TWI600030B - Bonding wire and wire bonding method - Google Patents

Description

Bonding wire and wire bonding method [Cross-Reference to Related Applications]

The present application claims the benefit of the Korean Patent Application No. 10-2015-0008759 filed on Jan. 19, 2015 in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.

One or more exemplary embodiments are related to a bonding wire and a bonding method thereof, and more particularly, to an excellent high humidity reliability and improved spherical shape uniformity and when formed in the atmosphere. A shape of a bonding wire formed on a tip end of a wire when a free air ball (FAB) and a bonding method thereof.

Packages for mounting semiconductor devices include various types of structures. Bond wires are still widely used to connect substrates to semiconductor devices or to connect semiconductor devices. Gold bonding wires have been widely used as bonding wires. However, since gold is an expensive material and its price has recently soared, there is a need for a bonding wire that can replace gold bonding wires. Copper wire, which has been highlighted as an alternative to gold wire, has the following disadvantages: frequent A crack phenomenon in which a wafer is broken during ball bonding due to the inherent high hardness of copper occurs, and a stitch-on-bump (SOB) requiring a highly integrated package is not solved due to high hardness and strong oxidation of copper. ) Joint problem. As a solution to this drawback, research has been actively conducted on a bonding wire containing silver (Ag) as a main component and being relatively inexpensive. Although efforts have been made to develop a bonding wire which exhibits superior properties by alloying silver with other metal elements, there is still a large amount of room for improvement.

One or more exemplary embodiments include a bonding wire having excellent high humidity reliability and improved spherical shape uniformity and a shape formed on the end of the wire when forming an airless solder ball (FAB) in the atmosphere.

One or more exemplary embodiments include a bonding method of a bonding wire having excellent high humidity reliability and improved spherical shape uniformity and a shape formed on the end of the wire when forming an airless solder ball in the atmosphere.

Other aspects will be set forth in part in the description which follows.

According to one or more exemplary embodiments, a bonding wire includes a wire core containing silver (Ag) as a main component and containing a substance selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), and osmium (Os). At least one of gold (Au) and nickel (Ni); and a coating of gold (Au) material formed on the outer surface of the core.

The coating may have a thickness of from about 30 nm to about 200 nm.

The coating may have a thickness of from about 40 nanometers to about 170 nanometers.

The purity of the gold (Au) may be equal to or greater than 99%.

When an airless solder ball is formed at the end of the bonding wire in the atmosphere, the gold (Au) content on the outer surface of the airless solder ball may be about 5 wt% to 35 wt%.

According to one or more exemplary embodiments, a wire bonding method includes: preparing a bonding wire; forming an airless solder ball at an end of the bonding wire in the atmosphere; and attaching the airless solder ball to the semiconductor wafer a solder pad, wherein the bonding wire comprises: a wire core containing silver (Ag) as a main component and containing a substance selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), osmium (Os), gold (Au) And at least one element of nickel (Ni); and a coating of a gold (Au) material formed on an outer surface of the core.

The coating may have a thickness of from about 30 nm to about 200 nm.

The coating may have a thickness of from about 40 nanometers to about 170 nanometers.

The gold (Au) content on the outer surface of the airless solder ball may be from about 5 wt% to 35 wt%.

The coating can be formed by plating.

100‧‧‧bonding line

120‧‧‧Internal core

140‧‧‧Coating

A-A‧‧‧ line

S200, S210, S220, S230, S240, S250, S300, S400‧‧‧ operation

The above and/or other aspects will become more apparent and more readily understood from the following description of the exemplary embodiments in the accompanying drawings in which: FIG. 1 is a perspective view of a bonding wire in accordance with an exemplary embodiment. .

Figure 2 is a cross-sectional view taken along line A-A of the bonding wire shown in Figure 1.

3A and 3B are block diagrams of a method of manufacturing a bonding wire, according to an exemplary embodiment.

4A to 4C show scanning electron microscope (SEM) images of Comparative Example 1 and Comparative Example 2 and Experimental Example 10 in Table 1, respectively.

5A and 5B sequentially illustrate energy dispersive X-ray (EDX) analysis images of Comparative Example 2 and Experimental Example 10 in Table 1.

6A to 6D respectively illustrate images before and after the vulcanization test of Comparative Example 2 and Experimental Example 10 in Table 1.

7A and 7B sequentially show images of the sagging phenomenon of the gold coating in Experimental Example 20 and Experimental Example 24 in Table 1.

Exemplary embodiments of the inventive concept are explained in detail with reference to the accompanying drawings. However, the present invention is not limited thereto, and it is to be understood that various changes in form and details may be made without departing from the spirit and scope of the invention. That is, the description of a particular structure or function may be presented only to illustrate an exemplary embodiment of the inventive concept. The same reference numerals are used throughout the drawings to refer to the same elements. In addition, various elements and regions in the drawings are schematically illustrated. Therefore, the inventive concept is not limited to the relative dimensions or spacing shown in the drawings. In the following exemplary embodiments, the unit "wt% (% by weight)" indicates the weight of a component in the total weight of the alloy.

In the present description, terms such as "first" and "second" are used to describe various constituent elements, but the constituent elements are not limited to the terms. This term is only used to distinguish between the various constituent elements. For example, a first constituent element may be referred to as a second constituent element, and vice versa, without departing from the proper scope of the inventive concept.

The words used in the specification are for the purpose of illustrating the particular embodiments of the embodiments Therefore, the expression in the singular form also includes the plural form of expression in this specification unless the context clearly dictates otherwise. In addition, terms such as "comprises" or "comprises" or "comprising" or "an" The possibility of the presence or addition of operations, constituent elements, or a combination thereof.

Unless otherwise defined, all terms (including technical or scientific terms) used herein have the same meaning meaning meanings Terms (such as terms defined in commonly used dictionaries) are considered to have meanings that match meanings in the context of the related art, and are not considered to be ideal or too formal unless clearly defined otherwise.

The present invention discloses a silver alloy bonding wire containing silver (Ag) as a main component and containing a very small amount of other components. The main component indicates that the concentration of the element to the total component exceeds 50%. In other words, silver (Ag) as a main component indicates that the concentration of silver to the total amount of silver and other elements exceeds 50%. The concentration represents the concentration based on the mole number of the atom.

FIG. 1 is a perspective view of a bonding wire according to an exemplary embodiment. Figure 2 is a cross-sectional view taken along line A-A of the bonding wire shown in Figure 1.

As shown in FIGS. 1 and 2, the bonding wire 100 may include an inner core 120 and an outer coating 140 (or simply a coating 140). The inner core 120 has a cylindrical rod shape with a constant diameter and is made of an alloy containing silver as a main component.

The outer coating 140 has a tube shape with a constant thickness annular cross section and surrounding the outer surface of the inner core 120, and is formed of high purity gold (Au) exceeding about 99%.

In this way, since the bonding wire 100 has a structure in which the silver alloy is surrounded by high-purity gold, the bonding wire 100 can maintain the same hardness with respect to the outer surface of the wire bonding in the prior art in which the bonding wire is formed using only gold. strength. Therefore, the gold-like bonding wire is manufactured, even when an impact is applied to the semiconductor wafer pad and the substrate during the bonding process, the process can be performed without causing damage to the semiconductor wafer pad and the substrate, and can be made of high-purity gold. The shape of the surrounding silver alloy prevents oxidation of the silver alloy. Further, the bonding wire 100 according to an exemplary embodiment of the present invention and having a structure in which a silver alloy is surrounded by high-purity gold may be similar to an existing bonding wire formed only of gold to maintain, for example, corrosion resistance, ductility, elasticity, and conductivity. And other superior properties.

Further, since the bonding wire 100 according to an exemplary embodiment of the present invention has a structure in which only the outer side of the alloy is coated with high-purity gold, the manufacturing cost can be significantly reduced as compared with the existing bonding wire formed only of gold.

However, although the bonding wire according to the prior art prevents oxidation by including only a core formed of a silver alloy or a gold core formed of a silver alloy, there is a problem that only nitrogen is used therein. Or a nitrogen atmosphere of a mixed gas of nitrogen and hydrogen to produce an airless solder ball (FAB) to bond the bond wires to the semiconductor wafer pads. During the airless solder ball forming process, airless solder balls are formed when the wire is melted by field emission. In the bonding wire according to the prior art, during the formation of the airless solder ball in the atmosphere, the solder ball is unstablely formed due to rapid oxidation.

Therefore, although the shape of the airless solder ball is stable in a nitrogen atmosphere in the bonding wire according to the prior art, the gas atmosphere installation also requires gas kit installation and gas consumption cost. Further, since the deformation condition depending on the gas flow rate is generated in various manners in the shape condition of the airless solder ball, it takes a lot of time and effort to apply the deformation condition to the bonding wire.

However, in the bonding wire 100 according to an exemplary embodiment of the present invention, gold is continuously applied on the outer surface of the silver alloy core, that is, the inner core 120 of the silver alloy is coated with the high-purity gold outer coating 140 to It is about 30 nm to 200 nm, especially about 40 nm to 170 nm. Therefore, the shape of the airless solder ball is stably formed into a spherical shape in an atmospheric state, and therefore, the bonding wire 100 can be easily bonded to the semiconductor wafer pad and the substrate, and can have a silver alloy bonding equal to or better than that according to the prior art. High humidity reliability of the line.

The high humidity reliability can be produced by the bonding properties of the bonding wires which vary depending on the shape of the airless solder balls and the degree of oxidation. Unlike the prior art in which the shape of the airless solder ball is formed into an unstable bonding wire in the atmosphere, the airless solder ball The optimum shape is formed when the gold outer coating 140 has the above thickness. An inter-metallic compound (IMC) is formed between the gold coating at the end of the bonding wire and bonded to the air-free solder ball-free surface of the semiconductor wafer pad to the semiconductor wafer pad to ensure high humidity Sex can be improved.

Prepare samples

FIG. 3A is a block diagram of a method of fabricating bond wire 100, in accordance with an exemplary embodiment.

Operation S200: using high-purity silver (Ag) or using silver (Ag) as a main component, about 1 wt% to 20 wt% of molten platinum (Pt), palladium (Pd), rhodium (Rh), osmium (Os), gold ( At least one of Au) and nickel (Ni) is continuously cast to produce a cast material of the alloy. The high purity silver (Ag) or alloy cast material can be processed into a first wire having a diameter of 200 microns or less by multiple steps of a continuous drawing process.

Referring to FIG. 3B in detail, in order to have a desired composition, a metal material containing silver (Ag) as a main component is melted and cast in a melting furnace, thereby producing an alloy solution of a metal material (S210). In this state, a performance control component other than silver (Ag) may be added.

Then, the alloy solution of the metal material is cooled and solidified, and then the alloy member (S220) can be obtained by forging and rolling. Next, the alloy member may first be thinned to have a diameter of about 6 mm to about 9 mm (S230).

The first tapered wire having a diameter of about 6 mm to about 9 mm is drawn and heat-treated (S240). The drawing and heat treatment process can include making the line The gradation is fine and the process of performing heat treatment on the first tapered wire. In order to make the first tapered wire thinner, the first tapered wire passes through a plurality of dice steps to reduce the cross section of the tapered wire.

The method may include a process of performing a first heat treatment when the diameter of the tapered wire is from about 0.5 mm to about 5 mm. The first heat treatment can be performed, for example, at a temperature of from about 550 ° C to about 700 ° C for about 0.5 seconds to about 5 seconds. Specifically, the first heat treatment may be performed at a temperature of about 600 ° C to about 650 ° C for about 2 seconds to about 4 seconds.

Alternatively, the method can include a process of performing a second heat treatment when the diameter of the tapered wire is from about 0.05 mm to about 0.4 mm. The second heat treatment can be performed, for example, at a temperature of from about 550 ° C to about 700 ° C for about 0.5 seconds to about 5 seconds. Specifically, the second heat treatment may be performed at a temperature of about 600 ° C to about 650 ° C for about 2 seconds to about 4 seconds.

It is understood by those of ordinary skill in the art that the diameter of the tapered wire is reduced as the tapered wire is sequentially cut a plurality of times. In other words, as the tapered wire sequentially passes through a plurality of cuts arranged to gradually reduce the hole size, the diameter of the tapered wire is reduced.

When the diameter of the tapered wire belongs to a certain range, the above heat treatment can be performed between the respective cuts. In other words, when the diameter of the tapered wire is from about 0.5 mm to about 5 mm, the first heat treatment can be performed between a certain two cuts. When the diameter of the tapered wire is from about 0.1 mm to about 0.5 mm, a second heat treatment can be performed between a certain two cuts.

Sequentially, the thinned wire is drawn until it is made through a drawing process A bond wire having a desired diameter, thereby reducing the cross-section of the wire. In this state, the reduction in the area of the bonding wire can be adjusted by about 7% to about 15% before and after the cutting. In other words, the process can be configured such that when the wire being drawn is subjected to one cutting, the bonding wire is known by comparing the cross section of the joined bonding wire with the cross section of the bonding wire before cutting. The reduction in area is reduced by about 7% to about 15%. In particular, the reduction in the area of the bond wires in the process of drawing the wire into a diameter having a range of about 50 microns or less can be adjusted from about 7% to about 15%.

When the reduction in the area of the bonding wire is too high, the distribution of particles in the bonding wire may excessively increase. Further, when the reduction in the area of the bonding wires is too low, the number of drawing processes for obtaining the bonding wires having the desired diameter may excessively increase, which may be economically disadvantageous.

Alternatively, additional annealing may be performed after the drawing is completed to adjust the elongation (S250). The annealing conditions for adjusting the elongation may vary depending on the composition of the tapered wire, the reduction in area, or the heat treatment conditions. However, the annealing may be performed at a temperature of about 400 ° C to about 600 ° C for about 1 second to about 20 minutes. Those skilled in the art can appropriately select detailed annealing conditions.

When the annealing temperature is too low, the ductility and ductility required for bonding may not be ensured. Conversely, when the annealing temperature is too high, the size of the particles may excessively increase and defects such as a sag of the loop may be generated during bonding.

In addition, when the annealing time is too short, the ductility and malleability required for processing may not be ensured. Conversely, when the annealing time is too long, the size of the particles can be excessive. Increase, this is economically disadvantageous.

The above annealing process can be performed, for example, by passing the bonding wires through the furnace at an appropriate speed. Further, the time for passing the bonding wire through the furnace can be determined according to the annealing time and the size of the furnace.

Operation S300: A second wire can be made by forming a gold layer to a certain thickness around the first wire as shown in Table 1. The method of forming a gold layer can be performed by electrolytic plating, electroless plating, or sputtering. When the gold layer is formed by plating, the pH of the plating solution can be set to about 5 (weak acid) to about 7 (neutral) during the plating process, and the temperature of the plating solution can be maintained at about 50 ° C. Further, the boundary diffusion of the core is prevented, and the throwing power can be improved by adding one of titanium (TI), selenium (Se), and germanium (Ge) which are inorganic additives.

Operation S400: performing an electrolytic cleaning and activation process on the second wire as a pretreatment. After each process, water washing and blowing can be performed. After performing pre-processing on the second wire, the bonding wires as shown in Table 1 are completed.

2. Test method

While the structure and the effects of the present invention are described in detail in the following description of the preferred embodiments and the experimental examples, the examples of the present invention are intended to clearly illustrate the inventive concept and are not intended to limit the scope of the inventive concept. In the comparative examples and experimental examples, the physical properties were evaluated by the following methods.

(1) Ball shape uniformity

The end of the bonding wire 100 having a diameter of about 20 μm was formed into a bonding ball having a diameter of about 42 μm and bonded to the semiconductor wafer pad. In this state, measurement The ratio of the length in the lateral direction to the length in the longitudinal direction, and observing whether the ratio is close to 1, whether the bonding wire 100 is located at the center of the ball, whether the edge of the ball is as smooth as a perfect circle, or Whether there is a curved portion such as a petal shape.

When it is determined that the ratio of the length in the lateral direction of the joined ball to the length in the longitudinal direction is equal to or greater than 0.99, the bonding wire 100 is located at the center of the ball, and the edge is a perfect circle instead of a petal shape, the ball shape is uniform Sex was evaluated as ◎. When it is determined that the ratio of the length in the lateral direction of the joined ball to the length in the longitudinal direction is equal to or greater than 0.96 and less than 0.99, the bonding wire 100 is located at the center of the ball, and the edge is a perfect circle instead of a petal shape, The ball shape uniformity was evaluated as ○. When it is determined that the ratio of the length of the transverse direction of the joined ball to the length in the longitudinal direction is equal to or greater than 0.9, the edge does not have a petal shape, and the spherical shape uniformity does not belong to ◎ or ○, the spherical shape uniformity is evaluated as Δ . Otherwise, the ball shape uniformity is evaluated as ×.

(2) Stability of the gold coating

After the bonding wire 100 according to an exemplary embodiment of the present invention is fabricated, an airless solder ball is formed on the end of the bonding wire, and then the external coating existing in the airless solder ball is analyzed by energy dispersive X-ray (EDX). Gold in the layer. The formation of the airless solder balls was checked for stability based on the gold content in the outer coating of the airless solder balls. During the energy dispersive X-ray analysis, when the weight % of gold according to the gold content in the outer coating layer was more than 9 and equal to or less than 30, the stability of the gold coating was evaluated as ◎. When the weight % of gold depending on the gold content in the outer coating layer is more than 5 and equal to or less than 9, or more than 30 and equal to or less than 35, the stability of the gold coating is evaluated as Δ. When the weight % of gold based on the gold content in the outer coating is equal to or less than 3 Or greater than 35, the stability of the gold coating is evaluated as x.

(3) Vulcanization on the surface of the wire

Two samples each having 200 wire bonding and bonded to the wafer pad were fabricated, and the vulcanization phenomenon was evaluated according to the color change of the wire surface observed mainly through the microscope from above the ring. The sample was exposed to 48 hours under the worst stress conditions of room temperature, about 80% humidity, in an atmosphere containing about 3 parts per million hydrogen sulfide (H ₂ S) gas. When the number of the wire which was confirmed to be vulcanized on the surface of the wire was equal to or less than 1, the surface vulcanization was evaluated as ◎, which was excellent. When the number of wires marked as vulcanized on the surface of the wire is between 2 and 5, the surface vulcanization is evaluated as ○, which is practically acceptable. When the number of wires marked as vulcanized on the surface of the wire is between 6 and 19, the surface vulcanization is evaluated as Δ, which requires improvement. When the number of the wire which was confirmed to be vulcanized on the surface of the wire was more than 20, the surface vulcanization was evaluated as ×.

(4) High humidity reliability

Two samples each having 200 wires and bonded to the wafer pads were fabricated and packaged by sealing with an epoxy molding resin. The package was placed at a temperature of about 121 ° C and a humidity of about 85% for 96 hours, 144 hours, and 192 hours, respectively. In this state, the defect rate of the wire on which the short circuit occurred on the bonding surface was measured in percentage, and the high humidity reliability was evaluated.

3. Test results

The test results measured by the above test methods are shown in Table 1.

4A to 4C sequentially illustrate Comparative Example 1 and Comparative Example 2 in Table 1 and Scanning electron microscope image of Experimental Example 10. 5A and 5B sequentially illustrate energy dispersive X-ray analysis images of Comparative Example 2 and Experimental Example 10 in Table 1. Table 2 and Table 3 sequentially illustrate the results of energy dispersive X-ray analysis of Comparative Example 2 and Experimental Example 10.

In this test, the first line (i.e., inner core 120) has an alloy ratio in which 1% by weight of palladium (Pd) is contained and the balance is formed of silver. The test was carried out by varying the thickness of the gold in the outer coating 140 of the bond wire 100. As the thickness of the gold coating 140 increases, the data of the energy dispersive X-rays increases in proportion to the thickness.

In Comparative Example 1, air-free solder balls were formed in a nitrogen atmosphere on a bonding wire having an alloy ratio containing 1 wt% of palladium (Pd) and the balance being formed of silver and having no gold coating.

In Comparative Example 2, air-free solder balls were formed in the atmosphere on the bonding wires, The bonding wire had an alloy ratio containing 1 wt% of palladium (Pd) and the remainder was formed of silver and did not have a gold coating.

In Comparative Example 1 and Comparative Example 2 in which a gold coating layer was not formed on the silver alloy bonding wire, the airless solder ball manufactured in the nitrogen atmosphere process showed excellent spherical shape and high humidity reliability, contrary to the above case, Airless solder balls made in the atmosphere show poor ball shape and poor high humidity reliability.

In Experimental Example 1 to Experimental Example 25, air-free solder balls were formed by bonding wires having an alloy ratio of 1 wt% of palladium (Pd) and the balance of silver, and by making the thickness of the gold coating from about 2 Nano increased to 350 nm to measure data. As the thickness of the gold coating increases, the energy dispersive X-ray data increases proportionally.

In Experimental Example 1 to Experimental Example 7, it can be seen that the ball shape was unsatisfactory or acceptable compared to Comparative Example 1, and the evaluation of high humidity reliability was poor.

In Experimental Example 8, Experimental Example 17, and Experimental Example 18, the ball shape, the surface vulcanization, and the high humidity reliability were all very good, and the gold coating stability appeared to be good. Therefore, the bonding wires having the gold coating thickness in Experimental Example 8, Experimental Example 17, and Experimental Example 18 exhibited good properties.

In Experimental Example 9 to Experimental Example 16, the spherical shape, gold coating stability, wire surface vulcanization, and high humidity reliability were all very good. Therefore, the bonding wires having the gold coating thickness in Experimental Example 9 to Experimental Example 16 exhibited very good properties and were determined to be in the thickness range of the gold coating having the most excellent properties in all the tests. Further, in Experimental Example 9 to Experimental Example 16, energy dispersion The X-ray analysis results show that the gold coating has a gold content of about 5 wt% to 35 wt%.

In Experimental Example 19 to Experimental Example 25, although the spherical shape was good, the gold coating stability appeared to be unsatisfactory, and high humidity stability appeared to be poor. In other words, when the thickness of the gold coating exceeds a certain thickness, other properties than the surface of the wire are vulcanized as deterioration.

4. Based on the improvement of the thickness of the gold coating

As shown in the test results, when a gold outer coating layer 140 having a thickness of about 30 nm to 200 nm is formed on the bonding wire 100, even in the atmosphere, no air solder ball is formed in a nitrogen atmosphere. In the formation of airless solder balls, it can also be seen that the properties of the ball shape, gold coating stability, wire surface vulcanization and high humidity reliability are similar or better.

Specifically, in Experimental Example 9 to Experimental Example 16, in other words, when the thickness of the gold coating layer 140 was about 40 nm to 170 nm, all properties were excellent. When the thickness of the gold coating 140 is too thin, the spherical shape, gold coating stability, and high humidity reliability appear to be unsatisfactory. When the thickness of the gold coating 140 is too thick, gold coating stability and high humidity reliability appear to be unsatisfactory.

As shown in Figs. 6A to 6D, when the thickness of the gold coating or the gold coating is not formed too thin, it can be seen that the property of vulcanization of the wire surface appears to be unsatisfactory. 6A is a scanning electron microscope (SEM) image before the vulcanization test of Comparative Example 2, FIG. 6B is a scanning electron microscope image after the vulcanization test for Comparative Example 2, and FIG. 6C is a vulcanization test for Experimental Example 10. Previous scanning electron microscope image, and FIG. 6D is a scanning electron display after the vulcanization test of Experimental Example 10. Micromirror image.

In contrast, as shown in FIGS. 7A and 7B, when the thickness of the gold coating layer is too thick, an unstable phenomenon such as a vertical flow phenomenon of the gold coating layer can be generated in the airless solder ball. Therefore, the thickness of the gold coating can be formed to be equal to or less than about 200 nm. 7A and 7B are views sequentially showing images of the vertical flow phenomenon of the gold coating in Experimental Example 20 and Experimental Example 24 in Table 1.

5 Conclusion

In the case of the silver alloy bonding wire according to the prior art as in Comparative Example 1, although the formation of the airless solder ball is stable in a nitrogen atmosphere, the production of a nitrogen atmosphere causes gas kit mounting and gas consumption costs. Further, since the deformation condition depending on the gas flow rate is generated in various manners in the shape condition of the airless solder ball, it takes a lot of time and effort to apply the deformation condition to the bonding wire.

According to the inventive concept, even when an airless solder ball is formed at the end of the bonding wire in the atmosphere, properties such as a spherical shape and high humidity reliability are good, and a nitrogen atmosphere is not required, so that the manufacturing cost can be lowered. .

It is understood that the exemplary embodiments described herein are to be considered in a Descriptions of features and aspects within each exemplary embodiment are generally considered to be applicable to other similar features or aspects in other exemplary embodiments.

Although one or more exemplary embodiments have been described with reference to the drawings, it will be understood by those of ordinary skill in the art that the invention may be practiced without departing from the spirit and scope defined by the scope of the following claims Changes in form and detail.

100‧‧‧bonding line

120‧‧‧Internal core

140‧‧‧Coating

A-A‧‧‧ line

Claims (4)

A bonding wire comprising: a wire core containing silver (Ag) as a main component and containing a material selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), osmium (Os), gold (Au), and nickel (Ni) And at least one element of the material; and a coating of gold (Au) material formed on an outer surface of the core, wherein when an airless solder ball is formed at an end of the bonding wire in the atmosphere, The gold (Au) content on the outer surface of the airless solder ball is from about 5 wt% to 35 wt%. The bonding wire of claim 1, wherein the coating has a thickness of from about 30 nm to about 200 nm. The bonding wire of claim 1, wherein the coating has a thickness of from about 40 nm to about 170 nm. The bonding wire according to claim 1, wherein the purity of the gold (Au) is equal to or greater than 99%.