JP3116332B2 - Nickel-plated copper alloy lead frame for solder die bonding - Google Patents
Nickel-plated copper alloy lead frame for solder die bondingInfo
- Publication number
- JP3116332B2 JP3116332B2 JP34868495A JP34868495A JP3116332B2 JP 3116332 B2 JP3116332 B2 JP 3116332B2 JP 34868495 A JP34868495 A JP 34868495A JP 34868495 A JP34868495 A JP 34868495A JP 3116332 B2 JP3116332 B2 JP 3116332B2
- Authority
- JP
- Japan
- Prior art keywords
- solder
- nickel
- lead frame
- copper alloy
- plating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Landscapes
- Lead Frames For Integrated Circuits (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は、銀めっきを施さな
い状態で、ニッケルめっきに半導体チップが直接はんだ
ダイボンディングされるニッケルめっき銅合金リードフ
レームに関し、特に、酸素濃度の高い還元雰囲気中にお
いて鉛を含まないはんだを用いた状態でも、良好なはん
だダイボンディング性を持ち、かつワイヤボンディング
性に優れるニッケルめっき銅合金リードフレームに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nickel-plated copper alloy lead frame in which a semiconductor chip is directly solder-die-bonded to nickel plating in a state where silver plating is not performed. The present invention relates to a nickel-plated copper alloy lead frame having good solder die bonding property and excellent wire bonding property even in a state using solder containing no.
【0002】[0002]
【従来の技術】従来、銅合金リードフレームのはんだダ
イボンディングされる表面には、良好なはんだ拡がりを
得るために銀めっきが施されていた。そして、半導体組
立工程は、はんだダイボンディング時の熱によるリード
フレームの酸化を防止するため、窒素ガスや水素を含む
還元雰囲気中で行われているが、銀めっきは酸化しにく
く、後述するように雰囲気中の酸素濃度が400ppm
以上に高くなっていても良好なはんだ拡がりが得られる
ため、銀めっき銅合金リードフレームに関して、半導体
組立雰囲気中の酸素濃度が問題とされたことはなく、ま
た、酸素濃度について十分検討が加えられたこともな
い。2. Description of the Related Art Conventionally, a surface of a copper alloy lead frame to be solder-die bonded has been subjected to silver plating in order to obtain good solder spread. The semiconductor assembling process is performed in a reducing atmosphere containing nitrogen gas or hydrogen in order to prevent oxidation of the lead frame due to heat at the time of solder die bonding. Oxygen concentration in atmosphere is 400ppm
Good solder spread can be obtained even if the height is higher than above.Therefore, regarding silver-plated copper alloy lead frames, the oxygen concentration in the semiconductor assembly atmosphere has never been a problem, and the oxygen concentration has been sufficiently studied. Never.
【0003】一方、生産性向上、コストダウンの観点よ
り銀めっきを省略し、ニッケルめっきに直接はんだダイ
ボンディングをすることが考えられた。以下、この技術
に関し、従来技術とその問題点につき簡単に触れる。ま
ず、ニッケルめっきに直接はんだダイボンディングをす
る場合、良好なはんだ拡がりを得るためには、還元雰囲
気中の酸素濃度を銀めっきにはんだ付けする場合に比べ
低く(例えば100ppm以下)制御する必要があり、
これがコストアップ要因となっていた。On the other hand, it has been considered that silver plating is omitted and solder die bonding is performed directly on nickel plating from the viewpoint of improving productivity and reducing costs. In the following, this technology is briefly described with respect to the conventional technology and its problems. First, in the case of performing direct solder die bonding on nickel plating, it is necessary to control the oxygen concentration in the reducing atmosphere to be lower (for example, 100 ppm or less) than in the case of soldering on silver plating in order to obtain good solder spread. ,
This was a factor of cost increase.
【0004】銀めっきを省略しニッケルめっきに直接ダ
イボンディングする技術として、例えば特開昭62−2
91951号公報には、P(リン)やB(ボロン)を含
有する耐酸化性ニッケルめっきを施した銅合金リードフ
レームが示されている。しかし、PやBを含有すると、
ニッケルめっきが硬くなって加工性が低下し、めっき後
の打ち抜き加工が難しくなるため、リードフレーム形状
に加工した後めっきを施す必要があり、生産性が悪かっ
た。また、最近、電気部品の高密度集積化によりリード
フレームが受ける熱量は増加しており、耐熱性に優れる
ニッケルめっき銅合金リードフレームが望まれている
が、PやBを含有するニッケルめっきは、はんだ付け後
に長時間加熱すると、はんだ剥離を発生するという問題
があった。[0004] As a technique for directly bonding to nickel plating by omitting silver plating, for example, Japanese Patent Application Laid-Open No. Sho 62-2
Japanese Patent No. 91951 discloses a copper alloy lead frame that has been subjected to oxidation-resistant nickel plating containing P (phosphorus) or B (boron). However, if P or B is contained,
Nickel plating is hardened and workability is reduced, and punching after plating becomes difficult. Therefore, plating must be performed after processing into a lead frame shape, and productivity is poor. Also, recently, the amount of heat received by the lead frame has been increasing due to the high-density integration of electric components, and a nickel-plated copper alloy lead frame having excellent heat resistance has been desired. When heated for a long time after soldering, there is a problem that solder peeling occurs.
【0005】また、はんだダイボンディングに用いられ
るはんだとしては、これまで鉛含有量が高いはんだ(P
b−5%Sn、Pb−5%Sn−1.5%Ag等)が用
いられている。この種のはんだは溶融温度が高くコスト
が安いという利点はあるが、最近鉛による環境汚染を防
止し、あるいは組立工程の低温度化指向に対応して、鉛
を含まない錫系はんだ(Sn−9%Zn、Sn−5%S
b、Sn−5%Sb−0.5Ni、Sn−8%Bi等)
の使用が増えつつある。しかし、鉛含有はんだと鉛を含
まない錫系はんだでは、溶融温度が異なるだけでなく合
金層の成長速度、拡散状態が異なり、従来の鉛含有はん
だ(Pb−Sn共晶系はんだ含む)を用いた評価方法で
選ばれたこれまでのニッケルめっきに対しては、鉛を含
まない錫系はんだのはんだ拡がりが悪かった。As a solder used for solder die bonding, a solder having a high lead content (P
b-5% Sn, Pb-5% Sn-1.5% Ag, etc.). This type of solder has the advantage that the melting temperature is high and the cost is low, but recently, in order to prevent environmental pollution due to lead or to reduce the temperature of the assembly process, a tin-based solder (Sn- 9% Zn, Sn-5% S
b, Sn-5% Sb-0.5Ni, Sn-8% Bi, etc.)
The use of is increasing. However, a lead-containing solder and a tin-based solder containing no lead not only have different melting temperatures, but also different growth rates and diffusion states of the alloy layer, so that conventional lead-containing solder (including Pb-Sn eutectic solder) is used. Compared with the conventional nickel plating selected by the evaluation method, the solder spread of the tin-based solder containing no lead was poor.
【0006】そして、最近半導体チップ、ペレットの大
型化が進んでいるが、大型のものを搭載するためにはは
んだ拡がり性がよく、撹拌などによりはんだ厚やはんだ
拡がりをコントロールできるリードフレームが必要とな
っている。Recently, semiconductor chips and pellets have been increasing in size. However, in order to mount a large-sized semiconductor chip and a pellet, it is necessary to provide a lead frame which has good solder spreadability and can control solder thickness and solder spread by stirring or the like. Has become.
【0007】[0007]
【発明が解決しようとする課題】本発明は、以上述べた
銀めっきを省略しニッケルめっきに直接ダイボンディン
グする技術の改良に関し、具体的には、コストダウンの
観点より、銀めっき付きリードフレームと同等の酸素濃
度の高い雰囲気(およそ400〜1000ppm)でも
はんだダイボンディングができ、生産性もよいニッケル
めっき銅合金リードフレームを得ること、及び、鉛を含
まない錫系はんだのはんだ拡がりがよく、はんだ厚やは
んだ拡がりのコントロールが可能で、はんだダイボンデ
ィング性に優れるニッケルめっき銅合金リードフレーム
を得ることを目的とする。SUMMARY OF THE INVENTION The present invention relates to an improvement of the technique of directly die-bonding to nickel plating by omitting the above-mentioned silver plating. More specifically, from the viewpoint of cost reduction, the present invention relates to a lead frame with silver plating. Solder die bonding can be performed even in an atmosphere having an equivalent high oxygen concentration (approximately 400 to 1000 ppm), and a nickel-plated copper alloy lead frame with good productivity can be obtained. It is an object of the present invention to obtain a nickel-plated copper alloy lead frame capable of controlling the thickness and the spread of solder and having excellent solder die bonding properties.
【0008】[0008]
【課題を解決するための手段】ニッケルめっき銅合金リ
ードフレームは、先に挙げた特開昭62−291951
号公報のようにニッケルの酸化を少なくしたリードフレ
ームであっても、銀めっき付きリードフレーム用半導体
組立ラインにおいては、ニッケルめっき表面でのはんだ
拡がりが銀めっきより劣るという問題がある。ニッケル
が銀よりはんだ拡がりが悪いのは一般に当然と考えられ
ていたが、本発明者が上記ラインにおいてはんだ拡がり
が低下する原因を鋭意検討した結果、半導体組立ライン
雰囲気中に含まれる酸素濃度が高い時に、はんだ拡がり
が低下することを確認した。A nickel-plated copper alloy lead frame is disclosed in Japanese Patent Application Laid-Open No. 62-291951.
Even in a lead frame in which oxidation of nickel is reduced as in the publication, there is a problem that the spread of solder on the surface of nickel plating is inferior to that of silver plating in a semiconductor assembly line for lead frames with silver plating. It was generally considered that nickel has a poorer solder spread than silver, but as a result of the present inventor's intensive study of the cause of the reduced solder spread in the above line, the oxygen concentration contained in the semiconductor assembly line atmosphere was high. At times, it was confirmed that the solder spread was reduced.
【0009】すなわち、銀めっき付きリードフレーム用
半導体組立ライン中の雰囲気は、リードフレーム切断面
の銅やはんだボールの酸化を防ぐため、水素を5〜20
%含む窒素ガス(還元雰囲気)が用いられているが、本
発明者の調査によれば、この窒素ガス雰囲気中には大気
の巻き込みにより400〜1000ppm程度の酸素が
含まれる。そして、通常の光沢ワット浴より得られたニ
ッケルめっき銅合金リードフレームでは、還元雰囲気中
の酸素濃度が300ppm以下では良好なはんだ拡がり
を示すが、酸素濃度が300ppmを越えるとはんだ拡
がりが低下し始め、500ppmではほとんどはんだが
拡がらない。That is, the atmosphere in the semiconductor assembly line for a lead frame with silver plating is 5-20 hydrogen in order to prevent oxidation of copper and solder balls on the cut surface of the lead frame.
% Nitrogen gas (reducing atmosphere) is used. According to the investigation by the present inventors, this nitrogen gas atmosphere contains about 400 to 1000 ppm of oxygen due to entrainment of the air. And, in the nickel-plated copper alloy lead frame obtained from a normal bright watt bath, good solder spread is exhibited when the oxygen concentration in the reducing atmosphere is 300 ppm or less, but when the oxygen concentration exceeds 300 ppm, the solder spread begins to decrease. At 500 ppm, the solder hardly spreads.
【0010】一方、10%程度水素を含む還元雰囲気中
では、1000ppm程度の酸素を含有していても、ニ
ッケルの酸化が少ないことが確認され、はんだ拡がり低
下の原因がニッケル自体にあるのではないことが分っ
た。そして、本発明者がさらに検討を重ねた結果、ニッ
ケルめっき表面でのはんだ拡がり低下の原因は、ニッケ
ルめっき皮膜中に含まれる微量不純物の影響であること
を突き止めた。この微量不純物は、ニッケルめっき浴に
添加される光沢剤や均一電着剤、応力緩和剤などの成分
がニッケルめっき皮膜中の取り込まれるものであり、還
元雰囲気中でも酸素濃度が高い場合に、はんだ拡がりを
低下させる作用をなす。On the other hand, in a reducing atmosphere containing about 10% hydrogen, it was confirmed that even if oxygen was contained at about 1000 ppm, oxidation of nickel was small, and the cause of the decrease in solder spread was not due to nickel itself. I understood that. As a result of further studies by the present inventor, they have found that the cause of the decrease in solder spread on the nickel plating surface is the effect of trace impurities contained in the nickel plating film. These trace impurities are components that are added to the nickel plating bath, such as brighteners, throwing agents, and stress relaxation agents, and are incorporated into the nickel plating film. When the oxygen concentration is high even in a reducing atmosphere, the solder spreads. Acts to lower the
【0011】本発明は上記知見に基づいてなされたもの
であり、ニッケルめっきの鏡面反射率が25%以上であ
り、表面から0.1μm以内のニッケル中の硫黄含有量
が0.0005wt%以下であることを特徴とするはん
だダイボンディング用ニッケルめっき銅合金リードフレ
ームである。この銅合金リードフレームにおいては、最
表面のニッケルめっきが0.5〜10.0wt%のコバ
ルト又はパラジウムの一方又は双方を含有することでは
んだ拡がりが一層良好となる。The present invention has been made on the basis of the above-mentioned findings, and has a specular reflectance of nickel plating of 25% or more and a sulfur content of nickel within 0.1 μm from the surface of 0.0005 wt% or less. A nickel-plated copper alloy lead frame for solder die bonding. In this copper alloy lead frame, the nickel plating on the outermost surface contains 0.5 to 10.0 wt% of one or both of cobalt and palladium, so that the solder spread is further improved.
【0012】本発明において、ニッケル表面から深さ方
向へ0.1μm以内のニッケル層の硫黄含有量を0.0
005wt%以下としたのは、はんだと合金層を形成
し、はんだ拡がりに影響を及ぼす表面から深さ0.1μ
m以内の部分において、光沢剤などよりニッケル層に取
り込まれる硫黄元素が0.0005wt%を越えると、
酸素濃度が高い雰囲気ではんだをはじき、はんだ拡がり
が低下するためである。この部分において硫黄の含有量
を0.0005wt%以下とすることにより、鉛レスは
んだ(鉛を含まないはんだ)とニッケル表面の接触角が
小さくなり、はんだ拡がりが良好となって、優れたはん
だダイボンディング性を示す。In the present invention, the sulfur content of the nickel layer within 0.1 μm in the depth direction from the nickel surface is set to 0.0
The reason why the content is set to 005 wt% or less is that a depth of 0.1 μm is formed from a surface which forms an alloy layer with solder and affects solder spread.
m, the sulfur element taken into the nickel layer from the brightener or the like exceeds 0.0005 wt%,
This is because the solder is repelled in an atmosphere having a high oxygen concentration, and the spread of the solder is reduced. By reducing the sulfur content to 0.0005 wt% or less in this portion, the contact angle between the lead-less solder (solder containing no lead) and the nickel surface is reduced, the solder spread is improved, and an excellent solder die is obtained. Shows bonding properties.
【0013】また、本発明において、ニッケルめっきの
鏡面反射率を25%以上としたのは、ワイヤボンディン
グ性、樹脂バリ除去性、はんだ拡がりのコントロールを
良好にするためである。すなわち、ワイヤボンディング
は金やアルミニウム、銅などの合金線を用い、超音波を
使ってチップとリードを接合するものであるが、接合信
頼性はリードフレーム表面が平滑なほど良好であり、ま
た、リードフレーム表面が平滑なほうが、はんだダイボ
ンディング時のはんだ棒によるはんだ拡がりのコントロ
ールも行いやすい。なお、リードフレーム表面の平滑さ
は鏡面反射率と相関関係があり、本発明では平滑さを鏡
面反射率で表している。Further, in the present invention, the specular reflectance of the nickel plating is set to 25% or more in order to improve the wire bonding property, the resin burr removing property, and the control of the solder spread. In other words, wire bonding uses an alloy wire such as gold, aluminum, or copper to bond the chip and the lead using ultrasonic waves. However, the bonding reliability is better as the lead frame surface is smoother. The smoother the lead frame surface, the easier it is to control the spread of the solder by the solder bar during solder die bonding. Note that the smoothness of the lead frame surface has a correlation with the specular reflectance, and in the present invention, the smoothness is represented by the specular reflectance.
【0014】本発明において、最表面のニッケルめっき
が0.5〜10.0wt%のコバルト又はパラジウムの
一方又は双方を含有するとき、還元雰囲気中の酸素濃度
が高い場合でもはんだ拡がりがさらに良好になる。ここ
で、ニッケルめっき皮膜中のコバルト及び/又はパラジ
ウム含有量を合計で0.5〜10.0wt%としたの
は、0.5wt%以下では添加の効果が少なく、10.
0wt%を越えるとニッケルめっき皮膜の加工性が低下
するとともに、はんだ付け後に長時間加熱するとはんだ
密着性が低下するためである。In the present invention, when the nickel plating on the outermost surface contains 0.5 to 10.0 wt% of one or both of cobalt and palladium, even if the oxygen concentration in the reducing atmosphere is high, the solder spread is further improved. Become. Here, the reason why the total content of cobalt and / or palladium in the nickel plating film is set to 0.5 to 10.0 wt% is that the effect of addition is small at 0.5 wt% or less.
If the content exceeds 0 wt%, the workability of the nickel plating film is reduced, and if heated for a long time after soldering, the solder adhesion is reduced.
【0015】このように、本発明では、ニッケル表面の
硫黄含有量を制限するとともに鏡面反射率を規定するこ
とにより、酸素濃度の高い雰囲気でも銀めっきと同等の
良好なはんだ拡がりとはんだ拡がりのコントロール性が
得られ、今後進展すると予想される鉛レスはんだによる
ダイボンディング性に優れたニッケルめっき銅合金リー
ドフレームを供給できる。As described above, according to the present invention, by limiting the sulfur content on the nickel surface and defining the specular reflectance, even in an atmosphere having a high oxygen concentration, the same good solder spread as in silver plating and the control of the solder spread can be achieved. It is possible to provide a nickel-plated copper alloy lead frame which is excellent in die bonding property by lead-less solder which is expected to develop in the future.
【0016】[0016]
【発明の実施の形態】銅合金リードフレームにおいて、
ニッケルめっきの厚みは銅の腐食と熱酸化、拡散を防止
するために0.5μm以上必要であり、通常2〜5μm
の厚さに施されている。一方、ニッケルめっき中の硫黄
含有量を0.0005wt%以下にするためには、光沢
剤や均一電着剤、応力緩和剤などを全く含まない無光沢
ニッケルめっきを施す方法があるが、無光沢ニッケルめ
っきを0.5μmを越えて施すと鏡面反射率が25%以
下になるという問題がある。従って、本発明に規定する
ように、表面から0.1μm以内のニッケル中の硫黄含
有量を0.0005wt%以下とするとともに、鏡面反
射率が25%以上とするためには、表層部のみ光沢剤等
を含まないニッケルめっき液を用いてめっきする方法
や、ニッケルめっき後の加熱により硫黄を最表面に濃縮
させた後、最表面のみを除去(エッチング等)する方法
等が考えられる。DESCRIPTION OF THE PREFERRED EMBODIMENTS In a copper alloy lead frame,
The thickness of the nickel plating is required to be 0.5 μm or more to prevent corrosion, thermal oxidation and diffusion of copper, and usually 2 to 5 μm.
It is applied to the thickness of. On the other hand, in order to reduce the sulfur content in the nickel plating to 0.0005 wt% or less, there is a method of applying a matte nickel plating that does not contain any brightener, a uniform electrodeposition agent, a stress relaxation agent, etc. If the nickel plating is applied to a thickness exceeding 0.5 μm, there is a problem that the specular reflectance becomes 25% or less. Therefore, as specified in the present invention, in order to reduce the sulfur content in nickel within 0.1 μm from the surface to 0.0005 wt% or less and to set the mirror reflectivity to 25% or more, only the surface layer portion should be glossy. A plating method using a nickel plating solution containing no agent or the like, a method in which sulfur is concentrated on the outermost surface by heating after nickel plating, and then only the outermost surface is removed (etching or the like) can be considered.
【0017】ニッケルめっきを2層に行う場合、下地は
銅の拡散を防止し、表面を平滑にするため光沢又は半光
沢のニッケルめっきを1〜5μm施すのが望ましい。こ
れが1μmより薄いとピンホールの存在などにより銅の
拡散を防止できない場合があり、5μmより厚くなると
生産性が低下するだけでなく、加工性が低下する。ま
た、曲げ加工が行われるリードフレームでは、加工性の
よい半光沢のニッケルめっきを2μm程度行うのが望ま
しい。一方、上層のめっきは光沢剤を含まないニッケル
めっきを0.1〜0.5μm施すのが望ましい。0.1
μmより薄いと下地の不純物の影響によるはんだ拡がり
の低下を防止できない。また、0.5μmを越えて厚く
めっきした場合には鏡面反射率が低下し始め、表面の平
滑さが低下(ワイヤボンディング性が低下)する。When nickel plating is performed on two layers, it is preferable to apply bright or semi-gloss nickel plating of 1 to 5 μm on the underlayer in order to prevent copper diffusion and smooth the surface. If the thickness is less than 1 μm, diffusion of copper may not be prevented due to the presence of pinholes. If the thickness is more than 5 μm, not only productivity is reduced but also processability is reduced. Further, in a lead frame subjected to bending, it is desirable to perform semi-bright nickel plating with good workability of about 2 μm. On the other hand, it is desirable that the upper layer be plated with nickel plating containing no brightener at 0.1 to 0.5 μm. 0.1
If the thickness is smaller than μm, it is impossible to prevent the spread of the solder from being reduced due to the influence of impurities in the base. If the thickness is more than 0.5 μm, the specular reflectance starts to decrease, and the smoothness of the surface decreases (the wire bonding property decreases).
【0018】なお、リードフレームの表面硬さはリード
部の加工性に影響を与え、ニッケルの酸化ははんだ拡が
りに影響を与える。そして、表面硬度及びニッケルの酸
化状態を測定することにより、ニッケルめっき製造時の
状態を管理することができる。例えば、ニッケルめっき
の浴やめっき条件が変化すると、不純物、光沢剤の取り
込み量が変化し、光沢剤が多くなるとニッケルの表面硬
度は高くなる。本発明においては、表面硬度はHv20
0〜450が望ましい。表面硬度がHv200より小さ
いとワイヤボンディング性が低下し、Hv450を越え
ると加工性が悪くなる。また、ニッケルの酸化はめっき
液の温度、乾燥条件や清浄度の影響を受け、温度が高く
なったり、めっきが汚れるとESCA分析によるニッケ
ル酸化物ピークとニッケル金属ピーク強度比(Nioxid
e/Nimetal)が高くなり、1.0を越えるとはんだ拡
がりが低下する。水素を含み酸素含有量が1000pp
m以下の還元雰囲気中ではんだダイボンディングする場
合、ニッケルの保管時の酸化はほとんど問題にはならな
いが、めっき直後のニッケルの酸化は少ない(Nioxid
e/Nimetal≦1.0)方が望ましい。The surface hardness of the lead frame affects the workability of the lead portion, and the oxidation of nickel affects the spread of the solder. Then, by measuring the surface hardness and the oxidation state of nickel, it is possible to manage the state at the time of nickel plating production. For example, if the nickel plating bath or plating conditions change, the amount of impurities and brighteners taken in changes, and the more brighteners, the higher the surface hardness of nickel. In the present invention, the surface hardness is Hv20.
0 to 450 is desirable. If the surface hardness is lower than Hv200, the wire bonding property is reduced, and if the surface hardness is higher than Hv450, the workability is deteriorated. The oxidation of nickel is affected by the temperature of the plating solution, drying conditions and cleanliness. If the temperature rises or the plating becomes dirty, the nickel oxide peak to nickel metal peak intensity ratio (Nioxid
e / Nimetal), and if it exceeds 1.0, the solder spread is reduced. Contains hydrogen and oxygen content is 1000pp
When solder die bonding is performed in a reducing atmosphere of less than m, oxidation of nickel during storage is hardly a problem, but oxidation of nickel immediately after plating is small (Nioxid
e / Nimetal ≦ 1.0) is desirable.
【0019】[0019]
【実施例】以下、本発明の実施例について説明する。 [実施例1]Fe:0.1wt%とP:0.03wt%
を含む高導電率の銅合金リードフレーム素材に、鏡面反
射率が35%のニッケルめっきを1.7μm施し、その
後、硫黄を含まないニッケルめっきを0.3μm施し
た。めっき後にスタンピング加工を施し、表1の実施例
1〜3に示す鏡面反射率及び硫黄含有量(表面から0.
1μm以下の硫黄含有量)をもつ銅合金リードフレーム
を得た。なお、硫黄を含まないニッケルめっき層は、実
施例1では無光沢ワット浴を用いて浴温40℃、電流密
度6A/dm2の条件で作成した。実施例2では光沢剤
を含まないスルファミン酸浴を用いて作成し、実施例3
では光沢剤を微量含むスルファミン酸浴を用いてめっき
し加熱後表層の硫黄を除去して作成した。また、上記銅
合金リードフレーム素材に光沢剤を添加したスルファミ
ン酸ニッケル浴でめっきしたもの、通常の無光沢ニッケ
ルめっき浴でめっきしたもの、及び通常の光沢ワット浴
でめっきしたものを比較例1〜3とし、それぞれの鏡面
反射率及び硫黄含有量を測定した。なお、比較例1〜3
のめっき厚はいずれも2μmである。Embodiments of the present invention will be described below. [Example 1] Fe: 0.1 wt% and P: 0.03 wt%
Was plated with nickel plating having a specular reflectance of 35% at 1.7 μm, and then nickel plating containing no sulfur was given at 0.3 μm. After plating, a stamping process was performed, and the specular reflectance and the sulfur content (from the surface, 0.1 to 0.3) shown in Examples 1 to 3 in Table 1 were obtained.
A copper alloy lead frame having a sulfur content of 1 μm or less was obtained. The nickel plating layer containing no sulfur was prepared in Example 1 using a matte watt bath under the conditions of a bath temperature of 40 ° C. and a current density of 6 A / dm 2 . Example 2 was prepared using a sulfamic acid bath containing no brightener.
Was prepared by plating using a sulfamic acid bath containing a trace amount of brightener, heating and removing sulfur from the surface layer. The copper alloy lead frame material was plated with a nickel sulfamate bath containing a brightener, plated with a normal matte nickel plating bath, and plated with a normal bright watt bath in Comparative Examples 1 to 3. 3, and the specular reflectance and sulfur content of each were measured. Comparative Examples 1 to 3
Is 2 μm.
【0020】[0020]
【表1】 [Table 1]
【0021】なお、実施例1の銅合金リードフレームの
表面硬さはビッカース硬度(荷重10g)Hv220で
あり、ニッケルの酸化はESCA分析におけるニッケル
酸化物ピーク強度とニッケル金属ピーク強度の比で(N
ioxide/Nimetal)=0.7であった。The surface hardness of the copper alloy lead frame of Example 1 is Vickers hardness (load: 10 g) Hv220, and the oxidation of nickel is determined by the ratio of the nickel oxide peak intensity to the nickel metal peak intensity in ESCA analysis as (N
(oxide / Nimetal) = 0.7.
【0022】これらの銅合金リードフレームを使用し、
還元雰囲気中(水素10%と酸素700ppmを含む窒
素ガス雰囲気)において、錫系はんだ(Sn−3.5%
Sb)を用いてはんだダイボンディング性を試験し、ま
たアルミニウム線によるワイヤボンディング性の試験を
行った。なお、本実施例における各試験方法は次の通り
である。 (表面硬さ)JISZ2251に準じ、試験荷重10g
fにてニッケルめっき表面よりビッカース硬さを測定し
た。 (鏡面反射率)JISZ8741に準じ、45度で光束
を入射し、鏡面反射において反射光束の入射光束に対す
る比を測定した。 (はんだダイボンディング性)10%水素を含む酸素濃
度700ppmの窒素ガス雰囲気中にて、銅合金リード
フレームを320℃のプレート上で1分加熱後、直径1
mmの鉛を含まないはんだ(錫96.5wt%、アンチ
モン3.5wt%)ボールを載せ、フラックスなし、撹
拌なしで、10秒後までにはんだボールが拡がった面積
を測定した。 (ワイヤボンディング性)5mil(125μm)のア
ルミニウム線(99.99%、Annealed)を用
いて、大気中、25℃で超音波(パルス60kHz)印
可法によるワイヤボンディング(ボンディング時間:1
00ms、荷重250g、UV出力5.5W)を行っ
た。次いで、接合されたアルミニウム線を真中で切断
し、アルミニウム線が銅合金リードフレームと接合され
ている2ndボンド部の接合状態を調査し(ツィザー強
度)、下記式によるワイヤ破断率を求めた。 ワイヤ破断率(%)=(ワイヤ破断した本数/全試験本
数)×100Using these copper alloy lead frames,
In a reducing atmosphere (a nitrogen gas atmosphere containing 10% of hydrogen and 700 ppm of oxygen), a tin-based solder (Sn-3.5%
The solder die bonding property was tested using Sb), and the wire bonding property test using an aluminum wire was performed. In addition, each test method in this example is as follows. (Surface hardness) Test load 10 g according to JISZ2251
At f, Vickers hardness was measured from the nickel plating surface. (Specular Reflectance) According to JIS Z8741, a light beam was incident at 45 degrees, and the ratio of the reflected light beam to the incident light beam in the specular reflection was measured. (Solder die bonding property) In a nitrogen gas atmosphere containing 10% hydrogen and an oxygen concentration of 700 ppm, a copper alloy lead frame is heated on a plate at 320 ° C. for 1 minute, and then has a diameter of 1 mm.
mm of lead-free solder (tin 96.5 wt%, antimony 3.5 wt%) balls were placed, and the area where the solder balls spread out after 10 seconds without flux and without stirring was measured. (Wire bonding property) Using an aluminum wire (99.99%, Annealed) of 5 mil (125 μm), wire bonding by an ultrasonic wave (pulse 60 kHz) application method at 25 ° C. in the air (bonding time: 1)
00 ms, a load of 250 g, and a UV output of 5.5 W). Next, the bonded aluminum wire was cut in the middle, the bonding state of the 2nd bond portion where the aluminum wire was bonded to the copper alloy lead frame was examined (tizer strength), and the wire breakage rate was calculated by the following equation. Wire breakage rate (%) = (number of broken wires / total number of test pieces) × 100
【0023】上記試験の結果と評価を表1に示す。な
お、表1において、はんだ拡がり面積の評価は、◎が非
常に良い、○が良い、×が悪いであり、ワイヤ破断率の
評価は○が100%、×が100%に満たないものであ
る。ニッケルめっきの鏡面反射率25%以上、表面から
0.1μm以内のニッケル層の硫黄含有量が0.000
5wt%以下という本発明に規定する要件を満たす実施
例1〜3は、還元雰囲気中の酸素濃度が700ppmと
高い状態で、フラックスなしで良好なはんだ拡がり、つ
まり優れたはんだダイボンディング性を示し、アルミニ
ウム線によるワイヤボンディングでもワイヤ破断率は1
00%と高い接合信頼性を示した。一方、比較例1は硫
黄含有量が高いため、酸素濃度の高い雰囲気ではんだ拡
がりが劣り、比較例2は鏡面反射率が低く表面が粗れて
おり、ワイヤボンディング性に劣る。比較例3は硫黄含
有量が高いため、酸素濃度の高い雰囲気ではんだ拡がり
が劣っていた。なお、比較例2は樹脂バリ除去性やはん
だ拡がりのコントロールも難しかった。Table 1 shows the results and evaluation of the above test. In Table 1, the evaluation of the solder spread area is as follows: ◎ is very good, ○ is good, X is bad, and the evaluation of the wire breakage rate is 100% for X and less than 100% for X. . Specular reflectance of nickel plating is 25% or more, sulfur content of nickel layer within 0.1 μm from surface is 0.000
Examples 1 to 3 satisfying the requirement of the present invention of 5 wt% or less show good solder spread without flux in a state where the oxygen concentration in the reducing atmosphere is as high as 700 ppm, that is, excellent solder die bonding properties. Wire breakage rate is 1 even with wire bonding with aluminum wire
The bonding reliability was as high as 00%. On the other hand, in Comparative Example 1, since the sulfur content is high, the solder spread is poor in an atmosphere having a high oxygen concentration, and in Comparative Example 2, the mirror reflectance is low and the surface is rough, and the wire bonding property is poor. In Comparative Example 3, since the sulfur content was high, the solder spread was poor in an atmosphere having a high oxygen concentration. In Comparative Example 2, it was difficult to control the removal of resin burrs and the spread of solder.
【0024】[実施例2]ここでは、最表面のニッケル
めっきに対するコバルト(Co)又はパラジウム(P
d)の添加効果(請求項2に対応)について試験した。
まず、[実施例1]に示した銅合金リードフレーム素材
に、光沢剤を含むニッケルめっきを1.7μm施し、そ
の上にCo、Pd、Co+Pdをそれぞれ添加した無光
沢ワット浴により、該合金元素を種々の割合で含有する
ニッケル(合金)めっきを0.3μm施した。めっき後
にスタンピング加工を施し、ニッケルめっきの鏡面反射
率が30%、表面から0.1μm以下の硫黄含有量が
0.0001%の銅合金リードフレームを得た。この銅
合金リードフレームの表面硬さはビッカース硬度Hv1
15であった。Example 2 Here, cobalt (Co) or palladium (P) was applied to nickel plating on the outermost surface.
The effect of adding d) (corresponding to claim 2) was tested.
First, the copper alloy lead frame material shown in [Example 1] was subjected to nickel plating containing a brightener at 1.7 μm, and Co, Pd, and Co + Pd were added thereto. (Alloy) plating containing 0.3% in various ratios. After plating, stamping was performed to obtain a copper alloy lead frame having a mirror reflectance of nickel plating of 30% and a sulfur content of 0.001% or less from the surface of 0.1 μm or less. The surface hardness of this copper alloy lead frame is Vickers hardness Hv1
It was 15.
【0025】この銅合金リードフレームに対し、[実施
例1]に示した要領ではんだダイボンディング性の試験
と、下記要領で加工性試験を行った。 (加工性試験)リード部を正逆方向に繰り返し曲げ加工
(内半径0.5mm、90°曲げ)し、破断するまでの
曲げ回数を求めた。The copper alloy lead frame was subjected to a solder die bonding property test as described in [Example 1] and a workability test as described below. (Workability test) The lead portion was repeatedly bent in the forward and reverse directions (inner radius 0.5 mm, bent at 90 °), and the number of bendings before breaking was determined.
【0026】上記試験の結果と評価を表2に示す。な
お、表2において、はんだ広がり面積の評価は[実施例
1]と同じであり、繰り返し曲げ回数の評価は、○が良
い、×が悪いである。0.5〜10.0wt%のCo又
はPdの一方又は双方を含有するという請求項2の要件
を満たす実施例4〜7は、酸素濃度が700ppmと高
い雰囲気でのはんだ拡がり面積が大きく、繰り返し曲げ
回数も多い。つまり、はんだダイボンディング性が非常
に優れ、加工性の低下も少ないという特性を示した。一
方、比較例4はCoの含有量が少ないため、はんだとの
拡散接合速度が遅く、はんだ拡がり面積の改善の度合が
小さく、比較例5、6はCo又はPdの含有量が高いた
め、加工性の低下が認められた。なお、比較例5、6で
は、はんだ耐熱剥離性の低下も認められた。Table 2 shows the results and evaluation of the above test. In Table 2, the evaluation of the solder spread area is the same as in [Example 1], and the evaluation of the number of times of repeated bending is ○ is good and X is bad. Examples 4 to 7 satisfying the requirement of claim 2 containing one or both of Co and Pd in an amount of 0.5 to 10.0 wt% have a large solder spread area in an atmosphere having an oxygen concentration as high as 700 ppm, and have a high repetition rate. Many bends. In other words, the characteristics were that the solder die bonding property was very excellent and the workability was hardly reduced. On the other hand, Comparative Example 4 has a low Co content, so the diffusion bonding speed with the solder is low, and the degree of improvement of the solder spread area is small. Comparative Examples 5 and 6 have a high Co or Pd content, and A decrease in sex was observed. In Comparative Examples 5 and 6, a decrease in the soldering heat-peelability was also observed.
【0027】[0027]
【表2】 [Table 2]
【0028】[0028]
【発明の効果】本発明のニッケルめっき銅合金リードフ
レームは、鉛を含まない錫系はんだと良好なぬれを示
し、半導体組立工程中の酸素濃度が高い雰囲気でも、フ
ラックスなしで銀めっき品と同等のはんだ拡がりを得る
ことができ、はんだ拡がりコントロールも可能で、優れ
たはんだダイボンディング性を示す。さらに、アルミニ
ウム線と良好なワイヤボンディング性を持つほか、加工
性の低下もなく、生産性、作業性に優れた特性を示す。The nickel-plated copper alloy lead frame of the present invention exhibits good wettability with a lead-free tin-based solder, and is equivalent to a silver-plated product without flux even in an atmosphere having a high oxygen concentration during a semiconductor assembly process. The solder spread can be obtained, the solder spread can be controlled, and excellent solder die bonding property is exhibited. In addition, it has good wire bonding properties with aluminum wires, does not reduce workability, and exhibits excellent properties in productivity and workability.
Claims (2)
上であり、表面から0.1μm以内のニッケル中の硫黄
含有量が0.0005wt%以下であることを特徴とす
るはんだダイボンディング用ニッケルめっき銅合金リー
ドフレーム。1. A nickel plating for solder die bonding, wherein the nickel plating has a mirror reflectance of 25% or more, and the sulfur content in nickel within 0.1 μm from the surface is 0.0005% by weight or less. Copper alloy lead frame.
0.0wt%のコバルト又はパラジウムの一方又は双方
を含有することを特徴とする請求項1に記載されたはん
だダイボンディング用ニッケルめっき銅合金リードフレ
ーム。2. The nickel plating on the outermost surface is 0.5-1.
The nickel-plated copper alloy lead frame for solder die bonding according to claim 1, further comprising 0.0 wt% of one or both of cobalt and palladium.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP34868495A JP3116332B2 (en) | 1995-12-18 | 1995-12-18 | Nickel-plated copper alloy lead frame for solder die bonding |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP34868495A JP3116332B2 (en) | 1995-12-18 | 1995-12-18 | Nickel-plated copper alloy lead frame for solder die bonding |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH09172124A JPH09172124A (en) | 1997-06-30 |
JP3116332B2 true JP3116332B2 (en) | 2000-12-11 |
Family
ID=18398667
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP34868495A Expired - Lifetime JP3116332B2 (en) | 1995-12-18 | 1995-12-18 | Nickel-plated copper alloy lead frame for solder die bonding |
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JP (1) | JP3116332B2 (en) |
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JP2000064084A (en) * | 1998-08-20 | 2000-02-29 | Kobe Steel Ltd | Plating material for heat radiating board of electronic parts |
JP2002334960A (en) * | 2001-05-07 | 2002-11-22 | Leadmikk Ltd | Satisfactory printable heat-dissipating material |
JP2004119944A (en) * | 2002-09-30 | 2004-04-15 | Toyota Industries Corp | Semiconductor module and mounting substrate |
JP4274245B2 (en) | 2004-12-03 | 2009-06-03 | 株式会社村田製作所 | Electrical contact parts, coaxial connectors, and electrical circuit devices using them |
JP2015149370A (en) * | 2014-02-06 | 2015-08-20 | 日立オートモティブシステムズ株式会社 | Semiconductor device and manufacturing method of the same |
JP6152842B2 (en) * | 2014-11-04 | 2017-06-28 | トヨタ自動車株式会社 | Semiconductor device and manufacturing method thereof |
-
1995
- 1995-12-18 JP JP34868495A patent/JP3116332B2/en not_active Expired - Lifetime
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