An integrated ceramic heat sink structure based on tape casting method and its manufacturing method

Abstract

The present invention provides an integrated ceramic vapor chamber structure based on a tape casting method, comprising a vapor chamber, a support column and a working fluid: the vapor chamber comprises an upper plate body and a lower plate body, a chamber is arranged between the upper plate body and the lower plate body, a plurality of grooves are arranged on the bottom surface of the upper plate body and the top surface of the lower plate body, and the grooves on the upper plate body and the lower plate body are arranged side by side; micrometer or / and nanometer-level cavities are arranged on the surface of the support column, a plurality of support columns are arranged between the upper plate body and the lower plate body in the chamber, and the plurality of support columns are evenly distributed in the chamber; the working fluid is sealed in the chamber. The vapor chamber structure can solve the technical problems of poor heat-absorbing performance and inconvenient processing of existing ceramic vapor chambers.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic vapor chambers, and in particular to an integrated ceramic vapor chamber structure based on a tape casting method and a manufacturing method thereof. Background Art

[0002] With the rapid development of the third generation of semiconductors, power semiconductor devices are developing rapidly towards high power, miniaturization and multi-functions. However, as the system integration continues to increase, its power density also increases rapidly. The integration of system functions leads to uneven heat distribution. The original traditional packaging technology cannot meet the requirements of high temperature and high frequency characteristics of the third generation of semiconductors. Ceramic substrates, as semiconductor packaging substrates, are ideal components for balancing temperature and heat dissipation. Ceramic substrates can also provide attachment for electronic circuits, and the heat dissipation of electronic circuits can also be dissipated through ceramic substrates.

[0003] The vapor chamber is a highly efficient heat transfer technology that can fully utilize the extremely high heat transfer coefficient brought about by phase change and can quickly transfer the heat generated by the packaged device. It is an effective way to solve the heat dissipation problems of semiconductor packaging and electronic circuits. Most of the vapor chambers or heat pipes currently in production and research are made of metal materials, such as copper, stainless steel, aluminum, etc. Metal vapor chambers or heat pipes are conductive by themselves and cannot be directly used for semiconductor heat dissipation and circuit board heat dissipation, making it difficult to give full play to the heat dissipation advantages of the vapor chamber.

[0004] In traditional power semiconductor modules, most of the heat generated by chip power loss is diffused through the chip solder layer, ceramic liner, liner solder layer, substrate, TIM (Thermal Interface Material) to the heat sink. Ceramic heat spreader can directly replace ceramic liner, liner solder layer, substrate and optimize the packaging structure.

[0005] The existing ceramic heat spreader grooves are difficult to process and have simple shapes, which cannot meet the requirements of efficient reflux; there is no supporting structure in the middle, which cannot adapt to large and complex shape requirements; the structure is welded or bonded by the upper and lower plates, and cracks and leakages often occur, seriously affecting the performance of the equipment.

[0006] Therefore, how to provide an integrated heat-spreading substrate and a manufacturing method thereof that is easy to process, has a wide range of applications, has good heat-spreading performance, is non-conductive and has good thermal matching is of great significance for power semiconductor module packaging and electronic circuit packaging. Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide an integrated ceramic vapor chamber structure based on a tape casting method, which can solve the technical problems of poor thermal conductivity and inconvenient processing of existing ceramic vapor chambers.

[0008] The second technical problem solved by the present application is to provide a method for manufacturing an integrated ceramic heat sink structure based on a tape casting method.

[0009] In order to solve the first technical problem mentioned above, the technical solution of the present invention is: an integrated ceramic heat spreader structure based on the casting method, including a heat spreader, a support column and a working fluid, the heat spreader includes an upper plate body and a lower plate body, a chamber is provided between the upper plate body and the lower plate body, the bottom surface of the upper plate body and the top surface of the lower plate body are provided with a plurality of grooves, and the grooves on the upper plate body and the lower plate body are arranged side by side; micrometer and / or nanometer-level cavities are provided on the surface of the support column, and a plurality of support columns are sandwiched between the upper plate body and the lower plate body in the chamber, and the plurality of support columns are evenly distributed in the chamber; the working fluid is sealed in the chamber.

[0010] Preferably, the heat spreader is designed to be a quadrilateral, a circle, a trapezoid or the like according to the required heat transfer shape.

[0011] Preferably, the cross-sectional shape of the heat spreader channel is trapezoidal, V-shaped, or inverted Ω-shaped.

[0012] Preferably, the grooves on the upper plate body and the lower plate body are straight grooves or curved grooves, and the grooves on the upper plate body and the lower plate body are distributed at equal intervals or gradually.

[0013] Preferably, the support column is a cylinder or a polygonal column.

[0014] To solve the second technical problem mentioned above, the technical solution adopted in this application is: a method for manufacturing an integrated ceramic heat sink structure based on a tape casting method, comprising the following steps:

[0015] Step 1: using an atomization method to prepare micron or / and nanometer-sized paraffin particles, mixing the paraffin particles with a prefabricated ceramic slurry evenly and then molding them into support columns;

[0016] Step 2: evenly arrange the support columns obtained in step 1 inside the mold, pour molten paraffin into the mold, wait for the paraffin to solidify to obtain a solidified body, and process the upper and lower surfaces of the solidified body into grooves in the reverse shape to obtain a paraffin mold core;

[0017] Step 3: scrape the bottom of the lower plate of the heat spreader with ceramic slurry by tape casting, place the paraffin mold core on the bottom of the lower plate, and then scrape the upper plate of the heat spreader so that the paraffin film core is sealed between the upper plate and the lower plate;

[0018] Step 4: a working fluid injection port communicating with the chamber between the upper plate and the lower plate is provided on the surface of the vapor chamber, and the vapor chamber is sintered to gasify the paraffin wax to form an integrated ceramic vapor chamber;

[0019] Step 5: Evacuate the integrated ceramic heat sink through the working fluid injection port and inject the working fluid, and seal the working fluid injection port.

[0020] Preferably, in step 1, the ceramic slurry is one of aluminum oxide, aluminum nitride, silicon nitride and boron nitride, or a mixture of several of them.

[0021] Preferably, in step 6, the heat spreader is integrally sintered by using a low-temperature gradient sintering process or a high-temperature gradient sintering process.

[0022] The technical effects achieved by adopting the above technical solution are:

[0023] The integrated ceramic vapor chamber structure based on the tape casting method of the present invention comprises an upper plate body, a lower plate body, a support column and a working fluid, and a channel and a working fluid injection port are provided on the vapor chamber, wherein the surface of the support column has micrometer or / and nanometer-level cavities, and the vapor chamber structure is an integrated molding structure, and the goals of good thermal conductivity and heat uniformity can be achieved through the integrated vapor chamber structure. The setting of the support column makes the shape and size of the vapor chamber unconstrained; the surface of the support column has micrometer or / and nanometer-level cavities, and the porous structure can effectively enhance the boiling heat transfer of the vapor chamber, increase the critical heat flux of the vapor chamber, and thus significantly improve the heat transfer performance of the vapor chamber.

[0024] The support column is a cylinder or a polygonal column, so that the support column can be easily processed.

[0025] The present invention proposes a method for manufacturing an integrated ceramic heat sink structure based on a tape casting method, which has the following advantages:

[0026] (1) Paraffin is processed by atomization to obtain micron or / and nanometer paraffin particles, the paraffin particles are mixed with ceramic slurry in a certain proportion, and the ceramic slurry with paraffin particles is molded into a support column. The paraffin particles disappear at high temperature to obtain micro or / and nanometer cavities. This porous structure can effectively enhance the boiling heat transfer of the heat spreader and increase the critical heat flux of the heat spreader, thereby significantly improving the heat transfer performance of the heat spreader.

[0027] (2) There is no pressure during the implementation of the tape casting method, which avoids the "reverse shape" of the groove being crushed or the difficulty of laser processing of complex shapes, greatly reducing the restrictions of the ceramic material on the shape of the groove and effectively improving the reflux capacity of the working fluid; the tape casting method is integrated sintering and molding, which greatly avoids the cracking and leakage of the ceramic heat sink due to the difficulty of welding the upper and lower plates or the loose bonding.

[0028] (3) The grooves are machined by paraffin or molded. During the casting process, there is almost no force, so the cross-sectional shape of the grooves can be trapezoidal, "V"-shaped, inverted "Ω"-shaped, etc., or a composite shape of multiple simple geometric shapes, or even a three-dimensional shape; the spacing of the grooves can be the same or gradually changed; there is no substantial restriction on the groove depth and the plate thickness, and the deeper the groove depth, the better.

[0029] (4) Through the casting method, first scrape the lower plate of the heat spreader, put in the paraffin mold core, and then scrape the upper plate of the heat spreader to seal the paraffin film core between the upper and lower plates. After drying and sintering, an integrated ceramic heat spreader is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] Figure 1 It is a schematic diagram of the internal structure of an integrated ceramic heat sink based on the tape casting method;

[0032] Figure 2 It is a schematic diagram of the support column structure;

[0033] Figure 3 This is a top view of the wax mold core of the integrated ceramic soaking plate;

[0034] Figure 4 It is a side view of the paraffin mold core;

[0035] Figure 5 This is a schematic diagram of the tape casting process used in this application;

[0036] Figure 6 It is a structural schematic diagram of the lower plate;

[0037] Figure 7 The schematic diagram of the processing flow of the integrated ceramic heat sink based on the tape casting method of the present application is shown;

[0038] In the figure, 1, lower plate; 2, groove; 3, support column; 4, upper plate; 5, cavity; 6, paraffin mold core; 8, reverse shape of groove; 9, injection port; 10, scraper; 11, ceramic slurry. DETAILED DESCRIPTION

[0039] like Figures 1 to 4As shown, an integrated ceramic heat spreader structure based on the tape casting method includes a heat spreader, a support column 3 and a working fluid. The heat spreader includes an upper plate body 4 and a lower plate body 1, and a chamber is provided between the upper plate body 4 and the lower plate body 1, and the middle chamber is evacuated to facilitate the injection of the working fluid. The heat spreader is designed to be a quadrilateral, a circle or a trapezoid according to the required heat transfer shape. The bottom surface of the upper plate body 4 and the top surface of the lower plate body 1 are provided with a plurality of grooves 2, and the structure of the groove 2 is preferably formed by the reverse shape 8 of the groove on the paraffin mold core 6, which is sintered at a high temperature to make the paraffin mold core 6 disappear. The grooves 2 on the upper plate body 4 and the lower plate body 1 are arranged side by side. The grooves 2 on the upper plate body 4 and the lower plate body 1 are straight grooves or curved grooves. The grooves 2 are machined or molded by paraffin, so the cross-sectional shape of the grooves 2 can be trapezoidal, "V"-shaped or inverted "Ω"-shaped. The cross-sectional shape of the grooves 2 can also be a composite of multiple simple geometric shapes. The spacing of the grooves 2 can be the same or gradually changed. There is no substantial restriction on the depth of the grooves 2 and the thickness of the plate, and the deeper the grooves 2, the better.

[0040] The surface of the support column 3 is provided with micrometer or / and nanometer-level cavities 5, and a plurality of support columns 3 are sandwiched between the upper plate 4 and the lower plate 1 in the chamber, and the plurality of support columns 3 are evenly distributed in the chamber; the support column 3 is a cylinder or a multi-prism. A working fluid is sealed in the chamber.

[0041] like Figures 5 to 7 As shown, the method for manufacturing an integrated ceramic heat sink structure based on the tape casting method of the present application includes the following steps:

[0042] Step 1: Use an atomization method to prepare micron or / and nanometer paraffin particles, mix the paraffin particles with the prefabricated ceramic slurry 11 evenly, and then mold them into support columns 3. Specifically, paraffin is processed by an atomization method to obtain micron or / and nanometer paraffin particles, the paraffin particles are mixed with the ceramic slurry 11 in a certain proportion, and the ceramic slurry 11 with paraffin particles is molded into a support column 3. The ceramic slurry 11 is one of aluminum oxide, aluminum nitride, silicon nitride and boron nitride, or a mixture of several of them. The paraffin particles disappear at high temperature to obtain micron or / and nanometer cavities 5. The porous structure can effectively enhance the boiling heat transfer of the heat spreader, increase the critical heat flux of the heat spreader, and thus significantly improve the heat transfer performance of the heat spreader.

[0043] Step 2: Arrange the support columns 3 obtained in step 1 evenly inside the mold, pour molten paraffin into the mold, wait for the paraffin to solidify to obtain a solid body, and process the groove 2 in the reverse shape on the upper and lower surfaces of the solid body to obtain a paraffin mold core 6.

[0044] Step 3: Use a scraper 10 to scrape out the lower plate 1 of the heat spreader by the casting method, place the paraffin mold core 6 on the lower plate 1, and then use the scraper 10 to scrape out the upper plate 4 of the heat spreader, so that the paraffin film core is sealed between the upper plate 4 and the lower plate 1. Through the casting method, use a scraper 10 to scrape the lower plate of the heat spreader first, put in the paraffin mold core 6, and then scrape the upper plate 4 of the heat spreader, so that the paraffin film core 6 is sealed between the upper and lower plates, and after drying and sintering, an integrated ceramic heat spreader is obtained. The use of the casting method reduces the effect of force, avoids the structural uniformity of the grooves processed by laser processing and pressure processing, and makes it possible for the groove structure to be a three-dimensional structure. The casting method is integrated and formed, and at the same time, it also avoids the cracking and leakage of the ceramic heat spreader due to the difficulty of welding the upper and lower plates or the unreliable bonding. There is no pressure during the implementation of the casting method, which avoids the "reverse shape" of the groove 2 from being crushed or the difficulty of laser processing of complex shapes, greatly reducing the restrictions of the ceramic material on the shape of the groove 2 and improving the reflux capacity of the working fluid.

[0045] Step 4: a working fluid injection port 9 communicating with the chamber is provided on the surface of the heat spreader, and the heat spreader is sintered to gasify the paraffin wax to form an integrated ceramic heat spreader. Preferably, the heat spreader is integrally sintered by a low-temperature gradient sintering process or a high-temperature gradient sintering process.

[0046] Step 5: Evacuate the integrated ceramic heat spreader and inject the working fluid through the working fluid injection port 9, and seal the working fluid injection port 9. The working fluid injection port 9 can be located on the upper plate body 4 or the lower plate body 1 of the heat spreader, or on the side of the heat spreader, depending on the actual situation. Evacuate the sintered ceramic heat spreader and inject the working fluid through the working fluid injection port 9, and finally seal the working fluid injection port 9. The working fluid can be one of deionized water, ammonia, methanol, Freon, acetone, etc., or a mixture of several of them that is compatible with ceramic materials. The amount of injection and the degree of vacuuming depend on the working conditions of the heat dissipation device.

[0047] The integrated ceramic heat spreader of the present application includes an upper body 4, a lower plate body 1, a support column 3 and a working fluid, and a groove 2 and a working fluid injection port 9 are provided on the heat spreader, wherein the surface of the support column 3 has micrometer or / and nanometer-level cavities 5, and the heat spreader structure is an integrated molding structure, and through the integrated heat spreader structure, the goal of good thermal conductivity and heat spread can be achieved. The setting of the support column 3 makes the shape and size of the heat spreader unconstrained; the surface of the support column 3 has micrometer or / and nanometer-level cavities 5, and the porous structure can effectively enhance the boiling heat transfer of the heat spreader, increase the critical heat flux of the heat spreader, and thus significantly improve the heat transfer performance of the heat spreader.

Claims

1. A method for manufacturing an integrated ceramic heat sink structure based on a tape casting method, characterized in that: include: A heat spreader, the heat spreader comprising an upper plate body and a lower plate body, a chamber is provided between the upper plate body and the lower plate body, a plurality of grooves are provided on the bottom surface of the upper plate body and the top surface of the lower plate body, and the grooves on the upper plate body and the lower plate body are arranged side by side; Support pillars, each of which has micrometer-scale or / and nanometer-scale cavities on its surface, a plurality of said support pillars being sandwiched between the upper plate and the lower plate in the chamber, and the plurality of said support pillars being evenly distributed in the chamber; and The working fluid is sealed in the chamber, and the manufacturing method comprises the following steps: Step 1: using an atomization method to prepare micron or / and nanometer-sized paraffin particles, mixing the paraffin particles with a prefabricated ceramic slurry evenly and then molding them into support columns; Step 2: evenly arrange the support columns obtained in step 1 inside the mold, pour molten paraffin into the mold, wait for the paraffin to solidify to obtain a solidified body, and process the upper and lower surfaces of the solidified body into grooves in the reverse shape to obtain a paraffin mold core; Step 3: scrape the bottom of the lower plate of the heat spreader with ceramic slurry by tape casting, place the paraffin mold core on the bottom of the lower plate, and then scrape the upper plate of the heat spreader to seal the paraffin film core between the upper plate and the lower plate; Step 4: a working fluid injection port communicating with the chamber between the upper plate and the lower plate is provided on the surface of the vapor chamber, and the vapor chamber is sintered to gasify the paraffin wax to form an integrated ceramic vapor chamber; Step 5: Evacuate the integrated ceramic heat sink through the working fluid injection port and inject the working fluid, and seal the working fluid injection port.

2. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 1, characterized in that: The heat spreader is designed to be a quadrilateral, a circle or a trapezoid according to the required heat transfer shape.

3. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 1, characterized in that: The cross-sectional shape of the heat spreader channel is trapezoidal, V-shaped or inverted Ω-shaped.

4. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 1, characterized in that: The grooves on the upper plate body and the lower plate body are straight grooves or curved grooves, and the grooves on the upper plate body and the lower plate body are distributed at equal intervals or gradually.

5. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 1, characterized in that: The support column is a cylinder or a polygonal column.

6. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 1, characterized in that: The working fluid is one of deionized water, ammonia, methanol, freon, and acetone, or a mixture of several of them, which is compatible with ceramic materials.

7. The method for manufacturing an integrated ceramic vapor chamber structure based on a tape casting method according to claim 6, characterized in that: In step 1, the ceramic slurry is one or a mixture of several of aluminum oxide, aluminum nitride, silicon nitride and boron nitride.

8. The method for manufacturing an integrated ceramic vapor chamber structure based on tape casting method according to claim 1, characterized in that: In step 4, the heat spreader is integrally sintered by using a low-temperature gradient sintering process or a high-temperature gradient sintering process.

Images