Bonding wire, bonding structure, bonding method and semiconductor device

Abstract

The present invention provides a bonding wire, a bonding structure, a bonding method and a semiconductor device, which relate to the field of semiconductor packaging. The bonding wire comprises a wire core and an outer covering layer wrapped around the wire core. The melting point of the outer covering layer material is lower than the melting point of the wire core material. The wire core is used for bonding and connecting with a target device, and the outer covering layer is used for wrapping the bonding connection point between the wire core and the target device after melting. Based on the technical solution of the present invention, a double connection between the bonding wire and the target device is achieved, and the connection force between the bonding wire and the solder joint is increased, thereby reducing the requirements for the wire core bonding process parameters under the premise of meeting the process requirements, thereby avoiding craters on the device surface due to large bonding process parameters and effectively reducing the risk of cold solder joints.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a bonding wire, a bonding structure, a bonding method and a semiconductor device. Background Art

[0002] Wedge Bond is a very important process in chip packaging. It is complex, difficult, and complex to control, and is prone to various quality problems. The purpose of this process is to connect the power chip to the external lead frame through bonding wires (usually aluminum wires), thereby connecting the chip to the external circuit. There are many ways to weld bonding wires, and ultrasonic welding is generally used. The principle is that under the action of ultrasonic energy and pressure, the molecules of the two materials are accelerated to diffuse and form an alloy, thereby connecting the two materials together.

[0003] Chip bonding is the process of bonding the bonding wire to the welding points on the chip surface under the action of ultrasonic energy and pressure. Due to the destructiveness of ultrasonic energy and pressure, and the thickness of the chip surface structure at the welding point is usually very thin, if the ultrasonic energy and pressure are slightly larger, it is easy to cause craters on the chip surface; if the ultrasonic energy and pressure are slightly lower, a cold weld will occur. In addition, in the bonding process, even if the ultrasonic energy and pressure of the equipment are well matched, the bonding quality cannot be fully guaranteed, because the bonding quality will also be affected by many other factors, such as whether the mold presses the welded area, whether the mold is worn, whether the splitter used for welding is dirty and worn, etc. Therefore, in the current chip bonding process, there are many cases of cold welds in the product, which seriously affects the quality and reliability of the product.

[0004] Therefore, in view of the fact that it is difficult to ensure the chip surface quality while avoiding the problem of cold solder joints in the current chip bonding process, it is urgent to improve in many aspects such as bonding raw materials and bonding process methods. Summary of the invention

[0005] In order to solve the problem that the current semiconductor bonding process cannot balance the guarantee of device surface quality and the avoidance of cold solder joints, the present invention proposes a bonding wire, a bonding structure, a bonding method and a semiconductor device.

[0006] In a first aspect, the present invention provides a bonding wire, comprising a wire core and an outer covering wrapped around the wire core, wherein the melting point of the outer covering material is lower than the melting point of the wire core material, the wire core is used for bonding to a target device, and the outer covering is used for wrapping the bonding connection point between the wire core and the target device after melting.

[0007] In one embodiment, the material of the outer coating is a tin alloy. According to this embodiment, the tin alloy has good electrical conductivity and welding performance, which fully meets the requirements.

[0008] In one embodiment, the tin alloy is SnAgCu alloy, SnAgPb alloy or SnAgBi alloy. According to this embodiment, different alloys formed by adding different metal elements based on the tin-silver alloy system have different performance advantages and meet different requirements.

[0009] In one embodiment, the tin content in the tin alloy is not less than 90%. According to this embodiment, the tin content is not less than 90%, which can effectively ensure the electrical conductivity and welding performance of the alloy.

[0010] In one embodiment, the SnAgCu alloy, the SnAgPb alloy and the SnAgBi alloy contain 93-98% tin, 1-5% silver, and 0.2-2% copper, lead or bismuth. Through this embodiment, the component ratio can ensure that the alloy meets the process quality requirements.

[0011] In one embodiment, the thickness of the outer coating is 2-5 μm. Through this embodiment, based on the size requirements of the bonding wire and the bonding wire core in the current bonding process, the requirements for welding quality can be met.

[0012] In a second aspect, the present invention provides a bonding structure, including a bonding wire and a target device, wherein a bonding connection point is formed between the end of the bonding wire and the surface of the target device, and the bonding connection point has a coating layer wrapping the bonding connection point.

[0013] In one embodiment, the cladding layer is formed by melting an outer cladding layer wrapped around the bonding wire core and accumulating and solidifying at the bonding connection point. According to this embodiment, the cladding layer can be formed by adding a step of heating to melt the outer cladding layer in the bonding process without any additional bonding or welding operations.

[0014] In a third aspect, the present invention provides a bonding method, comprising:

[0015] Bonding a bonding wire to a solder joint on a target device so that a core of the bonding wire is connected to the target device and a bonding connection point is formed;

[0016] Heating the bonding connection point portion to melt the outer coating on the bonding wire that wraps the wire core, and causing the fluid formed by the melting of the outer coating to accumulate at the bonding connection point;

[0017] The bonding connection point is cooled, and the fluid accumulated at the bonding connection point forms a coating layer wrapping the bonding connection point after cooling.

[0018] In one embodiment, bonding the bonding wire to the solder joint on the target device includes: causing the bonding wire under pressure to rub at the solder joint of the target device, destroying the portion of the outer covering wrapped outside the bonding wire core that contacts the target device, so as to expose the bonding wire core and connect the core to the target device. According to this embodiment, by first destroying the outer covering, the outer covering is prevented from affecting the connection between the core and the current device.

[0019] In one embodiment, before heating the bonding connection point, the method further includes: determining a target heating temperature based on the material of the core of the bonding wire and the outer covering wrapped outside the core, wherein the target heating temperature satisfies the requirement of being lower than the melting point of the core material but not lower than the melting point of the outer covering material. Through this embodiment, a suitable heating temperature is determined without affecting the structure of the core while ensuring that the outer covering is fully melted.

[0020] In one embodiment, the method further includes: bonding all solder joints on the target device to the bonding wires respectively; and heating the target device and the bonding wires connected thereto as a whole. In this embodiment, all solder joints are first bonded with bonding wires, and then heated as a whole, which can effectively improve efficiency.

[0021] In a fourth aspect, the present invention provides a semiconductor device, which utilizes the above-mentioned bonding wire for bonding packaging; and / or the semiconductor device includes the above-mentioned bonding structure, thereby having all the technical effects possessed by it.

[0022] The above technical features can be combined in various suitable ways or replaced by equivalent technical features as long as the purpose of the present invention can be achieved.

[0023] The bonding wire, bonding structure, bonding method and semiconductor device provided by the present invention have at least the following beneficial effects compared with the prior art:

[0024] A bonding wire, bonding structure, bonding method and semiconductor device of the present invention can achieve dual connection between the bonding wire and the target device through the wire core and the outer covering layer, increase the connection force between the bonding wire and the solder joint, and further reduce the requirements for the wire core bonding process parameters while meeting the process requirements, thereby avoiding craters on the device surface due to large bonding process parameters and effectively reducing the risk of cold solder joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0026] Figure 1 A schematic diagram showing the principle of the current bonding process;

[0027] Figure 2 A schematic diagram showing the structure of the bonding wire according to the present invention after preliminary bonding;

[0028] Figure 3 A schematic diagram of the bonding structure of the bonding wire according to the present invention after bonding is completed is shown;

[0029] Figure 4 A schematic diagram of the structure of the prior art after preliminary bonding is shown;

[0030] Figure 5 The figure shows a schematic diagram of the bonding structure after the bonding is completed in the prior art.

[0031] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0032] Reference numerals:

[0033] 1-bonding wire, 11-wire core, 12-outer covering layer, 13-cladding layer, 2-target device, 3-wedge. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] Example 1

[0036] An embodiment of the present invention provides a bonding wire, including a wire core 11 and an outer covering layer 12 wrapped around the wire core 11, the melting point of the material of the outer covering layer 12 is lower than the melting point of the material of the wire core 11, the wire core 11 is used for bonding to a target device 2, and the outer covering layer 12 is used for wrapping the bonding connection point between the wire core 11 and the target device 2 after melting.

[0037] Specifically, as shown in the attached figure Figure 2 As shown, the bonding wire 1 in this embodiment is a double-layer structure, including an inner core 11 and an outer covering layer 12, both of which are made of metal materials. The core 11 is used to bond with the target device 2 to achieve physical connection and conduction, while the outer covering layer 12 is mainly used to enhance the reliability of the connection structure between the core 11 and the target device 2, specifically to avoid the occurrence of cold solder joints.

[0038] Based on the bonding wire 1 of this embodiment, the principle of bonding is as follows: first, a certain pressure is applied to the bonding wire 1 by using the wedge 3 to perform preliminary bonding between the bonding wire 1 and the target device 2 (for example, ultrasonic bonding is used), that is, the wire core 11 of the bonding wire 1 is bonded to the solder joint of the target device 2, as shown in FIG. Figure 2As shown, in order to avoid damaging the target device 2 and ensure the surface quality of the target device 2, the bonding pressure and force (ultrasonic energy) will not be too large, and it is possible or easy to have a cold solder joint. Therefore, after the initial bonding, the bonding point between the wire core 11 and the target device 2 is heated (baked) to melt the outer coating 12 that partially wraps the wire core 11 at the corresponding bonding point (based on the melting point setting, the wire core 11 will not melt). The fluid formed after the outer coating 12 melts flows to the bonding interface between the wire core 11 and the target device 2 under the action of gravity (due to the bonding forming corners and a certain degree of pits) and accumulates there, which fully contacts and wraps the part of the wire core 11 and the target device 2 corresponding to the bonding point, and after cooling and solidification, forms a coating layer 13 with a certain strength, which can conduct electricity, increase the welding area at the solder joint, and can enhance the reliability of the bonding structure between the wire core 11 and the target device 2, avoiding cold solder joints of the wire core 11.

[0039] Even if a cold solder joint occurs in the wire core 11 during the initial bonding of the bonding wire 1, the conductive coating 13 formed after the outer coating 12 melts can further make up for the physical and electrical connections between the wire core 11 and the target device 2, effectively avoiding device damage caused by insufficient strength of the physical connection structure due to the cold solder joint (later desoldering) and short circuit problems caused by poor electrical connection structure.

[0040] In addition, as shown in the attached figure Figure 2 As shown, the wire core 11 of the bonding wire 1 in this embodiment is preferably set to have a circular cross-section (including a perfect circle and an ellipse). This design is mainly based on the consideration that the outer surface of the circular wire core 11 is an arc, which is convenient for the fluid formed after the outer coating 12 melts to flow spontaneously only under the action of gravity (without applying external force), and also plays a guiding role in the flow. If the wire core 11 adopts a square cross-sectional structure, then after bonding, its upper surface is basically close to the horizontal plane, which is not conducive to the spontaneous flow of the fluid formed after the outer coating 12 melts without applying other external forces; and its two side surfaces are basically close to the vertical plane, and the fluid formed after the outer coating 12 melts will flow directly vertically downward under the action of gravity, with a large impact, which can easily cause the fluid to break through the limitation of its own surface tension and flow in all directions, resulting in an unsatisfactory accumulation effect at the bonding point, and the coating 13 finally formed by cooling is insufficient in thickness and unqualified in strength.

[0041] Based on the double-layer structure of the bonding wire 1 in this embodiment, the dual connection between the bonding wire 1 and the target device 2 can be achieved through the wire core 11 and the outer covering layer 12, thereby increasing the connection force between the bonding wire 1 and the solder joint, and further reducing the requirements for the bonding process parameters of the wire core 11 under the premise of meeting the process requirements, thereby avoiding craters on the device surface due to large bonding process parameters and effectively reducing the risk of cold solder joints.

[0042] Furthermore, the material of the outer coating layer 12 is a tin alloy with a tin content of not less than 90%, and the thickness of the outer coating layer 12 is 2-5 μm.

[0043] Specifically, the main component of the tin alloy is tin, whose conductivity and melting point meet the requirements, and other components added to the alloy are mainly to optimize the temperature required for melting and the mechanical rigidity of the coating layer 13 formed after melting on the basis of tin. The thickness of the outer coating 11 mainly considers the effect on melting, the thickness of the coating layer 13 formed after melting, and the diameter of the wire core 11 of the bonding wire 1.

[0044] Among them, the outer covering layer 12 with a thickness of 2 μm is relatively small, the amount of material after melting is small, and the thickness of the formed coating layer 13 is small, which is suitable for the scene where the core 11 of the bonding wire 1 is thin and the range of bonding connection points is small; the outer covering layer 12 with a thickness of 5 μm is relatively large, the amount of material after melting is large, and the thickness of the formed coating layer 13 is large, which is suitable for the scene where the core 11 of the bonding wire 1 is thicker and the range of bonding connection points is large; for other scenes, other thicknesses such as 2.5 μm, 3 μm, and 4 μm can be adaptively selected.

[0045] Preferably, the tin alloy is SnAgCu alloy, SnAgPb alloy or SnAgBi alloy, wherein the tin content of the SnAgCu alloy, SnAgPb alloy and SnAgBi alloy is 93-98%, the silver content is 1-5%, and the remaining copper, lead or bismuth content is 0.2-2%.

[0046] Specifically, the bonding solder used in the semiconductor field currently generally adopts a tin-silver alloy system, and the further addition of metal elements is mainly based on actual performance requirements, cost and other factors. For example, the shear strength of SnAgBi alloy welding is generally greater than that of SnAgCu alloy, but the cost of SnAgBi alloy is higher.

[0047] Furthermore, the percentage content of each component in the tin alloy is mainly considered in terms of melting temperature and mechanical properties. Taking SnAgCu alloy as an example, the melting temperature and mechanical properties of the alloy are more affected by the silver and copper content. After experiments, it was found that SnAgCu alloy with a tin content of 93-98%, a silver content of 1-5%, and a copper content of 0.2-2% can basically meet the requirements.

[0048] Example 2

[0049] This embodiment mainly further optimizes the composition of the alloy. For the rest of the content, please refer to Embodiment 1, which will not be described in detail in this embodiment.

[0050] The SnAgCu alloy (or SnAgPb alloy, SnAgBi alloy) in this embodiment has a silver content of 3.0-3.1%, a copper content of 0.5-1.5%, and the remainder is tin.

[0051] Specifically, considering that the mechanical properties need to be improved as much as possible while meeting the melting temperature, further experimental results show that a tin-silver-copper alloy containing 0.5-1.5% Cu and 3.0-3.1% Ag has quite good physical and mechanical properties.

[0052] Example 3

[0053] This embodiment mainly further optimizes the composition of the alloy. For the rest of the contents, please refer to the above embodiments, which will not be described in detail in this embodiment.

[0054] The SnAgCu alloy (or SnAgPb alloy, SnAgBi alloy) in this embodiment has a tin content of 96.5%, a silver content of 3%, and a copper content of 0.5%.

[0055] Specifically, since the outer coating of the bonding wire of the present invention needs to flow by itself under the action of gravity after melting when it is used, it is necessary to consider the effect of viscosity on fluidity (copper has greater viscosity). Combined with the cost impact of each component of the alloy, the tin content in the SnAgCu alloy is determined to be 96.5%, the silver content is 3%, and the copper content is 0.5%.

[0056] Example 4

[0057] An embodiment of the present invention provides a bonding structure, including a bonding wire 1 and a target device 2, wherein a bonding connection point is formed between the end of the bonding wire 1 and the surface of the target device 2, and a coating layer 13 wrapping the bonding connection point is provided at the bonding connection point.

[0058] Specifically, as shown in the attached figure Figure 3 As shown, the bonding structure of this embodiment is mainly at the bonding connection point between the bonding wire 1 and the target device 2, specifically, the bonding part between the two is surrounded by a coating layer 13. The main function of the coating layer 13 is to enhance the reliability of the connection part between the bonding wire 1 and the target device 2. It can prevent the problem of cold solder joints in the connection part between the bonding wire 1 and the target device 2 without applying too high bonding pressure and bonding strength to the bonding wire 1 to avoid damaging the device and ensure the surface quality of the device. Figure 4 and Figure 5 The bonding wire 1 is directly bonded to the target device 2, and there is no additional reinforcement structure around the bonding point, which is prone to problems such as cold soldering, short circuit or desoldering.

[0059] In principle, the coating layer 13 can be constructed by any possible means, such as being constructed during the bonding process of the bonding wire 1, or performing an additional construction process. For example, in the simplest way, an additional welding process can be performed to inject solder into the connection portion between the original bonding wire 1 and the target device 2, and the coating layer 13 is formed after solidification.

[0060] Furthermore, the cladding layer 13 is formed by the outer cladding layer 12 wrapped around the core 11 of the bonding wire 1 being melted and then accumulated and solidified at the bonding connection point.

[0061] Specifically, in this embodiment, it is preferred to use the bonding wire 1 based on the above-mentioned embodiment to form a bonding structure, that is, a bonding wire 1 with an inner and outer two-layer structure is used, and the wire core 11 of the bonding wire 1 is bonded to the target device 2. After the bonding of the wire core 11 is completed, the bonding connection point is heated, and the outer coating 12 wrapped around the wire core 11 is melted by the heat. The fluid formed after melting (liquid or molten state, preferably heated to liquid state) flows to the corners of the bonding connection point between the wire core 11 and the target device 2 and a certain degree of pits formed by the bonding, and accumulates there (due to the effect of surface tension, it will not flow around), and the cooled fluid forms a coating layer 13 wrapped around the bonding connection point, achieving the technical effect of preventing cold solder joints.

[0062] Example 5

[0063] An embodiment of the present invention provides a bonding method, comprising:

[0064] S000: placing the bonding wire at a solder joint of a bonding wire target device;

[0065] Specifically, the splitter transports the bonding wire to a set height at the solder joint of the target device and then starts to decelerate and move downward. When the speed reaches the set speed, it moves downward at a constant speed until it is detected that the splitter has reached the solder joint surface of the target device.

[0066] S100: causing the bonding wire in a compressed state to rub at a solder joint of a target device, thereby destroying a portion of an outer covering wrapped around a core of the bonding wire that contacts the target device, so as to expose the core of the bonding wire and connect the core to the target device to form a bonding connection point;

[0067] Specifically, taking ultrasonic bonding as an example, a splitter is used to apply pressure to the bonding wire and transmit ultrasonic energy, so that the bonding wire performs high-frequency friction movement at the solder joint of the target device. This can destroy the outer covering wrapped around the wire core and squeeze the damaged outer covering part out of the welding area (so that the outer covering does not affect the connection between the wire core and the solder joint of the target device). This can expose the core of the bonding wire and make the wire core contact with the target device. Then, under the action of pressure and ultrasonic energy, after a certain period of time, the bonding wire and the solder joint of the current device are connected as a whole, completing the initial bonding in the bonding process.

[0068] In addition, when other bonding methods are used, if the outer coating cannot be effectively destroyed or squeezed out, the outer coating outside the corresponding part of the wire core can be removed in advance based on the bonding-related parameters for the part where the bonding wire needs to be bonded to expose the wire core. This method is also applicable to ultrasonic bonding.

[0069] S200: Determine a target heating temperature according to the material of the wire core and the outer covering layer wrapped outside the wire core, the target heating temperature satisfies the requirement of being lower than the melting point of the wire core material but not lower than the melting point of the outer covering layer material (also lower than the melting point of the structure at the current device solder joint), heat the bonding connection point portion in a high temperature box at the target heating temperature, melt the outer covering layer wrapping the wire core on the bonding wire, and accumulate the fluid formed after the outer covering layer melts at the bonding connection point;

[0070] S300: Cooling the bonding connection point portion, wherein the fluid accumulated at the bonding connection point is cooled to form a coating layer that wraps the bonding connection point.

[0071] Specifically, natural cooling or other active cooling methods can be used. In order to avoid the influence of too fast cooling on the coating layer structure, natural cooling is preferably used. Figure 3 .

[0072] Example 6

[0073] The embodiment of the present invention provides a bonding method. Some of the same contents refer to Embodiment 5, which will not be described in detail in this embodiment. The bonding method of this embodiment includes:

[0074] S100: causing the bonding wire in a compressed state to rub at a solder joint of a target device, thereby destroying a portion of an outer covering wrapped around a core of the bonding wire that contacts the target device, so as to expose the core of the bonding wire and connect the core to the target device to form a bonding connection point;

[0075] S200a: bonding all solder joints on the target device with bonding wires respectively;

[0076] Specifically, after the current solder joint is bonded, the bonding wire moves along the track set by the device under the action of the wedge, forming a specific wire arc to route toward the next solder joint, and then the next solder joint is bonded. The shape of the wire arc and the trajectory of the wire arc can be switched and adjusted through the parameters of the device.

[0077] S200: determining a target heating temperature according to the material of the wire core and the outer covering layer wrapped outside the wire core, wherein the target heating temperature satisfies the requirement of being lower than the melting point of the wire core material but not lower than the melting point of the outer covering layer material, heating the target device and the bonding wire connected thereto as a whole at the target heating temperature, so that the outer covering layer wrapping the wire core on the bonding wire is melted, and a fluid formed after the outer covering layer is melted is accumulated at the bonding connection point;

[0078] S300: Cooling the bonding connection point portion, wherein the fluid accumulated at the bonding connection point is cooled to form a coating layer that wraps the bonding connection point.

[0079] Example 7

[0080] An embodiment of the present invention provides a semiconductor device which is bonded and packaged using the bonding wire of the aforementioned embodiment; and / or includes the bonding structure of the aforementioned embodiment, and thus has all the technical effects of the corresponding bonding wire and the corresponding bonding structure.

[0081] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0082] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A bonding wire, characterized in that: It comprises a wire core and an outer covering layer wrapped around the wire core, wherein the melting point of the outer covering layer material is lower than the melting point of the wire core material, the wire core is used to bond to the target device and form a bonding connection point, and the outer covering layer is used to wrap the bonding connection point between the wire core and the target device after melting; wherein the thickness of the outer covering layer is 2-5μm.

2. The bonding wire according to claim 1, characterized in that The material of the outer coating layer is tin alloy.

3. The bonding wire according to claim 2, characterized in that The tin alloy is SnAgCu alloy, SnAgPb alloy or SnAgBi alloy.

4. The bonding wire according to claim 2 or 3, characterized in that: The tin content in the tin alloy is not less than 90%.

5. The bonding wire according to claim 3, characterized in that: The SnAgCu alloy, the SnAgPb alloy and the SnAgBi alloy contain 93-98% tin, 1-5% silver, and 0.2-2% copper, lead or bismuth.

6. A bonding structure, characterized in that: It comprises a bonding wire and a target device, wherein a bonding connection point is formed between the end of the bonding wire core and the surface of the target device, and a coating layer wrapping the bonding connection point is provided at the bonding connection point.

7. The bonding structure according to claim 6, characterized in that: The cladding layer is formed by melting an outer cladding layer wrapped around the bonding wire core and then accumulating and solidifying at the bonding connection point.

8. A bonding method, characterized in that: include: Bonding a bonding wire to a solder joint on a target device so that a core of the bonding wire is connected to the target device and a bonding connection point is formed; Heating the bonding connection point portion to melt the outer coating on the bonding wire that wraps the wire core, and causing the fluid formed by the melting of the outer coating to accumulate at the bonding connection point; Cooling the bonding connection point portion, wherein the fluid accumulated at the bonding connection point forms a coating layer wrapping the bonding connection point after cooling; The step of bonding the bonding wire to the solder joint on the target device includes: The bonding wire in a compressed state is caused to move frictionally at the solder joint of the target device, thereby destroying the portion of the outer covering wrapped outside the bonding wire core that contacts the target device, so as to expose the bonding wire core and connect the core to the target device.

9. The bonding method according to claim 8, characterized in that: Before heating the bonding connection point portion, the method further comprises: A target heating temperature is determined according to the core of the bonding wire and the material of the outer covering wrapped outside the core, and the target heating temperature satisfies that it is lower than the melting point of the core material but not lower than the melting point of the outer covering material.

10. The bonding method according to any one of claims 8 to 9, characterized in that: Also includes: Making all solder joints on the target device bonded to the bonding wires respectively; The target device and the bonding wire connected thereto are heated as a whole.

11. A semiconductor device, characterized in that: It uses the bonding wire according to any one of claims 1 to 5 for bonding packaging; and / or it includes the bonding structure according to claim 6 or 7.

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