Low-CTE self-repairing precise high-frequency anti-interference copper clad laminate

Abstract

The invention relates to the technical field of copper-clad substrates, in particular to a low-CTE self-repairing precise high-frequency anti-interference copper-clad substrate which comprises a shielding layer, a dielectric layer and a conducting layer which are sequentially arranged from bottom to top. The dielectric layer comprises a high-thermal-conductivity low-expansion layer, a temperature compensation layer and a self-repairing layer, the high-thermal-conductivity low-expansion layer is connected with the shielding layer and located on one side of the shielding layer, the temperature compensation layer is connected with the high-thermal-conductivity low-expansion layer, and the self-repairing layer is located between the temperature compensation layer and the conductive layer; through the dielectric layer structure of functional gradient design and special interface treatment, the substrate has the characteristics of low thermal expansion, dielectric constant temperature stability, crack self-repairing capability and electromagnetic anti-interference capability at the same time, and is suitable for the fields of high-frequency communication, aerospace and the like with high requirements on the performance of the substrate.

Description

Technical Field

[0001] This invention relates to the field of copper clad laminate technology, and in particular to a low-CTE self-healing precision high-frequency anti-interference copper clad laminate. Background Technology

[0002] In the field of high-frequency copper-clad laminate technology, improving the long-term reliability of circuits under harsh environments remains a serious and ongoing challenge. In particular, in composite materials filled with a large amount of inorganic ceramics in pursuit of properties such as low coefficient of thermal expansion and high thermal conductivity, the sacrifice of material toughness makes them more prone to microcracks under thermal cycling or mechanical stress.

[0003] Existing technologies mainly delay crack initiation by optimizing material formulations and processes, or by enhancing initial strength to resist crack germination. However, once microcracks form inside the substrate or at critical interfaces (such as the copper foil-dielectric layer interface), there is a lack of effective means of suppression. Their irreversible propagation will lead to the gradual deterioration of the mechanical and electrical properties of the circuit, eventually causing fatal failures such as open circuits and signal distortion. Summary of the Invention

[0004] The purpose of this invention is to provide a low-CTE self-healing precision high-frequency anti-interference copper-clad foil substrate, which solves the technical problem of decreased circuit reliability caused by irreversible propagation of microcracks in existing high-frequency copper-clad foil substrates.

[0005] To achieve the above objectives, the present invention provides a low CTE self-healing precision high-frequency anti-interference copper clad laminate, comprising a shielding layer, a dielectric layer and a conductive layer, wherein the shielding layer, the dielectric layer and the conductive layer are arranged sequentially from bottom to top; The dielectric layer includes a high thermal conductivity and low expansion layer, a temperature compensation layer, and a self-healing layer. The high thermal conductivity and low expansion layer is connected to the shielding layer and is located on one side of the shielding layer. The temperature compensation layer is connected to the high thermal conductivity and low expansion layer. The self-healing layer is located between the temperature compensation layer and the conductive layer.

[0006] The shielding layer has a porous ceramic absorbing layer formed by plasma electrolytic oxidation on its surface facing the dielectric layer.

[0007] The conductive layer is a low-roughness copper foil, and the interface between the conductive layer and the dielectric layer is provided with a micro-nano trench structure, and the trench is pre-filled with a self-healing material.

[0008] The temperature compensation layer is based on polytetrafluoroethylene and filled with a composite filler consisting of positive temperature coefficient ceramic and negative temperature coefficient ferrite. The positive temperature coefficient ceramic is semiconductor barium titanate, and the negative temperature coefficient ferrite is manganese zinc ferrite, with a mass ratio of 1:0.5 to 1:2.

[0009] The self-healing material is a polymer resin doped with micron or nano-conductive fillers.

[0010] The self-healing layer comprises a polymer matrix and micron-sized repair capsules and nano-sized fibrous repair carriers dispersed therein; the micron-sized repair capsules encapsulate a liquid repair agent, and the nano-sized fibrous repair carriers encapsulate a polymerization catalyst.

[0011] The high thermal conductivity and low expansion layer, the temperature compensation layer and the self-healing layer are integrated on the same reinforcing fiber skeleton through sequential impregnation and co-curing processes; the reinforcing fiber skeleton is open-fiber glass fiber cloth or quartz fiber cloth.

[0012] The present invention discloses a low CTE self-healing precision high-frequency anti-interference copper-clad laminate substrate. The high thermal conductivity and low expansion layer effectively controls thermal deformation and improves heat dissipation efficiency; the temperature compensation layer ensures the extreme stability of the dielectric constant in a wide temperature range; and the self-healing layer achieves self-healing capability through a multi-scale repair network composed of micron-scale capsules and nano-scale fiber carriers, thereby improving the service life of the substrate. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0014] Figure 1 This invention relates to a low-CTE self-healing precision high-frequency anti-interference copper-clad substrate.

[0015] Figure 2 This is the invention Figure 1 Enlarged view of point A.

[0016] In the diagram: 101-Shielding layer, 102-Dielectric layer, 103-Conductive layer, 104-High thermal conductivity and low expansion layer, 105-Temperature compensation layer, 106-Self-healing layer. Detailed Implementation

[0017] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0018] First embodiment: Please see Figure 1 and Figure 2 ,in Figure 1 It is a low-CTE self-healing precision high-frequency anti-interference copper-clad substrate. Figure 2 yes Figure 1 Enlarged view of point A.

[0019] This invention provides a low-CTE self-healing precision high-frequency anti-interference copper-clad laminate, comprising a shielding layer 101, a dielectric layer 102, and a conductive layer 103. The dielectric layer 102 includes a high thermal conductivity and low expansion layer 104, a temperature compensation layer 105, and a self-healing layer 106. Through the multi-layer structure of the dielectric layer 102, the technical problems of reliability degradation caused by irreversible propagation of microcracks in existing high-frequency substrates, as well as the difficulty in synergistically improving low CTE, dielectric stability, and anti-interference performance, are solved.

[0020] In this specific embodiment, the shielding layer 101, the dielectric layer 102, and the conductive layer 103 are arranged sequentially from bottom to top. The dielectric layer 102 includes a high thermal conductivity and low expansion layer 104, a temperature compensation layer 105, and a self-healing layer 106. The high thermal conductivity and low expansion layer 104 is connected to the shielding layer 101 and is located on one side of the shielding layer 101. The temperature compensation layer 105 is connected to the high thermal conductivity and low expansion layer 104. The self-healing layer 106 is located between the temperature compensation layer 105 and the conductive layer 103.

[0021] Furthermore, the temperature compensation layer 105 uses polytetrafluoroethylene as a matrix and is filled with a composite filler composed of positive temperature coefficient ceramic and negative temperature coefficient ferrite; the positive temperature coefficient ceramic is semiconductor barium titanate, and the negative temperature coefficient ferrite is manganese zinc ferrite, with a mass ratio of 1:0.5 to 1:2.

[0022] The self-healing layer 106 includes a polymer matrix and micron-sized repair capsules and nano-sized fibrous repair carriers dispersed therein; the micron-sized repair capsules encapsulate a liquid repair agent, and the nano-sized fibrous repair carriers encapsulate a polymerization catalyst.

[0023] In this embodiment, the high thermal conductivity and low expansion layer 104 uses polytetrafluoroethylene (PTFE) as the resin matrix and is filled with 60-70% by mass of sheet-like boron nitride filler. The filler sheet diameter is 5-15 μm and the thickness is 0.5-2 μm. By controlling the flow field parameters during the impregnation process, the sheet-like filler is oriented in-plane within the layer, forming an effective thermal conductivity path and improving the in-plane thermal conductivity of the substrate. This reduces the coefficient of thermal expansion of the high thermal conductivity and low expansion layer 104 and improves its thermal conductivity. The temperature compensation layer 105 uses PTFE as the matrix and uniformly disperses a composite filler composed of barium titanate semiconductor and manganese zinc ferrite. The preferred mass ratio of barium titanate semiconductor to manganese zinc ferrite is 1:1, and the total filler fraction is controlled at 40-50%. Ball milling ensures uniform mixing and full dispersion of the two fillers. When the temperature rises, the barium titanate semiconductor... The dielectric constant of barium increases accordingly, while the dielectric constant of manganese-zinc ferrite decreases accordingly. The two produce opposite dielectric temperature effects, causing their temperature coefficients to compensate and cancel each other out. This controls the rate of change of dielectric constant to a very small range within a wide temperature range of -55℃ to 150℃, effectively suppressing circuit resonant frequency shift and phase distortion caused by temperature fluctuations, and improving the performance consistency and reliability of phase-sensitive circuits at different operating temperatures. The self-healing layer 106 uses polytetrafluoroethylene as a matrix, with micron-sized repair capsules encapsulating dicyclopentadiene liquid repair agent, and nano-sized fibrous repair carriers encapsulating Grubbs catalyst. When microcracks occur in the material, crack propagation simultaneously destroys the microcapsules, releasing the repair agent and severing the nanofibers, releasing the catalyst. After contact at the crack fracture surface, the two undergo ring-opening metathesis polymerization to form a strong cross-linked polymer, thus repairing the crack.

[0024] The shielding layer 101 has a porous ceramic absorbing layer formed by plasma electrolytic oxidation on its surface facing the dielectric layer 102.

[0025] In this embodiment, the shielding layer 101 is made of an aluminum alloy substrate with a thickness of 1.5 mm. A porous ceramic absorbing layer with a thickness of 15-25 μm is formed on its surface by plasma electrolytic oxidation treatment. The porosity of the porous layer is 30-50%, and the pore size distribution is 1-5 μm, which can effectively absorb electromagnetic interference.

[0026] Secondly, the conductive layer 103 is a low-roughness copper foil, and the interface between it and the dielectric layer 102 is provided with a micro-nano trench structure, and the trench is pre-filled with a self-healing material.

[0027] Furthermore, the self-healing material is a polymer resin doped with micron or nano-conductive fillers.

[0028] In this embodiment, the conductive layer 103 is a low-roughness copper foil with a surface roughness Rz≤2μm. A micro-nano trench structure with a depth of 3-8μm and a width of 5-15μm is formed at the interface between the conductive layer 103 and the dielectric layer 102 using laser etching. The trench spacing is 20-50μm. The self-healing material pre-filled in the trenches is epoxy resin doped with silver nanoparticles, wherein the mass fraction of the silver nanoparticles is 10-20% and the particle size is 50-100nm. The trench structure increases the interface contact area, strengthening the mechanical anchoring effect between the conductive layer 103 and the dielectric layer 102. When microcracks occur at the interface due to thermal stress or other factors, the self-healing material pre-filled in the trenches can be released in time. The silver nanoparticles, while repairing the mechanical bond, also rebuild the electrical connection, ensuring the stability of high-frequency signal transmission.

[0029] Second embodiment: Based on the first embodiment, the high thermal conductivity and low expansion layer 104, temperature compensation layer 105 and self-healing layer 106 of this embodiment are integrated on the same reinforcing fiber skeleton through sequential impregnation and co-curing process; the reinforcing fiber skeleton is open fiberglass cloth or quartz fiber cloth.

[0030] In this embodiment, the sequential impregnation process specifically includes the following steps: First, the reinforcing fibers are impregnated in a high thermal conductivity, low expansion layer slurry with a viscosity of 2000-3000 cP and an impregnation speed controlled at 2-5 m / min; then, a temperature compensation layer slurry is introduced, with its viscosity adjusted to 1500-2500 cP; finally, a self-healing layer slurry is used, with a viscosity controlled at 1000-2000 cP. After each impregnation step, a gradient drying process is performed at 120-150℃ to finally form the dielectric layer 102 with a thickness of 0.1-0.5 mm; the reinforcing fiber skeleton is selected from open-fiber glass fibers with a thickness of 0.03-0.05 mm. The fabric has a fiber opening rate of ≥95%, ensuring the full penetration and uniform distribution of various functional fillers between fibers. The co-curing process adopts a programmed temperature rise vacuum hot pressing process, which specifically includes three stages: the first stage is held at 100℃ and 1MPa for 30 minutes to allow the layers to initially fuse; the second stage is heated to 200℃ and held at 2MPa for 60 minutes to complete the initial curing of the resin; the third stage is held at 360℃ and 3MPa for 90 minutes to achieve complete curing and interface fusion. The integrated molding process of this invention effectively avoids the interface delamination problem that is prone to occur in traditional lamination processes, ensuring the long-term reliability of the substrate under high temperature and high frequency working environment.

[0031] The low CTE self-healing precision high-frequency anti-interference copper-clad laminate of the present invention firstly forms a porous ceramic absorbing layer by plasma electrolytic oxidation of the shielding layer 101, and forms a micro-nano trench structure by laser etching of the conductive layer 103 and pre-filling it with self-healing material; then, the high thermal conductivity and low expansion layer 104, the temperature compensation layer 105 and the self-healing layer 106 are sequentially constructed on the reinforcing fiber skeleton by a sequential impregnation process to form the dielectric layer 102; finally, the shielding layer 101, the dielectric layer 102 and the conductive layer 103 are sequentially stacked and integrally formed by a programmed temperature and pressure vacuum hot pressing process.

[0032] The present invention has the following beneficial effects: The constructed multi-scale self-healing system achieves all-round damage repair from in-plane to Z-axis, significantly improving the service life of the substrate under thermal stress cycling; the micro-nano trench structure and pre-filled self-healing material at the interface effectively prevent interface delamination and ensure connection reliability during long-term use.

[0033] The temperature compensation layer maintains a stable dielectric constant over a wide temperature range through the synergistic effect of PTC / NTC fillers, providing a reliable signal transmission environment for high-frequency circuits; the shielding layer's wave-absorbing design effectively suppresses electromagnetic interference and ensures signal integrity.

[0034] The integrated molding process avoids the interface problems of traditional lamination processes, ensuring the strong bonding between layers; the sequential impregnation and programmed curing processes enable precise control of the gradient structure, ensuring the consistency and stability of product performance.

[0035] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A low-CTE self-healing precision high-frequency anti-interference copper-clad laminate, characterized in that, It includes a shielding layer, a dielectric layer, and a conductive layer, which are arranged sequentially from bottom to top; The dielectric layer includes a high thermal conductivity and low expansion layer, a temperature compensation layer, and a self-healing layer. The high thermal conductivity and low expansion layer is connected to the shielding layer and is located on one side of the shielding layer. The temperature compensation layer is connected to the high thermal conductivity and low expansion layer. The self-healing layer is located between the temperature compensation layer and the conductive layer.

2. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 1, characterized in that, The shielding layer has a porous ceramic absorbing layer formed by plasma electrolytic oxidation on its surface facing the dielectric layer.

3. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 1, characterized in that, The conductive layer is a low-roughness copper foil, and the interface between it and the dielectric layer has a micro-nano trench structure, with self-healing material pre-filled in the trench.

4. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 1, characterized in that, The temperature compensation layer uses polytetrafluoroethylene as a matrix and is filled with a composite filler consisting of positive temperature coefficient ceramic and negative temperature coefficient ferrite; the positive temperature coefficient ceramic is semiconductor barium titanate and the negative temperature coefficient ferrite is manganese zinc ferrite, with a mass ratio of 1:0.5 to 1:

2.

5. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 3, characterized in that, The self-healing material is a polymer resin doped with micron or nano-conductive fillers.

6. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 1, characterized in that, The self-healing layer comprises a polymer matrix and micron-sized repair capsules and nano-sized fibrous repair carriers dispersed therein; the micron-sized repair capsules encapsulate a liquid repair agent, and the nano-sized fibrous repair carriers encapsulate a polymerization catalyst.

7. The low CTE self-healing precision high-frequency anti-interference copper-clad laminate as described in claim 1, characterized in that, The high thermal conductivity and low expansion layer, temperature compensation layer and self-healing layer are integrated on the same reinforcing fiber skeleton through sequential impregnation and co-curing processes; the reinforcing fiber skeleton is open fiberglass cloth or quartz fiber cloth.

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