High-thermal-conductivity flexible high-speed substrate and preparation method thereof
By using a mixture of clustered thermally conductive microparticles and fluororesin, a high thermal conductivity flexible high-speed substrate was prepared, which solved the problems of thermal conductivity and flexibility of existing copper-clad laminates when dissipating heat from high-power electronic components, and achieved efficient heat dissipation and low-cost production.
Patent Information
- Application Number
- CN202610067200.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-19
- Publication Date
- 2026-03-03
AI Technical Summary
Existing copper-clad laminates offer limited improvement in thermal conductivity in the thickness direction when dissipating heat from high-power electronic components. They are also characterized by excessive rigidity, insufficient ductility, complex manufacturing processes, and high costs.
A high thermal conductivity flexible high-speed substrate, including a copper foil layer and a base film layer, is prepared by mixing clustered thermally conductive microparticles formed by the aggregation of multiple primary microparticles with fluororesin and through extrusion and calendering processes.
It improves the thermal conductivity in the thickness direction of the substrate, enhances bending performance, reduces dielectric loss, simplifies the fabrication process, and reduces costs.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of copper clad laminate technology, specifically to a high thermal conductivity flexible high-speed substrate and its preparation method. Background Technology
[0002] Electronic components used in fields such as AI, 5G / 6G communications, optical modules, high-frequency radar, and new energy vehicles generate a lot of heat when operating at high power, and often need to be used with a high thermal conductivity substrate (copper clad laminate) to achieve effective heat dissipation in the thickness direction.
[0003] Some copper clad laminate (CCL) manufacturers are improving the thermal conductivity of their substrates by modifying substrate materials and optimizing manufacturing processes. However, existing improvement solutions still have at least one of the following drawbacks: First, the improvement in thermal conductivity in the thickness direction is limited, making it difficult to match the heat dissipation requirements of ultra-high power components; second, the substrate is too rigid and lacks sufficient ductility, making it impossible to achieve a stable flexible bending effect; and third, the manufacturing process is complex, resulting in high production costs.
[0004] Therefore, there is an urgent need in this field for a new type of high-speed substrate with high thermal conductivity (thickness direction), good bending performance, low signal transmission loss, simple process, and low cost. Summary of the Invention
[0005] One of the objectives of this invention is to overcome the deficiencies in the prior art and provide a high thermal conductivity flexible high-speed substrate with high dielectric constant, low dielectric loss, good bending performance, and high thermal conductivity in the thickness direction.
[0006] To solve the above technical problems, the present invention provides a high thermal conductivity flexible high-speed substrate, comprising a copper foil layer, a base film layer and a copper foil layer stacked sequentially, wherein the raw materials of the base film layer include fluororesin and thermally conductive particles, and the thermally conductive particles include clustered thermally conductive particles; The clustered thermally conductive particles are secondary particles formed by the aggregation of multiple primary particles.
[0007] A preferred technical solution is that the thermally conductive particles are selected from at least one of alumina, aluminum nitride, boehmite, silicon nitride, boron nitride, titanium dioxide, and silicon dioxide; Furthermore, the boron nitride is selected from at least one of hexagonal boron nitride and cubic boron nitride.
[0008] A preferred technical solution is that the average particle size of the clustered thermally conductive microparticles is 10~250μm; Furthermore, the thickness of the base film layer is 0.075~0.254 mm.
[0009] Furthermore, the average particle size of the clustered thermally conductive microparticles can be selected from point values of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, and 250 mm, or a range of two of the above point values as the maximum and minimum values. The thickness of the base film layer can be selected from point values of 0.075, 0.100, 0.106, 0.127, 0.152, 0.178, 0.203, 0.250, and 0.254 mm, or a range of two of the above point values as the maximum and minimum values.
[0010] A preferred technical solution is that the primary particles are sheet-like particles, the average particle size of the primary particles is 1~30μm, and the average aspect ratio of the primary particles is 10~500; Furthermore, the average particle size of the primary particles is 3~7 μm.
[0011] Furthermore, the average particle size of the primary particles can be selected as a point value of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 30 μm, or an interval value between the two points mentioned above as the maximum and minimum values. The average diameter-to-thickness ratio of the primary particles can be selected as a point value of 10, 20, 50, 70, 90, 100, 200, 300, 400, or 500, or an interval value between the two points mentioned above as the maximum and minimum values.
[0012] A preferred technical solution is that, by weight, the base film comprises: 35-55 parts of fluororesin and 45-65 parts of thermally conductive microparticles.
[0013] Furthermore, the number of parts of the fluororesin can be selected as 35, 40, 45, 50, 55 points or a range of the above two points as the maximum and minimum values, and the number of parts of the thermally conductive particles can be selected as 45, 50, 55, 60, 65 points or a range of the above two points as the maximum and minimum values.
[0014] Furthermore, the thermally conductive particles are obtained by mixing clustered thermally conductive microparticles and silica microparticles in a mass ratio of (7.32~49):1.
[0015] Furthermore, the mass ratio of clustered thermally conductive particles to silica particles can be selected as point values of 7.33:1, 9:1, 12:1, 24:1, 49:1, or the above two point values as a range of maximum and minimum values.
[0016] The second objective of this invention is to provide a method for preparing a highly thermally conductive flexible high-speed substrate, comprising the following steps: S10: Fluoropolymer, thermally conductive microparticles and extrusion aid are mixed and cured to obtain a paste-like cured material. The cured material is then formed into blanks, extruded into sheets, calendered and baked to obtain a base film. S20: Stack steel plate, copper pad, copper foil, at least one layer of base film, copper foil, copper pad, and steel plate; S30: High thermal conductivity flexible high-speed substrate obtained by hot pressing and sintering.
[0017] The preferred technical solution is that the mass ratio of the fluororesin to the extrusion aid is (2~14):1.
[0018] Furthermore, the mass ratio of the fluororesin to the extrusion aid can be selected as a point value of 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, or 14:1, or a range of the above two point values as the maximum and minimum values.
[0019] The preferred technical solution is that the extrusion pressure in the extrusion sheeting step is 5~15 MPa; Furthermore, the extrusion temperature for the extrusion sheeting step is 50~100℃.
[0020] Furthermore, the extrusion pressure in the extrusion sheeting step can be selected from a point value of 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, or 15 MPa, or a range of two of the above points as the maximum and minimum values. The extrusion temperature in the extrusion sheeting step can be selected from a point value of 50℃, 60℃, 70℃, 80℃, 90℃, or 100℃, or a range of two of the above points as the maximum and minimum values.
[0021] The preferred technical solution is that the calendering temperature of the calendering step is 50~100℃.
[0022] Furthermore, the calendering temperature in the calendering step can be selected as a point value of 50℃, 60℃, 70℃, 80℃, 90℃, or 100℃, or a range of two of the above point values as the maximum and minimum values.
[0023] The preferred technical solution is that the product of the extrusion sheeting step is a substrate with a thickness of T1, and the product of the calendering step is a calendered sheet with a thickness of T2, where T1 / T2≥4.
[0024] The advantages and beneficial effects of this invention are as follows: The high thermal conductivity flexible high-speed substrate of this invention has a reasonable structure, high dielectric constant, low dielectric loss, and excellent thermal conductivity in the thickness direction; By selecting clustered thermally conductive particles as thermally conductive fillers, the thermal conductivity in the thickness direction of the substrate is improved. Fluoropolymer resin was selected as the substrate resin, resulting in good bending performance of the substrate. The substrate is prepared by extrusion and calendering processes, which improves the thermal conductivity in the thickness direction of the substrate. Detailed Implementation
[0025] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.
[0026] Clustered thermally conductive particles Clustered thermally conductive particles are secondary particles formed by the aggregation of multiple primary particles. Among them, primary particles refer to micron-sized particles, and the morphology of primary particles can be one-dimensional fibrous and / or two-dimensional sheet-like.
[0027] raw material: Clustered boron nitride microparticles: with an average particle size of 30 μm, formed by the aggregation of plate-like boron nitride microparticles (hexagonal boron nitride) with an average particle size of 4 μm and an average aspect ratio of 100; Silica microparticles: average particle size 5μm.
[0028] Examples and Comparative Examples 1. Examples 1-4 regarding the proportion of thermally conductive particles in the base film raw material 1.1. Preparation process of Example 1: S1: Weigh 50 parts by weight of polytetrafluoroethylene powder and 50 parts by weight of thermally conductive microparticles (silane coupling agent modified clustered boron nitride microparticles), and mix them 5 times using an airflow mixing method, each time for 5 minutes.
[0029] S2: Add 10 parts of extrusion aid to the mixed material, stir the aid evenly by physical mixing method, and mature for 12 hours to obtain a paste-like mixture; S3: Place the mixture into a molding die and press it into a blank. The blanking pressure is 8MPa to obtain the blank. S4: The preform is extruded from the flat die head into a sheet, and then wound up with a winding machine. The extrusion pressure is 10MPa, the extrusion speed is 2.5mm / min, and the extrusion temperature is 80℃ to obtain a roll material (base sheet) with a thickness of 3mm. S4: Unroll the roll and place it into a twin-roll calender. Adjust the distance between the twin rolls to 140μm and the calendering temperature to 80℃. Use a winding machine to wind it up to obtain a base film (calendered sheet) with a thickness of 140μm. S5: Place the base film obtained in S4 into a mesh bag oven for baking (to remove the extrusion aid), and then roll it up. The maximum baking temperature is 310℃ and the baking time is 30min. S6: Unfold the base film obtained in S5, cut it, and then stack the steel plate, 35μm thick copper pad, 35μm thick copper foil, base film, 35μm thick copper foil, 35μm thick copper pad, and steel plate in sequence. Then place it in a vacuum laminator for hot pressing and sintering. The hot pressing and sintering temperature is 385℃, the holding time is 120min, and the hot pressing and sintering pressure is 5MPa. Finally, peel off the steel plate and copper pad to obtain a high thermal conductivity flexible high-speed substrate (the thickness of the base film layer between the two copper foil layers is 0.106mm).
[0030] Examples 2, 3, and 4 employed the same preparation process as Example 1. The proportions of polytetrafluoroethylene powder, modified clustered boron nitride microparticles, and extrusion aid in the base film raw materials of Examples 1-4, by weight, are shown in the table below:
[0031] 1.2. Detection methods of Examples 1-4 The dielectric constant and loss factor of copper clad laminates shall be determined in accordance with GB / T 12636-1990; the thermal conductivity in the thickness direction of copper clad laminates shall be determined in accordance with GB / T 22588-2008.
[0032] 1.3. Performance test results and analysis of the samples in Examples 1-4
[0033] The loss factor for Examples 1-3 is 0.0006, and the loss factor for Example 4 is 0.0009.
[0034] The performance test results of the samples in Examples 1-3 show that: appropriately increasing the proportion of thermally conductive particles in the base film raw material is beneficial to improving the dielectric constant and thermal conductivity in the thickness direction of the substrate.
[0035] Based on Example 3, the dielectric constant and thermal conductivity of Example 4 decreased, while the loss factor increased. The possible reason is that the proportion of thermally conductive particles in the base film raw material is too high, making it easy for pores to appear inside the produced base film.
[0036] 2. Examples 3, 5, 6, 7, 8, and 9 regarding the proportion of clustered boron nitride microparticles in the thermally conductive particles. 2.1. The preparation process of Examples 5, 6, 7, 8, and 9 is based on Example 3. The thermally conductive particles in Examples 5, 6, 7, 8, and 9 are a mixture of clustered boron nitride microparticles (modified with silane coupling agent) and silica microparticles (modified with silane coupling agent). The mass ratio of clustered boron nitride microparticles to silica microparticles in the thermally conductive particles of Examples 5, 6, 7, 8, and 9 is shown in the table below:
[0037] 2.2. Detection methods for Examples 3, 5, 6, 7, 8, and 9 Peel strength of copper-clad laminates determined according to GB / T 4722-2017 2.3. Performance test results and analysis of samples from Examples 3, 5, 6, 7, 8, and 9
[0038] The performance test results of Examples 3, 5, 6, 7, 8, and 9 show that the dielectric constant and peel strength of the copper-clad laminate are positively correlated with the proportion of silicon dioxide particles in the thermally conductive microparticles. The thermal conductivity of the copper-clad laminate is positively correlated with the proportion of clustered boron nitride particles in the thermally conductive microparticles. When thermal conductivity in the thickness direction is given priority, Example 5 should be selected; when dielectric constant and peel strength are given priority, Example 9 should be selected.
[0039] 3. Examples 3, Comparative Example 1, and Comparative Example 2 regarding the morphology of thermally conductive microparticles in the base film raw material. 3.1. The preparation processes of Comparative Example 1 and Comparative Example 2 are both based on Example 3. The difference is that the thermally conductive microparticles used in Comparative Example 1 are sheet-like boron nitride microparticles with an average particle size of 25 μm (average aspect ratio of 200), while the thermally conductive microparticles used in Comparative Example 2 are spherical boron nitride microparticles with an average particle size of 25 μm.
[0040] 3.2. Performance test results and analysis of the samples from Example 3, Comparative Example 1, and Comparative Example 2
[0041] The performance test results of the samples in Example 3, Comparative Example 1, and Comparative Example 2 show that the preferred morphology of the thermally conductive microparticles is beneficial to improving the thermal conductivity in the thickness direction of the substrate.
[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A high thermal conductivity flexible high-speed substrate, comprising a copper foil layer, a base film layer, and a copper foil layer stacked sequentially, wherein the base film layer is made of fluororesin and thermally conductive microparticles, characterized in that, The thermally conductive particles include clustered thermally conductive particles; The clustered thermally conductive particles are secondary particles formed by the aggregation of multiple primary particles.
2. The high thermal conductivity flexible high-speed substrate according to claim 1, characterized in that, The thermally conductive particles are selected from at least one of alumina, aluminum nitride, boehmite, silicon nitride, boron nitride, titanium dioxide, and silicon dioxide. Furthermore, the boron nitride is selected from at least one of hexagonal boron nitride and cubic boron nitride.
3. The high thermal conductivity flexible high-speed substrate according to claim 1, characterized in that, The average particle size of the clustered thermally conductive microparticles is 10~250μm; Furthermore, the thickness of the base film layer is 0.075~0.254 mm.
4. The high thermal conductivity flexible high-speed substrate according to claim 3, characterized in that, The primary particles are sheet-like particles, with an average particle size of 1~30μm and an average aspect ratio of 10~500. Furthermore, the average particle size of the primary particles is 3~7 μm.
5. The high thermal conductivity flexible high-speed substrate according to claim 1, characterized in that, The base film comprises, by weight, 35-55 parts of fluororesin and 45-65 parts of thermally conductive microparticles.
6. A method for fabricating a high thermal conductivity flexible high-speed substrate, characterized in that, Based on the high thermal conductivity flexible high-speed substrate according to any one of claims 1 to 5, the method includes the following steps: S10: Fluoropolymer, thermally conductive microparticles and extrusion aid are mixed and cured to obtain a paste-like cured material. The cured material is then formed into blanks, extruded into sheets, calendered and baked to obtain a base film. S20: Stack steel plate, copper pad, copper foil, at least one layer of base film, copper foil, copper pad, and steel plate; S30: High thermal conductivity flexible high-speed substrate obtained by hot pressing and sintering.
7. The method for preparing a high thermal conductivity flexible high-speed substrate according to claim 6, characterized in that, The mass ratio of the fluororesin to the extrusion aid is (2~14):
1.
8. The method for preparing a high thermal conductivity flexible high-speed substrate according to claim 6, characterized in that, The extrusion pressure for the extrusion sheeting step is 5~15 MPa; Furthermore, the extrusion temperature for the extrusion sheeting step is 50~100℃.
9. The method for preparing a high thermal conductivity flexible high-speed substrate according to claim 6, characterized in that, The calendering temperature for the calendering step is 50~100℃.
10. The method for preparing a high thermal conductivity flexible high-speed substrate according to claim 6, characterized in that, The product of the extrusion step is a substrate with a thickness of T1, and the product of the calendering step is a calendered sheet with a thickness of T2, where T1 / T2≥4.