Laser direct writing of wick structure ultra-thin ceramic vapor chamber and preparation method thereof
By forming an ultra-thin ceramic heat sink with a cross-groove structure on a ceramic frame using laser direct writing, the problems of large thickness, high processing difficulty, and poor packaging reliability of existing ceramic heat sinks are solved. This achieves efficient and uniform heat dissipation performance and reliable packaging, making it suitable for miniaturized electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2025-11-07
- Publication Date
- 2026-05-15
AI Technical Summary
Existing ceramic heat sinks are too thick, making it difficult to meet the heat dissipation requirements of semiconductor power devices as they develop towards high power, miniaturization, and multi-functionality. Traditional ceramic heat sinks are difficult to process with microgrooves, have insufficient capillary capacity and permeability, and suffer from problems such as encapsulation cracking and air leakage, resulting in low heat dissipation efficiency.
A cross-groove liquid-absorbing core structure is formed on a ceramic frame using laser direct writing technology. Combined with sealant or laser welding encapsulation, an ultrathin ceramic heat sink is prepared with a thickness of 0.1-1 mm, a microgroove width of 5-50 μm, a depth of 3-30 μm, and a groove spacing of 10-100 μm. The working liquid is deionized water, ethanol, acetone, or a mixture thereof.
It achieves efficient heat transfer and uniform heat dissipation of ultra-thin ceramic heat sinks, solving the problems of large thickness, difficult processing and poor packaging reliability of traditional ceramic heat sinks. It improves capillary force and permeability, simplifies the packaging structure and extends service life.
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Figure CN121252540B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ceramic heat exchanger technology, specifically to an ultrathin ceramic heat exchanger with a laser-written liquid-absorbing core structure and its preparation method. Background Technology
[0002] With the rapid development of semiconductor devices, semiconductor power devices are rapidly developing towards high power, miniaturization and multi-functionality. However, as the local heat flux density continues to increase, its power density also increases. The integration of semiconductor power devices leads to uneven heat distribution.
[0003] As a new type of high-efficiency heat exchange technology, vapor chambers are high-efficiency and energy-saving heat exchange devices. Their energy-saving properties are particularly prominent in the thermal management scenarios of high-power and thin electronic devices. Through the extremely high heat transfer coefficient brought about by gas-liquid phase change, they can achieve good temperature uniformity and rapid start-up, and quickly transfer the heat generated by power devices. They are an effective method to solve the heat dissipation problem of various electronic device circuits such as semiconductor devices and high-computing-power chips.
[0004] However, existing ceramic heat spreaders have the following technical problems:
[0005] Existing ceramic vapor chambers are too thick, making it difficult to meet the heat dissipation requirements of semiconductor power devices as they evolve towards higher power, miniaturization, and multifunctionality. Traditional ceramic vapor chambers are difficult to fabricate with microgrooves, and the groove morphology is limited, resulting in insufficient capillary capacity and permeability. This leads to low liquid working fluid reflux efficiency and poor thermal conductivity and heat dissipation performance. There are also issues with the welding cracking of the upper and lower shell plates, which can easily cause air leakage after packaging, seriously affecting the heat dissipation performance and lifespan of the equipment. Traditional semiconductor power devices and high-performance chips have long heat dissipation paths, requiring heat to be transferred to the heat sink through the chip bonding layer, ceramic substrate, substrate bonding layer, and thermally conductive interface material (TIM) on the substrate. This results in low heat dissipation efficiency and a complex packaging structure.
[0006] Therefore, it is of great significance to manufacture an ultrathin ceramic heat sink with good heat distribution, insulation, high capillary force and permeability, and good thermal matching with semiconductor power devices and chips. Summary of the Invention
[0007] To address the problems existing in the prior art, the purpose of this invention is to provide an ultrathin ceramic heat sink with a laser direct-write liquid wick structure and its preparation method, which has excellent performance, reliability and adaptability of ultrathin ceramic heat sinks, and provides an integrated heat dissipation solution for miniaturized electronic devices.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A laser-written liquid-absorbing core structure ultrathin ceramic heat spreader includes a ceramic upper shell plate, a ceramic lower shell plate, and a ceramic middle frame;
[0010] A cavity is formed between the ceramic upper shell plate and the ceramic lower shell plate. The ceramic middle frame is set in the cavity. The outer side of the ceramic middle frame is reserved with the inner side of the ceramic upper shell plate and the ceramic lower shell plate respectively. It is sealed with the ceramic upper shell plate and the ceramic lower shell plate by one of the following sealing methods: sealant, laser welding or low temperature slurry.
[0011] A microgroove liquid-absorbing core structure is formed on the ceramic frame using laser direct writing. The microgroove liquid-absorbing core structure includes transverse microgrooves and longitudinal microgrooves. The ceramic frame is divided into a condensation zone, an insulation zone, and an evaporation zone along the heat transfer direction of the heat spreader. Transverse microgrooves are provided in the condensation zone, insulation zone, and evaporation zone along the heat transfer direction of the heat spreader. Longitudinal microgrooves are also provided on the transverse microgrooves in the condensation zone and the evaporation zone. The longitudinal microgrooves are perpendicular to the transverse microgrooves. The depth of the transverse microgrooves is greater than the depth of the longitudinal microgrooves.
[0012] The total thickness of the ultra-thin ceramic heat spreader is 0.1-1mm, and the thicknesses of the ceramic upper shell, ceramic lower shell, and ceramic middle frame are 0.05-0.3mm, respectively.
[0013] Furthermore, the ceramic upper shell plate, ceramic lower shell plate, and ceramic middle frame are made of one or more of aluminum nitride, aluminum oxide, and zirconium oxide.
[0014] Furthermore, the microgroove structure in the condensation zone and evaporation zone is rhomboid in shape, while the microgroove structure in the adiabatic zone is vertical; the cross-sectional shape of the microgroove is V-shaped.
[0015] Furthermore, the width of the microgrooves is 5-50 μm, the depth is 3-30 μm, the groove spacing is 10-100 μm, and the depth-to-width ratio between the transverse and longitudinal microgrooves is 0.5-1.5.
[0016] Furthermore, the chamber is filled with a liquid working medium, which is one or more of deionized water, ethanol, acetone, and methanol.
[0017] Furthermore, the ceramic frame is provided with a liquid injection port, which protrudes 1-3mm from the surface of the ceramic frame and is connected to the cavity.
[0018] A method for preparing an ultrathin ceramic heat exchanger with a laser-written liquid-absorbing core structure includes the following steps:
[0019] Step 1: Prepare the ceramic middle frame. Cut strip structures on the ceramic middle frame using laser cutting technology. Control the overall cutting size of the ceramic middle frame to be smaller than the ceramic upper shell plate and the ceramic lower shell plate. At the same time, set the liquid injection port on the surface of the ceramic middle frame so that the liquid injection port protrudes 1-3mm from the ceramic middle frame.
[0020] Step 2: Using the ceramic frame with strip-shaped structure and injection port prepared in Step 1 as the substrate, a microgroove liquid-absorbing core structure is laser-written on the substrate; wherein, the microgroove liquid-absorbing core structure includes transverse microgrooves and longitudinal microgrooves, the ceramic frame is divided into a condensation zone, an insulation zone and an evaporation zone in sequence along the heat transfer direction of the heat spreader, the condensation zone, the insulation zone and the evaporation zone are all provided with transverse microgrooves along the heat transfer direction of the heat spreader, and the transverse microgrooves of the condensation zone and the evaporation zone are provided with longitudinal microgrooves, the longitudinal microgrooves are perpendicular to the transverse microgrooves, and the depth of the transverse microgrooves is greater than the depth of the longitudinal microgrooves;
[0021] Step 3: Place the ceramic middle frame with microgroove liquid absorption core structure prepared in Step 2 between the ceramic upper shell plate and the ceramic lower shell plate, and seal the ceramic upper shell plate, ceramic lower shell plate and ceramic middle frame with one of the following sealing methods: sealant, laser welding or low temperature slurry, and leave the liquid injection port set in Step 1 during sealing.
[0022] Step 4: Vacuum the encapsulated chamber through the injection port reserved in Step 3, then inject liquid working fluid into the chamber, and finally seal the injection port to obtain an ultrathin ceramic heat sink with a laser direct writing liquid wick structure.
[0023] Furthermore, in step 1, the upper and lower ceramic shell plates are made of alumina ceramic, and the middle ceramic frame is made of zirconia ceramic.
[0024] Furthermore, in step 2, during laser direct writing, firstly, transverse microgrooves are directly written in the condensation zone, insulation zone, and evaporation zone of the ceramic frame, and then longitudinal microgrooves are directly written on the transverse microgrooves in the condensation zone and evaporation zone to form a microgrooved liquid-absorbing core structure.
[0025] Furthermore, in step 3, when using sealant for sealing, the sealant is applied to the 1-3mm gap reserved between the ceramic middle frame and the ceramic upper and lower shell plates, avoiding the injection port area.
[0026] In summary, the present invention has the following advantages:
[0027] Ultra-thin design and improved adaptability: The total thickness of the heat spreader is controlled at 0.1-1mm, which can adapt to the installation requirements of miniaturized electronic devices such as chips. This solves the problem that traditional ceramic heat spreaders cannot be used for chips due to their large thickness. At the same time, it can replace the original ceramic substrate, substrate welding layer and substrate, simplifying the packaging structure of electronic devices.
[0028] Optimization of heat transfer efficiency and heat distribution performance: The use of laser direct writing technology to form a cross-grooved micro-groove liquid wick structure on the ceramic frame greatly improves the capillary force and permeability of the liquid wick, and accelerates the return of the liquid working fluid; the gas-liquid coplanar structure reduces the resistance to vapor flow, which significantly improves the heat transfer capacity of the heat spreader, enabling it to quickly and evenly transfer the heat generated by electronic devices, and effectively solve the problems of high local heat flux density and uneven heat distribution.
[0029] Enhanced processing and packaging reliability: Laser direct writing processing allows for free design of microgroove shapes, avoiding ceramic cracking problems caused by traditional machining; the reserved gap on the outer side of the ceramic frame is used for bonding and sealing, combined with sealing methods such as sealant, laser welding or low-temperature slurry, effectively avoiding cracking, liquid leakage and gas leakage caused by traditional welding processes, improving the yield and service life of heat spreader packaging.
[0030] Improved convenience of liquid injection and vacuum treatment: The liquid injection port on the ceramic middle frame protrudes 1-3mm from the surface of the middle frame and is completely isolated from the pre-reserved sealing gap. This not only avoids the sealant clogging the liquid injection port during encapsulation, but also facilitates the vacuuming and liquid working fluid injection operations in the chamber, ensuring that the vacuum degree and working fluid injection volume in the chamber meet the design requirements, and further ensuring the stability of the heat dissipation performance of the heat spreader. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the exploded structure of an ultrathin ceramic heat sink.
[0032] Figure 2 A top view of the ceramic midframe after laser direct writing with microgrooves;
[0033] Figure 3 A top view of the intersecting horizontal and vertical sections of the laser-written microgrooves on the ceramic midframe;
[0034] Figure 4 for Figure 3 A side view diagram;
[0035] Figure 5 for Figure 3 A frontal view diagram;
[0036] Among them, 1. Ceramic upper shell plate; 2. Ceramic middle frame; 3. Ceramic lower shell plate; 4. Intersecting horizontal and vertical parts; 41. Longitudinal micro-grooves; 42. Transverse micro-grooves; 5. Chamber. Detailed Implementation
[0037] The present invention will now be described in further detail.
[0038] like Figures 1-5 As shown, an ultrathin ceramic heat spreader with a laser direct-write liquid absorption core structure includes a ceramic upper shell plate 1, a ceramic lower shell plate 3, and a ceramic middle frame 2.
[0039] A chamber 5 is formed between the upper ceramic shell plate 1 and the lower ceramic shell plate 3, serving as the vapor chamber for the ceramic heat exchanger. A ceramic middle frame 2 is disposed within the chamber 5, serving as the liquid-absorbing core and support structure for the ultra-thin ceramic heat exchanger. A gap is reserved on the outer side of the ceramic middle frame 2, which is sealed to the inner sides of the upper ceramic shell plate 1 and the lower ceramic shell plate 3. A liquid injection port is provided on the ceramic middle frame 2, protruding 1-3 mm from its surface and connected to the chamber 5. A liquid working medium is filled into the chamber 5 through the injection port. The liquid working medium is one or a mixture of deionized water, ethanol, acetone, and methanol. The injection volume and vacuum level depend on the operating conditions of various devices such as semiconductor devices and chips.
[0040] A microgrooved liquid-absorbing core structure is formed on the ceramic frame 2 using laser direct writing. This provides a gas-liquid coplanar structure for the ultra-thin ceramic heat exchanger plate, improving the reflux capacity of the working fluid and the capillary force and permeability of the liquid-absorbing core, thus significantly enhancing the heat transfer capacity of the heat exchanger plate. The microgrooved liquid-absorbing core structure includes transverse microgrooves 42 and longitudinal microgrooves 41. The ceramic frame 2 is divided into a condensation zone, an adiabatic zone, and an evaporation zone along the heat transfer direction of the heat exchanger plate. Each of the condensation zone, adiabatic zone, and evaporation zone has transverse microgrooves 42 along the heat transfer direction of the heat exchanger plate. The transverse microgrooves 42 in the condensation zone and the evaporation zone also have longitudinal microgrooves 41 perpendicular to the transverse microgrooves 42, forming a cross-sectional and cross-sectional mesh structure 4, simulating the role of a wire mesh within the heat exchanger plate.
[0041] The depth of the transverse microgroove 42 is greater than the depth of the longitudinal microgroove 41. The transverse microgroove 42 enhances capillary force to accelerate liquid reflux, while the longitudinal microgroove 41 widens the vapor channel to reduce flow resistance, enabling the ultrathin ceramic heat spreader to achieve good thermal conductivity.
[0042] In this embodiment, the total thickness of the ultra-thin ceramic heat spreader is 0.1-1mm, wherein the thicknesses of the ceramic upper shell plate 1, the ceramic lower shell plate 3, and the ceramic middle frame 2 are 0.05-0.3mm, respectively.
[0043] The ceramic upper shell plate 1, the ceramic lower shell plate 3, and the ceramic middle frame 2 are made of one or more of aluminum nitride, aluminum oxide, and zirconium oxide.
[0044] The microgrooves in the condensation and evaporation zones are rhomboid in shape, while those in the adiabatic zone are vertical. The cross-sectional shape of the microgrooves is V-shaped.
[0045] In this embodiment, the width of the microgrooves is 5-50 μm, the depth is 3-30 μm, the groove spacing is 10-100 μm, and the aspect ratio between the transverse microgrooves 42 and the longitudinal microgrooves 41 is 0.5-1.5. If the depth of the transverse microgrooves 42 is 2 μm, and the aspect ratio between the transverse microgrooves 42 and the longitudinal microgrooves 41 is 0.5, then the depth of the longitudinal microgrooves 41 is 2 × 0.5 = 1 μm; if the width of the transverse microgrooves 42 is 20 μm, and the aspect ratio is 1.5, then the depth of the transverse microgrooves 42 is 20 × 1.5 = 30 μm.
[0046] The ultrathin ceramic heat exchanger plate of this invention, featuring a laser-direct-writing wick structure, achieves efficient heat dissipation based on the gas-liquid phase change heat transfer principle and capillary action. The microgrooved wick structure on the ceramic frame 2 provides strong capillary force. The liquid working fluid absorbs heat generated by the electronic devices in the evaporation zone and vaporizes. The resulting vapor flows towards the condensation zone under the influence of concentration and temperature differences. After releasing heat in the condensation zone, the vapor re-condenses into liquid. The liquid then flows back to the evaporation zone under the capillary pumping action of the microgrooved wick, completing one heat transfer cycle and achieving rapid heat transfer and uniform distribution. Simultaneously, the microgrooved wick structure and the vapor chamber form a gas-liquid coplanar structure, reducing vapor flow resistance and further improving heat transfer efficiency.
[0047] A method for preparing an ultrathin ceramic heat exchanger with a laser-written liquid-absorbing core structure includes the following steps:
[0048] Step 1: Prepare ceramic middle frame 2. Cut strip-shaped structures on ceramic middle frame 2 using laser cutting technology. Control the overall cutting size of ceramic middle frame 2 to be smaller than ceramic upper shell plate 1 and ceramic lower shell plate 3. The reserved gap greatly avoids air and liquid leakage of sealant. At the same time, set liquid injection port on the surface of ceramic middle frame 2, so that the liquid injection port protrudes 1-3 mm from ceramic middle frame 2.
[0049] Step 2: Using the ceramic frame with strip structure and injection port prepared in Step 1 as the substrate, a microgroove liquid-absorbing core structure is laser-written on the substrate; wherein, the microgroove liquid-absorbing core structure includes transverse microgrooves 42 and longitudinal microgrooves 41. The ceramic frame 2 is divided into a condensation zone, an insulation zone and an evaporation zone along the heat transfer direction of the heat spreader. The condensation zone, insulation zone and evaporation zone are all provided with transverse microgrooves 42 along the heat transfer direction of the heat spreader. The transverse microgrooves 42 in the condensation zone and the evaporation zone are provided with longitudinal microgrooves 41. The longitudinal microgrooves 41 are perpendicular to the transverse microgrooves 42. The depth of the transverse microgrooves 42 is greater than the depth of the longitudinal microgrooves 41.
[0050] The main function of the transverse microgrooves 42 is to transport the liquid working fluid from the condensation zone to the evaporation zone, while the main function of the longitudinal microgrooves 41 is to reduce the flow resistance by longitudinally transmitting the gas between the evaporation zone and the condensation zone, ensuring that the steam flow and liquid return do not interfere with each other, so that the ultra-thin ceramic heat spreader can achieve better heat transfer performance and temperature uniformity.
[0051] Figure 2 , Figure 4 , Figure 5 In the figure, a represents the length of the intersecting portion 4 of the laser-written microgroove in the ceramic frame 2; b represents the width of the intersecting portion 4 of the laser-written microgroove in the ceramic frame 2.
[0052] Step 3: Place the ceramic middle frame 2 with microgroove liquid absorption core structure prepared in Step 2 between the ceramic upper shell plate 1 and the ceramic lower shell plate 3. Use one of the following sealing methods to encapsulate the ceramic upper shell plate 1, the ceramic lower shell plate 3 and the ceramic middle frame 2, and leave the liquid injection port set in Step 1 during encapsulation.
[0053] Step 4: Vacuum the encapsulated chamber 5 through the injection port reserved in Step 3, then inject liquid working fluid into the chamber 5, and finally seal the injection port to obtain an ultrathin ceramic heat sink with a laser direct writing liquid wick structure.
[0054] Preferably, in step 1, the upper ceramic shell plate 1 and the lower ceramic shell plate 3 are made of alumina ceramic, and the middle ceramic frame 2 is made of zirconia ceramic.
[0055] Preferably, in step 3, when using sealant for sealing, the sealant is applied to the 1-3mm gap reserved between the ceramic middle frame 2 and the ceramic upper shell plate 1 and the ceramic lower shell plate 3, avoiding the injection port area.
[0056] Work process:
[0057] Heat absorption stage: When electronic devices such as semiconductor power devices and high-performance chips generate heat during operation, the heat is transferred to the evaporation zone of the ultra-thin ceramic heat sink. After absorbing heat, the liquid working fluid in the evaporation zone rapidly undergoes a vaporization reaction and transforms into a vapor state. This process achieves heat absorption.
[0058] Steam Flow Stage: Due to its own thermal expansion and the temperature and pressure differences between the evaporation and condensation zones, the steam generated in the evaporation zone flows towards the condensation zone through the intermediate adiabatic zone. During the flow, the steam is rapidly transported through the longitudinal microgrooves 41 in the microgrooved liquid-absorbing core structure of the ceramic frame 2. Since the longitudinal microgrooves 41 are mainly used for gas transport, and the gas-liquid coplanar structure reduces the steam flow resistance, it ensures that the steam reaches the condensation zone efficiently.
[0059] Heat release stage: After steam reaches the condensation zone, it comes into contact with the cooler ceramic upper shell plate 1 and ceramic lower shell plate 3, releasing the heat absorbed during the evaporation stage, and then re-condenses into a liquid working fluid. The released heat is transferred to the external environment or radiator through the ceramic upper shell plate 1 and ceramic lower shell plate 3, completing the heat release.
[0060] Liquid reflux stage: Under the capillary force of the microgroove wicking structure in the ceramic frame 2, the condensed liquid working fluid flows back to the evaporation zone along the transverse microgrooves 42. The transverse microgrooves 42 are densely distributed in the condensation and evaporation zones and cooperate with the longitudinal microgrooves 41 to form an efficient reflux channel, ensuring that the liquid working fluid can continuously and stably return to the evaporation zone, preparing for the next heat transfer cycle, thereby realizing the continuous heat dissipation of electronic devices by the heat spreader.
[0061] This invention constructs an integrated structural system of a laser-written partitioned microgroove liquid-absorbing core and an ultra-thin ceramic middle frame 2 support. This system represents a systematic breakthrough from structural design and processing technology to functional realization, precisely solving two core technical bottlenecks: the imbalance between capillary performance and vapor flow efficiency of ultra-thin ceramic heat spreaders, and the contradiction between processing accuracy and packaging reliability. Specifically, this is reflected in the following three aspects of deep coupling innovation:
[0062] Structural Innovation: Zoned Functional Microgroove Liquid Absorber Achieves Highly Efficient Gas-Liquid Synergy
[0063] This invention overcomes the design limitations of traditional liquid-absorbing cores that use a single groove morphology to adapt to the entire area. Based on the functional differences between the evaporation zone, insulation zone, and condensation zone within the heat spreader, it constructs a differentiated microgroove layout using laser direct writing technology, forming a core structural advantage of gas-liquid coplanarity and zoned flow guidance.
[0064] Functional Zoning Design: The evaporation and condensation zones employ a cross structure of transverse microgrooves 42 and longitudinal microgrooves 41. The transverse grooves enhance capillary force to accelerate liquid reflux, while the longitudinal grooves widen the vapor channel to reduce flow resistance. The insulation zone retains only the transverse microgrooves 42, focusing on liquid transport while avoiding interference with vapor flow. This design enables the suction core to simultaneously meet the high capillary pressure required for liquid reflux and the high vapor permeability that reduces phase change cycle resistance, solving the industry-wide problem of mutual obstruction between gas and liquid flow within ultra-thin cavities.
[0065] Precise parameter matching: The combination of parameters, including a microgroove width of 5-50μm, a depth of 3-30μm, and an aspect ratio of 0.5-1.5, is an optimization result based on the characteristics of ceramic materials and the precision of laser processing. This ensures the structural strength of ceramic substrates such as aluminum nitride and zirconium oxide, while achieving an optimal balance between capillary force and liquid reflux efficiency, far exceeding the performance limit of traditional casting composite wicks.
[0066] The partitioned microgroove structure of the present invention does not require additional composite components and is directly integrally formed on the ceramic inner frame 2, which reduces assembly errors and adapts to the ultra-thin thickness requirements of 0.1-1mm, achieving a balance between structural simplification and performance enhancement.
[0067] Process Innovation: End-to-End Adaptation and Optimization of Laser Direct Writing and Ceramic Packaging
[0068] This application deeply integrates laser direct writing technology with the entire process of ceramic heat sink preparation, solving the traditional pain points of easy cracking and easy leakage in the processing of ultra-thin ceramic substrates and encapsulation:
[0069] Breakthrough in processing precision: By employing laser direct writing technology to replace traditional processes such as chemical etching and mechanical etching, complex grooves can be precisely formed on ceramic frames with a thickness of only 0.05-0.3mm. This avoids the ceramic brittleness problem caused by mechanical processing, and the groove morphology can be flexibly designed according to heat transfer requirements. The micron-level precision and flexibility of this processing method are difficult to achieve on ceramic substrates using techniques such as surface projection micro-stereolithography.
[0070] Upgraded packaging reliability: By designing a reserved gap of 1-3mm smaller than the upper and lower shell plates through the ceramic middle frame 2, combined with sealing methods such as sealant and laser welding, it not only provides space for sealing materials, but also avoids damage to the microgroove structure caused by direct welding; at the same time, the independent liquid injection port design protruding 1-3mm from the middle frame completely solves the process conflict between packaging and liquid injection, ensuring precise control of the vacuum degree of chamber 5 and the amount of working fluid injected.
[0071] This end-to-end design, which integrates processing, packaging, and liquid injection, significantly improves the yield of ultra-thin ceramic heat spreaders compared to traditional processes, effectively solving the problem of difficult assembly of support columns and liquid absorption cores in existing technologies.
[0072] Application Innovation: A Dual Breakthrough in Ultra-Thin Design and Functional Integration
[0073] This application achieves a dual breakthrough in ultra-thin heat dissipation plates and functional integration through synergistic innovation in structure and process, breaking through the application limitations of traditional heat dissipation components:
[0074] Ultra-thin adaptability: By optimizing the thickness of the upper shell, lower shell, and middle frame (single component thickness 0.05-0.3mm, total thickness 0.1-1mm), the heat sink can directly replace the combination of ceramic substrate, solder layer, and substrate of semiconductor power devices, greatly shortening the heat dissipation path. This solves the core pain point of limited heat dissipation space for high-performance chips, achieving a comprehensive breakthrough in performance, reliability, and adaptability of ultra-thin ceramic heat sinks, and providing an integrated heat dissipation solution for miniaturized electronic devices.
[0075] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A laser-written liquid-absorbing core structure ultrathin ceramic heat sink, characterized in that: Includes a ceramic upper shell plate, a ceramic lower shell plate, and a ceramic middle frame with a strip structure; A cavity is formed between the ceramic upper shell plate and the ceramic lower shell plate. The ceramic middle frame is set in the cavity. The outer side of the ceramic middle frame is reserved with the inner side of the ceramic upper shell plate and the ceramic lower shell plate respectively. It is sealed with the ceramic upper shell plate and the ceramic lower shell plate by one of the following sealing methods: sealant, laser welding or low temperature slurry. A microgroove liquid-absorbing core structure is formed on the ceramic frame using laser direct writing. The microgroove liquid-absorbing core structure includes transverse microgrooves and longitudinal microgrooves. The ceramic frame is divided into a condensation zone, an insulation zone, and an evaporation zone along the heat transfer direction of the heat spreader. Transverse microgrooves are provided in the condensation zone, insulation zone, and evaporation zone along the heat transfer direction of the heat spreader. Longitudinal microgrooves are also provided on the transverse microgrooves in the condensation zone and the evaporation zone. The longitudinal microgrooves are perpendicular to the transverse microgrooves. The depth of the transverse microgrooves is greater than the depth of the longitudinal microgrooves. The total thickness of the ultra-thin ceramic heat spreader is 1mm, and the thicknesses of the ceramic upper shell, ceramic lower shell, and ceramic middle frame are 0.05-0.3mm respectively. The ceramic upper shell plate, ceramic lower shell plate, and ceramic middle frame are made of one or more of aluminum nitride, aluminum oxide, and zirconium oxide.
2. The ultra-thin ceramic heat spreader plate according to claim 1, characterized in that: The microgrooves in the condensation and evaporation zones are rhomboid in shape, while those in the adiabatic zone are vertical. The cross-sectional shape of the microgrooves is V-shaped.
3. The ultra-thin ceramic heat spreader plate according to claim 1, characterized in that: The width of the microgrooves is 5-50 μm, the depth is 3-30 μm, the groove spacing is 10-100 μm, and the depth-to-width ratio between the transverse and longitudinal microgrooves is 0.5-1.
5.
4. The ultra-thin ceramic heat spreader plate according to claim 1, characterized in that: The chamber is filled with a liquid working medium, which is one or more of deionized water, ethanol, acetone and methanol.
5. The ultra-thin ceramic heat spreader plate according to claim 1, characterized in that: The ceramic frame is provided with a liquid injection port, which protrudes 1-3mm from the surface of the ceramic frame and is connected to the cavity.
6. The method for preparing the ultrathin ceramic heat spreader according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Prepare the ceramic middle frame. Cut strip structures on the ceramic middle frame using laser cutting technology. Control the overall cutting size of the ceramic middle frame to be smaller than the ceramic upper shell plate and the ceramic lower shell plate. At the same time, set the liquid injection port on the surface of the ceramic middle frame so that the liquid injection port protrudes 1-3mm from the ceramic middle frame. Step 2: Using the ceramic frame with strip-shaped structure and injection port prepared in Step 1 as the substrate, a microgroove liquid-absorbing core structure is laser-written on the substrate; wherein, the microgroove liquid-absorbing core structure includes transverse microgrooves and longitudinal microgrooves, the ceramic frame is divided into a condensation zone, an insulation zone and an evaporation zone in sequence along the heat transfer direction of the heat spreader, the condensation zone, the insulation zone and the evaporation zone are all provided with transverse microgrooves along the heat transfer direction of the heat spreader, and the transverse microgrooves of the condensation zone and the evaporation zone are provided with longitudinal microgrooves, the longitudinal microgrooves are perpendicular to the transverse microgrooves, and the depth of the transverse microgrooves is greater than the depth of the longitudinal microgrooves; Step 3: Place the ceramic middle frame with microgroove liquid absorption core structure prepared in Step 2 between the ceramic upper shell plate and the ceramic lower shell plate, and seal the ceramic upper shell plate, ceramic lower shell plate and ceramic middle frame with one of the following sealing methods: sealant, laser welding or low temperature slurry, and leave the liquid injection port set in Step 1 during sealing. Step 4: Vacuum the encapsulated chamber through the injection port reserved in Step 3, then inject liquid working fluid into the chamber, and finally seal the injection port to obtain an ultrathin ceramic heat sink with a laser direct writing liquid wick structure.
7. The preparation method according to claim 6, characterized in that: In step 1, the upper and lower ceramic shell plates are made of alumina ceramic, and the middle ceramic frame is made of zirconia ceramic.
8. The preparation method according to claim 6, characterized in that: In step 2, during laser direct writing, firstly, horizontal microgrooves are written in the condensation zone, insulation zone, and evaporation zone of the ceramic frame, and then vertical microgrooves are written on the horizontal microgrooves in the condensation zone and evaporation zone to form a microgrooved liquid-absorbing core structure.
9. The preparation method according to claim 6, characterized in that: In step 3, when using sealant, apply sealant to the 1-3mm gap between the ceramic middle frame and the ceramic upper and lower shell plates, avoiding the injection port area.