TW202136533A - Al bonding wire even when the semiconductor device is continuously used in a high-temperature environment, the progress of the recrystallization of the bonding wire can be suppressed - Google Patents

Abstract

The present invention provides an Al bonding wire capable of sufficiently obtaining the bonding reliability of the bonding portion of the bonding wire under a high temperature state in which a semiconductor device using the Al bonding wire is operated. The Al bonding wire contains 0.01 to 1% of Sc, and further contains a total of 0.01 to 0.1% of at least one of Y, La, Ce, Pr, and Nd. As a result, the recrystallization temperature of the metal wire rises, and even when the semiconductor device is continuously used in a high-temperature environment, the progress of the recrystallization of the bonding wire can be suppressed, preventing the strength of the metal wire from decreasing, thus sufficiently ensuring the reliability of the bonding portion after undergoing the high-temperature conditions for a long time.

Description

Al bonding wire

The present invention relates to an Al bonding wire.

之鋁接合線(以下，稱為「Al接合線」)之例。又，於使用Al接合線之功率半導體裝置中，作為接合方法，與半導體元件上電極之連接及與引線框架或基板上之電極之連接均使用楔型接合。In the semiconductor device, the electrode formed on the semiconductor element and the electrode on the lead frame or the substrate are connected by bonding wires. As the material used for the bonding wire, gold (Au) or copper (Cu) is used in integrated circuit semiconductor devices such as ultra-LSI (Large Scale Integration). On the other hand, aluminum is mainly used in power semiconductor devices. (Al). For example, Patent Document 1 shows that 300 μm is used in power semiconductor modules

An example of aluminum bonding wire (hereinafter referred to as "Al bonding wire"). In addition, in a power semiconductor device using Al bonding wires, as a bonding method, both the connection with the electrode on the semiconductor element and the connection with the electrode on the lead frame or the substrate use wedge bonding.

Power semiconductor devices using Al bonding wires are mostly used as semiconductor devices for high-power equipment such as air conditioners or solar power generation systems, and for vehicles. In these semiconductor devices, the bonding portion of the Al bonding wire is exposed to a high temperature of 100 to 300°C. When using a material composed of only high-purity Al as the Al bonding wire, it is difficult to use it in a high-temperature environment because the metal wire is prone to softening in such a temperature environment.

If an alloy containing scandium (Sc) (hereinafter referred to as "Sc") in Al is used, and _{Sc is precipitated in the form of Al 3} Sc, the Al bonding wire can be increased in strength. Patent Document 2 discloses a bonding wire containing Al as a main component and containing 0.05 to 1.0% of Sc. Due to the precipitation of Al ₃ Sc in the bonding wire, the best combination of electrical and mechanical properties can be obtained.

However, if a _{bonding wire in which Al 3} Sc is precipitated is used for bonding with the electrode of a semiconductor device, the metal wire has a high mechanical strength, which will cause the chip of the semiconductor device to crack and cannot be put into practical use. In this regard, Patent Document 3 discloses an invention in which the Al bonding wire contains Sc. In the bonding wire in the stage before bonding, the Al ₃ Sc is not precipitated by the previous melting treatment, and the bonding is performed after the bonding. The aging heat treatment to _{precipitate Al 3} Sc. _{Since Al 3} Sc is not precipitated during the bonding stage, the metal wire is softened, and the wafer does not crack during bonding. _{On the other hand, since Al 3} Sc is precipitated by the aging heat treatment performed after bonding, the strength of the metal wire is increased, and even if the semiconductor device is used in a high temperature environment, the metal wire can maintain sufficient strength. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-314038 [Patent Document 2] Japanese Patent Publication No. 2016-511529 [Patent Document 3] Japanese Patent Laid-Open No. 2014-47417

[The problem to be solved by the invention]

Even for a semiconductor device using an Al bonding wire containing Sc as described in Patent Document 3, the bonding reliability of the bonding portion of the bonding wire may not be sufficiently obtained in a high temperature state in which the semiconductor device is actuated.

The object of the present invention is to provide an Al bonding wire that can sufficiently obtain the bonding reliability of the bonding portion of the bonding wire under the high temperature state of the semiconductor device using the Al bonding wire. [Technical means to solve the problem]

In the Al bonding wire containing Sc, Al ₃ Sc is precipitated by the aging heat treatment after bonding, whereby the strength of the bonding wire can be increased as described in Patent Document 3. On the other hand, it is clarified that when the semiconductor device is continuously used in a high-temperature environment, the recrystallization of the Al bonding wire proceeds further, and as a result, the strength of the metal wire decreases.

In this regard, it is clarified that the Al bonding wire containing 0.01 to 1% of Sc contains 0.01 to 0.1% of yttrium, lanthanum, cerium, cerium, neodymium (hereinafter referred to as "Y, La, At least one of Ce, Pr, Nd"), the recrystallization temperature of the metal wire will increase, even when the semiconductor device is continuously used in a high temperature environment, the recrystallization of the bonding wire can be suppressed, and the strength of the metal wire can be prevented decline.

The present invention was completed based on the above-mentioned knowledge, and the gist of the present invention is as follows. [1] An Al bonding wire characterized in that it contains 0.01-1% Sc in mass %, and further contains at least one of Y, La, Ce, Pr, and Nd in a total of 0.01-0.1%, and the remainder contains Al and inevitable impurities. [2] The Al bonding wire as described in [1] above, wherein the average crystal grain size in a cross section perpendicular to the longitudinal direction of the metal wire (hereinafter also referred to as "C cross section") is 0.1 to 50 μm. [3] The Al bonding wire as described in [1] or [2] above, wherein in the cross section perpendicular to the longitudinal direction of the metal wire (C section), the angle difference between the crystal <111> orientation and the longitudinal direction of the metal wire The area ratio of crystals within 15° is 30% to 90%. [4] The Al bonding wire as described in any one of [1] to [3] above, wherein the Vickers hardness is in the range of Hv20-40. [5] The Al bonding wire as described in any one of [1] to [4] above, wherein the metal wire has a diameter of 50 to 600 μm. [Effects of Invention]

In the present invention, since the Al bonding wire contains 0.01 to 1% of Sc, and further contains 0.01 to 0.1% of at least one of Y, La, Ce, Pr, and Nd in total, the recrystallization temperature of the metal wire increases, even if When the semiconductor device is continuously used in a high temperature environment, the recrystallization of the bonding wire can also be suppressed, and the strength of the metal wire can be prevented from decreasing, so the reliability of the bonding part after a high temperature long time course can be fully ensured.

Regarding the bonding wire containing Sc in the Al bonding wire, as described in Patent Document 3, the prior melting treatment causes the Sc to be forced into a solid solution without precipitation of Al ₃ Sc. Therefore, the wire softens during the bonding stage, and the No chip cracking occurs during bonding. _{Then, Al 3} Sc is precipitated due to the aging heat treatment performed after the bonding. As a result, the strength of the metal wire increases and the recrystallization temperature rises, which prevents the recrystallization in use at high temperatures and maintains the metal wire strength.

However, as described above, it has been clarified that even for semiconductor devices with Al bonding wires deposited with Sc, if the semiconductor devices are operated for a long time at a high temperature, the bonding strength of the bonding portions of the bonding wires will decrease. The joint reliability is not sufficiently obtained. Observing the cross-section of the bonding wire of the semiconductor device after being operated at a high temperature for a long time, it is estimated that the crystal grain size of the metal wire is increased compared with the time of bonding. As a result, the strength of the metal wire is reduced, and the reliability of the joint is reduced.

In contrast, in the present invention, in an Al bonding wire containing 0.01 to 1% of Sc, in addition to Sc, it further contains a total of 0.01 to 0.1% of at least one of Y, La, Ce, Pr, and Nd (hereinafter, also Referred to as "Y, La, etc."). As a result, the recrystallization temperature of the metal wire rises, and even when the semiconductor device is continuously used for a long time in a high-temperature environment, the progress of the recrystallization of the bonding wire can be sufficiently suppressed, and the strength of the metal wire can be prevented from decreasing. Hereinafter, a detailed description will be given.

The Al bonding wire of the present invention contains 0.01-1% Sc in mass%, and further contains at least one of Y, La, Ce, Pr, and Nd in a total of 0.01-0.1%. The remainder contains Al and unavoidable Impurities. Wire drawing is performed on the material with this composition to produce a bonding wire with a specific wire diameter. In order to forcibly solid-solve Sc, Y, La, etc. before the wire drawing process, during the wire drawing process, or after the wire drawing process is completed, it is preferable to perform a melting heat treatment. The melting heat treatment conditions are preferably 570 to 640°C for 1 to 3 hours.

After the wire drawing process is completed and the above-mentioned melting heat treatment has been carried out, the quenching and tempering heat treatment for softening the metal wire is carried out in the subsequent stage. It is also possible to add quenching and tempering heat treatment in the middle of wire drawing. By quenching and tempering heat treatment, the crystalline structure of the metal wire is changed from the processed structure to the recrystallized structure. Thereby, the crystalline structure becomes a recrystallized structure, so that the softening of the metal wire can be achieved. As the condition of the tempering heat treatment, it is preferably 250 to 300°C for 5 to 15 seconds. Thereby, the crystal structure can be made into a recrystallized structure without precipitation of solid solution Sc, Y, La, etc.

In the present invention, it is preferable to prevent Sc, Y, La, etc. from being precipitated in the metal wire due to the melting treatment during the metal wire manufacturing process as described above. In the case where the melting heat treatment is not performed, since precipitates such as Sc, Y, and La are deposited in the metal wire, the Vickers hardness of the metal wire becomes a hardness exceeding Hv40. On the other hand, as a result of the melting heat treatment and the quenching and tempering heat treatment, Sc, Y, La, etc. are forcibly dissolved, and the crystalline structure becomes a recrystallized structure, whereby the Vickers hardness of the metal wire becomes Hv40 or less, resulting in softness. change. By using the softened Al bonding wire of the present invention to bond the semiconductor electrode, the chip of the semiconductor electrode will not be cracked.

After the bonding, in order to precipitate Sc, Y, La, etc. in the bonding wire, the semiconductor device including the bonding wire is subjected to an aging heat treatment. As a result of the aging heat treatment, Sc, Y, La, etc. in the bonding wire are precipitated. Sc is _{precipitated in the form of Al 3} Sc, Y is precipitated in the form of Al ₃ Y, La is precipitated in the form of Al ₁₁ La ₃ , Ce is precipitated in the form of Al ₁₁ Ce ₃ , and Pr is precipitated in the form of Al ₁₁ Pr ₃ Form precipitation, Nd is precipitated in the form of _{Al 11} Nd _3. These precipitates are formed in the metal wire, and as a result, the metal wire is precipitation strengthened, and the strength of the metal wire increases. The aging heat treatment conditions are preferably 250 to 400°C for 30 to 60 minutes.

Immediately after aging heat treatment, and after being subjected to a high temperature and long time course under less stringent conditions, the Al bonding wire containing only Sc, the Al bonding wire containing Sc, Y, La, etc. can achieve the precipitation of precipitates It hardens and does not cause excessive recrystallization, so the mechanical strength can be maintained, and the reliability of the bonding part between the bonding wire and the electrode of the semiconductor device is fully maintained. However, it has been clarified that when kept under a more severe environment, that is, under a higher temperature and longer environment, the reliability of the joint portion of the Al bonding wire containing only Sc is reduced. In contrast, it can be seen that if it is the Al bonding wire of the present invention that contains Y, La, etc. in addition to Sc, the reliability of the bonding portion is ensured even after exposure to such a more severe environment.

Describes the joint reliability evaluation test after high temperature and long-term history. Regarding the composition of the bonding wire used, there are the Al bonding wire of the comparative example containing only 0.5% by mass of Sc, and the Al bonding wire of the present invention containing 0.5% of Sc and 0.1% of Y. The wire diameter of the metal wire after drawing is 200 μm. In the middle of the wire drawing step, the melting heat treatment is performed to force Sc and Y into solid solution, and the metal wire after wire drawing is subjected to tempering heat treatment to adjust the Vickers hardness of the bonding wire to Hv40 or less.

In the semiconductor device, the first bonding portion between the semiconductor wafer and the bonding wire, and the second bonding portion between the external terminal and the bonding wire are all wedge bonding.

The high-temperature long-term history is carried out by the power cycle test. The power cycle test is to repeatedly heat and cool the semiconductor device with Al bonding wire. The heating is performed for 2 seconds until the temperature of the junction of the bonding wire in the semiconductor device reaches 140°C, and thereafter, it is cooled for 5 seconds until the temperature of the junction becomes 30°C. Repeat the above heating and cooling cycles 200,000 times.

After the above-mentioned high-temperature long-term history, the joint shear strength of the first joint was measured, and the reliability of the joint was evaluated. As a result, regarding the Al bonding wire containing only 0.5% by mass of Sc, the shear strength of the bonding portion was less than 50% compared with the initial stage, and the reliability of the bonding portion was insufficient. In contrast, with regard to the Al bonding wire of the present invention containing 0.5% Sc and 0.1% Y, the shear strength of the joint is 90% or more compared with the initial stage, and the reliability of the joint is sufficiently ensured.

The composition of the bonding wire of the present invention will be described. % Means mass%.

"0.01～1% of Sc" Since the Al bonding wire contains more than 0.01% Sc, it can be supplemented with the following compound addition effects of Y, La, etc., to exert the precipitation strengthening effect of the metal wire and prevent the recrystallization of the semiconductor device during high temperature and long-term use Effect. Sc is more preferably 0.1% or more, still more preferably 0.3% or more, and still more preferably 0.5% or more. On the other hand, if the Sc content exceeds 1%, the hardness of the metal wire becomes too high, which may cause wafer cracks, deterioration of bonding properties, and deterioration of joint reliability. Therefore, the upper limit is set to 1%. Sc is more preferably 0.8% or less.

"At least one of Y, La, Ce, Pr, Nd in total 0.01～0.1%" By containing at least one of Y, La, Ce, Pr, Nd (Y, La, etc.) in a total of 0.01% or more, it can complement the composite addition effect of the above-mentioned Sc, and exert the precipitation strengthening effect of the metal wire, and the semiconductor device The effect of preventing recrystallization in high temperature and long-term use. Y, La, Ce, Pr, and Nd all exert the same effect. The total content of Y, La, etc. is more preferably 0.03% or more. More preferably, it is 0.05% or more. On the other hand, if the total content of Y, La, etc. exceeds 0.1%, the hardness of the metal wire becomes too high, which may cause chip cracks, deterioration of bonding properties, and deterioration of joint reliability. Therefore, the upper limit is set to 0.1% . The total content of Y, La, etc. is more preferably 0.08% or less.

In the concentration analysis of Sc, Y, La, etc. in the bonding wire, an ICP (Inductively Coupled Plasma) emission spectrometer and ICP mass spectrometer can be used. The content of Sc, Y, La, etc. shown in the present invention is based on the concentration measured by ICP emission spectrometry or ICP mass spectrometry. The remaining part of the bonding wire contains Al and unavoidable impurities. As the inevitable impurity elements, Si, Fe, and Cu can be cited. The smaller the total content of unavoidable impurities, the more the variation in material properties can be suppressed, which is preferable. Better results can be obtained by using aluminum with a purity of 4 N (Al: 99.99% or more) as the aluminum raw material when manufacturing metal wires.

"Average crystal grain size of metal wire" In the present invention, it is preferable that the average crystal grain size in the cross section (C cross section) perpendicular to the longitudinal direction of the metal wire of the bonding wire is 0.1 to 50 μm. As a method for measuring the average crystal grain size, use EBSD (Electron Back Scatter Diffraction Patterns) and other measuring methods to find the area of each crystal grain, and set the area of each crystal grain as a circle. The average of the diameter of the time. If the average crystal grain size is 0.1 μm or more, the recrystallization is moderately performed by the tempering heat treatment during wire drawing, and the melting heat treatment is performed during the metal wire manufacturing process to forcibly solid-dissolve the components contained in the metal wire, which complements each other. The softening of the metal wire can prevent chip breakage and deterioration of the bonding part during bonding. On the other hand, if the average crystal grain size exceeds 50 μm, it indicates that the recrystallization of the metal wire has proceeded excessively. Even if precipitates are formed by aging heat treatment, it is difficult to obtain sufficient strength and the reliability of the joint may decrease. Due to the quenching and tempering heat treatment during the wire drawing process of the metal wire, the average crystal grain size in the C section of the metal wire can be 0.1-50 μm.

"Line <111> Azimuth Area Rate" In the present invention, it is preferable that in the cross-section perpendicular to the longitudinal direction of the bonding wire (C-section), the area ratio of the crystal whose angle difference between the orientation of the crystal <111> and the longitudinal direction of the metal wire is within 15° (hereinafter referred to as "<111> azimuth area rate") is 30 to 90%. EBSD can be used when measuring <111> azimuth area ratio. The section perpendicular to the long side of the bonding line is used as the inspection surface, and the analysis software attached to the device can be used to calculate the <111> azimuth area ratio. In the process of obtaining the <111> azimuth area ratio, the part where the crystal orientation cannot be measured, or the part where the reliability of the measurement orientation analysis is low, etc. is excluded for subsequent calculation. If the azimuth area ratio of <111> is 90% or less, recrystallization is performed moderately by the tempering heat treatment during wire drawing, and the melting heat treatment is performed during the manufacturing process of the wire to force the components of the wire to form a solid solution. They complement each other and soften the metal wire, which can prevent chip breakage and deterioration of the bonding part during bonding. On the other hand, if the azimuth area ratio of <111> is less than 30%, it indicates that the recrystallization of the metal wire has proceeded excessively. Even if precipitates are formed by aging heat treatment, it is difficult to obtain sufficient strength and the reliability of the joint is reduced. The fear. Due to the quenching and tempering heat treatment during the drawing process of the metal wire, the area ratio of the <111> orientation in the section perpendicular to the long side of the metal wire can be set to 30-90%.

"Vickers Hardness of Metal Wire" In the present invention, it is preferable that the Vickers hardness is in the range of Hv20-40 in the cross-section (C-section) perpendicular to the longitudinal direction of the metal wire of the bonding wire. By setting it to Hv40 or less, the chip does not crack during bonding and achieves good bonding properties. In addition, it is possible to easily form a circuit for wiring the semiconductor device. On the other hand, if the Vickers hardness drops below Hv20, it indicates that the recrystallization of the metal wire has proceeded excessively. Even if precipitates are formed by aging heat treatment, it is difficult to obtain sufficient strength and the reliability of the joint may decrease. . Therefore, the lower limit of Vickers hardness is preferably set to Hv20. As mentioned above, by performing the melting heat treatment during the manufacturing process of the metal wire to force the solid solution of the components contained in the metal wire, and then performing the quenching and tempering heat treatment during the wire drawing process, the Vickers hardness of the metal wire can be Hv20-40 Scope.

"Metal Wire Diameter" In the present invention, the diameter of the bonding wire is preferably 50 to 600 μm. For power devices, since large current flows, metal wires of 50 μm or more are usually used. However, if it is 600 μm or more, it becomes difficult to handle or the wire bonding machine is not compatible. Therefore, metal wires of 600 μm or less are used. String. [Example]

Aluminum with a purity of 99.99% by mass (4 N) and yttrium, lanthanum, cerium, cerium, and neodymium with a purity of 99.9% by mass or more were used as raw materials and melted to obtain Al alloys with the compositions shown in Tables 1 and 2. The alloy is made into an ingot, and the ingot is subjected to grooved rolling, and then subjected to wire drawing processing. At the stage where the diameter of the metal wire is 800 μm, the melting heat treatment is performed at 620°C for 3 hours, and then quenched in water. Thereafter, the final wire diameter was set to 200 μm to perform die wire drawing processing, and after the wire drawing processing was completed, a tempering heat treatment was performed at 270° C. for 10 seconds.

Using this metal wire, the average crystal grain size and the angle difference between the crystal <111> orientation and the metal wire longitudinal direction are performed in a cross section perpendicular to the longitudinal direction of the metal wire (C section). The area ratio of the crystals within 15° <111> azimuth area ratio), measurement of Vickers hardness. The measurement of the average crystal grain size is carried out as follows: the area of each crystal grain is obtained by the EBSD method, the area of each crystal grain is converted into the area of a circle, and the diameter is averaged. The <111> azimuth area ratio is measured by using EBSD in a section perpendicular to the longitudinal direction of the joint line, and the analysis software attached to the device is used to calculate the <111> azimuth area ratio. The Vickers hardness is measured by using a micro Vickers hardness tester to measure the hardness at the center of the C section in the radial direction.

In the semiconductor device, the semiconductor wafer electrode is Al-Cu, and the external terminal is Ag. The first bonding portion between the semiconductor wafer electrode and the bonding wire, and the second bonding portion between the external terminal and the bonding wire are all wedge-shaped bonding.

After bonding, an aging heat treatment was performed at 350°C for 45 minutes.

Regarding the bonding property of the bonding wire in the semiconductor device, the judgment is made based on the presence or absence of the bonding failure (unbonded) at the initial stage of the first bonding part (before the high-temperature long-term history). In the "Jointability" column of Tables 1 and 2, the ones that are joined are described as ○, and those that are not joined are described as x. Regarding the evaluation of chip cracks in semiconductor devices, acid is used to dissolve the metal on the surface of the pad, and the presence or absence of chip cracks under the pad is observed and evaluated with a microscope. In the "chip cracks" column of Tables 1 and 2, no cracks are recorded as ○, and cracks are recorded as x.

The high-temperature long-term history is carried out by the power cycle test. The power cycle test is to repeatedly heat and cool the semiconductor device with Al bonding wire. The heating is performed for 2 seconds until the temperature of the bonding portion of the bonding wire in the semiconductor device reaches 140°C, and thereafter, it is cooled for 5 seconds until the temperature of the bonding portion becomes 30°C. Repeat the above heating and cooling cycles 200,000 times.

After the above-mentioned high temperature and long time, the joint shear strength of the first joint was measured, and the reliability of the joint was evaluated. The shear strength measurement is performed in the form of comparison with the initial shear strength of the joint. In the "Reliability Test" column of Tables 1 and 2, the initial joint strength of 95% or more is described as ◎, 90% or more and less than 95% is described as ○, and 50% or more and less than 90% is described It is △, and less than 50% is recorded as ×.

The manufacturing conditions and manufacturing results are shown in Table 1 and Table 2. Y, La, Ce, Pr, Nd (Y, La, etc.) are represented as "second component". In Table 2, values whose content of ingredients are outside the range of the present invention and those whose evaluation results are outside the preferred range of the present invention are underlined.

[Table 1] No. Ingredient content (mass%) Wire quality Use performance Sc 2nd component Crystal size (μm) (111) Bearing (%) Hardness Hv Zygosity Chip crack Reliability test Y La Ce Pr Nd total Example of the present invention 1 0.01 0.01 0 0 0 0 0.01 49 56 twenty four 〇 〇 〇 2 0.01 0 0.01 0 0 0 0.01 43 57 29 〇 〇 〇 3 0.01 0 0 0.01 0 0 0.01 41 56 twenty four 〇 〇 〇 4 0.01 0 0 0 0.01 0 0.01 45 56 twenty four 〇 〇 〇 5 0.01 0 0 0 0 0.01 0.01 45 59 26 〇 〇 〇 6 0.01 0.1 0 0 0 0 0.1 twenty four 63 29 〇 〇 〇 7 0.01 0 0.1 0 0 0 0.1 twenty four 67 28 〇 〇 〇 8 0.01 0 0 0.1 0 0 0.1 twenty one 66 32 〇 〇 〇 9 0.01 0 0 0 0.1 0 0.1 twenty three 66 30 〇 〇 〇 10 0.01 0 0 0 0 0.1 0.1 29 65 29 〇 〇 〇 11 0.01 0.01 0.01 0 0 0 0.02 32 59 26 〇 〇 〇 12 0.01 0.01 0 0.01 0 0 0.02 36 58 28 〇 〇 〇 13 0.01 0.01 0 0 0.01 0 0.02 35 58 27 〇 〇 〇 14 0.01 0.01 0 0 0 0.01 0.02 36 61 29 〇 〇 〇 15 0.01 0.05 0.05 0 0 0 0.1 20 69 29 〇 〇 〇 16 0.01 0.05 0 0.05 0 0 0.1 twenty two 65 27 〇 〇 〇 17 0.01 0.05 0 0 0.05 0 0.1 twenty two 70 27 〇 〇 〇 18 0.01 0.05 0 0 0 0.05 0.1 25 68 27 〇 〇 〇 19 0.5 0.01 0 0 0 0 0.01 14 72 26 〇 〇 ◎ 20 0.5 0 0.01 0 0 0 0.01 10 71 29 〇 〇 ◎ twenty one 0.5 0 0 0.01 0 0 0.01 14 70 27 〇 〇 ◎ twenty two 0.5 0 0 0 0.01 0 0.01 12 71 28 〇 〇 ◎ twenty three 0.5 0 0 0 0 0.01 0.01 11 73 25 〇 〇 ◎ twenty four 0.5 0.1 0 0 0 0 0.1 9 69 33 〇 〇 ◎ 25 0.5 0 0.1 0 0 0 0.1 13 70 31 〇 〇 ◎ 26 0.5 0 0 0.1 0 0 0.1 10 69 31 〇 〇 ◎ 27 0.5 0 0 0 0.1 0 0.1 12 69 30 〇 〇 ◎ 28 0.5 0 0 0 0 0.1 0.1 4 73 33 〇 〇 ◎ 29 0.5 0.01 0.01 0 0 0 0.02 12 66 30 〇 〇 ◎ 30 0.5 0.01 0 0.01 0 0 0.02 4 71 33 〇 〇 ◎ 31 0.5 0.01 0 0 0.01 0 0.02 6 74 32 〇 〇 ◎ 32 0.5 0.01 0 0 0 0.01 0.02 9 70 32 〇 〇 ◎ 33 0.5 0.05 0.05 0 0 0 0.1 3 71 32 〇 〇 ◎ 34 0.5 0.05 0 0.05 0 0 0.1 11 71 32 〇 〇 ◎ 35 0.5 0.05 0 0 0.05 0 0.1 5 74 32 〇 〇 ◎ 36 0.5 0.05 0 0 0 0.05 0.1 2 77 34 〇 〇 ◎ 37 1.0 0.01 0 0 0 0 0.01 2.0 78 34 〇 〇 〇 38 1.0 0 0.01 0 0 0 0.01 1.6 76 32 〇 〇 〇 39 1.0 0 0 0.01 0 0 0.01 1.7 74 32 〇 〇 〇 40 1.0 0 0 0 0.01 0 0.01 1.1 76 32 〇 〇 〇 41 1.0 0 0 0 0 0.01 0.01 1.3 77 36 〇 〇 〇 42 1.0 0.1 0 0 0 0 0.1 1.4 77 34 〇 〇 〇 43 1.0 0 0.1 0 0 0 0.1 1.8 81 36 〇 〇 〇 44 1.0 0 0 0.1 0 0 0.1 1.5 81 34 〇 〇 〇 45 1.0 0 0 0 0.1 0 0.1 0.9 82 35 〇 〇 〇 46 1.0 0 0 0 0 0.1 0.1 1.1 78 34 〇 〇 〇 47 1.0 0.01 0.01 0 0 0 0.02 1.4 80 34 〇 〇 〇 48 1.0 0.01 0 0.01 0 0 0.02 1.2 80 37 〇 〇 〇 49 1.0 0.01 0 0 0.01 0 0.02 0.7 81 34 〇 〇 〇 50 1.0 0.01 0 0 0 0.01 0.02 1.2 82 36 〇 〇 〇 51 1.0 0.05 0.05 0 0 0 0.1 1.0 84 37 〇 〇 〇 52 1.0 0.05 0 0.05 0 0 0.1 0.9 86 38 〇 〇 〇 53 1.0 0.05 0 0 0.05 0 0.1 0.1 88 38 〇 〇 〇 54 1.0 0.05 0 0 0 0.05 0.1 0.8 86 38 〇 〇 〇

[Table 2] No. Ingredient content (mass%) Wire quality Use performance Sc 2nd component Crystal size (μm) (111) Bearing (%) Hardness Hv Zygosity Chip crack Reliability test Y La Ce Pr Nd total Comparative example 1 0.005 0 0 0 0 0 0 59 63 twenty four 〇 〇 X 2 0.005 0.05 0 0 0 0 0.05 49 56 27 〇 〇 X 3 0.005 0.15 0 0 0 0 0.15 43 55 41 X X X 4 0.5 0 0 0 0 0 0 9 68 29 〇 〇 △ 5 0.5 0.005 0 0 0 0 0.005 12 73 30 〇 〇 △ 6 0.5 0.15 0 0 0 0 0.15 9 71 43 X X X 7 1.5 0 0 0 0 0 0 0.6 86 45 X X X 8 1.5 0.005 0 0 0 0 0.005 0.7 84 41 X X X 9 1.5 0.05 0 0 0 0 0.05 0.8 87 42 X X X 10 1.5 0.15 0 0 0 0 0.15 0.08 97 46 X X X

Inventive example Nos. 1 to 54 in Table 1 are examples of the present invention. The composition range of the metal wire is within the scope of the present invention, and the average grain size of the metal wire, <111> azimuth area ratio, and Vickers hardness are all within the preferred range of the present invention. The evaluation results of bonding properties and chip cracks are all within the scope of the present invention. Is "○". As a result, it contains the components specified in the present invention, and the contained elements are forced into solid solution by melting heat treatment, and moderate recrystallization is carried out by tempering heat treatment.

In the evaluation of the joint reliability after high temperature and long-term history of the present invention example Nos. 1 to 54, all were "○" or "◎". The reason is that the components specified in the present invention are contained, and Sc, Y, La, etc. are precipitated by the aging heat treatment after bonding. As a result, the precipitation strengthening of the metal wire is realized, and the recrystallization temperature is increased, which prevents high temperature and long time. The recrystallization in the process proceeds. In particular, regarding Example Nos. 19 to 36 of the present invention, the Sc content was within the preferable range of the present invention, and the reliability evaluation results of the joints were all "◎".

Comparative example Nos. 1 to 10 in Table 2 are comparative examples. In Comparative Example Nos. 1 to 3, the Sc content did not reach the lower limit of the present invention, and the reliability evaluation results were all "×". In addition, the inner quality of the metal wire after a high temperature and long time course was evaluated. As a result, the average grain size of Comparative Example Nos. 1 to 3 all exceeded 50 μm. It is presumed that the reason is that the Sc in the metal wire is insufficient, even after the aging heat treatment, the mechanical strength does not rise sufficiently, the recrystallization temperature does not rise sufficiently, and the recrystallization proceeds excessively during the high temperature and long time course. Furthermore, the total content of Y, La, etc. in Comparative Example No. 1 did not reach the lower limit of the present invention. Furthermore, the total content of Y, La, etc. in Comparative Example No. 3 exceeds the upper limit of the present invention, and the bondability and wafer cracks after bonding are "×".

In Comparative Example Nos. 4 and 5, the total content of Y, La, etc. did not reach the lower limit of the present invention. The reliability evaluation results are all "△". In addition, the inner quality of the metal wire after a long-term high temperature process was evaluated. As a result, the average grain size exceeded 50 μm. It is presumed that the reason is that the total content of Y, La, etc. in the metal wire is insufficient, and even after the aging heat treatment, the mechanical strength is not sufficiently increased, and the recrystallization temperature is not sufficiently increased, and it recrystallizes in the high temperature and long time course. Excessively proceed. In Comparative Example No. 6, the total content of Y, La, etc. exceeds the upper limit of the present invention. As a result, the Vickers hardness of the metal wire is out of the preferable range. In addition, the bondability and chip cracks after bonding are "×", and the reliability evaluation result is "×".

In Comparative Examples No. 7 to 9, the Sc content exceeds the upper limit of the present invention. Furthermore, in Comparative Example Nos. 7 and 8, the total content of Y, La, etc. did not reach the lower limit of the present invention, and in Comparative Example No. 10, the total content of Y, La, etc. exceeded the upper limit of the present invention. Since the Sc content of Comparative Example Nos. 7-10 all exceeded the upper limit of the present invention, the Vickers hardness exceeded the preferred upper limit of the present invention. If Sc exceeds the upper limit, even if it is forced to solid-solve, it will not completely solid-solve and precipitate, so the Vickers hardness is out of the range. In Comparative Example No. 10, since the total content of Y, La, etc. also exceeded the upper limit, the average crystal grain size did not reach the preferred lower limit of the present invention, and the <111> azimuthal area ratio exceeded the preferred upper limit of the present invention. If Sc, Y, La, etc. exceed the upper limit, they will not be completely dissolved and precipitated. Therefore, the particle size becomes smaller and the <111> orientation also increases. As a result, in Comparative Example Nos. 7 to 10, all of the bonding properties and chip cracks were "×", and the joint reliability evaluation results after the high-temperature long-term history were also "×".

Claims (5)

An Al bonding wire characterized in that it contains 0.01 to 1% Sc in mass%, and further contains at least one of Y, La, Ce, Pr, and Nd in a total of 0.01 to 0.1%, and the remainder contains Al and non- Avoid impurities. Such as the Al bonding wire of claim 1, wherein the average crystal grain size in the cross section perpendicular to the longitudinal direction of the metal wire is 0.1-50 μm. Such as the Al bonding wire of claim 1, wherein in the cross section perpendicular to the longitudinal direction of the metal wire, the area ratio of the crystal whose angle difference between the orientation of the crystal <111> and the longitudinal direction of the metal wire is within 15° is 30 to 90% . For example, the Al bonding wire of claim 1 has a Vickers hardness in the range of Hv20-40. The Al bonding wire according to any one of claims 1 to 4, wherein the diameter of the metal wire is 50-600 μm.