Silicon carbide fiber-copper composite bonding wire and preparation method thereof

Abstract

The invention provides a silicon carbide fiber-copper composite bonding wire and a preparation method thereof, and relates to the technical field of electronic materials. The preparation method of the silicon carbide fiber-copper composite bonding wire comprises the following steps: pre-plating copper on the surface of silicon carbide fiber to obtain copper-coated silicon carbide fiber; laying copper-coated silicon carbide fibers to obtain a copper-coated silicon carbide fiber layer, then constructing a copper alloy layer on the copper-coated silicon carbide fiber layer by using composite copper powder, then arranging the copper-coated silicon carbide fiber layer on the surface of the copper alloy layer again, and repeating the operation to obtain a composite wire blank in which the copper-coated silicon carbide fiber layers and the copper alloy layers are alternately arranged; and sequentially carrying out hot isostatic pressing treatment, drawing and aging treatment on the composite wire blank to obtain the silicon carbide fiber-copper composite bonding wire. The copper powder further comprises Ag, Hf and Sc, the metal elements can form fine and dispersed second-phase particles in the preparation process, and the strength of the copper bonding wire is remarkably improved through a precipitation strengthening mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic materials, and in particular to a silicon carbide fiber-copper composite bonding wire and a preparation method thereof. Background Art

[0002] With the rapid advancement of electronic technology, performance requirements for electronic devices such as integrated circuits are constantly increasing. As a key material for achieving electrical connections in electronic packaging, copper bonding wires must possess higher strength and conductivity to withstand increasingly demanding operating environments. Traditional copper bonding wires have limitations in balancing strength and conductivity, making them difficult to meet the current and future trends in miniaturization and higher performance in electronic devices. Existing technologies improve copper bonding wire performance by adding alloying elements, but this suffers from issues such as insufficient strengthening and significant impact on conductivity. Conventional methods such as roller drawing also struggle to precisely control the microstructure and properties of the bonding wires. Furthermore, the application of additive manufacturing technology in copper bonding wire production is still immature, failing to fully leverage its advantages in material composites and structural design. Therefore, the development of a novel high-strength, high-conductivity copper bonding wire and its preparation method are of great practical significance. Summary of the Invention

[0003] The purpose of the present invention is to provide a silicon carbide fiber-copper composite bonding wire and a preparation method thereof, so as to solve the problem that existing bonding wires have certain limitations in balancing strength and conductivity, and are difficult to meet the current and future development trend of miniaturization and high performance of electronic devices.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing a silicon carbide fiber-copper composite bonding wire, comprising the following steps: 1) Pre-plating copper on the surface of silicon carbide fiber to obtain copper-coated silicon carbide fiber; 2) Laying copper-coated silicon carbide fibers to obtain a copper-coated silicon carbide fiber layer, then using composite copper powder to construct a copper alloy layer on the copper-coated silicon carbide fiber layer, and then again placing a copper-coated silicon carbide fiber layer on the surface of the copper alloy layer. Repeating the operation to obtain a composite wire blank with alternating copper-coated silicon carbide fiber layers and copper alloy layers; 3) The composite wire blank is subjected to hot isostatic pressing, drawing and aging treatment in sequence to obtain a silicon carbide fiber-copper composite bonding wire; The composite copper powder in step 2) comprises the following elements in mass fractions: Ag 0.05-0.2wt%, Hf 0.01-0.05wt%, Sc 0.005-0.02wt%, and the balance copper.

[0005] Preferably, the diameter of the silicon carbide fiber in step 1) is 0.03-0.15 mm, and the single-filament tensile strength is 3-5 GPa.

[0006] Preferably, the copper pre-plating method in step 1) is chemical plating and / or vapor deposition; The thickness of the pre-copper plating is 0.005-0.02 mm.

[0007] Preferably, the method for constructing the alloy copper layer in step 2) is a powder bed fusion method; The particle size of the composite copper powder is 10-50 μm.

[0008] Preferably, in step 2), the radial thickness of each copper-coated silicon carbide fiber layer is independently 0.1-0.2 mm, and the radial thickness of each copper alloy layer is independently 0.1-0.3 mm; The radial thickness of the composite wire blank is 1-3 mm.

[0009] Preferably, the hot isostatic pressing treatment in step 3) is performed at a temperature of 800-1000° C., a pressure of 100-200 MPa, and a time of 1-3 h.

[0010] Preferably, the deformation rate of the drawing process in step 3) is 0.1-0.5 mm / s, and the temperature of the drawing process is 100-200° C.; The diameter of the silicon carbide fiber-copper composite bonding wire is 0.05-0.1 mm.

[0011] Preferably, the aging treatment in step 3) is performed at a temperature of 450-550° C. and for a time of 2-4 hours.

[0012] The present invention also provides a silicon carbide fiber-copper composite bonding wire prepared by the above preparation method.

[0013] The present invention has at least the following beneficial effects: The present invention introduces silver, hafnium and scandium elements in the process of preparing silicon carbide fiber-copper composite bonding wire. Among them, silver can improve the strength and conductivity of copper. Hafnium and scandium have low solid solubility in copper and can form fine and dispersed second-phase particles such as HfCu5 and ScCu2 during the aging process. The strength of the copper bonding wire is significantly improved through the precipitation strengthening mechanism, and the conductivity is less affected.

[0014] High-strength silicon carbide (SiC) fiber with good compatibility with copper is selected as the reinforcing wire. Its diameter is 0.03~0.15mm, and the tensile strength of the single wire can reach 3~5GPa, which can provide excellent reinforcement effect for the bonding wire. The radial thickness of the copper layer is 0.08~0.25mm, ensuring good conductivity while not excessively increasing the overall size. During the subsequent drawing process, the plastic phase (Cu layer) on the surface of the silicon carbide fiber forms a composite material to disperse stress, inhibit the propagation of silicon carbide cracks, and drive the internal SiC cooperative deformation. The annealing treatment after each drawing pass can eliminate the internal stress of the silicon carbide fiber and repair the micro-damage on its surface, and finally prepare a silicon carbide fiber-copper composite bonding wire with a single wire diameter of 0.05~0.1mm. DETAILED DESCRIPTION

[0015] The present invention provides a method for preparing a silicon carbide fiber-copper composite bonding wire, comprising the following steps: 1) Pre-plating copper on the surface of silicon carbide fiber to obtain copper-coated silicon carbide fiber; 2) Laying copper-coated silicon carbide fibers to obtain a copper-coated silicon carbide fiber layer, then using composite copper powder to construct a copper alloy layer on the copper-coated silicon carbide fiber layer, and then again placing a copper-coated silicon carbide fiber layer on the surface of the copper alloy layer. Repeating the operation to obtain a composite wire blank with alternating copper-coated silicon carbide fiber layers and copper alloy layers; 3) The composite wire blank is subjected to hot isostatic pressing, drawing and aging treatment in sequence to obtain a silicon carbide fiber-copper composite bonding wire; The composite copper powder in step 2) comprises the following elements in mass fraction: Ag 0.05-0.2wt%, Hf 0.01-0.05wt%, Sc 0.005-0.02wt%, and the balance copper, preferably Ag 0.08-0.18wt%, Hf 0.02-0.04wt%, Sc 0.008-0.018wt%, and the balance copper, further preferably Ag 0.1-0.15wt%, Hf 0.025-0.035wt%, Sc 0.01-0.015wt%, and the balance copper, more preferably Ag 0.12-0.13wt%, Hf 0.03wt%, Sc 0.012-0.013wt%, and the balance copper.

[0016] In the present invention, the silicon carbide fiber in step 1) further includes a pretreatment step before being plated with a copper layer. The pretreatment method is to use HF to pickle the silicon carbide fiber to remove impurities and oxides on the surface of the silicon carbide fiber and improve its wettability with copper.

[0017] In the present invention, the diameter of the silicon carbide fiber in step 1) is 0.03~0.15 mm, preferably 0.05~0.13 mm, more preferably 0.07~0.11 mm, and more preferably 0.09~0.1 mm; the single fiber tensile strength is 3~5 GPa, preferably 3.2~4.8 GPa, more preferably 3.5~4.5 GPa, and more preferably 3.8~4.2 GPa.

[0018] In the present invention, the copper pre-plating method in step 1) is chemical plating and / or vapor deposition; In the present invention, the thickness of the pre-copper plating is 0.005-0.02 mm, preferably 0.008-0.018 mm, more preferably 0.01-0.015 mm, and even more preferably 0.012-0.013 mm.

[0019] In the present invention, the method for constructing the alloy copper layer in step 2) is a powder bed fusion method, and the powder bed fusion method preferably uses a laser beam or an electron beam to melt the composite copper powder.

[0020] In the present invention, the particle size of the composite copper powder is 10-50 μm, preferably 15-45 μm, more preferably 20-40 μm, and even more preferably 25-35 μm.

[0021] In the present invention, the radial thickness of each copper-clad silicon carbide fiber layer in step 2) is independently 0.1~0.2mm, preferably 0.12~0.18mm, further preferably 0.14~0.16mm, and more preferably 0.15mm; the radial thickness of each copper alloy layer is independently 0.1~0.3mm, preferably 0.13~0.28mm, further preferably 0.15~0.25mm, and more preferably 0.18~0.22mm.

[0022] In the present invention, the radial thickness of the composite wire blank is 1-3 mm, preferably 1.3-2.8 mm, more preferably 1.5-2.5 mm, and even more preferably 1.8-2.2 mm.

[0023] In the present invention, the copper alloy layer and the copper-clad silicon carbide fiber layer in the composite wire billet are coaxially coated.

[0024] In the present invention, the temperature of the hot isostatic pressing treatment in step 3) is 800~1000°C, preferably 830~980°C, more preferably 850~950°C, and more preferably 880~920°C; the pressure is 100~200MPa, preferably 120~180MPa, more preferably 140~160MPa, and more preferably 150MPa; the time is 1~3h, preferably 1.5~2.5h, more preferably 1.75~2.25h, and more preferably 2h; the hot isostatic pressing treatment under high temperature and high pressure environment can eliminate the internal porosity of the composite wire billet, improve the material density, and further enhance the bonding force between copper and silicon carbide fiber.

[0025] In the present invention, the deformation rate of the drawing treatment in step 3) is 0.1-0.5 mm / s, preferably 0.2-0.4 mm / s, more preferably 0.25-0.35 mm / s, and more preferably 0.3 mm / s; the temperature of the drawing treatment is 100-200°C, preferably 120-190°C, more preferably 140-180°C, and more preferably 160-170°C.

[0026] In the present invention, the diameter of the silicon carbide fiber-copper composite bonding wire is 0.05-0.1 mm, preferably 0.06-0.09 mm, and more preferably 0.07-0.08 mm.

[0027] In the present invention, the aging treatment temperature in step 3) is 450-550°C, preferably 470-530°C, more preferably 490-510°C, and more preferably 500°C; the aging treatment time is 2-4 hours, preferably 2.5-3.5 hours, more preferably 2.75-3.25 hours, and more preferably 3 hours. The aging treatment can promote the sufficient precipitation and dispersion of the second phase particles formed by hafnium and scandium, thereby improving the strength of the bond wire.

[0028] The present invention also provides a silicon carbide fiber-copper composite bonding wire prepared by the above preparation method.

[0029] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0030] Example 1

[0031] 1) Silicon carbide fibers with a cross-sectional diameter of 0.1 mm and a single-filament tensile strength of 4.0 GPa were pickled with hydrofluoric acid and then coated with a copper layer with a radial thickness of 0.012 mm (the surface roughness of the copper layer Ra ≤ 1.5 μm) by chemical plating to obtain copper-coated silicon carbide fibers.

[0032] 2) Silicon carbide fiber with copper coating prepared in step 1) and composite copper powder (Ag 0.12wt%, Hf 0.03wt%, Sc 0.012wt%, balance Cu, particle size 30μm, bulk density 4.8g / cm 3 ) is used as raw material to prepare composite wire blanks, and the specific preparation method is as follows: A single pre-coated copper-silicon carbide fiber (0.124 mm in diameter) was used as the central core. Laser powder bed fusion (LPBF) was used to deposit an annular copper alloy layer around the core fiber. The laser power was 400 W, the scanning speed was 600 mm / s, the powder layer thickness was 30 μm, the scanning pitch was 0.08 mm, and the inter-layer rotation was 67°. The resulting copper alloy layer had a radial thickness of 0.2 mm and a total diameter after deposition of 0.124 + 2 × 0.2 = 0.524 mm. The pre-coated copper-silicon carbide fiber was then tightly wound around the copper alloy layer to form an annular fiber layer with a radial thickness of 0.15 mm. The total diameter after winding was 0.524 + 2 × 0.15 = 0.824 mm.

[0033] Silicon carbide fiber layers and copper alloy layers were prepared alternately in the above manner. The structure of the final composite wire blank was as follows: core fiber (0.124 mm) → copper alloy ring (0.2 mm) → fiber ring (0.15 mm) → copper alloy ring (0.2 mm), with a total diameter of 1.224 mm.

[0034] 3) The composite wire billet was hot isostatically pressed at 900°C and 150 MPa for 2 h to obtain a composite wire billet with a density of 99.2%; then, the wire billet was drawn at a deformation rate of 0.3 mm / s, and a wire with a diameter of 0.08 mm was obtained after 12 drawing passes (18% surface reduction per pass); finally, the wire obtained after drawing was aged at 500°C, kept warm for 3 h, and then cooled to room temperature with the furnace to obtain a silicon carbide fiber-copper composite bonding wire.

[0035] The performance of the silicon carbide fiber-copper composite bonding wire prepared in this embodiment was tested, and the test results are as follows: Tensile strength: 850 MPa, electrical conductivity: 88% IACS, interface bonding strength: 62 MPa (shear), microstructure: copper alloy layer porosity 0.3%, interface reaction layer radial thickness 0.8 μm.

[0036] Example 2

[0037] 1) After hydrofluoric acid pickling, silicon carbide fibers with a cross-sectional diameter of 0.05 mm and a single-filament tensile strength of 4.5 GPa were coated with a copper layer with a radial thickness of 0.01 mm (the bonding strength between the copper layer and the silicon carbide fiber was ≥80 MPa) by vapor deposition to obtain copper-coated silicon carbide fibers with a diameter of 0.07 mm.

[0038] 2) A composite wire blank was prepared using the copper-coated silicon carbide fiber prepared in step 1) and composite copper powder (Ag 0.15wt%, Hf 0.025wt%, Sc 0.015wt%, balance Cu, particle size 20μm, flowability 28s / 50g) as raw materials. The specific preparation method is as follows: A single pre-coated copper-silicon carbide fiber (0.07 mm diameter) was used as the central core. Electron beam powder bed fusion (EB-PBF) was used to deposit an annular copper alloy layer around the pre-coated copper-silicon carbide fiber. The accelerating voltage was 80 kV, the beam current was 5 mA, the scanning speed was 4000 mm / s, the linear energy was 0.0125 J / mm, the powder layer thickness was 40 μm, and the preheating temperature was 500°C. The resulting copper alloy layer had a radial thickness of 0.2 mm and a total diameter after deposition of 0.47 mm (0.07 + 2 × 0.2 = 0.47 mm). The pre-coated copper-silicon carbide fiber was then tightly wound around the copper alloy layer to form an annular fiber layer with a radial thickness of 0.2 mm, resulting in a total diameter of 0.87 mm.

[0039] The structure of the obtained composite wire blank is: core fiber (0.07 mm) → copper alloy ring (0.2 mm) → fiber ring (0.2 mm), with a total diameter of 1.67 mm.

[0040] 3) The composite wire billet was hot isostatically pressed at 880°C and 160 MPa for 1.5 h to obtain a composite wire billet with a density of 99.5%; then, the wire billet was drawn at a deformation rate of 0.25 mm / s, and a wire with a diameter of 0.06 mm was obtained after 15 drawing passes (each pass with an area reduction rate of 18%); finally, the wire obtained after drawing was aged at 490°C, kept warm for 3.5 h, and then cooled to room temperature with the furnace to obtain a silicon carbide fiber-copper composite bonding wire.

[0041] The performance of the silicon carbide fiber-copper composite bonding wire prepared in this embodiment was tested, and the test results are as follows: Tensile strength: 920MPa, electrical conductivity: 85% IACS, interfacial bonding strength: 68MPa (shear), 10 6 The cyclic loading life of pure copper bonding wire of the same size is 10 5 Second-rate.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a silicon carbide fiber-copper composite bonding wire, characterized in that: The following steps are involved: 1) Pre-plating copper on the surface of silicon carbide fiber to obtain copper-coated silicon carbide fiber; 2) Laying copper-coated silicon carbide fibers to obtain a copper-coated silicon carbide fiber layer, then using composite copper powder to construct a copper alloy layer on the copper-coated silicon carbide fiber layer, and then again placing a copper-coated silicon carbide fiber layer on the surface of the copper alloy layer. Repeating the operation to obtain a composite wire blank with alternating copper-coated silicon carbide fiber layers and copper alloy layers; 3) The composite wire blank is subjected to hot isostatic pressing, drawing and aging treatment in sequence to obtain a silicon carbide fiber-copper composite bonding wire; The composite copper powder in step 2) comprises the following elements in mass fractions: Ag 0.05-0.2wt%, Hf 0.01-0.05wt%, Sc 0.005-0.02wt%, and the balance copper.

2. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 1, characterized in that: The diameter of the silicon carbide fiber in step 1) is 0.03-0.15 mm, and the tensile strength of the single fiber is 3-5 GPa.

3. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 2, characterized in that: The copper pre-plating method in step 1) is chemical plating and / or vapor deposition; The thickness of the pre-copper plating is 0.005-0.02 mm.

4. The method for preparing a silicon carbide fiber-copper composite bonding wire according to any one of claims 1 to 3, characterized in that: The method for constructing the alloy copper layer in step 2) is a powder bed fusion method; The particle size of the composite copper powder is 10-50 μm.

5. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 4, characterized in that: In step 2), the radial thickness of each copper-coated silicon carbide fiber layer is independently 0.1-0.2 mm, and the radial thickness of each copper alloy layer is independently 0.1-0.3 mm; The radial thickness of the composite wire blank is 1-3 mm.

6. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 5, characterized in that: The hot isostatic pressing treatment in step 3) is performed at a temperature of 800-1000° C., a pressure of 100-200 MPa, and a time of 1-3 hours.

7. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 6, characterized in that: The deformation rate of the drawing process in step 3) is 0.1-0.5 mm / s, and the temperature of the drawing process is 100-200° C.; The diameter of the silicon carbide fiber-copper composite bonding wire is 0.05-0.1 mm.

8. The method for preparing a silicon carbide fiber-copper composite bonding wire according to claim 6 or 7, characterized in that: The aging treatment in step 3) is performed at a temperature of 450-550° C. for 2-4 hours.

9. A silicon carbide fiber-copper composite bonding wire prepared by the method for preparing a silicon carbide fiber-copper composite bonding wire according to any one of claims 1 to 8.