A method for welding an embedded copper wire

Abstract

The present application relates to a kind of welding methods of embedded copper wire, the welding method includes the following steps: (1) first welding part and second welding part are processed first recess and second recess respectively, copper wire is placed into first recess, the second welding part containing second recess is placed on the top of first welding part, the opening direction of first recess and second recess is relatively arranged and copper wire is located in the space between first recess and second recess, to obtain the assembled welding structure;(2) the welding structure of step (1) is diffusion welded, to obtain the welding piece of embedded copper wire.The welding method provided by the present application can ensure high welding strength and stable welding quality by designing and optimizing the welding structure and using diffusion welding.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and more specifically to a welding method for embedding copper wire. Background Technology

[0002] Embedded copper wire components typically refer to copper wires or copper foil conductors embedded inside a device and fixed by welding, thereby achieving electrical connection or transmitting electrical signals. Copper wire has excellent conductivity, enabling efficient transmission of current and signals; it also has high thermal conductivity, aiding in heat dissipation or device heating; and its compact structure meets the requirements of limited internal space in devices. Copper wires are usually connected to the internal structure of the device by welding, resulting in a stable connection and reducing the risk of circuit failure. Embedded copper wire components are commonly used for internal conductors on circuit boards, interlayer connections on circuit boards, package leads in chips, or heating structures, and are widely used in electronic devices, semiconductor devices, integrated circuits, and other fields.

[0003] Currently, commonly used welding methods mainly include diffusion welding and vacuum brazing. Vacuum brazing is performed in a vacuum heating chamber, utilizing the evaporation of the filler metal under high temperature and high vacuum conditions to form a gas, creating a new metallic material on the brazed surface, thus achieving a brazed joint. However, vacuum brazing suffers from low weld strength and is prone to defects such as incomplete welds and porosity within the brazed seam. Diffusion welding involves pressing two workpieces together and heating them in a vacuum or protective atmosphere furnace, causing microscopic plastic deformation on the weld surface to achieve close contact. Further atomic diffusion occurs during the heating and holding process, forming a stable weld structure.

[0004] In existing welding processes for embedded copper wire components, it is typically necessary to first machine an inner groove for the embedded copper wire. After embedding the wire, a certain distance exists between the wire and the welding surface, preventing it from being welded flush. Therefore, an insert is added above the wire to ensure flush welding of the upper and lower welding surfaces. However, the introduction of the insert increases and widens the gaps between components, leading to poor welding. Furthermore, since the welding status of the embedded component cannot be directly observed from the outside, it is difficult to monitor and control the welding quality in real time.

[0005] Therefore, providing a welding structure and welding method suitable for copper wire embedded parts is a technical problem that needs to be solved in this field. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a welding method for embedded copper wire. Compared with the prior art, the welding method provided by the present invention, through the design and optimization of the welding structure and the adoption of diffusion welding, can ensure high welding strength and stable welding quality.

[0007] To achieve this objective, the present invention adopts the following technical solution: This invention provides a welding method for embedded copper wire, the welding method comprising the following steps: (1) The first welding part and the second welding part are respectively processed into the first groove and the second groove. The copper wire is placed in the first groove and the second welding part containing the second groove is placed above the first welding part, so that the opening directions of the first groove and the second groove are opposite and the copper wire is located in the space between the first groove and the second groove, thus obtaining the assembled welding structure. (2) The welding structure obtained in step (1) is subjected to diffusion welding to obtain a welded part with embedded copper wire.

[0008] The welding method provided by this invention targets the welding process of copper wire embedded parts. On one hand, grooves are machined into the first and second welding parts respectively, allowing the copper wire to be placed inside these grooves. By controlling the shape and size of the grooves, good contact between the copper wire and the welding surfaces of both the first and second welding parts can be achieved without the use of inserts, thus ensuring welding effectiveness and avoiding the problems of excessive gaps and uncontrollable gaps caused by too many components in existing processes, which lead to decreased weld strength. On the other hand, based on the above welding structure design, this invention employs diffusion welding. Under controlled diffusion welding pressure, the upper welding surface of the copper wire fully contacts and diffuses with the highest point of the second groove, while the lower welding surface of the copper wire fully contacts and diffuses with the lowest point of the first groove. This ultimately achieves a high weld bonding rate and weld bonding strength, effectively ensuring welding quality and stability.

[0009] Preferably, the diameter of the copper wire in step (1) is 5.9-6.1 mm, for example, it can be 5.9 mm, 5.95 mm, 6 mm, 6.05 mm or 6.1 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] Preferably, in step (1), the opening profile of the cross-section of the first groove is a U-shaped structure.

[0011] Preferably, the opening width of the U-shaped structure accounts for 100-107% of the diameter of the copper wire. For example, it can be 100%, 101%, 102%, 103%, 104%, 105%, 106%, or 107%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, the depth of the copper wire placed in the first groove is 60-70% of the diameter of the copper wire, for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% or 70%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] In this invention, it is preferable to control the depth of the copper wire placed in the first groove to be a percentage of the copper wire diameter within a specific range, which helps to reduce the gap size and thus avoid the problem of poor welding effect caused by excessive gap.

[0014] Preferably, the gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is 0-0.1mm, for example, it can be 0mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm or 0.1mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the material of the first welded part in step (1) includes aluminum.

[0016] Preferably, in step (1), the opening profile of the cross-section of the second groove is an arc-shaped structure.

[0017] In this invention, the length direction of the first groove and the second groove is parallel to the length direction of the copper wire, so that the first groove and the second groove can embed the copper wire. The "cross section" mentioned in this invention refers to a cross section that is perpendicular to the length direction of the first groove or the second groove.

[0018] Preferably, the opening width of the arc-shaped structure accounts for 100-107% of the diameter of the copper wire. For example, it can be 100%, 101%, 102%, 103%, 104%, 105%, 106%, or 107%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] In this invention, it is preferable to control the percentage of the opening width of the arc-shaped structure to the diameter of the copper wire and the percentage of the opening width of the U-shaped structure to the diameter of the copper wire within a specific range. More preferably, it is preferable to control the opening size and opening range of the two to be consistent, which can avoid the problem of poor welding effect caused by too much gap or too large gap.

[0020] Preferably, the depth of the copper wire placed in the second groove is 30-40% of the diameter of the copper wire, for example, it can be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] In this invention, it is preferable to control the depth of the copper wire placed in the second groove to a certain percentage of the copper wire diameter, which helps to reduce the gap size and thus avoid the problem of poor welding effect caused by excessive gap.

[0022] Preferably, the gap between the top of the copper wire and the highest point of the second groove is 0-0.1mm, for example, it can be 0mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm or 0.1mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the material of the second welded part in step (1) includes aluminum.

[0024] Preferably, before diffusion welding in step (2), the welded structure is placed in a sleeve for degassing treatment; Preferably, the temperature of the degassing treatment is 210-230℃, for example, it can be 210℃, 212℃, 214℃, 216℃, 218℃, 220℃, 222℃, 224℃, 226℃, 228℃ or 230℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] Preferably, the final vacuum degree of the degassing treatment is 1×10⁻⁶. -4 -1×10 -3 Pa, for example, could be 1×10 -4 Pa, 2×10 -4 Pa, 3×10 -4 Pa, 4×10 -4 Pa, 5×10 -4 Pa, 6×10 -4 Pa, 7×10 -4 Pa, 8×10 -4 Pa, 9×10 -4 Pa or 1×10 -3 Pa, but not limited to the listed values, applies to other unlisted values ​​within the range as well.

[0026] Preferably, the diffusion welding temperature in step (2) is 270-290℃, for example, it can be 270℃, 271℃, 272℃, 273℃, 274℃, 275℃, 276℃, 277℃, 278℃, 279℃, 280℃, 281℃, 282℃, 283℃, 284℃, 285℃, 286℃, 287℃, 289℃ or 290℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0027] Preferably, the holding time for diffusion welding is 10-20 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the diffusion welding pressure in step (2) is 100-120 MPa, for example, it can be 100 MPa, 102 MPa, 104 MPa, 106 MPa, 108 MPa, 110 MPa, 112 MPa, 114 MPa, 116 MPa, 118 MPa or 120 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] In this invention, the pressure of diffusion welding is preferably controlled within a specific range, which can induce microscopic plastic deformation at the welding contact surface, thereby achieving close contact and further causing interatomic diffusion, ultimately forming a stable welded structure.

[0030] As a preferred embodiment of the present invention, the welding method includes the following steps: (1) The first welding part and the second welding part are respectively processed into a first groove and a second groove. The opening profile of the cross section of the first groove is a U-shaped structure. The opening width of the U-shaped structure accounts for 100-107% of the diameter of the copper wire. The opening profile of the cross section of the second groove is an arc-shaped structure. The opening width of the arc-shaped structure accounts for 100-107% of the diameter of the copper wire. A copper wire with a diameter of 5.9-6.1mm is placed into the first groove. The depth of the copper wire in the first groove accounts for 60-70% of the diameter of the copper wire. The fit gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is 0-0.1mm. The second welding part containing the second groove is placed above the first welding part, so that the opening directions of the first groove and the second groove are opposite and the copper wire is located in the space between the first groove and the second groove. The depth of the copper wire in the second groove accounts for 30-40% of the diameter of the copper wire. The fit gap between the top of the copper wire and the highest point of the top of the second groove is 0-0.1mm. The assembled welding structure is obtained. (2) Place the welded structure obtained in step (1) into a sleeve and degas it at a temperature of 210-230℃ until the final vacuum degree is 1×10⁻⁶. -4 -1×10 -3 Pa, and then diffusion welding is performed for 10-20 minutes at a temperature of 270-290℃ and a pressure of 100-120MPa to obtain a welded part with embedded copper wire.

[0031] Compared with the prior art, the present invention has the following beneficial effects: (1) By designing the shape and size of the first groove and the second groove, the present invention can achieve good contact between the welding surface of the copper wire and the first welding part and the welding surface of the copper wire and the second welding part without the use of inserts, thereby ensuring the welding effect and avoiding the problem of excessive gaps and large gaps that are difficult to control due to too many components in the existing process, which leads to a decrease in the welding bond strength. The present invention achieves the optimization and improvement of the welding structure.

[0032] (2) The present invention adopts diffusion welding method, under the condition of controlling diffusion welding pressure, the upper welding surface of copper wire is fully in contact with the highest point of the second groove and diffuses, while the lower welding surface of copper wire is fully in contact with the lowest point of the first groove, thereby achieving a high welding bonding rate and welding bonding strength, effectively ensuring the quality and stability of welding. Attached Figure Description

[0033] Figure 1 This is a schematic cross-sectional view of the welded structure described in Embodiment 1 of the present invention; Figure 2 This is a schematic cross-sectional view of the welding structure described in Comparative Example 1 of the present invention; Wherein, 1-first welding part; 2-second welding part; 3-copper wire; 4-insert. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0035] Example 1 This embodiment provides a welding method for embedded copper wire, the welding method including the following steps: (1) such as Figure 1As shown, a first welding part 1 and a second welding part 2, both made of aluminum, are respectively machined into a first groove and a second groove. The opening profile of the cross-section of the first groove is a U-shaped structure with an opening width of 6.4 mm. The opening profile of the cross-section of the second groove is an arc-shaped structure with an opening width of 6.4 mm. A copper wire 3 with a diameter of 6 mm is placed into the first groove to a depth of 3.8 mm. The gap between the bottom of the copper wire 3 and the lowest point of the bottom of the first groove is 0.05 mm. The second welding part 2, containing the second groove, is placed above the first welding part 1, so that the opening directions of the first and second grooves are opposite, the opening ranges are consistent, and the copper wire 3 is located in the space between the first and second grooves. The depth of the copper wire 3 in the second groove is 2.2 mm. The gap between the top of the copper wire 3 and the highest point of the top of the second groove is 0.05 mm, resulting in the assembled welded structure. (2) Place the welded structure obtained in step (1) into a sleeve and degas it at a temperature of 220°C until the final vacuum degree is 2×10⁻⁶. -4 Pa, and then diffusion welding was performed for 15 minutes at a temperature of 280℃ and a pressure of 110MPa to obtain the welded part with embedded copper wire 3.

[0036] Example 2 This embodiment provides a welding method for embedded copper wire, the welding method including the following steps: (1) The first welding part and the second welding part, which are made of aluminum, are respectively processed into a first groove and a second groove. The opening profile of the cross section of the first groove is a U-shaped structure with an opening width of 6.2 mm. The opening profile of the cross section of the second groove is an arc-shaped structure with an opening width of 6.2 mm. A copper wire with a diameter of 6 mm is placed in the first groove. The depth of the copper wire in the first groove is 3.6 mm. The fit gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is 0.03 mm. The second welding part containing the second groove is placed above the first welding part, so that the opening directions of the first groove and the second groove are opposite, the opening range is the same, and the copper wire is located in the space between the first groove and the second groove. The depth of the copper wire in the second groove is 2.4 mm. The fit gap between the top of the copper wire and the highest point of the top of the second groove is 0.03 mm. The assembled welding structure is obtained. (2) Place the welded structure obtained in step (1) into a sleeve and degas it at a temperature of 210°C until the final vacuum degree is 3×10⁻⁶. -4 Pa, and then diffusion welding was performed for 10 minutes at a temperature of 270℃ and a pressure of 120MPa to obtain a welded part with embedded copper wire.

[0037] Example 3 This embodiment provides a welding method for embedded copper wire, the welding method including the following steps: (1) The first welding part and the second welding part, which are made of aluminum, are respectively processed into a first groove and a second groove. The opening profile of the cross section of the first groove is a U-shaped structure with an opening width of 6.3 mm. The opening profile of the cross section of the second groove is an arc-shaped structure with an opening width of 6.3 mm. A copper wire with a diameter of 6 mm is placed in the first groove. The depth of the copper wire in the first groove is 4.2 mm. The fit gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is 0.04 mm. The second welding part containing the second groove is placed above the first welding part, so that the opening directions of the first groove and the second groove are opposite, the opening range is the same, and the copper wire is located in the space between the first groove and the second groove. The depth of the copper wire in the second groove is 1.8 mm. The fit gap between the top of the copper wire and the highest point of the top of the second groove is 0.04 mm. The assembled welding structure is obtained. (2) Place the welded structure obtained in step (1) into a sleeve and degas it at a temperature of 230°C until the final vacuum degree is 5×10⁻⁶. -4 Pa, and then diffusion welding was performed for 20 minutes at a temperature of 290℃ and a pressure of 100MPa to obtain a welded part with embedded copper wire.

[0038] Example 4 This embodiment provides a welding method for embedded copper wire, which differs from Embodiment 1 only in that the opening width of the U-shaped structure and the opening width of the arc-shaped structure are both 6.6 mm.

[0039] Example 5 This embodiment provides a welding method for embedded copper wire, which differs from Embodiment 1 only in that the fit gap between the bottom of the copper wire and the lowest point of the first groove is 0.5mm.

[0040] Example 6 This embodiment provides a welding method for embedded copper wire. The only difference from Embodiment 1 is that the fit gap between the top of the copper wire and the highest point of the second groove is 0.5mm.

[0041] Example 7 This embodiment provides a welding method for embedded copper wire, which differs from Embodiment 1 only in that the diffusion welding pressure is 95 MPa.

[0042] Example 8 This embodiment provides a welding method for embedded copper wire, which differs from Embodiment 1 only in that the diffusion welding pressure is 130 MPa.

[0043] Comparative Example 1 This comparative example provides a welding method for embedded copper wire, the only difference from Example 1 is that the welding structure is replaced with... Figure 2 The welding structure shown has a flat bottom welding surface for the second welding part 2 without a second groove. An insert 4 is placed between the second welding part 2 and the copper wire 3. The bottom of the insert 4 has a third groove with an arc-shaped opening. The top of the insert 4 is flat and located below the second welding part 2. Both the insert 4 and the copper wire 3 are placed in the first groove of the first welding part 1. The clearance between the bottom of the copper wire 3 and the lowest point of the bottom of the first groove is 0.05 mm. The clearance between the top of the copper wire 3 and the highest point of the top of the third groove is 0.05 mm. The distance between the highest point of the top of the third groove and the top surface of the insert 4 is 3 mm.

[0044] The welding bonding rate of the welded parts obtained in Examples 1-8 and Comparative Example 1 was measured using an ultrasonic flaw detector, and the results are shown in Table 1.

[0045] The weld bond strength of the welded parts obtained in Examples 1-8 and Comparative Example 1 was determined by tensile testing, and the results are shown in Table 1.

[0046] Table 1 The following points can be observed from the data in Table 1: (1) As can be seen from the data of Examples 1-8, the welding method provided by the present invention can achieve a welding bonding rate of more than 96.71%, and under better conditions, it can achieve more than 99.97%, and the welding bonding strength can reach more than 23 MPa, and under better conditions, it can reach more than 32 MPa.

[0047] (2) By comparing the data of Example 1 and Example 4-6, it can be seen that the difference between Example 4-6 and Example 1 is that the opening width of the U-shaped structure and the opening width of the arc structure are not within the preferred range of the present invention, the fitting gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is not within the preferred range of the present invention, or the fitting gap between the top of the copper wire and the highest point of the top of the second groove is not within the preferred range of the present invention. The welding strength and welding rate in Example 1 are significantly better than those in Example 4-6. It can be seen that the present invention can further improve the welding effect by preferentially controlling the shape and size of the first groove and the second groove.

[0048] (3) Comparing the data of Examples 7-8, it can be seen that the only difference between Examples 7-8 and Example 1 is that the pressure of diffusion welding is not within the preferred range of the present invention. The welding bond strength and welding bond rate in Example 1 are significantly better than those in Examples 7-8. It can be seen that the present invention can further improve the welding effect by preferentially controlling the pressure of diffusion welding.

[0049] (4) By comparing the data of Example 1 and Comparative Example 1, it can be seen that the welding strength and welding rate of Example 1 are significantly better than those of Comparative Example 1, which introduces a welding structure containing inserts. Therefore, the welding structure provided by the present invention can further improve the welding effect.

[0050] In summary, the welding method provided by this invention, through the design and optimization of the weld structure and the adoption of diffusion welding, can ensure high welding strength and stable welding quality.

[0051] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A welding method for embedded copper wire, characterized in that, The welding method includes the following steps: (1) The first welding part and the second welding part are respectively processed into the first groove and the second groove. The copper wire is placed in the first groove and the second welding part containing the second groove is placed above the first welding part, so that the opening directions of the first groove and the second groove are opposite and the copper wire is located in the space between the first groove and the second groove, thus obtaining the assembled welding structure. Step (1) The opening profile of the cross-section of the first groove is a U-shaped structure; the opening width of the U-shaped structure accounts for 100-107% of the diameter of the copper wire; the depth of the copper wire placed in the first groove accounts for 60-70% of the diameter of the copper wire; the fit gap between the bottom of the copper wire and the lowest point of the bottom of the first groove is 0-0.1mm; Step (1) The opening profile of the cross-section of the second groove is an arc-shaped structure; the opening width of the arc-shaped structure accounts for 100-107% of the diameter of the copper wire; the depth of the copper wire placed in the second groove accounts for 30-40% of the diameter of the copper wire; the fit gap between the top of the copper wire and the highest point of the top of the second groove is 0-0.1mm; (2) The welding structure obtained in step (1) is subjected to diffusion welding to obtain a welded part with embedded copper wire; The temperature of diffusion welding in step (2) is 270-290℃; the holding time of diffusion welding is 10-20min; and the pressure of diffusion welding is 100-120MPa.

2. The welding method according to claim 1, characterized in that, The diameter of the copper wire in step (1) is 5.9-6.1 mm.

3. The welding method according to claim 1, characterized in that, Step (1) The material of the first welded part includes aluminum.

4. The welding method according to claim 1, characterized in that, Step (1) The material of the second welded part includes aluminum.

5. The welding method according to claim 1, characterized in that, Before diffusion welding in step (2), the welded structure is placed in a sleeve for degassing treatment.

6. The welding method according to claim 5, characterized in that, The degassing treatment temperature is 210-230℃.

7. The welding method according to claim 5, characterized in that, The final vacuum degree of the degassing process is 1×10⁻⁶. -4 -1×10 -3 Pa.

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