COPPER ALLOY BONDING WIRE FOR SEMICONDUCTOR DEVICES

Abstract

In a copper alloy bonding wire for semiconductor devices, the bonding longevity of a ball bonded part under high-temperature and high-humidity environments is improved. The copper alloy bonding wire for semiconductor devices includes in total 0.03% by mass or more to 3% by mass or less of at least one or more kinds of elements selected from Ni, Zn, Ga, Ge, Rh, In, Ir, and Pt (first element), with the balance Cu and inevitable impurities. The inclusion of a predetermined amount of the first element suppresses production of an intermetallic compound susceptible to corrosion under high-temperature and high-humidity environments at the wire bonding interface and improves the bonding longevity of a ball bonded part.

Claims

1. A copper alloy bonding wire for semiconductor devices, comprising: one or more kinds of first elements selected from Ni, Zn, Ga, Ge, In and Ir, wherein the total content of the first elements is 0.05% by mass or more and 3% by mass or less; and 0.0001% by mass or more and 0.050% by mass or less of each of at one or more kinds of elements selected from P and Mg, with the balance comprising Cu and inevitable impurities, and the copper alloy bonding wire is a bare Cu alloy wire.

2. A copper alloy bonding wire for semiconductor devices, comprising: one or more kinds of first elements selected from Ni, Zn, Ga, Ge, In and Ir, wherein the total content of the first elements is 0.05% by mass or more; and in total 0.03% by mass or more of one or more kinds of elements selected from Rh and Pt, and total concentration of the elements and the first elements is 3% by mass or less, with the balance comprising Cu and inevitable impurities, and the copper alloy bonding wire is a bare Cu alloy wire.

3. The copper alloy bonding wire for semiconductor devices according to claim 2, wherein the copper alloy bonding wire further comprises 0.0001% by mass or more and 0.050% by mass or less of each of one or more kinds of elements selected from Ti, B, P, Mg, Ca, La, As, Te and Se, with respect to the entire wire.

4. The copper alloy bonding wire for semiconductor devices according to any one of claims 1 to 3, wherein an average crystal grain size (m) in core cross section of the copper alloy bonding wire is $\begin{array}{cc}0.02R+0.4\mathrm{or}\mathrm{more}& \left(1a\right)\end{array}$ $\begin{array}{cc}0.1R+0.5\mathrm{or}\mathrm{less}& \left(1b\right)\end{array}$ where R (m) is a diameter of the wire and the core cross section is vertical to a wire axis of the copper alloy bonding wire.

5. The copper alloy bonding wire for semiconductor devices according to any one of claims 1 to 4, wherein an average film thickness of copper oxide on a surface of the wire is in a range of 0.0005 m or more and 0.02 m or less.

6. The copper alloy bonding wire for semiconductor devices according to any one of claims 1 to 5, wherein the copper alloy bonding wire further comprises in total 0.0005% by mass or more and 0.5% by mass or less of one or more kinds of elements selected from Ag and Au, with respect to the entire wire.

7. The copper alloy bonding wire for semiconductor devices according to any one of claims 1 to 6, wherein the copper alloy bonding wire further comprises 1.15% by mass or less of Pd.

8. The copper alloy bonding wire for semiconductor devices according to any one of claims 1 to 7, wherein the copper alloy bonding wire comprises two or more kinds of first elements selected from Ni, Zn, Ga, Ge, In and Ir.

Description

EXAMPLES

[0037] In the following, the bonding wire according to embodiments of the present invention will be specifically described with Examples.

(Samples)

[0038] First of all, the method of preparing a sample will be described. Cu having a purity of 99.99% by mass or more (in the present example, 6N (the one with a concentration of 99.9999% by mass or more was used)) with the balance inevitable impurities was used as the raw material of core. The first element, the second element, the third element, and Pd having a purity of 99% by mass or more with the balance inevitable impurities were used. In order to achieve the composition of wire or core as intended, additional elements to the core, that is, alloy elements including the first element, the second element, the third element, and Pd are prepared. Although the elements may be prepared singly, a Cu mother alloy including an additional element may be produced in advance and then prepared so as to achieve the desired amount of addition, if the element alone has a high melting point or the amount of addition is extremely small.

[0039] The copper alloy was produced by continuous casting so as to have a wire diameter of a few millimeters. The resultant alloy of a few millimeters was drawn to yield wire having a diameter of 0.3 to 1.4 mm. In the wire drawing, a commercially available lubricant was used, and the wire drawing rate was 20 to 150 m/min. Except for some examples, acid washing with hydrochloric acid or the like was performed to remove an oxide film on the wire surface. Subsequently, wire drawing was performed using dies, in which at least half of all the dies had an area reduction ratio of 10 to 21%, and in the meantime, heat treatment at 200 to 600 C. was performed once to three times, achieving a diameter of 20 m or a diameter of 18 m. After the processing, heat treatment was performed such that the final breaking elongation was about 5 to 15%. The heat treatment was performed by continuously sweeping the wire and supplying N.sub.2 or Ar gas. The wire feeding speed was 10 to 90 m/min, the heat treatment temperature was 350 to 600 C., and the heat treatment time was 1 to 10 seconds. As for the production process in Examples 6, 10, 11, 23, 55, 56, 62, and 77, the heat treatment temperature in Examples 11 and 56 was low, 300 C. or lower, and the heat treatment temperature in Examples 6, 10, 55, 62, and 77 was high, 700 C. or higher.

Method of Evaluation

[Element Content]

[0040] The alloy element contents in the wire were analyzed using an ICP optical emission spectrometer.

[Crystal Grain Size]

[0041] The crystal grain size was determined by the EBSD method. For analysis of EBSD measurement data, dedicated software (for example, OIM Analysis manufactured by TSL Solutions) was used. The crystal grain size is the arithmetic mean of equivalent diameters (the diameter of a circle equivalent to the area of the crystal grain) of crystal grains included in the measurement region.

[Average Film Thickness of Copper Oxide]

[0042] In the measurement of the average film thickness of copper oxide on the wire surface, depth analysis by Auger spectroscopy was performed, and the average value of the film thicknesses of copper oxide measured at at least three points or more at random positions on the wire surface was used. With sputtering by Ar ions, the measurement was performed in the depth direction, and the unit of the depth is that of equivalent SiO.sub.2 thickness. The oxygen concentration of 30% by mass is set as the boundary between copper oxide and metal copper. As used herein the oxygen concentration is the ratio of the oxygen concentration to the total concentration of Cu, oxygen, and metal elements. In measurement, SAM-670 (type FE manufactured by PHI Inc.) was used, and the measurement was conducted with acceleration voltage of electron beams of 5 kV, the measurement region of 10 nA, the acceleration voltage of Ar ion sputtering of 3 kV, and the sputtering rate of 11 nm/min. The measurement results of average film thickness of the copper oxide are provided in the column Copper oxide average film thickness in each table.

[HAST]

[0043] Samples for bonding reliability evaluation were produced and subjected to HAST evaluation, and the bonding reliability of the ball bonded part under high-temperature and high-humidity environment or high-temperature environment was determined by the bonding longevity of the ball bonded part. The sample for bonding reliability evaluation was produced by performing ball bonding using a commercially available wire bonder on electrodes formed by deposing an Al-1.0% Si0.5% Cu alloy with a thickness of 0.8 m on a Si substrate on a common metal frame, followed by encapsulation with a commercially available epoxy resin. The balls were formed while N.sub.2+5% H.sub.2 gas was supplied at a flow rate of 0.4 to 0.6 L/min, and their size was in the range of 33 to 34 m in diameter.

[0044] For the HAST evaluation, an unsaturated pressure cooker was used, and the produced sample for bonding reliability evaluation was exposed under high-temperature and high-humidity environment with temperature of 130 C. and relative humidity of 85%, and 7V bias was applied. A shear test was conducted on the ball bonded part every 48 hours, and the time when the value of shear strength was of the initially obtained shear strength was determined as the bonding longevity of the ball bonded part. The shear test after the high-temperature and high-humidity test was performed by removing the resin by acid treatment to expose the ball bonded part.

[0045] A tester manufactured by DAGE was used as a shear tester in HAST evaluation. The value of shear strength is the average value of the values measured at 10 points in the ball bonded part selected at random. In the evaluation above, the bonding longevity being less than 96 hours was determined to be practically unacceptable to be marked with a symbol of cross, being 96 hours to less than 144 hours was determined to be practicable but with some problem to be marked with a symbol of triangle, being 144 hours to less than 192 hours was determined to be practically acceptable to be marked with a symbol of circle, being 192 hours or longer was determined to be excellent to be marked with a symbol of double circle in the column HAST in each table. Only the symbol cross indicates fail and the other symbols indicate pass.

[FAB Shape]

[0046] In the evaluation of ball formability (FAB shape) in the ball, the balls before bonding were taken and observed, and the presence/absence of voids on the ball surface and the presence/absence of deformation of the ball, which should be spherical, were determined. If any one of them occurred, the sample was determined as fail. The balls were formed by blowing N.sub.2 gas at a flow rate of 0.5 L/min in order to suppress oxidation in the melting process. The diameter of the ball was 1.7 times as large as the wire diameter. For one condition, 50 balls were observed. An SEM was used for observation. In the evaluation of the ball formability, a case in which five or more failures occurred was determined to be problematic to be marked with a symbol of cross, a case of three or four failures was determined to be practicable but somewhat problematic to be marked with a symbol of triangle, a case of one or two failures was determined to be no problem to be marked with a symbol of circle, and a case in which no failure occurred was determined to be excellent to be marked with a symbol of double circle in the column FAB shape in each table. Only the symbol cross indicates fail and the other symbols indicate pass.

[Wedge Bondability]

[0047] The wedge bondability in the wire bonded part was evaluated by bonding 1000 wires to leads of a lead frame and determined by the frequency of separation of the bonds. The lead frame used was an Fe-42 at % Ni alloy lead frame with 1 to 3 m Ag plated. In this evaluation, considering a condition severer than usual, the stage temperature was set to 150 C., lower than the typical setting temperature range. In the evaluation above, a case in which 11 or more failures occurred was determined to be unacceptable to be marked with a symbol of cross, a case 6 to 10 failures was determined to be practicable but with some problem to be marked with a symbol of triangle, a case of 1 to 5 failures was determined to be acceptable to be marked with a symbol of circle, a case of no failure was determined to be excellent to be marked with a symbol of double circle in the column Wedge bondability in each table. Only the symbol cross indicates fail and the other symbols indicate pass.

[Crushed Shape]

[0048] In the evaluation of the crushed shape of the ball bonded part, the ball bonded part was observed from immediately above after bonding and its circularity was determined. For a bonding counterpart, an electrode in which an Al-0.5% Cu alloy was formed as a film with a thickness of 1.0 m on a Si substrate was used. An optical microscope was used for observation, and 200 points were observed for one condition. Being elliptic with large deviation from a perfect circle and being anisotropic in deformation were determined to be faulty in the crushed shape of the ball bonded part. In the evaluation above, a case in which 6 or more failures occurred was determined to be unacceptable to be marked with a symbol of cross, a case of 4 to 5 failures was determined to be practicable but with some problem to be marked with a symbol of triangle, a case of 1 to 3 failures was determined to be acceptable to be marked with a symbol of circle, a case in which a favorable circle was obtained for all was determined to be especially excellent to be marked with a symbol of double circle in the column Crushed shape in each table.

TABLE-US-00001 TABLE 1 Ingredient content(% by mass) First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 1 0.05 0.05 2 0.04 0.04 3 0.03 0.03 4 0.05 0.05 5 0.03 0.03 6 0.05 0.05 7 0.8 0.8 8 0.8 0.8 9 0.9 0.9 10 1.0 1.0 11 0.8 0.8 12 0.9 0.9 13 0.8 0.8 14 0.8 0.8 15 2.8 2.8 16 2.9 2.9 17 2.8 2.8 18 2.7 2.7 19 2.9 2.9 20 3.0 3.0 21 2.8 2.8 22 2.7 2.7 Crystal Average film grain thickness of Diameter Evaluation result size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 1 1.4 0.007 20 2 1.5 0.003 20 3 1.4 0.005 20 4 1.0 0.013 20 5 1.1 0.010 20 6 2.6 0.009 20 7 1.0 0.004 20 8 1.1 0.0005 20 9 1.2 0.0006 20 10 2.7 0.008 20 11 0.5 0.009 20 12 1.1 0.008 20 13 1.2 0.008 20 14 1.2 0.007 20 15 1.1 0.007 20 16 1.1 0.0008 20 17 1.0 0.006 20 18 1.2 0.003 20 19 1.1 0.007 20 20 1.1 0.006 20 21 1.0 0.003 20 22 1.2 0.010 20

TABLE-US-00002 TABLE 2 Ingredient content(% by mass) First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 23 0.03 0.02 0.05 24 0.4 0.5 0.9 25 0.3 0.5 0.8 26 0.3 0.6 0.9 27 0.3 0.5 0.8 28 0.3 0.5 0.8 29 0.4 0.5 0.9 30 0.3 0.5 0.8 31 0.3 0.4 0.7 32 0.3 0.5 0.8 33 0.3 0.5 0.8 34 0.3 0.6 0.9 35 0.3 0.5 0.8 36 0.2 0.2 0.6 1.0 37 0.2 0.2 0.5 0.9 38 0.2 0.2 0.5 0.9 39 0.2 0.2 0.5 0.9 40 0.2 0.2 0.6 1.0 41 0.2 0.2 0.5 0.9 42 0.2 0.2 0.5 0.9 43 0.2 0.2 0.5 0.9 Crystal Average film grain thickness of Diameter Evaluation result size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 23 2.6 0.003 20 24 1.0 0.006 20 25 1.1 0.010 20 26 1.0 0.004 20 27 1.2 0.008 20 28 1.2 0.010 20 29 1.2 0.003 20 30 1.2 0.008 20 31 1.1 0.010 20 32 1.2 0.005 20 33 1.3 0.002 20 34 1.3 0.004 20 35 1.3 0.007 20 36 1.2 0.005 20 37 1.2 0.008 20 38 1.1 0.008 20 39 1.2 0.010 20 40 1.2 0.005 20 41 1.3 0.010 20 42 1.1 0.005 20 43 1.0 0.005 20

TABLE-US-00003 TABLE 3 Ingredient content(% by mass) First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 44 0.7 0.7 Ti: 0.0001 45 3.0 3.0 B: 0.0005 46 0.5 0.5 P: 0.005 47 0.05 0.05 Mg: 0.01 48 1.0 1.0 Ca: 0.03 49 0.3 0.3 La: 0.05 50 0.1 0.1 As: 0.005 51 0.03 0.03 Te: 0.001 52 0.5 0.5 Se: 0.0005 53 0.4 0.5 0.9 Ti 0.0001 54 0.3 0.5 0.8 P 0.005 55 0.3 0.6 0.9 B 0.0005 56 0.3 0.5 0.8 Mg 0.01 57 0.3 0.5 0.8 Ca 0.03 58 0.4 0.5 0.9 La 0.05 59 0.3 0.5 0.8 As 0.005 60 0.3 0.4 0.7 Te 0.001 61 0.2 0.2 0.5 0.9 Se 0.0005 62 0.05 0.05 Ti: 0.0005, B: 0.0005 63 0.3 0.3 P: 0.005, Mg: 0.005 64 0.2 0.2 Ca: 0.025, La: 0.025 65 1.5 1.5 As: 0.005, Te: 0.005 66 0.5 0.5 Te: 0.001, Se: 0.001 Crystal Average film grain thickness of Diameter Evaluation result size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 44 0.8 0.015 20 45 1.0 0.001 20 46 1.1 0.002 20 47 1.2 0.004 20 48 1.3 0.009 20 49 1.0 0.009 20 50 0.9 0.004 20 51 1.2 0.013 20 52 1.2 0.005 20 53 1.1 0.008 18 54 1.0 0.004 18 55 2.6 0.009 18 56 0.5 0.010 18 57 1.3 0.008 18 58 1.0 0.004 18 59 1.0 0.003 18 60 1.1 0.003 18 61 1.5 0.008 18 62 2.7 0.008 20 63 1.5 0.004 20 64 1.0 0.005 20 65 1.1 0.009 20 66 0.9 0.007 20

TABLE-US-00004 TABLE 4 Ingredient content(% by mass) First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 67 0.5 0.5 Ag: 0.0005 68 0.05 0.05 Au: 0.001 69 0.3 0.3 Ag: 0.005 Au: 0.005 70 0.2 0.2 Au: 0.07 71 0.4 0.5 0.9 Ag 0.01 72 0.3 0.5 0.8 Ag 0.01 73 0.3 0.6 0.9 Ag 0.01 74 0.4 0.5 0.9 Ag 0.01 75 0.4 0.5 0.9 B 0.0005 Ag 0.01 76 0.3 0.5 0.8 P 0.005 Ag 0.01 77 0.3 0.5 0.8 Ag 0.01 78 0.3 0.5 0.8 Au 0.01 79 0.3 0.5 0.8 Au 0.01 80 0.3 0.4 0.7 Au 0.01 81 0.2 0.2 0.5 0.9 Au 0.01 82 0.8 0.8 Ag 0.01 83 0.7 0.7 Ag 0.01 84 0.8 0.8 Ti 0.0005 Ag 0.01 B 0.0005 85 0.8 0.8 P 0.005 Ag 0.01 B 0.005 86 0.8 0.8 Ag 0.5 87 0.8 0.8 Ag 0.5 88 0.7 0.7 Au 0.5 89 0.8 0.8 Au 0.5 90 0.7 0.7 Ti: 0.0001 Ag: 0.0005 91 3.0 3.0 B: 0.0005 Au: 0.001 92 0.5 0.5 P: 0.005 Ag: 0.005 Au: 0.005 Crystal Average film grain thickness of Diameter Evaluation result size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 67 1.1 0.014 20 68 1.2 0.003 20 69 1.2 0.001 20 70 2.3 0.0005 20 71 1.2 0.006 20 72 1.2 0.004 20 73 1.2 0.005 20 74 1.2 0.010 20 75 1.1 0.007 20 76 1.0 0.005 20 77 2.8 0.008 20 78 0.6 0.007 20 79 1.3 0.001 20 80 1.3 0.002 20 81 1.3 0.002 20 82 1.2 0.005 20 83 1.3 0.008 20 84 1.2 0.007 20 85 1.0 0.003 20 86 1.0 0.004 20 87 1.0 0.004 20 88 1.0 0.005 20 89 1.1 0.005 20 90 1.0 0.005 20 91 1.1 0.009 20 92 0.9 0.007 20

TABLE-US-00005 TABLE 5 Ingredient content(% by mass) First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 93 1.5 1.5 0.1 94 0.5 0.5 0.5 95 2.0 2.0 0.7 96 0.03 0.03 1.15 98 0.05 0.05 Mg: 0.01 0.1 99 1.0 1.0 Ca: 0.03 0.5 100 0.05 0.05 0.5 101 0.06 0.06 0.5 102 0.06 0.06 0.5 103 0.06 0.06 0.4 Crystal Average film grain thickness of Diameter Evaluation result size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 93 1.1 0.0008 20 94 1.2 0.001 20 95 1.1 0.004 20 96 1.0 0.008 20 98 1.1 0.014 20 99 1.2 0.003 20 100 1.2 0.003 20 101 1.2 0.014 20 102 1.2 0.009 20 103 1.1 0.006 20

TABLE-US-00006 TABLE 6 Ingredient content(% by mass) Comparative First element Second Third Example Ni Pt Ir Rh Zn Ga Ge In Total element element Pd 1 3.1 3.1 2 2.0 2.0 4.0 3 0.02 0.02 4 0.01 0.01 0.02 5 3.1 3.1 6 4.0 4.0 Crystal Average film grain thicknes sof Diameter Evaluation result Comparative size copper oxide of wire FAB Crushed Wedge Example (m) (m) (m) HAST shape shape bondability 1 1.2 0.008 20 X X 2 1.2 0.002 20 X X 3 1.1 0.010 20 X 4 1.2 0.008 20 X 5 1.1 0.010 20 X X 6 1.3 0.008 20 X X

Evaluation Result

[0049] As shown in Tables 1 and 2, in the copper alloy bonding wires in Examples 1 to 103 in which the concentration of the first element is in total 0.03 to 3.0% by mass, it has been confirmed that bonding reliability of the ball bonded part is achieved in the HAST test under the high-temperature and high-humidity environment with temperature of 130 C. and relative humidity of 85%.

[0050] In all of the bonding wires in Examples 1 to 103 in which the average film thickness of copper oxide on the wire surface is in the range of 0.0005 to 0.02 m, the HAST evaluation result is satisfactory.

[0051] Of the bonding wires in Examples, in the bonding wires in Examples 1 to 5, 7 to 9, 12 to 22, 24 to 54, 57 to 61, 63 to 69, 71 to 76, and 78 to 103 in which the area reduction ratio in wire drawing is 10% or more in at least half of all the dies and the heat treatment temperature in heat treatment after wire drawing is 600 C. or lower, the average crystal grain size (m) in core cross section in the direction vertical to the wire axis of the bonding wire is in the range of 0.02R+0.4 or more to 0.1R+0.5 or less (where R is the wire diameter (m)). Here, when the evaluation results of Examples 7 to 14 with the first element content of 0.8 to 1.0% by mass are compared, the wedge bondability and the crushed shape of the ball bond are better in the bonding wire with the average crystal grain size within the range above (Examples 7 to 9, Examples 12 to 14) than in the bonding wire with the average crystal grain size outside the range above (Examples 10 and 11). This result indicates that when the average crystal grain size (m) in core cross section in the direction vertical to the wire axis of the bonding wire is in the range of 0.02R+0.4 or more to 0.1R+0.5 or less (where R is the wire diameter (m)), the wedge bondability and the crushed shape of the ball bond are satisfactory.

[0052] In Example 11, since the heat treatment temperature is low, 300 C. or lower, the average crystal grain size is smaller than the lower limit of the preferable range, and the wedge bondability is triangle and slightly worse. In Example 10, since the heat treatment temperature is high, 700 C. or higher, the average crystal grain size exceeds the upper limit of the preferable range. Consequently, in Example 10, the crushed shape is triangle and slightly worse.

[0053] In the bonding wires in Examples 24 to 43 including two or more first elements, the result of HAST test is more satisfactory than in the bonding wires in Examples 7 to 14 including a single first element with the equivalent content. This result indicates that in the bonding wire including two or more first elements, the ball bond reliability is even more satisfactory in the HAST test under the high-temperature and high-humidity environment with temperature of 130 C. and relative humidity of 85%.

[0054] Of the bonding wires in Examples, in the bonding wires in Examples 44 to 66 further including 0.0001 to 0.050% by mass of each of the second elements, the crushed shape of the ball bonded part is satisfactory.

[0055] Of the bonding wires in Examples, in the bonding wires in Examples 67 to 92 including in total 0.0005 to 0.5% by mass of at least one or more kinds of elements (third element) selected from Ag and Au, the crushed shape of the ball bonded part is satisfactory.

[0056] Of the bonding wires in Examples, in the bonding wires in Examples 93 to 103 further including 1.15% by mass or less of Pd, it has been confirmed that the bonding reliability of the ball bonded part is even more satisfactory in the HAST test under the high-temperature and high-humidity environment with temperature of 130 C. and relative humidity of 85%. Of the bonding wires in Examples, in the bonding wires in Examples 75, 76, 84, 85, and 90 to 92 including 0.0001 to 0.050% by mass of each of the second elements and in total 0.0005 to 0.07% by mass of at least one or more kinds of elements (third element) selected from Ag and Au, in addition to the first element, all of the HAST evaluation results, the wedge bondability, and the crushed shape of the ball bonded part are satisfactory. Among others, in Examples 75 and 76 including two or more first elements, the HAST evaluation result is particularly good.

[0057] Of the bonding wires in Examples, in the bonding wires in Examples 98 to 99 further including 0.0001 to 0.050% by mass of each of the second elements and 1.15% by mass or less of Pd, in addition to the first element, the HAST evaluation result is even more satisfactory, and the FAB shape, the wedge bondability, and the crushed shape of the ball bonded part are satisfactory.

[0058] On the other hand, of the bonding wires in Comparative Examples, in the bonding wires in Comparative Examples 3 and 4 in which the total concentration of the first element is less than 0.03% by mass, bonding reliability of the ball bonded part is not achieved in the HAST test, and in the bonding wires in Comparative Examples 1, 2, 5, and 6 in which the total concentration of the first element is greater than 3% by mass, the FAB shape and the wedge bondability are bad.