Silicon nitride ceramic tile and surface treatment process thereof

Abstract

The present invention relates to the field of semiconductor surface treatment technology, specifically to a silicon nitride ceramic piece and a surface treatment process thereof. The method comprises the following steps: step 1: sintering a silicon nitride ceramic body to obtain a silicon nitride ceramic; step 2: subjecting the silicon nitride ceramic to laser pretreatment and double-sided grinding in sequence to obtain a pretreated silicon nitride ceramic piece; step 3: immersing the pretreated silicon nitride ceramic piece in an acid etching solution for acid etching to obtain a silicon nitride ceramic piece A; step 4: cleaning the silicon nitride ceramic piece A once to obtain a silicon nitride ceramic piece B; step 5: cleaning the silicon nitride ceramic piece B twice to obtain a silicon nitride ceramic piece C; step 6: coating the surface of the silicon nitride ceramic piece C with a layer of silicon carbide modified film; thereby obtaining a silicon nitride ceramic piece.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor surface treatment, in particular to a silicon nitride ceramic piece and a surface treatment process thereof. Background Art

[0002] With the continuous development of science and technology, silicon nitride ceramics, as a high-performance ceramic material with high strength and high insulation, are widely used in the semiconductor industry.

[0003] Surface defects of silicon nitride ceramic tiles can have a great impact on the performance of the tiles, including appearance, thermal conductivity, dielectric strength and voltage resistance. At present, the internal toughness of silicon nitride ceramic tiles is low, and stress causes surface defects such as cracks in the surface treatment. In addition, surface treatment generally uses sandblasting or double-sided grinding to process the surface of the tile to reduce the presence of surface defects, but sandblasting has a general ability to handle bumps and pits; although the double-sided grinding process has a strong ability to handle bumps and pits, the processing time is extremely long and the time cost is high. In addition, the coating on the silicon nitride surface has problems such as poor interface performance and high stress, which greatly affects the performance of silicon nitride tiles.

[0004] In summary, it is of great significance to solve the above problems and form a surface treatment process for silicon nitride ceramic sheets. Summary of the Invention

[0005] The purpose of the present invention is to provide a silicon nitride ceramic sheet and a surface treatment process thereof to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A surface treatment process for a silicon nitride ceramic tile comprises the following steps:

[0008] Step 1: Sintering the silicon nitride ceramic body to obtain silicon nitride ceramic;

[0009] Step 2: performing laser pretreatment and double-side grinding on the silicon nitride ceramic in sequence to obtain a pretreated silicon nitride ceramic piece;

[0010] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution for acid etching to obtain a silicon nitride ceramic piece A;

[0011] Step 4: Clean the silicon nitride ceramic piece A to obtain the silicon nitride ceramic piece B;

[0012] Step 5: Clean the silicon nitride ceramic piece B twice to obtain the silicon nitride ceramic piece C;

[0013] Step 6: A layer of silicon carbide modified film is plated on the surface of the silicon nitride ceramic piece C to obtain a silicon nitride ceramic piece.

[0014] More optimally, in step 1, the specific steps are: α-silicon nitride, modified titanium nitride, and sintering aid are added to a solvent in sequence, ball-milled, dried, and ground, and rolled at 150-180 MPa to obtain a silicon nitride ceramic body; the temperature is raised to 200-250°C at a rate of 5°C / min in a nitrogen atmosphere, and kept warm for 30-40 minutes; the temperature is raised to 750-800°C at a rate of 5°C / min, and kept warm for 10-15 minutes; the temperature is raised to 1600-1650°C at a rate of 2°C / min, and kept warm for 1-1.5 hours; the nitrogen pressure is set to 2-4 MPa, and the heat preservation is continued for 1-1.5 hours; after reducing the pressure, the temperature is lowered to 800°C at a rate of 2°C / min, and cooled with the furnace to obtain silicon nitride ceramics.

[0015] More optimally, in step 1, the raw materials of the silicon nitride ceramic include: 100 parts of α-silicon nitride, 12 to 15 parts of modified titanium nitride, and 8 to 10 parts of sintering aids; the sintering aids include magnesium fluoride and yttrium oxide in a mass ratio of 0.8 to 1.2:0.8 to 1.2.

[0016] More optimally, the preparation method of the modified titanium nitride is:

[0017] S1-1: Add vinylferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.3-3.4 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2-4 hours, and remove the solvent by distillation under reduced pressure to obtain a ferrocene-based coupling agent;

[0018] S1-2: Add 1 to 2 parts of titanium nitride by weight to an 80 to 85 wt% ethanol aqueous solution to obtain a 0.1 to 0.2 g / mL dispersion; add 2.5 to 5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 800 to 2000 r / min, add 0.5 to 1 part of a ferrocene-based coupling agent, stir for 4 to 5 hours, centrifuge, and dry to obtain modified titanium nitride.

[0019] In order to reduce surface defects during subsequent surface treatment of silicon nitride ceramics, the raw materials and sintering process of silicon nitride ceramics are restricted to effectively improve their fracture toughness, reduce the stress of subsequent surface treatment, and reduce surface defects. Among them, by introducing titanium nitride as a toughening agent and compounding it with alumina sol, alumina is used to effectively improve the dispersion of titanium nitride in the ceramic and the sintering fluidity, thereby improving performance. At the same time, the introduction of titanium nitride can effectively promote the formation of β-Si3N4 and improve fracture toughness. At the same time, the alumina in the introduced alumina sol can synergistically promote sintering with the sintering aid. The introduced iron can be doped with alumina within the silicon nitride lattice during the sintering process, effectively promoting the formation of β-Si3N4 and improving performance. In addition, strict temperature control procedures during sintering and the setting of intermediate nitrogen pressure can effectively improve density, inhibit adverse interfacial reactions, and thus improve strength. It should be noted that the amount of modified titanium nitride introduced needs to be controlled. If too little is introduced, the strength increase is limited. If too much is introduced, segregation will occur, which will reduce the fracture toughness.

[0020] More optimally, in step 2, the preparation process is: setting the optical fiber output to 290-310W, the minimum spot diameter to 0.5-0.7mm, the laser wavelength to 1.05-1.07μm, the laser incident angle to 45-60°, the laser spot diameter to 3.5-4mm, and performing laser pretreatment operation on silicon nitride ceramics at a cutting speed of 59-59.5m / min, laser preheating for 18-22s, and a milling cutter distance from the center of the laser spot of 3-3.5mm, and then setting the grinding number to 500-1000 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0021] More optimally, in step 3, the preparation process is: immersing the pretreated silicon nitride ceramic piece in an acid etching solution, and performing acid etching treatment at 50-80° C. for 20-60 minutes to obtain silicon nitride ceramic piece A.

[0022] More optimally, in step 3, the acid etching solution is prepared by mixing 95-98 wt% phosphoric acid, 95-98 wt% sulfuric acid, ammonium dihydrogen phosphate and deionized water in a mass ratio of 80-85:2-3:2-8:5-12.

[0023] More optimally, in step 4, the preparation process for one cleaning is as follows: setting the dry ice particle size to 1-3 mm, the cleaning angle to 20-30°, the cleaning distance to 10-20 cm, and the cleaning pressure to 3×10 5 ~5×10 5 The silicon nitride ceramic piece A is cleaned once for 10 to 20 minutes at Pa to obtain the silicon nitride ceramic piece B.

[0024] In a further solution, a dry ice jet cleaning technology is used for one cleaning, which is a physical cleaning.

[0025] More optimally, in step 5, the preparation process for the secondary cleaning is: in a mixed atmosphere of hydrogen and argon with a mass ratio of 0.8-1:0.8-1, the RF power is set to 40-60W, and the pressure is 3-13Pa to perform secondary cleaning on the silicon nitride ceramic piece B for 20-40 minutes to obtain the silicon nitride ceramic piece C.

[0026] In a further solution, the secondary cleaning adopts plasma cleaning technology, which is chemical cleaning.

[0027] In the plan, laser pretreatment is used to reduce double-sided grinding time and improve production efficiency; subsequently, acid etching, primary cleaning, secondary cleaning, and coating are used to clean surface impurities caused by laser treatment, further reduce the roughness of silicon nitride ceramics, and solve problems such as large coating stress and poor interface performance, thereby synergistically enhancing the thermal conductivity, wear resistance, and mechanical properties of silicon nitride ceramics.

[0028] Among them, silicon carbide has high wear resistance, high thermal conductivity, and high mechanical properties. This solution uses a Hall ion source to assist in the preparation of silicon carbide thin films to enhance the thermal conductivity, wear resistance, and mechanical properties of silicon nitride ceramics. However, the Hall ion source-assisted preparation of silicon carbide thin films is also accompanied by the problem of high stress, which can cause the silicon nitride ceramics to break before coating. In addition, there is also the problem of poor interface performance between silicon nitride ceramics and silicon carbide, which can cause subsequent peeling of the film, greatly affecting the performance of the silicon nitride ceramics.

[0029] Therefore, acid etching treatment is used to refine the laser treatment and remove some residues and micro defects on the surface of the silicon nitride ceramic tile, which is beneficial to the subsequent preparation of thin films.

[0030] More importantly, the solution also adopts a combination of primary cleaning (physical) and secondary cleaning (chemical) to remove physical and chemical pollutants on the surface after laser etching, respectively, synergistically reduce the surface roughness of silicon nitride ceramics, enhance the surface activity of silicon nitride ceramics, increase the chemical interface properties of the subsequent surface coating of a layer of silicon carbide modified film, and enhance the interface bonding strength. At the same time, it can also alleviate the residual stress on the surface of the silicon nitride ceramics, provide a low-stress substrate for subsequent silicon carbide film deposition, and reduce the risk of film falling off.

[0031] More optimally, in step 6, the preparation process is: silicon nitride ceramic piece C is placed in a vacuum of 7.5×10 -4 ~8.5×10 -4 Pa is heated to 200-300°C and kept warm for 1-2 hours, silicon is evaporated under a pressure of 5-8kV, and then argon and methane gases are introduced to form surface bonding. After polishing, silicon nitride ceramic pieces are obtained.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. In the plan, in order to reduce the surface defects of silicon nitride ceramics during subsequent surface treatment, the raw materials and sintering process of silicon nitride ceramics are limited to effectively improve their fracture toughness, reduce the stress of subsequent surface treatment, and reduce surface defects; the plan adopts laser pretreatment to reduce double-sided grinding time and improve production efficiency; subsequently, acid etching, one-time cleaning, two-time cleaning, and coating are used to clean surface impurities after laser treatment, further reduce the roughness of silicon nitride ceramics, and solve problems such as large coating stress and poor interface performance, synergistically enhancing the thermal conductivity, wear resistance, and mechanical properties of silicon nitride ceramics.

[0034] 2. The solution uses laser pretreatment to improve the surface quality of silicon nitride ceramic tiles, reduce the subsequent double-sided grinding time, and improve production efficiency. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] It should be noted that the following parts are by mass, and all raw materials involved in the present invention are purchased from manufacturers without any special restrictions. Examples include: In the following examples, all materials are commercially purchased.

[0037] Example 1: A surface treatment process for a silicon nitride ceramic tile, comprising the following steps:

[0038] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 13.5 parts of modified Titanium nitride and 9 parts of sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The product is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The product is heated to 225°C at a rate of 5°C / min and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the product is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0039] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0040] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0041] Step 4: Set the dry ice particle size to 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4 × 10 5 The silicon nitride ceramic piece A was cleaned once for 15 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0042] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 50 W and the pressure was 8 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 30 minutes to obtain a silicon nitride ceramic piece C;

[0043] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10-4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramics were obtained.

[0044] Example 2: A surface treatment process for a silicon nitride ceramic tile, comprising the following steps:

[0045] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.3 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1 part of titanium nitride to 80wt% ethanol aqueous solution by weight to obtain a 0.1g / mL dispersion; add 2.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 800r / min, add 0.5 parts of ferrocene-based coupling agent, stir for 4 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride and 12 parts of modified nitrogen Titanium dioxide and 8 parts of a sintering aid are sequentially added to a solvent and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The mixture is dried and ground, and rolled at 150 MPa to obtain a silicon nitride ceramic body. The body is heated to 200°C at a rate of 5°C / min under a nitrogen atmosphere and kept warm for 30 minutes; heated to 750°C at a rate of 5°C / min and kept warm for 10 minutes; heated to 1600°C at a rate of 2°C / min and kept warm for 1 hour; the nitrogen pressure is set to 2 MPa and kept warm for 1 hour; after depressurization, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0046] Step 2: Set the fiber output to 290W, the minimum spot diameter to 0.5mm, the laser wavelength to 1.05μm, the laser incident angle to 45°, the laser spot diameter to 3.5mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59m / min, laser preheating for 18s, and a distance of 3mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 500 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0047] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 80:2:2:5 of 95 wt% phosphoric acid, 95 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 50° C. for 20 minutes to obtain silicon nitride ceramic piece A;

[0048] Step 4: Set the dry ice particle size to 1mm, the cleaning angle to 20°, the cleaning distance to 10cm, and the cleaning pressure to 4×10 5 The silicon nitride ceramic piece A was cleaned once for 10 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0049] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 40 W and the pressure was 3 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 20 minutes to obtain a silicon nitride ceramic piece C;

[0050] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10 -4 Pa was heated to 200°C and kept warm for 1 hour, silicon was evaporated under a pressure of 5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramic wafers were obtained.

[0051] Example 3: A surface treatment process for a silicon nitride ceramic tile, comprising the following steps:

[0052] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:3.4 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 2 parts of titanium nitride to 85wt% ethanol aqueous solution by weight to obtain a 0.2g / mL dispersion; add 5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 2000r / min, add 1 part of ferrocene-based coupling agent, stir for 5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 15 parts of modified titanium nitride, 1 0 parts of sintering aid are sequentially added to the solvent and ball-milled and mixed, the sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1, dried and ground, and rolled at 180 MPa to obtain a silicon nitride ceramic body; the body is heated to 250°C at a rate of 5°C / min under a nitrogen atmosphere and kept warm for 40 minutes; heated to 800°C at a rate of 5°C / min and kept warm for 15 minutes; heated to 1650°C at a rate of 2°C / min and kept warm for 1.5 hours; the nitrogen pressure is set to 4 MPa and kept warm for 1.5 hours; after depressurization, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic;

[0053] Step 2: Set the fiber output to 310W, the minimum spot diameter to 0.7mm, the laser wavelength to 1.07μm, the laser incident angle to 60°, the laser spot diameter to 4mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.5m / min, laser preheating for 22s, and a distance of 3.5mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 1000 mesh and perform double-sided grinding to obtain pretreated silicon nitride ceramics.

[0054] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution, wherein the etching solution is prepared according to a mass ratio of 85:3:8:12, which is 98wt% phosphoric acid, 98wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 80°C for 60 minutes to obtain silicon nitride ceramic piece A;

[0055] Step 4: Set the dry ice particle size to 3mm, the cleaning angle to 30°, the cleaning distance to 20cm, and the cleaning pressure to 4×10 5 The silicon nitride ceramic piece A was cleaned once for 20 min at Pa to obtain the silicon nitride ceramic piece B;

[0056] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 60 W and the pressure was 13 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 40 minutes to obtain a silicon nitride ceramic piece C;

[0057] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10 -4 Pa was heated to 300°C and kept warm for 2 hours, silicon was evaporated under a pressure of 8kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramic pieces were obtained.

[0058] Comparative Example 1: Based on Example 1, the sandblasting surface treatment in the prior art was adopted, and the other processes remained unchanged, specifically:

[0059] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 13.5 parts of modified Titanium nitride and 9 parts of sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The product is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The product is heated to 225°C at a rate of 5°C / min and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the product is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0060] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the spray distance to 9cm, the compressed air pressure to 4bar, and sandblast for 20s with 50-mesh aluminum oxide powder as the abrasive to obtain pretreated silicon nitride ceramics.

[0061] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0062] Step 4: Set the dry ice particle size to 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4 × 10 5 The silicon nitride ceramic piece A was cleaned once for 15 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0063] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 50 W and the pressure was 8 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 30 minutes to obtain a silicon nitride ceramic piece C;

[0064] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10 -4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramics were obtained.

[0065] Comparative Example 2: Based on Example 1, the cleaning method in the prior art was adopted, and the other processes remained unchanged, specifically:

[0066] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 13.5 parts of modified Titanium nitride and 9 parts of sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The product is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The product is heated to 225°C at a rate of 5°C / min and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the product is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0067] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0068] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0069] Step 4: Using deionized water, ethanol, and petroleum ether in sequence, the silicon nitride ceramic piece A was ultrasonically cleaned for 10 minutes at an ultrasonic frequency of 25 kHz and a power of 500 W to obtain a silicon nitride ceramic piece B;

[0070] Step 5: Place silicon nitride ceramic tile B in a vacuum of 8×10 -4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramic wafers were obtained.

[0071] Comparative Example 3: Based on Example 1, only one cleaning process is used, and the rest of the process remains unchanged, specifically:

[0072] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 13.5 parts of modified Titanium nitride and 9 parts of sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The product is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The product is heated to 225°C at a rate of 5°C / min and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the product is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0073] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0074] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0075] Step 4: Set the dry ice particle size to 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4 × 10 5 The silicon nitride ceramic piece A was cleaned once for 15 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0076] Step 5: Place silicon nitride ceramic tile B in a vacuum of 8×10 -4Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramics were obtained.

[0077] Comparative Example 4: Based on Example 1, acid etching was not used, and the other processes remained unchanged, specifically:

[0078] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride, 13.5 parts of modified Titanium nitride and 9 parts of sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The product is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The product is heated to 225°C at a rate of 5°C / min and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the product is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0079] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0080] Step 3: Set the dry ice particle size to 2mm, the cleaning angle to 25°, the cleaning distance to 15cm, and the cleaning pressure to 4×10 5 The pretreated silicon nitride ceramic was cleaned once for 15 min at 400 Pa to obtain silicon nitride ceramic piece A;

[0081] Step 4: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 50 W and the pressure was 8 Pa to perform a secondary cleaning on the silicon nitride ceramic wafer A for 30 minutes to obtain a silicon nitride ceramic wafer B;

[0082] Step 5: Place silicon nitride ceramic tile B in a vacuum of 8×10 -4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramics were obtained.

[0083] Comparative Example 5: Based on Example 1, the modified titanium nitride content is too high, and the other processes remain unchanged, specifically:

[0084] Step 1: S1: Add vinyl ferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.8 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2 to 4 hours, and remove the solvent by reduced pressure distillation to obtain a ferrocene-based coupling agent; add 1.5 parts of titanium nitride to 82wt% ethanol aqueous solution by weight to obtain a 0.15g / mL dispersion; add 3.5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 1400r / min, add 0.8 parts of ferrocene-based coupling agent, stir for 4.5 hours, centrifuge and dry to obtain modified titanium nitride; S2: Add 100 parts of α-silicon nitride and 22 parts of modified Titanium nitride and 9 parts of a sintering aid are sequentially added to a solvent and ball-milled, wherein the sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The mixture is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The body is heated to 225°C at a rate of 5°C / min under a nitrogen atmosphere and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0085] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0086] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0087] Step 4: Set the dry ice particle size to 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4 × 10 5The silicon nitride ceramic piece A was cleaned once for 15 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0088] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 50 W and the pressure was 8 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 30 minutes to obtain a silicon nitride ceramic piece C;

[0089] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10 -4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramics were obtained.

[0090] Comparative Example 6: Based on Example 1, the modified titanium nitride was replaced with titanium nitride, and the other processes remained unchanged, specifically:

[0091] Step 1: 100 parts of α-silicon nitride, 13.5 parts of titanium nitride, and 9 parts of a sintering aid are added to a solvent in sequence and ball-milled and mixed. The sintering aid includes magnesium fluoride and yttrium trioxide in a ratio of 1:1. The mixture is dried and ground, and rolled at 165 MPa to obtain a silicon nitride ceramic body. The body is heated to 225°C at a rate of 5°C / min under a nitrogen atmosphere and kept warm for 35 minutes; heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; heated to 1625°C at a rate of 2°C / min and kept warm for 1.2 hours; the nitrogen pressure is set to 3 MPa and kept warm for 1.2 hours; after depressurization, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic body.

[0092] Step 2: Set the fiber output to 300W, the minimum spot diameter to 0.6mm, the laser wavelength to 1.06μm, the laser incident angle to 53°, the laser spot diameter to 3.8mm, and perform laser pretreatment on the silicon nitride ceramic at a cutting speed of 59.2m / min, laser preheating for 20s, and a distance of 3.2mm between the milling cutter and the center of the laser spot. Then, set the grinding number to 750 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

[0093] Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution prepared by a mass ratio of 82.5:2.5:5:8 of 97 wt% phosphoric acid, 96 wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 65° C. for 40 minutes to obtain silicon nitride ceramic piece A;

[0094] Step 4: Set the dry ice particle size to 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4 × 10 5 The silicon nitride ceramic piece A was cleaned once for 15 min at 400 Pa to obtain the silicon nitride ceramic piece B;

[0095] Step 5: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the RF power was set to 50 W and the pressure was 8 Pa to perform a secondary cleaning on the silicon nitride ceramic piece B for 30 minutes to obtain a silicon nitride ceramic piece C;

[0096] Step 6: Place the silicon nitride ceramic piece C in a vacuum of 8×10 -4 Pa was heated to 250°C and kept warm for 1.5 hours, silicon was evaporated under a pressure of 6.5kV, and then argon and methane gases were introduced to form surface bonding. After polishing, silicon nitride ceramic wafers were obtained.

[0097] Testing experiment: The performance of a silicon nitride ceramic sheet prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was tested: (1) Fracture toughness test: The mechanical properties of a silicon nitride ceramic sheet prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were measured with reference to the standard "GB / T 23806-2009 Test method for fracture toughness of fine ceramics - single-side pre-cracked beam method", and the results are shown in Table 1; (2) Thermal conductivity test: The thermal conductivity of a silicon nitride ceramic sheet prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was tested with reference to the test method for thermal conductivity of high thermal conductivity ceramics in "GB / T 39862-2021", and the results are shown in Table 1;

[0098]

[0099] Table 1

[0100] Result analysis: According to the data analysis in Table 1, it can be seen that in the scheme, in order to reduce the surface defects of silicon nitride ceramics during subsequent surface treatment, the raw materials and sintering process of silicon nitride ceramics are limited to effectively improve their fracture toughness, reduce the stress of subsequent surface treatment, and reduce surface defects; the scheme adopts laser pretreatment to reduce double-sided grinding time and improve production efficiency; subsequently, acid etching, primary cleaning, secondary cleaning, and coating are used to clean surface impurities after laser treatment, further reduce the roughness of silicon nitride ceramics, and solve problems such as large coating stress and poor interface performance, synergistically enhancing the thermal conductivity, wear resistance, and mechanical properties of silicon nitride ceramics.

[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A surface treatment process for silicon nitride ceramics, characterized in that: The following steps are involved: Step 1: Sintering the silicon nitride ceramic body to obtain silicon nitride ceramic; Step 2: performing laser pretreatment and double-side grinding on the silicon nitride ceramic in sequence to obtain a pretreated silicon nitride ceramic piece; Step 3: Immerse the pretreated silicon nitride ceramic piece in an acid etching solution for acid etching to obtain a silicon nitride ceramic piece A; Step 4: Clean the silicon nitride ceramic piece A to obtain the silicon nitride ceramic piece B; Step 5: Clean the silicon nitride ceramic piece B twice to obtain the silicon nitride ceramic piece C; Step 6: Coating a layer of silicon carbide modified film on the surface of the silicon nitride ceramic piece C to obtain a silicon nitride ceramic piece; The raw materials of the silicon nitride ceramic include: 100 parts of α-silicon nitride, 12 to 15 parts of modified titanium nitride, and 8 to 10 parts of a sintering aid; the sintering aid includes magnesium fluoride and yttrium trioxide in a mass ratio of 0.8 to 1.2:0.8 to 1.2; The preparation method of the modified titanium nitride is: S1-1: Add vinylferrocene and mercaptosilane coupling agent in a mass ratio of 2.1:2.3-3.4 to tetrahydrofuran, add azobisisobutyronitrile, stir under ultraviolet light for 2-4 hours, and remove the solvent by distillation under reduced pressure to obtain a ferrocene-based coupling agent; S1-2: Add 1 to 2 parts of titanium nitride by weight to an 80 to 85 wt% ethanol aqueous solution to obtain a 0.1 to 0.2 g / mL dispersion; add 2.5 to 5 parts of nano-alumina sol and ultrasonically disperse; stir evenly at 800 to 2000 r / min, add 0.5 to 1 part of a ferrocene-based coupling agent, stir for 4 to 5 hours, centrifuge, and dry to obtain modified titanium nitride.

2. The surface treatment process of a silicon nitride ceramic tile according to claim 1, characterized in that: In step 1, the specific steps are: adding α-silicon nitride, modified titanium nitride, and a sintering aid to a solvent in sequence, ball milling and mixing, drying, grinding, and rolling it at 150-180 MPa to obtain a silicon nitride ceramic body; heating it to 200-250°C at a rate of 5°C / min in a nitrogen atmosphere, and keeping it warm for 30-40 minutes; heating it to 750-800°C at a rate of 5°C / min, and keeping it warm for 10-15 minutes; heating it to 1600-1650°C at a rate of 2°C / min, and keeping it warm for 1-1.5 hours; setting the nitrogen pressure to 2-4 MPa, and continuing to keep it warm for 1-1.5 hours; after reducing the pressure, cooling it to 800°C at a rate of 2°C / min, cooling it with the furnace, and obtaining silicon nitride ceramics.

3. The surface treatment process of a silicon nitride ceramic tile according to claim 1, characterized in that: In step 2, the preparation process is as follows: setting the optical fiber output to 290-310W, the minimum spot diameter to 0.5-0.7mm, the laser wavelength to 1.05-1.07μm, the laser incident angle to 45-60°, the laser spot diameter to 3.5-4mm, and performing laser pretreatment operation on silicon nitride ceramics at a cutting speed of 59-59.5m / min, laser preheating for 18-22s, and a milling cutter distance from the center of the laser spot of 3-3.5mm, and then setting the grinding number to 500-1000 meshes for double-sided grinding operation to obtain pretreated silicon nitride ceramics.

4. The surface treatment process of a silicon nitride ceramic tile according to claim 1, characterized in that: In step 3, the preparation process is as follows: immersing the pretreated silicon nitride ceramic piece in an acid etching solution, and performing acid etching treatment at 50 to 80° C. for 20 to 60 minutes to obtain a silicon nitride ceramic piece A.

5. The surface treatment process of a silicon nitride ceramic tile according to claim 4, characterized in that: In step 3, the acid etching solution is prepared by mixing 95-98 wt% phosphoric acid, 95-98 wt% sulfuric acid, ammonium dihydrogen phosphate and deionized water in a mass ratio of 80-85:2-3:2-8:5-12.

6. The surface treatment process of a silicon nitride ceramic tile according to claim 1, characterized in that: In step 4, the preparation process of the one-time cleaning is as follows: setting the dry ice particle size to 1-3 mm, the cleaning angle to 20-30°, the cleaning distance to 10-20 cm, and the cleaning pressure to 3×10 5 ~5×10 5 The silicon nitride ceramic piece A is cleaned once for 10 to 20 minutes at Pa to obtain the silicon nitride ceramic piece B.

7. The surface treatment process of a silicon nitride ceramic tile according to claim 1, characterized in that: In step 5, the preparation process of the secondary cleaning is: in a mixed atmosphere of hydrogen and argon with a mass ratio of 0.8-1:0.8-1, the RF power is set to 40-60W, and the pressure is 3-13Pa to perform secondary cleaning on the silicon nitride ceramic piece B for 20-40 minutes to obtain the silicon nitride ceramic piece C.

8. The surface treatment process for a silicon nitride ceramic tile according to claim 1, characterized in that: In step 6, the preparation process is as follows: the silicon nitride ceramic piece C is placed in a vacuum of 7.5×10-4~8.5×10-4Pa at a temperature of 200~300℃ and kept warm for 1~2 hours, silicon is evaporated at a pressure of 5~8kV, and then argon and methane gases are introduced to form surface bonding, and after polishing, a silicon nitride ceramic piece is obtained.

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