High-strength pure boron target material and manufacturing method thereof

Abstract

The invention relates to a high-strength pure boron target material and a manufacturing method thereof. Boron powder and graphite powder are adopted as raw materials and are sequentially subjected to primary granulation, secondary granulation and normal-temperature pressing to obtain a second round cake, the diameter of the second round cake is larger than 80 mm, and the density reaches 30%-40%; then the second round cake is put into a hot isostatic press to be subjected to high-temperature static pressing, and the compactness of the prepared second round cake is 80%-95%; therefore, compared with the mode that sintering is conducted after mold pressing, the density of a large-diameter product can only reach 60%, the remarkable effect is achieved, the strength of the high-strength pure boron target material is improved, and the high-strength pure boron target material has the advantages of being high in purity and density, uniform in component and organization structure and small in grain size. The manufacturing process is relatively simple, and the cost is low.

Description

Technical Field

[0001] This application relates to the technical field of sputtering target preparation, and particularly relates to a high-strength pure boron target and a manufacturing method thereof. Background Art

[0002] At present, a coating target is a sputtering source that forms various functional thin films on a substrate by magnetron sputtering, multi-arc ion plating or other types of coating systems under appropriate process conditions. Simply put, a target is a target material bombarded by high-speed energetic particles.

[0003] In some related technologies, the semiconductor industry has the most stringent requirements for the quality of sputtered thin films of targets; wafer manufacturers require large size, high purity, low segregation and fine grains for targets, which requires the manufactured targets to have better microstructures. The crystal particle diameter and uniformity of targets have been considered key factors affecting the film deposition rate.

[0004] In other related technologies, an electric kettle, as an essential carrier for boiling water, not only needs to quickly heat the water but also ensure the health and safety of the water quality during the heating process. Therefore, the quality of the electric kettle directly affects the quality of the water. In addition, the materials of health kettles are basically standard high borosilicate glass, and the thicker the glass, the better; secondly, it is the material of the heating plate of the health kettle. There is an inorganic titanium-magnesium ceramic composite coating on the high borosilicate at the bottom of the kettle body; this inorganic titanium-magnesium ceramic composite coating realizes heat conduction in the form of infrared rays and surface radiation. While the temperature of the coating at the bottom of the kettle quickly rises, a high borosilicate at the bottom of the kettle body will form an electrode region, thereby increasing the activity and conductivity of water molecules. When the high borosilicate at the bottom of the kettle body is used as a target for coating, the crystal particle diameter and uniformity of the target have been considered key factors affecting the film deposition rate; it is very difficult to make boron powder with a purity of 99.999% and a diameter of more than 80 mm; in addition, the density of boron powder with a diameter of 80 mm prepared by a conventional sintering method can only reach 60%, and the strength is low. Summary of the Invention

[0005] The embodiments of this application provide a high-strength pure boron target and a manufacturing method thereof to solve the problems in related technologies that it is very difficult to make boron powder with a purity of 99.999% and a diameter of more than 80 mm; in addition, the density of boron powder with a diameter of 80 mm prepared by a conventional sintering method can only reach 60%, and the strength is low.

[0006] In the first aspect, a high-strength pure boron target is provided, which is a product obtained by using boron powder and graphite powder as raw materials, successively through primary granulation, secondary granulation and cold pressing, and then putting it into a hot isostatic press for high-temperature isostatic pressing.

[0007] Further, the purity of the boron powder is 99.999%; the purity of the graphite powder is 99.999%, and the particle size is 2000 mesh; the mass ratio of the graphite powder is 3% - 8%, and the mass ratio of the boron powder is 92% - 97%.

[0008] Further, the high-strength pure boron target is applied to the surfaces of glass, metal, and plastic.

[0009] In a second aspect, a manufacturing method of a high-strength pure boron target is provided, which includes the following steps:

[0010] Step S1: Put the mixture of boron powder and graphite powder into a first mold and press it to form a first round cake with a diameter of 25 mm and a height of 5 mm, and break the first round cake to form a first product; the first product is particles with a size of 1 - 3 mm;

[0011] Step S2: Use a cold isostatic press to apply pressure to the first product; after the pressure application ends, break it again to form a second product; the second product is particles with a size of 2 - 5 mm;

[0012] Step S3: Put the second product into a second mold and press it to form a second round cake;

[0013] Step S4: Seal the second round cake and put it into a hot isostatic press, and apply pressure. The second round cake after pressure application is used as the high-strength pure boron target.

[0014] Further, the inner diameter of the first mold in step S1 is 25 mm; the density of the first round cake is 19% - 25%.

[0015] Further, in step S1, the mixture of boron powder and graphite powder is put between the first molds to dry the boron powder and graphite powder.

[0016] Further, in step S2, using a cold isostatic press to apply pressure to the first product specifically includes the following steps:

[0017] Put the first product into a plastic bag and seal it;

[0018] Put the sealed first product into a cold isostatic press, and then apply pressure at a pressure of 100 MPa for 1.5 hours;

[0019] The density of the second product is 35% - 45%.

[0020] Further, in step S3, putting the second product into the second mold and pressing it to form a second round cake specifically includes the following steps:

[0021] Put the second product into a second mold with a diameter of 85 mm, and then apply pressure at a pressure of 50 MPa for 10 seconds;

[0022] Demold to obtain a second round cake with a density of 30% to 40%.

[0023] Furthermore, in step S4, the second round cake is sealed and then placed in a hot isostatic press, and pressure is maintained. The second round cake after pressure maintenance is used as a high-strength pure boron target, which specifically includes the following steps:

[0024] Seal the second round cake and place it in a hot isostatic press;

[0025] Then maintain it at a pressure of 120 MPa and a temperature of 1450 °C for 1 hour. The second round cake after pressure maintenance is used as a high-strength pure boron target; the density of the second round cake after pressure maintenance is 80% to 95%.

[0026] Furthermore, the method for manufacturing the high-strength pure boron target further includes the following steps:

[0027] After step S4, perform cutting on the second round cake after pressure maintenance to obtain the target finished product.

[0028] The beneficial effects brought by the technical solution provided in this application include:

[0029] The embodiment of this application provides a high-strength pure boron target and a manufacturing method thereof. Since the diameter of the second round cake obtained after primary granulation, secondary granulation, and cold pressing in sequence exceeds 80 mm, and the density reaches 30% to 40%; then the second round cake is placed in a hot isostatic press for high-temperature hydrostatic pressing, and the density of the second round cake after preparation is 80% to 95%; thus, compared with the case where the density of large-diameter products can only reach 60% by the method of die pressing and then sintering, it has a significant effect, improves the strength of the high-strength pure boron target, and has the characteristics of high purity, high density, uniform composition and microstructure, and small grain size; the manufacturing process is relatively simple and the cost is low. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic flow chart of the method for manufacturing a high-strength pure boron target provided by the embodiment of this application. Detailed Embodiments

[0032] The following further describes the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation on the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] It is very difficult to make boron powder with a purity of 99.999% into a diameter of more than 80 mm conventionally; in addition, the density of boron powder with a diameter of 80 mm prepared by the conventional sintering method can only reach 60%, and the strength is low.

[0034] Among them, the main reason is that generally after molding and then sintering (including spark plasma sintering), the product diameter does not exceed 30 mm, and the density can reach 90%. However, when the diameter reaches 70 mm, sintering is difficult to be completely synchronous, and it is difficult to improve the density.

[0035] To solve the above problems, the embodiments of the present application provide a high-strength pure boron target and its manufacturing method to solve the problems in the related art that it is very difficult to make boron powder with a purity of 99.999% into a diameter of more than 80 mm; in addition, the density of boron powder with a diameter of 80 mm prepared by the conventional sintering method can only reach 60%, and the strength is low.

[0036] Please refer to Figure 1 , a high-strength pure boron target, which is a product obtained by using boron powder and graphite powder as raw materials, successively through primary granulation, secondary granulation and cold pressing at room temperature, and then putting it into a hot isostatic press for high-temperature isostatic pressing.

[0037] The purity of the boron powder is 99.999%; the purity of the graphite powder is 99.999%, and the particle size is 2000 mesh; the mass ratio of the graphite powder is 3% - 8%, and the mass ratio of the boron powder is 92% - 97%.

[0038] A manufacturing method of a high-strength pure boron target, which includes the following steps:

[0039] Step S1: Put the mixture of boron powder and graphite powder into the first mold and press it to form a first round cake with a diameter of 25 mm and a height of 5 mm, and break the first round cake to form a first product; the first product is particles with a size of 1 - 3 mm;

[0040] Step S2: Use a cold isostatic press to keep the pressure on the first product; after the pressure holding is completed, break it again to form a second product; the second product is particles with a size of 2 - 5 mm;

[0041] Step S3: Put the second product into the second mold and press it to form a second round cake; at this time, the second round cake will have a certain density but low strength, so the subsequent step S4 is required.

[0042] Step S4: Seal the second round cake and place it in a hot isostatic press, and perform pressure holding. The pressure-held second round cake is used as a high-strength pure boron target.

[0043] The diameter of the second round cake obtained after primary granulation, secondary granulation, and cold pressing in sequence exceeds 80 mm, and the relative density reaches 30% - 40%; then the second round cake is placed in a hot isostatic press for hot isostatic pressing, and the relative density of the second round cake after preparation is 80% - 95%; thus, compared with the case where the relative density of large-diameter products can only reach 60% by the method of die pressing followed by sintering, it has a significant effect, improves the strength of the high-strength pure boron target, and has the characteristics of high purity, high relative density, uniform composition and microstructure, and fine grain size; the manufacturing process is relatively simple and the cost is low.

[0044] In some preferred embodiments, the inner diameter of the first mold in step S1 is 25 mm; the relative density of the first round cake is 19% - 25%. In step S1, the mixture of boron powder and graphite powder is placed between the first molds to dry the boron powder and graphite powder. The mixture needs to be fully mixed.

[0045] In step S2, the cold isostatic press is used to perform pressure holding on the first product, which specifically includes the following steps: placing the first product in a plastic bag and sealing it; placing the sealed first product in a cold isostatic press, and then performing pressure holding at a pressure of 100 MPa for 1.5 hours; the relative density of the second product is 35% - 45%.

[0046] In step S3, the second product is placed in a second mold to be pressed into a second round cake, which specifically includes the following steps: placing the second product in a second mold with a diameter of 85 mm, and then performing pressure holding at a pressure of 50 MPa for 10 seconds; demolding to obtain a second round cake with a relative density of 30% - 40%.

[0047] In step S4, the second round cake is sealed and placed in a hot isostatic press, and pressure holding is performed. The pressure-held second round cake is used as a high-strength pure boron target, which specifically includes the following steps: sealing the second round cake and placing it in a hot isostatic press; then maintaining it at a pressure of 120 MPa and a temperature of 1450 °C for 1 hour, and using the pressure-held second round cake as a high-strength pure boron target; the relative density of the pressure-held second round cake is 80% - 95%.

[0048] In some preferred embodiments, the inner diameter of the first mold in step S1 is 25 mm; the relative density of the first round cake is 20%. In step S1, the mixture of boron powder and graphite powder is placed between the first molds to dry the boron powder and graphite powder.

[0049] In step S2, the first product is pressure-maintained by a cold isostatic press, which specifically includes the following steps: putting the first product into a plastic bag and sealing it; putting the sealed first product into the cold isostatic press, and then pressure-maintaining it at a pressure of 100 MPa for 1.5 hours; the density of the second product is 40%.

[0050] In step S3, the second product is put into a second mold and pressed to form a second round cake, which specifically includes the following steps: putting the second product into a second mold with a diameter of 85 mm, and then pressure-maintaining it at a pressure of 50 MPa for 10 seconds; demolding to obtain a second round cake with a density of 30% - 40%.

[0051] In step S4, the second round cake is sealed and then put into a hot isostatic press for pressure-maintaining, and the pressure-maintained second round cake is used as a high-strength pure boron target, which specifically includes the following steps: sealing the second round cake and putting it into the hot isostatic press; then maintaining it at a pressure of 120 MPa and a temperature of 1450 °C for 1 hour, and using the pressure-maintained second round cake as a high-strength pure boron target; the density of the pressure-maintained second round cake is 90%.

[0052] In some preferred embodiments, the method for manufacturing a high-strength pure boron target further includes the following steps:

[0053] After step S4, the pressure-maintained second round cake is subjected to cutting processing to obtain a target finished product. That is, the bottom of the kettle body made of high borosilicate is obtained.

[0054] The above cold isostatic press places the material loaded into a sealed and elastic mold in a container filled with liquid or gas, applies a certain pressure to it with the liquid or gas, presses the material into a solid to obtain a blank with the original shape. After the pressure is released, the mold is taken out of the container, and after demolding, the blank is further shaped as needed. The cold isostatic press is an existing device.

[0055] The hot isostatic press is an instrument and equipment that uses the hot isostatic pressing technology in a high-temperature and high-pressure sealed container, uses high-pressure argon gas as the medium, and applies an isotropic equal static pressure to the powder or sintered blank (or part) to be compacted in it to form a high-density blank (or part). The hot isostatic press is an existing device.

[0056] For the device for crushing in the above steps, no specific limitation is made, and it only needs to meet the crushing requirements for particles of 2 - 5 mm and particles of 1 - 3 mm.

[0057] The above has described the embodiments of the present invention in detail with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principles and spirit of the present invention, various changes, modifications, substitutions, and variations made to these embodiments still fall within the protection scope of the present invention.

Claims

1. A high-strength pure boron target, characterized in that: The product is prepared by using boron powder and graphite powder as raw materials, sequentially undergoing primary granulation, secondary granulation and pressing at room temperature, and then placing the granules in a hot isostatic press for high-temperature static pressing.

2. The high-strength pure boron target material according to claim 1, characterized in that: The purity of the boron powder is 99.999%; the purity of the graphite powder is 99.999% and the particle size is 2000 meshes; the mass ratio of the graphite powder is 3% to 8%, and the mass ratio of the boron powder is 92% to 97%.

3. The high-strength pure boron target material according to claim 1, characterized in that: The high-strength pure boron target material is applied to the surfaces of glass, metal and plastic.

4. A method for manufacturing a high-strength pure boron target material as claimed in any one of claims 1 to 3, characterized in that: It includes the following steps: Step S1, placing a mixture of boron powder and graphite powder into a first mold and pressing to form a first round cake with a diameter of 25 mm and a height of 5 mm, and crushing the first round cake to form a first product; the first product is 1-3 mm particles; Step S2, using a cold isostatic press to hold the first product under pressure; after the holding period, the first product is crushed again to form a second product; the second product is particles of 2 to 5 mm; Step S3, placing the second product into a second mold and pressing it to form a second round cake; Step S4, sealing the second round cake and placing it in a hot isostatic press, and maintaining the pressure, and using the second round cake after the pressure maintenance as a high-strength pure boron target.

5. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: The inner diameter of the first mold in step S1 is 25 mm; the density of the first round cake is 19-25%.

6. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: In the step S1, a mixture of boron powder and graphite powder is placed between the first molds to dry the boron powder and graphite powder.

7. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: In the step S2, the first product is pressurized by using a cold isostatic press, which specifically includes the following steps: Put the first product into a plastic bag and seal it; The sealed first product was placed in a cold isostatic press and then maintained at a pressure of 100 MPa for 1.5 hours; The density of the second product is 35% to 45%.

8. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: In step S3, the second product is placed in a second mold and pressed into a second round cake, which specifically includes the following steps: The second product was placed in a second mold with a diameter of 85 mm, and then maintained at a pressure of 50 MPa for 10 seconds; The second round cake with a density of 30% to 40% is obtained by demoulding.

9. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: In the step S4, the second round cake is sealed and placed in a hot isostatic press, and the pressure is maintained, and the second round cake after the pressure maintenance is used as a high-strength pure boron target material, which specifically includes the following steps: The second round cake is sealed and placed in a hot isostatic press; Then, the pressure is maintained at 120 MPa and the temperature is maintained at 1450 degrees Celsius for 1 hour, and the second round cake after the pressure maintenance is used as a high-strength pure boron target material; the density of the second round cake after the pressure maintenance is 80% to 95%.

10. The method for manufacturing a high-strength pure boron target material according to claim 4, characterized in that: The method for manufacturing a high-strength pure boron target material further comprises the following steps: After step S4, the second round cake after pressure maintenance is subjected to cutting processing to obtain a target finished product.

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