Preparation method of high-conductivity polycrystalline copper wire

Abstract

The invention relates to a preparation method of a high-conductivity polycrystalline copper wire, which comprises the following steps: S1, placing a polycrystalline copper wire with the diameter of 50-2000 microns in a chemical vapor deposition system, and growing a graphene film on the surface of the polycrystalline copper wire at the growth temperature of 350-650 DEG C; and S2, packaging the polycrystalline copper wire on which the graphene film grows by using metal to form a packaging metal layer, thereby preparing the high-conductivity polycrystalline copper wire. According to the method, preparation of the ultrahigh-conductivity copper wire is achieved, the application field of the copper wire can be expanded, and the method has great significance in achieving wide application of the copper wire in the field of microelectronics.

Description

Technical Field

[0001] The invention belongs to the field of conductive materials, and in particular relates to a method for preparing a highly conductive polycrystalline copper wire. Background Art

[0002] Copper metal boasts high ductility, high electrical and thermal conductivity, stability, and machinability, making it widely used in the power and communications industries. However, in specialized signal applications, such as signal transmission, conductor conductivity is highly demanding. Research has shown that signal fidelity is positively correlated with conductor conductivity, making improving conductor conductivity a crucial approach to enhancing signal fidelity. Currently, the main methods for increasing metal conductivity include metal purification, single crystallization, and element doping. Metal purification and single crystallization have reached their physical limits and are difficult to improve. While element doping can improve conductivity to a certain extent, its stability is poor. These traditional methods have limited effectiveness in improving the conductivity of metal conductors. Graphene, a two-dimensional material with exceptionally high mechanical and electrical properties, is an ideal reinforcement for metal composites. Research has shown that graphene and copper metal can form complementary materials and effectively dope copper.

[0003] Existing technologies for preparing graphene-copper composite materials primarily involve the following: Graphene powder is physically or chemically combined with a metal, and the metal is then subjected to post-processing processes such as hot pressing and cold drawing to produce copper wire. While the graphene-copper wire obtained using this method exhibits improved strength and thermal conductivity, its electrical conductivity is not. This is primarily due to the fact that the graphene powder is fragmented and discontinuous within the copper wire. Furthermore, the interfacial contact between the graphene and the copper matrix is ​​relatively poor, preventing the graphene from providing an effective electron transport channel for the copper matrix and effectively interdoping with it to improve conductivity. Another method involves coating the graphene powder onto the surface of a copper wire from a solution. While this method can effectively improve the thermal conductivity of the wire, it struggles to improve its electrical conductivity due to issues such as the fragmentation of the graphene film and poor interfacial bonding between the graphene and the wire. Patent CN111058017A currently discloses a method for low-temperature plasma-assisted chemical vapor deposition of materials, which continuously grows graphene-metal composite wires on the surface of a metal wire. While this method can effectively address the issues of graphene continuity and interfacial bonding, it also addresses the issues of graphene continuity and interfacial bonding. However, due to the need for reel-to-reel mechanical transmission, the wire strength requirements are relatively high, which easily leads to wire breakage and limits its application range. Therefore, how to prepare high-conductivity graphene-copper composite wires of arbitrary diameters is currently an urgent problem to be solved. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a highly conductive polycrystalline copper wire, thereby solving the problem of signal transmission loss caused by high resistance of the signal transmission line in the prior art.

[0005] The present invention provides a method for preparing a high-conductivity polycrystalline copper wire, comprising the following steps:

[0006] S1. Place a polycrystalline copper wire with a diameter of 50 to 2000 μm in a chemical vapor deposition system and grow a graphene film on the surface of the copper wire at a growth temperature of 350 to 650°C;

[0007] S2. The polycrystalline copper wire grown with the graphene film is packaged with a metal to form a packaging metal layer, thereby producing a highly conductive polycrystalline copper wire.

[0008] Preferably, the growth temperature in step S1 is 500-650°C.

[0009] Preferably, the graphene film in step S1 is 1 to 4 layers of graphene.

[0010] More preferably, the graphene film is 1 to 3 layers of graphene.

[0011] Furthermore, the graphene film is a continuous film.

[0012] Preferably, the carbon source for growing the graphene film in step S1 includes one or a combination of methane, ethylene or acetylene.

[0013] Preferably, the metal in step S2 includes but is not limited to copper, nickel or iron, or a combination of several of them.

[0014] Preferably, the thickness of the packaging metal layer in step S2 is 3 to 200 nm.

[0015] More preferably, the thickness of the packaging metal layer is 50-100 nm.

[0016] Beneficial effects

[0017] (1) The present invention grows graphene at low temperature. Under such conditions, the graphene grown has more atomic-level defects, which can better enhance the close bonding between graphene and copper and improve the conductivity of polycrystalline copper wire.

[0018] (2) The present invention uses metal to encapsulate the polycrystalline copper wire grown with graphene, which not only improves the conductivity of the copper wire, but also ensures the stability of the conductivity.

[0019] (3) The method for preparing highly conductive polycrystalline copper wires of the present invention is beneficial for expanding the application fields of copper wires and has important significance for realizing the widespread application of copper wires in the field of microelectronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a macroscopic image of the highly conductive polycrystalline copper wire in Example 1 of the present invention.

[0021] Figure 2 This is an SEM image of the polycrystalline copper wire after graphene film growth in Example 1 of the present invention.

[0022] Figure 3 This is a Raman graph of the graphene film grown on the surface of the polycrystalline copper wire in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0024] Example 1

[0025] The method for preparing a highly conductive polycrystalline copper wire in this embodiment includes the following steps:

[0026] A section of polycrystalline copper wire with a diameter of 50 microns was cleaned with dilute hydrochloric acid, purified water, and isopropyl alcohol, then placed in a chemical vapor deposition system. Graphene was grown on the surface of the polycrystalline copper wire at a temperature of 500°C for 30 minutes, resulting in a 1-2-layer graphene film. The copper wire with the graphene film was then encapsulated with a 50-nanometer-thick layer of metallic copper to produce a highly conductive polycrystalline copper wire. Electrical measurements of the copper wire revealed a conductivity of 112% IACS.

[0027] Figure 1 This is a macroscopic image of the highly conductive polycrystalline copper wire prepared in this example. Figure 2 This is the SEM image of the graphene film grown on the surface of the polycrystalline copper wire. The SEM image shows that the grown graphene is relatively uniform; Figure 3 Its Raman graph shows that graphene has a high degree of crystallinity.

[0028] Example 2

[0029] The method for preparing the highly conductive polycrystalline copper wire in this example is similar to that in Example 1, except that the graphene growth temperature was 650°C. The resulting graphene film consisted of one to two graphene layers. Electrical measurements of the resulting highly conductive polycrystalline copper wire revealed a conductivity of 114% IACS.

[0030] Example 3

[0031] The method for preparing the highly conductive polycrystalline copper wire in this example is similar to that in Example 1, except that the graphene growth temperature was 350°C. The resulting graphene film consisted of one to two graphene layers. Electrical measurements of the resulting highly conductive polycrystalline copper wire revealed a conductivity of 102% IACS.

[0032] Example 4

[0033] The method for preparing the high-conductivity polycrystalline copper wire in this embodiment is similar to that in Example 1, except that the metal encapsulation layer is 100 nanometers thick copper. Electrical measurements of the prepared high-conductivity polycrystalline copper wire revealed a conductivity of 116% IACS.

[0034] Example 5

[0035] The method for preparing the high-conductivity polycrystalline copper wire in this embodiment is similar to that in Example 1, except that the metal encapsulation layer is 3 nanometers thick copper. Electrical measurements of the prepared high-conductivity polycrystalline copper wire revealed a conductivity of 101.3% IACS.

[0036] Example 6

[0037] The method for preparing the highly conductive polycrystalline copper wire in this example is similar to that in Example 1, except that the polycrystalline copper wire has a diameter of 2000 microns and the metal encapsulation layer is 3 nanometers thick copper. Electrical measurements of the resulting highly conductive polycrystalline copper wire revealed a conductivity of 100.4% IACS.

[0038] Table 1 shows the electrical conductivity results of the highly conductive polycrystalline copper wires prepared in Examples 1 to 6. The method of the present invention grows graphene at low temperatures. The graphene grown under these conditions has more atomic-level defects, which can better enhance the close bonding between graphene and copper, thereby improving the conductivity of the polycrystalline copper wire.

[0039] Table 1 Electrical conductivity of high conductive copper wires prepared in Examples 1 to 6

[0040] Example 1 2 3 4 5 6 Conductivity (IACS) 112％ 114％ 102％ 116％ 101.3％ 100.4％

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various modifications are possible. In other words, any simple, equivalent changes and modifications made in accordance with the claims and description of the present invention are within the scope of protection of the patent claims. Anything not fully described in this invention constitutes conventional technology.

Claims

1. A method for preparing a highly conductive polycrystalline copper wire, comprising the following steps: S1. Place a polycrystalline copper wire with a diameter of 50 to 2000 μm in a chemical vapor deposition system and grow a graphene film on the surface of the copper wire at a growth temperature of 350 to 650°C; S2. The polycrystalline copper wire grown with the graphene film is packaged with a metal to form a packaging metal layer, thereby producing a highly conductive polycrystalline copper wire.

2. The method for preparing a high-conductivity polycrystalline copper wire according to claim 1, wherein: The growth temperature in step S1 is 500-650°C.

3. The method for preparing a high-conductivity polycrystalline copper wire according to claim 1, wherein: The graphene film in step S1 is 1 to 4 layers of graphene.

4. The method for preparing a high-conductivity polycrystalline copper wire according to claim 1, wherein: The carbon source for growing the graphene film in step S1 includes one or a combination of methane, ethylene or acetylene.

5. The method for preparing a high-conductivity polycrystalline copper wire according to claim 1, wherein: The metal in step S2 includes one or a combination of copper, nickel or iron.

6. The method for preparing a high-conductivity polycrystalline copper wire according to claim 1, wherein: The thickness of the packaging metal layer in step S2 is 3 to 200 nm.

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