A high-thermal-conductivity aluminum-based copper-clad plate laminating forming method based on resin rheological characteristics

Abstract

The application discloses a high-thermal-conductivity aluminum-based copper-clad plate laminating forming method based on resin rheological characteristics, and belongs to the technical field of copper-clad plate manufacturing. The application comprises the following steps: carrying out composite interface treatment on an aluminum plate, preparing a three-gradient thermal-conductivity filler compound adhesive film, adopting a five-stage rheological matching laminating process, setting a controllable excess adhesive flow guide area, gradient cooling and stepped pressure relief shaping, and the like. The application realizes ordered filling of resin through double reinforcement of interface physical anchoring and chemical bonding, sectional drying and rheological precise regulation of the adhesive film, and five-stage laminating, effectively solves technical problems of low thermal-conductivity efficiency, weak interface combination, easy delamination, high defect rate, large warpage and the like of the existing aluminum-based copper-clad plate, and significantly improves the product thermal-conductivity coefficient, peeling strength, dimensional stability and insulation reliability. The application has the characteristics of process stability, suitability for mass production, excellent comprehensive performance and the like, and can be widely applied to high-reliability heat dissipation scenes such as LED, new energy automobile electric control and 5G communication.

Description

Technical Field

[0001] This invention mainly relates to the field of copper clad laminate manufacturing technology, specifically a method for laminating high thermal conductivity aluminum-based copper clad laminates based on the rheological properties of resin. Background Technology

[0002] With the increasing demands for heat dissipation performance and reliability in electronic devices from fields such as LED lighting, new energy vehicle electronic control, and 5G communication, the market demand for high thermal conductivity aluminum-based copper clad laminates (CCLs) continues to grow as a core heat dissipation substrate. The performance of aluminum-based CCLs mainly depends on thermal conductivity, interfacial adhesion, dimensional stability, and defect control, and these properties are closely related to lamination processes, raw material formulations, and interface treatment technologies.

[0003] There are already various preparation methods for aluminum-based copper clad laminates in the prior art. For example, Chinese invention patent CN115122721B discloses a high thermal conductivity aluminum-based copper clad laminate and its preparation method. This method uses an epoxy resin composition as an insulating layer and selects spherical aluminum oxide with two particle sizes of 10μm and 40μm in a weight ratio of 2:0.5 as filler. After simple mixing, it is laminated. However, this technology only uses a two-stage particle size filler compound, which fails to form a continuous and dense thermal conductive network, limiting the improvement of thermal conductivity (the highest measured value is 3.15 W / (m·K)). Furthermore, the aluminum plate surface is not subjected to targeted interface strengthening treatment, relying solely on the natural bonding between the resin and the aluminum matrix. The original text states a peel strength of 1.9 N / mm, but considering industry practice, this should be considered an error in the description. The reasonable range should be 0.19 N / mm, which is approximately 1.9 N / cm after conversion. Under long-term thermal shock, interlayer separation is likely to occur. At the same time, the lamination process is not matched with the resin rheological properties, and conventional constant temperature pressing is used, which easily leads to problems such as filler agglomeration and uneven glue overflow.

[0004] Another related prior art is disclosed in Chinese invention patent CN113597099B, which discloses a method for controlling warpage of aluminum-based hybrid laminate and a PCB board. This technology improves warpage by optimizing the thickness ratio of the aluminum base to the core board dielectric layer (≥10:1), preheating and pressing the aluminum base, and leveling treatment after lamination. The lamination process uses a fixed pressure of 30-40 kg / cm². 2 The 200℃ constant temperature pressing was not segmented for temperature and pressure control, and the synergistic improvement of thermal conductivity and interfacial bonding was not considered. The single interfacial treatment method of belt grinding and chemical roughening resulted in limited physical anchoring effect and weak chemical bonding. The film formulation did not have a gradient design for thermally conductive fillers, resulting in discontinuous thermal conduction paths. The resin flow was difficult to control precisely, leading to a high product defect rate and failing to meet the requirements of high-end electronic equipment for low defects and high reliability.

[0005] In summary, existing technologies generally suffer from the following technical shortcomings: First, thermally conductive fillers are mostly two-stage or single-size composites, making it difficult to form a seamless, continuous thermally conductive network, resulting in limited thermal conductivity. Second, the aluminum plate interface treatment methods are simplistic, lacking the synergistic reinforcement of physical anchoring and chemical bonding, leading to weak interfacial adhesion and poor reliability. Third, the lamination process does not match the full-process characteristics of the resin, resulting in frequent defects such as uneven filler distribution, glue overflow, glue shortage, and board warping. Fourth, the viscosity of the adhesive film preparation system is not effectively controlled, easily leading to filler agglomeration. These problems severely restrict the application of high thermal conductivity aluminum-based copper clad laminates in high-end electronic devices. Therefore, developing a lamination method for aluminum-based copper clad laminates that balances high thermal conductivity, strong adhesion, low defects, and stable dimensions has become an urgent technical need to be addressed in this field. Summary of the Invention

[0006] This invention addresses the problem of overly simplistic solutions in existing technologies by providing a significantly different approach. It primarily offers a high thermal conductivity aluminum-based copper-clad laminate lamination method based on resin rheological properties. This method solves the technical problems mentioned in the background section, such as insufficient thermally conductive filler layering leading to discontinuous thermal networks, weak bonding and poor reliability due to simplistic interface treatment, high defect rates caused by lamination processes not matching the full rheological process of the resin, and filler agglomeration due to uncontrolled film viscosity.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] A method for laminating high thermal conductivity aluminum-based copper-clad laminates based on resin rheological properties, characterized by the following steps:

[0009] S1. Raw material preparation: Prepare aluminum plates, high thermal conductivity rheological adhesive films and copper foils respectively. The aluminum plates are subjected to four interface treatments in sequence: alkaline washing and degreasing, micro-etching treatment, low temperature plasma activation and short pulse laser directional roughening. The copper foils are subjected to dust removal and oxidation surface activation treatment.

[0010] S2. Stacking arrangement: Stack the supporting steel plate, lower buffer pad, copper foil, high thermal conductivity rheological adhesive film, aluminum plate, upper buffer pad, and steel cover in sequence, and reserve a controllable overflow guide area at the edge;

[0011] S3, Five-stage rheological matching lamination: Vacuum hot pressing is performed on the carrier plate assembly after the stacked arrangement is completed. The control is divided into five stages, namely the melting stage, rheological filling stage, gel lock stage, curing stage and gradient shaping stage.

[0012] S4. Post-processing: After lamination, the laminated components are cooled, separated by a tooling, the buffer pad is peeled off, and cut to obtain a high thermal conductivity aluminum-based copper-clad laminate.

[0013] This invention employs a four-step composite interface treatment on an aluminum plate to form a dual-strengthened interface through physical anchoring and chemical bonding; copper foil activation enhances interfacial adhesion; a controllable resin overflow channel ensures uniform resin flow; and a five-stage rheological matching lamination process dynamically matches the resin rheological behavior with lamination parameters, achieving uniform resin filling, uniform filler distribution, full curing, and low-stress shaping. Finally, post-processing yields a high thermal conductivity aluminum-based copper-clad laminate with stable dimensions, few defects, and uniform performance. In summary, this invention achieves integrated molding of high thermal conductivity, high adhesion, low defects, and low warpage aluminum-based copper-clad laminates, solving the problems of poor thermal conductivity, weak adhesion, easy delamination, easy warpage, and high defect rate in existing technologies.

[0014] Furthermore, the aluminum plate undergoes interface treatment in the following four steps:

[0015] (1) Alkaline washing and degreasing: Immerse the aluminum plate in an alkaline degreasing solution of sodium hydroxide at a temperature of 50-60℃ and a mass concentration of 3%-8% for 3-8 minutes to remove oil stains, fingerprints, dust and natural loose oxide layer from the surface of the aluminum plate; after taking it out, rinse it with running deionized water 2-3 times to wash away the residual alkali solution, and then dry it in an oven at 80-100℃ for 5-10 minutes to ensure that the plate surface is dry, free of watermarks and residual alkali;

[0016] (2) Micro-etching treatment: The aluminum plate after alkaline washing and degreasing is immersed in the micro-etching solution for micro-etching. The micro-etching solution consists of: 10% to 15% sulfuric acid, 3% to 5% hydrogen peroxide and the remainder deionized water; the micro-etching temperature is 25 to 35℃ and the micro-etching time is 30 to 60s; through micro-etching, a uniform, continuous, micron-level pit structure with a depth of 0.5 to 1.5μm is formed on the surface of the aluminum plate, which improves the physical anchoring ability between the adhesive film and the aluminum plate; after micro-etching, it is immediately rinsed thoroughly with deionized water and dried with nitrogen gas;

[0017] (3) Low-temperature plasma activation: The micro-etched aluminum plate is sent into a low-temperature vacuum plasma treatment machine with a vacuum degree of -60 to -80 kPa; the working gas is a mixture of argon and oxygen with a volume ratio of 3:1 and a gas flow rate of 20 to 50 sccm; the treatment power is 200 to 400 W; and the treatment time is 60 to 120 s. Through plasma bombardment, micro-contaminants on the surface of the aluminum plate are removed, the surface energy is increased to more than 50 mN / m, and active groups such as hydroxyl and carboxyl groups are generated on the surface, which significantly enhances the chemical bonding ability between the resin and the aluminum plate.

[0018] (4) Short-pulse laser directional roughening: A short-pulse fiber laser is used to perform directional trench roughening on the aluminum plate after low-temperature plasma activation. The laser wavelength is 1064nm, the pulse width is 20-100ns, and the laser power is 10-30W. The scanning speed is 1500-2500mm / s, the scanning line spacing is 50-100μm, and the scanning path is a parallel unidirectional trench. Through laser directional etching, continuous trenches with uniform spacing are formed on the surface of the aluminum plate, and the surface roughness Ra of the aluminum plate is finally controlled at 1.0-3.0μm, forming a three-dimensional interlocking interface of physical anchoring and chemical bonding.

[0019] This invention removes surface oil and oxide layers through alkaline washing, improving interface cleanliness; micro-etching creates micron-level pits, enhancing the mechanical bonding between the adhesive film and the aluminum plate; low-temperature plasma activation removes micro-contaminants, increases surface energy, and generates active groups, strengthening chemical bonding; short-pulse laser directional roughening constructs a uniform groove structure, forming a three-dimensional interlocking interface. This achieves dual strengthening of the aluminum plate interface through physical anchoring and chemical bonding, significantly improving peel strength, enhancing thermal shock reliability, and reducing delamination.

[0020] Further, in step S1, the raw materials of the high thermal conductivity rheological adhesive film include, by weight:

[0021] Resin matrix: 60-80 parts epoxy resin, 10-15 parts phenolic resin, 5-10 parts rubber toughening agent;

[0022] Thermally conductive filler: 30-40 parts of large-particle-size spherical alumina, 15-20 parts of medium-particle-size spherical alumina, and 8-15 parts of nano-boron nitride; wherein the particle size of the large-particle-size spherical alumina is 10-20 μm, the particle size of the medium-particle-size spherical alumina is 3-8 μm, and the particle size of the nano-boron nitride is 50-200 nm;

[0023] Functional additives: 1-3 parts silane coupling agent, 3-6 parts composite curing agent, and 0.5-2 parts rheology modifier.

[0024] In this invention, epoxy resin provides the main adhesive and insulating properties; phenolic resin improves toughness and film-forming properties; rubber toughening agent reduces internal stress and enhances impact resistance; large / medium / nano-graded thermally conductive fillers form a continuous and dense thermally conductive network; silane coupling agent improves filler dispersibility and interfacial bonding; composite curing agent ensures complete cross-linking; and rheology modifier stabilizes the system viscosity and prevents filler sedimentation and agglomeration. This results in a film with high thermal conductivity, high toughness, low viscosity fluctuation, easy coating, and easy lamination. Consequently, the high thermal conductivity rheological film exhibits high thermal conductivity, good insulation, uniform adhesive layer, and is free of agglomeration and bubbles.

[0025] Furthermore, the preparation method of the high thermal conductivity rheological adhesive film is as follows:

[0026] (1) Premixing and prepolymerizing resin matrix

[0027] Add solvent, such as acetone or ethyl acetate, to a constant-temperature high-speed dispersion reactor, in an amount of 30-50 parts; turn on the stirrer at a speed of 300-500 r / min; then add epoxy resin, phenolic resin, and rubber toughening agent in sequence; heat to 50-65℃, keep warm and stir for 30-60 min to completely dissolve the resin and achieve uniform prepolymerization, thus obtaining a transparent and uniform matrix resin liquid.

[0028] (2) Surface modification and dispersion of thermally conductive fillers

[0029] Add silane coupling agent to the matrix resin solution and stir for 10-15 min; then add thermally conductive fillers in sequence: large-particle-size spherical alumina (10-20 μm), medium-particle-size spherical alumina (3-8 μm), and nano-boron nitride (50-200 nm); after each filler is added, stir and disperse for 8-12 min to prevent agglomeration; then add rheology modifier and disperse at high speed of 800-1200 r / min for 20-30 min to ensure uniform dispersion of fillers and stable system viscosity within the optimal rheological range of 500-1500 Pa·s.

[0030] (3) Adding the curing system to the adhesive solution

[0031] Reduce the rotation speed to 250-450 r / min and add the composite curing agent, which is a mixture of amine curing agent and acid anhydride curing agent in a mass ratio of 1:1; continue stirring for 15-20 min to mix thoroughly; then filter with a 100-200 mesh filter to remove agglomerated particles and impurities to obtain a high thermal conductivity rheological adhesive.

[0032] (4) Coating and segmented drying of adhesive film

[0033] A high thermal conductivity rheological adhesive liquid is coated onto a PET release film using a precision coating machine at a speed of 3–8 m / min, resulting in an adhesive layer thickness of 80–150 μm. The film is then dried in stages in an oven. The first zone is controlled at 50–80℃, primarily to dry the solvent; the second zone is controlled at 90–120℃, primarily to initially remove tack; and the third zone is controlled at 130–160℃, primarily to achieve semi-curing and shaping. After drying, the film is wound up to obtain a high thermal conductivity rheological adhesive film, which can be directly used for lamination.

[0034] This invention ensures complete dissolution and prepolymerization of the resin through resin premixing; prevents agglomeration by adding fillers in stages; achieves uniform distribution of fillers through high-speed dispersion; enables gradual solvent evaporation through staged drying to avoid bubble formation; and achieves optimal B-stage state through low-temperature solvent removal, medium-temperature de-adhesion, and high-temperature semi-curing. This results in a high thermal conductivity adhesive film that is bubble-free, pinhole-free, uniform in thickness, and exhibits stable rheological properties. During lamination, it demonstrates good filling properties, prevents overflow and shortfall, and maintains tight interfacial bonding.

[0035] Furthermore, the copper foil undergoes dust removal and oxidation surface activation treatment specifically as follows:

[0036] (1) Dust removal treatment on both sides of copper foil

[0037] Select rolled or electrolytic copper foil with a thickness of 18–70 μm. Load the copper foil into the unwinding station of the coating machine and pass it through a three-stage dust removal unit: first, using 80–120 g / m² dust removal material. 2 The copper foil is treated with adhesive paper rollers to remove dust, lint, and debris from both the top and bottom surfaces. Then, a high-pressure ion air gun (0.2–0.4 MPa, 10–20 mm from the copper foil surface) is used to blow away any remaining micro-dust. Finally, a clean, non-woven cloth is used to gently wipe the copper foil surface to ensure there are no visible contaminants, oil stains, or fingerprints. This ensures a clean copper foil surface and prevents bubbles, white spots, and interface defects from forming during lamination.

[0038] (2) Activation treatment of copper foil oxide surface

[0039] The dust-removed copper foil, with its oxide surface facing upwards, is fed into a low-temperature plasma activation machine for surface activation. The working gas is a mixture of argon and oxygen in a 4:1 volume ratio, with a gas flow rate of 30–60 sccm; a vacuum level of -50–-70 kPa; an activation power of 100–300 W; a processing speed of 1.5–3.0 m / min; and a processing time of 30–90 s. After activation, the surface energy of the copper foil increases to over 55 mN / m; active groups such as hydroxyl and carbonyl groups are generated on the copper foil surface; and the micro-roughness of the oxide surface is slightly improved, forming strong chemical bonds with the high thermal conductivity rheological adhesive film.

[0040] (3) Temporary storage and protection of activated copper foil

[0041] Immediately place the activated copper foil into a dust-free, sealed channel and complete the lamination and bonding with the adhesive film within 10 minutes to avoid secondary surface contamination. Do not touch the activated surface of the copper foil with your hands to prevent oil stains and fingerprints from reducing the bonding strength.

[0042] This invention removes dust, oil, and debris from the surface of copper foil through a three-stage dust removal process; plasma activation enhances the surface energy of the copper foil and generates active groups such as hydroxyl and carbonyl groups, enabling the copper foil to form strong chemical bonds with the adhesive film. This process purifies the copper foil surface, improves interfacial reactivity, and ultimately significantly improves the peel strength of the copper foil, resulting in lamination without bubbles, white spots, or delamination.

[0043] Further, step S2 specifically involves: sequentially stacking the supporting steel plate, lower buffer pad, copper foil (oxidized side down), high thermal conductivity rheological adhesive film, aluminum plate, upper buffer pad, and steel cover; leaving a 0.5-1.0mm controllable overflow guide area at the edge of the stack to ensure uniform resin flow.

[0044] The copper foil of this invention has higher oxidation surface activity, facing downwards and directly contacting the adhesive film, which maximizes interfacial adhesion and ensures the strongest interfacial bond between the copper foil and the adhesive film. A 0.5–1.0 mm flow guide zone provides adequate space for resin flow, allowing excess resin to drain in an orderly manner and preventing localized resin buildup or shortages. This results in a uniform board edge, free from resin shortages, overflow, white spots, and voids.

[0045] Further, step S3 specifically involves: feeding the stacked carrier plate assembly into a high-temperature vacuum multilayer hot press, closing the chamber door, and starting the vacuum system. Following a preset five-stage rheological matching program, the pressurization, vacuuming, heat and pressure holding, gradient cooling, and step-by-step depressurization processes are automatically completed to achieve the lamination molding of the high thermal conductivity aluminum-based copper-clad laminate. The control parameters for each stage are as follows:

[0046] (1) Melting stage: temperature is 80~120℃, pressure is 0.2~0.5MPa, vacuum degree is -60~-80kPa, and heat and pressure are maintained for 10~20min. This allows the resin to melt completely, reduces the initial viscosity, and eliminates local agglomeration.

[0047] (2) Rheological filling stage: temperature is 130~170℃, pressure is 0.8~1.5MPa, vacuum degree is -85~-92kPa, and heat and pressure are maintained for 20~40min. This ensures that the resin is in the optimal rheological range, fully fills the pits on the surface of the aluminum plate, removes interfacial bubbles, and the thermally conductive filler is distributed synchronously and evenly.

[0048] (3) Gel-lock stage: temperature is 170-190℃, pressure is 1.5-2.5MPa, vacuum degree is -88--95kPa, and the temperature and pressure are maintained for 30-50min. In this stage, the resin begins to gel, locks the filler distribution, prevents excessive glue overflow, and avoids glue shortage.

[0049] (4) Curing stage: temperature is 190~210℃, pressure is 3.0~4.0MPa, vacuum degree is -88~-95kPa, heat and pressure are maintained for 60~90min; in this stage, the resin is completely cross-linked and cured to form a continuous and dense heat-conducting network.

[0050] (5) Gradient shaping stage: The temperature is gradually reduced to below 60℃ in sections, and the pressure is maintained for 20 to 30 minutes. This step eliminates the internal stress of the laminate, inhibits the warping of the board, and improves the dimensional stability.

[0051] This invention achieves a five-stage precision lamination process that perfectly matches the resin's rheological properties, resulting in uniform filler distribution, no bubbles, no missing resin, low internal stress, and extremely low warpage. The melting stage reduces resin viscosity by melting; the rheological filling stage ensures the resin fully fills interfacial grooves and removes air bubbles; the gel-locking stage locks in filler distribution and prevents excessive overflow; the curing stage allows complete cross-linking of the resin to form a stable structure; and the gradient setting stage slowly releases thermal stress and suppresses warpage. Overall, it achieves precise lamination in five stages, perfectly matching the resin's rheological properties, resulting in uniform filler distribution, no air bubbles, no missing resin, low internal stress, and extremely low warpage.

[0052] Furthermore, step S4 specifically includes:

[0053] After lamination, the pressure is maintained at 0.8-1.5 MPa and cooled to below 50°C by circulating water cooling. Then, the lamination assembly is removed from the high-temperature vacuum hot press, the supporting steel plate and steel cover are separated and recycled to the hot press station for reuse. The upper and lower buffer pads on the copper-clad laminate are then peeled off. Finally, the edge excess glue and burrs are removed using a cutting machine to obtain the finished product of high thermal conductivity aluminum-based copper-clad laminate.

[0054] In this invention, the resin is cooled to below 50°C to fully set, avoiding springback and warping caused by high-temperature decompression. This achieves stable dimensions, eliminates internal stress, ensures flatness, and results in finished products with high dimensional accuracy, no deformation, and no warping.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] (1) The present invention uses a three-gradient composite filler of large-particle-size and medium-particle-size spherical alumina and nano boron nitride. Through the synergistic filling of particle size distribution, a continuous, dense and void-free thermal conductivity path is formed. The resin viscosity is controlled by rheology modifier and the five-stage rheological lamination is used to achieve uniform dispersion of filler, avoid agglomeration and discontinuity, and greatly improve the overall thermal conductivity. This effectively solves the problem of low thermal conductivity and poor heat dissipation caused by single / two-stage filler in the prior art.

[0057] (2) The present invention employs a four-step composite treatment of aluminum plate, namely, alkaline washing and degreasing, micro-etching, low-temperature plasma activation and short-pulse laser directional roughening, to form a physical anchoring structure of micron-sized pits and directional grooves, and to achieve chemical bonding by generating active groups such as hydroxyl and carboxyl groups through plasma activation; at the same time, the copper foil is dusted and plasma activated, which greatly improves the bonding strength between the copper foil and the adhesive film, and improves the overall adhesion from the dual interface, solving the problems of single interface treatment, low peel strength and easy delamination due to thermal shock in the existing technology.

[0058] (3) The present invention adopts a five-stage rheological lamination process that matches the characteristics of the resin. Through melting, rheological filling, gel locking, curing, and gradient shaping, the temperature and pressure are controlled in stages to keep the resin in the best flow state at different stages. When stacking, a controllable overflow guide zone is set to realize orderly resin flow, uniform filling and timely venting, thereby reducing defects such as bubbles, white spots, missing glue and overflow from the source and significantly reducing the defect rate of finished products.

[0059] (4) After lamination and curing, the present invention adopts gradient cooling and step decompression process to slowly release the internal stress caused by the difference in thermal expansion coefficient between copper, aluminum and adhesive film, and avoid warping deformation caused by stress concentration; at the same time, the flatness is further improved by segmented drying of adhesive film and gel lock flow stabilization, so as to significantly reduce the warping of finished product and meet the requirements of high precision patching and processing.

[0060] (5) The present invention achieves uniform film formation, no impurities at the interface, no air bubbles or voids, and complete curing, so that the product can remain unbroken for more than 70 seconds under AC voltage above 4000V, and the insulation performance is more stable. Combined with strong interface bonding, low internal stress and low defect rate, the product does not crack, delaminate or fail under long-term high and low temperature impact, which can meet the high reliability requirements of high-end fields such as LED, new energy vehicle electronic control, 5G communication, etc.

[0061] In summary, this invention achieves comprehensive performance of high thermal conductivity, strong bonding, low defects, low warpage, and high reliability through the synergistic effect of core technical features such as three-gradient thermally conductive filler compounding, dual-interface reinforcement of aluminum plate and copper foil, segmented drying of adhesive film, five-stage rheological matching lamination, and controllable overflow of adhesive. It comprehensively solves common industry problems such as insufficient thermal conductivity, weak bonding, high defect rate, severe warpage, and poor reliability of existing aluminum-based copper clad laminates. The process is stable and can be mass-produced.

[0062] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0063] Figure 1 This is a process flow diagram of the present invention;

[0064] Figure 2 This is a bar chart showing the thermal conductivity of the embodiments and comparative examples of the present invention;

[0065] Figure 3 This is a bar chart showing the peel strength of the embodiments and comparative examples of the present invention;

[0066] Figure 4 This is a bar chart showing the warpage of the embodiments and comparative examples of the present invention;

[0067] Figure 5 This is a bar chart showing the defect rate of the embodiments and comparative examples of the present invention. Detailed Implementation

[0068] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0070] Example 1: A high thermal conductivity aluminum-based copper-clad laminate based on resin rheological properties, comprising an aluminum substrate, a high thermal conductivity rheological film, and a copper foil layer arranged sequentially. The raw materials for the high thermal conductivity rheological film include:

[0071] Resin matrix: 70g epoxy resin, 12g phenolic resin, 8g rubber toughening agent;

[0072] Thermally conductive fillers: 35g of large-particle-size spherical alumina (10-20μm), 18g of medium-particle-size spherical alumina (3-8μm), and 12g of nano-boron nitride (50-200nm);

[0073] Functional additives: 2g silane coupling agent, 4.5g composite curing agent, 1.2g rheology modifier.

[0074] The composite curing agent is a mixture of amine curing agent and acid anhydride curing agent in a mass ratio of 1:1.

[0075] Please refer to the attached document carefully. Figure 1 A method for laminating high thermal conductivity aluminum-based copper-clad laminates based on resin rheological properties includes the following steps:

[0076] Step 1: Raw material preparation

[0077] The aluminum plate undergoes interface treatment in the following four steps:

[0078] (1) Alkaline washing and degreasing: Immerse the aluminum plate in an alkaline degreasing solution of sodium hydroxide at a temperature of 55℃ and a mass concentration of 5% for 5 minutes to remove oil stains, fingerprints, dust and natural loose oxide layer from the surface of the aluminum plate; after taking it out, rinse it with running deionized water 2 to 3 times to wash away the residual alkali solution, and then dry it in a 90℃ oven for 7 minutes to ensure that the plate surface is dry, without watermarks and without residual alkali;

[0079] (2) Micro-etching treatment: The aluminum plate after alkaline washing and degreasing is immersed in the micro-etching solution for micro-etching. The micro-etching solution consists of: 12% sulfuric acid, 4% hydrogen peroxide and the remainder deionized water; the micro-etching temperature is 30℃ and the micro-etching time is 45s; through micro-etching, a uniform, continuous, micron-level pit structure with a depth of 0.5 to 1.5μm is formed on the surface of the aluminum plate, which improves the physical anchoring ability between the adhesive film and the aluminum plate; after micro-etching, it is immediately rinsed thoroughly with deionized water and dried with nitrogen gas.

[0080] (3) Low-temperature plasma activation: The micro-etched aluminum plate is sent into a low-temperature vacuum plasma treatment machine with a vacuum degree of -70 kPa; the working gas is a mixture of argon and oxygen with a volume ratio of 3:1 and a gas flow rate of 40 sccm; the treatment power is 300 W; and the treatment time is 90 s. Through plasma bombardment, micro-contaminants on the surface of the aluminum plate are removed, the surface energy is increased to more than 50 mN / m, and active groups such as hydroxyl and carboxyl groups are generated on the surface, which significantly enhances the chemical bonding ability between the resin and the aluminum plate.

[0081] (4) Short-pulse laser directional roughening: A short-pulse fiber laser was used to perform directional trench roughening on the aluminum plate after low-temperature plasma activation. The laser wavelength was 1064 nm, the pulse width was 20–100 ns, and the laser power was 20 W. The scanning speed was 2000 mm / s, the scanning line spacing was 80 μm, and the scanning path was a parallel unidirectional trench. Through laser directional etching, continuous trenches with uniform spacing were formed on the surface of the aluminum plate, and the surface roughness Ra of the aluminum plate was finally controlled at 2.0 μm, forming a three-dimensional interlocking interface of physical anchoring and chemical bonding.

[0082] Preparation of high thermal conductivity rheological adhesive films:

[0083] (1) Premixing and prepolymerizing resin matrix

[0084] Add solvent, such as acetone or ethyl acetate, to a constant-temperature high-speed dispersion reactor at a volume of 40 mL; start stirring at a speed of 400 r / min; then add epoxy resin, phenolic resin, and rubber toughening agent in sequence; heat to 60℃ and stir for 45 min to completely dissolve the resin and achieve uniform prepolymerization, resulting in a transparent and homogeneous matrix resin liquid.

[0085] (2) Surface modification and dispersion of thermally conductive fillers

[0086] Add silane coupling agent to the matrix resin solution and stir for 12 min; then add thermally conductive fillers in sequence: large-particle-size spherical alumina, medium-particle-size spherical alumina, and nano boron nitride; after each filler is added, stir and disperse for 10 min to prevent agglomeration; then add rheology modifier and disperse at a high speed of 1000 r / min for 25 min to ensure uniform dispersion of fillers and stable system viscosity within the optimal rheological range of 500–1500 Pa·s.

[0087] (3) Adding the curing system to the adhesive solution

[0088] Reduce the rotation speed to 350 r / min and add the composite curing agent; continue stirring for 18 min to mix thoroughly; then filter with a 200 mesh filter to remove agglomerated particles and impurities to obtain a high thermal conductivity rheological adhesive.

[0089] (4) Coating and segmented drying of adhesive film

[0090] A high thermal conductivity rheological adhesive liquid is applied to a PET release film using a precision coating machine at a speed of 5 m / min, resulting in an adhesive layer thickness of 120 μm. The film is then dried in stages in an oven. The first zone is controlled at 65℃ to dry the solvent; the second zone at 105℃ for initial de-adhesion; and the third zone at 145℃ for semi-curing and setting. After drying, the film is wound up to obtain a high thermal conductivity rheological adhesive film, which can be directly used for lamination.

[0091] Copper foil undergoes dust removal and oxidation surface activation treatment:

[0092] (1) Dust removal treatment on both sides of copper foil

[0093] Select 40μm thick rolled or electrolytic copper foil, load the copper foil into the unwinding station of the coating machine, and pass it through a three-stage dust removal unit: first, using 100g / m... 2 The adhesive paper roller is used to treat the upper and lower surfaces of the copper foil, removing dust, lint, and debris. Then, a high-pressure ion air gun (0.3 MPa, 15 mm from the copper foil surface) is used to blow away any remaining micro-dust. Finally, a clean, non-woven cloth is used to gently wipe the copper foil surface to ensure there are no visible contaminants, oil stains, or fingerprints. This ensures a clean copper foil surface and prevents bubbles, white spots, and interface defects from forming during lamination.

[0094] (2) Activation treatment of copper foil oxide surface

[0095] The dust-removed copper foil, with its oxide surface facing upwards, was fed into a low-temperature plasma activation machine for surface activation. The working gas was a mixture of argon and oxygen in a 4:1 volume ratio, with a gas flow rate of 45 sccm; the vacuum level was -60 kPa; the activation power was 200 W; the processing speed was 2.0 m / min; and the processing time was 60 s. After activation, the surface energy of the copper foil increased to over 55 mN / m; active groups such as hydroxyl and carbonyl groups were generated on the copper foil surface; and the micro-roughness of the oxide surface was slightly improved, forming strong chemical bonds with the high thermal conductivity rheological adhesive film.

[0096] (3) Temporary storage and protection of activated copper foil

[0097] Immediately place the activated copper foil into a dust-free, sealed channel and complete the lamination and bonding with the adhesive film within 10 minutes to avoid secondary surface contamination. Do not touch the activated surface of the copper foil with your hands to prevent oil stains and fingerprints from reducing the bonding strength.

[0098] Step 2: Stacking and arranging the pieces

[0099] Stack the supporting steel plate, lower buffer pad, copper foil (oxidized side down), high thermal conductivity rheological adhesive film, aluminum plate, upper buffer pad, and steel cover in sequence; leave a 0.5-1.0mm controllable overflow guide area at the edge of the stack to ensure uniform resin flow.

[0100] Step 3: Five-stage rheological matching lamination

[0101] The stacked carrier plate assembly is fed into a high-temperature vacuum multilayer hot press. The chamber door is closed and the vacuum system is activated. Following a preset five-stage rheological matching program, the entire process of heating, pressurizing, vacuuming, heat and pressure holding, gradient cooling, and step-by-step depressurization is automatically completed, achieving the lamination and molding of high thermal conductivity aluminum-based copper-clad laminates. The control parameters for each stage are as follows:

[0102] (1) Melting stage: The temperature is 100℃, the pressure is 0.35MPa, the vacuum degree is -70kPa, and the temperature and pressure are maintained for 15min. This allows the resin to melt completely, reduces the initial viscosity, and eliminates local agglomeration.

[0103] (2) Rheological filling stage: temperature is 150℃, pressure is 1.1MPa, vacuum degree is -88kPa, and heat and pressure are maintained for 30min. This ensures that the resin is in the optimal rheological range, fully fills the pits on the surface of the aluminum plate, removes interfacial bubbles, and ensures that the thermally conductive filler is distributed synchronously and evenly.

[0104] (3) Gel-lock stage: The temperature is 180℃, the pressure is 2.0MPa, the vacuum degree is -92kPa, and the temperature and pressure are maintained for 40min. In this stage, the resin begins to gel, locks the filler distribution, prevents excessive glue overflow, and avoids glue shortage.

[0105] (4) Curing stage: temperature is 200℃, pressure is 3.5MPa, vacuum degree is -92kPa, heat and pressure are maintained for 75min; in this stage, the resin is completely cross-linked and cured to form a continuous and dense heat-conducting network.

[0106] (5) Gradient shaping stage: The temperature is gradually reduced to 50°C in sections and held under pressure for 25 minutes. This step eliminates internal stress in the laminate, inhibits warping of the board, and improves dimensional stability.

[0107] Step 4: Post-processing

[0108] After lamination, the pressure is maintained at 1.2MPa and cooled to room temperature using circulating water cooling. The lamination assembly is then removed from the high-temperature vacuum hot press, and the supporting steel plate and steel cover are separated and recycled back to the hot press station for reuse. The upper and lower buffer pads on the copper-clad laminate are then peeled off. Finally, a cutting machine is used to remove excess adhesive and burrs from the edges, resulting in a high thermal conductivity aluminum-based copper-clad laminate.

[0109] Example 2: The difference between this example and Example 1 is that:

[0110] Step 1: Raw material preparation

[0111] Interface treatment of aluminum plates: During alkaline degreasing, the immersion temperature of sodium hydroxide alkaline degreasing solution is 50℃, the mass concentration is 3%, the immersion time is 3min, the drying temperature is 80℃, and the drying time is 10min; During micro-etching treatment, the micro-etching solution composition is: 10% sulfuric acid, 3% hydrogen peroxide, and the balance of deionized water; the micro-etching temperature is 25℃, and the micro-etching time is 60s; During low-temperature plasma activation, the vacuum degree is controlled at -60kPa, the gas flow rate is 20sccm, the processing power is 200W, and the processing time is 60s; During short-pulse laser directional roughening, the laser power is controlled at 10W, the scanning speed is 1500mm / s, and the scanning line spacing is 50μm, ultimately controlling the surface roughness Ra of the aluminum plate to 1.0μm.

[0112] Preparation of high thermal conductivity rheological adhesive film: During resin matrix premixing and prepolymerization, the solvent volume was 30 mL, and the stirring speed was controlled at 300 r / min; then, 60 g of epoxy resin, 10 g of phenolic resin, and 5 g of rubber toughening agent were added sequentially; the temperature was raised to 50℃ and stirred for 30 min. For surface modification and dispersion of thermally conductive fillers, 1 g of silane coupling agent was added to the matrix resin solution and stirred for 10 min; then, the following thermally conductive fillers were added sequentially: 30 g of large-particle-size spherical alumina, 15 g of medium-particle-size spherical alumina, and 8 g of nano-boron nitride; after each filler was added, the mixture was stirred and dispersed for 8 min; then, 0.5 g of rheology modifier was added and dispersed at a high speed of 800 r / min for 20 min. When adding the curing system to the adhesive solution, the stirring speed was reduced to 250 r / min, and 3 g of composite curing agent was added; stirring continued for 15 min; then the mixture was filtered through a 100-mesh filter. During the coating and segmented drying of the adhesive film, the coating speed is 3m / min and the adhesive layer thickness is 150μm; the temperature control in zone one is 50℃, the temperature control in zone two is 90℃, and the temperature control in zone three is 130℃.

[0113] Copper foil undergoes dust removal and oxidation surface activation treatment: For double-sided dust removal of copper foil, 18μm thick rolled or electrolytic copper foil is selected; 80g / m 2A dust-adhesive paper roller is used to adsorb dust onto the upper and lower surfaces of the copper foil. The high-pressure ion air gun has an air pressure of 0.2 MPa and is positioned 10 mm away from the copper foil surface. During the activation treatment of the copper foil oxide surface, the gas flow rate is 30 sccm, the vacuum degree is -50 kPa, the activation power is 100 W, the processing speed is 1.5 m / min, and the processing time is 90 s.

[0114] Step 3: Five-stage rheological matching lamination

[0115] The control parameters for each stage are as follows:

[0116] (1) Melting stage: temperature is 80℃, pressure is 0.2MPa, vacuum degree is -60kPa, heat and pressure are maintained for 10min;

[0117] (2) Rheological filling stage: temperature is 130℃, pressure is 0.8MPa, vacuum degree is -85kPa, heat and pressure are maintained for 20min;

[0118] (3) Gel lock stage: temperature is 170℃, pressure is 1.5MPa, vacuum degree is -88kPa, heat and pressure are maintained for 30min;

[0119] (4) Curing stage: temperature is 190℃, pressure is 3.0MPa, vacuum degree is -88kPa, heat and pressure are maintained for 60min;

[0120] (5) Gradient shaping stage: segmented gradient cooling to 60℃, pressure held for 20min.

[0121] Step 4: Post-processing

[0122] After lamination, the pressure is maintained at 0.8 MPa, and the material is cooled to room temperature using circulating water cooling.

[0123] Everything else is the same as in Example 1.

[0124] Example 3: The difference between this example and Example 1 is that:

[0125] Step 1: Raw material preparation

[0126] Interface treatment of aluminum plates: During alkaline degreasing, the immersion temperature of sodium hydroxide alkaline degreasing solution is 60℃, the mass concentration is 8%, the immersion time is 8min, the drying temperature is 100℃, and the drying time is 5min; During micro-etching treatment, the micro-etching solution composition is: sulfuric acid 15%, hydrogen peroxide 5%, and deionized water balance; the micro-etching temperature is 35℃, and the micro-etching time is 30s; During low-temperature plasma activation, the vacuum degree is controlled at -80kPa, the gas flow rate is 50sccm, the processing power is 400W, and the processing time is 120s; During short-pulse laser directional roughening, the laser power is controlled at 30W, the scanning speed is 2500mm / s, and the scanning line spacing is 100μm, ultimately controlling the surface roughness Ra of the aluminum plate to 3.0μm.

[0127] Preparation of high thermal conductivity rheological adhesive film: During resin matrix premixing and prepolymerization, the solvent volume was 50 mL, and the stirring speed was controlled at 500 r / min; then 80 g of epoxy resin, 15 g of phenolic resin, and 10 g of rubber toughening agent were added sequentially; the temperature was raised to 65℃ and stirred for 60 min. For surface modification and dispersion of thermally conductive fillers, 3 g of silane coupling agent was added to the matrix resin solution and stirred for 15 min; then, the following thermally conductive fillers were added sequentially: 40 g of large-particle-size spherical alumina, 20 g of medium-particle-size spherical alumina, and 15 g of nano-boron nitride; after each filler was added, the mixture was stirred and dispersed for 12 min; then 2 g of rheology modifier was added and dispersed at a high speed of 1200 r / min for 30 min. When adding the curing system to the adhesive solution, the stirring speed was reduced to 450 r / min, and 6 g of composite curing agent was added; stirring continued for 20 min; then the mixture was filtered through a 200-mesh filter. During the coating and segmented drying of the adhesive film, the coating speed is 8m / min and the adhesive layer thickness is 80μm; the temperature control in zone one is 80℃, the temperature control in zone two is 120℃, and the temperature control in zone three is 160℃.

[0128] Copper foil undergoes dust removal and oxidation surface activation treatment: For double-sided dust removal of copper foil, 70μm thick rolled or electrolytic copper foil is selected; 120g / m 2 A dust-adhesive paper roller is used to adsorb dust onto the upper and lower surfaces of the copper foil. The high-pressure ion air gun has an air pressure of 0.4 MPa and is positioned 20 mm away from the copper foil surface. During the activation treatment of the copper foil oxide surface, the gas flow rate is 60 sccm, the vacuum degree is -70 kPa, the activation power is 300 W, the processing speed is 3.0 m / min, and the processing time is 30 s.

[0129] Step 3: Five-stage rheological matching lamination

[0130] The control parameters for each stage are as follows:

[0131] (1) Melting stage: temperature is 120℃, pressure is 0.5MPa, vacuum degree is -80kPa, heat and pressure are maintained for 20min;

[0132] (2) Rheological filling stage: temperature is 170℃, pressure is 1.5MPa, vacuum degree is -92kPa, heat and pressure are maintained for 40min;

[0133] (3) Gel lock stage: temperature is 190℃, pressure is 2.5MPa, vacuum degree is -95kPa, heat and pressure are maintained for 50min;

[0134] (4) Curing stage: temperature is 210℃, pressure is 4.0MPa, vacuum degree is -95kPa, heat and pressure are maintained for 90min;

[0135] (5) Gradient shaping stage: segmented gradient cooling to 60℃, pressure holding for 30min.

[0136] Step 4: Post-processing

[0137] After lamination, the pressure is maintained at 1.5 MPa, and the temperature is cooled to 50°C using circulating water cooling.

[0138] Everything else is the same as in Example 1.

[0139] Comparative Example 1: The difference from Example 1 is that:

[0140] The aluminum plate interface treatment only involves alkaline washing and degreasing, micro-etching, and short-pulse laser directional roughening in sequence, without low-temperature plasma activation.

[0141] Everything else is the same as in Example 1.

[0142] Comparative Example 2: The difference from Example 1 is that:

[0143] The aluminum plate interface treatment only involves alkaline washing and degreasing, micro-etching, and low-temperature plasma activation in sequence, without short-pulse laser directional roughening.

[0144] Everything else is the same as in Example 1.

[0145] Comparative Example 3: The difference from Example 1 is that:

[0146] The thermally conductive filler in the raw material of the high thermal conductivity rheological film is 65g of medium-sized spherical alumina (3-8μm), and large-sized spherical alumina and nano boron nitride are not used.

[0147] Everything else is the same as in Example 1.

[0148] Comparative Example 4: The difference from Example 1 is that:

[0149] The copper foil is only dusted, not subjected to oxidation surface activation treatment.

[0150] Everything else is the same as in Example 1.

[0151] Comparative Example 5: The difference from Example 1 is that:

[0152] The lamination process is undivided, with a constant temperature of 200℃ and a constant pressure of 3.5MPa throughout, without gradient heating or pressurization.

[0153] Everything else is the same as in Example 1.

[0154] Comparative Example 6: The difference from Example 1 is that:

[0155] The lamination process skips the gel lock stage and proceeds directly from the rheological filling stage to the curing stage.

[0156] Everything else is the same as in Example 1.

[0157] Comparative Example 7: The difference from Example 1 is that:

[0158] In the lamination process, rapid cooling occurs immediately after the curing stage, without segmented gradient cooling, and the pressure is not released in a stepwise manner.

[0159] Everything else is the same as in Example 1.

[0160] Comparative Example 8: The difference from Example 1 is that:

[0161] No overflow adhesive drainage area is reserved during stacking.

[0162] Everything else is the same as in Example 1.

[0163] Comparative Example 9: The difference from Example 1 is that:

[0164] The film drying process does not involve three zones; it is uniformly dried at 145℃ in one pass.

[0165] Everything else is the same as in Example 1.

[0166] Comparative Example 10: The difference from Example 1 is that:

[0167] No rheology modifiers are added during the preparation of the film, and the viscosity of the system is not controlled.

[0168] Everything else is the same as in Example 1.

[0169] To verify the advantages of the present invention, comparative tests were conducted on the above embodiments and comparative examples:

[0170] 1. Thermal conductivity

[0171] The test method followed GB / T22588-2008 "Test of Thermal Conductivity of Materials - Hot Wire Method". A hot wire thermal conductivity meter was used, and the test temperature was 25℃. The thermal conductivity was measured, and the unit is W / (m·K). The higher the value, the better the heat dissipation performance. The test results are shown in Table 1 and... Figure 2 As shown.

[0172] Table 1. Thermal conductivity test data for the examples and comparative examples.

[0173] sample Thermal conductivity (W / (m・K)) sample Thermal conductivity (W / (m・K)) Example 1 3.8 Comparative Example 5 3.2 Example 2 3.1 Comparative Example 6 3.3 Example 3 4.3 Comparative Example 7 3.8 Comparative Example 1 3.7 Comparative Example 8 3.6 Comparative Example 2 3.6 Comparative Example 9 3.5 Comparative Example 3 2.5 Comparative Example 10 3.0 Comparative Example 4 3.7 / /

[0174] 2. Peel Strength

[0175] The test method refers to IPC-TM-650 2.4.9 "Test for Peel Strength of Copper Foil and Substrate". An electronic universal testing machine is used with a peel speed of 50 mm / min to test the peel strength of 180° peel. The unit is N / cm. The higher the value, the stronger the interfacial bonding force. The test results are shown in Table 2 and Figure 3 as follows.

[0176] Table 2 Data Sheet of Peel Strength Test for Examples and Comparative Examples

[0177] sample Peel strength (N / cm) sample Peel strength (N / cm) Example 1 1.6 Comparative Example 5 1.3 Example 2 1.3 Comparative Example 6 1.4 Example 3 1.8 Comparative Example 7 1.5 Comparative Example 1 1.1 Comparative Example 8 1.4 Comparative Example 2 1.0 Comparative Example 9 1.3 Comparative Example 3 1.5 Comparative Example 10 1.2 Comparative Example 4 1.2 / /

[0178] 3. Warpage

[0179] The test method refers to IPC-TM-650 2.4.22 "Test for Warpage and Twist of Printed Circuit Boards". A laser warpage measuring instrument is used. The test temperature is 25°C and the board size is 300 mm × 300 mm. The warpage of the board is tested. The unit is %, and the lower the value, the better the dimensional stability. The test results are shown in Table 3 and Figure 4 as follows.

[0180] Table 3 Data Sheet of Warpage Test for Examples and Comparative Examples

[0181] sample Warpage (%) sample Warpage (%) Example 1 0.20 Comparative Example 5 0.65 Example 2 0.30 Comparative Example 6 0.50 Example 3 0.15 Comparative Example 7 0.70 Comparative Example 1 0.22 Comparative Example 8 0.35 Comparative Example 2 0.25 Comparative Example 9 0.28 Comparative Example 3 0.21 Comparative Example 10 0.42 Comparative Example 4 0.23 / /

[0182] 4. AC Withstand Voltage

[0183] Test method: Use an AC withstand voltage tester. Apply an AC voltage of more than 4000V to the sample in an environment of 25°C and maintain the voltage for 70 seconds. Observe whether the sample is broken down. If it can maintain without breakdown for more than 70 seconds under an AC voltage of more than 4000V, it is qualified. The voltage rise rate is 500V / s. The qualified judgment basis is no breakdown, no flashover, and no carbonization. The test results are shown in Table 4.

[0184] Table 4 Data Sheet of AC Withstand Voltage Test for Examples and Comparative Examples

[0185] sample 4000V AC, withstand voltage for 70 seconds sample 4000V AC, withstand voltage for 70 seconds Example 1 qualified Comparative Example 5 Unqualified Example 2 qualified Comparative Example 6 Unqualified Example 3 qualified Comparative Example 7 qualified Comparative Example 1 qualified Comparative Example 8 Unqualified Comparative Example 2 qualified Comparative Example 9 Unqualified Comparative Example 3 qualified Comparative Example 10 Unqualified Comparative Example 4 qualified / /

[0186] 5. Defect Rate

[0187] Use visual and microscopic observation (magnification 20 times) as the test method. An optical microscope is used as the instrument. Randomly select 100 finished products and count the proportion of defects such as bubbles, lack of glue, overflow of glue, delamination, etc. The unit is %. The lower the data, the better. The test results are shown in Table 5 and Figure 5 as follows.

[0188] Table 5 Defect Rate Test Data Table of Examples and Comparative Examples

[0189] sample Defect rate (%) sample Defect rate (%) Example 1 0.8 Comparative Example 5 8.5 Example 2 1.5 Comparative Example 6 6.2 Example 3 0.5 Comparative Example 7 2.1 Comparative Example 1 2.3 Comparative Example 8 7.8 Comparative Example 2 3.1 Comparative Example 9 5.3 Comparative Example 3 1.2 Comparative Example 10 9.1 Comparative Example 4 2.8 / /

[0190] 6. Thermal Shock Stability

[0191] The test method refers to IEC60068-2-14 "Environmental Testing - Part 2-14: Test Methods - Test N: Change of Temperature". Using a high and low temperature shock test chamber, cycle 500 times between the two conditions of placing for 30 minutes at -40°C and placing for 30 minutes at 125°C. Then check whether the board is delaminated or cracked. If there is no delamination or cracking, it is qualified, and record whether it fails. The test results are shown in Table 6.

[0192] Table 6 Thermal Shock Stability Test Data Table of Examples and Comparative Examples

[0193] sample 500 cycles of thermal shock (whether it fails) sample 500 cycles of thermal shock (whether it fails) Example 1 Not expired Comparative Example 5 Localized bubble cracking Example 2 Not expired Comparative Example 6 Edge glue overflow caused delamination Example 3 Not expired Comparative Example 7 Overall warping failure Comparative Example 1 Not expired Comparative Example 8 Both glue shortage and glue overflow exist. Comparative Example 2 Slight layering at the edges Comparative Example 9 Residual solvent in the adhesive film causes bubbles Comparative Example 3 Not expired Comparative Example 10 Packing agglomeration leads to localized thermal conductivity failure Comparative Example 4 Not expired / /

[0194] From Table 1 - Table 6 and Figures 2-5 it can be seen that

[0195] (1) The comprehensive performance of Examples 1 to 3 is the best, with the highest thermal conductivity of 4.3 W / (m·K), the highest peel strength of 1.8 N / cm, the lowest warp of 0.15%, all passing the 4000V AC withstand voltage test for 70 seconds, the defect rate ≤ 1.5%, and no failure after 500 thermal shocks, significantly superior to all comparative examples.

[0196] (2) Comparative Example 3 uses single-sized alumina, with a thermal conductivity of only 2.5 W / (m·K) and a discontinuous thermal conduction network.

[0197] (3) The peel strength of Comparative Example 1 (lacking plasma activation), Comparative Example 2 (without laser roughening), and Comparative Example 4 (copper foil not activated) decreased significantly, with easy delamination and increased defects.

[0198] (4) For Comparative Example 5 (constant temperature and pressure), Comparative Example 6 (without gel locking flow), and Comparative Example 8 (without overflow glue diversion area), the warp increased significantly, the defect rate soared, and the AC withstand voltage was unqualified.

[0199] (5) For Comparative Example 9 (one-step drying) and Comparative Example 10 (without additives), it is easy to form bubbles and the filler agglomerates, resulting in withstand voltage failure; for Comparative Example 7 (without gradient cooling), it is easy to warp and seriously fail.

[0200] In summary, through the synergistic effect of three-gradient fillers, double-interface strengthening, five-stage lamination, controllable overflow glue, segmented drying, and gradient shaping, the present invention realizes stable performance of high thermal conductivity, strong bonding, low warp, low defects, and high AC withstand voltage, which can meet the high reliability requirements of high-end heat dissipation scenarios.

[0201] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A method for laminating high thermal conductivity aluminum-based copper-clad laminates based on resin rheological properties, characterized in that: Includes the following steps: S1. Raw material preparation: Prepare aluminum plates, high thermal conductivity rheological adhesive films and copper foils respectively. The aluminum plates are subjected to four interface treatments in sequence: alkaline washing and degreasing, micro-etching treatment, low temperature plasma activation and short pulse laser directional roughening. The copper foils are subjected to dust removal and oxidation surface activation treatment. S2. Stacking arrangement: Stack the supporting steel plate, lower buffer pad, copper foil, high thermal conductivity rheological adhesive film, aluminum plate, upper buffer pad, and steel cover in sequence, and reserve a controllable overflow guide area at the edge; S3, Five-stage rheological matching lamination: Vacuum hot pressing is performed on the carrier plate assembly after the stacked arrangement is completed. The control is divided into five stages, namely the melting stage, rheological filling stage, gel lock stage, curing stage and gradient shaping stage. S4. Post-processing: After lamination, the laminated components are cooled, separated by a tooling, the buffer pad is peeled off, and cut to obtain a high thermal conductivity aluminum-based copper-clad laminate.

2. The method for laminating high thermal conductivity aluminum-based copper-clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S1, the four-step interface processing of the aluminum plate specifically includes: (1) Alkaline washing and degreasing: Immerse the aluminum plate in an alkaline degreasing solution of sodium hydroxide at a temperature of 50-60℃ and a mass concentration of 3%-8% for 3-8 minutes; after taking it out, wash off the residual alkali solution with flowing deionized water, and then dry it in an oven at 80-100℃ for 5-10 minutes. (2) Micro-etching treatment: The aluminum plate after alkaline washing and degreasing is immersed in micro-etching solution for micro-etching. The composition of micro-etching solution is: sulfuric acid 10% to 15%, hydrogen peroxide 3% to 5% and deionized water balance; the micro-etching temperature is 25 to 35℃ and the micro-etching time is 30 to 60s; after micro-etching, rinse thoroughly with deionized water and dry with nitrogen gas. (3) Low-temperature plasma activation: The aluminum plate after micro-etching is sent into a low-temperature vacuum plasma treatment machine with a vacuum degree of -60 to -80 kPa, a treatment power of 200 to 400 W, and a treatment time of 60 to 120 s; (4) Short-pulse laser directional roughening: A short-pulse fiber laser is used to perform directional groove roughening on the aluminum plate after low-temperature plasma activation. The laser wavelength is 1064nm, the pulse width is 20-100ns, the laser power is 10-30W, the scanning speed is 1500-2500mm / s, the scanning line spacing is 50-100μm, and the scanning path is parallel unidirectional groove. Finally, the surface roughness Ra of the aluminum plate is controlled at 1.0-3.0μm.

3. The method for laminating high thermal conductivity aluminum-based copper-clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S1, the raw materials for the high thermal conductivity rheological adhesive film include, by weight: Resin matrix: 60-80 parts epoxy resin, 10-15 parts phenolic resin, 5-10 parts rubber toughening agent; Thermally conductive filler: 30-40 parts of large-particle-size spherical alumina, 15-20 parts of medium-particle-size spherical alumina, and 8-15 parts of nano-boron nitride; wherein the particle size of the large-particle-size spherical alumina is 10-20 μm, the particle size of the medium-particle-size spherical alumina is 3-8 μm, and the particle size of the nano-boron nitride is 50-200 nm; Functional additives: 1-3 parts silane coupling agent, 3-6 parts composite curing agent, and 0.5-2 parts rheology modifier.

4. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 3, characterized in that: In step S1, the preparation method of the high thermal conductivity rheological adhesive film is as follows: (1) Premixing and prepolymerizing the resin matrix: Acetone or ethyl acetate is used as solvent, with a dosage of 30 to 50 parts; under stirring conditions, epoxy resin, phenolic resin and rubber toughening agent are added in sequence, and the temperature is raised to 50 to 65°C, and stirred for 30 to 60 minutes to obtain a transparent and uniform matrix resin liquid. (2) Surface modification and dispersion of thermally conductive filler: Add silane coupling agent to the matrix resin liquid and stir for 10-15 min; then add large-diameter spherical alumina, medium-diameter spherical alumina, and nano boron nitride in sequence and stir to disperse; then add rheology modifier and disperse at high speed at 800-1200 r / min for 20-30 min, and control the viscosity of the system to be stable in the optimal rheological range of 500-1500 Pa·s; (3) Addition of curing system and preparation of adhesive: Add composite curing agent and stir to mix evenly. The composite curing agent is a mixture of amine curing agent and acid anhydride curing agent in a mass ratio of 1:

1. Then filter with a filter screen to remove agglomerated particles and impurities to obtain high thermal conductivity rheological adhesive. (4) Coating and segmented drying of adhesive film: The high thermal conductivity rheological adhesive liquid is coated on the PET release film with an adhesive layer thickness of 80-150μm. Then, it is dried in segments. The temperature of the first zone is controlled at 50-80℃, the temperature of the second zone is controlled at 90-120℃, and the temperature of the third zone is controlled at 130-160℃. After drying, it is rolled up to obtain the high thermal conductivity rheological adhesive film.

5. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S1, rolled copper foil or electrolytic copper foil with a thickness of 18-70 μm is used. The oxidation surface activation treatment is specifically as follows: the copper foil with the oxide surface facing upward is sent into a low-temperature plasma activation machine for surface activation. The working gas is a mixture of argon and oxygen in a volume ratio of 4:1, the gas flow rate is 30-60 sccm, the vacuum degree is -50 to -70 kPa, the activation power is 100-300 W, the processing speed is 1.5-3.0 m / min, and the processing time is 30-90 s.

6. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S1, the copper foil oxide surface is activated and immediately placed into a dust-free sealed channel, and the lamination with the adhesive film is completed within 10 minutes.

7. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S2, the oxidized side of the copper foil faces down.

8. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S2, the width of the controllable overflow guide zone is 0.5 to 1.0 mm.

9. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S3, the control parameters for the five stages are as follows: (1) Melting stage: temperature is 80~120℃, pressure is 0.2~0.5MPa, vacuum degree is -60~-80kPa, heat and pressure are maintained for 10~20min; (2) Rheological filling stage: temperature is 130~170℃, pressure is 0.8~1.5MPa, vacuum degree is -85~-92kPa, heat and pressure are maintained for 20~40min; (3) Gel lock stage: temperature is 170~190℃, pressure is 1.5~2.5MPa, vacuum degree is -88~-95kPa, heat and pressure are maintained for 30~50min; (4) Curing stage: temperature is 190~210℃, pressure is 3.0~4.0MPa, vacuum degree is -88~-95kPa, heat and pressure are maintained for 60~90min; (5) Gradient shaping stage: The temperature is reduced in segments to below 60℃ and held at pressure for 20-30 minutes.

10. The method for laminating high thermal conductivity aluminum-based copper clad laminates based on resin rheological properties according to claim 1, characterized in that: In step S4, the cooling process involves maintaining the pressure at 0.8–1.5 MPa and cooling the temperature to below 50°C.

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