Power device embedded circuit board integrated with ceramic plate and preparation method thereof

Abstract

The invention relates to the technical field of automobiles and industrial electronics, in particular to a power device embedded circuit board integrated with a ceramic plate and a preparation method of the power device embedded circuit board, and the power device embedded circuit board comprises the ceramic plate, a power device, a conductor layer, an insulating layer, a metal conduction blind hole, a bottom copper plating layer, an assembly welding layer and a blind groove. Compared with a traditional power module, the switching speed is higher, the switching loss is smaller, and the design is more flexible; compared with a power device embedded circuit board in the market, the circuit board has the advantages of lower thermal resistance, lower temperature rise and higher current output capability. The advantages of a traditional power module and an embedded circuit board are integrated, switching loss is small, thermal resistance is small, and the current output capacity can be greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles and industrial electronics, and in particular to a power device embedded circuit board with an integrated ceramic board and a preparation method thereof. Background Art

[0002] With the development and popularization of new energy vehicles and high-power industrial electronics, the importance of motor controllers as the core components of electric drives continues to increase. Traditional motor controller design ideas can no longer meet the increasing demand for usage, and performance is gradually encountering bottlenecks. With the continuous development of third-generation semiconductors SiC and GaN, the requirements for motor controller power density, integration and reliability are getting higher and higher.

[0003] The power module of a traditional motor controller is based on soldering the power device onto a ceramic substrate, then soldering the power module onto a heat sink, and conducting the circuit through bonding wires. At the same time, a circuit board with drive and control functions is designed, and a connector is used to connect the circuit board and the power module to realize its functions. This approach results in high parasitic inductance, large switching losses, large thermal resistance, many production links, complex back-end assembly processes, questionable reliability, and large quality and size.

[0004] To solve the above problems, many advanced packaging solutions are to bury power devices in circuit boards, conduct electricity between circuit layers through blind holes, and then conduct heat through insulating high thermal conductivity materials. Although this solution solves the problems of high parasitic inductance, high loss, large mass, large volume and questionable reliability, it still has the problem of high thermal resistance. Summary of the invention

[0005] The object of the present invention is to provide a power device embedded circuit board with integrated ceramic board and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A power device embedded circuit board with integrated ceramic board, comprising: a ceramic board, a power device, a conductor layer, an insulating layer, and a metal conduction blind hole; The top surface of the ceramic plate is provided with circuits and pits, and the bottom surface is provided with a bottom copper plating layer for heat conduction; The power device is mounted in the recess of the ceramic plate; The conductor layer is stacked on the insulating layer to form a prefabricated board, the prefabricated board is pressed onto the ceramic board, and the power device is connected to the conductor layer through a metal conduction blind hole opened on the prefabricated board.

[0007] Preferably, the mounting method of the power device and the ceramic plate includes but is not limited to silver sintering, copper sintering, and diffusion welding.

[0008] Preferably, the power device includes but is not limited to Si MOSFET, SiC MOSFET, Si IGBT, and GaNMOSFET.

[0009] Preferably, the electrical performance of the power device is achieved through metal conductive blind vias and a conductor layer, and the conductor layer is led out from the bottom copper-plated layer.

[0010] Preferably, one or more power devices are mounted on the ceramic plate via pits.

[0011] Preferably, a bottom copper plating layer is fixed to the bottom of the ceramic board, and the bottom of the ceramic board is fixedly connected to the bottom conductor layer of the circuit board via the bottom copper plating layer.

[0012] Preferably, a blind fishing groove is provided on the top of the prefabricated board.

[0013] The present invention also provides a preparation method for preparing the power device embedded circuit board of the integrated ceramic board, comprising the following steps: S1, manufacturing circuits and pits from ceramic plate raw materials according to the design to form a ceramic plate; S2, placing the power device into the pit of the ceramic plate to form a pre-package, wherein at least one pit is provided in a ceramic plate, and a power device is placed in each pit; S3, etching the circuits on the prefabricated board consisting of the conductor layer and the insulation layer according to the design, and making empty grooves in the prefabricated board to form a semi-finished product 1; S4, put the pre-package into the empty slot of the semi-finished product 1, stack the FR4 prepreg and the copper sheet on it, and press them together to produce the semi-finished product 2. At this time, the copper sheet becomes a new conductor layer, and the FR4 prepreg becomes a new insulation layer; S5, laser-printing a blind hole in the semi-finished product 2 according to the design to form a semi-finished product 3; S6, copper-plating the blind holes in the semi-finished product three to form metal-conducting blind holes. Since the bottom material of the ceramic board is copper, during the copper plating process, the copper at the bottom of the ceramic board will be connected with the copper plating to form a bottom copper plating layer, and then the circuit is etched out according to the design to form a semi-finished product four; S7, continue to stack FR4 prepreg and copper foil on semi-finished product 4 for second lamination. After lamination, FR4 prepreg becomes a new insulating layer, copper foil becomes a new conductor layer, and then blind holes are made on the top surface and copper is plated to form metal conduction blind holes. The bottom copper plating layer of the bottom of the ceramic board continues to thicken during this process, and then the circuit is etched on the top conductor layer to form semi-finished product 5; S8. Based on the semi-finished product five, print the solder mask according to the design, make blind grooves selectively, and do surface treatment, and then cut the board into the required size to form a finished board.

[0014] Preferably, in step S4, multiple semi-finished products 1 are selected for pressing and pre-packaging and placed in the empty slot of each semi-finished product 1.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. High degree of integration. The invention can integrate power devices, drive devices and power copper terminals into one; 2. Reduce switching loss. The parasitic inductance of the invention can be reduced to below 2nH, thereby significantly reducing switching loss; 3. Low thermal resistance. The thermal resistance of the invention can be reduced to below 0.2℃ / W. Under the same loss, the temperature rise is lower; 4. Strong current output capability. After the switching loss and thermal resistance are reduced, the current output capability can be greatly improved; 5. High reliability. All production processes of this solution are traditional and mature processes, which reduces additional processes, reduces production difficulty and improves reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the manufacturing and structure of the ceramic plate of the present invention; Figure 3 This is a schematic diagram of the pre-packaging of the present invention; Figure 4 This is a production and structural diagram of a semi-finished product of the present invention; Figure 5 This is a production and structural diagram of the semi-finished product 2 of the present invention; Figure 6 This is a schematic diagram of the third structure of the semi-finished product of the present invention; Figure 7 This is a schematic diagram of the structure of the semi-finished product 4 of the present invention; Figure 8 This is a schematic diagram of the production and structure of the semi-finished product 5 of the present invention; Fig. 9 This is a schematic diagram of the finished product structure of the present invention; Fig.10 It is a simulation diagram of heat distribution during operation of a circuit board in the prior art; Fig.11 This is a simulation diagram of heat distribution when the circuit board of the present invention is in operation.

[0017] In the figure: 1. Ceramic board; 2. Power device; 3. Conductor layer; 4. Insulation layer; 5. Metal via blind hole; 6. Bottom copper plating layer; 7. Solder mask layer; 8. Blind groove. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, a power device embedded circuit board with integrated ceramic board includes: a ceramic board 1, a power device 2, a conductor layer 3, an insulating layer 4, and a metal conductive blind hole 5; The top surface of the ceramic plate 1 is provided with circuits and pits, and the bottom surface is provided with a bottom copper-plated layer 6 for heat conduction; The power device 2 is mounted in the recess of the ceramic plate 1; The conductor layer 3 is stacked on the insulating layer 4 to form a prefabricated board, the prefabricated board is pressed on the ceramic board 1, and the power device 2 is connected to the conductor layer 3 through the metal conductive blind hole 5 opened on the prefabricated board.

[0020] Specifically, the mounting methods of the power device 2 and the ceramic board 1 include, but are not limited to, silver sintering, copper sintering, and diffusion welding.

[0021] Specifically, the power device 2 includes but is not limited to Si MOSFET, SiC MOSFET, Si IGBT, and GaN MOSFET.

[0022] Specifically, the electrical performance of the power device 2 is achieved through the metal conductive blind via 5 and the conductor layer 3 , and the heat generated by the conductor layer 3 is conducted away from the bottom copper plating layer 6 through the ceramic board 1 .

[0023] Specifically, a plurality of power devices 2 are mounted on the ceramic board 1 through pits.

[0024] Specifically, the bottom of the ceramic board 1 is fixedly connected to the bottom conductor layer of the circuit board via the bottom copper plating layer 6 .

[0025] Specifically, a blind fishing groove 8 is provided on the top of the prefabricated board.

[0026] Furthermore, it should be noted that: The power device embedded circuit board of the integrated ceramic board is a circuit board with multiple conductor layers 3, and the layers are filled with insulating materials. The power device 2 is placed in the pit of the ceramic board, and the ceramic board is placed in the circuit board; The power device 2 is embedded in the circuit board body through the circuit board manufacturing process. The electrical performance of the power device 2 is realized through the metal conductive blind hole 5 and the conductor layer 3. The main heat is conducted out through the ceramic board 1 and the bottom copper plating layer 6. The present invention first combines the power device 2 in the ceramic plate pit, and the combination method includes but is not limited to sintering silver, sintering copper and diffusion welding, and then the ceramic plate 1 is placed in the circuit board. The number of pits in the ceramic plate can be single or multiple according to the design, and each pit has at least one chip; The main body of the present invention is a circuit board, which can be a single-layer circuit board, a double-layer circuit board, a three-layer circuit board, or a circuit board of any layer; The present invention can selectively integrate and embed the power copper terminal (copper block) in the circuit board; Compared with traditional module packaging, the present invention has small parasitic inductance, fast switching speed and small switching loss. Compared with many advanced packaging that bury power devices in circuit boards, the present invention has smaller thermal resistance, smaller temperature rise and greater current output capacity.

[0027] The present invention is based on the traditional circuit board process, integrating power devices, control circuits, drive circuits and copper terminals together, and has the advantages of high degree of integration, fewer production links, short current path, small parasitic inductance, small switching loss, small thermal resistance, high integration, good reliability, and small size and mass.

[0028] The present invention also provides a preparation method, such as Figure 2-9 As shown, the method for preparing the power device embedded circuit board of the integrated ceramic board includes the following steps: S1, manufacturing circuits and pits from ceramic plate raw materials according to the design to form a ceramic plate 1; S2, placing the power device 2 into the pit of the ceramic plate 1 and combining them to form a pre-package. A ceramic plate 1 may have one or more pits, and correspondingly, one or more power devices 2 need to be placed in each pit; S3, etching the circuits on the core board composed of the conductor layer 3 and the insulation layer 4 according to the design, and making empty grooves in the core board to form a semi-finished product 1; S4, placing the pre-package into the empty slot of the semi-finished product 1, stacking the FR4 prepreg and the copper sheet on top, and pressing them together to produce the semi-finished product 2. At this time, the copper sheet becomes the conductor layer 3, and the FR4 prepreg becomes the insulating layer 4. This process can be selectively pressed with one or more semi-finished products 1 according to the design; S5, laser-printing a blind hole in the semi-finished product 2 according to the design to form a semi-finished product 3; S6, copper plating is performed on the semi-finished product 3 to form a metal conductive blind hole 5. Since the bottom material of the ceramic board 1 is copper, during the copper plating process, the copper on the bottom of the ceramic board 1 will be connected with the copper plating to form a bottom copper plating layer 6, and then the circuit is etched out according to the design to form a semi-finished product 4; S7, continue to stack FR4 prepreg and copper foil on the semi-finished product 4 for a second lamination. After the lamination, the FR4 prepreg becomes the insulating layer 4, and the copper foil becomes the conductor layer 3. Then, blind holes are made on the top surface and copper is plated to form metal conduction blind holes 5. The bottom copper plating layer of the bottom of the ceramic board 1 continues to thicken during this process, and then the circuit is etched on the top conductor layer 3 to form a semi-finished product 5; S8. On the basis of the semi-finished product 5, print the solder mask layer 7 according to the design, selectively make blind grooves 8, and perform surface treatment, and then cut the board into the required size to form a finished board.

[0029] like Fig.10 The figure shows a heat distribution simulation diagram of the circuit board in the prior art. According to the simulation results shown in the figure, it is not difficult to see that the maximum temperature of the chip is 131.1°C; the thermal resistance of thermal conductivity = 0.39°C / W; and the total thermal resistance = 0.711°C / W. Fig.11 The figure shows the heat distribution simulation diagram of the circuit board of the present invention during operation. According to the simulation results shown in the figure, it is not difficult to see that the maximum temperature of the chip is 102.0℃; thermal resistance = 0.134℃ / W; total thermal resistance = 0.419℃ / W. Therefore, the circuit board produced and prepared according to the present invention has small switching loss, the parasitic inductance can be reduced to below 2nH, and the switching loss is reduced; the thermal resistance is low, and the thermal resistance can be reduced to below 0.2℃ / W. Under the same loss, the temperature rise is lower; the current output capacity is strong, and the current output capacity can be greatly improved after the switching loss and thermal resistance are reduced; the production difficulty is reduced, and the reliability of the power device embedded circuit board is improved.

[0030] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A power device embedded circuit board with integrated ceramic board, characterized in that: include: Ceramic board (1), power device (2), conductor layer (3), insulating layer (4), metal conduction blind hole (5); The top surface of the ceramic plate (1) is provided with circuits and pits, and the bottom surface is provided with a bottom copper-plated layer (6) for heat conduction; The power device (2) is mounted in the recess of the ceramic plate (1); The conductor layer (3) is stacked on the insulating layer (4) to form a prefabricated plate, the prefabricated plate is pressed onto the ceramic plate (1), and the power device (2) is connected to the conductor layer (3) via a metal conductive blind hole (5) provided on the prefabricated plate.

2. The method for preparing a power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: The mounting method of the power device (2) and the ceramic plate (1) includes, but is not limited to, silver sintering, copper sintering, and diffusion welding.

3. The power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: The power device (2) includes but is not limited to Si MOSFET, SiC MOSFET, Si IGBT, and GaN MOSFET.

4. The power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: The electrical performance of the power device (2) is achieved through the metal conductive blind hole (5) and the conductor layer (3), and the heat generated by the conductor layer (3) is conducted away from the bottom copper-plated layer (6) through the ceramic plate (1).

5. The power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: One or more power devices (2) are mounted on the ceramic plate (1) via pits.

6. The power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: A bottom copper-plated layer (6) is fixed to the bottom of the ceramic plate (1), and the bottom of the ceramic plate (1) is fixedly connected to the bottom conductor layer (3) of the circuit board via the bottom copper-plated layer (6).

7. The power device embedded circuit board with integrated ceramic board according to claim 1, characterized in that: A blind fishing groove (8) is provided on the top of the prefabricated plate.

8. A preparation method for preparing a power device embedded circuit board with an integrated ceramic board as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1, manufacturing circuits and pits from ceramic plate raw materials according to the design to form a ceramic plate (1); S2, placing the power device (2) into a recess of the ceramic plate (1) to form a pre-package, wherein at least one recess is provided in a ceramic plate (1), and a power device (2) is placed in each recess; S3, etching the circuits in the prefabricated plate composed of the conductor layer (3) and the insulating layer (4) according to the design, and making empty grooves in the prefabricated plate to form a semi-finished product 1; S4, placing the pre-package into the empty slot of the semi-finished product 1, stacking the FR4 prepreg and the copper sheet on top, and pressing them together to produce the semi-finished product 2. At this time, the copper sheet becomes a new conductor layer (3), and the FR4 prepreg becomes a new insulation layer (4); S5, laser-printing a blind hole in the semi-finished product 2 according to the design to form a semi-finished product 3; S6, copper-plating the blind holes in the semi-finished product three to form metal conductive blind holes (5). Since the bottom material of the ceramic plate (1) is copper, during the copper plating process, the copper on the bottom of the ceramic plate (1) will be connected with the copper plating to form a bottom copper plating layer (6). Then, the circuit is etched out according to the design to form a semi-finished product four. S7, continue to stack FR4 prepreg and copper foil on semi-finished product four for a second lamination. After lamination, the FR4 prepreg becomes a new insulating layer (4), and the copper foil becomes a new conductor layer (3). Then, blind holes are made on the top surface and copper is plated to form metal conductive blind holes (5). The bottom copper plating layer of the bottom of the ceramic board (1) continues to thicken during this process, and then the top conductor layer (3) is etched to form semi-finished product five; S8. Based on the semi-finished product 5, a solder mask layer (7) is printed according to the design, a blind groove (8) is selectively made, and surface treatment is performed, and then the board is cut into the required size to form a finished board.

9. The preparation method according to claim 8, characterized in that: In step S4, a plurality of semi-finished products 1 are selected for pressing and the pre-packaged products are placed in the empty slots of each semi-finished product 1.

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