Two-in-one power semiconductor device

Abstract

The invention provides a two-in-one power semiconductor device, and relates to the technical field of semiconductor devices, the two-in-one power semiconductor device comprises a substrate, a wafer, a plastic package body, a plurality of power pins, a plurality of signal pins and a heat dissipation plate, the wafer is arranged on the upper surface of the substrate, the power pins and the signal pins are electrically connected with the substrate and the wafer, the plastic package body packages the substrate and the wafer, and the heat dissipation plate is arranged on the substrate. The heat dissipation plate is arranged on the lower surface of the substrate, a cavity is formed in the heat dissipation plate, and the cavity is filled with a heat-conducting medium. According to the invention, after local heat generated by working of the wafer is transferred to the top wall of the cavity of the heat dissipation plate through the substrate, the local heat can be quickly conducted to the heat-conducting medium, and the heat-conducting medium forms natural convection due to regional temperature difference, so that the heat is uniformly diffused in the whole region of the heat dissipation plate, and the heat is prevented from being accumulated right below the heating region of the wafer to form local hot spots; the wafer aging speed is delayed, the overall service life of the device is prolonged, the working stability of the device under the working condition of high power density is improved, and the integrated application requirement of a vehicle-mounted thermal management system is met.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a two-in-one power semiconductor device. Background Technology

[0002] As new energy vehicles develop towards longer driving range and faster charging, the demand for integrated and miniaturized power semiconductor devices in vehicle thermal management systems is becoming increasingly urgent. E-Comp (electronic compressor controller) and PTC (positive temperature coefficient heater) are core components of vehicle thermal management. The traditional separate layout of E-Comp and PTC has problems such as large space occupation, high wiring harness loss, and slow response of coordinated control. Therefore, the industry is gradually turning to the development of E-Comp and PTC combined power semiconductor devices.

[0003] Existing E-Comp and PTC dual-mode power semiconductor devices, by integrating E-Comp and PTC, significantly improve the power density of semiconductor devices. The core power wafer of these devices generates a large amount of heat during operation, and this heat is often concentrated in localized high-power areas of the wafer. Therefore, heat dissipation performance directly determines the device's operational stability and lifespan. Currently, the heat dissipation function of dual-mode power semiconductor devices mainly relies on the substrate itself or a metal heat sink (such as an aluminum alloy or copper-based heat sink) attached to the lower surface of the substrate. This heat dissipation relies on the excellent thermal conductivity of the metal material to conduct the heat generated by the wafer to the entire heat sink, and then dissipate it to external heat dissipation terminals.

[0004] However, the thermal conductivity of traditional metal heat sinks is easily limited by factors such as material uniformity and internal microstructural defects (e.g., pores, cracks, and loose grain boundaries). Alloy heat sinks, in particular, are prone to compositional segregation during melt solidification, leading to uneven distribution of alloy elements across different areas, with some areas exhibiting higher or lower concentrations. Due to the inherent differences in thermal conductivity between metal substrates composed of different materials, the overall thermal conductivity of the heat sink becomes uneven. When localized heating occurs on the wafer, heat preferentially transfers along the direction of higher metal thermal conductivity, making it difficult to diffuse quickly across the entire heat sink. This results in heat accumulating directly beneath the heated area, forming significant localized hotspots. The persistent presence of these hotspots causes local device temperatures to far exceed design thresholds. This accelerates the aging of semiconductor materials within the wafer, reducing power conversion efficiency and shortening device lifespan. Furthermore, excessive localized temperature differences can cause uneven thermal stress between the heat sink and the substrate, potentially leading to delamination at the bonding surface, further deteriorating heat dissipation performance, and in severe cases, even causing short-circuit failure. Summary of the Invention

[0005] This invention provides a two-in-one power semiconductor device to solve the technical problem that when localized heating occurs on the wafer of current semiconductor devices, heat continuously accumulates directly below the heating area of ​​the wafer, forming obvious local hot spots.

[0006] To address the aforementioned technical problems, this invention discloses a two-in-one power semiconductor device, comprising: a substrate, a wafer, a molding compound, multiple power pins, multiple signal pins, and a heat sink. The wafer is disposed on the upper surface of the substrate, and the power pins and signal pins are electrically connected to the substrate and the wafer. The molding compound encapsulates the substrate and the wafer, and the heat sink is disposed on the lower surface of the substrate. A cavity is formed inside the heat sink, and the cavity is filled with a thermally conductive medium.

[0007] Preferably, the output directions of multiple power pins are distributed on the first side of the substrate or the first side and the second side, and the output directions of multiple signal pins are distributed on the second side of the substrate, with the first side and the second side being arranged opposite to each other.

[0008] Preferably, both the power pins and signal pins adopt a right-angle bend structure.

[0009] Preferably, the molding compound encapsulates the periphery of the substrate and the outer side of the wafer.

[0010] Preferably, a temperature sensor is disposed on the substrate, and the temperature sensor is electrically connected to at least two signal pins. The temperature sensor is a negative temperature coefficient thermistor.

[0011] Preferably, an oil inlet is provided on the side wall of the heat sink, the oil inlet is connected to the cavity, the inner wall of the oil inlet is provided with internal threads, a sealing bolt is provided inside the oil inlet, the outer wall of the sealing bolt is provided with external threads that are compatible with the internal threads, and the sealing bolt and the inner wall of the oil inlet are sealed and connected by thread engagement.

[0012] Preferably, a plurality of support strips are provided inside the cavity, which divide the cavity into multiple heat-conducting cavities. The support strips are evenly distributed along the width direction of the substrate. The upper surface of the support strips is connected to the top wall of the cavity, and the lower surface of the support strips is connected to the bottom wall of the cavity. A plurality of connecting holes are provided through the bottom of the support strips. The connecting holes are evenly distributed along the length direction of the support strips, and the two ends of the connecting holes are respectively connected to the heat-conducting cavities adjacent to both sides of the support strips.

[0013] Preferably, a heat-conducting component is provided inside the heat-conducting cavity. The heat-conducting component includes a heat-conducting seat and a connecting cylinder. The upper end of the heat-conducting seat is connected to the top wall of the heat-conducting cavity. The heat-conducting seat is funnel-shaped. A connecting cylinder is provided at the lower end of the heat-conducting seat. The upper end of the connecting cylinder is connected to the interior of the heat-conducting seat. A first limiting ring is provided inside the connecting cylinder. The outer wall of the first limiting ring is fixedly connected to the inner wall of the connecting cylinder. A push plate is provided below the first limiting ring. The outer wall of the push plate is slidably connected to the inner wall of the connecting cylinder. The space above the push plate and the interior space of the heat-conducting seat form a storage cavity. The storage cavity stores the heat-conducting medium. The push plate is connected to the top wall of the storage cavity through a first spring. A fixing plate is provided below the push plate. The outer wall of the fixing plate is fixedly connected to the inner wall of the connecting cylinder. Several first through holes are evenly opened along the circumference of the side wall of the connecting cylinder. The first through holes are located between the fixing plate and the first limiting ring. An inlet pipe is provided at the center of the push plate. The upper end of the inlet pipe is connected to the storage cavity. The lower end of the inlet pipe passes through the fixing plate and is connected to the lower part of the fixing plate. A one-way valve is provided inside the inlet pipe.

[0014] Preferably, the lower end of the connecting cylinder is connected to the bottom wall of the heat-conducting cavity, and a number of liquid inlet holes are provided near the lower outer wall of the connecting cylinder, and the number of liquid inlet holes are distributed in a ring array about the central axis of the connecting cylinder.

[0015] Preferably, a sliding plate is provided below the fixed plate, and the outer wall of the sliding plate is slidably connected to the inner wall of the connecting cylinder. The upper surface of the sliding plate is connected to the lower surface of the fixed plate through a second spring. Second limiting rings are provided at intervals below the sliding plate, and the outer wall of the second limiting rings is fixedly connected to the inner wall of the connecting cylinder. Several second through holes are evenly opened along the circumference of the side wall of the connecting cylinder, and the second through holes are located between the fixed plate and the sliding plate.

[0016] The technical solution of this invention has the following advantages: This invention provides a two-in-one power semiconductor device, relating to the field of semiconductor device technology, including a substrate, a wafer, a molding compound, multiple power pins, multiple signal pins, and a heat sink. The wafer is disposed on the upper surface of the substrate, and the power pins and signal pins are electrically connected to the substrate and the wafer. The molding compound encapsulates the substrate and the wafer. The heat sink is disposed on the lower surface of the substrate, and a cavity is formed within the heat sink, filled with a thermally conductive medium. In this invention, by setting a cavity within the heat sink and filling the cavity with a thermally conductive medium, the local heat generated by the wafer during operation is transferred to the top wall of the cavity via the substrate and then quickly conducted to the thermally conductive medium. The thermally conductive medium forms natural convection due to the regional temperature difference, and combined with the cavity structure, achieves uniform heat diffusion throughout the entire heat sink, effectively preventing heat accumulation directly below the wafer's heating area and the formation of local hot spots. This design not only slows down the wafer aging rate and extends the overall lifespan of the device, but also improves the device's operational stability under high power density conditions, meeting the integrated application requirements of automotive thermal management systems.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the means particularly pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the internal structure of a dual-in-one power semiconductor device according to the present invention; Figure 2 This is a circuit diagram of a dual-in-one power semiconductor device according to the present invention; Figure 3 This is a schematic diagram of another internal structure of a dual-in-one power semiconductor device according to the present invention; Figure 4 This is another circuit diagram of a two-in-one power semiconductor device according to the present invention; Figure 5 This is a schematic diagram from one perspective of a dual-in-one power semiconductor device according to the present invention; Figure 6 This is a schematic diagram from another perspective of a dual-in-one power semiconductor device according to the present invention; Figure 7 This is a schematic diagram of the internal structure of the heat sink in this invention; Figure 8 For the present invention Figure 7 Enlarged view of the structure at point A in the middle; Figure 9 This is a schematic diagram of the heat-conducting component in this invention; Figure 10 This is a schematic diagram of the internal structure of the heat-conducting component in this invention; Figure 11 For the present invention Figure 10 Enlarged view of the structure at point B in the middle; Figure 12 For the present invention Figure 11 Enlarged view of the structure at point C.

[0020] In the diagram: 1. Substrate; 2. Wafer; 3. Molded enclosure; 4. Power pin; 5. Signal pin; 6. Heat sink; 7. Oil inlet; 8. Sealing bolt; 9. Support bar; 10. Heat-conducting cavity; 11. Connecting hole; 12. Heat-conducting base; 13. Connecting cylinder; 14. First limiting ring; 15. Push plate; 16. Storage cavity; 17. First spring; 18. Fixing plate; 19. First through hole; 20. Liquid inlet pipe; 21. Liquid inlet hole; 22. Sliding plate; 23. Second spring; 24. Second limiting ring; 25. Second through hole. Detailed Implementation

[0021] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0022] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] Example 1: This embodiment of the invention provides a two-in-one power semiconductor device, such as... Figures 1-12 As shown, it includes: a substrate 1, a wafer 2, a molding compound 3, multiple power pins 4, multiple signal pins 5, and a heat sink 6. The wafer 2 is disposed on the upper surface of the substrate 1. The power pins 4 and signal pins 5 are electrically connected to the substrate 1 and the wafer 2. The molding compound 3 encapsulates the substrate 1 and the wafer 2. The heat sink 6 is disposed on the lower surface of the substrate 1. A cavity is provided inside the heat sink 6, and the cavity is filled with a thermally conductive medium. The output directions of multiple power pins 4 are distributed on the first side of the substrate 1 or on the first side and the second side, and the output directions of multiple signal pins 5 are distributed on the second side of the substrate 1, with the first side and the second side being arranged opposite to each other. Both power pin 4 and signal pin 5 adopt a right-angle bent structure; The molding compound 3 encapsulates the periphery of the substrate 1 and the outer side of the wafer 2; A temperature sensor is disposed on the substrate 1. The temperature sensor is electrically connected to at least two signal pins 5. The temperature sensor is a negative temperature coefficient thermistor.

[0024] The working principle and beneficial effects of the above technical solution are as follows: The substrate 1 is a direct copper-clad substrate, and the wafer 2 is soldered onto the substrate 1. Adjacent wafers 2 can be isolated by insulating tape to avoid short circuits between wafers 2. The power pin 4 and signal pin 5 are stably electrically connected to the substrate 1 and wafer 2 through a right-angle bending structure. The power pin 4 is distributed on the first side or the first and second sides of the substrate 1, responsible for transmitting the current required for E-Comp and PTC operation, providing power for power conversion and heating functions. The signal pin 5 is concentrated on the second side of the substrate 1, transmitting control commands and status feedback signals of the device on one hand, and electrically connected to the temperature sensor on the substrate 1 on the other hand, collecting the device's operating temperature data in real time. The separate layout of the power pin 4 and signal pin 5 can avoid electromagnetic interference from the high current loop to the weak signal loop. Then, an epoxy resin encapsulation material is used to make a molding compound 3 on the substrate 1. The molding compound 3 wraps around the perimeter of the substrate 1, the outer side of the wafer 2, and the power pin 4 and signal pin. At the root of pin 5, a sealed protective structure is formed to isolate external dust, moisture, and corrosive media. At the same time, it fixes the relative positions of power pin 4, signal pin 5, substrate 1, and wafer 2, improving the mechanical stability of the device. A heat sink 6 is set on the lower surface of substrate 1. A cavity is set inside the heat sink 6 and filled with a thermally conductive medium, which is thermally conductive oil. The thermally conductive oil has fluidity. When the local heat generated by wafer 2 is transferred through substrate 1 to the top wall of the cavity of heat sink 6, it can be quickly conducted to the thermally conductive medium. Due to the temperature difference in the area, the thermally conductive medium forms natural convection. With the cavity structure, heat is evenly diffused throughout the heat sink 6, effectively preventing heat from accumulating directly below the heat-generating area of ​​wafer 2 and forming local hot spots (such as the high power density heat generation area after E-Comp and PTC integration). This design not only slows down the aging speed of wafer 2 and extends the overall service life of the device, but also improves the working stability of the device under high power density conditions, meeting the integrated application requirements of automotive thermal management systems. like Figures 1-4 The diagram shown is a schematic diagram of the internal structure and corresponding circuit diagram of a two-in-one power semiconductor device according to the present invention. Figure 1 It can be seen that power pins 4 include #1-#11 and #31, and signal pins 5 include #12-#30. Power pins 4 (#1-#11) are located on the first side of substrate 1, power pin 4 (#31) is located on the second side of substrate 1, and signal pins 5 (#12-#30) are all located on the second side of substrate 1. Figure 3As can be seen, power pins 4 include #1-#11, and signal pins 5 include #12-#31. Power pins 4, #1-#11, are located on the first side of substrate 1, while signal pins 5, #12-#31, are all located on the second side of substrate 1. Some wafers 2 on substrate 1 are connected by circuits to form an E-Comp drive branch, which is used to realize the power control of the electronic compressor. The remaining wafers 2 are arranged by circuit layout to form a PTC heating drive branch, which is used to output the working power required by the PTC heater, thereby realizing the integrated arrangement on substrate 1 and heat dissipation through heat sink 6 and the heat-conducting medium in heat sink 6.

[0025] Example 2: Based on Example 1 above, as follows Figure 1-6 As shown, an oil inlet 7 is provided on the side wall of the heat sink 6. The oil inlet 7 is connected to the cavity. The inner wall of the oil inlet 7 is provided with an internal thread. A sealing bolt 8 is provided inside the oil inlet 7. The outer wall of the sealing bolt 8 is provided with an external thread that matches the internal thread. The sealing bolt 8 and the inner wall of the oil inlet 7 are sealed and connected by thread engagement.

[0026] The working principle and beneficial effects of the above technical solution are as follows: Before assembling the device, first rotate and remove the sealing bolt 8, and inject a preset amount of heat-conducting medium into the cavity of the heat sink 6 through the oil injection port 7 to ensure that the heat-conducting medium completely fills the cavity, eliminating the thermal resistance risk caused by residual air. After filling, screw the sealing bolt 8 into the oil injection port 7, and achieve a tight fit through thread engagement to form a reliable sealing structure, preventing the heat-conducting medium from leaking during device operation. The thread engagement method of sealing can resist vibration under vehicle conditions and avoid the failure of heat dissipation function due to heat-conducting medium leakage.

[0027] Example 3: Based on Example 1 or 2, such as Figure 7 As shown, a plurality of support bars 9 are arranged inside the cavity, which divides the cavity into multiple heat-conducting cavities 10. The support bars 9 are evenly distributed along the width direction of the substrate 1. The upper surface of the support bars 9 is connected to the top wall of the cavity, and the lower surface of the support bars 9 is connected to the bottom wall of the cavity. A plurality of connecting holes 11 are provided through the bottom of the support bars 9. The connecting holes 11 are evenly distributed along the length direction of the support bars 9, and the two ends of the connecting holes 11 are respectively connected to the heat-conducting cavities 10 adjacent to both sides of the support bars 9.

[0028] The working principle and beneficial effects of the above technical solution are as follows: Multiple support bars 9 are set in the cavity, and the upper and lower surfaces of the support bars 9 are fixedly connected to the top and bottom walls of the cavity, respectively, thereby forming a longitudinal support structure. This offsets the decrease in mechanical strength of the heat sink 6 caused by the cavity structure and prevents the heat sink 6 from deforming or peeling off from the substrate 1 under vehicle vibration conditions. The support bars 9 divide the cavity into multiple heat conduction cavities 10. The heat generated by the wafer 2 is transferred to the top wall of the heat sink 6 through the substrate 1 and can be transferred to each heat conduction cavity 10 through the heat conduction medium. When the heat conduction medium forms natural convection due to regional temperature differences, the heat conduction cavity 10 can guide the convection direction and reduce heat transfer loss caused by turbulence. Furthermore, the heat conduction medium in each heat conduction cavity 10 can flow freely through the connecting holes 11 to achieve rapid heat exchange in different areas, avoid heat accumulation in a single heat conduction cavity 10, and further improve the heat uniformity of all areas in the heat sink 6.

[0029] Example 4: Based on Example 3, a heat-conducting assembly is provided inside the heat-conducting cavity 10. The heat-conducting assembly includes a heat-conducting seat 12 and a connecting cylinder 13. The upper end of the heat-conducting seat 12 is connected to the top wall of the heat-conducting cavity 10. The heat-conducting seat 12 is funnel-shaped. The lower end of the heat-conducting seat 12 is provided with the connecting cylinder 13. The upper end of the connecting cylinder 13 communicates with the interior of the heat-conducting seat 12. A first limiting ring 14 is provided inside the connecting cylinder 13. The outer wall of the first limiting ring 14 is fixedly connected to the inner wall of the connecting cylinder 13. A push plate 15 is provided below the first limiting ring 14. The outer wall of the push plate 15 is slidably connected to the inner wall of the connecting cylinder 13. The space above the push plate 15 of the connecting cylinder 13 is connected to the heat-conducting cavity. The interior space of the seat 12 forms a storage cavity 16, which stores a heat-conducting medium. The push plate 15 is connected to the top wall of the storage cavity 16 by a first spring 17. A fixing plate 18 is provided below the push plate 15. The outer wall of the fixing plate 18 is fixedly connected to the inner wall of the connecting cylinder 13. Several first through holes 19 are evenly opened along the circumference of the side wall of the connecting cylinder 13. The first through holes 19 are located between the fixing plate 18 and the first limiting ring 14. An inlet pipe 20 is provided at the center of the push plate 15. The upper end of the inlet pipe 20 is connected to the storage cavity 16, and the lower end of the inlet pipe 20 passes through the fixing plate 18 and is connected to the bottom of the fixing plate 18. A one-way valve is provided in the inlet pipe 20.

[0030] The working principle and beneficial effects of the above technical solution are as follows: Several heat-conducting components are also provided in the heat-conducting cavity 10. The heat-conducting components include heat-conducting seats 12. The upper end of the heat-conducting seat 12 is fixedly connected to the top wall of the heat-conducting cavity 10. The heat-conducting seat 12 corresponds one-to-one with the heat-generating area of ​​the wafer 2. The heat-conducting seat 12 is located directly below the corresponding heat-generating area. The heat-conducting seat 12 can be made of copper. Therefore, when the heat generated by the wafer 2 is transferred to the top wall of the heat-conducting cavity 10, the heat-conducting seat 12 can quickly receive the heat transferred by the wafer 2 because it is directly below the wafer 2. The lower end of the heat-conducting seat 12 is connected to a connecting cylinder 13. The space of the connecting cylinder 13 above the push plate 15 and the internal space of the heat-conducting seat 12 form a storage cavity 16. Initially, the storage cavity 16 is pre-filled with... The heat-conducting medium is the same heat-conducting oil as the heat-conducting medium in the heat-conducting cavity 10. The upper end of the first spring 17 is fixedly connected to the top wall of the storage cavity 16. The first spring 17 is in a naturally extended state. The upper surface of the push plate 15 is in contact with the lower surface of the first limiting ring 14. At this time, the storage cavity 16 cannot communicate with the first through hole 19. When the wafer 2 is locally heated, the heat generated by the wafer 2 is quickly transferred to the heat-conducting seat 12 through the substrate 1 and the top wall of the heat sink 6. The heat-conducting medium in the heat-conducting seat 12 expands due to heat. After the volume of the heat-conducting medium increases, it pushes the push plate 15 to slide downward. The first spring 17 is stretched. When the push plate 15 slides down to below the first through hole 19, the storage cavity 16 communicates with the first through hole 19. The heat-conducting medium in the storage cavity 16 is connected to the first through hole 19 through the first through hole 19. The heat-conducting medium ejected from the first through-hole 19 quickly reaches the outside of the connecting cylinder 13, carrying heat and forming directional convection within the heat-conducting cavity 10, rapidly transferring heat to the far end region of the heat-conducting cavity 10. When the wafer 2 experiences instantaneous concentrated heating, the heat-conducting medium in the storage cavity 16 can be quickly pushed outside the heating area, thereby accelerating the diffusion rate of local heat within the heat-conducting cavity 10, improving the thermal response speed, and preventing the formation of instantaneous local hot spots. The heat-conducting seat 12 is funnel-shaped, with the upper diameter of the heat-conducting seat 12 being larger than the lower diameter, thus expanding the heat receiving area and facilitating the rapid heating and expansion of the heat-conducting medium within the storage cavity 16. The fixing plate 18 can limit the downward movement distance of the push plate 15, preventing the first spring 17 from overshooting. When the thermal medium is sprayed out in a certain amount, the expansion pressure of the thermal medium in the storage cavity 16 gradually weakens, and the pushing force on the push plate 15 is less than the elastic force of the first spring 17. Under the action of the elastic force of the first spring 17, the push plate 15 slides upward, so that the first through hole 19 ends the connection with the storage cavity 16. When the wafer 2 cools down, the thermal medium in the storage cavity 16 shrinks and its volume decreases. Under the action of the elastic force of the first spring 17, the push plate 15 quickly resets and contacts the lower surface of the first limiting ring 14. As the thermal medium in the storage cavity 16 decreases, a negative pressure is generated in the storage cavity 16. The thermal medium in the thermal cavity 10 can flow into the storage cavity 16 through the liquid inlet pipe 20 to complete the automatic replenishment of the thermal medium, which is beneficial to the circulation of the thermal component.

[0031] Example 5: Based on Example 4, the lower end of the connecting cylinder 13 is connected to the bottom wall of the heat conduction cavity 10. Several liquid inlet holes 21 are provided near the lower outer wall of the connecting cylinder 13. The several liquid inlet holes 21 are distributed in a ring array about the central axis of the connecting cylinder 13.

[0032] The working principle and beneficial effects of the above technical solution are as follows: By fixing the lower end of the connecting cylinder 13 to the bottom wall of the heat conduction cavity 10, the supporting performance of the connecting cylinder 13 can be improved, further supporting the interior of the heat sink 6 and improving the mechanical strength of the heat sink 6. Several liquid inlet holes 21 are provided on the outer wall of the connecting cylinder 13. When the high-temperature heat conduction medium is sprayed out of the first through hole 19, the heat conduction medium inside the heat conduction cavity 10 also gradually heats up and expands. The heat conduction medium inside the heat conduction cavity 10 can actively flow into the lower end of the connecting cylinder 13 through the liquid inlet holes 21, and then flow back to the storage cavity 16 through the one-way valve of the liquid inlet pipe 20, thereby forming a directional convection with the high-temperature heat conduction medium. The high-temperature heat-conducting medium is ejected from the upper first through hole 19, and the low-temperature heat-conducting medium flows into the lower liquid inlet hole 21, which improves the exchange efficiency of the hot and cold heat-conducting medium and transfers the heat from local hot spots to the entire area of ​​the heat sink 6 more quickly. The synergistic effect of the liquid inlet hole 21 and the connecting hole 11 of the support bar 9 not only realizes the circulation of the heat-conducting medium inside the heat-conducting cavity 10, but also allows the heat-conducting medium in different heat-conducting cavities 10 to be interchanged. Even if E-Comp and PTC are working at full load at the same time, each heat-conducting cavity 10 can maintain a balanced temperature, avoid heat dissipation failure caused by excessive local load, and improve the continuous and stable operation capability of the device under high power density conditions.

[0033] Example 6: Based on Example 4 or 5, a sliding plate 22 is provided below the fixed plate 18. The outer wall of the sliding plate 22 is slidably connected to the inner wall of the connecting cylinder 13. The upper surface of the sliding plate 22 is connected to the lower surface of the fixed plate 18 through the second spring 23. Second limiting rings 24 are provided at intervals below the sliding plate 22. The outer wall of the second limiting ring 24 is fixedly connected to the inner wall of the connecting cylinder 13. A plurality of second through holes 25 are evenly opened along the circumference of the side wall of the connecting cylinder 13. The second through holes 25 are located between the fixed plate 18 and the sliding plate 22.

[0034] The working principle and beneficial effects of the above technical solution are as follows: Initially, there is a gap between the sliding plate 22 and the fixed plate 18 and the second limiting ring 24, and the second through hole 25 is located within the initial gap area between the fixed plate 18 and the sliding plate 22. When the heat-conducting medium in the heat-conducting cavity 10 heats up and expands, in order to avoid excessive pressure in the heat-conducting cavity 10, the heat-conducting medium can flow into the buffer space between the fixed plate 18 and the sliding plate 22 through the second through hole 25. The flowing heat-conducting medium can push the sliding plate 22 to slide downwards, and the second spring 23 is stretched until the lower surface of the sliding plate 22 contacts the upper surface of the second limiting ring 24, and the volume of the buffer space reaches its maximum, thereby quickly absorbing the additional heat generated by the thermal expansion of the heat-conducting medium. The volume effectively relieves the pressure inside the heat-conducting cavity 10. When the temperature of wafer 2 decreases, the temperature of the heat-conducting medium inside the heat-conducting cavity 10 gradually decreases. Under the elastic force of the second spring 23, the second spring 23 drives the sliding plate 22 to slide upward and reset, thereby squeezing out part of the heat-conducting medium between the fixed plate 18 and the sliding plate 22 into the heat-conducting cavity 10, so that the distribution of the heat-conducting medium returns to the initial equilibrium state, preparing for the next thermal expansion pressure buffer. When E-Comp and PTC alternately start and stop, and the temperature of the heat-conducting medium fluctuates frequently, the sliding plate 22 can automatically complete the cycle of downward pressure relief and upward reset according to the temperature change. The response speed is fast and there is no energy consumption, which improves the stability of the device under complex dynamic conditions.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A dual-function power semiconductor device, characterized in that, include: The substrate (1), wafer (2), encapsulation body (3), multiple power pins (4), multiple signal pins (5) and heat sink (6) are arranged on the upper surface of the substrate (1). The power pins (4) and signal pins (5) are electrically connected to the substrate (1) and wafer (2). The encapsulation body (3) encapsulates the substrate (1) and wafer (2). The heat sink (6) is arranged on the lower surface of the substrate (1). A cavity is provided in the heat sink (6) and the cavity is filled with a thermally conductive medium.

2. The dual-in-one power semiconductor device according to claim 1, characterized in that, Multiple power pins (4) are distributed on the first side of the substrate (1) or on the first side and the second side, and multiple signal pins (5) are distributed on the second side of the substrate (1), with the first side and the second side being arranged opposite to each other.

3. The dual-in-one power semiconductor device according to claim 1, characterized in that, The power pin (4) and signal pin (5) both adopt a right-angle bent structure.

4. The dual-function power semiconductor device according to claim 1, characterized in that, The molding compound (3) encapsulates the periphery of the substrate (1) and the outer side of the wafer (2).

5. A dual-function power semiconductor device according to claim 1, characterized in that, A temperature sensor is disposed on the substrate (1), and the temperature sensor is electrically connected to at least two signal pins (5). The temperature sensor is a negative temperature coefficient thermistor.

6. The dual-function power semiconductor device according to claim 1, characterized in that, An oil inlet (7) is opened on the side wall of the heat sink (6). The oil inlet (7) is connected to the cavity. An internal thread is provided on the inner wall of the oil inlet (7). A sealing bolt (8) is provided inside the oil inlet (7). An external thread that matches the internal thread is provided on the outer wall of the sealing bolt (8). The sealing bolt (8) and the inner wall of the oil inlet (7) are sealed and connected by thread engagement.

7. A dual-function power semiconductor device according to claim 1, characterized in that, A number of support bars (9) are provided inside the cavity, and the support bars (9) divide the cavity into multiple heat-conducting cavities (10). The support bars (9) are evenly distributed along the width direction of the substrate (1). The upper surface of the support bar (9) is connected to the top wall of the cavity, and the lower surface of the support bar (9) is connected to the bottom wall of the cavity. A number of connecting holes (11) are provided through the bottom of the support bar (9). The connecting holes (11) are evenly distributed along the length direction of the support bar (9). The two ends of the connecting holes (11) are connected to the heat-conducting cavities (10) adjacent to both sides of the support bar (9).

8. A dual-in-one power semiconductor device according to claim 7, characterized in that, A heat-conducting assembly is provided inside the heat-conducting cavity (10). The heat-conducting assembly includes a heat-conducting seat (12) and a connecting cylinder (13). The upper end of the heat-conducting seat (12) is connected to the top wall of the heat-conducting cavity (10). The heat-conducting seat (12) is funnel-shaped. A connecting cylinder (13) is provided at the lower end of the heat-conducting seat (12). The upper end of the connecting cylinder (13) is connected to the inside of the heat-conducting seat (12). A first limiting ring (14) is provided inside the connecting cylinder (13). The outer wall of the first limiting ring (14) is fixedly connected to the inner wall of the connecting cylinder (13). A push plate (15) is provided below the first limiting ring (14). The outer wall of the push plate (15) is slidably connected to the inner wall of the connecting cylinder (13). The space above the push plate (15) of the connecting cylinder (13) is shaped with the space inside the heat-conducting seat (12). A storage chamber (16) is formed, and a heat-conducting medium is stored in the storage chamber (16). A push plate (15) is connected to the top wall of the storage chamber (16) through a first spring (17). A fixing plate (18) is set below the push plate (15). The outer wall of the fixing plate (18) is fixedly connected to the inner wall of the connecting cylinder (13). Several first through holes (19) are evenly opened along the circumference of the side wall of the connecting cylinder (13). The first through holes (19) are located between the fixing plate (18) and the first limiting ring (14). An inlet pipe (20) is set in the center of the push plate (15). The upper end of the inlet pipe (20) is connected to the storage chamber (16). The lower end of the inlet pipe (20) passes through the fixing plate (18) and is connected to the bottom of the fixing plate (18). A one-way valve is set in the inlet pipe (20).

9. A dual-function power semiconductor device according to claim 8, characterized in that, The lower end of the connecting cylinder (13) is connected to the bottom wall of the heat conduction cavity (10). Several liquid inlet holes (21) are provided near the lower outer wall of the connecting cylinder (13). The several liquid inlet holes (21) are arranged in a ring array about the central axis of the connecting cylinder (13).

10. A dual-function power semiconductor device according to claim 8, characterized in that, A sliding plate (22) is provided below the fixed plate (18). The outer wall of the sliding plate (22) is slidably connected to the inner wall of the connecting cylinder (13). The upper surface of the sliding plate (22) is connected to the lower surface of the fixed plate (18) through the second spring (23). A second limiting ring (24) is provided at intervals below the sliding plate (22). The outer wall of the second limiting ring (24) is fixedly connected to the inner wall of the connecting cylinder (13). Several second through holes (25) are evenly opened along the circumference of the side wall of the connecting cylinder (13). The second through holes (25) are located between the fixed plate (18) and the sliding plate (22).

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