Circuit board with embedded copper core aluminum nitride ceramic high-heat-dissipation module and preparation process of circuit board

Abstract

The invention provides a preparation process of a circuit board with an embedded copper core aluminum nitride ceramic high-heat-dissipation module. The preparation process comprises the following steps: carrying out first milling and cutting treatment on a plurality of first core plates; pre-stacking the plurality of first core boards, the plurality of second core boards, the plurality of first PP resin layers, the plurality of second PP resin layers and the third PP resin layers to obtain a multi-layer core board group; after the embedded copper core aluminum nitride ceramic high-heat-dissipation module is embedded into the semi-buried groove, the multi-layer core plate set is subjected to pressing treatment; drilling the laminated multi-layer core board group to form a conductive through hole in the multi-layer core board group; carrying out metallization treatment on the multi-layer core board group after the drilling treatment; and performing line manufacturing processing on the multi-layer core board group after metallization processing to obtain the circuit board embedded with the copper core aluminum nitride ceramic high-heat-dissipation module.

Description

Technical Field

[0001] The present disclosure relates to the field of circuit boards, and in particular to a circuit board with an embedded copper-core aluminum nitride ceramic high heat dissipation module and a preparation process thereof. Background Art

[0002] As the power density of electronic devices continues to increase, heat dissipation has become a key challenge in printed circuit board (PCB) design. In order to cope with this problem, a variety of heat dissipation solutions have appeared on the market, such as copper substrates, aluminum substrates, and copper-buried PCBs for local heat dissipation. However, copper substrates and aluminum substrates are widely used in high-power electronic devices due to their excellent thermal conductivity, but they have large metal consumption, high material costs, and their good electrical conductivity limits the flexibility of circuit board design. In addition, metal substrates are usually thicker and difficult to meet the needs of miniaturized design.

[0003] The buried copper block technology is gradually being applied in multi-layer PCB boards. By directly burying the processed heat dissipation module (copper block) into the board, the high thermal conductivity of the copper block can effectively solve the heat dissipation problem of high-power modules. However, due to the good conductivity of the copper block, the circuit pattern cannot be made on the surface of the copper block. Although the copper block can solve the heat dissipation problem, it also occupies the precious space of the circuit board, resulting in limitations in the circuit design of the circuit board. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a circuit board and its preparation process which can be suitable for high-power compact electronic devices and can reduce the space occupied by copper blocks to improve the flexibility of circuit board circuit design.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A preparation process of a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module comprises the following steps:

[0007] Obtain an embedded copper core aluminum nitride ceramic high heat dissipation module, a plurality of first core boards, a plurality of second core boards, a plurality of first PP resin layers, and a plurality of second PP resin layers;

[0008] Performing a first gong cutting process on the plurality of the first core plates, so that the plurality of the first core plates are all formed with a first through groove;

[0009] Pre-stacking a plurality of the first core plates, a plurality of the second core plates, a plurality of the first PP resin layers, and a plurality of the second PP resin layers to obtain a multi-layer core plate group, and connecting a plurality of the first through grooves in sequence to form a semi-buried groove;

[0010] After the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried slot, the multi-layer core board assembly is pressed together;

[0011] Performing drilling processing on the multi-layer core plate group after the pressing processing, so that the multi-layer core plate group is formed with conductive through holes;

[0012] Performing metallization treatment on the multi-layer core plate group after the drilling treatment;

[0013] The multi-layer core board group after metallization treatment is subjected to circuit manufacturing treatment to obtain a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein.

[0014] In one embodiment, after the step of embedding the embedded copper core aluminum nitride ceramic high heat dissipation module into the semi-buried groove of the multi-layer core board group for pressing, and before drilling the multi-layer core board group after the pressing, the preparation process further includes the following steps:

[0015] A second gong cutting process is performed on the side of the multi-layer core plate group away from the embedded copper core aluminum nitride ceramic high heat dissipation module, so that a functional groove connected to the semi-buried groove is formed on the other side of the multi-layer core plate group.

[0016] In one embodiment, the specific operation steps of obtaining the embedded copper core aluminum nitride ceramic high heat dissipation module and multiple core boards are:

[0017] obtaining a copper core block and an aluminum nitride ceramic block;

[0018] Cutting the central area of ​​the aluminum nitride ceramic block so that an embedded cavity is formed in the central area of ​​the aluminum nitride ceramic block;

[0019] Embedding the copper core block into the embedded cavity until one side of the copper core block is flush with one side of the aluminum nitride ceramic block, so as to obtain the embedded copper core aluminum nitride ceramic high heat dissipation module;

[0020] Obtaining a plurality of substrates, a plurality of copper foil layers, a plurality of the first PP resin layers, a plurality of the second PP resin layers, and the third PP resin layer;

[0021] The copper foil layer, the substrate and the copper foil layer are stacked and pressed in a three-layer combination to obtain a plurality of core boards.

[0022] In one embodiment, the specific operation steps of pre-stacking the plurality of first core plates, the plurality of second core plates, the plurality of first PP resin layers and the plurality of second PP resin layers are:

[0023] stacking a plurality of the first core panels and a plurality of the first PP resin layers in the order of the first core panels, the first PP resin layers, and the first core panels to obtain a first core panel group;

[0024] stacking a plurality of the second core plates and a plurality of the second PP resin layers in the order of the second core plates, the second PP resin layers and the second core plates to obtain a second core plate group;

[0025] The multi-layer core plate group is obtained by stacking the second core plate group on the first core plate group and placing one of the first PP resin layers or one of the second PP resin layers between the first core plate group and the second core plate group.

[0026] In one embodiment, the specific operation steps of performing the first gong cutting process on the plurality of the first core boards are:

[0027] The first cutting process is performed on the plurality of first core plates by using a CNC machine tool.

[0028] In one embodiment, the specific operation steps of performing a second gong cutting process on a side of the multi-layer core board assembly away from the embedded copper core aluminum nitride ceramic high heat dissipation module are:

[0029] The CNC machine tool is used to perform a second cutting process on the plurality of second core plates in the multi-layer core plate group.

[0030] In one embodiment, the rotation speed of the first cutting process and the rotation speed of the second cutting process are both 30Krpm to 35Krpm;

[0031] The tool speed of the first cutting process and the tool speed of the second cutting process are both 0.1 m / min to 0.2 m / min.

[0032] In one embodiment, the specific operation steps of performing circuit manufacturing on the multi-layer core board group after metallization are as follows:

[0033] Affixing the anti-corrosion dry film to the surface of the multi-layer core plate assembly by heat pressing;

[0034] Performing outer layer exposure treatment on the multi-layer core board group;

[0035] Performing outer layer development treatment on the multi-layer core board group after the exposure treatment;

[0036] The multi-layer core board group after the development treatment is subjected to an outer layer etching treatment.

[0037] In one embodiment, after the multi-layer core board assembly after the metallization treatment is subjected to circuit manufacturing, the preparation process further comprises the following steps:

[0038] The outer surface of the multi-layer core board group is treated to obtain the circuit board with the copper core aluminum nitride ceramic high heat dissipation module embedded therein.

[0039] A circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein, prepared by using the preparation process for a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein described in any of the above embodiments;

[0040] The circuit board comprises a multi-layer core board group and an embedded copper core aluminum nitride ceramic high heat dissipation module, wherein the multi-layer core board group is formed with a semi-buried groove and a conductive through hole, and the embedded copper core aluminum nitride ceramic high heat dissipation module is arranged in the semi-buried groove.

[0041] Compared with the prior art, the present invention has at least the following advantages:

[0042] 1. Performing a first gong cutting process on a plurality of first core boards, so that a first through groove is formed on each of the plurality of first core boards, and then performing a pre-stacking process on the plurality of first core boards, the plurality of second core boards, the plurality of first PP resin layers, the plurality of second PP resin layers and the third PP resin layer to obtain a multi-layer core board group, and the plurality of first through grooves are sequentially connected to form a semi-buried groove, and then the multi-layer core board group is pressed after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, so that the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the multi-layer core board group, the copper core itself has high thermal conductivity, and directly contacts with the components for heat dissipation during subsequent circuit board mounting, and the aluminum nitride ceramic not only has high thermal conductivity, but also has electrical insulation performance, and the design of the copper core embedded in the aluminum nitride ceramic improves the heat dissipation performance of the circuit board, and the circuit design can also be performed on the aluminum nitride ceramic, so that the circuit board can have a high heat dissipation performance while reducing the space occupied by the copper core, thereby improving the flexibility of the circuit board circuit design.

[0043] 2. Conductive through holes are formed on the multi-layer core board group by drilling the multi-layer core board group, and then a copper layer is plated on the hole wall of the conductive through hole by metallizing the multi-layer core board group to make the multi-layer core boards electrically conductive. At the same time, the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board assembly can be filled with copper, thereby improving the bonding stability between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, thereby effectively improving the mechanical strength and reliability of the circuit board, and further effectively extending the service life of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 It is a flow chart of a process for preparing a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein in one embodiment;

[0046] Figure 2 A schematic diagram of a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein;

[0047] Figure 3 A schematic diagram of a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to another embodiment;

[0048] Figure 4 This is a physical picture of a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module. DETAILED DESCRIPTION

[0049] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0050] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0052] The present invention provides a preparation process of a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module, comprising the following steps: obtaining an embedded copper core aluminum nitride ceramic high heat dissipation module, a plurality of first core boards, a plurality of second core boards, a plurality of first PP resin layers, a plurality of second PP resin layers and a third PP resin layer; performing a first gong cutting process on the plurality of first core boards so that the plurality of first core boards are all formed with a first through groove; performing a pre-stacking process on the plurality of first core boards, the plurality of second core boards, the plurality of first PP resin layers, the plurality of second PP resin layers and the third PP resin layer so as to obtain a multi-layer core board group, and making the plurality of first through grooves sequentially connected to form a semi-buried groove; after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, the multi-layer core board group is pressed; the multi-layer core board group after the pressing process is drilled so that the multi-layer core board group is formed with a conductive through hole; the multi-layer core board group after the drilling process is metallized; the multi-layer core board group after the metallization process is processed to make a circuit to obtain a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module.

[0053] The preparation process of the circuit board with the above-mentioned embedded copper core aluminum nitride ceramic high heat dissipation module is to perform a first gong cutting process on multiple first core boards so that first through grooves are formed on the multiple first core boards, and then multiple first core boards, multiple second core boards, multiple first PP resin layers, multiple second PP resin layers and third PP resin layers are pre-stacked to obtain a multi-layer core board group, and multiple first through grooves are connected in sequence to form a semi-buried groove, and then the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove and then the multi-layer core board group is pressed to embed the embedded copper core aluminum nitride ceramic high heat dissipation module in the multi-layer core board group. The copper core itself has high thermal conductivity and directly contacts with the components for heat dissipation during subsequent circuit board mounting. The aluminum nitride ceramic not only has high thermal conductivity, but also has electrical insulation performance. The design of embedding the copper core on the aluminum nitride ceramic improves the heat dissipation performance of the circuit board, and the circuit design can also be performed on the aluminum nitride ceramic, so that the circuit board can have high heat dissipation performance while reducing the space occupied by the copper core, thereby improving the flexibility of the circuit board circuit design.

[0054] Furthermore, by drilling the multi-layer core board group, conductive through holes are formed on the multi-layer core board group, and then by metallizing the multi-layer core board group, a copper layer is plated on the hole wall of the conductive through hole to make the multi-layer core boards electrically conductive, and at the same time, the gap between the embedded copper-core aluminum nitride ceramic high heat dissipation module and the multi-layer core board assembly can be filled with copper, thereby improving the bonding stability between the embedded copper-core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, thereby effectively improving the mechanical strength and reliability of the circuit board, and further effectively extending the service life of the circuit board.

[0055] It should be noted that aluminum nitride ceramics have extremely high thermal conductivity (170W / m·K~200W / m·K) and good electrical insulation performance. Embedding aluminum nitride ceramics inside the circuit board can effectively improve the heat dissipation performance of power components while ensuring electrical insulation performance. In addition, since aluminum nitride ceramics have good electrical insulation performance, circuit design can be performed on aluminum nitride ceramics, improving the flexibility of circuit board circuit design. The copper core itself has excellent thermal conductivity (thermal conductivity is about 400W / m·K) and electrical conductivity, and can be used as an efficient conduction path for current, further improving the heat dissipation performance of the circuit board. By embedding the copper core in aluminum nitride ceramics, the heat dissipation performance of the circuit board can be significantly improved while reducing the space occupied by the copper core. The electrical insulation properties of aluminum nitride ceramics are used to increase the space for circuit board circuit design, thereby effectively improving the flexibility of circuit board circuit design.

[0056] See also Figure 1 In order to better understand the preparation process of the circuit board with embedded copper core aluminum nitride ceramic high heat dissipation module disclosed in the present invention, the preparation process of the circuit board with embedded copper core aluminum nitride ceramic high heat dissipation module is further explained as follows:

[0057] A process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to one embodiment includes the following steps:

[0058] S100, obtaining an embedded copper core aluminum nitride ceramic high heat dissipation module, a plurality of first core boards, a plurality of second core boards, a plurality of first PP resin layers, a plurality of second PP resin layers and a third PP resin layer.

[0059] In this embodiment, a copper core is embedded in aluminum nitride ceramic in advance to form an embedded copper core aluminum nitride ceramic high heat dissipation module, where the first core board and the second core board are both single-layer circuit boards, and a combination of multiple core boards forms a multi-layer circuit board.

[0060] S200, performing a first gong cutting process on the plurality of the first core plates, so that the plurality of the first core plates are all formed with a first through groove.

[0061] In this embodiment, a portion of the core board that needs to be embedded with the copper core aluminum nitride ceramic high heat dissipation module is grooved, that is, multiple first core boards are grooved, so that first through grooves of the same size are formed on the multiple first core boards.

[0062] S300, pre-stack the plurality of first core plates, the plurality of second core plates, the plurality of first PP resin layers, the plurality of second PP resin layers and the third PP resin layer to obtain a multi-layer core plate group, and connect the plurality of the first through grooves in sequence to form a semi-buried groove.

[0063] In this embodiment, multiple first core plates, multiple second core plates, multiple first PP resin layers, multiple second PP resin layers and third PP resin layers are pre-stacked, and the first core plates with first through grooves are stacked on the same side, so that a semi-buried groove is formed on one side of the multi-layer core plate group, and the PP resin layer plays the role of bonding and insulation.

[0064] It should be noted that the first PP resin layer has been grooved before the pre-stacking process, so that each PP resin layer is formed with a first penetration opening, and a plurality of first through grooves and a plurality of first penetration openings are alternately connected to form a semi-buried groove.

[0065] S400, after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, the multi-layer core board assembly is pressed together.

[0066] In this embodiment, after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, a pressing process is performed to extrude the first PP resin layer, the second PP resin layer and the third PP resin layer so that the PP resin layer fills the contact surface between the core boards, and at the same time, the adhesive layer of the PP resin layer fills the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, which can not only enhance the bonding strength between the core boards, but also enhance the bonding strength between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, thereby ensuring that the circuit board has good mechanical strength.

[0067] Furthermore, in one embodiment, after the step of laminating the multi-layer core plate assembly, the preparation process further comprises the following steps:

[0068] The surface of the multi-layer core plate group is subjected to a degumming treatment.

[0069] It should be noted that after the multi-layer core panel assembly is pressed, the glue residue overflowing from the PP resin layer will be on the surface of the multi-layer core panel assembly and the embedded copper core aluminum nitride ceramic high heat dissipation module. By performing a degumming treatment on the surface, the surface cleanliness of the multi-layer core panel assembly is ensured. Specifically, the surface of the multi-layer core panel assembly is plasma cleaned with a degumming agent to ensure that there is no glue residue on the surface of the multi-layer core panel assembly. Then, the surface of the multi-layer core panel assembly is washed with water to flush away the degumming agent remaining on the surface of the multi-layer core panel assembly.

[0070] S500, drilling the multi-layer core plate assembly after the pressing process, so that conductive through holes are formed on the multi-layer core plate assembly.

[0071] In this embodiment, after the lamination process, the bonding stability between the multi-layer core boards is effectively improved, and the electrical conductivity between the multi-layer core boards needs to be achieved through conductive through holes. The multi-layer core board group is drilled to form conductive through holes, so that the multi-layer core boards can achieve electrical conductivity through the conductive through holes, ensuring that the circuit boards can be used normally.

[0072] Furthermore, since there are many debris in the multi-layer core panel group after drilling, the debris remaining in the multi-layer core panel group is removed by blowing the multi-layer core panel group after drilling to ensure the surface cleanliness of the multi-layer core panel group.

[0073] Furthermore, since there is moisture in the core board after the multi-layer core board group has gone through the water washing process, if the internal moisture is not removed, it is easy to cause the circuit board to explode, reducing the yield rate of circuit board production. In one embodiment, the multi-layer core board group after the drilling process is dried. By drying the multi-layer core board group, the moisture remaining in the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group and the moisture between the core boards can be effectively removed, avoiding the circuit board from exploding during the back-end process preparation, and further improving the yield rate of the circuit board. Furthermore, the drying temperature is 150°C and the drying time is 4h. Under this drying condition, it is ensured that the PP resin layer will not melt while effectively removing the moisture in the multi-layer core board group, thereby ensuring that the multi-layer core board group remains dry.

[0074] S600, performing metallization treatment on the multi-layer core board assembly after the drilling treatment.

[0075] In this embodiment, the multi-layer core board group is metallized so that the outer surface of the multi-layer core board group and the conductive through-hole are plated with a copper layer, and at the same time, the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group can be filled, and the connection strength between the multi-layer core board group and the embedded copper core aluminum nitride ceramic high heat dissipation module is increased by the copper layer. Further, the metallization treatment can also fill the gap between the copper core and the aluminum nitride ceramic. Specifically, due to the gap between the copper core and the aluminum nitride ceramic, the contact area between the copper core and the aluminum nitride ceramic is reduced. At the same time, there are significant differences in the thermal expansion coefficient, thermal conductivity and mechanical strength of the copper core and the aluminum nitride ceramic. These differences are likely to cause stress concentration on the bonding surface, especially in high-power thermal cycle application environments, the aluminum nitride ceramic structure is prone to fracture, resulting in a decrease in the overall structural strength of the circuit board. The gap between the copper core and the aluminum nitride ceramic is filled by copper plating, which increases the contact area between the copper core and the aluminum nitride ceramic and reduces the stress concentration. This effectively improves the connection strength between the copper core and the aluminum nitride ceramic, and further effectively improves the overall structural strength of the circuit board, thereby extending the service life of the circuit board.

[0076] Furthermore, in one embodiment, the specific operation steps of metallizing the multi-layer core plate group after drilling are as follows:

[0077] Performing copper deposition treatment on the multi-layer core board group;

[0078] The multi-layer core board group after copper plating treatment is subjected to full-board electroplating.

[0079] It should be noted that a thin layer of copper is plated on the surface of the multi-layer core board group and in the conductive through-holes by chemical copper plating, and the thin copper is equivalent to the foundation of the copper layer, ensuring the density of the underlying copper, thereby ensuring that the copper layer has a good conductive effect. At the same time, copper plating can fill the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, as well as the gap between the copper core and the aluminum nitride ceramic, thereby effectively improving the connection strength between the copper core and the aluminum nitride ceramic, and improving the connection strength between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, thereby effectively improving the overall structural strength of the circuit board. Furthermore, the multi-layer core board group after copper plating is subjected to full-board electroplating, that is, the surface copper and hole copper of the multi-layer core board group are thickened by VCP electroplating.

[0080] S700, performing circuit manufacturing processing on the metallized multi-layer core board group to obtain a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein.

[0081] In this embodiment, although the embedded copper core aluminum nitride ceramic high heat dissipation module will occupy the space of the circuit board, since aluminum nitride ceramic has good electrical insulation properties, circuits can be designed on its surface, so that the circuit board can obtain better heat dissipation performance while increasing the space for circuit design, thereby effectively improving the flexibility of the circuit board circuit design.

[0082] In one embodiment, after the step of embedding the embedded copper core aluminum nitride ceramic high heat dissipation module into the semi-buried groove of the multi-layer core board group for pressing, and before drilling the multi-layer core board group after the pressing, the preparation process further includes the following steps:

[0083] A second gong cutting process is performed on the side of the multi-layer core plate group away from the embedded copper core aluminum nitride ceramic high heat dissipation module, so that a functional groove connected to the semi-buried groove is formed on the other side of the multi-layer core plate group.

[0084] It should be noted that the design of the functional slot can not only increase the air contact area between the embedded copper core aluminum nitride ceramic high heat dissipation module and the circuit board, but also provide a fitting surface for the sunken components, saving the space occupied by the circuit board when applied to high-power compact electronic equipment, thereby improving the space utilization of electronic equipment.

[0085] In one embodiment, the specific operation steps of obtaining the embedded copper core aluminum nitride ceramic high heat dissipation module and multiple core boards are:

[0086] First, a copper core block and an aluminum nitride ceramic block are obtained;

[0087] Secondly, the central area of ​​the aluminum nitride ceramic block is cut to form an embedded cavity in the central area of ​​the aluminum nitride ceramic block;

[0088] Next, the copper core block is embedded into the embedded cavity until one side of the copper core block is flush with one side of the aluminum nitride ceramic block, so as to obtain the embedded copper core aluminum nitride ceramic high heat dissipation module;

[0089] Then, a plurality of substrates and a plurality of copper foil layers are obtained;

[0090] Finally, the copper foil layer, the substrate and the copper foil layer are stacked and pressed in a three-layer combination to obtain a plurality of core boards.

[0091] It should be noted that the aluminum nitride ceramic block is cut by cutting the central area thereof, specifically, by a water jet cutting machine. Since the aluminum nitride ceramic block itself is relatively brittle, it is easy to break when processed by a CNC machine tool, while the water jet cutting machine can quickly cut out the embedded cavity in the central area of ​​the aluminum nitride ceramic block, and no thermal effect, deformation, slag or ablation will occur during the water jet cutting process, and the cutting effect is good, that is, the cavity wall of the embedded cavity is relatively smooth, and then the copper core block is embedded in the embedded cavity and squeezed at the same time, so that one side of the copper core block is flush with one side of the aluminum nitride ceramic block. During the extrusion process, the copper core block and the aluminum nitride ceramic block will rub against each other, resulting in a gap between the copper core block and the aluminum nitride ceramic block after assembly. After the metallization treatment, the gap is filled by copper plating to strengthen the connection strength between the copper core block and the aluminum nitride ceramic block, so that the connection strength of the circuit board is effectively improved, and at the same time, the service life of the circuit board is greatly extended, and the circuit board has good heat dissipation performance.

[0092] Furthermore, the water jet cutting machine has a water pressure value of 4000psi to 6000psi. It is understandable that water jet cutting is more stable than CNC machine cutting. Specifically, the aluminum nitride ceramic block itself is relatively brittle. Due to the high hardness of the diamond guillotine, it is easy to cause cracks in the structure of the aluminum nitride ceramic block when it is cut by the diamond guillotine of the CNC machine. Water jet cutting uses high-pressure water, which has good affinity. During water jet cutting, it only acts on the cutting area of ​​the aluminum nitride ceramic block, and no additional forces will be generated on the aluminum nitride ceramic block. The cutting operation can be completed quickly, and the cutting water pressure value is controlled between 4000psi and 6000psi to avoid the collapse of the aluminum nitride ceramic block structure while quickly forming an embedded cavity in the central area of ​​the aluminum nitride ceramic block, which has an excellent cutting effect.

[0093] Furthermore, in the conventional copper block embedding process, if the surface of the copper block is slightly higher than the surface of the circuit board, that is, the copper block protrudes, the etching solution will attack the edge of the copper block in the subsequent etching process, causing a gap to appear at the connection between the copper block and the circuit board, that is, the right angle of the copper block edge becomes blunt, reducing the connection area between the copper block and the circuit board, thereby reducing the connection strength between the copper block and the circuit board, and then reducing the overall structural strength of the circuit board. Therefore, in the conventional copper block embedding process, the flatness requirement is extremely strict, that is, the copper block cannot protrude, but it is difficult to control during the lamination process, and the protruding part is very microscopic, and it is difficult for the operator to observe it with the naked eye, resulting in a low yield rate of the copper block embedded circuit board. However, the design of the embedded copper core aluminum nitride ceramic high heat dissipation module disclosed in the present invention, even if there is a protruding part relative to the surface of the circuit board, the etching solution cannot etch the aluminum nitride ceramic block, reducing the flatness requirement of the embedded copper core aluminum nitride ceramic high heat dissipation module and reducing the operation requirements of the operator, greatly improving the yield rate of the circuit board.

[0094] Furthermore, the flatness between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group is ±50μm. It can be understood that the height difference between the embedded copper core aluminum nitride ceramic high heat dissipation module and the outer core board is controlled between ±50μm, which can ensure that the surface of the circuit board is relatively flat, and can also ensure that the embedded copper core aluminum nitride ceramic high heat dissipation module has a higher contact area with the outer core board, further improving the heat dissipation performance of the circuit board.

[0095] Furthermore, since the first core board and the second core board partially located inside the multilayer circuit board need to be used for inner layer circuit production, in one embodiment, after laminating and pressing the three-layer combination of the copper foil layer, the substrate and the copper foil layer to obtain a plurality of core boards, the preparation process further includes the following steps:

[0096] Inner layer circuit manufacturing is performed on a portion of the first core board and a portion of the second core board.

[0097] It should be noted that the anti-corrosion dry film is attached to the two copper surfaces of the core board by heat pressing, and then the core board is subjected to inner layer exposure treatment, and the image on the original film is transferred to the photosensitive base plate by the light source, and a chemical reaction occurs on the dry film. Then, the core board is subjected to inner layer development treatment, and the part of the dry film that has not undergone a chemical reaction is washed away with alkaline solution to expose the copper surface. Finally, the core board is subjected to inner layer etching treatment, and the copper on the exposed part of the copper surface is etched with chemicals to form inner layer circuits on both sides of the core board.

[0098] Furthermore, the substrate is an FR4 board. It is understandable that the FR4 board is an epoxy glass fiber board, which has good heat resistance and good electrical insulation performance. The FR4 board has good flatness and a smooth surface, which makes the plane consistency of the core board better. At the same time, its excellent heat resistance enables the circuit board to maintain good structural stability in a long-term thermal cycle environment, thereby extending the service life of the circuit board.

[0099] Furthermore, the height of the semi-buried groove is 0.3 to 0.5 times the thickness of the multi-layer core board group after pressing. It is understandable that the height of the embedded copper core aluminum nitride ceramic high heat dissipation module is also 0.3 to 0.5 times the thickness of the multi-layer core board group after pressing. At the same time, since the pressing process is a hot pressing process, it is necessary to melt the PP resin layer to form a cast glue to fill the gap between the core boards and the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group. Therefore, the temperature of the hot pressing process is controlled at 140°C to 225°C, and the pressure of the pressing process is between 100psi and 400psi.

[0100] Furthermore, in order to ensure a better pressing effect, the surface flatness between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group is between ±50μm, and the glue overflow on the surface of the multi-layer core board group is reduced. In this embodiment, by controlling the pressure value and temperature in sections, that is, performing a section-by-section pressing process on the multi-layer core board group, the section-by-section control method can effectively improve the bonding effect between the core boards and the bonding effect between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, and at the same time, the surface flatness of the multi-layer core board group can be increased.

[0101] Furthermore, the specific operation steps of the segmented pressing process are:

[0102] The multi-layer core panel assembly is subjected to the first stage of lamination treatment, with a pressure value of 100 psi, a temperature of 140°C, and a time of 10 minutes;

[0103] The multilayer core panel assembly is subjected to a second stage of pressing, with a pressure value of 200 psi, a temperature of 190°C, and a time of 5 minutes;

[0104] The multi-layer core panel assembly is subjected to the third stage of pressing, with a pressure value of 380 psi, a temperature of 225°C, and a time of 60 minutes;

[0105] The multi-layer core panel assembly is subjected to the fourth stage of pressing treatment, with a pressure value of 200 psi, a temperature of 140° C., and a time of 20 minutes;

[0106] It is understandable that, since the melting point of the PP resin layer is between 164℃ and 170℃, the first lamination process can soften the PP resin layer and slowly extend it, thereby increasing the contact area between the PP resin layer and the two core board layers. Next, the second lamination process increases the pressure and temperature values ​​based on the first lamination process, with the goal of accelerating the arrival of the melting point while the PP resin layer slowly extends. At this point, part of the PP resin layer has slowly begun to fuse, and the PP resin layer has gradually extended during the second lamination process. Then, by increasing the pressure and temperature values, the multi-layer core panel group enters the third stage of pressing treatment. Under the conditions of this third stage of pressing treatment, the PP resin layer is completely melted and quickly cast in the gap between the core panels and the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core panel group, ensuring good bonding between the core panels and between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core panel group. Finally, the multi-layer core panel group is cooled and allowed to stand for 30 minutes to allow the cast PP resin glue to cool and solidify. In this process, not only can the surface flatness between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core panel group be controlled between ±50μm, but also the overflow of glue on the surface of the multi-layer core panel group can be reduced, and even no overflow of glue may occur.

[0107] Furthermore, when the size of the semi-buried slot and the embedded copper core aluminum nitride ceramic high heat dissipation module is fixed, no matter how many multi-layer circuit boards there are, the thickness setting of the PP resin layer and the setting of the core board thickness are key factors affecting the surface glue overflow during the lamination process. In order to further reduce the surface glue overflow of the multi-layer core board group during the lamination process. In one embodiment, the thickness of the core board is detected to simultaneously obtain the thickness of the PP resin layer, and the PP resin layer is laminated with the core board and then lamination is performed in sections to obtain a situation where there is no glue overflow on the surface of the multi-layer core board group, without the need for additional glue removal treatment, thereby simplifying the preparation process of the circuit board and improving the production efficiency of the circuit board.

[0108] Furthermore, the thickness of the core board is detected to simultaneously obtain the thickness of the PP resin layer, including: firstly, establishing a database of multiple core board thicknesses and multiple PP resin layers in one-to-one correspondence; then, the thickness of the core board to be detected is detected to obtain the actual thickness of the core board; then, according to the actual thickness of the core board, the thickness of the PP resin layer corresponding to the thickness of the core board to be detected is retrieved, so as to avoid glue overflow on the surface of the multi-layer core board group, improve the utilization rate of the PP resin layer, and obtain the best pressing effect of the multi-layer core board group. Furthermore, according to this PP resin layer, after being stacked with the core board, a segmented pressing process is performed to obtain a situation where there is no glue overflow on the surface of the multi-layer core board group, and no additional glue removal process is required, which simplifies the preparation process of the circuit board and improves the production efficiency of the circuit board.

[0109] Furthermore, the step of detecting the thickness of the core board is specifically as follows: collecting data on the thickness of the core board through a CCD microscope camera to obtain data on the core board; denoising the data of the core board; fitting the denoised data of the core board to obtain a three-dimensional image of the data of the core board; measuring the data of the core board according to the three-dimensional image of the core board to obtain the thickness of the PP resin layer, thereby improving the accuracy of the detection data of the thickness of the core board and enabling automatic measurement. Furthermore, the step of collecting data on the thickness of the core board through a CCD microscope camera is specifically as follows: scanning the surface of the core board through a CCD microscope camera to obtain a three-dimensional image of the surface of the core board. Furthermore, the step of measuring data on the core board according to the three-dimensional image of the core board is specifically as follows: performing multiple measurements on multiple positions of the core board according to the three-dimensional image of the core board to obtain multiple actual thickness values ​​of the core board; averaging the multiple actual thickness values ​​of the core board to obtain the average actual thickness of the core board. Furthermore, the step of retrieving the thickness of the PP resin layer corresponding to the thickness of the core board to be tested according to the actual thickness of the core board is specifically as follows: retrieving the thickness of the PP resin layer corresponding to the core board to be tested according to the average value of the actual thickness of the core board to match the actual pressing needs of the core board. By averaging the actual thickness of the core board, the data accuracy of the core board is higher, and the multi-layer core board group obtains the best pressing effect. At the same time, there is no glue overflow on the surface, and no additional glue removal treatment is required, which simplifies the preparation process of the circuit board and improves the production efficiency of the circuit board.

[0110] In one embodiment, after the step of obtaining the copper core block and the aluminum nitride ceramic block, and before the step of cutting the central area of ​​the aluminum nitride ceramic block to form an embedded cavity in the central area of ​​the aluminum nitride ceramic block, the preparation process further includes the following steps:

[0111] The copper core block is subjected to surface grinding treatment.

[0112] It should be noted that by grinding the surface of the copper core block to ensure the flatness of the contact surface between the copper core block and the patch component, the mounting effect is enhanced, which can better help the component dissipate heat, so that the circuit board has better heat dissipation performance when used in high-power compact electronic equipment.

[0113] In one embodiment, the specific operation steps of performing the first gong cutting process on the plurality of the first core boards are:

[0114] The first cutting process is performed on the plurality of first core plates by using a CNC machine tool.

[0115] It is understandable that the first through groove can be quickly formed on the core plate by cutting the core plate using a CNC machine tool, and the production cost is not high.

[0116] In one embodiment, the specific operation steps of performing a second gong cutting process on a side of the multi-layer core board assembly away from the embedded copper core aluminum nitride ceramic high heat dissipation module are:

[0117] The CNC machine tool is used to perform a second cutting process on the plurality of second core plates in the multi-layer core plate group.

[0118] It is understandable that by using a CNC machine tool to perform guillotine cutting on a plurality of second core plates in a multi-layer core plate group, functional grooves can be quickly formed on the multi-layer core plate group while the production cost is not high.

[0119] It should be noted that the second cutting process can not only form a second through groove in the second core board, but also form a second through opening in the second PP resin layer and a third through opening in the third PP resin layer, and multiple second through grooves and multiple second through openings are alternately connected to form a functional groove, and the semi-buried groove and the functional groove are connected through the third through opening.

[0120] Furthermore, after the second cutting process is performed on the multiple second core plates in the multi-layer core plate group by the CNC machine tool, the multi-layer core plate group needs to be blown to remove the debris remaining in the multi-layer core plate group to ensure the cleanliness of the multi-layer core plate group.

[0121] In one embodiment, the rotation speed of the first cutting process and the rotation speed of the second cutting process are both 30Krpm to 35Krpm, and the tool speed of the first cutting process and the tool speed of the second cutting process are both 0.1m / min to 0.2m / min. It can be understood that under this cutting condition, the burrs in the first through groove and the functional groove can be reduced, and the flatness of the first through groove and the functional groove can be improved.

[0122] In one embodiment, the specific operation steps of performing circuit manufacturing on the multi-layer core board group after metallization are as follows:

[0123] First, a corrosion-resistant dry film is attached to the surface of the multi-layer core board assembly by heat pressing;

[0124] Secondly, the multi-layer core board group is subjected to an outer layer exposure treatment;

[0125] Then, the multi-layer core board group after the exposure treatment is subjected to an outer layer development treatment;

[0126] Finally, the multi-layer core board group after the development process is subjected to an outer layer etching process.

[0127] It should be noted that the surface of the multi-layer core board group after metallization treatment is covered with copper, and the anti-corrosion dry film is attached to the two outer copper surfaces of the multi-layer core board group by hot pressing, and then the multi-layer core board group is subjected to outer layer exposure treatment, and the image on the original film is transferred to the photosensitive base plate by the action of the light source, and a chemical reaction occurs on the dry film, and then the multi-layer core board group is subjected to outer layer development treatment, and the part of the dry film that has not undergone a chemical reaction is washed away with alkaline solution to expose the copper surface, and finally the multi-layer core board group is subjected to outer layer etching treatment, and the copper on the exposed part of the copper surface is etched with chemicals to form outer layer circuits on both sides of the multi-layer core board group.

[0128] Furthermore, in one embodiment, after the step of performing an outer layer etching process on the multi-layer core board assembly after the development process, the preparation process further comprises the following steps:

[0129] The multi-layer core plate group is subjected to electrical thickening treatment.

[0130] It should be noted that copper is electroplated on the surface of the outer layer circuit to ensure good conductive stability.

[0131] In one embodiment, after the multi-layer core board assembly after the metallization treatment is subjected to circuit manufacturing, the preparation process further comprises the following steps:

[0132] The outer surface of the multi-layer core board group is treated to obtain the circuit board with the copper core aluminum nitride ceramic high heat dissipation module embedded therein.

[0133] It is understandable that before the outer surface treatment of the multi-layer core board group after metallization treatment, the multi-layer core board group needs to be subjected to AOI testing, and the outer circuit of the multi-layer core board group needs to be scanned and tested to screen out boards with poor circuit copper plating effects, such as circuit patterns that will have short circuits or open circuits. Screening out unqualified boards in advance can save the cost of outer surface treatment. Furthermore, by sequentially performing solder mask, character, fine carving and nickel-palladium-gold processing steps on the qualified multi-layer core board group, a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module can be obtained.

[0134] See also Figure 2 The present disclosure also provides a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein, which is prepared by the preparation process of a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein described in any of the above embodiments;

[0135] The circuit board 10 includes a multi-layer core board group 100 and an embedded copper core aluminum nitride ceramic high heat dissipation module 200. The multi-layer core board group 100 is formed with a semi-buried groove 102 and a conductive through hole 104. The embedded copper core aluminum nitride ceramic high heat dissipation module 200 is arranged in the semi-buried groove 102.

[0136] In this embodiment, the circuit board prepared by the preparation process of the circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module not only has good structural strength and heat dissipation performance, but also has more outer layer circuit design space, so that the circuit design of the circuit board 10 is more flexible, especially suitable for high-power compact electronic devices.

[0137] Furthermore, the embedded copper core aluminum nitride ceramic high heat dissipation module 200 is disposed in the semi-buried groove 102 to enhance the heat dissipation performance of the circuit board 10, and the conductive through-holes 104 can connect each core board in series so that each core board is electrically connected through the conductive through-holes 104.

[0138] like Figure 2 As shown, in one embodiment, the multi-layer core plate group includes a first core plate group 110 and a second core plate group 120, the second core plate group 120 is stacked on the first core plate group 110, a semi-buried groove 102 is formed on the first core plate group 110, and a functional groove 106 connected to the semi-buried groove 102 is formed on the second core plate group 120. It can be understood that the semi-buried groove 102 is provided to embed the copper-core aluminum nitride ceramic high heat dissipation module 200 in the multi-layer core plate group to enhance the heat dissipation performance of the multi-layer core plate group, thereby enhancing the heat dissipation performance of the circuit board 10, and the provision of the functional groove 106 can provide more functional component patch space for the circuit board 10 when it is applied to high-power compact electronic devices.

[0139] like Figure 2As shown, in one embodiment, the first core plate group 110 includes a plurality of first core plates 1110 and a plurality of first PP resin layers 1120, the plurality of first core plates 1110 and the plurality of first PP resin layers 1120 are alternately stacked, each of the first core plates 1110 is provided with a first through groove 1112, each of the first PP resin layers 1120 is provided with a first through-hole 1122, and the plurality of first through grooves 1112 and the plurality of first through-holes 1122 are alternately connected to form the semi-buried groove 102. It can be understood that the first core plates 1110 are bonded and electrically insulated by the first PP resin layer 1120, and the plurality of first through grooves 1112 and the plurality of first through-holes 1122 are alternately connected to form the semi-buried groove 102, so that the embedded copper core aluminum nitride ceramic high heat dissipation module 200 can be buried to enhance the heat dissipation performance of the circuit board 10.

[0140] like Figure 2 As shown, in one embodiment, the second core plate group 120 includes a plurality of second core plates 1210 and a plurality of second PP resin layers 1220, the plurality of second core plates 1210 and the plurality of second PP resin layers 1220 are alternately stacked, each of the second core plates 1210 is provided with a second through-groove 1212, each of the second PP resin layers 1220 is provided with a second through-hole 1222, and the plurality of second through-grooves 1212 and the plurality of second through-holes 1222 are alternately connected to form the functional groove 106. It can be understood that the second core plates 1210 are bonded and electrically insulated by the second PP resin layers 1220, and by alternately connecting the plurality of second through-grooves 1212 and the plurality of second through-holes 1222 to form the functional groove 106, more functional element patch space can be provided for the circuit board 10 when it is applied to high-power compact electronic devices.

[0141] like Figure 2 As shown, in one embodiment, the circuit board 10 further includes a third PP resin layer, which is disposed between the first core plate group 110 and the second core plate group 120, and the third PP resin layer is provided with a third penetration opening 302, and the semi-buried groove 102 and the functional groove 106 are connected through the third penetration opening 302. It can be understood that the first core plate group 110 and the second core plate group 120 are bonded and electrically insulated by the third PP resin layer.

[0142] like Figure 2As shown, in one embodiment, the embedded copper core aluminum nitride ceramic high heat dissipation module 200 includes a copper core block 210 and an aluminum nitride ceramic block 220, the aluminum nitride ceramic block 220 is provided with an embedded cavity 222, and the copper core block 210 is embedded in the embedded cavity 222. It can be understood that the design of placing the inner cavity of the copper core block 210 in the aluminum nitride ceramic block 220 can not only enhance the heat dissipation performance of the circuit board 10, but also provide more space for the circuit design of the circuit board 10, thereby improving the flexibility of the circuit design of the circuit board 10.

[0143] For further information, see Figure 2 In one embodiment, the embedded cavity 222 is a through cavity, that is, both sides of the copper core block 210 can contact the patch components, so that the circuit board 10 has excellent heat dissipation performance, especially for use in high-power compact electronic devices. Further, one side of the copper core block 210 is flush with the aluminum nitride ceramic block 220, and the other side of the copper core block 210 is not flush with the aluminum nitride ceramic block 220, that is, a groove is cut on the copper core block 210, so that the other side of the copper core block 210 is concave relative to the aluminum nitride ceramic block 220, which can provide more patch space for sunken patch components, and can also save space for the circuit board 10 when applied to high-power compact electronic devices, providing feasibility for the diversification of functions of high-power compact electronic devices.

[0144] Furthermore, since the thermal conductivity of the aluminum nitride ceramic block 220 and the copper core block 210 is very different, although the horizontal expansion of the copper core block 210 can be suppressed by embedding, the vertical expansion still exists. In a long-term thermal cycle environment, the copper core block 210 is more likely to expand, causing the embedded copper core aluminum nitride ceramic high heat dissipation module 200 to collapse in the vertical direction. Figure 3 As shown, in another embodiment, one side of the copper core block 210 is in contact with the bottom of the embedded cavity 222, and the other side of the copper core block 210 is flush with the aluminum nitride ceramic block 220. Although a portion of the heat dissipation performance will be lost, the structural stability of the embedded copper core aluminum nitride ceramic high heat dissipation module 200 is further enhanced. Specifically, the thermal expansion of the copper core block 210 in the horizontal and vertical directions is slowed down by the enclosure of the aluminum nitride ceramic block 220. In a long-term thermal cycle environment, the embedded copper core aluminum nitride ceramic high heat dissipation module 200 can maintain good structural stability, thereby effectively extending the service life of the circuit board 10.

[0145] Examples are listed below, but it should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial channels unless otherwise specified.

[0146] Example 1

[0147] 1. Obtain an embedded copper core aluminum nitride ceramic high heat dissipation module, a plurality of first core boards, a plurality of second core boards, a plurality of first PP resin layers, a plurality of second PP resin layers and a third PP resin layer. Specifically, obtain a copper core block and an aluminum nitride ceramic block, cut the central area of ​​the aluminum nitride ceramic block to form an embedded cavity in the central area of ​​the aluminum nitride ceramic block, grind the surface of the copper core block, and embed the copper core block into the embedded cavity until one side of the copper core block is flush with one side of the aluminum nitride ceramic block to obtain an embedded copper core aluminum nitride ceramic high heat dissipation module; obtain a plurality of substrates, a plurality of copper foil layers, a plurality of first PP resin layers and a plurality of second PP resin layers, and stack and press them in a three-layer combination of copper foil layers, substrates and copper foil layers to obtain a plurality of first core boards and a plurality of second core boards;

[0148] 2. Performing a first gong cutting process on the plurality of first core plates, so that the plurality of first core plates are all formed with first through grooves, the rotation speed of the first gong cutting process is 34Krpm, and the cutting speed is 0.1m / min;

[0149] 3. Stacking a plurality of first core plates and a plurality of first PP resin layers in the order of the first core plate, the first PP resin layer and the first core plate to obtain a first core plate group, and connecting a plurality of first through grooves in sequence to form a semi-buried groove; stacking a plurality of second core plates and a plurality of second PP resin layers in the order of the second core plate, the second PP resin layer and the second core plate to obtain a second core plate group; stacking the second core plate group on the first core plate group, and placing the third PP resin layer between the first core plate group and the second core plate group to obtain a multi-layer core plate group;

[0150] 4. After the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, the multi-layer core board group is pressed at a pressure of 380 psi, a pressing temperature of 225°C, and a pressing time of 60 minutes;

[0151] 5. Remove glue from the multi-layer core board group;

[0152] 6. Perform a second cutting process on the side of the multi-layer core board assembly that is away from the embedded copper core aluminum nitride ceramic high heat dissipation module. The speed of the second cutting process is 34Krpm, and the cutting speed is 0.1m / min.

[0153] 7. Drilling the multi-layer core board assembly to form conductive through holes on the multi-layer core board assembly;

[0154] 8. Metallization treatment of the multi-layer core board group;

[0155] 9. Carry out circuit processing on the multi-layer core board group;

[0156] 10. Perform outer surface treatment on the multi-layer core board group to obtain a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module.

[0157] Example 2

[0158] The difference from Example 1 is that after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, the multi-layer core board group is subjected to segmented pressing treatment. Specifically, the multi-layer core board group is subjected to the first segment pressing treatment, the pressure value is 100psi, the temperature is 140°C, and the time is 10min; the multi-layer core board group is subjected to the second segment pressing treatment, the pressure value is 200psi, the temperature is 190°C, and the time is 5min; the multi-layer core board group is subjected to the third segment pressing treatment, the pressure value is 380psi, the temperature is 225°C, and the time is 60min; the multi-layer core board group is subjected to the fourth segment pressing treatment, the pressure value is 200psi, the temperature is 140°C, and the time is 20min;

[0159] Delete step 5.

[0160] Example 3

[0161] The difference from Example 1 is that the pressing time is 90 minutes.

[0162] The glue overflow during the lamination process was observed, and the surface flatness of the circuit board after preparation was measured. The results are shown in Table 1.

[0163] Table 1

[0164] Surface glue overflow Surface flatness Example 1 There is local glue residue -26μm Example 2 No glue residue 5μm Example 3 There is more glue residue 40μm

[0165] It can be seen from Table 1 that the surface flatness of the circuit boards obtained by using the preparation process of the circuit boards with embedded copper core aluminum nitride ceramic high heat dissipation modules disclosed in the present invention meets the requirements, that is, the yield rate of the circuit boards is relatively high.

[0166] By comparing Example 1 and Example 3, excessive lamination will cause serious glue overflow. By comparing Examples 1-3, reasonable segmented lamination can avoid glue overflow during lamination, improve the utilization rate of the PP resin layer, eliminate the need for additional glue removal, simplify the preparation process of the circuit board, and improve the production efficiency of the circuit board.

[0167] Compared with the prior art, the present invention has at least the following advantages:

[0168] 1. Performing a first gong cutting process on a plurality of first core boards, so that a first through groove is formed on each of the plurality of first core boards, and then performing a pre-stacking process on the plurality of first core boards, the plurality of second core boards, the plurality of first PP resin layers, the plurality of second PP resin layers and the third PP resin layer to obtain a multi-layer core board group, and the plurality of first through grooves are sequentially connected to form a semi-buried groove, and then the multi-layer core board group is pressed after the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried groove, so that the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the multi-layer core board group, the copper core itself has high thermal conductivity, and directly contacts with the components for heat dissipation during subsequent circuit board mounting, and the aluminum nitride ceramic not only has high thermal conductivity, but also has electrical insulation performance, and the design of the copper core embedded in the aluminum nitride ceramic improves the heat dissipation performance of the circuit board, and the circuit design can also be performed on the aluminum nitride ceramic, so that the circuit board can have a high heat dissipation performance while reducing the space occupied by the copper core, thereby improving the flexibility of the circuit board circuit design.

[0169] 2. Conductive through holes are formed on the multi-layer core board group by drilling the multi-layer core board group, and then a copper layer is plated on the hole wall of the conductive through hole by metallizing the multi-layer core board group to make the multi-layer core boards electrically conductive. At the same time, the gap between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board assembly can be filled with copper, thereby improving the bonding stability between the embedded copper core aluminum nitride ceramic high heat dissipation module and the multi-layer core board group, thereby effectively improving the mechanical strength and reliability of the circuit board, and further effectively extending the service life of the circuit board.

[0170] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module, characterized in that: The steps include: Obtain an embedded copper core aluminum nitride ceramic high heat dissipation module, a plurality of first core boards, a plurality of second core boards, a plurality of first PP resin layers, a plurality of second PP resin layers and a third PP resin layer; Performing a first gong cutting process on the plurality of the first core plates, so that the plurality of the first core plates are all formed with a first through groove; Pre-stacking a plurality of the first core plates, a plurality of the second core plates, a plurality of the first PP resin layers, a plurality of the second PP resin layers and the third PP resin layer to obtain a multi-layer core plate group, and connecting a plurality of the first through grooves in sequence to form a semi-buried groove; After the embedded copper core aluminum nitride ceramic high heat dissipation module is embedded in the semi-buried slot, the multi-layer core board assembly is pressed together; Performing drilling processing on the multi-layer core plate group after the pressing processing, so that the multi-layer core plate group is formed with conductive through holes; Performing metallization treatment on the multi-layer core plate group after the drilling treatment; The multi-layer core board group after metallization treatment is subjected to circuit manufacturing treatment to obtain a circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein.

2. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 1, characterized in that: After the step of embedding the embedded copper core aluminum nitride ceramic high heat dissipation module into the semi-buried groove of the multi-layer core board group for pressing, and before drilling the multi-layer core board group after the pressing, the following steps are also included: A second gong cutting process is performed on the side of the multi-layer core plate group away from the embedded copper core aluminum nitride ceramic high heat dissipation module, so that a functional groove connected to the semi-buried groove is formed on the other side of the multi-layer core plate group.

3. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 1, characterized in that: The specific operation steps of obtaining the embedded copper core aluminum nitride ceramic high heat dissipation module and multiple core boards are as follows: obtaining a copper core block and an aluminum nitride ceramic block; Cutting the central area of ​​the aluminum nitride ceramic block so that an embedded cavity is formed in the central area of ​​the aluminum nitride ceramic block; Embedding the copper core block into the embedded cavity until one side of the copper core block is flush with one side of the aluminum nitride ceramic block, so as to obtain the embedded copper core aluminum nitride ceramic high heat dissipation module; Obtaining a plurality of substrates, a plurality of copper foil layers, a plurality of the first PP resin layers, and a plurality of the second PP resin layers; The copper foil layer, the substrate and the copper foil layer are stacked and pressed in a three-layer combination to obtain a plurality of the first core boards and a plurality of the second core boards.

4. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 1, characterized in that: The specific operation steps of pre-stacking the plurality of first core plates, the plurality of second core plates, the plurality of first PP resin layers and the plurality of second PP resin layers are: stacking a plurality of the first core panels and a plurality of the first PP resin layers in the order of the first core panels, the first PP resin layers, and the first core panels to obtain a first core panel group; stacking a plurality of the second core plates and a plurality of the second PP resin layers in the order of the second core plates, the second PP resin layers and the second core plates to obtain a second core plate group; The second core plate group is stacked on the first core plate group, and the third PP resin layer is placed between the first core plate group and the second core plate group to obtain the multi-layer core plate group.

5. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 2, characterized in that: The specific operation steps of performing the first gong cutting process on the plurality of the first core plates are: The first cutting process is performed on the plurality of first core plates by using a CNC machine tool.

6. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 5, characterized in that: The specific operation steps of performing the second gong cutting process on the side of the multi-layer core board assembly away from the embedded copper core aluminum nitride ceramic high heat dissipation module are as follows: The CNC machine tool is used to perform a second cutting process on the plurality of second core plates in the multi-layer core plate group.

7. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 6, characterized in that: The rotation speed of the first cutting process and the rotation speed of the second cutting process are both 30Krpm to 35Krpm; The tool speed of the first cutting process and the tool speed of the second cutting process are both 0.1 m / min to 0.2 m / min.

8. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 1, characterized in that: The specific operation steps of performing circuit manufacturing on the multi-layer core board group after metallization treatment are as follows: Affixing the anti-corrosion dry film to the surface of the multi-layer core plate assembly by heat pressing; Performing an outer layer exposure treatment on the multi-layer core board group; Performing outer layer development treatment on the multi-layer core board group after the exposure treatment; The multi-layer core board group after the development treatment is subjected to an outer layer etching treatment.

9. The process for preparing a circuit board with an embedded copper core aluminum nitride ceramic high heat dissipation module according to claim 1, characterized in that: After the multi-layer core board group after the metallization process is subjected to circuit manufacturing process, the following steps are also included: The outer surface of the multi-layer core board group is treated to obtain the circuit board with the copper core aluminum nitride ceramic high heat dissipation module embedded therein.

10. A circuit board with a copper core aluminum nitride ceramic high heat dissipation module embedded therein, characterized in that: The circuit board is prepared by the preparation process of the circuit board with embedded copper core aluminum nitride ceramic high heat dissipation module according to any one of claims 1 to 9; The circuit board comprises a multi-layer core board group and an embedded copper core aluminum nitride ceramic high heat dissipation module, wherein the multi-layer core board group is formed with a semi-buried groove and a conductive through hole, and the embedded copper core aluminum nitride ceramic high heat dissipation module is arranged in the semi-buried groove.

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