Aluminum connection material

Abstract

The present invention provides an Al connecting material that satisfies excellent temperature cycle reliability and good first bonding strength. The Al connecting material contains 4.0 mass % or more and 12.0 mass % or less of Si, and has a specific electrical resistivity Ra of 2.6×10 -8 Ωm or more 3.6×10 -8 Ωm or less, and when the crystal orientation of the Al phase in the L cross section (cross section in the central axis direction including the central axis) of the Al connecting material is measured, the angular difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> The total orientation ratio of the crystal orientation is 20% or more and 70% or less, and when the total orientation ratio is 25% or less, the angle difference with respect to the central axis direction is 15° or less. <110> An Al connector with a crystal orientation ratio of 5% or more.

Description

[Technical field]

[0001] The present invention relates to an Al connecting material. [Background technology]

[0002] In semiconductor devices, electrodes formed on a semiconductor chip are connected to electrodes on a lead frame or a substrate by bonding wires (wire material) or bonding ribbons (strip material). In power semiconductor devices, bonding wires and bonding ribbons made of aluminum (Al) are mainly used. The wire diameter of Al bonding wires is mainly in the range of 100 μm to 600 μm, and the width of Al bonding ribbons is mainly in the range of 100 μm to 3000 μm, and the thickness is mainly in the range of 50 μm to 600 μm. Here, Al bonding wires and Al bonding ribbons are collectively called Al connection materials.

[0003] In power semiconductor devices, silicon (Si) is often used as the material for the semiconductor chip, and Al-Si alloys or Al-Cu alloys are often used as the material for the electrodes formed on the semiconductor chip. Power semiconductor devices using Al connecting materials are often used as high-power devices such as air conditioners and solar power generation systems, and as semiconductor devices for vehicles.

[0004] There are two methods for joining Al connecting materials: the first joining with electrodes on a semiconductor chip, and the second joining with electrodes on a lead frame or substrate, both of which use wedge joining. Wedge joining is a method in which ultrasonic vibration and load are applied to the Al connecting material via a metal tool, destroying the surface oxide film on the Al connecting material and the electrode material, exposing the new surface, and performing solid-state diffusion bonding. This joining method is characterized by the fact that it connects the connecting material in a solid state without melting it, and is a joining technology that differs from welding technology, which melts the connecting material.

[0005] Next-generation power semiconductor devices are required to operate stably for a long period of time compared to general-purpose power semiconductor devices. Power semiconductor devices operate by repeatedly turning current on and off. When current is supplied to a Si semiconductor chip through an Al connecting material, the temperature of the first junction rises. On the other hand, when the current supply is stopped, the temperature of the first junction drops. In this way, the first junction repeatedly rises and falls in temperature during operation of the power semiconductor. As a result, thermal stress caused by the difference in thermal expansion between the Al connecting material and the semiconductor chip is repeatedly applied to the first junction. When a connecting material made only of high-purity Al is used, the Al connecting material breaks down in a relatively short time due to thermal stress, making it difficult to satisfy the performance required for next-generation power semiconductor devices. Therefore, next-generation power semiconductors are required to improve the junction life (hereinafter also referred to as "temperature cycle reliability") associated with the rise and fall of temperature of the first junction.

[0006] In response to the demand for temperature cycle reliability, Al bonding wires that focus on improving mechanical strength have been proposed. As a method for improving the mechanical properties of Al bonding wires, a method of adding specific elements to Al has been proposed.

[0007] Patent Document 1 discloses a bonding wire made of an Al alloy containing at least magnesium (Mg) and silicon (Si) and having a total content of Mg and Si of 0.03% by mass to 0.3% by mass. This patent document discloses that the decrease in the bonding strength of the first bonding part in a cold-temperature cycle test in the temperature range from 70°C to 120°C is delayed due to the effect of increasing the strength by solid solution strengthening of Mg and Si and the effect of suppressing crack growth by precipitated magnesium silicide (Mg2Si).

[0008] Patent Document 2 discloses a bonding wire made of an alloy containing 0.01-0.2 mass% iron (Fe), 1-20 mass ppm silicon (Si), and the remainder being Al with a purity of 99.997 mass% or more, in which the amount of Fe in solid solution is 0.01-0.06%, the amount of Fe precipitated is 7 times or less the amount of Fe in solid solution, and the wire has a fine structure with an average crystal grain size of 6-12 μm. This patent document discloses that the mechanical strength of the matrix is ​​improved by uniformly dispersing intermetallic compound particles of Fe and Al in Al, and the recrystallized grains are further refined, thereby suppressing a decrease in the bonding strength of the 1st bonding portion in a thermal shock test in a temperature range of -50°C to 200°C.

[0009] Patent Document 3 discloses a bonding wire obtained by melting an Al-Si alloy containing 0.1 to 5 mass% silicon (Si) with the remainder being Al and impurities, and then extruding and quenching the melted Al-Si alloy to form it into a thin wire. This patent document discloses that mechanical strength is improved by quenching the molten Al-Si alloy to finely and uniformly disperse Si. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2014-131010 A [Patent Document 2] JP 2014-129578 A [Patent Document 3] Japanese Patent Application Publication No. 59-57440 Summary of the Invention [Problem to be solved by the invention]

[0011] As described above, the next-generation power semiconductor device is required to be able to withstand longer use than the general-purpose power semiconductor device. During the operation of the power semiconductor device, the temperature of the first joint repeatedly rises and falls. As a result, since the Al connecting material has a larger linear expansion coefficient than the semiconductor chip, thermal stress occurs in the first joint due to the difference in linear expansion coefficient between the two, and the Al connecting material may eventually be fatigued. A temperature cycle test is one of the tests for accelerating evaluation of the life (temperature cycle reliability) of the joint associated with the rise and fall in temperature of the first joint. The Al connecting material used in the next-generation power semiconductor is required to exhibit excellent temperature cycle reliability in a temperature cycle test. However, when an Al connecting material with high strength due to the addition of Si or the like as disclosed in Patent Documents 1 to 3 is used, in a temperature cycle test assuming use in the next-generation power semiconductor device, it has been confirmed that there is a problem that cracks progress at a relatively high speed in the Al alloy electrode, which has a lower strength than the Al connecting material, and it is difficult to stably obtain good temperature cycle reliability.

[0012] Conventional temperature cycle tests (hereinafter, also referred to as "TCT") can be easily performed using commercially available test equipment. However, the rate of change of temperature in TCT is relatively slow, and there is concern that it may deviate from the fast rate of change of temperature during the operation of power semiconductor devices. Recently, therefore, in order to bring the temperature change rate closer to the conditions of actual use, high-speed temperature cycle tests (hereinafter, also referred to as "high-speed TCT"), which increase the temperature change rate, have been considered. The rate of change of temperature is, for example, about 10°C / min in conventional TCT, whereas in high-speed TCT, the temperature changes at a high speed of, for example, about 200°C / min. Regarding the reliability evaluation of the joints of Al connecting materials, even if the reliability of an Al connecting material does not decrease when evaluated by conventional TCT, there are cases where the joint strength decreases and the joint life is shortened when evaluated by high-speed TCT. Therefore, there is a demand for Al connecting materials that exhibit good joint reliability even in high-speed TCT, which is a more severe test that is closer to the conditions of actual use, and that provide excellent temperature cycle reliability. Hereinafter, the temperature cycle reliability in high-speed TCT may be referred to as "high-speed temperature cycle reliability".

[0013] In addition, if a bonding failure occurs during bonding, such as the peeling off of the Al connecting material from the electrode, this leads to product defects and a decrease in manufacturing yield, so it is required to obtain good bonding strength at each bonding part. In this regard, if ultrasonic vibration or load is applied strongly to the 1st bonding part in order to obtain good bonding strength, the semiconductor chip may be damaged. In particular, when an Al connecting material strengthened by adding Si or the like is used, the semiconductor chip is easily damaged during the 1st bonding due to its hardness, and when the ultrasonic vibration or load is adjusted to reduce such damage, the bonding area cannot be stably secured due to its high deformation resistance and instability of the deformation direction, so that sufficient bonding strength of the 1st bonding part (hereinafter, also simply referred to as "1st bonding strength") cannot be obtained in some cases. These problems at the initial bonding of the 1st bonding part eventually cause a decrease in temperature cycle reliability and instability, which is an obstacle to practical use of the Al connecting material strengthened by adding Si or the like.

[0014] An object of the present invention is to provide an Al connecting material that satisfies excellent temperature cycle reliability and good first bonding strength. [Means for solving the problem]

[0015] As a result of intensive research into the above-mentioned problem, the inventors have discovered that an Al connecting material containing 4.0 mass % or more and 12.0 mass % or less of Si has a specific electrical resistivity Ra within a specific range, and when the crystal orientation of the Al phase in an L cross section (a cross section in the direction of the central axis including the central axis) of the Al connecting material is measured, the angular difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> The inventors discovered that an Al connecting material in which the total orientation ratio of crystal orientations falls within a specific range can solve the above problems, and after further investigations based on this knowledge, they completed the present invention.

[0016] That is, the present invention includes the following. <1> An Al connecting material containing 4.0 mass% or more and 12.0 mass% or less of Si, Specific electrical resistivity Ra is 2.6×10 -8 Ωm or more 3.6×10 -8 Ωm or less, When the crystal orientation of the Al phase in the L cross section (cross section in the direction of the central axis including the central axis) of the Al connecting material is measured, the angular difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> The total orientation ratio of the crystal orientation is 20% or more and 70% or less, and when the total orientation ratio is 25% or less, the angle difference with respect to the central axis direction is 15° or less. <110> An Al connector with a crystal orientation ratio of 5% or more. <2> The crystal orientation of the Al phase in the L cross section has an angle difference of 15° or less with respect to the central axis direction. <110> The orientation ratio of the crystal orientation is 5% or more and 50% or less. <1> The Al connecting material described in <3> When the crystal orientation of the Si phase in the L cross section is measured, the angular difference with respect to the central axis is 15° or less. <111> Crystal orientation and <110> The total orientation ratio of the crystal orientation is 20% or more and 70% or less. <1> or <2> The Al connecting material described in <4> The average ratio (c / d) of the short side length c to the long side length d of the Al phase in the L cross section is 0.2 to 0.7. <1> ~ <3> The Al connecting material according to any one of the preceding claims. <5> Furthermore, it contains one or more of Sr, Na, Ca, and B in total in an amount of 5 mass ppm or more and 800 mass ppm or less. <1> ~ <4> The Al connecting material according to any one of the preceding claims. <6> Further, it contains one or more of Fe, Mg, P, and Ti in a total amount of 5 ppm by mass or more and 500 ppm by mass or less. <1> ~ <5> The Al connecting material according to any one of the preceding claims. <7> The total concentration of other elements in the Al connecting material is 0.5 mass% or less. <1> ~ <6> The Al connecting material according to any one of the preceding claims. Effect of the Invention

[0017] According to the present invention, it is possible to provide an Al connecting material that satisfies excellent temperature cycle reliability and good first bonding strength. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram for explaining a measurement surface (inspection surface) when measuring the crystal orientation and shape (shape ratio (c / d)) of the Al phase and the Si phase of an Al connecting material. The measurement surface is a cross section (L cross section) in the central axis direction including the central axis of the Al connecting material. [Diagram 2] FIG. 2 is a schematic diagram for explaining the short side length (c) and long side length (d) of the Al phase in the L cross section. [Diagram 3] FIG. 3 is a schematic diagram for explaining the hollow defect of the first bonded portion. [Figure 4] FIG. 4 shows an example of an internal crack in an Al connector observed with a soft X-ray transmission device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be described in detail below based on preferred embodiments. Although the drawings may be referred to in the description, each drawing merely shows the shape, size and arrangement of components to the extent that the invention can be understood. The present invention is not limited to the following embodiments and examples, and may be modified and implemented as desired within the scope of the claims of the present invention and their equivalents.

[0020] [Al connection material] The Al connecting material of the present invention is an Al connecting material containing 4.0 mass% or more and 12.0 mass% or less of Si, Specific electrical resistivity Ra is 2.6×10 -8 Ωm or more 3.6×10 -8 Ωm or less, When the crystal orientation of the Al phase in the L cross section (cross section in the direction of the central axis including the central axis) of the Al connecting material is measured, the angular difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> The total orientation ratio of the crystal orientation is 20% or more and 70% or less, and when the total orientation ratio is 25% or less, the angle difference with respect to the central axis direction is 15° or less. <110> It is characterized by having a crystal orientation ratio of 5% or more.

[0021] As mentioned above, in the temperature cycle test (TCT), when a connecting material made of only high-purity Al is used, cracks propagate relatively fast inside the connecting material, making it difficult to obtain good temperature cycle reliability. On the other hand, when an Al connecting material strengthened by adding Si or the like is used, cracks propagate inside the Al alloy electrode, which has a relatively low strength, so it was confirmed that it is difficult to obtain the temperature cycle reliability required for next-generation power semiconductor devices. That is, in a high-speed temperature cycle test (high-speed TCT) in which the temperature change rate is accelerated, which is close to the conditions of actual use, it was confirmed that even an Al connecting material whose reliability does not decrease when evaluated by the conventional TCT may experience a decrease in bonding strength and a shortened bonding life. Furthermore, when an Al connecting material strengthened by adding Si or the like is used, the semiconductor chip is easily damaged during the 1st bonding, and when the ultrasonic vibration or load is adjusted to reduce such damage, sufficient 1st bonding strength may not be obtained.

[0022] As a result of intensive research by the inventors to solve the above problems, it has been found that an Al connecting material contains 4.0 mass% or more and 12.0 mass% or less of Si, has a specific electrical resistivity Ra within a specific range, and when the crystal orientation of the Al phase in the L cross section is measured, the angular difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> It was found that an Al connecting material with a total orientation ratio of crystal orientations falling within a specific range exhibits good joint reliability even in high-speed TCT, a more severe test close to the conditions of actual use, and provides excellent temperature cycle reliability while improving the first joint strength. Such an Al connecting material of the present invention significantly contributes to realizing the temperature cycle reliability required for next-generation power semiconductor devices as well as good first joint strength.

[0023] The Al connecting material of the present invention contains 4.0 mass% to 12.0 mass% of Si, and is composed of an Al phase in which Si is dissolved in Al, and a Si phase formed by crystallization or precipitation of Si. Here, the Al phase may contain other additive elements in addition to Si. The Si phase is a general term for Si crystallized particles and Si precipitates. The Si crystallized particles are formed from the melt during solidification and are coarse with a size of about 1 to 20 μm, while the Si precipitates are formed from the solid state and are small with a size of about 0.1 to several μm.

[0024] In the present invention, the L cross section of the Al connection material, i.e., the cross section in the central axis direction including the central axis of the Al connection material, is as will be explained later in the section "(Method of measuring the orientation ratio of the crystal orientations of the Al phase and the Si phase)" with reference to Figure 1.

[0025] The reason why the Al connecting material of the present invention can provide excellent temperature cycle reliability and good first bonding strength is presumed to be as follows.

[0026] If the Si concentration is in the range of 4.0 mass% or more and 12.0 mass% or less, the Si crystallized matter tends to be generated in a particulate form. As described above, such Si crystallized matter grows relatively large, and contributes to the improvement of properties such as suppression of linear expansion and temperature cycle reliability. On the other hand, the Al connecting material containing a high concentration of Si becomes hard, and the deformation during joining may become insufficient or the deformation direction may become unstable, resulting in a decrease in the joining strength. These problems during initial joining may ultimately cause a decrease in temperature cycle reliability or instability, which is an obstacle to the practical use of Al connecting materials that have been strengthened by the addition of Si, etc.

[0027] The inventors have discovered that in order to improve the initial bonding strength while suppressing damage to the semiconductor chip when ultrasonic vibration and load are applied (hereinafter also referred to simply as "during bonding"), it is effective to simultaneously control (i) the Si and fine precipitates in the solid solution state in the Al phase and (ii) the orientation of a specific crystal orientation of the Al phase.

[0028] Regarding the above (i), since the Si atoms dissolved in the Al phase act to increase the deformation resistance during joining by increasing lattice distortion, pinning dislocations, etc., reducing the amount of Si in the solid solution state softens the Al connecting material and promotes its deformation. Also, a part of the dissolved Si precipitates by heat treatment to form fine Si precipitates, etc., and controlling the size of these precipitates to within the submicron range can improve uniform deformation during joining and the temperature cycle characteristics of the joint.

[0029] Here, since the solid solution state of Si cannot be directly observed, it is difficult to accurately measure the amount of solid solution in the entire Al connection material. Although fine Si precipitates can be partially observed by advanced analysis such as TEM, the observation area is limited, and it is difficult to accurately grasp the amount and volume of fine Si precipitates in the Al connection material, including the particle distribution. In this regard, the specific electrical resistance of the Al-Si alloy obtained by electrical measurement can be managed as an index of the amount of solid solution of Si in the Al phase, the amount and distribution of fine precipitates. Furthermore, it was found that controlling this specific electrical resistance is effective in changing the material structure of the Al connection material to improve the bondability. For example, reducing the specific electrical resistance is related to a decrease in the amount of solid solution of Si or an increase in the amount of fine precipitates, and contributes to the effect of reducing damage to semiconductor chips during bonding. Conversely, increasing the specific electrical resistance is related to an increase in the amount of solid solution of Si or a decrease in the amount of fine precipitates. The effect of coarsened Si crystallized precipitates on the specific electrical resistance is much smaller than that of solid solution Si, and is almost negligible.

[0030] Therefore, adjusting the material structure of the Al connecting material using the specific electrical resistance of the Al-Si alloy as an index leads to controlling the solid solution state of Si and fine Si precipitates, and is effective in achieving an improvement in the bonding strength while suppressing damage to the semiconductor chip during bonding. In addition, in conventional connecting materials made of Al alloys, the electrical conductivity (the reciprocal of the electrical resistance) has been adjusted, but this was from the viewpoint of electrical properties to make it easier to pass electricity. The optimization of the specific electrical resistance of the Al-Si alloy in the present invention is characterized in that it is set as an index for controlling the material structure of solid solution and fine precipitation, rather than for the purpose of adjusting the electrical properties. When controlling the material structure, there is an appropriate range for the specific electrical resistance, and if it deviates from that range, it is difficult to achieve an improvement in the bonding strength while suppressing damage to the semiconductor chip during bonding, even if the electrical properties are good. In addition, it was confirmed that there is a weak relationship between the specific electrical resistance and the bonding properties for Al connecting materials containing Si in a range of 3 mass% or less. It has been confirmed that the ability to control the specific electrical resistivity as an indicator for improving bonding strength while suppressing damage to the semiconductor chip during bonding is uniquely applicable to the configuration of the present invention, which contains 4.0 mass % or more and 12.0 mass % or less of Si.

[0031] Regarding the above (ii), controlling the texture of the Al phase crystal grains is effective in promoting sufficient deformation during joining. <110> Crystal orientation and <111> The total ratio of crystal orientations is in the range of 20% to 70% (however, when the total ratio of the orientations is 25% or less, the angle difference with respect to the central axis direction is 15° or less). <110> It is believed that if the crystal orientation ratio is 5% or more, the effect of promoting the deformation of the entire Al connecting material and increasing the joint strength can be obtained. <110> Crystal orientation and <111> It is believed that by controlling the orientation ratio of the crystal orientations, the effect of destroying the oxide film present at the bonding interface during bonding and exposing a new surface, thereby promoting metal bonding, is enhanced. <110> The crystal orientation mainly controls the deformation of the Al connector parallel to the ultrasonic vibration. <111> It is believed that the orientation of the crystal orientation mainly controls the deformation in the direction perpendicular to the ultrasonic vibration (the width direction of the Al connecting material).

[0032] As described above, it is presumed that the Al connecting material of the present invention can provide excellent temperature cycle reliability and good 1st bond strength as a result of appropriately controlling the factors that contribute to improving temperature cycle reliability and 1st bond strength, as described above.

[0033] -Si concentration- The Si concentration in the range of 4.0 mass% or more and 12.0 mass% or less reduces the thermal distortion of the joint and helps to improve the temperature cycle characteristics. If it is less than 4.0 mass%, the improvement effect is small, and if it exceeds 12.0 mass%, problems such as a decrease in initial joint strength due to hardening and damage to the semiconductor chip occur. From the viewpoint of obtaining good temperature cycle reliability even in a high-speed TCT with a high temperature change rate close to the conditions of actual use, the concentration of Si in the Al connecting material of the present invention is 4.0 mass% or more, preferably 4.5 mass% or more, more preferably 4.6 mass% or more, 4.8 mass% or more, 5.0 mass% or more, 5.2 mass% or more, 5.4 mass% or more, or 5.5 mass% or more. On the other hand, if the hardness of the Al connecting material is excessive, damage to the semiconductor chip is likely to occur during 1st joining under the joining conditions of ultrasonic vibration and load that are generally used. From the viewpoint of obtaining good bonding strength when performing 1st bonding under general bonding conditions, the Si concentration in the Al connecting material of the present invention is 12.0 mass% or less, preferably 11.5 mass% or less or 11.0 mass% or less, and more preferably 10.8 mass% or less, 10.6 mass% or less, 10.5 mass% or less, 10.4 mass% or less, 10.2 mass% or less, or 10.0 mass% or less.

[0034] For example, an ICP (Inductively Coupled Plasma) emission spectrometer or an ICP mass spectrometer can be used to analyze the concentration of elements contained in the Al connecting material of the present invention. If elements derived from atmospheric contaminants such as oxygen and carbon are adsorbed on the surface of the Al connecting material, it is effective to wash the surface with an acid or alkali according to the adsorbed substance before analysis.

[0035] -Specific electrical resistivity- In order to obtain good temperature cycle reliability even in high-speed TCT and good 1st joint strength, the specific electrical resistance of the Al joint material is set to 2.6×10 -8 Ωm or more, preferably 2.7×10 -8 Ωm or more, preferably 2.8×10 -8 The upper limit of the specific electrical resistivity is 3.6×10 -8 Ωm or less, preferably 3.5×10 -8 Ωm or less, more preferably 3.4×10 -8 It is less than Ωm.

[0036] The specific electrical resistance of the Al connecting material can be measured by a DC four-terminal measurement method. For example, a resistance meter DM7275 manufactured by Hioki E.E. Corporation can be used to measure the electrical resistance of the sample at room temperature with a sample length of 200 mm and a measurement current in the range of 0.02 to 0.1 mA. The measurement is performed five times, and the electrical resistance value R of each sample is calculated by the arithmetic average. If the electrical resistance value is R, the length of the sample is L, and the cross-sectional area of ​​the sample is S, the specific electrical resistance value M of the Al connecting material can be calculated by R × (S / L).

[0037] -Crystal orientation of Al phase in L section- In order to obtain good temperature cycle reliability even in high-speed TCT and good 1st joint strength, when the crystal orientation of the Al phase in the L cross section of the Al joint material is measured, the angle difference with respect to the central axis is 15° or less. <110> Crystal orientation and <111> The total orientation ratio of the crystal orientation (hereinafter, "Al phase <110> + <111> The ratio of the Al phase to the total of the Al phase is 20% or more, preferably 22% or more, 24% or more, 25% or more, or more than 25%, more preferably 26% or more or 28% or more, even more preferably 30% or more, and even more preferably 35% or more, 40% or more, 42% or more, 44% or more, or 45% or more. <111> + <110> When the total ratio is low, it has been confirmed that the effect of improving the temperature cycle reliability and the first bonding strength can be obtained even when the total ratio is in the range of 20% or more and less than 30%. <111> + <110> When the total ratio is 25% or less, the angle difference with respect to the central axis direction is 15° or less. <110> It has been confirmed that it is important that the orientation ratio of the crystal orientation is 5% or more. <110> + <111> The upper limit of the total ratio is 70% or less, preferably 65% ​​or less, more preferably 60% or less, and even more preferably 58% or less, 56% or less, or 55% or less, from the viewpoint of obtaining excellent temperature cycle reliability and good first bonding strength.

[0038] From the viewpoint of obtaining better 1st joint strength and suppressing hollowing of the 1st joint (phenomenon in which a part where the metal joint is insufficient is formed in the joint area between the Al joint material and the electrode), when the crystal orientation of the Al phase in the L cross section of the Al joint material is measured, the angular difference with respect to the central axis direction is 15° or less. <110> The orientation ratio of the crystal orientation (hereinafter, “Al phase <110> The ratio of the Al phase to the Al phase is preferably in the range of 5% to 50%. <110> + <111> The total ratio is in the range of 20% to 70%. <110> By setting the ratio to 5% or more and 50% or less, it is possible to obtain a high effect of suppressing the hollowing out of the first joint and improving the strength of the first joint. <110> The reason why the above effect is obtained when the ratio is in this range is presumed to be as follows. <110> When the ratio is in this range, it is believed that the deformation of the Al connecting material in the ultrasonic vibration direction can be promoted, and the 1st joint strength can be further improved. In addition, since hollow holes often occur in the ultrasonic vibration direction, it is believed that hollow holes can also be suppressed by promoting the deformation of the Al connecting material in the ultrasonic vibration direction as described above. <110> The ratio is more preferably 10% or more, further preferably 12% or more, 14% or more, or 15% or more, from the viewpoint of obtaining a better first joint strength and suppressing hollowing out of the first joint portion. <110> The upper limit of the ratio is more preferably 45% or less, further preferably 40% or less, 38% or less, 36% or less, or 35% or less.

[0039] To measure the orientation ratio of the crystal orientation of the Al phase in the L-section of the Al joint material, a method can be used that combines the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by electron backscatter diffraction (EBSD). In detail, in the measurement area where the L-section of the Al joint material is used as the inspection surface, the concentration measurement of Al and Si using EDS and the crystal orientation analysis using EBSD are performed simultaneously. Next, the Al phase and the Si phase are separated and extracted from the EDS measurement results using the analysis software attached to the device. Specifically, it is preferable to use the Chi Scan function, which is a function of the analysis software OIM Data Collection or OIM Anaysis (both made by TSL Solutions) attached to the FE-SEM device. Then, for the area identified as the Al phase, the analysis software attached to the device is used to determine the location of the Al phase. <110> Crystal orientation and <111> The orientation ratio of the crystal orientations and their total can be calculated. In calculating the orientation ratio, a partial ratio is used, which is calculated as a population of the area of ​​only the crystal orientations that can be identified based on a certain reliability within the measurement area. <110> Crystal orientation and <111> The area ratio of each crystal orientation is <110> Orientation ratio of crystal orientation, <111> Therefore, in one embodiment, the orientation ratio of the crystal orientation of the Al phase in the L cross section of the Al connecting material of the present invention is calculated by the following procedures (1) to (3). (1) In the measurement area where the L-section of the Al joint material is used as the inspection surface, the Al and Si concentrations are measured using EDS and the crystal orientation is measured using EBSD simultaneously. (2) Use the Chi Scan function to separate and extract Al and Si. Specifically, by setting a Tolerance equivalent to the Si threshold from the Si EDS measurement results, Al and Si can be separated and identified. The crystal orientation can be analyzed using the Al and Si crystal information from the material file. (3) The crystal orientation of the region identified as the Al phase was analyzed, and the Al phase <110> The orientation ratio of the crystal orientation and <111> The orientation ratio of the crystal orientation is calculated.

[0040] In step (2) above, the Tolerance (%) setting can be selected in the range of 20 to 40%, and in standard analysis of the L cross section of Al connecting material, it is preferable to compare at about 30%. Here is a supplementary explanation of the procedure for adjusting this Tolerance. It is preferable to select or confirm the Tolerance value so that the shape and size of the Si phase extracted and identified by the Chi Scan function are equivalent to those of the Si phase identified from the EDS map that displays the Si element concentration in EDS analysis in two dimensions.

[0041] In the present invention, the Al phase in the L cross section <110> The orientation ratio of the crystal orientation and <111> The orientation ratio of the crystal orientation was determined as the average value of the orientation ratios obtained by measuring three or more locations. In selecting the measurement area, it is preferable to obtain measurement samples from the Al connection material to be measured at intervals of 50 cm or more in the central axis direction of the Al connection material from the viewpoint of ensuring the objectivity of the measurement data, and provide them for measurement. In the present invention, the measurement area of ​​the crystal orientation by the EBSD method is preferably such that the length in the central axis direction of the Al connection material is 300 μm or more and less than 800 μm, and the entire Al connection material is included in the direction perpendicular to the central axis of the Al connection material, but if the size is large and it is difficult to measure the entire Al connection material, it may be adjusted to a range of less than 600 μm.

[0042] -Crystal orientation of the Si phase in the L cross section- From the viewpoint of obtaining better temperature cycle reliability in high-speed TCT, when the crystal orientation of the Si phase in the L cross section of the Al joint material is measured, the angle difference with respect to the central axis is 15° or less. <111> Crystal orientation and <110> The total orientation ratio of the crystal orientation (hereinafter, "Si phase <111> + <110> The ratio of the specific electric resistance to the Al phase is preferably in the range of 20% to 70%. <110> + <111> In addition to controlling the total ratio, the Si phase <111> + <110> If the total ratio is within this range, the strength retention rate that suppresses the decrease in the bonding strength can be improved, or the number of tests until the occurrence of a defect that reduces the bonding strength can be extended, thereby achieving even better temperature cycle reliability even in high-speed TCT. This is because of the Si phase <111> Crystal orientation and <110> Crystal orientation and Al phase <110> Crystal orientation and <111> It is believed that the alignment of the crystal orientation improves the adhesion of the interface between the Si phase and the Al phase, and this suppresses the peeling of the interface even when the number of cycles increases during high-speed TCT, which has a rapid temperature change rate. <111> + <110> The total ratio is more preferably 25% or more, further preferably 26% or more, 28% or more, or 30% or more. <111> + <110> From the viewpoint of obtaining excellent temperature cycle reliability and good first bonding strength, the total ratio is more preferably 65% ​​or less, and even more preferably 60% or less, 58% or less, 56% or less, 55% or less, 54% or less, 52% or less, or 50% or less.

[0043] To measure the orientation ratio of the crystal orientation of the Si phase in the L cross section of the Al joint material, a method can be used that combines the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by EBSD, just like in the measurement of the orientation ratio of the crystal orientation of the Al phase. The detailed procedure can be the same as that described above in relation to the measurement of the orientation ratio of the crystal orientation of the Al phase. In other words, for the area identified as the Si phase, the analysis software attached to the device can be used to determine the orientation ratio of the Si phase. <111> Crystal orientation and <110> The orientation ratio of the crystal orientations and their total can be calculated. In calculating the orientation ratio, a partial ratio is used, which is calculated as a population of the area of ​​only the crystal orientations that can be identified based on a certain reliability within the measurement area. Therefore, in one embodiment, the orientation ratio of the crystal orientations of the Si phase in the L cross section of the Al connecting material of the present invention is calculated by the following steps (1) to (3). (1) In the measurement area where the L-section of the Al joint material is used as the inspection surface, the Al and Si concentrations are measured using EDS and the crystal orientation is analyzed using EBSD simultaneously. (2) Using the Chi Scan function, Al and Si are separated and analyzed. Specifically, by setting a Tolerance equivalent to the Si threshold from the Si EDS measurement results, Al and Si can be separated and identified. The crystal orientation is analyzed using the Al and Si crystal information from the material file. (3) The crystal orientation of the region identified as the Si phase was analyzed, and the Si phase <111> The orientation ratio of the crystal orientation and <110> The orientation ratio of the crystal orientation is calculated.

[0044] In the present invention, the Si phase in the L cross section <111> The orientation ratio of the crystal orientation and <110> The orientation ratio of the crystal orientation was determined as the arithmetic mean value of the orientation ratio values ​​obtained by measuring at least three locations. The tolerance setting range in the above step (2), the method of obtaining the sample for measurement, and the measurement area of ​​the crystal orientation by the EBSD method are as described above for the measurement of the orientation ratio of the crystal orientation of the Al phase.

[0045] -Shape of Al phase in L cross section- When joining Al connectors by applying ultrasonic vibration and load, it is important to control the joint shape. The joint shape of an Al connector can be evaluated by the indentation width (joint width) in the direction perpendicular to the central axis of the Al connector at the fractured part when a shear strength test is conducted on the joint. Reducing and stabilizing the variation in this joint width will contribute to improving the reliability of temperature cycles. In this regard, there is concern that Al connectors that have been strengthened by adding Si, etc., will have greater variation in joint width compared to conventional Al connectors due to their high deformation resistance and instability in the deformation direction.

[0046] The inventors have discovered a material containing 4.0 mass % or more and 12.0 mass % or less of Si, having a specific electrical resistivity within a specific range, and <110> + <111> In the process of investigating Al connecting materials with a total ratio in a specific range, it was found that the shape of the Al phase in the L cross section affects the variation in the joint width when the Al connecting material is joined. In detail, it was found that the variation in the joint width when joined is reduced when the average value of the ratio (c / d) of the short side length c to the long side length d of the Al phase in the L cross section is in the range of 0.2 to 0.7. The value of this ratio (c / d) is an index showing the flatness. Further explanation will be given with reference to FIG. 2. FIG. 2 is a schematic diagram showing the Al phase in the L cross section of the Al connecting material, and the central axis direction of the Al connecting material is shown to correspond to the horizontal direction (left-right direction) in FIG. 2, and the direction perpendicular to the central axis is shown to correspond to the vertical direction (up-down direction) in FIG. 2. For the Al phase in the L cross section, the above-mentioned "short side length c" corresponds to the dimension indicated by the symbol c in FIG. 2. Also, for the Al phase in the L cross section, the above-mentioned "long side length d" corresponds to the dimension indicated by the symbol d in FIG. 2. Hereinafter, the ratio (c / d) of the short side length c to the long side length d of the Al phase in the L cross section will be simply referred to as the "Al phase shape ratio (c / d)." The value of the Al phase shape ratio (c / d) can be obtained by the Grain Shape Aspect Ratio in the analysis software provided with the device.

[0047] The reason why the variation in the bonding width during bonding can be reduced by controlling the average value of the shape ratio (c / d) of the Al phase in the Al connecting material of the present invention is presumed to be as follows. If the Al phase is long, such as columnar or fibrous, the deformation of the Al connecting material becomes non-uniform when ultrasonic vibration and load are applied, causing the bonding width to vary. As described above, in addition to achieving a state in which deformation is promoted by optimizing the specific electrical resistivity and controlling the material structure of solid solution and fine precipitation, it is believed that optimizing the shape ratio (c / d) of the Al phase acts to uniformize the directionality of deformation, friction, and bonding, stabilizing the bonding width. Since the Al connection material is manufactured by processing such as extrusion and wire drawing, the Al phase basically tends to be flattened in the central axis direction of the Al connection material, that is, the Al phase tends to be arranged so that the direction of the long side length d is the central axis direction of the Al connection material or a direction close to it, and as described above, the complex deformation in the direction parallel / perpendicular to the ultrasonic vibration is controlled by optimizing the crystal orientation of the Al phase, so it is considered that the desired effect can be achieved by managing the shape ratio (c / d) of the Al phase without specifying the direction. In order to reduce the variation in the joining width during joining, it is sufficient that the average value of the shape ratio (c / d) of the Al phase in the L cross section is within the above-mentioned preferable range, and it is not necessary for the shape ratio (c / d) of all the Al phases to be in the range of 0.2 to 0.7. For example, the Al phase may have an Al phase with a shape ratio (c / d) of less than 0.2, or may have an Al phase with a shape ratio (c / d) of more than 0.7.

[0048] From the viewpoint of reducing the variation in the joining width during joining and better achieving the temperature cycle reliability required for next-generation power semiconductor devices, the average value of the shape ratio (c / d) of the Al phase in the L cross section of the Al connecting material of the present invention is more preferably 0.25 or more, and its upper limit is more preferably 0.65 or less.

[0049] A method for measuring the shape ratio (c / d) of the Al phase in the L cross section of the Al connecting material will be described. First, as in the above-mentioned measurement of crystal orientation, a method can be used in which information on the Al concentration and Si concentration obtained by SEM-EDS is combined with information on the crystal orientation obtained by EBSD. The detailed procedure may be the same as that described above in relation to the measurement of the orientation ratio of the crystal orientation, that is, the crystal orientation can be analyzed by using the analysis software attached to the device for the area specified as the Al phase. If the orientation difference between the measurement points is 15° or more, it is determined to be a grain boundary and the shape ratio (c / d) is calculated. The average value of the shape ratio (c / d) of each Al phase is defined as the average value of the shape ratio (c / d) of the Al phase. In the process of calculating the shape ratio (c / d) of the Al phase, the parts where the crystal orientation cannot be measured or the parts where the crystal orientation can be measured but the reliability of the orientation analysis is low are excluded from the calculation. Therefore, in one embodiment, the average value of the shape ratio (c / d) of the Al phase in the L cross section of the Al connecting material of the present invention is calculated by the following procedures (1) to (3). (1) The L-section of the Al joint material is used as the inspection surface, and the Al and Si concentrations are measured using EDS and the crystal orientation is measured using EBSD simultaneously. (2) Use the Chi Scan function to separate and extract Al and Si. Specifically, by setting a Tolerance equivalent to the Si threshold from the Si EDS measurement results, Al and Si can be separated and identified. The crystal orientation can be analyzed using the Al and Si crystal information from the material file. (3) For the region identified as Al phase, the crystal orientation is analyzed, and if the orientation difference between the measurement points is 15° or more, it is determined to be a grain boundary, and the shape ratio (c / d) of each grain is obtained. The shape ratios (c / d) of each grain are averaged to calculate the average shape ratio (c / d) of the Al phase. Here, the average value of the shape ratio (c / d) of the Al phase is the value of the Grain Shape Aspect Ratio (hereinafter referred to as the "grain shape aspect ratio") of the analysis software. This value is obtained by averaging the grain shape aspect ratios of each grain. The grain shape aspect ratio is calculated by the ratio (c / d) of the short side length (c) (Grain Shape Minor Axis) and the long side length (d) (Grain Shape Major Axis) of one grain. In addition, for the average calculation, the average value obtained by the Area Average, which can be selected in the software attached to the device, is used. By adopting the average value found by area averaging, it is possible to accurately measure and judge whether the conditions related to the average value of the shape ratio (c / d) of the Al phase, which is suitable for reducing the variation in the bonding width during bonding, are met. The area average is calculated by averaging the values ​​obtained by multiplying the ratio of each particle area to the total particle area by each particle area value, and is calculated automatically by the software.

[0050] When measuring the average value of the shape ratio (c / d) of the Al phase in the L cross section, the setting range of Tolerance in the procedure (2) above and the measurement area of ​​the crystal orientation by the EBSD method are as described above for the measurement of the orientation ratio of the crystal orientation of the Al phase.

[0051] In addition to the above, there are several other methods for measuring the shape ratio (c / d) of the Al phase, including binarization processing from the observed image of the L cross section. However, in the present invention, a method is used that combines the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by EBSD, as described above, for the following reasons: the system is equipped with many measurement functions and can determine multiple characteristics such as the above-mentioned crystal orientation and the shape ratio (c / d) of the Al phase in a single measurement; automatic analysis is possible; and the measurement is easy using widely used equipment and analysis techniques.

[0052] -Addition of Sr, Na, Ca, and B- The Al connecting material of the present invention may further contain at least one of Sr, Na, Ca and B (hereinafter also referred to as the "first element group") in a total amount of 5 ppm by mass or more and 800 ppm by mass or less.

[0053] It was found that in Al connectors that have been strengthened by adding Si, etc., cracks (internal cracks) may occur within the Al connector during wire drawing. This is thought to be due to the formation of coarse Si crystals and non-uniform plastic deformation of the Al phase. Since internal cracks can lead to defects such as reduced temperature cycle reliability and melting fracture when a large current is applied, it is necessary to suppress the occurrence of internal cracks.

[0054] Even if the Si content is 4.0 mass% or more and 12.0 mass% or less, the occurrence of internal cracks during processing can be suppressed by further containing at least one of Sr, Na, Ca, and B in a total amount of 5 mass ppm or more and 800 mass ppm or less. It is believed that adding the first element group at a total concentration of 5 mass ppm or more and 800 mass ppm or less will make the Si crystallized particles fine and disperse uniformly in the Al connecting material, thereby suppressing the occurrence of crack starting points. Furthermore, it is believed that adjusting the amount of Si solid solution in the Al phase by controlling the specific electrical resistance has the effect of mitigating processing strain in the Al phase and suppressing the growth of cracks.

[0055] From the viewpoint of suppressing the occurrence of internal cracks during processing, the total concentration of the first element group in the Al connecting material of the present invention is more preferably 20 ppm by mass or more, even more preferably 30 ppm by mass or more, 40 ppm by mass or more, or 50 ppm by mass or more, and the upper limit is preferably 750 ppm by mass or less, more preferably 740 ppm by mass or less, 720 ppm by mass or less, or 700 ppm by mass or less, from the viewpoint of easily achieving good 1st bonding strength while suppressing damage to the semiconductor chip.

[0056] -Addition of Fe, Mg, P, and Ti- The Al connecting material of the present invention may further contain at least one of Fe, Mg, P and Ti (hereinafter also referred to as "second element group") in a total amount of 5 ppm by mass or more and 500 ppm by mass or less.

[0057] Furthermore, by containing at least one of Fe, Mg, P, and Ti in a total amount of 5 mass ppm to 500 mass ppm, the occurrence of scratches and chipping on the surface of the Al connecting material can be suppressed, and a smooth surface can be formed. In an Al alloy containing Si at a high concentration of 4.0 mass % to 12.0 mass %, the surface hardens, and the Si phase and Al oxide present on the surface fall off, resulting in an Al connecting material with large surface irregularities, which can be scratched and chipped during wire drawing. It is presumed that the addition of the second element group stabilizes the Al oxide on the surface of the Al connecting material, refines the structure of the Al crystal grains, and hardens it, thereby reducing scratches and chipping during wire drawing. It is considered that the effect of suppressing scratches and chipping on the surface of the Al connecting material and forming a smooth surface can be enhanced by controlling the orientation ratio of the crystal orientation of the Al phase in the L cross section and adding the second element group.

[0058] From the viewpoint of forming an Al connecting material having a smooth surface while suppressing the occurrence of scratches and chipping on the surface, the total concentration of the second element group in the Al connecting material of the present invention is more preferably 10 ppm by mass or more, even more preferably 20 ppm by mass or more, 30 ppm by mass or more, 40 ppm by mass or more, or 50 ppm by mass or more, and the upper limit is preferably 450 ppm by mass or less, more preferably 440 ppm by mass or less, 420 ppm by mass or less, or 400 ppm by mass or less, from the viewpoint of easily achieving good 1st bonding strength while suppressing damage to the semiconductor chip.

[0059] When manufacturing the Al connecting material of the present invention, it is preferable to use Al with a purity of 4N (Al: 99.99% by mass or more) as the aluminum raw material, and it is even more preferable to use Al with a purity of 5N (Al: 99.999% by mass or more) or more, which has a lower amount of impurities.

[0060] The Al connecting material of the present invention may further contain elements other than Al, Si, the first element group, and the second element group (hereinafter, also referred to as "other elements"). The total concentration of the other elements in the Al connecting material is not particularly limited as long as the effects of the present invention are not impaired. The total concentration of the other elements may be, for example, 0.5 mass% or less, 0.4 mass% or less, 0.3 mass% or less, 0.2 mass% or less, 0.15 mass% or less, 0.1 mass% or less, 0.08 mass% or less, 0.06 mass% or less, 0.05 mass% or less, 0.04 mass% or less, 0.03 mass% or less, 0.025 mass% or less, 0.02 mass% or less, 0.018 mass% or less, 0.016 mass% or less, 0.015 mass% or less, 0.014 mass% or less, 0.012 mass% or less, or 0.01 mass% or less. The lower limit of the total concentration of the other elements is not particularly limited, and may be 0 mass%. In one embodiment, the remainder of the Al connecting material of the present invention is composed of Al and other elements. Therefore, in a preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, and other elements. In another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the first element group, and other elements. In yet another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the second element group, and other elements. In yet another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the first element group, one or more elements of the second element group, and other elements.

[0061] In one embodiment, the balance of the Al connecting material of the present invention is composed of Al and inevitable impurities. Therefore, in a preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, and inevitable impurities. In another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the first element group, and inevitable impurities. In yet another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the second element group, and inevitable impurities. In yet another preferred embodiment, the Al connecting material of the present invention is composed of Al, Si, one or more elements of the first element group, one or more elements of the second element group, and inevitable impurities.

[0062] In a preferred embodiment, the Al connecting material of the present invention does not have a coating mainly composed of a metal other than Al on the outer periphery of the Al connecting material. Here, the "coating mainly composed of a metal other than Al" refers to a coating in which the content of a metal other than Al is 50 mass % or more.

[0063] The Al connecting material of the present invention may be an Al bonding wire or an Al bonding ribbon. When the Al connecting material of the present invention is an Al bonding wire, its wire diameter is not particularly limited, and may be, for example, in the range of 100 to 600 μm. When the Al connecting material of the present invention is an Al bonding ribbon, its rectangular or approximately rectangular cross-sectional dimensions (W×T) are not particularly limited, and, for example, W may be 100 to 3000 μm, and T may be 50 to 600 μm.

[0064] The Al connecting material of the present invention can provide excellent temperature cycle reliability and good first bonding strength, and therefore can be suitably used as an Al connecting material for semiconductor devices, particularly as an Al connecting material for power semiconductor devices.

[0065] -Method of manufacturing Al connection material- An example of a method for producing an Al connecting material of the present invention will be described below. Hereinafter, an example will be described in conjunction with the production of an Al bonding wire having a wire diameter of 200 to 400 μm.

[0066] The Al and alloying elements used as raw materials are preferably of high purity. The purity of Al is preferably 99.99% by mass or more, with the remainder being composed of inevitable impurities. The purity of Si, the first element group, and the second element group used as alloying elements is preferably 99.9% by mass or more, with the remainder being composed of inevitable impurities. The Al alloy used for the bonding wire can be produced by loading the Al raw material and the raw material of the alloying elements into a graphite or alumina crucible processed to obtain a cylindrical ingot, and melting it using an electric furnace or a high-frequency heating furnace. The diameter of the cylindrical ingot is preferably Φ6 mm or more and less than 8 mm, taking into consideration the workability in the subsequent processing steps. The atmosphere in the furnace during melting is preferably an inert atmosphere or a reducing atmosphere to prevent excessive oxidation of Al and other elements constituting the wire. The maximum temperature of the molten metal during melting is preferably in the range of 800 ° C or more and less than 1050 ° C, taking into consideration the ease of controlling the shape and size of the Si phase during solidification while ensuring the fluidity of the molten metal. The cooling method after melting can be water cooling, furnace cooling, air cooling, or the like.

[0067] The cylindrical ingot obtained by melting is subjected to solution treatment by heating at high temperature, and then repeatedly subjected to wire drawing using a die to produce wire of the desired diameter. The wire after wire drawing can be used as Al alloy bonding wire by performing final heat treatment in an electric furnace.

[0068] In order to control the crystal orientation and grain size of the Si phase in the L cross section, it is effective to control the heat treatment conditions such as solution treatment, homogenization treatment, and final heat treatment, as well as the wire drawing conditions, etc. During the wire drawing process, it is effective to use a lubricant to ensure lubrication at the contact interface between the wire and the die.

[0069] Specific electrical resistivity of 2.6×10 -8 Ωm or more 3.6×10 -8 An example of the manufacturing conditions for controlling the resistance to a range of Ωm or less is shown below.

[0070] To adjust the specific electrical resistivity, it is effective to control the amount of Si solid solution in the Al phase and the amount and distribution of fine precipitates. Specifically, it is effective to subject the ingot to a two-stage heat treatment and control the conditions of the final heat treatment.

[0071] In the two-stage heat treatment, it is preferable to perform a solution treatment at a high temperature, and then perform a homogenization treatment continuously during the cooling process. It is effective to perform the solution treatment at a temperature range of 400°C or higher and lower than 550°C for a period of 1 hour or higher and lower than 6 hours. It is effective to perform the homogenization treatment after the solution treatment at a temperature range of 250°C or higher and lower than 350°C for a period of 2 hours or higher and lower than 6 hours. The solution treatment at a high temperature promotes the solid solution of Si, and the heat treatment time can be adjusted to further dissolve a part of the crystallized Si phase. In addition, the homogenization treatment during cooling can be controlled by precipitating a part of the excessively dissolved Si to form fine Si precipitates, or by growing a part of the Si crystallized phase. For example, if the solution treatment is performed at a high temperature of 500°C to increase the amount of dissolved Si, and then the homogenization treatment is performed at 300°C, the specific electrical resistivity tends to decrease.

[0072] Furthermore, in order to finely adjust the specific electric resistance, it is effective to set the temperature range of the final heat treatment to 250°C or more and less than 350°C, and the time to 2 hours or more and less than 24 hours. By processing the ingot that has been subjected to the above two heat treatments to form a state in which the Si phase is distributed almost uniformly and then performing the final heat treatment, it is possible to uniformly control the concentration of Si dissolved in the Al phase. As a result, it becomes easy to control the specific electric resistance. For example, if the final heat treatment is performed at a low temperature for a long period of time, the specific electric resistance tends to decrease.

[0073] Al phase in L section <110> + <111> In order to adjust the total ratio to the range of 20% to 70%, it is effective to control the final heat treatment conditions.

[0074] Al phase <110> + <111> In adjusting the total ratio to the desired range, it is preferable to adjust the temperature range of the final heat treatment to 250°C or higher and lower than 350°C, and the time range to 2 hours or higher and lower than 24 hours. The final heat treatment advances the recovery and recrystallization of the Al phase, and at the same time, the amount of Si solid solution in the Al phase changes depending on the heat treatment temperature, causing the recrystallization temperature to change. In addition to the formation of the above-mentioned processed texture, by adjusting the progress of recrystallization by the final heat treatment, it becomes easy to control the orientation of the crystal orientation. For example, by adjusting the temperature or time of the final heat treatment, a dense alloy can be obtained. <110> Crystal orientation and <111> The orientation ratio of the crystal orientations tends to increase.

[0075] Al phase in L section <110> In order to adjust the ratio to within the range of 5% to 40%, it is effective to control the wire feed speed (wiredrawing speed) in the wiredrawing process and the final heat treatment conditions.

[0076] Al phase <110> In order to control the ratio, it is effective to control the wire feed speed according to the wire diameter to be drawn. The process of drawing the wire from the wire diameter of the ingot obtained by melting to 1 / 5 of the wire diameter is called "wire drawing 1", and the process of drawing the wire from 1 / 5 of the wire diameter to the final wire diameter is called "wire drawing 2". It is preferable that the wire feed speed in wire drawing 1 is 10 m / min or more and less than 25 m / min, and the wire feed speed in wire drawing 2 is 30 m / min or more and less than 50 m / min. Furthermore, it is preferable to adjust the temperature range of the final heat treatment to 270°C or more and less than 330°C, and the time to 10 hours or more and less than 24 hours. This is because by setting the wire feed speed in a predetermined range, the stress applied in the direction of the central axis of the wire during wire drawing can be adjusted, and by setting the final heat treatment conditions in a predetermined range, the rotation of the crystal orientation can be promoted, thereby regulating the formation of the Al phase. <110> The ratio is easily controlled.

[0077] In order to adjust the crystal orientation of the Si phase, it is effective to subject the ingot to two-stage heat treatment as described above and to control the area reduction rate during wire drawing.

[0078] By adjusting the conditions of the two-stage heat treatment as described above, the division and growth of the Si phase that crystallizes during the solidification process is promoted, and the crystal orientation of the Si phase is improved. <111> and <110> The orientation of the molecules can be promoted.

[0079] Regarding the wire drawing conditions, it is effective to set the wire area reduction rate per die used during wire drawing to be in the range of 12% or more and less than 30%. Here, if the wire area reduction rate per die is P1, P1 is expressed by the following formula.

[0080] P1 = {(R2 2 -R1 2 ) / R2 2}×100 In the formula, R2 represents the diameter (mm) of the wire before processing, and R1 represents the diameter (mm) of the wire after processing.

[0081] By adjusting the wire area reduction rate within the above range, the entire wire is significantly deformed during die processing, and processing strain increases even inside the wire, so that the Si phase is aligned in the direction of the wire's central axis, while at the same time, processing strain within the Si phase is adjusted. From this state of wire drawing, by carrying out subsequent heat treatment, a high atomic density is obtained. <111> Crystal orientation and <110> The orientation ratio of the crystal orientation can be increased, and the Si phase has a high elastic modulus. <111> Crystal orientation and <110> It is possible to increase the orientation ratio of the crystal orientation.

[0082] In order to adjust the shape (shape ratio (c / d)) of the Al phase in the L cross section, it is effective to control the intermediate heat treatment and the final heat treatment.

[0083] Intermediate heat treatment is a heat treatment performed in the middle of the process of processing from an ingot to a wire of the final wire diameter. The temperature range of intermediate heat treatment is effectively 300°C or higher and lower than 450°C, and the time is 30 minutes or more and less than 3 hours. Intermediate heat treatment is effectively performed with a wire diameter 2.5 to 4.0 times the final wire diameter. By performing intermediate heat treatment, it is possible to reduce the processing distortion of the Al phase and promote recrystallization, and by adjusting the Al phase primarily, it becomes easier to adjust the shape ratio (c / d) of the Al phase in the subsequent final heat treatment. For example, if the intermediate heat treatment temperature is increased, the crystal grains of the Al phase become granular, and the shape ratio (c / d) tends to increase.

[0084] It is effective to set the temperature range of the final heat treatment to 250°C or higher and lower than 350°C, and the time to 2 hours or higher and lower than 24 hours. The aforementioned processing strain in the wire caused by wire drawing is used as the driving force to promote the progress of recrystallization of the Al phase and adjust the shape or crystal orientation of the crystal grains. For example, if the final heat treatment is performed at a low temperature for a long time, the crystal grains of the Al phase tend to become granular and the shape ratio (c / d) tends to increase.

[0085] As mentioned above, the above is an example of the manufacture of Al bonding wire, which is a wire material, as a representative example of Al connecting material. The same procedure can be basically used to manufacture Al bonding ribbon, which is a strip material. The temperature and time of the heat treatment can be approximately the same as those described above. In addition, when manufacturing Al bonding ribbon by rolling processing, the reduction rate of the die can be replaced with the reduction rate to adjust it.

[0086] [Semiconductor Devices] A semiconductor device can be manufactured by connecting electrodes on a semiconductor chip to external electrodes on a lead frame or substrate using the Al connecting material of the present invention. As mentioned above, wedge bonding is used for both the first bonding with the electrodes on the semiconductor chip and the second bonding with the electrodes on the lead frame or substrate.

[0087] In one embodiment, the semiconductor device of the present invention includes a circuit board, a semiconductor chip, and an Al connecting material for electrically connecting the circuit board and the semiconductor chip, and is characterized in that the Al connecting material is the Al connecting material of the present invention.

[0088] In the semiconductor device of the present invention, the circuit board and the semiconductor chip are not particularly limited, and a known circuit board and a semiconductor chip that can be used to configure a semiconductor device may be used. Alternatively, a lead frame may be used instead of the circuit board. For example, the semiconductor device may be configured to include a lead frame and a semiconductor chip mounted on the lead frame, as in the semiconductor device described in JP 2020-150116 A.

[0089] Examples of the semiconductor device include various semiconductor devices used in electrical products (e.g., computers, mobile phones, digital cameras, televisions, air conditioners, solar power generation systems, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.), and among these, power semiconductor devices are preferred. EXAMPLES

[0090] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the examples shown below.

[0091] (sample) The method of preparing the samples will be described. The raw material Al had a purity of 4N (99.99% by mass or more), with the remainder consisting of inevitable impurities. The alloying elements Si, the first element group (Sr, Na, Ca, B), and the second element group (Fe, Mg, P, Ti) had a purity of 99.99% by mass or more, with the remainder consisting of inevitable impurities. The Al alloy used for the Al connecting material was produced by loading the Al raw material and the raw material of the alloying elements into an alumina crucible and melting them using a high-frequency heating furnace. The atmosphere in the furnace during melting was an Ar atmosphere, and the maximum temperature of the molten metal during melting was 800 to 1050°C. The cooling method after melting was air cooling in the air or water cooling in water.

[0092] A cylindrical ingot with a diameter of 6 mm was obtained by melting, and the ingot was subjected to solution treatment and homogenization treatment, followed by wire drawing using a die and intermediate heat treatment to produce an Al connection material (Al bonding wire) with a diameter of 300 μm. The temperature range of the solution treatment was 400°C or higher and lower than 550°C, and the time was 1 hour or higher and lower than 6 hours. After the solution treatment, a homogenization treatment was performed continuously during cooling. The temperature range of the homogenization treatment was 250°C or higher and lower than 350°C, and the time was 2 hours or higher and lower than 6 hours. The cooling method after the homogenization treatment was air cooling in the atmosphere.

[0093] A commercially available lubricant was used during the wire drawing process, and the wire area reduction rate per die during the wire drawing process was set to 12.5% ​​or more and less than 18.0%. The temperature range of the final heat treatment was set to 250°C or more and less than 350°C, and the final heat treatment time was set to 2 hours or more and less than 24 hours.

[0094] In some examples, the wire feed speed in the wire drawing process 1 was 10 m / min or more and less than 25 m / min, and the wire feed speed in the wire drawing process 2 was 30 m / min or more and less than 50 m / min. In some examples, the temperature range of the intermediate heat treatment was 300°C or more and less than 450°C, and the time period was 30 minutes or more and less than 3 hours. The intermediate heat treatment was performed once, with a wire diameter 2.5 to 4.0 times the final wire diameter.

[0095] (Method of measuring element content) The concentration of elements contained in the Al connecting material was measured using an ICP-OES ("PS3520UVDDII" manufactured by Hitachi High-Tech Science Corporation) or an ICP-MS ("Agilent 7700x ICP-MS" manufactured by Agilent Technologies, Inc.) as an analytical device.

[0096] The specific electrical resistance of the Al connecting material was measured by a DC four-terminal measurement method. In detail, a resistance meter, DM7275 manufactured by Hioki E.E. Corporation, was used to measure the electrical resistance of the sample at room temperature with a sample length of 200 mm and a measurement current range of 0.02 to 0.1 mA. The measurements were performed five times, and the electrical resistance value R of each sample was calculated as the arithmetic average. If the electrical resistance value is R, the length of the sample is L, and the cross-sectional area of ​​the sample is S, the specific electrical resistance value M was calculated as R × (S / L).

[0097] (Method for measuring the orientation ratio of the crystal orientations of the Al phase and the Si phase) The L-section (cross section in the central axis direction including the central axis) of the Al connecting material was used as the inspection surface, and the crystal orientation of the Al phase and the Si phase was measured. In the present invention, the central axis of the Al connecting material and the cross section in the central axis direction including the central axis (L-section) are as shown in FIG. 1. FIG. 1 shows a case where the Al connecting material is an Al bonding wire having a circular cross-sectional shape, but when the Al connecting material is an Al bonding ribbon having a rectangular or approximately rectangular cross-sectional shape with a width W and a thickness T, the central axis refers to the axis passing through the center of the width W and the center of the thickness T, and the L-section refers to a cross section in the central axis direction including the central axis and in the direction of the thickness T. When processing the cross section to expose the L-section of the Al connecting material, it may deviate from the central axis of the Al connecting material. In this case, if the length in the direction perpendicular to the central axis of the L-section is 90% or more of the wire diameter of the Al connecting material (thickness T in the case of a ribbon), it can be considered as a cross section including the central axis.

[0098] In addition, FE-SEM (SU-70 manufactured by Hitachi High-Technologies Corporation) was used for the measurement, and either or both of OIM Data Collection and OIM Anaysis (both manufactured by TSL Solutions Corporation) were used for the analysis software. Three measurement areas were randomly selected at intervals of 50 cm or more in the direction of the central axis of the Al connecting material, and measurements were performed on the three areas. The measurement area was determined so that the measurement area was 300 μm or more and less than 800 μm in the direction of the central axis of the Al connecting material, and the entire Al connecting material was included in the direction perpendicular to the central axis. In addition, the main conditions of the EDS and EBSD measurements were set to an acceleration voltage of 15 kV, a scan speed of 30 to 120 points / sec, a measurement magnification of 350 times, and a measurement interval of 0.1 to 0.3 μm. Here, if the scan speed is fast, the measurement time can be shortened, but there is a concern that the measurement accuracy of EDS will decrease. It is desirable to select an appropriate scan speed within the above range.

[0099] -Crystal orientation of Al phase- The orientation ratio of the Al phase crystal orientation in the L cross section of the Al joint material was measured by combining the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by EBSD. In detail, the measurement was carried out according to the following steps (1) to (3). (1) In the measurement area where the L-section of the Al joint was used as the inspection surface, the Al and Si concentrations were measured using EDS and the crystal orientation was measured using EBSD simultaneously. (2) The Chi Scan function of the EBSD analysis software was used to separate and extract Al and Si. Specifically, Al and Si were separated and identified by setting a tolerance equivalent to the Si threshold from the Si EDS measurement results. The crystal orientation was analyzed using the crystal information of Al and Si from the material file. Here, the tolerance condition was mainly set to 30%, and was adjusted as necessary. (3) The crystal orientation of the region identified as the Al phase was analyzed, and the Al phase <110> The orientation ratio of the crystal orientation and <111> The orientation ratio of the crystal orientation was calculated. The crystal orientation to be investigated is the typical crystal orientation of Al metal. <111> , <110> , <100> At least three of the above were selected, and the crystal orientation with the highest ratio was selected as necessary. Here, the partial ratio was used for the orientation ratio of the crystal orientations.

[0100] Al phase <110> The orientation ratio of the crystal orientation and <111> The orientation ratio of the crystal orientation was determined as the average value of the values ​​obtained for the three measurement regions by the above steps (1) to (3).

[0101] -Crystal orientation of the Si phase- The orientation ratio of the crystal orientation of the Si phase in the L cross section of the Al joint material was measured using a method that combines the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by EBSD, in the same way as in the measurement of the orientation ratio of the crystal orientation of the Al phase. In detail, after carrying out the above steps (1) and (2), the measurement was carried out according to the following step (3). (3) The crystal orientation of the region identified as the Si phase was analyzed, and the Si phase <111> The orientation ratio of the crystal orientation and <110> The orientation ratio of the crystal orientation was calculated. The partial ratio was used for the orientation ratio of the crystal orientation.

[0102] The values ​​obtained by the above steps (1) to (3) for the three measurement areas were arithmetically averaged to obtain the Si phase. <111> The orientation ratio of the crystal orientation and <110> The orientation ratio of the crystal orientation was calculated.

[0103] (Method for measuring the shape of the Al phase) The shape (shape ratio (c / d)) of the Al phase in the L cross section of the Al connector was measured using a method that combined the information on the Al concentration and Si concentration obtained by SEM-EDS with the information on the crystal orientation obtained by EBSD, in the same way as in the measurement of the orientation ratio of the crystal orientation of the Al phase. In detail, after carrying out the above steps (1) and (2), the measurement was carried out according to the following step (3). (3) The crystal orientation of the region identified as Al phase was analyzed, and if the orientation difference between the measurement points was 15° or more, it was determined to be a grain boundary, and the shape ratio (c / d) of each grain was calculated. The shape ratio (c / d) of each grain was then averaged to calculate the average value of the shape ratio (c / d) of the Al phase. Here, the average value of the shape ratio (c / d) of the Al phase was calculated using the value of the Grain Shape Aspect Ratio ("Grain Shape Aspect Ratio") of the analysis software. Here, the software automatically calculates the ratio (c / d) of the short side length (c) (Grain Shape Minor Axis) and the long side length (d) (Grain Shape Major Axis) of one crystal grain. Here, the average value calculated by the area average was used for the average calculation.

[0104] (Evaluation method for Al connecting materials) The evaluation method of the Al connecting material will be explained. The wire diameter of the Al connecting material (Al bonding wire) used for the evaluation was Φ300μm. The semiconductor chip used was made of Si, and the electrodes on the semiconductor chip were made of an alloy with a composition of Al-0.5%Cu, which was deposited to a thickness of 4μm. The substrate used was an Al alloy with a Ni film deposited to a thickness of 5μm. A commercially available wire bonder (manufactured by Ultrasonic Industries Co., Ltd.) was used to bond the Al connecting material, and both the 1st and 2nd bondings were wedge bonded.

[0105] (Method of evaluating reliability of high-speed temperature cycles) A commercially available high-speed thermal shock tester was used to evaluate the high-speed temperature cycle test (high-speed TCT). In the high-speed TCT, hot air is blown onto the sample to rapidly heat it up. The sample to be subjected to the high-speed TCT has a structure in which a semiconductor chip is mounted on a substrate, and the electrodes on the semiconductor chip and the electrodes on the substrate are connected with an Al connecting material. The sample placed in the sample chamber of the high-speed thermal shock tester was repeatedly subjected to thermal loads, with heating and cooling being one cycle. The minimum temperature during cooling was -50°C, and the maximum temperature during heating was 175°C. The heating time, including the heating time, was 20 seconds, and the cooling time, including the cooling time, was 40 seconds. After the start of the test, the sample was taken out after 10,000 cycles, and a shear strength test of the 1st joint was performed. The shear strength value of the 1st joint used to evaluate the high-speed temperature cycle reliability was the average value of the shear strength of 10 randomly selected 1st joints. The ratio (percentage) of the average shear strength after the high-speed TCT to the average shear strength before the test was taken as the strength retention rate. The higher the strength retention rate, the better the reliability of the joint. If the strength retention rate is 85% or more, it is judged to be particularly excellent and given a rating of "4", if it is between 80% and 85%, it is judged to be good and given a rating of "3", if it is between 75% and 80%, it is judged to be good and given a rating of "2", if it is between 70% and 75%, it is judged to need improvement and given a rating of "1", and if it is less than 70%, it is judged to have practical problems and given a rating of "0". "4", "3", and "2" are pass marks, while "1" and "0" are fail marks. The evaluation results are shown in the "High-speed temperature cycle reliability (10,000 times)" column in the table. The temperature cycle reliability requirement for next-generation power semiconductor devices corresponds to 10,000 cycles.

[0106] (1st bonding strength evaluation method) The evaluation method of the 1st joint strength is explained below. The 1st joint strength was evaluated by a shear strength test. The 1st joint was performed at 10 places under general joining conditions, and the shear strength of the 1st joint was measured. A commercially available micro shear strength tester (Nordson 4000-PLUS) was used to measure the shear strength. The shear speed was 200 μm / sec, and the height of the shear tool was 10 μm from the electrode surface. The shear strength was measured by fixing the substrate to which the Al connection material was joined with a jig. If the average value of the shear strength of the 10 1st joints was 1600 gf or more, it was judged to be excellent and rated as "3", if it was 1400 gf or more but less than 1600 gf, it was judged to be practically acceptable and rated as "2", if it was 1000 gf or more but less than 1400 gf, it was judged to need improvement and rated as "1", and if it was less than 1000 gf, it was judged to be practically problematic and rated as "0". The evaluation results are shown in the "1st bonding strength" column in the table.

[0107] (Method of evaluating damage to semiconductor chips) Damage to the semiconductor chip was evaluated by dissolving the metal on the pad surface with acid and observing under the pad with a microscope (number of evaluations N = 50). A good case with no visible cracks or bonding traces was given a grade of "3," a case with no cracks but some visible bonding traces (3 or less out of 50 evaluations) was given a grade of "2," and all other cases were given a grade of "1," and these were recorded in the "Chip Damage" column in the table.

[0108] (Evaluation method for 1st joint hollow) The method for evaluating the hollow defect of the 1st joint is explained below. After the shear strength test of the 1st joint described above, the indentation on the fracture surface on the electrode side was observed with an optical microscope or SEM, and the area where no metal bonding was obtained in the fractured area was judged to be hollow. The area where hollow occurred is an area where the electrode is not bonded even if it is deformed, and can be distinguished from the area where the joint is metallically bonded. The shear strength test was performed under the above conditions, and the fracture surface of 10 1st joints was observed. Then, the ratio of the total length of the hollow area in the joint width direction (K) to the joint length (J) in the direction perpendicular to the central axis of the Al connecting material (joint width direction) was calculated as the hollow ratio (K / J) (Fig. 3). The hollow ratio was confirmed on the fracture surfaces of 10 places, and the maximum value was defined as the "hollow defect rate." If the defect rate of hollow parts was less than 5%, it was judged to be good and rated as "3", if it was between 5% and 15%, it was judged to be no problem for practical use and rated as "2", if it was between 15% and 25%, it was judged to require improvement and rated as "1", and if it was over 25%, it was judged to be an obstacle to mass production and rated as "0". The evaluation results are shown in the "Hollow parts of 1st joint" column in the table.

[0109] (Method of evaluating stability of bonding width) The evaluation method of the joint width stability will be explained. After the above-mentioned shear strength test of the 1st joint, the indentation width (joint width) of the indentation on the fracture surface on the electrode side was evaluated. In detail, for the indentation on the fracture surface, the joint length (J) in the direction perpendicular to the central axis of the Al connecting material was measured at the center position of the joint length in the central axis direction of the Al connecting material, and the population standard deviation (σ) was calculated. When σ was 15 μm or more, it was judged to be problematic in practical use and rated as "1", when σ was 5 μm or more and less than 15 μm, it was judged to be good and rated as "2", and when σ was less than 5 μm, it was judged to be excellent and rated as "3". "1" is a failure, and "2" and "3" are passes. The evaluation results are shown in the "Stability of joint width" column in the table.

[0110] (Method of evaluating internal cracks) The method of evaluating the internal cracks of the Al connecting material will be described. The manufactured Al connecting material was evaluated by observation (hereinafter referred to as X-ray observation) using a soft X-ray projection inspection device (Matsusada Precision, μB2600). The measurement conditions of the X-ray observation can be appropriately determined according to the wire diameter of the Al connecting material, but in the case of the Al connecting material with a wire diameter of 300 μm manufactured in this embodiment, the voltage was adjusted to 50 to 80 kV and the current to 60 to 90 μA. Three points were randomly selected at intervals of 1 m or more in the central axis direction of the Al connecting material, and three samples with a length of about 8 cm were selected at each of the three points, resulting in a total of nine measurement samples. FIG. 4 shows an example of X-ray observation of an Al connecting material with a wire diameter of 300 μm, in which internal cracks are observed. If the length of the internal crack is 0.3 mm or more, it is judged to be a problematic defect and scored as "2", and if it is 0.1 mm or more but less than 0.3 mm, it is judged to require attention and scored as "0.5". The sum of the scores for the measurement points was set as the "crack index." For the crack index of the entire measured sample, zero was judged to be good and rated "3," while a value between 0.1 and 2.0 was judged to be acceptable for practical use and rated "2," a value between 2.0 and 5.0 was judged to require improvement and rated "1," and a value over 6.0 was judged to be difficult to use and rated "0." The evaluation results are shown in the "internal crack" column in the table.

[0111] (Evaluation method for surface scratches and scrapes) The surface quality of the Al connector was evaluated with a focus on scratches and chipping. Three measurement areas were randomly selected at intervals of 1 m or more along the central axis of the Al connector, and three samples of approximately 2 cm in length were taken from each of the three areas, for a total of nine samples. The surface was observed at magnifications ranging from 50 to 500 times with an SEM. Scratches longer than 50 μm and chipping longer than 30 μm were judged to be defective. The number of scratches and chips was counted, and if there were zero, it was judged to be good and passed, giving a rating of "3," if there were two or less, it was judged to be acceptable for practical use, giving a rating of "2," if there were three to seven, it was judged to have poor surface quality, giving a rating of "1," and if there were eight or more, it was judged to be difficult to use, giving a rating of "0." The evaluation results are shown in the "Surface Quality" column in the table.

[0112] The evaluation results of the examples and comparative examples are shown in Tables 1 to 3.

[0113] [Table 1]

[0114] [Table 2]

[0115] [Table 3]

[0116] All of the Al connecting materials of Examples 1 to 58 contained 4.0 mass% or more and 12.0 mass% or less of Si, and had a specific electrical resistivity Ra of 2.6 × 10 -8 Ωm or more 3.6×10 -8 Ωm or less, and the Al phase in the L section <110> + <111> The total ratio is 20% or more and 70% or less (however, when the total of the orientation ratios is 25% or less, the angle difference with respect to the central axis direction is 15° or less. <110> It was confirmed that the crystal orientation ratio was 5% or more, and that the material exhibited good temperature cycle reliability even in high-speed TCT, as well as good 1st bond strength. In addition, the Al phase in the L section <110> It was confirmed that the Al connecting materials of Examples 1 to 13, 15 to 30, 32 to 50, 52, 53, and 55 to 58, which have a ratio of 5% or more and 50% or less, exhibited better results in the first joint strength and were easier to prevent hollowing out of the first joint. Si phase in L cross section <111> + <110> It was confirmed that the Al connecting materials of Examples 1 to 37 and 40 to 58, in which the total ratio was 20% or more and 70% or less, tended to have better temperature cycle reliability in high-speed TCT. It was confirmed that the Al connecting materials of Examples 1 to 6, 8 to 23, and 25 to 58, in which the average shape ratio (c / d) of the Al phase in the L cross section is 0.2 or more and 0.7 or less, tend to reduce the variation in the joint width during joining and stabilize the joint width. Furthermore, it was confirmed that the Al connecting materials of Examples 27 to 33, 35 to 37, 48 to 51, and 55 to 58, which contain at least one element from the first element group (Sr, Na, Ca, B) in a total amount of 5 ppm by mass or more and 800 ppm by mass or less, can reduce internal cracks during processing. It was confirmed that the Al connecting materials of Examples 39 to 51 and 53 to 58, which contain a total of 5 mass ppm or more and 500 mass ppm or less of one or more of the second element group (Fe, Mg, P, Ti), have a smooth surface with reduced surface scratches and chipping. On the other hand, the Al connectors of Comparative Examples Nos. 1 to 10 have Si concentration, specific electrical resistance, and Al phase in the L cross section. <110> + <111> Total ratio (if the total ratio is 25% or less, the Al phase <110> It was confirmed that either the above-mentioned properties (including the ratio) was outside the range of the present invention, and that either the high-speed temperature cycle reliability or the first bonding strength was not sufficiently obtained.

Claims

1. An Al connecting material containing 4.0 mass% or more and 12.0 mass% or less of Si, Specific electrical resistance Ra is 2.6 x 10 －８ Ωm or more 3.6 x 10 －８ Ωm or less, When the crystal orientation of the Al phase in the L-section (a cross section in the central axis direction including the central axis) of the Al connecting material is measured, the total orientation ratio of the <110> crystal orientation and the <111> crystal orientation, which have an angular difference of 15° or less with respect to the central axis, is 20% or more and 70% or less, and when the total orientation ratio is 25% or less, the orientation ratio of the <110> crystal orientation, which has an angular difference of 15° or less with respect to the central axis, is 5% or more.

2. 2. The Al connecting material according to claim 1, wherein the ratio of the <110> crystal orientation, which has an angle difference of 15° or less with respect to the central axis direction, in the crystal orientation of the Al phase in the L cross section is 5% or more and 50% or less.

3. 2. The Al connecting material according to claim 1, wherein, when the crystal orientation of the Si phase in the L cross section is measured, the total orientation ratio of the <111> crystal orientation and the <110> crystal orientation, which have an angular difference of 15° or less with respect to the central axis direction, is 20% or more and 70% or less.

4. 2. The Al connecting material according to claim 1, wherein the average ratio (c / d) of the short side length c to the long side length d of the Al phase in the L cross section is 0.2 or more and 0.7 or less.

5. The Al connecting material according to claim 1, further containing at least one of Sr, Na, Ca, and B in a total amount of 5 ppm by mass to 800 ppm by mass.

6. The Al connecting material according to claim 1, further containing at least one of Fe, Mg, P, and Ti in a total amount of 5 ppm by mass to 500 ppm by mass.

7. The Al connecting material according to claim 5, further containing at least one of Fe, Mg, P, and Ti in a total amount of 5 ppm by mass to 500 ppm by mass.

8. The Al connecting material according to any one of claims 1 to 7, wherein the total concentration of other elements in the Al connecting material is 0.5 mass% or less.

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