KR20160135154A - Silver alloy bonding wire and manufacturing method thereof - Google Patents

Abstract

According to an embodiment of the present invention, a silver (Ag) alloy bonding wire comprises: about 1 to 20 wt% of a first additive element; about 3 to 100 weight ppm of a second additive element; and the remainder of silver (Ag). The first additive element is gold (Au), palladium (Pd), or an alloy thereof. The second additive element is at least one selected from a group of calcium (Ca), lanthanum (La), beryllium (Be), germanium (Ge), nickel (Ni), bismuth (Bi), yttrium (Y), manganese (Mn), tin (Sn), titanium (Ti), iron (Fe), copper (Cu), and magnesium (Mg). Elongation percentage is about 15 to 25%. Youngs modulus is about 60 to 80 GPa.

Description

Silver alloy bonding wire and manufacturing method < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver (Ag) alloy bonding wire and a method of manufacturing the same, and more specifically to a silver alloy bonding wire excellent in bonding characteristics and a method of manufacturing the same.

BACKGROUND ART [0002] Packages for mounting semiconductor devices have various structures. Bonding wires are used to connect a substrate to a semiconductor device or connect between semiconductor devices. Although gold (Au) bonding wires have been widely used as bonding wires, there has been a demand for bonding wires that can replace them because they are expensive and recent prices have risen sharply.

In the case of a bonding wire mainly composed of Cu, which has been spotlighted as a substitute for gold, a pad crack phenomenon frequently occurs in a chip due to high hardness of copper due to wire bonding, and SOB (stitch-on-bump) bonding has not been solved due to the high hardness and strong oxidizability of the copper.

As an alternative to this, studies on bonding wires mainly composed of silver (Ag) have been actively conducted. Efforts are being made to develop a bonding wire of superior quality by alloying silver and other metal elements, but there is still room for improvement.

A problem to be solved by the technical idea of the present invention is to provide a silver (Ag) alloy bonding wire having improved bonding properties by changing mechanical properties such as elongation at the manufacturing process step.

The problems to be solved by the technical idea of the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

A silver (Ag) alloy bonding wire according to an embodiment of the present invention includes a first additive element of about 1 to 20 wt%; About 3 to about 100 ppm by weight of a second additive element; Wherein the first additive element is gold (Au), palladium (Pd) or an alloy thereof, and the second additive element is at least one element selected from the group consisting of calcium (Ca), lanthanum (La), beryllium (Ti), Fe (Fe), copper (Cu), and magnesium (Bi), germanium (Ge), nickel (Ni), bismuth (Bi), yttrium (Y), manganese (Mg), an elongation of about 15 to 25%, and a Young's modulus of about 60 to 80 GPa.

In exemplary embodiments, the elongation is characterized by about 18 to 22%.

In the exemplary embodiments, the Young's modulus is characterized by about 65 to 80 GPa.

In exemplary embodiments, when forming the pre-air ball (FAB) at the tip of the silver-bonding wire, the cross-section hardness of the pre-air ball is about 50 to 80 Hv.

In exemplary embodiments, after bonding the silver alloy bonding wire to the bonding pad, the cross-section hardness of the bonded portion is about 80 to 120 Hv.

In the exemplary embodiments, the pad cracking phenomenon is substantially the same when the pre-air ball is formed in the atmosphere at the tip of the silver alloy bonding wire and when the pre-air ball is formed in the gas atmosphere.

A method of manufacturing a silver alloy bonding wire according to an embodiment of the present invention includes: a first additive element of about 1 to 20 wt%; About 3 to about 100 ppm by weight of a second additive element; Wherein the first additive element is gold (Au), palladium (Pd) or an alloy thereof, and the second additive element is at least one element selected from the group consisting of calcium (Ca), lanthanum (La), beryllium (Ti), Fe (Fe), copper (Cu), and magnesium (Bi), germanium (Ge), nickel (Ni), bismuth (Bi), yttrium (Y), manganese (Mg); < / RTI > And annealing the first wire at about 500 to 700 占 폚 in an atmosphere of nitrogen to have an elongation of about 15 to 25% and a Young's modulus of about 60 to 80 GPa.

In exemplary embodiments, the elongation is characterized by about 18 to 22%.

In the exemplary embodiments, the Young's modulus is characterized by about 65 to 80 GPa.

The silver alloy bonding wire according to the present invention uses a silver (Ag) alloy to save manufacturing cost and can have excellent bonding properties.

Further, the silver alloy bonding wire according to the present invention can have a high bonding property with the semiconductor element pad by improving the bonding property by changing the mechanical properties such as elongation, and thus can have high product reliability.

1A and 1B are sectional views of a pre-air ball formed at the tip of a silver (Ag) alloy bonding wire.
2A and 2B are block diagrams illustrating a method of manufacturing a silver alloy bonding wire according to an embodiment of the present invention.
FIGS. 3A and 3B are a side view and a plan view illustrating a bonding state of a silver alloy bonding wire according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the inventive concept may be modified into various other forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the inventive concept are desirably interpreted to provide a more complete understanding of the inventive concept to those skilled in the art. The same reference numerals denote the same elements at all times. Further, various elements and regions in the drawings are schematically drawn. Accordingly, the inventive concept is not limited by the relative size or spacing depicted in the accompanying drawings. In the embodiments of the present invention, wt% (% by weight) is a percentage of the weight of the total alloy in weight of the total alloy.

The terms first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and conversely, the second component may be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the expressions "comprising" or "having ", etc. are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, It is to be understood that the invention does not preclude the presence or addition of one or more other features, integers, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs, including technical terms and scientific terms. In addition, commonly used, predefined terms are to be interpreted as having a meaning consistent with what they mean in the context of the relevant art, and unless otherwise expressly defined, have an overly formal meaning It will be understood that it will not be interpreted.

In the present invention, in order to prevent the pad crack when the pre-air ball is formed in the atmosphere by obtaining loop characteristics and ball shape uniformity at the gold bonding wire level, the mechanical properties such as elongation ratio are changed in the manufacturing process step, A silver alloy bonding wire having a high bonding strength with the element pad is provided.

The Young's modulus is increased in proportion to the elongation of the bonding wire and the tilting of the pre-air ball is not generated as the straightness of the bonding wire is improved after the stitch bonding by the elasticity, so that the uniformity of the bonded ball shape can be improved .

The process of forming the free air ball (FAB) at the tip of the wire for testing the bonding characteristics with the silver alloy bonding wire according to the embodiment of the present invention can be carried out in a gas atmosphere and in air .

In the case of the silver alloy bonding wire, the inside of the FAB formed in the gas atmosphere is as shown in FIG. 1A. Alternatively, a wire part as shown in FIG. 1B may remain inside the FAB formed in the atmosphere. The FAB thus formed has a high hardness due to the wire part and can cause a crack in the semiconductor pad during wire bonding.

In order to solve this problem, the grain size of the alloy constituting the wire is increased as the elongation of the silver alloy bonding wire is increased. As a result, the hardness of the wire part remaining in the FAB is reduced by 30% or more.

Therefore, in the case of the silver alloy bonding wire according to the embodiment of the present invention, cracking of the semiconductor pad can be reduced even if the FAB is formed in the air and bonded to the pad.

In this specification, the gas atmosphere means a nitrogen (N ₂ ) gas atmosphere or a gas atmosphere in which nitrogen (N ₂ ) is mixed with about 1 to 10% of hydrogen (H ₂ ). In the present specification, the atmosphere means a general atmospheric state, not a gas atmosphere.

Generally, the shape of the FAB is stable in the gas atmosphere, but the gas kit installation and the gas consumption cost are additionally generated in order to make the gas atmosphere. In addition, the deforming conditions vary depending on the gas flow rate in the shape condition of the FAB, and it takes much time and effort to apply it to the bonding wire.

1. Sample Preparation

According to an embodiment of the present invention, there is disclosed a silver alloy bonding wire containing about 80 to 99% by weight of silver (Ag) and further comprising an additive element. Silver (Ag) has the highest electrical conductivity among metals, for example, has electrical conductivity higher than that of gold by about 30% or more. In addition, since silver is cheaper than gold, it can contribute to material cost reduction. In addition, since silver (Ag) has mechanical properties similar to gold, the conventional gold wire bonding process can be applied as it is.

According to an embodiment of the present invention, the bonding wire may further include gold (Au), and the amount of gold may be about 1% to 20% by weight with respect to the entire bonding wire. If the content of gold is too small, the shape of the ball formed at the tip of the bonding wire may be excessively deviated from the true sphere, and the bonding property may deteriorate. On the contrary, if the content of gold is too large, the hardness of the ball formed at the tip of the wire at the time of wire bonding may excessively increase, and the bonding pad and / or the substrate below it may be damaged.

According to an embodiment of the present invention, the bonding wire may further include palladium (Pd), wherein the content of the palladium may be about 1% by weight to about 20% by weight with respect to the entire bonding wire. If the content of palladium is too small, the acid resistance is deteriorated and can easily be corroded or short-circuited by nitric acid, sulfuric acid or the like. In particular, if palladium is not contained, oxidation resistance of the silver alloy bonding wire may become weak. On the contrary, if the content of palladium is excessively high, the hardness of the ball formed at the tip of the wire at the time of wire bonding excessively increases, and the bonding pad and / or the substrate below it may be damaged.

According to an embodiment of the present invention, the bonding wire may include gold (Au) and palladium (Pd) at the same time, and the content of the gold and palladium may be about 1 to 20% % ≪ / RTI > If the content ratio of gold to palladium is too low, the shape of the ball formed at the tip of the bonding wire may deviate from the true sphere and the bonding characteristics may deteriorate. Further, there is a problem that the surface of the bonding wire is easily oxidized and discolored. On the other hand, if the content ratio is too high, the true configuration of the ball formed at the tip of the bonding wire deteriorates. In addition, the hardness of the ball formed at the tip of the bonding wire may excessively rise, possibly damaging the bonding pad and / or the substrate thereunder.

According to an embodiment of the present invention, the bonding wire may be formed of at least one selected from the group consisting of Ca, lanthanum, beryllium, germanium, nickel, bismuth, yttrium, About 3 to 100 parts by weight per 100 parts by weight of at least one member selected from the group consisting of Mn, Sn, Ti, Fe, Cu and Mg. The calcium (Ca), lanthanum (La), and yttrium (Y) can homogenize the microstructure, but it is not effective at less than about 3 ppm by weight, and when added in an amount exceeding about 100 ppm by weight, Can be imported. The tin (Sn), iron (Fe), copper (Cu), and magnesium (Mg) can improve the workability of the bonding wire. However, when the content is less than about 3 ppm by weight, And segregation may occur. The beryllium (Be), nickel (Ni), and titanium (Ti) can improve the reliability of the bonding wire, but are less effective at less than about 3 ppm by weight and increase in hardness And precipitates may occur on the surface of the alloy. The bismuth (Bi), manganese (Mn) and germanium (Ge) can improve the ball shape uniformity, but less than about 3 ppm by weight is not effective and more than about 100 ppm by weight causes segregation in the alloy .

According to one embodiment of the present invention, if the elongation and Young's modulus are too small, bonding properties such as loop characteristics, ball shape uniformity and pad cracking are poor. On the other hand, if the elongation and Young's modulus are too large, it may be impossible to manufacture with a bonding wire.

According to an embodiment of the present invention, if the cross-sectional hardness of the FAB and the cross-sectional hardness of the bonding ball are too large, the bonding characteristics such as loop characteristics, ball shape uniformity and pad cracking are not good. On the other hand, if the section hardness of the FAB and the section hardness of the bonding ball are too small, wire bonding may not be possible.

2. Manufacturing Method

2A is a block diagram illustrating a method of manufacturing a silver alloy bonding wire according to an embodiment of the present invention.

Step S100: an alloyed material can be manufactured by using silver of high purity or by dissolving and continuously casting gold and palladium (Pd) to about 1 to 20 wt% with silver as a main component. A high purity silver or alloyed material can be processed into a wire having a diameter of about 200 mu m or less through a continuous drawing process of several stages.

Referring to FIG. 2B, a metal raw material containing silver as a main component may be dissolved and cast in a melting furnace to have a desired composition (S110). At this time, components other than silver can be added.

Then, an alloy piece can be obtained by forging, rolling, or the like by cooling and solidifying the total amount of the metal raw material (S120). Next, the alloy piece may be thinned by a wire having a diameter of about 6 mm to 9 mm (S130).

Alternatively, the sum of the metal raw materials may be thinned by continuous casting with a wire having a diameter of about 6 mm to 9 mm (S115).

The thinned wire is drawn and heat-treated to have a diameter of about 6 mm to 9 mm (S140). In the drawing and heat treatment step, the wire may be progressively thinned and heat-treated. And the cross-sectional area of the wire can be reduced by passing a multi-step die to form the wire.

And performing a primary heat treatment when the diameter of the wire is about 0.5 mm to 5 mm. The primary heat treatment may be performed at, for example, about 550 ° C to 700 ° C for about 0.5 seconds to 5 seconds. More preferably, the primary heat treatment can be performed at about 600 DEG C to 650 DEG C for about 2 seconds to 4 seconds.

Alternatively, the method may further include performing a secondary heat treatment when the diameter of the wire is about 0.05 mm to 0.5 mm. The secondary heat treatment may be performed at, for example, about 550 ° C to 700 ° C for about 0.5 seconds to 5 seconds. More preferably, the secondary heat treatment can be performed at about 600 ° C to 650 ° C for about 2 seconds to 4 seconds.

One of ordinary skill in the art will appreciate that the diameter decreases as the wire sequentially passes through a number of dice. In other words, the wire decreases in diameter while sequentially passing through a plurality of dice arranged so that the size of the hole gradually decreases.

The above heat treatments can be performed between any dice and dice when the diameter of the wire falls within that range. In other words, the primary heat treatment can be performed between any two dice when the diameter of the wire is about 0.5 mm to 5 mm. The secondary heat treatment may be performed between any two dice when the diameter of the wire is about 0.05 mm to 0.5 mm.

The wire is then drawn until the desired diameter of wire is produced through the drawing process, thereby reducing the cross-section of the wire. At this time, the cross-sectional reduction rate of the wire before and after the die can be adjusted to about 7% to 15%. That is, the process can be configured such that when the wire in drawing passes through one die, the cross-sectional area after passing is reduced by about 7% to 15% compared to the cross-sectional area before passing. Particularly, in the step of drawing to a diameter of about 50 탆 or less, it is preferable that the cross-sectional reduction rate of the wire is adjusted to about 7% to 15%.

If the cross-sectional reduction rate of the wire is too high, the dispersion of the crystal grains in the wire may become excessively large. In addition, if the reduction rate of the cross-section of the wire is too low, the number of drawing processes required to obtain the wire of the desired diameter becomes too large and economically disadvantageous.

In order to control the elongation, annealing may be performed after the drawing is completed (S150). The annealing conditions for controlling the elongation can be varied depending on the composition of the wire, the reduction ratio, the heat treatment conditions and the like, but can be performed at a temperature of about 500 ° C to 700 ° C for about 1 second to 20 minutes.

If the annealing temperature is too low, the required ductility and electrical conductivity may not be secured at the time of wire bonding. On the contrary, if the annealing temperature is too high, the crystal grain size may excessively increase and defects such as deflection of the loop may occur .

The above annealing process can be performed, for example, by passing the wire through a furnace at a proper speed. Further, the rate at which the wire passes through the furnace can be determined from the annealing time and the size of the furnace.

In the comparative examples and the embodiments of the present invention, the thinned wire is annealed at a temperature of about 400 to 850 ° C in a nitrogen (N ₂ ) atmosphere, and the process is performed to have different elongation ratios.

In order to produce a bonding wire having an elongation of about 5 to 10%, it is preferable to set the annealing temperature to about 400 to 500 DEG C, and in order to produce a bonding wire having an elongation of about 11 to 15% The annealing temperature is preferably 600 to 850 DEG C in order to produce a bonding wire having an elongation of about 16 to 25%.

Step S200: The wire is subjected to electrolytic degreasing or activation treatment by a pretreatment, and water washing and air blowing can be performed after each step. After the wire is subjected to a pretreatment process, silver alloy bonding wires of various comparative examples and examples as shown in Tables 1 and 2 below are completed.

3. Test method

(1) Wire bonding

3A is a side view for explaining a stitch-on-bump (SOB) bonding to a bump in more detail, and FIG. 3B is a plan view of a portion B in FIG. 3A, a first bonding pad 10 and a second bonding pad 20 to be electrically connected are provided, and a bump 30 is provided on the second bonding pad 20 do. The bump 30 may be a ball bump or a stud bump. Here, the stud bump will be described.

A bump 30 is provided on the second bonding pad 20 of the provided bonding pads 10 and 20. The method of providing such a bump 30 is well known to those skilled in the art, do.

The silver alloy bonding wire 100 is bonded to the bump 30 on the second bonding pad 20 after ball bonding is performed on the first bonding pad 10 forming a ball at the tip of the alloy bonding wire 100 And stitch bonding is performed on the bumps 30.

Referring to FIG. 3B, in the stitch-bonded form, it is preferable that the left and right shapes and sizes are substantially symmetrical with respect to the center line C as a center. When the uniform bonding force is applied to the entire bonding wire width at the time of stitch bonding, if the properties of the bonding wire are substantially uniform with respect to the entire width, the shape and size of the left and right sides of the stitch bonding surface centered on the center line C are substantially symmetrical .

In order to further improve the bonding characteristics of the silver alloy bonding wire 100, mechanical characteristics such as elongation can be varied through an annealing process. Young's modulus changes according to the variation of the elongation ratio. As a result, the bonding property is improved and a crack is generated in the bonding pads 10 and 20.

(2) Ball shape uniformity

A bonding wire having a diameter of about 20 mu m is bonded to a pad so as to be a bonding ball having a diameter of about 42 mu m, and the ratio of the length in the horizontal axis direction to the length in the vertical axis direction is measured. , Whether the edges were smooth in a circular shape, or whether there was a petal-like curvature.

When the ratio of the length of the bonded ball to the length of the horizontal axis direction and the length of the longitudinal axis direction is 0.99 or more and the bonding wire is located at the center of the ball and the edge is judged to be a circle without a petal shape, Is 0.96 or more and less than 0.99 and the bonding wire is located at the center of the ball and the edge is judged to be a circle without a petal shape, the ratio of the length of the bonded ball in the horizontal axis direction to the longitudinal axis direction is 0.9 or more, And when it is not applicable to the above ⊚ or ◯, it is evaluated as △, otherwise, it is evaluated as ×.

(3) Loop characteristics

Bumps were formed on one of the two rows of bonding pads arranged at intervals of about 3000 mu m to form bumps. Then, ball bonding was performed on the opposite side, and stitch bonding was performed on the bumps while forming a loop.

Then, the interval is measured for the narrowest interval between the loops, and this is determined as a value representative of the interval between the loops. Through this process, the linearity of the loop can be evaluated.

When the interval between the loops thus determined was 111 mu m to 125 mu m, & cir &, 105 mu m or more and less than 111 mu m were rated O and 105 mu m, respectively.

(4) pad crack

Bumps were formed on one of the bonding pads to form a bump, and after the ball bonding was removed, it was confirmed whether or not a crack was present in the pad.

A total of 100 pads were analyzed. When no pad cracks were generated at all, ⊚; when 1 to 5 pad cracks occurred, ◯; when pad cracks were 6 to 10, Δ; and 11 or more pad cracks occurred , The evaluation was evaluated as " X ".

4. Test results

(1) Analysis of results

In order to evaluate the mechanical properties of the comparative example and the example, Vickers Hardness Vickers (Hv) was measured using an HM2000 instrument manufactured by Fisher, and the application time was 10 seconds, the crepp time was 5 seconds And a load of 20 mN was applied.

In order to evaluate the bonding characteristics of the comparative example and the example, the process of forming the FAB at the tip of the silver alloy bonding wire proceeded in a gas atmosphere and in the atmosphere, respectively. Table 1 shows the results obtained when FAB was formed in the gas atmosphere on the bonding wire having the same composition ratio, and Table 2 shows the results when the FAB was formed in the atmosphere.

(2-A) Comparative Examples 1A and 2A

When the silver alloy bonding wire having a silver content of less than about 80 wt% is produced so as to have an elongation of about 22%, the Young's modulus has a value between about 73 and 78 GPa. When FAB is formed in a gas atmosphere, it is understood that the loop characteristic and the ball shape uniformity are very good, but the pad crack is normal. That is, even though the mechanical property ranges such as elongation and Young's modulus were adjusted to the same numerical range as that of Examples of the present invention through Comparative Examples 1A and 2A, when the silver content was low (less than about 80 wt%), It can be judged that the bonding property of the substrate is not good.

(2-B) Comparative Examples 1B and 2B

When the silver alloy bonding wire having a silver content of less than about 80 wt% is produced so as to have an elongation of about 22%, the Young's modulus has a value between about 73 and 78 GPa. When the FAB is formed in the atmosphere, it is understood that the loop characteristic and the ball shape uniformity are very good, but the pad crack is defective. That is, even if the mechanical properties such as elongation and Young's modulus are adjusted to the same numerical range as in the embodiments of the present invention through Comparative Examples 1B and 2B, when the silver content is low (less than about 80 wt%), It can be judged that the bonding property of the substrate is not good.

(3-A) Comparative Examples 3A to 5A

About 8 wt% of gold, about 2 wt% of palladium, about 10 wt% of calcium, about 50 wt ppm of copper, about 5 wt ppm of beryllium and about 15 wt ppm of geranium, Experiments were conducted while varying the elongation of the alloy bonding wire from about 8 to 14%. As the elongation increases, the Young's modulus increases from about 51 to 54 GPa in proportion thereto, and the section hardness of the FAB and the section hardness of the bonding ball decrease.

In the case of forming the FAB in the gas atmosphere, in Comparative Example 3A, the loop characteristic is normal, the ball shape uniformity is poor, and the pad crack is normal. In Comparative Example 4A, it is found that the loop characteristic is normal, the ball shape uniformity is poor, and the pad crack is good. In Comparative Example 5A, it is found that the loop characteristic and the ball shape uniformity are normal and the pad crack is very good. That is, it can be seen that as the elongation increases from about 8 to 14%, the Young's modulus increases and the bonding property also moves. However, it can be judged that the bonding characteristic can not be confirmed.

(3-B) Comparative Examples 3B to 5B

About 8 wt% of gold, about 2 wt% of palladium, about 10 wt% of calcium, about 50 wt ppm of copper, about 5 ppm of beryllium and about 15 ppm of zeolite, Experiments were conducted while varying the elongation of the alloy bonding wire from about 8 to 14%. As the elongation increases, the Young's modulus increases from about 51 to 54 GPa in proportion thereto, and the section hardness of the FAB and the section hardness of the bonding ball decrease.

In the case of forming the FAB in the atmosphere, in the comparative example 3B, the loop characteristics are normal, the ball shape uniformity is poor, and the pad crack is defective. In Comparative Example 4B, it is found that the loop characteristic is normal, the ball shape uniformity is poor, and the pad crack is defective. In Comparative Example 5B, it can be seen that loop characteristics, ball shape uniformity, and pad cracks are all normal. That is, it can be seen that as the elongation increases from about 8 to 14%, the Young's modulus increases and the bonding property also moves. However, it can be judged that the bonding characteristic can not be confirmed.

(4) Comparative Examples 6A and 6B

As for Comparative Examples 6A and 6B, it is impossible to measure the mechanical properties and the bonding properties of the silver alloy bonding wire having an elongation of about 28% or more.

(5-A) Example 1A

Compared with Comparative Examples 1A and 2A, when the content of silver is set to about 80 wt% and the elongation is made about 22%, the Young's modulus becomes about 76 GPa. It can be seen that when the FAB is formed in a gas atmosphere, the loop characteristics and the ball shape uniformity are very good and the pad crack is good. That is, it can be seen that the silver alloy bonding wire having a silver content of about 80 wt% or more has better bonding properties than a silver alloy bonding wire having a silver content of less than about 80 wt%.

(5-B) Example 1B

Compared with Comparative Examples 1B and 2B, when the content of silver is set to about 80 wt% and the elongation is made to be about 22%, the Young's modulus becomes about 76 GPa. When FAB is formed in the atmosphere, it is found that the loop characteristic and the ball shape uniformity are very good and the pad crack is good. That is, it can be seen that the silver alloy bonding wire having a silver content of about 80 wt% or more has better bonding properties than a silver alloy bonding wire having a silver content of less than about 80 wt%.

(6-A) Examples 2A and 3A

In comparison with the comparative examples 3A to 5A, the silver content was about 90 wt%, the gold content was about 8 wt%, the palladium content was about 2 wt%, calcium was about 10 wt ppm, copper was about 50 wt ppm, beryllium was about 5 wt ppm, The experiment was conducted while varying the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 15 to less than 18%. As the elongation increases, the Young's modulus increases proportionally and the FHS cross-section hardness and the cross-section hardness of the bonding ball decrease.

In the case of forming the FAB in the gas atmosphere, it was found that the loop characteristic and the ball shape uniformity were good and the pad crack was very good in Example 2A. It can be seen from Example 3A that the loop characteristic is very good, the ball shape uniformity is good, and the pad crack is very good.

That is, in the case of the silver alloy bonding wire having an elongation of about 15% or more, all the bonding characteristics are considered to be at a satisfactory level because they have bonding characteristics falling within the range of defects that may occur in the manufacturing process,

(6-B) Examples 2B and 3B

In comparison with the comparative examples 3B to 5B, it is preferable that the silver content is about 90 wt%, the gold content is about 8 wt%, the palladium content is about 2 wt%, calcium is about 10 wtppm, copper is about 50 wtppm, beryllium is about 5 wtppm, The experiment was conducted while varying the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 15 to less than 18%. As the elongation increases, the Young's modulus increases proportionally and the FHS cross-section hardness and the cross-section hardness of the bonding ball decrease.

In the case of forming the FAB in the atmosphere, the loop characteristic and the ball shape uniformity are good and the pad crack is very good in Example 2B. It can be seen that in Example 3B, the loop characteristic is very good, the ball shape uniformity is good, and the pad crack is very good.

That is, in the case of the silver alloy bonding wire having an elongation of about 15% or more, all the bonding characteristics are considered to be at a satisfactory level because they have bonding characteristics falling within the range of defects that may occur in the manufacturing process,

(7-A) Examples 4A to 6A

It is judged to be the mechanical characteristic range showing the most preferable result among the embodiments of the present invention.

In comparison with the comparative examples 3A to 5A, the silver content was about 90 wt%, the gold content was about 8 wt%, the palladium content was about 2 wt%, calcium was about 10 wt ppm, copper was about 50 wt ppm, beryllium was about 5 wt ppm, The experiment was carried out while varying the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 18 to 22%. As the elongation increases, the Young's modulus increases from about 73 to 76 GPa, the FAB cross-section hardness decreases from about 58 to 55 Hv, and the cross-section hardness of the bonding ball decreases from about 94 to 93 Hv.

In the case of forming the FAB in a gas atmosphere, it can be seen that loop characteristics, ball shape uniformity and pad cracks are very good in all of Examples 4A to 6A. That is, it is determined that the elongation period exhibits the most preferable bonding characteristics.

(7-B) Examples 4B to 6B

It is judged to be the mechanical characteristic range showing the most preferable result among the embodiments of the present invention.

In comparison with the comparative examples 3B to 5B, it is preferable that the silver content is about 90 wt%, the gold content is about 8 wt%, the palladium content is about 2 wt%, calcium is about 10 wtppm, copper is about 50 wtppm, beryllium is about 5 wtppm, The experiment was carried out while varying the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 18 to 22%. As the elongation increases, the Young's modulus increases from about 73 to 76 GPa in proportion to the increase in elongation, and the cross-sectional hardness of the FAB decreases from about 63 to 60 Hv, and the bonding hardness of the bonding ball ranges from about 101 to 100 Hv.

In the case of forming the FAB in the atmosphere, the loop characteristics, the ball shape uniformity, and the pad crack are very good in all of Examples 4B to 6B. That is, it is determined that the elongation period exhibits the most preferable bonding characteristics.

(8-A) Examples 7A and 8A

In comparison with the comparative examples 3A to 6A, the silver content was about 90 wt%, the gold content was about 8 wt%, the palladium content was about 2 wt%, calcium was about 10 wtppm, copper was about 50 wtppm, beryllium was about 5 wtppm, The experiment was carried out while changing the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 23.5 to 25%. As the elongation increases, the Young's modulus increases proportionally and the FHS cross-section hardness and the cross-section hardness of the bonding ball decrease.

In the case of forming the FAB in the gas atmosphere, in Examples 7A and 8A, the loop characteristics are very good, the ball shape uniformity is good, and the pad crack is very good. That is, in the case of a silver alloy bonding wire having an elongation of more than about 22% and not more than 25%, all of the bonding properties are considered to be at a satisfactory level because they have bonding characteristics that fall within the range of defects that may occur during the manufacturing process.

(8-B) Examples 7B and 8B

In comparison with the comparative examples 3B to 6B, it is preferable that the silver content is about 90 wt%, the gold content is about 8 wt%, the palladium content is about 2 wt%, calcium is about 10 wtppm, copper is about 50 wtppm, beryllium is about 5 wtppm, The experiment was carried out while changing the elongation of the silver alloy bonding wire having the composition ratio of 15 ppm by weight from about 23.5 to 25%. As the elongation increases, the Young's modulus increases proportionally and the FHS cross-section hardness and the cross-section hardness of the bonding ball decrease.

In the case of forming the FAB in the atmosphere, in Examples 7B and 8B, the loop characteristics are very good, the ball shape uniformity is good, and the pad crack is very good. That is, in the case of a silver alloy bonding wire having an elongation of more than about 22% and not more than 25%, all of the bonding properties are considered to be at a satisfactory level because they have bonding properties that fall within the range of defects that may occur during the manufacturing process.

5. Conclusion

The silver alloy bonding wire according to the embodiment of the present invention can be manufactured by a method in which a silver bonding wire having a mechanical range of a certain range by varying mechanical values such as an alloy composition, an elongation, a Young's modulus and a section hardness of a bonding wire, To form wire bonding with the semiconductor element pads, the semiconductor element pads can have excellent bonding properties with the semiconductor element pads and thus can have high product reliability.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The present invention may be modified in various ways. Therefore, modifications of the embodiments of the present invention will not depart from the scope of the present invention.

The present invention can be usefully used in the semiconductor industry.

10: First side bonding pad
20: Second side bonding pad
30: Bump
100: silver alloy bonding wire

Claims (5)

1 to 20% by weight of a first additive element;
3 to 100 parts by weight of a second additive element; And
The remaining silver (Ag)
Wherein the first additive element is gold (Au), palladium (Pd) or an alloy thereof,
The second additive element may be at least one selected from the group consisting of Ca, lanthanum, beryllium, germanium, nickel, bismuth, yttrium, manganese, tin ), Titanium (Ti), iron (Fe), copper (Cu), and magnesium (Mg)
An elongation of 15 to 25%
A silver alloy bonding wire having a Young's modulus of 60 to 80 GPa,
Wherein the pre-air ball has a section hardness of 50 to 80 Hv when the pre-air ball (FAB) is formed at the tip of the silver-silver bonding wire. The method according to claim 1,
And an elongation of 18 to 22%. The method according to claim 1,
And a Young's modulus of 65 to 80 GPa. The method according to claim 1,
After the silver alloy bonding wire is bonded to the bonding pad,
Wherein the bonded portion has a section hardness of 80 to 120 Hv. The method according to any one of claims 1 to 4,
Wherein the silver alloy bonding wire has substantially the same crack cracking phenomenon when the pre-air ball is formed in the atmosphere at the tip of the silver alloy bonding wire and when the pre-air ball is formed in the gas atmosphere.

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