High thermal conductive alumina ceramic substrate for fast response IGBT module and preparation method thereof

Abstract

The application discloses a kind of high heat-conducting alumina ceramic substrate for fast response IGBT module and preparation method thereof, and relates to the technical field of ceramic materials, wherein the preparation method of the high heat-conducting alumina ceramic substrate for fast response IGBT module includes: S1, dispersing agent, alumina powder, sintering aid are added into solvent and mixed to obtain primary slurry, then the primary slurry is first ball milled, and the weight ratio of dispersing agent, alumina powder, sintering aid and solvent is 3:95:5:40; S2, add binder and plasticizer to the primary slurry for secondary ball milling to obtain alumina casting forming slurry, and the weight ratio of primary slurry, binder and plasticizer is 286:20:3. Advantage: the alumina ceramic substrate prepared by the technical solution of the present application has the advantage of high heat conduction efficiency, thereby greatly improving the heat dissipation efficiency and response speed of the IGBT module, effectively meeting the application demand of high-performance IGBT module in the market.

Description

TECHNICAL FIELD

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

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

[0003] The main purpose of the application is to provide a high-thermal-conductivity alumina ceramic substrate for an IGBT module with fast response and a preparation method thereof, aiming at solving the problem of low heat conduction efficiency of the existing alumina ceramic substrate, which affects the heat dissipation efficiency and response speed of the IGBT module.

[0004] To solve the above problems, the application provides a preparation method of a high-thermal-conductivity alumina ceramic substrate for an IGBT module with fast response, which comprises the following steps:

[0005] S1, a dispersing agent, alumina powder and a sintering aid are added to a solvent to obtain a primary slurry, and then the primary slurry is subjected to primary ball milling, and the weight ratio of the dispersing agent, the alumina powder, the sintering aid and the solvent is 3:95:5:40;

[0006] S2, a binder and a plasticizer are added to the primary slurry to perform secondary ball milling, so as to obtain an alumina tape casting slurry, and the weight ratio of the primary slurry, the binder and the plasticizer is 286:20:3;

[0007] S3, the alumina tape casting slurry is subjected to defoaming treatment;

[0008] S4, the alumina tape casting slurry after the defoaming treatment is subjected to tape casting and drying on a tape casting machine to obtain a tape casting green body;

[0009] S5, the tape casting green body is subjected to isostatic pressing in an isostatic pressing machine;

[0010] S6, the tape casting green body after the isostatic pressing is sequentially subjected to degassing, sintering, grinding and polishing to obtain the alumina ceramic substrate.

[0011] In an embodiment, the solvent is one or more of ethanol, isopropyl alcohol, methyl ethyl ketone, trichloroethylene, benzene, toluene and xylene.

[0012] The dispersant is one or more of oleic acid, triethyl phosphate, castor oil;

[0013] The binder is polyvinyl butyral;

[0014] The plasticizer is one or more of dibutyl phthalate, polyethylene glycol, dioctyl phthalate;

[0015] The sintering aid is one or more of Y2O3, MgO, SiO2, ZrO2, CaO;

[0016] The alumina powder has a particle size of 0.8-1.5 microns and a purity of ≥99.9%;

[0017] The isostatic pressing process has a pressure of 50-80 MPa and a temperature of 60-80°C;

[0018] The degassing temperature is 500-700°C, the degassing rate is 1°C / min, and the sintering temperature is 1550-1650°C.

[0019] In an embodiment, the green body is transported from the casting forming machine to the warm isostatic press by a flat trolley, a load-bearing plate is detachably and horizontally fixedly installed on the flat trolley, the load-bearing plate can slide horizontally on the flat trolley, and a plurality of green bodies are placed on the load-bearing plate.

[0020] In an embodiment, the casting forming machine has a conveying belt, and the green body is conveyed onto the load-bearing plate by the conveying belt.

[0021] In an embodiment, the warm isostatic press comprises:

[0022] The warm isostatic press box is provided with a support leg, a rotating shaft one and a brake motor at the lower end, the rotating shaft one is fixedly connected with a mounting seat, a guide plate, a push-pull device, a rotating motor and a shaft sleeve are arranged on the mounting seat, the guide plate and the push-pull device are fixedly connected with the mounting seat, the rotating motor is slidingly connected with the mounting seat, the shaft sleeve is drivingly connected with the rotating motor, the shaft sleeve is driven to rotate by the rotating motor, the push-pull device is connected with the rotating motor to drive the rotating motor to slide on the mounting seat, the brake motor is drivingly connected with the rotating shaft one to drive the mounting seat to rotate around the rotating shaft one, a door is arranged on the side of the warm isostatic press box, when the brake motor drives the mounting seat to rotate to the lower end of the warm isostatic press box, the door can be opened, when the brake motor drives the mounting seat to rotate to the door opening of the warm isostatic press box, the guide plate is horizontal, and the upper surface of the guide plate is flush with the lower surface of the load-bearing plate on the flat trolley, and the load-bearing plate on the flat trolley can slide horizontally onto the guide plate;

[0023] The lifting mechanism is arranged in the warm isostatic pressing box, a plurality of sliding seats are arranged on the lifting mechanism, and the plurality of sliding seats are lifted under the driving of the lifting mechanism. When a sliding seat is lifted to the same height as the horizontal guide plate, the load-bearing plate on the guide plate can be horizontally slid onto the sliding seat.

[0024] In an embodiment, the lifting mechanism has a pair and is symmetrically arranged on the two side walls in the warm isostatic pressing box, and the load-bearing plate is located between the pair of lifting mechanisms.

[0025] The lifting mechanism comprises:

[0026] A plurality of installation barrels are arranged at intervals, the plurality of installation barrels are coaxial, the plurality of installation barrels are fixedly connected through a connecting plate, the connecting plate is located in the installation barrel, a sliding channel is defined between adjacent two installation barrels, a plurality of sliding blocks are slidably arranged in the sliding channel along the circumferential direction of the installation barrel, and each sliding block is fixedly connected with a sliding seat.

[0027] A baffle is fixedly connected with the installation barrel and the warm isostatic pressing box.

[0028] A second rotating shaft is located in the installation barrel and is rotatably connected with the baffle, a chain wheel is arranged on the second rotating shaft, the second rotating shaft has at least two, and the two are arranged at the upper and lower ends of the installation barrel, a chain is wound on the chain wheel, and the chain is fixedly connected with the sliding block.

[0029] A shaft block is coaxially and fixedly arranged at one end of the second rotating shaft close to the door, when the guide plate is horizontal, the push-pull device drives the shaft sleeve to move and is connected with the shaft block through insertion transmission.

[0030] A jacking limiting device is vertically fixed on the bottom surface in the warm isostatic pressing box and located directly below the sliding seat at the two ends of the load-bearing plate, and the jacking limiting device can jackingly fix the lowermost sliding seat.

[0031] In an embodiment, S5, the isostatic pressing treatment of the flow molding green body in the warm isostatic pressing machine comprises:

[0032] S51, the control of the conveying belt of the flow forming machine moves the dry flow molding green body horizontally to the load-bearing plate on the flat plate cart;

[0033] S52, after the load-bearing plate on the flat plate cart is loaded with flow molding green bodies, the flat plate cart is moved close to the warm isostatic pressing machine;

[0034] S53, open the door, control the brake motor to drive the mounting seat to rotate around the first rotating shaft until the guide plate is horizontal, at this time the mounting seat is located in the door of the warm isostatic pressing box;

[0035] S54, control the push-pull device to drive the shaft sleeve to move and be connected with the shaft block through insertion transmission, start the rotating motor to drive the second rotating shaft to rotate to adjust the position of the sliding seat, until the sliding seat at the forefront in the rotating direction of the chain is leveled with the guide plate.

[0036] S55, push the bearing plate from the flat cart to start horizontal sliding, the bearing plate slides into the slide through the guide plate;

[0037] S56, control the rotating motor to drive the second rotating shaft to rotate to make the next slide equal to the guide plate, then push the bearing plate on the next flat cart to slide horizontally, and the bearing plate slides into the slide through the guide plate;

[0038] S57, repeat S56 until all slides have bearing plates, then control the push-pull device to drive the shaft sleeve and the 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 for isostatic pressing.

[0039] In an embodiment, before the control of the push-pull device drives the shaft sleeve and the shaft block to separate in S57, the jacking limiting device is controlled to jacking the fixed lowest slide.

[0040] In an embodiment, after the isostatic pressing is completed in S57, S53 is performed first, then the push-pull device is controlled to move the shaft sleeve and the shaft block to connect the transmission, then the jacking limiting device is controlled to descend and reset, the rotating motor is started to drive the second rotating shaft to rotate to adjust the position of the slide, the slide is made equal to the guide plate, and finally the bearing plate on the slide is pulled out horizontally.

[0041] In addition, the application also provides a high-thermal-conductivity alumina ceramic substrate for IGBT module with fast response, which is prepared by the preparation method of the high-thermal-conductivity alumina ceramic substrate for IGBT module with fast response.

[0042] Beneficial effects: the alumina ceramic substrate prepared by the technical solution of the application has the advantage of high heat conduction efficiency, so that the heat dissipation efficiency and response speed of the IGBT module are greatly improved, effectively meeting the application demand of the market for high-performance IGBT modules. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0044] Figure 1 is the SEM surface graph of the alumina ceramic substrate prepared in embodiment one;

[0045] Figure 2 is the SEM cross-sectional graph of the alumina ceramic substrate prepared in embodiment one;

[0046] Figure 3 is a structural schematic view of the flat trolley and warm isostatic presser of the present application;

[0047] Figure 4 is an enlarged view of A part in Figure 3 ;

[0048] Figure 5 is a D-D sectional view in Figure 3 ;

[0049] Figure 6 is an enlarged view of B part in Figure 5 ;

[0050] Figure 7 is a front view of the warm isostatic presser box;

[0051] Figure 8 is a structural schematic view of the lifting mechanism;

[0052] Figure 9 is an E-E sectional view in Figure 8 ;

[0053] Figure 10 is an enlarged view of C part in Figure 9 .

[0054] The reference signs are explained as follows:

[0055] 1, casting machine; 2, casting green body; 3, conveying belt; 4, flat trolley; 5, bearing plate; 6, locking screw; 7, warm isostatic presser box; 8, supporting leg; 9, box door; 10, brake motor; 11, mounting seat; 12, rotating shaft 1; 13, push-pull device; 14, rotating motor; 15, shaft sleeve; 16, guide plate; 17, baffle; 18, mounting cylinder; 19, slide; 20, connecting plate; 21, rotating shaft 2; 22, chain wheel; 23, shaft block; 24, chain; 25, sliding block; 26, sliding seat; 27, groove; 28, connecting block; 29, jacking limiting device. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0057] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, motion condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0058] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be internal connection of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] In addition, if the embodiments of the present application involve "first", "second" and the like, the "first", "second" and the like are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions, for example, "A and / or B" includes A solution, or B solution, or A and B solution. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection claimed by the present application.

[0060] The present application provides a preparation method of a high-thermal-conductivity alumina ceramic substrate for IGBT module with fast response, which 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, so as to greatly improve the heat dissipation efficiency and response speed of the IGBT module, and effectively meet the application demand of the market for high-performance IGBT module.

[0061] Specifically, in one embodiment of the present application, the preparation method of the high-thermal-conductivity alumina ceramic substrate for IGBT module with fast response comprises:

[0062] S1, the dispersant, alumina powder, sintering aid is added to the solvent and mixed to obtain a primary slurry, then the primary slurry is subjected to primary ball milling, the weight ratio of dispersant, alumina powder, sintering aid, solvent is 3:95:5:40, the ball milling time is determined according to the total amount of the primary slurry, and the ball milling is stopped as long as the particle size meets the specified requirements;

[0063] S2, the primary slurry is added with a binder and a plasticizer for secondary ball milling to obtain an alumina tape casting slurry, the weight ratio of the primary slurry, the binder and the plasticizer is 286:20:3, the ball milling time is determined according to the total amount of the primary slurry, and the ball milling is stopped as long as the particle size meets the specified requirements;

[0064] S3, the alumina tape casting slurry is subjected to defoaming treatment;

[0065] S4, the alumina tape casting slurry after defoaming treatment is subjected to tape casting and drying on a tape casting machine 1 to obtain a tape green body 2;

[0066] S5, the tape green body 2 is subjected to isostatic pressing treatment in an isostatic pressing machine to eliminate defects and bubbles in the tape green body 2 and improve the density of the tape green body 2, thereby improving the heat conduction efficiency of the alumina ceramic substrate and greatly improving the heat dissipation efficiency and response speed of the IGBT module, effectively meeting the application demand of the market for high-performance IGBT modules;

[0067] S6, the tape green body 2 after isostatic pressing treatment is sequentially subjected to glue removal, sintering, grinding and polishing to obtain an alumina ceramic substrate.

[0068] In the embodiment, the solvent is one or more of ethanol, isopropyl alcohol, methyl ethyl ketone, trichloroethylene, benzene, toluene and xylene;

[0069] The dispersant is one or more of oleic acid, triethyl phosphate and castor oil;

[0070] The binder is polyvinyl butyral;

[0071] The plasticizer is one or more of dibutyl phthalate, polyethylene glycol and dioctyl phthalate;

[0072] The sintering aid is one or more of Y2O3, MgO, SiO2, ZrO2 and CaO;

[0073] The particle size of the alumina powder is 0.8-1.5 microns, and the purity is ≥99.9%;

[0074] The pressure of the isostatic pressing treatment is 50-80 MPa, and the temperature is 60-80℃;

[0075] The temperature of the glue removal is 500-700 DEG C, the glue removal rate is 1 DEG C / min, and the sintering temperature is 1550-1650 DEG C.

[0076] The preparation method of the high-thermal-conductivity alumina ceramic substrate for a fast-response IGBT module in the embodiment selects a cation mineralizer as a sintering aid, and uses low-temperature rapid sintering technology and isostatic pressing technology to promote the rapid densification of the alumina ceramic substrate and improve the heat conduction efficiency. The thermal conductivity of the alumina ceramic substrate can reach more than 30 W / mK, achieving excellent heat dissipation efficiency and response speed. Subsequent grinding and polishing processing further eliminates surface defects of the alumina ceramic substrate and improves the heat transfer efficiency. The alumina ceramic substrate can rapidly transfer heat in a high-frequency switching state, maintain the temperature stability of the IGBT module, and maintain excellent electrical insulation and mechanical strength, fully meeting the needs of modern power electronic devices for efficient heat dissipation and fast response.

[0077] In addition, in order to improve the production efficiency of the alumina ceramic substrate, the cast green body 2 in S4 and S5 can be transported from the casting forming machine 1 to the warm isostatic pressing machine by the flat trolley 4, and the flat trolley 4 is detachably and horizontally fixedly installed with a bearing plate 5, such as Figure 3 and Figure 4 The bearing plate 5 is detachably and horizontally fixedly connected with the flat trolley 4 by a locking screw 6, the bearing plate 5 can slide horizontally on the flat trolley 4, and a plurality of cast green bodies 2 are placed on the bearing plate 5. The casting forming machine 1 has a conveying belt 3, and the dry cast green body 2 is conveyed to the bearing plate 5 by the conveying belt 3.

[0078] In the embodiment, as shown in Figures 3-10 The warm isostatic pressing machine includes a warm isostatic pressing box 7 and a lifting mechanism. The lower end of the warm isostatic pressing box 7 is provided with a supporting leg 8, a rotating shaft one 12, and a brake motor 10. The supporting leg 8 is used to support and fix the warm isostatic pressing box 7. The brake motor 10 is fixedly connected with the warm isostatic pressing box 7. The rotating shaft one 12 is rotationally connected with the warm isostatic pressing box 7. The rotating shaft one 12 is fixedly connected with a mounting seat 11, as shown in Figure 3 and Figure 5 The mounting seat 11 is provided with a guide plate 16, a push-pull device 13, a rotating motor 14, and a shaft sleeve 15. The guide plate 16 and the push-pull device 13 are fixedly connected with the mounting seat 11. The rotating motor 14 is slidingly connected with the mounting seat 11. The shaft sleeve 15 is drivingly connected with the rotating motor 14. The shaft sleeve 15 is driven to rotate by the rotating motor 14. The push-pull device 13 is connected with the rotating motor 14 and is used to drive the rotating motor 14 to slide on the mounting seat 11. The brake motor 10 is drivingly connected with the rotating shaft one 12 and is used to drive the mounting seat 11 to rotate between the solid line position and the dashed line position of the rotating shaft one 12. Figure 3 ​

[0079] In the embodiment, as shown in Figure 3 and Figure 5 , the side of the warm isostatic pressing box 7 is provided with a box door 9, only when the brake motor 10 drives the mounting seat 11 to rotate to the lower end of the warm isostatic pressing box 7, the box door 9 can be opened, as shown in Figure 3 and Figure 5 , the brake motor 10 drives the mounting seat 11 to rotate to the door of the warm isostatic pressing box 7, the guide plate 16 is horizontal, and the upper surface of the guide plate 16 is level with the lower surface of the bearing plate 5 on the flat cart 4. In this way, the bearing plate 5 on the flat cart 4 can be horizontally slid onto the guide plate 16.

[0080] In the embodiment, the lifting mechanism is arranged in the warm isostatic pressing box 7, and a plurality of sliding seats 26 are arranged on the lifting mechanism. The plurality of sliding seats 26 are driven by the lifting mechanism to ascend and descend. When a certain sliding seat 26 ascends and descends to be level with the horizontal guide plate 16, the bearing plate 5 on the guide plate 16 can be horizontally slid onto the sliding seat 26. Then, the lifting mechanism drives the next sliding seat 26 to ascend and descend to be level with the horizontal guide plate 16. The foregoing operation is repeated to quickly load a plurality of bearing plates 5 into the warm isostatic pressing box 7. Each bearing plate 5 has a plurality of cast green bodies 2 placed thereon. Therefore, a large number of cast green bodies 2 can be quickly and efficiently loaded into the warm isostatic pressing box 7. Compared with the existing method of manually loading the cast green bodies 2 into the warm isostatic pressing box 7 by using both hands, the loading time of the warm isostatic pressing box 7 is greatly shortened, and the production efficiency of the aluminum oxide ceramic substrate is improved.

[0081] In the embodiment, the lifting mechanism has a pair and is symmetrically arranged on the two side walls in the warm isostatic pressing box 7. The bearing plate 5 is located between the pair of lifting mechanisms, as shown in Figures 5-10 , the lifting mechanism includes a baffle 17, a second rotating shaft 21, a shaft block 23, a jacking limiting device 29, a plurality of mounting cylinders 18 arranged at intervals, a plurality of mounting cylinders 18 are coaxial, a plurality of mounting cylinders 18 are fixedly connected through a connecting plate 20, the connecting plate 20 is located in the mounting cylinder 18, and a slide 19 is defined between adjacent two mounting cylinders 18. A plurality of sliding blocks 25 are slidably mounted in the slide 19 along the circumferential direction of the mounting cylinder 18. Each sliding block 25 is fixedly connected with a sliding seat 26, as shown in Figure 7 and Figure 8 , a plurality of bearing plates 5 are placed between the pair of lifting mechanisms from top to bottom. The lower surface of each bearing plate 5 is supported by a sliding seat 26 at both ends. A plurality of sliding blocks 25 fixedly connected with the sliding seat 26 are arranged at the same height, as shown in Figure 5 , Figure 6 , Figure 9 and Figure 10As shown, the slide 19 has multiple, so the slider 25 is in the same height position has multiple, the multiple slider 25 can be fixedly connected with a slide 26, the design, the length of the slide 26 can be designed longer, it is beneficial to expand the length of the bearing plate 5, so that more flow green body 2 is placed on a single bearing plate 5, further improve the production efficiency of the aluminum oxide ceramic substrate.

[0082] In this embodiment, as shown in Figures 5-10 The baffle 17 is fixedly connected with the mounting cylinder 18 and the warm isostatic pressing box 7, and the mounting cylinder 18 is supported and fixed by the baffle 17; the second rotating shaft 21 is located in the mounting cylinder 18 and is rotatably connected with the baffle 17, the second rotating shaft 21 is provided with a sprocket 22, and the second rotating shaft 21 has at least two and is arranged at the upper and lower ends of the mounting cylinder 18; the chain 24 is wound on the sprocket 22, and the chain 24 is fixedly connected with the sliding block 25; the second rotating shaft 21 rotates to drive the chain 24 to rotate through the sprocket 22, and then drives the sliding block 25 and the slide 26 to slide along the circumference of the mounting cylinder 18 around the slide 19, and the sliding track is a runway circle. Since the slide 26 slides around the outer wall of the mounting cylinder 18, the mounting cylinder 18 and the inner wall of the warm isostatic pressing 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 with the inner wall of the warm isostatic pressing box 7 through the connecting block 28.

[0083] In this embodiment, in order to avoid the connecting plate 20 interfering with the rotation of the chain 24, as shown in Figure 10 The connecting plate 20 is provided with a groove 27 for the chain 24 to pass through.

[0084] In this embodiment, as shown in Figure 5 The shaft block 23 is coaxially fixedly installed at one end of the second rotating shaft 21 close to the door, and when the guide plate 16 is horizontal, the shaft sleeve 15 can be connected with the shaft block 23 through plug-in transmission driven by the push-pull device 13, so as to drive the second rotating shaft 21 to rotate through the rotating motor 14.

[0085] In this embodiment, as shown in Figure 7 The jacking limiting device 29 is vertically fixed on the inner bottom surface of the warm isostatic pressing box 7 and is located directly below the slide 26 at both ends of the bearing plate 5. In this way, the jacking limiting device 29 can jackingly fix the lowermost slide 26, preventing the bearing plate 5 from pressing the slide 26 after the shaft sleeve 15 and the shaft block 23 are separated, causing the sprocket 22 and the second rotating shaft 21 to misrotate.

[0086] In this embodiment, S5, the flow green body 2 is subjected to isostatic pressing treatment in the warm isostatic pressing machine, which comprises:

[0087] S51, control the conveying belt 3 of the flow forming machine 1 to rotate to horizontally move the dried flow green body 2 to the bearing plate 5 on the flat cart 4;

[0088] S52. After the support plate 5 on the flatbed trolley 4 is full of the cast green blank 2, move the flatbed trolley 4 close to the isostatic press, and then move the next flatbed trolley 4 close to the conveyor belt 3 of the casting machine 1 to continue to move the dried cast green blank 2 onto the support plate 5 on the flatbed trolley 4. Therefore, multiple flatbed trolleys 4 are required.

[0089] S53. Open the chamber door 9 and control the brake motor 10 to drive the mounting base 11 to rotate around the rotating shaft 12 until the guide plate 16 is horizontal. At this time, the mounting base 11 is located at the door of the isostatic pressure chamber 7.

[0090] S54, the control push-pull device 13 pushes the bushing 15 to move and connects it with the shaft block 23 for transmission. The rotary motor 14 is started to drive the rotating shaft 21 to rotate, adjusting the position of the slide block 26 until the foremost slide block 26 in the direction of chain 24 rotation is level with the guide plate 16. The chain 24 rotates in the following direction: Figure 8 As shown;

[0091] S55, push the support plate 5 to slide horizontally from the flatbed trolley 4, and slide the support plate 5 into the slide block 26 through the guide plate 16;

[0092] S56, Control the rotary motor 14 to drive the rotating shaft 21. Figure 8 The chain 24 rotates in the direction shown so that the next slide 26 is level with the guide plate 16, and then pushes the carrier plate 5 on the next flatbed trolley 4 to slide horizontally. The carrier plate 5 slides into the slide 26 through the guide plate 16.

[0093] S57, Repeat S56 until all slides 26 have a bearing plate 5, such as Figure 7 As shown, at this time, the isostatic pressing chamber 7 is filled with the bearing plate 5. Then, the push-pull device 13 is controlled to drive the bushing 15 to separate and reset from the shaft block 23. Then, the brake motor 10 is controlled to drive the mounting base 11 to rotate and reset to its original position. Figure 3 At the position indicated by the dotted line, the chamber door 9 is finally closed for isostatic pressing. Compared with the existing method of manually loading the cast green blank 2 into the isostatic pressing chamber 7, this method of loading the cast green blank 2 into the isostatic pressing chamber 7 greatly shortens the loading time of the isostatic pressing chamber 7 and improves the production efficiency of alumina ceramic substrates.

[0094] In this embodiment, before the push-pull device 13 in S57 drives the bushing 15 to separate from the shaft block 23, the lifting limit device 29 is first controlled to lift and fix the lowest slide block 26, so as to prevent the bearing plate 5 from pressing down on the slide block 26 after the bushing 15 separates from the shaft block 23, causing the sprocket 22 and the rotating shaft 21 to rotate erroneously and cause a dangerous accident.

[0095] In the embodiment, after the hydrostatic pressure treatment in S57 is completed, S53 is first performed, then the push-pull device 13 is controlled to push the shaft sleeve 15 to move and be connected with the shaft block 23 for transmission, then the jacking limiting device 29 is controlled to descend and reset, and then the rotating motor 14 is started to drive the rotating shaft two 21 to rotate to adjust the position of the sliding seat 26, so that each sliding seat 26 is in turn leveled with the guide plate 16. When the sliding seat 26 is leveled with the guide plate 16, the load-bearing plate 5 on the sliding seat 26 can be horizontally pulled out onto the flat plate cart 4. This discharging mode is efficient, fast, simple and convenient, and further improves the production efficiency of the aluminum oxide ceramic substrate.

[0096] In addition, the application further provides a high-thermal-conductivity aluminum oxide ceramic substrate for an IGBT module with fast response, which is prepared by using the preparation method of the high-thermal-conductivity aluminum oxide ceramic substrate for an IGBT module with fast response.

[0097] The preparation method of the high-thermal-conductivity aluminum oxide ceramic substrate for an IGBT module with fast response will be described in detail below through multiple embodiments and comparative examples. Embodiment one:

[0098] In the embodiment, the preparation method of the high-thermal-conductivity aluminum oxide ceramic substrate for an IGBT module with fast response comprises:

[0099] S1, the dispersing agent, the aluminum oxide powder, and the sintering aid are added into the solvent to be uniformly mixed to obtain a primary slurry, the solvent is a mixture of ethanol, isopropyl alcohol, and dimethylbenzene, the mass ratio of the ethanol, the isopropyl alcohol, and the dimethylbenzene is 5:4:1, the total weight of the solvent is 80g, the dispersing agent is triethyl phosphate with a mass of 6g, the mass of the aluminum oxide powder is 190g, and the sintering aid is a mixture of 4g of Y2O3 and 6g of MgO, then the primary slurry is subjected to primary ball milling, the weight ratio of the dispersing agent, the aluminum oxide powder, the sintering aid, and the solvent is 3:95:5:40, and the ball milling time is 24h;

[0100] S2, the binder and the plasticizer are added into the primary slurry to be subjected to secondary ball milling, the binder is polyvinyl butylal with a mass of 20g, the plasticizer is dibutyl phthalate with a mass of 3g, the ball milling time is 24h, and the aluminum oxide tape casting slurry is obtained, the weight ratio of the primary slurry, the binder, and the plasticizer is 286:20:3;

[0101] S3, the aluminum oxide tape casting slurry is subjected to defoaming treatment;

[0102] S4, the aluminum oxide tape casting slurry after the defoaming treatment is subjected to tape casting and drying on the tape casting machine 1 to obtain a tape casting green body 2;

[0103] S5, the flow cast green body 2 is subjected to isostatic pressing treatment in a warm isostatic pressing machine, the isostatic pressing treatment temperature and pressure are 60℃ and 60Mpa respectively, defects and bubbles in the flow cast green body 2 are eliminated, and the density of the flow cast green body 2 is improved, so that the heat conduction efficiency of the aluminum oxide ceramic substrate is improved, the heat dissipation efficiency and response speed of the IGBT module are greatly improved, and the application demand of the market for high-performance IGBT modules is effectively met;

[0104] S6, the flow cast green body 2 subjected to isostatic pressing treatment is sequentially subjected to glue removal, sintering, grinding and polishing to obtain an aluminum oxide ceramic substrate, the glue removal temperature is 600℃, the glue removal rate is 1℃ / min, and the sintering temperature is 1550℃. After sintering, it needs to be kept for 2 hours.

[0105] In the embodiment, the particle size of the aluminum oxide powder is 0.8-1.5 microns, and the purity is ≥99.9%; Example two:

[0106] The difference between example two and example one is only that:

[0107] The sintering aid is 2g Y2O3, 4g CaO and 4g MgO;

[0108] The isostatic pressing treatment temperature is 70℃;

[0109] The sintering temperature is 1570℃. Example three:

[0110] The difference between example three and example one is only that:

[0111] The sintering aid is 2g Y2O3, 2g CaO, 2g SiO2 and 4g MgO;

[0112] The isostatic pressing treatment temperature and pressure are 80℃ and 80Mpa respectively;

[0113] The sintering temperature is 1600℃.

[0114] Comparative example one:

[0115] The difference between comparative example one and example one is only that:

[0116] There is no sintering aid;

[0117] The sintering temperature is 1650℃.

[0118] Comparative example two:

[0119] The difference between comparative example two and example one is only that: no isostatic pressing treatment.

[0120] The performance test results of the aluminum oxide ceramic substrates prepared in the foregoing example one, example two, example three, comparative example one and comparative example two are as follows:

[0121]

[0122] From the above table, it can be seen 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 the alumina ceramic and purify the impurities in the alumina ceramic lattice, so as to enrich the three-pronged grain boundaries.

[0123] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, using the content of the present application specification and drawings, or directly / indirectly applied in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for producing a high thermal conductive alumina ceramic substrate for a fast response IGBT module, characterized by, The application relates to a method for preparing an alumina ceramic substrate. S1, uniformly mixing dispersant, alumina powder and sintering aid in a solvent to obtain primary slurry, and then performing primary ball milling on the primary slurry, wherein the weight ratio of the dispersant, the alumina powder, the sintering aid and the solvent is 3:95:5:40; S2, adding a binder and a plasticizer into the primary slurry to perform secondary ball milling, so as to obtain alumina tape casting slurry, wherein the weight ratio of the primary slurry, the binder and the plasticizer is 286:20:3; S3, performing defoaming treatment on the alumina tape casting slurry; S4, performing tape casting and drying on the defoamed alumina tape casting slurry to obtain a green tape; S5, performing isostatic pressing on the green tape in a warm isostatic pressing machine; comprising: S51, controlling the conveying belt of the tape casting machine to horizontally move the dried green tape to the bearing plate on the flat trolley; S52, after the bearing plate on the flat trolley is full of the green tape, moving the flat trolley close to the warm isostatic pressing machine; S53, opening the box door, controlling the brake motor to drive the mounting seat to rotate around the rotating shaft one until the guide plate is horizontal, and at this time, the mounting seat is located at the door of the warm isostatic pressing box; S54, controlling the push-pull device to drive the shaft sleeve to move and be connected with the shaft block insertion transmission, starting the rotating motor to drive the rotating shaft two to rotate to adjust the position of the sliding seat, until the sliding seat at the most front end in the chain rotation direction is in level with the guide plate; S55, pushing the bearing plate to start horizontal sliding from the flat trolley, and the bearing plate slides into the sliding seat through the guide plate; S56, controlling the rotating motor to drive the rotating shaft two to rotate to make the next sliding seat in level with the guide plate, then pushing the bearing plate on the next flat trolley to horizontally slide, and the bearing plate slides into the sliding seat through the guide plate; S57, repeating S56 until all the sliding seats have the bearing plates, then controlling the push-pull device to drive the shaft sleeve to separate from the shaft block and reset, then controlling the brake motor to drive the mounting seat to rotate and reset, and finally closing the box door to perform isostatic pressing treatment; S6, sequentially performing glue removal, sintering, grinding and polishing on the green tape after isostatic pressing to obtain the alumina ceramic substrate; The green tape is conveyed from the tape casting machine to the warm isostatic pressing machine by the flat trolley, the bearing plate is detachably and horizontally fixedly installed on the flat trolley, the bearing plate can horizontally slide on the flat trolley, and a plurality of green tapes are placed on the bearing plate; The tape casting machine has a conveying belt, the green tape is conveyed to the bearing plate by the conveying belt; and the warm isostatic pressing machine comprises: The warm isostatic pressing box is provided with a supporting leg, a rotating shaft I and a brake motor at the lower end, the rotating shaft I is fixedly connected with a mounting seat, a guide plate, a push-pull device, a rotating motor and a shaft sleeve are arranged on the mounting seat, the guide plate and the push-pull device are fixedly connected with the mounting seat, the rotating motor is slidably connected with the mounting seat, the shaft sleeve is drivingly connected with the rotating motor, the shaft sleeve is driven to rotate by the rotating motor, the push-pull device is connected with the rotating motor and is used for driving the rotating motor to slide on the mounting seat, the brake motor is drivingly connected with the rotating shaft I and is used for driving the mounting seat to rotate around the rotating shaft I, a box door is arranged on the side of the warm isostatic pressing box, the box door can be opened when the mounting seat is driven by the brake motor to rotate to the lower end of the warm isostatic pressing box, the guide plate is horizontal when the mounting seat is driven by the brake motor to rotate to the door opening of the warm isostatic pressing box, the upper surface of the guide plate is flush with the lower surface of a bearing plate on a flat cart, and the bearing plate on the flat cart can slide horizontally to the guide plate; A lifting mechanism is arranged in the warm isostatic pressing box, a plurality of sliding seats are arranged on the lifting mechanism, the sliding seats are driven to rise and fall by the lifting mechanism, and the bearing plate on the guide plate can slide horizontally to the sliding seat when a certain sliding seat rises and falls to be flush with the horizontal guide plate; The lifting mechanism is provided in pairs and is symmetrically arranged on the two side walls in the warm isostatic pressing box, and the bearing plate is located between the pair of lifting mechanisms; The lifting mechanism comprises: A plurality of mounting cylinders are arranged at intervals, the mounting cylinders are coaxial, the mounting cylinders are fixedly connected through a connecting plate, the connecting plate is located in the mounting cylinder, a sliding channel is defined between adjacent two mounting cylinders, a plurality of sliding blocks are slidingly arranged in the sliding channel along the circumferential direction of the mounting cylinder, and each sliding block is fixedly connected with a sliding seat; A baffle is fixedly connected with the mounting cylinder and the warm isostatic pressing box; A rotating shaft II is located in the mounting cylinder and is rotatably connected with the baffle, chain wheels are arranged on the rotating shaft II, the rotating shaft II has at least two, and the two rotating shafts II are arranged at the upper and lower ends of the mounting cylinder, chains are wound on the chain wheels, and the chains are fixedly connected with the sliding blocks; A shaft block is coaxially fixedly arranged at one end of the rotating shaft II close to the door opening, and the push-pull device drives the shaft sleeve to move to be connected with the shaft block for transmission when the guide plate is horizontal; A jacking limiting device is vertically fixed on the bottom surface in the warm isostatic pressing box and is located directly below the sliding seats at the two ends of the bearing plate, and the jacking limiting device can jackingly fix the lowermost sliding seat; The solvent is one or more of ethanol, isopropyl alcohol, methyl ethyl ketone, trichloroethylene, benzene, toluene and xylene; The dispersing agent 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 particle size of the alumina powder is 0.8-1.5 microns, and the purity is greater than or equal to 99.9%; The pressure of the warm isostatic pressing treatment is 50-80 MPa, and the temperature is 60-80 DEG C. The temperature of the glue removal is 500-700 DEG C, the glue removal rate is 1 DEG C / min, and the sintering temperature is 1550-1650 DEG C.

2. The method of claim 1, wherein the high thermal conductivity alumina ceramic substrate for a fast response IGBT module is prepared by the steps of: preparing a green sheet by mixing and kneading alumina powder, a sintering aid, and a binder; and pressing the green sheet to a predetermined thickness. Before the separation of the shaft sleeve and the shaft block driven by the push-pull device in S57, the jacking limiting device is controlled to jacking the lowermost slide.

3. The method of claim 2, wherein the high thermal conductivity alumina ceramic substrate for a fast response IGBT module is prepared by the steps of: preparing a green sheet by mixing and kneading alumina powder, a sintering aid, and a binder; and pressing the green sheet to a predetermined thickness. After the isostatic pressing is completed in S57, S53 is performed, then the push-pull device is controlled to move the shaft sleeve to be connected with the shaft block through insertion transmission, then the jacking limiting device is controlled to descend and reset, then the rotating motor is started to drive the rotating shaft II to rotate to adjust the position of the slide, so that the slide is leveled with the guide plate, and finally the load plate on the slide is horizontally pulled out.

4. A high thermal conductive alumina ceramic substrate for a fast response IGBT module, characterized by, The high-thermal-conductivity alumina ceramic substrate for a fast-response IGBT module is prepared by the method of any one of claims 1 to 3.

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