Double-sided temperature sensing type strong-current high-voltage PCB (printed circuit board) and manufacturing method thereof

Abstract

The invention discloses a double-sided temperature-sensing type strong-current high-voltage PCB (printed circuit board) and a manufacturing method thereof, and the PCB comprises an organic insulating substrate which is provided with a first surface and a second surface which are oppositely arranged, and is internally provided with at least one embedded cavity penetrating through the thickness of the organic insulating substrate in advance; the at least one double-sided temperature sensing ceramic sensing unit is fixedly embedded in the embedding cavity, and the thickness direction of the double-sided temperature sensing ceramic sensing unit is consistent with that of the organic insulating substrate; and each double-sided temperature-sensing ceramic sensing unit comprises a ceramic insulating body, a temperature sensor, a conductive interconnection structure and a metal circuit layer. According to the invention, the prefabricated double-sided temperature-sensing ceramic sensing unit is embedded in the organic insulating substrate, so that the heat transfer path is effectively shortened, and the thermal resistance of the organic adhesive layer is eliminated; the junction temperature of the double-sided power device of the PCB can be accurately detected, the working stability of the PCB under severe working conditions is ensured, and the core contradiction between high-voltage insulation and reliable integration of heterogeneous materials is solved.

Description

Technical Field

[0001] This invention relates to the field of PCB circuit board technology, and in particular to a double-sided temperature-sensing high-voltage PCB circuit board and its manufacturing method. Background Technology

[0002] In existing technology, PCBs, also known as printed circuit boards, provide electrical connections for electronic components. Their development has a history of over 100 years. Their design primarily involves layout design. The main advantages of using PCBs are significantly reduced wiring and assembly errors, improved automation levels, and increased production efficiency. Based on the number of layers, they can be classified as single-sided, double-sided, four-layer, six-layer, and other multi-layer PCBs. Double-sided PCBs are a very important type of PCB. The market offers double-sided metal-based PCBs, Hi... Heavy copper foil PCBs, flat and curved double-sided PCBs, high-frequency PCBs, and hybrid dielectric base high-frequency double-sided PCBs are suitable for a wide range of high-tech industries such as telecommunications, power supply, computers, industrial control, digital products, scientific and educational instruments, medical devices, automobiles, aerospace, and defense. Existing high-voltage PCBs operate in high-temperature environments, and temperature significantly impacts their performance. To control performance, real-time temperature monitoring using temperature sensors is necessary. These sensors are typically placed on the PCB surface for temperature detection. However, in high-temperature environments, the temperature sensors may deviate in detecting the temperature on both sides of a double-sided PCB, affecting the PCB's operability and usability.

[0003] Chinese utility model patent application number 202221851065.3 discloses a double-sided thick copper high-voltage PCB circuit board, including a component panel, a lead soldering panel, fixing holes, insertion holes, pads, slots, a first support strip, a second support strip, and pad slots. The fixing holes, insertion holes, first support strip, and second support strip are symmetrically positioned on the surfaces of the component panel and the lead soldering panel, respectively. Pads are provided at the outer ends of the insertion holes on both the component panel and the lead soldering panel, and slots are provided inside the insertion holes on both the component panel and the lead soldering panel. The first support strip and the second support strip are symmetrically positioned between the diode and color-ring resistor insertion holes. However, this double-sided thick copper high-voltage PCB circuit board requires a temperature sensor to be mounted on the surface of the PCB circuit board. Heat must be transferred through multiple layers of material, resulting in a long heat transfer path. This makes it impossible to reflect the true junction temperature of the power chip, and it is easily affected by external environmental factors, making accurate temperature detection impossible. Summary of the Invention

[0004] The purpose of this invention is to provide a double-sided temperature-sensitive high-voltage PCB circuit board and its manufacturing method.

[0005] To achieve the above objectives, the technical solution proposed by this invention is as follows: A double-sided temperature-sensing high-voltage PCB circuit board, comprising: An organic insulating substrate having a first surface and a second surface disposed opposite to each other, and having at least one embedded cavity pre-formed therein that extends through its thickness.

[0006] At least one double-sided temperature-sensing ceramic sensing unit is fixedly embedded in the mounting cavity, and its thickness direction is consistent with the thickness direction of the organic insulating substrate.

[0007] The double-sided temperature-sensing ceramic sensing unit includes: a ceramic insulating body, which has an upper temperature-sensing surface and a lower temperature-sensing surface; At least one first temperature sensor is built into the ceramic insulating body in the region adjacent to the upper temperature sensing surface; At least one second temperature sensor is built into the area of ​​the ceramic insulating body adjacent to the lower temperature sensing surface; The first conductive interconnect structure electrically leads the first temperature sensor to the upper temperature sensing surface; The second conductive interconnect structure electrically leads the second temperature sensor to the lower sensing surface; A first metal circuit layer is disposed on the first surface of the organic insulating substrate and electrically connected to the first conductive interconnect structure; A second metal circuit layer is disposed on the second surface of the organic insulating substrate and electrically connected to the second conductive interconnect structure; The material of the organic insulating substrate has a greater coefficient of thermal expansion than that of the ceramic insulating body, and the inner wall of the embedding cavity and the outer peripheral surface of the double-sided temperature-sensing ceramic sensing unit are filled and solidified by potting material.

[0008] The inner wall of the mounting cavity is provided with a concave-convex interlocking structure, and the potting material is filled in the concave-convex interlocking structure to enhance the mechanical bonding force and thermal stress resistance between the organic insulating substrate and the double-sided temperature-sensing ceramic sensing unit.

[0009] The upper and / or lower sensing surfaces of the double-sided temperature-sensing ceramic sensing unit are coplanar with or slightly protrude from the corresponding surfaces of the organic insulating substrate, along with the mounting areas of the power-carrying chips in the first and / or second metal circuit layers.

[0010] The ceramic insulating body is made of dense ceramic material in the areas between the upper temperature sensing surface and the first temperature sensor, and between the lower temperature sensing surface and the second temperature sensor. The thickness of the ceramic insulating body is less than or equal to 0.5 mm, and the thermal conductivity is greater than 15 W / (m·K).

[0011] The first conductive interconnect structure and / or the second conductive interconnect structure include: A conductor formed inside a ceramic insulating body; and vertical interconnecting holes that electrically guide the conductor to the upper and lower temperature-sensing surfaces, respectively.

[0012] A method for manufacturing a double-sided temperature-sensing high-voltage PCB circuit board includes the following steps: S1. Fabrication of a double-sided temperature-sensing ceramic sensing unit: A ceramic insulating layer is provided, and a first temperature sensor and a second temperature sensor are pre-embedded inside it. A first and second conductive interconnection structure is formed to lead the electrical properties of the two sensors to the upper and lower surfaces of the ceramic insulating layer, respectively, to obtain an independent double-sided temperature-sensing ceramic sensing unit.

[0013] S2. Processing organic core board: Provide a copper-clad organic core board and process it at a predetermined position to form a through-hole embedding cavity.

[0014] S3. Unit embedding and fixing: The double-sided temperature-sensing ceramic sensing unit is placed into the embedding cavity, and the gap is filled with potting material. After curing, the double-sided temperature-sensing ceramic sensing unit and the organic core board are fixed together to form a composite core board.

[0015] S4. Lamination and Circuit Patterning: Prepreg and outer copper foil are laminated on the upper and lower surfaces of the composite core board to make the upper and lower surfaces of the double-sided temperature-sensing ceramic sensing unit in close contact with the corresponding outer copper foil; then, the outer copper foil is patterned and etched to form a first metal circuit layer and a second metal circuit layer that are electrically connected to the first conductive interconnect structure and the second conductive interconnect structure, respectively.

[0016] In step S2, when processing the embedded cavity, a concave-convex interlocking structure is formed on its inner wall using laser ablation or precision milling.

[0017] In step S3, the potting material is an epoxy resin or polyimide composite material filled with ceramic powder or boron nitride powder, and its coefficient of thermal expansion after curing is between that of the organic core board and the double-sided temperature-sensing ceramic sensing unit.

[0018] The specific steps for fabricating the double-sided temperature-sensing ceramic sensing unit in step S1 include: S11, Provide the first ceramic green belt.

[0019] S12. A first temperature sensor and its first lead conductor are installed on the first ceramic green belt by printing or mounting.

[0020] S13. A second ceramic green belt is stacked, and a second temperature sensor and its second lead conductor are set on the surface of the second ceramic green belt away from the first ceramic green belt by printing or mounting.

[0021] S14. A third ceramic green belt is superimposed on and covered the outer surface of the first ceramic green belt and the second ceramic.

[0022] S15. Corresponding to the first temperature sensor and the second temperature sensor, through holes are opened on the third ceramic green belt, and conductive paste is filled into the through holes to form a vertical interconnection structure.

[0023] S16. Co-pressing and co-firing are performed to form a sintered ceramic matrix with an embedded sensor.

[0024] S17. Metallize the upper and lower surfaces of the ceramic substrate to form upper surface pads and lower surface pads that are respectively connected to the first lead conductor and the second lead conductor, thereby completing the fabrication of the double-sided temperature-sensing ceramic sensing unit.

[0025] In step S17, metallization is achieved using magnetron sputtering, electroplating, or low-temperature sintering of conductive paste.

[0026] The beneficial effects of this invention are: By embedding prefabricated double-sided temperature-sensing ceramic sensing units into an organic insulating substrate, the heat transfer path is effectively shortened and the thermal resistance of the organic adhesive layer is eliminated. This enables accurate detection of the junction temperature of double-sided power devices on a PCB circuit board. The thermal expansion coefficient of the potting material is between that of the organic insulating substrate and the double-sided temperature-sensing ceramic sensing unit, forming a stress buffer layer that works in conjunction with the mechanical interlocking structure to resist the thermomechanical stress generated by power cycling. This ensures the operational stability of the PCB circuit board under harsh operating conditions and successfully resolves the core contradiction between high-voltage insulation and reliable integration of heterogeneous materials. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the overall structure of Embodiment 1 of the present invention; Figure 2 This is a cross-sectional view of the double-sided temperature-sensing ceramic sensing unit according to Embodiment 1 of the present invention; Figure 3 This is a cross-sectional view of the overall structure of Embodiment 2 of the present invention; Figure 4 This is a flowchart of the manufacturing method according to Embodiment 3 of the present invention.

[0028] In the figure: 1. Organic insulating substrate; 2. Ceramic insulating body; 3. First temperature sensor; 4. Second temperature sensor; 5. First conductive interconnect structure; 6. Second conductive interconnect structure; 7. First metal circuit layer; 8. Second metal circuit layer; 9. Encapsulating material. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings. Example 1: A double-sided temperature-sensing high-voltage PCB circuit board, comprising: An organic insulating substrate 1 has a first surface and a second surface disposed opposite to each other, and at least one embedded cavity extending through its thickness is pre-formed inside.

[0030] At least one double-sided temperature-sensing ceramic sensing unit is fixedly embedded in the mounting cavity, and its thickness direction is consistent with the thickness direction of the organic insulating substrate 1.

[0031] The double-sided temperature-sensing ceramic sensing unit includes: a ceramic insulating body 2, which has an upper temperature-sensing surface and a lower temperature-sensing surface; At least one first temperature sensor 3 is built into the area adjacent to the upper temperature sensing surface of the ceramic insulating body 2; At least one second temperature sensor 4 is built into the area adjacent to the lower temperature sensing surface of the ceramic insulating body 2; The first conductive interconnection structure 5 electrically leads the first temperature sensor 3 to the upper temperature sensing surface; The second conductive interconnect structure 6 electrically leads the second temperature sensor 4 to the lower temperature sensing surface; The first metal circuit layer 7 is disposed on the first surface of the organic insulating substrate 1 and is electrically connected to the first conductive interconnect structure 5. The second metal circuit layer 8 is disposed on the second surface of the organic insulating substrate 1 and is electrically connected to the second conductive interconnect structure 6. In this embodiment, the coefficient of thermal expansion of the organic insulating substrate 1 is greater than that of the ceramic insulating body 2, and the inner wall of the embedding cavity and the outer peripheral surface of the double-sided temperature-sensing ceramic sensing unit are filled and solidified by potting material 9. The overall structural cross-sectional view of the first embodiment of the present invention is shown below. Figure 1 As shown.

[0032] The ceramic insulating body 2 has a dense ceramic material in the areas between the upper temperature sensing surface and the first temperature sensor 3, and between the lower temperature sensing surface and the second temperature sensor 4. The thickness of this material is less than or equal to 0.5 mm, and its thermal conductivity is greater than 15 W / (m·K). A cross-sectional view of the double-sided temperature-sensing ceramic sensing unit in Embodiment 1 of the present invention is shown below. Figure 2 As shown.

[0033] The first conductive interconnect structure 5 and / or the second conductive interconnect structure 6 include: A conductor formed inside the ceramic insulating body 2; and vertical interconnecting holes that electrically guide the conductor to the upper and lower temperature sensing surfaces, respectively.

[0034] Example 2: Based on Embodiment 1, the inner wall of the embedding cavity is provided with a concave-convex interlocking structure, and the potting material 9 is filled in the concave-convex interlocking structure to enhance the mechanical bonding force and thermal stress resistance between the organic insulating substrate 1 and the double-sided temperature-sensing ceramic sensing unit. The overall structural cross-sectional view of Embodiment 2 of the present invention is shown below. Figure 3 As shown.

[0035] The upper and / or lower sensing surfaces of the double-sided temperature-sensing ceramic sensing unit are coplanar with or slightly protrude from the corresponding surfaces of the power-carrying chip mounting areas of the first metal circuit layer 7 and / or the second metal circuit layer 8.

[0036] Example 3: A method for manufacturing a double-sided temperature-sensing high-voltage PCB circuit board includes the following steps: S1. Fabrication of a double-sided temperature-sensing ceramic sensing unit: A ceramic insulating layer is provided, and a first temperature sensor 3 and a second temperature sensor 4 are pre-embedded inside it. A first and second conductive interconnection structure 6 is formed to lead the electrical properties of the two sensors to the upper and lower surfaces of the ceramic insulating layer, respectively, to obtain an independent double-sided temperature-sensing ceramic sensing unit.

[0037] S2. Processing organic core board: Provide a copper-clad organic core board and process it at a predetermined position to form a through-hole embedding cavity.

[0038] S3. Unit mounting and fixing: The double-sided temperature-sensing ceramic sensing unit is placed into the mounting cavity, and the gap is filled with potting material 9. After curing, the double-sided temperature-sensing ceramic sensing unit and the organic core board are fixed together to form a composite core board.

[0039] S4. Lamination and Circuit Patterning: A prepreg and an outer copper foil are laminated onto the upper and lower surfaces of the composite core board to ensure close contact between the upper and lower surfaces of the double-sided temperature-sensing ceramic sensing unit and the corresponding outer copper foil. Subsequently, the outer copper foil is patterned and etched to form a first metal circuit layer 7 and a second metal circuit layer 8, which are electrically connected to the first conductive interconnect structure 5 and the second conductive interconnect structure 6, respectively. The manufacturing method flowchart of Embodiment 3 of this invention is shown below. Figure 4 As shown.

[0040] In step S2, when processing the embedded cavity, a concave-convex interlocking structure is formed on its inner wall using laser ablation or precision milling.

[0041] In step S3, the potting material 9 is an epoxy resin or polyimide composite material filled with ceramic powder or boron nitride powder, and its coefficient of thermal expansion after curing is between that of the organic core board and the double-sided temperature-sensing ceramic sensing unit.

[0042] The specific steps for fabricating the double-sided temperature-sensing ceramic sensing unit in step S1 include: S11, Provide the first ceramic green belt.

[0043] S12. The first temperature sensor 3 and its first lead conductor are set on the first ceramic green belt by printing or mounting.

[0044] S13. Overlay a second ceramic green belt, and place a second temperature sensor 4 and its second lead conductor on the surface of the second ceramic green belt away from the first ceramic green belt by printing or mounting.

[0045] S14. A third ceramic green belt is superimposed on and covered the outer surface of the first ceramic green belt and the second ceramic.

[0046] S15. Corresponding to the first temperature sensor 3 and the second temperature sensor 4, through holes are opened on the third ceramic green belt, and conductive paste is filled into the through holes to form a vertical interconnection structure.

[0047] S16. Co-pressing and co-firing are performed to form a sintered ceramic matrix with an embedded sensor.

[0048] S17. Metallize the upper and lower surfaces of the ceramic substrate to form upper surface pads and lower surface pads that are respectively connected to the first lead conductor and the second lead conductor, thus completing the fabrication of the double-sided temperature-sensing ceramic sensing unit.

[0049] In step S17, metallization is achieved using magnetron sputtering, electroplating, or low-temperature sintering of conductive paste.

[0050] Example 4: A double-sided temperature-sensing high-voltage PCB circuit board for use in a servo driver power unit includes an FR-4 type organic insulating substrate 1. At a specific position in the middle of the substrate, directly below the subsequent power MOSFET mounting area, a rectangular mounting cavity is pre-formed. A separately fabricated double-sided temperature-sensing ceramic sensing unit is fixedly mounted in the mounting cavity.

[0051] The double-sided temperature-sensing ceramic sensing unit consists of an aluminum nitride ceramic insulating body 2 with dimensions of 10mm×10mm×0.8mm. The upper and lower temperature-sensing surfaces are coplanar with the upper and lower surfaces of the PCB circuit board, respectively. Within the ceramic insulating body 2, a thin-film platinum resistance thermometer is embedded 0.3mm away from the upper temperature-sensing surface as a first temperature sensor 3. Another identical thin-film platinum resistance thermometer is symmetrically embedded 0.3mm away from the lower temperature-sensing surface as a second temperature sensor 4. The function of the 0.3mm thin layer of high thermal conductivity aluminum nitride is to ensure that heat can be transferred to the sensor with minimal delay and attenuation, thereby achieving rapid and accurate sensing of the junction temperature of power devices attached to the upper and lower surfaces of the PCB circuit board.

[0052] Each platinum resistance thermometer is connected to a vertical interconnection hole on the surface of the ceramic insulating body 2 via a silver paste conductor printed on the ceramic green body. The vertical interconnection hole is filled with copper paste and sintered. Finally, copper-nickel-gold surface-treated pads are formed on the upper and lower sensing surfaces to serve as the first and second conductive interconnection structures 6, which can realize highly reliable electrical output of sensor signals from the inside of the ceramic to the outside.

[0053] There is a gap of about 0.1 mm between the inner wall of the mounting cavity and the outer peripheral surface of the double-sided temperature-sensing ceramic sensing unit. The cavity is filled with epoxy resin potting material 9 filled with boron nitride powder. The potting material 9 can fix and protect the double-sided temperature-sensing ceramic sensing unit. Its coefficient of thermal expansion is between FR-4 and aluminum nitride, which can buffer the stress caused by the difference in thermal expansion between the two and prevent cracking or delamination between them.

[0054] On the upper and lower surfaces of the organic insulating substrate 1, a first metal circuit layer 7 and a second metal circuit layer 8 are fabricated. They are interconnected through through-holes. Some of the wires on the first metal circuit layer 7 are connected to the upper surface pads of the double-sided temperature-sensing ceramic sensing unit by soldering. Similarly, the wires on the second metal circuit layer 8 are connected to the lower surface pads, which can seamlessly connect the sensing signal to the main control circuit network of the PCB.

[0055] A method for manufacturing a double-sided temperature-sensing high-voltage PCB circuit board for use in a servo driver power unit includes the following steps: Step S1: Fabrication of the ceramic sensing unit: Using low-temperature co-fired ceramic technology, firstly, three layers of aluminum nitride green ceramic tape are prepared. Silver paste is printed on the first green ceramic tape to form the electrode pattern of the first platinum resistor and a chip is mounted thereon. Then, a second green ceramic tape with through holes is stacked on top, and the through holes are filled with silver paste. The electrodes of the second platinum resistor are printed on the surface of the second green ceramic tape and a chip is mounted thereon. Finally, a third green ceramic tape is covered on the surfaces of the first and second green ceramic tapes. After isostatic pressing, the stacked layers are co-fired at 850°C in a nitrogen atmosphere to form an integrated ceramic substrate. Subsequently, pads are formed on the upper and lower surfaces by magnetron sputtering and pattern electroplating to complete the unit fabrication.

[0056] Step S2, Processing the organic core board: Take a 1.0mm thick, double-sided copper-clad FR-4 core board and use a carbon dioxide laser to ablate at the set position to form a 10.2mm×10.2mm through rectangular window, i.e., the mounting cavity.

[0057] Step S3, Unit Installation and Fixing: The ceramic sensing unit is precisely placed inside the window, and the aforementioned boron nitride / epoxy resin potting compound is injected into the surrounding gaps using a dispensing machine. It is then cured at 80°C for 2 hours to form a firmly bonded composite core board.

[0058] Step S4, Lamination and Patterning: A prepreg and an 18μm thick copper foil are stacked on the top and bottom sides of the composite core board. The board is then placed in a vacuum press and pressed at 180℃ and 3MPa for 90 minutes. The prepreg melts and flows, wrapping around the edges of the ceramic unit and bonding with the upper and lower copper foils. After pressing, standard photolithography, development, and etching processes are used to form the required circuit patterns on the upper and lower outer copper foils. It is ensured that the circuit achieves good electrical connection with the pads on the upper and lower surfaces of the ceramic unit. Contact can be achieved through heat and pressure during pressing or by supplementing with microporous electroplating.

[0059] Example 5: Based on Example 4, the circuit board structure is adjusted for high-power, high-vibration application environments by adding a concave-convex interlocking structure. A continuous dovetail groove is precision milled into the inner wall of the embedding cavity of the FR-4 organic insulating substrate 1. After the corresponding potting material 9 is cured, it forms a protrusion that interlocks with it. The concave-convex interlocking structure can increase the bonding area and shear resistance between the ceramic unit and the organic substrate. Especially in frequent power cycles, i.e., under the conditions of thermal stress and vehicle vibration, it can effectively prevent relative displacement or delamination between the two, significantly improving long-term reliability.

[0060] Its surface features a raised design, with the thickness of the double-sided temperature-sensing ceramic sensing unit slightly greater than that of the core board. This causes the upper and lower temperature-sensing surfaces to protrude slightly from the surfaces of the first and second metal circuit layers 8 of the PCB board by about 0.05mm after lamination. This structure allows the raised ceramic surface to make closer contact with the module base plate when the power IGBT module is mounted on the PCB board surface with thermal grease, and even to produce slight deformation to fill microscopic gaps, further reducing contact thermal resistance and optimizing temperature response speed. At the same time, the metal pads on the ceramic surface can still be reliably connected to the circuit layers of the PCB board through conductive glue or soldering.

[0061] When the above structure is adopted, a precision CNC milling machine is used in step S2 to mill the embedded cavity on the FR-4 core plate with a carbide end mill, and dovetail grooves are machined on the side wall at the same time.

[0062] In step S3, the dimensional tolerance of the ceramic unit is more strictly controlled, and it is ensured that after it is placed, the upper and lower surfaces are slightly higher than the core plate.

[0063] In step S4, due to the micro-protrusion of the ceramic unit, the prepreg and copper foil will undergo local deformation during the pressing process to adapt to this protrusion, and after pressing, the ceramic unit and the PCB circuit board surface form a smooth transition.

[0064] Example 6: Based on Example 1, polyimide copper-clad laminate can be used instead of FR-4, as polyimide has a higher glass transition temperature and a lower coefficient of thermal expansion.

[0065] Using polyimide composite material with alumina ceramic powder as filler as potting compound, its coefficient of thermal expansion after curing can be adjusted to about 20 ppm / °C.

[0066] The pads on the upper and lower surfaces of the ceramic unit are made of low-temperature sintered silver paste.

[0067] Because the gradient of thermal expansion coefficients among the polyimide substrate, the potting compound of the ceramic filler, and the ceramic unit is better and the matching is better, the thermal stress is less in a wide temperature range of -55℃ to 200℃, the low-temperature sintering silver paste is more compatible with the process temperature of polyimide, and the conductivity and reliability meet the requirements, the circuit board made using this embodiment is suitable for working environments with higher operating temperatures and higher dimensional stability.

[0068] When using the above materials, in step S1, high-temperature co-fired ceramic technology is used to sinter the silicon nitride ceramic substrate at 1600℃ in a reducing atmosphere. The sensor is a high-temperature resistant tungsten resistor. After sintering, low-temperature sintered silver paste is screen-printed and rapidly heat-treated to form pads on the upper and lower surfaces.

[0069] In step S3, the dispensing and curing of the potting compound must be carried out under nitrogen protection, and the curing temperature must be matched with the pre-curing process of the polyimide.

[0070] In step S4, since the polyimide prepreg requires higher lamination temperature and pressure (greater than 300°C), the lamination parameters were adjusted.

[0071] Working principle: A high thermal conductivity ceramic unit with an integrated temperature sensor is embedded in the PCB circuit board, ensuring a short distance between the sensor and the upper and lower surfaces of the ceramic unit. This shortens the heat transfer path and eliminates the significant thermal resistance of the organic adhesive layer, enabling the sensor to capture transient changes in the chip junction temperature in real time. This lays the physical foundation for precise thermal management. A combination of prefabricated ceramic sensing units, gradient potting, and mechanical interlocking eliminates performance drift caused by organic adhesive aging and prevents cracking or delamination between the ceramic unit and the PCB substrate. The sensor is embedded in a ceramic medium with electromagnetic shielding effect, improving the signal-to-noise ratio of the sensor output signal to enhance the accuracy of the control system's judgment of the thermal state. The use of prefabricated double-sided temperature-sensing ceramic units eliminates the need to change the substrate material and does not occupy effective wiring area, achieving the goal of adding high-end monitoring functions to ordinary PCB circuit boards. The overall cost is controllable and easy to mass-produce. The composite insulation system composed of local ceramic reinforcement and the overall organic substrate balances the reliability of high-voltage insulation with the process feasibility of system integration.

[0072] The beneficial effects of this invention are that by embedding the prefabricated double-sided temperature-sensing ceramic sensing unit in the organic insulating substrate, the heat transfer path is effectively shortened and the thermal resistance of the organic adhesive layer is eliminated. This enables accurate detection of the junction temperature of double-sided power devices on the PCB circuit board. The thermal expansion coefficient of the potting material is between that of the organic insulating substrate and the double-sided temperature-sensing ceramic sensing unit, forming a stress buffer layer to work in conjunction with the mechanical interlocking structure to resist the thermomechanical stress generated by power cycling. This ensures the working stability of the PCB circuit board under harsh operating conditions and successfully solves the core contradiction between high-voltage insulation and reliable integration of heterogeneous materials.

[0073] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A double-sided temperature-sensing high-voltage PCB circuit board, characterized in that, include: An organic insulating substrate (1) has a first surface and a second surface disposed opposite to each other, and has at least one embedded cavity that extends through its thickness. At least one double-sided temperature-sensing ceramic sensing unit is fixedly embedded in the mounting cavity, and its thickness direction is consistent with the thickness direction of the organic insulating substrate (1). The double-sided temperature-sensing ceramic sensing unit includes: The ceramic insulating body (2) has an upper temperature sensing surface and a lower temperature sensing surface; At least one first temperature sensor (3) is built into the area of ​​the ceramic insulating body (2) adjacent to the upper temperature sensing surface; At least one second temperature sensor (4) is built into the area of ​​the ceramic insulating body (2) adjacent to the lower temperature sensing surface; The first conductive interconnect structure (5) electrically leads the first temperature sensor (3) to the upper temperature sensing surface; The second conductive interconnect structure (6) electrically leads the second temperature sensor (4) to the lower temperature sensing surface; A first metal circuit layer (7) is disposed on the first surface of the organic insulating substrate (1) and electrically connected to the first conductive interconnect structure (5); The second metal circuit layer (8) is disposed on the second surface of the organic insulating substrate (1) and is electrically connected to the second conductive interconnect structure (6); The material thermal expansion coefficient of the organic insulating substrate (1) is greater than that of the ceramic insulating body (2), and the inner wall of the embedding cavity and the outer peripheral surface of the double-sided temperature-sensing ceramic sensing unit are filled and solidified by potting material (9).

2. The double-sided temperature-sensing high-voltage PCB circuit board as described in claim 1, characterized in that, The inner wall of the mounting cavity is provided with a concave-convex interlocking structure, and the potting material (9) is filled in the concave-convex interlocking structure to enhance the mechanical bonding force and thermal stress resistance between the organic insulating substrate (1) and the double-sided temperature-sensing ceramic sensing unit.

3. A double-sided temperature-sensing high-voltage PCB circuit board as described in claim 1 or 2, characterized in that, The upper and / or lower sensing surfaces of the double-sided temperature-sensing ceramic sensing unit are coplanar with or slightly protrude from the corresponding surfaces of the organic insulating substrate (1) of the mounting area of ​​the power-carrying chip of the first metal circuit layer (7) and / or the second metal circuit layer (8).

4. A double-sided temperature-sensing high-voltage PCB circuit board as described in claim 1, characterized in that, The ceramic insulating body (2) is made of dense ceramic material in the area between the upper temperature sensing surface and the first temperature sensor (3) and between the lower temperature sensing surface and the second temperature sensor (4), with a thickness of less than or equal to 0.5 mm and a thermal conductivity greater than 15 W / (m·K).

5. A double-sided temperature-sensing high-voltage PCB circuit board as described in claim 1, characterized in that, The first conductive interconnect structure (5) and / or the second conductive interconnect structure (6) include: Conductors formed inside the ceramic insulating body (2); In addition, vertical interconnecting holes electrically guide the conductors to the upper and lower sensing surfaces, respectively.

6. A method for manufacturing a double-sided temperature-sensing high-voltage PCB circuit board as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of double-sided temperature-sensing ceramic sensing unit: Provide a ceramic insulating layer, embed a first temperature sensor (3) and a second temperature sensor (4) inside it, and form a first and second conductive interconnection structure (6) that leads the electrical properties of the two to the upper and lower surfaces of the ceramic insulating layer respectively, to obtain an independent double-sided temperature-sensing ceramic sensing unit. S2. Processing organic core board: Provide a copper-clad organic core board and process it to form a through-hole embedding cavity at a predetermined position; S3, Unit embedding and fixing: The double-sided temperature-sensing ceramic sensing unit is placed into the embedding cavity, and the gap is filled with potting material (9). After curing, the double-sided temperature-sensing ceramic sensing unit and the organic core board are fixed together to form a composite core board. S4. Lamination and Circuit Patterning: Prepreg and outer copper foil are laminated on the upper and lower surfaces of the composite core board to make the upper and lower surfaces of the double-sided temperature-sensing ceramic sensing unit in close contact with the corresponding outer copper foil. Subsequently, the outer copper foil is patterned and etched to form a first metal circuit layer (7) and a second metal circuit layer (8) that are electrically connected to the first conductive interconnect structure (5) and the second conductive interconnect structure (6), respectively.

7. The manufacturing method of a double-sided temperature-sensing high-voltage PCB circuit board as described in claim 6, characterized in that, In step S2, when processing the embedded cavity, a concave-convex interlocking structure is formed on its inner wall using laser ablation or precision milling.

8. The manufacturing method of a double-sided temperature-sensing high-voltage PCB circuit board as described in claim 6, characterized in that, In step S3, the potting material (9) is an epoxy resin or polyimide composite material filled with ceramic powder or boron nitride powder, and its coefficient of thermal expansion after curing is between that of the organic core board and the double-sided temperature-sensing ceramic sensing unit.

9. The manufacturing method of a double-sided temperature-sensing high-voltage PCB circuit board as described in claim 6, characterized in that, The specific steps for fabricating the double-sided temperature-sensing ceramic sensing unit in step S1 include: S11, Provide the first ceramic green body belt; S12. A first temperature sensor (3) and its first lead conductor are set on the first ceramic green belt by printing or mounting. S13. Overlay a second ceramic green belt, and install a second temperature sensor (4) and its second lead conductor on the surface of the second ceramic green belt away from the first ceramic green belt by printing or mounting. S14. A third ceramic green belt is superimposed on and covered the outer surface of the first ceramic green belt and the second ceramic; S15. Corresponding to the first temperature sensor (3) and the second temperature sensor (4), through holes are opened on the third ceramic green belt, and conductive paste is filled in the through holes to form a vertical interconnection structure. S16. Perform co-pressing and co-firing to form a sintered ceramic matrix with embedded sensors. S17. Metallize the upper and lower surfaces of the ceramic substrate to form upper surface pads and lower surface pads that are respectively connected to the first lead conductor and the second lead conductor, thereby completing the fabrication of the double-sided temperature-sensing ceramic sensing unit.

10. A method for manufacturing a double-sided temperature-sensing high-voltage PCB circuit board as described in claim 9, characterized in that, In step S17, metallization is achieved using magnetron sputtering, electroplating, or low-temperature sintering of conductive paste.

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