JP6710141B2 - Copper alloy wire for ball bonding - Google Patents

Copper alloy wire for ball bonding Download PDF

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JP6710141B2
JP6710141B2 JP2016202254A JP2016202254A JP6710141B2 JP 6710141 B2 JP6710141 B2 JP 6710141B2 JP 2016202254 A JP2016202254 A JP 2016202254A JP 2016202254 A JP2016202254 A JP 2016202254A JP 6710141 B2 JP6710141 B2 JP 6710141B2
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wire
mass
ball
bonding
copper
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JP2018064050A (en
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満生 高田
満生 高田
裕之 天野
裕之 天野
菜那子 前田
菜那子 前田
祐佳 永江
祐佳 永江
拓也 濱本
拓也 濱本
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Tanaka Denshi Kogyo KK
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Tanaka Denshi Kogyo KK
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Priority to TW105141377A priority patent/TWI738695B/en
Priority to CN201710200765.3A priority patent/CN107958890A/en
Priority to KR1020170044133A priority patent/KR102176359B1/en
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Description

本発明は、ボールボンディング用銅合金線に関し、特にフリーエアボール（ＦＡＢ）ボンディングにより半導体素子上のパッド電極に第一ボンドをした後、ステッチボンディングにより、リードフレーム上の外部電極に第二ボンドをするボールボンディング用銅合金線の第一ボンドの改良に関するものである。 The present invention relates to a copper alloy wire for ball bonding, and in particular, after first bonding to a pad electrode on a semiconductor element by free air ball (FAB) bonding, second bonding to an external electrode on a lead frame by stitch bonding. The present invention relates to improvement of the first bond of a copper alloy wire for ball bonding.

これまで銅ニッケル等合金は、ボンディングワイヤとしてほとんど考慮されていなかった。ニッケル（Ｎｉ）、あるいは、白金（Ｐｔ）またはパラジウム（Ｐｄ）を添加すると銅（Ｃｕ）の抵抗が上昇する。このため、銅ニッケル等合金をボンディングワイヤにすると、金ボンディングワイヤの代替品として低抵抗を特徴とした銅ボンディングワイヤの優位性が失われてしまうという欠点がある。銅ニッケル等合金に関するボンディングワイヤを例示すると以下のものがある。 Until now, alloys such as copper-nickel have hardly been considered as bonding wires. When nickel (Ni) or platinum (Pt) or palladium (Pd) is added, the resistance of copper (Cu) increases. For this reason, when an alloy such as copper-nickel is used as the bonding wire, there is a drawback that the superiority of the copper bonding wire characterized by low resistance as a substitute for the gold bonding wire is lost. Examples of bonding wires for alloys such as copper-nickel are as follows.

特開平０１−２９１４３５号公報（後述する特許文献１）の特許請求の範囲（１）に「Ｓ、ＳｅおよびＴｅの総含有量を１．０ｐｐｍ以下とした高純度無酸素銅に、Ａｌ、Ｃｒ、Ｆｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓｎ、Ｚｎの１種または２種以上を総計で１．０〜５００ｐｐｍ添加したことを特徴とする半導体装置用銅合金極細線」からなる発明が開示され、第１表の実施例６に、高純度無酸素銅にＮｉ：３７６ｐｐｍを添加した素材からなる半導体装置用銅合金極細線が開示されている。 In Japanese Patent Application Laid-Open No. 01-291435 (Patent Document 1 described later), the scope of claim (1) states: "High-purity oxygen-free copper having a total content of S, Se and Te of 1.0 ppm or less, Al, Cr , Fe, Mn, Ni, P, Sn, Zn, or a total of 1.0 to 500 ppm of a total of 1.0 to 500 ppm of copper alloy extra fine wires for semiconductor devices is disclosed. Example 6 in Table 1 discloses a copper alloy extra fine wire for a semiconductor device, which is made of a material obtained by adding Ni: 376 ppm to high-purity oxygen-free copper.

また、特開平０１−２９０２３１号公報（後述する特許文献２）の特許請求の範囲（２）項には、「Ｓ、ＳｅおよびＴｅの総含有量を１．０ｐｐｍ以下とした高純度無酸素銅に、少なくともＳｉを１．０ｐｐｍ添加し、さらにＡｌ、Ｃｒ、Ｆｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓｎ、Ｚｎの１種または２種以上をＳｉと総計で１．０〜５００ｐｐｍ添加したことを特徴とする半導体装置用銅合金極細線」からなる発明が開示され、第２表の実施例９に、純度無酸素銅にＳｉ：５４ｐｐｍおよびＮｉ：４６ｐｐｍを添加したことを特徴とする半導体装置用銅合金極細線」が開示されている。 Further, in claim (2) of Japanese Patent Application Laid-Open No. 01-290231 (Patent Document 2 described later), "High-purity oxygen-free copper having a total content of S, Se, and Te of 1.0 ppm or less is described. In addition, at least 1.0 ppm of Si is further added, and one or more kinds of Al, Cr, Fe, Mn, Ni, P, Sn, and Zn are added to Si in a total amount of 1.0 to 500 ppm. A copper alloy for a semiconductor device, characterized in that Si: 54 ppm and Ni: 46 ppm are added to pure oxygen-free copper in Example 9 of Table 2 is disclosed. Extra fine wire" is disclosed.

しかしながら、同公報の第２表の比較例２では、高純度無酸素銅にＳｉ：８９ｐｐｍおよびＮｉ：６６０ｐｐｍを添加した素材は、ボール硬度が高くなり、被膜の損傷やマイクロクラックを回避できなかったことが記載されている。これは、ニッケル（Ｎｉ）の濃度が高くなると、表層における銅（Ｃｕ）マトリックス中で固溶したニッケル（Ｎｉ）が大気中の酸素と結びついて酸化ニッケル粒子を形成したためと考えられる。よって、この比較例２の素材を半導体装置用ボンディングワイヤに適用した場合、銅合金極細線として高温下で使用することができないことを示している。 However, in Comparative Example 2 in Table 2 of the publication, a material obtained by adding Si: 89 ppm and Ni: 660 ppm to high-purity oxygen-free copper has high ball hardness, and damage to the coating and microcracks cannot be avoided. Is described. It is considered that this is because when the concentration of nickel (Ni) increased, nickel (Ni) solid-solved in the copper (Cu) matrix in the surface layer was combined with oxygen in the atmosphere to form nickel oxide particles. Therefore, it is shown that when the material of Comparative Example 2 is applied to a bonding wire for a semiconductor device, it cannot be used as a copper alloy extra fine wire at a high temperature.

このような状況下で本出願人は、特開２０１４−１６５２７２号公報（ｄ３）に係る発明「断面減少率９９％以上で連続伸線され、表層と内部酸化層及び銅稀薄ニッケル合金層とから構成される半導体装置接合用銅ニッケル希薄合金ワイヤにおいて、上記表層は酸化物の成長層からなり、上記内部酸化層は金属不足型酸化銅マトリックスに酸化ニッケル粒子が微細に分散した層からなり、上記銅稀薄ニッケル合金層は純度９９．９９５質量％以上の銅（Ｃｕ）マトリックスに０．１〜１．５質量％のニッケル（Ｎｉ）が均一固溶した合金層であって、上記表面層の厚さに対する上記内部酸化層の厚さが６０倍以上である、ことを特徴とする半導体装置接合用銅稀薄ニッケル合金ワイヤの構造」を開示した。これは、銅（Ｃｕ）マトリックス中の酸素を固溶したニッケル（Ｎｉ）が固定することおよび銅稀薄ニッケル合金の表面層に純銅層が形成されやすくなることを利用しようとしたものである。 Under these circumstances, the applicant of the present invention discloses that the invention according to Japanese Patent Application Laid-Open No. 2014-165272 (d3) "continuously drawn with a cross-section reduction rate of 99% or more, and a surface layer, an internal oxide layer, and a copper dilute nickel alloy layer In the copper-nickel dilute alloy wire for bonding a semiconductor device, wherein the surface layer comprises an oxide growth layer, the internal oxide layer comprises a layer in which nickel oxide particles are finely dispersed in a metal-deficient copper oxide matrix, The copper dilute nickel alloy layer is an alloy layer in which 0.1 to 1.5 mass% of nickel (Ni) is uniformly solid-dissolved in a copper (Cu) matrix having a purity of 99.995 mass% or more, and the thickness of the surface layer is The thickness of the internal oxide layer is 60 times or more the thickness of the copper oxide nickel wire for semiconductor device bonding." This is intended to utilize the fact that nickel (Ni), which is a solid solution of oxygen in a copper (Cu) matrix, is fixed and that a pure copper layer is easily formed on the surface layer of a copper dilute nickel alloy.

その結果、このボンディングワイヤは、表層のＣｕ２Ｏ膜が周囲温度で成長するよりもはるかに速く、金属不足型銅酸化物（Ｃｕ２−ｘＯ）マトリックス中のフリーの酸素がＣｕ２−ｘＯマトリックス中をすばやく移動できる。よって、金属不足型銅酸化物（Ｃｕ２−ｘＯ）マトリックスがクッション層として働き、表層の半球状の酸化膜模様の形成が無くなり、表層のＣｕ２Ｏ膜が安定する。このため、このボンディングワイヤは、均一な再結晶組織が得られ、ワイヤが蛇行したり、リーニングしたりすることはない。すなわち、これまで溶融ボールが不規則に拡がるのは、リーニングと称されるボンディングワイヤの屈曲や折れ曲がりなどが解消された。また、第二ボンドにおけるボンディングワイヤのステッチ接合性も向上するなどの効果が得られる。 As a result, this bonding wire is much faster than the superficial Cu 2 O film growing at ambient temperature, with free oxygen in the metal-deficient copper oxide (Cu 2-x O) matrix being Cu 2-x. Can move quickly in O-matrix. Therefore, the metal-deficient cuprate (Cu 2-x O) matrix acts as a cushion layer, there is no formation of the surface layer of hemispherical oxide film pattern, the surface layer of the Cu 2 O film is stabilized. Therefore, this bonding wire has a uniform recrystallized structure, and the wire does not meander or lean. That is, the reason why the molten ball spreads irregularly up to now is that the bending and bending of the bonding wire, which is called leaning, is eliminated. In addition, the effect of improving the stitch bondability of the bonding wire in the second bond can be obtained.

しかしながら、例示した銅ニッケル希薄合金のボンディングワイヤには、いずれもワイヤ表面上に不安定な酸化膜が形成されやすいという致命的な欠陥がある。このためこれまでの銅ニッケル希薄合金ワイヤを長期間放置すると、ワイヤ表面の酸素濃度が増加してワイヤに不安定な酸化物が増殖される。このようなボンディングワイヤにフリーエアボール（ＦＡＢ）方式で溶融ボールを形成し、アルミパッドに鉛直方向から溶融ボールを押圧しても圧着ボールが円盤状に広がらず、圧着ボールの外延部がいびつな花びら状の形状で凝固する傾向があった。 However, each of the exemplified bonding wires of the copper-nickel dilute alloy has a fatal defect that an unstable oxide film is easily formed on the wire surface. Therefore, if the conventional copper-nickel dilute alloy wire is left for a long period of time, the oxygen concentration on the wire surface increases and unstable oxides grow on the wire. Even if a molten ball is formed on such a bonding wire by the free air ball (FAB) method and the molten ball is pressed against the aluminum pad from the vertical direction, the pressure-bonded ball does not spread in a disk shape, and the outer extension of the pressure-bonded ball is distorted. It tended to coagulate in a petal-like shape.

ここで、アルミパッドとは、純アルミニウム（Ａｌ）またはアルミニウム（Ａｌ）が主成分の合金からなるパッド電極のことである。また、花びら状という表現は、図５に示すように、圧着ボールの中心とワイヤの軸中心とが一致しているものの、圧着ボールの外延部の形状が円形でない状態をいう。すなわち、圧着ボールが花びら状になる現象は、溶融ボールが作製された段階では発生せずに、溶融ボールをアルミパッドに対して鉛直方向から押圧する段階で圧着ボールに現れる異常な形状である。花びら状の計測手段は後述する。 Here, the aluminum pad is a pad electrode made of pure aluminum (Al) or an alloy containing aluminum (Al) as a main component. As shown in FIG. 5, the expression “petal shape” means that the center of the crimp ball and the axial center of the wire are coincident with each other, but the shape of the extension of the crimp ball is not circular. That is, the phenomenon that the pressure-bonded ball becomes petal-like is an abnormal shape that does not occur in the stage where the melted ball is manufactured but appears in the pressure-bonded ball when the melted ball is pressed against the aluminum pad from the vertical direction. The petal-shaped measuring means will be described later.

この花びら状という現象は、これまでのリーニング等による凹部の花弁状欠陥（特開２００７−２８４７８７号公報の図１参照）、あるいは、歪んだ円形の圧着ボール（特開２００７−２６６３３９号公報の図２参照）のような状態をいうのではない。花弁状欠陥は、被覆層と芯材との界面構造に起因してボール接合部の最外周近傍が花弁状に凹凸変形を起こし、真円性からずれるものである。この花弁状欠陥は被覆層を有するボンディングワイヤにみられる現象であり、アルミパッド上の溶融ボールの濡れ性に起因する現象である。また、歪んだ円形の圧着ボールは、ワイヤ先端に形成したボール部がワイヤ軸に対し非対称に形成される現象であり、溶融ボールが形成された段階ですでに偏心している。さらに、リーニングは、ボンディングされたワイヤの第一ボンド付近において、鉛直方向から観察して再結晶領域（ＨＡＺ）と呼ばれる箇所で横方向に倒れるように曲がる現象である。このような偏心ボールが形成されたボンディングワイヤをアルミパッドに対して鉛直方向から押圧すると、後述するように、歪んだ円形の圧着ボールを一般的な顕微鏡下で観察することができる。これらの偏心ボールの一例を図７に示す。 This petal-like phenomenon is caused by a petal-like defect of a recess due to the conventional leaning (see FIG. 1 of JP 2007-284787 A) or a distorted circular pressure bonding ball (see the drawing of JP 2007-266339 A). It does not mean a state like (see 2). The petal-like defect is caused by the interface structure between the coating layer and the core material, causing a petal-like uneven deformation in the vicinity of the outermost periphery of the ball bonding portion, which deviates from the perfect circularity. This petal-like defect is a phenomenon found in a bonding wire having a coating layer, and is a phenomenon caused by the wettability of a molten ball on an aluminum pad. The distorted circular pressure-bonded ball is a phenomenon in which the ball portion formed at the tip of the wire is formed asymmetrically with respect to the wire axis, and is already eccentric when the molten ball is formed. Further, leaning is a phenomenon in which the wire is bent so as to fall laterally at a portion called a recrystallization region (HAZ) when observed from the vertical direction in the vicinity of the first bond of the bonded wire. When the bonding wire on which such an eccentric ball is formed is pressed against the aluminum pad from the vertical direction, a distorted circular pressure-bonded ball can be observed under a general microscope, as described later. An example of these eccentric balls is shown in FIG.

偏心ボールでも歪んだ圧着ボールが発生すると、それを考慮してアルミパッドの圧着面積が大きくならざるを得ない。このため、これまではアルミパッドの単位面積当たりのボンディングワイヤの密集度を高くできないという欠点があった。また、偏心により圧着ボールがアルミパッドからはみ出すかどうかにかかわらず、近年の実装工程ではボンディングワイヤの集積密度がますます高まってきた。そのためボンディングワイヤの密集度を高めようとすると、第一ボンド工程において圧着ボールが、図５に示すように花びら状に変形するという現象そのものが許容されなくなってきた。 If a distorted crimp ball is generated even with an eccentric ball, the crimp area of the aluminum pad must be increased in consideration of it. Therefore, there has been a drawback that the density of bonding wires per unit area of the aluminum pad cannot be increased so far. In addition, the integration density of bonding wires has increased more and more in the recent mounting process regardless of whether or not the crimped balls protrude from the aluminum pad due to the eccentricity. Therefore, when it is attempted to increase the density of the bonding wires, the phenomenon that the pressure-bonded balls are deformed into a petal shape as shown in FIG. 5 in the first bonding step has become unacceptable.

この花びら状という現象は、無垢のボンディングワイヤにあってこれまでまったく考慮されてこなかった課題である。「花びら状」という現象は銅合金の結晶構造に起因する。すなわち、花びら状現象は、溶融ボールが凝固する際、凝固組織の不均一さに起因して圧着ボールが等方的に凝固しない問題である。そのため、「花びら状」現象には、後述する実施例および比較例に示すように様々なものがあり、溶融ボールがキャピラリによって圧着され、凝固する際にこの「花びら状」現象がみられる。この原因は定かではないが、凝固組織の不均一さが関与しており、その結果、アルミパッドと圧着ボールの界面状態が不均質になるのである。「花びら状」現象がみられると、実装工程が安定しないので、実装工程で許容されなくなる。 This petal-like phenomenon is a problem that has never been taken into consideration in solid bonding wires. The phenomenon of "petal shape" is caused by the crystal structure of the copper alloy. That is, the petal-like phenomenon is a problem that when the molten ball is solidified, the pressure-bonded ball is not isotropically solidified due to the nonuniformity of the solidified structure. Therefore, there are various "petal-like" phenomena as shown in Examples and Comparative Examples described later, and this "petal-like" phenomenon is observed when the molten ball is pressed by the capillary and solidifies. The cause of this is not clear, but the nonuniformity of the solidification structure is involved, and as a result, the interfacial state between the aluminum pad and the pressure bonding ball becomes nonuniform. If the "petal-like" phenomenon is observed, the mounting process is not stable, so that it is not allowed in the mounting process.

他方、本発明の銅合金線のボンディングワイヤを製造するにはこれまでのいくつかの製造方法を適宜利用することができる。
たとえば、特開昭５９−１５５１６１号公報の実施例には、「まず無酸素銅を用いて直径０．１３ｍｍの素材ワイヤを製造する。…（中略）…このようにして得られた金メッキワイヤを、引抜加工によって直径０．０２５ｍｍに仕上げる。必要に応じて約３５０度Ｃで焼鈍を行う」ことが示されている。 On the other hand, in order to manufacture the bonding wire of the copper alloy wire of the present invention, the several manufacturing methods up to now can be appropriately utilized.
For example, in the example of Japanese Patent Laid-Open No. 59-155161, "First, a raw material wire having a diameter of 0.13 mm is manufactured using oxygen-free copper.... (Omitted)... The gold-plated wire thus obtained is used. The diameter is 0.025 mm by drawing. If necessary, annealing is performed at about 350° C.”.

同様に、特開平０３−１３５０４１号公報の特許請求の範囲第１項には、「導体の表面に、合金元素あるいは高濃度合金を蒸着、メッキにより被覆した後、拡散熱処理を施すことにより合金化を行ない、その後伸線することを特徴とする半導体用ボンディング細線の製造方法」の発明が示されている。 Similarly, in claim 1 of Japanese Patent Laid-Open No. 03-135041, "The surface of the conductor is alloyed by depositing an alloying element or a high-concentration alloy by vapor deposition and plating, and then performing a diffusion heat treatment. The method of manufacturing a bonding thin wire for a semiconductor characterized in that the wire is drawn and then drawn.

また、特開昭６４−００３９０３号公報の特許請求の範囲第（３）項には、所定のＣｕ合金の鋳塊に、「熱間圧延を施し、その後伸線加工と少なくとも１回以上中間焼鈍を繰返して所定の線径に仕上げ、しかる後非酸化性又は還元性雰囲気下で焼鈍することにより、所望の機械的特性とすることを特徴とする電子機器用銅細線の製造法」の発明が示されている。 Further, in claim (3) of Japanese Patent Laid-Open No. 64-003903, the ingot of a predetermined Cu alloy is described as follows: "Hot rolling is performed, and then wire drawing and at least one intermediate annealing. The invention of “a method for producing a copper fine wire for electronic equipment, characterized in that desired mechanical properties are obtained by repeating the above to finish a predetermined wire diameter and then annealing in a non-oxidizing or reducing atmosphere” It is shown.

同様に、特開平１１−２９３４３１号公報の請求項１には、「晶出物などの異相を含む銅合金軟質素材を冷間加工し、必要に応じて中間焼鈍を施す、線径５０μｍ以下の銅合金極細線の製造方法であって、前記銅合金軟質素材からの冷間加工率を９９．９９９％以下とし、中間焼鈍を施す場合は、中間焼鈍と中間焼鈍の間の冷間加工率は９９．９９９％以下とし、最終中間焼鈍後の冷間加工率は８０〜９９％にすることを特徴とする銅合金銅細線の製造方法」の発明が示されている。 Similarly, in claim 1 of Japanese Patent Application Laid-Open No. 11-293431, "a copper alloy soft material containing a heterogeneous phase such as a crystallized product is cold-worked, and if necessary, an intermediate annealing is performed. In the method for producing a copper alloy ultrafine wire, the cold working rate from the copper alloy soft material is 99.999% or less, and when performing intermediate annealing, the cold working rate between the intermediate annealing is 99.999% or less, and the cold working rate after the final intermediate annealing is 80 to 99%".

特開平０１−２９１４３５号公報Japanese Patent Laid-Open No. 01-291435 特開平０１−２９０２３１号公報Japanese Patent Laid-Open No. 01-290231 特開２０１４−１６５２７２号公報JP, 2014-165272, A

本発明者等は、銅合金線ボンディングワイヤの花びら状現象を注意深く観察し、このような花びら状に拡がる現象は、製造直後のボンディングワイヤで観察されず、数か月放置したボンディングワイヤでみられたことに気が付いた。他方、無垢の純銅線の場合には、製造直後でも同様にボンディングワイヤの圧着ボールが花びら状に拡がることがあった。そこで、本発明者等は、圧着ボールが花びら状に拡がらない合金組成を種々探索し、さらに研究を進めて本発明を完成させるに至った。 The present inventors have carefully observed the petal-like phenomenon of the copper alloy wire bonding wire, and such a petal-like spread phenomenon is not observed in the bonding wire immediately after production, and is observed in the bonding wire left for several months. I realized that. On the other hand, in the case of pure pure copper wire, the bonding ball of the bonding wire may spread like a petal immediately after the production. Therefore, the inventors of the present invention have searched various alloy compositions in which the pressure-bonded balls do not spread like petals, and have further researched to complete the present invention.

本発明の目的は、ボンディングワイヤを細くして溶融ボールを小さくしても、圧着ボールが花びら状に拡がらず、安定して均一な圧着形状を確保することができるボールボンディング用銅合金線を提供することにある。 An object of the present invention is to provide a copper alloy wire for ball bonding, which can secure a stable and uniform crimped shape without spreading the crimped ball in a petal-like shape even if the bonding wire is thinned to make the molten ball small. To provide.

本発明のボールボンディング用銅合金線の一つは、ボールボンディング用銅希薄合金において、０．１〜１．５質量％のニッケル（Ｎｉ）、０．０１〜１．５質量％の白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に０．１〜２０質量ｐｐｍのイオウ（Ｓ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とする。 One of the copper alloy wires for ball bonding of the present invention is a diluted copper alloy for ball bonding, which is 0.1 to 1.5 mass% nickel (Ni) and 0.01 to 1.5 mass% platinum (Pt). ) Or palladium (Pd) in a total amount of 0.01 to 1.5 mass%, further 0.1 to 20 mass ppm of sulfur (S), and 10 to 80 mass ppm of oxygen (O). ) And the balance copper (Cu).

また、本発明のボールボンディング用銅合金線の他の一つは、０．１〜１．５質量％のニッケル（Ｎｉ）、０．０１〜１．５質量％の白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に１０〜１００質量ｐｐｍのリン（Ｐ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とする。 Another one of the copper alloy wires for ball bonding of the present invention is 0.1 to 1.5% by mass of nickel (Ni), 0.01 to 1.5% by mass of platinum (Pt) or palladium ( 0.01 to 1.5 mass% in total of one or more of Pd), further 10 to 100 mass ppm phosphorus (P), 10 to 80 mass ppm oxygen (O), and the balance copper (Cu). ) Consists of.

また、本発明のボールボンディング用銅合金線の他の一つは、０．１〜１．５質量％のニッケル（Ｎｉ）、０．０１〜１．５質量％の白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に０．１〜２０質量ｐｐｍのイオウ（Ｓ）、１０〜１００質量ｐｐｍのリン（Ｐ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とする。 Another one of the copper alloy wires for ball bonding of the present invention is 0.1 to 1.5% by mass of nickel (Ni), 0.01 to 1.5% by mass of platinum (Pt) or palladium ( 0.01 to 1.5 mass%, 0.1 to 20 mass ppm of sulfur (S), 10 to 100 mass ppm of phosphorus (P), and 10 to 100 mass ppm of Pd). It is characterized by comprising 80 mass ppm of oxygen (O) and the balance copper (Cu).

本発明の実施態様は以下のとおりである。すなわち、上記ニッケル（Ｎｉ）の含有量が０．２〜１．２質量％であることが好ましい。より好ましくは、０．５〜１．０質量％の範囲である。また、上記白金（Ｐｔ）またはパラジウム（Ｐｄ）の含有量が０．０５〜０．８質量％であることが好ましい。そして、白金（Ｐｔ）またはパラジウム（Ｐｄ）よりもニッケル（Ｎｉ）からなる銅希薄合金が好ましい。特にニッケル（Ｎｉ）および白金（Ｐｔ）またはパラジウム（Ｐｄ）からなる銅希薄合金がより好ましい。また、上記イオウ（Ｓ）の含有量が２〜１０質量ｐｐｍであることが好ましい。 Embodiments of the present invention are as follows. That is, the content of nickel (Ni) is preferably 0.2 to 1.2 mass %. More preferably, it is in the range of 0.5 to 1.0 mass %. The content of platinum (Pt) or palladium (Pd) is preferably 0.05 to 0.8 mass%. And, a copper dilute alloy made of nickel (Ni) is preferable to platinum (Pt) or palladium (Pd). In particular, a copper dilute alloy made of nickel (Ni) and platinum (Pt) or palladium (Pd) is more preferable. Further, the content of the sulfur (S) is preferably 2 to 10 mass ppm.

本発明において、銅マトリックスに０．１〜１．５質量％のニッケル（Ｎｉ）、０．０１〜１．５質量％の白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％含有させるのは、これらの含有合金成分が銅マトリックスに完全に均一固溶するからである。また、ニッケル（Ｎｉ）等の含有合金成分は銅マトリックス中に存在する酸素を固定する作用を示すからである。また、この範囲内であれば、銅合金線ワイヤの表面に銅（Ｃｕ）の含有量が高い表面偏析層が生じることはない。 In the present invention, one or more of 0.1 to 1.5% by mass of nickel (Ni), 0.01 to 1.5% by mass of platinum (Pt) or palladium (Pd) is added to the copper matrix. The total content of 0.01 to 1.5 mass% is included because these contained alloy components are completely homogeneously solid-dissolved in the copper matrix. Also, the contained alloy component such as nickel (Ni) has a function of fixing oxygen existing in the copper matrix. Within this range, a surface segregation layer having a high copper (Cu) content does not occur on the surface of the copper alloy wire.

ニッケル（Ｎｉ）の含有量の下限値を０．１質量％とし、白金（Ｐｔ）またはパラジウム（Ｐｄ）の下限値を０．０１質量％としたのは、この下限値未満では結晶粒が粗大化し圧着時に局所的に変形してしまうからである。他方、ニッケル（Ｎｉ）等のうちのいずれか１種以上の上限値を合計で１．５質量％としたのは、この上限値を超えると、圧着ボールが硬くなりすぎてチップダメージを起こすからである。ニッケル（Ｎｉ）の含有量が０．２〜１．２質量％であり、白金（Ｐｔ）またはパラジウム（Ｐｄ）の含有量が０．０５〜０．８質量％であれば、圧着ボールの結晶粒径がある程度均一な大きさになり、安定した円盤状の圧着ボールが得られる。銅合金の圧着ボール形状に関しては白金（Ｐｔ）またはパラジウム（Ｐｄ）よりもニッケル（Ｎｉ）のほうが、作用効果が大きい。ニッケル（Ｎｉ）の含有量が０．５〜１．０質量％の範囲が特に好ましい。 The lower limit of the content of nickel (Ni) was set to 0.1% by mass, and the lower limit of platinum (Pt) or palladium (Pd) was set to 0.01% by mass. This is because they are locally deformed during compression. On the other hand, the upper limit of at least one of nickel (Ni) and the like is set to 1.5% by mass in total, because if the upper limit is exceeded, the pressure-bonded balls become too hard and chip damage occurs. Is. If the content of nickel (Ni) is 0.2 to 1.2% by mass and the content of platinum (Pt) or palladium (Pd) is 0.05 to 0.8% by mass, the pressure-bonded ball crystal is formed. The particle size becomes uniform to some extent, and a stable disc-shaped pressure-bonded ball can be obtained. Regarding the pressure bonding ball shape of the copper alloy, nickel (Ni) has a larger effect than platinum (Pt) or palladium (Pd). It is particularly preferable that the content of nickel (Ni) is 0.5 to 1.0% by mass.

本発明の銅合金線ワイヤに０．１〜２０質量ｐｐｍのイオウ（Ｓ）を含有させると、意外にも酸素の侵入を止める効果のあることが分かった。これまでイオウ（Ｓ）は溶融した銅ボールを硬くするので、添加元素から排除されていた元素である。０．１〜２０質量ｐｐｍのイオウ（Ｓ）は銅合金線ワイヤの表面層を支配して表面希薄層をつくることもない。 It was found that, when the copper alloy wire of the present invention contains 0.1 to 20 mass ppm of sulfur (S), it has an unexpected effect of stopping the invasion of oxygen. Sulfur (S) is an element that has been excluded from the additive elements so far because it hardens the molten copper balls. 0.1 to 20 mass ppm of sulfur (S) dominates the surface layer of the copper alloy wire and does not form a surface dilute layer.

イオウ（Ｓ）が０．１質量ｐｐｍ以上あると銅合金線の表面層を支配し、酸素の侵入を止めることができる。他方、イオウ（Ｓ）が２０質量ｐｐｍを超えると、圧着ボールが硬くなりすぎ、ボールボンディングするとアルミスプラッシュを起こす。よって、イオウ（Ｓ）の含有量を０．１〜２０質量ｐｐｍとした。イオウ（Ｓ）は銅合金線ワイヤに及ぼす影響力が強いので、イオウ（Ｓ）の含有量は２〜１０質量ｐｐｍであることが好ましい。 When the amount of sulfur (S) is 0.1 mass ppm or more, it can control the surface layer of the copper alloy wire and stop the invasion of oxygen. On the other hand, if the sulfur (S) exceeds 20 mass ppm, the pressure-bonded balls become too hard, and ball bonding causes aluminum splash. Therefore, the content of sulfur (S) is set to 0.1 to 20 mass ppm. Since sulfur (S) has a strong influence on the copper alloy wire, the content of sulfur (S) is preferably 2 to 10 mass ppm.

本発明の銅合金線ワイヤが大気中で長期保存に耐えるには、ワイヤ中にある程度の酸素量が必要である。本発明の銅合金線ワイヤに１０〜８０質量ｐｐｍの酸素（Ｏ）を含有させておくと、圧着ボール形状が安定する効果のあることが分かった。ニッケル酸化物等が銅マトリックス中に固定され、この酸化物粒子のピン止め効果によって圧着ボールの結晶粒径がある程度の均一な大きさに保たれるからである。酸素（Ｏ）が下限値未満であればこのような抑制効果はなくなる。また、酸素（Ｏ）が上限値を超えると、第２接合点（ボンディングワイヤとリードフレームや基板などとの接合点）において接合性が低下するため、接合不良や実装工程での歩留まり低下が発生する。よって、ボンディングワイヤとして使用する際の酸素（Ｏ）の含有量を１０〜８０質量ｐｐｍとした。 The copper alloy wire of the present invention requires a certain amount of oxygen in the wire to withstand long-term storage in the air. It was found that when the copper alloy wire of the present invention contains oxygen (O) in an amount of 10 to 80 mass ppm, the shape of the pressure-bonded ball is stabilized. This is because nickel oxide or the like is fixed in the copper matrix and the pinning effect of the oxide particles maintains the crystal grain size of the pressure-bonded balls to a certain uniform size. If oxygen (O) is less than the lower limit value, such a suppressing effect disappears. Further, when oxygen (O) exceeds the upper limit value, the bondability at the second bonding point (the bonding point between the bonding wire and the lead frame, the substrate, etc.) deteriorates, resulting in defective bonding and a reduction in the yield in the mounting process. To do. Therefore, the content of oxygen (O) when used as a bonding wire is set to 10 to 80 mass ppm.

特にニッケル（Ｎｉ）は酸素（Ｏ）と酸化物を形成して銅（Ｃｕ）マトリックス中に固定されるので、ピン止め効果が大きくなる。ただし、酸素（Ｏ）は銅マトリックスを透過するので、通常の銅合金線においては、ニッケル（Ｎｉ）などが酸化ニッケル等になる分だけ酸素を含有することができる。しかしながら、酸化ニッケル等の酸化物になると、この体積膨張が呼び水となって大気中から銅マトリックスへ酸素が侵入しやすくなる。そこで、所定量のイオウ（Ｓ）またはリン（Ｐ）を添加することによって酸素（Ｏ）の侵入を抑制することにした。すなわち、所定量のイオウ（Ｓ）またはリン（Ｐ）を添加することによって数か月放置しても本発明の銅合金線ワイヤに含まれる酸素（Ｏ）の含有量があまり増加しない効果がある。 Particularly, since nickel (Ni) forms an oxide with oxygen (O) and is fixed in the copper (Cu) matrix, the pinning effect is increased. However, since oxygen (O) permeates the copper matrix, a normal copper alloy wire can contain oxygen as much as nickel (Ni) or the like becomes nickel oxide or the like. However, in the case of an oxide such as nickel oxide, this volume expansion serves as priming water, and oxygen easily enters the copper matrix from the atmosphere. Therefore, it has been decided to suppress the intrusion of oxygen (O) by adding a predetermined amount of sulfur (S) or phosphorus (P). That is, by adding a predetermined amount of sulfur (S) or phosphorus (P), there is an effect that the content of oxygen (O) contained in the copper alloy wire of the present invention does not increase so much even if it is left for several months. ..

本発明において１０〜１００質量ｐｐｍのリン（Ｐ）は、銅合金線ワイヤを酸化させない効果のほかに、溶融ボールを形成したときにフラックス作用を示してワイヤ表面の酸化膜を除去する効果がある。リン（Ｐ）が下限値の１０質量ｐｐｍ未満では上記効果がない。また、リン（Ｐ）が上限値の１００質量ｐｐｍを超えると、アルミパッド上でアルミスプラッシュを起こす。よって、リン（Ｐ）の範囲を１０〜１００質量ｐｐｍとした。 In the present invention, 10 to 100 ppm by mass of phosphorus (P) has an effect of not only oxidizing the copper alloy wire wire but also showing a flux action when forming the molten ball to remove an oxide film on the wire surface. .. If phosphorus (P) is less than the lower limit of 10 mass ppm, the above effect is not obtained. When phosphorus (P) exceeds the upper limit value of 100 mass ppm, aluminum splash occurs on the aluminum pad. Therefore, the range of phosphorus (P) is set to 10 to 100 mass ppm.

本発明の銅合金線細線において、素材となる高純度銅（Ｃｕ）の純度は９９．９９質量％以上あればよい。リン脱酸銅や無酸素銅を用いることができる。残りの０．０１質量％未満には、銀（Ａｇ）や鉄（Ｆｅ）が代表的に含まれる。その他、鉛（Ｐｂ）、スズ（Ｓｎ）、アンチモン（Ｓｂ）、ヒ素（Ａｓ）、ビスマス（Ｂｉ）、クロム（Ｃｒ）、テルル（Ｔｅ）、セレン（Ｓｅ）、シリコン（Ｓｉ）などが含まれる。 In the copper alloy thin wire of the present invention, the purity of the high-purity copper (Cu) used as a material may be 99.99% by mass or more. Phosphorus deoxidized copper and oxygen-free copper can be used. The remaining less than 0.01 mass% typically contains silver (Ag) and iron (Fe). In addition, lead (Pb), tin (Sn), antimony (Sb), arsenic (As), bismuth (Bi), chromium (Cr), tellurium (Te), selenium (Se), silicon (Si) and the like are included. ..

素材となる高純度銅（Ｃｕ）の純度は高いほど不純物が少なくなるので好ましい。高純度銅（Ｃｕ）の純度は、９９．９９５質量％以上、より好ましくは９９．９９８質量％以上、最も好ましくは９９．９９９８質量％以上である。しかし、本発明の銅合金線においては、ニッケル（Ｎｉ）、白金（Ｐｔ）またはパラジウム（Ｐｄ）の含有量が％オーダーなので、これらのｐｐｍオーダーの不純物の影響は無視することができる。 The higher the purity of the high-purity copper (Cu) used as a raw material, the less impurities are contained, which is preferable. The purity of high-purity copper (Cu) is 99.995% by mass or more, more preferably 99.998% by mass or more, and most preferably 99.9998% by mass or more. However, in the copper alloy wire of the present invention, the content of nickel (Ni), platinum (Pt), or palladium (Pd) is on the order of %, so the influence of these ppm-order impurities can be ignored.

本発明の銅合金線は、所定量のイオウ（Ｓ）、あるいは、リン（Ｐ）の存在によって大気中の酸素による酸化の影響を少なくすることができる。よって、不活性雰囲気中であれば最終線径前の線径５０〜２５０μｍで熱処理を施しても、極端に酸素量が増えることがないことがわかった。このような熱処理を施す場合は、非酸化性雰囲気で温度は４００℃〜７００℃で行い、熱処理した線径にて常温での伸び率が５〜２５％となる条件であれば、本発明の酸素量を所定の範囲にとどめることができる。 The copper alloy wire of the present invention can reduce the influence of oxidation by oxygen in the atmosphere due to the presence of a predetermined amount of sulfur (S) or phosphorus (P). Therefore, it was found that the oxygen amount does not extremely increase even if the heat treatment is performed with a wire diameter of 50 to 250 μm before the final wire diameter in an inert atmosphere. When such a heat treatment is performed, the temperature is 400° C. to 700° C. in a non-oxidizing atmosphere, and the elongation of the heat treated wire diameter at room temperature is 5 to 25% under the conditions of the present invention. The amount of oxygen can be kept within a predetermined range.

また、本発明のボールボンディング用銅合金線においては、貴金属めっきされたアルミニウムパッドを用いることができる。ボンディングワイヤからアルミニウムパッド中に酸素が侵入するのを防ぐためである。貴金属めっきは、金（Ａｕ）めっき、銀（Ａｇ）めっき、パラジウム（Ｐｄ）めっきの軟質めっきがよい。また、めっき硬さはボールボンディング用銅合金線の静的硬さと同程度にしておくと、溶融ボールの組成流動をコントロールすることができ、チップ割れを防ぐことができる。具体的にはめっき硬さをヌープ硬さで測定し、ボンディングワイヤのビッカース硬さに近似させることができる。 Further, in the copper alloy wire for ball bonding of the present invention, an aluminum pad plated with a noble metal can be used. This is to prevent oxygen from penetrating into the aluminum pad from the bonding wire. The noble metal plating is preferably soft plating such as gold (Au) plating, silver (Ag) plating, and palladium (Pd) plating. Further, if the plating hardness is set to be approximately the same as the static hardness of the copper alloy wire for ball bonding, the composition flow of the molten ball can be controlled and chip cracking can be prevented. Specifically, the plating hardness can be measured by Knoop hardness to approximate the Vickers hardness of the bonding wire.

また、本発明においては、リードフレームが銅（Ｃｕ）合金または鉄（Ｆｅ）素材に銅（Ｃｕ）または銅（Ｃｕ）合金が電気めっき等により被覆されたものであるものを用いることもできる。リードフレーム以外にも、ＢＧＡ（Ｂａｌｌ Ｇｒｉｄ Ａｒｒａｙ）のような樹脂基板や、ＱＦＮ（Ｑｕａｄ Ｆｌａｔ Ｎｏｎ−ｌｅａｄｅｄ ｐａｃｋａｇｅ）のようなリードのないフレームなど、ボンディングワイヤが一般的な電気接合線用途として使用される様々なパッケージにも適用されることが可能である。 In the present invention, the lead frame may be a copper (Cu) alloy or iron (Fe) material coated with copper (Cu) or a copper (Cu) alloy by electroplating or the like. In addition to lead frames, bonding wires such as resin substrates such as BGA (Ball Grid Array) and leadless frames such as QFN (Quad Flat Non-leaded package) are generally used for electrical connection lines. It can also be applied to various packages.

本発明のボールボンディング用銅合金線においては、１週間程度放置しても銅合金線中に含まれる酸素の含有量はほとんど変化しない。しかも、アルミパッドに対して鉛直方向から溶融ボールを押圧してできた圧着ボールの溶着面積が広がらず、花びら状に拡がる現象は生じない。よって、第一ボンディングにおいて安定して均一な溶着面積を確保することができ、高密度実装用ボンディングワイヤとして最適となる。特に直径を１８μｍ以下にしても、溶融ボールが硬くならず、溶着面積がほとんど変化しない。また、生産性、あるいは、セカンド接合性やルーピング特性など他のボンディング特性は、従前のボンディングワイヤと同様に優れている。 In the copper alloy wire for ball bonding of the present invention, the content of oxygen contained in the copper alloy wire hardly changes even if it is left for about one week. Moreover, the welded area of the pressure bonding ball formed by pressing the molten ball against the aluminum pad in the vertical direction does not increase, and the phenomenon of petal-shaped expansion does not occur. Therefore, a stable and uniform welded area can be secured in the first bonding, which is optimal as a bonding wire for high-density mounting. In particular, even if the diameter is 18 μm or less, the molten ball does not become hard and the welded area hardly changes. Further, the productivity or other bonding characteristics such as the second bonding property and the looping property are excellent as in the conventional bonding wire.

は、実施例１の溶融ボールの圧着状態を示す顕微鏡写真である。3 is a micrograph showing a pressure-bonded state of the molten ball of Example 1. FIG. は、実施例２の溶融ボールの圧着状態を示す顕微鏡写真である。4A is a micrograph showing a pressed state of the molten ball of Example 2. FIG. は、実施例３の溶融ボールの圧着状態を示す顕微鏡写真である。4A is a micrograph showing a pressure-bonded state of a molten ball of Example 3. FIG. は、実施例４の溶融ボールの圧着状態を示す顕微鏡写真である。4A is a micrograph showing a pressed state of a molten ball of Example 4. FIG. は、比較例１の溶融ボールの圧着状態を示す顕微鏡写真である。[Fig. 4] is a micrograph showing a pressure-bonded state of a molten ball of Comparative Example 1. は、花びら状の形状の計測手段を示す顕微鏡写真である。[Fig. 4] is a micrograph showing a petal-shaped measuring means. は、従来の偏心ボールの圧着状態を示す顕微鏡写真である。[Fig. 4] is a micrograph showing a pressure-bonded state of a conventional eccentric ball.

［実施例１］
市販の純度９９．９９９９質量％以上の電解銅素材に、純度９９．９９９質量％以上のニッケル（Ｎｉ）を０．２５質量％、純度９９．９９９質量％以上の白金（Ｐｔ）を０．５質量％、イオウ（Ｓ）を１０質量ｐｐｍ、およびリン（Ｐ）を１５質量ｐｐｍ、それぞれ配合して所定の銅合金線を得た。この合金を連続鋳造後、ダイヤモンドダイスを使用して、連続伸線加工し、直径１８μｍのワイヤを得た。その後、常温での伸び率が１０％となるように、最終連続焼鈍を約５００℃にて行った。このワイヤを室温の大気中に３日間放置した後、この合金ワイヤの酸素濃度を測定したところ、２５質量ｐｐｍであった。このボンディングワイヤを実施例１とした。 [Example 1]
To a commercially available electrolytic copper material having a purity of 99.9999% by mass or more, 0.25% by mass of nickel (Ni) having a purity of 99.999% by mass or more, and 0.5% of platinum (Pt) having a purity of 99.999% by mass or more. % By mass, sulfur (S) by 10 mass ppm, and phosphorus (P) by 15 mass ppm were each mixed to obtain a predetermined copper alloy wire. After continuous casting of this alloy, continuous drawing was performed using a diamond die to obtain a wire having a diameter of 18 μm. Then, final continuous annealing was performed at about 500° C. so that the elongation at room temperature was 10%. After this wire was left in the air at room temperature for 3 days, the oxygen concentration of this alloy wire was measured and found to be 25 mass ppm. This bonding wire is referred to as Example 1.

（第一ボンドの接合性試験）
この実施例１のボンディングワイヤをボンディングマシン（装置名：キューリックアンドソファー社製ＩＣｏｎｎタイプ）を用いて０．８μｍ厚のＡｌ−０．５質量％Ｃｕパッド上へボールボンディングを１００本連続して行った。このパッドは厚さ０．２０ｍｍのチップ上にある。フリーエアーボール（ＦＡＢ）の作製条件は、ＦＡＢ径が線径の１．５倍となるように設定し、第一ボンドの超音波および荷重の条件は圧着径がＦＡＢの１．３倍となるよう設定した。ループ長さは２．５ｍｍ、ループ高さは３００μｍとした。 (First bond bondability test)
Using the bonding machine of Example 1, a ball bonding machine (device name: IConn type manufactured by Curic & Sofa Co., Ltd.) was used to continuously perform 100 ball bondings on a 0.8 μm thick Al-0.5 mass% Cu pad. went. This pad is on a 0.20 mm thick chip. The free air ball (FAB) manufacturing conditions are set so that the FAB diameter is 1.5 times the wire diameter, and the ultrasonic and load conditions for the first bond are that the crimping diameter is 1.3 times the FAB. Was set. The loop length was 2.5 mm and the loop height was 300 μm.

第一ボンドの全数の溶着状態を一般的な測定顕微鏡（オリンパス社製のＳＴＭ６）の対物レンズ５０倍で観察して目視で優と判断した。このボンディングワイヤの圧着ボールの代表的な５個の外観（「実施例１型」と称す）を図１に示す。５個の圧着ボール径の平均値は２７μｍ、圧着ボール厚みは１１μｍであった。 The welded state of all the first bonds was observed with a general measuring microscope (STM6 manufactured by Olympus Co., Ltd.) with an objective lens of 50 times and visually judged to be excellent. FIG. 1 shows the appearance of five representative bonding balls of this bonding wire (referred to as “Example 1 type”). The average value of the diameters of the five pressure bonding balls was 27 μm, and the thickness of the pressure bonding balls was 11 μm.

［実施例２］
市販の純度９９．９９質量％以上の無酸素銅素材に、純度９９．９９質量％以上のニッケル（Ｎｉ）を０．５質量％、純度９９．９９質量％以上のパラジウム（Ｐｄ）を０．２５質量％、イオウ（Ｓ）を１５質量ｐｐｍ、およびリン（Ｐ）を８０質量ｐｐｍ、それぞれ配合して所定の銅合金線を得た。この合金を連続鋳造後、ダイヤモンドダイスを使用して、連続伸線加工した。なお、連続伸線加工途中の直径６０μｍで５００℃の熱処理し、その線径で常温の伸び率を測定すると１５％であった。その後に再度連続伸線加工を行い最終線径１８μｍのワイヤまで加工し、常温での伸び率が１２％となるように、最終連続焼鈍を約５５０℃にて行った。このワイヤを室温の大気中に３日間放置した後、この合金ワイヤの酸素濃度を測定したところ、３１質量ｐｐｍであった。このボンディングワイヤを実施例２とした。 [Example 2]
A commercially available oxygen-free copper material having a purity of 99.99 mass% or more, 0.5 mass% of nickel (Ni) having a purity of 99.99 mass% or more, and palladium (Pd) having a purity of 99.99 mass% or more of 0. 25 mass%, sulfur (S) 15 mass ppm, and phosphorus (P) 80 mass ppm were each mixed, and the predetermined copper alloy wire was obtained. After continuous casting of this alloy, continuous drawing was performed using a diamond die. In addition, when heat treatment was performed at 500° C. with a diameter of 60 μm during the continuous wire drawing, and the elongation at room temperature was measured with the wire diameter, it was 15%. After that, continuous wire drawing was performed again to wire up to a final wire diameter of 18 μm, and final continuous annealing was performed at about 550° C. so that the elongation at room temperature was 12%. After the wire was left in the atmosphere at room temperature for 3 days, the oxygen concentration of the alloy wire was measured and found to be 31 mass ppm. This bonding wire is referred to as Example 2.

（第一ボンドの接合性試験）
この実施例２のボンディングワイヤを実施例１と同様にして１００本ボンディングを行った。第一ボンドの全数の溶着状態を一般的な測定顕微鏡（オリンパス社製ＳＴＭ６）の対物レンズ５０倍で観察して目視で良と判断した。このボンディングワイヤの圧着ボールの代表的な５個の外観（「実施例２型」と称す）を図２に示す。圧着ボール径の平均値は２７μｍ、圧着ボール厚みは１１μｍであった。 (First bond bondability test)
100 pieces of the bonding wires of this Example 2 were bonded in the same manner as in Example 1. The welded state of all of the first bonds was observed with a general measuring microscope (STM6 manufactured by Olympus Co., Ltd.) with a 50× objective lens and visually judged to be good. FIG. 2 shows the appearance of five representative pressure-bonded balls of this bonding wire (referred to as “Example 2 type”). The average value of the pressure-bonded ball diameter was 27 μm, and the thickness of the pressure-bonded ball was 11 μm.

［実施例３］
市販の純度９９．９９質量％以上のリン脱酸銅素材に、純度９９．９９質量％以上のニッケル（Ｎｉ）を１．０質量％、純度９９．９９９質量％以上の白金（Ｐｔ）を０．１質量％、純度９９．９９質量％以上のパラジウム（Ｐｄ）を０．０５質量％およびイオウ（Ｓ）を１質量ｐｐｍ、それぞれ配合して所定の銅合金線を得た。この合金を連続鋳造後、ダイヤモンドダイスを使用して、連続伸線加工し、直径１８μｍのワイヤを得た。その後、常温での伸び率が１２％となるように、最終連続焼鈍を約５５０℃にて行った。このワイヤを室温の大気中に３日間放置した後、この合金ワイヤの酸素濃度を測定したところ、３６質量ｐｐｍであった。このボンディングワイヤを実施例３とした。 [Example 3]
1.0% by mass of nickel (Ni) with a purity of 99.99% by mass or more and platinum (Pt) with a purity of 99.999% by mass or more are added to a commercially available phosphorus deoxidized copper material with a purity of 99.99% by mass or more. 0.1% by mass, 0.05% by mass of palladium (Pd) having a purity of 99.99% by mass or more and 1% by mass of sulfur (S) were blended to obtain a predetermined copper alloy wire. After continuous casting of this alloy, continuous drawing was performed using a diamond die to obtain a wire having a diameter of 18 μm. Then, final continuous annealing was performed at about 550° C. so that the elongation at room temperature was 12%. After leaving this wire in the atmosphere at room temperature for 3 days, the oxygen concentration of this alloy wire was measured and found to be 36 mass ppm. This bonding wire is referred to as Example 3.

（第一ボンドの接合性試験）
この実施例３のボンディングワイヤを実施例１と同様にして１００本ボンディングを行った。第一ボンドの全数の溶着状態を一般的な測定顕微鏡（オリンパス社製ＳＴＭ６）の対物レンズ５０倍で観察して目視で可と判断した。このボンディングワイヤの圧着ボールの代表的な５個の外観（「実施例３型」と称す）を図３に示す。圧着ボール径の平均値は２７μｍ、圧着ボール厚みは１１μｍであった。 (First bond bondability test)
100 pieces of the bonding wires of Example 3 were bonded in the same manner as in Example 1. The welded state of all the first bonds was observed with a general measuring microscope (STM6 manufactured by Olympus Co., Ltd.) with a 50× objective lens, and visually judged to be acceptable. FIG. 3 shows the appearance of five representative pressure-bonded balls of this bonding wire (referred to as “Example 3 type”). The average value of the pressure-bonded ball diameter was 27 μm, and the thickness of the pressure-bonded ball was 11 μm.

［実施例４］
市販の純度９９．９９９９質量％以上の電解銅素材に、純度９９．９９質量％以上のニッケル（Ｎｉ）を０．１質量％、純度９９．９９質量％以上の白金（Ｐｔ）を０．１質量％、イオウ（Ｓ）を１０質量ｐｐｍおよびリン（Ｐ）を１０質量ｐｐｍ、それぞれ配合して所定の銅合金線を得た。この合金を溶解鋳造後にて直径５ｍｍの鋳造材を製造した。 [Example 4]
0.1% by mass of nickel (Ni) having a purity of 99.99% by mass and 0.1% of platinum (Pt) having a purity of 99.99% by mass or more in a commercially available electrolytic copper material having a purity of 99.9999% by mass or more. Mass%, 10 mass ppm of sulfur (S) and 10 mass ppm of phosphorus (P) were blended to obtain a predetermined copper alloy wire. After casting this alloy, a cast material having a diameter of 5 mm was manufactured.

得られた各々の鋳造材について溝ロール、ダイヤモンドダイスを使用して、連続伸線加工した。なお、連続伸線加工途中の直径１００μｍで５００℃の熱処理を行い、その線径で常温の伸び率を測定すると１８％であった。その後に再度連続伸線加工を行い最終線径１８μｍのワイヤまで加工し、常温での伸び率が１３％となるように、最終連続焼鈍を約５５０℃にて行った。このワイヤを室温の大気中に３日間放置した後、この合金ワイヤの酸素濃度を測定したところ、２９質量ｐｐｍであった。このボンディングワイヤを実施例４とした。 Each of the obtained cast materials was subjected to continuous wire drawing using a groove roll and a diamond die. In addition, when heat treatment was performed at 500° C. with a diameter of 100 μm during continuous wire drawing, and the elongation at room temperature was measured with the wire diameter, it was 18%. After that, continuous wire drawing was performed again to wire up to a final wire diameter of 18 μm, and final continuous annealing was performed at about 550° C. so that the elongation at room temperature was 13%. After leaving this wire in the atmosphere at room temperature for 3 days, the oxygen concentration of this alloy wire was measured and found to be 29 mass ppm. This bonding wire is referred to as Example 4.

（第一ボンドの接合性試験）
この実施例３のボンディングワイヤを実施例１と同様にして１００本ボンディングを行った。第一ボンドの全数の溶着状態を一般的な測定顕微鏡（オリンパス社製ＳＴＭ６）の対物レンズ５０倍で観察して目視で可と判断した。このボンディングワイヤの圧着ボールの代表的な５個の外観（「実施例４型」と称す）を図４に示す。圧着ボール径の平均値は２８μｍ、圧着ボール厚みは１０μｍであった。 (First bond bondability test)
100 pieces of the bonding wires of Example 3 were bonded in the same manner as in Example 1. The welded state of all the first bonds was observed with a general measuring microscope (STM6 manufactured by Olympus Co., Ltd.) with a 50× objective lens, and visually judged to be acceptable. FIG. 4 shows the appearance of five representative pressure-bonded balls of this bonding wire (referred to as “Example 4 type”). The average value of the pressure-bonded ball diameter was 28 μm, and the thickness of the pressure-bonded ball was 10 μm.

［実施例５〜２４］
次に、合金成分の組成を変えて種々のボールボンディング用銅合金線（実施例５〜２４）を作製し、第一ボンドの接合性試験を行った。これらの結果を実施例１〜実施例４の範疇に属するものに分類し、表１に示す。 [Examples 5 to 24]
Next, various copper alloy wires for ball bonding (Examples 5 to 24) were prepared by changing the composition of alloy components, and the bondability test of the first bond was performed. These results are classified into those belonging to the categories of Examples 1 to 4 and shown in Table 1.

花びら形状の計測は、基本的に図６の図６−１〜図６−４のようにして行った。圧着ボールの形状は、図６−１のように外周部と内周部とからなる。この圧着ボールの中心軸を通る図６−１の内周部の中心点をMとし、Mを中心として内周部を取り囲むような円を図６−２のように実線で描いた。次に、図６−３のように、圧着ボールの外周部を実線Ｒでなぞった。そして、Ｍを中心にして外周部Ｒまでの半径Ｌを３６０度回転しながら求める。その後、図６−４に示すとおり、Ｌの最大値（Ｌ（Ｍａｘ））をほほ水平方向に表示し、Ｌの最小値（Ｌ（Ｍｉｎ））を右斜め上方に表示した。 The petal shape was basically measured as shown in FIGS. 6-1 to 6-4 in FIG. The pressure-bonded ball has an outer peripheral portion and an inner peripheral portion as shown in FIG. A center point of the inner peripheral portion of FIG. 6-1 which passes through the central axis of the pressure-bonded ball is defined as M, and a circle surrounding the inner peripheral portion with M at the center is drawn by a solid line as shown in FIG. 6-2. Next, as shown in FIG. 6C, the outer peripheral portion of the pressure bonded ball was traced by a solid line R. Then, the radius L to the outer peripheral portion R centering on M is calculated while rotating 360 degrees. Then, as shown in FIG. 6D, the maximum value of L (L(Max)) was displayed in a substantially horizontal direction, and the minimum value of L (L(Min)) was displayed diagonally to the upper right.

花びら形状は、経験的にＬ（Ｍｉｎ）とＬ（Ｍａｘ）の比率が３倍を超えた圧着形状とした。実施例および比較例では、１００個の圧着径の中から発生数の個数を計測した。また、比較例の中にはごく少量であるが、図７に示すような偏心した圧着ボールも含まれた。そこで、花びら形状の比較を容易にするため、Ｌ（Ｍｉｎ）が０となっている角度が３０度以上のものや、Ｌ（Ｍｉｎ）とＬ（Ｍａｘ）の比率が３倍を超えた状態が角度３０度以上連続しているものは、実施例および比較例の花びら形状のカウント数から除外した。実施例および比較例では、花びら形状の発生数が０個のものを◎、発生数が１〜３のものを○、そして、発生数が４個以上のものを×とした。これらの結果を表１右欄に示す。 The petal shape was empirically set to a crimped shape in which the ratio of L (Min) and L (Max) exceeded 3 times. In the examples and comparative examples, the number of occurrences was measured from 100 pressure bonded diameters. In addition, the comparative example also included an eccentric pressure-bonded ball as shown in FIG. 7, although the amount was very small. Therefore, in order to facilitate the comparison of petal shapes, there are cases where the angle at which L(Min) is 0 is 30 degrees or more, or when the ratio of L(Min) and L(Max) exceeds three times. Those having a continuous angle of 30 degrees or more were excluded from the petal-shaped counts of Examples and Comparative Examples. In Examples and Comparative Examples, the number of petal-shaped occurrences was 0, the number of occurrences of 1-3 was O, and the number of occurrences of 4 or more was X. The results are shown in the right column of Table 1.

０．８μｍ厚のアルミニウム（Ａｌ−０．５％Ｃｕ）電極膜のダメージは、ボールボンディング直後に割れが発生していないかを、１００個の電極膜で確認した。ボールボンディングされた状態でアルミニウム（Ａｌ）電極膜を上部から観察し、圧着されたボール周辺の電極膜に割れや盛り上がりのダメージが入っている個数を数え、０〜５個を○、６〜１０個を△、１１個以上を×とした。これらの結果を表１右欄に示す。 With respect to the damage of the aluminum (Al-0.5% Cu) electrode film having a thickness of 0.8 μm, it was confirmed by 100 electrode films whether or not a crack was generated immediately after ball bonding. The aluminum (Al) electrode film is observed from above in a ball-bonded state, and the number of cracked or raised damages on the electrode film around the pressure-bonded ball is counted. The number was set as Δ and the number of 11 or more was set as x. The results are shown in the right column of Table 1.

Figure 0006710141
Figure 0006710141

［比較例１］
市販の純度９９．９９９９質量％以上の電解銅素材に、純度９９．９９９質量％以上のニッケル（Ｎｉ）を０．０５質量％、純度９９．９９９質量％以上の白金（Ｐｔ）を０．０５質量％およびリン（Ｐ）を１２０質量ｐｐｍ配合して所定の銅合金線を得た。この合金を連続鋳造後、ダイヤモンドダイスを使用して、連続伸線加工し、直径１８μｍのワイヤを得た。その後、常温での伸び率が１１％となるように、最終連続焼鈍を約５００℃にて行った。 [Comparative Example 1]
0.05% by mass of nickel (Ni) with a purity of 99.999% by mass or more and 0.05% of platinum (Pt) with a purity of 99.999% by mass or more in a commercially available electrolytic copper material having a purity of 99.9999% by mass or more. Mass% and 120 mass ppm of phosphorus (P) were blended to obtain a predetermined copper alloy wire. After continuous casting of this alloy, continuous drawing was performed using a diamond die to obtain a wire having a diameter of 18 μm. Then, final continuous annealing was performed at about 500° C. so that the elongation at room temperature was 11%.

このワイヤを室温の大気中に３日間放置した後、この合金ワイヤの酸素濃度を測定したところ、３０質量ｐｐｍであった。このボンディングワイヤを比較例１とした。この比較例１はニッケル（Ｎｉ）と白金（Ｐｔ）の含有量が下限値を下回り、リン（Ｐ）の含有量が上限値を超えている。 After the wire was left in the air at room temperature for 3 days, the oxygen concentration of the alloy wire was measured and found to be 30 mass ppm. This bonding wire was used as Comparative Example 1. In Comparative Example 1, the contents of nickel (Ni) and platinum (Pt) are below the lower limit value, and the content of phosphorus (P) is above the upper limit value.

（第一ボンドの接合性試験）
この比較例１のボンディングワイヤを実施例１と同様にして１００本ボンディングを行った。第一ボンドの全数の溶着状態を一般的な測定顕微鏡（オリンパス社製ＳＴＭ６）の対物レンズ５０倍で観察して目視で不可と判断した。このボンディングワイヤの圧着ボールの代表的な５個の外観（「比較例型」と称す）を図５に示す。 (First bond bondability test)
100 bondings of the bonding wire of Comparative Example 1 were performed in the same manner as in Example 1. The welded state of all the first bonds was observed with a general measuring microscope (STM6 manufactured by Olympus Co., Ltd.) with a 50× objective lens, and visually judged to be impossible. FIG. 5 shows the appearance of five representative pressure balls of this bonding wire (referred to as “comparative example type”).

［比較例２〜５］
同様にして比較例２〜４のボールボンディング用銅合金線を作製し、第一ボンドの接合性試験を行った。これらの組成と結果を表１に示す。比較例２は、白金（Ｐｔ）の含有量が上限値を超えている。また、リン（Ｐ）の含有量が下限値を下回っている。比較例３は、酸素（Ｏ）の含有量が上限値を超え、かつ、イオウ（Ｓ）の含有量が下限値を下回っている。比較例４は、パラジウム（Ｐｄ）の含有量が下限値を下回り、かつ、イオウ（Ｓ）の含有量が上限値を超えている。 [Comparative Examples 2 to 5]
Similarly, the copper alloy wires for ball bonding of Comparative Examples 2 to 4 were produced, and the bondability test of the first bond was performed. The compositions and results are shown in Table 1. In Comparative Example 2, the content of platinum (Pt) exceeds the upper limit value. Further, the content of phosphorus (P) is below the lower limit value. In Comparative Example 3, the content of oxygen (O) exceeds the upper limit value, and the content of sulfur (S) is less than the lower limit value. In Comparative Example 4, the content of palladium (Pd) is below the lower limit and the content of sulfur (S) exceeds the upper limit.

図１〜図５および表１の結果から明らかなように、本発明の実施例１〜２４のボールボンディング用銅合金線においては、銅合金線を細くして溶融ボールを小さくしても、圧着ボール形状が安定し、圧着ボールが花びら状に拡がらないことがわかる。図１〜図５で示すように、圧着ボール形状が良かった順序は、実施例１型≒実施例２型≒実施例３型＞実施例４型＞比較例１型の順序であった。図１〜図５では判読しにくいが、特に実施例１および実施例２の銅合金線がボンディングワイヤとして優れていることがわかる。このことは図１〜図５に例示されているとおりである。 As is clear from the results of FIGS. 1 to 5 and Table 1, in the copper alloy wires for ball bonding of Examples 1 to 24 of the present invention, even if the copper alloy wires are thinned to make the molten balls small, pressure bonding is performed. It can be seen that the ball shape is stable and the pressure-bonded ball does not spread like petals. As shown in FIGS. 1 to 5, the order in which the crimped ball shape was good was the order of Example 1 type≈Example 2 type≈Example 3 type>Example 4 type>Comparative example 1 type. Although it is difficult to read in FIGS. 1 to 5, it can be seen that the copper alloy wires of Examples 1 and 2 are particularly excellent as bonding wires. This is as illustrated in FIGS.

他方、表１の結果から明らかなように、比較例１〜４のボールボンディング用銅合金線は、圧着ボール形状が安定せず、圧着ボールが花びら状に拡がっていることがわかる。このことは、図５にも例示されているように、圧着ボール形状が花びら状に観察されることからも理解できる。また、比較例２はアルミニウム電極膜のダメージ発生数が実施例よりも著しく多いことがわかる。 On the other hand, as is clear from the results in Table 1, the copper alloy wires for ball bonding of Comparative Examples 1 to 4 are not stable in the shape of the pressure-bonded ball, and the pressure-bonded ball spreads like a petal. This can be understood from the fact that the pressure-bonded ball shape is observed in a petal shape as illustrated in FIG. Further, it can be seen that in Comparative Example 2, the number of occurrences of damage to the aluminum electrode film is significantly higher than that in the Examples.

本発明ボールボンディング用銅合金線は、携帯電話といった携帯用電子機器、自動車などに載置される電子部品、医療機器、産業用ロボットなどの各種の電気・電子機器に組み込まれる半導体装置のボンディングワイヤのみならず、これらの電気・電子機器の電線、代表的には同軸ケーブルの極細線に好適に利用することができる。

The copper alloy wire for ball bonding of the present invention is a bonding wire for a semiconductor device incorporated in various electric/electronic devices such as portable electronic devices such as mobile phones, electronic parts mounted on automobiles, medical devices, industrial robots and the like. In addition, it can be suitably used for electric wires of these electric/electronic devices, typically, ultrafine wires of coaxial cables.

Claims (6)

ボールボンディング用ワイヤにおいて、０．１〜１．５質量％のニッケル（Ｎｉ）、白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に０．１〜２０質量ｐｐｍのイオウ（Ｓ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とするボールボンディング用銅合金線。 In the ball bonding wire, 0.1 to 1.5% by mass of nickel (Ni), platinum (Pt), or palladium (Pd) in total of 0.01 to 1.5% by mass. And a copper alloy wire for ball bonding, further comprising 0.1 to 20 mass ppm of sulfur (S), 10 to 80 mass ppm of oxygen (O), and the balance copper (Cu). ボールボンディング用ワイヤにおいて、０．１〜１．５質量％のニッケル（Ｎｉ）、白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に１０〜１００質量ｐｐｍのリン（Ｐ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とするボールボンディング用銅合金線。 In the ball bonding wire, 0.1 to 1.5% by mass of nickel (Ni), platinum (Pt), or palladium (Pd) in total of 0.01 to 1.5% by mass. And a copper alloy wire for ball bonding, further comprising 10 to 100 mass ppm of phosphorus (P), 10 to 80 mass ppm of oxygen (O), and the balance copper (Cu). ボールボンディング用ワイヤにおいて、０．１〜１．５質量％のニッケル（Ｎｉ）、白金（Ｐｔ）またはパラジウム（Ｐｄ）のうちのいずれか１種以上を合計で０．０１〜１．５質量％、更に０．１〜２０質量ｐｐｍのイオウ（Ｓ）、１０〜１００質量ｐｐｍのリン（Ｐ）、１０〜８０質量ｐｐｍの酸素（Ｏ）および残部銅（Ｃｕ）からなることを特徴とするボールボンディング用銅合金線 In the ball bonding wire, 0.1 to 1.5% by mass of nickel (Ni), platinum (Pt), or palladium (Pd) in total of 0.01 to 1.5% by mass. A ball characterized by further comprising 0.1 to 20 mass ppm of sulfur (S), 10 to 100 mass ppm of phosphorus (P), 10 to 80 mass ppm of oxygen (O), and the balance copper (Cu). Copper alloy wire for bonding 上記ニッケル（Ｎｉ）の含有量が０．２〜１．２質量％であることを特徴とする請求項１〜請求項３のいずれかに記載のボールボンディング用銅合金線。 Content of the said nickel (Ni) is 0.2-1.2 mass %, The copper alloy wire for ball bonding in any one of the Claims 1-3 characterized by the above-mentioned. 上記白金（Ｐｔ）またはパラジウム（Ｐｄ）の含有量が０．０５〜０．８質量％であることを特徴とする請求項１〜請求項３のいずれかに記載のボールボンディング用銅合金線 Content of the said platinum (Pt) or palladium (Pd) is 0.05-0.8 mass %, The copper alloy wire for ball bonding in any one of the Claims 1-3 characterized by the above-mentioned. 上記イオウ（Ｓ）の含有量が２〜１０質量ｐｐｍであることを特徴とする請求項１または請求項３のいずれかに記載のボールボンディング用銅合金線。
Content of the said sulfur (S) is 2-10 mass ppm, The copper alloy wire for ball bonding in any one of Claim 1 or Claim 3 characterized by the above-mentioned.
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