High-thermal-conductivity aluminum oxide ceramic substrate for quick-response IGBT module and preparation method thereof

Abstract

The invention discloses a quick-response high-thermal-conductivity aluminum oxide ceramic substrate for an IGBT module and a preparation method of the quick-response high-thermal-conductivity aluminum oxide ceramic substrate, and relates to the technical field of ceramic materials.The preparation method of the quick-response high-thermal-conductivity aluminum oxide ceramic substrate for the IGBT module comprises the steps that S1, a dispersing agent, aluminum oxide powder and a sintering aid are added into a solvent to be evenly mixed, and primary slurry is obtained, performing primary ball milling on the primary slurry, wherein the weight ratio of the dispersing agent to the alumina powder to the sintering aid to the solvent is 3: 95: 5: 40; s2, a binder and a plasticizer are added into the primary slurry for secondary ball milling, aluminum oxide tape casting slurry is obtained, and the weight ratio of the primary slurry to the binder to the plasticizer is 286: 20: 3. The preparation method has the beneficial effects that the aluminum oxide ceramic substrate prepared by adopting the technical scheme of the invention has the advantage of high heat conduction efficiency, so that the heat dissipation efficiency and the response speed of an IGBT module are greatly improved, and the application requirement of the market on a high-performance IGBT module is effectively met.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module and a preparation method thereof. Background Art

[0002] As a key component in power electronics technology, IGBT modules are widely used in electric vehicles, smart grids, high-speed railways and other fields. These applications put forward higher requirements on the heat dissipation performance of IGBT modules. At present, although the alumina ceramic substrates on the market have good electrical insulation and mechanical strength, their low thermal conductivity limits the heat dissipation efficiency and response speed of IGBT modules. Therefore, it is necessary to develop a high thermal conductivity alumina ceramic substrate for insulated gate bipolar transistor (IGBT) modules to meet the application requirements of IGBT modules. Summary of the invention

[0003] The main purpose of the present invention is to propose a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module and a preparation method thereof, aiming to solve the problem that the existing alumina ceramic substrate has low thermal conductivity efficiency, which affects the heat dissipation efficiency and response speed of the IGBT module.

[0004] To solve the above problems, the present invention proposes a method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module, comprising: S1, adding a dispersant, alumina powder, and a sintering aid into a solvent and mixing them evenly to obtain a primary slurry, and then performing a primary ball milling on the primary slurry, wherein the weight ratio of the dispersant, alumina powder, sintering aid, and solvent is 3:95:5:40; S2, adding a binder and a plasticizer to the primary slurry for secondary ball milling to obtain an alumina tape casting slurry, wherein the weight ratio of the primary slurry, the binder, and the plasticizer is 286:20:3; S3, degassing the alumina tape casting slurry; S4, tape-casting the alumina tape-casting slurry after degassing on a tape-casting machine, and drying to obtain a tape-casting green body; S5, subjecting the tape-cast green body to isostatic pressing in a warm isostatic press; S6, sequentially performing binder removal, sintering, grinding and polishing on the tape-cast green body after isostatic pressing to obtain an alumina ceramic substrate.

[0005] In one embodiment, the solvent is one or more of ethanol, isopropanol, methyl ethyl ketone, trichloroethylene, benzene, toluene, and xylene; The dispersant is one or more of oleic acid, triethyl phosphate, and castor oil; The binder is polyvinyl butyral; The plasticizer is one or more of dibutyl phthalate, polyethylene glycol, and dioctyl phthalate; The sintering aid is Y 2 O 3 、MgO、SiO 2 、ZrO 2 , CaO or more; The alumina powder has a particle size of 0.8 microns to 1.5 microns and a purity of ≥99.9%; The isostatic pressing treatment has a pressure of 50Mpa-80Mpa and a temperature of 60°C-80°C; The debinding temperature is 500°C-700°C, the debinding rate is 1°C / min, and the sintering temperature is 1550-1650°C.

[0006] In one embodiment, the tape-cast green body is transported from the tape-casting machine to the warm isostatic press by a flatbed trolley, on which a carrying plate is detachably and horizontally fixedly mounted. The carrying plate can slide horizontally on the flatbed trolley, and a plurality of tape-cast green bodies are placed.

[0007] In one embodiment, the tape casting machine has a conveyor belt, and the tape casting green body is conveyed to the supporting plate by the conveyor belt.

[0008] In one embodiment, the warm isostatic press comprises: The hot isostatic pressure box has a support leg, a rotating shaft and a brake motor at its lower end, the rotating shaft is fixedly connected to a mounting seat, the mounting seat is provided with a guide plate, a push-pull device, a rotating motor and a shaft sleeve, the guide plate, the push-pull device are fixedly connected to the mounting seat, the rotating motor is slidably connected to the mounting seat, the shaft sleeve is transmission-connected to the rotating motor, and the shaft sleeve is driven to rotate by the rotating motor, the push-pull device is connected to the rotating motor, and is used to drive the rotating motor to slide on the mounting seat, the brake motor is transmission-connected to the rotating shaft, and is used to drive the mounting seat to rotate around the rotating shaft, a box door is provided on the side of the hot isostatic pressure box, when the brake motor drives the mounting seat to rotate to the lower end of the hot isostatic pressure box, the box door can be opened, when the brake motor drives the mounting seat to rotate to the door of the hot isostatic pressure box, the guide plate is horizontal, and the upper surface of the guide plate is flush with the lower surface of the bearing plate on the flatbed trolley, and the bearing plate on the flatbed trolley can slide horizontally onto the guide plate; The lifting mechanism is arranged in the warm isostatic pressing box. A plurality of slides are arranged on the lifting mechanism. The plurality of slides are lifted and lowered under the drive of the lifting mechanism. When a certain slide is lifted and lowered to be flush with the horizontal guide plate, the bearing plate on the guide plate can slide horizontally onto the slide.

[0009] In one embodiment, the lifting mechanism has a pair and is symmetrically arranged on the two side walls of the warm isostatic pressure box, and the bearing plate is located between the pair of lifting mechanisms; The lifting mechanism comprises: A plurality of installation cylinders are arranged at intervals, the plurality of installation cylinders are coaxial, and the plurality of installation cylinders are fixedly connected by a connecting plate, the connecting plate is located in the installation cylinder, a slideway is defined between two adjacent installation cylinders, a plurality of sliders are slidably installed in the slideway along the circumference of the installation cylinder, and each slider is fixedly connected to a slide seat; The baffle is fixedly connected to the mounting cylinder and the warm isostatic pressure box; The second rotating shaft is located in the installation cylinder and is rotatably connected to the baffle. A sprocket is arranged on the second rotating shaft. There are at least two second rotating shafts, which are arranged at the upper and lower ends of the installation cylinder. A chain is wound around the sprocket, and the chain is fixedly connected to the slider. The shaft block is coaxially fixedly installed at one end of the second rotating shaft close to the door. When the guide plate is horizontal, the push-pull device pushes the shaft sleeve to move and can be connected with the shaft block through plug-in transmission; The lifting limit device is vertically fixed on the inner bottom surface of the warm isostatic pressure box and is located directly below the slide seats at both ends of the bearing plate. The lifting limit device can lift and fix the slide seat at the lower end.

[0010] In one embodiment, S5, subjecting the tape-cast green body to isostatic pressing in a warm isostatic press, comprises: S51, controlling the conveyor belt of the tape casting machine to rotate and horizontally transfer the dried tape casting green body to a carrying plate on the flat cart; S52, after the carrying plate on the flatbed cart is fully loaded with the tape-cast green body, the flatbed cart is moved close to the warm isostatic press; S53, opening the box door, controlling the brake motor to drive the mounting seat to rotate around the rotating shaft until the guide plate is horizontal, and the mounting seat is located at the door of the warm isostatic pressure box; S54, control the push-pull device to push the shaft sleeve to move and connect with the shaft block plug-in transmission, start the rotating motor to drive the rotating shaft 2 to rotate and adjust the position of the slide seat until the front end slide seat in the chain rotation direction is flush with the guide plate; S55, pushing the load-bearing plate to slide horizontally from the flatbed cart, and the load-bearing plate slides into the slide seat through the guide plate; S56, controlling the rotary motor to drive the second rotating shaft to rotate so that the next slide is flush with the guide plate, and then pushing the load plate on the next flatbed cart to slide horizontally, and the load plate slides into the slide through the guide plate; S57, repeat S56 until all slides have bearing plates, then control the push-pull device to drive the shaft sleeve and shaft block to separate and reset, then control the brake motor to drive the mounting seat to rotate and reset, and finally close the box door to perform isostatic pressing.

[0011] In one embodiment, before controlling the push-pull device to drive the shaft sleeve to separate from the shaft block in S57, the lifting and limiting device is first controlled to lift and fix the sliding seat at the lowermost end.

[0012] In one embodiment, after the static pressure treatment in S57 is completed, S53 is performed first, and then the push-pull device is controlled to push the sleeve to move and connect with the shaft block plug-in transmission, and then the jacking limit device is controlled to descend and reset, and then the rotating motor is started to drive the rotating shaft 2 to rotate and adjust the position of the slide, so that the slide and the guide plate are flush at the same height, and finally the load-bearing plate on the slide is pulled out horizontally.

[0013] In addition, the present invention also proposes a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module, which is prepared by using any of the above-mentioned methods for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module.

[0014] Beneficial effect: The alumina ceramic substrate prepared by the technical solution of the present application has the advantage of high thermal conductivity efficiency, thereby greatly improving the heat dissipation efficiency and response speed of the IGBT module, effectively meeting the market application demand for high-performance IGBT modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 is a SEM surface image of the alumina ceramic substrate prepared in Example 1; Figure 2 is a SEM cross-sectional view of the alumina ceramic substrate prepared in Example 1; Figure 3 It is a structural schematic diagram of a flatbed cart and a warm isostatic press of the present invention; Figure 4 yes Figure 3 A magnified view of part A in FIG. Figure 5 yes Figure 3 DD section view in; Figure 6 yes Figure 5 An enlarged view of part B; Figure 7 It is the front view of the warm isostatic pressing box; Figure 8 It is a structural diagram of the lifting mechanism; Fig. 9 yes Figure 8 EE cross-sectional view in; Fig.10 yes Fig. 9 Enlarged view of part C in .

[0017] The accompanying drawings are described as follows: 1. Tape casting machine; 2. Tape casting green body; 3. Conveyor belt; 4. Flatbed cart; 5. Loading plate; 6. Locking screw; 7. Warm isostatic pressure box; 8. Support legs; 9. Box door; 10. Brake motor; 11. Mounting seat; 12. Rotating shaft 1; 13. Push-pull device; 14. Rotating motor; 15. Bushing; 16. Guide plate; 17. Baffle; 18. Mounting cylinder; 19. Slide; 20. Connecting plate; 21. Rotating shaft 2; 22. Sprocket; 23. Shaft block; 24. Chain; 25. Slider; 26. Sliding seat; 27. Groove; 28. Connecting block; 29. ​​Lifting limit device. DETAILED DESCRIPTION

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

[0019] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] The present invention proposes a method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module effectively improves the density of the alumina ceramic, reduces the porosity of the alumina ceramic, and improves the thermal conductivity efficiency of the alumina ceramic through isostatic pressing treatment, thereby greatly improving the heat dissipation efficiency and response speed of the IGBT module, effectively meeting the market application needs for high-performance IGBT modules.

[0023] Specifically, in one embodiment of the invention, the method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module comprises: S1. Add dispersant, alumina powder and sintering aid into solvent and mix well to obtain primary slurry, then perform initial ball milling on the primary slurry. The weight ratio of dispersant, alumina powder, sintering aid and solvent is 3:95:5:40. The ball milling time is determined according to the total amount of primary slurry. The ball milling can be stopped as long as the particle size reaches the specified requirement. S2, adding a binder and a plasticizer to the primary slurry for secondary ball milling to obtain an alumina tape casting slurry, wherein the weight ratio of the primary slurry, the binder, and the plasticizer is 286:20:3, and the ball milling time is determined according to the total amount of the primary slurry. The ball milling can be stopped as long as the particle size reaches the specified requirement; S3, degassing the alumina tape casting slurry; S4, tape-casting the alumina tape-casting slurry after degassing on a tape-casting machine 1, and drying to obtain a tape-casting green body 2; S5, subjecting the tape-cast green body 2 to isostatic pressing in a warm isostatic press to eliminate defects and bubbles in the tape-cast green body 2, thereby increasing the density of the tape-cast green body 2, thereby increasing the thermal conductivity of the alumina ceramic substrate, greatly improving the heat dissipation efficiency and response speed of the IGBT module, and effectively meeting the market demand for high-performance IGBT modules; S6, sequentially debinding, sintering, grinding and polishing the tape-cast green body 2 after isostatic pressing to obtain an alumina ceramic substrate.

[0024] In this embodiment, the solvent is one or more of ethanol, isopropanol, methyl ethyl ketone, trichloroethylene, benzene, toluene, and xylene; The dispersant is one or more of oleic acid, triethyl phosphate, and castor oil; The binder is polyvinyl butyral; The plasticizer is one or more of dibutyl phthalate, polyethylene glycol, and dioctyl phthalate; The sintering aid is Y 2 O 3 、MgO、SiO 2 、ZrO 2 , CaO or more; The alumina powder has a particle size of 0.8 microns to 1.5 microns and a purity of ≥99.9%; The isostatic pressing treatment has a pressure of 50Mpa-80Mpa and a temperature of 60°C-80°C; The debinding temperature is 500°C-700°C, the debinding rate is 1°C / min, and the sintering temperature is 1550-1650°C.

[0025] In the preparation method of a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module of the present embodiment, a cationic mineralizer is selected as a sintering aid, and a low-temperature rapid sintering technology and an isostatic pressing technology are used to promote the rapid densification of the alumina ceramic substrate and improve the thermal conduction efficiency. The thermal conductivity of the alumina ceramic substrate can reach above 30W / mK, achieving excellent heat dissipation efficiency and response speed. The subsequent grinding and polishing processing technology further eliminates the surface defects of the alumina ceramic substrate and improves the heat transfer efficiency. The alumina ceramic substrate can quickly transfer heat in a high-frequency switching state to maintain the temperature stability of the IGBT module, while maintaining excellent electrical insulation and mechanical strength, fully meeting the needs of efficient heat dissipation and rapid response of modern power electronic devices.

[0026] In addition, in order to improve the production efficiency of the alumina ceramic substrate, the tape-cast green body 2 in S4 and S5 can be transported from the tape-casting machine 1 to the warm isostatic press by a flatbed trolley 4, on which a carrying plate 5 is detachably and horizontally fixedly mounted, such as Figure 3 and Figure 4As shown, the supporting plate 5 is detachably and horizontally fixedly connected to the flatbed trolley 4 by means of locking screws 6. The supporting plate 5 can slide horizontally on the flatbed trolley 4. A plurality of tape-cast green pieces 2 are placed on the supporting plate 5. The tape-casting machine 1 has a conveyor belt 3, through which the dried tape-cast green pieces 2 are transported to the supporting plate 5.

[0027] In this embodiment, if Figure 3-Figure 10 As shown, the warm isostatic press comprises: a warm isostatic pressure box 7 and a lifting mechanism, the lower end of the warm isostatic pressure box 7 is provided with a support leg 8, a rotating shaft 12 and a brake motor 10, the support leg 8 is used to support and fix the warm isostatic pressure box 7, the brake motor 10 is fixedly connected to the warm isostatic pressure box 7, the rotating shaft 12 is rotationally connected to the warm isostatic pressure box 7, and the rotating shaft 12 is fixedly connected to a mounting seat 11, as shown in FIG. Figure 3 and Figure 5 As shown, the mounting seat 11 is provided with a guide plate 16, a push-pull device 13, a rotating motor 14 and a sleeve 15. The guide plate 16 and the push-pull device 13 are fixedly connected to the mounting seat 11, the rotating motor 14 is slidably connected to the mounting seat 11, the sleeve 15 is transmission-connected to the rotating motor 14, and the sleeve 15 is driven to rotate by the rotating motor 14. The push-pull device 13 is connected to the rotating motor 14 to drive the rotating motor 14 to slide on the mounting seat 11, and the brake motor 10 is transmission-connected to the rotating shaft 12 to drive the mounting seat 11 to rotate around the rotating shaft 12. Figure 3 Rotate between the solid line position and the dashed line position.

[0028] In this embodiment, if Figure 3 and Figure 5 As shown, a door 9 is provided on the side of the warm isostatic box 7. The door 9 can be opened only when the brake motor 10 drives the mounting seat 11 to rotate to the lower end of the warm isostatic box 7. Figure 3 and Figure 5 As shown, when the brake motor 10 drives the mounting base 11 to rotate to the door of the warm isostatic pressure box 7, the guide plate 16 is horizontal, and the upper surface of the guide plate 16 is flush with the lower surface of the supporting plate 5 on the flatbed cart 4. With this design, the supporting plate 5 on the flatbed cart 4 can slide horizontally onto the guide plate 16.

[0029] In this embodiment, the lifting mechanism is arranged in the warm isostatic pressing box 7, and a plurality of slides 26 are arranged on the lifting mechanism. The plurality of slides 26 are raised and lowered under the drive of the lifting mechanism. When a certain slide 26 is raised and lowered to be flush with the horizontal guide plate 16, the supporting plate 5 on the guide plate 16 can slide horizontally onto the slide 26, and then the lifting mechanism drives the next slide 26 to be raised and lowered to be flush with the horizontal guide plate 16. By repeating the above-mentioned actions, a plurality of supporting plates 5 can be quickly loaded into the warm isostatic pressing box 7, and a plurality of tape-cast green sheets 2 are placed on each supporting plate 5. Therefore, a large number of tape-cast green sheets 2 can be quickly and efficiently loaded into the warm isostatic pressing box 7. Compared with the existing method of loading the tape-cast green sheets 2 into the warm isostatic pressing box 7 by manpower, the loading time of the warm isostatic pressing box 7 is greatly shortened, and the production efficiency of the alumina ceramic substrate is improved.

[0030] In this embodiment, there is a pair of lifting mechanisms, which are symmetrically arranged on the inner side walls of the warm isostatic pressure box 7, and the carrying plate 5 is located between the pair of lifting mechanisms. Figure 5-Figure 10 As shown, the lifting mechanism includes: a baffle 17, a rotating shaft 21, a shaft block 23, a lifting limit device 29, and a plurality of installation cylinders 18 arranged at intervals. The plurality of installation cylinders 18 are coaxial, and the plurality of installation cylinders 18 are fixedly connected by a connecting plate 20. The connecting plate 20 is located in the installation cylinder 18, and a slideway 19 is defined between two adjacent installation cylinders 18. A plurality of sliders 25 are slidably installed in the slideway 19 along the circumference of the installation cylinder 18, and each slider 25 is fixedly connected to a slide seat 26, as shown in FIG. Figure 7 and Figure 8 As shown, a plurality of bearing plates 5 are placed from top to bottom between a pair of lifting mechanisms, and both left and right ends of the lower surface of each bearing plate 5 are supported by a slide seat 26, and a slide seat 26 is fixedly connected to a plurality of sliders 25 of the same height as it, as shown in FIG. Figure 5 , Figure 6 , Fig. 9 and Fig.10 As shown, there are multiple slideways 19, so there are multiple sliders 25 at the same height position. The multiple sliders 25 can be fixedly connected to a slide seat 26. With this design, the length of the slide seat 26 can be designed to be longer, which is conducive to expanding the length of the supporting plate 5, so that more cast green bodies 2 can be placed on a single supporting plate 5, and the production efficiency of the alumina ceramic substrates can be further improved.

[0031] In this embodiment, if Figure 5-Figure 10As shown, the baffle 17 is fixedly connected to the mounting cylinder 18 and the warm isostatic pressure box 7, and the mounting cylinder 18 is supported and fixed by the baffle 17; the rotating shaft 21 is located in the mounting cylinder 18 and is rotatably connected to the baffle 17, and a sprocket 22 is arranged on the rotating shaft 21, and there are at least two rotating shafts 21, which are respectively arranged at the upper and lower ends in the mounting cylinder 18, and a chain 24 is wound around the sprocket 22, and the chain 24 is fixedly connected to the slider 25; the rotation of the rotating shaft 21 drives the chain 24 to rotate through the sprocket 22, and then drives the slider 25 and the slide seat 26 to slide around the slideway 19 along the circumference of the mounting cylinder 18, and the sliding trajectory is a runway circle. Since the slide seat 26 slides around the outer wall of the mounting cylinder 18, the mounting cylinder 18 and the inner wall of the warm isostatic pressure box 7 need to maintain a certain distance, so the mounting cylinder 18 is supported and fixed by the baffle 17, and the baffle 17 can also be fixedly connected to the inner wall of the warm isostatic pressure box 7 through the connecting block 28.

[0032] In this embodiment, in order to prevent the connecting plate 20 from interfering with the rotation of the chain 24, Fig.10 As shown, the connecting plate 20 is provided with a groove 27 for the chain 24 to pass through.

[0033] In this embodiment, if Figure 5 As shown, the shaft block 23 is coaxially fixedly installed at one end of the rotating shaft 21 close to the door. When the guide plate 16 is horizontal, the push-pull device 13 pushes the shaft sleeve 15 to move and can be connected to the shaft block 23 for plug-in transmission, so as to drive the rotating shaft 21 to rotate through the rotating motor 14.

[0034] In this embodiment, if Figure 7 As shown, the lifting limit device 29 is vertically fixed on the inner bottom surface of the warm isostatic pressure box 7 and is located directly below the slides 26 at both ends of the bearing plate 5. With this design, the lifting limit device 29 can lift and fix the lowermost slide 26 to prevent the bearing plate 5 from pressing down the slide 26 after the sleeve 15 is separated from the shaft block 23, causing the sprocket 22 and the rotating shaft 21 to rotate erroneously.

[0035] In this embodiment, S5, subjecting the tape-cast green body 2 to isostatic pressing in a warm isostatic press, comprises: S51, controlling the conveyor belt 3 of the tape casting machine 1 to rotate and horizontally transfer the dried tape casting green body 2 to the carrying plate 5 on the flatbed cart 4; S52, after the carrying plate 5 on the flatbed trolley 4 is fully loaded with the tape-cast green body 2, the flatbed trolley 4 is moved close to the warm isostatic press, and then the next flatbed trolley 4 is moved close to the conveyor belt 3 of the tape-casting machine 1, and the dried tape-cast green body 2 is continuously transferred to the carrying plate 5 on the flatbed trolley 4, so multiple flatbed trolleys 4 are required; S53, open the box door 9, control the brake motor 10 to drive the mounting seat 11 to rotate around the rotating shaft 12 until the guide plate 16 is horizontal, and the mounting seat 11 is located at the door of the warm isostatic box 7; S54, control the push-pull device 13 to push the sleeve 15 to move and connect with the shaft block 23, start the rotating motor 14 to drive the rotating shaft 21 to rotate and adjust the position of the slide 26, until the front end slide 26 of the chain 24 is flush with the guide plate 16 in the rotation direction, and the chain 24 rotates in the same direction as Figure 8 As shown; S55, pushing the carrying plate 5 to start sliding horizontally from the flatbed cart 4, and the carrying plate 5 slides into the slide seat 26 through the guide plate 16; S56, control the rotating motor 14 to drive the rotating shaft 21 Figure 8 The chain 24 shown rotates in the direction of rotation so that the next slide 26 is flush with the guide plate 16, and then pushes the load plate 5 on the next flatbed cart 4 to slide horizontally, and the load plate 5 passes through the guide plate 16 and slides into the slide 26; S57, repeat S56 until all the slides 26 have the bearing plates 5. Figure 7 As shown, at this time, the warm isostatic box 7 is filled with the bearing plate 5, and then the push-pull device 13 is controlled to drive the sleeve 15 and the shaft block 23 to separate and reset, and then the brake motor 10 is controlled to drive the mounting seat 11 to rotate and reset to Figure 3 At the position shown by the middle dotted line, the box door 9 is finally closed for isostatic pressing treatment. Compared with the existing method of loading the tape-cast green body 2 into the warm isostatic pressing box 7 by manpower, this method greatly shortens the loading time of the warm isostatic pressing box 7 and improves the production efficiency of the alumina ceramic substrate.

[0036] In this embodiment, before controlling the push-pull device 13 in S57 to drive the shaft sleeve 15 to separate from the shaft block 23, the lifting limit device 29 is first controlled to lift and fix the slide 26 at the lower end, so as to prevent the bearing plate 5 from pressing down the slide 26 after the shaft sleeve 15 is separated from the shaft block 23, causing the sprocket 22 and the rotating shaft 21 to rotate incorrectly and cause a dangerous accident.

[0037] In this embodiment, after the medium static pressure treatment in S57 is completed, S53 is performed first, and then the push-pull device 13 is controlled to push the sleeve 15 to move and connect with the shaft block 23 for plug-in transmission, and then the jacking limit device 29 is controlled to descend and reset, and then the rotating motor 14 is started to drive the rotating shaft 21 to rotate and adjust the position of the slide 26, so that each slide 26 is flush with the guide plate 16 in turn. When the slide 26 is flush with the guide plate 16, the supporting plate 5 on the slide 26 can be pulled horizontally onto the flatbed cart 4. This unloading method is efficient, fast, simple and convenient, and further improves the production efficiency of alumina ceramic substrates.

[0038] In addition, the present invention also proposes a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module, which is prepared by using any of the above-mentioned methods for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module.

[0039] The following describes in detail a method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module of the present invention through a plurality of embodiments and comparative examples. Embodiment 1:

[0040] In this embodiment, the method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module comprises: S1. Add dispersant, alumina powder and sintering aid into solvent and mix well to obtain primary slurry. The solvent is a mixture of ethanol, isopropanol and xylene. The mass ratio of ethanol, isopropanol and xylene is 5:4:1. The total weight of the solvent is 80 g. The dispersant is triethyl phosphate with a mass of 6 g. The alumina powder has a mass of 190 g and the sintering aid is 4 g. 2 O 3 and 6gMgO, and then the primary slurry was initially ball-milled, the weight ratio of dispersant, alumina powder, sintering aid, and solvent was 3:95:5:40, and the ball-milling time was 24h; S2, adding a binder and a plasticizer to the primary slurry for secondary ball milling, the binder is polyvinyl butyral, the mass is 20g, the plasticizer is dibutyl phthalate, the mass is 3g, the ball milling time is 24h, and an alumina tape casting slurry is obtained, and the weight ratio of the primary slurry, the binder, and the plasticizer is 286:20:3; S3, degassing the alumina tape casting slurry; S4, tape-casting the alumina tape-casting slurry after degassing on a tape-casting machine 1, and drying to obtain a tape-casting green body 2; S5, subjecting the tape-cast green body 2 to isostatic pressing in a warm isostatic press, wherein the isostatic pressing temperature and pressure are 60° C. and 60 MPa, respectively, to eliminate defects and bubbles in the tape-cast green body 2, and to increase the density of the tape-cast green body 2, thereby increasing the thermal conductivity of the alumina ceramic substrate, greatly improving the heat dissipation efficiency and response speed of the IGBT module, and effectively meeting the market demand for high-performance IGBT modules; S6. Debinding, sintering, grinding and polishing the tape-cast green body 2 after isostatic pressing are performed in sequence to obtain an alumina ceramic substrate. The debinding temperature is 600° C., the debinding rate is 1° C. / min, the sintering temperature is 1550° C., and the heat preservation is required for 2 hours after sintering.

[0041] In this embodiment, the alumina powder has a particle size of 0.8 microns to 1.5 microns and a purity of ≥99.9%; Embodiment 2:

[0042] The difference between the second embodiment and the first embodiment is only that: The sintering aid is 2g Y 2 O 3 , 4gCaO and 4gMgO; The isostatic pressing temperature is 70°C; The sintering temperature is 1570°C. Embodiment three:

[0043] The difference between the third embodiment and the first embodiment is only that: The sintering aid is 2g Y 2 O 3 , 2gCaO, 2gSiO 2 and 4gMgO; The isostatic pressing temperature and pressure are 80°C and 80Mpa respectively; The sintering temperature is 1600°C.

[0044] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is only that: No sintering aids; The sintering temperature is 1650°C.

[0045] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is only that: there is no isostatic pressing treatment.

[0046] The performance test results of the alumina ceramic substrates prepared in the above-mentioned Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 are as follows:

[0047] It can be seen from the above table that the density and thermal conductivity of the alumina ceramic substrate with isostatic pressing process are significantly improved compared with the density and thermal conductivity of the alumina ceramic substrate without isostatic pressing process, and the sintering aid has a great influence on the thermal conductivity of the alumina ceramic substrate. The sintering aid can promote the densification of alumina ceramics and purify the impurities in the alumina ceramic lattice to enrich the triple grain boundaries.

[0048] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module, characterized in that: include: S1, adding a dispersant, alumina powder, and a sintering aid into a solvent and mixing them evenly to obtain a primary slurry, and then performing a primary ball milling on the primary slurry, wherein the weight ratio of the dispersant, alumina powder, sintering aid, and solvent is 3:95:5:40; S2, adding a binder and a plasticizer to the primary slurry for secondary ball milling to obtain an alumina tape casting slurry, wherein the weight ratio of the primary slurry, the binder, and the plasticizer is 286:20:3; S3, degassing the alumina tape casting slurry; S4, tape-casting the alumina tape-casting slurry after degassing on a tape-casting machine, and drying to obtain a tape-casting green body; S5, subjecting the tape-cast green body to isostatic pressing in a warm isostatic press; S6, sequentially performing binder removal, sintering, grinding and polishing on the tape-cast green body after isostatic pressing to obtain an alumina ceramic substrate.

2. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 1, characterized in that: The solvent is one or more of ethanol, isopropanol, methyl ethyl ketone, trichloroethylene, benzene, toluene, and xylene; The dispersant is one or more of oleic acid, triethyl phosphate, and castor oil; The binder is polyvinyl butyral; The plasticizer is one or more of dibutyl phthalate, polyethylene glycol, and dioctyl phthalate; The sintering aid is one or more of Y2O3, MgO, SiO2, ZrO2, and CaO; The alumina powder has a particle size of 0.8 microns to 1.5 microns and a purity of ≥ 99.9%; The isostatic pressing treatment has a pressure of 50Mpa-80Mpa and a temperature of 60°C-80°C; The debinding temperature is 500°C-700°C, the debinding rate is 1°C / min, and the sintering temperature is 1550-1650°C.

3. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 1, characterized in that: The tape-cast green body is transported from the tape-casting machine to the warm isostatic press by a flatbed trolley. A bearing plate is detachably and horizontally fixedly mounted on the flatbed trolley. The bearing plate can slide horizontally on the flatbed trolley. A plurality of tape-cast green bodies are placed on the bearing plate.

4. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 3, characterized in that: The tape casting machine has a conveyor belt, and the tape casting green body is conveyed to the supporting plate by the conveyor belt.

5. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 4, characterized in that: The warm isostatic press comprises: The hot isostatic pressure box has a support leg, a rotating shaft and a brake motor at its lower end, the rotating shaft is fixedly connected to a mounting seat, the mounting seat is provided with a guide plate, a push-pull device, a rotating motor and a shaft sleeve, the guide plate, the push-pull device are fixedly connected to the mounting seat, the rotating motor is slidably connected to the mounting seat, the shaft sleeve is transmission-connected to the rotating motor, and the shaft sleeve is driven to rotate by the rotating motor, the push-pull device is connected to the rotating motor, and is used to drive the rotating motor to slide on the mounting seat, the brake motor is transmission-connected to the rotating shaft, and is used to drive the mounting seat to rotate around the rotating shaft, a box door is provided on the side of the hot isostatic pressure box, when the brake motor drives the mounting seat to rotate to the lower end of the hot isostatic pressure box, the box door can be opened, when the brake motor drives the mounting seat to rotate to the door of the hot isostatic pressure box, the guide plate is horizontal, and the upper surface of the guide plate is flush with the lower surface of the bearing plate on the flatbed trolley, and the bearing plate on the flatbed trolley can slide horizontally onto the guide plate; The lifting mechanism is arranged in the warm isostatic pressing box. A plurality of slides are arranged on the lifting mechanism. The plurality of slides are lifted and lowered under the drive of the lifting mechanism. When a certain slide is lifted and lowered to be flush with the horizontal guide plate, the bearing plate on the guide plate can slide horizontally onto the slide.

6. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 5, characterized in that: There is a pair of lifting mechanisms, which are symmetrically arranged on the two side walls of the warm isostatic pressure box, and the bearing plate is located between the pair of lifting mechanisms; The lifting mechanism comprises: A plurality of installation cylinders are arranged at intervals, the plurality of installation cylinders are coaxial, and the plurality of installation cylinders are fixedly connected by a connecting plate, the connecting plate is located in the installation cylinder, a slideway is defined between two adjacent installation cylinders, a plurality of sliders are slidably installed in the slideway along the circumference of the installation cylinder, and each slider is fixedly connected to a slide seat; The baffle is fixedly connected to the mounting cylinder and the warm isostatic pressure box; The second rotating shaft is located in the installation cylinder and is rotatably connected to the baffle. A sprocket is arranged on the second rotating shaft. There are at least two second rotating shafts, which are arranged at the upper and lower ends of the installation cylinder. A chain is wound around the sprocket, and the chain is fixedly connected to the slider. The shaft block is coaxially fixedly installed at one end of the second rotating shaft close to the door. When the guide plate is horizontal, the push-pull device pushes the shaft sleeve to move and can be connected with the shaft block through plug-in transmission; The lifting limit device is vertically fixed on the inner bottom surface of the warm isostatic pressure box and is located directly below the slide seats at both ends of the bearing plate. The lifting limit device can lift and fix the slide seat at the lower end.

7. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 6, characterized in that: S5, the process of isostatically pressing the tape-cast green body in a warm isostatic press comprises: S51, controlling the conveyor belt of the tape casting machine to rotate and horizontally transfer the dried tape casting green body to a carrying plate on the flat cart; S52, after the carrying plate on the flatbed cart is fully loaded with the tape-cast green body, the flatbed cart is moved close to the warm isostatic press; S53, opening the box door, controlling the brake motor to drive the mounting seat to rotate around the rotating shaft until the guide plate is horizontal, and the mounting seat is located at the door of the warm isostatic pressure box; S54, control the push-pull device to push the shaft sleeve to move and connect with the shaft block plug-in transmission, start the rotating motor to drive the rotating shaft 2 to rotate and adjust the position of the slide seat until the front end slide seat in the chain rotation direction is flush with the guide plate; S55, pushing the load-bearing plate to slide horizontally from the flatbed cart, and the load-bearing plate slides into the slide seat through the guide plate; S56, controlling the rotary motor to drive the second rotating shaft to rotate so that the next slide is flush with the guide plate, and then pushing the load plate on the next flatbed cart to slide horizontally, and the load plate slides into the slide through the guide plate; S57, repeat S56 until all slides have bearing plates, then control the push-pull device to drive the shaft sleeve and shaft block to separate and reset, then control the brake motor to drive the mounting seat to rotate and reset, and finally close the box door to perform isostatic pressing.

8. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 7, characterized in that: Before the push-pull device is controlled in S57 to drive the shaft sleeve to separate from the shaft block, the lifting limit device is first controlled to lift and fix the sliding seat at the lower end.

9. The method for preparing a high thermal conductivity alumina ceramic substrate for a fast response IGBT module according to claim 8, characterized in that: After the medium static pressure treatment in S57 is completed, S53 is performed first, and then the push-pull device is controlled to push the shaft sleeve to move and connect with the shaft block plug-in transmission, and then the jacking limit device is controlled to descend and reset, and then the rotating motor is started to drive the rotating shaft 2 to rotate and adjust the position of the slide, so that the slide and the guide plate are flush at the same height, and finally the load-bearing plate on the slide is pulled out horizontally.

10. A high thermal conductivity alumina ceramic substrate for a fast-response IGBT module, characterized in that: The invention is prepared by the method for preparing a high thermal conductivity alumina ceramic substrate for a fast-response IGBT module according to any one of claims 1 to 9.

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