Novel chip bonding wire and preparation method thereof

Abstract

The copper bonding wire is low in price, and along with the improvement of the copper bonding wire technology, the copper bonding wire gradually tends to replace a gold bonding wire. However, due to the preparation process and characteristics of the material, certain defects exist in use, and a large space is still optimized at present. According to the method provided by the invention, the mother alloy needs to be inserted into the bottom of the glass tube and heated, and the microwire is pulled out from the bottom of the softened glass tube through the traction effect, so that the amorphous composite wire is obtained. And breaking and stripping the glass coating layer of the prepared amorphous composite filament to obtain the amorphous core. And finally, cutting the amorphous core to a required length according to requirements to obtain the bonding wire. The generated bonding wire is low in price, the manufacturing raw materials are easy to purchase, the cost can be greatly reduced, the diameter is extremely small, electronic element miniaturization is facilitated, mutual contact between flat cables is effectively prevented, short circuit is avoided, and the condition of the high-quality bonding wire is met.

Description

Technical Field

[0001] The present application relates to the technical field of a novel chip bonding wire. Background Art

[0002] The semiconductor industry and LED industry are large in scale and developing rapidly. Their miniaturization and integration trends have led to a rapid increase in demand for ultra-fine bonding wires for chip bonding.

[0003] As a product family, bonding wire is one of the key materials for semiconductor packaging. Its function is to realize the electrical connection between semiconductor chips and pins, and plays the role of current import and export between chips and the outside world. At present, it is mainly composed of gold wire, which accounts for more than 80% of the total share. Because of its soft quality, corrosion resistance and good electrical properties, it is widely used as bonding wire. However, with the continuous rise in international gold prices, the price of gold bonding wire has also risen all the way, resulting in excessively high costs for terminal products, which is not conducive to improving the competitiveness of enterprises. In recent years, the continuous rise in gold prices has promoted the development of gold wire substitutes, including copper wire, other alloy wires, etc. Among them, copper wire has been relatively mature and has begun to be used.

[0004] Copper bonding wire is cheap, and with the improvement of copper bonding wire technology, it is gradually replacing gold bonding wire. However, due to the preparation process and characteristics of the material, there are certain defects in its use, and there is still a lot of room for optimization.

[0005] At present, the traditional drawing method is usually used to prepare bonding wires, that is, first heat and melt the metal rod, and then draw it through dies of different diameters to reduce the diameter of the wire. This method is relatively complicated, especially for preparing wires with a diameter of less than 15m, and the number of wire drawing is large. Due to the limitations of the process method, there is little room for further size reduction. Moreover, as the size of the bonding wire decreases, its manufacturing cost will increase significantly.

[0006] Therefore, it is necessary to invent a new method for chip bonding wire. Summary of the invention

[0007] Traditionally, the drawing method is usually used to prepare metal bonding wires, which is not only complicated in process but also increases production costs. The present invention first inserts the master alloy into the bottom of a glass tube and heats it, and then pulls out microwires from the bottom of the softened glass tube through a pulling action to obtain an amorphous composite wire prototype containing a glass coating layer and an amorphous core, and then rapidly cools the amorphous composite wire prototype to obtain an amorphous composite wire.

[0008] By means of physical rolling, the glass coating layer is broken and separated from the amorphous core. The amorphous core is wound on a wire collection roller for collection. The amorphous core is then cut into a desired length to obtain the novel chip bonding wire.

[0009] According to the method proposed in the present invention, the chip bonding wire produced does not contain a glass coating layer. The produced bonding wire is inexpensive, the raw materials are easy to purchase, the diameter is extremely fine, which is conducive to the miniaturization of electronic components, and it can effectively prevent the wiring from contacting each other to avoid short circuits. At the same time, it has good conductivity and meets the requirements of high-quality bonding wire.

[0010] Therefore, the present invention includes the following embodiments:

[0011] Embodiment 1. A method for preparing a chip bonding wire, characterized in that it comprises the following steps:

[0012] Step 1: Insert the master alloy rod into the bottom of the glass tube;

[0013] Step 2: Use induction heating to melt the master alloy rod at the bottom of the glass tube to form a molten master alloy.

[0014] The molten master alloy softens the bottom of the glass tube;

[0015] Step 3: Pull out the microwire from the bottom of the softened glass tube to obtain an amorphous composite wire prototype containing a glass coating layer and an amorphous core;

[0016] Step 4: rapidly cooling the amorphous composite wire to obtain a cooled amorphous composite wire or making the temperature of the amorphous composite wire lower than the induction heating temperature of step 2;

[0017] Step 5: allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a cooled state or allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a heated state, wherein the width of the roller gap is greater than the diameter of the amorphous core and smaller than the diameter of the amorphous composite wire, so that the rolling force causes the glass cladding layer to break and separate from the amorphous core;

[0018] Step 6: Wind the amorphous core onto a wire-receiving roller, and keep the wire-receiving roller at a constant linear speed;

[0019] Step 7: Cut the amorphous core into required lengths to obtain the novel chip bonding wire.

[0020] Embodiment 2: According to the method for preparing a novel chip bonding wire described in Embodiment 1, the master alloy rod in step 1 comprises:

[0021] Cu content is greater than 95wt%;

[0022] The content of B, Nb, Cu, Mn, Mo, Ni and Al is less than 5wt%.

[0023] Embodiment 3: According to the method for preparing a novel chip bonding wire described in embodiment 1, the master alloy rod in step 1 contains Cu, and its content is 100wt%.

[0024] Embodiment 4: According to the method for preparing a novel chip bonding wire described in embodiment 1, the difference between the melting point of the master alloy and the softening temperature of the glass tube in step 1 is higher than 50°C and lower than 500°C.

[0025] Embodiment 5: According to the method for preparing a novel chip bonding wire described in Embodiment 1, the thickness of the glass coating layer described in step 3 is 0.1-20 microns.

[0026] Embodiment 6: According to the method for preparing a novel chip bonding wire described in embodiment 1, the rolling roller in step 5 is cylindrical, and the rolling roller curved surface contains one or more transverse continuous ridges, which may be rectangular, trapezoidal or triangular, or any polygonal shape.

[0027] Embodiment 7: According to the method for preparing a new chip bonding wire described in embodiment 1, the continuous passing process in step 5 is that the amorphous composite wire passes through two rolling rollers, and the two rolling rollers rotate at a uniform speed toward the side where the amorphous composite wire passes and roll the amorphous composite wire.

[0028] Embodiment 8. According to the method for preparing a novel chip bonding wire described in Embodiment 1, the linear speed of rotation of the rolling roller in step 5 is 10-100 m / min.

[0029] Embodiment 9. According to the method for preparing a novel chip bonding wire described in embodiment 1, the linear speed of the wire collection roller in step 7 is 10-100 m / min.

[0030] Embodiment 10. A chip bonding wire, characterized in that: it is prepared by the method of embodiment 1, does not contain a glass coating layer, contains a Cu content greater than 95wt%; and the content of B, Nb, Cu, Mn, Mo, Ni and Al is less than 5wt%.

[0031] Embodiment 11: A chip bonding wire, characterized in that it is prepared by the method of embodiment 1, does not contain a glass coating layer, and has a Cu content of 100wt%.

[0032] Embodiment 12: A chip bonding wire, characterized in that it is prepared by the method of embodiment 1, and has a diameter of 2-50 microns and a length of 1-8 mm.

[0033] According to the aforementioned embodiment, the method provided by the present invention requires first inserting the master alloy into the bottom of the glass tube and heating it, and then pulling out the microwires from the bottom of the softened glass tube through pulling action to obtain an amorphous composite wire prototype containing a glass coating layer and an amorphous core, and then rapidly cooling the amorphous composite wire prototype to obtain an amorphous composite wire. The amorphous core in the amorphous composite wire obtained by this method has an extremely fine diameter and is relatively soft.

[0034] Afterwards, the amorphous composite wire is rolled by a rolling roller to destroy and peel off the glass coating to obtain an amorphous core. Since there is no obstruction of the glass coating, the conductivity is enhanced. At the same time, the amorphous core obtained after removing the glass coating is softer and less likely to damage electronic components. Finally, the amorphous core is cut to the required length according to demand to obtain the bonding wire. The generated bonding wire is low in price and the raw materials are easy to purchase, which can greatly reduce costs. The extremely fine diameter is conducive to the miniaturization of electronic components, effectively preventing the wiring from contacting each other to avoid short circuits, and meeting the conditions of high-quality bonding wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0036] In the present invention:

[0037] Figure 1 : Schematic diagram of the process of preparing amorphous core of the present invention

[0038] Figure 2 : Schematic diagram of the cross section of amorphous composite wire

[0039] Figure 3 : Schematic diagram of cross section of amorphous composite wire

[0040] Figure 4 : Schematic diagram of the rolling process of the rolling roller with trapezoidal ridges

[0041] Figure 5 : Schematic diagram of the rolling process of the rolling roller with triangular ridges

[0042] In the figure: 11-feeding area, 12-glass tube, 13-master alloy rod, 14-heating area, 15-high frequency induction furnace, 16-cooling area, 17-cooling liquid, 18-amorphous composite wire, 19-wire collection roller, 20-rolling roller, 21-glass coating layer, 22-amorphous core, 23-bonding wire, 24-convex ridge. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] A method for preparing a chip bonding wire, characterized in that it comprises the following steps:

[0045] Step 1: Insert the master alloy rod into the bottom of the glass tube;

[0046] Step 2: Use induction heating to melt the master alloy rod at the bottom of the glass tube to form a molten master alloy.

[0047] The molten master alloy softens the bottom of the glass tube;

[0048] Step 3: Pull out the microwire from the bottom of the softened glass tube to obtain an amorphous composite wire prototype containing a glass coating layer and an amorphous core;

[0049] Step 4: rapidly cooling the amorphous composite wire to obtain a cooled amorphous composite wire or making the temperature of the amorphous composite wire lower than the induction heating temperature of step 2;

[0050] Step 5: allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a cooled state or allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a heated state, wherein the width of the roller gap is greater than the diameter of the amorphous core and smaller than the diameter of the amorphous composite wire, so that the rolling force causes the glass cladding layer to break and separate from the amorphous core;

[0051] Step 6: Wind the amorphous core onto a wire-receiving roller, and keep the wire-receiving roller at a constant linear speed;

[0052] Step 7: Cut the amorphous core into required lengths to obtain the novel chip bonding wire.

[0053] In some embodiments, the master alloy rod comprises:

[0054] Cu content is greater than 95wt%;

[0055] The content of B, Nb, Mn, Mo, Ni and Al is less than 5wt%.

[0056] At present, the traditional drawing method is usually used to prepare bonding wires, that is, first heat and melt the metal rod, and then draw it through dies of different diameters to reduce the diameter of the metal wire and form microwires that meet the required diameter. This method is relatively complicated, especially for the preparation of metal wires with a diameter of less than 20m. The number of wire drawing times is large, and the complex process increases the production cost, which cannot meet the existing processing needs.

[0057] The present invention provides a method for preparing a chip bonding wire, firstly, melting an alloy rod and a glass tube, generating an amorphous composite wire prototype by traction, and obtaining the amorphous composite wire after cooling. The amorphous composite wire has poor conductivity due to the presence of a glass coating layer, cannot meet the requirement of high conductivity of the bonding wire, and is not suitable as a raw material for the bonding wire. In addition, due to the high hardness of the amorphous composite wire, it is easy to scratch electronic components. Therefore, it is necessary to remove the glass coating layer of the outer layer of the amorphous composite wire.

[0058] The method provided by the present invention removes the glass coating layer by rolling, and the amorphous composite wire passes through the roller gap formed by two rolling rollers, and the rolling pressure generated by the rolling rollers breaks the glass coating layer to obtain an amorphous core. The amorphous core is cut into a required length to obtain the novel chip bonding wire.

[0059] The above method greatly shortens the process flow, reduces production costs, and can be prepared continuously. The processed microwires have good conductivity and are suitable for use as bonding wires for connecting electronic components. At the same time, they have a very thin diameter and low hardness, and are not easy to damage electronic components. This is conducive to the miniaturization of electronic chips and can be widely used in electronic chip products.

[0060] In some embodiments, the master alloy rod contains Cu, and its content is 100wt%. Pure Cu bonding wire is cheaper than bonding wire containing other metals such as Au and Ag. Under the same conditions, the use of pure Cu bonding wire can greatly reduce costs. At the same time, when the wire diameter is the same, the resistivity of Cu wire is lower than that of Au wire, and it has better electrical properties. When obtaining the same conductivity, a thinner Cu wire can be used. In particular, in the packaging of precision electronic components, a thinner Cu wire can be used without affecting the electrical performance.

[0061] In some embodiments, the difference between the melting point of the master alloy and the softening temperature of the glass tube is higher than 50°C and lower than 500°C. When the difference between the melting point of the master alloy and the softening temperature of the glass tube is 50-500°C, the process flow for preparing amorphous composite wires can reach an optimal state. Glass has a low melting point and melts and softens before the master alloy. If the difference is too large, after the glass softens, the master alloy still does not melt and cannot be drawn, thereby failing to form an amorphous composite wire. When the temperature difference is too small, the entire reaction speed is too fast, difficult to control, and not conducive to industrial production.

[0062] In some embodiments, the glass coating layer has a thickness of 0.1-20 microns.

[0063] In the method provided by the present invention, the glass coating layer should not be too thick. If the coating layer is too thick, the glass coating layer will easily hang and adhere to the surface of the amorphous core after the prepared amorphous composite wire is rolled by the rolling roller and will not fall off easily, which will greatly affect the preparation effect.

[0064] In some embodiments, the rolling roller is cylindrical, and the curved surface of the rolling roller contains one or more transverse continuous ridges, which may be rectangular, trapezoidal, triangular, or any polygonal shape.

[0065] The rolling roller is set to be cylindrical, and the pressure on the amorphous composite wire is uniform when rotating, which makes it easy to make the glass coating layer fall off. One or more transverse continuous ridges are set on the surface of the rolling roller. The ridges of any shape and any number can be set. When the ridges contact the glass coating layer during rotation, the local pressure on its surface increases, which makes it easy to destroy and peel off the glass coating layer. The number and shape of the ridges can be set arbitrarily according to the needs of the product. Generally speaking, the sharper the shape of the ridges and the greater the number of ridges, the better the peeling effect. The two rolling rollers can achieve the purpose of the ridges on the two rolling rollers cooperating with each other by setting the initial position. The reasonable initial position not only makes the peeling efficiency high, but also does not easily damage the amorphous core.

[0066] In order to better remove the glass coating, multiple groups of rolling rollers can be set, and the size of the roller gap generated by them decreases. When the amorphous composite wire passes through one by one, the glass coating that was not completely removed in the previous rolling process is rolled and peeled off again. The rolling roller can have a self-cooling function to quickly cool the amorphous composite wire. Cooling and rolling are carried out simultaneously, which can save the previous cooling step and make the entire production process more efficient.

[0067] In some embodiments, the continuous passing process is that the amorphous composite wire passes through two rolling rollers, and the two rolling rollers rotate at a uniform speed toward the side where the amorphous composite wire passes and roll the amorphous composite wire.

[0068] The two rolling rollers rotate toward the side where the amorphous composite wire passes, which can maximize the pressure and facilitate wire collection. The uniform rotation has the best peeling effect, and the pressure transmission is uniform and sufficient, ensuring that the whole process is continuous and stable.

[0069] In some embodiments, the rolling roller rotates at a linear speed of 10-100 m / min.

[0070] The results of the experiment show that the peeling effect is best when the roller rotation speed is 10-100 m / min. When the speed is lower than 10 m / min, the overall silk production efficiency is too low. When the speed is higher than 100 m / min, the pressure transmission of the roller is unstable, resulting in poor removal of the glass coating.

[0071] In some embodiments, the linear speed of the wire collection roller is 10-100 m / min.

[0072] The speed of the wire collection roller should not be too fast or too slow. If it is too slow, the collection efficiency will be affected. If it is too fast, it will have a significant pulling effect on the unfinished amorphous core, which is not conducive to the entire preparation process and the aforementioned process of removing the glass coating.

[0073] In some embodiments, the chip bonding wire is characterized in that: it is prepared by the method of embodiment 1, does not contain a glass coating layer, contains a Cu content greater than 95wt%; and the content of B, Nb, Mn, Mo, Ni and Al is less than 5wt%.

[0074] The bonding wire prepared by the method for preparing bonding wire proposed in the present invention does not contain a glass coating layer, has a low hardness and an extremely fine diameter, is conducive to the miniaturization of electronic components, effectively prevents the wiring from contacting each other to avoid short circuits, and has good conductivity, making it suitable for use as a bonding wire.

[0075] In some embodiments, a chip bonding wire is characterized in that: it is prepared by the method of embodiment 1, does not contain a glass coating layer, and has a Cu content of 100 wt%.

[0076] The bonding wire prepared by the method for preparing bonding wire proposed in the present invention does not contain a glass coating layer. The generated bonding wire is made of pure copper, is inexpensive and easy to purchase, has an extremely fine diameter, is conducive to miniaturization of electronic components, effectively prevents wires from contacting each other to avoid short circuits, and has good conductivity, making it suitable for use as bonding wire.

[0077] In some embodiments, a chip bonding wire is characterized in that it is prepared by the method of embodiment 1 and has a diameter of 2-50 microns and a length of 1-8 mm.

[0078] According to the method provided in Implementation Example 1, after the amorphous core is obtained through various steps, the amorphous core is sheared according to actual needs to obtain a bonding wire that meets the length requirements.

[0079] Example

[0080] Example 1

[0081] like Figure 1 As shown, in this embodiment, firstly, a mother alloy rod 13 with a Cu content of 99wt% and an Al content of 1wt% is selected, with a melting point of 1050°C and a diameter of 1.5mm; a glass tube 12 with an operating temperature of 825°C, an outer diameter of 4mm and a wall thickness of 0.5mm is selected.

[0082] Insert the master alloy rod 13 into the bottom of the glass tube 12;

[0083] A high frequency induction furnace is used to melt the master alloy rod 13 and heat it to 1200°C;

[0084] Softening the glass tube 12 using the molten master alloy rod 13;

[0085] The wire is pulled out by drawing;

[0086] The master alloy in a molten state is cooled by a cooling zone 16 and a cooling liquid 17 to form an amorphous composite wire 18 having a diameter of 13 microns, wherein the glass coating layer is 1.5 microns;

[0087] The two rolling rollers 20 each have 12 trapezoidal ridges 24, and the roller gap 21 formed by the two rolling rollers 20 is 10 microns. The amorphous composite wire passes through the roller gap 21 and is rolled to peel off the glass coating layer to form an amorphous core 22. The linear speed of the two rolling rollers 20 is 30 meters per minute.

[0088] The amorphous core roll 22 is wound on the wire-receiving roller 19 at a wire-receiving speed of 30 m / min.

[0089] By adjusting parameters such as feeding speed and temperature, the drawing process is kept stable and continuous preparation of the amorphous core 22 is achieved.

[0090] The obtained continuous amorphous core 22 is cut into bonding wires 23 having a length of 5 mm.

[0091] The bonding wire 23 prepared in the above manner has a diameter of 10 μm. It is measured that at room temperature of 20°C, its conductivity is 55.0×10 6 S / m.

[0092] In Example 1, through the method provided by the present invention, the glass coating layer is destroyed by rolling and peeling by a rolling roller, and the bonding wire produced has an extremely small diameter, high electrical conductivity, low cost, and is more conducive to the miniaturization of electronic chips.

[0093] Comparative Example 2

[0094] like Figure 1 As shown:

[0095] In this embodiment, firstly, an Au content of 100 wt % is selected, the melting point of which is 1065° C., and the diameter is 1.5 mm; a glass tube 12 with an operating temperature of 825° C., an outer diameter of 4 mm, and a wall thickness of 0.5 mm is selected.

[0096] Insert the master alloy rod 13 into the bottom of the glass tube 12;

[0097] A high frequency induction furnace is used to melt the master alloy rod 13 and heat it to 1200°C;

[0098] Softening the glass tube 12 using the molten master alloy rod 13;

[0099] The wire is pulled out by drawing;

[0100] The master alloy in a molten state is cooled by a cooling zone 16 and a cooling liquid 17 to form an amorphous composite wire 18 having a diameter of 13 microns, wherein the glass coating layer is 1.5 microns;

[0101] The two rolling rollers 20 each have 12 trapezoidal ridges 24, and the roller gap 21 formed by the two rolling rollers 20 is 10 microns. The amorphous composite wire passes through the roller gap 21 and is rolled to peel off the glass coating layer to form an amorphous core 22. The linear speed of the two rolling rollers 20 is 30 meters per minute.

[0102] The amorphous core roll 22 is wound on the wire-receiving roller 19 at a wire-receiving speed of 30 m / min.

[0103] By adjusting parameters such as feeding speed and temperature, the drawing process is kept stable and continuous preparation of the amorphous core 22 is achieved.

[0104] The obtained continuous amorphous core 22 is cut into bonding wires 23 having a length of 5 mm.

[0105] The bonding wire 23 prepared in the above manner has a diameter of 10 μm. It is measured that at room temperature of 20°C, its conductivity is 43.0×10 6 S / m.

[0106] In Comparative Example 2, through the method provided by the present invention, the glass coating layer is destroyed by rolling and peeling by a rolling roller, and the resulting Au wire has an extremely small diameter, which is the same as the bonding wire generated in Comparative Example 1. According to the comparison with Example 1, it can be seen that the bonding wire prepared according to the present invention uses more than 95wt% copper as the main alloy material, which has better conductivity than pure gold wire and lower cost, is more conducive to the miniaturization of electronic chips, and is a better raw material for preparing bonding wire.

[0107] Comparative Example 3

[0108] like Figure 2 As shown, in this embodiment, firstly, a mother alloy rod 13 with a Cu content of 99wt% and an Al content of 1wt% is selected, with a melting point of 1050°C and a diameter of 1.5mm; a glass tube 12 with an operating temperature of 825°C, an outer diameter of 4mm and a wall thickness of 0.5mm is selected.

[0109] Insert the master alloy rod 13 into the bottom of the glass tube 12;

[0110] A high frequency induction furnace is used to melt the master alloy rod 13 and heat it to 1200°C;

[0111] Softening the glass tube 12 using the molten master alloy rod 13;

[0112] The wire is pulled out by drawing;

[0113] The master alloy in a molten state is cooled by a cooling zone 16 and a cooling liquid 17 to form an amorphous composite wire 18 having a diameter of 13 microns, wherein the glass coating layer is 1.5 microns;

[0114] The amorphous composite filament is wound on a wire-receiving roller 19 at a speed of 30 m / min.

[0115] By adjusting parameters such as feeding speed and temperature, the drawing process is kept stable and continuous preparation of amorphous composite wire is achieved.

[0116] The obtained continuous amorphous composite wire is continuously cut into bonding wires with a length of 5 mm and a glass cladding layer.

[0117] The bonding wire with glass coating prepared by the above method has a diameter of 13 microns. It is measured that its conductivity is 34×10 6 S / m.

[0118] Example 3 uses a master alloy rod with the same components as Example 1, and the factors such as the glass tube diameter, thickness, and heating temperature during the production process are completely consistent. The difference is that after the amorphous composite wire is generated, the glass coating layer is not peeled off by a rolling roller, so the bonding wire finally generated is a bonding wire with a glass coating layer. A bonding wire with a glass coating layer of the same length as Example 1 was selected and tested under the same room temperature environment. Compared with Example 1, the conductivity of the bonding wire with a glass coating layer generated in this comparative example is significantly reduced, because the non-metallic material of the glass coating layer limits the conductivity of the bonding wire.

[0119] Example 4

[0120] like Figure 1 As shown, in this embodiment, firstly, a mother alloy rod 13 with a Cu content of 100wt% is selected, with a melting point of 1084°C and a diameter of 1.5mm; and a glass tube 12 with a working temperature of 825°C, an outer diameter of 4mm and a wall thickness of 0.5mm is selected.

[0121] Insert the master alloy rod 13 into the bottom of the glass tube 12;

[0122] A high frequency induction furnace is used to melt the master alloy rod 13 and heat it to 1200°C;

[0123] Softening the glass tube 12 using the molten master alloy rod 13;

[0124] The wire is pulled out by drawing;

[0125] The obtained amorphous composite wire 18 has a diameter of 13 μm, wherein the glass coating layer is 1.5 μm;

[0126] like Figure 5 As shown, this embodiment is provided with three groups of rolling rollers 20, the first two groups of rolling rollers 20 each have 12 trapezoidal ridges 24, and the first group of rolling rollers 20 has a self-cooling function, which can quickly cool down the amorphous composite wire, and the third group of rolling rollers 20 each have 6 triangular ridges 24, the roller gap 21 formed by the first group of two rolling rollers 20 is 12 microns, the roller gap 21 formed by the second group of two rolling rollers 20 is 11 microns, and the roller gap 21 formed by the third group of two rolling rollers 20 is 10 microns, and the amorphous composite wire 18 passes through the roller gap 21 in sequence, and after rolling, the glass coating layer is peeled off to form an amorphous core 22. The linear speed of the three groups of rolling rollers 20 is 30 meters / minute.

[0127] The amorphous core roll 22 is wound on the wire-receiving roller 19 at a wire-receiving speed of 30 m / min.

[0128] By adjusting parameters such as feeding speed and temperature, the drawing process is kept stable and continuous preparation of the amorphous core 22 is achieved.

[0129] The obtained continuous amorphous core 22 is cut into bonding wires 23 with a length of 5 mm. The bonding wires 23 prepared in the above manner have a diameter of 10 μm. It is measured that the electrical conductivity is 58.5×10 6 S / m.

[0130] This embodiment sets three groups of rolling rollers, and the first group has a self-cooling function. When the amorphous composite wire with a heating temperature enters the rolling roller, the rolling roller can cool the amorphous composite wire, thus eliminating the cooling step and greatly saving time in the production process. In addition, the three groups of rolling rollers are set with different roller gaps. The roller gap of the first group is the largest, and the roller gap of each subsequent group of rolling rollers decreases in sequence. This allows the glass coating layer to be rolled and peeled off multiple times by multiple groups of rolling rollers. When the glass coating layer is not completely removed in the first peeling, the subsequent rolling process will damage the glass coating layer again, and the overall peeling effect of the glass coating layer is better.

[0131] This embodiment uses a different number and shape of ridges from the previous embodiments and comparative examples, which is intended to illustrate that any shape and any number of ridges can be used in the present invention. When the roller gap formed by the two rolling rollers is smaller than the diameter of the amorphous composite wire and larger than the diameter of the amorphous core, the rolling roller will exert a greater pressure on the glass coating on the amorphous composite wire. As the rolling roller rotates, the ridges on the rolling roller further destroy and peel off the glass coating until it is removed. So in general, the more ridges there are and the sharper the shape, the more thorough the peeling of the glass coating and the better the peeling effect. However, it should be noted that the distance of the roller gap should be set reasonably to avoid damaging the amorphous core in the amorphous composite wire. In addition, the two rolling rollers can be set to an initial position in order to achieve the effect of the ridges on the two rolling rollers cooperating with each other. A reasonable initial position not only makes the peeling efficiency high, but also does not easily damage the amorphous core.

[0132] This embodiment uses 100wt% Cu as the raw material for producing bonding wires. When the diameter and length of the bonding wires are equal and the ambient temperature is the same, the electrical conductivity is better than that of the Cu alloy in Example 1 and the pure Au wire in Comparative Example 2. It can be seen that 100wt% Cu is suitable for making bonding wires. When the method provided by the present invention is used for preparation, the bonding wire has a relatively low hardness due to its small diameter. In addition, it has the advantages of low raw material price and simple manufacturing process. The electrical conductivity of the bonding wire finally made is relatively high, which meets all the requirements of high-quality bonding wires.

[0133] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.

Claims

1. A method for preparing a chip bonding wire, characterized in that: The steps include: Step 1: Insert the master alloy rod into the bottom of the glass tube; Step 2: Use induction heating to melt the master alloy rod at the bottom of the glass tube to form a molten master alloy. The molten master alloy softens the bottom of the glass tube; Step 3: Pull out the microwire from the bottom of the softened glass tube to obtain an amorphous composite wire prototype containing a glass coating layer and an amorphous core; Step 4: rapidly cooling the amorphous composite wire to obtain a cooled amorphous composite wire or making the temperature of the amorphous composite wire lower than the induction heating temperature of step 2; Step 5: allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a cooled state or allowing the amorphous composite wire to continuously pass through a roller gap formed by a rolling roller in a heated state, wherein the width of the roller gap is greater than the diameter of the amorphous core and smaller than the diameter of the amorphous composite wire, so that the rolling force causes the glass cladding layer to break and separate from the amorphous core; Step 6: Wind the amorphous core onto a wire-receiving roller, and keep the wire-receiving roller at a constant linear speed; Step 7: Cut the amorphous core into required lengths to obtain the novel chip bonding wire.

2. The method for preparing a novel chip bonding wire according to claim 1, wherein the master alloy rod in step 1 comprises: Cu content is greater than 95wt%; One or more of B, Nb, Mn, Mo, Ni and Al, the content of which is less than 5 wt%.

3. The method for preparing a novel chip bonding wire according to claim 1, wherein the master alloy rod in step 1 contains Cu, and its content is 100wt%.

4. According to the method for preparing a novel chip bonding wire according to claim 1, in step 1, the difference between the melting point of the master alloy and the softening temperature of the glass tube is higher than 50°C and lower than 500°C.

5. According to the method for preparing a novel chip bonding wire according to claim 1, the thickness of the glass coating layer in step 3 is 0.1-20 microns.

6. According to the method for preparing a novel chip bonding wire according to claim 1, the rolling roller in step 5 is cylindrical, and the rolling roller curved surface contains one or more transverse continuous ridges, and the ridges can be rectangular, trapezoidal or triangular, or any polygonal shape.

7. According to the method for preparing a new chip bonding wire according to claim 1, the continuous passing process in step 5 is that the amorphous composite wire passes through two rolling rollers, and the two rolling rollers rotate at a uniform speed toward the side where the amorphous composite wire passes and roll the amorphous composite wire.

8. According to the method for preparing a novel chip bonding wire according to claim 1, the linear speed of rotation of the rolling roller in step 5 is 10-100 m / min.

9. According to the method for preparing a novel chip bonding wire according to claim 1, the linear speed of the wire collection roller in step 7 is 10-100 m / min.

10. A chip bonding wire, characterized in that: The method of claim 1 is used to prepare the composite material, the composite material does not contain a glass coating layer, and contains a Cu content greater than 95 wt % and a B, Nb, Mn, Mo, Ni and Al content less than 5 wt %.

11. A chip bonding wire, characterized in that: The method of claim 1 is used for preparing the composite material, but the composite material does not contain a glass coating layer and has a Cu content of 100 wt%.

12. A chip bonding wire, characterized in that: Prepared by the method of claim 1, the diameter is 2-50 microns and the length is 1-8 mm.

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