Gold-copper bonding wire and preparation method and application thereof

Abstract

The invention provides a gold-copper bonding wire and a preparation method and application thereof, and relates to the technical field of bonding wires. Specifically, firstly, metal raw materials including a copper rod and a gold pipe and a gold rod, a copper pipe and a gold pipe are prepared; assembling the metal raw materials, and performing electron beam welding on the dissimilar metal contact line on the assembled section to obtain a 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 method can effectively overcome the defects that a traditional gold bonding wire is high in cost and poor in high-temperature performance, overcomes the defects that production efficiency is low, production cost is high, pollution is serious and the like when gold plating is conducted through traditional electroplating or chemical plating, has the remarkable advantages of being high in designability, capable of saving energy, environmentally friendly, low in cost, high in production efficiency, high in yield and the like, and has wide application prospects. Good application prospects are realized.

Description

Technical Field

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

[0002] Gold bonding wire is mainly used in the field of semiconductor packaging to connect the internal circuit of the chip with the external pins. The advantages of gold as bonding wire are: good conductivity (ensuring stable transmission of current and reducing signal transmission loss), high reliability (good oxidation resistance and corrosion resistance, able to maintain stable performance in various environments, reducing the risk of packaging failure), easy welding (the welding process of chips and pins is relatively mature, and the welding quality is easy to guarantee), etc.

[0003] However, gold bonding wires also have some disadvantages: high cost and possible softening under certain conditions. For example, high temperature is one of the main factors that cause gold bonding wires to soften; when the temperature rises to a certain level, the crystal structure of gold will change, causing the hardness and strength of the bonding wire to decrease, thus showing a softening characteristic; for example, high-temperature welding or heat treatment during the semiconductor packaging process may cause the gold bonding wire to soften. In addition, the action of chemical substances may also cause the softening of gold bonding wires. If the gold bonding wire softens, it may affect the performance and reliability of semiconductor devices, such as causing poor lead connection, unstable electrical performance and other problems. In practical applications, appropriate measures need to be taken to avoid or reduce the softening of gold bonding wires, such as controlling the temperature and selecting appropriate packaging materials.

[0004] In order to improve the high-temperature performance of bonding wires, researchers are exploring a variety of approaches. In terms of materials, by developing bonding wire materials with higher thermal conductivity, the efficiency of heat conduction can be effectively improved, such as gold-plated copper bonding wires. The preparation process of gold-plated copper bonding wires requires the use of electroplating or chemical plating methods to uniformly plate a layer of gold with a suitable thickness on the surface of the copper bonding wire. However, electroplating and chemical plating cause serious environmental pollution, and the investment in equipment and plant buildings is also relatively large, and the production efficiency is low; at the same time, in the entire manufacturing process, each step must undergo strict quality inspections, including inspections of the diameter accuracy of the wire, the thickness and uniformity of the gold layer, and the process steps are cumbersome.

[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-copper bonding wire, which is used to solve the defects of traditional gold bonding wires, such as high cost and poor high-temperature performance, which affect the reliability and service life of electronic equipment, and to solve the defects of low production efficiency, high production cost, and serious pollution caused by gold plating by electroplating or chemical plating in the preparation process of gold-plated copper bonding wires.

[0007] 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 advantages of good heat dissipation performance, strong conductivity, good chemical stability and high bonding performance.

[0008] The third object of the present invention is to provide the application of the gold-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-copper bonding wire comprises the following steps:

[0011] (1) One of the following (a) or (b) is used as the metal raw material:

[0012] (a) a single crystal copper rod with a diameter of 8 mm to 20 mm and a gold tube with an inner diameter of 8 mm to 20 mm, wherein the single crystal copper rod and the gold tube have the same length;

[0013] (b) a gold rod with a diameter of 2 mm to 10 mm, a single crystal copper tube with an inner diameter of 2 mm to 10 mm, and a gold tube with an inner diameter of 4 mm to 15 mm, wherein the gold rod, the single crystal copper tube, and the gold tube have the same length;

[0014] (2) assembling the metal raw materials, and then electron beam welding the dissimilar metal contact lines on the assembled cross section to obtain a composite blank;

[0015] (3) The composite blank is subjected to vacuum annealing, drawing, and online annealing and drawing in sequence to obtain a gold-copper bonding wire.

[0016] 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.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention provides a low-cost gold-copper composite bonding wire with good high-temperature performance and a preparation method thereof. By adopting the gap matching of a single metal rod and a tube combined with vacuum electron beam welding, a rod-tube or rod-tube-tube assembly connection is achieved, which has the advantages of good metallurgical quality at the welding point, narrow weld, large depth-to-width ratio, and good joint performance; further, vacuum annealing is used to soften the gold, and the tiny gap between the gold and copper is bonded under the action of vacuum to form an intermetallic interface compound to achieve metallurgical bonding, thereby obtaining a dense coating layer with a high-quality bonding surface that is not easy to fall off; further, online annealing and drawing can achieve diameter reduction under a three-phase compressive stress state, so that the bonding strength between the coating layer and the blank rod is increased, while the number of wire breaks is reduced, further improving the yield rate and production efficiency of the gold-plated bonding wire.

[0019] (2) In the preparation process of the present invention, the inner and outer diameters and thicknesses of the metal raw materials of each rod and tube can be flexibly adjusted, so that the thickness of the gold-plated layer is uniform and controllable, and the cross-sectional area coating ratio is adjustable, which is beneficial to improving the coordination of cold working deformation of gold and copper; at the same time, the preparation process of the present invention has the advantages of energy saving, environmental protection, and high production efficiency. Compared with the process of conventional electroplating or chemical plating to produce gold-plated bonding wires, the overall production efficiency of the present invention can be improved by 60% to 70%, the production cost can be reduced by 30% to 40%, and the yield rate can be increased by 10% to 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 A surface SEM image of Example 1 of the present invention after being drawn to 20 μm is provided. DETAILED DESCRIPTION

[0022] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated 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, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0023] 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.

[0024] A first aspect of the present invention is to provide a method for preparing a gold-copper bonding wire.

[0025] (1) One of the following (a) or (b) is configured as the metal raw material: (a) a single crystal copper rod with a diameter of 8 mm to 20 mm and a gold tube with an inner diameter of 8 mm to 20 mm, and the single crystal copper rod and the gold tube are of the same length; (b) a gold rod with a diameter of 2 mm to 10 mm, a single crystal copper tube with an inner diameter of 2 mm to 10 mm, and a gold tube with an inner diameter of 4 mm to 15 mm, and the gold rod, the single crystal copper tube and the gold tube are of the same length.

[0026] It should be noted that when process (b) is used, the hardness of the bonding wire is increased by using a copper tube layer inside gold, and the softening resistance temperature is improved; the conductivity of copper is slightly better than that of gold, the heat generated by resistance is small, and the heat generated in the bonding wire of the bonding component is small; and the thermal conductivity of copper is better than that of gold, and the heat dissipation is better than that of pure gold bonding wire. It can be seen that (b) can effectively enhance the overall heat dissipation effect of the bonding wire compared to pure gold bonding wire, while reducing the high-temperature softening phenomenon of the bonding wire.

[0027] As a preferred embodiment, for (a) and (b), the copper content in the single crystal copper rod and the single crystal copper tube 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.

[0028] As a preferred embodiment, for (a) and (b), the gold content of the gold tube and the gold rod is ≥ 99.999%.

[0029] As a preferred embodiment, for (a), the surface roughness of the single crystal copper rod and / or the gold tube is Ra0.2 to Ra3.2, including but not limited to any one of Ra0.2, Ra0.4, Ra0.5, Ra0.6, Ra0.8, Ra1.0, Ra1.2, Ra1.4, Ra1.6, Ra1.8, Ra2.0, Ra2.2, Ra2.4, Ra2.6, Ra2.8, Ra3.0, and Ra3.2, or a numerical range consisting of any two of them.

[0030] As a preferred embodiment, for (b), the surface roughness of the gold rod, the single crystal copper tube and the gold tube are independently selected from 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, Ra1.6 or a numerical range consisting of any two of them.

[0031] It is worth noting that the surface roughness in the present invention mainly refers to the roughness on the curved surface, and the cross section of each metal raw material may not be within the above-defined range.

[0032] As a preferred embodiment, for (a) and (b), the length of each metal raw material (including the single crystal copper rod, the gold tube, the gold rod and the single crystal copper tube) is 500 mm to 1000 mm, including but not limited to any one of 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 (mm) or a numerical range consisting of any two of them. However, it is worth noting that the length of the metal raw materials included in either (a) or (b) should be the same.

[0033] As a preferred embodiment, for (a), the diameter of the single crystal copper rod or the inner diameter of the gold tube includes but is not limited to any one of 8, 9, 10, 11, 12, 14, 15, 16, 18, 19, 20 (mm) or a numerical range consisting of any two of them.

[0034] As a preferred implementation, for (a), the wall thickness of the gold tube is 2 mm to 3 mm, that is, the total diameter of the gold tube is 12 mm to 26 mm.

[0035] It is worth noting that for (a), since the subsequent steps involve assembling the rod into the pipe of the tube, the inner diameter of the gold tube must be greater than or equal to the diameter of the copper rod; even if the two have the same parameter value range, there is no situation where the inner diameter of the gold tube is smaller than the diameter of the copper rod.

[0036] As a preferred implementation, for (a), there is a fitting clearance between the copper rod and the gold tube, that is, the difference between the inner diameter of the gold tube and the diameter of the copper rod is 0.01 mm to 0.05 mm.

[0037] As a preferred embodiment, for (b), the diameter of the gold rod or the inner diameter of the single crystal copper tube includes but is not limited to any one of 2, 3, 4, 5, 6, 7, 8, 9, 10 (mm) or a numerical range formed by any two of them; the inner diameter of the gold tube includes but is not limited to any one of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 (mm) or a numerical range formed by any two of them.

[0038] As a preferred embodiment, for (b), the wall thicknesses of the single crystal copper tube and the gold tube are independently selected from 2 mm to 3 mm, that is, the total diameter of the single crystal copper tube is 6 mm to 16 mm, and the total diameter of the gold tube is 8 mm to 21 mm.

[0039] It is worth noting that for (b), since the subsequent steps involve assembling the rod into the two-layer pipe, the inner diameter of the single crystal copper tube must be greater than or equal to the diameter of the gold rod; even if the two have the same parameter value range, there is no case where the inner diameter of the single crystal copper tube is smaller than the diameter of the gold rod. Similarly, the inner diameter of the gold tube must be greater than or equal to the outer diameter (total diameter) of the single crystal copper tube. The two have a part of the same value range, and there is no case where the outer diameter of the single crystal copper tube is greater than the inner diameter of the gold tube.

[0040] As a preferred embodiment, for (b), there are fitting gaps between the gold rod, the single crystal copper tube and the gold tube, that is, the difference between the inner diameter of the single crystal copper tube and the diameter of the gold rod is 0.01mm~0.05mm, and the difference between the inner diameter of the gold tube and the outer diameter of the single crystal copper tube is 0.01mm~0.05mm.

[0041] (2) The metal raw materials are assembled, and then the dissimilar metal contact lines on the assembled cross section are electron beam welded to obtain a composite blank.

[0042] For (a), the assembly includes: inserting the single crystal copper rod into the pipe of the gold tube; for (b), the assembly includes: inserting the gold rod into the pipe of the single crystal copper tube, and then merging the two and inserting them into the pipe of the gold tube.

[0043] As a preferred embodiment, for (b), after the assembly is completed, all the dissimilar metal contact lines on the assembled cross section are subjected to electron beam welding to obtain the composite blank.

[0044] As a preferred implementation, the assembled raw materials are fixed by a clamp to avoid obvious gaps or uneven distribution of gaps in the cross section due to fitting clearance.

[0045] As a preferred embodiment, the electron beam welding is performed under vacuum conditions; as a more preferred embodiment, the vacuum degree of the electron beam welding is 10 -1 Pa~6*10 -3 Pa.

[0046] As a preferred implementation manner, the welding current of the electron beam welding is 5 mA to 20 mA, and the welding speed is 50 mm / min to 100 mm / min.

[0047] (3) The composite blank is subjected to vacuum annealing, drawing, and online annealing and drawing in sequence to obtain a gold-copper bonding wire. In this step, the metallurgical bonding between gold and copper is first achieved by vacuum annealing, 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, accurate, and energy-saving processing of the composite blank to the wire, and obtaining high-quality gold-copper bonding wire.

[0048] As a preferred implementation manner, the vacuum degree of the vacuum annealing is 0.05Pa-0.1Pa.

[0049] 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.

[0050] As a preferred embodiment, after the drawing, a wire with a diameter of 0.4 mm to 0.6 mm is obtained.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] As a preferred implementation, 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.

[0055] As a preferred implementation, the diameter of the gold-copper bonding wire is 15 μm to 50 μm.

[0056] 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.

[0057] 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.

[0058] Example 1

[0059] (1) Raw material preparation:

[0060] 1.1) Single crystal copper rod with a diameter of 10 mm and a length of 800 mm, with a copper content of ≥ 99.999% and a surface roughness of Ra2.0;

[0061] 1.2) Gold tube with an outer diameter of 15.05 mm, an inner diameter of 10.05 mm, a length of 800 mm (gold content ≥ 99.999%), and a surface roughness of Ra2.4.

[0062] (2) Contact wire welding:

[0063] First, completely insert the assembled copper rod into the pipeline of the gold tube, put it into the electron beam welding machine and fix it with a clamp, and evacuate it to 5*10 -3 Pa, electron beam welding of the contact lines of the cross sections on both sides is performed, the welding current is 25 mA, and the welding speed is 80 mm / min; after the weldment is completely cooled, it is taken out from the vacuum chamber to obtain a composite blank.

[0064] (3) Vacuum annealing:

[0065] 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.

[0066] (4) Drawing:

[0067] 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.

[0068] (5) Online annealing and drawing:

[0069] 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.

[0070] Example 2

[0071] The method is basically the same as Example 1, except that: (1) the raw material preparation:

[0072] 1.1) Single crystal copper rod with a diameter of 18 mm and a length of 800 mm, with a copper content of ≥ 99.999% and a surface roughness of Ra2.0;

[0073] 1.2) Gold tube with an outer diameter of 24.03 mm, an inner diameter of 18.03 mm, a length of 800 mm (gold content ≥ 99.999%), and a surface roughness of Ra2.4.

[0074] Example 3

[0075] (1) Raw material preparation:

[0076] 1.1) Gold rod with a diameter of 5 mm and a length of 800 mm, with a gold content of ≥99.999% and a surface roughness of Ra0.8;

[0077] 1.2) Single crystal copper tube (copper content ≥ 99.999%) with an outer diameter of 9.02mm, an inner diameter of 5.02mm, and a length of 800mm, and a surface roughness of Ra0.8;

[0078] 1.3) Gold tube (gold content ≥ 99.999%) with an outer diameter of 13.04 mm, an inner diameter of 9.04 mm, and a length of 800 mm, and a surface roughness of Ra0.8.

[0079] (2) Contact wire welding:

[0080] First, completely insert the gold rod into the pipe of the single crystal copper tube, and then insert both into the pipe of the gold tube; put it into the electron beam welding machine and fix it with a clamp, and evacuate it to 5*10-3 Pa, electron beam welding of the contact lines of the cross sections on both sides is performed, the welding current is 25 mA, and the welding speed is 80 mm / min; after the weldment is completely cooled, it is taken out from the vacuum chamber to obtain a composite blank.

[0081] (3) Vacuum annealing:

[0082] 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.

[0083] (4) Drawing:

[0084] 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.

[0085] (5) Online annealing and drawing:

[0086] Annealing was performed 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 20 m / s, obtaining a gold-copper bonding wire with a diameter of 30 μm.

[0087] Example 4

[0088] The method is basically the same as Example 1, except that: (1) the raw material preparation:

[0089] 1.1) Gold rod with a diameter of 2mm and a length of 800mm, with a gold content of ≥99.999% and a surface roughness of Ra0.8;

[0090] 1.2) Single crystal copper tube (copper content ≥ 99.999%) with an outer diameter of 9.02mm, an inner diameter of 2.02mm, and a length of 800mm, and a surface roughness of Ra0.8;

[0091] 1.3) Gold tube with an outer diameter of 15.04 mm, an inner diameter of 9.04 mm, a length of 800 mm (gold content ≥ 99.999%), and a surface roughness of Ra0.8.

[0092] Example 5

[0093] It is basically the same as Example 1, except that:

[0094] (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;

[0095] (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.

[0096] Example 6

[0097] It is basically the same as Example 1, except that:

[0098] (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;

[0099] (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.

[0100] Example 7

[0101] It is basically the same as Example 3, 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 8

[0105] It is basically the same as Example 3, 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] Comparative Example: Commercially available gold-plated copper bonding wire with a diameter of 30 μm.

[0109] Test Example 1

[0110] The breaking force and elongation of the 30 μm gold-copper bonding wire of each embodiment and the commercially available 30 μm gold-plated copper bonding wire of the comparative example were measured using a YG001 B single fiber electronic strength tester. Ten samples were taken from each embodiment and the comparative example for testing, and the average values ​​were taken and recorded in Table 1.

[0111] Table 1

[0112] Breaking force(cN) Elongation(%) Example 1 11.3 12.1 Example 2 11.1 12.5 Example 3 11.5 12.7 Example 4 11.7 12.2 Example 5 11.2 12.8 Example 6 11.6 12.1 Example 7 12.4 12.7 Example 8 11.9 12.6 Comparative Example 1 10.2 9.3

[0113] As can be seen from Table 1, the breaking force and elongation of the gold-copper bonding wire prepared by the present invention are higher than those of the commercially available gold-plated copper bonding wire. It is worth noting that in the wire bonding process, the working conditions of the bonding wire are very complex, especially for the bonding wire on the high-speed automatic bonding machine, which requires the bonding wire to have a higher breaking force and elongation. For the bonding wire, its breaking force and elongation play a key role in the quality of wire bonding, and a bonding wire with high breaking force and elongation is more conducive to bonding.

[0114] Test Example 2

[0115] The gold-copper bonding wire with a diameter of 30 μm in Example 1 of the present invention was further drawn, with a single deformation rate of 6% and a drawing speed of 20 m / s to obtain a gold-copper bonding wire with a diameter of 20 μm. The surface of the drawn gold-copper bonding wire was observed by scanning electron microscopy, as shown in FIG. Figure 1 The SEM image provided is shown, which shows that the coating surface is flat, smooth, uniform and consistent without any obvious defects.

[0116] 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 with a diameter of 8 mm to 20 mm and a gold tube with an inner diameter of 8 mm to 20 mm, wherein the single crystal copper rod and the gold tube have the same length; (b) a gold rod with a diameter of 2 mm to 10 mm, a single crystal copper tube with an inner diameter of 2 mm to 10 mm, and a gold tube with an inner diameter of 4 mm to 15 mm, wherein the gold rod, the single crystal copper tube, and the gold tube have the same length; (2) assembling the metal raw materials, and then electron beam welding the dissimilar metal contact lines on the assembled cross section to obtain a composite blank; (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 (a), the inner diameter of the gold tube is ≥ the diameter of the copper rod; Preferably, the difference between the inner diameter of the gold tube and the diameter of the copper rod is 0.01 mm to 0.05 mm.

3. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: For (a), the wall thickness of the gold tube is 2 mm to 3 mm; And / or, for (b), the wall thicknesses of the single crystal copper tube and the gold tube are independently selected from 2 mm to 3 mm.

4. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The inner diameter of the single crystal copper tube is greater than or equal to the diameter of the gold rod, and the inner diameter of the gold tube is greater than or equal to the outer diameter of the single crystal copper tube; Preferably, the difference between the inner diameter of the single crystal copper tube and the diameter of the gold rod is 0.01 mm to 0.05 mm, and the difference between the inner diameter of the gold tube and the outer diameter of the single crystal copper tube is 0.01 mm to 0.05 mm.

5. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: For (a), the inner and outer surface roughness of the single crystal copper rod and / or the gold tube is Ra0.2 to Ra3.2; Alternatively, for (b), the inner and outer surface roughness of the gold rod, the single crystal copper tube and the gold tube are independently selected from Ra0.2 to Ra1.

6.

6. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: The welding current of the electron beam welding is 5mA to 20mA, and the welding speed is 50mm / min to 100mm / min; And the electron beam welding is performed under vacuum conditions.

7. The method for preparing a gold-copper bonding wire according to claim 1, characterized in that: For (a), the single crystal copper rod is inserted into the pipe of the gold tube, and the dissimilar metal contact wires on the assembled cross section are electron beam welded to obtain a composite blank; Alternatively, for (b), the gold rod is first inserted into the tube of the single crystal copper tube, and then the two are inserted into the tube of the gold tube together, and the dissimilar metal contact wires on the assembled cross section are electron beam welded to obtain the composite blank.

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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