Environment-friendly silicon wafer as well as preparation method and application thereof

Abstract

The invention provides an environment-friendly silicon wafer as well as a preparation method and application thereof, and belongs to the technical field of reactive sintering silicon carbide ceramics. The environment-friendly silicon wafer is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5-10 parts of a binder, 8-15 parts of petroleum coke and water, and the binder is an environment-friendly binder and comprises one or more of corn starch, maltose, cane sugar and glucose. The environment-friendly adhesive is used for the silicon wafer, no unpleasant smell exists in the silicon wafer preparation and siliconizing sintering use process, the environment-friendly requirement can be met, and industrial production is facilitated; the use amount of the binder is limited, it can be guaranteed that in the sintering process of the reactive sintering silicon carbide ceramic, after a part of carbon content (solid content) is converted to be sintered, a blank still forms a round shape after silicon is dissolved out, the appearance is not deformed, and the problems that after the binder is sintered, the deformation is large, and the binder cannot be separated from the silicon carbide ceramic to be sintered are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reaction-sintered silicon carbide ceramics, and in particular to an environmentally friendly silicon wafer and a preparation method and application thereof. Background Art

[0002] Reaction-sintered silicon carbide ceramics are widely used in aerospace, semiconductor, and chemical environmental protection fields due to their excellent high-temperature resistance, wear resistance, and low production cost. Currently, reaction-sintered silicon carbide ceramics require densification through siliconization during the sintering process. During high-temperature sintering, silicon powder is placed around or on the surface of a silicon carbide ceramic blank. Molten silicon, above the silicon melting point, infiltrates into the green body along the capillaries of the blank due to surface tension. During siliconization, the silicon reacts with carbon in the green body to form secondary silicon carbide, while some silicon fills the pores, resulting in a dense reaction-sintered silicon carbide ceramic with near-zero porosity. Currently, most reaction-sintered silicon carbide ceramics use silicon powder with a binder containing harmful, odorous organic compounds such as phenolic resin. These binders, such as phenolic resin, generate large amounts of harmful and toxic gases during the degreasing and cracking process, polluting the environment with an unpleasant odor and hindering industrial production. Summary of the Invention

[0003] In view of this, the present invention aims to provide an environmentally friendly silicon wafer and its preparation method and application. The silicon wafer of the present invention uses an environmentally friendly binder, has no unpleasant odor during the silicon wafer preparation and siliconization sintering process, can meet environmental protection requirements, and is beneficial to industrial production.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides an environmentally friendly silicon wafer, which is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5 to 10 parts of a binder, 8 to 15 parts of petroleum coke and water, wherein the binder is an environmentally friendly binder and includes one or more of corn starch, maltose, sucrose and glucose.

[0005] Preferably, the environmentally friendly silicon is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5 to 10 parts of binder, 10 parts of petroleum coke and water.

[0006] Preferably, the environmentally friendly silicon is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 6.8 parts of binder, 10 parts of petroleum coke and water.

[0007] Preferably, the particle size of the silicon powder is 80-300 mesh.

[0008] Preferably, the particle size of the silicon powder is 100-200 mesh.

[0009] The present invention also provides a method for preparing the environmentally friendly silicon wafer described in the above technical solution, comprising the following steps: mixing silicon powder, a binder, petroleum coke and water to obtain a slurry; drying the slurry to obtain a powder; The powder is formed to obtain the environmentally friendly silicon wafer.

[0010] Preferably, the solid content of the slurry is 40-50 wt%.

[0011] Preferably, the drying is spray drying or direct drying, the inlet temperature of the spray drying is 150-180°C, and the outlet temperature is 50-80°C, and the temperature of the direct drying is 60-80°C.

[0012] Preferably, the molding pressure is 15-40 MPa.

[0013] The present invention also provides the use of the environmentally friendly silicon wafer described in the above technical solution or the environmentally friendly silicon wafer prepared by the preparation method described in the above technical solution in the field of reaction-sintered silicon carbide ceramics.

[0014] The present invention provides an environmentally friendly silicon wafer, which is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5 to 10 parts of a binder, 8 to 15 parts of petroleum coke and water, wherein the binder is an environmentally friendly binder and includes one or more of corn starch, maltose, sucrose and glucose.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The silicon wafer of the present invention uses an environmentally friendly binder, and there is no unpleasant odor during the process of silicon wafer preparation and siliconization sintering, which can meet environmental protection requirements and is beneficial to industrial production. In addition, the present invention limits the amount of binder used, which can ensure that a portion of the carbon content (solid content) is converted during the sintering process (siliconization sintering) of preparing reaction-sintered silicon carbide ceramics to achieve that after sintering and silicon dissolution, the embryo remains round in shape and has no deformation in appearance, avoiding the problem of large deformation after sintering of the binder and inability to separate from the sintered silicon carbide ceramics.

[0016] The present invention also provides a method for preparing the environmentally friendly silicon wafer described in the above technical solution. The preparation method of the present invention is simple to operate and suitable for industrial application. DETAILED DESCRIPTION

[0017] The present invention provides an environmentally friendly silicon wafer, which is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5 to 10 parts of a binder, 8 to 15 parts of petroleum coke and water, wherein the binder is an environmentally friendly binder and includes one or more of corn starch, maltose, sucrose and glucose.

[0018] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0019] In the present invention, the environmentally friendly silicon is preferably prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5-10 parts of binder, 10 parts of petroleum coke and water, and more preferably prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 6.8 parts of binder, 10 parts of petroleum coke and water. The present invention limits the amount of binder used, which can ensure that a portion of the carbon content (solid content) is converted during the sintering process of preparing reaction-sintered silicon carbide ceramics to achieve the goal that after sintering and silicon dissolution, the embryo remains round in shape and has no deformation in appearance, avoiding the problem of large deformation of the binder after sintering and inability to separate from the sintered silicon carbide ceramics.

[0020] In the present invention, the binder is preferably corn starch. The silicon wafer of the present invention uses an environmentally friendly binder, which has no unpleasant odor during the process of silicon wafer preparation and siliconization and sintering, can meet environmental protection requirements, and is beneficial to industrial production.

[0021] In the present invention, the particle size of the silicon powder is preferably 80-300 mesh, more preferably 100-200 mesh, specifically 80, 100, 150, 200, 250 or 300 mesh.

[0022] In the present invention, the water is preferably deionized water.

[0023] In the present invention, the silicon powder preferably does not contain boron nitride, which will not cause boron doping and contamination of silicon carbide ceramic products, and can be used in specific semiconductor industries (micro-conductive ceramics).

[0024] In the present invention, the bending strength of the environmentally friendly silicon wafer is preferably 8-12 MPa, specifically 8, 9.5 or 12 MPa, which meets the application requirements, and the molding effect is not easy to break when picked up.

[0025] The present invention also provides a method for preparing the environmentally friendly silicon wafer described in the above technical solution, comprising the following steps: mixing silicon powder, a binder, petroleum coke and water to obtain a slurry; drying the slurry to obtain a powder; The powder is formed to obtain the environmentally friendly silicon wafer.

[0026] The present invention mixes silicon powder, a binder, petroleum coke and water to obtain slurry.

[0027] In the present invention, the solid content of the slurry is preferably 40-50 wt%, specifically 40 wt%, 45 wt% or 50 wt%.

[0028] In the present invention, the silicon powder, binder and petroleum coke are preferably poured into a mixing device and stirred evenly, and then water is added to perform ball milling to obtain the slurry.

[0029] In the present invention, the ball milling is preferably a horizontal drum ball mill or a sand mill ball mill, and the ball milling time is preferably 6 to 12 hours, specifically 6, 8, 10 or 12 hours.

[0030] After obtaining the slurry, the present invention dries the slurry to obtain powder.

[0031] In the present invention, the drying is preferably spray drying or direct drying. The inlet temperature of the spray drying is preferably 150-180°C, specifically 150, 160, 170 or 180°C, and the outlet temperature is preferably 50-80°C, specifically 50, 60, 70 or 80°C. The temperature of the direct drying is preferably 60-80°C, specifically 60, 70 or 80°C. The present invention has no special limitation on the drying time, as long as it can ensure the complete removal of water.

[0032] After obtaining the powder, the present invention shapes the powder to obtain the environmentally friendly silicon wafer.

[0033] In the present invention, the molding pressure is preferably 15-40 MPa, specifically 15, 20, 25, 30, 35 or 40 MPa, and the molding is preferably dry pressing.

[0034] The present invention also provides the use of the environmentally friendly silicon wafer described in the above technical solution or the environmentally friendly silicon wafer prepared by the preparation method described in the above technical solution in the field of reaction-sintered silicon carbide ceramics.

[0035] The present invention has no particular limitation on the specific manner of the application, and any manner familiar to those skilled in the art may be used.

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1 100 kg of silicon powder (100 mesh), 5 kg of corn starch, and 10 kg of petroleum coke were poured into a mixing apparatus and stirred thoroughly. Deionized water was then added to form a slurry with a solid content of 45 wt%. The slurry was then subjected to a horizontal drum ball mill for 10 hours. The slurry was then spray-dried to a powder with an inlet temperature of 160°C and an outlet temperature of 70°C. The powder was dry-pressed to form an environmentally friendly silicon wafer at a pressure of 15 MPa. The resulting environmentally friendly silicon wafer had a flexural strength of 8 MPa, meeting application requirements. No unpleasant odor was observed during wafer preparation and siliconization sintering. Furthermore, the resulting environmentally friendly silicon wafer maintained a round shape after sintering and silicon dissolution, even after a portion of the carbon content (solid content) was converted during siliconization sintering. This ensured that the wafer remained round and had no deformation after sintering and silicon dissolution, avoiding the problem of large deformation of the binder after sintering and becoming inseparable from the sintered silicon carbide ceramic.

[0038] Example 2 100 kg of silicon powder (100 mesh), 6.8 kg of maltose, and 10 kg of petroleum coke were placed in a mixing apparatus and stirred thoroughly. Deionized water was then added to form a slurry with a solids content of 45 wt%. The slurry was then ball-milled in a horizontal drum for 12 hours. The slurry was spray-dried to a powder with an inlet temperature of 170°C and an outlet temperature of 60°C. The powder was dry-pressed to form an environmentally friendly silicon wafer at a pressure of 30 MPa. The resulting environmentally friendly silicon wafer exhibited a flexural strength of 9.5 MPa and exhibited no unpleasant odor during wafer preparation and siliconization sintering, meeting application requirements. Furthermore, the resulting environmentally friendly silicon wafer ensured that even after a portion of the carbon content (solids content) was converted during siliconization sintering, the wafer retained a round shape and exhibited no deformation after sintering and silicon dissolution. This avoided the problem of large deformation of the binder after sintering, which could result in inseparability from the sintered silicon carbide ceramic.

[0039] Example 3 100 kg of silicon powder (100 mesh), 10 kg of corn starch, and 10 kg of petroleum coke were poured into a mixing apparatus and stirred evenly. Deionized water was then added to form a slurry with a solid content of 40 wt%. The slurry was subjected to a horizontal drum ball mill for 8 hours. The slurry was spray-dried to a powder with an inlet temperature of 180°C and an outlet temperature of 80°C. The powder was dry-pressed to form an environmentally friendly silicon wafer at a pressure of 20 MPa. The resulting environmentally friendly silicon wafer exhibited a flexural strength of 12 MPa and exhibited no unpleasant odor during wafer preparation and siliconization sintering, meeting application requirements. Furthermore, the resulting environmentally friendly silicon wafer ensured that even after converting a portion of the carbon content (solid content) during siliconization sintering, the wafer retained a round shape and exhibited no deformation after sintering and silicon dissolution. This avoided the problem of large deformation of the binder after sintering and the inability to separate from the sintered silicon carbide ceramic.

[0040] Comparative Example 1 100 kg of silicon powder (containing boron nitride), 10 kg of phenolic resin, and 10 kg of boron nitride were poured into a mixing apparatus and stirred thoroughly. Alcohol was then added as a solvent to form a slurry with a solid content of 40 wt%. The slurry was then subjected to a horizontal drum ball mill for 8 hours. The slurry was spray-dried to a powder with an inlet temperature of 180°C and an outlet temperature of 80°C. The powder was dry-pressed to form silicon wafers at a pressure of 20 MPa. The resulting wafers had a flexural strength of 15 MPa. However, an unpleasant odor was observed during the spray drying and siliconization sintering processes, which did not meet environmental requirements. Furthermore, the presence of boron nitride in the silicon powder could easily lead to boron contamination of silicon carbide ceramic products, making it unsuitable for use in certain semiconductor applications (such as micro-conductive ceramics).

[0041] Comparative Example 2 100 kg of silicon powder (100 mesh), 12 kg of corn starch, and 10 kg of petroleum coke were poured into a mixing device and stirred evenly. Deionized water was then added to form a slurry with a solid content of 45 wt%. The slurry was subjected to a horizontal drum ball mill with a mixing time of 10 hours. The slurry was spray dried to obtain a powder, wherein the spray drying inlet temperature was 160°C and the outlet temperature was 70°C. The powder was dry-pressed to obtain an environmentally friendly silicon wafer at a molding pressure of 15 MPa. The resulting environmentally friendly silicon wafer had a flexural strength of 12 MPa, meeting the application requirements. There was no unpleasant odor during silicon wafer preparation and siliconization sintering. However, the carbon content of the obtained environmentally friendly silicon wafer was converted during siliconization sintering to a level that caused the appearance of the blank to be deformed after sintering and silicon dissolution, and it could not be separated from the silicon carbide ceramic to be sintered.

[0042] Comparative Example 3 100 kg of silicon powder (100 mesh), 4 kg of corn starch, and 10 kg of petroleum coke were poured into a mixing device and stirred evenly. Deionized water was then added to form a slurry with a solid content of 45 wt%. The slurry was subjected to a horizontal drum ball mill with a mixing time of 10 h. The slurry was spray dried to obtain a powder, wherein the spray drying inlet temperature was 160°C and the outlet temperature was 70°C. The powder was dry-pressed to obtain an environmentally friendly silicon wafer at a molding pressure of 15 MPa. The obtained environmentally friendly silicon wafer had a flexural strength of 10 MPa, which met the application requirements. There was no unpleasant odor during silicon wafer preparation and siliconization sintering. However, the obtained environmentally friendly silicon wafer converted its carbon content during siliconization sintering to a point where the appearance of the blank was deformed after sintering and silicon dissolution, and it could not be separated from the silicon carbide ceramic to be sintered.

[0043] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. An environmentally friendly silicon wafer, characterized in that: The invention is prepared from the following raw materials in parts by weight: 100 parts of silicon powder, 5-10 parts of a binder, 8-15 parts of petroleum coke and water. The binder is an environmentally friendly binder and includes one or more of corn starch, maltose, sucrose and glucose.

2. The environmentally friendly silicon wafer according to claim 1, characterized in that: The environmentally friendly silicon is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 5 to 10 parts of a binder, 10 parts of petroleum coke and water.

3. The environmentally friendly silicon wafer according to claim 2, characterized in that: The environmentally friendly silicon is prepared from the following raw materials in parts by mass: 100 parts of silicon powder, 6.8 parts of a binder, 10 parts of petroleum coke and water.

4. The environmentally friendly silicon wafer according to any one of claims 1 to 3, characterized in that: The particle size of the silicon powder is 80-300 mesh.

5. The environmentally friendly silicon wafer according to claim 4, characterized in that: The particle size of the silicon powder is 100-200 mesh.

6. The method for preparing an environmentally friendly silicon wafer according to any one of claims 1 to 5, characterized in that: The following steps are involved: mixing silicon powder, a binder, petroleum coke and water to obtain a slurry; drying the slurry to obtain a powder; The powder is formed to obtain the environmentally friendly silicon wafer.

7. The preparation method according to claim 6, characterized in that The solid content of the slurry is 40-50 wt %.

8. The preparation method according to claim 6, characterized in that The drying is spray drying or direct drying. The inlet temperature of the spray drying is 150-180°C and the outlet temperature is 50-80°C. The temperature of the direct drying is 60-80°C.

9. The preparation method according to claim 6, characterized in that The molding pressure is 15-40 MPa.

10. Use of the environmentally friendly silicon wafer according to any one of claims 1 to 5 or the environmentally friendly silicon wafer prepared by the preparation method according to any one of claims 6 to 9 in the field of reaction-bonded silicon carbide ceramics.