A precision AMB ceramic circuit board and its preparation method

Abstract

The present invention relates to the technical field of surface treatment of ceramic substrates, and specifically to a precision AMB ceramic circuit board and a preparation method thereof. By sequentially performing three-step improvement treatments on the AMB ceramic copper-clad substrate, namely grinding, copper plating, and polishing, the morphology of the copper foil surface is changed; in addition, in the present invention, additives I and II are added to the electroplating solution, and the two further synergistically promote electroplating, thereby obtaining a smooth and dense copper surface on the ceramic copper-clad substrate. The improved AMB ceramic copper-clad substrate has a higher bonding strength with the chip, solving problems such as chip offset, weak bonding, and easy falling off. Therefore, the implementation of this method can greatly meet the packaging needs of different customers and is of great significance.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic substrate surface treatment, in particular to a precision AMB ceramic circuit board and a preparation method thereof. Background Art

[0002] Active Metal Brazing Ceramic Substrate (AMB) is an active metal brazing ceramic substrate developed based on DBC technology. At temperatures around 800°C, AgCu solder containing the active elements Ti and Zr wets and reacts at the ceramic-metal interface, achieving heterogeneous bonding between the ceramic and metal. AMB ceramic copper-clad substrates achieve this through a high-temperature chemical reaction between the ceramic and active metal solder paste. This results in a stronger bond and improved reliability, making them ideal for connectors or applications requiring high current carrying capacity and heat dissipation.

[0003] AMB ceramic copper-clad substrates belong to a category of ceramic heat dissipation substrates used in the industrial field. However, during the vacuum brazing (high-temperature sintering) process between the ceramic substrate and the metal copper foil, due to the influence of various uncontrollable factors, the copper foil surface cannot obtain good density and will also produce small "grains". In the post-processing process, the copper foil needs to be corroded by strong acidic liquid in multiple different processes. In particular, its surface needs to be etched with various patterns that meet the requirements of the relevant drawings. Therefore, it is inevitable that it will be over-corroded by chemical liquids. In addition, the grain boundaries of some copper foils will be more obvious after vacuum brazing, and the liquid will remain in such grain boundaries, which will accelerate the over-corrosion of the copper foil surface. At the same time, other foreign matter is easily mixed in the grain boundaries, which is difficult to clean in the subsequent process. As time goes on, the over-corrosion phenomenon will become more prominent, resulting in abnormal problems such as chip offset, loose bonding, and easy slipping during the attachment process of the AMB ceramic copper-clad substrate and the chip, which brings great trouble to the chip attachment link.

[0004] Based on this, the present invention will study how to eliminate the grains naturally formed during the vacuum brazing process of the AMB ceramic copper-clad substrate to obtain a smoother, denser and more flat metal surface, so as to solve the difficult problems such as chip offset, loose bonding, and easy slipping that occur in the later packaging process.

[0005] The present invention changes the surface morphology, grain size, roughness and flatness of the traditional AMB ceramic copper clad substrate through effective innovative technologies such as "grinding", "electroplating" and "polishing" on the surface of the AMB ceramic copper clad substrate, thereby improving the adhesion between the AMB ceramic copper clad substrate and the chip, and the bonding performance is stronger. Summary of the Invention

[0006] The object of the present invention is to provide a precision AMB ceramic circuit board and a preparation method thereof 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 precision AMB ceramic circuit board is prepared by first subjecting an AMB ceramic copper-clad substrate to a three-step improvement process of grinding, copper plating, and polishing, then etching a precision circuit pattern on its surface, and finally sequentially attaching a silver film and a chip to its surface and heating and curing them separately.

[0009] Furthermore, the method for preparing the precision AMB ceramic circuit board comprises the following steps:

[0010] S1: Grinding the AMB ceramic copper clad substrate;

[0011] S2: After S1, the AMB ceramic copper-clad substrate is copper-plated;

[0012] S3: After S2, the AMB ceramic copper clad substrate is polished and brushed;

[0013] S4: After S3, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0014] Furthermore, the grinding process is carried out by mechanical grinding, which is specifically as follows: the AMB ceramic copper-clad substrate is mechanically ground by ceramic brush 1 and ceramic brush 2 of a brush machine; wherein, the parameters of mechanical grinding are: grinding speed of 0.8~1.0m / min, current of ceramic brush 1 of 0.9~1.1A, current of ceramic brush 2 of 0.3~0.4A, and grinding thinning thickness of 15~35μm.

[0015] The thickness of the copper foil of the AMB ceramic copper clad substrate is reduced by mechanical grinding to facilitate subsequent copper plating and improve the morphology and quality of the copper foil on the ceramic copper clad substrate.

[0016] Furthermore, the ceramic brush needs to be tested for brush marks every time it grinds 1,500 AMB ceramic copper-clad substrates. If the brush marks are obviously uneven in thickness, the entire brush needs to be adjusted.

[0017] Furthermore, the copper plating is carried out by electroplating, and the specific process is: first, the ground AMB ceramic copper-clad substrate is degreased and activated in sequence, then placed in an electroplating solution for electroplating, and finally washed with hot water at 50-60°C and dried to complete the copper electroplating.

[0018] Furthermore, the specific process of the degreasing is: placing the ground AMB ceramic copper-clad substrate into an acidic degreasing agent, soaking it at 50-60°C for 2-3 minutes, taking it out, washing it with hot water at 50-60°C, and then washing it with overflow water twice to complete the degreasing.

[0019] Furthermore, the specific process of the activation is: placing the degreased AMB ceramic copper-clad substrate in 2-4wt% concentrated sulfuric acid, soaking for 1-2 minutes, taking it out, and washing it twice with overflow water to complete the activation.

[0020] Furthermore, the electroplating solution includes the following concentration components: copper sulfate 80-120 g / L, concentrated sulfuric acid 100-140 mL / L, chloride ion 60-100 ppm, additive I 5-15 mL / L, additive II 0.2-0.4 g / L, and the solvent is deionized water.

[0021] Furthermore, the preparation method of the additive I is as follows: (1) adding 5-bromo-2,2'-bipyridine to anhydrous ethanol, stirring and dissolving, and obtaining an ethanol solution of 5-bromo-2,2'-bipyridine; (2) adding a fatty alcohol ethoxylate to water, stirring and dissolving, and obtaining an aqueous solution of the fatty alcohol ethoxylate; (3) fully mixing the ethanol solution of 5-bromo-2,2'-bipyridine and the aqueous solution of the fatty alcohol ethoxylate to obtain additive I.

[0022] Furthermore, the additive I comprises the following concentration components: 8-16 g / L of 5-bromo-2,2'-bipyridine, 24-48 g / L of fatty alcohol ethoxylate, and the solvent is a 50 wt% ethanol solution.

[0023] Furthermore, the mass ratio of the 5-bromo-2,2'-bipyridine to the fatty alcohol ethoxylate is 1:3.

[0024] Additive I is composed of a mixture of 5-bromo-2,2'-bipyridine and fatty alcohol ethoxylates. 5-bromo-2,2'-bipyridine can promote electroplating within a certain concentration and has a key influence on the morphology and performance of the electroplated layer; the fatty alcohol ethoxylates can act as a non-ionic surfactant, which has the effect of reducing the surface tension of the electroplating solution, and can improve the pore filling ability of the electroplating solution, thereby making the coating crystals more dense and stable.

[0025] Furthermore, the preparation method of the additive II is as follows: (1) adding 4'-(3-pyridyl)-2,2':6',2"-terpyridine to dichloromethane, stirring and dissolving, to obtain a dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine; (2) adding cerium nitrate to methanol, stirring and dissolving, and then slowly adding the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine dropwise thereto, stirring and mixing for 1 to 2 hours, collecting the filtrate by filtration, and collecting the crystals after standing for 48 to 96 hours to obtain additive II.

[0026] Furthermore, the mass ratio of the 4'-(3-pyridyl)-2,2':6',2"-terpyridine to cerium nitrate is 2:1.

[0027] Additive II is prepared by forming a complex with 4'-(3-pyridyl)-2,2':6',2"-terpyridine and cerium nitrate. Adding the rare earth complex to the electroplating solution can promote electroplating, thereby facilitating the formation of a coating with a dense surface and good bonding strength. It can synergistically promote copper electroplating with Additive I, achieving an ideal bonding strength and surface quality of the copper foil surface.

[0028] Furthermore, the parameters of the electroplating process are: temperature of 40-50°C, current density of 1-3A / dm 2 The electroplating time is 2 to 3 hours, the cathode is copper, and the plating thickness is 25 to 50 μm.

[0029] The thickness of the copper foil that was ground off can be compensated by electroplating, and a copper foil with more uniform and dense quality can be obtained by electroplating.

[0030] Furthermore, the polishing brush is specifically as follows: after copper plating, the AMB ceramic copper-clad substrate is successively polished by the non-woven brush 1 and the non-woven brush 2 of the brush machine; the parameters of the polishing brush are: the polishing brush speed is 1.0~1.2m / min, the current of the non-woven brush 1 is 1.0~1.2A, and the current of the non-woven brush 2 is 0.9~1.1A.

[0031] After copper plating, the surface defects such as unevenness and spots can be removed by polishing and brushing.

[0032] Furthermore, the non-woven fabric brush needs to be replaced and adjusted after brushing 3,000 to 4,000 AMB ceramic copper-clad substrates.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention changes the metal morphology of the surface of the traditional AMB ceramic copper-clad substrate, specifically including: (1) eliminating the irregular and multi-grained appearance of the copper foil surface; (2) obtaining a smoother and denser copper foil surface;

[0035] 2. This invention solves the difficult problems of traditional AMB ceramic copper-clad substrate and chip being easily offset, loosely bonded, and easily slipped during attachment;

[0036] 3. The present invention adds additives I and II to the electroplating solution to improve the surface performance of the copper foil obtained by electroplating;

[0037] 4. The implementation of the present invention can better meet market demand, has great application prospects, and is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of the product of the present invention;

[0039] Figure 2 This is the metallographic image of the copper foil of the AMB ceramic copper-clad substrate before the three-step improvement treatment of grinding, copper plating and polishing;

[0040] Figure 3 This is the metallographic image of the copper foil of the AMB ceramic copper-clad substrate after three-step improvement treatment: grinding, copper plating, and polishing. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0042] It should be noted that the process parameters not specified in the following examples are all conventional conditions; the raw materials can be obtained from public commercial channels; and the water used is all deionized water.

[0043] In the following examples, a double-sided copper-clad AMB ceramic copper-clad substrate is selected for improvement treatment. The theoretical thickness of its single-layer copper foil is 0.8 mm, the theoretical thickness of the ceramic substrate is 0.32 mm, and the theoretical total thickness of the AMB ceramic copper-clad substrate is 0.8×2+0.32=1.92 mm.

[0044] Pre-preparation:

[0045] 1. Preparation of additive I: (1) Add 12 g of 5-bromo-2,2'-bipyridine to 300 mL of anhydrous ethanol and stir to dissolve to obtain an ethanol solution of 5-bromo-2,2'-bipyridine; (2) Add 36 g of fatty alcohol polyoxyethylene ether to 300 mL of deionized water and stir to dissolve to obtain an aqueous solution of fatty alcohol polyoxyethylene ether; (3) Fully mix the ethanol solution of 5-bromo-2,2'-bipyridine and the aqueous solution of fatty alcohol ethoxylate, and add 400 mL of 50 wt% ethanol solution to dilute to 1 L to obtain additive I.

[0046] 2. Preparation of Additive II: (1) Add 4 g of 4'-(3-pyridyl)-2,2':6',2"-terpyridine to 50 mL of dichloromethane, stir and dissolve, and obtain a dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine; (2) Add 2 g of cerium nitrate to 50 mL of methanol, stir and dissolve, and then slowly dropwise add the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine thereto, stir and mix for 1.5 hours, collect the filtrate by filtration, let it stand for 72 hours, and collect the crystals to obtain Additive II.

[0047] Example 1: A method for preparing a precision AMB ceramic circuit board:

[0048] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.916 mm;

[0049] S1: Grinding treatment:

[0050] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 31 μm, and an average thickness of 1.885 mm after grinding.

[0051] S2: Copper plating treatment:

[0052] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0053] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0054] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0055] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0056] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 43μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.928mm;

[0057] S3: Brushing treatment:

[0058] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0059] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0060] Example 2: A method for preparing a precision AMB ceramic circuit board:

[0061] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.906 mm;

[0062] S1: Grinding treatment:

[0063] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 19 μm, and an average thickness of 1.887 mm.

[0064] S2: Copper plating treatment:

[0065] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0066] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0067] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0068] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0069] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 49μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.936mm;

[0070] S3: Brushing treatment:

[0071] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0072] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0073] Example 3: A method for preparing a precision AMB ceramic circuit board:

[0074] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.911 mm;

[0075] S1: Grinding treatment:

[0076] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 22 μm, and an average thickness of 1.889 mm after grinding.

[0077] S2: Copper plating treatment:

[0078] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0079] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0080] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0081] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0082] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 44μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.933mm;

[0083] S3: Brushing treatment:

[0084] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0085] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0086] Example 4: A method for preparing a precision AMB ceramic circuit board:

[0087] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.914 mm;

[0088] S1: Grinding treatment:

[0089] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 33 μm, and an average thickness of 1.881 mm.

[0090] S2: Copper plating treatment:

[0091] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0092] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0093] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0094] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0095] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 50μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.931mm;

[0096] S3: Brushing treatment:

[0097] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0098] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0099] Example 5: A method for preparing a precision AMB ceramic circuit board:

[0100] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.919 mm;

[0101] S1: Grinding treatment:

[0102] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 25 μm, and an average thickness of 1.894 mm after grinding.

[0103] S2: Copper plating treatment:

[0104] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0105] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0106] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0107] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0108] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 40μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.934mm;

[0109] S3: Brushing treatment:

[0110] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0111] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0112] Example 6: A method for preparing a precision AMB ceramic circuit board:

[0113] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.917 mm;

[0114] S1: Grinding treatment:

[0115] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction thickness of 30 μm, and an average thickness of 1.887 mm after grinding.

[0116] S2: Copper plating treatment:

[0117] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0118] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0119] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0120] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive I 10mL / L, additive II 0.3g / L, and the solvent is deionized water;

[0121] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 44μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.931mm;

[0122] S3: Brushing treatment:

[0123] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0124] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0125] Based on Example 1, a control experiment was conducted to set comparative examples 1 to 3:

[0126] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: Additive I and Additive II are not added to the electroplating solution, and other processes remain unchanged, specifically:

[0127] A method for preparing a precision AMB ceramic circuit board:

[0128] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.921 mm;

[0129] S1: Grinding treatment:

[0130] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 25 μm, and an average thickness of 1.896 mm after grinding.

[0131] S2: Copper plating treatment:

[0132] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0133] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0134] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0135] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, and the solvent is deionized water;

[0136] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 31μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.927mm;

[0137] S3: Brushing treatment:

[0138] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0139] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0140] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: Additive II is not added to the electroplating solution, and other processes remain unchanged, specifically:

[0141] A method for preparing a precision AMB ceramic circuit board:

[0142] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.923 mm;

[0143] S1: Grinding treatment:

[0144] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction thickness of 30 μm, and an average thickness of 1.893 mm after grinding.

[0145] S2: Copper plating treatment:

[0146] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0147] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0148] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0149] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive 110mL / L, and the solvent is deionized water;

[0150] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2 , the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 31μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.924mm;

[0151] S3: Brushing treatment:

[0152] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0153] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0154] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: Additive I is not added to the electroplating solution, and other processes remain unchanged, specifically:

[0155] A method for preparing a precision AMB ceramic circuit board:

[0156] In this embodiment, the actual average thickness of the AMB ceramic copper-clad substrate before improvement is 1.918 mm;

[0157] S1: Grinding treatment:

[0158] The AMB copper-clad ceramic substrate was mechanically ground using brushes 1 and 2 of a brushing machine. The mechanical grinding parameters were: a grinding speed of 0.9 m / min, a current of 1 A for brush 1, a current of 0.35 A for brush 2, a grinding reduction of 29 μm, and an average thickness of 1.889 mm.

[0159] S2: Copper plating treatment:

[0160] (1) Place the ground AMB ceramic copper-clad substrate in a TD-121 acidic degreasing agent, soak it at 55°C for 2.5 minutes, take it out, rinse it with hot water at 55°C, and then rinse it twice with overflow water to complete the degreasing;

[0161] (2) The degreased AMB ceramic copper-clad substrate was placed in 3 wt% concentrated sulfuric acid for 1.5 min, taken out, and washed twice with overflow water to complete activation;

[0162] (3) placing the activated AMB ceramic copper-clad substrate in an electroplating solution for electroplating, and finally washing and drying it with hot water at 55°C to complete the copper electroplating;

[0163] The electroplating solution includes the following concentration components: copper sulfate 100g / L, concentrated sulfuric acid 120mL / L, chloride ion 80ppm, additive II 0.3g / L, and the solvent is deionized water;

[0164] The parameters of the electroplating process are: temperature 45°C, current density 2A / dm 2, the electroplating time is 2.5h, the cathode is a copper ball, and the coating thickness is 35μm, that is, the average thickness of the AMB ceramic copper-clad substrate after electroplating is 1.924mm;

[0165] S3: Brushing treatment:

[0166] After electroplating, the AMB ceramic copper-clad substrate was polished by nylon brush 1 and nylon brush 2 of the brushing machine. The parameters of the polishing were as follows: the polishing speed was 1.1 m / min, the current of nylon brush 1 was 1.1 A, and the current of nylon brush 2 was 1 A.

[0167] S4: After the polishing treatment, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board.

[0168] The average thickness changes of the AMB ceramic copper-clad substrates in the above Examples 1 to 6 and Comparative Examples 1 to 3 before and after the S1 to S2 improvement treatments are shown in Table 1 below:

[0169] Table 1

[0170]

[0171] Performance comparison: The roughness, wire bonding force, hardness, and thermal shock of the AMB ceramic copper-clad substrates in Examples 1 to 6 and Comparative Examples 1 to 3 before and after the S1 to S3 improvement treatments are compared. See Tables 2 to 5 below for details:

[0172] Among them, the bonding force: 300μm aluminum wire is used to conduct bonding test on the surface of AMB ceramic copper clad substrate;

[0173] Thermal shock: Heat the AMB ceramic copper-clad substrate at 355°C for 130 seconds, then cool it to 25°C for 45 seconds. Repeat this cycle 15 times to observe whether the copper clad layer falls off or experiences other abnormalities.

[0174] Table 2 Roughness comparison

[0175]

[0176] Table 3 Comparison of stringing force

[0177]

[0178] Table 4 Hardness (HV10) comparison

[0179]

[0180]

[0181] Table 5 Comparison of hot and cold shock

[0182]

[0183] From the test results in Tables 2 to 5 above, it can be seen that:

[0184] (1) The relevant data of the embodiment are better than those of the comparative example, indicating that Additive I and Additive II play an important role in copper electroplating;

[0185] The following is a comparison of the relevant test results of the examples, as shown in (2)(3)(4)(5):

[0186] (2) Roughness: The surface of the AMB ceramic copper-clad substrate after grinding, electroplating and polishing is smoother and denser, with a smaller roughness value, Ra avg =0.240μm>0.964μm,Rz avg =2.344μm>7.167μm, Rmax avg =4.448μm>11.514μm;

[0187] (3) In terms of wire bonding force: the wire bonding force of AMB ceramic copper clad substrate after grinding, electroplating and polishing is better. avg 1635.7g / mm>1386.0g / mm;

[0188] (4) In terms of hardness: the hardness of the AMB ceramic copper-clad substrate after grinding + electroplating + polishing is higher. avg =78.94Gpa>46.56Gpa;

[0189] (5) Regarding hot and cold shock: neither of them showed any shedding or abnormality;

[0190] In summary, after vacuum brazing, conventional AMB ceramic copper-clad substrates naturally produce irregular grains on the surface of the copper foil. These grains are rough and have poor density, which can lead to varying degrees of chip offset, loose bonding, and even chip shedding during subsequent chip attachment. However, the present invention takes a new approach by using a three-step improvement process of "grinding + copper plating + polishing" on the surface of the copper foil sintered by the traditional AMB process. This changes the copper foil's morphology, making the surface free of grains, smooth and dense, and providing a higher bonding strength with the chip, solving the problems of chip offset, loose bonding, and shedding. The implementation of this method can meet the packaging needs of different customers.

[0191] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing a precision AMB ceramic circuit board, characterized by: The following steps are involved: S1: Grinding the AMB ceramic copper clad substrate; S2: After S1, the AMB ceramic copper-clad substrate is copper-plated; S3: After S2, the AMB ceramic copper clad substrate is polished and brushed; S4: After S3, a precise circuit pattern is etched on the surface of the AMB ceramic copper-clad substrate, and then a silver film and a chip are attached to the surface in sequence and heated and cured respectively to obtain a precise AMB ceramic circuit board; Among them, in S2, the copper plating is carried out by electroplating, and the specific process is: first, the ground AMB ceramic copper-clad substrate is degreased and activated in sequence, then placed in the electroplating solution for electroplating, and finally washed and dried with hot water at 50~60℃ to complete the copper electroplating.

2. The method for preparing a precision AMB ceramic circuit board according to claim 1, wherein: The grinding process is performed by mechanical grinding, which is specifically as follows: the AMB ceramic copper clad substrate is mechanically ground by ceramic brush 1 and ceramic brush 2 of a brushing machine in sequence; The parameters of mechanical grinding are as follows: grinding speed is 0.8~1.0m / min, current of ceramic brush 1 is 0.9~1.1A, current of ceramic brush 2 is 0.3~0.4A, and grinding thinning thickness is 15~35μm.

3. The method for preparing a precision AMB ceramic circuit board according to claim 1, wherein: The electroplating solution comprises the following components in concentrations: 80-120 g / L copper sulfate, 100-140 mL / L concentrated sulfuric acid, 60-100 ppm chloride ions, 5-15 mL / L additive I, 0.2-0.4 g / L additive II, and the solvent is deionized water; The preparation method of the additive I is as follows: (1) adding 5-bromo-2,2'-bipyridine to anhydrous ethanol, stirring and dissolving, and obtaining an ethanol solution of 5-bromo-2,2'-bipyridine; (2) adding a fatty alcohol ethoxylate to water, stirring and dissolving, and obtaining an aqueous solution of the fatty alcohol ethoxylate; (3) fully mixing the ethanol solution of 5-bromo-2,2'-bipyridine and the aqueous solution of the fatty alcohol ethoxylate, and adding 50 wt% ethanol solution to the fixed volume to obtain the additive I; Additive I includes the following concentration components: 8-16 g / L of 5-bromo-2,2'-bipyridine, 24-48 g / L of fatty alcohol ethoxylate, and the solvent is a 50 wt% ethanol solution; The preparation method of the additive II is as follows: (1) adding 4'-(3-pyridyl)-2,2':6',2''-terpyridine to dichloromethane, stirring and dissolving, and obtaining a dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2''-terpyridine; (2) adding cerium nitrate to methanol, stirring and dissolving, and then slowly adding the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2''-terpyridine thereto, stirring and mixing for 1-2 hours, collecting the filtrate by filtration, and collecting the crystals after standing for 48-96 hours to obtain the additive II; The mass ratio of the 4'-(3-pyridyl)-2,2':6',2''-terpyridine and cerium nitrate is 2:

1.

4. The method for preparing a precision AMB ceramic circuit board according to claim 3, wherein: The mass ratio of the 5-bromo-2,2'-bipyridine to the fatty alcohol ethoxylate is 1:

3.

5. The method for preparing a precision AMB ceramic circuit board according to claim 1, characterized in that: The parameters of the electroplating treatment are: temperature of 40-50° C., current density of 1-3 A / dm 2 , electroplating time of 2-3 h, cathode of copper, and coating thickness of 25-50 μm.

6. The method for preparing a precision AMB ceramic circuit board according to claim 1, characterized in that: The specific method of the brushing is as follows: after copper plating, the AMB ceramic copper-clad substrate is successively brushed by the non-woven brush 1 and the non-woven brush 2 of the brushing machine; the parameters of the brushing are: the brushing speed is 1.0~1.2m / min, the current of the non-woven brush 1 is 1.0~1.2A, and the current of the non-woven brush 2 is 0.9~1.1A.

7. A precision AMB ceramic circuit board prepared by the method for preparing a precision AMB ceramic circuit board according to any one of claims 1 to 6.

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