Preparation method of phase change heat absorption power semiconductor device
By setting a phase change heat absorption structure on the heat transfer path of the power semiconductor device, using phase change materials and high thermal conductivity particles or porous skeletons, the problem of sharp temperature rise caused by short-term impact overload is solved, and the safety margin and device are improved Power density and reliability.
Patent Information
- Application Number
- CN202411246509.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2024-12-17
AI Technical Summary
Power semiconductor devices have large transient losses during short-term impact overload, resulting in a sharp rise in chip temperature. The existing heat dissipation system is complex and large in size, which limits the improvement of the power density and energy density of the device and is low in reliability.
Design a preparation method for phase change heat-absorbing power semiconductor devices. By setting a phase change heat-absorbing structure on the heat transfer path, including built-in and fusion phase change heat-absorbing structures, using phase change materials and highly thermally conductive particles or porous skeletons. Achieve rapid absorption and release of heat energy and reduce heat dissipation needs.
It significantly improves the safety margin of power semiconductor devices, simplifies heat dissipation needs, and improves the power density and reliability of power electronic devices.
Smart Images
Figure CN119153340A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of power semiconductor devices, and in particular to a method for preparing a phase-change heat-absorbing power semiconductor device. Background Art
[0002] During the actual operation of power semiconductor devices, short-term impact overloads such as short-term overload, surge and short circuit may occur. In some special application fields, such as solid-state circuit breakers and high-power pulse sources, power semiconductor devices mainly operate in intermittent short-term high-power pulse mode. Under short-term impact overload conditions, on the one hand, power semiconductor devices produce huge losses in a short period of time, causing the chip temperature to rise sharply, and power semiconductor devices face a high risk of electrothermal breakdown; on the other hand, short-term impact overloads usually last for a short time (seconds) and have a long interval (more than minutes). Therefore, the average loss of power semiconductor devices is low during operation. In theory, only simple and reliable natural convection or small air cooling is required. However, due to the large transient loss of power semiconductor devices, in order to alleviate the short-term sharp temperature rise of power semiconductor devices, they have to be equipped with a heat dissipation system with complex structure, large volume and mass, and low reliability, which seriously limits the improvement of the power density and energy density of the device.
[0003] Material phase change is a physical phenomenon that is ubiquitous in nature. During phase change, the temperature of the material is constant near the phase change temperature, accompanied by a large amount of energy release and absorption. The phase change enthalpy of the material is usually 2 to 3 orders of magnitude of its specific heat capacity. If the constant phase change temperature of the material and the phase change heat absorption characteristics are used, a phase change heat absorption material is set on the heat transfer path of the power semiconductor device to quickly absorb the energy dissipation during the short-term impact overload of the power semiconductor device, which may achieve the purpose of buffering the sharp temperature rise of the power semiconductor device, thereby significantly increasing the safety margin of the power semiconductor device during short-term impact overload applications, while simplifying the heat dissipation requirements and improving the power density and reliability of power electronic devices. Summary of the invention
[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned technology and provide a method for preparing a phase change heat absorption power semiconductor device to prepare a power semiconductor device with phase change heat absorption function, with high safety margin and low heat dissipation requirement.
[0005] To achieve the above-mentioned purpose, the method for preparing a phase change heat absorption power semiconductor device designed in the present invention clarifies the type and packaging structure of the power semiconductor device, analyzes the heat transfer path of the heating element of the power semiconductor device, and determines the phase change heat absorption structure, including a built-in phase change heat absorption structure and a fusion phase change heat absorption structure; for different phase change heat absorption structures, the material system and composite structure type of the phase change heat absorption structure are analyzed and clarified, and then the process flow of the phase change heat absorption power semiconductor device is proposed according to the phase change heat absorption structure, thereby completing the preparation of the phase change heat absorption power semiconductor device.
[0006] Preferably, in the built-in phase-change heat absorption structure, the phase-change heat absorption structure is built into the inner cavity of the power semiconductor device package, directly contacts the power semiconductor device chip and the ceramic copper cladding layer, and partially replaces the insulating silicone.
[0007] Preferably, in the fused phase-change heat absorption structure, the phase-change heat absorption structure is arranged at the bottom of the heat dissipation substrate of the power semiconductor device, and is integrated with the power semiconductor device by sintering or welding.
[0008] Preferably, in the built-in phase change heat absorption structure, a structure of phase change material composited with high thermal conductivity particles is adopted, the phase change material is used for absorbing and releasing thermal energy, and the high thermal conductivity particles are used for modifying the phase change material.
[0009] Preferably, in the fusion-type phase-change heat absorption structure, a structure of a phase-change material composite porous skeleton is adopted, in which the phase-change material is used for absorbing and releasing thermal energy, and the porous skeleton is used for the physical connection between the phase-change heat absorption structure and the substrate of the power semiconductor device and for the thermal conductivity enhancement modification of the phase-change material, so as to realize an integrated fusion connection between the phase-change material and the substrate, enhance the thermal conductivity of the phase-change material, and provide an ultra-large-scale heat exchange interface for the phase-change material.
[0010] Preferably, in the built-in phase change heat absorption structure, the phase change material is an organic hydrocarbon or an organic acid ester, including one or more of paraffin, lauric acid and palmitic acid, and the high thermal conductivity particles are high thermal conductivity insulating ceramic particles, including one or more of aluminum oxide, aluminum nitride and silicon carbide, and the high thermal conductivity particles are uniformly dispersed inside the phase change material.
[0011] Preferably, in the fusion-type phase-change heat-absorbing structure, the phase-change material is an organic hydrocarbon or organic acid or metal, including one or more of Bi-Cd-Sn-Pb-In, Bi-Sn-Pb-In, and the porous skeleton is a thermal conductivity enhancer, including foam copper, foam aluminum, foam nickel, foam silicon carbide metal or ceramic, the phase-change material is filled into the pores of the porous skeleton structure, and the thermal conductivity enhancer is continuously distributed in the phase-change material.
[0012] Preferably, in the built-in phase change heat absorption structure, a melt injection process is adopted to first complete the power semiconductor device chip welding, bonding wire / terminal ultrasonic welding and plastic sealing, then heat and melt the phase change material, add a certain amount of high thermal conductivity particles, stir and mix evenly to form a mixed melt for standby use, and finally inject the mixed melt into the plastic sealing module of the power semiconductor device to complete the production of the built-in phase change heat absorption structure.
[0013] Preferably, in the fusion-type phase-change heat-absorbing structure, a sintering or welding connection + vacuum liquid phase impregnation process is adopted. First, a power semiconductor device substrate and a porous skeleton are selected, and the porous skeleton is connected to the bottom of the substrate by a sintering or welding process. A coating is prepared on the surface of the porous skeleton by a gas-liquid deposition method to improve the wettability of the phase change material and the porous skeleton and enhance the thermal conductivity of the phase interface. Then, the packaging process of the power semiconductor device is continued on the porous skeleton-substrate. Finally, the phase change material is melted, and the phase change material melt is filled into the porous skeleton by a vacuum impregnation process to complete the preparation of the fusion-type phase-change heat-absorbing structure.
[0014] Preferably, after the preparation is completed, test devices for power semiconductor devices + water cooling, power semiconductor devices + built-in phase change heat absorption structure + water cooling, power semiconductor devices + fused phase change heat absorption structure + water cooling and power semiconductor devices + built-in phase change heat absorption structure + fused phase change heat absorption structure + water cooling are designed respectively, and temperature simulation and testing of power semiconductor device chips and substrates are carried out under constant power pulse conditions based on finite element models or temperature measurement tests to evaluate the suppression effect of different phase change heat absorption structure schemes on the transient temperature rise of power semiconductor modules.
[0015] Compared with the prior art, the present invention has the following advantages: the prepared power semiconductor module with phase change heat absorption function can, on the one hand, buffer the transient temperature impact of the power semiconductor module during short-term impact overload and improve the safety margin of the power semiconductor module; on the other hand, it can reduce the heat dissipation demand of the power semiconductor module and can adopt a heat dissipation method with simple structure and high reliability, thereby greatly improving the power density and reliability of the power electronic device. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic flow chart of the method for preparing a phase-change heat-absorbing power semiconductor device of the present invention;
[0017] Figure 2 Provide phase change heat absorption layout for power semiconductor devices with different packaging structures;
[0018] Figure 3 It is a schematic diagram of the structure of a built-in phase change heat absorption structure;
[0019] Figure 4 It is a schematic diagram of the structure of the fusion phase change heat absorption structure;
[0020] Figure 5 The present invention is a process flow chart for preparing a power semiconductor device with a built-in phase-change heat absorption structure;
[0021] Figure 6 The present invention is a process flow chart for preparing a fusion-type phase-change heat-absorbing structure power semiconductor device;
[0022] Figure 7It is a schematic diagram of the simulation comparison of the thermal buffering performance of the phase-change heat-absorbing IGBT module in the embodiment;
[0023] Figure 8 to Figure 11 The thermal buffering performance of phase-change endothermic IGBT modules with different structures is simulated and compared with the temperature field distribution after medium-power pulse loading for 4s. DETAILED DESCRIPTION
[0024] The present invention is further described in detail below in conjunction with specific embodiments.
[0025] A method for preparing a phase-change heat-absorbing power semiconductor device, which clarifies the type and packaging structure of the power semiconductor device, analyzes the heat transfer path of the heating element of the power semiconductor device, and determines the phase-change heat-absorbing structure, including a built-in phase-change heat-absorbing structure and a fusion phase-change heat-absorbing structure; for different phase-change heat-absorbing structures, the material system and composite structure type of the phase-change heat-absorbing structure are analyzed and clarified, and then a process flow of the phase-change heat-absorbing power semiconductor device is proposed based on the phase-change heat-absorbing structure, thereby completing the preparation of the phase-change heat-absorbing power semiconductor device.
[0026] Among them, in the built-in phase change heat absorption structure, the phase change heat absorption structure is built into the inner cavity of the power semiconductor device package, directly in contact with the power semiconductor device chip and the ceramic copper cladding layer, and partially replaces the insulating silicone. In the fusion phase change heat absorption structure, the phase change heat absorption structure is arranged at the bottom of the heat dissipation substrate of the power semiconductor device, and is integrated with the power semiconductor device through sintering or welding.
[0027] Specifically, in the built-in phase change heat absorption structure, a structure of phase change material composited with high thermal conductivity particles is adopted. The phase change material is used for absorbing and releasing thermal energy, and the high thermal conductivity particles are used for modifying the phase change material. The main function is to improve the thermal conductivity and thermal stability of the phase change material and reduce the supercooling of the phase change material.
[0028] In the fusion-type phase-change heat absorption structure, a structure of phase-change material composite porous skeleton is adopted. The phase-change material is used for absorbing and releasing heat energy, and the porous skeleton is used for the physical connection between the phase-change heat absorption structure and the substrate of the power semiconductor device and for the thermal conductivity enhancement modification of the phase-change material, so as to realize the integrated fusion connection between the phase-change material and the substrate, enhance the thermal conductivity of the phase-change material, and provide an ultra-large-scale heat exchange interface for the phase-change material.
[0029] In the built-in phase change heat absorption structure, since the phase change heat absorption structure is in direct contact with the current loop of the power semiconductor device, materials with good insulation, stability and compatibility must be used. The phase change material is an organic hydrocarbon or organic acid ester, including one or more of paraffin, lauric acid and palmitic acid. The high thermal conductivity particles are high thermal conductivity insulating ceramic particles, including one or more of aluminum oxide, aluminum nitride and silicon carbide. The high thermal conductivity particles are evenly dispersed inside the phase change material.
[0030] In the fusion-type phase-change heat-absorbing structure, since the phase-change heat-absorbing structure is placed at the bottom of the power semiconductor device substrate and is not in contact with the device current loop, the phase-change material is an organic hydrocarbon or organic acid ester or metal, including one or more of Bi-Cd-Sn-Pb-In, Bi-Sn-Pb-In, and the porous skeleton is a thermal conductivity enhancer, including foam copper, foam aluminum, foam nickel, foam silicon carbide metal or ceramic. The phase-change material is filled into the pores of the porous skeleton structure, and the thermal conductivity enhancer is continuously distributed in the phase-change material.
[0031] When the power semiconductor device is running, the chip temperature rises, and the heat energy is transferred to the phase change material through heat conduction. When the temperature of the phase change material reaches the phase change temperature point, the material undergoes a phase change and is accompanied by a heat absorption process, storing the heat energy dissipated and transferred by the power semiconductor device chip. When the power semiconductor device stops working, the chip temperature drops, and the heat energy is transferred from the phase change material to the external structure of the power semiconductor device to complete the heat dissipation.
[0032] like Figure 1 As shown, steps ① to ⑥ are the conventional packaging process flow of IGBT, steps A to F are the packaging process flow of the built-in phase change heat absorption structure power semiconductor device, and steps I to VII are the packaging process flow of the fusion phase change heat absorption structure power semiconductor device.
[0033] In the built-in phase change heat absorption structure, the melt injection process is adopted to first complete the power semiconductor device chip welding, bonding wire / terminal ultrasonic welding and plastic sealing, then heat and melt the phase change material, add a certain amount of high thermal conductivity particles, stir and mix evenly to form a mixed melt for standby use, and finally inject the mixed melt into the plastic sealing module of the power semiconductor device to complete the production of the built-in phase change heat absorption structure.
[0034] In the fusion-type phase-change heat-absorbing structure, sintering or welding connection + vacuum liquid phase impregnation process is adopted. First, a power semiconductor device substrate and a porous skeleton are selected, and the porous skeleton is connected to the bottom of the substrate through sintering or welding process. The coating is prepared on the surface of the porous skeleton by gas-liquid phase deposition method to improve the wettability of the phase change material and the porous skeleton and enhance the thermal conductivity of the phase interface. Then, the packaging process of the power semiconductor device is continued on the porous skeleton-substrate. Finally, the phase change material is melted, and the phase change material melt is filled into the porous skeleton by vacuum impregnation process to complete the preparation of the fusion-type phase-change heat-absorbing structure.
[0035] After the preparation is completed, test devices for power semiconductor devices + water cooling, power semiconductor devices + built-in phase change heat absorption structure + water cooling, power semiconductor devices + fused phase change heat absorption structure + water cooling and power semiconductor devices + built-in phase change heat absorption structure + fused phase change heat absorption structure + water cooling are designed respectively. Based on finite element models or temperature measurement tests, temperature simulation and experiments of power semiconductor device chips and substrates are carried out under constant power pulse conditions to evaluate the effect of different phase change heat absorption structure schemes on suppressing transient temperature rise of power semiconductor modules.
[0036] Take the Insulated Gate Bipolar Transistor (IGBT) module as an example:
[0037] First, analyze the heat transfer path and clarify the layout of the phase change heat absorption structure based on the IGBT specifications and models for short-term impact overload applications.
[0038] At present, the commonly used IGBTs are mainly divided into three mainstream packaging forms: discrete, modular and press-fit. Discrete IGBTs are usually single chips, and heat is mainly dissipated through heat conduction from the pins. Therefore, for such devices, transient thermal shock suppression can be performed by injecting phase change heat absorption materials into the package cavity. Modular IGBTs are usually high-power power devices with multiple chips in parallel. Heat conduction and heat dissipation are performed through multi-layer packaging materials. The heat flow mainly flows out of the device from the substrate. At the same time, modular IGBT devices usually have a larger package cavity, so phase change heat absorption structures can be arranged separately or simultaneously in the package cavity and at the bottom of the heat dissipation substrate. Press-fit IGBTs are double-sided substrate structures. The upper and lower substrates bear the electrical and thermal conductivity functions of the device. They usually need to be pressed together by a fixture. There is a large pressure on the substrate, which is not suitable for arranging a phase change heat absorption structure on the surface of the substrate. Press-fit devices have a closed package cavity, and a phase change heat absorption structure can be arranged in the cavity.
[0039] It can be seen that for the currently common packaging forms of power semiconductor devices, there are two phase change heat absorption structure layout schemes, namely the built-in phase change heat absorption structure and the fusion phase change heat absorption structure. According to the different packaging structures of power semiconductor devices, the two layout schemes can be used separately or simultaneously. Taking a certain power level IGBT module as an example, its two phase change heat absorption structures are as follows Figure 2 shown.
[0040] Design of built-in phase change heat absorption structure material system:
[0041] In the built-in phase change heat absorption structure arrangement scheme, the phase change heat absorption structure is directly in contact with the IGBT main current loop, so first of all, the selected phase change material and high thermal conductivity particles must have insulation performance; secondly, the phase change heat absorption structure in this scheme is in contact with the high electric field and high temperature area on the surface of the IGBT chip, so it must contain less impurity ions, have high thermal stability, be flame retardant, and be compatible with the organic matter of the chip insulation terminal, the surface metal layer, the bonding wire and other materials; thirdly, the phase change heat absorption structure in this scheme is in contact with the insulating silicone of the IGBT module, so the required phase change material and high thermal conductivity particles must be chemically compatible with the main components of the silicone and compatible with the preparation process. At present, the optional phase change materials mainly include organic hydrocarbons, organic acid esters, etc., and the optional thermal conductivity enhancers mainly include ceramics. For example, No. 48 refined paraffin (melting point 48°C) can be used as a phase change component, 5wt% Al2O3 nanoparticles can be added as high thermal conductivity particles, and the fusion and mixing can be prepared into a built-in phase change heat absorption structure.
[0042] Design of fusion phase change heat absorption structural material system:
[0043] In the fusion phase change heat absorption structure, the phase change heat absorption structure is connected to the bottom surface of the IGBT heat dissipation substrate. Therefore, the phase change material selected must be compatible with the substrate material (Al / SiC / Ni coating or Cu / Ni coating); secondly, the phase change heat absorption structure in this scheme is located outside the module, so the phase change material and porous skeleton must be non-toxic, non-volatile, anti-oxidation, corrosion-resistant, and biodegradable. At present, the optional phase change materials mainly include organic hydrocarbons with large phase change enthalpy, organic acid esters, and high thermal conductivity low melting point alloys. The optional porous skeletons mainly include metals such as copper and nickel with high thermal conductivity and good compatibility, and ceramics such as SiC and Si3N4. For example, the phase change material can be selected from Bi-Sn-Pb-In series low melting point alloys (melting point 46℃~58℃, density 8.5g / cm3~8.7g / cm3), and the porous skeleton can be selected from foam copper (parameters such as porosity and pore size distribution can be determined according to task requirements).
[0044] Composite structure types of built-in phase change heat absorption structure:
[0045] In the built-in phase change heat absorption structure, the phase change heat absorption structure covers the IGBT chip and the DBC board surface contact, and the IGBT packaging process requires ultrasonic bonding or liquid phase welding on the chip and DBC board surface. The surface morphology is complex, and the phase change structure needs to be prepared by melt casting + solidification molding. Therefore, it is suitable to use a dispersed particle phase thermal conductivity enhanced composite structure, such as Figure 3 As shown, the structure has a flexible appearance and a simple molding process.
[0046] Fusion phase change heat absorption structure composite structure type:
[0047] In the fusion phase change heat absorption structure, the phase change heat absorption structure contacts the flat bottom surface of the IGBT heat dissipation substrate. The phase change structure is directly connected to the bottom surface of the substrate by sintering or liquid phase welding. The surface morphology is regular and can be connected as a whole by sintering or liquid phase welding. Therefore, it is suitable for porous medium continuous phase thermal conductivity enhanced composite structure, such as Figure 4 As shown, the structure has a good thermal conductivity enhancement effect, eliminates the high thermal resistance interface between the IGBT module and the heat sink, and has a low thermal resistance from the IGBT module junction to the heat sink.
[0048] Preparation process of IGBT module with built-in phase change heat absorption structure
[0049] The phase change structure is in contact with IGBT chips, DBC boards, etc., and its surface has a complex morphology, so it is suitable to adopt the melt casting direct molding process. Figure 5 As shown, on the basis of the IGBT module completing the plastic encapsulation process steps, first weigh the phase change material and high thermal conductivity particles, mix and heat the phase change material and high thermal conductivity particles to melt; then use a stirring device to stir the mixed melt so that the high thermal conductivity particles are evenly dispersed in the phase change material melt; then inject the mixed melt into the IGBT module package cavity that has completed the plastic encapsulation process, keep it still and keep it warm; finally cool and solidify to form a dispersed particle thermal conductivity enhanced phase change heat absorption structure near the IGBT chip. On this basis, continue to complete the IGBT module glue filling process steps to complete the preparation of the package cavity type phase change heat absorption IGBT module.
[0050] Preparation process of fused phase change heat absorption structure IGBT module
[0051] The phase change structure is connected to the bottom surface of the IGBT module heat dissipation substrate, and its surface morphology is regular, so it can be formed by sintering / welding and other processes. Figure 6 As shown, after completing the basic processing and manufacturing of the IGBT module heat dissipation, firstly, according to the heat exchange requirements, a porous skeleton with a specific material, porosity, pore density and geometric size is selected, and the porous skeleton is connected to the bottom surface of the IGBT substrate by a sintering or liquid phase welding process; then, on this basis, the entire packaging process flow of the IGBT module is continued; then, the IGBT module with the porous skeleton is inverted, and an appropriate amount of phase change material is placed on it, and a sealed cavity cover with an exhaust hole is buckled on the porous skeleton and the phase change material, and the threaded holes on the edge of the IGBT module heat dissipation substrate are tightly matched with the sealed cavity to seal; a vacuum device is used to evacuate the cavity, and the sealed cavity is heated at the same time to melt the phase change material, and the phase change material penetrates into the porous structure under the action of its own gravity, the capillary force of the porous structure and the negative air pressure; the furnace is cooled to room temperature, the air pressure in the cavity is restored to normal pressure, the sealed cavity is removed, and the preparation of the substrate fusion phase change heat absorption IGBT module is completed.
[0052] Evaluation of thermal buffering effect of short-term impact overload of phase change heat-absorbing IGBT module
[0053] Based on two phase-change heat absorption IGBT module preparation methods, a built-in phase-change heat absorption structure IGBT module, a fused phase-change heat absorption structure IGBT module and a built-in phase-change heat absorption structure + fused phase-change heat absorption structure IGBT module were designed and prepared. Four finite element heat transfer models were constructed based on finite element simulation software such as ANSYS and COMSOL, including conventional IGBT module without phase-change heat absorption function, built-in phase-change heat absorption structure IGBT module, fused phase-change heat absorption structure IGBT module and a hybrid IGBT module with two phase-change heat absorption structures. Electrothermal simulation was carried out under short-term impact overload conditions, and the chip and substrate temperatures of the above four IGBT modules were quantitatively compared to complete the short-term impact overload thermal buffering efficiency evaluation of the phase-change heat absorption IGBT module.
[0054] Take a 1700V IGBT module as an example
[0055] First, it is clear that the built-in phase change heat absorption structure uses organic phase change materials (paraffin wax No. 48) and ceramic nanoparticles as high thermal conductivity particles (Al2O3); the fusion phase change heat absorption structure uses low melting point alloys (Bi-Sn-In-Pb system, 47 alloy) and metal porous materials (foam copper).
[0056] Secondly, four types of finite element models (models 1 to 4, respectively) were constructed, including those without phase change endothermic structure, those with built-in phase change endothermic structure, those with fused phase change endothermic structure, and those with both built-in phase change endothermic structure and fused phase change endothermic structure.
[0057] Again, a short power pulse with a heat flux density of 260 W / cm2 and a duration of 5 seconds is loaded on the IGBT chip; the convection heat transfer coefficient of the bottom of the substrate of the IGBT modules of Model 1 and Model 2 is set to 5000 W / (m2*K), and the convection heat transfer coefficient of the surface of the air-cooled heat dissipation fins of the IGBT modules of Model 3 and Model 4 is set to 50 W / (m2*K).
[0058] Secondly, the thermal conductivity of the built-in phase change heat absorption structure in Model 1 to Model 4 is set to 1W / (m*K), the phase change enthalpy is 200J / g, the phase change temperature is 48℃, and the supercooling degree is 3℃; the thermal conductivity of the fusion phase change heat absorption structure is set to 10W / (m*K), the phase change enthalpy is 75J / g, the phase change temperature is 47℃, and the supercooling degree is 3℃.
[0059] Finally, ignoring the micro-area self-heating convection, the fluid-solid coupling heat transfer finite element simulation was carried out to extract the average temperature and maximum temperature of the chip in the above four models.
[0060] like Figure 7 to Figure 11As shown, after the IGBT module with conventional cooling method is loaded with the power pulse for 4s, the maximum chip temperature is 174℃, and the average temperature rises from 40℃ to about 154.5℃; the IGBT module with built-in phase change heat absorption structure has a maximum temperature of 158℃ and an average temperature of 138℃, a decrease of about 16℃; the IGBT module with fusion phase change heat absorption structure has a maximum temperature of 160℃ and an average temperature of 140℃, a decrease of about 14℃; and the IGBT module with both built-in phase change heat absorption structure and fusion phase change heat absorption structure has a maximum temperature of about 150℃ and an average temperature of 130℃, a decrease of about 24℃, showing the best thermal buffering performance.
Claims
1. A method for preparing a phase-change endothermic power semiconductor device, characterized in that: Clarify the type and packaging structure of power semiconductor devices, analyze the heat transfer path of the heating element of the power semiconductor device, and determine the phase change heat absorption structure, including the built-in phase change heat absorption structure and the fusion phase change heat absorption structure; for different phase change heat absorption structures, analyze and clarify the material system and composite structure type of the phase change heat absorption structure, and then propose the process flow of phase change heat absorption power semiconductor devices based on the phase change heat absorption structure to complete the preparation of phase change heat absorption power semiconductor devices.
2. The method for preparing a phase-change heat-absorbing power semiconductor device according to claim 1, characterized in that: In the built-in phase change heat absorption structure, the phase change heat absorption structure is built into the inner cavity of the power semiconductor device package, in direct contact with the power semiconductor device chip and the ceramic copper cladding layer, and partially replaces the insulating silicone.
3. The method for preparing a phase-change endothermic power semiconductor device according to claim 1, characterized in that: In the fused phase-change heat absorption structure, the phase-change heat absorption structure is arranged at the bottom of the heat dissipation substrate of the power semiconductor device and is integrated with the power semiconductor device through sintering or welding.
4. The method for preparing a phase-change endothermic power semiconductor device according to claim 1, characterized in that: In the built-in phase change heat absorption structure, a structure of phase change material composited with high thermal conductivity particles is adopted. The phase change material is used for absorbing and releasing thermal energy, and the high thermal conductivity particles are used for modifying the phase change material.
5. The method for preparing a phase-change endothermic power semiconductor device according to claim 1, characterized in that: In the fusion-type phase-change heat absorption structure, a structure of phase-change material composite porous skeleton is adopted. The phase-change material is used for absorbing and releasing heat energy, and the porous skeleton is used for the physical connection between the phase-change heat absorption structure and the substrate of the power semiconductor device and for the thermal conductivity enhancement modification of the phase-change material, so as to realize the integrated fusion connection between the phase-change material and the substrate, enhance the thermal conductivity of the phase-change material, and provide an ultra-large-scale heat exchange interface for the phase-change material.
6. The method for preparing a phase-change heat-absorbing power semiconductor device according to claim 4, characterized in that: In the built-in phase change heat absorption structure, the phase change material is an organic hydrocarbon or an organic acid ester, including one or more of paraffin, lauric acid and palmitic acid, and the high thermal conductivity particles are high thermal conductivity insulating ceramic particles, including one or more of aluminum oxide, aluminum nitride and silicon carbide. The high thermal conductivity particles are evenly dispersed inside the phase change material.
7. The method for preparing a phase-change endothermic power semiconductor device according to claim 5, characterized in that: In the fusion-type phase-change heat-absorbing structure, the phase-change material is an organic hydrocarbon or organic acid or metal, including one or more of Bi-Cd-Sn-Pb-In, Bi-Sn-Pb-In, and the porous skeleton is a thermal conductivity enhancer, including foam copper, foam aluminum, foam nickel, foam silicon carbide metal or ceramic. The phase-change material is filled into the pores of the porous skeleton structure, and the thermal conductivity enhancer is continuously distributed in the phase-change material.
8. The method for preparing a phase-change heat-absorbing power semiconductor device according to claim 1, characterized in that: In the built-in phase change heat absorption structure, the melt injection process is adopted to first complete the power semiconductor device chip welding, bonding wire / terminal ultrasonic welding and plastic sealing, then heat and melt the phase change material, add a certain amount of high thermal conductivity particles, stir and mix evenly to form a mixed melt for standby use, and finally inject the mixed melt into the plastic sealing module of the power semiconductor device to complete the production of the built-in phase change heat absorption structure.
9. The method for preparing a phase-change endothermic power semiconductor device according to claim 1, characterized in that: In the fusion-type phase-change heat-absorbing structure, sintering or welding connection + vacuum liquid phase impregnation process is adopted. First, a power semiconductor device substrate and a porous skeleton are selected, and the porous skeleton is connected to the bottom of the substrate through sintering or welding process. The coating is prepared on the surface of the porous skeleton by gas-liquid phase deposition method to improve the wettability of the phase change material and the porous skeleton and enhance the thermal conductivity of the phase interface. Then, the packaging process of the power semiconductor device is continued on the porous skeleton-substrate. Finally, the phase change material is melted, and the phase change material melt is filled into the porous skeleton by vacuum impregnation process to complete the preparation of the fusion-type phase-change heat-absorbing structure.
10. The method for preparing a phase-change endothermic power semiconductor device according to claim 1, characterized in that: After the preparation is completed, test devices for power semiconductor devices + water cooling, power semiconductor devices + built-in phase change heat absorption structure + water cooling, power semiconductor devices + fused phase change heat absorption structure + water cooling and power semiconductor devices + built-in phase change heat absorption structure + fused phase change heat absorption structure + water cooling are designed respectively. Based on finite element models or temperature measurement tests, temperature simulation and experiments of power semiconductor device chips and substrates are carried out under constant power pulse conditions to evaluate the effect of different phase change heat absorption structure schemes on suppressing transient temperature rise of power semiconductor modules.