Micro-etching method of silicon nitride ceramic chip

Abstract

The invention discloses a silicon nitride ceramic chip micro-etching method, and relates to the technical field of ceramic chip micro-etching, and the silicon nitride ceramic chip micro-etching method comprises the following operation steps: S1, silicon nitride ceramic is cut, cleaned and dried to obtain a substrate; s2, sequentially adding dilute sulphuric acid, an environment-friendly additive, a surfactant and a buffer agent into deionized water, and homogenizing to obtain a digestion solution; and S3, placing the substrate in the digestion solution, carrying out microwave digestion treatment, cleaning, and drying to obtain the micro-etched silicon nitride ceramic chip.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic sheet micro-etching, in particular to a method for micro-etching a silicon nitride ceramic sheet. Background Art

[0002] Silicon nitride ceramics are widely used in electronics, electrical, aerospace and other fields due to their excellent mechanical properties, high thermal conductivity, high temperature resistance, corrosion resistance and other characteristics, especially in ceramic copper-clad substrates (AMB). However, the high chemical stability of silicon nitride ceramics also makes its surface treatment and etching process face great challenges.

[0003] Traditional surface etching methods mainly include wet etching and dry etching. Among them, wet etching usually uses strong acid or strong alkaline solutions (such as hydrofluoric acid) for etching. However, the chemical inertness of silicon nitride leads to an extremely slow etching rate, and highly corrosive chemicals need to be used, which has great operational safety risks, difficult waste liquid treatment, and is prone to uneven etching, affecting material properties. Dry etching uses plasma or reactive gases for etching. Although the etching accuracy and uniformity are good, the equipment is complex, the cost is high, the processing efficiency is low, and it may cause damage to the substrate surface.

[0004] In the prior art, the highly corrosive chemicals (such as hydrofluoric acid) used in wet etching have high operating risks, and the waste liquid is difficult to handle, which poses a potential threat to the environment and operators; dry etching equipment is complex, maintenance costs are high, and the technical requirements of operators are high, which limits its large-scale application. In addition, the high chemical inertness of silicon nitride makes traditional etching methods inefficient and difficult to meet the needs of efficient production; process instability and local differences in chemical reactions often lead to uneven etching, affecting the consistency of device performance.

[0005] In view of the above problems, the present invention proposes a micro-etching method for silicon nitride ceramic wafers; this method significantly improves the etching rate and uniformity by utilizing the efficient transmission of microwave energy in a mild acidic environment, while avoiding the use of highly corrosive chemicals, and has higher operational safety and process stability. Summary of the invention

[0006] The object of the present invention is to provide a micro-etching method for silicon nitride ceramic sheets to solve the problems raised in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A micro-etching method for a silicon nitride ceramic wafer comprises the following steps:

[0009] S1: cutting, cleaning and drying the silicon nitride ceramic to obtain a substrate;

[0010] S2: Add dilute sulfuric acid, environmentally friendly additives, surfactants, and buffers into deionized water in sequence, and homogenize to obtain a digestion solution;

[0011] S3: placing the substrate in a digestion solution, subjecting it to microwave digestion treatment, cleaning and drying, and obtaining a micro-etched silicon nitride ceramic wafer.

[0012] In the scheme, the silicon nitride ceramics are cut and immersed in deionized water in an ultrasonic cleaner for 10 minutes for preliminary cleaning to remove most of the surface particles and soluble stains; then, they are transferred to an ultrasonic tank soaked in high-purity ethanol for deep cleaning and further cleaned for 5 minutes to completely remove organic pollutants; the surface of the substrate is then air-dried using high-purity nitrogen in a dust-free environment to ensure that there are no residual droplets and prevent possible secondary contamination during the drying process.

[0013] In the scheme, after the digestion process is completed, the substrate is immediately removed from the reaction vessel and first washed three times in deionized water to effectively remove the acidic residues on the surface; then double-washed with high-purity ethanol to further remove possible residual organic matter; finally, the substrate is air-dried in a dust-free environment using high-purity nitrogen to ensure that its surface is clean and free of any water marks or other residues.

[0014] The more optimized process conditions of the microwave digestion treatment are: microwave power of 1000-1500W, digestion temperature of 120-150°C, digestion pressure of 2.0MPa-2.5MPa, and reaction time of 10-20 minutes.

[0015] In the plan, the microwave power is 1000W to ensure sufficient energy supply to promote the reaction; the digestion temperature is strictly controlled at 120℃ to ensure that the reaction is carried out at the optimal temperature; the digestion pressure is controlled at 2.0Mpa to maintain the stability of the reaction system and prevent excessive reaction; the reaction time is controlled at 15 minutes, and real-time monitoring is carried out every 5 minutes to ensure the uniformity and controllability of the digestion reaction; if uneven or abnormal reaction is found, the operating parameters should be adjusted in time.

[0016] More optimally, the raw materials of the digestion solution include the following components: by mass percentage, 10-30wt% dilute sulfuric acid, 5-10wt% environmentally friendly additives, 0.1-0.5wt% surfactant, 1-3wt% buffer, and the rest is water.

[0017] In the scheme, water is pure water or deionized water.

[0018] Preferably, the buffer comprises one or both of dihydrogen phosphate or sodium acetate.

[0019] More optimally, the surfactant includes one or two of sodium lauryl sulfate and polyethylene glycol.

[0020] Preferably, the environmentally friendly additive includes one or more of citric acid, oxalic acid, and complex tannic acid.

[0021] More optimally, the environmentally friendly additive consists of citric acid and complex tannic acid in a mass ratio of 4:1.

[0022] A more optimized preparation method of the composite tannic acid is as follows: tannic acid, phytic acid, and vinylphosphonic acid are added to deionized water in sequence, the temperature is set to 65-75°C and stirred for 2-4 hours; deionized water, 2-mercaptopiperidine, and thermal initiator AIBN are then added, stirring is continued at 70-80°C for 4-8 hours, and the deionized water is removed under reduced pressure to obtain the composite tannic acid.

[0023] More optimally, the raw materials of the composite tannic acid include the following components: 1 part of tannic acid, 0.3-0.6 parts of phytic acid, 0.3-0.5 parts of vinylphosphonic acid, 0.1-0.2 parts of 2-mercaptopiperidine, and 0.002-0.0022 parts of thermal initiator AIBN.

[0024] More optimally, when adding the composite tannic acid, 0.02-0.03 wt % of polyether silicone oil needs to be added; the polyether silicone oil is one of the water-soluble polyether silicone oil and its derivatives.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention mainly achieves precise control of etching depth and significantly improves the etching speed of silicon nitride ceramics by adjusting the microwave power, digestion time and digestion solution concentration of microwave digestion technology; optimizes the digestion solution and uniformly distributes the microwave field during the micro-etching digestion process to ensure etching uniformity.

[0027] In the scheme, the digestion solution is made of 10-30wt% dilute sulfuric acid, 5-10wt% environmentally friendly additives, 0.1-0.5wt% surfactants, and 1-3wt% buffers; wherein the corrosion inhibitor is one or both of dihydrogen phosphate or sodium acetate; the surfactant is one or both of sodium dodecyl sulfate and polyethylene glycol; and the environmentally friendly additive is composed of citric acid and complex tannic acid in a mass ratio of 4:1.

[0028] Among them, environmentally friendly additives and low-concentration acid solutions are used to reduce environmental pollution; however, the low-concentration acid solution has a low etching rate on the ceramic substrate. This solution combines micro-etching digestion technology to increase the etching rate of the digestion solution on the ceramic substrate and improve the safety of etching;

[0029] In order to further improve the micro-etching effect of the digestion solution on the ceramic substrate, this scheme introduces composite tannic acid into the environmentally friendly additive; in the scheme, the synergistic conductivity of phytic acid, 2-mercaptopiperidine and vinylphosphonic acid can interact with microwaves, and promote the uniformity of microwave field distribution during the micro-etching digestion process by absorbing and dissipating microwave energy, thereby improving the yield rate of micro-etched ceramic sheets; among them, the composite tannic acid has good chelating properties and can effectively remove insoluble organic matter and metal particles; among them, phytic acid has good conductivity, can provide electrons, form a stable free radical structure, thereby promoting the conduction of electrons, and has a strong complexing ability with most metal ions, which also helps to improve its conductivity; the nitrogen atom on the piperidine ring of 2-mercaptopiperidine has a lone pair of electrons, which can combine with hydrogen ions in the solution to form positively charged ions under appropriate conditions, thereby helping to improve the conductivity during the micro-etching digestion process.

[0030] The phosphonic acid group in vinylphosphonic acid has certain acidity and reactivity; it can form complexes with some metal ions or silicon ions, thereby promoting the dissolution equilibrium of silicon nitride to move in the dissolution direction and accelerating the micro-etching and digestion process; and the formed complex can prevent the dissolved ions from redepositing on the ceramic surface to a certain extent, which is beneficial to the continuation of the micro-etching and digestion reaction.

[0031] However, in the scheme, the introduction of composite tannic acid will promote the generation of bubbles during the micro-etching process and reduce the yield rate of micro-etched ceramic sheets; therefore, when adding composite tannic acid in the scheme, a certain amount of water-soluble polyether silicone oil needs to be added; it has good surface activity and defoaming properties, can reduce the surface tension of the micro-etching solution, improve the spreading ability of the surfactant on the silicon nitride surface, and make the etching more uniform; thereby preventing excessive foam from being generated during the micro-etching process, so as to improve the etching effect and thus improve the yield rate.

[0032] In summary, in order to solve the problems of low etching rate, poor uniformity and operational safety of ceramic wafers in traditional etching processes; this scheme optimizes the composition of the digestion solution, introduces intelligent control and precisely controls the etching depth to achieve efficient, safe and controllable micro-etching treatment, thereby improving the yield rate of micro-etched ceramic wafers; in this scheme, the optimized digestion solution can be applied to a variety of ceramic materials, expanding the application scope of the technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 1000 times SEM image of the micro-etched silicon nitride ceramic sheet prepared in Example 1;

[0034] Figure 2 This is a 5000x SEM image of the micro-etched silicon nitride ceramic sheet prepared in Example 1;

[0035] Figure 31000 times SEM image of the micro-etched silicon nitride ceramic sheet prepared in Example 2;

[0036] Figure 4 This is a 5000x SEM image of the micro-etched silicon nitride ceramic wafer prepared in Example 2. DETAILED DESCRIPTION

[0037] In the following specific implementation methods, parts are parts by mass; the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] Embodiment 1: A method for micro-etching a silicon nitride ceramic wafer, comprising the following steps;

[0039] S1: Cut the silicon nitride ceramic into pieces with a size of 20 mm×20 mm and a thickness of 0.32 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to high-purity ethanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0040] S2: (1) adding dilute sulfuric acid, citric acid, sodium dodecyl sulfate, and sodium dihydrogen phosphate to deionized water in sequence, and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 20wt% dilute sulfuric acid, 5wt% citric acid, 0.2wt% sodium dodecyl sulfate, 1wt% sodium dihydrogen phosphate, and the rest is deionized water;

[0041] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 15 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and washing it with deionized water for 3 times, then ultrasonically cleaning it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0042] The process conditions of microwave digestion are as follows: microwave power is 1000W, digestion temperature is 120°C, and digestion pressure is 2.0Mpa.

[0043] Example 2: In order to further verify the applicability of the present invention, this example shows the process of micro-etching a silicon nitride ceramic substrate under different process conditions, including the following operating steps;

[0044] S1: Cut the silicon nitride ceramic into pieces with a size of 10 mm×10 mm and a thickness of 0.5 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to isopropanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0045] S2: (1) adding dilute sulfuric acid, citric acid, sodium dodecyl sulfate and sodium dihydrogen phosphate to deionized water in sequence and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 30wt% dilute sulfuric acid, 10wt% oxalic acid, 0.5wt% polyethylene glycol, 3wt% sodium acetate, and the rest is deionized water;

[0046] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 20 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and first washing it with deionized water for 5 times, then ultrasonically washing it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0047] The process conditions of microwave digestion are as follows: microwave power is 1500W, digestion temperature is 150°C, and digestion pressure is 2.5Mpa.

[0048] Example 3 is based on Example 1, except that, while introducing the composite tannic acid into the environmentally friendly additive, 0.02 wt% of water-soluble polyether silicone oil is added, and the steps include the following:

[0049] S1: Cut the silicon nitride ceramic into pieces with a size of 20 mm×20 mm and a thickness of 0.32 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to high-purity ethanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0050] S2: (1) 1 part of tannic acid, 0.5 part of phytic acid, and 0.3 part of vinylphosphonic acid were added to deionized water in sequence, and the temperature was set to 70° C. and stirred for 2 hours; deionized water, 0.15 part of 2-mercaptopiperidine, and 0.002 part of thermal initiator AIBN were then added, and the mixture was stirred at 75° C. for 6 hours, and the deionized water was removed under reduced pressure to obtain composite tannic acid;

[0051] The citric acid and the composite tannic acid are mixed in a mass ratio of 4:1 to obtain an environmentally friendly additive;

[0052] (2) adding dilute sulfuric acid, environmentally friendly additives, sodium dodecyl sulfate, and sodium dihydrogen phosphate to deionized water in sequence, and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 20wt% dilute sulfuric acid, 5wt% citric acid, 0.2wt% sodium dodecyl sulfate, 1wt% sodium dihydrogen phosphate, 0.02wt% water-soluble polyether silicone oil, and the rest is deionized water;

[0053] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 15 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and washing it with deionized water for 3 times, then ultrasonically cleaning it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0054] The process conditions of microwave digestion are as follows: microwave power is 1000W, digestion temperature is 120°C, and digestion pressure is 2.0Mpa.

[0055] Comparative Example 1 is based on Example 3: no water-soluble polyether silicone oil is added to the digestion solution;

[0056] S1: Cut the silicon nitride ceramic into pieces with a size of 20 mm×20 mm and a thickness of 0.32 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to high-purity ethanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0057] S2: (1) 1 part of tannic acid, 0.5 part of phytic acid, and 0.3 part of vinylphosphonic acid were added to deionized water in sequence, and the temperature was set to 70° C. and stirred for 2 hours; deionized water, 0.15 part of 2-mercaptopiperidine, and 0.002 part of thermal initiator AIBN were then added, and the mixture was stirred at 75° C. for 6 hours, and the deionized water was removed under reduced pressure to obtain composite tannic acid;

[0058] The citric acid and the composite tannic acid are mixed in a mass ratio of 4:1 to obtain an environmentally friendly additive;

[0059] (2) adding dilute sulfuric acid, environmentally friendly additives, sodium dodecyl sulfate, and sodium dihydrogen phosphate to deionized water in sequence, and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 20wt% dilute sulfuric acid, 5wt% citric acid, 0.2wt% sodium dodecyl sulfate, 1wt% sodium dihydrogen phosphate, and the rest is deionized water;

[0060] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 15 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and washing it with deionized water for 3 times, then ultrasonically cleaning it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0061] The process conditions of microwave digestion are as follows: microwave power is 1000W, digestion temperature is 120°C, and digestion pressure is 2.0Mpa.

[0062] Comparative Example 2 is based on Example 3: the difference is that no phytic acid is introduced into the composite tannic acid;

[0063] S1: Cut the silicon nitride ceramic into pieces with a size of 20 mm×20 mm and a thickness of 0.32 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to high-purity ethanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0064] S2: (1) 1 part of tannic acid and 0.3 parts of vinylphosphonic acid were added to deionized water in sequence, and the temperature was set to 70° C. and stirred for 2 hours; deionized water, 0.15 parts of 2-mercaptopiperidine, and 0.002 parts of thermal initiator AIBN were then added, and the mixture was stirred at 75° C. for 6 hours, and the deionized water was removed under reduced pressure to obtain composite tannic acid;

[0065] The citric acid and the composite tannic acid are mixed in a mass ratio of 4:1 to obtain an environmentally friendly additive;

[0066] (2) adding dilute sulfuric acid, environmentally friendly additives, sodium dodecyl sulfate, and sodium dihydrogen phosphate to deionized water in sequence, and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 20wt% dilute sulfuric acid, 5wt% citric acid, 0.2wt% sodium dodecyl sulfate, 1wt% sodium dihydrogen phosphate, 0.02wt% water-soluble polyether silicone oil, and the rest is deionized water;

[0067] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 15 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and washing it with deionized water for 3 times, then ultrasonically cleaning it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0068] The process conditions of microwave digestion are as follows: microwave power is 1000W, digestion temperature is 120°C, and digestion pressure is 2.0Mpa.

[0069] Comparative Example 3 is based on Example 3, except that the mass ratio of citric acid to the composite addition amount is 1:1;

[0070] S1: Cut the silicon nitride ceramic into pieces with a size of 20 mm×20 mm and a thickness of 0.32 mm; ultrasonically clean it in deionized water for 10 minutes, then transfer it to high-purity ethanol for ultrasonic cleaning for 5 minutes, and blow dry it with nitrogen to obtain a substrate;

[0071] S2: (1) 1 part of tannic acid, 0.5 part of phytic acid, and 0.3 part of vinylphosphonic acid were added to deionized water in sequence, and the temperature was set to 70° C. and stirred for 2 hours; deionized water, 0.15 part of 2-mercaptopiperidine, and 0.002 part of thermal initiator AIBN were then added, and the mixture was stirred at 75° C. for 6 hours, and the deionized water was removed under reduced pressure to obtain composite tannic acid;

[0072] The citric acid and the composite tannic acid are mixed in a mass ratio of 1:1 to obtain an environmentally friendly additive;

[0073] (2) adding dilute sulfuric acid, environmentally friendly additives, sodium dodecyl sulfate, and sodium dihydrogen phosphate to deionized water in sequence, and homogenizing to obtain a digestion solution; wherein the raw materials in the digestion solution include the following components: by mass percentage, 20wt% dilute sulfuric acid, 5wt% citric acid, 0.2wt% sodium dodecyl sulfate, 1wt% sodium dihydrogen phosphate, 0.02wt% water-soluble polyether silicone oil, and the rest is deionized water;

[0074] S3: placing the substrate in a digestion solution and subjecting it to microwave digestion for 15 minutes, during which real-time monitoring is performed every 5 minutes to ensure the uniformity and controllability of the digestion reaction, taking it out and washing it with deionized water for 3 times, then ultrasonically cleaning it in high-purity ethanol for 10 minutes, and drying it with nitrogen to obtain a micro-etched silicon nitride ceramic wafer;

[0075] The process conditions of microwave digestion are as follows: microwave power is 1000W, digestion temperature is 120°C, and digestion pressure is 2.0Mpa.

[0076] Testing: (1) Take 100 samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3, record the number of good products, and calculate the good product rates of Example 1 and Comparative Examples 1 to 3, as shown in Table 1;

[0077] (2) The surface roughness Ra of the micro-etched silicon nitride ceramic wafer was measured using a high-precision surface roughness measuring instrument. The roughness Ra changes of Examples 1 to 2 are shown in Table 2.

[0078] (3) The morphology of the silicon nitride substrate after etching in Examples 1 and 2 was observed using a scanning electron microscope (SEM), with the magnification set to 2000 times and 10000 times, respectively, to analyze the surface structural characteristics and uniformity to ensure that the etching effect reached the expected level; Figure 1 and Figure 2 shown.

[0079] Yield rate (%) Example 1 97 Example 2 96 Example 3 98 Comparative Example 1 92 Comparative Example 2 96 Comparative Example 3 89

[0080] Table 1

[0081]

[0082] Table 2

[0083] Conclusion: From the examples, we can see the effect of micro-etching on the surface structure of silicon nitride ceramic substrate under different conditions; the microwave digestion method provided by the present invention has good flexibility and adaptability, and the parameters can be adjusted according to actual needs to achieve the best etching effect; the surface roughness Ra of Example 1 is reduced from 0.228μm to 0.154μm, and the etching uniformity is good. Figures 1-2 The SEM image shows that there are no obvious defects on the surface; the surface roughness Ra of Example 2 is reduced from 0.194μm to 0.160μm, and the etching depth is uniform. Figures 3-4 The SEM images show that the surface structure is clear.

[0084] In the scheme, Comparative Example 1 is based on Example 3, and water-soluble polyether silicone oil is not added to the digestion solution, resulting in a decrease in the yield rate; because polyether silicone oil has good surface activity and defoaming properties, it can reduce the surface tension of the micro-etching solution, improve the spreading ability of the surfactant on the silicon nitride surface, and make the etching more uniform; thereby preventing excessive foam from being generated during the micro-etching process to improve the etching effect.

[0085] Comparative Example 2 is based on Example 3, but phytic acid is not introduced into the composite tannic acid, resulting in a decrease in the yield of the micro-etched silicon nitride ceramic tile; because phytic acid has good conductivity, it can provide electrons to form a stable free radical structure, thereby promoting the conduction of electrons, which helps to improve the conductivity during the micro-etching process, thereby promoting the uniform distribution of the microwave field.

[0086] Comparative Example 3 is based on Example 3, except that the mass ratio of citric acid to the composite additive is 1:1, which results in a decrease in the yield rate of the micro-etched silicon nitride ceramic sheet.

[0087] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A micro-etching method for a silicon nitride ceramic wafer, characterized in that: The steps include: S1: cutting, cleaning and drying the silicon nitride ceramic to obtain a substrate; S2: Add dilute sulfuric acid, environmentally friendly additives, surfactants, and buffers into deionized water in sequence, and homogenize to obtain a digestion solution; S3: placing the substrate in a digestion solution, subjecting it to microwave digestion treatment, cleaning and drying, and obtaining a micro-etched silicon nitride ceramic wafer.

2. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The process conditions of the microwave digestion treatment are: microwave power of 1000-1500W, digestion temperature of 120-150°C, digestion pressure of 2.0MPa-2.5MPa, and reaction time of 10-20 minutes.

3. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The raw materials of the digestion solution include the following components: by mass percentage, 10-30wt% of dilute sulfuric acid, 5-10wt% of environmentally friendly additives, 0.1-0.5wt% of surfactant, 1-3wt% of buffer, and the rest is water.

4. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The buffer comprises one or both of dihydrogen phosphate or sodium acetate.

5. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The surfactant includes one or two of sodium lauryl sulfate and polyethylene glycol.

6. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The environmentally friendly additive includes one or more of citric acid, oxalic acid, and complex tannic acid.

7. The micro-etching method of a silicon nitride ceramic sheet according to claim 1, characterized in that: The environmentally friendly additive consists of citric acid and composite tannic acid in a mass ratio of 4:

1.

8. The micro-etching method of a silicon nitride ceramic sheet according to claim 7, characterized in that: The preparation method of the composite tannic acid comprises: adding tannic acid, phytic acid and vinylphosphonic acid into deionized water in sequence, setting the temperature to 65-75° C. and stirring for 2-4 hours; then adding deionized water, 2-mercaptopiperidine and thermal initiator AIBN, continuing to stir at 70-80° C. for 4-8 hours, and removing the ionized water under reduced pressure to obtain the composite tannic acid.

9. The micro-etching method of a silicon nitride ceramic sheet according to claim 8, characterized in that: The raw materials of the composite tannic acid include the following components: 1 part of tannic acid, 0.3-0.6 parts of phytic acid, 0.3-0.5 parts of vinylphosphonic acid, 0.1-0.2 parts of 2-mercaptopiperidine, and 0.002-0.0022 parts of thermal initiator AIBN.

10. The micro-etching method of a silicon nitride ceramic sheet according to claim 8, characterized in that: When adding the composite tannic acid, 0.02-0.03 wt % of polyether silicone oil needs to be added; the polyether silicone oil is one of the water-soluble polyether silicone oil and its derivatives.

Images