filling until reaching a, the inside of the vacuum chamber is sealed,
Later, the main component was hexagonal boron nitride, which was placed facing each other.
First flat plate type electrode equipped with a target for heating and heating means
The target and the substrate interposed between a second flat plate type electrode having a substrate facing the target and having a substrate mounted thereon.
Heating the filament facing the body and close to the substrate to 1600 ° C to 2500 ° C by energization .
To release thermoelectrons at high temperature and accelerate gas decomposition
As well as the, the high frequency is applied to the first plate electrodes, continuously gas phase Chuhe supplied by sputtering containing and nitrogen should be constituent elements of the target, the substrate 300 ° C.
A method for forming cubic boron nitride, which comprises heating the substrate to 1000 ° C. to continuously form boron nitride on the substrate.