Preparation method of thermal interface material based on multi-element filler confinement directional arrangement

Abstract

The invention relates to the technical field of micro-nano manufacturing, in particular to a thermal interface material preparation method based on multi-element filler confinement directional arrangement, and the method comprises the following steps: step 1, obtaining filler / matrix composite slurry; 2, removing bubbles in the composite slurry; step 3, preparing a chamber; 4, designing and preparing two structured electrodes; step 5, filling the composite slurry into the cavity; 6, applying an electric signal to directionally arrange the filler confinement in the composite slurry; 7, curing the composite slurry; 8, removing the cavity of the cured and formed composite slurry; and step 9, mounting the thermal interface material after cavity removal on the upper surface of the multi-chip module in an aligned manner. According to the invention, confinement filling and directional arrangement of the high-thermal-conductivity fibers and the high-thermal-conductivity nanosheets in the matrix are realized, and the prepared thermal interface material has the advantages of high energy efficiency, capability of directionally regulating and controlling heat flow, capability of realizing counterpoint heat dissipation of chips in any shape, and the like.

Description

Technical Field

[0001] The invention relates to the field of micro-nano manufacturing technology, and in particular to a method for preparing a thermal interface material based on confined and directional arrangement of multiple fillers. Background Art

[0002] With the rapid development of cutting-edge technologies such as artificial intelligence, 5G, and the Internet of Things, electronic components are accelerating their evolution towards high power, high integration, high frequency, and miniaturization, which poses new challenges to materials, design, and manufacturing processes. Driven by advanced packaging technology and heterogeneous integration, the three-dimensional integration and multi-chip assembly density of electronic devices have made significant breakthroughs. The simultaneous increase in their energy efficiency ratio and operating power consumption has made the uneven distribution of heat flow and the challenges of system-level heat dissipation more severe. The thermal stability of electronic devices has become a core factor affecting the reliability of high-efficiency semiconductor devices. Breaking through the thermal barrier plays a decisive role in achieving the continuous evolution of the next generation of intelligent systems. In recent years, the continuous development of chip integration technology and the complex and changeable use environment have made heat no longer concentrated on a single chip. The phenomenon of mutual heating between chips has become increasingly significant, making it difficult for each chip to reach its designed maximum power level, which brings greater challenges to thermal management. To address this issue, the current development of thermal interface materials faces two key technical requirements: on the one hand, it is necessary to prepare thermal interface materials that have both high thermal conductivity and can work effectively at low filling rates through the directional arrangement of fillers; on the other hand, it is necessary to develop confined thermal management materials suitable for multi-chip modules to effectively avoid thermal crosstalk between adjacent chips. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a method for preparing a thermal interface material based on confined and directional arrangement of multiple fillers.

[0004] The present invention is achieved by adopting the following technical solutions: A method for preparing a thermal interface material based on confined and directional arrangement of multiple fillers, the method comprising the following steps: Step 1: Disperse high thermal conductivity fibers and high thermal conductivity nanosheets as fillers in the matrix, and use high-speed centrifugal shearing and multi-band ultrasonic treatment to evenly disperse the fillers, and finally obtain a filler / matrix composite slurry without sedimentation and phase separation; Step 2: Place the composite slurry in a vacuum drying oven, start the vacuum pump, and slowly pump air to the target vacuum degree to completely remove the bubbles in the composite slurry; Step 3: Use 3D printing technology to prepare a chamber for holding the composite slurry; Step 4: According to the specific distribution position and heat source form of the chips in the multi-chip module, two structured electrodes are designed and prepared; Step Five: Place two structured electrodes in the chamber and above the chamber respectively, and use a pipette to fill the composite slurry into the chamber; Step Six: Apply an electrical signal to the composite slurry in the chamber to make the fillers in the composite slurry be confined and arranged directionally under the action of the electric field force; Step Seven: After the fillers are completely arranged, perform a curing treatment on the composite slurry; Step Eight: Remove the cured composite slurry from the chamber to obtain a thermal interface material containing fillers arranged neatly in a confined and directional manner; Step Nine: Use a chip mounter to align and mount the thermal interface material after removing the chamber on the upper surface of the multi-chip module, and detect the heat change during the heat dissipation process of the chip.

[0005] Further, in the said Step One, the high thermal conductivity fiber is a carbon-based fiber or a ceramic fiber or a metal fiber or a composite thermal conductivity fiber, and its diameter is between 150 nm and 1 μm; the high thermal conductivity nanosheet is a graphene nanosheet or a hexagonal boron nitride nanosheet or a silicon carbide nanosheet or a metal-based nanosheet or an MXene nanosheet, and its thickness is between 0.3 nm and 100 nm, and its lateral dimension is between 150 nm and 5 μm; the matrix is a photo-curable resin material or a thermo-curable resin material, and its viscosity is between 4×10 -3 Pa·s and 4×10 1 Pa·s.

[0006] Further, in the said Step One, the frequency of the multi-band ultrasonic treatment is 30 kHz to 100 kHz, and the time is 15 min to 40 min.

[0007] Further, in the said Step Two, the target vacuum degree is -0.09 MPa to -0.1 MPa, and the vacuum pumping time is 15 min to 30 min.

[0008] Further, in the said Step Four, the preparation process of the structured electrode is a lithography technique.

[0009] Further, in the said Step Five, the placement method of the two structured electrodes is parallel and opposite placement, and the structured electrode above the chamber is fixed on the lifting table.

[0010] Further, in the said Step Six, the applied electrical signal is a sinusoidal alternating current signal, its voltage is 60 V to 200 V, and its frequency is 0.1 MHz to 10 MHz.

[0011] Further, in the said Step Seven, the curing treatment method is photo-curing or thermo-curing; the light intensity of photo-curing is 100 mW / cm 2 ~500 mW / cm 2, the curing time is 2min~5min; the thermal curing temperature is 55℃~70℃, and the curing time is 15min~40min.

[0012] Furthermore, in the step eight, after the solidified composite slurry is decavified, it needs to be rinsed with flowing deionized water to remove the unreacted liquid matrix.

[0013] Furthermore, in step nine, the method of detecting heat changes is: using an infrared thermal imager to monitor the heat dissipation of the multi-chip module in real time during the cooling process, and recording the overall and local temperature changes of the thermal interface material.

[0014] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention utilizes the synergistic strengthening effect of fillers, and constructs a phase-confined domain directional heat conduction network in the matrix by using high thermal conductivity fiber and high thermal conductivity nanosheet filling units as the functional group of thermal interface materials. This design realizes the directional control of heat flow during the conduction process. Second, the present invention specifically designs and prepares structured electrodes according to the specific distribution position and heat source morphology of the chips in the multi-chip module, realizes the confined arrangement of high thermal conductivity fillers, effectively solves the problem of thermal crosstalk between adjacent chips in the multi-chip module, and forms a preparation method of a new type of thermal interface material with confined directional heat conduction function. Third, from the perspective of design and manufacturing principles, the present invention produces a dielectrophoresis effect on high thermal conductivity fibers / high thermal conductivity nanosheets through the flow / electric coupling field, so that high thermal conductivity fibers / high thermal conductivity nanosheets are arranged in a directional manner in the matrix, forming a new technology of filler confined filling and directional arrangement based on flow / electric field coupling constraints, which is expected to solve the cross-scale molding (nano-micro-macro) technical problems involved in the manufacturing process of multi-material systems.

[0015] The present invention realizes the confined filling and directional arrangement of high thermal conductivity fibers and high thermal conductivity nanosheets in a matrix. The thermal interface material prepared thereby has the advantages of high energy efficiency, directionally controllable heat flow, and alignable heat dissipation of chips of any shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of step one in the present invention.

[0017] Figure 2 It is a schematic diagram of step five in the present invention.

[0018] Figure 3 It is a schematic diagram of step six in the present invention.

[0019] Figure 4 It is a schematic diagram of step eight in the present invention.

[0020] Figure 5 It is a schematic diagram of step nine in the present invention.

[0021] In the figure: 1 - graphene nanosheets, 2 - silicon carbide fibers, 3 - polydimethylsiloxane, 4 - chamber, 5 - structured electrode, 6 - thermal interface material, 7 - multi-chip module. Specific embodiments

[0022] The present invention will be further described below in conjunction with embodiments and the accompanying drawings, but the protection scope of the present invention should not be limited thereby.

[0023] Referring to Figures 1 to 5 , a preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers, the method comprising the following steps: Step 1: Using silicon carbide fibers 2 with a diameter of 200 nm and a length of 4 μm and graphene nanosheets 1 with a thickness of 100 nm and a lateral size of 2 μm as fillers, using polydimethylsiloxane 3 as a matrix, placing the silicon carbide fibers 2 and graphene nanosheets 1 in a beaker containing polydimethylsiloxane 3, and ultrasonically oscillating for 30 min to uniformly disperse the fillers, obtaining a silicon carbide / graphene / polydimethylsiloxane composite slurry, as Figure 1 shown; Step 2: Placing the composite slurry in a vacuum drying oven, starting the vacuum pump, slowly pumping air to the target vacuum degree, and maintaining the vacuum state for 15 min to completely remove the bubbles in the composite slurry; Step 3: Using 3D printing technology to print a chamber 4 made of photosensitive resin with dimensions of 50 mm × 50 mm × 10 mm; Step 4: Designing the electrode layout according to the specific distribution position of the chips and the heat source form in the multi-chip module 7, and using lithography technology to prepare a structured electrode 5; Step 5: Placing two structured electrodes 5 parallel and opposite to each other in and above the chamber 4, and using a pipette to fill the composite slurry into the chamber 4, as Figure 2 shown; Step 6: Applying a sinusoidal alternating current signal with a voltage of 60 V and a frequency of 1 MHz between the two structured electrodes 5 to make the silicon carbide fibers 2 and graphene nanosheets 1 be confined and oriented arranged under the action of the electric field force, as Figure 3 shown; Step 7: After the silicon carbide fibers 2 and graphene nanosheets 1 are completely arranged, thermally curing the composite slurry, the thermal curing temperature is 60 °C, and the curing time is 20 min; Step 8: Demolding the cured composite slurry to obtain a thermal interface material 6 containing confined and oriented and neatly arranged fillers, and then rinsing the thermal interface material 6 with flowing deionized water to remove the unreacted liquid matrix, as Figure 4 shown; Step Nine: Use the vision alignment system of the chip mounter to position the upper surface of the multi-chip module 7; start the chip mounter, adsorb the thermal interface material 6 onto the suction nozzle, and mount it onto the upper surface of the multi-chip module 7 according to the preset path; after the mounting is completed, use an infrared thermal imager to monitor the heat dissipation of the multi-chip module 7 in real time during the cooling process, and record the overall and local temperature changes of the thermal interface material 6, as Figure 5 shown.

[0024] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers, characterized in that: The method comprises the following steps: Step 1: Dispersing high thermal conductivity fibers and high thermal conductivity nanosheets as fillers in a matrix, and using high-speed centrifugal shearing combined with multi-frequency ultrasonic treatment to make the fillers disperse uniformly, finally obtaining a filler / matrix composite slurry without sedimentation and phase separation; Step 2: Placing the composite slurry in a vacuum drying oven, starting the vacuum pump, and slowly evacuating to the target vacuum degree to completely remove the bubbles in the composite slurry; Step 3: Using 3D printing technology to prepare a chamber for holding the composite slurry; Step 4: According to the specific distribution positions and heat source forms of the chips in the multi-chip module, specifically designing and preparing two structured electrodes; Step 5: Placing the two structured electrodes in and above the chamber respectively, and using a pipette to fill the composite slurry into the chamber; Step 6: Applying an electric signal to the composite slurry in the chamber to make the fillers in the composite slurry arrange directionally within a limited range under the action of the electric field force; Step 7: After the fillers are completely arranged, performing a curing treatment on the composite slurry; Step 8: Demolding the cured composite slurry to obtain a thermal interface material containing fillers arranged neatly in a limited and directional manner; Step 9: Using a mounter to align and mount the demolded thermal interface material on the upper surface of the multi-chip module, and detecting the heat change during the heat dissipation process of the chips.

2. The preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the first step, the high thermal conductivity fiber is a carbon-based fiber, a ceramic fiber, a metal fiber or a composite thermal conductivity fiber, and its diameter ranges from 150 nm to 1 μm; the high thermal conductivity nanosheet is a graphene nanosheet, a hexagonal boron nitride nanosheet, a silicon carbide nanosheet, a metal-based nanosheet or an MXene nanosheet, and its thickness ranges from 0.3 nm to 100 nm, and its lateral dimension ranges from 150 nm to 5 μm; the matrix is a photocurable resin material or a thermocurable resin material, and its viscosity ranges from 4×10 -3 Pa·s to 4×10 1 Pa·s.

3. The preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 1, the frequency of the multi-frequency ultrasonic treatment is 30 kHz to 100 kHz, and the time is 15 min to 40 min.

4. A method for preparing a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 2, the target vacuum degree is -0.09 MPa to -0.1 MPa, and the vacuum pumping time is 15 min to 30 min.

5. The preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, wherein: In the said Step 4, the preparation process of the structured electrode is lithography technology.

6. The preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 5, the placement method of the two structured electrodes is to place them parallel and opposite to each other, and the structured electrode above the chamber is fixed on a lifting platform.

7. A preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 6, the applied electric signal is a sinusoidal alternating current signal, its voltage is 60 V to 200 V, and its frequency is 0.1 MHz to 10 MHz.

8. A preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the seventh step, the curing method is photocuring or thermal curing; the light intensity of photocuring is 100mW / cm 2 ~500mW / cm 2 , the curing time is 2min~5min; the temperature of thermal curing is 55°C~70°C, and the curing time is 15min~40min.

9. The preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 8, after demolding the cured composite slurry, it needs to be rinsed with flowing deionized water to remove the unreacted liquid matrix.

10. A preparation method of a thermal interface material based on the confined and oriented arrangement of multiple fillers according to claim 1, characterized in that: In the said Step 9, the way to detect the heat change is: using an infrared thermal imager to monitor the heat dissipation situation of the multi-chip module in real time during the cooling process, and recording the overall and local temperature changes of the thermal interface material.

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