阅读说明：本技术 一种在氮化铝陶瓷表面敷铜或敷铜合金的方法 (Method for coating copper or copper alloy on surface of aluminum nitride ceramic ) 是由 潘伟 刘广华 于 2021-01-21 设计创作，主要内容包括：本申请公开了一种在氮化铝陶瓷表面敷铜或敷铜合金的方法,选用金属铜或铜合金粉体,通过大气等离子喷涂技术将金属铜或铜合金粉体在熔融状态下喷涂在覆盖有特定图案掩模版的氮化铝陶瓷基板表面,调整诸多工艺参数和等离子体喷枪结构制备出铜或铜合金与氮化铝陶瓷界面结合强度高、电导率高的氮化铝陶瓷敷铜基板。本申请直接将金属铜或铜合金粉末喷涂在高导热氮化铝陶瓷基板上得到铜陶瓷基板或者将铜或铜合金粉末喷涂在覆盖有电路图案的掩膜的高导热氮化铝陶瓷基板上,得到不同图案且线宽精度高的敷铜电路陶瓷基板,是一种新的敷铜或铜合金氮化铝陶瓷基板及制备方法,该方法简单,可以实现快速、大面积制备,降低成本,具有广阔的应用前景。(The application discloses a method for coating copper or copper alloy on the surface of aluminum nitride ceramic, wherein metal copper or copper alloy powder is selected, the metal copper or copper alloy powder is sprayed on the surface of an aluminum nitride ceramic substrate covered with a mask plate with a specific pattern in a molten state by an atmospheric plasma spraying technology, and a plurality of process parameters and a plasma spray gun structure are adjusted to prepare the aluminum nitride ceramic copper-coated substrate with high bonding strength and high conductivity between the copper or copper alloy and the aluminum nitride ceramic interface. The copper-clad circuit ceramic substrate with different patterns and high line width precision is obtained by directly spraying metal copper or copper alloy powder on the high-heat-conductivity aluminum nitride ceramic substrate to obtain the copper ceramic substrate or spraying copper or copper alloy powder on the high-heat-conductivity aluminum nitride ceramic substrate covered with a mask of a circuit pattern.)

1. An atmospheric plasma spray gun, the spray gun includes plasma ionization chamber, electrode, cooling gas device and cooling liquid device;

the plasma ionization chamber comprises a plasma nozzle, a powder feeding channel and a plasma gas channel; one end of the powder feeding channel is communicated with the plasma ionization chamber, and the other end of the powder feeding channel is communicated with a powder source; one end of the plasma gas channel is communicated with the plasma ionization chamber, and the other end of the plasma gas channel is communicated with a plasma gas source;

the electrode comprises a positive electrode and a negative electrode, and the positive electrode is arranged on the inner side of the plasma nozzle; the tail end of the negative electrode extends out of the plasma nozzle;

the cooling gas device comprises a cooling gas nozzle and a cooling gas channel, and the cooling gas nozzle surrounding the plasma nozzle is arranged outside the plasma nozzle; one end of the cooling air channel is communicated with the cooling air nozzle, and the other end of the cooling air channel is communicated with a cooling air source;

the cooling liquid device comprises a cooling pipeline and a cooling liquid channel; the cooling pipeline is arranged in the spray gun between the plasma nozzle and the cooling gas nozzle; the cooling liquid channel communicates a cooling liquid source with the cooling pipeline;

the powder is copper or copper alloy.

2. The atmospheric plasma spray torch of claim 1, wherein the cooling line is 2mm to 5mm from a sidewall of the plasma nozzle;

optionally, the plasma nozzle has an orifice diameter of 1.5 to 2 mm.

3. The atmospheric plasma spray gun according to claim 1 or 2, wherein the tip of the negative electrode is circular, and the diameter of the tip of the negative electrode is 0.3 to 2 mm; optionally, the diameter of the end of the negative electrode is 2 mm;

optionally, the length of the cathode extending out of the plasma nozzle is 2mm to 6 mm.

4. A method for coating copper or copper alloy on the surface of aluminum nitride ceramics by using the atmospheric plasma spraying spray gun of any one of claims 1 to 3, wherein the method comprises the steps of coating copper or copper alloy on the aluminum nitride ceramics by using the atmospheric plasma spraying technology in the atmosphere environment;

copper powder or copper alloy powder in the powder source is conveyed to a plasma ionization chamber through the powder feeding channel by carrier gas, and plasma gas in the plasma gas source enters the plasma ionization chamber through the plasma gas channel to form plasma;

and after being melted, the copper powder or the copper alloy powder is sprayed out through the plasma nozzle, and copper or copper alloy is coated on the surface of the aluminum nitride ceramic.

5. The method of claim 4, wherein the cooling gas from the cooling gas nozzle surrounds the plasma beam from the plasma nozzle.

6. The method for coating copper or copper alloy on the surface of aluminum nitride ceramic according to claim 4, wherein the carrier gas, the cooling gas and the plasma gas are inert atmosphere gases;

the inert atmosphere gas is selected from any one or more of inert gas, hydrogen and nitrogen; optionally, the inert atmosphere gas is argon, nitrogen, helium or argon-hydrogen mixed gas;

optionally, the argon-hydrogen mixture has a hydrogen content of 5 vol.% to 15 vol.%; preferably, the content of hydrogen in the argon-hydrogen mixture is 5 vol.% to 10 vol.%.

7. The method of copper or copper alloy cladding on aluminum nitride ceramic surfaces as claimed in any one of claims 4 to 6 wherein the copper alloy is selected from any one or more of nickel alloys of copper, tin alloys of copper, zinc alloys of copper, titanium alloys of copper, silver alloys of copper, lanthanum alloys of copper, samarium alloys of copper, gadolinium alloys of copper, yttrium alloys of copper, neodymium alloys of copper and tungsten alloys of copper;

optionally, the copper or copper alloy powder has a particle size distribution of 1 μm to 100 μm, preferably 1 μm to 30 μm.

8. The method of copper or copper alloy cladding the surface of aluminum nitride ceramic according to any one of claims 4 to 6 wherein said aluminum nitride ceramic is selected from the group consisting of 98 to 99.99 wt.% pure;

optionally, the aluminum nitride ceramic substrate surface roughness is 0.2 μm to 20 μm; preferably, the surface roughness of the aluminum nitride ceramic substrate is 0.3 μm to 20 μm.

9. The method of copper or copper alloy cladding on aluminum nitride ceramic surface as claimed in any of claims 4 to 6 wherein the plasma beam is conical in cross section with a diameter of 0.5mm to 3 mm; optionally, the plasma beam cross section is a circular arc with a diameter of 1 mm.

10. The method for coating copper or copper alloy on the surface of aluminum nitride ceramic according to any one of claims 4 to 6, wherein the step of coating copper or copper alloy on the aluminum nitride ceramic comprises the following steps:

1) fixing the cleaned aluminum nitride ceramic substrate on a platform, and covering a mask plate on the surface to be operated of the aluminum nitride ceramic; optionally, the aluminum nitride ceramic substrate is further cleaned by using a solvent to remove organic matters and impurities on the surface, and the cleaned aluminum nitride ceramic substrate is oxidized for 2-7h at 1050-1250 ℃ in an atmospheric atmosphere;

2) and (3) feeding powder and carrying out atmospheric plasma spraying operation to prepare the copper or copper alloy coated aluminum nitride ceramic circuit board.

11. The method for coating copper or copper alloy on the surface of aluminum nitride ceramic according to claim 10, wherein the thickness of the mask plate is 0.2 mm to 1 mm;

optionally, the material of the mask plate is selected from stainless steel, aluminum alloy, permalloy, copper or copper alloy.

12. The method for coating copper or copper alloy on the surface of aluminum nitride ceramic according to claim 10, wherein in the step 2), the spraying current is 100A to 250A, the spraying distance is 4cm to 10cm, and the moving speed of a spray gun is 50mm/s to 200 mm/s;

optionally, the powder feed rate is from 5 mg/sec to 15 mg/sec, the carrier gas flow rate is from 5l/min to 10 l/min;

alternatively, the number of spraying times is 1 to 10 times depending on the substrate area and the coating thickness requirement, and the spraying time is 10 seconds to 1 minute.

13. The method of claim 10, wherein the spraying operation of step 2) further comprises purging and preheating the aluminum nitride ceramic with plasma, the plasma being generated by plasma gas.

14. The method for copper or copper alloy cladding on the surface of aluminum nitride ceramic according to claim 13, wherein the set current value of the preheating and purging operation is 100A to 300A, and the purging time is 5s to 10 s; preferably, the set current value is 180A, and the purging time is 10s or 5 s;

optionally, the pre-heating temperature of the pre-heating is 200 ℃ to 400 ℃;

optionally, setting the flow rate of plasma gas to be 5 liters/minute to 15 liters/minute during preheating; preferably, the flow rate of the plasma gas is 10 liters/minute.

15. An aluminum nitride ceramic circuit board obtained by the method of applying copper or copper alloy to the surface of an aluminum nitride ceramic according to any one of claims 4 to 14;

optionally, the spray thickness of the copper or copper alloy is 10 μm to 300 μm.

Technical Field

The present invention relates to, but not limited to, aluminum nitride ceramic substrate technology, and more particularly, to, but not limited to, a method for preparing copper and copper alloy clad aluminum nitride ceramic circuit boards and aluminum nitride ceramic metallizing using atmospheric plasma spraying technology.

Background

The aluminum nitride-based material has wide application prospect in the fields of high-heat-conductivity circuit substrates of high-power electronic devices and LEDs and device packaging due to the advantages of high insulativity, high chemical stability, high heat conductivity, thermal expansion coefficient matched with various semiconductor device materials and the like. However, in practical production, the copper or copper alloy coating process of the ceramic substrate is an important factor which limits the application prospect.

The mainstream metallization technology for aluminum nitride substrates subjected to high-temperature oxidation at present is the direct copper plating (DBC) method and the sputtering thin film method (DPC). The sputtering film method requires sputtering a layer of Ti or Zr on the aluminum nitride and then plating copper metal on the aluminum nitride. The sputtering film method has large equipment investment and difficult manufacture, and is difficult to form an industrialized scale. The direct copper plating (DBC) method is that a proper amount of oxygen element is introduced between copper and a ceramic substrate, sintering is carried out at a high temperature of 1065-1083 ℃, and a copper layer is plated on the surface of the ceramic substrate by utilizing oxygen-containing eutectic liquid of copper. However, the temperature control of the method is extremely strict, the copper-clad layer needs to be processed subsequently, and the complex processing technology limits the application of copper-clad or copper alloy ceramic circuit substrates and ceramic metallization.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the present application.

The method aims to replace the traditional high-thermal-conductivity aluminum nitride ceramic copper metallization and copper coating and circuit etching process.

The application provides an atmosphere plasma spraying process for high-thermal-conductivity aluminum nitride ceramic metallization, high-thermal-conductivity aluminum nitride ceramic substrate copper coating and direct preparation of a copper or copper alloy circuit high-thermal-conductivity aluminum nitride ceramic substrate. The preparation method has the advantages of high preparation efficiency, high raw material utilization rate, low price, simple and convenient operation process, high speed, adjustable size range of the sprayed part and capability of completing copper metallization and circuit layer formation in one step. Has great application prospect in the aspects of high heat conduction aluminum nitride ceramic metallization, high heat conduction copper-clad ceramic circuit board substrates and the like.

In the atmospheric plasma spraying technology, the spraying process is carried out in an atmospheric environment, and high-melting-point copper powder or copper alloy powder carried by carrier gas is in a molten state after being sprayed out through a nozzle by the special design of a plasma spray gun nozzle;

the application provides an atmospheric plasma spraying spray gun, which comprises a plasma ionization chamber, an electrode, a cooling gas device and a cooling liquid device;

the plasma ionization chamber comprises a plasma nozzle, a powder feeding channel and a plasma gas channel; one end of the powder feeding channel is communicated with the plasma ionization chamber, and the other end of the powder feeding channel is communicated with a powder source; one end of the plasma gas channel is communicated with the plasma ionization chamber, and the other end of the plasma gas channel is communicated with a plasma gas source; when the selected metal powder is added into the atmospheric plasma spraying equipment, inert gas is adopted for protection;

the electrode arrangement comprises a positive electrode and a negative electrode, and the positive electrode can be regarded as the inner side of the copper nozzle of the plasma gun as the positive electrode; the negative electrode is arranged in the plasma ionization chamber, and the tail end of the negative electrode extends out of the plasma nozzle;

the cooling gas device comprises a cooling gas nozzle and a cooling gas channel, the cooling gas nozzle surrounding the plasma nozzle is arranged outside the plasma nozzle, and the cooling gas sprayed out from the cooling gas nozzle surrounds the plasma beam; one end of the cooling air channel is communicated with the cooling air nozzle, and the other end of the cooling air channel is communicated with a cooling air source;

the cooling liquid device comprises a cooling pipeline and a cooling liquid channel; the cooling pipeline is arranged in the spray gun between the plasma nozzle and the cooling gas nozzle; the cooling liquid channel is used for communicating a cooling liquid source with the cooling pipeline and discharging the cooling liquid in the cooling pipeline out of the spray gun;

the powder is copper or copper alloy.

In one embodiment provided herein, the cooling line is spaced from the sidewall of the plasma nozzle by a distance of 2mm to 5mm, preferably 3 mm;

in one embodiment provided herein, the orifice diameter of the plasma nozzle is 1.5 to 2 mm.

In one embodiment provided herein, the end of the negative electrode is circular, and the diameter of the end of the negative electrode is 0.3 to 2 mm; optionally, the diameter of the end of the negative electrode is 2 mm;

in one embodiment provided herein, the cathode extends beyond the plasma nozzle by a length of 2mm to 6 mm.

In one embodiment provided herein, the negative electrode is made of one or more of tungsten, a tungsten-molybdenum alloy, and a graphite material.

In one embodiment provided herein, the negative electrode may be a circular tungsten electrode for carrying a large current and preventing current instability (as shown in fig. 2) caused by damage of a tungsten electrode tip when melting copper or copper alloy powder under a high current.

On the other hand, the application provides a method for coating copper or copper alloy on the surface of aluminum nitride ceramic, which uses the atmospheric plasma spraying spray gun to realize uniform and precise coating of copper or copper alloy on the surface of aluminum nitride ceramic with high thermal conductivity.

The method comprises the steps of coating copper or copper alloy on aluminum nitride ceramic by using an atmospheric plasma spraying technology in an atmospheric environment;

copper powder or copper alloy powder in the powder source is conveyed to a plasma ionization chamber through the powder feeding channel by carrier gas, and plasma gas in the plasma gas source enters the plasma ionization chamber through the plasma gas channel to form plasma;

and after being melted, the copper powder or the copper alloy powder is sprayed out through the plasma nozzle, and copper or copper alloy is coated on the surface of the aluminum nitride ceramic.

In one embodiment, the cooling gas nozzle sprays cooling gas to surround the plasma beam sprayed by the plasma nozzle.

In one embodiment provided herein, the carrier gas, cooling gas, and plasma gas are inert atmosphere gases;

in one embodiment provided herein, the inert atmosphere gas is selected from any one or more of an inert gas, hydrogen, and nitrogen; optionally, the inert atmosphere gas is argon, nitrogen, helium or argon-hydrogen mixed gas;

in one embodiment provided herein, the argon-hydrogen mixture has a hydrogen content of 5 vol.% to 15 vol.%; preferably, the content of hydrogen in the argon-hydrogen mixture is 5 vol.% to 10 vol.%.

In one embodiment provided herein, the copper alloy is selected from any one or more of a nickel alloy of copper, a tin alloy of copper, a zinc alloy of copper, a titanium alloy of copper, a silver alloy of copper, a lanthanum alloy of copper, a samarium alloy of copper, a gadolinium alloy of copper, a yttrium alloy of copper, a neodymium alloy of copper, and a tungsten alloy of copper;

in one embodiment provided herein, the copper or copper alloy powder has a particle size distribution of from 1 μm to 100 μm, preferably from 1 μm to 30 μm, more preferably from 20 μm to 35 μm.

In one embodiment provided by the application, selected metal copper powder or copper alloy powder is added into an atmosphere plasma spraying device and protected by inert gas;

in one embodiment provided herein, the aluminum nitride ceramic is selected from the group consisting of 98 wt.% to 99.99 wt.% pure; optionally, the aluminum nitride ceramic is selected from one or more of a purity of 99.99 wt.%, 99.90 wt.%, 99.00 wt.%, 98.50 wt.%, and 98.00 wt.%;

the aluminum nitride ceramic may have a thermal conductivity of 170W/m.K to 190W/m.K, a bending strength of 380MPa to 450MPa, and a fracture toughness of 2MPa^1/2To 5 MPa-^1/2The microhardness can be 14 GPa; cleaning, drying, and heating at 1050-1 deg.COxidizing at 250 ℃ and atmospheric pressure for 2-7h to generate a layer of alumina film with the diameter of 1-12 mu m on the surface;

in one embodiment provided herein, the aluminum nitride ceramic substrate has a surface roughness of 0.2 to 20 μm; preferably, the surface roughness of the aluminum nitride ceramic substrate is 0.3-20 μm.

In one embodiment provided herein, the plasma beam is circular in cross-section and 0.5mm to 3mm in diameter; optionally, the plasma beam cross section is a circular arc with a diameter of 1 mm. The atmospheric plasma torch design subjects the plasma arc to three types of compression. These three effects are the mechanical compression effect, the thermal contraction effect and the electromagnetic contraction effect, respectively. Wherein the mechanical compression effect is that the aperture of the mechanical compression water-cooling copper nozzle limits the free expansion of the cross section area of the plasma arc column; the hot compression effect is that cooling water in the nozzle forms a layer of cold air film near the inner wall of the nozzle, further reducing the effective conductive area of the arc column, and further improving the energy density and temperature of the plasma arc column; the electromagnetic compression effect is that due to the two compression effects, the current density of the plasma arc is increased, the electromagnetic shrinkage force generated by the magnetic field of the current of the plasma arc is increased, and the plasma arc is further compressed.

In one embodiment provided herein, the step of applying copper or copper alloy to the aluminum nitride ceramic comprises the following steps:

1) fixing the cleaned aluminum nitride ceramic substrate on a platform, and covering a mask plate on the surface to be operated of the aluminum nitride ceramic; optionally, the aluminum nitride ceramic substrate is further cleaned by using a solvent to remove organic matters and impurities on the surface, and the cleaned aluminum nitride ceramic substrate is oxidized for 2-7h at 1050-1250 ℃ in an atmospheric atmosphere.

2) And (3) feeding powder and carrying out atmospheric plasma spraying operation to prepare the aluminum nitride ceramic circuit board coated with copper or copper alloy in a specific pattern.

In one embodiment, the atmospheric plasma spray process comprises the steps of: turning on a plasma power supply, an air and inert atmosphere gas circuit, condensing water, setting the number of times of preheating the substrate by plasma beam purging, setting plasma beam purging start and end coordinates (X, Y) according to the substrate area size and position, and setting a plasma torch purging movement interval (mm) each time.

In one embodiment provided by the present application, the mask is covered on the aluminum nitride ceramic substrate when spraying a circuit according to the circuit design requirement on the surface of the aluminum nitride ceramic substrate, and the mask may be any pattern; the thickness of the mask is 0.2 mm to 1 mm; optionally, the reticle has a minimum line width of 30 μm.

In one embodiment provided herein, the material of the mask is selected from stainless steel, aluminum alloy, permalloy, copper or copper alloy.

In one embodiment provided by the present application, in step 2), the spraying current in the spraying operation is 100-250A, the spraying distance is 4 cm-10 cm, and the moving speed of the spray gun is 50 mm/s-200 mm/s;

in one embodiment provided herein, the powder feed rate is 5-15 mg/sec (30-60%), the carrier gas flow rate is 5-10 l/min;

in one embodiment provided herein, the number of spray applications is from 1 to 10 depending on the substrate area and coating thickness requirements, with a spray application time from 10 seconds to 1 minute.

In an embodiment provided by the present application, before the spraying operation in step 2), the method further includes purging and preheating the aluminum nitride ceramic by using plasma to remove organic matters and impurities on the surface, and switching to a powder feeding spraying mode after the purging and preheating operation is completed to perform the spraying operation. The plasma is generated from a plasma gas. The plasma is formed by ionization of a plasma gas.

In one embodiment provided by the present application, the set current value of the preheating and purging operation is 100-300A, and the purging time is 5-10 s; preferably, the set current value is 180A, and the purging time is 10s or 5 s;

in one embodiment provided herein, the pre-heating temperature of the pre-heating is 200 ℃ to 400 ℃;

in one embodiment provided herein, the plasma gas flow rate is set at 5-15 liters/minute during preheating; preferably, the flow rate of the plasma gas is 10 liters/minute.

In another aspect, the present application provides an aluminum nitride ceramic circuit board obtained by using the above method for preparing a copper-or copper alloy-coated aluminum nitride ceramic substrate;

in one embodiment provided herein, the copper or copper alloy is sprayed to a thickness of 10 to 300 μm.

In the present application, the spray gun is characterized in that: the light spot of the plasma beam is as small as 1mm, so that the reliability and consistency of the copper layer spraying are ensured; the plasma beam is generated in front of the nozzle, arc striking is not needed, the metal powder is sprayed out through the nozzle by taking inert atmosphere gas (argon, helium, nitrogen or argon-hydrogen mixed gas) as carrier gas, and then the metal powder is heated by the plasma beam at the front end of the nozzle and sprayed onto the aluminum nitride ceramic substrate.

In the present application, the high thermal conductive aluminum nitride ceramic circuit board is prepared to have a room temperature thermal conductivity of 99.39-167.12W (K.m) and a resistivity of 5.2X 10^-3Ω·mm-2.66×10^-3Omega. mm; optionally, the bonding strength of the copper or the copper alloy and the aluminum nitride ceramic substrate is 3.58MPa-17.65 MPa;

in summary, the application provides a copper-clad or copper-clad alloy high-thermal-conductivity aluminum nitride circuit substrate and a preparation method thereof, the method has simple preparation steps and low cost, can be used for mass production, is a method for manufacturing a new copper-clad or high-thermal-conductivity aluminum nitride ceramic substrate or metallizing a high-thermal-conductivity aluminum nitride ceramic substrate, and is expected to replace the traditional technology.

The application is characterized in that: firstly, an aluminum copper nitride metal or copper alloy coating with high bonding strength, excellent electrical property, high thermal conductivity and controllable pattern can be prepared by controllable process condition parameters and special spray gun structure design; secondly, the rapid and large-area preparation can be realized by adopting the atmospheric plasma spraying technology, and the utilization rate of raw materials is high; thirdly, the coating is suitable for spraying of various metal powder and alloy powder, and the coating has excellent performance.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. Other advantages of the present application may be realized and attained by the invention in its aspects as described in the specification.

Drawings

The accompanying drawings are included to provide an understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the examples serve to explain the principles of the disclosure and not to limit the disclosure.

Fig. 1 (a) is an SEM image of the morphology of raw copper powder used in the examples of the present application, and fig. 1 (b) is a particle size distribution of the raw copper powder used in the examples of the present application;

FIG. 2 is a structural view of a plasma torch employed in an embodiment of the present application; reference numerals: 1. a plasma gas inlet, a powder and carrier gas inlet, a tungsten electrode and a cooling pipeline, wherein the plasma gas inlet is 2; 5. a cooling gas outlet; 6. positive electrode region, 7, plasma beam, 8, cooling gas;

FIGS. 3a to 3f are Surface Electron Microscope (SEM) photographs of the high thermal conductive aluminum nitride ceramic substrates as the raw materials used in examples and comparative example 2 of the present application after high temperature oxidation;

FIG. 4 is a cross-Sectional Electron Micrograph (SEM) of a copper-clad aluminum nitride ceramic substrate prepared in comparative example 2 of the present application;

FIG. 5 (a) is an XRD pattern of oxidation peaks of aluminum nitride used in examples of the present application and comparative example 2 after oxidation at different temperatures; FIG. 5 (b) is an XRD pattern of the copper-clad high thermal conductivity aluminum nitride ceramic circuit substrate obtained in the examples of the present application and comparative example 2;

FIG. 6 is a cross-Sectional Electron Microscope (SEM) photograph of a copper-clad high thermal conductivity aluminum nitride ceramic circuit substrate prepared in example 4 of the present application;

fig. 7 shows a high thermal conductivity aluminum nitride copper-clad circuit board with a specific electrode pattern and different line width precision, which is manufactured according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application are described in detail below. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

In the examples of the present application, the aluminum nitride ceramic is an aluminum nitride ceramic having a purity of 98.00 wt.% and having the dimensions: 40mm by 1mm (length, width, thickness). The aluminum nitride ceramic may have a thermal conductivity of 176W/m < K >, a bending strength of 380MPa, and a fracture toughness of 3MPa^1/2The microhardness can be 14 GPa;

in the embodiment of the application, the mask is made of 06Cr19Mi10 stainless steel, the thickness is 0.5mm, and the size is as follows: 40mm by 0.5mm (length, width, thickness).

And after the preheating and blowing operation is finished, switching to a powder feeding spraying mode to perform spraying operation.

In the embodiment of the present application, the atmospheric plasma spraying technique uses one of Micro-Nanoparticle Coater-1700013, CMD-PA60 type atmospheric plasma spraying equipment, SX-80 plasma spraying equipment, AT-300 plasma spraying equipment, Axal III type plasma spraying equipment, Multicoat plasma spraying equipment, GTS plasma spraying equipment, and APS-2000 plasma spraying equipment. The conventional spray gun described in the comparative example was the spray gun included in the plasma spraying apparatus described above.

In the embodiment of the application: the XRD pattern uses an X-ray diffractometer manufactured by Japan science company, model D/max-2500, a Cu Ka 1 target is adopted, the scanning angle 2 theta range is 20-80 degrees, and the scanning speed is 5 degrees/min.

In the embodiment of the application, the used spray gun is an atmosphere plasma spraying spray gun which is used for replacing a spray gun in equipment and comprises a plasma ionization chamber, an electrode, a cooling gas device and a cooling liquid device;

the plasma ionization chamber comprises a plasma nozzle, a powder feeding channel and a plasma gas channel; one end of the powder feeding channel is communicated with the plasma ionization chamber, and the other end of the powder feeding channel is communicated with a powder source; one end of the plasma gas channel is communicated with the plasma ionization chamber, and the other end of the plasma gas channel is communicated with a plasma gas source;

the electrode arrangement comprises a positive electrode and a negative electrode, the positive electrode can be regarded as the inner side of the copper nozzle of the plasma gun to be the positive electrode, and the tail end of the negative electrode extends out of the plasma nozzle;

the cooling gas device comprises a cooling gas nozzle and a cooling gas channel, and the cooling gas nozzle surrounding the plasma nozzle is arranged outside the plasma nozzle; one end of the cooling air channel is communicated with the cooling air nozzle, and the other end of the cooling air channel is communicated with a cooling air source;

the cooling liquid device comprises a cooling pipeline and a cooling liquid channel; the cooling pipeline is arranged in the spray gun between the plasma nozzle and the cooling gas nozzle; the cooling liquid channel is used for communicating a cooling liquid source with the cooling pipeline and discharging the cooling liquid in the cooling pipeline out of the spray gun.

The distance between the cooling pipeline and the side wall of the plasma nozzle is 3 mm; the diameter of the nozzle orifice of the plasma nozzle is 2 mm.

The negative electrode is a tungsten electrode, the tail end of the negative electrode is circular, the length of the negative electrode extending out of the nozzle is 4mm, and the diameter of the tail end of the negative electrode is 2 mm;

example 1

In this example, the apparatus used in the atmospheric plasma spraying technique was Micro-Nanoparticle Coater-1700013.

In this embodiment, the aluminum nitride ceramic circuit board with high thermal conductivity is prepared by applying copper on the surface of aluminum nitride ceramic according to the following steps.

(1) Copper metal powder as shown in b in fig. 1 was added to the atmospheric plasma spray feed system and the argon switch (carrier gas, cooling gas) and plasma gas switch (hydrogen-argon mixture, with a hydrogen content of 7 vol.%) were turned on. And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. Installing a designated tungsten electrode (cathode) and a custom powder plasma torch (as shown in fig. 2) such that a plasma beam is generated between the anode and cathode, a portion of the plasma beam is outside the torch nozzle, the formed plasma beam is compressed into a cone shape with a cross-section of 1 mm;

(2) cleaning an aluminum nitride ceramic substrate with the surface roughness of about 0.3 mu m in alcohol and acetone to remove organic matters and impurities on the surface, oxidizing the aluminum nitride ceramic substrate for 4 hours at 1050 ℃ in the atmosphere, wherein the surface oxidized state is shown in figure 3a, and then fixing the aluminum nitride ceramic substrate on a workbench;

(3) setting spraying process parameters, wherein the spraying starting coordinate (X is 25mm, Y is 25mm), the spraying ending coordinate (X is 65mm, Y is 65mm), the spraying current is 150A, the distance from a spray gun opening to a ceramic substrate is 5.5cm, the spraying speed is 200mm/s, the number of sprayed layers is 3 (the thickness is about 20 mu m), the powder feeding rate is set to be 35 percent (4mg/s), and the carrier gas flow rate is 5L/min;

(4) setting the flow rate of plasma at 10 liters/minute in a plasma power box, setting the preheating and purging current value of the plasma at 200A, purging time at 5s and substrate temperature at 250 ℃, then starting spraying operation, and obtaining a copper-coated aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 20 seconds (as shown in figure 7);

(5) the surface SEM image of the copper-clad high thermal conductivity aluminum nitride ceramic substrate manufactured in this example was flat and uniform, and had a room temperature thermal conductivity of 167.12W (K.m) and a resistivity of 3.01X 10^-3Omega. mm, and the bonding strength between copper and the aluminum nitride ceramic substrate was 7.59 MPa.

Example 2:

in this embodiment, the equipment used in the atmospheric plasma spraying technology is CMD-PA60 type atmospheric plasma spraying equipment.

In this embodiment, the aluminum nitride ceramic circuit board with high thermal conductivity is prepared by applying copper on the surface of aluminum nitride ceramic according to the following steps.

(1) Copper metal powder as shown in b in fig. 1 was added to the atmospheric plasma spray feed system and the argon switch (carrier gas, cooling gas) and plasma gas switch (hydrogen-argon mixture with 5 vol.% hydrogen) were turned on. And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. The designated tungsten electrode and custom powder plasma torch (as shown in fig. 2) were mounted such that a plasma beam was generated between the anode and cathode, part of the plasma beam was outside the torch nozzle, and the formed plasma beam was compressed into a cone shape with a cross section of 1 mm.

(2) The aluminum nitride ceramic substrate with a surface roughness of about 0.3 μm was cleaned in alcohol and acetone to remove organic substances and impurities on the surface, oxidized at 1100 deg.C for 4h in the atmosphere, and the surface oxidized state is shown in FIG. 3b, and then fixed on a stage.

(3) The spraying process parameters were set with a spraying start coordinate (X ═ 15mm, Y ═ 15mm), a spraying current of 150A with an end coordinate (X ═ 55mm, Y ═ 55mm), a distance from the plasma spray gun orifice to the ceramic substrate of 5.5cm, a spraying rate of 200mm/s, 3 layers of sprayed layers (thickness about 20 μm), a powder feed rate of 40% (5mg/s), and a carrier gas flow rate of 5L/min.

(4) Setting the plasma flow rate at 10L/min, the plasma preheating purging current value at 200A, the purging time at 5s and the substrate temperature at 250 ℃ in a plasma power supply box, and then starting the spraying operation to obtain the copper-coated aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 25 seconds (as shown in figure 7).

(5) The surface SEM image of the copper-clad high thermal conductivity aluminum nitride ceramic substrate manufactured in this example was flat and uniform, and had a room temperature thermal conductivity of 164.65W (K · m) and a resistivity of 2.66X 10^-3Omega. mm, and the bonding strength between copper and the aluminum nitride ceramic substrate is 12.57 MPa.

Example 3

In this embodiment, the atmospheric plasma spraying technique uses a Multicoat plasma spraying apparatus.

In this embodiment, the aluminum nitride ceramic circuit board with high thermal conductivity is prepared by applying copper on the surface of aluminum nitride ceramic according to the following steps.

(1) Copper metal powder as shown in b in fig. 1 was added to the atmospheric plasma spray feed system and switched on and off with argon (carrier gas, cooling gas) and plasma gas (argon-hydrogen mixture, with hydrogen content of 5 vol.%). And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. The designated tungsten electrode and custom powder plasma torch (as shown in fig. 2) were installed such that a plasma beam was generated between the positive and negative electrodes, a portion of the plasma beam was outside the torch nozzle, and the formed plasma beam was compressed into a conical shape with a cross section of 1 mm.

(2) Cleaning the aluminum nitride ceramic substrate with the surface roughness of about 0.3 μm in alcohol and acetone to remove organic matters and impurities on the surface, oxidizing at 1150 ℃ for 4h in the atmosphere, wherein the surface is oxidized as shown in fig. 3c, and then fixing on a workbench.

(3) The spraying process parameters were set with a spraying start coordinate (X: 25mm, Y: 25mm), a spraying current of 150A with an end coordinate (X: 65mm, Y: 65mm), a distance from the plasma spray gun nozzle to the ceramic substrate of 5.0cm, a spraying rate of 100mm/s, 3 layers of sprayed layers (thickness about 20 μm), a powder feeding rate of 40% (5mg/s), and a carrier gas flow rate of 5L/min.

(4) Setting the flow rate of plasma at 10L/min, the preheating and purging current value of plasma at 200A, the purging time at 5s and the substrate temperature at 250 ℃ in a plasma power supply box, and then starting the spraying operation to obtain the copper-coated aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 15 seconds (as shown in figure 7).

(5) The surface SEM image of the copper-clad aluminum nitride ceramic substrate prepared in this example was flat and uniform, and had a thermal conductivity of 129.60W (K.m) at room temperature and a resistivity of 3.08X 10^-3Omega mm, the bonding strength of copper and the aluminum nitride ceramic substrate is 17.65 MPa.

Example 4

In this embodiment, the equipment used in the atmospheric plasma spraying technology is GTS plasma spraying equipment.

In this embodiment, the aluminum nitride ceramic circuit board with high thermal conductivity is prepared by applying copper on the surface of aluminum nitride ceramic according to the following steps.

(1) The copper metal powder as shown in b of fig. 1 was added to the atmospheric plasma spray feed system and the argon switch (plasma gas), nitrogen switch (cooling gas and carrier gas) was turned on. And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. The designated tungsten electrode and custom powder plasma torch (as shown in fig. 2) were installed such that a plasma beam was generated between the positive and negative electrodes, a portion of the plasma beam was outside the torch nozzle, and the formed plasma beam was compressed into a conical shape with a cross section of 1 mm.

(2) The aluminum nitride ceramic substrate having a surface roughness of about 0.3 μm was cleaned in alcohol and acetone to remove organic substances and impurities on the surface, oxidized for 4 hours at 1200 □ in the atmosphere, and the surface was oxidized as shown in fig. 3d and then fixed on a stage.

(3) The spraying process parameters were set with a spraying start coordinate (X ═ 15mm, Y ═ 15mm), a spraying current of 150A with an end coordinate (X ═ 55mm, Y ═ 55mm), a distance from the plasma spray gun orifice to the ceramic substrate of 5.5cm, a spraying rate of 50mm/s, 3 layers of sprayed layers (thickness about 20 μm), a powder feed rate of 45% (5mg/s), and a carrier gas flow rate of 5L/min.

(4) Setting the flow rate of plasma at 10L/min, the preheating and purging current value of plasma at 200A, the purging time at 5s and the substrate temperature at 250 ℃ in a plasma power supply box, starting the spraying operation, and obtaining the copper-coated aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 30 days (as shown in figure 7).

(5) The surface SEM image of the copper-clad aluminum nitride ceramic substrate prepared in this example was flat and uniform, and had a thermal conductivity of 126.27W (K · m) at room temperature and a resistivity of 3.15 × 10^-3Omega. mm, and the bonding strength between copper and the aluminum nitride ceramic substrate was 13.79 MPa.

Example 5

In this embodiment, the equipment used in the atmospheric plasma spraying technique is AT-300 plasma spraying equipment. In this embodiment, the aluminum nitride ceramic circuit board with high thermal conductivity is prepared by applying copper on the surface of aluminum nitride ceramic according to the following steps.

(1) The copper metal powder as shown in b in fig. 1 was added to the atmospheric plasma spray feed system and the argon switch (carrier gas, cooling gas and plasma gas) was turned on. And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. The designated tungsten electrode and custom powder plasma torch (see fig. 2) were mounted according to the characteristics of the copper metal powder so that a plasma beam was generated between the positive and negative electrodes, part of the plasma beam was outside the torch nozzle, and the formed plasma beam was compressed into a conical shape with a cross section of 1 mm.

(2) Cleaning the aluminum nitride ceramic substrate with surface roughness of about 0.3 μm in alcohol and acetone to remove organic substances and impurities on the surface, oxidizing at 1250 deg.C in the atmosphere for 4h, and fixing on a workbench in the state after surface oxidation as shown in FIG. 3 e.

(3) The spraying process parameters were set, the spraying start coordinate (X is 25mm, Y is 25mm), the spraying end coordinate (X is 65mm, Y is 65mm), the spraying current was 150A, the distance from the plasma spray gun nozzle to the ceramic substrate was 5.5cm, the spraying rate was 200mm/s, the number of sprayed layers was 3 (thickness about 20 μm), the powder feeding rate was set to 50% (5mg/s), and the carrier gas flow rate was 5L/min.

(4) Setting the flow rate of plasma at 10L/min, the preheating purging current value at 200A and the purging time at 5s in a plasma power supply box, starting the spraying operation, and obtaining the copper-coated aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 25 seconds (as shown in figure 7).

(5) The surface SEM image of the copper-clad aluminum nitride ceramic substrate prepared in this example was flat and uniform, and had a room temperature thermal conductivity of 99.39W (K.m) and a resistivity of 5.2X 10^-3Omega. mm, and the bonding strength between copper and the aluminum nitride ceramic substrate is 3.58 MPa.

Example 6

In this example, the apparatus used in the atmospheric plasma spraying technique was Micro-Nanoparticle Coater-1700013.

In this example, the aluminum nitride ceramic circuit board was prepared by coating copper alloy on the surface of aluminum nitride ceramic according to the following procedure.

(1) Adding metal copper alloy powder (65% by mass of copper and the balance of Ni) with the particle size of 1-30 micrometers into an atmospheric plasma spraying feeding system, and starting an argon switch (carrier gas, cooling gas and plasma gas). And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. According to the characteristics of the metallic copper alloy powder, a designated tungsten electrode and a custom-made powder plasma torch (see fig. 2) were installed such that a plasma beam was generated between the positive and negative electrodes, a part of the plasma beam was outside the nozzle of the torch, and the formed plasma beam was compressed into a conical shape with a cross section of 1 mm.

(2) The aluminum nitride ceramic substrate with the surface roughness of about 0.3 mu m is cleaned in alcohol and acetone to remove organic matters and impurities on the surface, oxidized for 4 hours at 1100 ℃ in the atmosphere and then fixed on a workbench.

(3) The spraying process parameters were set with a spraying start coordinate (X15 mm, Y15 mm), an end coordinate (X55 mm, Y55 mm), a spraying current of 150A, a plasma gun nozzle to ceramic substrate distance of 4.5cm, a spraying rate of 180mm/s, 3 layers (thickness about 20 μm) of sprayed layers, a powder feed rate of 60% (7mg/s), and a carrier gas flow rate of 5L/min.

(4) Setting the flow rate of plasma at 10L/min, the preheating purging current value at 200A and the purging time at 5s in a plasma power supply box, starting the spraying operation, and obtaining the copper-clad copper alloy aluminum nitride ceramic substrate with excellent surface appearance and high adhesive force after 25 seconds (as shown in figure 7).

(5) The surface SEM image of the copper-clad copper alloy aluminum nitride ceramic substrate manufactured in this example is flat and uniform, the room temperature thermal conductivity is 140.43W (K.m), and the resistivity is 3.31X 10^-3Omega mm, the bonding strength of the copper-copper alloy layer and the aluminum nitride ceramic substrate is 14.61 MPa.

Comparative example 1

In this comparative example, the apparatus used in the plasma spraying technique was an APS-2000 plasma spraying apparatus.

In this comparative example, an aluminum nitride ceramic circuit board was prepared by applying copper to the surface of aluminum nitride ceramic in the following manner.

(1) A metallic copper alloy powder as shown in b of fig. 1 (copper alloy same as in example 6) was added to the plasma spray feed system. The main switch, the power switch, the air and argon gas switch (argon is only powder feeding and plasma gas, since a common spray gun does not relate to shielding gas), the air compressor and the dust collector switch of the spraying equipment are sequentially turned on, and the running program is set to enable the cooling water to run. A conventional plasma torch is installed such that a plasma beam is generated inside a torch nozzle.

(2) The aluminum nitride ceramic substrate with the surface roughness of about 0.3 mu m is cleaned in alcohol and acetone to remove organic matters and impurities on the surface, oxidized for 4 hours at 1100 ℃ in the atmosphere and then fixed on a workbench.

(3) The spraying process parameters were set, the spraying start coordinate (X is 25mm, Y is 25mm), the spraying end coordinate (X is 65mm, Y is 65mm), the spraying current was 150A, the distance from the plasma spray gun nozzle to the ceramic substrate was 5.5cm, the spraying rate was 200mm/s, the number of sprayed layers was 3 (thickness was about 20 μm), the powder feeding rate was set to 50% (5mg/s), the carrier gas flow rate was 5L/min, and the coating width was 5 mm.

(4) Setting the plasma flow rate at 10L/min, setting the plasma preheating and purging current value at 200A and the purging time at 5s in a plasma power supply box, starting the spraying operation, and obtaining the copper-clad aluminum nitride ceramic substrate after 25 seconds.

(5) The copper-clad aluminum nitride ceramic substrate manufactured by the comparative example has serious delaminating between copper and an aluminum nitride substrate, and the oxidation content of copper reaches more than 90 percent. The bonding strength was 0.02MPa, the thermal conductivity at room temperature was 25.24W (K · m), and the resistivity was 6.1X 10⁵Ω·mm。

Comparative example 2

In this comparative example, the apparatus used in the plasma spraying technique was a GTS plasma spraying apparatus.

In this comparative example, an aluminum nitride ceramic circuit board was prepared by applying copper to the surface of aluminum nitride ceramic in the following manner.

(1) The copper metal powder as shown in b of fig. 1 was added to the plasma spray feed system and the argon switch was turned on (argon was the shielding gas, plasma gas and carrier gas). And sequentially turning on a main switch, a power switch, each gas switch, an air compressor and a dust collector switch of the spraying equipment, and setting an operation program to enable the cooling water to operate. According to the characteristics of the metal copper powder, a designated tungsten electrode and a customized powder plasma spray gun (as shown in figure 2) are installed, and a plasma beam is generated outside a spray gun nozzle.

(2) Cleaning the aluminum nitride ceramic substrate with surface roughness of about 0.3 μm in alcohol and acetone to remove organic substances and impurities on the surface, oxidizing at 1000 deg.C for 4h in the atmosphere, and fixing on a worktable after the surface is oxidized as shown in FIG. 3 f.

(3) The spraying process parameters were set, the spraying start coordinate (X ═ 20mm, Y ═ 20mm), the spraying end coordinate (X ═ 60mm, Y ═ 60mm), the spraying current was 150A, the distance from the plasma spray gun orifice to the ceramic substrate was 5.5cm, the spraying rate was 200mm/s, the number of sprayed layers was 3 (thickness about 20 μm), the powder feed rate was set at 50% (5mg/s), and the carrier gas flow rate was 5L/min.

(4) Setting the plasma flow rate at 10L/min, setting the plasma preheating and purging current value at 200A and the purging time at 5s in a plasma power supply box, starting the spraying operation, and obtaining the copper-coated aluminum nitride ceramic substrate after 25 seconds.

(5) In this comparative example, the aluminum nitride surface oxidized at 1000 ℃ for 4 hours did not form an aluminum oxide film (as shown in FIG. 4), and the metal layer of the copper-clad aluminum nitride ceramic substrate was separated from the ceramic substrate, and the substrate had a thermal conductivity of 40.21W (K.m) at room temperature and a resistivity of 4.5X 10⁵Omega. mm, and the bonding strength between copper and the aluminum nitride ceramic substrate is 0.001 MPa.

Comparative example 3

The production method of the aluminum nitride ceramic copper-clad plate comprises the traditional Mo-Mn method, high temperature sintering (HTCC), low temperature sintering (LTCC), thin film method (DPC), direct bonding copper method (DBC) and the like.

Prior art 1: jiangx, preparation and performance research of aluminum nitride ceramic direct copper-clad substrate [ D ], Master thesis of Hunan university, 2015, reported that oxidized aluminum nitride ceramic is bonded with a copper sheet at high temperature, and the bonding strength is more than 7MPa.

Prior art 2: zibo Yinhe high technology development Co., Ltd preoxidizes aluminum nitride ceramics in the air, and then copper is coated by a DBC method, and the bonding strength is more than 4 MPa.

Prior art 3: the effect of heat treatment on the chemical copper plating structure performance of aluminum nitride in Helianthus arborescens is 1001 and 3660(2020)02-0288-07, and the combination strength of the Cu-AlN substrate with excellent comprehensive performance is 32.6N.

Compared with the prior art, the aluminum nitride ceramic plate is directly coated with copper by adopting an atmospheric plasma spraying method, and a specific copper electrode circuit can be formed by one step, the heat conductivity coefficient at room temperature can reach 167.12W (K.m), and the bonding strength can reach 17.65 MPa.

Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.