Copper-palladium alloy single-crystal bonding wire and manufacturing method thereof

Abstract

The invention relates to the technical field of metal bonding wires, in particular to a copper-palladium alloy single-crystal bonding wire and a manufacturing method thereof. The invention relates to a copper-palladium alloy single crystal bonding wire, which comprises the following components in percentage by weight: 3.50 to 9.50 percent of palladium, 0.0005 to 0.0008 percent of calcium, 0.0002 to 0.0005 percent of beryllium, 0.0001 to 0.0005 percent of rhenium and the balance of copper. The invention discloses a manufacturing method of a copper-palladium alloy single-crystal bonding wire. The manufacturing method comprises the following steps: S1, preparing a single-crystal copper-palladium alloy rod; s2, rough drawing; s3, primary annealing; s4, plating palladium on the surface; s5, continuously drawing; s6, secondary annealing; and S7, cleaning. The copper-palladium alloy single-crystal bonding wire is subjected to secondary annealing through the specially-made annealing device, so that the physical strength of the copper-palladium alloy single-crystal bonding wire is improved, the tensile property of the copper-palladium alloy single-crystal bonding wire is improved, and the wire breakage problem is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metal bonding wires, in particular to a copper-palladium alloy single crystal bonding wire and a manufacturing method thereof. Background Art

[0002] Early bonding wires were mostly made of pure gold, but with the increasing scarcity of gold resources and the continuous rise in prices, the cost of microelectronic packaging has risen sharply. For this reason, industry insiders have successfully developed copper wire products to replace expensive gold wire products. These bonding copper wires are inexpensive and have better performance than gold wires in terms of tensile strength, shear strength and ductility. They have been successfully used in the packaging production of products such as DIP, SOP and power devices. However, as the microelectronic device chip industry is increasingly and rapidly developing towards miniaturization, multi-pin high density, the performance requirements for bonding copper wires are becoming more and more stringent, especially in the bonding process. Not only are the bonding copper wires required to have good high-temperature oxidation resistance, heat stability and high mechanical strength, but they must also have good bonding and weldability and must not have the problem of wire breakage due to pulling; in addition, due to the increase in packaging density and the increase in the number of wires, in addition to further reducing the wire diameter of the bonding copper wire, it is also necessary to cover the surface of the copper wire with an insulating layer to reduce the occurrence of short circuits. At present, some people in the industry have used the bonding copper wire manufacturing process of replacing the electroplated gold layer with the electroplated palladium layer, but the existing palladium-plated bonding copper wire has not been able to solve the problem of the palladium-plated bonding copper wire being broken during pulling. Therefore, the present application provides a copper-palladium alloy single crystal bonding wire and a manufacturing method thereof, which solves the problem of poor tensile strength and easy wire breaking of the copper-palladium alloy single crystal bonding wire in the prior art, and improves the mechanical properties of the copper-palladium alloy single crystal bonding wire. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a copper-palladium alloy single crystal bonding wire and a manufacturing method thereof.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a copper-palladium alloy single crystal bonding wire, which includes the following components by weight: 3.50%-9.50% palladium, 0.0005%-0.0008% calcium, 0.0002%-0.0005% beryllium, 0.0001%-0.0005% rhenium, and the rest is copper.

[0005] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Surface palladium plating, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, the coating thickness is 1-5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 15-35 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled 2-3 times and washed with water 2-3 times, and then dried.

[0006] As an optimization, the annealing device A includes an annealing device body, a spiral annealing channel is provided inside the annealing device body, a heating rod is provided inside the annealing device body, a heat conduction gap is left between the heating rod and the annealing device body, an air inlet is provided at the upper end of the heat conduction gap, a fan is connected between the lower end of the heat conduction gap and the lower end of the annealing channel, and the hot air inside the heat conduction gap pushes the copper-palladium alloy single crystal bonding wire in the annealing channel upward from bottom to top through the fan.

[0007] As an optimization, a driving interlayer is provided inside the main body of the annealing device, a driving layer is provided inside the driving interlayer, the annealing channel is located on the inner wall of the driving interlayer, and the copper-palladium alloy single crystal bonding wire in the annealing channel is in contact with the driving layer; The annealing device body is provided with a driving motor, the output shaft of the driving motor is connected with a driving roller, and the driving roller is in contact with the circumferential surface of the driving interlayer.

[0008] As an optimization, the annealing device body includes a preheating section and a heating section. The heating section is connected to the top of the preheating section. The distance between the annealing channel of the preheating section and the heating rod gradually decreases from bottom to top, and the distance between the annealing channel of the heating section and the heating rod is uniform and unchanged.

[0009] As an optimization, a heating chamber is opened in the axial direction of the annealing device body, and the heating rod is located in the heating chamber.

[0010] As an optimization, a connecting section is provided at the lower end of the preheating section, and both the connecting section and the heating section are cylindrical.

[0011] The present invention provides a copper-palladium alloy single crystal bonding wire and a method for manufacturing the same, which has the following advantages: The copper-palladium alloy single crystal bonding wire of the present application reasonably optimizes the ratio of various elements, and performs secondary annealing on the copper-palladium alloy single crystal bonding wire through a special annealing device, thereby achieving the physical strength of the copper-palladium alloy single crystal bonding wire crystal, thereby improving the tensile properties of the copper-palladium alloy single crystal bonding wire and reducing the occurrence of wire breakage problems; In the annealing device of the present application, different annealing temperatures are achieved by setting different distances between the copper-palladium alloy single crystal bonding wire and the heating element, thereby improving the tensile properties of the copper-palladium alloy single crystal bonding wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an axial schematic diagram of the main body of the annealing device of the present invention.

[0013] Figure 2 It is a schematic diagram of the bottom axial side of the annealing device body of the present invention.

[0014] Figure 3 It is a schematic front view of the main body of the annealing device of the present invention.

[0015] Figure 4 For the present invention Figure 3 Schematic diagram of the AA section structure.

[0016] Among them, 1. annealing device body, 2. annealing channel, 3. heating rod, 4. heat conduction interval, 5. air inlet, 6. fan, 7. driving layer, 8. driving motor, 9. driving roller, 10. preheating section, 11. heating section. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0018] Embodiment 1: A copper-palladium alloy single crystal bonding wire comprises the following components by weight: 3.50% palladium, 0.0005% calcium, 0.0002% beryllium, 0.0001% rhenium, and the remainder is copper.

[0019] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Palladium plating on the surface, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, and the coating thickness is 1.5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 17 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled three times and washed with water three times, and then dried.

[0020] Embodiment 2: A copper-palladium alloy single crystal bonding wire comprises the following components by weight: 9.5% palladium, 0.0008% calcium, 0.0005% beryllium, 0.0005% rhenium, and the remainder is copper.

[0021] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Surface palladium plating, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, and the coating thickness is 5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 35 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled three times and washed with water three times, and then dried.

[0022] Embodiment 3: A copper-palladium alloy single crystal bonding wire comprises the following components by weight: 6.50% palladium, 0.07% calcium, 0.0003% beryllium, 0.0003% rhenium, and the remainder is copper.

[0023] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Palladium plating on the surface, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, and the coating thickness is 3μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 24 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled three times and washed with water three times, and then dried.

[0024] Comparative Example 1: A copper-palladium alloy single crystal bonding wire comprises the following components by weight: 3.50% palladium, 0.0005% calcium, 0.0002% beryllium, 0.0001% rhenium, and the remainder is copper.

[0025] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. An annealing step, wherein the single crystal copper-palladium alloy obtained in step S2 is annealed once at a temperature of 350°C-460°C; S4. Palladium plating on the surface, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, and the coating thickness is 1.5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 15 μm; S6. Secondary annealing, the copper-palladium alloy single crystal bonding filament obtained in step S5 is subjected to secondary annealing at an annealing temperature of 270°C-345°C; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled three times and washed with water three times, and then dried.

[0026] Comparative Example 2: A copper-palladium alloy single crystal bonding wire comprises the following components by weight: 3.50% palladium, 0.0005% calcium, 0.0001% rhenium, and the remainder is copper.

[0027] A method for manufacturing a copper-palladium alloy single crystal bonding wire comprises the following steps: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium and rhenium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Palladium plating on the surface, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, and the coating thickness is 1.5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 15 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled three times and washed with water three times, and then dried.

[0028] The mechanical properties of the copper-palladium alloy single crystal bonding filaments obtained in Example 1-3 and Comparative Example 1-2 were tested, and the test results are as follows: Breaking force (≥5g) Hardness (Hv001) Tensile strength (≥210MPa) Example 17.71100241 Example 27.82101245 Example 37.76101243 Comparative Example 15.3396233 Comparative Example 25.7796236 By comparing Example 1 with Comparative Example 2, it can be seen that the copper-palladium alloy single crystal bonding filament of the present application is compared with Comparative Example 2, and the scientific addition of an appropriate amount of beryllium element can effectively improve the various mechanical properties of the copper-palladium alloy single crystal bonding filament. By comparing the embodiment with Comparative Example 1, it can be seen that the copper-palladium alloy single crystal bonding filament is annealed twice by the annealing device A and the annealing device B of the present application, which effectively improves the mechanical properties of the copper-palladium alloy single crystal bonding filament, improves the tensile properties of the copper-palladium alloy single crystal bonding filament, and reduces the break rate.

[0029] like Figure 1-4 As shown, the annealing device A includes an annealing device body 1, a spiral annealing channel 2 is provided inside the annealing device body 1, a heating rod 3 is provided inside the annealing device body 1, a heat conduction gap 4 is left between the heating rod 3 and the annealing device body 1, an air inlet 5 is provided at the upper end of the heat conduction gap 4, a fan 6 is connected between the lower end of the heat conduction gap 4 and the lower end of the annealing channel 2, and the hot air inside the heat conduction gap 4 pushes the copper-palladium alloy single crystal bonding wire in the annealing channel 2 upward from bottom to top through the fan 6.

[0030] Under the action of the fan 6, the external air enters the heat-conducting air layer, and the hot air in the heat-conducting insulation layer passes downward through the fan 6 into the annealing channel 2, and the hot air can preheat the copper-palladium alloy single crystal bonding filament from bottom to top. The copper-palladium alloy single crystal bonding filament in the annealing channel 2 moves from bottom to top in a spiral shape, and the hot air can push the copper-palladium alloy single crystal bonding filament to move upward to a certain extent, offsetting part of the friction between the copper-palladium alloy single crystal bonding filament and the annealing device body 1, and promoting efficient annealing of the copper-palladium alloy single crystal bonding filament.

[0031] like Figure 1 and Figure 4 As shown, a driving interlayer is provided inside the annealing device body 1, a driving layer 7 is provided inside the driving interlayer, the annealing channel 2 is located on the inner wall of the driving interlayer, and the copper-palladium alloy single crystal bonding wire in the annealing channel 2 is in contact with the driving layer 7; like Figure 1 and Figure 4 As shown, the annealing device body 1 is provided with a driving motor 8, the output shaft of the driving motor 8 is connected with a driving roller 9, and the driving roller 9 is in contact with the circumferential surface of the driving interlayer.

[0032] The driving layer 7 is used to drive the copper-palladium alloy single crystal bonding wire to move upward, so that the copper-palladium alloy single crystal bonding wire is evenly heated, and the copper-palladium alloy single crystal bonding wire is prevented from being broken during the movement.

[0033] like Figure 1 and Figure 4As shown, the annealing device body 1 includes a preheating section 10 and a heating section 11. The heating section 11 is connected to the top of the preheating section 10. The distance between the preheating section 10 and the heating rod 3 gradually decreases from bottom to top, and the distance between the heating section 11 and the heating rod 3 is uniform and unchanged.

[0034] The annealing device A and the annealing device B have the same structure. In the annealing device A, the temperature of the preheating section 10 is 350°C-420°C, and the temperature of the heating section 11 is 420°C-460°C. In the annealing device B, the temperature of the preheating section 10 is 270°C-320°C, and the temperature of the heating section 11 is 320°C-345°C.

[0035] like Figure 1 and Figure 4 As shown, a heating chamber is provided in the axial direction of the annealing device body 1, and the heating rod 3 is located in the heating chamber.

[0036] The outer circumference of the heating rod 3 is evenly connected with a plurality of heat-conducting fins, and the plurality of heat-conducting fins are vertically arranged.

[0037] like Figure 1 As shown, a connecting section is provided at the lower end of the preheating section 10, and the connecting section and the heating section 11 are both cylindrical.

[0038] When the device is used, the copper-palladium alloy single crystal bonding filament is inserted into the annealing channel 2 from bottom to top; The fan 6 is running, so that the external air enters the heat-conducting insulation layer from top to bottom, and the hot air enters the annealing channel 2 from bottom to top through the fan 6, and efficiently contacts the copper-palladium alloy single crystal bonding filament, pushing the copper-palladium alloy single crystal bonding filament to move upward; The driving motor 8 drives the driving roller 9 to rotate, the driving roller 9 drives the driving layer 7 to rotate, and the driving layer 7 drives the copper-palladium alloy single crystal bonding filament to spiral upward; During the process of the annealing device main body 1 rotating and rising, the copper-palladium alloy single crystal bonding wire is uniformly preheated and heated, thereby improving the annealing effect and the mechanical properties of the copper-palladium alloy single crystal bonding wire.

[0039] The above-mentioned specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the product form and style of the above-mentioned specific embodiments. Any copper-palladium alloy single crystal bonding wire and its manufacturing method that conform to the claims of the present invention and any appropriate changes or modifications made thereto by ordinary technicians in the corresponding technical field shall fall within the patent protection scope of the present invention.

Claims

1. A copper-palladium alloy single crystal bonding wire, characterized in that: Calculated by weight, it includes the following components: 3.50%-9.50% palladium, 0.0005%-0.0008% calcium, 0.0002%-0.0005% beryllium, 0.0001%-0.0005% rhenium, and the rest is copper.

2. A method for manufacturing a copper-palladium alloy single crystal bonding wire, used to produce the copper-palladium alloy single crystal bonding wire according to claim 1, characterized in that: The steps include: S1. preparing a single crystal copper-palladium alloy rod, adding copper, palladium, calcium, rhenium and beryllium into a metal single crystal continuous casting chamber, and continuously casting to obtain a high-purity copper-palladium alloy rod; S2. Rough drawing, drawing the high-purity copper-palladium alloy rod obtained in step S1 to obtain a single crystal copper-palladium alloy wire with a diameter of less than 1 mm; S3. Primary annealing, wherein the single crystal copper-palladium alloy wire obtained in step S2 is inserted into the annealing device A for primary annealing; S4. Surface palladium plating, adding high-purity palladium with a purity of not less than 99.999% to the inside of the electroplating device, palladium plating the single crystal copper-palladium alloy wire after the first annealing in step S3, the coating thickness is 1-5μm; S5. Continue drawing to precisely draw the copper-palladium alloy wire with a pure palladium coating to obtain a copper-palladium alloy single crystal bonding wire with a diameter of 15-35 μm; S6. Secondary annealing, introducing the copper-palladium alloy single crystal bonding filament obtained in step S5 into the annealing device B for continuous annealing; S7. Cleaning: The copper-palladium alloy single crystal bonding filament after annealing in step S6 is pickled 2-3 times and washed with water 2-3 times, and then dried.

3. The method for manufacturing a copper-palladium alloy single crystal bonding wire according to claim 2, characterized in that: The annealing device A comprises an annealing device body (1), a spiral annealing channel (2) is provided inside the annealing device body (1), a heating rod (3) is provided inside the annealing device body (1), a heat conduction gap (4) is left between the heating rod (3) and the annealing device body (1), an air inlet (5) is provided at the upper end of the heat conduction gap (4), a fan (6) is connected between the lower end of the heat conduction gap (4) and the lower end of the annealing channel (2), and the hot air inside the heat conduction gap (4) pushes the copper-palladium alloy single crystal bonding wire in the annealing channel (2) upward from bottom to top through the fan (6).

4. The method for manufacturing a copper-palladium alloy single crystal bonding wire according to claim 3, characterized in that: A driving interlayer is provided inside the annealing device body (1), a driving layer (7) is provided inside the driving interlayer, the annealing channel (2) is located on the inner wall of the driving interlayer, and the copper-palladium alloy single crystal bonding wire in the annealing channel (2) is in contact with the driving layer (7); The annealing device body (1) is provided with a driving motor (8), the output shaft of the driving motor (8) is connected to a driving roller (9), and the driving roller (9) is in contact with the circumferential surface of the driving interlayer.

5. The method for manufacturing a copper-palladium alloy single crystal bonding wire according to claim 3, characterized in that: The annealing device body (1) comprises a preheating section (10) and a heating section (11); the heating section (11) is connected to the top of the preheating section (10); the distance between the annealing channel (2) of the preheating section (10) and the heating rod (3) gradually decreases from bottom to top; and the distance between the annealing channel (2) of the heating section (11) and the heating rod (3) is uniform and constant.

6. The method for manufacturing a copper-palladium alloy single crystal bonding wire according to claim 3, characterized in that: A heating chamber is provided in the axial direction of the annealing device body (1), and the heating rod (3) is located in the heating chamber.

7. The method for manufacturing a copper-palladium alloy single crystal bonding wire according to claim 5, characterized in that: A connecting section is provided at the lower end of the preheating section (10), and the connecting section and the heating section (11) are both cylindrical.

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