JP2005268771A - Gold bonding wire for semiconductor device and connection method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding wire for a semiconductor element capable of improving a good roundness at a ball bonded portion or increasing a bonding strength in order to realize high-density mounting, low-temperature connection, and the like.
A gold bonding wire in which a ball portion formed at an end portion is bonded to a substrate electrode portion, and a crystal grain structure of a cross section of the ball portion perpendicular to the longitudinal direction of the wire, or a ball in a direction horizontal to the substrate surface. A gold bonding wire for a semiconductor device in which crystal orientations such as a [111] orientation and a [100] orientation are controlled in a crystal grain structure of a junction cross section.
[Selection] Figure 1

Description

  The present invention relates to a gold bonding wire for a semiconductor device used for connecting an electrode on a semiconductor element and an external lead, and a method for connecting the gold bonding wire.

  Currently, gold bonding wires for connecting between electrodes on semiconductor elements and external terminals are gold bonding having a wire diameter of about 20 to 50 μm and a high purity 4N-based (purity> 99.99 mass%) gold. Wire is mainly used. The bonding technique for gold bonding wires is generally an ultrasonic thermocompression bonding method, and requires a general-purpose bonding apparatus, a capillary jig for connecting wires through the inside thereof, and the like. After the wire tip is heated and melted by arc heat input and a ball is formed by surface tension, the ball part is crimped and bonded onto the electrode of the semiconductor element heated within the range of 150 to 300 ° C., and then the wire is directly connected. The wedge is joined to the external lead side by ultrasonic pressure bonding. For use as a semiconductor device such as a transistor or an IC, an epoxy is used for the purpose of protecting the Si chip, the gold bonding wire, and the lead frame where the Si chip is attached after bonding with the gold bonding wire. Seal with resin. Although it is necessary to improve the individual characteristics of these members, it is increasingly important to improve the overall performance and reliability, such as the relationship with the surrounding members and usage.

  Due to the trend toward high integration and thinning of semiconductor elements, the characteristics that gold bonding wires must satisfy are diversified. For example, the gold bonding wires can be made longer, thinner or thinner to accommodate high-density wiring and narrow pitch. There is a demand for lower loops and the like to enable higher loops and thinner semiconductor elements.

  For example, in a resin sealing process in which high-viscosity thermosetting epoxy resin is injected at a high speed, there is a problem that the wire is deformed and comes into contact with an adjacent wire, and further, narrow pitch, long wire, and thinning are progressing. Therefore, it is required to suppress even a little wire deformation (hereinafter referred to as wire flow) during resin sealing. Above all, the need for narrow pitch is accelerating, and the current mass production level is 60 μm pitch, but the development of 50 μm pitch is also progressing, and furthermore, the pole that was considered the limit of ball bonding until several years ago Practical application after 2 to 3 years is expected up to a narrow pitch of 45 μm. Furthermore, in the roadmap regarding the mounting technology, a technology for realizing an extremely narrow pitch of 20 μm is beginning to be expected in the future.

  The basic characteristics of a wire that satisfies these requirements are that the loop shape in the bonding process can be controlled with high precision, and that the bondability to the electrode and lead parts has been improved, as well as wire deformation in the mounting process after bonding. It is desirable to satisfy comprehensive characteristics such as being able to be suppressed.

  Until now, the addition of a plurality of alloy elements has been the mainstream as means for increasing the strength of gold bonding wires. In current high-purity gold bonding wires, the addition of alloying elements is limited to several ppm to several tens of ppm in order to prevent oxidation of the ball part and increase in electrical resistance. Although excellent, suppression of wire deformation and the strength of the heat-affected zone (neck portion) during ball formation were not sufficient. Recently, high-concentration alloy wires that have been added up to a total of about 1% have begun to be used in some ICs, but the effect of improving wire deformation at the time of resin sealing is not sufficient. There are concerns about problems such as a decrease in bondability.

  As one method for achieving high strength, a multi-layer wire made of a metal having a different core part and outer peripheral part has been proposed. For example, in Patent Document 1, a wire in which an Ag core is covered with Au is disclosed in Patent Document 2. A wire or the like whose core is a conductive metal and whose surface is Au-plated is disclosed. By combining different metals in the core and outer periphery, these are expected to satisfy higher strength and higher bondability than wires made up of a single member in which all general-purpose products fall into the category. Has been. However, in actual semiconductors, there are almost no reports of examples using multilayer wires.

  Therefore, in order to adapt to future needs for high-density mounting, the wire does not satisfy only the individual required characteristics, but development of a material that comprehensively improves the characteristics is required.

JP-A-56-21254 JP 59-155161 A

  Due to demands such as the chip size of the semiconductor element and downsizing of the pad opening, it is required to satisfy strict requirements for ensuring the bonding strength even if the bonding area is reduced. For example, in a narrow pitch connection of 40 μm or less, the junction area may be reduced to ½ or less than the conventional 70 μm pitch, which is one of the causes of connection-related defects.

  The materials used for bonding gold bonding wires are also diversified. For wiring and electrode materials on silicon substrates, the conventional Al-Si alloy is changed to an Al-Si-Cu alloy, and then further transferred to an Al-Cu alloy. ing. In addition to Al alloys, Cu and Cu alloys suitable for higher integration have begun to be used. In such electrode members such as Al alloy, Cu, and Cu alloy, small ball bonding corresponding to narrow pitch is required, and it is more important to ensure bonding strength, ball deformation, high temperature bonding reliability, and the like. . In addition, narrow pitch connection has been put to practical use in semiconductor devices using resin substrates such as BGA and tape substrates, and these resins and tapes are inferior in heat resistance compared to conventional metal lead frames. Must be performed at low temperatures. Due to the low-temperature bonding, there is a problem that the bonding strength is reduced and the mass productivity at the time of continuous bonding is reduced.

  Conventionally, in the process of connecting the ball portion to the electrode portion of the semiconductor element, it is relatively easy to ensure the bonding strength and the like, and there are few problems in mass production. Therefore, among the required characteristics of gold bonding wires, the core design is to deal with high-strength thinning, control of loop shape, etc., and component design utilizing solid solution hardening in the wire, precipitation hardening, hardening of compound formation, etc. I have been. However, the conventional method of selecting the type and concentration of the additive element that relies on the use of solid solution, precipitation, compound formation, etc. of the alloying element with the aim of increasing the strength of the wire improves the bondability. It is difficult. The addition of ingredients is also expected to improve joint strength, but it is difficult to reduce deformation and variation in joint strength during mass production, and the reproducibility is not sufficient. The specific method was not revealed.

  Since ball deformation often depends on the performance of the bonding equipment, it is also helpful to increase the load, ultrasonic vibration, etc. in ball bonding, but the ball joint is excessively increased only by increasing the load, ultrasonic vibration. Another problem arises that it becomes larger and makes it difficult to make a narrow pitch connection or damages such as cracks directly under the electrode.

  Furthermore, the shape of the ball joint has not conventionally been required to be controlled very strictly, but with a narrow pitch connection, the ball joint tends to deviate from a perfect circle, resulting in ball joining from the electrode opening. There arises a problem that a part of the portion protrudes, and it becomes difficult to suppress defects by the size management of only the average value of the conventional ball joint portion.

  Therefore, it is important to reduce the anisotropy of the ball joint portion and improve the roundness on average. Even if the average value of the ball joint size can be managed, if the anisotropy rate and size variation cannot be reduced, it can be applied to semiconductor mass production processes that require a severe reduction in the defect rate. Is not enough. For example, multi-pin ICs in which the number of terminals of a semiconductor element exceeds 500 pins are increasing, and even if an abnormality occurs in ball bonding with only one pin, an expensive semiconductor element becomes a defective product. Regarding the shape and size of the joint, it is more important to stabilize the shape and size in the mass production process than to simply improve the average.

  The requirements for ball joints include not only the bonding performance of the mounting process that affects productivity, but also the long-term reliability of the joint even when wire-connected semiconductor devices are exposed to high-temperature environments or generate heat during operation. It is required to secure. It has been reported that the cause of a defect in the bonding portion of the gold bonding wire is the generation of Kirkendall void or the corrosion of the intermetallic compound formed in the bonding portion. In order to improve the long-term reliability of the joint, materials such as wires and sealing resins, connection methods, and the like have been studied. However, under severe bonding conditions such as a narrow pitch, the actual situation is that sufficient bonding reliability is not always ensured as compared with a normal relatively wide pitch connection. In order to improve such bonding reliability, it is not sufficient to adjust the wire components, and it is necessary to stabilize the shape, size, and the like of the above-described ball bonding portion.

  The present invention provides a narrow pitch, improves the shape of the ball joint in low-temperature joining, joining strength, etc., improves the high-temperature reliability of the joining part, and also provides mechanical properties such as strength, loop controllability, etc. An object of the present invention is to provide a gold bonding wire for a semiconductor element and a connection method thereof, which are industrially excellent in mass productivity.

  From the above-mentioned viewpoint, the present inventors improve the shape and size of the ball joint for realizing narrow pitch connection, improve the long-term reliability, etc., and further improve the wire flow suppression and the like comprehensively. As a result of research and development for this purpose, it is important and effective to control the structure of the ball and ball joint formed at the end, and the texture of the wire to promote the formation of the ball. I found it for the first time.

That is, the gist of the present invention for achieving the above-described object is as follows.
(1) A gold bonding wire in which a ball part formed at an end part is joined to a substrate electrode part, and the [100] orientation is selected from crystal orientations in the direction perpendicular to the cross section of the ball joint part in the horizontal direction with respect to the substrate surface. The ratio of the area of the crystal grain which has a [111] direction with respect to the area of the crystal grain which it has is 1.1 or more, The gold bonding wire for semiconductor devices characterized by the above-mentioned.
(2) A gold bonding wire in which a ball portion formed at an end portion is bonded to a substrate electrode portion, and a crystal orientation in a direction perpendicular to the cross section in the cross section of the ball bonding portion in the horizontal direction with respect to the substrate surface is [ A gold bonding wire for a semiconductor device, wherein the area ratio of crystal grains having a [111] orientation and a [100] orientation is in the range of 30 to 95%.
(3) A gold bonding wire in which a ball part formed at an end part is joined to a substrate electrode part, and the substrate surface and the horizontal direction in the crystal orientation in the vertical direction of the cross section of the ball joint part in the horizontal direction of the substrate surface. The area of the crystal grain having the [111] orientation relative to the area of the crystal grain having the [100] orientation in the core when the portion from the center of the cross section of the ball joint to the half of the joint ball radius D is used as the core The gold bonding wire for a semiconductor device, wherein the ratio is 3 or less.
(4) A gold bonding wire in which a ball part formed at an end part is joined to a substrate electrode part, and the substrate surface and a horizontal direction in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint part in the horizontal direction. Crystal grains having a [111] orientation relative to the area of the crystal grains having a [100] orientation in the outer peripheral portion when a portion outside 2/3 of the joint ball radius D from the center of the cross section of the ball connecting portion is taken as the outer peripheral portion. A gold bonding wire for a semiconductor device, wherein the area ratio is 0.9 or more.
(5) A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and of the crystal orientation in the vertical direction of the cross section in the cross section of the ball bonding portion in the horizontal direction with respect to the substrate surface. A crystal having a [111] orientation in at least one of the outermost peripheral region which is a portion outside 4/5 of the ball radius D from the center of the cross section of the ball joint portion and the outermost crystal grain included in the outermost peripheral region A gold bonding wire for a semiconductor device, wherein the total area ratio of grains is 50% or more.
(6) A crystal having a [111] orientation in the body region, wherein a region that does not belong to either the outermost peripheral region or the outermost crystal grain included in the outermost peripheral region in the ball joint cross section The gold bonding wire for a semiconductor device according to (5), wherein the total area ratio of the grains is 40% or less.
(7) A gold bonding wire in which a ball portion formed at an end portion is bonded to a substrate electrode portion, and the crystal orientation in the vertical direction of the cross section in the cross section of the ball bonding portion in the horizontal direction with respect to the substrate surface is [ 112], [113], [114], a gold bonding wire for a semiconductor device, wherein the total area ratio of crystal grains having the [115] orientation is in the range of 3 to 40%.
(8) When the length of the line segment passing through the center of gravity of the cross section of the ball joint is d, the relationship between the average value M and the standard deviation SD when the length d is measured at any three or more locations of the cross section Is a gold bonding wire for a semiconductor device according to any one of the above (1) to (5), wherein SD / M ≦ 0.3 is satisfied.
(9) It consists of a main component of the bonding wire and a main component of the electrode part at the bonding interface between the ball part of the gold bonding wire and the substrate electrode part in which the ball part formed at the end is bonded to the substrate electrode part. The gold bonding wire for a semiconductor device according to any one of (1) to (6), wherein the formation ratio of the intermetallic compound is 65% or more of the entire bonding interface.
(10) A gold bonding wire that forms a ball portion at an end portion, and has a [100] orientation among crystal orientations in the wire longitudinal direction in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball portion A gold bonding wire for a semiconductor device, wherein the ratio of the area of crystal grains having [111] orientation to the area of crystal grains is 1.1 or more.
(11) A gold bonding wire for forming a ball part at an end, and in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball part, [111 A gold bonding wire for a semiconductor device, wherein the area ratio of crystal grains having an orientation is 35% or more.
(12) A gold bonding wire that forms a ball portion at an end, and a portion from the center of the ball portion to 1/2 of the ball radius R in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball portion Is the ratio Rd of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation out of the crystal orientation in the longitudinal direction of the wire in the central area, The ratio Ra of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation is | 1-Rd / Ra | ≦ 3. The gold bonding wire for semiconductor devices as described.
(13) In the crystal grain structure in the longitudinal cross section of the wire portion excluding the heat affected zone of the gold bonding wire, the crystal structure is divided into 3 for every 1/3 of the wire radius L from the center of the wire, and the center portion (c), inner layer Of the crystal orientations in the wire longitudinal direction in the part (g) and the outer layer part (s), the ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation is Lc, Lg, Ls, respectively. As described above, a gold bonding wire for a semiconductor device satisfying at least two of the relationships of Lc ≦ 3, Lg ≧ 0.8, and Ls ≧ 0.5.
(14) The above (1) to (5), (8), (9), wherein the [111] orientation and [100] orientation crystal grains have an inclination of 10 ° or less with respect to the longitudinal direction of the bonding wire. (11) A gold bonding wire for a semiconductor device according to any one of (11).
(15) In the crystal grains in the cross section, the ratio of the crystal grain boundaries in which the angle difference between the orientations of adjacent crystal grains is 30 ° or less occupies 50% or more of the grain boundaries of all crystal grains. (5), (8), (9), The gold bonding wire for semiconductor devices in any one of (11).
(16) The above (1) to (7), (10), (11), (11), wherein the number of crystal grains in the cross-sectional structure of the ball part or ball joint part is 0.005 to 0.1 / μm ^2. The gold bonding wire for semiconductor devices as described in 13).
(17) Any of (1) to (7), (10), (11), and (13) above, wherein the standard deviation of the crystal grain size in the cross-sectional structure of the ball portion or ball joint portion is 1.5 μm or less. Gold bonding wires for semiconductor devices as described in 1.
(18) Au as a main component and additive components: Be: 0.0001 to 0.0008 mass%, Ca: 0.001 to 0.005 mass%, Eu: 0.0005 to 0.004 mass%, Nd : 0.0005-0.004 mass%, Yb: 0.0005-0.005 mass%, Cu: 0.001-0.4 mass%, Pd: 0.001-0.6 mass%, Ag, Mn The gold bonding wire for a semiconductor device according to any one of claims 1 to 17, wherein 0.0005 to 0.2 mass of one or more of Pt is contained.
(19) Using the gold bonding wire for a semiconductor device according to any one of (1) to (18), ball bonding and wedge bonding are repeatedly performed on an electrode portion formed on a semiconductor chip and a substrate, A bonding method of a gold bonding wire for connecting a bonding portion and a bonding wire, wherein a ball portion is formed by arc discharge at an end portion of the bonding wire, and when the ball portion is bonded to an electrode portion on a semiconductor chip, When the wire diameter is 2L, the length of the deformed end whose wedge-bonded diameter is 10% or more thinner than the original diameter is 0.8L-4L. The gold bonder is characterized in that arc discharge is performed from the direction in which the angle of 0 to 45 ° is applied to form a ball portion having a radius of 1.2 L to 2.0 L, and then the ball bonding is performed. Connection method of Nguwaiya.
(20) A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and a [100] orientation is selected from crystal orientations in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with the substrate surface. A semiconductor device including a ball bonding portion in which a ratio of an area of a crystal grain having a [111] orientation to a crystal grain area is 1.1 or more.
(21) A semiconductor device in which an electrode part on a semiconductor substrate and an external terminal are connected by a bonding wire, and the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint in the horizontal direction with respect to the substrate surface is [ A semiconductor device comprising a ball bonding portion in which an area ratio of crystal grains having a [111] orientation and a [100] orientation is in a range of 30 to 95%.
(22) A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and the substrate surface and the horizontal direction in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction The area of the crystal grain having the [111] orientation relative to the area of the crystal grain having the [100] orientation in the core when the portion from the center of the cross section of the ball joint to the half of the joint ball radius D is used as the core A semiconductor device having a ball joint portion with a ratio of 3 or less.
(23) A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and the substrate surface and a horizontal direction in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction Crystal grains having a [111] orientation with respect to the area of the crystal grains having a [100] orientation in the outer peripheral portion when a portion outside 2/3 of the bonding ball radius D from the center of the cross section of the ball connecting portion is taken as the outer peripheral portion. A semiconductor device comprising a ball bonding portion having an area ratio of 0.9 or more.
(24) A semiconductor device in which an electrode part on a semiconductor substrate and an external terminal are connected by a bonding wire, and a crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with respect to the substrate surface is [ 112], [113], [114], a semiconductor device characterized by having a ball bonding portion in which the total area ratio of crystal grains having the [115] orientation is in the range of 3 to 40%.

  When the bonding wire and the connection method of the present invention are used, a ball portion having a stable shape, dimensions, etc. is formed at the end of the wire, and when the ball portion is joined to the substrate electrode portion, a stable ball having good roundness A joint part can be obtained and joint strength can be raised. Therefore, by using the bonding wire of the present invention, it is possible to improve the high-temperature mounting and the low-temperature bonding property by narrowing the pitch, thereby improving the bonding property to the substrate, and further improving the high-temperature reliability of the ball bonding portion. Furthermore, mechanical properties such as strength, loop controllability, etc. can be improved.

  In the ball portion at the end of the gold bonding wire formed by melting by arc discharge, it is easily affected by heat conduction in the wire direction, and a solidified structure different from the wire structure is formed. As for the solidified structure of the ball part, the ball part was etched to make an appearance inspection or the structure inside the ball was polished, but the crystal orientation of the ball part was hardly clarified. . The relationship between the structure of the ball part and the ball joint part, ball deformation with a narrow pitch wire, joint strength, reliability, and the like are not known, and no effort has been made to control the crystal orientation.

  Pay attention to the relationship between the structure of the ball part and the ball joint part and these joining characteristics, and by controlling the crystal orientation of the ball part and the ball joint part, the shape, size management, joint strength, etc. of the ball joint part can be improved. Furthermore, it has been found for the first time that the structure control of gold bonding wires, bonding conditions, and the like are effective in improving the structure of these ball portions and ball bonding portions. Such control of the ball structure is a material design that differs greatly from conventional wire development that relies solely on modification by wire components. Controlling the texture of the wire, the solidified structure of the ball and the deformed structure of the ball joint includes, in addition to improved bondability and joint reliability, higher strength, loop controllability, wire flow suppression, etc. It is also effective in improving overall usage performance.

  Hereinafter, a gold bonding wire for a semiconductor device according to the present invention, a ball bonding portion using the wire, a connection method, and the like will be described.

  When the structure of the ball portion was examined using a general-purpose gold wire, it was a solidified structure in which crystal grains grew greatly. When the crystal orientation in the longitudinal direction of the wire was measured, it is generally observed in fcc metals such as Au [111] , [100], [110] orientations, and higher crystal orientations are observed, the distribution of these crystal orientations is not fixed, and solidification observed in many ball parts and ball joints When the structures were compared, it was confirmed that the crystal orientation ratio was not constant and often fluctuated greatly. When the ball part is connected to the electrode part, the ball part undergoes considerable plastic deformation due to the application of load, ultrasonic vibration, etc., so the deformed processed structure of the ball joint part has a different aspect from the solidified structure of the ball part. It was confirmed to be present. For example, in a deformed structure of a ball joint portion in which a ball portion formed under conventional conditions is joined to the tip of a general-purpose gold wire, there are relatively few orientations such as [111] and [100] orientations, and there are various crystal orientations. It was confirmed that a lot of rotated intermediate orientations were observed, and that the ratio and distribution of crystal orientations had a large individual difference in the ball part.

  In the crystal orientation [hkl], even if the order of h, k, and l is different from the order of positive and negative, only the notation is different in the same direction, so the order of h, k, and l may differ from the order of h, k, and l. Including [hkl] is used as a representative example. For example, [111], [−111], [−1-11], [1-11], etc. are all represented by [111], and [100], [010], [00-1], etc. are all represented by [ 100] as a representative.

  When applied to the latest packaging technologies such as narrow pitch connection and low temperature connection using the conventional structure of the ball and ball joints, deformation anisotropy such as an elliptical shape occurs when the ball is deformed, and low pitch bonding at a narrow pitch. Occasionally, it caused many problems such as poor peeling at the bonding interface and large variations in bonding strength.

  On the other hand, it is a gold bonding wire in which the ball part formed at the end part is joined to the substrate electrode part, and the [100] orientation is selected from the crystal orientations in the vertical direction of the cross section in the cross section of the ball joint part in the horizontal direction with the substrate surface. The ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains (hereinafter abbreviated as [111] / [100] area ratio) is 1.1 or more, so that the ball portion It was found that a ball joint with good roundness can be obtained by suppressing the elliptical deformation of the ball joint connected on the electrode.

  The reason why the area ratio of [111] / [100] in the ball joint is set to 1.1 or more is that if it is less than 1.1, the frequency of occurrence of elliptical deformation increases. Preferably, the [111] / [100] area ratio is 1.3 or more. This is because if the area ratio is 1.3 or more, the effect of suppressing elliptical deformation is strong even if the output of the ultrasonic vibration is increased, and the roundness of the ball joint can be increased. Even more preferably, by setting the area ratio of [111] / [100] to 1.7 or more, the effect of promoting the deformation of the ball can be further enhanced, and the ball portion before joining to the wire diameter L of the wire can be improved. It is possible to improve productivity in small ball joining in which the ratio D / L of the diameter D is about 1.3 to 1.8. Moreover, there is no restriction | limiting in particular about the upper limit of the area ratio of [111] / [100], but if it is less than 40, stable manufacture is comparatively easy.

  Of the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint in the horizontal direction with the substrate surface, the area ratio of crystal grains having [111] orientation and [100] orientation to all crystal grains is in the range of 30 to 95%. Roundness can be improved by using a ball joint. Especially, the effect which suppresses eccentricity by the center of a ball | bowl joint part having shifted | deviated from the center of the wire immediately above is high, roundness can be improved, and the positional accuracy of a ball | bowl joint part can be improved. As for the form of the ball joint portion, FIG. 1A shows an excellent case where the center of the ball joint portion and the center of the wire substantially coincide with each other, and FIG.

  If the sum of the area ratios of crystal grains having the [111] orientation and the [100] orientation in the ball joint is less than 30%, the effect of suppressing the eccentricity is not sufficient, and the joining device used for general purposes This is because it is difficult to stably achieve more than 95% in mass production in consideration of variations such as the bonding jig (capillary). Preferably, if the total area ratio of the [111] orientation and the [100] orientation is in the range of 40 to 80%, the size of the ball joint portion can be easily stabilized.

  In addition to the average orientation control in the ball joint, the crystal grain orientation distribution in the ball joint or the structure control in the local portion is effective for promoting the perfect circle deformation of the ball joint. A specific example will be described below.

  Of the crystal orientation in the direction perpendicular to the cross section in the cross section of the ball joint in the horizontal direction with the surface of the substrate, when the portion from the center of the cross section of the ball joint in the horizontal direction in the horizontal direction to the half of the ball radius D is used as the core Since the ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation in the core is 3 or less, the positional deviation of the joint can be reduced, and the narrow pitch connection Etc. are advantageous. If the area ratio of [111] / [100] in the core part is more than 3, when the ball part comes into contact with the electrode and causes initial deformation, the ball part is preferentially deformed. This is because the position shift of the ball joint occurs due to the progress. Preferably, by setting the area ratio of [111] / [100] in the core to be in the range of 0.05 to 2, the destruction of the oxide film is promoted near the center of the ball bonding interface or the growth of the compound is promoted. By doing so, the bonding strength can be further increased. Also, the area ratio of [111] / [100] in the core is 3 or less and the area ratio of [111] / [100] is 1.1 or more, or [111] orientation and [100 ] When the area ratio of crystal grains having an orientation is in the range of 30 to 95%, the effect of increasing the bonding strength can be enhanced, which is advantageous for low-temperature connection or the like.

  In addition, regarding the distribution of the structure, when the outer portion from the position of 2/3 of the bonding ball radius D from the center of the ball bonding portion is defined as the outer peripheral portion, the cross section in the direction perpendicular to the cross section of the ball bonding portion in the horizontal direction with respect to the substrate surface is used. By setting the area ratio of [111] / [100] at the outer peripheral portion in the crystal orientation to be 0.9 or more, a defect in which petal-like irregularities are formed outside the ball joint portion is suppressed, and a perfect circle The sex can be increased. A schematic diagram of the irregularities on the outside of the ball joint is shown in FIG.

  When the petal-like deformation of the ball joint becomes prominent, it becomes difficult to secure the joint strength, or the management of the average value of the ball joint size generally performed in the manufacturing process stabilizes the mass productivity. May be difficult. On the other hand, if the area ratio of [111] / [100] at the outer peripheral portion is set to 0.9 or more, the effect that the crystal grains of the outer peripheral portion deform almost uniformly can be enhanced. Preferably, the effect which suppresses a petal-like deformation can be heightened more by setting it as the range of 1.1-20.

  Of the crystal orientation in the direction perpendicular to the cross-section in the cross section of the ball joint in the horizontal direction with the substrate surface, the outermost peripheral region that is a portion outside the radius 4/5 from the center of the cross section of the ball joint in the horizontal direction with the substrate surface Alternatively, in at least one of the outermost crystal grains included in the outermost peripheral region, the total of the area ratio of the crystal grains having the [111] orientation is 50% or more, so that the pad electrode is relatively difficult to bond. Bondability at the part can be improved. It is effective to control the crystal orientation of the outermost crystal grains of the ball in order to promote microscopic deformation and destruction of the oxide film and the contamination layer on the electrode surface. Here, the orientation control of crystal grains on the ball surface is the most effective in the cross section of the ball joint, but this crystal grain is too large, or the orientation difference between adjacent crystal grains is small, making it difficult to determine the grain boundary. In some cases, it has been found that the same effect can be obtained even in the orientation of crystal grains in the outermost peripheral region, which is an outer portion from 4/5 of the ball radius D. Here, if the total area ratio of the grains having the [111] orientation is 50% or more, the effect of increasing the bonding strength is enhanced. Preferably, if it is 65% or more, the defect rate such as peeling is reduced. A high effect of reducing can be obtained. The surface structure of the pad electrode that is difficult to bond is when the aluminum oxide film is relatively thick or when there is a contaminated layer such as an organic film or a fluoride film. If it is preferably 65% or more, even in the case of a contaminated layer such as an organic film or a fluoride film, a high effect of reducing the non-sticking rate can be obtained. Further, if it is 65% or more, it is effective even when the material of the pad electrode is copper. In order to obtain a good metal bond by destroying the copper oxide film, the orientation control of crystal grains on the ball surface is possible. Is effective.

  Further, the crystal orientation in the outermost peripheral region or the outermost crystal grains included in the outermost peripheral region is within the above range, and the outermost crystal grains included in the outermost peripheral region, which are other regions. A region not included in either is defined as a body region, and the total area ratio of crystal grains having [111] orientation in the body region is 40% or less, thereby improving the number of times the capillary is used (life). A high effect of improving the property and suppressing damage to the chip under the electrode can be obtained. At the tip of the capillary, it is desirable to extend the life of the capillary by reducing wear during bonding or reducing adhesion dirt, but by reducing the [111] orientation of the body region, the life can be reduced. Prolongs the effect. In addition, increasing the [111] orientation in the crystal grains in the outermost peripheral region increases the bonding strength, but also causes damage in the case of a pad electrode structure that is susceptible to damage. On the other hand, the damage to the pad electrode can be reduced by setting the [111] orientation of the body region to 40% or less.

  In the crystal grain structure of the cross section of the ball joint in the horizontal direction with the substrate surface, the total area ratio of crystal grains having [112], [113], [114] and [115] orientations with respect to all crystal grains is 3 to 40%. By using the ball joint portion in the range, it is possible to reduce damage to the chip or the electrode directly under the ball portion. In the case of an electrode structure or the like in which small ball joints, Cu wirings and low dielectric films are alternately formed, it is a problem to damage the chip or the inside of the electrode. In order to improve this, it is difficult to manage only the [111] and [100] orientations of the ball joint cross section, and the control of [112], [113], [114], [115] orientations, etc. is effective. I found out. If the total area ratio of the crystal grains having these three orientations is less than 3%, the effect of suppressing damage is not sufficient, and the performance of a general-purpose joining device or joining jig (capillary) is used. This is because it is difficult to stably realize more than 40% in mass production in consideration of variations and the like.

  Preferably, in the ball joint cross section, the sum of the area ratios of the [112], [113], [114], and [115] orientations is in the range of 3 to 40%, and the [111] orientation and [ When the area ratio of the crystal grains having the [100] orientation satisfies the above-described relationship, damage to the chip or the like can be reduced while keeping the shape of the ball portion in a perfect circle. For example, the area ratio of [111] / [100] is 1.1 or more, or the area ratio of crystal grains having [111] orientation and [100] orientation is 30 to 95%, [111] / [ By using the area ratio of [100] together with the crystal orientation condition such as 1.5 or less, a synergistic effect with these effects can be utilized.

  The above-mentioned petal-shaped ball deformation is less likely to be a problem due to the low occurrence frequency of conventional relatively large balls. However, the petal-shaped ball deformation is not suitable for future needs such as small ball bonding, electrode film change, and high-speed connection. There is a concern that productivity may be affected, such as stable ball deformation and reduction in bonding strength. In the conventional ball deformation evaluation method, such as the average value and deviation of the crimp diameter in the Y direction parallel to the ultrasonic application direction and the X direction perpendicular thereto, the deviation from the perfect circle is accurately evaluated. It is difficult. For example, even if the petal-like deformation in which the periphery of the ball is uneven is remarkable, the apparent deformation length in the X direction and the Y direction is often the same. By clarifying the ball deformation management criteria, the petal-like deformation can be reduced, and the performance of the bonding wire composed of the structure according to the present invention and the bonding wire capable of forming the ball portion can be realized. An evaluation method for ball deformation is also important for use.

  Specifically, when the length of the line segment passing through the center of gravity of the cross section of the ball joint portion is d, the average value M and the standard deviation SD when the length d is measured at three or more arbitrary locations in the cross section. If the relationship is a bonding wire that satisfies SD / M ≦ 0.3, productivity can be improved by suppressing the protrusion of the ball from the pad opening and stabilizing the bonding strength. . Here, by measuring three or more line segments passing through the center of gravity, it is possible to grasp the degree of petal-like ball deformation, and it is sufficient to satisfy the relationship SD / M ≦ 0.2. This is because circularity is obtained and good ball bondability can be secured. Preferably, if SD / M ≦ 0.15, the roundness is even higher, and good results can be obtained even with small ball bonding with a pitch of 50 μm or less.

  The value of the bonding strength at the bonding portion between the ball portion and the electrode portion depends on the bonding area and the growth of the intermetallic compound phase at the bonding interface. The intermetallic compound here is a compound produced by the mutual diffusion of the main constituent components of the bonding wire and the main constituent components of the electrode section. Up to now, it has been known that an Au—Al compound phase is formed at the bonding interface between the Au wire and the Al electrode, and loads, ultrasonic vibrations, heating, etc. are performed to promote the phase growth. . However, the relationship between compound growth and wire material is not known, and in 4N high-purity Au, the difference in compound growth due to a small amount of added elements is small, and only the hardness of the ball part has been studied. . It was confirmed that by using the bonding wire capable of forming the ball bonding portion and the structure of the ball portion, the crystal orientation, etc. of the present invention, the growth of the intermetallic compound phase at the bonding interface is promoted, and the bonding strength can be stably increased. It was.

  That is, at the bonding interface between the ball portion and the substrate electrode portion, a gold bonding wire in which the formation ratio of the intermetallic compound composed of the main constituent component of the bonding wire and the main constituent component of the electrode portion is 65% or more of the entire bonding interface. If there is, it is possible to increase the bonding strength and increase the mass production productivity, or to improve the long-term reliability of the bonded portion when the semiconductor is used. Here, if the compound formation ratio is 65% or more of the entire bonding interface, it can sufficiently cope with future high-speed bonding, small ball bonding, and the like. Preferably, when the compound formation ratio is 75% or more, the yield of low-temperature bonding to the substrate can be improved. More preferably, if the formation ratio of the compound is 85% or more, the long-term reliability of the joint can be improved by suppressing voids, cracks and the like even in a high temperature use environment or high temperature operation of a high frequency IC.

  For example, a bonding wire having a [111] / [100] area ratio of 1.1 or more in the ball section, a bonding wire having a [111] orientation area ratio of 35% or more, or a cross section of the ball bonding section. If the bonding wire has an area ratio of [111] / [100] of 1.1 or more, it is relatively easy to increase the formation ratio of the intermetallic compound described above to 65% or more of the entire bonding interface.

  Regarding compound formation, it is also effective to control the distribution in addition to the above average control over the entire bonding interface. When the portion from the center of the cross section of the ball joint in the horizontal direction to the substrate surface to 1/2 of the joint ball radius D is the central portion and the periphery is the outer peripheral portion, the compound formation ratio at the central portion is 75% or more. If it is a bonding wire, the production yield in the narrow pitch connection of 45 micrometers or less can be raised. In addition, if the bonding wire has a compound formation ratio of 70% or more at the outer peripheral portion, the bonding interface is the main cause of lowering the mass productivity at a low temperature connection of 160 ° C. or lower suitable for the use of substrates, tapes, etc. It is advantageous to reduce the peeling failure.

  A semiconductor device for connecting an electrode part on a semiconductor substrate and an external terminal by using a bonding wire capable of forming a ball joint part of the crystal orientation described above, and having a narrow pitch joint characterized by the structure of the ball joint part described above It can cope with high-density mounting. That is, there are five types of features of the structure of the ball joint in this case. Specifically, (a) Of the crystal orientations in the vertical direction of the cross section in the cross section of the ball joint in the horizontal direction with the substrate surface, [100] The ratio of the area of crystal grains having [111] orientation to the area of crystal grains having orientation is 1.1 or more, (b) crystal grains having [111] orientation and [100] orientation with respect to all crystal grains (C) When the portion from the center of the ball joint section to 1/2 of the joint ball radius D is the core, the [100] orientation in the core is The ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having is 3 or less, (d) a portion outside 2/3 of the bonding ball radius D from the center of the ball bonding section cross section When the outer periphery The ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation is 0.9 or more, (e) [112], [113], [ 114] and [115], the total area ratio of the crystal grains having the [115] orientation is in the range of 3 to 40%.

  Here, the material of the electrode part and the external terminal used in the semiconductor device of the present invention is aluminum alloy (Al-Si, Al-Si-Cu, Al-Cu, etc.), copper and copper alloy, gold, palladium, etc. desirable. The connection form of wire bonding is applied to a connection form for forming a loop, a stud bump form for cutting a wire in the vicinity of a ball joint portion, and the like. In addition, when connecting two semiconductor substrates, the external terminals can be replaced with electrode portions on the semiconductor substrate.

  There are several means for forming the ball joint or the structure of the ball described above. Specifically, it is confirmed that the structure of the wire itself before ball formation, the ball forming method, the ball bonding method, etc. are effective. did.

  As one of the means for controlling the structure of these ball joints, it has been found that it is effective to control the solidified structure of the ball part formed by electric discharge at the wire tip.

  In the crystal grain structure of the wire longitudinal cross section of the ball portion, the area ratio of [111] / [100] is 1.1 or more, so that the ball joint portion connecting the ball portion on the electrode has an elliptical shape. Deformation can be suppressed, and a ball joint with good roundness can be obtained. The reason why the area ratio of [111] / [100] in the ball part is in the range of 1.1 or more is that when a load or ultrasonic vibration is applied to the ball part less than 1.1, elliptical deformation occurs. It is because it is easy to do. Preferably, the area ratio of [111] / [100] is more preferably 1.4 or more. If this area ratio is 1.4 or more, contamination of the organic film on the electrode surface due to the wafer manufacturing process, even in the case of a thick oxide film, etc. Deformation defects can be suppressed and the roundness of the ball joint can be maintained. More preferably, by setting the area ratio of [111] / [100] to 1.8 or more, the effect of promoting the deformation of the ball can be further enhanced, and the ball portion before joining to the wire diameter W can be improved. This also leads to an improvement in productivity in joining small balls having a diameter D ratio D / W of about 1.3 to 1.8. Moreover, there is no restriction | limiting in particular about the upper limit of the area ratio of [111] / [100], but if it is less than 40, stable manufacture is comparatively easy.

  Further, in the crystal grain structure of the wire section in the longitudinal direction of the wire, when the area ratio of the crystal grains having the [111] orientation with respect to all crystal grains is 35% or more, the ball part is formed deviated from the center of the wire. It is possible to suppress a defect due to misalignment such as, and to improve the roundness in the ball joint portion in which the ball portion is connected to the electrode. Here, the reason why the area ratio of the crystal grains having the [111] orientation is in the range of 35% or more is that the misalignment type defects increase. Preferably, the area ratio of the [111] orientation is 50% or more. This is because if the area ratio of the [111] orientation is 50% or more, the defect occurrence rate of misalignment can be reduced even if the bonding speed is increased, and thus productivity can be improved by high-speed bonding. . More preferably, when the ratio is 70% or more, a misalignment failure occurs when forming a small ball having a ratio D / L of the diameter D of the ball part before joining to the wire diameter L of about 1.3 to 1.8. Can be reduced.

  In the crystal grain structure of the wire longitudinal section of the ball portion, in addition to the above conditions, when the central region is from the center of the ball portion to 1/2 of the ball radius R, the crystal orientation of the wire longitudinal direction in the central region is Among them, the area ratio Rd of [111] / [100] and the area ratio Ra of [111] / [100] in the entire ball cross-section are | 1-Rd / Ra | ≦ 3. It is possible to reduce defects in which the ball joint is deformed into petals or irregularities. Here, if the value is more than 3, the petal-like unevenness phenomenon may be prominent on the periphery of the ball due to uneven stress distribution when the ball is grounded and deformed at high speed on the electrode. Preferably, if | 1-Rd / Ra | ≦ 1.5, the effect of suppressing petal-like deformation is enhanced even when the impact load or ultrasonic vibration is large.

  Regarding the cross-sectional structure of the ball part and the cross-sectional structure of the ball joint part, the above-mentioned desirable crystal orientations and the like have been described. However, by making them compatible with each other, defects such as abnormal deformation, peeling, and strength reduction during ball joining are suppressed. The overall productivity can be improved by increasing the effect of increasing the yield and increasing the manufacturing margin. Since the ball portion is subjected to impact load, rotation of the crystal orientation, etc. during deformation applying ultrasonic waves, the structure of the ball joint is changed from the solidified structure of the ball before deformation. Therefore, a synergistic effect is often obtained by controlling the cross-sectional structures of both the ball portion and the ball joint portion.

  For example, in the case of a bonding wire, the [111] / [100] area ratio of the ball section is 1.1 or more and the [111] / [100] area ratio of the ball joint section is 1.1 or more. In order to obtain a good perfect circular shape, the range of application such as wire diameter, ball diameter, ball joint size, etc. is expanded, and it can be applied to various package forms such as narrow pitch connection from the current general-purpose structure. Such a synergistic effect can be confirmed by each combination of the cross-sectional structure of the ball portion and the cross-sectional structure of the ball joint portion described above. Further, the bonding is performed such that the area ratio of [111] / [100] of the ball section is 1.1 or more and the total of [111] and [100] area ratio of the cross section of the ball joint is in the range of 30 to 95%. In the case of a wire, it is possible to obtain ball deformation with good roundness in a wide range of wire diameters of 15 to 30 μm.

  Regarding the structure of the gold bonding wire, in the longitudinal section of the wire part excluding the affected part, the center part (c), the inner layer part (g), and the outer layer that are divided from the center of the wire into 1/3 of the wire radius L When the area ratio of [111] / [100] related to the crystal orientation in the wire longitudinal direction in the part (s) is Lc, Lg, and Ls, respectively, the relationship of Lc ≦ 3, Lg ≧ 0.8, and Ls ≧ 0.5 If the gold bonding wire satisfies at least two of the above, it is easy to control the cross-sectional structure of the ball part and the cross-sectional structure of the ball joint part, and the loop controllability can be improved. it can. To satisfy wire wedge bonding, ball melt formation, solidification of the ball by heat conduction in the longitudinal direction of the wire, straight upright of the ball, control of the loop shape, linearity, etc. It was confirmed that it was effective to divide into the outer part and the outer layer part and pay attention to the relationship with the tissue in each part. Here, the reason why Lc, Lg, and Ls are set in the above-described range is, for example, that the area ratio Lc ≦ 3 of [111] / [100] in the center is that the structure control during solidification of the ball is In addition, by setting the area ratio Lg ≧ 0.8 of [111] / [100] in the inner layer portion, it is effective to satisfy the above-described crystal orientation relationship and the like in the above-described ball joint cross section. In addition, by setting the area ratio Ls ≧ 0.5 of [111] / [100] of the outer layer part, it becomes possible to stably control the loop shape without adversely affecting the ball part and the ball joint part. This is because effects such as the above can be obtained. Preferably, the three types of area ratios of Lc, Lg, and Ls satisfy the above range at the same time, so that a higher effect of controlling the structure of the ball portion and the ball joint portion described above can be obtained.

  The crystal orientation in the present invention is such that the angle difference of the crystal orientation with respect to the longitudinal direction of the wire is within 10 ° in each of the ball portion and the ball joint portion. This is because, within this range, it has the characteristics of each crystal orientation, and the degree of influence on the various characteristics of the bonding wire can be effectively utilized. When the angle difference of crystal orientation exceeds 10 °, This is because there is a concern that a difference occurs in the influence on the wire characteristics.

  In the crystal grains in the cross section, if the crystal grain boundary in which the angle difference between the orientations of adjacent crystal grains is 30 ° or less is a bonding wire in which the ratio of the total crystal grains to the grain boundary is 50% or more, the bonding partner The influence of the surface property of the electrode material can be reduced, the isotropic deformation of the ball joint can be improved, and the joint strength can be increased. This is because when the ball is deformed, if the surface of the electrode material is slippery, the ball deformation anisotropy will increase, or if the indentation of the probe is large or the joint strength decreases due to the large number of indentations Is concerned. On the other hand, it has been found that a crystal grain in which the angle difference between the orientations of adjacent crystal grains is 30 ° or less can enhance the effect of deformation in almost the same direction, and the grain boundary occupies the grain boundary of all crystal grains. By setting the ratio to 50% or more, even when the above-mentioned slippery electrode or probe indentation is large, the roundness of the ball joint is improved, and the destruction of the oxide film on the Al surface is promoted. The effect of increasing the strength is further enhanced. Preferably, if the ratio of the crystal grain boundaries where the angle difference between the orientations of adjacent crystal grains is 30 ° or less is 70% or more, the correspondence to the surface properties of the electrode material can be further improved.

In addition to controlling the crystal orientation such as the [111] orientation or the [100] orientation described above, the number of crystal grains per unit area is greatly involved in reducing variations in the ball joint shape, ball deformation, and the like. I found out. That is, it is desirable that the number of crystal grains in the cross section of the ball portion or the ball joint portion is 0.005 to 0.1 / μm ² . Here, the reason for the above range of the number of crystal grains is that when the number of crystal grains is less than 0.005 / μm ² , the coarse crystal grains of the ball part induce deformation anisotropy, and This is because the deviation becomes large, and it is difficult to realize ultrafine crystal grains of more than 0.1 / μm ² uniformly over the entire wire in a normal bonding wire manufacturing process. Furthermore, among the crystal orientations in the wire longitudinal direction, the area ratio of [111] / [100] is 1.1 or more, and by making the number of crystal grains in the above range, the effect of increasing the bonding strength can be further enhanced.

  In order to reduce variations in the shape of the ball joint, ball deformation, and the like, it is desirable that the standard deviation of the crystal grain size in the wire longitudinal cross section is 1.5 μm or less in the ball or ball joint. Here, the reason for the range of the crystal grain size is that if it exceeds 1.5 μm, the shape of the ball joint portion is stabilized, but there is a concern that the chip may be damaged.

  The texture of gold bonding wires has not been known so far and no reports have been found. Although the textures of various metals are known for rolled materials, drawn fine wires, etc., there is a unified view on the metal processing method, the relationship between components and texture, and the relationship between texture and member performance. Is not obtained. In the conventional method for measuring the texture, X-ray diffraction, electron beam diffraction by TEM, and the like are used. However, a ball portion formed at the tip of a gold bonding wire and a ball joint portion connected to the electrode are used. As described above, it is difficult to measure the texture in a fine region having a diameter of about several tens of μm.

  Advances in analysis technology are remarkable, and micro-area X-rays that can narrow down the measurement area and the recently developed Electron Back Scattering Pattern (EBSP) method are used to measure the texture of fine samples. It is a very effective measuring means. In particular, a technique for measuring the texture of the polished cross section of the ball portion formed at the tip of the gold bonding wire with high accuracy and relatively easily by EBSP measurement has been established.

  The EBSP method is also effective for analyzing the texture of the ball joint, and FIGS. 2 and 3 show examples of the results of EBSP measurement of the ball joint. For example, FIG. 2 shows an example of crystal grains in a cross section of the ball joint portion in the horizontal direction with respect to the substrate surface as EBSP measurement of the ball portion formed at the tip of a gold bonding wire having a wire diameter of 23 μm. FIG. 3 shows an inverted pole figure regarding the crystal orientation in the direction perpendicular to the cross section of the ball surface in the horizontal direction with respect to the substrate surface. 3A corresponds to the result when the ratio of [111] is large, FIG. 3B corresponds to the result when there are many [100], and FIG. 3C corresponds to the result when there are many orientations such as [211]. At the ball joint, it is more difficult to prepare a measurement sample, and it is necessary to ensure cross-sectional polishing with less distortion, ensuring conduction to suppress charge-up, and the like. Until now, the structure and crystal orientation of the ball joint have not been reported, and the structure analysis becomes possible only after such a sample preparation technique is established.

  FIG. 4 shows an example of the result of the EBSP measurement of the ball joint, assuming that the crystal grains in the outermost peripheral region are connected in layers. The wire diameter is 23 μm gold bonding wire, and the initial ball diameter is 48 μm. The figure shows (a) a grain boundary, (b) an inverted pole figure of the outermost peripheral region, and (c) an inverted pole figure of the entire ball joint. When (b) and (c) are compared, there are many [111] at the outermost periphery, but when averaged over the entire ball, it is rather shown that there are many [100] orientations.

  For the first time by utilizing such latest analysis technology, the crystal orientation of each fine crystal grain, the distribution of crystal orientation in the entire cross section, etc., regarding the microstructure of the ball part or ball joint part of the gold bonding wire Can be measured with high accuracy and good reproducibility. It should be noted that a highly accurate orientation analysis can be performed for the first time by optimizing many experimental conditions such as sample preparation and device operation.

  In the manufacturing method of the wire that controls the crystal orientation of the ball part and the ball joint part, it is necessary to stabilize the structure. For that purpose, a uniform structure and component distribution must be realized in the longitudinal direction and the circumferential direction of the wire. Is the point. If the crystal orientation of the ball portion or ball joint portion according to the present invention is partially obtained, a normal wire may be possible. However, in order to stably control the required crystal orientation at mass production level and achieve it easily and reproducibly, it is necessary to optimize the manufacturing process such as rolling, wire drawing, and heat treatment at the final wire diameter. I found it effective.

  In the step of performing heat treatment while sweeping the wire continuously using a horizontal heating furnace such as infrared heating or resistance heating, the temperature is in the temperature range of 0.5 to 1.7 times the recrystallization temperature of the wire, It is effective that the soaking area that is within a temperature difference of 50 ° C. in the longitudinal direction of the wire is 15 cm or more and the inner diameter of the heating tube is 200 times or more of the wire diameter. This heating promotes the reduction of temperature variations in the longitudinal and radial directions of the wire.

  When a wire having a relatively large wire diameter (wire diameter: 20 to 1 mm) is repeatedly rolled and drawn a plurality of times, it is processed by rotating the wire by 10 ° or more at half or more of the number of times of processing. It is effective to promote uniforming of the structure in the circumferential direction of the wire by adding processing distortion, dislocation, etc. on the wire surface uniformly or randomly in a concentric shape of the line cross section.

  For wire drawing with a relatively small wire diameter (wire diameter of 2 to 0.01 mm), the wire enters and exits into the hole of the wire drawing die at an angle of 20 ° or less, and the wire before and after the wire is straight. When is 15 cm or more, the effect of uniformly processing distortion in the circumferential direction of the wire is enhanced.

  A certain degree of effect can be obtained by individually performing the above-described processing, wire drawing, heat treatment, etc., and further, by combining them, the longitudinal direction of the wire, the structure in the circumferential direction, the component distribution is made uniform, The effect of controlling the crystal orientation of the required ball portion and ball joint portion can be further enhanced.

  The addition of elements in the wire also works effectively to control the structure of the ball part and the ball joint part. A component system that makes the above-described structure control relatively easy will be described later, although the effect of addition of elements also changes in consideration of manufacturing techniques such as melting, wire drawing, and heat treatment during wire manufacturing.

  The main component is Au, and the additive components are: Be: 0.0001 to 0.0006% by mass, Ca: 0.002 to 0.005% by mass, Eu: 0.001 to 0.004% by mass, Nd: 0.0. 001-0.004 mass%, Yb: 0.0001-0.001 mass%, Cu: 0.001-0.4 mass%, Pd: 0.002-0.6 mass%, Ag, Mn, Pt By using a gold alloy bonding wire containing 0.001 to 0.2% by mass of one or more kinds, as described above, the overall ratio of [111] and [100] in the ball bonding portion is controlled, and the core portion. Alternatively, by controlling the area ratio of [111] / [100] at the outer peripheral part or the ratio of [111] and [100] in the ball part formed at the wire tip, etc. Such as the roundness and bonding strength of ball joints Above it is achieved. Here, by adding elements such as Be, Ca, Eu, Nd, Yb, Cu, Pd, Ag, Mn, or Pt in the above concentration ranges, each element effectively exhibits a synergistic effect, and the ball It becomes possible to control the structure at the joint and the ball joint. If each element is below the above-mentioned minimum concentration, its effect is small, and if it exceeds the maximum concentration, bondability is impaired due to oxidation or shrinkage formation at the time of ball formation, loop controllability etc. Therefore, the above concentration was selected.

  Using the gold bonding wire according to the present invention described above, ball bonding and wedge bonding are repeatedly performed on the electrode portion formed on the semiconductor chip and the substrate, and the gold bonding wire is connected to connect the electrode portion and the bonding wire. In this method, a ball portion is formed by arc discharge at the end of the bonding wire after being wedge-bonded to the electrode portion of the substrate, and when the ball portion is bonded to the electrode portion on the semiconductor chip, the original wire diameter is set. When it is 2L, the angle with respect to the wire longitudinal direction with respect to the wire end having a length of 0.8L to 4L of the deformed end where the wire diameter after wedge bonding is 10% or more thinner than the original diameter A gold bonding wire characterized by forming a ball portion having a radius of 1.2 L to 2.0 L by performing arc discharge from a direction in which the angle is 0 to 45 ° The connection method is preferable.

  It was confirmed that the wire end portion after the wedge bonding was bent by an impact or the like at the time of breakage, and that when the bent portion became long, misalignment, irregular shape, and the like were likely to occur when the ball portion was formed. The reason why the bent portion is in the above range is that a portion where the wire diameter after wedge bonding is 10% or more smaller than the original diameter is a deformed end portion, and the length of the deformed end portion is suppressed to less than 0.8L. This is because it is difficult to balance with the capillary shape, and if it exceeds 4L, the center of the ball part, the deviation from the true sphere, and the like become remarkable. Further, if the angle between the wire longitudinal direction and the arc discharge is 0 to 45 °, it is easy to form a good ball in which the ball portion is located at the center of the wire. If it is less than 2L, it is difficult to suppress the defect that the eccentricity of the ball part is generated due to the deformation end, and if the ball diameter is more than 2.0L, the amount of deformation of the ball at the time of joining is small. This is because it becomes difficult to join small balls for narrow pitch.

  Examples will be described below.

  By using electrolytic gold having a gold purity of about 99.95% by mass or more, a mother alloy containing each additive element group was individually melted and cast in a high-frequency vacuum melting furnace to melt the mother alloy. A predetermined amount of the master alloy of each additive element thus obtained and electrolytic gold having a gold purity of about 99.995% by mass or more are melt-cast in a high-frequency vacuum melting furnace, the ingot is rolled, and then drawn at room temperature. If necessary, an intermediate annealing step of the gold bonding wire is added, and further wire drawing is performed to obtain a gold bonding wire having a final wire diameter of 23 μm, followed by continuous annealing in the atmosphere, and an elongation value of about 4 % Was adjusted.

  For connection of the gold bonding wire, a general-purpose automatic wire bonder apparatus was used to perform ball / wedge bonding. In ball bonding, a ball portion was formed at the wire tip by arc discharge, and the ball portion was bonded to an electrode film by thermocompression bonding using ultrasonic waves. Further, the other end of the wire was wedge-bonded to the lead portion on the lead frame or the BGA substrate. In order to investigate the applicability to the narrow pitch connection which is a future need, a narrow pitch connection with an electrode interval of 50 μm or 40 μm was performed.

  The bonding partner is an Al alloy film (Al-1% Si, Al-0.5% Cu, Al-1% Si-0.5%) having a thickness of about 0.8 μm, which is a material of an electrode film on a silicon substrate. Cu) was used. On the other hand, a lead frame with Ag plating (thickness: 1 to 4 μm) on the surface or a resin substrate with Au plating / Ni plating / Cu wiring formed on the surface is used as a partner for wedge bonding. did.

  In order to evaluate the shape of the ball bonding portion, the ball portion was bonded to an electrode film on a silicon substrate at a stage temperature of 180 ° C. With 100 ball joints, ultrasonic application and the crimping diameter in the parallel direction were measured with an optical microscope, and an average value and a standard deviation were obtained.

In the anisotropy evaluation of the ball deformation, for the 100 ball joints, the ball joints are observed from the direction perpendicular to the electrodes, and are straight lines connecting points that pass through the center of the wire and contact the outer peripheral part. The longest side length (D _L ) and the short side length (D _S ) were measured for the maximum and the minimum. The ratio (D _L / D _S −1) was calculated as an anisotropy parameter, and the average value was obtained. It can be determined that the closer the value of this anisotropy parameter is to 0, the better the roundness, and the greater the value, the more remarkable the flatness, anisotropy, and the like.

  In order to examine the shape of the ball portion, a ball having a diameter of 42 μm was formed with a wire having a diameter of 23 μm, and 10 ball portions were observed with a light microscope or SEM. When one or more obvious misalignments are observed with respect to the misalignment formed by inclining the ball part from the center of the wire, it is determined that the ball part is defective when the occurrence of one or more obvious misalignment is observed. In this case, it was judged that there was no problem, and a mark “◯” was given, and a case where no misalignment was observed was good, so that it was good.

  In order to investigate the occurrence of an abnormal shape of the ball joint, a ball joint having an average of the joint ball diameter of about 55 μm was formed with a 23 μm diameter wire, and the ball joint was observed with a light microscope. Above all, the evaluation was made by paying attention to elliptical, petal-like irregularities, eccentricity and the like.

  Observe 1000 ball joints with a light microscope, determine that there are 3 or more elliptical ball joints as defective, evaluate the occurrence of ellipses with x marks, and 1 to 2 minor elliptic deformations In the table, the symbol “◯” indicates the occurrence of the occurrence, and the symbol “◎” indicates the absence of the occurrence. In addition, regarding the petal-like irregularities, a case where remarkable petal-like deformation is recognized at four or more ball joints is judged as bad, and a case where 1 to 3 small petal-like deformations occur If it does not occur, it is marked with ◎ and shown in the column of petal deformation in the table.

  With respect to the eccentricity failure, 2,000 ball joints are observed with an optical microscope, and the center of the ball joint is regarded as eccentric when the deviation from the center of the wire immediately above is 10 μm or more. When the occurrence of eccentricity is 3 or more, it is indicated by x, when it is 1 to 2 occurrences of eccentricity, it is indicated by ◯, and when it is not generated, it is indicated by ◎.

  In addition, when observing 500 ball joints with a light microscope and determining the displacement due to deformation of the ball joints, the displacement of the center of the ball joint from the target point is 10 μm or more. When the number of defects is 3 or more, it is indicated by x, when it is 1-2, it is indicated by ○, and when it does not occur, it is indicated by ◎.

  The length d of the line passing through the center of gravity of the cross section of the ball joint is taken as d, and the average value M and standard deviation SD when the length d is measured at any three or more locations of the cross section are obtained, and the numerical value of SD / M is calculated. did.

  In the evaluation of damage to the chip, the ball part was bonded onto the electrode film, the electrode film was dissolved, and the damage to the insulating film or the silicon chip was observed by SEM. The number of electrodes was observed at 1000 locations. If no damage is found, ◎ mark, if there are 2 or less cracks of 1 μm or less, it is judged that there is no problem, ○ mark, if 1 crack or more of 1 μm or more and less than 5 μm is 1 or more, it is judged as a level of concern If there are 1 or more cracks or crater breakage of 5 μm or more, it is judged that the level is a concern and is indicated by an X mark.

100 initial shear strength measurements of the ball joint were performed, the average value was obtained, the area of the ball joint was obtained, and the joint strength per unit area was calculated. Bonding strength per unit area is equal to or 10 kg / mm ² or more ◎ indicia, 8~10kg / mm be in the range of ² no problem level determined to ○ marks, bonding is less than 8 kg / mm ² Judging from the fact that the strength was insufficient, it was indicated by a cross.

In addition, using a pad electrode having three or more probe indentations, 50 initial shear strength measurements of the ball joint are performed, an average value is obtained, and an area of the ball joint is obtained to obtain a bond per unit area. Intensity was calculated. Bonding strength per unit area is equal to or 9 kg / mm ² or more ◎ indicia, 7~9kg / mm be in the range of ² no problem level determined to ○ marks, bonding is less than 7 kg / mm ² Judging from the fact that the strength was insufficient, it was indicated by a cross.

  In order to evaluate the long-term reliability of the bonded portion, the ball portion at the tip of the gold bonding wire was bonded to the electrode, and after bonding the gold bonding wire, the whole was sealed with an epoxy resin to produce a semiconductor device. The semiconductor device was heat-treated at 125 ° C. for 1000 hours or 150 ° C. for 1000 hours. Thereafter, a part of the sealing resin was removed using a commercially available opening device, and the average value of the shear strength at 50 joints was obtained. Reliability was judged by whether or not the bonding strength after the heat treatment was lower than the initial bonding strength before the heat treatment. When the strength does not decrease up to 1000 hours at 150 ° C., the reliability is good, so it is indicated by ◎, and when the bonding strength is reduced after 1000 hours at 125 ° C., it is indicated by ×, In the case of, it is indicated by a circle.

  Three types of pads A, B, and C having different pad structures were prepared. Both the pads A and B are made of Al-0.5% Cu. The pad A is a case where a thick aluminum oxide film is formed on the surface. The pad B is a contaminated layer such as an organic film or a fluoride film on the aluminum surface. Is relatively thick. The pad C is a case where the material is Cu and Cu is exposed on the surface. Using pads A, B, and C, 20,000 bondings were performed at a stage temperature of 170 ° C., and the number of peeling (non-sticking number) was measured at the time of bonding. Therefore, if the number of non-sticky is 1 to 5 or less, it is judged that it can be sufficiently handled by optimizing the joining conditions. . Moreover, the chip | tip damage showed the result observed by the method mentioned above using the pad A. FIG.

  Capillary life measurement is performed with 100,000 continuous bonds, and the tip of the capillary used is observed with a light microscope. However, since it is good when there is little dirt and wear on the capillary, it is marked with ◎, and the middle is marked with ○.

  In Table 1-1 to Table 1-3, the gold bonding wires according to the first claim are Examples 1 to 12, and the gold bonding wires according to the second claim are Examples 1 to 5, 7, and 9 to 12. The gold bonding wires according to the third claim are Examples 1-4, 6-8, 10-15, and the gold bonding wires according to the fourth claim are Examples 2-10, 12-14. The gold bonding wires according to the seventh claim are examples 1 to 9, 12, 14 and the gold bonding wires according to the eighth claim are the examples 1 to 10, 12, and the gold bonding wires according to the ninth claim. Examples 1 to 15, gold bonding wires according to the 10th claim are Examples 1 to 11, 13, and 14, gold bonding wires according to the 11th claim are Examples 1 to 7, 9 to 12, 14, 15, 12 claims The gold bonding wires according to the first to fourth, sixth to eighth, 10 to 15, and the fifteenth claim are the second to eleventh, thirteen to fifteenth, thirteenth, fourteenth and fourteenth embodiments. The gold bonding wires according to claims 16 and 17 correspond to the first to fifteenth embodiments.

  Tables 2 and 3 show the results of the structure of the ball part and the ball joint part when the composition of the gold bonding wire and the ball forming conditions are changed.

  In Table 2, the gold bonding wires according to the 18th claim are Examples 16 to 29, and Comparative Examples 4 to 6 are cases where the 18th claim is not satisfied. In Table 3, the gold bonding wires according to the 19th claim are Examples 30 to 37, and Comparative Examples 7 and 8 satisfy the 18th claim but do not satisfy the 19th claim. Corresponds to a case where both the 18th and 19th claims are not satisfied.

  In Tables 4-1 and 4-2, the gold bonding wires according to the fifth claim are Examples 38 to 46, and the gold bonding wires according to the sixth claim are Examples 38 to 43.

  A part of the evaluation results will be described for representative examples of each claim.

  The bonding wires of Examples 1 to 12 have a strong effect of suppressing elliptical deformation because the area ratio of [111] / [100] in the ball joint according to the present invention is 1.1 or more. It was confirmed that the roundness of the joint was high.

  The bonding wires of Examples 1 to 5, 7, 9 to 12, 14, and 15 have an area ratio of crystal grains having [111] orientation and [100] orientation in the ball joint according to the present invention of 30 to 95%. By being in this range, the effect of suppressing the eccentricity of the ball joint portion was sufficient, and the roundness of the ball joint portion was improved.

  The bonding wires of Examples 1 to 4, 6 to 8, and 10 to 15 have an area ratio of [111] / [100] in the core portion up to ½ of the ball radius D in the ball joint portion according to the present invention. Is 3 or less, the positional deviation of the joint portion is reduced, which is advantageous for connection to a small pad portion. In Examples 1 to 4, 6 to 8, 10 to 12, 14, 15 and the like, the area ratio of [111] / [100] in the core is 3 or less, and [111] / [100]. Or the area ratio of the crystal grains having the [111] orientation and the [100] orientation satisfies the range of 30 to 95%, whereby the growth rate of the compound Was as high as 70% or more, which was confirmed to be advantageous for securing the bonding strength.

  In the bonding wires of Examples 2 to 10 and 12 to 14, the area ratio of [111] / [100] is 0. 0 in the outer peripheral portion on the outer side from the position 2/3 of the bonding ball radius D according to the present invention. It was confirmed that by being 9 or more, the effect of suppressing the petal-like deformation and enhancing the effect that the crystal grains of the outer peripheral portion deform almost uniformly is strong.

  The bonding wires of Examples 1 to 9, 12, and 14 have a total area ratio of [112], [113], [114], and [115] directions in the ball joint according to the present invention of 3 to 40%. It was confirmed that the damage to the chip or the electrode directly under the ball part can be reduced by being in the range.

  The bonding wires of Examples 1 to 10 and 12 have an anisotropy parameter SD / M determined from the shape of the ball joint according to the present invention of 0.3 or less. It was confirmed that a ball joint having a high roundness and a high effect of suppressing defects such as deformation was obtained.

  In the bonding wires of Examples 1 to 11, the elliptical deformation is suppressed by setting the area ratio of [111] / [100] in the ball portion formed at the wire tip according to the present invention to 1.1 or more. It was confirmed that the effect was strong.

  The bonding wires of Examples 1 to 7, 9 to 12, 14, and 15 are displaced from the wire center by setting the area ratio of crystal grains having [111] orientation in the ball portion to 35% or more according to the present invention. As a result, it was confirmed that the roundness was sufficiently improved by reducing the eccentricity of the ball joint portion connected to the electrode by reducing the misalignment phenomenon in which the ball portion was formed. .

  In the bonding wires of Examples 1 to 7 and 9 to 12, the area ratio Rd of [111] / [100] in the central area in the ball portion and [111] / [100 in the entire ball cross section according to the present invention. And the area ratio Ra of | 1-Rd / Ra | ≦ 3, the ball joint formed by connecting the ball portion on the electrode is deformed into a petal shape or an uneven shape. It has been confirmed that the number of defects can be reduced.

  The bonding wires of Examples 1 to 15 are [111] / [100] in the center portion, the inner layer portion, and the outer layer portion obtained by dividing the longitudinal section of the wire portion into three for every 1/3 of the wire radius L according to the present invention. When the area ratios of Lc, Lg, and Ls are Lc ≦ 3, Lg ≧ 0.8, and Ls ≧ 0.5, satisfying at least two of the relationships, the ball forming conditions and the bonding conditions However, it is easy to stably control the structure of the ball part and the ball joint part. As a result, the roundness of the ball joint part is improved, the uprightness of the ball directly above, and the loop shape. The effect of satisfying control, linearity, etc. is enhanced.

  The bonding wires of Examples 38 to 46 are the outermost peripheral region that is an outer portion from 4/5 of the ball radius D in the ball joint according to the present invention, or the outermost crystal grains included in the outermost peripheral region. In at least one of the above, when the total area ratio of the crystal grains having the [111] orientation is 50% or more, the pads A, B, and C, which are difficult to bond, have good bondability, and 60 In the case of% or more, the bonding property was improved in the pads A, B and C.

  In the bonding wires of Examples 38 to 43, the area ratio of the [111] orientation in the outermost peripheral region according to the present invention is 50% or more, and the [111] orientation is present in the body region other than the outermost peripheral region. When the total area ratio of the crystal grains is 40% or less, the capillary life is improved.

  In Comparative Examples 1 to 3, the present invention was not satisfied, and all the characteristics such as the roundness of ball deformation, misalignment, and shear strength were not sufficient, and a practical problem was confirmed.

  In the bonding wires of Examples 2 to 11 and 13 to 15, the proportion of the crystal grain boundaries in which the angle difference between the orientations of adjacent crystal grains is 30 ° or less according to the present invention is 50% of the grain boundaries of all crystal grains. % Or more, it was confirmed that sufficient roundness was ensured even with a pad electrode with many probe indentations, and as a result, it was easy to obtain good bonding strength.

  The bonding wires of Examples 16 to 29 satisfy the addition of the alloy element according to the sixteenth claim, and the relationship between the crystal orientation of the ball joint or the ball portion is as defined in claims 1 to 10 according to the present invention. At least one was satisfied. Here, the conditions of Example 30 were used for the discharge conditions. On the other hand, in Comparative Examples 4 to 6, the 16th claim was not satisfied, and the number of items that did not satisfy the present invention increased to two or more due to the crystal orientation of the ball joint or the ball.

  In the bonding wires of Examples 30 to 37, the ball forming method according to the seventeenth aspect is satisfied, and the relationship of the crystal orientation of the ball bonding portion or the ball portion is at least as defined in the first to tenth aspects according to the present invention. One was satisfied. On the other hand, in Comparative Examples 7 and 8, the 16th claim was not satisfied, and the number of items that did not satisfy the present invention increased to two or more due to the relationship of the crystal orientation of the ball joint or ball. In Comparative Examples 9 to 11, when the conditions of the present invention could not be satisfied for both the composition of the bonding wire and the ball forming method, the desired relationship of the ball joint or the crystal orientation of the ball portion could not be obtained.

Schematic diagram of ball bonding part of gold bonding wire (a) normal, (b) eccentricity, (c) petal shape Grain boundaries by EBSP measurement of ball joints of gold bonding wires Reverse pole figure of EBSP measurement of ball joint EBSP measurement result of ball bonding part of gold bonding wire (a) Grain boundary, (b) Reverse pole figure of outermost peripheral region, (c) Reverse pole figure of entire ball joint part

Claims (24)

  A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and a crystal grain having a [100] orientation among crystal orientations in a direction perpendicular to the cross section of the ball joint portion in a horizontal direction with respect to the substrate surface The ratio of the area of the crystal grains having the [111] orientation to the area of is 1.1 or more, and a gold bonding wire for a semiconductor device.   A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and a [111] orientation with respect to all crystal grains among crystal orientations in a direction perpendicular to the cross section in a cross section of the ball joint portion in the horizontal direction with respect to the substrate surface And an area ratio of crystal grains having a [100] orientation is in the range of 30 to 95%.   A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and the ball surface is bonded to the substrate surface in the horizontal direction within the crystal orientation in the vertical direction of the cross section in the cross section of the ball bonding portion in the horizontal direction with the substrate surface. When the portion from the center of the cross section to 1/2 of the joining ball radius D is the core, the ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation in the core is A gold bonding wire for a semiconductor device, which is 3 or less.   A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and the ball surface is bonded to the substrate surface in the horizontal direction within the crystal orientation in the vertical direction of the cross section in the cross section of the ball bonding portion in the horizontal direction with the substrate surface. The area of the crystal grain having the [111] orientation with respect to the area of the crystal grain having the [100] orientation in the outer peripheral portion when the outer portion from 2/3 of the joint ball radius D from the center of the cross section is the outer peripheral portion. A gold bonding wire for a semiconductor device, wherein the ratio is 0.9 or more.   A gold bonding wire in which a ball portion formed at an end is bonded to a substrate electrode portion, and the ball surface is bonded to the substrate surface in the horizontal direction within the crystal orientation in the vertical direction of the cross section in the cross section of the ball bonding portion in the horizontal direction with the substrate surface. The area of a crystal grain having a [111] orientation in at least one of the outermost peripheral region that is a portion outside 4/5 of the ball radius D from the center of the section and the outermost crystal grain included in the outermost peripheral region A gold bonding wire for a semiconductor device, wherein the total ratio is 50% or more.   An area of a crystal grain having a [111] orientation in the body region, wherein a region that does not belong to either the outermost peripheral region or the outermost crystal grain included in the outermost peripheral region in the ball joint cross section 6. The gold bonding wire for a semiconductor device according to claim 5, wherein the total ratio is 40% or less.   A gold bonding wire in which a ball part formed at an end part is joined to a substrate electrode part, and [112] with respect to all crystal grains in a crystal orientation in the vertical direction of the cross section in the cross section of the ball joint part in the horizontal direction with the substrate surface. A gold bonding wire for a semiconductor device, wherein the total area ratio of crystal grains having [113], [114], and [115] orientations is in the range of 3 to 40%.   When the length of the line segment passing through the center of gravity of the ball joint cross section is d, the relationship between the average value M and the standard deviation SD when the length d is measured at any three or more locations in the cross section is expressed as SD. The gold bonding wire for a semiconductor device according to claim 1, wherein /M≦0.3 is satisfied.   An intermetallic compound comprising a main component of a bonding wire and a main component of the electrode part at the bonding interface between the ball part of the gold bonding wire and the substrate electrode part obtained by bonding the ball part formed on the end part to the substrate electrode part The gold bonding wire for a semiconductor device according to any one of claims 1 to 8, wherein the formation ratio of is 65% or more of the entire bonding interface.   A gold bonding wire for forming a ball portion at an end, wherein a crystal grain structure having a [100] orientation in a crystal orientation in a wire longitudinal direction in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball portion. A ratio of the area of crystal grains having [111] orientation to the area is 1.1 or more.   A gold bonding wire that forms a ball portion at an end, and in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball portion, among the crystal orientations in the wire longitudinal direction, [111] orientation with respect to all crystal grains A gold bonding wire for a semiconductor device, wherein an area ratio of crystal grains is 35% or more.   A gold bonding wire that forms a ball portion at an end portion, and in a crystal grain structure of a cross section perpendicular to the wire longitudinal direction of the ball portion, a region from the center of the ball portion to 1/2 of the ball radius R is a central region , The ratio Rd of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation out of the crystal orientation in the longitudinal direction of the wire in the central region, and [100] in the entire ball cross section. 12. The semiconductor according to claim 10, wherein the ratio Ra of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the orientation is | 1−Rd / Ra | ≦ 3. Gold bonding wire for equipment.   In the crystal grain structure of the cross section in the longitudinal direction of the wire part excluding the heat-affected part of the gold bonding wire, the center part (c) and the inner layer part (g ), The ratio of the area of the crystal grain having the [111] orientation to the area of the crystal grain having the [100] orientation out of the crystal orientation in the wire longitudinal direction in the outer layer portion (s) is Lc, Lg, and Ls, respectively. A gold bonding wire for a semiconductor device satisfying at least two of the relationships of ≦ 3, Lg ≧ 0.8, and Ls ≧ 0.5.   14. The semiconductor device according to claim 1, wherein the crystal grains having the [111] orientation and the [100] orientation have an inclination of 10 ° or less with respect to the longitudinal direction of the bonding wire. Gold bonding wire.   In the crystal grains in the cross section, the ratio of the crystal grain boundaries in which the angle difference between the orientations of adjacent crystal grains is 30 ° or less is 50% or more of the grain boundaries of all crystal grains, 1 to 7, 10, 11. A gold bonding wire for a semiconductor device according to any one of 11 and 13. 14. The gold bonding wire for a semiconductor device according to claim 1, wherein the number of crystal grains in a cross-sectional structure of the ball part or the ball joint part is 0.005 to 0.1 / μm ² .   14. The gold bonding wire for a semiconductor device according to claim 1, wherein a standard deviation of a crystal grain size in a cross-sectional structure of the ball portion or the ball joint portion is 1.5 μm or less.   The main component is Au, and the additive components are: Be: 0.0001 to 0.0008 mass%, Ca: 0.001 to 0.005 mass%, Eu: 0.0005 to 0.004 mass%, Nd: 0.00. 0005 to 0.004 mass%, Yb: 0.0005 to 0.005 mass%, Cu: 0.001 to 0.4 mass%, Pd: 0.001 to 0.6 mass%, Ag, Mn, Pt The gold bonding wire for a semiconductor device according to any one of claims 1 to 17, wherein one or more of them are contained in an amount of 0.0005 to 0.2 mass.   Using the gold bonding wire for a semiconductor device according to any one of claims 1 to 18, ball bonding and wedge bonding are repeatedly performed on an electrode portion formed on a semiconductor chip and a substrate, and the electrode portion and the bonding wire are connected. A method of connecting gold bonding wires to be connected, wherein a ball portion is formed by arc discharge at an end portion of the bonding wire, and when the ball portion is bonded to an electrode portion on a semiconductor chip, the original wire diameter is set to 2L. When the wire end is 0.8L to 4L, the angle with respect to the longitudinal direction of the wire is 0 to 45 degrees with respect to the wire end having a length of 0.8L to 4L. A gold bonding wire characterized in that arc discharge is performed in the direction of ° to form a ball portion having a radius of 1.2 L to 2.0 L and then bonded to the ball. Connection method.   A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and a crystal grain having a [100] orientation among crystal orientations in a vertical direction of the cross section in a ball joint cross section in the horizontal direction with the substrate surface A semiconductor device comprising a ball bonding portion in which a ratio of an area of crystal grains having a [111] orientation to an area of 1.1 is 1.1 or more.   A semiconductor device for connecting an electrode portion on a semiconductor substrate and an external terminal by a bonding wire, and [111] orientation with respect to all crystal grains in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with the substrate surface And a ball bonding portion in which the area ratio of crystal grains having a [100] orientation is in the range of 30 to 95%.   A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and the ball surface in a horizontal direction is bonded to the substrate surface in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with the substrate surface. When the portion from the center of the cross section to 1/2 of the joining ball radius D is the core, the ratio of the area of the crystal grains having the [111] orientation to the area of the crystal grains having the [100] orientation in the core is A semiconductor device having a ball joint portion of 3 or less.   A semiconductor device in which an electrode portion on a semiconductor substrate and an external terminal are connected by a bonding wire, and the ball surface in a horizontal direction is bonded to the substrate surface in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with the substrate surface. The area of the crystal grain having the [111] orientation with respect to the area of the crystal grain having the [100] orientation in the outer peripheral portion when the outer portion from 2/3 of the joint ball radius D from the center of the cross section is the outer peripheral portion. A semiconductor device including a ball joint portion having a ratio of 0.9 or more.   A semiconductor device for connecting an electrode portion on a semiconductor substrate and an external terminal with a bonding wire, and [112] for all crystal grains in the crystal orientation in the vertical direction of the cross section in the cross section of the ball joint portion in the horizontal direction with the substrate surface, [113], [114], [115] A semiconductor device comprising a ball joint having a total area ratio of crystal grains having a [115] orientation of 3 to 40%.