Method and system for preparing metal circuit on aluminum nitride ceramic substrate

Abstract

The invention provides a method and a system for preparing a metal circuit on an aluminum nitride ceramic substrate. Nickel metal powder is sprayed on the aluminum nitride ceramic substrate covered with a circuit mask through atmospheric plasma to obtain a high-thermal-conductivity ceramic circuit substrate coated with the nickel metal circuit. The method comprises the following steps: selecting nickel and other metal or nickel alloy powder with a proper particle size, melting the nickel metal or nickel alloy powder by using atmospheric plasma spraying, and spraying the molten nickel metal or nickel alloy powder on the surface of an aluminum nitride ceramic substrate covered with a specifically designed circuit pattern mask; and a plurality of process parameters and a plasma torch structure are adjusted to prepare the aluminum nitride ceramic circuit substrate with high interface bonding strength and high conductivity. According to the method, the mask plates with different circuit patterns are designed, and the aluminum nitride ceramic circuit substrate with different circuit patterns and controllable line width precision can be directly obtained after the nickel metal or alloy powder is directly melted and sprayed through the plasma spray gun.

Description

Technical Field

[0001] The present invention relates to the technical field of metal circuit preparation, and in particular to a method and system for preparing a metal circuit on an aluminum nitride ceramic substrate. Background Art

[0002] With the advent of the information age, electronic components are increasingly moving towards miniaturization, high speed, and high integration. Heat dissipation, driven by high power and lightweight design, has become a bottleneck in the development of power-based electronic products. The increasing integration of electronic systems inevitably leads to higher power density in electronic devices, which in turn increases the heat generated by electronic components and systems. The continuous accumulation of heat within power-based electronic components increases chip junction temperatures, generating thermal stress and leading to a series of reliability issues such as reduced lifespan. Over 80% of this heat is dissipated through conduction through the substrate, while only 20% is dissipated through radiation and convection. Furthermore, heat dissipation substrates also serve as electrical connections and mechanical support. For power-based electronic devices, their packaging substrates must possess high thermal conductivity, insulation, and heat resistance, as well as high strength and a thermal expansion coefficient that matches the chip.

[0003] Currently, commonly used electronic packaging substrate materials mainly include three categories: organic polymers, metals and metal-based composites, and ceramics. Among them, organic polymer packaging substrates have poor thermal conductivity and electrical properties, low reliability, and are not suitable for use in high-power electronic systems. Metal packaging substrate materials have high thermal conductivity, but the linear expansion coefficient does not match and they are expensive, so they are not suitable for widespread use. Aluminum nitride ceramic substrate materials have broad application prospects in the packaging field of high-power optoelectronic devices due to their high insulation, high chemical stability, excellent mechanical properties, high thermal conductivity, and thermal expansion coefficients that match a variety of semiconductor device materials. However, in actual production, the molding process of aluminum nitride ceramic substrate materials is an important factor restricting its application prospects.

[0004] Among ceramic substrates, aluminum nitride is the most widely used due to its good comprehensive mechanical properties, high thermal conductivity, low thermal expansion coefficient, low price, and ease of large-scale molding and production. At present, the mainstream methods for preparing metal circuits on aluminum nitride ceramic substrates are mainly the Mo-Mn method, direct nickel coating method, and thin film method. The Mo-Mn method is based on heat-resistant metal Mo powder, with Mn powder added, and printed on the surface of the aluminum nitride ceramic substrate. It is then sintered at high temperature in a humidified hydrogen atmosphere to form a metallized layer. The coating metal sintered by this method has a strong bond with the ceramic, but direct welding is difficult and the conductivity is not ideal. Generally, Ni, Au, Ag, etc. must be electroplated on its surface. In addition, the temperature required for sintering is relatively high, and the interface layer is prone to generate large internal stress. The thin film method uses coating technologies such as vacuum evaporation and sputtering. Considering the need to improve the bonding strength between the metal film layer and the substrate and the reactivity between the ceramic and metal film layers, the Ti slurry system is currently the most studied. The Ti layer is generally tens of nanometers in thickness, and a metal layer with high conductivity and low oxidation resistance, such as Ag, Pt, Ni, and Cu, is deposited on the surface of the Ti layer to alleviate the thermal stress caused by the mismatch in thermal expansion coefficients. The main advantages of the thin film method are uniform metal layers and high bonding strength, but the disadvantages are large equipment investment, difficulty in production, and difficulty in achieving industrial scale. The direct nickel coating method introduces an appropriate amount of active metal elements between nickel and the ceramic substrate, sintering at a high temperature of 1065°C-1083°C, and using the metal's nitrogen-containing eutectic liquid to apply the metal layer to the surface of the ceramic substrate. However, this method requires extremely strict temperature control, and the nickel-coated metal layer also needs to be processed later.

[0005] Patent application document CN113149715A discloses a multi-layer metal-coated, high-thermal-conductivity aluminum nitride ceramic substrate and its preparation method. The preparation method uses metal nickel or nickel alloy powder and metal copper or copper alloy powder, respectively, and sprays the metal or metal alloy powder in a molten state onto the surface of an aluminum nitride ceramic substrate covered with a specific pattern mask using atmospheric plasma spraying technology. By adjusting various process parameters and the plasma spray gun structure, a multi-layer metal-coated aluminum nitride ceramic substrate with high interface bonding strength between the metal layer and the aluminum nitride ceramic, high thermal conductivity, and high electrical conductivity is prepared. However, this patent cannot completely solve the existing technical problems, nor can it meet the requirements of the present invention. Summary of the Invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a method and system for preparing metal circuits on an aluminum nitride ceramic substrate.

[0007] The method for preparing a metal circuit on an aluminum nitride ceramic substrate provided by the present invention comprises:

[0008] Step 1: Add nickel metal or nickel alloy powder of a preset particle size into an atmospheric plasma spraying device under inert gas protection;

[0009] Step 2: Install a custom plasma spray gun with an anti-oxidation design, where the nozzle is enveloped in an inert gas as it sprays the molten metal.

[0010] Step 3: sandblast the aluminum nitride ceramic substrate to ensure that its surface roughness meets the preset requirements, then clean it and fix it on the spraying platform;

[0011] Step 4: Covering the substrate surface with a mask etched with a circuit pattern;

[0012] Step 5: Set the spraying parameters, including spraying current, spray gun distance, spray gun movement rate, powder feeding rate, carrier gas flow rate and plasma flow rate;

[0013] Step 6: Blow the substrate with a plasma flame beam before spraying;

[0014] Step 7: Form a nickel metal or nickel alloy circuit layer of a preset thickness on the substrate by spraying.

[0015] Preferably, the mask is made of stainless steel, aluminum alloy, copper or copper alloy, has a thickness of 0.2 μm to 1 mm, a minimum line width of 15 μm, and a line width accuracy of ±2 μm.

[0016] Preferably, the spraying parameters include: spraying current of 100A to 250A, spray gun distance of 4cm to 10cm, spray gun movement rate of 50mm / s to 200mm / s, powder feeding rate of 3mg / s to 10mg / s, carrier gas flow rate of 3L / min to 7L / min, and plasma flow rate of 8L / min to 12L / min.

[0017] Preferably, the surface roughness of the substrate after sandblasting is 3 μm to 5 μm;

[0018] Before spraying, the substrate is purged with a plasma flame beam for 5s to 10s with a purging current of 100A to 200A.

[0019] Preferably, the particles of the nickel metal or nickel alloy powder are spherical.

[0020] The system for preparing a metal circuit on an aluminum nitride ceramic substrate provided by the present invention comprises:

[0021] Module M1: Add nickel metal or nickel alloy powder of preset particle size into atmospheric plasma spraying equipment, using inert gas protection;

[0022] Module M2: sandblasting the aluminum nitride ceramic substrate to ensure that its surface roughness meets the preset requirements, then cleaning it and fixing it on the spraying platform;

[0023] Module M3: Covering the substrate surface with a mask etched with a circuit pattern;

[0024] Module M4: Setting spraying parameters, including spraying current, spray gun distance, spray gun movement rate, powder feeding rate, carrier gas flow rate and plasma flow rate;

[0025] Module M5: Plasma flame beam purging of the substrate before spraying;

[0026] Module M6: Forming a nickel metal or nickel alloy circuit layer of a preset thickness on the substrate by spraying.

[0027] Preferably, the mask is made of stainless steel, aluminum alloy, copper or copper alloy, has a thickness of 0.2 μm to 1 mm, a minimum line width of 15 μm, and a line width accuracy of ±2 μm.

[0028] Preferably, the spraying parameters include: spraying current of 100A to 250A, spray gun distance of 4cm to 10cm, spray gun movement rate of 50mm / s to 200mm / s, powder feeding rate of 3mg / s to 10mg / s, carrier gas flow rate of 3L / min to 7L / min, and plasma flow rate of 8L / min to 12L / min.

[0029] Preferably, the surface roughness of the substrate after sandblasting is 3 μm to 5 μm;

[0030] Before spraying, the substrate is purged with a plasma flame beam for 5s to 10s with a purging current of 100A to 200A.

[0031] Preferably, the particles of the nickel metal or nickel alloy powder are spherical.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention can prepare nickel metal or nickel alloy coatings with high bonding strength, excellent electrical properties, and controllable patterns through controllable process parameters and spray gun structure design;

[0034] (2) The present invention adopts atmospheric plasma spraying technology to achieve rapid and large-area preparation, with simple preparation steps, low cost and high raw material utilization rate;

[0035] (3) The present invention is suitable for spraying with a variety of metal powders and alloy powders, and the coating performance is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0037] Figure 1This is a flow chart of the method for preparing a metal circuit on an aluminum nitride ceramic substrate according to the present invention;

[0038] Figure 2 The morphology and size distribution of the raw nickel powder used in various embodiments of the present invention;

[0039] Figure 3 This is a structural diagram of the plasma spray gun used in the present invention;

[0040] Figure 4 Surface electron microscopy (SEM) photos of aluminum nitride-coated nickel metal circuits prepared in various embodiments of the present invention;

[0041] Figure 5 This is the XRD pattern of the aluminum nitride nickel-coated metal circuit obtained in Example 3 of the present invention;

[0042] Figure 6 This is a scanning electron micrograph (SEM) of a cross-section of an aluminum nitride-coated nickel metal circuit prepared in Example 3 of the present invention;

[0043] Figure 7 The invention provides an aluminum nitride nickel-clad metal circuit with a specific electrode pattern. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0045] Example 1

[0046] like Figure 1 The present invention provides a method for preparing a metal circuit on an aluminum nitride ceramic substrate, comprising:

[0047] Step 1: Add nickel metal or nickel alloy powder of a preset particle size into an atmospheric plasma spraying device under inert gas protection;

[0048] Step 2: Install a custom plasma spray gun with an anti-oxidation design, where the nozzle is enveloped in an inert gas as it sprays the molten metal.

[0049] Step 3: sandblast the aluminum nitride ceramic substrate to ensure that its surface roughness meets the preset requirements, then clean it and fix it on the spraying platform;

[0050] Step 4: Cover the substrate surface with the mask etched with the circuit pattern; Figure 7 , which is an aluminum nitride nickel-clad plate with a specific electrode pattern;

[0051] Step 5: Set the spraying parameters, including spraying current, spray gun distance, spray gun movement rate, powder feeding rate, carrier gas flow rate and plasma flow rate;

[0052] Step 6: Blow the substrate with a plasma flame beam before spraying;

[0053] Step 7: Form a nickel metal or nickel alloy circuit layer of a preset thickness on the substrate by spraying.

[0054] The mask is made of stainless steel, aluminum alloy, copper or copper alloy, has a thickness of 0.2 μm to 1 mm, a minimum line width of 15 μm, and a line width accuracy of ±2 μm.

[0055] The spraying parameters include: spraying current of 100A to 250A, spray gun distance of 4cm to 10cm, spray gun movement rate of 50mm / s to 200mm / s, powder feeding rate of 3mg / s to 10mg / s, carrier gas flow rate of 3L / min to 7L / min, and plasma flow rate of 8L / min to 12L / min.

[0056] The surface roughness of the substrate after sandblasting is 3 μm to 5 μm;

[0057] Before spraying, the substrate is purged with a plasma flame beam for 5s to 10s with a purging current of 100A to 200A.

[0058] The selected nickel metal and its alloy powder has a particle size distribution between 10 and 60 μm and a spherical shape. Figure 2 As shown, the raw metal powder has high sphericity and narrow particle size distribution, which can improve the efficiency of spraying in various links such as feeding, heating and deposition, and help to obtain high-quality and high-density surface metal coatings.

[0059] Figure 4 、 Figure 5 and Figure 6 It can be proved that the method provided by the present invention successfully prepared a high-quality metal layer on an aluminum nitride ceramic substrate. The metal layer is uniform, continuous, dense, damage-free, free of impurity phases, and has not been oxidized. At the same time, the metal film / circuit forms good contact with the substrate, which improves the bonding strength of the metal film. Figure 7 It can be seen that the method proposed in the present invention can be used to prepare high-precision circuits on the surface of an aluminum nitride substrate. An aluminum nitride substrate is used, and the circuits thereon are metal circuits manufactured by the method of the present invention.

[0060] Example 2

[0061] The present invention provides a method for rapidly preparing an aluminum nitride ceramic circuit board, comprising the following steps:

[0062] (1) Add metal nickel powder with an average particle size of 30 microns into the atmospheric plasma spraying feeding system and turn on the argon switch. Turn on the main switch, power switch, various gas switches, air compressor and vacuum cleaner switches of the spraying equipment in sequence, set the operating program to run the cooling water. According to the characteristics of the metal nickel powder, install the specified tungsten electrode head and customized powder plasma spray gun head, such as Figure 3 The spray gun head includes a plasma ionization chamber, an electrode, a cooling gas device and a cooling liquid device, wherein the plasma ionization chamber includes a plasma nozzle, a powder feeding channel and a plasma gas channel; when working, the nozzle and the electrode serve as the positive and negative poles of the electrode respectively, and ignite the arc through high-frequency or DC sparks to ionize the gas. The ionized gas has a very high pressure after three compression effects of mechanical, self-magnetic and thermal compression and is ejected from the nozzle.

[0063] (2) The aluminum nitride substrate with a surface roughness of about 3 μm after sandblasting was cleaned in alcohol and acetone to remove organic matter and impurities on the surface, and then fixed on a plasma spraying workbench.

[0064] (3) Set the spraying process parameters: the spraying current is 130A, the distance from the spray gun nozzle to the ceramic substrate is 5.5cm, the spraying rate is 200mm / s, the number of spray layers is 5 layers (thickness is about 50μm), the powder feeding rate is set to 45% (5mg / s), the carrier gas flow rate is 5L / min, and the coating width is 5mm.

[0065] (4) The plasma flow rate in the plasma power box is set to 12 liters / minute, the plasma preheating purge current value is set to 200A, and the purge time is set to 5 seconds. Then the spraying operation begins. After a period of time, a nickel electrode with excellent surface morphology and high adhesion is obtained.

[0066] Example 3

[0067] The present invention provides a method for rapidly preparing an aluminum nitride ceramic circuit board, comprising the following steps:

[0068] (1) Add nickel powder with an average particle size of 40 microns into the atmospheric plasma spraying feed system and turn on the argon switch. Turn on the main switch, power switch, various gas switches, air compressor and vacuum cleaner switches of the spraying equipment in sequence, set the operating program to run the cooling water. According to the characteristics of the nickel powder, install the specified tungsten electrode head and customized powder plasma spray gun head.

[0069] (2) The aluminum nitride substrate with a surface roughness of about 3 μm after sandblasting is cleaned in alcohol and acetone to remove organic matter and impurities on the surface, and then fixed on a workbench.

[0070] (3) Set the spraying process parameters: the spraying current is 150A, the distance from the plasma spray gun nozzle to the ceramic substrate is 5.5cm, the spraying rate is 200mm / s, the number of spray layers is 5 layers (thickness is about 50μm), the powder feeding rate is set to 45% (5mg / s), the carrier gas flow rate is 5L / min, and the coating width is 5mm.

[0071] (4) The plasma flow rate in the plasma power box is set to 12 L / min, the plasma preheating purge current value is set to 200 A, and the purge time is set to 5 s. Then the spraying operation begins. After a period of time, a nickel electrode with excellent surface morphology and high adhesion is obtained.

[0072] Example 4

[0073] The present invention provides a method for rapidly preparing an aluminum nitride ceramic circuit board, comprising the following steps:

[0074] (1) Add nickel powder with an average particle size of 50 microns into the atmospheric plasma spray feeding system and turn on the argon switch. Turn on the main switch, power switch, various gas switches, air compressor and vacuum cleaner switches of the spray equipment in sequence, set the operating program to run the cooling water. According to the characteristics of the metallic nickel powder, install the specified tungsten electrode head and customized powder plasma spray gun head.

[0075] (2) The aluminum nitride substrate with a surface roughness of about 3 μm after sandblasting is cleaned in alcohol and acetone to remove organic matter and impurities on the surface, and then fixed on a workbench.

[0076] (3) Set the spraying process parameters: the spraying current is 150A, the distance from the plasma spray gun nozzle to the ceramic substrate is 5.0cm, the spraying rate is 200mm / s, the number of spray layers is 5 layers (thickness is about 50μm), the powder feeding rate is set to 45% (5mg / s), the carrier gas flow rate is 5L / min, and the coating width is 5mm.

[0077] (4) The plasma flow rate in the plasma power box is set to 12 L / min, the plasma preheating purge current value is set to 200 A, and the purge time is set to 5 s. Then the spraying operation begins. After a period of time, a nickel electrode with excellent surface morphology and high adhesion is obtained.

[0078] Example 5

[0079] The present invention provides a method for rapidly preparing an aluminum nitride ceramic circuit board, comprising the following steps:

[0080] (1) Add nickel powder with an average particle size of 60 microns into the atmospheric plasma spraying feed system and turn on the argon switch. Turn on the main switch, power switch, various gas switches, air compressor and vacuum cleaner switches of the spraying equipment in sequence, set the operating program to run the cooling water. According to the characteristics of the nickel powder, install the specified tungsten electrode head and customized powder plasma spray gun head.

[0081] (2) The aluminum nitride substrate with a surface roughness of about 3 μm after sandblasting is cleaned in alcohol and acetone to remove organic matter and impurities on the surface, and then fixed on a workbench.

[0082] (3) Set the spraying process parameters: the spraying current is 150A, the distance from the plasma spray gun nozzle to the ceramic substrate is 5.5cm, the spraying rate is 50mm / s, the number of spray layers is 5 layers (thickness is about 50μm), the powder feeding rate is set to 45% (5mg / s), the carrier gas flow rate is 5L / min, and the coating width is 5mm.

[0083] (4) The plasma flow rate in the plasma power box is set to 12 L / min, the plasma preheating purge current value is set to 200 A, and the purge time is set to 5 s. Then the spraying operation begins. After a period of time, a nickel electrode with excellent surface morphology and high adhesion is obtained.

[0084] Example 6

[0085] The present invention provides a method for rapidly preparing an aluminum nitride ceramic circuit board, comprising the following steps:

[0086] (1) Add metallic nickel powder with an average particle size of 70 microns into the atmospheric plasma spray feeding system and turn on the argon switch. Turn on the main switch, power switch, various gas switches, air compressor and vacuum cleaner switches of the spray equipment in sequence, set the operating program to run the cooling water. According to the characteristics of the metallic nickel powder, install the specified tungsten electrode head and customized powder plasma spray gun head.

[0087] (2) The aluminum nitride substrate with a surface roughness of about 3 μm after sandblasting is cleaned in alcohol and acetone to remove organic matter and impurities on the surface, and then fixed on a workbench.

[0088] (3) Set the spraying process parameters: the spraying current is 150A, the distance from the plasma spray gun nozzle to the ceramic substrate is 5.5cm, the spraying rate is 200mm / s, the number of spray layers is 5 layers (thickness is about 50μm), the powder feeding rate is set to 50% (5mg / s), the carrier gas flow rate is 5L / min, and the coating width is 5mm.

[0089] (4) The plasma flow rate in the plasma power box is set to 12 L / min, the plasma preheating purge current value is set to 200 A, and the purge time is set to 5 s. Then the spraying operation begins. After a period of time, a nickel electrode with excellent surface morphology and high adhesion is obtained.

[0090] Those skilled in the art will appreciate that, in addition to implementing the system, device, and various modules provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like by logically programming the method steps. Therefore, the system, device, and various modules provided by the present invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; the modules for implementing various functions can also be considered both software programs for implementing the method and structures within the hardware component.

[0091] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for preparing a metal circuit on an aluminum nitride ceramic substrate, characterized in that: include: Step 1: Add nickel metal or nickel alloy powder of a preset particle size into an atmospheric plasma spraying device under inert gas protection; Step 2: Install a custom plasma spray gun with an anti-oxidation design, where the nozzle is enveloped in an inert gas as it sprays the molten metal. Step 3: sandblast the aluminum nitride ceramic substrate to ensure that its surface roughness meets the preset requirements, then clean it and fix it on the spraying platform; Step 4: Covering the substrate surface with a mask etched with a circuit pattern; Step 5: Set the spraying parameters, including spraying current, spray gun distance, spray gun movement rate, powder feeding rate, carrier gas flow rate and plasma flow rate; Step 6: Blow the substrate with a plasma flame beam before spraying; Step 7: Form a nickel metal or nickel alloy circuit layer of a preset thickness on the substrate by spraying.

2. The method for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 1, wherein: The mask is made of stainless steel, aluminum alloy, copper or copper alloy, has a thickness of 0.2 μm to 1 mm, a minimum line width of 15 μm, and a line width accuracy of ±2 μm.

3. The method for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 1, wherein: The spraying parameters include: spraying current of 100A to 250A, spray gun distance of 4cm to 10cm, spray gun movement rate of 50mm / s to 200mm / s, powder feeding rate of 3mg / s to 10mg / s, carrier gas flow rate of 3L / min to 7L / min, and plasma flow rate of 8L / min to 12L / min.

4. The method for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 1, wherein: The surface roughness of the substrate after sandblasting is 3 μm to 5 μm; Before spraying, the substrate is purged with a plasma flame beam for 5s to 10s with a purging current of 100A to 200A.

5. The method for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 1, wherein: The particles of the nickel metal or nickel alloy powder are spherical.

6. A system for preparing metal circuits on an aluminum nitride ceramic substrate, characterized in that: include: Module M1: Add nickel metal or nickel alloy powder of preset particle size into atmospheric plasma spraying equipment, using inert gas protection; Module M2: sandblasting the aluminum nitride ceramic substrate to ensure that its surface roughness meets the preset requirements, then cleaning it and fixing it on the spraying platform; Module M3: Covering the substrate surface with a mask etched with a circuit pattern; Module M4: Setting spraying parameters, including spraying current, spray gun distance, spray gun movement rate, powder feeding rate, carrier gas flow rate and plasma flow rate; Module M5: Plasma flame beam purging of the substrate before spraying; Module M6: Forming a nickel metal or nickel alloy circuit layer of a preset thickness on the substrate by spraying.

7. The system for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 6, wherein: The mask is made of stainless steel, aluminum alloy, copper or copper alloy, has a thickness of 0.2 μm to 1 mm, a minimum line width of 15 μm, and a line width accuracy of ±2 μm.

8. The system for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 6, wherein: The spraying parameters include: spraying current of 100A to 250A, spray gun distance of 4cm to 10cm, spray gun movement rate of 50mm / s to 200mm / s, powder feeding rate of 3mg / s to 10mg / s, carrier gas flow rate of 3L / min to 7L / min, and plasma flow rate of 8L / min to 12L / min.

9. The system for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 6, wherein: The surface roughness of the substrate after sandblasting is 3 μm to 5 μm; Before spraying, the substrate is purged with a plasma flame beam for 5s to 10s with a purging current of 100A to 200A.

10. The system for preparing a metal circuit on an aluminum nitride ceramic substrate according to claim 6, wherein: The particles of the nickel metal or nickel alloy powder are spherical.

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