A method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove

Abstract

The present invention discloses a method for processing a macro-micro integrated durable hydrophilic multi-level composite groove, comprising: S1, using mechanical forming or laser grooving to prepare a flow channel substrate with an open groove structure, and removing dust from the interior and surface of the groove; S2, covering the flow channel substrate with a thin film material; S3, covering the open groove structure covered with the thin film material with a transparent target material by pressing or vacuuming; S4, using a laser to transmit the transparent target material, texture deposition on the surface of the groove structure to form a durable transition layer, thereby forming a durable hydrophilic composite groove with a multi-level structure; S5, post-processing: placing the deposited combination obtained in S4 in an atmosphere box for baking, the purpose of which is to increase the bonding strength between the deposited particles and the open groove and improve wettability. The multi-level composite groove structure prepared by this method using a laser texture deposition process can improve the durability to liquid infiltration and wicking transport capacity, thereby improving the heat and mass transfer efficiency of the groove device.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic heat dissipation, and in particular to a method for processing a macro-micro integrated durable hydrophilic multi-level composite groove. Background Art

[0002] Microheat pipes have high heat transfer efficiency and fast thermal response, and are gradually becoming ideal heat dissipation components in fields such as microelectronics and chemical industry. Microheat pipes generally consist of three parts: an evaporation section, an insulation section, and a condensation section. The condensation section has a significant impact on its heat transfer performance. Condensation heat transfer is mainly used in refrigeration systems and is an important component of the heat exchange process. In essence, the gas is liquefied at the condensation wall, allowing heat to be quickly transferred to the vicinity of the substrate and carried away by the circulating water. Currently, condensation heat transfer has been widely used in fields such as power generation, seawater desalination, and chemical industry, and its application prospects are very broad. Therefore, if the efficiency of condensation heat transfer can be improved, problems such as energy consumption and environmental pollution will be greatly improved. In order to improve the durability of the grooves and enable the recycling of microheat pipes, the present invention uses a laser texture deposition process to deposit transparent target particles on the groove surface to form a durable transition layer. Pulsed laser deposition technology requires a near-axis donor and a vacuum environment. The deposition thickness is nanometers, the surface is nanostructured, and it utilizes the reflection of laser and particle beams. Laser texture deposition uses a light-transmitting material as a donor for transmission, does not require a vacuum environment, and can construct a cross-scale, integrated, designable structure from macro to nano. Pulsed laser deposition is a process in which a target material is ablated to sputter out a large number of complex micro-nano particles to form a plasma. The plasma expands directionally in a vacuum or background gas and reaches the substrate, forming products on the substrate. The presence of these particles sputtered out during the laser-induced explosion greatly reduces the quality of the film and makes the deposited surface uneven. The present invention uses laser texture deposition, and the deposited particle coating is more uniform. Under the conditions of high-temperature liquid circulation in a micro-heat pipe, the transparent target material deposited on the groove is more firmly deposited, the transport performance is better, and the durability of use is also better. Summary of the Invention

[0003] In recent years, with the increasing integration of electronic devices and their smaller and smaller sizes, the problem of heat dissipation due to high heat flux density has arisen. The cooling technology of electronic devices has become the key to the development of microelectronics technology, requiring it to have the characteristics of compactness, reliability, flexibility, high heat dissipation efficiency, etc., which poses new challenges for the application of modern heat transfer technology in the field of electronic cooling. Micro heat pipes are mainly composed of a tube shell, a working medium and a liquid wick, which are widely used in the field of heat dissipation of microelectronics. The current microelectronics industry is developing in the direction of lightweight and thinness, and traditional liquid wicks can no longer meet its size requirements. To this end, the present invention proposes a method for preparing a composite groove structure on the surface of a macro-micro integrated material.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove comprises the following steps:

[0006] S1. Prepare a flow channel substrate with an open groove structure by mechanical forming or laser grooving process, and remove dust inside and on the surface of the groove to meet the bonding strength requirements;

[0007] S2. A thin film material is covered on the flow channel substrate (carbon material film, diamond powder thin layer stacking film, graphene, graphene oxide film, carbon nanotube film, etc.);

[0008] S3, covering the transparent target material on the open groove structure of the covering film material by pressing or vacuuming;

[0009] S4, using a laser-transmitting transparent target material, laser texturing deposition is performed on the surface of the groove structure to form a durable transition layer, thereby forming a deposition combination of durable hydrophilic composite grooves with a multi-level structure;

[0010] S5. Post-processing: placing the deposited composite obtained in S4 in a vacuum at a temperature of 50 to 500° C. for 2 to 48 hours, in order to increase the bonding strength between the deposited particles and the open grooves and further improve the durability.

[0011] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove, the flow channel substrate is a high thermal conductivity alloy of Al, Cu, Mg, Ag, or a compound such as SiC, AlN, or a ceramic plate.

[0012] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove, the cross section of the groove structure is a geometric groove with a depth of 1 to 2 mm.

[0013] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove, the transparent target material contains SiO2, Al2O3 or other materials, and can transmit more than 93% of the laser energy.

[0014] Preferably, the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove adopts a laser-transmitting transparent target material to weave a "well" pattern on the surface of the groove structure.

[0015] Preferably, the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove is a macro-micro integrated groove, the geometric groove provides the main wicking ability, and the transparent target material micro-nanoparticles deposited on the groove surface can improve the wicking ability of the groove and absorb water against gravity.

[0016] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove, vacuum, air, Ar or N2 atmosphere can be used in S3.

[0017] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove, a vacuum cleaner is used in S1 to remove dust inside and on the surface of the groove to meet the bonding force requirement.

[0018] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove, in said S1, the laser grooving process is: using a short pulse laser with a laser wavelength of 1064nm, a laser pulse of 1ms~1fs, a repetition rate of 1Khz~10Ghz, and a single pulse energy of 1μJ~100mJ to groove the substrate.

[0019] Preferably, in the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove, in said S3, the process of laser texturing deposition is: using a short pulse laser with a laser wavelength of 1064nm, a laser pulse of 1ms~1fs, a repetition rate of 1Khz~10Ghz, and a single pulse energy of 1μJ~100mJ to deposit a durable transition layer on the groove structure.

[0020] Preferably, the above-mentioned method for processing a macro-micro integrated durable hydrophilic multi-level composite groove is post-processed as follows: the deposited combination obtained in S3 is placed in a vacuum oven at a temperature of 80°C and baked for 24 hours, in order to increase the bonding strength between the deposited particles and the open grooves and further improve the durability.

[0021] The processing method of the macro-micro integrated durable hydrophilic multi-level composite groove described in any one of the above items is used to prepare the condensation section of the micro heat pipe to improve its wicking ability and durability.

[0022] The present invention has the following beneficial effects: For micro-heat pipes, conventional chemical etching methods for wettable surfaces suffer from high pollution, high thermal resistance, and long processing cycles. However, a chemical-free laser texturing deposition process can be used to create integrated macro-micro grooves on metal plates. Furthermore, under conditions of long-term high temperature and liquid circulation, wettability is weakened, reducing the wicking ability of the grooves. The multi-level composite groove structure created using laser texturing deposition improves the wicking ability and durability of the grooves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the durable hydrophilic multi-stage composite groove of the present invention;

[0024] Figure 2 Schematic diagram of the laser texturing deposition process of the present invention.

[0025] In the figure: 1. Flow channel substrate, 2. Groove structure, 3. Durable transition layer, 4. Substrate, 5. Target material, 6. Laser, 7. Texture direction. DETAILED DESCRIPTION

[0026] In order to simplify the disclosure of this application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit this application, including manufacturing methods, material selection and processes.

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] Example 1

[0029] See also Figure 1-2 As shown, a method for processing a macro-micro integrated durable hydrophilic multi-level composite groove is processed by a laser texturing deposition process, comprising the following steps:

[0030] S1. Prepare a flow channel substrate 1 with an open groove structure 2 by a mechanical forming process or a laser grooving process, and use a vacuum cleaner to remove dust inside and on the surface of the groove to meet the bonding strength requirements;

[0031] Wherein: the flow channel substrate is a high thermal conductivity metal or ceramic plate such as Al, Cu, Mg, SiC, etc., and the cross section of the groove structure 2 is a geometric groove, preferably an inverted triangle groove;

[0032] S2. A thin film material is covered on the flow channel substrate (carbon material film, diamond powder thin layer stacking film, graphene, graphene oxide film, carbon nanotube film, etc.);

[0033] S3, using a compacting or vacuuming method to cover the transparent target material 5 on the open groove structure 2 covered with the thin film material, and providing different atmospheres (vacuum, air, Ar, N2) to improve the deposition effect of laser texturing deposition;

[0034] Among them: The laser texture deposition process is a physical deposition process. First, a transparent target material 5 (SiO2, Al2O3, etc.) is spread flat on the substrate, and a low-frequency pulsed laser 6 is focused on the surface of the transparent target material 5. Laser texture is performed on the transparent target material 5 through program control. The laser 6 transmits through the transparent target material 5 to sputter out particles and deposit a layer of particle coating on the substrate. Unlike pulsed laser deposition technology, pulsed laser deposition is a process in which a large number of complex micro-nano particles are sputtered out by ablating the target material 5 to form a plasma. The plasma reaches the substrate after directionally expanding in a vacuum or background gas, and forms products on the substrate. The presence of these particles sputtered out during the explosion caused by the laser 6 greatly reduces the quality of the film and makes the deposited surface uneven. The laser texture deposition process, which uses the laser texturing process, can make the deposition process more controllable and stable, and the combination of particles and substrate is more uniform. The transparent target material 5 (SiO2, Al2O3, etc.) has relatively stable chemical properties and has the characteristics of high fire resistance, high temperature resistance, small thermal expansion coefficient, high insulation, corrosion resistance, etc. It can protect the multi-level composite groove structure from corrosion under the harsh conditions of high temperature and liquid circulation, thereby improving the durability of transportation. The present invention requires depositing a durable coating of transparent target material 5 on the inner surface of the fine groove, and adopts pulsed laser deposition technology to sputter the target material 5 to deposit on the surface of the substrate 4. It is difficult for the target material 5 particles to be deposited on the inner wall of the fine groove, and the deposited particles have low bonding force. The present invention adopts a laser texturing deposition process, and the transparent target material 5 can be well deposited on the inner surface of the fine groove by program-controlled laser texturing pattern. The bonding force between the target material 5 particles and the substrate 4 can also be well controlled by program-controlled laser texturing enabling spacing;

[0035] S4, using laser 6 to transmit transparent target material 5, texture deposition along texture direction 7 on the surface of groove structure 2, forming durable transition layer 3; forming durable hydrophilic composite groove with multi-level structure;

[0036] The durable hydrophilic grooves of the multi-level composite grooves are composed of micro-nano-scale target material 5 particles and geometric grooves on the aluminum alloy flow channel substrate. The depth of the geometric groove structure is 1 to 2 mm, and its size is mainly controlled by the power of the laser 6 processing. The geometric grooves provide the main wicking ability, while the micro-nano-scale transparent target material 5 particles embedded in the flow channel substrate can assist in improving the wicking ability. Therefore, the multi-level composite structure has excellent anti-gravity water absorption ability. At the same time, the transparent target material 5 particles can also protect the wicking ability of the geometric grooves and improve the transport durability.

[0037] S5. Post-processing: The deposited composite obtained in S4 is placed in a vacuum oven and baked at 80° C. for 24 hours to improve the bonding strength between the deposited particles and the open grooves and further improve the durability.

[0038] Example 2

[0039] The present invention provides a method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove, which can be used in the heat dissipation process of a micro heat pipe. The specific steps are as follows:

[0040] (1) Forming a flow channel substrate 1 with an open groove structure 2:

[0041] The substrate was cleaned in deionized water and anhydrous ethanol using an ultrasonic cleaner. After cleaning, the substrate was naturally dried to obtain a clean substrate sample. A short-pulse laser with a laser wavelength of 1064nm, a laser pulse of 1ms to 1fs, a repetition rate of 1kHz to 10GHz, and a single pulse energy of 1μJ to 100mJ was used to groove the substrate. The substrate powder introduced into the grooves and on the surface by the machining was removed using a vacuum cleaner.

[0042] (2) A thin film material is coated on a flow channel substrate covered with the thin film material (carbon material film, diamond powder thin layer stacking film, graphene, graphene oxide film, carbon nanotube film, etc.);

[0043] (3) Technical preparations before laser texturing deposition process:

[0044] A block is pressed tightly against the transparent target 5 to cover the open groove 2 or a vacuum method is used to bring the transparent target 5 and the substrate into close contact. Different atmospheres (vacuum, air, Ar, N2) can be provided during the laser texture deposition process to improve the deposition effect of the laser texture deposition. During deposition, the entire block is covered, the environment is varied (vacuum, air, Ar, O2, etc.), the interface contact is diverse (it can be a gap of 300μm to 10μm, or it can be compacted under negative pressure), and a medium containing SiO2, Al2O3, etc. that can partially transmit the laser 6 is involved;

[0045] (4) Preparation of durable transition layer 3, and formation of durable hydrophilic composite grooves with multi-level structure:

[0046] A short-pulse laser with a wavelength of 1064nm, laser pulses of 1ms to 1fs, a repetition rate of 1kHz to 10GHz, and a single pulse energy of 1μJ to 100mJ is used to laser texture-deposit a durable transition layer 3 with a thickness of ≤2mm on an open groove structure. Simultaneously with the laser texture deposition, a multi-level durable hydrophilic composite groove is also prepared. The multi-level durable hydrophilic composite groove consists of two parts: a 1-2mm geometric deep groove structure that provides the main transport capacity, and smaller micro-nano transparent target material 5 particles embedded in the flow channel matrix that supplement the transport capacity. The two parts assist each other in significantly improving the wicking capacity and even exhibiting excellent anti-gravity water absorption performance.

[0047] (5) Post-treatment: The deposited composite obtained in step (4) is placed in a vacuum oven and baked at 80°C for 24 hours to improve the bonding strength between the deposited particles and the open grooves and further improve the durability.

[0048] In general, the advantages of the present invention are as follows:

[0049] 1. The processing method of a macro-micro integrated durable hydrophilic multi-level composite groove of the present invention adopts a laser grooving process to prepare a flow channel substrate 1 with a groove structure 2, and then adopts a laser texturing deposition process to deposit a durable transition layer on the open groove structure 2, and at the same time forms a multi-level structure composite groove. Compared with the mechanical processing method, the laser processing method has high material utilization rate, low cost and short manufacturing cycle. At the same time, the laser texturing deposition process has the characteristics of being green and pollution-free, low thermal resistance and short processing cycle compared with the chemical deposition method. Therefore, this method is suitable for mass production.

[0050] 2. The present invention adopts a durable multi-level structural composite groove, and prepares a multi-level composite structure with a micro-nano structure during the laser texturing deposition process. Due to the capillary action of the micro-nano structure on the groove, it is beneficial to improve the wicking and transport capacity of the micro heat pipe, thereby improving the heat dissipation capacity of the heat pipe. The use of a durable transition layer can make the micro heat pipe reusable, thereby improving the durability of the micro heat pipe.

[0051] Of course, the above are only preferred embodiments of the present invention and are not intended to limit the scope of use of the present invention. Therefore, any equivalent changes based on the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove, characterized by: The following steps are involved: S1. Prepare a flow channel substrate with an open groove structure by mechanical forming or laser grooving process, and remove dust inside and on the surface of the groove to meet the bonding strength requirements; S2, the film material covers the flow channel substrate; S3, covering the transparent target material on the open groove structure of the covering film material by pressing or vacuuming; S4, using a laser-transmitting transparent target material, laser texturing deposition is performed on the surface of the groove structure to form a transition layer, and the target material is removed to form a deposition combination of a durable hydrophilic composite groove with a multi-level structure; S5. Post-processing: placing the deposited composite obtained in S4 in a vacuum at a temperature of 50 to 500° C. for 2 to 48 hours, in order to increase the bonding strength between the deposited particles and the open grooves and further improve the durability.

2. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: The flow channel matrix is ​​a high thermal conductivity alloy of Al, Cu, Mg, Ag, or a SiC, AlN compound, or a ceramic plate.

3. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: The cross section of the groove structure is a geometric groove with a depth of 1 to 2 mm.

4. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: The transparent target material is a composite material that can transmit more than 93% of the laser.

5. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: Laser-transmitting transparent target material is used to weave patterns on the surface of the groove structure.

6. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 3, characterized in that: The composite groove is a macro-micro integrated groove, and the geometric groove provides the main wicking ability. The transparent target material micro-nanoparticles deposited on the groove surface improve the wicking ability of the groove and absorb water against gravity.

7. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: In the above-mentioned S3, a vacuum, air, Ar or N2 atmosphere can be used.

8. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: In the S1, post-processing is performed to remove dust inside and on the surface of the groove to meet the bonding strength requirement.

9. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to claim 1, characterized in that: In the above S4, the laser texture deposition process is: short pulse laser, wavelength of 700-3000nm, laser pulse 1ms-1fs, repetition rate 0.01Khz-10Ghz, single pulse energy 0.01μJ-100mJ.

10. The method for processing a macro-micro integrated durable hydrophilic multi-stage composite groove according to any one of claims 1 to 9 is used to prepare a condensation section of a micro heat pipe to improve its wicking capacity and durability.

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