JPH05230675A - Discoloring preventive solution for copper - Google Patents
Discoloring preventive solution for copperInfo
- Publication number
- JPH05230675A JPH05230675A JP4069806A JP6980692A JPH05230675A JP H05230675 A JPH05230675 A JP H05230675A JP 4069806 A JP4069806 A JP 4069806A JP 6980692 A JP6980692 A JP 6980692A JP H05230675 A JPH05230675 A JP H05230675A
- Authority
- JP
- Japan
- Prior art keywords
- copper
- silver
- benzotriazole
- solution
- discoloration
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
- C23F11/14—Nitrogen-containing compounds
- C23F11/149—Heterocyclic compounds containing nitrogen as hetero atom
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
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- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
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- H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
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- H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
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- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/45099—Material
- H01L2224/451—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
- H01L2224/45138—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
- H01L2224/45144—Gold (Au) as principal constituent
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- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
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- H01L2224/481—Disposition
- H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/48225—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
- H01L2224/48227—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
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- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
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- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
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- H01L2224/481—Disposition
- H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
- H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
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- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/484—Connecting portions
- H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
- H01L2224/48465—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
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- H—ELECTRICITY
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- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
- H01L2224/732—Location after the connecting process
- H01L2224/73251—Location after the connecting process on different surfaces
- H01L2224/73265—Layer and wire connectors
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- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01019—Potassium [K]
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- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01029—Copper [Cu]
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- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01047—Silver [Ag]
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- H01L2924/10155—Shape being other than a cuboid
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- H01L2924/10155—Shape being other than a cuboid
- H01L2924/10157—Shape being other than a cuboid at the active surface
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- H01L2924/181—Encapsulation
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Wire Bonding (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、銅の変色防止液に関す
るものであり、特には反復使用中被処理部品表面のワイ
ヤボンディング性を損なうことのない銅の変色防止液及
びその使用方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper discoloration preventive liquid, and more particularly to a copper discoloration preventive liquid which does not impair the wire bondability of the surface of a component to be treated during repeated use and a method of using the same. Is.
【０００２】[0002]
【従来の技術】最近、リードフレーム等の電子部品材料
に高速部分銀めっきを行うことが多くなっている。例え
ば、金製のボンディングワイヤーを使用してのボンディ
ングに際しては、その接合性の向上のためにリードフレ
ームのボンディング部分には高速部分銀めっきが施され
る。この高速部分銀めっきは、通常以下のようにして行
われる。先ず、リードフレーム等の電子部品材料に用い
られる基材を脱脂及び酸洗後、被覆される銀めっき皮膜
と基材との密着性を良くするため、通常銅ストライクめ
っき又は銅若しくは銅合金めっき処理（以下、本明細書
では、これらを総称して銅ストライクめっき処理と呼
ぶ）が施される。次に、銅ストライクめっき処理が施さ
れた基材は、水洗後、基材を銀めっき液に浸漬した時に
銀の置換析出を防止するための前処理を行った後、必要
部分のみに高速電気銀めっきを行う。2. Description of the Related Art Recently, high-speed partial silver plating has been frequently performed on electronic parts materials such as lead frames. For example, at the time of bonding using a gold bonding wire, high-speed partial silver plating is applied to the bonding portion of the lead frame to improve the bondability. This high-speed partial silver plating is usually performed as follows. First, after degreasing and pickling base materials used for electronic component materials such as lead frames, in order to improve the adhesion between the silver plating film to be coated and the base material, usually copper strike plating or copper or copper alloy plating treatment is performed. (Hereinafter, these are collectively referred to as a copper strike plating treatment). Next, the base material that has been subjected to copper strike plating treatment is washed with water and then subjected to pretreatment to prevent substitutional precipitation of silver when the base material is immersed in a silver plating solution. Perform silver plating.
【０００３】ところがこの銀めっきにおいて、種々の理
由により、前記基材の銀めっき不要部分にも銀がめっき
又は析出することが多い。このような銀の異常析出部を
放置しておくと、銀のマイグレーションが起る可能性が
あり、電子部品材料の信頼性が低下する。従って、通
常、このような銀の異常析出部は、公知の銀の剥離液を
用いて選択的に溶解除去される。However, in this silver plating, silver is often plated or deposited on a portion of the base material where the silver plating is unnecessary for various reasons. If such an abnormal silver precipitation portion is left as it is, silver migration may occur, and the reliability of the electronic component material decreases. Therefore, normally, such abnormal silver deposits are selectively dissolved and removed by using a known silver stripping solution.
【０００４】ところが、この様にして製造されたリード
フレーム等の電子部品材料の運搬、貯蔵等を行っている
場合等において、銀を剥離した後に露出した、銅基材表
面若しくは銅ストライクめっき処理を施した銅めっき
面、特にこれら電子部品材料を重ねた部分が変色すると
いう問題点があることが近年認識されるようになってき
た。However, when the electronic component material such as the lead frame manufactured in this way is transported, stored, etc., the copper substrate surface or the copper strike plating treatment exposed after peeling silver is performed. In recent years, it has been recognized that there is a problem that the applied copper-plated surface, especially the portion where these electronic component materials are overlapped, is discolored.
【０００５】この変色原因については、現在の所では明
確な結論は出ていないが、変色部には酸化銅が生成して
いることが確認されていることから、(1) 銀を剥離した
直後なので、銅表面が活性であること、(2) 銀と銅との
間に電位差が発生し銅表面が活性となること等の理由に
より銅面が酸化されているものと考えられる。この銅面
の酸化変色は、はんだ付性が悪くなること、酸化さ
れた銅が剥れて、短絡の恐れがあること等の理由により
電子部品材料の信頼性を低下させるため現在大きな問題
となりつつある。Regarding the cause of this discoloration, no clear conclusion has been reached at present, but it has been confirmed that copper oxide is generated in the discolored part. Therefore, (1) immediately after peeling silver Therefore, it is considered that the copper surface is oxidized due to the fact that the copper surface is active and (2) the potential difference is generated between silver and copper to activate the copper surface. This oxidative discoloration of the copper surface is currently becoming a major problem because it deteriorates the reliability of electronic component materials due to reasons such as poor solderability, peeling of oxidized copper, and risk of short circuit. is there.
【０００６】この問題を解決するために、本件出願人は
先に、特願平２−２８３３７３号において、銅若しくは
銅合金基材表面又は金属材料に銅若しくは銅合金をめっ
きした基材表面に、銀めっきし、該銀めっきの不要部分
に付着した銀を剥離した後、前記銀剥離面の銅の変色を
防止するための処理液として、銅の変色防止剤として５
−メチル・１Ｈ−ベンゾトリアゾール、５，６−ジメチ
ル・１Ｈ−ベンゾトリアゾール及び２−メルカプトピリ
ミジンから選ばれる１種又は２種以上を含有する無機酸
及び／又は有機酸の酸性溶液からなる銅変色防止液を提
唱した。この銅変色防止液は更にｐＨ緩衝剤をも含有す
ることができる。この銅変色防止液は非常に有用で、多
方面への今後の活用が期待されている。使用に当たって
は、銀を剥離した基材を変色防止液に浸漬しそして乾燥
するだけでよい。中でも、最も広範囲の酸性領域で有用
であるのは、変色防止剤として５−メチル・１Ｈ−ベン
ゾトリアゾール及び／又は５，６−ジメチル・１Ｈ−ベ
ンゾトリアゾールのベンゾトリアゾール誘導体を含有す
る無機酸及び／又は有機酸の酸性溶液からなる銅変色防
止液である。[0006] In order to solve this problem, the applicant of the present invention has previously proposed in Japanese Patent Application No. 2-283373 that the surface of a copper or copper alloy substrate or the surface of a substrate obtained by plating a metal material with copper or a copper alloy is After silver plating and peeling off the silver adhering to unnecessary portions of the silver plating, as a treatment liquid for preventing the discoloration of copper on the silver peeled surface, a copper discoloration inhibitor 5
-Copper discoloration prevention comprising an acidic solution of an inorganic acid and / or an organic acid containing one or more selected from methyl- 1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole and 2-mercaptopyrimidine Proposed liquid. The copper discoloration preventing liquid may further contain a pH buffering agent. This copper anti-tarnish solution is very useful and is expected to be utilized in various fields in the future. In use, the silver stripped substrate need only be immersed in the tarnish preventative solution and dried. Among them, what is useful in the widest range of acidic regions is an inorganic acid containing a benzotriazole derivative of 5-methyl.1H-benzotriazole and / or 5,6-dimethyl.1H-benzotriazole as a discoloration inhibitor, and / or Alternatively, it is a copper discoloration preventing liquid consisting of an acidic solution of an organic acid.
【０００７】[0007]
【発明が解決しようとする課題】ところが、この銅変色
防止液の反復使用中、処理された基材をワイヤボンディ
ング、ダイボンディングその他のボンディング加工処理
する際、ボンディング性が劣化することが改めて認識さ
れるようになった。However, during repeated use of this copper discoloration preventing liquid, it was recognized again that the bondability deteriorates when the treated substrate is subjected to wire bonding, die bonding or other bonding processing. It became so.
【０００８】特に、最近のワイヤボンディング時の温度
は低温化する傾向があり、２００℃の例さえある。ベン
ゾトリアゾール誘導体は、２１０℃以上で揮発すること
から従来の２３０℃以上のボンディング温度では例え銀
面に吸着しても問題はさほど顕在化しなかったが、低温
時においてはボンディング密着強度の悪化が特に問題化
したのである。Particularly, the temperature at the time of recent wire bonding tends to be lowered, and even 200 ° C. is an example. Since the benzotriazole derivative volatilizes at 210 ° C. or higher, at a conventional bonding temperature of 230 ° C. or higher, even if it is adsorbed on the silver surface, the problem does not become so obvious, but the bonding strength is particularly deteriorated at low temperatures. It became a problem.
【０００９】本発明の課題は、変色防止剤として５−メ
チル・１Ｈ−ベンゾトリアゾール及び／又は５，６−ジ
メチル・１Ｈ−ベンゾトリアゾールのベンゾトリアゾー
ル誘導体を含有する無機酸及び／又は有機酸の酸性溶液
からなる銅変色防止液の有効寿命を銅変色防止液の本来
の変色防止作用を悪化することなく延長する対策を確立
することである。An object of the present invention is to acidify an inorganic acid and / or an organic acid containing a benzotriazole derivative of 5-methyl.1H-benzotriazole and / or 5,6-dimethyl.1H-benzotriazole as a discoloration preventing agent. It is necessary to establish a measure to extend the effective life of the copper discoloration preventing solution consisting of a solution without deteriorating the original discoloration preventing action of the copper discoloration preventing solution.
【００１０】[0010]
【問題点を解決するための手段】ボンディング性の劣化
の原因を追及した結果、銀剥離液に浸漬して銀剥離後、
水洗し、銅変色防止液に浸漬する一連の工程において、
銅変色防止液の銅溶出による汚染が原因であることが判
明した。即ち、銅変色防止液に溶出銅が蓄積してくる
と、汚染のない銅変色防止液においては本来銅面のみに
吸着し、銀面には吸着しないはずのベンゾトリアゾール
誘導体が、銅面のみならず、銀面にも吸着して有機皮膜
を形成するため、ボンディング性の劣化が生じることを
究明するに至った。そこで、銅汚染液において、銀面に
ベンゾトリアゾール誘導体の吸着が起こらないようにす
る手段として、各種添加剤を検討した結果、ＥＤＴＡキ
レート剤が有効であることが判明した。[Means for Solving Problems] As a result of investigating the cause of the deterioration of the bonding property, after immersion in a silver stripping solution and silver stripping,
In a series of steps of washing with water and immersing in a copper discoloration prevention solution,
It was revealed that the contamination was caused by the copper elution of the copper discoloration preventing liquid. That is, when the eluted copper accumulates in the copper discoloration preventing liquid, the benzotriazole derivative, which is originally adsorbed only on the copper surface and does not adsorb on the silver surface in the copper discoloration preventing liquid without contamination, is the copper surface only. However, since it is adsorbed on the silver surface to form an organic film, it has been clarified that the bondability is deteriorated. Then, as a result of examining various additives as a means for preventing the adsorption of the benzotriazole derivative on the silver surface in the copper contaminated liquid, it was found that the EDTA chelating agent is effective.
【００１１】この知見に基づいて、本発明は、変色防止
剤として５−メチル・１Ｈ−ベンゾトリアゾール及び／
又は５，６−ジメチル・１Ｈ−ベンゾトリアゾールから
選択されるベンゾトリアゾール誘導体を含有する無機酸
及び／又は有機酸の酸性溶液にＥＤＴＡキレート剤を添
加したことを特徴とする銅変色防止液を提供する。更
に、ＥＤＴＡキレート剤の別の使用態様として、本発明
は、変色防止剤として５−メチル・１Ｈ−ベンゾトリア
ゾール及び／又は５，６−ジメチル・１Ｈ−ベンゾトリ
アゾールから選択されるベンゾトリアゾール誘導体を含
有する無機酸及び／又は有機酸の酸性溶液からなる銅変
色防止液の使用中、該銅変色防止液の劣化が起こること
を防ぐためにＥＤＴＡキレート剤を添加することを特徴
とする銅変色防止液使用方法を提供するものである。銅
変色防止液はｐＨ緩衝剤を含むことができる。代表的な
銅変色防止液は、ピロ燐酸カリウム：１〜１００ｇ／
ｌ、５−メチル・１Ｈ−ベンゾトリアゾール：０．０１
〜１０ｇ／ｌ及びＥＤＴＡ：０．０３〜６ｇ／ｌを含
み、ｐＨ：１〜７のものである。On the basis of this finding, the present invention provides 5-methyl.1H-benzotriazole and / or
Alternatively, there is provided a copper discoloration preventing liquid, characterized in that an EDTA chelating agent is added to an acidic solution of an inorganic acid and / or an organic acid containing a benzotriazole derivative selected from 5,6-dimethyl.1H-benzotriazole. .. Furthermore, as another aspect of the use of the EDTA chelating agent, the present invention contains a benzotriazole derivative selected from 5-methyl 1H-benzotriazole and / or 5,6-dimethyl 1H-benzotriazole as a discoloration inhibitor. Use of a copper anti-tarnish solution characterized by adding an EDTA chelating agent in order to prevent deterioration of the copper anti-tarnish solution during use of the copper anti-tarnish solution comprising an acidic solution of an inorganic acid and / or an organic acid. It provides a method. The copper anti-tarnish solution may include a pH buffer. A typical copper discoloration preventing liquid is potassium pyrophosphate: 1 to 100 g /
1,5-methyl-1H-benzotriazole: 0.01
-10 g / l and EDTA: 0.03-6 g / l, pH: 1-7.
【００１２】本発明において、「ＥＤＴＡキレート剤」
とは、ＥＤＴＡ（エチレンジアミン四酢酸）及びその誘
導体を包括するものである。In the present invention, "EDTA chelating agent"
The term includes EDTA (ethylenediaminetetraacetic acid) and its derivatives.
【００１３】[0013]
【作用】ＥＤＴＡキレート剤は、銅変色防止液中で銅を
安定化した形で液中に溶存させることにより、ベンゾト
リアゾール誘導体が銀面に吸着するのを防止する。それ
により、銀面はベンゾトリアゾールの吸着のない清浄な
状態に維持され、露出銅のみが銅変色防止液の作用でそ
の変色を有効に防止されると共に、銀面のボンディング
性は良好に維持される。しかも、ＥＤＴＡキレート剤
は、銅変色防止液の本来の変色防止作用を悪化しない。The EDTA chelating agent prevents the benzotriazole derivative from adsorbing on the silver surface by dissolving copper in the copper discoloration preventing solution in a stabilized form in the solution. As a result, the silver surface is maintained in a clean state without adsorption of benzotriazole, only the exposed copper is effectively prevented from discoloring by the action of the copper discoloration preventing liquid, and the bondability of the silver surface is maintained well. It Moreover, the EDTA chelating agent does not deteriorate the original discoloration preventing action of the copper discoloration preventing liquid.
【００１４】[0014]
【実施例】まず、本発明において用いられる基材は、リ
ードフレーム等の電子部品材料が主であり、これらは通
常銅、銅合金、鉄、鉄合金、ニッケル、ニッケル合金及
びこれらをめっきしたものなどの銀より卑な金属のいず
れかから成るものである。これらは通常、脱脂、酸洗
後、必要に応じ銅ストライクめっき処理が施される。こ
の処理は基材と密着性の良い銀皮膜を得るために行うも
のであり、基材が銅、銅合金及びこれらをめっきしたも
のでかつ銀めっき密着性が良い場合には省略することも
出来る。EXAMPLES First, the base material used in the present invention is mainly an electronic component material such as a lead frame, and these are usually copper, copper alloy, iron, iron alloy, nickel, nickel alloy and those plated with these. It is composed of one of the metals that is less base than silver. These are usually degreased and pickled, and then subjected to copper strike plating if necessary. This treatment is performed in order to obtain a silver film having good adhesion to the base material, and can be omitted if the base material is copper, a copper alloy, or a product obtained by plating these and the silver plating adhesion is good. ..
【００１５】銅ストライクめっき浴の種類及び処理等の
条件は当業界で採用されている公知のもので良く、目的
に応じ適宜選択すれば良い。なお、本発明において、
『銅若しくは銅合金又は金属材料に銅若しくは銅合金を
めっきした基材』とは、銅、銅合金のみならず鉄、鉄合
金、ニッケル、ニッケル合金などの銀より卑な金属に銅
ストライクめっき処理を施したものすべてを包含する。
当然のことながら、銅ストライクめっき処理等は、必要
に応じ複数回行っても良い。Conditions such as the type and treatment of the copper strike plating bath may be those known in the art and may be appropriately selected according to the purpose. In the present invention,
"Copper or a copper alloy or a base material obtained by plating copper or a copper alloy on a metal material" means copper strike plating treatment not only on copper and copper alloys but also on metals less base than silver such as iron, iron alloys, nickel and nickel alloys. Including all that have been subjected to.
As a matter of course, the copper strike plating treatment and the like may be performed plural times as needed.
【００１６】次に、前記銅ストライクめっき処理等が施
された基材は、水洗後、通常は、銀めっきの前処理液
（銀置換防止液）へ浸漬される。この理由は、高速銀め
っき液は銀濃度が高く、銀より卑な金属からなる基材を
浸漬すると、浸漬しただけで銀が大量に置換析出し、こ
の置換析出銀層は基材に対する密着性が極めて悪く、こ
の上に銀を電気めっきしても密着性は改善されず、従っ
て、めっき皮膜の剥れ、加熱時のふくれや変色を生ずる
等の結果を呈することになり、銀めっき層の基材への密
着性は極めて劣悪なものとなる上に、基材のめっき不要
部分も銀で被覆されてしまうため、高価格な銀の損失と
なり、まためっき液が銀との置換反応によって溶出した
銅など卑金属のイオンにより汚染されてしまう等の問題
点があるからである。Next, the base material that has been subjected to the copper strike plating treatment, etc., after being washed with water, is usually immersed in a pretreatment liquid for silver plating (silver substitution preventing liquid). The reason for this is that the high-speed silver plating solution has a high silver concentration, and when a base material made of a metal less base than silver is dipped, a large amount of silver is displacement-deposited just by soaking, and the substitution-deposited silver layer has an adhesiveness to the substrate. The adhesion is not improved even if silver is electroplated on this, and therefore, the results such as peeling of the plating film, swelling and discoloration during heating, etc. are exhibited. The adhesion to the base material is extremely poor, and the unnecessary plating of the base material is also covered with silver, resulting in high-priced silver loss, and the plating solution elutes due to the substitution reaction with silver. This is because there is a problem that it is contaminated with ions of base metal such as copper.
【００１７】銀めっきの前処理液は、このような銀の置
換防止剤を含有しており、基材表面に薄い置換防止皮膜
を形成することにより銀の置換析出を防止するものであ
り、その種類に特に限定はなく例えば、チオカルボン酸
又はその塩（特開昭６０−１９０５８９参照）、２，
２′−ジピリジル等の含窒素複素環化合物（特開昭６０
−１９０５９１参照）及び２−チオバルビツル酸等のチ
オウレイレン基を環内に含む化合物（特公平１−３２３
１８参照）等を含めて公知のもので良い。The pretreatment liquid for silver plating contains such a silver anti-displacement agent and prevents substitutional precipitation of silver by forming a thin anti-displacement film on the substrate surface. The kind is not particularly limited, and examples thereof include thiocarboxylic acid or a salt thereof (see JP-A-60-190589), 2,
Nitrogen-containing heterocyclic compounds such as 2'-dipyridyl (JP-A-60
-190591) and a compound containing a thioureylene group such as 2-thiobarbituric acid in the ring (Japanese Patent Publication No. 1-323).
18)) and the like, and other known ones may be used.
【００１８】そして、前処理された基材は銀めっき液へ
浸漬され、電気めっきにより銀めっきされる。なお、銀
めっき液中に前記置換析出防止剤が添加してある場合
は、前記前処理を省くこともできる。Then, the pretreated base material is dipped in a silver plating solution and silver-plated by electroplating. When the substitution precipitation inhibitor is added to the silver plating solution, the pretreatment can be omitted.
【００１９】銀めっき液は、シアン化銀アルカリの形で
含有された銀の濃度が１０〜１００ｇ／ｌ、フリーのシ
アン化合物の濃度が１０ｇ／ｌ以下である高速銀めっき
液である。シアン化銀アルカリとしてはシアン化銀カリ
ウムが最良でありまた液の電気電導性を向上させ、ｐＨ
を７．５〜９．０の範囲内に緩衝する効果を持つ塩とし
て、リン酸、ピロリン酸、クエン酸のアルカリ金属塩や
硼酸を含有する。The silver plating solution is a high speed silver plating solution in which the concentration of silver contained in the form of silver cyanide is 10 to 100 g / l and the concentration of free cyan compound is 10 g / l or less. As the silver cyanide alkali, silver cyanide potassium is the best and also improves the electric conductivity of the liquid,
As a salt having a buffering effect within the range of 7.5 to 9.0, phosphoric acid, pyrophosphoric acid, an alkali metal salt of citric acid or boric acid is contained.
【００２０】以上のような処理により、基材の銀めっき
必要部分のみに銀めっきが施されるが、種々の理由によ
り、基材の銀めっき不要部分に銀がめっき又は析出する
ことが多い。前述したように、このような銀の異常析出
部を放置しておくと、銀のマイグレーションが起る可能
性があり、電子部品材料の信頼性が低下する。By the above-mentioned treatment, silver is plated only on the portion of the base material where silver plating is required, but for various reasons, silver is often plated or deposited on the portion of the base material which does not require silver plating. As described above, if such an abnormal silver precipitation portion is left as it is, silver migration may occur and the reliability of the electronic component material decreases.
【００２１】そこで、通常、このような銀異常析出部は
公知の銀の剥離液を用いて選択的に溶解除去する。当
然、銀剥離後には、その下側の銅面が新たに露出し、こ
の銅表面は酸化により変色してはんだ付性を悪くし、ま
た酸化された銅が剥れて、短絡を生じやすい等の理由に
より電子部品材料の信頼性を低下させる。Therefore, such abnormal silver deposits are usually selectively removed by dissolution using a known silver stripping solution. Naturally, after the silver is peeled off, the copper surface underneath is newly exposed, and this copper surface is discolored by oxidation to deteriorate solderability, and the oxidized copper is peeled off, which may cause a short circuit. The reason is that the reliability of the electronic component material is reduced.
【００２２】そこで、この銀を剥離した後、基材を本発
明に従う銅変色防止液に浸漬し、銅の変色を防止し、電
子部品材料の信頼性を向上させる。Therefore, after the silver is peeled off, the substrate is immersed in the copper discoloration preventing liquid according to the present invention to prevent the discoloration of copper and improve the reliability of the electronic component material.
【００２３】ここで、説明の便宜上、リードフレームに
よるＩＣ実装例の状態を図１を参照して説明する。ここ
では、リードフレーム１は、ＩＣチップ２における電極
３と外部電源或いは素子（図示なし）を接続するもので
あり、これはリードフレームのリード部４とアイランド
（パッド）５に搭載されたＩＣチップ２の電極３とをボ
ンディングワイヤ６により接続することにより行なわれ
る。これら接続部全体が封止樹脂７により封止される。
通常、アイランドのＩＣチップ搭載部８及びワイヤボン
ディングされるリード部先端部９がその他の必要部分と
併せて局所的に銀めっきされる。この部分銀メッキが、
上述した高速銀めっきにより実施される。銀めっきは、
リード部とＩＣチップ電極とをボンディングワイヤ６に
より接続するワイヤボンディング或いはＩＣチップをア
イランドに結合するダイボンディングにおいてボディン
グを強固にするために必要とされる。銀めっき皮膜は、
必要部分以外にも不可避的に形成され、そのため、上述
した通り不要部分は銀剥離液により除去されそして露出
した銅表面部分とリード部銅表面の変色を防止するため
に銅変色防止液に浸漬処理されるのである。ところが、
先に提唱された銅変色防止剤を使用すると、その使用が
繰り返されるにつれ、溶出銅が銅変色防止液中に蓄積
し、汚染のない銅変色防止液においては本来銅面のみに
吸着し、銀面には吸着しないはずのベンゾトリアゾール
誘導体が、銅面のみならず、例えば９に示したような銀
面にも吸着して有機皮膜を形成するため、そこへのワイ
ヤボンディングに際してのボンディング性に悪影響を与
えたのである。特に、リード部４とボンディングワイヤ
６との結合部１０がそのボンディング性に重大な影響を
受けた。これは、当該結合部１０上にベンゾトリアゾー
ル誘導体が吸着しているためである。Here, for convenience of explanation, a state of an IC mounting example using a lead frame will be described with reference to FIG. Here, the lead frame 1 connects the electrodes 3 in the IC chip 2 to an external power source or an element (not shown). This is the IC chip mounted on the lead portion 4 and the island (pad) 5 of the lead frame. This is performed by connecting the second electrode 3 with the bonding wire 6. The entire connecting portion is sealed with the sealing resin 7.
Usually, the IC chip mounting portion 8 of the island and the tip portion 9 of the lead portion to be wire-bonded are locally silver-plated together with other necessary portions. This partial silver plating
It is implemented by the high speed silver plating described above. Silver plating
It is necessary for wire bonding for connecting the lead portion and the IC chip electrode with the bonding wire 6 or for die bonding for bonding the IC chip to the island in order to strengthen the bonding. The silver plating film is
It is inevitably formed in areas other than the necessary areas, so unnecessary areas are removed by silver stripping solution as described above, and exposed to copper discoloration prevention solution to prevent discoloration of exposed copper surface areas and lead copper surfaces. Is done. However,
When the previously proposed copper anti-tarnish agent is used, as its use is repeated, eluted copper accumulates in the copper anti-tarnish solution, and in a copper anti-tarnish solution without contamination, it is originally adsorbed only on the copper surface and silver. The benzotriazole derivative, which should not be adsorbed on the surface, adsorbs not only on the copper surface but also on the silver surface as shown in 9, for example, to form an organic film, which adversely affects the bondability during wire bonding. Was given. In particular, the bondability of the bonding portion 10 between the lead portion 4 and the bonding wire 6 was seriously affected. This is because the benzotriazole derivative is adsorbed on the bonding portion 10.
【００２４】最近のワイヤボンディング時の温度は低温
化する傾向があり、２００℃の例さえある。ベンゾトリ
アゾール誘導体は、２１０℃以上で揮発することから従
来の２３０℃以上のボンディング温度では例え銀面に吸
着しても問題はさほど顕在化しなかったが、低温時にお
いてはボンディング密着強度の悪化が特に問題となって
きたのである。The temperature at the time of recent wire bonding tends to be lowered, and even 200 ° C. is an example. Since the benzotriazole derivative volatilizes at 210 ° C. or higher, at a conventional bonding temperature of 230 ° C. or higher, even if it is adsorbed on the silver surface, the problem does not become so obvious, but the bonding strength is particularly deteriorated at low temperatures. It has become a problem.
【００２５】本発明に従えば、こうした銀めっき部分へ
のベンゾトリアゾール誘導体の吸着を防止することの出
来る銅変色防止液が使用される。本発明の銅変色防止液
は、先に提唱された変色防止剤として５−メチル・１Ｈ
−ベンゾトリアゾール及び／又は５，６−ジメチル・１
Ｈ−ベンゾトリアゾールのベンゾトリアゾール誘導体を
含有する無機酸及び／又は有機酸の酸性溶液にＥＤＴＡ
キレート剤を添加したことを特徴とする。ＥＤＴＡキレ
ート剤は、銅変色防止液中で銅を安定化した形で液中に
溶存させることによりベンゾトリアゾール誘導体が銀面
に吸着するのを防止する。According to the present invention, a copper discoloration preventing liquid which can prevent the adsorption of the benzotriazole derivative on the silver-plated portion is used. The copper anti-tarnish solution of the present invention is used as a previously proposed anti-tarnish agent, 5-methyl-1H.
-Benzotriazole and / or 5,6-dimethyl-1
EDTA in an acidic solution of an inorganic acid and / or an organic acid containing a benzotriazole derivative of H-benzotriazole
It is characterized by adding a chelating agent. The EDTA chelating agent prevents the benzotriazole derivative from adsorbing on the silver surface by dissolving copper in the copper discoloration preventing solution in a stabilized form in the solution.
【００２６】本発明の銅の変色防止液において、液を酸
性とした理由は、変色防止剤としての５−メチル・１Ｈ
−ベンゾトリアゾール、５，６−ジメチル・１Ｈ−ベン
ゾトリアゾールのベンゾトリアゾール誘導体が、アルカ
リ性にすると銅の変色防止効果が半減し、事実上使用出
来ないからである。従って、本発明でいう酸性とは、ｐ
Ｈ７以下の領域を意味し、好ましいｐＨは１〜６、更に
好ましくは３〜５である。ｐＨを１未満にすると銅スト
ライクめっき処理等が施された処理面が浸食される恐れ
があるので好ましくない。ｐＨは例えば燐酸、水酸化ナ
トリウム等を用いて調整される。In the copper tarnish preventive solution of the present invention, the reason for making the solution acidic is that 5-methyl.1H as a tarnish preventer is used.
This is because when the benzotriazole derivative of benzotriazole or 5,6-dimethyl-1H-benzotriazole is made alkaline, the effect of preventing discoloration of copper is halved and it cannot be practically used. Therefore, the term "acidic" in the present invention means p
It means a region of H7 or less, and a preferable pH is 1 to 6, and more preferably 3 to 5. If the pH is less than 1, the treated surface that has been subjected to the copper strike plating treatment may be corroded, which is not preferable. The pH is adjusted using, for example, phosphoric acid, sodium hydroxide or the like.
【００２７】変色防止液のｐＨを酸性とする酸としては
無機酸、有機酸のいずれでも良く、又これらを混合して
使用しても良い。無機酸としては、硫酸、硝酸、塩酸、
燐酸等が例示され、有機酸としては、クエン酸、スルフ
ァミン酸、酢酸、酒石酸等が例示されるが、特にこれら
に限定されるものではない。但し、基材及びめっき表面
への影響を考慮に入れると燐酸又はクエン酸が特に好ま
しい。The acid for making the pH of the discoloration preventing solution acidic may be either an inorganic acid or an organic acid, or may be a mixture of these. As the inorganic acid, sulfuric acid, nitric acid, hydrochloric acid,
Phosphoric acid and the like are exemplified, and as the organic acid, citric acid, sulfamic acid, acetic acid, tartaric acid and the like are exemplified, but the organic acid is not particularly limited thereto. However, phosphoric acid or citric acid is particularly preferable in consideration of the influence on the substrate and the plating surface.
【００２８】一方、ベンゾトリアゾール誘導体変色防止
剤の添加量は、酸に対する溶解度以下であれば特に限定
されることはないが、液の持ち出しを考えるとあまり高
濃度にすることは経済的ではない。従って、添加量は変
色防止効果から一般的に５〜２００mg／ｌ程度で十分と
考えられるが、場合によっては１〜１０ｇ／ｌ程度の添
加でも良く、処理条件を考慮に入れ適宜選択すれば良
い。On the other hand, the amount of the benzotriazole derivative discoloration inhibitor added is not particularly limited as long as it is not more than the solubility in acid, but it is not economical to make the concentration too high in consideration of taking out the liquid. Therefore, it is generally considered that the addition amount is about 5 to 200 mg / l from the viewpoint of discoloration prevention effect, but in some cases, about 1 to 10 g / l may be added, and it may be appropriately selected in consideration of treatment conditions. ..
【００２９】また、このような変色防止液を長期に連続
して使用する場合には、使用中のｐＨの変動を極力少な
くするため、公知のｐＨ緩衝剤を添加しておくことが好
ましい。When such a discoloration preventing liquid is continuously used for a long period of time, it is preferable to add a known pH buffering agent in order to minimize the fluctuation of pH during use.
【００３０】ＥＤＴＡキレート剤は、銅変色防止液中で
蓄積した銅を安定化した形で液中に溶存させるに充分な
量で添加すればよい。従って、その添加量は、銅変色防
止液の使用状況に応じて適宜決定されるが、一般的な態
様では変色防止剤として５−メチル・１Ｈ−ベンゾトリ
アゾール及び／又は５，６−ジメチル・１Ｈ−ベンゾト
リアゾールから選択されるベンゾトリアゾール誘導体を
含有する無機酸及び／又は有機酸の酸性溶液に、予測さ
れる銅最大汚染モル量の５倍程度、通常銅変色防止液中
に０．０３〜６ｇ／ｌ範囲において添加される。それ以
上銅の汚染が進むと銅変色防止液は更新される。The EDTA chelating agent may be added in an amount sufficient to dissolve the copper accumulated in the copper discoloration preventing solution in the solution in a stabilized form. Therefore, the amount of addition is appropriately determined according to the usage of the copper tarnish preventive solution, but in a general mode, 5-methyl.1H-benzotriazole and / or 5,6-dimethyl.1H is used as the tarnish preventer. -In an acidic solution of an inorganic acid and / or an organic acid containing a benzotriazole derivative selected from benzotriazole, about 5 times the expected maximum molar amount of copper contamination, usually 0.03 to 6 g in a copper tarnish preventive solution. / L range. The copper discoloration preventive solution is renewed when the copper contamination further progresses.
【００３１】また、ＥＤＴＡを添加しない銅変色防止液
を使用して、その使用中、銅変色防止液の劣化が起こる
ことを防ぐため、銅濃度が基準値を越える前にＥＤＴＡ
キレート剤を随時添加してもよい。Further, in order to prevent the deterioration of the copper discoloration preventing solution during use, a copper discoloration preventing solution containing no EDTA is used, and EDTA is added before the copper concentration exceeds the standard value.
A chelating agent may be added at any time.
【００３２】本発明の銅の変色防止液は、基材の銅表面
部分のみに変色防止剤成分をごく微量吸着させ、その働
きにより銅の変色を防止するものであるため、その使用
方法としては前記銀剥離処理を施した基材を水洗後、好
ましくは直ちに２乃至３０秒浸漬するのみでよい。The copper discoloration preventive liquid of the present invention is used for adsorbing a very small amount of the discoloration preventive agent component only on the copper surface portion of the base material and preventing copper discoloration by its function. After washing the base material subjected to the silver stripping treatment with water, it is preferable to immediately immerse the base material for 2 to 30 seconds.
【００３３】（ボンディング接合強度試験）図２に示す
ように、銅ストライクを施し、その上に高速部分銀めっ
き後本発明の銅変色防止液で処理したリードフレームサ
ンプルの銀めっき部分に２５μｍ直径の金ワイヤー（タ
ツタ電線（株）製ＴＧ・Ｕ・ＳＨ−２５）を（株）新川
製型式ＳＷＢ−ＦＡ−ＣＵＢ−１０ボンダーを使用して
超音波併用熱圧着デジタルヘッド方式でボンディングし
そして引張試験（超音波工業（株）製ＵＪ−２４６−１
Ｃの改良型のプル強度試験機を使用）を行なうことによ
り銀めっき部の状態を評価した。ＩＣ実装を模擬して、
左側の第１ボンド部分を金ワイヤーをボール状に溶融し
た後リードフレーム上に熱圧着しそして後右側の第２ボ
ンド部分をワイヤーをリードフレーム上に熱圧着するこ
とにより形成した。第１ボンド部分と第２ボンド部分と
の間隔は１．５ｍｍとした。ボンディング温度は２００
℃とし、適用荷重は第１ボンド部分に対しては５５ｇと
しそして第２ボンド部分に対しては８５ｇとした。(Bonding and Bonding Strength Test) As shown in FIG. 2, a copper strike was applied, and after high speed partial silver plating, the silver plated portion of the lead frame sample treated with the copper tarnish preventive solution of the present invention had a diameter of 25 μm. Gold wire (TG / U / SH-25 manufactured by Tatsuta Electric Wire Co., Ltd.) is bonded by a thermocompression bonding digital head method with ultrasonic wave using Shinkawa Co., Ltd. model SWB-FA-CUB-10 bonder and tensile test. (Ultrasonic Industry Co., Ltd. UJ-246-1
The state of the silver-plated part was evaluated by performing the improved pull strength tester of C). Simulate IC mounting,
The first bond portion on the left side was formed by melting a gold wire into a ball shape, followed by thermocompression bonding onto the lead frame, and the second bond portion on the right side behind was thermocompression bonded onto the lead frame. The distance between the first bond portion and the second bond portion was 1.5 mm. Bonding temperature is 200
C. and applied load was 55 g for the first bond portion and 85 g for the second bond portion.
【００３４】図２においてＡ〜Ｄは切断が起こりうる箇
所を示す。ボンディングが良好な場合は、ワイヤーはＢ
点（金ボールの溶融凝固部との界面であるため組織変化
を生じている一番弱い箇所である）で切断を生じる。銀
めっき面の異常時にはＡ点より接合強度の弱いＤ点で切
断を生じる。従って、引張試験に際してどの箇所で切断
が生じるかを観察することにより、ボンディングの良・
不良状態を知ることが出来る。ボンディング不良数は３
０本のワイヤーの切断試験における不良数を示す。強度
平均値は切断力をｇ単位で示す。In FIGS. 2A to 2D, A to D indicate points where cutting may occur. If the bond is good, the wire is B
Cutting occurs at a point (which is the weakest point where the change in structure occurs because it is the interface with the molten and solidified portion of the gold ball). When the silver-plated surface is abnormal, cutting occurs at point D, which has a weaker bonding strength than point A. Therefore, by observing where the cutting occurs during the tensile test,
You can know the defective state. Number of defective bonding is 3
The number of defects in the cutting test of 0 wires is shown. The average strength indicates the cutting force in g.
【００３５】また、オージェ電子分光法（ＡＥＳ）によ
り銀めっき部の炭素と銅それぞれの検出強度比率をＣ／
Ａｇ及びＣｕ／Ａｇとして測定した。銀面から検出され
る炭素の比率Ｃ／Ａｇは０．２以下が正常で、値が大き
くなる程、炭素（即ちこの場合はベンゾトリアゾール誘
導体）が銀めっき部に吸着されていることを示す。Further, by Auger electron spectroscopy (AES), the detection intensity ratio of each of carbon and copper in the silver-plated portion is C /
It was measured as Ag and Cu / Ag. It is normal for the ratio C / Ag of carbon detected from the silver surface to be 0.2 or less, and the larger the value, the more the carbon (that is, the benzotriazole derivative in this case) is adsorbed on the silver-plated part.
【００３６】先ず、ＥＤＴＡキレート剤を添加しない場
合の銅濃度の影響を調べるために銅変色防止液に燐酸銅
液を添加して銅濃度を０〜６０ｍｇ／ｌの範囲で段階的
に調整し、上記のボンディング接合強度試験並びにＡＥ
Ｓ検出強度比率の測定を行なった。使用した銅変色防止
液は、次の組成である： ピロ燐酸カリウム ：２．５ｇ／ｌ ５−メチル・１Ｈ−ベンゾトリアゾール：５０ｍｇ／ｌ ｐＨ（燐酸にて調整） ：４〜６ これら試験結果を表１に示す。First, in order to investigate the influence of the copper concentration when the EDTA chelating agent is not added, a copper phosphate solution is added to the copper discoloration preventing solution to adjust the copper concentration stepwise in the range of 0 to 60 mg / l. Bonding strength test and AE
The S detection intensity ratio was measured. The copper anti-tarnish solution used has the following composition: potassium pyrophosphate: 2.5 g / l 5-methyl 1H-benzotriazole: 50 mg / l pH (adjusted with phosphoric acid): 4-6 These test results It shows in Table 1.
【００３７】[0037]
【表１】 [Table 1]
【００３８】表１から、銅濃度が６ｍｇ／ｌ以上に増加
すると、不良数が増大し、Ｄにおいても切断が生じ始
め、Ｃ／Ａｇは０．２以上に増大することが確認され
る。これにより、ボンディング性の悪化の原因が銅変色
防止液中への銅の蓄積によるものであることが確認され
る。From Table 1, it is confirmed that when the copper concentration is increased to 6 mg / l or more, the number of defects is increased, cutting starts to occur in D, and C / Ag is increased to 0.2 or more. This confirms that the cause of the deterioration of the bonding property is the accumulation of copper in the copper discoloration preventing liquid.
【００３９】キレート剤として、多くの試薬について試
験を行なったが、ＥＤＴＡ及びその誘導体が特に有効性
を示した。試験した試薬の一例としてトリエタノールア
ミンとＥＤＴＡとの溶出銅に対する安定化を比較した結
果を表２に示す。As a chelating agent, many reagents were tested, and EDTA and its derivatives were shown to be particularly effective. Table 2 shows the results of comparison of the stabilization of triethanolamine and EDTA against eluted copper as an example of the tested reagents.
【００４０】[0040]
【表２】 [Table 2]
【００４１】表２から、トリエタノールアミンを使用し
た場合にはＣ／Ａｇ値が０．２を超えて高くなっている
のに対して、ＥＤＴＡの場合は０．２未満であることが
わかる。From Table 2, it can be seen that the C / Ag value is higher than 0.2 when triethanolamine is used, whereas it is less than 0.2 when EDTA is used.
【００４２】次に、ＥＤＴＡ添加必要濃度を確認するた
めに、銅濃度が０、１０及び６０ｍｇ／ｌの各場合にお
いて、ＥＤＴＡ濃度を銅に対するモル比として０．５〜
５０モルに段階的に増大して効果を調べた。結果を表３
に示す。Next, in order to confirm the required concentration of EDTA addition, when the copper concentration was 0, 10 and 60 mg / l, the EDTA concentration was 0.5 to 0.5 as a molar ratio to copper.
The effect was investigated by gradually increasing it to 50 mol. The results are shown in Table 3.
Shown in.
【００４３】[0043]
【表３】 [Table 3]
【００４４】表３から、銅添加量が１０ｍｇ／ｌでは、
ＥＤＴＡ添加必要量は銅に対するモル比として０．５で
もボンディング不良は発生していないが、Ｃ／Ａｇが
０．２以上になっていることから、Ｃｕ濃度が１０ｍｇ
／ｌを超えると不良が発生する可能性がある。従って、
ＥＤＴＡ添加必要量は銅濃度により異なるが、銅に対す
るモル比として０．５以上、好ましくは１．０以上、よ
り好ましくは、即ち充分の効果を得るには５．０以上必
要である。他方、ＥＤＴＡ添加量があまりに多すぎる
と、変色防止効果に悪影響が出るので１００未満とす
る。従って、ＥＤＴＡ添加量は、銅モル濃度に対して
０．５〜１００、即ち銅変色液中の濃度として０．０３
〜６ｇ／ｌの範囲とする。From Table 3, when the amount of copper added is 10 mg / l,
Even if the amount of EDTA required to be added is 0.5 as the molar ratio to copper, no defective bonding occurs, but since C / Ag is 0.2 or more, the Cu concentration is 10 mg.
If it exceeds / l, defects may occur. Therefore,
The required amount of EDTA to be added varies depending on the copper concentration, but the molar ratio to copper is 0.5 or more, preferably 1.0 or more, more preferably 5.0 or more to obtain a sufficient effect. On the other hand, if the amount of EDTA added is too large, the effect of preventing discoloration is adversely affected, so the amount is made less than 100. Therefore, the amount of EDTA added is 0.5 to 100 with respect to the copper molar concentration, that is, 0.03 as the concentration in the copper discoloring liquid.
The range is up to 6 g / l.
【００４５】（実施例）銅ストライクめっきを施した２
５mm巾×４０mm長さ×０．２mm厚の銅合金製基材を純水
で水洗後、置換防止剤である２−チオバルビツル酸１０
０mg／ｌを含みｐＨ＝１０の前処理液に液温３０℃で１
０秒間浸漬し、純水流水で１０秒間洗浄してから、ＫＡ
ｇ（ＣＮ）2 ：１３０ｇ／ｌ、Ｋ2 ＨＰＯ4 ：１００ｇ
／ｌを含み、ｐＨを８．５に調整された高速銀めっき液
に浸漬し、Ｄｋ＝７０Ａ／dm2 で１０秒間銀めっきを行
った。その後、純水で水洗後中央部（７mm×６mm）を除
いて市販の銀剥離液を用いて溶解除去し、純水で水洗
後、次の変色防止液に１０秒間浸漬した。ベンゾトリア
ゾール誘導体としては、５−メチル・１Ｈ−ベンゾトリ
アゾール或いは５，６−ジメチル・１Ｈ−ベンゾトリア
ゾールを使用した： ピロ燐酸カリウム：２．５ｇ／ｌ ベンゾトリアゾール誘導体：５０ｍｇ／ｌ ＥＤＴＡ：１ｇ／ｌ ｐＨ（燐酸にて調整）：４(Example) 2 plated with copper strike
2-thiobarbituric acid 10 which is a displacement preventive agent is prepared by washing a copper alloy base material of 5 mm width x 40 mm length x 0.2 mm thickness with pure water.
Pretreatment liquid containing 0 mg / l and pH = 10
Soak for 0 seconds, wash with running pure water for 10 seconds, and then KA
g (CN) 2 : 130 g / l, K 2 HPO 4 : 100 g
It was dipped in a high-speed silver plating solution containing / l and having a pH adjusted to 8.5, and silver plating was performed at Dk = 70 A / dm 2 for 10 seconds. Then, after washing with pure water, the central part (7 mm × 6 mm) was removed and the solution was removed by dissolution using a commercially available silver stripper, washed with pure water and then immersed in the following discoloration preventing solution for 10 seconds. As the benzotriazole derivative, 5-methyl 1H-benzotriazole or 5,6-dimethyl 1H-benzotriazole was used: potassium pyrophosphate: 2.5 g / l benzotriazole derivative: 50 mg / l EDTA: 1 g / l pH (adjusted with phosphoric acid): 4
【００４６】このような処理を行った基材を沸騰純水中
に５分間浸漬熱処理し、銅ストライクめっき部（銀剥離
部）の変色を目視により判定した（このような熱処理
は、大気中に放置した場合の加速試験として通常行われ
ている）。変色防止効果は良好であった。また、反復使
用後も、ボンディング性は良好に維持された。The substrate thus treated was immersed in boiling pure water for 5 minutes for heat treatment, and the discoloration of the copper strike-plated portion (silver peeling portion) was visually determined (such heat treatment was performed in the atmosphere. It is usually done as an accelerated test if left unattended). The discoloration preventing effect was good. Also, the bondability was maintained well after repeated use.
【００４７】[0047]
【発明の効果】以上説明したように、本発明に係る銅の
変色防止液及び変色防止方法は、銀より卑な金属、例え
ば銅、銅合金、ニッケル、ニッケル合金及びこれらをめ
っきしたものなどからなる基材に対し高速銀めっきを施
し、銀めっき不要部分に付着した銀を剥離剤で溶解除去
した後に該基材を浸漬することにより、反復使用中ボン
ディング性を損なうことなく銅の変色を防止することが
出来る。従って、本発明は、高速銀めっきを施すリード
フレーム等の電子部品材料を製造する際に、電子部品材
料の信頼性を向上させる。As described above, the copper discoloration preventing liquid and the discoloration preventing method according to the present invention can be applied to metals less base than silver, such as copper, copper alloys, nickel, nickel alloys, and those plated with these. High-speed silver plating is applied to the base material, the silver adhering to the unnecessary silver plating is dissolved and removed with a release agent, and then the base material is dipped to prevent discoloration of copper without damaging the bondability during repeated use. You can do it. Therefore, the present invention improves the reliability of the electronic component material when manufacturing the electronic component material such as a lead frame to which high speed silver plating is applied.
【図１】リードフレームによるＩＣ実装例の要部の断面
図である。FIG. 1 is a cross-sectional view of a main part of an IC mounting example using a lead frame.
【図２】ボンディング接合強度試験のためのリードフレ
ームへのワイヤーボンディングの状況を示す説明図であ
る。FIG. 2 is an explanatory diagram showing a state of wire bonding to a lead frame for a bonding strength test.
１ リードフレーム ２ ＩＣチップ ３ 電極 ４ リード部 ５ アイランド（パッド） ６ ボンディングワイヤ ７ 封止樹脂 ８ 銀めっき部分（ＩＣチップ搭載部） ９ 銀めっき部分 １０ 結合部 1 Lead Frame 2 IC Chip 3 Electrode 4 Lead Part 5 Island (Pad) 6 Bonding Wire 7 Sealing Resin 8 Silver Plated Part (IC Chip Mounted Part) 9 Silver Plated Part 10 Coupling Part
Claims (5)
ンゾトリアゾール及び／又は５，６−ジメチル・１Ｈ−
ベンゾトリアゾールから選択されるベンゾトリアゾール
誘導体を含有する無機酸及び／又は有機酸の酸性溶液に
ＥＤＴＡキレート剤を添加したことを特徴とする銅変色
防止液。1. 5-Methyl.1H-benzotriazole and / or 5,6-dimethyl.1H-as a discoloration preventing agent
A copper discoloration preventing liquid, which comprises adding an EDTA chelating agent to an acidic solution of an inorganic acid and / or an organic acid containing a benzotriazole derivative selected from benzotriazole.
徴とする請求項１の銅変色防止液。2. The copper discoloration preventing liquid according to claim 1, wherein the copper discoloration preventing liquid contains a pH buffering agent.
ンゾトリアゾール及び／又は５，６−ジメチル・１Ｈ−
ベンゾトリアゾールから選択されるベンゾトリアゾール
誘導体を含有する無機酸及び／又は有機酸の酸性溶液か
らなる銅変色防止液の使用中、該銅変色防止液の劣化が
起こることを防ぐためにＥＤＴＡキレート剤を添加する
ことを特徴とする銅変色防止液使用方法。4. 5-Methyl.1H-benzotriazole and / or 5,6-dimethyl.1H- as a discoloration preventing agent
Addition of an EDTA chelating agent in order to prevent deterioration of the copper tarnish preventive solution during use of the copper tarnish preventive solution comprising an acidic solution of an inorganic acid and / or an organic acid containing a benzotriazole derivative selected from benzotriazole. A method of using a copper discoloration preventing liquid, which is characterized by:
徴とする請求項４の銅変色防止液使用方法。5. The method of using a copper tarnish preventive solution according to claim 4, wherein the copper tarnish preventive solution contains a pH buffering agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4069806A JP2687195B2 (en) | 1992-02-19 | 1992-02-19 | Anti-tarnish solution for copper |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4069806A JP2687195B2 (en) | 1992-02-19 | 1992-02-19 | Anti-tarnish solution for copper |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05230675A true JPH05230675A (en) | 1993-09-07 |
| JP2687195B2 JP2687195B2 (en) | 1997-12-08 |
Family
ID=13413366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4069806A Expired - Lifetime JP2687195B2 (en) | 1992-02-19 | 1992-02-19 | Anti-tarnish solution for copper |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2687195B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005105332A (en) * | 2003-09-30 | 2005-04-21 | Nikko Materials Co Ltd | Metal surface treating agent |
| WO2006121516A1 (en) * | 2005-05-06 | 2006-11-16 | Valspar Sourcing, Inc. | Method for improving corrosion resistance of metal surfaces |
| JP2012172154A (en) * | 2011-02-17 | 2012-09-10 | Jx Nippon Mining & Metals Corp | Copper discoloration preventing solution |
| WO2018023048A1 (en) * | 2016-07-29 | 2018-02-01 | Ecolab Usa Inc. | Benzotriazole and tolyltriazole derivatives for corrosion mitigation |
-
1992
- 1992-02-19 JP JP4069806A patent/JP2687195B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005105332A (en) * | 2003-09-30 | 2005-04-21 | Nikko Materials Co Ltd | Metal surface treating agent |
| WO2006121516A1 (en) * | 2005-05-06 | 2006-11-16 | Valspar Sourcing, Inc. | Method for improving corrosion resistance of metal surfaces |
| US10767268B2 (en) | 2005-05-06 | 2020-09-08 | Swimc Llc | Articles having improved corrosion resistance |
| JP2012172154A (en) * | 2011-02-17 | 2012-09-10 | Jx Nippon Mining & Metals Corp | Copper discoloration preventing solution |
| WO2018023048A1 (en) * | 2016-07-29 | 2018-02-01 | Ecolab Usa Inc. | Benzotriazole and tolyltriazole derivatives for corrosion mitigation |
| CN109642331A (en) * | 2016-07-29 | 2019-04-16 | 艺康美国股份有限公司 | For alleviating the benzotriazole and tolytriazole derivative of corrosion |
| US10640473B2 (en) | 2016-07-29 | 2020-05-05 | Ecolab Usa Inc. | Azole derivatives for corrosion mitigation |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2687195B2 (en) | 1997-12-08 |
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