Gold-plated copper bonding wire and preparation method and application thereof

Abstract

The invention provides a gold-plated copper bonding wire and a preparation method and application thereof, and relates to the technical field of bonding wires. Specifically, the method comprises the following steps: immersing a single crystal copper rod into a gold-tin alloy melt, and then carrying out sizing treatment to obtain a copper rod plated with a gold-tin alloy; then acid leaching treatment is conducted till no bubble is generated, and the tin-removed and gold-plated copper rod is obtained; and then normal-temperature drawing and on-line annealing drawing are sequentially carried out to obtain the gold-plated copper bonding wire. The invention provides a novel gold-plated copper bonding wire production process which is energy-saving, environment-friendly and efficient, has the advantages of high bonding strength of a gold plating layer and copper, uniform and controllable thickness of the plating layer and the like, has remarkable performance in production efficiency and finished product quality, and provides a wide prospect for application of the gold-plated copper bonding wire in electronic packaging.

Description

Technical Field

[0001] The present invention relates to the technical field of bonding wires, and in particular to a gold-plated copper bonding wire and a preparation method and application thereof. Background Art

[0002] As electronic packaging develops towards miniaturization, multi-function and low cost, the packaging industry has put forward higher requirements for packaging forms and packaging materials. Wire bonding is the earliest chip packaging technology, which realizes the interconnection between the device and its package body through metal wires, also known as "bonding wires". Gold is the traditional metal used for bonding wires, but the electrical and thermal conductivity of gold makes its application in high-density and fine-pitch packaging more challenging. At the same time, the cost of gold wires continues to increase, but the prices of products such as LEDs and ICs continue to fall, which has led to the gradual marginalization of gold applications.

[0003] Copper has higher electrical and thermal conductivity than gold, and its cost is much lower than that of gold, making copper widely accepted as a new bonding wire material. However, since copper wire is easily oxidized in the environment, oxidation barrier technology is an important way to solve the problem of bare copper wire being easily oxidized. If gold is used as an oxidation barrier to coat bare copper wire, it will reduce costs while meeting the requirements for anti-oxidation performance.

[0004] Therefore, gold-plated copper wire with good bondability and reliability is expected to become the bonding wire with the greatest potential to replace gold wire. At present, the production of gold-plated copper bonding wire generally adopts electroplating and chemical plating technology. Specifically, copper is continuously cast into wire billets, and the copper bonding wire is electroplated or chemically plated online after rough drawing, medium drawing, and fine drawing. Furthermore, cyanide gold plating has always been the mainstream process in the gold plating industry. It is widely used in gold-plated copper bonding wires due to its stable plating solution, high brightness of the coating, strong bonding ability, high flatness, and strong dispersion ability. However, cyanide gold plating is highly toxic, which not only affects the health of the operators, but also seriously pollutes the environment with the discharged wastewater. If a green and environmentally friendly gold-plated copper bonding wire production process can be developed, it will be expected to expand the use of gold-plated copper bonding wires.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a method for preparing a gold-plated copper bonding wire, which avoids the burden of environmental pollution in conventional electroplating or chemical plating, reduces production costs while improving production efficiency, and has the advantages of energy saving, environmental protection, and high efficiency.

[0007] The second object of the present invention is to provide a gold-plated copper bonding wire having good electrical conductivity, thermal conductivity, oxidation resistance and economy.

[0008] The third object of the present invention is to provide the use of the gold-plated copper bonding wire in packaging.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] A method for preparing a gold-plated copper bonding wire comprises the following steps:

[0011] (1) immersing a single crystal copper rod into a melt of a gold-tin alloy, and then performing a sizing treatment to obtain a copper rod coated with the gold-tin alloy;

[0012] (2) subjecting the copper rod plated with the gold-tin alloy to an acid immersion treatment until no bubbles are generated and a detinned gold-plated copper rod is obtained;

[0013] (3) The detinned gold-plated copper rod is sequentially subjected to room temperature drawing and online annealing drawing to obtain a gold-plated copper bonding wire.

[0014] A gold-plated copper bonding wire is prepared based on the preparation method of the gold-plated copper bonding wire, and a use of the gold-plated copper bonding wire in packaging.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention provides a preparation process route for a gold-plated copper bonding wire, which can effectively solve the defects of high pollution and high cost existing in traditional electroplating or chemical gold plating. The present invention obtains a gold-tin plating layer with high bonding strength by compounding a liquid and semi-solid low-melting-point gold-tin alloy with a single crystal copper rod under certain temperature conditions for chemical metallurgical bonding; further, the tin in the gold-tin alloy layer reacts easily with acid to form SnCl2 and hydrogen and dissolve and remove the tin, thereby obtaining a single crystal copper rod with a gold layer having holes on the surface; and then in the drawing process, the gold layer with holes will be extended by the tensile and compressive stress of the wire drawing die, and the holes will be filled; and in the online annealing wire drawing process, the flaky gold layer will be bonded in a high temperature and protective gas atmosphere, thereby obtaining a smooth and evenly distributed gold plating layer on the copper rod surface.

[0017] (2) The gold-plated copper bonding wire provided by the present invention has significant advantages such as high bonding strength between the gold plating layer and the copper rod, uniform and controllable thickness of the gold plating layer, and adjustable cross-sectional area coating ratio, which is conducive to improving the coordination of cold working deformation of gold and copper. Since the present invention can plate a gold layer in the blank state, it is conducive to the control and adjustment of the above-mentioned processing parameters, and the production efficiency is greatly improved; the present invention also adopts an online annealing and drawing process to effectively reduce the number of wire breaks and plating leakage, and further improve the quality of the finished product and production efficiency of the gold-plated bonding wire.

[0018] (3) The preparation method provided by the present invention has the important advantages of energy saving, environmental protection and high production efficiency. Compared with traditional electroplating or chemical gold plating, the bonding wire coating of the present invention is uniform, continuous and dense, and the coating has good bonding strength with the copper core. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a plating device used in the present invention is provided;

[0021] Figure 2 A finished product diagram of Embodiment 1 of the present invention is provided;

[0022] Figure 3 The SEM image of Example 1 of the present invention is provided. DETAILED DESCRIPTION

[0023] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will appreciate that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those who do not specify the manufacturer of the reagents or instruments used are all conventional products that can be purchased commercially. In addition, the terms "one", "two", "1", etc. are only used for descriptive purposes and cannot be interpreted as indicating or implying relative importance.

[0024] The first aspect of the present invention is to provide a method for preparing a gold-plated copper bonding wire, which mainly includes the following three main steps: first, a gold-tin alloy is plated on the surface of a single crystal copper rod; second, the tin is removed by acid etching to obtain a gold-plated layer with holes; and finally, bonding of the gold-plated layer is achieved by two-stage annealing and drawing. Specifically, it includes the following steps (1) to (3).

[0025] (1) A single crystal copper rod is immersed in a melt of a gold-tin alloy, and then a copper rod coated with a gold-tin alloy is obtained by sizing.

[0026] As a preferred implementation manner, the single crystal in the single crystal copper rod means that the copper rod is composed of only one crystal grain, and there is no grain boundary between the crystal grains; the copper purity in the single crystal copper rod is ≥99.999%.

[0027] As an optional embodiment, the diameter of the single crystal copper rod is 1 mm to 8 mm, including but not limited to any one of 1, 2, 3, 4, 5, 6, 7, and 8 (mm) or a numerical range consisting of any two of them; in addition, the thickness of the gold-tin alloy coating layer obtained after the sizing treatment is 0.1 mm to 0.5 mm, including but not limited to any one of 0.1, 0.2, 0.3, 0.4, and 0.5 (mm) or a numerical range consisting of any two of them.

[0028] As a preferred embodiment, before step (1), the method further includes: preparing the gold-tin alloy, comprising the following steps: smelting a high-purity gold block and a high-purity tin block to obtain the gold-tin alloy, wherein the purity of the high-purity gold block and the high-purity tin block are both ≥99.999%; in some optional embodiments, the smelting of the gold-tin alloy is carried out in a vacuum environment.

[0029] As a preferred embodiment, the temperature of the melt of the gold-tin alloy is 300°C to 350°C, including but not limited to any one of 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350 (°C) or a numerical range consisting of any two of them. It is worth noting that based on the temperature of the melt of the gold-tin alloy, the gold-tin alloy is in liquid and semi-solid state, wherein the semi-solid state refers to a solid-liquid mixed slurry in which a certain solid phase component is uniformly suspended in a liquid metal mother liquor by controlling the solid-liquid temperature range during the metal solidification process; this form of mixed slurry has rheological properties, that is, it has good fluidity and is easy to be made into products by ordinary processing methods.

[0030] As a preferred embodiment, excluding extremely small amounts of impurities that are difficult to ignore, the gold-tin alloy includes 19% to 21% tin and 79% to 81% gold by mass. It is understandable that the eutectic component or near-eutectic component of the gold-tin alloy has a low melting temperature, and by controlling the ratio of gold and tin in the gold-tin alloy, a eutectic melt and a high-quality coating layer can be effectively obtained.

[0031] As a preferred embodiment, step (1) is carried out in a protective gas atmosphere, including but not limited to one or more of nitrogen, helium, neon, and argon, and the protective gas should be of high purity with a purity of ≥99%.

[0032] As a preferred embodiment, step (1) is carried out as follows Figure 1The device shown is used for plating gold-tin alloy, and the device includes a feeding positioning system, a high-purity graphite crucible, a sizing die and a traction positioning system arranged from top to bottom, wherein an induction heating device and a circulating cooling water system are arranged on the outside of the high-purity graphite crucible to achieve heating and temperature control of the melt in the high-purity graphite crucible.

[0033] Specifically, the feeding positioning system and the traction positioning system are used to feed the unreacted single crystal copper rod and to take up the copper rod coated with gold-tin alloy, and provide power for feeding and discharging the copper rod. The high-purity graphite crucible is used to hold the alloy liquid melt and perform plating. The sizing die is used to perform the sizing treatment to ensure that a gold-tin alloy coating layer of a quantitative thickness is obtained.

[0034] As a preferred embodiment, for the copper rod plated with gold-tin alloy, the ratio of the thickness of the gold-tin alloy to the diameter of the single crystal copper rod is 1:80 to 1:10. Those skilled in the art can obtain the copper rod plated with gold-tin alloy in the above ratio by comprehensively adjusting the diameter of the copper rod and the sizing value of the sizing treatment; it is understandable that when the thickness of the outer gold-tin alloy layer is too thin, after the subsequent steps of corrosion and drawing, the gold plating is uneven and cannot play an anti-oxidation effect, resulting in poor bonding performance of the gold-plated copper bonding wire; on the contrary, when the thickness of the outer gold-tin alloy layer is too thick, in the subsequent steps of corrosion and drawing, a large amount of plating will fall off, the plating thickness cannot be effectively increased, and the plating raw materials will be wasted.

[0035] (2) The copper rod plated with the gold-tin alloy is subjected to an acid immersion treatment until no bubbles are generated and a tin-free gold-plated copper rod is obtained.

[0036] As a preferred embodiment, the acid reagent for the acid leaching treatment includes one of dilute hydrochloric acid or dilute sulfuric acid, so as to fully corrode tin without any reaction with copper and gold, and retain the original distribution state of gold on the gold-tin alloy layer.

[0037] As a more preferred embodiment, the acid reagent for the acid leaching treatment is dilute hydrochloric acid with a mass fraction of 5% to 20%.

[0038] As a preferred embodiment, after the acid leaching treatment in step (2), the method further comprises: one or both of alkali washing and water washing; in a more preferred embodiment, the alkali agent of the alkali washing comprises one or more of sodium hydroxide, potassium hydroxide, and ammonia water, and more preferably a sodium hydroxide aqueous solution with a mass fraction of 5% to 15%. The acid residue on the copper rod can be more effectively removed by alkali washing, and the cleaned detinned gold-plated copper rod can be obtained by further water washing.

[0039] (3) The detinned gold-plated copper rod is sequentially subjected to room temperature drawing and online annealing drawing to obtain a gold-plated copper bonding wire.

[0040] As a preferred embodiment, the single deformation rate of the room temperature drawing is 15% to 25%, and the speed of the room temperature drawing is 4 m / s to 30 m / s; in some optional embodiments, the single deformation rate of the room temperature drawing is 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, any one of them or a numerical range composed of any two of them, and the speed of the room temperature drawing is 4, 5, 10, 15, 20, 22, 25, 28, 30 (m / s) or a numerical range composed of any two of them.

[0041] As a preferred embodiment, the temperature of the room temperature drawing is 15°C to 35°C, which is the definition of room temperature in the conventional understanding in the art; in a more preferred embodiment, the temperature of the room temperature drawing is 20°C to 30°C.

[0042] As a preferred embodiment, the copper rod is drawn at room temperature until its diameter is 0.5 mm.

[0043] As a preferred embodiment, the online annealing and drawing comprises the following steps: heating the gold-plated copper wire that has been drawn at room temperature to a certain temperature, controlling the cooling rate to cool it down while drawing and reducing the diameter; in some optional embodiments, the online annealing and drawing can be carried out by a continuous annealing wire drawing machine, which is widely used in the drawing of non-ferrous metals such as copper and aluminum.

[0044] As a preferred embodiment, the temperature of the online annealing and drawing is 350°C to 450°C, including but not limited to any one of 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450 (°C) or a numerical range consisting of any two of them. By limiting the temperature of the online annealing and drawing, high temperature recovery occurs at a specific temperature, which helps to obtain a good annealing and drawing effect.

[0045] As a preferred embodiment, the annealing time of the online annealing and drawing is 1s to 3s; in some more preferred embodiments, the cooling rate of the online annealing and drawing is 100℃ / s to 200℃ / s, and the temperature is reduced to room temperature before the drawing die, and the room temperature refers to 20℃ to 25℃.

[0046] As a preferred embodiment, the online annealing and drawing is carried out in a protective gas atmosphere, including but not limited to one or more of nitrogen, helium, neon, and argon, and the protective gas should be of high purity with a purity of ≥99%.

[0047] As a preferred embodiment, the single deformation rate of the online annealing and drawing is 2% to 10%, and the speed of the online annealing and drawing is 3 m / s to 30 m / s; in some optional embodiments, the single deformation rate of the online annealing and drawing is any one of 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a numerical range composed of any two of them, and the speed of the online annealing and drawing is any one of 3, 5, 10, 15, 20, 22, 25, 28, 30 (m / s), or a numerical range composed of any two of them.

[0048] As a preferred embodiment, the diameter of the gold-plated copper bonding wire is 15 μm to 50 μm, including but not limited to any one of 15, 20, 25, 30, 35, 40, 45, 50 (μm) or a numerical range consisting of any two of them.

[0049] The second aspect of the present invention is to provide a gold-plated copper bonding wire, which is prepared based on the preparation method of the gold-plated copper bonding wire as described in the first aspect.

[0050] The third aspect of the present invention is to provide the use of the gold-plated copper bonding wire as described in the second aspect in packaging; it can be understood that the use includes but is not limited to other processed bonding wire products containing the gold-plated copper bonding wire, packaging processes based on the gold-plated copper bonding wire, electronic products obtained by packaging the gold-plated copper bonding wire, etc. Any product or method related to the packaging field under the premise of involving the gold-plated copper bonding wire can be used as an implementation method in this aspect.

[0051] Example 1

[0052] S1: Weigh pure gold and tin raw materials (raw material purity ≥ 99.999%) in a mass ratio of 80%:20%, put them into a pre-prepared alumina crucible, and then put them into a vacuum induction melting furnace for melting; before melting, evacuate the cavity of the induction melting furnace to 10 -3 Pa, and then backfill with high-purity argon gas to 10 -2 Pa; heat to 400°C, stir evenly after the alloy is completely melted; after smelting, cool with the furnace under high-purity argon gas to obtain the gold-tin master alloy.

[0053] S2: By Figure 1The plating equipment shown is used to plate a gold-tin alloy layer on the surface of a single crystal copper rod; first, the gold-tin master alloy prepared by S1 is put into a high-purity graphite crucible, the crucible furnace body is sealed, and high-purity argon gas is filled in the device to a slightly positive pressure (exceeding 1 atmosphere 100Pa~200Pa), and then induction heating is turned on to 325°C; a single crystal copper rod with a diameter of 4mm is fixed to a feeding and positioning system, and the copper rod is fed into the high-purity graphite crucible at a speed of 0.01m / s, and the plated copper rod is obtained by the traction and positioning system, and after cooling to room temperature, a copper rod with a gold-tin alloy layer on the surface is obtained, with a total diameter of 4.2mm.

[0054] S3: The copper rod obtained in S2 is immersed in 10wt.% hydrochloric acid and reacted until there are no bubbles; then transferred to 10wt.% sodium hydroxide aqueous solution for neutralization for 5 minutes, and then rinsed with deionized water, and dried in a high-purity argon atmosphere at 70°C for use.

[0055] S4: The copper rod obtained in S3 was drawn at a single deformation rate of 20% and a speed of 20 m / s to obtain a gold-plated copper wire with a total diameter of 0.5 mm.

[0056] S5: Drawing is performed at 400° C. in a high-purity argon atmosphere, with an annealing time of 2 seconds, and online annealing and pulling is performed at a single deformation rate of 8% and a speed of 20 m / s to obtain a gold-plated copper bonding wire with a diameter of 30 μm in this embodiment.

[0057] like Figure 2 The figure shows a finished product of the gold-plated copper bonding wire of Example 1; Figure 3 The SEM image of the finished product of the gold-plated copper bonding wire of Example 1 at a scale of 10 μm is shown. Figure 2 , Figure 3 It can be seen that the coating surface is flat and smooth without obvious defects.

[0058] Example 2

[0059] It is basically the same as Example 1, the only difference is: S2, S4 and S5, while S1 and S3 are consistent with the example; specifically:

[0060] S2: By Figure 1 The plating equipment shown is used to plate a gold-tin alloy layer on the surface of a single crystal copper rod; first, the gold-tin master alloy prepared by S1 is put into a high-purity graphite crucible, the crucible furnace body is closed, and high-purity argon gas is filled in the device to a slightly positive pressure (100-200 Pa exceeding 1 atmosphere), and then induction heating is turned on to 325°C; a single crystal copper rod with a diameter of 2 mm is fixed to a feeding and positioning system, and the copper rod is fed into the high-purity graphite crucible at a speed of 0.1 m / s, and the plated copper rod is obtained by the traction and positioning system, and the copper rod with a gold-tin alloy layer on the surface is obtained after cooling to room temperature, and the total diameter is 2.1 mm;

[0061] S4: The copper rod obtained in S3 is drawn at a single deformation rate of 15% and a speed of 25 m / s to obtain a gold-plated copper wire with a total diameter of 0.5 mm;

[0062] S5: Drawing is performed at 400° C. in a high-purity argon atmosphere, with an annealing time of 2 seconds, and online annealing and pulling is performed at a single deformation rate of 4% and a speed of 25 m / s to obtain a gold-plated copper bonding wire with a diameter of 20 μm in this embodiment.

[0063] Example 3

[0064] It is basically the same as Example 1, the only difference is: S2, S4 and S5, while S1 and S3 are consistent with the example; specifically:

[0065] S2: By Figure 1 The plating equipment shown is used to plate a gold-tin alloy layer on the surface of a single crystal copper rod; first, the gold-tin master alloy prepared by S1 is put into a high-purity graphite crucible, the crucible furnace body is closed, and high-purity argon gas is filled in the device to a slightly positive pressure (100-200 Pa exceeding 1 atmosphere), and then induction heating is turned on to 325°C; a single crystal copper rod with a diameter of 8 mm is fixed to a feeding and positioning system, and the copper rod is fed into the high-purity graphite crucible at a speed of 0.05 m / s, and the plated copper rod is obtained by the traction and positioning system, and the copper rod with a gold-tin alloy layer on the surface is obtained after cooling to room temperature, and the total diameter is 8.2 mm;

[0066] S4: The copper rod obtained in S3 is pulled at a single deformation rate of 25% and a speed of 5 m / s to obtain a gold-plated copper wire with a total diameter of 0.5 mm;

[0067] S5: Drawing is performed at 400° C. in a high-purity argon atmosphere, with an annealing time of 2 seconds, and online annealing and pulling is performed at a single deformation rate of 10% and a speed of 5 m / s to obtain a gold-plated copper bonding wire with a diameter of 50 μm in this embodiment.

[0068] Example 4

[0069] It is basically the same as Example 1, except that:

[0070] S3: The copper rod prepared in S2 is immersed in 5wt.% hydrochloric acid to react until no bubbles are formed, and then rinsed with deionized water and dried in a high-purity argon atmosphere at 80°C for later use.

[0071] Example 5

[0072] It is basically the same as Example 1, except that:

[0073] S5: Drawing is performed at 350° C. in a high-purity argon atmosphere, with an annealing time of 1 s, and online annealing and pulling is performed at a single deformation rate of 4% and a speed of 25 m / s to obtain a gold-plated copper bonding wire with a diameter of 20 μm in this embodiment.

[0074] Example 6

[0075] It is basically the same as Example 1, except that:

[0076] S5: Drawing is performed at 450° C. in a high-purity argon atmosphere, the annealing time is 3 s, and online annealing and pulling is performed at a single deformation rate of 4% and a speed of 25 m / s to obtain a gold-plated copper bonding wire with a diameter of 20 μm in this embodiment.

[0077] Comparative Example

[0078] Commercially available gold-plated copper bonding wire, 25 μm in diameter, with a coating thickness of 0.1 μm.

[0079] Test example

[0080] The following performance tests were performed on the bonding wires prepared in the embodiments and comparative examples, and the test results are recorded in Table 1.

[0081] (1) Gold plating uniformity test: Take any 5-axis bonding wire finished product of each embodiment and comparative example, take 200 meters of each axis, respectively, use 1% by mass ferric chloride solution to corrode the bonding wire for 1 minute, then soak it in deionized water and anhydrous alcohol and dry it, and then put it into a laser confocal microscope to observe the surface morphology of the bonding wire. When the color of the bonding wire does not change significantly from that before corrosion, it means that the plating layer is uniform, continuous and dense, and the bonding force between the plating layer and the copper core is good; when block-shaped black areas appear on the surface morphology of the bonding wire, these areas show the color of copper after being corroded by ferric chloride solution, which proves that the sample is severely corroded, indicating that the continuity and uniformity of the plating layer are poor, and the solution can corrode the copper core through the plating layer.

[0082] (2) Antioxidation test: Take 200 meters of each of the five-axis bonding wires of each embodiment and comparative example, store them at 100°C and 80% humidity for 1 hour, soak them in anhydrous alcohol and dry them, and observe the surface morphology of the bonding wires under a laser confocal microscope. When the color of the bonding wires does not change significantly from that before corrosion, it indicates that the coating has good oxidation resistance; when blocky brown areas (i.e., oxidized colors) appear on the surface of the bonding wires, it indicates that the samples are oxidized, indicating that the bonding wires have poor oxidation resistance.

[0083] Table 1

[0084]

[0085]

[0086] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a gold-plated copper bonding wire, characterized in that: The steps include: (1) immersing a single crystal copper rod into a melt of a gold-tin alloy, and then performing a sizing treatment to obtain a copper rod coated with the gold-tin alloy; (2) subjecting the copper rod plated with the gold-tin alloy to an acid immersion treatment until no bubbles are generated and a detinned gold-plated copper rod is obtained; (3) The detinned gold-plated copper rod is sequentially subjected to room temperature drawing and online annealing drawing to obtain a gold-plated copper bonding wire.

2. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The gold-tin alloy includes 19% to 21% tin and 79% to 81% gold by mass.

3. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The temperature of the gold-tin alloy melt is 300° C. to 350° C.

4. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: In the copper rod plated with gold-tin alloy, the ratio of the thickness of the gold-tin alloy to the diameter of the single crystal copper rod is 1:80 to 1:10; Preferably, the diameter of the single crystal copper rod is 1 mm to 8 mm; And / or, the thickness of the gold-tin alloy plated layer is 0.1 mm to 0.5 mm.

5. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The acid reagent for the acid leaching treatment includes one of dilute hydrochloric acid or dilute sulfuric acid, preferably a 5wt.% to 20wt.% hydrochloric acid solution; Preferably, the acid leaching treatment further includes one or both of alkali washing and water washing, and the alkali agent of the alkali washing includes at least one of sodium hydroxide solution, potassium hydroxide solution or ammonia water.

6. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The single deformation rate of the room temperature drawing is 15% to 25%, and the speed of the room temperature drawing is 4m / s to 30m / s; And / or, the copper rod is drawn at room temperature until its diameter is 0.4 mm to 0.6 mm.

7. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The temperature of the online annealing and drawing is 350° C. to 450° C., and the annealing time of the online annealing and drawing is 1 second to 3 seconds.

8. The method for preparing a gold-plated copper bonding wire according to claim 1, characterized in that: The single deformation rate of the online annealing and drawing is 2% to 10%, and the speed of the online annealing and drawing is 3m / s to 30m / s; And / or, the diameter of the gold-plated copper bonding wire is 15 μm to 50 μm.

9. The gold-plated copper bonding wire obtained by the method for preparing a gold-plated copper bonding wire according to any one of claims 1 to 8.

10. Use of the gold-plated copper bonding wire according to claim 9 in packaging.

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