TWI602934B - Ball welding with gold (Au) to disperse the copper wire - Google Patents

Ball welding with gold (Au) to disperse the copper wire Download PDF

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TWI602934B
TWI602934B TW105117168A TW105117168A TWI602934B TW I602934 B TWI602934 B TW I602934B TW 105117168 A TW105117168 A TW 105117168A TW 105117168 A TW105117168 A TW 105117168A TW I602934 B TWI602934 B TW I602934B
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gold
wire
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TW201708551A (en
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Hiroyuki Amano
Syuichi Mitoma
takuya Hamamoto
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Tanaka Electronics Ind
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
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    • H01L2224/456—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45638—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/45644—Gold (Au) as principal constituent
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    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
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    • H01L2224/45599—Material
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    • H01L2224/85009—Pre-treatment of the connector or the bonding area
    • H01L2224/8503—Reshaping, e.g. forming the ball or the wedge of the wire connector
    • H01L2224/85035—Reshaping, e.g. forming the ball or the wedge of the wire connector by heating means, e.g. "free-air-ball"
    • H01L2224/85045—Reshaping, e.g. forming the ball or the wedge of the wire connector by heating means, e.g. "free-air-ball" using a corona discharge, e.g. electronic flame off [EFO]
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  • Engineering & Computer Science (AREA)
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  • Wire Bonding (AREA)

Description

球焊用金(Au)分散銅線 Gold (Au) dispersion copper wire for ball bonding

本發明係關於球焊用金(Au)分散銅線，其適用於半導體裝置中所使用的IC晶片電極與外部引線等的基板的連接；特別是關於即使係15μm以下的極細線，亦可得到穩定熔融焊球的被覆銅線。 The present invention relates to a gold (Au) dispersion copper wire for ball bonding, which is suitable for connection between an IC wafer electrode used in a semiconductor device and a substrate such as an external lead; in particular, it is possible to obtain an ultrafine wire of 15 μm or less. Stabilizing the coated copper wire of the molten solder ball.

一般而言，針對被覆銅接合線與電極的第一接合，係使用稱為焊球接合的方式，而針對被覆銅接合線與半導體用電路配線基板上之配線的第二接合，係使用稱為楔型接合的方式。該第一接合之中，藉由放電結球(electronic frame off,EFO)的方式，對被覆銅接合線的前端施予電弧加熱，藉此使該前端部熔融之後，利用表面張力使熔融物凝固，而在接合線的前端形成稱為焊球(FAB；free air ball)的正球體。接著，在150~300℃的範圍內，一邊將該初期焊球與該電極加熱，一邊施加超音波，以進行壓接，藉此將其接合於晶片上的鋁墊(參照第一圖)。 In general, the first bonding of the coated copper bonding wire and the electrode is performed by a method called solder ball bonding, and the second bonding of the wiring on the coated copper bonding wire and the semiconductor circuit wiring substrate is called The way wedges are joined. In the first bonding, the front end of the covered copper bonding wire is subjected to arc heating by means of an electronic frame off (EFO), whereby the front end portion is melted, and then the melt is solidified by surface tension. A positive sphere called a free air ball (FAB) is formed at the front end of the bonding wire. Next, an ultrasonic pad is applied while heating the initial solder ball and the electrode in a range of 150 to 300 ° C to bond it to the aluminum pad on the wafer (see the first drawing).

此處，形成熔融焊球的第一接合中，為了抑制銅的氧化，一般係使用下述的焊球方式：一邊對於接合線吹以氮為主體的氣體或含5%之氫氣的氮氣，一邊使接合線的前端進行火花放電，藉此形成熔融焊球。該方式或以該方式所形成的熔融焊球稱為FAB。 Here, in the first bonding in which the molten solder balls are formed, in order to suppress the oxidation of copper, a solder ball method in which a gas mainly composed of nitrogen or a nitrogen gas containing 5% of hydrogen is blown to the bonding wire is used. The tip end of the bonding wire is subjected to spark discharge, thereby forming a molten solder ball. This method or the molten solder ball formed in this manner is called FAB.

以往將半導體裝置的IC晶片電極與外部引線連接的鈀(Pd)被覆銅線，在日本實開昭60-160554號公報(後述專利文獻1)中，即有人提出 一種半導體用接合細線，其特徵為「在Cu或是Cu合金的芯線外圍直接或是隔著中間層設置Pd或是Pd合金的被覆層」。之後，實用的鈀(Pd)被覆銅線，在日本特開2004-014884號公報(後述專利文獻2)中，有人提出一種接合線，其係具有芯材以及形成於芯材上之被覆層的接合線，其特徵為「該芯材係以顯微維式硬度在80Hv以下的金以外的材料所構成，而該被覆層係由熔點高於芯材之熔點300℃以上、且抗氧化性優於銅的金屬所構成」，再者，2002年3月發行的SEI Technical Review雜誌第160號之中，介紹「接合線的開發」。亦具有解析該芯材與被覆層之界面的專利申請案(日本特開2010-272884號公報等)。 In the past, a palladium (Pd)-coated copper wire in which an IC chip electrode of a semiconductor device is connected to an external lead is proposed in Japanese Laid-Open Patent Publication No. 60-160554 (Patent Document 1 to be described later). A bonding thin wire for a semiconductor, which is characterized in that "a coating layer of Pd or a Pd alloy is provided directly on the periphery of a core of Cu or a Cu alloy or via an intermediate layer". After that, a palladium (Pd)-coated copper wire is used, and a bonding wire having a core material and a coating layer formed on the core material is proposed in JP-A-2004-014884 (Patent Document 2 to be described later). The bonding wire is characterized in that "the core material is composed of a material other than gold having a microscopic hardness of 80 Hv or less, and the coating layer has a melting point higher than a melting point of the core material of 300 ° C or more, and is excellent in oxidation resistance. In the SEI Technical Review magazine No. 160 issued in March 2002, "The development of bonding wires" was introduced. There is also a patent application for analyzing the interface between the core material and the coating layer (JP-A-2010-272884, etc.).

然而，鈀(Pd)外露的這種無雜質的鈀(Pd)被覆銅線，因為拉線模具(wire drawing dies)的磨耗嚴重，且線材的解繞性亦不佳，故並非係適合大量生產的材料。再者，即使量產無雜質的鈀(Pd)被覆銅線，若連續形成FAB，則具有熔融焊球不穩定的缺點。亦即，無雜質的鈀(Pd)被覆銅線，在形成熔融焊球時，具有容易發生焊球易成為長矛狀之問題的缺點。 However, this impurity-free palladium (Pd) exposed by palladium (Pd) is coated with copper wire, and the wire drawing dies are not suitable for mass production because of the severe abrasion of the wire drawing dies and the unwinding of the wire. s material. Further, even if the palladium (Pd) coated copper wire is produced in an amount of no impurities, if the FAB is continuously formed, the molten solder ball is unstable. That is, the palladium (Pd)-free copper wire is free from impurities, and when the molten solder ball is formed, there is a disadvantage that the solder ball tends to be a spear-like problem.

因此，日本特開2005-167020號公報(後述專利文獻3)中提出一種接合線之發明，其特徵為：使金(Au)最表面的熔點低於鈀(Pd)被覆層，並使金(Au)被覆層的厚度比鈀(Pd)被覆層薄，且為線徑的0.002倍以下(同公報的請求項8)。接著，一般的FAB係採用下述方式：接合線前端與電弧炬(arc torch)前端所形成之角度，係從線材長邊方向的60度以內，而於該電弧炬與線材前端之間形成電弧放電，以形成焊球部，再將該焊球部連接於電極上。若使用上述的金(Au)最表面被覆線材，則藉由電弧放電之尖端以最短距離到達金(Au)，確認FAB的形狀穩定(參照日本特開2011-146754號公報)。 For this reason, Japanese Laid-Open Patent Publication No. 2005-167020 (Patent Document 3 to be described later) proposes an invention of a bonding wire characterized in that the melting point of the outermost surface of gold (Au) is lower than that of the palladium (Pd) coating layer, and gold ( The thickness of the Au) coating layer is thinner than the palladium (Pd) coating layer and is 0.002 times or less the wire diameter (Requirement 8 of the same publication). Next, the general FAB system adopts the following method: the angle formed by the front end of the bonding wire and the front end of the arc torch is within 60 degrees of the longitudinal direction of the wire, and an arc is formed between the arc torch and the front end of the wire. Discharge to form a solder ball portion, and then connect the solder ball portion to the electrode. When the gold-coated (Au) outermost-coated wire is used, the gold (Au) is reached by the tip of the arc discharge at the shortest distance, and the shape of the FAB is confirmed to be stable (refer to Japanese Laid-Open Patent Publication No. 2011-146754).

如此，被覆有金(Au)的鈀(Pd)被覆銅線，具有「與FAB之潤濕性良好、熔融焊球容易黏附於根部未熔融之線材」的傾向。因此，其後開發了「連續拉線至最終膜厚到達1~9nm為止」的金(Au)被覆線材(日本特開2012-036490號公報(後述專利文獻4))。然而，若以鑽石拉線模對接合線進行連續拉線，則因為模具的磨耗導致線徑增大，使得奈米等級的金(Au)被覆層變得不均勻。因此，若欲將最表面之金(Au)被覆層的膜厚控制在數奈米(nm)單位，則最終難以維持並管理模具，且更換模具等的手續繁雜。 As described above, the gold (Au)-coated palladium (Pd)-coated copper wire tends to have "good wettability with FAB, and the molten solder ball tends to adhere to the wire which is not melted at the root portion". Therefore, a gold (Au) coated wire material which is "continuously drawn until the final film thickness reaches 1 to 9 nm" has been developed (Japanese Laid-Open Patent Publication No. 2012-036490 (Patent Document 4)). However, if the bonding wire is continuously drawn by the diamond drawing die, the wire diameter is increased due to the abrasion of the die, so that the nano-grade Au (Au) coating layer becomes uneven. Therefore, if the film thickness of the gold (Au) coating layer on the outermost surface is to be controlled in units of several nanometers (nm), it is difficult to maintain and manage the mold, and the procedure for replacing the mold or the like is complicated.

另一方面，有人開發一種最表面的金(Au)被覆膜的技術，其利用「使中間層的鈀侵入金極薄層，並使微細之金相與鈀相3維成長」的Stranski-Krastanov成長(日本特開2013-131654號公報(後述專利文獻5))。利用Au的原子半徑與Pd的原子半徑接近，而使鈀(Pd)膜從金(Au)被覆膜上以山形成長。該技術中，金(Au)被覆膜與鈀(Pd)層的厚度關係極為重要。 On the other hand, a technique for producing a gold (Au) coating film on the outermost surface has been developed, in which Stranski- is used to "invert the palladium of the intermediate layer into the gold thin layer and grow the fine metal phase and the palladium phase three-dimensionally". The growth of the Krastanov is disclosed in Japanese Laid-Open Patent Publication No. 2013-131654 (Patent Document 5). The atomic radius of Au is close to the atomic radius of Pd, and the palladium (Pd) film is formed long from the gold (Au) coating film. In this technique, the relationship between the thickness of the gold (Au) coating film and the palladium (Pd) layer is extremely important.

然而，若因為模具磨耗造成金(Au)被覆膜不均勻，則該不均勻之處無法依照厚度關係，導致鈀(Pd)膜未成長，或是金(Au)被覆膜會擴散至鈀(Pd)層中。再者，在最後以鑽石拉線模進行處理的情況中，該模具的痕跡轉印至線材，而殘留條紋狀溝槽，進而在該處留有較厚的金(Au)被覆層。因此，依然留有若以FAB形成熔融焊球，則熔融焊球沿著條紋狀溝槽的未熔融的金(Au)被覆層爬升，進而黏附於線材，導致熔融焊球不穩定的課題。 However, if the gold (Au) coating film is uneven due to mold wear, the unevenness cannot be in accordance with the thickness relationship, resulting in the palladium (Pd) film not growing, or the gold (Au) coating film diffusing to the palladium. In the (Pd) layer. Further, in the case where the diamond wire drawing die is finally processed, the trace of the mold is transferred to the wire, and the striped groove remains, and a thick gold (Au) coating layer is left there. Therefore, if the molten solder ball is formed by FAB, the molten solder ball climbs along the unmelted gold (Au) coating layer of the stripe-shaped groove and adheres to the wire, which causes the molten solder ball to be unstable.

【先前技術文獻】 [Previous Technical Literature] 【專利文獻】 [Patent Literature]

專利文獻1 日本實開昭60-160554號公報 Patent Document 1 Japanese Unexamined Patent Publication No. SHO 60-160554

專利文獻2 日本特開2004-014884號公報 Patent Document 2 Japanese Patent Laid-Open Publication No. 2004-014884

專利文獻3 日本特開2005-167020號公報 Patent Document 3 Japanese Patent Laid-Open Publication No. 2005-167020

專利文獻4 日本特開2012-036490號公報 Patent Document 4 Japanese Patent Laid-Open Publication No. 2012-036490

專利文獻5 日本特開2013-131654號公報 Patent Document 5 Japanese Patent Laid-Open Publication No. 2013-131654

本發明之目的係用以解決量產之接合線的EFO造成熔融焊球沿著線材爬升的上述課題，而提供一種球焊用金(Au)分散銅線，無論其是在量產開始後使用全新鑽石拉線模所製造的線材，或是拉線10萬公尺以上之後的更換前的模具所製造的線材，皆可藉由相同放電條件形成穩定熔融焊球。 The purpose of the present invention is to solve the above problem that the EFO of the mass-produced bonding wire causes the molten solder ball to climb along the wire, and to provide a gold (Au) dispersion copper wire for ball bonding, whether it is used after mass production starts. The wire made by the new diamond wire drawing die, or the wire made by the mold before the replacement of the wire 100,000 meters or more, can form a stable molten solder ball by the same discharge condition.

本案發明人發現，若使最表面的金(Au)表皮層的膜厚薄至某個程度，再藉由適當的最終調質熱處理，則可具有使最表面的金(Au)以粒子狀分散、排列於鈀(Pd)被覆層上而以無數點狀存在」的介穩區域。可將該介穩區域視為「在極薄之金(Au)的表皮層中被拉伸的金(Au)原子彼此的機械鍵結因為熱而緩和」的金(Au)金屬之間的鍵結。再者，該介穩區域，主要係藉由線材的線徑以及所被覆之鈀(Pd)的表面性狀來決定。適合該介穩區域的溫度範圍的幅度較小。例如，僅從介穩區域的開始溫度上升+50℃，則該介穩區域消失，而最表面的金(Au)則埋入鈀(Pd)被覆層中。再者，適合介穩區域的溫度範圍，根據鈀(Pd)被覆層係以「乾式鍍敷所形成」或是「藉由氰化浴或非氰化浴的濕式鍍敷形成」，而有所不同。本案發明人，根據這樣的發現而完成本發明。 The inventors of the present invention have found that if the film thickness of the outermost gold (Au) skin layer is made thin to some extent and then subjected to an appropriate final heat treatment, the outermost surface gold (Au) can be dispersed in the form of particles. A metastable region that is arranged on the palladium (Pd) coating layer and exists in a myriad of dots. The metastable region can be regarded as a bond between gold (Au) metals in which the mechanical bonding of gold (Au) atoms stretched in the skin layer of the ultrathin gold (Au) is moderated by heat. Knot. Furthermore, the metastable region is mainly determined by the wire diameter of the wire and the surface properties of the coated palladium (Pd). The temperature range suitable for the metastable region is small. For example, only when the temperature rises from the onset of the metastable region by +50 ° C, the metastable region disappears, and the outermost gold (Au) is buried in the palladium (Pd) coating layer. Furthermore, the temperature range suitable for the metastable region is based on whether the palladium (Pd) coating layer is formed by "dry plating" or "wet plating by cyanide bath or non-cyanide bath". Different. The inventors of the present invention have completed the present invention based on such findings.

用以解決本發明之課題的球焊用金(Au)分散銅線，其特徵為：在銅(Cu)純度99.9質量%以上之銅合金所構成的芯材上形成鈀(Pd)的被覆層及金(Au)的表皮層、且線徑10~25μm的球焊用鈀(Pd)被覆銅線之中，對於該金(Au)的表皮層中的金(Au)進行化學分析所得到的理論膜厚在0.1奈米(nm)以上10奈米(nm)以下，且以電子微探儀(EPMA)進行表面分析所得到的金(Au)的分布，係該金(Au)微粒子以無數的點狀分布於該鈀(Pd)被覆層上。 A gold (Au) dispersion copper wire for ball bonding for solving the problem of the present invention is characterized in that a coating layer of palladium (Pd) is formed on a core material composed of a copper alloy having a copper (Cu) purity of 99.9% by mass or more. A chemical analysis of gold (Au) in the skin layer of the gold (Au) in a skin layer of gold (Au) and a palladium (Pd) coated copper wire having a wire diameter of 10 to 25 μm. The theoretical film thickness is 0.1 nm or less (10 nm) or more and 10 nm or less, and the distribution of gold (Au) obtained by surface analysis by an electronic micro-survey (EPMA) is such that the gold (Au) fine particles are countless The dots are distributed on the palladium (Pd) coating layer.

本發明的較佳實施態樣如以下所述。 Preferred embodiments of the invention are as follows.

該銅合金，較佳係含有3質量ppm以上500質量ppm以下的磷(P)。再者，該銅合金，較佳係含有50質量ppm以上500質量ppm以下的金(Au)。再者，該銅合金，較佳係含有0.2質量ppm以上100質量ppm以下的磷(P)及金(Au)以外的金屬元素。再者，該銅合金，較佳係含有3質量ppm以上500質量ppm以下的磷(P)、50質量ppm以上500質量ppm以下的金(Au)、0.2質量ppm以上100質量ppm以下的其他金屬元素，且該等元素的總量小於1,000ppm。再者，該理論的膜厚較佳在2奈米(nm)以下。 The copper alloy preferably contains phosphorus (P) in an amount of 3 ppm by mass or more and 500 ppm by mass or less. Further, the copper alloy preferably contains 50 mass ppm or more and 500 mass ppm or less of gold (Au). Further, the copper alloy preferably contains 0.2 ppm by mass or more and 100 ppm by mass or less of a metal element other than phosphorus (P) and gold (Au). Further, the copper alloy preferably contains phosphorus (P) in an amount of 3 ppm by mass or more and 500 ppm by mass or less, gold (Au) in an amount of 50 ppm by mass or more and 500 ppm by mass or less, and other metals in an amount of 0.2 ppm by mass or more and 100 ppm by mass or less. Element, and the total amount of these elements is less than 1,000 ppm. Further, the theoretical film thickness is preferably 2 nm or less.

本發明中，如前所述的「理論膜厚」，係因為最表面的金(Au)表皮層的膜厚無法實際測量而衍伸出來的概念。亦即，藉由重量分析法，並藉由化學分析求得金(Au)在接合線整體之中所佔的比例。接著，從該求得的值，假設接合線的剖面為正圓，並且假設其線徑的最表面被金(Au)均勻被覆，以算出膜厚。由於奈米尺寸的等級，於實際的接合線的表面上具有凹凸，故該理論的膜厚值有可能小於金(Au)的原子半徑。 In the present invention, the "theoretical film thickness" as described above is a concept in which the film thickness of the outermost gold (Au) skin layer cannot be actually measured. That is, the proportion of gold (Au) in the entire bonding wire is obtained by gravimetric analysis and chemical analysis. Next, from the obtained values, it is assumed that the cross section of the bonding wire is a perfect circle, and the outermost surface of the wire diameter is assumed to be uniformly covered with gold (Au) to calculate the film thickness. Since the grade of the nanometer size has irregularities on the surface of the actual bonding wire, the theoretical film thickness value may be smaller than the atomic radius of gold (Au).

再者，「化學分析」係下述的分析方法：溶解金(Au)分散銅線整體，再藉由高頻感應耦合電漿(ICP)發光分光分析法-電子微探儀 (EPMA)，求得該溶液中的金(Au)濃度。再者，最表面的金(Au)「被覆層」及「表皮層」中的「層」的表述，係方便以「層」來表示金(Au)微粒子存在的範圍。 Furthermore, "chemical analysis" is the following analysis method: dissolving gold (Au) dispersed copper wire as a whole, and then by high-frequency inductively coupled plasma (ICP) luminescence spectrometry - electronic micro-probe (EPMA), the gold (Au) concentration in the solution was determined. Furthermore, the expression of the "layer" in the gold (Au) "coating layer" and the "skin layer" on the outermost surface is convenient for expressing the range in which gold (Au) fine particles exist in the "layer".

再者，藉由電子微探儀(EPMA)表面分析，將該金(Au)微粒子的分布係以無數點狀分布作為特徵，是因為該金(Au)微粒子若大至某個程度則可以目視確認，但亦具有過小而無法以目視確認的情況。另外可得知，在電子微探儀(EPMA)表面分析之中，尺寸大至某個程度的金(Au)微粒子，在以相同分析所得到的Pd的分布中，於該金(Au)微粒子的位置不會檢測出Pd(參照第二圖及第三圖)。 Furthermore, the surface distribution of the gold (Au) microparticles is characterized by an innumerable dot distribution by surface analysis of an electronic microprobe (EPMA) because the gold (Au) microparticles can be visually observed to a certain extent. Confirmation, but it is also too small to be visually confirmed. In addition, it can be known that in the surface analysis of an electronic micro-survey (EPMA), gold (Au) fine particles having a size as large as a certain amount are distributed in the gold (Au) fine particles in the distribution of Pd obtained by the same analysis. The position does not detect Pd (refer to the second and third figures).

本發明的球焊用金(Au)分散銅線中，以該金(Au)的化學分析所得到的理論膜厚在0.1奈米(nm)以上10奈米(nm)以下。使上限在10奈米(nm)以下，是因為最表面的金(Au)被覆層的膜厚不以所謂具有厚度的「層」的形式存在，而是以「金(Au)微粒子以無數點狀分布於該鈀(Pd)被覆層上」作為構成要件。因為金(Au)的導電性優於鈀(Pd)，故火花放電到達該金(Au)微粒子會使得FAB穩定。再者，藉由將經延伸的金(Au)層改質為金(Au)微粒子的狀態，亦可使金(Au)微粒子的化學活性穩定。 In the gold (Au) dispersion copper wire for ball bonding of the present invention, the theoretical film thickness obtained by chemical analysis of the gold (Au) is 0.1 nm (nm) or more and 10 nm (nm) or less. The upper limit is made 10 nm or less because the film thickness of the outermost gold (Au) coating layer does not exist in the form of a so-called "layer" having a thickness, but the "gold (Au) particles are innumerable points. It is distributed on the palladium (Pd) coating layer as a constituent element. Since the conductivity of gold (Au) is superior to that of palladium (Pd), the spark discharge reaches the gold (Au) particles, which makes the FAB stable. Further, the chemical activity of the gold (Au) fine particles can be stabilized by changing the stretched gold (Au) layer to the gold (Au) fine particles.

金(Au)被覆層的膜厚若超過10奈米(nm)、則因為膜厚的不均勻性，導致火花放電到達之處不均勻，進而使FAB不穩定。若藉由以均質熱處理等進行鈀(Pd)膜的熱成長，結果導致金(Au)被覆層的膜厚更加不均勻。使下限在0.1奈米(nm)以上，是為了使金(Au)微粒子以無數點狀分布在該鈀(Pd)被覆層上。若小於下限，則金(Au)微粒子無法以無數點狀分布。 When the film thickness of the gold (Au) coating layer exceeds 10 nanometers (nm), the unevenness of the film thickness causes the spark discharge to be uneven, and the FAB is unstable. When the palladium (Pd) film is thermally grown by a homogeneous heat treatment or the like, the film thickness of the gold (Au) coating layer is more uneven. The lower limit is made 0.1 nm or more in order to distribute gold (Au) fine particles on the palladium (Pd) coating layer in a myriad of dots. If it is less than the lower limit, gold (Au) fine particles cannot be distributed in a myriad of dots.

若具有金(Au)微粒子未以點狀分布於該鈀(Pd)被覆層上的 區域，則火花放電到達之處不均勻，導致FAB不穩定。此處，金(Au)微粒子以「無數點狀存在」，係指即使在作為模具痕跡的條紋狀溝槽之上，亦分散有金(Au)微粒子的狀態。藉由適當溫度的最終熱處理，被覆於最表面的金(Au)原子平面式地聚集，而形成微粒子。若高於該適當溫度，則金(Au)原子分散於鈀(Pd)被覆層中，而產生所謂的擴散現象，導致金(Au)微粒子消失。 If gold (Au) particles are not distributed in dots on the palladium (Pd) coating layer In the area, the spark discharge is not uniform, resulting in FAB instability. Here, the gold (Au) fine particles are present in "innumerable dots", and are in a state in which gold (Au) fine particles are dispersed even on the stripe-shaped grooves which are mold marks. The gold (Au) atoms coated on the outermost surface are planarly aggregated by the final heat treatment at an appropriate temperature to form fine particles. When it is higher than the appropriate temperature, gold (Au) atoms are dispersed in the palladium (Pd) coating layer, and a so-called diffusion phenomenon occurs, resulting in the disappearance of gold (Au) fine particles.

基於以下理由，使理論膜厚在2奈米(nm)以下較佳。 The theoretical film thickness is preferably 2 nm or less for the following reasons.

一般而言，若金(Au)的膜厚加厚至數百奈米，而能夠以歐傑分光分析裝置在深度方向的分析進行實測，則可觀察到所謂的匍匐現象，該匍匐現象，係熔融焊球浸潤位於熔融焊球根部之線材表面的金(Au)膜，而因為熔融焊球的表面張力，導致其在未熔融的線材表面爬升。另一方面，若金(Au)的膜厚的實測值在50奈米(nm)以下，則成為理論膜厚的區域，而不會觀察到這樣的匍匐現象。 In general, if the film thickness of gold (Au) is thickened to several hundred nanometers and can be measured by the analysis of the depth direction of the Oujie spectroscopic analysis device, the so-called 匍匐 phenomenon can be observed. The molten solder ball infiltrates the gold (Au) film on the surface of the wire of the molten solder ball, and because of the surface tension of the molten solder ball, it climbs on the surface of the unmelted wire. On the other hand, if the measured value of the film thickness of gold (Au) is 50 nm or less, it becomes a region of the theoretical film thickness, and such a flaw phenomenon is not observed.

然而，即使在50奈米(mm)以下的範圍，只要是金(Au)的理論膜厚較厚的區域，金(Au)微粒子以無數點狀存在的現象會因為最終的調質熱處理而消失，而難以控制金(Au)的膜厚。因此，為了在以1個最終鑽石拉線模長期進行拉線的情況下，亦可穩定地使金(Au)微粒子以無數點狀存在，金(Au)的膜厚要越薄越好。因此，理論膜厚在2奈米(nm)以下。 However, even in the range of 50 nm or less, as long as the theoretical film thickness of gold (Au) is thick, the phenomenon that gold (Au) particles are present in a myriad of dots disappears due to the final heat treatment. It is difficult to control the film thickness of gold (Au). Therefore, in order to carry out the wire drawing for a long time in one final diamond wire drawing die, the gold (Au) fine particles can be stably present in a plurality of dots, and the film thickness of gold (Au) is preferably as thin as possible. Therefore, the theoretical film thickness is below 2 nm (nm).

再者，本發明的球焊用金(Au)分散銅線中，金(Au)及鈀(Pd)所構成的貴金屬被覆層，一般而言在1微米(μm)以下，其相對於接合線之線徑的10~25μm，幾乎係可無視的厚度。因此，即使藉由FAB形成熔融焊球，亦不會受到被覆層之膜厚的影響。然而，因為存在該抗氧化性的鈀(Pd)被覆層，故芯材的銅線不會因大氣中的氧氣而被氧化。因此，與習知的銅(Cu) 的純度在99.9質量%以上的銅合金所構成的芯材組成相同，本發明的球焊用金(Au)分散銅線，其熔融焊球成為正球形，而可將其接合至鋁墊。 Further, in the gold (Au) dispersion copper wire for ball bonding of the present invention, the noble metal coating layer composed of gold (Au) and palladium (Pd) is generally 1 micrometer (μm) or less with respect to the bonding wire. The wire diameter is 10 to 25 μm, which is almost a thickness that can be ignored. Therefore, even if the molten solder ball is formed by the FAB, it is not affected by the film thickness of the coating layer. However, since the oxidation-resistant palladium (Pd) coating layer is present, the copper wire of the core material is not oxidized by oxygen in the atmosphere. Therefore, with the conventional copper (Cu) The core material composition of the copper alloy having a purity of 99.9% by mass or more is the same, and the gold (Au) dispersion copper wire for ball bonding of the present invention has a molten spherical ball which is formed into a true spherical shape and can be bonded to the aluminum pad.

再者，即使在拉線到最終線徑之後，再被覆鈀(Pd)及金(Au)之貴金屬的被覆材料，亦無法達成本發明的目的。這是因為，最終的被覆層無法填埋不規則的縱長型溝槽，而無法形成本發明之理論膜厚的金(Au)的表皮層。本發明之極薄表皮層的形成，雖亦與芯材及被覆材的組合種類相關，但一般而言，拉線步驟中線材的直徑必須縮徑1/10以上。 Further, even after the wire is pulled to the final wire diameter, the coating material of the noble metal of palladium (Pd) and gold (Au) is coated, and the object of the present invention cannot be achieved. This is because the final coating layer cannot fill the irregular elongated groove, and the gold (Au) skin layer of the theoretical film thickness of the present invention cannot be formed. The formation of the extremely thin skin layer of the present invention is also related to the type of combination of the core material and the covering material. However, in general, the diameter of the wire in the wire drawing step must be reduced by 1/10 or more.

再者，因為形成本發明之金(Au)微粒子以無數點狀存在之態樣的表皮層極薄，故一旦形成表皮層，則表皮層不會因為一般的拉線速度及縮徑率而被破壞。因此，若適當調整調質熱處理的溫度與時間，則可輕易形成既定理論厚度的金(Au)微粒子以無數點狀存在的態樣。 Further, since the surface layer in which the gold (Au) fine particles of the present invention are present in an innumerable dot shape is extremely thin, once the skin layer is formed, the skin layer is not damaged by the general wire drawing speed and the reduction ratio. damage. Therefore, if the temperature and time of the tempering heat treatment are appropriately adjusted, it is possible to easily form a state in which gold (Au) fine particles of a predetermined theoretical thickness exist in a myriad of dots.

芯材的銅合金，若包含預期的添加元素，則為一般純度99.9質量%以上的銅(Cu)所構成的銅合金。純度99.9質量%以上的銅(Cu)所構成的銅合金的情況中，選擇磷(P)或金(Au)的情況下，可參照習知先前技術的合金，適當決定其他剩下的金屬成分。銅合金母材的純度，較佳為純度99.99質量%以上的銅(Cu)所構成的銅合金，特佳為純度99.999質量%以上的銅(Cu)所構成的銅合金。接著，亦可因應所需之半導體種類及用途，而決定適當添加元素的種類，亦可因應作為接合線所需的熱性質、機械性質，適當決定添加元素的組合及添加量。 The copper alloy of the core material is a copper alloy composed of copper (Cu) having a general purity of 99.9% by mass or more, if it contains a desired additive element. In the case of a copper alloy composed of copper (Cu) having a purity of 99.9% by mass or more, when phosphorus (P) or gold (Au) is selected, other remaining metal components can be appropriately determined by referring to an alloy of the prior art. . The purity of the copper alloy base material is preferably a copper alloy composed of copper (Cu) having a purity of 99.99% by mass or more, and particularly preferably a copper alloy composed of copper (Cu) having a purity of 99.999 mass% or more. Then, depending on the type and application of the semiconductor to be used, the type of the element to be added may be determined, and the combination and addition amount of the additive element may be appropriately determined depending on the thermal properties and mechanical properties required for the bonding wire.

若於芯材的銅(Cu)中存在磷(P)，則可形成穩定的FAB，此已為人所知(日本特開2010-225722號公報及國際公開WO2011/129256號公報)。因此，該銅合金包含磷(P)的情況中，較佳為含有3質量ppm以上500質 量ppm以下。 When phosphorus (P) is present in the copper (Cu) of the core material, a stable FAB can be formed, which is known (Japanese Laid-Open Patent Publication No. 2010-225722 and International Publication No. WO2011/129256). Therefore, in the case where the copper alloy contains phosphorus (P), it is preferable to contain 3 mass ppm or more and 500 masses. The amount is below ppm.

再者，若芯材的銅(Cu)中存在金(Au)，則以無數點狀存在最表面的金(Au)微粒子容易混入熔融焊球的內部，最表面的金(Au)微粒子，相較於分散於鈀(Pd)被覆層中，其優先分散於芯材的銅(Cu)中。結果，芯材的銅(Cu)之中存在金(Au)者，相較於未存在者，具有妨礙AuCu的金屬間化合物形成於與鋁墊之接合界面這樣相對的效果。另一方面，因為金(Au)為高價金屬，故無法大量添加。因此，該銅合金包含金(Au)的情況下，較佳係包含50質量ppm以上500質量ppm以下。 In addition, when gold (Au) is present in the copper (Cu) of the core material, the gold (Au) fine particles having the outermost surface are easily mixed into the inside of the molten solder ball, and the gold (Au) fine particles on the outermost surface are phased. It is preferentially dispersed in copper (Cu) of the core material than in the palladium (Pd) coating layer. As a result, in the case where gold (Au) is present in the copper (Cu) of the core material, there is an effect that the intermetallic compound which hinders AuCu is formed on the joint interface with the aluminum pad as compared with the non-existent one. On the other hand, since gold (Au) is a high-priced metal, it cannot be added in a large amount. Therefore, when the copper alloy contains gold (Au), it is preferably contained in an amount of 50 ppm by mass or more and 500 ppm by mass or less.

再者，本發明中的線材表面的極薄表面層及被覆層，皆在第一接合的FAB接合時消失，再者，在第二接合的超音波接合時，亦在接合處消失。 Further, in the present invention, the extremely thin surface layer and the coating layer on the surface of the wire disappeared at the time of joining of the first joined FAB, and also disappeared at the joint at the time of ultrasonic bonding of the second joining.

根據本發明的球焊用金(Au)分散銅線，因為在電弧炬與接合線的前端之間，以無數點狀存在於接合線的最表面的金(Au)微粒子形成如避雷針一般的電弧放電，故在第一接合時的電弧放電穩定。再者，因為該最表面極薄，因此不會有形成的熔融焊球浸潤根部未熔融之線材而導致焊球偏移的問題。結果，相較於目前的尺寸，可將球焊用金(Au)分散銅線更加細微化。 The gold (Au) dispersion copper wire for ball bonding according to the present invention, because between the arc torch and the front end of the bonding wire, gold (Au) fine particles existing in the outermost surface of the bonding wire in an infinite number of points form an arc such as a lightning rod. The discharge is stable, so the arc discharge at the first junction is stable. Further, since the outermost surface is extremely thin, there is no problem that the formed molten solder balls infiltrate the unmelted wires of the root portion and cause the solder balls to shift. As a result, the gold (Au) dispersed copper wire for ball bonding can be made finer than the current size.

再者，可縮小鋁墊面積，而且直徑較小的焊球可以高密度地配置金(Au)分散銅線。再者，根據本發明的金(Au)分散銅線，鈀(Pd)被覆層及金(Au)表皮層可阻斷從線材表面侵入的氧，故可得到芯材的銅合金不會氧化的效果。再者，本發明的球焊用金(Au)分散銅線，因為被覆層極薄，故與 被覆材料的材質無關，可得到穩定的正球形焊球，亦可良好地形成電路等。 Further, the area of the aluminum pad can be reduced, and the solder ball having a smaller diameter can be disposed with a high density of gold (Au) dispersed copper wire. Further, according to the gold (Au) dispersion copper wire of the present invention, the palladium (Pd) coating layer and the gold (Au) skin layer can block oxygen intruding from the surface of the wire, so that the copper alloy of the core material can be prevented from being oxidized. effect. Furthermore, the gold (Au) dispersion copper wire for ball bonding of the present invention is extremely thin because of the extremely thin coating layer. Regardless of the material of the covering material, a stable positive spherical solder ball can be obtained, and a circuit or the like can be formed favorably.

更進一步，本發明的球焊用金(Au)分散銅線，因為金(Au)微粒子以無數點狀存在線材最表面，故即使將線材彼此多層捲繞，線材彼此亦不會黏附。結果，線材的解繞性變得良好。再者，作為附加效果，線材表面相對於焊針的平滑性變好。再者，根據本發明的球焊用金(Au)分散銅線，線材最表面的金(Au)微粒子不會從鈀(Pd)的被覆層剝離。因此，即使重複接合多次，銅(Cu)的氧化物亦不會附著於焊針，故不會污染焊針。 Further, in the gold (Au) dispersion copper wire for ball bonding of the present invention, since the gold (Au) fine particles are present in the outermost surface of the wire in a myriad of dots, the wires do not adhere to each other even if the wires are multi-layered. As a result, the unwinding property of the wire becomes good. Further, as an additional effect, the smoothness of the surface of the wire with respect to the welding pin becomes better. Further, according to the gold (Au) dispersion copper wire for ball bonding of the present invention, the gold (Au) fine particles on the outermost surface of the wire are not peeled off from the coating layer of palladium (Pd). Therefore, even if the bonding is repeated a plurality of times, the oxide of copper (Cu) does not adhere to the soldering pin, so that the soldering pin is not contaminated.

第一圖係顯示接合線之電弧放電的示意圖。 The first figure shows a schematic diagram of the arc discharge of the bond wires.

第二圖係本發明之接合線表面中的金(Au)的分布影像。 The second figure is a distribution image of gold (Au) in the surface of the bonding wire of the present invention.

第三圖係本發明之接合線表面中的鈀(Pd)的分布影像。 The third figure is a distribution image of palladium (Pd) in the surface of the bonding wire of the present invention.

【實施例】 [Examples]

芯材係使用在純度99.999質量%以上的銅(Cu)中添加100質量ppm的磷(P)的材料，或未添加的材料，對其進行連續鑄造，並於中間熱處理(600℃×1小時)後進行壓延，之後進行拉線，而得到以被覆材被覆前的粗線(直徑1.0mm)。 The core material is a material in which 100 mass ppm of phosphorus (P) is added to copper (Cu) having a purity of 99.999 mass% or more, or a material which is not added, which is continuously cast and heat-treated at an intermediate temperature (600 ° C × 1 hour). After that, rolling was performed, and then the wire was pulled to obtain a thick line (diameter: 1.0 mm) before being coated with the covering material.

此處，表1所示的表皮層的金的值，係以王水溶解1萬公尺左右的線徑17μm的線材，並以高頻感應耦合電漿發光分光分析法(島津製作所股份有限公司的ICPS-8100)求得該溶液中的金(Au)與鈀(Pd)的濃度，再從該濃度算出其在接合線之線徑中的均勻膜厚。亦即，其係以ICP的化學分析所 得到的換算值。 Here, the gold value of the skin layer shown in Table 1 is a wire having a wire diameter of 17 μm dissolved in aqua regia of about 10,000 m, and is subjected to high-frequency inductively coupled plasma luminescence spectrometry (Shimadzu Corporation) The concentration of gold (Au) and palladium (Pd) in the solution was determined by ICPS-8100), and the uniform film thickness in the wire diameter of the bonding wire was calculated from the concentration. That is, it is based on the chemical analysis of ICP. The converted value obtained.

接著，準備表1所示的鈀(Pd)的被覆層以及金(Au)的表皮層，並將其被覆於該粗線的外周。表皮層的金(Au)的純度為99.9質量%以上，鈀(Pd)的純度為99質量%以上。之後，藉由鑽石拉線模以濕式法進行連續拉線，再進行480℃×1秒的調質熱處理，最後得到直徑17μm的球焊用金(Au)分散銅線。將該等例子作為實施例1~20。再者，平均的縮徑率為6~20%，最終線速為100~1000m/分。再者，芯材的銅(Cu)在被覆前以200~600℃進行1次0.01~120分鐘的熱處理。 Next, a coating layer of palladium (Pd) and a skin layer of gold (Au) shown in Table 1 were prepared and covered on the outer circumference of the thick line. The purity of gold (Au) in the skin layer is 99.9% by mass or more, and the purity of palladium (Pd) is 99% by mass or more. Thereafter, the wire was continuously drawn by a wet method using a diamond drawing die, and then subjected to a tempering heat treatment at 480 ° C for 1 second, and finally a gold (Au) dispersion copper wire for ball bonding having a diameter of 17 μm was obtained. These examples are taken as Examples 1 to 20. Furthermore, the average reduction ratio is 6 to 20%, and the final line speed is 100 to 1000 m/min. Further, the copper (Cu) of the core material is heat-treated at 200 to 600 ° C for 0.01 to 120 minutes before coating.

(FAB穩定性試驗) (FAB stability test)

以下述方法進行FAB穩定性試驗。 The FAB stability test was carried out in the following manner.

亦即，如表1右欄所示的例中，針對實施例1~實施例20的線材，透過K&S公司製全自動焊線機IConnProCu，在鍍Ag的引線架(QFP-200)上，藉由30μm的熔融焊球，以使壓接徑成為40μm，電流值為45mA，電弧放電時間為347微秒，對1,000條線材以FAB進行第一球焊。該結果顯示於表1右欄。此處，○記號係表示「未因電弧放電導致焊球偏離芯軸」者，×記號則表示「1條以上的線材發生焊球偏離芯軸之情況」者。從該試驗結果可得知，本發明的球焊用金(Au)分散銅線，不會因為電弧放電而發生熔融焊球的不均勻。 That is, in the example shown in the right column of Table 1, the wires of Examples 1 to 20 were passed through the Agon ProCu manufactured by K&S Co., Ltd. on the Ag-plated lead frame (QFP-200). From the 30 μm molten solder ball, the crimping diameter was 40 μm, the current value was 45 mA, the arc discharge time was 347 μsec, and the first ball bonding was performed on 1,000 wires with FAB. The results are shown in the right column of Table 1. Here, the ○ symbol indicates that "the solder ball is not deviated from the mandrel due to the arc discharge", and the X mark indicates that "the one or more wires are out of the mandrel." As is apparent from the results of the test, the gold (Au) dispersion copper wire for ball bonding of the present invention does not cause unevenness of the molten solder balls due to arc discharge.

(FAB偏移試驗) (FAB offset test)

FAB偏移試驗，與上述的FAB穩定性試驗相同，透過全自動焊線機IConnProCu，使電流值為45mA，使電弧放電時間為347微秒，對1,000條線材以FAB進行第一球焊。該結果顯示於表1右欄。此處，○記號為完全 未因熔融焊球的爬升而導致焊球偏離芯軸的情況，×記號表示一條以上的線材發生匍匐焊球的情況。從該試驗結果可得知，本發明的球焊用金(Au)分散銅線不會發生匍匐焊球。 The FAB offset test, like the FAB stability test described above, was performed by a fully automatic wire bonding machine IConnProCu with a current value of 45 mA, an arc discharge time of 347 microseconds, and a first ball bonding of 1,000 wires to FAB. The results are shown in the right column of Table 1. Here, the ○ mark is complete The fact that the solder ball does not deviate from the mandrel due to the climbing of the molten solder ball, the X mark indicates that one or more wires are subjected to the solder ball. As is apparent from the results of the test, the gold (Au) dispersed copper wire for ball bonding of the present invention does not cause a solder ball.

因此可得知，本發明的實施例1~實施例20的線材，其熔融焊球的形狀極為穩定，而可縮小鋁墊的面積。另外可得知，本發明的球焊用金(Au)分散銅線(實施例1~實施例20)，即使反覆接合超過1萬公尺，皆沒有焊針堵塞的情況，焊針的平滑性良好。再者，亦未觀察到焊針內面的磨耗。再者，本發明的任一球焊用金(Au)分散銅線(實施例1~實施例20)，在線材的解繞試驗中皆為良好。 Therefore, it can be seen that the wire rods of Examples 1 to 20 of the present invention have extremely stable molten solder balls and can reduce the area of the aluminum pad. Further, it can be seen that the gold (Au) dispersion copper wire for ball bonding of the present invention (Examples 1 to 20) has no solder pin clogging even when the bonding is over 10,000 meters, and the smoothness of the welding pin is obtained. good. Furthermore, the wear of the inner surface of the welding pin was not observed. Further, any of the gold (Au) dispersion copper wires for ball bonding of the present invention (Examples 1 to 20) was excellent in the unwinding test of the wire.

【習知例】 [Practical example]

將僅形成鈀(Pd)被覆層200奈米(nm)的接合線作為習知例1；將形成鈀(Pd)被覆層500奈米(nm)、金(Au)的表皮層200奈米(nm)的接合線作為習知例2。以與實施例相同的方式，將該等習知例1與2的線材進行FAB穩定性試驗及FAB偏移試驗，得到表1右欄的結果。從該結果可明確得知，習知例1的線材在FAB穩定性試驗中表現不佳，習知例2的線材無法滿足FAB偏移試驗。 A bonding wire of only 200 nm (nm) of a palladium (Pd) coating layer was formed as a conventional example 1; a palladium (Pd) coating layer of 500 nm (nm) and a gold (Au) skin layer of 200 nm were formed ( The bonding line of nm is taken as the conventional example 2. The wires of the conventional examples 1 and 2 were subjected to FAB stability test and FAB shift test in the same manner as in the examples to obtain the results in the right column of Table 1. From the results, it is clear that the wire of the conventional example 1 did not perform well in the FAB stability test, and the wire of the conventional example 2 could not satisfy the FAB offset test.

【比較例】 [Comparative example]

將形成鈀(Pd)被覆層100奈米(nm)、形成金(Au)理論膜厚為10奈米(nm)及0.1奈米(nm)的接合線作為比較例1及2。以與實施例相同的方式，對該等比較例1與2的線材進行FAB穩定性試驗及FAB偏移試驗，得到表1右欄的結果。從該結果可明確得知，比較例1的線材，與習知例2相同，於FAB穩定性試驗中表現不佳，比較例2的線材，與習知例1相同，無法滿足FAB 偏移試驗。 Bonding lines in which a palladium (Pd) coating layer of 100 nm (nm) and a gold (Au) theoretical film thickness of 10 nm (nm) and 0.1 nm (nm) were formed were used as Comparative Examples 1 and 2. The wires of Comparative Examples 1 and 2 were subjected to FAB stability test and FAB shift test in the same manner as in the examples, and the results in the right column of Table 1 were obtained. As is clear from the results, the wire of Comparative Example 1 was inferior in the FAB stability test as in the conventional example 2, and the wire of Comparative Example 2 was the same as the conventional example 1 and could not satisfy the FAB. Offset test.

(HAST試驗) (HAST test)

再者，在進行HAST試驗(130℃×85RH(相對濕度))試驗時，雖省略測定結果，但相較於習知例1、2及比較例1、2，實施例1~實施例20的壽命皆更長，且可靠度高。 In addition, when the HAST test (130 ° C × 85 RH (relative humidity)) test was performed, the measurement results were omitted, but compared with the conventional examples 1, 2 and the comparative examples 1 and 2, the examples 1 to 20 were compared. Longer life and high reliability.

【產業上的可利用性】 [Industrial availability]

本發明的球焊用金(Au)分散銅線，取代以往的金合金線材，除了通用IC、離散式積體電路(discrete IC)、記憶體IC以外，亦可用於高溫高濕之用途且要求低成本的LED用的IC封裝、車載半導體用IC封裝等的半導體用途。 The gold (Au) dispersion copper wire for ball bonding of the present invention can be used for high-temperature and high-humidity applications in addition to general-purpose ICs, discrete ICs, and memory ICs in place of conventional gold alloy wires. Semiconductor applications such as IC packages for low-cost LEDs and IC packages for automotive semiconductors.

Claims (6)

一種球焊用金(Au)分散銅線，其特徵為：在銅(Cu)純度99.9質量%以上的銅合金所構成的芯材上形成鈀(Pd)被覆層及金(Au)表皮層、且線徑為10~25μm的球焊用鈀(Pd)被覆銅線，其中該金(Au)藉由化學分析的理論膜厚為0.1奈米(nm)以上10奈米(nm)以下；藉由電子微探儀(EPMA)的表面分析所得到的金(Au)的分布，係該金(Au)微粒子以無數點狀分布於該鈀(Pd)被覆層上。 A gold (Au) dispersion copper wire for ball bonding, characterized in that a palladium (Pd) coating layer and a gold (Au) skin layer are formed on a core material composed of a copper alloy having a copper (Cu) purity of 99.9% by mass or more. And a palladium (Pd) coated copper wire having a wire diameter of 10 to 25 μm, wherein the theoretical thickness of the gold (Au) by chemical analysis is 0.1 nm or more and 10 nm or less; The distribution of gold (Au) obtained by surface analysis of an electronic micro-probe (EPMA) is such that the gold (Au) fine particles are distributed in a random number on the palladium (Pd) coating layer. 如申請專利範圍第1項之球焊用金(Au)分散銅線，其中該銅合金含有3質量ppm以上500質量ppm以下的磷(P)。 A gold (Au) dispersion copper wire for ball bonding according to the first aspect of the invention, wherein the copper alloy contains phosphorus (P) in an amount of 3 ppm by mass or more and 500 ppm by mass or less. 如申請專利範圍第1項之球焊用金(Au)分散銅線，其中該銅合金含有50質量ppm以上500質量ppm以下的金(Au)。 A gold (Au) dispersion copper wire for ball bonding according to the first aspect of the invention, wherein the copper alloy contains 50 mass ppm or more and 500 mass ppm or less of gold (Au). 如申請專利範圍第1項之球焊用金(Au)分散銅線，其中該銅合金含有0.2質量ppm以上、100質量ppm以下的磷(P)及金(Au)以外的金屬元素。 The gold (Au) dispersion copper wire for ball bonding according to the first aspect of the invention, wherein the copper alloy contains 0.2 ppm by mass or more and 100 ppm by mass or less of a metal element other than phosphorus (P) and gold (Au). 如申請專利範圍第1項之球焊用金(Au)分散銅線，其中該銅合金中含有3質量ppm以上500質量ppm以下的磷(P)、50質量ppm以上500質量ppm以下的金(Au)、0.2質量ppm以上100質量ppm以下的其他金屬元素，且該等元素的總量小於1,000ppm。 The gold (Au) dispersion copper wire for ball bonding according to the first aspect of the invention, wherein the copper alloy contains 3 ppm by mass or more and 500 ppm by mass or less of phosphorus (P), and 50 ppm by mass or more and 500 ppm by mass or less of gold ( Au), 0.2 mass ppm or more and 100 mass ppm or less of other metal elements, and the total amount of these elements is less than 1,000 ppm. 如申請專利範圍第1項之球焊用金(Au)分散銅線，其中該理論膜厚為2奈米(nm)以下。 The gold (Au) dispersion copper wire for ball bonding according to the first aspect of the patent application, wherein the theoretical film thickness is 2 nm or less.
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