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

Abstract

The invention provides a gold-copper composite bonding wire and a preparation method and application thereof, and relates to the technical field of bonding wires. Specifically, a single-crystal copper rod and a gold tube which are equal in length are firstly configured, and the single-crystal copper rod and the gold tube are of a slotted hole-tooth meshing structure or a nested structure; performing low-temperature treatment on the single-crystal copper rod, and then inserting the single-crystal copper rod into a pipeline of the gold pipe to obtain an interference fit composite blank; and sequentially carrying out vacuum annealing, drawing and on-line annealing and drawing on the composite blank to obtain the gold-copper bonding wire. The prepared gold-copper bonding wire has the chemical stability and the bonding performance of a gold bonding wire and the high hardness and the high conductivity of a copper bonding wire, meanwhile, the preparation process is energy-saving and environment-friendly, the controllability is high, the cost is reduced, the production efficiency and the yield are remarkably improved, and the gold-copper bonding wire has a good application prospect.

Description

Technical Field

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

[0002] As modern electronic devices continue to develop towards miniaturization and high performance, the heat dissipation of bonding wires has gradually become one of the hot topics of research. Bonding wires are tiny wires that connect chips to external pins. They can conduct the heat generated by the chip during operation and play an important role in heat dissipation. When the electronic components in the chip perform high-speed calculations or process signals, Joule heat will be generated. This heat must be dissipated in time, otherwise it will affect the performance and life of the chip. However, the heat dissipation performance of bonding wires faces many challenges. On the one hand, the size of the bonding wire is extremely small, which limits its heat conduction capacity to a certain extent. Its diameter is usually around tens of microns, and the cross-sectional area of ​​heat conduction is limited, making it difficult to conduct heat as efficiently as larger heat dissipation structures. On the other hand, bonding wires may age and break during long-term use. Once a bonding wire fails, its heat dissipation function will be greatly reduced, which will affect the stability of the entire electronic device.

[0003] In order to improve the heat dissipation performance of bonding wires, existing technologies provide a variety of solutions. In terms of materials, the development of bonding wire materials with higher thermal conductivity, such as certain alloy materials, can effectively improve the efficiency of heat conduction. In terms of structural design, the layout of bonding wires is optimized, such as reasonably increasing the number of bonding wires or changing their connection methods, thereby increasing the overall thermal conductivity of the heat dissipation channel. In addition, by improving the bonding process, improving the connection quality between the bonding wire and the chip and pins, and reducing the contact thermal resistance, it is also helpful to improve the heat dissipation effect.

[0004] Gold is a traditional bonding wire material with obvious performance in terms of conductivity, chemical stability, bonding performance, plasticity, ductility and operability. However, on the one hand, gold is a precious metal and its price is relatively high. For mass-produced electronic devices, such as consumer electronics, the high cost of bonding gold wires will increase the manufacturing cost of the products, thereby affecting the market competitiveness of the products. On the other hand, the hardness of gold is relatively low. In some special application scenarios, such as in environments that need to withstand greater mechanical pressure or friction, or in electronic device interface parts that need to be frequently plugged in and out or work in high vibration environments, bonding gold wires will be deformed or worn.

[0005] Therefore, the application share of pure gold bonding wire in the packaging field has been decreasing year by year, and gold-plated bonding wire has become a more cost-effective alternative; gold-plated bonding wire usually uses a copper metal core and a gold-plated surface layer. It can overcome certain heat dissipation problems, mechanical strength and cost issues while retaining the advantages of traditional gold bonding wire, making it have the advantages of both gold and copper metals. However, gold-plated copper bonding wire also faces some new usage problems: copper has a high hardness, which makes gold-plated bonding wires in some delicate electronic packaging applications may cause certain stress to the device, especially under conditions such as multiple bending or thermal cycling, which may cause the bonding wire to break or be damaged, affecting the reliability and service life of electronic equipment.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The first purpose of the present invention is to provide a method for preparing a gold-copper bonding wire, which is used to solve the defects of poor heat dissipation effect, low hardness or high cost of traditional gold bonding wires, and the defects of thin coating of gold-plated copper bonding wires prepared by conventional gold plating processes, as well as the defects of the above two bonding wires that reduce the reliability and service life of electronic devices after bonding packaging.

[0008] The second object of the present invention is to provide a gold-copper bonding wire obtained by the preparation method of the gold-copper bonding wire, which has the chemical stability and bonding performance of the gold bonding wire and the high hardness, strong heat dissipation and high conductivity of the copper bonding wire.

[0009] The third object of the present invention is to provide the application of the gold-copper bonding wire in packaging.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0011] A method for preparing a gold-copper bonding wire comprises the following steps:

[0012] (1) One of the following (a) or (b) is used as the metal raw material:

[0013] (a) a single crystal copper rod having a tooth structure evenly distributed on the curved surface, and a gold tube having a slot structure evenly distributed on the inner curved surface; the single crystal copper rod and the gold tube have the same length, and the slot structure and the tooth structure match;

[0014] (b) a gold tube having at least four tubes equidistantly distributed in the length direction, and single crystal copper rods having the same number as the tubes; and the single crystal copper rods and the gold tubes have the same length;

[0015] (2) subjecting the single crystal copper rod to low temperature treatment and then inserting it into the pipe of the gold tube to obtain a composite blank with interference fit;

[0016] (3) The composite blank is subjected to vacuum annealing, drawing, and online annealing and drawing in sequence to obtain a gold-copper bonding wire.

[0017] A gold-copper bonding wire is prepared based on the preparation method of the gold-copper bonding wire, and the use of the gold-copper bonding wire in packaging.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention provides a method for preparing a gold-copper bonding wire, including two possible raw material preparations; one is to use an even number of slot-tooth structures to increase the heat dissipation area of ​​the outer surface gold, the gold layer near the slot-tooth structure is thicker and softer during bonding, so that the prepared gold-copper bonding wire is not easy to generate stress or break during packaging; the second is to use a gold tube with an even number of tube gaps so that the copper rod is nested and matched with the gold-copper bonding wire, so that during the wire feeding process of bonding, the thicker gold layer of the prepared gold-copper bonding wire is ensured to be in continuous contact with the pad, effectively ensuring the properties of the outer gold layer and the inner copper layer in bonding.

[0020] (2) The gold-copper bonding wire prepared by the present invention has the chemical stability and bonding performance of the gold bonding wire, as well as the high hardness and high conductivity of the copper bonding wire, and the cost is 30% to 40% lower than that of the traditional gold bonding wire; at the same time, the production efficiency of the preparation process of the present invention is improved by 60% to 70% as a whole compared with conventional electroplating or chemical plating, and the yield rate is improved by 10% to 20%.

[0021] (3) The preparation method of the present invention achieves interference fit by inserting a low-temperature copper rod into a gold tube, which is energy-saving, environmentally friendly, and effectively improves production efficiency; at the same time, the length parameters of the two metal raw materials can be designed in the present invention, and the cross-sectional area ratio can be adjusted, which is beneficial to improving the coordination of cold working deformation of gold and copper; further, metallurgical bonding is achieved through vacuum annealing, and intermetallic compounds are formed at the gold-copper interface, which effectively improves the gold-copper bonding strength; further, the online annealing and drawing process is adopted, which can effectively reduce the number of wire breaks under the three-phase compressive stress state, and significantly improve the yield rate and production efficiency of the gold-copper bonding wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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.

[0023] Figure 1 A schematic cross-sectional view of a composite blank according to Example 1 of the present invention is provided;

[0024] Figure 2 A schematic cross-sectional view of a composite blank according to Example 2 of the present invention is provided;

[0025] Figure 3 A schematic cross-sectional view of a composite blank according to Example 3 of the present invention is provided;

[0026] Figure 4 A schematic cross-sectional view of a composite blank according to Example 4 of the present invention is provided;

[0027] Figure 5 A schematic cross-sectional view of a composite blank according to Example 5 of the present invention is provided. DETAILED DESCRIPTION

[0028] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art 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. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "left", "right", "vertical", "horizontal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] A first aspect of the present invention is to provide a method for preparing a gold-copper bonding wire.

[0031] (1) One of the following (a) or (b) is configured as the metal raw material: for the raw material combination (a), a group of mutually interlocking single crystal copper rods and gold tubes are configured through a slot-tooth structure; for the raw material combination (b), a number of thinner single crystal copper rods and gold tubes corresponding to the number of tubes are configured, thereby enabling subsequent assembly and interference fit.

[0032] Firstly, (a) or (b) both satisfy the following preferred method:

[0033] As a preferred embodiment, the copper content of the single crystal copper rod is ≥99.999%; it can be understood that, compared with conventional copper single element materials, by using extremely high purity single crystal copper consisting of only one grain, there is no "grain boundary" generated between the grains, and thus it has extremely high electrical conductivity and thermal conductivity.

[0034] As a preferred embodiment, the surface roughness of the single crystal copper rod and / or the gold tube is Ra0.2 to Ra1.6, including but not limited to any one of Ra0.2, Ra0.3, Ra0.4, Ra0.5, Ra0.6, Ra0.7, Ra0.8, Ra0.9, Ra1.0, Ra1.1, Ra1.2, Ra1.3, Ra1.4, Ra1.5, and Ra1.6, or a numerical range consisting of any two of them; it is worth noting that the surface roughness in this embodiment mainly refers to the curved surface of the single crystal copper rod, and the cross-section of the single crystal copper rod may not be within the above-mentioned limited range.

[0035] As a preferred implementation, the gold content of the gold tube is ≥99.999%.

[0036] (a) A single crystal copper rod with a tooth structure evenly distributed on the curved surface, and a gold tube with a slot structure evenly distributed on the inner curved surface; the single crystal copper rod and the gold tube have the same length, and the slot structure matches the tooth structure.

[0037] As a preferred embodiment, for (a), the diameter of the single crystal copper rod is 2 mm to 10 mm, including but not limited to any one of 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 8.5, 9, 9.5, 10 (mm) or a numerical range consisting of any two of them; it is worth noting that the diameter of the single crystal copper rod described here is not a parameter that measures the tooth structure.

[0038] As a preferred embodiment, the thickness of the tooth structure is 10% to 30% of the diameter of the single crystal copper rod. It is worth noting that the cross-section of the tooth structure is preferably rectangular, the tooth structure is a tooth protruding from the surface of the single crystal copper rod, and the thickness of the tooth structure can be understood as the distance between the long side of the rectangle and the arc surface of the single crystal copper rod; it is also worth noting that the height of the groove of the slot structure of the gold tube can be obtained by the thickness of the tooth structure, because the tooth structure and the groove structure should match each other, so the specifications should be consistent.

[0039] As a preferred embodiment, the number of the slot structures and the tooth structures is an even number; as a more preferred embodiment, the number of the slot structures and the tooth structures is 6 to 18, including but not limited to one of 6, 8, 10, 12, 14, 16, and 18.

[0040] It should also be noted that, since the slot structure is defined as "uniformly distributed" in the present invention, the distance between adjacent slot structures is the same, and similarly, the distance between adjacent tooth structures is also the same.

[0041] As a preferred embodiment, for (a), the inner diameter of the gold tube is 8 mm to 20 mm, including but not limited to any one of 8, 8.5, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 18.5, 19, 19.5, 20 (mm) or a numerical range formed by any two of them; it is worth noting that the inner diameter of the gold tube described here is a parameter that does not measure the slot structure, and can also be understood as the maximum inner diameter value of the gold tube when it does not include the teeth that constitute the slot structure.

[0042] As a preferred implementation, in (a), the outer diameter of the gold tube is 1.05 to 2.00 times the diameter of the single crystal copper rod.

[0043] As a preferred embodiment, the difference between the sum of the diameter of the single crystal copper rod and the thickness of the tooth structure and the inner diameter of the gold tube is 0.005mm~0.01mm, that is, the total length of the single crystal copper rod and the tooth structure in the rod cross-section direction is still 0.005mm~0.01mm larger than the inner diameter of the gold tube without teeth (slot structure); in some optional embodiments, the above difference includes but is not limited to any one of 0.005, 0.006, 0.007, 0.008, 0.009, 0.01 (mm) or a numerical range composed of any two of them.

[0044] (b) A gold tube having at least four tubes equidistantly distributed in the length direction, and single crystal copper rods having the same number as the tubes; and the single crystal copper rods and the gold tubes have the same length.

[0045] It should be noted that there are several pipes distributed equidistantly inside the gold tube, and the pipes are in the length direction of the gold tube; it can also be understood that there are several concentric holes in the length direction of the gold tube for assembling the single crystal copper rod. For the equidistant distribution, it can be understood that the distance between any two adjacent pipes is the same, whether measured by the center of the pipe or the inner wall of the pipe.

[0046] As a preferred embodiment, for (b), the diameter of each of the single crystal copper rods is independently selected from 2 mm to 10 mm, including but not limited to any one of 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 8.5, 9, 9.5, 10 (mm) or a numerical range consisting of any two of them; in some more preferred embodiments, the diameter of each of the single crystal copper rods is the same, which also means that the inner diameters of the tubes in the gold tube are the same.

[0047] As a preferred implementation manner, the outer diameter (total diameter) of the gold tube is 3 to 8 times the diameter of the single crystal copper rod.

[0048] As a preferred embodiment, for (b), the inner diameter of each of the pipes is independently selected from 8 mm to 20 mm, including but not limited to any one of 8, 8.5, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 18.5, 19, 19.5, 20 (mm) or a numerical range consisting of any two of them.

[0049] As a preferred implementation, the number of the pipelines is 4 to 16 and the number of the pipelines is an even number, including but not limited to one of 4, 6, 8, 10, 12, 14, and 16.

[0050] As a preferred embodiment, the difference between the diameter of the single crystal copper rod and the inner diameter of the pipe is 0.005mm-0.01mm, that is, the diameter of the single crystal copper rod is slightly larger than the inner diameter of the pipe; in some optional embodiments, the above difference includes but is not limited to any one of 0.005, 0.006, 0.007, 0.008, 0.009, 0.01 (mm) or a numerical range consisting of any two of them. That is, whether for (a) or (b), it is satisfied that the fitting clearance between the single crystal copper rod and the gold pipe is 0.005mm-0.01mm.

[0051] (2) The single crystal copper rod is subjected to low temperature treatment and then inserted into the pipe of the gold tube to obtain a composite blank with interference fit.

[0052] In this step, the copper rod is first subjected to low temperature treatment to be cold compressed and its volume is reduced, thereby enabling the copper rod with a slightly higher diameter to be inserted into the pipe of the gold tube; after the insertion, the composite blank is heated up with the room temperature, and the volume of the copper rod expands to its original volume, and the elasticity of the metal material is utilized to achieve the expansion and deformation of the gold tube and to be tightly nested on the copper rod, thereby generating a clamping force on the copper rod and achieving the connection between the two.

[0053] As a preferred embodiment, the temperature of the cryogenic treatment is -180°C to -220°C, and the time of the cryogenic treatment is 10 min to 20 min. As a more preferred embodiment, the cryogenic treatment is carried out using liquid nitrogen, the temperature of the liquid nitrogen is -195°C to -210°C, and the time of the cryogenic treatment includes but is not limited to any one of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 (min) or a numerical interval consisting of any two of them.

[0054] As a preferred embodiment, after the low-temperature treatment of the single crystal copper rod, it is necessary to insert it into the gold tube as soon as possible while it is cold; as a more preferred embodiment, the single crystal copper rod is subjected to low-temperature treatment, and the low-temperature single crystal copper rod is inserted into the pipe of the gold tube within 10 seconds.

[0055] (3) The composite blank is subjected to vacuum annealing, drawing, and online annealing and drawing in sequence to obtain a gold-copper bonding wire.

[0056] In this step, vacuum annealing is first used to achieve metallurgical bonding between gold and copper, and then the first diameter reduction is performed by drawing, and then the second diameter reduction is performed by online annealing and drawing, thereby achieving efficient, precise, and energy-saving processing of the composite billet to the wire, and obtaining high-quality gold-copper bonding wires.

[0057] As a preferred implementation manner, the vacuum degree of the vacuum annealing is 0.05Pa-0.1Pa.

[0058] As a preferred embodiment, the vacuum annealing temperature is 400°C to 450°C, and the vacuum annealing time is 0.5h to 1h; as a more preferred embodiment, the vacuum annealing temperature includes but is not limited to any one of 400, 405, 410, 415, 420, 425, 430, 435, 440, 445, 450 (°C) or a numerical range consisting of any two of them.

[0059] As a preferred embodiment, after the drawing, a wire with a diameter of 0.5 mm is obtained.

[0060] As a preferred embodiment, the single deformation rate of the drawing is 15% to 25%, and the drawing speed is 4 m / s to 30 m / s.

[0061] As a preferred embodiment, the online annealing and drawing is carried out in a protective gas environment, including but not limited to one or more of nitrogen, helium, neon, and argon.

[0062] As a preferred embodiment, the annealing temperature of the online annealing and drawing is 350°C to 450°C, and the annealing time of the online annealing and drawing is 1s to 3s; as a more preferred embodiment, the temperature of the vacuum annealing includes but is 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.

[0063] As a preferred implementation manner, the single deformation rate of the online annealing and drawing is 2% to 10%, and the drawing speed is 3 m / s to 30 m / s.

[0064] As a preferred implementation, the diameter of the gold-copper bonding wire is 15 μm to 50 μm.

[0065] The second aspect of the present invention is to provide a gold-copper bonding wire prepared by the method for preparing a gold-copper bonding wire as described in the first aspect.

[0066] The third aspect of the present invention is to provide the use of the gold-copper bonding wire prepared by the preparation method of the gold-copper bonding wire as described in the first aspect in packaging, including but not limited to other bonding wire products processed on the basis of the gold-copper bonding wire, the method of using the gold-copper bonding wire in electronic product packaging, and electronic products packaged based on the gold-copper bonding wire. It can be understood that when the gold-copper bonding wire is involved, any product or method in the field of packaging or bonding wire can be used as an embodiment of the present invention.

[0067] Example 1

[0068] (1) Raw material preparation:

[0069] 1.1) A single crystal copper rod (copper content ≥ 99.999%) with a diameter of 20 mm and a length of 1 m, with 6 teeth evenly arranged on the copper rod, a tooth height of 3 mm, and a tooth angle of 15°;

[0070] 1.2) A gold tube with an outer diameter of 30 mm and a length of 1 m (gold content ≥ 99.999%), with 6 tooth grooves on the gold tube, the tooth grooves and teeth matching each other; the matching clearance between the single crystal copper rod and the gold tube is 0.01 mm.

[0071] (2) Assembly of gold tube and single crystal copper rod:

[0072] The single crystal copper rod was placed in liquid nitrogen (-196°C) for 15 minutes, then taken out and immediately (within 2 seconds) inserted into the slot of the gold tube. When it returned to room temperature, the copper rod expanded and the tube and the rod formed an interference fit to obtain a composite blank with a diameter of 30 mm. Figure 1 A schematic cross-sectional view of a composite blank is provided.

[0073] (3) Vacuum compound:

[0074] Perform vacuum annealing on the composite blank and set the vacuum degree to 1*10 -1 Pa, and then heated to 425°C and annealed for 0.75h.

[0075] (4) Drawing:

[0076] The composite blank was drawn to a diameter of 0.5 mm at a single deformation rate of 20%, and the drawing speed was maintained at 20 m / s.

[0077] (5) Online annealing and drawing:

[0078] Annealing was carried out at 400°C in a high-purity argon atmosphere for 2 seconds, and pulling was performed simultaneously during annealing. The single deformation rate was 6% and the pulling speed was maintained at 20m / s, obtaining a gold-copper bonding wire with a diameter of 30μm.

[0079] Example 2

[0080] The embodiment is basically the same as the embodiment 1, except that: (1) there are 12 teeth evenly arranged on the copper rod and 12 tooth grooves on the gold tube; Figure 2 The figure shows a schematic cross-sectional view of the composite blank obtained in step (2) of this embodiment.

[0081] Example 3

[0082] The embodiment is basically the same as the embodiment 1, except that: (1) there are 18 teeth evenly arranged on the copper rod and 18 tooth grooves on the gold tube; Figure 3 The figure shows a schematic cross-sectional view of the composite blank obtained in step (2) of this embodiment.

[0083] Example 4

[0084] (1) Raw material preparation:

[0085] 1.1) 4 single crystal copper rods (copper content ≥ 99.999%) with a diameter of 5 mm and a length of 1 m;

[0086] 1.2) A gold tube with an outer diameter of 20 mm and a length of 1 m (gold content ≥ 99.999%). The gold tube has 4 pipes, and the pitch circle diameter of the pipes is 10 mm; the fitting clearance between the copper rod and the gold tube is 0.01 mm.

[0087] (2) Assembly of gold tube and single crystal copper rod:

[0088] The single crystal copper rod was placed in liquid nitrogen (-196°C) for 15 minutes, then taken out and immediately (within 2 seconds) inserted into the pipeline of the gold tube. When it returned to room temperature, the copper rod expanded and the tube and the rod formed an interference fit to obtain a composite blank with a diameter of 20 mm. Figure 4 A schematic cross-sectional view of a composite blank is provided.

[0089] (3) Vacuum compound:

[0090] Perform vacuum annealing on the composite blank and set the vacuum degree to 1*10 -1 Pa, and then heated to 425°C and annealed for 0.75h.

[0091] (4) Drawing:

[0092] The composite blank was drawn to a diameter of 0.5 mm at a single deformation rate of 20%, and the drawing speed was maintained at 20 m / s.

[0093] (5) Online annealing and drawing:

[0094] Annealing was carried out at 400°C in a high-purity argon atmosphere for 2 seconds, and pulling was performed simultaneously during annealing. The single deformation rate was 6% and the pulling speed was maintained at 20m / s, obtaining a gold-copper bonding wire with a diameter of 30μm.

[0095] Example 5

[0096] The method is basically the same as Example 1, except that: (1) the raw material preparation:

[0097] 1.1) 6 single crystal copper rods (copper content ≥ 99.999%) with a diameter of 4 mm and a length of 1 m;

[0098] 1.2) A gold tube with an outer diameter of 20 mm and a length of 1 m (gold content ≥ 99.999%). The gold tube has 6 pipelines with a pitch circle diameter of 12 mm. The assembly clearance between the copper rod and the gold tube is 0.01 mm.

[0099] like Figure 5 The figure shows a schematic cross-sectional view of the composite blank obtained in step (2) of this embodiment.

[0100] Example 6

[0101] It is basically the same as Example 1, except that:

[0102] (4) Drawing: The composite blank is drawn to a diameter of 0.5 mm at a single deformation rate of 15%, and the drawing speed is maintained at 30 m / s;

[0103] (5) Online annealing and drawing: With a single deformation rate of 2% and a drawing speed of 30 m / s, a gold-copper bonding wire with a diameter of 30 μm was obtained.

[0104] Example 7

[0105] It is basically the same as Example 1, except that:

[0106] (4) Drawing: The composite blank is drawn to a diameter of 0.5 mm at a single deformation rate of 25%, and the drawing speed is maintained at 10 m / s;

[0107] (5) Online annealing and drawing: With a single deformation rate of 10% and a drawing speed of 5 m / s, a gold-copper bonding wire with a diameter of 30 μm was obtained.

[0108] Example 8

[0109] It is basically the same as Example 4, except that:

[0110] (4) Drawing: The composite blank is drawn to a diameter of 0.5 mm at a single deformation rate of 15%, and the drawing speed is maintained at 30 m / s;

[0111] (5) Online annealing and drawing: With a single deformation rate of 2% and a drawing speed of 30 m / s, a gold-copper bonding wire with a diameter of 30 μm was obtained.

[0112] Example 9

[0113] It is basically the same as Example 4, except that:

[0114] (4) Drawing: The composite blank is drawn to a diameter of 0.5 mm at a single deformation rate of 25%, and the drawing speed is maintained at 10 m / s;

[0115] (5) Online annealing and drawing: With a single deformation rate of 10% and a drawing speed of 5 m / s, a gold-copper bonding wire with a diameter of 30 μm was obtained.

[0116] Comparative Example 1: Commercially available pure gold bonding wire with a diameter of 25 μm.

[0117] Comparative Example 2: Commercially available pure copper bonding wire with a diameter of 25 μm.

[0118] Test Example 2: Testing the performance of the gold-copper bonding wires prepared in the above embodiments and comparative examples; the testing method is as follows:

[0119] S1: Conductivity: The electrical performance test uses a double-arm bridge, the sample length is 1m, and 10 samples are randomly selected from each axis of wire. The average value is taken and recorded in Table 1; for the resistivity results, the larger the resistivity, the poorer the conductivity, and the smaller the resistivity, the better the conductivity.

[0120] S2: Bonding performance: The bonding performance of the bonding wire can be effectively measured by the size of the wire bonding force; the tested bonding wire is wire-bonded to the solder joint of the chip, and after bonding, the bonding wire tension and bonding wire push ball measurements are performed to measure the size of the bonding force. During the bonding wire tension process, the hook hooks the top of the wire arc, at 1 / 5 of the straight-line distance between the first solder joint and the second solder joint. The bonding wire push ball test refers to the shear test of the solder ball, which is used to measure the bonding strength between the first solder joint and the pad.

[0121] For bonding performance, each embodiment and comparative example independently conducted 100 experiments, and averaged values ​​were taken and recorded to obtain the bonding wire pulling force and bonding wire solder ball pushing force shown in Table 1.

[0122] Table 1

[0123] <![CDATA[Resistivity (Ω*mm 2 / m)]]> Bond wire tension (g) Bond wire ball thrust (g) Example 1 0.0207 13.5 32.2 Example 2 0.0206 13.7 31.7 Example 3 0.0204 12.9 30.5 Example 4 0.0199 12.7 31.7 Example 5 0.0197 13.1 32.4 Example 6 0.0193 13.3 33.1 Example 7 0.0201 13.7 31.2 Example 8 0.0207 13.5 32.7 Example 9 0.0203 13.4 31.5 Comparative Example 1 0.0234 9.2 28.7 Comparative Example 2 0.0175 10.4 25.1

[0124] It can be seen from Table 1 that the gold-copper composite bonding wire prepared based on the present invention can have better performance in bonding performance than the pure copper bonding wire; it can have better performance in electrical conductivity than the pure gold bonding wire; in other words, the gold-copper composite bonding wire of the present invention combines the excellent performance of pure gold and pure copper bonding wires, and has good cost-effectiveness.

[0125] 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-copper bonding wire, characterized in that: The steps include: (1) One of the following (a) or (b) is used as the metal raw material: (a) a single crystal copper rod having a tooth structure evenly distributed on the curved surface, and a gold tube having a slot structure evenly distributed on the inner curved surface; the single crystal copper rod and the gold tube have the same length, and the slot structure and the tooth structure match; (b) a gold tube having at least four tubes equidistantly distributed in the length direction, and single crystal copper rods having the same number as the tubes; and the single crystal copper rods and the gold tubes have the same length; (2) subjecting the single crystal copper rod to low temperature treatment and then inserting it into the pipe of the gold tube to obtain a composite blank with interference fit; (3) The composite blank is subjected to vacuum annealing, drawing, and online annealing and drawing in sequence to obtain a gold-copper bonding wire.

2. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: For metal raw materials (a): The diameter of the single crystal copper rod is 2 mm to 10 mm; The thickness of the tooth structure is 10% to 30% of the diameter of the single crystal copper rod; The inner diameter of the gold tube is 8 mm to 20 mm; The outer diameter of the gold tube is 1.05 to 2.00 times the diameter of the single crystal copper rod.

3. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The number of the slot structures and the number of the tooth structures is an even number, and the number of the slot structures and the number of the tooth structures is 6-18.

4. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: For metal raw materials (b): The diameter of each of the single crystal copper rods is independently selected from 2 mm to 10 mm; The inner diameter of each of the pipes is independently selected from 8 mm to 20 mm; The outer diameter of the gold tube is 3 to 8 times the diameter of the single crystal copper rod.

5. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The number of the pipelines is an even number and the number of the pipelines is 4-16.

6. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The matching clearance between the single crystal copper rod and the gold tube is 0.005 mm to 0.01 mm.

7. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The temperature of the low temperature treatment is -180°C to -220°C, and the time of the low temperature treatment is 10min to 20min.

8. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The preparation method further comprises at least one of the following features (I) to (IV): (I) the temperature of the vacuum annealing is 400°C to 450°C, and the time of the vacuum annealing is 0.5h to 1h; (II) the single deformation rate of the drawing is 15% to 25%, and the drawing speed is 4 m / s to 30 m / s; (III) the annealing temperature of the online annealing and drawing is 350°C to 450°C, and the annealing time of the online annealing and drawing is 1s to 3s; (IV) The single deformation rate of the online annealing drawing is 2% to 10%, and the drawing speed is 3 m / s to 30 m / s.

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

10. Use of the gold-copper bonding wire prepared by the method for preparing the gold-copper bonding wire according to any one of claims 1 to 8 in packaging.

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