Silicon nitride ceramic chip and surface treatment process thereof

Abstract

The invention relates to the technical field of semiconductor surface treatment, in particular to a silicon nitride ceramic chip and a surface treatment process thereof. Comprising the following steps: step 1, sintering a silicon nitride ceramic green body to obtain silicon nitride ceramic; 2, sequentially carrying out laser pretreatment and double-sided grinding on the silicon nitride ceramic to obtain a pretreated silicon nitride ceramic chip; 3, immersing the pretreated silicon nitride ceramic chip into an acid etching solution, and carrying out acid etching treatment to obtain a silicon nitride ceramic chip A; 4, cleaning the silicon nitride ceramic chip A for the first time to obtain a silicon nitride ceramic chip B; step 5, carrying out secondary cleaning on the silicon nitride ceramic chip B to obtain a silicon nitride ceramic chip C; 6, plating a layer of silicon carbide modified film on the surface of the silicon nitride ceramic chip C; therefore, the silicon nitride ceramic chip is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor surface treatment, in particular to a silicon nitride ceramic sheet 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 ceramics will have a great impact on the performance of the ceramics, including appearance, thermal conductivity, dielectric strength and voltage resistance. At present, the internal toughness of silicon nitride ceramics 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 ceramic to reduce the existence of surface defects, but sandblasting has average processing capabilities for protrusions and pits; although the double-sided grinding process has a strong processing capability for protrusions and pits, the processing time is extremely long and the time cost is high. In addition, there are problems such as poor interface performance and high stress on the surface coating of silicon nitride, which greatly affect the performance of silicon nitride ceramics.

[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 sheet comprises the following steps:

[0008] Step 1: sintering a silicon nitride ceramic body to obtain a silicon nitride ceramic;

[0009] Step 2: subjecting the silicon nitride ceramic to laser pretreatment and double-sided grinding processes in sequence to obtain a pretreated silicon nitride ceramic wafer;

[0010] 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;

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

[0012] Step 5: Clean the silicon nitride ceramic piece B for a second time 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: adding α-silicon nitride, modified titanium nitride, and a sintering aid to a solvent in sequence, ball-milling and mixing, drying, and grinding, rolling it at 150-180 MPa to obtain a silicon nitride ceramic embryo; 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.

[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 trioxide 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 vinyl ferrocene 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 reduced pressure distillation to obtain a ferrocene-based coupling agent;

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

[0019] 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 its 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 dispersibility and sintering fluidity of titanium nitride in ceramics and improve 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 promote sintering synergistically with the sintering aid; and the introduced iron can be doped with alumina in 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 interface 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 fracture toughness.

[0020] More optimally, in step 2, the preparation process is: setting the fiber output to 290-310 W, the minimum spot diameter to 0.5-0.7 mm, the laser wavelength to 1.05-1.07 μm, the laser incident angle to 45-60°, the laser spot diameter to 3.5-4 mm, and performing laser pretreatment on silicon nitride ceramics at a cutting speed of 59-59.5 m / min, laser preheating for 18-22 s, and a milling cutter distance of 3-3.5 mm from the center of the laser spot, 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 an acid etching treatment at 50 to 80° C. for 20 to 60 minutes to obtain a silicon nitride ceramic piece A.

[0022] More optimally, in step 3, the acid etching solution is prepared by 95-98wt% phosphoric acid, 95-98wt% 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 the primary 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 gas pressure to 3×10 5 ~5×10 5 The silicon nitride ceramic piece A is cleaned once for 10 to 20 minutes at 400 ℃ and 800 ℃ to obtain the silicon nitride ceramic piece B.

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

[0025] More optimally, in step 5, the secondary cleaning preparation process 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 silicon nitride ceramic piece B is secondary cleaned for 20-40 minutes at a pressure of 3-13Pa to obtain 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 after 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 scheme adopts the method of using 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 method of using a Hall ion source to assist in the 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 microscopic defects on the surface of the silicon nitride ceramic tile, which is beneficial to the subsequent preparation of the thin film.

[0030] More importantly, the scheme 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 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 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 at 200-300°C 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. After polishing, silicon nitride ceramic wafers are obtained.

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

[0033] 1. 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 its 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, so as to synergistically enhance 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 ceramics, reduce the subsequent double-sided grinding time, and improve production efficiency. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part 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 creative work 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, and exemplarily include: In the following examples, materials are commercially purchased.

[0037] Embodiment 1: A surface treatment process of a silicon nitride ceramic sheet comprises 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 the solvent in sequence 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 165Mpa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in 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 3Mpa and kept warm for 1.2 hours; after reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 ℃ 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 is set to 50 W, and the silicon nitride ceramic piece B is secondary cleaned for 30 minutes at a pressure of 8 Pa to obtain a silicon nitride ceramic piece C;

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

[0044] Embodiment 2: A surface treatment process of a silicon nitride ceramic sheet comprises 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 for 2 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 sintering aid are added to the solvent in sequence 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 150Mpa to obtain a silicon nitride ceramic embryo; the embryo is heated to 200°C at a rate of 5°C / min in 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 2Mpa and kept warm for 1 hour; after reducing the pressure, the embryo is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain a silicon nitride ceramic;

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 80:2:2:5, which is 95wt% phosphoric acid, 95wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water, and perform acid etching at 50°C for 20 minutes to obtain a silicon nitride ceramic piece A;

[0048] Step 4: Set the dry ice particle size to 1 mm, the cleaning angle to 20°, the cleaning distance to 10 cm, 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 is set to 40 W, and the silicon nitride ceramic piece B is cleaned for a second time for 20 minutes at a pressure of 3 Pa to obtain a silicon nitride ceramic piece C;

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

[0051] Embodiment 3: A surface treatment process of a silicon nitride ceramic sheet, 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 for 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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, and 1 0 parts of sintering aid are sequentially added into the solvent for ball milling and mixing, 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 embryo; the embryo is heated to 250°C at a rate of 5°C / min in a nitrogen atmosphere, and kept warm for 40 minutes; the embryo is heated to 800°C at a rate of 5°C / min, and kept warm for 15 minutes; the embryo is 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 the temperature is kept warm for 1.5 hours; after reducing the pressure, the embryo 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 silicon nitride ceramics 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 meshes for 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 by 98wt% phosphoric acid, 98wt% sulfuric acid, ammonium dihydrogen phosphate, and deionized water in a mass ratio of 85:3:8:12, 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 3 mm, the cleaning angle to 30°, the cleaning distance to 20 cm, and the cleaning pressure to 4×10 5 The silicon nitride ceramic piece A was cleaned once for 20 min at 400 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 radio frequency power is set to 60 W, and the silicon nitride ceramic piece B is secondary cleaned for 40 minutes at a pressure of 13 Pa to obtain a silicon nitride ceramic piece C;

[0057] Step 6: Place the silicon nitride ceramic chip C in a vacuum of 8×10 -4 Pa is heated to 300°C and kept warm for 2 hours. Silicon is evaporated under a pressure of 8kV and then argon and methane gases are introduced to form surface bonding. After polishing, silicon nitride ceramic wafers are 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 the solvent in sequence 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 165Mpa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in 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 3Mpa and kept warm for 1.2 hours; after reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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 use 50-mesh aluminum oxide powder as an abrasive for sandblasting for 20s to obtain pretreated silicon nitride ceramics;

[0061] 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 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 ℃ 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 is set to 50 W, and the silicon nitride ceramic piece B is secondary cleaned for 30 minutes at a pressure of 8 Pa to obtain a silicon nitride ceramic piece C;

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

[0065] Comparative Example 2: Based on Example 1, the cleaning method in the prior art is adopted, and the other processes remain 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 the solvent in sequence 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 165Mpa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in 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 3Mpa and kept warm for 1.2 hours; after reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 is 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 piece B in a vacuum of 8×10 -4 Pa is heated to 250°C and kept warm for 1.5 hours. Silicon is evaporated under a pressure of 6.5kv, and then argon and methane gases are introduced to form surface bonding. After polishing, silicon nitride ceramic wafers are obtained.

[0071] Comparative Example 3: Based on Example 1, only one cleaning is used, and the other processes remain 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 the solvent in sequence 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 165Mpa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in 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 3Mpa and kept warm for 1.2 hours; after reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 ℃ to obtain the silicon nitride ceramic piece B;

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

[0077] Comparative Example 4: Based on Example 1, acid etching is not used, and the other processes remain 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 the solvent in sequence 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 165Mpa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in 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 3Mpa and kept warm for 1.2 hours; after reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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 2 mm, the cleaning angle to 25°, the cleaning distance to 15 cm, and the cleaning pressure to 4×10 5 The pretreated silicon nitride ceramic was cleaned once for 15 min at 400 °C to obtain silicon nitride ceramic sheet A;

[0081] Step 4: In a mixed atmosphere of hydrogen and argon with a mass ratio of 1:1, the radio frequency power is set to 50 W, and the silicon nitride ceramic sheet A is cleaned for a second time for 30 minutes at a pressure of 8 Pa to obtain a silicon nitride ceramic sheet B;

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

[0083] Comparative Example 5: Based on Example 1, the content of modified titanium nitride is too much, 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 for 2 to 4 hours under ultraviolet light, 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 for ultrasonic dispersion; 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 sintering aid are added to the solvent in sequence 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 165 MPa to obtain a silicon nitride ceramic body; the body is heated to 225°C at a rate of 5°C / min in a nitrogen atmosphere and kept warm for 35 minutes; the body is heated to 775°C at a rate of 5°C / min and kept warm for 12.5 minutes; the body is 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 reducing the pressure, the body is cooled to 800°C at a rate of 2°C / min and cooled with the furnace to obtain silicon nitride ceramics;

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 ℃ 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 is set to 50 W, and the silicon nitride ceramic piece B is cleaned for a second time for 30 minutes at a pressure of 8 Pa to obtain a silicon nitride ceramic piece C;

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

[0090] Comparative Example 6: Based on Example 1, the modified titanium nitride is changed to titanium nitride, and the other processes remain unchanged, specifically:

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

[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 silicon nitride ceramics 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, wherein the etching solution is prepared according to a mass ratio of 82.5:2.5:5:8, which is 97wt% phosphoric acid, 96wt% 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 ℃ 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 is set to 50 W, and the silicon nitride ceramic piece B is secondary cleaned for 30 minutes at a pressure of 8 Pa to obtain a silicon nitride ceramic piece C;

[0096] Step 6: Place the silicon nitride ceramic chip C in a vacuum of 8×10 -4 Pa is heated to 250°C and kept warm for 1.5 hours, silicon is evaporated under a pressure of 6.5kv, and then argon and methane gases are introduced to form surface bonding. After polishing, silicon nitride ceramic wafers are 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 Fine Ceramics Fracture Toughness Test Method-Single-Sided 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 its 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 enhance 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A surface treatment process for silicon nitride ceramic wafers, characterized in that: The following steps are involved: 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 processes in sequence to obtain a pretreated silicon nitride ceramic wafer; 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: Clean the silicon nitride ceramic chip A once to obtain the silicon nitride ceramic chip B; Step 5: Clean the silicon nitride ceramic piece B for a second time to obtain the silicon nitride ceramic piece C; 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.

2. The surface treatment process of a silicon nitride ceramic sheet 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, and grinding, rolling it at 150-180 MPa to obtain a silicon nitride ceramic embryo; 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 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 sheet according to claim 2, characterized in that: 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 trioxide in a mass ratio of 0.8 to 1.2:0.8 to 1.

2.

4. The surface treatment process of a silicon nitride ceramic sheet according to claim 3, characterized in that: The preparation method of the modified titanium nitride is: S1-1: Add vinyl ferrocene 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 reduced pressure distillation to obtain a ferrocene-based coupling agent; S1-2: Add 1 to 2 parts of titanium nitride to 80 to 85 wt% ethanol aqueous solution by weight to obtain a 0.1 to 0.2 g / mL dispersion; add 2.5 to 5 parts of nano-alumina sol for ultrasonic dispersion; stir evenly at 800 to 2000 r / min, add 0.5 to 1 part of ferrocene-based coupling agent, stir for 4 to 5 hours, centrifuge and dry to obtain modified titanium nitride.

5. The surface treatment process of a silicon nitride ceramic sheet according to claim 1, characterized in that: In step 2, the preparation process is: setting the 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 of 3-3.5mm from the center of the laser spot, and then setting the grinding number to 500-1000 meshes for double-sided grinding to obtain pretreated silicon nitride ceramics.

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

7. The surface treatment process of a silicon nitride ceramic sheet according to claim 6, 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.

8. The surface treatment process of a silicon nitride ceramic sheet according to claim 1, characterized in that: In step 4, the preparation process of the primary 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 400 ℃ and 800 ℃ to obtain the silicon nitride ceramic piece B.

9. The surface treatment process of a silicon nitride ceramic sheet according to claim 1, characterized in that: In step 5, the secondary cleaning preparation process 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 silicon nitride ceramic piece B is secondary cleaned for 20-40 minutes at a pressure of 3-13Pa to obtain silicon nitride ceramic piece C.

10. The surface treatment process of a silicon nitride ceramic sheet according to claim 1, characterized in that: In step 6, the preparation process is as follows: silicon nitride ceramic piece C is placed in a vacuum of 7.5×10 -4 ~8.5×10 -4 Pa is heated at 200-300°C 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. After polishing, silicon nitride ceramic wafers are obtained.

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