Precise AMB ceramic circuit board and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrate surface treatment, in particular to a precise AMB ceramic circuit board and a preparation method thereof. The AMB ceramic copper-clad substrate is sequentially subjected to three-step improvement treatment including grinding, copper plating and polishing and brushing, so that the appearance of the surface of the copper foil is changed; in addition, the additive I and the additive II are added into the electroplating liquid and further cooperate to promote electroplating, and a smooth and compact copper surface is obtained on the ceramic copper-clad substrate. The improved AMB ceramic copper-clad substrate and the chip are higher in bonding strength, the problems that the chip deviates, the bonding force is not firm, and the chip is prone to falling off are solved, and therefore the implementation of the method can greatly meet the packaging requirements of different clients, and the method has important significance.

Description

Technical Field

[0001] The 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] AMB (Active Metal Brazing Ceramic Substrate) is developed on the basis of DBC technology. At a high temperature of about 800°C, AgCu solder containing active elements Ti and Zr wets and reacts at the interface between ceramic and metal, thereby achieving heterogeneous bonding between ceramic and metal. AMB ceramic copper-clad substrate is achieved by chemical reaction between ceramic and active metal solder paste at high temperature, so it has higher bonding strength and better reliability, and is extremely suitable for connectors or scenarios with high current carrying and heat dissipation requirements.

[0003] AMB ceramic copper-clad substrate belongs 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 fine "grains". In the post-processing process, the copper foil needs to be corroded by strong acid liquid in multiple different processes, especially its surface needs to be etched with various graphics that meet the requirements of relevant drawings, so it is inevitable that it will be over-corroded by chemical liquid. In addition, the grain boundaries of some copper foils will be more obvious after vacuum brazing, and the liquid will remain in this grain boundary, which will accelerate the over-corrosion of the copper foil surface. At the same time, other foreign matter is also easily mixed in the grain boundary, which is difficult to clean in the subsequent process. With the extension of time, the over-corrosion phenomenon will become more prominent, resulting in abnormal problems such as chip offset, loose bonding, and easy slipping during the AMB ceramic copper-clad substrate and chip attachment process, 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 to solve the difficult problems of chip offset, loose bonding, and easy slipping that occur in the later packaging process.

[0005] The present invention changes the surface morphology, grains, roughness and flatness of the traditional AMB ceramic copper clad substrate by using effective innovative technologies such as "grinding", "electroplating" and "polishing" on the surface of the AMB ceramic copper clad substrate, thereby improving the bonding strength between the AMB ceramic copper clad substrate and the chip, and the bonding performance is more firm. 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 the AMB ceramic copper-clad substrate to three-step improvement treatments of grinding, copper plating and polishing, then etching a precision circuit diagram on the surface, and finally attaching a silver film and a chip on the surface in sequence and heating and curing them respectively.

[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 subjected to copper plating;

[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 turn and heated and cured respectively to obtain a precise AMB ceramic circuit board.

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

[0015] The copper foil thickness of the AMB ceramic copper-clad substrate is reduced by mechanical grinding to facilitate subsequent copper plating, so as to 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 performed 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 and dried with hot water at 50 to 60° C. to complete the copper electroplating.

[0018] Furthermore, the specific process of degreasing is: putting 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: putting the degreased AMB ceramic copper-clad substrate into 2-4wt% concentrated sulfuric acid, soaking for 1-2 minutes, taking it out, washing it twice with overflow water, and completing 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, to obtain an ethanol solution of 5-bromo-2,2'-bipyridine; (2) adding a fatty alcohol ethoxylate to water, stirring and dissolving, to obtain 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, wherein 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 be used as a non-ionic surfactant to reduce the surface tension of the electroplating solution, thereby improving the hole-filling capacity of the electroplating solution and making the coating crystallization 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 dropping the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine therein, 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 into the electroplating solution can promote electroplating, thereby facilitating the formation of a coating with a dense surface and good bonding strength. It can cooperate with additive I to promote copper electroplating, so that the bonding strength and surface quality of the copper foil surface reach an ideal state.

[0028] Furthermore, the parameters of the electroplating treatment 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 coating thickness is 25 to 50 μm.

[0029] The thickness of the copper foil ground off above 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 3000 to 4000 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 conventional 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. The present invention solves the difficult problems that the traditional AMB ceramic copper-clad substrate and the chip are easily offset, loosely bonded, and easy to slip during attachment;

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

[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 steps of improvement: grinding, copper plating, and polishing. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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.

[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 embodiments, a double-sided copper-clad AMB ceramic copper-clad substrate is selected for improvement treatment. The theoretical thickness of the 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, stir and 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, stir and 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, add 400 mL of 50 wt% ethanol solution, and 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 to 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 to dissolve, and then slowly drop the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine therein, stir and mix for 1.5 hours, collect the filtrate by filtration, let stand for 72 hours, collect the crystals, and 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 31 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.885 mm.

[0051] S2: Copper plating:

[0052] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0053] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 19 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.887 mm.

[0064] S2: Copper plating:

[0065] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0066] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 22 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.889 mm.

[0077] S2: Copper plating:

[0078] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0079] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 33 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.881 mm.

[0090] S2: Copper plating:

[0091] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0092] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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: Brush treatment:

[0097] After the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 25 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.894 mm.

[0103] S2: Copper plating:

[0104] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0105] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thickness was 30 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.887 mm.

[0116] S2: Copper plating:

[0117] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0118] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 25 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.896 mm.

[0131] S2: Copper plating:

[0132] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0133] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thickness was 30 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.893 mm.

[0145] S2: Copper plating:

[0146] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0147] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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 the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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 ceramic copper-clad substrate was mechanically ground by ceramic brush 1 and ceramic brush 2 of the brushing machine. The parameters of mechanical grinding were as follows: grinding speed was 0.9 m / min, current of ceramic brush 1 was 1 A, current of ceramic brush 2 was 0.35 A, grinding thinning thickness was 29 μm, and the average thickness of the AMB ceramic copper-clad substrate after grinding was 1.889 mm.

[0159] S2: Copper plating:

[0160] (1) The ground AMB ceramic copper-clad substrate was placed in a TD-121 acid degreasing agent, soaked at 55°C for 2.5 minutes, taken out, washed with hot water at 55°C, and then washed twice with overflow water to complete the degreasing;

[0161] (2) placing the degreased AMB ceramic copper-clad substrate in 3 wt % concentrated sulfuric acid for 1.5 min, taking it out, and washing it 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 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 treatment 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: Brush treatment:

[0166] After the electroplating treatment, the AMB ceramic copper-clad substrate is polished by nylon brush 1 and nylon brush 2 of the brushing machine; the parameters of the polishing are: the polishing speed is 1.1m / min, the current of nylon brush 1 is 1.1A, and the current of nylon brush 2 is 1A;

[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 turn 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-mentioned 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, as shown in Tables 2 to 5 below:

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

[0173] Hot and cold shock: Heat the AMB ceramic copper-clad substrate at 355°C for 130 seconds, then cool it at 25°C for 45 seconds. This is one cycle, and repeat 15 times to observe whether the copper clad layer falls off or other abnormal conditions occur.

[0174] Table 2 Roughness comparison

[0175]

[0176] Table 3 Comparison of hitting 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 additives I and II play an important role in copper electroplating;

[0185] The following is only a comparison of the relevant test results of the embodiments, 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) Hardness: The AMB ceramic copper-clad substrate after grinding, electroplating and polishing has a higher hardness. avg =78.94Gpa>46.56Gpa;

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

[0190] In summary, after vacuum brazing of conventional AMB ceramic copper-clad substrates, irregular grains will naturally appear on the surface of the copper foil. The grains are rough and poor in density, and the chip will shift to varying degrees, have loose bonding, or even fall off during the subsequent chip attachment process. However, the present invention takes a new approach, using a three-step improvement method of "grinding + copper plating + polishing" on the surface of the copper foil sintered by the traditional AMB process to change the morphology of the copper foil, making the surface free of grains and smooth and dense, and having a higher bonding strength with the chip, solving the problems of chip shift, loose bonding, and falling off. 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 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 method for preparing a precision AMB ceramic circuit board, characterized in that: The following steps are involved: S1: grinding the AMB ceramic copper-clad substrate; S2: After S1, the AMB ceramic copper-clad substrate is subjected to copper plating; 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 turn and heated and cured respectively to obtain a precise AMB ceramic circuit board.

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

3. The method for preparing a precision AMB ceramic circuit board according to claim 1, characterized in that: The copper plating is carried out by electroplating, and the specific process is: firstly, the ground AMB ceramic copper-clad substrate is degreased and activated in sequence, then placed in an electroplating solution for electroplating, and finally washed and dried with hot water at 50 to 60° C. to complete the copper plating.

4. The method for preparing a precision AMB ceramic circuit board according to claim 3, characterized in that: The electroplating solution comprises the following concentration components: 80-120 g / L of copper sulfate, 100-140 mL / L of concentrated sulfuric acid, 60-100 ppm of chloride ions, 5-15 mL / L of additive I, 0.2-0.4 g / L of additive II, and the solvent is deionized water.

5. The method for preparing a precision AMB ceramic circuit board according to claim 4, characterized in that: The preparation method of the additive I is as follows: (1) adding 5-bromo-2,2'-bipyridine to anhydrous ethanol, stirring and dissolving, to obtain an ethanol solution of 5-bromo-2,2'-bipyridine; (2) adding a fatty alcohol ethoxylate to water, stirring and dissolving, to obtain 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, adding 50wt% ethanol solution to the fixed volume, to obtain the additive I; The additive I comprises the following concentration components: 8-16 g / L 5-bromo-2,2'-bipyridine, 24-48 g / L fatty alcohol ethoxylate, and the solvent is a 50 wt% ethanol solution.

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

3.

7. The method for preparing a precision AMB ceramic circuit board according to claim 4, characterized in that: 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 dropping the dichloromethane solution of 4'-(3-pyridyl)-2,2':6',2"-terpyridine therein, 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 the additive II; The mass ratio of the 4'-(3-pyridyl)-2,2':6',2"-terpyridine to cerium nitrate is 2:

1.

8. The method for preparing a precision AMB ceramic circuit board according to claim 3, characterized in that: The parameters of the electroplating treatment 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 coating thickness is 25 to 50 μm.

9. The method for preparing a precision AMB ceramic circuit board according to claim 1, characterized in that: The specific polishing brushing is as follows: after copper plating, the AMB ceramic copper-clad substrate is polished by the non-woven brush 1 and the non-woven brush 2 of the brush machine in turn; the parameters of the polishing brushing 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. 10 . 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 9 .

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