CN114007335A

CN114007335A - Production method of AMB ceramic copper-clad plate

Info

Publication number: CN114007335A
Application number: CN202111085674.2A
Authority: CN
Inventors: 黎铭坚
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-16
Filing date: 2021-09-16
Publication date: 2022-02-01

Abstract

The invention belongs to the technical field of ceramic-metal composite material manufacturing, and particularly relates to a method for preparing an AMB ceramic copper-clad plate based on a cold spraying process, which comprises the following steps: carrying out ultrasonic cleaning, drying and sand blasting treatment on the ceramic substrate; carrying out cold spraying on the AMB active brazing filler metal powder by taking inert gas as a medium, and spraying an active brazing filler metal coating on the ceramic substrate; carrying out cold spraying on high-purity copper powder by taking inert gas as a pneumatic medium, and superposing and spraying a copper conductive coating on the active solder coating; placing the composite coating ceramic plate in a vacuum brazing furnace for high-temperature brazing so as to realize full brazing fusion among the ceramic substrate, the active brazing filler metal coating and the copper coating; thinning the surface of the ceramic copper-clad plate until a set coating thickness and surface roughness meeting the process requirement are obtained; and printing a circuit diagram on the surface of the copper clad laminate, manufacturing a circuit board by adopting a wet etching process, and preparing the AMB ceramic copper clad laminate product by a surface plating process.

Description

Production method of AMB ceramic copper-clad plate

Technical Field

The invention belongs to the technical field of ceramic-Metal composite material manufacturing, and particularly relates to a preparation method of an Active Metal Bonding (AMB) ceramic copper-clad plate based on a cold spraying process.

Background

In the third generation semiconductor device design, the chip size is required to be smaller and smaller, and the device is required to meet the application requirements of high frequency, high temperature and high power. The reduction of chip size means a sharp increase in power density, and in order to realize high-density three-dimensional modular packaging of high-power electronic devices, new requirements for reliability of modular heat dissipation packaging are made. High-voltage high-power modules represented by IGBT (insulated gate bipolar transistor) power modules are widely used in strategic industries such as rail transit, aerospace, new energy vehicles, wind power generation, national defense industry and the like. The fields need to use high-quality ceramic copper-clad platesTo have Al₂O₃AlN or Si₃N₄Several ceramic substrates. Especially Si₃N₄And the AlN ceramic can quickly dissipate the heat of the power module block to the outside due to high strength and high heat dissipation, so that the AlN ceramic becomes the best packaging material of the IGBT power module in the field of power electronics. Therefore, it is common knowledge in the industry to develop a ceramic copper-clad substrate with higher reliability, better temperature resistance and stronger current-carrying capacity.

In two main production processes of ceramic surface metallization, a direct copper-clad ceramic substrate (DCB) directly coats copper on ceramic by using oxygen-containing eutectic liquid of the copper; active Metal brazing copper-clad ceramic substrates (AMB) are reaction layers which can be wetted by liquid brazing filler Metal and are generated by chemical reaction of a small amount of Active elements contained in the brazing filler Metal and the ceramic at high temperature, and therefore high Bonding strength between the ceramic and the Metal is achieved. Compared with the two, the active metal brazing copper-clad ceramic substrate has higher comprehensive performance. The active welding process comprises printing paste active metal solder on the surface of ceramic, or adhering active metal foil on the surface of ceramic, clamping with oxygen-free copper, and brazing at high temperature in a vacuum brazing furnace; after the brazing is finished, a circuit is manufactured on the surface of the copper-clad plate by adopting a wet etching process similar to a PCB (printed Circuit Board), and finally, a ceramic copper-clad plate product with reliable performance is prepared by plating metal films such as nickel, gold and the like on the surface. However, in the processing process of the AMB copper clad laminate, since the thermal expansion coefficients of the metal copper and the ceramic material are greatly different, after copper is coated under a high temperature condition, a large additional thermal stress is easily generated in the ceramic substrate. Furthermore, due to the periodic usage characteristics of the electronic package substrate itself, thermal stress may be sequentially generated on the ceramic substrate during frequent temperature rise and temperature fall. Therefore, after long-time use, micro cracks are easy to generate and spread in the substrate, so that the packaging substrate is easy to crack or the copper-clad layer is easy to peel off to fail, and the reliability of the high-power IGBT power module is influenced. Therefore, a new method for stably and effectively combining ceramic and copper and improving the reliability of the copper-clad ceramic substrate in the cold and hot circulation is needed.

Disclosure of Invention

The invention aims to: aiming at the technical problem of the production of the existing AMB ceramic copper-clad plate, the novel production method of the AMB ceramic copper-clad plate based on the cold spraying technology is provided, and the cold spraying technology is innovatively applied to the manufacturing flow of the ceramic copper-clad plate for the first time. Specifically, an ultrasonic rapid cold spraying device is adopted, an active solder layer is sprayed and embedded on a ceramic substrate, pure copper powder is covered and sprayed on an active solder coating, and a copper-clad plate is placed in a vacuum brazing furnace for high-temperature brazing, so that firmer and more reliable interface fusion is formed between the active solder layer and the copper powder, and the process can effectively eliminate the internal stress formed by the spraying process. The copper-clad plate produced by the process has the advantages that the active brazing filler metal coating, the ceramic substrate and the pure copper coating are mutually diffused to realize metallurgical bonding, the coating is compact, and the interface has no defects such as holes, brittle phases and oxidation; the copper-clad plate has stronger current carrying capacity, higher reliability and better cold and heat cycle resistance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of an AMB ceramic copper-clad plate based on a cold spraying process at least comprises the following steps:

step one, carrying out ultrasonic cleaning, drying and sand blasting treatment on a ceramic substrate to obtain a clean substrate surface with a concave-convex surface as an interface for embedding an active solder;

secondly, inputting AMB active brazing filler metal powder into a powder feeding system of a cold spraying system, and carrying out cold spraying by using inert gas as a pneumatic medium to form an active brazing filler metal coating on the ceramic substrate; when the powder feeding system works, the AMB active brazing filler metal powder on the powder feeding system is accelerated by the airflow sprayed by the spray gun and then collides with the ceramic substrate at a high speed, so that powder particles are subjected to plastic deformation and are embedded and deposited on the surface of the ceramic substrate.

Inputting pure copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using inert gas as a spraying medium, and spraying a copper coating on the active solder coating obtained in the step two in a superposed manner; when the powder feeding system works, pure copper powder in the powder feeding system is accelerated by airflow sprayed by the spray gun and then collides with the active brazing filler metal coating at a high speed to cover the surface of the active brazing filler metal to form a composite coating.

Fourthly, placing the composite coating ceramic plate obtained in the third step in a vacuum brazing furnace for high-temperature welding so as to realize full brazing fusion among the ceramic substrate, the active brazing filler metal coating and the copper coating and obtain a ceramic copper-clad plate;

step five, grinding or electrochemically thinning the surface of the ceramic copper-clad plate obtained in the step four until the thickness and the surface roughness of the required copper coating are obtained;

and step six, printing a circuit diagram on the surface of the copper-clad plate obtained in the step five, then manufacturing a circuit board on the surface of the copper-clad plate by adopting a wet etching process similar to a PCB (printed Circuit Board), and then preparing the ceramic copper-clad plate product with reliable performance through process flows such as plating nickel, gold and other metal films on the surface.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the ceramic substrate in the step one is made of Al₂O₃AlN or Si₃N₄(ii) a The materials used for the sand blasting treatment are diamond, boron carbide or cubic boron nitride, the hardness of the three materials is higher than that of the ceramic substrate, and the purpose of roughening the surface of the substrate can be realized; the granularity of the sand blasting is 16-30 meshes.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the AMB active brazing filler metal powder used In the second step is AgCuTi high-temperature brazing filler metal, the typical component of the brazing filler metal powder is AgCuTiX, wherein the AgCu content accounts for more than 90% by weight, the Ti content accounts for 0.5-8% by weight, the X component is at least one of In, Zr, Sn, Zn, Cd and Ni, and the sum of the mass fraction ratios of the X component and the Ti component is 0-10%. The AMB active brazing filler metal powder can be completely alloyed powder or can be formed by mixing the component metal powder according to the formula proportion. The metal component powder also comprises compound powder which is decomposed under subsequent high-temperature process conditions to generate corresponding metal simple substances, such as TiH2, ZrH2 and the like. The particle size distribution range of the AMB active brazing filler metal powder is 0.1-53 mu m, and the oxygen content of the powder is less than 200 ppm.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the cold spraying system in the second step and the third step comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun, wherein the spray gun adopts a Laval spray gun, the cold spraying medium gas is high-purity argon or helium, the gas pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is room temperature-750 ℃, and the powder conveying capacity is 0.1-200 g/min; when the spraying gun works, the spraying gun is arranged on the mechanical arm and moves while spraying according to a pre-designed path, and the thickness of the single-layer coating can be adjusted and controlled within the range of 20-100 mu m.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the thickness of the active brazing filler metal coating in the step two is controlled within the range of 20-80 mu m.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the copper powder used in the step three is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, the particle size distribution range of the copper powder is 5-53 microns, the conductivity of the copper conducting layer formed after cold spraying is greater than 99.5 percent IACS, the conductivity of the copper conducting layer is close to that of a copper foil strip, and the technical requirement of the copper-clad plate conducting layer is met.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the ceramic copper-clad plate can be coated with copper on one side or coated with copper on two sides to prepare a double-sided copper-clad plate.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the vacuum degree of high-temperature welding in the fourth step is 10^-2-10^-4Pa, the brazing temperature is 850-1000 ℃, and the heat preservation time is 10-60min, so that the interface brazing among the ceramic substrate, the active brazing filler metal coating and the copper coating is realized under the condition.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the thickness of the pure copper coating required in the fifth step is 50-3000 mu m.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the surface of the ceramic copper-clad plate is thinned by adopting mechanical grinding or electrochemical method until the thickness of the copper coating and the surface roughness meeting the process requirement are obtained, and the roughness Ra is controlled between 0.1 and 0.3.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, in the sixth step, patterns are printed on the surface of the obtained copper-clad plate, and a wet etching process similar to a PCB is adopted to prepare the circuit board.

As an improvement of the preparation method of the AMB ceramic copper-clad plate, the invention also comprises the following steps: and C, enabling the copper-clad plate obtained in the step six and subjected to the wet etching process to enter the next flow in a bare copper state, and also entering the next flow after carrying out nickel plating and gold plating surface treatment.

Compared with the prior art, the invention is a brand-new AMB copper-clad plate production process technology, which abandons the conventional process route that the prior screen printing paste-shaped active metal solder or the active metal soldering lug is attached on a ceramic substrate and then is clamped with oxygen-free copper and then is put into a vacuum brazing furnace for high-temperature brazing, and adopts an 'ultrasonic rapid cold spraying' technology based on the gas dynamics principle. Specifically, the metal powder with a proper particle size is accelerated to supersonic speed and then is impacted on the surface of the ceramic substrate, the powder is embedded on the substrate in a plastic deformation mode and is polymerized to form a coating, and the process is similar to the plastic deformation and cold welding. Firstly spraying an active brazing filler metal layer with the thickness of 20-80 mu m, then covering and spraying pure copper powder on the active brazing filler metal layer to form a compact pure copper coating, and controlling the thickness of the pure copper coating to be 50-3000 mu m; placing the composite ceramic plate obtained after spraying in a vacuum brazing furnace for high-temperature welding to realize full brazing fusion among the ceramic, the active brazing filler metal and the copper; carrying out surface grinding or electrochemical thinning on the copper-clad plate after brazing is finished until the set copper coating thickness is obtained, and simultaneously enabling the surface roughness of the copper coating to meet the design requirement; printing patterns on the copper clad laminate by adopting photosensitive ink, manufacturing a circuit on the surface by adopting a wet etching process similar to a PCB (printed Circuit Board), and finally carrying out surface treatment such as nickel plating, gold plating and the like on the surface of the copper clad laminate to prepare the AMB ceramic copper clad laminate product. The process directly avoids the process path which has the greatest technical difficulty and is easy to cause product stability fluctuation in the production of the AMB copper-clad plate at present, realizes compact and reliable combination between the ceramic substrate and the copper conductor layer, reduces the condition that the substrate fails due to warping of the metal layer at the interface, greatly improves the cold-hot circulation reliability of the copper-clad plate, and has obvious advantages in the aspects of current bearing capacity, heat dissipation capacity, mechanical property, cold-hot circulation reliability and the like. Particularly, when the invention is applied to a silicon nitride ceramic copper-clad plate used in the field of high-power IGBT modules, a cold spraying process can conveniently spray a copper conductive coating with any thickness on a ceramic substrate, and the limit that a copper foil layer cannot be too thick (the thickness of the copper foil layer is generally not more than 1.2 mm, and the thicker the copper foil is, the more serious the warping problem caused by thermal stress) is not limited under the process condition of the existing copper-clad plate. The ceramic copper-clad plate has very wide application prospect in the fields of high-speed rails, high-power LEDs, electric automobiles, 5G communication modules and the like. Therefore, the invention has important industrial application value.

Detailed Description

The technical solutions of the present invention are described below with specific examples, but the scope of the present invention is not limited thereto.

Example 1

The embodiment provides a preparation method of an AMB ceramic copper-clad plate based on a cold spraying process, which at least comprises the following steps:

firstly, ultrasonically cleaning and drying a commercial daily-produced AlN ceramic standard substrate, and sandblasting the ceramic surface by using boron carbide particles with the granularity of 16-30 meshes to obtain a clean substrate surface with a certain concave-convex surface as an interface for embedding an active solder.

And step two, inputting AgCuTi4.5 active solder powder into a powder feeding system of cold spraying equipment, wherein the AgCuTi4.5 powder is produced by an inert gas atomization method, the particle size distribution range is 5-53 microns, the sphericity is more than 80%, and the oxygen content of the powder is less than 200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity argon, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 150 ℃, and the powder conveying capacity is 150-200 g/min; when the device works, the spray gun is arranged on the mechanical arm, the spray gun moves while spraying according to a pre-designed path, a relatively uniform active solder coating can be obtained on the AlN ceramic substrate, and the spraying process condition is controlled to ensure that the thickness of the active solder coating is 30-50 mu m.

And step three, inputting high-purity copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity argon gas as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 5-53 mu m, and the preferred particle size range is 8-38 mu m. And controlling the cold spraying process condition to ensure that the thickness of the obtained copper coating is 850-900 mu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has certain difference, and the thickness error is within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three in a vacuum brazing furnace for high-temperature welding with the vacuum degree of 10^-3-10^-4Pa, controlling the brazing temperature to 950 ℃, and keeping the temperature for 50min, so as to realize interface fusion between the AlN ceramic substrate, the active solder coating and the copper coating under the condition.

And step five, grinding and thinning the surface of the ceramic copper clad laminate obtained in the step four by using a grinding machine until the thickness of the obtained copper coating is 800 microns, and controlling the surface roughness Ra to be 0.3.

And step six, printing patterns on the surface of the copper-clad plate obtained in the step five, and manufacturing the circuit board on the surface of the AlN ceramic copper-clad plate according to the design by adopting a wet etching process similar to a PCB (printed Circuit Board).

The AlN ceramic copper-clad plate has better comprehensive performance, and the optimized copper-clad plate sample has the peel strength of more than 190N/cm and the solder wettability of 100 percent; the thermal cycle is 1200 times without cracks (-40 ℃ to +150 ℃).

Example 2

step one, commercially available German product Si₃N₄And ultrasonically cleaning and drying the standard ceramic substrate, and sandblasting the ceramic surface by using boron carbide particles with the granularity of 16-30 meshes to obtain a clean substrate surface with certain concave-convex surface as an interface for embedding the active brazing filler metal with the substrate surface.

Step two, inputting AgCuTi4.5 active solder powder into a powder feeding system of cold spraying equipment, wherein the AgCuTi4.5 powder is produced by an inert gas atomization method, the particle size distribution range of the AgCuTi4.5 powder is 5-38 microns, and the sphericity of the AgCuTi4.5 powder is higher than that of the powder>80% oxygen content of the powder<200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity helium, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 350 ℃, and the powder conveying capacity is 150-200 g/min; during operation, the spray gun is arranged on the mechanical arm and moves while spraying according to a pre-designed path, and Si₃N₄Relatively uniform active solder coating can be obtained on the ceramic substrate, and the spraying process condition is controlled to ensure that the thickness of the active solder coating is 40-60 mu m.

And step three, inputting high-purity copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity helium as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 150ppm, and the particle size distribution range of the copper powder is 10-38 mu m. And controlling the cold spraying process condition to enable the thickness of the obtained copper coating to be 1250- & lt 1300 & gtmu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has a certain difference, and the thickness error is within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three into a vacuum brazing furnace for high-temperature welding, wherein the vacuum degree in the furnace is 10^-3-10^-4Pa, the brazing temperature is 930 ℃, the heat preservation time is 60min, and Si can be realized under the condition₃N₄The interface between the ceramic substrate, the active solder coating and the copper coating is fused.

And step five, grinding and thinning the surface of the ceramic copper clad laminate obtained in the step four by using a grinding machine until the thickness of the set copper coating is 1200 mu m, and the surface roughness Ra of the copper clad laminate is 0.3.

Step six, printing patterns on the surface of the copper clad laminate obtained in the step five, and adopting a wet etching process similar to a PCB (printed Circuit Board) to perform etching on Si₃N₄And manufacturing a circuit board on the surface of the ceramic copper-clad plate according to the design.

The Si is₃N₄The ceramic copper clad laminate has good comprehensive performance, the optimized copper clad laminate sample has the current carrying capacity of 280-350A and the solder wettability of 100 percent; the reliability test (thermal cycle of (-40 ℃ to +150 ℃) is more than 5200 times without cracks and warps.

Example 3

step one, carrying out commercial domestic Al₂O₃And ultrasonically cleaning and drying the standard ceramic substrate, and sandblasting the ceramic surface by using boron carbide particles with the granularity of 16-30 meshes to obtain a clean substrate surface with certain concave-convex surface as an interface for embedding the active brazing filler metal with the substrate surface.

Step two, inputting AgCuTi2.5 active solder powder into a powder feeding system of cold spraying equipment, wherein the AgCuTi2.5 powder is produced by an inert gas atomization method, the particle size distribution range of the AgCuTi2.5 powder is 5-38 mu m, and the sphericity of the AgCuTi2.5 powder is>80% oxygen content of the powder<200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source and a gas regulation control system for regulating the pressure of gas sent out by the high-pressure gas sourceAnd a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity argon, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 350 ℃, and the powder conveying capacity is 150-200 g/min; during operation, the spray gun is arranged on the mechanical arm, and moves while spraying according to a pre-designed path, Al₂O₃Relatively uniform active solder coating can be obtained on the ceramic substrate, and the spraying process condition is controlled to ensure that the thickness of the active solder coating is 40-60 mu m.

And step three, inputting pure copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity argon as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 8-25 mu m. And controlling the cold spraying process condition to ensure that the thickness of the obtained copper coating is 700-750 mu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has certain difference, and the thickness error is within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three in a vacuum brazing furnace for high-temperature welding with the vacuum degree of 10^-3-10^-4Pa, the brazing temperature is 950 ℃, the heat preservation time is 60min, and Al is realized under the condition₂O₃The interface between the ceramic substrate, the active solder coating and the copper coating is fused.

And step five, grinding and thinning the surface of the ceramic copper-clad plate obtained in the step four by using a grinding machine until the thickness of the copper coating is 700 mu m, and controlling the surface roughness Ra of the copper coating to be 0.3.

Step six, printing patterns on the surface of the copper clad laminate obtained in the step five, and performing wet etching process on the Al by adopting a process similar to the wet etching process of the PCB₂O₃And manufacturing a circuit board on the surface of the ceramic copper-clad plate according to the design.

The Al₂O₃The solder wettability of the optimized sample of the ceramic copper-clad plate is 100 percent; reliability test (-40- +150 ℃ thermal cycle)>350 times.

Example 4

step one, commercially available German product Si₃N₄And ultrasonically cleaning and drying the standard ceramic substrate, and sandblasting the ceramic surface by using diamond particles with the granularity of 16-30 meshes to obtain a clean substrate surface with certain concave-convex surface as an interface for embedding the active brazing filler metal with the substrate surface.

Step two, inputting AgCuTi3.5In0.5 active solder powder into a powder feeding system of cold spraying equipment, wherein the AgCuTi3.5In0.5 powder is produced by an inert gas atomization method, the particle size distribution range is 5-38 microns, and the sphericity is>80% oxygen content of the powder<200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity helium, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 350 ℃, and the powder conveying capacity is 150-200 g/min; during operation, the spray gun is arranged on the mechanical arm and moves while spraying according to a pre-designed path, and Si₃N₄Relatively uniform active solder coating can be obtained on the ceramic substrate, the spraying process condition is adjusted, and the thickness of the active solder coating is controlled to be 40-50 mu m.

And step three, inputting pure copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity helium as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 5-38 mu m. And controlling the cold spraying process condition to enable the thickness of the obtained copper coating to be 1050-.

Step four, the stepThirdly, the obtained composite coating ceramic plate is placed in a vacuum brazing furnace for high-temperature welding with the vacuum degree of 10^-3-10^-4Pa, the brazing temperature is 950 ℃, the heat preservation time is 50min, and Si is realized under the condition₃N₄The interface between the ceramic substrate, the active solder coating and the copper coating is fused.

And step five, grinding and thinning the surface of the ceramic copper clad laminate obtained in the step four by using a grinding machine until the thickness of the set copper coating is 1000 microns, and controlling the surface roughness Ra to be 0.3.

Step six, printing patterns on the surface of the copper clad laminate obtained in the step five, adopting a wet etching process similar to a PCB (printed Circuit Board), and carrying out Si etching₃N₄And manufacturing a circuit board on the surface of the ceramic copper clad laminate according to the design, and then carrying out nickel plating treatment on the copper clad laminate.

Example 5

firstly, ultrasonically cleaning and drying a commercial daily-produced AlN ceramic standard substrate, and sandblasting the ceramic surface by using cubic boron nitride particles with the granularity of 16-30 meshes to obtain a clean substrate surface with certain concave-convex surfaces as an interface for embedding an active solder.

And step two, inputting AgCuTi5.5Sn0.3 active brazing filler metal powder into a powder feeding system of cold spraying equipment, wherein the AgCuTi5.5Sn0.3 powder is produced by an inert gas atomization method, the particle size distribution range is 5-38 microns, the sphericity is more than 80%, and the oxygen content of the powder is less than 200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity helium, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 350 ℃, and the powder conveying capacity is 150-200 g/min; when the device works, the spray gun is arranged on the mechanical arm, the spray gun moves while spraying according to a pre-designed path, a relatively uniform active solder coating can be obtained on the AlN ceramic substrate, and the spraying process condition is controlled to ensure that the thickness of the active solder coating is 20-40 mu m.

And step three, inputting pure copper powder into a powder feeding system of a cold spraying system, performing cold spraying by using helium as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 10-38 mu m. And controlling the cold spraying process condition to ensure that the thickness of the obtained copper coating is 900-920 mu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has certain difference, and the thickness error is within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three in a vacuum brazing furnace for high-temperature welding with the vacuum degree of 10^-3-10^-4Pa, the brazing temperature is 920 ℃, the heat preservation time is 45min, and the interface fusion among the AlN ceramic substrate, the active brazing filler metal coating and the copper coating is realized under the condition.

And step six, printing patterns on the surface of the copper clad laminate obtained in the step five, manufacturing a circuit board on the surface of the AlN ceramic copper clad laminate according to the design by adopting a wet etching process similar to a PCB, and then performing gold plating treatment on the copper clad laminate.

Example 6

step one, the commercial daily Si is put into₃N₄And ultrasonically cleaning and drying the standard ceramic substrate, and sandblasting the ceramic surface by using boron carbide particles with the granularity of 16-30 meshes to obtain a clean substrate surface with certain concave-convex surface as an interface for embedding the active brazing filler metal with the substrate surface.

Step two, inputting AgCuTi2.5Zr1.2 active solder powder into cold sprayingThe powder feeding system of the device is produced by an AgCuTi2.5Zr1.2 powder system inert gas atomization method, the particle size distribution range of the powder is 2-25 microns, and the sphericity of the powder is>80% oxygen content of the powder<200 ppm. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity argon, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 250 ℃, and the powder conveying capacity is 150-200 g/min; during operation, the spray gun is arranged on the mechanical arm and moves while spraying according to a pre-designed path, and Si₃N₄Relatively uniform active solder coating can be obtained on the ceramic substrate, and the spraying process condition is controlled to ensure that the thickness of the active solder coating is 40-50 mu m.

And step three, inputting pure copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity argon as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 150ppm, and the particle size distribution range of the copper powder is 10-38 mu m. The cold spraying process condition is controlled to ensure that the thickness of the obtained copper coating is 1850-1900 mu m (at the moment, the thickness of the copper coating at each position on the copper-clad plate has certain difference, and the thickness error is within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three into a vacuum brazing furnace for high-temperature welding, wherein the vacuum degree in the furnace is 10^-3-10^-4Pa, the brazing temperature is 910 ℃, the heat preservation time is 55min, and Si can be realized under the condition₃N₄The interface between the ceramic substrate, the active solder coating and the copper coating is fused.

And step five, grinding and thinning the surface of the ceramic copper clad laminate obtained in the step four by using a grinding machine until the thickness of the set copper coating is 1800 mu m, and controlling the surface roughness Ra to be 0.3.

Step six, obtained in step fivePrinting patterns on the surface of the copper clad laminate, and adopting a wet etching process similar to a PCB (printed Circuit Board) to perform Si etching₃N₄And manufacturing a circuit board on the surface of the ceramic copper-clad plate according to the design.

Example 7

Step two, taking AgCu28 alloy powder meeting the requirements and pure Ti powder according to the mass percentage of AgCu 28: after Ti =96:4 is fully and uniformly mixed, the mixed powder is input into a powder feeding system of cold spraying equipment; wherein the AgCu28 powder is produced by inert gas atomization method, the particle size distribution range is 5-38 microns, and the sphericity is>80% oxygen content of the powder<200 ppm; pure Ti powder is spherical powder produced by plasma spraying method, and has particle size distribution range of 5-38 μm, oxygen content<500ppm, sphericity>95 percent. The cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity helium, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 350-450 ℃, and the powder conveying capacity is 150-200 g/min; during operation, the spray gun is mounted on a mechanical arm, moves while spraying according to a pre-designed path, and sprays on Si₃N₄A relatively uniform active solder coating is obtained on the surface of the ceramic substrate, which is embedded on the rough surface of the ceramic substrate. The spraying process condition is controlled, so that the thickness of the active solder coating is 30-40 mu m.

And step three, inputting high-purity copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity argon as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 10-38 mu m. The cold spraying process condition is controlled to enable the thickness of the obtained copper coating to be 1250-1280 mu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has a certain difference, and the thickness error is generally within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three into a vacuum brazing furnace for high-temperature welding, wherein the vacuum degree in the furnace is 10^-3-10^-4Pa, the brazing temperature is 930 ℃, the heat preservation time is 60min, and Si can be realized under the condition₃N₄The interface between the ceramic substrate, the active solder coating and the copper coating is fused. After brazing, metallurgical-grade bonding is realized between the active brazing filler metal layer and the ceramic substrate as well as between the active brazing filler metal layer and the copper coating, no defects such as cavities and slag inclusion exist on the interface, and the density of the pure copper layer is high>99.5%。

And step five, grinding and thinning the copper coating surface of the ceramic copper-clad plate obtained in the step four by using a grinding machine until the set copper coating thickness is 1200 mu m, and controlling the surface roughness Ra to be 0.3.

Step six, printing patterns on the surface of the copper clad laminate obtained in the step five, and adopting a wet etching process similar to a PCB (printed Circuit Board) to perform etching on Si₃N₄And manufacturing the circuit board on the surface of the ceramic copper-clad plate according to the design pattern.

The Si is₃N₄The ceramic copper clad laminate has excellent comprehensive performance, and the optimized copper clad laminate sample has the current carrying capacity of 280-350A and the solder wettability of 100 percent; the reliability test (thermal cycle of (-40 ℃ to +150 ℃) is more than 5000 times, no crack exists, and the copper coating does not warp. The Si is₃N₄And carrying out a subsequent surface gold plating process on the ceramic copper-clad plate to obtain a finished product of the copper-clad plate.

Example 8

Firstly, ultrasonically cleaning and drying a commercial domestic AlN ceramic standard substrate, and sandblasting the ceramic surface by using boron carbide particles with the granularity of 16-30 meshes to obtain a clean substrate surface with a certain concave-convex surface as an interface for embedding an active solder.

Step two, taking AgCu28 alloy powder meeting the requirements and TiH2 powder according to the weight percentage of AgCu 28: TiH2=97:3, which are mixed and then ball milled with low intensity, wherein the AgCu28 powder is produced by an inert gas atomization method, the particle size distribution range is 5-38 microns, the sphericity is more than 80%, and the oxygen content of the powder is less than 200 ppm; the TiH2 powder is a chemical pure superfine powder sold in the market, the purity of the TiH2 powder is more than 99.9%, the particle size is 0.1-0.5 micron, and after 24 hours of ball milling and mixing, the fine TiH2 powder is adhered to the surface of the AgCu28 powder to form composite powder. Inputting the AgCu 28-TiH 2 composite powder into a powder feeding system of cold spraying equipment; the cold spraying system comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas adjusting and controlling system for adjusting the pressure of gas sent out by the high-pressure gas source and a spray gun. The spray gun is a Laval spray gun, the cold spraying medium gas is high-purity helium, the spraying pressure is 1.5-3.5 Mpa, the working temperature of the medium gas is 450-; during operation, the spray gun is mounted on a mechanical arm, and moves along a pre-designed path while spraying, so that a relatively uniform active solder coating can be obtained on the surface of the AlN ceramic substrate, and the coating is embedded on the rough surface of the ceramic substrate. Under the condition of spraying process temperature, TiH2 ultrafine powder compounded on the surface of AgCu28 powder is decomposed into simple substance Ti and H2 (H2 is dissipated with inert gas), newly generated Ti particles have extremely high activity, and the newly generated Ti particles are uniformly distributed in a brazing filler metal coating. The spraying process condition is controlled, so that the thickness of the active solder coating is 30-40 mu m.

And step three, inputting pure copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by using high-purity argon as a spraying medium, and spraying a thicker copper coating on the active solder coating obtained in the step two in a superposed manner, wherein cold spraying equipment and cold spraying process conditions adopted in the step three are basically the same as those in the step two. The copper powder used in the process step is spherical powder, the purity is not less than 99.99 percent, the oxygen content is less than 200ppm, and the particle size distribution range of the copper powder is 10-38 mu m. The cold spraying process condition is controlled to ensure that the thickness of the obtained copper coating is 880-900 mu m (at the moment, the thickness of the copper coating at each position point on the copper-clad plate has a certain difference, and the thickness error is generally within 50 mu m).

Step four, placing the composite coating ceramic plate obtained in the step three into a vacuum brazing furnace for high-temperature welding, wherein the vacuum degree in the furnace is 10^-3-10^-4Pa, the brazing temperature is 930 ℃, the heat preservation time is 60min, and the interface fusion among the AlN ceramic substrate, the active brazing filler metal coating and the copper coating can be realized under the condition. After brazing, the active brazing filler metal layer, the ceramic substrate and the copper coating are mutually diffused to realize metallurgical bonding, the interface has no defects of cavities, slag inclusion and the like, and the density of the coating can reach 99.5%.

And step five, grinding and thinning the copper coating surface of the ceramic copper-clad plate obtained in the step four by using a grinding machine until the set copper coating thickness is 800m m, and controlling the surface roughness Ra to be 0.3.

And step six, printing a pattern on the surface of the copper-clad plate obtained in the step five, and manufacturing the circuit board on the surface of the AlN ceramic copper-clad plate according to the design pattern by adopting a wet etching process similar to a PCB (printed Circuit Board).

The AlN ceramic copper-clad plate can be made into a finished product of the copper-clad plate after a subsequent surface gold plating process.

Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and the related alloy element ratio changes within the formula scope of the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A preparation method of an AMB ceramic copper-clad plate is based on a cold spraying process and is characterized by at least comprising the following steps:

secondly, inputting AMB active brazing filler metal powder into a powder feeding system of a cold spraying system, and carrying out cold spraying by taking inert gas as a pneumatic medium to form an active brazing filler metal coating on the ceramic substrate;

inputting high-purity copper powder into a powder feeding system of a cold spraying system, carrying out cold spraying by taking inert gas as a pneumatic medium, and spraying a copper coating on the active solder coating obtained in the step two in a superposed manner;

step four, placing the composite coating ceramic plate obtained in the step three in a vacuum brazing furnace for high-temperature vacuum welding so as to realize full brazing fusion among the ceramic substrate, the active brazing filler metal coating and the copper coating and obtain a ceramic copper-clad plate;

step five, thinning the surface of the ceramic copper-clad plate obtained in the step four until the set thickness of the copper coating and the qualified surface roughness are obtained;

and step six, printing a circuit diagram on the surface of the copper clad plate obtained in the step five by using ink, manufacturing a circuit board by using a wet etching process, and preparing the AMB ceramic copper clad plate product meeting the design requirement by using a surface plating process.

2. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the ceramic substrate in the first step is made of Al₂O₃AlN or Si₃N₄(ii) a The material used for sand blasting is diamond, boron carbide or cubic boron nitride, and the granularity of sand blasting is 16-30 meshes.

3. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the AMB active brazing filler metal powder used In the second step is AgCuTi high-temperature brazing filler metal, the typical component of the AMB active brazing filler metal powder is AgCuTiX, wherein the sum of the contents of Ag and Cu accounts for more than 90% by mass, the content of Ti accounts for 0.5-8% by weight, X In the formula is at least one of V, Zr, Hf, In, Cr, Sn, Zn, Cd, Si, Al and Ni, and the sum of the mass fractions of the element X and the Ti is 0-10%; the particle size distribution range of the AMB active brazing filler metal powder is 0.1-53 mu m, and the oxygen content of the powder is less than 200 ppm.

4. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the cold spraying system in the second step and the third step comprises a powder feeding system, a high-pressure gas source, a gas heater for heating the high-pressure gas source, a gas regulation control system for regulating the pressure of gas sent out by the high-pressure gas source and a spray gun, the spray gun adopts a Laval spray gun, the cold spraying medium gas is high-purity argon or helium, the gas pressure is 1.5-3.5 MPa, the working temperature of the medium gas is room temperature-750 ℃, and the powder conveying capacity is 0.1-300 g/min; when the spraying gun works, the spraying gun is arranged on the mechanical arm, and moves while spraying according to a pre-designed path, so that a coating with the same components as the spraying raw material powder can be obtained on the substrate after spraying.

5. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the thickness of the AMB active brazing filler metal coating required in the step three is 20-80 μm.

6. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the high-purity copper powder used in the step three is spherical powder, the purity is not less than 99.99%, the oxygen content is less than 200ppm, and the diameter distribution range of the pure copper powder particles is 5-53 μm.

7. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the thickness of the copper coating required in the fifth step is 50-3000 μm.

8. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the vacuum degree of the high-temperature welding in the fourth step is 10^-2-10^-4Pa, the brazing temperature is 850-1000 ℃, and the heat preservation time is 10-60min, so that the interface brazing among the ceramic substrate, the active brazing filler metal coating and the copper coating is realized under the condition.

9. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, wherein the thinning in the fifth step is mechanical grinding thinning or electrochemical thinning; the surface roughness Ra of the copper coating after thinning processing is controlled between 0.1 and 0.3.

10. The method for preparing the AMB ceramic copper-clad plate based on the cold spraying process according to claim 1, further comprising the following steps: and (5) carrying out nickel plating or gold plating surface treatment on the copper-clad plate which is obtained in the step six and has completed the wet etching process.