The method of manufacture of the plates and/or sheets of foil anisotropic pyrolytic boron nitride, the foil sheet made in this way, the product of anisotropic pyrolytic boron nitride in the form of a pack of plates and/or sheets of foil and method thereof

 

(57) Abstract:

The invention relates to a technology of manufacturing products of high temperature dielectric, insulating materials and technologies of their production by chemical vapor deposition from the gas phase for the manufacture of various components for microwave applications and integrated circuits. The inventive plate and/or foil sheets of boron nitride is produced by the formation on the substrate in the reactor package contains parallel layers of boron nitride, by repeated alternation of the process of chemical vapor deposition of boron nitride from the gas phase by the interaction of boron TRIFLUORIDE and ammonia and processing the surface of the deposited layer of boron nitride for at least 15 min at the same temperature and pressure gaseous agent, pestiviruses active centers of crystallization of the surface layer formed of boron nitride with the formation of the boundary, and then the resulting package mechanical break down the boundaries of the partition plates and/or sheets of foil. As gaseous agent use ammonia, nitrogen, hydrogen, methane, helium, argon, and mixtures thereof. The invention allows to obtain a plate, foil sheets and articles made of boron nitride is of GLA.

The invention relates to a technology of manufacturing products of high temperature dielectric, insulating materials, namely the products of anisotropic pyrolytic boron nitride and technologies of their production by chemical vapor deposition from the gas phase, namely, plates and/or sheets of foil and package consisting of them.

Plates and/or sheets of foil pyrolytic boron nitride is used for the manufacture of various parts, in particular rod-heatsinks for appliances, microwave appliances, solid planar sources of boron for the production of integrated circuits, as well as dielectric spacers powerful capacitors, replacing natural mica "Muscovite".

The pack of plates and/or sheets of foil pyrolytic boron nitride can be used for transportation and storage of such plates and/or sheets of foil.

A known method of manufacturing plates of anisotropic pyrolytic boron nitride by chemical vapor deposition of boron nitride in the interaction of gaseous flows trichloride boron and ammonia at a temperature of 1890oC and a pressure of approximately 0.5 mm Hg (RF patent N 2093964, (example 2) CL C 01 B the chemical deposition from the gas phase boron nitride in the interaction of gaseous streams of boron TRIFLUORIDE and a mixture gas of nitrogen and hydrogen at a temperature of 2000oC and a pressure of 0.4-0.6 mm Hg (U.S. patent 3131089, class C 01 B 21/064, 1964), or boron TRIFLUORIDE and ammonia at a temperature 1750-1950oC and a pressure of 5-8 mm Hg (N. Dist. Sarapin, R. Y. Mametov, E. C. Tupitsyn Has Correctly Noted. "Study of the formation of boron nitride in gas-phase processes. - Abstracts of the International conference "boron Nitride. The receipt. Properties. Applications". Obninsk, 1993, S. 18-19).

The disadvantages of the known methods of manufacture plates can be attributed to the inability to obtain plates of boron nitride with a thickness less than 0.3 mm, i.e., sheets of foil, for violating their integrity when removed from the substrate, and the inefficiency of the manufacturing process due to insufficient use of the deposition surface.

The closest in technical essence to the present invention is a method of manufacturing plates and/or sheets of foil anisotropic pyrolytic boron nitride by education on the substrate in the reactor package contains parallel layers of anisotropic pyrolytic boron nitride and positioned between the intermediate layers of material having properties different from the properties of boron nitride, in particular pyrolytic graphite, molybdenum, tantalum, aluminum nitride (U.S. patent 3310375, CL 23-191, 1967). Katrina boron in the interaction of gaseous trichloride boron and ammonia at a temperature 1775-1800oC and a pressure of 0.3 mm Hg and process of chemical deposition from the gas phase, for example, pyrolytic graphite or aluminum nitride at a temperature required for deposition. To obtain sheets of foil package with a thickness of 0.85-1.14 mm, containing 5-6 layers of boron nitride, after cooling and removal from the substrate is treated with a concentrated solution of sulfuric acid with the addition of nitric acid or sodium hydroxide, or potassium hydroxide for dissolving the intermediate layer. The sheets of foil having a thickness of 0.08 to 0.13 mm are washed with water and dried.

The disadvantages of the known methods of producing sheets of foil are its complexity, a multi-stage, low-tech and large amounts of toxic waste, because its implementation requires repetitive change in temperature during the deposition of intermediate layers, in particular decreasing the temperature from 1800oC to 1000oC when the deposition layer of aluminum nitride, and the use of special stage chemical treatment package concentrated acids or alkalis, as well as the use of large quantities of toxic reagents.

In addition, the package obtained in a known manner, is not the final product, which more when carrying out one of the stages of the process (deposition) and used at its different stages (dissolution of intermediate layers).

Known foil sheets anisotropic pyrolytic boron nitride with a thickness of 0.3-0.5 mm, a density of 2.10-2.20 g/cm3used as a dielectric and insulating materials, and are obtained directly in the reactor chemical deposition of boron nitride in the interaction of trihalogen boron and ammonia. These foil sheets of boron nitride have the strength to break 100-160 kV/mm (N. Dist. Sarapin "Structure and properties of paroniria boron. In the collection of articles "Chemical vapor deposition of refractory inorganic materials". L. : ed. Giph, 1976, S. 73,93).

The disadvantage of foil sheets of boron nitride is sufficiently high breakdown strength, which limits their use as electrical insulation and dielectric material.

The present invention is to simplify the technology for plates and/or sheets of foil boron nitride, obtaining foil sheets of boron nitride with high breakdown strength, the receipt of the package containing easily divided plates and/or sheets of foil pyrolytic boron nitride, as products ready for delivery to the customer, as well as the development of technology for manufacturing such a package.

In addition, as a gaseous agent is used as a compound selected from the group consisting of ammonia, methane, nitrogen, hydrogen, helium, argon or mixtures thereof, to form a package from 2-10 plates and/or sheets of foil pyrolytic boron nitride with a thickness of 0.05 mm to 2.0 mm, consisting of plates and/or sheets of foil the same or different thickness. In this case, the deposition from the gas phase nitride Bo the AC supply their gas flows in the reactor is carried out at a ratio of 1: 1 to 1: 6.

The task is achieved by the fact that the sheets of foil anisotropic pyrolytic boron nitride is used as a dielectric and insulating material obtained directly in the reactor by forming on a substrate a package from them by repeated alternation of the process of chemical vapor deposition of a layer of boron nitride in the interaction of gaseous boron TRIFLUORIDE and ammonia and processing the surface of the deposited layer of boron nitride gaseous agent prior to the formation of boundaries and subsequent mechanical breakdown of package interfaces with a thickness of 0.05-0.5 mm and a density of 2.10-2.20 g/cm3have the strength at break of 300 to 400 kV/mm

The task is achieved by the fact that the product of anisotropic pyrolytic boron nitride in the form of parallel package mechanical divided by the boundary 2-10 plates and/or sheets of foil boron nitride with a thickness of 0.05 - 2.0 mm, a density of 2.10 - 2.20 g/cm3and strength at break of 300 to 400 kW, obtained by repeated alternation of the process of chemical vapor deposition of boron nitride from the gas phase by the interaction of boron TRIFLUORIDE and ammonia and processing the surface of the deposited layer is argon or mixtures thereof, prior to the formation of interfaces.

In addition, the product is made in the form of a pack of plates and/or sheets of foil the same or different thickness.

The task is achieved by the fact that in the known method of manufacturing articles of anisotropic pyrolytic boron nitride by chemical deposition from the gas phase boron nitride on a substrate in a reactor to form a package of parallel plates and/or sheets of foil boron nitride, by repeatedly alternating process of chemical vapor deposition of boron nitride in the interaction of gaseous boron TRIFLUORIDE and ammonia at elevated temperature and reduced pressure, and processing the surface of the deposited boron nitride for at least 15 minutes at the same temperature and pressure gaseous agent selected from the group consisting of ammonia, nitrogen, hydrogen, methane, helium, argon or mixtures thereof with the formation of the interface.

In addition, form the package from 2-10 plates and/or sheets of foil with a thickness of 0.05 to 2.0 mm, consisting of plates and/or sheets of foil the same or different thickness. In this case, the deposition from the gas phase boron nitride is carried out at a temperature of 1750 - 2000oC, a pressure of 1 to 3 mm Hg, and for the interaction of the P CLASS="ptx2">

The advantages of the proposed method of manufacture of the plates and/or sheets of foil anisotropic boron nitride is that it greatly simplified in comparison with the known, because when using it, no need to change the temperature in the reactor and to produce a complex process of liquid-phase chemical separation package on a plate using a large number of corrosive and toxic liquids, which then go into waste. This is possible because obtained by the proposed method, the package is easily separated by mechanical means on a plate on the limits of the section.

In addition, when using the proposed method, you can get the sheets of foil with a thickness of 0.05 to 0.5 mm and a plate thickness of more than 0.5 mm to 2.00 mm at the same time.

Foil sheets of pyrolytic boron nitride obtained by the proposed method, with a thickness of 0.05 to 0.5 mm, have a significantly higher resistance to breakdown (more than 2 times) than known similar leaves, yet remain at a high level, other dielectric characteristics, so you can use them as spacers high-power capacitors, replacing natural mica "Muscovite", used is a new type product of pyrolytic boron nitride, which splits easily into sheets and/or sheets of foil mechanically, which greatly simplifies the manufacture and transportation, especially thin sheets of foil having a thickness of 0.05 - 0.08 mm, and the sheets of foil obtained from the package, have a high resistance to breakdown, so you can use them as spacers powerful capacitors.

A method of manufacturing a package of plates and/or sheets of foil anisotropic pyrolytic boron nitride is not complicated, technologically advanced and not time consuming because it doesn't require any change of technological parameters of the conventional process of chemical vapor deposition of boron nitride in the gas phase and any additional technological equipment and toxic materials and waste for stage liquid-phase dissolution of intermediate layers.

These technical results are achieved due to the fact that the deposition of the boron nitride is in the interaction of boron TRIFLUORIDE and ammonia in the processing of deposited layer of boron nitride selected gaseous agents. When this occurs, the formation of boundary layers by blocking growth centers due to the chemisorption of gaseous atoms agents on the growth surface is lisalu on new growth centers, and in the package are formed boundary, preventing engagement of the layers when stratifying on individual plates and/or sheets of foil.

In Fig. 1 shows a General view of the reactor used for a package of plates and/or sheets of foil pyrolytic boron nitride, Fig. 2 is a micrograph of a polished section of the end face of the package containing the foil sheets of boron nitride, with a separating layer of pyrolytic carbon and boundary obtained according to the invention (a) compared with the micrograph of the cut end face of the end plate standard pyrolytic boron nitride (in) without borders section.

For a package of plates and/or sheets of foil pyrolytic boron nitride is used reactor (Fig. 1), which is an oven in stainless steel. The reactor includes a housing 1, a pipe 2 to enter boron TRIFLUORIDE, the pipe 3 to the input of ammonia and other gaseous reactants in the deposition chamber 4 within which is placed a flat substrate 5 and the pipe 6 to the output of the exhaust gases.

The pipe 2 into the chamber 4 of deposition served boron TRIFLUORIDE. At the same time the pipe 3 into the chamber 4 deposition is ammonia, where it is mixed with the stream of boron TRIFLUORIDE. In the chamber 4 osazhdeniem from the gas phase layer of boron nitride on the substrate 5 at a pressure of 1 - 3 mm Hg.

After deposition of the layer of boron nitride for 0.5 - 20 hours depending on the required thickness of the plate and/or foil sheet of boron nitride, which may be from 0.05 to 2.0 mm, the supply of boron TRIFLUORIDE and ammonia is terminated and the growth surface is formed of a layer of boron nitride is processed under the same temperature and pressure of the flow of the gaseous agent for at least 15 minutes, which is served by the pipe 3. As gaseous agents are ammonia, nitrogen, hydrogen, methane, helium, argon or mixtures thereof. In the chamber 4 deposition of gaseous agent chemisorbents the growth surface of boron nitride, blocking and destroying the active growth centers, and in the next layer of boron nitride crystallization starts on new growth centers, which leads to the formation of the interface between the layers, preventing engagement of the layers when the delamination of the package. On the substrate 5 are formed packages from separate plates and/or sheets of foil boron nitride.

Feed streams BF3and NH3is carried out at a ratio of 1: 1 to 1: 6, and the supply of gaseous agents is a flow of 40 l/h 240 l/h.

Gases from the reactor are removed by pipe 6.

These studies 10 times, creating on the substrate 5 packages from 2-10 plates and/or sheets of foil boron nitride.

After cooling and removal of packages from the substrate 5 is made of their simple mechanical separation at the boundary of the partition plates and/or sheets of foil. When used as a gaseous agent of methane or its mixtures with other gases remains of an intermediate layer of pyrolytic carbon are removed by annealing in air in a muffle furnace at a temperature of 600-800oC.

Below are examples illustrating the invention.

Example 1.

The deposition chamber 4 is heated to a temperature of 1850oC and vacuum until a pressure of 2 mm Hg. The nozzles 2 and 3 are served accordingly, the stream of boron TRIFLUORIDE with a flow rate of 80 l/h and the flow of ammonia with a flow rate of 160 l/h.

In the deposition chamber 4 by mixing ammonia with boron TRIFLUORIDE is their interaction with the deposition of a layer of boron nitride on the substrate 5 made of graphite. The deposition process is conducted for 1 hour. Then the supply of boron TRIFLUORIDE cease and growth surface of the formed layer is treated under the same temperature and pressure for 15 minutes ammonia. This process of deposition of boron nitride with subsequent treatments is Yes boron. After cooling the reactor, the packet is removed from the substrate, and then mechanically separated into leaves on the boundary. The resulting foil sheets have a thickness of 0.10 mm, the density of boron nitride, as defined by GOST 15139-89, section 3, is 2.10 g/cm3the strength test is defined by OST 027006-75, is 360 kV/mm, the specific resistivity, as determined by OCT 027.700-80 "inorganic Dielectrics. Method of determining the specific volume resistivity", - 0.81017The Mme. The dielectric constant and tangent of dielectric loss angle defined by OST 027.042-80 "inorganic Dielectrics. The method of determining the relative permittivity and tangent of dielectric loss angle range from 2.5 to 3.3 THZ", - 3.6 and 1,210-4respectively.

The process parameters and the parameters of the received packets of boron nitride from this example and all subsequent examples are shown in table 1.

Examples 2 to 8.

Receiving packets and foil sheets of boron nitride is carried out as in example 1 by changing the supplied gaseous agent.

Examples 9-13.

Receiving packets and foil sheets of boron nitride perform as well as note the">

Examples 14-18.

Receiving packets and foil sheets of boron nitride is carried out as in example 1, by changing the pressure in the deposition chamber 4 and the ratio of the flow fed boron TRIFLUORIDE and ammonia.

Examples 19-24.

Receiving packets and foil sheets of boron nitride is carried out as in example 1, varying the time of deposition of the layer of boron nitride and the number of alternations of the deposition of boron nitride and process the surface of the formed layer.

Example 25.

The deposition chamber 4 is heated to a temperature of 1800oC and vacuum up to a pressure of 1 mm Hg. The nozzles 2 and 3 are served accordingly, the stream of boron TRIFLUORIDE with a flow rate of 100 l/h and the flow of ammonia with a flow rate of 300 l/h. In the chamber 4 by the interaction of boron TRIFLUORIDE ammonia is deposited from the gas phase layer of boron nitride on the substrate 5 made of graphite for 5 hours. Then the supply of boron TRIFLUORIDE and ammonia cease and growth surface layer formed of boron nitride treated at the same temperature and pressure with hydrogen, which is fed by pipe 4 with a flow rate of 240 l/h for 20 minutes.

The process of deposition of boron nitride and the surface of the formed layer is W ill result splitting plates on the boundary. Get two plates of a thickness of 0.53 mm

Examples 26 to 27.

Packages and plates of boron nitride get in the same way as described in example 25, by changing the time of deposition of the boron nitride and the number of alternations of the deposition of the layer of boron nitride and process for surface treatment layer formed of boron nitride nitrogen gas.

Example 28.

Camera 5 deposition is heated to a temperature of 1800oC and vacuum up to a pressure of 2 mm Hg. The nozzles 2 and 3 are served accordingly, the stream of boron TRIFLUORIDE with a flow rate of 120 l/h and the flow of ammonia with a flow rate of 480 l/h. In the chamber 4 by the interaction of boron TRIFLUORIDE and ammonia is deposited from the gas phase boron nitride on flat graphite substrates for 0.5 hours. Then the supply of boron TRIFLUORIDE and ammonia ceased. The pipe 3 in the deposition chamber 4 serves nitrogen, flow rate which is 120 l/h, and treated them growth surface layer formed of boron nitride for 25 minutes to form the boundary.

The process of deposition of boron nitride and process for surface treatment layer formed of boron nitride under the conditions specified above, alternate 4 times.

After that, the flow of nitrogen is stopped and the influence of boron TRIFLUORIDE ammonia deposition from the gas phase boron nitride on substrates is carried out for 10 hours, then produce a surface treatment layer formed of boron nitride with nitrogen for 25 minutes by nitrogen supply by the pipe 3 into the chamber 4 with the formation of the boundary. The process of deposition of boron nitride on the substrate and a surface layer formed of boron nitride was repeated once more under the same conditions. On the substrate thus receive packages, consisting of 5 sheets and 2 plates of boron nitride. After cooling the reactor, the received packet is removed from the substrate. Received packets of boron nitride can be easily mechanically divided into sheets and plates of boron nitride.

Example 29 (comparative).

Package of boron nitride get in the same way as described in example 6, but instead of boron TRIFLUORIDE use trichloride boron. Precipitated package containing 10 layers of boron nitride, which cannot be divided, because of their healing through the intermediate phase (B4C) generated during the processing of the growth surface of the layer of boron nitride methane. The resulting layers cannot be separated by mechanical means, because they have no boundaries. This is due to lower than that of boron TRIFLUORIDE, thermostability of trichloride boron, which at the temperature of deposition on the growth of PowerGrid boron.

Example 30 (comparative).

Package of boron nitride get in the same way as described in example 29, but instead of methane using ammonia as a gaseous agent and processing them hold for 25 minutes. Get the same service as in example 29, the layers of which it is impossible to separate the purely mechanical way because of their intergrowths.

Tables 1 and 2 explain the present invention.

1. The method of manufacture of the plates and/or sheets of foil anisotropic boron nitride by education on the substrate in the reactor package contains parallel layers of boron nitride obtained by chemical deposition from the gas phase in the interaction of gaseous trihalogen boron and ammonia at elevated temperature and reduced pressure, followed by separation of the layers, characterized in that what layers in the package is formed in the form of plates and/or sheets of foil, by repeatedly alternating process of chemical vapor deposition of boron nitride from the gas phase by the interaction of boron TRIFLUORIDE and ammonia and processing the surface of the deposited layer of boron nitride for at least 15 min at the same temperature and pressure gaseous agent, pestiviruses active centers of crystallization of the surface of assalut on the limits of the partition plates and/or sheets of foil.

2. The method according to p. 1, characterized in that the gaseous agent is used as a compound selected from the group consisting of ammonia, nitrogen, hydrogen, methane, helium, argon or mixtures thereof.

3. The method according to p. 1 or 2, characterized in that the package, consisting of 2-10 plates and/or sheets of foil boron nitride.

4. The method according to any of paragraphs. 1 to 3, characterized in that the package of plates and/or sheets of foil thickness 0,05 - 2,00 mm

5. The method according to any of paragraphs. 1 to 4, characterized in that the package, consisting of plates and/or sheets of foil of the same thickness.

6. The method according to any of paragraphs. 1 to 3, characterized in that the package, consisting of plates and/or sheets of foil of different thickness.

7. The method according to any of paragraphs. 1 to 5, characterized in that the deposition from the gas phase boron nitride is carried out at a temperature of 1750 - 2000oC.

8. The method according to any of paragraphs. 1 to 7, characterized in that the deposition from the gas phase boron nitride is carried out at a pressure of 1-3 mm Od.

9. The method according to any of paragraphs. 1 to 8, characterized in that the deposition from the gas phase layers of boron nitride of boron TRIFLUORIDE and ammonia is carried out at the ratio of their gas flows from 1: 1 to 1: 6.

transalation material, obtained directly in the reactor by forming on a substrate of the package, by repeatedly alternating process of chemical vapor deposition of boron nitride in the interaction of gaseous boron TRIFLUORIDE and ammonia and processing the surface of the deposited layer of boron nitride gaseous agent prior to the formation of boundaries and subsequent mechanical breakdown of package interfaces with a thickness of 0.05-0.5 mm, a density of 2.10-2.20 g/cm3has the strength to break 300-400 kV/mm

11. The product of anisotropic pyrolytic boron nitride in the form of parallel package mechanical divided by borders section 2-10 of the plates and/or sheets of foil boron nitride with a thickness of 0.05-2.0 mm, a density of 2.10-2.20 g/cm3and strength at break of 300 to 400 kV/mm, obtained by repeated alternation of the process of chemical deposition of a layer of boron nitride from the gas phase by the interaction of boron TRIFLUORIDE and ammonia and processing the surface of the deposited boron nitride gaseous agent selected from the group consisting of ammonia, nitrogen, hydrogen, methane, helium, argon or mixtures thereof, to form a boundary.

12. The product under item 11, in which it is made as a package of plates and/or sheets of foil of different thickness.

14. A method of manufacturing articles of anisotropic pyrolytic boron nitride, characterized in that on the substrate in the reactor to form a package of parallel plates and/or sheets of foil pyrolytic boron nitride, by repeatedly alternating deposition process from the gas phase boron nitride in the interaction of boron TRIFLUORIDE and ammonia at elevated temperature and reduced pressure and the process of processing the surface of a deposited layer of boron nitride for at least 15 min at the same temperature and pressure gaseous agent selected from the group consisting of ammonia, nitrogen, hydrogen, methane, helium, argon or mixtures thereof, with the formation of the boundary.

15. The method according to p. 14, wherein forming the package, consisting of 2-10 plates and/or sheets of foil having a thickness of 0.05 to 2.0 mm

16. The method according to any of paragraphs. 14, 15, characterized in that to form a package consisting of plates and/or sheets of foil of the same thickness.

17. The method according to any of paragraphs. 14, 15, characterized in that to form a package consisting of plates and/or sheets of foil of different thickness.

18. The method according to any of paragraphs. 14 to 17, characterized in that the deposition from the gas phase boron nitride is the Scion phase boron nitride is carried out at a pressure of 1-3 mm Od.

20. The method according to any of paragraphs. 14 to 19, characterized in that for the interaction of boron TRIFLUORIDE and ammonia feed their gas streams are produced at a ratio of 1: 1 to 1: 6.

 

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