A method for preparing a wet-oxidized copper clad ceramic substrate

Abstract

The application provides a preparation method of a wet oxidation copper-clad ceramic substrate, which comprises the following steps: annealing, cleaning and pre-bending a copper sheet in sequence to obtain a pre-bent copper sheet; placing the pre-bent copper sheet in a carrier, adding an oxidizing solution into the carrier to perform oxidation treatment, and obtaining an oxidized copper sheet; and placing the oxidized copper sheet on the surface of a ceramic sheet to perform sintering, and obtaining a copper-clad ceramic substrate; wherein the oxidizing solution is potassium permanganate oxidizing solution, and the concentration of the potassium permanganate oxidizing solution is 3-5%. In the application, the preparation method of the copper-clad ceramic substrate is specifically designed, the copper sheet is oxidized in a wet manner, the foundation for the subsequent preparation of the copper-clad ceramic substrate is laid, the surface of the copper substrate is improved as a whole, the sintering yield of the product is improved, the production cost is reduced, and the demand for different crystal grains and roughness can be met.

Description

Technical Field

[0001] This invention belongs to the field of copper-clad ceramic substrate preparation technology, and relates to a method for preparing copper-clad ceramic substrates by wet oxidation. Background Technology

[0002] With the development of power semiconductors, the demand for copper-clad ceramic substrates is increasing. Currently, the pre-oxidation of copper sheets in copper-clad ceramic substrates is carried out by thermal oxidation.

[0003] The existing technical solution discloses a new process for removing oxide scale from the surface of copper alloy wire. The cleaning system used in this process includes copper alloy wire, a winding machine, an unwinding machine, a substrate, and a cleaning module. The cleaning module is located in the middle of the substrate. The cleaning module includes a pressing rod, a sleeve, a bracket, a weight, and a support wheel. The brackets are symmetrically fixedly installed on the substrate. Each bracket has a through groove in the middle, and a horizontal plate is fixedly connected to the top of the two brackets. The support wheel is hinged in the through groove. A sleeve is fitted around the outer ring of the copper alloy wire. A pressing rod is located around the outer ring of the sleeve. The top of the pressing rod is connected to the horizontal plate by a spring, and the bottom of the pressing rod is connected to the weight by a spring. A support plate is provided on each side of the pressing rod. A set of protrusions is provided on the side of the support plate near the pressing rod.

[0004] Existing technical solutions disclose a method to improve copper surface oxidation after soldering of copper-clad ceramic substrates. This involves processes such as acid pickling, water washing, alkaline washing, water washing again, and drying to remove the anti-oxidation film, thereby preventing oxidation of the copper-clad ceramic substrate after soldering at the client's location. Simultaneously, modified silica is added during the acid pickling process to prevent concentrated sulfuric acid from corroding the copper plate and affecting its performance. However, copper-clad ceramic substrates without an anti-oxidation layer can lead to color differences on the copper surface, and oxidation can occur during long-term transportation and exposure to moisture. This invention solves this problem through a nitrogen baking process.

[0005] The existing technical solution discloses the preparation and application of a partially oxidized silver-plated copper-clad substrate. Chemical silver deposition is performed on a copper-clad ceramic substrate to obtain a chemical silver deposition layer with a thickness of 5-10 μm. After film lamination on the copper-clad ceramic substrate, silver plating or silver soldering is used to obtain a silver-plated substrate. Electrolytic oxidation solution is used to oxidize the exposed silver layer surface, and after cleaning, drying, and hot sintering, a partially oxidized silver-plated copper-clad substrate is obtained.

[0006] However, current thermal oxidation and electrolytic oxidation methods suffer from uneven oxide layers due to factors such as equipment temperature, oxidation atmosphere, and electrolytic parameters, which easily lead to the generation of bubbles during sintering. Furthermore, the oxidation cost is relatively high. Therefore, there is an urgent need to design a wet oxidation method for preparing copper-clad ceramic substrates to overcome the shortcomings of existing technologies and meet the needs of practical applications. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a copper-clad ceramic substrate by wet oxidation. In this invention, through the specific design of the preparation method for the copper-clad ceramic substrate, a wet oxidation of copper sheets is adopted to lay the foundation for the subsequent preparation of the copper-clad ceramic substrate, thereby improving the overall surface of the copper substrate, increasing the sintering yield of the product, reducing production costs, and meeting the requirements of different grain sizes and roughness.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This invention provides a method for preparing a wet-process oxidized copper-clad ceramic substrate, the method comprising:

[0010] After the copper sheet is subjected to annealing, cleaning and pre-bending processes in sequence, a pre-bent copper sheet is obtained.

[0011] The pre-bent copper sheet is placed in a carrier, and an oxidation solution is added to the carrier for oxidation treatment to obtain an oxide copper sheet.

[0012] The copper oxide sheet is placed on the surface of the ceramic sheet and sintered to obtain a copper-clad ceramic substrate;

[0013] The oxidizing solution is a potassium permanganate oxidizing solution, and the concentration of the potassium permanganate oxidizing solution is 3-5%, for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] In this invention, by specifically designing the preparation method of copper-clad ceramic substrate, a wet oxidation method of copper sheets is adopted to lay the foundation for the subsequent preparation of copper-clad ceramic substrate, thereby improving the surface of the copper substrate, increasing the sintering yield of the product, reducing production costs, and meeting the requirements of different grain sizes and roughness.

[0015] It should be noted that traditional dry oxidation results in uneven oxide layers, high oxidation costs, low production efficiency, and surface roughness and grain size that do not meet customer requirements, leading to a low yield of sintered substrates. This invention uses a 3-5% potassium permanganate oxidation solution to oxidize copper sheets, which, compared to dry oxidation, can improve the surface of copper-clad substrates, increase product yield, and reduce production costs.

[0016] It should be noted that the shape, size, material, etc. of the carrier in this invention are not specifically limited. The carrier is mainly used to place copper sheets, and its shape and size can be consistent with the copper sheets. Those skilled in the art can make adaptive adjustments according to the actual situation.

[0017] As a preferred embodiment of the present invention, the annealing process is performed under vacuum or a protective atmosphere.

[0018] Preferably, the protective atmosphere is any one or a combination of at least two of nitrogen, helium, or argon.

[0019] It should be noted that the protective atmosphere in this invention can also be other inert gas atmospheres, such as neon.

[0020] As a preferred technical solution of the present invention, the annealing temperature is 400-500℃, for example, it can be 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] The annealing temperature in this invention is 400-500℃ because the oxidation effect of the copper sheet is optimal within this range. If it is outside this range, the copper sheet will not soften if the temperature is too low, and it will stick together if the temperature is too high.

[0022] Preferably, the annealing time is 60 to 120 minutes, for example, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] The annealing time in this invention is 60-120 minutes because the copper sheet cleaning effect is not good within this range. If it is outside this range, the time is too short and the copper sheet is not softened enough; if the time is too long, the efficiency is too low.

[0024] As a preferred embodiment of the present invention, the cleaning process is carried out in the following manner:

[0025] The annealed copper sheets are then subjected to rinsing and ultrasonic cleaning in sequence.

[0026] As a preferred technical solution of the present invention, the rinsing solution used in the rinsing treatment is a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide.

[0027] Preferably, in the mixture, the mass ratio of the acidic degreasing agent, the sulfuric acid, and the hydrogen peroxide is (5-6):(10-12):(80-85), for example, it can be 5:10:85, 5:10:12, 5.5:11:82, 5.5:12:81, 6:10:83, 6:11:84, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] It should be noted that the rinsing solution in this invention is a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide, and the mass ratio is limited to (5-6):(10-12):(80-85). This is because the oxidation effect of the copper sheet is optimal within this range. If it is not within this range, the cleaning effect of the copper sheet will be poor, which will affect the oxidation result.

[0029] It should be noted that the acidic degreasing agent in this invention is well known to those skilled in the art. It is formulated with a variety of surfactants and is a non-toxic, odorless, non-flammable neutral liquid. When added to pickling solution, it can both remove oil and promote the dissolution of rust and slow down the corrosion of the base metal by the acid.

[0030] As a preferred embodiment of the present invention, the ultrasonic cleaning uses pure water.

[0031] It should be noted that the pure water in this invention can be purified water, which is produced by using water that meets the hygiene standards for drinking water as the raw water and processing it through electrodialysis, ion exchange, reverse osmosis, distillation and other appropriate methods. It is sealed in a container, contains no additives, is colorless and transparent, and can be drunk directly.

[0032] Preferably, the ultrasonic cleaning time is 5 to 10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] As a preferred embodiment of the present invention, the pre-bending process is performed in the following manner:

[0034] The cleaned copper sheet is placed in a pre-bending mold for bending.

[0035] It should be noted that the shape, size, material, etc. of the pre-bending mold in this invention are not specifically limited. The pre-bending mold is mainly used to place the copper sheet and press it according to its curvature. Its shape and size can be consistent with the copper sheet. Those skilled in the art can make adaptive adjustments according to the actual situation.

[0036] Preferably, the curvature of the pre-bent copper sheet is R100 to R300 mm, for example, it can be R100 mm, R130 mm, R150 mm, R180 mm, R200 mm, R220 mm, R260 mm, R300 mm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In this invention, the curvature of the pre-bent copper sheet is R100 to R300 mm because the oxidation effect of the copper sheet is optimal within this range. If it is not within this range, bubbles will be generated during the sintering of the copper sheet.

[0038] As a preferred technical solution of the present invention, the temperature of the oxidation treatment is 30 to 50°C, for example, it can be 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] The oxidation temperature in this invention is 30-50°C because the oxidation effect of the copper sheet is optimal within this range. If it is outside this range, the oxidation effect of the copper sheet will be poor if the temperature is too high, and the oxidation of the copper sheet will not occur if the temperature is too low.

[0040] Preferably, the oxidation treatment time is 20 to 60 seconds, for example, it can be 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, after the oxidation treatment, the copper oxide sheet needs to be dried.

[0042] Preferably, the drying time is 5 to 10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the drying temperature is 70-80°C, for example, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] As a preferred embodiment of the present invention, the surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet.

[0045] Preferably, the sintering temperature is 1065 to 1080°C, for example, it can be 1065°C, 1068°C, 1070°C, 1072°C, 1074°C, 1076°C, 1078°C, 1080°C, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] The sintering temperature in this invention is 1065-1080℃ because the yield rate of the product is highest within this range. If the temperature is too low, the eutectic reaction of copper and ceramic cannot be carried out, and if the temperature is too high, the product is prone to deformation.

[0047] Preferably, the sintering time is 30 to 60 minutes, for example, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] Preferably, during sintering, the oxygen content in the sintering furnace is less than 50 ppm, for example, it can be 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0049] The oxygen content in the sintering furnace in this invention is below 50 ppm because the product yield is highest within this range. Sintering is carried out in an oxygen-free or micro-oxygen environment, and exceeding this range will cause abnormal sintering of the product.

[0050] As a preferred technical solution of the present invention, the preparation method specifically includes:

[0051] After the copper sheet is subjected to annealing, cleaning and pre-bending processes in sequence, a pre-bent copper sheet is obtained.

[0052] The pre-bent copper sheet is placed in a carrier, and an oxidation solution is added to the carrier for oxidation treatment to obtain an oxide copper sheet.

[0053] The copper oxide sheet is placed on the surface of the ceramic sheet and co-sintered to obtain a copper-clad ceramic substrate.

[0054] The oxidizing solution is a potassium permanganate oxidizing solution, and the concentration of the potassium permanganate oxidizing solution is 3-5%.

[0055] The annealing process is carried out under vacuum or a protective atmosphere, wherein the protective atmosphere is any one or a combination of at least two of nitrogen, helium or argon.

[0056] The annealing temperature is 400–500°C, and the annealing time is 60–120 min;

[0057] The cleaning process is carried out as follows: the annealed copper sheet is subjected to rinsing and ultrasonic cleaning in sequence;

[0058] The rinsing treatment uses a rinsing solution that is a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide. In the mixture, the mass ratio of the acidic degreasing agent, the sulfuric acid and the hydrogen peroxide is (5-6):(10-12):(80-85).

[0059] The ultrasonic cleaning uses pure water, and the ultrasonic cleaning time is 5 to 10 minutes.

[0060] The pre-bending process is carried out as follows: the cleaned copper sheet is placed in the pre-bending mold for bending.

[0061] The curvature of the pre-bent copper sheet is R100~R300mm;

[0062] The oxidation treatment temperature is 30–50°C, and the oxidation treatment time is 20–60 seconds.

[0063] After the oxidation treatment, the copper oxide sheet needs to be dried for 5 to 10 minutes at a temperature of 70 to 80°C.

[0064] The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet. The sintering temperature is 1065-1080℃, the sintering time is 30-60 min, and the oxygen content in the sintering furnace is less than 50 ppm during sintering.

[0065] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] In this invention, by specifically designing the preparation method of copper-clad ceramic substrate, a wet oxidation method of copper sheets is adopted to lay the foundation for the subsequent preparation of copper-clad ceramic substrate, thereby improving the surface of the copper substrate, increasing the sintering yield of the product, reducing production costs, and meeting the requirements of different grain sizes and roughness. Detailed Implementation

[0068] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0069] Example 1

[0070] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate, wherein:

[0071] After annealing, cleaning, and pre-bending, a copper sheet is obtained. The pre-bent copper sheet is placed in a carrier, and an oxidizing solution is added to the carrier for oxidation treatment to obtain a copper oxide sheet. The copper oxide sheet is placed on the surface of a ceramic sheet and co-sintered to obtain a copper-clad ceramic substrate. The oxidizing solution is a potassium permanganate oxidizing solution with a concentration of 3%.

[0072] The annealing process was carried out under vacuum at a temperature of 500°C for 60 minutes.

[0073] The cleaning process was carried out as follows: the annealed copper sheets were subjected to rinsing and ultrasonic cleaning in sequence; the rinsing solution used was a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide, in which the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide was 5:10:85; pure water was used for ultrasonic cleaning, and the ultrasonic cleaning time was 5 minutes.

[0074] The pre-bending process is carried out as follows: the cleaned copper sheet is placed in the pre-bending mold for bending; the curvature of the pre-bent copper sheet is R100mm.

[0075] The oxidation treatment temperature is 30℃ and the oxidation treatment time is 60s. After the oxidation treatment, the copper oxide sheet needs to be dried for 5 minutes at a temperature of 80℃.

[0076] The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet. The sintering temperature is 1065℃ and the sintering time is 60min. During sintering, the oxygen content in the sintering furnace is 20ppm.

[0077] Example 2

[0078] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate, wherein:

[0079] After annealing, cleaning, and pre-bending the copper sheet in sequence, a pre-bent copper sheet is obtained. The pre-bent copper sheet is placed in a carrier, and an oxidizing solution is added to the carrier for oxidation treatment to obtain a copper oxide sheet. The copper oxide sheet is placed on the surface of a ceramic sheet and co-sintered to obtain a copper-clad ceramic substrate. The oxidizing solution is a potassium permanganate oxidizing solution with a concentration of 4%.

[0080] The annealing process was carried out under a protective atmosphere of nitrogen at a temperature of 450°C for 80 minutes.

[0081] The cleaning process was carried out as follows: the annealed copper sheets were subjected to rinsing and ultrasonic cleaning in sequence; the rinsing solution used was a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide, in which the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide was 5.5:11:82; pure water was used for ultrasonic cleaning, and the ultrasonic cleaning time was 7 minutes.

[0082] The pre-bending process is carried out as follows: the cleaned copper sheet is placed in the pre-bending mold for bending; the curvature of the pre-bent copper sheet is R200mm.

[0083] The oxidation treatment temperature is 40℃ and the oxidation treatment time is 40s. After the oxidation treatment, the copper oxide sheet needs to be dried for 8 minutes at a temperature of 75℃.

[0084] The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet. The sintering temperature is 1070℃ and the sintering time is 45min. During sintering, the oxygen content in the sintering furnace is 35ppm.

[0085] Example 3

[0086] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate, wherein:

[0087] After annealing, cleaning and pre-bending the copper sheet in sequence, a pre-bent copper sheet is obtained. The pre-bent copper sheet is placed in a carrier and an oxidizing solution is added to the carrier for oxidation treatment to obtain a copper oxide sheet. The copper oxide sheet is placed on the surface of a ceramic sheet and co-sintered to obtain a copper-clad ceramic substrate. The oxidizing solution is a potassium permanganate oxidizing solution with a concentration of 5%.

[0088] The annealing process was carried out under a protective atmosphere of argon at a temperature of 400℃ for 120 minutes.

[0089] The cleaning process was carried out as follows: the annealed copper sheets were subjected to rinsing and ultrasonic cleaning in sequence; the rinsing solution used was a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide, in which the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide was 6:12:82; the ultrasonic cleaning used pure water and the ultrasonic cleaning time was 10 minutes.

[0090] The pre-bending process is carried out as follows: the cleaned copper sheet is placed in the pre-bending mold for bending; the curvature of the pre-bent copper sheet is R300mm.

[0091] The oxidation treatment temperature is 50℃ and the oxidation treatment time is 20s. After the oxidation treatment, the copper oxide sheet needs to be dried for 10 minutes at a temperature of 70℃.

[0092] The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet. The sintering temperature is 1080℃ and the sintering time is 30min. During sintering, the oxygen content in the sintering furnace is 50ppm.

[0093] Example 4

[0094] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the annealing temperature is 380°C, while other parameters and experimental conditions are the same as in Embodiment 1.

[0095] Example 5

[0096] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the annealing temperature is 550°C, while other parameters and experimental conditions are the same as in Embodiment 1.

[0097] Example 6

[0098] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the annealing time is 55 min, while other parameters and experimental conditions are the same as in Embodiment 1.

[0099] Example 7

[0100] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the annealing time is 125 min, while other parameters and experimental conditions are the same as in Embodiment 1.

[0101] Example 8

[0102] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Example 1 is that the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide is 1:3:80, while other parameters and experimental conditions are the same as in Example 1.

[0103] Example 9

[0104] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide is 2:1.5:90, while other parameters and experimental conditions are the same as in Embodiment 1.

[0105] Example 10

[0106] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the curvature of the pre-bent copper sheet is R95mm, while other parameters and test conditions are the same as in Embodiment 1.

[0107] Example 11

[0108] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the curvature of the pre-bent copper sheet is R310mm, while other parameters and test conditions are the same as in Embodiment 1.

[0109] Example 12

[0110] This embodiment provides a method for preparing a copper-clad ceramic substrate by wet oxidation. The difference from Embodiment 1 is that the oxidation temperature is 28°C, while other parameters and experimental conditions are the same as in Embodiment 1.

[0111] Example 13

[0112] This embodiment provides a method for preparing a copper-clad ceramic substrate by wet oxidation. The difference from Embodiment 1 is that the oxidation temperature is 53°C, while other parameters and experimental conditions are the same as in Embodiment 1.

[0113] Example 14

[0114] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the sintering temperature is 1050℃, while other parameters and experimental conditions are the same as in Embodiment 1.

[0115] Example 15

[0116] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the sintering temperature is 1090℃, while other parameters and experimental conditions are the same as in Embodiment 1.

[0117] Example 16

[0118] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the oxygen content in the sintering furnace is 15 ppm, while other parameters and experimental conditions are the same as in Embodiment 1.

[0119] Example 17

[0120] This embodiment provides a method for preparing a wet-process oxidized copper-clad ceramic substrate. The difference from Embodiment 1 is that the oxygen content in the sintering furnace is 60 ppm, while other parameters and experimental conditions are the same as in Embodiment 1.

[0121] Comparative Example 1

[0122] This comparative example provides a method for preparing a copper-clad ceramic substrate. Unlike Example 1, this method does not use an oxidizing solution for oxidation, but all other parameters and experimental conditions are the same as in Example 1.

[0123] Grain testing was performed on the copper-clad ceramic substrates in the above embodiments and comparative examples, and the results are shown in Table 1 below.

[0124] Table 1. Test results of copper-clad ceramic substrates in the examples and comparative examples.

[0125] Example 1 120.3 Example 2 121.4 Example 3 123.1 Example 4 118.6 Example 5 115.3 Example 6 118.3 Example 7 119.4 Example 8 116.2 Example 9 117.9 Example 10 114.2 Example 11 113.8 Example 12 118.5 Example 13 119.6 Example 14 111.5 Example 15 112.4 Example 16 115.2 Example 17 119.8 Comparative Example 1 70.2

[0126] From Table 1 above, we can see that:

[0127] The test data of copper-clad ceramic substrates in Examples 1-3 are as follows: This is because the present invention limits the annealing temperature to 400-500°C, which optimizes the grain detection of the copper-clad ceramic substrate.

[0128] The test data of copper-clad ceramic substrates in Examples 1-3 are based on the test data of copper-clad ceramic substrates in Examples 6 and 7. This is because the present invention limits the annealing time to 60-120 min, which optimizes the grain detection of the copper-clad ceramic substrate.

[0129] The test data of copper-clad ceramic substrates in Examples 1-3 are based on the test data of copper-clad ceramic substrates in Examples 8 and 9. This is because the present invention limits the mass ratio of acidic degreasing agent, sulfuric acid and hydrogen peroxide to (5-6):(10-12):(80-85), which optimizes the grain detection of copper-clad ceramic substrates.

[0130] The test data of copper-clad ceramic substrates in Examples 1-3 are as follows: This is because the present invention limits the curvature of the pre-bent copper sheet to R100~R300mm, so that the grain detection of the copper-clad ceramic substrate is optimal.

[0131] The test data of copper-clad ceramic substrates in Examples 1-3 are as follows: This is because the present invention limits the oxidation treatment temperature to 30-50°C, which optimizes the grain detection of the copper-clad ceramic substrate.

[0132] The test data of copper-clad ceramic substrates in Examples 1-3 are as follows: This is because the sintering temperature is limited to 1065-1080℃ in this invention, which makes the grain detection of copper-clad ceramic substrates optimal.

[0133] The test data of copper-clad ceramic substrates in Examples 1-3 are as follows: This is because the present invention limits the oxygen content in the sintering furnace to 20-50 ppm, which optimizes the grain detection of the copper-clad ceramic substrate.

[0134] The test data of copper-clad ceramic substrates in Examples 1-3 are different from those of the copper-clad ceramic substrate in Comparative Example 1. This is because the present invention uses an oxidizing solution to oxidize copper sheets, which can improve the surface of the copper-clad substrate, increase the product yield, and reduce production costs compared to dry oxidation.

[0135] In summary, this invention, through the specific design of the preparation method for copper-clad ceramic substrates, adopts a wet oxidation method for copper sheets, laying the foundation for the subsequent preparation of copper-clad ceramic substrates, improving the overall surface of the copper substrate, increasing the sintering yield of the product, reducing production costs, and meeting the requirements of different grain sizes and roughness.

[0136] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0137] The present invention has been illustrated with the above embodiments to explain the detailed method of the present invention. However, the present invention is not limited to the detailed method described above, that is, it does not mean that the present invention must rely on the detailed method described above to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a wet-process copper-clad ceramic substrate, characterized in that, The preparation method includes: After the copper sheet is subjected to annealing, cleaning and pre-bending processes in sequence, a pre-bent copper sheet is obtained. The pre-bent copper sheet is placed in a carrier, and an oxidation solution is added to the carrier for oxidation treatment to obtain an oxide copper sheet. The copper oxide sheet is placed on the surface of the ceramic sheet and sintered to obtain a copper-clad ceramic substrate; The annealing temperature is 400~500℃; The cleaning process is carried out in the following manner: The annealed copper sheets are subjected to rinsing and ultrasonic cleaning in sequence; the rinsing solution used in the rinsing process is a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide in a mass ratio of (5~6):(10~12):(80~85); The pre-bending process is performed as follows: The cleaned copper sheet is placed in a pre-bending mold for bending; the curvature of the pre-bent copper sheet is R100~R300mm. The oxidizing solution is a potassium permanganate oxidizing solution, and the concentration of the potassium permanganate oxidizing solution is 3-5%; The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet; the sintering temperature is 1065~1080℃.

2. The preparation method according to claim 1, characterized in that, The annealing process is performed under vacuum or a protective atmosphere.

3. The preparation method according to claim 2, characterized in that, The protective atmosphere is any one or a combination of at least two of nitrogen, helium, or argon.

4. The preparation method according to claim 1, characterized in that, The annealing process takes 60 to 120 minutes.

5. The preparation method according to claim 1, characterized in that, The ultrasonic cleaning process uses pure water.

6. The preparation method according to claim 1, characterized in that, The ultrasonic cleaning time is 5-10 minutes.

7. The preparation method according to claim 1, characterized in that, The oxidation treatment temperature is 30~50℃.

8. The preparation method according to claim 1, characterized in that, The oxidation treatment time is 20~60s.

9. The preparation method according to claim 1, characterized in that, After the oxidation treatment, the copper oxide sheet needs to be dried.

10. The preparation method according to claim 1, characterized in that, The sintering time is 30-60 minutes.

11. The preparation method according to claim 1, characterized in that, During sintering, the oxygen content in the sintering furnace is below 50 ppm.

12. The preparation method according to claim 1, characterized in that, The preparation method specifically includes: After the copper sheet is subjected to annealing, cleaning and pre-bending processes in sequence, a pre-bent copper sheet is obtained. The pre-bent copper sheet is placed in a carrier, and an oxidation solution is added to the carrier for oxidation treatment to obtain an oxide copper sheet. The copper oxide sheet is placed on the surface of the ceramic sheet and co-sintered to obtain a copper-clad ceramic substrate. The oxidizing solution is a potassium permanganate oxidizing solution, and the concentration of the potassium permanganate oxidizing solution is 3-5%. The annealing process is carried out under vacuum or a protective atmosphere, wherein the protective atmosphere is any one or a combination of at least two of nitrogen, helium or argon. The annealing temperature is 400~500℃, and the annealing time is 60~120min; The cleaning process is carried out as follows: the annealed copper sheet is subjected to rinsing and ultrasonic cleaning in sequence; The rinsing treatment uses a rinsing solution that is a mixture of acidic degreasing agent, sulfuric acid and hydrogen peroxide. In the mixture, the mass ratio of the acidic degreasing agent, the sulfuric acid and the hydrogen peroxide is (5~6):(10~12):(80~85). The ultrasonic cleaning uses pure water, and the ultrasonic cleaning time is 5-10 minutes. The pre-bending process is carried out as follows: the cleaned copper sheet is placed in the pre-bending mold for bending. The curvature of the pre-bent copper sheet is R100~R300mm; The oxidation treatment temperature is 30~50℃, and the oxidation treatment time is 20~60s; After the oxidation treatment, the copper oxide sheet needs to be dried for 5 to 10 minutes at a temperature of 70 to 80°C. The surface area of ​​the copper oxide sheet is smaller than that of the ceramic sheet. The sintering temperature is 1065~1080℃, the sintering time is 30~60min, and the oxygen content in the sintering furnace is less than 50ppm during sintering.