Preparation method of high-orientation graphene-copper composite structure
By pretreating the copper matrix and preparing the interface confinement structure, the problems of random orientation and weak interfacial bonding in graphene-copper composite materials were solved, and the preparation of highly oriented and highly intact graphene-copper composite structures was achieved, improving the conductivity and process controllability.
Patent Information
- Application Number
- CN202511776700.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-02-10
AI Technical Summary
In existing graphene-copper composite materials, the graphene orientation is random, the interfacial bonding is weak, and it is difficult to achieve large-area uniform growth. Traditional CVD processes are difficult to achieve the preparation of highly oriented and highly intact composite structures.
By pretreating the copper substrate to form a preferred crystal plane, an interface confinement structure is constructed, graphene is grown in the confinement space, and the confinement layer is removed by wet etching or mechanical peeling. Combined with low-temperature annealing or hot pressing, the interface bonding force is enhanced.
It achieves highly oriented growth of graphene, significantly improving grain orientation consistency and interfacial bonding, reducing defect density, and enhancing conductivity and sheet resistance. The process is highly controllable and suitable for large-scale production.
Smart Images
Figure CN121496352A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of graphene composite materials technology, and in particular to a method for preparing a highly oriented graphene-copper composite structure. Background Technology
[0002] Graphene is widely used in electronic packaging, heat dissipation materials and high-end electrical materials due to its excellent electrical conductivity, thermal conductivity and mechanical properties. Copper substrate has good electrical conductivity and metal catalytic properties, and is a commonly used substrate for preparing graphene / copper composite materials. At present, the main method for growing graphene on copper is chemical vapor deposition (CVD), but the traditional open growth process still has the following problems: (1) Random nucleation and poor orientation consistency. Active carbon atoms diffuse freely in the open system, resulting in random nucleation of graphene on the copper surface, dispersed grain orientation and poor overall texture. (2) Insufficient crystal plane selectivity and limited film continuity. The grain orientation on the surface of polycrystalline copper is complex, making it difficult for graphene to nucleate and grow simultaneously on different grains, easily forming island structures with poor continuity and uniformity. (3) Weak interfacial bonding and easy peeling. The interaction between graphene and copper formed by the traditional growth method is mainly van der Waals interaction, with insufficient interfacial bonding, and delamination is easy to occur during subsequent processing. (4) Lack of effective means of interfacial environment control. Existing overlay growth or weak confinement methods are difficult to stably control the interface space, carbon source concentration and diffusion behavior, making it difficult to achieve large-area preparation of highly oriented, high-quality composite structures.
[0003] Therefore, there is an urgent need for a new preparation process with a clear interface confinement control mechanism to achieve a graphene-copper composite structure with high orientation, high integrity and excellent interfacial bonding, so as to provide key basic material technology for electronic packaging, heat dissipation interconnection and high-end electrical materials. Summary of the Invention
[0004] To address the aforementioned shortcomings, the present invention aims to propose a method for preparing a highly oriented graphene-copper composite structure, thereby solving the problems of random graphene orientation, weak interfacial bonding, and difficulty in large-area uniform growth in existing graphene-copper composite materials.
[0005] To achieve this objective, the present invention adopts the following technical solution: A method for preparing a highly oriented graphene-copper composite structure includes the following steps: (1) Copper substrate pretreatment: mechanical polishing and annealing of copper foil or copper plate to form preferred crystal surfaces; (2) Constructing an interface confinement structure: depositing or attaching a confinement layer on the copper surface, wherein the confinement layer and the copper surface form a confined space; (3) Graphene growth under interface confinement: Under CVD process conditions, carbon source is introduced into confined space, so that graphene grows preferentially on copper surface and forms a highly oriented continuous film. (4) Removal of confinement layer: The confinement layer is removed by wet etching or mechanical stripping to obtain a highly oriented graphene-copper composite structure; (5) Optional post-treatment: Low-temperature annealing or hot pressing of the composite structure to enhance the interfacial bonding force.
[0006] 2. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that the copper substrate pretreatment includes annealing at 900–1050 °C for 30–90 min to obtain Cu(111) or Cu(100) preferred crystal orientation.
[0007] Preferably, the confinement layer is selected from Al2O3, SiO2, a peelable metal film, or a quartz sheet, and has a thickness of 5–50 nm.
[0008] Preferably, the CVD growth conditions include a temperature of 1000–1060 °C, a pressure of 1–500 Pa, and a carbon source selected from CH4, C2H2, or C2H4.
[0009] Preferably, the graphene growth time is 5–30 minutes, and the confined space is kept closed or semi-open during the growth process to limit the diffusion direction of carbon atoms.
[0010] Furthermore, the method for preparing the highly oriented graphene-copper composite structure according to claim 1 is characterized in that the post-treatment includes low-temperature annealing (200–400 °C, 30–120 min) or hot pressing (150–300 °C, 1–10 MPa) to enhance the interfacial bonding force of graphene-copper.
[0011] Furthermore, a double-sided confinement structure is adopted, forming confinement spaces on the upper and lower surfaces of copper respectively, to achieve the growth of double-sided highly oriented graphene.
[0012] Furthermore, by controlling the thickness of the confinement layer, the orientation of the copper crystal plane, and the carbon source flux, single-layer or double-layer graphene structures can be achieved.
[0013] Furthermore, the prepared graphene-copper composite structure has a grain orientation concentrated within ±10°, a conductivity ≥ 101% IACS, and an interface exfoliation force improved by 2–5 times.
[0014] One of the above technical solutions includes the following beneficial effects: 1. Achieving high orientation growth of graphene. By constructing an interface confinement space and controlling the surface energy gradient, the present invention enables graphene to nucleate in a directional manner within the confined interface, thereby significantly improving the uniformity of grain orientation and avoiding problems such as random orientation and polycrystalline splicing in conventional CVD.
[0015] 2. Significantly enhances interfacial bonding. The confined structure inhibits graphene wrinkling and delamination, promoting the formation of a more stable interfacial structure with the copper substrate, resulting in a significant improvement in interfacial bonding compared to traditional growth methods.
[0016] 3. Reducing defect density and improving electrical performance: The confined environment can suppress carbon source supersaturation and control nucleation density, thereby obtaining graphene films with low defects and high integrity, making the key properties of the composite material such as conductivity and sheet resistance significantly better than existing technologies.
[0017] 4. The process is highly controllable and has good compatibility with existing processes. The confinement layer of this invention can be constructed by ALD, sputtering, electroplating, etc. The overall process can be seamlessly integrated with mature technologies such as conventional copper foil annealing, CVD growth, and wet etching, which is convenient for large-scale production. Attached Figure Description
[0018] Figure 1 This is a flowchart illustrating a method according to an embodiment of the present invention. Detailed Implementation
[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0020] 1. A method for preparing a highly oriented graphene-copper composite structure, characterized by comprising the following steps: (1) Copper substrate pretreatment: mechanical polishing and annealing of copper foil or copper plate to form preferred crystal surfaces; (2) Constructing an interface confinement structure: depositing or attaching a confinement layer on the copper surface, wherein the confinement layer and the copper surface form a confined space; (3) Graphene growth under interface confinement: Under CVD process conditions, carbon source is introduced into confined space, so that graphene grows preferentially on copper surface and forms a highly oriented continuous film. (4) Removal of confinement layer: The confinement layer is removed by wet etching or mechanical stripping to obtain a highly oriented graphene-copper composite structure; (5) Optional post-treatment: Low-temperature annealing or hot pressing of the composite structure to enhance the interfacial bonding force.
[0021] The solution has the following effects: it achieves highly oriented growth of graphene. By constructing an interface confinement space and controlling the surface energy gradient, the present invention enables graphene to nucleate in a directional manner within the confined interface, thereby significantly improving the uniformity of grain orientation and avoiding problems such as random orientation and polycrystalline splicing in conventional CVD.
[0022] Significantly enhances interfacial bonding; the confined structure suppresses graphene wrinkling and delamination, promoting the formation of a more stable interfacial structure with the copper substrate, resulting in a significantly improved interfacial bonding compared to traditional growth methods.
[0023] By reducing defect density and improving electrical properties, the confined environment can suppress carbon source supersaturation and control nucleation density, thereby obtaining graphene films with low defects and high integrity. This makes the key properties of the composite material, such as conductivity and sheet resistance, significantly better than existing technologies.
[0024] The process is highly controllable and has good compatibility with existing processes. The confinement layer of this invention can be constructed by ALD, sputtering, electroplating, etc. The overall process can be seamlessly integrated with mature technologies such as conventional copper foil annealing, CVD growth, and wet etching, which is convenient for large-scale production.
[0025] Furthermore, the copper matrix pretreatment includes annealing at 900–1050 °C for 30–90 min to obtain a preferred Cu(111) or Cu(100) crystal orientation.
[0026] Furthermore, the confinement layer is selected from Al2O3, SiO2, peelable metal film or quartz sheet, and has a thickness of 5–50 nm.
[0027] Furthermore, the CVD growth conditions include a temperature of 1000–1060 °C, a pressure of 1–500 Pa, and a carbon source selected from CH4, C2H2, or C2H4.
[0028] Furthermore, the graphene growth time is 5–30 minutes, and the confined space is kept closed or semi-open during the growth process to restrict the diffusion direction of carbon atoms.
[0029] Further post-treatment includes low-temperature annealing (200–400 °C, 30–120 min) or hot pressing (150–300 °C, 1–10 MPa) to enhance the graphene-copper interface bonding.
[0030] Furthermore, a double-sided confinement structure is adopted, forming confinement spaces on the upper and lower surfaces of copper respectively, to achieve the growth of double-sided highly oriented graphene.
[0031] Furthermore, by controlling the thickness of the confinement layer, the orientation of the copper crystal plane, and the carbon source flux, single-layer or double-layer graphene structures can be achieved.
[0032] Furthermore, the prepared graphene-copper composite structure has a grain orientation concentrated within ±10°, a conductivity ≥ 101% IACS, and an interface exfoliation force improved by 2–5 times.
[0033] The technical solution is as follows: (a) Copper substrate pretreatment Mechanical polishing, electrochemical deoxidation, and annealing of copper foil or copper plate (thickness 10–500 μm) are performed to form a high proportion of Cu(111) or Cu(100) crystal orientation on the copper surface.
[0034] (II) Preparation steps Step 1: Construct the interface domain structure Depositing or attaching a peelable confinement layer on the copper surface, including but not limited to: A thin layer of SiO2 (5–50 nm), or a thin layer of Al2O3, or a confined quartz sheet, a peelable metal film, or a graphene transfer layer is used as the upper interface. A copper / confined layer clamping structure is formed, allowing graphene to nucleate and diffuse within a local space.
[0035] Step 2: CVD growth of graphene under interface confinement The confined structure is placed in a CVD furnace, using methane, acetylene, or ethylene as the carbon source and H2 / Ar as the reaction atmosphere.
[0036] Annealing: 1000–1060 ℃, H2 200–400 sccm Growth: 1030 ℃, CH4 5–50 sccm, H2 100–300 sccm Pressure: 1–500 Pa In an interface-confined environment, graphene nucleation is spatially restricted, preferentially growing along high-index copper crystal planes to achieve highly oriented and continuous distribution.
[0037] Step 3: Remove the confinement layer and obtain the composite structure After cooling the sample, the confinement layer can be removed by wet etching or mechanical exfoliation to obtain a highly oriented graphene / copper composite structure.
[0038] Step 4: Optional subsequent densification / diffusion control treatment Includes: low-temperature annealing (200–400 ℃, 30–120 min) to enhance interfacial bonding; Hot pressing densification (150–300 ℃, 1–10 MPa); Surface passivation treatment inhibits oxidation.
[0039] 2. Examples Example 1: Preparation of highly oriented graphene copper foil under interface confinement 1. Copper substrate preparation 25 μm electrolytic copper foil was selected, mechanically polished, and then annealed at 1030 ℃ in H2 atmosphere for 60 min to obtain an orientation rate of about 85% Cu(111).
[0040] 2. Construction of confined domain structure A 10 nm Al2O3 layer was deposited using ALD to confine it to the copper surface.
[0041] 3. Graphene growth CVD temperature: 1035 ℃, CH4 flow rate: 10 sccm, H2: 200 sccm, pressure: 35 Pa, time: 15 min 4. Removal of confined layers Al2O3 was removed using buffered oxide etchant (BOE) to obtain highly oriented monolayer graphene.
[0042] 5. Results Graphene grain orientation is concentrated within ±7°; sheet resistance is reduced by 18%; The interfacial bonding strength with the copper substrate was increased by 3 times; the conductivity reached 102.3% IACS. Example 2: Achieving a highly oriented graphene-copper composite structure through metal sandwich confinement. 1. Copper substrate preparation A 50 μm thick high-purity oxygen-free copper strip was selected, polished sequentially with 800#~3000# sandpaper, and then annealed at 1020℃ in a H2 / Ar (1:4) mixed atmosphere for 45 min to increase the Cu(111) crystal orientation rate to about 78%.
[0043] 2. Construction of confined domain structure A 30 nm Cu–Ni alloy thin layer was deposited on a copper surface using magnetron sputtering. The lattice constant of this interlayer is slightly smaller than that of the copper substrate, which can form a micro-confined space and induce the directional nucleation of graphene.
[0044] 3. Graphene growth conditions (interface-confined CVD) CVD temperature: 1040 ℃, CH4 flow rate: 8 sccm, H2 flow rate: 150 sccm, total pressure: 50 Pa, growth time: 12 min; In the narrow interface space between the sputtered interlayer and the copper substrate, graphene preferentially grows along the Cu(111) crystal orientation and obtains high orientation.
[0045] 4. Removal of confined layers The Cu–Ni confinement layer was selectively dissolved by wet etching (HNO3 diluted to 1 wt%), while preserving the graphene structure formed at the interface.
[0046] 5. Results The graphene grain orientation is concentrated at ±9°; the sheet resistance is reduced by 15% compared to the unconfined sample; the interfacial peeling force is improved by about 2.6 times; and the overall conductivity of the composite copper strip reaches 101.8% IACS.
[0047] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.
Claims
1. A method for preparing a highly oriented graphene-copper composite structure, characterized in that, Includes the following steps: (1) Copper substrate pretreatment: mechanical polishing and annealing of copper foil or copper plate to form preferred crystal surfaces; (2) Constructing an interface confinement structure: depositing or attaching a confinement layer on the copper surface, wherein the confinement layer and the copper surface form a confined space; (3) Graphene growth under interface confinement: Under CVD process conditions, carbon source is introduced into confined space, so that graphene grows preferentially on copper surface and forms a highly oriented continuous film. (4) Removal of confinement layer: The confinement layer is removed by wet etching or mechanical stripping to obtain a highly oriented graphene-copper composite structure; (5) Optional post-treatment: Low-temperature annealing or hot pressing of the composite structure to enhance the interfacial bonding force.
2. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, The copper substrate pretreatment includes annealing at 900–1050 °C for 30–90 min to obtain a preferred Cu(111) or Cu(100) crystal orientation.
3. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, The confinement layer is selected from Al2O3, SiO2, peelable metal thin film or quartz sheet, and has a thickness of 5–50 nm.
4. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, CVD growth conditions include a temperature of 1000–1060 ℃, a pressure of 1–500 Pa, and a carbon source selected from CH4, C2H2, or C2H4.
5. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, The growth time for graphene is 5–30 minutes. During the growth process, the confined space is kept closed or semi-open to limit the diffusion direction of carbon atoms.
6. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, Post-treatment includes low-temperature annealing (200–400 °C, 30–120 min) or hot pressing (150–300 °C, 1–10 MPa) to enhance the graphene-copper interface bonding.
7. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, By employing a double-sided confinement structure, confinement spaces are formed on the upper and lower surfaces of copper, enabling the growth of double-sided highly oriented graphene.
8. The method according to claim 1, characterized in that, By controlling the thickness of the confinement layer, the orientation of the copper crystal plane, and the carbon source flux, single-layer or double-layer graphene structures can be achieved.
9. The method for preparing the highly oriented graphene-copper composite structure according to claim 1, characterized in that, The prepared graphene-copper composite structure has a grain orientation concentrated within ±10°, conductivity ≥ 101% IACS, and interfacial exfoliation force improved by 2–5 times.